Heat pump system for vehicle and air conditioning device for vehicle

Abstract

An ECU (3) is capable of executing a maximum cooling mode. At this time, the ECU (3) drives each part of a heat medium circuit (2) so that one of a first heat exchanger (11) and a second heat exchanger (12) executes a heat dissipation function, the other executes a heat absorption function, and an external heat exchanger (23) executes a heat dissipation function. Then, the ECU (3) discharges air that passes through said one of the first heat exchanger (11) and the second heat exchanger (12) but does not pass through the other to the outside of a cabin from discharge openings (14, 141, 142). In addition, the ECU (3) drives an air path switching mechanism (15) so that air that passes through the other of the first heat exchanger (11) and the second heat exchanger (12) but does not pass through said one of the first heat exchanger (11) and the second heat exchanger (12) is blown out into the cabin from a blowout opening (13).

Description

Vehicle heat pump system, vehicle air conditioning system CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2023-203804, filed on December 1, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a heat pump system for a vehicle and an air conditioning device for a vehicle.

[0003] Conventionally, a vehicle heat pump system is known that regulates the temperature of heat-generating components mounted on a vehicle and conditions the vehicle interior. Hereinafter, the heat-generating components mounted on a vehicle are referred to as "vehicle heat-generating components," and the vehicle heat pump system may be simply referred to as "system." The system described in Patent Document 1 includes a heat medium circuit having a refrigeration cycle and a coolant circuit, and an air conditioning system that conditions the vehicle interior. The refrigeration cycle includes a compressor, an internal condenser, an external condenser, an evaporator, a chiller, and other components connected by refrigerant piping. An external condenser and a chiller are provided outside the air conditioning system. The chiller is a heat exchanger that exchanges heat between the low-temperature, low-pressure refrigerant flowing through the refrigeration cycle and the coolant flowing through the coolant circuit. The coolant circuit is provided with a vehicle heat-generating component heat exchanger that cools the vehicle heat-generating components. Meanwhile, an evaporator and an internal condenser are arranged in this order from the upstream side in the air passage of the air conditioning system. In this system, the air flowing through the ventilation duct is cooled by a condenser, and then the heat of the refrigerant flowing through the internal condenser is dissipated to a portion of the cooled air, which is then discharged to the outside of the vehicle through a purge passage.Patent Document 1 describes that the amount of heat dissipated from the refrigerant in the refrigeration cycle is increased by the internal condenser and the external condenser, thereby improving the cooling capacity of the vehicle heat-generating component heat exchanger.

[0004] Chinese Patent Application Publication No. 110549816

[0005] However, the system described in Patent Document 1 is inefficient because, after cooling the air in the condenser, a portion of the cooled air is reheated in the internal condenser and then discharged outside the vehicle. That is, this system dissipates a portion of the energy used to compress and discharge the refrigerant in the compressor to cool the air in the evaporator outside the vehicle, resulting in a large energy loss and a problem of reduced cooling efficiency for the vehicle interior and for cooling heat-generating vehicle components.

[0006] The present disclosure aims to improve the efficiency of vehicle heat pump systems and vehicle air conditioners.

[0007] According to one aspect of the present disclosure, a vehicle heat pump system includes: an air conditioning case having an air passage through which air drawn in from outside the vehicle compartment and air drawn in from inside the vehicle compartment flow; a first heat exchanger provided in the air passage of the air conditioning case and performing heat exchange between the air flowing in the air passage and a heat medium; a second heat exchanger provided in the air passage of the air conditioning case downstream of the first heat exchanger and performing heat exchange between the air flowing in the air passage and the heat medium; an outlet opening provided in the air conditioning case downstream of the first heat exchanger and the second heat exchanger and through which air blown into the vehicle compartment from the air passage flows; and an exhaust opening provided in the air conditioning case downstream of the first heat exchanger and through which air discharged to the outside of the vehicle compartment from the air passage flows. an air path switching mechanism that can switch the air flow path within the ventilation path between a state in which air flowing through the ventilation path passes through the first heat exchanger but not the second heat exchanger and flows to the outlet opening or the exhaust opening, and a state in which air flowing through the ventilation path passes through the second heat exchanger but not the first heat exchanger and flows to the outlet opening or the exhaust opening; an external heat exchanger that is provided in a space outside the air conditioning case and performs heat exchange between air outside the vehicle cabin and the heat medium; a heat medium circuit that connects the first heat exchanger, the second heat exchanger, and the external heat exchanger with piping through which the heat medium flows, and has a flow path switching valve in the piping that switches the flow of the heat medium; and an electronic control device that controls the operation of each part of the air path switching mechanism and the heat medium circuit, wherein the function of radiating heat from the heat medium flowing inside the heat exchanger to a material outside the heat exchanger is called a heat release function and the function of absorbing heat from a material outside the heat exchanger to the heat medium flowing inside the heat exchanger is called a heat absorption function, The electronic control device is capable of executing a maximum cooling mode in which the electronic control device drives each part of the heat medium circuit so that one of the first and second heat exchangers performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and drives the air path switching mechanism so that air that passes through one of the first and second heat exchangers but not the other is discharged outside the vehicle cabin through the exhaust opening, and air that passes through the other of the first and second heat exchangers but not the one is blown into the vehicle cabin through the blow-out opening.

[0008] According to this, by providing one of the first and second heat exchangers and the external heat exchanger with a heat dissipation function, it is possible to increase the amount of heat dissipated from the heat medium in the heat medium circuit to external substances (i.e., the air discharged from the air conditioning case to the outside of the vehicle cabin and the air outside the vehicle cabin). In the heat medium circuit, the amount of heat dissipated by the heat medium corresponds to the sum of the work load of the compressor in the refrigeration cycle and the amount of heat absorbed by the heat medium. Therefore, the vehicle heat pump system can achieve maximum performance. In this case, the vehicle heat pump system discharges air that passes through one of the first and second heat exchangers (i.e., the heat dissipation heat exchanger) but not the other to the outside of the vehicle cabin through the exhaust opening. In other words, since the system does not perform the process of reheating air cooled by a heat absorption heat exchanger in a heat dissipation heat exchanger as in Patent Document 1, no energy loss occurs. Therefore, the vehicle heat pump system can achieve higher efficiency than the configuration of Patent Document 1.

[0009] According to another aspect of the present disclosure, a vehicle air conditioning system is mounted on a vehicle together with a heat medium circuit that connects a first heat exchanger, a second heat exchanger, and an external heat exchanger with piping through which a heat medium flows, and that has a flow path switching valve in the piping for switching the flow of the heat medium, and includes: an air conditioning case having an air passage through which air drawn in from outside the vehicle compartment and air drawn in from inside the vehicle compartment flows; a first heat exchanger that is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing in the air passage and the heat medium; a second heat exchanger that is provided in the air passage of the air conditioning case downstream of the first heat exchanger and performs heat exchange between the air flowing in the air passage and the heat medium; an outlet opening that is provided in the air conditioning case downstream of the first heat exchanger and the second heat exchanger, and through which air blown into the vehicle compartment from the air passage flows; and an exhaust opening that is provided in the air conditioning case downstream of the first heat exchanger and through which air discharged to the outside of the vehicle compartment from the air passage flows. an air path switching mechanism that can switch the air flow path in the ventilation duct between a state in which air flowing through the ventilation duct passes through the first heat exchanger but not the second heat exchanger and flows to the blow-out opening or the exhaust opening, and a state in which air flowing through the ventilation duct passes through the second heat exchanger but not the first heat exchanger and flows to the blow-out opening or the exhaust opening; and an electronic control device that controls the operation of the air path switching mechanism and each part of the heat medium circuit, wherein the external heat exchanger is provided in a space outside the air conditioning case and performs heat exchange between the air outside the vehicle cabin and the heat medium, and when a function of radiating heat from the heat medium flowing inside the heat exchanger to a material outside the heat exchanger is called a heat radiation function and a function of absorbing heat from a material outside the heat exchanger into the heat medium flowing inside the heat exchanger is called a heat absorption function, The electronic control device is capable of executing a maximum cooling mode in which the electronic control device drives each part of the heat medium circuit so that one of the first and second heat exchangers performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and drives the air path switching mechanism so that air that passes through one of the first and second heat exchangers but not the other is discharged outside the vehicle cabin through the exhaust opening, and air that passes through the other of the first and second heat exchangers but not the one is blown into the vehicle cabin through the blow-out opening.

[0010] As a result, the vehicle air conditioning system according to another aspect of the present disclosure can also achieve the same effects as the vehicle heat pump system according to one aspect of the present disclosure.

[0011] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below.

[0012] 1 is a cross-sectional view showing a cooling mode in a vehicle air conditioner according to a first embodiment. FIG. 2 is a circuit diagram showing a cooling mode in a heat medium circuit according to the first embodiment. FIG. 3 is a cross-sectional view showing a heating mode in a vehicle air conditioner according to the first embodiment. FIG. 4 is a circuit diagram showing a heating mode from spring to summer in a heat medium circuit according to the first embodiment. FIG. 5 is a circuit diagram showing a heating mode from autumn to winter and a maximum heating mode in a heat medium circuit according to the first embodiment. FIG. 6 is a cross-sectional view showing a maximum cooling mode in a vehicle air conditioner according to the first embodiment. FIG. 7 is a circuit diagram showing a maximum cooling mode in a heat medium circuit according to the first embodiment. FIG. 8 is a cross-sectional view showing a maximum heating mode in a vehicle air conditioner according to the first embodiment. FIG. 9 is a cross-sectional view showing a state during transition from the maximum cooling mode to the cooling mode in a vehicle air conditioner according to the first embodiment. FIG. 10 is a cross-sectional view showing a cooling mode in a vehicle air conditioner according to a second embodiment. FIG. 11 is a circuit diagram showing a cooling mode in a heat medium circuit according to the second embodiment. FIG. 11 is a cross-sectional view showing a heating mode in a vehicle air conditioner according to a third embodiment. FIG. 12 is a circuit diagram showing a heating mode in a heat medium circuit according to the third embodiment. FIG. 13 is a cross-sectional view showing a maximum cooling mode in a vehicle air conditioner according to a fourth embodiment. FIG. 14 is a circuit diagram showing a maximum cooling mode in a heat medium circuit according to the fourth embodiment. FIG. 10 is a cross-sectional view showing a maximum cooling mode in a vehicle air conditioner according to a sixth embodiment. FIG. 11 is a circuit diagram showing a maximum cooling mode in a heat medium circuit according to the sixth embodiment. FIG. 12 is a cross-sectional view showing a maximum heating mode in a vehicle air conditioner according to a seventh embodiment. FIG. 13 is a circuit diagram showing a maximum heating mode in a heat medium circuit according to the seventh embodiment. FIG. 14 is a circuit diagram showing a maximum cooling mode in a heat medium circuit according to an eighth embodiment. FIG. 15 is a circuit diagram showing a maximum heating mode in a heat medium circuit according to the eighth embodiment. FIG. 16 is a circuit diagram showing a heat medium circuit according to a ninth embodiment. FIG. 17 is a cross-sectional view showing a heating mode and a heating mode when frost or the like has adhered to the external heat exchanger in a vehicle air conditioner according to a fifth embodiment. FIG. 18 is a circuit diagram showing a heating mode and a heating mode when frost or the like has adhered to the external heat exchanger in a heat medium circuit according to the fifth embodiment.

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals, and description thereof will be omitted.

