Heat pump cycle device

Abstract

To provide a heat pump cycle device capable of exhibiting sufficiently high heating capacity without increasing the pressure of a low pressure refrigerant.SOLUTION: An air conditioner 1 for vehicle which is a heat pump cycle device includes: a compressor 11; a first three-way joint 12a for branching the flow of a high pressure refrigerant discharged from a discharge port 11c of the compressor 11; a water refrigerant heat exchanger 13 for forming a heating part; a high stage side expansion valve 14c; a gas-liquid separator 15b for hot gas; an expansion valve 14e for cooling: a bypass passage 21f; a bypass side flow rate adjustment valve 14f; and a seventh three-way joint 12g for merging the flow of the refrigerant which has flowed out from the bypass side flow rate adjustment valve 14f and the flow of the refrigerant which has flowed out from the expansion valve 14e for cooling. At the time of a multiple-stage hot gas heating mode for heating blowing air by the heating part, a gas-phase refrigerant separated by the gas-liquid separator 15b for hot gas is guided to an intermediate pressure suction port 11b side of the compressor 11, and the refrigerant is guided to a low pressure suction port 11a of the compressor 11 from the seventh three-way joint 12g.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a heat pump cycle apparatus that heats an object to be heated by using heat generated by the compression work of a compressor. [Background technology]

[0002] Patent Document 1 discloses a heat pump cycle device that is applied to a vehicle air conditioner and heats the air to be blown into the vehicle cabin. The heat pump cycle device of Patent Document 1 operates in a hot gas heating mode under operating conditions that make it difficult to absorb heat from the outside air to heat the air to be blown, such as when the outside air temperature is low.

[0003] In the heat pump cycle device of Patent Document 1, in hot gas heating mode, a refrigerant circuit is switched to flow a portion of the high-pressure refrigerant discharged from the compressor into a heating unit. The heating unit heats the air using the high-pressure refrigerant as a heat source. Furthermore, the refrigerant flowing out of the heating unit and the remaining high-pressure refrigerant discharged from the compressor are decompressed in different decompression units, mixed, and then switched to a refrigerant circuit that draws the refrigerant into the compressor.

[0004] As a result, in the heat pump cycle device of Patent Document 1, in hot gas heating mode, the heat pump air, which is the object to be heated, is heated by using the heat generated by the compression work of the compressor, rather than using heat absorbed from the outside air, thereby heating the vehicle cabin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-156567 Summary of the Invention [Problem to be solved by the invention]

[0006] In the hot gas heating mode of Patent Document 1, the compression workload of the compressor needs to be increased to improve the heating capacity of the heating section. Furthermore, in order to increase the compression workload of the compressor, it is effective to increase the suction pressure of the low-pressure refrigerant drawn into the compressor, thereby increasing the density of the low-pressure refrigerant drawn into the compressor.

[0007] However, in the heat pump cycle device of Patent Document 1, low-pressure components such as an indoor evaporator and a chiller are connected to the compressor suction port. Therefore, the suction refrigerant pressure cannot be increased above the upper limit pressure determined by the pressure resistance of the low-pressure components. Therefore, in the hot gas heating mode of Patent Document 1, there is a limit to how much the heating capacity of the heating unit can be improved.

[0008] In view of the above, an object of the present invention is to provide a heat pump cycle device that heats an object to be heated using heat generated by the compression work of a compressor, and that can exhibit sufficiently high heating capacity without increasing the pressure of a low-pressure refrigerant. [Means for solving the problem]

[0009] To achieve the above object, the heat pump cycle apparatus according to claim 1 includes a compressor (11), an upstream branch section (12a), a heating section (13, 30), a high-stage pressure reduction section (14c), a hot gas gas-liquid separation section (15b), a low-stage pressure reduction section (14d, 14e), a bypass passage (21f), a bypass-side flow rate adjustment section (14f), and a confluence section (12g).

[0010] The compressor compresses low-pressure refrigerant drawn through the low-pressure suction port (11a) and discharges it from the discharge port (11c), and also merges intermediate-pressure refrigerant drawn through the intermediate-pressure suction port (11b) with the low-pressure refrigerant in the compression process. The upstream branching section branches the flow of high-pressure refrigerant discharged from the discharge port. The heating section heats an object to be heated using one of the high-pressure refrigerants branched at the upstream branching section as a heat source. The high-stage pressure reducing section reduces the pressure of the refrigerant flowing out from the heating section. The hot gas gas-liquid separation section separates the refrigerant flowing out from the high-stage pressure reducing section into gas and liquid phases. The low-stage pressure reducing section reduces the pressure of the liquid-phase refrigerant separated by the hot gas gas-liquid separation section. The bypass passage guides the other high-pressure refrigerant branched at the upstream branching section to the low-pressure suction port side. The bypass-side flow rate adjusting section adjusts the flow rate of refrigerant flowing through the bypass passage. The confluence section merges the flow of refrigerant flowing out from the bypass-side flow rate adjustment section and the flow of refrigerant flowing out from the low-stage side pressure reduction section.

[0011] During the multi-stage hot gas heating mode in which the object to be heated is heated in the heating section, the gas phase refrigerant separated in the hot gas gas-liquid separation section is led to the intermediate pressure suction port side, and the refrigerant flowing out from the confluence section is led to the low pressure suction port side.

[0012] According to this, in the multistage hot gas heating mode, the refrigerant flow having a relatively high enthalpy flowing out from the bypass-side flow rate adjuster (14f) and the refrigerant flow having a relatively low enthalpy flowing out from the low-stage side pressure reducer (14d, 14e) are merged at the junction (12g) and directed to the low-pressure suction port (11a) of the compressor (11). Therefore, the refrigerant drawn into the low-pressure suction port (11a) of the compressor (11) can be maintained in an appropriate state, and the cycle can be operated stably.

[0013] Therefore, in the multi-stage hot gas heating mode, the object to be heated can be stably heated in the heating section (13, 30) using the heat generated by the compression work of the compressor (11) without using the heat absorbed from the outside air.

[0014] Furthermore, in the multistage hot gas heating mode, the gas phase refrigerant separated in the hot gas gas-liquid separator (15b) is drawn into the intermediate-pressure suction port (11b), thereby increasing the compression work of the compressor (11) without increasing the pressure of the low-pressure refrigerant, and thus allowing the heating sections (13, 30) to exhibit a sufficiently high heating capacity without increasing the pressure of the low-pressure refrigerant.

[0015] The heat pump cycle apparatus according to claim 2 includes a compressor (11), an upstream branch section (12a), a heating section (13, 30), a downstream branch section (12m), a high-stage pressure reduction section (14c), an internal heat exchange section (24), a low-stage pressure reduction section (14d, 14e), a bypass passage (21f), a bypass-side flow rate adjustment section (14f), and a confluence section (12g).

[0016] The compressor compresses low-pressure refrigerant drawn through the low-pressure suction port (11a) and discharges it from the discharge port (11c), while merging intermediate-pressure refrigerant drawn through the intermediate-pressure suction port (11b) with the low-pressure refrigerant in the compression process. The upstream branching section branches the flow of high-pressure refrigerant discharged from the discharge port. The heating section heats an object to be heated using one of the high-pressure refrigerants branched at the upstream branching section as a heat source. The downstream branching section branches the flow of refrigerant flowing out from the heating section. The high-stage pressure reducing section reduces the pressure of one of the refrigerants branched at the downstream branching section. The internal heat exchange section exchanges heat between the refrigerant flowing out from the high-stage pressure reducing section and the other refrigerant branched at the downstream branching section. The low-stage pressure reducing section reduces the pressure of the other refrigerant branched at the downstream branching section and flowing out of the internal heat exchanger. The bypass passage guides the other high-pressure refrigerant branched at the upstream branching section to the low-pressure suction port. The bypass-side flow rate adjusting unit adjusts the flow rate of the refrigerant flowing through the bypass passage. The confluence unit merges the flow of the refrigerant flowing out of the bypass-side flow rate adjusting unit with the flow of the refrigerant flowing out of the low-stage pressure reducing unit.

[0017] During the multi-stage hot gas heating mode in which the heating object is heated in the heating section, the refrigerant heated in the internal heat exchange section is directed to the intermediate pressure intake port side, and the refrigerant flowing out from the confluence section is directed to the low pressure intake port side.

[0018] According to this, in the multistage hot gas heating mode, the refrigerant flow having a relatively high enthalpy flowing out from the bypass-side flow rate adjuster (14f) and the refrigerant flow having a relatively low enthalpy flowing out from the low-stage pressure reducer (14d, 14e) are joined together at the joining section (12g) and guided to the low-pressure suction port (11a) of the compressor (11). Therefore, the refrigerant drawn into the low-pressure suction port (11a) of the compressor (11) can be maintained in an appropriate state, and the cycle can be operated stably.

[0019] Therefore, in the multi-stage hot gas heating mode, the object to be heated can be stably heated in the heating section (13, 30) using the heat generated by the compression work of the compressor (11) without using the heat absorbed from the outside air.

[0020] Furthermore, in the multistage hot gas heating mode, the refrigerant heated in the internal heat exchange section (24) is drawn into the intermediate-pressure suction port (11b), thereby increasing the compression work of the compressor (11) without increasing the pressure of the low-pressure refrigerant. As a result, the heating sections (13, 30) can exhibit a sufficiently high heating capacity without increasing the pressure of the low-pressure refrigerant.

[0021] The symbols in parentheses for each means described in this section and in the claims are examples showing the correspondence with the specific means described in the embodiments to be described later. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic overall configuration diagram of a vehicle air conditioner according to a first embodiment. [Figure 2] 1 is a schematic configuration diagram of an indoor air conditioning unit according to a first embodiment. [Figure 3] 2 is a block diagram showing an electric control unit of the vehicle air conditioner of the first embodiment. FIG. [Figure 4] 1 is a schematic overall configuration diagram showing the flow of refrigerant in a single-stage hot gas heating mode of a heat pump cycle of a first embodiment. FIG. [Figure 5]FIG. 3 is a Mollier diagram showing changes in the state of a refrigerant in a single-stage hot gas heating mode of the heat pump cycle of the first embodiment. [Figure 6] 1 is a schematic overall configuration diagram showing the flow of refrigerant and the like in a multistage hot gas heating mode of a heat pump cycle of a first embodiment. FIG. [Figure 7] FIG. 3 is a Mollier diagram showing changes in the state of a refrigerant in a multistage hot gas heating mode of the heat pump cycle of the first embodiment. [Figure 8] FIG. 5 is a schematic diagram illustrating the overall configuration of a vehicle air conditioner according to a second embodiment. [Figure 9] FIG. 10 is a schematic overall configuration diagram of a vehicle air conditioner according to a third embodiment. [Figure 10] FIG. 10 is a schematic diagram illustrating the overall configuration of a vehicle air conditioner according to a fourth embodiment. [Figure 11] FIG. 10 is a schematic overall configuration diagram showing the flow of refrigerant and the like in a single-stage hot gas heating mode of a heat pump cycle of a fourth embodiment. [Figure 12] FIG. 10 is a schematic overall configuration diagram showing the flow of refrigerant and the like in a multistage hot gas heating mode of a heat pump cycle of a fourth embodiment. [Figure 13] FIG. 10 is a Mollier diagram showing changes in the state of refrigerant in a multistage hot gas heating mode of a heat pump cycle of a fourth embodiment. [Figure 14] FIG. 10 is a schematic overall configuration diagram of a vehicle air conditioner according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, several embodiments for carrying out the present invention will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment will be assigned the same reference numerals, and duplicate explanations may be omitted. In each embodiment, when only a part of the configuration is described, other previously described embodiments may be applied to the other parts of the configuration. In addition to combinations of parts that are specifically specified as being combinable in each embodiment, it is also possible to partially combine embodiments even if not specified, as long as there is no particular problem with the combination.

[0024] (First embodiment) A first embodiment of a heat pump cycle device according to the present invention will be described with reference to Figures 1 to 7. In this embodiment, the heat pump cycle device according to the present invention is applied to a vehicle air conditioner 1 mounted on an electric vehicle. An electric vehicle is a vehicle that obtains driving power for traveling from an electric motor. The vehicle air conditioner 1 conditions the air inside the vehicle cabin, which is the space to be air-conditioned, and also adjusts the temperature of on-board equipment. Therefore, the vehicle air conditioner 1 can be called an air conditioner with an on-board equipment temperature adjustment function, or an on-board equipment temperature adjustment device with an air conditioning function.

[0025] Specifically, the vehicle air conditioner 1 adjusts the temperature of a battery 70 as an in-vehicle device. The battery 70 is a secondary battery that stores power to be supplied to a plurality of electrically operated in-vehicle devices. The battery 70 is an assembled battery formed by electrically connecting a plurality of stacked battery cells in series or parallel. The battery cells in this embodiment are lithium-ion batteries.

[0026] The battery 70 is a heat-generating device that generates heat during operation (i.e., during charging and discharging). The output of the battery 70 is likely to decrease at low temperatures, and deterioration is likely to progress at high temperatures. For this reason, the temperature of the battery 70 needs to be maintained within an appropriate temperature range (in this embodiment, 15°C or higher and 55°C or lower). Therefore, in the electric vehicle of this embodiment, the temperature of the battery 70 is adjusted using the vehicle air conditioner 1.

[0027] The vehicle air conditioner 1 is configured to be able to switch between various operating modes in order to air-condition the vehicle interior and adjust the temperature of the battery 70. 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 interior air conditioning unit 50, a control device 60, etc.

[0028] First, the heat pump cycle 10 will be described. The heat pump cycle 10 forms a vapor compression refrigeration cycle that adjusts the temperatures of the air blown into the vehicle cabin, the high-temperature heat medium circulating through the high-temperature heat medium circuit 30, and the low-temperature heat medium circulating through the low-temperature heat medium circuit 40. The heat pump cycle 10 is configured so that the circuit configuration of the refrigerant circuit can be switched depending on the operation mode of the vehicle air conditioner 1.

[0029] The heat pump cycle 10 employs an HFO refrigerant (specifically, R1234yf) as a refrigerant. The heat pump cycle 10 constitutes a subcritical refrigeration cycle in which the pressure of the high-pressure side refrigerant does not exceed the critical pressure of the refrigerant. Refrigerant oil is mixed into the refrigerant to lubricate the compressor 11. In this embodiment, PAG oil, which is compatible with liquid-phase refrigerants, is employed as the refrigerant oil. A portion of the refrigerant oil circulates through the heat pump cycle 10 together with the refrigerant.

[0030] The compressor 11 draws in, compresses, and discharges refrigerant in the heat pump cycle 10. The compressor 11 is a two-stage boost type electric compressor in which a low-stage compression mechanism and a high-stage compression mechanism, each with a fixed discharge capacity, are rotated and driven by a common electric motor. The rotation speed (i.e., refrigerant discharge capacity) of the compressor 11 is controlled by a control signal output from a control device 60, which will be described later.

[0031] The compressor 11 has a housing that forms a space for accommodating a low-pressure compression mechanism, a high-pressure compression mechanism, an electric motor, etc. The housing is formed with a low-pressure suction port 11a, an intermediate-pressure suction port 11b, and a discharge port 11c.

[0032] The low-pressure suction port 11a is an opening hole for drawing low-pressure refrigerant from the outside of the housing into the low-stage compression mechanism. The intermediate-pressure suction port 11b is an opening hole for allowing intermediate-pressure refrigerant to flow from the outside to the inside of the housing and join with refrigerant in the process of being compressed from low pressure to high pressure. The intermediate-pressure suction port 11b is connected inside the housing to the discharge port side of the low-stage compression mechanism and the suction port side of the high-stage compression mechanism. The discharge port 11c is an opening hole for discharging high-pressure refrigerant discharged from the high-stage compression mechanism to the outside of the housing.

[0033] The compressor 11 is disposed in a drive unit compartment formed at the front side of the vehicle interior. The drive unit compartment forms a space in which at least some of the devices used to generate and adjust the driving force for running the vehicle (for example, an electric motor for running) are disposed.

[0034] The inlet side of a first three-way joint 12a is connected to the discharge port 11c of the compressor 11. The first three-way joint 12a has three inlet and outlet ports that communicate with each other. The first three-way joint 12a can be a joint formed by joining multiple pipes or a joint formed by providing multiple refrigerant passages in a metal block or a resin block.

[0035] Furthermore, the heat pump cycle 10 of this embodiment includes a second three-way joint 12b to a ninth three-way joint 12i, as will be described later. The second three-way joint 12b to the ninth three-way joint 12i have the same basic configuration as the first three-way joint 12a. The three-way joints described in the embodiments below also have the same basic configuration as the first three-way joint 12a.

[0036] These three-way joints function as a branching section that branches the refrigerant flow when one of the three inlet / outlet ports is used as an inlet and the other two are used as outlet ports. Furthermore, when two of the three inlet / outlet ports are used as inlet ports and the other is used as an outlet port, the three-way joints function as a merging section that merges the refrigerant flows. The first three-way joint 12a functions as an upstream branching section that branches the high-pressure refrigerant flow discharged from the discharge port 11c of the compressor 11.

[0037] One outlet of the first three-way joint 12a is connected to the inlet side of the refrigerant passage of the water-refrigerant heat exchanger 13. The other outlet of the first three-way joint 12a is connected to one inlet side of the seventh three-way joint 12g.

[0038] The refrigerant passage extending from the other outlet of the first three-way joint 12a to one inlet of the seventh three-way joint 12g is a bypass passage 21f that guides the other high-pressure refrigerant branched at the first three-way joint 12a to the low-pressure suction port 11a side. A bypass-side flow control valve 14f is disposed in the bypass passage 21f.

[0039] The bypass-side flow rate adjustment valve 14f is a bypass-passage-side pressure reduction unit that reduces the pressure of the refrigerant flowing out from the other outlet of the first three-way joint 12a (i.e., the other refrigerant branched at the first three-way joint 12a) in a multistage hot gas heating mode, etc., which will be described later. Furthermore, the bypass-side flow rate adjustment valve 14f is a bypass-side flow rate adjustment unit that adjusts the flow rate (mass flow rate) of the refrigerant flowing through the bypass passage 21f.

[0040] The bypass-side flow rate adjustment valve 14f is an electric variable throttle mechanism having a valve element that changes the throttle opening and an electric actuator that displaces the valve element. A stepping motor or a brushless motor can be used as the electric actuator. The operation of the bypass-side flow rate adjustment valve 14f is controlled by a control signal output from the control device 60.

[0041] The bypass-side flow control valve 14f has a full-open function that functions simply as a refrigerant passage by fully opening the valve and exerts almost no refrigerant pressure reduction or flow rate adjustment action, and a full-close function that closes the refrigerant passage by fully closing the valve.

[0042] Furthermore, as will be described later, the heat pump cycle 10 of this embodiment includes an outdoor unit high-stage side expansion valve 14a, an outdoor unit low-stage side expansion valve 14b, a high-stage side expansion valve 14c, a cooling expansion valve 14d, and a cooling expansion valve 14e. The outdoor unit high-stage side expansion valve 14a, the outdoor unit low-stage side expansion valve 14b, the high-stage side expansion valve 14c, the cooling expansion valve 14d, and the cooling expansion valve 14e have the same basic configuration as the bypass-side flow control valve 14f.

[0043] Furthermore, the basic configurations of the expansion valve and the flow rate adjustment valve described in the embodiments below are also similar to those of the bypass-side flow rate adjustment valve 14f.

[0044] The outdoor unit high-stage side expansion valve 14a, the outdoor unit low-stage side expansion valve 14b, the high-stage side expansion valve 14c, the cooling expansion valve 14d, the cooling expansion valve 14e, and the bypass-side flow control valve 14f can switch the refrigerant circuit through which the refrigerant circulates by performing the fully closing function described above. Therefore, the outdoor unit high-stage side expansion valve 14a, the outdoor unit low-stage side expansion valve 14b, the high-stage side expansion valve 14c, the cooling expansion valve 14d, the cooling expansion valve 14e, and the bypass-side flow control valve 14f also function as a refrigerant circuit switching unit that switches the refrigerant circuit.

