Heat pump cycle device

Abstract

This heat pump cycle apparatus comprises: a compressor (11); an upstream-side branching part (12a); a heating unit (13); an outside air heat exchanging unit (15); an upstream-side decompression unit (14a); a downstream-side decompression unit (14c); a bypass passage (21a); and a bypass-side flow rate adjustment unit (14d). During a heating mode in which a to-be-heated object is heated, a portion of coolant that has been decompressed by the upstream-side decompression unit (14a) is caused to flow into the outside air heat exchanging unit (15), and the portion of coolant in the outside air heat exchanging unit (15) is caused to absorb the heat of outside air. During a defrosting mode in which frost is removed from the outside air heat exchanging unit (15), one portion of coolant that has branched off at the upstream-side branching part (12a) is caused to flow into the outside air heat exchanging unit (15) and to dissipate heat; said portion of coolant is then decompressed by the downstream-side decompression unit (14c) and mixed with a portion of coolant flowing out from the bypass-side flow rate adjustment unit (14d); and the resulting mixture is sucked into the compressor (11).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2022-101833 filed on June 24, 2022, the contents of which are incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to a heat pump cycle apparatus capable of operating in a defrosting mode to remove frost that has formed on an outdoor air heat exchanger. [Background technology]

[0003] Patent Document 1 discloses a heat pump cycle device that can operate in a defrosting mode to remove frost that forms on an outdoor air heat exchanger that exchanges heat between a refrigerant and outdoor air. The heat pump cycle device of Patent Document 1 performs so-called condensation heat defrosting, in which high-temperature refrigerant discharged from a compressor flows into the outdoor air heat exchanger to melt and remove the frost that forms on the outdoor air heat exchanger.

[0004] Furthermore, in the heat pump cycle device of Patent Document 1, in order to quickly complete defrosting of the outdoor air heat exchanger, it is possible to switch to an endothermic defrosting mode in which waste heat from heat-generating devices that generate heat during operation and heat generated by an electric heater are used for defrosting in addition to the compression work of the compressor. In the endothermic defrosting mode, the heat generated by heat absorption sources such as heat-generating devices and electric heaters is absorbed by the low-pressure side refrigerant and used as defrosting heat for defrosting the outdoor air heat exchanger. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-133795 Summary of the Invention

[0006] However, in the heat pump cycle device of Patent Document 1, if the heat absorption source cannot generate sufficient heat for defrosting, it may not be possible to quickly complete defrosting of the outdoor air heat exchange section.

[0007] In view of the above, an object of the present disclosure is to provide a heat pump cycle apparatus that can quickly complete defrosting of an outdoor air heat exchanger.

[0008] A heat pump cycle device according to one aspect of the present disclosure includes a compressor, an upstream branch section, a heating section, an outdoor air heat exchange section, an upstream pressure reduction section, a downstream pressure reduction section, a bypass passage, and a bypass flow rate adjustment section.

[0009] The compressor compresses and discharges the refrigerant. The upstream branching section branches the flow of the refrigerant discharged from the compressor. The heating section heats an object to be heated using the refrigerant flowing out from one outlet of the upstream branching section as a heat source. The outside air heat exchange section exchanges heat between the refrigerant and outside air. The upstream pressure reduction section reduces the pressure of the refrigerant flowing into the outside air heat exchange section. The downstream pressure reduction section reduces the pressure of the refrigerant flowing out from the outside air heat exchange section. The bypass passage is a refrigerant passage that guides the refrigerant flowing out from the other outlet of the upstream 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.

[0010] In a heating mode in which the heating section heats an object to be heated, the refrigerant decompressed in the upstream decompression section flows into the outside air heat exchange section, where the refrigerant absorbs heat from the outside air.

[0011] In addition, in the defrosting mode for removing frost that has accumulated in the outdoor air heat exchange section, the refrigerant flowing out from one outlet of the upstream branch section flows into the outdoor air heat exchange section to dissipate heat, the refrigerant flowing out from the outdoor air heat exchange section is depressurized in the downstream pressure reduction section, and the refrigerant depressurized in the downstream pressure reduction section is mixed with the refrigerant flowing out from the bypass side flow rate adjustment section and is then drawn into the compressor.

[0012] According to this, even if frost forms on the outdoor air heat exchanger when the heating mode is performed, the outdoor air heat exchanger can be defrosted by performing the defrosting mode operation.

[0013] Furthermore, in the defrost mode, the refrigerant decompressed by the downstream pressure reducing section and the refrigerant flowing out from the bypass side flow rate adjusting section are mixed and drawn into the compressor. That is, in the defrost mode, the refrigerant decompressed by the downstream pressure reducing section is mixed with the refrigerant with a relatively high enthalpy, thereby balancing the cycle.

[0014] This allows the refrigerant at the outlet of the outdoor air heat exchanger to have a relatively low enthalpy, increasing the amount of heat dissipated by the refrigerant in the outdoor air heat exchanger, thereby increasing the amount of heat dissipated from the refrigerant to the frost on the outdoor air heat exchanger and quickly completing defrosting of the outdoor air heat exchanger. [Brief explanation of the drawings]

[0015] 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 diagram illustrating the overall configuration of an air conditioning system for a vehicle according to an embodiment of the present invention; [Figure 2] 1 is a schematic configuration diagram of an indoor air conditioning unit according to an embodiment; [Figure 3] 2 is a block diagram showing an electrical control unit of the vehicle air conditioner according to the embodiment; FIG. [Figure 4] 10 is a flowchart of a subroutine of a control program according to an embodiment. [Figure 5] 1 is a schematic overall configuration diagram illustrating a refrigerant flow and the like in an endothermic defrosting mode of a heat pump cycle according to an embodiment. FIG. [Figure 6] 1 is a schematic overall configuration diagram showing a refrigerant flow and the like in an endothermic hot gas defrosting mode of a heat pump cycle of an embodiment. FIG. [Figure 7] FIG. 2 is a Mollier diagram showing the state of the refrigerant in a single endothermic hot gas defrosting mode of the heat pump cycle of the embodiment. [Figure 8] FIG. 2 is a Mollier diagram showing the state of a refrigerant in a heating heat absorption hot gas defrosting mode of a heat pump cycle according to an embodiment. [Figure 9] 1 is a schematic overall configuration diagram showing a refrigerant flow and the like in a hot gas defrosting mode of a heat pump cycle of an embodiment. FIG. [Figure 10] FIG. 2 is a Mollier diagram showing the state of a refrigerant in a single hot gas defrosting mode of a heat pump cycle according to an embodiment. [Figure 11] FIG. 2 is a Mollier diagram showing the state of a refrigerant in a heating hot gas defrosting mode of a heat pump cycle according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of a heat pump cycle device according to the present disclosure will be described with reference to FIGS. 1 to 11. 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 power for traveling from an electric motor. The vehicle air conditioner 1 conditions the air inside the vehicle cabin, which is the space to be air-conditioned, and also adjusts the temperature of on-board equipment. Therefore, the vehicle air conditioner 1 can be called an air conditioner with an on-board equipment temperature adjustment function, or an on-board equipment temperature adjustment device with an air conditioning function.

[0017] Specifically, the vehicle air conditioner 1 adjusts the temperature of a battery 70 as an in-vehicle device. The battery 70 is a secondary battery that stores power to be supplied to a plurality of electrically operated in-vehicle devices. The battery 70 is an assembled battery formed by electrically connecting a plurality of stacked battery cells in series or parallel. The battery cells in this embodiment are lithium-ion batteries.

[0018] The battery 70 is a heat-generating device that generates heat during operation (i.e., during charging and discharging). The output of the battery 70 is likely to decrease at low temperatures, and deterioration is likely to progress at high temperatures. For this reason, the temperature of the battery 70 needs to be maintained within an appropriate temperature range (in this embodiment, 15°C or higher and 55°C or lower). Therefore, in the electric vehicle of this embodiment, the temperature of the battery 70 is adjusted using the vehicle air conditioner 1.

[0019] Furthermore, in the vehicle air conditioner 1, when frost forms on the outside-air heat exchanger 15 of the heat pump cycle 10 (described later), the heat generated by the battery 70 can be used as a heat source for melting and removing the frost on the outside-air heat exchanger 15. Therefore, the battery 70 serves as a heat absorption source that generates defrosting heat used to defrost the outside-air heat exchanger 15.

[0020] The vehicle air conditioner 1 is configured to be able to switch operating modes in order to air-condition the vehicle interior and adjust the temperature of the battery 70. The vehicle air conditioner 1 includes a heat pump cycle 10, a low-temperature side heat medium circuit 40, an interior air conditioning unit 50, a control device 60, etc.

[0021] First, a heat pump cycle 10 will be described with reference to Fig. 1. The heat pump cycle 10 is a vapor compression refrigeration cycle that adjusts the temperature of the air blown into the vehicle cabin and the low-temperature side heat medium circulating through a low-temperature side heat medium circuit 40. The heat pump cycle 10 is configured to be able to switch the circuit configuration of the refrigerant circuit depending on the operation mode of the vehicle air conditioner 1 in order to condition the air in the vehicle cabin and adjust the temperature of on-board equipment.

[0022] The heat pump cycle 10 uses an HFO refrigerant (specifically, R1234yf) as a refrigerant. The heat pump cycle 10 constitutes a subcritical refrigeration cycle in which the pressure of the high-pressure side refrigerant does not exceed the critical pressure of the refrigerant. Refrigerant oil is mixed with the refrigerant to lubricate the compressor 11. The refrigerant oil is PAG oil that is compatible with liquid-phase refrigerants. A portion of the refrigerant oil circulates through the heat pump cycle 10 together with the refrigerant.

[0023] The compressor 11 draws in, compresses, and discharges refrigerant in the heat pump cycle 10. The compressor 11 is an electric compressor that uses an electric motor to rotate a fixed-displacement compression mechanism with a fixed discharge capacity. The rotation speed (i.e., refrigerant discharge capacity) of the compressor 11 is controlled by a control signal output from a control device 60, which will be described later.

[0024] The compressor 11 is disposed in a drive unit compartment formed at the front side of the vehicle interior. The drive unit compartment forms a space in which at least some of the devices used to generate and adjust the driving force for running the vehicle (for example, an electric motor for running) are disposed.

[0025] 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 inlet and outlet ports that communicate with each other. The first three-way joint 12a can be a joint formed by joining multiple pipes or a joint formed by providing multiple refrigerant passages in a metal block or a resin block.

[0026] Furthermore, as will be described later, the heat pump cycle 10 includes a second three-way joint 12b to a sixth three-way joint 12f. 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.

[0027] These three-way joints function as a branching section where the refrigerant flow branches when one of the three inlet / outlet ports is used as an inlet and the other two are used as outlet ports, and as a merging section where the refrigerant flow merges when two of the three inlet / outlet ports are used as inlet ports and the other is used as an outlet port.

[0028] For example, the first three-way joint 12a serves as an upstream branching part that branches the flow of refrigerant discharged from the compressor 11. The sixth three-way joint 12f serves as a bypass-side merging part that merges the flow of refrigerant flowing out from a cooling expansion valve 14c (described later) and the flow of refrigerant flowing out from a bypass-side flow control valve 14d (described later).

[0029] One outlet of the first three-way joint 12a is connected to the refrigerant inlet side of the indoor condenser 13. The other outlet of the first three-way joint 12a is connected to one inlet side of a sixth three-way joint 12f. The refrigerant passage extending from the other outlet of the first three-way joint 12a to one inlet of the sixth three-way joint 12f is a bypass passage 21a. A bypass-side flow control valve 14d is disposed in the bypass passage 21a.

[0030] The bypass-side flow rate adjustment valve 14d is a bypass-side pressure reduction unit that reduces the pressure of the refrigerant flowing out from the other outlet of the first three-way joint 12a (i.e., the other refrigerant branched at the first three-way joint 12a) in a hot gas heating mode, etc., which will be described later. The bypass-side flow rate adjustment valve 14d is also a bypass-side flow rate adjustment unit that adjusts the mass flow rate of the refrigerant flowing through the bypass passage 21a.

[0031] The bypass-side flow rate adjustment valve 14d is an electric variable throttle mechanism having a valve element that changes the throttle opening and an electric actuator that displaces the valve element. A stepping motor or a brushless motor can be used as the electric actuator. The operation of the bypass-side flow rate adjustment valve 14d is controlled by a control signal output from the control device 60.

[0032] The bypass-side flow control valve 14d has a full-open function that functions simply as a refrigerant passage by fully opening the valve and exerts almost no refrigerant pressure reduction or flow rate adjustment action, and a full-close function that closes the refrigerant passage by fully closing the valve.

[0033] Furthermore, as will be described later, 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.

[0034] The heating expansion valve 14a, the cooling expansion valve 14b, the cooling expansion valve 14c, and the bypass-side flow rate adjustment valve 14d can switch the refrigerant circuit by using the fully closing function described above. Therefore, the heating expansion valve 14a, the cooling expansion valve 14b, the cooling expansion valve 14c, and the bypass-side flow rate adjustment valve 14d function as an operation mode switching unit that switches the operation mode by switching the refrigerant circuit.

[0035] Of course, the heating expansion valve 14a, the cooling expansion valve 14b, the cooling expansion valve 14c, and the bypass-side flow 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 an operation mode switching unit.

[0036] 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 branches at the first three-way joint 12a) and the blown air that has passed through an indoor evaporator 18, which will be described later.

[0037] The indoor condenser 13 heats the blown air by radiating heat from the discharged refrigerant to the blown air. Therefore, the indoor condenser 13 is a heating part that heats the blown air, which is the object to be heated, using one of the discharged refrigerants branched at the first three-way joint 12a as a heat source.

[0038] The inlet side of the second three-way joint 12b is connected to the refrigerant outlet of the indoor condenser 13. The inlet side of the heating expansion valve 14a is connected to one outlet 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 inlet of the four-way joint 12x is the high-pressure side passage 21b.

