Heat pump circuit device

Abstract

A heat pump circuit device comprises: a compressor (11); a branch section (12a); a heating unit (13, 30, 131) configured to heat a heating object using refrigerant branched off at the branch section as a heat source; a heating unit-side decompression unit (14a, 14b, 14c) configured to decompress the refrigerant exiting the heating unit; a bypass passage (21c) through which further refrigerant, branched off at the branch section, flows; a bypass-side flow rate control unit (14d); and a junction section (12f). If the length of an intake-side flow path (21d) from an outlet port of the junction section to an intake port of the compressor is defined as an intake-side flow path length L1, then the intake-side flow path length L1 is equal to or longer than an expansion gap Lv.The expansion distance Lv is a flow length that is necessary to bring the refrigerant mixed in the merging section (12f) into a homogeneous state.

Description

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is based on Japanese Patent Application No. 2022-024884, filed on February 21, 2022, the contents of which are incorporated herein by reference in their entirety. FIELD OF THE INVENTION

[0002] The present disclosure relates to a heat pump cycle device configured to mix refrigerants having different enthalpies and draw the mixed refrigerant into a compressor. STATE OF THE ART

[0003] Conventionally, Patent Literature 1 discloses a heat pump cycle device applied to a vehicle air conditioner. In the heat pump cycle device of Patent Literature 1, operation is performed in a hot gas air heating mode by switching refrigerant circuits to heat the air in the vehicle cabin at a time of extremely low outside air temperature.

[0004] In a refrigerant cycle of the hot gas air heating mode disclosed in Patent Literature 1, a flow of discharge refrigerant discharged from a compressor is branched at a branch portion, and the branched refrigerant is caused to flow into a heating unit. The heating unit heats ventilation air through heat exchange between the refrigerant and the ventilation air to be blown into the vehicle cabin. Furthermore, the refrigerant flowing out of the heating unit is decompressed by a heating unit-side decompression unit. The other refrigerant branched at the branch portion is caused to flow into a bypass passage. Furthermore, the refrigerant flowing into the bypass passage is decompressed by a bypass-side flow rate control valve.

[0005] The two-phase gas-liquid refrigerant with low enthalpy decompressed by the heating unit-side decompression unit and the gas-phase refrigerant with relatively low enthalpy decompressed by the bypass-side flow rate control valve are mixed by a mixing unit and sucked into the compressor. That is, in the heat pump cycle device of Patent Literature 1, during the hot gas air heating mode, the refrigerant circuit is switched to a refrigerant circuit in which refrigerants with different enthalpies are mixed in the mixing unit and sucked into the compressor.

[0006] Furthermore, Patent Literature 1 also discloses a mixing unit that mixes refrigerants with different enthalpies to achieve a homogeneous state. Therefore, in the heat pump cycle device of Patent Literature 1, the liquid compression of the compressor is limited in the hot gas air heating mode to protect the compressor. CITATION LISTPATENT LITERATURE

[0007] Patent Document 1: JP-2021-156567-A SUMMARY OF THE INVENTION

[0008] However, if the mixing unit of Patent Literature 1 is used, the size of the entire heat pump cycle device is likely to increase, and the mountability of the heat pump cycle device is likely to deteriorate. As a result, the productivity of the heat pump cycle device is likely to deteriorate.

[0009] In view of the above, it is an object of the present disclosure to provide a heat pump cycle device configured to mix refrigerants having different enthalpies and draw the mixed refrigerant into a compressor, and capable of protecting the compressor and preventing deterioration of productivity.

[0010] A heat pump cycle device according to one aspect of the present disclosure includes a compressor, a branch section, a heating unit, a heating unit-side decompression unit, a bypass passage, a bypass-side flow rate control unit, and a merging section.

[0011] The compressor is configured to compress and discharge a refrigerant. The branch portion is configured to branch a flow of the refrigerant discharged from the compressor. The heating unit is configured to heat a heating object using a refrigerant branched at the branch portion as a heat source. The heating-unit-side decompression unit is configured to decompress the refrigerant flowing out of the heating unit. The bypass passage is provided through which another refrigerant branched at the branch portion flows. The bypass-side flow rate control unit is configured to control a flow rate of the refrigerant flowing through the bypass passage.The joining portion is configured to join a flow of heating unit side refrigerant flowing out of the heating unit side decompression unit and a flow of bypass side refrigerant flowing out of the bypass side flow rate control unit and to cause a joined refrigerant to flow to a suction port of the compressor.

[0012] When a length of a suction-side flow path from a discharge port of the merging portion to the suction port of the compressor is defined as a suction-side flow path length L1, the suction-side flow path length L1 is equal to or greater than a relaxation distance Lv.

[0013] The relaxation distance Lv is defined by the following formula 1. Lv=ρL×dp218μg×Uv

[0014] In Formula 1, ρL is a density of droplets which are particles of a liquid-phase refrigerant contained in the refrigerant at a junction MX of the heating unit-side refrigerant and the bypass-side refrigerant in the junction portion, dp is an average diameter of the droplets, µg is a viscosity of a gas-phase refrigerant contained in the refrigerant at the junction MX, and Uv is an average flow velocity of the droplets and the gas-phase refrigerant at the junction MX.

[0015] Since the suction-side flow path length L1 is equal to or greater than the expansion distance Lv, the refrigerant drawn into the compressor can be homogenized, as described later in embodiments. Thus, uneven distribution of the liquid-phase refrigerant in the suction refrigerant can be prevented, and the compressor can be protected.

[0016] The suction-side flow path length L1 can be easily controlled by changing the length of a refrigerant pipe connecting the outlet port of the merging section and the suction port of the compressor. Therefore, the productivity of the heat pump cycle device is less affected by making the suction refrigerant homogeneous.

[0017] Therefore, according to the heat pump cycle device according to the aspect of the present disclosure, even in a heat pump cycle device that mixes refrigerants having different enthalpies and draws the mixed refrigerant into a compressor, it is possible to protect the compressor and prevent deterioration of productivity.

[0018] Here, the refrigerant in a homogeneous state can be defined as a refrigerant whose temperature and velocity have reached an equilibrium state, and whose temperature distribution and velocity distribution have been sufficiently suppressed. In a case where the homogeneous state of the refrigerant combined at the combining section is a two-phase gas-liquid refrigerant, the refrigerant can be defined as a refrigerant in which the droplets contained in the refrigerant are uniformly distributed in the gas-phase refrigerant, and the temperature distribution and velocity distribution between the droplets and the gas-phase refrigerant are sufficiently suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. Fig. 1 is a schematic overall configuration diagram of a vehicle air conditioner of a first embodiment; Fig. 2 is a schematic sectional view showing a joining portion of the first embodiment; Fig. 3 is a diagram showing a change of an average velocity UL in an acceleration process of droplets flowing into the merging section; Fig. 4 is a graph showing a change in the average velocity UL in a deceleration process of droplets flowing into the merging section; Fig. 5 is a diagram showing a change in a spacing ratio Lmix / Lv when the Mach number Mtp of a refrigerant at the merging portion is changed; Fig. 6 is a schematic configuration diagram of an indoor air conditioning unit of the first embodiment; Fig. 7 is a block diagram showing an electronic control unit of the vehicle air conditioner of the first embodiment; Fig. 8 is a schematic overall configuration diagram illustrating a flow of refrigerant in a single hot gas air heating mode of a heat pump cycle in the first embodiment; Fig. 9 is a Mollier diagram showing a change in a state of the refrigerant in the single hot gas air heating mode of the heat pump cycle in the first embodiment; Fig. 10 is a schematic overall configuration diagram illustrating the flow of refrigerant in a single hot gas dehumidification and air heating mode of the heat pump cycle in the first embodiment; Fig. 11 is a Mollier diagram showing a change in the state of the refrigerant in the single hot gas dehumidification and air heating mode of the heat pump cycle in the first embodiment; Fig. 12 is a schematic overall configuration diagram illustrating a flow of refrigerant in a single hot gas series dehumidification and air heating mode of the heat pump cycle in the first embodiment; Fig. 13 is a Mollier diagram showing a change in a state of the refrigerant in the single hot gas series dehumidification and air heating mode of the heat pump cycle in the first embodiment; Fig. 14 is a schematic overall configuration diagram of a vehicle air conditioner of a second embodiment; Fig. 15 is a schematic overall configuration diagram of a vehicle air conditioner of a third embodiment; Fig. 16 is a schematic overall configuration diagram of a vehicle air conditioner of a fourth embodiment; and Fig. 17 is a schematic overall configuration diagram of a vehicle air conditioner of a fifth embodiment. DESCRIPTION OF THE EMBODIMENTS

[0020] A variety of embodiments for carrying out the present disclosure will be described below with reference to the drawings. In each embodiment, parts corresponding to those described in the previous embodiment are designated by the same reference numerals, and redundant description may be omitted. In a case where only a part of the configuration is described in each embodiment, other embodiments described above may be applied to other parts of the configuration. It is possible not only to combine parts that can be explicitly combined in the embodiments, but also to partially combine the embodiments even if not explicitly stated, if there are no problems in the combination. (First embodiment)

[0021] A first embodiment of a heat pump cycle device according to the present disclosure will be described with reference to Fig. 1 to 13. In the present embodiment, the heat pump cycle device according to the present disclosure is applied to a vehicle air conditioner 1 mounted on an electric vehicle. The electric vehicle is a vehicle that receives driving power for running from an electric motor. The vehicle air conditioner 1 performs air conditioning in a vehicle cabin, which is a space to be air-conditioned, and also controls the temperature of an on-vehicle device. Therefore, the vehicle air conditioner 1 can be referred to as an air conditioner with an on-vehicle device temperature control function or an on-vehicle device temperature control device with an air conditioning function.

[0022] Specifically, the vehicle air conditioner 1 regulates the temperature of a battery 70 as an on-vehicle device. The battery 70 is a secondary battery that stores electric power supplied to a plurality of on-vehicle devices powered by electricity. The battery 70 is a composite battery formed by electrically connecting a plurality of battery cells arranged in a stacked manner in series or parallel. The battery cell of the present embodiment is a lithium-ion battery.

[0023] The battery 70 generates heat during operation (i.e., during charging and discharging). The output of the battery 70 is likely to decrease at a low temperature, and the battery is likely to deteriorate at a high temperature. Therefore, the temperature of the battery 70 needs to be maintained within a suitable temperature range (in the present embodiment, equal to or higher than 15°C and equal to or lower than 55°C). Therefore, in the electric vehicle of the present embodiment, the temperature of the battery 70 is controlled using the vehicle air conditioner 1. Needless to say, the on-vehicle device whose temperature is to be controlled by the vehicle air conditioner 1 is not limited to the battery 70.

[0024] The vehicle air conditioner 1 includes a heat pump cycle 10, a high-temperature side heat medium circuit 30, a low-temperature side heat medium circuit 40, an indoor air conditioning unit 50, a control device 60, and the like.

[0025] First, the heat pump circuit 10 is described with reference to Fig. 1. The heat pump circuit 10 is a vapor compression refrigeration circuit that regulates the temperature of ventilation air supplied to the vehicle cabin, a high-temperature side heat medium circulating in the high-temperature side heat medium circuit 30, and a low-temperature side heat medium circulating in the low-temperature side heat medium circuit 40.

[0026] The heat pump cycle 10 is designed to be capable of switching a refrigerant circuit based on various operating modes, which will be described later, to perform air conditioning of the vehicle cabin and temperature control of the vehicle's onboard device. The heat pump cycle 10 uses an HFO refrigerant (specifically, R1234yf) as a refrigerant. The heat pump cycle 10 is designed as a subcritical refrigeration cycle in which the refrigerant pressure on a high-pressure side does not exceed the critical refrigerant pressure.

[0027] Refrigerant oil for lubricating a compressor 11 is mixed with the refrigerant. The refrigerant oil is a PAG oil (i.e., polyalkylene glycol oil) compatible with a liquid-phase refrigerant or POE (i.e., polyol ester). A portion of the refrigerant oil circulates in the heat pump circuit 10 along with the refrigerant.

[0028] Compressor 11 draws in, compresses, and discharges the refrigerant in heat pump cycle 10. Compressor 11 is an electric compressor in which a fixed-capacity compression mechanism with a fixed discharge capacity is rotationally driven by an electric motor. The refrigerant discharge capacity (i.e., the rotational speed) of compressor 11 is controlled by a control signal output from control device 60, which will be described later.

[0029] The compressor 11 is arranged in a drive unit chamber formed at the front of the vehicle cabin. The drive unit chamber forms a space in which at least a part of a device (e.g., a motor generator as an electric traction motor) used to generate or control driving force for vehicle travel is arranged.

[0030] An inlet port side of a first three-way joint 12a is connected to a discharge port of the compressor 11. The first three-way joint 12a has three inlet and outlet ports that communicate with each other. As the first three-way joint 12a, a joint formed by connecting a plurality of tubes or a joint formed by providing a plurality of refrigerant passages in a metal block or a resin block can be used.

[0031] As described later, the heat pump cycle 10 further includes second to sixth three-way junctions 12b to 12f. The basic configurations of the second to sixth three-way junctions 12b to 12f are similar to that of the first three-way junction 12a. The basic configuration of each three-way junction described in the embodiments to be described later is also similar to that of the first three-way junction 12a.

[0032] In these three-way junctions, if one of the three inlet and outlet ports is used as the inlet port and the remaining two as the outlet ports, the refrigerant flow is branched. If two of the three inlet and outlet ports are used as the inlet ports and the remaining port is used as the outlet port, the refrigerant flows are combined. The first three-way junction 12a is a branch section that branches the flow of the refrigerant discharged from the compressor 11.

[0033] An inlet port side of a refrigerant passage in a water-refrigerant heat exchanger 13 is connected to one outlet port of the first three-way junction 12a. An inlet port side of the sixth three-way junction 12f is connected to the other outlet port of the first three-way junction 12a.

[0034] The refrigerant passage from the other outlet port of the first three-way junction 12a to an inlet port of the sixth three-way junction 12f is a bypass passage 21c. A bypass-side flow rate control valve 14d is arranged in the bypass passage 21c.

[0035] The bypass-side flow rate control valve 14d is a bypass-passage-side decompression unit that decompresses the discharge refrigerant (that is, the other discharge refrigerant branched at the first three-way junction 12a) flowing out from the other outlet port of the first three-way junction 12a in a hot gas air heating mode or the like, which will be described later. The bypass-side flow rate control valve 14d is a bypass-side flow rate control unit that controls the flow rate (the mass flow rate) of the refrigerant flowing through the bypass passage 21c.

[0036] The bypass-side flow rate control valve 14d is an electric variable throttle mechanism including a valve body that changes the throttle opening and an electric actuator (specifically, a stepping motor) as a drive unit that adjusts the valve body. The operation of the bypass-side flow rate control valve 14d is controlled by a control pulse output from the control device 60.

[0037] The bypass-side flow rate control valve 14d has a full-opening function of functioning as a simple refrigerant passage without exhibiting a refrigerant decompression effect, and a flow rate control effect by setting the throttle opening in a fully open state. The bypass-side flow rate control valve 14d has a full-closing function of closing the refrigerant passage by setting the throttle opening in a fully closed state.

[0038] The heat pump cycle 10 further includes an air heating expansion valve 14a, an air cooling expansion valve 14b, and a cooling expansion valve 14c, as described later. The basic configurations of the air heating expansion valve 14a, the air cooling expansion valve 14b, and the cooling expansion valve 14c are similar to those of the bypass-side flow rate control valve 14d.

[0039] The air heating expansion valve 14a, the air cooling expansion valve 14b, the cooling expansion valve 14c, and the bypass-side flow rate control valve 14d can switch the refrigerant circuit by exhibiting the full-closing function. Therefore, the air heating expansion valve 14a, the air cooling expansion valve 14b, the cooling expansion valve 14c, and the bypass-side flow rate control valve 14d also function as a refrigerant circuit switching unit.

[0040] Needless to say, the air heating expansion valve 14a, the air cooling expansion valve 14b, the cooling expansion valve 14c, and the bypass-side flow rate control valve 14d may be configured by combining a variable throttle mechanism that does not have a full-closing function and an on / off valve that opens and closes a throttle passage. In this case, each on / off valve serves as a refrigerant circuit switching unit.

[0041] The water-to-refrigerant heat exchanger 13 is a heat-radiating heat exchange unit that exchanges heat between the high-pressure refrigerant discharged from the compressor 11 and the high-temperature-side heat medium circulating in the high-temperature-side heat medium circuit 30, transferring heat from the high-pressure refrigerant to the high-temperature-side heat medium. In the present embodiment, a so-called subcooling heat exchanger is used as the water-to-refrigerant heat exchanger 13. For this reason, a condensing section 13a, a receiver 13b, and a subcooling section 13c are arranged in the refrigerant passage of the water-to-refrigerant heat exchanger 13.

[0042] The condensing section 13a is a condensing heat exchange unit that exchanges heat between the high-pressure refrigerant discharged from the compressor 11 and the high-pressure side heat medium to condense the high-pressure refrigerant. The receiver 13b is a high-pressure side gas-liquid separation unit that separates the refrigerant flowing out of the condensing section 13a into gas and liquid and stores the separated liquid-phase refrigerant as excess refrigerant in the cycle. The subcooling section 13c is a subcooling heat exchange unit that exchanges heat between the liquid-phase refrigerant flowing out of the receiver 13b and the high-pressure side heat medium to subcool the liquid-phase refrigerant.

[0043] An inlet port side portion of the second three-way junction 12b is connected to an outlet port of the refrigerant passage in the water-refrigerant heat exchanger 13 (specifically, to an outlet port of the subcooling portion 13c). An inlet port side of the air-heating expansion valve 14a is connected to an outlet port of the second three-way junction 12b. An inlet port side of a four-way junction 12x is connected to the other outlet port of the second three-way junction 12b.

[0044] The refrigerant passage from the other outlet port of the second three-way joint 12b to an inlet port of the four-way joint 12x is a dehumidification passage 21a. An ON / OFF dehumidification valve 22a is arranged in the dehumidification passage 21a.

