Heat pump cycle equipment

Abstract

This heat pump cycle device comprises a compressor (11), a branching part (12a), a heating unit (13), a heating unit-side decompression unit (14a, 14c), a bypass passage (21c), a bypass-side flow rate adjustment unit (14d), a passage (21c) merging part (12f), and an adjustment capacity determination unit (S3). Furthermore, when the adjustment capacity determination unit (S3) determines that the flow rate adjustment capacity of one of the heating unit-side decompression unit (14a, 14c) and the bypass-side flow rate adjustment unit (14d) is equal to or less than a reference adjustment ability, the throttle opening of the other unit is set to be equal to or less than the maximum opening.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2021-197801 filed on December 6, 2021, the contents of which are incorporated herein by reference. [Technical field]

[0002] The present disclosure relates to a heat pump cycle apparatus in which refrigerants having different enthalpies are mixed and sucked into a compressor. [Background technology]

[0003] Conventionally, a heat pump cycle device applied to a vehicle air conditioner is disclosed in Patent Document 1. The heat pump cycle device of Patent Document 1 operates in a hot gas heating mode to heat the vehicle interior when the outside air temperature is extremely low.

[0004] In the hot gas heating mode of Patent Document 1, the refrigerant discharged from the compressor is made to flow into a branching section. Then, one of the refrigerants branched at the branching section is made to flow into a heating section. In the heating section, the refrigerant is heat-exchanged with the blown air blown into the vehicle cabin, thereby heating the blown air. Furthermore, the refrigerant flowing out of the heating section is depressurized in a heating section side depressurization section.

[0005] The other refrigerant branched at the branching section is caused to flow into the bypass passage. The refrigerant flowing into the bypass passage is then depressurized by the bypass-side flow control valve. The refrigerant depressurized at the heating section depressurization section and the refrigerant depressurized at the bypass-side flow control valve are then mixed in the mixing section and drawn into the compressor.

[0006] That is, in the heat pump cycle device of Patent Document 1, when operation in the hot gas heating mode is performed, a refrigerant circuit is switched to one in which refrigerants with different enthalpies are mixed and sucked into the compressor. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-156567 Summary of the Invention

[0008] In the refrigerant circuit in the hot gas heating mode of Patent Document 1, the workload of the compressor needs to be appropriately adjusted to realize appropriate heating of the vehicle interior. At the same time, the throttle opening of the heating section side pressure reducing section and the bypass side flow control valve needs to be appropriately adjusted so that the state of the refrigerant sucked into the compressor is appropriate. The reason is that if the state of the refrigerant sucked into the compressor is not maintained in an appropriate state, it will have a negative effect on the durable life of the compressor.

[0009] In response to this, Patent Document 1 discloses that, during hot gas heating mode, the operation of the heating section side pressure reduction section and the bypass side flow control valve is controlled so that the superheat degree of the suctioned refrigerant approaches a predetermined reference superheat degree.

[0010] However, in an actual heat pump cycle device, the refrigerant flow rate adjustment range in the heating unit-side pressure reduction unit and the bypass-side flow rate adjustment range are different, so if the throttle opening of either the heating unit-side pressure reduction unit or the bypass-side flow rate adjustment valve approaches a fully open state and the flow rate adjustment capability decreases, it may become impossible to maintain the state of the suctioned refrigerant in an appropriate state.

[0011] Therefore, in the heat pump cycle device of Patent Document 1, there is a possibility that the compressor cannot be reliably protected in the hot gas heating mode.

[0012] In view of the above, an object of the present disclosure is to provide a heat pump cycle apparatus that can reliably protect a compressor even when refrigerants with different enthalpies are mixed and sucked into the compressor.

[0013] A heat pump cycle apparatus according to a first aspect of the present disclosure includes a compressor, a branching section, a heating section, a heating section side pressure reducing section, a bypass passage, a bypass side flow rate adjusting section, a mixing section, a target temperature determining section, and an adjustment capability determining section.

[0014] The compressor compresses and discharges the refrigerant. The branching section branches the flow of the discharged refrigerant discharged from the compressor. The heating section heats an object to be heated using one of the discharged refrigerants branched at the branching section as a heat source. The heating section side decompression section decompresses the refrigerant flowing out from the heating section. The bypass passage is a refrigerant passage that leads the other discharged refrigerant branched at the branching section to the suction port side of the compressor. The bypass side flow rate adjustment section adjusts the flow rate of the refrigerant flowing through the bypass passage. The mixing section mixes the refrigerant flowing out from the bypass side flow rate adjustment section and the refrigerant flowing out from the heating section side decompression section, and causes the refrigerant to flow out to the suction port side of the compressor. The target temperature determination section determines a target temperature that is a target value of the object temperature of the object to be heated heated by the heating section. The adjustment capacity determination section determines whether the flow rate adjustment capacity of one of the heating section side decompression section and the bypass side flow rate adjustment section is equal to or less than a predetermined reference adjustment capacity.

[0015] Then, the operation of at least one of the heating section side pressure reduction section and the bypass side flow rate adjustment section is controlled so that the dryness of the suctioned refrigerant sucked into the compressor approaches a predetermined standard dryness as the object temperature approaches the target temperature, or so that the superheat of the suctioned refrigerant approaches a predetermined standard superheat as the object temperature approaches the target temperature.

[0016] Furthermore, when the adjustment capacity determination unit determines that the flow rate adjustment capacity of one of the heating unit side pressure reduction unit and the bypass side flow rate adjustment unit is equal to or lower than the reference adjustment capacity, the throttle opening of the other of the heating unit side pressure reduction unit and the bypass side flow rate adjustment unit is adjusted to Reduce do.

[0017] According to this, when the adjustment capacity determination unit (S12) determines that the flow rate adjustment capacity of one of the heating unit side pressure reduction units (14a, 14c) and the bypass side flow rate adjustment unit (14d) is equal to or lower than the reference adjustment capacity, the throttle opening of the other of the heating unit side pressure reduction units (14a, 14c) and the bypass side flow rate adjustment unit (14d) is adjusted to Reduce do.

[0018] Therefore, when it becomes difficult to increase the flow rate of the refrigerant flowing into the mixing section from one side of the heating section side pressure reduction section and the bypass side flow rate adjustment section, the flow rate of the refrigerant flowing into the mixing section from the other side of the heating section side pressure reduction section and the bypass side flow rate adjustment section can be restricted.

[0019] As a result, it is possible to prevent the state of the sucked refrigerant from becoming a gas-liquid two-phase refrigerant with an unnecessarily low dryness or a gas-phase refrigerant with an unnecessarily high superheat degree. In other words, even in a heat pump cycle device in which refrigerants with different enthalpies are mixed in the mixing section and sucked into the compressor, it is possible to reliably protect the compressor.

[0020] Here, the flow rate adjustment capability can be defined as the ratio of the amount of change in flow rate to the amount of change in the throttle opening.

[0021] A heat pump cycle apparatus according to a second aspect of the present disclosure includes a compressor, a branching section, a heating section, a heating section-side pressure reducing section, a bypass passage, a bypass-side flow rate adjusting section, and a mixing section.

[0022] The compressor compresses and discharges the refrigerant. The branching section branches the flow of the discharged refrigerant discharged from the compressor. The heating section heats an object to be heated using one of the discharged refrigerants branched at the branching section as a heat source. The heating section side decompression section decompresses the refrigerant flowing out from the heating section. The bypass passage is a refrigerant passage that guides the other discharged refrigerant branched at the branching section to the suction port side of the compressor. The bypass side flow rate adjustment section adjusts the flow rate of the refrigerant flowing through the bypass passage. The mixing section mixes the refrigerant flowing out from the bypass side flow rate adjustment section and the refrigerant flowing out from the heating section side decompression section, and causes the mixed refrigerant to flow out to the suction port side of the compressor.

[0023] The ratio of the throttle opening of the heating section side pressure reduction section to the throttle opening of the bypass side flow rate adjustment section is adjusted so that the dryness of the suctioned refrigerant sucked into the compressor approaches a predetermined standard dryness, or so that the superheat of the suctioned refrigerant approaches a predetermined standard superheat.

[0024] According to this, the opening ratio is adjusted so that the dryness of the suctioned refrigerant approaches the reference dryness or the superheat of the suctioned refrigerant approaches the reference superheat. Therefore, the throttle opening of the heating section-side pressure reducing section and the throttle opening of the bypass-side flow rate adjusting section can be changed within a range in which the state of the suctioned refrigerant is appropriate, regardless of the refrigerant discharge capacity of the compressor.

[0025] As a result, it is possible to prevent the state of the sucked refrigerant from becoming a gas-liquid two-phase refrigerant with an unnecessarily low dryness or a gas-phase refrigerant with an unnecessarily high superheat degree. In other words, even in a heat pump cycle device in which refrigerants with different enthalpies are mixed in the mixing section and sucked into the compressor, it is possible to reliably protect the compressor. [Brief description of the drawings]

[0026] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Figure 1] 1 is a schematic overall configuration diagram of a vehicle air conditioner according to a first embodiment. [Diagram 2] FIG. 1 is a schematic configuration diagram of an indoor air conditioning unit according to a first embodiment. [Diagram 3] 2 is a block diagram showing an electric control unit of the vehicle air conditioner of the first embodiment. FIG. [Figure 4] 4 is a flowchart of a main routine of a control program according to the first embodiment. [Diagram 5] FIG. 2 is a schematic overall configuration diagram showing a flow of a refrigerant in a hot gas heating mode of the heat pump cycle of the first embodiment. [Figure 6]5 is a flowchart of a subroutine of a control program according to the first embodiment. [Figure 7] FIG. 4 is a Mollier diagram showing changes in the state of a refrigerant in a hot gas heating mode of the heat pump cycle of the first embodiment. [Figure 8] FIG. 2 is a schematic overall configuration diagram showing a flow of a refrigerant in a hot gas dehumidification heating mode of the heat pump cycle of the first embodiment. [Figure 9] 6 is a flowchart of another subroutine of the control program according to the first embodiment. [Figure 10] FIG. 4 is a Mollier diagram showing a change in state of a refrigerant in a hot gas dehumidification heating mode of the heat pump cycle of the first embodiment. [Figure 11] FIG. 2 is a schematic overall configuration diagram showing a flow of a refrigerant in a hot gas serial dehumidification heating mode of the heat pump cycle of the first embodiment. [Figure 12] FIG. 4 is a Mollier diagram showing a change in state of a refrigerant in a hot gas serial dehumidification heating mode of the heat pump cycle of the first embodiment. [Figure 13] 10 is a flowchart of a subroutine of a control program according to a second embodiment. [Figure 14] FIG. 13 is a control characteristic diagram for controlling an opening ratio in the third embodiment. [Figure 15] FIG. 11 is a schematic overall configuration diagram of a vehicle air conditioner according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, a number of embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be used to designate parts corresponding to matters described in the preceding embodiment, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other embodiments described previously may be applied to other parts of the configuration. In addition to combinations of parts that are specifically indicated as being possible 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.

[0028] (First embodiment) A first embodiment of a heat pump cycle device according to the present disclosure will be described with reference to Figs. 1 to 12. In this embodiment, the heat pump cycle device according to the present disclosure is applied to a vehicle air conditioner 1 mounted on an electric vehicle. An electric vehicle is a vehicle that obtains driving force for traveling from an electric motor. The vehicle air conditioner 1 performs air conditioning of 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.

[0029] 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 in-vehicle devices that operate electrically. 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.

[0030] The battery 70 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. Of course, the on-board equipment that is the subject of temperature adjustment by the vehicle air conditioner 1 is not limited to the battery 70.

[0031] The vehicle air conditioner 1 includes a heat pump cycle 10, a low-temperature side heat medium circuit 40, an interior air conditioning unit 50, a control device 60, and the like.

[0032] First, a heat pump cycle 10 will be described with reference to Fig. 1. The heat pump cycle 10 is a vapor compression type refrigeration cycle that adjusts the temperature of the air blown into the vehicle cabin and the low-temperature side heat medium circulating in a low-temperature side heat medium circuit 40. The heat pump cycle 10 is configured to be able to switch the refrigerant circuit according to various operation modes described later in order to perform air conditioning in the vehicle cabin and temperature adjustment of on-board equipment.

[0033] 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. The refrigerant is mixed with refrigerant oil for lubricating the compressor 11. The refrigerant oil is PAG oil (i.e., polyalkylene glycol oil) that is compatible with liquid-phase refrigerant. A portion of the refrigerant oil circulates through the heat pump cycle 10 together with the refrigerant.

[0034] The compressor 11 draws in, compresses, and discharges the refrigerant in the heat pump cycle 10. The compressor 11 is an electric compressor that uses an electric motor to rotate a fixed-capacity compression mechanism having a fixed discharge capacity. The refrigerant discharge capacity (i.e., rotation speed) of the compressor 11 is controlled by a control signal output from a control device 60, which will be described later.

[0035] The compressor 11 is disposed in a drive unit room formed in the front side of the vehicle interior. The drive unit room forms a space in which at least some of the devices used for generating and adjusting the driving force for running the vehicle (for example, an electric motor for running) are disposed.

[0036] The inlet side of a first three-way joint 12a is connected to the discharge port of the compressor 11. The first three-way joint 12a has three inlets and outlets that communicate with each other. As the first three-way joint 12a, a joint part formed by joining multiple pipes or a joint part formed by providing multiple refrigerant passages in a metal block or a resin block can be used.

[0037] Furthermore, the heat pump cycle 10 includes a second three-way joint 12b to a sixth three-way joint 12f, as described below. The second three-way joint 12b to the sixth three-way joint 12f have the same basic configuration as the first three-way joint 12a. The basic configuration of each three-way joint described in the embodiment described below is also the same as the first three-way joint 12a.

[0038] These three-way joints branch the flow of the refrigerant when one of the three inlet / outlets is used as an inlet and the remaining two are used as outlets. Also, when two of the three inlet / outlets are used as inlet ports and the remaining one is used as an outlet, the refrigerant flows are joined together. Therefore, the first three-way joint 12a is a branching section that branches the flow of the refrigerant discharged from the compressor 11.

[0039] One of the outlets of the first three-way joint 12a is connected to an inlet side of the refrigerant passage of the indoor condenser 13. One of the inlet sides of the sixth three-way joint 12f is connected to the other of the outlets of the first three-way joint 12a. The refrigerant passage extending from the other of the outlets of the first three-way joint 12a to one of the inlet sides of the sixth three-way joint 12f is a bypass passage 21c. A bypass-side flow rate control valve 14d is disposed in the bypass passage 21c.

[0040] The bypass-side flow rate control valve 14d is a pressure reducing part on the bypass passage side that reduces the pressure of the discharged refrigerant flowing out from the other outlet of the first three-way joint 12a (i.e., the other discharged refrigerant branched at the first three-way joint 12a) during a hot gas heating mode, etc., which will be described later. The bypass-side flow rate control valve 14d is a bypass-side flow rate control part that adjusts the flow rate (mass flow rate) of the refrigerant flowing through the bypass passage 21c.

[0041] The bypass-side flow rate control valve 14d is an electric variable throttle mechanism having a valve body that changes the throttle opening and an electric actuator (specifically, a stepping motor) as a drive unit that displaces the valve body. The operation of the bypass-side flow rate control valve 14d is controlled by a control pulse output from the control device 60.

[0042] The bypass-side flow rate control valve 14d has a full-open function that functions simply as a refrigerant passage without exerting any refrigerant pressure reduction or flow rate adjustment action by fully opening the throttle valve 14d, and a full-close function that closes the refrigerant passage by fully closing the throttle valve 14d.

[0043] Furthermore, as described below, the heat pump cycle 10 includes a heating expansion valve 14a, a cooling expansion valve 14b, and a cooling expansion valve 14c. The heating expansion valve 14a, the cooling expansion valve 14b, and the cooling expansion valve 14c have the same basic configuration as the bypass-side flow control valve 14d.

[0044] The heating expansion valve 14a, the cooling expansion valve 14b, the cooling expansion valve 14c, and the bypass side flow rate control valve 14d can switch the refrigerant circuit by exerting the above-mentioned fully closed function. Therefore, the heating expansion valve 14a, the cooling expansion valve 14b, the cooling expansion valve 14c, and the bypass side flow rate control valve 14d also function as a refrigerant circuit switching unit.

[0045] Of course, the heating expansion valve 14a, the cooling expansion valve 14b, the cooling expansion valve 14c, and the bypass side flow rate control valve 14d 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 throttle passage. In this case, each on-off valve serves as a refrigerant circuit switching unit.

[0046] The indoor condenser 13 is disposed in an air conditioning case 51 of the indoor air conditioning unit 50, which will be described later. The indoor condenser 13 is a heating heat exchanger that exchanges heat between the discharged refrigerant flowing out from one outlet of the first three-way joint 12a (i.e., one of the discharged refrigerant branched at the first three-way joint 12a) and the blown air that has passed through an indoor evaporator 18, which will be described later. The indoor condenser 13 releases heat from the discharged refrigerant to the blown air, heating the blown air.

[0047] Therefore, the indoor condenser 13 is a heating section that heats the blown air, which is an object to be heated, using one of the discharged refrigerant branches at the first three-way joint 12a as a heat source.

[0048] The inlet side of the second three-way joint 12b is connected to the outlet of the refrigerant passage of the indoor condenser 13. The inlet side of the heating expansion valve 14a is connected to one of the outlets of the second three-way joint 12b. The inlet side of one of the four-way joints 12x is connected to the other outlet of the second three-way joint 12b. The refrigerant passage extending from the other outlet of the second three-way joint 12b to one of the inlets of the four-way joint 12x is the dehumidification passage 21a.

[0049] A dehumidification on-off valve 22a is disposed in the dehumidification passage 21a. The dehumidification on-off valve 22a is an on-off valve that opens and closes the dehumidification passage 21a. The dehumidification on-off valve 22a is an electromagnetic valve whose opening and closing operation is controlled by a control voltage output from the control device 60. The dehumidification on-off valve 22a can switch the refrigerant circuit by opening and closing the dehumidification passage 21a. Therefore, the dehumidification on-off valve 22a is a refrigerant circuit switching unit.

[0050] The four-way joint 12x is a joint part having four inlet and outlet ports that communicate with each other. A joint part formed in the same manner as the above-mentioned three-way joint can be used as the four-way joint 12x. A joint part formed by combining two three-way joints may also be used as the four-way joint 12x.

[0051] The heating expansion valve 14a is a pressure reducing section on the outdoor heat exchanger side that reduces the pressure of the refrigerant flowing into the outdoor heat exchanger 15 during a heating mode, which will be described later, etc. Furthermore, the heating expansion valve 14a is a flow rate adjusting section on the outdoor heat exchanger side that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the outdoor heat exchanger 15.

[0052] The outlet of the heating expansion valve 14a is connected to the refrigerant inlet side of the exterior heat exchanger 15. The exterior heat exchanger 15 is an exterior heat exchanger that exchanges heat between the refrigerant flowing out of the heating expansion valve 14a and the outside air blown by an outside air fan (not shown). The exterior heat exchanger 15 is disposed on the front side of the drive unit compartment. Therefore, when the vehicle is traveling, the traveling wind that flows into the drive unit compartment through the grill can be applied to the exterior heat exchanger 15.

