U.S. patent application number 13/005130 was filed with the patent office on 2011-07-14 for vehicular air-conditioning system.
This patent application is currently assigned to HONDA MOTOR CO., LTD.. Invention is credited to Hidenori ESAKI, Satoshi KOBAYASHI, Daisuke YAMAOKA.
Application Number | 20110167849 13/005130 |
Document ID | / |
Family ID | 43511192 |
Filed Date | 2011-07-14 |
United States Patent
Application |
20110167849 |
Kind Code |
A1 |
KOBAYASHI; Satoshi ; et
al. |
July 14, 2011 |
VEHICULAR AIR-CONDITIONING SYSTEM
Abstract
A vehicular air-conditioning system has a heat pump circulation
passage for circulating a coolant with a compressor. To the heat
pump circulation passage, there are connected a condenser for
performing a heat exchange between a coolant and ambient air, an
expansion valve, a first evaporator, a heater, and a second
evaporator. The heat pump circulation passage includes a coolant
retrieval passage extending from a divider between the condenser
and the gas-liquid separator and connected to the compressor. A
second backflow check valve for preventing the coolant from flowing
from the compressor to the divider and a solenoid-operated valve
are connected to the coolant retrieval passage.
Inventors: |
KOBAYASHI; Satoshi;
(Utsunomiya-shi, JP) ; ESAKI; Hidenori;
(Utsunomiya-shi, JP) ; YAMAOKA; Daisuke;
(Utsunomiya-shi, JP) |
Assignee: |
HONDA MOTOR CO., LTD.
Tokyo
JP
|
Family ID: |
43511192 |
Appl. No.: |
13/005130 |
Filed: |
January 12, 2011 |
Current U.S.
Class: |
62/159 ;
62/238.6 |
Current CPC
Class: |
B60H 1/039 20190501;
B60H 2001/00949 20130101; B60H 1/00921 20130101; B60H 1/00914
20130101 |
Class at
Publication: |
62/159 ;
62/238.6 |
International
Class: |
F25B 29/00 20060101
F25B029/00; F25B 27/00 20060101 F25B027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 13, 2010 |
JP |
2010-005117 |
Claims
1. An air-conditioning system for use on a vehicle, comprising: a
heat pump circulation passage for circulating a coolant with a
compressor; a condenser disposed in the heat pump circulation
passage, for performing a heat exchange between the coolant and
ambient air; an expansion valve disposed in the heat pump
circulation passage, for depressurizing the coolant which is
delivered from the condenser; a first evaporator disposed in the
heat pump circulation passage, for performing a heat exchange
between the coolant which has passed through the expansion valve
and air-conditioning air; a heater disposed in the heat pump
circulation passage, for performing a heat exchange between the
coolant which is delivered from the compressor and the
air-conditioning air which has passed through the first evaporator;
a second evaporator disposed in a branch passage branched from the
heat pump circulation passage, for performing a heat exchange
between the coolant and a heating medium obtained from within or
outside the vehicle; and a gas-liquid separator and an auxiliary
condenser which are disposed downstream of the condenser and
connected between the condenser and the expansion valve; wherein
the heat pump circulation passage includes a coolant retrieval
passage extending from a divider between the condenser and the
gas-liquid separator and connected to the compressor.
2. The air-conditioning system according to claim 1, further
comprising backflow check means connected to the coolant retrieval
passage, for preventing the coolant from flowing from the
compressor to the divider.
3. The air-conditioning system according to claim 1, further
comprising an on-off valve connected to the coolant retrieval
passage; wherein the on-off valve is opened in a heating mode and
closed in a cooling mode.
4. The air-conditioning system according to claim 2, further
comprising an on-off valve connected to the coolant retrieval
passage; wherein the on-off valve is opened in a heating mode and
closed in a cooling mode.
5. The air-conditioning system according to claim 3, further
comprising a controller for switching between the heating mode and
the cooling mode and controlling opening and closing of the on-off
valve; wherein in the heating mode, the controller opens the on-off
valve and thereafter activates the compressor for a prescribed time
and then closes the on-off valve.
