U.S. patent application number 13/884086 was filed with the patent office on 2013-09-19 for heat exchanger.
This patent application is currently assigned to DENSO CORPORATION. The applicant listed for this patent is Yoshiki Katoh. Invention is credited to Yoshiki Katoh.
Application Number | 20130240185 13/884086 |
Document ID | / |
Family ID | 46050623 |
Filed Date | 2013-09-19 |
United States Patent
Application |
20130240185 |
Kind Code |
A1 |
Katoh; Yoshiki |
September 19, 2013 |
HEAT EXCHANGER
Abstract
Refrigerant tubes each having a refrigerant side turning portion
for changing a flow direction of refrigerant, and cooling medium
tubes each having a cooling medium side turning portion for
changing a flow direction of coolant for an electric motor MG for
travelling are alternately stacked over each other between a
refrigerant header tank and a cooling medium header tank. An outer
fin is disposed in an outside air passage formed between the
refrigerant tube and the coolant tube adjacent to each other. The
refrigerant side turning portion is positioned closer to the
cooling medium header tank than the refrigerant header tank. The
cooling medium side turning portion is positioned closer to the
refrigerant side header tank than the cooling medium header
tank.
Inventors: |
Katoh; Yoshiki; (Chita-gun,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Katoh; Yoshiki |
Chita-gun |
|
JP |
|
|
Assignee: |
DENSO CORPORATION
Kariya-city, Aichi-pref.
JP
|
Family ID: |
46050623 |
Appl. No.: |
13/884086 |
Filed: |
November 7, 2011 |
PCT Filed: |
November 7, 2011 |
PCT NO: |
PCT/JP2011/006190 |
371 Date: |
May 8, 2013 |
Current U.S.
Class: |
165/140 |
Current CPC
Class: |
F28F 21/084 20130101;
F28F 2215/02 20130101; F28D 1/0476 20130101; F28D 7/16 20130101;
F28D 2021/0085 20130101; F28D 2021/0094 20130101; F28F 9/0212
20130101; F28F 2275/04 20130101; F28F 9/0214 20130101; F28F 1/128
20130101; F28D 1/0478 20130101; F28D 1/0426 20130101 |
Class at
Publication: |
165/140 |
International
Class: |
F28D 7/16 20060101
F28D007/16 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 9, 2010 |
JP |
2010-251119 |
Oct 24, 2011 |
JP |
2011-233083 |
Claims
1. A heat exchanger comprising: a first heat exchanging portion
including a plurality of first tubes through which a first fluid
flows, and a first tank extending in a direction of lamination of
the first tubes to collect or distribute the first fluid flowing
through the first tubes, the first heat exchanging portion being
adapted to exchange heat between the first fluid and a third fluid
flowing around the first tubes; and a second heat exchanging
portion including a plurality of second tubes through which a
second fluid flows, and a second tank extending in a direction of
lamination of the second tubes to collect or distribute the second
fluid flowing through the second tubes, the second heat exchanging
portion being adapted to exchange heat between the second fluid and
the third fluid flowing around the second tubes, wherein the first
tubes and the second tubes are disposed between the first tank and
the second tank, at least one of the first tubes is disposed
between the second tubes, at least one of the second tubes is
disposed between the first tubes, a space formed between the first
tube and the second tube defines a third fluid passage through
which the third fluid flows, an outer fin is disposed in the third
fluid passage, to promote heat exchange between both the heat
exchanging portions while enabling heat transfer between the first
fluid flowing through the first tubes and the second fluid flowing
through the second tubes, the first tube is provided with a first
turning portion for changing a flow direction of the first fluid,
the second tube is provided with a second turning portion for
changing a flow direction of the second fluid, the first turning
portion is positioned closer to the second tank than the first
tank, and the second turning portion is positioned closer to the
first tank than the second tank.
2. The heat exchanger according to claim 1, wherein a temperature
of the first fluid introduced into the first heat exchanging
portion is different from a temperature of the second fluid
introduced into the second heat exchanging portion, and the outer
fin is disposed in a space formed between the first and second
tubes adjacent to each other, between the adjacent first tubes, and
between adjacent second tubes.
3. The heat exchanger according to claim 1, wherein the first tube
and the second tube are fixed to both the first tank and the second
tank.
4. The heat exchanger according to claim 1, wherein when one fluid
with a higher temperature, of the first fluid introduced into the
first heat exchanging portion and the second fluid introduced into
the second heat exchanging portion is defined as a high-temperature
side fluid, when an upstream side portion of a high-temperature
side tube of the first tube and the second tube through which the
high-temperature fluid flows with respect to a corresponding one of
the first and second turning portions is defined as a
high-temperature side tube upstream portion, and when a downstream
side portion of the high-temperature side tube of the first tube
and the second tube through which the high-temperature fluid flows
with respect to the corresponding one of the first and second
turning portions is defined as a high-temperature side tube
downstream portion, the temperature of the third fluid is lower
than that of the high-temperature side fluid, and the
high-temperature side tube upstream portion of at least one of the
high-temperature side tubes is positioned on an upstream side in a
flow direction of the third fluid with respect to the
high-temperature side tube downstream portion.
5. The heat exchanger according to claim 4, wherein when one fluid
having a lower temperature, of the first fluid introduced into the
first heat exchanging portion and the second fluid introduced into
the second heat exchanging portion is defined as a low-temperature
side fluid, when an upstream side portion of a low-temperature side
tube of the first tube and the second tube through which the
low-temperature side fluid flows with respect to a corresponding
one of the first and second turning portions is defined as a
low-temperature side tube upstream portion, and when a downstream
side portion of the low-temperature side tube of the first tube and
the second tube through which the low-temperature fluid flows with
respect to the corresponding one of the first and second turning
portions is defined as a low-temperature side tube downstream
portion, the temperature of the third fluid is lower than that of
the low-temperature side fluid, and the low-temperature side tube
upstream portion of at least one of the low-temperature side tubes
is positioned on the upstream side in the flow direction of the
third fluid with respect to the low-temperature side tube
downstream portion.
6. The heat exchanger according to claim 1, wherein the temperature
of the third fluid is lower than that of one fluid having a higher
temperature, of the first fluid introduced into the first heat
exchanging portion and the second fluid introduced into the second
heat exchanging portion, and is higher than that of the other fluid
having a lower temperature.
7. The heat exchanger according to claim 1, wherein when an
upstream side portion of the first tube with respect to the first
turning portion is defined as a first tube upstream portion, when a
downstream side portion of the first tube with respect to the first
turning portion is defined as a first tube downstream portion, when
an upstream side portion of the second tube with respect to the
second turning portion is defined as a second tube upstream
portion, and when a downstream side portion of the second tube with
respect to the second turning portion is defined as a second tube
downstream portion, the first tube upstream portion and the second
tube upstream portion are arranged in a direction of lamination of
the first and second tubes, and the first tube downstream portion
and the second tube downstream portion are arranged in the
direction of lamination of the first and second tubes.
8. The heat exchanger according to claim 7, wherein the first tube
upstream portion and the second tube upstream portion are
positioned on the upstream side in the flow direction of the third
fluid with respect to the first tube downstream portion and the
second tube downstream portion.
9. The heat exchanger according to claim 7, wherein the first tubes
include an upstream side first tube group in which the first fluid
introduced into the first heat exchanging portion flows, and a
downstream side first tube group in which the first fluid flowing
from the upstream side first tube group flows to cause the first
fluid to flow out the first heat exchanging portion, the second
tubes include an upstream side second tube group in which the
second fluid introduced into the second heat exchanging portion
flows, and a downstream side second tube group in which the second
fluid flowing from the upstream side second tube group flows to
cause the second fluid to flow out the second heat exchanging
portion, and the first tube upstream portion and the second tube
upstream portion of the upstream side first tube group and the
upstream side second tube group are positioned on the upstream side
in the flow direction of the third fluid with respect to the first
tube downstream portion and the second tube downstream portion.
10. The heat exchanger according to claim 9, wherein the first tube
upstream portion and the second tube upstream portion of the
downstream side first tube group and the downstream side second
tube group are positioned on the downstream side in the flow
direction of the third fluid with respect to the first tube
downstream portion and the second tube downstream portion.
11. The heat exchanger according to claim 1, wherein the outer fin
is coupled to the first and second tubes, and provided with a
plurality of slits for locally weakening rigidity of the outer
fin.
12. The heat exchanger according to claim 1, wherein an area of a
refrigerant passage of an intermediate part of at least one of the
first turning portion and the second turning portion is larger than
an area of a fluid passage of each of a fluid inflow portion and a
fluid outflow portion of the one turning portion.
13. The heat exchanger according to claim 1, further comprising an
inner fin disposed within at least one of the first tube and the
second tube, to promote the heat exchange between the first fluid
or the second fluid, and the third fluid, wherein the inner fin has
an end protruding into an internal space of the first turning
portion or second turning portion.
14. The heat exchanger according to claim 1, wherein each of the
first tube and the second tube is made of a plate tube formed by
bonding a pair of plates.
15. The heat exchanger according to claim 1, wherein each of the
first tube and the second tube is formed by bending a flat tube
with a flat section in a direction perpendicular to the
longitudinal direction of the tube.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on and claims the benefit of
priority of Japanese Patent Applications No. 2010-251119 filed on
Nov. 9, 2010, and No. 2011-233083 filed on Oct. 24, 2011, the
disclosures of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a compound heat exchanger
that can exchange heat among three kinds of fluids.
BACKGROUND ART
[0003] Conventionally, compound heat exchangers have been
conventionally known, which can exchange heat among three kinds of
fluids. For example, Patent Document 1 discloses a compound heat
exchanger that can exchange heat between outdoor air (outside air)
and a refrigerant of a refrigeration cycle device, and between the
refrigerant and a coolant for cooling an engine.
[0004] Specifically, the heat exchanger disclosed in Patent
Document 1 includes a plurality of linear refrigerant tubes
laminated, each having both ends connected to refrigerant tanks for
collecting or distributing the refrigerant. The heat exchanger also
includes heat pipes, each having one end connected to a coolant
tank for circulation of the coolant, and disposed between the
laminated refrigerant tubes in parallel to the refrigerant tubes.
And, fins for promoting heat exchange are arranged in outside air
passages formed between the refrigerant tubes and the heat
pipes.
[0005] The refrigeration cycle device disclosed in Patent Document
1 employs such a compound heat exchanger as an evaporator for
evaporating refrigerant by absorbing heat of the outside air and
heat of the coolant (e.g., waste heat of an engine) in the
refrigerant. At this time, the waste heat of the engine transferred
from the heat pipes can be used to suppress frost formation of the
heat exchanger.
RELATED ART DOCUMENTS
Patent Document
[0006] [Patent Document 1] [0007] Japanese Unexamined Patent
Publication No. 11-157326
[0008] In order to achieve the heat exchange between the
refrigerant and the outside air, and the heat exchange between the
refrigerant and the coolant as mentioned above in the heat
exchanger of Patent Document 1, the refrigerant tank and the
coolant tank are adjacent to each other in the flow direction of
the outside air, and the heat pipes are curved near the coolant
tank, so that the heat pipes are arranged between the refrigerant
pipes extending linearly.
[0009] However, the arrangement of the refrigerant tank and the
coolant tank adjacent to each other in the flow direction of the
outside air leads to an increase in size of the entire heat
exchanger in the flow direction of the outside air. Further, the
heat exchanger of Patent Document 1 has to use the complicated
shaped heat pipes that curve near the coolant tank, thereby
resulting in low productivity of the heat exchanger.
DISCLOSURE OF THE INVENTION
[0010] The present invention has been made in view of the above
matters, and it is an object of the present invention to improve
the productivity of a heat exchanger which can exchange heat among
three kinds of fluids.
[0011] According to a first aspect of the present disclosure, a
heat exchanger includes: a first heat exchanging portion including
a plurality of first tubes through which a first fluid flows, and a
first tank extending in a direction of lamination of the first
tubes to collect or distribute the first fluid flowing through the
first tubes, the first heat exchanging portion being adapted to
exchange heat between the first fluid and a third fluid flowing
around the first tubes; and a second heat exchanging portion
including a plurality of second tubes through which a second fluid
flows, and a second tank extending in a direction of lamination of
the second tubes to collect or distribute the second fluid flowing
through the second tubes, the second heat exchanging portion being
adapted to exchange heat between the second fluid and the third
fluid flowing around the second tubes. The first tubes and the
second tubes are disposed between the first tank and the second
tank, at least one of the first tubes is disposed between the
second tubes, at least one of the second tubes is disposed between
the first tubes, a space formed between the first tube and the
second tube defines a third fluid passage through which the third
fluid flows, and an outer fin is disposed in the third fluid
passage to promote heat exchange between both the heat exchanging
portions while enabling heat transfer between the first fluid
flowing through the first tubes and the second fluid flowing
through the second tubes. In addition, the first tube is provided
with a first turning portion for changing a flow direction of the
first fluid, the second tube is provided with a second turning
portion for changing a flow direction of the second fluid, the
first turning portion is positioned closer to the second tank than
the first tank, and the second turning portion is positioned closer
to the first tank than the second tank.
[0012] Thus, the heat can be exchanged between the first fluid and
the third fluid via the first tubes and the outer fins. The heat
can also be exchanged between the second fluid and the third fluid
via the second tubes and the outer fins. The heat can further be
exchanged between the first fluid and the second fluid via the
outer fins. Accordingly, the heat exchange can be performed among
three kinds of fluids.
[0013] The first and second tubes are disposed between the first
and second tanks, and the third fluid passage is formed in a space
formed between the first tube and the second tube, so that the
first tank and the second tank are not arranged in the flow
direction of the third fluid. Thus, the entire heat exchanger can
be prevented from increasing in size in the flow direction of the
third fluid.
[0014] The first turning portion of the first tube is positioned
closer to the second tank than the first tank, and the second
turning portion of the second tube is positioned closer to the
first tank than the second tank, so that the connection of the
first tube to the first tank can have the same or equivalent shape
as the connection of the second tube to the second tank.
[0015] As a result, the heat exchanger of the present disclosure
can improve the productivity of the heat exchanger that can
exchange heat among three kinds of fluids without increase in size.
The term "three kinds of fluids" as used herein means not only
fluids with different properties or compositions, but also fluids
which differ in temperature or state, such as a gas phase or a
liquid phase, even when those fluids have the same properties or
components. Thus, the first to third fluids are not limited to
fluids with different properties or compositions.
[0016] According to a second aspect of the present disclosure, a
temperature of the first fluid introduced into the first heat
exchanging portion may be different from a temperature of the
second fluid introduced into the second heat exchanging portion,
and the outer fin may be disposed in a space formed between the
first and second tubes and the other first and second tubes
adjacent thereto.
[0017] When the first fluid introduced into the first heat
exchanger differs in temperature from the second fluid introduced
into the second heat exchanger, the thermal strain (amount of heat
expansion) generated in the first tube is different from that
generated in the second tube, which might change the size of the
first tube and second tube. In such a case, the outer fins promote
the heat exchange between the respective fluids, thereby reducing
the difference in temperature between the first fluid and the
second fluid to relieve (reduce) the difference in thermal strain
between the first tube and the second tube. As a result, the
breakdown of the heat exchanger can be suppressed.
[0018] The term "spaces formed between the first and second tubes
and the other first and second tubes adjacent thereto" as used
herein means spaces formed between a first tube and another first
tube or a second tube adjacent to the first tube, and between a
second tube and a first tube or another second tube adjacent to the
second tube.
[0019] The term "introduction" or "flow out" as used herein means
the movement of the refrigerant in the heat exchanger, and the term
"inflow" or "outflow" as used herein means the movement of the
refrigerant in each tube.
[0020] According to a third aspect of the invention disclosed
herein, each of the first tube and the second tube may be fixed to
both the first tank and the second tank.
[0021] Since the first tube and the second tube are fixed to both
the first and second tanks, the entire heat exchanger can have the
mechanical strength increased. Further, the outer fin disposed in
the third fluid passage provided between the first tube and the
second tube can be easily fixed firmly.
[0022] According to a fourth aspect of the present disclosure, when
one fluid with a higher temperature, of the first fluid introduced
into the first heat exchanging portion and the second fluid
introduced into the second heat exchanging portion is defined as a
high-temperature side fluid, when an upstream side portion of a
high-temperature side tube of the first tube and the second tube
through which the high-temperature fluid flows with respect to a
corresponding one of the first and second turning portions is
defined as a high-temperature side tube upstream portion, and when
a downstream side portion of the high-temperature side tube of the
first tube and the second tube through which the high-temperature
fluid flows with respect to the corresponding one of the first and
second turning portions is defined as a high-temperature side tube
downstream portion, the temperature of the third fluid may be lower
than that of the high-temperature side fluid, and the
high-temperature side tube upstream portion of at least one of the
high-temperature side tubes may be positioned on an upstream side
in a flow direction of the third fluid with respect to the
high-temperature side tube downstream portion.
