WO2018088034A1

WO2018088034A1 - Refrigeration cycle device

Info

Publication number: WO2018088034A1
Application number: PCT/JP2017/033619
Authority: WO
Inventors: 浩太郎福田
Original assignee: 株式会社デンソー
Priority date: 2016-11-09
Filing date: 2017-09-18
Publication date: 2018-05-17
Also published as: JP2018077003A

Abstract

This refrigeration cycle device is provided with pressure pulsation reduction units (15b, 15c, 15d) that reduce pressure pulsation of a refrigerant in a gas-phase refrigerant path (15). One example of the pressure pulsation reductions units is a muffler (15b) that increases the cross-sectional area of the gas-phase refrigerant path and that is arranged between a hose (15a) and a differential pressure valve (16) in the gas-phase refrigerant path (15). Other examples of the pressure pulsation reduction units include resonators (15c, 15d) that form a resonance space and that are connected between the hose (15a) and an intermediate pressure port (11b) in the gas-phase refrigerant path (15).

Description

Refrigeration cycle equipment

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2016-218791 filed on Nov. 9, 2016, the disclosure of which is incorporated into this application by reference.

This disclosure relates to a refrigeration cycle apparatus including a two-stage compression type compressor.

Conventionally, Patent Document 1 describes a refrigeration cycle apparatus that performs gas injection in a heating mode and does not perform gas injection in an operation mode other than the heating mode.

This refrigeration cycle apparatus includes 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, and dissipates heat by exchanging heat with the air blown into the passenger compartment. Thereby, the air blown into the passenger compartment is heated.

The refrigerant that has flowed out of the indoor condenser is decompressed and expanded in an enthalpy manner until it becomes an intermediate-pressure refrigerant by a 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 enthalpy 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 that has flowed out of the outdoor heat exchanger is sucked from the suction port of the compressor and compressed again.

On the other hand, the gas-phase refrigerant separated by the gas-liquid separator flows into the intermediate pressure port side of the compressor through the gas-phase refrigerant passage. The differential pressure valve disposed in the gas-phase refrigerant passage opens and closes according to the pressure difference between the gas-phase refrigerant separated by the gas-liquid separator and the pressure of the refrigerant flowing into the outdoor heat exchanger. In the heating mode, since the low-pressure refrigerant decompressed by the fixed throttle flows into the outdoor heat exchanger, the pressure between the gas-phase refrigerant separated by the gas-liquid separation unit and the pressure of the refrigerant flowing into the outdoor heat exchanger The difference increases and the differential pressure valve opens.

The intermediate-pressure gas-phase refrigerant flowing into the intermediate pressure port of the compressor joins with the refrigerant sucked from the compressor intake port and compressed by the low-stage compression mechanism, and is compressed by the high-stage compression mechanism. That is, 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 flown 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.

By configuring the gas injection cycle, the high-stage compression mechanism of the compressor can be sucked with the low-temperature mixed refrigerant, the compression efficiency of the high-stage compression mechanism can be improved, and the low-stage side By reducing the pressure difference between the suction refrigerant pressure and the discharge refrigerant pressure in both the compression mechanism and the high-stage compression mechanism, 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.

In operation modes other than the heating mode (for example, the cooling mode or the dehumidifying heating mode), the liquid-phase refrigerant separated in the gas-liquid separation unit flows around the fixed throttle and flows into the outdoor heat exchanger. As a result, the pressure difference between the gas-phase refrigerant separated in the gas-liquid separation unit and the pressure of the refrigerant flowing into the outdoor heat exchanger is reduced and the differential pressure valve is closed. The gas phase refrigerant thus made does not flow into the intermediate pressure port side of the compressor. Thereby, in the operation modes other than the heating mode (in other words, the operation mode in which the difference between the high and low pressures of the cycle is small), the gas injection cycle is not configured.

