JP5984544B2 - Air conditioner for vehicles - Google Patents

Description

  The present invention relates to a vehicle air conditioner applicable to, for example, an electric vehicle.

  Conventionally, this type of vehicle air conditioner includes a compressor that compresses and discharges a refrigerant, an indoor heat exchanger provided in a vehicle interior, and an outdoor heat exchanger provided outside the vehicle interior. Things are known. In this vehicle air conditioner, the refrigerant discharged from the compressor flows into the indoor heat exchanger to dissipate heat, and the refrigerant flowing through the indoor heat exchanger flows into the outdoor heat exchanger through the expansion means to absorb heat. Then, the refrigerant is discharged from the outdoor heat exchanger, and the heating operation is performed by causing the compressor to suck the refrigerant.

  In the vehicle air conditioner, frost formation may occur in the outdoor heat exchanger when the heating operation is performed in an environment where the temperature outside the vehicle compartment is low (for example, 0 degrees Celsius or less). In the heating operation, when frost is generated in the outdoor heat exchanger, the heat absorption amount in the outdoor heat exchanger is insufficient and the heating capacity is reduced. For this reason, at the time of heating operation, a defrosting operation may be required in order to remove the frost adhering to the outdoor heat exchanger.

  In the defrosting operation, the high-temperature refrigerant discharged from the compressor is caused to flow into the outdoor heat exchanger, thereby melting the frost adhering to the outdoor heat exchanger. However, when performing a defrosting operation while the vehicle is running, low temperature air continues to hit the frost attached to the outdoor heat exchanger, making it difficult for the frost to melt and removing the frost attached to the outdoor heat exchanger. Difficult to do.

  Therefore, in the vehicle air conditioner, a movable louver is provided outside the outdoor heat exchanger so that the traveling wind does not directly hit the outdoor heat exchanger by the movable louver during the defrosting operation and adheres to the outdoor heat exchanger. The frost that has been removed is efficiently removed (see, for example, Patent Document 1).

JP-A-7-55296

  In the vehicle air conditioner equipped with the movable louver, the number of parts increases, such as the movable louver and the electric motor for driving the movable louver, resulting in an increase in manufacturing cost and a large space occupied in the engine room. Therefore, it is difficult to install the air conditioner on a small vehicle.

  An object of the present invention is to provide a vehicle air conditioner that can reliably remove frost attached to an outdoor heat exchanger without increasing the number of parts and occupied space.

  In order to achieve the above object, the present invention provides a compressor that compresses and discharges a refrigerant, a radiator that radiates heat from the refrigerant, a heat absorber that absorbs heat from the refrigerant, and an outdoor heat exchanger that radiates or absorbs heat from the refrigerant. The refrigerant discharged from the compressor flows into the radiator to dissipate heat, and at least a part of the refrigerant flowing through the radiator flows into the outdoor heat exchanger through the expansion valve to absorb heat, and flows through the outdoor heat exchanger A refrigerant circuit for heating that causes the refrigerant to flow into the accumulator and suck the refrigerant flowing out of the accumulator into the compressor, a valve opening adjustment mechanism that adjusts the valve opening of the expansion valve, a refrigerant outflow side of the outdoor heat exchanger, An on-off valve that opens and closes the refrigerant flow path between the refrigerant inflow side of the accumulator, frost determination determining means for determining whether or not a condition for causing frost formation in the outdoor heat exchanger, and frost formation during the heating operation Outdoor heat exchanger by judging means When it is determined that frost formation occurs, the valve opening adjustment mechanism makes the valve opening of the expansion valve larger than the valve opening of the expansion valve during heating operation, thereby increasing the valve opening of the expansion valve. Hot gas defrosting means for closing the on-off valve later.

  As a result, the refrigerant is stored in a liquid state in the accumulator by making the valve opening of the expansion valve larger than the valve opening of the expansion valve during heating operation. By closing, the liquid refrigerant stored in the accumulator is vaporized and flows into the outdoor heat exchanger, so that the inside of the outdoor heat exchanger becomes a high-temperature and high-pressure state and increases the heat radiation amount in the outdoor heat exchanger. Is possible.

  According to the present invention, the amount of heat radiation in the outdoor heat exchanger can be increased with the inside of the outdoor heat exchanger in a high-temperature and high-pressure state, so that frost attached to the outdoor heat exchanger can be reliably removed. .

It is a schematic block diagram of the vehicle air conditioner which shows 1st Embodiment of this invention. It is a graph which shows the relationship between the rotation position of the stepping motor of a 1st control valve, and valve opening. It is a schematic block diagram of the air conditioning apparatus for vehicles which shows a cooling operation and a dehumidification cooling operation. It is a schematic block diagram of the vehicle air conditioner which shows heating operation. It is a schematic block diagram of the vehicle air conditioner which shows 1st dehumidification heating operation. It is a schematic block diagram of the air conditioning apparatus for vehicles which shows 2nd dehumidification heating operation. It is a timing chart of hot gas defrosting operation. It is a timing chart of a reverse cycle defrost operation. It is a flowchart which shows a defrost operation control process. It is a schematic block diagram of the vehicle air conditioner which shows 2nd Embodiment of this invention. It is a schematic block diagram of the vehicle air conditioner which shows a reverse cycle defrost driving | operation.

  1 to 9 show a first embodiment of the present invention.

  As shown in FIG. 1, the vehicle air conditioner of the present invention includes an air conditioning unit 10 provided in a vehicle interior, and a refrigerant circuit 20 configured across the vehicle interior and the exterior of the vehicle interior.

  The air conditioning unit 10 has an air flow passage 11 for circulating air supplied into the vehicle interior. On one end side of the air flow passage 11, an outside air intake port 11 a for allowing the air outside the vehicle interior to flow into the air flow passage 11, an inside air intake port 11 b for allowing the air inside the vehicle interior to flow into the air flow passage 11, Is provided. Further, on the other end side of the air flow passage 11, a foot outlet 11 c that blows out air flowing through the air flow passage 11 toward the feet of the passengers in the passenger compartment, and air flowing through the air flow passage 11 are supplied to the vehicle. A vent outlet 11d that blows out toward the upper body of the passenger in the room, and a differential outlet 11e that blows out the air flowing through the air flow passage 11 toward the surface of the vehicle windshield toward the vehicle interior side. ing.

  An indoor blower 12 such as a sirocco fan for circulating air from one end side to the other end side of the air flow passage 11 is provided on one end side in the air flow passage 11.