[0023] Thus, the difference in temperature between the
high-temperature side fluid and the third fluid can be ensured on
the upstream side of the fluid flow in the high-temperature side
tube to increase the amount of heat dissipation. As a result, the
difference in temperature between the first fluid and the second
fluid can be reduced to relieve the difference in thermal strain
between the first tubes and the second tubes, and thereby it can
suppress the breakdown of the heat exchanger.
[0024] According to a fifth aspect of the present disclosure, when
one fluid having a lower temperature, of the first fluid introduced
into the first heat exchanging portion and the second fluid
introduced into the second heat exchanging portion is defined as a
low-temperature side fluid, when an upstream side portion of a
low-temperature side tube of the first tube and the second tube
through which the low-temperature side fluid flows with respect to
a corresponding one of the first and second turning portions is
defined as a low-temperature side tube upstream portion, and when a
downstream side portion of the low-temperature side tube of the
first tube and the second tube through which the low-temperature
fluid flows with respect to the corresponding one of the first and
second turning portions is defined as a low-temperature side tube
downstream portion, the temperature of the third fluid may be lower
than that of the low-temperature side fluid, and the
low-temperature side tube upstream portion of at least one of the
low-temperature side tubes may be positioned on the upstream side
in the flow direction of the third fluid with respect to the
low-temperature side tube downstream portion.
[0025] Thus, on the upstream side of the fluid flow in the
low-temperature side tube, the difference in temperature between
the low-temperature side fluid and the third fluid can be ensured
to increase the amount of heat dissipation. As a result, the
difference in temperature between the first fluid and the second
fluid can be reduced to relieve the difference in thermal strain
between the first tube and the second tube, which can suppress the
breakdown of the heat exchanger.
[0026] According to a sixth aspect of the present disclosure, the
temperature of the third fluid may be lower than that of one fluid
having a higher temperature, of the first fluid introduced into the
first heat exchanging portion and the second fluid introduced into
the second heat exchanging portion, and may be higher than that of
the other fluid having a lower temperature.
[0027] Thus, the temperature of a high-temperature side fluid of
the first and second fluids in the heat exchanger is decreased
while the temperature of a low-temperature side fluid is increased,
and thereby it can reduce the difference in temperature between the
first fluid and the second fluid. As a result, the difference in
thermal strain between the respective tubes can be relieved to
effectively suppress the breakdown of the heat exchanger.
[0028] According to a seventh aspect of the present disclosure,
when an upstream side portion of the first tube with respect to the
first turning portion is defined as a first tube upstream portion,
when a downstream side portion of the first tube with respect to
the first turning portion is defined as a first tube downstream
portion, when an upstream side portion of the second tube with
respect to the second turning portion is defined as a second tube
upstream portion, and when a downstream side portion of the second
tube with respect to the second turning portion is defined as a
second tube downstream portion, the first tube upstream portion and
the second tube upstream portion may be arranged in a direction of
lamination of the first and second tubes, and the first tube
downstream portion and the second tube downstream portion may be
arranged in the direction of lamination of the first and second
tubes.
[0029] Thus, the difference in temperature between the first fluid
flowing through the first tube and the second fluid flowing through
the second tube can be reduced to relieve the difference in thermal
strain between the first tube and the second tube.
[0030] According to an eighth aspect of the present disclosure, the
first tube upstream portion and the second tube upstream portion
may be positioned on the upstream side in the flow direction of the
third fluid with respect to the first tube downstream portion and
the second tube downstream portion.
[0031] When the first fluid introduced into the first heat
exchanging portion and the second fluid introduced into the second
heat exchanging portion have the temperature higher than that of
the third fluid, the difference in temperature between the first
and third fluids and the difference in temperature between the
second and third fluids can be ensured on the upstream side of the
fluid flow of the first tube and on the upstream side of the fluid
flow of the second tube to thereby increase the amount of heat
dissipation. As a result, the difference in thermal strain between
the first tube and the second tube can be relieved to thereby
suppress the breakdown of the heat exchanger.
[0032] According to a ninth aspect of the present disclosure, the
first tubes may include an upstream side first tube group in which
the first fluid introduced into the first heat exchanging portion
flows, and a downstream side first tube group in which the first
fluid flowing from the upstream side first tube group flows to
cause the first fluid to flow out the first heat exchanging
portion, the second tubes may include an upstream side second tube
group in which the second fluid introduced into the second heat
exchanging portion flows, and a downstream side second tube group
in which the second fluid flowing from the upstream side second
tube group flows to cause the second fluid to flow out the second
heat exchanging portion. In this case, the first tube upstream
portion and the second tube upstream portion of the upstream side
first tube group and the upstream side second tube group may be
positioned on the upstream side in the flow direction of the third
fluid with respect to the first tube downstream portion and the
second tube downstream portion.
[0033] When the first fluid introduced into the first heat
exchanging portion and the second fluid introduced into the second
heat exchanging portion have the temperature higher than that of
the third fluid, the difference in temperature between the first
and second fluids is reduced, while the differences in temperature
between the first and third fluids and between the second and third
fluids are ensured on the upstream sides of fluid flows of the
upstream side first and second tube groups. Thus, the amount of
heat dissipation can be increased. As a result, the difference in
thermal strain between the first tube and the second tube can be
relieved to thereby suppress the breakdown of the heat
exchanger.
[0034] According to a tenth aspect of the present disclosure, the
first tube upstream portion and the second tube upstream portion of
the downstream side first tube group and the downstream side second
tube group may be positioned on the downstream side in the flow
direction of the third fluid with respect to the first tube
downstream portion and the second tube downstream portion.
[0035] When the first fluid introduced into the first heat
exchanging portion and the second fluid introduced into the second
heat exchanger have the temperature higher than that of the third
fluid, the heat contained in the first fluid and the second fluid
can be sufficiently dissipated into the third fluid on the
downstream sides of fluid flows of the downstream side first and
second tube groups. As a result, the performance of the heat
exchanger can be improved.
[0036] According to an eleventh aspect of the present disclosure,
the outer fin may be bonded to the first and second tubes, and may
be provided with a plurality of slits for locally weakening
rigidity of the outer fin.
[0037] Thus, when the difference in thermal strain between the
first tube and the second tube occurs, the slits of the outer fins
can absorb the stress acting on each tube. Further, the slits
provided in the outer fins can also suppress the breakdown of the
heat exchanger within a partial range even with the difference in
thermal strain between the respective tubes.
[0038] According to a twelfth aspect of the present disclosure, an
area of a refrigerant passage of an intermediate part of at least
one of the first turning portion and the second turning portion may
be larger than an area of a fluid passage of each of a fluid inflow
portion and a fluid outflow portion of the one turning portion.
[0039] Thus, when the first fluid passes through the first turning
portion, or when the second fluid passes through the second turning
portion, the loss in pressure can be reduced.
[0040] According to a thirteenth aspect of the present disclosure,
an inner fin may be disposed within at least one of the first tube
and the second tube, to promote the heat exchange between the first
fluid or the second fluid, and the third fluid. In this case, the
inner fin may have an end protruding into an internal space of the
first turning portion or second turning portion.
[0041] Thus, the end of each inner fin protrudes into the internal
space of the first turning portion or second turning portion,
thereby preventing the failure of connection between the inner fins
and the inner peripheral surfaces of the first tube and the second
tube.
[0042] According to a fourteenth aspect of the present disclosure,
each of the first tube and the second tube may be made of a plate
tube formed by bonding a pair of plates. Alternatively, according
to a fifteenth aspect of the present disclosure, each of the first
tube and the second tube may be formed by bending a flat tube with
a flat section in a direction perpendicular to the longitudinal
direction of the tube.
BRIEF DESCRIPTION OF DRAWINGS
[0043] The above and other objects, structures, and advantages of
the present invention will become apparent from the following
detailed description of the invention, when taken in conjunction
with the accompanying drawings, which respectively show:
[0044] FIG. 1 is an entire configuration diagram showing
refrigerant flow paths of a heat pump cycle in a heating operation
according to a first embodiment;
[0045] FIG. 2 is an entire configuration diagram showing
refrigerant flow paths of the heat pump cycle in a defrosting
operation in the first embodiment;
[0046] FIG. 3 is an entire configuration diagram showing
refrigerant flow paths of the heat pump cycle in a waste heat
recovering operation in the first embodiment;
[0047] FIG. 4 is an entire configuration diagram showing
refrigerant flow paths of the heat pump cycle in a cooling
operation in the first embodiment;
[0048] FIG. 5 is a perspective view of the contour of a heat
exchanger in the first embodiment;
[0049] FIG. 6(a) is a front view of a tube for refrigerant (tube
for a cooling medium) in the first embodiment, and FIG. 6(b) is a
side view of the tube for refrigerant in FIG. 6(a);
[0050] FIG. 7 is a cross-sectional view taken along the line
VII-VII of FIG. 6(a);
[0051] FIG. 8 is a cross-sectional view taken along the line
VIII-VIII of FIG. 6(a);
[0052] FIG. 9 is a cross-sectional view taken along the line IX-IX
of FIG. 6(a);
[0053] FIG. 10 is a schematic perspective view for explaining the
flows of refrigerant and coolant in the heat exchanger of the first
embodiment;
[0054] FIG. 11 is a schematic partially exploded perspective view
of the heat exchanger in the first embodiment;
[0055] FIG. 12 is a perspective view of the contour of a heat
exchanger according to a second embodiment;
[0056] FIG. 13 is a schematic perspective view for explaining the
flows of refrigerant and coolant in the heat exchanger of the
second embodiment;
[0057] FIG. 14 is a schematic partially-exploded perspective view
of the heat exchanger in the second embodiment;
[0058] FIG. 15(a) is a front view of a tube for refrigerant (tube
for a cooling medium) of the heat exchanger according to a third
embodiment, and FIG. 15(b) is a side view of the tube for
refrigerant shown in FIG. 15(a);
[0059] FIG. 16 is an entire configuration diagram showing
refrigerant flow paths of the heat pump cycle in a waste heat
recovering operation according to a fourth embodiment;
[0060] FIG. 17 is a perspective view of the contour of a heat
exchanger according to a fifth embodiment;
[0061] FIG. 18 is a schematic appearance perspective view for
explaining the flows of refrigerant and coolant in the heat
exchanger of the fifth embodiment;
[0062] FIGS. 19(a), 19(b), 19(c), and 19(d) are schematic
cross-sectional views of heat exchangers in the longitudinal
direction of header tanks according to other embodiments;
[0063] FIG. 20 is an explanatory diagram for explaining the
influences of differences in temperature between the refrigerant
and coolant in each tube due to differences in structure between
respective heat exchangers;
[0064] FIG. 21 is a schematic partially perspective view of a heat
exchanger according to another embodiment; and
[0065] FIGS. 22(a), 22(b), and 22(c) are explanatory diagrams for
explaining outer fins according to another embodiment.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0066] Embodiments of the invention will be described below based
on the accompanying drawings. The same or equivalent parts through
the following embodiments are indicated by the same reference
characters in the figures.
First Embodiment
[0067] Referring to FIGS. 1 to 11, a first embodiment of the
present invention will be described below. In this embodiment, a
heat exchanger 16 of the invention is applied to a heat pump cycle
10 for adjusting the temperature of air to be blown into the
interior of a vehicle in a vehicle air conditioner 1. FIGS. 1 to 4
are entire configuration diagrams of the vehicle air conditioner 1
in this embodiment. The vehicle air conditioner 1 is applied to the
so-called hybrid car, which can obtain a driving force for
traveling from an internal combustion engine (engine) and an
electric motor MG for traveling.
[0068] The hybrid car can perform switching between a traveling
state in which the vehicle travels obtaining the driving force from
both engine and electric motor MG for traveling by operating or
stopping the engine according to a traveling load on the vehicle or
the like, and another traveling state in which the vehicle travels
obtaining the driving force only from the electric motor MG for
traveling by stopping the engine. Thus, the hybrid car can improve
the fuel efficiency as compared to normal cars obtaining a driving
force for traveling only from the engine.
[0069] The heat pump cycle 10 in the vehicle air conditioner 1 is
an evaporation compression refrigeration cycle that serves to heat
or cool the air in the vehicle compartment to be blown into the
vehicle interior as a space of interest for air conditioning. That
is, the heat pump cycle 10 can switch between refrigerant flow
paths to thereby perform a heating operation (heater operation) and
a cooling operation (cooler operation). The heating operation is
performed to heat the vehicle interior by heating the air in the
vehicle compartment as a fluid of interest for heat exchange. The
cooling operation is performed to cool the vehicle interior by
cooling the air in the vehicle compartment.
[0070] Then, the heat pump cycle 10 can also perform a defrosting
operation and a waste heat recovering operation. The defrosting
operation is performed to melt and remove frost formed at an
outdoor heat exchanging portion 60 of the heat exchanger 16 in the
heating operation by changing the flow rate of the refrigerant,
coolant, or outside air flowing through the heat exchanger 16 as
will be described later. The waste heat recovering operation is
performed to absorb heat of the electric motor MG for traveling in
the refrigerant as the external heat source in the heating
operation. In the entire configuration diagrams of the heat pump
cycle 10 shown in FIGS. 1 to 4, the flows of refrigerant in the
respective operations are designated by a solid arrow.
[0071] The heat pump cycle 10 of this embodiment employs a normal
flon-based refrigerant as the refrigerant, and forms a subcritical
refrigeration cycle whose high-pressure side refrigerant pressure
does not exceed the critical pressure of the refrigerant.
Refrigerating machine oil for lubricating a compressor 11 is mixed
into the refrigerant, and a part of the refrigerating machine oil
circulates through the cycle together with the refrigerant.
[0072] First, the compressor 11 is positioned in an engine room,
and is to suck, compress, and discharge the refrigerant in the heat
pump cycle 10. The compressor is an electric compressor which
drives a fixed displacement compressor 11a having a fixed discharge
capacity by use of an electric motor 11b. Specifically, various
types of compression mechanisms, such as a scroll type compression
mechanism, or a vane compression mechanism, can be employed as the
fixed displacement compressor 11a.
[0073] The electric motor 11b is one whose operation (number of
revolutions) is controlled by a control signal output from an air
conditioning controller to be described later. The motor 11b may
use either an AC motor or a DC motor. The control of the number of
revolutions of the motor changes a refrigerant discharge capacity
of the compressor 11. Thus, in this embodiment, the electric motor
11b serves as discharge capacity changing means of the compressor
11.
[0074] A refrigerant discharge port of the compressor 11 is coupled
to a refrigerant inlet side of an indoor condenser 12 as a
user-side heat exchanger. The indoor condenser 12 is disposed in a
casing 31 of an indoor air conditioning unit 30 of the air
conditioner 1 for the vehicle. The indoor condenser is a heat
exchanger for heating that exchanges heat between a
high-temperature and high-pressure refrigerant flowing therethrough
and the air in the vehicle compartment having passed through an
indoor evaporator 20 to be described later. The detailed structure
of the indoor air conditioning unit 30 will be described later.
[0075] A fixed throttle 13 for heating is coupled to a refrigerant
outlet side of the indoor condenser 12. The fixed throttle 13
serves as decompression means for the heating operation that
decompresses and expands the refrigerant flowing from the indoor
condenser 12 in the heating operation. The fixed throttle 13 for
heating can use an orifice, a capillary tube, and the like. The
outlet side of the fixed throttle 13 for heating is coupled to the
refrigerant inlet side of the outdoor heat exchanging portion 60 of
the compound heat exchanger 16.
[0076] A bypass passage 14 for the fixed throttle is coupled to the
refrigerant outlet side of the indoor condenser 12. The bypass
passage 14 causes a refrigerant flowing from the indoor condenser
12 to bypass the fixed throttle 13 for heating and to guide the
refrigerant into the outdoor heat exchanging portion 60 of the heat
exchanger 16. An opening/closing valve 15a for opening and closing
the bypass passage 14 for the fixed throttle is disposed in the
bypass passage 14 for the fixed throttle. The opening/closing valve
15a is an electromagnetic valve whose opening and closing
operations are controlled by a control voltage output from the air
conditioning controller.
[0077] The loss in pressure caused when the refrigerant passes
through the opening/closing valve 15a is extremely small as
compared to the loss in pressure caused when the refrigerant passes
through the fixed throttle 13. Thus, when the opening/closing valve
15a is opened, the refrigerant flowing out of the indoor condenser
12 flows into the outdoor heat exchanging portion 60 of the heat
exchanger 16 via the bypass passage 14 for the fixed throttle. In
contrast, when the opening/closing valve 15a is closed, the
refrigerant flows into the outdoor heat exchanging portion 60 of
the heat exchanger 16 via the fixed throttle 13 for heating.
