U.S. patent application number 13/703216 was filed with the patent office on 2013-04-04 for heat pump cycle.
This patent application is currently assigned to DENSO CORPORATION. The applicant listed for this patent is Satoshi Itoh, Yoshiki Katoh. Invention is credited to Satoshi Itoh, Yoshiki Katoh.
Application Number | 20130081419 13/703216 |
Document ID | / |
Family ID | 45097819 |
Filed Date | 2013-04-04 |
United States Patent
Application |
20130081419 |
Kind Code |
A1 |
Katoh; Yoshiki ; et
al. |
April 4, 2013 |
HEAT PUMP CYCLE
Abstract
In a heat pump cycle, refrigerant tubes of an outdoor heat
exchanger serving as an evaporator for evaporating refrigerant, and
cooling fluid tubes of a radiator for dissipating heat from a
coolant of an electric motor for traveling serving as an external
heat source are bonded to the same outer fins. The heat contained
in the coolant flowing through the cooling fluid tubes can be
transferred to the refrigerant tubes of the outdoor heat exchanger
via the outer fins. Thus, in the defrosting operation which
involves defrosting the outdoor heat exchanger by flowing the
coolant through the radiator, the loss in transfer of the heat
contained in the coolant to the outdoor heat exchanger can be
suppressed, and the heat supplied from the electric motor for
traveling can be effectively used for defrosting the outdoor heat
exchanger.
Inventors: |
Katoh; Yoshiki; (Chita-gun,
JP) ; Itoh; Satoshi; (Kariya-city, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Katoh; Yoshiki
Itoh; Satoshi |
Chita-gun
Kariya-city |
|
JP
JP |
|
|
Assignee: |
DENSO CORPORATION
Kariya-city, Aichi-pref.
JP
|
Family ID: |
45097819 |
Appl. No.: |
13/703216 |
Filed: |
June 9, 2011 |
PCT Filed: |
June 9, 2011 |
PCT NO: |
PCT/JP2011/003257 |
371 Date: |
December 10, 2012 |
Current U.S.
Class: |
62/278 |
Current CPC
Class: |
F25B 30/02 20130101;
B60H 1/004 20130101; F25B 2400/0411 20130101; F25B 47/02 20130101;
B60H 2001/00961 20190501; F25B 5/00 20130101; B60H 2001/00949
20130101; F25B 47/025 20130101; B60H 1/00921 20130101 |
Class at
Publication: |
62/278 |
International
Class: |
F25B 47/02 20060101
F25B047/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 10, 2010 |
JP |
2010-132891 |
Jun 1, 2011 |
JP |
2011-123199 |
Claims
1-26. (canceled)
27. A heat pump cycle comprising: a compressor compressing and
discharging refrigerant; a user-side heat exchanger exchanging heat
between the refrigerant discharged from the compressor and a heat
exchange fluid; a decompression device decompressing the
refrigerant flowing from the user-side heat exchanger; an outdoor
heat exchanger which causes the refrigerant decompressed by the
decompression device to exchange heat with outside air and to be
evaporated, the heat pump cycle being adapted to perform a
defrosting operation for defrosting the outdoor heat exchanger when
the outdoor heat exchanger is frosted; an indoor evaporator for
allowing the refrigerant on a downstream side of the outdoor heat
exchanger to exchange heat with the heat exchange fluid and to be
evaporated; a refrigerant flow path switching device configured to
switch a refrigerant flow path in a heating operation in which the
refrigerant discharged from the compressor flows into the user-side
heat exchanger to heat the heat exchange fluid, and a refrigerant
flow path in a cooling operation in which the refrigerant
dissipating heat therefrom at the outdoor heat exchanger flows into
the indoor evaporator to cool the heat exchange fluid, a
heat-dissipation heat exchanger, disposed in a cooling fluid
circulation circuit for circulating a cooling fluid for cooling an
external heat source, the heat-dissipation heat exchanger being
adapted to exchange heat between the cooling fluid and the outside
air; and a cooling fluid circuit switching device configured to
switch between a cooling fluid circuit for allowing the cooling
fluid to flow into the heat-dissipation heat exchanger, and a
cooling fluid circuit for allowing the cooling fluid to bypass the
heat-dissipation heat exchanger, wherein the outdoor heat exchanger
includes a refrigerant tube in which the refrigerant decompressed
by the decompression device flows, a heat-absorption air passage
for flowing the outside air is formed around the refrigerant tube,
the heat-dissipation heat exchanger includes a cooling fluid tube
in which the cooling fluid flows, a heat-dissipation air passage
for flowing the outside air is formed around the cooling fluid
tube, the heat-absorption air passage and the heat-dissipation air
passage are provided with an outer fin that enables heat transfer
between the refrigerant tube and the cooling fluid tube, while
promoting heat exchange in both of the outdoor heat exchanger and
the heat-dissipation heat exchanger, the cooling fluid circuit
switching device performs switching to the cooling fluid circuit
for flowing the cooling fluid into the heat-dissipation heat
exchanger in at least the defrosting operation, a flow direction of
the refrigerant flowing through the refrigerant tube in the heating
operation is the same as that of the refrigerant flowing through
the refrigerant tube in the cooling operation, a heat exchange
region at a refrigerant inlet side of the outdoor heat exchanger is
overlapped in an outside air flow direction with a heat exchange
region at a cooling fluid inlet side of the heat dissipation heat
exchanger, the outdoor heat exchanger is configured, such that
relatively high-temperature refrigerant flows through the heat
exchange region at the refrigerant inlet side of the outdoor heat
exchanger in the cooling operation, and relatively low-temperature
refrigerant flows through the heat exchange region at the
refrigerant inlet side of the outdoor heat exchanger in the heating
operation, and the heat dissipation heat exchanger is configured,
such that relatively high-temperature cooling fluid flows through
the heat exchange region at the refrigerant inlet side of the heat
dissipation heat exchanger in both the cooling operation and the
heating operation.
28. The heat pump cycle according to claim 27, wherein in the
defrosting operation, an inflow rate of the refrigerant flowing
into the outdoor heat exchanger is decreased as compared to before
transfer to the defrosting operation.
29. The heat pump cycle according to claim 27, wherein the
decompression device is a variable throttle mechanism in which a
throttle opening degree is variable, and the decompression device
increases the throttle opening degree in the defrosting operation
as compared to before transfer to the defrosting operation.
30. The heat pump cycle according to claim 27, further comprising
an outflow rate adjustment valve configured to adjust an outflow
rate of the refrigerant flowing from the outdoor heat exchanger,
wherein the outflow rate adjustment valve decreases the outflow
rate of the refrigerant in the defrosting operation as compared to
before transfer to the defrosting operation.
31. The heat pump cycle according to claim 30, wherein the outflow
rate adjustment valve is configured integrally with an outlet for
the refrigerant of the outdoor heat exchanger.
32. The heat pump cycle according to claim 27, further comprising
an outdoor blower which blows the outside air toward both the
outdoor heat exchanger and the heat-dissipation heat exchanger,
wherein the outdoor blower increases an air blowing capacity when
the compressor is stopped, as compared to before stopping the
compressor.
33. The heat pump cycle according to claim 27, wherein in the
defrosting operation, a heating capacity of the user-side heat
exchanger for heating the heat exchange fluid is decreased as
compared to before transfer to the defrosting operation.
34. The heat pump cycle according to claim 27, wherein the
heat-absorption air passage and the heat-dissipation air passage
are configured such that volumes of the outside air flowing into
the heat-absorption air passage and the heat-dissipation air
passage are decreased in the defrosting operation.
35. The heat pump cycle according to claim 27, further comprising
an outdoor blower which blows the outside air toward both the
outdoor heat exchanger and the heat-dissipation heat exchanger,
wherein the heat-dissipation heat exchanger is located on a
windward side in the flow direction of the outside air blown by the
outdoor blower with respect to the outdoor heat exchanger.
36. The heat pump cycle according to claim 27, wherein at least one
of the refrigerant tubes is located between the cooling fluid
tubes, at least one of the cooling fluid tubes is located between
the refrigerant tubes, and at least one of the heat-absorption air
passage and the heat-dissipation air passage is formed as one air
passage.
37. The heat pump cycle according to claim 27 being applied to an
air conditioner for a vehicle, the heat pump cycle further
comprising: an inside air temperature detection portion configured
to detect an inside air temperature of a vehicle interior; and a
frost formation determination portion configured to determine frost
formation of the outdoor heat exchanger, wherein the heat exchange
fluid is air blown into the vehicle interior, the external heat
source is a vehicle-mounted device generating heat in operation,
the cooling fluid is a coolant for cooling the vehicle-mounted
device, and the cooling fluid circuit switching device performs
switching to the cooling fluid circuit for flowing the cooling
fluid into the heat-dissipation heat exchanger when the frost is
determined to be formed at the outdoor heat exchanger by the frost
formation determination portion and an inside air temperature of
the vehicle interior is equal to or more than a predetermined
reference inside air temperature.
38. The heat pump cycle according to claim 27 being applied to an
air conditioner for a vehicle, the heat pump cycle further
comprising a frost formation determination portion for determining
frost formation of the outdoor heat exchanger, wherein the heat
exchange fluid is air blown into the vehicle interior, the external
heat source is a vehicle-mounted device generating heat in
operation, the cooling fluid is a coolant for cooling the
vehicle-mounted device, the user-side heat exchanger is disposed in
a casing forming therein an air passage, an inside/outside air
switching device for changing a ratio of introduction of inside air
to outside air to be introduced into the casing is disposed in the
casing, wherein the cooling fluid circuit switching device performs
switching to the cooling fluid circuit for flowing the cooling
fluid to the heat-dissipation heat exchanger when the frost is
determined to be formed at the outdoor heat exchanger by the frost
formation determination portion, and the inside/outside air
switching device increases the ratio of introduction of the inside
air to the outside air as compared to before transfer to the
defrosting operation when the frost is determined to be formed at
the outdoor heat exchanger by the frost formation determination
portion.
39. The heat pump cycle according to claim 27 being applied to an
air conditioner for a vehicle, the heat pump cycle further
comprising a frost formation determination portion configured to
determine frost formation of the outdoor heat exchanger, wherein
the heat exchange fluid is air blown into the vehicle interior, the
external heat source is a vehicle-mounted device generating heat in
operation, the cooling fluid is a coolant for cooling the
vehicle-mounted device, the user-side heat exchanger is disposed in
a casing forming therein an air passage, an air outlet mode
switching device for switching among air outlet modes by changing
opening/closing states of air outlets for blowing the air into the
vehicle interior is disposed in the casing, at least a foot air
outlet for blowing the air to a foot of a passenger is provided as
the air outlet, the cooling fluid circuit switching device performs
switching to the cooling fluid circuit for flowing the cooling
fluid into the heat-dissipation heat exchanger when the frost is
determined to be formed at the outdoor heat exchanger by the frost
formation determination portion, and the air outlet mode switching
device performs switching to the air outlet mode for blowing the
air from the foot air outlet when the frost is determined to be
formed at the outdoor heat exchanger by the frost formation
determination portion.
40. The heat pump cycle according to claim 27 being applied to an
air conditioner for a vehicle, the heat pump cycle further
comprising a frost formation determination portion configured to
determine frost formation of the outdoor heat exchanger, wherein
the heat exchange fluid is air blown into the vehicle interior, the
external heat source is a vehicle-mounted device generating heat in
operation, the cooling fluid is a coolant for cooling the
vehicle-mounted device, the user-side heat exchanger is disposed in
a casing for forming therein an air passage, a blower for blowing
air toward the vehicle interior is disposed in the casing, the
cooling fluid circuit switching device performs switching to the
cooling fluid circuit for flowing the cooling fluid into the
heat-dissipation heat exchanger when the frost is determined to be
formed at the outdoor heat exchanger by the frost formation
determination portion, and the blower decreases an air blowing
capacity, as compared to before the determination of the frost
formation.
41. The heat pump cycle according to claim 27 being applied to an
air conditioner for a vehicle, the heat pump cycle further
comprising a frost formation determination portion for determining
frost formation of the outdoor heat exchanger, wherein the heat
exchange fluid is air blown into the vehicle interior, the external
heat source is a vehicle-mounted device generating heat in
operation, the cooling fluid is a coolant for cooling the
vehicle-mounted device, the frost formation determination portion
determines that the frost is formed at the outdoor heat exchanger,
when a vehicle speed is equal to or less than a predetermined
reference speed, and when a temperature of the refrigerant on an
outlet side of the outdoor heat exchanger is equal to or less than
0.quadrature..quadrature.C, and the cooling fluid circuit switching
device performs switching to a cooling fluid circuit for flowing
the cooling fluid into the heat-dissipation heat exchanger when the
frost is determined to be formed at the outdoor heat exchanger by
the frost formation determination portion.
42. The heat pump cycle according to claim 41, wherein the frost
formation determination portion determines that the frost is formed
at the outdoor heat exchanger, when the speed of the traveling
vehicle is equal to or less than the predetermined reference speed,
and when the temperature of the refrigerant on the outlet side of
the outdoor heat exchanger is equal to or less than
0.quadrature..quadrature.C.
43. The heat pump cycle according to claim 37, further comprising a
coolant temperature detection portion configured to detect a
temperature of the coolant flowing into a vehicle-mounted device,
wherein the cooling fluid circuit switching device performs
switching to the cooling fluid circuit for flowing the cooling
fluid into the heat-dissipation heat exchanger when a coolant
temperature detected by the coolant temperature detection portion
is equal to or more than the predetermined reference
temperature.
44. The heat pump cycle according to claim 27, wherein the cooling
fluid circulation circuit stores therein the heat contained in the
external heat source when the cooling fluid circuit switching
device performs switching to the cooling fluid circuit for allowing
the cooling fluid to bypass the heat-dissipation heat
exchanger.
45. The heat pump cycle according to claim 44 being applied to an
air conditioner for a vehicle, wherein the heat exchange fluid is
air blown into the vehicle interior, the external heat source is a
vehicle-mounted device generating heat in operation, the cooling
fluid is a coolant for cooling the vehicle-mounted device, and the
cooling fluid circulation circuit stores heat dissipated from the
vehicle-mounted device in the coolant when the cooling fluid
circuit switching device performs switching to the cooling fluid
circuit for allowing the cooling fluid to bypass the
heat-dissipation heat exchanger.
46. The heat pump cycle according to claim 44 being applied to an
air conditioner for a vehicle, wherein the heat exchange fluid is
air blown into the vehicle interior, the external heat source is a
heating element for generating heat by being supplied with power,
the cooling fluid is a coolant for cooling the heating element, and
the cooling fluid circulation circuit stores the heat dissipated
from the heating element in the coolant when the cooling fluid
circuit switching device performs switching to the cooling fluid
circuit for allowing the cooling fluid to bypass the
heat-dissipation heat exchanger.
47. The heat pump cycle according to claim 44 being applied to an
air conditioner for a vehicle, wherein the heat exchange fluid is
air blown into the vehicle interior, a vehicle-mounted device
generating heat in operation, and a heating element for generating
heat by being supplied with power are provided as the external heat
source, the cooling fluid is a coolant for cooling the heating
element and the vehicle-mounted device, and the cooling fluid
circulation circuit stores the heat dissipated from at least one of
the vehicle-mounted device and the heating element in the coolant
when the cooling fluid circuit switching device performs switching
to the cooling fluid circuit for allowing the cooling fluid to
bypass the heat-dissipation heat exchanger.
48. The heat pump cycle according to claim 46, wherein the heating
element has an amount of generated heat therefrom controlled based
on an outside air temperature.
49. The heat pump cycle according to claim 27, further comprising:
an outdoor unit bypass passage which causes the refrigerant
decompressed by the decompression device to bypass the outdoor heat
exchanger and to guide the refrigerant to a refrigerant outlet side
of the outdoor heat exchanger; and an outdoor-unit bypass passage
switching device configured to switch between a refrigerant circuit
for guiding the refrigerant decompressed by the decompression
device to the outdoor heat exchanger, and a refrigerant circuit for
guiding the refrigerant decompressed by the decompression device
toward the outdoor unit bypass passage, wherein in the defrosting
operation, the outdoor unit bypass passage switching device
performs switching to the refrigerant circuit for guiding the
refrigerant decompressed by the decompression device to the outdoor
unit bypass passage.
50. The heat pump cycle according to claim 27, further comprising:
an indoor evaporator which exchanges heat between the refrigerant
on a downstream side of the outdoor heat exchanger and the heat
exchange fluid; an evaporator bypass passage which causes the
refrigerant on the downstream side of the outdoor heat exchanger to
bypass the indoor evaporator and to guide the refrigerant to a
refrigerant outlet of the indoor evaporator; and an evaporator
bypass passage switching device configured to switch a refrigerant
circuit for guiding the refrigerant on the downstream side of the
outdoor heat exchanger to the indoor evaporator, and a refrigerant
circuit for guiding the refrigerant on the downstream side of the
outdoor heat exchanger to the evaporator bypass passage, wherein in
the defrosting operation, the evaporator bypass passage switching
device performs switching to the refrigerant circuit for guiding
the refrigerant on the downstream side of the outdoor heat
exchanger to the indoor evaporator.
51. The heat pump cycle according to claim 27 being applied to an
air conditioner for a vehicle, wherein the heat exchange fluid is
air blown into the vehicle interior, the user-side heat exchanger
is disposed in a casing for forming therein an air blowing passage,
and in the casing, an auxiliary heater is provided for heating the
air blown into the vehicle interior using as a heating source, at
least one of a heating fluid heated by a vehicle-mounted device
that generates heat in operation, and a heating element that
generates heat by being supplied with power.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Applications
No. 2010-132891 filed on Jun. 10, 2010, and No. 2011-123199 filed
on Jun. 1, 2011, the contents of which are incorporated herein by
reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a heat pump cycle for
performing a defrosting operation to remove frost formed in a heat
exchanger serving as an evaporator. More specifically, the
invention relates to a heat pump cycle suitably used for an air
conditioner for a vehicle that has a difficulty in obtaining a heat
source for heating from a driving source for traveling.
BACKGROUND OF THE INVENTION
[0003] Conventionally, Patent Document 1 discloses a vapor
compression refrigeration cycle (heat pump cycle) that performs a
defrosting operation for melting and removing frost formed in a
heat exchanger serving as an evaporator for evaporating
refrigerant.