  On one end side of the air flow passage 11, there is provided an inlet switching damper 13 that can open one of the outside air inlet 11 a and the inside air inlet 11 b and close the other. When the inside air suction port 11b is closed by the suction port switching damper 13 and the outside air suction port 11a is opened, an outside air supply mode in which air flows from the outside air suction port 11a into the air flow passage 11 is set. Further, when the outside air suction port 11a is closed by the suction port switching damper 13 and the inside air suction port 11b is opened, the inside air circulation mode in which air flows from the inside air suction port 11b into the air flow passage 11 is set. Further, when the suction port switching damper 13 is positioned between the outside air suction port 11a and the inside air suction port 11b, and the outside air suction port 11a and the inside air suction port 11b are opened, the outside air suction port 11a by the suction port switching damper 13 is opened. And the inside / outside air suction mode in which air flows into the air flow passage 11 from the outside air suction port 11a and the inside air suction port 11b at a ratio corresponding to the respective opening ratios of the inside air suction port 11b.

  The outlet switching dampers 13b, 13c, and 13d for opening and closing the outlets 11c, 11d, and 11e are provided at the foot outlet 11c, the vent outlet 11d, and the differential outlet 11e on the other end side of the air flow passage 11, respectively. Is provided. The outlet switching dampers 13b, 13c, and 13d are configured to be interlocked by a link mechanism (not shown). Here, when the foot outlet 11c is opened by the outlet switching dampers 13b, 13c, and 13d, the vent outlet 11d is closed, and the differential outlet 11e is slightly opened, the air flowing through the air flow passage 11 is reduced. Most of the air is blown from the foot outlet 11c and the remaining air is blown from the differential outlet 11e. When the foot outlet 11c and the differential outlet 11e are closed by the outlet switching dampers 13b, 13c, and 13d and the vent outlet 11d is opened, all of the air flowing through the air flow passage 11 is vented 11d. It becomes the vent mode blown out from. Further, when the foot outlet 11c and the vent outlet 11d are opened by the outlet switching dampers 13b, 13c, and 13d and the differential outlet 11e is closed, the air flowing through the air flow passage 11 is moved to the foot outlet 11c and the vent. It becomes the bilevel mode which blows off from the blower outlet 11d. When the foot outlet 11c and the vent outlet 11d are closed by the outlet switching dampers 13b, 13c, and 13d and the differential outlet 11e is opened, the air flowing through the air flow passage 11 is blown out from the differential outlet 11e. It becomes the differential mode. When the vent outlet 11d is closed by the outlet switching dampers 13b, 13c, and 13d and the foot outlet 11c and the differential outlet 11e are opened, the air flowing through the air flow passage 11 is transferred to the foot outlet 11c and the differential outlet 11c. It becomes the differential foot mode which blows off from the blower outlet 11e. In the air flow passage 11, the foot outlet 11c, the vent outlet 11d, the heat absorber and the radiator described later, the temperature of the air blown from the foot outlet 11c is blown out from the vent outlet 11d in the bi-level mode. The positional relationship and the structure are such that a temperature difference that is higher than the temperature of the air is generated.

  The air flow passage 11 on the downstream side in the air flow direction of the indoor blower 12 is provided with a heat absorber 14 for cooling and dehumidifying the air flowing through the air flow passage 11. A heat radiator 15 for heating the air flowing through the air flow passage 11 is provided in the air flow passage 11 on the downstream side in the air flow direction of the heat absorber 14. The heat absorber 14 and the heat radiator 15 are heat exchangers including fins and tubes for exchanging heat between the refrigerant flowing through the interior and the air flowing through the air flow passage 11.

  The air flow path 11 between the heat absorber 14 and the heat radiator 15 is provided with an air mix damper 16 for adjusting a ratio of air heated by the heat radiator 15 flowing through the air flow path 11. By moving the air mix damper 16 in the direction of closing the upstream side of the radiator 15 in the air flow passage 11, the ratio of the air to be heat exchanged in the radiator 15 is reduced, and other than the radiator 15 in the air flow passage 11. By moving to the partial side, the proportion of air that exchanges heat in the radiator 15 increases. The air mix damper 16 closes the upstream side of the radiator 15 in the air flow passage 11 and opens the portion other than the radiator 15 so that the opening degree becomes 0%, and the upstream side of the radiator 15 in the air flow passage 11. Is opened and the opening is 100% with the portion other than the radiator 15 closed.

  The refrigerant circuit 20 includes the heat absorber 14, the radiator 15, a compressor 21 for compressing the refrigerant, an outdoor heat exchanger 22 for exchanging heat between the refrigerant and air outside the passenger compartment, the radiator 15, and outdoor heat. An internal heat exchanger 23 for exchanging heat between at least the refrigerant flowing out of the radiator 15 and the refrigerant flowing out of the heat absorber 14 of the exchanger 22, flows into the outdoor heat exchanger 22 during heating operation and first dehumidifying heating operation. An expansion means for decompressing the refrigerant and a condensation pressure adjusting means for controlling the condensation pressure of the refrigerant in the radiator 15 during the dehumidifying and cooling operation, and switching the refrigerant flow path to the expansion means side or the condensation pressure adjustment means side A first control valve 24, a second control valve 25 for adjusting the evaporation pressure of the refrigerant in the heat absorber 14, a first electromagnetic valve 26a, a second electromagnetic valve 26b, a third electromagnetic valve 26c, 1 to 2 Check valves 27a and 27b, an expansion valve 28, an accumulator 29 for separating the gaseous refrigerant and the liquid refrigerant and preventing the liquid refrigerant from being sucked into the compressor 21, and these are copper pipes Or connected by an aluminum tube.