[0078] Thus, the opening/closing valve 15a can switch between the
refrigerant flow paths of the heat pump cycle 10. The
opening/closing valve 15a of this embodiment serves as refrigerant
flow path switching means. Alternatively, as such a refrigerant
flow path switching means, an electric three-way valve or the like
may be provided for switching between a refrigerant circuit for
coupling the outlet side of the indoor condenser 12 to the inlet
side of the fixed throttle 13 for heating, and another refrigerant
circuit for coupling the outlet side of the indoor condenser 12 to
the inlet side of the bypass passage 14 for the fixed throttle.
[0079] The heat exchanger 16 is disposed in an engine room. The
outdoor heat exchanging portion 60 of the heat exchanger 16 is a
heat exchanging portion for exchanging heat between the
low-pressure refrigerant flowing therethrough and an outside air
blown from a blower fan 17. Further, the outdoor heat exchanging
portion 60 serves as a heat exchanging portion for evaporation that
evaporates the low-pressure refrigerant to exhibit a heat
absorption effect in the heating operation, and also as a heat
exchanging portion for heat dissipation that dissipates heat from
the high-pressure refrigerant in the cooling operation.
[0080] The blower fan 17 is an electric blower whose operating
ratio, that is, whose number of revolutions (volume of air) is
controlled by a control voltage output from the air conditioning
controller. The heat exchanger 16 of this embodiment is integral
with a radiator 70 for exchanging heat between the outside air
blown from the blower fan 17 and the coolant circulating through
the above outdoor heat exchanging portion 60 and a coolant
circulation circuit 40 for cooling the electric motor MG for
traveling.
[0081] The blower fan 17 of this embodiment serves as outdoor
blowing means for blowing the outside air toward both the outdoor
heat exchanging portion 60 of the heat exchanger 16 and the
radiator 70. The details structures of the compound heat exchanger
16 including the coolant circulation circuit 40, the outdoor heat
exchanging portion 60, and the radiator 70 which are integral with
each other will be described in detail below.
[0082] The outlet side of the outdoor heat exchanging portion 60 of
the heat exchanger 16 is coupled to an electric three-way valve
15b. The three-way valve 15b has its operation controlled by a
control voltage output from the air conditioning controller. The
three-way valve 15b serves as the refrigerant flow path switching
means together with the above opening/closing valve 15a.
[0083] More specifically, in the heating operation, the three-way
valve 15b performs switching to the refrigerant flow path for
coupling the outlet side of the outdoor heat exchanger 19 to the
inlet side of an accumulator 18 to be described later. In contrast,
in the cooling operation, the three-way valve 15b performs
switching to the refrigerant flow path for coupling the outlet side
of the outdoor heat exchanging portion 60 of the heat exchanger 16
to the inlet side of a fixed throttle 19 for cooling. The fixed
throttle 19 for cooling serves as decompression means for the
cooling operation for decompressing and expanding the refrigerant
flowing from the outdoor heat exchanging portion 60 in the cooling
operation. The fixed throttle 19 has the same basic structure as
that of the above fixed throttle 13 for heating.
[0084] The outlet side of the fixed throttle 19 for cooling is
coupled to the refrigerant inlet side of the indoor evaporator 20.
The indoor evaporator 20 is disposed on the upstream side of the
air flow with respect to the indoor condenser 12 in the casing 31
of the indoor air conditioning unit 30. The indoor evaporator 20 is
a heat exchanger for cooling that exchanges heat between the air in
the vehicle compartment and the refrigerant flowing therethrough to
thereby cool the air within the vehicle interior.
[0085] A refrigerant outlet side of the indoor evaporator 20 is
coupled to an inlet side of the accumulator 18. The accumulator 18
is a gas-liquid separator for the low-pressure side refrigerant
that separates the refrigerant flowing thereinto into liquid and
gas phases, and which stores therein the excessive refrigerant
within the cycle. A vapor-phase refrigerant outlet of the
accumulator 18 is coupled to a suction side of the compressor 11.
Thus, the accumulator 18 serves to suppress the suction of the
liquid-phase refrigerant into the compressor 11 to thereby prevent
the compression of the liquid in the compressor 11.
[0086] Next, the indoor air conditioning unit 30 will be described
below. The indoor air conditioning unit 30 is disposed inside a
gauge board (instrument panel) at the forefront of the vehicle
compartment. The unit 30 accommodates in the casing 31 forming an
outer envelope, a blower 32, the above-mentioned indoor condenser
12, and the indoor evaporator 20.
[0087] The casing 31 forms an air passage for flowing the air in
the vehicle compartment, blown into the vehicle interior. The
casing 31 is formed of resin (for example, polypropylene) having
some degree of elasticity, and excellent strength. An
inside/outside air switch 33 for switching between the air (inside
air) in the vehicle interior and the outside air is disposed on the
most upstream side of the vehicle-interior air flow in the casing
31.
[0088] The inside/outside air switch 33 is provided with the inside
air inlet for introducing the inside air into the casing 31, and
the outside air inlet for introducing the outside air thereinto. An
inside/outside air switching door is positioned inside the
inside/outside air switch 33 to continuously adjust the opening
areas of the inside air inlet and the outside air inlet to thereby
change the ratio of volume of the inside air to the outside
air.
[0089] The blower 32 for blowing the air sucked via the
inside/outside air switch 33 into the vehicle interior is disposed
on the downstream side of the air flow of the inside/outside air
switch 33. The blower 32 is an electric blower which includes a
centrifugal multiblade fan (sirocco fan) driven by an electric
motor, and whose number of revolutions (volume of air) is
controlled by a control voltage output from the air conditioning
controller.
[0090] The indoor evaporator 20 and the indoor condenser 12 are
disposed on the downstream side of the air flow of the blower 32 in
that order with respect to the flow of the air in the vehicle
interior. In short, the indoor evaporator 20 is disposed on the
upstream side in the flow direction of the air in the vehicle
compartment with respect to the indoor condenser 12.
[0091] An air mix door 34 is disposed on the downstream side of the
air flow in the indoor evaporator 20 and on the upstream side of
the air flow in the indoor condenser 12. The air mix door 34
adjusts the rate of volume of the air passing through the indoor
condenser 12 among the air having passed through the indoor
evaporator 20. A mixing space 35 is provided on the downstream side
of the air flow in the indoor condenser 12 so as to mix the air
exchanging heat with the refrigerant and heated at the indoor
condenser 12, and the air bypassing the indoor condenser 12 and not
heated.
[0092] Air outlets for blowing the conditioned air mixed in the
mixing space 35, into the vehicle interior as a space of interest
to be cooled are disposed on the most downstream side of the air
flow in the casing 31. Specifically, the air outlets (not shown)
include a face air outlet for blowing the conditioned air toward
the upper body of a passenger in the vehicle compartment, a foot
air outlet for blowing the conditioned air toward the foot of the
passenger, and a defroster air outlet for blowing the conditioned
air toward the inner side of a front glass of the vehicle.
[0093] The air mix door 34 adjusts the rate of volume of air
passing through the indoor condenser 12 to thereby adjust the
temperature of conditioned air mixed in the mixing space 35, thus
controlling the temperature of the conditioned air blown from each
air outlet. That is, the air mix door 34 serves as temperature
adjustment means for adjusting the temperature of the conditioned
air blown into the vehicle interior.
[0094] In short, the air mix door 34 serves as heat exchanging
amount adjustment means for adjusting the amount of heat to be
exchanged between the air in the vehicle interior and the
refrigerant discharged from the compressor 11 in the indoor
condenser 12 serving as the user-side heat exchanger. The air mix
door 34 is driven by a servo motor (not shown) whose operation is
controlled based on the control signal output from the air
conditioning controller.
[0095] The face air outlet, foot air outlet, and defroster air
outlet have, at the respective upstream sides of the air flows
thereof, a face door for adjusting an opening area of the face air
outlet, a foot door for adjusting an opening area of the foot air
outlet, and a defroster door for adjusting an opening area of the
defroster air outlet, respectively (all doors being not shown).
[0096] The face door, foot door, and defroster door serve as air
outlet mode switching means for switching among air outlet modes.
The doors are driven by a servo motor (not shown) whose operation
is controlled based on a control signal output from the air
conditioning controller via a link mechanism or the like.
[0097] Next, the coolant circulation circuit 40 will be described
below. The coolant circulation circuit 40 is a cooling medium
circulation circuit for cooling the electric motor MG for traveling
by allowing the coolant (for example, ethylene glycol aqueous
solution) as a cooling medium (heat medium) to circulate through a
coolant passage formed in the above electric motor MG for
traveling, which is one of the vehicle-mounted devices generating
heat in operation.
[0098] The coolant circulation circuit 40 is provided with a
coolant pump 41, an electric three-way valve 42, the radiator 70 of
the compound heat exchanger 16, and a bypass passage 44 for
allowing the coolant to flow bypassing the radiator 70.
[0099] The coolant pump 41 is an electric pump for squeezing the
coolant into a coolant passage formed within the electric motor MG
for traveling in the coolant circulation circuit 40, and whose
number of revolutions (flow rate) is controlled by a control signal
output from the air conditioning controller. Thus, the coolant pump
41 serves as cooling capacity adjustment means for adjusting the
cooling capacity by changing the flow rate of the coolant for
cooling the electric motor MG for traveling.
[0100] The three-way valve 42 switches between a cooling medium
circuit for flowing the coolant into a radiator 70 by connecting
the inlet side of the coolant pump 41 to the outlet side of the
radiator 70, and another cooling medium circuit for flowing the
coolant to bypass the radiator 70 by connecting the inlet side of
the coolant pump 41 to the outlet side of the bypass passage 44.
The three-way valve 42 whose operation is controlled by a control
voltage output from the air conditioning controller serves as
circuit switching means for switching between the cooling medium
circuits.
[0101] That is, the coolant circulation circuit 40 of this
embodiment can perform switching between one cooling medium circuit
for circulation of the coolant from the coolant pump 41, to the
electric motor MG for travelling, the bypass passage 44, and the
coolant pump 41 in that order as illustrated by a dashed arrow of
FIG. 1 or the like, and another cooling medium circuit for
circulation of the coolant from the coolant pump 41, to the
electric motor MG for traveling, the radiator 70, and the coolant
pump 41 in that order as illustrated by a dashed arrow of FIG. 2 or
the like.
[0102] Thus, when the three-way valve 42 performs switching to the
cooling medium circuit for allowing the coolant to bypass the
radiator 70 during the operation of the electric motor MG for
traveling, the coolant has its temperature increased without
dissipating its heat into the radiator 70. That is, when the
three-way valve 42 performs switching to the cooling medium circuit
for allowing the coolant to bypass the radiator 70, the heat (heat
generated) contained in the electric motor MG for traveling is
stored in the coolant.
[0103] In contrast, when the three-way valve 42 performs switching
to the cooling medium circuit for allowing the coolant to pass
through the radiator 70 during the operation of the electric motor
MG for traveling, the coolant flows into the radiator 70 and then
exchanges heat with the outside air blown from the blower fan 17.
The heat exchanger 16 of this embodiment allows the coolant flowing
into the radiator 70 to exchange heat with not only the outside
air, but also the refrigerant flowing through the outdoor heat
exchanging portion 60.
[0104] Next, the compound heat exchanger 16 of this embodiment will
be described in detail using FIGS. 5 to 11. FIG. 5 shows a
perspective view of the contour of the heat exchanger 16 of this
embodiment. FIG. 6(a) shows a front view of a tube 61 for
refrigerant (tube 71 for a cooling medium) of the outdoor heat
exchanging portion 60 (radiator 70) in the first embodiment. FIG.
6(b) shows a side view of the tube of FIG. 6(a). FIG. 7 shows an
enlarged cross-sectional view taken along the line VII-VII of FIG.
6(a). FIG. 8 shows a cross-sectional view taken along the line
VIII-VIII of FIG. 6(a). FIG. 9 shows an enlarged cross-sectional
view taken along the line IX-IX of FIG. 6(a). FIG. 10 shows a
schematic perspective view for explaining the flows of refrigerant
and coolant in the heat exchanger 16.
[0105] As shown in FIG. 5, the outdoor heat exchanging portion 60
and the radiator 70 of the heat exchanger 16 includes a plurality
of tubes (61 and 71) for flowing the refrigerant or coolant
therethrough, and tanks (62 and 72) for collection and distribution
disposed on the end side of each of the tubes in the longitudinal
direction and adapted to collect and distribute the refrigerant or
coolant flowing through the tubes, which forms the so-called tank
and tube heat exchanger structure.
[0106] Specifically, the outdoor heat exchanging portion 60
includes a plurality of refrigerant tubes 61 for allowing the
refrigerant as a first fluid to flow therethrough, and a
refrigerant side header tank 62 extending in the lamination
direction of the tubes 61 to collect or distribute the refrigerant
flowing through the refrigerant tubes 61. The outdoor heat
exchanging portion 60 is a heat exchanging portion for exchanging
heat between the refrigerant flowing through the tubes 61 and air
(outside air blown from the blower fan 17) as a third fluid flowing
through around the refrigerant tubes 61.
[0107] In contrast, the radiator 70 includes a plurality of cooling
medium tubes 71 for allowing the coolant as a second fluid to flow
therethrough, and a cooling medium side header tank 72 extending in
the lamination direction of the tubes 71 to collect or distribute
the coolant flowing through the tubes 71. The radiator 70 is a heat
exchanging portion for exchanging heat between the coolant flowing
through the tubes 71 and air (outside air blown from the blower fan
17) flowing around the tubes 71.
[0108] In this embodiment as shown in FIGS. 6(a) and 6(b), each of
the refrigerant tube 61 and the cooling medium tube 71 employs the
so-called plate tube which is formed by bonding a pair of plates
61a and 61b (71a and 71b) with concave and convex portions on one
surface of each plate so as to align the center of one plate with
that of the other. The plates 61a and 61b (71a and 71b) are formed
of metal with excellent heat conductivity (aluminum alloy in this
embodiment).
[0109] The refrigerant tubes 61 and the cooling medium tubes 71 in
this embodiment have the same basic structure. FIGS. 6(a) and 6(b)
illustrate the refrigerant tube 61 while components of the cooling
medium tube 71 corresponding to components of the refrigerant tube
61 are indicated by respective reference numerals within
parentheses.
[0110] As shown in FIG. 5, the refrigerant tubes 61 and the cooling
medium tubes 71 extend in the direction that connect the
refrigerant side header tank 62 with the cooling medium side header
tank 72 to be described later, and are disposed between the
refrigerant side header tank 62 and the cooling medium side header
tank 72. In short, the refrigerant side header tank 62 is
positioned on one end side of each of the refrigerant tube 61 and
the cooling medium tube 71 in the longitudinal direction. The
cooling medium side header tank 72 is positioned on the other end
side of each of the refrigerant tube 61 and the cooling medium tube
71 in the longitudinal direction.
[0111] Each of the refrigerant tube 61 and the cooling medium tube
71 has one end in the longitudinal direction fixed to the
refrigerant side header tank 62, and the other end in the
longitudinal direction fixed to the cooling medium side header tank
72.
[0112] As shown in FIGS. 6(a) and 6(b), the refrigerant tube 61
extends in the longitudinal direction of the refrigerant tube 61
(in the direction perpendicular to the flow direction of outside
air blown from the blower fan 17). As shown in the cross-sectional
view of FIG. 7, refrigerant flow paths 61c with a flat section are
arranged in two lines in the flow direction A of the outside air
blown from the blower fan 17. Thus, the outer surface of a part
forming the refrigerant flow path 61c of the refrigerant tubes 61
is a flat surface 61d expanding in parallel to the flow direction
of the outside air blown from the blower fan 17.
[0113] As shown in the cross-sectional view of FIG. 8, the end of
each of both refrigerant flow paths 61c arranged in two lines on
the refrigerant side header tank 62 side is externally opened at
the end of the refrigerant tube 61. In this embodiment, the
refrigerant side header tank 62 is placed on the opened end of the
refrigerant flow path 61c, so that both the refrigerant flow paths
61c are in communication with the internal space of the refrigerant
side header tank 62.
[0114] In contrast, as shown in the cross-sectional view of FIG. 9,
the other end of each of both refrigerant flow paths 61c arranged
in two lines on the cool medium side header tank 72 side is not
externally opened to the outside of the refrigerant tube 61, and
the refrigerant flow paths 61c in two lines are connected together
by a refrigerant side turning portion 61e. In this way, the
internal space of the cooling medium side header tank 72 is not in
communication with the refrigerant tube 61, so that the two-lined
refrigerant flow paths 61c are in communication with each
other.