JP2013-92355A

In the above prior art, the gas-phase refrigerant passage for introducing the gas-phase refrigerant separated in the gas-liquid separation section to the intermediate pressure port side of the compressor is opened and closed by the differential pressure valve displaced by the pressure difference. The structure can be simplified as compared with the case where the valve is opened and closed by an electromagnetic mechanism, and the risk that the opening and closing of the gas-phase refrigerant passage becomes impossible due to an electrical failure can be reduced.

However, according to the detailed examination of the present inventor, in the above prior art, the differential pressure valve is displaced due to the pressure difference. Therefore, the differential pressure valve is displaced by the pressure pulsation generated in the compressor or the like, and abnormal noise or unexpected. It was found that vibration may occur.

In view of the above points, the present disclosure is based on pressure pulsation in a refrigeration cycle apparatus that opens and closes a gas-phase refrigerant passage for introducing a gas-phase refrigerant separated in a gas-liquid separation unit to an intermediate pressure port side of a compressor by a differential pressure valve. The purpose is to suppress the occurrence of abnormal noise and unexpected vibration.

A refrigeration cycle apparatus according to one feature example of the present disclosure includes:
A compressor that sucks and compresses refrigerant from the suction port and discharges it from the discharge port;
A high-pressure side heat exchanger that exchanges heat between the refrigerant discharged from the discharge port;
A high-stage decompression section that decompresses the refrigerant flowing out of the high-pressure side heat exchanger;
A gas-liquid separation unit that separates the gas-liquid of the refrigerant decompressed by the high-stage decompression unit;
A low-stage decompression unit that decompresses the liquid-phase refrigerant separated in the gas-liquid separation unit;
An evaporator for evaporating the refrigerant decompressed in the low-stage decompression unit;
A gas-phase refrigerant passage through which a gas-phase refrigerant separated in the gas-liquid separation unit flows;
A differential pressure valve that opens and closes the gas-phase refrigerant passage by a pressure difference between the refrigerant decompressed by the low-stage decompression unit and the refrigerant flowing through the gas-phase refrigerant passage.
In the refrigeration cycle apparatus, the compressor has an intermediate pressure port through which the refrigerant flowing through the gas-phase refrigerant passage flows in, and merges the refrigerant flowing in from the intermediate pressure port with the refrigerant in the compression process sucked from the suction port. It ’s like that. The refrigeration cycle apparatus further includes a pressure pulsation reducing unit that reduces the pressure pulsation of the refrigerant in the gas-phase refrigerant passage.

According to this, since the pressure pulsation of the refrigerant in the gas phase refrigerant passage can be reduced by the pressure pulsation reducing unit, it is possible to suppress the generation of abnormal noise and unexpected vibration due to the pressure pulsation displacing the differential pressure valve.

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.

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 serves to cool or heat the air blown into the vehicle interior, which 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 circuit shown in FIG. 1, the serial dehumidifying and heating mode shown in FIG. 1, the parallel dehumidifying and heating mode shown in FIG. 2, or the heating mode shown in FIG. 1 to 3, the flow of the refrigerant in each operation mode is indicated by solid arrows.

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 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.

Compressor 11 of heat pump cycle 10 sucks in 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 the present embodiment, the compressor 11 in which two compression mechanisms are accommodated in one housing is adopted, but the type of the 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 exerted. 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.

The intermediate pressure port 11 b of the compressor 11 is connected to the gas phase refrigerant outflow port 14 b of the gas-liquid separator 14 via the 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 on-off 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 opening / closing 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.

The intermediate part of the intermediate pressure refrigerant passage 15 is constituted by a hose 15a. The hose 15a is formed of a flexible material. Both end portions of the intermediate pressure refrigerant passage 15 are formed of piping. The pipe is formed of a hard material such as metal.

