JP2018077004A - Refrigeration cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a backflow of an air-phase refrigerant which is separated in an air-liquid separator in a compressor through a differential pressure valve when stopping the compressor.SOLUTION: A refrigeration cycle device comprises: an air-liquid separation part 14 for separating an air-liquid of a refrigerant which is decompressed by a high-stage side decompression part; low-stage side decompression parts 17, 18 and 18a for decompressing a liquid-phase refrigerant which is separated by the air-liquid separation part; an evaporator 20 for evaporating the refrigerant which is decompressed by the low-stage side decompression parts; an air-phase refrigerant passage 15 in which an air-phase refrigerant which is separated by the air-liquid separation part flows; and a differential pressure valve 16 for opening and closing the air-phase refrigerant passage by differential pressure between the refrigerant which is decompressed by the low-stage side decompression parts and the refrigerant which flows in the air-phase refrigerant passage. The low-stage side decompression parts have adjustment mechanisms 18, 18a for adjusting a decompression amount of the refrigerant, and also comprises a control device 40 for performing compressor stop delay control for stopping the compressor after the low-stage side decompression parts are controlled so that the decompression amount of the refrigerant is reduced when it is decided to stop the compressor.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a refrigeration cycle apparatus including a two-stage compression compressor.

  Conventionally, Patent Document 1 describes a refrigeration cycle apparatus including a compressor, an indoor condenser, a gas-liquid separator, a high stage side expansion valve, a fixed throttle, an outdoor heat exchanger, a differential pressure valve, and the like.

  In the heating mode, the high-pressure refrigerant discharged from the discharge port of the compressor flows into the indoor condenser. The refrigerant flowing into the indoor condenser radiates heat by exchanging heat with the air blown into the passenger compartment. Thereby, the air blown into the passenger compartment is heated.

  The refrigerant flowing out of the indoor condenser is decompressed and expanded in an enthalpy manner until it becomes an intermediate pressure refrigerant by the high-stage expansion valve that is in a throttled state. The intermediate-pressure refrigerant decompressed by the high stage side expansion valve flows into the gas-liquid separation unit and is gas-liquid separated.

  The liquid phase refrigerant separated in the gas-liquid separation unit is decompressed and expanded in an isoenthalpy manner until it becomes a low-pressure refrigerant in a fixed throttle. The refrigerant decompressed and expanded by the fixed throttle flows into the outdoor heat exchanger and exchanges heat with the outside air to absorb heat. The refrigerant flowing out of the outdoor heat exchanger is sucked from the suction port of the compressor and compressed again.

  In the heating mode, the pressure of the low-pressure refrigerant decompressed by the fixed throttle is guided to the differential pressure valve, so that the differential pressure valve opens. Thereby, the gaseous-phase refrigerant | coolant isolate | separated in the gas-liquid separation part flows in into the intermediate pressure port side of a compressor. The intermediate-pressure gas-phase refrigerant that has flowed into the intermediate-pressure port joins with the refrigerant sucked from the suction port of the compressor and compressed by the low-stage compression mechanism, and is compressed by the high-stage compression mechanism.

  As described above, in the heating mode, the heat of the refrigerant discharged from the compressor in the indoor condenser can be dissipated to the air blown into the vehicle interior, and the heated air can be blown out into the vehicle interior. Thereby, heating of a vehicle interior is realizable.

  Further, in the heating mode, the low-pressure refrigerant decompressed by the fixed throttle is sucked from the suction port of the compressor, and the intermediate-pressure refrigerant decompressed by the high stage side expansion valve is introduced into the intermediate pressure port of the compressor to increase the pressure. A gas injection cycle (in other words, an economizer refrigeration cycle) that merges with the refrigerant in the process can be configured.

  Accordingly, the refrigerant mixture having a low temperature can be sucked into the high-stage compression mechanism of the compressor, the compression efficiency of the high-stage compression mechanism can be improved, and the low-stage compression mechanism and the high-stage side can be improved. By reducing the pressure difference between the suction refrigerant pressure and the discharge refrigerant pressure of both compression mechanisms, the compression efficiency of both compression mechanisms can be improved. As a result, the coefficient of performance (so-called COP) of the entire refrigeration cycle can be improved during the heating mode in which the difference between the high and low pressures of the cycle becomes large.

JP 2013-92355 A

  In the above prior art, when the compressor is stopped in the heating mode, the gas-phase refrigerant separated by the gas-liquid separator flows into the compressor from the intermediate pressure port through the differential pressure valve, and compared with the intermediate pressure port side. It will flow backward to the suction port side where the pressure is low. As a result, there has been a problem that abnormal noise is generated due to reverse rotation of the compressor scroll and irregular collision with the wall surface of the compression chamber.

  In view of the above points, an object of the present invention is to prevent the gas-phase refrigerant separated by the gas-liquid separator from flowing backward through the differential pressure valve when the compressor is stopped.

In order to achieve the above object, in the refrigeration cycle apparatus according to claim 1,
A compressor (11) that sucks and compresses refrigerant from the suction port (11a) and discharges it from the discharge port (11c);
A high-pressure side heat exchanger (12) for exchanging heat of the refrigerant discharged from the discharge port;
A high-stage decompression section (13) that decompresses the refrigerant flowing out of the high-pressure side heat exchanger;
A gas-liquid separation unit (14) for separating the gas-liquid of the refrigerant decompressed by the high-stage decompression unit;
A lower-stage decompression section (17, 18, 18a) for decompressing the liquid-phase refrigerant separated in the gas-liquid separation section;
An evaporator (20) for evaporating the refrigerant decompressed in the low-stage decompression unit;
A gas-phase refrigerant passage (15) through which the gas-phase refrigerant separated in the gas-liquid separator flows,
A differential pressure valve (16) that opens and closes the gas-phase refrigerant passage by a pressure difference between the refrigerant decompressed by the low-stage decompression section and the refrigerant flowing through the gas-phase refrigerant passage,
The compressor has an intermediate pressure port (11b) through which the refrigerant flowing through the gas-phase refrigerant passage flows, and the refrigerant flowing in from the intermediate pressure port joins the refrigerant in the compression process sucked from the suction port. And
The low-stage decompression unit has an adjustment mechanism (18, 18a) for adjusting the decompression amount of the refrigerant,
Furthermore, when it is determined to stop the compressor, a control unit (40) that performs compressor stop delay control for stopping the compressor after controlling the low-stage decompression unit so that the amount of decompression of the refrigerant decreases. Prepare.

  According to this, since the pressure of the low-pressure refrigerant on the suction port (11a) side increases due to a decrease in the amount of refrigerant decompression in the low-stage decompression section (17, 18, 18a), the intermediate pressure port (11b) The pressure difference from the suction port (11a) is reduced.