[0014] (First Embodiment) A first embodiment will be described. A vehicle heat pump system of this embodiment adjusts the temperature of heat-generating components mounted in a vehicle and conditions the interior of the vehicle. As shown in FIGS. 1 and 2 , the vehicle heat pump system includes a vehicle air conditioner 1, a heat medium circuit 2, and an electronic control unit 3. Hereinafter, the vehicle air conditioner 1 will be referred to as the "air conditioner 1," and the electronic control unit 3 will be referred to as the "ECU 3." ECU stands for Electronic Control Unit.

[0015] <Configuration of Air Conditioner 1> First, we will explain the configuration of the air conditioner 1. As shown in Fig. 1, the air conditioner 1 is a reheat type and includes an air conditioning case 10, a first heat exchanger 11, a second heat exchanger 12, a plurality of outlet openings 13, an exhaust opening 14, and an air path switching mechanism 15. The first heat exchanger 11 and the second heat exchanger 12 constitute part of the heat medium circuit 2.

[0016] The air conditioning case 10 is made of a resin material such as polypropylene, and has an air passage 16 through which air flows inside. The air conditioning case 10 is provided with an air intake port 17, a plurality of outlet openings 13, and an exhaust opening 14. A blower 18, a first heat exchanger 11, a second heat exchanger 12, an air passage switching mechanism 15, and the like are provided inside the air conditioning case 10.

[0017] The air conditioner 1 is configured to selectively introduce air outside the vehicle cabin (hereinafter referred to as "outside air") and air inside the vehicle cabin (hereinafter referred to as "inside air") into the ventilation duct 16 through the air inlet 17. Hereinafter, outside air and inside air will be collectively referred to as "air." When the blower 18 is driven, the air sucked in through the air inlet 17 flows through the ventilation duct 16 and is blown out through the multiple outlet openings 13 or the exhaust openings 14.

[0018] Both the first heat exchanger 11 and the second heat exchanger 12 exchange heat between the air passing through the heat exchanger in the ventilation passage 16 (i.e., a substance outside the heat exchanger) and the heat medium flowing inside the heat exchanger. In the following description, the function of radiating heat from the heat medium flowing inside the heat exchanger to a substance outside the heat exchanger is referred to as the "heat radiation function." Also, the function of absorbing heat from a substance outside the heat exchanger into the heat medium flowing inside the heat exchanger is referred to as the "heat absorption function." In this embodiment, the first heat exchanger 11 and the second heat exchanger 12 are configured to be able to arbitrarily switch between the heat radiation function and the heat absorption function by operating the heat medium circuit 2 described below.

[0019] In the ventilation duct 16 of the air conditioning case 10, the first heat exchanger 11 is provided upstream of the second heat exchanger 12. The size of the first heat exchanger 11 is larger than the size of the second heat exchanger 12. Specifically, the volume obtained by multiplying the length, width, and height dimensions of the outer shape of the first heat exchanger 11 is larger than the volume obtained by multiplying the length, width, and height dimensions of the outer shape of the second heat exchanger 12. Furthermore, the air flow path area of ​​the first heat exchanger 11 is larger than the air flow path area of ​​the second heat exchanger 12. Note that the upstream side in the ventilation duct 16 of the air conditioning case 10 refers to the upstream side of the air flow when the air-path switching mechanism 15 is open, and the downstream side in the ventilation duct 16 of the air conditioning case 10 refers to the downstream side of the air flow when the air-path switching mechanism 15 is open.

[0020] In the ventilation passage 16, a first heat exchanger bypass passage 20 is formed between the first heat exchanger 11 and the inner wall of the air conditioning case 10, allowing air drawn in from the air inlet 17 to flow while bypassing the first heat exchanger 11. A cool air bypass passage 21 is formed between the second heat exchanger 12 and the inner wall of the air conditioning case 10, allowing air that has passed through or bypassed the first heat exchanger 11 to flow while bypassing the second heat exchanger 12.

[0021] The plurality of outlet openings 13 are provided downstream of the first heat exchanger 11 and the second heat exchanger 12 in the air conditioning case 10. The plurality of outlet openings 13 are also provided downstream of the cool air bypass passage 21. Air blown from the ventilation passage 16 into the vehicle cabin flows through the outlet openings 13. Specifically, the outlet openings 13 include a defroster outlet opening 131, a face outlet opening 132, a foot outlet opening 133, and a rear passage 134. The defroster outlet opening 131, the face outlet opening 132, and the foot outlet opening 133 are connected to a defroster outlet, a face outlet, and a foot outlet (not shown) provided in the vehicle cabin via ducts (not shown), respectively. Therefore, the defroster outlet opening 131 blows air toward the front windshield of the vehicle. The face outlet opening 132 blows air toward the upper body of the occupant. Air blown toward the lower body of the occupant flows through the foot outlet 133. The rear passage 134 is connected to the space on the rear seat side of the vehicle. Therefore, air blown from the ventilation passage 16 to the space on the rear seat side flows through the rear passage 134.

[0022] The exhaust opening 14 is provided downstream of the first heat exchanger 11 in the air conditioning case 10. In the first embodiment, the exhaust opening 14 is provided in a region of the air conditioning case 10 downstream of the first heat exchanger 11 and upstream of the second heat exchanger 12. The exhaust opening 14 is also provided upstream of the multiple blow-out openings 13. The exhaust opening 14 is connected to a space outside the vehicle cabin. Therefore, air discharged from the ventilation passage 16 to the outside of the vehicle cabin flows through the exhaust opening 14.

[0023] The air passage switching mechanism 15 has a first heat exchanger bypass door 151, a switching door 152, a cold air bypass door 153, a defroster door 154, a face door 155, a foot door 156, and an exhaust door 157. The air passage switching mechanism 15 can switch the air flow path within the ventilation passage 16.

[0024] The first heat exchanger bypass door 151 is a door that opens and closes the first heat exchanger bypass passage 20. The switching door 152 is provided in the ventilation passage 16 between the first heat exchanger 11 and the second heat exchanger 12. As shown in FIG. 5 , the switching door 152, together with the first heat exchanger bypass door 151, can allow air that has bypassed the first heat exchanger 11 to flow to the second heat exchanger 12. As shown in FIG. 1 , the switching door 152 can also allow air that has passed through the first heat exchanger 11 to flow to the second heat exchanger 12. The first heat exchanger bypass door 151 and the switching door 152 may be configured to operate in conjunction with each other, or may be configured to be driven independently.

[0025] The cold air bypass door 153 is a door that opens and closes the cold air bypass passage 21. The defroster door 154 is a door that opens and closes the defroster outlet 131. The face door 155 is a door that opens and closes the face outlet 132. The foot door 156 is a door that opens and closes the foot outlet 133. The exhaust door 157 is a door that opens and closes the exhaust outlet 14.

[0026] 1 and 3A, the air-path switching mechanism 15 can cause air drawn in through the air inlet 17 to flow through both the first heat exchanger 11 and the second heat exchanger 12 to the outlet opening 13. Furthermore, as shown in FIGS. 5 and 7, the air-path switching mechanism 15 can cause a portion of the air drawn in through the air inlet 17 to flow through the first heat exchanger 11 and to the outlet opening 14 without passing through the second heat exchanger 12. At the same time, the air-path switching mechanism 15 can cause another portion of the air drawn in through the air inlet 17 to flow through the first heat exchanger bypass passage 20, then through the second heat exchanger 12, to the outlet opening 13 without passing through the first heat exchanger 11.

[0027] 9 and 11 , the air-path switching mechanism 15 can cause a portion of the air drawn in through the air inlet 17 to flow through the first heat exchanger 11 and to the outlet opening 13 without passing through the second heat exchanger 12. At the same time, the air-path switching mechanism 15 can cause another portion of the air drawn in through the air inlet 17 to flow through the first heat exchanger bypass passage 20 and then through the second heat exchanger 12 to the outlet opening 13 without passing through the first heat exchanger 11.

[0028] 13 , the air-path switching mechanism 15 can cause a portion of the air drawn in through the air inlet 17 to flow through the first heat exchanger 11 and to the exhaust opening 14 without passing through the second heat exchanger 12. At the same time, the air-path switching mechanism 15 can cause another portion of the air drawn in through the air inlet 17 to flow through the first heat exchanger bypass passage 20, the second heat exchanger 12, and then to the exhaust opening 14 without passing through the first heat exchanger 11. Although not shown, by opening the switching door 152 from the state shown in FIG. 13 , the air-path switching mechanism 15 can cause the air flowing through the ventilation passage 16 to flow through both the first heat exchanger 11 and the second heat exchanger 12 and to the exhaust opening 14.

[0029] The door of the air passage switching mechanism 15 is not limited to the plate door shown in each figure, but various doors such as a slide door, a rotary door, or a film door can be used.

[0030] <Configuration of Heat Medium Circuit 2> Next, a description will be given of the configuration of the heat medium circuit 2. Note that the heat medium circuit 2 described below is an example of the present disclosure, and does not limit the present disclosure.

[0031] As shown in Fig. 2, the heat medium circuit 2 is configured by connecting a first heat exchanger 11, a second heat exchanger 12, an external heat exchanger 23, and a heat-generating component heat exchanger 24, etc., with piping through which a heat medium flows. The external heat exchanger 23 is a heat exchanger that exchanges heat between outside air and the heat medium and is provided in a space outside the air conditioning case 10, for example, in an engine compartment or a driving motor compartment of the vehicle. The heat-generating component heat exchanger 24 is a heat exchanger that exchanges heat between the heat medium and a heat-generating component of the vehicle, such as a battery or inverter, mounted on the vehicle (i.e., a substance outside the heat exchanger). The heat-generating component heat exchanger 24 may be configured to exchange heat directly with the heat-generating component of the vehicle, or may be configured to exchange heat with the heat-generating component of the vehicle via a predetermined heat medium.

[0032] The heat medium circuit 2 of this embodiment includes a refrigeration cycle 30 through which a refrigerant flows as a first heat medium, and a coolant circuit 40 through which a coolant flows as a second heat medium. The refrigerant circulating through the refrigeration cycle 30 may be, for example, an HFC refrigerant (e.g., R134a), an HFO refrigerant (e.g., R1234yf), or a natural refrigerant (e.g., carbon dioxide). The coolant circulating through the coolant circuit 40 may be, for example, water or LLC. LLC stands for Long Life Coolant.

[0033] The refrigeration cycle 30 is a vapor compression system in which a compressor 31, a condenser 32, an expansion valve 33, an evaporator 34, and an accumulator 35 are connected in this order in a circular arrangement by refrigerant piping. The compressor 31 compresses gas-phase refrigerant drawn in through a refrigerant suction port and discharges high-temperature, high-pressure refrigerant from a refrigerant discharge port. The refrigerant discharged from the compressor 31 flows into the condenser 32. The condenser 32 is a heat exchanger (specifically, a water-cooled condenser) that exchanges heat between the refrigerant flowing through a coolant circuit 40 and the refrigerant to heat the refrigerant and condense the refrigerant. The expansion valve 33 reduces the pressure of the refrigerant supplied from the condenser 32 and expands it into a low-temperature, low-pressure, gas-liquid two-phase refrigerant, which is then supplied to the evaporator 34. The evaporator 34 is a heat exchanger (specifically, a chiller) that exchanges heat between the refrigerant flowing through the coolant circuit 40 and the refrigerant to cool the refrigerant and evaporate the refrigerant.

