U.S. patent application number 13/388324 was filed with the patent office on 2012-09-06 for air-conditioning system for a vehicle.
This patent application is currently assigned to Hitachi, Ltd.. Invention is credited to Yuto Imanishi, Tadashi Osaka, Itsuro Sawada, Sachio Sekiya.
Application Number | 20120222446 13/388324 |
Document ID | / |
Family ID | 44059466 |
Filed Date | 2012-09-06 |
United States Patent
Application |
20120222446 |
Kind Code |
A1 |
Sekiya; Sachio ; et
al. |
September 6, 2012 |
Air-Conditioning System for a Vehicle
Abstract
An air-conditioning system for a vehicle includes an
air-conditioning apparatus having a compressor 1 that compresses a
first refrigerant 40 and a first heat exchanger 2 that exchanges
heat between the first refrigerant 40 and external air and
performing temperature regulation; and an equipment cooling
apparatus that circulates a second refrigerant 41B between
equipment 53, 54, 55 for electrically driving the vehicle and a
second heat exchanger 7B to release heat absorbed from the
equipment 53, 54, 55 to air in the vehicle interior in the heat
exchanger 7B. The system further includes a heat-radiation
suppressing structure 60 that suppresses heat dissipation from the
equipment 53, 54, 55 to surrounding environment.
Inventors: |
Sekiya; Sachio;
(Hitachinaka-shi, JP) ; Osaka; Tadashi;
(Kashiwa-shi, JP) ; Sawada; Itsuro;
(Hitachinaka-shi, JP) ; Imanishi; Yuto;
(Hitachinaka-shi, JP) |
Assignee: |
Hitachi, Ltd.
Chiyoda-ku, Tokyo
JP
|
Family ID: |
44059466 |
Appl. No.: |
13/388324 |
Filed: |
August 25, 2010 |
PCT Filed: |
August 25, 2010 |
PCT NO: |
PCT/JP2010/064389 |
371 Date: |
May 11, 2012 |
Current U.S.
Class: |
62/498 |
Current CPC
Class: |
B60H 1/00385 20130101;
Y02T 10/7291 20130101; B60L 58/26 20190201; B60K 11/04 20130101;
Y02T 10/705 20130101; Y02T 10/7241 20130101; B60H 1/143 20130101;
B60L 3/0061 20130101; B60L 2210/40 20130101; B60L 1/003 20130101;
B60L 2200/26 20130101; Y02T 10/70 20130101; B60L 2240/36 20130101;
B60K 11/08 20130101; Y02T 10/64 20130101; B60L 3/003 20130101; B60L
58/27 20190201; Y02T 10/7005 20130101; B60H 2001/00307 20130101;
B60L 50/51 20190201; B60L 2240/425 20130101; B60L 2240/545
20130101; Y02T 10/642 20130101; B60L 50/52 20190201; B60L 2240/34
20130101; B60L 2240/525 20130101; Y02T 10/72 20130101; Y02T 90/16
20130101; B60L 2240/662 20130101; B60L 2200/40 20130101 |
Class at
Publication: |
62/498 |
International
Class: |
F25B 1/00 20060101
F25B001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 18, 2009 |
JP |
2009-262529 |
Claims
1. An air-conditioning system for a vehicle comprising: an
air-conditioning apparatus having a compressor that compresses a
first refrigerant and a first heat exchanger that exchanges heat
between the first refrigerant and external air and performing
temperature regulation of air in a vehicle interior of the vehicle;
an equipment cooling apparatus that circulates a second refrigerant
between equipment for electrically driving the vehicle and a second
heat exchanger to release heat absorbed from the equipment to the
air in the vehicle interior in the second heat exchanger, wherein
the air-conditioning system further comprises a heat-radiation
suppressing structure that suppresses heat dissipation from the
equipment to surrounding environment.
2. An air-conditioning system for a vehicle according to claim 1,
wherein the heat-radiation suppressing structure comprises an heat
insulating material that covers the equipment.
3. An air-conditioning system for a vehicle according to claim 1,
wherein the heat-radiation suppressing structure comprises a
shielding member that is provided between the first heat exchanger
and the equipment and shields the equipment from external air that
has passed through the first heat exchanger.
4. An air-conditioning system for a vehicle according to claim 3,
wherein the shielding member comprises a duct that accommodates
therein the first heat exchanger, the duct including a first
channel for guiding external air that has passed through the first
heat exchanger to the equipment, a second channel for discharging
the external air that has passed through the first heat exchanger
to outside the vehicle, and a wind distributing unit that switches
between the first and second channels to distribute the external
air that has passed through the first heat exchanger.
5. An air-conditioning system for a vehicle according to claim 1,
wherein the equipment for driving the vehicle comprises a plurality
of pieces of equipment, and the heat-radiation suppressing
structure has a layout of the plurality of pieces of the equipment
such that a piece of equipment among the plurality of pieces of the
equipment having a larger amount of heat generation is arranged at
a position further downstream in a flow of the second refrigerant,
and a piece of equipment having the largest amount of heat
generation among the plurality of pieces of the equipment is
provided close to the second heat exchanger.
6. An air-conditioning system for a vehicle according to any claim
1, further comprising a third heat exchanger that exchanges heat
between the first refrigerant and the second refrigerant.