[0039] A high-pressure side on-off valve 22a is disposed in the high-pressure side passage 21b. The high-pressure side on-off valve 22a is an on-off valve that opens and closes the high-pressure side passage 21b. The high-pressure side on-off valve 22a is an electromagnetic valve whose opening and closing operation is controlled by a control voltage output from the control device 60. The high-pressure side on-off valve 22a can switch the refrigerant circuit by opening and closing the high-pressure side passage 21b. Therefore, the high-pressure side on-off valve 22a is an operation mode switching unit.

[0040] The four-way joint 12x is a joint part having four inlet / 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. Alternatively, a joint formed by combining two three-way joints can be used as the four-way joint 12x.

[0041] The heating expansion valve 14a is an upstream pressure reducing unit that reduces the pressure of the refrigerant flowing into the outdoor air heat exchanger 15, for example, in an outdoor air heat absorption heating mode, which will be described later. Furthermore, the heating expansion valve 14a is an upstream flow rate adjusting unit that adjusts the mass flow rate of the refrigerant flowing into the outdoor air heat exchanger 15.

[0042] The outlet of the heating expansion valve 14a is connected to the refrigerant inlet side of an outside air heat exchanger 15. The outside air heat exchanger 15 is an outside air heat exchanger that exchanges heat between the refrigerant flowing out of the heating expansion valve 14a and outside air blown by an outside air fan (not shown). The outside air heat exchanger 15 is located on the front side of the drive unit compartment. Therefore, when the vehicle is running, the running wind that flows into the drive unit compartment through the grill can hit the outside air heat exchanger 15.

[0043] The outdoor air heat exchanger 15 serves as an outdoor air side heat radiating section that radiates heat of the refrigerant to the outdoor air in a cooling mode, which will be described later, etc. Also, the outdoor air heat exchanger 15 serves as an outdoor air side heat absorbing section that causes the refrigerant to absorb heat of the outdoor air in a heating mode, etc.

[0044] An inlet side of a third three-way joint 12c is connected to a refrigerant outlet of the outdoor air 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 extending 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 low-pressure side passage 21c.

[0045] A low-pressure side on-off valve 22b is disposed in the low-pressure side passage 21c. The low-pressure side on-off valve 22b is an on-off valve that opens and closes the low-pressure side passage 21c. The basic configuration of the low-pressure side on-off valve 22b is similar to that of the high-pressure side on-off valve 22a. The low-pressure side on-off valve 22b can switch the refrigerant circuit by opening and closing the low-pressure side passage 21c. Therefore, the low-pressure side on-off valve 22b is an operation mode switching unit.

[0046] 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.

[0047] 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 an evaporator pressure reduction unit that reduces the pressure of the refrigerant flowing out from one outlet of the four-way joint 12x in the cooling mode, etc. Furthermore, the cooling expansion valve 14b is an evaporator flow rate adjustment unit that adjusts the mass flow rate of the refrigerant flowing into the indoor evaporator 18.

[0048] The interior evaporator 18 is disposed in an air conditioning case 51 of the interior air conditioning unit 50. The interior evaporator 18 is a cooling heat exchanger that exchanges heat between the low-pressure refrigerant decompressed by the cooling expansion valve 14b and the blown air blown into the vehicle cabin from the interior blower 52. The interior evaporator 18 evaporates the low-pressure refrigerant to exert a heat absorption effect, thereby cooling the blown air.

[0049] 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, but prevents the refrigerant from flowing from the fifth three-way joint 12e side to the refrigerant outlet side of the indoor evaporator 18.

[0050] Another outlet of the four-way joint 12x is connected to the other inlet side of a sixth three-way joint 12f via a cooling expansion valve 14c. The outlet of the sixth three-way joint 12f is connected to the inlet side of the refrigerant passage of the chiller 20.

[0051] The cooling expansion valve 14c is a chiller pressure reducing unit that reduces the pressure of the refrigerant flowing into the chiller 20 during a cooling / cooling mode, which will be described later, etc. Furthermore, the cooling expansion valve 14c is a chiller flow rate adjusting unit that adjusts the mass flow rate of the refrigerant flowing into the chiller 20 during a cooling / cooling mode, etc.

[0052] Furthermore, in a defrosting mode, which will be described later, cooling expansion valve 14c serves as a downstream pressure reduction unit that reduces the pressure of the refrigerant that flows out of outdoor air heat exchanger 15 and into chiller 20. Furthermore, cooling expansion valve 14c serves as a downstream flow rate adjustment unit that adjusts the mass flow rate of the refrigerant that flows out of outdoor air heat exchanger 15 and into chiller 20.

[0053] The chiller 20 is a cooling heat exchanger that exchanges heat between the low-pressure refrigerant decompressed by the cooling expansion valve 14c and the low-temperature heat medium circulating through the low-temperature heat medium circuit 40. The chiller 20 cools the low-temperature heat medium by evaporating the low-pressure refrigerant to absorb heat. Furthermore, in the defrost mode, the chiller 20 serves as a defrost heat absorption unit that absorbs defrosting heat generated by the battery 70 into the low-pressure refrigerant via the low-temperature heat medium.

[0054] The other inlet side of fourth three-way joint 12d 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 fourth three-way joint 12d.

[0055] The outlet of the fifth three-way joint 12e is connected to the inlet side of the accumulator 23. The accumulator 23 is a low-pressure gas-liquid separator that separates the refrigerant that flows into it into gas and liquid, and discharges the separated gas-phase refrigerant to the suction side of the compressor 11, while storing the separated liquid-phase refrigerant as surplus refrigerant for the cycle. The gas-phase refrigerant outlet of the accumulator 23 is connected to the suction side of the compressor 11.

[0056] Next, the low-temperature side heat medium circuit 40 will be described. The low-temperature side heat medium circuit 40 is a heat medium circuit that circulates a low-temperature side heat medium. In this embodiment, 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 coolant passage 70a of the battery 70, a heat medium passage of the chiller 20, etc.

[0057] The low-temperature side pump 41 is a low-temperature side heat medium pumping unit that pumps the low-temperature side heat medium that flows 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 outlet side of the heat medium passage of the chiller 20 is connected to the inlet side of the cooling water passage 70a of the battery 70.

[0058] The coolant passage 70a of the battery 70 is a coolant passage formed to cool the battery 70 by circulating a low-temperature heat medium cooled by the chiller 20. The coolant passage 70a is formed inside a battery case that houses a plurality of stacked battery cells.

[0059] 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.

[0060] In the low-temperature side heat medium circuit 40, the amount of heat exchanged between the refrigerant and the low-temperature side heat medium in the chiller 20 can be changed by changing the rotation speed of the low-temperature side pump 41.

[0061] Therefore, the low-temperature side pump 41 serves as an operation mode switching unit that switches the operation mode by changing the amount of heat exchange between the refrigerant and the low-temperature side heat medium in the chiller 20. More specifically, the low-temperature side pump 41 serves as an operation mode switching unit that switches the operation mode by switching whether or not heat exchange between the refrigerant and the low-temperature side heat medium is performed in the chiller 20.

[0062] Next, the interior air conditioning unit 50 will be described with reference to Figure 2. The interior air conditioning unit 50 is a unit that integrates multiple components to blow out air adjusted to an appropriate temperature to appropriate locations within the vehicle cabin for air conditioning. The interior air conditioning unit 50 is located inside the instrument panel at the front of the vehicle cabin.

[0063] The indoor air conditioning unit 50 is formed by accommodating an indoor fan 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 made of a resin (for example, polypropylene) that has a certain degree of elasticity and excellent strength.

[0064] 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.

[0065] An interior blower 52 is disposed downstream of the inside / outside air switching device 53 in the flow of blown air. The interior blower 52 is a blower that blows air taken in through the inside / outside air switching device 53 toward the vehicle interior. The rotation speed (i.e., blowing capacity) of the interior blower 52 is controlled by a control voltage output from the control device 60.

[0066] The indoor evaporator 18 and the indoor condenser 13 are arranged downstream in the flow of air blown by the indoor blower 52. The indoor evaporator 18 is arranged upstream in the flow of air blown from the indoor condenser 13. A cool air bypass passage 55 is formed in the air conditioning case 51, which allows the blown air that has passed through the indoor evaporator 18 to bypass the indoor condenser 13.

[0067] An air mix door 54 is disposed downstream of the indoor evaporator 18 in the air conditioning case 51 in the flow of blown air, and upstream of the indoor condenser 13 and the cold air bypass passage 55 in the flow of blown air.

[0068] The air mix door 54 adjusts the ratio of the volume of the blown air that passes through the indoor condenser 13 side to the volume of the blown air that passes through the cool air bypass passage 55 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.

[0069] Therefore, in the indoor air conditioning unit 50, by changing the opening degree of the air mix door 54, the amount of heat exchanged between the refrigerant and the blown air in the indoor condenser 13 can be changed.

[0070] Therefore, the air mix door 54 serves as an operation mode switching unit that switches the operation mode by changing the amount of heat exchange between the refrigerant and the blown air in the interior condenser 13. More specifically, the air mix door 54 serves as an operation mode switching unit that switches the operation mode by switching whether or not to perform heat exchange between the refrigerant and the blown air in the interior condenser 13.

[0071] A mixing space 56 is disposed downstream of the indoor condenser 13 and the cold air bypass passage 55 in the flow direction of the blown air. The mixing space 56 is a space where the blown air heated by the indoor condenser 13 and the blown air that has passed through the cold air bypass passage 55 and has not been heated are mixed.

[0072] Therefore, in the interior air conditioning unit 50, by adjusting the opening degree of the air mix door 54, it is possible to adjust the temperature of the blown air (that is, the conditioned air) that is mixed in the mixing space 56 and blown into the vehicle interior.

[0073] A plurality of openings (not shown) for blowing conditioned air toward various locations in the vehicle cabin are formed at the most downstream portion of the airflow of the air-conditioning case 51. A blowout mode door (not shown) for opening and closing each of the openings is disposed in each opening. The operation of the actuator for driving the blowout mode door is controlled by a control signal output from the control device 60.

[0074] Therefore, in the interior air conditioning unit 50, by switching the opening holes that the blow-out mode door opens and closes, conditioned air that has been adjusted to an appropriate temperature can be blown out to an appropriate location in the vehicle interior.

[0075] Next, the electrical control unit of this embodiment will be described using the block diagram of Figure 3. The control device 60 has a well-known microcomputer including a CPU, ROM, RAM, etc., and its peripheral circuits. The control device 60 performs various calculations and processes based on control programs stored in the ROM. Then, the control device 60 controls the operation of various control target devices connected to the output side based on the results of the calculations and processes.

[0076] A group of control sensors, such as an inside air temperature sensor 61a, an outside air temperature sensor 61b, a solar radiation sensor 61c, a discharge refrigerant temperature and pressure sensor 62a, a high-pressure side refrigerant temperature and pressure sensor 62b, an outside air side refrigerant temperature and pressure sensor 62c, an evaporator side refrigerant temperature and pressure sensor 62d, a chiller side refrigerant temperature and pressure sensor 62e, a low-temperature side heat medium temperature sensor 63b, a battery temperature sensor 64, and an air conditioning air temperature sensor 65, are connected to the input side of the control device 60.

[0077] The inside air temperature sensor 61a is an inside air temperature detector that detects the temperature inside the vehicle cabin (inside air temperature) Tr. The outside air temperature sensor 61b is an outside air temperature detector that detects the temperature outside the vehicle cabin (outside air temperature) Tam. The solar radiation sensor 61c is an solar radiation amount detector that detects the amount of solar radiation As irradiating into the vehicle cabin.

[0078] The discharge refrigerant temperature and pressure sensor 62 a is a discharge refrigerant temperature and pressure detection unit that detects the discharge refrigerant temperature Td and the discharge refrigerant pressure Pd of the refrigerant discharged from the compressor 11 .

[0079] The high-pressure side refrigerant temperature and pressure sensor 62b is a high-pressure side refrigerant temperature and pressure detection unit that detects the high-pressure side refrigerant temperature T1 and high-pressure side refrigerant pressure P1 of the refrigerant flowing out from the indoor condenser 13.

[0080] The outdoor air side refrigerant temperature and pressure sensor 62c is an outdoor unit side refrigerant temperature and pressure detection unit that detects the outdoor air side refrigerant temperature T2 and the outdoor air side refrigerant pressure P2 of the refrigerant flowing out from the outdoor air heat exchanger 15.

[0081] The evaporator-side refrigerant temperature and pressure sensor 62d is an evaporator-side refrigerant temperature and pressure detection unit that detects the evaporator-side refrigerant temperature Te and evaporator-side refrigerant pressure Pe of the refrigerant flowing out from the interior evaporator .

[0082] The chiller-side refrigerant temperature and pressure sensor 62e is a chiller-side refrigerant temperature and pressure detection unit that detects the chiller-side refrigerant temperature Tc and chiller-side refrigerant pressure Pc of the refrigerant flowing out from the refrigerant passage of the chiller 20.

[0083] In addition, 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.

[0084] The low-temperature side heat medium temperature sensor 63b is a low-temperature side heat medium temperature detection unit that detects the low-temperature side heat medium temperature TWL, which is the temperature of the low-temperature side heat medium flowing into the heat medium passage of the chiller 20.

[0085] The battery temperature sensor 64 is a battery temperature detection unit that detects the battery temperature TB, which is the temperature of the battery 70. The battery temperature sensor 64 has multiple temperature sensors and detects the temperature at multiple locations on the battery 70. This allows the control device 60 to detect the temperature difference and temperature distribution among the battery cells that make up the battery 70. Furthermore, the average value of the detection values ​​of the multiple temperature sensors is used as the battery temperature TB.

[0086] The conditioned air temperature sensor 65 is an conditioned air temperature detection unit that detects the blown air temperature TAV, which is the temperature of the blown air blown from the mixing space 56 into the vehicle interior.