  Specifically, the refrigerant flow path 20 a is provided by connecting the refrigerant inflow side of the radiator 15 to the refrigerant discharge side of the compressor 21. Further, a refrigerant flow passage 20 b is provided on the refrigerant outflow side of the radiator 15 by connecting the refrigerant inflow side of the first control valve 24. A refrigerant flow passage 20c is provided on the refrigerant outflow side of the first control valve 24 on the expansion means side by connecting one end side of the outdoor heat exchanger 22. A first check valve 27a is provided in the refrigerant flow passage 20c. Further, the refrigerant flow passage 20d is provided on the refrigerant outflow side of the first control valve 24 on the side of the condensation pressure adjusting means by connecting the other end side of the outdoor heat exchanger 22. The refrigerant heat passage 20e is provided on the other end side of the outdoor heat exchanger 22 by connecting the refrigerant suction side of the compressor 21 in parallel with the refrigerant flow passage 20d. The refrigerant flow passage 20e is provided with a first electromagnetic valve 26a and an accumulator 29 in order from the upstream side in the refrigerant flow direction. The refrigerant flow passage 20b is provided with a refrigerant flow passage 20f by connecting the high-pressure refrigerant inflow side of the internal heat exchanger 23 to the refrigerant flow passage 20b. A second electromagnetic valve 26b is provided in the refrigerant flow passage 27f. A refrigerant flow passage 20 g is provided on the high-pressure refrigerant outflow side of the internal heat exchanger 23 by connecting the refrigerant inflow side of the heat absorber 14. An expansion valve 28 is provided in the refrigerant flow passage 20g. A refrigerant flow passage 20 h is provided on the refrigerant outflow side of the heat absorber 14 by connecting the low-pressure refrigerant inflow side of the internal heat exchanger 23. A second control valve 25 is provided in the refrigerant flow passage 20h. A refrigerant flow passage 20 i is provided on the low-pressure refrigerant outflow side of the internal heat exchanger 23 by connecting the first electromagnetic valve 26 a of the refrigerant flow passage 20 e and the accumulator 29. A refrigerant flow passage 20j is provided on one end side of the outdoor heat exchanger 22 in parallel with the refrigerant flow passage 20c by connecting the downstream side of the second electromagnetic valve 26b of the refrigerant flow passage 20f in the refrigerant flow direction. Yes. The refrigerant flow passage 20j is provided with a third electromagnetic valve 26c and a second check valve 27b in order from the upstream side in the refrigerant flow direction.

  The compressor 21 and the outdoor heat exchanger 22 are disposed in an engine room outside the vehicle compartment. The compressor 21 is driven by an electric motor, and the rotation speed can be adjusted by inverter control.

  The outdoor heat exchanger 22 is a heat exchanger composed of fins, tubes, and the like for exchanging heat between the refrigerant circulating inside and the air outside the vehicle compartment. When the outdoor heat exchanger 22 functions as a heat absorber, the refrigerant flows from one end side of the refrigerant flow path, and when the outdoor heat exchanger 22 functions as a radiator, the refrigerant flows from the other end side of the refrigerant flow path. On one end side of the refrigerant flow path of the outdoor heat exchanger 22, a gas-liquid separation unit 22a capable of storing a liquid refrigerant when functioning as a radiator, and a liquid refrigerant flowing out of the gas-liquid separation unit 22a are supercooled. And a supercooling portion 22b for providing the above state. The outdoor heat exchanger 22 is provided with an outdoor blower 22c for exchanging heat between air outside the passenger compartment and the refrigerant when the vehicle is stopped.

  The first control valve 24 has a stepping motor as a valve opening adjustment mechanism for switching the refrigerant flow path to the expansion means side or the condensation pressure adjustment means side and adjusting the opening degree of each refrigerant flow path. Yes. As shown in FIG. 2, the first control valve 24 switches the refrigerant passage and the opening degree of each refrigerant passage by driving the stepping motor.

  The expansion valve 28 is a temperature expansion valve that can adjust the valve opening according to the temperature of the refrigerant flowing out of the heat absorber 14. As the temperature expansion valve, for example, an outflow refrigerant passage through which the refrigerant flowing out from the heat absorber flows, a temperature sensing rod for detecting the temperature through the outflow refrigerant passage, and a diaphragm for moving the valve body, An integrally formed box-type temperature expansion valve is used.

  Further, as shown in FIG. 1, the vehicle air conditioner includes a controller 30 for performing control to set the temperature and humidity in the passenger compartment to the set temperature and the set humidity.

  The controller 30 has a CPU, ROM, and RAM. When the controller 30 receives an input signal from a device connected to the input side, the CPU reads a program stored in the ROM based on the input signal, and stores a state detected by the input signal in the RAM. The output signal is transmitted to a device connected to the output side.

  The indoor blower 12, the compressor 21, the first control valve 24, the first electromagnetic valve 26a, and the third electromagnetic valve 26c are connected to the output side of the controller 30. Further, a pressure sensor 31 for detecting the pressure of the refrigerant discharged from the compressor 21 is connected to the input side of the controller 30.

  In the vehicle air conditioner configured as described above, a cooling operation, a dehumidifying and cooling operation, a heating operation, a first dehumidifying and heating operation, and a second dehumidifying and heating operation are performed. Hereinafter, each operation will be described.

In the cooling operation and the dehumidifying and cooling operation, in the refrigerant circuit 20, the refrigerant flow path of the first control valve 24 is set on the condensation pressure adjusting means side, the third electromagnetic valve 26c is opened, and the first and second electromagnetic valves 26a. 26b are closed and the compressor 21 is operated.
As a result, the refrigerant discharged from the compressor 21 is, as shown in FIG. 3, the refrigerant flow passage 20a, the radiator 15, the refrigerant flow passages 20b and 20d, the outdoor heat exchanger 22, the refrigerant flow passages 20j and 20f, The high pressure side of the heat exchanger 23, the refrigerant flow passage 20 g, the heat absorber 14, the refrigerant flow passage 20 h, the low pressure side of the internal heat exchanger 23, and the refrigerant flow passages 20 i and 20 e flow in order and are sucked into the compressor 21. In the cooling operation, the refrigerant flowing through the refrigerant circuit 20 dissipates heat in the outdoor heat exchanger 22 and absorbs heat in the heat absorber 14. When the air mix damper 16 is opened as shown in the one-dot chain line in FIG. 3 in the dehumidifying and cooling operation, the refrigerant flowing through the refrigerant circuit 20 also radiates heat in the radiator 15. Moreover, the refrigerant | coolant which distribute | circulates the outdoor heat exchanger 22 will be in the state of a supercooling by flowing through the gas-liquid separation part 22a and the supercooling part 22b, and will flow into the refrigerant | coolant flow path 20j.

  At this time, in the air-conditioning unit 10 in the cooling operation, the air in the air flow passage 11 circulated by operating the indoor blower 12 is cooled by exchanging heat with the refrigerant in the heat absorber 14, and the temperature in the vehicle interior is set as a target. In order to obtain the temperature Tset, the air is blown into the vehicle interior as the target air temperature TAO, which is the temperature of the air to be blown out from the air outlets 11c, 11d, 11e.