  Therefore, when the compressor (11) is stopped, the gas-phase refrigerant separated by the gas-liquid separator (14) is prevented from flowing to the low pressure side of the compressor (11) through the differential pressure valve (16). it can. As a result, it can suppress that a compressor (11) reversely rotates and a vibration and abnormal noise generate | occur | produce.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a whole block diagram which shows the refrigerant circuit at the time of the air_conditioning | cooling mode of the heat pump cycle in one Embodiment, and a serial dehumidification heating mode. It is a whole block diagram which shows the refrigerant circuit at the time of the parallel dehumidification heating mode of the heat pump cycle in one Embodiment. It is a whole lineblock diagram showing the refrigerant circuit at the time of the heating mode of the heat pump cycle in one embodiment. It is a time chart which shows the operation example of the compressor stop delay control of the heat pump cycle in one Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. In the present embodiment, the heat pump cycle 10 is applied to the vehicle air conditioner 1 of a hybrid vehicle that obtains a driving force for traveling from an engine (in other words, an internal combustion engine) and a traveling electric motor. The heat pump cycle 10 is a vapor compression refrigeration cycle.

  The heat pump cycle 10 fulfills the function of cooling or heating the air blown into the vehicle interior that is the air-conditioning target space in the vehicle air conditioner 1. Therefore, the air-conditioning target space of this embodiment is a vehicle interior, and the heat exchange target fluid of this embodiment is air blown into the vehicle interior.

  The heat pump cycle 10 is configured to be able to switch between the cooling mode shown in FIG. 1, the serial dehumidification heating mode shown in FIG. 1, the parallel dehumidification heating mode shown in FIG. 2, or the heating mode shown in FIG. 3. 1-3, the flow of the refrigerant | coolant in each operation mode is shown by the solid line arrow.

  The cooling mode is a cooling operation mode in which the air blown into the passenger compartment is cooled to cool the passenger compartment. The series dehumidification heating mode and the parallel dehumidification heating mode are dehumidification heating operation modes in which the air blown into the vehicle interior is dehumidified and then heated to dehumidify and heat the vehicle interior. The heating mode is a heating operation mode in which air blown into the passenger compartment is heated to heat the passenger compartment.

  The heat pump cycle 10 employs an HFC-based refrigerant (specifically, R134a) as a refrigerant, and constitutes a vapor compression subcritical refrigeration cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant. An HFO refrigerant (for example, R1234yf) or the like may be employed as the refrigerant. Refrigerating machine oil for lubricating the compressor 11 is mixed in the refrigerant, and a part of the refrigerating machine oil circulates in the cycle together with the refrigerant.

  The compressor 11 of the heat pump cycle 10 sucks the refrigerant, compresses it, and discharges it. The compressor 11 is arrange | positioned in the hood of a vehicle. The compressor 11 houses two compression mechanisms, a low-stage compression mechanism and a high-stage compression mechanism, and an electric motor that rotationally drives both compression mechanisms in a housing that forms the outer shell. This is a two-stage booster type electric compressor configured.

  The housing of the compressor 11 has a suction port 11a for sucking low-pressure refrigerant from the outside of the housing into the low-stage compression mechanism, and an intermediate-pressure refrigerant flows from the outside of the housing to the inside of the housing to compress from low pressure to high pressure. An intermediate pressure port 11b for joining the refrigerant and a discharge port 11c for discharging the high-pressure refrigerant discharged from the high-stage compression mechanism to the outside of the housing are provided.

  The intermediate pressure port 11b is connected to the refrigerant discharge port side of the low-stage compression mechanism (that is, the refrigerant suction port side of the high-stage compression mechanism). Various types such as a scroll-type compression mechanism, a vane-type compression mechanism, and a rolling piston-type compression mechanism can be adopted as the low-stage side compression mechanism and the high-stage side compression mechanism.

  The rotation speed of the electric motor of the compressor 11 is controlled by a control signal output from the control device 40. As the electric motor, either an AC motor or a DC motor may be adopted. The refrigerant discharge capacity of the compressor 11 is changed by controlling the rotational speed of the electric motor. Therefore, the electric motor is a discharge capacity changing unit of the compressor 11.

  In this embodiment, although the compressor 11 which accommodated two compression mechanisms in one housing is employ | adopted, the format of a compressor is not limited to this. That is, if the intermediate pressure refrigerant can be introduced from the intermediate pressure port 11b and merged with the refrigerant in the compression process from low pressure to high pressure, one fixed capacity type compression mechanism and the compression mechanism are provided inside the housing. An electric compressor configured to accommodate an electric motor that rotationally drives the motor may be used.

  Two compressors are connected in series, and the suction port of the low-stage compression mechanism disposed on the low-stage side is defined as the suction port 11a, and the discharge port of the high-stage compression mechanism disposed on the high-stage side is the discharge port. 11c, an intermediate pressure port 11b is provided at a connection portion that connects the discharge port of the low-stage compression mechanism and the suction port of the high-stage compression mechanism, and is provided by both the low-stage compression mechanism and the high-stage compression mechanism. One two-stage booster compressor may be configured.

  The refrigerant inlet side of the indoor condenser 12 is connected to the discharge port 11 c of the compressor 11. The indoor condenser 12 is disposed in the air conditioning case 31 of the indoor air conditioning unit 30 of the vehicle air conditioner 1 and dissipates heat from the high-temperature and high-pressure refrigerant discharged from the high-stage compression mechanism of the compressor 11 (in other words, , An air heating heat exchanger that functions as a high pressure side heat exchanger and heats the air that has passed through the indoor evaporator 23.

  The inlet side of the high stage side expansion valve 13 is connected to the refrigerant outlet side of the indoor condenser 12. The high-stage expansion valve 13 is a high-stage decompression unit that decompresses the high-pressure refrigerant flowing out of the indoor condenser 12 until it becomes an intermediate-pressure refrigerant. The high stage side expansion valve 13 is a first pressure reducing unit.

  The high-stage side expansion valve 13 is an electrically variable type that includes a valve body that can change the throttle opening degree and an electric actuator that includes a stepping motor that changes the throttle opening degree of the valve body. An aperture mechanism.

  The high stage side expansion valve 13 may be configured so that the throttle opening is fully opened and the refrigerant decompression action is not exhibited. The operation of the high stage side expansion valve 13 is controlled by a control signal output from the control device 40.

  A refrigerant inflow port 14 a of the gas-liquid separator 14 is connected to the outlet side of the high stage side expansion valve 13. The gas-liquid separator 14 is a gas-liquid separation unit that separates the gas-liquid of the intermediate pressure refrigerant that has flowed out of the indoor condenser 12 and decompressed by the high-stage expansion valve 13. The gas-liquid separator 14 is of a centrifugal separation type that separates the gas-liquid refrigerant by the action of centrifugal force.