6. The air-conditioning system according to claim 4, further
comprising a controller for switching between the heating mode and
the cooling mode and controlling opening and closing of the on-off
valve; wherein in the heating mode, the controller opens the on-off
valve and thereafter activates the compressor for a prescribed time
and then closes the on-off valve.
7. The air-conditioning system according to claim 1, wherein the
heating medium which is supplied to the second evaporator for a
heat exchange with the coolant comprises a medium which is higher
in temperature than the coolant.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2010-005117 filed on
Jan. 13, 2010, of which the contents are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a heat-pump vehicular
air-conditioning system for use on a vehicle for air-conditioning
the passenger's cabin of the vehicle.
[0004] 2. Description of the Related Art
[0005] Various vehicular air-conditioning systems have been used
for use on various vehicles including engine vehicle powered by an
internal combustion engine, hybrid vehicles powered by an engine
and a secondary battery (or a secondary battery and a fuel cell),
electric vehicles, and fuel cell vehicles, etc.
[0006] One of such vehicular air-conditioning systems is a
heat-pump air-conditioning system. For example, as shown in FIG. 8
of the accompanying drawings, a cooling and heating system for use
on automobiles as disclosed in Japanese Patent No. 3929606 includes
a compressor 1, an exterior condenser 2, a liquid tank 3, an
expansion valve 4, and an interior evaporator 5 which are connected
successively in the order named by coolant pipes 6.
[0007] The cooling and heating system also includes a bypass pipe 7
for guiding a coolant discharged from the compressor 1 directly
into the liquid tank 3 in bypassing relation to the exterior
condenser 2. A first solenoid-operated valve 8a is connected to the
coolant pipe 6 that is connected to the inlet of the exterior
condenser 2. An interior condenser 2a and a second
solenoid-operated valve 8b are connected to the bypass pipe 7.
[0008] When the cooling and heating system operates in a cooling
mode, the first solenoid-operated valve 8a is opened and the second
solenoid-operated valve 8b is closed to deliver the coolant
discharged from the compressor 1 into the exterior condenser 2.
When the cooling and heating system operates in a heating mode, the
first solenoid-operated valve 8a is closed and the second
solenoid-operated valve 8b is opened to send the coolant discharged
from the compressor 1 into the bypass pipe 7.
[0009] The outlet of the exterior condenser 2 is directly connected
to the inlet of the compressor 1 by a coolant retrieval pipe 9
which is connected to a third solenoid-operated valve 8c. When the
heating mode is selected, the first solenoid-operated valve 8a, the
second solenoid-operated valve 8b, and the third solenoid-operated
valve 8c are controlled to retrieve the coolant which has remained
in the exterior condenser 2 into a heating cycle.
[0010] According to Japanese Patent No. 3929606, a receiver cycle
having the exterior condenser 2 and the liquid tank 3 which serves
as a receiver tank is employed. Therefore, cavitation (evaporation
of the liquid coolant) occurs in the liquid line, tending to cause
an insufficient coolant flow rate with respect to the opening of
the expansion valve 4.
[0011] The receiver cycle suffers from a relatively low cooling
capability. If the cooling capability is to be increased, then the
amount of coolant used and the weight of the cooling and heating
system are increased, making the cooling and heating system less
suitable for use on vehicles. Furthermore, the compressor 1 needs
an increase in its ability, which is detrimental to the fuel
economy of the vehicle that incorporates the cooling and heating
system.
SUMMARY OF THE INVENTION
[0012] It is an object of the present invention to provide a
vehicular air-conditioning system which is of a simple and
economical structure, allows a coolant to circulate stably, has an
increased heat exchange efficiency, and is capable of maintaining a
good air-conditioning capability.
[0013] According to the present invention, there is provided an
air-conditioning system for use on a vehicle, comprising a heat
pump circulation passage for circulating a coolant with a
compressor, a condenser disposed in the heat pump circulation
passage, for performing a heat exchange between the coolant and
ambient air, an expansion valve disposed in the heat pump
circulation passage, for depressurizing the coolant which is
delivered from the condenser, a first evaporator disposed in the
heat pump circulation passage, for performing a heat exchange
between the coolant which has passed through the expansion valve
and air-conditioning air, a heater disposed in the heat pump
circulation passage, for performing a heat exchange between the
coolant which is delivered from the compressor and the
air-conditioning air which has passed through the first evaporator,
and a second evaporator disposed in a branch passage branched from
the heat pump circulation passage, for performing a heat exchange
between the coolant and a heating medium obtained from within or
outside the vehicle.