[0053] An inlet side of a third three-way joint 12c is connected to a refrigerant outlet of the outdoor heat exchanger 15. Another inlet side of a four-way joint 12x is connected to one outlet side of the third three-way joint 12c via a first check valve 16a. One inlet side of a fourth three-way joint 12d is connected to the other outlet side of the third three-way joint 12c. The refrigerant passage that runs from the other outlet side of the third three-way joint 12c to one inlet side of the fourth three-way joint 12d is a heating passage 21b.

[0054] A heating on-off valve 22b is disposed in the heating passage 21b. The heating on-off valve 22b is an on-off valve that opens and closes the heating passage 21b. The heating on-off valve 22b has a basic configuration similar to that of the dehumidification on-off valve 22a. Therefore, the heating on-off valve 22b is a refrigerant circuit switching unit. In addition, the basic configurations of the on-off valves described in the embodiments described below are also similar to that of the dehumidification on-off valve 22a.

[0055] The first check valve 16a allows the refrigerant to flow from the third three-way joint 12c side to the four-way joint 12x side and prohibits the refrigerant from flowing from the four-way joint 12x side to the third three-way joint 12c side.

[0056] One outlet of the four-way joint 12x is connected to the refrigerant inlet side of the indoor evaporator 18 via a cooling expansion valve 14b. The cooling expansion valve 14b is a pressure reducing section on the indoor evaporator side that reduces the pressure of the refrigerant flowing into the indoor evaporator 18 during a cooling mode, which will be described later, etc. Furthermore, the cooling expansion valve 14b is a flow rate adjusting section on the indoor evaporator side that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the indoor evaporator 18.

[0057] 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 a heat exchanger that exchanges heat between the low-pressure refrigerant decompressed by the cooling expansion valve 14b and the blown air blown from the interior blower 52 toward the vehicle interior. The interior evaporator 18 evaporates the low-pressure refrigerant to exert a heat absorption effect, thereby cooling the blown air.

[0058] One inlet side of a fifth three-way joint 12e is connected via a second check valve 16b to a refrigerant outlet of the indoor evaporator 18. The second check valve 16b allows the refrigerant to flow from the refrigerant outlet side of the indoor evaporator 18 to the fifth three-way joint 12e side, and prohibits the refrigerant from flowing from the fifth three-way joint 12e side to the refrigerant outlet side of the indoor evaporator 18.

[0059] Another outlet of the four-way joint 12x is connected to the inlet side of the refrigerant passage of the chiller 20 via a cooling expansion valve 14c. The cooling expansion valve 14c is a chiller-side pressure reducing section that reduces the pressure of the refrigerant flowing into the chiller 20 in a cooling and air-conditioning mode or a hot gas heating mode, which will be described later. Furthermore, the cooling expansion valve 14c is a chiller-side flow rate adjusting section that adjusts the flow rate (mass flow rate) of the refrigerant flowing into the chiller 20.

[0060] The chiller 20 is a heat exchanger that exchanges heat between the low-pressure refrigerant decompressed by the cooling expansion valve 14c and the low-temperature side heat medium circulating through the low-temperature side heat medium circuit 40. The chiller 20 is capable of cooling the low-temperature side heat medium by evaporating the low-pressure refrigerant to exert a heat absorption effect. Also, the low-temperature side heat medium can be heated by dissipating heat possessed by the low-pressure refrigerant to the low-temperature side heat medium.

[0061] The other inlet side of sixth three-way joint 12f is connected to the outlet of the refrigerant passage of chiller 20. The other inlet side of fifth three-way joint 12e is connected to the outlet of sixth three-way joint 12f. The other inlet side of fourth three-way joint 12d is connected to the outlet of fifth three-way joint 12e.

[0062] The inlet side of the accumulator 23 is connected to the outlet of the fourth three-way joint 12d. The accumulator 23 is a low-pressure side gas-liquid separator that separates the refrigerant that has flowed into it into gas and liquid and stores the excess liquid-phase refrigerant in the cycle. The gas-phase refrigerant outlet of the accumulator 23 is connected to the suction port side of the compressor 11. The accumulator 23 has an oil return hole for returning refrigeration oil contained in the separated liquid-phase refrigerant to the compressor 11 together with the gas-phase refrigerant.

[0063] 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 the low-temperature side heat medium. In this embodiment, an ethylene glycol aqueous solution 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 cooling water passage 70a of the battery 70, a heat medium passage of the chiller 20, etc.

[0064] The low-temperature side pump 41 is a low-temperature side heat medium pumping section 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 low-temperature side pump 41 is an electric pump whose rotation speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 60. The inlet side of the cooling water passage 70a of the battery 70 is connected to the outlet side of the heat medium passage of the chiller 20.

[0065] The cooling water passage 70a of the battery 70 is a cooling water passage formed to cool the battery 70 by circulating the low-temperature side heat medium cooled by the chiller 20. The cooling water passage 70a is formed inside a dedicated battery case that houses a plurality of stacked battery cells.

[0066] 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.

[0067] Next, the interior air conditioning unit 50 will be described with reference to Fig. 2. The interior air conditioning unit 50 is a unit that integrates a number of components to blow air adjusted to an appropriate temperature for air conditioning the vehicle interior to an appropriate location within the vehicle interior. The interior air conditioning unit 50 is disposed inside the instrument panel at the front end of the vehicle interior.

[0068] The indoor air conditioning unit 50 is formed by accommodating an indoor blower 52, an indoor evaporator 18, an indoor condenser 13, etc. in an air conditioning case 51 that forms an air passage for the blown air. The air conditioning case 51 is molded from a resin (e.g., polypropylene) that has a certain degree of elasticity and excellent strength.

[0069] 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.

[0070] 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 drawn 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.

[0071] The indoor evaporator 18 and the indoor condenser 13 are disposed downstream in the flow of air blown by the indoor blower 52. The indoor evaporator 18 is disposed upstream in the flow of air blown by the indoor condenser 13. A cold air bypass passage 55 is formed in the air conditioning case 51, which allows the blown air after passing through the indoor evaporator 18 to flow around the indoor condenser 13.

[0072] An air mix door 54 is disposed downstream of the indoor evaporator 18 in the air conditioning case 51 in terms of the blown air flow and upstream of the indoor condenser 13 and the cold air bypass passage 55 in terms of the blown air flow.

[0073] The air mix door 54 adjusts the ratio of the volume of the blown air passing through the indoor condenser 13 side to the volume of the blown air passing through the cold air bypass passage 55, among the blown air after passing through the indoor 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.

[0074] A mixing space 56 is disposed downstream of the indoor condenser 13 and the cold air bypass passage 55 in the flow of blown air. The mixing space 56 is a space in which the blown air heated by the indoor condenser 13 and the blown air that has passed through the cold air bypass passage 55 and has not been heated are mixed.

[0075] Therefore, in the interior air conditioning unit 50, the temperature of the blown air (i.e., the conditioned air) mixed in the mixing space 56 and blown into the vehicle interior can be adjusted by adjusting the opening degree of the air mix door 54. The air mix door 54 in this embodiment is an air flow rate adjustment unit that adjusts the flow rate of the blown air that is heat exchanged in the interior condenser 13.

[0076] At the most downstream part of the blown air flow of the air conditioning case 51, a plurality of openings (not shown) are formed for blowing out the conditioned air toward various parts in the vehicle cabin. A blow mode door (not shown) for opening and closing each of the openings is disposed in each of the openings. The operation of the actuator for driving the blow mode door is controlled by a control signal output from the control device 60.

[0077] Therefore, in the interior air conditioning unit 50, by switching the opening hole that the blowing 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 cabin.

[0078] Next, the electric control unit of this embodiment will be described. 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 processing based on a control program stored in the ROM. Then, the control device 60 controls the operation of various control target devices 11, 14a to 14d, 22a, 22b, 41, 52, 53, etc. connected to the output side based on the calculation and processing results.

[0079] As shown in the block diagram of FIG. 3, a group of control sensors are connected to the input side of the control device 60, such as an inside air temperature sensor 61a, an outside air temperature sensor 61b, a solar radiation sensor 61c, a discharge refrigerant temperature sensor 62a, a high-pressure side refrigerant temperature and pressure sensor 62b, an evaporator temperature sensor 62c, an evaporator outlet side refrigerant temperature sensor 62d, a chiller side refrigerant temperature and pressure sensor 62e, an intake refrigerant temperature and pressure sensor 62f, a low-temperature side heat medium temperature sensor 63a, a battery temperature sensor 64 and an air conditioning air temperature sensor 65.

[0080] 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 irradiated into the vehicle cabin.

[0081] The discharge refrigerant temperature sensor 62a is a discharge refrigerant temperature and pressure detection unit that detects the temperature Td of the discharge refrigerant discharged from the compressor 11.

[0082] The high-pressure side refrigerant temperature and pressure sensor 62b is a high-pressure side refrigerant temperature and pressure detection unit that detects a high-pressure side refrigerant temperature T1, which is the temperature of the refrigerant flowing out from the indoor condenser 13, and a discharge refrigerant pressure Pd, which is the pressure of the refrigerant flowing out from the indoor condenser 13. The discharge refrigerant pressure Pd in ​​this embodiment is also used as the pressure of the refrigerant discharged from the compressor 11.

[0083] The evaporator temperature sensor 62c is an evaporator temperature detection unit for detecting the refrigerant evaporation temperature (evaporator temperature) Tefin in the interior evaporator 18. Specifically, the evaporator temperature sensor 62c detects the heat exchange fin temperature of the interior evaporator 18.

[0084] The evaporator outlet side refrigerant temperature sensor 62d is an evaporator outlet side refrigerant temperature detection unit that detects the evaporator side refrigerant temperature Teout, which is the temperature of the refrigerant flowing out from the indoor evaporator .

[0085] 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, which is the temperature of the refrigerant flowing out from the refrigerant passage of the chiller 20, and the chiller side refrigerant pressure Pc, which is the pressure of the refrigerant flowing out from the refrigerant passage of the chiller 20.

[0086] The suction refrigerant temperature and pressure sensor 62f is an suction refrigerant temperature and pressure detection unit that detects the suction refrigerant temperature Ts, which is the temperature of the suction refrigerant suctioned into the compressor 11, and the suction refrigerant pressure Ps, which is the pressure of the suction refrigerant suctioned into the compressor 11.

[0087] 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 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.

[0088] The low-temperature side heat medium temperature sensor 63a is a low-temperature side heat medium temperature detection unit that detects a low-temperature side heat medium temperature TWL, which is the temperature of the low-temperature side heat medium flowing into the coolant passage a of the battery .

[0089] 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 temperatures at multiple locations of the battery 70. Therefore, the control device 60 can detect the temperature difference and temperature distribution of each battery cell that forms the battery 70. Furthermore, the average value of the detection values ​​of the multiple temperature sensors is used as the battery temperature TB.

[0090] The conditioned air temperature sensor 65 is an air conditioner temperature detection unit that detects the temperature TAV of the air blown from the mixing space 56 into the vehicle interior. The blown air temperature TAV is the object temperature of the blown air, which is the object to be heated.

[0091] Furthermore, an operation panel 69 disposed 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.

[0092] 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.

[0093] 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 blown 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 cabin.

[0094] 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 (hardware and software) that controls the operation of each control target device constitutes the control unit that controls the operation of each control target device.

[0095] For example, in the control device 60, the configuration that controls the refrigerant discharge capacity of the compressor 11 constitutes a discharge capacity control section 60a. The configuration that controls the operation of the heating section side pressure reduction section (in this embodiment, the heating expansion valve 14a and the cooling expansion valve 14c) constitutes a heating section side control section 60b. The configuration that controls the operation of the bypass side flow rate adjustment valve 14d constitutes a bypass side control section 60c. The configuration that controls the operation of the auxiliary heating section side pressure reduction section (in this embodiment, the cooling expansion valve 14b) constitutes an auxiliary heating section side control section 60d.

[0096] Next, the operation of the vehicle air conditioner 1 of this embodiment configured as described above will be described. In the vehicle air conditioner 1 of this embodiment, various operation modes are switched in order to condition the air in the vehicle cabin and adjust the temperature of the battery 70. The operation modes are switched by executing a control program stored in advance in the control device 60.

[0097] The control program is executed not only when the so-called IG switch is turned on (ON) and the vehicle system is running, but also when the battery 70 is being charged from an external power source. A main routine of the control program will be described with reference to the flowchart of Fig. 4. Each control step shown in the flowchart of Fig. 4 is a part for implementing various functions of the control device 60.

[0098] First, in step S1 in Fig. 4, initialization of flags, timers, etc., and initial position alignment of electric actuators, etc. are performed. Next, in step S2, detection signals of the control sensors and operation signals of the operation panel 69 are read. Next, in step S3, a target blown temperature TAO is determined. The target blown temperature TAO is a target value for the temperature of the blown air blown into the vehicle cabin. Therefore, step S3 is a target temperature determination section.

[0099] In step S3, the target outlet temperature TAO is determined using the following formula F1: 。 TAO=Kset×Tset-Kr×Tr-Kam×Tam-Ks×As+C…(F1) Tset is the vehicle interior target temperature 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.

[0100] Next, in step S4, an operation mode is selected based on the detection signal and operation signal read in step S2 and the target blow-out temperature TAO determined in step S3. Next, in step S5, the operation of various controlled devices is controlled so that the operation mode selected in step S4 is performed.

[0101] Next, in step S6, it is determined whether or not a predetermined termination condition for the vehicle air conditioner 1 is satisfied. If it is determined in step S6 that the termination condition is not satisfied, the process returns to step S2. This causes the control routines of reading the detection signal and the operation signal, determining the target blown temperature TAO and the operation mode, and controlling the controlled devices to be repeated. If it is determined in step S6 that the termination condition is satisfied, the program is terminated.

[0102] The termination condition in this embodiment is met when the IG switch is turned off while the battery 70 is not being charged from the external power source. Also, the termination condition is met when charging of the battery 70 from the external power source is completed while the IG switch is turned off. The detailed operation of each operation mode in step S5 will be described below.

[0103] First, a description will be given of operation modes in which the refrigerant is not circulated through the bypass passage 21c. The operation modes in which the refrigerant is not circulated through the bypass passage 21c include (a) a cooling mode, (b) a serial dehumidification heating mode, and (c) an outdoor air heat absorption heating mode.

[0104] (a) Cooling mode The cooling mode is an operation mode in which cooled air is blown into the vehicle cabin to cool the vehicle cabin. The control program selects the cooling mode when the outside air temperature Tam is relatively high (25° C. or higher in this embodiment), such as in summer.

[0105] The cooling mode includes a single cooling mode and a cool and cool mode. The single cooling mode is an operation mode in which the vehicle cabin is cooled without cooling the battery 70. The cool and cool mode is an operation mode in which the battery 70 is cooled and the vehicle cabin is cooled.

[0106] In the control program, when the battery temperature TB detected by the battery temperature sensor 64 is equal to or higher than a predetermined reference upper limit temperature KTBH, an operation mode for cooling the battery 70 is executed. This also applies to other operation modes described below.

[0107] (a-1) Single cooling mode In the heat pump cycle 10 in the cooling only mode, the control device 60 fully opens the heating expansion valve 14a, fully closes the cooling expansion valve 14b, fully closes the bypass-side flow control valve 14d, and fully closes the dehumidification opening / closing valve 22a and the heating opening / closing valve 22b.

[0108] Therefore, in the heat pump cycle 10 in the cooling only mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the following order: the indoor condenser 13, the heating expansion valve 14a which is in a fully open state, the outdoor heat exchanger 15, the cooling expansion valve 14b which is in a throttling state, the indoor evaporator 18, the accumulator 23, and the suction port of the compressor 11.

[0109] In addition, in the indoor air conditioning unit 50 in the single cooling mode, the control device 60 adjusts the opening degree of the air mix door 54 so that the blown air temperature TAV detected by the conditioned air temperature sensor 65 approaches the target blown air temperature TAO.

[0110] Furthermore, the control device 60 determines a control voltage to be output to the indoor blower 52 based on the target blowing temperature TAO by referring to a control map previously stored in the control device 60. In the control map for the cooling mode, the control voltage is determined so that the airflow rate of the indoor blower 52 is maximized 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 the airflow rate is reduced as the temperature approaches the intermediate temperature range.

[0111] Furthermore, the control device 60 controls the operation of the inside / outside air switching device 53 and the blowing mode door based on the target blowing temperature TAO by referring to a control map previously stored in the control device 60. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0112] Therefore, in the heat pump cycle 10 in the cooling only mode, the indoor condenser 13 and the outdoor heat exchanger 15 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 vapor compression refrigeration cycle.

[0113] In the interior air conditioning unit 50 in the single cooling mode, the blown air blown from the interior blower 52 is cooled by the interior evaporator 18. The blown air cooled by the interior evaporator 18 is reheated by the interior condenser 13 so as to approach the target blown air temperature TAO according to the opening degree of the air mix door 54. Then, the temperature-adjusted blown air is blown into the vehicle cabin, thereby cooling the vehicle cabin.

[0114] (a-2) Cooling mode In the heat pump cycle 10 in the cooling / air-cooling mode, the control device 60 controls the cooling expansion valve 14c to be in a throttling state in contrast to the single cooling mode.

[0115] Therefore, in the heat pump cycle 10 in the cooling / cooling mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single cooling mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the order of the indoor condenser 13, the heating expansion valve 14a in a fully open state, the outdoor heat exchanger 15, the cooling expansion valve 14c in a throttling state, the chiller 20, the accumulator 23, and the suction port of the compressor 11. In other words, the indoor evaporator 18 and the chiller 20 are switched to a refrigerant circuit in which they are connected in parallel with respect to the flow of the refrigerant.

[0116] In the low-temperature side heat medium circuit 40 in the cooling / air-cooling mode, the controller 60 operates the low-temperature side pump 41 to exert a predetermined reference pumping capacity. Therefore, in the low-temperature side heat medium circuit 40, the low-temperature side heat medium pumped by the low-temperature side pump 41 circulates through the heat medium passage of the chiller 20, the cooling water passage 70a of the battery 70, and the suction port of the low-temperature side pump 41 in that order.

[0117] In the indoor air conditioning unit 50 in the cooling / cooling mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, in the same way as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0118] Therefore, in the heat pump cycle 10 in the cooling / air-conditioning mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 and the outdoor heat exchanger 15 function as condensers, and the indoor evaporator 18 and the chiller 20 function as evaporators.

[0119] 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 and is cooled by heat exchange with the low-pressure refrigerant. The low-temperature side heat medium cooled in the chiller 20 flows through the cooling water passage 70a of the battery 70. This cools the battery 70. The low-temperature side heat medium flowing out of the cooling water passage 70a of the battery 70 is sucked into the low-temperature side pump 41 and pumped back to the chiller 20.

[0120] In the interior air conditioning unit 50 in the cooling / air-conditioning mode, temperature-adjusted air is blown into the vehicle compartment, thereby cooling the vehicle compartment, similarly to the single cooling mode.