[0034] The coolant circuit 40 is a circuit in which the condenser 32, the evaporator 34, the first heat exchanger 11, the second heat exchanger 12, the external heat exchanger 23, the heat exchanger for heat-generating components 24, a plurality of pumps 41, 42, a plurality of flow rate control valves 43, 44, and a plurality of flow path switching valves 45 to 56 are connected by coolant piping. Hereinafter, the coolant piping will be simply referred to as "piping." In this embodiment, the first heat exchanger 11, the second heat exchanger 12, the external heat exchanger 23, and the heat exchanger for heat-generating components 24 are provided in the coolant circuit 40.

[0035] The multiple pumps are composed of a first pump 41 and a second pump 42, and adjust the flow rate of the coolant flowing through the circuit. The first pump 41 is disposed in the piping on the evaporator 34 side, and the second pump 42 is disposed in the piping on the condenser 32 side. In this embodiment, the pumps 41 and 42 are water pumps.

[0036] The plurality of flow rate adjustment valves are composed of a first flow rate adjustment valve 43 and a second flow rate adjustment valve 44, and are capable of adjusting the flow rate of the coolant flowing through the circuit and also capable of blocking the flow of the coolant. The first flow rate adjustment valve 43 is provided in the pipe connecting the pipe on the evaporator 34 side and the pipe on the condenser 32 side. The second flow rate adjustment valve 44 is provided in the pipe upstream of the second heat exchanger 12.

[0037] The plurality of flow path switching valves 45 to 56 switch the flow of the coolant. Note that, although the present embodiment shows an example in which three-way valves are used as the plurality of flow path switching valves 45 to 56, this is not limiting and a multi-way valve of four or more ways may also be used. Furthermore, the installation locations and piping arrangement of the plurality of pumps 41, 42, the plurality of flow rate adjustment valves 43, 44, and the plurality of flow path switching valves 45 to 56 can also be set arbitrarily.

[0038] The ECU 3 is mainly composed of a microcomputer equipped with a processor such as a CPU and memories such as ROM, RAM, and flash memory. The processor of the ECU 3 executes programs stored in the memory, and controls the operation of the compressor 31 of the refrigeration cycle 30, the multiple pumps 41, 42 of the coolant circuit 40, the multiple flow path switching valves 45-56, the multiple flow rate adjustment valves 43, 44, etc. The ECU 3 also controls the operation of the blower 18 and the air path switching mechanism 15 of the air conditioner 1.

[0039] <Operation Modes of Vehicle Heat Pump System> Next, a plurality of operation modes of the vehicle heat pump system executed by the ECU 3 of this embodiment will be described.

[0040] In each drawing, heat exchangers with a heat dissipation function are marked with dots, and heat exchangers with a heat absorption function are marked with cross-hatching. In each drawing showing a heat medium circuit, the flow direction of a high-temperature heat medium is indicated by a dashed arrow, and the flow direction of a low-temperature heat medium is indicated by a solid arrow.

[0041] In the following description, the coolant is not limited to water, but for convenience of explanation, high-temperature coolant will be referred to as "hot water" and low-temperature coolant will be referred to as "cold water."

[0042] <Cooling Mode> The cooling mode will now be described. As shown in Fig. 1, when the cooling mode is executed, the ECU 3 drives the first heat exchanger bypass door 151 to close the first heat exchanger bypass passage 20 and drives the cool air bypass door 153 to open the cool air bypass passage 21. The ECU 3 drives the switching door 152 to allow air to flow from the first heat exchanger 11 to the second heat exchanger 12. The ECU 3 also drives the exhaust door 157 to close the exhaust opening 14.

[0043] The ECU 3 then drives the compressor 31 and closes the first flow control valve 43 and the second flow control valve 44, driving the multiple flow path switching valves 45-56 so that hot water and cold water flow as indicated by the dashed and solid arrows in FIG. 2 . The coolant flowing through the coolant circuit 40 becomes hot water when passing through the condenser 32 and cold water when passing through the evaporator 34. As a result, cold water flows through the first heat exchanger 11, the flow of coolant through the second heat exchanger 12 is blocked, and hot water flows through the external heat exchanger 23. Therefore, the first heat exchanger 11 performs a heat absorption function, the second heat exchanger 12 stops functioning, and the external heat exchanger 23 performs a heat radiation function. Furthermore, cold water flows through the heat exchanger 24 for heat-generating components, and the heat exchanger 24 performs a heat absorption function.

[0044] 1, the air that has passed through both the first heat exchanger 11 and the second heat exchanger 12 is blown into the vehicle cabin from the outlet openings 13 (specifically, the face outlet openings 132 and the rear passage 134). At this time, the cool air generated by passing through the first heat exchanger 11 can pass through both the cool air bypass passage 21 and the second heat exchanger 12, which reduces the pressure loss of the air flowing through the ventilation passage 16, increases the air volume, and enables maximum cooling of the vehicle cabin.

[0045] <Dehumidifying and Heating Mode> The dehumidifying and heating mode will now be described. As shown in Fig. 3A, when the dehumidifying and heating mode is executed, the ECU 3 drives the first heat exchanger bypass door 151 to close the first heat exchanger bypass passage 20 and drives the cool air bypass door 153 to close the cool air bypass passage 21. The ECU 3 drives the switching door 152 to allow air to flow from the first heat exchanger 11 to the second heat exchanger 12. The ECU 3 also drives the exhaust door 157 to close the exhaust opening 14.

[0046] The ECU 3 then drives the compressor 31, drives the multiple flow path switching valves 45-56, and closes the first flow control valve 43 so that hot water and cold water flow as indicated by the dashed and solid arrows in FIG. 3B. Furthermore, the ECU 3 adjusts the opening of the second flow control valve 44 to adjust the flow rate of hot water flowing to the second heat exchanger 12 as indicated by the two-dot chain arrow in FIG. 3B. As a result, cold water flows to the first heat exchanger 11, hot water flows to the second heat exchanger 12, and hot water flows to the external heat exchanger 23. Therefore, the first heat exchanger 11 has a heat absorption function, the second heat exchanger 12 has a heat release function, and the external heat exchanger 23 has a heat release function. Furthermore, cold water flows to the heat exchanger 24 for heat-generating components, and the heat exchanger 24 has a heat absorption function. The dehumidifying and heating mode shown in FIG. 3B is primarily operable from spring to summer because the external heat exchanger 23 functions as a heat release function.

[0047] In contrast, mainly from autumn to winter, a dehumidifying heating mode can be implemented, with the external heat exchanger 23 performing a heat absorption function, as shown in FIG. 4 . The ECU 3 drives the compressor 31 and opens the first flow control valve 43 and the second flow control valve 44 to allow hot water and cold water to flow as indicated by the dashed and solid arrows in FIG. 4 . This causes cold water to flow through the first heat exchanger 11, hot water to flow through the second heat exchanger 12, and cold water to flow through the external heat exchanger 23. Therefore, the first heat exchanger 11 performs a heat absorption function, the second heat exchanger 12 performs a heat release function, and the external heat exchanger 23 performs a heat absorption function. Furthermore, hot water flows through the heat exchanger 24 for heat-generating components, which performs a heat release function.

[0048] 3A , the air that has passed through both the first heat exchanger 11 and the second heat exchanger 12 is blown into the vehicle cabin from the plurality of outlet openings 13. In this case, the maximum heating of the vehicle cabin is possible by maximizing the flow rate of hot water flowing to the second heat exchanger 12 by adjusting the opening degree of the second flow control valve 44. Furthermore, the temperature of the hot air blown into the vehicle cabin can be adjusted by adjusting the flow rate of hot water flowing to the second heat exchanger 12 by adjusting the opening degree of the second flow control valve 44.

[0049] <Maximum Cooling Mode> The maximum cooling mode will now be described. As shown in FIG. 5 , when the maximum cooling mode is executed, the ECU 3 drives the first heat exchanger bypass door 151 and the switching door 152. By driving the first heat exchanger bypass door 151 and the switching door 152, the ECU 3 prohibits air that has passed through the first heat exchanger 11 from flowing to the second heat exchanger 12 and allows air that has passed through the first heat exchanger bypass passage 20 to flow to the second heat exchanger 12. The ECU 3 also drives the cool air bypass door 153 to close the cool air bypass passage 21 and drives the exhaust door 157 to open the exhaust opening 14. The ECU 3 also opens a door (e.g., face door 155) of the air outlet opening 13. As a result, air that has passed through the first heat exchanger 11 but not the second heat exchanger 12 is exhausted to the outside of the vehicle cabin through the exhaust opening 14. In addition, the air that passes through the second heat exchanger 12 but does not pass through the first heat exchanger 11 is blown out from the blow-out opening 13 into the vehicle compartment.

[0050] The ECU 3 then drives the compressor 31 and opens the first flow control valve 43 and the second flow control valve 44, driving the compressor 31 and the multiple flow path switching valves 45-56 so that hot water and cold water flow as indicated by the dashed and solid arrows in Figure 6. As a result, hot water flows through the first heat exchanger 11, cold water flows through the second heat exchanger 12, and hot water flows through the external heat exchanger 23. Therefore, the first heat exchanger 11 has a heat dissipation function, the second heat exchanger 12 has a heat absorption function, and the external heat exchanger 23 has a heat dissipation function. Also, cold water flows through the heat exchanger 24 for heat-generating components, and the heat exchanger 24 has a heat absorption function.

[0051] As a result, the air passing through the first heat exchanger 11 is discharged outside the vehicle cabin through the exhaust opening 14, so that the first heat exchanger 11 functions as a radiator like the external heat exchanger 23, increasing the heat dissipation capacity of the heat medium circuit 2. This increases the cooling capacity of the heat-generating component heat exchanger 24 for the vehicle's heat-generating components, allowing for maximum cooling of the vehicle's heat-generating components. Furthermore, the second heat exchanger 12 can simultaneously cool the vehicle cabin by using a heat absorption function. In this case, neither the first heat exchanger 11 nor the second heat exchanger 12 reheats cooled air and discharges it outside the vehicle, or recools heated air and discharges it outside the vehicle, as in Patent Document 1, so no unnecessary energy loss occurs in the heat medium circuit 2.

[0052] In this embodiment, the size of the first heat exchanger 11 is larger than the size of the second heat exchanger 12. This increases the heat dissipation capacity of the first heat exchanger 11, and therefore increases the cooling capacity of the heat-generating component heat exchanger 24 for the vehicle heat-generating components.

[0053] <Maximum Heating Mode> The maximum heating mode will now be described. As shown in Fig. 7 , when the maximum heating mode is executed, the ECU 3 opens each door (e.g., the defroster door 154, the face door 155, and the foot door 156) of the air outlet opening 13, in contrast to the maximum cooling mode described above. As a result, air that passes through the second heat exchanger 12 but does not pass through the first heat exchanger 11 is blown into the vehicle compartment from each air outlet opening 13. Also, in the maximum heating mode, as in the maximum cooling mode, air that passes through the first heat exchanger 11 but does not pass through the second heat exchanger 12 is discharged to the outside of the vehicle compartment from the exhaust opening 14.

[0054] The state of the heat medium circuit 2 in maximum heating mode is the same as that shown in Figure 4. That is, the ECU 3 drives the compressor 31 and drives the multiple flow path switching valves 45-56 to open the first flow control valve 43 and the second flow control valve 44 so that hot water and cold water flow as indicated by the dashed and solid arrows in Figure 4. As a result, cold water flows through the first heat exchanger 11, hot water flows through the second heat exchanger 12, and cold water flows through the external heat exchanger 23. Therefore, the first heat exchanger 11 has a heat absorption function, the second heat exchanger 12 has a heat release function, and the external heat exchanger 23 has a heat absorption function. In addition, hot water flows through the heat exchanger 24 for heat-generating components, and the heat exchanger 24 has a heat release function.