[0004] The heat pump cycle disclosed in Patent Document 1 is
applied to an air conditioner for a hybrid car. The heat pump cycle
is designed to be capable of switching between a heating operation
for heating the interior of a vehicle by heating air blown into a
vehicle compartment as a heat exchange fluid, and a defrosting
operation for removing frost formed in an outdoor heat exchanger
serving as the evaporator in the heating operation.
[0005] More specifically, in the defrosting operation, when the
frost formation of the outdoor heat exchanger is detected, an
internal combustion engine (engine) for outputting a driving force
for vehicle traveling is initiated, and warm air blown from a
radiator for dissipating heat from an engine coolant is blown into
the outdoor heat exchanger to thereby defrost the outdoor heat
exchanger.
[0006] In short, the heat pump cycle disclosed in Patent Document 1
is designed to remove the frost formed in the outdoor heat
exchanger by melting the frost using waste heat of the engine as an
external heat source.
PRIOR ART DOCUMENT
[0007] Patent Document 1: Japanese Unexamined Patent Publication
No. 2008-221997
[0008] However, the structure for transferring heat absorbed by the
coolant from the engine to the evaporator via air might dissipate
heat from the air (warm air) heated by the radiator into ambient
air, thereby leading to the loss in heat transfer, as in Patent
Document 1. In some cases, the waste heat from the engine as the
external heat source cannot be effectively used for defrosting the
evaporator.
[0009] As mentioned above, the waste heat from the engine cannot be
effectively used for defrosting the evaporator, which takes a long
time to perform the defrosting. And, during the defrosting
operation, the engine has to continue working, causing the
deterioration of the fuel efficiency of the vehicle. When the
heating operation is stopped during the defrosting operation, a
passenger cannot feel warm enough.
SUMMARY OF THE INVENTION
[0010] The present invention has been made in view of the forgoing
points, and it is a first object of the present invention to
provide a heat pump cycle that can effectively use the heat
supplied from an external heat source during a defrosting
operation.
[0011] Further, it is a second object of embodiments of the
invention to provide a heat pump cycle applied to an air
conditioner for a vehicle, which can achieve both the effective use
of heat supplied from the external heat source, and the prevention
of insufficient heating to a passenger during a defrosting
operation.
[0012] To achieve the above object, according to a first exemplar
of the present invention, a heat pump cycle includes: a compressor
compressing and discharging refrigerant; a user-side heat exchanger
exchanging heat between the refrigerant discharged from the
compressor and a heat exchange fluid; a decompression device
decompressing the refrigerant flowing from the user-side heat
exchanger; and an outdoor heat exchanger which causes the
refrigerant decompressed by the decompression device to exchange
heat with outside air and to be evaporated. The heat pump cycle is
adapted to perform a defrosting operation for defrosting the
outdoor heat exchanger when the outdoor heat exchanger is frosted.
The heat pump cycle further includes a heat-dissipation heat
exchanger and a cooling fluid circuit switching device. The
heat-dissipation heat exchanger is disposed in a cooling fluid
circulation circuit for circulating a cooling fluid for cooling an
external heat source, and is adapted to exchange heat between the
cooling fluid and outside air. The cooling fluid circuit switching
device is configured to switch between a cooling fluid circuit for
allowing the cooling fluid to flow into the heat-dissipation heat
exchanger, and a cooling fluid circuit for allowing the cooling
fluid to bypass the heat-dissipation heat exchanger. In the heat
pump cycle, the outdoor heat exchanger includes a refrigerant tube
in which the refrigerant decompressed by the decompression device
flows, a heat-absorption air passage for flowing the outside air is
formed around the refrigerant tube, the heat-dissipation heat
exchanger includes a cooling fluid tube in which the cooling fluid
flows, a heat-dissipation air passage for flowing the outside air
is formed around the cooling fluid tube, the heat-absorption air
passage and the heat-dissipation air passage are provided with an
outer fin that enables heat transfer between the refrigerant tube
and the cooling fluid tube while promoting heat exchange in both of
the outdoor heat exchanger and the heat-dissipation heat exchanger,
and the cooling fluid circuit switching device performs switching
to the cooling fluid circuit for flowing the cooling fluid into the
heat-dissipation heat exchanger in at least the defrosting
operation.
[0013] Because the cooling fluid circuit switching device performs
switching to the cooling fluid circuit for flowing the cooling
fluid into the heat-dissipation heat exchanger during the
defrosting operation, the heat contained in the cooling fluid
flowing through the cooling fluid tube can be transferred to the
outdoor heat exchanger to defrost the outdoor heat exchanger.
[0014] At this time, outer fins are provided in the heat-absorption
air passage and another heat-dissipation air passage to enable heat
transfer between one refrigerant tube and another cooling fluid
tube. Via the outer fins, the heat of the cooling fluid can be
transferred to the outdoor heat exchanger.
[0015] As compared to the related art structure in which heat
contained in the cooling fluid is transferred to the outdoor heat
exchanger via air, the loss in heat transfer can be suppressed, and
thus the heat supplied from the external heat source can be
effectively used to defrost the outdoor heat exchanger during the
defrosting operation. Further, the reduction in time required for
the defrosting operation can also be achieved.
[0016] According to a second exemplar of the present invention, the
heat pump cycle of the above first exemplar further includes: an
indoor evaporator for allowing the refrigerant on a downstream side
of the outdoor heat exchanger to exchange heat with the heat
exchange fluid and to be evaporated; and a refrigerant flow path
switching device configured to switch a refrigerant flow path in
the heating operation in which the refrigerant discharged from the
compressor flows into the user-side heat exchanger to heat the heat
exchange fluid, and a refrigerant flow path in the cooling
operation in which the refrigerant dissipating heat therefrom at
the outdoor heat exchanger flows into the indoor evaporator to cool
the heat exchange fluid. Furthermore, a flow direction of the
refrigerant flowing through the refrigerant tube in the heating
operation is the same as that of the refrigerant flowing through
the refrigerant tube in the cooling operation.
[0017] This arrangement of the heap pump cycle can heat the heat
exchange fluid by the user-side heat exchanger. Additionally, the
heat pump cycle also includes an indoor heat exchanger, and thus
can also cool the heat exchange fluid by use of the indoor heat
exchanger.
[0018] During the heating operation, the flow direction of
refrigerant flowing through the refrigerant tube is the same as
that of refrigerant flowing through the refrigerant tube during the
cooling operation. As viewed from the flow direction of the outside
air, the positional relationship between a heat exchange region on
a refrigerant inlet side of the outdoor heat exchanger and a heat
exchange region on a refrigerant outlet side thereof does not
change between the heating operation and the cooling operation.
[0019] Thus, the outdoor heat exchanger and the heat-dissipation
heat exchanger are macroscopically regarded as one heat exchanger.
In the cooling operation for dissipating heat from the refrigerant
by the outdoor heat exchanger, a heat exchange region on the
refrigerant inlet side of the outdoor heat exchanger for flowing
the refrigerant having a superheat degree at a relatively high
temperature is superimposed in the flow direction of the outside
air, on a heat exchange region on the cooling fluid inlet side of
the heat-dissipation heat exchanger for flowing the cooling fluid
at a relatively high temperature. Further, a heat exchange region
on the refrigerant outlet side of the outdoor heat exchanger for
flowing the refrigerant having a superheat degree at a relatively
low temperature is superimposed in the flow direction of the
outside air, on a heat exchange region on the cooling fluid outlet
side of the heat-dissipation heat exchanger for flowing the cooling
fluid at a relatively low temperature. With this arrangement, the
flow of the refrigerant and the flow of the cooling fluid flowing
through both heat exchangers can be made parallel.
[0020] Further, with this arrangement, in the heating operation for
evaporating the refrigerant by the outdoor heat exchanger, the heat
exchange region on the refrigerant inlet side of the outdoor heat
exchanger through which the refrigerant flows at a relatively low
temperature can be superimposed on the heat exchange region on the
cooling fluid inlet side of the heat-dissipation heat exchanger
through which the cooling fluid flows at a relatively high
temperature, in the flow direction of the outside air. Thus, the
heat pump cycle of this embodiment can effectively suppress the
frost formation caused in the heat exchange region on the
refrigerant inlet side of the outdoor heat exchanger through which
the refrigerant flows at a relatively low temperature.
[0021] According to a third exemplar of the present invention, the
heat pump cycle of the above first or second exemplar is configured
such that, in the defrosting operation, an inflow rate of the
refrigerant flowing into the outdoor heat exchanger is decreased as
compared to before transfer to the defrosting operation.
[0022] Thus, in the defrosting operation, heat transmitted to the
outdoor heat exchanger via outer fins can be prevented from being
absorbed in the refrigerant flowing through the refrigerant tube of
the outdoor heat exchanger. As a result, the heat supplied from the
external heat source can be used more effectively to defrost the
outdoor heat exchanger during the defrosting operation.
[0023] Furthermore, as in a fourth exemplar of the present
invention, the decompression device may be a variable throttle
mechanism in which a throttle opening degree is variable, and the
decompression device may increase the throttle opening degree in
the defrosting operation as compared to before transfer to the
defrosting operation. Thus, in the defrosting operation,
high-temperature refrigerant discharged from the compressor can
readily flow to the outdoor heat exchanger, thereby accelerating
defrosting of the outdoor heat exchanger.
[0024] Furthermore, as in a fifth exemplar of the present
invention, the heat pump cycle may further include an outflow rate
adjustment valve configured to adjust an outflow rate of the
refrigerant flowing from the outdoor heat exchanger, and the
outflow rate adjustment valve may decrease the outflow rate of the
refrigerant in the defrosting operation as compared to before
transfer to the defrosting operation.
[0025] Furthermore, as in a sixth exemplar of the present
invention, the outflow rate adjustment valve may be configured
integrally with an outlet for the refrigerant of the outdoor heat
exchanger. Thus, a refrigerant passage volume from a discharge port
side of the compressor to an inlet side of the outflow rate
adjustment valve can be reduced, thereby reducing a refrigerant
flow amount flowing into the outdoor heat exchanger.
[0026] According to a seventh exemplar of the present invention,
the heat pump cycle of any one of first to sixth exemplars further
includes an outdoor blower which blows outside air toward both the
outdoor heat exchanger and the heat-dissipation heat exchanger, and
the outdoor blower increases an air blowing capacity when the
compressor is stopped, as compared to before stopping the
compressor.
[0027] When the compressor is stopped, the blowing capacity of the
outdoor blower can be increased to thereby quickly increase the
temperature of the outdoor heat exchanger to the same level as the
outside air, which can further reduce the defrosting time. The term
"when a compressor is stopped" means that the compressor is stopped
not only during the defrosting operation, but also during the
normal operation.
[0028] In an eighth exemplar of the present invention, the heat
pump cycle according to any one of first to seventh exemplars is
configured such that, in the defrosting operation, a heating
capacity of the user-side heat exchanger for heating the heat
exchange fluid is decreased as compared to before transfer to the
defrosting operation.
[0029] Thus, the heating capacity of the user-side heat exchanger
for the heat exchange fluid is decreased, so that the amount of
heat absorbed from the refrigerant at the outdoor heat exchanger
can be reduced to promote the defrosting. Specific means for
decreasing the heating capacity of the user-side heat exchanger for
the heat exchange fluid may include the reduction of a flow rate of
refrigerant circulating through the cycle, and the reduction of a
refrigerant pressure at the user-side heat exchanger.
[0030] According to a ninth exemplar of the present invention, in
the heat pump cycle according to any one of the first to eighth
exemplars, the heat-absorption air passage and the heat-dissipation
air passage are configured such that volumes of the outside air
flowing into the heat-absorption air passage and the
heat-dissipation air passage are decreased in the defrosting
operation.
[0031] Thus, the heat pump cycle can suppress the absorption of the
heat transmitted to the outdoor heat exchanger via the outer fins,
in the outside air flowing through the heat-absorption air passage
and the heat-dissipation air passage during the defrosting
operation, and thus can more effectively use the heat supplied from
the external heat source to defrost the outdoor heat exchanger in
the defrosting operation.
[0032] Specifically, an outdoor blower may be provided for blowing
the outside air toward both the outdoor heat exchanger and the
heat-dissipation heat exchanger. During the defrosting operation,
the blowing capacity of the outdoor blower may be reduced to
thereby decrease the volume of outside air flowing into the
heat-absorption air passage and the heat-dissipation air
passage.
[0033] Further, a shutter device (passage interruption means) may
be provided for opening and closing an inflow route for allowing
the outside air to flow into the heat-absorption air passage and
the heat-dissipation air passage. During the defrosting operation,
the shutter device may decrease a passage area of the inlet route
of the outside air to thereby decrease the volume of outside air
flowing into the heat-absorption air passage and the
heat-dissipation air passage.
[0034] The term "decreasing the volume of outside air" means not
only decreasing the volume of air as compared to the present volume
of inflow air, but also setting the volume of air to zero (0) (that
is, not allowing the outside air to flow thereinto).
[0035] In a tenth exemplar of the present invention, the heat pump
cycle according to any one of first to ninth exemplars further
includes an outdoor blower which blows outside air toward both the
outdoor heat exchanger and the heat-dissipation heat exchanger. In
this case, the heat-dissipation heat exchanger is located on a
windward side in the flow direction of the outside air blown by the
outdoor blower with respect to the outdoor heat exchanger.
[0036] Because the outside air whose heat is absorbed by the
heat-dissipation heat exchanger flows into the outdoor heat
exchanger, the heat of the cooling fluid can be transferred to the
outdoor heat exchanger not only via the outer fins but also via
air. Thus, during at least the defrosting operation, the heat
supplied from the external heat source can be used more effectively
to defrost the outdoor heat exchanger.
[0037] In an 11th exemplar of the present invention, in the heat
pump cycle according to any one of first to tenth exemplars, at
least one of the refrigerant tubes is located between the cooling
fluid tubes, at least one of the cooling fluid tubes is located
between the refrigerant tubes, and at least one of the
heat-absorption air passage and the heat-dissipation air passage is
formed as one air passage.
[0038] Thus, as compared to the case where the heat-dissipation
heat exchanger and the outdoor heat exchanger are arranged in
series with respect to the flow direction of the outside air, the
cooling fluid tube and the refrigerant tube can be arranged close
to each other. In other words, the cooling fluid tube can be
positioned near frost formed in the refrigerant tube. Thus, during
the defrosting operation, the heat supplied from the external heat
source can be effectively transmitted to the outdoor heat exchanger
to perform the defrosting operation.
[0039] According to a 12th exemplar of the present invention, the
heat pump cycle of any one of first to 11th exemplars may be
applied to an air conditioner for a vehicle, and may include an
inside air temperature detection portion configured to detect an
inside air temperature of a vehicle interior, and a frost formation
determination portion configured to determine frost formation of
the outdoor heat exchanger. In this case, the heat exchange fluid
is air blown into the vehicle interior, the external heat source is
a vehicle-mounted device generating heat in operation, the cooling
fluid is a coolant for cooling the vehicle-mounted device, and the
cooling fluid circuit switching device performs switching to the
cooling fluid circuit for flowing the cooling fluid into the
heat-dissipation heat exchanger when the frost is determined to be
formed at the outdoor heat exchanger by the frost formation
determination portion and an inside air temperature of the vehicle
interior is equal to or more than a predetermined reference inside
air temperature.
[0040] With this arrangement, the frost formation is determined by
a frost formation determination portion, and when the temperature
of an inside air within a vehicle compartment is equal to or more
than a predetermined reference inside air temperature, the frosting
operation is started. After the inside air temperature of the
vehicle interior is warmed up to some degree, the defrosting
operation can be started. Thus, during the defrosting operation,
even in the use of means for decreasing the heating capacity of the
air in the user-side heat exchanger, the heat pump cycle can
prevent the passenger from feeling unsatisfied with heating.
[0041] According to a 13th exemplar of the present invention, the
heat pump cycle of any one of first to 12th exemplars may be
applied to an air conditioner for a vehicle. In this case, the heat
pump cycle further includes a frost formation determination portion
for determining frost formation of the outdoor heat exchanger.
Furthermore, the heat exchange fluid is air blown into the vehicle
interior, the external heat source is a vehicle-mounted device
generating heat in operation, the cooling fluid is a coolant for
cooling the vehicle-mounted device, the user-side heat exchanger is
disposed in a casing forming therein an air passage, and an
inside/outside air switching device for changing a ratio of
introduction of inside air to outside air to be introduced into the
casing is disposed in the casing. Furthermore, the cooling fluid
circuit switching device performs switching to the cooling fluid
circuit for flowing the cooling fluid to the heat-dissipation heat
exchanger when the frost is determined to be formed at the outdoor
heat exchanger by the frost formation determination portion, and
the inside/outside air switching device increases the ratio of
introduction of the inside air to the outside air as compared to
before transfer to the defrosting operation when the frost is
determined to be formed at the outdoor heat exchanger by the frost
formation determination portion.
[0042] Thus, even in the use of the means for decreasing the
heating capacity of air in the user-side heat exchanger during the
defrosting operation, the ratio of introduction of the volume of
inside air having a high temperature to that of outside air is
increased, which can prevent the passenger from feeling unsatisfied
with heating.
[0043] According to a 14th exemplar of the present invention, the
heat pump cycle of one of first to 13th exemplars is applied to an
air conditioner for a vehicle, and the heat pump cycle further
includes a frost formation determination portion configured to
determine frost formation of the outdoor heat exchanger. In this
case, the heat exchange fluid is air blown into the vehicle
interior, the external heat source is a vehicle-mounted device
generating heat in operation, the cooling fluid is a coolant for
cooling the vehicle-mounted device, the user-side heat exchanger is
disposed in a casing forming therein an air passage, an air outlet
mode switching device for switching among air outlet modes by
changing opening/closing states of air outlets for blowing the air
into the vehicle interior is disposed in the casing, at least a
foot air outlet for blowing the air to a foot of a passenger is
provided as the air outlet, the cooling fluid circuit switching
device performs switching to the cooling fluid circuit for flowing
the cooling fluid into the heat-dissipation heat exchanger when the
frost is determined to be formed at the outdoor heat exchanger by
the frost formation determination portion, and the air outlet mode
switching device performs switching to the air outlet mode for
blowing the air from the foot air outlet when the frost is
determined to be formed at the outdoor heat exchanger by the frost
formation determination portion.
[0044] Further, even in the use of the means for decreasing the
heating capacity of air in the user-side heat exchanger during the
defrosting operation, switching is performed to an air outlet mode
for blowing the air from a foot air outlet. For example, as
compared to the case where the air is blown toward the face of the
passenger, the heat pump cycle can prevent the passenger from
feeling unsatisfied with heating.
