U.S. patent application number 14/613359 was filed with the patent office on 2015-08-27 for air-conditioning apparatus for vehicle.
This patent application is currently assigned to KEIHIN THERMAL TECHNOLOGY CORPORATION. The applicant listed for this patent is KEIHIN THERMAL TECHNOLOGY CORPORATION. Invention is credited to Motoyuki TAKAGI.
Application Number | 20150241080 14/613359 |
Document ID | / |
Family ID | 53782588 |
Filed Date | 2015-08-27 |
United States Patent
Application |
20150241080 |
Kind Code |
A1 |
TAKAGI; Motoyuki |
August 27, 2015 |
AIR-CONDITIONING APPARATUS FOR VEHICLE
Abstract
An air-conditioning apparatus for a vehicle includes an
evaporator and a temperature sensor for detecting the temperature
of the evaporator. The evaporator includes three tube groups
provided in a leeward tube row, and two tube groups provided in a
windward tube row. The flow direction of refrigerant within heat
exchange tubes of a farthest tube group of the leeward tube row
farthest from a refrigerant inlet is the same as that within heat
exchange tubes of a farthest tube group of the windward tube row
farthest from a refrigerant outlet. A single path is formed by the
two farthest tube groups. The temperature sensor is disposed to
detect the temperature of a portion of the evaporator where the
farthest tube group of the leeward tube row is provided. The
air-conditioning apparatus prevents the temperature of air from
greatly changing due to turning on and off of a compressor.
Inventors: |
TAKAGI; Motoyuki;
(Oyama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KEIHIN THERMAL TECHNOLOGY CORPORATION |
Oyama-shi |
|
JP |
|
|
Assignee: |
KEIHIN THERMAL TECHNOLOGY
CORPORATION
Oyama-shi
JP
|
Family ID: |
53782588 |
Appl. No.: |
14/613359 |
Filed: |
February 4, 2015 |
Current U.S.
Class: |
62/216 |
Current CPC
Class: |
F24F 2110/10 20180101;
F24F 11/30 20180101; B60H 1/00335 20130101; B60H 1/3227 20130101;
B60H 1/00792 20130101 |
International
Class: |
F24F 11/00 20060101
F24F011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 21, 2014 |
JP |
2014-031986 |
Claims
1. An air-conditioning apparatus for a vehicle comprising a
compressor which uses an engine as a drive source and is connected
to the engine through clutch means; a condenser for cooling
refrigerant compressed by the compressor; a pressure reducer for
reducing the pressure of the refrigerant cooled by the condenser;
an evaporator for evaporating the refrigerant whose pressure has
been reduced by the pressure reducer; and a temperature sensor for
detecting the temperature of the evaporator, the air-conditioning
apparatus controlling the temperature of the evaporator by turning
the compressor on and off on the basis of the temperature detected
by the temperature sensor, wherein the evaporator includes leeward
and windward tube rows which are juxtaposed in an air-passing
direction and each of which is composed of a plurality of heat
exchange tubes disposed at predetermined intervals in a direction
orthogonal to the air-passing direction such that their
longitudinal directions coincide with a vertical direction; the
leeward tube row includes three or more tube groups each composed
of a plurality of heat exchange tubes, and the windward tube row
includes tube groups the number of which is one less than the
number of the tube groups of the leeward tube row and each of which
is composed of a plurality of heat exchange tubes; upper and lower
ends of the heat exchange tubes of the leeward tube row communicate
with leeward upper and lower header sections, respectively, and
upper and lower ends of the heat exchange tubes of the windward
tube row communicate with windward upper and lower header sections,
respectively; a refrigerant inlet is provided at one end of one
leeward header section selected from the leeward upper and lower
header sections, and a refrigerant outlet is provided at one end of
one windward header section selected from the windward upper and
lower header sections in such a manner that the refrigerant outlet
and inlet are located side by side in the air-passing direction. a
flow direction of refrigerant within the heat exchange tubes of a
farthest tube group of the leeward tube row located at a position
farthest from the refrigerant inlet is the same as a flow direction
of refrigerant within the heat exchange tubes of a farthest tube
group of the windward tube row located at a position farthest from
the refrigerant outlet; a single path is formed by the two farthest
tube groups which are juxtaposed in the air-passing direction and
which are the same in the flow direction of refrigerant within the
heat exchange tubes; and a single temperature sensor is disposed on
the evaporator so as to detect the temperature of a portion of the
evaporator where the farthest tube group of the leeward tube row is
provided.