[0045] The dehumidification ON / OFF valve 22a is an ON / OFF valve that opens and closes the dehumidification passage 21a. The dehumidification ON / OFF valve 22a is an electromagnetic valve whose opening and closing operation is controlled by a control voltage output from the control device 60. The dehumidification ON / OFF valve 22a can switch the refrigerant circuit by opening and closing the dehumidification passage 21a. Therefore, the dehumidification ON / OFF valve 22a is a refrigerant circuit switching unit.

[0046] The four-way 12x joint is a joint with four interconnected inlet and outlet ports. A joint constructed similarly to the three-way joint can be used as the four-way 12x joint. A joint constructed by combining two three-way joints can be used as the four-way 12x joint.

[0047] The air-heating expansion valve 14a is a decompression unit on the outdoor heat exchanger side that decompresses the refrigerant flowing into the outdoor heat exchanger 15 in an air-heating mode or the like, which will be described later. The air-heating expansion valve 14a is also a flow rate control unit on the outdoor heat exchanger side that controls the flow rate (mass flow rate) of the refrigerant flowing into the outdoor heat exchanger 15.

[0048] A refrigerant inlet port side of the outdoor heat exchanger 15 is connected to an outlet port of the air-heating expansion valve 14a. The outdoor air heat exchanger 15 is an outdoor heat exchange unit that exchanges heat between the refrigerant flowing out of the air-heating expansion valve 14a and outside air supplied by an outside air fan (not shown). The outdoor heat exchanger 15 is arranged at the front side of the power unit chamber. This allows driving air flowing into the power unit chamber through a grille to be applied to the outdoor heat exchanger 15 during vehicle travel.

[0049] An inlet port side of the third three-way joint 12c is connected to a refrigerant outlet port of the outdoor heat exchanger. Another inlet port side of the four-way joint 12x is connected to an outlet port of the third three-way joint 12c via a first check valve 16a. An inlet port side of the fourth three-way joint 12d is connected to the other outlet port of the third three-way joint 12c.

[0050] The refrigerant passage from the other outlet port of the third three-way junction 12c to an inlet port of the fourth three-way junction 12d is an air heating passage 21b. An ON / OFF air heating valve 22b is arranged in the air heating passage 21b.

[0051] The on / off air heating valve 22b is an on / off valve that opens and closes the air heating passage 21b. The basic configuration of the on / off air heating valve 22b is similar to that of the on / off dehumidification valve 22a. Therefore, the on / off air heating valve 22b is a refrigerant cycle switching unit. The basic configuration of each on / off valve described in the embodiments described later is also the same as that of the on / off dehumidification valve 22a.

[0052] The first check valve 16a allows the refrigerant to flow from the third three-way joint 12c side to the four-way joint 12x side and prevents the refrigerant from flowing from the four-way joint 12x side to the third three-way joint 12c side.

[0053] A refrigerant inlet port side of an indoor evaporator 18 is connected to an outlet port of the four-way junction 12x via the air cooling expansion valve 14b.

[0054] The air-cooling expansion valve 14b is a decompression unit on the indoor evaporator side that decompresses the refrigerant flowing into the indoor evaporator 18 in an air-cooling mode, a hot-gas dehumidification and air-heating mode, or the like, which will be described later. Therefore, the air-cooling expansion valve 14b serves as a heating-unit-side decompression unit in the hot-gas dehumidification and air-heating mode or the like. The air-cooling expansion valve 14b is also a flow rate control unit on the indoor evaporator side that controls the flow rate (mass flow rate) of the refrigerant flowing into the indoor evaporator 18.

[0055] The interior evaporator 18 is arranged in an air conditioning case 51 of the interior air conditioning unit 50, which will be described later. The interior evaporator 18 is an air-cooling heat exchange unit that exchanges heat between the low-pressure refrigerant decompressed by the air-cooling expansion valve 14b and the ventilation air supplied toward the vehicle cabin by an interior fan 52. The interior evaporator 18 cools the ventilation air by evaporating the low-pressure refrigerant and exhibits a heat absorption effect.

[0056] An inlet port side of the fifth three-way junction 12e is connected to a refrigerant outlet port of the indoor evaporator 18 via a second check valve 16b. The second check valve 16b allows refrigerant to flow from the refrigerant outlet port side of the indoor evaporator 18 to the fifth three-way junction 12e side and prevents refrigerant from flowing from the fifth three-way junction 12e side to the refrigerant outlet port side of the indoor evaporator 18.

[0057] An inlet port side of a refrigerant passage in a radiator 20 is connected to another outlet port of the four-way junction 12x via the cooling expansion valve 14c.

[0058] The cooling expansion valve 14c is a cooler-side decompression unit that decompresses the refrigerant flowing into the cooler 20 in a cooling-and-air cooling mode, the hot-gas air heating mode, or the like, which will be described later. Therefore, the cooling expansion valve 14c serves as a heating-unit-side decompression unit in the hot-gas air heating mode or the like. The cooling expansion valve 14c is also a cooler-side flow rate control unit that controls the flow rate (mass flow rate) of the refrigerant flowing into the cooler 20.

[0059] The cooler 20 is a temperature-regulating heat exchange unit that exchanges heat between the low-pressure refrigerant decompressed by the cooling expansion valve 14c and the low-temperature side heat medium circulating in the low-temperature side heat medium circuit 40. The cooler 20 cools the low-temperature side heat medium by evaporating the low-pressure refrigerant and exhibits the heat absorption effect.

[0060] The other inlet port side of the fourth three-way junction 12d is connected to an outlet port of the refrigerant passage in the radiator 20. The other inlet port side of the fifth three-way junction 12e is connected to an outlet port of the fourth three-way junction 12d. The other inlet port side of the sixth three-way junction 12f is connected to an outlet port of the fifth three-way junction 12e. A suction port side of the compressor 11 is connected to an outlet port of the sixth three-way junction 12f.

[0061] Accordingly, in the hot gas air heating mode or the like, the sixth three-way junction 12f serves as a merging portion that merges the flow of the heating unit-side refrigerant flowing out of the heating unit-side decompression unit and the flow of the bypass-side refrigerant flowing out of the bypass-side flow rate control valve 14d and causes the merged flow to flow to the suction port side of the compressor 11.

[0062] As shown in the sectional view of Fig. 2, the refrigerant passage in the sixth three-way junction 12f of the present embodiment is formed in such a manner that the flow direction of the main flow of the heating unit-side refrigerant immediately before merging and the flow direction of the main flow of the bypass-side refrigerant immediately before merging intersect with each other. Specifically, the refrigerant passage in the sixth three-way junction 12f of the present embodiment is formed in such a manner that the merging angle θv, which is an angle formed by the flow direction of the main flow of the heating unit-side refrigerant and the flow direction of the main flow of the bypass-side refrigerant, is approximately 90°.

[0063] The refrigerant passage from the outlet port of the sixth three-way junction 12f to the suction port of the compressor 11 is a suction-side passage 21d, which forms a suction-side flow path. In the present embodiment, when the length of the suction-side passage 21d is defined as a suction-side flow path length L1, the suction-side flow path length L1 is equal to or longer than a relief distance Lv.

[0064] The suction-side flow path length L1 can be defined by the length of the center line of the tube forming the suction-side passage 21d. In a case where the suction-side passage 21d is curved, the length can be defined by the length of the center line connecting the centers (centers of gravity) in cross sections perpendicular to the refrigerant flow direction of the refrigerant tube forming the suction-side passage 21d.

[0065] The expansion distance Lv is a flow path length required to mix a relatively low-enthalpy two-phase gas-liquid refrigerant and a relatively high-enthalpy gas-phase refrigerant at the sixth three-way junction 12f, which is a merging section, and eliminate the non-equilibrium state of the mixed refrigerant. That is, the expansion distance Lv is a flow path length required to bring the refrigerant mixed at the merging section into a homogeneous state.

[0066] Here, the refrigerant in the homogeneous state can be defined as a refrigerant whose temperature and velocity have reached an equilibrium state and whose temperature distribution and velocity distribution have been sufficiently suppressed.

[0067] In a case where the homogeneous state of the refrigerant combined at the sixth three-way junction 12f is a two-phase gas-liquid refrigerant, the refrigerant can be defined as a refrigerant in which the droplets, which are particles of the liquid-phase refrigerant contained in the refrigerant, are uniformly distributed in the gas-phase refrigerant, and the temperature distribution and velocity distribution between the droplets and the gas-phase refrigerant are sufficiently suppressed.

[0068] The relaxation distance Lv is defined by the following formula F1. [Calculation 2] Lv=τv×Uv τv is a velocity relaxation time. Uv is the average flow velocity of the droplets and the gas-phase refrigerant at a junction point MX of the heating unit-side refrigerant and the bypass-side refrigerant in the sixth three-way junction 12f.

[0069] To determine the expansion distance Lv, it is necessary to examine the velocity equilibrium and temperature equilibrium between the droplets and the gas-phase refrigerant at the junction point MX. Even if the equilibrium state of the combined refrigerant is the gas-phase refrigerant, the droplets and the gas-phase refrigerant are located at the junction point MX.

[0070] First, the velocity equilibrium between the droplets and the gas-phase refrigerant will be investigated. The equation of motion for the drag force acting on the droplets at the junction point MX can be expressed by formula F2 using Stokes' drag equation. [Calculation 3] mdULdt3π×μg×dp(Ug−UL) m is the average droplet mass at the junction MX. UL is the average droplet velocity at the junction MX. Ug is the average velocity of the gas-phase refrigerant at the junction MX. µg is the viscosity of the gas-phase refrigerant at the junction MX. dp is the average droplet diameter at the junction MX.

[0071] Furthermore, as shown in Formula 3, the velocity relaxation time τv is defined. [Calculation 4] τv=m3π×μg×dp

[0072] Consequently, formula F2 can be transformed as shown in formula F4. [Calculation 5] dULdt=Ug−ULτv

[0073] Since the average velocity UL of the droplets and the average velocity Ug of the gas-phase refrigerant eventually converge to the same value, the velocity relaxation time τv in the above formula F3 is a parameter representing the followability with respect to the fluid motion of the droplets. Solving the above formula F4 with the average velocity Ug as a constant value and the average velocity of the droplets at time t=0 as a constant value UL0, the time required for the average velocity UL of the droplets to relax to the average velocity Ug of the gas-phase refrigerant can be calculated.

[0074] As in the Fig. 3 and Fig. As shown in Figure 4, it has been confirmed that the time required for the average droplet velocity UL to reach the average velocity Ug of the gas-phase refrigerant decreases with decreasing velocity relaxation time τv in both the acceleration and deceleration processes of the droplets. Furthermore, it has been confirmed that with decreasing velocity relaxation time τv, the time when the average droplet velocity UL reaches the average velocity Ug of the gas-phase refrigerant actually approaches.

[0075] By expressing the average mass m of the droplets at the junction MX in terms of the average droplet diameter dp at the junction MX, formula F3 can be reformulated as shown in formula F5. [Calculation 6] τv=ρL×πdp36×13π×μg×dp=ρL×dp218μg ρL is the density of the droplets at the junction MX.

[0076] As can be seen from Formula F5, the velocity relaxation time τv is proportional to the number obtained by squaring the average droplet diameter dp at the junction MX. The velocity relaxation time τv is inversely proportional to the viscosity µg of the gas-phase refrigerant at the junction MX. Therefore, the velocity relaxation time τv decreases with decreasing average droplet diameter dp at the junction MX.

[0077] According to the present inventors' study, it was found that the measured value of the average droplet diameter dp at the junction MX of the heat pump cycle device of the present embodiment is approximately 3 to 5 µm. Since the velocity relaxation time τv is a relatively small value, the velocity relaxation time can therefore be used as the time when the average velocity UL of the droplets reaches the average velocity Ug of the gas-phase refrigerant.

[0078] Next, the temperature equilibrium between the droplets and the gas-phase refrigerant is investigated. For temperature equilibrium, it is necessary to investigate both the gas-side heat transfer quantity Qg from the droplet interface to the gas-phase refrigerant and the droplet-side heat transfer quantity QL from the droplet interface to the interior of the droplet for each droplet. The gas-side heat transfer quantity Qg can be expressed by Formula F6 from the Newtonian cooling measurement. [Calculation 7] Q˙g=∂∂thtg(Tsu−Tsg)×π×dp2 htg is the heat transfer coefficient of the gas-phase refrigerant. Tsu is the average refrigerant temperature at the droplet interface. Tsg is the average refrigerant temperature of the gas-phase refrigerant.

[0079] In addition, the gas-side temperature relaxation time τtg corresponding to the velocity relaxation time τv is defined, and the formula F6 is converted as shown in formula F7. [Calculation 8] dTsgdt=Tsu−Tsgτtg

[0080] Similar to the velocity relaxation time τv, the gas-side temperature relaxation time τtg can be expressed by formula F8 when formula F7 is solved. [Calculation 9] τtg=ρg×Cpg×dp6htg ρg is the density of the gas-phase refrigerant at the junction MX. Cpg is the specific low-pressure heat of the gas-phase refrigerant.

[0081] Similarly, the droplet-side heat transfer quantity QL can be expressed by the formula F9 from the Newtonian cooling measurement. [Calculation 10] Q˙L=∂∂thtL(Tsu−TsL)×π×dp2 htL is the heat transfer coefficient of the droplets. TsL is the average refrigerant temperature in the droplets.

[0082] In addition, the droplet-side temperature relaxation time τtL, which corresponds to the velocity relaxation time τv, is defined, and the formula F9 is transformed as shown in formula F10. [Calculation 11] dTsLdt=Tsu−TsLτtL

[0083] Similar to the velocity relaxation time τv, the droplet-side temperature relaxation time τtL can be expressed by formula F11 when the above formula F10 is solved. [Calculation 12] τtL=ρL×CpL×dp6htL CpL is the specific low-pressure heat of the droplets.

[0084] Here, the ratio of the gas-side temperature relaxation time τtg to the velocity relaxation time τv can be expressed by Formula F13 using the Prandtl number Prg of the gas-phase refrigerant, which is expressed by Formula F12. Similarly, the ratio of the droplet-side temperature relaxation time τtL to the velocity relaxation time τv can be expressed by Formula F14 using the Prandtl number Prg. The Prandtl number is a dimensionless quantity that represents the relationship between the kinematic viscosity coefficient and the thermal diffusion coefficient of a fluid. [Calculation 13] Prg=μgCpgλtg λtg is the specific low-pressure heat of the gas-phase refrigerant. [Calculation 14] τTgτv=3PrgNugρgρL

[0085] Nug is the Nusselt number of the gas-phase refrigerant. The Nusselt number is a dimensionless quantity that indicates the ratio of heat conduction in a stationary fluid to heat transfer by convection. [Calculation 15] τTLτv=3PrgNuLCpLCpgλtgλtL

[0086] NuL is the Nusselt number of the droplets. λtL is the specific low-pressure heat of the droplets.

[0087] According to formulas F13 and F14, the ratio of the gas-side temperature relaxation time τtg to the velocity relaxation time τv and the ratio of the gas-side temperature relaxation time τtg to the droplet-side temperature relaxation time τtL are determined by the state variables of the two-phase gas-liquid refrigerant at the junction point MX. In other words, the ratio of the gas-side temperature relaxation time τtg to the velocity relaxation time τv and the ratio of the gas-side temperature relaxation time τtg to the droplet-side temperature relaxation time τtL are generally determined by the operating environment and the physical properties of the refrigerant.

[0088] Therefore, the present inventors investigated the ratio of the gas-side temperature relaxation time τtg to the velocity relaxation time τv and the ratio of the gas-side temperature relaxation time τtg to the droplet-side temperature relaxation time τtL under the use conditions of the heat pump cycle device of the present embodiment. As a result, it was found that the measured values ​​of the ratio of the gas-side temperature relaxation time τtg to the velocity relaxation time τv and the ratio of the gas-side temperature relaxation time τtg to the droplet-side temperature relaxation time τtL are equal to or less than approximately 0.01.

[0089] That is, it was found that the temperature equilibrium state is reliably reached when the velocity relaxation time τv, which is the time when the droplets and the gas-phase refrigerant reach the velocity equilibrium state, has elapsed. As a result, in the present embodiment, the relaxation distance Lv is defined as a value obtained by multiplying the average flow velocity Uv of the refrigerant at the junction MX by the velocity relaxation time τv, as shown in Formula F1. Furthermore, the relaxation distance Lv can be defined by Formula F15 using Formula F1 and Formula F5. [Calculation 16] Lv=ρL×dp218μg×Uv

[0090] As can be seen from Formula F15, the expansion distance Lv is proportional to the value obtained by squaring the average droplet diameter dp at the junction MX, similar to the velocity expansion time τv. The expansion distance Lv is proportional to the average flow velocity Uv. The expansion distance Lv is inversely proportional to the viscosity µg of the gas-phase refrigerant at the junction MX.

[0091] Furthermore, the present inventors have confirmed the relationship between the expansion distance Lv and a required distance Lmix. The required distance Lmix is ​​the measured value of the distance required for the refrigerant that actually joins at the joining point MX of the sixth three-way junction 12f to be in a homogeneous state. As shown in Fig. As shown in Figure 5, the change in the spacing ratio (Lmix / Lv) between the required spacing Lmix and the relaxation spacing Lv was specifically investigated when the Mach number Mtp is changed. The Mach number Mtp is the ratio between the average flow velocity Uv and the speed of sound Us of the two-phase gas-liquid refrigerant.

[0092] The relationship between the expansion distance Lv and the required distance Lmix is ​​confirmed in the range where the dryness RxL of the heating unit-side refrigerant flowing into the junction MX is equal to or greater than 0.1 and equal to or less than 0.9. Furthermore, the relationship is confirmed in the range where the superheat degree of the bypass-side refrigerant flowing into the junction MX is equal to or greater than 0.3 K and equal to or less than 30 K. Furthermore, the relationship is confirmed in the range where the refrigerant pressure at the junction MX is equal to or greater than 0.08 MPa and equal to or less than 0.77 MPa.