[0115] Thus, in the refrigerant tube 61 of this embodiment, the
refrigerant side turning portion 61e is positioned closer to the
cooling medium side header tank 72 than the refrigerant side header
tank 62. As indicated by the solid arrow of FIG. 10, the
refrigerant flowing into one of the refrigerant flow paths 61c
arranged in two lines from the refrigerant side header tank 62 has
its flow direction reversed at the refrigerant side turning portion
61e, and flows into the other refrigerant flow path 61c to return
to the refrigerant side header tank 62.
[0116] An area of a refrigerant passage of the refrigerant side
turning point 61e is larger than that of a refrigerant passage of
the refrigerant flow path 61c. That is, the area of the refrigerant
passage of an intermediate part of the refrigerant side turning
portion 61e is larger than that of each of a refrigerant inflow
part and a refrigerant outflow part of the refrigerant side turning
portion 61e connected to the refrigerant flow path 61c. The
refrigerant passage area is defined as a sectional area
perpendicular to the flow direction of the refrigerant.
[0117] An enlarging portion 61f is provided for enlarging the
refrigerant passage area of the refrigerant flow path 61c, on the
other end of the refrigerant flow path 61c of the refrigerant tube
61 opposite to the refrigerant side turning point 61e. Both
refrigerant flow paths 61c are in communication with the internal
space of the refrigerant side header tank 62 via the enlarging
portion 61f. The enlarging portion 61f is formed to enlarge a
surface area of the inside of the refrigerant tube 61 to thereby
improve the pressure resistance.
[0118] An inner fin 65 for promoting the heat exchange between the
refrigerant and the outside air blown from the blow fan 17 is
disposed within the refrigerant flow path 61c of the refrigerant
tube 61. The inner fin 65 is formed by bending a thin metal plate
in a wave shape. As shown in FIGS. 8 and 9, the inner fin 65 has
both ends in the longitudinal direction protruding into the
internal space of the enlarging portion 61f and the refrigerant
side turning portion 61e, respectively.
[0119] In the cooling medium tube 71, like the refrigerant tube 61,
cooling medium flow paths 71c with a flat section are arranged in
two lines in the flow direction A of the outside air blown from the
blower fan 17. Thus, the outer surface of a part forming the
cooling medium flow path 71c of the cooling medium tube 71 is a
flat surface 71d expanding in parallel to the flow direction of the
outside air blown from the blower fan 17.
[0120] Each cooling medium flow path 71c of the cooling medium tube
71 has one end on the cooling medium side header tank 72 side in
communication with the internal space of the cooling medium side
header tank 72. The other ends of both cooling medium flow paths
71c on the refrigerant header tank 62 side are connected to the
cooling medium side turning portion 71e having the same structure
as that of the refrigerant side turning portion 61e.
[0121] Thus, in the cooling medium tube 71, the cooling medium side
turning portion 71e is positioned closer to the refrigerant side
header tank 62 than the cooling medium side header tank 72. As
indicated by the dashed arrow of FIG. 10, the refrigerant flowing
into one of the cooling medium flow paths 71c arranged in two lines
from the cooling medium side header tank 72 has its flow direction
reversed at the cooling medium side turning portion 71e, and flows
into the other refrigerant flow path 71c to return to the cooling
medium side header tank 72.
[0122] An inner fin 75 for promoting the heat exchange between the
coolant and the outside air blown from the blow fan 17 is disposed
within the cool medium flow path 71c of the cool medium tube 71.
The inner fin 75 has the same structure as that of the inner fin 65
disposed in the refrigerant flow path 61c. The inner fin 75 has
both ends in the longitudinal direction protruding into the
internal space of the enlarging portion 71f and the cooling medium
side turning portion 71e, respectively.
[0123] In the refrigerant tube 61 and the cooling medium tube 71,
the flat surfaces 61d and 71d of the outer surfaces of the tubes
are laminated in parallel with a predetermined distance
therebetween. That is, the refrigerant tube 61 is disposed between
the cooling medium tubes 71. Conversely, the cooling medium tube 71
is disposed between the refrigerant tubes 61.
[0124] A space formed between the refrigerant tube 61 and the
cooling medium tube 71 forms an outside air passage 16a (third
fluid passage) for allowing the outside air blown from the blower
fan 17 to flow therethrough.
[0125] In the outside air passage 16a, an outer fin 50 is disposed
in connection with the flat surface 61d of the refrigerant tube 61
and the flat surface 71d of the cooling medium tube 71 which are
opposed to each other. The outer fin 50 can promote the heat
exchange between the outside air and the refrigerant in the outdoor
heat exchanging portion 60, and the heat exchange between the
outside air and the coolant in the radiator 70. Further, the outer
fins 50 enable heat transfer between the refrigerant flowing
through the refrigerant tube 61 and the coolant flowing through the
cooling medium tube 71.
[0126] The outer fin 50 for use is a corrugated fin formed by
bending a thin metal plate in a wave shape. In this embodiment, the
outer fin 50 is coupled to both the refrigerant tube 61 and the
cooling medium tube 71, which enables the heat transfer between the
refrigerant tube 61 and the cooling medium tube 71.
[0127] Next, the detailed structures of the refrigerant tube 61,
the cooling medium tube 71, the refrigerant side header tank 62,
and the cooling medium side header tank 72 will be described below
with reference to FIG. 11. FIG. 11 shows a schematic partially
exploded perspective view of the heat exchanger 16. For easy
understanding, FIG. 11 omits the illustration of the outer fin
50.
[0128] As shown in FIG. 11, each refrigerant tube 61 includes a
refrigerant tube upstream portion 611 located on the upstream side
of the refrigerant side turning portion 61e, and a refrigerant tube
downstream portion 612 located on the downstream side of the
refrigerant side turning portion 61e. That is, the refrigerant tube
61 of this embodiment is composed of the refrigerant tube upstream
portion 611, the refrigerant side turning portion 61e, and the
refrigerant tube downstream portion 612. In the refrigerant tube 61
of this embodiment, the refrigerant tube upstream portion 611 is
disposed on the downstream side in the flow direction A of the
outside air with respect to the refrigerant tube downstream portion
612.
[0129] In contrast, each cooling medium tube 71 includes a cooling
medium tube upstream portion 711 located on the upstream side of
the cooling medium side turning portion 71e, and a cooling medium
tube downstream portion 712 located on the downstream side of the
cooling medium side turning portion 71e. That is, the cooling
medium tube 71 of this embodiment is composed of the cooling medium
tube upstream portion 711, the cooling medium side turning portion
71e, and the cooling medium tube downstream portion 712. In the
cooling medium tube 71 of this embodiment, the cooling medium tube
upstream portion 711 is disposed on the upstream side in the flow
direction A of the outside air with respect to the cooling medium
tube downstream portion 712.
[0130] The refrigerant tubes 61 and the cooling medium tubes 71 in
this embodiment are disposed such that the refrigerant tube
upstream portions 611 and the cooling medium tube downstream
portions 712 are arranged in the lamination direction of the tubes
61 and 71, and such that the refrigerant tube downstream portions
612 and the cooling medium tube upstream portions 711 are arranged
in the lamination direction of the tubes 61 and 71.
[0131] With this arrangement, the refrigerant flowing through the
refrigerant tube 61 flows from the downstream side in the flow
direction of the outside air to the upstream side thereof, and the
coolant flowing through the cooling medium tube 71 flows from the
upstream side in the flow direction of the outside air to the
downstream side thereof. Thus, in the refrigerant tubes 61 and the
cooling medium tubes 71, the flow direction of refrigerant flowing
through the refrigerant tube 61 is opposite to that of the coolant
flowing through the cooling medium tube 71 with respect to the flow
direction A of the outside air.
[0132] Next, the refrigerant side header tank 62 and the cooling
medium side header tank 72 will be described later. The refrigerant
side header tank 62 has the same basic structure as that of the
cooling medium side header tank 72. The refrigerant side header
tank 62 includes a refrigerant side plate 63 to which both the
refrigerant tubes 61 and the cooling medium tubes 71 are fixed, and
a refrigerant side tank 64 fixed to the refrigerant side plate
63.
[0133] A part of the refrigerant side plate 63 corresponding to
each refrigerant tube 61 is provided with a communication hole
penetrating the plate. The refrigerant tube 61 passes through the
communication hole. Thus, the refrigerant flow path 61c of each
refrigerant tube 61 is in communication with the internal space of
the refrigerant side header tank 62. The width of the part of the
refrigerant tube 61 inserted into the communication hole in the
flow direction of the outside air is shorter than that of the
refrigerant flow path 61c.
[0134] Similarly, a part of the refrigerant side plate 63
corresponding to each cooling medium tube 71 is provided with a
communication hole penetrating the plate. The refrigerant tube 71
is inserted into the communication hole, so that the hole is
closed. The width of the part of the cooling medium tube 71
inserted into the communication hole in the flow direction of the
outside air is shorter than that of the cooling medium flow path
71c.
[0135] The refrigerant side plate 63 is fixed to the refrigerant
side tank 64 to thereby form a concave portion 63a for partitioning
a space formed between the plate 63 and tank 64. The concave
portion 63a is provided over the entire area of the refrigerant
side plate 63 in the longitudinal direction.
[0136] The refrigerant side tank 64 is fixed to the refrigerant
side plate 63 to thereby form a collection space 62a for collecting
the refrigerants therein, and a distribution space 62b for
distributing the refrigerant. Specifically, the refrigerant side
tank 64 is formed by pressing a flat metal plate into a double
mountain (W-like) shape as viewed in the longitudinal
direction.
[0137] A center portion 64a of the double mountain shape of the
refrigerant side tank 64 is coupled to the concave portion 63a of
the refrigerant side plate 63, which partitions the internal space
into the collection space 62a and the distribution space 62b. In
this embodiment, the collection space 62a is disposed on the
windward side in the flow direction A of the outside air, and the
distribution space 62b is disposed on the leeward side in the flow
direction A of the outside air.
[0138] As mentioned above, the refrigerant tube 61 passes through
the communication hole of the refrigerant side plate 63, so that
the refrigerant flow paths 61c (refrigerant tube downstream portion
612) disposed on the windward side in the flow direction A of the
outside air are brought into communication with the collection
space 62a, while the refrigerant flow paths 61c (refrigerant tube
upstream portion 611) disposed on the leeward side in the flow
direction A of the outside air are brought into communication with
the distribution space 62b.
[0139] As shown in FIG. 5, one end of the refrigerant side tank 64
in the longitudinal direction is connected to a refrigerant
introduction pipe 64b for introducing the refrigerant into the
distribution space 62b, and a refrigerant guiding pipe 64c for
guiding the refrigerant from the collection space 62a. The other
end of the refrigerant side tank 64 in the longitudinal direction
is closed by a closing member.
[0140] Also, as shown in FIG. 11, the cooling medium side header
tank 72 also includes a cooling medium side plate 73 and a cooling
medium side tank 74. The cooling medium tube 71 passes through a
communication hole provided at the part of the cooling medium plate
73 corresponding to the cooling medium tube 71. The refrigerant
tube 61 is inserted into another communication hole provided at the
part of the cooling medium plate 73 corresponding to the
refrigerant tube 61.
[0141] The cooling medium side tank 74 is fixed to the cooling
medium side plate 73, causing a concave portion 73a of the cooling
medium side plate 73 to be coupled to a center portion 74a in the
double mountain shape of the cooling medium side tank 74, which
partitions the internal space into a collection space 72a for
collecting the refrigerants therein, and a distribution space 72b
for distributing the refrigerant. In this embodiment, the
distribution space 72b is disposed on the windward side in the flow
direction A of the outside air, and the collection space 72a is
disposed on the leeward side in the flow direction A of the outside
air.
[0142] As mentioned above, the cooling medium tube 71 passes
through the communication hole of the cooling medium side plate 73,
so that the cooling medium flow paths 71c (cooling medium tube
upstream portion 711) disposed on the windward side in the flow
direction A of the outside air are brought into communication with
the distribution space 72b, while the cooling medium flow paths 71c
(cooling medium tube downstream portion 712) disposed on the
leeward side in the flow direction A of the outside air are brought
into communication with the collection space 72a.
[0143] As shown in FIG. 5, one end of the cooling medium side tank
74 in the longitudinal direction is connected to a cooling medium
introduction pipe 74b for introducing the cooling medium into the
distribution space 72b, and a cooling medium guiding pipe 74c for
guiding and deriving the cooling medium from the collection space
72a. The other end of the cooling medium side header tank 72 in the
longitudinal direction is closed by a closing member.
[0144] Thus, in the heat exchanger 16 of this embodiment, as shown
in the schematic perspective view of FIG. 10, the refrigerant
introduced into the distribution space 62b of the refrigerant side
header tank 62 via the refrigerant introduction pipe 64b flows into
each refrigerant flow path 61c (refrigerant tube upstream portion
611) of one of the refrigerant tubes 61 in two lines disposed on
the leeward side in the flow direction A of the outside air.
[0145] Then, the refrigerant flowing from each refrigerant flow
path 61c disposed on the leeward side (refrigerant tube upstream
portion 611) flows into the other refrigerant flow path 61 disposed
on the windward side (refrigerant tube downstream portion 612) via
the refrigerant side turning portion 61e. Further, the refrigerants
flowing from the refrigerant flow paths 61c (refrigerant tube
downstream portion 612) disposed on the windward side are collected
into the collection space 62a of the refrigerant side header tank
62, and then derived from the refrigerant guiding pipe 64c.
[0146] That is, in the heat exchanger 16 of this embodiment, the
refrigerant flows and turns around from the refrigerant flow path
61c on the leeward side of the refrigerant tube 61 (refrigerant
tube upstream portion 611) to the refrigerant side turning portion
61e, and the refrigerant flow path 61c on the windward side of the
refrigerant tube 61 (refrigerant tube downstream portion 612) in
that order.
[0147] Likewise, the coolant flows and turns around from the
cooling medium flow path 71c on the windward side of the cooling
medium tube 71 (cooling medium tube upstream portion 711) to the
cooling medium side turning portion 71e, and the cooling medium
flow path 71c on the leeward side of the cooling medium tube 71
(cooling medium tube downstream portion 712) in that order. Thus,
the refrigerants flowing through the adjacent refrigerant tubes 61
have the flow direction opposite to that of the coolants flowing
through the adjacent cooling medium tubes 71 in the longitudinal
direction of the tubes 61 and 71 and in the flow direction of the
outside air (which is referred to as an "opposite flow
structure").
[0148] Components of the above inner fins 65 and 72, the
refrigerant side header tank 62, the cooling medium side header
tank 72, and the outer fin 50 are formed of the same metal as that
of the plates 61a, 61b, 71a, and 71b forming the refrigerant tube
61 and the cooling medium tube 71.
[0149] Now, a manufacturing method of the heat exchanger 16 will be
described below. First, the refrigerant tubes 61, the cooling
medium tubes 71, the refrigerant side header tank 62, and the
cooling medium header tank 72 are temporarily fixed (which is
referred to as a "tube-tank temporary fixing step").
[0150] Specifically, in the refrigerant tube 61, the plates 61a and
61b are assembled such that the center of the one plate is aligned
with that of the other with the inner fin 65 fitted to the
refrigerant flow path 61c. A claw portion is formed in at least one
of the upstream side and the downstream side of the plate 61 in the
flow direction of the outside air (in this embodiment, the entire
area in the vertical direction). The claw portion is bent toward
the plate 61b.
[0151] In this embodiment, the plate 61a includes claw portions 61g
formed between the refrigerant flow paths 61c arranged in two
lines, and the claw portions are bent into through holes formed in
the plate 61b, so that the plate 61a is temporarily fixed to the
plate 61b. Likewise, in the cooling medium tube 71, the plates 71a
and 71b and the inner fin 75 are temporarily fixed together.
[0152] In the refrigerant side header tank 62, the refrigerant side
plate 63 and the refrigerant tank 64 are combined by bending the
claw portions formed at the outer peripheral ends of the
refrigerant side tank 64 over the refrigerant plate 63, so that the
plates 63 and 64 are temporarily fixed. Also, in the cooling medium
header tank 72, the cooling medium side plate 73 and the cooling
medium tank 74 are temporarily fixed.
[0153] The order of the temporary fixing of the refrigerant tube
61, the cooling medium tube 71, the refrigerant side header tank
62, and the cooling medium side header tank 72 is not limited to
the above.
[0154] Then, the refrigerant tube 61 and the cooling medium tube 71
are inserted into the communication holes provided in the
refrigerant side plate 63 of the refrigerant header tank 62 and in
the cooling medium side plate 73 of the cooling medium side header
tank 72, respectively. At this time, in this embodiment, the tubes
are inserted such that the distance between the edge of an opening
of the corresponding communication hole and each of the turning
portions 61e and 71e and the enlarging portions 61f and 71f is 3 mm
or less.