  The target blowing temperature TAO is calculated based on the detected environmental conditions and the target set temperature Tset by detecting environmental conditions such as the temperature Tam outside the passenger compartment, the temperature Tr inside the passenger compartment, and the amount of solar radiation Ts.

  Further, in the air conditioning unit 10 during the dehumidifying and cooling operation, the air in the air flow passage 11 circulated by operating the indoor fan 12 is dehumidified by being cooled by exchanging heat with the refrigerant that absorbs heat in the heat absorber 14. . The air dehumidified in the heat absorber 14 is heated by exchanging heat with the refrigerant that dissipates heat in the radiator 15 and is blown into the passenger compartment as air at the target blowing temperature TAO.

In the heating operation, in the refrigerant circuit 20, the refrigerant flow path of the first control valve 24 is set on the expansion means side, the first electromagnetic valve 26a is opened, and the second and third electromagnetic valves 26b and 26c are closed, The compressor 21 is operated.
As a result, the refrigerant discharged from the compressor 21 flows in the order of the refrigerant flow passage 20a, the radiator 15, the refrigerant flow passages 20b and 20c, the outdoor heat exchanger 22, and the refrigerant flow passage 20e as shown in FIG. And sucked into the compressor 21. The refrigerant flowing through the refrigerant circuit 20 dissipates heat in the radiator 15 and absorbs heat in the outdoor heat exchanger 22.

  At this time, in the air conditioning unit 10, the air in the air flow passage 11 circulated by operating the indoor fan 12 is heated by exchanging heat with the refrigerant in the radiator 15 without exchanging heat with the refrigerant in the heat absorber 14. Then, the air becomes the target blowing temperature TAO and is blown into the passenger compartment.

In the first dehumidifying and heating operation, in the refrigerant circuit 20, the refrigerant flow path of the first control valve 24 is set on the expansion means side, the first and second electromagnetic valves 26a and 26b are opened, and the third electromagnetic valve 26c is set. The compressor 21 is closed and the compressor 21 is operated.
Thereby, as shown in FIG. 5, the refrigerant | coolant discharged from the compressor 21 distribute | circulates the refrigerant | coolant flow path 20a, the heat radiator 15, and the refrigerant | coolant flow path 20b in order. A part of the refrigerant flowing through the refrigerant flow passage 20b flows through the refrigerant flow passage 20c, the outdoor heat exchanger 22, and the refrigerant flow passage 20e in this order, and is sucked into the compressor 21. Other refrigerants flowing through the refrigerant flow passage 20b include the refrigerant flow passage 20f, the high pressure side of the internal heat exchanger 23, the refrigerant flow passage 20g, the heat absorber 14, the refrigerant flow passage 20h, and the low pressure side of the internal heat exchanger 23. Then, the refrigerant flow passages 20i and 20e are circulated in this order and sucked into the compressor 21. The refrigerant flowing through the refrigerant circuit 20 radiates heat in the radiator 15 and absorbs heat in the heat absorber 14 and the outdoor heat exchanger 22.

  At this time, in the air conditioning unit 10, the air in the air flow passage 11 circulated by operating the indoor blower 12 is dehumidified by being cooled by heat exchange with the refrigerant in the heat absorber 14. The air dehumidified in the heat absorber 14 is heated when a part of the air exchanges heat with the refrigerant in the radiator 15, and is blown into the vehicle interior as air at the target blowing temperature TAO.

In the second dehumidifying heating operation, the refrigerant circuit 20 closes the refrigerant flow path of the first control valve 24, opens the second electromagnetic valve 26b, closes the first and third electromagnetic valves 26a, 26c, and compresses them. The machine 21 is operated.
Thereby, the refrigerant discharged from the compressor 21 is, as shown in FIG. 6, the refrigerant flow passage 20a, the radiator 15, the refrigerant flow passages 20b and 20f, the high-pressure side of the internal heat exchanger 23, the refrigerant flow passage 20g, The heat absorber 14, the refrigerant flow passage 20 h, the low-pressure side of the internal heat exchanger 23, and the refrigerant flow passages 20 i and 20 e are circulated in this order and sucked into the compressor 21. The refrigerant flowing through the refrigerant circuit 20 dissipates heat in the radiator 15 and absorbs heat in the heat absorber 14.

  At this time, in the air conditioning unit 10, the air in the air flow passage 11 circulated by operating the indoor blower 12 is cooled by exchanging heat with the refrigerant in the heat absorber 14 as in the first dehumidifying heating operation. Is dehumidified. The air dehumidified in the heat absorber 14 is heated when a part of the air exchanges heat with the refrigerant in the radiator 15, and is blown into the vehicle interior at the target blowing temperature TAO.

  When the auto air conditioner switch is set to ON, the controller 30 performs the cooling operation, the dehumidifying and cooling operation, the heating operation, the first dehumidifying and heating operation, the second dehumidifying and heating operation, the temperature Tam outside the vehicle, Switching is performed based on environmental conditions such as the indoor temperature Tr, the humidity outside the passenger compartment, the humidity Th in the passenger compartment, and the amount of solar radiation Ts.

  Moreover, the controller 30 switches the mode of the blower outlets 11c, 11d, and 11e by the blower outlet switching dampers 13b, 13c, and 13d. The controller 30 adjusts the opening degree of the air mix damper 16 so that the temperature of the air blown from the blowout ports 11c, 11d, and 11e becomes the target blowout temperature TAO.

  Further, the controller 30 performs switching between the foot mode, the vent mode, and the bi-level mode in each operation in accordance with the target blowing temperature TAO. Specifically, the controller 30 sets the foot mode when the target blowing temperature TAO is high, such as 40 ° C. or higher. Further, the controller 30 sets the vent mode when the target blowing temperature TAO becomes a low temperature such as less than 25 ° C., for example. Further, the controller 30 sets the bi-level mode when the target blowing temperature TAO is a temperature between the target blowing temperature TAO for which the foot mode is set and the target blowing temperature TAO for which the vent mode is set.

  Further, when the temperature of the air outside the passenger compartment is lowered during the heating operation (for example, 0 degrees Celsius or less), frost formation may occur in the outdoor heat exchanger 22. In this case, the vehicle air conditioner performs a defrosting operation for removing frost attached to the outdoor heat exchanger 22. In the defrosting operation, the refrigerant discharged from the compressor 21 is allowed to flow into the outdoor heat exchanger 22 without being depressurized on the expansion means side of the first control valve 24, thereby melting the frost attached to the outdoor heat exchanger 22. This is performed by one of two methods: a hot gas defrosting operation and a reverse cycle defrosting operation in which the frost adhering to the outdoor heat exchanger 22 is melted by switching the refrigerant circuit 20 to the cooling operation.