7. An air-conditioning system for a vehicle according to claim 2,
further comprising a third heat exchanger that exchanges heat
between the first refrigerant and the second refrigerant.
8. An air-conditioning system for a vehicle according to claim 3,
further comprising a third heat exchanger that exchanges heat
between the first refrigerant and the second refrigerant.
9. An air-conditioning system for a vehicle according to claim 4,
further comprising a third heat exchanger that exchanges heat
between the first refrigerant and the second refrigerant.
10. An air-conditioning system for a vehicle according to claim 5,
further comprising a third heat exchanger that exchanges heat
between the first refrigerant and the second refrigerant.
Description
TECHNICAL FIELD
[0001] The present invention relates to an air-conditioning system
for a vehicle.
BACKGROUND ART
[0002] In the field of hybrid vehicles, there is known a system
that uses, for air-conditioning, heat released from an
heat-generating body such as a motor or an inverter installed in a
vehicle (see Patent Literature 1). When air-heating of a vehicle
interior is performed, cooling water warmed by the heat-generating
body is made to flow into a heat exchanger for air-conditioning of
the vehicle interior so that it can serve as a subsidiary
air-heating heat exchanger.
CITATION LIST
Patent Literature
[0003] [Patent Literature 1] Japanese Patent No. 4285292
SUMMARY OF INVENTION
Technical Problem
[0004] However, the conventional heat-generating body such as a
motor or an inverter is covered with a casing made of a metal and
the generated heat is released to external air. As a result, there
has been a problem that the heat of the heat-generating body is
released wastefully and has not been efficiently used for
air-heating of the vehicle interior.
Solution to Problem
[0005] According to a first aspect of the present invention, an
air-conditioning system for a vehicle comprises an air-conditioning
apparatus having a compressor that compresses a first refrigerant
and a first heat exchanger that exchanges heat between the first
refrigerant and external air and performing temperature regulation
of air in a vehicle interior of the vehicle; an equipment cooling
apparatus that circulates a second refrigerant between equipment
for electrically driving the vehicle and a second heat exchanger to
release heat absorbed from the equipment to the air in the vehicle
interior in the second heat exchanger, wherein the air-conditioning
system further comprises a heat-radiation suppressing structure
that suppresses heat dissipation from the equipment to surrounding
environment.
[0006] According to a second aspect of the present invention, in an
air-conditioning system for a vehicle according to the 1st aspect,
it is preferred that the heat-radiation suppressing structure
comprises an heat insulating member that covers the equipment as
the heat-release preventing structure.
[0007] According to a third aspect of the present invention, in an
air-conditioning system for a vehicle according to the 1st aspect,
it is preferred that the heat-radiation suppressing structure
comprises a shielding member that is provided between the first
heat exchanger and the equipment and shields the equipment from
external air that has passed through the first heat exchanger.
[0008] According to a fourth aspect of the present invention, in an
air-conditioning system for a vehicle according to the 3rd aspect,
it is preferred that the shielding member comprises a duct that
accommodates therein the first heat exchanger, the duct including a
first channel for guiding external air that has passed through the
first heat exchanger to the equipment, a second channel for
discharging the external air that has passed through the first heat
exchanger to outside the vehicle, and a wind distributing unit that
switches between the first and second channels to distribute the
external air that has passed through the first heat exchanger.
[0009] According to a fifth aspect of the present invention, in an
air-conditioning system for a vehicle according to the 1st aspect,
it is preferred that the equipment for driving the vehicle
comprises a plurality of pieces of equipment as the vehicle for
driving the vehicle and the heat-radiation suppressing structure
has a layout of the plurality of pieces of the equipment such that
a piece of equipment among the plurality of pieces of the equipment
having a larger amount of heat generation is arranged at a position
further down stream in a flow of the second refrigerant, and a
piece of equipment having the largest amount of heat generation
among the plurality of pieces of the equipment is provided close to
the second heat exchanger.
[0010] According to a sixth aspect of the present invention, in an
air-conditioning system for a vehicle according to any one of 1st
through 5th aspects, it is preferred that the comprises a third
heat exchanger that exchanges heat between the first refrigerant
and the second refrigerant.
Advantageous Effect of the Invention
[0011] According to the present invention, the heat radiation from
equipment to surrounding environment is suppressed and the heat
absorbed from the equipment can be released to the air in the
vehicle interior efficiently.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic diagram showing an air-conditioning
system for a vehicle according to the present invention;
[0013] FIG. 2 is a diagram illustrating operation of the system
during air-cooling operation;
[0014] FIG. 3 is a diagram illustrating operation of the system
during defrosting operation;
[0015] FIG. 4 is a diagram showing a first example of a
heat-release suppressing structure;
[0016] FIG. 5 is a diagram showing a second example of a
heat-release suppressing structure;
[0017] FIG. 6 is a diagram showing a third example of a
heat-release suppressing structure; and
[0018] FIG. 7 is a diagram showing a fourth example of heat-release
suppressing structure.
DESCRIPTION OF EMBODIMENTS
[0019] Hereafter, an embodiment is explained, in which the
air-conditioning system for a vehicle according to the present
invention is applied to an electric vehicle. Note that the present
invention is not limited to electric vehicles but also is
applicable to hybrid vehicles, and to electromotor vehicles of
electric railways, construction vehicles and the like. According to
the above-mentioned embodiment, explanation is made with reference
to an example of an alternate current motor driven by an inverter.