[0093] As a consequence, as in Fig. 5, it is confirmed that the spacing ratio (Lmix / Lv) is approximately 1 regardless of the Mach number Mtp. That is, it is confirmed that the expansion distance Lv is substantially consistent with the required distance Lmix under a wide range of operating conditions. Therefore, the expansion distance Lv can be used as the flow path length required to mix the refrigerants combined at the sixth three-way junction 12f to be in a homogeneous state.

[0094] Furthermore, in the present embodiment, not only is the suction-side flow path length L1 set equal to or greater than the expansion distance Lv, but the suction-side flow path length L1 is also not unnecessarily increased to prevent an increase in the size of the heat pump cycle 10. For this reason, the actual suction-side flow path length L1 is equal to or less than 50 cm.

[0095] The following describes the Fig. 1 will be described. The high-temperature-side heat medium circuit 30 is a heat medium circuit that circulates a high-temperature-side heat medium. In the present embodiment, an aqueous ethylene glycol solution is used as the high-temperature-side heat medium. The high-temperature-side heat medium circuit 30 includes a heat medium passage of the water-refrigerant heat exchanger 13, a high-temperature-side pump 31, a heater core 32, and the like.

[0096] The high-temperature-side pump 31 is a high-temperature-side heat medium pumping unit that pumps the high-temperature-side heat medium flowing out of the heat medium passage of the water-refrigerant heat exchanger 13 to the heat medium inlet port side of the heater core 32. The high-temperature-side pump 31 is an electric pump whose rotational speed (ie, pumping power) is controlled by a control voltage output from the control device 60.

[0097] The heater core 32 is a heating heat exchanger that exchanges heat between the high-temperature side heat medium heated by the water-refrigerant heat exchanger 13 and the ventilation air flowing through the indoor evaporator 18 to heat the ventilation air. The heater core 32 is arranged in the air conditioning case 51 of the indoor air conditioning unit 50. An inlet port side of the heat medium passage in the water-refrigerant heat exchanger 13 is connected to a heat medium outlet port of the heater core 32.

[0098] Therefore, the constituent devices of the water-refrigerant heat exchanger 13 and the high-temperature side heat medium circuit 30 of the present embodiment are heating units that heat ventilation air as a heating object using a refrigerant branched at the first three-way junction 12a as a heat source.

[0099] Next, the low-temperature side heat medium circuit 40 will be described. The low-temperature side heat medium circuit 40 is a heat medium circuit that circulates a low-temperature side heat medium. In the present embodiment, the same type of fluid as the high-temperature side heat medium is used as the low-temperature side heat medium. In the low-temperature side heat medium circuit 40, a low-temperature side pump 41, a cooling water passage 70a of the battery 70, a heat medium passage of the radiator 20, and the like are connected.

[0100] The low-temperature side pump 41 is a low-temperature side heat medium pumping unit that pumps the low-temperature side heat medium flowing out of the cooling water passage 70a of the battery 70 to the inlet port side of the heat medium passage in the radiator 20. The basic configuration of the low-temperature side pump 41 is similar to that of the high-temperature side pump 31. An inlet port side of the cooling water passage 70a in the battery 70 is connected to an outlet port side of the heat medium passage in the radiator 20.

[0101] The cooling water passage 70a of the battery 70 is a cooling water passage configured to cool the battery 70 by circulating the low-temperature side heat medium cooled by the radiator 20. The cooling water passage 70a is formed inside a dedicated battery case that houses a plurality of battery cells arranged in a stacked manner.

[0102] The cooling water passage 70a has a passage configuration in which a plurality of passages are connected in parallel inside the dedicated battery case. This allows the cooling water passage 70a to cool all battery cells evenly. A suction port side of the low-temperature side pump 41 is connected to an outlet port of the cooling water passage 70a.

[0103] Next, the indoor air conditioning unit 50 will be described with reference to Fig. 6. The interior air conditioning unit 50 is a unit in which a plurality of constituent devices are integrated for blowing ventilation air, controlled to a suitable temperature for air conditioning the vehicle cabin, to a suitable location in the vehicle cabin. The interior air conditioning unit 50 is arranged within a dashboard (i.e., an instrument panel) in the frontmost part of the vehicle cabin.

[0104] The indoor air conditioning unit 50 is constructed by accommodating the indoor blower 52, the indoor evaporator 18, the heater core 32, and the like in the air conditioning case 51, which forms a passage for ventilation air. The air conditioning case 51 is formed of resin (e.g., polypropylene) that has a certain degree of elasticity and excellent strength.

[0105] An inside / outside air switching device 53 is arranged on the most upstream side of the air conditioning case 51 in a ventilation air flow. The inside / outside air switching device 53 switches inside air (i.e., air inside the vehicle cabin) and outside air (i.e., air outside the vehicle cabin) and introduces the air into the air conditioning case 51. The operation of the inside / outside air switching device 53 is controlled by a control signal output from the control device 60.

[0106] The interior fan 52 is arranged on the downstream side of the inside / outside air switching device 53 in the ventilation air flow. The interior fan 52 is a ventilation unit that supplies air drawn through the inside / outside air switching device 53 to the vehicle cabin. The rotational speed (ie, the ventilation power) of the interior fan 52 is controlled by a control voltage output from the control device 60.

[0107] The indoor evaporator 18 and the heater core 32 are arranged on the downstream side of the indoor fan 52 in the ventilation air flow. The indoor evaporator 18 is arranged on the upstream side of the heater core 32 in the ventilation air flow. A cold air bypass passage 55 is formed in the air conditioning case 51, in which the ventilation air flows after passing through the indoor evaporator 18, bypassing the heater core 32.

[0108] An air mixing door 54 is arranged on the downstream side of the indoor evaporator 18 in the ventilation air flow and on the upstream side of the heater core 32 and the cold air bypass passage 55 in the air conditioning case 51.

[0109] The air mix door 54 regulates an air volume ratio between the volume of ventilation air passing through the heater core 32 side and the volume of ventilation air passing through the cold air bypass passage 55 in the ventilation air after passing through the indoor evaporator 18. The operation of an actuator for driving the air mix door 54 is controlled by a control signal output from the control device 60.

[0110] A mixing space 56 is arranged on the downstream side of the heater core 32 and the cold air bypass passage 55 in the ventilation air flow. The mixing space 56 is a space for mixing the ventilation air heated by the heater core 32 and the ventilation air that passes through the cold air bypass passage 55 and has not been heated.

[0111] Therefore, in the interior air conditioning unit 50, the temperature of the ventilation air (ie, the conditioned air) mixed in the mixing chamber 56 and blown into the vehicle cabin can be controlled by regulating the opening of the air mixing door 54. The air mixing door 54 of the present embodiment is an air flow rate control unit that controls the flow rate of the ventilation air subjected to heat exchange in the heater core 32.

[0112] In a portion of the air conditioning case 51 on the downstream side of the ventilation air flow, a plurality of opening holes (not shown) are formed for blowing conditioned air to various locations in the vehicle cabin. A blow-mode door (not shown) that opens and closes each opening hole is disposed in each of the plurality of opening holes. The operation of an actuator for driving the blow-mode door is controlled by a control signal output from the control device 60.

[0113] Therefore, in the interior air conditioning unit 50, the conditioned air controlled to an appropriate temperature can be blown to an appropriate location in the vehicle cabin by switching the opening holes in which the blow mode door opens and closes.

[0114] Next, an electronic control unit of the present embodiment will be described. The control device 60 includes a known microcomputer including a CPU, a ROM, a RAM, and the like, as well as peripheral circuits thereof. The control device 60 performs various calculations and processing based on a control program stored in the ROM. The control device 60 then controls the operations of the various control target devices 11, 14a to 14d, 22a, 22b, 31, 41, 52, 53, and the like connected to the output side based on the calculation and processing results.

[0115] As shown in the block diagram of Fig. 7, a control sensor group including an inside air temperature sensor 61a, an outside air temperature sensor 61b, a solar radiation sensor 61c, a discharge refrigerant temperature sensor 62a, a high-pressure side refrigerant temperature-pressure sensor 62b, an outdoor device-side refrigerant temperature-pressure sensor 62c, an evaporator temperature sensor 62d, a radiator-side refrigerant temperature-pressure sensor 62e, a suction refrigerant temperature sensor 62f, a high-temperature side heat medium temperature sensor 63a, a low-temperature side heat medium temperature sensor 63b, a battery temperature sensor 64, an air-conditioning air temperature sensor 65, and the like is connected to the input side of the control device 60.

[0116] The inside air temperature sensor 61a is an inside air temperature detection unit that detects a vehicle cabin temperature (inside air temperature) Tr. The outside air temperature sensor 61b is an outside air temperature detection unit that detects a temperature outside the vehicle cabin (outside air temperature) Tam. The solar radiation sensor 61c is an solar radiation amount detection unit that detects an amount of solar radiation As irradiating the vehicle cabin.

[0117] The discharge refrigerant temperature sensor 62a is a discharge refrigerant temperature detecting unit that detects a discharge refrigerant temperature Td of the refrigerant discharged from the compressor 11.

[0118] The evaporator-side temperature sensor 62d is an evaporator temperature detection unit that detects a refrigerant evaporation temperature (evaporator temperature) Tefin in the indoor evaporator 18. Specifically, the evaporator temperature sensor 62d detects a heat exchange fin temperature of the indoor evaporator 18.

[0119] The high-pressure refrigerant temperature-pressure sensor 62b is a high-pressure-side refrigerant temperature-pressure detection unit that detects a high-pressure-side refrigerant temperature T1, which is the temperature of the refrigerant flowing out of the water-refrigerant heat exchanger 13, and a discharge refrigerant pressure Pd, which is the pressure of the refrigerant flowing out of the water-refrigerant heat exchanger 13. The discharge refrigerant pressure Pd can be used as the pressure of the refrigerant discharged from the compressor 11.

[0120] The outdoor device-side refrigerant temperature-pressure sensor 62c is an outdoor device-side refrigerant temperature-pressure detection unit that detects an outdoor device-side refrigerant temperature T2, which is the temperature of the refrigerant flowing out of the outdoor heat exchanger 15, and an outdoor device-side refrigerant pressure P2, which is the pressure of the refrigerant flowing out of the outdoor heat exchanger 15. Specifically, the temperature and pressure of the refrigerant flowing through the refrigerant passage from the refrigerant outlet port of the outdoor heat exchanger 15 to an inlet port of the third three-way junction 12c are detected.

[0121] The radiator-side refrigerant temperature-pressure sensor 62e is a radiator-side refrigerant temperature-pressure detection unit that detects a radiator-side refrigerant temperature Tc, which is the temperature of the refrigerant flowing out of the refrigerant passage of the radiator 20, and a radiator-side refrigerant pressure Pc, which is the pressure of the refrigerant flowing out of the refrigerant passage of the radiator 20. The radiator-side refrigerant pressure Pc can be used as a suction refrigerant pressure Ps, which is the pressure of the suction refrigerant drawn into the compressor 11. Therefore, the radiator-side refrigerant temperature-pressure sensor 62e of the present embodiment is a suction pressure detection unit.

[0122] In the present embodiment, a detection unit in which a pressure detection unit and a temperature detection unit are integrated is used as the refrigerant temperature-pressure sensor, but needless to say, a pressure detection unit and a temperature detection unit configured as separate units may be used.

[0123] The suction refrigerant temperature sensor 62f is a suction refrigerant temperature detection unit arranged in the suction-side passage 21d and detects a suction refrigerant temperature Ts, which is the temperature of the suction refrigerant sucked into the compressor 11. Furthermore, in the present embodiment, as shown in Fig. 1, when the length of the flow path from the outlet port of the sixth three-way junction 12f to the mounting portion of the suction refrigerant temperature sensor 62f in the suction side passage 21d is defined as the detection unit flow path length L2, the detection unit flow path length L2 is equal to or longer than the relaxation distance Lv.

[0124] Similar to the suction-side flow path length L1, the detection unit flow path length L2 can be defined by the length of the center line of a portion from the outlet port of the sixth three-way junction 12f to the mounting portion of the suction refrigerant temperature sensor 62f in the pipe forming the suction-side passage 21d.

[0125] The high-temperature-side heat medium temperature sensor 63a is a high-temperature-side heat medium temperature detection unit that detects a high-temperature-side heat medium temperature TWH, which is the temperature of the high-temperature-side heat medium flowing into the heater core 32. The low-temperature-side heat medium temperature sensor 63b is a low-temperature-side heat medium temperature detection unit that detects a low-temperature-side heat medium temperature TWL, which is the temperature of the low-temperature-side heat medium flowing into the cooling water passage 70a of the battery 70.

[0126] The battery temperature sensor 64 is a battery temperature detection unit that detects a battery temperature TB, which is the temperature of the battery 70. The battery temperature sensor 64 includes a plurality of temperature sensors and detects temperatures at a plurality of portions of the battery 70. Therefore, the control device 60 can detect a temperature difference between the individual battery cells constituting the battery 70 and their temperature distribution. Furthermore, the average value of the detection values ​​of the plurality of temperature sensors is used as the battery temperature TB.

[0127] The air conditioning air temperature sensor 65 is an air conditioning air temperature detection unit that detects a ventilation air temperature TAV of the ventilation air supplied from the mixing chamber 56 into the vehicle cabin. The ventilation air temperature TAV is an object temperature of the ventilation air as a heating object.

[0128] In addition, as in Fig. As shown in Figure 7, an operation panel 69, located near the instrument panel at the front of the vehicle cabin, is connected to the input side of the control device 60 in a wired or wireless manner. Operation signals from various operation switches provided on the operation panel 69 are input to the control device 60.

[0129] Specific examples of the various operation switches provided on the operation panel 69 include an automatic switch, an air conditioning switch, an air volume setting switch, and a temperature setting switch.

[0130] The automatic switch is an automatic control setting unit that sets or cancels the automatic control operation of the vehicle air conditioner 1. The air conditioner switch is a cooling request unit that requests the interior evaporator 18 to cool the ventilation air. The air volume setting switch is an air volume setting unit that manually sets the air volume of the interior blower 52. The temperature setting switch is a temperature setting unit that sets a setting temperature Tset in the vehicle cabin.

[0131] The control device 60 of the present embodiment is configured integrally with a control unit that controls various control target devices connected to the output side of the control device. Therefore, the configuration (ie, hardware and software) that controls the operation of each control target device constitutes the control unit that controls the operation of each control target device.

[0132] The configuration in the control device 60 that controls the refrigerant discharge capacity of the compressor 11 constitutes, for example, a discharge capacity control unit 60a. The configuration for controlling the operation of the heating-unit-side decompression unit (in the present embodiment, the air heating expansion valve 14a and the air cooling expansion valve 14b, as well as the cooling expansion valve 14c) constitutes a heating-unit-side control unit 60b. The configuration for controlling the operation of the bypass-side flow rate control valve 14d constitutes a bypass-side control unit 60c.

[0133] 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, various operating modes are switched to perform air conditioning in the vehicle cabin and temperature control of the battery 70. These operating modes are switched by executing a control program stored in advance in the control device 60. The various operating modes are described below.

[0134] First, an operation mode in which the refrigerant does not flow through the bypass passage 21c will be described. Examples of the operation mode in which the refrigerant does not flow through the bypass passage 21c include (a) an air cooling mode, (b) a series dehumidification and air heating mode, and (c) an outside air heat absorption and air heating mode. (a) Air cooling mode

[0135] The air cooling mode is an operating mode in which the air in the vehicle cabin is cooled by blowing cooled ventilation air into the vehicle cabin. In the control program, the air cooling mode is selected primarily in summer when the outside air temperature Tam is relatively high (25°C or higher in this embodiment).

[0136] The air cooling mode includes a single air cooling mode and a cooling and air cooling mode. The single air cooling mode is an operating mode in which the air in the vehicle cabin is cooled without cooling the battery 70. The cooling and air cooling mode is an operating mode in which the battery 70 is cooled and the air in the vehicle cabin is cooled simultaneously.

[0137] In the control program of the present embodiment, the operation mode of cooling the battery 70 is performed when the battery temperature TB detected by the battery temperature sensor 64 is equal to or higher than a predetermined upper reference limit temperature KTBH. The same applies to other operation modes described below. (a-1) Single air cooling mode

[0138] In the heat pump cycle 10 in the single-air cooling mode, the control device 60 brings the air heating expansion valve 14a to a fully open state, brings the air heating expansion valve 14b to a throttled state in which the refrigerant decompression effect is exhibited, brings the cooling expansion valve 14c to a fully closed state, and brings the bypass-side flow rate control valve 14d to a fully closed state. Furthermore, the control device 60 closes the dehumidification on / off valve 22a and also closes the air heating on / off valve 22b.

[0139] Therefore, in the heat pump cycle 10 in the single air cooling mode, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates in this order through the water-refrigerant heat exchanger 13, the air heating expansion valve 14a in the fully open state, the outdoor heat exchanger 15, the air cooling expansion valve 14b in the throttled state, the indoor evaporator 18, the suction side passage 21d and the suction port of the compressor 11.

[0140] The control device 60 controls the refrigerant discharge capacity of the compressor 11 such that the evaporator temperature Tefin detected by the evaporator temperature sensor 62d approaches a target evaporator temperature TEO. The target evaporator temperature TEO is determined based on a target blowing temperature TAO with reference to a control map stored in advance in the control device 60.

[0141] The target blowing temperature TAO is a target temperature of the ventilation air to be blown into the vehicle cabin. The target blowing temperature TAO is calculated using the inside air temperature Tr detected by the inside air temperature sensor 61a, the outside air temperature Tam, the amount of solar radiation As detected by the solar radiation sensor 61c, the setting temperature Tset set by the temperature setting switch, and the like. The control map specifies that the target evaporator temperature TEO increases as the target blowing temperature TAO increases.

[0142] The control device 60 controls the throttle opening of the air-cooling expansion valve 14b such that the superheat degree SH of the intake refrigerant approaches a predetermined reference superheat degree KSH (5°C in the present embodiment). The superheat degree SH of the intake refrigerant can be determined using the radiator-side refrigerant pressure Pc detected by the radiator-side refrigerant temperature-pressure sensor 62e and the intake refrigerant temperature Ts detected by the intake refrigerant temperature sensor 62f.