[0055] As a result, the air passing through the first heat exchanger 11 is discharged to the outside of the vehicle cabin through the exhaust opening 14, so that the first heat exchanger 11 functions as a heat absorber like the external heat exchanger 23, increasing the heat absorption capacity of the heat transfer medium circuit 2. This increases the heat dissipation capacity (i.e., heating capacity) of the heat-generating component heat exchanger 24 to the vehicle's heat-generating components, enabling maximum heating (e.g., warming up) of the vehicle's heat-generating components. Furthermore, the second heat exchanger 12 can simultaneously heat the vehicle cabin by using the heat dissipation function. Again, neither the first heat exchanger 11 nor the second heat exchanger 12 reheats cooled air and discharges it to the outside of the vehicle, as in Patent Document 1, so no unnecessary energy loss occurs in the heat transfer medium circuit 2.

[0056] In this embodiment, the size of the first heat exchanger 11 is larger than the size of the second heat exchanger 12. This increases the heat absorption capacity of the first heat exchanger 11, and increases the heating capacity of the heat-generating component heat exchanger 24 for the vehicle heat-generating components.

[0057] <Switching from Maximum Cooling Mode to Cooling Mode> The control executed by the ECU 3 when switching from maximum cooling mode to cooling mode will be described. As shown in FIG. 8 , when switching from maximum cooling mode to cooling mode, the ECU 3 temporarily blocks the flow of hot water through the first heat exchanger 11 in maximum cooling mode. Specifically, the ECU 3 closes the first flow control valve 43 and the second flow control valve 44. The ECU 3 then drives the flow path switching valves 45-56 to switch to the low-temperature heat medium flow in the cooling mode shown in FIG. 2 . After the temperature of the first heat exchanger 11 becomes lower than the air temperature upstream of the first heat exchanger 11, the ECU 3 drives the air path switching mechanism 15 to enter the cooling mode shown in FIG. 1 . Note that the cooling mode refers to a state in which air that has passed through both the first heat exchanger 11 and the second heat exchanger 12 flows into the air outlet 13. This prevents high-temperature air from being blown into the vehicle cabin through the air outlet 13.

[0058] The vehicle heat pump system of the first embodiment described above provides the following advantages.

[0059] (1) In the first embodiment, when the maximum cooling mode is executed, the ECU 3 drives the components of the heat medium circuit 2 so that the first heat exchanger 11 performs a heat radiation function, the second heat exchanger 12 performs a heat absorption function, and the external heat exchanger 23 performs a heat radiation function, as shown in Figures 5 and 6. The ECU 3 then drives the air path switching mechanism 15 so that air that passes through the first heat exchanger 11 but does not pass through the second heat exchanger 12 is discharged to the outside of the vehicle compartment through the exhaust opening 14, and air that passes through the second heat exchanger 12 but does not pass through the first heat exchanger 11 is blown into the vehicle compartment through the outlet opening 13. By setting the first heat exchanger 11 and the external heat exchanger 23 to the heat radiation function, it is possible to increase the amount of heat dissipated from the heat medium in the heat medium circuit 2 to external substances (i.e., the air discharged to the outside of the vehicle compartment from the air conditioning case 10 and the outside air). Therefore, the second heat exchanger 12 supplies cool air to the vehicle cabin to cool it, while improving the maximum performance of the vehicle heat pump system. At this time, the vehicle heat pump system discharges air that passes through the first heat exchanger 11 but not the second heat exchanger 12 to the outside of the vehicle cabin through the exhaust opening 14. That is, this vehicle heat pump system does not perform the process of cooling air in one heat exchanger and then heating it in the other heat exchanger, as in Patent Document 1, and therefore does not generate energy loss. Therefore, the vehicle heat pump system can improve efficiency compared to the configuration of Patent Document 1.

[0060] (2) In the first embodiment, when the maximum heating mode is executed, the ECU 3 drives the components of the heat medium circuit 2 so that the first heat exchanger 11 performs a heat absorption function, the second heat exchanger 12 performs a heat radiation function, and the external heat exchanger 23 performs a heat absorption function, as shown in Figs. 7 and 4. The ECU 3 then drives the air path switching mechanism 15 so that air that passes through the first heat exchanger 11 but does not pass through the second heat exchanger 12 is discharged to the outside of the vehicle compartment through the exhaust opening 14, and air that passes through the second heat exchanger 12 but does not pass through the first heat exchanger 11 is blown into the vehicle compartment through the outlet opening 13. By setting the first heat exchanger 11 and the external heat exchanger 23 to perform a heat absorption function, it is possible to increase the amount of heat absorbed by the heat medium flowing through the heat medium circuit 2 from the air discharged to the outside of the vehicle compartment from the air conditioning case 10 and the outside air. Therefore, the second heat exchanger 12 supplies warm air to the vehicle cabin to heat it, while improving the maximum performance of the vehicle heat pump system. At this time, the vehicle heat pump system discharges air that passes through the first heat exchanger 11 but not the second heat exchanger 12 to the outside of the vehicle cabin through the exhaust opening 14. That is, this vehicle heat pump system does not perform the process of cooling air in one heat exchanger and then heating it in the other heat exchanger, as in Patent Document 1, and therefore does not generate energy loss. Therefore, the vehicle heat pump system can improve efficiency compared to the configuration of Patent Document 1.

[0061] (3) In the first embodiment, the heat medium circuit 2 is configured so that both the first heat exchanger 11 and the second heat exchanger 12 can be switched between a heat radiation function and a heat absorption function. By switching the functions of the first heat exchanger 11 and the second heat exchanger 12, the air conditioner 1 can operate in the maximum cooling mode and the maximum heating mode with the same configuration.

[0062] (4) In the first embodiment, when switching from the maximum cooling mode to the cooling mode, the ECU 3 blocks the flow of hot water through the first heat exchanger 11 in the maximum cooling mode and switches to the flow of cold water in the cooling mode. After the temperature of the first heat exchanger 11 becomes lower than the temperature of the air upstream of the first heat exchanger 11, the ECU 3 drives the air path switching mechanism 15 to cause air that has passed through both the first heat exchanger 11 and the second heat exchanger 12 to flow to the outlet opening 13. This prevents hot air from being blown into the vehicle cabin through the outlet opening 13 when switching from the maximum cooling mode to the cooling mode.

[0063] (5) In the first embodiment, the volume obtained by multiplying the length, width, and height dimensions of the outer shape of one of the first heat exchanger 11 and the second heat exchanger 12 is larger than the volume obtained by multiplying the length, width, and height dimensions of the outer shape of the other of the first heat exchanger 11 and the second heat exchanger 12. This allows the vehicle heat pump system to increase the heat dissipation capacity of the first heat exchanger 11 in the maximum cooling mode, thereby improving maximum performance. Also, the vehicle heat pump system can increase the heat absorption capacity of the first heat exchanger 11 in the maximum heating mode, thereby improving maximum performance.

[0064] (6) In the first embodiment, the exhaust opening 14 is provided in a region downstream of the first heat exchanger 11 and upstream of the second heat exchanger 12. This effectively utilizes the space between the first heat exchanger 11 and the second heat exchanger 12, thereby reducing the size of the air conditioner 1. In particular, this can further reduce the size of a reheat type air conditioner 1 such as that of this embodiment.

[0065] (7) In the first embodiment, the heat medium circuit 2 includes the second flow rate adjustment valve 44 that can adjust the flow rate or temperature of the heat medium flowing inside the second heat exchanger 12. This makes it possible to adjust the temperature of the conditioned air that passes through the second heat exchanger 12 and is blown into the vehicle cabin through the outlet opening 13.

[0066] (8) In the first embodiment, the heat medium circuit 2 includes a refrigeration cycle 30 through which a refrigerant flows as a first heat medium, and a coolant circuit 40 through which a coolant flows as a second heat medium. The first heat exchanger 11, the second heat exchanger 12, and the external heat exchanger 23 are provided in the coolant circuit 40. This simplifies the configuration of the refrigeration cycle 30.

[0067] (9) When the maximum cooling mode is executed, the ECU 3 drives the components of the heat medium circuit 2 so that the first heat exchanger 11 performs a heat radiation function, the second heat exchanger 12 performs a heat absorption function, the external heat exchanger 23 performs a heat radiation function, and the heat-generating component heat exchanger 24 performs a heat absorption function, as shown in Figures 5 and 6. This allows the vehicle heat pump system to supply cool air to the vehicle interior to cool it, while increasing the cooling capacity of the heat-generating component heat exchanger 24 for the vehicle heat-generating components, i.e., improving maximum performance. Therefore, this vehicle heat pump system can improve the cooling efficiency of the vehicle interior air conditioning and the cooling efficiency of the vehicle heat-generating components compared to the configuration of Patent Document 1.

[0068] (10) When the maximum heating mode is executed, the ECU 3 drives the components of the heat medium circuit 2 so that the first heat exchanger 11 performs a heat absorption function, the second heat exchanger 12 performs a heat radiation function, the external heat exchanger 23 performs a heat absorption function, and the heat-generating component heat exchanger 24 performs a heat radiation function, as shown in Figures 7 and 4. This allows the vehicle heat pump system to supply warm air to the vehicle interior to heat the interior, while increasing the heating capacity (e.g., heating capacity) of the heat-generating component heat exchanger 24 for the vehicle heat-generating components, i.e., improving maximum performance. Therefore, this vehicle heat pump system can improve the heating efficiency of the vehicle interior air conditioning and the heating efficiency of the vehicle heat-generating components compared to the configuration of Patent Document 1.

[0069] Second Embodiment A second embodiment will be described. The second embodiment is the same as the first embodiment except that the cooling mode method is changed from the first embodiment. Therefore, only the differences from the first embodiment will be described.

[0070] <Cooling Mode of Second Embodiment> A description will be given of the cooling mode of the second embodiment. As shown in Fig. 9 and Fig. 10 , in the second embodiment, in the cooling mode, both the first heat exchanger 11 and the second heat exchanger 12 are set to have a heat absorption function.

[0071] Specifically, when the cooling mode is executed, the ECU 3 drives the first heat exchanger bypass door 151 to open the first heat exchanger bypass passage 20 and drives the cool air bypass door 153 to open the cool air bypass passage 21, as shown in FIG. 9 . The ECU 3 may set the switching door 152 to a state that blocks airflow from the first heat exchanger 11 to the second heat exchanger 12, as shown in FIG. 9 , or may set the switching door 152 to a state that allows airflow from the first heat exchanger 11 to the second heat exchanger 12, although not shown. The ECU 3 drives the exhaust door 157 to close the exhaust opening 14. The ECU 3 opens a door (e.g., face door 155) of the air outlet opening 13. As a result, both the air that has passed through the first heat exchanger 11 and the air that has passed through the second heat exchanger 12 are blown into the vehicle cabin through the air outlet opening 13.

[0072] The ECU 3 then drives the compressor 31, drives the multiple flow path switching valves 45-56, and closes the first flow control valve 43 and opens the second flow control valve 44 so that hot water and cold water flow as indicated by the dashed and solid arrows in Figure 10. As a result, cold water flows through both the first heat exchanger 11 and the second heat exchanger 12, and hot water flows through the external heat exchanger 23. Therefore, the first heat exchanger 11 and the second heat exchanger 12 have a heat absorption function, and the external heat exchanger 23 has a heat radiation function. Furthermore, cold water flows through the heat exchanger for heat-generating components 24, and the heat exchanger for heat-generating components 24 has a heat absorption function.