However, the present invention is not limited to the alternate
current motor but can be applied to all types of rotating machines
(motor generators) such as a direct current motor that can be
driven by a converter, such as a thyristor Leonard device or a
pulse motor that can be driven with chopper power source.
[0020] FIG. 1 is a diagram showing schematic construction of the
air-conditioning system for a vehicle according to the present
invention. The air-conditioning system for a vehicle shown in FIG.
1 includes a refrigeration cycle circuit 90 in which a refrigerant
40 flows, an air-conditioning circuit 91A having an interior heat
exchanger 7A connected to the refrigeration cycle circuit 90 with
an air-conditioning cooling medium 41A, and an equipment cooling
circuit 91B having an interior heat exchanger 7B, the
heat-generating body 9, and the refrigeration cycle circuit 90 with
an equipment cooling medium 41B.
[0021] In the refrigeration cycle circuit 90, a compressor 1 that
compresses the refrigerant 40, an exterior heat exchanger 2 that
exchanges heat between the refrigerant 40 and external air, a
liquid piping 12, an air-conditioning heat exchanger 4A that
exchanges heat with the air-conditioning cooling medium 41A in the
air-conditioning circuit 91A are connected in a circulating manner.
A four-way valve 20 is provided between an intake piping 11 and a
discharge piping 10. By switching the four-way valve 20, either one
of the intake piping 11 and the discharge piping 10 can be
connected to the exterior heat exchanger 2 and the other of the
intake pipe 11 and the discharge pipe 10 can be connected to the
air-conditioning heat exchanger 4A. FIG. 1 shows the air-heating
operation, in which the four-way valve 20 is switched to connect
the discharge piping 10 to the air-conditioning heat exchanger 4A
and the intake piping 11 to the exterior heat exchanger 2.
[0022] The cooling heat exchanger 4B exchanges heat between the
refrigerant 40 of the refrigeration cycle circuit 90 and the
equipment cooling medium 41B. The cooling heat exchanger 4B is
connected on one end thereof to the liquid piping 12 and on the
other end thereof switchably connected to either one of the
discharge pipe 10 and the intake pipe llthrough a three-way valve
21. The liquid piping 12 is provided with a receiver 24. Expansion
valves 23, 22A, and 22B that serve as flow rate control means are
provided between the receiver 24 and the exterior heat exchanger 2,
between the air-conditioning heat exchanger 4A and the receiver 24,
and between the cooling heat exchanger 4B and the receiver 24,
respectively, on the liquid piping 12. The exterior heat exchanger
2 is provided with an exterior fan 3 for blowing external air.
[0023] To the air-conditioning circuit 91A are connected the
interior heat exchanger 7A that exchanges heat with air blown out
into the vehicle interior by an interior fan 8, a circulation pump
5A that circulates the air-conditioning cooling medium 41A, and the
air-conditioning heat exchanger 4A in order in a circulating
manner.
[0024] To the equipment cooling circuit 91B are connected an
interior heat exchanger 7B that exchanges heat with air flown out
from the interior heat exchanger 7A, a reservoir tank 6, a
circulation pump 5B that circulates the equipment cooling medium
41B, the cooling heat exchanger 4B, an heat-generating body 9 such
as a motor, an inverter, a battery or the like in order in a
circulating manner. The equipment cooling circuit 91B is provided
with a bypass circuit 30 that bypasses both ends of the interior
heat exchanger 7B. The bypass circuit 30 is provided with a two-way
valve 25 and a main circuit 31 that passes through the interior
heat exchanger 7B is provided with a two-way valve 26. By switching
actions of the two-way valves 25, 26, it is possible to arbitrarily
configure the flow path of the equipment cooling medium 41B.
[0025] (Air-Heating Operation)
[0026] According to the present embodiment, heat emission from the
heat-generating body 9 is used for heating the vehicle interior
during air-heating operation. In this case, if the air-heating load
is low, air-heating is performed by using the heat emission form
the heat-generating body 9 without using the refrigeration cycle
circuit 90. If the heat emission from the heat-generating body 9
does not cover the air-heating load, the refrigeration cycle
circuit 90 is used in combination.
[0027] When the air-heating is performed by using only the heat
emission from the heat-generating body 9, the circulation pump 5B
and the interior fan 8 are activated and the two-way valve 26 is
opened to flow the equipment cooling medium 41B into the interior
heat exchanger 7B. Since the equipment cooling medium 41B is heated
by the heat-generating body 9, the equipment cooling medium 41B
will be cooled by releasing heat to the air blown out into the
vehicle interior in the interior heat exchanger 7B and thus the air
blown out into the vehicle interior is heated.
[0028] On the other hand, when the heat emission from the
heat-generating body 9 alone does not cover the air-heating load,
the refrigeration cycle circuit 90 is used in combination. In this
case, the four-way valve 20 is switched as indicated by a solid
line to connect the discharge piping 10 of the compressor 1 with
the air-conditioning heat exchanger 4A and the intake piping 11
with the exterior heat exchanger 2. That is, a cycling is formed in
which the air-conditioning heat exchanger 41A serves as a condenser
and the exterior heat exchanger serves as an evaporator.
[0029] The refrigerant 40 compressed by the compressor 1 is
condensed and liquefied by releasing heat to the air-conditioning
cooling medium 41A in the air-conditioning heat exchanger 4A.
