U.S. patent application number 12/317057 was filed with the patent office on 2009-07-02 for heat exchanger.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Yoshiki Katoh.
Application Number | 20090166017 12/317057 |
Document ID | / |
Family ID | 40796698 |
Filed Date | 2009-07-02 |
United States Patent
Application |
20090166017 |
Kind Code |
A1 |
Katoh; Yoshiki |
July 2, 2009 |
HEAT EXCHANGER
Abstract
A flow inlet and a flow outlet are provided at one lateral end
of a core. A second communication passage is provided at the other
lateral end of the core to communicate between an interior of a
downstream side lower tank, which is connected to a furthermost
downstream side passage row that is furthermost from the flow
inlet, and an interior of an upstream side lower tank, which is
connected to a furthermost upstream side passage row that is
furthermost from the flow outlet. The second communication passage
is placed at a location that projects from a body of the core in a
lateral direction or a top-to-bottom direction of the core.
Inventors: |
Katoh; Yoshiki; (Chita-gun,
JP) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Assignee: |
DENSO CORPORATION
Kariya-city
JP
|
Family ID: |
40796698 |
Appl. No.: |
12/317057 |
Filed: |
December 18, 2008 |
Current U.S.
Class: |
165/153 |
Current CPC
Class: |
F28F 9/001 20130101;
F28D 1/05391 20130101; F28D 1/05358 20130101; F28D 2021/0085
20130101 |
Class at
Publication: |
165/153 |
International
Class: |
F28D 1/04 20060101
F28D001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2007 |
JP |
2007-336862 |
Claims
1. A heat exchanger comprising: a core that includes: a plurality
of downstream side flow passage rows, wherein each of the plurality
of downstream side flow passage rows is formed with a plurality of
downstream side tubes, which extend in a top-to-bottom direction of
the core and are placed one after another in a lateral direction of
the core to form a plurality of flow passages, respectively, that
conduct a flow of refrigerant therethrough and are arranged in a
row to form the downstream side flow passage row, and the
downstream side flow passage rows are placed side-by-side in the
lateral direction of the core on a downstream side in a direction
of an air flow, which exchanges heat with the refrigerant; and a
plurality of upstream side flow passage rows, wherein each of the
plurality of upstream side flow passage rows is formed with a
plurality of upstream side tubes, which extend in the top-to-bottom
direction of the core and are placed one after another in the
lateral direction of the core to form a plurality of flow passages,
respectively, that conduct a flow of the refrigerant therethrough
and are arranged in a row to form the upstream side flow passage
row, and the upstream side flow passage rows are placed
side-by-side in the lateral direction of the core on an upstream
side of the downstream side flow passage rows in the direction of
the air flow; a plurality of downstream side header tanks, each of
which supplies the refrigerant to or receives the refrigerant from
the downstream side tubes of each corresponding one of the
downstream side flow passage rows, wherein the plurality of
downstream side header tanks includes: at least one downstream side
upper tank, each of which is connected to upper ends of the flow
passages of each corresponding one of the downstream side flow
passage rows; and at least one downstream side lower tank, each of
which is connected to lower ends of the flow passages of each
corresponding one of the downstream side flow passage rows; a
plurality of upstream side header tanks, each of which supplies the
refrigerant to or receives the refrigerant from the upstream side
tubes of each corresponding one of the upstream side flow passage
rows, wherein the plurality of upstream side header tanks includes:
at least one upstream side upper tank, each of which is connected
to upper ends of the flow passages of each corresponding one of the
upstream side flow passage rows; and at least one upstream side
lower tank, each of which is connected to lower ends of the flow
passages of each corresponding one of the upstream side flow
passage rows; a refrigerant inlet that is located at one lateral
side of the core and is communicated with an interior of a
corresponding one of the downstream side header tanks to supply the
refrigerant to the flow passages of a corresponding one of the
downstream side flow passage rows; a refrigerant outlet that is
located at the one lateral side of the core and is communicated
with an interior of a corresponding one of the upstream side header
tanks to output the refrigerant from the flow passages of a
corresponding one of the upstream side flow passage rows; at least
one downstream side partition wall, each of which is provided in a
corresponding one of the downstream side header tanks to partition
an interior of the corresponding one of the downstream side header
tanks, so that one of the downstream side flow passage rows forms
an upflow passage row, in which the flow of the refrigerant becomes
an upflow, on one lateral side of the downstream side partition
wall, and another one of the downstream side flow passage rows
forms a downflow passage row, in which the flow of the refrigerant
becomes a downflow, on the other lateral side of the downstream
side partition wall; at least one upstream side partition wall,
each of which is provided in a corresponding one of the upstream
side header tanks to partition an interior of the corresponding one
of the upstream side header tanks, so that one of the upstream side
flow passage rows forms an upflow passage row, in which the flow of
the refrigerant becomes an upflow, on one lateral side of the
upstream side partition wall, and another one of the upstream side
flow passage rows forms a downflow passage row, in which the flow
of the refrigerant becomes a downflow, on the other lateral side of
the upstream side partition wall; and a communicating means that is
provided at the other lateral side of the core opposite from the
refrigerant inlet and the refrigerant outlet and is for
communicating between an interior of each corresponding one of the
downstream side header tanks, which is connected to a furthermost
one of the downstream side flow passage rows that is furthermost
from the refrigerant inlet in the lateral direction of the core,
and an interior of each corresponding one of the upstream side
header tanks, which is connected to a furthermost one of the
upstream side flow passage rows that is furthermost from the
refrigerant outlet in the lateral direction of the core, wherein:
the communicating means is placed at a location that projects from
a body of the core in one of the lateral direction and the
up-to-bottom direction of the core; a portion of the refrigerant in
a furthermost one of the downstream side header tanks, which is
furthermost from the refrigerant inlet in the lateral direction of
the core, is conducted toward the upstream side of the air flow
into a furthermost one of the upstream side header tanks located on
an upstream side thereof in the direction of the air flow after
flowing through the communicating means and then flows through the
furthermost one of the upstream side flow passage rows into an
opposed one of the upstream side header tanks, which is opposed to
the furthermost one of the upstream side header tanks in the
top-to-bottom direction of the core; and a rest of the refrigerant,
which remains in the furthermost one of the downstream side header
tanks, flows through the furthermost one of the downstream side
flow passage rows into an opposed one of the downstream side header
tanks, which is opposed to the furthermost one of the downstream
side header tanks in the top-to-bottom direction of the core, and
then flows toward the upstream side of the air flow into the
opposed one of the upstream side header tanks where the rest of the
refrigerant is merged with the portion of the refrigerant supplied
through the communicating means.
2. The heat exchanger according to claim 1, wherein: the
communicating means includes a lower communication passage that
communicates between an interior of a furthermost one of the at
least one downstream side lower tank, which is furthermost from the
refrigerant inlet in the lateral direction of the core, and an
interior of a furthermost one of the at least one upstream side
lower tank, which is furthermost from the refrigerant outlet in the
lateral direction of the core; the heat exchanger further comprises
an upper communication passage that communicates between an
interior of a furthermost one of the at least one downstream side
upper tank, which is furthermost from the refrigerant inlet in the
lateral direction of the core, and an interior of a furthermost one
of the at least one upstream side upper tank, which is furthermost
from the refrigerant outlet in the lateral direction of the core;
and the rest of the refrigerant, which remains in the furthermost
one of the at least one downstream side lower tank, flows upwardly
through the furthermost one of the downstream side flow passage
rows into the furthermost one of the at least one downstream side
upper tank and then flows into the furthermost one of the at least
one upstream side upper tank through the upper communication
passage and is merged with the portion of the refrigerant, which
flows from the furthermost one of the at least one downstream side
lower tank into the furthermost one of the at least one upstream
side lower tank through the lower communication passage and then
flows into the furthermost one of the at least one upstream side
upper tank thorough the furthermost one of the upstream side flow
passage rows.
3. The heat exchanger according to claim 1, wherein: the
communicating means includes an upper communication passage that
communicates between an interior of a furthermost one of the at
least one downstream side upper tank, which is furthermost from the
refrigerant inlet in the lateral direction of the core, and an
interior of a furthermost one of the at least one upstream side
upper tank, which is furthermost from the refrigerant outlet in the
lateral direction of the core; the heat exchanger further comprises
a lower communication passage that communicates between an interior
of a furthermost one of the at least one downstream side lower
tank, which is furthermost from the refrigerant inlet in the
lateral direction of the core, and an interior of a furthermost one
of the at least one upstream side lower tank, which is furthermost
from the refrigerant outlet in the lateral direction of the core;
and the rest of the refrigerant, which remains in the furthermost
one of the at least one downstream side upper tank, flows
downwardly through the furthermost one of the downstream side flow
passage rows into the furthermost one of the at least one
downstream side lower tank and then flows into the furthermost one
of the at least one upstream side lower tank through the lower
communication passage and is merged with the portion of the
refrigerant, which flows from the furthermost one of the at least
one downstream side upper tank into the furthermost one of the at
least one upstream side upper tank through the upper communication
passage and then flows into the furthermost one of the at least one
upstream side lower tank thorough the furthermost one of the
upstream side flow passage rows.
4. The heat exchanger according to claim 1, wherein: the
communicating means includes at least one communication passage
forming member that has a communication passage therein; and each
of the at least one communication passage forming member is formed
as a separate component, which is separate from the plurality of
downstream side header tanks and the plurality of upstream side
header tanks and is assembled integrally to a corresponding one of
the plurality of downstream side header tanks and the plurality of
upstream side header tanks.
5. The heat exchanger according to claim 4, wherein at least a
portion of each of the at least one communication passage forming
member is placed laterally inward of a lateral end of the core in
the lateral direction of the core.
6. The heat exchanger according to claim 5, wherein one of the
plurality of downstream side tubes and the plurality of upstream
side tubes, which is located at the lateral end of the core, or a
side plate, which supports the core, has a longitudinal end portion
that is inserted into an interior of a corresponding one of the at
least one communication passage forming member.
7. The heat exchanger according to claim 5, wherein one of the
plurality of downstream side tubes and the plurality of upstream
side tubes, which is located at the lateral end of the core, or a
side plate, which supports the core, has a longitudinal end portion
that is inserted into an interior of a corresponding one of the
plurality of downstream side header tanks and the plurality of
upstream side header tanks.
8. The heat exchanger according to claim 4, further comprising a
lateral end tube, which is placed at a lateral end of the core and
does not conduct the refrigerant therethrough, wherein the lateral
end tube or a side plate, which supports the core, has a
longitudinal end portion that is bent and contacts a corresponding
one of the at least one communication passage forming member.
9. The heat exchanger according to claim 1, wherein at least one
communication hole is formed through a wall that partitions between
an interior of another furthermost one of the downstream side
header tanks and another furthermost one of the upstream side
header tanks to communicate therebetween.
10. The heat exchanger according to claim 1, wherein: the portion
of the refrigerant in the furthermost one of the downstream side
header tanks is conducted toward the upstream side of the air flow
into the furthermost one of the upstream side header tanks through
a branching passage having a total passage cross sectional area SI;
the rest of the refrigerant in the furthermost one of the
downstream side header tanks flows through the furthermost one of
the downstream side flow passage rows into the opposed one of the
downstream side header tanks, which is opposed to the furthermost
one of the downstream side header tanks in the top-to-bottom
direction of the core, and then flows toward the upstream side of
the air flow into the opposed one of the upstream side header tanks
through a merging passage having a total passage cross sectional
area S2; and the branching passage and the merging passage are
constructed to satisfy a relationship of 0.41.ltoreq.S1/S2.
11. The heat exchanger according to claim 10, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as six; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.71.ltoreq.S1/S2.
12. The heat exchanger according to claim 10, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as five; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.47.ltoreq.S1/S2.
13. The heat exchanger according to claim 10, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as four; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.66.ltoreq.S1/S2.
14. The heat exchanger according to claim 10, wherein the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as three.
15. The heat exchanger according to claim 1, wherein the number of
the remaining downstream side flow passage rows, which are other
than the furthermost one of the downstream side flow passage rows,
is larger than the number of the remaining upstream side flow
passage rows, which are other than the furthermost one of the
upstream side flow passage rows.
16. The heat exchanger according to claim 1, wherein each of the
plurality of downstream side header tanks and the plurality of
upstream side header tanks is formed by integrally joining a
plurality of constituent members, which are stacked one after
another in the lateral direction of the core.
17. The heat exchanger according to claim 1, wherein a total
thickness of one of the plurality of downstream side header tanks
and of an adjacent one of the plurality of upstream side header
tanks, which is measured in the direction of the air flow, is equal
to or less than 48 mm.
18. The heat exchanger according to claim 1, wherein a lateral size
of the furthermost one of the upstream side flow passage rows,
which is measured in the lateral direction of the core, is larger
than that of the furthermost one of the downstream side flow
passage rows.
19. The heat exchanger according to claim 1, wherein a lateral size
of the furthermost one of the downstream side flow passage rows,
which is measured in the lateral direction of the core, is larger
than that of the furthermost one of the upstream side flow passage
rows.
20. The heat exchanger according to claim 1, wherein a thickness of
the downstream side flow passage rows, which is measured in the
direction of the air flow, is larger than that of the upstream side
flow passage rows.
21. A heat exchanger comprising: a core that includes: a plurality
of downstream side flow passage rows, wherein each of the plurality
of downstream side flow passage rows is formed with a plurality of
downstream side tubes, which extend in a top-to-bottom direction of
the core and are placed one after another in a lateral direction of
the core to form a plurality of flow passages, respectively, that
conduct a flow of refrigerant therethrough and are arranged in a
row to form the downstream side flow passage row, and the
downstream side flow passage rows are placed side-by-side in the
lateral direction of the core on a downstream side in a direction
of an air flow, which exchanges heat with the refrigerant; and a
plurality of upstream side flow passage rows, wherein each of the
plurality of upstream side flow passage rows is formed with a
plurality of upstream side tubes, which extend in the top-to-bottom
direction of the core and are placed one after another in the
lateral direction of the core to form a plurality of flow passages,
respectively, that conduct a flow of the refrigerant therethrough
and are arranged in a row to form the upstream side flow passage
row, and the upstream side flow passage rows are placed
side-by-side in the lateral direction of the core on an upstream
side of the downstream side flow passage rows in the direction of
the air flow; a plurality of downstream side header tanks, each of
which supplies the refrigerant to or receives the refrigerant from
the downstream side tubes of each corresponding one of the
downstream side flow passage rows, wherein the plurality of
downstream side header tanks includes: at least one downstream side
upper tank, each of which is connected to upper ends of the flow
passages of each corresponding one of the downstream side flow
passage rows; and at least one downstream side lower tank, each of
which is connected to lower ends of the flow passages of each
corresponding one of the downstream side flow passage rows; a
plurality of upstream side header tanks, each of which supplies the
refrigerant to or receives the refrigerant from the upstream side
tubes of each corresponding one of the upstream side flow passage
rows, wherein the plurality of upstream side header tanks includes:
at least one upstream side upper tank, each of which is connected
to upper ends of the flow passages of each corresponding one of the
upstream side flow passage rows; and at least one upstream side
lower tank, each of which is connected to lower ends of the flow
passages of each corresponding one of the upstream side flow
passage rows; a refrigerant inlet that is located at one lateral
side of the core and is communicated with an interior of a
corresponding one of the downstream side header tanks to supply the
refrigerant to the flow passages of a corresponding one of the
downstream side flow passage rows; a refrigerant outlet that is
located at the one lateral side of the core and is communicated
with an interior of a corresponding one of the upstream side header
tanks to output the refrigerant from the flow passages of a
corresponding one of the upstream side flow passage rows; at least
one downstream side partition wall, each of which is provided in a
corresponding one of the downstream side header tanks to partition
an interior of the corresponding one of the downstream side header
tanks, so that one of the downstream side flow passage rows forms
an upflow passage row, in which the flow of the refrigerant becomes
an upflow, on one lateral side of the downstream side partition
wall, and another one of the downstream side flow passage rows
forms a downflow passage row, in which the flow of the refrigerant
becomes a downflow, on the other lateral side of the downstream
side partition wall; at least one upstream side partition wall,
each of which is provided in a corresponding one of the upstream
side header tanks to partition an interior of the corresponding one
of the upstream side header tanks, so that one of the upstream side
flow passage rows forms an upflow passage row, in which the flow of
the refrigerant becomes an upflow, on one lateral side of the
upstream side partition wall, and another one of the upstream side
flow passage rows forms a downflow passage row, in which the flow
of the refrigerant becomes a downflow, on the other lateral side of
the upstream side partition wall; a lower communication passage
that is provided at the other lateral side of the core opposite
from the refrigerant inlet and the refrigerant outlet and
communicates between an interior of a furthermost one of the at
least one downstream side lower tank, which is furthermost from the
refrigerant inlet in the lateral direction of the core and is
connected to a furthermost one of the downstream side flow passage
rows that is furthermost from the refrigerant inlet in the lateral
direction of the core, and an interior of a furthermost one of the
at least one upstream side lower tank, which is furthermost from
the refrigerant outlet in the lateral direction of the core and is
connected to a furthermost one of the upstream side flow passage
rows that is furthermost from the refrigerant outlet in the lateral
direction of the core, to conduct a portion of the refrigerant in
the furthermost one of the at least one downstream side lower tank
into the furthermost one of the upstream side flow passage rows,
wherein: the portion of the refrigerant from the furthermost one of
the at least one downstream side lower tank flows into the
furthermost one of the at least one upstream side lower tank
through the lower communication passage and then flows into the
furthermost one of the at least one upstream side upper tank after
flowing upwardly thorough the furthermost one of the upstream side
flow passage rows; a rest of the refrigerant, which remains in the
furthermost one of the at least one downstream side lower tank,
flows upwardly through the furthermost one of the downstream side
flow passage rows into the furthermost one of the at least one
downstream side upper tank and then flows into the furthermost one
of the at least one upstream side upper tank and is merged with the
portion of the refrigerant in the furthermost one of the at least
one upstream side upper tank; and a refrigerant inflow opening of
the lower communication passage is an inlet of the lower
communication passage and opens to an interior of the furthermost
one of the at least one downstream side lower tank at a location
that is below lower end openings of the downstream side tubes of
the furthermost one of the downstream side flow passage rows in the
vertical direction.
22. The heat exchanger according to claim 21, wherein: the portion
of the refrigerant in the furthermost one of the downstream side
header tanks is conducted toward the upstream side of the air flow
into the furthermost one of the upstream side header tanks through
a branching passage having a total passage cross sectional area SI;
the rest of the refrigerant in the furthermost one of the
downstream side header tanks flows through the furthermost one of
the downstream side flow passage rows into the opposed one of the
downstream side header tanks, which is opposed to the furthermost
one of the downstream side header tanks in the top-to-bottom
direction of the core, and then flows toward the upstream side of
the air flow into the opposed one of the upstream side header tanks
through a merging passage having a total passage cross sectional
area 52; and the branching passage and the merging passage are
constructed to satisfy a relationship of 0.41.ltoreq.S1/S2.
23. The heat exchanger according to claim 22, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as six; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.71.ltoreq.S1/S2.
24. The heat exchanger according to claim 22, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as five; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.47.ltoreq.S1/S2.
25. The heat exchanger according to claim 22, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as four; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.66.ltoreq.S1/S2.
26. The heat exchanger according to claim 22, wherein the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as three.
27. The heat exchanger according to claim 21, wherein the number of
the remaining downstream side flow passage rows, which are other
than the furthermost one of the downstream side flow passage rows,
is larger than the number of the remaining upstream side flow
passage rows, which are other than the furthermost one of the
upstream side flow passage rows.
28. The heat exchanger according to claim 21, wherein each of the
plurality of downstream side header tanks and the plurality of
upstream side header tanks is formed by integrally joining a
plurality of constituent members, which are stacked one after
another in the lateral direction of the core.
29. The heat exchanger according to claim 21, wherein a total
thickness of one of the plurality of downstream side header tanks
and of an adjacent one of the plurality of upstream side header
tanks, which is measured in the direction of the air flow, is equal
to or less than 48 mm.
30. The heat exchanger according to claim 21, wherein a lateral
size of the furthermost one of the upstream side flow passage rows,
which is measured in the lateral direction of the core, is larger
than that of the furthermost one of the downstream side flow
passage rows.
31. The heat exchanger according to claim 21, wherein a lateral
size of the furthermost one of the downstream side flow passage
rows, which is measured in the lateral direction of the core, is
larger than that of the furthermost one of the upstream side flow
passage rows.
32. The heat exchanger according to claim 21, wherein a thickness
of the downstream side flow passage rows, which is measured in the
direction of the air flow, is larger than that of the upstream side
flow passage rows.