2. An air-conditioning apparatus for a vehicle according to claim
1, wherein the temperature sensor is composed of a thermistor, and
is attached to a fin disposed between adjacent heat exchange tubes
of the farthest tube group of the leeward tube row.
3. An air-conditioning apparatus for a vehicle according to claim
1, wherein first through third tube groups each composed of a
plurality of heat exchange tubes are provided in the leeward tube
row of the evaporator in such a manner that the first through third
tube groups are arranged in this order from one end of the leeward
tube row on the refrigerant inlet side toward the other end of the
leeward tube row; fourth and fifth tube groups each composed of a
plurality of heat exchange tubes are provided in the windward tube
row of the evaporator in such a manner that the fourth and fifth
tube groups are arranged in this order from one end of the windward
tube row opposite the refrigerant outlet toward the other end of
the windward tube row located on the refrigerant outlet side; a
predetermined number of sections are provided in each of the
leeward upper and lower header sections and the windward upper and
lower header sections, whereby the first tube group serves as a
first path where the refrigerant flows within the heat exchange
tubes from one of upper and lower sides where the refrigerant inlet
is located to the opposite side, the second tube group serves as a
second path where the refrigerant flows within the heat exchange
tubes in a direction opposite the flow direction in the first path,
the third and fourth tube groups serve as a third path where the
refrigerant flows within the heat exchange tubes in the same
direction as the flow direction in the first path, and the fifth
tube group serves as a fourth path where the refrigerant flows
within the heat exchange tubes in the direction opposite the flow
direction in the first path; and the third and fourth tube groups
which are the same in the flow direction of the refrigerant within
the heat exchange tubes are juxtaposed in the air-passing
direction.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to an air-conditioning
apparatus for a vehicle, which is a refrigeration cycle to be
mounted on an automobile, for example.
[0002] Herein and in the appended claims, the upper and lower sides
of FIGS. 2 and 3 will be referred to as "upper" and "lower,"
respectively.
[0003] A widely known air-conditioning apparatus for a vehicle
(hereinafter may be referred to as a "vehicular air-conditioning
apparatus") includes a compressor which uses an engine as a drive
source and is connected to the engine through clutch means; a
condenser for cooling refrigerant compressed by the compressor; a
pressure reducer for reducing the pressure of the refrigerant
cooled by the condenser; an evaporator for evaporating the
refrigerant whose pressure has been reduced by the pressure
reducer; and a temperature sensor for detecting the temperature of
the evaporator. The vehicular air-conditioning apparatus controls
the temperature of the evaporator by means of turning the
compressor on and off on the basis of the temperature detected by
the temperature sensor, to thereby prevent generation of a large
difference between the temperature of air blown out into a vehicle
cabin when the compressor is on (i.e., operated) and the
temperature of air blown out into the vehicle cabin when the
compressor is off (i.e., not operated).
[0004] Such a vehicular air conditioning apparatus proposed in the
past (see Japanese Patent Application Laid-Open (kokai) No.
2004-268769) has the following structure. The evaporator of the
vehicular air conditioning apparatus includes two tube rows
juxtaposed in an air-passing direction. Each tube row includes a
plurality of heat exchange tubes which are disposed such that their
longitudinal directions coincide with the vertical direction and
they are spaced from one another in a direction orthogonal to the
air-passing direction. A fin is disposed to extend over an
air-passing gap between adjacent heat exchange tubes of one tube
row and over an air-passing gap between corresponding adjacent heat
exchange tubes of the other tube row such that the fin is shared by
the heat exchange tubes of the two tube rows. Upper and lower end
portions of the heat exchange tubes of the leeward tube row are
connected to leeward upper and lower header sections, respectively,
and upper and lower end portions of the heat exchange tubes of the
windward tube row are connected to windward upper and lower header
sections, respectively. A refrigerant inlet is provided at one end
of the leeward upper header section, and a refrigerant outlet is
provided at one end of the windward upper header section, which end
is located on the same side as the one end of the leeward upper
header section. The leeward tube row includes first through fourth
tube groups each composed of a plurality of heat exchanges and
arranged in this order from the refrigerant inlet side toward the
opposite end side. The windward tube row includes fifth through
eighth tube groups each composed of a plurality of heat exchanges
and arranged in this order from the end opposite the refrigerant
outlet toward the refrigerant outlet. The eighth tube group is
located windward of the first tube group, the seventh tube group is
located windward of the second tube group, the sixth tube group is
located windward of the third tube group, and the seventh tube
group is located windward of the fourth tube group. Each tube group
forms a single path. In each tube group, the refrigerant flows
through the heat exchange tubes in the same direction. The
refrigerant flow direction of the heat exchange tubes of a certain
tube group is opposite the refrigerant flow direction of the heat
exchange tubes of another tube group adjacent to the certain tube
group. A first temperature sensor is attached to a fin disposed
between adjacent heat exchange tubes of the first tube group, and a
second temperature sensor is attached to a fin disposed between
adjacent heat exchange tubes of the fourth tube group.