[0155] The outer fins 50 are inserted and temporarily fixed to the
outside air passages 16a formed in the refrigerant tubes 61 and the
cooling medium tubes 71, and then the respective
introduction/guiding pipes 64b, 64c, 74b, and 74c are temporarily
fixed (which is referred to as a "heat exchanger temporary fixing
step").
[0156] After fixing the heat exchanger 16 temporarily assembled
with a wire jig or the like, the entire heat exchanger 16 is put
and heated in a heating furnace. At this time, solder previously
cladded to the surface of each component is melted, and the heat
exchanger 16 is cooled until the solder is solidified again. As a
result, the respective components are integrally soldered (which is
referred to as a "heat exchanger bonding step"). The above method
can produce the heat exchanger including the outdoor heat
exchanging portion 60 and the radiator 70 which are integral with
each other.
[0157] As can be seen from the above description, the outdoor heat
exchanging portion 60 of this embodiment corresponds to a first
heat exchanging portion; the refrigerant tube 61 corresponds to a
first tube; the refrigerant side header tank 62 corresponds to a
first tank; and the refrigerant side turning portion 61e
corresponds to a first turning portion, for example.
[0158] The refrigerant tube upstream portion 611 of the cooling
medium tube 61 corresponds to a first tube upstream portion; and
the refrigerant tube downstream portion 612 corresponds to a first
tube downstream portion, for example.
[0159] In contrast, the radiator 70 corresponds to a second heat
exchanger; the cooling medium tube 71 corresponds to a second tube;
the cooling medium side header tank 72 corresponds to a second
tank; and the cooling medium side turning portion 71e corresponds
to a second turning portion, for example.
[0160] The cooling medium tube upstream portion 711 of the cooling
medium tube 71 corresponds to a second tube upstream portion; and
the cooling medium tube downstream portion 712 corresponds to a
second tube downstream portion, for example.
[0161] Now, an electric control unit of this embodiment will be
described below. The air conditioning controller is comprised of
the known microcomputer including a CPU, an ROM, and an RAM, and
peripheral circuits thereof. The control unit controls the
operation of each of various types of air conditioning controller
11, 15a, 15b, 17, 41, and 42 connected to its output by executing
various operations and processing based on air conditioning control
programs stored in the ROM.
[0162] A group of various sensors for control of air conditioning
is coupled to the input side of the air conditioning controller.
The sensors include an inside air sensor for detecting a
temperature of the vehicle interior, an outside air sensor for
detecting a temperature of the outside air, a solar radiation
sensor for detecting an amount of solar radiation in the vehicle
interior, and an evaporator temperature sensor for detecting a
temperature of blown air from the indoor evaporator 20 (evaporator
temperature). And, the sensors also include a discharged
refrigerant temperature sensor for detecting a temperature of the
refrigerant discharged from the compressor 11, an outlet
refrigerant temperature sensor 51 for detecting a refrigerant
temperature Te on the outlet side of the outdoor heat exchanging
portion 60, and a coolant temperature sensor 52 serving as coolant
temperature detection means for detecting a coolant temperature Tw
of the coolant flowing into the electric motor MG for
traveling.
[0163] In this embodiment, the coolant temperature sensor 52
detects the coolant temperature Tw of the coolant squeezed from the
coolant pump 41. Alternatively, the coolant temperature Tw of the
coolant sucked into the coolant pump 41 may be detected.
[0164] An operation panel (not shown) disposed near an instrument
board at the front of the vehicle compartment is connected to the
input side of the air conditioning controller. Operation signals
are input from various types of air conditioning operation switches
provided on the operation panel. Various air conditioning operation
switches provided on the panel include an operation switch for the
air conditioner for the vehicle, a vehicle-interior temperature
setting switch for setting the temperature of the vehicle interior,
and a selection switch for selecting an operation mode.
[0165] The air conditioning controller includes control means for
controlling the electric motor 11b for the compressor 11, and the
opening/closing valve 15a and the like which are integral with each
other, and is designed to control the operations of these
components. In the air conditioning controller of this embodiment,
the structure (hardware and software) for controlling the operation
of the compressor 11 serves as refrigerant discharge capacity
control means. The structure for controlling the operations of the
respective devices 15a and 15b forming the refrigerant flow path
switching means serves as refrigerant flow path control means. The
structure for controlling the operation of the three-way valve 42
forming the cooling medium circuit switching means for coolant
serves as cooling medium circuit control means.
[0166] The air conditioning controller of this embodiment includes
the structure (frost formation determination means) for determining
whether or not the frost is formed at the outdoor heat exchanger
60, based on a detection signal from the above sensor group for the
air conditioning control. Specifically, when the speed of a
travelling vehicle is equal to or less than a predetermined
reference value (in this embodiment, 20 km/h), and the refrigerant
temperature Te on the outlet side of the outdoor heat exchanger 60
is equal to or less than 0.degree. C., the frost formation
determination means of this embodiment determines that the frost
formation is caused at the outdoor heat exchanger 60.
[0167] Next, the operation of the vehicle air conditioner 1 with
the above arrangement in this embodiment will be described below.
The vehicle air conditioner 1 of this embodiment can execute a
heating operation for heating the vehicle interior, and a cooling
operation for cooling the vehicle interior. In the heating
operation, a defrosting operation and a waste heat recovering
operation can also be carried out. Now, each operation will be
explained in the following.
(a) Heating Operation
[0168] The heating operation is started when the heating operation
mode is selected by the selection switch with the operation switch
of the operation panel turned on (ON). Then, in the heating
operation, when the frost formation determination means determines
that the frost is formed at the outdoor heat exchanger 60, the
defrosting operation is performed. When the coolant temperature Tw
detected by the coolant temperature sensor 52 is equal to or more
than the predetermined reference temperature (in this embodiment,
60.degree. C.), the waste heat recovering operation is
performed.
[0169] In the normal heating operation, the air conditioning
controller closes the opening/closing valve 15a, and switches the
three-way valve 15b to the refrigerant flow path for coupling the
outlet side of the outdoor heat exchanging portion 60 to the inlet
side of the accumulator 18. Further, the controller actuates the
coolant pump 41 to squeeze the coolant in a predetermined flow
rate, and switches the three-way valve 42 of the coolant
circulation circuit 40 to the cooling medium circuit for allowing
the coolant to bypass the radiator 70.
[0170] In this way, the heat pump cycle 10 is switched to the
refrigerant flow path for allowing the refrigerant to flow as
illustrated by the solid arrow in FIG. 1. The coolant circulation
circuit 40 is also switched to the cooling medium circuit for
allowing the refrigerant to flow as illustrated by the dashed arrow
in FIG. 1.
[0171] The air conditioning controller with the above refrigerant
flow path and cooling medium circuit reads a detection signal from
the above sensor group for the air conditioning control and an
operation signal from the operation panel. Based on the detection
signal and the operation signal, a target outlet air temperature
TAO is calculated as the target temperature of the air to be blown
into the vehicle interior. Further, the operating states of various
air conditioning control components connected to the output side of
the air conditioning controller are determined based on the
calculated target outlet air temperature TAO and the detection
signal from the sensor group.
[0172] For example, the refrigerant discharge capacity of the
compressor 11, that is, a control signal output to the electric
motor of the compressor 11 is determined as follows. First, a
target evaporator outlet air temperature TEO of the indoor
evaporator 20 is determined based on the target outlet air
temperature TAO with reference to a control map previously stored
in the air conditioning controller.
[0173] Based on a deviation between the target evaporator outlet
air temperature TEO and the blown air temperature from the indoor
evaporator 20 detected by the evaporator temperature sensor, the
control signal to be output to the electrode motor of the
compressor 11 is determined such that the blown air temperature of
the air blown from the indoor evaporator 20 approaches the target
evaporator outlet air temperature TEO by use of a feedback control
method.
[0174] The control signal to be output to the servo motor of the
air mix door 34 is determined based on the target outlet air
temperature TAO, the blown air temperature of the indoor evaporator
20, and the temperature of the refrigerant discharged from the
compressor 11 detected by the discharge refrigerant temperature
sensor such that the temperature of air blown into the vehicle
interior becomes a desired temperature set by the passenger using
the vehicle interior temperature setting switch.
[0175] During the normal heating operation, the defrosting
operation, and the waste heat recovering operation, the opening
degree of the air mix door 34 may be controlled such that the whole
volume of air in the vehicle interior blown from the blower 32
passes through the indoor condenser 12.
[0176] Then, the control signals determined as described above are
output to various air conditioning control components. Thereafter,
until the stopping of the vehicle air conditioner is requested by
the operation panel, a control routine is repeated at every
predetermined control cycle. The control routine includes a series
of processes: reading of the detection signal and the operation
signal, calculation of the target outlet air temperature TAO,
determination of the operating states of various air conditioning
control components, and output of the control voltage and the
control signal in that order. Such repetition of the control
routine is basically performed in other operation modes in the same
way.
[0177] In the heat pump cycle 10 during the normal heating
operation, the high-pressure refrigerant discharged from the
compressor 11 flows into the indoor condenser 12. The refrigerant
flowing into the indoor condenser 12 exchanges heat with the
vehicle interior air blown by the blower 32 through the indoor
evaporator 20 to dissipate the heat therefrom, so that the air in
the vehicle compartment is heated.
[0178] The high-pressure refrigerant flowing from the indoor
condenser 12 flows into the fixed throttle 13 for heating to be
decompressed and expanded by the throttle 13 because the
opening/closing valve 15a is closed. The low-pressure refrigerant
decompressed and expanded by the fixed throttle 13 for heating
flows into an outdoor heat exchanging portion 60. The low-pressure
refrigerant flowing into the outdoor heat exchanging portion 60
absorbs heat from the outside air blown by the blower fan 17, and
is evaporated.
[0179] At this time, the coolant circulation circuit 40 is switched
to the cooling medium circuit for allowing the coolant to bypass
the radiator 70, which prevents the coolant from dissipating heat
to the refrigerant flowing through the outdoor heat exchanging
portion 60, and also prevents the coolant from absorbing heat from
the refrigerant flowing through the outdoor heat exchanging portion
60. That is, the coolant never has a thermal influence on the
refrigerant flowing through the outdoor heat exchanging portion
60.
[0180] Since the three-way valve 15b is switched to the refrigerant
flow path connecting the outlet side of the outdoor heat exchanging
portion 60 to the inlet side of the accumulator 18, the refrigerant
flowing from the outdoor heat exchanging portion 60 flows into the
accumulator 18 and is separated into liquid and gas phases. The
gas-phase refrigerant separated by the accumulator 18 is sucked by
the compressor 11 and compressed again.
[0181] As mentioned above, in the normal heating operation, the air
in the vehicle interior is heated by the indoor condenser 12 with
the heat contained in the refrigerant discharged from the
compressor 11, which can perform the heating operation of the
vehicle interior.
(b) Defrosting Operation
[0182] Next, the defrosting operation will be described below. In
the refrigeration cycle device for evaporating the refrigerant by
exchanging heat between the refrigerant and outside air in the
outdoor heat exchanging portion 60, like the heat pump cycle 10 of
this embodiment, when a refrigerant evaporation temperature of the
outdoor heat exchanging portion 60 becomes equal to or less than a
frost formation temperature (specifically, 0.degree. C.), the frost
might be formed at the outdoor heat exchanging portion 60.
[0183] Such formation of the frost closes the outside air passage
16a of the heat exchanger 16 with the frost, which drastically
reduces the heat exchange capacity of the outdoor heat exchanging
portion 60. In the heat pump cycle 10 of this embodiment, when the
frost formation is determined to be caused at the outdoor heat
exchanging portion 60 by the frost formation determination means in
the heating operation, the defrosting operation is started.
[0184] In the defrosting operation, the air conditioning controller
stops the operation of the compressor 11, and also stops the
operation of the blower fan 17. Thus, during the defrosting
operation, the flow rate of refrigerant flowing into the outdoor
heat exchanging portion 60 is decreased to thereby decrease the
volume of outside air flowing into the outside air passage 16a, as
compared to the normal heating operation.
[0185] The air conditioning controller switches the three-way valve
42 of the coolant circulation circuit 40 to the cooling medium
circuit for allowing the coolant to flow into the radiator 70 as
indicated by the dashed arrow in FIG. 2. Thus, the coolant
circulation circuit 40 is switched to the cooling medium circuit
for flowing the refrigerant as indicated by the dashed arrow in
FIG. 2 without circulation of the refrigerant through the heat pump
cycle 10.
[0186] Thus, the heat contained in the coolant flowing through the
cooling medium tubes 71 of the radiator 70 is transferred to the
outdoor heat exchanging portion 60 via the outer fins 50, which
performs the defrosting operation of the outdoor heat exchanging
portion 60. That is, the flow rates of the refrigerant and outside
air flowing through the heat exchanger 16 are changed
(specifically, reduced) to achieve the defrosting operation
effectively using the waste heat of the electric motor MG for
traveling.
(c) Waste Heat Recovering Operation
[0187] Next, the waste heat recovering operation will be described
below. Preferably, in order to suppress overheat of the electric
motor MG for traveling, the temperature of the coolant is
maintained at a predetermined upper limit temperature or less.
Further, in order to reduce the friction loss due to an increase in
viscosity of oil for lubrication sealed into the electric motor MG
for traveling, preferably, the temperature of the coolant is
maintained at a predetermined lower limit temperature or more.
[0188] In the heat pump cycle 10 of this embodiment, when the
coolant temperature Tw is equal to or more than the predetermined
reference temperature (60.degree. C. in this embodiment) during the
heating operation, the waste heat recovering operation is
performed. In the defrosting operation, the three-way valve 15b of
the heat pump cycle 10 is performed in the same way as in the
normal heating operation, but the three-way valve 42 of the coolant
circulation circuit 40 is switched to the cooling medium circuit
for flowing the coolant into the radiator 70 as indicated by the
dashed arrow in FIG. 3 in the same way as in the defrosting
operation.
[0189] Thus, as illustrated by the solid arrow in FIG. 3, the
high-pressure and high-temperature refrigerant discharged from the
compressor 11 heats the air in the vehicle interior at the indoor
condenser 12, and is then decompressed and expanded by the fixed
throttle 13 for heating to flow into the outdoor heat exchanging
portion 60 in the same way as in the normal heating operation.
[0190] Since the three-way valve 42 performs switching to the
cooling medium circuit for flowing the coolant into the radiator
70, the low-pressure refrigerant flowing into the outdoor heat
exchanging portion 60 absorbs both the heat contained in the
outside air blown by the blower fan 17 and the heat contained in
the coolant and transmitted thereto via the outer fins 50, thereby
to be evaporated. Other operations are the same as those in the
normal heating operation.
[0191] As described above, in the waste heat recovering operation,
the air in the vehicle interior is heated at the indoor condenser
12 with the heat of the refrigerant discharged from the compressor
11, which can perform heating of the vehicle interior. At this
time, the refrigerant absorbs not only the heat contained in the
outside air, but also the heat contained in the coolant and
transmitted thereto via the outer fins 50, which can achieve the
heating of the vehicle interior effectively using the waste heat of
the electric motor MG for traveling.
(d) Cooling Operation
[0192] The cooling operation is started when the cooling operation
mode is selected by the selection switch with the operation switch
of the operation panel turned on (ON). In the cooling operation,
the air conditioning controller opens the opening/closing valve
15a, and switches the three-way valve 15b to the refrigerant flow
path for connecting the outlet side of the outdoor heat exchanging
portion 60 to the inlet side of the fixed throttle 19 for cooling.
Thus, the heat pump cycle 10 is switched to the refrigerant flow
path for flowing the refrigerant as indicated by the solid arrow in
FIG. 4.
[0193] At this time, when the coolant temperature Tw is equal to or
more than the reference temperature, the three-way valve 42 of the
coolant circulation circuit 40 is switched to the cooling medium
circuit for flowing the coolant into the radiator 70. In contrast,
when the coolant temperature Tw is less than the predetermined
reference temperature, the three-way valve 42 is switched to the
cooling medium circuit for allowing the coolant to bypass the
radiator 70. The flow of the coolant obtained when the coolant
temperature Tw is equal to or more than the reference temperature
is indicated by the dashed arrow in FIG. 4.
[0194] In the heat pump cycle 10 during the cooling operation, the
high-pressure refrigerant discharged from the compressor 11 flows
into the indoor condenser 12, and exchanges heat with the air in
the vehicle interior blown by the blower 32 and having passed
through the indoor evaporator 20 to dissipate heat therefrom. The
high-pressure refrigerant flowing from the indoor condenser 12
flows into the outdoor heat exchanging portion 60 via the bypass
passage 14 for the fixed throttle because the opening/closing valve
15a is opened. The low-pressure refrigerant flowing into the
outdoor heat exchanging portion 60 further radiates heat toward the
outside air blown by the blower fan 17.