[0143] In the high-temperature-side heat medium circuit 30 in the single-air cooling mode, the control device 60 operates the high-temperature-side pump 31 to exhibit the predetermined reference pumping power. Therefore, in the high-temperature-side heat medium circuit 30 in the single-air cooling mode, the heat medium pumped by the high-temperature-side pump 31 circulates through the heat medium passage of the water-refrigerant heat exchanger 13, the heater core 32, and the suction port of the high-temperature-side pump 31 in this order.

[0144] Furthermore, in the indoor air conditioning unit 50 in the single-air cooling mode, the control device 60 controls the ventilation power of the indoor fan 52 based on the target blowing temperature TAO with reference to the control map prestored in the control device 60. The control device 60 controls the opening of the air mixing door 54 so that the ventilation air temperature TAV detected by the air conditioning air temperature sensor 65 approaches the target blowing temperature TAO. The control device 60 appropriately controls the operation of other control target devices.

[0145] Therefore, in the heat pump cycle 10 in the single air cooling mode, a vapor compression refrigeration cycle is designed in which the water-refrigerant heat exchanger 13 and the outdoor heat exchanger 15 function as condensers, radiate the heat of the refrigerant and condense the refrigerant, and the indoor evaporator 18 functions as an evaporator that evaporates the refrigerant.

[0146] In the high-temperature side heat medium circuit 30 in the single-air cooling mode, the high-temperature side heat medium heated by the water-refrigerant heat exchanger 13 flows into the heater core 32.

[0147] In the interior air conditioning unit 50 in the single-air cooling mode, the ventilation air supplied by the interior blower 52 is cooled by the interior evaporator 18. The ventilation air cooled by the interior evaporator 18 is reheated by the heater core 32 to approach the target blowing temperature TAO based on the opening of the air mixing door 54. The ventilation air at a controlled temperature is blown into the vehicle cabin, so that the air in the vehicle cabin is cooled. (a-2) Cooling and air cooling mode

[0148] In the heat pump cycle 10 in the cooling and air cooling mode, the control device 60 brings the cooling expansion valve 14c into the throttled state compared to the single air cooling mode.

[0149] Therefore, in the heat pump cycle 10, in the cooling-and-air-cooling mode, the refrigerant discharged from the compressor 11 circulates similarly to the single-air-cooling mode. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the water-refrigerant heat exchanger 13, the air-heating expansion valve 14a in the fully open state, the outdoor heat exchanger 15, the cooling expansion valve 14c in the throttled state, the chiller 20, the suction-side passage 21d, and the suction port of the compressor 11 in this order. That is, the refrigerant circuit is switched to a refrigerant circuit in which the indoor evaporator 18 and the chiller 20 are connected in parallel with the refrigerant flow.

[0150] The control device 60 controls the throttle opening of the cooling expansion valve 14c to a predetermined throttle opening for the cooling and air cooling mode.

[0151] In the high-temperature side heat medium circuit 30 in the cooling and air-cooling mode, the control device 60 operates the high-temperature side pump 31 as in the single air-cooling mode.

[0152] In the low-temperature side heat medium circuit 40 in the cooling and air-cooling mode, the control device 60 operates the low-temperature side pump 41 to exhibit the predetermined reference pumping power. Therefore, in the low-temperature side heat medium circuit 40 in the single-air-cooling mode, the heat medium pumped by the low-temperature side pump 41 circulates through the heat medium passage of the radiator 20, the cooling water passage 70a of the battery 70, and the suction port of the low-temperature side pump 41 in this order.

[0153] In the indoor air conditioning unit 50 in the cooling and air cooling mode, the control device 60 controls the ventilation power of the indoor fan 52 and the opening of the air mixing door 54 as in the single air cooling mode. In addition, the control device 60 appropriately controls the operations of other control target devices as in the single air cooling mode.

[0154] Therefore, in the heat pump cycle 10 in the cooling and air cooling mode, a vapor compression refrigeration cycle is designed in which the water-refrigerant heat exchanger 13 and the outdoor heat exchanger 15 function as condensers and the indoor evaporator 18 and the cooler 20 function as evaporators.

[0155] In the high-temperature side heat medium circuit 30 in the cooling and air cooling mode, the high-temperature side heat medium heated by the water-refrigerant heat exchanger 13 flows into the heater core 32 as in the single air cooling mode.

[0156] In the low-temperature side heat medium circuit 40, in the cooling and air-cooling mode, the low-temperature side heat medium pumped by the low-temperature side pump 41 flows into the radiator 20. The low-temperature side heat medium flowing into the radiator 20 exchanges heat with the low-pressure refrigerant and is cooled. The low-temperature side heat medium cooled by the radiator 20 flows through the cooling water passage 70a of the battery 70. As a result, the battery 70 is cooled.

[0157] In the interior air conditioning unit 50, in the cooling and air cooling mode, the ventilation air is blown into the vehicle cabin at a controlled temperature so that the air in the vehicle cabin is cooled, as in the single air cooling mode. (b) Series dehumidification and air heating mode

[0158] The series dehumidification and air heating mode is an operating mode in which the air in the vehicle cabin is dehumidified and heated by reheating cooled and dehumidified ventilation air and blowing the reheated ventilation air into the vehicle cabin. In the control program, the series dehumidification and air heating mode is selected when the outside air temperature Tam is within a predetermined medium to high temperature range (equal to or higher than 10°C and lower than 25°C in the present embodiment).

[0159] Examples of the row dehumidification and air heating mode include a single-row dehumidification and air heating mode and a cooling-row dehumidification and air heating mode. The single-row dehumidification and air heating mode is an operating mode in which the air in the vehicle cabin is dehumidified and heated without cooling the battery 70. The cooling-row dehumidification and air heating mode is an operating mode in which the battery 70 is cooled while simultaneously dehumidifying and heating the air in the vehicle cabin. (b-1) Single-row dehumidification and air heating mode

[0160] In the heat pump cycle 10 in the single-row dehumidification and air heating mode, the control device 60 places the air heating expansion valve 14a in the throttled state, the air cooling expansion valve 14b in the throttled state, the cooling expansion valve 14c in the fully closed state, and the bypass-side flow rate control valve 14d in the fully closed state. Furthermore, the control device 60 closes the dehumidification on / off valve 22a and also closes the air heating on / off valve 22b.

[0161] Therefore, in the heat pump cycle 10 in the single-row dehumidification and air heating mode, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the water-refrigerant heat exchanger 13, the air heating expansion valve 14a in the throttled state, the outdoor heat exchanger 15, the air cooling expansion valve 14b in the throttled state, the indoor evaporator 18, the suction side passage 21d, and the suction port of the compressor 11 in this order.

[0162] Furthermore, the control device 60 controls the throttle opening of the air-heating expansion valve 14a and the throttle opening of the air-cooling expansion valve 14b with reference to the control map stored in advance in the control device 60. In the control map, the throttle opening of the air-heating expansion valve 14a and the throttle opening of the air-cooling expansion valve 14b are determined in such a way that the superheat degree SH of the intake refrigerant approaches the reference superheat degree KSH.

[0163] In the high-temperature side heat medium circuit 30 in the single-row dehumidification and air heating mode, the control device 60 operates the high-temperature side pump 31 as in the single-air cooling mode.

[0164] In the indoor air conditioning unit 50 in the single-row dehumidification and air heating mode, the control device 60 controls the ventilation power of the indoor fan 52 and the opening of the air mixing door 54 as in the single-air cooling mode. The control device 60 appropriately controls the operations of the other control target devices.

[0165] Therefore, in the heat pump cycle 10 in the single-row dehumidification and air heating mode, a vapor compression refrigeration cycle is designed in which the water-refrigerant heat exchanger 13 functions as a condenser and the indoor evaporator 18 functions as an evaporator.

[0166] In the single-row dehumidification and air heating mode, the outdoor heat exchanger 15 also functions as a condenser in a case where the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is higher than the outside air temperature Tam. In a case where the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is lower than the outside air temperature Tam, the outdoor heat exchanger 15 functions as an evaporator.

[0167] In the high-temperature side heat medium circuit 30 in the single-row dehumidification and air heating mode, the high-temperature side heat medium heated by the water-refrigerant heat exchanger 13 flows into the heater core 32.

[0168] In the indoor air conditioning unit 50 in the single-row dehumidification and air heating mode, the ventilation air supplied by the indoor blower 52 is cooled and dehumidified by the indoor evaporator 18. The ventilation air cooled and dehumidified by the indoor evaporator 18 is reheated by the heater core 32 to approach the target blowing temperature TAO based on the opening of the air mixing door 54. The ventilation air at a controlled temperature is blown into the vehicle cabin, so that the air in the vehicle cabin is dehumidified and heated. (b-2) Cooling series dehumidification and air heating mode

[0169] In the heat pump cycle 10 in the cooling row dehumidification and air heating mode, the control device 60 brings the cooling expansion valve 14c into the throttled state compared to the single row dehumidification and air heating mode.

[0170] Therefore, in the heat pump cycle 10, in the cooling-row dehumidification and air heating mode, the refrigerant discharged from the compressor 11 circulates similarly to the single-row dehumidification and air heating mode. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the water-refrigerant heat exchanger 13, the air heating expansion valve 14a in the throttled state, the outdoor heat exchanger 15, the cooling expansion valve 14c in the throttled state, the chiller 20, the suction-side passage 21d, and the suction port of the compressor 11 in this order. That is, the refrigerant circuit is switched to a refrigerant circuit in which the indoor evaporator 18 and the chiller 20 are connected in parallel with the refrigerant flow.

[0171] In the high-temperature side heat medium circuit 30 in the cooling series dehumidification and air heating mode, the control device 60 controls the high-temperature side pump 31 as in the single air cooling mode.

[0172] In the low-temperature side heat medium circuit 40 in the cooling series dehumidification and air heating mode, the control device 60 controls the low-temperature side pump 41 as in the cooling and air cooling mode.

[0173] In the indoor air conditioning unit 50 in the cooling row dehumidification and air heating mode, the control device 60 controls the ventilation power of the indoor fan 52 and the opening of the air mixing door 54 as in the single air cooling mode. In addition, the control device 60 appropriately controls the operations of other control target devices as in the single row dehumidification and air heating mode.

[0174] Therefore, in the heat pump cycle 10 in the cooling series dehumidification and air heating mode, a vapor compression refrigeration cycle is designed in which the water-refrigerant heat exchanger 13 functions as a condenser and the indoor evaporator 18 and the cooler 20 function as evaporators.

[0175] Furthermore, in the cooling-row dehumidification and air heating mode, the outdoor heat exchanger 15 functions as a condenser in a case where the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is higher than the outside air temperature Tam, as in the single-row dehumidification and air heating mode. In a case where the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is lower than the outside air temperature Tam, the outdoor heat exchanger 15 functions as an evaporator.

[0176] In the high-temperature side heat medium circuit 30 in the cooling series dehumidification and air heating mode, the high-temperature side heat medium heated by the water-refrigerant heat exchanger 13 flows into the heater core 32 as in the single-air cooling mode.

[0177] In the low-temperature side heat medium circuit 40 in the cooling series dehumidification and air heating mode, as in the cooling and air cooling mode, the low-temperature side heat medium cooled by the radiator 20 flows through the cooling water passage 70a of the battery 70, so that the battery 70 is cooled.

[0178] In the indoor air conditioning unit 50, in the cooling row dehumidification and air heating mode, the ventilation air is blown into the vehicle cabin at a controlled temperature so that the air in the vehicle cabin is dehumidified and heated, as in the single row dehumidification and air heating mode. (c) Outdoor air heat absorption and air heating mode

[0179] The outside air heat absorption and air heating mode is an operation mode in which the air in the vehicle cabin is heated by blowing heated ventilation air into the vehicle cabin. In the control program, the outside air heat absorption and air heating mode is selected mainly in winter when the outside air temperature Tam is relatively low (equal to or higher than -10°C and lower than 0°C in the present embodiment).

[0180] Examples of the external air heat absorption and heating mode include a single external air heat absorption and heating mode and a cooling external air heat absorption and heating mode. The single external air heat absorption and heating mode is an operation mode in which the air in the vehicle cabin is heated without cooling the battery 70. The cooling external air heat absorption and heating mode is an operation mode in which the battery 70 is cooled while simultaneously heating the air in the vehicle cabin. (c-1) Single outside air heat absorption and air heating mode

[0181] In the heat pump cycle 10 in the single outdoor air heat absorption and air heating mode, the control device 60 places the air heating expansion valve 14a in the throttled state, the air cooling expansion valve 14b in the fully closed state, the cooling expansion valve 14c in the fully closed state, and the bypass-side flow rate control valve 14d in the fully closed state. The control device 60 closes the dehumidification on / off valve 22a and opens the air heating on / off valve 22b.

[0182] Therefore, in the heat pump cycle 10 in the single outdoor air heat absorption and air heating mode, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates in this order through the water-refrigerant heat exchanger 13, the air heating expansion valve 14a in the throttled state, the outdoor heat exchanger 15, the air heating passage 21b, the suction side passage 21d, and the suction port of the compressor 11.

[0183] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 such that the discharge refrigerant pressure Pd detected by the high-pressure side refrigerant temperature-pressure sensor 62b approaches a target high pressure PDO. The target high pressure PDO is determined based on the target blowing temperature TAO with reference to the control map prestored in the control device 60. In the control map, the target high pressure PDO is determined to increase as the target blowing temperature TAO increases.

[0184] The control device 60 also controls the throttle opening of the air heating expansion valve 14a in such a manner that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH.

[0185] In the high-temperature side heat medium circuit 30 in the single outside air heat absorption and air heating mode, the control device 60 controls the high-temperature side pump 31 as in the single air cooling mode.

[0186] In the indoor air conditioning unit 50 in the single outdoor air heat absorption and air heating mode, the control device 60 controls the ventilation power of the indoor fan 52 and the opening of the air mixing door 54 as in the single air cooling mode. The control device 60 appropriately controls the operations of other control target devices.

[0187] Therefore, in the heat pump cycle 10 in the single outdoor air heat absorption and air heating mode, a vapor compression refrigeration cycle is designed in which the water-refrigerant heat exchanger 13 functions as a condenser and the outdoor heat exchanger 15 functions as an evaporator.

[0188] In the single outside air heat absorption and air heating mode, the high-temperature side heat medium heated by the water-refrigerant heat exchanger 13 flows into the heater core 32 as in the single cooling mode.

[0189] In the indoor air conditioning unit 50 in the single outside air heat absorption and air heating mode, the ventilation air supplied from the indoor blower 52 passes through the indoor evaporator 18. The ventilation air that has passed through the indoor evaporator 18 is heated by the heater core 32 to approach the target blowing temperature TAO based on the opening of the air mixing door 54. The ventilation air at a controlled temperature is blown into the vehicle cabin, so that the air in the vehicle cabin is heated. (c-2) Cooling outside air heat absorption and air heating mode

[0190] In the heat pump cycle 10 in the cooling outside air heat absorption and air heating mode, the control device 60 places the cooling expansion valve 14c in the throttled state compared to the single outside air heat absorption and air heating mode. The control device 60 opens the on / off dehumidification valve 22a.

[0191] Therefore, in the heat pump cycle 10, in the cooling outdoor air heat absorption and air heating mode, the refrigerant discharged from the compressor 11 circulates similarly to the single outdoor air heat absorption and air heating mode. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the water-refrigerant heat exchanger 13, the dehumidification passage 21a, the cooling expansion valve 14c in the throttled state, the chiller 20, the suction-side passage 21d, and the suction port of the compressor 11 in this order. That is, the refrigerant circuit is switched to a refrigerant circuit in which the outdoor heat exchanger 15 and the chiller 20 are connected in parallel with the refrigerant flow.

[0192] In the high-temperature side heat medium circuit 30 in the cooling outside air heat absorption and air heating mode, the control device 60 operates the high-temperature side pump 31 as in the single-air cooling mode.

[0193] In the low-temperature side heat medium circuit 40 cooling outside air heat absorption and air heating mode, the control device 60 operates the low-temperature side pump 41 as in the cooling and air heating mode.

[0194] In the indoor air conditioning unit 50 in the cooling outside air heat absorption and air heating mode, the control device 60 controls the ventilation power of the indoor fan 52 and the opening of the air mixing door 54 as in the single air cooling mode. In addition, the control device 60 appropriately controls the operations of other control target devices as in the single outside air heat absorption and air heating mode.

[0195] Therefore, in the heat pump cycle 10 in the cooling outside air heat absorption and air heating mode, a vapor compression refrigeration cycle is designed in which the water-refrigerant heat exchanger 13 functions as a condenser and the outside air heat absorption and air heating mode 15 and the chiller 20 function as evaporators.

[0196] In the high-temperature side heat medium circuit 30, in the cooling outside air heat absorption and air heating mode, the high-temperature side heat medium heated by the water-refrigerant heat exchanger 13 flows into the heater core 32 as in the single-air cooling mode.

[0197] In the low-temperature side heat medium circuit 40 in the cooling outside air heat absorption and air heating mode, as in the cooling and air cooling mode, the low-temperature side heat medium cooled by the radiator 20 flows through the cooling water passage 70a of the battery 70, so that the battery 70 is cooled.

[0198] In the indoor air conditioning unit 50, in the cooling outside air heat absorption and air heating mode, as in the single outside air heat absorption and air heating mode, the ventilation air at a controlled temperature is blown into the vehicle cabin so that the air in the vehicle cabin is heated.

[0199] Next, an operation mode in which the refrigerant flows through the bypass passage 21c will be described. Examples of the operation mode in which the refrigerant flows through the bypass passage 21c include (d) a hot gas air heating mode, (e) a hot gas dehumidification and air heating mode, and (f) a hot gas series dehumidification and air heating mode. (d) Hot gas air heating mode

[0200] The hot gas air heating mode is an operating mode in which the air in the vehicle cabin is heated. In the control program, the hot gas air heating mode is selected when the outside air temperature Tam is extremely low (less than -10°C in the present embodiment) or when it is determined that the heating capacity of the ventilation air in the water-refrigerant heat exchanger 13 is insufficient in the outside air heat absorption and air heating mode.