33. A heat exchanger comprising: a core that includes: a plurality
of downstream side flow passage rows, wherein each of the plurality
of downstream side flow passage rows is formed with a plurality of
downstream side tubes, which extend in a top-to-bottom direction of
the core and are placed one after another in a lateral direction of
the core to form a plurality of flow passages, respectively, that
conduct a flow of refrigerant therethrough and are arranged in a
row to form the downstream side flow passage row, and the
downstream side flow passage rows are placed side-by-side in the
lateral direction of the core on a downstream side in a direction
of an air flow, which exchanges heat with the refrigerant; and a
plurality of upstream side flow passage rows, wherein each of the
plurality of upstream side flow passage rows is formed with a
plurality of upstream side tubes, which extend in the top-to-bottom
direction of the core and are placed one after another in the
lateral direction of the core to form a plurality of flow passages,
respectively, that conduct a flow of the refrigerant therethrough
and are arranged in a row to form the upstream side flow passage
row, and the upstream side flow passage rows are placed
side-by-side in the lateral direction of the core on an upstream
side of the downstream side flow passage rows in the direction of
the air flow; a plurality of downstream side header tanks, each of
which supplies the refrigerant to or receives the refrigerant from
the downstream side tubes of each corresponding one of the
downstream side flow passage rows, wherein the plurality of
downstream side header tanks includes: at least one downstream side
upper tank, each of which is connected to upper ends of the flow
passages of each corresponding one of the downstream side flow
passage rows; and at least one downstream side lower tank, each of
which is connected to lower ends of the flow passages of each
corresponding one of the downstream side flow passage rows; a
plurality of upstream side header tanks, each of which supplies the
refrigerant to or receives the refrigerant from the upstream side
tubes of each corresponding one of the upstream side flow passage
rows, wherein the plurality of upstream side header tanks includes:
at least one upstream side upper tank, each of which is connected
to upper ends of the flow passages of each corresponding one of the
upstream side flow passage rows; and at least one upstream side
lower tank, each of which is connected to lower ends of the flow
passages of each corresponding one of the upstream side flow
passage rows; a refrigerant inlet that is located at one lateral
side of the core and is communicated with an interior of a
corresponding one of the downstream side header tanks to supply the
refrigerant to the flow passages of a corresponding one of the
downstream side flow passage rows; a refrigerant outlet that is
located at the one lateral side of the core and is communicated
with an interior of a corresponding one of the upstream side header
tanks to output the refrigerant from the flow passages of a
corresponding one of the upstream side flow passage rows; at least
one downstream side partition wall, each of which is provided in a
corresponding one of the downstream side header tanks to partition
an interior of the corresponding one of the downstream side header
tanks, so that one of the downstream side flow passage rows forms
an upflow passage row, in which the flow of the refrigerant becomes
an upflow, on one lateral side of the downstream side partition
wall, and another one of the downstream side flow passage rows
forms a downflow passage row, in which the flow of the refrigerant
becomes a downflow, on the other lateral side of the downstream
side partition wall; at least one upstream side partition wall,
each of which is provided in a corresponding one of the upstream
side header tanks to partition an interior of the corresponding one
of the upstream side header tanks, so that one of the upstream side
flow passage rows forms an upflow passage row, in which the flow of
the refrigerant becomes an upflow, on one lateral side of the
upstream side partition wall, and another one of the upstream side
flow passage rows forms a downflow passage row, in which the flow
of the refrigerant becomes a downflow, on the other lateral side of
the upstream side partition wall; and an upper communication
passage that is provided at the other lateral side of the core
opposite from the refrigerant inlet and the refrigerant outlet and
communicates between an interior of a furthermost one of the at
least one downstream side upper tank, which is furthermost from the
refrigerant inlet in the lateral direction of the core and is
connected to a furthermost one of the downstream side flow passage
rows that is furthermost from the refrigerant inlet in the lateral
direction of the core, and an interior of a furthermost one of the
at least one upstream side upper tank, which is furthermost from
the refrigerant outlet in the lateral direction of the core and is
connected to a furthermost one of the upstream side flow passage
rows that is furthermost from the refrigerant outlet in the lateral
direction of the core, to conduct a portion of the refrigerant in
the furthermost one of the at least one downstream side upper tank
into the furthermost one of the upstream side flow passage rows,
wherein: the portion of the refrigerant from the furthermost one of
the at least one downstream side upper tank flows into the
furthermost one of the at least one upstream side upper tank
through the upper communication passage and then flows into the
furthermost one of the at least one upstream side lower tank after
flowing downwardly thorough the furthermost one of the upstream
side flow passage rows; a rest of the refrigerant, which remains in
the furthermost one of the at least one downstream side upper tank,
flows downwardly through the furthermost one of the downstream side
flow passage rows into the furthermost one of the at least one
downstream side lower tank and then flows into the furthermost one
of the at least one upstream side lower tank and is merged with the
portion of the refrigerant in the furthermost one of the at least
one upstream side lower tank; and a refrigerant inflow opening of
the upper communication passage is an inlet of the upper
communication passage and opens to an interior of the furthermost
one of the at least one downstream side upper tank at a location
that is above upper end openings of the downstream side tubes of
the furthermost one of the downstream side flow passage rows in the
vertical direction.
34. The heat exchanger according to claim 33, wherein: the portion
of the refrigerant in the furthermost one of the downstream side
header tanks is conducted toward the upstream side of the air flow
into the furthermost one of the upstream side header tanks through
a branching passage having a total passage cross sectional area S1;
the rest of the refrigerant in the furthermost one of the
downstream side header tanks flows through the furthermost one of
the downstream side flow passage rows into the opposed one of the
downstream side header tanks, which is opposed to the furthermost
one of the downstream side header tanks in the top-to-bottom
direction of the core, and then flows toward the upstream side of
the air flow into the opposed one of the upstream side header tanks
through a merging passage having a total passage cross sectional
area S2; and the branching passage and the merging passage are
constructed to satisfy a relationship of 0.41.ltoreq.S1/S2.
35. The heat exchanger according to claim 34, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as six; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.71.ltoreq.S1/S2.
36. The heat exchanger according to claim 34, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as five; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.47.ltoreq.S1/S2.
37. The heat exchanger according to claim 34, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as four; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.66.ltoreq.S1/S2.
38. The heat exchanger according to claim 34, wherein the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as three.
39. The heat exchanger according to claim 33, wherein the number of
the remaining downstream side flow passage rows, which are other
than the furthermost one of the downstream side flow passage rows,
is larger than the number of the remaining upstream side flow
passage rows, which are other than the furthermost one of the
upstream side flow passage rows.
40. The heat exchanger according to claim 33, wherein each of the
plurality of downstream side header tanks and the plurality of
upstream side header tanks is formed by integrally joining a
plurality of constituent members, which are stacked one after
another in the lateral direction of the core.
41. The heat exchanger according to claim 33, wherein a total
thickness of one of the plurality of downstream side header tanks
and of an adjacent one of the plurality of upstream side header
tanks, which is measured in the direction of the air flow, is equal
to or less than 48 mm.
42. The heat exchanger according to claim 33, wherein a lateral
size of the furthermost one of the upstream side flow passage rows,
which is measured in the lateral direction of the core, is larger
than that of the furthermost one of the downstream side flow
passage rows.
43. The heat exchanger according to claim 33, wherein a lateral
size of the furthermost one of the downstream side flow passage
rows, which is measured in the lateral direction of the core, is
larger than that of the furthermost one of the upstream side flow
passage rows.
44. The heat exchanger according to claim 33, wherein a thickness
of the downstream side flow passage rows, which is measured in the
direction of the air flow, is larger than that of the upstream side
flow passage rows.
45. A heat exchanger comprising: a core that includes: a plurality
of downstream side flow passage rows, wherein each of the plurality
of downstream side flow passage rows is formed with a plurality of
downstream side tubes, which extend in a top-to-bottom direction of
the core and are placed one after another in a lateral direction of
the core to form a plurality of flow passages, respectively, that
conduct a flow of refrigerant therethrough and are arranged in a
row to form the downstream side flow passage row, and the
downstream side flow passage rows are placed side-by-side in the
lateral direction of the core on a downstream side in a direction
of an air flow, which exchanges heat with the refrigerant; and a
plurality of upstream side flow passage rows, wherein each of the
plurality of upstream side flow passage rows is formed with a
plurality of upstream side tubes, which extend in the top-to-bottom
direction of the core and are placed one after another in the
lateral direction of the core to form a plurality of flow passages,
respectively, that conduct a flow of the refrigerant therethrough
and are arranged in a row to form the upstream side flow passage
row, and the upstream side flow passage rows are placed
side-by-side in the lateral direction of the core on an upstream
side of the downstream side flow passage rows in the direction of
the air flow; a plurality of downstream side header tanks, each of
which supplies the refrigerant to or receives the refrigerant from
the downstream side tubes of each corresponding one of the
downstream side flow passage rows, wherein the plurality of
downstream side header tanks includes: at least one downstream side
upper tank, each of which is connected to upper ends of the flow
passages of each corresponding one of the downstream side flow
passage rows; and at least one downstream side lower tank, each of
which is connected to lower ends of the flow passages of each
corresponding one of the downstream side flow passage rows; a
plurality of upstream side header tanks, each of which supplies the
refrigerant to or receives the refrigerant from the upstream side
tubes of each corresponding one of the upstream side flow passage
rows, wherein the plurality of upstream side header tanks includes:
at least one upstream side upper tank, each of which is connected
to upper ends of the flow passages of each corresponding one of the
upstream side flow passage rows; and at least one upstream side
lower tank, each of which is connected to lower ends of the flow
passages of each corresponding one of the upstream side flow
passage rows; a refrigerant inlet that is located at one lateral
side of the core and is communicated with an interior of a
corresponding one of the downstream side header tanks to supply the
refrigerant to the flow passages of a corresponding one of the
downstream side flow passage rows; a refrigerant outlet that is
located at the one lateral side of the core and is communicated
with an interior of a corresponding one of the upstream side header
tanks to output the refrigerant from the flow passages of a
corresponding one of the upstream side flow passage rows; at least
one downstream side partition wall, each of which is provided in a
corresponding one of the downstream side header tanks to partition
an interior of the corresponding one of the downstream side header
tanks, so that one of the downstream side flow passage rows forms
an upflow passage row, in which the flow of the refrigerant becomes
an upflow, on one lateral side of the downstream side partition
wall, and another one of the downstream side flow passage rows
forms a downflow passage row, in which the flow of the refrigerant
becomes a downflow, on the other lateral side of the downstream
side partition wall; at least one upstream side partition wall,
each of which is provided in a corresponding one of the upstream
side header tanks to partition an interior of the corresponding one
of the upstream side header tanks, so that one of the upstream side
flow passage rows forms an upflow passage row, in which the flow of
the refrigerant becomes an upflow, on one lateral side of the
upstream side partition wall, and another one of the upstream side
flow passage rows forms a downflow passage row, in which the flow
of the refrigerant becomes a downflow, on the other lateral side of
the upstream side partition wall; and a communicating means that is
provided at the other lateral side of the core opposite from the
refrigerant inlet and the refrigerant outlet and is for
communicating between an interior of each corresponding one of the
downstream side header tanks, which is connected to a furthermost
one of the downstream side flow passage rows that is furthermost
from the refrigerant inlet in the lateral direction of the core,
and an interior of each corresponding one of the upstream side
header tanks, which is connected to a furthermost one of the
upstream side flow passage rows that is furthermost from the
refrigerant outlet in the lateral direction of the core, wherein:
the core has an upstream side lateral plane and a downstream side
lateral plane, which are located on the upstream side and the
downstream side, respectively, in the direction of the air flow;
the core is tilted toward the upstream side in the direction of the
air flow such that the upstream side lateral plane is closer to an
imaginary horizontal plane, which is placed vertically below the at
least one upstream side lower tank, in comparison to the downstream
side lateral plane; a portion of the refrigerant in a furthermost
one of the downstream side header tanks, which is furthermost from
the refrigerant inlet in the lateral direction of the core, is
conducted toward the upstream side of the air flow into a
furthermost one of the upstream side header tanks located on an
upstream side thereof in the direction of the air flow after
flowing through the communicating means and then flows through the
furthermost one of the upstream side flow passage rows into an
opposed one of the upstream side header tanks, which is opposed to
the furthermost one of the upstream side header tanks in the
top-to-bottom direction of the core; and a rest of the refrigerant,
which remains in the furthermost one of the downstream side header
tanks, flows through the furthermost one of the downstream side
flow passage rows into an opposed one of the downstream side header
tanks, which is opposed to the furthermost one of the downstream
side header tanks in the top-to-bottom direction of the core, and
then flows toward the upstream side of the air flow into the
opposed one of the upstream side header tanks where the rest of the
refrigerant is merged with the portion of the refrigerant supplied
through the communicating means.
46. The heat exchanger according to claim 45, wherein: the portion
of the refrigerant in the furthermost one of the downstream side
header tanks is conducted toward the upstream side of the air flow
into the furthermost one of the upstream side header tanks through
a branching passage having a total passage cross sectional area S1;
the rest of the refrigerant in the furthermost one of the
downstream side header tanks flows through the furthermost one of
the downstream side flow passage rows into the opposed one of the
downstream side header tanks, which is opposed to the furthermost
one of the downstream side header tanks in the top-to-bottom
direction of the core, and then flows toward the upstream side of
the air flow into the opposed one of the upstream side header tanks
through a merging passage having a total passage cross sectional
area S2; and the branching passage and the merging passage are
constructed to satisfy a relationship of 0.41.ltoreq.S1/S2.
47. The heat exchanger according to claim 46, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as six; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.71.ltoreq.S1/S2.
48. The heat exchanger according to claim 46, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as five; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.47.ltoreq.S1/S2.
49. The heat exchanger according to claim 46, wherein: the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as four; and the branching passage and the merging passage
are constructed to satisfy a relationship of 0.66.ltoreq.S1/S2.
50. The heat exchanger according to claim 46, wherein the flow of
the refrigerant in the furthermost one of the downstream side flow
passage rows and the flow of the refrigerant in the furthermost one
of the upstream side flow passage rows are directed in a common
direction and are thereby counted as one refrigerant flow path, and
the number of the remaining downstream side flow passage rows,
which are other than the furthermost one of the downstream side
flow passage rows, and the number of the remaining upstream side
flow passage rows, which are other than the furthermost one of the
upstream side flow passage rows, are counted as the number of
refrigerant flow paths in the remaining downstream side flow
passage rows and the remaining upstream side flow passage rows, so
that the total number of the refrigerant flow paths in the core is
counted as three.
51. The heat exchanger according to claim 45, wherein the number of
the remaining downstream side flow passage rows, which are other
than the furthermost one of the downstream side flow passage rows,
is larger than the number of the remaining upstream side flow
passage rows, which are other than the furthermost one of the
upstream side flow passage rows.
52. The heat exchanger according to claim 45, wherein each of the
plurality of downstream side header tanks and the plurality of
upstream side header tanks is formed by integrally joining a
plurality of constituent members, which are stacked one after
another in the lateral direction of the core.
53. The heat exchanger according to claim 45, wherein a total
thickness of one of the plurality of downstream side header tanks
and of an adjacent one of the plurality of upstream side header
tanks, which is measured in the direction of the air flow, is equal
to or less than 48 mm.
54. The heat exchanger according to claim 45, wherein a lateral
size of the furthermost one of the upstream side flow passage rows,
which is measured in the lateral direction of the core, is larger
than that of the furthermost one of the downstream side flow
passage rows.
55. The heat exchanger according to claim 45, wherein a lateral
size of the furthermost one of the downstream side flow passage
rows, which is measured in the lateral direction of the core, is
larger than that of the furthermost one of the upstream side flow
passage rows.
56. The heat exchanger according to claim 45, wherein a thickness
of the downstream side flow passage rows, which is measured in the
direction of the air flow, is larger than that of the upstream side
flow passage rows.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on and incorporates herein by
reference Japanese Patent Application No. 2007-336862 filed on Dec.
27, 2007.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a heat exchanger.
[0004] 2. Description of Related Art
[0005] For example, Japanese Unexamined Patent Publication No.
JP2005-291659A discloses an evaporator as a heat exchanger. This
evaporator has a core (a heat exchanging unit) that includes an
upstream side row of tubes and a downstream side row of tubes,
which are placed one after another in a direction of an air flow.
In each row, the tubes extend in a top-to-bottom direction of the
core and are stacked one after another in a lateral direction of
the core. An upper tank is provided at upper ends of the tubes, and
a lower tank is provided at lower ends of the tubes. A partition
plate is placed in an interior of the upper tank.
[0006] In this evaporator, refrigerant is supplied into the
interior of the upper tank through a refrigerant inlet, which is
provided at one lateral end of the upper tank. Then, the
refrigerant flows from the interior of the upper tank through the
downstream side row of the tubes and the lower tank and makes a
U-turn. Thereafter, the refrigerant is supplied into the upstream
side row of the tubes. Next, the refrigerant flows through the
upstream side row of the tubes and the lower tank and makes a
U-turn. Thereafter, the refrigerant is outputted from a refrigerant
outlet, which is provided next to the refrigerant inlet at the same
side of the core. When the refrigerant flows through the tubes, the
refrigerant exchanges the heat with the air, which flows outside of
the tubes. Thereby, the refrigerant is evaporated.
[0007] In the above heat exchanger, the refrigerant distribution in
the direction of the air flow at the core poses the following
disadvantage. That is, at a further portion of the core, which is
apart from the refrigerant inlet, the refrigerant, which is
discharged from the tank, tends to enter the downstream side row of
the tubes. Therefore, the supply of the refrigerant is biased to
the downstream side. As a result, the desirable refrigerant
performance cannot be achieved.
SUMMARY OF THE INVENTION
[0008] The present invention addresses the above disadvantage.
Thus, it is an objective of the present invention to provide a heat
exchanger, which alleviates biasing of a refrigerant flow that
tends to enter a downstream side flow passage at a further portion
of a core, which is apart from a refrigerant inlet.
[0009] To achieve the objective of the present invention, there is
provided a heat exchanger that includes a core, a plurality of
downstream side header tanks, a plurality of upstream side header
tanks, a refrigerant inlet, a refrigerant outlet, at least one
downstream side partition wall and at least one upstream side
partition wall. The core includes a plurality of downstream side
flow passage rows and a plurality of upstream side flow passage
rows. Each of the plurality of downstream side flow passage rows is
formed with a plurality of downstream side tubes, which extend in a
top-to-bottom direction of the core and are placed one after
another in a lateral direction of the core to form a plurality of
flow passages, respectively, that conduct a flow of refrigerant
therethrough and are arranged in a row to form the downstream side
flow passage row. The downstream side flow passage rows are placed
side-by-side in the lateral direction of the core on a downstream
side in a direction of an air flow, which exchanges heat with the
refrigerant. Each of the plurality of upstream side flow passage
rows is formed with a plurality of upstream side tubes, which
extend in the top-to-bottom direction of the core and are placed
one after another in the lateral direction of the core to form a
plurality of flow passages, respectively, that conduct a flow of
the refrigerant therethrough and are arranged in a row to form the
upstream side flow passage row. The upstream side flow passage rows
are placed side-by-side in the lateral direction of the core on an
upstream side of the downstream side flow passage rows in the
direction of the air flow. Each downstream side header tank
supplies the refrigerant to or receives the refrigerant from the
downstream side tubes of each corresponding one of the downstream
side flow passage rows. The plurality of downstream side header
tanks includes at least one downstream side upper tank and at least
one downstream side lower tank. Each downstream side upper tank is
connected to upper ends of the flow passages of each corresponding
one of the downstream side flow passage rows. Each downstream side
lower tank is connected to lower ends of the flow passages of each
corresponding one of the downstream side flow passage rows. Each
upstream side header tank supplies the refrigerant to or receives
the refrigerant from the upstream side tubes of each corresponding
one of the upstream side flow passage rows. The plurality of
upstream side header tanks includes at least one upstream side
upper tank and at least one upstream side lower tank. Each upstream
side upper tank is connected to upper ends of the flow passages of
each corresponding one of the upstream side flow passage rows. Each
upstream side lower tank is connected to lower ends of the flow
passages of each corresponding one of the upstream side flow
passage rows. The refrigerant inlet is located at one lateral side
of the core and is communicated with an interior of a corresponding
one of the downstream side header tanks to supply the refrigerant
to the flow passages of a corresponding one of the downstream side
flow passage rows. The refrigerant outlet is located at the one
lateral side of the core and is communicated with an interior of a
corresponding one of the upstream side header tanks to output the
refrigerant from the flow passages of a corresponding one of the
upstream side flow passage rows. Each downstream side partition
wall is provided in a corresponding one of the downstream side
header tanks to partition an interior of the corresponding one of
the downstream side header tanks, so that one of the downstream
side flow passage rows forms an upflow passage row, in which the
flow of the refrigerant becomes an upflow, on one lateral side of
the downstream side partition wall, and another one of the
downstream side flow passage rows forms a downflow passage row, in
which the flow of the refrigerant becomes a downflow, on the other
lateral side of the downstream side partition wall. Each upstream
side partition wall is provided in a corresponding one of the
upstream side header tanks to partition an interior of the
corresponding one of the upstream side header tanks, so that one of
the upstream side flow passage rows forms an upflow passage row, in
which the flow of the refrigerant becomes an upflow, on one lateral
side of the upstream side partition wall, and another one of the
upstream side flow passage rows forms a downflow passage row, in
which the flow of the refrigerant becomes a downflow, on the other
lateral side of the upstream side partition wall.