[0087] Furthermore, an operation panel 69 located near the instrument panel at the front of the vehicle interior is connected to the input side of the control device 60, as shown in Fig. 3. The operation panel 69 is provided with various operation switches to be operated by the occupant. Operation signals from the various operation switches are input to the control device 60.

[0088] The various operation switches provided on the operation panel 69 specifically include an auto switch, an air conditioner switch, a heating switch, an air volume setting switch, a temperature setting switch, and the like.

[0089] 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 the interior evaporator 18 to cool the blown air. The heating switch is a heating request unit that requests the interior condenser 13 to heat the blown air. 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 interior.

[0090] Here, the control device 60 of this embodiment is an integrated unit configured with a control section 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 a control section that controls the operation of each control target device.

[0091] For example, in the control device 60, the component that controls the rotation speed of the compressor 11 constitutes a compressor control section 60a, and the component that controls the operation of the operation mode switching section constitutes an operation mode control section 60b.

[0092] Next, the operation of the vehicle air conditioner 1 of this embodiment with the above configuration will be described. The vehicle air conditioner 1 switches between various operation modes to condition the air in the vehicle compartment and adjust the temperature of the battery 70. The operation mode is switched by executing a control program stored in advance in the control device 60.

[0093] The control program is executed not only when the start switch (so-called ignition switch) of the vehicle system is turned on and the vehicle system is running, but also when the battery 70 is being charged from an external power source.

[0094] The control program reads detection signals from the control sensors and operation signals from the operation panel 69. Then, based on the read detection signals and operation signals, it calculates a target blowout temperature TAO, which is the target temperature of the air blown into the vehicle cabin. Furthermore, it selects an operation mode based on the detection signals, operation signals, target blowout temperature TAO, etc., and controls the operation of various controlled devices according to the selected operation mode.

[0095] Thereafter, the control routines, such as reading the above-mentioned detection signals and operation signals, calculating the target blown-out temperature TAO, selecting the operation mode, and controlling the various controlled devices, are repeated at each predetermined control cycle until the termination condition of the control program is met.

[0096] The target air temperature TAO is calculated using the following formula F1. TAO=Kset×Tset-Kr×Tr-Kam×Tam-Ks×As+C…(F1) Tset is the set temperature inside the vehicle cabin set by the temperature setting switch. Tr is the inside air temperature detected by the inside air temperature sensor 61a. Tam is the outside air temperature detected by the outside air temperature sensor 61b. As is the amount of solar radiation detected by the solar radiation sensor 61c. Kset, Kr, Kam, and Ks are control gains, and C is a correction constant. Each driving mode is explained below.

[0097] (a) Cooling mode The cooling mode is an operating mode in which cooled air is blown into the passenger compartment to cool the interior of the vehicle. The cooling mode is likely to be selected when the auto switch and air conditioner switch are on, the outside air temperature Tam is relatively high, or the target outlet temperature TAO is relatively low.

[0098] The cooling modes include a single cooling mode in which the vehicle cabin is cooled without cooling the battery 70, and a cooled / cooled mode in which the vehicle cabin is cooled while cooling the battery 70. In the control program of this embodiment, when the battery temperature TB detected by the battery temperature sensor 64 becomes equal to or higher than a predetermined reference upper limit temperature KTBH, an operation mode for cooling the battery 70 is executed.

[0099] (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, throttles the cooling expansion valve 14b to reduce the refrigerant pressure, fully closes the cooling expansion valve 14c, and fully closes the bypass-side flow control valve 14d. The control device 60 also closes the high-pressure side on-off valve 22a and the low-pressure side on-off valve 22b.

[0100] 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 air heat exchanger 15, the cooling expansion valve 14b which is in a throttled state, the indoor evaporator 18, the accumulator 23, and the intake port of the compressor 11.

[0101] Furthermore, in the indoor air conditioning unit 50 in the single cooling mode, the control device 60 controls the rotation speed of the indoor blower 52 based on the target blowing temperature TAO, with reference to a control map stored in advance in the control device 60.

[0102] The control device 60 also adjusts the opening of the air mix door 54 so that the blown air temperature TAV detected by the air conditioning air temperature sensor 65 approaches the target blown air temperature TAO. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0103] Therefore, in the heat pump cycle 10 in the single cooling mode, the indoor condenser 13 and the outdoor air 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. Here, in the operation mode in which the refrigerant is evaporated by the indoor evaporator 18, the refrigerant evaporation temperature in the indoor evaporator 18 is adjusted within a range that can suppress frost formation on the indoor evaporator 18.

[0104] In the interior air conditioning unit 50 in the single cooling mode, the air blown from the interior blower 52 is cooled by the interior evaporator 18. The air cooled by the interior evaporator 18 is reheated by heat exchange with the refrigerant in the interior condenser 13 depending on the opening degree of the air mix door 54. Then, the air whose temperature has been adjusted to approach the target outlet temperature TAO is blown into the vehicle compartment, thereby cooling the vehicle compartment.

[0105] (a-2) Cooling mode In the heat pump cycle 10 in the cooling / air-cooling mode, the control device 60 throttles the cooling expansion valve 14c in comparison with the single cooling mode.

[0106] 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 stand-alone 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 following order: the indoor condenser 13, the heating expansion valve 14a which is in a fully open state, the outdoor air heat exchanger 15, the cooling expansion valve 14c which is in a throttled 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.

[0107] In addition, in the low-temperature side heat medium circuit 40 in the cooling / cooling mode, the control device 60 operates the low-temperature side pump 41 so as to exert a predetermined reference pumping capacity. Therefore, in the low-temperature side heat medium circuit 40 in the cooling / cooling mode, the low-temperature side heat medium pumped from the low-temperature side pump 41 circulates through the heat medium passage of the chiller 20, the coolant passage 70a of the battery 70, and the suction port of the low-temperature side pump 41 in that order.

[0108] In the indoor air conditioning unit 50 in the cooling / cooling mode, the control device 60 controls the rotation speed of the indoor blower 52, the opening degree of the air mix door 54, etc., in the same way as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0109] Therefore, in the heat pump cycle 10 in the cooling / air-conditioning mode, the indoor condenser 13 and the outdoor air heat exchanger 15 function as condensers, and the indoor evaporator 18 and the chiller 20 function as evaporators, forming a vapor compression refrigeration cycle.

[0110] In the low-temperature side heat medium circuit 40 in the cooling / air-cooling mode, the low-temperature side heat medium that has flowed into the heat medium passage of the chiller 20 is cooled by heat exchange with the low-pressure side refrigerant that has been decompressed by the cooling expansion valve 14c. The low-temperature side heat medium cooled by the chiller 20 flows into the coolant passage 70a of the battery 70.

[0111] The low-temperature side heat medium that flows into the coolant passage 70a of the battery 70 absorbs heat generated by the battery 70, thereby cooling the battery 70. The low-temperature side heat medium that flows out of the coolant passage 70a of the battery 70 is sucked into the low-temperature side pump 41 and pumped to the heat medium passage of the chiller 20.

[0112] In the interior air conditioning unit 50 in the cooling / air-conditioning mode, the temperature-adjusted blown air is blown into the vehicle compartment, thereby cooling the vehicle compartment, as in the single cooling mode.

[0113] (b) Dehumidifying heating mode The dehumidifying and heating mode is an operating mode that dehumidifies and heats the vehicle cabin by reheating cooled and dehumidified ventilation air and blowing it into the passenger compartment. The dehumidifying and heating mode is likely to be selected when the auto switch and air conditioner switch are on, the outside air temperature Tam is in the intermediate temperature range, or the target outlet temperature TAO is in the intermediate temperature range.

[0114] The dehumidifying and heating modes include a single dehumidifying and heating mode in which the vehicle interior is dehumidified and heated without cooling the battery 70, and a cooling, dehumidifying and heating mode in which the battery 70 is cooled and the vehicle interior is dehumidified and heated.

[0115] (b-1) Single dehumidification and heating mode In the heat pump cycle 10 in the single dehumidifying and heating mode, the control device 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 control device 60 also closes the high-pressure side on-off valve 22a and the low-pressure side on-off valve 22b.

[0116] Therefore, in the heat pump cycle 10 in the single dehumidifying and 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 throttled state, the outdoor air heat exchanger 15, the cooling expansion valve 14b which is in a throttled state, the indoor evaporator 18, the accumulator 23, and the intake port of the compressor 11.

[0117] In the indoor air conditioning unit 50 in the single dehumidifying heating mode, the control device 60 controls the rotation speed of the indoor blower 52, the opening degree of the air mix door 54, etc., in the same way as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0118] Therefore, in the heat pump cycle 10 in the single 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.

[0119] Furthermore, in the single dehumidifying and heating mode, when the saturation temperature of the refrigerant in the outdoor air heat exchanger 15 is higher than the outdoor air temperature Tam, the outdoor air heat exchanger 15 functions as a condenser. When the saturation temperature of the refrigerant in the outdoor air heat exchanger 15 is lower than the outdoor air temperature Tam, the outdoor air heat exchanger 15 functions as an evaporator.

[0120] In the interior air conditioning unit 50 in the single dehumidifying and heating mode, the air blown from the interior blower 52 is cooled and dehumidified in the interior evaporator 18. The air cooled and dehumidified in the interior evaporator 18 is reheated in the interior condenser 13 depending on the opening degree of the air mix door 54. Then, the air whose temperature has been adjusted to approach the target blowing temperature TAO is blown into the vehicle cabin, thereby realizing dehumidifying and heating the vehicle cabin.

[0121] (b-2) Cooling, dehumidifying, and heating mode In the heat pump cycle 10 in the cooling-dehumidifying-heating mode, the control device 60 throttles the cooling expansion valve 14c in comparison with the single dehumidifying-heating mode.

[0122] Therefore, in the heat pump cycle 10 in the cooling / dehumidifying / heating mode, the refrigerant discharged from the compressor 11 circulates in the same manner as in the single dehumidifying / 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 following order: the indoor condenser 13, the heating expansion valve 14a in a throttling state, the outdoor air 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 connected in parallel with respect to the refrigerant flow.

[0123] In the low-temperature side heat medium circuit 40 in the cooling, dehumidifying, and heating mode, the control device 60 operates the low-temperature side pump 41, just as in the cooling and cooling mode. Therefore, in the low-temperature side heat medium circuit 40 in the cooling, dehumidifying, and heating mode, the low-temperature side heat medium pumped from the low-temperature side pump 41 circulates, just as in the cooling and cooling mode.

[0124] In the indoor air conditioning unit 50 in the cooling, dehumidifying, and heating mode, the control device 60 controls the rotation speed of the indoor blower 52, the opening degree of the air mix door 54, etc., in the same way as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0125] Therefore, in the heat pump cycle 10 in the cooling, 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 and chiller 20 function as evaporators, just like in the single dehumidifying and heating mode.

[0126] Furthermore, in the cooling / dehumidifying / heating mode, as in the single dehumidifying / heating mode, when the saturation temperature of the refrigerant in the outdoor air heat exchanger 15 is higher than the outdoor air temperature Tam, the outdoor air heat exchanger 15 functions as a condenser. When the saturation temperature of the refrigerant in the outdoor air heat exchanger 15 is lower than the outdoor air temperature Tam, the outdoor air heat exchanger 15 functions as an evaporator.

[0127] In the low-temperature side heat medium circuit 40 in the cooling, dehumidifying, and heating mode, the low-temperature side heat medium cooled by the chiller 20 flows into the coolant passage 70a of the battery 70, as in the cooling and cooling mode. This cools the battery 70.

[0128] In the interior air conditioning unit 50 in the cooling, dehumidifying, and heating mode, the temperature-adjusted blown air is blown into the vehicle compartment, as in the single dehumidifying and heating mode, thereby realizing dehumidifying and heating the vehicle compartment.

[0129] (c) Outdoor air heat absorption heating mode The outdoor air heat absorption heating mode is an operating mode that heats the vehicle cabin by blowing heated air into the cabin. The outdoor air heat absorption heating mode is likely to be selected when the auto switch is on, the outdoor air temperature Tam is relatively low, or the target outlet temperature TAO is relatively high. It is also selected when the heating switch on the operation panel is turned on.

[0130] In the outdoor air heat absorption heating mode, the refrigerant decompressed by the heating expansion valve 14a flows into the outdoor air heat exchanger 15, where the refrigerant absorbs heat from the outdoor air. The heat absorbed by the refrigerant from the outdoor air is used as a heat source to heat the blown air in the heating section. Therefore, the outdoor air heat absorption heating mode is a heating mode in which an object to be heated is heated.

[0131] The outside air heat absorption heating mode includes a sole outside air heat absorption heating mode in which the vehicle interior is heated without cooling the battery 70, and a cooled outside air heat absorption heating mode in which the battery 70 is cooled and the vehicle interior is heated.

[0132] (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 control device 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 control device 60 also closes the high-pressure side on-off valve 22a and opens the low-pressure side on-off valve 22b.

[0133] Therefore, 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 air heat exchanger 15, the low-pressure side passage 21c, the accumulator 23, and the intake port of the compressor 11.

[0134] Furthermore, the control device 60 controls the rotation speed of the compressor 11 so that the discharge refrigerant pressure Pd detected by the discharge refrigerant temperature / pressure sensor 62a approaches the heating target pressure PDO. The heating target pressure PDO is set so that the blown air can be appropriately heated by the indoor condenser 13.

[0135] The control device 60 also adjusts 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 the target degree of subcooling SCO. The degree of subcooling SC1 can be determined from the high-pressure side refrigerant temperature T1 and the high-pressure side refrigerant pressure P1 detected by the high-pressure side refrigerant temperature / pressure sensor 62b. The target degree of subcooling SCO is determined so that the coefficient of performance (COP) of the cycle approaches its maximum value.