[0121] (b) Series dehumidification and heating mode The serial dehumidifying and heating mode is an operation mode in which the cooled and dehumidified blown air is reheated and blown into the vehicle cabin to dehumidify and heat the vehicle cabin. In the control program, the serial dehumidifying and heating mode is selected when the outside air temperature Tam is within a predetermined medium-high temperature range (in this embodiment, 10°C or higher and lower than 25°C).

[0122] The series dehumidifying and heating mode includes a single series dehumidifying and heating mode and a cooling series dehumidifying and heating mode. The single series dehumidifying and heating mode is an operation mode that dehumidifies and heats the vehicle interior without cooling the battery 70. The cooling series dehumidifying and heating mode is an operation mode that cools the battery 70 and dehumidifies and heats the vehicle interior.

[0123] (b-1) Single series dehumidification and heating mode In the heat pump cycle 10 in the single series dehumidification heating mode, the control device 60 controls the heating expansion valve 14a to be throttled, the cooling expansion valve 14b to be throttled, the cooling expansion valve 14c to be fully closed, and the bypass side flow rate control valve 14d to be fully closed. The control device 60 also closes the dehumidification opening / closing valve 22a and the heating opening / closing valve 22b.

[0124] For this reason, in the heat pump cycle 10 in the single-serial dehumidification heating mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the following order: the indoor condenser 13, the heating expansion valve 14a which is in a throttling state, the outdoor heat exchanger 15, the cooling expansion valve 14b which is in a throttling state, the indoor evaporator 18, the accumulator 23, and the suction port of the compressor 11.

[0125] Furthermore, the controller 60 determines the throttle openings of the heating expansion valve 14a and the cooling expansion valve 14b based on the target blown air temperature TAO and with reference to a control map stored in advance in the controller 60.

[0126] In the control map of the series dehumidification heating mode, a control signal is determined so that the throttle opening of the heating expansion valve 14a is decreased and the throttle opening of the cooling expansion valve 14b is increased as the target blowing temperature TAO increases. Furthermore, in the control map of the series dehumidification heating mode, control signals output to the heating expansion valve 14a and the cooling expansion valve 14b are determined so that frosting of the indoor evaporator 18 can be suppressed.

[0127] In the indoor air conditioning unit 50 in the independent series dehumidifying and heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, in the same manner as in the independent cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0128] Therefore, in the heat pump cycle 10 in the single series dehumidifying and heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser and the indoor evaporator 18 functions as an evaporator.

[0129] Furthermore, in the single serial dehumidification and heating mode, when the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is higher than the outdoor air temperature Tam, the outdoor heat exchanger 15 is made to function as a condenser. When the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is lower than the outdoor air temperature Tam, the outdoor heat exchanger 15 is made to function as an evaporator.

[0130] In the indoor air conditioning unit 50 in the single serial dehumidifying and heating mode, the blown air blown from the indoor blower 52 is cooled and dehumidified in the indoor evaporator 18. The blown air cooled and dehumidified in the indoor evaporator 18 is reheated in the indoor condenser 13 so as to approach the target blown temperature TAO according to the opening degree of the air mix door 54. Then, the temperature-adjusted blown air is blown into the vehicle cabin, thereby realizing dehumidifying and heating the vehicle cabin.

[0131] (b-2) Cooling series dehumidification heating mode In the heat pump cycle 10 in the cooling series dehumidification heating mode, the controller 60 controls the cooling expansion valve 14c to the throttling state, unlike in the single series dehumidification heating mode.

[0132] Therefore, in the heat pump cycle 10 in the cooling series dehumidification heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single series dehumidification heating mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates through the indoor condenser 13, the heating expansion valve 14a in a throttling state, the outdoor heat exchanger 15, the cooling expansion valve 14c in a throttling state, the chiller 20, the accumulator 23, and the suction port of the compressor 11 in that order. In other words, the indoor evaporator 18 and the chiller 20 are switched to a refrigerant circuit in which they are connected in parallel with respect to the flow of the refrigerant.

[0133] In the low-temperature side heat medium circuit 40 in the cooling serial dehumidification heating mode, the controller 60 controls the operation of the low-temperature side pump 41 in the same manner as in the cooling / cooling mode.

[0134] In the indoor air conditioning unit 50 in the cooling serial dehumidification heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, in the same way as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0135] Therefore, in the heat pump cycle 10 in the cooling serial dehumidification heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser, and the indoor evaporator 18 and the chiller 20 function as evaporators.

[0136] Furthermore, in the cooling serial dehumidification heating mode, similarly to the single serial dehumidification heating mode, when the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is higher than the outdoor air temperature Tam, the outdoor heat exchanger 15 is made to function as a condenser. Also, when the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is lower than the outdoor air temperature Tam, the outdoor heat exchanger 15 is made to function as an evaporator.

[0137] In the low-temperature side heat medium circuit 40 in the cooling serial dehumidification heating mode, the low-temperature side heat medium cooled in the chiller 20 flows through the coolant passage 70a of the battery 70, as in the cooling air-conditioning mode, to cool the battery 70.

[0138] In the interior air conditioning unit 50 in the cooling series dehumidification heating mode, similarly to the single series dehumidification heating mode, temperature-adjusted ventilation air is blown into the vehicle compartment, thereby realizing dehumidification and heating of the vehicle compartment.

[0139] (c) Outdoor air heat absorption heating mode The outside air heat absorption heating mode is an operation mode in which heated air is blown into the vehicle cabin to heat the vehicle cabin. The control program selects the outside air heat absorption heating mode when the outside air temperature Tam is relatively low (in this embodiment, −10° C. or higher and lower than 0° C.), such as in winter.

[0140] The outside air heat absorption heating mode includes an exclusive outside air heat absorption heating mode and a cooled outside air heat absorption heating mode. The exclusive outside air heat absorption heating mode is an operation mode that heats the vehicle interior without cooling the battery 70. The cooled outside air heat absorption heating mode is an operation mode that cools the battery 70 and heats the vehicle interior.

[0141] (c-1) Single outdoor air heat absorption heating mode In the heat pump cycle 10 in the single outdoor air heat absorption heating mode, the controller 60 throttles the heating expansion valve 14a, fully closes the cooling expansion valve 14b, fully closes the cooling expansion valve 14c, and fully closes the bypass-side flow control valve 14d. The controller 60 also closes the dehumidification opening / closing valve 22a and opens the heating opening / closing valve 22b.

[0142] For this reason, in the heat pump cycle 10 in the single outdoor air heat absorption heating mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates in the following order: the indoor condenser 13, the heating expansion valve 14a which is in a throttled state, the outdoor heat exchanger 15, the heating passage 21b, the accumulator 23, and the suction port of the compressor 11.

[0143] In the indoor air conditioning unit 50 in the single outdoor air heat absorption heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, in the same way as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0144] Therefore, in the heat pump cycle 10 in the single outdoor air heat absorption heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser and the outdoor heat exchanger 15 functions as an evaporator.

[0145] In the interior air conditioning unit 50 in the single outside air heat absorption heating mode, the blown air sent from the interior blower 52 passes through the interior evaporator 18. The blown air that has passed through the interior evaporator 18 is heated by the interior condenser 13 so as to approach the target blown air temperature TAO according to the opening degree of the air mix door 54. Then, the temperature-adjusted blown air is blown into the vehicle cabin, thereby heating the vehicle cabin.

[0146] (c-2) Cooling outdoor air heat absorption heating mode In the heat pump cycle 10 in the cooling outdoor air heat absorption heating mode, the controller 60 throttles the cooling expansion valve 14c in comparison with the single outdoor air heat absorption heating mode. Also, the controller 60 opens the dehumidification opening / closing valve 22a.

[0147] Therefore, in the heat pump cycle 10 in the cooling outdoor air heat absorption heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single outdoor air heat absorption heating mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the order of the indoor condenser 13, the dehumidification passage 21a, the cooling expansion valve 14c in the throttling state, the chiller 20, the accumulator 23, and the suction port of the compressor 11. In other words, the outdoor heat exchanger 15 and the chiller 20 are switched to a refrigerant circuit in which they are connected in parallel with respect to the flow of the refrigerant.

[0148] In the low-temperature side heat medium circuit 40 in the cooled outdoor air heat absorption heating mode, the controller 60 controls the operation of the low-temperature side pump 41 in the same manner as in the cooling / cooling mode.

[0149] In the indoor air conditioning unit 50 in the cooling outdoor air heat absorption heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, in the same way as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0150] Therefore, in the heat pump cycle 10 in the cooled outdoor air heat absorption heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser and the outdoor heat exchanger 15 and the chiller 20 function as evaporators.

[0151] In the low-temperature side heat medium circuit 40 in the cooling outside air heat absorption heating mode, the low-temperature side heat medium cooled in the chiller 20 flows through the coolant passage 70a of the battery 70, thereby cooling the battery 70, as in the cooling / cooling mode.

[0152] In the interior air-conditioning unit 50 in the cooled outside air heat absorption heating mode, the temperature-adjusted blown air is blown into the vehicle compartment, as in the single outside air heat absorption heating mode, thereby heating the vehicle compartment.

[0153] Next, the operation modes in which the refrigerant flows through the bypass passage 21c will be described. The operation modes in which the refrigerant flows through the bypass passage 21c include (d) a hot gas heating mode, (e) a hot gas dehumidification heating mode, and (f) a hot gas serial dehumidification heating mode.

[0154] (d) Hot gas heating mode The hot gas heating mode is an operation mode for heating the vehicle interior. In the control program, the hot gas heating mode is selected when the outside air temperature Tam is extremely low (in this embodiment, less than -10°C) or when it is determined that the heating capacity of the interior condenser 13 for heating the blown air is insufficient during the outside air heat absorption heating mode.

[0155] In the control program, when the blown air temperature TAV is lower than the target outlet temperature TAO, it is determined that the heating capacity of the blown air is insufficient. This also applies to the other operating modes.

[0156] The hot gas heating mode includes a single hot gas heating mode and a cooled hot gas heating mode.

[0157] The sole hot gas heating mode is an operation mode in which the interior of the vehicle is heated without adjusting the temperature of the battery 70. The cooled hot gas heating mode is an operation mode in which the battery 70 is cooled while the hot gas heating mode is being executed.

[0158] In the control program, when the hot gas heating mode is being executed, the cooling hot gas heating mode is selected when the battery temperature TB is equal to or higher than the reference upper limit temperature KTBH and the chiller side refrigerant temperature Tc detected by the chiller side refrigerant temperature and pressure sensor 62e is lower than the low-temperature side heat medium temperature TWL detected by the low-temperature side heat medium temperature sensor 63a.

[0159] (d-1) Single hot gas heating mode In the heat pump cycle 10 in the single hot gas heating mode, the controller 60 fully closes the heating expansion valve 14a, fully closes the cooling expansion valve 14b, throttles the cooling expansion valve 14c, and throttles the bypass-side flow control valve 14d. The controller 60 also opens the dehumidification on-off valve 22a and closes the heating on-off valve 22b.

[0160] Therefore, in the heat pump cycle 10 in the single hot gas heating mode, as shown by the solid line arrow in Fig. 5, the refrigerant discharged from the compressor 11 circulates in the order of the first three-way joint 12a, the indoor condenser 13, the dehumidification passage 21a, the four-way joint 12x, the cooling expansion valve 14c in the throttled state, the chiller 20, the sixth three-way joint 12f, the accumulator 23, and the suction port 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 the order of the first three-way joint 12a, the bypass side flow control valve 14d in the throttled state arranged in the bypass passage 21c, the sixth three-way joint 12f, the accumulator 23, and the suction port of the compressor 11.

[0161] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the suction refrigerant pressure Ps detected by the suction refrigerant temperature and pressure sensor 62f approaches a predetermined first target low pressure PSO1.

[0162] Here, controlling the suction refrigerant pressure Ps to approach a constant value is effective for stabilizing the discharge flow rate Gr (mass flow rate) of the compressor 11. More specifically, by making the suction refrigerant pressure Ps a saturated gas-phase refrigerant with a constant pressure, the density of the suction refrigerant becomes constant. Therefore, controlling the suction refrigerant pressure Ps to approach a constant pressure makes it easier to stabilize the discharge flow rate Gr of the compressor 11 at the same rotation speed.

[0163] Furthermore, the control device 60 changes the throttle opening of the bypass side flow rate adjustment valve 14d so that the discharge refrigerant pressure Pd detected by the high pressure side refrigerant temperature and pressure sensor 62b approaches the target high pressure PDO.

[0164] The target high pressure PDO is determined based on the target blowing temperature TAO by referring to a control map stored in advance in the control device 60. In the control map for the hot gas heating mode, the target high pressure PDO is determined so as to increase with an increase in the target blowing temperature TAO. Furthermore, in the control map for the hot gas heating mode, the target high pressure PDO is determined so that the blowing air temperature TAV can be brought close to the target blowing temperature TAO.

[0165] In addition, the control device 60 changes the throttle opening of the cooling expansion valve 14c so that the degree of subcooling SC1 of the refrigerant flowing out from the indoor condenser 13 approaches a first target degree of subcooling SCO1. The degree of subcooling SC1 can be obtained using the high-pressure side refrigerant temperature T1 detected by the high-pressure side refrigerant temperature / pressure sensor 62b and the discharge refrigerant pressure Pd.

[0166] The first target subcooling degree SCO1 is determined by referring to a control map previously stored in the control device 60. In the control map for the hot gas heating mode, the first target subcooling degree SCO1 is determined so that the dryness Rx of the suction refrigerant approaches a predetermined reference dryness KRx. The reference dryness KRx is set to a relatively high value close to that of a saturated gas-phase refrigerant.

[0167] Furthermore, upper limit opening control is executed in the heat pump cycle 10 in the hot gas heating mode. The upper limit opening control is a control for controlling the throttle opening of the other of the heating section side pressure reduction section and the bypass side flow control valve 14d to the upper limit opening or less when the flow rate adjustment capacity of either the heating section side pressure reduction section or the bypass side flow control valve 14d is equal to or less than a predetermined reference adjustment capacity. In other words, the upper limit opening control is a control that reduces the throttle opening of the other of the heating unit side pressure reduction section and the bypass side flow control valve 14d when the flow control capacity of either the heating unit side pressure reduction section or the bypass side flow control valve 14d is below a predetermined standard control capacity.

[0168] The upper limit opening control will be described with reference to the flowchart in Fig. 6. The flowchart in Fig. 6 shows a control process executed as a subroutine in step S5 when (d) hot gas heating mode, (e) hot gas dehumidification heating mode, or (f) hot gas serial dehumidification heating mode is selected in step S4 of the main routine of the control program.

[0169] First, in step S11 of Fig. 6, a control zone for controlling the upper limit opening is determined. Specifically, in step S11, the one with the larger throttle opening of the heating section side pressure reducing section and the bypass side flow rate adjustment valve 14d is defined as one variable throttle mechanism, and the one with the smaller throttle opening is defined as the other variable throttle mechanism. Then, based on the throttle opening of one variable throttle mechanism, a control zone for determining the upper limit opening is determined as shown in the control characteristic diagram in step S11 of Fig. 6.

[0170] In the control characteristics diagram of this embodiment, when the aperture opening of one variable throttle mechanism is less than the reference limit opening (90% in this embodiment), the control zone is determined to be zone 0. Then, when the aperture opening of one variable throttle mechanism is equal to or greater than the reference limit opening, the control zones are determined in the order of zone 1, zone 2, and zone 3 as the aperture opening of the one variable throttle mechanism increases.

[0171] Here, the throttle opening of the heating section-side pressure reducing section in the hot gas heating mode is the throttle opening of the cooling side expansion valve 14c.

[0172] The throttle opening of the variable throttle mechanism can be defined as the ratio of the current throttle passage area to the throttle passage area in the fully open state. The throttle passage area in the fully open state is determined by the product specifications. In a variable throttle mechanism having a stepping motor as a drive unit for displacing the valve body, the current throttle opening can be estimated using the control pulses sent from the control device 60.

[0173] Next, in step S12, it is determined whether the control zone determined in step S11 is zone 0. If it is determined in step S12 that the control zone is zone 0, the process returns to the main routine. Therefore, if it is determined in step S12 that the control zone is zone 0, the upper limit opening is not set. If it is determined in step S12 that the control zone is not zone 0, the process proceeds to step S13.

[0174] In step S13, the upper limit of the throttle opening of the other variable throttle mechanism is determined for each control zone, and the process returns to the main routine. In other words, in step S13, the amount of reduction in the aperture opening of the other variable aperture mechanism is determined for each control zone, and the process returns to the main routine. Therefore, step S13 is an upper limit opening determination section. Specifically, in step S13, as shown in the control characteristic diagram in step S13 of FIG. 6, the upper limit opening is determined using the change rate determined for each control zone.

[0175] The rate of change ZA1 in the control characteristic diagram shown in step S13 is a value equal to or less than 1. The rate of change ZA2 is a value smaller than the rate of change ZA1. The rate of change ZA3 is a value smaller than the rate of change ZA2.

[0176] In zone 1, the upper limit opening is determined to be ZA1 times the aperture opening of the other variable throttle mechanism in the previous control routine. Therefore, when the control zone is zone 1, increasing the aperture opening of the other variable throttle mechanism in the current control routine is prohibited. Furthermore, if ZA1 is a value smaller than 1, the aperture opening of the other variable throttle mechanism may be decreased in the current control routine.

[0177] In zone 2, the upper limit opening is determined to be ZA2 times the aperture opening of the other variable aperture mechanism in the previous control routine. Therefore, when the control zone is zone 2, the aperture opening of the other variable aperture mechanism may be reduced in the current control routine. Furthermore, when the control zone is zone 2, the amount of reduction in the aperture opening of the other variable aperture mechanism can be increased compared to when the control zone is zone 1.

[0178] In zone 3, the upper limit opening is determined to be ZA3 times the aperture opening of the other variable throttle mechanism in the previous control routine. Therefore, when the control zone is zone 2, the aperture opening of the other variable throttle mechanism may be reduced in the current control routine. Furthermore, when the control zone is zone 3, the amount of reduction in the aperture opening of the other variable throttle mechanism can be increased compared to when the control zone is zone 2.

[0179] Here, in the variable throttling mechanism such as the cooling expansion valve 14c and the bypass side flow rate control valve 14d, the flow rate control capability decreases as the throttling opening increases. This is because as the throttling opening increases, the differential pressure across the variable throttling mechanism, calculated by subtracting the refrigerant pressure across the downstream side from the refrigerant pressure across the upstream side, decreases, and the amount of change in flow rate decreases. In other words, the differential pressure across the variable throttling mechanism corresponds to the amount of pressure reduction of the refrigerant in the variable throttling mechanism.

[0180] Therefore, in the upper limit opening control of this embodiment, when the throttle opening of one of the variable throttle mechanisms is equal to or greater than the reference limit opening, it is determined that the flow rate adjustment capacity of the one of the variable throttle mechanisms is equal to or less than the reference adjustment capacity. Therefore, step S12 is an adjustment capacity determination section. Furthermore, in step S13, which is an upper limit opening determination section of this embodiment, the upper limit opening is determined to be a low value as the throttle opening of the one of the variable throttle mechanisms increases. In other words, in step S13 which is the upper limit opening determination section of this embodiment, as the aperture opening of one variable aperture mechanism increases, the amount by which the aperture opening of the other variable aperture mechanism is decreased is increased.