[0010] In one instance, a communicating means may be provided at
the other lateral side of the core opposite from the refrigerant
inlet and the refrigerant outlet. The communicating means is for
communicating between an interior of each corresponding one of the
downstream side header tanks, which is connected to a furthermost
one of the downstream side flow passage rows that is furthermost
from the refrigerant inlet in the lateral direction of the core,
and an interior of each corresponding one of the upstream side
header tanks, which is connected to a furthermost one of the
upstream side flow passage rows that is furthermost from the
refrigerant outlet in the lateral direction of the core. The
communicating means is placed at a location that projects from a
body of the core in one of the lateral direction and the
up-to-bottom direction of the core. A portion of the refrigerant in
a furthermost one of the downstream side header tanks, which is
furthermost from the refrigerant inlet in the lateral direction of
the core, is conducted toward the upstream side of the air flow
into a furthermost one of the upstream side header tanks located on
an upstream side thereof in the direction of the air flow after
flowing through the communicating means and then flows through the
furthermost one of the upstream side flow passage rows into an
opposed one of the upstream side header tanks, which is opposed to
the furthermost one of the upstream side header tanks in the
top-to-bottom direction of the core. A rest of the refrigerant,
which remains in the furthermost one of the downstream side header
tanks, flows through the furthermost one of the downstream side
flow passage rows into an opposed one of the downstream side header
tanks, which is opposed to the furthermost one of the downstream
side header tanks in the top-to-bottom direction of the core, and
then flows toward the upstream side of the air flow into the
opposed one of the upstream side header tanks where the rest of the
refrigerant is merged with the portion of the refrigerant supplied
through the communicating means.
[0011] In another instance, a lower communication passage may be
provided at the other lateral side of the core opposite from the
refrigerant inlet and the refrigerant outlet. The lower
communication passage communicates between an interior of a
furthermost one of the at least one downstream side lower tank,
which is furthermost from the refrigerant inlet in the lateral
direction of the core and is connected to a furthermost one of the
downstream side flow passage rows that is furthermost from the
refrigerant inlet in the lateral direction of the core, and an
interior of a furthermost one of the at least one upstream side
lower tank, which is furthermost from the refrigerant outlet in the
lateral direction of the core and is connected to a furthermost one
of the upstream side flow passage rows that is furthermost from the
refrigerant outlet in the lateral direction of the core, to conduct
a portion of the refrigerant in the furthermost one of the at least
one downstream side lower tank into the furthermost one of the
upstream side flow passage rows. The portion of the refrigerant
from the furthermost one of the at least one downstream side lower
tank flows into the furthermost one of the at least one upstream
side lower tank through the lower communication passage and then
flows into the furthermost one of the at least one upstream side
upper tank after flowing upwardly thorough the furthermost one of
the upstream side flow passage rows. A rest of the refrigerant,
which remains in the furthermost one of the at least one downstream
side lower tank, flows upwardly through the furthermost one of the
downstream side flow passage rows into the furthermost one of the
at least one downstream side upper tank and then flows into the
furthermost one of the at least one upstream side upper tank and is
merged with the portion of the refrigerant in the furthermost one
of the at least one upstream side upper tank. The refrigerant
inflow opening of the lower communication passage is an inlet of
the lower communication passage and opens to an interior of the
furthermost one of the at least one downstream side lower tank at a
location that is below lower end openings of the downstream side
tubes of the furthermost one of the downstream side flow passage
rows in the vertical direction.
[0012] In a further instance, an upper communication passage may be
provided at the other lateral side of the core opposite from the
refrigerant inlet and the refrigerant outlet. The upper
communication passage communicates between an interior of a
furthermost one of the at least one downstream side upper tank,
which is furthermost from the refrigerant inlet in the lateral
direction of the core and is connected to a furthermost one of the
downstream side flow passage rows that is furthermost from the
refrigerant inlet in the lateral direction of the core, and an
interior of a furthermost one of the at least one upstream side
upper tank, which is furthermost from the refrigerant outlet in the
lateral direction of the core and is connected to a furthermost one
of the upstream side flow passage rows that is furthermost from the
refrigerant outlet in the lateral direction of the core, to conduct
a portion of the refrigerant in the furthermost one of the at least
one downstream side upper tank into the furthermost one of the
upstream side flow passage rows. The portion of the refrigerant
from the furthermost one of the at least one downstream side upper
tank flows into the furthermost one of the at least one upstream
side upper tank through the upper communication passage and then
flows into the furthermost one of the at least one upstream side
lower tank after flowing downwardly thorough the furthermost one of
the upstream side flow passage rows. A rest of the refrigerant,
which remains in the furthermost one of the at least one downstream
side upper tank, flows downwardly through the furthermost one of
the downstream side flow passage rows into the furthermost one of
the at least one downstream side lower tank and then flows into the
furthermost one of the at least one upstream side lower tank and is
merged with the portion of the refrigerant in the furthermost one
of the at least one upstream side lower tank. A refrigerant inflow
opening of the upper communication passage is an inlet of the upper
communication passage and opens to an interior of the furthermost
one of the at least one downstream side upper tank at a location
that is above upper end openings of the downstream side tubes of
the furthermost one of the downstream side flow passage rows in the
vertical direction.
[0013] In a further instance, a communicating means may be provided
at the other lateral side of the core opposite from the refrigerant
inlet and the refrigerant outlet. The communicating means is for
communicating between an interior of each corresponding one of the
downstream side header tanks, which is connected to a furthermost
one of the downstream side flow passage rows that is furthermost
from the refrigerant inlet in the lateral direction of the core,
and an interior of each corresponding one of the upstream side
header tanks, which is connected to a furthermost one of the
upstream side flow passage rows that is furthermost from the
refrigerant outlet in the lateral direction of the core. The core
has an upstream side lateral plane and a downstream side lateral
plane, which are located on the upstream side and the downstream
side, respectively, in the direction of the air flow. The core is
tilted toward the upstream side in the direction of the air flow
such that the upstream side lateral plane is closer to an imaginary
horizontal plane, which is placed vertically below the at least one
upstream side lower tank, in comparison to the downstream side
lateral plane. A portion of the refrigerant in a furthermost one of
the downstream side header tanks, which is furthermost from the
refrigerant inlet in the lateral direction of the core, is
conducted toward the upstream side of the air flow into a
furthermost one of the upstream side header tanks located on an
upstream side thereof in the direction of the air flow after
flowing through the communicating means and then flows through the
furthermost one of the upstream side flow passage rows into an
opposed one of the upstream side header tanks, which is opposed to
the furthermost one of the upstream side header tanks in the
top-to-bottom direction of the core. A rest of the refrigerant,
which remains in the furthermost one of the downstream side header
tanks, flows through the furthermost one of the downstream side
flow passage rows into an opposed one of the downstream side header
tanks, which is opposed to the furthermost one of the downstream
side header tanks in the top-to-bottom direction of the core, and
then flows toward the upstream side of the air flow into the
opposed one of the upstream side header tanks where the rest of the
refrigerant is merged with the portion of the refrigerant supplied
through the communicating means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention, together with additional objectives, features
and advantages thereof, will be best understood from the following
description, the appended claims and the accompanying drawings in
which:
[0015] FIG. 1 is a perspective view showing an evaporator (an
example of a heat exchanger) according to a first embodiment of the
present invention;
[0016] FIG. 2 is a partial perspective enlarged view showing a
portion of a core of the evaporator;
[0017] FIG. 3 is a schematic view showing a structure and a
refrigerant flow of the evaporator according to the first
embodiment;
[0018] FIG. 4 is an exploded view showing a structure of a
communication passage forming member of the evaporator according to
the first embodiment;
[0019] FIG. 5 is a schematic view showing a structure and a
refrigerant flow of an evaporator according to a second embodiment
of the present invention;
[0020] FIG. 6 is a schematic diagram seen in a direction opposite
from an X-direction, showing a positional relationship of a
communication passage inlet and a communication passage outlet
relative to a downstream side flow passage row and an upstream side
flow passage row according to the second embodiment;
[0021] FIG. 7 is a schematic view showing a structure and a
refrigerant flow of an evaporator according to a third embodiment
of the present invention;
[0022] FIG. 8 is a schematic view showing a structure and a
refrigerant flow of an evaporator according to a fourth embodiment
of the present invention;
[0023] FIG. 9 is a schematic view showing a structure and a
refrigerant flow of an evaporator according to a fifth embodiment
of the present invention;
[0024] FIG. 10 is a schematic view showing a structure and a
refrigerant flow of an evaporator according to a sixth embodiment
of the present invention;
[0025] FIG. 11 is a schematic diagram seen in an X direction,
showing a positional relationship of a communication passage inlet
and a communication passage outlet relative to a downstream side
flow passage row and an upstream side flow passage row according to
the sixth embodiment;
[0026] FIG. 12 is a schematic view showing a structure and a
refrigerant flow of an evaporator according to a seventh embodiment
of the present invention;
[0027] FIG. 13 is a schematic view seen from a direction opposite
from a Z-direction, showing a relationship of communication holes
relative to a downstream side flow passage row and an upstream side
flow passage row according to the seventh embodiment;
[0028] FIG. 14 is a schematic view showing a structure and a
refrigerant flow of an evaporator according to an eighth embodiment
of the present invention;
[0029] FIG. 15 is a schematic view seen from a direction opposite
from a Z-direction, showing a relationship of communication holes
relative to a downstream side flow passage row and an upstream side
flow passage row according to the eighth embodiment;
[0030] FIG. 16 is a schematic view showing a structure and a
refrigerant flow of an evaporator (a case where the number of
refrigerant flow paths is six) according to a ninth embodiment of
the present invention;
[0031] FIG. 17 is a schematic view showing a structure and a
refrigerant flow of an evaporator (a case where the number of
refrigerant flow paths is five) according to a tenth embodiment of
the present invention;
[0032] FIG. 18 is a schematic view showing a structure and a
refrigerant flow of an evaporator (a case where the number of
refrigerant flow paths is five) according to an eleventh embodiment
of the present invention;
[0033] FIG. 19 is a schematic view showing a structure and a
refrigerant flow of an evaporator (a case where the number of
refrigerant flow paths is four) according to a twelfth embodiment
of the present invention;
[0034] FIG. 20 is a schematic view showing a structure and a
refrigerant flow of an evaporator (a case where the number of
refrigerant flow paths is three) according to a thirteenth
embodiment of the present invention;
[0035] FIG. 21 is a side view showing a positioning state of an
evaporator according to a fourteenth embodiment of the present
invention;
[0036] FIG. 22 is a partial schematic side view showing an interior
of an upper header tank at a furthermost portion of the evaporator
and a refrigerant flow quantity relationship in an interior of a
core of the evaporator according to the fourteenth embodiment;
[0037] FIG. 23 is a partial schematic side view showing an interior
of a lower header tank at a furthermost portion of the evaporator
and a refrigerant flow quantity relationship in an interior of the
core of the evaporator according to the fourteenth embodiment;
[0038] FIG. 24 is a partial side view showing an upper header tank
of an evaporator according to a fifteenth embodiment of the present
invention;
[0039] FIG. 25 is a partial front view seen from an X-direction,
showing a flow inlet at the upper header tank of FIG. 24;
[0040] FIG. 26 is a graph showing a result of a computation
obtained under a predetermined condition for a relationship between
a tank outer diameter and a pressure loss in an interior of the
tank according to the fifteenth embodiment;
[0041] FIG. 27 is a schematic diagram for designing an appropriate
condition of a flow quantity of refrigerant, which flows in an
upstream side flow passage row, and a flow quantity of a
refrigerant, which flows in a downstream side flow passage row,
according to a sixteenth embodiment of the present invention;
[0042] FIG. 28 is a diagram showing a result of a computation of a
ratio between a total passage cross sectional area of a branching
passage and a total passage cross sectional area of a merging
passage for various numbers of refrigerant flow paths according to
the sixteenth embodiment;
[0043] FIG. 29 is a schematic view showing a structure and a
refrigerant flow of an evaporator according to a seventeenth
embodiment of the present invention;
[0044] FIG. 30 is a schematic diagram showing a modification of the
evaporator of FIG. 29;
[0045] FIG. 31 is a schematic front view showing a relationship
between communication passage forming member and a core of an
evaporator according to an eighteenth embodiment of the present
invention;
[0046] FIG. 32 is a schematic partial front view showing a
modification of the evaporator of FIG. 31; and
[0047] FIG. 33 is a schematic partial front view showing another
modification of the evaporator of FIG. 31.
DETAILED DESCRIPTION OF THE INVENTION
[0048] Various embodiments of the present invention will be
described with reference to the accompanying drawings. In the
following embodiments, similar components are indicated by the same
reference numerals and will not be redundantly described to simply
the description. Furthermore, it should be noted that any one or
more components of one or more of the following embodiments may be
freely combined with any one or more components of any other one or
more of the following embodiments as long as there is no reason
that hinders implementation of such a combination.
First Embodiment
[0049] A first embodiment of the present invention will be
described with reference to FIGS. 1 to 4. FIG. 1 is a schematic
perspective view showing an entire structure of an evaporator 1
according to the first embodiment. FIG. 2 is a partial enlarged
perspective view of a core 100, which is a heat exchanging unit of
the evaporator 1. FIG. 3 is a schematic diagram showing the
structure of the evaporator 1 and a flow of refrigerant therein
according to the present embodiment.
[0050] The evaporator 1 of the present embodiment is a component of
a refrigeration cycle, which is installed in a vehicle air
conditioning system. The evaporator 1 serves as a heat exchanger.
In this refrigeration cycle, the refrigerant is compressed by a
compressor and becomes the high temperature and high pressure
refrigerant. Thereafter, the refrigerant is cooled through a
radiator and is depressurized through an expansion device to become
the low temperature and low pressure refrigerant. The refrigerant
is then supplied to the evaporator 1 and is evaporated
therethrough. In the present embodiment, R134a (one of
hydro-fluoro-carbon refrigerants) is used as the refrigerant. The
radiator serves as a condenser, which condenses the refrigerant
discharged from the compressor.
[0051] As shown in FIG. 1, the evaporator 1 includes a core 100, an
upper header tank (forming corresponding upstream side and
downstream side upper tanks described below) 3 and a lower header
tank (forming corresponding upstream side and downstream side lower
tanks described below) 4. As shown in FIG. 2, the core 100 includes
a plurality of tubes 20, a plurality of outer fins 26 and side
plates 28. The tubes 20 and the outer fins 26 are alternately
staked in one direction (hereinafter, referred to as a stacking
direction). Each of the side plates 28 is placed on an outer side
of a corresponding one of opposed outermost outer fins 26 in the
stacking direction. The outer fins 26 serve as heat exchanging
fins. In FIGS. 1 and 2, an X-direction is the stacking direction
(lateral direction), along which the tubes 20 are placed one after
another. Furthermore, a Z-direction is a flow direction of the air,
and a Y-direction is a longitudinal direction (extending direction)
of the respective tubes and corresponds to a top-to-bottom
direction of the core 100. In FIG. 1, a width W of the core 100 is
measured in the X-direction, and a height H of the core 100 is
measured in the Y-direction. Also, a thickness T of the core 100 is
measured in the Z-direction.
[0052] In the core 100 of the evaporator 1, the vertically
extending tubes 20 are arranged in a plurality of rows, each of
which extends in the X-direction. The rows of the tubes 20 include
at least two rows (an upstream side row and a downstream side row)
of tubes 20, which are placed one after another in the Z-direction,
i.e., the direction of the air flow (hereinafter, also simply
referred to as the air flow direction). The air serves as an
external fluid, which exchanges the heat with the refrigerant that
flows through the tubes 20. Each tube 20 is formed, for example, by
bending a thin aluminum strip plate into a generally flat tubular
member that has a generally planar cross section, which is
generally planar in a direction perpendicular to the longitudinal
direction (internal fluid passage direction) of the tubular member.
Inner fins (not shown) are provided in the interior of the tube 20
and are joined to an inner surface of the tube 20.
[0053] In the core 100, the rows of the tubes 20 are divided into a
predetermined number of downstream side flow passage rows 21 of the
tubes 20 (these tubes 20 will be hereinafter referred to as tubes
20a) placed on the downstream side in the air flow direction and a
predetermined number of upstream side flow passage rows 22 of the
tubes 20 (these tubes will be hereinafter referred to as tubes 20b)
placed on the upstream side in the air flow direction with respect
to the downstream side flow passage rows 21 of the tubes 20a. In
each downstream side flow passage row 21, the tubes 20a are placed
one after another in the X-direction (lateral direction) to form a
plurality of flow passages. Also, in each upstream side flow
passage row 22, the tubes 20b are placed one after another in the
X-direction (lateral direction) to form a plurality of flow
passages. The downstream side flow passage rows 21 and the upstream
side flow passage rows 22 are respectively placed on the downstream
side and the upstream side in the air flow direction and are
integrated together to form the core 100. Here, the number of the
downstream side flow passage rows 21 and the number of the upstream
side flow passage rows 22 are determined based on a pattern of the
refrigerant flow (hereinafter, referred to as a refrigerant flow
pattern) in the core 100. Furthermore, with reference to FIG. 2, a
thickness Ta of the downstream side flow passage row 21, which is
measured in the direction of the air flow, is set to be generally
the same as a thickness Th of the upstream side flow passage row
22, which is measured in the direction of the air flow, in this
embodiment.
[0054] In each downstream side flow passage row 21, the refrigerant
in each of the tubes 20a flows in a common direction. Furthermore,
the downstream side flow passage rows 21 are communicated with each
other through downstream side header tanks 11 (the downstream side
upper tank of the upper header tank 3 and the downstream side lower
tank of the lower header tank 4). In each upstream side flow
passage row 22, the refrigerant in each of the tubes 20b flows in a
common direction. Furthermore, the upstream side flow passage rows
22 are communicated with each other through upstream side header
tanks 12 (the upstream side upper tank of the upper header tank 3
and the upstream side lower tank of the lower header tank 4).
[0055] The outer fins 26 are corrugate fins and have, for example,
louvers (not shown) formed on the surfaces of the outer fins 26 to
increase the heat exchange efficiency. The outer fins 26 are joined
to the outer surfaces of the tube 20 (tubes 20a, 20b) by
brazing.
[0056] The side plates 28 serve as reinforcing members, which
reinforce the structural strength of the core 100. Each side plate
28 is formed through a press working process of an aluminum plate.
Each of two opposed longitudinal end portions of each side plate 28
is configured into a flat plate form, and the rest of the side
plate, which is other than the longitudinal end portions, is
configured into a generally U-shaped form, which opens toward the
outer side in the stacking direction of the tubes 20 (20a, 20b).
Furthermore, the side plate 28 is fixed to the corresponding outer
fin 26 by brazing.
[0057] The downstream side header tanks 11 include the downstream
side upper tank (downstream side upper tank portion) 31 and the
downstream side lower tank (downstream side lower tank portion) 41.
The downstream side upper tank 31 is connected to upper ends of the
tubes 20a of the downstream side flow passage rows 21, and the
downstream side lower tank 41 is connected to lower ends of the
tubes 20a of the downstream side flow passage rows 21. These upper
and lower tanks 31, 41 form chambers (interior spaces), to which
the refrigerant from the tubes 20a of the downstream side flow
passage rows 21 is supplied and from which the refrigerant is
distributed into the tubes 20a of the downstream side flow passage
rows 21.
[0058] A connector 5 in a form of a block is fixed to a left side
end (an end in a direction opposite from the X-direction) of the
downstream side upper tank 31 by brazing. The connector 5 has a
flow inlet 51, which serves as a refrigerant inlet that is
communicated with the interior of the downstream side header tank
11 to conduct the refrigerant into the core 100. The flow inlet 51
is communicated with a left end of the downstream side lower tank
41 (an end in the direction opposite from the X-direction) through
a side flow passage 2 defined in, for example, the interior side of
the side plate 28.
[0059] The upstream side header tanks 12 include the upstream side
upper tank 32 and the upstream side lower tank 42. The upstream
side upper tank 32 is connected to upper ends of the tubes 20b of
the upstream side flow passage rows 22, and the upstream side lower
tank 42 is connected to lower ends of the tubes 20b of the upstream
side flow passage rows 22. These upper and lower tanks 32, 42 form
chambers (interior spaces), to which the refrigerant from the tubes
20a of the upstream side flow passage rows 22 is supplied and from
which the refrigerant is distributed into the tubes 20a of the
upstream side flow passage rows 22.