[0136] In the indoor air conditioning unit 50 in the single outdoor air heat absorption heating mode, the control device 60 controls the rotation speed of the indoor blower 52, the opening degree of the air mix door 54, etc., in the same way as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0137] Therefore, in the heat pump cycle 10 in the outdoor air heat absorption heating mode, the indoor condenser 13 functions as a condenser and the outdoor air heat exchanger 15 functions as an evaporator, forming a vapor compression refrigeration cycle. In the outdoor air heat absorption heating mode, the refrigerant needs to absorb heat from the outdoor air in the outdoor air heat exchanger 15. Therefore, the refrigerant evaporation temperature in the outdoor air heat exchanger 15 in the outdoor air heat absorption heating mode is lower than the outdoor air temperature Tam.

[0138] In the interior air conditioning unit 50 in the single outside air heat absorption heating mode, the air blown from the interior blower 52 passes through the interior evaporator 18. The air that has passed through the interior evaporator 18 is heated by the interior condenser 13 depending on the opening degree of the air mix door 54. The air whose temperature has been adjusted to approach the target outlet temperature TAO is then blown into the vehicle cabin, thereby heating the vehicle cabin.

[0139] (c-2) Cooling outdoor air heat absorption heating mode In the heat pump cycle 10 in the cooled 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, and also opens the high pressure side opening / closing valve 22a.

[0140] Therefore, in the heat pump cycle 10 in the cooled 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 following order: the indoor condenser 13, the high-pressure side passage 21b, the cooling expansion valve 14c in a throttled state, the chiller 20, the accumulator 23, and the suction port of the compressor 11. In other words, the refrigerant circuit is switched to one in which the outdoor air heat exchanger 15 and the chiller 20 are connected in parallel with respect to the refrigerant flow.

[0141] In the low-temperature side heat medium circuit 40 in the cooled outdoor air heat absorption heating mode, the control device 60 operates the low-temperature side pump 41, just as in the cooling and cooling mode. Therefore, in the low-temperature side heat medium circuit 40 in the cooled outdoor air heat absorption heating mode, the low-temperature side heat medium pumped from the low-temperature side pump 41 circulates, just as in the cooling and cooling mode.

[0142] In the indoor air-conditioning unit 50 in the cooled outdoor air heat absorption heating mode, the control device 60 controls the rotation speed of the indoor blower 52, the opening degree of the air mix door 54, etc., in the same way as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0143] 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 air heat exchanger 15 and the chiller 20 function as evaporators.

[0144] In the low-temperature side heat medium circuit 40 in the cooled outside air heat absorption heating mode, similar to the cooling and cooling mode, the low-temperature side heat medium cooled by the chiller 20 flows into the coolant passage 70a of the battery 70. This cools the battery 70.

[0145] 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, thereby heating the vehicle compartment, as in the single outside air heat absorption heating mode.

[0146] (d) Hot gas heating mode The hot gas heating mode is an operation mode for heating the vehicle cabin. The hot gas heating mode is selected when the auto switch is on and the outside air temperature Tam is extremely low (below -10°C in this embodiment).

[0147] In the heat pump cycle 10 in the hot gas heating mode, the control device 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 control device 60 also opens the high-pressure side on-off valve 22a and closes the low-pressure side on-off valve 22b.

[0148] Therefore, in the heat pump cycle 10 in the hot gas heating mode, the refrigerant discharged from the compressor 11 circulates in the following order: first three-way joint 12a, indoor condenser 13, high-pressure side passage 21b, cooling expansion valve 14c in the throttled state, sixth three-way joint 12f, chiller 20, 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 the refrigerant circulates in the following order: first three-way joint 12a, bypass-side flow control valve 14d in the throttled state and disposed in the bypass passage 21a, sixth three-way joint 12f, chiller 20, accumulator 23, and the suction port of the compressor 11.

[0149] Furthermore, the control device 60 controls the rotation speed of the compressor 11 so that the chiller-side refrigerant pressure Pc approaches a predetermined target low pressure PSO1 for hot gas heating. The target low pressure PSO1 for hot gas heating is set so that the refrigerant evaporation temperature of the low-pressure side refrigerant in the chiller 20 is higher than the outside air temperature Tam.

[0150] Here, controlling the chiller-side refrigerant pressure Pc, which corresponds to the pressure of the refrigerant sucked into the compressor 11, so that it approaches a constant pressure is effective for stabilizing the discharge flow rate Gr (mass flow rate) of the compressor 11. The reason for this is that by making the refrigerant sucked into the compressor 11 a saturated gas-phase refrigerant at a constant pressure, the density of the refrigerant sucked into the compressor 11 can be made constant. Therefore, it is easy to stabilize the discharge flow rate Gr of the compressor 11 at the same rotation speed.

[0151] The control device 60 also controls the throttle opening of the cooling expansion valve 14c so that the refrigerant on the outlet side of the chiller 20 approaches saturated gas phase refrigerant, that is, so that the degree of superheat SHC of the refrigerant on the outlet side of the chiller 20 approaches 0°C. The degree of superheat SHC of the refrigerant on the outlet side of the chiller 20 can be estimated from the chiller side refrigerant temperature Tc and chiller side refrigerant pressure Pc detected by the chiller side refrigerant temperature and pressure sensor 62e.

[0152] The controller 60 also controls the throttle opening of the bypass-side flow control valve 14d so that the cycle pressure difference ΔP approaches the target pressure difference ΔP01 for the hot gas heating mode. The pressure difference ΔP is the value obtained by subtracting the chiller-side refrigerant pressure Pc from the discharge refrigerant pressure Pd.

[0153] The target high-low pressure difference ΔP01 for the hot gas heating mode is determined based on the target discharge temperature TAO and by referring to a control map stored in advance in the control device 60. The control map for the hot gas heating mode determines the target high-low pressure difference ΔP01 to increase as the target discharge temperature TAO increases so that the compression work of the compressor 11 becomes an appropriate amount of heat for heating the blown air.

[0154] Furthermore, in the low-temperature side heat medium circuit 40 in the hot gas heating mode, the control device 60 stops the low-temperature side pump 41.

[0155] In the indoor air conditioning unit 50 in the hot gas heating mode, the control device 60 controls the rotation speed of the indoor blower 52, the opening degree of the air mix door 54, etc., in the same way as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0156] Therefore, in the heat pump cycle 10 in the hot gas heating mode, the flow of refrigerant 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. The refrigerant that flows into the indoor condenser 13 dissipates heat into the blown air, reducing its enthalpy. This heats the blown air.

[0157] The refrigerant flowing out of the indoor condenser 13 flows through the high-pressure side passage 21b into the cooling expansion valve 14c and is reduced in pressure. The refrigerant with a relatively low enthalpy reduced in pressure by the cooling expansion valve 14c flows into the other inlet of the sixth three-way joint 12f.

[0158] The other refrigerant branched at the first three-way joint 12a flows into the bypass passage 21a. The refrigerant flowing into the bypass passage 21a is flow-regulated and decompressed by the bypass-side flow control valve 14d. The refrigerant with a relatively high enthalpy decompressed by the bypass-side flow control valve 14d flows into one inlet of the sixth three-way joint 12f.

[0159] At the sixth three-way joint 12f, the refrigerant flowing out from the cooling expansion valve 14c and the refrigerant flowing out from the bypass-side flow control valve 14d join together and are mixed. The refrigerant flowing out from the sixth three-way joint 12f flows into the chiller 20 and is further mixed homogeneously. The refrigerant flowing out from the refrigerant passage of the chiller 20 flows into the accumulator 23. The gas-phase refrigerant separated in the accumulator 23 is drawn into the compressor 11 and compressed again.

[0160] In the interior air conditioning unit 50 in the hot gas heating mode, the temperature-adjusted ventilation air is blown into the vehicle compartment, as in the single outside air heat absorption heating mode, thereby realizing heating of the vehicle compartment.

[0161] The hot gas heating mode is executed when the outdoor air temperature Tam is extremely low. Therefore, if the refrigerant flowing out of the indoor condenser 13 flows into the outdoor air heat exchanger 15, the refrigerant may radiate heat to the outdoor air in the outdoor air heat exchanger 15. If the refrigerant radiates heat to the outdoor air in the outdoor air heat exchanger 15, the amount of heat radiated by the refrigerant to the blown air in the indoor condenser 13 decreases, and the heating capacity of the blown air decreases.

[0162] In contrast, in the hot gas heating mode, the refrigerant circuit is switched to one that does not allow the refrigerant flowing out from the indoor condenser 13 to flow into the outdoor air heat exchanger 15, thereby preventing the refrigerant from releasing heat to the outdoor air in the outdoor air heat exchanger 15.

[0163] Furthermore, in the hot gas heating mode, the throttle opening of the cooling expansion valve 14c is controlled so that the refrigerant at the outlet side of the chiller 20 approaches saturated gas phase refrigerant. This allows the cycle to be balanced even if the refrigerant discharge capacity of the compressor 11 is increased and the amount of heat dissipated from the refrigerant to the blown air in the indoor condenser 13 is increased.

[0164] Therefore, in the 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.

[0165] As described above, the vehicle air conditioner 1 of this embodiment can provide comfortable air conditioning for the vehicle interior and appropriately adjust the temperature of the battery 70, which is an on-board device, by switching the operation mode.

[0166] In the outdoor air heat absorption heating mode, the refrigerant absorbs heat from the outdoor air in the outdoor air heat exchanger 15. Therefore, when the outdoor air temperature Tam is low, such as 0°C or lower, and the outdoor air heat absorption heating mode is executed, frost may form on the outdoor air heat exchanger 15.

[0167] If frost forms on the outdoor air heat exchanger 15, the frost will block the outdoor air passage of the outdoor air heat exchanger 15, reducing the heat exchange performance of the outdoor air heat exchanger 15. As a result, the outdoor air heat exchanger 15 will not be able to sufficiently absorb the heat of the outdoor air into the refrigerant, and the heating capacity of the indoor condenser 13 for heating the blown air will be reduced.

[0168] Therefore, in the vehicle air conditioner 1 of this embodiment, when frost forms on the outside air heat exchanger 15, operation is performed in a defrosting mode to remove the frost that has formed on the outside air heat exchanger 15. Furthermore, the vehicle air conditioner 1 switches between various defrosting modes to quickly and efficiently complete the defrosting of the outside air heat exchanger 15. The defrosting mode is switched by executing the control flow shown in FIG.

[0169] The control flow shown in Fig. 4 is a subroutine that is called at predetermined intervals when the heating mode (in this embodiment, the outdoor air heat absorption heating mode) is selected in the main routine of the control program. Each control step in the flowchart shown in Fig. 4 is a function realization unit that the control device 60 has.

[0170] 4, it is determined whether frost has formed on the outdoor air heat exchanger 15. In step S1, when a predetermined frosting condition is met, it is determined that frost has formed on the outdoor air heat exchanger 15. The frosting condition in this embodiment is met when the time during which the outdoor air side refrigerant temperature T2 detected by the outdoor air side refrigerant temperature / pressure sensor 62c is equal to or less than a predetermined frosting determination temperature KTf1 is equal to or greater than a predetermined frosting determination time KTmf1.

[0171] If it is determined in step S1 that frost has formed on the outdoor air heat exchanger 15, the process proceeds to step S2. If it is determined in step S1 that frost has not formed on the outdoor air heat exchanger 15, the process returns to the main routine.

[0172] In step S2, it is determined whether the refrigerant in chiller 20 can absorb sufficient heat for defrosting from battery 70 via the low-temperature side heat medium. Here, sufficient heat for defrosting means heat sufficient to complete defrosting of outdoor air heat exchanger 15. Specifically, in step S2, it is determined whether the low-temperature side heat medium temperature TWL detected by low-temperature side heat medium temperature sensor 63b is equal to or higher than a predetermined first reference heat medium temperature KTWL1.

[0173] If it is determined in step S2 that the low-temperature side heat medium temperature TWL is equal to or higher than the first reference heat medium temperature KTWL1, it is determined that the refrigerant can absorb sufficient heat for defrosting from the battery 70, and the process proceeds to step S4. In step S4, the endothermic defrosting mode is executed, and the process proceeds to step S7.

[0174] Furthermore, if it is determined in step S2 that the low-temperature side heat medium temperature TWL is not equal to or higher than the first reference heat medium temperature KTWL1, it is determined that the refrigerant cannot absorb sufficient defrosting heat from the battery 70, and the process proceeds to step S3.

[0175] In step S3, it is determined whether the refrigerant in the chiller 20 is capable of absorbing defrosting heat from the battery 70 via the low-temperature side heat medium. Specifically, in step S3, it is determined whether the low-temperature side heat medium temperature TWL is equal to or higher than a predetermined second reference heat medium temperature KTWL2. The second reference heat medium temperature KTWL2 is set to a value lower than the first reference heat medium temperature KTWL1.

[0176] If it is determined in step S3 that the low-temperature side heat medium temperature TWL is equal to or higher than the second reference heat medium temperature KTWL2, it is determined that the refrigerant can absorb the heat for defrosting from the battery 70, although the heat for defrosting is insufficient, and the process proceeds to step S5. In step S5, the endothermic hot gas defrosting mode is executed, and the process proceeds to step S7.

[0177] If it is determined in step S3 that the low-temperature side heat medium temperature TWL is not equal to or higher than the second reference heat medium temperature KTWL2, it is determined that the refrigerant cannot absorb the heat for defrosting from the battery 70, and the process proceeds to step S6. In step S6, the hot gas defrosting mode is executed, and the process proceeds to step S7.

[0178] In step S7, it is determined whether defrosting of the outdoor air heat exchanger 15 is completed. In step S7, when a predetermined termination condition is met, it is determined that defrosting of the outdoor air heat exchanger 15 is completed. In this embodiment, the termination condition is met when the time during which the outdoor air side refrigerant temperature T2 is equal to or higher than a predetermined termination judgment temperature KTf2 becomes equal to or higher than a predetermined termination judgment time KTmf2.