[0005] In the vehicular air-conditioning apparatus described in the
above-mentioned publication, when the temperature of the fins
disposed in the first tube group of the evaporator detected by the
first temperature sensor becomes equal to or lower than an off-side
target temperature, the clutch means is brought into a disconnected
or disengaged state so as to stop the compressor, and, when the
temperature of the fins disposed in the fourth tube group of the
evaporator detected by the second temperature sensor elevates to an
on-side target temperature higher than the off-side target
temperature by a predetermined temperature, the clutch means is
brought into a connected or engaged state so as to return the
compressor to the operated state.
[0006] However, since a super heat region is present in the eighth
tube group, when the compressor is off, the temperature of the fins
disposed in the eighth tube group of the evaporator becomes
considerably high. Accordingly, when the compressor is turned on, a
relatively long period of time is required for the temperature of
the fins disposed in the first tube group of the evaporator to
become equal to or lower than the off-side target temperature, and
the temperatures of the heat exchange tubes and the fins disposed
in other tube groups (e.g., the fourth and fifth tube groups) of
the evaporator decrease. In such a case, condensed water may
freeze. As a result of freezing of condensed water, an offensive
smell called "freezing odor" may be produced.
[0007] Also, since the vehicular air-conditioning apparatus
disclosed in the above-mentioned publication uses two temperature
sensors, the number of components increases, which results in an
increase in cost and an increase in the number of man-hours of
assembling operation. In addition, its control system may become
complex.
SUMMARY OF THE INVENTION
[0008] An object of the present invention is to solve the
above-described problem and to provide an air-conditioning
apparatus for a vehicle which can prevent freezing of condensed
water on the surface of an evaporator and which can reduce the
number of components.
[0009] To achieve the above object, the present invention comprises
the following mode.
[0010] 1) An air-conditioning apparatus for a vehicle comprising a
compressor which uses an engine as a drive source and is connected
to the engine through clutch means; a condenser for cooling
refrigerant compressed by the compressor; a pressure reducer for
reducing the pressure of the refrigerant cooled by the condenser;
an evaporator for evaporating the refrigerant whose pressure has
been reduced by the pressure reducer; and a temperature sensor for
detecting the temperature of the evaporator, the air-conditioning
apparatus controlling the temperature of the evaporator by turning
the compressor on and off on the basis of the temperature detected
by the temperature sensor. The evaporator includes leeward and
windward tube rows which are juxtaposed in an air-passing direction
and each of which is composed of a plurality of heat exchange tubes
disposed at predetermined intervals in a direction orthogonal to
the air-passing direction such that their longitudinal directions
coincide with a vertical direction. The leeward tube row includes
three or more tube groups each composed of a plurality of heat
exchange tubes, and the windward tube row includes tube groups the
number of which is one less than the number of the tube groups of
the leeward tube row and each of which is composed of a plurality
of heat exchange tubes. Upper and lower ends of the heat exchange
tubes of the leeward tube row communicate with leeward upper and
lower header sections, respectively, and upper and lower ends of
the heat exchange tubes of the windward tube row communicate with
windward upper and lower header sections, respectively. A
refrigerant inlet is provided at one end of one leeward header
section selected from the leeward upper and lower header sections,
and a refrigerant outlet is provided at one end of one windward
header section selected from the windward upper and lower header
sections in such a manner that the refrigerant outlet and inlet are
located side by side in the air-passing direction. A flow direction
of refrigerant within the heat exchange tubes of a farthest tube
group of the leeward tube row located at a position farthest from
the refrigerant inlet is the same as a flow direction of
refrigerant within the heat exchange tubes of a farthest tube group
of the windward tube row located at a position farthest from the
refrigerant outlet. A single path is formed by the two farthest
tube groups which are juxtaposed in the air-passing direction and
which are the same in the flow direction of refrigerant within the
heat exchange tubes. A single temperature sensor is disposed on the
evaporator so as to detect the temperature of a portion of the
evaporator where the farthest tube group of the leeward tube row is
provided.