[0060] The connector 5 in the form of the block is fixed to a left
side end (an end in a direction opposite from the X-direction) of
the upstream side upper tank 32 by brazing. The connector 5 has a
flow outlet 52, which serves as a refrigerant outlet that is
communicated with the interior of the upstream side header tank 12
to conduct the refrigerant out of the core 100 toward the external
device in the refrigerant cycle. As discussed above, the flow inlet
51 and the flow outlet 52 are respectively provided to the end of
the downstream side header tank 11 and the end of the upstream side
header tank 12 on the common lateral side of the core 100.
[0061] The upper header tank 3 is divided into two halves, which
are referred to as a tank header and a plate header, in the
longitudinal direction (the extending direction, the internal fluid
passage direction) of the tubes 20 (20a, 20b). The tank header is
placed on the side opposite from the tubes 20 (20a, 20b), and the
plate header is placed on the side where the tubes 20 (20a, 20b)
are located. Each corresponding longitudinal end opening of the
upper header tank 3 is closed with a cap. The upper header tank 3
includes the downstream side upper tank (downstream side upper tank
portion) 31 and the upstream side upper tank (upstream side upper
tank portion) 32. Each of the tank header and the plate header has
a cross section that includes two semi-spherical parts or two
semi-rectangular parts, which are connected side-by-side.
Furthermore, each of the tank header and the plate header is formed
through a press working process of an aluminum plate. The tank
header and the plate header are engaged with each other and are
securely brazed together to form a tubular body, in which the two
interior spaces are placed one after another in the air flow
direction to form the downstream side upper tank 31 and the
upstream side upper tank 32. The cap, which is formed through a
press working of an aluminum plate, is brazed to each corresponding
longitudinal end opening of the downstream side upper tank 31 and
of the upstream side upper tank 32 to close the same.
[0062] A plurality of separators (see FIG. 3) is fixed by brazing
in the upper header tank 3 to divide each of the two internal
spaces into two parts in the X-direction (the lateral direction).
Specifically, the interior of the upstream side upper tank 32 is
divided by the separator (upstream side upper partition wall) 32a
into two spaces in the lateral direction of the core 100. Also, the
interior of the downstream side upper tank 31 is divided by the
separator (downstream side upper partition wall) 31a into two
spaces in the lateral direction of the core 100.
[0063] The downstream side flow passage rows 21 include downstream
side flow passage rows 21a, 210 (serving as upflow passage rows)
and a downstream side flow passage row 21b (serving as a downflow
passage row). The separator 31a is provided in the downstream side
upper tank 31 in such a manner that one of the downstream side flow
passage rows 21a, 210 is placed adjacent to the separator 31a on
one lateral side thereof, and the downstream side flow passage row
21b is placed adjacent to the separator 31a on the other lateral
side thereof, thereby dividing between the upflow and the downflow.
The, upstream side flow passage rows 22 include upstream side flow
passage rows 22a, 220 (serving as upflow passage rows) and an
upstream side flow passage row 22b (serving as a downflow passage
row). The separator 32a is provided in the upstream side upper tank
32 in such a manner that one of the upstream side flow passage rows
22a, 220 is placed adjacent to the separator 32a on one lateral
side thereof, and the upstream side flow passage row 22b is placed
adjacent to the separator 32a on the other lateral side thereof,
thereby dividing between the upflow and the downflow.
[0064] In the right side region of the downstream side upper tank
31, which is located on the right side of the separator 31a (the
side of the separator 31a in the X-direction) in FIG. 3, a
plurality of communication holes 300 is provided to communicate
between the right lateral side space of the downstream side upper
tank 31 and the right lateral side space of the upstream side upper
tank 32.
[0065] The communication holes 300 are formed through a partition
wall, which partitions the tank interior at the other lateral side,
which is opposite from the lateral side wherein the flow inlet 51
and the flow outlet 52 are provided. The communication holes 300
serve as a communicating means for communicating between the
interior of the furthermost downstream side upper tank 311 (also
referred to as a furthermost downstream side upper tank portion, a
furthermost downstream side upper tank interior, or a furthermost
downstream side upper tank chamber of the downstream side upper
tank 31), which is connected to the downstream side flow passage
row 210 that is furthermost from the flow inlet 51 (hereinafter,
also referred to as a furthermost downstream side flow passage row
210 at the furthermost portion of the core 100, which is
furthermost from the flow inlet 51 and the flow outlet 52 in the
X-direction), and the interior of the furthermost upstream side
upper tank 321 (also referred to as a furthermost upstream side
upper tank portion, a furthermost upstream side upper tank
interior, or a furthermost upstream side upper tank chamber of the
upstream side upper tank 32), which is connected to the upstream
side flow passage row 220 that is furthermost from the flow outlet
52 (hereinafter, also referred to as a furthermost upstream side
flow passage row 220 at the furthermost portion of the core 100).
The communication holes 300 also form a part of a first
communication passage 33, through which the refrigerant in the
furthermost downstream side upper tank 311 flows toward the
upstream side of the air flow and finally into the furthermost
upstream side upper tank 321.
[0066] The first communication passage 33 is an upper communication
passage, which communicates between the interior of the furthermost
downstream side upper tank 311, which is furthermost from the flow
inlet 51 in the lateral direction, and the furthermost upstream
side upper tank 321, which is furthermost from the flow outlet 52
in the lateral direction. The interior of the downstream side upper
tank 311 is the furthermost one of the two partitioned spaces,
which are partitioned from each other in the lateral direction by
the separator 31a, with respect to the flow inlet 51. The interior
of the upstream side upper tank 321 is the furthermost one of the
two partitioned spaces, which are partitioned from each other in
the lateral direction by the separator 32a, with respect to the
flow outlet 52.
[0067] The lower header tank 4 is similar to the upper header tank
3 and thereby includes the tank header and the plate header to form
the tubular body. Caps are provided to longitudinal end portions,
respectively, of the tubular body. The lower header tank 4 includes
the downstream side lower tank 41 and the upstream side lower tank
42.
[0068] A plurality of separators (see FIG. 3) is fixed by brazing
in the lower header tank 3 to divide each of the two internal
spaces into two parts in the X-direction (the lateral direction).
Specifically, the interior of the upstream side lower tank 42 is
divided by the separator (downstream side lower partition wall) 42a
into two spaces in the lateral direction of the core 100. Also, the
interior of the downstream side lower tank 41 is divided by the
separator (downstream side lower partition wall) 41a into two
spaces in the lateral direction of the core 100.
[0069] The separator 41a is provided in the downstream side lower
tank 41 in such a manner that one of the downstream side flow
passage rows 21a, 210 is placed adjacent to the separator 41a on
one lateral side thereof, and the downstream side flow passage row
21b is placed adjacent to the separator 41a on the other lateral
side thereof, thereby dividing between the upflow and the downflow.
The separator 42a is provided in the upstream side lower tank 42 in
such a manner that one of the upstream side flow passage rows 22a,
220 is placed adjacent to the separator 42a on one lateral side
thereof, and the upstream side flow passage row 22b is placed
adjacent to the separator 42a on the other lateral side thereof,
thereby dividing between the upflow and the downflow.
[0070] In the right side region of the downstream side lower tank
41, which is located on the right side of the separator 41a (the
side of the separator 41a in the X-direction) in FIG. 3, a second
communication passage 43 is provided to communicate between the
right lateral side space of the downstream side lower tank 41 and
the right lateral side space of the upstream side lower tank
42.
[0071] The second communication passage 43 is a lower communication
passage (a communicating means), which communicates between the
interior of the furthermost downstream side lower tank 411 (a
furthermost downstream side lower tank portion, a furthermost
downstream side lower tank interior, or a furthermost downstream
side lower tank chamber of the downstream side lower tank 41),
which is furthermost from the flow inlet 51 in the lateral
direction, and the furthermost upstream side lower tank 421 (a
furthermost upstream side lower tank portion, a furthermost
upstream side lower tank interior, or a furthermost upstream side
lower tank chamber of the upstream side lower tank 42), which is
furthermost from the flow outlet 52 in the lateral direction. The
interior of the downstream side lower tank 411 is the furthermost
one of the two partitioned spaces, which are partitioned from each
other in the lateral direction by the separator 41a, with respect
to the flow inlet 51. The interior of the upstream side lower tank
421 is the furthermost one of the two partitioned spaces, which are
partitioned from each other in the lateral direction by the
separator 42a, with respect to the flow outlet 52.
[0072] The second communication passage 43 is formed in an interior
of a communication passage forming member 44. A communication
passage inlet 441a of the second communication passage 43, through
which the refrigerant is supplied into the second communication
passage 43, includes one or more holes that extend through in the
X-direction (the lateral direction) to communicate between the
interior of the furthermost downstream side lower tank 411 and the
interior of the communication passage forming member 44. A
communication passage outlet 441b of the second communication
passage 43, through which the refrigerant is outputted from the
second communication passage 43, includes one or more holes that
extend through in the X-direction (the lateral direction) to
communicate between the interior of the communication passage
forming member 44 and the interior of the furthermost downstream
side lower tank 421.
[0073] The communication passage forming member 44 is a separate
component, which is formed separately from the downstream side
lower tank 411 and the upstream side lower tank 421 and is
integrally fixed to the downstream side lower tank 411 and the
upstream side lower tank 421 by, for example, brazing. The
communication passage forming member 44 is placed at a location,
which projects laterally from the body of the core 100 (the body of
the core 100 being made by the refrigerant conducting tubes 20 and
the fins 26). In the present embodiment, the communication passage
forming member 44 is configured into a box shape that projects
laterally from the furthermost downstream side lower tank 411.
Furthermore, the communication passage forming member 44 is made of
the material that is similar to or is the same as that of the
furthermost downstream side lower tank 411.
[0074] FIG. 4 is an exploded view showing the communication passage
forming member 44. As shown in FIG. 4, the communication passage
forming member 44 includes a planar member 441 and a dome member
44b. The planar member 441 has the communication passage inlet 441a
and the communication passage outlet 441b and is joined to the
downstream side lower tank 411 and the upstream side lower tank
421. The dome member 44b is joined to the planar member 441 and has
a projecting portion 44a, which projects in the X-direction
(lateral direction) away from the planar member 441 to define a
predetermined space therein and thereby to define the second
communication passage 43.
[0075] The communication passage forming member 44 may be assembled
as follows. First, the planar member 441 is joined to the
downstream side lower tank 411 and the upstream side lower tank 421
by, for example, brazing, such that the communication passage inlet
441a and the communication passage outlet 441b are respectively
aligned with a lateral side end opening 411a of the downstream side
lower tank 411 and a lateral side end opening 421a of the upstream
side lower tank 421. Then, the dome member 44b is joined to the
planar member 441 by, for example, brazing, such that the
communication passage inlet 441a and the communication passage
outlet 441b are opposed to a recess, which is formed inside of the
projecting portion 44a.
[0076] With the above construction, a portion of the refrigerant in
the furthermost downstream side lower tank 411 is supplied into the
second communication passage 43 through the communication passage
inlet 441a and flows toward the upstream side of the air flow to
enter the furthermost upstream side lower tank 421 through the
communication passage outlet 441b. Then, this refrigerant in the
furthermost upstream side lower tank 421 flows upwardly through the
furthermost upstream side flow passage row 220 and then flows into
the furthermost upstream side upper tank 321, which is opposite
from the furthermost upstream side lower tank 421 in the
top-to-bottom direction of the core 100. The remaining refrigerant
(the rest of the refrigerant) in the furthermost downstream side
lower tank 411 flows upwardly through the furthermost downstream
side flow passage row 210 and is supplied into the furthermost
downstream side upper tank 311, which is opposite from the
furthermost downstream side lower tank 411 in the top-to-bottom
direction of the core 100. Then, this refrigerant flows toward the
upstream side of the air flow and enters into the upstream side
upper tank 321 where this refrigerant is merged with the branched
portion of the refrigerant, which has passed through the second
communication passage 43.
[0077] Tube insertion inlets and side plate insertion inlets are
provided at generally equal pitches in the longitudinal direction
in a wall surface of each of the upper and lower header tanks 3, 4.
The longitudinal end portions of each tube 20 and the longitudinal
end portions of each side plate 28 are received into and are joined
to the corresponding tube insertion inlets and the corresponding
side plate insertion inlets by, for example, brazing. In this way,
the tubes 20 are communicated with the interior space of each of
the upper and lower header tanks 3, 4, and the longitudinal end
portions of each side plate 28 are supported by the upper and lower
header tanks 3, 4.
[0078] The refrigerant flow pattern in the evaporator 1 of the
present embodiment is constructed from three downstream side flow
passage rows and three upstream side flow passage rows. The three
downstream side flow passage rows include one downstream side flow
passage row 21b (the refrigerant upflow portion), one downstream
side flow passage row 21b (the refrigerant downflow portion) and
one furthermost downstream side flow passage row 210. The three
upstream side flow passage rows include one furthermost upstream
side flow passage row 220, one upstream side flow passage row 22b
(the refrigerant downflow portion) and one upstream side flow
passage row 22a (the refrigerant upflow portion).
[0079] In this instance, the number of the refrigerant flow paths
is counted in the following manner. Specifically, the refrigerant
flow in the furthermost downstream side flow passage row 210 and
refrigerant flow in the furthermost upstream side flow passage row
220 are collectively counted as one refrigerant flow path.
Furthermore, the number (two in this instance) of the other
downstream side flow passage rows 21a, 21b, which are other than
the furthermost downstream side flow passage row 210, and the
number (two in this instance) of the other upstream side flow
passage rows 22a, 22b, which are other than the furthermost
upstream side flow passage row 220, are also counted. Therefore,
the number of the refrigerant flow paths in the core 100 is five in
the present embodiment. Furthermore, the refrigerant flow pattern
in the evaporator 1 is expressed by the number of path(s) in the
downstream side flow passage rows 21, the number of path(s) in the
upstream side flow passage row 22 and the number of path(s) of the
full-path portion 200 (the portion where the branched flow of the
refrigerant, which is branched from the downstream side to the
upstream side, flows upwardly in the top-to-bottom direction of the
core 100). These numbers are written one after another according to
the flow order of the refrigerant in the evaporator 1 and are
thereby expressed as a 2-1-2 refrigerant flow pattern in this
instance.
[0080] Next, the flow of the refrigerant in the evaporator 1 will
be sequentially described. The refrigerant from the external
constituent component of the refrigeration cycle is supplied into
the downstream side lower tank 41, which is the space on the left
lateral side of the separator 41a (the side of the separator 41a,
which is opposite from the X-direction) through the upper flow
inlet 51 and the side flow passage 2. Then, the refrigerant flows
upwardly through the downstream side flow passage row 21a (the
first path). Next, the flow direction of this refrigerant is
reversed in the interior of the downstream side upper tank 31,
which is the space on the left lateral side of the separator 31a
(the side of the separator 31a, which is opposite from the
X-direction), and thereafter the refrigerant flows downwardly
through the downstream side flow passage row 21b (the second path).
Thereafter, this refrigerant is supplied into the interior of the
furthermost downstream side lower tank 411.
[0081] Then, a portion of the refrigerant in the downstream side
lower tank 411 is branched into the second communication passage
43. Then, in the second communication passage 43, the branched
portion of the refrigerant flows in the X-direction and then flows
toward the upstream side of the air flow (the side opposite from
the Z-direction), and thereafter the branched portion of the
refrigerant flows in the direction opposite from the X-direction
and is supplied into the upstream side lower tank 421. Thereafter,
this branched portion of the refrigerant flows upwardly through the
furthermost upstream side flow passage row 220 (the third path, the
full-path portion 200) into the upstream side upper tank 321.
[0082] In contrast, the remaining refrigerant (the rest of the
refrigerant) in the downstream side lower tank 411, which is other
than the branched portion of the refrigerant, flows upwardly
through the furthermost downstream side flow passage row 210 (the
third path, the full-path portion 200) and then flows from the
interior of the downstream side upper tank 311 toward the upstream
side of the air flow into the upstream side upper tank 321 through
the communication holes 300 in the first communication passage 33.
Then, this refrigerant is merged with the above branched portion of
the refrigerant, which is supplied through the furthermost upstream
side flow passage row 220 after flowing upwardly therethrough. That
is, the refrigerant in the furthermost downstream side flow passage
row 210 and the refrigerant in the furthermost upstream side flow
passage row 220 flow upwardly parallel to one another.
[0083] The flow direction of the merged refrigerant, which is
merged in the interior of the upstream side upper tank 321, is
reversed, and this refrigerant flows downwardly through the
upstream side flow passage row 22b (the fourth path). Then, the
flow direction of this refrigerant is reversed once again in the
upstream side lower tank 42, and thereby the refrigerant flows
upwardly through the upstream side flow passage row 22a (the fifth
path). Thereafter, this refrigerant flows to the outside of the
core 100 from the upstream side upper tank 32 through the flow
outlet 52.
[0084] Normally, the evaporator has the function of cooling the air
by taking the heat of vaporization from the air at the time of
vaporization of the liquid phase refrigerant (hereinafter, referred
to as the liquid refrigerant). Therefore, in the evaporator, the
refrigerant is in the two-phase (gas phase and liquid phase) state.
In the operating state of the evaporator, a gas-liquid density
ratio is about 80 to 95 times (i.e., liquid phase density:gas phase
density=80-95:1) in the case of the R134a refrigerant and is about
8 to 9 times in the case of the carbon dioxide refrigerant.
Therefore, the gas/liquid separation substantially occurs.
Furthermore, an enlarged flow passage cross sectional area is
provided at the tank as a refrigerant pressure loss reducing means.
However, when this measure is taken, the refrigerant flow velocity
at the tank is reduced, so that the gas/liquid separation is
further promoted, thereby causing a reduced performance.
Furthermore, there is a strong market demand for an evaporator
having a simple structure, in which the refrigerant flow passage is
simplified.
[0085] The evaporator of the present embodiment addresses the above
demand and has the following structure. The evaporator has the flow
inlet 51 and the flow outlet 52, which are provided at the one
lateral end portion of the evaporator on the same lateral side. The
second communication passage 43 (the lower communication passage)
is provided to the opposite lateral side of the core 100, which is
opposite from the side where the flow inlet 51 and the flow outlet
52 are located, to communicate between the interior of the
downstream side lower tank 411, which is connected to the
furthermost downstream side flow passage row 210 that is
furthermost from the flow inlet 51, and the interior of the
upstream side lower tank 421, which is connected to the furthermost
upstream side flow passage row 220 that is furthermost from the
flow outlet 52. The second communication passage 43 conducts the
portion of the refrigerant in the furthermost downstream side lower
tank 411, which is furthermost from the flow inlet 51, into the
upstream side lower tank 421 to supply the refrigerant into the
furthermost upstream side flow passage row 220. The second
communication passage 43 is placed at the location that projects
laterally or vertically (or in the top-to-bottom direction) from
the body of the core 100.
[0086] The refrigerant, which has passed through the multiple
downstream side flow passage rows 21 upwardly and downwardly
multiple turns in the S-shaped path, gets the inertial force and
reaches the furthermost downstream side lower tank 411. With the
above structure, the refrigerant flows through the second
communication passage 43 (the lower communication passage), which
is placed at the location that projects laterally from the body of
the core 100. Thus, the refrigerant can get the additional inertial
force, and thereby the refrigerant in the downstream side lower
tank 411 can be supplied in the greater amount to the furthermost
upstream side flow passage row 220. The above effect is more
prominent in the evaporator that has the thickness (the thickness
in the air flow direction) T of the core 100, which is equal to or
less than 70 mm.
[0087] The heat exchanger, which has the above structure, can
reduce or alleviate the transitional period temperature
distribution (transitional period temperature difference) between
an on-time and an off-time of the compressor. When this heat
exchanger is applied as the evaporator of the vehicle air
conditioning system, the comfortableness of the occupant of the
vehicle can be improved. Furthermore, the anti-frost performance of
the evaporator can be improved to improve the cooling performance
of the air conditioning system.
[0088] Furthermore, in the case where the refrigerant flow quantity
is relatively small at the time of, for example, a low load
operation, even in the upstream side flow passage, the flow of the
refrigerant, which has passed through the second communication
passage 43, is biased toward the downstream side of the air flow.
Therefore, when the entire furthermost part of the core 100 is
viewed, the condition of the refrigerant inflow in the core width
direction is reversed between the downstream side part of the
furthermost portion of the core 100 and the upstream side part of
the furthermost portion of the core 100, so that they can be
compensated with each other to implement the self adjusting
function.
[0089] Furthermore, in the case of the evaporator 1 where the flow
inlet 51 and the flow outlet 52 are provided together at the one
lateral side of the core 100 in the lateral direction of the core
100, the adjacent area of the upstream side flow passage row 22,
which is adjacent to the flow outlet 52, serves as a refrigerant
superheating area. Therefore, the portion of the core 100, in which
the refrigerant tends to be stagnated, is the furthermost
downstream side flow passage row, which is placed furthermost from
the flow inlet 51 and the flow outlet 52 and contacts with the
cooler air. In the evaporator 1 of the present embodiment, the
occurrence of the stagnation of the liquid refrigerant can be
reduced or alleviated.