A muffler 15b is disposed in a portion of the intermediate pressure refrigerant passage 15 closer to the gas-phase refrigerant side on-off valve 16 than the hose 15a. The muffler 15 b is a pressure pulsation reducing unit that reduces the pressure pulsation of the refrigerant by increasing the cross-sectional area of the intermediate pressure refrigerant passage 15. The muffler 15b reduces the pressure pulsation of the refrigerant over a wide frequency range.

Resonators

15c and 15d are connected to the intermediate pressure port 11b side of the compressor 11 with respect to the hose 15a in the intermediate pressure refrigerant passage 15. The

resonators

15 c and 15 d are pressure pulsation reducing units that reduce the pressure pulsation of the refrigerant by forming a resonance space branched from the intermediate pressure refrigerant passage 15. The

resonators

15c and 15d reduce the pressure pulsation of the refrigerant in a frequency range narrower than that of the muffler 15b. Both

resonators

15c and 15d have different volumes, and reduce the pressure pulsation of the refrigerant in different frequency ranges.

On the other hand, the inlet side of the fixed throttle 17 is connected to the liquid-phase refrigerant outlet port 14 c of the gas-liquid separator 14, and the refrigerant inlet side of the outdoor heat exchanger 20 is connected to the outlet side of the fixed throttle 17. 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 refrigerant on the upstream side of the fixed throttle increases as the required circulating refrigerant flow rate that requires circulation of 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 opening / closing 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 side on-off valve 18a can switch the refrigerant flow path of the heat pump cycle 10. 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 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 inlet side of the cooling expansion valve 22 as the second decompression unit is connected to the refrigerant outlet side of the outdoor heat exchanger 20. 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 inlet side of the accumulator 24 is connected to the outlet side of the indoor evaporator 23. 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.

Therefore, the refrigerant flowing 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 through 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. .

The high pressure side bypass passage 28 is provided with a high pressure side bypass passage opening / closing valve 28a. 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.

Inside / outside air switching device 33 for switching between the inside air and the outside air is arranged on the most upstream side of the air flow of air conditioning case 31. 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.

A blower 32 that blows the air sucked through the inside / outside air switching device 33 toward the vehicle interior is arranged on the downstream side of the air flow of the inside / outside air switching device 33. 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 arranged 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 part of the air flow of the air conditioning case 31, an opening hole through which the air merged in the merge space 36 is blown out into the vehicle interior which is the space to be cooled is arranged. 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 merging 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.

The defroster door 38a, the face door 38b, and the foot door 38c constitute an air outlet mode switching unit that opens and closes the respective opening holes 37a to 37c and switches the air outlet mode. 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.

The input side of the control device 40 is connected to an operation panel (not shown) disposed near the instrument panel in the front of the passenger compartment, 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 this 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.

These switching of each operation mode 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.

Furthermore, 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 when the outside air temperature is relatively high, mainly 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.

In 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 the parallel dehumidifying and heating mode, the indoor condenser 12 functions as a radiator, and the outdoor heat exchanger 20 and the indoor evaporator 23 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 12 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.

As a result, as shown in FIG. 3, in the heating mode, the discharge port 11c of the compressor 11 → the indoor condenser 12 → the high stage side expansion valve 13 → the liquid phase refrigerant outlet 14c 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 outlet 14 b of the gas-liquid separator 14 → the intermediate pressure port 11 b of the compressor 11. An injection cycle is configured.

In this cycle configuration, the control device 40 controls the operation of the compressor 11 so that the refrigerant flowing into the indoor condenser 12 becomes 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.

Accordingly, 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 the 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.

Since the intermediate pressure refrigerant passage 15 is provided with the muffler 15b and the

resonators

15c and 15d, even if the pressure pulsation of the refrigerant generated in the compressor 11 is propagated to the intermediate pressure refrigerant passage 15 via the intermediate pressure port 11b. The pressure pulsation of the refrigerant in the intermediate pressure refrigerant passage 15 can be reduced. Therefore, it is possible to suppress the generation of abnormal noise or unexpected vibration due to the pressure pulsation of the refrigerant moving the gas-phase refrigerant side on-off valve 16.