[0011] 2) An air-conditioning apparatus for a vehicle according to
par. 1), wherein the temperature sensor is composed of a
thermistor, and is attached to a fin disposed between adjacent heat
exchange tubes of the farthest tube group of the leeward tube
row.
[0012] 3) An air-conditioning apparatus for a vehicle according to
par. 1), wherein first through third tube groups each composed of a
plurality of heat exchange tubes are provided in the leeward tube
row of the evaporator in such a manner that the first through third
tube groups are arranged in this order from one end of the leeward
tube row on the refrigerant inlet side toward the other end of the
leeward tube row; fourth and fifth tube groups each composed of a
plurality of heat exchange tubes are provided in the windward tube
row of the evaporator in such a manner that the fourth and fifth
tube groups are arranged in this order from one end of the windward
tube row opposite the refrigerant outlet toward the other end of
the windward tube row located on the refrigerant outlet side; a
predetermined number of sections are provided in each of the
leeward upper and lower header sections and the windward upper and
lower header sections, whereby the first tube group serves as a
first path where the refrigerant flows within the heat exchange
tubes from one of upper and lower sides where the refrigerant inlet
is located to the opposite side, the second tube group serves as a
second path where the refrigerant flows within the heat exchange
tubes in a direction opposite the flow direction in the first path,
the third and fourth tube groups serve as a third path where the
refrigerant flows within the heat exchange tubes in the same
direction as the flow direction in the first path, and the fifth
tube group serves as a fourth path where the refrigerant flows
within the heat exchange tubes in the direction opposite the flow
direction in the first path; and the third and fourth tube groups
which are the same in the flow direction of the refrigerant within
the heat exchange tubes are juxtaposed in the air-passing
direction.
[0013] According to the air-conditioning apparatus for a vehicle of
pars. 1) through 3), the refrigerant having flowed into the
evaporator through the refrigerant inlet thereof flows over
substantially the same period of time and the same distance before
reaching the farthest tube group of the leeward tube row and before
reaching the farthest tube group of the windward tube row.
Therefore, when the compressor is switched from the off state to
the on state, the heat exchange tubes of the two farthest tube
groups of the evaporator are cooled uniformly. As a result, when
the compressor is turned on, the temperature of a portion of the
evaporator where the third tube group is present becomes equal to
or lower than an off-side target temperature within a relatively
short period of time. Accordingly, it is possible to prevent
occurrence of a problem in that the temperature of a portion of the
evaporator where the tube groups, excluding the farthest tube group
of the leeward tube row and the farthest tube group of the wind
tube row, are present decreases, and condensed water freezes. As a
result, production of an offensive smell called freezing odor,
which is produced as a result of freezing of condensed water, can
be restrained.
[0014] Also, when the compressor is switched from the off state to
the on state, the temperature of a portion of the evaporator where
the nearest tube group of the leeward tube row closest to the
refrigerant inlet is present is apt to decrease sharply. However,
the decrease in the temperature of the portion of the evaporator
where the nearest tube group of the leeward tube row is present,
which decrease occurs when the compressor is switched from the off
state to the on state, is mitigated for the following reason. When
the compressor is off, due to presence of a super heat region in
the nearest tube group of the windward tube row closest to the
refrigerant outlet, the temperature of a portion of the evaporator
where the nearest tube group of the windward tube row is present
becomes considerably high. This high temperature mitigates the
decrease in the temperature of the portion of the evaporator where
the nearest tube group of the leeward tube row is present.
Accordingly, when the compressor is on, the decrease in the
temperature of the portion of the evaporator where the nearest tube
group of the leeward tube row is present is restrained, whereby
freezing of condensed water is restrained.