  The hot gas defrosting operation switches the operation of the indoor blower 12, the compressor 21, the first control valve 24, and the first electromagnetic valve 26a as shown in the timing chart of FIG. 7 while the heating operation is performed. Is done by.

  Specifically, first, the rotation speed of the compressor 21 is fixed to a predetermined rotation speed (for example, 4000 rpm), and the refrigerant flow path of the first control valve 24 is fixed to the maximum opening on the expansion means side, and the indoor blower 12 is stopped. Next, the first electromagnetic valve 26a is closed after a predetermined time has elapsed (for example, 20 seconds later) after the refrigerant flow path of the first control valve 24 is fixed at the maximum opening on the expansion means side. Finally, after a predetermined time has elapsed since the first electromagnetic valve 26a was closed (for example, after 10 seconds), the first electromagnetic valve 26a is opened, the rotational speed of the compressor 21 is fixed, and the indoor fan 12 The stopped state and the fixed state of the maximum opening degree of the refrigerant flow path of the first control valve 24 on the expansion means side are released to end the hot gas defrosting operation.

  In the hot gas defrosting operation, the refrigerant discharged from the compressor 21 flows through the same flow path as in the heating operation of FIG. Since the refrigerant flowing through the refrigerant circuit 20 is not decompressed by the first control valve 24, the refrigerant is also radiated and liquefied in the outdoor heat exchanger 22, and the liquefied refrigerant is stored in the accumulator 29. Thereby, in the refrigerant circuit 20, since the flow volume of a refrigerant | coolant reduces, the pressure of the refrigerant | coolant in the outdoor heat exchanger 22 becomes low.

  When the first electromagnetic valve 26a is closed when the pressure of the refrigerant in the outdoor heat exchanger 22 is low and the liquid refrigerant is stored in the accumulator 29, the refrigerant flow path between the compressor 21 and the first electromagnetic valve 26a. 20 e becomes a low pressure, and the liquid refrigerant stored in the accumulator 29 is vaporized and discharged from the compressor 21. At this time, in the refrigerant circuit 20, since the first electromagnetic valve 26a is closed, the refrigerant does not circulate, and the refrigerant discharged from the compressor 21 is sent into the outdoor heat exchanger 22 from the refrigerant flow passage 20c. Thus, the inside of the outdoor heat exchanger 22 becomes a high temperature and a high pressure. Thereby, the frost adhering to the outdoor heat exchanger 22 is melted by the heat released from the outdoor heat exchanger 22.

  Here, the time for closing the first electromagnetic valve 26a is such that at least the refrigerant in the accumulator 29 flows out and the pressure on the refrigerant suction side of the compressor 21 in order to prevent the occurrence of malfunctions such as failure of the compressor 21. Set the time when does not become negative pressure.

  In the reverse cycle defrosting operation, as shown in the timing chart of FIG. 8, the indoor fan 12, the compressor 21, the first control valve 24, the first electromagnetic valve 26 a, 3 is performed by switching the operation of the solenoid valve 26c.

  Specifically, first, the operation of the compressor 21 is stopped, the refrigerant flow path of the first control valve 24 is closed, and the indoor blower 12 is stopped. Next, the refrigerant flow path of the first control valve 24 is fixed at a predetermined opening on the condensation pressure adjusting means side, the first electromagnetic valve 26a is closed, and the third electromagnetic valve 26c is opened. In addition, after the operation of the first control valve 24, the first electromagnetic valve 26a and the third electromagnetic valve 26c, the compressor 21 is fixed at a predetermined rotational speed (for example, 4000 rpm) after a predetermined time has elapsed (for example, after 5 seconds). And drive. After starting the compressor 21 at a predetermined rotation speed, the compressor 21 is stopped after a predetermined time has elapsed (for example, after 45 seconds). After the compressor 21 is stopped, the fixed state of the refrigerant flow path of the first control valve 24, the closed state of the first electromagnetic valve 26a, and the open state of the third electromagnetic valve 26c are released, and the operation of the indoor blower 12 is started. Then, the reverse cycle defrosting operation is completed.

  In the reverse cycle defrosting operation, the refrigerant discharged from the compressor 21 flows and is sucked into the compressor 21 in the same manner as in the cooling operation and the dehumidifying cooling operation of FIG. The refrigerant flowing through the refrigerant circuit 20 dissipates heat in the outdoor heat exchanger 22 and absorbs heat in the heat absorber 14. Thereby, the refrigerant adhering to the outdoor heat exchanger 22 is melted by the heat that flows into the outdoor heat exchanger 22 and is released from the outdoor heat exchanger 22. Further, in the reverse cycle defrosting operation, the refrigerant flows into the outdoor heat exchanger 22 from the refrigerant flow passage 20d on the opposite side to the hot gas defrosting operation, so that the outdoor heat exchange in which frost is likely to remain by the hot gas defrosting operation. It is possible to positively melt the frost on the refrigerant flow passage 20d side of the vessel 22.

  Here, during the operation of switching the refrigerant flow path of the first control valve 24, the operation of the compressor 21 is stopped. In the reverse cycle defrosting operation, a time during which all the frost attached to the outdoor heat exchanger 22 can be melted is set as the operation time.

  The controller 30 determines whether or not the outdoor heat exchanger 22 is in an environmental condition that causes frost formation. If the controller 30 determines that the frost formation is in an environmental condition, the controller 30 performs the hot gas defrosting operation and the reverse cycle defrosting operation. A defrosting operation control process for performing the defrosting operation by any one is performed. The operation of the controller 30 at this time will be described with reference to the flowchart of FIG.

(Step S1)
In step S <b> 1, the CPU determines whether or not it is an environmental condition in which frost formation occurs in the outdoor heat exchanger 22. When it is determined that the environmental conditions cause frost formation, the process proceeds to step S2, and when it is not determined that the environmental conditions cause frost formation, the defrosting operation control process ends.
Whether or not frost formation occurs in the outdoor heat exchanger 22 is determined by detecting the temperature condition of the air outside the passenger compartment.