[0179] If it is determined in step S7 that the defrosting of the outdoor air heat exchanger 15 is completed, the process returns to the main routine. If it is determined in step S7 that the defrosting of the outdoor air heat exchanger 15 is not completed, the process returns to step S2. Each defrosting mode will be described below.

[0180] (e-1) Endothermic defrosting mode First, the endothermic defrosting mode executed in step S4 will be described. The endothermic defrosting mode includes a single endothermic defrosting mode in which the outside air heat exchanger 15 is defrosted without heating the vehicle interior, and a heating endothermic defrosting mode in which the vehicle interior is heated and the outside air heat exchanger 15 is defrosted.

[0181] In the control program of this embodiment, when the heating switch on the operation panel 69 is turned on during defrosting mode, a heating / defrosting mode is executed in which the interior of the vehicle is heated and the outside air heat exchanger 15 is defrosted.

[0182] (e-1-1) Single endothermic defrosting mode In the heat pump cycle 10 in the single heat absorption defrosting mode, the control device 60 fully opens the heating expansion valve 14a, fully closes the cooling expansion valve 14b, throttles the cooling expansion valve 14c, and fully closes the bypass-side flow control valve 14d. The control device 60 also closes the high-pressure side on-off valve 22a and the low-pressure side on-off valve 22b.

[0183] Therefore, in the heat pump cycle 10 in the single heat absorption defrosting mode, as shown by the solid arrows in Figure 5, 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 air heat exchanger 15, the cooling expansion valve 14c which is in a throttled state, the chiller 20, the accumulator 23, and the intake port of the compressor 11.

[0184] Furthermore, the control device 60 controls the rotation speed of the compressor 11 so that the outdoor air side refrigerant pressure P2 detected by the outdoor air side refrigerant temperature and pressure sensor 62c approaches a predetermined reference defrosting pressure KPdf.

[0185] The reference defrost pressure KPdf is set so that the temperature of the refrigerant flowing into the outdoor air heat exchanger 15 becomes the reference defrost temperature KTdf. The reference defrost temperature KTdf is set so that defrosting of the outdoor air heat exchanger 15 can be completed quickly without unnecessarily increasing the outdoor air-side refrigerant pressure P2. Therefore, the control device 60 controls the rotation speed of the compressor 11 so that the temperature of the refrigerant flowing into the outdoor air heat exchanger 15 approaches the reference defrost temperature KTdf.

[0186] In the low-temperature side heat medium circuit 40 in the single heat absorption and defrosting mode, the control device 60 operates the low-temperature side pump 41, as in the cooling and air-conditioning mode. Therefore, in the low-temperature side heat medium circuit 40 in the single heat absorption and defrosting mode, the low-temperature side heat medium pumped from the low-temperature side pump 41 circulates as shown by the dashed arrows in Fig. 5, as in the cooling and air-conditioning mode.

[0187] In addition, in the indoor air conditioning unit 50 in the single heat absorption defrosting mode, the control device 60 stops the indoor blower 52. The control device 60 also displaces the air mix door 54 so as to close the air passage on the indoor condenser 13 side. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0188] Therefore, in the heat pump cycle 10 in the single heat absorption defrost mode, the refrigerant discharged from the compressor 11 flows into the indoor condenser 13 via the first three-way joint 12a. In the single heat absorption defrost mode, the indoor blower 52 is stopped and the air mix door 54 closes the air passage on the indoor condenser 13 side, so the refrigerant that has flowed into the indoor condenser 13 flows out of the indoor condenser 13 without releasing heat to the blown air.

[0189] The refrigerant flowing out from the indoor condenser 13 flows into the outdoor air heat exchanger 15 via the heating expansion valve 14a, which is in a fully open state. As the refrigerant flowing into the outdoor air heat exchanger 15 flows through the outdoor air heat exchanger 15, it dissipates heat to the frost that has formed on the outdoor air heat exchanger 15 and condenses. This melts the frost that has formed on the outdoor air heat exchanger 15, and the outdoor air heat exchanger 15 is defrosted.

[0190] The refrigerant flowing out of the outside air heat exchanger 15 flows into the cooling expansion valve 14c and is decompressed. The low-pressure refrigerant decompressed by the cooling expansion valve 14c flows into the refrigerant passage of the chiller 20. The low-pressure refrigerant that has flowed into the chiller 20 absorbs the heat for defrosting from the low-temperature heat medium circulating in the heat medium passage and evaporates.

[0191] The refrigerant flowing out from chiller 20 flows into accumulator 23 and is separated into gas and liquid. The gas-phase refrigerant flowing out from accumulator 23 is drawn into compressor 11 and compressed again.

[0192] In the low-temperature side heat medium circuit 40 in the single heat absorption defrost mode, the low-temperature side heat medium pumped from the low-temperature side pump 41 flows into the heat medium passage of the chiller 20. The low-temperature side heat medium that has flowed into the chiller 20 is cooled by the low-temperature side refrigerant circulating in the refrigerant passage absorbing the heat for defrosting.

[0193] The low-temperature side heat medium that flows out from the heat medium passage of the chiller 20 flows into the coolant passage 70a of the battery 70. The low-temperature side heat medium that flows into the coolant passage 70a of the battery 70 absorbs the defrosting heat generated by the battery 70. The low-temperature side heat medium that flows out from the coolant passage 70a of the battery 70 is sucked into the low-temperature side pump 41 and is pressure-fed to the heat medium passage of the chiller 20 again.

[0194] (e-1-2) Heating and defrosting mode In the heat pump cycle 10 in the heating heat absorption defrosting mode, the control device 60 throttles the heating expansion valve 14a, fully closes the cooling expansion valve 14b, throttles the cooling expansion valve 14c, and fully closes the bypass-side flow control valve 14d. The control device 60 also closes the high-pressure side on-off valve 22a and the low-pressure side on-off valve 22b.

[0195] Therefore, in the heat pump cycle 10 in the heating heat absorption defrosting mode, as shown by the solid arrows in Figure 5, 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 throttled state, the outdoor air heat exchanger 15, the cooling expansion valve 14c which is in a throttled state, the chiller 20, the accumulator 23, and the intake port of the compressor 11.

[0196] Furthermore, the controller 60 controls the rotation speed of the compressor 11 so that the discharge refrigerant pressure Pd approaches the heating target pressure PDO, similarly to the outside air heat absorption heating mode.

[0197] Furthermore, the control device 60 controls the throttle opening of the heating expansion valve 14a so that the outside air side refrigerant pressure P2 approaches the reference defrosting pressure KPdf.

[0198] In the heating heat absorption and defrosting mode, the controller 60 operates the low-temperature pump 41 in the low-temperature side heat medium circuit 40, as in the cooling and air-conditioning mode. Therefore, in the heating heat absorption and defrosting mode, the low-temperature side heat medium pumped from the low-temperature pump 41 circulates in the low-temperature side heat medium circuit 40, as in the cooling and air-conditioning mode, as shown by the dashed arrows in Fig. 5 .

[0199] In the indoor air conditioning unit 50 in the heating endothermic defrosting mode, the control device 60 controls the rotation speed of the indoor blower 52, the opening degree of the air mix door 54, etc., in the same way as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0200] Therefore, in the heat pump cycle 10 in the heating heat absorption / defrosting mode, the refrigerant discharged from the compressor 11 flows into the indoor condenser 13 via the first three-way joint 12a. The refrigerant that has flowed into the indoor condenser 13 releases heat to the blown air and is condensed according to the opening degree of the air mix door 54.

[0201] The refrigerant flowing out from the indoor condenser 13 is decompressed by the heating expansion valve 14a. As a result, the outdoor air-side refrigerant pressure P2 approaches the reference defrosting pressure KPdf. That is, the temperature of the refrigerant flowing into the outdoor air heat exchanger 15 approaches the reference defrosting temperature KTdf.

[0202] The refrigerant decompressed by the heating expansion valve 14a flows into the outdoor air heat exchanger 15. As the refrigerant flows into the outdoor air heat exchanger 15, it dissipates heat to the frost on the outdoor air heat exchanger 15 and condenses. This melts the frost on the outdoor air heat exchanger 15, thereby defrosting the outdoor air heat exchanger 15. The subsequent operation of the heat pump cycle 10 is the same as in the single endothermic defrosting mode.

[0203] In the low-temperature side heat medium circuit 40 in the heating heat absorption defrost mode, as in the single heat absorption defrost mode, the low-temperature side heat medium that flows into the coolant passage 70a of the battery 70 absorbs the defrosting heat generated by the battery 70. Furthermore, the defrosting heat of the low-temperature side heat medium that flows into the chiller 20 is absorbed by the low-temperature side refrigerant flowing through the refrigerant passage.

[0204] In the interior air conditioning unit 50 in the heating heat absorption and defrosting mode, the temperature-adjusted blown air is blown into the vehicle compartment, as in the single outside air heat absorption and heating mode, thereby realizing heating of the vehicle compartment.

[0205] In the heating endothermic defrosting mode, the defrosting heat absorbed by the refrigerant in the chiller 20 is radiated not only to the frost on the outdoor air heat exchanger 15 but also to the blown air. Therefore, in the heating endothermic defrosting mode, the low-temperature side heat medium temperature TWL is more likely to drop than in the single endothermic defrosting mode. Therefore, the heating endothermic defrosting mode is more likely to transition to the endothermic hot gas defrosting mode than in the single endothermic defrosting mode.

[0206] (e-2) Endothermic hot gas defrosting mode Next, the endothermic hot gas defrosting mode executed in step S5 will be described. The endothermic defrosting mode includes a single endothermic hot gas defrosting mode in which the outside air heat exchanger 15 is defrosted without heating the vehicle interior, and a heating endothermic hot gas defrosting mode in which the outside air heat exchanger 15 is defrosted while the vehicle interior is heated.

[0207] (e-2-1) Single endothermic hot gas defrosting mode In the heat pump cycle 10 in the single heat absorption hot gas defrosting mode, the control device 60 fully opens or throttles 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 control device 60 also closes the high-pressure side on-off valve 22a and the low-pressure side on-off valve 22b.

[0208] 6, in the heat pump cycle 10 in the single-heat-endothermic hot gas defrosting mode, the refrigerant discharged from the compressor 11 circulates in the following order: first three-way joint 12a, indoor condenser 13, heating expansion valve 14a (fully open or throttled), outdoor air heat exchanger 15, cooling expansion valve 14c (throttled), sixth three-way joint 12f, chiller 20, 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 the refrigerant circulates in the following order: first three-way joint 12a, bypass-side flow control valve 14d (throttled) disposed in bypass passage 21a, sixth three-way joint 12f, chiller 20, accumulator 23, and the suction port of the compressor 11.

[0209] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the chiller-side refrigerant pressure Pc approaches a predetermined target low pressure PSO2 for endothermic hot gas defrosting. The target low pressure PSO2 for endothermic hot gas defrosting is set so that the refrigerant evaporation temperature of the low-pressure side refrigerant in the chiller 20 is lower than a second reference heat medium temperature KTWL2.

[0210] Similarly to the heating endothermic defrosting mode, the controller 60 controls the throttle opening of the heating expansion valve 14a so that the outdoor air side refrigerant pressure P2 approaches the reference defrosting pressure KPdf. Similarly to the hot gas heating mode, the controller 60 controls the throttle opening of the cooling expansion valve 14c so that the refrigerant on the outlet side of the chiller 20 approaches saturated gas phase refrigerant.

[0211] Furthermore, the control device 60 controls the throttle opening of the bypass-side flow control valve 14d so that the high-low pressure difference ΔP of the cycle approaches the target high-low pressure difference ΔP02 for the single heat absorption hot gas defrost mode. The target high-low pressure difference ΔP02 for the single heat absorption hot gas defrost mode is determined by referring to a control map stored in advance in the control device 60.

[0212] Here, the target high-low pressure difference ΔP02 for the single-heat-endothermic hot gas defrosting mode is set so as to quickly and efficiently complete the defrosting of the outdoor air heat exchanger 15. In other words, it is set so as not to unnecessarily increase the refrigerant discharge capacity of the compressor 11. For this reason, the discharge refrigerant pressure Pd may become equal to the reference defrost pressure KPdf. In this case, the heating expansion valve 14a is fully open.

[0213] In the low-temperature side heat medium circuit 40 in the single heat endothermic hot gas defrosting mode, the control device 60 operates the low-temperature side pump 41, as in the cooling and air-conditioning mode. Therefore, in the low-temperature side heat medium circuit 40 in the single heat endothermic hot gas defrosting mode, the low-temperature side heat medium pumped from the low-temperature side pump 41 circulates as shown by the dashed arrows in Fig. 6, as in the cooling and air-conditioning mode.

[0214] Furthermore, in the indoor air conditioning unit 50 in the single endothermic hot gas defrosting mode, similarly to the single endothermic defrosting mode, the control device 60 stops the indoor blower 52 and displaces the air mix door 54 so as to close the air passage on the indoor condenser 13 side. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0215] Therefore, in the heat pump cycle 10 in the single endothermic hot gas defrosting mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0216] That is, the flow of the refrigerant discharged from the compressor 11 (point a7 in FIG. 7) 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. In the single heat-absorbing hot gas defrosting mode, the indoor blower 52 is stopped and the air mix door 54 closes the air passage on the indoor condenser 13 side, so the refrigerant that has flowed into the indoor condenser 13 flows out of the indoor condenser 13 without releasing heat to the blown air.

[0217] The refrigerant flowing out from the indoor condenser 13 is decompressed by the heating expansion valve 14a (from point a7 to point c7 in FIG. 7). As a result, the outdoor air side refrigerant pressure P2 approaches the reference defrosting pressure KPdf. That is, the temperature of the refrigerant flowing into the outdoor air heat exchanger 15 approaches the reference defrosting temperature KTdf.