[0195] Since the three-way valve 15b is switched to the refrigerant
flow path for connecting the outlet side of the outdoor heat
exchanging portion 60 to the inlet side of the fixed throttle 19
for cooling, the refrigerant flowing from the outdoor heat
exchanging portion 60 is decompressed and expanded by the fixed
throttle 19 for cooling. The refrigerant flowing from the fixed
throttle 19 for cooling flows into the indoor evaporator 20, and
absorbs heat from the air in the vehicle interior blown by the
blower 32 to be evaporated. In this way, the air in the vehicle
interior can be cooled.
[0196] The refrigerant flowing from the indoor evaporator 20 flows
into the accumulator 18, and is then separated into liquid and gas
phases by the accumulator 18. The gas-phase refrigerant separated
by the accumulator 18 is sucked into and compressed by the
compressor 11 again. As mentioned above, during the cooling
operation, the low-pressure refrigerant absorbs heat from the air
in the vehicle interior and evaporates itself at the indoor
evaporator 20 to thereby cool the air in the vehicle compartment,
which can perform cooling of the vehicle interior.
[0197] As described above, the air conditioner 1 for the vehicle in
this embodiment can perform switching among the refrigerant flow
paths of the heat pump cycle 10, and among the cooling medium
circuits of the coolant circulation circuit 40 to thereby carry out
various operations. Further, in this embodiment, the above specific
heat exchanger 16 can be used to perform appropriate heat exchange
among three kinds of fluids, namely, refrigerant, coolant, and
outside air in each operation.
[0198] More specifically, the heat exchanger 16 of this embodiment
includes outer fins 50 each disposed in the outside air passage 16a
formed between the refrigerant tube 61 of the outdoor heat
exchanging portion 60 and the cooling medium tube 71 of the
radiator 70. Such outer fins 50 enable heat transfer between the
refrigerant tubes 61 and the cooling medium tubes 71.
[0199] Thus, during the defrosting operation, the heat contained in
the coolant can be transferred to the outdoor heat exchanging
portion 60 via the outer fins 50, which can effectively use the
waste heat of the electric motor MG for traveling to defrost the
outdoor heat exchanging portion 60.
[0200] Further, in this embodiment, during the defrosting
operation, the operation of the compressor 11 is stopped to reduce
the flow rate of refrigerant flowing into the outdoor heat
exchanging portion 60, which can prevent the heat transferred to
the outdoor heat exchanging portion 60 from absorbing in the
refrigerant flowing through the refrigerant tubes 61 via the outer
fins 50 and the refrigerant tubes 61. That is, unnecessary heat
exchange between the coolant and the refrigerant can be
suppressed.
[0201] During the defrosting operation, the operation of the blower
fan 17 is stopped to decrease the volume of outside air flowing
into the outside air passages 16a, which can prevent the heat
transmitted to the outdoor heat exchanging portion 60 via the outer
fins 50 from being absorbed in the outside air flowing through the
outside air passages 16a. That is, the unnecessary heat exchange
between the coolant and outside air can be suppressed.
[0202] During the waste heat recovering operation, the heat
exchanger exchanges heat between the coolant and the refrigerant
via the refrigerant tubes 61, the cooling medium tubes 71, and the
outer fins 50, so that the waste heat of the electric motor MG for
traveling can be absorbed in the refrigerant. And the heat
exchanger also exchanges heat between the coolant and the outside
air via the cooling medium tubes 71 and the outer fins 50, so that
the unnecessary waste heat of the electric motor MG for traveling
can be dissipated to the outside air.
[0203] During the normal heat operation, the heat exchanger
exchanges heat between the refrigerant and the outside air via the
refrigerant tubes 61 and the outer fins 50, so that the heat of the
outside air can be absorbed in the refrigerant. And during the
normal heat operation, the three-way valve 42 of the coolant
circulation circuit 40 is switched to the cooling medium circuit
for allowing the coolant to bypass the radiator 70, which can
suppress the unnecessary heat exchange between the coolant and
outside air to store the waste heat of the electric motor MG for
traveling in the coolant, thus promoting the warming of the
electric motor MG for traveling.
[0204] In the heat exchanger 16 of this embodiment, the refrigerant
tubes 61 and the cooling medium tubes 71 are disposed between the
refrigerant side header tank 62 and the cooling medium side header
tank 72, so that each outside air passage 16a is formed of a space
between the refrigerant tube 61 and the cooling medium tube 71. The
refrigerant side header tank 62 and the cooling medium side header
tank 72 are not arranged in the flow direction of the outside air.
Thus, the entire heat exchanger 16 can be prevented from increasing
in size in the flow direction of the outside air.
[0205] Additionally, the refrigerant side turning portion 61e of
the refrigerant tube 61 is positioned closer to the cooling medium
side header tank 72 than the refrigerant side header tank 62. And
the cooling medium side turning portion 71e of the cooling medium
tube 71 is positioned closer to the refrigerant header tank 62 than
the cooling medium side header tank 72. The structure with the
refrigerant side header tank 62 connected to the refrigerant tubes
61 can have the same shape as that of the structure with the
cooling medium side header tank 72 connected to the cooling medium
tube 71.
[0206] In this embodiment, the refrigerant side plate 63 of the
refrigerant side header tank 62 and the cooling medium side plate
73 of the cooling medium side header tank 72 are provided with
communication holes in communication with the refrigerant flow path
61c and the cooling medium flow path 71c, respectively, and other
closed communication holes. The structure for connecting the
refrigerant tubes 61 to the refrigerant side header tank 62 can
have the same shape as that for connecting the cooling medium tubes
71 to the cooling medium side header tank 72, which can improve the
productivity of the heat exchanger.
[0207] As a result, the heat exchanger 16 of this embodiment can
improve the productivity of the heat exchanger that can exchange
heat among three kinds of fluids without increase in size.
[0208] In the heat exchanger 16 of this embodiment, the refrigerant
tube 61 and the cooling medium tube 71 are fixed to both the
refrigerant side header tank 62 and the cooling medium side header
tank 72, which can increase the mechanical strength of the entire
heat exchanger 16. Further, in a temporary process of the outer fin
50 to be disposed in the outside air passage 16a, the outer fin 50
can be easily fixed temporarily, and then can be strongly fixed
after the temporary bonding.
[0209] The refrigerant passage area of an intermediate part of each
of the refrigerant side turning portion 61e and the cooling medium
side turning portion 71e is larger than a fluid passage area of
each of a fluid inflow portion and a fluid outflow portion of the
corresponding turning portion. When the refrigerant passes through
the refrigerant side turning portion 61e, or when the coolant
passes through the cooling medium side turning portion 71e, the
loss in pressure can be reduced.
[0210] The ends of the inner fins 65 and 75 disposed inside the
refrigerant tube 61 and the cooling medium tube 71 protrude into
the internal spaces of the enlarging portions 61f and 71f of the
respective turning portions 61e and 71e. Thus, the parts of the
inner fins 65 and 75 where the cladded solder is apt to be peeled
off, such as the ends of the inner fins 65 and 75, do not serve as
a surface of interest to be soldered, which tends to suppress the
bonding defect between each of the inner fins 65 and 75 and the
inner peripheral surface of each of the refrigerant tube 61 and the
cooling medium tube 71.
[0211] Like this embodiment, in the heat exchanger 16 that can
exchange heat among three kinds of fluids, the temperature of
refrigerant introduced into the outdoor heat exchanging portion 60
sometimes differs from that of coolant introduced into the radiator
70, depending on the operation condition. In this case, the amount
of thermal strain (heat expansion amount) generated in the
refrigerant tube 61 differs from that generated in the cooling
medium tube 71, which might lead to a breakdown of the heat
exchanger 16.
[0212] In contrast, the heat exchanger 16 of this embodiment
includes the outer fins 50 disposed between the refrigerant tubes
61 and the cooling medium tubes 71, which are alternately laminated
or stacked at predetermined intervals. Each outer fin 50 promotes
the heat exchange among the outside air, the refrigerant, and the
coolant to thereby relieve the difference in thermal strain between
the tubes 61 and 71. Thus, the heat exchanger 16 of this embodiment
can suppress the breakdown of the refrigerant tube 61 and the
cooling medium tube 71 due to the difference in thermal strain
(heat expansion amount) generated between the refrigerant tubes 61
and the cooling medium tubes 71.
[0213] In the heat exchanger 16 of this embodiment, the cooling
medium tube upstream portion 711 of the cooling medium tube 71 is
located on the upstream side in the flow direction A of the outside
air with respect to the cooling medium tube downstream portion 712.
Thus, in an operating state where the temperature of the cooling
medium flowing into the cooling medium tube 71 is higher than the
temperature of each of the refrigerant and outside air, the
difference in temperature between the coolant and the outside air
can be ensured on the upstream side of the coolant flow of the
cooling medium tube 71 to thereby increase the amount of heat
dissipation. As a result, the difference in temperature between the
coolant and the refrigerant can be reduced to relieve the
difference in thermal strain between the refrigerant tube 61 and
the cooling medium tube 71. In this example, the coolant
corresponds to the "high-temperature side fluid"; the cooling
medium tube 71 to the "high-temperature side tube"; the cooling
medium tube upstream portion 711 of the cooling medium tube 71 to
the "high-temperature side tube upstream portion"; and the cooling
medium tube downstream portion 712 of the cooling medium tube 71 to
the "high-temperature side tube downstream portion". The
refrigerant corresponds to the "low-temperature side fluid"; the
refrigerant tube 61 to the "low-temperature side tube"; the
refrigerant tube upstream portion 611 of the refrigerant tube 61 to
the "low-temperature side tube upstream portion"; and the
refrigerant tube downstream portion 612 of the refrigerant tube 61
to the "low-temperature side tube downstream portion".
Second Embodiment
[0214] In this embodiment, some changes are made to the structure
of the heat exchanger 16 of the first embodiment. The detailed
structure of a heat exchanger 16 of this embodiment will be
described below using FIGS. 12 to 14.
[0215] FIG. 12 shows a perspective view of the contour of the heat
exchanger 16 in the first embodiment. FIG. 13 shows a schematic
perspective view for explaining the flows of refrigerant and
coolant in the heat exchanger 16. FIG. 14 shows a schematic
partially exploded perspective view of the heat exchanger 16. FIGS.
12, 13, and 14 correspond to FIGS. 5, 10, and 11 of the first
embodiment, respectively. In FIGS. 12 to 14, the same or equivalent
parts as those in the first embodiment are indicated by the same
reference characters. The same goes for all the following
drawings.
[0216] As shown in FIGS. 12 and 14, each of the refrigerant tube 61
and the cooling medium tube 71 of this embodiment is formed by
bending a flat tube with a flat section in the direction
perpendicular to the longitudinal direction. More specifically, the
refrigerant tube 61 is bent such that the flat surfaces thereof are
opposed to each other, and the cooling medium tube 71 is also bent
such that the flat surfaces thereof are opposed to each other.
[0217] Thus, the refrigerant side turning portion 61e of the
refrigerant tube 61 and the cooling medium side turning portion 71e
of the cooling medium tube 71 in this embodiment are formed of the
bent portions of the tubes 61 and 71, respectively. The outside air
passages 16a in this embodiment are formed not only between the
flat surface of the refrigerant tube 61 and the flat surface of the
cooling medium tube 71 opposed thereto, but also between the flat
surfaces of the opposed refrigerant tubes 61, and between the flat
surfaces of the opposed cooling medium tubes 71.
[0218] The outside air passages 16a are provided with the outer
fins 50 which are the same as in the first embodiment. FIG. 14
omits the illustration of the outer fins 50 for easy understanding,
like FIG. 11.
[0219] As shown in FIG. 14, the refrigerant tubes 61 are arranged
in two lines along the flow direction A of the outside air. An
opening end of one refrigerant tube 61 disposed on the leeward side
is in communication with the distribution space 62b of the
refrigerant side header tank 62, while an opening end of the other
tube 61 disposed on the windward side is in communication with the
collection space 62a of the refrigerant side header tank 62.
[0220] A partition member (not shown) is disposed inside the
refrigerant side header tank 62. The partition member causes the
other opening end of the one refrigerant tube 61 disposed on the
leeward side to be brought into communication with the other
opening end of the other tube 61 disposed on the windward side
without communicating with the collection space 62a and the
distribution space 62b inside the refrigerant side header tank
62.
[0221] As shown in FIG. 14, the cooling medium tubes 71 are
arranged in two lines along the flow direction A of the outside
air. An opening end of one cooling medium tube 71 disposed on the
windward side is in communication with the distribution space 72b
of the cooling medium side header tank 72, while an opening end of
the other tube 71 disposed on the leeward is in communication with
the collection space 72a of the cooling medium side header tank
72.
[0222] A partition member (not shown) is also disposed inside the
cooling medium side header tank 72. The partition member causes the
other opening end of the one cooling medium tube 71 disposed on the
windward side to be brought into communication with the other
opening end of the other tube 71 disposed on the leeward side
without communicating with the collection space 72a and the
distribution space 72b inside the cooling medium side header tank
72.
[0223] Thus, as shown in FIG. 13, in the heat exchanger 16 of this
embodiment, the refrigerant introduced into the distribution space
62b of the refrigerant side header tank 62 flows into the
refrigerant tube 61 disposed on the leeward side to pass through
the refrigerant side turning portion 61e of the refrigerant tube 61
disposed on the leeward side, and then returns to the refrigerant
side header tank 62. Then, the refrigerant flows into the
refrigerant tube 61 disposed on the windward side to pass through
the refrigerant side turning portion 61e of the refrigerant side
tube 61 disposed on the windward side, and is derived from the
collection space 62a of the refrigerant side header tank 62.
[0224] In contrast, the refrigerant introduced into the
distribution space 72b of the cooling medium side header tank 72
flows into the cooling medium tube 71 disposed on the windward side
to pass through the cooling medium side turning portion 71e of the
cooling medium tube 71 disposed on the windward side, and then
returns to the cooling medium side header tank 72. Then, the
refrigerant flows into the cooling medium tube 71 disposed on the
leeward side to pass through the cooling medium side turning
portion 71e of the cooling medium side tube 71 disposed on the
leeward side, and is derived from the collection space 72a of the
cooling medium side header tank 72.
[0225] The structures and operations of other components of the
heat pump cycle 10 including the heat exchanger 16 are the same as
those of the first embodiment. Thus, like the first embodiment, the
heat exchanger 16 of this embodiment can also perform the
appropriate heat exchange among three kinds of fluids, refrigerant,
coolant, and outside air in each operation of the heat pump cycle
10. This embodiment can also improve the productivity of the heat
exchanger that can exchange heat among the three kinds of fluids
without increase in size.
[0226] Further, the heat exchanger 16 of this embodiment uses as
the refrigerant tube 61 and the cooling medium tube 71, the flat
tube that can be formed at low cost by an extrusion process or
drawing process. Therefore, this embodiment can further improve the
productivity.
Third Embodiment
[0227] The second embodiment uses the flat tube bent with the flat
surface parts opposed to each other, as the refrigerant tube 61 and
the cooling medium tube 71, by way of example. In this embodiment,
as shown in FIG. 15, each tube is bent such that a flat surface on
the upstream side of each of the turning portions 61e and 71e and a
flat surface on the downstream side thereof are arranged in two
lines on the same plane in the flow direction A of the outside
air.
[0228] In FIG. 15, (a) is a front view of the refrigerant tube 61
of this embodiment (cooling medium tube 71), and (b) is a side view
of the tube for refrigerant. FIGS. 15(a) and 15(b) correspond to
FIGS. 6(a) and 6(b) of the first embodiment. FIGS. 15(a) and 15(b)
shows the refrigerant tube 61, while components of the cooling
medium tube 71 corresponding to the components of the refrigerant
tube 61 are indicated by respective reference numerals within
parentheses.
[0229] The structures and operations of other components of the
heat pump cycle 10 including the heat exchanger 16 are the same as
those of the first embodiment. Thus, like the first embodiment, the
heat exchanger 16 of this embodiment can also perform the
appropriate heat exchange among three kinds of fluids, refrigerant,
coolant, and outside air in each operation of the heat pump cycle
10. This embodiment can also improve the productivity of the heat
exchanger that can exchange heat among the three kinds of fluids
without increase in size.
[0230] Like the second embodiment, this embodiment can also
manufacture the refrigerant tube 61 and the cooling medium tube 71
at low cost, and thus can further improve the productivity.
Fourth Embodiment
[0231] In this embodiment, as shown in the entire configuration
diagram of FIG. 16, some changes are made to the structure of the
heat pump cycle 10 of the first embodiment. FIG. 16 shows the
entire configuration diagram of refrigerant flow paths in the waste
heat recovering operation in this embodiment. In the figure, the
flow of refrigerant in the heat pump cycle 10 is indicated by a
solid line, and the flow of coolant in the coolant circulation
circuit 40 is indicated by a dashed arrow.