  An intermediate pressure port 11 b of the compressor 11 is connected to the gas-phase refrigerant outlet port 14 b of the gas-liquid separator 14 via an intermediate pressure refrigerant passage 15. A gas-phase refrigerant side on-off valve 16 is disposed in the intermediate pressure refrigerant passage 15. The intermediate pressure refrigerant passage 15 is a gas phase refrigerant passage through which the gas phase refrigerant flowing out from the gas phase refrigerant outlet port 14b of the gas-liquid separator 14 flows.

  The gas-phase refrigerant side opening / closing valve 16 is a differential pressure valve that is displaced by a pressure difference between the refrigerant pressure in the pressure introduction passage 19 and the refrigerant pressure in the intermediate pressure refrigerant passage 15. The refrigerant pressure on the inlet side of the outdoor heat exchanger 20 is guided to the gas-phase refrigerant side on-off valve 16 through the pressure introduction passage 19.

  Specifically, when the refrigerant is depressurized by the fixed throttle 17, the pressure difference between the refrigerant pressure in the pressure introduction passage 19 and the refrigerant pressure in the intermediate pressure refrigerant passage 15 becomes large. The pressure refrigerant passage 15 is opened.

  When the liquid refrigerant side opening / closing valve 18a opens the fixed throttle bypass passage 18 and the refrigerant bypasses the fixed throttle 17 and is guided to the outdoor heat exchanger 20 side and the refrigerant is not decompressed by the fixed throttle 17, the pressure introduction passage 19 Since the pressure difference between the refrigerant pressure and the refrigerant pressure in the intermediate pressure refrigerant passage 15 becomes small, the gas phase refrigerant side on-off valve 16 closes the intermediate pressure refrigerant passage 15.

  The gas-phase refrigerant side on-off valve 16 functions to switch the refrigerant flow path of the heat pump cycle 10 by opening and closing the intermediate pressure refrigerant passage 15. Accordingly, the gas-phase refrigerant side on-off valve 16 constitutes a refrigerant flow path switching unit that switches the refrigerant flow path of the refrigerant circulating in the cycle.

  On the other hand, the liquid refrigerant outlet port 14 c of the gas-liquid separator 14 is connected to the inlet side of the fixed throttle 17, and the outlet side of the fixed throttle 17 is connected to the refrigerant inlet side of the outdoor heat exchanger 20. The fixed throttle 17 is a low-stage decompression unit that decompresses the liquid-phase refrigerant separated by the gas-liquid separator 14 until it becomes a low-pressure refrigerant. As the fixed throttle 17, a nozzle or an orifice having a fixed throttle opening can be employed.

  In fixed throttles such as nozzles and orifices, the area of the throttle passage is suddenly reduced or expanded rapidly, so that the refrigerant passing through the fixed throttle is changed with the change in the pressure difference between the upstream side and the downstream side (that is, the differential pressure between the inlet and outlet). The flow rate and the dryness of the fixed throttle upstream refrigerant can be self-adjusted.

  Specifically, when the pressure difference is relatively large, a balance is made so that the dryness of the fixed throttle upstream side refrigerant increases as the necessary circulating refrigerant flow rate required to circulate the cycle decreases. On the other hand, when the pressure difference is relatively small, it is balanced so that the dryness of the fixed throttle upstream side refrigerant decreases as the required circulating refrigerant flow rate increases.

  A fixed-throttle bypass passage 18 that guides the liquid-phase refrigerant separated by the gas-liquid separator 14 to the outdoor heat exchanger 20 side is bypassed at the liquid-phase refrigerant outlet port 14c of the gas-liquid separator 14. It is connected. A liquid-phase refrigerant side opening / closing valve 18 a is disposed in the fixed throttle bypass passage 18. The liquid-phase refrigerant side opening / closing valve 18 a is an electromagnetic valve that opens and closes the fixed throttle bypass passage 18, and its opening / closing operation is controlled by a control signal output from the control device 40.

  Further, the pressure loss that occurs when the refrigerant passes through the liquid-phase refrigerant-side on-off valve 18 a is extremely small compared to the pressure loss that occurs when the refrigerant passes through the fixed throttle 17. Accordingly, the refrigerant flowing out of the indoor condenser 12 flows into the outdoor heat exchanger 20 via the fixed throttle bypass passage 18 side when the liquid phase refrigerant side opening / closing valve 18a is open, and the liquid phase refrigerant side opening / closing valve. When 18 a is closed, it flows into the outdoor heat exchanger 20 through the fixed throttle 17.

  Thereby, the liquid phase refrigerant | coolant side on-off valve 18a can switch the refrigerant | coolant flow path of the heat pump cycle 10. FIG. Therefore, the liquid phase refrigerant side opening / closing valve 18a of the present embodiment, together with the gas phase refrigerant side opening / closing valve 16, constitutes a refrigerant channel switching unit that switches the refrigerant channel of the refrigerant circulating in the cycle.

  As such a refrigerant flow switching unit, a refrigerant circuit that connects the liquid phase refrigerant outflow port 14c outlet side of the gas-liquid separator 14 and the fixed throttle 17 inlet side, and the liquid phase refrigerant outflow port 14c outlet side and the fixed throttle bypass. An electric three-way valve or the like that switches the refrigerant circuit connecting the inlet side of the passage 18 may be adopted.

  The fixed throttle detour passage 18 and the liquid-phase refrigerant side opening / closing valve 18 a are adjustment mechanisms that adjust the amount of refrigerant reduced in the fixed throttle 17.

  The refrigerant inlet side of the outdoor heat exchanger 20 is connected to the outlet side of the fixed throttle 17 and the fixed throttle bypass passage 18. The outdoor heat exchanger 20 is disposed in the hood, and exchanges heat between the refrigerant circulating inside and the outside air blown from the blower fan 21. The outdoor heat exchanger 20 functions as an evaporator that evaporates low-pressure refrigerant and exerts an endothermic action at least in the heating mode, and functions as a radiator that radiates heat from the high-pressure refrigerant in the cooling mode and the like. It is.

  The refrigerant outlet side of the outdoor heat exchanger 20 is connected to the refrigerant inlet side of the cooling expansion valve 22 as a second pressure reducing unit. The cooling expansion valve 22 depressurizes the refrigerant that flows out of the outdoor heat exchanger 20 and flows into the indoor evaporator 23 in the cooling operation mode or the like. The basic configuration of the cooling expansion valve 22 is the same as that of the high-stage expansion valve 13, and its operation is controlled by a control signal output from the control device 40.

  The refrigerant inlet side of the indoor evaporator 23 is connected to the outlet side of the cooling expansion valve 22. The indoor evaporator 23 is disposed on the air flow upstream side of the indoor condenser 12 in the air conditioning case 31 of the indoor air conditioning unit 30, and evaporates the refrigerant that circulates in the cooling operation mode and the dehumidifying heating operation mode. The heat exchanger functions as an evaporator (in other words, an air cooling heat exchanger) that cools the air blown into the vehicle interior by exerting an endothermic action.