[0045] Of course, the outdoor unit high-stage expansion valve 14a, the outdoor unit low-stage expansion valve 14b, the high-stage expansion valve 14c, the cooling expansion valve 14d, the cooling expansion valve 14e, and the bypass-side flow control valve 14f may be formed by combining a variable throttle mechanism that does not have a full-closing function with an on-off valve that opens and closes the refrigerant passage. In this case, each on-off valve serves as a refrigerant circuit switching unit.

[0046] The water-refrigerant heat exchanger 13 is a heat exchange unit that exchanges heat between the high-pressure refrigerant flowing out from one outlet of the first three-way joint 12a (i.e., one of the high-pressure refrigerant branches at the first three-way joint 12a) and the high-temperature side heat medium circulating in the high-temperature side heat medium circuit 30. The water-refrigerant heat exchanger 13 heats the high-temperature side heat medium by dissipating heat from the high-pressure refrigerant to the high-temperature side heat medium.

[0047] The inlet side of the second three-way joint 12b is connected to the outlet of the refrigerant passage of the water-refrigerant heat exchanger 13. The inlet side of the outdoor unit high-stage side expansion valve 14a is connected to one outlet of the second three-way joint 12b. The other outlet of the second three-way joint 12b is connected to one inlet side of the fifth three-way joint 12e. The refrigerant passage extending from the other outlet of the second three-way joint 12b to one inlet of the fifth three-way joint 12e is the high-pressure side passage 21a.

[0048] A high-pressure side on-off valve 22a is disposed in the high-pressure side passage 21a. The high-pressure side on-off valve 22a is an on-off valve that opens and closes the high-pressure side passage 21a. The high-pressure side 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.

[0049] Furthermore, the heat pump cycle 10 of this embodiment includes a heating on-off valve 22b, an intermediate-pressure side on-off valve 22c, and a low-pressure side on-off valve 22d, as will be described later. The heating on-off valve 22b, the intermediate-pressure side on-off valve 22c, and the low-pressure side on-off valve 22d have the same basic configuration as the high-pressure side on-off valve 22a. In addition, the basic configuration of the on-off valves described in the embodiments below is also the same as the high-pressure side on-off valve 22a.

[0050] The high-pressure side on-off valve 22a, the heating on-off valve 22b, the intermediate-pressure side on-off valve 22c, and the low-pressure side on-off valve 22d can switch the refrigerant circuit by opening and closing the refrigerant passage. Therefore, the high-pressure side on-off valve 22a, the heating on-off valve 22b, the intermediate-pressure side on-off valve 22c, and the low-pressure side on-off valve 22d are refrigerant circuit switching units that switch the refrigerant circuit.

[0051] The outdoor unit high-stage expansion valve 14a is an outdoor unit high-stage pressure reducing section that reduces the pressure of the refrigerant flowing out of the water-refrigerant heat exchanger 13 during an outside air heat absorption heating mode, which will be described later. Furthermore, the outdoor unit high-stage expansion valve 14a is an outdoor unit high-stage flow rate adjusting section that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the heating gas-liquid separator 15a.

[0052] The outlet of the outdoor unit high-stage expansion valve 14a is connected to the inlet side of a heating gas-liquid separator 15a. The heating gas-liquid separator 15a is a heating gas-liquid separator that separates the refrigerant flowing out from the outdoor unit high-stage expansion valve 14a into gas and liquid.

[0053] In this embodiment, a centrifugal separation type (cyclone separator type) gas-liquid separation unit that separates the gas and liquid phase refrigerant by the action of centrifugal force is used as the heating gas-liquid separator 15a. Furthermore, in this embodiment, a gas-liquid separation unit with a relatively small internal volume that discharges the separated liquid phase refrigerant without storing it inside is used as the heating gas-liquid separator 15a.

[0054] A gas phase refrigerant outlet of the heating gas-liquid separator 15a is connected to one inlet side of the third three-way joint 12c. The refrigerant passage extending from the gas phase refrigerant outlet of the heating gas-liquid separator 15a to one inlet side of the third three-way joint 12c is a heating intermediate pressure passage 21b. A heating on-off valve 22b is disposed in the heating intermediate pressure passage 21b. The heating on-off valve 22b opens and closes the heating intermediate pressure passage 21b.

[0055] The outlet of the third three-way joint 12c is connected to the intermediate pressure suction port 11b side of the compressor 11. The refrigerant passage extending from the outlet of the third three-way joint 12c to the intermediate pressure suction port 11b of the compressor 11 is an intermediate pressure passage 21c. An intermediate pressure side on-off valve 22c is disposed in the intermediate pressure passage 21c. The intermediate pressure side on-off valve 22c is an intermediate pressure side on-off unit that opens and closes the intermediate pressure passage 21c.

[0056] The liquid-phase refrigerant outlet of the heating gas-liquid separator 15a is connected to the inlet side of the outdoor unit low-stage expansion valve 14b. The outdoor unit low-stage expansion valve 14b is an outdoor unit low-stage pressure reduction unit that reduces the pressure of the refrigerant flowing out of the heating gas-liquid separator 15a in the outdoor air heat absorption heating mode. Furthermore, the outdoor unit low-stage expansion valve 14b is an outdoor unit low-stage flow rate adjustment unit that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the outdoor heat exchanger 16.

[0057] The outlet of the outdoor unit low-stage expansion valve 14b is connected to the refrigerant inlet side of the outdoor heat exchanger 16. The outdoor heat exchanger 16 is an outdoor heat exchanger that exchanges heat between the refrigerant decompressed by the outdoor unit low-stage expansion valve 14b and outside air blown by an outside air fan (not shown). The outdoor heat exchanger 16 is located on the front side of the drive unit compartment. Therefore, when the vehicle is traveling, the traveling air that flows into the drive unit compartment through the grill can be directed against the outdoor heat exchanger 16.

[0058] The outdoor heat exchanger 16 functions as a refrigerant heat radiating section that radiates heat from the refrigerant to the outside air in a cooling mode (to be described later), and as a refrigerant heat absorbing section that absorbs heat from the outside air into the refrigerant in an outside air heat absorption heating mode.

[0059] An inlet side of a fourth three-way joint 12d is connected to a refrigerant outlet of the outdoor heat exchanger 16. One outlet side of the fourth three-way joint 12d is connected to the other inlet side of the fifth three-way joint 12e via a first check valve 17a. The first check valve 17a allows the refrigerant to flow from the fourth three-way joint 12d side to the fifth three-way joint 12e side and prevents the refrigerant from flowing from the fifth three-way joint 12e side to the fourth three-way joint 12d side.

[0060] The other outlet of the fourth three-way joint 12d is connected to one inlet side of the ninth three-way joint 12i. The refrigerant passage extending from the other outlet of the fourth three-way joint 12d to one inlet of the ninth three-way joint 12i is a low-pressure side passage 21d. A low-pressure side on-off valve 22d is disposed in the low-pressure side passage 21d. The low-pressure side on-off valve 22d opens and closes the low-pressure side passage 21d.

[0061] A high-stage expansion valve 14c is disposed at the outlet of the fifth three-way joint 12e. The high-stage expansion valve 14c is a high-stage pressure reducing unit that reduces the pressure of the refrigerant flowing out of the water-refrigerant heat exchanger 13 in a cooling mode and a multistage hot gas heating mode, which will be described later. Furthermore, the high-stage expansion valve 14c is a high-stage flow rate adjusting unit that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the hot gas gas-liquid separator 15b.

[0062] The outlet of the high-stage expansion valve 14c is connected to the inlet side of a hot gas gas-liquid separator 15b. The hot gas gas-liquid separator 15b is a hot gas gas-liquid separator that separates the refrigerant flowing out from the high-stage expansion valve 14c into gas and liquid. The hot gas gas-liquid separator 15b can be a gas-liquid separator similar to the heating gas-liquid separator 15a.

[0063] The gas-phase refrigerant outlet of hot gas gas-liquid separator 15b is connected to the other inlet side of third three-way joint 12c. A hot gas intermediate pressure passage 21e is a refrigerant passage extending from the gas-phase refrigerant outlet of hot gas gas-liquid separator 15b to the other inlet side of third three-way joint 12c. A second check valve 17b is disposed in hot gas intermediate pressure passage 21e.

[0064] The second check valve 17b allows the refrigerant to flow from the hot gas gas-liquid separator 15b side to the third three-way joint 12c side, and prohibits the refrigerant from flowing from the third three-way joint 12c side to the hot gas gas-liquid separator 15b side.

[0065] The liquid-phase refrigerant outlet of the hot gas gas-liquid separator 15b is connected to the inlet side of a sixth three-way joint 12f. One outlet of the sixth three-way joint 12f is connected to the refrigerant inlet side of the indoor evaporator 18. The other outlet of the sixth three-way joint 12f is connected to the refrigerant inlet side of the chiller 20.

[0066] A cooling expansion valve 14d is disposed in the refrigerant passage extending from one outlet of the sixth three-way joint 12f to the refrigerant inlet of the indoor evaporator 18. The cooling expansion valve 14d is an indoor pressure reducing unit that reduces the pressure of the refrigerant flowing out from one outlet of the sixth three-way joint 12f in a cooling mode, which will be described later. Furthermore, the cooling expansion valve 14d is an indoor flow rate adjusting unit that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the indoor evaporator 18.

[0067] The cooling expansion valve 14d is included in a low-stage side decompression section that decompresses the liquid-phase refrigerant separated in the hot gas gas-liquid separator 15b.

[0068] The interior evaporator 18 is disposed 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 exchanger that exchanges heat between a low-pressure refrigerant decompressed by the cooling expansion valve 14d and the blown air blown into the vehicle interior from the interior blower 52. The interior evaporator 18 is an interior evaporation section that cools the blown air by evaporating the low-pressure refrigerant and exerting a heat absorption effect.

[0069] Therefore, the interior evaporator 18 is a cooling section that evaporates the refrigerant decompressed by the cooling expansion valve 14e, and cools the blown air that is the object to be cooled.

[0070] One inlet side of an eighth three-way joint 12h is connected to the refrigerant outlet of the indoor evaporator 18. An evaporation pressure regulating valve 19 is arranged in the refrigerant passage leading from the refrigerant outlet of the indoor evaporator 18 to one inlet side of the eighth three-way joint 12h.

[0071] The evaporation pressure regulating valve 19 is a variable throttle mechanism that maintains the refrigerant evaporation temperature in the indoor evaporator 18 at a temperature (1°C in this embodiment) or higher that can suppress frost formation on the indoor evaporator 18. The evaporation pressure regulating valve 19 is configured with a mechanical mechanism that increases the valve opening degree as the refrigerant pressure on the refrigerant outlet side of the indoor evaporator 18 increases.

[0072] A cooling expansion valve 14e is disposed in the refrigerant passage extending from the other outlet of the sixth three-way joint 12f to the refrigerant inlet of the chiller 20. The cooling expansion valve 14e is a cooling-side pressure reducing unit that reduces the pressure of the refrigerant flowing out from the other outlet of the sixth three-way joint 12f during a cooling mode, which will be described later. The cooling expansion valve 14e is also a cooling-side flow rate adjusting unit that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the chiller 20.

[0073] The cooling expansion valve 14e is included in a low-stage side decompression section that decompresses the liquid-phase refrigerant separated in the hot gas gas-liquid separator 15b.

[0074] The chiller 20 is a low-temperature side heat exchange unit that exchanges heat between the low-pressure refrigerant decompressed by the cooling expansion valve 14e and the low-temperature side heat medium circulating in the low-temperature side heat medium circuit 40. The chiller 20 is a cooling evaporation unit that cools the low-temperature side heat medium by evaporating the low-pressure refrigerant and exerting a heat absorption effect.

[0075] The other inlet side of seventh three-way joint 12g is connected to the refrigerant outlet of chiller 20. The other inlet side of eighth three-way joint 12h is connected to the outlet of seventh three-way joint 12g. The other inlet side of ninth three-way joint 12i is connected to the outlet of eighth three-way joint 12h.

[0076] The outlet of the ninth three-way joint 12i is connected to the inlet side of the accumulator 23. The accumulator 23 is a low-pressure liquid storage section that separates the refrigerant that flows into it into gas and liquid phases and stores the separated liquid-phase refrigerant as surplus refrigerant for the cycle. The gas-phase refrigerant outlet of the accumulator 23 is connected to the suction port side of the compressor 11.

[0077] As is clear from the above description, seventh three-way joint 12g joins the refrigerant flowing out from cooling expansion valve 14e and the refrigerant flowing out from bypass-side flow control valve 14f in the single-stage hot gas heating mode and the multi-stage hot gas heating mode, which will be described later. Furthermore, seventh three-way joint 12g serves as a joining section that allows the joined refrigerant to flow into the suction port side of compressor 11.

[0078] Next, the high-temperature side heat medium circuit 30 will be described. The high-temperature side heat medium circuit 30 is a heat medium circulation circuit that circulates the high-temperature side heat medium. In this embodiment, an ethylene glycol aqueous 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, etc.

[0079] The high-temperature side pump 31 is a high-temperature side heat medium pumping unit that pumps the high-temperature side heat medium that has flowed out from the heat medium passage of the water-refrigerant heat exchanger 13 to the heat medium inlet side of the heater core 32. The high-temperature side pump 31 is an electric pump whose rotation speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 60.

[0080] The heater core 32 is a heating heat exchanger that heats the blown air by exchanging heat between the high-temperature side heat medium heated in the water-refrigerant heat exchanger 13 and the blown air that has passed through the indoor evaporator 18. The heater core 32 is disposed in an air conditioning case 51 of the indoor air conditioning unit 50. The heat medium outlet of the heater core 32 is connected to the inlet side of the heat medium passage of the water-refrigerant heat exchanger 13.

[0081] Therefore, the water-refrigerant heat exchanger 13 and each component of the high-temperature side heat medium circuit 30 in this embodiment are heating units that heat the blown air, which is the object to be heated, using one of the high-pressure refrigerants branched at the first three-way joint 12a as a heat source.

[0082] 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 this embodiment, the same type of fluid as the high-temperature side heat medium is used as the low-temperature side heat medium. The low-temperature side heat medium circuit 40 is connected to a low-temperature side pump 41, a coolant passage 70a of the battery 70, a heat medium passage of the chiller 20, etc.

[0083] 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 from the cooling water passage 70a of the battery 70 to the inlet side of the heat medium passage of the chiller 20. The basic configuration of the low-temperature side pump 41 is similar to that of the high-temperature side pump 31. The outlet side of the heat medium passage of the chiller 20 is connected to the inlet side of the cooling water passage 70a of the battery 70.

[0084] The coolant passage 70a of the battery 70 is a coolant passage formed to cool the battery 70 by circulating a low-temperature heat medium cooled by the chiller 20. The coolant passage 70a is formed inside a battery case that houses a plurality of stacked battery cells.

[0085] The cooling water passage 70a is configured with multiple passages connected in parallel inside the battery case. This allows the cooling water passage 70a to cool all battery cells evenly. The outlet of the cooling water passage 70a is connected to the suction port side of the low-temperature side pump 41.

[0086] Therefore, the chiller 20 and the components of the low-temperature side heat medium circuit 40 are a cooling unit that evaporates the refrigerant decompressed by the cooling expansion valve 14e to cool the battery 70, which is an object to be cooled.

[0087] Next, the interior air conditioning unit 50 will be described with reference to Figure 2. The interior air conditioning unit 50 is a unit that integrates multiple components to blow out air adjusted to an appropriate temperature to appropriate locations within the vehicle cabin for air conditioning. The interior air conditioning unit 50 is located inside the instrument panel at the front of the vehicle cabin.

[0088] The indoor air conditioning unit 50 is formed by accommodating an indoor blower 52, an indoor evaporator 18, a heater core 32, etc. in an air conditioning case 51 that forms an air passage for blown air. The air conditioning case 51 is made of a resin (for example, polypropylene) that has a certain degree of elasticity and excellent strength.

[0089] An inside / outside air switching device 53 is disposed on the most upstream side of the blown air flow of the air conditioning case 51. The inside / outside air switching device 53 switches between introducing inside air (i.e., air inside the vehicle cabin) and outside air (i.e., air outside the vehicle cabin) 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.

[0090] An interior blower 52 is disposed downstream of the inside / outside air switching device 53 in the flow of blown air. The interior blower 52 is a blower that blows air taken in through the inside / outside air switching device 53 toward the vehicle interior. The rotation speed (i.e., blowing capacity) of the interior blower 52 is controlled by a control voltage output from the control device 60.

[0091] The interior evaporator 18 and the heater core 32 are disposed downstream in the flow of air blown by the interior blower 52. The interior evaporator 18 is disposed upstream in the flow of air blown from the heater core 32. A cool air bypass passage 55 is formed in the air conditioning case 51, which allows the air blown after passing through the interior evaporator 18 to bypass the heater core 32.

[0092] An air mix door 54 is disposed downstream of the interior evaporator 18 in the air conditioning case 51 in the direction of the blown air flow, and upstream of the heater core 32 and the cool air bypass passage 55 in the direction of the blown air flow.

[0093] The air mix door 54 adjusts the ratio of the volume of the blown air passing through the heater core 32 to the volume of the blown air passing through the cool air bypass passage 55, among the blown air that has passed through the interior evaporator 18. The operation of the actuator for driving the air mix door 54 is controlled by a control signal output from the control device 60.

[0094] A mixing space 56 is disposed downstream of the heater core 32 and the cold air bypass passage 55 in the flow direction of the blown air. The mixing space 56 is a space where the blown air heated by the heater core 32 and the blown air that has passed through the cold air bypass passage 55 and has not been heated are mixed.

[0095] Therefore, in the interior air conditioning unit 50, by adjusting the opening degree of the air mix door 54, it is possible to adjust the temperature of the blown air (that is, the conditioned air) that is mixed in the mixing space 56 and blown into the vehicle interior.

[0096] A plurality of openings (not shown) for blowing conditioned air toward various locations in the vehicle cabin are formed at the most downstream portion of the airflow of the air-conditioning case 51. A blowout mode door (not shown) for opening and closing each of the openings is disposed in each opening. The operation of the actuator for driving the blowout mode door is controlled by a control signal output from the control device 60.

[0097] Therefore, in the interior air conditioning unit 50, by switching the opening holes that the blow-out mode door opens and closes, conditioned air that has been adjusted to an appropriate temperature can be blown out to an appropriate location in the vehicle interior.

[0098] Next, the electrical control unit of this embodiment will be described using the block diagram of Figure 3. The control device 60 has a well-known microcomputer including a CPU, ROM, RAM, etc., and its peripheral circuits. The control device 60 performs various calculations and processes based on control programs stored in the ROM. Then, the control device 60 controls the operation of various control target devices connected to the output side based on the results of the calculations and processes.

[0099] A group of control sensors, such as an inside air temperature sensor 61a, an outside air temperature sensor 61b, a solar radiation sensor 61c, a discharge refrigerant temperature and pressure sensor 62a, a high-pressure side refrigerant temperature and pressure sensor 62b, an outdoor unit side refrigerant temperature and pressure sensor 62c, an evaporator side refrigerant temperature and pressure sensor 62d, a chiller side refrigerant temperature and pressure sensor 62e, an evaporator 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, and an air conditioning air temperature sensor 65, are connected to the input side of the control device 60.

[0100] The inside air temperature sensor 61a is an inside air temperature detector that detects the temperature inside the vehicle cabin (inside air temperature) Tr. The outside air temperature sensor 61b is an outside air temperature detector that detects the temperature outside the vehicle cabin (outside air temperature) Tam. The solar radiation sensor 61c is an solar radiation amount detector that detects the amount of solar radiation As irradiating into the vehicle cabin.