[0232] Specifically, in this embodiment, the indoor condenser 12 of
the first embodiment is removed, and the compound heat exchanger 16
of the first embodiment is disposed in the casing 31 of the indoor
air conditioning unit 30. The outdoor heat exchanging portion 60 of
the first embodiment in the compound heat exchanger 16 serves as
the indoor condenser 12. In the following, a portion of the heat
exchanger 16 serving as the indoor condenser 12 is referred to as
an "indoor condenser".
[0233] In contrast, the outdoor heat exchanging portion 60 is
composed of a single heat exchanger for exchanging heat between the
refrigerant flowing therethrough and the outside air blown by the
blower fan 17. The structures of other components in this
embodiment are the same as those of the first embodiment. In this
embodiment, the defrosting operation is not performed, but other
operations are performed in the same way as the first
embodiment.
[0234] Thus, during the waste heat recovering operation in this
embodiment, the air in the vehicle interior is heated by exchanging
heat with the refrigerant discharged from the compressor 11 in the
indoor evaporator of the heat exchanger 16. Further, the air in the
vehicle interior heated by the indoor condenser can be heated by
exchanging heat with coolant in the radiator 70 of the heat
exchanger 16.
[0235] The structure of the heat pump cycle 10 of this embodiment
can exchange heat between the air in the vehicle interior and the
coolant. Even when the operation of the heat pump cycle 10
(specifically, compressor 11) is stopped, the heating of the
vehicle interior can be achieved. Even when the temperature of the
refrigerant discharged from the compressor 11 is low and the
heating capacity of the heat pump cycle 10 is low, the heating of
the vehicle interior can be achieved.
[0236] Obviously, the heat exchanger 16 disclosed in the second and
third embodiments may be applied to the heat pump cycle 10 of this
embodiment.
Fifth Embodiment
[0237] In this embodiment, some changes are made to the structure
of the heat exchanger 16 of the first embodiment. The detailed
structure of a heat exchanger 16 of this embodiment will be
described below using FIGS. 17 and 18.
[0238] FIG. 18 shows a perspective view of the contour of the heat
exchanger 16 in this embodiment. FIG. 18 is a schematic perspective
view for explaining the flows of refrigerant and coolant in the
heat exchanger 16. FIGS. 17 and 18 correspond to FIGS. 5 and 10 of
the first embodiment. For convenience of the description, FIG. 17
omits the illustration of the tubes 61 and 71 and the outer fins 50
of the heat exchanger 16.
[0239] The outdoor heat exchanging portion 60 of the heat exchanger
16 in this embodiment includes a refrigerant side header tank 62
composed of tanks 621 and 622 arranged in two lines along the flow
direction A of the outside air. The first refrigerant tank 621
disposed on the upstream side in the flow direction of the outside
air of the tanks 621 and 622 in two lines is provided with a
partition member 621c disposed in the center in the longitudinal
direction for partitioning the internal space into two spaces 621a
and 621b.
[0240] The first refrigerant tank 621 is connected to tubes
disposed on the windward side in the flow direction A of the
outside air among a plurality of refrigerant tube upstream portions
611 and refrigerant tube downstream portions 612. The tank 621
serves as a collection and distribution tank for collecting and/or
distributing the refrigerants flowing through the tubes.
[0241] One end of the first refrigerant tank 621 in the
longitudinal direction is connected to the refrigerant introduction
pipe 64b for introducing the refrigerant, and the other end of the
refrigerant side tank 64 in the longitudinal direction is connected
to the refrigerant guiding pipe 64c for deriving and guiding the
refrigerant. The refrigerant introduction pipe 64b is in
communication with the distribution space 621a of the two spaces
621a and 621b formed in the first refrigerant tank 621. The
refrigerant guiding pipe 64c is in communication with the
collection space 621b of the two spaces 621a and 621b formed in the
first refrigerant tank 621.
[0242] Among the tanks 621 and 622 arranged in two lines and
included in the refrigerant side header tank 62, the second
refrigerant tank 622 disposed on the downstream side in the flow
direction A of the outside air is connected to the tubes disposed
on the leeward side in the flow direction A of the outside air
among the plurality of refrigerant tube upstream portions 611 and
the refrigerant tube downstream portions 612. The second
refrigerant tank 622 serves as a collection and distribution tank
for collecting and/or distributing the refrigerants flowing through
the tubes. Both ends of the second refrigerant tank 622 in the
longitudinal direction are closed by closing members.
[0243] A group of the refrigerant tubes 61 for flowing therethrough
the refrigerant introduced into the outdoor heat exchanging portion
60 via the refrigerant introduction pipe 64b forms an upstream side
refrigerant tube group 60a. Another group of the refrigerant tubes
61 for flowing therethrough the refrigerant from the upstream side
refrigerant tube group 60a to derive the refrigerant from the
refrigerant guiding pipe 64c forms a downstream side refrigerant
tube group 60b.
[0244] In the refrigerant tubes 61 forming the upstream side
refrigerant tube group 60a, the refrigerant tube upstream portion
611 is disposed on the upstream side in the flow direction A of the
outside air with respect to the refrigerant tube downstream portion
612. In the refrigerant tubes 61 forming the downstream side
refrigerant tube group 60b, the refrigerant tube upstream portion
611 is disposed on the downstream side in the flow direction A of
the outside air with respect to the refrigerant tube downstream
portion 612.
[0245] In the outdoor heat exchanging portion 60 of this
embodiment, as indicated by a solid arrow in the schematic
perspective view of FIG. 18, the refrigerant introduced into the
distribution space 621a of the first refrigerant tank 621 of the
header tank 62 via the refrigerant introduction pipe 64b flows from
the refrigerant tube upstream portion 611 on the windward side in
the outside air flow direction A in the upstream side refrigerant
tube group 60a to the refrigerant side turning portion 61e. The
refrigerant then flows and turns around to the refrigerant tube
downstream portion 612 on the leeward side in the outside air flow
direction A in the upstream side refrigerant tube group 60a. The
refrigerant flowing from the refrigerant tube downstream portion
612 into the second refrigerant tank 622 flows and turns around
from the refrigerant tube upstream portion 611 on the leeward side
in the flow direction A of the outside air in the downstream side
refrigerant tube group 60b to the refrigerant side turning portion
61e, and the refrigerant tube downstream portion 612 on the
windword side in the outside air flow direction A in the downstream
side refrigerant tube group 60b in that order.
[0246] Turning back to FIG. 17, the radiator 70 of the heat
exchanger 16 of this embodiment includes the cooling medium side
header tank 72 composed of tanks 721 and 722 arranged in two lines
along the flow direction A of the outside air. The first cooling
medium tank 721 disposed on the upstream side in the flow direction
of the outside air of the tanks 721 and 722 in two lines is
provided with a partition member 721c disposed in the center in the
longitudinal direction for partitioning the internal space into two
spaces.
[0247] The first cooling medium tank 721 is connected to tubes
disposed on the windward side in the flow direction A of the
outside air among a plurality of the cooling medium tube upstream
portions 711 and the cooling medium tube downstream portions 712.
The tank 721 serves as a collection and distribution tank for
collecting and/or distributing the refrigerants flowing through the
tubes.
[0248] One end of the first cooling medium tank 721 in the
longitudinal direction is connected to the cooling medium
introduction pipe 74b for introducing the cooling medium, and the
other end of the cooling medium side tank 74 in the longitudinal
direction is connected to the cooling medium guiding pipe 74c for
deriving and guiding the cooling medium. The cooling medium
introduction pipe 74b is in communication with the distribution
space 721a of the two spaces 721a and 721b formed in the first
cooling medium tank 721. The cooling medium guiding pipe 74c is in
communication with the collection space 721b of the two spaces 721a
and 721b formed in the first cooling medium tank 721.
[0249] Among the tanks 721 and 722 arranged in two lines and
included in the cooling medium side header tank 72, the second
cooling medium tank 722 disposed on the downstream side in the flow
direction A of the outside air is connected to the tubes disposed
on the leeward side in the flow direction A of the outside air
among the cooling medium tube upstream portions 711 and the cooling
medium tube downstream portions 712. The second cooling medium tank
serves as a collection and distribution tank for collecting and/or
distributing the cooling medium flowing through the tubes. Both
ends of the second cooling medium tank 722 in the longitudinal
direction are closed by closing members.
[0250] A group of the cooling medium tubes 71 for flowing
therethrough the coolant introduced into the radiator 70 via the
cooling medium introduction pipe 74b forms an upstream side cooling
medium tube group 70a. Another group of the cooling medium tubes 71
for flowing therethrough the coolant from the upstream side cooling
medium tube group 70a to derive the coolant from the cooling medium
guiding pipe 74c forms a downstream side cooling medium tube group
70b.
[0251] In the cooling medium tubes 71 forming the upstream side
cooling medium tube group 70a, the cooling medium tube upstream
portion 711 is placed on the upstream side in the flow direction A
of the outside air with respect to the cooling medium tube
downstream portion 712. In the cooling medium tubes 71 forming the
downstream side cooling medium tube group 70b, the cooling medium
tube upstream portion 711 is placed on the downstream side in the
flow direction A of the outside air with respect to the cooling
medium tube downstream portion 712.
[0252] In the radiator 70 of this embodiment, as indicated by a
chain arrow in the schematic perspective view of FIG. 18, the
refrigerant introduced into the distribution space 721a of the
first cooling medium tank 721 of the cooling medium side header
tank 72 via the refrigerant 64b flows from the cooling medium tube
upstream portion 711 on the windward side in the flow direction A
of the outside air in the upstream side cooling medium tube group
70a to the cooling medium side turning portion 71e. Then, the
refrigerant flows and turns around to the cooling medium tube
downstream side 712 on the leeward side in the outside air flow
direction in the upstream side cooling medium tube group 70a. The
refrigerant flowing from the cooling medium tube downstream portion
712 into the second cooling medium tank portion 722 flows from the
cooling medium tube upstream portion 711 on the leeward side in the
outside air flow direction A in the downstream side cooling medium
tube group 70b to the cooling medium side turning portion 71e.
Then, the refrigerant flows and turns around to the cooling medium
tube downstream portion 712 on the windward side in the flow
direction A of the outside air in the downstream side cooling
medium tube group 70b.
[0253] In the heat exchanger 16 of this embodiment, the refrigerant
tube upstream portion 611 of the upstream side refrigerant tube
group 60a and the cooling medium tube upstream portion 711 of the
upstream side cooling medium tube group 70a are arranged in
parallel in the lamination direction of the tubes 61 and 71. And,
the refrigerant tube downstream portion 612 of the upstream side
refrigerant tube group 60a and the cooling medium tube downstream
portion 712 of the upstream side cooling medium tube group 70a are
arranged in parallel in the lamination direction of the tubes 61
and 71.
[0254] In the heat exchanger 16 of this embodiment, the refrigerant
tube upstream portion 611 of the downstream side refrigerant tube
group 60b and the cooling medium tube upstream portion 711 of the
downstream side cooling medium tube group 70b are arranged in
parallel in the lamination direction of the tubes 61 and 71. And,
the refrigerant tube downstream portion 612 of the downstream side
refrigerant tube group 60b and the cooling medium tube downstream
portion 712 of the downstream side cooling medium tube group 70b
are arranged in parallel in the lamination direction of the tubes
61 and 71.
[0255] In the outdoor heat exchanging portion 60, the refrigerant
flows from the downstream side to the upstream side in the flow
direction of the outside air in the upstream side refrigerant tube
group 60a, and the refrigerant flows from the downstream side to
the upstream side in the flow direction of the outside air in the
downstream side refrigerant tube group 60b. Likewise, in the
radiator 70, the coolant flows from the upstream side to the
downstream side in the flow direction of the outside air in the
upstream side cooling medium tube group 70a, and flows from the
downstream side to the upstream side in the flow direction of the
outside air in the downstream side cooling medium tube group
70b.
[0256] Thus, the refrigerant tubes 61 and the cooling medium tubes
71 forming the upstream side refrigerant tube group 60a and the
upstream side cooling medium tube group 70a are designed to allow
the refrigerants to flow in the same direction from the windward
side to the leeward side along the flow direction A of the outside
air. The refrigerant tubes 61 and the cooling medium tubes 71
forming the downstream side refrigerant tube group 60b and the
downstream side cooling medium tube 70b, respectively, are designed
to allow the refrigerant and the coolant to flow in the same
direction from the leeward side to the windward side in the flow
direction A of the outside air.
[0257] The structures and operations of other components of the
heat pump cycle 10 including the heat exchanger 16 are the same as
those of the first embodiment. Like the first embodiment, the heat
exchanger 16 of this embodiment can also perform appropriate heat
exchange among three kinds of fluids, including refrigerant,
coolant, and outside air in each operation of the heat pump cycle
10. This embodiment can also improve the productivity of the heat
exchanger that can exchange heat among the three kinds of fluids
without increase in size.
[0258] Additionally, in the heat exchanger 16 of this embodiment,
the refrigerant tube upstream portion 611 of each refrigerant tube
61 forming the upstream side refrigerant tube group 60a is disposed
on the upstream side in the flow direction A of the outside air
with respect to the refrigerant tube downstream portion 612. And,
the cooling medium tube upstream portion 711 of each cooling medium
tube 71 forming the upstream side cooling medium tube group 70a is
disposed on the upstream side in the flow direction A of the
outside air with respect to the cooling medium tube downstream
portion 712.
[0259] In the operating state in which the refrigerant introduced
into the outdoor heat exchanging portion 60 and the cooling medium
introduced into the radiator 70 have the temperature higher than
that of the outside air, a difference in temperature between the
refrigerant and coolant is reduced on the refrigerant upstream side
of the upstream side refrigerant tube group 60a and on the coolant
upstream side of the upstream side cooling medium tube group 70a.
And differences in temperature between the refrigerant and outside
air and between the cooling medium and outside air can be ensured,
which can increase the amount of heat dissipation. As a result, a
difference in thermal strain between the refrigerant tube 61 and
the cooling medium tube 71 can be relieved.
[0260] In the heat exchanger 16 of this embodiment, the refrigerant
tube upstream portion 611 of each refrigerant tube 61 forming the
downstream side refrigerant tube group 60b is disposed on the
downstream side in the flow direction A of the outside air with
respect to the refrigerant tube downstream portion 612. And, the
cooling medium tube upstream portion 711 of each cooling medium
tube 71 forming the downstream side cooling medium tube group 70b
is disposed on the downstream side in the flow direction A of the
outside air with respect to the cooling medium tube downstream
portion 712.
[0261] In the operating state in which the refrigerant introduced
into the outdoor heat exchanging portion 60 and the cooling medium
introduced into the radiator 70 have the temperature higher than
that of the outside air, the heat contained in the refrigerant and
the coolant can be sufficiently dissipated into outside air on the
refrigerant downstream side of the downstream side refrigerant tube
group 60b and on the coolant downstream side of the downstream side
cooling medium tube group 70b. As a result, the performance of the
heat exchanger 16 can be improved.
[0262] As can be seen from the above description, the upstream side
refrigerant tube group 60a of this embodiment corresponds to an
upstream side first tube group described in the accompanying
claims. The downstream side refrigerant tube 60b of this embodiment
corresponds to a downstream side first tube group. The upstream
side cooling medium tube group 70a of this embodiment corresponds
to an upstream side second tube group described in the claims. The
downstream side cooling medium tube 70b of this embodiment
corresponds to a downstream side second tube group.
Other Embodiments
[0263] The present invention is not limited to the above
embodiments, and various modifications and changes can be made to
the disclosed embodiments without departing from the scope of the
invention.
[0264] (1) In the above embodiments, the heat exchanger 16 has the
tank and tube heat exchanger structure including two heat
exchanging portions 60 and 70 with the tubes (61, 71) and the
collection and distribution tanks (62, 72), by way of example. The
structure of each of the heat exchanging portions 60 and 70 is not
limited thereto.
[0265] Alternatively, for example, the heat exchanger may employ a
so-called drawn cup heat exchanger structure including lamination
of a plurality of sheets of plates via the outer fins 50. Each
plate includes a tube and a tank in communication with the tube
which are formed by bonding a pair of plate members with the
respective centers aligned with each other.
[0266] In such a drawn cup heat exchanger structure, the plates are
laminated to communicate the tanks of the plates with each other,
which can form the structure corresponding to each of the
refrigerant side header tank 62 and the cooling medium side header
tank 72 described in the above embodiments.
[0267] (2) In the above embodiments, the plates 63 and 73 are
coupled to the tanks 64 and 74, respectively, which partitions the
internal spaces into the collection spaces 62a and 72a, and the
distribution spaces 62b and 72b to thereby form the refrigerant
side header tank 62 and the cooling medium side header tank 72, by
way of example. The structures of the header tanks 62 and 72 are
not limited thereto.