[0181] Furthermore, in the low-temperature side heat medium circuit 40 in the single hot gas heating mode, the control device 60 stops the low-temperature side pump 41.

[0182] In the indoor air conditioning unit 50 in the sole hot gas heating mode, the control device 60 controls the opening degree of the air mix door 54 in the same manner as in the sole cooling mode. In the hot gas heating mode, the control device 60 often controls the opening degree of the air mix door 54 so that almost the entire amount of the air blown from the indoor blower 52 passes through the indoor condenser 13.

[0183] The control device 60 also controls the operation of the inside / outside air switching device 53 so as to introduce inside air into the air conditioning case 51. The control device 60 also controls the blowing capacity of the indoor blower 52 and the operation of the blowing mode door, as in the single cooling mode. The control device 60 also appropriately controls the operation of other devices to be controlled.

[0184] Therefore, in the heat pump cycle 10 in the sole hot gas heating mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0185] First, the flow of the discharged refrigerant (point a7 in FIG. 7) discharged from 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 indoor condenser 13 and dissipates heat to the blown air (from point a7 to point b7 in FIG. 7). This heats the blown air.

[0186] The refrigerant flowing out from the indoor condenser 13 flows into the dehumidification passage 21a. The refrigerant flowing into the dehumidification passage 21a flows into the cooling expansion valve 14c and is reduced in pressure (from point b7 to point c7 in FIG. 7).

[0187] The refrigerant decompressed by the cooling expansion valve 14c flows into the chiller 20. In the hot gas heating mode, the low-temperature side pump 41 is stopped, so there is no heat exchange between the refrigerant and the low-temperature side heat medium in the chiller 20. The refrigerant that flows out of the chiller 20 flows into the other inlet of the sixth three-way joint 12f.

[0188] The other refrigerant branched at the first three-way joint 12a flows into the bypass passage 21c. The refrigerant that flows into the bypass passage 21c is flow-regulated and depressurized by the bypass-side flow rate adjustment valve 14d (from point a7 to point d7 in FIG. 7). The refrigerant depressurized by the bypass-side flow rate adjustment valve 14d flows into one inlet of the sixth three-way joint 12f.

[0189] The refrigerant flowing out from the chiller 20 and the refrigerant flowing out from the bypass-side flow control valve 14d join and are mixed at the sixth three-way joint 12f. The refrigerant flowing out from the sixth three-way joint 12f flows into the accumulator 23 via the fifth three-way joint 12e and the fourth three-way joint 12d.

[0190] The refrigerant that flows into the accumulator 23 is mixed more homogeneously (point e7 in FIG. 7). As a result, the quality factor Rx of the suctioned refrigerant approaches the reference quality factor KRx. The refrigerant that flows out of the accumulator 23 is sucked into the compressor 11 and compressed again.

[0191] As described above, in the heat pump cycle 10 in hot gas heating mode, refrigerants with different enthalpies, such as a refrigerant with low enthalpy flowing out from the chiller 20 (point c7 in Figure 7) and a refrigerant with high enthalpy flowing out from the bypass passage 21c (point d7 in Figure 7), are mixed and sucked into the compressor 11.

[0192] Therefore, in the heat pump cycle 10 in the hot gas heating mode, the cooling expansion valve 14c serves as a heating section side pressure reducing section, and the sixth three-way joint 12f serves as a mixing section.

[0193] In the heat pump cycle 10 in the hot gas heating mode, adjusting the throttle opening of the cooling expansion valve 14c so that the subcooling degree SC1 approaches the first target subcooling degree SCO1 means controlling the cycle balance.

[0194] That is, in the hot gas heating mode, the throttle opening of the cooling expansion valve 14c is adjusted so that the subcooling degree SC1 approaches the first target subcooling degree SCO1, thereby making the dryness Rx of the suction refrigerant approach the reference dryness KRx. In other words, the state of the suction refrigerant is made to approach a gas-liquid two-phase refrigerant that contains an appropriate amount of liquid-phase refrigerant with refrigeration oil dissolved therein.

[0195] Furthermore, in the hot gas heating mode, the refrigerant discharge capacity of the compressor 11 is controlled so that the suction refrigerant pressure Ps approaches the first target low pressure PSO1. The amount of work of the compressor 11 is determined by the refrigerant discharge capacity of the compressor 11. The discharge refrigerant pressure Pd is balanced to a pressure at which the heat generated by the work of the compressor 11 can be dissipated in the indoor condenser 13.

[0196] That is, in the heat pump cycle 10 in the hot gas heating mode, the suction refrigerant pressure Ps is controlled by adjusting the refrigerant discharge capacity of the compressor 11. Furthermore, the discharge refrigerant pressure Pd is controlled by adjusting the throttle opening of the cooling expansion valve 14c and the bypass side flow rate control valve 14d.

[0197] Therefore, in the hot gas heating mode, the operation of at least one of the compressor 11, the cooling expansion valve 14c, and the bypass side flow control valve 14d is controlled so that the blowing air temperature TAV approaches the target blowing temperature TAO and the dryness Rx of the suction refrigerant approaches the reference dryness KRx.

[0198] In the interior air conditioning unit 50 in the single hot gas heating mode, the blown air that has passed through the interior evaporator 18 is heated by the interior condenser 13 and blown out into the vehicle cabin. This realizes heating of the vehicle cabin.

[0199] Here, the single hot gas heating mode is an operation mode that is executed when the outdoor air temperature Tam is extremely low. Therefore, when the refrigerant that flows out of the indoor condenser 13 flows into the outdoor heat exchanger 15, the refrigerant may dissipate heat to the outdoor air in the outdoor heat exchanger 15. If the refrigerant dissipates heat to the outdoor air in the outdoor heat exchanger 15, the amount of heat that the refrigerant dissipates to the blown air in the indoor condenser 13 decreases, and the heating capacity of the blown air decreases.

[0200] In contrast, in the single hot gas heating mode of this embodiment, the refrigerant circuit is switched to one that does not allow the refrigerant flowing out of the indoor condenser 13 to flow into the outdoor heat exchanger 15, thereby preventing the refrigerant from releasing heat to the outside air in the outdoor heat exchanger 15.

[0201] Furthermore, the throttle opening of the cooling expansion valve 14c is changed so that the degree of subcooling SC1 of the refrigerant flowing out from the indoor condenser 13 approaches the first target degree of subcooling SCO1. This makes it possible to bring the state of the suctioned refrigerant closer to an appropriate state even if the refrigerant discharge capacity of the compressor 11 is increased to increase the amount of heat dissipated from the discharged refrigerant to the blown air in the indoor condenser 13.

[0202] Therefore, in the single hot gas heating mode, even if the outside air temperature Tam is extremely low, the heat generated by the work of the compressor 11 can be effectively used to heat the blown air, thereby realizing heating of the passenger compartment.

[0203] (d-2) Cooling hot gas heating mode In the cooling hot gas heating mode, unlike the single hot gas heating mode, the control device 60 operates the low-temperature side pump 41 of the low-temperature side heat medium circuit 40 so as to exert a predetermined reference pumping capacity. Therefore, in the heat pump cycle 10 in the cooling hot gas heating mode, the refrigerant that has flowed into the chiller 20 absorbs heat from the low-temperature side heat medium. This causes the low-temperature side heat medium to be cooled. Other operations are the same as in the single hot gas heating mode.

[0204] Therefore, in the cooling hot gas heating mode, similarly to the single hot gas heating mode, the heat generated by the work of the compressor 11 is effectively used to heat the blown air, thereby realizing heating of the vehicle cabin. Furthermore, in the low-temperature side heat medium circuit 40 in the cooling hot gas heating mode, the low-temperature side heat medium cooled by the chiller 20 flows through the coolant passage 70a of the battery 70. This allows the battery 70 to be cooled.

[0205] (e) Hot gas dehumidification heating mode The hot gas dehumidifying and heating mode is an operation mode for dehumidifying and heating the vehicle interior. In the control program, the hot gas dehumidifying and heating mode is selected when the outside air temperature Tam is in a predetermined low-medium temperature range (in this embodiment, 0°C or higher and lower than 10°C).

[0206] The hot gas dehumidifying heating mode includes a standalone hot gas dehumidifying heating mode and a cooled hot gas dehumidifying heating mode. The standalone hot gas dehumidifying heating mode is an operation mode that dehumidifies and heats the vehicle interior without cooling the battery 70. The cooled hot gas dehumidifying heating mode is an operation mode that cools the battery 70 and dehumidifies and heats the vehicle interior.

[0207] (e-1) Single hot gas dehumidification heating mode In the heat pump cycle 10 in the single hot gas dehumidification heating mode, the control device 60 fully closes the heating expansion valve 14a, throttles the cooling expansion valve 14b, throttles the cooling expansion valve 14c, and throttles the bypass side flow control valve 14d. The control device 60 also opens the dehumidification opening / closing valve 22a and closes the heating opening / closing valve 22b.

[0208] Therefore, in the heat pump cycle 10 in the single hot gas dehumidification heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single hot gas heating mode, as shown by the solid arrows in Fig. 8. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates in the order of the first three-way joint 12a, the indoor condenser 13, the dehumidification passage 21a, the four-way joint 12x, the cooling expansion valve 14b in the throttled state, the indoor evaporator 18, the accumulator 23, and the suction port of the compressor 11. In other words, the indoor evaporator 18 and the chiller 20 are switched to a refrigerant circuit in which the refrigerant flows in parallel.

[0209] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the suction refrigerant pressure Ps approaches a predetermined second target low pressure PSO2. The second target low pressure PSO2 is determined so that the refrigerant evaporation temperature in the indoor evaporator 18 is a temperature at which the blown air can be dehumidified without causing frost on the indoor evaporator 18.

[0210] Furthermore, similarly to the hot gas heating mode, the controller 60 changes the throttle opening of the bypass side flow rate control valve 14d so that the discharge refrigerant pressure Pd approaches the target high pressure PDO.

[0211] In addition, the control device 60 changes the throttle opening of the cooling expansion valve 14b so that the degree of subcooling SC1 of the refrigerant flowing out from the indoor condenser 13 approaches a second target degree of subcooling SCO2. The second target degree of subcooling SCO2 is determined by referring to a control map stored in advance in the control device 60.

[0212] The control device 60 also changes the throttle opening of the cooling expansion valve 14c so that the dryness Rx of the suction refrigerant approaches the reference dryness KRx. The dryness Rx of the suction refrigerant can be estimated using the evaporator temperature Tefin detected by the evaporator temperature sensor 62c, the evaporator side refrigerant temperature Teout detected by the evaporator outlet side refrigerant temperature sensor 62d, the suction refrigerant temperature Ts, the suction refrigerant pressure Ps, and the like.

[0213] Furthermore, in the heat pump cycle 10 in the hot gas dehumidification heating mode, the upper limit opening control is executed as in the hot gas heating mode. The opening of the heating section side pressure reducing section in the hot gas dehumidification heating mode is the opening of the cooling side expansion valve 14c.

[0214] In addition, in the heat pump cycle 10 in the hot gas dehumidification heating mode, an opening increase control is executed. The opening increase control is a control for increasing the opening of the cooling expansion valve 14b when the throttle opening of the cooling expansion valve 14c is equal to or greater than a predetermined reference increased opening (in this embodiment, 90% of full opening) and the superheat degree SH is equal to or greater than the upper limit superheat degree KSHM (in this embodiment, 15°C).

[0215] The opening degree increasing control will be described with reference to the flowchart in Fig. 9. The flowchart in Fig. 9 shows a control process executed as a subroutine in step S5 when (e) the hot gas dehumidifying heating mode and (f) the hot gas in-line dehumidifying heating mode are selected in step S4 of the main routine of the control program.

[0216] First, in step S21 of FIG. 9, a control zone for the opening degree increasing control is determined as shown in the control characteristic diagram depicted in step S21 of FIG.

[0217] Specifically, in the control characteristic diagram of this embodiment, when the throttle opening of the cooling expansion valve 14c is less than a reference increased opening (90% in this embodiment), the control zone is determined to be zone 0. Then, when the throttle opening of the cooling expansion valve 14c is equal to or greater than the reference increased opening and the superheat degree SH is equal to or greater than the upper limit superheat degree KSHM, the control zones are determined in the order of zone 1, zone 2, and zone 3 as the throttle opening of the cooling expansion valve 14c increases.

[0218] Next, in step S22, it is determined whether the control zone determined in step S21 is zone 0. If it is determined in step S22 that the control zone is zone 0, the process returns to the main routine. Therefore, if it is determined in step S22 that the control zone is zone 0, the throttle opening of the heating unit side pressure reducing unit is not increased. If it is determined in step S22 that the control zone is not zone 0, the process proceeds to step S23.

[0219] In step S23, as shown in the control characteristics diagram depicted in step S23 of FIG. 9, the rate of change determined for each control zone is used to determine the throttle opening of the cooling expansion valve 14b in the current control routine.

[0220] The rate of change ZB1 in the control characteristic diagram shown in step S23 is a value equal to or greater than 1. The rate of change ZB2 is a value greater than the rate of change ZB1. The rate of change ZB3 is a value greater than the rate of change ZB2.

[0221] In zone 1, the throttle opening of the cooling expansion valve 14b is determined to be ZB1 times the throttle opening of the cooling expansion valve 14b in the previous control routine. Therefore, when the control zone is zone 1, the throttle opening of the cooling expansion valve 14b is prohibited from being decreased in the current control routine. Furthermore, if ZB1 is a value greater than 1, the throttle opening of the cooling expansion valve 14b is increased in the current control routine.

[0222] In zone 2, the throttle opening of the cooling expansion valve 14b is determined to be ZB2 times the throttle opening of the cooling expansion valve 14b in the previous control routine. Therefore, when the control zone is zone 2, the throttle opening of the cooling expansion valve 14b is increased in the current control routine. Furthermore, when the control zone is zone 2, the increase in the throttle opening of the cooling expansion valve 14b can be made larger than when the control zone is zone 1.

[0223] In zone 3, the throttle opening of the cooling expansion valve 14b is determined to be ZB3 times the throttle opening of the cooling expansion valve 14b in the previous control routine. Therefore, when the control zone is zone 3, the throttle opening of the cooling expansion valve 14b is increased in the current control routine. Furthermore, when the control zone is zone 3, the increase in the throttle opening of the cooling expansion valve 14b can be made larger than when the control zone is zone 2.

[0224] Therefore, in the opening increase control, when the throttle opening of the cooling expansion valve 14c is equal to or greater than the reference increased opening and the superheat degree SH is equal to or greater than the upper limit superheat degree KSHM, the throttle opening of the cooling expansion valve 14b is prohibited from being reduced.

[0225] In addition, in the low-temperature side heat medium circuit 40 in the single hot gas dehumidification heating mode, the control device 60 stops the low-temperature side pump 41.

[0226] In the indoor air conditioning unit 50 in the single hot gas dehumidifying heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, in the same way as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0227] Therefore, in the heat pump cycle 10 in the single hot gas dehumidification heating mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0228] The flow of the discharged refrigerant (point a10 in FIG. 10) discharged from 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 indoor condenser 13 and dissipates heat to the blown air (from point a10 to point b10 in FIG. 10). As a result, the blown air that has been cooled and dehumidified in the indoor evaporator 18 is reheated.

[0229] The refrigerant flowing out from the indoor condenser 13 flows into the dehumidification passage 21a. The flow of the refrigerant flowing into the dehumidification passage 21a is branched at the four-way joint 12x. One of the refrigerant branches at the four-way joint 12x flows into the cooling expansion valve 14b and is decompressed (from point b10 to point f10 in FIG. 10).

[0230] The refrigerant decompressed by the cooling expansion valve 14b flows into the indoor evaporator 18. The refrigerant that flows into the indoor evaporator 18 evaporates through heat exchange with the blown air blown from the indoor blower 52. This cools and dehumidifies the blown air. The refrigerant that flows out of the indoor evaporator 18 flows into one inlet of the fifth three-way joint 12e via the second check valve 16b.

[0231] The other refrigerant branched at the four-way joint 12x flows into the cooling expansion valve 14c and is decompressed (from point b10 to point c10 in FIG. 10). The refrigerant decompressed at the cooling expansion valve 14c flows into the other inlet of the sixth three-way joint 12f, as in the hot gas heating mode.

[0232] The other refrigerant branched at the first three-way joint 12a flows into the bypass passage 21c. The refrigerant that flows into the bypass passage 21c is flow-regulated and decompressed by the bypass-side flow control valve 14d (from point a10 to point d10 in FIG. 10) in the same manner as in the hot gas heating mode, and flows into one inlet of the sixth three-way joint 12f.

[0233] The refrigerant flowing out from the chiller 20 and the refrigerant flowing out from the bypass side flow control valve 14d join and are mixed at the sixth three-way joint 12f. The refrigerant flowing out from the sixth three-way joint 12f and the refrigerant flowing out from the indoor evaporator 18 join and are mixed at the fifth three-way joint 12e. The refrigerant flowing out from the fifth three-way joint 12e flows into the accumulator 23 via the fourth three-way joint 12d.

[0234] The refrigerant that flows into the accumulator 23 is mixed more homogeneously (point e10 in FIG. 10). As a result, the quality of the suctioned refrigerant Rx approaches the reference quality of the refrigerant KRx. The refrigerant that flows out of the accumulator 23 is sucked into the compressor 11 and compressed again.

[0235] Here, in Fig. 10, the pressure of the refrigerant decompressed by the cooling expansion valve 14c (point c10 in Fig. 10) is shown as a value lower than the pressure of the refrigerant decompressed by the cooling expansion valve 14b (point f10 in Fig. 10), but is not limited to this. The pressure of the refrigerant decompressed by the cooling expansion valve 14c may be higher than or equal to the pressure of the refrigerant decompressed by the cooling expansion valve 14b.

[0236] As described above, the heat pump cycle 10 in the hot gas dehumidification heating mode is switched to a refrigerant circuit in which refrigerants with different enthalpies, such as the refrigerant with low enthalpy flowing out from the chiller 20 (point c12 in Figure 10), the refrigerant with high enthalpy flowing out from the bypass passage 21c (point d12 in Figure 10), and the refrigerant flowing out from the indoor evaporator 18, are mixed and sucked into the compressor 11.

[0237] Therefore, in the heat pump cycle 10 in the hot gas dehumidifying and heating mode, the cooling expansion valve 14c serves as a heating section side pressure reducing section, the sixth three-way joint 12f serves as a mixing section, the four-way joint 12x serves as an auxiliary branch section, the cooling expansion valve 14b serves as an auxiliary heating section side pressure reducing section, and the indoor evaporator 18 serves as an evaporation section.