[0101] The discharge refrigerant temperature and pressure sensor 62 a is a discharge refrigerant temperature and pressure detection unit that detects the discharge refrigerant temperature Td and the discharge refrigerant pressure Pd of the discharge refrigerant discharged from the compressor 11 .

[0102] The high-pressure side refrigerant temperature and pressure sensor 62b is a high-pressure side refrigerant temperature and pressure detection unit that detects the high-pressure side refrigerant temperature T1 and high-pressure side refrigerant pressure P1 of the refrigerant flowing out from the water-refrigerant heat exchanger 13.

[0103] The outdoor unit side refrigerant temperature and pressure sensor 62c is an outdoor unit side refrigerant temperature and pressure detection unit that detects the outdoor unit side refrigerant temperature T2 and outdoor unit side refrigerant pressure P2 of the refrigerant flowing out from the outdoor heat exchanger 16.

[0104] The evaporator-side refrigerant temperature and pressure sensor 62d is an evaporator-side refrigerant temperature and pressure detection unit that detects the evaporator-side refrigerant temperature Te and evaporator-side refrigerant pressure Pe of the refrigerant flowing out from the interior evaporator .

[0105] The chiller-side refrigerant temperature and pressure sensor 62e is a chiller-side refrigerant temperature and pressure detection unit that detects the chiller-side refrigerant temperature Tc and chiller-side refrigerant pressure Pc of the refrigerant flowing out from the refrigerant passage of the chiller 20. Specifically, the chiller-side refrigerant temperature and pressure sensor 62e of the present embodiment detects the temperature and pressure of the refrigerant that flows out from the seventh three-way joint 12g and before it enters the other inlet of the eighth three-way joint 12h.

[0106] In this embodiment, a detection unit in which a pressure detection unit and a temperature detection unit are integrated is used as the refrigerant temperature and pressure sensor, but of course, a pressure detection unit and a temperature detection unit that are each configured as separate units may also be used.

[0107] The evaporator temperature sensor 62f is an evaporator temperature detection unit that detects the refrigerant evaporation temperature (evaporator temperature) Tefin in the interior evaporator 18. Specifically, the evaporator temperature sensor 62f of the present embodiment detects the heat exchange fin temperature of the interior evaporator 18.

[0108] The high-temperature-side heat medium temperature sensor 63a is a high-temperature-side heat medium temperature detector 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 detector that detects a low-temperature-side heat medium temperature TWL, which is the temperature of the low-temperature-side heat medium flowing into the coolant passage 70a of the battery 70.

[0109] The battery temperature sensor 64 is a battery temperature detection unit that detects the battery temperature TB, which is the temperature of the battery 70. The battery temperature sensor 64 has multiple temperature sensors and detects the temperature at multiple locations on the battery 70. This allows the control device 60 to detect the temperature difference and temperature distribution among the battery cells that make up the battery 70. Furthermore, the average value of the detection values ​​of the multiple temperature sensors is used as the battery temperature TB.

[0110] The air conditioning air temperature sensor 65 detects the blown air temperature TAV, which is the temperature of the blown air blown into the vehicle interior from the mixing space 56. Therefore, the air conditioning air temperature sensor 65 is an object temperature detection unit that detects the object temperature of the blown air, which is the object to be heated.

[0111] Furthermore, an operation panel 69 located near the instrument panel at the front of the vehicle interior is connected to the input side of the control device 60, as shown in Fig. 3. Operation signals are input to the control device 60 from various operation switches provided on the operation panel 69.

[0112] The various operation switches provided on the operation panel 69 specifically include an auto switch, an air conditioner switch, an air volume setting switch, a temperature setting switch, and the like.

[0113] The auto switch is an automatic control setting unit that sets or cancels automatic control operation of the vehicle air conditioner 1. The air conditioner switch is a cooling request unit that requests cooling of the blown air by the interior evaporator 18. 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 the set temperature Tset in the vehicle interior.

[0114] The control device 60 of this embodiment is an integrated unit that controls various control target devices connected to its output side. Therefore, the configuration (i.e., hardware and software) that controls the operation of each control target device forms a control unit that controls the operation of each control target device.

[0115] For example, in the control device 60, the component that controls the refrigerant discharge capacity of the compressor 11 is a discharge capacity control unit 60a. The component that controls the operation of the refrigerant circuit switching unit is a refrigerant circuit control unit 60b. The refrigerant circuit control unit 60b has an intermediate pressure on / off control unit 60c that controls the operation of the intermediate pressure side on / off valve 22c. The refrigerant circuit control unit 60b has a high stage side pressure reduction control unit 60d that controls the operation of the high stage side expansion valve 14c.

[0116] Furthermore, in the control device 60, the component that determines the target blowout temperature TAO, which is the target temperature of the air blown into the vehicle compartment, is the target temperature determination unit 60e.

[0117] Next, the operation of the vehicle air conditioner 1 of this embodiment with the above configuration will be described. The vehicle air conditioner 1 switches between various operation modes to condition the air in the vehicle compartment and adjust the temperature of the battery 70. The operation mode is switched by executing a control program stored in advance in the control device 60.

[0118] The control program is executed not only when the start switch (so-called ignition switch) of the vehicle system is turned on and the vehicle system is running, but also when the battery 70 is being charged from an external power source, etc. The control program conditions the air inside the vehicle cabin when the auto switch is turned on.

[0119] The control program reads detection signals from the group of control sensors described above and operation signals from operation panel 69. Then, target temperature determination unit 60e determines target blow-out temperature TAO based on the read detection signals and operation signals.

[0120] Target temperature determination unit 60e calculates target blow-out temperature TAO using the following formula F1. TAO=Kset×Tset-Kr×Tr-Kam×Tam-Ks×As+C…(F1) Tset is the set temperature inside the vehicle cabin set by the temperature setting switch. Tr is the inside air temperature detected by the inside air temperature sensor 61a. Tam is the outside air temperature detected by the outside air temperature sensor 61b. As is the amount of solar radiation detected by the solar radiation sensor 61c. Kset, Kr, Kam, and Ks are control gains, and C is a correction constant.

[0121] Furthermore, the control program selects an operation mode based on the detection signal, the operation signal, the target blowout temperature TAO, etc., and controls the operation of various controlled devices according to the selected operation mode.

[0122] Thereafter, until the termination condition of the control program is met, the control routine of reading the above-mentioned detection signals and operation signals, determining the target blow-out temperature TAO, selecting an operation mode, and controlling the operation of various controlled devices according to the selected operation mode is repeated at each predetermined control cycle. The detailed operation of each operation mode is described below.

[0123] (a) Cooling mode The cooling mode is an operating mode in which cooled air is blown into the passenger compartment to cool the interior of the vehicle. The cooling mode is likely to be selected when the auto switch and air conditioner switch are on, the outside air temperature Tam is relatively high, or the target outlet temperature TAO is relatively low.

[0124] The cooling modes include a single cooling mode in which the vehicle cabin is cooled without cooling the battery 70, and a cooled / cooled mode in which the vehicle cabin is cooled while cooling the battery 70. In the control program of this embodiment, when the battery temperature TB detected by the battery temperature sensor 64 becomes equal to or higher than a predetermined reference upper limit temperature KTBH, an operation mode for cooling the battery 70 is executed.

[0125] (a-1) Single cooling mode In the heat pump cycle 10 in the cooling-only mode, the control device 60 sets the outdoor unit high-stage expansion valve 14a to a fully open state, the outdoor unit low-stage expansion valve 14b to a fully open state, the high-stage expansion valve 14c to a throttled state that exerts a pressure-reducing effect, the cooling expansion valve 14d to a throttled state, the cooling expansion valve 14e to a fully closed state, and the bypass-side flow control valve 14f to a fully closed state.

[0126] Furthermore, the control device 60 closes the high pressure side on-off valve 22a, closes the heating on-off valve 22b, opens the intermediate pressure side on-off valve 22c, and closes the low pressure side on-off valve 22d.

[0127] Therefore, in the heat pump cycle 10 in the cooling-only mode, the refrigerant discharged from the discharge port 11c of the compressor 11 flows in the following order: water-refrigerant heat exchanger 13, the fully-open outdoor unit high-stage expansion valve 14a, the heating gas-liquid separator 15a, the fully-open outdoor unit low-stage expansion valve 14b, the outdoor heat exchanger 16, the high-stage expansion valve 14c, and the hot gas gas-liquid separator 15b. The gas refrigerant separated in the hot gas gas-liquid separator 15b flows in the following order: the hot gas intermediate-pressure passage 21e, the intermediate-pressure passage 21c, and the intermediate-pressure suction port 11b of the compressor 11. At the same time, the refrigerant circuit is switched to one in which the liquid refrigerant separated in the hot gas gas-liquid separator 15b flows in the following order: the cooling expansion valve 14d, the indoor evaporator 18, the evaporation pressure control valve 19, the accumulator 23, and the low-pressure suction port 11a of the compressor 11.

[0128] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the evaporator temperature Tefin detected by the evaporator temperature sensor 62f approaches the target evaporator temperature TEO.

[0129] The target evaporator temperature TEO is determined based on the target air outlet temperature TAO by referring to a control map for the cooling mode stored in advance in the control device 60. The control map determines the target evaporator temperature TEO so that it increases as the target air outlet temperature TAO increases. The target evaporator temperature TEO is determined to a value (at least 1°C or higher in this embodiment) that can suppress frost formation on the interior evaporator 18.

[0130] The control device 60 also controls the throttle opening of the high-stage expansion valve 14c so that the degree of subcooling SC2 of the refrigerant flowing out of the outdoor heat exchanger 16 approaches a predetermined reference degree of subcooling KSC2. The degree of subcooling SC2 of the refrigerant flowing out of the outdoor heat exchanger 16 can be determined from the outdoor unit side refrigerant temperature T2 and the outdoor unit side refrigerant pressure P2 detected by the outdoor unit side refrigerant temperature and pressure sensor 62c.

[0131] Furthermore, the control device 60 controls the throttle opening of the cooling expansion valve 14d so that it becomes a predetermined reference opening for the cooling mode.

[0132] In the high-temperature side heat medium circuit 30 in the single cooling mode, the control device 60 controls the operation of the high-temperature side pump 31 so as to achieve a predetermined reference pumping capacity. Therefore, in the high-temperature side heat medium circuit 30 in the single cooling mode, the high-temperature side heat medium pumped from the high-temperature side pump 31 circulates through the heater core 32, the heat medium passage of the water-refrigerant heat exchanger 13, and the suction port of the high-temperature side pump 31 in this order.

[0133] Furthermore, in the indoor air conditioning unit 50 in the single cooling mode, the control device 60 controls the air blowing capacity of the indoor blower 52 based on the target blowing temperature TAO by referring to a control map stored in advance in the control device 60. The control map determines the maximum air blowing volume of the indoor blower 52 in the extremely low temperature range (maximum cooling range) and the extremely high temperature range (maximum heating range) of the target blowing temperature TAO, and decreases the air blowing volume as the temperature approaches the intermediate temperature range.

[0134] The control device 60 also adjusts the opening degree of the air mix door 54 so that the blown air temperature TAV detected by the air conditioning air temperature sensor 65 approaches the target blown air temperature TAO. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0135] Therefore, in the heat pump cycle 10 in the cooling only mode, the water-refrigerant heat exchanger 13 and the outdoor heat exchanger 16 function as condensers that condense the refrigerant by dissipating heat, and the indoor evaporator 18 functions as an evaporator that evaporates the refrigerant, forming a two-stage pressure-boosting vapor compression refrigeration cycle. More specifically, in the heat pump cycle 10 in the cooling only mode, a so-called gas-liquid separation type gas injection cycle is formed.

[0136] In the water-refrigerant heat exchanger 13, the refrigerant dissipates heat to the high-temperature side heat medium, thereby heating the high-temperature side heat medium. In the outdoor heat exchanger 16, the refrigerant dissipates heat to the outside air. In the indoor evaporator 18, the refrigerant absorbs heat from the blown air, thereby cooling the blown air.

[0137] In the high-temperature side heat medium circuit 30 in the single cooling mode, the high-temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32.

[0138] In the interior air conditioning unit 50 in the single cooling mode, the air blown from the interior blower 52 is cooled by the interior evaporator 18. The air cooled by the interior evaporator 18 is heated by the heater core 32 depending on the opening degree of the air mix door 54. Then, the conditioned air whose temperature has been adjusted to approach the target outlet temperature TAO is blown into the vehicle compartment. This achieves cooling of the vehicle compartment.

[0139] (a-2) Cooling mode In the heat pump cycle 10 in the cooling / air-cooling mode, the control device 60 throttles the cooling expansion valve 14e in comparison with the single cooling mode.

[0140] Therefore, in the heat pump cycle 10 in the cooling / cooling mode, the refrigerant discharged from the discharge port 11c of the compressor 11 flows in the same manner as in the single cooling mode. At the same time, the liquid-phase refrigerant separated in the hot gas gas-liquid separator 15b is switched to a refrigerant circuit in which the refrigerant flows through the cooling expansion valve 14e, the chiller 20, the accumulator 23, and the low-pressure suction port 11a of the compressor 11 in this order.

[0141] That is, in the heat pump cycle 10 in the cooling / air-conditioning mode, the indoor evaporator 18 and the chiller 20 are switched to a refrigerant circuit connected in parallel with respect to the flow of the refrigerant.

[0142] Furthermore, the control device 60 controls the throttle opening of the cooling expansion valve 14e so that the throttle opening becomes a predetermined throttle opening for the cooling air-conditioning mode.

[0143] In addition, in the high-temperature side heat medium circuit 30 in the cooling / air-cooling mode, the control device 60 operates the high-temperature side pump 31 in the same manner as in the single cooling mode.

[0144] In addition, in the low-temperature side heat medium circuit 40 in the cooling / cooling mode, the control device 60 controls the operation of the low-temperature side pump 41 so as to exert a predetermined reference pumping capacity. Therefore, in the low-temperature side heat medium circuit 40 in the cooling / cooling mode, the high-temperature side heat medium pumped from the low-temperature side pump 41 circulates through the heat medium passage of the chiller 20, the coolant passage 70a of the battery 70, and the suction port of the low-temperature side pump 41, in that order.

[0145] In addition, in the indoor air conditioning unit 50 in the cooling / air-conditioning mode, the control device 60 controls the blowing capacity of the indoor blower 52 and the opening degree of the air mix door 54, just as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0146] Therefore, in the heat pump cycle 10 in the cooling / air-conditioning mode, the water-refrigerant heat exchanger 13 and the outdoor heat exchanger 16 function as condensers, and the indoor evaporator 18 and the chiller 20 function as evaporators, forming a gas-liquid separation type gas injection cycle.

[0147] In the water-refrigerant heat exchanger 13, the high-temperature side heat medium is heated, as in the single cooling mode. In the outdoor heat exchanger 16, the refrigerant dissipates heat to the outside air. In the indoor evaporator 18, the blown air is cooled, as in the single cooling mode. In the chiller 20, the refrigerant absorbs heat from the low-temperature side heat medium, thereby cooling the low-temperature side heat medium.

[0148] In the high-temperature side heat medium circuit 30 in the cooling / air-cooling mode, the high-temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32, as in the single cooling mode.

[0149] In the low-temperature side heat medium circuit 40 in the cooling / air-cooling mode, the low-temperature side heat medium pumped from the low-temperature side pump 41 flows into the chiller 20. The low-temperature side heat medium that flows into the chiller 20 is cooled by heat exchange with a low-pressure refrigerant. The low-temperature side heat medium cooled in the chiller 20 flows through the coolant passage 70a of the battery 70. This cools the battery 70.

[0150] In addition, in the interior air conditioning unit 50 in the cooling / air-conditioning mode, the temperature-adjusted blown air is blown into the vehicle compartment, thereby cooling the vehicle compartment, as in the single cooling mode.

[0151] (b) Heating mode The heating mode is an operating mode in which heated air is blown into the vehicle cabin to heat the interior. The heating mode is likely to be selected when the auto switch is on, the outside air temperature Tam is relatively low, or the target outlet temperature TAO is relatively high.

[0152] The heating modes include outdoor air endothermic heating mode, single-stage hot gas heating mode, and multi-stage hot gas heating mode. In the heating mode, the target air to be heated is the ventilation air. Therefore, the outdoor air endothermic heating mode, single-stage hot gas heating mode, and multi-stage hot gas heating mode are outdoor air endothermic heating mode, single-stage hot gas heating mode, and multi-stage hot gas heating mode, respectively.

[0153] (b-1) Outdoor air heat absorption heating mode The outdoor air heat absorption heating mode is selected preferentially over the single-stage hot gas heating mode and the multi-stage hot gas heating mode if heat absorbed from the outdoor air can be used as a heat source for heating.

[0154] In the heat pump cycle 10 in the outdoor air heat absorption heating mode, the control device 60 places the outdoor unit high-stage expansion valve 14a in a throttled state, the outdoor unit low-stage expansion valve 14b in a throttled state, the high-stage expansion valve 14c in a fully closed state, the air conditioning expansion valve 14d in a fully closed state, the cooling expansion valve 14e in a fully closed state, and the bypass side flow control valve 14f in a fully closed state.

[0155] Furthermore, the control device 60 closes the high-pressure side on-off valve 22a, opens the heating on-off valve 22b, opens the intermediate-pressure side on-off valve 22c, and opens the low-pressure side on-off valve 22d.

[0156] Therefore, in the heat pump cycle 10 in the outdoor air heat absorption heating mode, the refrigerant discharged from the discharge port 11c of the compressor 11 flows, in this order, through the water-refrigerant heat exchanger 13, the outdoor unit high-stage expansion valve 14a, and the heating gas-liquid separator 15a. Then, the gas-phase refrigerant separated in the heating gas-liquid separator 15a flows, in this order, through the heating intermediate-pressure passage 21b, the intermediate-pressure passage 21c, and the intermediate-pressure suction port 11b of the compressor 11. At the same time, the refrigerant circuit is switched to one in which the liquid-phase refrigerant separated in the heating gas-liquid separator 15a flows, in this order, through the outdoor unit low-stage expansion valve 14b, the outdoor heat exchanger 16, the low-pressure passage 21d, the accumulator 23, and the low-pressure suction port 11a of the compressor 11.

[0157] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the discharge refrigerant pressure Pd detected by the discharge refrigerant temperature / pressure sensor 62a approaches the target high-pressure PDO. The target high-pressure PDO is determined based on the target blow-out temperature TAO by referring to a control map pre-stored in the control device 60. The control map determines the target high-pressure PDO to increase as the target blow-out temperature TAO increases.

[0158] The control device 60 also controls the throttle opening of the outdoor unit high-stage expansion valve 14a so that the degree of subcooling SC1 of the refrigerant flowing out of the water-refrigerant heat exchanger 13 approaches a predetermined reference degree of subcooling KSC1. The degree of subcooling SC1 of the refrigerant flowing out of the water-refrigerant heat exchanger 13 can be determined from the high-pressure side refrigerant temperature T1 and the high-pressure side refrigerant pressure P1 detected by the high-pressure side refrigerant temperature and pressure sensor 62b.

[0159] Furthermore, the control device 60 controls the throttle opening of the outdoor low-stage side expansion valve 14b so that the opening becomes a predetermined reference opening for the heating mode.

[0160] In addition, in the high temperature side heat medium circuit 30 in the outdoor air heat absorption heating mode, the control device 60 operates the high temperature side pump 31 in the same manner as in the single cooling mode.

[0161] In the indoor air conditioning unit 50 in the outdoor air heat absorption heating mode, the control device 60 controls the blowing capacity of the indoor blower 52 and the opening degree of the air mix door 54, just as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0162] Therefore, in the heat pump cycle 10 in the outdoor air heat absorption heating mode, the water-refrigerant heat exchanger 13 functions as a condenser and the outdoor heat exchanger 16 functions as an evaporator, forming a gas-liquid separation type gas injection cycle.