[0218] The refrigerant decompressed by the heating expansion valve 14a flows into the outdoor air heat exchanger 15. As the refrigerant flows into the outdoor air heat exchanger 15, it dissipates heat to the frost on the outdoor air heat exchanger 15 and condenses (from point c7 to point d7 in FIG. 7). This melts the frost on the outdoor air heat exchanger 15, and the outdoor air heat exchanger 15 is defrosted.

[0219] As described above, in the single endothermic hot gas defrosting mode, the heating expansion valve 14a may be fully opened. In this case, the state of the refrigerant changes as shown by the dashed line in FIG.

[0220] The refrigerant flowing out of the outside air heat exchanger 15 flows into the cooling expansion valve 14c and is decompressed (from point d7 to point e7 in FIG. 7). The low-pressure refrigerant decompressed by the cooling expansion valve 14c flows into the other inlet of the sixth three-way joint 12f.

[0221] The other refrigerant branched at the first three-way joint 12a flows into the bypass passage 21a. The refrigerant that has flowed into the bypass passage 21a is flow-regulated and decompressed by the bypass-side flow control valve 14d (from point a7 to point h7 in FIG. 7). The refrigerant with a relatively high enthalpy that has been decompressed by the bypass-side flow control valve 14d flows into one inlet of the sixth three-way joint 12f.

[0222] At the sixth three-way joint 12f, the refrigerant flowing out from the cooling expansion valve 14c and the refrigerant flowing out from the bypass-side flow control valve 14d join and are mixed (from point e7 to point f7, and from point h7 to point f7 in FIG. 7). The refrigerant flowing out from the sixth three-way joint 12f flows into the chiller 20. The low-pressure side refrigerant that has flowed into the chiller 20 absorbs defrosting heat from the low-temperature side heat medium circulating through the heat medium passage and evaporates (from point f7 to point g7 in FIG. 7).

[0223] The refrigerant flowing out from chiller 20 flows into accumulator 23 and is separated into gas and liquid. The gas phase refrigerant flowing out from accumulator 23 is drawn into compressor 11 and compressed again (from point g7 to point a7 in FIG. 7).

[0224] In the low-temperature side heat medium circuit 40 in the single heat absorption hot gas defrost mode, as in the single heat absorption defrost mode, the low-temperature side heat medium that flows into the coolant passage 70a of the battery 70 absorbs the defrosting heat generated by the battery 70. Furthermore, the defrosting heat of the low-temperature side heat medium that flows into the chiller 20 is absorbed by the low-temperature side refrigerant flowing through the refrigerant passage.

[0225] (e-2-2) Heating endothermic hot gas defrosting mode In the heat pump cycle 10 in the heating heat absorption hot gas defrosting mode, the control device 60 throttles 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 control device 60 also closes the high-pressure side on-off valve 22a and the low-pressure side on-off valve 22b.

[0226] 6, in the heat pump cycle 10 in the heating heat absorption hot gas defrosting mode, the refrigerant discharged from the compressor 11 circulates in the following order: first three-way joint 12a, indoor condenser 13, heating expansion valve 14a in the throttled state, outdoor air heat exchanger 15, cooling expansion valve 14c in the throttled state, sixth three-way joint 12f, chiller 20, 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 the refrigerant circulates in the following order: first three-way joint 12a, bypass-side flow control valve 14d in the throttled state and disposed in bypass passage 21a, sixth three-way joint 12f, chiller 20, accumulator 23, and the suction port of the compressor 11.

[0227] Furthermore, similarly to the single endothermic hot gas defrosting mode, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the chiller-side refrigerant pressure Pc approaches the target low pressure PSO2 for endothermic hot gas defrosting.

[0228] Similarly to the heating endothermic defrosting mode, the controller 60 controls the throttle opening of the heating expansion valve 14a so that the outdoor air side refrigerant pressure P2 approaches the reference defrosting pressure KPdf. Similarly to the hot gas heating mode, the controller 60 controls the throttle opening of the cooling expansion valve 14c so that the refrigerant on the outlet side of the chiller 20 approaches saturated gas phase refrigerant.

[0229] The controller 60 also controls the throttle opening of the bypass-side flow control valve 14d so that the high-low pressure difference ΔP of the cycle approaches the target high-low pressure difference ΔP03 for the heating heat absorption hot gas defrosting mode. The target high-low pressure difference ΔP03 for the heating heat absorption hot gas defrosting mode is determined by referring to a control map stored in advance in the controller 60.

[0230] Here, the target high-low pressure difference ΔP03 for the heating endothermic hot gas defrosting mode is set so as to enable proper heating of the vehicle interior. Proper heating of the vehicle interior requires more heat than is required for defrosting the outside air heat exchanger 15. For this reason, the target high-low pressure difference ΔP03 for the heating endothermic hot gas defrosting mode is greater than the target high-low pressure difference ΔP02 for the single endothermic hot gas defrosting mode.

[0231] In the low-temperature side heat medium circuit 40 in the heating endothermic hot gas defrosting mode, the control device 60 operates the low-temperature side pump 41, as in the cooling and air-conditioning mode. Therefore, in the low-temperature side heat medium circuit 40 in the single endothermic defrosting mode, the low-temperature side heat medium pumped from the low-temperature side pump 41 circulates as shown by the dashed arrows in Fig. 6, as in the cooling and air-conditioning mode.

[0232] In the indoor air conditioning unit 50 in the heating endothermic hot gas defrosting mode, the control device 60 controls the rotation speed of the indoor blower 52, the opening degree of the air mix door 54, etc., in the same way as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0233] Therefore, in the heat pump cycle 10 in the heating endothermic hot gas defrosting mode, the state of the refrigerant changes as shown in the Mollier diagram of Fig. 8. In Fig. 8, the states of the refrigerant at points equivalent in the cycle configuration to those in the Mollier diagram of Fig. 7 described in the single endothermic hot gas defrosting mode are indicated by the same reference characters (alphabet) as in Fig. 7, with only the subscripts (numbers) changed to match the diagram numbers. This also applies to the following Mollier diagrams.

[0234] That is, the flow of refrigerant discharged from compressor 11 (point a8 in FIG. 8) is branched at first three-way joint 12a. One of the refrigerant branches at first three-way joint 12a flows into indoor condenser 13. The refrigerant that flows into indoor condenser 13 exchanges heat with the blown air and releases heat to condense (from point a8 to point b8 in FIG. 8) depending on the opening degree of air mix door 54. This heats the blown air.

[0235] The refrigerant flowing out from the indoor condenser 13 is decompressed by the heating expansion valve 14a (from point b8 to point c8 in FIG. 8). As a result, the outdoor air side refrigerant pressure P2 approaches the reference defrosting pressure KPdf. That is, the temperature of the refrigerant flowing into the outdoor air heat exchanger 15 approaches the reference defrosting temperature KTdf.

[0236] The refrigerant decompressed by the heating expansion valve 14a flows into the outdoor air heat exchanger 15. As the refrigerant flows into the outdoor air heat exchanger 15, it dissipates heat to the frost on the outdoor air heat exchanger 15 and condenses (from point c8 to point d8 in FIG. 8). This melts the frost on the outdoor air heat exchanger 15, and defrosts the outdoor air heat exchanger 15. The subsequent operation of the heat pump cycle 10 is the same as in the single endothermic hot gas defrosting mode.

[0237] In the low-temperature side heat medium circuit 40 in the heating heat absorption hot gas defrost mode, as in the single heat absorption hot gas defrost mode, the low-temperature side heat medium that flows into the coolant passage 70a of the battery 70 absorbs the defrosting heat generated by the battery 70. Furthermore, the defrosting heat of the low-temperature side heat medium that flows into the chiller 20 is absorbed by the low-temperature side refrigerant flowing through the refrigerant passage.

[0238] In the interior air conditioning unit 50 in the heating heat absorption hot gas defrosting mode, the temperature-adjusted ventilation air is blown into the vehicle compartment, as in the single outside air heat absorption heating mode, thereby realizing heating of the vehicle compartment.

[0239] In the heating endothermic hot gas defrosting mode, the defrosting heat absorbed by the refrigerant in the chiller 20 is radiated not only to the frost on the outdoor air heat exchanger 15 but also to the blown air. Therefore, in the heating endothermic hot gas defrosting mode, the low-temperature side heat medium temperature TWL is more likely to drop than in the single endothermic hot gas defrosting mode. Therefore, the heating endothermic hot gas defrosting mode is more likely to transition to the hot gas defrosting mode than the single endothermic hot gas defrosting mode.

[0240] (e-3) Hot gas defrosting mode Next, the hot gas defrosting mode executed in step S6 will be described. The hot gas defrosting mode includes a single hot gas defrosting mode in which the outside air heat exchanger 15 is defrosted without heating the vehicle interior, and a heating hot gas defrosting mode in which the outside air heat exchanger 15 is defrosted while the vehicle interior is heated.

[0241] (e-3-1) Single hot gas defrost mode In the heat pump cycle 10 in the single hot gas defrosting mode, the control device 60 sets the heating expansion valve 14a in a fully open state or a throttled state, the cooling expansion valve 14b in a fully closed state, the cooling expansion valve 14c in a throttled state, and the bypass-side flow control valve 14d in a throttled state. The control device 60 also closes the high-pressure side on-off valve 22a and the low-pressure side on-off valve 22b.

[0242] 9, the refrigerant discharged from the compressor 11 circulates in the following order: first three-way joint 12a, heating expansion valve 14a (fully open or throttled), outdoor air heat exchanger 15, cooling expansion valve 14c (throttled), sixth three-way joint 12f, chiller 20, accumulator 23, and the suction port of compressor 11. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates in the following order: first three-way joint 12a, bypass-side flow control valve 14d (throttled) disposed in bypass passage 21a, sixth three-way joint 12f, chiller 20, accumulator 23, and the suction port of compressor 11.

[0243] Furthermore, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the chiller-side refrigerant pressure Pc approaches a predetermined target low pressure PSO3 for hot gas defrosting. The target low pressure PSO3 for hot gas defrosting is set to a pressure higher than the target low pressure PSO2 for endothermic hot gas defrosting.

[0244] Similarly to the heating endothermic defrosting mode, the controller 60 controls the throttle opening of the heating expansion valve 14a so that the outdoor air side refrigerant pressure P2 approaches the reference defrosting pressure KPdf. Similarly to the hot gas heating mode, the controller 60 controls the throttle opening of the cooling expansion valve 14c so that the refrigerant on the outlet side of the chiller 20 approaches saturated gas phase refrigerant.

[0245] Furthermore, the control device 60 controls the throttle opening of the bypass-side flow control valve 14d so that the high-low pressure difference ΔP of the cycle approaches the target high-low pressure difference ΔP04 for the individual hot gas defrost mode. The target high-low pressure difference ΔP04 for the individual hot gas defrost mode is determined by referring to a control map stored in advance in the control device 60.

[0246] Here, the target high-low pressure difference ΔP04 for the single hot gas defrost mode is set so as to quickly and efficiently complete the defrosting of the outdoor air heat exchanger 15. In other words, it is set so as not to unnecessarily increase the refrigerant discharge capacity of the compressor 11. For this reason, the discharge refrigerant pressure Pd may become equal to the reference defrost pressure KPdf. In this case, the heating expansion valve 14a is fully open.

[0247] Furthermore, in the low-temperature side heat medium circuit 40 in the single hot gas defrosting mode, the control device 60 stops the low-temperature side pump 41.

[0248] Furthermore, in the indoor air conditioning unit 50 in the single hot gas defrosting mode, as in the single endothermic defrosting mode, the control device 60 stops the indoor blower 52 and displaces the air mix door 54 so as to close the air passage on the indoor condenser 13 side. Furthermore, the control device 60 appropriately controls the operation of other controlled devices.

[0249] Therefore, in the heat pump cycle 10 in the single hot gas defrosting mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0250] That is, the flow of the refrigerant discharged from the compressor 11 (point a10 in FIG. 10) 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. In the single hot gas defrost mode, the indoor blower 52 is stopped and the air mix door 54 closes the air passage on the indoor condenser 13 side, so the refrigerant that has flowed into the indoor condenser 13 flows out of the indoor condenser 13 without releasing heat to the blown air.

[0251] The refrigerant flowing out from the indoor condenser 13 is decompressed by the heating expansion valve 14a (from point a10 to point c10 in FIG. 10). As a result, the outdoor air side refrigerant pressure P2 approaches the reference defrosting pressure KPdf. That is, the temperature of the refrigerant flowing into the outdoor air heat exchanger 15 approaches the reference defrosting temperature KTdf.

[0252] The refrigerant decompressed by the heating expansion valve 14a flows into the outdoor air heat exchanger 15. As the refrigerant that has flowed into the outdoor air heat exchanger 15 flows through the outdoor air heat exchanger 15, it dissipates heat to the frost that has formed on the outdoor air heat exchanger 15 and condenses (from point c10 to point d10 in FIG. 10). This melts the frost that has formed on the outdoor air heat exchanger 15, and defrosting of the outdoor air heat exchanger 15 is achieved.

[0253] As described above, in the single hot gas defrosting mode, the heating expansion valve 14a may be fully opened, as in the single endothermic hot gas defrosting mode. In this case, the state of the refrigerant changes as shown by the dashed line in FIG. 10.

[0254] The refrigerant flowing out of the outside air heat exchanger 15 flows into the cooling expansion valve 14c and is decompressed (from point d10 to point e10 in FIG. 10). The low-pressure refrigerant decompressed by the cooling expansion valve 14c flows into the other inlet of the sixth three-way joint 12f.

[0255] The other refrigerant branched at the first three-way joint 12a flows into the bypass passage 21a. The refrigerant that has flowed into the bypass passage 21a is flow-regulated and decompressed by the bypass-side flow control valve 14d (from point a10 to point h10 in FIG. 10). The refrigerant with a relatively high enthalpy that has been decompressed by the bypass-side flow control valve 14d flows into one inlet of the sixth three-way joint 12f.