[0238] In the heat pump cycle 10 in the hot gas dehumidification heating mode, the cycle balance is controlled by adjusting the throttle opening of the cooling expansion valve 14b so that the subcooling degree SC1 approaches the second target subcooling degree SCO2. Also, the throttle opening of the cooling expansion valve 14c is adjusted so that the dryness Rx approaches the reference dryness KRx, thereby making the state of the suction refrigerant closer to a gas-liquid two-phase refrigerant that contains an appropriate amount of liquid-phase refrigerant with refrigeration oil dissolved therein.

[0239] Furthermore, in the hot gas dehumidifying heating mode, the refrigerant discharge capacity of the compressor 11 is controlled so that the suction refrigerant pressure Ps approaches the second target low pressure PSO2. At this time, the refrigerant discharge capacity of the compressor 11 is a refrigerant discharge capacity capable of passing the total flow rate (mass flow rate) of the refrigerant flowing out from the indoor evaporator 18, the refrigerant flowing out from the chiller 20, and the refrigerant flowing through the bypass passage 21c.

[0240] The amount of work done by the compressor 11 is determined by the refrigerant discharge capacity of the compressor 11. The discharge refrigerant pressure Pd is set to a pressure that balances the heat absorbed by the refrigerant in the indoor evaporator 18 and the heat generated by the work done by the compressor 11 at a pressure that allows the indoor condenser 13 to dissipate both heat.

[0241] That is, in the heat pump cycle 10 in the hot gas dehumidification heating mode, the suction refrigerant pressure Ps is controlled by adjusting the refrigerant discharge capacity of the compressor 11. Furthermore, the discharge refrigerant pressure Pd is controlled by adjusting the throttle opening of the cooling expansion valve 14c and the bypass side flow control valve 14d.

[0242] Therefore, in the hot gas dehumidification heating mode, the operation of at least one of the compressor 11, the cooling expansion valve 14c, and the bypass side flow control valve 14d is controlled so that the blowing air temperature TAV approaches the target blowing temperature TAO and the dryness Rx of the suction refrigerant approaches the reference dryness KRx.

[0243] In the indoor air conditioning unit 50 in the single hot gas dehumidifying and heating mode, the blown air cooled and dehumidified in the indoor evaporator 18 is reheated in the indoor condenser 13 and blown into the vehicle cabin. This realizes dehumidifying and heating the vehicle cabin.

[0244] Here, the single hot gas dehumidifying and heating mode is an operation mode in which the blown air is cooled and dehumidified, and the dehumidified blown air is reheated to a desired temperature and blown into the vehicle interior. Therefore, in the single hot gas dehumidifying and heating mode, the workload of the compressor 11 must be adjusted so that the blown air can be reheated to the desired temperature in the heating section without causing frost on the interior evaporator 18.

[0245] In contrast, in the single hot gas dehumidifying and heating mode of this embodiment, a refrigerant with a relatively high enthalpy is caused to flow into the mixing section through the bypass passage 21c. This makes it possible to suppress a decrease in the pressure of the suction refrigerant even if the refrigerant discharge capacity of the compressor 11 is increased. As a result, it is possible to increase the amount of heat dissipated from the discharged refrigerant to the blown air in the indoor condenser 13 without causing frost formation on the indoor evaporator 18.

[0246] Therefore, in the single hot gas dehumidification and heating mode, the blown air can be heated with a higher heating capacity than in the series dehumidification and heating mode.

[0247] (e-2) Cooling hot gas dehumidification heating mode In the cooling hot gas dehumidifying heating mode, the control device 60 operates the low-temperature side pump 41 to achieve a predetermined standard pumping capacity in comparison with the single hot gas dehumidifying heating mode. Therefore, in the heat pump cycle 10 in the cooling hot gas dehumidifying heating mode, the refrigerant that has flowed into the chiller 20 absorbs heat from the low-temperature side heat medium. This causes the low-temperature side heat medium to be cooled. Other operations are the same as those in the single hot gas dehumidifying heating mode.

[0248] Therefore, in the cooling hot gas dehumidifying heating mode, like the single hot gas dehumidifying heating mode, the blown air is heated with a heating capacity higher than that of the series dehumidifying heating mode, and dehumidifying and heating the vehicle interior can be realized. Furthermore, in the low-temperature side heat medium circuit 40 in the cooling hot gas dehumidifying heating mode, the low-temperature side heat medium cooled by the chiller 20 flows through the coolant passage 70a of the battery 70. This allows the battery 70 to be cooled.

[0249] (f) Hot gas serial dehumidification heating mode The hot gas series dehumidification heating mode is an operation mode for dehumidifying and heating the vehicle interior. In the control program, when the vehicle interior condenser 13 is judged to have insufficient heating capacity for the ventilation air during the series dehumidification heating mode, the hot gas series dehumidification heating mode is selected.

[0250] The hot gas series dehumidifying and heating mode includes a single hot gas series dehumidifying and heating mode and a cooled hot gas series dehumidifying and heating mode. The single hot gas series dehumidifying and heating mode is an operation mode that dehumidifies and heats the vehicle interior without cooling the battery 70. The cooled hot gas series dehumidifying and heating mode is an operation mode that cools the battery 70 and dehumidifies and heats the vehicle interior.

[0251] (f-1) Single hot gas series dehumidification heating mode In the heat pump cycle 10 in the single hot gas series dehumidification heating mode, the control device 60 throttles the heating expansion valve 14a, throttles the cooling expansion valve 14b, throttles the cooling expansion valve 14c, and throttles the bypass side flow control valve 14d. The control device 60 also closes the dehumidification on-off valve 22a and closes the heating on-off valve 22b.

[0252] Therefore, in the heat pump cycle 10 in the single hot gas series dehumidification heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the cooling series dehumidification heating mode, as shown by the solid arrows in Fig. 11. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates through the first three-way joint 12a, the bypass-side flow control valve 14d in the throttling state arranged in the bypass passage 21c, the sixth three-way joint 12f, the accumulator 23, and the suction port of the compressor 11 in that order.

[0253] Furthermore, similarly to the hot gas dehumidification heating mode, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the suction refrigerant pressure Ps approaches a predetermined second target low pressure PSO2.

[0254] Furthermore, similarly to the hot gas heating mode, the controller 60 changes the throttle opening of the bypass side flow rate control valve 14d so that the discharge refrigerant pressure Pd approaches the target high pressure PDO.

[0255] Furthermore, the control device 60 changes the throttle openings of the heating expansion valve 14a and the cooling expansion valve 14b in the same manner as in the series dehumidification heating mode.

[0256] Furthermore, similarly to the hot gas dehumidification heating mode, the control device 60 changes the throttle opening of the cooling expansion valve 14c so that the dryness Rx of the suction refrigerant approaches the reference dryness KRx.

[0257] Furthermore, in the heat pump cycle 10 in the hot gas in-line dehumidifying and heating mode, the upper limit opening control is executed as in the hot gas heating mode. The opening of the heating section side pressure reducing section in the hot gas in-line dehumidifying and heating mode is the total opening calculated from the combined value of the passage resistance in the heating expansion valve 14a and the passage resistance in the cooling expansion valve 14c.

[0258] In addition, in the heat pump cycle 10 in the hot gas series dehumidification heating mode, the opening degree increasing control is executed, similarly to the hot gas series dehumidification heating mode.

[0259] In addition, in the low-temperature side heat medium circuit 40 in the single hot gas dehumidification heating mode, the control device 60 stops the low-temperature side pump 41.

[0260] In the indoor air conditioning unit 50 in the single hot gas dehumidifying heating mode, the control device 60 controls the blowing capacity of the indoor blower 52, the opening degree of the air mix door 54, the inside / outside air switching device 53, and the operation of the blowing mode door, in the same way as in the single cooling mode. The control device 60 also controls the operation of other control target devices as appropriate.

[0261] Therefore, in the heat pump cycle 10 in the single hot gas series dehumidification heating mode, the state of the refrigerant changes as shown in the Mollier diagram of Fig. 12. Note that Fig. 12 shows an example in which the saturation temperature of the refrigerant in the outdoor heat exchanger 15 is higher than the outdoor air temperature Tam.

[0262] The flow of the discharged refrigerant (point a12 in FIG. 12) discharged from 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 indoor condenser 13 and dissipates heat to the blown air (from point a12 to point b121 in FIG. 12). As a result, the blown air that has been cooled and dehumidified in the indoor evaporator 18 is reheated.

[0263] The refrigerant flowing out from the indoor condenser 13 flows into the heating expansion valve 14a and is depressurized (from point b121 to point b122 in FIG. 12). The refrigerant depressurized by the heating expansion valve 14a flows into the outdoor heat exchanger 15. In the example shown in FIG. 12, the refrigerant that flows into the outdoor heat exchanger 15 exchanges heat with outside air to reduce enthalpy (from point b122 to point b123 in FIG. 12).

[0264] The flow of the refrigerant that flows in from the outdoor heat exchanger 15 is branched at a four-way joint 12x. One of the refrigerant branches at the four-way joint 12x flows into the cooling expansion valve 14b and is reduced in pressure (from point b123 to point f12 in FIG. 12).

[0265] The refrigerant decompressed by the cooling expansion valve 14b flows into the indoor evaporator 18 and evaporates through heat exchange with the air blown from the indoor blower 52, as in the hot gas dehumidification heating mode (from point f12 to point e12 in FIG. 12). This cools and dehumidifies the air. The refrigerant flowing out of the indoor evaporator 18 flows into one inlet of the fifth three-way joint 12e via the second check valve 16b.

[0266] The other refrigerant branched at the four-way joint 12x flows into the cooling expansion valve 14c, as in the hot gas heating mode, where it is reduced in pressure (from point b123 to point c12 in Figure 12), and flows into the other inlet of the sixth three-way joint 12f.

[0267] The other refrigerant branched at the first three-way joint 12a flows into the bypass passage 21c. The refrigerant that flows into the bypass passage 21c is flow-regulated and depressurized by the bypass-side flow control valve 14d (from point a12 to point d12 in FIG. 12) in the same manner as in the hot gas heating mode. The refrigerant depressurized by the bypass-side flow control valve 14d flows into one inlet of the sixth three-way joint 12f.

[0268] The refrigerant flowing out from the sixth three-way joint 12f flows into the other inlet of the fifth three-way joint 12e. The refrigerant flowing out from the fifth three-way joint 12e flows into the accumulator 23. The refrigerant flowing into the accumulator 23 is mixed more homogeneously (point e12 in FIG. 12). The refrigerant flowing out from the accumulator 23 is sucked into the compressor 11 and compressed again.

[0269] Here, in Fig. 12, the pressure of the refrigerant decompressed by the cooling expansion valve 14c (point c12 in Fig. 12) is shown as a value lower than the pressure of the refrigerant decompressed by the cooling expansion valve 14b (point f12 in Fig. 12), but is not limited to this. The pressure of the refrigerant decompressed by the cooling expansion valve 14c may be higher than or equal to the pressure of the refrigerant decompressed by the cooling expansion valve 14b.

[0270] As described above, the heat pump cycle 10 in the hot gas serial dehumidification heating mode is switched to a refrigerant circuit in which refrigerants with different enthalpies, such as the refrigerant with low enthalpy flowing out from the chiller 20 (point c12 in Figure 12), the refrigerant with high enthalpy flowing out from the bypass passage 21c (point d12 in Figure 12), and the refrigerant flowing out from the indoor evaporator 18, are mixed and sucked into the compressor 11.

[0271] Therefore, in the hot gas serial dehumidification heating mode, the heating expansion valve 14a and the cooling expansion valve 14c function as a heating section side pressure reducing section, the sixth three-way joint 12f functions as a mixing section, the four-way joint 12x functions as an auxiliary branch section, the cooling expansion valve 14b functions as an auxiliary heating section side pressure reducing section, and the indoor evaporator 18 functions as an evaporation section.

[0272] In the heat pump cycle 10 in the hot gas series dehumidification heating mode, the cycle balance is controlled by adjusting the throttle opening of the heating expansion valve 14a and the cooling expansion valve 14c. The rest is the same as in the hot gas series dehumidification heating mode.

[0273] That is, in the hot gas in-line dehumidifying and heating mode of this embodiment, the suction refrigerant pressure Ps is controlled by adjusting the refrigerant discharge capacity of the compressor 11. Furthermore, the discharge refrigerant pressure Pd is controlled by adjusting the throttle openings of the heating expansion valve 14a, the cooling expansion valve 14c, and the bypass side flow control valve 14d.

[0274] Therefore, in the hot gas series dehumidification heating mode, the operation of at least one of the compressor 11, the cooling expansion valve 14c, and the bypass side flow control valve 14d is controlled so that the blowing air temperature TAV approaches the target blowing temperature TAO and the dryness Rx of the suction refrigerant approaches the reference dryness KRx.

[0275] In the interior air conditioning unit 50 in the single hot gas serial dehumidifying and heating mode, the blown air cooled and dehumidified in the interior evaporator 18 is reheated in the interior condenser 13 and blown into the vehicle cabin. This realizes dehumidifying and heating the vehicle cabin.

[0276] Here, in the hot gas serial dehumidification heating mode, as in the hot gas dehumidification heating mode, the refrigerant discharge capacity of the compressor 11 must be adjusted so that the temperature of the blown air can be reheated to the desired temperature in the heating section without causing frosting of the indoor evaporator 18.

[0277] In contrast, in the single hot gas series dehumidifying and heating mode of the present embodiment, a refrigerant with a relatively high enthalpy is caused to flow into the mixing section via the bypass passage 21c. This makes it possible to increase the amount of heat dissipated from the discharged refrigerant to the blown air in the indoor condenser 13 without causing frost formation in the indoor evaporator 18, as in the single hot gas series dehumidifying and heating mode.

[0278] As a result, in the single hot gas series dehumidification and heating mode, the blown air can be heated with a heating capacity higher than that in the series dehumidification and heating mode.

[0279] (f-2) Cooling hot gas serial dehumidification heating mode In the cooling hot gas series dehumidification heating mode, the control device 60 operates the low-temperature side pump 41 to exert a predetermined standard pumping capacity in comparison with the single hot gas series dehumidification heating mode. Therefore, in the heat pump cycle 10 in the cooling hot gas series dehumidification heating mode, the refrigerant flowing into the chiller 20 absorbs heat from the low-temperature side heat medium. This causes the low-temperature side heat medium to be cooled. Other operations are the same as those in the single hot gas series dehumidification heating mode.

[0280] Therefore, in the cooling hot gas series dehumidification heating mode, like the single hot gas series dehumidification heating mode, the blown air is heated with a heating capacity higher than that of the series dehumidification heating mode, and dehumidification and heating of the vehicle interior can be realized. Furthermore, in the cooling hot gas dehumidification heating mode, in the low-temperature side heat medium circuit 40, the low-temperature side heat medium cooled by the chiller 20 flows through the coolant passage 70a of the battery 70. This allows the battery 70 to be cooled.

[0281] As described above, in the vehicle air conditioner 1 of this embodiment, by switching the operation mode, it is possible to perform comfortable air conditioning for the vehicle interior and appropriate temperature adjustment of the battery 70, which is an on-board device.

[0282] Incidentally, in the heat pump cycle 10 in the (d) hot gas heating mode, (e) hot gas dehumidification heating mode, and (f) hot gas serial dehumidification heating mode, the refrigerant circuit is switched to one in which refrigerants with different enthalpies are mixed and sucked into the compressor 11.

[0283] In these operation modes, it is necessary to appropriately adjust the workload of the compressor so that the blown air can be appropriately heated. At the same time, it is necessary to appropriately adjust the throttle opening of the heating section side pressure reducing section and the bypass side flow control valve so that the state of the suction refrigerant sucked into the compressor 11 is appropriate.

[0284] The reason is that if the state of the suctioned refrigerant is not maintained in an appropriate state, it will have an adverse effect on the durable life of the compressor 11. For example, if the suctioned refrigerant is a gas-liquid two-phase refrigerant with a dryness Rx that is lower than necessary, this may lead to liquid compression in the compressor 11. Also, if the suctioned refrigerant is a gas-phase refrigerant with a superheat degree SH that is higher than necessary, the temperature of the compressor 11 may abnormally increase.

[0285] Therefore, in the vehicle air conditioning system 1 of this embodiment, during the above-mentioned operation mode, the operation of the compressor 11, the cooling expansion valve 14c, and the bypass side flow control valve 14d is controlled so that the blowing air temperature TAV approaches the target blowing temperature TAO and the dryness Rx of the intake refrigerant approaches the reference dryness KRx.

[0286] However, in an actual heat pump cycle 10, the refrigerant flow rate adjustment range in the heating section-side pressure reduction section is different from the refrigerant flow rate adjustment range in the bypass-side flow rate adjustment valve 14d. Therefore, if the throttle opening of either the heating section-side pressure reduction section or the bypass-side flow rate adjustment valve 14d approaches the fully open state and the flow rate adjustment capability decreases, it may become impossible to maintain the state of the suctioned refrigerant in an appropriate state.

[0287] For example, a refrigerant path extending from the first three-way joint 12a to the sixth three-way joint 12f via the indoor condenser 13, the dehumidification on-off valve 22a, the cooling expansion valve 14c, and the chiller 20 is defined as a first refrigerant path. side The refrigerant path leading to the sixth three-way joint 12f via the flow rate control valve 14d is defined as a second refrigerant path, and the refrigerant path leading to the sixth three-way joint 12f via the first three-way joint 12a, the indoor condenser 13, the heating expansion valve 14a, the outdoor heat exchanger 15, the first check valve 16a, and the chiller 20 is defined as a third refrigerant path.

[0288] The first refrigerant path is provided with the indoor condenser 13 and the chiller 20. As a result, as the pressure loss caused in the refrigerant flowing through the indoor condenser 13 and the chiller 20 increases, the heating unit side front-rear pressure difference, which is the refrigerant pressure on the upstream side of the heating unit side decompression unit minus the refrigerant pressure on the downstream side, decreases. side There is no configuration for reducing the bypass-side differential pressure obtained by subtracting the refrigerant pressure on the downstream side from the refrigerant pressure on the upstream side of the flow rate adjustment valve 14d.

[0289] For this reason, in the (d) hot gas heating mode, the refrigerant flow rate adjustment range in the heating section side pressure reduction section is likely to be narrower than the refrigerant flow rate adjustment range in the bypass side flow rate adjustment valve 14d. As a result, the flow rate adjustment capability of the heating section side pressure reduction section may become lower than the flow rate adjustment capability of the bypass side flow rate adjustment valve 14d.

[0290] In addition, in an operation mode in which the blown air is dehumidified, a portion of the refrigerant flowing out from the indoor condenser 13 must be made to flow from the four-way joint 12x into the indoor evaporator 18. At this time, the flow rate of the refrigerant flowing into the indoor evaporator 18 is determined by the heat exchange load with the blown air. Therefore, the flow rate of the refrigerant flowing out from the four-way joint 12x to the chiller 20 is restricted.

[0291] Therefore, in the (e) hot gas dehumidification heating mode and the (f) hot gas serial dehumidification heating mode, the refrigerant flow rate adjustment range in the heating section side pressure reduction section is narrower than the refrigerant flow rate adjustment range in the bypass side flow rate adjustment valve 14d. Therefore, the flow rate adjustment capability of the heating section side pressure reduction section may become lower than the flow rate adjustment capability of the bypass side flow rate adjustment valve 14d.