[0163] In the water-refrigerant heat exchanger 13, the high-temperature side heat medium is heated in the same manner as in the single cooling mode. In the outdoor heat exchanger 16, the refrigerant absorbs heat from the outside air.

[0164] In the high-temperature side heat medium circuit 30 in the outdoor air heat absorption heating mode, the high-temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32, as in the single cooling mode.

[0165] In the interior air conditioning unit 50 in the outside air heat absorption heating mode, the air blown from the interior blower 52 passes through the interior evaporator 18. The air that has passed through the interior evaporator 18 is heated by the heater core 32 depending on the opening degree of the air mix door 54. Then, the conditioned air whose temperature has been adjusted to approach the target outlet temperature TAO is blown into the vehicle cabin. This achieves heating of the vehicle cabin.

[0166] (b-2) Single-stage hot gas heating mode The single-stage hot gas heating mode is selected when the heat absorbed from the outside air cannot be used as a heat source for heating, or when it is determined that the heating capacity of the blown air in the heater core 32 is insufficient compared to the target heating capacity while the outside air heat absorption heating mode is being executed.

[0167] In this embodiment, when the rotation speed of the compressor 11 is at its maximum rotation speed and the blown air temperature TAV is lower than the target outlet temperature TAO during the outdoor air heat absorption heating mode, it is determined that the heating capacity is insufficient relative to the target heating capacity. The maximum rotation speed of the compressor 11 can be determined based on the durability of the compressor 11.

[0168] In the heat pump cycle 10 in the single-stage hot gas heating mode, the control device 60 sets the outdoor unit high-stage expansion valve 14a in a fully closed state, the outdoor unit low-stage expansion valve 14b in a fully closed state, the high-stage expansion valve 14c in a fully open state, the air-conditioning expansion valve 14d in a fully closed state, the cooling expansion valve 14e in a throttled state, and the bypass-side flow control valve 14f in a throttled state.

[0169] Furthermore, the control device 60 opens the high pressure side on-off valve 22a, closes the heating on-off valve 22b, closes the intermediate pressure side on-off valve 22c, and closes the low pressure side on-off valve 22d.

[0170] 4, the refrigerant discharged from the discharge port 11c of the compressor 11 circulates in this order through the water-refrigerant heat exchanger 13, the high-pressure passage 21a, the fully open high-stage expansion valve 14c, the hot gas gas-liquid separator 15b, the cooling expansion valve 14e, the chiller 20, the seventh three-way joint 12g, the accumulator 23, and the low-pressure suction port 11a of the compressor 11. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in this order through the bypass-side flow control valve 14f disposed in the bypass passage 21f, the seventh three-way joint 12g, and the low-pressure suction port 11a of the compressor 11.

[0171] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the chiller-side refrigerant pressure Pc detected by the chiller-side refrigerant temperature and pressure sensor 62e approaches a predetermined target low pressure PSO. The target low pressure PSO is set to a value higher than the refrigerant evaporation pressure in the outdoor heat exchanger 16 in the outdoor air heat absorption heating mode.

[0172] Here, the chiller-side refrigerant pressure Pc in the single-stage hot gas heating mode corresponds to the suction refrigerant pressure Ps, which is the pressure of the low-pressure refrigerant drawn into the compressor 11 from the low-pressure suction port 11a. Controlling the suction refrigerant pressure Ps to approach a constant value is effective in stabilizing the discharge flow rate Gr (mass flow rate) of the compressor 11.

[0173] More specifically, by setting the suction refrigerant pressure Ps to a constant pressure of saturated gas-phase refrigerant, it is possible to maintain a constant density of the low-pressure refrigerant drawn into the compressor 11. Therefore, by controlling the suction refrigerant pressure Ps to approach a constant pressure, it becomes easier to stabilize the discharge flow rate Gr of the compressor 11 at the same rotation speed.

[0174] The control device 60 also controls the throttle opening of the bypass-side flow control valve 14f so that the high-low pressure difference ΔP, obtained by subtracting the suction refrigerant pressure Ps from the discharge refrigerant pressure Pd, approaches the target high-low pressure difference ΔP0. The target high-low pressure difference ΔP0 is a value obtained by subtracting the target low pressure P0 from the target high pressure P0, which is determined in the same way as in the outside air heat absorption heating mode.

[0175] Furthermore, the control device 60 controls the throttle opening of the cooling expansion valve 14e so that the degree of subcooling SC1 of the refrigerant flowing out from the water-refrigerant heat exchanger 13 approaches a predetermined reference degree of subcooling KSC1.

[0176] In the single-stage hot gas heating mode, the control device 60 operates the high-temperature side pump 31 in the high-temperature side heat medium circuit 30, as in the single cooling mode. Therefore, in the single-stage hot gas heating mode, the high-temperature side heat medium circulates in the high-temperature side heat medium circuit 30 as shown by the dashed arrows in Figure 4.

[0177] In addition, in the low-temperature side heat medium circuit 40 in the single-stage hot gas heating mode, the control device 60 stops the low-temperature side pump 41.

[0178] In the indoor air conditioning unit 50 in the single-stage hot gas heating mode, the control device 60 controls the blowing capacity of the indoor blower 52 and the opening degree of the air mix door 54, just as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0179] Therefore, in the heat pump cycle 10 in the single-stage hot gas heating mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0180] That is, the flow of high-pressure refrigerant (point a5 in FIG. 5) discharged from the discharge port 11c of the compressor 11 is branched at the first three-way joint 12a. One of the refrigerant branches at the first three-way joint 12a flows into the water-refrigerant heat exchanger 13 and dissipates heat to the high-temperature side heat medium (from point a5 to point b5 in FIG. 5). This heats the high-temperature side heat medium.

[0181] The refrigerant flowing out of the water-refrigerant heat exchanger 13 flows into the high-pressure side passage 21a. Because the high-stage side expansion valve 14c is fully open, the refrigerant that has flowed into the high-pressure side passage 21a flows through the hot gas gas-liquid separator 15b and into the cooling expansion valve 14e, where it is decompressed (from point b5 to point f5 in FIG. 5). The low-pressure refrigerant with a relatively low enthalpy that has flowed out of the cooling expansion valve 14e flows through the chiller 20 into the other inlet of the seventh three-way joint 12g.

[0182] In the single-stage hot gas heating mode, the heating on-off valve 22b and the intermediate pressure side on-off valve 22c are closed, so that the refrigerant does not flow from the gas phase refrigerant outlet of the hot gas gas-liquid separator 15b to the hot gas intermediate pressure passage 21e side. Also, in the single-stage hot gas heating mode, the low temperature side pump 41 is stopped, so that the refrigerant that flows into the chiller 20 does not exchange heat with the low temperature side heat medium.

[0183] The other refrigerant branched at the first three-way joint 12a flows into a bypass passage 21f. The refrigerant flowing into the bypass passage 21f is flow-regulated and decompressed by the bypass-side flow control valve 14f (from point a5 to point h5 in FIG. 5). The low-pressure refrigerant with a relatively high enthalpy decompressed by the bypass-side flow control valve 14f flows into one inlet of the seventh three-way joint 12g.

[0184] At the seventh three-way joint 12g, the flow of low-pressure refrigerant with relatively high enthalpy flowing in from one inlet of the seventh three-way joint 12g and the flow of low-pressure refrigerant with relatively low enthalpy flowing in from the other inlet of the seventh three-way joint 12g join together.

[0185] The refrigerant that joins at the seventh three-way joint 12g flows into the accumulator 23 and is separated into gas and liquid. The gas-phase refrigerant separated in the accumulator 23 (point g5 in FIG. 5) is drawn into the compressor 11 from the low-pressure suction port 11a and compressed. In the single-stage hot gas heating mode, the intermediate-pressure side on-off valve 22c is closed, so the compressor 11 compresses the refrigerant in the same way as a single-stage boost compressor.

[0186] In the high-temperature side heat medium circuit 30 in the single-stage hot gas heating mode, the high-temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32, as in the single cooling mode.

[0187] In addition, in the interior air conditioning unit 50 in the single-stage hot gas heating mode, the interior of the vehicle is heated by blowing temperature-adjusted ventilation air into the vehicle, similar to the outside air heat absorption heating mode.

[0188] (b-3) Multi-stage hot gas heating mode The multi-stage hot gas heating mode is selected when the heat absorbed from the outside air cannot be used as a heat source for heating, or when it is determined that the heating capacity of the blown air in the heater core 32 is insufficient compared to the target heating capacity while the single-stage hot gas heating mode is being executed.

[0189] In this embodiment, when the single-stage hot gas heating mode is being executed and the rotation speed of the compressor 11 is at its maximum rotation speed and the blowing air temperature TAV is lower than the target blowing temperature TAO, it is determined that the heating capacity is insufficient compared to the target heating capacity.

[0190] In the heat pump cycle 10 in the multi-stage hot gas heating mode, the control device 60 places the outdoor unit high-stage expansion valve 14a in a fully closed state, the outdoor unit low-stage expansion valve 14b in a fully closed state, the high-stage expansion valve 14c in a throttled state, the air conditioning expansion valve 14d in a fully closed state, the cooling expansion valve 14e in a throttled state, and the bypass side flow control valve 14f in a throttled state.

[0191] Furthermore, the control device 60 opens the high pressure side on-off valve 22a, closes the heating on-off valve 22b, opens the intermediate pressure side on-off valve 22c, and closes the low pressure side on-off valve 22d.

[0192] 6, in the heat pump cycle 10 in the multistage hot gas heating mode, the refrigerant discharged from the discharge port 11c of the compressor 11 flows through the water-refrigerant heat exchanger 13, the high-pressure side passage 21a, the high-stage side expansion valve 14c, and the hot gas gas-liquid separator 15b in this order. Then, the gas phase refrigerant separated in the hot gas gas-liquid separator 15b flows through the hot gas intermediate pressure passage 21e, the intermediate pressure passage 21c, and the intermediate-pressure suction port 11b of the compressor 11 in this order. Furthermore, the liquid phase refrigerant separated in the hot gas gas-liquid separator 15b flows through the cooling expansion valve 14e, the chiller 20, the seventh three-way joint 12g, the accumulator 23, and the low-pressure suction port 11a of the compressor 11 in this order. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates through the bypass-side flow control valve 14f arranged in the bypass passage 21f, the seventh three-way joint 12g, and the low-pressure intake port 11a of the compressor 11 in that order.

[0193] Furthermore, the control device 60 controls the throttle opening of the high-stage expansion valve 14c. Specifically, when the blowing air temperature TAV can be set to the target outlet temperature TAO by adjusting the opening of the air mix door 54, the control device 60 controls the throttle opening of the high-stage expansion valve 14c so that the degree of subcooling SC1 of the refrigerant flowing out of the water-refrigerant heat exchanger 13 approaches a predetermined reference degree of subcooling KSC1.

[0194] On the other hand, even if the air mix door 54 is displaced to a position where the ventilation passage on the heater core 32 side is fully opened and the cold air bypass passage 55 is fully closed, if the blown air temperature TAV is lower than the target blown air temperature TAO, the throttling opening of the high-stage expansion valve 14c is increased from its current value.

[0195] Furthermore, the control device 60 controls the throttle opening of the cooling expansion valve 14e so that the opening becomes a predetermined reference opening for the multistage hot gas heating mode.

[0196] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 and the throttle opening of the bypass-side flow rate adjustment valve 14f, in the same manner as in the single-stage hot gas heating mode.

[0197] In the high-temperature side heat medium circuit 30 in the multistage hot gas heating mode, the control device 60 operates the high-temperature side pump 31, as in the single cooling mode. Therefore, in the high-temperature side heat medium circuit 30 in the multistage hot gas heating mode, the high-temperature side heat medium circulates as shown by the dashed arrows in Figure 6.

[0198] Furthermore, in the low-temperature side heat medium circuit 40 in the multistage hot gas heating mode, the control device 60 stops the low-temperature side pump 41.

[0199] In the indoor air conditioning unit 50 in the multistage hot gas heating mode, the control device 60 controls the blowing capacity of the indoor blower 52 and the opening degree of the air mix door 54, just as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0200] Therefore, in the heat pump cycle 10 in the multi-stage hot gas heating mode, the state of the refrigerant changes as shown in the Mollier diagram of Fig. 7. In Fig. 7, the state of the refrigerant at the points equivalent in the cycle configuration to the Mollier diagram of Fig. 5, which explains the single-stage hot gas heating mode, is indicated by the same reference characters (alphabet) as in Fig. 5, with only the subscripts (numbers) changed to match the diagram numbers. This also applies to the Mollier diagrams in the following embodiments.

[0201] That is, the flow of high-pressure refrigerant (point a7 in FIG. 7) discharged from the discharge port 11c of the compressor 11 is branched at the first three-way joint 12a. One of the refrigerant branches at the first three-way joint 12a flows into the water-refrigerant heat exchanger 13 and dissipates heat to the high-temperature side heat medium (from point a7 to point b7 in FIG. 7). This heats the high-temperature side heat medium.

[0202] The refrigerant flowing out of the water-refrigerant heat exchanger 13 flows into the high-pressure side passage 21a. The refrigerant flowing into the high-pressure side passage 21a flows into the high-pressure side expansion valve 14c and is reduced in pressure (from point b7 to point c7 in FIG. 7). The intermediate-pressure refrigerant flowing out of the high-pressure side expansion valve 14c flows into the hot gas gas-liquid separator 15b and is separated into gas and liquid (point c7 to point e7, point c7 to point d7 in FIG. 7).

[0203] The gas-phase refrigerant flowing out from the gas-phase refrigerant outlet of hot gas gas-liquid separator 15b (point e7 in FIG. 7) passes through hot gas intermediate pressure passage 21e and intermediate pressure passage 21c, and is drawn into compressor 11 from intermediate pressure suction port 11b. The intermediate-pressure refrigerant drawn through intermediate pressure suction port 11b joins with the refrigerant in the process of being compressed from low pressure to high pressure inside compressor 11 (point i7 in FIG. 7).

[0204] The liquid-phase refrigerant flowing out from the liquid-phase refrigerant outlet of the hot gas gas-liquid separator 15b (point d7 in FIG. 7) flows into the cooling expansion valve 14e and is reduced in pressure (from point d7 to point f7 in FIG. 7). The low-pressure refrigerant with a relatively low enthalpy that flows out from the cooling expansion valve 14e flows through the chiller 20 into the other inlet of the seventh three-way joint 12g.

[0205] In the multistage hot gas heating mode, the low-temperature side pump 41 is stopped, so the refrigerant that has flowed into the chiller 20 does not exchange heat with the low-temperature side heat medium.

[0206] The other refrigerant branched at the first three-way joint 12a flows into the bypass passage 21f, and is decompressed by the bypass-side flow control valve 14f through flow rate adjustment (from point a7 to point h7 in FIG. 7), as in the single-stage hot gas heating mode. The low-pressure refrigerant with a relatively high enthalpy decompressed by the bypass-side flow control valve 14f flows into one inlet of the seventh three-way joint 12g.

[0207] The refrigerant that joins at the seventh three-way joint 12g flows into the accumulator 23 and is separated into gas and liquid. The gas-phase refrigerant (point g7 in FIG. 7) separated in the accumulator 23 is drawn into the compressor 11 from the low-pressure suction port 11a and compressed.

[0208] In the high-temperature side heat medium circuit 30 in the multistage hot gas heating mode, the high-temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32, as in the single cooling mode.

[0209] In addition, in the interior air conditioning unit 50 in the multistage hot gas heating mode, the temperature-adjusted ventilation air is blown into the vehicle compartment, as in the outside air heat absorption heating mode, thereby realizing heating of the vehicle compartment.

[0210] As described above, the vehicle air conditioner 1 of this embodiment can provide comfortable air conditioning for the vehicle interior and appropriately adjust the temperature of the battery 70, which is an on-board device, by switching the operation mode.

[0211] More specifically, the heat pump cycle 10 of this embodiment includes an outdoor unit high-stage expansion valve 14a, a heating gas-liquid separator 15a, an outdoor unit low-stage expansion valve 14b, and an outdoor heat exchanger 16. Therefore, in the vehicle air conditioner 1 of this embodiment, the refrigerant circuit switching unit switches the refrigerant circuit of the heat pump cycle 10, thereby enabling the outdoor air heat absorption heating mode.

[0212] In the outdoor air heat absorption heating mode, heat absorbed from the outdoor air in the outdoor heat exchanger 16 can be used as a heat source for heating. This improves the coefficient of performance (COP) of the cycle, enabling efficient heating.

[0213] The heat pump cycle 10 of this embodiment also includes the intermediate pressure side on-off valve 22c. Therefore, in the vehicle air conditioner 1 of this embodiment, the single-stage hot gas heating mode can be executed by closing the intermediate pressure side on-off valve 22c.

[0214] In the single-stage hot gas heating mode, the flow of refrigerant with a relatively high enthalpy flowing out from the bypass-side flow control valve 14f and the flow of refrigerant with a relatively low enthalpy flowing out from the cooling expansion valve 14e are merged at the seventh three-way joint 12g. This ensures that the low-pressure refrigerant drawn into the low-pressure suction port 11a remains saturated gas-phase refrigerant even if the refrigerant discharge capacity of the compressor 11 is increased, ensuring stable operation of the cycle.

[0215] In other words, in the single-stage hot gas heating mode, the blown air can be stably heated in the heating section using the heat generated by the compression work of the compressor 11, without using heat absorbed from the outside air.

[0216] Furthermore, in the single-stage hot gas heating mode, the intake refrigerant pressure Ps is increased more than in the outdoor air heat absorption heating mode, which increases the density of the low-pressure refrigerant drawn into the low-pressure intake port 11a of the compressor 11 and increases the refrigerant discharge flow rate (mass flow rate) of the compressor 11. As a result, in the single-stage hot gas heating mode, the compression work load of the compressor 11 is increased, and the heating capacity of the blown air in the heating section can be improved more than in the outdoor air heat absorption heating mode.

[0217] In the heat pump cycle 10 of this embodiment, low-pressure components such as the indoor evaporator 18 and the chiller 20 are connected to the low-pressure suction port 11a of the compressor 11. Therefore, in the heat pump cycle 10, the suction refrigerant pressure Ps cannot be increased above an upper limit pressure determined by the pressure resistance of the low-pressure components.

[0218] In other words, in the single-stage hot gas heating mode, even if an attempt is made to improve the heating capacity of the heating section by increasing the suction refrigerant pressure Ps, there is a limit to how much the heating capacity can be improved. Therefore, while it is conceivable to use low-pressure side components with high pressure resistance to improve the heating capacity of the heating section, using low-pressure side components with high pressure resistance would result in an increase in the size and weight of the vehicle air conditioner 1, which would reduce productivity.

[0219] In contrast to this, in the vehicle air conditioner 1 of this embodiment, the multistage hot gas heating mode can be executed by opening the intermediate pressure side on-off valve 22c.

[0220] In the multistage hot gas heating mode, the cycle can be operated stably, just like in the single-stage hot gas heating mode. Therefore, in the multistage hot gas heating mode, the blown air can be stably heated in the heating section using the heat generated by the compression work of the compressor 11, without using heat absorbed from the outside air, just like in the single-stage hot gas heating mode.

[0221] Furthermore, in the multi-stage hot gas heating mode, the gas phase refrigerant separated in the hot gas gas-liquid separator 15b is drawn into the intermediate-pressure suction port 11b of the compressor 11, thereby increasing the compression work of the compressor 11 more than in the single-stage hot gas heating mode. Therefore, the heating section can exhibit a sufficiently high heating capacity without increasing the pressure of the low-pressure refrigerant.

[0222] More specifically, the compression work L1 of the compressor 11 in the single-stage hot gas heating mode is defined by the following formula F2.