[0014] The air-conditioning system also includes a gas-liquid
separator and an auxiliary condenser which are disposed downstream
of the condenser and connected between the condenser and the
expansion valve, and the heat pump circulation passage includes a
coolant retrieval passage extending from a divider between the
condenser and the gas-liquid separator and connected to the
compressor.
[0015] According to the present invention, the coolant that remains
in the condenser is retrieved to the compressor due to a pressure
difference which is developed in the coolant retrieval passage
connected between the condenser and the gas-liquid separator.
Therefore, the coolant that remains in the condenser is retrieved
easily and quickly for effectively preventing from dropping in
performance.
[0016] The auxiliary condenser is disposed downstream of the
gas-liquid separator with the divider being disposed upstream
thereof. The auxiliary condenser functions as an auxiliary cooling
unit when the air-conditioning system operates in a cooling mode
and a heating mode. There is no need for an auxiliary cooling unit
to be used exclusively in the heating mode, for example.
[0017] Accordingly, it is possible for the air-conditioning system
to circulate the coolant stably with a simple and economical
arrangement and to operate with increased heat exchange efficiency
for better air-conditioning capability.
[0018] The above and other objects, features, and advantages of the
present invention will become more apparent from the following
description when taken in conjunction with the accompanying
drawings in which preferred embodiments of the present invention
are shown by way of illustrative example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a diagram, partly in block form, of a vehicular
air-conditioning system according to a first embodiment of the
present invention;
[0020] FIG. 2 is a diagram of the vehicular air-conditioning system
shown in FIG. 1 which operates in a heating mode;
[0021] FIG. 3 is a flowchart of an operation sequence of the
vehicular air-conditioning system shown in FIG. 1;
[0022] FIG. 4 is a diagram of the vehicular air-conditioning system
shown in FIG. 1 which operates in a cooling mode;
[0023] FIG. 5 is a diagram, partly in block form, of a vehicular
air-conditioning system according to a second embodiment of the
present invention;
[0024] FIG. 6 is a diagram of the vehicular air-conditioning system
shown in FIG. 5 which operates in a heating mode;
[0025] FIG. 7 is a diagram of the vehicular air-conditioning system
shown in FIG. 5 which operates in a cooling mode; and
[0026] FIG. 8 is a diagram, partly in block form, of a cooling and
heating system for use on automobiles as disclosed in Japanese
Patent No. 3929606.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] As shown in FIGS. 1 and 2, a vehicular air-conditioning
system 10 according to a first embodiment of the present invention
is mounted on an automobile (vehicle) 12 for air-conditioning a
passenger's cabin (passenger compartment) 14 of the automobile
12.
[0028] The vehicular air-conditioning system 10 includes a heat
pump circulation passage 18 through which a coolant is circulated
by a compressor 16. To the heat pump circulation passage 18, there
are connected a condenser 20 for performing a heat exchange between
the coolant and the ambient air, an expansion valve 22 for
depressurizing the coolant sent from the condenser 20, a first
evaporator 24 for performing a heat exchange between the coolant
that has passed through the expansion valve 22 and air-conditioning
air, and a heater 26 for performing a heat exchange between the
coolant which has been delivered from the compressor 16 and the
air-conditioning air that has passed through the first evaporator
24.
[0029] A branch passage 28 is branched from the heat pump
circulation passage 18 and connected to a second evaporator 30 for
performing a heat exchange between the coolant and a heating medium
obtained from within or outside the automobile 12, e.g., a heating
medium discharged from the cabin 14 out of the automobile 12 (a
waste heat gas from the cabin 14).
[0030] Since the heating medium supplied to the second evaporator
30 for a heat exchange is a waste heat gas from the cabin 14, the
heat produced in the cabin 14 is not wasted but effectively
utilized. When the vehicular air-conditioning system 10 starts to
operate in a heating mode, the heat that is supplied to warm the
cabin 14 is retrieved and introduced back into the vehicular
air-conditioning system 10. Consequently, the vehicular
air-conditioning system 10 can quickly start to operate.