[0292] Further, the third refrigerant path is provided with the indoor condenser 13, the outdoor heat exchanger 15, the first check valve 16a, and the chiller 20. Therefore, the pressure difference on the heating section side decreases as the pressure loss caused in the refrigerant flowing through the indoor condenser 13, the outdoor heat exchanger 15, the first check valve 16a, and the chiller 20 increases. On the other hand, the second refrigerant path is not provided with a configuration for reducing the pressure difference on the bypass side.

[0293] Furthermore, in the (f) hot gas in-line dehumidifying and heating mode, the refrigerant pressure in the outdoor heat exchanger 15 is adjusted to adjust the heating capacity of the blown air in the indoor condenser 13. That is, in the (f) hot gas in-line dehumidifying and heating mode, the refrigerant pressure in the outdoor heat exchanger 15 is made lower than the refrigerant pressure in the indoor condenser 13.

[0294] Therefore, in the (f) hot gas in-line dehumidifying heating mode, the pressure difference across the cooling expansion valve 14b is smaller than in the (d) hot gas heating mode or the (e) hot gas dehumidifying heating mode, and the flow rate adjustment range of the cooling expansion valve 14b is narrower.

[0295] Therefore, in the (f) hot gas in-line dehumidifying and heating mode, the refrigerant flow rate adjustment range in the heating section side pressure reduction section becomes narrower than the refrigerant flow rate adjustment range in the bypass side flow rate adjustment valve 14d. As a result, the flow rate adjustment capability of the heating section side pressure reduction section may become lower than the flow rate adjustment capability of the bypass side flow rate adjustment valve 14d.

[0296] Furthermore, according to the inventors' investigations, in order to adjust the heating capacity of the blown air while changing the refrigerant discharge capacity of the compressor 11, it may be necessary to simultaneously increase the throttle opening of both the cooling expansion valve 14c and the bypass side flow control valve 14d.

[0297] That is, in the (d) hot gas heating mode, (e) hot gas dehumidification heating mode, and (f) hot gas serial dehumidification heating mode of this embodiment, even if it is difficult to increase the flow rate of the refrigerant flowing from the heating section side decompression section side to the sixth three-way joint 12f, the throttle opening of the bypass side flow control valve 14d may be increased. As a result, the suction refrigerant may become a gas phase refrigerant with a higher superheat degree SH than necessary.

[0298] In contrast, in the (d) hot gas heating mode, (e) hot gas dehumidification heating mode, and (f) hot gas serial dehumidification heating mode of this embodiment, upper limit opening control is performed.

[0299] According to this, when the throttle opening of the heating section side pressure reducing section is equal to or greater than the reference limit opening, the throttle opening of the bypass side flow rate adjustment valve 14d can be set to the upper limit opening or less. In other words, when the throttle opening of the heating section side pressure reducing section is equal to or larger than the reference limit opening, the throttle opening of the bypass side flow rate adjustment valve 14d can be reduced. In other words, when it becomes difficult to increase the flow rate of the refrigerant with lower enthalpy flowing from the heating section side pressure reduction section side into the sixth three-way joint 12f, it is possible to limit the flow rate of the refrigerant with higher enthalpy flowing from the bypass side flow control valve 14d side into the sixth three-way joint 12f.

[0300] Therefore, it is possible to prevent the suctioned refrigerant from becoming a gas-phase refrigerant with an excessively high degree of superheat SH. As a result, even in a heat pump cycle device in which refrigerants with different enthalpies are mixed and sucked into the compressor 11, it is possible to reliably protect the compressor 11.

[0301] In addition, since the refrigerant flowing through the second refrigerant path is in a gas phase, it is possible that the pressure loss generated in the refrigerant flowing through the second refrigerant path is greater than the pressure loss generated in the refrigerant flowing through the first refrigerant path. For example, in a heat pump cycle device in which a pipe thinner than the other pipes is used as the bypass passage 21c, the pressure loss generated in the refrigerant flowing through the second refrigerant path is likely to be greater than the pressure loss generated in the refrigerant flowing through the first refrigerant path.

[0302] Similarly, it is also possible that the pressure loss occurring in the refrigerant flowing through the second refrigerant path becomes larger than the pressure loss occurring in the refrigerant flowing through the third refrigerant path.

[0303] In this case, the flow rate control capacity of the bypass-side flow control valve 14d may become lower than the flow rate control capacity of the heating-part-side pressure reduction section. That is, even if it is difficult to increase the flow rate of the refrigerant flowing from the bypass-side flow control valve 14d side to the sixth three-way joint 12f, the throttle opening of the heating-part-side pressure reduction section may be increased. As a result, the suctioned refrigerant may become a gas-liquid two-phase refrigerant with a lower dryness Rx than necessary.

[0304] In contrast, in the (d) hot gas heating mode, (e) hot gas dehumidification heating mode, and (f) hot gas serial dehumidification heating mode of this embodiment, upper limit opening control is performed.

[0305] According to this, when the throttle opening of the bypass side flow rate adjustment valve 14d is equal to or greater than the reference limit opening, the throttle opening of the heating part side pressure reduction part can be set to the upper limit opening or less. In other words, when the throttle opening of the bypass side flow rate adjustment valve 14d is equal to or larger than the reference limit opening, the throttle opening of the heating part side pressure reduction part can be reduced. In other words, when it becomes difficult to increase the flow rate of the refrigerant with higher enthalpy flowing from the bypass side flow control valve 14d side into the sixth three-way joint 12f, it is possible to limit the flow rate of the refrigerant with lower enthalpy flowing from the heating section side pressure reduction section side into the sixth three-way joint 12f.

[0306] Therefore, it is possible to prevent the suctioned refrigerant from becoming a gas-liquid two-phase refrigerant with an unnecessarily low dryness Rx. As a result, even in a heat pump cycle device in which refrigerants with different enthalpies are mixed and sucked into the compressor 11, it is possible to reliably protect the compressor 11.

[0307] That is, in the vehicle air conditioning device 1 of this embodiment, by performing upper limit opening control, even if refrigerants with different enthalpies are mixed and sucked into the compressor 11, the state of the sucked refrigerant can be maintained in an appropriate state, thereby reliably protecting the compressor 11.

[0308] In the upper limit opening control of this embodiment, when the opening of either the heating section side pressure reducing section or the bypass side flow control valve 14d is equal to or greater than the reference limit opening, it is determined that the flow control capacity of the other is equal to or less than the reference control capacity. This makes it possible to easily and accurately estimate the flow control capacity of one of the variable throttle mechanisms using the opening.

[0309] In the upper limit opening control of this embodiment, as the opening of one of the heating section side pressure reducing section and the bypass side flow rate adjustment valve 14d increases, the upper limit opening of the other is set to a lower value. This allows the upper limit opening of the other variable throttling mechanism to be set to a lower value as it becomes more difficult to increase the flow rate of the refrigerant flowing from one variable throttling mechanism to the sixth three-way joint 12f. Therefore, the compressor 11 can be protected more reliably.

[0310] In addition, in the (e) hot gas dehumidification heating mode and the (f) hot gas serial dehumidification heating mode of this embodiment, the opening degree is increased.

[0311] According to this, when it becomes difficult to increase the flow rate of the refrigerant with low enthalpy flowing from the cooling expansion valve 14c side into the sixth three-way joint 12f, the flow rate of the refrigerant with relatively low enthalpy can be merged with the suctioned refrigerant via the cooling expansion valve 14b and the indoor evaporator 18. Therefore, it is possible to effectively prevent the superheat degree SH of the suctioned refrigerant from becoming higher than necessary.

[0312] Here, in the vehicle air conditioner 1 of the present embodiment, an example has been described in which the first target subcooling degree SCO1 is determined so that the dryness Rx of the suction refrigerant approaches the reference dryness KRx during the (d) hot gas heating mode, but the present invention is not limited to this. The first target subcooling degree SCO1 may be determined so that the superheat degree SH of the suction refrigerant approaches a predetermined reference superheat degree KSH during the (d) hot gas heating mode.

[0313] Similarly, in (e) the hot gas dehumidification heating mode and (f) the hot gas serial dehumidification heating mode, the throttle opening of the cooling expansion valve 14c may be changed so that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH.

[0314] That is, in the vehicle air conditioning device 1 of this embodiment, even if the operation of at least one of the compressor 11, the heating section side pressure reduction section, and the bypass side flow control valve 14d is controlled so that the blowing air temperature TAV approaches the target blowing temperature TAO and the superheat degree SH of the intake refrigerant approaches the reference superheat degree KSH, the compressor 11 can be reliably protected.

[0315] Second embodiment In this embodiment, an example in which the control mode of the upper limit opening control is changed from that of the first embodiment will be described. The up / down opening control of this embodiment will be described using the flowchart of Fig. 13. Fig. 13 shows the control process corresponding to Fig. 6 described in the first embodiment.

[0316] In step S11a of this embodiment, a control zone for the upper limit opening control is determined using a valve differential pressure ratio, which is the ratio of the smaller of the heated section side differential pressure and the bypass side differential pressure to the larger of the two.

[0317] Specifically, as shown in the control characteristics diagram in step S11a of Fig. 13, when the valve differential pressure ratio is greater than a predetermined reference valve differential pressure ratio (90% in this embodiment), the control zone is determined to be zone 0. Then, when the valve differential pressure ratio is equal to or greater than the reference valve differential pressure, the control zones are determined in the order of zone 1, zone 2, and zone 3 as the valve differential pressure ratio decreases. The subsequent control aspects of the upper limit opening control are the same as those in the first embodiment.

[0318] As described above, in the variable throttle mechanism, the flow rate adjustment capability decreases as the differential pressure across the valve decreases. Therefore, in the upper limit opening control of this embodiment, when the valve differential pressure ratio is equal to or lower than the reference valve differential pressure ratio, it is determined that the flow rate adjustment capability of the variable throttle mechanism that is the smaller of the heated section side differential pressure across the valve and the bypass side differential pressure across the valve is equal to or lower than the reference adjustment capability.

[0319] In addition, in step S13, which is the upper limit opening degree determining section of this embodiment, the upper limit opening degree is determined to be a low value as the valve differential pressure ratio decreases. Other configurations and operations of the vehicle air conditioner 1 are similar to those of the first embodiment.

[0320] Therefore, the vehicle air conditioner 1 of this embodiment can also provide the same effects as those of the first embodiment. That is, by switching the operation mode, it is possible to provide comfortable air conditioning for the vehicle interior and appropriate temperature adjustment for the battery 70, which is an on-board device. At this time, even if refrigerants with different enthalpies are mixed and sucked into the compressor 11, the state of the sucked refrigerant can be maintained in an appropriate state, and the compressor 11 can be reliably protected.

[0321] In the upper limit opening control of this embodiment, when the valve differential pressure ratio is equal to or less than the reference valve differential pressure ratio, it is determined that the flow rate adjustment capacity of the variable throttling mechanism having the smaller of the heated section side front-to-rear differential pressure and the bypass side front-to-rear differential pressure is equal to or less than the reference adjustment capacity. This makes it possible to easily and accurately estimate the flow rate adjustment capacity of the variable throttling mechanism having the smaller front-to-rear differential pressure by relatively comparing the heated section side front-to-rear differential pressure and the bypass side front-to-rear differential pressure.

[0322] Furthermore, since the opening ratio is used to grasp the flow rate adjustment capability of the variable throttle mechanism with the smaller front-to-rear differential pressure, there is no need to detect or estimate the throttle opening of each variable throttle mechanism. Therefore, the heating section side pressure reduction section or bypass side flow rate adjustment valve 14d is not limited to a variable throttle mechanism having a stepping motor as a drive section, and for example, a variable throttle mechanism having a brushless DC motor as a drive section may be adopted.

[0323] In the upper limit opening control of this embodiment, the upper limit opening is set to a lower value as the valve differential pressure ratio decreases. This allows the upper limit opening of one variable throttling mechanism to be set to a lower value as it becomes more difficult to increase the flow rate of the refrigerant flowing from the other variable throttling mechanism. This makes it possible to more reliably protect the compressor 11.

[0324] Of course, in the vehicle air conditioning device 1 of this embodiment, even if the operation of at least one of the compressor 11, the heating section side pressure reduction section, and the bypass side flow control valve 14d is controlled so that the blowing air temperature TAV approaches the target blowing temperature TAO and the superheat degree SH of the intake refrigerant approaches the reference superheat degree KSH, the compressor 11 can be reliably protected, as in the first embodiment.

[0325] Third embodiment In this embodiment, an example in which the operation modes in (d) hot gas heating mode, (e) hot gas dehumidification heating mode, and (f) hot gas serial dehumidification heating mode are changed from those in the first embodiment will be described. The detailed operation of each operation mode will be described below.

[0326] (d) Hot gas heating mode In the hot gas heating mode of this embodiment, the controller 60 adjusts the opening ratio of the throttle opening of the heating section side pressure reduction section to the throttle opening of the bypass side flow control valve 14d so that the dryness Rx of the suction refrigerant approaches the reference dryness KRx. Specifically, the opening ratio is adjusted based on the dryness Rx of the suction refrigerant by referring to a control map stored in advance in the controller 60. The throttle opening of the heating section side pressure reduction section in the hot gas heating mode is the throttle opening of the cooling side expansion valve 14c.

[0327] In the control map of this embodiment, an opening ratio that provides an appropriate flow rate ratio is stored in advance, as shown in the control characteristic diagram of Fig. 14. When the dryness Rx of the suction refrigerant is larger than the reference dryness KRx, the control device 60 increases the opening ratio. When the dryness Rx of the suction refrigerant is smaller than the reference dryness KRx, the control device 60 decreases the opening ratio.

[0328] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the discharge refrigerant pressure Pd approaches the target high pressure PDO. Other operations are similar to those of the first embodiment.

[0329] Therefore, in the hot gas heating mode of this embodiment, as in the first embodiment, the heat generated by the work of the compressor 11 can be effectively used to heat the blown air, thereby realizing heating of the vehicle cabin. Also, in the hot gas heating mode of this embodiment, as in the first embodiment, the single hot gas heating mode, the cooling hot gas heating mode, and the warming hot gas heating mode can be executed.

[0330] (e) Hot gas dehumidification heating mode In the hot gas dehumidification heating mode, the control device 60 adjusts the opening ratio in the same manner as in the hot gas heating mode. The throttle opening of the heating section side pressure reducing section in the hot gas dehumidification heating mode is the throttle opening of the cooling side expansion valve 14c.

[0331] Similarly to the hot gas dehumidifying heating mode of the first embodiment, the controller 60 controls the refrigerant discharge capacity of the compressor 11 so that the suction refrigerant pressure Ps approaches a predetermined second target low pressure PSO2. The controller 60 also changes the throttle opening of the cooling expansion valve 14b so that the discharge refrigerant pressure Pd approaches the target high pressure PDO. Other operations are the same as those of the first embodiment.

[0332] Therefore, in the hot gas dehumidifying heating mode of this embodiment, the blown air can be heated with a heating capacity higher than that of the series dehumidifying heating mode, and dehumidifying and heating the vehicle interior can be realized, as in the first embodiment. Also, in the hot gas dehumidifying heating mode of this embodiment, the single hot gas dehumidifying heating mode and the cooled hot gas dehumidifying heating mode can be executed, as in the first embodiment.

[0333] (f) Hot gas serial dehumidification heating mode In the hot gas dehumidification heating mode, the control device 60 adjusts the opening ratio in the same manner as in the hot gas heating mode. The throttle opening of the heating section side pressure reducing section in the hot gas dehumidification heating mode is the total throttle opening of the heating expansion valve 14a and the cooling expansion valve 14c, as in the first embodiment.

[0334] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the suction refrigerant pressure Ps approaches a predetermined second target low pressure PSO2, similarly to the hot gas dehumidification heating mode of the first embodiment.

[0335] Similarly to the serial dehumidification heating mode, the control device 60 determines the throttle opening of the heating expansion valve 14a and the cooling expansion valve 14b. Furthermore, in this embodiment, the total throttle opening of the heating expansion valve 14a and the cooling expansion valve 14b is changed so that the discharge refrigerant pressure Pd approaches the target high pressure PDO. Other operations are the same as those in the first embodiment.

[0336] Therefore, in the hot gas series dehumidifying and heating mode of this embodiment, the blown air can be heated with a heating capacity higher than that in the series dehumidifying and heating mode, as in the first embodiment, to realize dehumidifying and heating of the vehicle interior. Also, in the hot gas series dehumidifying and heating mode of this embodiment, the single hot gas series dehumidifying and heating mode and the cooled hot gas series dehumidifying and heating mode can be executed, as in the first embodiment.

[0337] The operations of (a) the cooling mode, (b) the serial dehumidification heating mode, and (c) the outside air heat absorption heating mode are the same as those in the first embodiment. Therefore, in the vehicle air conditioner 1 of this embodiment, by switching the operation mode, it is possible to perform comfortable air conditioning in the vehicle cabin and appropriate temperature adjustment of the battery 70, which is an on-board device.

[0338] Furthermore, in the (d) hot gas heating mode, (e) hot gas dehumidification heating mode, and (f) hot gas serial dehumidification heating mode of this embodiment, the opening ratio is adjusted so that the dryness Rx of the suction refrigerant approaches the reference dryness KRx. This allows the throttle opening of the heating section side pressure reducing section and the bypass side flow control valve 14d to be changed within a range in which the state of the suction refrigerant is appropriate, regardless of the refrigerant discharge capacity of the compressor 11.

[0339] Therefore, it is possible to prevent the dryness fraction Rx of the suction refrigerant from becoming lower than necessary. As a result, even in a heat pump cycle device in which refrigerants with different enthalpies are mixed and flown into the compressor 11, it is possible to reliably protect the compressor 11.

[0340] Here, in the vehicle air conditioner 1 of the present embodiment, the opening ratio is adjusted so that the dryness Rx of the intake refrigerant approaches the reference dryness KRx in the (d) hot gas heating mode, but the present invention is not limited to this. For example, the first target subcooling degree SCO1 may be determined so that the superheat degree SH of the intake refrigerant approaches the reference superheat degree KSH in the (d) hot gas heating mode.

[0341] In this case, the control device 60 increases the opening ratio when the superheat degree SH of the suction refrigerant is greater than the reference superheat degree KSH, and decreases the opening ratio when the superheat degree SH of the suction refrigerant is less than the reference superheat degree KSH. This also applies to the (e) hot gas dehumidification heating mode and the (f) hot gas serial dehumidification heating mode.

[0342] (Fourth embodiment) In this embodiment, the heat pump cycle device according to the present disclosure is applied to a vehicle air conditioner 1a. The vehicle air conditioner 1a includes a heat pump cycle 10a. In the heat pump cycle 10a, the accumulator 23 and the like are eliminated from the heat pump cycle 10 described in the first embodiment, and a receiver 24 and the like are adopted.