[0073] In the second embodiment described above, the ECU 3 can drive the heat medium circuit 2 so that both the first heat exchanger 11 and the second heat exchanger 12 are in the heat absorption function. By doing so, the cooling capacity of the vehicle interior can be increased by using both the first heat exchanger 11 and the second heat exchanger 12 in the heat absorption function. Alternatively, if the cooling capacity when using both the first heat exchanger 11 and the second heat exchanger 12 is equivalent to the cooling capacity when using only the first heat exchanger 11 as described in the cooling mode of the first embodiment, the configuration of the second embodiment can reduce the size of the first heat exchanger 11 and the second heat exchanger 12. Therefore, the configuration of the second embodiment can reduce the size of the air conditioner 1.

[0074] Third Embodiment A third embodiment will be described. The third embodiment is similar to the first embodiment except for the method of the heating mode, and therefore only the differences from the first embodiment will be described.

[0075] <Heating Mode of Third Embodiment> A description will be given of the heating mode of the third embodiment. As shown in Fig. 11 and Fig. 12 , in the heating mode of the third embodiment, both the first heat exchanger 11 and the second heat exchanger 12 are set to the heat radiation function.

[0076] 11 , when the ECU 3 executes the heating mode, it opens the doors (e.g., the defroster door 154, the face door 155, and the foot door 156) of the air outlet opening 13, in contrast to the cooling mode described in the second embodiment. As a result, both the air that has passed through the first heat exchanger 11 and the air that has passed through the second heat exchanger 12 are blown out from the air outlet opening 13 into the vehicle compartment.

[0077] The ECU 3 then drives the compressor 31 and drives the multiple flow path switching valves 45-57 to allow hot water and cold water to flow as indicated by the dashed and solid arrows in FIG. 12 , opening the first flow control valve 43 and the second flow control valve 44 and closing the third flow control valve 68. As a result, hot water flows through both the first heat exchanger 11 and the second heat exchanger 12, and cold water flows through the external heat exchanger 23. Therefore, the first heat exchanger 11 and the second heat exchanger 12 have a heat dissipation function, and the external heat exchanger 23 has a heat absorption function. In addition, hot water flows through the heat exchanger for heat-generating components 24, which has a heat dissipation function.

[0078] In the third embodiment described above, the ECU 3 can drive the heat medium circuit 2 to set both the first heat exchanger 11 and the second heat exchanger 12 to the heat dissipation function. By setting both the first heat exchanger 11 and the second heat exchanger 12 to the heat dissipation function, the vehicle interior heating capacity can be increased. Alternatively, if the heating capacity when both the first heat exchanger 11 and the second heat exchanger 12 are used is equivalent to the heating capacity when only the second heat exchanger 12 is used, as described in the heating mode of the first embodiment, the configuration of the third embodiment can reduce the size of the first heat exchanger 11 and the second heat exchanger 12. Therefore, the configuration of the third embodiment can reduce the size of the air conditioning device 1.

[0079] (Fourth embodiment) A fourth embodiment will be described. The fourth embodiment is different from the first embodiment in that the method of operating the maximum cooling mode when no occupants are present is changed, but the rest is the same as the first embodiment, so only the differences from the first embodiment will be described.

[0080] <Maximum Cooling Mode of Fourth Embodiment> The maximum cooling mode of the fourth embodiment will be described. As shown in Figures 13 and 14, in the fourth embodiment, in the maximum cooling mode, both the first heat exchanger 11 and the second heat exchanger 12 are set to the heat dissipation function.

[0081] Specifically, when the maximum cooling mode is executed, the ECU 3 drives the first heat exchanger bypass door 151 to open the first heat exchanger bypass passage 20 and drives the cool air bypass door 153 to open the cool air bypass passage 21, as shown in FIG. 13 . The ECU 3 may set the switching door 152 to a state that blocks airflow from the first heat exchanger 11 to the second heat exchanger 12, as shown in FIG. 13 , or may set the switching door 152 to a state that allows airflow from the first heat exchanger 11 to the second heat exchanger 12, as not shown. The ECU 3 drives the exhaust door 157 to open the exhaust opening 14. The ECU 3 closes the defroster door 154, the face door 155, and the foot door 156, and also closes the rear passage 134 with a door (not shown). Therefore, both the air that has passed through the first heat exchanger 11 and the air that has passed through the second heat exchanger 12 are blown out of the vehicle cabin through the exhaust opening 14.

[0082] The ECU 3 then drives the compressor 31 and the multiple flow path switching valves 45-56 so that hot water and cold water flow as indicated by the dashed and solid arrows in FIG. 14 , opening the first flow control valve 43 and the second flow control valve 44 and closing the third flow control valve 68 and the fourth flow control valve 69. As a result, hot water flows through the first heat exchanger 11, the second heat exchanger 12, and the external heat exchanger 23. Therefore, the first heat exchanger 11, the second heat exchanger 12, and the external heat exchanger 23 perform a heat dissipation function. Meanwhile, cold water flows through the heat exchanger 24 for heat-generating components, and the heat exchanger 24 performs a heat absorption function.

[0083] In the fourth embodiment described above, the ECU 3 drives the heat medium circuit 2 to set all of the first heat exchanger 11, the second heat exchanger 12, and the external heat exchanger 23 to the heat dissipation function. The ECU 3 can then execute a second maximum cooling mode, which drives the air-path switching mechanism 15 to discharge the air that has passed through the first heat exchanger 11 and the air that has passed through the second heat exchanger 12 to the outside of the vehicle cabin through the exhaust opening 14. This increases the cooling capacity of the heat medium circuit 2 for the heat-generating component heat exchanger 24 for the vehicle heat-generating component. This increases the cooling capacity for the battery, an example of a heat-generating component, and shortens the quick charging time when no passengers are present. Furthermore, drying the first heat exchanger 11 and the second heat exchanger 23 can suppress the adhesion of bacteria to the heat exchangers.

[0084] Fifth Embodiment A fifth embodiment will be described. The fifth embodiment, unlike the first embodiment, relates to a method for heating and a heating mode when frost or the like has adhered to the external heat exchanger 23. Since the other aspects are the same as those of the first embodiment, only the differences from the first embodiment will be described.

[0085] The fifth embodiment will be described with reference to FIGS.

[0086] <Heating and Heating Modes in Case of Frost or the like on the External Heat Exchanger 23> The heating and heating modes in a case where frost or the like has formed on the external heat exchanger 23, making it difficult for the external heat exchanger 23 to absorb heat from the outside air, will be described. In this case, as shown in FIG. 22 , the ECU 3 drives the air-path switching mechanism 15 in the same manner as in the maximum heating mode described with reference to FIG. 7 of the first embodiment. Therefore, air that passes through the first heat exchanger 11 but does not pass through the second heat exchanger 12 is discharged to the outside of the vehicle compartment through the exhaust openings 14. Furthermore, air that passes through the second heat exchanger 12 but does not pass through the first heat exchanger 11 is blown into the vehicle compartment through the outlet openings 13. Also, as shown in FIG. 23 , an electric heater 70 is provided near the external heat exchanger 23. The electric heater 70 heats the external heat exchanger 23 when energized.

[0087] The ECU 3 then drives the compressor 31 and opens the first flow control valve 43 and the second flow control valve 44, driving the multiple flow path switching valves 45-56 so that hot water and cold water flow as indicated by the dashed and solid arrows in Figure 23. The ECU 3 also drives the flow path switching valve 45, located upstream of the external heat exchanger 23, to block the flow of cold water to the external heat exchanger 23. As a result, cold water flows to the first heat exchanger 11, hot water flows to the second heat exchanger 12, hot water flows to the heat exchanger 24 for the heat-generating component, and no cold water flows to the external heat exchanger 23. Therefore, the first heat exchanger 11 has a heat absorption function, the second heat exchanger 12 and the heat exchanger 24 have a heat release function, and the external heat exchanger 23 is in a state where it is neither absorbing nor releasing heat.

[0088] In the fifth embodiment described above, even if frost or the like accumulates on the external heat exchanger 23, making it difficult to maintain the heat absorption performance from the outside air, it is possible to melt the frost on the external heat exchanger 23 by the electric heater 70. At the same time, in the fifth embodiment, the first heat exchanger 11 enables heat absorption from the air flowing through the ventilation passage 16 to the heat medium, so that it is possible to heat the vehicle interior and heat-generating vehicle components (for example, to warm up the vehicle).

[0089] Sixth Embodiment A sixth embodiment will be described. In the sixth embodiment, the configuration of the air conditioner 1 and the configuration of the heat medium circuit 2 are partially changed compared to the first to fifth embodiments, but the remaining configuration is the same as the first to fifth embodiments. Therefore, only the differences from the first to fifth embodiments will be described.

[0090] <Configuration of Air Conditioner 1> As shown in Fig. 15 , the air conditioner 1 of the sixth embodiment is an air-mix type. An air-mix region 25 is provided inside the air-conditioning case 10 in an area downstream of the cool air bypass passage 21 and upstream of each of the blow-out openings 13. Note that in Fig. 15 , the air-mix region 25 is shown with a dashed line for the sake of explanation, but the air-mix region 25 and other areas are a continuous space. In the sixth embodiment, the exhaust opening 14 and the multiple blow-out openings 13 are provided downstream of the air-mix region 25 in the air-conditioning case 10. A partition wall 26 is provided between the exhaust opening 14 and the multiple blow-out openings 13.

[0091] The air passage switching mechanism 15 includes a first heat exchanger bypass door 151, an air mix door 158, a partition door 159, an exhaust door 157, a defroster door 154, a face door 155, a foot door 156, and the like.

[0092] As shown in FIG. 15 , the air mix door 158 allows air that has passed through the first heat exchanger 11 to flow to the outlet opening 13 without passing through the second heat exchanger 12, and allows air that has bypassed the first heat exchanger 11 and flowed through the first heat exchanger bypass passage 20 to flow to the second heat exchanger 12. Although not shown, the air mix door 158 can also allow air that has passed through the first heat exchanger 11 to pass through the second heat exchanger 12. Furthermore, by adjusting the opening degree of the air mix door 158, it is possible to adjust the amount of air that passes through the first heat exchanger 11 and bypasses the second heat exchanger 12, and the amount of air that passes through both the first heat exchanger 11 and the second heat exchanger 12. The partition door 159 can allow or prohibit air that has passed through the second heat exchanger 12 from flowing into the air mix region 25.

[0093] The door of the air passage switching mechanism 15 is not limited to the plate door shown in each figure, but various doors such as a slide door, a rotary door, or a film door can be used.

[0094] <Configuration of Heat Medium Circuit 2> Next, the configuration of the heat medium circuit 2 of the sixth embodiment will be described. In the sixth embodiment, the first heat exchanger 11 is described as having a heat absorption function, and the second heat exchanger 12 is described as having a heat release function. Note that the heat medium circuit 2 described below is also an example of the present disclosure, and is not intended to limit the present disclosure.

[0095] As shown in FIG. 16, the heat medium circuit 2 of the sixth embodiment also includes a refrigeration cycle 30 through which a refrigerant flows as a first heat medium, and a coolant circuit 40 through which a coolant flows as a second heat medium.