Thereafter, it is depressurized with an expansion valve 23 and
exchanges heat with the external air in the exterior heat exchanger
2 to be evaporated, gasified and is returned to the compressor 1.
Note that the expansion valve 22A is fully opened and the expansion
valve 22B is fully closed and the cooling heat exchanger 4B is not
used.
[0030] By activating the circulation pump 5A, the air-conditioning
cooling medium 41A, which has gained condensation heat of the
refrigerant 40 in the air-conditioning heat exchanger 4A and has an
elevated temperature, is lead to flow into the interior heat
exchanger 7A and releases heat to the air blown out there into the
vehicle interior. The air heated by the interior heat exchanger 7A
further gains heat from the equipment cooling medium 41B heated by
the heat-generating body 9, in the interior heat exchanger 7B
disposed on the side downstream of the flow of air, its temperature
being further elevated and then blown out into the vehicle interior
space.
[0031] According to this configuration, the air blown out into the
vehicle interior, after it is heated by the refrigeration cycle
circuit 90, is further heated by the heat emission from the
heat-generating body 9. As a result, the temperature of the air
blown out from the interior heat exchanger 7A is maintained at a
temperature that is lower than the temperature of the air blown out
from the interior heat exchanger 7B. That is, by using the heat
emission from the heat-generating body 9 for air-heating, an
air-conditioning apparatus with reduced energy consumption can be
constructed.
[0032] (Defrosting Operation)
[0033] When the operation in which the exterior heat exchanger 2 is
used as an evaporator is continued, it may sometimes happen that
frost grows on a surface of the heat exchanger, and hence it
becomes necessary to perform defrosting operation for melting the
frost. During the defrosting operation, the four-way valve 20 and
the three-way valve 21 are switched as indicated by solid lines in
FIG. 3. Then, the expansion valve 22A is fully closed to form a
cycling in which the exterior heat exchanger 2 serves as a
condenser and the cooling heat exchanger 4B serves as an
evaporator. On the other hand, the two-way valve 26 is closed to
cut off the flow to the main circuit 31 and allows the equipment
cooling medium 41B to flow into the bypass circuit 30.
[0034] Use of the air-conditioning heat exchanger 4A as an
evaporator makes it easy to decrease the temperature of the air
blown out into the vehicle interior. Accordingly, the heat emission
from the heat-generating body 9 is used as a heat source, so that a
reduction in temperature of the vehicle interior can be prevented.
When the air blown out into the vehicle interior is used as a heat
source, the amount of heat may not be sufficient, and therefore
defrosting may take a longer time. However, since the equipment
cooling medium 41B, which is maintained at a high temperature due
to the heat-generating body 9 being connected with the system, can
be used as a heat source for defrosting, advantageously, the heat
source for defrosting can be secured so that the time for
defrosting can be shortened. During the defrosting operation, a
decrease in temperature can be prevented by controlling the amount
of wind from the interior fan 8 or by stopping the interior fan
8.
[0035] (Air-Cooling Operation)
[0036] FIG. 2 is a diagram illustrating the action of the system at
the time of air-cooling operation. Here, the term "air-cooling
operation" means an operation mode in which both the
air-conditioning circuit 91A and the equipment cooling circuit 91B
are enabled to perform air-cooling. In the air-cooling operation,
the exterior heat exchanger 2 is used as a condenser, and the
air-conditioning heat exchanger 4A and the cooling heat exchanger
4B are used as evaporators, with the four-way valve 20 being
brought into a condition indicated by a solid line.
[0037] The refrigerant 40 compressed by the compressor 1 releases
heat in the exterior heat exchanger 2 to be liquefied and then
branched into a portion of the refrigerant that flows into the
air-conditioning heat exchanger 4A and a portion of the refrigerant
that flows into the cooling heat exchanger 4B through the receiver
24. The portion of the refrigerant that flows into the
air-conditioning heat exchanger 4A is depressurized by a
depressurizing means 22A to become low in temperature and pressure
and evaporates when it absorbs heat from the air-conditioning
cooling medium 41A of the air-conditioning circuit 91A in the
air-conditioning heat exchanger 4A, and passes through the four-way
valve 20 and returns to the compressor 1. On the other hand, the
portion of the refrigerant that flows into the cooling heat
exchanger 4B is depressurized in a depressurizing means 22B to
become low in temperature and pressure and absorbs heat from the
equipment cooling medium 41B of the equipment cooling circuit 91B
in the cooling heat exchanger 4B, passes through the three-way
valve 21 and returns to the compressor 1.
[0038] When the circulation pump 5A provided in the
air-conditioning circuit 91A is driven, the air-conditioning
cooling medium 41A cooled by the air-conditioning heat exchanger 4A
is supplied to the interior heat exchanger 7A. Then, when the
interior fan 8 is driven, air cooled as a result of heat exchange
in the interior heat exchanger 7A is blown out into the vehicle
interior. When the circulation pump 5B provided in the equipment
cooling circuit 91B is driven, the equipment cooling medium 41B
heated by the heat-generating body 9 is cooled as a result of heat
exchange in the cooling heat exchanger 4B. Note that during the
air-cooling operation, the two-way valve 26 in the main circuit 31
is closed, so that the equipment cooling medium 41B that is at a
high temperature flows through the bypass circuit 30. Note that
during the air-cooling operation, the two-way valve 26 in the main
circuit 31 is closed, so that the equipment cooling medium 41B that
is at a high temperature flows through the bypass circuit 30.