  The outlet side of the indoor evaporator 23 is connected to the inlet side of the accumulator 24. The accumulator 24 is a low-pressure side gas-liquid separator that separates the gas-liquid refrigerant flowing into the accumulator 24 and stores excess refrigerant. Furthermore, the suction port 11 a of the compressor 11 is connected to the gas phase refrigerant outlet of the accumulator 24. Therefore, the indoor evaporator 23 is connected so as to flow out to the suction port 11 a side of the compressor 11.

  Further, on the refrigerant outlet side of the outdoor heat exchanger 20, the low-pressure side bypass passage 25 that guides the refrigerant flowing out of the outdoor heat exchanger 20 to the inlet side of the accumulator 24 while bypassing the cooling expansion valve 22 and the indoor evaporator 23. Is connected. A low pressure side bypass passage opening / closing valve 26 is arranged in the low pressure side bypass passage 25.

  The low pressure side bypass passage opening / closing valve 26 is an electromagnetic valve that opens and closes the low pressure side bypass passage 25, and its opening / closing operation is controlled by a control voltage output from the control device 40. Further, the pressure loss that occurs when the refrigerant passes through the low pressure side bypass passage opening / closing valve 26 is extremely small compared to the pressure loss that occurs when the refrigerant passes through the cooling expansion valve 22.

  Accordingly, the refrigerant that has flowed out of the outdoor heat exchanger 20 flows into the accumulator 24 through the low pressure side bypass passage 25 when the low pressure side bypass passage opening / closing valve 26 is open. At this time, the throttle opening degree of the cooling expansion valve 22 may be fully closed.

  Further, when the low pressure side bypass passage opening / closing valve 26 is closed, it flows into the indoor evaporator 23 via the cooling expansion valve 22. Thereby, the low pressure side bypass passage opening / closing valve 26 can switch the refrigerant flow path of the heat pump cycle 10. Therefore, the low pressure side bypass passage opening / closing valve 26 of the present embodiment constitutes a refrigerant flow path switching unit that switches the refrigerant flow path of the refrigerant circulating in the cycle.

  A constant pressure valve 27 is disposed on the outlet side of the indoor evaporator 23 and on the inlet side of the accumulator 24. The constant pressure valve 27 is a constant pressure adjusting unit that maintains the refrigerant pressure at the outlet side of the indoor evaporator 23 at a predetermined pressure.

  The high-pressure side bypass passage 28 passes the refrigerant in the range from the outlet side of the indoor condenser 12 to the inlet side of the high-stage expansion valve 13 from the outlet side of the outdoor heat exchanger 20 to the inlet side of the cooling expansion valve 22. It is a refrigerant passage leading to the range. In other words, the high-pressure side bypass passage 28 is a refrigerant passage that guides the refrigerant flowing out of the indoor condenser 12 to the inlet side of the cooling expansion valve 22 by bypassing the high-stage side expansion valve 13 and the outdoor heat exchanger 20. .

  A high pressure side bypass passage opening / closing valve 28 a is disposed in the high pressure side bypass passage 28. The high pressure side bypass passage opening / closing valve 28 a is an electromagnetic valve that opens and closes the high pressure side bypass passage 28, and its operation is controlled by a control signal output from the control device 40.

  The high pressure side bypass passage opening / closing valve 28a functions to switch the cycle configuration (in other words, the refrigerant passage) by opening and closing the high pressure side bypass passage 28. Therefore, the high-pressure side bypass passage opening / closing valve 28a constitutes a refrigerant flow path switching unit that switches the refrigerant flow path of the refrigerant circulating in the cycle.

  A check valve 29 is disposed on the outlet side of the outdoor heat exchanger 20. The check valve 29 allows the refrigerant to flow from the outlet side of the outdoor heat exchanger 20 to the inlet side of the cooling expansion valve 22 and from the inlet side of the cooling expansion valve 22 to the outlet side of the outdoor heat exchanger 20. It is a backflow prevention part which prohibits the flow of the refrigerant | coolant. The check valve 29 can prevent the refrigerant flowing through the high-pressure side bypass passage 28 from flowing back to the outdoor heat exchanger 20 side.

  Next, the indoor air conditioning unit 30 will be described. The indoor air conditioning unit 30 is disposed inside the instrument panel at the foremost part of the vehicle interior, forms an outer shell of the indoor air conditioning unit 30, and forms an air passage for air blown into the vehicle interior in the interior. 31. And the air blower 32, the indoor condenser 12, the indoor evaporator 23, etc. are accommodated in this air passage.

  On the most upstream side of the air flow in the air conditioning case 31, an inside / outside air switching device 33 that switches between introduction of inside air and outside air is arranged. The inside / outside air switching device 33 continuously adjusts the opening area of the inside air introduction port for introducing the inside air into the air conditioning case 31 and the outside air introduction port for introducing the outside air by the inside / outside air switching door, so that the air volume of the inside air and the outside air are adjusted. The air volume ratio with the air volume is continuously changed.

  On the downstream side of the air flow of the inside / outside air switching device 33, a blower 32 that blows air sucked through the inside / outside air switching device 33 toward the vehicle interior is arranged. The blower 32 is an electric blower that drives a centrifugal multiblade fan by an electric motor, and the number of rotations (in other words, the amount of blown air) is controlled by a control voltage output from the control device 40.

  On the downstream side of the air flow of the blower 32, the indoor evaporator 23 and the indoor condenser 12 are arranged in the order of the indoor evaporator 23 → the indoor condenser 12 with respect to the flow of air blown into the vehicle interior. In other words, the indoor evaporator 23 is disposed on the upstream side of the air flow with respect to the indoor condenser 12.

  A heater core (not shown) is disposed between the indoor evaporator 23 and the indoor condenser 12. The heater core is an auxiliary heating heat exchanger that auxiliary heats the air by exchanging heat between the engine coolant and the air that has passed through the indoor evaporator 23.

  A bypass passage 35 is provided in the air conditioning case 31 to flow the air that has passed through the indoor evaporator 23, bypassing the heater core and the indoor condenser 12, and is downstream of the air flow of the indoor evaporator 23. In addition, an air mix door 34 is disposed on the upstream side of the air flow of the heater core and the indoor condenser 12.

  The air mix door 34 adjusts the air volume ratio between the air volume passing through the heater core and the indoor condenser 12 and the air volume passing through the bypass passage 35 in the air after passing through the indoor evaporator 23, thereby condensing the indoor air. It is a flow rate adjusting unit that adjusts the flow rate of air flowing into the condenser 12 (in other words, the air volume), and functions to adjust the heat exchange capacity of the indoor condenser 12.

  On the downstream side of the air flow in the indoor condenser 12 and the bypass passage 35, the air heated by exchanging heat with the refrigerant in the indoor condenser 12 and the air that has not been heated through the bypass passage 35 merge. A space 36 is provided.