[0045] According to a 15th exemplar of the present invention, the
heat pump cycle of any one of first to 14th exemplars is applied to
an air conditioner for a vehicle, and the heat pump cycle further
includes a frost formation determination portion configured to
determine frost formation of the outdoor heat exchanger. In this
case, the heat exchange fluid is air blown into the vehicle
interior, the external heat source is a vehicle-mounted device
generating heat in operation, the cooling fluid is a coolant for
cooling the vehicle-mounted device, the user-side heat exchanger is
disposed in a casing for forming therein an air passage, a blower
for blowing air toward the vehicle interior is disposed in the
casing, the cooling fluid circuit switching device performs
switching to the cooling fluid circuit for flowing the cooling
fluid into the heat-dissipation heat exchanger when the frost is
determined to be formed at the outdoor heat exchanger by the frost
formation determination portion, and the blower decreases an air
blowing capacity as compared to before the determination of the
frost formation.
[0046] Moreover, even in the use of the means for decreasing the
heating capacity of air in the user-side heat exchanger during the
defrosting operation, blower decreases its blowing capacity, which
can prevent the passenger from feeling unsatisfied with
heating.
[0047] According to a 16th exemplar of the present invention, the
heat pump cycle of any one of first to 15th exemplars may be
applied to an air conditioner for a vehicle, and the heat pump
cycle may further include a frost formation determination portion
for determining frost formation of the outdoor heat exchanger. In
this case, the heat exchange fluid is air blown into the vehicle
interior, the external heat source may be a vehicle-mounted device
generating heat in operation, the cooling fluid may be a coolant
for cooling the vehicle-mounted device, the frost formation
determination portion may determines that the frost is formed at
the outdoor heat exchanger when a vehicle speed is equal to or less
than a predetermined reference speed and when a temperature of the
refrigerant on an outlet side of the outdoor heat exchanger is
equal to or less than 0.degree. C., and the cooling fluid circuit
switching device may perform switching to a cooling fluid circuit
for flowing the cooling fluid into the heat-dissipation heat
exchanger when the frost is determined to be formed at the outdoor
heat exchanger by the frost formation determination portion.
[0048] Specifically, when the frost is formed at the outdoor heat
exchanger, the heat contained in a vehicle-mounted device can be
effectively used to defrost the outdoor heat exchanger. Further, a
frost formation determination portion determines that the frost is
formed at the outdoor heat exchanger when the speed of the vehicle
is equal to or less than a predetermined reference vehicle speed
and the temperature of refrigerant on the outlet side of the
outdoor heat exchanger is equal to or less than 0.degree. C. In
this way, the appropriate determination of frost formation is
performed taking into consideration the vehicle speed.
[0049] According to a 17th exemplar of the present invention, in
the heat pump cycle according to 16th exemplar, the frost formation
determination portion may determine that the frost is formed at the
outdoor heat exchanger, when the speed of the traveling vehicle is
equal to or less than the predetermined reference speed, and when
the temperature of the refrigerant on the outlet side of the
outdoor heat exchanger is equal to or less than 0.degree. C. The
term "traveling vehicle" means that a vehicle whose speed is zero,
that is, a stopping vehicle is not included.
[0050] According to an 18th exemplar of the present invention, the
heat pump cycle of one of exemplars 12 to 17 further includes a
coolant temperature detection portion configured to detect a
temperature of the coolant flowing into a vehicle-mounted device.
In this case, the cooling fluid circuit switching device performs
switching to the cooling fluid circuit for flowing the cooling
fluid into the heat-dissipation heat exchanger when a coolant
temperature detected by the coolant temperature detection portion
is equal to or more than the predetermined reference
temperature.
[0051] In this way, heat contained in the coolant is dissipated
from the heat-dissipation heat exchanger, which can protect the
vehicle-mounted device from overheat. The heat dissipated from the
heat-dissipation heat exchanger can be transferred to the outdoor
heat exchanger, and then absorbed in the refrigerant. In the normal
operation of the heat pump cycle, the indoor air can be effectively
heated. As a result, the heating performance of the air conditioner
for the vehicle can be improved.
[0052] According to a 19th example of the present invention, in the
heat pump cycle of any one of first to 18th exemplars, the cooling
fluid circulation circuit stores therein the heat contained in the
external heat source when the cooling fluid circuit switching
device performs switching to the cooling fluid circuit for allowing
the cooling fluid to bypass the heat-dissipation heat
exchanger.
[0053] Thus, when the defrosting operation is not necessary, the
cooling fluid circuit switching device performs switching to a
cooling fluid circuit for allowing the flow of the cooling fluid to
bypass the heat-dissipation heat exchanger, which can store the
heat contained in the external heat source, in the heat pump cycle.
As a result, the heat stored during the defrosting operation can be
used to complete the defrosting in a short time.
[0054] For example, according to a 20th exemplar of the present
invention, the heat pump cycle of the 19th exemplar is applied to
an air conditioner for a vehicle. In this case, the heat exchange
fluid may be air blown into the vehicle interior, the external heat
source may be a vehicle-mounted device generating heat in
operation, the cooling fluid may be a coolant for cooling the
vehicle-mounted device, and the cooling fluid circulation circuit
may store heat dissipated from the vehicle-mounted device in the
coolant when the cooling fluid circuit switching device performs
switching to the cooling fluid circuit for allowing the cooling
fluid to bypass the heat-dissipation heat exchanger.
[0055] According to a 21st exemplar of the present invention, the
heat pump cycle of 19th exemplar is applied to an air conditioner
for a vehicle. In this case, the heat exchange fluid may be air
blown into the vehicle interior, the external heat source may be a
heating element for generating heat by being supplied with power,
the cooling fluid may be a coolant for cooling the heating element,
and the cooling fluid circulation circuit may store the heat
dissipated from the heating element in the coolant when the cooling
fluid circuit switching device performs switching to the cooling
fluid circuit for allowing the cooling fluid to bypass the
heat-dissipation heat exchanger.
[0056] According to a 22nd exemplar of the present invention, the
heat pump cycle of 21st exemplar is applied to an air conditioner
for a vehicle. In this case, the heat exchange fluid may be air
blown into the vehicle interior, a vehicle-mounted device
generating heat in operation and a heating element for generating
heat by being supplied with power may be provided as the external
heat source, the cooling fluid may be a coolant for cooling the
heating element and the vehicle-mounted device, and the cooling
fluid circulation circuit may store the heat dissipated from at
least one of the vehicle-mounted device and the heating element in
the coolant when the cooling fluid circuit switching device
performs switching to the cooling fluid circuit for allowing the
cooling fluid to bypass the heat-dissipation heat exchanger.
[0057] Furthermore, as in a 23rd exemplar of the present invention,
the heating element may be an amount of generated heat therefrom
controlled based on an outside air temperature. Therefore, it can
restrict unnecessary electrical power from being consumed in the
heating element.
[0058] According to a 24th exemplar of the present invention, the
heat pump cycle may further include: an outdoor unit bypass passage
which causes the refrigerant decompressed by the decompression
device to bypass the outdoor heat exchanger and to guide the
refrigerant to a refrigerant outlet side of the outdoor heat
exchanger; and an outdoor-unit bypass passage switching device
configured to switch between a refrigerant circuit for guiding the
refrigerant decompressed by the decompression device to the outdoor
heat exchanger, and a refrigerant circuit for guiding the
refrigerant decompressed by the decompression device toward the
outdoor unit bypass passage. In this case, in the defrosting
operation, the outdoor unit bypass passage switching device
performs switching to the refrigerant circuit for guiding the
refrigerant decompressed by the decompression device to the outdoor
unit bypass passage.
[0059] The outdoor unit bypass passage switching device performs
switching to a refrigerant circuit for guiding the refrigerant
decompressed by decompression device to an outdoor unit bypass
passage in the defrosting operation, which can prevent the heat
transmitted to the outdoor unit heat exchanger via the outer fins
from being absorbed in the refrigerant flowing through the outdoor
heat exchanger during the defrosting operation.
[0060] Accordingly, the heat supplied from the external heat source
can be used more effectively to defrost the outdoor heat exchanger
during the defrosting operation. For example, in application to an
air conditioner for a vehicle, the air can be heated by the
user-side heat exchanger to achieve the heating of the vehicle
interior.
[0061] According to a 25th exemplar of the present invention, the
heat pump cycle may further include: an indoor evaporator which
exchanges heat between the refrigerant on a downstream side of the
outdoor heat exchanger and the heat exchange fluid; an evaporator
bypass passage which causes the refrigerant on the downstream side
of the outdoor heat exchanger to bypass the indoor evaporator and
to guide the refrigerant to a refrigerant outlet of the indoor
evaporator; and an evaporator bypass passage switching device
configured to switch a refrigerant circuit for guiding the
refrigerant on the downstream side of the outdoor heat exchanger to
the indoor evaporator, and a refrigerant circuit for guiding the
refrigerant on the downstream side of the outdoor heat exchanger to
the evaporator bypass passage. In the defrosting operation, the
evaporator bypass passage switching device performs switching to
the refrigerant circuit for guiding the refrigerant on the
downstream side of the outdoor heat exchanger to the indoor
evaporator.
[0062] Thus, during the defrosting operation, the evaporator bypass
passage switching device guides the refrigerant on the downstream
side of the outdoor heat exchanger to an indoor evaporator side, so
that the indoor evaporator can cool the heat exchange fluid by a
heat absorption effect when the refrigerant is evaporated. For
example, in application to the air conditioner for a vehicle, a
dehumidification heating operation can be achieved in which the air
cooled by the indoor evaporator is heated again by the user-side
heat exchanger.
[0063] According to a 26th exemplar of the present invention, the
heat pump cycle may be applied to an air conditioner for a vehicle.
In this case, the heat exchange fluid is air blown into the vehicle
interior, the user-side heat exchanger is disposed in a casing for
forming therein an air blowing passage, and in the casing, an
auxiliary heater is provided for heating the air blown into the
vehicle interior using as a heating source, at least one of a
heating fluid heated by a vehicle-mounted device that generates
heat in operation, and a heating element that generates heat by
being supplied with power.
[0064] Thus, even when the heating capacity of the user-side heat
exchanger for the air is reduced by decreasing the refrigerant
discharge capacity of the compressor during the defrosting
operation, the air can be heated by an auxiliary heater. This
arrangement can suppress the reduction in temperature of the air
blown into the vehicle interior and thus can prevent the passenger
from feeling unsatisfied with heating.
BRIEF DESCRIPTION OF THE DRAWINGS
[0065] FIG. 1 is an overall schematic diagram showing refrigerant
flow in a heating operation of a heat pump cycle according to a
first embodiment.
[0066] FIG. 2 is an overall schematic diagram showing refrigerant
flow in a defrosting operation of the heat pump cycle according to
the first embodiment.
[0067] FIG. 3 is an overall schematic diagram showing refrigerant
flow in a waste heat collecting operation of the heat pump cycle
according to the first embodiment.
[0068] FIG. 4 is an overall schematic diagram showing refrigerant
flow in a cooling operation of the heat pump cycle according to the
first embodiment.
[0069] FIG. 5 is a schematic diagram showing a detail structure of
an indoor air conditioning unit according to the first
embodiment.
[0070] FIG. 6 is an overall schematic diagram showing refrigerant
flow in a heating operation of a heat pump cycle according to a
second embodiment.
[0071] FIG. 7 is an overall schematic diagram showing refrigerant
flow in a defrosting operation of a heat pump cycle according to a
third embodiment.
[0072] FIG. 8 is an overall schematic diagram showing refrigerant
flow in a defrosting operation of a heat pump cycle according to a
fourth embodiment.
[0073] FIG. 9 is an overall schematic diagram showing refrigerant
flow in a defrosting operation of a heat pump cycle according to a
fifth embodiment.
[0074] FIG. 10 is a perspective view of a heat exchanger structure
according to a sixth embodiment.
[0075] FIG. 11 is an exploded perspective view of the heat
exchanger structure according to the sixth embodiment.
[0076] FIG. 12 is a cross-sectional view taken along the line A-A
in FIG. 10.
[0077] FIG. 13 is an exemplary perspective view for explaining the
flow of refrigerant and the flow of coolant in the heat exchanger
structure according to the sixth embodiment.
[0078] FIG. 14 is a flowchart showing a control flow of a vehicle
interior linkage control according to a seventh embodiment.
[0079] FIG. 15 is a flowchart showing another control flow of the
vehicle interior linkage control according to the seventh
embodiment.
[0080] FIG. 16 is a flowchart showing another control flow of the
vehicle interior linkage control according to the seventh
embodiment.
[0081] FIG. 17 is a flowchart showing another control flow of the
vehicle interior linkage control according to the seventh
embodiment.
[0082] FIG. 18 is an overall schematic diagram showing refrigerant
flow in a defrosting operation of a heat pump cycle according to an
eighth embodiment.
[0083] FIG. 19 is an overall schematic diagram showing refrigerant
flow in a defrosting operation of a heat pump cycle according to a
ninth embodiment.
[0084] FIG. 20 is an overall schematic diagram showing refrigerant
flow in a defrosting operation of a heat pump cycle according to a
tenth embodiment.
[0085] FIG. 21 is an overall schematic diagram showing refrigerant
flow in a defrosting operation of a heat pump cycle according to an
eleventh embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
[0086] Referring to FIGS. 1 to 5, a first embodiment of the present
invention will be described below. In this embodiment of the
present invention, a heat pump cycle 10 is applied to an air
conditioner 1 for a vehicle of the so-called hybrid car, which can
obtain a driving force for traveling from an internal combustion
engine (engine) and an electric motor MG for traveling. FIG. 1
shows an entire configuration diagram of the air conditioner 1 for
the vehicle of this embodiment.
[0087] The hybrid car can perform switching between a traveling
state in which the vehicle travels obtaining the driving force from
both engine and electric motor MG for traveling by operating or
stopping the engine according to a traveling load on the vehicle or
the like, and another traveling state in which the vehicle travels
obtaining the driving force only from the electric motor MG for
traveling by stopping the engine. Thus, the hybrid car can improve
the fuel efficiency as compared to normal cars obtaining a driving
force for traveling only from the engine.
[0088] The heat pump cycle 10 in the air conditioner 1 for the
vehicle serves to heat or cool the air in the vehicle compartment
to be blown into the vehicle interior as a space for air
conditioning. Thus, the heat pump cycle 10 can switch between
refrigerant flow paths to thereby perform a heating operation
(heater operation) and a cooling operation (cooler operation). The
heating operation is adapted to heat the vehicle interior by
heating the air in the vehicle compartment as a heat exchange fluid
as a normal operation. The cooling operation is adapted to cool the
vehicle interior by cooling the air blown into the vehicle
compartment.
[0089] Then, the heat pump cycle 10 can also perform a defrosting
operation for melting and removing frost formed at an outdoor heat
exchanger 16 serving as an evaporator for evaporating refrigerant
in the heating operation, and a waste heat collecting operation for
absorbing heat contained in the electric motor MG for traveling as
the external heat source, in the refrigerant in the heating
operation. In the entire configuration diagrams of the heat pump
cycle 10 shown in FIGS. 1 to 4, the flow of refrigerant in each
operation is designated by a solid arrow.
[0090] The heat pump cycle 10 of this embodiment employs a normal
flon-based refrigerant as a refrigerant, and forms a subcritical
refrigeration cycle whose high-pressure side refrigerant pressure
does not exceed the critical pressure of the refrigerant. Into the
refrigerant, a refrigerant oil for lubricating a compressor 11 is
mixed, and a part of the refrigerant oil circulates through the
cycle together with the refrigerant.
[0091] First, the compressor 11 is positioned in an engine room,
and is to suck, compress, and discharge the refrigerant in the heat
pump cycle 10. The compressor is an electric compressor which
drives a fixed displacement compressor 11a having a fixed discharge
capacity by use of an electric motor 11b. Specifically, various
types of compression mechanisms, such as a scroll type compression
mechanism, or a vane compression mechanism, can be employed as the
fixed displacement compressor 11a.
[0092] The electric motor 11b is one whose operation (number of
revolutions) is controlled by a control signal output from an air
conditioning controller to be described later. The motor 11b may
use either an AC motor or a DC motor. The control of the number of
revolutions of the motor changes a refrigerant discharge capacity
of the compression mechanism 11. Thus, in this embodiment, the
electric motor 11b serves as a discharge capacity changing portion
of the compressor 11.
[0093] A refrigerant discharge port of the compressor 11 is coupled
to a refrigerant inlet side of an indoor condenser 12 as a
user-side heat exchanger. The indoor condenser 12 is disposed in a
casing 31 of an indoor air conditioning unit 30 of the air
conditioner 1 for the vehicle. The indoor condenser 12 is a heat
exchanger for heating that exchanges heat between a
high-temperature and high-pressure refrigerant flowing therethrough
and the air to be blown into the vehicle compartment and having
passed through an indoor evaporator 20 described later. The
detailed structure of the indoor air conditioning unit 30 will be
described later.
[0094] A fixed throttle 13 for heating is coupled to a refrigerant
outlet side of the indoor condenser 12. The fixed throttle 13
serves as a decompression device for the heating operation that
decompresses and expands the refrigerant flowing from the indoor
condenser 12 in the heating operation. The fixed throttle 13 for
heating can use an orifice, a capillary tube, and the like. The
outlet side of the fixed throttle 13 for heating is coupled to the
refrigerant inlet side of the outdoor heat exchanger 16.
[0095] A bypass passage 14 for the fixed throttle 13 is coupled to
the refrigerant outlet side of the indoor condenser 12. The bypass
passage 14 causes a refrigerant flowing from the indoor condenser
12 to bypass the fixed throttle 13 for heating and guides the
refrigerant into the outdoor heat exchanger 16. An opening/closing
valve 15a for opening and closing the bypass passage 14 for the
fixed throttle is disposed in the bypass passage 14 for the fixed
throttle. The opening/closing valve 15a is an electromagnetic valve
whose opening and closing operations are controlled by a control
voltage output from the air conditioning controller.
[0096] The loss in pressure caused when the refrigerant passes
through the opening/closing valve 15a is extremely small as
compared to the loss caused in pressure when the refrigerant passes
through the fixed throttle 13. Thus, when the opening/closing valve
15a is opened, the refrigerant flowing out of the indoor condenser
12 flows into the outdoor heat exchanger 16 via the bypass passage
14 for the fixed throttle. In contrast, when the opening/closing
valve 15a is closed, the refrigerant flows into the outdoor heat
exchanger 16 via the fixed throttle 13 for heating.