[0096] The coolant circuit 40 is a circuit in which the condenser 32 and evaporator 34 of the refrigeration cycle 30, the first heat exchanger 11, the second heat exchanger 12, the external heat exchanger 23, the heat exchanger for the heat-generating component 24, multiple pumps 41, 42, and multiple flow path switching valves 58-63 are connected by piping. However, in the sixth embodiment, the first heat exchanger 11 and the second heat exchanger 12 do not switch between a heat absorption function and a heat release function. Instead, the first heat exchanger 11 is fixed to the heat absorption function, and the second heat exchanger 12 is fixed to the heat release function. Therefore, the heat medium circuit 2 of the sixth embodiment has a simpler configuration than the multiple flow path switching valves 45-56 and piping arrangement described in the first embodiment and the like. Specifically, the coolant circuit 40 of the sixth embodiment has fewer flow path switching valves 58-63 than the first embodiment and the like. Furthermore, the coolant circuit 40 of the sixth embodiment does not necessarily include the plurality of flow rate adjustment valves 43, 44 described in the first embodiment and the like.

[0097] <Maximum Cooling Mode> The maximum cooling mode will now be described. As shown in FIG. 15 , when the maximum cooling mode is executed during high outside air temperatures, such as in summer, the ECU 3 drives the air mix door 158 to prohibit air that has passed through the first heat exchanger 11 from flowing into the second heat exchanger 12. The ECU 3 closes the partition door 159 and opens a door (e.g., face door 155) at the outlet opening 13. As a result, air that has passed through the first heat exchanger 11 but not the second heat exchanger 12 is blown into the vehicle cabin from the outlet opening 13. The ECU 3 also drives the first heat exchanger bypass door 151 to allow air that has passed through the first heat exchanger bypass passage 20 to flow into the second heat exchanger 12. The ECU 3 closes the partition door 159 to prohibit air that has passed through the second heat exchanger 12 from flowing into the air mix region 25, and drives the exhaust door 157 to open the exhaust opening 14. Therefore, the air that passes through the second heat exchanger 12 but does not pass through the first heat exchanger 11 is discharged to the outside of the vehicle compartment through the exhaust opening 14 .

[0098] The ECU 3 then drives the compressor 31 and the multiple flow path switching valves 58 to 63 so that hot water and cold water flow as indicated by the dashed and solid arrows in Fig. 16. As a result, cold water flows through the first heat exchanger 11, hot water flows through the second heat exchanger 12 and the external heat exchanger 23, and cold water flows through the heat exchanger for heat-generating components 24. Therefore, the first heat exchanger 11 has a heat absorption function, the second heat exchanger 12 and the external heat exchanger 23 have a heat release function, and the heat exchanger for heat-generating components 24 has a heat absorption function.

[0099] As a result, the air that has passed through the second heat exchanger 12 is discharged outside the vehicle compartment through the exhaust opening 14, so that the second heat exchanger 12 acts as a radiator like the external heat exchanger 23, and it is possible to increase the heat dissipation capacity of the heat medium circuit 2. This increases the cooling capacity of the heat-generating component heat exchanger 24 for the vehicle heat-generating components, enabling maximum cooling of the vehicle heat-generating components. In addition, the first heat exchanger 11 can also be used as a heat absorption function to simultaneously cool the vehicle compartment.

[0100] In the sixth embodiment described above, the first heat exchanger 11 and the second heat exchanger 12 do not switch between a heat absorption function and a heat release function, but are fixed so that the first heat exchanger 11 has a heat absorption function and the second heat exchanger 12 has a heat release function. Therefore, the heat medium circuit 2 of the sixth embodiment can have a simpler configuration than the heat medium circuit 2 described in the first embodiment and the like.

[0101] In the sixth embodiment, neither the first heat exchanger 11 nor the second heat exchanger 12 reheats cooled air and discharges it outside the vehicle, nor recools heated air and discharges it outside the vehicle, as in Patent Document 1. Therefore, no unnecessary energy loss occurs in the heat medium circuit 2.

[0102] Seventh Embodiment A seventh embodiment will be described. The seventh embodiment is different from the sixth embodiment in that the configuration of the air conditioner 1 is partially changed, and the remaining configuration is the same as the sixth embodiment. Therefore, only the differences from the sixth embodiment will be described.

[0103] 17 , the air conditioner 1 of the seventh embodiment is provided with a second exhaust opening 142 and a second exhaust door 1572 in an area of ​​the air conditioning case 10 that is downstream of the first heat exchanger 11 and upstream of the second heat exchanger 12. Also, a cold air bypass door 153 is provided in the cold air bypass passage 21. Note that in the seventh embodiment, the exhaust opening 14 and the exhaust door 157 downstream of the second heat exchanger 12 described in the sixth embodiment are referred to as a first exhaust opening 141 and a first exhaust door 1571, respectively.

[0104] <Maximum Heating Mode> The maximum heating mode will now be described. As shown in FIG. 17 , when the maximum heating mode is executed when the outside temperature is low, such as in winter, the ECU 3 drives the air mix door 158 to prohibit air that has passed through the first heat exchanger 11 from flowing into the second heat exchanger 12. The ECU 3 opens the second exhaust door 1572 and closes the cool air bypass door 153. As a result, air that has passed through the first heat exchanger 11 but not the second heat exchanger 12 is exhausted to the outside of the vehicle cabin through the second exhaust opening 142. The ECU 3 also drives the first heat exchanger bypass door 151 to allow air that has passed through the first heat exchanger bypass passage 20 to flow into the second heat exchanger 12. The ECU 3 closes the first exhaust door 1571 and opens the partition door 159 and the door of the air outlet opening 13. Therefore, the air that does not pass through the first heat exchanger 11 but passes through the first heat exchanger bypass passage 20 and the second heat exchanger 12 is blown out from each outlet opening 13 into the vehicle compartment.

[0105] The ECU 3 then drives the compressor 31 and the multiple flow path switching valves 58 to 63 so that hot water and cold water flow as indicated by the dashed and solid arrows in Fig. 18. As a result, cold water flows through the first heat exchanger 11 and the external heat exchanger 23, and hot water flows through the second heat exchanger 12 and the heat exchanger for heat-generating components 24. Therefore, the first heat exchanger 11 and the external heat exchanger 23 have a heat absorption function, and the second heat exchanger 12 and the heat exchanger for heat-generating components 24 have a heat release function.

[0106] As a result, the air that has passed through the first heat exchanger 11 is discharged to the outside of the vehicle compartment through the second exhaust opening 142, so that the first heat exchanger 11 acts as a heat absorber similar to the external heat exchanger 23, and it is possible to increase the heat absorption capacity of the heat medium circuit 2. As a result, the heating capacity of the heat-generating component heat exchanger 24 for the vehicle heat-generating components is increased, and the vehicle heat-generating components can be heated to the maximum (for example, warmed up).

[0107] Furthermore, the second heat exchanger 12 can simultaneously heat the passenger compartment by using the heat dissipation function. When heating the passenger compartment, the outlet temperature can be adjusted by adjusting the opening degree of the air mix door 158.

[0108] In the seventh embodiment described above, the first heat exchanger 11 and the second heat exchanger 12 do not switch between a heat absorption function and a heat release function, but the first heat exchanger 11 is fixed to the heat absorption function and the second heat exchanger 12 is fixed to the heat release function. Therefore, the heat medium circuit 2 of the seventh embodiment can also have a simpler configuration than the heat medium circuit 2 described in the first embodiment, etc.

[0109] In the seventh embodiment, neither the first heat exchanger 11 nor the second heat exchanger 12 reheats cooled air and discharges it outside the vehicle, nor recools heated air and discharges it outside the vehicle, as in Patent Document 1. Therefore, no unnecessary energy loss occurs in the heat medium circuit 2.

[0110] Eighth Embodiment An eighth embodiment will be described. The eighth embodiment is different from the first to seventh embodiments in the configuration of the heat medium circuit 2, but is otherwise similar to the first to seventh embodiments. Therefore, only the differences from the first to seventh embodiments will be described.

[0111] <Configuration of Heat Medium Circuit 2> The configuration of the heat medium circuit 2 of the eighth embodiment will be described. Note that the heat medium circuit 2 described below is also an example of the present disclosure, and does not limit the present disclosure.

[0112] As shown in Fig. 19 , in the heat medium circuit 2 of the eighth embodiment, a first heat exchanger 11, a second heat exchanger 12, an external heat exchanger 23, and a heat-generating component heat exchanger 24 are provided in the refrigerant piping of a refrigeration cycle 30. In addition to these heat exchangers, the refrigeration cycle 30 is configured to include a compressor 31, an expansion valve 33, a receiver 36, and multiple flow path switching valves 64 to 67 connected by refrigerant piping. The multiple flow path switching valves 64 to 67 are, for example, four-way valves. The first heat exchanger 11, the second heat exchanger 12, the external heat exchanger 23, and the heat-generating component heat exchanger 24 can all be used by switching between a heat release function and a heat absorption function.

[0113] <Maximum Cooling Mode> The maximum cooling mode will now be described. As shown in FIG. 19 , the ECU 3 drives the compressor 31 and drives the multiple flow path switching valves 64 to 67 so that the refrigerant flows as indicated by the dashed and solid arrows in FIG. 19 . Specifically, the high-temperature, high-pressure refrigerant discharged from the compressor 31 flows through the external heat exchanger 23 and the second heat exchanger 12, condenses, and flows into the receiver 36. The refrigerant flowing out of the receiver 36 then passes through the expansion valve 33 to become a low-temperature, low-pressure, gas-liquid two-phase refrigerant, flows through the heat-generating component heat exchanger 24 and the first heat exchanger 11, and becomes a gas-phase refrigerant before being drawn into the compressor 31. Therefore, the low-temperature, low-pressure refrigerant flows through the first heat exchanger 11 and the heat-generating component heat exchanger 24, and the high-temperature, high-pressure refrigerant flows through the second heat exchanger 12 and the external heat exchanger 23. Therefore, the first heat exchanger 11 and the heat exchanger for heat-generating components 24 have a heat absorption function, and the second heat exchanger 12 and the external heat exchanger 23 have a heat dissipation function. As shown in Figure 15, the air conditioning device 1 discharges air that has passed through the second heat exchanger 12 to the outside of the vehicle and supplies air that has passed through the first heat exchanger 11 to the inside of the vehicle. This allows the vehicle's heat-generating components to be cooled and the vehicle interior to be cooled.

[0114] <Maximum Heating Mode> The maximum heating mode will now be described. As shown in FIG. 20 , the ECU 3 drives the compressor 31 and drives the multiple flow path switching valves 64 to 67 so that the refrigerant flows as indicated by the dashed and solid arrows in FIG. 20 . Specifically, the high-temperature, high-pressure refrigerant discharged from the compressor 31 flows through the second heat exchanger 12 and the heat-generating component heat exchanger 24, condenses, and flows into the receiver 36. The refrigerant flowing out of the receiver 36 then passes through the expansion valve 33 to become a low-temperature, low-pressure, gas-liquid two-phase refrigerant, flows through the external heat exchanger 23 and the first heat exchanger 11, and becomes a gas-phase refrigerant before being drawn into the compressor 31. Therefore, the low-temperature, low-pressure refrigerant flows through the first heat exchanger 11 and the external heat exchanger 23, and the high-temperature, high-pressure refrigerant flows through the second heat exchanger 12 and the heat-generating component heat exchanger 24. Therefore, the first heat exchanger 11 and the external heat exchanger 23 have a heat absorption function, and the second heat exchanger 12 and the heat exchanger for heat-generating components 24 have a heat dissipation function. As shown in Figure 17, the air conditioning device 1 discharges air that has passed through the first heat exchanger 11 to the outside of the vehicle and supplies air that has passed through the second heat exchanger 12 into the vehicle compartment. This allows the vehicle's heat-generating components and the vehicle interior to be heated.