[0201] If the ventilation air temperature TAV is lower than the target blowing temperature TAO, the control program detects that the heating capacity of the ventilation air is insufficient. The same applies to other operating modes.

[0202] Examples of the hot gas air heating mode include a single hot gas air heating mode and a cooling hot gas air heating mode. The single hot gas air heating mode is an operating mode in which the air in the vehicle cabin is heated without cooling the battery 70. The cooling hot gas air heating mode is an operating mode in which the battery 70 is cooled while simultaneously heating the air in the vehicle cabin. (d-1) Single hot gas air heating mode

[0203] In the heat pump cycle 10 in the single hot gas air heating mode, the control device 60 brings the air heating expansion valve 14a to the fully closed state, brings the air cooling expansion valve 14b to the fully closed state, brings the cooling expansion valve 14c to the throttled state, and brings the bypass-side flow rate control valve 14d to the throttled state. The control device 60 opens the dehumidification on / off valve 22a and closes the air heating on / off valve 22b.

[0204] Therefore, in the heat pump circuit 10 in single hot gas air heating mode, as shown by the solid arrows in Fig. 8, the refrigerant discharged from the compressor 11 circulates in this order through the first three-way junction 12a, the water-refrigerant heat exchanger 13, the dehumidification passage 21a, the cooling expansion valve 14c in the throttled state, the radiator 20, the suction-side passage 21d, and the suction port of the compressor 11. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the first three-way junction 12a, the bypass-side flow rate control valve 14d in the throttled state arranged in the bypass passage 21c, the suction-side passage 21d, and the suction port of the compressor 11 in this order.

[0205] In addition, the control device 60 controls the refrigerant discharge capacity of the compressor 11 in such a manner that the cooler-side refrigerant pressure Pc approaches a predetermined first target low pressure PSO1.

[0206] Controlling the cooler-side refrigerant pressure Pc, which corresponds to the intake refrigerant pressure Ps, to approach a constant pressure is effective for stabilizing a discharge flow rate Gr (mass flow rate) of the compressor 11. Specifically, by generating a saturated gas-phase refrigerant with a constant pressure as the intake refrigerant pressure Ps, the density of the intake refrigerant becomes constant. Therefore, when the intake refrigerant pressure Ps is controlled to approach a constant pressure, the discharge flow rate Gr of the compressor 11 is easily stabilized at the same rotational speed.

[0207] In addition, the control device 60 controls the throttle opening of the bypass-side flow rate control valve 14d in such a manner that the discharge refrigerant pressure Pd approaches the target high pressure PDO.

[0208] The control device 60 also controls the throttle opening of the cooling expansion valve 14c in such a manner that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH.

[0209] In the high-temperature side heat medium circuit 30 in the single hot gas air heating mode, the control device 60 operates the high-temperature side pump 31 as in the single air cooling mode.

[0210] In the low-temperature side heat medium circuit 40 in the single hot gas air heating mode, the control device 60 stops the low-temperature side pump 41.

[0211] In the indoor air conditioning unit 50 in the single hot gas air heating mode, the control device 60 controls the opening of the air mixing door 54 as in the single air cooling mode. In the hot gas air heating mode, the opening of the air mixing door 54 is often controlled so that almost the entire volume of the ventilation air supplied by the indoor fan 52 passes through the heater core 32.

[0212] The control device 60 controls the operation of the inside air / outside air switching device 53 to introduce the inside air into the air conditioning case 51. The control device 60 appropriately controls the operations of other control target devices.

[0213] Therefore, in the heat pump circuit 10 in the single hot gas air heating mode, the state of the refrigerant changes as shown in the Mollier diagram of Fig. 9 is shown.

[0214] First, the flow of the refrigerant discharged from the compressor 11 (point a9 in Fig. 9) is branched at the first three-way connection point 12a. A refrigerant branched at the first three-way connection point 12a flows into the water-refrigerant heat exchanger 13 and radiates heat to the high-temperature side heat medium (from point a9 to point b9 in Fig. 9). This heats the high-temperature side heat medium.

[0215] The refrigerant flowing out of the water-refrigerant heat exchanger 13 flows into the dehumidification passage 21a. The refrigerant flowing into the dehumidification passage 21a flows into the cooling expansion valve 14c and is decompressed (from point b9 to point c9 in Fig. 9).

[0216] The refrigerant decompressed by the cooling expansion valve 14c flows into the cooler 20. In the hot gas air heating mode, no heat exchange occurs between the refrigerant and the low-temperature side heat medium in the cooler 20 because the low-temperature side pump 41 is stopped. The refrigerant flowing out of the cooler 20 flows into the other inlet port of the sixth three-way joint 12f via the fourth three-way joint 12d and the fifth three-way joint 12e.

[0217] The other refrigerant branched at the first three-way junction 12a flows into the bypass passage 21c. The refrigerant flowing into the bypass passage 21c is decompressed when the flow rate is controlled by the bypass-side flow rate control valve 14d (from point a9 to point d9 in Fig. 9). The refrigerant decompressed by the bypass-side flow rate control valve 14d flows into an inlet port of the sixth three-way joint 12f.

[0218] The refrigerant flowing out of the radiator 20 and the refrigerant flowing out of the bypass-side flow rate control valve 14d are combined and mixed at the sixth three-way junction 12f. The refrigerant flowing out of the sixth three-way junction 12f is mixed when passing through the suction-side passage 21d (point e9 in Fig. 9) and is sucked into the compressor 11.

[0219] As described above, in the heat pump cycle 10 in the hot gas air heating mode, refrigerants with different enthalpies, such as the one from the cooler 20 (point c9 in Fig. 9) and the low enthalpy refrigerant flowing out of the bypass passage 21c (point d9 in Fig. 9) flowing high enthalpy refrigerant, mixed and sucked into the compressor 11.

[0220] Therefore, in the heat pump cycle 10 in the hot gas air heating mode, the cooling expansion valve 14c serves as a heating unit side decompression unit.

[0221] In the high-temperature side heat medium circuit 30 in the hot gas air heating mode, the high-temperature side heat medium heated by the water-refrigerant heat exchanger 13 flows into the heater core 32 as in the single air cooling mode.

[0222] In the indoor air conditioning unit 50, in the single hot gas air heating mode, like the single outside air heat absorption and air heating mode, the ventilation air is blown into the vehicle cabin at a controlled temperature so that the air in the vehicle cabin is heated.

[0223] Here, the single hot gas air heating mode is an operation mode performed when the outside air temperature Tam is extremely low. Therefore, when the refrigerant flowing out of the water-refrigerant heat exchanger 13 flows into the outdoor heat exchanger 15, the refrigerant can radiate heat to the outside air in the outdoor heat exchanger 15. When the refrigerant in the outdoor heat exchanger 15 radiates heat to the outside air, the amount of heat that the refrigerant transfers to the ventilation air in the water-refrigerant heat exchanger 13 decreases, and the heating performance of the ventilation air decreases accordingly.

[0224] Since in the single hot gas air heating mode of the present embodiment, the refrigerant circuit is switched to the refrigerant circuit that does not allow the refrigerant flowing out of the water-refrigerant heat exchanger 13 to flow into the outdoor heat exchanger 15, the refrigerant in the outdoor heat exchanger 15 can be prevented from releasing heat to the outside air.

[0225] In the single hot gas air heating mode of the present embodiment, the throttle opening of the cooling expansion valve 14c is controlled in such a way that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH. Consequently, by increasing the refrigerant discharge capacity of the compressor 11, the state of the suction refrigerant (point e9 in Fig. 9) the gas-phase refrigerant with the degree of superheat even if the amount of heat radiated from the discharge refrigerant to the high-temperature side heat medium in the water-refrigerant heat exchanger 13 is increased.

[0226] Therefore, in the single hot gas air heating mode, even at extremely low outside air temperatures Tam, the heat generated by the workload of the compressor 11 can be effectively used to heat the ventilation air and the air in the vehicle cabin can be heated. (d-2) Cooling hot gas air heating mode

[0227] In the cooling hot gas air heating mode, the control device 60 operates the low-temperature side pump 41 of the low-temperature side heat medium circuit 40 to have the predetermined reference pumping capacity compared to the single hot gas air heating mode. Therefore, in the heat pump cycle 10 in the cooling hot gas air heating mode, the refrigerant flowing into the chiller 20 absorbs heat from the low-temperature side heat medium. As a result, the low-temperature side heat medium is cooled. The other operations are similar to those of the single hot gas air heating mode.

[0228] Therefore, in the cooling hot gas air heating mode, the heat generated by the workload of the compressor 11 can be effectively utilized to heat the ventilation air, and the air in the vehicle cabin can be heated, as in the single hot gas air heating mode. In the low-temperature side heat medium circuit 40 in the cooling hot gas air heating mode, the low-temperature side heat medium cooled by the radiator 20 flows through the cooling water passage 70a of the battery 70. As a result, the battery 70 can be cooled. (e) Hot gas dehumidification and air heating mode

[0229] The hot gas dehumidification and air heating mode is an operating mode in which the air in the vehicle cabin is dehumidified and heated. In the control program, the hot gas dehumidification and air heating mode is selected when the outside air temperature Tam is within a predetermined low to medium temperature range (equal to or higher than 0°C and lower than 10°C in the present embodiment).

[0230] Examples of the hot gas dehumidification and air heating mode include a single hot gas dehumidification and air heating mode and a cooling hot gas dehumidification and air heating mode. The single hot gas dehumidification and air heating mode is an operation mode in which the air in the vehicle cabin is dehumidified and heated without cooling the battery 70. The cooling hot gas dehumidification and air heating mode is an operation mode in which the battery 70 is cooled and the air in the vehicle cabin is dehumidified and heated simultaneously. (e-1) Single hot gas dehumidification and air heating mode

[0231] In the heat pump cycle 10 in the single hot gas dehumidification and air heating mode, the control device 60 brings the air heating expansion valve 14a to the fully closed state, brings the air cooling expansion valve 14b to the throttled state, brings the cooling expansion valve 14c to the throttled state, and brings the bypass-side flow rate control valve 14d to the throttled state. The control device 60 opens the dehumidification on / off valve 22a and closes the air heating on / off valve 22b.

[0232] Therefore, in the heat pump circuit 10 in single hot gas dehumidification and air heating mode, as shown by the solid arrows in Fig. 10, the refrigerant discharged from the compressor 11 is similar to the single hot gas air heating mode. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates in this order through the first three-way junction 12a, the water-refrigerant heat exchanger 13, the dehumidification passage 21a, the air-cooling expansion valve 14b in the throttled state, the indoor evaporator 18, the suction-side passage 21d, and the suction port of the compressor 11. That is, the refrigerant circuit is switched to a refrigerant circuit in which the indoor evaporator 18 and the cooler 20 are connected in parallel with the refrigerant flow.

[0233] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 such that the intake refrigerant pressure Ps approaches a predetermined second target low pressure PSO2. The second target low pressure PSO2 is determined such that the refrigerant evaporation temperature in the indoor evaporator 18 is a temperature at which the ventilation air can be dehumidified without causing frost formation on the indoor evaporator 18.

[0234] In addition, the control device 60 controls the throttle opening of the bypass-side flow rate control valve 14d in such a manner that the discharge refrigerant pressure Pd approaches the target high pressure PDO, as in the hot gas air heating mode.

[0235] The control device 60 controls the throttle opening of the air cooling expansion valve 14b to a predetermined throttle opening for the hot gas dehumidification and air heating mode.

[0236] The control device 60 also controls the throttle opening of the cooling expansion valve 14c in such a manner that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH.

[0237] In the high-temperature side heat medium circuit 30 in the single hot gas dehumidification and air heating mode, the control device 60 operates the high-temperature side pump 31 as in the single air cooling mode.

[0238] In the low-temperature side heat medium circuit 40 in the single hot gas dehumidification and air heating mode, the control device 60 stops the low-temperature side pump 41.

[0239] In the indoor air conditioning unit 50 in the single hot gas dehumidification and air heating mode, the control device 60 controls, as in the single air cooling mode, the ventilation power of the indoor fan 52 and the opening of the air mixing door 54. The control device 60 appropriately controls the operations of other control target devices.

[0240] Therefore, in the heat pump cycle 10 in the single hot gas dehumidification and air heating mode, the state of the refrigerant changes as shown in the Mollier diagram of Fig. 11 is shown.

[0241] The flow of the discharge refrigerant discharged from the compressor 11 (point a11 in Fig. 11) is branched at the first three-way connection point 12a. A refrigerant branched at the first three-way connection point 12a flows into the water-refrigerant heat exchanger 13 and radiates heat to the high-temperature side heat medium (from point a11 to point b11 in Fig. 11). As a result, the high-temperature side heat medium is heated.

[0242] The refrigerant flowing out of the water-refrigerant heat exchanger 13 flows into the dehumidification passage 21a. The flow of the refrigerant flowing into the dehumidification passage 21a is branched at the four-way junction 12x. A refrigerant branched at the four-way junction 12x flows into the air-cooling expansion valve 14b and is decompressed (from point b11 to point f11 in Fig. 11).

[0243] The refrigerant decompressed by the air-cooling expansion valve 14b flows into the indoor evaporator 18. The refrigerant flowing into the indoor evaporator 18 exchanges heat with the ventilation air supplied by the indoor fan 52 and evaporates. As a result, the ventilation air is cooled and dehumidified. The refrigerant flowing out of the indoor evaporator 18 flows into an inlet port of the fifth three-way junction 12e via the second check valve 16b.

[0244] The other refrigerant branched at the four-way junction 12x flows into the cooling expansion valve 14c and is decompressed (from point b11 to point c11 in Fig. 11). The refrigerant decompressed by the cooling expansion valve 14c flows into the cooler 20. In the hot gas dehumidification and air heating mode, the cooler 20 does not exchange heat between the refrigerant and the low-temperature side heat medium because the low-temperature side pump 41 is stopped. The refrigerant flowing out of the cooler 20 flows into the other inlet port of the fifth three-way joint 12e.

[0245] At the fifth three-way junction 12e, the flow of refrigerant flowing out of the indoor evaporator 18 and the flow of refrigerant flowing out of the cooler 20 are combined. The refrigerant flowing out of the fifth three-way junction 12e flows into the other inlet port of the sixth three-way junction 12f.

[0246] The other refrigerant branched at the first three-way junction 12a flows into the bypass passage 21c. The refrigerant flowing into the bypass passage 21c is decompressed when the flow rate is controlled by the bypass-side flow rate control valve 14d (from point a11 to point d11 in Fig. 11), as in the hot gas air heating mode. The refrigerant decompressed by the bypass-side flow rate control valve 14d flows into an inlet port of the sixth three-way junction 12f.

[0247] The refrigerant flowing out of the fifth three-way junction 12e and the refrigerant flowing out of the bypass-side flow rate control valve 14d are combined and mixed at the sixth three-way junction 12f. The refrigerant flowing out of the sixth three-way junction 12f is mixed while flowing through the suction-side passage 21d (point e11 in Fig. 11) and is sucked into the compressor 11.

[0248] Here, in Fig. 11, the pressure of the refrigerant decompressed by the air cooling expansion valve 14c (point c11 in Fig. 11) by a lower value than the pressure of the refrigerant decompressed by the air cooling expansion valve 14b (point f11 in Fig. 11), but it is not limited thereto. The pressure of the refrigerant decompressed by the cooling expansion valve 14c may be higher than or equal to the pressure of the refrigerant decompressed by the air-cooling expansion valve 14b.

[0249] As described above, in the heat pump cycle 10, in the hot gas dehumidification and air heating mode, the refrigerant circuit is switched to a refrigerant circuit in which refrigerants with different enthalpies, such as that from the cooler 20 (point c11 in Fig. 11) low enthalpy refrigerant flowing out of the bypass passage 21c (point d11 in Fig. 11) and the refrigerant flowing out of the internal evaporator 18 are mixed and sucked into the compressor 11.

[0250] Therefore, in the heat pump cycle 10 in the hot gas dehumidification and air heating mode, the air cooling expansion valve 14b and the cooling expansion valve 14c serve as the heating unit side decompression unit.

[0251] In the high-temperature side heat medium circuit 30 in the single hot gas dehumidification and air heating mode, the high-temperature side heat medium heated by the water-refrigerant heat exchanger 13 flows into the heater core 32 as in the single air cooling mode. In the interior air conditioning unit 50, in the single hot gas dehumidification and air heating mode, the ventilation air at a controlled temperature is blown into the vehicle cabin, so that the air in the vehicle cabin is dehumidified and heated as in the single row dehumidification and air heating mode.

[0252] Here, the single hot gas dehumidification and air heating mode is an operation mode in which the ventilation air is cooled and dehumidified, and the dehumidified ventilation air is reheated to a desired temperature and blown into the vehicle cabin. Therefore, in the single hot gas dehumidification and air heating mode, it is necessary to control the workload of the compressor 11 in such a way that the temperature of the ventilation air can be reheated to a desired temperature by the heating unit without causing frost formation on the interior evaporator 18.

[0253] In the single hot gas dehumidification and air heating mode of the present embodiment, the refrigerant with relatively high enthalpy flows into the sixth three-way junction 12f via the bypass passage 21c. Even if the refrigerant discharge capacity of the compressor 11 is increased, the suction refrigerant pressure Ps can be prevented from decreasing. This makes it possible to increase the amount of heat radiated from the discharge refrigerant to the high-temperature side heat medium in the water-refrigerant heat exchanger 13 without causing frost formation on the indoor evaporator 18.

[0254] Therefore, in the single hot gas dehumidification and air heating mode, the ventilation air can be heated with a higher heating capacity than in the series dehumidification and air heating mode. (e-2) Cooling hot gas dehumidification and air heating mode

[0255] In the cooling, hot gas dehumidification, and air heating mode, the controller 60 operates the low-temperature-side pump 41 to have the predetermined reference pumping capacity compared to the single-hot gas dehumidification and air heating mode. Therefore, in the heat pump cycle 10 in the cooling, hot gas dehumidification, and air heating mode, the refrigerant flowing into the chiller 20 absorbs heat from the low-temperature-side heat medium. This cools the low-temperature-side heat medium. The other operations are similar to those in the single-hot gas dehumidification and air heating mode.