[0097] Thus, the opening/closing valve 15a can switch between the
refrigerant flow paths of the heat pump cycle 10. The
opening/closing valve 15a of this embodiment serves as a
refrigerant flow path switching device. Alternatively, as such a
refrigerant flow path switching device, an electric three-way valve
or the like may be provided for switching between a refrigerant
circuit for coupling the outlet side of the indoor condenser 12 to
the inlet side of the fixed throttle 13 for heating, and another
refrigerant circuit for coupling the outlet side of the indoor
condenser 12 and the inlet side of the bypass passage 14 for the
fixed throttle.
[0098] The outdoor heat exchanger 16 is to exchange heat between
the low-pressure refrigerant flowing therethrough and an outside
air blown from a blower fan 17. The outdoor heat exchanger 16 is a
heat exchanger disposed in an engine room, and which serves as an
evaporator for evaporating the low-pressure refrigerant to exhibit
a heat absorption effect in the heating operation, and also as a
radiator for dissipating heat from the high-pressure refrigerant in
the cooling operation.
[0099] The blower fan 17 is an electric blower whose operating
ratio, that is, whose number of revolutions (volume of air) is
controlled by a control voltage output from the air conditioning
controller. The outdoor heat exchanger 16 of this embodiment is
integral with a radiator 43 to be described later, for exchanging
heat between the coolant for cooling the electric motor MG for
traveling and the outside air blown from the blower fan 17.
[0100] The blower fan 17 of this embodiment serves as an outdoor
blower for blowing the outside air toward both the outdoor heat
exchanger 16 and the radiator 43. The detailed structures of the
outdoor heat exchanger 16 and the radiator 43 (hereinafter referred
to as a "heat exchanger structure 70") which are integral with each
other will be described in detail below.
[0101] The outlet side of the outdoor heat exchanger 16 is coupled
to an electric three-way valve 15b. The three-way valve 15b has its
operation controlled by a control voltage output from the air
conditioning controller. The three-way valve 15b serves as the
refrigerant flow path switching device together with the above
opening/closing valve 15a.
[0102] More specifically, in the heating operation, the three-way
valve 15b performs switching to the refrigerant flow path for
coupling the outlet side of the outdoor heat exchanger 19 to the
inlet side of an accumulator 18 to be described later. In contrast,
in the cooling operation, the three-way valve 15b performs
switching to the refrigerant flow path for coupling the outlet side
of the outdoor heat exchanger 16 to the inlet side of a fixed
throttle 19 for cooling.
[0103] The fixed throttle 19 for cooling serves as decompression
device for the cooler operation (cooling operation) for
decompressing and expanding the refrigerant flowing from the
outdoor heat exchanger 16 in the cooling operation. The fixed
throttle 19 has the same basic structure as that of the above fixed
throttle 13 for heating. The outlet side of the fixed throttle 19
for cooling is coupled to the refrigerant inlet side of an indoor
evaporator 20.
[0104] The indoor evaporator 20 is disposed on the upstream side of
the air flow with respect to the indoor condenser 12 in the casing
31 of the indoor air conditioning unit 30. The indoor evaporator 20
is a heat exchanger for cooling that exchanges heat between the
vehicle indoor air and the refrigerant flowing therethrough to
thereby cool the air within the vehicle interior. A refrigerant
outlet side of the indoor evaporator 20 is coupled to an inlet side
of the accumulator 18.
[0105] Thus, a refrigerant flow path for allowing the refrigerant
to flow from the three-way valve 15b to the inlet side of the
accumulator 18 in the heating operation serves as an evaporator
bypass passage 20a for allowing the refrigerant on the downstream
side of the outdoor heat exchanger 16 to bypass the indoor
evaporator 20. The three-way valve 15b serves as evaporator bypass
passage switching device for switching between a refrigerant
circuit for guiding the refrigerant on the downstream side of the
outdoor heat exchanger 16 to the indoor evaporator 20, and another
refrigerant circuit for guiding the refrigerant on the downstream
side of the outdoor heat exchanger 16 to the evaporator bypass
passage 20a.
[0106] The accumulator 18 is a gas-liquid separator for the
low-pressure side refrigerant that separates the refrigerant
flowing thereinto into liquid and gas phases, and which stores
therein the excessive refrigerant within the cycle. A vapor-phase
refrigerant outlet of the accumulator 18 is coupled to a suction
side of the compressor 11. Thus, the accumulator 18 serves to
suppress the suction of the liquid-phase refrigerant into the
compressor 11 to thereby prevent the compression of the liquid in
the compressor 11.
[0107] Next, the indoor air conditioning unit 30 will be described
below using FIG. 5. FIG. 5 shows an enlarged detailed configuration
diagram, representing the indoor air conditioning unit 30 shown in
FIGS. 1 to 4. The indoor air conditioning unit 30 is disposed
inside a gauge board (instrument panel) at the forefront of the
vehicle compartment. The unit 30 accommodates in a casing 31
serving as an outer envelope, a blower 32, the above-mentioned
indoor condenser 12, and the indoor evaporator 20.
[0108] The casing 31 forms an air passage communicating with the
vehicle compartment, through which air is blown into the vehicle
interior. The casing 31 is formed of resin (for example,
polypropylene) having some degree of elasticity, and excellent
strength. An inside/outside air switch 33 for switching between the
air (inside air) in the vehicle interior and the outside air to
introduce the selected air is disposed on the most upstream side of
the vehicle-interior air flow in the casing 31.
[0109] The inside/outside air switch 33 is an inside/outside air
switching device for switching between suction port modes by
continuously adjusting the opening areas of an inside air inlet for
introducing the inside air into the casing 31 and an outside air
inlet for introducing the outside air thereinto by an
inside/outside air switching door to thereby continuously change
the ratio of introduction of the inside air to the outside air.
[0110] The inside/outside air switch 33 is provided with the inside
air inlet for introducing the inside air into the casing 31, and
the outside air inlet for introducing the outside air thereinto.
The inside/outside air switching door is positioned inside the
inside/outside air switch 33 to continuously adjust the opening
areas of the inside air inlet and the outside air inlet to thereby
change the ratio of volume of the inside air to that of the outside
air. The inside/outside air switching door is driven by an electric
actuator (not shown) whose operation is controlled by a control
signal output from an air conditioning controller.
[0111] The suction port modes switched by the inside/outside air
switch 33 includes an inside air mode for introducing the inside
air into the casing 31 by fully opening the inside air inlet, while
completely closing the outside air inlet; an outside air mode for
introducing the outside air into the casing 31, while completely
closing the inside air inlet and fully opening the outside air
inlet; and an inside-outside air mixing mode for simultaneously
opening the inside air inlet and the outside air inlet.
[0112] A blower 32 for blowing the air sucked via the
inside/outside air switch 33 into the vehicle interior is disposed
on the downstream side of the air flow of the inside/outside air
switch 33. The blower 32 is an electric blower which includes a
centrifugal multiblade fan (sirocco fan) driven by an electric
motor, and whose number of revolutions (volume of air) is
controlled by a control voltage output from the air conditioning
controller.
[0113] The indoor evaporator 20 and the indoor condenser 12 are
disposed on the downstream side of the air flow of the blower 32,
in that order with respect to the flow of the air in the vehicle
interior. In short, the indoor evaporator 20 is disposed on the
upstream side in the flow direction of the vehicle indoor air with
respect to the indoor condenser 12.
[0114] An air mix door 34 is disposed on the downstream side of the
air flow in the indoor evaporator 20 and on the upstream side of
the air flow in the indoor condenser 12. The air mix door 34
adjusts the rate of volume of the air passing through the indoor
condenser 12 among the air passing through the indoor evaporator
20. A mixing space 35 is provided on the downstream side of the air
flow in the indoor condenser 12 so as to mix the air exchanging
heat with the refrigerant and being heated at the indoor condenser
12 and the air bypassing the indoor condenser 12 and not being
heated.
[0115] An opening hole for blowing the conditioned air mixed in the
mixing space 35, into the vehicle interior as a space of interest
to be cooled is disposed on the most downstream side of the air
flow in the casing 31. Specifically, the opening holes include a
defroster opening hole 36a for blowing the conditioned air toward
the inner side of a front glass of the vehicle, a face opening hole
36b for blowing the conditioned air toward the upper body of a
passenger in the vehicle compartment, and a foot opening hole 36c
for blowing the conditioned air toward the foot of the
passenger.
[0116] The defroster opening hole 36a, the face opening hole 36b,
and the foot opening hole 36c have the respective downstream sides
of the air flows thereof connected to a defroster air outlet, a
face air outlet, and a foot air outlet provided in the vehicle
compartment via ducts forming respective air passages.
[0117] The air mix door 34 adjusts the rate of volume of air
passing through the indoor condenser 12 to thereby adjust the
temperature of conditioned air mixed in the mixing space 35, thus
controlling the temperature of the conditioned air blown from each
air outlet. That is, the air mix door 34 serves as a temperature
adjustment device for adjusting the temperature of the conditioned
air blown into the vehicle interior.
[0118] In short, the air mix door 34 serves as heat exchanging
amount adjustment device for adjusting the amount of heat exchanged
between the refrigerant discharged from the compressor 11 and the
air in the vehicle interior in the indoor condenser 12 serving as
the user-side heat exchanger. The air mix door 34 is driven by a
servo motor (not shown) whose operation is controlled based on the
control signal output from the air conditioning controller.
[0119] The defroster opening hole 36a, the face opening hole 36b,
and the foot opening hole 36c have, at the respective upstream
sides of the air flows thereof, a defroster door 37a for adjusting
an opening area of the defroster opening hole 36a, a face door 37b
for adjusting an opening area of the face opening hole 36b, and a
foot door 37c for adjusting an opening area of the foot opening
hole 36c, respectively.
[0120] The defroster door 37a, the face door 37b, and the foot door
37c serve as air outlet mode changing device for changing the
opening/closing state of each air outlet for blowing the air into
the vehicle interior, and are driven by an electric actuator (not
shown) whose operation is controlled based on a control signal
output from the air conditioning controller.
[0121] The air outlet modes include a face mode for blowing air
toward the upper half body of the passenger in the vehicle interior
from the face air outlet by fully opening the face air outlet, a
bi-level mode for blowing air toward the upper half body and the
foot of the passenger in the vehicle interior by opening both the
face air outlet and the foot air outlet, and a foot mode for
blowing air mainly from the foot air outlet by fully opening the
foot air outlet, while slightly opening the defroster air
outlet.
[0122] The passenger can manually operate switches on an operation
panel to be described later to thereby setting the defroster mode
for blowing the air from the defroster air outlet toward the inner
surface of the front glass of the vehicle by fully opening the
defroster air outlet.
[0123] Next, a coolant circulation circuit 40 will be described
below. The coolant circulation circuit 40 is a cooling fluid
circulation circuit for cooling the electric motor MG for traveling
by allowing the coolant (for example, ethylene glycol aqueous
solution) as a cooling fluid to circulate through a coolant passage
formed in the above electric motor MG for traveling, which is one
of the vehicle-mounted devices generating heat in operation.
[0124] The coolant circulation circuit 40 is provided with a
coolant pump 41, an electric three-way valve 42, the radiator 43,
and a bypass passage 44 for allowing the coolant to flow bypassing
the radiator 43.
[0125] The coolant pump 41 is an electric pump for squeezing the
coolant into a coolant passage formed within the electric motor MG
for traveling in the coolant circulation circuit 40, and whose
number of revolutions (flow rate) is controlled by a control signal
output from the air conditioning controller. Thus, the coolant pump
41 serves as a cooling capacity adjustment portion for adjusting
the cooling capacity by changing the flow rate of the coolant for
cooling the electric motor MG for traveling.
[0126] A three-way valve 42 switches between a cooling fluid
circuit for flowing the coolant into the radiator 43 by connecting
the inlet side of the coolant pump 41 to the outlet side of the
radiator 43, and another cooling fluid circuit for flowing the
coolant to bypass the radiator 43 by connecting the inlet side of
the coolant pump 41 to the outlet side of a bypass passage 44. The
three-way valve 42 whose operation is controlled by the control
voltage output from the air conditioning controller serves as
cooling fluid circuit switching device.
[0127] That is, as illustrated by a dashed arrow of FIG. 1 or the
like, the coolant circulation circuit 40 of this embodiment can
perform switching between the cooling fluid circuit for circulation
of the coolant from the coolant pump 41, the electric motor MG for
traveling, the radiator 43, and the cooling pump 41 in that order,
and the cooling fluid circuit for circulation of the coolant from
the coolant pump 41, the electric motor MG for traveling, the
bypass passage 44, and the coolant pump 41 in that order.
[0128] Thus, when the three-way valve 42 performs switching to the
cooling fluid circuit for allowing the coolant to bypass the
radiator 43 during the operation of the electric motor MG for
traveling, the coolant has its temperature increased without
dissipating its heat into the radiator 43. That is, when the
three-way valve 42 performs switching to the cooling fluid circuit
for allowing the coolant to bypass the radiator 43, the heat (heat
generated) contained in the electric motor MG for traveling is
stored in the coolant.
[0129] The radiator 43 is a heat-dissipation heat exchanger that is
disposed in an engine room, and which exchanges heat between the
coolant and the outside air blown from the blower fan 17. As
mentioned above, the radiator 43 is integrally structured with the
outdoor heat exchanger 16 to form a heat exchanger structure
70.
[0130] Now, the details of the heat exchanger structure 70 will be
described below. Each of the outdoor heat exchanger 16 and the
radiator 43 in this embodiment is comprised of the so-called tank
and tube heat exchanger which includes a plurality of tubes for
allowing the refrigerant or coolant to flow therethrough, and a
pair of tanks for collection and distribution which are positioned
on both sides of the tubes and which are designed to collect or
distribute the refrigerant or coolant flowing through the
tubes.
[0131] More specifically, the outdoor heat exchanger 16 includes a
plurality of the refrigerant tubes 16a for flowing the refrigerant
therethrough. Further, the refrigerant tube 16a is a flat tube
having a flattened cross section in the direction perpendicular to
the longitudinal direction. The respective the refrigerant tubes
16a are laminated with a predetermined gap therebetween such that
flat surfaces of the outer surfaces thereof are opposed to each
other in parallel.
[0132] Thus, a heat-absorption air passage 16b to flow the outside
air blown from the blower fan 17 is formed around the refrigerant
tubes 16a, that is, between the adjacent the refrigerant tubes
16a.
[0133] The radiator 43 includes a plurality of cooling fluid tubes
43a for allowing the coolant to flow therethrough, and having a
flattened cross section in the direction perpendicular to the
longitudinal direction. Like the refrigerant tubes 16a, the cooling
fluid tubes 43a are laminated with a predetermined gap
therebetween. A heat-dissipation air passage 43b to flow the
outside air blown from the blower fan 17 is formed around the
cooling fluid tubes 43a, that is, between the adjacent cooling
fluid tubes 43a.
[0134] In this embodiment, the respective tanks for collection and
distribution of the outdoor heat exchanger 16 and the radiator 43
are partially made of the same material, and the heat-absorption
air passage and the heat-dissipation air passage are provided with
outer fins 50 made of the same substance. The outer fins 50 are
bonded to both tubes 16a and 43a, so that the outdoor heat
exchanger 16 and the radiator 43 are integral with each other to
form the heat exchanger structure 70.
[0135] The outer fin 50 in use is a corrugated fin formed by
bending a thin metal plate with excellent heat conductivity in a
wave shape. A part of the outer fin 50 disposed in the
heat-absorption air passage serves to promote the heat exchange
between the refrigerant and the outside air, and another part
thereof disposed in the heat-dissipation air passage serves to
promote the heat exchange between the coolant and the outside
air.
[0136] Further, each outer fin 50 is bonded to both the refrigerant
tube 16a and the cooling fluid tube 43a, which enables the heat
transfer between the refrigerant tubes 16a and the cooling fluid
tubes 43a.
[0137] In this embodiment described above, the refrigerant tubes
16a of the outdoor heat exchanger 16, the cooling fluid tubes 43a
of the radiator 43, the tanks for collection and distribution, and
the outer fins 50 are all formed of an aluminum alloy, and integral
with one another by brazing. Further, in this embodiment, the
radiator 43 is integral with the outdoor heat exchanger 16 on the
windward side in the flow direction X of the outside air blown by
the blower fan 17.
[0138] Now, an electric control unit of this embodiment will be
described below. The air conditioning controller is comprised of
the known microcomputer including a CPU, an ROM, and an RAM, and
peripheral circuits thereof. The control unit controls the
operation of each of the air conditioning controller 11, 15a, 15b,
17, 41, and 42 connected to its output by executing various
operations and processing based on air conditioning control
programs stored in the ROM.
[0139] A group of various sensors for control of air conditioning
is coupled to the input side of the air conditioning controller.
The sensors include an inside air sensor serving as inside air
temperature detection portion for detecting a temperature of the
vehicle interior, an outside air sensor for detecting a temperature
of the outside air, a solar radiation sensor for detecting an
amount of solar radiation in the vehicle interior, and an
evaporator temperature sensor for detecting a temperature of blown
air from the indoor evaporator 20 (evaporator temperature). And,
the sensors also include a discharged refrigerant temperature
sensor for detecting a temperature of the refrigerant discharged
from the compressor 11, an outlet refrigerant temperature sensor 51
for detecting a refrigerant temperature Te on the outlet side of
the outdoor heat exchanger 16, and a coolant temperature sensor 52
serving as coolant temperature detection portion for detecting a
coolant temperature Tw of the coolant flowing into the electric
motor MG for traveling.
[0140] In this embodiment, the coolant temperature sensor 51
detects the coolant temperature Tw of the coolant squeezed from the
coolant pump 41. Alternatively, the coolant temperature Tw of the
coolant sucked into the coolant pump 41 may be detected.
[0141] An operation panel (not shown) disposed near an instrument
board at the front of the vehicle compartment is connected to the
input side of the air conditioning controller. Operation signals
are input from various types of air conditioning operation switches
provided on the operation panel. Various air conditioning operation
switches provided on the panel include an operation switch for the
air conditioner for the vehicle, a vehicle-interior temperature
setting switch for setting the temperature of the vehicle interior,
and a selection switch for selecting an operation mode.