(Step S2)
If it is determined in step S1 that the outdoor heat exchanger 22 is in an environmental condition that causes frost formation, in step S2, the CPU determines whether or not a predetermined time (for example, 5 minutes) has elapsed since the previous defrosting operation. To do. If it is determined that the predetermined time has elapsed, the process proceeds to step S3. If it is not determined that the predetermined time has elapsed, the defrosting operation control process is terminated.

(Step S3)
When it is determined in step S2 that a predetermined time has elapsed since the previous defrosting operation, in step S3, the CPU determines whether or not the hot gas defrosting operation has been performed four times before the previous defrosting operation. If it is determined that the process is performed four times continuously, the process proceeds to step S4. If it is not determined that the process is performed four times continuously, the process proceeds to step S5.

(Step S4)
When it is determined in step S3 that the hot gas defrosting operation has been performed four times in succession, in step S4, the CPU executes the reverse cycle defrosting operation and ends the defrosting operation control process.
In the reverse cycle defrosting operation, the hot gas defrosting operation is set to be finished before the pressure on the refrigerant suction side of the compressor 21 becomes negative, but attached to the outdoor heat exchanger 22. It is possible to completely thaw the frost.

(Step S5)
When it is not determined in step S4 that the hot gas defrosting operation has been performed four times continuously, in step S5, the CPU executes the hot gas defrosting operation and ends the defrosting operation control process.
In the hot gas defrosting operation, the operation time of the reverse cycle defrosting operation is required for a long time including the switching of the flow path of the first control valve 24, whereas the frost adhering to the outdoor heat exchanger 22 is shortened. It is possible to melt efficiently in time.

  As described above, according to the vehicle air conditioner of the present embodiment, the refrigerant flow of the first control valve 24 can be determined when it is determined that the environmental condition in which frost formation of the outdoor heat exchanger 22 occurs during the heating operation. The hot gas defrosting operation is performed to close the first electromagnetic valve 26a after the passage is set to the maximum opening on the expansion means side and the refrigerant flow path of the first control valve 24 is set to the maximum opening on the expansion means side. Thereby, since the amount of heat radiation in the outdoor heat exchanger 22 can be increased with the inside of the outdoor heat exchanger 22 in a high-temperature and high-pressure state, frost attached to the outdoor heat exchanger 22 can be reliably removed. .

  Further, when the opening degree of the first control valve 24 and the opening and closing of the first electromagnetic valve 26a are switched in the hot gas defrosting means, the rotation speed of the compressor 21 is set to a predetermined rotation speed or higher. Thereby, when the refrigerant flow path of the first control valve 24 is set to the maximum opening on the expansion means side, the liquid refrigerant can be efficiently stored in the accumulator 29, and stored in the accumulator 29 when the first electromagnetic valve 26a is closed. Thus, it is possible to reliably flow the refrigerant into the outdoor heat exchanger 22.

  In the hot gas defrosting operation, the operation of the indoor blower 12 is stopped when switching the opening degree of the first control valve 24 and switching the opening and closing of the first electromagnetic valve 26a. Thereby, since the heat radiation of the refrigerant in the radiator 15 during the hot gas defrosting operation can be regulated, it is possible to allow the high-temperature refrigerant to flow into the outdoor heat exchanger 22.

  In addition, it is determined that the environmental condition is that frost formation occurs in the outdoor heat exchanger 22 during the heating operation, and in the case where the past defrosting operation up to the previous time is the hot gas defrosting operation four times in succession, The cycle defrosting operation is performed. Thereby, even when the frost adhering to the outdoor heat exchanger 22 is not completely melted by the hot gas defrosting operation, the frost adhering to the outdoor heat exchanger 22 is completely melted by the reverse cycle defrosting operation. It becomes possible.

  10 and 11 show a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected and shown to the component similar to the said embodiment.

  As shown in FIG. 10, the refrigerant circuit 20 of the vehicle air conditioner is provided with one refrigerant inlet and one refrigerant outlet in place of the first control valve 24 in the first embodiment. And a third control valve 32 capable of adjusting the valve opening in the respective ranges of the condensation pressure adjustment region.

  Specifically, the refrigerant flow path 20 a is provided by connecting the refrigerant inflow side of the radiator 15 to the refrigerant discharge side of the compressor 21. Further, a refrigerant flow passage 20 b is provided on the refrigerant outflow side of the radiator 15 by connecting the refrigerant inflow side of the third control valve 34. A refrigerant flow passage 20 c is provided on the refrigerant outflow side of the third control valve 34 by connecting the refrigerant inflow side of the outdoor heat exchanger 22. In addition, a refrigerant flow passage 20d is provided on the refrigerant outflow side of the outdoor heat exchanger 22 by connecting the refrigerant intake side of the compressor 21. The refrigerant flow passage 20d is provided with a first electromagnetic valve 26a and an accumulator 29 in order from the upstream side in the refrigerant flow direction. The refrigerant flow passage 20b is provided with a refrigerant flow passage 20e by connecting the high-pressure refrigerant inflow side of the internal heat exchanger 23 to the refrigerant flow passage 20b. In the refrigerant flow passage 20e, a second electromagnetic valve 26b and a first check valve 27a are provided in order from the upstream side in the refrigerant flow direction. A refrigerant flow passage 20 f is provided on the high-pressure refrigerant outflow side of the internal heat exchanger 23 by connecting the refrigerant inflow side of the heat absorber 14. An expansion valve 28 is provided in the refrigerant flow passage 20f. A refrigerant flow passage 20 g is provided on the refrigerant outflow side of the heat absorber 14 by connecting the low-pressure refrigerant inflow side of the internal heat exchanger 23. A second control valve 25 is provided in the refrigerant flow passage 20g. A refrigerant flow passage 20h is provided on the low-pressure refrigerant outflow side of the internal heat exchanger 23 by connecting the first electromagnetic valve 26a and the accumulator 29 of the refrigerant flow passage 20d. A refrigerant flow path 20i is provided on the refrigerant outflow side of the outdoor heat exchanger 22 by connecting the refrigerant inflow side of the gas-liquid separator 22a in parallel with the refrigerant flow path 20d. A third electromagnetic valve 26c is provided in the refrigerant flow passage 20i. A refrigerant flow passage 20j is provided on the refrigerant outflow side of the gas-liquid separation unit 22a by connecting the downstream side in the refrigerant flow direction of the first check valve 27a of the refrigerant flow passage 20e via the supercooling unit 22b. Yes. A second check valve 27b is provided in the refrigerant flow passage 20j.