[0039] In this manner, both the air-conditioning heat exchanger 4A
and the cooling heat exchanger 4B can be used as evaporators, so
that cooling of the vehicle interior and cooling of the
heat-generating body 9 can be implemented simultaneously.
Furthermore, since the air-conditioning heat exchanger 4A and the
cooling heat exchanger 4B are connected in parallel to the intake
piping 11 of the compressor 1 and the expansion valves 22A, 22B are
provided to both the refrigerant circuits, the flow rates of the
portions of the refrigerants that flow into the air-conditioning
heat exchanger 4A and the cooling heat exchanger 4B, respectively,
can be freely varied. As a result, the temperatures of the
equipment cooling medium 41B and the air-conditioning cooling
medium 41A can be controlled to any desired temperatures,
respectively. Therefore, even when the temperature of the
air-cooling medium 41A is sufficiently decreased in order to
perform air-cooling, the temperature of the equipment cooling
medium 41B in case that the heat-generating body 9 is connected can
be maintained high by controlling the flow rate of the portion of
the refrigerant that flows into the cooling heat exchanger 4B.
[0040] In order to efficiently use the heat emission from the
heat-generating body 9 in the equipment cooling circuit 91B shown
in FIG. 1, it is necessary as much as possible to reduce heat that
dissipates from the heat-generating body 9 that is at a high
temperature to the ambient and heat that dissipates from the piping
for refrigerant flowing from the heat-generating body 9 to the
interior heat exchanger 7B to the ambient. Accordingly, in the
following, a construction for preventing heat-release form the
heat-generating body 9 and the pipe for the refrigerant to the
ambient are described.
[0041] [First Heat-Release Preventing Structure]
[0042] FIG. 4 is a diagram that shows an example of the
heat-radiation suppressing structure, indicating the case in which
it is applied to an electric vehicle. FIG. 4 schematically shows
the arrangement of each equipment when a motor 53 for driving is
mounted in the front portion of a vehicle 50. A space 51A in the
vehicle 50 is a space that corresponds to an engine room in a
conventional engine-driven vehicle. Hereafter, the space 51A is
called a motor reception room and the space 51B is called a vehicle
interior.
[0043] In each equipment shown in FIG. 1, equipment excluding the
interior heat exchangers 7A, 7B and interior fan 8 is arranged in
the motor reception room 51A shown in FIG. 2. FIG. 4 shows, as main
equipments, a motor 53, an inverter 54 for controlling driving of
the motor 53, a cooling unit 52, the exterior heat exchanger 2, and
the exterior fan 3. The cooling unit 52 includes the equipment
provided in the refrigeration cycle circuit 90 shown in FIG. 1 (the
compressor 1, the heat exchangers 4A, 4B, the valves 20, 21 and so
on) as well as the circulation pumps 5A, 5B and so on. The interior
heat exchangers 7A, 7B and the interior fan 8 shown in FIG. 1 are
arranged in the vehicle interior 51B. Note that in FIG. 4, the
interior heat exchanger 7A and the interior fan 8 are omitted. In
FIG. 4, the motor 53 and the inverter 54 correspond to the
heat-generating body 9 in FIG. 1.
[0044] As shown in FIG. 4, the exterior heat exchanger 2 and the
exterior fan 3 are arranged in the front most portions (on the left
hand side in the FIG. 4) so that heat exchange with the external
air can be efficiently performed. The cooling unit 52, the motor
53, the inverter 54 and so on is arranged to the rear of the
exterior heat exchanger 2 and the exterior fan 3. As a result, a
wind 61 caused by running of the vehicle and the exterior fan 3
passes through the exterior heat exchanger 2 and then is blown out
to the cooling unit 52, the motor 53, the inverter 54, the piping
55 and so on arranged to the rear of the exterior heat exchanger
2.
[0045] Generally, the motor 53 and the inverter 54 is configured to
allow release of heat from the casing made of a metal to ambient
air in order to prevent temperature elevation. As a result, even
when the cooling structure with the cooling medium 41B is employed,
heat is radiated from the casing to the ambient air that directly
comes in contact with the casing. Heat dissipates wastefully also
from the piping 55, in which the equipment cooling medium 41B at a
high temperature flows, to the ambient air by heat radiation.
[0046] As a result, the amount of heat released from the motor 53,
the inverter 54 and the piping 55 to the ambient air increases,
which hinders efficient utilization of the heat generated by the
motor 53 and the inverter 54, which are heat-generating bodies, for
air-heating of the vehicle interior. In particular, since the
exterior heat exchanger 2 serves as an evaporator during the
air-heating operation, external air is cooled when it passes
through the exterior heat exchanger, so that the temperature of the
external air becomes lower than the temperature of the external air
at the beginning. Thus, wind of lower temperature than the external
air is blown out to the motor 53, the inverter 54 and the piping
55.