[0142] The air conditioning controller includes a control portion
for controlling the electric motor 11b for the compressor 11, and
the opening/closing valve 15a and the like which are integral with
each other, and is designed to control the operations of these
components. In the air conditioning controller of this embodiment,
the structure (hardware and software) for controlling the operation
of the compressor 11 serves as a refrigerant discharge capacity
control portion. The structure for controlling the operations of
the respective devices 15a and 15b serving as the refrigerant flow
path switching device serves as a refrigerant flow path control
portion. The structure for controlling the operation of the
three-way valve 42 serving as the cooling fluid circuit switching
device for coolant serves as a cooling fluid circuit control
portion.
[0143] The air conditioning controller of this embodiment includes
the structure (a frost formation determination portion) for
determining whether or not the frost is formed at the outdoor heat
exchanger 16, based on a detection signal from the above sensor
group for the air conditioning control. Specifically, when the
speed of a traveling vehicle is equal to or less than a
predetermined reference value (in this embodiment, 20 km/h), and
the refrigerant temperature Te on the outlet side of the outdoor
heat exchanger 16 is equal to or less than 0.degree. C., the frost
formation determination portion of this embodiment determines that
the frost formation is caused at the outdoor heat exchanger 16.
[0144] The determination using the frost formation determination
portion is not limited thereto. Alternatively, for example, when
the vehicle is stopped (specifically, the vehicle speed=0 km/h)
with a vehicle system kept in operation, and the refrigerant
temperature Te on the outlet side of the outdoor heat exchanger 16
is equal to or less than 0.degree. C., the frost formation may be
determined to be caused at the outdoor heat exchanger 16.
[0145] Next, the operation of the air conditioner 1 for the vehicle
with the above arrangement in this embodiment will be described
below. The air conditioner 1 for the vehicle of this embodiment can
execute a heating operation for heating the vehicle interior, and a
cooling operation for cooling the vehicle interior. In the heating
operation, a defrosting operation and a waste heat collecting
operation can also be carried out. Now, each operation will be
explained in the following.
(a) Heating Operation
[0146] The heating operation is started when the heating operation
mode is selected by the selection switch with the operation switch
of the operation panel is turned on (ON). Then, in the heating
operation, when the frost formation determination portion
determines that the frost is formed at the outdoor heat exchanger
16, the defrosting operation is performed. When the coolant
temperature Tw detected by the coolant temperature sensor 52 is
equal to or more than the predetermined reference temperature (in
this embodiment, 60.degree. C.), the waste heat collecting
operation is performed.
[0147] In the normal heating operation, the air conditioning
controller closes the opening/closing valve 15a, and switches the
three-way valve 15b to the refrigerant flow path for coupling the
outlet side of the outdoor heat exchanger 16 to the inlet side of
the accumulator 18. Further, the controller actuates the coolant
pump 41 to squeeze the coolant in a predetermined flow rate, and
switches the three-way valve 42 of the coolant circulation circuit
40 to the refrigerant flow path for allowing the coolant to bypass
the radiator 43.
[0148] In this way, the heat pump cycle 10 is switched to the
refrigerant flow path for allowing the refrigerant to flow as
illustrated by the solid arrow in FIG. 1. The cooling fluid
circulation circuit 40 is also switched to the cooling fluid flow
path for allowing the refrigerant to flow as illustrated by the
dashed arrow in FIG. 1.
[0149] The air conditioning controller with the above refrigerant
flow path and cooling fluid circuit reads a detection signal from
the sensor group for the air conditioning control and an operation
signal from the operation panel. Based on the detection signal and
the operation signal, a target outlet air temperature TAO is
calculated as the target temperature of the air to be blown into
the vehicle interior. Further, the operating states of various air
conditioning control components connected to the output side of the
air conditioning controller are determined based on the calculated
target outlet air temperature TAO and the detection signal from the
sensor group.
[0150] For example, the refrigerant discharge capacity of the
compressor 11, that is, a control signal output to the electric
motor of the compressor 11 is determined as follows. First, a
target evaporator outlet air temperature TEO of the indoor
evaporator 20 is determined based on the target outlet air
temperature TAO with reference to a control map previously stored
in the air conditioning controller.
[0151] Based on a deviation between the target evaporator outlet
air temperature TEO and the blown air temperature from the indoor
evaporator 20 detected by the evaporator temperature sensor, the
control signal to be output to the electric motor of the compressor
11 is determined such that the blown air temperature of the air
blown from the indoor evaporator 20 approaches the target
evaporator outlet air temperature TEO by use of a feedback control
method.
[0152] The control signal to be output to the servo motor of the
air mix door 34 is determined based on the target outlet air
temperature TAO, the blown air temperature of the indoor evaporator
20, and the temperature of the refrigerant discharged from the
compressor 11 detected by the discharge refrigerant temperature
sensor such that the temperature of air blown into the vehicle
interior becomes a desired temperature set by the passenger using
the vehicle indoor temperature setting switch.
[0153] During the normal heating operation, the defrosting
operation, and the waste heat collecting operation, the opening
degree of the air mix door 34 may be controlled such that the whole
volume of air in the vehicle interior blown from the blower 32
passes through the indoor condenser 12.
[0154] A control signal to be output to an electric actuator of the
inside/outside air switch 33 is determined with reference to a
control map previously stored in the air conditioning controller.
In this embodiment, basically, an outside air mode for introducing
the outside air is given a higher priority. However, when the
target outlet air temperature TAO becomes an ultra-high temperature
to require high heating performance, or in the defrosting
operation, an inside air mode for introducing the inside air is
selected.
[0155] Control signals to be output to an electric actuator of each
of the air outlet mode changing device 37a to 37c are determined
with reference to a control map previously stored in the air
conditioning controller. In this embodiment, as the target outlet
air temperature TAO increases from a low-temperature range to a
high-temperature range, the air outlet mode is switched from the
face mode to the bi-level mode, and then to the foot mode in that
order. Thus, in the heating operation, the foot mode is apt to be
selected.
[0156] Then, the control signals determined as described above are
output to various air conditioning control components. Thereafter,
until the stopping of the air conditioner for a vehicle is
requested by the operation panel, a control routine is repeated at
every predetermined control cycle. The control routine includes a
series of processes: reading of the detection signal and the
operation signal, calculation of the target outlet air temperature
TAO, determination of the operation states of various air
conditioning control components, and output of the control voltage
and the control signal in that order. Such repetition of the
control routine is basically performed in other operation modes in
the same way.
[0157] In the heat pump cycle 10 during the normal heating
operation, the high-pressure refrigerant discharged from the
compressor 11 flows into the indoor condenser 12. The refrigerant
flowing into the indoor condenser 12 exchanges heat with the
vehicle interior air blown from the blower 32 through the indoor
evaporator 20 to dissipate the heat therefrom, so that the vehicle
interior air is heated.
[0158] The high-pressure refrigerant flowing from the indoor
condenser 12 flows into the fixed throttle 13 for heating to be
decompressed and expanded by the throttle because the
opening/closing valve 15a is closed. The low-pressure refrigerant
decompressed and expanded by the fixed throttle 13 for heating
flows into an outdoor heat exchanger 16. The low-pressure
refrigerant flowing into the outdoor heat exchanger 16 absorbs heat
from the outside air blown by the blower fan 17 to evaporate
itself.
[0159] At this time, in the coolant circulation circuit 40,
switching is performed to the cooling fluid circuit for allowing
the coolant to bypass the radiator 43, which prevents the coolant
from dissipating heat to the refrigerant flowing through the
outdoor heat exchanger 16, and also prevents the coolant from
absorbing heat from the refrigerant flowing through the outdoor
heat exchanger 16. That is, the coolant never has a thermal
influence on the refrigerant flowing through the outdoor heat
exchanger 16.
[0160] Since the three-way valve 15b is switched to the refrigerant
flow path connecting the outlet side of the outdoor heat exchanger
16 to the inlet side of the accumulator 18, the refrigerant flowing
from the outdoor heat exchanger 16 flows into the accumulator 18
and is separated into liquid and gas phases. The gas-phase
refrigerant separated into by the accumulator 18 is sucked by the
compressor 11 and compressed again.
[0161] As mentioned above, in the normal heating operation, the air
in the vehicle interior is heated by the indoor condenser 12 with
heat contained in the refrigerant discharged from the compressor
11, which can perform the heating operation of the vehicle
interior.
(b) Defrosting Operation
[0162] Next, the defrosting operation will be described below. In
refrigeration cycle devices for evaporating the refrigerant by
exchanging heat between the refrigerant and outside air in the
outdoor heat exchanger 16, like the heat pump cycle 10 of this
embodiment, when a refrigerant evaporation temperature as one of
the temperatures of the outdoor heat exchanger 16 (specifically,
the temperature of an outer surface of the outdoor heat exchanger
16, or the outdoor heat exchanger 16) becomes equal to or less than
a frost formation temperature (specifically, 0.degree. C.), the
frost might be formed at the outdoor heat exchanger 16.
[0163] Such formation of the frost closes the heat-absorption air
passage 16b of the outdoor heat exchanger 16 with the frost, which
drastically reduces the heat exchange capacity of the outdoor heat
exchanger 16. In the heat pump cycle 10 of this embodiment, when
the frost formation is determined to be caused at the outdoor heat
exchanger 16 by the frost formation determination portion in the
heating operation, the defrosting operation is started.
[0164] In the defrosting operation, the air conditioning controller
stops the operation of the compressor 11, and also stops the
operation of the blower fan 17. Thus, during the defrosting
operation, the flow rate of refrigerant flowing into the outdoor
heat exchanger 16 is decreased, which leads to a decrease in volume
of outside air flowing into the heat-absorption air passage 16b of
the outdoor heat exchanger 16 and into the heat-dissipation air
passage 43b of the radiator 43, as compared to the normal heating
operation.
[0165] The air conditioning controller switches the three-way valve
42 of the coolant circulation circuit 40 to the cooling fluid
circuit for allowing the coolant to flow into the radiator 43 as
indicated by the dashed arrow in FIG. 2. Thus, the coolant
circulation circuit 40 is switched to the cooling fluid circuit for
flowing the refrigerant as indicated by the dashed arrow in FIG. 2
without circulation of the refrigerant through the heat pump cycle
10.
[0166] Thus, the heat contained in the coolant flowing through the
cooling fluid tubes 43a of the radiator 43 is transferred to the
heat-absorption air passages 16b of the outdoor heat exchanger 16
via the outer fins 50, whereby the defrosting operation of the
outdoor heat exchanger 16 is carried out. That is, the defrosting
is achieved which can effectively use the waste heat of the
electric motor MG for traveling.
(c) Waste Heat Collecting Operation
[0167] Next, the waste heat collecting operation will be described
below. Preferably, in order to suppress the over heat of the
electric motor MG for traveling, the temperature of the coolant is
maintained at a predetermined upper limit temperature or less.
Further, in order to reduce the friction loss due to an increase in
viscosity of oil for lubrication sealed into the electric motor MG
for traveling, preferably, the temperature of the coolant is
maintained at a predetermined lower limit temperature or more.
[0168] In the heat pump cycle 10 of this embodiment, when the
coolant temperature Tw is equal to or more than the predetermined
reference temperature (60.degree. C. in this embodiment) during the
heating operation, the waste heat collecting operation is
performed. In the defrosting operation, the three-way valve 15b of
the heat pump cycle 10 is performed in the same way as in the
normal heating operation, but the three-way valve 42 of the coolant
circulation circuit 40 is switched to the cooling fluid circuit for
flowing the coolant into the radiator 43 as indicated by the dashed
arrow in FIG. 3 in the same way as in the defrosting operation.
[0169] Thus, as illustrated by the solid arrow in FIG. 3, the
high-pressure and high-temperature refrigerant discharged from the
compressor 11 heats the air in the vehicle interior at the indoor
condenser 12, and is then decompressed and expanded by the fixed
throttle 13 for heating to flow into the outdoor heat exchanger 16
in the same way as in the normal heating operation.
[0170] Since the three-way valve 42 is switched to the cooling
fluid circuit for flowing the coolant into the radiator 43, the
low-pressure refrigerant flowing into the outdoor heat exchanger 16
absorbs both the heat contained in the outside air blown by the
blower fan 17 and the heat contained in the coolant and transmitted
thereto via the outer fins 50 to evaporate itself. Other actuations
are the same as those in the normal heating operation.
[0171] As described above, in the waste heat collecting operation,
the air in the vehicle interior is heated at the indoor condenser
12 with the heat of the refrigerant discharged from the compressor
11, which can perform heating of the vehicle interior. At this
time, the refrigerant absorbs not only the heat contained in the
outside air, but also the heat contained in the coolant and
transmitted thereto via the outer fins 50, which can achieve the
heating of the vehicle interior effectively using the waste heat of
the electric motor MG for traveling.
(d) Cooling Operation
[0172] The cooling operation is started when the cooling operation
mode is selected by the selection switch with the operation switch
of the operation panel is turned on (ON). In the cooling operation,
the air conditioning controller opens the opening/closing valve
15a, and switches the three-way valve 15b to the refrigerant flow
path for connecting the outlet side of the outdoor heat exchanger
16 to the inlet side of the fixed throttle 19 for cooling. Thus,
the heat pump cycle 10 is switched to the refrigerant flow path for
flowing the refrigerant as indicated by the solid arrow in FIG.
4.
[0173] At this time, when the coolant temperature Tw is equal to or
more than the reference temperature, the three-way valve 42 of the
coolant circulation circuit 40 is switched to the cooling fluid
circuit for flowing the coolant into the radiator 43. In contrast,
when the coolant temperature Tw is less than the predetermined
reference temperature, the three-way valve 42 is switched to the
cooling fluid circuit for allowing the coolant to bypass the
radiator 43. The flow of the coolant obtained when the coolant
temperature Tw is equal to or more than the reference temperature
is indicated by the dashed arrow in FIG. 4.
[0174] In the heat pump cycle 10 during the cooling operation, the
high-pressure refrigerant discharged from the compressor 11 flows
into the indoor condenser 12, and exchanges heat with the air in
the vehicle interior blown from the blower 32 and having passed
through the indoor evaporator 20 to dissipate heat therefrom. The
high-pressure refrigerant flowing from the indoor condenser 12
flows into the outdoor heat exchanger 16 via the bypass passage 14
for the fixed throttle because the opening/closing valve 15a is
opened. The low-pressure refrigerant flowing into the outdoor heat
exchanger 16 further radiates heat toward the outside air blown by
the blower fan 17.
[0175] Since the three-way valve 15b is switched to the refrigerant
flow path for connecting the outlet side of the outdoor heat
exchanger 16 to the inlet side of the fixed throttle 19 for
cooling, the refrigerant flowing from the outdoor heat exchanger 16
is decompressed and expanded by the fixed throttle 19 for cooling.
The refrigerant flowing from the fixed throttle 19 for cooling
flows into the indoor evaporator 20, and absorbs heat from the air
in the vehicle interior blown by the blower 32 to evaporate itself.
In this way, the air in the vehicle interior can be cooled.
[0176] The refrigerant flowing from the indoor evaporator 20 flows
into the accumulator 18, and is then separated into liquid and gas
phases by the accumulator. The gas-phase refrigerant separated into
by the accumulator 18 is sucked into and compressed by the
compressor 11 again. As mentioned above, during the cooling
operation, the low-pressure refrigerant absorbs heat from the air
in the vehicle interior and evaporates itself at the indoor
evaporator 20 to thereby cool the air in the vehicle interior,
which can perform cooling of the vehicle interior.
[0177] As described above, the air conditioner 1 for the vehicle in
this embodiment can perform switching among the refrigerant flow
paths of the heat pump cycle 10, and among the cooling fluid
circuits of the coolant circulation circuit 40 to thereby carry out
various operations. Further, in the defrosting operation of this
embodiment, the waste heat of the electric motor MG for traveling
can be effectively used to defrost the outdoor heat exchanger 16 as
will be described later.
[0178] More specifically, in this embodiment, the heat-absorption
air passage 16b of the outdoor heat exchanger 16 and the
heat-dissipation air passage 43b of the radiator 43 are provided
with the outer fins 50 made of the same metal material to enable
the heat transfer between the refrigerant tubes 16a and the cooling
fluid tubes 43a. Thus, during the defrosting operation, the heat
contained in the coolant can be transmitted to the outdoor heat
exchanger 16 via the outer fins 50.
[0179] Therefore, this embodiment can suppress the loss in heat
transfer as compared to the related art cycle in which heat
contained in the coolant is transmitted to the outdoor heat
exchanger 16 via air, and thus can effectively use the waste heat
of the electric motor MG for traveling for defrosting the outdoor
heat exchanger 16. Moreover, this embodiment can reduce the time
for the defrosting operation.
[0180] During the defrosting operation, the operation of the
compressor 11 is stopped and the flow rate of refrigerant flowing
into the outdoor heat exchanger 16 is decreased (specifically, set
to zero (0)) as compared to the time before the defrosting
operation, which can prevent the heat transmitted to the outdoor
heat exchanger 16 via the outer fins 50 from being absorbed in the
refrigerant flowing through the refrigerant tubes 16a. Thus, the
waste heat of the electric motor MG for traveling can be used more
effectively to defrost the outdoor heat exchanger 16 during the
defrosting operation.
[0181] In other words, during the defrosting operation, the
operation of the compressor 11 is stopped to decrease the heating
capacity for heating the air at the indoor condenser 12 (in this
embodiment, such that the heating capacity is not exhibited), which
decreases the amount of heat of the refrigerant absorbed in the
outdoor heat exchanger 16. Thus, the waste heat of the electric
motor MG for traveling can be used more effectively to defrost the
outdoor heat exchanger 16 in the defrosting operation.
[0182] During the defrosting operation, the operation of the blower
fan 17 is stopped to decrease the volume of outside air flowing
into the heat-absorption air passages 16b and the heat dissipation
air passage 43b (specifically, set to zero (0)), which can prevent
the heat transmitted to the outdoor heat exchanger 16 via the outer
fins 50 from being absorbed in the outside air flowing through the
heat-absorption air passages 16b and the heat-dissipation air
passage 43b. Thus, the waste heat of the electric motor MG for
traveling can be used more effectively to defrost the outdoor heat
exchanger 16 in the defrosting operation.
[0183] In the heat pump cycle 10 of this embodiment, during the
normal heating operation, the three-way valve 42 of the coolant
circulation circuit 40 is switched to the cooling fluid circuit for
allowing the coolant to bypass the radiator 43 to thereby store the
heat (generated heat) contained in the electric motor MG for
traveling, in the coolant. Thus, during the defrosting operation,
the defrosting operation can be completed by the stored heat in a
short time.