[0015] Also, since the air-conditioning apparatus for a vehicle of
pars. 1) through 3) uses a single temperature sensor only, the
number of components decreases. Therefore, cost can be lowered, and
the number of man-hours of assembling operation can be decreased.
In addition, the control system of the air-conditioning apparatus
becomes simple.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a partially cut-away perspective view showing the
overall structure of an evaporator used in an air-conditioning
apparatus for a vehicle of the present invention;
[0017] FIG. 2 is a partially omitted sectional view taken along
line A-A of FIG. 1;
[0018] FIG. 3 is a partially omitted sectional view taken along
line B-B of FIG. 1; and
[0019] FIG. 4 is a view showing the flow of refrigerant in the
evaporator of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] An embodiment of the present invention will next be
described with reference to the drawings. In the embodiment to be
described later, air flows in a direction indicated by an arrow X
in the drawings, passes through an evaporator, and is fed into the
cabin of a vehicle on which a vehicular air-conditioning apparatus
is mounted.
[0021] In the following description, the left and right sides when
viewed from the leeward side toward the windward side (the left and
right sides of FIGS. 2 and 3) will be referred to as "left" and
"right," respectively.
[0022] The term "aluminum" as used in the following description
encompasses aluminum alloys in addition to pure aluminum.
[0023] FIG. 1 shows the overall structure of an evaporator used in
a vehicular air-conditioning apparatus of the present invention,
FIGS. 2 and 3 schematically show the structure of the evaporator,
and FIG. 4 shows the flow of refrigerant in the evaporator of FIG.
1. Notably, since the structure of the vehicular air-conditioning
apparatus is well known, it is not shown in the drawings.
[0024] The vehicular air-conditioning apparatus includes a
compressor which uses an engine as a drive source and is connected
to the engine through clutch means; a condenser for cooling
refrigerant compressed by the compressor; a pressure reducer for
reducing the pressure of the refrigerant cooled by the condenser;
an evaporator 1 for evaporating the refrigerant whose pressure has
been reduced by the pressure reducer; and a temperature sensor 2
which is composed of a thermistor and which detects the temperature
of the evaporator 1. The vehicular air-conditioning apparatus
controls the temperature of the evaporator 1 by means of turning
the compressor on and off on the basis of the temperature detected
by the temperature sensor 2.
[0025] As shown in FIGS. 1 through 3, the evaporator 1 includes a
leeward tube row 4 and a windward tube row 5. Each of the leeward
tube row 4 and the windward tube row 5 includes a plurality of flat
heat exchange tubes 3 made of aluminum and disposed at
predetermined intervals in a left-right direction (a direction
orthogonal to an air-passing direction indicated by the arrow X in
FIG. 1) in such a manner that their width directions coincide with
the air-passing direction and their longitudinal directions
coincide with the vertical direction. A leeward upper header
section 6 and a leeward lower header section 7 which are made of
aluminum are disposed at the upper and lower ends, respectively, of
the heat exchange tubes 3 of the leeward tube row 4 in such a
manner that their longitudinal directions coincide with the
left-right direction (the direction in which the heat exchange
tubes 3 are juxtaposed). All the heat exchange tubes 3 of the
leeward tube row 4 are connected to the leeward upper header
section 6 and the leeward lower header section 7. A windward upper
header section 8 and a windward lower header section 9 which are
made of aluminum are disposed at the upper and lower ends,
respectively, of the heat exchange tubes 3 of the windward tube row
5 in such a manner that their longitudinal directions coincide with
the left-right direction (the direction in which the heat exchange
tubes 3 are juxtaposed). All the heat exchange tubes 3 of the
windward tube row 5 are connected to the windward upper header
section 8 and the windward lower header section 9. The number of
the heat exchange tubes 3 of the leeward tube row 4 is equal to the
number of the heat exchange tubes 3 of the windward tube row 5.