[0268] For example, the header tank may be composed of two pipes,
and the internal space of each pipe may be a collection space or a
distribution space. This can improve the resistance to pressure of
each header tank.
[0269] (3) In the above embodiments, the refrigerant tubes 61 and
the cooling medium tubes 71 are alternately laminated or stacked,
by way of example. However, the arrangement of the refrigerant
tubes 61 and the cooling medium tubes 71 is not limited
thereto.
[0270] For example, in the heat exchanger 16 of the first and third
embodiments, as shown in FIG. 19(a), a plurality of (N pieces of)
refrigerant tubes 61 may be continuously laminated, and then a
plurality of (M pieces of) cooling medium tubes 71 may be
continuously laminated. At this time, the number of the cooling
tubes 61 may be equal or different to that of the cooling medium
tubes 71 continuously laminated thereon.
[0271] For example, in the heat exchanger 16 of the second
embodiment, as shown in FIGS. 19(b) to 19(d), the refrigerant tubes
61 may be positioned on the upstream side with respect to the flow
direction A of the outside air, while the cooling medium tubes 71
may be positioned on the downstream side.
[0272] FIGS. 19(a) to 19(d) schematically show the cross-sectional
views of the header tank of the heat exchanger 16 in the
longitudinal direction. In FIGS. 19(a) to 19(d), for easy
understanding, the refrigerant tubes 61 are indicated by hatching
with shaded areas, and the cooling medium tubes 71 are indicated by
dotted hatching.
[0273] In the arrangement including the refrigerant tubes 61 placed
adjacent to each other, or the cooling medium tubes 71 placed
adjacent to each other as shown in FIGS. 19(a) to 19(d), the outer
fins 50 may be desirably disposed in a space between the adjacent
refrigerant tubes 61, and between the adjacent cooling medium tubes
71.
[0274] In this way, the outer fins 50 are disposed in all spaces
formed between each of the tubes 61 and 71, and the adjacent
refrigerant tube 61 or cooling medium tube 71. Thus, the outer fins
50 promote the heat exchange between the outside air and the fluid
(refrigerant or coolant) flowing through the tubes 61 and 71, and
can relieve (reduce) a difference in thermal strain between the
refrigerant tube 61 and the cooling medium tube 71. As a result,
the breakdown of the heat exchanger 16 can be suppressed.
[0275] (4) In the above first embodiment, the cooling medium tube
upstream portion 711 of the cooling medium tube 71 among the
refrigerant tubes 61 and the cooling medium tubes 71 is positioned
on the upstream side in the flow direction A of the outside air
with respect to the cooling medium tube downstream portion 712, by
way of example, which does not limit the invention.
[0276] For example, the refrigerant tube upstream portion 611 of
the refrigerant tubes 61 among the refrigerant tubes 61 and the
cooling medium tubes 71 may be positioned on the upstream side in
the flow direction A of the outside air with respect to the
refrigerant tube downstream portion 612.
[0277] In the operating state in which the refrigerant introduced
into the outdoor heat exchanging portion 60 has the temperature
higher than that of each of the cooling medium and the outside air,
a difference in temperature between the refrigerant and the outside
air can be ensured on the upstream side of the refrigerant flow of
the refrigerant tubes 61 to increase the amount of heat
dissipation. Thus, the difference in temperature between the
refrigerant and coolant can be reduced, which can release the
difference in thermal strain between the refrigerant tubes 61 and
the cooling medium tubes 71. In this example, the refrigerant
corresponds to a "high-temperature side fluid"; the refrigerant
tube 61 to a "high-temperature side tube"; the refrigerant tube
upstream portion 611 of the refrigerant tube 61 to a
"high-temperature side tube upstream portion"; and the refrigerant
tube downstream portion 12 of the refrigerant tube 61 to a
"high-temperature side tube downstream portion". The coolant
corresponds to a "low-temperature side fluid"; the cooling medium
tube 71 to a "low-temperature side tube"; the cooling medium tube
upstream portion 711 of the cooling medium tube 71 to a
"low-temperature side tube upstream portion"; and the cooling
medium tube downstream portion 712 of the cooling medium tube 71 to
a "low-temperature side tube downstream portion".
[0278] (5) In the above first embodiment, the refrigerant tube
upstream portions 611 of the refrigerant tubes 61 and the cooling
medium tube downstream portions 712 of the cooling medium tubes 71
are arranged in the lamination direction of the tubes 61 and 71.
And the refrigerant tube downstream portions 612 and the cooling
medium tube upstream portions 711 are arranged in the lamination
direction of the tubes 61 and 71, by way of example. The invention
is not limited to the above arrangement.
[0279] For example, the refrigerant tube upstream portions 611 of
the refrigerant tubes 61 and the cooling medium tube upstream
portions 711 of the cooling medium tubes 71 may be arranged in the
lamination direction of the tubes 61 and 71, and the refrigerant
tube downstream portions 612 and the cooling medium tube downstream
portions 712 may be arranged in the lamination direction of the
tubes 61 and 71.
[0280] In such a structure, the refrigerant flowing through the
refrigerant tube 61 and the coolant flowing through the cooling
medium tube 71 have the flow directions opposed to each other in
the longitudinal direction of the respective tubes 61 and 71, and
the same flow direction in the flow direction of outside air (for
example, from the windward side to the leeward side, or the leeward
side to the windward side) (which is a partially parallel flow
structure).
[0281] The heat exchanger 16 with such a structure reduces the heat
exchanging capacity as compared to the heat exchanger 16 of the
first embodiment, but can decrease the difference in temperature
between the refrigerant flowing through the refrigerant tubes 61
and the cooling medium flowing through the cooling medium tubes 71
as a whole.
[0282] Referring to FIG. 20, the following will be the reason why
the difference in temperature between the refrigerant flowing
through the refrigerant tube 61 and the cooling medium flowing
through the cooling medium tube 71 can be reduced in the heat
exchanger 16 with the partially parallel flow structure. FIG. 20 is
an explanatory diagram for explaining how the difference in
structure between various types of heat exchangers affects the
difference in temperature between the refrigerant and coolant in
each tube. In FIG. 20, a solid line schematically indicates a
change in temperature of a high-temperature fluid (high-temperature
side fluid) of the refrigerant and the coolant (indicating an
inflow portion by a black circle and an outflow portion by a black
diamond). An alternate long and short dash line schematically
indicates a change in temperature of a low-temperature fluid
(low-temperature side fluid) in the heat exchanger 16 with a
partially parallel flow structure. An alternate long and two short
dashes line schematically indicates a change in temperature of a
low-temperature fluid in the opposite flow structure (heat
exchanger 16 described in the first embodiment). The alternate long
and short dash line and the alternate long and two short dashes
line respectively show the change in temperature on the following
conditions. In the operating state in which the temperature of the
outside air is lower than that of each of the refrigerant and the
coolant, an outflow temperature Tl2 of the low-temperature side
fluid flowing from the tube using the heat exchanger 16 with the
partially parallel flow structure is identical to an outflow
temperature Tl2' of the low-temperature side fluid flowing from the
tube using the heat exchanger 16 with the opposite flow
structure.
[0283] As mentioned above, the heat exchanger 16 with the partially
parallel flow structure has the heat exchanging capacity reduced as
compared to the heat exchanger 16 described in the first
embodiment. As indicated by the alternate long and short dash line
and the alternate long and two short dashes line in FIG. 20, in the
heat exchanger 16 with the partially parallel flow structure, the
inflow temperature Tl1 of the low-temperature side fluid flowing
into the tubes becomes higher than the inflow temperature Tl1' of
the low-temperature side fluid flowing into the heat exchanger 16
of the first embodiment.
[0284] That is, the difference in temperature .DELTA.T between the
inflow temperature Th1 of the high-temperature side fluid and the
inflow temperature Tl1 of the low-temperature side fluid flowing
into the heat exchanger 16 with the partially parallel flow
structure is small as compared to the difference in temperature
.DELTA.T' between the inflow temperature Tl1 of the
high-temperature side fluid and the inflow temperature Tl1' of the
low-temperature side fluid flowing into the heat exchanger 16 of
the first embodiment.
[0285] Thus, the heat exchanger 16 with the partially parallel flow
structure can reduce the difference in temperature between the
refrigerant flowing through the refrigerant tube 61 and the cooling
medium flowing through the cooling medium tube 71 as a whole, as
compared to the heat exchanger 16 of the first embodiment. As a
result, the heat exchanger can relieve the difference in thermal
strain between the refrigerant tube 61 and the cooling medium tube
71. This embodiment is applied to the operating state in which the
temperature of the outside air is lower than that of each of the
refrigerant and coolant, but the heat exchanger 16 with the
partially parallel flow structure can have the following effect
regardless of the relationship between the temperature of outside
air and that of refrigerant and coolant. That is, the heat
exchanger 16 with the partially parallel flow structure can reduce
the difference in temperature between the refrigerant flowing
through the refrigerant tube 61 and the cooling medium flowing
through the cooking medium tube 71 as a whole as compared to the
heat exchanger 16 of the first embodiment.
[0286] Further, in the heat exchanger 16 with the partially
parallel flow structure, the refrigerant tube upstream portion 611
and the cooling medium tube upstream portion 711 are desirably
positioned on the upstream side in the flow direction of the
outside air with respect to the refrigerant tube downstream portion
612 and the cooling medium tube downstream portion 712.
[0287] In the operating state in which the refrigerant introduced
into the outdoor heat exchanging portion 60 and the cooling medium
introduced into the radiator 70 have the temperature higher than
that of the outside air, the heat exchanger can ensure the
differences in temperature between the refrigerant and the outside
air, and between the coolant and the outside air to thereby
increase the amount of heat dissipation. As a result, the
difference in thermal strain between the refrigerant tube 61 and
the cooling medium tube 71 can be relieved to suppress the
breakdown of the heat exchanger 16.
[0288] (6) In the above first embodiment, the refrigerant of the
heat pump cycle 10 is used as the first fluid, the coolant of the
coolant circulation circuit 40 is used as the second fluid, and the
outside air blown by the blower fan 17 is used as the third fluid,
but the first to third fluids are not limited thereto. For example,
like the third embodiment, the air in the vehicle interior may be
used as the third fluid.
[0289] For example, the first fluid may be a high-pressure side
refrigerant or a low-pressure side refrigerant in the heat pump
cycle 10.
[0290] For example, the second fluid may be a coolant for cooling
electric devices, such as an engine or an inverter for supplying
electric power to an electric motor MG for traveling.
Alternatively, the second fluid may be oil for cooling, the second
heat exchanging portion may serve as an oil cooler, and the second
fluid for use may be a heat storage agent, a cooling storage agent,
or the like.
[0291] The first to third fluids are not limited to fluids whose
properties or components are different from each other. The first
to third fluids may be fluids which differ in temperature or state,
such as a gas phase or a liquid phase even when those fluids have
the same properties or components. For example, the first fluid for
use may be a high-pressure side refrigerant in the heat pump cycle
10, and the second fluid for use may be a low-pressure side
refrigerant in the heat pump cycle 10. For example, when the heat
exchanger is provided with different circuits adapted for
circulating the coolant for cooling the engine and for circulating
the coolant for cooling the invertor, the first fluid for use is a
coolant for the engine, and the second fluid for use is a coolant
for the inverter.
[0292] The relationship between the temperatures of the first to
third fluids is desirably as follows: the temperature of the third
fluid is lower than that of one of the first and second fluids
having a higher temperature (high-temperature side fluid), and
higher than that of the other having a lower temperature
(low-temperature side fluid). Such a temperature relationship
decreases the temperature of the high-temperature side fluid and
increases the temperature of the low-temperature side fluid in the
heat exchanger 16, which can decrease the difference in temperature
between the first fluid and the second fluid. As a result, the
difference in thermal strain between the tubes 61 and 71 can be
relieved to thereby effectively suppress the breakdown of the heat
exchanger 16.
[0293] When the heat pump cycle 10 to which the heat exchanger 16
of the invention is applied is used in a stationary air
conditioner, a cooling storage cabinet, a cooling and heating
device for a vending machine, or the like, the second fluid may be
a coolant for cooling the engine and electric motor which serve as
a driving source of the compressor of the heat pump cycle 10, as
well as other electric devices.
[0294] In the above embodiments, the heat exchanger 16 of the
invention is applied to the heat pump cycle (refrigeration cycle),
by way of example. The applications of the heat exchanger 16 of the
invention are not limited thereto. That is, the heat exchanger 16
of the invention can be widely applied to any devices for
exchanging heat among three kinds of fluids and the like.
[0295] (7) In the above embodiments, the refrigerant tubes 61 of
the outdoor heat exchanging portion 60, the cooling medium tubes 71
of the radiator 70, and the outer fins 50 are formed of an aluminum
alloy (metal) and brazed together, by way of example. The outer fin
50 may be formed of material with excellent heat conductivity (for
example, carbon nanotube, or the like), and may be bonded by any
bonding means, such as adhesive or the like.
[0296] FIG. 21 schematically shows a partial perspective view of a
heat exchanger 16 according to another embodiment. FIGS. 22(a),
22(b), and 22(c) are explanatory diagrams for explaining an outer
fin 50 in another embodiment. FIG. 22(a) is a partial front view of
the outer fin 50, FIG. 22(b) is a cross-sectional view taken along
the line XXIIB-XXIIB of FIG. 22(a), and FIG. 22(c) is an enlarged
view of an XXIIC part of FIG. 22(a).
[0297] When the outer fin 50 is bonded with the tubes 61 and 71
like the above respective embodiments, as shown in FIGS. 21, 22(a),
22(b), and 22(c), the outer fin 50 is desirably provided with a
plurality of slits 50a for locally weakening the rigidity of the
outer fin 50. The slit 50a can be formed of a through hole
penetrating the outer fin 50, or a cutout formed at the peripheral
edge of the outer fin 50.
[0298] Thus, each slit 50a of the outer fin 50 can absorb the
stress acting on the tubes 61 and 71 when there is the difference
in thermal strain between the tubes 61 and 71. Further, the outer
fins 50 with the slits 50a can suppress the breakdown of the heat
exchanger 16 within a partial range when the difference in thermal
strain between the tubes 61 and 71 occurs.
[0299] (8) In the above first embodiment, in the tube and tank
temporary fixing step, the refrigerant tubes 61 and the cooling
medium tubes 71 are temporarily fixed together with the inner fins
65 and 75 stuck in the plates 61a, 61b, 71a, and 71b, by way of
example. Alternatively, the plates 61a, 61b, 71a, and 71b may be
provided with positioning portions for the inner fins 65 and
75.
[0300] Such positioning portions may be formed of protrusions that
protrude inward, for example, from the refrigerant flow path 61c,
the cooling medium flow path 71c, the turning portions 61e and 71e,
and the enlarging portions 61f and 71f.
[0301] (9) The above second and third embodiments do not describe
the inner fins 65 and 75 disposed inside the refrigerant tubes 61
and the cooling medium tubes 71. However, when the inner fins 65
and 75 are intended to be employed, the flat tubes are bent, and
then the fins are desirably inserted into fluid flow paths on the
upstream side and the downstream side of each of the turning
portions 61e and 71e. Thus, the inner fins can be prevented from
being deformed upon bending the flat tube.
[0302] (10) In the above embodiments, the electric three-way valve
42 is employed as circuit switching means for switching among the
cooling medium circuits of the coolant circulation circuit 40, by
way of example. However, the circuit switching means is not limited
thereto. For example, a thermostatic valve may be employed. The
thermostatic valve is a cooling medium temperature responsive valve
composed of a mechanical system that is designed to open and close
a cooling medium passage by displacing a valve body by use of a
thermowax (temperature sensing member) whose volume is changed
depending on the temperature. Thus, the thermostatic valve can be
used to remove the coolant temperature sensor 52.
[0303] (11) Although in the above embodiments, the refrigerant for
use is the normal flon-based refrigerant by way of example, the
kind of the refrigerant is not limited thereto. The refrigerant for
use may be natural refrigerant, such as carbon dioxide, or a
hydrocarbon-based refrigerant. Further, the heat pump cycle 10 may
be a supercritical refrigeration cycle in which the pressure of
refrigerant discharged from the compressor 11 is equal to or higher
than the critical pressure of the refrigerant.
[0304] The present invention has been disclosed with reference to
the preferred embodiments. However, it is to be understood that the
present invention is not limited to the above preferred embodiments
and the structures described above.
[0305] The present invention is intended to cover various modified
examples and equivalent arrangements thereto. In addition, other
preferred embodiments which includes one additional element or
which loses one element with respect to the disclosed embodiments,
or various other combinations of the embodiments also fall within
the scope and spirit of the present invention.
* * * * *