[0090] Furthermore, the evaporator 1 has the second communication
passage 43 (the lower communication passage), which communicates
between the interior of the furthermost downstream side lower tank
411 and the interior of the furthermost upstream side lower tank
421, and the first communication passage 33 (the upper
communication passage), which communicates between the interior of
the furthermost downstream side upper tank 311 and the interior of
the furthermost upstream side upper tank 321. In this structure,
the remaining refrigerant in the furthermost downstream side lower
tank 411 flows upwardly through the furthermost downstream side
flow passage row 210 and then flows toward the upstream side of the
air flow through the first communication passage 33 and finally
into the upstream side upper tank 321 where the remaining
refrigerant is merged with the branched refrigerant, which has
flown upwardly through the furthermost upstream side flow passage
row 220 upon passing through the second communication passage 43
(the lower communication passage).
[0091] With the above structure, it is possible to limit the flow
tendency of the refrigerant in the furthermost downstream side
lower tank 411 into the downstream side flow passage row 210.
Thereby, it is possible to supply the greater amount of the
refrigerant into the upstream side flow passage row 220.
[0092] The refrigerant pressure loss of the evaporator 1 gets
bigger toward the evaporator outlet side. Therefore, it is
desirable to have the refrigerant, which has completed the heat
exchange, at the location adjacent to the flow outlet 52. Since the
flow outlet 52 is provided to the end portion of the upstream side
upper tank 32, it is desirable that the upstream side flow passage
row 22a, which conducts the final refrigerant flow in the upstream
side flow passage rows 22, is the refrigerant upflow portion.
Furthermore, since the furthermost upstream side flow passage row
220 (the third path), which is furthermost from the flow outlet 52,
is also the refrigerant upflow portion, it is desirable that the
upstream side flow passage row 22b (the fourth path) is the
refrigerant downflow portion.
Second Embodiment
[0093] The evaporator 1 according to a second embodiment of the
present invention is a modification of the first embodiment and
will be described with reference to FIGS. 5 and 6. FIG. 5 is a
schematic diagram showing the structure of the evaporator 1 and the
flow of refrigerant therein according to the present embodiment.
FIG. 6 is a schematic diagram showing a positional relationship of
the communication passage inlet 441a and the communication passage
outlet 441b relative to the downstream side flow passage row 210
and the upstream side flow passage row 220.
[0094] In the present embodiment, the first communication passage
33 (the upper communication passage) of the evaporator 1 of FIG. 3
is modified and is thereby placed at a location, which projects
laterally from the body of the core 100 in the X-direction (the
lateral direction) in a manner similar to the second communication
passage 43. Other than this point, the evaporator of the present
embodiment is the same as the evaporator 1 of FIG. 3 and provides
the same effects and the same advantages as those of the evaporator
1 of FIG. 3.
[0095] The first communication passage 33 is formed in an interior
of a communication passage forming member 34. A communication
passage inlet 341a of the first communication passage 33, through
which the refrigerant is supplied into the first communication
passage 33, includes one or more holes that extend through in the
X-direction (the lateral direction) to communicate between the
interior of the furthermost downstream side upper tank 311 and the
interior of the communication passage forming member 34. A
communication passage outlet 341b of the first communication
passage 33, through which the refrigerant is outputted from the
first communication passage 33, includes one or more holes that
extend through in the X-direction (the lateral direction) to
communicate between the interior of the communication passage
forming member 34 and the interior of the furthermost upstream side
upper tank 321.
[0096] The communication passage forming member 34 is a separate
component, which is formed separately from the downstream side
upper tank 311 and the upstream side upper tank 321 and is
integrally fixed to the downstream side upper tank 311 and the
upstream side upper tank 321 by, for example, brazing. The
communication passage forming member 34 is placed at the location,
which projects laterally from the body of the core 100. In the
present embodiment, the communication passage forming member 34 is
configured into a box shape that projects laterally from the
furthermost downstream side upper tank 311. Furthermore, the
communication passage forming member 34 is made of the material
that is similar to or the same as that of the furthermost
downstream side upper tank 311.
[0097] As shown in FIG. 6, the communication passage inlet 441a (a
refrigerant inflow opening) is opened to the interior of the
furthermost downstream side lower tank 411 and is located on a
lower side of lower end openings 210a of the tubes 20a of the
furthermost downstream side flow passage row 210 in the vertical
direction (gravitational direction).
[0098] For the comparative purpose, it is now assumed that the
refrigerant in the furthermost flow passage rows 210, 220 form the
upflow, and the refrigerant inflow opening of the second
communication passage opens in the furthermost downstream side
lower tank only on an upper side of the lower end openings of the
tubes of the furthermost flow passage rows 210, 220 in the vertical
direction. In such a case, the lower end openings of the tubes of
the furthermost flow passage row are closer to the liquid surface
of the refrigerant in the tank in comparison to the refrigerant
inflow opening of the second communication passage, so that the
refrigerant tends to flow into the furthermost downstream side flow
passage row 210, and thereby the refrigerant cannot easily flow
into the first communication passage through the refrigerant inflow
opening. With the above structure of the present embodiment, it is
possible to limit the flow tendency of the refrigerant in the
furthermost downstream side lower tank into the downstream side
flow passage row, and thereby it is possible to supply the greater
amount of the refrigerant into the upstream side flow passage row.
As a result, the heat exchange performance of the evaporator can be
improved.
[0099] Furthermore, it is desirable that an upper end of the
opening of the communication passage inlet 441a (the refrigerant
inflow opening) is located on the lower side of the lower end
openings 210a of the tubes 20a of the furthermost downstream side
flow passage row 210.
Third Embodiment
[0100] The evaporator 1 according to a third embodiment of the
present invention is a modification of the evaporator 1 of the
first embodiment and will be described with reference to FIG. 7.
FIG. 7 is a schematic diagram showing the structure of the
evaporator 1 and the flow of refrigerant therein according to the
present embodiment.
[0101] The present embodiment differs from that of FIG. 3 such that
the second communication passage 43 (the lower communication
passage) of the evaporator 1 of FIG. 3 is modified and is thereby
placed at a location, which projects downwardly from the body of
the core 100 in the vertical direction (the direction opposite from
the Y-direction). Other than this point, the evaporator of the
present embodiment is the same as the evaporator 1 of FIG. 3 and
provides the same effects and the same advantages as those of the
evaporator 1 of FIG. 3.
[0102] In the case of the present embodiment, the communication
passage forming member 44A, which forms the second communication
passage 43, is provided integrally with the lower surfaces of the
furthermost downstream side lower tank 411 and the furthermost
upstream side lower tank 421, which are located at the lateral end
portion of the core 100 in the X-direction. The communication
passage forming member 44A is placed inward of two lateral ends of
the core 100 in the lateral direction of the core 100. In this way,
a dead space is reduced to effectively use the installation space
for placing the heat exchanger, and the size of the core 100 in the
width direction can be increased. Thus, it is possible to implement
the design that improves the effective heat exchange surface area
of the core 100.
[0103] The communication passage inlet 441a of the second
communication passage 43, through which the refrigerant is supplied
into the second communication passage 43, includes one or more
holes that extend through a lower surface of the furthermost
downstream side lower tank 411 and an upper surface of the
communication passage forming member 44A in the Y-direction (the
vertical direction) to communicate between the interior of the
furthermost downstream side lower tank 411 and the interior of the
communication passage forming member 44A. The communication passage
outlet 441b of the second communication passage 43, through which
the refrigerant is outputted from the second communication passage
43, includes one or more holes that extend through a lower surface
of the furthermost upstream side lower tank 421 and an upper
surface of the communication passage forming member 44A in the
Y-direction (the vertical direction) to communicate between the
interior of the communication passage forming member 44A and the
interior of the furthermost downstream side lower tank 421.
[0104] The communication passage forming member 44A is a separate
component, which is formed separately from the downstream side
lower tank 411 and the upstream side lower tank 421 and is
integrally fixed to the downstream side lower tank 411 and the
upstream side lower tank 421 by, for example, brazing.
[0105] In the evaporator of the present embodiment, the second
communication passage 43 is placed at the location, which projects
downwardly from the body of the core 100 in the vertical direction
(or in the top-to-bottom direction of the core 100). The
refrigerant, which has passed through the multiple downstream side
flow passage rows 21 upwardly and downwardly multiple turns in the
S-shaped path, gets the inertial force and reaches the furthermost
downstream side lower tank 411. This refrigerant flows through the
second communication passage 43 (the lower communication passage),
which is placed at the location that projects downwardly from the
body of the core 100 in the vertical direction. Thus, the
refrigerant can get the additional inertial force by the gravity to
promote the vertically downward flow of the refrigerant, and
thereby the refrigerant in the downstream side lower tank 411 can
be supplied in the greater amount to the furthermost upstream side
flow passage row 220.
Fourth Embodiment
[0106] The evaporator 1 according to a fourth embodiment of the
present invention is a modification of the evaporator 1 of the
first embodiment and will be described with reference to FIG. 8.
FIG. 8 is a schematic diagram showing the structure of the
evaporator and the flow of refrigerant therein according to the
present embodiment.
[0107] The evaporator of the present embodiment differs from the
evaporator 1 of FIG. 3 with respect to the following points. That
is, the refrigerant flow pattern is different from that of FIG. 3,
and the flow of the refrigerant in the furthermost flow passage row
is the downflow. Furthermore, the first communication passage 33A
is placed at a location, which projects laterally from the body of
the core 101. In FIG. 8, components similar to those of FIG. 3 will
be indicated by the same reference numerals. Other than this point,
the evaporator of the present embodiment is the same as the
evaporator 1 of FIG. 3 and provides the same effects and the same
advantages as those of the evaporator 1 of FIG. 3.
[0108] The refrigerant flow pattern in the evaporator 1 of the
present embodiment is constructed from two downstream side flow
passage rows and two upstream side flow passage rows. The two
downstream side flow passage rows include one downstream side flow
passage row 21a (the refrigerant upflow portion) and one
furthermost downstream side flow passage row 211 (the refrigerant
downflow portion). The two upstream side flow passage rows include
one furthermost upstream side flow passage row 221 (the refrigerant
downflow portion) and one upstream side flow passage row 22a (the
refrigerant upflow portion).
[0109] In this instance, the number of the refrigerant flow paths
is three. Furthermore, the refrigerant flow pattern in the
evaporator 1 is expressed by the number of path(s) in the
downstream side flow passage rows 21, the number of path(s) in the
upstream side flow passage row 22 and the number of path(s) of the
full-path portion 201 (the portion where the branched flow of the
refrigerant from the downstream side to the upstream side flows
downwardly). These numbers are written one after another according
to the flow order of the refrigerant in the evaporator 1 and are
thereby expressed as a 1-1-1 refrigerant flow pattern in this
instance.
[0110] The first communication passage 33A is formed in the
interior of the communication passage forming member 34A. A
communication passage inlet 341a of the first communication passage
33A, through which the refrigerant is supplied into the first
communication passage 33A, includes one or more holes that extend
through in the X-direction (the lateral direction) to communicate
between the interior of the furthermost downstream side upper tank
311 and the interior of the communication passage forming member
34A. A communication passage outlet 341b of the first communication
passage 33A, through which the refrigerant is outputted from the
first communication passage 33A, includes one or more holes that
extend through in the X-direction (the lateral direction) to
communicate between the interior of the communication passage
forming member 34A and the interior of the furthermost upstream
side upper tank 321.
[0111] The communication passage forming member 34A is a separate
component, which is formed separately from the downstream side
upper tank 311 and the upstream side upper tank 321 and is
integrally fixed to the downstream side upper tank 311 and the
upstream side upper tank 321 by, for example, brazing. The
communication passage forming member 34A is placed at the location,
which projects laterally from the body of the core 101. In the
present embodiment, the communication passage forming member 34A is
configured into a box shape that projects laterally from the
furthermost downstream side upper tank 311. Furthermore, the
communication passage forming member 34A is made of the material
that is similar to or the same as that of the furthermost
downstream side upper tank 311. In the evaporator of the present
embodiment, a separator is not provided in the downstream side
upper tank 31. Therefore, the furthermost downstream side upper
tank 311 is the downstream side upper tank 31 itself.
[0112] With the above construction, a portion of the refrigerant in
the furthermost downstream side upper tank 311 is supplied into the
first communication passage 33A through the communication passage
inlet 341a and flows toward the upstream side of the air flow to
enter the furthermost upstream side upper tank 321 through the
communication passage outlet 341b. Then, this refrigerant in the
furthermost upstream side upper tank 321 flows downwardly through
the furthermost upstream side flow passage row 221 and then flows
into the furthermost upstream side lower tank 421, which is
opposite from the furthermost upstream side upper tank 321 in the
top-to-bottom direction of the core. The remaining refrigerant in
the furthermost downstream side upper tank 311 flows downwardly
through the furthermost downstream side flow passage row 211 and is
supplied into the furthermost downstream side lower tank 411, which
is opposite from the furthermost downstream side upper tank 311 in
the top-to-bottom direction of the core. Then, this refrigerant
flows toward the upstream side of the air flow and enters into the
upstream side lower tank 421 where this refrigerant is merged with
the branched portion of the refrigerant, which has passed through
the first communication passage 33A.
[0113] Next, the flow of the refrigerant in the evaporator will be
sequentially described. The refrigerant from the external
constituent component of the refrigeration cycle is supplied into
the downstream side lower tank 41, which is the space on the left
lateral side of the separator 41a (the side of the separator 41a,
which is opposite from the X-direction) through the upper flow
inlet 51 and the side flow passage 2. Then, the refrigerant flows
upwardly through the downstream side flow passage row 21a (the
first path) and is supplied into the downstream side upper tank
311.
[0114] Then, a portion of the refrigerant in the downstream side
upper tank 311 is branched into the first communication passage
33A. Then, in the first communication passage 33A, the branched
portion of the refrigerant flows in the X-direction and then flows
toward the upstream side of the air flow (the side opposite from
the Z-direction), and thereafter the branched portion of the
refrigerant flows in the direction opposite from the X-direction
and is supplied into the upstream side upper tank 321. Thereafter,
this branched portion of the refrigerant flows downwardly through
the furthermost upstream side flow passage row 221 (the second
path, the full-path portion 201) into the upstream side lower tank
421.
[0115] In contrast, the remaining refrigerant in the downstream
side upper tank 311, which is other than the branched portion of
the refrigerant, flows downwardly through the furthermost
downstream side flow passage row 211 (the second path, the
full-path portion 201) and then flows from the interior of the
downstream side lower tank 411 toward the upstream side of the air
flow into the upstream side lower tank 421 through the
communication holes 400 in the second communication passage 43.
Then, this refrigerant is merged with the above branched portion of
the refrigerant, which is supplied through the furthermost upstream
side flow passage row 221 after flowing downwardly therethrough, in
the upstream side lower tank 421. That is, the refrigerant in the
furthermost downstream side flow passage row 211 and the
refrigerant in the furthermost upstream side flow passage row 221
flow downwardly parallel to one another. The flow direction of the
merged refrigerant, which is merged in the upstream side lower tank
421, is reversed, and this refrigerant flows upwardly through the
upstream side flow passage row 22a (the third path). Thereafter,
this refrigerant flows to the outside of the core from the upstream
side upper tank 32 through the flow outlet 52.
[0116] In the evaporator of the present embodiment, the first
communication passage 33A is placed at the location, which projects
laterally from the body of the core 101. The refrigerant, which has
passed through the multiple downstream side flow passage rows 21
upwardly and downwardly multiple turns in the S-shaped path, gets
the inertial force and reaches the furthermost downstream side
upper tank 311. This refrigerant flows through the first
communication passage 33A (the upper communication passage), which
is placed at the location that projects laterally from the body of
the core 101. Thus, the refrigerant can get the additional inertial
force to promote the flow of the refrigerant toward the upstream
side of the air flow, and thereby the refrigerant in the downstream
side upper tank 311 can be supplied in the greater amount to the
furthermost upstream side flow passage row 221.
Fifth Embodiment
[0117] The evaporator according to a fifth embodiment of the
present invention is a modification of the evaporator of the fourth
embodiment and will be described with reference to FIG. 9. FIG. 9
is a schematic diagram showing the structure of the evaporator 1
and the flow of refrigerant therein according to the present
embodiment. In the present embodiment, the second communication
passage 43 (the lower communication passage) of the evaporator is
modified from that of the evaporator 1 of FIG. 8 in a manner
similar to the first communication passage 33A. Thus, the second
communication passage 43 is placed at a location, which projects
laterally from the body of the core 101 in the X-direction (the
lateral direction). Other than this point, the evaporator of the
present embodiment is the same as the evaporator 1 of FIG. 8 and
provides the same effects and the same advantages as those of the
evaporator 1 of FIG. 8.
Sixth Embodiment
[0118] The evaporator according to a sixth embodiment of the
present invention is a modification of the evaporator of the fifth
embodiment and will be described with reference to FIGS. 10 and 11.
FIG. 10 is a schematic diagram showing the structure of the
evaporator and the flow of refrigerant therein according to the
present embodiment. FIG. 11 is a schematic diagram showing a
positional relationship of the communication passage inlet 341a and
the communication passage outlet 341b relative to the downstream
side flow passage row 211 and the upstream side flow passage row
221.
[0119] The evaporator of the present embodiment is different from
the evaporator of FIG. 9 with respect to the refrigerant flow
pattern, the structure of the core 102, the number of the
downstream side flow passage rows and the number of the upstream
side flow passage rows. In FIG. 10, components similar to those of
FIG. 9 will be indicated by the same reference numerals. Other than
the above points, the evaporator of the present embodiment is the
same as the evaporator of FIG. 9 and provides the same effects and
the same advantages as those of the evaporator of FIG. 9.
[0120] The refrigerant flow pattern in the evaporator of the
present embodiment is constructed from three downstream side flow
passage rows and two upstream side flow passage rows. The three
downstream side flow passage rows include one downstream side flow
passage row 21b (the refrigerant downflow portion), one downstream
side flow passage row 21a (the refrigerant upflow portion) and one
furthermost downstream side flow passage row 211 (the refrigerant
downflow portion). The two upstream side flow passage rows include
one furthermost upstream side flow passage row 221 (the refrigerant
downflow portion) and one upstream side flow passage row 22a (the
refrigerant upflow portion). Furthermore, the evaporator of the
present embodiment does not have the side flow passage.
[0121] In this instance, the number of the refrigerant flow paths
is four. Furthermore, the refrigerant flow pattern in the
evaporator is expressed by the number of path(s) in the downstream
side flow passage rows 21, the number of path(s) in the upstream
side flow passage row 22 and the number of path(s) of the full-path
portion 201 (the portion where the branched flow of the refrigerant
from the downstream side to the upstream side flows downwardly).
These numbers are written one after another according to the flow
order of the refrigerant in the evaporator 1 and are thereby
expressed as a 2-1-1 refrigerant flow pattern in this instance.
[0122] With the above construction, a portion of the refrigerant in
the furthermost downstream side upper tank 311 is supplied into the
first communication passage 33A through the communication passage
inlet 341a and flows toward the upstream side of the air flow to
enter the furthermost upstream side upper tank 321 through the
communication passage outlet 341b. Then, this refrigerant in the
furthermost upstream side upper tank 321 flows downwardly through
the furthermost upstream side flow passage row 221 and then flows
into the furthermost upstream side lower tank 421, which is
opposite from the furthermost upstream side upper tank 321 in the
top-to-bottom direction of the core. The remaining refrigerant in
the furthermost downstream side upper tank 311 flows downwardly
through the furthermost downstream side flow passage row 211 and is
supplied into the furthermost downstream side lower tank 411, which
is opposite from the furthermost downstream side upper tank 311 in
the top-to-bottom direction. Thereafter, this refrigerant flows
into the second communication passage 43 through the communication
passage inlet 441a and flows toward the upstream side of the air
flow in the second communication passage 43. Then, this refrigerant
flows into the upstream side lower tank 421 through the
communication passage outlet 441b. In the upstream side lower tank
421, this refrigerant is merged with the branched portion of the
refrigerant, which has passed through the first communication
passage 33A.
[0123] Next, the flow of the refrigerant in the evaporator will be
sequentially described. The refrigerant from the external
constituent component of the refrigeration cycle is supplied into
the downstream side upper tank 31, which is the space on the left
lateral side of the separator 31a (the side of the separator 31a,
which is opposite from the X-direction) through the upper flow
inlet 51. Then, the refrigerant flows downwardly through the
downstream side flow passage row 21b (the first path). Next, the
flow direction of this refrigerant is reversed in the interior of
the downstream side lower tank 41, which is the space on the left
lateral side of the separator 41a (the side of the separator 41a,
which is opposite from the X-direction), and thereafter the
refrigerant flows upwardly through the downstream side flow passage
row 21a (the second path) and is supplied into the interior of the
furthermost downstream side upper tank 311.