[0026] The evaporator 1 includes a plurality of corrugated fins 12
made of aluminum. Each corrugated fin 12 is disposed to extend over
an air-passing gap 11 between adjacent heat exchange tubes 3 of the
leeward tube row 4 and an air-passing gap 11 between corresponding
adjacent heat exchange tubes 3 of the windward tube row 5 such that
the fin 12 is shared by the corresponding heat exchange tubes 3 of
the two tube rows 4 and 5. Each corrugated fin 12 is brazed to the
corresponding heat exchange tubes 3. Also, the corrugated fins 12
are disposed outward of the heat exchange tubes 3 at the left and
right ends such that the fins 12 are shared by the corresponding
heat exchange tubes 3 of the two tube rows 4 and 5, and are brazed
to these heat exchange tubes 3. A side plate 13 made of aluminum is
disposed on the outer side of each of the corrugated fins 12 at the
left and right ends, and is brazed to the corresponding corrugated
fin 12. Each corrugated fin 12 has crest portions, trough portions,
and connection portions connecting the crest portions and the
trough portions. The gaps between the heat exchange tubes 3 at the
left and right ends and the corresponding side plates 13 also serve
as air-passing gaps 11. Air having passed through the air-passing
gaps 11 each located between adjacent heat exchange tubes 3 of the
two tube rows 4 and 5 is fed into the cabin of the vehicle on which
the vehicular air-conditioning apparatus is mounted.
[0027] As shown in FIGS. 2 through 4, the leeward tube row 4
includes an odd number (at least three) of tube groups (in the
present embodiment, first through third tube groups 14, 15, and 16)
each composed of a plurality of continuously juxtaposed heat
exchange tubes 3, and the windward tube row 5 includes tube groups
(in the present embodiment, fourth and fifth tube groups 17 and 18)
the number of which is one less than the number of the tube groups
14, 15, and 16 of the leeward tube row 4 and each of which is
composed of a plurality of continuously juxtaposed heat exchange
tubes 3.
[0028] The temperature sensor 2, which is composed of, for example,
a thermistor, is attached to adjacent connection portions of a
certain corrugated fin 12 disposed in a certain air-passing gap 11
of the third tube group 16 such that the temperature sensor 2 is
located between the adjacent connection portions. The temperature
sensor 2 detects the temperature of the corrugated fins 12 disposed
in the third tube group 16 of the evaporator 1. When the
temperature detected by the temperature sensor 2 becomes equal to
or lower than an off-side target temperature, the clutch means is
brought into a disconnected or disengaged state, whereby the
compressor is stopped. When the temperature detected by the
temperature sensor 2 elevates to an on-side target temperature
higher than the off-side target temperature by a predetermined
temperature, the clutch means is brought into a connected or
engaged state, whereby operation of the compressor is resumed.
[0029] In the leeward tube row 4, the first tube group 14 is
located at the right end, the second tube group 15 is located at
the center in the left-right direction, and the third tube group 16
is located at the left end. In the windward tube row 5, the fourth
tube group 17 is located on the left side, and the fifth tube group
18 is located on the right side. The number of the heat exchange
tubes 3 constituting the second tube group 15 is equal to or
greater than the number of the heat exchange tubes 3 constituting
the first tube group 14, and the total number of the heat exchange
tubes 3 of the two tube groups 14 and 15 is equal to the number of
the heat exchange tubes 3 constituting the fifth tube group 18. The
number of the heat exchange tubes 3 constituting the third tube
group 16 and the number of the heat exchange tubes 3 constituting
the fourth tube group 17 are equal to each other. As a result, the
total width of the first and second tube groups 14 and 15 as
measured in the left-right direction is the same as the width of
the fifth tube group 18 as measured in the left-right direction,
and the width of the third tube group 16 as measured in the
left-right direction is the same as the width of the fourth tube
group 17 as measured in the left-right direction. The first tube
group 14 of the leeward tube row 4 located at the right end forms a
first path through which the refrigerant first flows, and the fifth
tube group 18 of the windward tube row 5 located on the right side
forms a last path through which the refrigerant flows last.
[0030] The leeward upper header section 6 and the windward upper
header section 8 are provided by, for example, dividing the
interior of a single tank 19 into two spaces in the air-passing
direction by a partition 19a extending in the left-right direction.
Similarly, the leeward lower header section 7 and the windward
lower header section 9 are provided by, for example, dividing the
interior of a single tank 21 into two spaces in the air-passing
direction by a partition 21a extending in the left-right
direction.
[0031] The interior of the leeward upper header section 6 is
divided by a partition 6a into a plurality of spaces arranged in
the left-right direction. Thus, a first section 22 with which the
heat exchange tubes 3 of the first tube group 14 communicate and a
second section 23 with which the heat exchange tubes 3 of the
second and third tube groups 15 and 16 communicate are provided in
the leeward upper header section 6. A refrigerant inlet 24 is
provided at the right end of the first section 22.