[0031] A first backflow check valve (backflow check means) 32a, a
gas-liquid separator 34, and an auxiliary condenser (auxiliary
cooling condenser) 36 are successively disposed downstream of the
condenser 20 and connected between the condenser 20 and the
expansion valve 22. The first backflow check valve 32a serves to
prevent the coolant from flowing from the gas-liquid separator 34
to the condenser 20. A solenoid-operated valve (on-off valve) 38a
is disposed upstream of the condenser 20. The heat pump circulation
passage 18 includes a first bypass passage 40a connected to the
gas-liquid separator 34 in bypassing relation to the condenser 20.
A solenoid-operated valve (on-off valve) 38b is connected to the
first bypass passage 40a.
[0032] The heat pump circulation passage 18 also includes a coolant
retrieval passage 44 extending from a divider 42 between the
condenser 20 and the gas-liquid separator 34 and connected to the
compressor 16. To the coolant retrieval passage 44, there are
connected a second backflow check valve (backflow check means) 32b
for preventing the coolant from flowing from the compressor 16 to
the divider 42, and a solenoid-operated valve (on-off valve)
38c.
[0033] The expansion valve 22 has a means (not shown) for detecting
the temperature of the coolant which is delivered from the first
evaporator 24 that cools the air-conditioning air. The expansion
valve 22 automatically changes its opening to change the flow rate
of the coolant depending on the detected temperature of the coolant
delivered from the first evaporator 24.
[0034] The heat pump circulation passage 18 has a three-way valve
46a connected at the junction between a portion of the heat pump
circulation passage 18 which is positioned near and connected to
the expansion valve 22 and an inlet end of the branch passage 28,
and a three-way valve 46b connected at the junction between an
outlet end of a second bypass passage 40b which bypasses the first
evaporator 24 and the heat pump circulation passage 18. The second
evaporator 30 is disposed in a rear portion of the automobile 12
(see FIG. 2).
[0035] An air-mixing damper 48 for delivering the air-conditioning
air which has been cooled by the first evaporator 24 into the cabin
14 without flowing through the heater 26 is disposed between the
first evaporator 24 and the heater 26.
[0036] The automobile 12 has an ambient air inlet 50 for
introducing ambient air as air-conditioning air into the cabin 14.
The first evaporator 24 and the heater 26 are disposed successively
in the order named downstream of the ambient air inlet 50. The
vehicular air-conditioning system 10 also includes a controller
(ECU) 52 (see FIG. 1) for controlling overall operation of the
vehicular air-conditioning system 10. The controller 52 also
functions as a flow passage switching means for controlling the
solenoid-operated valves 38a, 38b, 38c and the three-way valves
46a, 46b to switch between a heating mode and a cooling mode of the
vehicular air-conditioning system 10.
[0037] Operation of the vehicular air-conditioning system 10 will
be described below with reference to a flowchart shown in FIG.
3.
[0038] First, it is determined whether the heating mode or the
cooling mode of the vehicular air-conditioning system 10 is
selected in step S1. If the heating mode is selected (YES in step
S1), then control goes to step S2 in which the solenoid-operated
valve 38a is closed and the solenoid-operated valves 38b, 38c are
opened.
[0039] Then, the compressor 16 is activated in step S3. The
compressor 16 now delivers the coolant into the heat pump
circulation passage 18. The coolant is supplied to the heater 26
which performs a heat exchange between the coolant and the
air-conditioning air, i.e., radiates the heat from the coolant to
the air-conditioning air, thereby increasing the temperature of the
air-conditioning air.
[0040] As the solenoid-operated valve 38a is closed and the
solenoid-operated valve 38b is open, the coolant discharged from
the heater 26 flows through the first bypass passage 40a into the
gas-liquid separator 34 in bypassing relation to the condenser 20.
The coolant is cooled while it flows through the gas-liquid
separator 34 and the auxiliary condenser 36, and then is sent to
the expansion valve 22.