  In the most downstream portion of the air flow of the air conditioning case 31, an opening hole for blowing the air that has joined in the joining space 36 into the vehicle interior that is the space to be cooled is disposed. Specifically, as this opening hole, a defroster opening hole 37a that blows conditioned air toward the inner side surface of the vehicle front window glass, a face opening hole 37b that blows conditioned air toward the upper body of the passenger in the passenger compartment, and the feet of the passenger The foot opening hole 37c which blows air-conditioning wind toward is provided.

  Therefore, the air mix door 34 adjusts the air volume ratio between the air volume that passes through the indoor condenser 12 and the air volume that passes through the bypass passage 35, thereby adjusting the temperature of the air in the merge space 36. The air mix door 34 is driven by a servo motor (not shown) whose operation is controlled by a control signal output from the control device 40.

  Further, on the upstream side of the air flow of the defroster opening hole 37a, the face opening hole 37b, and the foot opening hole 37c, the opening areas of the defroster door 38a and the face opening hole 37b for adjusting the opening area of the defroster opening hole 37a are adjusted. A foot door 38c for adjusting the opening area of the face door 38b and the foot opening hole 37c is disposed.

  These defroster door 38a, face door 38b, and foot door 38c constitute an outlet mode switching unit that opens and closes each opening hole 37a to 37c and switches the outlet mode, and through a link mechanism or the like, It is driven by a servo motor (not shown) whose operation is controlled by a control signal output from the control device 40.

  In addition, the air flow downstream side of the defroster opening hole 37a, the face opening hole 37b, and the foot opening hole 37c is respectively connected to a face air outlet, a foot air outlet, and a defroster air outlet provided in the vehicle interior via ducts that form air passages. Connected to the exit.

  As the air outlet mode, the face opening hole 37b is fully opened and air is blown out from the face air outlet toward the upper body of the passenger in the vehicle. Both the face opening hole 37b and the foot opening hole 37c are opened. A bi-level mode that blows air toward the upper body and feet of an indoor occupant, a foot mode in which the foot opening hole 37c is fully opened and the defroster opening hole 37a is opened by a small opening, and air is mainly blown out from the foot outlet. is there.

  Next, the electric control unit of this embodiment will be described. The control device 40 is composed of a well-known microcomputer including a CPU, a ROM, a RAM and the like and its peripheral circuits, performs various calculations and processing based on an air conditioning control program stored in the ROM, and is connected to the output side. Various air conditioning control devices (specifically, compressor 11, high stage side expansion valve 13, liquid phase refrigerant side opening / closing valve 18a, blower fan 21, cooling expansion valve 22, low pressure side bypass passage opening / closing valve 26, high pressure side The operation of the bypass passage opening / closing valve 28a, the blower 32 and the like is controlled.

  On the input side of the control device 40, there are an inside air sensor that detects the temperature inside the vehicle, an outside air sensor that detects the outside air temperature, a solar radiation sensor that detects the amount of solar radiation inside the vehicle, and the temperature of air blown from the indoor evaporator 23 (in other words, An evaporator temperature sensor for detecting the evaporator temperature), a discharge pressure sensor for detecting the high-pressure refrigerant pressure discharged from the compressor 11, a condenser temperature sensor for detecting the temperature of the refrigerant flowing out of the indoor condenser 12, and the compressor 11 Various air-conditioning control sensor groups 41 such as a suction pressure sensor for detecting the suction refrigerant pressure sucked in are connected.

  An operation panel (not shown) disposed near the instrument panel in the front part of the vehicle interior is connected to the input side of the control device 40, and operation signals from various air conditioning operation switches provided on the operation panel are input. Specifically, various air conditioning operation switches provided on the operation panel include an operation switch of the vehicle air conditioner 1, a vehicle interior temperature setting switch for setting the vehicle interior temperature, a cooling operation mode, a dehumidifying heating operation mode, and a heating operation mode. A mode selection switch or the like for selecting is provided.

  The control device 40 is configured such that a control unit that controls the operation of various air-conditioning control devices connected to the output side thereof is integrally configured. However, the control device 40 is configured to control the operation of each control target device (specifically, Hardware and software) constitute a control unit that controls the operation of each control target device.

  For example, in the present embodiment, a configuration (specifically, hardware and software) that controls the operation of the electric motor of the compressor 11 constitutes the discharge capacity control unit. For example, in the present embodiment, the configuration (specifically, hardware and software) that controls the operation of the liquid-phase refrigerant side opening / closing valve 18a, the low pressure side bypass passage opening / closing valve 26, and the high pressure side bypass passage opening / closing valve 28a is refrigerant circuit control. Part. Of course, the discharge capacity control unit, the refrigerant circuit control unit, and the like may be configured as separate control devices for the control device 40.

  Next, the operation of the vehicle air conditioner 1 of the present embodiment having the above configuration will be described. In the vehicle air conditioner 1 of the present embodiment, as described above, switching to the cooling operation mode for cooling the vehicle interior, the heating operation mode for heating the vehicle interior, and the dehumidification heating mode for heating while dehumidifying the vehicle interior is possible. it can.

  Switching between these operation modes is performed by executing an air conditioning control program. This air conditioning control program is executed when the auto switch of the operation panel is turned on (in other words, turned on).

In the main routine of the air conditioning control program, the detection signals of the air conditioning control sensor group and the operation signals from various air conditioning operation switches are read. And based on the value of the read detection signal and operation signal, the target blowing temperature TAO which is the target temperature of the blowing air which blows off into the vehicle interior is calculated based on the following formula F1.
TAO = Kset × Tset−Kr × Tr−Kam × Tam−Ks × As + C (F1)
Here, Tset is the vehicle interior set temperature set by the temperature setting switch, Tr is the vehicle interior temperature detected by the internal air sensor (in other words, the internal air temperature), Tam is the external air temperature detected by the external air sensor, and As is solar radiation. The amount of solar radiation detected by the sensor. Kset, Kr, Kam, Ks are control gains, and C is a correction constant.

  Further, in the state where the cooling switch of the operation panel is turned on, when the target blowing temperature TAO is lower than the predetermined cooling reference temperature α, the operation in the cooling mode is executed. Also, when the target switch temperature TAO is equal to or higher than the cooling reference temperature α and the outside air temperature Tam is higher than the predetermined dehumidifying heating reference temperature β with the cooling switch on the operation panel turned on. The operation in the series dehumidifying and heating mode is executed.

  Further, when the target switch temperature TAO is equal to or higher than the cooling reference temperature α and the outside air temperature Tam is equal to or lower than the dehumidifying heating reference temperature β in a state where the cooling switch of the operation panel is turned on, the parallel operation is performed. Run in dehumidifying heating mode. When the cooling switch is not turned on, the operation in the heating mode is executed.

  With this air conditioning control program, the cooling mode is executed mainly when the outside air temperature is relatively high, such as in summer. The series dehumidifying heating mode is executed mainly in spring or autumn. The parallel dehumidifying heating mode is executed when the air needs to be heated with a higher heating capacity than the serial dehumidifying heating mode, mainly in early spring or late autumn. Furthermore, the heating mode can be executed mainly at low outdoor temperatures in winter.