[0184] In the heat exchanger structure 70 of this embodiment, the
radiator 43 is arranged on the windward side of the flow direction
X of the outside air blown by the blower fan 17 with respect to the
outdoor heat exchanger 16. In other words, in the heat exchanger
structure 70, the outdoor heat exchanger 16 and the radiator 43 are
arranged in series such that the outside air flows from the
radiator 43 to the outdoor heat exchanger 16.
[0185] Thus, the heat contained in the coolant can be transferred
to the outdoor heat exchanger 16 not only via the outer fins 50,
but also via air. That is, even when the blower fan 17 is stopped,
the heat contained in the coolant can be transferred to the outdoor
heat exchanger 16 by air pressure (ram air pressure) in the
traveling direction of the traveling vehicle via the outside air
passing through the heat exchanger structure 70. Thus, during the
defrosting operation, the heat supplied from the electric motor MG
for traveling can be used more effectively to defrost the outdoor
heat exchanger 16.
[0186] The frost formation determination portion included in the
air conditioning controller of this embodiment determines that the
frost is formed in the outdoor heat exchanger 16 when the vehicle
speed is equal to or less than the reference vehicle speed, and
when the refrigerant temperature Te on the outlet side of the
outdoor heat exchanger 16 is equal to or less than 0.degree. C.
Accordingly, the frost formation can be appropriately determined
taking into consideration the vehicle speed.
[0187] That is, when the vehicle travels at low speed, the ram air
pressure becomes lower and the volume of outside air flowing into
the engine room is decreased. Thus, the volume of outside air
flowing into each of the outdoor heat exchanger 16 and the radiator
43 is decreased. Thus, in the defrosting operation, the heat
transferred to the outdoor heat exchanger 16 via the outer fins 50
is prevented from being absorbed in the outside air, which can
achieve the effective defrosting.
[0188] Further, in the heat pump cycle 10 of this embodiment, when
the coolant temperature Tw detected by the coolant temperature
sensor 52 is equal to or more than the reference temperature, the
waste heat collecting operation is performed by switching the
three-way valve 42 to a cooling fluid circuit for flowing the
coolant in the radiator 43. Thus, the heat contained in the coolant
is dissipated by the radiator 43, which can protect the electric
motor MG for traveling from over heat.
[0189] Additionally, in the waste heat collecting operation, the
heat dissipated by the radiator 43 is transferred to the outdoor
heat exchanger 16, and can be absorbed in the refrigerant, which
can improve a coefficient of performance (COP) of the heat pump
cycle 10, and thus can effectively heat the air in the vehicle
interior. As a result, the heating performance of the air
conditioner 1 for the vehicle can be improved.
[0190] In this embodiment, the three-way valve 42 is switched to
the cooling fluid circuit for flowing the coolant into the radiator
43 to perform the waste heat collecting operation based on the
reference temperature of 60.degree. C. The reference temperature
can be determined by the heat exchange performance or the like of
the outdoor heat exchanger 16 and the like.
[0191] For example, when WW (g) is the weight of the coolant in the
coolant circulation circuit 40, WG (g) is the amount of frost
formed in the outdoor heat exchanger 16, TR (.degree. C.) is the
temperature of air blown from the outdoor heat exchanger 16, the
amount of storage heat Qst stored in the coolant in the coolant
circulation circuit 40 is represented by the following formula F1,
and the amount of heat required for defrosting (hereinafter
referred to as a "defrosting heat amount") Qdf is represented by
the following formula F2:
Qst=WW.times.Specific Heat of Coolant.times.(Tw-TR) (F1)
Qdf=WG.times.Latent Heat of Vaporization of Water-Specific Heat of
Water.times.
TR+Outdoor Heat Exchanger 16.times.Heat Capacity.times.TR+Amount of
Heat
Dissipated into Air (F2)
[0192] in which the storage heat amount Qst needs to exceed the
defrosting heat amount Qdf in order to ensure the defrosting of the
outdoor heat exchanger 16.
[0193] Further, when the heat capacity of the outdoor heat
exchanger 16 and the amount of heat dissipated into air in the
formula F2 are considered as ignorable ones, the minimum defrosting
heat amount Qdf2 required to melt the frost formed at the outdoor
heat exchanger 16 is represented by the following formula F3:
Qdf2=WG.times.Latent Heat of Vaporization of Water-Specific Heat of
Water.times.TR (F3)
[0194] Therefore, in order to perform the defrosting, at least the
following formula F4 has to be satisfied:
Qst>Qdf2 (F4)
[0195] Substitution of the formulas (F1) and (F3) into the above
formula (F4) can yield the following formula (F5):
Tw>TR+(WG.times.Latent Heat of Vaporization of Water-Specific
Heat of
Water.times.TR)/(WW.times.Specific Heat of Coolant) (F5)
[0196] Therefore, the temperature Tw satisfying the above formula
F5 may be determined as the reference temperature.
[0197] In other words, the heat pump cycle of this embodiment
includes coolant temperature detection portion (coolant temperature
sensor 52) for detecting the coolant temperature Tw of the coolant
flowing into the vehicle-mounted device (electric motor MG for
traveling) generating heat in operation, and outdoor blown air
temperature detection portion for detecting the air temperature TR
of air blown from the outdoor heat exchanger 16. The cooling fluid
circuit switching device (three-way valve 42) may perform switching
to the cooling fluid circuit for allowing the cooling fluid
(coolant) to flow into the heat-dissipation heat exchanger
(radiator 43) when the coolant temperature TW detected by the
coolant temperature detection portion (coolant temperature sensor
52) and the air temperature TR detected by the outdoor blown air
temperature detection portion satisfy the following
relationship:
Tw>TR+(WG.times.Latent Heat of Vaporization of Water-Specific
Heat of
Water.times.TR)/(WW.times.Specific Heat of Coolant).
[0198] In the heat pump cycle 10 of this embodiment, during the
heating operation (heater operation), the flow direction of
refrigerant flowing through the refrigerant tubes 16a of the
outdoor heat exchanger 16 is the same as that of refrigerant
flowing through the refrigerant tubes 16a during the cooling
operation (cooler operation). As viewed from the flow direction of
outside air, the positional relationship between a heat exchange
region on a refrigerant inlet side of the outdoor heat exchanger 16
and a heat exchange region on a refrigerant outlet side thereof
does not change between the heating operation and the cooling
operation. Therefore, the positional relationship between the
temperature distribution of the heat exchange region of the outdoor
heat exchanger 16 and the temperature distribution of the heat
exchange region of the heat disspation heat exchanger 43 does not
change.
[0199] That is, the outdoor heat exchanger 16 and the heat
disspation heat exchanger 43 are macroscopically regarded as one
heat exchanger structure 70. In that case, during the cooling
operation for dissipating heat from the refrigerant at the outdoor
heat exchanger 16, a heat exchange region on the refrigerant inlet
side of the outdoor heat exchanger 16 for flowing the refrigerant
having a superheat degree at a relatively high temperature can be
superimposed in the flow direction of the outside air, on a heat
exchange region on the cooling fluid inlet side of the heat
disspation heat exchanger 43 for flowing the cooling fluid at a
relatively high temperature. Further, a heat exchange region on the
refrigerant outlet side of the outdoor heat exchanger 16 for
flowing the refrigerant having a superheat degree at a relatively
low temperature can be superimposed in the flow direction of the
outside air, on a heat exchange region on the cooling fluid outlet
side of the heat disspation heat exchanger 43 for flowing the
cooling fluid at a relatively low temperature. With this
arrangement, the flow of the refrigerant through the outdoor heat
exchanger 16 and the flow of the cooling fluid through the heat
disspation heat exchanger 43 can be made parallel to achieve the
effective heat exchange.
[0200] Further, in the heating operation for evaporating the
refrigerant at the outdoor heat exchanger 16, a heat exchange
region on the refrigerant inlet side of the outdoor heat exchanger
16 for flowing the refrigerant at a relatively low temperature can
be superimposed in the flow direction of the outside air, on a heat
exchange region on the cooling fluid inlet side of the heat
disspation heat exchanger 43 for flowing the cooling fluid at a
relatively high temperature. As a result, the frost can be
effectively prevented from being formed in the heat exchange region
on the refrigerant inlet side of the outdoor heat exchanger 16 for
allowing the refrigerant to flow therethrough at a relative low
temperature.
Second Embodiment
[0201] Unlike the first embodiment, in this embodiment, as shown in
the entire configuration diagram of FIG. 6, the indoor condenser 12
is removed, and a brine circuit 60 is provided for circulating
brine, that is, a heating fluid by way of example. FIG. 6 is an
entire configuration diagram showing refrigerant flow paths and the
like during the heating operation in this embodiment, in which the
flow of refrigerant in the heat pump cycle 10 is indicated by the
solid line, and the flow of coolant in the coolant circulation
circuit 40 is indicated by the dashed arrow.
[0202] In FIG. 6, the same or equivalent part as that of the first
embodiment is designated by the same reference character. The same
goes for the following other drawings.
[0203] Brine in this embodiment is a heating fluid for transferring
heat contained in the refrigerant discharged from the compressor 11
to the air blown into the vehicle interior. Like the coolant as the
cooling fluid, an ethylene glycol aqueous solution can be used. The
brine circuit 60 includes a brine pump 61, a brine-refrigerant heat
exchanger 62, and a heater core 63.
[0204] The brine pump 61 is an electric pump for squeezing the
brine into the heater core 63 of the brine-refrigerant heat
exchanger 62. The brine pump 61 has the same basic structure as
that of the coolant pump 41 of the coolant circulation circuit 40.
The brine-refrigerant heat exchanger 62 is a heat exchanger for
exchanging heat between the refrigerant discharged from the
compressor 11 and flowing through a refrigerant passage 62b, and
the brine flowing through the brine passage 62a.
[0205] Specifically, the brine-refrigerant heat exchanger 62 can
employ a double tube type heat exchanger structure comprised of an
outer pipe forming the brine passage 62a, and an inner pipe
disposed in the outer pipe for forming the refrigerant passage 62b.
Alternatively, the refrigerant passage 62b may be formed as the
outer pipe, and the brine passage 62a may be formed as the inner
pipe. The refrigerant pipe forming the refrigerant passage 62b and
the refrigerant pipe forming the brine passage 62a can be bonded
together by brazing to form the heat exchanging structure and the
like.
[0206] The heater core 63 is disposed in the casing 31 of the
indoor air conditioning unit 30 of the air conditioner 1 for the
vehicle. The heater core 63 is a heat exchanger for heating that
exchanges heat between the brine passing therethrough and the
vehicle-interior air having passed through the indoor evaporator
20. Thus, the heater core 63 of this embodiment serves as the
user-side heat exchanger, which is the same as the indoor condenser
12. The structures and operations of other components in this
embodiment are the same as those in the first embodiment.
[0207] Accordingly, even the operation of the air conditioner 1 for
the vehicle of this embodiment can provide the same effects as
those of the first embodiment. Further, since the brine circuit 60
is provided in this embodiment, the heating capacity of the heater
core 63 can be easily adjusted by changing a coolant squeezing
capacity of the brine pump 61.
[0208] Like the coolant, the brine in the brine pump 61 can also
store the heat contained in the refrigerant discharged from the
compressor 11 during the normal heating operation. Thus, even when
the compressor 11 is stopped in the defrosting operation, the brine
pump 61 can be operated to perform an auxiliary heating operation
of the vehicle interior.
Third Embodiment
[0209] Unlike the heat pump cycle 10 of the first embodiment, as
shown in the entire configuration diagram of FIG. 7, in this
embodiment, an outdoor unit bypass passage 64 is added for allowing
the refrigerant flowing from the fixed throttle 13 for heating or
the bypass passage 14 for the fixed throttle to bypass the outdoor
heat exchanger 16. And, an opening/closing valve 15c is further
added for opening and closing the outdoor unit bypass passage
64.
[0210] FIG. 7 is an entire configuration diagram showing
refrigerant flow paths during the defrosting operation in this
embodiment, in which the flow of refrigerant in the heat pump cycle
10 is indicated by a solid line, and the flow of coolant in the
coolant circulation circuit 40 is indicated by a dashed arrow.
[0211] The opening/closing valve 15c has the same basic structure
as that of the opening/closing valve 15a disposed in the bypass
passage 14 for the fixed throttle. The loss in pressure generated
in the refrigerant passing through the opening/closing valve 15c
when the opening/closing valve 15c is opened is much smaller than
the loss in pressure generated in the refrigerant when the
refrigerant passes through the outdoor heat exchanger 16.
[0212] Thus, when the opening/closing valve 15c is opened, most of
the refrigerant flowing from the fixed throttle 13 for heating or
the bypass passage 14 for the fixed throttle flows into the outdoor
unit bypass passage 64, and hardly flows into the outdoor heat
exchanger 16.
[0213] In this embodiment, in the defrosting operation, the air
conditioning controller opens the opening/closing valve 15c without
stopping the operation of the compressor 11, and in other operation
modes, the opening/closing valve 15c is closed. Thus, during the
defrosting operation, the flow rate of refrigerant flowing into the
outdoor heat exchanger 16 is decreased. The structures and
operations of other components in this embodiment are the same as
those in the first embodiment.
[0214] Thus, even the operation of the air conditioner 1 for the
vehicle of this embodiment can provide the same effects as those of
the first embodiment. Further, since the operation of the
compressor 11 is not stopped during the defrosting operation in
this embodiment, the indoor condenser 12 can exhibit the heating
capacity of the air with the heat contained in the refrigerant
discharged from the compressor 11 to thereby perform the heating
operation of the vehicle interior.
[0215] At this time, in the defrosting operation, the flow
direction of refrigerant passing through the refrigerant tubes 16a
of the outdoor heat exchanger 16 is the same as that in the heating
operation (normal operation), which enables quick transfer from the
normal operation to the defrosting operation, or from the
defrosting operation to the normal operation. As a result, the
defrosting time can be further reduced.
[0216] As viewed from the flow direction of the outside air, the
positional relationship between the heat exchange region on the
refrigerant inlet side of the outdoor heat exchanger 16 and the
heat exchange region on the refrigerant outlet side thereof does
not change with respect to the heat exchange region of the radiator
43, which can suppress large fluctuations in amount of heat
transferred between the refrigerant flowing through the refrigerant
tubes 16a of the outdoor heat exchanger 16 and the cooling fluid
flowing through the cooling fluid tubes 43a of the radiator 43.
[0217] That is, when the heat exchange is performed between the
refrigerant tubes 16a of the outdoor heat exchanger 16 via the
outer fins 50 and the cooling fluid tubes 43a of the radiator 43,
the relationship between the flow of the entire refrigerant in the
outdoor heat exchanger 16 and the flow of the entire coolant in the
radiator 43 might be changed from the opposite to the parallel, or
from the parallel to the opposite in the related art. However, this
embodiment can avoid such a situation.
[0218] As a result, the heat pump cycle of this embodiment can
suppress the large fluctuations in amount of heat transfer between
the refrigerant flowing through the refrigerant tubes 16a and the
cooling fluid flowing through the cooling fluid tubes 43a, thus
improving the flexibility in design of the outdoor heat exchanger
16 and the radiator 43.
Fourth Embodiment
[0219] This embodiment has the substantially same cycle structure
as that of the heat pump cycle 10 of the third embodiment, but has
a different control form of the air conditioning controller in the
defrosting operation, which will be described below by way of
example.
[0220] Specifically, in this embodiment, during the defrosting
operation, the air conditioning controller opens the
opening/closing valve 15a and the opening/closing valve 15c without
stopping the operation of the compressor 11, and switches the
three-way valve 15b to the refrigerant flow path for connecting the
outlet side of the outdoor heat exchanger 16 (specifically, the
outlet side of the outdoor unit bypass passage 64) to the inlet
side of the fixed throttle 19 for cooling.
[0221] Thus, in this embodiment, in the defrosting operation, as
shown in FIG. 8, the heat pump cycle 10 is switched to the cycle
for circulating the refrigerant from the compressor 11, to the
indoor condenser 12 (outdoor unit bypass passage 64), the fixed
throttle 19 for cooling, the indoor evaporator 20, the accumulator
18, and the compressor 11 in that order.
[0222] The refrigerant flowing from the fixed throttle 19 for
cooling takes latent heat of vaporization from the air upon
evaporating at the indoor evaporator 20, so that the air can be
cooled. Then, when the refrigerant discharged from the compressor
11 dissipates heat at the indoor condenser 12, the cooled air is
re-heated. The structures and operations of other components in
this embodiment are the same as those in the first embodiment.
[0223] Thus, even the operation of the air conditioner 1 for the
vehicle of this embodiment can provide the same effects as those of
the third embodiment. Further, in this embodiment, the air cooled
by evaporating the refrigerant at the indoor evaporator 20 can be
heated again by the indoor condenser 12 in the defrosting
operation, which can achieve the defrosting and heating of the
vehicle interior.
Fifth Embodiment
[0224] Unlike the heat pump cycle 10 of the first embodiment, as
shown in the entire configuration diagram of FIG. 9, in this
embodiment, a shutter device (passage interruption means) is added
for opening or closing an inflow route for flowing the outside air
into the radiator 43, by way of example. FIG. 9 is an entire
configuration diagram showing refrigerant flow paths or the like in
the defrosting operation of this embodiment, in which the flow of
refrigerant in the heat pump cycle 10 is indicated by a solid line
and the flow of coolant in the coolant circulation circuit 40 is
indicated by a dashed arrow.
[0225] Specifically, a shutter device 65 is formed by combining a
plurality of cantilever door plates. The shutter device 65 is
designed to open the inflow route for flowing the outside air into
the radiator 43 by displacing the door plate in the direction
parallel to the flow of air from the blower fan 17, and to close
the inflow route for flowing the outside air into the radiator 43
by displacing the door plate in the direction intersecting the air
flow from the blower fan 17.
[0226] The radiator 43 is positioned on the windward side in the
flow direction X of the outside air blown by the blower fan 17 with
respect to the outdoor heat exchanger 16. The shutter device 65
closes the inflow route for flowing the outside air into the
radiator 43 to thereby block the inflow route for flowing the
outside air into the outdoor heat exchanger 16.
[0227] The shutter device 65 may be composed of a slide door or the
like. The shutter device 65 is driven by a servo motor (not shown)
whose operation is controlled by a control signal output from the
air conditioning controller.