[0032] The interior of the leeward lower header section 7 is
divided by a partition 7a into a plurality of spaces arranged in
the left-right direction. Thus, a third section 25 with which the
heat exchange tubes 3 of the first and second tube groups 14 and 15
communicate and a fourth section 26 with which the heat exchange
tubes 3 of the third tube group 16 communicate are provided in the
leeward lower header section 7.
[0033] The interior of the windward upper header section 8 is
divided by a partition 8a into a plurality of spaces arranged in
the left-right direction. Thus, a fifth section 27 with which the
heat exchange tubes 3 of the fourth tube group 17 communicate and a
sixth section 28 with which the heat exchange tubes 3 of the fifth
tube group 18 communicate are provided in the windward upper header
section 8. A refrigerant outlet 29 is provided at the right end of
the sixth section 28.
[0034] The windward lower header section 9 includes a seventh
section 32 with which the heat exchange tubes 3 of the fourth tube
group 17 and the fifth tube group 18 communicate and which extends
over the entirety of the windward lower header section 9.
[0035] Communication is established, thorough a communication
opening 33 provided in the partition 19a, between the fifth section
27 of the windward upper header section 8 and a portion of the
second section 23 of the leeward upper header section 6, with which
portion the heat exchange tubes 3 of the third tube group 16
communicate. Also, communication is established, thorough a
plurality of communication openings 34 provided in the partition
21a, between the fourth section 26 of the leeward lower header
section 7 and a portion of the seventh section 32 of the windward
lower header section 9, with which portion the heat exchange tubes
3 of the fourth tube group 17 communicate.
[0036] The first through fifth tube groups 14, 15, 16, 17, and 18
are provided in the leeward tube row 4 and the windward tube row 5
as described above. Also, the refrigerant inlet 24, the refrigerant
outlet 29, the first through seventh sections 22, 23, 25, 26, 27,
28, and 32, and the communication openings 33 and 34 are provided
in the two leeward header sections 6 and 7 and the two windward
header sections 8 and 9 as described above. As a result, the
refrigerant flows from the upper side toward the lower side within
the heat exchange tubes 3 of the first tube group 14, the third
tube group 16, and the fourth tube group 17, and the refrigerant
flows from the lower side toward the upper side within the heat
exchange tubes 3 of the second tube group 15 and the fifth tube
group 18. Each of the first tube group 14, the second tube group
15, and the fifth tube group 18 forms a single heat exchange path,
and the third and fourth (two) tube groups 16 and 17 form a single
heat exchange path.
[0037] Accordingly, as shown in FIG. 4, the refrigerant whose
pressure has been reduced by the pressure reducer flows into the
first section 22 through the refrigerant inlet 24, flows along two
routes as follows, and flows out from the refrigerant outlet 29 of
the sixth section 28 toward the compressor. The first route extends
through the first section 22, the first tube group 14, the third
section 25, the second tube group 15, the second section 23, the
fourth tube group 16, the fourth section 26, the communication
openings 34, the seventh section 32, the fifth tube group 18, and
the sixth section 28. The second route extends through the first
section 22, the first tube group 14, the third section 25, the
second tube group 15, the second section 23, the communication
opening 33, the fifth section 27, the fourth tube group 17, the
seventh section 32, the fifth tube group 18, and the sixth section
28. The first tube group 14 forms a first path, the second tube
group 15 forms a second path, the third and fourth tube groups 16
and 17 form a third path, and the eighth tube group 18 forms a
fourth path.
[0038] In the above-described vehicular air-conditioning apparatus,
the gas-liquid mixed phase refrigerant having passed through the
compressor, the condenser, and the expansion valve passes through
the refrigerant inlet 24, and enters the first section 22 of the
leeward upper header section 6. The refrigerant then flows along
the above-described two routes, and flows out from the refrigerant
outlet 29 of the sixth section 28 toward the compressor. While
flowing through the heat exchange tubes 3 of the leeward tube row 4
and the heat exchange tubes 3 of the windward tube row 5, the
refrigerant exchanges heat with air passing through the air-passing
gaps 11 (see the arrow X in FIGS. 1 and 4). As a result, the air is
cooled, and the refrigerant flows out in gaseous phase.