[0223] L1=Gs×ΔHs…(F2) 5, Gs is the suction flow rate (mass flow rate) of the low-pressure refrigerant sucked into the compressor 11 from the low-pressure suction port 11a. ΔHs is the increase in enthalpy of the low-pressure refrigerant due to the compression work of the compressor 11.

[0224] Furthermore, the compression work load L2 of the compressor 11 in the multistage hot gas heating mode is defined by the following formula F3.

[0225] L2=Gs×ΔHs+Ginj×ΔHm…(F3) 7, Ginj is the suction flow rate (mass flow rate) of the intermediate-pressure refrigerant sucked into the compressor 11 from the intermediate-pressure suction port 11b. ΔHm is the increase in enthalpy of the intermediate-pressure refrigerant due to the compression work of the compressor 11.

[0226] In the single-stage hot gas heating mode and the multi-stage hot gas heating mode, the suction refrigerant pressure Ps is controlled to approach the target low pressure PSO. Therefore, the suction flow rate Gs of the low-pressure refrigerant in the single-stage hot gas heating mode is equivalent to the suction flow rate Gs of the low-pressure refrigerant in the multi-stage hot gas heating mode.

[0227] Furthermore, in the single-stage hot gas heating mode and the multi-stage hot gas heating mode, the high-low pressure difference ΔP is controlled to approach the target high-low pressure difference ΔP. Therefore, the increase in enthalpy ΔHs of the low-pressure refrigerant in the multi-stage hot gas heating mode shown in Figure 7 is slightly lower than that in the single-stage hot gas heating mode, but is approximately the same as the increase in enthalpy ΔHs of the low-pressure refrigerant in the single-stage hot gas heating mode shown in Figure 5.

[0228] The reason why the enthalpy increase amount ΔHs in the multi-stage hot gas heating mode is lower than the enthalpy increase amount ΔHs in the single-stage hot gas heating mode is because in the multi-stage hot gas heating mode, intermediate-pressure refrigerant with low enthalpy is mixed with the refrigerant during the compression process.

[0229] Therefore, in the multistage hot gas heating mode, the compression work amount corresponding to the product of the suction flow rate Ginj of the intermediate-pressure refrigerant and the increase in enthalpy ΔHm of the intermediate-pressure refrigerant is greater than that in the single-stage hot gas heating mode. As a result, in the multistage hot gas heating mode, the heating capacity of the heating section can be improved more than in the single-stage hot gas heating mode.

[0230] Furthermore, in the vehicle air conditioner 1 of this embodiment, when the single-stage hot gas heating mode is being executed and the blown air temperature TAV is lower than the target blown air temperature TAO, the intermediate-pressure side on-off valve 22c is opened. That is, when the blown air temperature TAV is lower than the target blown air temperature TAO, the mode is switched from the single-stage hot gas heating mode to the multi-stage hot gas heating mode. Therefore, it is possible to prevent a shortage of heating capacity for the blown air.

[0231] Furthermore, in the vehicle air conditioner 1 of this embodiment, when the multistage hot gas heating mode is being executed and the blown air temperature TAV is lower than the target blown air temperature TAO, the throttle opening of the high-stage expansion valve 14c is increased. This increases the pressure of the intermediate-pressure refrigerant and increases the intake flow rate Ginj. This prevents the heating capacity of the blown air from becoming insufficient.

[0232] The heat pump cycle 10 of this embodiment also includes an exterior heat exchanger 16, an air-conditioning expansion valve 14d, and an interior evaporator 18. Therefore, in the vehicle air conditioner 1 of this embodiment, the refrigerant circuit switching unit switches the refrigerant circuit of the heat pump cycle 10, thereby enabling the air-conditioning mode to be performed, in which the blown air, which is the object to be cooled, is cooled.

[0233] The heat pump cycle 10 of this embodiment also includes an outdoor heat exchanger 16, a cooling expansion valve 14e, and a chiller 20. Therefore, in the vehicle air conditioner 1 of this embodiment, the refrigerant circuit switching unit switches the refrigerant circuit of the heat pump cycle 10, thereby enabling a cooling / air-conditioning mode to cool the battery 70, which is an object to be cooled.

[0234] (Second embodiment) In the vehicle air conditioner 1 of this embodiment, as shown in the overall configuration diagram of FIG. 8, an example will be described in which the configuration of the heat pump cycle 10 is simplified compared to the first embodiment.

[0235] Specifically, in the heat pump cycle 10 of the present embodiment, the heating gas-liquid separator 15a, the outdoor unit low-stage expansion valve 14b, the heating intermediate pressure passage 21b, the heating on-off valve 22b, the third three-way joint 12c, the hot gas intermediate pressure passage 21e, and the second check valve 17b are eliminated from the first embodiment. Therefore, the intermediate pressure passage 21c of the present embodiment connects the gas-phase refrigerant outlet of the hot gas gas-liquid separator 15b to the intermediate pressure suction port 11b. The rest of the configuration of the vehicle air conditioner 1 is the same as that of the first embodiment.

[0236] Here, in an embodiment in which the outdoor unit low-stage side expansion valve 14b is eliminated, as in the present embodiment, for clarity of explanation, the outdoor unit high-stage side expansion valve 14a described in the first embodiment will be referred to as the outdoor unit side expansion valve 14a. The outdoor unit side expansion valve 14a is an outdoor unit side pressure reducing section.

[0237] Next, the operation of the vehicle air conditioner 1 of this embodiment configured as described above will be described. As with the first embodiment, the control program of this embodiment repeats control routines at predetermined control cycles, such as reading detection signals and operation signals, determining a target blow-out temperature TAO, selecting an operation mode, and controlling the operation of various control target devices according to the selected operation mode. Each operation mode will be described below.

[0238] (a) Cooling mode In the cooling mode of this embodiment, similarly to the first embodiment, it is possible to switch between the single cooling mode and the cooled cooling mode.

[0239] (a-1) Single cooling mode In the heat pump cycle 10 in the cooling-only mode, the control device 60 sets the outdoor unit side expansion valve 14a to a fully open state, the high-stage side expansion valve 14c to a throttled state, the cooling expansion valve 14d to a throttled state, the cooling expansion valve 14e to a fully closed state, and the bypass side flow control valve 14f to a fully closed state.

[0240] In addition, the control device 60 closes the high-pressure side on-off valve 22a, opens the intermediate-pressure side on-off valve 22c, and closes the low-pressure side on-off valve 22d. Therefore, in the heat pump cycle 10 in the single cooling mode, the refrigerant flows in the same order as in the first embodiment.

[0241] Other operations are the same as those in the first embodiment. Therefore, in the single cooling mode, cooling of the passenger compartment is achieved in the same way as in the first embodiment.

[0242] (a-2) Cooling mode In the heat pump cycle 10 in the cooling / cooling mode, the control device 60 throttles the cooling expansion valve 14e in comparison with the single cooling mode. Therefore, in the heat pump cycle 10 in the cooling / cooling mode, the refrigerant circuit is switched to one in which the refrigerant flows in the same order as in the first embodiment.

[0243] Other operations are the same as those in the first embodiment. Therefore, in the cooling mode, the cooling of the vehicle interior and the cooling of the battery 70 are achieved in the same way as in the first embodiment.

[0244] (b) Heating mode In the cooling mode of this embodiment, it is possible to switch between a single-stage outdoor air heat absorption heating mode, a single-stage hot gas heating mode, and a multi-stage hot gas heating mode.

[0245] (b-4) Single-stage outdoor air heat absorption heating mode The single-stage outdoor air heat absorption heating mode is an operation mode corresponding to the outdoor air heat absorption heating mode described in the first embodiment. The single-stage outdoor air heat absorption heating mode is selected when heat absorbed from the outdoor air can be used as a heat source for heating.

[0246] In the heat pump cycle 10 in the single-stage outdoor air heat absorption heating mode, the control device 60 places the outdoor unit side expansion valve 14a in a throttled state, the high stage side expansion valve 14c in a fully closed state, the air conditioning expansion valve 14d in a fully closed state, the cooling expansion valve 14e in a fully closed state, and the bypass side flow control valve 14f in a fully closed state.

[0247] Furthermore, the control device 60 closes the high-pressure side on-off valve 22a, closes the intermediate-pressure side on-off valve 22c, and opens the low-pressure side on-off valve 22d.

[0248] Therefore, in the heat pump cycle 10 in the single-stage outdoor air heat absorption heating mode, the refrigerant discharged from the discharge port 11c of the compressor 11 is switched to a refrigerant circuit in which it circulates in the order of the water-refrigerant heat exchanger 13, the outdoor unit-side expansion valve 14a, the outdoor heat exchanger 16, the low-pressure side passage 21d, the accumulator 23, and the low-pressure suction port 11a of the compressor 11. Furthermore, the control device 60 controls the operation of the other components, as in the first embodiment.

[0249] Therefore, in the heat pump cycle 10 in the single-stage outdoor air heat absorption heating mode, a single-stage vapor compression refrigeration cycle is configured in which the water-refrigerant heat exchanger 13 functions as a condenser and the outdoor heat exchanger 16 functions as an evaporator.

[0250] In the water-refrigerant heat exchanger 13, the refrigerant dissipates heat to the high-temperature side heat medium, and the high-temperature side heat medium is heated. In the outdoor heat exchanger 16, the refrigerant absorbs heat from the outside air.

[0251] In the high temperature side heat medium circuit 30 in the outside air heat absorption heating mode, the high temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32, similar to the first embodiment.

[0252] Furthermore, in the interior air conditioning unit 50 in the outside air heat absorption heating mode, the temperature-adjusted blown air is blown into the vehicle compartment, thereby heating the vehicle compartment, as in the first embodiment.

[0253] (b-2) Single-stage hot gas heating mode As in the first embodiment, the single-stage hot gas heating mode is selected when the heat absorbed from the outside air cannot be used as a heat source for heating, or when it is determined that the heating capacity of the blown air in the heater core 32 is insufficient compared to the target heating capacity while the single-stage outside air heat absorption heating mode is being executed.

[0254] In the heat pump cycle 10 in the single-stage hot gas heating mode, the control device 60 sets the outdoor unit side expansion valve 14a to a fully closed state, the high stage side expansion valve 14c to a throttled state, the air conditioning expansion valve 14d to a fully closed state, the cooling expansion valve 14e to a throttled state, and the bypass side flow control valve 14f to a throttled state.

[0255] Furthermore, the control device 60 opens the high-pressure side on-off valve 22a, closes the intermediate-pressure side on-off valve 22c, and closes the low-pressure side on-off valve 22d.

[0256] Therefore, in the heat pump cycle 10 in the single-stage hot gas heating mode, the refrigerant flows in the same order as in the first embodiment.

[0257] Other operations are the same as those in the first embodiment. Therefore, in the single-stage hot gas heating mode, heating of the vehicle interior is achieved in the same way as in the first embodiment.

[0258] (b-3) Multi-stage hot gas heating mode As in the first embodiment, the multi-stage hot gas heating mode is selected when the heat absorbed from the outside air cannot be used as a heat source for heating, or when it is determined that the heating capacity of the blown air in the heater core 32 is insufficient compared to the target heating capacity while the single-stage hot gas heating mode is being executed.

[0259] In the heat pump cycle 10 in the multistage hot gas heating mode, the control device 60 sets the outdoor unit side expansion valve 14a to a fully closed state, the high stage side expansion valve 14c to a throttled state, the air conditioning expansion valve 14d to a fully closed state, the cooling expansion valve 14e to a throttled state, and the bypass side flow control valve 14f to a throttled state.

[0260] Furthermore, the control device 60 opens the high-pressure side on-off valve 22a, opens the intermediate-pressure side on-off valve 22c, and closes the low-pressure side on-off valve 22d.

[0261] Therefore, in the heat pump cycle 10 in the multistage hot gas heating mode, the refrigerant flows in the same order as in the first embodiment.

[0262] Other operations are the same as those in the first embodiment. Therefore, in the multistage hot gas heating mode, heating of the vehicle interior is achieved in the same way as in the first embodiment.

[0263] As described above, the vehicle air conditioner 1 of this embodiment can switch between operating modes to provide comfortable air conditioning for the vehicle interior and to appropriately adjust the temperature of the battery 70, which is an on-board device. Furthermore, the same effects as those of the vehicle air conditioner 1 of the first embodiment can be obtained. Therefore, in the multistage hot gas heating mode, the heating section can exhibit a sufficiently high heating capacity without increasing the pressure of the low-pressure refrigerant.

[0264] (Third embodiment) In the vehicle air conditioner 1 of this embodiment, as shown in the overall configuration diagram of FIG. 9, an example will be described in which the configuration of the heat pump cycle 10 is changed from that of the second embodiment.

[0265] Specifically, in the heat pump cycle 10 of the present embodiment, a tenth three-way joint 12j, an eleventh three-way joint 12k, an outdoor unit passage 21g, an outdoor unit on-off valve 22g, and a second high-pressure side on-off valve 22e are added to the second embodiment. Here, in an embodiment in which the second high-pressure side on-off valve 22e is added, as in the present embodiment, for clarity of explanation, the high-pressure side on-off valve 22a described in the first embodiment will be referred to as the first high-pressure side on-off valve 22a.

[0266] The tenth three-way joint 12j is disposed in a refrigerant passage extending from the liquid refrigerant outlet of the hot gas gas-liquid separator 15b to the inlet of the sixth three-way joint 12f. The liquid refrigerant outlet of the hot gas gas-liquid separator 15b is connected to the inlet of the tenth three-way joint 12j. One outlet of the tenth three-way joint 12j is connected to the inlet of the sixth three-way joint 12f.

[0267] The eleventh three-way joint 12k is disposed in a refrigerant passage extending from one outlet of the second three-way joint 12b to the inlet of the outdoor unit expansion valve 14a. One inlet of the eleventh three-way joint 12k is connected to one outlet of the second three-way joint 12b. The outlet of the eleventh three-way joint 12k is connected to the inlet of the outdoor unit expansion valve 14a.

[0268] A second high-pressure side on-off valve 22e is disposed in the refrigerant passage extending from one outlet of the second three-way joint 12b to one inlet of the eleventh three-way joint 12k. The second high-pressure side on-off valve 22e is a refrigerant circuit switching unit that opens and closes the refrigerant passage extending from one outlet of the second three-way joint 12b to one inlet of the eleventh three-way joint 12k.

[0269] The other outlet of the tenth three-way joint 12j is connected to the other inlet of the eleventh three-way joint 12k. The refrigerant passage from the other outlet of the tenth three-way joint 12j to the other inlet of the eleventh three-way joint 12k is an outdoor unit passage 21g that guides the liquid-phase refrigerant separated in the hot gas gas-liquid separator 15b to the inlet of the outdoor unit-side expansion valve 14a.

[0270] An outdoor unit on-off valve 22g is arranged in the outdoor unit passage 21g. The outdoor unit on-off valve 22g is a refrigerant circuit switching unit that opens and closes the outdoor unit passage 21g. Other configurations of the vehicle air conditioner 1 are the same as those in the second embodiment.

[0271] Next, the operation of the vehicle air conditioner 1 of this embodiment configured as described above will be described. As with the first embodiment, the control program of this embodiment repeats control routines at predetermined control cycles, such as reading detection signals and operation signals, determining a target blow-out temperature TAO, selecting an operation mode, and controlling the operation of various control target devices according to the selected operation mode. Each operation mode will be described below.

[0272] (a) Cooling mode In the cooling mode of this embodiment, similarly to the first embodiment, it is possible to switch between the single cooling mode and the cooled cooling mode.

[0273] (a-1) Single cooling mode In the heat pump cycle 10 in the cooling-only mode, the control device 60 sets the outdoor unit side expansion valve 14a to a fully open state, the high-stage side expansion valve 14c to a throttled state, the cooling expansion valve 14d to a throttled state, the cooling expansion valve 14e to a fully closed state, and the bypass side flow control valve 14f to a fully closed state.

[0274] The control device 60 also closes the first high-pressure side on-off valve 22a, opens the intermediate-pressure side on-off valve 22c, closes the low-pressure side on-off valve 22d, opens the second high-pressure side on-off valve 22e, and closes the outdoor unit on-off valve 22g. Therefore, in the heat pump cycle 10 in the single cooling mode, the refrigerant flows in the same order as in the first embodiment.

[0275] Other operations are the same as those in the first embodiment. Therefore, in the single cooling mode, cooling of the passenger compartment is achieved in the same way as in the first embodiment.

[0276] (a-2) Cooling mode In the heat pump cycle 10 in the cooling / cooling mode, the control device 60 throttles the cooling expansion valve 14e in comparison with the single cooling mode. Therefore, in the heat pump cycle 10 in the cooling / cooling mode, the refrigerant circuit is switched to one in which the refrigerant flows in the same order as in the first embodiment.

[0277] Other operations are the same as those in the first embodiment. Therefore, in the cooling mode, the cooling of the vehicle interior and the cooling of the battery 70 are achieved in the same way as in the first embodiment.

[0278] (b) Heating mode In the heating mode of this embodiment, similarly to the first embodiment, it is possible to switch between an outdoor air heat absorption heating mode, a single-stage hot gas heating mode, and a multi-stage hot gas heating mode.

[0279] (b-1) Outdoor air heat absorption heating mode In the heat pump cycle 10 in the outdoor air heat absorption heating mode, the control device 60 places the outdoor unit side expansion valve 14a in a throttled state, the high stage side expansion valve 14c in a throttled state, the air conditioning expansion valve 14d in a fully closed state, the cooling expansion valve 14e in a fully closed state, and the bypass side flow control valve 14f in a fully closed state.

[0280] In addition, the control device 60 opens the first high-pressure side on-off valve 22a, opens the intermediate-pressure side on-off valve 22c, opens the low-pressure side on-off valve 22d, closes the second high-pressure side on-off valve 22e, and opens the outdoor unit on-off valve 22g.

[0281] Therefore, in the heat pump cycle 10 in the outdoor air heat absorption heating mode, the refrigerant discharged from the discharge port 11c of the compressor 11 flows sequentially through the water-refrigerant heat exchanger 13, the high-pressure passage 21a, the high-stage expansion valve 14c, and the hot gas gas-liquid separator 15b. The gas-phase refrigerant separated in the hot gas gas-liquid separator 15b flows sequentially through the intermediate-pressure passage 21c and the intermediate-pressure suction port 11b of the compressor 11. At the same time, the refrigerant circuit is switched to one in which the liquid-phase refrigerant separated in the heating gas-liquid separator 15a flows sequentially through the outdoor unit passage 21g, the outdoor unit expansion valve 14a, the outdoor heat exchanger 16, the low-pressure passage 21d, the accumulator 23, and the low-pressure suction port 11a of the compressor 11.

[0282] Furthermore, the control device 60 controls the throttle opening of the high-stage side expansion valve 14c so that the degree of subcooling SC1 of the refrigerant flowing out from the water-refrigerant heat exchanger 13 approaches the reference degree of subcooling KSC1.

[0283] The control device 60 also controls the throttle opening of the outdoor unit expansion valve 14a so that the opening becomes a predetermined reference opening for the outdoor air heat absorption heating mode. The control device 60 also controls the operation of the other components in the same way as in the outdoor air heat absorption heating mode of the first embodiment.

[0284] Therefore, in the heat pump cycle 10 in the outdoor air heat absorption heating mode, as in the first embodiment, a gas-liquid separation type gas injection cycle is configured in which the water-refrigerant heat exchanger 13 functions as a condenser and the outdoor heat exchanger 16 functions as an evaporator.

[0285] In the high temperature side heat medium circuit 30 in the outside air heat absorption heating mode, the high temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32, similar to the first embodiment.

[0286] Furthermore, in the interior air conditioning unit 50 in the outside air heat absorption heating mode, the temperature-adjusted blown air is blown into the vehicle compartment, thereby heating the vehicle compartment, as in the first embodiment.