[0228] In this embodiment, in the defrosting operation, the shutter
device 65 is operated to close the inflow route for flowing the
outside air into the radiator 43, and in other operation modes, the
shutter device 65 is operated to open the inflow route for flowing
the outside air into the radiator 43. Thus, during the defrosting
operation, the volume of outside air flowing into the
heat-absorption air passage 16b and into the heat-dissipation air
passage 43b is decreased. The structures and operations of other
components in this embodiment are the same as those in the first
embodiment.
[0229] Thus, even the operation of the air conditioner 1 for the
vehicle of this embodiment can provide the same effects as those of
the first embodiment. Further, in this embodiment, the shutter
device 65 is operated to close the inlet route for flowing the
outside air into the radiator 43 during the defrosting operation,
which can prevent the inflow of the outside air into the
heat-absorption air passages 16b and the heat dissipation air
passage 43b due to the ram air pressure during the traveling of the
vehicle.
Sixth Embodiment
[0230] In this embodiment, unlike the first embodiment, the
specific structure of the heat exchanger structure 70 is modified,
which will be described below by way of example. The details of the
heat exchanger structure 70 will be explained below using FIGS. 10
to 13. FIG. 10 shows a perspective view of the contour of the heat
exchanger structure 70 of this embodiment. FIG. 11 is an exploded
perspective view of the heat exchanger structure 70. FIG. 12 is a
cross-sectional view taken along the line A-A of FIG. 10. FIG. 13
is an exemplary perspective view for explaining the flow of
refrigerant and the flow of coolant in the heat exchanger structure
70.
[0231] First, as shown in the exploded perspective view of FIG. 11,
in the heat exchanger structure 70 of this embodiment, the
refrigerant tubes 16a of the outdoor heat exchanger 16 are arranged
in two lines and the cooling fluid tubes 43a of the radiator 43 are
also arranged in two lines, in the flow direction X of the outside
air blown by the blower fan 17. Further, the refrigerant tubes 16a
and the cooling fluid tubes 43a are alternately arranged and
laminated over each other.
[0232] Thus, in this embodiment, the heat-absorption air passage
16b and the heat-dissipation air passage 43b form one space. The
outer fins 50 which are the same as those of the first embodiment
are arranged in the heat-absorption air passage 16b and the
heat-dissipation air passage 43b which form one space, and the
respective outer fins 50 are bonded to the tubes 16a and 43a.
[0233] On one end side (lower end side shown in FIGS. 10 to 13) in
the longitudinal direction of the refrigerant tubes 16a and the
cooling fluid tubes 43a 43a, a tank 16c on the refrigerant side is
provided for collecting or distributing the refrigerant flowing
through the refrigerant tubes 16a. On the other end side (upper end
side shown in FIGS. 10 to 13) in the longitudinal direction, a tank
43c on the cooling fluid side is provided for collecting or
distributing the refrigerant flowing through the tubes 43a for
cooling fluid.
[0234] The refrigerant side tank 16c and the cooling fluid side
tank 43c have the same basic structure. First, the refrigerant side
tank 16c includes a refrigerant side plate 161 for connection to
the refrigerant tubes 16a and the cooling fluid tubes 43a which are
respectively arranged in two lines, a refrigerant side intermediate
plate 162 to be fixed to the refrigerant side connection plate 161,
and a refrigerant side tank 163.
[0235] As shown in the cross-sectional view of FIG. 12, the
refrigerant side intermediate plate 162 is fixed to the refrigerant
side connection plate 161 to form a plurality of recesses 162b for
forming a plurality of spaces in communication with the cooling
fluid tubes 43a, between the refrigerant side connection plate 161
and the plate 162 itself. These spaces serve as a communicating
space for the cooling fluid that connects and communicates the
cooling fluid tubes 43a together arranged in two lines in the flow
direction X of the outside air.
[0236] FIG. 12 shows the cross section of the surroundings of
recesses 432b provided in the cooling fluid side intermediate plate
432 for clearly illustration. As mentioned above, since the
refrigerant side tank 16c has the same basic structure as that of
the cooling fluid side tank 43c, the refrigerant side connection
plate 161 and the recesses 162b are represented in parentheses.
[0237] A through hole 162a is provided at a part of the refrigerant
side intermediate plate 162 corresponding to the refrigerant tube
16a to penetrate both sides of the plate. The refrigerant tube 16a
is inserted into the through hole. Thus, on one end of the
refrigerant side tank 16c, the refrigerant tube 16a protrudes
toward the refrigerant side tank 16c as compared to the cooling
fluid tube 43a.
[0238] The refrigerant side tank 163 is fixed to the refrigerant
side connection plate 161 and the refrigerant side intermediate
plate 162 to form a collection space 163a for collecting therein
the refrigerant and a distribution space 163b for distributing the
refrigerant. Specifically, the refrigerant side tank 163 is formed
by pressing a metal plate in double mountain shape (W-like shape)
as viewed in the longitudinal direction.
[0239] The center of the double mountain shape of the refrigerant
side tank 163 is bonded to the refrigerant side intermediate plate
162 to participate the tank 163 into the collection space 163a and
the distribution space 163b. In this embodiment, the collection
space 163a is disposed on the windward side of the flow direction X
of the outside air, and the distribution space 163b is disposed on
the leeward side of the flow direction X of the outside air.
[0240] One end of the refrigerant side tank 163 in the longitudinal
direction is connected to a refrigerant inflow pipe 164 for flowing
the refrigerant into the distribution space 163b, and to a
refrigerant outflow pipe 165 for flowing the refrigerant from the
collection space 163a. The other end of the refrigerant side tank
163 in the longitudinal direction is closed by a closing
member.
[0241] On the other hand, the cooling fluid side tank 43c with the
same structure as described above also includes a cooling fluid
side connection plate 431, a cooling fluid side intermediate plate
432 fixed to the plate 431, and a cooling fluid side tank 433.
[0242] As shown in the cross-sectional view shown in FIG. 12, a
refrigerant communication space that can communicate the two-lined
the refrigerant tubes 16a together in the flow direction X of the
outside air is formed by the recesses 432b provided in the cooling
fluid side intermediate plate 432 between the cooling fluid side
connection plate 431 and the cooling fluid side intermediate plate
432.
[0243] A through hole 432a is provided at a part of the cooling
fluid side intermediate plate 432 corresponding to the cooling
fluid tube 43a to penetrate both sides of the plate. The cooling
fluid tube 43a is inserted into the through hole. Thus, on the side
of the cooling fluid side tank 43c, the cooling fluid tube 43a
protrudes toward the cooling fluid side tank 43c as compared to the
refrigerant tube 16a.
[0244] Further, the cooling fluid side tank 433 is fixed to the
cooling fluid side connection plate 431 and the cooling fluid side
intermediate plate 432 to form a collection space 433a for
collecting therein the cooling media and a distribution space 433b
for distributing the cooling media. Specifically, in this
embodiment, the distribution space 433b is disposed on the windward
side of the flow direction X of the outside air, and the collection
space 433a is disposed on the leeward side of the flow direction X
of the outside air.
[0245] One end of the cooling fluid side tank 433 in the
longitudinal direction is connected to a cooling fluid inflow pipe
434 for flowing the cooling fluid into the distribution space 433b,
and to a cooling fluid outflow pipe 435 for flowing the cooling
fluid from the collection space 433a. The other end of the cooling
fluid side tank 43c in the longitudinal direction is closed by a
closing member.
[0246] Thus, in the heat exchanger structure 70 of this embodiment,
as shown in the exemplary perspective view of FIG. 13, the
refrigerant flowing into the distribution space 163b of the
refrigerant side tank 16c via the refrigerant inflow pipe 164 flows
into each refrigerant tube 16a disposed on the leeward side in the
flow direction X of the outside air among the refrigerant tubes 16a
arranged in two lines.
[0247] And, the refrigerant flowing from each refrigerant tube 16a
disposed on the leeward side flows into each refrigerant tube 16a
disposed on the windward side in the flow direction X of the
outside air via a space formed between the cooling fluid side
connection plate 431 of the cooling fluid side tank 43c and the
cooling fluid side intermediate plate 432.
[0248] Then, as indicated by a solid arrow in FIG. 13, the
refrigerants flowing from the refrigerant tubes 16a disposed on the
windward side are collected into the collection space 163a of the
refrigerant side tank 16c, and then flow from the refrigerant
outlet pipe 165. That is, in the heat exchanger structure 70 of
this embodiment, the refrigerant flows turning around from the
refrigerant tubes 16a on the leeward side to the cooling fluid side
tank 43c, and the refrigerant tubes 16a on the windward side in
that order.
[0249] Likewise, as illustrated by the dashed arrow in FIG. 13, the
coolant flows turning around from the cooling fluid tubes 43a on
the windward side to the refrigerant side tank 16c, and the cooling
fluid tubes 43a on the leeward side in that order. The structures
and operations of other components in this embodiment are the same
as those in the first embodiment. Even the operation of the air
conditioning 1 for the vehicle of this embodiment can provide the
same effects as those of the first embodiment.
[0250] Further, in this embodiment, the refrigerant tubes 16a and
the cooling fluid tubes 43a in the heat exchanger structure 70 are
alternately arranged and laminated, so that the outdoor heat
exchanger 16 can be effectively defrosted during the defrosting
operation.
[0251] That is, in the heat exchanger structure 70 of this
embodiment, the refrigerant tube 16a is disposed between the
cooling fluid tubes 43a, and the cooling fluid tube 43a is disposed
between the refrigerant tubes 16a, whereby the heat-absorption air
passage 16b and the heat-dissipation air passage 43b form one air
passage.
[0252] As compared to the case where the radiator 43 and the
outdoor heat exchanger 16 are disposed in series with respect to
the flow direction X of the outside air, in this embodiment, the
tube 43ab for the cooling fluid and the refrigerant tube 16a can be
arranged close to each other. Thus, the cooling fluid tube 43a can
be disposed near the frost generated in the refrigerant tube 16a.
As a result, the outdoor heat exchanger 16 can be effectively
defrosted in the defrosting operation. The heat exchanger structure
70 of this embodiment may be applied to the heat pump cycles 10 of
the second to fifth embodiments.
Seventh Embodiment
[0253] In the above first embodiment, the air conditioning
controller stops the operation of the compressor 11 during the
defrosting operation, by way of example. If the operation of the
compressor 11 is stopped during the defrosting operation, the
indoor condenser 12 cannot heat the air. As a result, the
controller might blow the air having at a temperature lower than
the temperature desired by the passenger in the vehicle. Once the
defrosting operation is started, the passenger can feel unsatisfied
with heating.
[0254] In contrast, in this embodiment, even when the air cannot be
heated by the indoor condenser 12 in the defrosting operation, the
vehicle interior linkage control is performed for suppressing the
loss in heating to the passenger. The linkage control will be
described below using the flowcharts shown in FIGS. 14 to 17.
[0255] FIG. 14 is a flowchart showing a basic control flow of the
vehicle interior linkage control. The basic control flow is
executed as a sub-routine which is an interrupt process for a main
routine to be executed by the air conditioner 1 for the vehicle.
When a defrosting flag deffg indicative of the execution of the
defrosting operation does not become 1 within a predetermined time
assigned as an execution time of the basic control flow, the
operation returns to the main routine.
[0256] In step S100 of the basic control flow, a defrosting
determination process is executed to determine whether or not the
frost is formed at the outdoor heat exchanger 16 and whether or not
the defrosting is performed. The details of the defrosting
determination process will be described using FIG. 15. In step S101
of FIG. 15, the defrosting flag deffg or the like is
initialized.
[0257] Subsequently, in step S102, it is determined whether or not
the frost is formed at the outdoor heat exchanger 16. Specifically,
when the temperature of the outer surface of the heat exchanger 16
is determined to be equal to or less than 0.degree. C., the frost
is determined to be formed, and then, the operation proceeds to
step S103 with the deffg kept to 1 (deffg=1). In contrast, when the
temperature of the outer surface of the outdoor heat exchanger 16
is determined not to be equal to or less than 0.degree. C., the
frost is determined not to be formed, and then, the operation
returns to step S102 again with the deffg kept to zero
(deffg=0).
[0258] In step S103, it is determined whether the engine is
operated or not. When the engine is determined to be operated in
step S103, the deffg is kept to 1 (deffg=1), and the operation
proceeds to step S104. When the engine is determined not to be
operated, the operation proceeds to an air conditioning mode
changing control shown in step S200 of FIG. 14.
[0259] In step S104, like step S102, it is determined whether the
frost is formed at the outer heat exchanger 16 or not.
Specifically, when the temperature of the outer surface of the
outdoor heat exchanger 16 is determined to be equal to or less than
0.degree. C., the frost is determined to be formed, and then the
operation proceeds to step S105 with the deffg kept to 1 (deffg=1).
When the temperature of the outer surface of the outdoor heat
exchanger 16 is determined not to be equal to or less than
0.degree. C., the frost is determined not to be formed, and then
the operation returns again to step S102.
[0260] In step S105, it is determined whether or not the coolant
temperature Tw reaches the predetermined defrosting reference
temperature KTwdef. In step S105, when the coolant temperature Tw
is determined to reach the predetermined defrosting reference
temperature KTwdef (in this embodiment, 10.degree. C.), the outdoor
heat exchanger 16 can be defrosted by flowing the coolant into the
radiator 43, and then the operation proceeds to step S106 with the
deffg kept to 1 (deffg=1).
[0261] In step S105, when the coolant temperature Tw is determined
not to reach the predetermined defrosting reference temperature
KTwdef, even if the coolant flows into the radiator 43, the outdoor
heat exchanger 16 cannot be defrosted, and then the operation
returns to step S102 again.
[0262] In step S106, it is determined whether or not an inside air
temperature (temperature of the vehicle interior) Tr detected by
the inside air sensor is equal to or more than a predetermined
reference inside air temperature KTr (15.degree. C. in this
embodiment). In step S106, when the inside air temperature Tr is
determined to be equal to or more than the reference inside air
temperature KTr, the temperature of the vehicle interior is hot
enough for a general passenger not to feel unsatisfied with the
cold (hereinafter referred to as a "warm-up state"), and then the
operation proceeds to step S107 with the deffg kept to 1
(deffg=1).
[0263] In step S106, when the inside air temperature Tr is
determined not to be equal to or more than the reference inside air
temperature KTr, the inside air temperature Tr is not increased
until the warm-up state. In order to give the heating of the
vehicle interior a priority over the defrosting operation, the
operation returns again to step S102.
[0264] In step S107, it is determined whether or not the vehicle
speed during traveling is equal to or less than a predetermined
reference vehicle speed (20 km/h in this embodiment). In step S107,
when the vehicle speed is determined to be equal to or less than
the predetermined reference vehicle speed, like the first
embodiment, the defrosting can be effectively performed together
with the decrease in ram air pressure. Then, the operation proceeds
to an air conditioning mode changing control shown in step S200 of
FIG. 14 with deffg kept to 1 (deffg=1).
[0265] As can be seen from the above description, a control step
S100 of this embodiment serves as a control portion with a frost
formation determination portion for determining the frost formation
of the outdoor heat exchanger 16. More specifically, the control
steps S102 and S104 serve as the frost formation determination
portion.
[0266] Then, the air conditioning mode changing control to be
performed in step S200 will be described below using FIG. 16. The
air conditioning mode changing control is to be exercised when the
defrosting flag deffg is determined to be 1 by the defrosting
determination process in step S100.
[0267] In step S201, first, a control signal to be output to the
electric motor of the compressor 11 is determined such that the
compressor 11 does not exhibit the refrigerant discharge capacity,
that is, such that the compressor 11 is stopped. In the following
step S202, a control signal to be output to the blower 32 is
determined such that the air blowing capacity of the blower 32 is
decreased by a predetermined capacity value from the present
capacity.
[0268] In the following step S203, a suction port mode is set to
the inside air mode. That is, the ratio of introduction of inside
air to outside air is increased as compared to the state before the
transmission to the defrosting operation. In step S204, an air
outlet mode is set to the foot mode. That is, switching is
performed to the air outlet mode for blowing the air mainly from
the foot air outlet. Then, the operation proceeds to a defrosting
start completion control shown in step S300 of FIG. 14.
[0269] The defrosting start completion control executed in step
S300 will be described below using FIG. 17. In step S301, first, as
described in the first embodiment, the three-way valve 42 of the
coolant circulation circuit 40 is switched such that the coolant
flows into the radiator 43. Further, the coolant squeezing capacity
of the coolant pump 41 is maximized, the timer is actuated, and
then the operation proceeds to step S302.
[0270] In step S302, it is determined whether the vehicle speed
during traveling is equal to or less than a predetermined reference
vehicle speed (in this embodiment, 20 km/h). When the vehicle speed
is determined to be equal to or less than the reference vehicle
speed in step S302, the effective defrosting can be achieved, and
then the operation proceeds to step S303. When the vehicle speed is
determined not to be equal to or less than the reference vehicle
speed, the effective defrosting cannot be performed, and then the
operation proceeds to step S304.
[0271] In step S303, it is determined whether or not the elapsed
time of the defrosting operation exceeds a predetermined reference
defrosting time using the timer actuated in step S301. When the
elapsed time of the defrosting operation is determined to exceed
the reference defrosting time, the operation proceeds to step S304.
In step S304, at that time, the three-way valve 42 is switched such
that the coolant flows into the bypass passage 44.
[0272] Then, the coolant squeezing capacity of the coolant pump 41
is changed to become the same squeezing capacity as that before the
start of the defrosting operation, and the timer is reset.
Thereafter, the operation proceeds to an air conditioning mode
returning control shown in step S400 of FIG. 14. In the air
conditioning mode returning control in step S400, the blowing
capacity of the blower 32, the suction port mode, and the air
outlet mode are returned to the same levels as those before the
defrosting operation. Then, the operation proceeds to step
S500.
[0273] In step S500, it is determined whether stopping of the
vehicle system is requested or not. When the stopping of the
vehicle system is not required, the operation proceeds to step
S100. When the stopping of the vehicle system is required, the
control processing is stopped. The structures and operations of
other components of this embodiment are the same as those of the
first embodiment.
[0274] Thus, this embodiment can obtain the same effects as those
of the first embodiment. Additionally, in this embodiment, even
when the air conditioning controller stops the operation of the
compressor 11, and the indoor condenser 12 cannot exhibit the
heating capacity during the defrosting operation, the above vehicle
interior linkage control can be performed to prevent the passenger
from feeling unsatisfied with heating.