(A) Cooling mode In the cooling mode, the control device 40 opens the high stage side expansion valve 13, opens the liquid phase refrigerant side opening / closing valve 18 a, and opens the cooling expansion valve 22 with a pressure reducing action. Further, the low pressure side bypass passage opening / closing valve 26 is closed, and the high pressure side bypass passage opening / closing valve 28a is closed.

  Thus, as shown in FIG. 1, in the cooling mode, the refrigerant circulates in the order of the compressor 11 → the outdoor heat exchanger 20 → the cooling expansion valve 22 → the indoor evaporator 23 → the constant pressure valve 27 → the accumulator 24 → the compressor 11. A vapor compression refrigeration cycle is configured.

  With this cycle configuration, the control device 40 controls the operation of the compressor 11 so that the air blown out from the indoor evaporator 23 becomes the target evaporator temperature TEO. The target evaporator temperature TEO is determined so as to decrease as the target outlet temperature TAO decreases. The target evaporator temperature TEO is determined within a range in which frost formation of the indoor evaporator 23 can be suppressed.

  Further, the control device 40 controls the operation of the cooling expansion valve 22 so that the COP of the cycle approaches the maximum value based on the pressure of the refrigerant flowing into the cooling expansion valve 22. Further, the control device 40 displaces the air mix door 34 so that the ventilation path on the indoor condenser 12 side is fully closed.

  In the refrigeration cycle apparatus in the cooling mode, the outdoor heat exchanger 20 functions as a radiator, and the indoor evaporator 23 functions as an evaporator. The heat absorbed from the air when the refrigerant evaporates in the indoor evaporator 23 is radiated to the outside air in the outdoor heat exchanger 20. Thereby, air can be cooled.

  Therefore, in the cooling mode, the vehicle interior can be cooled by blowing the air cooled by the indoor evaporator 23 into the vehicle interior.

(B) Series dehumidifying and heating mode In the series dehumidifying and heating mode, the control device 40 sets the high-stage expansion valve 13 to a throttled state that exerts a pressure reducing action, sets the liquid-phase refrigerant side on-off valve 18a to a fully open state, and sets the cooling expansion valve 22 is set to a throttle state that exerts a pressure reducing action, the low pressure side bypass passage opening / closing valve 26 is closed, and the high pressure side bypass passage opening / closing valve 28a is closed.

  As a result, as shown in FIG. 1, in the series dehumidifying and heating mode, the compressor 11 → the indoor condenser 12 → the high stage side expansion valve 13 → the outdoor heat exchanger 20 → the cooling expansion valve 22 → the indoor evaporator 23 → the constant. A vapor compression refrigeration cycle in which the refrigerant circulates in the order of the pressure valve 27 → accumulator 24 → compressor 11 is configured. That is, a refrigeration cycle in which the outdoor heat exchanger 20 and the indoor evaporator 23 are connected in series to the refrigerant flow is configured.

  In this cycle configuration, the control device 40 controls the operation of the compressor 11 as in the cooling mode. Further, the control device 40 controls the operations of the high-stage expansion valve 13 and the cooling expansion valve 22 based on the pressure of the refrigerant flowing into the high-stage expansion valve 13 so that the COP of the cycle approaches the maximum value. . At this time, the control device 40 decreases the throttle opening of the high stage side expansion valve 13 and increases the throttle opening of the cooling expansion valve 22 as the target blowing temperature TAO increases. In addition, the control device 40 displaces the air mix door 34 so that the ventilation path on the indoor condenser 12 side is fully opened.

  In the series dehumidifying heating mode, the indoor condenser 12 is caused to function as a radiator, and the indoor evaporator 23 is caused to function as an evaporator. Furthermore, when the saturation temperature of the refrigerant in the outdoor heat exchanger 20 is higher than the outside air, the outdoor heat exchanger 20 is caused to function as a radiator, and the saturation temperature of the refrigerant in the outdoor heat exchanger 20 is lower than the outside air. Makes the outdoor heat exchanger 20 function as an evaporator.

  For this reason, when the saturation temperature of the refrigerant in the outdoor heat exchanger 20 is higher than the outside air, the saturation temperature of the refrigerant in the outdoor heat exchanger 20 is lowered as the target blowing temperature TAO increases, and the outdoor heat exchanger 20 The amount of heat released from the refrigerant at 20 can be reduced. Thereby, the thermal radiation amount of the refrigerant | coolant in the indoor condenser 12 can be increased, and a heating capability can be improved.

  Further, when the saturation temperature of the refrigerant in the outdoor heat exchanger 20 is lower than the outside air, the saturation temperature of the refrigerant in the outdoor heat exchanger 20 is decreased as the target blowing temperature TAO rises, and the outdoor heat exchanger 20. The amount of heat absorbed by the refrigerant can be increased. Thereby, the thermal radiation amount of the refrigerant | coolant in the indoor condenser 12 can be increased, and a heating capability can be improved.

  Therefore, in the series dehumidifying heating mode, the air that has been cooled and dehumidified by the indoor evaporator 23 is reheated by the indoor condenser 12 and blown out into the vehicle interior, thereby performing dehumidification heating in the vehicle interior. . Furthermore, the heating capacity of the air in the indoor condenser 12 can be adjusted by adjusting the throttle opening degree of the high stage side expansion valve 13 and the cooling expansion valve 22.

(C) Parallel dehumidifying and heating mode In the parallel dehumidifying and heating mode, the control device 40 sets the high-stage side expansion valve 13 to a throttled state that exerts a pressure reducing action, sets the liquid-phase refrigerant side on-off valve 18a to a fully open state, and sets the cooling expansion valve. 22 is set to a throttle state that exerts a pressure reducing action, the low pressure side bypass passage opening / closing valve 26 is fully opened, and the high pressure side bypass passage opening / closing valve 28a is fully opened.

  As a result, as shown in FIG. 2, in the parallel dehumidifying heating mode, the refrigerant circulates in the order of the compressor 11 → the indoor condenser 12 → the high stage side expansion valve 13 → the outdoor heat exchanger 20 → the accumulator 24 → the compressor 11. At the same time, a vapor compression refrigeration cycle is formed in which the refrigerant circulates in the order of the compressor 11 → the indoor condenser 12 → the cooling expansion valve 22 → the indoor evaporator 23 → the constant pressure valve 27 → the accumulator 24 → the compressor 11. That is, a refrigeration cycle in which the outdoor heat exchanger 20 and the indoor evaporator 23 are connected in parallel to the refrigerant flow is configured.