[0047] Accordingly, in the first heat-radiation suppressing
structure, a wall 60 is arranged between the cooling unit 52 and
the exterior fan 8 as shown in FIG. 4 to provide a structure that
prevents the wind 61 that has passed through the exterior heat
exchanger 2 from being blown out to the cooling unit 52, the motor
53, the inverter 54, and the pipe 55. The wind 61 that has passed
through the exterior heat exchanger 2 flows along the wall 60
obliquely in the direction of lower right, and discharged outside
the vehicle from the bottom surface portion of the motor reception
room 51A. As a result, the amount of heat radiated from the motor
53, the inverter 54 and the pipe 55 is decreased, thus making it
possible to increase efficiency of utilization of the heat
emission, and enableing a reduction in power consumption by the
refrigeration cycle for air-heating.
[0048] [Second Heat-Radiation Suppressing Structure]
[0049] FIG. 5 is a diagram showing a second example of the
heat-radiation suppressing structure. In the case of the first
heat-radiation suppressing structure mentioned above, the flow of
the wind 61 that has passed through the exterior heat exchanger 2
is varied by the wall 60, so that the wind 61 is prevented from
being blown out to the motor 53, the inverter 54 and the piping 55,
which are heat-generating bodies. On the other hand, in the case of
the heat-radiation suppressing structure shown in FIG. 5, a duct 70
that accommodates the exterior heat exchanger 2 and the exterior
fan 3 is provided in the motor reception space 51A in order to
prevent the wind 61 from being blown out to the motor 53, the
inverter 54 and the pipe 55, which are heat-generating bodies.
[0050] The duct 70 includes a cooling duct 70a and a discharging
duct 70b. The cooling duct 70a guides the wind that has passed
through the exterior heat exchanger 2 to the motor 53, the inverter
54, and batteries for driving (not shown). The discharging duct 70b
discharges the wind that has passed through the exterior heat
exchanger 2 to outside the vehicle. The ducts 70a, 70b are provided
with dampers 71, 72, respectively, which are gates for adjusting
the amount of wind. In the configuration shown in FIG. 5, a
multi-blade fan (Sirocco fan) instead of a propeller fan is used as
the exterior fan 3. By using a cylindrical multi-blade fan, the
depth size (size in the front-back direction of the vehicle) of the
duct 70 can be minimized.
[0051] During an air-heating operation, the damper 71 of the
cooling duct 70a is closed whereas the damper 72 of the discharging
duct 70b is opened. As a result, the wind 61 that has passed
through the exterior heat exchanger 2 is discharged through the
discharging duct 70b to outside the vehicle, so that it is not
blown out to the motor 53, the inverter 54 and the pipe 55.
Therefore, the heat radiation from the motor 53 and the inverter 54
is suppressed and the heat emission therefrom becomes to be used
efficiently.
[0052] In the case where the temperature of external air is high as
in summer seasons, further cooling becomes necessary in order to
prevent the heat-generating body from gaining a too high
temperature. In such a case, the damper 72 is closed and the damper
71 is opened as shown in FIG. 5 to allow the wind from the exterior
fan 3 to be blown out to the heat-generating body to increase heat
dissipation therefrom. As mentioned above, during a air-cooling
operation, the equipment cooling medium 41B for cooling the
heat-generating body is cooled by the refrigerant 40 in the
refrigeration cycle circuit 90 in the cooling heat exchanger 4B. As
a result, by cooling the heat-generating body by the wind from the
exterior fan 3 as shown in FIG. 5, the cooling load for the
refrigeration cycle circuit 90 can be controlled, thus enabling
decrease of power consumption.
[0053] If the wind 61 is blown onto the exterior heat exchanger 2
during the above-mentioned defrosting operation, the temperature of
the exterior heat exchanger 2 becomes hard to be increased, so that
it becomes difficult to melt the frost. Then, during the defrosting
operation, the exterior fan 3 is stopped and the dampers 71, 72 are
closed in order to make it difficult for the wind 61 to flow
through the exterior heat exchanger 2.
[0054] [Third Heat-Radiation Suppressing Structure]
[0055] FIG. 6 is a diagram showing an example of a third
heat-radiation suppressing structure. In the case of the first and
second heat-radiation suppressing structures, the wind 61 that has
passed through the exterior heat exchanger 2 is prevented from
being blown out to the motor 53, the inverter 54, and the piping
55, which are heat-generating bodies, for decreasing the amount of
heat dissipated therefrom by providing the wall 60 or the duct
70.
[0056] The motor 53 and the inverter 54 have a structure that
allows heat to be radiated via their casings made of metal to the
ambient air as mentioned above. As a result, even when a structure
is adopted with which the wind 61 that has passed through the
exterior heat exchanger 2 is not blown out to the motor 53 and the
inverter 54, heat is dissipated to the ambient air. Accordingly, in
the third heat-radiation suppressing structure, the motor 53 and
the inverter 54, which are heat-generating bodies and the piping 55
in which the equipment cooling medium 41B of high temperature flows
are accommodated in the casing 56 for suppressing heat radiation so
as to decrease heat dissipated from the heat-generating bodies to
the air in the motor reception room 51A.
[0057] By providing the casing 56, it is prevented that the motor
53, the inverter 54 and the pipe 55 are exposed to the wind 61 that
has passed through the exterior heat exchanger 2, so that similar
effect to that given by the wall 61 as shown in FIG. 2 is obtained.