[0343] In the heat pump cycle 10a, the inlet side of the receiver 24 is connected to the other outlet of the second three-way joint 12b. The refrigerant passage from the other outlet of the second three-way joint 12b to the inlet of the receiver 24 is the inlet-side passage 21d. The first inlet-side opening / closing valve 22c and the seventh three-way joint 12g are arranged in the inlet-side passage 21d. The receiver 24 is a high-pressure side gas-liquid separation section that separates the refrigerant that has flowed into it into gas and liquid and stores the separated liquid-phase refrigerant as surplus refrigerant for the cycle. The receiver 24 causes the separated liquid-phase refrigerant to flow downstream from the liquid-phase refrigerant outlet.

[0344] The first inlet side on-off valve 22c is an on-off valve that opens and closes the inlet side passage 21d. More specifically, the first inlet side on-off valve 22c opens and closes the refrigerant passage in the inlet side passage 21d that extends from the other outlet of the second three-way joint 12b to one inlet of the seventh three-way joint 12g. The first inlet side on-off valve 22c is a refrigerant circuit switching unit.

[0345] Further, one of the outlets of the second three-way joint 12b is connected to one of the inlet sides of the eighth three-way joint 12h. A second inlet side opening / closing valve 22d is disposed in the refrigerant passage extending from one of the outlets of the second three-way joint 12b to one of the inlet sides of the eighth three-way joint 12h. The second inlet side opening / closing valve 22d opens and closes the refrigerant passage extending from one of the outlets of the second three-way joint 12b to one of the inlet sides of the eighth three-way joint 12h. The second inlet side opening / closing valve 22d is a refrigerant circuit switching unit.

[0346] The inlet side of the heating expansion valve 14a is connected to the outlet of the eighth three-way joint 12h. The other inlet side of the seventh three-way joint 12g arranged in the inlet-side passage 21d is connected to one outlet of the third three-way joint 12c connected to the outlet side of the outdoor heat exchanger 15 via the first check valve 16a.

[0347] The other inlet side of the eighth three-way joint 12h is connected to the liquid phase refrigerant outlet of the receiver 24. The refrigerant passage leading from the outlet of the receiver 24 to the other inlet of the eighth three-way joint 12h is the outlet-side passage 21e. The ninth three-way joint 12i and the third check valve 16c are arranged in the outlet-side passage 21e.

[0348] The third check valve 16c allows the refrigerant to flow from the ninth three-way joint 12i side to the eighth three-way joint 12h side and prohibits the refrigerant from flowing from the eighth three-way joint 12h side to the ninth three-way joint 12i side.

[0349] The other outlet of the ninth three-way joint 12i is connected to the inlet side of a tenth three-way joint 12j. The refrigerant inlet side of an indoor evaporator 18 is connected to one outlet of the tenth three-way joint 12j via a cooling expansion valve 14b. The other outlet of the tenth three-way joint 12j is connected to the inlet side of a refrigerant passage of a chiller 20 via a cooling expansion valve 14c.

[0350] Furthermore, in the heat pump cycle 10a, the outlet of the fourth three-way joint 12d is connected to the suction port side of the compressor 11. The rest of the configuration of the vehicle air conditioner 1a is similar to that of the vehicle air conditioner 1 described in the first embodiment.

[0351] Next, the operation of the vehicle air conditioner 1a of this embodiment with the above configuration will be described. In the vehicle air conditioner 1a of this embodiment, various operation modes are switched in the same manner as in the first embodiment in order to condition the air in the vehicle cabin and adjust the temperature of the battery 70. The detailed operation of each operation mode will be described below.

[0352] (a-1) Single cooling mode In the heat pump cycle 10a in the cooling only mode, the controller 60 fully opens the heating expansion valve 14a, throttles the cooling expansion valve 14b, fully closes the cooling expansion valve 14c, and fully closes the bypass-side flow control valve 14d. The controller 60 also closes the heating on-off valve 22b, closes the first inlet on-off valve 22c, and opens the second inlet on-off valve 22d.

[0353] Therefore, in the heat pump cycle 10a in the cooling only mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the order of the indoor condenser 13, the heating expansion valve 14a in the fully open state, the outdoor heat exchanger 15, the receiver 24, the cooling expansion valve 14b in the throttling state, the indoor evaporator 18, and the suction port of the compressor 11. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0354] Therefore, in the heat pump cycle 10a in the sole cooling mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 and the outdoor heat exchanger 15 function as a condenser, and the indoor evaporator 18 functions as an evaporator. The indoor air conditioning unit 50 operates in the same manner as in the sole cooling mode of the first embodiment.

[0355] As a result, in the single cooling mode, cooling of the vehicle interior is achieved in the same manner as in the single cooling mode of the first embodiment.

[0356] (a-2) Cooling mode In the heat pump cycle 10a in the cooling / air-cooling mode, the controller 60 controls the cooling expansion valve 14c to be in the throttling state in contrast to the single cooling mode.

[0357] Therefore, in the heat pump cycle 10a in the cooling / cooling mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single cooling mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the order of the indoor condenser 13, the heating expansion valve 14a in the fully open state, the outdoor heat exchanger 15, the receiver 24, the cooling expansion valve 14c in the throttling state, the chiller 20, and the suction port of the compressor 11. In other words, 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. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0358] Therefore, in the heat pump cycle 10a in the cooling / air-conditioning mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 and the outdoor heat exchanger 15 function as condensers, and the indoor evaporator 18 and the chiller 20 function as evaporators. Also, the low-temperature side heat medium circuit 40 and the indoor air-conditioning unit 50 operate in the same manner as in the single cooling mode of the first embodiment.

[0359] As a result, in the cooling / air-cooling mode, cooling of the battery 70 and cooling of the vehicle compartment are achieved, similarly to the cooling / air-cooling mode of the first embodiment.

[0360] (b-1) Single series dehumidification and heating mode In the heat pump cycle 10a in the single serial dehumidification and heating mode, the controller 60 throttles the heating expansion valve 14a, throttles the cooling expansion valve 14b, fully closes the cooling expansion valve 14c, and fully closes the bypass-side flow control valve 14d. The controller 60 also closes the heating on-off valve 22b, closes the first inlet side on-off valve 22c, and opens the second inlet side on-off valve 22d.

[0361] Therefore, in the heat pump cycle 10a in the single serial dehumidifying and heating mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the order of the indoor condenser 13, the heating expansion valve 14a in the throttling state, the outdoor heat exchanger 15, the receiver 24, the cooling expansion valve 14b in the throttling state, the indoor evaporator 18, and the suction port of the compressor 11. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0362] Therefore, in the heat pump cycle 10a in the single series dehumidifying and heating mode, the indoor condenser 13 and the outdoor heat exchanger 15 function as a condenser, and the indoor evaporator 18 functions as an evaporator, forming a vapor compression refrigeration cycle. The indoor air conditioning unit 50 operates in the same manner as in the single cooling mode of the first embodiment.

[0363] As a result, in the single series dehumidifying and heating mode, dehumidifying and heating the vehicle cabin is realized as in the single series dehumidifying and heating mode of the first embodiment. Here, since the heat pump cycle 10a has the receiver 24, the single series dehumidifying and heating mode is performed in a temperature range in which the saturation temperature of the refrigerant in the exterior heat exchanger 15 is higher than the outside air temperature Tam.

[0364] (b-2) Cooling series dehumidification heating mode In the heat pump cycle 10a in the cooling series dehumidification heating mode, the controller 60 controls the cooling expansion valve 14c to the throttling state, unlike the single series dehumidification heating mode.

[0365] Therefore, in the heat pump cycle 10a in the cooling serial dehumidification heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single serial dehumidification heating mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the order of the indoor condenser 13, the heating expansion valve 14a in the fully open state, the outdoor heat exchanger 15, the receiver 24, the cooling expansion valve 14c in the throttling state, the chiller 20, and the suction port of the compressor 11. In other words, the indoor evaporator 18 and the chiller 20 are switched to a refrigerant circuit connected in parallel with respect to the refrigerant flow. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0366] Therefore, in the heat pump cycle 10a in the cooling serial dehumidification heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 and the outdoor heat exchanger 15 function as condensers, and the indoor evaporator 18 and the chiller 20 function as evaporators. Also, the low-temperature side heat medium circuit 40 and the indoor air conditioning unit 50 operate in the same manner as in the cooling serial dehumidification heating mode of the first embodiment.

[0367] As a result, in the cooling series dehumidification heating mode, cooling of the battery 70 and dehumidification heating of the vehicle cabin are achieved, similarly to the cooling series dehumidification heating mode of the first embodiment. Here, since the heat pump cycle 10a has the receiver 24, the cooling series dehumidification heating mode is executed in a temperature range in which the saturation temperature of the refrigerant in the exterior heat exchanger 15 is higher than the outside air temperature Tam.

[0368] (c-1) Single outdoor air heat absorption heating mode In the heat pump cycle 10a in the single outdoor air heat absorption heating mode, the controller 60 throttles the heating expansion valve 14a, fully closes the cooling expansion valve 14b, fully closes the cooling expansion valve 14c, and fully closes the bypass side flow control valve 14d. The controller 60 also opens the heating on-off valve 22b, opens the first inlet side on-off valve 22c, and closes the second inlet side on-off valve 22d.

[0369] Therefore, in the heat pump cycle 10a in the single outdoor air heat absorption heating mode, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates in the order of the indoor condenser 13, the receiver 24, the heating expansion valve 14a in the throttling state, the outdoor heat exchanger 15, the heating passage 21b, and the suction port of the compressor 11. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0370] Therefore, in the heat pump cycle 10a in the single outdoor air heat absorption heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser and the outdoor heat exchanger 15 functions as an evaporator. Also, the indoor air conditioning unit 50 operates in the same manner as in the single outdoor air heat absorption heating mode of the first embodiment.

[0371] As a result, in the single outside air heat absorption heating mode, heating of the vehicle interior is achieved in the same manner as in the single outside air heat absorption heating mode of the first embodiment.

[0372] (c-2) Cooling outdoor air heat absorption heating mode In the heat pump cycle 10a in the cooling outdoor air heat absorption heating mode, the controller 60 controls the cooling expansion valve 14c to the throttling state, unlike the single outdoor air heat absorption heating mode.

[0373] Therefore, in the heat pump cycle 10a in the cooling outdoor air heat absorption heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single outdoor air heat absorption heating mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates through the indoor condenser 13, the receiver 24, the cooling expansion valve 14c in the throttling state, the chiller 20, and the suction port of the compressor 11 in that order. In other words, the refrigerant circuit is switched to one in which the outdoor heat exchanger 15 and the chiller 20 are connected in parallel with respect to the refrigerant flow. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0374] Therefore, in the heat pump cycle 10a in the cooled outdoor air heat absorption heating mode, a vapor compression refrigeration cycle is configured in which the indoor condenser 13 functions as a condenser and the outdoor heat exchanger 15 and the chiller 20 function as an evaporator. Also, the low-temperature side heat medium circuit 40 and the indoor air conditioning unit 50 operate in the same manner as in the cooled outdoor air heat absorption heating mode of the first embodiment.

[0375] As a result, in the cooled outside air heat absorption heating mode, cooling of the battery 70 and heating of the vehicle compartment are achieved, similarly to the cooled outside air heat absorption heating mode of the first embodiment.

[0376] (d-1) Single hot gas heating mode In the heat pump cycle 10a in the single hot gas heating mode, the controller 60 fully closes the heating expansion valve 14a, fully closes the cooling expansion valve 14b, throttles the cooling expansion valve 14c, and throttles the bypass-side flow control valve 14d. The controller 60 also closes the heating on-off valve 22b, opens the first inlet side on-off valve 22c, and closes the second inlet side on-off valve 22d.

[0377] For this reason, in the heat pump cycle 10a in the single hot gas heating mode, the refrigerant discharged from the compressor 11 circulates in the following order: the first three-way joint 12a, the indoor condenser 13, the receiver 24, the cooling expansion valve 14c in the throttled state, the chiller 20, the sixth three-way joint 12f, and the suction port 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 the following order: the first three-way joint 12a, the bypass-side flow control valve 14d in the throttled state arranged in the bypass passage 21c, the sixth three-way joint 12f, and the suction port of the compressor 11.

[0378] Furthermore, the control device 60 changes the throttle opening of the cooling expansion valve 14c so that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH. The control device 60 also appropriately controls the operation of other controlled devices, as in the single hot gas heating mode of the first embodiment. In the hot gas heating mode of this embodiment, the upper limit opening control is also executed, as in the first embodiment.

[0379] Therefore, in the hot gas heating mode, the cooling expansion valve 14c serves as the heating section side pressure reducing section, and the sixth three-way joint 12f serves as the mixing section, as in the first embodiment. Also, in the hot gas heating mode, the operation of at least one of the compressor 11, the cooling expansion valve 14c, and the bypass side flow control valve 14d is controlled so that the blowing air temperature TAV approaches the target blowing temperature TAO and the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH.

[0380] As a result, in the single hot gas heating mode of this embodiment, as in the first embodiment, even if the outside air temperature Tam is extremely low, the heat generated by the work of the compressor 11 is effectively used to heat the blown air, thereby realizing heating of the vehicle cabin. Furthermore, by executing the upper limit opening control, the compressor 11 can be protected.

[0381] (d-2) Cooling hot gas heating mode In the cooled hot gas heating mode, the controller 60 operates the low-temperature side pump 41 so as to exert a predetermined reference pumping capacity in contrast to the single hot gas heating mode. Other operations are the same as those in the single hot gas heating mode.

[0382] Therefore, in the cooling hot gas heating mode, the heat generated by the work of the compressor 11 is effectively used to heat the blown air, thereby heating the vehicle cabin. Also, like the cooling hot gas heating mode of the first embodiment, the battery 70 can be cooled. Furthermore, the upper limit opening control is executed, thereby protecting the compressor 11.

[0383] (d-3) Warm-up hot gas heating mode In the warm-up hot gas heating mode, the controller 60 operates the low-temperature side pump 41 so as to exert a predetermined reference pumping capacity in contrast to the single hot gas heating mode. Other operations are the same as those in the single hot gas heating mode.

[0384] Therefore, in the warm-up hot gas heating mode, the heat generated by the work of the compressor 11 is effectively used to heat the blown air, thereby heating the vehicle cabin. Furthermore, like the warm-up hot gas heating mode of the first embodiment, the battery 70 can be warmed up. Furthermore, the upper limit opening control is executed, thereby protecting the compressor 11.

[0385] (e-1) Single hot gas dehumidification heating mode In the heat pump cycle 10a in the single hot gas dehumidification heating mode, the controller 60 fully closes the heating expansion valve 14a, throttles the cooling expansion valve 14b, throttles the cooling expansion valve 14c, and throttles the bypass-side flow control valve 14d. The controller 60 also closes the heating on-off valve 22b, opens the first inlet on-off valve 22c, and closes the second inlet on-off valve 22d.

[0386] Therefore, in the heat pump cycle 10a in the single hot gas dehumidification heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the hot gas heating mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates through the first three-way joint 12a, the indoor condenser 13, the receiver 24, the cooling expansion valve 14b in the throttling state, the indoor evaporator 18, and the suction port of the compressor 11 in this order.

[0387] Furthermore, the control device 60 changes the throttle opening of the cooling expansion valve 14c so that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH. The control device 60 also appropriately controls the operation of other controlled devices, as in the single hot gas dehumidification heating mode of the first embodiment. In the hot gas dehumidification heating mode of this embodiment, the upper limit opening control and the opening increase control are also executed, as in the first embodiment.

[0388] Therefore, in the hot gas dehumidifying and heating mode, the cooling expansion valve 14c serves as a heating section side pressure reducing section, and the sixth three-way joint 12f serves as a mixing section, as in the first embodiment. Furthermore, the tenth three-way joint 12j serves as an auxiliary branch section, the cooling expansion valve 14b serves as an auxiliary heating section side pressure reducing section, and the indoor evaporator 18 serves as an evaporation section.

[0389] In addition, in the hot gas dehumidification heating mode, the operation of at least one of the compressor 11, the cooling expansion valve 14c, and the bypass side flow control valve 14d is controlled so that the blowing air temperature TAV approaches the target blowing temperature TAO and the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH.

[0390] As a result, in the single hot gas dehumidifying and heating mode of this embodiment, the ventilation air can be heated with a heating capacity higher than that of the series dehumidifying and heating mode, and dehumidifying and heating the vehicle interior can be realized, as in the first embodiment. Furthermore, the upper limit opening control and the opening increase control are executed, so that the compressor 11 can be protected.

[0391] (e-2) Cooling hot gas dehumidification heating mode In the cooling hot gas dehumidification heating mode, the controller 60 operates the low-temperature side pump 41 so as to exert a predetermined reference pumping capacity in comparison with the single hot gas dehumidification heating mode. The other operations are the same as those in the single hot gas dehumidification heating mode.

[0392] Therefore, in the cooling hot gas dehumidifying heating mode, like the single hot gas dehumidifying heating mode, the blown air can be heated with a heating capacity higher than that in the series dehumidifying heating mode, thereby realizing dehumidifying and heating of the vehicle interior. Also, like the cooling hot gas dehumidifying heating mode of the first embodiment, the battery 70 can be cooled. Furthermore, the upper limit opening control and the opening increase control are executed, thereby protecting the compressor 11.

[0393] (f-1) Single hot gas series dehumidification heating mode In the heat pump cycle 10a in the single hot gas series dehumidification heating mode, the controller 60 throttles the heating expansion valve 14a, throttles the cooling expansion valve 14b, throttles the cooling expansion valve 14c, and throttles the bypass side flow control valve 14d. The controller 60 also closes the heating on-off valve 22b, closes the first inlet side on-off valve 22c, and opens the second inlet side on-off valve 22d.

[0394] Therefore, in the heat pump cycle 10a in the single hot gas series dehumidification heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the cooling series dehumidification heating mode. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which it circulates through the first three-way joint 12a, the bypass-side flow control valve 14d in the throttling state arranged in the bypass passage 21c, the sixth three-way joint 12f, and the suction port of the compressor 11 in that order.

[0395] Furthermore, the control device 60 changes the throttle opening of the cooling expansion valve 14c so that the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH. The control device 60 also appropriately controls the operation of other controlled devices, as in the single hot gas series dehumidification heating mode of the first embodiment. In the hot gas series dehumidification heating mode of this embodiment, the upper limit opening control and the opening increase control are also executed, as in the first embodiment.

[0396] Therefore, in the hot gas serial dehumidification heating mode, the heating expansion valve 14a and the cooling expansion valve 14c function as the heating section side pressure reducing section, and the sixth three-way joint 12f functions as the mixing section, as in the first embodiment. Furthermore, the tenth three-way joint 12j functions as the auxiliary branch section, the cooling expansion valve 14b functions as the auxiliary heating section side pressure reducing section, and the indoor evaporator 18 functions as the evaporation section.

[0397] In addition, in the hot gas series dehumidification heating mode, the operation of at least one of the compressor 11, the cooling expansion valve 14c, and the bypass side flow control valve 14d is controlled so that the blowing air temperature TAV approaches the target blowing temperature TAO and the superheat degree SH of the suction refrigerant approaches the reference superheat degree KSH.