  In this cycle configuration, the control device 40 controls the operation of the compressor 11 as in the cooling mode. Further, the control device 40 controls the operations of the high-stage expansion valve 13 and the cooling expansion valve 22 based on the pressure of the refrigerant flowing into the high-stage expansion valve 13 so that the COP of the cycle approaches the maximum value. . At this time, the control device 40 decreases the throttle opening of the high stage side expansion valve 13 and increases the throttle opening of the cooling expansion valve 22 as the target blowing temperature TAO increases. In addition, the control device 40 displaces the air mix door 34 so that the ventilation path on the indoor condenser 12 side is fully opened.

  In the parallel dehumidifying and heating mode, the indoor condenser 12 is caused to function as a radiator, and the outdoor heat exchanger 20 and the indoor evaporator 23 are caused to function as an evaporator. For this reason, the refrigerant | coolant saturation temperature of the outdoor heat exchanger 20 can be lowered | hung with the raise of the target blowing temperature TAO, and the heat absorption amount of the refrigerant | coolant in the outdoor heat exchanger 20 can be increased. Thereby, the thermal radiation amount of the refrigerant | coolant in the indoor condenser 20 can be increased, and a heating capability can be improved.

  Accordingly, in the parallel dehumidifying and heating mode, the air that has been cooled and dehumidified by the indoor evaporator 23 is reheated by the indoor condenser 12 and blown out into the vehicle interior, thereby performing dehumidification heating in the vehicle interior. . Furthermore, the refrigerant saturation temperature (in other words, the evaporation temperature) in the outdoor heat exchanger 20 can be made lower than the refrigerant saturation temperature (in other words, the evaporation temperature) in the indoor evaporator 23. The air heating capacity can be increased.

(D) Heating Mode In the heating mode, the control device 40 sets the high stage side expansion valve 13 to a throttle state that exerts a pressure reducing action, sets the liquid phase refrigerant side on-off valve 18a to a closed state, and closes the cooling expansion valve 22. Further, the low pressure side bypass passage opening / closing valve 26 is fully opened, and the high pressure side bypass passage opening / closing valve 28a is closed.

  Thus, as shown in FIG. 3, in the heating mode, the discharge port 11 c of the compressor 11 → the indoor condenser 12 → the high-stage side expansion valve 13 → the liquid-phase refrigerant outflow port 14 c of the gas-liquid separator 14 → the fixed throttle 17. The refrigerant circulates in the order of the outdoor heat exchanger 20 → the suction port 11 a of the compressor 11, and the refrigerant circulates in the order of the gas-phase refrigerant outflow port 14 b of the gas-liquid separator 14 → the intermediate pressure port 11 b of the compressor 11. A so-called gas injection cycle is configured.

  With this cycle configuration, the control device 40 controls the operation of the compressor 11 so that the refrigerant flowing into the indoor condenser 12 reaches the target condenser temperature TCO. The target condenser temperature TCO is determined so as to increase as the target blowing temperature TAO increases. Furthermore, the control device 40 controls the operation of the high stage side expansion valve 13 so that the COP of the cycle approaches the maximum value based on the pressure of the refrigerant flowing into the high stage side expansion valve 13. In addition, the control device 40 displaces the air mix door 34 so that the ventilation path on the indoor condenser 12 side is fully opened.

  In the refrigeration cycle apparatus in the heating mode, the indoor condenser 12 functions as a radiator, and the outdoor heat exchanger 20 functions as an evaporator. Then, the heat absorbed from the outside air when the refrigerant evaporates in the outdoor heat exchanger 20 is radiated to the air in the indoor condenser 12. Thereby, air can be heated.

  Therefore, in the heating mode, the vehicle interior can be heated by blowing the air heated by the indoor condenser 12 into the vehicle interior.

  In the vehicle air conditioner 1 of the present embodiment, as described above, by switching the refrigerant flow path of the heat pump cycle 10, various cycle configurations can be realized, and appropriate cooling, heating, and dehumidifying heating in the vehicle interior can be realized. .

  Furthermore, in the vehicle air conditioner 1 applied to a hybrid vehicle as in this embodiment, engine waste heat may be insufficient as a heating heat source. Therefore, it is extremely effective that a high COP can be exhibited regardless of the heating load in the heating operation mode as in the heat pump cycle 10 of the present embodiment.

  In the present embodiment, since a differential pressure valve that is displaced by a pressure difference is employed as the gas-phase refrigerant side on-off valve 16, there is no need to provide an electromagnetic mechanism or the like for displacing the gas-phase refrigerant side on-off valve 16. By controlling the operation of the phase refrigerant side on / off valve 18a, the gas phase refrigerant side on / off valve 16 can be easily displaced to open and close the intermediate pressure refrigerant passage 15.

  More specifically, when the liquid-phase refrigerant side on-off valve 18a opens the fixed throttle bypass passage 18, at least one of the indoor condenser 12 and the outdoor heat exchanger 20 functions as a radiator that radiates the refrigerant. At the same time, the indoor evaporator 23 can be switched to a cycle configuration that functions as an evaporator for evaporating the refrigerant.

  On the other hand, when the liquid-phase refrigerant-side on-off valve 18a closes the fixed throttle bypass passage 18, the indoor condenser 12 functions as a radiator that radiates the refrigerant, and the outdoor heat exchanger 20 evaporates the refrigerant. It is possible to easily configure a heat pump cycle configured to be switchable to a cycle configuration as a gas injection cycle that functions as a gas injection cycle.

  When it is determined to stop the operation of the heat pump cycle 10 in the heating mode, the control device 40 performs compressor stop delay control for delaying the stop of the compressor 11. The case where it is determined to stop the operation of the heat pump cycle 10 is, for example, a case where the air conditioning stop switch on the operation panel is pressed, or a case where the ignition switch of the vehicle is turned off.

  Specifically, as shown in the time chart of FIG. 4, when it is determined that the operation of the heat pump cycle 10 is stopped in the heating mode, the control device 40 first opens the liquid-phase refrigerant side on-off valve 18a. . As a result, the liquid-phase refrigerant separated by the gas-liquid separator 14 bypasses the fixed throttle 17, flows through the fixed throttle bypass passage 18, and flows to the outdoor heat exchanger 20, so that the refrigerant pressure in the pressure introduction passage 19 increases. Thus, the differential pressure between the refrigerant pressure in the intermediate pressure refrigerant passage 15 and the refrigerant pressure in the pressure introduction passage 19 is reduced. As a result, the opening degree of the gas-phase refrigerant side opening / closing valve 16 is reduced.

  The compressor 11 is stopped after a predetermined time has elapsed since the liquid-phase refrigerant side opening / closing valve 18a was opened. Thereby, even if the compressor 11 is stopped, the gas-phase refrigerant separated by the gas-liquid separator 14 passes through the gas-phase refrigerant-side on-off valve 16 and flows into the compressor 11 from the intermediate pressure port 11b, and the suction port 11a. Backflowing to the side can be suppressed.

  For example, the predetermined time is 600 ms. Since the differential pressure between the refrigerant pressure in the intermediate pressure refrigerant passage 15 and the refrigerant pressure in the pressure introduction passage 19 becomes smaller as the predetermined time is longer, the reverse flow of the refrigerant in the compressor 11 can be further suppressed.