[0115] In the heat medium circuit 2 of the eighth embodiment, the functions of the first heat exchanger 11 and the second heat exchanger 12 can be switched by driving two flow path switching valves 65, 66 provided at both ends of the first heat exchanger 11 and the second heat exchanger 12. That is, in the maximum cooling mode, the first heat exchanger 11 can be set to the heat radiation function and the second heat exchanger 12 can be set to the heat absorption function. Also, in the maximum heating mode, the first heat exchanger 11 can be set to the heat absorption function and the second heat exchanger 12 can be set to the heat radiation function.

[0116] Ninth Embodiment A ninth embodiment will be described. The ninth embodiment is similar to the first to eighth embodiments except for the configuration of the heat medium circuit 2, and therefore only the differences from the first to eighth embodiments will be described.

[0117] <Configuration of Heat Medium Circuit 2> The configuration of the heat medium circuit 2 of the ninth embodiment will be described. Note that the heat medium circuit 2 described below is also an example of the present disclosure, and does not limit the present disclosure.

[0118] 21 , in the heat medium circuit 2 of the ninth embodiment, a first heat exchanger 11, a second heat exchanger 12, and an external heat exchanger 23 are provided in the refrigerant piping of the refrigeration cycle 30, and a heat exchanger for heat-generating components 24 is provided in the coolant circuit 40. In addition to the first heat exchanger 11, the second heat exchanger 12, and the external heat exchanger 23, the refrigeration cycle 30 also includes a plurality of “refrigerant-coolant heat exchangers 37 to 39” that exchange heat between the refrigerant flowing through the refrigeration cycle 30 and the coolant flowing through the coolant circuit 40.

[0119] As in the ninth embodiment described above, the first heat exchanger 11, the second heat exchanger 12, and the external heat exchanger 23 can be the condenser 32 or the evaporator 34 included in the refrigeration cycle 30, and the heat exchanger for heat generating components 24 can be the heat exchanger included in the coolant circuit 40. That is, the first heat exchanger 11, the second heat exchanger 12, the external heat exchanger 23, and the heat exchanger for heat generating components 24 can be the heat exchanger included in the coolant circuit 40, or the condenser 32 or the evaporator 34 included in the refrigeration cycle 30.

[0120] (Other Embodiments) (1) In the heat medium circuit 2 described in the first to fifth embodiments, the pipes are connected using three-way valves as flow path switching valves, but this is not limiting, and the pipes may be connected using multi-way valves such as four-way valves, five-way valves, etc. In this case, the pipe configuration can be simplified.

[0121] (2) In the sixth and seventh embodiments, the first heat exchanger 11 has a heat absorption function and the second heat exchanger 12 has a heat radiation function. However, this is not limiting, and for example, the first heat exchanger 11 may have a heat radiation function and the second heat exchanger 12 may have a heat absorption function. Also, in the sixth and seventh embodiments, the heat medium circuit 2 may be configured so that the first heat exchanger 11 and the second heat exchanger 12 can be used by arbitrarily switching between the heat radiation function and the heat absorption function.

[0122] The present disclosure is not limited to the above-described embodiments and can be modified as appropriate. Furthermore, the above-described embodiments and portions thereof are not unrelated to each other and can be combined as appropriate unless the combination is clearly impossible. It goes without saying that, in each of the above embodiments, the elements constituting the embodiments are not necessarily essential unless specifically stated as essential or clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, values, amounts, and ranges of components of the embodiments are mentioned, they are not limited to the specific numbers unless specifically stated as essential or clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shape, positional relationship, etc. of components, etc. are mentioned, they are not limited to the shape, positional relationship, etc., unless specifically stated or limited to a specific shape, positional relationship, etc. in principle.

[0123] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. The memory is a non-transitory tangible storage medium.

[0124] (Aspects of the Present Disclosure) The above-described present disclosure can be understood from the following aspects, for example. [First Aspect] A vehicle heat pump system comprising: an air conditioning case (10) having an air passage (16) through which air drawn in from outside the vehicle compartment and air drawn in from inside the vehicle compartment flow; a first heat exchanger (11) provided in the air passage of the air conditioning case and performing heat exchange between the air flowing in the air passage and a heat medium; a second heat exchanger (12) provided in the air passage of the air conditioning case downstream of the first heat exchanger and performing heat exchange between the air flowing in the air passage and a heat medium; an outlet opening (13) provided in the air conditioning case downstream of the first heat exchanger and the second heat exchanger and through which air blown into the vehicle compartment from the air passage flows; and exhaust openings (14, 141, 142) provided in the air conditioning case downstream of the first heat exchanger and through which air discharged to the outside of the vehicle compartment from the air passage flows. an air-path switching mechanism (15) capable of switching the path of air flow in the ventilation duct between a state in which air flowing through the ventilation duct passes through the first heat exchanger and to the blow-out opening or the exhaust opening without passing through the second heat exchanger, and a state in which air flowing through the ventilation duct passes through the second heat exchanger and to the blow-out opening or the exhaust opening without passing through the first heat exchanger; an external heat exchanger (23) provided in a space outside the air-conditioning case and performing heat exchange between air outside the vehicle cabin and a heat medium; a heat medium circuit (2) connecting the first heat exchanger, the second heat exchanger, and the external heat exchanger with piping through which the heat medium flows, and having flow path switching valves (45 to 67) in the piping for switching the flow of the heat medium; and an electronic control device (3) for controlling the driving of the air-path switching mechanism and each part of the heat medium circuit, The function of radiating heat from the heat medium flowing inside the heat exchanger to a substance outside the heat exchanger is called the heat radiation function, and the function of absorbing heat from a substance outside the heat exchanger to the heat medium flowing inside the heat exchanger is called the heat absorption function.The electronic control device is capable of executing a maximum cooling mode in which the electronic control device drives each part of the heat medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and drives the air path switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not the other is discharged to the outside of the vehicle compartment through the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not the other is blown into the vehicle compartment through the blow-out opening. [Second Aspect] The vehicle heat pump system according to the first aspect, wherein the electronic control device is capable of executing a maximum heating mode in which the electronic control device drives each component of the heat medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat absorption function, the other performs a heat radiation function, and the external heat exchanger performs a heat absorption function, and drives the air path switching mechanism to exhaust air that passes through one of the first heat exchanger and the second heat exchanger but not the other to the outside of the vehicle compartment through the exhaust opening, and blow air that passes through the other of the first heat exchanger and the second heat exchanger but not the one into the vehicle compartment through the blow-out opening. [Third Aspect] The vehicle heat pump system according to the first or second aspect, wherein the heat medium circuit is configured so that both the first heat exchanger and the second heat exchanger can be used by switching between a heat radiation function and a heat absorption function. [Fourth Aspect] The air passage switching mechanism is capable of switching a path through which air flows in the ventilation passage so that the air passing through the ventilation passage passes through both the first heat exchanger and the second heat exchanger and then flows to the outlet opening or the exhaust opening, and the electronic control device is capable of executing a cooling mode in which the electronic control device drives each part of the heat medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat absorption function, the other stops the flow of the heat medium or performs a heat absorption function, and the external heat exchanger performs a heat release function, and drives the air passage switching mechanism so that the air that has passed through both the first heat exchanger and the second heat exchanger is blown into the vehicle compartment through the outlet opening,and a heat pump system for a vehicle according to any one of the first to third aspects, wherein, when switching from the maximum cooling mode to the cooling mode, the electronic control device shuts off the flow of high-temperature heat medium through one of the first heat exchanger and the second heat exchanger in the maximum cooling mode and switches to the flow of low-temperature heat medium in the cooling mode, and drives the airflow path switching mechanism to cause the air that has passed through both the first heat exchanger and the second heat exchanger to flow to the air outlet opening after the temperature of one of the first heat exchanger and the second heat exchanger becomes lower than the temperature of the air upstream of one of the first heat exchanger and the second heat exchanger. [Sixth Aspect] The vehicle heat pump system according to any one of the first to fifth aspects, wherein the exhaust opening is provided in a region downstream of the first heat exchanger and upstream of the second heat exchanger. [Seventh Aspect] The heat medium circuit is configured to switch between a heat radiation function and a heat absorption function for both the first heat exchanger and the second heat exchanger, and the electronic control device is capable of driving the heat medium circuit to set both the first heat exchanger and the second heat exchanger to the heat radiation function and further capable of driving the heat medium circuit to set both the first heat exchanger and the second heat exchanger to the heat absorption function. [Eighth Aspect] The vehicle heat pump system according to any one of the first to seventh aspects, wherein the heat medium circuit includes a flow rate adjustment valve (44) that adjusts the flow rate or temperature of the heat medium flowing through the second heat exchanger. [Ninth Aspect] The vehicle further includes a heat exchanger (24) for heat-generating components mounted on the vehicle for exchanging heat between the heat medium and the heat-generating components, and the heat medium circuit connects the first heat exchanger, the second heat exchanger, the external heat exchanger, and the heat-generating component heat exchanger with the piping through which the heat medium flows,10. The heat pump system for a vehicle according to claim 1, further comprising: a heat exchanger (24) for exchanging heat between a heat medium and a heat-generating component mounted on the vehicle, the heat medium circuit connecting the first heat exchanger, the second heat exchanger, the external heat exchanger and the heat-generating component heat exchanger by piping through which the heat medium flows, and the electronic control device is configured to drive each part of the heat medium circuit so that, when the maximum cooling mode is executed, one of the first heat exchanger and the second heat exchanger performs a heat release function, the other performs a heat absorption function, the external heat exchanger performs a heat release function, and the heat-generating component heat exchanger performs a heat absorption function. [Tenth Aspect] The heat pump system for a vehicle according to the second aspect, further comprising: a heat exchanger (24) for exchanging heat between a heat-generating component mounted on the vehicle and the heat medium, the heat medium circuit connecting the first heat exchanger, the second heat exchanger, the external heat exchanger and the heat-generating component heat exchanger by piping through which the heat medium flows, and the electronic control device is configured to drive each part of the heat medium circuit so that, when the maximum heating mode is executed, one of the first heat exchanger and the second heat exchanger performs a heat absorption function, the other performs a heat release function, the external heat exchanger performs a heat absorption function, and the heat-generating component heat exchanger performs a heat release function. [Eleventh Aspect] The vehicle heat pump system according to any one of the first to tenth aspects, wherein the heat medium circuit includes a refrigeration cycle (30) through which a refrigerant flows as a first heat medium, and a coolant circuit (40) through which a coolant flows as a second heat medium, the refrigeration cycle includes a compressor (31) that compresses and discharges the refrigerant, a condenser (32) that heats the coolant and condenses the refrigerant by heat exchange between the coolant flowing in the coolant circuit and the refrigerant, an expansion valve (33) that decompresses and expands the refrigerant condensed in the condenser, and an evaporator (34) that cools the coolant and evaporates the refrigerant by heat exchange between the coolant flowing in the coolant circuit and the refrigerant, and the first heat exchanger, the second heat exchanger, and the external heat exchanger are heat exchangers included in the coolant circuit. [Twelfth Aspect] The heat medium circuit includes a refrigeration cycle through which a refrigerant flows as a heat medium, the refrigeration cycle including a compressor that compresses and discharges the refrigerant, a condenser that heats air by heat exchange between the air and the refrigerant and condenses the refrigerant, an expansion valve that reduces the pressure and expands the refrigerant condensed in the condenser, an evaporator that cools air by heat exchange between the air and the refrigerant and evaporates the refrigerant, and the flow path switching valve (64 to 67) that switches the flow of the refrigerant midway through the piping,The vehicle heat pump system according to any one of the first to tenth aspects, wherein the first heat exchanger, the second heat exchanger, and the external heat exchanger are the condenser or the evaporator provided in the refrigeration cycle. [Thirteenth Aspect] The heat pump system for a vehicle according to any one of the first to tenth aspects, wherein the heat medium circuit includes a refrigeration cycle through which a refrigerant flows as a first heat medium, and a coolant circuit through which a coolant flows as a second heat medium, the refrigeration cycle includes a compressor that compresses and discharges the refrigerant, a condenser that heats the coolant or the air flowing in the coolant circuit by heat exchange between the refrigerant and the coolant or the air, and condenses the refrigerant, an expansion valve that decompresses and expands the refrigerant condensed in the condenser, an evaporator that cools the coolant or the air flowing in the coolant circuit by heat exchange between the refrigerant and the coolant or the air, and evaporates the refrigerant, and the flow path switching valve (64 to 67) that switches the flow of refrigerant midway through the piping, and the first heat exchanger, the second heat exchanger, and the external heat exchanger are the condenser or the evaporator included in the refrigeration cycle, or heat exchangers included in the coolant circuit. [Fourteenth Aspect] When the maximum cooling mode described in the first aspect is referred to as a first maximum cooling mode, the electronic control device is capable of executing a second maximum cooling mode in which the electronic control device drives each part of the heat medium circuit so that the first heat exchanger, the second heat exchanger, and the external heat exchanger all perform a heat dissipation function, and drives the air path switching mechanism so that the air that has passed through the first heat exchanger and the air that has passed through the second heat exchanger is discharged to the outside of the vehicle compartment through the exhaust opening. [Fifteenth Aspect] A vehicle air conditioning system mounted on a vehicle together with a heat medium circuit (2) that connects a first heat exchanger (11), a second heat exchanger (12), and an external heat exchanger (23) by piping through which a heat medium flows, and that has flow path switching valves (45-67) in the piping for switching the flow of the heat medium, comprising: an air conditioning case (10) having an air passage (16) through which air drawn from outside the vehicle compartment and air drawn from inside the vehicle compartment flow; the first heat exchanger that is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and the heat medium;a second heat exchanger provided downstream of the first heat exchanger in the ventilation passage of the air conditioning case, exchanging heat between the air flowing through the ventilation passage and a heat medium; an outlet opening (13) provided downstream of the first heat exchanger and the second heat exchanger in the air conditioning case, through which air blown out from the ventilation passage into the vehicle compartment flows; an exhaust opening (14, 141, 142) provided downstream of the first heat exchanger in the air conditioning case, through which air exhausted from the ventilation passage to the outside of the vehicle compartment flows; and an air path switching mechanism (15) capable of switching the path of air flow in the ventilation passage between a state in which air flowing through the ventilation passage passes through the first heat exchanger but not the second heat exchanger and flows to the outlet opening or the exhaust opening, and a state in which air flowing through the ventilation passage passes through the second heat exchanger but not the first heat exchanger and flows to the outlet opening or the exhaust opening. and an electronic control device (3) that controls the driving of the air path switching mechanism and each part of the heat medium circuit, wherein the external heat exchanger is provided in a space outside the air conditioning case and performs heat exchange between the air outside the vehicle compartment and the heat medium, and when a function of radiating heat from the heat medium flowing inside the heat exchanger to a substance outside the heat exchanger is called a heat radiation function and a function of absorbing heat from a substance outside the heat exchanger into the heat medium flowing inside the heat exchanger is called a heat absorption function, The electronic control device is capable of executing a maximum cooling mode in which the electronic control device drives each part of the heat medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and drives the air path switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not the other is discharged to the outside of the vehicle compartment through the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not the one is blown into the vehicle compartment through the blow-out opening.