[0041] The coolant is depressurized by the expansion valve 22 and
flows through the three-way valve 46a into the branch passage 28,
from which the coolant is introduced into the second evaporator 30.
The second evaporator 30 performs a heat exchange between the
coolant and the heat from the cabin 14. The coolant then flows from
the second evaporator 30 and through the second bypass passage 40b
and the expansion valve 22 in bypassing relation to the first
evaporator 24, and is then delivered again to the compressor
16.
[0042] According to the first embodiment, the coolant retrieval
passage 44 extends from the divider 42 between the condenser 20 and
the gas-liquid separator 34 and is connected to the compressor 16,
and the solenoid-operated valve 38c connected to the coolant
retrieval passage 44 is open at this time.
[0043] When the compressor 16 is actuated while in the heating
mode, a pressure difference is developed in the coolant retrieval
passage 44. Specifically, in the coolant retrieval passage 44, the
pressure at the compressor 16 is lower than the pressure at the
divider 42. Therefore, the coolant in the form of a liquid which
remains in the condenser 20 is forcibly drawn, i.e., retrieved,
toward the compressor 16 through the coolant retrieval passage 44
due to the pressure difference in the coolant retrieval passage 44.
Accordingly, the coolant in the form of a liquid which remains in
the condenser 20 is easily and quickly retrieved, and the condenser
20 is prevented from dropping in performance.
[0044] In the heating mode, the heater 26 is connected downstream
directly to the gas-liquid separator 34 in bypassing relation to
the condenser 20. Therefore, the gas-liquid separator 34 functions
as an auxiliary cooling tank, and the auxiliary condenser 36
functions as an auxiliary cooling unit.
[0045] The coolant is thus introduced as a fully liquid medium into
the expansion valve 22, with any gas being prevented from being
trapped therein. The coolant is thus stably circulated in the heat
pump circulation passage 18 for higher heat exchange
efficiency.
[0046] Since the gas-liquid separator 34 functions as an auxiliary
cooling tank, a sufficient amount of coolant is maintained in the
vehicular air-conditioning system 10. Consequently, the vehicular
air-conditioning system 10 is prevented from dropping in
air-conditioning performance due to a shortage of coolant while the
vehicular air-conditioning system 10 is operating in a transient
period.
[0047] In the first embodiment, there is no need for an auxiliary
cooling tank and an auxiliary cooling unit to be used exclusively
in the heating mode because the gas-liquid separator 34 and the
auxiliary condenser 36 can be used also in the cooling mode.
Accordingly, it is possible for the vehicular air-conditioning
system 10 to circulate the coolant stably with a simple and
economical arrangement and to operate with increased heat exchange
efficiency for better air-conditioning capability.
[0048] If the compressor 16 has been actuated for a given time
(prescribed time) (YES in step S4), then control goes to step S5 in
which the solenoid-operated valve 38c is closed. Thus, the coolant
stops being retrieved from the condenser 20, and the vehicular
air-conditioning system 10 enters a normal heating mode. If it is
judged that the heating mode is stopped (YES in step S6), then the
vehicular air-conditioning system 10 is shut down.
[0049] If the heating mode is not selected (NO in step S1), then
control goes to step S7 which determines whether the cooling mode
of the vehicular air-conditioning system 10 is selected or not. If
it is judged that the cooling mode is not selected (NO in step S7),
then control jumps to step S6. If it is judged that the cooling
mode is selected (YES in step S7), then control goes to step
S8.
[0050] In step S8, the solenoid-operated valve 38a is opened and
the solenoid-operated valves 38b, 38c are closed. Then, control
goes to step S9 in which the compressor 16 is activated. The
vehicular air-conditioning system 10 now starts to operate in the
cooling mode, as shown in FIG. 4.
[0051] In the cooling mode, the solenoid-operated valve 38a is
opened to connect the condenser 20 to the heat pump circulation
passage 18. The three-way valves 46a, 46b are switched to
disconnect the branch passage 28 from the heat pump circulation
passage 18 and connect the first evaporator 24 to the heat pump
circulation passage 18. The air-mixing damper 48 is brought into a
fully closed position, i.e., a position to cover the heater 26.