  The control device 40 has an abnormality in the compressor 11 during the compressor stop delay control (specifically, from when the liquid-phase refrigerant side on-off valve 18a is opened until a predetermined time elapses). In such a case, the compressor 11 is stopped urgently. For example, when the drive voltage of the compressor 11 is out of the normal range, it is determined that an abnormality has occurred in the compressor 11.

  According to this, a safety function can be provided against delaying the stop of the compressor 11. For example, when the air conditioning stop switch on the operation panel is pressed during maintenance or the ignition switch of the vehicle is turned off, the compressor 11 may be mistakenly stopped and may touch the compressor 11 or its peripheral devices. Therefore, in such a case, safety can be ensured by urgently stopping the compressor 11.

  In the present embodiment, the control device 40 performs compressor stop delay control when it is determined to stop the compressor 11. Specifically, in the compressor stop delay control, the control device 40 stops the compressor 11 after controlling the liquid-phase refrigerant side on-off valve 18a so that the amount of decompression of the refrigerant decreases. For example, in the compressor stop delay control, the control device 40 stops the compressor 11 when a predetermined time elapses after controlling the liquid-phase refrigerant side opening / closing valve 18a so that the amount of decompression of the refrigerant decreases.

  According to this, since the pressure reduction of the refrigerant in the fixed throttle 17 is reduced, the pressure of the low-pressure refrigerant on the suction port 11a side is increased, so that the pressure difference between the intermediate pressure port 11b and the suction port 11a is reduced.

  Therefore, when the compressor 11 is stopped, it is possible to suppress the gas-phase refrigerant separated by the gas-liquid separator 14 from flowing through the differential pressure valve 16 to the low pressure side of the compressor 11. As a result, it is possible to prevent the compressor 11 from rotating backward and generating vibrations and abnormal noise.

  In the present embodiment, the control device 40 urgently stops the compressor 11 when an abnormality occurs in the compressor 11 during the compressor stop delay control. According to this, a safety function can be provided against delaying the stop of the compressor 11.

(Other embodiments)
The above-described embodiment can be variously modified as follows.

  (1) Although the example which applied the heat pump cycle 10 to the vehicle air conditioner 1 of a hybrid vehicle was demonstrated in the above-mentioned embodiment, the heat pump cycle 10 is used for vehicle travel in this embodiment, for example. You may apply to the vehicle air conditioner 1 of the electric vehicle which obtains the driving force for vehicle travel from an electric motor. The heat pump cycle 10 may be applied to a stationary air conditioner or the like.

  (2) In the above-described embodiment, the gas-liquid separator 14, the gas-phase refrigerant side on-off valve 16, the fixed throttle 17, the fixed throttling bypass passage 18, the liquid-phase refrigerant side on-off valve 18 a, and the pressure introduction passage 19 are integrally configured. The integrated valve may be used.

  This integrated valve is an integral part of the components required to make the heat pump cycle 10 function as a gas injection cycle, and further, a refrigerant circuit switching unit that switches a refrigerant circuit of refrigerant circulating in the cycle It fulfills the function as.

  (3) In the above-described embodiment, the example in which each operation mode is switched by executing the air conditioning control program has been described. However, the switching of each operation mode is not limited to this. For example, each operation mode may be switched on the basis of the target blowing temperature TAO and the outside air temperature Tam with reference to a control map stored in advance in the control device.

  In addition, an operation mode setting switch for setting each operation mode is provided on the operation panel, and the cooling mode, the series dehumidifying heating mode, the parallel dehumidifying heating mode, and the heating mode are switched according to an operation signal of the operation mode setting switch. Also good.

  (4) In the compressor stop delay control of the above-described embodiment, the compressor 11 is stopped after a predetermined time has elapsed since the liquid-phase refrigerant side opening / closing valve 18a is opened, but the liquid-phase refrigerant side opening / closing valve 18a is opened. After the valve operation, the compressor 11 may be stopped when the differential pressure between the refrigerant pressure in the intermediate pressure refrigerant passage 15 and the refrigerant pressure in the pressure introduction flow path 19 becomes smaller than a threshold value.

11 Compressor 11a Suction port 11b Intermediate pressure port 11c Discharge port 12 Indoor condenser (high-pressure side heat exchanger)
13 High stage expansion valve (High pressure side pressure reducing part)
14 Gas-liquid separator (gas-liquid separator)
15 Gas Phase Refrigerant Passage 16 Gas Phase Refrigerant Side Open / Close Valve (Differential Pressure Valve)
17 Fixed throttle (low-stage decompression section)
18 Fixed-throttle bypass passage (low-stage decompression section, adjustment mechanism)
18a Liquid-phase refrigerant-side on-off valve (low-stage decompression section, adjustment mechanism)
20 Outdoor heat exchanger (evaporator)
40 Control device (control unit)

Claims (3)

A compressor (11) that sucks and compresses refrigerant from the suction port (11a) and discharges it from the discharge port (11c);
A high pressure side heat exchanger (12) for exchanging heat of the refrigerant discharged from the discharge port;
A high-stage decompression section (13) for decompressing the refrigerant flowing out of the high-pressure heat exchanger,
A gas-liquid separator (14) for separating the gas-liquid of the refrigerant decompressed by the high-stage decompression unit;
A lower-stage decompression section (17, 18, 18a) for decompressing the refrigerant in the liquid phase separated by the gas-liquid separation section;
An evaporator (20) for evaporating the refrigerant decompressed in the low-stage decompression unit;
A gas-phase refrigerant passage (15) through which the gas-phase refrigerant separated by the gas-liquid separation unit flows;
A differential pressure valve (16) for opening and closing the gas-phase refrigerant passage by a pressure difference between the refrigerant decompressed by the low-stage decompression section and the refrigerant flowing through the gas-phase refrigerant passage;
The compressor has an intermediate pressure port (11b) through which the refrigerant that has flowed through the gas-phase refrigerant passage flows, and the refrigerant that has flowed from the intermediate pressure port is sucked from the suction port. To join
The low-stage decompression unit has an adjustment mechanism (18, 18a) for adjusting the decompression amount of the refrigerant,
Further, when it is determined to stop the compressor, a control unit that performs compressor stop delay control that stops the compressor after controlling the low-stage decompression unit so that the amount of decompression of the refrigerant decreases. A refrigeration cycle apparatus comprising (40).   2. The control unit according to claim 1, wherein, in the compressor stop delay control, the control unit stops the compressor when a predetermined time elapses after controlling the low-stage decompression unit so that the decompression amount of the refrigerant decreases. Refrigeration cycle equipment.   3. The refrigeration cycle apparatus according to claim 1, wherein, when an abnormality occurs in the compressor while the compressor stop delay control is performed, the control unit urgently stops the compressor.

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