In the heating operation of the vehicle air conditioner configured as described above, in the refrigerant circuit 20, the refrigerant flow path of the third control valve 32 is set on the expansion means side, the first electromagnetic valve 26a is opened, and the first The second to third electromagnetic valves 26b and 26c are closed, and the compressor 21 is operated.
Thus, as shown in FIG. 10, the refrigerant discharged from the compressor 21 flows in the order of the refrigerant flow passage 20a, the radiator 15, the refrigerant flow passages 20b and 20c, the outdoor heat exchanger 22, and the refrigerant flow passage 20d. And sucked into the compressor 21. The refrigerant flowing through the refrigerant circuit 20 dissipates heat in the radiator 15 and absorbs heat in the outdoor heat exchanger 22.

  In the defrosting operation, the refrigerant discharged from the compressor 21 is allowed to flow into the outdoor heat exchanger 22 without being reduced in pressure on the expansion means side of the third control valve 32, thereby melting the frost attached to the outdoor heat exchanger 22. This is performed by one of two methods: a hot gas defrosting operation and a reverse cycle defrosting operation in which the frost adhering to the outdoor heat exchanger 22 is melted by switching the refrigerant circuit 20 to the cooling operation.

  The hot gas defrosting operation switches the operation of the indoor blower 12, the compressor 21, the third control valve 32, and the first electromagnetic valve 26a in the state where the heating operation is performed, as in the first embodiment. Is done by.

  Specifically, first, the rotational speed of the compressor 21 is fixed to a predetermined rotational speed (for example, 4000 rpm), the refrigerant flow path of the third control valve 32 is fixed to the maximum opening on the expansion means side, and the indoor fan 12 is stopped. Next, the first electromagnetic valve 26a is closed after a predetermined time has elapsed (for example, 20 seconds later) after the refrigerant flow path of the third control valve 32 is fixed to the maximum opening on the expansion means side. Finally, after a predetermined time has elapsed since the first electromagnetic valve 26a was closed (for example, after 10 seconds), the first electromagnetic valve 26a is opened, the rotational speed of the compressor 21 is fixed, and the indoor fan 12 The hot gas defrosting operation is terminated by releasing the stopped state and the fixed state of the maximum opening degree of the refrigerant flow path of the third control valve 32 on the expansion means side.

  In the hot gas defrosting operation, the refrigerant discharged from the compressor 21 flows through the same flow path as in the heating operation of FIG. Since the refrigerant flowing through the refrigerant circuit 20 is not decompressed by the third control valve 32, it is liquefied by radiating heat in the outdoor heat exchanger 22, and the liquefied refrigerant is stored in the accumulator 29. Thereby, in the refrigerant circuit 20, since the flow volume of a refrigerant | coolant reduces, the pressure of the refrigerant | coolant in the outdoor heat exchanger 22 becomes low.

  When the first electromagnetic valve 26a is closed when the pressure of the refrigerant in the outdoor heat exchanger 22 is low and the liquid refrigerant is stored in the accumulator 29, the refrigerant flow path between the compressor 21 and the first electromagnetic valve 26a. 20 e becomes a low pressure, and the liquid refrigerant stored in the accumulator 29 is vaporized and discharged from the compressor 21. At this time, in the refrigerant circuit 20, since the first electromagnetic valve 26a is closed, the refrigerant does not circulate, and the refrigerant discharged from the compressor 21 is sent into the outdoor heat exchanger 22 from the refrigerant flow passage 20c. Thus, the inside of the outdoor heat exchanger 22 becomes a high temperature and a high pressure. Thereby, the frost adhering to the outdoor heat exchanger 22 is melted by the heat released from the outdoor heat exchanger 22.

  Here, the time for closing the first electromagnetic valve 26a is such that at least the refrigerant in the accumulator 29 flows out and the pressure on the refrigerant suction side of the compressor 21 in order to prevent the occurrence of malfunctions such as failure of the compressor 21. Set the time when does not become negative pressure.

  Further, in the reverse cycle defrosting operation, the indoor fan 12, the compressor 21, the third control valve 32, the first electromagnetic valve 26a, and the third electromagnetic wave in the state where the heating operation is performed, as in the first embodiment. This is done by switching the operation of the valve 26c.

  Specifically, first, the operation of the compressor 21 is stopped, the refrigerant flow path of the third control valve 32 is closed, and the indoor blower 12 is stopped. Next, the refrigerant flow path of the third control valve 32 is fixed at a predetermined opening on the condensation pressure adjusting means side, and the first electromagnetic valve 26a is closed and the third electromagnetic valve 26c is opened. In addition, after the operation of the third control valve 32, the first electromagnetic valve 26a and the third electromagnetic valve 26c, the compressor 21 is fixed at a predetermined rotational speed (for example, 4000 rpm) after a predetermined time has elapsed (for example, after 5 seconds). And drive. After starting the compressor 21 at a predetermined rotation speed, the compressor 21 is stopped after a predetermined time has elapsed (for example, after 45 seconds). After the compressor 21 is stopped, the fixed state of the refrigerant flow path of the third control valve 32, the closed state of the first electromagnetic valve 26a, and the open state of the third electromagnetic valve 26c are released, and the operation of the indoor blower 12 is started. Then, the reverse cycle defrosting operation is completed.

  In the reverse cycle defrosting operation, the refrigerant discharged from the compressor 21 flows and is sucked into the compressor 21 as in the cooling operation and the dehumidifying cooling operation, as shown in FIG. The refrigerant flowing through the refrigerant circuit 20 dissipates heat in the outdoor heat exchanger 22 and absorbs heat in the heat absorber 14. Thereby, the refrigerant adhering to the outdoor heat exchanger 22 is melted by the heat that flows into the outdoor heat exchanger 22 and is released from the outdoor heat exchanger 22.

  Here, during the operation of switching the refrigerant flow path of the third control valve 32, the operation of the compressor 21 is stopped. In the reverse cycle defrosting operation, a time during which all the frost attached to the outdoor heat exchanger 22 can be melted is set as the operation time.

  As described above, according to the vehicle air conditioner of this embodiment, the amount of heat released from the outdoor heat exchanger 22 can be increased by setting the temperature of the outdoor heat exchanger 22 to a high temperature and high pressure state, as in the above embodiment. Therefore, it is possible to reliably remove frost attached to the outdoor heat exchanger 22.