[0256] At sixth three-way joint 12f, the refrigerant flowing out from cooling expansion valve 14c and the refrigerant flowing out from bypass-side flow control valve 14d join and are mixed (from point e10 to point g10, and from point h10 to point g10 in FIG. 10). The refrigerant flowing out from sixth three-way joint 12f flows into chiller 20, where it is further mixed homogeneously.

[0257] The refrigerant flowing out from chiller 20 flows into accumulator 23 and is separated into gas and liquid. The gas phase refrigerant flowing out from accumulator 23 is drawn into compressor 11 and compressed again (from point g10 to point a10 in FIG. 10).

[0258] (e-3-2) Heating hot gas defrosting mode In the heat pump cycle 10 in the heating hot gas defrosting mode, the control device 60 throttles 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 control device 60 also closes the high-pressure side on-off valve 22a and the low-pressure side on-off valve 22b.

[0259] 9, the refrigerant discharged from the compressor 11 circulates in the following order: first three-way joint 12a, heating expansion valve 14a in the throttled state, outdoor air heat exchanger 15, cooling expansion valve 14c in the throttled state, sixth three-way joint 12f, chiller 20, accumulator 23, and the suction port of compressor 11. At the same time, the refrigerant discharged from the compressor 11 is switched to a refrigerant circuit in which the refrigerant circulates in the following order: first three-way joint 12a, bypass-side flow control valve 14d in the throttled state and disposed in bypass passage 21a, sixth three-way joint 12f, chiller 20, accumulator 23, and the suction port of compressor 11.

[0260] Furthermore, similarly to the single hot gas defrost mode, the control device 60 controls the refrigerant discharge capacity of the compressor 11 so that the chiller-side refrigerant pressure Pc approaches the target low pressure PSO3 for hot gas defrosting.

[0261] Similarly to the heating endothermic defrosting mode, the controller 60 controls the throttle opening of the heating expansion valve 14a so that the outdoor air side refrigerant pressure P2 approaches the reference defrosting pressure KPdf. Similarly to the hot gas heating mode, the controller 60 controls the throttle opening of the cooling expansion valve 14c so that the refrigerant on the outlet side of the chiller 20 approaches saturated gas phase refrigerant.

[0262] The control device 60 also controls the throttle opening of the bypass-side flow control valve 14d so that the high-low pressure difference ΔP of the cycle approaches the target high-low pressure difference ΔP05 for the heating hot gas defrost mode. The target high-low pressure difference ΔP05 for the heating hot gas defrost mode is determined by referring to a control map stored in advance in the control device 60.

[0263] Here, the target high-low pressure difference ΔP05 for the heating hot gas defrost mode is set so as to be able to realize appropriate heating of the vehicle interior. To realize appropriate heating of the vehicle interior, more heat is required than is required to defrost the outside-air heat exchanger 15. For this reason, the target high-low pressure difference ΔP05 for the heating hot gas defrost mode is greater than the target high-low pressure difference ΔP04 for the single hot gas defrost mode.

[0264] Furthermore, in the low-temperature side heat medium circuit 40 in the heating hot gas defrosting mode, the control device 60 stops the low-temperature side pump 41.

[0265] In the indoor air conditioning unit 50 in the heating hot gas defrosting mode, the control device 60 controls the rotation speed of the indoor blower 52, the opening degree of the air mix door 54, etc., in the same way as in the single cooling mode. Furthermore, the control device 60 appropriately controls the operation of other control target devices.

[0266] Therefore, in the heat pump cycle 10 in the heating hot gas defrosting mode, the state of the refrigerant changes as shown in the Mollier diagram of FIG.

[0267] That is, the flow of refrigerant discharged from compressor 11 (point a11 in FIG. 11) is branched at first three-way joint 12a. One of the refrigerant branches at first three-way joint 12a flows into indoor condenser 13. The refrigerant that flows into indoor condenser 13 exchanges heat with the blown air, dissipating heat and condensing (from point a11 to point b11 in FIG. 11) depending on the opening degree of air mix door 54. This heats the blown air.

[0268] The refrigerant flowing out from the indoor condenser 13 is decompressed by the heating expansion valve 14a (from point b11 to point c11 in FIG. 11). As a result, the outdoor air side refrigerant pressure P2 approaches the reference defrosting pressure KPdf. That is, the temperature of the refrigerant flowing into the outdoor air heat exchanger 15 approaches the reference defrosting temperature KTdf.

[0269] The refrigerant decompressed by the heating expansion valve 14a flows into the outdoor air heat exchanger 15. As the refrigerant flows into the outdoor air heat exchanger 15, it dissipates heat to the frost on the outdoor air heat exchanger 15 and condenses (from point c11 to point d11 in FIG. 11). This melts the frost on the outdoor air heat exchanger 15, thereby defrosting the outdoor air heat exchanger 15. The subsequent operation of the heat pump cycle 10 is the same as in the single hot gas defrosting mode.

[0270] In the interior air conditioning unit 50 in the heating hot gas defrosting mode, the temperature-adjusted ventilation air is blown into the vehicle compartment, as in the single outside air heat absorption heating mode, thereby realizing heating of the vehicle compartment.

[0271] As described above, in the vehicle air conditioner 1 of this embodiment, defrosting of the outside air heat exchanger 15 can be completed quickly and efficiently by switching between various defrosting modes.

[0272] More specifically, in the (e-2) endothermic hot gas defrosting mode and the (e-3) hot gas defrosting mode of this embodiment, the refrigerant decompressed by the cooling expansion valve 14c is mixed with the refrigerant flowing out from the bypass-side flow control valve 14d, and is drawn into the compressor 11. That is, the refrigerant decompressed by the cooling expansion valve 14c is mixed with the refrigerant having a relatively high enthalpy, thereby balancing the cycle.

[0273] Therefore, in the (e-2) endothermic hot gas defrost mode and the (e-3) hot gas defrost mode, the refrigerant on the outlet side of the outdoor air heat exchanger 15 can be made to have a relatively low enthalpy, thereby increasing the amount of heat radiation from the refrigerant in the outdoor air heat exchanger 15. For example, in the (e-3-1) single hot gas defrost mode, the amount of heat radiation can be increased as shown from point c10 to point d10 in FIG.

[0274] As a result, the amount of heat dissipated from the refrigerant flowing through the outdoor air heat exchanger 15 to the frost on the outdoor air heat exchanger 15 is increased, and defrosting of the outdoor air heat exchanger 15 can be completed quickly.

[0275] Furthermore, in the (e-3) hot gas defrosting mode, the target low pressure PSO3 for hot gas defrosting is set to a pressure higher than the target low pressure PSO2 for endothermic hot gas defrosting. This allows the compressor 11 to draw in a refrigerant with a higher density. This also allows the discharge flow rate Gr of the compressor 11 to be increased at the same rotation speed.

[0276] As a result, in the (e-3) hot gas defrost mode, defrosting of the outdoor air heat exchanger 15 can be completed quickly without using the defrosting heat generated by the battery 70. In other words, defrosting of the outdoor air heat exchanger 15 can be completed quickly without needing a heat absorption source for generating heat for defrosting.

[0277] Furthermore, in the defrosting mode of this embodiment, as explained in steps S2 and S3 of FIG. 4, when the refrigerant in the chiller 20 is capable of absorbing the defrosting heat generated by the battery 70, the refrigerant in the chiller 20 is made to absorb the defrosting heat.

[0278] Therefore, in the (e-2) endothermic hot gas defrosting mode, even if the compression workload of the compressor 11 is reduced compared to the (e-3) hot gas defrosting mode, it is possible to complete defrosting of the outdoor air heat exchanger 15 more quickly. As a result, in the (e-2) endothermic hot gas defrosting mode, it is possible to complete defrosting of the outdoor air heat exchanger 15 more efficiently and quickly than in the (e-3) hot gas defrosting mode.

[0279] Furthermore, in the defrosting mode of this embodiment, as described in step S2 of Fig. 4, when the refrigerant in the chiller 20 is capable of absorbing sufficient heat for defrosting, it is possible to switch to the (e-1) endothermic defrosting mode. In the (e-1) endothermic defrosting mode, the compression work of the compressor 11 and the heat for defrosting can be used to perform condensation heat defrosting of the outdoor air heat exchanger 15.

[0280] Therefore, in the (e-1) endothermic defrosting mode, defrosting of the outdoor air heat exchanger 15 can be completed more efficiently and quickly than in the (e-2) endothermic hot gas defrosting mode and the (e-3) hot gas defrosting mode.

[0281] Furthermore, in the defrost mode of this embodiment, as explained in steps S2 and S3 of Fig. 4, whether or not the refrigerant in the chiller 20 is capable of absorbing defrost heat is determined using the low-temperature side heat medium temperature TWL. This makes it possible to easily determine whether or not the refrigerant in the chiller 20 is capable of absorbing defrost heat.

[0282] The vehicle air conditioner 1 of this embodiment also includes a heating expansion valve 14a as an upstream pressure reduction section. Therefore, in the defrosting mode, the refrigerant decompressed by the heating expansion valve 14a can be caused to flow into the outside air heat exchanger 15 to dissipate heat. This makes it possible to adjust the temperature of the refrigerant flowing into the outside air heat exchanger 15 while stabilizing the operating state of the compressor 11 without excessively reducing the rotation speed of the compressor 11.

[0283] Furthermore, in the defrost mode of this embodiment, the throttle opening of the heating expansion valve 14a is controlled so that the temperature of the refrigerant flowing into the outdoor air heat exchanger 15 approaches the reference defrost temperature KTdf. This prevents the pressure of the refrigerant flowing into the outdoor air heat exchanger 15 from increasing unnecessarily, and allows defrosting of the outdoor air heat exchanger 15 to be completed quickly.

[0284] The vehicle air conditioner 1 of this embodiment also includes the interior condenser 13 as a heating unit. Therefore, as described in (e-1-2) Heating heat absorption defrosting mode, (e-2-2) Heating heat absorption hot gas defrosting mode, and (e-3-2) Heating hot gas defrosting mode, it is possible to defrost the outside air heat exchanger 15 and heat the vehicle interior at the same time.

[0285] The present disclosure is not limited to the above-described embodiments, and various modifications can be made as follows within the scope of the present disclosure.

[0286] In the above embodiment, an example was described in which the heat pump cycle device according to the present disclosure is applied to a vehicle air conditioner, but the application of the heat pump cycle device is not limited to vehicle air conditioners. For example, the heat pump cycle device may be applied to an air conditioner that only conditions the air in the space to be air-conditioned without adjusting the temperature of a heat-generating device. For example, the heat pump cycle device may be applied to a hot water supply system that heats water for domestic use or the like as the object to be heated.

[0287] In the above embodiment, the battery 70 is used as a heat absorption source that generates heat for defrosting, but the heat absorption source is not limited to the battery 70. For example, the temperature of an inverter, a PCU, a transaxle, a control device for ADAS, etc. may be adjusted. Furthermore, the temperature of a plurality of in-vehicle devices may be adjusted.

[0288] The inverter supplies power to the motor generator, etc. The PCU is a power control unit that transforms electricity and distributes power. The transaxle is a power transmission mechanism that integrates the transmission, differential gear, etc. The ADAS control device is a control device for advanced driver assistance systems.

[0289] Furthermore, in the heat pump cycle apparatus according to the present disclosure, when only the (e-3) hot gas defrosting mode is executed as the defrosting mode without switching the operation mode, the heat pump cycle apparatus does not need to have a heat absorption source.

[0290] The configuration of the heat pump cycle device according to the present disclosure is not limited to the configuration disclosed in the above-described embodiment.

[0291] In the above embodiment, an example in which the indoor condenser 13 is used as the heating unit has been described, but the heating unit is not limited to the indoor condenser 13. For example, the heating unit may be one in which a high-temperature side pump, a water-refrigerant heat exchanger, a heater core, etc. are arranged in a high-temperature side heat medium circulation circuit that circulates the high-temperature side heat medium.

[0292] 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 basic configuration of the high-temperature side pump may be the same as that of the low-temperature side pump 41. The same type of fluid as the low-temperature side heat medium can be used as the high-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.

[0293] The heater core is disposed in the air passage of the indoor air conditioning unit 50 in the same manner as the indoor condenser 13. With this, in an outdoor air heat absorption heating mode, etc., 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.

[0294] In the high-temperature side heat medium circulation circuit, the amount of heat exchanged between the refrigerant and the high-temperature side heat medium in the water-refrigerant heat exchanger can be changed by changing the rotation speed of the high-temperature side pump.

[0295] Therefore, the high-temperature-side pump functions as an operation mode switching unit that switches the operation mode by changing the amount of heat exchange between the refrigerant and the high-temperature-side heat medium in the water-refrigerant heat exchanger. More specifically, the high-temperature-side pump functions as an operation mode switching unit that switches the operation mode by switching whether or not to exchange heat between the refrigerant and the high-temperature-side heat medium in the water-refrigerant heat exchanger.

[0296] In the above embodiment, an example has been described in which the accumulator 23 is used as a gas-liquid separator that stores excess liquid-phase refrigerant in the heat pump cycle 10, but a receiver may be used instead of the accumulator 23. The receiver is a high-pressure side gas-liquid separator that separates the refrigerant flowing out from the indoor condenser 13 into gas and liquid and stores excess liquid-phase refrigerant in the cycle.

[0297] Furthermore, if a receiver is used instead of the accumulator 23, the control device 60 can control the throttle opening of the cooling expansion valve 14c so that the superheat SHC becomes a predetermined reference superheat KSH during (c) the outdoor air heat absorption heating mode, etc.

[0298] 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. The predetermined temperature may be a temperature at which the indoor evaporator 18 can be inhibited.

[0299] 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 pressure of the refrigerant 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.