[0256] Therefore, in the cooling hot gas dehumidification and air heating mode, the ventilation air is heated with a higher heating efficiency than in the series dehumidification and air heating mode, and the air in the vehicle cabin can be dehumidified and heated as in the single hot gas dehumidification and air heating mode. In the low-temperature side heat medium circuit 40 in the cooling hot gas dehumidification and air heating mode, the low-temperature side heat medium cooled by the radiator 20 flows through the cooling water passage 70a of the battery 70. This allows the battery 70 to be cooled. (f) Hot gas series dehumidification and air heating mode

[0257] The hot gas series dehumidification and air heating mode is an operating mode in which the air in the vehicle cabin is dehumidified and heated. The control program selects the hot gas series dehumidification and air heating mode when it is determined that the heating performance of the ventilation air in the water-refrigerant heat exchanger 13 is insufficient in the series dehumidification and air heating mode.

[0258] Examples of the hot gas row dehumidification and air heating mode include a single hot gas row dehumidification and air heating mode and a cooling hot gas row dehumidification and air heating mode. The single hot gas row dehumidification and air heating mode is an operation mode in which the air in the vehicle cabin is dehumidified and heated without cooling the battery 70. The cooling hot gas row dehumidification and air heating mode is an operation mode in which the battery 70 is cooled while simultaneously dehumidifying and heating the air in the vehicle cabin. (f-1) Single hot gas row dehumidification and air heating mode

[0259] In the heat pump cycle 10 in the single hot gas series dehumidification and air heating mode, the control device 60 places the air heating expansion valve 14a in the throttled state, the air cooling expansion valve 14b in the throttled state, the cooling expansion valve 14b in the throttled state, the cooling expansion valve 14c in the throttled state, and the bypass-side flow rate control valve 14d in the throttled state. In addition, the control device 60 closes the on / off dehumidification valve 22a and also closes the on / off air heating valve 22b.

[0260] Therefore, in the heat pump circuit 10 in single hot gas row dehumidification and air heating mode, as indicated by the solid arrows in Fig. 12, the refrigerant discharged from the compressor 11 is circulated similarly to the cooling series dehumidification and air heating mode. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the first three-way junction 12a, the bypass-side flow rate control valve 14d in the throttled state arranged in the bypass passage 21c, the sixth three-way junction 12f, the suction-side passage 21d, and the suction port of the compressor 11 in this order.

[0261] In addition, the control device 60 controls the refrigerant discharge capacity of the compressor 11 in such a manner that the suction refrigerant pressure Ps approaches the predetermined second target low pressure PSO2, as in the hot gas dehumidification and air heating mode.

[0262] In addition, the control device 60 controls the throttle opening of the bypass-side flow rate control valve 14d in such a manner that the discharge refrigerant pressure Pd approaches the target high pressure PDO, as in the hot gas air heating mode.

[0263] The control device 60 controls the throttle opening of the air heating expansion valve 14a and the throttle opening of the air cooling expansion valve 14b to a predetermined throttle opening for the hot gas series dehumidification and air heating mode.

[0264] The control device 60 also controls the throttle opening of the cooling expansion valve 14c in a manner that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH, as in the hot gas dehumidification and air heating mode.

[0265] In the high-temperature side heat medium circuit 30 in the single hot gas dehumidification and air heating mode, the control device 60 operates the high-temperature side pump 31 as in the single air cooling mode.

[0266] In the low-temperature side heat medium circuit 40 in the single hot gas dehumidification and air heating mode, the control device 60 stops the low-temperature side pump 41.

[0267] In the indoor air conditioning unit 50 in the single hot gas dehumidification and air heating mode, the control device 60 controls the ventilation power of the indoor fan 52 and the opening of the air mixing door 54 as in the single cooling mode. The control device 60 controls the operations of other control target devices accordingly.

[0268] Therefore, in the heat pump circuit 10 in the hot gas series dehumidification and air heating mode, the state of the refrigerant changes, as shown in the Mollier diagram in Fig. 13 is shown. Fig. 13 shows an example in which the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is higher than the outside air temperature Tam.

[0269] The flow of the discharge refrigerant discharged from the compressor 11 (point a13 in Fig. 13) is branched off at the first three-way junction 12a. A refrigerant branched off at the first three-way junction 12a flows into the water-refrigerant heat exchanger 13 and radiates heat to the high-temperature side heat medium (from point a13 to point b131 in Fig. 13). As a result, the high-temperature side heat medium is heated.

[0270] The refrigerant flowing out of the water-refrigerant heat exchanger 13 flows into the air heating expansion valve 14a and is decompressed (from point b131 to point b132 in Fig. 13). The refrigerant decompressed by the air heating expansion valve 14a flows into the outdoor heat exchanger 15. In the Fig. In the example shown in Figure 13, the refrigerant flowing into the outdoor heat exchanger 15 exchanges heat with the outside air to reduce the enthalpy (from point b132 to point b133 in Fig. 13).

[0271] The flow of refrigerant flowing from the outdoor heat exchanger 15 is branched at the four-way junction 12x. A refrigerant branched at the four-way junction 12x flows into the air-cooling expansion valve 14b and is decompressed (from point b133 to point f13 in Fig. 13).

[0272] The refrigerant decompressed by the air cooling expansion valve 14b flows into the indoor evaporator 18, exchanges heat with the ventilation air supplied from the indoor fan 52, and evaporates (from point f13 to point e13 in Fig. 13), as in the hot gas dehumidification and air heating mode. This cools and dehumidifies the ventilation air. The refrigerant flowing out of the indoor evaporator 18 flows through the second check valve 16b into an inlet port of the fifth three-way junction 12e.

[0273] The other refrigerant branched off at the four-way connection 12x flows into the cooling expansion valve 14c and is decompressed (from point b133 to point c13 in Fig. 13), as in the hot gas air heating mode. The refrigerant decompressed by the cooling expansion valve 14c flows into the radiator 20. The refrigerant flowing out of the radiator 20 flows into the other inlet port of the fifth three-way junction 12e.

[0274] The flow of refrigerant flowing out of the indoor evaporator 18 and the flow of refrigerant flowing out of the cooler 20 are combined at the fifth three-way junction 12e, as in the hot gas air heating mode. The refrigerant flowing out of the fifth three-way junction 12e flows into the other inlet port of the sixth three-way junction 12f.

[0275] The other refrigerant branched at the first three-way junction 12a flows into the bypass passage 21c. The refrigerant flowing into the bypass passage 21c is decompressed when the flow rate is controlled by the bypass-side flow rate control valve 14d (from point a13 to point d13 in Fig. 13), as in the hot gas air heating mode. The refrigerant decompressed by the bypass-side flow rate control valve 14d flows into an inlet port of the sixth three-way junction 12f.

[0276] The refrigerant flowing out of the fifth three-way junction 12e and the refrigerant flowing out of the bypass-side flow rate control valve 14d are combined and mixed at the sixth three-way junction 12f, as in the hot gas dehumidification and air heating mode. The refrigerant flowing out of the sixth three-way junction 12f is mixed while flowing through the suction-side passage 21d (point e13 in Fig. 13) and is sucked into the compressor 11.

[0277] Here in Fig. 13 is the pressure of the refrigerant decompressed by the cooling expansion valve 14c (point c13 in Fig. 13), with a value lower than the pressure of the refrigerant decompressed by the air cooling expansion valve 14b (point f13 in Fig. 13), but it is not limited thereto. The pressure of the refrigerant decompressed by the cooling expansion valve 14c may be higher than or equal to the pressure of the refrigerant decompressed by the air-cooling expansion valve 14b.

[0278] As described above, in the heat pump cycle 10, in the hot gas series dehumidification and air heating mode, the refrigerant circuit is switched to a refrigerant circuit in which refrigerants with different enthalpies, such as the low enthalpy refrigerant flowing out of the cooler 20 (point c13 in Fig. 13), the high enthalpy refrigerant flowing out of the bypass passage 21c (point d13 in Fig. 13), and the refrigerant flowing out of the internal evaporator 18 are mixed and sucked into the compressor 11.

[0279] Therefore, in the heat pump cycle 10 in the hot gas series dehumidification and air heating mode, the air heating expansion valve 14a, the air cooling expansion valve 14b and the cooling expansion valve 14c serve as the heating unit side decompression unit.

[0280] In the high-temperature side heat medium circuit 30 in the single hot gas series dehumidification and air heating mode, the high-temperature side heat medium heated by the water-refrigerant heat exchanger 13 flows into the heater core 32 as in the single air cooling mode.

[0281] In the indoor air conditioning unit 50 in the hot gas row dehumidification and air heating mode, the ventilation air is blown into the vehicle cabin at a controlled temperature so that the air in the vehicle cabin is dehumidified and heated, as in the single row dehumidification and air heating mode.

[0282] In the hot gas series dehumidification and air heating mode, it is necessary to control the refrigerant discharge capacity of the compressor 11 in such a way that the heating unit can heat the ventilation air to a desired temperature without causing frost formation on the indoor evaporator 18, as in the hot gas dehumidification and air heating mode.

[0283] In the single hot-gas row dehumidification and air heating mode of the present embodiment, the refrigerant with relatively high enthalpy flows into the sixth three-way junction 12f via the bypass passage 21c. Therefore, even if the refrigerant discharge capacity of the compressor 11 is increased, it is possible to increase the amount of heat radiated from the discharge refrigerant to the ventilation air in the water-refrigerant heat exchanger 13 without causing frost formation on the indoor evaporator 18, as in the single hot-gas row dehumidification and air heating mode.

[0284] As a result, the ventilation air can be heated with a higher heating capacity in the single hot gas row dehumidification and air heating mode than in the row dehumidification and air heating mode. (f-2) Cooling hot gas series dehumidification and air heating mode

[0285] In the cooling hot-gas row dehumidification and air heating mode, the control device 60 operates the low-temperature-side pump 41 to achieve the specified reference pump capacity, compared to the single hot-gas row dehumidification and air heating mode. Therefore, in the heat pump cycle 10 in the cooling hot-gas row dehumidification and air heating mode, the refrigerant flowing into the chiller 20 absorbs heat from the low-temperature-side heat medium. As a result, the low-temperature-side heat medium is cooled. The other operations are similar to those in the single hot-gas row dehumidification and air heating mode.

[0286] Therefore, in the cooling hot gas series dehumidification and air heating mode, the ventilation air is heated with a higher heating efficiency than in the series dehumidification and air heating mode, and the air in the vehicle cabin can be dehumidified and heated as in the single hot gas series dehumidification and air heating mode. In the low-temperature side heat medium circuit 40 in the cooling hot gas series dehumidification and air heating mode, the low-temperature side heat medium cooled by the radiator 20 flows through the cooling water passage 70a of the battery 70. This allows the battery 70 to be cooled.

[0287] As described above, in the vehicle air conditioner 1 of the present embodiment, by switching the operation mode, comfortable air conditioning in the vehicle cabin and appropriate temperature control of the battery 70, which is an on-vehicle device, can be performed.

[0288] In the vehicle air conditioner 1 of the present embodiment, in the operation modes (d) hot gas air heating mode, (e) hot gas dehumidification and air heating mode, and (f) hot gas series dehumidification and air heating mode, the refrigerant cycle is switched to a refrigerant cycle in which refrigerants having different enthalpies are mixed at the sixth three-way junction 12f, which is a joining portion, and are sucked into the compressor 11.

[0289] In a heat pump cycle device where refrigerants with different enthalpies are mixed and drawn into a compressor, insufficient mixing of the refrigerants can cause liquid compression of the compressor. This is because if the refrigerants are insufficiently mixed and a temperature distribution is created in a suction refrigerant, the liquid-phase refrigerant may be unevenly distributed in the suction refrigerant. When the compressor draws in the unevenly distributed liquid-phase refrigerant, liquid compression may occur.

[0290] On the other hand, in the vehicle air conditioner 1 of the present embodiment, since the suction-side flow path length L1 is equal to or longer than the expansion distance Lv, the suction refrigerant can be made homogeneous. Therefore, uneven distribution of the liquid-phase refrigerant in the suction refrigerant can be prevented, so that liquid compression of the compressor 11 can be prevented. That is, it is possible to protect the compressor 11.

[0291] Furthermore, the intake-side flow path length L1 can be easily controlled by adjusting the length of the intake-side passage 21d. Therefore, the productivity of the vehicle air conditioner 1 is less likely to deteriorate to make the intake refrigerant sufficiently homogeneous.

[0292] Therefore, according to the vehicle air conditioner 1 of the present embodiment, even in the heat pump cycle device in which refrigerants with different enthalpies are mixed and sucked into the compressor, the compressor 11 can be protected without deteriorating productivity. In other words, in the heat pump cycle device in which refrigerants with different enthalpies are mixed and sucked into the compressor, the compressor can be protected while preventing deterioration in productivity.

[0293] In the vehicle air conditioner 1 of the present embodiment, the detection unit flow path length L2 is equal to or longer than the expansion distance Lv. As a result, the refrigerant to be detected by the intake refrigerant temperature sensor 62f can be made homogeneous. The control device 60 can accurately determine the superheat degree SH of the intake refrigerant and appropriately control the operations of the various control target devices. As a result, the compressor 11 can be more reliably protected.

[0294] In the vehicle air conditioner 1 of the present embodiment, the refrigerant passage in the sixth three-way junction 12f, which is a merging portion, is formed so that the flow direction of the main flow of the heater-side refrigerant immediately before merging and the flow direction of the main flow of the bypass-side refrigerant immediately before merging intersect with each other. Accordingly, the average flow velocity Uv of the droplets and the gas-phase refrigerant at the merging point MX of the sixth three-way junction 12f can be reduced. As a result, the expansion distance Lv can be reduced, as shown in Formula F15. (Second embodiment)

[0295] The present embodiment describes an example in which the arrangement of the intake refrigerant temperature sensor 62f in the vehicle air conditioner 1 of the first embodiment is changed.

[0296] Specifically, the compressor 11 of the present embodiment has a housing that forms a suction port and the like. A mounting portion of the suction refrigerant temperature sensor 62f for detecting the temperature of a suction refrigerant is formed in the housing. Consequently, in the vehicle air conditioning system 1 of the present embodiment, as shown in Fig. 14, the suction refrigerant temperature sensor 62f is arranged at the suction port of the compressor 11.

[0297] Other configurations and operations are similar to those in the first embodiment. Therefore, similar effects to those in the first embodiment can be achieved.

[0298] Furthermore, in the vehicle air conditioner 1 of the present embodiment, the intake-side flow path length L1 is substantially equal to the detection unit flow path length L2. Therefore, compared with the vehicle air conditioner 1 described in the first embodiment, the intake-side flow path length L1 can be reduced to further prevent deterioration in productivity. (Third embodiment)

[0299] The present embodiment describes an example in which a storage 23 is added to the heat pump cycle 10 in the vehicle air conditioner 1 of the first embodiment.

[0300] More precisely, as in Fig. 15, the accumulator 23 is arranged in the suction-side passage 21d. The accumulator 23 is a low-pressure gas-liquid separation unit that separates the refrigerant flowing through the suction-side passage 21d into gas and liquid and stores the separated liquid-phase refrigerant as excess refrigerant in the cycle. The suction port side of the compressor 11 is connected to a gas-phase refrigerant outlet port of the accumulator 23. The suction refrigerant temperature sensor 62f is arranged on the downstream side of the gas-phase refrigerant outlet port of the accumulator 23 in the refrigerant flow.

[0301] Other configurations and operations are similar to those in the first embodiment. Therefore, similar effects to those in the first embodiment can be achieved.

[0302] Furthermore, in the vehicle air conditioner 1 of the present embodiment, the accumulator 23 forms a portion with an enlarged passage sectional area in the suction-side passage 21d. Accordingly, the average flow velocity Uv of the droplets and the gas-phase refrigerant at the junction MX of the sixth three-way junction 12f can be reduced. This allows the expansion distance Lv to be reduced, as shown in Formula F15 described in the first embodiment.

[0303] Therefore, it is possible to protect the compressor 11 more reliably by setting the suction side flow path length L1 and the detection unit flow path length L2 to values ​​similar to those in the first embodiment.

[0304] If the accumulator 23 is arranged in the suction-side passage 21d, there is a possibility that the liquid-phase refrigerant stored in the accumulator 23 will be drawn upward, causing the liquid level of the accumulator 23 to become unstable, i.e., a so-called liquid level loss may occur. If a liquid level loss occurs in the accumulator 23, the dryness of the suction refrigerant may decrease, or the return amount of refrigerant oil to the compressor 11 may be insufficient.

[0305] The present inventors have confirmed that by setting the suction-side flow path length L1 and the detection unit flow path length L2 to be equal to or longer than the expansion distance Lv, the superheat degree SH and the dryness Rx of the suction refrigerant can be appropriately controlled and the liquid compression of the compressor 11 can be reliably prevented. (Fourth embodiment)

[0306] The present embodiment describes an example in which the arrangement of the sixth three-way junction 12f, which is a joining portion, is changed in the vehicle air conditioner 1 of the first embodiment.

[0307] More precisely, as in Fig. As shown in Fig. 16, the sixth three-way junction 12f of the present embodiment is arranged in the refrigerant flow path from the outlet port of the cooling expansion valve 14c to the inlet port of the refrigerant passage in the radiator 20. Therefore, the radiator 20 of the present embodiment is a heat exchanger arranged in the suction-side passage 21d and exchanging heat between the refrigerant and the low-temperature side heat medium. The suction refrigerant temperature sensor 62f is arranged on the downstream side of the refrigerant passage outlet port in the radiator 20.

[0308] Other configurations and operations are similar to those in the first embodiment. Therefore, similar effects to those in the first embodiment can be achieved.