  In the above embodiment, the case where the temperature of the air outside the passenger compartment is equal to or lower than the predetermined temperature is shown as an example of the environmental condition in which frost formation occurs in the outdoor heat exchanger 22, but the present invention is not limited to this. As another example, it may be determined that frost formation occurs by detecting a case where the temperature outside the vehicle compartment is equal to or lower than the predetermined temperature and the humidity outside the vehicle compartment is equal to or higher than the predetermined humidity. Alternatively, it may be determined that frost formation occurs by detecting a case where the temperature outside the passenger compartment is equal to or lower than the predetermined temperature and the evaporation temperature of the refrigerant in the outdoor heat exchanger 22 is equal to or lower than the predetermined temperature.

  Moreover, in the said embodiment, what showed fixing the rotation speed of the compressor 21 to the predetermined rotation speed in the case of hot gas defrost operation was shown, However, It is not restricted to this. For example, if the operation of the compressor 21 is not stopped, the hot gas defrosting operation can be performed even if the rotation speed of the compressor 21 is changed.

  Moreover, in the said embodiment, the expansion means for decompressing the refrigerant | coolant which flows in into the outdoor heat exchanger 22 at the time of heating operation and 1st dehumidification heating operation, and for condensing pressure of the refrigerant | coolant in the radiator 15 at the time of dehumidification cooling operation are controlled. Although the 1st control valve 24 which has a condensation pressure adjustment means was shown, it is not restricted to this. For example, instead of the first control valve 24, the refrigerant circuit 20 may be configured separately with an expansion means having a variable opening and a condensation pressure adjustment means.

  Moreover, although the said embodiment showed what stopped the indoor air blower 12 in the case of hot gas defrost operation, it is not restricted to this. When the indoor blower 12 is operated during the hot gas defrosting operation, the refrigerant discharged from the compressor 21 dissipates heat in the radiator 15, so that warm air can be supplied into the vehicle interior.

  Further, in the above embodiment, during the hot gas defrosting operation, as the time for closing the first electromagnetic valve 26a, the refrigerant in the accumulator 29 flows out and the pressure on the refrigerant suction side of the compressor 21 does not become negative. Although the time is set, the present invention is not limited to this. If the pressure on the refrigerant suction side of the compressor 21 can be allowed to be negative, for example, the pressure on the suction side of the compressor 21 is detected while the first electromagnetic valve 26a is closed in the hot gas defrosting operation. The first electromagnetic valve 26a may be opened when the detected pressure is equal to or lower than a predetermined pressure.

  Moreover, in the said embodiment, when the past defrosting operation was a hot gas defrosting operation continuously 4 times, what showed reverse cycle defrosting operation was shown, However, It is not restricted to this. . For example, the reverse cycle defrosting operation may be performed when the past defrosting operation is the hot gas defrosting operation continuously three times or less or five times or more. Moreover, you may make it perform reverse cycle defrost operation on environmental conditions different from hot gas defrost operation.

  In the above embodiment, in the hot gas defrosting operation, the indoor blower 12 is stopped when switching the opening and closing of the first solenoid valve 26a and the fourth solenoid valve 26d. It is not something that can be done. You may make it make the ventilation volume of the indoor blower 12 lower than the ventilation volume at the time of heating operation, without stopping the indoor blower 12. FIG.

  Moreover, in the said embodiment, as shown in the timing chart in the hot gas defrosting operation and the reverse cycle defrosting operation, the one in which the rotation speed of the compressor 21 is abruptly changed is shown. Instead, the rotational speed of the compressor 21 may be gradually changed.

  DESCRIPTION OF SYMBOLS 10 ... Air conditioning unit, 14 ... Heat absorber, 15 ... Radiator, 20 ... Refrigerant circuit, 21 ... Compressor, 22 ... Outdoor heat exchanger, 24 ... 1st control valve, 26a, 26b, 26c ... 1st-3rd Solenoid valve, 29 ... accumulator, 32 ... third control valve.

Claims (4)

A compressor that compresses and discharges the refrigerant;
A radiator that dissipates the refrigerant,
A heat absorber that absorbs the refrigerant;
An outdoor heat exchanger that radiates or absorbs refrigerant,
The refrigerant discharged from the compressor flows into the radiator to dissipate heat, and at least a part of the refrigerant that has circulated through the radiator flows into the outdoor heat exchanger via the expansion valve to absorb heat, and circulates through the outdoor heat exchanger. A heating refrigerant circuit for causing the refrigerant to flow into the accumulator and for the refrigerant flowing out of the accumulator to be sucked into the compressor;
A valve opening adjustment mechanism for adjusting the valve opening of the expansion valve;
An on-off valve that opens and closes a refrigerant flow path between the refrigerant outflow side of the outdoor heat exchanger and the refrigerant inflow side of the accumulator;
Frost determination means for determining whether or not a condition for causing frost formation in the outdoor heat exchanger is satisfied;
During the heating operation, when it is determined by the frost determination means that the frost formation of the outdoor heat exchanger occurs, the valve opening degree of the expansion valve is opened by the valve opening adjustment mechanism during the heating operation. And a hot gas defrosting means for closing the on-off valve after increasing the valve opening degree of the expansion valve. The compressor control means for setting the rotational speed of the compressor to a predetermined rotational speed or higher when switching the opening degree of the expansion valve and switching the open / close valve by the hot gas defrosting means is provided. The vehicle air conditioner according to claim 1. A blower for circulating air to exchange heat with the refrigerant in one or both of the radiator and the heat absorber;
When switching the opening of the expansion valve and switching the opening and closing of the on-off valve by the hot gas defrosting means, the air flow rate of the blower is made lower than the air flow rate of the blower during operation in which the refrigerant flows through the heating refrigerant circuit The air conditioner for vehicles according to claim 1 or 2, comprising a blower control means. The refrigerant discharged from the compressor flows into the outdoor heat exchanger to dissipate the heat, and the refrigerant flowing through the outdoor heat exchanger flows into the heat absorber through the expansion means to absorb heat, and the refrigerant flowing through the heat absorber is compressed into the compressor. A reverse cycle circuit to inhale,
During the heating operation, the reverse cycle defrosting is performed such that the frost determination unit determines that the outdoor heat exchanger is frosted and the refrigerant is passed through the reverse cycle circuit when a predetermined condition is satisfied. The vehicle air conditioner according to any one of claims 1 to 3, further comprising: means.

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