[0039] When the temperature of the corrugated fins 12 disposed in
the third tube group 16 of the evaporator 1 detected by the
temperature sensor 2 becomes equal to or lower than the off-side
target temperature, the clutch means is brought into a disconnected
or disengaged state, whereby the compressor is stopped. When the
temperature of the corrugated fins 12 disposed in the third tube
group 16 of the evaporator 1 detected by the temperature sensor 2
elevates to the on-side target temperature higher than the off-side
target temperature by a predetermined temperature, the clutch means
is brought into a connected or engaged state, whereby operation of
the compressor is resumed.
[0040] The refrigerant having flowed into the evaporator 1 through
the refrigerant inlet 24 thereof flows over substantially the same
period of time and the same distance before reaching the third tube
group 16, which is the farthest tube group of the leeward tube row
4, and before reaching the fourth tube group 17, which is the
farthest tube group of the windward tube row 5. Therefore, when the
compressor is switched from the off state to the on state, the heat
exchange tubes 3 and the corrugated fins 12 disposed in the two
tube groups 16 and 17 of the evaporator 1 are cooled uniformly. As
a result, when the compressor is turned on, the temperature of the
corrugated fins 12 disposed in the third tube group 16 of the
evaporator 1 becomes equal to or lower than the off-side target
temperature within a relatively short period of time. Accordingly,
it is possible to prevent occurrence of a problem in that the
temperatures of the heat exchange tubes 3 and the corrugated fins
12 disposed in the tube groups of the evaporator 1 other than the
third tube group 16 and the fourth tube group 17 (i.e., the first
tube group 14, the second tube group 15, and the fifth tube group
18) decrease, and condensed water freezes on the surfaces of the
heat exchange tubes 3 and the corrugated fins 12. As a result,
production of an offensive smell called freezing odor, which is
produced as a result of freezing of condensed water, can be
restrained.
[0041] Also, when the compressor is switched from the off state to
the on state, the temperature of a portion of the evaporator 1
where the first tube group 14 of the leeward tube row 4 closest to
the refrigerant inlet 24 is present is apt to decrease sharply.
However, the decrease in the temperature of the portion of the
evaporator 1 where the first tube group 14 is present, which
decrease occurs when the compressor is switched from the off state
to the on state, is mitigated for the following reason. When the
compressor is off, due to presence of a super heat region in the
fifth tube group 18 of the windward tube row 5 closest to the
refrigerant outlet 29, the temperature of a portion of the
evaporator 1 where the fifth tube group 18 is present becomes
considerably high. This high temperature mitigates the
above-mentioned decrease in the temperature of the portion of the
evaporator 1 where the first tube group 14 is present. Accordingly,
when the compressor is on, the decrease in the temperature of the
portion of the evaporator 1 where the first tube group 14 of he
leeward tube row 4 is present is restrained, whereby freezing of
condensed water is restrained.
[0042] In the above-described embodiment, three tube groups are
provided in the leeward tube row 4, and two tube groups are
provided in the windward tube row 5. However, the present invention
is not limited thereto. Also, depending on the number of tube
groups of the two tube rows 4 and 5, there may be employed a
structure in which the refrigerant inlet is provided at the leeward
lower header section, and the refrigerant outlet is provided at the
windward lower header section.
[0043] Notably, the present invention can be applied to a so-called
laminated-type evaporator in which a plurality of flat hollow
bodies each composed of a pair of dish-shaped plates which faces
each other and are brazed together along the circumferential edges
thereof are disposed in parallel. Each flat hollow body has two
heat exchange tubes juxtaposed in the air-passing direction and
extending in the vertical direction, and upper and lower header
forming portions communicating with the upper and lower ends of the
two heat exchange tubes. All the flat hollow bodies are brazed
together in such a manner that the upper header forming portions of
all the flat hollow bodies communicate with one another, and the
lower header forming portions of all the flat hollow bodies
communicate with one another. Thus, two tube rows each composed of
a plurality of heat exchange tubes extending in the vertical
direction and disposed at predetermined intervals in a direction
orthogonal to the air-passing direction are juxtaposed in the
air-passing direction, and the upper and lower header sections on
the leeward and windward sides with which the upper and lower ends
of the leeward and windward tube rows communicate are provided by
the header forming portions of all the flat hollow bodies.
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