[0124] Then, a portion of the refrigerant in the downstream side
upper tank 311 is branched into the first communication passage
33A. Then, in the first communication passage 33A, the branched
portion of the refrigerant flows in the X-direction and then flows
toward the upstream side of the air flow (the side opposite from
the Z-direction), and thereafter the branched portion of the
refrigerant flows in the direction opposite from the X-direction
and is supplied into the upstream side upper tank 321. Thereafter,
this branched portion of the refrigerant flows downwardly through
the furthermost upstream side flow passage row 221 (the third path,
the full-path portion 201) into the upstream side lower tank
421.
[0125] In contrast, the remaining refrigerant in the downstream
side upper tank 311, which is other than the branched portion of
the refrigerant, flows downwardly through the furthermost
downstream side flow passage row 211 (the third path, the full-path
portion 201) and then flows from the interior of the downstream
side lower tank 411 into the second communication passage 43. Then,
in the second communication passage 43, the refrigerant flows in
the X-direction and then flows toward the upstream side of the air
flow (the side opposite from the Z-direction), and thereafter the
refrigerant flows in the direction opposite from the X-direction
and is supplied into the upstream side lower tank 421 where this
refrigerant is merged with the branched portion of the refrigerant,
which has flown downwardly through the furthermost upstream side
flow passage row 221. That is, the refrigerant in the furthermost
downstream side flow passage row 211 and the refrigerant in the
furthermost upstream side flow passage row 221 flow downwardly
parallel to one another. The flow direction of the merged
refrigerant, which is merged in the upstream side lower tank 421,
is reversed, and this refrigerant flows upwardly through the
upstream side flow passage row 22a (the fourth path). Thereafter,
this refrigerant flows to the outside of the core from the upstream
side upper tank 32 through the flow outlet 52.
[0126] As shown in FIG. 11, the communication passage inlet 341a
(the refrigerant inflow opening) is opened to the interior of the
furthermost downstream side upper tank 311 and is located on an
upper side of upper end openings 211a of the tubes 20a of the
furthermost downstream side flow passage row 211 in the vertical
direction.
[0127] For the comparative purpose, it is now assumed that the
refrigerant in the furthermost flow passage row forms the downflow,
and the refrigerant inflow opening of the first communication
passage opens in the furthermost downstream side upper tank only on
a lower side of the upper end openings of the tubes of the
furthermost flow passage row in the vertical direction. In such a
case, the refrigerant tends to flow into the furthermost downstream
side flow passage row of the core, and thereby the refrigerant
cannot easily flow into the first communication passage through the
refrigerant inflow opening. With the above structure of the present
embodiment, it is possible to limit the flow tendency of the
refrigerant in the furthermost downstream side upper tank into the
downstream side flow passage row, and thereby it is possible to
guide the refrigerant into the communication passage inlet 341a
(the refrigerant inflow opening) and thereby to supply the greater
amount of the refrigerant into the upstream side flow passage row.
As a result, the heat exchange performance of the evaporator can be
improved.
[0128] Furthermore, it is desirable that the lower end of the
opening of the communication passage inlet 341a (the refrigerant
inflow opening) is located on the upper side of the upper end
openings 211a of the tubes 20a of the furthermost downstream side
flow passage row 211.
[0129] Furthermore, in the evaporator of the present embodiment,
the number of the downstream side flow passage rows 21 and the
number of the upstream side flow passage rows 22 are set as
follows. That is, the number of the other downstream side flow
passage rows 21a, 21b other than the furthermost downstream side
flow passage row 211 is two, and the number of the other upstream
side flow passage row 22a other than the furthermost upstream side
flow passage row 221 is one. Therefore, the number of the other
downstream side flow passage rows 21a, 21b other than the
furthermost downstream side flow passage row 211 is greater than
the number of the other upstream side flow passage row 22a other
than the furthermost upstream side flow passage row 221. With the
above structure, in the case of the heat exchanger, in which the
dryness of the refrigerant is larger on the downstream side in
comparison to the upstream side, it is possible to reduce the
pressure loss.
Seventh Embodiment
[0130] The evaporator according to a seventh embodiment of the
present invention is a modification of the evaporator of the sixth
embodiment and will be described with reference to FIGS. 12 and 13.
FIG. 12 is a schematic diagram showing the structure of the
evaporator and the flow of refrigerant therein according to the
present embodiment. FIG. 13 is a schematic diagram showing the
positional relationship of the communication holes 300 relative to
the downstream side flow passage row 211 and the upstream side flow
passage row 221. Although the downstream side flow passage row 211
is not shown in FIG. 13, it should be understood that the
downstream side flow passage row 211 is placed at the same position
in the Y-direction (the same vertical position), which is the same
as that of the upstream side flow passage row 221.
[0131] The evaporator of the present embodiment is the same as the
evaporator of FIG. 10 with respect to the refrigerant flow pattern
and the structure of the core 102 except that the communication
passage forming members 34A, 44A are not provided separately from
the rest of the core 102 to project laterally. In FIG. 12,
components similar to those of FIG. 10 will be indicated by the
same reference numerals. Other than the above point, the evaporator
of the present embodiment is the same as the evaporator of FIG. 10
and provides the same effects and the same advantages as those of
the evaporator of FIG. 10.
[0132] With the above construction, a portion of the refrigerant in
the furthermost downstream side upper tank 311 flows through the
communication holes 300 in the first communication passage 33
toward the upstream side of the air flow and is supplied into the
upstream side upper tank 321. Thereafter, this refrigerant flows
downwardly through the furthermost upstream side flow passage row
221 and is supplied into the upstream side lower tank 421, which is
opposite from the furthermost upstream side upper tank 321 in the
top-to-bottom direction of the core. The communication holes 300
also serve as a branching passage, which is provided between the
furthermost downstream side upper tank 311 and the furthermost
upstream side upper tank 321, so that a portion of the refrigerant
in the furthermost downstream side upper tank 311 flows toward the
upstream side of the air flow and is supplied into the upstream
side upper tank 321 through this branching passage.
[0133] In contrast, the remaining refrigerant in the furthermost
downstream side upper tank 311 flows downwardly through the
furthermost downstream side flow passage row 211 and is supplied
into the furthermost downstream side lower tank 411, which is
opposite from the furthermost downstream side upper tank 311. Then,
this refrigerant flows toward the upstream side of the air flow
through the communication holes 400 in the second communication
passage 43 and is supplied into the upstream side lower tank 421
where this refrigerant is merged with the branched portion of the
refrigerant, which has passed through the first communication
passage 33. The second communication passage 43, which includes the
communication holes 400, also serves as a merging passage, which is
provided between the furthermost downstream side lower tank 411 and
the furthermost upstream side lower tank 421, so that the remaining
refrigerant in the furthermost downstream side lower tank 411 flows
toward the upstream side of the air flow and is supplied into the
upstream side lower tank 421 through the communication holes 400 in
the second communication passage 43 to merge with the branched
portion of the refrigerant at the interior of the upstream side
lower tank 421.
[0134] The communication holes 300 are opened to the interior of
the furthermost downstream side upper tank 311, and the openings of
the communication holes 300 are placed on an upper side of the
upper end openings 211a of the tubes 20a of the furthermost
downstream side flow passage row 211 and the upper end openings
221a of the tubes 20b of the furthermost upstream side flow passage
row 221 in the vertical direction.
[0135] For the comparative purpose, it is now assumed that the
refrigerant in the furthermost flow passage row forms the downflow,
and the communication holes in the interior of the furthermost
downstream side upper tank, which are communicated with the
interior of the upstream side upper tank, open only on a lower side
of the upper end openings of the tubes of the furthermost flow
passage row in the vertical direction. In such a case, the
refrigerant tends to flow into the furthermost downstream side flow
passage row of the core. With the above structure of the present
embodiment, it is possible to limit the flow tendency of the
refrigerant in the furthermost downstream side upper tank into the
downstream side flow passage row, and thereby it is possible to
supply the greater amount of the refrigerant into the upstream side
flow passage row. As a result, the heat exchange performance of the
evaporator can be improved.
[0136] Furthermore, it is desirable that the lower ends of the
openings of the communication holes 300 are located on the upper
side of the upper end openings 211a of the tubes 20a of the
furthermost downstream side flow passage row 211.
Eighth Embodiment
[0137] The evaporator according to an eighth embodiment of the
present invention is a modification of the evaporator of FIG. 3 of
the first embodiment and will be described with reference to FIGS.
14 and 15. FIG. 14 is a schematic diagram showing the structure of
the evaporator and the flow of refrigerant therein according to the
present embodiment. FIG. 15 is a schematic diagram showing the
positional relationship of the communication holes 400 relative to
the downstream side flow passage row 210 and the upstream side flow
passage row 220. Although the downstream side flow passage row 210
is not shown in FIG. 15, it should be understood that the
downstream side flow passage row 210 is placed at the same position
in the Y-direction (the same vertical position), which is the same
as that of the upstream side flow passage row 220.
[0138] The evaporator of the present embodiment is the same as the
evaporator of FIG. 3 with respect to the refrigerant flow pattern
and the structure of the core except that the communication passage
forming member 44 is not provided separately from the rest of the
core to project laterally. Here, the second communication passage
43 is formed between the interior of the downstream side lower tank
411 and the interior of the upstream side lower tank 421. In FIG.
14, components similar to those of FIG. 3 will be indicated by the
same reference numerals. Other than the above point, the evaporator
of the present embodiment is the same as the evaporator of FIG. 3
and provides the same effects and the same advantages as those of
the evaporator of FIG. 3.
[0139] With the above construction, a portion of the refrigerant in
the furthermost downstream side lower tank 411 flows through the
communication holes 400 in the second communication passage 43
toward the upstream side of the air flow and is supplied into the
upstream side lower tank 421. Thereafter, this refrigerant flows
upwardly through the furthermost upstream side flow passage row 220
and is supplied into the upstream side upper tank 321, which is
opposite from the furthermost upstream side lower tank 421 in the
top-to-bottom direction of the core. The second communication
passage 43, which includes the communication holes 400, also serves
as a branching passage, which is provided between the furthermost
downstream side lower tank 411 and the furthermost upstream side
lower tank 421, so that a portion of the refrigerant in the
furthermost downstream side lower tank 411 flows toward the
upstream side of the air flow and is supplied into the upstream
side lower tank 421 through the communication holes 400 in the
second communication passage 43.
[0140] In contrast, the remaining refrigerant in the furthermost
downstream side lower tank 411 flows upwardly through the
furthermost downstream side flow passage row 210 and is supplied
into the furthermost downstream side upper tank 311, which is
opposite from the furthermost downstream side lower tank 411 in the
top-to-bottom direction of the core. Then, this refrigerant flows
toward the upstream side of the air flow through the communication
holes 300 in the first communication passage 33 and is supplied
into the upstream side upper tank 321 where this refrigerant is
merged with the branched portion of the refrigerant, which has
passed through the second communication passage 43. The
communication holes 300 also serve as a merging passage, which is
provided between the furthermost downstream side upper tank 311 and
the furthermost upstream side upper tank 321, so that the remaining
refrigerant in the furthermost downstream side upper tank 311 flows
toward the upstream side of the air flow and is supplied into the
upstream side upper tank 321 through the communication holes 300 in
the first communication passage 33 to merge with the branched
portion of the refrigerant at the interior of the upstream side
upper tank 321.
[0141] The communication holes 400 are opened to the interior of
the furthermost downstream side lower tank 411, and the openings of
the communication holes 400 are placed on a lower side of the lower
end openings 210a of the tubes 20a of the furthermost downstream
side flow passage row 210 and the lower end openings 220a of the
tubes 20b of the furthermost upstream side flow passage row 220 in
the vertical direction.
[0142] For the comparative purpose, it is now assumed that the
refrigerant in the furthermost flow passage row forms the upflow,
and the communication holes in the interior of the furthermost
downstream side lower tank, which are communicated with the
interior of the upstream side lower tank, open only on an upper
side of the lower end openings of the tubes of the furthermost flow
passage row in the vertical direction. In such a case, the
refrigerant tends to flow into the furthermost downstream side flow
passage row of the core. With the above structure of the present
embodiment, it is possible to limit the flow tendency of the
refrigerant in the furthermost downstream side lower tank into the
downstream side flow passage row, and thereby it is possible to
supply the greater amount of the refrigerant into the upstream side
flow passage row. As a result, the heat exchange performance of the
evaporator can be improved.
[0143] Furthermore, it is desirable that the lower ends of the
openings of the communication holes 400 are located on the upper
side of the lower end openings 210a of the tubes 20a of the
furthermost downstream side flow passage row 210.
Ninth Embodiment
[0144] In a ninth embodiment of the present invention, a
modification (a case of six paths of refrigerant flow) of the
evaporator of the eighth embodiment will be described with
reference to FIG. 16. FIG. 16 is a schematic diagram showing the
structure of the evaporator and the flow of refrigerant therein in
the case where the number of the refrigerant flow paths is six.
[0145] The evaporator of the present embodiment is different from
the evaporator of FIG. 14 with respect to the refrigerant flow
pattern (six paths in this embodiment), the structure of the core
103 and the elimination of the side flow passage. Other than the
above points, the evaporator of the present embodiment is the same
as the evaporator of FIG. 14 and provides the same effects and the
same advantages as those of the evaporator of FIG. 14.
[0146] The refrigerant flow pattern in the evaporator of the
present embodiment is constructed from four downstream side flow
passage rows and three upstream side flow passage rows. The four
downstream side flow passage rows include two downstream side flow
passage rows 21b (the refrigerant downflow portion), one downstream
side flow passage row 21a (the refrigerant upflow portion) and one
furthermost downstream side flow passage row 210 (the refrigerant
upflow portion). The three upstream side flow passage rows include
one furthermost upstream side flow passage row 220 (the refrigerant
upflow portion), one upstream side flow passage row 22b (the
refrigerant downflow portion) and one upstream side flow passage
row 22a (the refrigerant upflow portion).
[0147] Therefore, the number of the refrigerant flow paths in the
core 103 is six in the present embodiment. Furthermore, the
refrigerant flow pattern in the evaporator is expressed by the
number of path(s) in the downstream side flow passage rows 21, the
number of path(s) in the upstream side flow passage row 22 and the
number of path(s) of the full-path portion 200 (the portion where
the branched flow of the refrigerant from the downstream side to
the upstream side flows upwardly). These numbers are written one
after another according to the flow order of the refrigerant in the
evaporator and are thereby expressed as a 3-1-2 refrigerant flow
pattern in this instance.
[0148] Next, the flow of the refrigerant in the evaporator will be
sequentially described. The refrigerant from the external
constituent component of the refrigeration cycle is supplied into
the downstream side upper tank 31, which is the space on the left
lateral side of the separator 31a (the side of the separator 31a,
which is opposite from the X-direction) through the upper flow
inlet 51. Then, the refrigerant flows downwardly through the
downstream side flow passage row 21b (the first path). Next, the
flow direction of this refrigerant is reversed in the interior of
the downstream side lower tank 41, which is the space on the left
lateral side of the separator 41a (the side of the separator 41a,
which is opposite from the X-direction), and thereafter the
refrigerant flows upwardly through the downstream side flow passage
row 21a (the second path). Thereafter, this refrigerant is supplied
into the downstream side upper tank 31, which is the space between
the separator 31b and the separator 31a, and the flow direction of
this refrigerant is reversed in the interior of the downstream side
upper tank 31. Then, this refrigerant flows downward through the
downstream side flow passage row 21b (the third path) and is
supplied into the furthermost downstream side lower tank 411.
[0149] A portion of the refrigerant in the downstream side lower
tank 411 is branched and flows toward the upstream side of the air
flow (the side opposite from the Z-direction) through the
communication holes 400 in the second communication passage 43.
Then, this refrigerant is supplied into the upstream side lower
tank 421. Then, this refrigerant flows upwardly through the
upstream side flow passage row 220 (the fourth path, the full-path
portion 200) and is supplied into the upstream side upper tank
321.
[0150] In contrast, the remaining refrigerant in the downstream
side lower tank 411, which is other than the branched portion of
the refrigerant, flows upwardly through the furthermost downstream
side flow passage row 210 (the fourth path, the full-path portion
200) and then flows from the interior of the downstream side upper
tank 311 toward the upstream side of the air flow into the upstream
side upper tank 321 through the communication holes 300 in the
first communication passage 33. Then, this refrigerant is merged
with the above branched portion of the refrigerant, which is
supplied through the furthermost upstream side flow passage row 220
after flowing upwardly therethrough. That is, the refrigerant in
the furthermost downstream side flow passage row 210 and the
refrigerant in the furthermost upstream side flow passage row 220
flow upwardly parallel to one another.
[0151] The flow direction of the merged refrigerant, which is
merged in the interior of the upstream side upper tank 321, is
reversed, and this refrigerant flows downwardly through the
upstream side flow passage row 22b (the fifth path). Then, the flow
direction of this refrigerant is reversed once again in the
upstream side lower tank 42, and thereby the refrigerant flows
upwardly through the upstream side flow passage row 22a (the sixth
path). Thereafter, this refrigerant flows to the outside of the
core from the upstream side upper tank 32 through the flow outlet
52.
[0152] Furthermore, in the evaporator of the present embodiment,
the number of the downstream side flow passage rows 21 and the
number of the upstream side flow passage rows 22 are set as
follows. That is, the number of the other downstream side flow
passage rows 21a, 21b other than the furthermost downstream side
flow passage row 210 is three, and the number of the other upstream
side flow passage row 22a, 22b other than the furthermost upstream
side flow passage row 220 is two. Therefore, the number of the
other downstream side flow passage rows 21a, 21b other than the
furthermost downstream side flow passage row 210 is greater than
the number of the other upstream side flow passage row 22a, 22b
other than the furthermost upstream side flow passage row 220. With
the above structure, in the case of the heat exchanger, in which
the dryness of the refrigerant is larger on the downstream side in
comparison to the upstream side, it is possible to reduce the
pressure loss.
Tenth Embodiment
[0153] In a tenth embodiment of the present invention, a
modification (a case of five paths of refrigerant flow) of the
evaporator of the ninth embodiment will be described with reference
to FIG. 17. FIG. 17 is a schematic diagram showing the structure of
the evaporator and the flow of refrigerant therein in the case
where the number of the refrigerant flow paths is five.
[0154] The evaporator of the present embodiment is different from
the evaporator of FIG. 16 with respect to the refrigerant flow
pattern (five paths in this embodiment) and the structure of the
core 104 and the location of the flow inlet 51 (the lower side in
this embodiment). Other than the above point, the evaporator of the
present embodiment is the same as the evaporator of FIG. 16 and
provides the same effects and the same advantages as those of the
evaporator of FIG. 16.
[0155] The refrigerant flow pattern in the evaporator of the
present embodiment is constructed from three downstream side flow
passage rows and three upstream side flow passage rows. The three
downstream side flow passage rows include one downstream side flow
passage row 21a (the refrigerant upflow portion), one downstream
side flow passage row 21b (the refrigerant downflow portion) and
one furthermost downstream side flow passage row 210 (the
refrigerant upflow portion). The three upstream side flow passage
rows include one furthermost upstream side flow passage row 220
(the refrigerant upflow portion), one upstream side flow S passage
row 22b (the refrigerant downflow portion) and one upstream side
flow passage row 22a (the refrigerant upflow portion).
[0156] Therefore, the number of the refrigerant flow paths in the
core 100 is five in the present embodiment. Furthermore, the
refrigerant flow pattern in the evaporator is expressed by the
number of path(s) in the downstream side flow passage rows 21, the
number of path(s) in the upstream side flow passage row 22 and the
number of path(s) of the full-path portion 200 (the portion where
the branched flow of the refrigerant from the downstream side to
the upstream side flows upwardly). These numbers are written one
after another according to the flow order of the refrigerant in the
evaporator and are thereby expressed as a 2-1-2 refrigerant flow
pattern in this instance.
[0157] Next, the flow of the refrigerant in the evaporator will be
sequentially described. The refrigerant from the external
constituent component of the refrigeration cycle is supplied into
the downstream side lower tank 41, which is the space on the left
lateral side of the separator 41a (the side of the separator 41a,
which is opposite from the X-direction) through the lower flow
inlet 51. Then, the refrigerant flows upwardly through the
downstream side flow passage row 21a (the first path). Next, the
flow direction of this refrigerant is reversed in the interior of
the downstream side upper tank 31, which is the space on the left
lateral side of the separator 31a (the side of the separator 31a,
which is opposite from the X-direction), and thereafter the
refrigerant flows downwardly through the downstream side flow
passage row 21b (the second path). Thereafter, this refrigerant is
supplied into the interior of the furthermost downstream side lower
tank 411.
[0158] A portion of the refrigerant in the downstream side lower
tank 411 is branched and flows toward the upstream side of the air
flow (the side opposite from the Z-direction) through the
communication holes 400 in the second communication passage 43.
Then, this refrigerant is supplied into the upstream side lower
tank 421. Then, this refrigerant flows upwardly through the
upstream side flow passage row 220 (the third path, the full-path
portion 200) and is supplied into the upstream side upper tank
321.