[0287] (b-2) Single-stage hot gas heating mode In the heat pump cycle 10 in the single-stage hot gas heating mode, the control device 60 sets the outdoor unit side expansion valve 14a to a fully closed state, the high stage side expansion valve 14c to a fully open state, the air conditioning expansion valve 14d to a fully closed state, the cooling expansion valve 14e to a throttled state, and the bypass side flow control valve 14f to a throttled state.

[0288] The control device 60 also opens the first high-pressure side on-off valve 22a, closes the intermediate-pressure side on-off valve 22c, closes the low-pressure side on-off valve 22d, closes the second high-pressure side on-off valve 22e, and closes the outdoor unit on-off valve 22g.

[0289] Therefore, in the heat pump cycle 10 in the single-stage hot gas heating mode, the refrigerant flows in the same order as in the first embodiment.

[0290] Other operations are the same as those in the first embodiment. Therefore, in the single-stage hot gas heating mode, heating of the vehicle interior is achieved in the same way as in the first embodiment.

[0291] (b-3) Multi-stage hot gas heating mode In the heat pump cycle 10 in the multistage hot gas heating mode, the control device 60 sets the outdoor unit side expansion valve 14a to a fully closed state, the high stage side expansion valve 14c to a throttled state, the air conditioning expansion valve 14d to a fully closed state, the cooling expansion valve 14e to a throttled state, and the bypass side flow control valve 14f to a throttled state.

[0292] The control device 60 also opens the first high-pressure side on-off valve 22a, opens the intermediate-pressure side on-off valve 22c, closes the low-pressure side on-off valve 22d, closes the second high-pressure side on-off valve 22e, and closes the outdoor unit on-off valve 22g.

[0293] Therefore, in the heat pump cycle 10 in the multistage hot gas heating mode, the refrigerant flows in the same order as in the first embodiment.

[0294] Other operations are the same as those in the first embodiment. Therefore, in the multistage hot gas heating mode, heating of the vehicle interior is achieved in the same way as in the first embodiment.

[0295] As described above, the vehicle air conditioner 1 of this embodiment can switch between operating modes to provide comfortable air conditioning for the vehicle interior and to appropriately adjust the temperature of the battery 70, which is an on-board device. Furthermore, the same effects as those of the vehicle air conditioner 1 of the first embodiment can be obtained. Therefore, in the multistage hot gas heating mode, the heating section can exhibit a sufficiently high heating capacity without increasing the pressure of the low-pressure refrigerant.

[0296] Furthermore, the heat pump cycle 10 of this embodiment includes an outdoor unit-side expansion valve 14a, an outdoor heat exchanger 16, and an outdoor unit passage 21g. Therefore, in the vehicle air conditioner 1 of this embodiment, the refrigerant circuit switching unit switches the refrigerant circuit of the heat pump cycle 10, thereby enabling an outdoor air heat absorption heating mode. In the outdoor air heat absorption heating mode, as in the first embodiment, the COP can be improved and efficient heating can be achieved.

[0297] (Fourth embodiment) The vehicle air conditioner 1a of this embodiment includes a heat pump cycle 10a shown in the overall configuration diagram of FIG.

[0298] Specifically, the heat pump cycle 10a of this embodiment does not include the hot gas gas-liquid separator 15b as compared to the third embodiment. Also, the heat pump cycle 10a of this embodiment has a thirteenth three-way joint 12m and an internal heat exchanger 24 added to the third embodiment.

[0299] The thirteenth three-way joint 12m branches the refrigerant flowing out from the fifth three-way joint 12e. Therefore, the thirteenth three-way joint 12m serves as a downstream branching section that branches the refrigerant flowing out from the water-refrigerant heat exchanger 13 in the multistage hot gas heating mode. One outlet of the thirteenth three-way joint 12m is connected to the inlet side of the low-temperature side passage of the internal heat exchanger 24. The other outlet of the thirteenth three-way joint 12m is connected to the inlet side of the high-temperature side passage of the internal heat exchanger 24.

[0300] A high-stage expansion valve 14c is disposed in a refrigerant passage connecting one outlet of the thirteenth three-way joint 12m and the inlet of the low-temperature side passage of the internal heat exchanger 24. Therefore, the high-stage expansion valve 14c of this embodiment serves as a high-stage pressure reduction section that reduces the pressure of one of the refrigerants branched at the thirteenth three-way joint 12m.

[0301] The internal heat exchanger 24 has a low-temperature side passage and a high-temperature side passage. The low-temperature side passage is a refrigerant passage through which the refrigerant decompressed by the high-stage side expansion valve 14c flows. The high-temperature side passage is a refrigerant passage through which the other refrigerant branched at the thirteenth three-way joint 12m flows. Therefore, the internal heat exchanger 24 is an internal heat exchange unit that exchanges heat between the refrigerant decompressed by the high-stage side expansion valve 14c and the other refrigerant branched at the thirteenth three-way joint 12m.

[0302] The intermediate pressure passage 21c of this embodiment connects the outlet of the low-temperature side passage of the internal heat exchanger 24 to the intermediate-pressure suction port 11b. The outlet of the high-temperature side passage of the internal heat exchanger 24 is connected to the inlet side of the tenth three-way joint 12j. Therefore, the cooling expansion valve 14d and the cooling expansion valve 14e of this embodiment serve as a low-stage side decompression section that decompresses the other refrigerant branched at the thirteenth three-way joint 12m, that is, the refrigerant that flows out of the internal heat exchanger 24. The rest of the configuration of the vehicle air conditioner 1a is the same as that of the vehicle air conditioner 1 described in the first embodiment.

[0303] Next, the operation of the vehicle air conditioner 1a of this embodiment configured as described above will be described. In the control program of this embodiment, similar to the first embodiment, a control routine is repeated at each predetermined control cycle, including reading of detection signals and operation signals, determination of a target blow-out temperature TAO, selection of an operation mode, and control of various controlled devices. Each operation mode will be described below.

[0304] (a) Cooling mode In the cooling mode of this embodiment, similarly to the first embodiment, it is possible to switch between the single cooling mode and the cooled cooling mode.

[0305] (a-1) Single cooling mode In the heat pump cycle 10a in the cooling-only mode, the control device 60 sets the outdoor unit side expansion valve 14a to a fully open state, the high-stage side expansion valve 14c to a throttled state, the cooling expansion valve 14d to a throttled state, the cooling expansion valve 14e to a fully closed state, and the bypass side flow control valve 14f to a fully closed state.

[0306] The control device 60 also closes the first high-pressure side on-off valve 22a, opens the intermediate-pressure side on-off valve 22c, closes the low-pressure side on-off valve 22d, opens the second high-pressure side on-off valve 22e, and closes the outdoor unit on-off valve 22g.

[0307] Therefore, in the heat pump cycle 10a in the cooling-only mode, the refrigerant discharged from the discharge port 11c of the compressor 11 flows, in this order, through the water-refrigerant heat exchanger 13, the fully open outdoor unit-side expansion valve 14a, the outdoor heat exchanger 16, and the thirteenth three-way joint 12m. One branch of the refrigerant at the thirteenth three-way joint 12m flows, in this order, through the high-pressure expansion valve 14c, the low-temperature side passage of the internal heat exchanger 24, the intermediate-pressure passage 21c, and the intermediate-pressure suction port 11b of the compressor 11. At the same time, the other branch of the refrigerant at the thirteenth three-way joint 12m is switched to a refrigerant circuit that flows, in this order, through the high-temperature side passage of the internal heat exchanger 24, the cooling expansion valve 14d, the indoor evaporator 18, the evaporation pressure control valve 19, the accumulator 23, and the low-pressure suction port 11a of the compressor 11.

[0308] Furthermore, the control device 60 controls the throttle opening of the cooling expansion valve 14d so that the degree of subcooling SC2 of the refrigerant flowing out from the outdoor heat exchanger 16 approaches a predetermined reference degree of subcooling KSC2. The control device 60 also controls the throttle opening of the high-stage expansion valve 14c so that the degree of subcooling becomes a predetermined reference degree of opening for the cooling mode. The reference degree of opening for the cooling mode is determined so that the refrigerant flowing into the intermediate-pressure suction port 11b becomes a gas-phase refrigerant. The control device 60 also controls the operation of the other components in the same manner as in the single cooling mode of the first embodiment.

[0309] Therefore, the heat pump cycle 10a in the cooling-only mode is configured as a two-stage pressure-boosting vapor compression refrigeration cycle in which the water-refrigerant heat exchanger 13 and the outdoor heat exchanger 16 function as condensers and the indoor evaporator 18 functions as an evaporator. More specifically, the heat pump cycle 10a in the cooling-only mode of this embodiment is configured as a so-called internal heat exchange gas injection cycle.

[0310] As in the first embodiment, the high-temperature side heat medium is heated in the water-refrigerant heat exchanger 13. In the outdoor heat exchanger 16, the refrigerant dissipates heat to the outdoor air. In the indoor evaporator 18, the blown air is cooled.

[0311] In the high-temperature side heat medium circuit 30 in the single cooling mode, the high-temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32, similar to the first embodiment.

[0312] Furthermore, in the interior air conditioning unit 50 in the single cooling mode, the temperature-adjusted blown air is blown into the vehicle compartment, thereby cooling the vehicle compartment, as in the first embodiment.

[0313] (a-2) Cooling mode In the heat pump cycle 10a in the cooling / air-cooling mode, the control device 60 throttles the cooling expansion valve 14e in comparison with the single cooling mode.

[0314] Therefore, in the heat pump cycle 10a in the cooling / air-conditioning mode, the refrigerant discharged from the discharge port 11c of the compressor 11 flows in the same manner as in the single cooling mode. At the same time, the other refrigerant branched at the thirteenth three-way joint 12m is switched to a refrigerant circuit that flows in the high-temperature side passage of the internal heat exchanger 24, the cooling expansion valve 14e, the chiller 20, the accumulator 23, and the low-pressure suction port 11a of the compressor 11 in this order.

[0315] That is, in the heat pump cycle 10a in the cooling / air-cooling mode, the refrigerant circuit is switched to one in which the indoor evaporator 18 and the chiller 20 are connected in parallel with respect to the flow of the refrigerant.

[0316] Furthermore, the control device 60 controls the throttle opening of the cooling expansion valve 14e to a predetermined throttle opening for the cooling / air-cooling mode. The control device 60 also controls the operation of the other components in the same manner as in the cooling / air-cooling mode of the first embodiment.

[0317] Therefore, in the heat pump cycle 10a in the cooling / air-conditioning mode, an internal heat exchange type gas injection cycle is configured in which the water-refrigerant heat exchanger 13 and the outdoor heat exchanger 16 function as condensers, and the indoor evaporator 18 and the chiller 20 function as evaporators.

[0318] As in the first embodiment, the high-temperature side heat medium is heated in the water-refrigerant heat exchanger 13. In the outdoor heat exchanger 16, the refrigerant dissipates heat to the outdoor air. In the indoor evaporator 18, the blown air is cooled. In the chiller 20, the low-temperature side heat medium is cooled.

[0319] In the high-temperature side heat medium circuit 30 in the single cooling mode, the high-temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32, similar to the first embodiment.

[0320] In the low-temperature side heat medium circuit 40 in the cooling / air-cooling mode, similarly to the first embodiment, the low-temperature side heat medium cooled by the chiller 20 flows through the coolant passage 70a of the battery 70. This cools the battery 70.

[0321] Furthermore, in the interior air conditioning unit 50 in the single cooling mode, the temperature-adjusted blown air is blown into the vehicle compartment, thereby cooling the vehicle compartment, as in the first embodiment.

[0322] (b) Heating mode In the heating mode of this embodiment, similarly to the first embodiment, it is possible to switch between an outdoor air heat absorption heating mode, a single-stage hot gas heating mode, and a multi-stage hot gas heating mode.

[0323] (b-1) Outdoor air heat absorption heating mode In the heat pump cycle 10a in the cooling-only mode, the control device 60 places the outdoor unit side expansion valve 14a in a throttled state, the high-stage side expansion valve 14c in a throttled state, the cooling expansion valve 14d in a fully closed state, the cooling expansion valve 14e in a fully closed state, and the bypass side flow control valve 14f in a fully closed state.

[0324] In addition, the control device 60 opens the first high-pressure side on-off valve 22a, opens the intermediate-pressure side on-off valve 22c, opens the low-pressure side on-off valve 22d, closes the second high-pressure side on-off valve 22e, and opens the outdoor unit on-off valve 22g.

[0325] Therefore, in the heat pump cycle 10a in the outdoor air heat absorption heating mode, the refrigerant discharged from the discharge port 11c of the compressor 11 flows through the water-refrigerant heat exchanger 13, the high-pressure side passage 21a, and the thirteenth three-way joint 12m, in that order. One branch of the refrigerant at the thirteenth three-way joint 12m flows through the high-pressure side expansion valve 14c, the low-temperature side passage of the internal heat exchanger 24, the intermediate-pressure passage 21c, and the intermediate-pressure suction port 11b of the compressor 11, in that order. At the same time, the other branch of the refrigerant at the thirteenth three-way joint 12m is switched to a refrigerant circuit that flows through the high-temperature side passage of the internal heat exchanger 24, the outdoor unit passage 21g, the outdoor unit expansion valve 14a, the outdoor heat exchanger 16, the low-pressure side passage 21d, the accumulator 23, and the low-pressure suction port 11a of the compressor 11, in that order.

[0326] Furthermore, the control device 60 controls the throttle opening of the outdoor unit-side expansion valve 14a so that the degree of subcooling SC1 of the refrigerant flowing out of the water-refrigerant heat exchanger 13 approaches the reference degree of subcooling KSC1. The control device 60 also controls the throttle opening of the high-stage expansion valve 14c so that the degree of subcooling is equal to a predetermined reference degree of opening for the heating mode. The reference degree of opening for the heating mode is determined so that the refrigerant flowing into the intermediate-pressure suction port 11b becomes gas-phase refrigerant. The control device 60 also controls the operation of the other components in the same way as in the outdoor air heat absorption heating mode of the first embodiment.

[0327] Therefore, the heat pump cycle 10a in the outdoor air heat absorption heating mode is configured as an internal heat exchange type gas injection cycle in which the water-refrigerant heat exchanger 13 functions as a condenser and the outdoor heat exchanger 16 functions as an evaporator.

[0328] Then, similarly to the first embodiment, the high-temperature side heat medium is heated in the water-refrigerant heat exchanger 13. In the outdoor heat exchanger 16, the refrigerant absorbs heat from the outside air.

[0329] In the high temperature side heat medium circuit 30 in the outside air heat absorption heating mode, the high temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32, similar to the first embodiment.

[0330] Furthermore, in the interior air conditioning unit 50 in the outside air heat absorption heating mode, the temperature-adjusted blown air is blown into the vehicle compartment, thereby heating the vehicle compartment, as in the first embodiment.

[0331] (b-2) Single-stage hot gas heating mode In the heat pump cycle 10a in the single-stage hot gas heating mode, the control device 60 sets the outdoor unit side expansion valve 14a to a fully closed state, the high stage side expansion valve 14c to a fully closed state, the air conditioning expansion valve 14d to a fully closed state, the cooling expansion valve 14e to a throttled state, and the bypass side flow control valve 14f to a throttled state.

[0332] The control device 60 also opens the first high-pressure side on-off valve 22a, closes the intermediate-pressure side on-off valve 22c, closes the low-pressure side on-off valve 22d, closes the second high-pressure side on-off valve 22e, and closes the outdoor unit on-off valve 22g.

[0333] 11, the refrigerant discharged from the discharge port 11c of the compressor 11 circulates in this order through the water-refrigerant heat exchanger 13, the high-pressure side passage 21a, the high-temperature side passage of the internal heat exchanger 24, the cooling expansion valve 14e, the chiller 20, the seventh three-way joint 12g, the accumulator 23, and the low-pressure suction port 11a of the compressor 11. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates in this order through the bypass-side flow control valve 14f disposed in the bypass passage 21f, the seventh three-way joint 12g, and the low-pressure suction port 11a of the compressor 11.

[0334] Here, in the single-stage hot gas heating mode, the high-stage expansion valve 14c is fully closed and the outdoor unit on-off valve 22g is closed, so that no refrigerant flows through the low-temperature side passage of the internal heat exchanger 24. For this reason, in the single-stage hot gas heating mode, the refrigerant does not exchange heat with the refrigerant flowing through the low-temperature side passage in the high-temperature side passage of the internal heat exchanger 24, and the high-temperature side passage of the internal heat exchanger 24 simply serves as a refrigerant passage.

[0335] Therefore, in the heat pump cycle 10a in the single-stage hot gas heating mode, the refrigerant flows in the same order as in the first embodiment.

[0336] Other operations are the same as those in the first embodiment. Therefore, in the single-stage hot gas heating mode, heating of the vehicle interior is achieved in the same way as in the first embodiment.

[0337] (b-3) Multi-stage hot gas heating mode In the heat pump cycle 10a in the multistage hot gas heating mode, the control device 60 sets the outdoor unit side expansion valve 14a in a fully closed state, the high stage side expansion valve 14c in a throttled state, the air conditioning expansion valve 14d in a fully closed state, the cooling expansion valve 14e in a throttled state, and the bypass side flow control valve 14f in a throttled state.

[0338] The control device 60 also opens the first high-pressure side on-off valve 22a, opens the intermediate-pressure side on-off valve 22c, closes the low-pressure side on-off valve 22d, closes the second high-pressure side on-off valve 22e, and closes the outdoor unit on-off valve 22g.

[0339] 12, in the heat pump cycle 10a in the single-stage hot gas heating mode, the refrigerant discharged from the discharge port 11c of the compressor 11 flows through the water-refrigerant heat exchanger 13, the high-pressure side passage 21a, and the thirteenth three-way joint 12m, in that order. One of the refrigerants branched at the thirteenth three-way joint 12m flows through the high-pressure expansion valve 14c, the low-temperature side passage of the internal heat exchanger 24, the intermediate-pressure passage 21c, and the intermediate-pressure suction port 11b of the compressor 11, in that order. The other refrigerant branched at the thirteenth three-way joint 12m flows through the high-temperature side passage of the internal heat exchanger 24, the cooling expansion valve 14e, the chiller 20, the seventh three-way joint 12g, the accumulator 23, and the low-pressure suction port 11a of the compressor 11, in that order. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates through the bypass-side flow control valve 14f arranged in the bypass passage 21f, the seventh three-way joint 12g, and the low-pressure intake port 11a of the compressor 11 in that order.

[0340] Furthermore, when the opening of the air mix door 54 can be adjusted to make the blown air temperature TAV the target blowing temperature TAO, the control device 60 controls the throttling opening of the high-stage expansion valve 14c so that it becomes the standard opening for the heating mode, as in the outdoor air heat absorption heating mode.

[0341] On the other hand, even if the air mix door 54 is displaced to a position where the ventilation passage on the heater core 32 side is fully open and the cold air bypass passage 55 is fully closed, if the blowing air temperature TAV is lower than the target blowing temperature TAO, the throttle opening of the high-stage expansion valve 14c is increased from its current value to the extent that the refrigerant flowing into the intermediate-pressure suction port 11b becomes gas-phase refrigerant. Also, the control device 60 controls the operation of the other components in the same way as in the multi-stage hot gas heating mode of the first embodiment.

[0342] Therefore, in the heat pump cycle 10 in the multistage hot gas heating mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0343] That is, the flow of high-pressure refrigerant (point a13 in FIG. 13) discharged from the discharge port 11c of the compressor 11 is branched at the first three-way joint 12a. One of the refrigerant branches at the first three-way joint 12a flows into the water-refrigerant heat exchanger 13 and dissipates heat to the high-temperature side heat medium (from point a13 to point b7 in FIG. 13). This heats the high-temperature side heat medium.