[0309] Furthermore, in the vehicle air conditioner 1 of the present embodiment, since the cooler 20 is disposed in the intake-side passage 21d, the cooler 20 can form a portion with an enlarged passage sectional area in a part of the intake-side passage 21d. Accordingly, the average flow velocity Uv of the droplets and the gas-phase refrigerant at the junction MX of the sixth three-way junction 12f can be reduced, and thus the expansion distance Lv can be reduced, as in the third embodiment.

[0310] Therefore, it is possible to protect the compressor 11 more reliably by setting the suction side flow path length L1 and the detection unit flow path length L2 to values ​​similar to those in the first embodiment. (Fifth embodiment)

[0311] In the present embodiment, the heat pump cycle device according to the present disclosure is applied to a vehicle air conditioner 1a. The vehicle air conditioner 1a is an air conditioner having a vehicle-onboard device temperature control function similar to the vehicle air conditioner 1 described in the first embodiment. The vehicle air conditioner 1a includes a heat pump cycle 10a.

[0312] As in Fig.17, the heat pump cycle 10a includes an indoor condenser 131 and a receiving device 24 instead of the water-refrigerant heat exchanger 13 and the high-temperature side heat medium circuit 30, compared to the heat pump cycle 10 described in the first embodiment.

[0313] In the heat pump cycle 10a, an inlet port side of a refrigerant passage in the indoor condenser 131 is connected to an outlet port of the first three-way junction 12a. The indoor condenser 131 is arranged in the air conditioning case 51 of the indoor air conditioning unit 50, similar to the heater core 32 described in the first embodiment.

[0314] The indoor condenser 131 is a heating heat exchanger that exchanges heat between the high-pressure refrigerant discharged from the compressor 11 and the ventilation air passing through the indoor evaporator 18 to heat the ventilation air. Therefore, the indoor condenser 131 is a heating unit that heats the ventilation air as a heating object using a discharge refrigerant branched at the first three-way junction 12a as a heat source.

[0315] In the heat pump cycle 10a, one inlet port side of the receiving device 24 is connected to the other outlet port of the second three-way junction 12b. The refrigerant passage from the other outlet port of the second three-way junction 12b to an inlet port of the receiving device 24 is an inlet port side passage 21e. A first inlet port side ON / OFF valve 22c and a seventh three-way junction 12g are arranged in the inlet port side passage 21e.

[0316] The receiver 24 is a high-pressure-side gas-liquid separation unit that separates a refrigerant flowing into the receiver into gas and liquid and stores the separated liquid-phase refrigerant as excess refrigerant in the cycle. The receiver 24 causes the separated liquid-phase refrigerant to flow downstream of a liquid-phase refrigerant outlet port.

[0317] The first inlet-port-side ON / OFF valve 22c is an ON / OFF valve that opens and closes the inlet-port-side passage 21e. Specifically, the first inlet-port-side ON / OFF valve 22c opens and closes a refrigerant passage from the other outlet port of the second three-way junction 12b to an inlet port of the seventh three-way junction 12g in the inlet-port-side passage 21e. The first inlet-port-side ON / OFF valve 22c is a refrigerant cycle switching unit.

[0318] An inlet port side of an eighth three-way junction 12h is connected to an outlet port of the second three-way junction 12b. A second inlet port side ON / OFF valve 22d is disposed in a refrigerant passage from an outlet port of the second three-way junction 12b to an inlet port of the eighth three-way junction 12h. The second inlet port side ON / OFF valve 22d opens and closes the refrigerant passage from an outlet port of the second three-way junction 12b to an inlet port of the eighth three-way junction 12h. The second inlet port side ON / OFF valve 22d is the refrigerant circuit switching unit.

[0319] One inlet port side of the air heating expansion valve 14a is connected to an outlet port of the eighth three-way joint 12h. The other inlet port of the seventh three-way joint 12g, which is arranged in the inlet port side passage 21e, is connected to an outlet port of the third three-way joint 12c, which is connected to the outlet port side of the outdoor heat exchanger 15 via the first check valve 16a.

[0320] The other inlet port side of the eighth three-way joint 12h is connected to a liquid-phase refrigerant outlet port of the receiver 24. The refrigerant passage from the outlet port of the receiver 24 to the other inlet port of the eighth three-way joint 12h is an outlet port side passage 21f. A ninth three-way joint 12i and a third check valve 16c are arranged in the outlet port side passage 21f.

[0321] The third check valve 16c allows the refrigerant to flow from the ninth three-way joint 12i side to the eighth three-way joint 12h side and prevents the refrigerant from flowing from the eighth three-way joint 12h side to the ninth three-way joint 12i side.

[0322] An inlet port side of a tenth three-way junction 12j is connected to the other outlet port of the ninth three-way junction 12i. A refrigerant inlet port side of the indoor evaporator 18 is connected to an outlet port of the tenth three-way junction 12j via the air-cooling expansion valve 14b. An inlet port side of a refrigerant passage in the radiator 20 is connected to the other outlet port of the tenth three-way junction 12j via the cooling expansion valve 14c.

[0323] In the heat pump cycle 10a, a suction port side of the compressor 11 is connected to the outlet port of the fourth three-way connection point 12d.

[0324] In the heat pump cycle 10a, the sixth three-way junction 12f is arranged in the refrigerant flow path from the outlet port of the cooling expansion valve 14c to the inlet port of the refrigerant passage in the radiator 20, as in the fourth embodiment. Therefore, the radiator 20 of the present embodiment is a heat exchanger arranged in the suction-side passage 21d and exchanges heat between the refrigerant and the low-temperature side heat medium. The suction refrigerant temperature sensor 62f is arranged on the downstream side of the refrigerant flow from the outlet port of the refrigerant passage in the radiator 20.

[0325] Other configurations of the vehicle air conditioner 1a are similar to those of the vehicle air conditioner 1 described in the first embodiment. That is, in the vehicle air conditioner 1a of the present embodiment, the intake-side flow path length L1 is equal to or longer than the expansion distance Lv. In addition, the detection unit flow path length L2 is equal to or longer than the expansion distance Lv.

[0326] Next, the operation of the vehicle air conditioner 1a of the present embodiment with the above-described configuration will be described. In the vehicle air conditioner 1a of the present embodiment, various operation modes are switched to perform air conditioning in the vehicle cabin and temperature control of the battery 70, as in the first embodiment. The detailed operation of each operation mode will be described below. (a-1) Single air cooling mode

[0327] In the heat pump cycle 10a in the single air-cooling mode, the control device 60 brings the air-heating expansion valve 14a to a fully open state, brings the air-cooling expansion valve 14b to a throttled state, brings the cooling expansion valve 14c to a fully closed state, and brings the bypass-side flow rate control valve 14d to a fully closed state. In addition, the control device 60 closes the air-heating ON / OFF valve 22b, closes the first inlet-port-side ON / OFF valve 22c, and opens the second inlet-port-side ON / OFF valve 22d.

[0328] Therefore, in the heat pump cycle 10a in the single-air cooling mode, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the indoor condenser 131, the air-heating expansion valve 14a in the fully open state, the outdoor heat exchanger 15, the receiver 24, the air-cooling expansion valve 14b in the throttled state, the indoor evaporator 18, and the suction port of the compressor 11 in this order. The control device 60 appropriately controls the operations of other control target devices.

[0329] Therefore, in the heat pump cycle 10a in the single air cooling mode, a vapor compression refrigeration cycle is designed in which the indoor condenser 131 and the outdoor heat exchanger 15 function as condensers and the indoor evaporator 18 functions as an evaporator.

[0330] In the interior air conditioning unit 50 in the single air cooling mode, the ventilation air at a controlled temperature is blown into the vehicle cabin so that the air in the vehicle cabin is cooled, as in the first embodiment. (a-2) Cooling and air cooling mode

[0331] In the heat pump cycle 10a in the cooling and air cooling mode, the control device 60 brings the cooling expansion valve 14c into the throttled state, compared to the single air cooling mode.

[0332] Therefore, in the heat pump cycle 10a, in the cooling and air-cooling mode, the refrigerant discharged from the compressor 11 circulates similarly to the air-cooling mode. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the indoor condenser 131, the air-heating expansion valve 14a in the fully open state, the outdoor heat exchanger 15, the receiver 24, the cooling expansion valve 14c in the throttled state, the radiator 20, and the suction port of the compressor 11 in this order. That is, the refrigerant circuit is switched to a refrigerant circuit in which the indoor evaporator 18 and the radiator 20 are connected in parallel to the refrigerant flow.

[0333] In the low-temperature side heat medium circuit 40 in the cooling and air-cooling mode, the control device 60 controls the operation of the low-temperature side pump 41 similarly to the cooling and air-cooling mode of the first embodiment. The control device 60 appropriately controls the operations of other control target devices.

[0334] Therefore, in the heat pump cycle 10a in the cooling and air cooling mode, a vapor compression refrigeration cycle is designed in which the indoor condenser 131 and the outdoor heat exchanger 15 function as condensers and the indoor evaporator 18 and the cooler 20 function as evaporators.

[0335] In the low-temperature side heat medium circuit 40 in the cooling and air cooling mode, the battery 70 is cooled as in the first embodiment.

[0336] In the interior air conditioning unit 50 in the cooling and air cooling mode, the ventilation air at a controlled temperature is blown into the vehicle cabin so that the air in the vehicle cabin is cooled, as in the first embodiment. (b-1) Single-row dehumidification and air heating mode

[0337] In the heat pump cycle 10a in the single-row dehumidification and air heating mode, the control device 60 places the air heating expansion valve 14a in the throttled state, the air cooling expansion valve 14b in the throttled state, the cooling expansion valve 14c in the fully closed state, and the bypass-side flow rate control valve 14d in the fully closed state. In addition, the control device 60 closes the air heating ON / OFF valve 22b, closes the first inlet-port-side ON / OFF valve 22c, and opens the second inlet-port-side ON / OFF valve 22d.

[0338] Therefore, in the heat pump cycle 10a in the single-row dehumidification and air heating mode, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the indoor condenser 131, the air-heating expansion valve 14a in the throttled state, the outdoor heat exchanger 15, the receiver 24, the air-cooling expansion valve 14b in the throttled state, the indoor evaporator 18, and the suction port of the compressor 11 in this order. The control device 60 appropriately controls the operations of other control target devices.

[0339] Therefore, in the heat pump cycle 10a in the single-row dehumidification and air heating mode, a vapor compression refrigeration cycle is designed in which the indoor condenser 131 and the outdoor heat exchanger 15 function as condensers and the indoor evaporator 18 functions as an evaporator.

[0340] In the indoor air conditioning unit 50 in the single-air cooling mode, the ventilation air whose temperature and humidity have been regulated is blown into the vehicle cabin, so that the air in the vehicle cabin is dehumidified and heated, as in the first embodiment. Since the heat pump cycle 10a includes the receiver 24, the single-row dehumidification and heating mode is performed in the temperature range where the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is higher than the outdoor air temperature Tam. (b-2) Cooling series dehumidification and air heating mode

[0341] In the heat pump cycle 10a in the cooling row dehumidification and air heating mode, the controller 60 brings the cooling expansion valve 14c into the throttled state, compared to the single row dehumidification and air heating mode.

[0342] Therefore, in the heat pump cycle 10a, in the cooling-row dehumidification and air heating mode, the refrigerant discharged from the compressor 11 circulates similarly to the single-row dehumidification and air heating mode. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the indoor condenser 131, the air-heating expansion valve 14a in the fully open state, the outdoor heat exchanger 15, the receiver 24, the cooling expansion valve 14c in the throttled state, the chiller 20, and the suction port of the compressor 11 in this order. That is, the refrigerant circuit is switched to a refrigerant circuit in which the indoor evaporator 18 and the chiller 20 are connected in parallel to the refrigerant flow.

[0343] In the low-temperature side heat medium circuit 40 in the cooling series dehumidification and air heating mode, the control device 60 controls the low-temperature side pump 41 as in the cooling and air cooling mode. The control device 60 controls the operations of other control target devices as appropriate.

[0344] Therefore, in the heat pump cycle 10a in the cooling series dehumidification and air heating mode, a vapor compression refrigeration cycle is designed in which the indoor condenser 131 and the outdoor heat exchanger 15 function as condensers and the indoor evaporator 18 and the cooler 20 function as evaporators.

[0345] In the low-temperature side heat medium circuit 40 in the cooling series dehumidification and air heating mode, the battery 70 is cooled as in the first embodiment.

[0346] In the indoor air conditioning unit 50 in the cooling-series dehumidification and air heating mode, the ventilation air whose temperature and humidity have been regulated is blown into the vehicle cabin, so that the air in the vehicle cabin is dehumidified and heated, as in the first embodiment. Since the heat pump cycle 10a includes the receiver 24, the cooling-series dehumidification and air heating mode is performed in the temperature range where the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is higher than the outdoor air temperature Tam. (c-1) Single outside air heat absorption and air heating mode

[0347] In the heat pump cycle 10a in the single outdoor air heat absorption and air heating mode, the control device 60 places the air heating expansion valve 14a in the throttled state, the air cooling expansion valve 14b in the fully closed state, the cooling expansion valve 14c in the fully closed state, and the bypass-side flow rate control valve 14d in the fully closed state. In addition, the control device 60 opens the air heating on / off valve 22b, opens the first inlet-port-side on / off valve 22c, and closes the second inlet-port-side on / off valve 22d.

[0348] Therefore, in the heat pump cycle 10a, in the single outdoor air heat absorption and air heating mode, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the indoor condenser 131, the receiver 24, the air-heating expansion valve 14a in the throttled state, the outdoor heat exchanger 15, the air-heating passage 21b, and the suction port of the compressor 11 in this order. The control device 60 appropriately controls the operations of other control target devices.

[0349] Therefore, in the heat pump cycle 10a in the single outdoor air heat absorption and air heating mode, a vapor compression refrigeration cycle is designed in which the indoor condenser 131 functions as a condenser and the outdoor heat exchanger 15 functions as an evaporator.

[0350] In the indoor air conditioning unit 50 in the single outside air heat absorption and air heating mode, as in the first embodiment, the ventilation air having a controlled temperature is blown into the vehicle cabin so that the air in the vehicle cabin is heated. (c-2) Cooling outside air heat absorption and air heating mode

[0351] In the heat pump cycle 10a in the cooling outside air heat absorption and air heating mode, the control device 60 brings the cooling expansion valve 14c into the throttled state, compared to the single outside air heat absorption and air heating mode.

[0352] Therefore, in the heat pump cycle 10a, in the cooling outside air heat absorption and air heating mode, the refrigerant discharged from the compressor 11 circulates similarly to the single outside air heat absorption and air heating mode. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the indoor condenser 131, the receiver 24, the cooling expansion valve 14c in the throttled state, the chiller 20, and the suction port of the compressor 11 in this order. That is, the refrigerant circuit is switched to a refrigerant circuit in which the outdoor heat exchanger 15 and the chiller 20 are connected in parallel with the refrigerant flow.

[0353] In the low-temperature side heat medium circuit 40 in the cooling outside air heat absorption and air heating mode, the control device 60 operates the low-temperature side pump 41 as in the cooling and air cooling mode. The control device 60 appropriately controls the operations of other control target devices.

[0354] Therefore, in the heat pump cycle 10a in the cooling outside air heat absorption and air heating mode, a vapor compression refrigeration cycle is designed in which the indoor condenser 131 functions as a condenser and the outdoor heat exchanger 15 and the cooler 20 function as evaporators.

[0355] In the low-temperature side heat medium circuit 40 in the cooling outside air heat absorption and air heating mode, the battery 70 is cooled as in the first embodiment.

[0356] In the indoor air conditioning unit 50 in the cooling outside air heat absorption and air heating mode, as in the first embodiment, the ventilation air having a controlled temperature is blown into the vehicle cabin so that the air in the vehicle cabin is heated. (d-1) Single hot gas air heating mode

[0357] In the heat pump cycle 10a in the single hot gas air heating mode, the control device 60 brings the air heating expansion valve 14a to the fully closed state, brings the air cooling expansion valve 14b to the fully closed state, brings the cooling expansion valve 14c to the throttled state, and brings the bypass-side flow rate control valve 14d to the throttled state. In addition, the control device 60 closes the air heating on / off valve 22b, opens the first inlet-port-side on / off valve 22c, and closes the second inlet-port-side on / off valve 22d.

[0358] Therefore, in the heat pump cycle 10a in the single hot gas air heating mode, the refrigerant discharged from the compressor 11 circulates through the first three-way junction 12a, the indoor condenser 131, the receiver 24, the cooling expansion valve 14c in the throttled state, the sixth three-way junction 12f, the radiator 20, and the suction port of the compressor 11 in this order. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the first three-way junction 12a, the bypass-side flow rate control valve 14d in the throttled state arranged in the bypass passage 21c, the sixth three-way junction 12f, the radiator 20, and the suction port of the compressor 11 in this order.

[0359] The control device 60 also controls the throttle opening of the cooling expansion valve 14c such that the superheat degree SH of the intake refrigerant approaches the reference superheat degree KSH. The control device 60 appropriately controls the operations of other control target devices, as in the first embodiment. Therefore, in the hot gas air heating mode, the cooling expansion valve 14c serves as the heating unit-side decompression unit.

[0360] Therefore, in the single hot gas air heating mode of the present embodiment, even when the outside air temperature Tam is extremely low, the heat generated by the workload of the compressor 11 can be effectively used to heat the ventilation air, and the air in the vehicle cabin can be heated, as in the first embodiment. (d-2) Cooling hot gas air heating mode

[0361] In the cooling hot gas air heating mode, the controller 60 operates the low-temperature side pump 41 to exhibit the predetermined reference pumping power, compared to the single hot gas air heating mode. Other operations are similar to those in the single hot gas air heating mode.

[0362] Therefore, in the cooling hot gas air heating mode, the heat generated by the workload of the compressor 11 can be effectively used to heat the ventilation air, and the air in the vehicle cabin can be heated. The battery 70 can be cooled as in the first embodiment. (e-1) Single hot gas dehumidification and air heating mode

[0363] In the heat pump cycle 10a in the single hot gas dehumidification and air heating mode, the control device 60 brings the air heating expansion valve 14a to the fully closed state, brings the air cooling expansion valve 14b to the throttled state, brings the cooling expansion valve 14c to the throttled state, and brings the bypass-side flow rate control valve 14d to the throttled state. In addition, the control device 60 closes the air heating ON / OFF valve 22b, opens the first inlet-port-side ON / OFF valve 22c, and closes the second inlet-port-side ON / OFF valve 22d.