[0159] In contrast, the remaining refrigerant in the downstream
side lower tank 411, which is other than the branched portion of
the refrigerant, flows upwardly through the furthermost downstream
side flow passage row 210 (the third path, the full-path portion
200) and then flows from the interior of the downstream side upper
tank 311 toward the upstream side of the air flow into the upstream
side upper tank 321 through the communication holes 300 in the
first communication passage 33. Then, this refrigerant is merged
with the above branched portion of the refrigerant, which is
supplied through the furthermost upstream side flow passage row 220
after flowing upwardly therethrough. That is, the refrigerant in
the furthermost downstream side flow passage row 210 and the
refrigerant in the furthermost upstream side flow passage row 220
flow upwardly parallel to one another.
[0160] The flow direction of the merged refrigerant, which is
merged in the interior of the upstream side upper tank 321, is
reversed, and this refrigerant flows downwardly through the
upstream side flow passage row 22b (the fourth path). Then, the
flow direction of this refrigerant is reversed once again in the
upstream side lower tank 42, and thereby the refrigerant flows
upwardly through the upstream side flow passage row 22a (the fifth
path). Thereafter, this refrigerant flows to the outside of the
core from the upstream side upper tank 32 through the flow outlet
52.
Eleventh Embodiment
[0161] An eleventh embodiment of the present invention is a
modification (a case where the refrigerant flow pattern is 3-1-1
pattern) of the evaporator of the tenth embodiment and will be
described with reference to FIG. 18. FIG. 18 is a schematic diagram
showing the structure of the evaporator and the refrigerant flow
therethrough in the case where the refrigerant flow pattern is
3-1-1 according to the present embodiment.
[0162] In the evaporator of the present embodiment, the number of
the refrigerant flow paths is five, which is the same as that of
the evaporator of FIG. 17. However, the evaporator of the present
embodiment is different from the evaporator of FIG. 17 with respect
to the refrigerant flow pattern (3-1-1 pattern in the present
embodiment) and the flow direction of the refrigerant in the
furthermost portion (the refrigerant downflow portion in this
embodiment) of the core 105. Other than the above points, the
evaporator of the present embodiment is the same as the evaporator
of FIG. 17 and provides the same effects and the same advantages as
those of the evaporator of FIG. 17.
[0163] The refrigerant flow pattern in the evaporator of the
present embodiment is constructed from four downstream side flow
passage rows and two upstream side flow passage rows. The four
downstream side flow passage rows include two downstream side flow
passage rows 21a (the refrigerant upflow portions), one downstream
side flow passage row 21b (the refrigerant downflow portion) and
one furthermost downstream side flow passage row 211 (the
refrigerant downflow portion). The two upstream side flow passage
rows include one furthermost upstream side flow passage row 221
(the refrigerant downflow portion) and one upstream side flow
passage row 22a (the refrigerant upflow portion).
[0164] Therefore, the number of the refrigerant flow paths in the
core 105 is five in the present embodiment. Furthermore, the
refrigerant flow pattern in the evaporator is expressed by the
number of path(s) in the downstream side flow passage rows 21, the
number of path(s) in the upstream side flow passage row 22 and the
number of path(s) of the full-path portion 200 (the portion where
the branched flow of the refrigerant from the downstream side to
the upstream side flows upwardly). These numbers are written one
after another according to the flow order of the refrigerant in the
evaporator and are thereby expressed as a 3-1-1 refrigerant flow
pattern in this instance.
[0165] Next, the flow of the refrigerant in the evaporator will be
sequentially described. The refrigerant from the external
constituent component of the refrigeration cycle is supplied into
the downstream side lower tank 41, which is the space on the left
lateral side of the separator 41a (the side of the separator 41a,
which is opposite from the X-direction) through the lower flow
inlet 51. Then, the refrigerant flows upwardly through the
downstream side flow passage row 21a (the first path). Next, the
flow direction of this refrigerant is reversed in the interior of
the downstream side upper tank 31, which is the space on the left
lateral side of the separator 31a (the side of the separator 31a,
which is opposite from the X-direction), and thereafter the
refrigerant flows downwardly through the downstream side flow
passage row 21b (the second path). Thereafter, the flow direction
of this refrigerant is reversed in the interior of the downstream
side lower tank 41, which is the space defined between the
separator 41a and the separator 41b. Then, this refrigerant flows
upwardly through the downstream side flow passage row 21a (the
third path) and is supplied into the interior of the furthermost
downstream side upper tank 311.
[0166] A portion of the refrigerant in the downstream side upper
tank 311 is branched and flows toward the upstream side of the air
flow (the side opposite from the Z-direction) through the
communication holes 300 in the first communication passage 33.
Then, this refrigerant is supplied into the upstream side upper
tank 321. Then, this refrigerant flows downwardly through the
upstream side flow passage row 221 (the fourth path, the full-path
portion 201) and is supplied into the upstream side lower tank
421.
[0167] In contrast, the remaining refrigerant in the downstream
side upper tank 311, which is other than the branched portion of
the refrigerant, flows downwardly through the furthermost
downstream side flow passage row 211 (the fourth path, the
full-path portion 201) and then flows from the interior of the
downstream side lower tank 411 toward the upstream side of the air
flow into the upstream side lower tank 421 through the
communication holes 400 in the second communication passage 43.
Then, this refrigerant is merged with the above branched portion of
the refrigerant, which is supplied through the furthermost upstream
side flow passage row 221 after flowing downwardly therethrough, in
the upstream side lower tank 421. That is, the refrigerant in the
furthermost downstream side flow passage row 211 and the
refrigerant in the furthermost upstream side flow passage row 221
flow downwardly parallel to one another.
[0168] Next, the flow direction of the merged refrigerant, which is
merged in the upstream side lower tank 421, is reversed, and this
refrigerant flows upwardly through the upstream side flow passage
row 22a (the fifth path) and is supplied into the upstream side
upper tank 32, which is the space on the left lateral side of the
separator 32a (the side of the separator 32a, which is opposite
from the X-direction). Thereafter, this refrigerant flows to the
outside of the core from the upstream side upper tank 32 through
the flow outlet 52.
[0169] Furthermore, in the evaporator of the present embodiment,
the number of the downstream side flow passage rows 21 and the
number of the upstream side flow passage rows 22 are set as
follows. That is, the number of the other downstream side flow
passage rows 21a, 21b other than the furthermost downstream side
flow passage row 211 is three, and the number of the other upstream
side flow passage row 22a, 22b other than the furthermost upstream
side flow passage row 221 is one. Therefore, the number of the
other downstream side flow passage rows 21a, 21b other than the
furthermost downstream side flow passage row 211 is greater than
the number of the other upstream side flow passage row 22a, 22b
other than the furthermost upstream side flow passage row 221. With
the above structure, in the case of the heat exchanger, in which
the dryness of the refrigerant is larger on the downstream side in
comparison to the upstream side, it is possible to reduce the
pressure loss.
Twelfth Embodiment
[0170] In a twelfth embodiment of the present invention, a
modification (a case of four paths of refrigerant flow) of the
evaporator of the eleventh embodiment will be described with
reference to FIG. 19. FIG. 19 is a schematic diagram showing the
structure of the evaporator and the refrigerant flow therethrough
in the case where the refrigerant flow pattern is 2-1-1 according
to the present embodiment.
[0171] The evaporator of the present embodiment is different from
the evaporator of FIG. 18 with respect to the number of the paths
(four paths in this embodiment) and the refrigerant flow patter
(2-1-1 pattern in this embodiment). Other than the above point, the
evaporator of the present embodiment is the same as the evaporator
of FIG. 18 and provides the same effects and the same advantages as
those of the evaporator of FIG. 18.
[0172] The refrigerant flow pattern in the evaporator of the
present embodiment is constructed from three downstream side flow
passage rows and two upstream side flow passage rows. The three
downstream side flow passage rows include one downstream side flow
passage row 21b (the refrigerant downflow portion), one downstream
side flow passage row 21a (the refrigerant upflow portion) and one
furthermost downstream side flow passage row 211 (the refrigerant
downflow portion). The two upstream side flow passage rows include
one furthermost upstream side flow passage row 221 (the refrigerant
downflow portion) and one upstream side flow passage row 22a (the
refrigerant upflow portion).
[0173] Therefore, the number of the refrigerant flow paths in the
core 102 is four in the present embodiment. Furthermore, the
refrigerant flow pattern in the evaporator is expressed by the
number of path(s) in the downstream side flow passage rows 21, the
number of path(s) in the upstream side flow passage row 22 and the
number of path(s) of the full-path portion 201 (the portion where
the branched flow of the refrigerant from the downstream side to
the upstream side flows downwardly). These numbers are written one
after another according to the flow order of the refrigerant in the
evaporator and are thereby expressed as a 2-1-1 refrigerant flow
pattern in this instance.
[0174] Next, the flow of the refrigerant in the evaporator will be
sequentially described. The refrigerant from the external
constituent component of the refrigeration cycle is supplied into
the downstream side upper tank 31, which is the space on the left
lateral side of the separator 31a (the side of the separator 31a,
which is opposite from the X-direction) through the upper flow
inlet 51. Then, the refrigerant flows downwardly through the
downstream side flow passage row 21b (the first path). Next, the
flow direction of this refrigerant is reversed in the interior of
the downstream side lower tank 41, which is the space on the left
lateral side of the separator 41a (the side of the separator 41a,
which is opposite from the X-direction), and thereafter the
refrigerant flows upwardly through the downstream side flow passage
row 21a (the second path) and is supplied into the interior of the
furthermost downstream side upper tank 311.
[0175] A portion of the refrigerant in the downstream side upper
tank 311 is branched and flows toward the upstream side of the air
flow (the side opposite from the Z-direction) through the
communication holes 300 in the first communication passage 33.
Then, this refrigerant is supplied into the upstream side upper
tank 321. Then, this refrigerant flows downwardly through the
furthermost upstream side flow passage row 221 (the third path, the
full-path portion 201) and is supplied into the upstream side lower
tank 421.
[0176] In contrast, the remaining refrigerant in the downstream
side upper tank 311, which is other than the branched portion of
the refrigerant, flows downward through the furthermost downstream
side flow passage row 211 (the third path, the full-path portion
201) and then flows from the interior of the downstream side lower
tank 411 toward the upstream side of the air flow into the upstream
side lower tank 421 through the communication holes 400 in the
second communication passage 43. Then, this refrigerant is merged
with the above branched portion of the refrigerant, which is
supplied through the furthermost upstream side flow passage row 221
after flowing downwardly therethrough, in the upstream side lower
tank 421. That is, the refrigerant in the furthermost downstream
side flow passage row 211 and the refrigerant in the furthermost
upstream side flow passage row 221 flow downwardly parallel to one
another.
[0177] Next, the flow direction of the merged refrigerant, which is
merged in the upstream side lower tank 421, is reversed, and this
refrigerant flows upwardly through the upstream side flow passage
row 22a (the fourth path) and is supplied into the upstream side
upper tank 32, which is the space on the left lateral side (the
side of the separator 32a, which is opposite from the X-direction).
Thereafter, this refrigerant flows to the outside of the core from
the upstream side upper tank 32 through the flow outlet 52.
Thirteenth Embodiment
[0178] In a thirteenth embodiment of the present invention, a
modification (a case of three paths of refrigerant flow) of the
evaporator of the twelfth embodiment will be described with
reference to FIG. 20. FIG. 20 is a schematic diagram showing the
structure of the evaporator and the refrigerant flow therethrough
in the case where the refrigerant flow pattern is 1-1-1 according
to the present embodiment.
[0179] The evaporator of the present embodiment is different from
the evaporator of FIG. 19 with respect to the structure of the core
106, the number of refrigerant flow paths (three in this
embodiment), the refrigerant flow pattern (1-1-1 pattern in this
embodiment) and the location of the flow inlet 51 (lower side in
this embodiment). Other than the above points, the evaporator of
the present embodiment is the same as the evaporator of FIG. 19 and
provides the same effects and the same advantages as those of the
evaporator of FIG. 19.
[0180] The refrigerant flow pattern in the evaporator 1 of the
present embodiment is constructed from two downstream side flow
passage rows and two upstream side flow passage rows. The two
downstream side flow passage rows include one downstream side flow
passage row 21a (the refrigerant upflow portion) and one
furthermost downstream side flow passage row 211 (the refrigerant
downflow portion). The two upstream side flow passage rows include
one furthermost upstream side flow passage row 221 (the refrigerant
downflow portion) and one upstream side flow passage row 22a (the
refrigerant upflow portion).
[0181] Therefore, the number of the refrigerant flow paths in the
core 106 is three in the present embodiment. Furthermore, the
refrigerant flow pattern in the evaporator is expressed by the
number of path(s) in the downstream side flow passage rows 21, the
number of path(s) in the upstream side flow passage row 22 and the
number of path(s) of the full-path portion 201 (the portion where
the branched flow of the refrigerant from the downstream side to
the upstream side flows downwardly). These numbers are written one
after another according to the flow order of the refrigerant in the
evaporator and are thereby expressed as a 1-1-1 refrigerant flow
pattern in this instance.
[0182] Next, the flow of the refrigerant in the evaporator will be
sequentially described. The refrigerant from the external
constituent component of the refrigeration cycle is supplied into
the interior of the downstream side lower tank 41, which is the
space on the left lateral side of the separator 41a (the side of
the separator 41a, which is opposite from the X-direction) through
the lower flow inlet 51. Then, the refrigerant flows upwardly
through the downstream side flow passage row 21a (the first path)
and is supplied into the downstream side upper tank 311.
[0183] A portion of the refrigerant in the downstream side upper
tank 311 is branched and flows toward the upstream side of the air
flow (the side opposite from the Z-direction) through the
communication holes 300 in the first communication passage 33.
Then, this refrigerant is supplied into the upstream side upper
tank 321. Then, this refrigerant flows downwardly through the
upstream side flow passage row 221 (the second path, the full-path
portion 201) and is supplied into the upstream side lower tank
421.
[0184] In contrast, the remaining refrigerant in the downstream
side upper tank 311, which is other than the branched portion of
the refrigerant, flows downwardly through the furthermost
downstream side flow passage row 211 (the second path, the
full-path portion 201) and then flows from the interior of the
downstream side lower tank 411 toward the upstream side of the air
flow into the upstream side lower tank 421 through the
communication holes 400 in the second communication passage 43.
Then, this refrigerant is merged with the above branched portion of
the refrigerant, which is supplied through the furthermost upstream
side flow passage row 221 after flowing downwardly therethrough, in
the upstream side lower tank 421. That is, the refrigerant in the
furthermost downstream side flow passage row 211 and the
refrigerant in the furthermost upstream side flow passage row 221
flow downwardly parallel to one another.
[0185] Next, the flow direction of the merged refrigerant, which is
merged in the upstream side lower tank 421, is reversed, and this
refrigerant flows upwardly through the upstream side flow passage
row 22a (the third path) and is supplied into the upstream side
upper tank 32, which is the space on the left lateral side of the
separator 32a (the side of the separator 32a, which is opposite
from the X-direction). Thereafter, this refrigerant flows to the
outside of the core from the upstream side upper tank 32 through
the flow outlet 52.
Fourteenth Embodiment
[0186] In a fourteenth embodiment of the present invention, the
positioning state of the evaporator (the state where the core is
tilted relative to the horizontal direction), which is applicable
to all of the embodiments of the present invention, will be
described with reference to FIG. 21. FIG. 21 is a schematic side
view of the positioning state of the evaporator according to the
present embodiment. FIG. 22 is an enlarged partial cross sectional
side view showing the relationship between the interior of the
upper header tank 3 and the refrigerant quantities (the refrigerant
quantity in the upstream side and the refrigerant quantity in the
downstream side) in the core 100 at the furthermost portion
thereof. FIG. 23 is an enlarged partial cross sectional side view
showing the relationship between the interior of the lower header
tank 4 and the refrigerant quantities (the refrigerant quantity in
the upstream side and the refrigerant quantity in the downstream
side) in the core 100 at the furthermost portion thereof.
[0187] With reference to FIG. 21, the core 100 has an upstream side
lateral core surface (upstream side lateral plane) 100b and a
downstream side lateral core surface (downstream side lateral
plane) 100a, which are generally parallel to each other and are
located on the upstream side and the downstream side, respectively,
in the air flow direction. The evaporator of the present embodiment
is tilted such that the upstream side lateral core surface 100b of
the core 100 is closer to an imaginary horizontal plane L indicated
by a dot-dash line in FIG. 21 (a plane that is placed vertically
below the upstream side lower tank 42 and is parallel to the
Z-direction) in comparison to the downstream side lateral core
surface 100a of the core 100. The core 100 is placed and is held at
a tilt angle (specifically, a tilt angle of the upstream side
lateral core surface 100b) .theta. relative to the imaginary
horizontal plane (the imaginary horizontal line) L. Other than this
point, the evaporator of the present embodiment is the same as the
evaporator 1 of the first embodiment and provides the same effects
and the same advantages as those of the evaporator 1 of the first
embodiment.
[0188] With this structure, due to the aid of the gravity, a
portion of the refrigerant in the furthermost downstream side
header tank 11 (e.g., the furthermost downstream side upper tank
311 in the case of FIG. 22 and the furthermost downstream side
lower tank 411 in the case of FIG. 23) flows in the greater amount
in comparison to the first embodiment through the communicating
means (the first communication passage 33 or 33A in the case of
FIG. 22 and the second communication passage 43 or 43A in the case
of FIG. 23) toward the upstream side of the air flow and is
supplied into the furthermost upstream side header tank 12 (e.g.,
the furthermost upstream side upper tank 321 in the case of FIG. 22
and the furthermost upstream side lower tank 421 in the case of
FIG. 23). At this time, the refrigerant is under the influence of
the gravity, so that the refrigerant tends to flow through the
communicating means toward the upstream side flow passage row 220,
221 rather than the furthermost downstream side flow passage row
210, 211 due to the fact that the upstream side flow passage row
220, 221 is placed at the lower side of the furthermost downstream
side flow passage row 210, 211 in the vertical direction.
Furthermore, the portion of the refrigerant, which is supplied into
the upstream side header tank 12 (e.g., the furthermost upstream
side upper tank 321 in the case of FIG. 22 and the upstream side
lower tank 421 in the case of FIG. 23) flows through the
furthermost upstream side flow passage row 220, 221 toward the
opposite upstream side header tank 12 (e.g., the furthermost
upstream side lower tank 421 in the case of FIG. 22 and the
furthermost upstream side upper tank 321 in the case of FIG. 23),
which is opposite from the above upstream side header tank 12
(e.g., the furthermost upstream side upper tank 321 in the case of
FIG. 22 and the upstream side lower tank 421 in the case of FIG.
23) in the top-to-bottom direction of the core 100.
[0189] In contrast, the rest of the refrigerant, which remains in
the furthermost downstream side header tank 11 (e.g., the
furthermost downstream side upper tank 311 in the case of FIG. 22
and the furthermost downstream side lower tank 411 in the case of
FIG. 23) flows through the furthermost downstream side flow passage
row 210, 211 toward the opposite furthermost downstream side header
tank 11 (e.g., the furthermost downstream side lower tank 411 in
the case of FIG. 22 and the furthermost downstream side upper tank
311 in the case of FIG. 23), which is opposite from the above
downstream side header tank 11 (e.g., the furthermost downstream
side upper tank 311 in the case of FIG. 22 and the furthermost
downstream side lower tank 411 in the case of FIG. 23) in the
top-to-bottom direction of the core 100. Then, this refrigerant
flows toward the upstream side of the air flow into the upstream
side header tank 12 (e.g., the furthermost upstream side lower tank
421 in the case of FIG. 22 and the upstream side upper tank 321 in
the case of FIG. 23) where this refrigerant is merged with the
branched portion of the refrigerant, which has passed through the
communicating means.
[0190] At the evaporator of the present embodiment, in the case
where the furthermost flow passage rows (the furthermost upstream
side and downstream side flow passage rows) form the refrigerant
downflow portions (the full-path portion 201), the quantity of the
refrigerant, which flows through the furthermost upstream side flow
passage row 221, becomes greater than the quantity of the
refrigerant, which flows through the furthermost downstream side
flow passage row 211 (see FIG. 22). Furthermore, in the case where
the furthermost flow passage rows form the refrigerant upflow
portions (the full-path portion 200), the quantity of the
refrigerant, which flows through the furthermost upstream side flow
passage row 220, becomes larger than the quantity of the
refrigerant, which flows through the furthermost downstream side
flow passage row 210 (see FIG. 23).
[0191] In the evaporator of the present embodiment, the furthermost
upstream side flow passage row 220, 221 is placed on the lower side
of the furthermost downstream side flow passage row 210, 211, so
that the refrigerant in the downstream side header tank 11 tends to
flow toward the furthermost upstream side flow passage row 220, 221
due to the gravity. Therefore, it is possible to alleviate the
biased flow of the refrigerant, which tends to flow toward the
downstream side flow passage row at the furthermost portion of the
core that is furthermost from the flow inlet 51 and the flow outlet
52.