[0344] The refrigerant flowing out of the water-refrigerant heat exchanger 13 flows into the high-pressure side passage 21a. The flow of the refrigerant flowing into the high-pressure side passage 21a is branched at the thirteenth three-way joint 12m. One of the refrigerant branches at the thirteenth three-way joint 12m flows into the high-stage expansion valve 14c and is decompressed (from point b13 to point c13 in FIG. 13).

[0345] The refrigerant flowing out of the high-stage expansion valve 14c flows into the low-temperature side passage of the internal heat exchanger 24. When flowing through the low-temperature side passage, the refrigerant that has flowed into the low-temperature side passage is heated by heat exchange with the refrigerant flowing through the high-temperature side passage (from point c13 to point e13 in FIG. 13).

[0346] The refrigerant that has been heated while flowing through the low-temperature side passage of the internal heat exchanger 24 passes through the intermediate-pressure passage 21c and is drawn into the compressor 11 from the intermediate-pressure suction port 11b. The intermediate-pressure refrigerant drawn through the intermediate-pressure suction port 11b joins with the refrigerant that is being compressed from low pressure to high pressure inside the compressor 11 (point i7 in FIG. 7).

[0347] The other refrigerant branched at the thirteenth three-way joint 12m flows into the high-temperature side passage of the internal heat exchanger 24. When the refrigerant that has flowed into the high-temperature side passage flows through the high-temperature side passage, it exchanges heat with the refrigerant flowing through the low-temperature side passage and is cooled (from point b13 to point d13 in FIG. 13).

[0348] The refrigerant that has been cooled while flowing through the high-temperature side passage of the internal heat exchanger 24 flows into the cooling expansion valve 14e and is reduced in pressure (from point d13 to point f13 in FIG. 13). The low-pressure refrigerant with a relatively low enthalpy that has flowed out of the cooling expansion valve 14e flows through the chiller 20 into the other inlet of the seventh three-way joint 12g.

[0349] In the multistage hot gas heating mode, the low-temperature side pump 41 is stopped, so the refrigerant that has flowed into the chiller 20 does not exchange heat with the low-temperature side heat medium.

[0350] The other refrigerant branched at the first three-way joint 12a flows into the bypass passage 21f, and is decompressed by the bypass-side flow control valve 14f through flow rate adjustment (from point a13 to point h13 in FIG. 13), as in the single-stage hot gas heating mode. The low-pressure refrigerant with a relatively high enthalpy decompressed by the bypass-side flow control valve 14f flows into one inlet of the seventh three-way joint 12g.

[0351] The refrigerant that joins at the seventh three-way joint 12g flows into the accumulator 23 and is separated into gas and liquid. The gas-phase refrigerant separated in the accumulator 23 (point g13 in FIG. 13) is drawn into the compressor 11 from the low-pressure suction port 11a and compressed.

[0352] In the high-temperature side heat medium circuit 30 in the multistage hot gas heating mode, the high-temperature side heat medium heated in the water-refrigerant heat exchanger 13 flows into the heater core 32, as in the single cooling mode.

[0353] In addition, in the interior air conditioning unit 50 in the multistage hot gas heating mode, the temperature-adjusted ventilation air is blown into the vehicle compartment, as in the outside air heat absorption heating mode, thereby realizing heating of the vehicle compartment.

[0354] As described above, the vehicle air conditioner 1a of this embodiment can switch between operation modes to provide comfortable air conditioning for the vehicle interior and to appropriately adjust the temperature of the battery 70, which is an on-board device. Furthermore, the same effects as those of the vehicle air conditioner 1 described in the first embodiment can be obtained.

[0355] More specifically, in the multistage hot gas heating mode, the cycle can be operated stably, as in the first embodiment. In the multistage hot gas heating mode, the blown air can be stably heated in the heating section using heat generated by the compression work of the compressor 11, without using heat absorbed from the outside air, as in the single-stage hot gas heating mode.

[0356] Furthermore, in the multi-stage hot gas heating mode, as in the first embodiment, the refrigerant heated in the internal heat exchanger 24 is drawn into the intermediate-pressure suction port 11b, thereby increasing the compression work of the compressor 11 more than in the single-stage hot gas heating mode. Therefore, the heating section can exhibit a sufficiently high heating capacity without increasing the pressure of the low-pressure refrigerant.

[0357] The heat pump cycle 10a of this embodiment also includes an outdoor unit-side expansion valve 14a, an outdoor heat exchanger 16, and an outdoor unit passage 21g. Therefore, in the vehicle air conditioner 1a of this embodiment, the refrigerant circuit switching unit switches the refrigerant circuit of the heat pump cycle 10, thereby enabling an outdoor air heat absorption heating mode. In the outdoor air heat absorption heating mode, as in the first embodiment, the COP can be improved and efficient heating can be achieved.

[0358] The heat pump cycle 10a of this embodiment also includes an exterior heat exchanger 16, an air-conditioning expansion valve 14d, and an interior evaporator 18. Therefore, in the vehicle air conditioner 1a of this embodiment, the refrigerant circuit switching unit switches the refrigerant circuit of the heat pump cycle 10, thereby enabling the air-conditioning mode to be performed to cool the blown air, similar to the first embodiment.

[0359] The heat pump cycle 10a of the present embodiment also includes an exterior heat exchanger 16, a cooling expansion valve 14e, and a chiller 20. Therefore, in the vehicle air conditioner 1a of the present embodiment, the refrigerant circuit switching unit switches the refrigerant circuit of the heat pump cycle 10, thereby enabling the vehicle air conditioner 1a to execute a cooling / air-conditioning mode for cooling the battery 70, similar to the first embodiment.

[0360] (Fifth embodiment) In the vehicle air conditioner 1 of this embodiment, as shown in the overall configuration diagram of FIG. 14, an example will be described in which the configuration of the heat pump cycle 10 is changed from that of the third embodiment.

[0361] Specifically, in the heat pump cycle 10 of the present embodiment, the hot gas gas-liquid separator 15b and the accumulator 23 are eliminated compared to the third embodiment. Also, in the heat pump cycle 10 of the present embodiment, a receiver 25 is added compared to the third embodiment.

[0362] The receiver 25 is a high-pressure side liquid storage section that separates the refrigerant that flows into it into gas and liquid and stores the separated liquid-phase refrigerant as surplus refrigerant for the cycle. The receiver 25 is arranged in the same manner as the hot gas gas-liquid separator 15b.

[0363] Therefore, the outlet side of the high-stage expansion valve 14c is connected to the inlet of the receiver 25. The inlet side of the intermediate pressure passage 21c is connected to the gas phase refrigerant outlet of the receiver 25. Furthermore, the inlet side of the tenth three-way joint 12j is connected to the liquid phase refrigerant outlet of the receiver 25. The rest of the configuration of the vehicle air conditioner 1 is the same as that of the first embodiment.

[0364] Next, the operation of the vehicle air conditioner 1 of this embodiment with the above configuration will be described. The basic operation of the vehicle air conditioner 1 of this embodiment is the same as that of the third embodiment.

[0365] (a-1) Single cooling mode In the single cooling mode, unlike the single cooling mode of the third embodiment, the control device 60 controls the throttle opening of the cooling expansion valve 14d so that the superheat degree SHE of the refrigerant on the outlet side of the indoor evaporator 18 approaches a predetermined reference superheat degree KSHE. The superheat degree SHE can be determined from the evaporator-side refrigerant temperature Te and the evaporator-side refrigerant pressure Pe detected by the evaporator-side refrigerant temperature / pressure sensor 62d.

[0366] Other operations are the same as those in the third embodiment. Therefore, in the single cooling mode, cooling of the passenger compartment is achieved in the same way as in the third embodiment.

[0367] Furthermore, in the single cooling mode of this embodiment, the refrigerant on the outlet side of the indoor evaporator 18 becomes a gas-phase refrigerant having a degree of superheat. This makes it possible to increase the enthalpy difference, obtained by subtracting the enthalpy of the refrigerant on the inlet side from the enthalpy of the refrigerant on the outlet side of the indoor evaporator 18, more than in the third embodiment, thereby improving the cooling capacity of the blown air exerted by the indoor evaporator 18. In addition, liquid compression of the compressor 11 can be suppressed.

[0368] (a-2) Cooling mode In the cooling / cooling mode, in contrast to the cooling / cooling mode of the third embodiment, the control device 60 controls the throttle opening of the cooling expansion valve 14d so that the superheat SHE of the refrigerant on the outlet side of the indoor evaporator 18 approaches the reference superheat KSHE.

[0369] Other operations are the same as those in the third embodiment. Therefore, in the cooling mode, the cooling of the vehicle interior and the cooling of the battery 70 are achieved in the same way as in the third embodiment.

[0370] Furthermore, in the cooling / air-cooling mode of this embodiment, as in the single cooling mode, the cooling capacity of the indoor evaporator 18 for the blown air can be improved more than in the third embodiment. In addition, the liquid compression of the compressor 11 can be suppressed.

[0371] (b-1) Outdoor air heat absorption heating mode In the outdoor air heat absorption heating mode, in contrast to the outdoor air heat absorption heating mode of the third embodiment, the control device 60 controls the throttle opening of the air conditioning expansion valve 14d so that the superheat SH2 of the refrigerant on the outlet side of the outdoor heat exchanger 16 approaches the reference superheat KSH2.

[0372] Other operations are the same as those in the third embodiment. Therefore, in the outside air heat absorption heating mode, heating of the vehicle interior is achieved in the same way as in the third embodiment.

[0373] Furthermore, in the outdoor air heat absorption heating mode of this embodiment, the refrigerant on the outlet side of the outdoor heat exchanger 16 becomes a gas-phase refrigerant with a degree of superheat. This increases the amount of heat absorbed by the refrigerant in the outdoor heat exchanger 16 compared to the first embodiment, thereby improving the heating capacity of the blown air. In addition, liquid compression of the compressor 11 can be suppressed.

[0374] (b-2) Single-stage hot gas heating mode In the single-stage hot gas heating mode, unlike the single-stage hot gas heating mode of the third embodiment, the control device 60 controls the throttle opening of the cooling expansion valve 14e so that the superheat SHC of the refrigerant flowing out of the seventh three-way joint 12g approaches the reference superheat SHC. The superheat SHC can be determined from the chiller-side refrigerant temperature Tc and chiller-side refrigerant pressure Pc detected by the chiller-side refrigerant temperature and pressure sensor 62e.

[0375] Other operations are the same as those in the third embodiment. Therefore, in the single-stage hot gas heating mode, heating of the vehicle interior is achieved in the same way as in the third embodiment.

[0376] Furthermore, in the single-stage hot gas heating mode of this embodiment, the refrigerant flowing out from the seventh three-way joint 12g becomes a gas-phase refrigerant with a degree of superheat, which can suppress liquid compression in the compressor 11 and ensure stable operation of the cycle.

[0377] (b-3) Multi-stage hot gas heating mode In the multistage hot gas heating mode, in contrast to the multistage hot gas heating mode of the third embodiment, the control device 60 controls the throttle opening of the cooling expansion valve 14e so that the superheat SHC of the refrigerant flowing out from the seventh three-way joint 12g approaches the reference superheat KSHC.

[0378] Other operations are the same as those in the third embodiment. Therefore, in the multistage hot gas heating mode, heating of the vehicle interior is achieved in the same way as in the third embodiment.

[0379] Furthermore, in the multistage hot gas heating mode of this embodiment, the refrigerant flowing out of the seventh three-way joint 12g becomes a gas-phase refrigerant with a degree of superheat, which suppresses liquid compression in the compressor 11 and allows the cycle to operate stably.

[0380] As described above, the vehicle air conditioner 1 of this embodiment can switch between operating modes to provide comfortable air conditioning for the vehicle interior and to appropriately adjust the temperature of the battery 70, which is an on-board device. Furthermore, the same effects as those of the vehicle air conditioner 1 of the first embodiment can be obtained. Therefore, in the multistage hot gas heating mode, the heating section can exhibit a sufficiently high heating capacity without increasing the pressure of the low-pressure refrigerant.

[0381] (Other embodiments) The present invention is not limited to the above-described embodiment, and various modifications can be made as follows without departing from the spirit of the present invention.

[0382] (1) In the above embodiment, an example was described in which the heat pump cycle device according to the present invention was applied to a vehicle air conditioner. However, the application of the heat pump cycle device is not limited to vehicle air conditioners. For example, the heat pump cycle device may be applied to an air conditioner that only conditions the air in the space to be air-conditioned, without adjusting the temperature of a heat-generating device. For example, the heat pump cycle device may be applied to a hot water supply system that heats water for domestic use, etc., as the object to be heated.

[0383] In the above embodiment, an example has been described in which the temperature of the battery 70 is adjusted as an in-vehicle device to be temperature-adjusted, but the in-vehicle device is not limited to the battery 70. For example, the temperature of an inverter, a PCU, a transaxle, a control device for ADAS, etc. may be adjusted. Furthermore, the temperature of a plurality of in-vehicle devices may be adjusted.

[0384] The inverter supplies power to the motor generator, etc. The PCU is a power control unit that transforms electricity and distributes power. The transaxle is a power transmission mechanism that integrates the transmission, differential gear, etc. The ADAS control device is a control device for advanced driver assistance systems.

[0385] (2) The configuration of the heat pump cycle device according to the present invention is not limited to the configuration disclosed in the above-described embodiment.

[0386] In the above embodiment, an example has been described in which the heating section is formed by the components of the water-refrigerant heat exchanger 13 and the high-temperature side heat medium circuit 30, but the present invention is not limited to this.

[0387] For example, an indoor condenser may be used as the heating unit. The indoor condenser is a heat exchange unit for heating the blown air by exchanging heat between one of the refrigerant discharged from the first three-way joint 12a and the blown air that has passed through the indoor evaporator 18. The indoor condenser may be disposed in the air passage of the indoor air-conditioning unit 50 in the same manner as the heater core 32.

[0388] Furthermore, in the above embodiment, an example has been described in which the sixth three-way joint 12f, which is the mixing section, is disposed downstream of the chiller 20 in the refrigerant flow direction, but the present invention is not limited to this.

[0389] For example, the seventh three-way joint 12g may be disposed downstream of the cooling expansion valve 14e and upstream of the refrigerant flow of the chiller 20. This allows the refrigerant flowing out of the cooling expansion valve 14e and the refrigerant flowing out of the bypass-side flow adjustment valve 14f to be mixed homogeneously when they flow through the refrigerant passage of the chiller 20. In addition, in the first to fourth embodiments, the seventh three-way joint 12g may be eliminated and the end of the bypass passage 21f may be directly connected to the accumulator 23.

[0390] In the above-described embodiment, the heating gas-liquid separator 15a and the hot gas gas-liquid separator 15b are described as centrifugal separation units, but the present invention is not limited to this. For example, an impingement gas-liquid separator may be used. The impingement gas-liquid separator has a collision part that causes the refrigerant to collide, and separates the high-density liquid refrigerant from the refrigerant whose velocity has decreased upon collision with the collision part by allowing the liquid refrigerant to fall.

[0391] In the above-described embodiment, an example has been described in which a variable throttle mechanism constituted by a mechanical mechanism is employed as the evaporating pressure regulating valve 19, but an electric variable throttle mechanism similar to the bypass side flow rate regulating valve 14f, etc. may also be employed as the evaporating pressure regulating valve 19. Furthermore, if frost does not form on the indoor evaporator 18, the evaporating pressure regulating valve 19 may be eliminated.

[0392] Furthermore, multiple cycle components may be integrated to the extent that the above-described effects can be obtained. For example, a joint portion having a four-way joint structure in which the eighth three-way joint 12h and the ninth three-way joint 12i are integrated may be employed.

[0393] In the fourth embodiment, the intermediate-pressure side opening / closing valve 22c is disposed as the intermediate-pressure side opening / closing unit, but this is not limiting. The intermediate-pressure passage 21c may be closed by the full-closing function of the high-pressure side expansion valve 14c. In other words, the high-pressure side expansion valve 14c may also function as the intermediate-pressure side opening / closing unit.

[0394] In the above-described embodiment, the refrigerant used in the heat pump cycle 10, 10a is R1234yf, but this is not limiting. For example, R134a, R600a, R410A, R404A, R32, R407C, etc. may be used. Alternatively, a mixed refrigerant containing a mixture of two or more of these refrigerants may be used. Furthermore, carbon dioxide may be used as the refrigerant to configure a supercritical refrigeration cycle in which the high-pressure side refrigerant pressure is equal to or higher than the critical pressure of the refrigerant.

[0395] In the above embodiment, the refrigeration oil is PAG oil (i.e., polyalkylene glycol oil), but the present invention is not limited to this. For example, POE (i.e., polyol ester) may be used.

[0396] In the above embodiment, an example was described in which an ethylene glycol aqueous solution was used as the heat medium, low-temperature heat medium, and high-temperature heat medium, but this is not limiting. For example, a solution containing dimethylpolysiloxane or nanofluid, antifreeze, an aqueous liquid refrigerant containing alcohol, or a liquid medium containing oil may also be used.

[0397] Furthermore, the group of control sensors connected to the input side of the control device 60 is not limited to the detection units disclosed in the above-described embodiment. Various detection units may be added as needed.

[0398] (3) The control aspects of the heat pump cycle device according to the present invention are not limited to the control aspects disclosed in the above-described embodiments.

[0399] In the above-described embodiment, the vehicle air conditioners 1, 1a are described as being capable of implementing various operating modes, but the heat pump cycle device according to the present invention does not necessarily have to be capable of implementing all of the operating modes described above. As long as it is capable of implementing at least the multistage hot gas heating mode, the heating section can exhibit a sufficiently high heating capacity without increasing the pressure of the low-pressure refrigerant.

[0400] Furthermore, the vehicle air conditioner 1, 1a may be capable of executing other operation modes.

[0401] For example, a dehumidifying and heating mode may be implemented to dehumidify and heat the vehicle interior. For example, an equipment cooling mode may be implemented to solely cool the battery 70 without air-conditioning the vehicle interior. In the equipment cooling mode, similar to the cooling and cooling mode described above, the refrigerant circuits of the heat pump cycles 10, 10a are switched and the air-conditioning expansion valve 14d is fully closed. Furthermore, the control device 60 may stop the interior blower 52.

[0402] Also, for example, a dehumidifying and heating mode may be implemented in which the blown air cooled and dehumidified by the interior evaporator 18 is reheated by the heater core 32 and blown into the vehicle interior. In the dehumidifying and heating mode, the high-temperature heat medium flowing into the heater core 32 may be heat absorbed by the refrigerant from the outside air in the exterior heat exchanger 16.

[0403] As the dehumidifying heating mode, a series dehumidifying heating mode may be executed in which the refrigerant flow out of the water-refrigerant heat exchanger 13, which is a heating unit, is switched to a refrigerant circuit that connects the outdoor heat exchanger 15 and the indoor evaporator 18 in series. As the dehumidifying heating mode, a parallel dehumidifying heating mode may be executed in which the refrigerant flow out of the water-refrigerant heat exchanger 13, which is a heating unit, is switched to a refrigerant circuit that connects the outdoor heat exchanger 15 and the indoor evaporator 18 in series.