Furthermore, since the air surrounding the motor 53, the inverter
54 and the piping 55 is separated from the air in the motor
reception room 51A by the casing 56, heat transfer from the air in
the casing 56 to the air in the motor reception room 51A is done
only via thermal conduction through the casing 56. As a result, the
heat radiation from the motor 53, the inverter 54 and the piping 55
may be decreased more than the case where they are arranged as
exposed in the motor reception room 51A as shown in FIG. 2.
[0058] Though the material that constitutes the casing 56 is
preferably a heat insulating material, it may be a metal. The
casing 56 may be of a double-walled structure, with which a
sufficient heat insulation effect can be obtained even when the
casing 56 is made of metallic material.
[0059] Though all of the motor 53, the inverter 54 and the pipe 55
are accommodated in one casing 56 in FIG. 6, each pieces of the
equipment may be enclosed by a casing made of an heat insulating
material or the surface of each pieces of the equipment may be
covered with an heat insulating material. Instead of using a casing
structure such as the casing 56, the surface of each pieces of the
equipment may be coated with an heat insulating material (for
example, a resin) to form a layer of the heat insulting material on
the surface of the motor 53, the inverter 54 and the pipe 55.
Furthermore, such an heat insulating structure and the
above-mentioned wall 60 may be used together.
[0060] [Fourth Heat-Radiation Suppressing Structure]
[0061] FIG. 7 is a diagram showing a fourth example of the
heat-radiation suppressing structure. In the fourth heat-radiation
suppressing structure, by appropriately modifying the layout of
each equipment provided in the equipment cooling circuit 91B shown
in FIG. 1, the length of the piping in which the equipment cooling
medium 41B having a relatively high temperature flows is made
smaller to suppress the heat radiation from the piping. Note that
according to the construction shown in FIG. 7, the duct 70 is
provided in order that the wind from the exterior fan is not blown
out to the motor 53. However, a construction which do not include
the duct 70 and the wall 60 may be used.
[0062] The arrangement of each equipment as shown in FIG. 7 is
determined based on the guiding principle indicated below.
(1) Along the flow of equipment cooling medium 41B, a circulation
pump 5B, a cooling heat exchanger 4B, an heat-generating body, and
an interior heat exchanger 7B are connected in order. (2) The piece
of the equipment that has an outlet of the equipment cooling medium
41B located at the highest position is arranged at the most
downstream side between the circulation pump 5B and the interior
heat exchanger 7B, i.e., near the interior heat exchanger 7B. (3)
The piece of the equipment that has the largest amount of heat
generation is arranged at the most downstream position between the
circulation pump 5B and the interior heat exchanger 7B. (4) The
circulation pump 5B is arranged to the front part of the vehicle
from the heat-generating body.
[0063] The guiding principle (1) is settled based on the following
reason. Taking into consideration the function of the reservoir
tank 6, it is preferred that the reservoir tank 6 is provided on
the intake side of the circulation pump 5B. Furthermore, the
reservoir tank 6 needs to be located at the highest position in the
equipment cooling circuit 91B. On the other hand, the circulation
pump 5B for circulating the equipment cooling medium 41B is
provided preferably at the lowest position. A communication hole 81
through which the piping to the interior heat exchanger 7B provided
in the vehicle interior 51B is arranged at a relatively high
position in the motor reception room 51A. Accordingly, by providing
the reservoir tank 6 on the downstream side of the interior heat
exchanger 7B, the reservoir tank 6 can be arranged at a high
position and the piping can be shorter.
[0064] For example, let us consider a case in which the reservoir
tank 6 is not arranged on the downstream side of the interior heat
exchanger 7B and the cooling heat exchanger 4B, the reservoir tank
6, and the circulation pump 5B are connected in order. In this
case, since it is preferred that the cooling heat exchanger 4B that
has a relatively large weight, the piping is arranged from the
cooling heat exchanger 4B at a lower position to once the reservoir
tank 6 that is at a higher position and then it is arranged again
to the circulation pump 5 that is at a lower position. As a result,
the piping length is increased to cause the heat radiation from the
piping to increase.
[0065] Regarding the guiding principle (2), the communication hole
81 related to the interior heat exchanger 7B is provided at a
relatively high position. Accordingly, by connecting the piece of
the equipment that has an outlet of refrigerant at a high position
on the most downstream side, that is, on the upstream side of the
interior heat exchanger 7B, the piping between the piece of the
equipment and the interior heat exchanger 7B can be shorter. In the
case of the present embodiment, the motor 53 having a large size is
connected on the upstream side of the interior heat exchanger 7B.
Since the equipment cooling medium 41B of a high temperature flows
through the piping on the upstream side of the interior heat
exchanger 7B, a reduction in the amount of heat dissipation can be
decreased by shorter piping.
[0066] The guiding principle (3) is based on the following reason.
The larger the amount of heat generation of the equipment is, the
higher the temperature of the equipment cooling medium 41B that
flows out of the equipment is. As a result, by arranging the piece
of the equipment that has the largest amount of heat generation at
the most downstream side, the length of the piping through which
the equipment cooling medium 41B that has the highest temperature
can be shorter. In the case such an arrangement is adopted, the
length of the piping on the upstream side of the piece of the
equipment concerned is increased. However, the temperature of the
refrigerant can be maintained at a relatively lower level on the
upstream side of the piece of the equipment concerned, so that the
total heat dissipation from the piping can be decreased.