[0192] Also, in the evaporator, the refrigerant of the gas phase
and liquid phase mixture is supplied into the downstream side
header tank 11. The liquid phase refrigerant is heavier than the
gas phase refrigerant. Thus, in addition to the inertial force, the
gravity has the significant influence on the liquid phase
refrigerant. Therefore, the liquid phase refrigerant is expected to
flow toward the upstream side flow passage row 220, 221, which is
placed on the lower side of the downstream side flow passage row
210, 211. Thereby, the refrigerant can be more actively supplied to
the upstream side where the temperature of the blown air is
relatively high, so that the heat exchange performance can be
further improved.
Fifteenth Embodiment
[0193] In a fifteenth embodiment of the present invention, the
structure of the header tank, which is applicable to the evaporator
of all of the embodiments of the present invention, will be
described with reference to FIGS. 24 to 26. FIG. 24 is a partial
side view showing the upper header tank 3 of the evaporator of the
present embodiment. FIG. 25 is a partial cross sectional front view
showing the flow inlet 51 of the upper header tank 3 of FIG. 24
seen from the X-direction in FIG. 24. FIG. 26 is a diagram (graph)
showing a computed result of a relationship between a tank outer
diameter (a total tank outer diameter of the upstream side and
downstream side header tanks or a total thickness of the upstream
side and downstream side header tanks in the air flow direction) D
and a pressure loss in the tank obtained under a predetermined
condition.
[0194] As shown in FIGS. 24 and 25, the upper header tank 3 and the
tubes 20 are formed from a plurality of plate members (constituent
members) 50, which are integrally stacked and joined one after
another in the lateral direction. The plate member 50 has a through
hole and an extending portion. The extending portion of the plate
member 50 extends from the through hole of the plate member 50 in
the direction opposite from the Y-direction. One side of the
through hole of the plate member 50 is configured into a plate
form, and the other side of the through hole of the plate member 50
is configured into a tubular form. The upper header tank 3 is
formed by alternately directing and stacking the plate members 50
of the above configuration, so that the tubular portion, which
extends in the X-direction, and the flow passages, which conduct
the refrigerant, are created. Furthermore, it should be noted that
although not show in the drawing, the lower header tank 4 is also
formed at the undepicted lower ends of the tubes 20 in FIG. 24 in a
manner similar to that of the upper header tank 3.
[0195] The above tubular portion, which extends in the X-direction,
constitutes the tank, and the lateral side end opening of the
tubular portion can be used as the flow inlet 51 or the flow outlet
52. When the lateral side end opening of the tubular portion is not
used as the flow inlet 51 or the flow outlet 52, the cap is fitted
into the lateral side end opening to close the same. The tank
interior (the tube interior) is communicated with the flow passages
(the interiors of the tubes), which extend in the direction
opposite from the Y-direction.
[0196] FIG. 26 shows the relationship between the tank outer
diameter or the thickness D (mm) and the pressure loss (kPa) in the
case of the separate type tank (indicated by a solid line) where
separate tubes are joined to the tank. FIG. 26 also shows the
relationship between the tank outer diameter D (mm) and the
pressure loss (kPa) in the case of the laminate type tank
(indicated by a dotted line) where the plate members 50 are
stacked. The tank outer diameter D is defined by the following
equation 1.
D=2(d+2t) Equation 1
[0197] Here, "t" denotes a wall thickness of the tank. Furthermore,
"d" denotes an equivalent inner diameter of the interior of the
tank, which is obtained as follows. That is, first, an effective
cross sectional area of the interior of the tank is multiplied by
4, and then the thus obtained value (i.e., the product of the
effective cross sectional area multiplied by 4) is divided by a
circumferential length of the interior of the tank to obtain the
equivalent inner diameter of the interior of the tank.
[0198] Furthermore, in the case of the separate type tank, the data
of FIG. 26 is computed for the corresponding predetermined
condition where the wall thickness t of the tank is 1.0 mm (i.e.,
t=1.0 mm), and a protrusion of the tube into the interior of the
tank is minimum of 4 mm. In the case of the laminate type tank, the
data of FIG. 26 is computed for the corresponding predetermined
condition where the wall thickness t of the tank is 1.0 mm (i.e.,
t=1.0 mm), and the tank brazing area is 1.5 to 3.0 mm.
[0199] In the result of the computation of the above separate type
tank and of the laminate type tank, the pressure loss factors are
compared by using a square of an inverse (a flow velocity factor)
of the effective cross sectional area of the interior of the tank.
Furthermore, the comparison is made by using the pressure loss
factor in the case of the tank outer diameter D=70 mm as a
reference.
[0200] As shown in FIG. 26, according to the result of the
computation, it is desirable that the thickness D of the both
header tanks (the upstream side and downstream side header tanks),
which is measured in the air flow direction, is 48 mm or less. In
this case, the tank interior space is not large, and thereby the
pressure loss in the tank tends to become large. Here, when the
present invention is applied to the evaporator, which satisfies the
above condition, the more prominent effect for reducing the
pressure loss can be expected.
Sixteenth Embodiment
[0201] In a sixteenth embodiment of the present invention, an
appropriate relationship between a total passage cross sectional
area S1 of the branching passage and a total passage cross
sectional area S2 of the merging passage, which is applicable to
all of the embodiments of the present invention, will be described
with reference to FIGS. 27 and 28. FIG. 27 is a schematic diagram
for designing the appropriate condition of the flow quantity
(hereinafter, also referred to as the upstream side refrigerant
flow quantity) GR2 of the refrigerant, which flows in the upstream
side flow passage row, and the flow quantity (hereinafter, also
referred to as the downstream side refrigerant flow quantity) GR1
of the refrigerant, which flows in the downstream side flow passage
row. FIG. 28 is a diagram showing the result of the computation of
an appropriate ratio (S1/S2) between the total passage cross
sectional area S1 of the branching passage and the total passage
cross sectional area S2 of the merging passage computed for each
corresponding one of the refrigerant flow paths (3 paths to 6
paths).
[0202] As shown in FIG. 27, in the case where the furthermost
downstream side flow passage row and the furthermost upstream side
flow passage row are refrigerant upflow portions, respectively, the
flow quantity of the refrigerant flowing through the furthermost
downstream side flow passage row is indicated by "GR1", and the
flow quantity of the refrigerant flowing through the furthermost
upstream side flow passage row is indicated by "GR2". Furthermore,
the flow quantity of the refrigerant flowing from the furthermost
downstream side upper tank 311 to the furthermost upstream side
upper tank 321 is indicated by "GRU", and the flow quantity of the
refrigerant flowing from the furthermost downstream side lower tank
411 to the furthermost upstream side lower tank 421 is indicated by
"GRL".
[0203] Furthermore, the number of the refrigerant flow paths in the
core is indicated by "N". At the second communication passage 43 or
43A (the branching passage), which conducts the portion of the
refrigerant from the furthermost downstream side lower tank 411 to
the furthermost upstream side lower tank 421, the pressure loss is
indicated by ".DELTA.Pt1", and the dryness is indicated by "X1".
Also, the specific volume at the second communication passage 43 is
indicated by "V1". In addition, at the first communication passage
33 or 33A (the merging passage), which conducts the remaining
refrigerant from the downstream side upper tank 311 to the upstream
side upper tank 321 after the remaining refrigerant being supplied
from the furthermost downstream side lower tank 411 to the
furthermost downstream side upper tank 311 through the furthermost
downstream side flow passage row 210, the pressure loss is
indicated by ".DELTA.Pt2", and the dryness is indicated by "X2".
Also, the specific volume at the first communication passage 33 is
indicated by "V2".
[0204] In comparison between the upstream side portion (the
upstream side flow passage row) of the core and the downstream side
portion (the downstream side flow passage row) of the core, which
are placed one after another in the flow direction of the air, the
air around the upstream side portion of the core is warmer.
Therefore, the upstream side portion of the core should have the
higher performance. In a typical condition (an ideal condition),
the good balance of the performance is achieved with the following
state. That is, the air to be supplied to the core has the
temperature of 27.degree. C. and the relative humidity of 50% RH.
Furthermore, the air right after passing through the upstream side
portion (the upstream side flow passage row) of the core has the
temperature of 14.degree. C. and the relative humidity of 85% RH,
and the air right after passing through the downstream side portion
(the downstream side flow passage row) of the core has the
temperature of 7.degree. C. and the relative humidity of 90%
RH.
[0205] When the amount of energy is computed for the above state,
the ratio between the downstream side refrigerant flow quantity GR1
and the upstream side refrigerant flow quantity GR2 is 4:6. The
above balance may vary about .+-.10% due to the variation in the
distribution of the refrigerant in the lateral direction (the width
direction) of the core. In view of the above fact, it is desirable
to set the ratio of GR1/GR2 to be equal to or greater than 0.55
(=3.6/6.6) but is equal to or less than 0.81 (=4.4/5.4), i.e.,
0.55.ltoreq.GR1/GR2.ltoreq.0.81.
[0206] Next, the result (see FIG. 28) of the computation of the
appropriate ratio (S1/S2) between the total passage cross sectional
area S1 of the branching passage and the total passage cross
sectional area S2 of the merging passage will be described in view
of the number of the refrigerant flow paths of the evaporator.
[0207] The logic of the computation will now be described. First,
it should be understood that the dryness of the refrigerant before
entering the core differs from the dryness of the refrigerant after
exiting the core. In view of this fact, when the pressure loss
.DELTA.Pt1 of the branching passage is set to be smaller than the
pressure loss .DELTA.Pt2 of the merging passage (i.e.,
.DELTA.Pt1<.DELTA.Pt2), the refrigerant flow quantity of the
downstream side and the refrigerant flow quantity of the upstream
side can be balanced.
[0208] The refrigerant flow quantity balance and the pressure loss
depend on the square of the flow velocity of the refrigerant, so
that it is desirable to satisfy the following equation 2.
S1/S2=(V1/V2).sup.2 Equation 2
[0209] Furthermore, it is desirable that the refrigerant flow
quantity in the upstream side portion of the core is larger than
the refrigerant flow quantity in the downstream side portion of the
core. Thus, it is desirable to have the value of S1/S2, which is
equal to or larger than the corresponding value shown in the column
of "ANSWER" in FIG. 28.
[0210] As indicated in FIG. 28, it is desirable that the heat
exchanger is constructed to satisfy a condition of
0.41.ltoreq.S1/S2. Furthermore, as discussed above, in the case
where the furthermost downstream side flow passage row and the
furthermost upstream side flow passage row are refrigerant upflow
portions, respectively, the total passage cross sectional area S1
of the branching passage is the total passage cross sectional area
S1 of the second communication passage 43, and the total passage
cross sectional area S2 of the merging passage is the total passage
cross sectional area S2 of the first communication passage 33.
Furthermore, in a case where the second communication passage 43
includes a plurality of sub-passages, the total passage cross
sectional area S1 is a sum of all of cross sectional areas of the
sub-passages of the second communication passage 43. Similarly, in
a case where the first communication passage 33 includes a
plurality of sub-passages, the total passage cross sectional area
S2 is a sum of all of cross sectional areas of the sub-passages of
the first communication passage 33. Also, in a case where the
second communication passage 43 is made of a single passage, the
total passage cross sectional area S1 is the cross sectional area
of this single passage. Similarly, in a case where first
communication passage 33 is made of a single passage, the total
passage cross sectional area S2 is the cross sectional area of this
single passage.
[0211] In contrast, in the case where the furthermost downstream
side flow passage row and the furthermost upstream side flow
passage row are refrigerant downflow portions, respectively, the
total passage cross sectional area S1 of the branching passage is
the total passage cross sectional area S1 of the first
communication passage 33, and the total passage cross sectional
area S2 of the merging passage is the total passage cross sectional
area S2 of the second communication passage 43. Furthermore, in a
case where the first communication passage 33 includes a plurality
of sub-passages, the total passage cross sectional area Si is a sum
of all of cross sectional areas of the sub-passages of the first
communication passage 33. Similarly, in a case where the second
communication passage 43 includes a plurality of sub-passages, the
total passage cross sectional area S2 is a sum of all of cross
sectional areas of the sub-passages of the second communication
passage 43. Also, in a case where the first communication passage
33 is made of a single passage, the total passage cross sectional
area S1 is the cross sectional area of this single passage.
Similarly, in a case where second communication passage 43 is made
of a single passage, the total passage cross sectional area S2 is
the cross sectional area of this single passage.
[0212] In addition, as shown in FIG. 28, in the case where the
number of the refrigerant flow paths in the core is six, it is
desirable to satisfy the condition of 0.71.ltoreq.S1/S2.
Furthermore, in the case where the number of the refrigerant flow
paths in the core is five, it is desirable to satisfy the
relationship of 0.47.ltoreq.S1/S2. Furthermore, in the case where
the number of the refrigerant flow paths in the core is four, it is
desirable to satisfy the relationship of 0.66.ltoreq.S1/S2. In
addition, in the case where the number of the refrigerant flow
paths in the core is three, it is desirable to satisfy the
relationship of 0.41.ltoreq.S1/S2.
Seventeenth Embodiment
[0213] In a seventeenth embodiment of the present invention, cores,
in which the lateral size (lateral extension) of the furthermost
upstream side flow passage row 220, 221 and the lateral size
(lateral extension) of the furthermost downstream side flow passage
row 210, 211 measured in the X-direction (lateral direction of the
core) are not identical, will be described with reference to FIGS.
29 and 30. FIG. 30 is a schematic diagram showing a variation of
the evaporator of FIG. 29 along with the structure and the
refrigerant flow thereof. Here, it should be noted that although
FIGS. 29 and 30 do not show the communication passage forming
member(s) 34, 44 of the first to sixth embodiments, the present
embodiment is equally applicable to the evaporator of any one of
the first to sixth embodiments with the communication passage
forming member(s) 34, 44. In other words, FIGS. 29 and 30 are only
for the purpose of showing the difference between the lateral size
(lateral extension) of the furthermost upstream side flow passage
row 220, 221 and the lateral size (lateral extension) of the
furthermost downstream side flow passage row 210, 211.
[0214] FIG. 29 is a schematic diagram showing the structure and the
refrigerant flow in the case of the evaporator, in which the
lateral size of the furthermost upstream side flow passage row 221
is larger than the lateral size of the furthermost downstream side
flow passage row 211. Furthermore, in this evaporator, the
furthermost downstream side flow passage row and the furthermost
upstream side flow passage row are the refrigerant downflow
portions, respectively, and the refrigerant flow pattern is a 1-1-1
refrigerant flow pattern. In addition, the number of the
refrigerant flow paths is three.
[0215] Next, FIG. 30 is the schematic diagram showing the structure
and the refrigerant flow in the case of the evaporator, in which
the lateral size of the furthermost downstream side flow passage
row 211 is larger than the lateral size of the furthermost upstream
side flow passage row 221. Furthermore, in this evaporator, the
furthermost downstream side flow passage row and the furthermost
upstream side flow passage row are the refrigerant downflow
portions, respectively, and the refrigerant flow pattern is a 1-1-1
refrigerant flow pattern. In addition, the number of the
refrigerant flow paths is three.
Eighteenth Embodiment
[0216] In an eighteenth embodiment of the present invention, a
positional relationship between the communication passage forming
member and the core, which is applicable to all of the embodiments
of the present invention, will be described with reference to FIGS.
31 to 33. FIG. 31 is a partial schematic front view showing the
relationship between the communication passage forming member 44
and the core. FIG. 32 is a partial schematic front view showing the
relationship between the communication passage forming member 44
and the core in a modification of FIG. 31. FIG. 33 is a partial
schematic front view showing the relationship between the
communication passage forming member 44 and the core in a further
modification of the FIG. 31.
[0217] As shown in FIGS. 31 to 33, the communication passage
forming member 44 is provided such that at least a portion of the
communication passage forming member 44 is placed laterally inward
(on the left side in FIGS. 31-33) of the lateral end of the core
100. With this construction, a dead space can be reduced to reduce
the lateral size of the core.
[0218] In FIG. 31, a longitudinal end portion of the side plate
500, which supports the core, is inserted into the interior of the
communication passage forming member 44. Alternatively, a
longitudinal end portion of the lateral end tube 20a, which is
located at the lateral ends of the core, may be inserted into the
interior of the communication passage forming member 44. With this
construction, even in the case where the portion of the
communication passage forming member 44 is placed laterally inward
of the lateral end of the core, it is not required to make any
particular adjustment of the longitudinal end portion of the tube
20a or of the side plate 500. Thus, the manufacturing of the heat
exchanger can be simplified.
[0219] In FIG. 32, a longitudinal end portion of the side plate
500, which supports the core, is bent and is inserted into the
interior of the downstream side lower tank 411. Alternatively, a
longitudinal end portion of the tube 20a, which is located at the
lateral end of the core, may be bent and inserted into the interior
of the downstream side lower tank 411. With this construction, even
in the case where the portion of the communication passage forming
member 44 is placed laterally inward of the lateral ends of the
core, the longitudinal end portion of the tube 20a or of the side
plate 500 is not placed at the second communication passage 43.
Therefore, it is possible to reduce the flow resistance of the
refrigerant in the communication passage.
[0220] FIG. 33 shows the evaporator, which has the tube 20a, which
is placed at the lateral end of the core and does not conduct the
refrigerant therethrough. The tube 20a or the side plate 500, which
supports the core, has the longitudinal end portion, which is bent
and contacts the outer surface of the communication passage forming
member 44. With this construction, even in the case where the
portion of the communication passage forming member 44 is placed
laterally inward of the lateral ends of the core, it is possible to
eliminate the need for inserting the longitudinal end portion of
the tube 20a or of the side plate 500 into the interior of the
tank.
[0221] Now, modifications of the above embodiments will be
described.
[0222] In the above embodiments, the number of the flow passage
rows in the direction of the air flow (the Z-direction) is set to
be two. However, the present invention is not limited to this. For
example, the number of the flow passage rows in the direction of
the air flow (the Z-direction) may be alternatively set to be three
or more.
[0223] Furthermore, the core of the above embodiments may be
modified such that the outer fins between the tubes may be
eliminated from the core. Furthermore, the core of the above
embodiments may be modified such that projections are created (for
example by cutting) and bent at the tubes to project between the
tubes. In such a case where the core is the finless type, in which
the fines are eliminated between the tubes, or the type, in which
the fins are joined to only one of the adjacent tubes, a draining
performance of the condensed water, which is condensed on the outer
surface of the core, can be promoted. Therefore, the accurate
temperature measurement of the core is possible, and the good
response can be obtained.
[0224] Furthermore, in the above embodiments, the refrigerant is
the R134a refrigerant. However, the refrigerant of the present
invention is not limited to this type of refrigerant. Even when the
other refrigerant, such as the carbon dioxide refrigerant or the
R152 refrigerant, is used, the advantages similar to the above
described ones can be achieved. However, when the R134a refrigerant
is used, the above advantages are more prominent.
[0225] In the above embodiments, the evaporator is used in the
refrigeration cycle of the vehicle air conditioning system.
However, the present application is also equally application to a
heat exchanger in a refrigeration cycle of any other system, which
is other than the vehicle air conditioning system.
[0226] In the above embodiments, the upstream side and downstream
side header tanks are constructed such that the refrigerant is
supplied into or is outputted from the tubes at the interior of the
header tank. However, the location, at which the refrigerant is
supplied into or is outputted from the tubes, is not limited to the
interior of the tank. For example, the location, at which the
refrigerant is supplied into or is outputted from the tubes, may be
placed on the upstream side or downstream side of the interior of
the tank rather than placing it completely in the interior of the
tank.
[0227] Furthermore, in the above embodiments, the thickness Ta of
the downstream side flow passage row 21, which is measured in the
direction of the air flow, is set to be generally the same as the
thickness Th of the upstream side flow passage row 22, which is
measured in the direction of the air flow. Alternatively, the
thickness Ta of the downstream side flow passage row 21, which is
measured in the direction of the air flow, may be made larger than
the thickness Th of the upstream side flow passage row 22, which is
measured in the direction of the air flow. In this way, the cross
sectional area of the downstream side flow passage, at which the
dryness of the refrigerant is relatively large, is increased.
Therefore, the pressure loss of the refrigerant can be reduced in
the entire heat exchanger.
[0228] Furthermore, the evaporator of the above respective
embodiments includes the communicating means that communicates
between the interior of the furthermost downstream side header tank
11, which is furthermost from the flow inlet 51, and the interior
of the furthermost upstream side header tank 12, which is
furthermost from the flow outlet 52, and this communicating means
is placed at the location, which projects laterally or vertically
from the body of the core. In addition to this communication means,
it is possible to provide a communication passage, which
communicates between the interior of the downstream side header
tank 11 and the interior of the upstream side header tank 12.
[0229] Additional advantages and modifications will readily occur
to those skilled in the art. The invention in its broader terms is
therefore not limited to the specific details, representative
apparatus, and illustrative examples shown and described.
* * * * *