Since the muffler 15b that reduces the pressure pulsation of the refrigerant over a wide frequency range is disposed in the intermediate pressure refrigerant passage 15 at a position closer to the gas-phase refrigerant side opening / closing valve 16 than the hose 15a, the refrigerant generated in the compressor 11 Even if the pressure pulsation is amplified by elastic deformation of the hose 15a, the pressure pulsation of the refrigerant can be satisfactorily reduced.

Resonators

15c and 15d that reduce the pressure pulsation of the refrigerant in a narrow frequency range are connected to the intermediate pressure port 11b side of the compressor 11 in the intermediate pressure refrigerant passage 15 relative to the hose 15a. The pressure pulsation of the refrigerant in a specific frequency range can be satisfactorily reduced by the

resonators

15c and 15d before the form of the pressure pulsation of the refrigerant changed by the elastic deformation of the hose 15a.

In the present embodiment, the muffler 15b and the

resonators

15c and 15d reduce the pressure pulsation of the refrigerant in the gas-phase refrigerant passage 15, so that the gas-phase refrigerant side on-off valve 16 is displaced by the pressure pulsation, causing abnormal noise and unexpected vibrations. Can be prevented from occurring.

In the present embodiment, the muffler 15 b is disposed between the hose 15 a and the gas-phase refrigerant side on-off valve 16 in the gas-phase refrigerant passage 15.

According to this, since a part of the gas-phase refrigerant passage 15 is formed by the flexible hose 15a, the pressure pulsation generated in the compressor 11 may be amplified by the hose 15a. Since the pressure pulsation amplified in step S3 can be reduced by the muffler 15b, the pressure pulsation propagating from the compressor 11 to the gas-phase refrigerant side on-off valve 16 can be effectively reduced.

In this embodiment, the

resonators

15c and 15d are connected between the hose 15a and the intermediate pressure port 11b in the gas-phase refrigerant passage 15.

According to this, since a part of the gas-phase refrigerant passage 15 is formed by the flexible hose 15a, the pressure pulsation generated in the compressor 11 may change in the hose 15a. Since the pressure pulsation can be reduced by the

resonators

15c and 15d before the form of the pressure pulsation generated in the machine 11 is changed by the hose 15a, the pressure pulsation propagating from the compressor 11 to the gas-phase refrigerant side on-off valve 16 is effective. Can be reduced.

(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, an example in which each operation mode is switched by executing an air conditioning control program has been described, but switching between 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 above-described embodiment, the pressure pulsation of the refrigerant is reduced by the muffler 15b and the

resonators

15c and 15d. Good.

Further, the hose 15a may be provided with a pressure pulsation reducing function. For example, a pulsation absorbing hose having a mechanism such as an inner tube may be used as the hose 15a.

Claims

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) 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. Configured to join,
Furthermore, a refrigeration cycle apparatus comprising a pressure pulsation reducing unit (15b, 15c, 15d) for reducing pressure pulsation of the refrigerant in the gas-phase refrigerant passage.
A hose (15a) that is formed of a flexible material and forms part of the gas-phase refrigerant passage,
The pressure pulsation reducing unit is a muffler (15b) that expands a cross-sectional area of the gas-phase refrigerant passage, and is disposed between the hose and the differential pressure valve in the gas-phase refrigerant passage. The refrigeration cycle apparatus described.
The refrigeration according to claim 2, wherein the pressure pulsation reducing unit is a resonator (15c, 15d) that forms a resonance space, and is connected between the hose and the intermediate pressure port in the gas-phase refrigerant passage. Cycle equipment.
A hose (15a) that is formed of a flexible material and forms part of the gas-phase refrigerant passage,
The refrigeration according to claim 1, wherein the pressure pulsation reducing unit is a resonator (15c, 15d) that forms a resonance space, and is connected between the hose and the intermediate pressure port in the gas-phase refrigerant passage. Cycle equipment.