[0275] That is, in this embodiment, as described in the control
step S106, the defrosting operation is performed after the warm-up
state is achieved, which can prevent the passenger from feeling
unsatisfied with heating. As described in the control step S203,
during the defrosting operation, the suction port mode is changed
to the inside air mode. The inside air having a higher temperature
than the outside air is circulated and blown, which can also
prevent the passenger from feeling unsatisfied with heating.
[0276] As described in the control step S202, the blowing capacity
of the blower 32 is decreased in the defrosting operation, which
can prevent the passenger from feeling unsatisfied with heating
even when the temperature of air blown into the vehicle compartment
is decreased. At this time, as described in the control step S204,
the air outlet mode is set to the foot mode, which can effectively
prevent the passenger from feeling unsatisfied with the heating as
compared to the case where the air is blown toward the passenger's
face.
[0277] As can be seen from the above description, this embodiment
can be considered as the example of application of the heat pump
cycle 10 to the air conditioner) for a vehicle.
[0278] That is, this embodiment in one aspect includes a heat pump
cycle which has a compressor for compressing and discharging
refrigerant; a user-side heat exchanger (indoor condenser 12) for
exchanging heat between the refrigerant discharged from the
compressor and air blown into a vehicle interior; a decompression
device (fixed throttle 13 for heating) for decompressing the
refrigerant flowing from the user-side heat exchanger; an outdoor
heat exchanger for allowing the refrigerant decompressed by the
decompression device to exchange heat with outside air to evaporate
itself; a heat-dissipation heat exchanger (radiator 43) disposed in
a cooling fluid circulation circuit for circulating a cooling fluid
for cooling a vehicle-mounted device (electric motor MG for
traveling) generating heat in operation, and adapted to exchange
heat between the cooling fluid and outside air to dissipate heat
from the cooling fluid; a cooling fluid circuit for flowing the
cooling fluid into the heat-dissipation heat exchanger (43); and
cooling fluid circuit switching device (42) for performing
switching to another cooling fluid circuit for allowing the cooling
fluid to bypass the heat-dissipation heat exchanger (43). This
embodiment also includes inside air temperature detection portion
for detecting an inside air temperature in the vehicle interior;
and a frost formation determination portion for determining frost
formation at the outdoor heat exchanger. The outdoor heat exchanger
includes a refrigerant tube for flowing the refrigerant
decompressed by the decompression device. A heat-absorption air
passage for flowing outside air is formed around the refrigerant
tube. The heat-dissipation heat exchanger includes a cooling fluid
tube for flowing the cooling fluid. An heat-dissipation air passage
for flowing outside air is formed around the tubes for the cooling
fluid. The air passage for the heat absorption and the air passage
for the heat dissipation are provided with an outer fin that
enables the heat transfer between the refrigerant tube and the
cooling fluid tube, while promoting the heat exchange in both heat
exchangers. When the frost is determined to be formed at the
outdoor heat exchanger by the frost formation determination
portion, and an inside air temperature Tr of the vehicle interior
is equal to or more than a predetermined reference inside air
temperature KTr, then the cooling fluid circuit switching device
can perform switching to the cooling fluid circuit for flowing the
cooling fluid to the heat dissipation heat exchanger.
[0279] This embodiment in another aspect includes the above heat
pump cycle, a frost formation determination portion for determining
the frost formation of the outdoor heat exchanger, and a casing for
accommodating therein the user-side heat exchanger and for forming
an air passage. An inside/outside air switching device
(inside/outside air switch 33) is disposed in the casing to change
the ratio of introduction of the inside air to the outside air to
be introduced into the casing. When the frost is determined to be
formed in the outdoor heat exchanger by the frost formation
determination portion, the cooling fluid circuit switching device
performs switching to a cooling fluid circuit for flowing the
cooling fluid to the heat dissipation heat exchanger. When the
frost is determined to be formed in the outdoor heat exchanger by
the frost formation determination portion, the inside/outside air
switching device can increase the ratio of introduction of the
inside air to the outside air as compared to before transfer to the
defrosting operation.
[0280] This embodiment in another aspect includes the above heat
pump cycle, a frost formation determination portion for determining
the frost formation of the outdoor heat exchanger, and a casing for
accommodating therein the user-side heat exchanger and for forming
an air passage. An air outlet mode switching device is disposed in
the casing to switch among air outlet modes by changing
opening/closing states of a plurality of air outlets for blowing
the air into the vehicle interior. As the air outlet, a foot air
outlet is provided for blowing the air toward at least the foot of
a passenger. When the frost is determined to be formed at the
outdoor heat exchanger by the frost formation determination
portion, the cooling fluid circuit switching device performs
switching to a cooling fluid circuit for flowing the cooling fluid
to the heat dissipation heat exchanger. When the frost is
determined to be formed at the outdoor heat exchanger by the frost
formation determination portion, the air outlet mode switching
device can perform switching to the air outlet mode for blowing the
air from the foot air outlet.
[0281] This embodiment in another aspect includes the above heat
pump cycle, a frost formation determination portion for determining
the frost formation at the outdoor heat exchanger, a casing for
accommodating the user-side heat exchanger therein and for forming
an air passage, and blowing means (e.g., blower 32) disposed in the
casing for blowing the air toward the vehicle interior. When the
frost is determined to be formed at the outdoor heat exchanger by
the frost formation determination portion, the cooling fluid
circuit switching device performs switching to a cooling fluid
circuit for flowing the cooling fluid into the heat-dissipation
heat exchanger. When the frost is determined to be formed at the
outer heat exchanger by the frost formation determination portion,
the blower means can decreases its blowing capacity as compared to
before the determination of the frost formation.
[0282] This embodiment in another aspect includes the above heat
pump cycle, and a frost formation determination portion for
determining the frost formation of the outdoor heat exchanger. When
the vehicle speed of the traveling vehicle is equal to or less than
a predetermined reference vehicle speed, and the refrigerant
temperature on the outlet side of the outdoor heat exchanger is
equal to or less than 0.degree. C., the frost is determined to be
formed at the outdoor heat exchanger. When the frost is determined
to be formed at the outdoor heat exchanger by the frost formation
determination portion, the cooling fluid circuit switching device
can perform switching to the cooling fluid circuit for flowing the
cooling fluid to the heat-dissipation heat exchanger.
Eighth Embodiment
[0283] Although in the above first and seventh embodiments, the
operation of the compressor 11 is stopped during the defrosting
operation by way of example, in this embodiment as shown in FIG.
18, the cycle structure of the heat pump cycle 10 is changed to
achieve the heating of the vehicle interior, while performing the
defrosting operation like the third embodiment by way of example.
FIG. 18 is an entire configuration diagram of the heat pump cycle
10 during the defrosting operation in this embodiment,
corresponding to FIG. 2 of the first embodiment.
[0284] Specifically, this embodiment differs from the first
embodiment in that a variable throttle 83 for heating is employed
which is capable of changing the opening degree of throttle as a
decompression device for the heating operation. The variable
throttle 83 for heating includes a valve body whose throttle
opening degree is variable, and an electric actuator comprised of a
stepping motor for changing the throttle opening degree of the
valve body. The variable throttle 83 has its operation controlled
by a control signal output from the air conditioning
controller.
[0285] In this embodiment, the air conditioning controller controls
the valve opening degree of the variable throttle 83 for heating to
a predetermined opening degree in the heating operation and in the
waste heat collecting operation, and increases the valve opening
degree of the variable throttle 83 for heating in the defrosting
operation, as compared to the heating operation and the waste heat
collecting operation. Thus, in the defrosting operation, the
high-pressure refrigerant with a higher temperature discharged from
the compressor 11 is apt to flow into the outdoor heat exchanger 16
as compared to before the defrosting operation.
[0286] The structures and operations of other components of this
embodiment are the same as those of the first embodiment. Thus, in
the air conditioner 1 for the vehicle of this embodiment, the
throttle opening degree of the variable throttle 83 for heating is
increased in the defrosting operation, so that the high-pressure
refrigerant at a high temperature can flow into the outdoor heat
exchanger 16 to thereby promote the defrosting of the outdoor heat
exchanger 16. Further, during the defrosting operation, the heating
capacity of the indoor condenser 12 for heating the air can be
exhibited to perform heating of the vehicle interior.
[0287] As viewed from the flow direction of the outside air, the
positional relationship between a heat exchange region on a
refrigerant inlet side of the outdoor heat exchanger 16 and a heat
exchange region on a refrigerant outlet side thereof does not
change with respect to a heat exchanger region of the radiator 43,
which can suppress the large fluctuations in amount of the heat
transfer between the refrigerant flowing through the refrigerant
tubes 16a and the cooling fluid flowing through the cooling fluid
tubes 43a, like the third embodiment.
Ninth Embodiment
[0288] As shown in the entire configuration diagram of FIG. 19, in
this embodiment, the cycle structure of the heat pump cycle 10 is
changed to achieve the heating of the vehicle interior, while
performing the defrosting operation like the eighth embodiment by
way of example. FIG. 19 is an entire configuration diagram of the
heat pump cycle 10 in the defrosting operation according to this
embodiment, which corresponds to FIG. 2 of the first
embodiment.
[0289] Specifically, this embodiment differs from the first
embodiment in that an outflow rate adjustment valve 84 is added for
adjusting an outflow rate of the refrigerant flowing from the
outdoor heat exchanger 16. The outflow rate adjustment valve 84 has
the same basic structure as that of the variable throttle 83 for
the heating of the eighth embodiment, and thus is integral with the
refrigerant outlet of the outdoor heat exchanger 16.
[0290] In this embodiment, the air conditioning controller fully
opens the valve opening degree of the outflow rate adjustment valve
84 in the heating operation, the waste heat collection operation,
and the cooling operation, and reduces the valve opening degree of
the outflow rate adjustment valve 84 in the defrosting operation as
compared to in the heating operation, the waste heat collecting
operation, and the cooling operation. Thus, in the defrosting
operation, an inflow rate of the refrigerant flowing into the
outdoor heat exchanger 16 is decreased as compared to before the
transfer to the defrosting operation. The structures and operations
of other components of this embodiment are the same as those of the
first embodiment.
[0291] In the air conditioner 1 for a vehicle of this embodiment,
the valve opening degree of the outflow rate adjustment valve 84 is
decreased in the defrosting operation, so that the inflow rate of
the refrigerant flowing into the outdoor heat exchanger 16 can be
decreased, which can provide the same effects as those of the
eighth embodiment.
[0292] Since the outflow rate adjustment valve 84 is integrally
structured with a refrigerant outlet of the outdoor heat exchanger
16, the volume of the refrigerant passage leading from the
discharge port of the compressor 11 to the inlet side of the outlet
rate adjustment valve 84 can be decreased to thereby quickly
decrease the flow rate of the refrigerant flowing into the outdoor
heat exchanger 16.
Tenth and Eleventh Embodiments
[0293] In the above third, eighth, and ninth embodiments, the
outdoor heat exchanger 16 exhibits the heating capacity to achieve
the heating of the vehicle interior without stopping the operation
of the compressor 11 in the defrosting operation, by way of
example. In the ninth embodiment, as shown in FIG. 20, a PTC heater
85 is disposed in the casing 31 of the indoor air conditioning unit
30, and serves as a heating element for generating heat by being
supplied with power.
[0294] The PTC heater 85 is disposed on the downstream side of the
air flow of the indoor condenser 12, and generates heat by being
supplied with power from the air conditioning controller in the
defrosting operation. Thus, even when the air conditioning
controller stops the operation of the compressor 11 during the
defrosting operation, the PTC heater 85 can function as an
auxiliary heater to heat the air, thereby achieving the heating of
the vehicle interior.
[0295] In the eleventh embodiment, as shown in FIG. 21, a heater
core 86 is provided for exchanging heat between the engine coolant
as a heat fluid, and the air. The heater core 86 has the same basic
structure as that of the heater core 63 of the second embodiment.
The heater core 86 is disposed on the downstream side of the air
flow of the indoor condenser 12 to allow the engine coolant to flow
thereinto during the defrosting operation.
[0296] Thus, even when the air conditioning controller stops the
operation of the compressor 11 during the defrosting operation, the
heater core 86 can function as an auxiliary heater to heat the air,
thereby achieving the heating of the vehicle interior. The heat
fluid serving as a heat source for heating the air at the heater
core 86 is not limited to the engine coolant, but may be coolant or
the like for cooling the vehicle-mounted devices generating heat in
operation, such as the electric motor MG for traveling, or an
inverter.
[0297] Alternatively, both the PTC heater 85 of the tenth
embodiment and the heater core 86 of the eleventh embodiment may be
disposed on the downstream side of the air flow of the indoor
condenser 12 to serve as the auxiliary heater. FIGS. 20 and 21 are
the entire configuration diagrams of the heat pump cycle 10 in the
defrosting operation according to the ninth and eleventh
embodiment, respectively, and correspond to FIG. 2 of the first
embodiment.
Other Embodiments
[0298] The present invention is not limited to the above
embodiments, and various modifications and changes can be made to
the above embodiments without departing from the scope of the
invention as follows.
[0299] (1) In the above embodiments, the vehicle-mounted device
(external heat source) generating heat in operation is the electric
motor MG for traveling, by way of example, but the external heat
source is not limited thereto. For example, when the heat pump
cycle 10 is applied to the air conditioner 1 for the vehicle, an
engine or an electric device, such as an inverter, for supplying
power to the electric motor MG for traveling can be used as the
external heat source.
[0300] In using the engine as the external heat source, the heat
contained not only in the engine coolant, but also in engine
exhaust gas may be used for defrosting. Further, in applying the
heat pump cycle 10 to a stationary air conditioner, a cool storage,
a cooling and heating device for a vending machine, and the like,
the engine, the electric motor, and other electric devices which
serve as the driving source for the compressor of the heat pump
cycle 10 can be used as the external heat source.
[0301] (2) In the above embodiments, the electric three-way valve
42 is employed as circuit switching device for switching among the
cooling fluid circuits of the coolant circulation circuit 40, but
the circuit switching device is not limited thereto. For example, a
thermostat valve may be used. Thermostat valve is a cooling fluid
temperature-responsive valve comprised of a mechanical mechanism
that opens and closes a cooling fluid passage by displacing a valve
body using a thermo wax (temperature sensing member) whose volume
is changed by the temperature. Thus, the use of thermostat valve
can also remove the coolant temperature sensor 52.
[0302] (3) In the above embodiments, the refrigerant tubes 16a of
the outdoor heat exchanger 16, the cooling fluid tubes 43a of the
radiator 43, and the outer fins 50 are formed of an aluminum alloy
(metal) and bonded together by brazing. Obviously, the outer fins
50 may be formed of other materials with excellent heat
conductivity (for example, a carbon nanotube or the like), and
these elements may be bonded together with other bonding means,
such as an adhesive.
[0303] (4) In the above embodiments, in the normal heating
operation, switching is performed to a cooling fluid circuit for
allowing the coolant to bypass the radiator 43, which stores the
heat dissipated from the electric motor MG for traveling in the
coolant. Alternatively or additionally, a heat storage case (heat
storing device) for accommodating a heat storing material, such as
paraffin, may be disposed in the coolant circulation circuit 40,
whereby the heat dissipated from the electric motor MG for
traveling may be stored in the heat storage case in the normal
heating operation.
[0304] Alternatively or additionally, a heating element (for
example, PTC heater) that generates heat by being supplied with
power may be disposed in the coolant circulation circuit 40, so
that the heat dissipated from the heating element may be stored in
the coolant in the normal heating operation. Alternatively, the
heat dissipated from at least one of the vehicle-mounted device and
the heating element that generates heat in the operation of the
electric motor MG for traveling and the like may be stored in the
coolant. At this time, the amount of heat generated in the heating
element is desirably controlled to increase with decreasing outside
air temperature so as to avoid the unnecessary power
consumption.
[0305] (5) In the above first embodiment, when the vehicle speed is
equal to or less than the predetermined reference vehicle speed (20
km/h in this embodiment) and the refrigerant temperature Te on the
outlet side of the outdoor heat exchanger 16 is equal to or less
than 0.degree. C., the frost formation determination portion is
used to determine whether the frost is formed at the outdoor heat
exchanger 16, by way of example. However, the determination
conditions for the frost formation are not limited thereto.
[0306] For example, temperature detection portion for detecting the
temperature of the outer fin 50 of the outdoor heat exchanger 16
may be provided, and when the temperature detected by the
temperature detection portion is equal to or less than the
predetermined frost formation reference temperature (for example,
-5.degree. C.), the frost may be determined to be formed.
[0307] (6) In the above embodiments, the means for stopping the
operation of the blower fan 17 in the defrosting operation is used
to decrease the volume of outside air flowing into the
heat-absorption air passage 16b and the heat-dissipation air
passage 43b, by way of example. Regardless of the normal operation
and the defrosting operation, when the compressor 11 is stopped,
the blowing capacity of the blower fan 17 may be increased until a
predetermined time has elapsed. Thus, when the compressor 11 is
stopped, the blowing capacity of the blower fan 17 can be
increased, so that the temperature of the outdoor heat exchanger 16
can be quickly increased to the same level as the outside air
temperature.
[0308] (7) The structures described in the above respective
embodiments may be applied to other embodiments. For example, the
vehicle indoor linkage control described in the seventh embodiment
may be executed in the air conditioner for a vehicle to which the
heat pump cycle 10 of each of the second to fifth, and eighth to
eleventh embodiments is applied.
[0309] For example, when the vehicle interior linkage control of
the seventh embodiment is applied to the heat pump cycle 10 of the
third embodiment, the air conditioning controller may open the
opening/closing valve 15c in the air conditioning mode changing
control in the control step S200 without stopping the operation of
the compressor 11. When applied to the fourth embodiment, the
opening/closing valve 15a and the opening/closing valve 15c may be
opened by air conditioning mode changing control in the control
step S200.
[0310] Likewise, when applied to the eighth embodiment, the valve
opening degree of the variable throttle 83 for heating may be
reduced in the air conditioning mode changing control in the
control step S200. When applied to the ninth embodiment, the valve
opening degree of the outflow rate adjustment valve 84 may be
reduced in the air conditioning mode changing control in the
control step S200.
[0311] (8) Although in the above embodiments, normal flon-based
refrigerant is used as the refrigerant, by way of example, the
refrigerant is not limited thereto. Natural refrigerant, such as
carbon dioxide, and a carbon-hydride refrigerant and the like may
be used. Further, the heat pump cycle 10 may form a supercritical
refrigeration cycle in which the pressure of refrigerant discharged
from the compressor 11 is equal to or higher than the critical
pressure of the refrigerant.
* * * * *