[0052] The coolant which has been compressed and heated to a higher
temperature by the compressor 16 flows through the heater 26 and is
cooled by the condenser 20, the gas-liquid separator 34, and the
auxiliary condenser 36. The coolant becomes lower in temperature
and pressure in the expansion valve 22, and then is supplied to the
first evaporator 24. The first evaporator 24 performs a heat
exchange between the coolant which is lower in temperature and
pressure and the air-conditioning air, thereby cooling the
air-conditioning air. After having absorbed the heat from the
air-conditioning air, the coolant is returned from the expansion
valve 22 to the compressor 16.
[0053] Inasmuch as the air-mixing damper 48 is closed, the
air-conditioning air cooled by the first evaporator 24 is not
heated by the heater 26, and is introduced into the cabin 14,
cooling the cabin 14. In the cooling mode, the gas-liquid separator
34 provides a damping action on the coolant as it increases or
decreases in volume.
[0054] FIG. 5 is a diagram, partly in block form, of a vehicular
air-conditioning system 60 according to a second embodiment of the
present invention. Those parts of the vehicular air-conditioning
system 60 which are identical to those of the vehicular
air-conditioning system 10 according to the first embodiment are
denoted by identical reference characters, and will not be
described in detail below.
[0055] The vehicular air-conditioning system 60 is mounted on an
automobile (vehicle) 62 (see FIG. 6). As shown in FIGS. 5 and 6,
the heat pump circulation passage 18 includes a condenser unit 64
as an auxiliary cooling condenser, which provides an auxiliary
cooling cycle. The condenser unit 64 is disposed downstream of the
heater 26 and is connected in series thereto. The condenser unit 64
comprises a main condenser (condensing unit) 20a, a gas-liquid
separating coolant storage (auxiliary cooling tank) 34a, and an
auxiliary condenser (supercooling unit) 36a, through which the
coolant flows in the cooling mode.
[0056] The heat pump circulation passage 18 includes a coolant
retrieval passage 44a extending from a divider 42a at an end of the
main condenser 20a and connected to the compressor 16. The second
backflow check valve 32b and the solenoid-operated valve 38c are
connected to the coolant retrieval passage 44a.
[0057] According to the second embodiment, the vehicular
air-conditioning system 60 operates in the heating mode and the
cooling mode according to the flowchart shown in FIG. 3, as with
the vehicular air-conditioning system 10 according to the first
embodiment.
[0058] When the vehicular air-conditioning system 60 operates in
the heating mode, as shown in FIG. 6, the solenoid-operated valve
38a is closed and the solenoid-operated valves 38b, 38c are opened.
In the heating mode, the coolant in the form of a liquid which
remains in the condenser 20 is forcibly drawn toward the compressor
16 due to the pressure difference in the coolant retrieval passage
44a. Consequently, the vehicular air-conditioning system 60
according to the second embodiment offers the same advantages as
the vehicular air-conditioning system 10 according to the first
embodiment, e.g., it allows the coolant in the form of a liquid to
be well and reliably retrieved.
[0059] When the vehicular air-conditioning system 60 operates in
the cooling mode, as shown in FIG. 7, the solenoid-operated valve
38a is opened and the solenoid-operated valves 38b, 38c are closed.
Therefore, the vehicular air-conditioning system 60 according to
the second embodiment offers the same advantages as the vehicular
air-conditioning system 10 according to the first embodiment.
[0060] In each of the first and second embodiments, the heating
medium supplied to the second evaporator 30 for a heat exchange may
be any medium which is higher in temperature than the coolant that
flows into the second evaporator 30, e.g., a medium heated by
motors, a medium heated by batteries, a medium heated by an
internal combustion engine if the automobile 12 or 62 is powered by
such an internal combustion engine, a medium heated by the
controller 52, a medium carrying ambient heat, or the like, in
addition to the waste heat gas from the cabin 14.
[0061] Each of the three-way valves 46a, 46b may comprise an
integral structure including a three-way dividing mechanism and a
valve mechanism or a combination of a dividing block and a
solenoid-operated valve.
[0062] Although certain preferred embodiments of the present
invention have been shown and described in detail, it should be
understood that various changes and modifications may be made
therein without departing from the scope of the appended
claims.
* * * * *