[0300] Furthermore, in the above embodiment, an example has been described in which the sixth three-way joint 12f, which is the bypass-side junction, is disposed on the upstream side of the refrigerant flow of the chiller 20, but the present invention is not limited to this.

[0301] For example, it may be disposed downstream of the refrigerant flow of chiller 20. In this case, the refrigerant flowing out of bypass-side flow control valve 14d and the refrigerant flowing out of the refrigerant passage of chiller 20 are homogeneously mixed when flowing through accumulator 23 and the refrigerant piping from sixth three-way joint 12f to the suction side of compressor 11.

[0302] For example, the sixth three-way joint 12f may be eliminated, and the end of the bypass passage 21a may be directly connected to the accumulator 23. Furthermore, a mixing section may be provided that homogeneously mixes the refrigerant decompressed by the cooling expansion valve 14c and the refrigerant flowing out from the bypass-side flow control valve 14d.

[0303] In the above embodiment, in the (e-1-1) single endothermic defrosting mode, an example has been described in which the indoor blower 52 is stopped and the air passage on the indoor condenser 13 side is closed by the air mix door 54 so that the blown air is not heated by the outdoor condenser 13, which is the heating unit, but this is not limiting.

[0304] For example, a heating unit bypass passage may be added that guides one of the refrigerants flowing out of the first three-way joint 12 to the inlet side of the second three-way joint 12, bypassing the heating unit. Then, in the (e-1-1) single heat absorption defrost mode, one of the refrigerants flowing out of the first three-way joint 12 may be made to flow into the heating unit bypass passage. This also applies to the (e-2-1) single heat absorption hot gas defrost mode and the (e-3-1) single hot gas defrost mode.

[0305] In the above embodiment, the refrigerant used in the heat pump cycle 10 is R1234yf, but the present invention is not limited to this. For example, R134a, R600a, R410A, R404A, R32, R407C, etc. may be used. Alternatively, a mixed refrigerant containing a mixture of two or more of these refrigerants may be used. Furthermore, carbon dioxide may be used as the refrigerant to configure a supercritical refrigeration cycle in which the high-pressure side refrigerant pressure is equal to or higher than the critical pressure of the refrigerant.

[0306] In the above embodiment, the refrigeration oil is PAG oil (i.e., polyalkylene glycol oil), but the present invention is not limited to this. For example, POE (i.e., polyol ester) may be used.

[0307] In the above embodiment, an example was described in which an ethylene glycol aqueous solution was used as the heat medium and the low-temperature heat medium, but this is not limiting. For example, a solution containing dimethylpolysiloxane or nanofluid, antifreeze, a water-based liquid refrigerant containing alcohol, or a liquid medium containing oil may also be used.

[0308] Furthermore, the group of control sensors connected to the input side of the control device 60 is not limited to the detection units disclosed in the above-described embodiment. Various detection units may be added as needed.

[0309] 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.

[0310] In the above embodiment, the vehicle air conditioner 1 capable of executing various operation modes has been described, but the heat pump cycle device according to the present disclosure does not need to be capable of executing all of the operation modes described above.

[0311] If at least the (e-3) hot gas defrosting mode can be executed, it is possible to obtain the effect of quickly completing defrosting of the outdoor air heat exchanger 15 without requiring a heat absorption source. Also, if at least the (e-2) endothermic hot gas defrosting mode can be executed, it is possible to obtain the effect of efficiently and quickly completing defrosting of the outdoor air heat exchanger 15.

[0312] Furthermore, the vehicle air conditioner 1 may be capable of executing other operation modes. For example, if the vehicle air conditioner 1 is provided with the above-mentioned evaporation pressure regulating valve, the vehicle air conditioner 1 may be capable of executing a parallel dehumidifying heating mode.

[0313] In the heat pump cycle 10 in the parallel dehumidifying and heating mode, the refrigerant discharged from the compressor 11 circulates in the following order: the indoor condenser 13, the heating expansion valve 14a in a throttled state, the outdoor air heat exchanger 15, the low-pressure side passage 21c, the accumulator 23, and the suction port of the compressor 11. At the same time, the refrigerant circuit can be switched to one in which the refrigerant discharged from the compressor 11 circulates in the following order: the indoor condenser 13, the high-pressure side passage 21b, the cooling expansion valve 14b in a throttled state, the indoor evaporator 18, the accumulator 23, and the suction port of the compressor 11. In other words, the refrigerant circuit can be switched to one in which the indoor evaporator 18 and the outdoor air heat exchanger 15 are connected in parallel with respect to the refrigerant flow.

[0314] In the parallel dehumidifying and heating mode, the control device 60 may appropriately control the operation of the other control target devices in the same manner as in the (b) dehumidifying and heating mode.

[0315] In the parallel dehumidifying and heating mode, the blown air cooled and dehumidified by the interior evaporator 18 is reheated by the interior condenser 13 and blown into the vehicle cabin. This achieves dehumidifying and heating the vehicle cabin. In the parallel dehumidifying and heating mode, the refrigerant decompressed by the heating expansion valve 14a is caused to flow into the outside air heat exchanger 15, where the refrigerant absorbs heat from the outside air. Therefore, the parallel dehumidifying and heating mode is included in the heating mode in which an object to be heated is heated.

[0316] In addition, in the above-mentioned (d) hot gas heating mode, etc., an example has been described in which the throttle opening of the cooling expansion valve 14c is controlled so that the refrigerant on the outlet side of the chiller 20 approaches saturated gas phase refrigerant, but this is not limited to this.

[0317] For example, the throttle opening of the cooling expansion valve 14c etc. may be controlled so that the refrigerant on the outlet side of the chiller 20 approaches a gas-liquid two-phase refrigerant that contains a moderate amount of liquid-phase refrigerant with refrigeration oil dissolved in it. In other words, the throttle opening of the cooling expansion valve 14c etc. may be controlled so that the dryness fraction Rxc of the refrigerant on the outlet side of the chiller 20 becomes a relatively high value.

[0318] In addition, in the (e-2) endothermic hot gas defrosting mode, (e-3) hot gas defrosting mode, etc. of the above-mentioned embodiment, an example has been described in which the throttle opening of the heating expansion valve 14a is controlled so that the outside air side refrigerant pressure P2 approaches the reference defrosting pressure KPdf, but the present invention is not limited to this.

[0319] For example, the throttle opening of the cooling expansion valve 14c may be controlled so that the outside air side refrigerant pressure P2 approaches the reference defrost pressure KPdf, and the throttle opening of the heating expansion valve 14a may be controlled so that the refrigerant on the outlet side of the chiller 20 approaches saturated gas phase refrigerant. For example, the opening ratio of the throttle opening of the heating expansion valve 14a to the throttle opening of the cooling expansion valve 14c may be controlled so that the outside air side refrigerant pressure P2 approaches the reference defrost pressure KPdf and the refrigerant on the outlet side of the chiller 20 approaches saturated gas phase refrigerant.

[0320] That is, the control device 60 may control the operation of at least one of the heating expansion valve 14a and the cooling expansion valve 14c so that the temperature of the refrigerant flowing into the outside air heat exchanger 15 approaches the reference defrost temperature KTdf.

[0321] In the above embodiment, when the heating switch on the operation panel 69 is turned on in the defrosting mode, the outside air heat exchanger 15 is defrosted and the vehicle interior is heated, but this is not limiting. For example, when the outside air temperature Tam is equal to or lower than a predetermined reference heating temperature, the outside air heat exchanger 15 may be defrosted and the vehicle interior may be heated.

[0322] Furthermore, the frosting condition and termination condition that can be employed in the control flow of FIG. 4 described above are not limited to the conditions disclosed in the above embodiment. For example, the frosting condition may be a condition that is met when the time during which the outdoor air temperature Tam is equal to or less than a predetermined frost determination outdoor air temperature KTamf becomes equal to or greater than a predetermined reference time. For example, the termination condition may be a condition that is met when the elapsed time since the start of defrosting mode operation becomes equal to or greater than a predetermined reference defrosting time.

[0323] The heat pump cycle device disclosed in this specification has the following features. (Item 1) a compressor (11) that compresses and discharges a refrigerant; an upstream branch portion (12a) that branches the flow of the refrigerant discharged from the compressor; a heating section (13) that heats an object to be heated using the refrigerant flowing out from one outlet of the upstream branch section as a heat source; an outside air heat exchange section (15) for exchanging heat between the refrigerant and outside air; an upstream pressure reducing section (14a) that reduces the pressure of the refrigerant flowing into the outside air heat exchange section; a downstream pressure reducing section (14c) that reduces the pressure of the refrigerant that has flowed out from the outside air heat exchange section; a bypass passage (21a) for guiding the refrigerant flowing out from the other outlet of the upstream branch portion to a suction port side of the compressor; a bypass-side flow rate adjusting section (14d) that adjusts the flow rate of the refrigerant flowing through the bypass passage, In a heating mode in which the heating object is heated by the heating unit, the refrigerant decompressed by the upstream decompression unit is caused to flow into the outside air heat exchange unit, and the refrigerant is caused to absorb heat from the outside air in the outside air heat exchange unit. In a defrosting mode for removing frost that has accumulated on the outdoor air heat exchange unit, the refrigerant that has flowed out from one outlet of the upstream branch unit is caused to flow into the outdoor air heat exchange unit to dissipate heat, the refrigerant that has flowed out from the outdoor air heat exchange unit is depressurized in the downstream pressure reduction unit, the refrigerant that has been depressurized in the downstream pressure reduction unit is mixed with the refrigerant that has flowed out from the bypass side flow rate adjustment unit, and the mixture is drawn into the compressor. (Item 2) Item 1. The heat pump cycle apparatus according to item 1, wherein in the defrosting mode, the refrigerant flowing out from one outlet of the upstream branch section is decompressed in the upstream decompression section, and the refrigerant flowing out from the upstream decompression section is caused to flow into the outside-air heat exchange section and dissipate heat. (Item 3) 3. The heat pump cycle apparatus according to claim 1, wherein in the defrosting mode, the refrigerant flowing out from one outlet of the upstream branch section is caused to flow into the heating section to heat the object to be heated, the refrigerant flowing out from the heating section is depressurized in the upstream pressure reduction section, and the refrigerant flowing out from the upstream pressure reduction section is caused to flow into the outside-air heat exchange section to dissipate heat. (Item 4) 4. The heat pump cycle apparatus according to item 2 or 3, wherein, during the defrosting mode, operation of at least one of the upstream pressure reduction section and the downstream pressure reduction section is controlled so that the temperature of the refrigerant flowing into the outdoor air heat exchange section approaches a predetermined reference defrosting temperature (KTdf). (Item 5) a defrosting heat absorption section (20) that absorbs defrosting heat used for defrosting the outside air heat exchange section into the refrigerant, 5. The heat pump cycle apparatus according to any one of items 1 to 4, wherein, during the defrosting mode and when the refrigerant is capable of absorbing the defrosting heat in the defrosting heat absorption section, the refrigerant is caused to absorb the defrosting heat in the defrosting heat absorption section.

[0324] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. a compressor (11) that compresses and discharges a refrigerant; an upstream branching portion (12a) that branches the flow of the refrigerant discharged from the compressor; a heating section (13) that heats an object to be heated using the refrigerant flowing out from one outlet of the upstream branch section as a heat source; an outside air heat exchange section (15) for exchanging heat between the refrigerant and outside air; an upstream pressure reducing section (14a) that reduces the pressure of the refrigerant flowing into the outside air heat exchange section; a downstream pressure reducing section (14c) that reduces the pressure of the refrigerant flowing out from the outside air heat exchange section; a bypass passage (21a) for guiding the refrigerant flowing out from the other outlet of the upstream branch portion to a suction port side of the compressor; a bypass-side flow rate adjusting section (14d) that adjusts the flow rate of the refrigerant flowing through the bypass passage, In a heating mode in which the heating object is heated by the heating unit, the refrigerant decompressed by the upstream decompression unit is caused to flow into the outside air heat exchange unit, and the refrigerant is caused to absorb heat from the outside air in the outside air heat exchange unit. In a defrosting mode for removing frost that has accumulated on the outdoor air heat exchange unit, the refrigerant that has flowed out from one outlet of the upstream branch unit is caused to flow into the outdoor air heat exchange unit to dissipate heat, the refrigerant that has flowed out from the outdoor air heat exchange unit is depressurized in the downstream pressure reduction unit, the refrigerant that has been depressurized in the downstream pressure reduction unit is mixed with the refrigerant that has flowed out from the bypass side flow rate adjustment unit, and the mixture is drawn into the compressor.

2. 2. The heat pump cycle apparatus according to claim 1, wherein in the defrosting mode, the refrigerant flowing out from one outlet of the upstream branch section is decompressed in the upstream decompression section, and the refrigerant flowing out from the upstream decompression section is caused to flow into the outside air heat exchange section to dissipate heat.

3. 2. The heat pump cycle device according to claim 1, wherein in the defrosting mode, the refrigerant flowing out from one outlet of the upstream branch section is caused to flow into the heating section to heat the object to be heated, the refrigerant flowing out from the heating section is depressurized in the upstream pressure reduction section, and the refrigerant flowing out from the upstream pressure reduction section is caused to flow into the outdoor air heat exchange section to dissipate heat.

4. 4. The heat pump cycle apparatus according to claim 2, wherein, during the defrosting mode, operation of at least one of the upstream pressure reducing section and the downstream pressure reducing section is controlled so that the temperature of the refrigerant flowing into the outdoor air heat exchange section approaches a predetermined reference defrosting temperature (KTdf).

5. a defrosting heat absorption section (20) that absorbs defrosting heat used for defrosting the outside air heat exchange section into the refrigerant, 4. The heat pump cycle apparatus according to claim 1, wherein, during the defrosting mode and when the refrigerant is capable of absorbing the defrosting heat in the defrosting heat absorption section, the refrigerant is caused to absorb the defrosting heat in the defrosting heat absorption section.

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