[0404] The heat pump cycle device disclosed in this specification has the following features. (Item 1) a compressor (11) that compresses low-pressure refrigerant drawn through a low-pressure suction port (11a) and discharges the refrigerant through a discharge port (11c), and that draws intermediate-pressure refrigerant drawn through an intermediate-pressure suction port (11b) and causes the low-pressure refrigerant to merge with the refrigerant in the process of being compressed; an upstream branch portion (12a) that branches the flow of high-pressure refrigerant discharged from the discharge port; a heating section (13, 30) that heats an object to be heated using one of the high-pressure refrigerants branched at the upstream branch section as a heat source; a high-stage pressure reducing section (14c) that reduces the pressure of the refrigerant flowing out from the heating section; a hot gas gas-liquid separation section (15b) that separates the refrigerant flowing out from the high-stage side pressure reduction section into gas and liquid; a low-stage side pressure reducing section (14d, 14e) that reduces the pressure of the liquid phase refrigerant separated in the hot gas gas-liquid separation section; a bypass passage (21f) for guiding the other high-pressure refrigerant branched at the upstream branch portion to the low-pressure suction port side; a bypass-side flow rate adjusting section (14f) that adjusts the flow rate of the refrigerant flowing through the bypass passage; a confluence section (12g) that confluences the flow of the refrigerant flowing out from the bypass-side flow rate adjustment section and the flow of the refrigerant flowing out from the low-stage side pressure reduction section, In a multi-stage hot gas heating mode in which the object to be heated is heated by the heating section, the gas phase refrigerant separated by the hot gas gas-liquid separation section is led to the intermediate pressure intake port side, and the refrigerant flowing out from the confluence section is led to the low pressure intake port side. (Item 2) a compressor (11) that compresses low-pressure refrigerant drawn through a low-pressure suction port (11a) and discharges the refrigerant through a discharge port (11c), and that draws intermediate-pressure refrigerant drawn through an intermediate-pressure suction port (11b) and causes the low-pressure refrigerant to merge with the refrigerant in the process of being compressed; an upstream branch portion (12a) that branches the flow of high-pressure refrigerant discharged from the discharge port; a heating section (13, 30) that heats an object to be heated using one of the high-pressure refrigerants branched at the upstream branch section as a heat source; a downstream branching section (12m) that branches the flow of the refrigerant flowing out from the heating section; a high-stage decompression section (14c) that decompresses one of the refrigerants branched at the downstream branch section; an internal heat exchange section (24) that exchanges heat between the refrigerant flowing out from the high-stage side pressure reduction section and the other refrigerant branched at the downstream side branch section; a low-stage pressure reduction section (14d, 14e) that reduces the pressure of the other refrigerant branched at the downstream branch section and flowing out of the internal heat exchange section; a bypass passage (21f) for guiding the other high-pressure refrigerant branched at the upstream branch portion to the low-pressure suction port side; a bypass-side flow rate adjusting section (14f) that adjusts the flow rate of the refrigerant flowing through the bypass passage; a confluence section (12g) that confluences the flow of the refrigerant flowing out from the bypass-side flow rate adjustment section and the flow of the refrigerant flowing out from the low-stage side pressure reduction section, In a multi-stage hot gas heating mode in which the object to be heated is heated in the heating section, the refrigerant heated in the internal heat exchange section is directed to the intermediate pressure intake port side, and the refrigerant flowing out from the confluence section is directed to the low pressure intake port side. (Item 3) a refrigerant circuit switching unit (22a...22e, 22g) for switching the refrigerant circuit through which the refrigerant circulates, the refrigerant circuit switching unit has an intermediate pressure side opening / closing unit (22c) that opens and closes an intermediate pressure passage (21c) that guides the refrigerant to the intermediate pressure suction port side, 3. The heat pump cycle apparatus according to item 1 or 2, wherein the intermediate pressure side opening / closing unit closes the intermediate pressure passage in a single-stage hot gas heating mode in which the heating unit heats the object to be heated. (Item 4) a target temperature determination unit (60e) that determines a target temperature (TAO) of the object to be heated; an object temperature detection unit (65) that detects an object temperature (TAV) of the object to be heated, 4. The heat pump cycle apparatus according to item 3, wherein the intermediate pressure side opening / closing unit opens the intermediate pressure passage when the object temperature (TAV) is lower than the target temperature (TAO). (Item 5) an outdoor unit high-stage side decompression section (14a) that decompresses the refrigerant; a heating gas-liquid separation section (15a) that separates the refrigerant decompressed in the outdoor unit high-stage side decompression section into gas and liquid; an outdoor unit low-stage side pressure reduction section (14b) that reduces the pressure of the liquid-phase refrigerant separated in the heating gas-liquid separation section; an outdoor heat exchange section (16) for exchanging heat between the refrigerant and outdoor air; a refrigerant circuit switching unit (22a...22d) that switches the refrigerant circuit through which the refrigerant circulates, The refrigerant circuit switching unit Item 1. The heat pump cycle apparatus according to item 1, wherein a refrigerant circuit is switched so that, during an outdoor air heat absorption heating mode in which the heating unit heats the object to be heated, the refrigerant flowing out from the heating unit is guided to the outdoor unit high-stage side pressure reduction unit, the gas phase refrigerant separated in the heating gas-liquid separation unit is guided to the intermediate-pressure suction port side, the refrigerant depressurized in the outdoor unit low-stage side pressure reduction unit is guided to the refrigerant inlet side of the outdoor heat exchange unit, and the refrigerant flowing out from the outdoor heat exchange unit is guided to the low-pressure suction port side. (Item 6) an outdoor unit-side decompression section (14a) that decompresses the refrigerant; an outdoor heat exchange section (16) for exchanging heat between the refrigerant and outdoor air; an outdoor unit passage (21g) for guiding the liquid-phase refrigerant separated in the hot gas gas-liquid separation unit to an inlet side of the outdoor unit side pressure reduction unit; a refrigerant circuit switching unit (22a...22g) that switches the refrigerant circuit through which the refrigerant circulates, The refrigerant circuit switching unit Item 1. The heat pump cycle apparatus according to item 1, wherein the refrigerant circuit is switched so that, during an outdoor air heat absorption heating mode in which the heating unit heats the object to be heated, the gas phase refrigerant separated in the hot gas gas-liquid separation unit is led to the intermediate pressure suction port side, the liquid phase refrigerant separated in the hot gas gas-liquid separation unit is led to the inlet side of the outdoor unit side pressure reduction unit via the outdoor unit passage, the refrigerant decompressed in the outdoor unit side pressure reduction unit is led to the refrigerant inlet side of the outdoor heat exchange unit, and the refrigerant flowing out of the outdoor heat exchange unit is led to the low pressure suction port side. (Item 7) an outdoor unit-side decompression section (14a) that decompresses the refrigerant; an outdoor heat exchange section (16) for exchanging heat between the refrigerant and outdoor air; an outdoor unit passage (21g) for guiding the refrigerant cooled in the internal heat exchanger to an inlet side of the outdoor unit side pressure reducing section; a refrigerant circuit switching unit (22a...22g) that switches the refrigerant circuit through which the refrigerant circulates, The refrigerant circuit switching unit Item 2. The heat pump cycle apparatus according to item 2, wherein, during an outdoor air heat absorption heating mode in which the heating object is heated by the heating unit, the refrigerant circuit is switched so that the refrigerant heated by the internal heat exchange unit is led to the intermediate pressure intake port side, the refrigerant cooled by the internal heat exchange unit is led to the inlet side of the outdoor unit side pressure reduction unit via the outdoor unit passage, and the refrigerant flowing out from the outdoor heat exchange unit is led to the low pressure intake port side. (Item 8) an outdoor heat exchange section (16) for exchanging heat between the refrigerant and outdoor air; a cooling section (18, 20, 40) that evaporates the refrigerant decompressed in the low-stage side decompression section to cool an object to be cooled; a refrigerant circuit switching unit (22a...22g) that switches the refrigerant circuit through which the refrigerant circulates, The refrigerant circuit switching unit Item 1. The heat pump cycle apparatus according to item 1, wherein a refrigerant circuit is switched so that, during a cooling mode in which the cooling unit cools the object to be cooled, the refrigerant flowing out of the heating unit is guided to the refrigerant inlet side of the outdoor heat exchange unit, the refrigerant flowing out of the outdoor heat exchange unit is guided to the inlet side of the high-stage side pressure reduction unit, the gas phase refrigerant separated in the hot gas gas-liquid separation unit is guided to the intermediate-pressure suction port side, the refrigerant decompressed in the low-stage side pressure reduction unit is guided to the refrigerant inlet side of the cooling unit, and the refrigerant flowing out of the cooling unit is guided to the low-pressure suction port side. (Item 9) an outdoor heat exchange section (16) for exchanging heat between the refrigerant and outdoor air; a cooling section (18, 20, 40) that evaporates the refrigerant decompressed in the low-stage side decompression section to cool an object to be cooled; a refrigerant circuit switching unit that switches the refrigerant circuit through which the refrigerant circulates, The refrigerant circuit switching unit Item 3. The heat pump cycle apparatus according to item 2, wherein the refrigerant circuit is switched so that, during a cooling mode in which the cooling unit cools the object to be cooled, the refrigerant flowing out of the heating unit is guided to the refrigerant inlet side of the outdoor heat exchange unit, the refrigerant flowing out of the outdoor heat exchange unit is guided to the inlet side of the downstream branch unit, the refrigerant heated in the internal heat exchange unit is guided to the intermediate-pressure suction port side, the refrigerant decompressed in the low-stage side decompression unit is guided to the refrigerant inlet side of the cooling unit, and the refrigerant flowing out of the cooling unit is guided to the low-pressure suction port side. (Item 10) a high-stage side pressure reduction control unit (60d) for controlling the operation of the high-stage side pressure reduction unit; a target temperature determination unit (60e) that determines a target temperature (TAO) of the object to be heated; an object temperature detection unit (65) that detects an object temperature (TAV) of the object to be heated, The heat pump cycle apparatus according to any one of items 1, 5, 6, and 8, wherein the high-stage side pressure reduction control unit increases the throttle opening of the high-stage side pressure reduction unit when the object temperature (TAV) is lower than the target temperature (TAO) during the multi-stage hot gas heating mode. [Explanation of symbols]

[0405] 1, 1a Vehicle air conditioning system (heat pump cycle system) 11 Compressor 12a First three-way joint (upstream branch) 12g 7th three-way joint (junction) 12m 13th three-way joint (downstream branch) 13 Water-refrigerant heat exchanger (heating section) 14c High-stage expansion valve (high-stage pressure reducing section) 14d, 14e Cooling expansion valve (low stage side pressure reducing section), cooling pressure reducing section (low stage side pressure reducing section) 14f Bypass side flow rate adjustment valve (bypass side flow rate adjustment part) 21F Bypass Passage 24 Internal heat exchanger (internal heat exchange section) 30 High temperature side heat medium circuit (heating section)

Claims

1. a compressor (11) that compresses a low-pressure refrigerant drawn through a low-pressure suction port (11a) and discharges it from a discharge port (11c), and that draws an intermediate-pressure refrigerant drawn through an intermediate-pressure suction port (11b) and causes the low-pressure refrigerant in the compression process to merge; an upstream branch portion (12a) that branches the flow of the high-pressure refrigerant discharged from the discharge port; a heating section (13, 30) that heats an object to be heated using one of the high-pressure refrigerants branched at the upstream branch section as a heat source; a high-stage pressure reducing section (14c) that reduces the pressure of the refrigerant flowing out from the heating section; a hot gas gas-liquid separation section (15b) for separating the refrigerant flowing out from the high-stage side pressure reduction section into gas and liquid; a low-stage pressure reducing section (14d, 14e) that reduces the pressure of the liquid-phase refrigerant separated in the hot gas gas-liquid separation section; a bypass passage (21f) for guiding the other high-pressure refrigerant branched at the upstream branch portion to the low-pressure suction port side; a bypass-side flow rate adjusting section (14f) that adjusts the flow rate of the refrigerant flowing through the bypass passage; a confluence section (12g) that confluences the flow of the refrigerant flowing out from the bypass-side flow rate adjustment section and the flow of the refrigerant flowing out from the low-stage side pressure reduction section, In a multi-stage hot gas heating mode in which the object to be heated is heated by the heating section, the gas phase refrigerant separated by the hot gas gas-liquid separation section is led to the intermediate pressure intake port side, and the refrigerant flowing out from the confluence section is led to the low pressure intake port side.

2. a compressor (11) that compresses a low-pressure refrigerant drawn through a low-pressure suction port (11a) and discharges it from a discharge port (11c), and that draws an intermediate-pressure refrigerant drawn through an intermediate-pressure suction port (11b) and causes the low-pressure refrigerant in the compression process to merge; an upstream branch portion (12a) that branches the flow of the high-pressure refrigerant discharged from the discharge port; a heating section (13, 30) that heats an object to be heated using one of the high-pressure refrigerants branched at the upstream branch section as a heat source; a downstream branching section (12m) that branches the flow of the refrigerant flowing out from the heating section; a high-stage pressure reduction section (14c) that reduces the pressure of one of the refrigerants branched at the downstream branch section; an internal heat exchange section (24) that exchanges heat between the refrigerant flowing out from the high-stage side pressure reduction section and the other refrigerant branched at the downstream side branch section; a low-stage decompression section (14d, 14e) that decompresses the other refrigerant branched at the downstream branch section and flowing out of the internal heat exchange section; a bypass passage (21f) for guiding the other high-pressure refrigerant branched at the upstream branch portion to the low-pressure suction port side; a bypass-side flow rate adjusting section (14f) that adjusts the flow rate of the refrigerant flowing through the bypass passage; a confluence section (12g) that confluences the flow of the refrigerant flowing out from the bypass-side flow rate adjustment section and the flow of the refrigerant flowing out from the low-stage side pressure reduction section, In a multi-stage hot gas heating mode in which the object to be heated is heated in the heating section, the refrigerant heated in the internal heat exchange section is directed to the intermediate pressure intake port side, and the refrigerant flowing out from the confluence section is directed to the low pressure intake port side.

3. a refrigerant circuit switching unit (22a...22e, 22g) for switching a refrigerant circuit through which the refrigerant circulates, the refrigerant circuit switching unit has an intermediate pressure side opening / closing unit (22c) that opens and closes an intermediate pressure passage (21c) that guides the refrigerant to the intermediate pressure suction port side, The heat pump cycle apparatus according to claim 1 or 2, wherein the intermediate pressure side opening / closing unit closes the intermediate pressure passage in a single-stage hot gas heating mode in which the heating unit heats the object to be heated.

4. a target temperature determination unit (60e) for determining a target temperature (TAO) of the object to be heated; an object temperature detection unit (65) that detects an object temperature (TAV) of the object to be heated, The heat pump cycle device according to claim 3 , wherein the intermediate pressure side opening / closing unit opens the intermediate pressure passage when the object temperature (TAV) is lower than the target temperature (TAO).

5. an outdoor unit high-stage side decompression section (14a) that decompresses the refrigerant; a heating gas-liquid separation section (15a) that separates the refrigerant decompressed in the outdoor unit high-stage side decompression section into gas and liquid; an outdoor unit low-stage side pressure reducing section (14b) that reduces the pressure of the liquid phase refrigerant separated in the heating gas-liquid separation section; an outdoor heat exchange section (16) for exchanging heat between the refrigerant and outdoor air; a refrigerant circuit switching unit (22a...22d) that switches the refrigerant circuit through which the refrigerant circulates, The refrigerant circuit switching unit 2. The heat pump cycle device according to claim 1, wherein the refrigerant circuit is switched so that, during an outdoor air heat absorption heating mode in which the heating unit heats the object to be heated, the refrigerant flowing out from the heating unit is led to the outdoor unit high-stage pressure reduction unit, the gas phase refrigerant separated in the heating gas-liquid separation unit is led to the intermediate-pressure suction port side, the refrigerant decompressed in the outdoor unit low-stage pressure reduction unit is led to the refrigerant inlet side of the outdoor heat exchange unit, and the refrigerant flowing out from the outdoor heat exchange unit is led to the low-pressure suction port side.

6. an outdoor unit side decompression section (14a) that decompresses the refrigerant; an outdoor heat exchange section (16) for exchanging heat between the refrigerant and outdoor air; an outdoor unit passage (21g) for guiding the liquid-phase refrigerant separated in the hot gas gas-liquid separation unit to an inlet side of the outdoor unit side pressure reduction unit; a refrigerant circuit switching unit (22a...22g) that switches the refrigerant circuit through which the refrigerant circulates, The refrigerant circuit switching unit 2. The heat pump cycle device according to claim 1, wherein the refrigerant circuit is switched so that, during an outdoor air heat absorption heating mode in which the heating unit heats the object to be heated, the gas phase refrigerant separated in the hot gas gas-liquid separation unit is led to the intermediate pressure intake side, the liquid phase refrigerant separated in the hot gas gas-liquid separation unit is led to the inlet side of the outdoor unit side pressure reduction unit through the outdoor unit passage, the refrigerant decompressed in the outdoor unit side pressure reduction unit is led to the refrigerant inlet side of the outdoor heat exchange unit, and the refrigerant flowing out from the outdoor heat exchange unit is led to the low pressure intake side.

7. an outdoor unit side decompression section (14a) that decompresses the refrigerant; an outdoor heat exchange section (16) for exchanging heat between the refrigerant and outdoor air; an outdoor unit passage (21g) for guiding the refrigerant cooled in the internal heat exchanger to an inlet side of the outdoor unit side pressure reducing section; a refrigerant circuit switching unit (22a...22g) that switches the refrigerant circuit through which the refrigerant circulates, The refrigerant circuit switching unit 3. The heat pump cycle device according to claim 2, wherein the refrigerant circuit is switched so that, during an outdoor air heat absorption heating mode in which the heating unit heats the object to be heated, the refrigerant heated in the internal heat exchange unit is led to the intermediate pressure intake port side, the refrigerant cooled in the internal heat exchange unit is led to the inlet side of the outdoor unit side pressure reduction unit via the outdoor unit passage, and the refrigerant flowing out from the outdoor heat exchange unit is led to the low pressure intake port side.

8. an outdoor heat exchange section (16) for exchanging heat between the refrigerant and outdoor air; a cooling section (18, 20, 40) that evaporates the refrigerant decompressed in the low-stage side decompression section to cool an object to be cooled; a refrigerant circuit switching unit (22a...22g) that switches the refrigerant circuit through which the refrigerant circulates, The refrigerant circuit switching unit 2. The heat pump cycle device according to claim 1, wherein the refrigerant circuit is switched so that, during a cooling mode in which the object to be cooled is cooled by the cooling section, the refrigerant flowing out of the heating section is led to the refrigerant inlet side of the outdoor heat exchange section, the refrigerant flowing out of the outdoor heat exchange section is led to the inlet side of the high-stage side pressure reduction section, the gas phase refrigerant separated in the hot gas gas-liquid separation section is led to the intermediate pressure intake side, the refrigerant decompressed in the low-stage side pressure reduction section is led to the refrigerant inlet side of the cooling section, and the refrigerant flowing out of the cooling section is led to the low-pressure intake side.

9. an outdoor heat exchange section (16) for exchanging heat between the refrigerant and outdoor air; a cooling section (18, 20, 40) that evaporates the refrigerant decompressed in the low-stage side decompression section to cool an object to be cooled; a refrigerant circuit switching unit that switches the refrigerant circuit through which the refrigerant circulates, The refrigerant circuit switching unit 3. The heat pump cycle device according to claim 2, wherein the refrigerant circuit is switched so that, during a cooling mode in which the cooling unit cools the object to be cooled, the refrigerant flowing out of the heating unit is led to the refrigerant inlet side of the outdoor heat exchange unit, the refrigerant flowing out of the outdoor heat exchange unit is led to the inlet side of the downstream branch unit, the refrigerant heated in the internal heat exchange unit is led to the intermediate pressure intake side, the refrigerant decompressed in the low stage pressure reduction unit is led to the refrigerant inlet side of the cooling unit, and the refrigerant flowing out of the cooling unit is led to the low pressure intake side.

10. a high-stage side pressure reduction control unit (60d) for controlling the operation of the high-stage side pressure reduction unit; a target temperature determination unit (60e) for determining a target temperature (TAO) of the object to be heated; an object temperature detection unit (65) that detects an object temperature (TAV) of the object to be heated, The heat pump cycle device according to claim 1, wherein the high-stage pressure reduction control unit increases the throttle opening of the high-stage pressure reduction unit when the object temperature (TAV) is lower than the target temperature (TAO) during the multi-stage hot gas heating mode.

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