[0067] Taking into consideration the guiding principle (4) in
addition to the guiding principle (3), the heat-generating bodies
are arranged in series between the circulation pump 5B placed at a
lower position and the interior heat exchanger 7B placed at a
higher position. That is, it is possible to avoid the arrangement
of the piping from going backward in the front-back direction of
the vehicle, so that the total length of the piping in which
equipment cooling medium 41B having a high temperature flows can be
shorter. When such an arrangement of the piping is employed, the
length of the piping from the reservoir tank 6 to the circulation
pump 5B becomes relatively large. However, because in this piping
flows the equipment cooling medium 41B that has released heat in
the interior heat exchanger 7B flows, the temperature of the
refrigerant is relatively low, causing less adverse effect of heat
loss.
[0068] The arrangement of each component in FIG. 7 is set up
according to the above-mentioned guiding principles (1) to (4) and
the piping connection is done from the reservoir tank 6 that is
arranged at the highest position near the through hole 81 to the
circulation pump 5B arranged on the side of the front portion of
the vehicle in the equipment cooling circuit 91B. On the downstream
side of the circulation pump 5B is connected the cooling heat
exchanger 4B. The cooling heat exchanger 4B is arranged at a low
position like the circulation pump 5B and a plurality of
heat-generating bodies are arranged in an ascending order regarding
heat generation amount between the cooling heat exchanger 4B and
the interior heat exchanger 7B located at a high position.
[0069] In the above-mentioned embodiment, the battery 80 for
driving, as an heat-generating body, is omitted. However, in the
example shown in FIG. 7, the battery 80 for driving is provided as
a heat-generating body in addition to the motor 53 and the inverter
54. A two-way valve V1 is provided between the battery 80 for
driving and the inverter 54, and a bypass circuit 82 provided with
a two-way valve V2 is arranged in parallel to the battery 80 for
driving. Usually, the two-way valve V1 is closed and at the same
time the two-way valve V2 is opened to flow the equipment cooling
medium 41B to bypass the battery 80 for driving. Since the
temperature of the battery 80 for driving increases during
charging, the two-way valve V1 is opened and at the same time the
two-way valve V2 is closed to cool the battery 80 for driving with
the equipment cooling medium 41B, whereby the heat is utilized for
air-heating of the vehicle interior. Of course, cooling is
performed even when it is not a time of charging, if it is expected
that the temperature of the battery will exceed allowable
temperature of the battery 80 for driving.
[0070] The battery 80 for driving shown in FIG. 7 operates most
efficiently when the temperature of battery is 50 to 60.degree. C.
On the other hand, when external air temperature is considerably
low such as in particular in winter seasons, a low temperature
state may continue for a while after the vehicle is started, so
that there may be a case that the maximum capacity of the battery
80 for driving cannot be attained. Accordingly, the equipment
cooling circuit 91B may be provided with a heater in order to heat
the equipment cooling medium 41B by the heater up to an optimal
temperature in case the temperature of the equipment cooling medium
41B is too low. In this case, it is simplest and most desirable to
provide a heater to the reservoir tank 6. By turning the heater on
to elevate quickly the temperature of the equipment cooling medium
41B to the optimal temperature, the capacity of the battery 80 for
driving can be fully exploited immediately after the starting up of
the vehicle.
[0071] As described above, the air-conditioning system for a
vehicle according to the present embodiment comprises the
refrigeration cycle circuit 90 that includes the compressor 1 for
compressing the refrigerant 40 and the exterior heat exchanger 2
for exchanging heat between the refrigerant 40 and external air and
that performs air-conditioning of air in the vehicle interior, the
air-conditioning circuit 91, and the equipment cooling circuit 91B
that circulates the equipment cooling medium 41B among the motor
53, an equipment for electrically driving the vehicle, the inverter
54 and the like, and the interior heat exchanger 7B, and that
releases heat absorbed from the equipment to the air in the vehicle
interior with the interior heat exchanger 7B. As a heat-radiation
suppressing means that suppresses heat dissipation from the
equipment to surrounding environment, the casing 56 made of an heat
insulating material covering the equipment is provided; the wall 60
or duct 70 is provided as a shielding member that shields the
equipment from the wind 61; or a layout of a plurality of pieces of
equipment (motor 53, inverter 54, and battery 80 for driving) as
shown in FIG. 7 is arranged such that a piece of equipment having a
larger amount of heat generation is placed at more downstream of
the flow of the equipment cooling medium 41B and a piece of
equipment having the largest amount of heat generation is placed in
the vicinity of the interior heat exchanger 7B.
[0072] By providing such a heat-radiation suppressing means, the
heat emission from the heat-generating body (motor 53, inverter 54,
battery 80 for driving) can be efficiently used for
air-conditioning of the vehicle interior.
[0073] The above-mentioned embodiments may be used alone or in any
combination. This is because the respective advantageous effects of
the embodiments can be exhibited alone or synergistically. So far
as the features of the present invention are not impaired, the
present invention is not limited to the above-mentioned
embodiments.
[0074] Although in the foregoing, various embodiments and
variations thereof have been explained, the present invention
should not be construed as being limited thereto. Other aspects
conceived within the technical concept of the present invention are
included in the scope of the present invention. Other aspects
conceived within the technical concept of the present invention are
included in the scope of the present invention.
[0075] The disclosure of the following priority application is
herein incorporated by reference: Japanese Patent Application No.
2009-262529 (filed Nov. 18, 2009).
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