[0398] As a result, in the single hot gas series dehumidifying and heating mode of this embodiment, the blown air can be heated with a heating capacity higher than that of the series dehumidifying and heating mode, and dehumidifying and heating the vehicle interior can be realized, as in the first embodiment. Furthermore, the upper limit opening control and the opening increase control are executed, so that the compressor 11 can be protected.

[0399] (f-2) Cooling hot gas serial dehumidification heating mode In the cooling hot gas series dehumidification heating mode, the controller 60 operates the low-temperature side pump 41 so as to exert a predetermined reference pumping capacity in comparison with the single hot gas series dehumidification heating mode. The other operations are the same as those in the single hot gas series dehumidification heating mode.

[0400] Therefore, in the cooling hot gas series dehumidification heating mode, like the single hot gas series dehumidification heating mode, the blown air is heated with a heating capacity higher than that of the series dehumidification heating mode, and dehumidification and heating of the vehicle interior can be realized. Also, like the cooling hot gas series dehumidification heating mode of the first embodiment, the battery 70 can be cooled. Furthermore, the upper limit opening control and the opening increase control are executed, so that the compressor 11 can be protected.

[0401] As described above, the vehicle air conditioner 1a of this embodiment can also provide the same effects as those of the first embodiment. That is, by switching the operation mode, it is possible to provide comfortable air conditioning for the vehicle interior and appropriate temperature adjustment for the battery 70, which is an on-board device. At this time, even if refrigerants with different enthalpies are mixed and sucked into the compressor 11, the state of the sucked refrigerant can be maintained in an appropriate state, and the compressor 11 can be reliably protected.

[0402] Furthermore, since the heat pump cycle 10a of the present embodiment includes the receiver 24, the high-pressure side liquid phase refrigerant can be stored in the receiver 24 as surplus refrigerant of the cycle.

[0403] This allows the refrigerant at the outlet side of the heat exchanger functioning as an evaporator to have a degree of superheat. Therefore, it is possible to increase the enthalpy difference obtained by subtracting the enthalpy of the refrigerant at the inlet side from the enthalpy of the refrigerant at the outlet side of the heat exchanger functioning as an evaporator. As a result, in the heat pump cycle 10a, the amount of heat absorption by the refrigerant in the heat exchanger functioning as an evaporator can be increased, thereby improving the COP.

[0404] Of course, in the vehicle air conditioning device 1 of this embodiment, even if the operation of at least one of the compressor 11, the heating section side pressure reduction section, and the bypass side flow control valve 14d is controlled so that the blowing air temperature TAV approaches the target blowing temperature TAO and the dryness Rx of the intake refrigerant approaches the reference dryness KRx, the compressor 11 can be reliably protected, as in the first embodiment.

[0405] The present disclosure is not limited to the above-described embodiment, and various modifications can be made as follows without departing from the spirit and scope of the present disclosure.

[0406] In the above embodiment, an example in which the heat pump cycle device according to the present disclosure is applied to an air conditioner has been described, but the application of the heat pump cycle device is not limited to air conditioners. For example, the heat pump cycle device may be applied to a hot water supply device that heats water for daily use as an object to be heated. In addition, the object to be heated is not limited to a fluid. For example, the heat pump cycle device may be a heat generating device in which a heat medium passage is formed through which a high-temperature heat medium flows for warming up or the like.

[0407] The configuration of the heat pump cycle device according to the present disclosure is not limited to the configurations disclosed in the above-described embodiments.

[0408] In the above embodiment, an example in which the indoor condenser 13 is used as the heating section has been described, but the heating section is not limited to the indoor condenser 13. For example, the heating section may be one in which a high-temperature side pump, a water-refrigerant heat exchanger, a heater core, and the like are arranged in a high-temperature side heat medium circulation circuit that circulates the high-temperature side heat medium.

[0409] The high-temperature side pump is a pump that pumps the high-temperature side heat medium into the water passage of the water-refrigerant heat exchanger. The high-temperature side heat medium can be the same type of fluid as the low-temperature side heat medium. The water-refrigerant heat exchanger is a heat exchanger that exchanges heat between the high-pressure refrigerant discharged from the compressor 11 and the high-temperature side heat medium pumped from the high-temperature side pump. The heater core is a heating heat exchanger that exchanges heat between the high-temperature side heat medium heated in the water-refrigerant heat exchanger and the blown air.

[0410] The heater core is disposed in the air passage of the indoor air conditioning unit 50 similarly to the indoor condenser 13. With this, in the hot gas heating mode or the like, the discharged refrigerant can be used as a heat source to indirectly heat the blown air, which is the object to be heated, via the high-temperature side heat medium.

[0411] In the above-described embodiment, an example was described in which the sixth three-way joint 12f as a mixing section is arranged in the refrigerant path from the refrigerant outlet of the chiller 20 to the other inlet of the fifth three-way joint 12e, but the arrangement of the sixth three-way joint 12f is not limited to this.

[0412] For example, the sixth three-way joint 12f may be disposed in a refrigerant path extending from the outlet of the cooling expansion valve 14c to the refrigerant inlet of the chiller 20, or in a refrigerant path extending from the outlet of the fifth three-way joint 12e to the other inlet of the fourth three-way joint 12d. Alternatively, the sixth three-way joint 12f may be disposed in a refrigerant path extending from the outlet of the fourth three-way joint 12d to the inlet of the accumulator 23.

[0413] In the above embodiment, an example in which the second check valve 16b is used has been described, but an evaporation pressure regulating valve may be used instead of the second check valve 16b. The evaporation pressure regulating valve is a variable throttle mechanism that maintains the refrigerant evaporation temperature in the indoor evaporator 18 at a predetermined temperature or higher (for example, a temperature at which the indoor evaporator 18 can be suppressed).

[0414] The evaporation pressure regulating valve may be a variable throttle mechanism formed of a mechanical mechanism that increases the valve opening in response to an increase in the refrigerant pressure on the refrigerant outlet side of the indoor evaporator 18. Alternatively, the evaporation pressure regulating valve may be a variable throttle mechanism formed of an electrical mechanism similar to that of the heating expansion valve 14a, etc.

[0415] The heat pump cycle 10a of the fourth embodiment described above may be provided with a subcooling expansion valve for reducing the pressure of the refrigerant flowing into the receiver 24. More specifically, the subcooling expansion valve may be a fixed throttle or a variable throttle mechanism. The subcooling expansion valve is desirably provided in the refrigerant path extending from the outlet of the seventh three-way joint 12g to the inlet of the receiver 24.

[0416] This makes it possible to increase the degree of subcooling of the refrigerant flowing out from the indoor condenser 13, thereby increasing the refrigerant pressure in the indoor condenser 13 (i.e., the discharge refrigerant pressure Pd). As a result, the heating capacity of the indoor condenser 13 for heating the blown air can be improved.

[0417] In addition, 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 embodiment. Various detection units may be added as necessary. For example, a dryness sensor capable of directly detecting the intake refrigerant may be added.

[0418] In the above embodiment, the refrigerant of the heat pump cycle 10, 10a is R1234yf, but the present invention is not limited thereto. For example, R134a, R600a, R410A, R404A, R32, R407C, etc. may be used. Alternatively, a mixed refrigerant of a mixture of a plurality of these refrigerants may be used. Furthermore, a supercritical refrigeration cycle may be configured in which carbon dioxide is used as the refrigerant and the high-pressure side refrigerant pressure is equal to or higher than the critical pressure of the refrigerant.

[0419] In addition, although an example in which an ethylene glycol aqueous solution is used as the low-temperature side heat medium and the high-temperature side heat medium in the above-mentioned embodiment has been described, the present invention is not limited to this. For example, dimethylpolysiloxane, a solution containing nanofluid, antifreeze, a water-based liquid refrigerant containing alcohol, a liquid medium containing oil, etc. may be used as the high-temperature side heat medium and the low-temperature side heat medium.

[0420] The control aspects of the heat pump cycle apparatus according to the present disclosure are not limited to the control aspects disclosed in the above-described embodiments.

[0421] In the above embodiment, the vehicle air conditioner 1 capable of executing various operation modes has been described, but it is not necessary that all of the above operation modes can be executed. As long as at least one of the hot gas heating mode, the hot gas defrost heating mode, and the hot gas serial dehumidification heating mode can be executed, the compressor can be reliably protected even if refrigerants with different enthalpies are mixed and sucked into the compressor.

[0422] In the above embodiment, an example in which step S12 is adopted as the adjustment capacity determination unit has been described, but the adjustment capacity determination unit is not limited to this. For example, step S12 may be eliminated, and a control process may be added to the control map of step S13 in which the upper limit opening is not set when the control zone is zone 0. That is, if it is possible to determine that the flow rate adjustment capacity of either the heating unit side pressure reducing unit or the bypass side flow rate adjustment valve 14d is equal to or lower than the reference adjustment capacity, it is included in the adjustment capacity determination unit.

[0423] In the above embodiment, the upper limit opening degree is changed in accordance with the change in the throttle opening degree of one of the heating unit side pressure reducing unit and the bypass side flow rate adjustment valve 14d and the change in the valve differential pressure ratio. However, the present invention is not limited to this. For example, the upper limit opening degree may be a predetermined fixed value.

[0424] In the above embodiment, the (d) hot gas heating mode, which is executed when the outside air temperature Tam is extremely low, is executed in the (d-3) warm-up hot gas heating mode, which warms up the battery 70. However, the present invention is not limited to this. An operation mode for warming up the battery 70 may be added to other operation modes.

[0425] In the above-described second embodiment, the control zone for the upper limit opening control is determined using the valve differential pressure ratio, but the present invention is not limited to this. For example, the control zone may be determined using the smaller of the heating unit side differential pressure and the bypass side differential pressure.

[0426] Then, when the smaller upstream-to-downstream differential pressure is greater than a predetermined reference upstream-to-downstream differential pressure, the control zone may be determined to be zone 0. Furthermore, when the smaller upstream-to-downstream differential pressure is equal to or greater than the reference upstream-to-downstream differential pressure, the control zones may be determined in the order of zone 1, zone 2, and zone 3 as the smaller upstream-to-downstream differential pressure decreases.

[0427] In the hot gas heating modes of the first, second and fourth embodiments described above, the refrigerant discharge capacity of the compressor 11 is controlled so that the suction refrigerant pressure Ps approaches the predetermined first target low pressure PSO1. Furthermore, an example has been described in which the operation of the bypass-side flow control valve 14d is controlled so that the discharge refrigerant pressure Pd approaches the target high pressure PDO, but this is not limiting.

[0428] For example, the control device 60 may control the refrigerant discharge capacity of the compressor 11 so that the discharge refrigerant pressure Pd approaches the target high pressure PDO. In this case, the control device 60 may control the operation of the bypass side flow rate control valve 14d so that the suction refrigerant pressure Ps approaches the first target low pressure PSO1. Furthermore, the control device 60 may control the operation of the cooling expansion valve 14c so that the subcooling degree SC1 approaches the first target subcooling degree SCO1.

[0429] For example, the control device 60 may control the refrigerant discharge capacity of the compressor 11 so that the discharge refrigerant pressure Pd approaches the target high pressure PDO. In this case, the control device 60 may control the refrigerant discharge capacity of the compressor 11 so that the suction refrigerant pressure Ps approaches the first target low pressure PSO1. Furthermore, the control device 60 may control the operation of the bypass side flow rate control valve 14d so that the subcooling degree SC1 approaches the first target subcooling degree SCO1.

[0430] In other words, in the hot gas heating mode, the effect of the above-mentioned upper limit opening control can be obtained by controlling the operation of at least one of the compressor 11, the cooling expansion valve 14c, and the bypass side flow control valve 14d so that the blowing air temperature TAV approaches the target blowing temperature TAO and the dryness Rx of the intake refrigerant approaches the reference dryness KRx.

[0431] Similarly, in the hot gas heating mode, the effect of the above-mentioned upper limit opening control can be obtained by controlling the operation of at least one of the compressor 11, the cooling expansion valve 14c, and the bypass side flow control valve 14d so that the blowing air temperature TAV approaches the target blowing temperature TAO and the superheat degree SH of the intake refrigerant approaches a predetermined reference superheat degree KSH.

[0432] This also applies to the hot gas dehumidification heating mode and the hot gas serial dehumidification heating mode.

[0433] The means disclosed in each of the above-mentioned embodiments may be appropriately combined within a feasible range. For example, in the vehicle air conditioner 1a of the fourth embodiment, the control zone for the upper limit opening control may be determined using the valve differential pressure ratio, as in the second embodiment. For example, in the vehicle air conditioner 1a of the fourth embodiment, the operation of the heating unit side pressure reducing unit and the bypass side flow rate adjusting unit may be controlled using the opening ratio, as in the third embodiment.

[0434] Although the present disclosure has been described based on the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, and other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and concept of the present disclosure.

Claims

1. A compressor (11) that compresses and discharges a refrigerant; A branching portion (12a) for branching a flow of a discharged refrigerant discharged from the compressor; a heating section (13) that heats an object to be heated using one of the discharged refrigerants branched at the branch section as a heat source; a heating unit side pressure reducing section (14c) for reducing the pressure of the refrigerant flowing out from the heating unit; a bypass passage (21c) for guiding the other of the discharged refrigerant branched at the branch portion to a suction port side of the compressor; a bypass-side flow rate adjusting unit (14d) for adjusting a flow rate of the refrigerant flowing through the bypass passage; a mixing section (12f) that mixes the refrigerant flowing out from the bypass side flow rate adjustment section and the refrigerant flowing out from the heating section side pressure reduction section and flows the refrigerant toward a suction port side of the compressor; A target temperature determination unit (S3) that determines a target temperature (TAO) that is a target value of an object temperature (TAV) of the object heated by the heating unit; and an adjustment capability determination unit (S12) that determines whether the flow rate adjustment capability of one of the heating unit side pressure reduction unit and the bypass side flow rate adjustment unit is equal to or less than a predetermined reference adjustment capability, control operation of at least one of the heating unit side pressure reducing unit and the bypass side flow rate adjusting unit so that the object temperature (TAV) approaches the target temperature (TAO) and the dryness (Rx) of the suction refrigerant suctioned into the compressor approaches a predetermined reference dryness (KRx), or so that the object temperature (TAV) approaches the target temperature (TAO) and the superheat (SH) of the suction refrigerant approaches a predetermined reference superheat (KSH); When the adjustment capacity determination unit determines that the flow rate adjustment capacity of one of the heating unit side pressure reduction unit and the bypass side flow rate adjustment unit is equal to or lower than the reference adjustment capacity, the heat pump cycle device reduces the throttle opening of the other of the heating unit side pressure reduction unit and the bypass side flow rate adjustment unit.

2. The heat pump cycle apparatus according to claim 1, wherein the adjustment capacity determination unit determines that the flow rate adjustment capacity of one of the heating unit side pressure reduction unit and the bypass side flow rate adjustment unit is equal to or lower than the standard adjustment capacity when the throttle opening of one of the heating unit side pressure reduction unit and the bypass side flow rate adjustment unit is equal to or higher than a predetermined standard limit opening.

3. and an upper limit opening degree determining unit (S13) that determines an amount of reduction in the throttle opening degree of the other of the heating unit side pressure reducing unit and the bypass side flow rate adjusting unit when the flow rate adjusting capacity determining unit determines that the flow rate adjusting capacity of one of the heating unit side pressure reducing unit and the bypass side flow rate adjusting unit is equal to or lower than the reference adjustment capacity, The heat pump cycle apparatus according to claim 2 , wherein the upper limit opening degree determining unit increases the amount of decrease as the throttle opening degree of one of the heating unit-side pressure reducing unit and the bypass-side flow rate adjusting unit increases.

4. The upstream-to-downstream differential pressure of the heating unit-side pressure reducing section is defined as the upstream-to-downstream differential pressure of the heating unit-side pressure reducing section, A differential pressure between the upstream and downstream of the bypass side flow rate adjustment unit is defined as a differential pressure between the upstream and downstream of the bypass side flow rate adjustment unit, When the ratio of the smaller of the heating section side differential pressure and the bypass side differential pressure to the larger of the smaller differential pressure is defined as a valve differential pressure ratio, one of the heating unit-side pressure reduction unit and the bypass-side flow rate adjustment unit is a unit that has a smaller value of the heating unit-side front-to-back pressure difference and the bypass-side front-to-back pressure difference, The heat pump cycle apparatus of claim 1, wherein the adjustment capacity determination unit determines that the flow rate adjustment capacity of one of the heating unit side pressure reduction unit and the bypass side flow rate adjustment unit is equal to or lower than the standard adjustment capacity when the valve differential pressure ratio is equal to or lower than a predetermined standard valve differential pressure ratio.

5. and an upper limit opening degree determining unit (S13) that determines an amount of reduction in the throttle opening degree of the other of the heating unit side pressure reducing unit and the bypass side flow rate adjusting unit when the flow rate adjusting capacity determining unit determines that the flow rate adjusting capacity of one of the heating unit side pressure reducing unit and the bypass side flow rate adjusting unit is equal to or lower than the reference adjustment capacity, The heat pump cycle apparatus according to claim 4 , wherein the upper limit opening determination unit increases the amount of decrease as the valve differential pressure ratio decreases.

6. A compressor (11) that compresses and discharges a refrigerant; A branching portion (12a) for branching a flow of a discharged refrigerant discharged from the compressor; a heating section (13) that heats an object to be heated using one of the discharged refrigerants branched at the branch section as a heat source; a heating unit side pressure reducing section (14c) for reducing the pressure of the refrigerant flowing out from the heating unit; a bypass passage (21c) for guiding the other of the discharged refrigerant branched at the branch portion to a suction port side of the compressor; a bypass-side flow rate adjusting unit (14d) for adjusting a flow rate of the refrigerant flowing through the bypass passage; a mixing section (12f) that mixes the refrigerant flowing out from the bypass-side flow rate adjustment section and the refrigerant flowing out from the heating section-side pressure reduction section and causes the refrigerant to flow out to a suction port side of the compressor, A heat pump cycle device in which an opening ratio of the throttle opening of the heating section side pressure reduction section to the throttle opening of the bypass side flow rate adjustment section is adjusted so that the dryness (Rx) of the suctioned refrigerant suctioned into the compressor approaches a predetermined reference dryness (KRx) or so that the superheat (SH) of the suctioned refrigerant approaches a predetermined reference superheat (KSH).

7. an auxiliary branching portion (12x, 12j) that branches the flow of the refrigerant flowing out from the heating portion; an auxiliary heating section side pressure reducing section (14b) for reducing the pressure of one of the refrigerants branched at the auxiliary branch section; an evaporation section (18) that evaporates the refrigerant decompressed by the auxiliary heating section side decompression section and causes it to flow to a suction port side of the compressor, 7. A heat pump cycle device as described in any one of claims 1 to 6, wherein when the refrigerant is flowing into the evaporation section (18) and the throttle opening of the heating section side pressure reduction section is equal to or greater than a predetermined reference increased opening, the throttle opening of the auxiliary heating section side pressure reduction section is prohibited from being reduced.

Images