[0364] Therefore, in the heat pump cycle 10a, in the single hot-gas dehumidification and air heating mode, the refrigerant discharged from the compressor 11 circulates similarly to the cooling hot-gas air heating mode. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the first three-way joint 12a, the radiator 20, the receiver 24, the air-cooling expansion valve 14b in the throttled state, the indoor evaporator 18, and the suction port of the compressor 11 in this order.

[0365] The control device 60 also controls the throttle opening of the cooling expansion valve 14c such that the superheat degree SH of the intake refrigerant approaches the reference superheat degree KSH. The control device 60 appropriately controls the operations of other control target devices as in the first embodiment. Therefore, in the hot gas dehumidification and air heating mode, the cooling expansion valve 14c serves as the heating unit-side decompression unit, as in the first embodiment.

[0366] Therefore, in the single hot gas dehumidification and air heating mode of the present embodiment, the ventilation air is heated with higher heating efficiency than in the series dehumidification and air heating mode, and the air in the vehicle cabin can be dehumidified and heated as in the first embodiment. (e-2) Cooling hot gas dehumidification and air heating mode

[0367] In the cooling hot gas dehumidification and air heating mode, the controller 60 operates the low-temperature side pump 41 to exhibit the predetermined reference pumping capacity, compared to the single hot gas dehumidification and air heating mode. Other operations are similar to those in the single hot gas dehumidification and air heating mode.

[0368] Therefore, in the cooling hot gas dehumidification and air heating mode, the ventilation air is heated with a higher heating power than in the series dehumidification and air heating mode, and the air in the vehicle cabin can be dehumidified and heated as in the single hot gas dehumidification and air heating mode. The battery 70 can be cooled as in the first embodiment. (f-1) Single hot gas row dehumidification and air heating mode

[0369] In the heat pump cycle 10a in the single hot gas series dehumidification and air heating mode, the control device 60 places the air heating expansion valve 14a in the throttled state, the air cooling expansion valve 14b in the throttled state, the cooling expansion valve 14c in the throttled state, and the bypass-side flow rate control valve 14d in the throttled state. In addition, the control device 60 closes the air heating ON / OFF valve 22b, closes the first inlet-port-side ON / OFF valve 22c, and opens the second inlet-port-side ON / OFF valve 22d.

[0370] Therefore, in the heat pump cycle 10a, in the single hot-gas series dehumidification and air heating mode, the refrigerant discharged from the compressor 11 circulates similarly to the cooling series dehumidification and air heating mode. At the same time, the refrigerant circuit is switched to a refrigerant circuit in which the refrigerant discharged from the compressor 11 circulates through the first three-way joint 12a, the bypass-side flow rate control valve 14d in the throttled state arranged in the bypass passage 21c, the sixth three-way joint 12f, and the suction port of the compressor 11 in this order.

[0371] The control device 60 also controls the throttle opening of the cooling expansion valve 14c so that the superheat degree SH of the intake refrigerant approaches the reference superheat degree KSH. The control device 60 appropriately controls the operations of other control target devices as in the first embodiment. Therefore, in the hot gas series dehumidification and air heating mode, the air heating expansion valve 14a and the cooling expansion valve 14c serve as the heating unit-side decompression unit, as in the first embodiment.

[0372] Therefore, in the single hot gas series dehumidification and air heating mode of the present embodiment, the ventilation air is heated with higher heating performance than in the series dehumidification and air heating mode, and the air in the vehicle cabin can be dehumidified and heated as in the first embodiment. (f-2) Cooling hot gas series dehumidification and air heating mode

[0373] In the cooling hot gas row dehumidification and air heating mode, the controller 60 operates the low-temperature side pump 41 to exhibit the predetermined reference pumping capacity, compared to the single hot gas row dehumidification and air heating mode. Other operations are similar to those in the single hot gas row dehumidification and air heating mode.

[0374] Therefore, in the cooling hot gas row dehumidification and air heating mode, the ventilation air is heated with a higher heating power than in the row dehumidification and air heating mode, and the air in the vehicle cabin can be dehumidified and heated as in the single hot gas row dehumidification and air heating mode. The battery 70 can be cooled similarly to the cooling hot gas row dehumidification and air heating mode of the first embodiment. Furthermore, the compressor 11 can be protected by executing the upper limit opening control and the opening increase control.

[0375] As described above, the vehicle air conditioner 1a of the present embodiment can also achieve similar effects to the first embodiment. That is, by switching the operation mode, comfortable air conditioning in the vehicle cabin and appropriate temperature control of the battery 70, which is an on-vehicle device, can be performed.

[0376] Furthermore, since the suction-side flow path length L1 is equal to or longer than the expansion distance Lv, similar effects to those of the first embodiment can be achieved. That is, even in the heat pump cycle device where refrigerants with different enthalpies are mixed and sucked into the compressor, the compressor 11 can be protected without deteriorating productivity.

[0377] The present disclosure is not limited to the embodiments described above and may be modified in various ways as follows without departing from the gist of the present disclosure.

[0378] In the above embodiments, the example in which the heat pump cycle device according to the present disclosure is applied to an air conditioner has been described, but the application target of the heat pump cycle device is not limited to the air conditioner. For example, it can be applied to a water heater that heats domestic water or the like as a heating object. The heating object is not limited to a fluid. For example, the heating object can be a heat-generating device in which a passage for a heat medium is formed for circulating a high-temperature side heat medium for heating or the like.

[0379] The configuration of the heat pump cycle device according to the present disclosure is not limited to the configurations disclosed in the above-described embodiments.

[0380] In the above embodiments, the example in which the sixth three-way junction 12f is formed in such a manner that the junction angle θv is approximately 90° was used as the junction portion, but the junction angle θv is not limited. The junction angle θv may be set to a value that makes it possible to reduce the average flow velocity Uv at the junction MX without unnecessarily increasing the pressure loss generated in the refrigerant flowing through the sixth three-way junction 12f. Specifically, the angle may be set to a value equal to or greater than 45° and equal to or less than 135°.

[0381] In the above embodiments, the example in which the length of the suction-side passage 21d from the outlet port of the sixth three-way junction 12f to the suction port of the compressor 11 is defined as the suction-side flow path length L1 was described. Alternatively, the length of the refrigerant passage from the junction MX to the suction port of the compressor 11 may be defined as the suction-side flow path length L1.

[0382] In the above embodiments, the example using the second check valve 16b was described, but an evaporation pressure regulating valve may also be used instead of the second check valve 16b. The evaporation pressure regulating valve is a variable throttling mechanism that maintains a refrigerant evaporation temperature in the indoor evaporator 18 at a predetermined temperature (e.g., a temperature at which the indoor evaporator 18 can be suppressed) or higher.

[0383] As the evaporation pressure regulating valve, a variable throttle mechanism having a mechanical mechanism that increases the valve opening as the refrigerant pressure on the outlet port side of the indoor evaporator 18 increases may be used. As the evaporation pressure regulating valve, a variable throttle mechanism having an electrical mechanism similar to that of the air-heating expansion valve 14a or the like may be used.

[0384] In the fourth embodiment described above, the example in which the accumulator 23 is arranged in the suction-side passage 21d was described, but it is not limited thereto. A silencer may be arranged in the suction-side passage 21d as long as the effect of reducing the average flow velocity Uv at the junction MX can be achieved. The silencer forms a buffer space for reducing the pressure pulsation of the suction refrigerant.

[0385] A subcooling expansion valve that decompresses the refrigerant flowing into the receiver 24 may be arranged in the heat pump cycle 10a of the fifth embodiment described above. Specifically, a fixed throttle may be used as the subcooling expansion valve, or a variable throttle mechanism may be used. The subcooling expansion valve is preferably arranged in a refrigerant flow path from the outlet port of the seventh three-way junction 12g to the inlet port of the receiver 24.

[0386] Accordingly, the degree of subcooling of the refrigerant flowing out of the indoor condenser 131 can be increased to increase the refrigerant pressure (ie, the discharge refrigerant pressure Pd) in the indoor condenser 131. This can improve the heating performance of the ventilation air in the indoor condenser 131.

[0387] In the fifth embodiment described above, the example in which the sixth three-way junction 12f, which is a joining portion, is arranged in the refrigerant flow path from the outlet port of the cooling expansion valve 14c to the inlet port of the refrigerant passage in the radiator 20 was described, but it is not limited thereto. In the heat pump cycle 10a, the sixth three-way junction 12f may be arranged in the refrigerant flow path from the outlet of the refrigerant passage in the radiator 20 to the suction port of the compressor 11.

[0388] Furthermore, the control sensor group connected to the input side of the control device 60 is not limited to the detection unit disclosed in the above-described embodiments. Various detection units can be added as needed.

[0389] In the above embodiments, the use of R1234yf as the refrigerant of the heat pump cycles 10 and 10a was described, but this is not limited to this. For example, R134a, R600a, R410A, R404A, R32, R407C, and the like can be used. Alternatively, a mixed refrigerant obtained by mixing a plurality of types of these refrigerants or the like can be used. Furthermore, carbon dioxide can be used as the refrigerant, and a supercritical refrigerant cycle in which the high-pressure side refrigerant pressure is equal to or higher than the critical pressure of the refrigerant can be configured.

[0390] The example of using an aqueous ethylene glycol solution as the low-temperature side heat medium and the high-temperature side heat medium of the above-described embodiments has been described, but it is not limited thereto. For example, a solution containing dimethylpolysiloxane, nanofluid, or the like, an antifreeze liquid, an aqueous alcohol-based liquid refrigerant, or the like, or a liquid medium containing oil or the like can be used as the high-temperature side and low-temperature side heat medium.

[0391] The control mode of the heat pump cycle device according to the present disclosure is not limited to the control modes disclosed in the above-described embodiments.

[0392] In the above embodiments, the vehicle air conditioners 1 and 1a capable of performing various operation modes have been described, but the heat pump cycle device according to the present disclosure may not be capable of performing all of the above-described operation modes.

[0393] The heat pump cycle device according to the present disclosure can achieve similar effects to the above-described embodiments as long as the heat pump cycle device can execute at least one of the hot gas air heating mode, the hot gas defrosting and air heating mode, or the hot gas series dehumidification and air heating mode. That is, even in the heat pump cycle device in which refrigerants with different enthalpies are mixed and drawn into the compressor, the compressor 11 can be protected without affecting productivity.

[0394] Furthermore, it may be possible to implement other operating modes. For example, it may be possible to implement a device cooling mode in which only the battery 70 is cooled without performing air conditioning of the vehicle cabin. Specifically, when the device cooling mode is implemented, the control device 60 switches the refrigerant circuit of the heat pump cycle 10 in the same manner as in the cooling-and-air cooling mode to bring the air-cooling expansion valve 14b into the fully closed state. Furthermore, the control device 60 may stop the interior fan 52.

[0395] Furthermore, for example, when the battery 70 has an extremely low temperature, a warm-up hot gas air heating mode may be performed to warm the battery 70. Specifically, when the battery 70 has an extremely low temperature, the control device 60 may warm the battery 70 by performing a similar operation to the cooling hot gas air heating mode.

[0396] Moreover, the control mode of the control device 60 in the hot gas air heating mode is not limited to the examples disclosed in the above embodiments.

[0397] For example, the control device 60 may control the refrigerant discharge capacity of the compressor 11 so that the discharge refrigerant pressure Pd approaches the target high pressure PDO. In this case, the operation of the bypass-side flow rate control valve 14d may be controlled so that the suction refrigerant pressure Ps approaches the first target low pressure PSO1. The operation of the cooling expansion valve 14c may be controlled so that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH.

[0398] For example, the control device 60 may control the throttle opening of the cooling expansion valve 14c so that the discharge refrigerant pressure Pd approaches the target high pressure PDO. In this case, the control device 60 may control the refrigerant discharge capacity of the compressor 11 so that the suction refrigerant pressure Ps approaches the first target low pressure PSO1. The operation of the bypass-side flow rate control valve 14d may be controlled so that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH.

[0399] That is, in the hot-gas air heating mode, the control device 60 can control the operation of at least one of the compressor 11, the heating-unit-side decompression unit, or the bypass-side air flow rate control unit in such a way that the superheat degree SH of the intake refrigerant approaches the reference superheat degree KSH. The same applies to the hot-gas dehumidification and air heating mode and the hot-gas series dehumidification and air heating mode.

[0400] In the hot gas air heating mode, the control device 60 may control the operation of at least one of the compressor 11, the heating unit-side decompression unit, or the bypass-side flow rate control unit in such a manner that the dryness Rx of the suction refrigerant approaches the reference dryness KRx.

[0401] Specifically, the heat pump cycle device includes a dryness detection unit for detecting or estimating the dryness Rx of the intake refrigerant. The length of the flow path from the outlet port of the sixth three-way junction 12f to the dryness detection unit attachment portion is set to be equal to or longer than the expansion distance Lv. The control device 60 can control the operation of at least one of the compressor 11, the heating-unit-side decompression unit, or the bypass-side flow rate control unit in such a manner that the dryness Rx of the intake refrigerant approaches the reference dryness KRx.

[0402] At this time, the reference dryness KRx may be set in such a manner that the suction refrigerant is a two-phase gas-liquid refrigerant appropriately containing a liquid-phase refrigerant in which refrigerant oil is dissolved.

[0403] This allows the refrigerant to be detected by the dryness detection unit to be made homogeneous. The control device 60 can accurately determine or estimate the dryness Rx of the intake refrigerant and appropriately control the operations of various control target devices.

[0404] Moreover, the control mode in which the dryness Rx of the suction refrigerant is controlled to approach the reference dryness KRx is effective in that a decrease in the dryness of the suction refrigerant due to a liquid level loss and an insufficient return amount of the refrigerant oil to the compressor 11 can be prevented in the heat pump cycle device having the accumulator 23 as in the third embodiment.

[0405] The means disclosed in the individual embodiments can be suitably combined within an executable range.

[0406] For example, the indoor condenser 131 described in the fifth embodiment can be used as the heating unit of the vehicle air conditioner 1 of the first to fourth embodiments. Likewise, the water-refrigerant heat exchanger 13 described in the first embodiment and the high-temperature side heat medium circuit 30 described in the first embodiment can be used as the heating unit of the vehicle air conditioner 1a of the fifth embodiment.

[0407] In the vehicle air conditioner 1a of the fifth embodiment, the example in which the sixth three-way junction 12f, which is a joining portion, is disposed in the refrigerant flow path from the outlet port of the cooling expansion valve 14c to the inlet port of the refrigerant passage in the radiator 20 was described, but the sixth three-way junction may be disposed as in the first embodiment. That is, in the vehicle air conditioner 1a of the fifth embodiment, the sixth three-way junction 12f may be disposed as the joining portion in the refrigerant flow path from the refrigerant outlet port of the radiator 20 to the suction port of the compressor 11.

[0408] Although the present disclosure has been described according to examples, it should be understood that the present disclosure is not limited to the examples and structures. The present disclosure also includes various modifications and modifications within an equivalent range. Furthermore, various combinations and modes, as well as other combinations and modes including only one element, multiple elements, or fewer elements, are also within the scope and spirit of the present disclosure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2022-024884

[0001] JP-2021-156567-A

[0007]

Claims

[1] Heat pump cycle device with: a compressor (11) designed to compress and discharge a refrigerant; a branch portion (12a) configured to branch off a flow of the refrigerant discharged from the compressor; a heating unit (13, 30, 131) configured to heat a heating object using a refrigerant branched at the branch portion as a heat source; a heating unit-side decompression unit (14a, 14b, 14c) designed to decompress the refrigerant flowing out of the heating unit; a bypass passage (21c) through which another refrigerant branched at the branch portion flows; a bypass-side flow rate control unit (14d) configured to control a flow rate of the refrigerant flowing through the bypass passage; and a joining portion (12f) configured to join a flow of heating unit-side refrigerant flowing out of the heating unit-side decompression unit and a flow of bypass-side refrigerant flowing out of the bypass-side flow rate control unit and to cause a joined refrigerant to flow to a suction port of the compressor, wherein when a length of a suction-side flow path (21d) from an outlet port of the merging section to the suction port of the compressor is defined as a suction-side flow path length L1, the suction-side flow path length L1 is equal to or longer than a relaxation distance Lv, the relaxation distance Lv is defined by the following formula 1, Lv=ρL×dp218μg×Uv in Formula 1, ρL is a density of droplets which are particles of a liquid-phase refrigerant contained in the refrigerant at a junction MX of the heating unit-side refrigerant and the bypass-side refrigerant in the junction portion, dp is an average diameter of the droplets, µg is a viscosity of a gas-phase refrigerant contained in the refrigerant at the junction MX, and Uv is an average flow velocity of the droplets and the gas-phase refrigerant at the junction MX. [2] Heat pump cycle device according to claim 1, further comprising a suction refrigerant temperature detection unit (62f) designed to detect a temperature of a suction refrigerant to be sucked into the compressor, wherein when a length of a flow path from an outlet port of the merging portion to an attachment portion of the suction refrigerant temperature detection unit is defined as a detection unit flow path length L2, the detection unit flow path length L2 is equal to or longer than the relaxation distance Lv. [3] The heat pump cycle device according to claim 1 or 2, further comprising a low-pressure side gas-liquid separation unit (23) arranged in the suction-side flow path and separating the refrigerant flowing through the suction-side flow path into gas and liquid. [4] The heat pump cycle device according to any one of claims 1 to 3, further comprising a heat exchanger (20) disposed in the suction-side flow path for exchanging heat between the refrigerant and a heat medium. [5] The heat pump cycle device according to any one of claims 1 to 4, wherein a refrigerant passage inside the merging portion is configured to cause a flow direction of the heating unit-side refrigerant immediately before merging and a flow direction of the bypass-side refrigerant immediately before merging to cross each other.

Images