[0125] The fifteenth aspect may be combined with any of the second to fourteenth aspects.

Claims

1. In a vehicle heat pump system, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, A first heat exchanger (11) is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger (12) is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. An external heat exchanger (23) is provided in the space outside the aforementioned air conditioning case and performs heat exchange between the air outside the vehicle compartment and a heat transfer medium, The first heat exchanger, the second heat exchanger, and the external heat exchanger are connected by piping through which a heat transfer medium flows, and the heat transfer medium circuit (2) has flow path switching valves (45-67) in the middle of the piping to switch the flow of the heat transfer medium, The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. Furthermore, the vehicle heat pump system is capable of executing a maximum heating mode by driving the electronic control device to drive each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat absorption function, the other performs a heat dissipation function, and the external heat exchanger performs a heat absorption function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not the other is discharged to the outside of the vehicle compartment from the discharge opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not the other is blown into the vehicle compartment from the blowing opening.

2. In a vehicle heat pump system, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, A first heat exchanger (11) is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger (12) is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. An external heat exchanger (23) is provided in the space outside the aforementioned air conditioning case and performs heat exchange between the air outside the vehicle compartment and a heat transfer medium, The first heat exchanger, the second heat exchanger, and the external heat exchanger are connected by piping through which a heat transfer medium flows, and the heat transfer medium circuit (2) has flow path switching valves (45-67) in the middle of the piping to switch the flow of the heat transfer medium, The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. The heat transfer circuit is configured such that both the first heat exchanger and the second heat exchanger can be switched between heat dissipation and heat absorption functions, in a vehicle heat pump system.

3. In a vehicle heat pump system, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, A first heat exchanger (11) is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger (12) is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. An external heat exchanger (23) is provided in the space outside the aforementioned air conditioning case and performs heat exchange between the air outside the vehicle compartment and a heat transfer medium, The first heat exchanger, the second heat exchanger, and the external heat exchanger are connected by piping through which a heat transfer medium flows, and the heat transfer medium circuit (2) has flow path switching valves (45-67) in the middle of the piping to switch the flow of the heat transfer medium, The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. The airflow switching mechanism is capable of switching the airflow path within the air passage so that the air flowing through the passage passes through both the first heat exchanger and the second heat exchanger to the outlet opening or the discharge opening. The electronic control unit is capable of executing a cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat absorption function, the other performs a function to stop or absorb heat from the flow of the heat transfer medium, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that has passed through both the first heat exchanger and the second heat exchanger is blown into the passenger compartment from the outlet opening. A vehicle heat pump system wherein, when switching from the maximum cooling mode to the cooling mode, the electronic control unit blocks the flow of the high-temperature heat transfer medium in one of the first and second heat exchangers during the maximum cooling mode, switches to the flow of the low-temperature heat transfer medium during the cooling mode, and drives the airflow switching mechanism so that after the temperature of one of the first and second heat exchangers becomes lower than the air temperature upstream of one of the first and second heat exchangers, the air that has passed through both the first and second heat exchangers flows to the outlet opening.

4. In a vehicle heat pump system, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, A first heat exchanger (11) is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger (12) is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. An external heat exchanger (23) is provided in the space outside the aforementioned air conditioning case and performs heat exchange between the air outside the vehicle compartment and a heat transfer medium, The first heat exchanger, the second heat exchanger, and the external heat exchanger are connected by piping through which a heat transfer medium flows, and the heat transfer medium circuit (2) has flow path switching valves (45-67) in the middle of the piping to switch the flow of the heat transfer medium, The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. The heat transfer circuit is configured such that both the first heat exchanger and the second heat exchanger can be switched between heat dissipation and heat absorption functions. A vehicle heat pump system wherein the electronic control device is capable of driving the heat transfer medium circuit so that both the first heat exchanger and the second heat exchanger are in a heat dissipation state, and further capable of driving the heat transfer medium circuit so that both the first heat exchanger and the second heat exchanger are in a heat absorption state.

5. In a vehicle heat pump system, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, A first heat exchanger (11) is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger (12) is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. An external heat exchanger (23) is provided in the space outside the aforementioned air conditioning case and performs heat exchange between the air outside the vehicle compartment and a heat transfer medium, The first heat exchanger, the second heat exchanger, and the external heat exchanger are connected by piping through which a heat transfer medium flows, and the heat transfer medium circuit (2) has flow path switching valves (45-67) in the middle of the piping to switch the flow of the heat transfer medium, An electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, The vehicle includes a heat exchanger (24) for heat-generating components that performs heat exchange between heat-generating components mounted on the vehicle and a heat transfer medium, When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. The heat transfer medium circuit connects the first heat exchanger, the second heat exchanger, the external heat exchanger, and the heat exchanger for the heat-generating component with the piping through which the heat transfer medium flows. A vehicle heat pump system in which the electronic control unit is configured to drive each part of the heat transfer medium circuit such that when the maximum cooling mode is executed, one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, the external heat exchanger performs a heat dissipation function, and the heat exchanger for heat-generating components performs a heat absorption function.

6. The vehicle further comprises a heat exchanger (24) for heat-generating components that performs heat exchange between the heat-generating component and the heat transfer medium, The heat transfer medium circuit connects the first heat exchanger, the second heat exchanger, the external heat exchanger, and the heat exchanger for the heat-generating component with the piping through which the heat transfer medium flows. The vehicle heat pump system according to claim 1, wherein the electronic control unit is configured to drive each part of the heat transfer medium circuit such that when the maximum heating mode is executed, one of the first heat exchanger and the second heat exchanger performs a heat absorption function, the other performs a heat dissipation function, the external heat exchanger performs a heat absorption function, and the heat exchanger for heat-generating components performs a heat dissipation function.

7. In a vehicle heat pump system, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, A first heat exchanger (11) is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger (12) is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. An external heat exchanger (23) is provided in the space outside the aforementioned air conditioning case and performs heat exchange between the air outside the vehicle compartment and a heat transfer medium, The first heat exchanger, the second heat exchanger, and the external heat exchanger are connected by piping through which a heat transfer medium flows, and the heat transfer medium circuit (2) has flow path switching valves (45-67) in the middle of the piping to switch the flow of the heat transfer medium, The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. The heat transfer medium circuit comprises a refrigeration cycle (30) through which a refrigerant, as a first heat transfer medium, flows, and a coolant circuit (40) through which a coolant, as a second heat transfer medium, flows. The refrigeration cycle comprises a compressor (31) that compresses and discharges refrigerant, a condenser (32) that heats the coolant and condenses the refrigerant through heat exchange between the coolant and refrigerant flowing through the coolant circuit, an expansion valve (33) that depressurizes and expands the refrigerant condensed in the condenser, and an evaporator (34) that cools the coolant and evaporates the refrigerant through heat exchange between the coolant and refrigerant flowing through the coolant circuit, all connected by refrigerant piping. A vehicle heat pump system in which the first heat exchanger, the second heat exchanger, and the external heat exchanger are heat exchangers provided in the coolant circuit.

8. In a vehicle heat pump system, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, A first heat exchanger (11) is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger (12) is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. An external heat exchanger (23) is provided in the space outside the aforementioned air conditioning case and performs heat exchange between the air outside the vehicle compartment and a heat transfer medium, The first heat exchanger, the second heat exchanger, and the external heat exchanger are connected by piping through which a heat transfer medium flows, and the heat transfer medium circuit (2) has flow path switching valves (45-67) in the middle of the piping to switch the flow of the heat transfer medium, The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a first maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the discharge opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. Furthermore, the vehicle heat pump system is capable of executing a second maximum cooling mode in which the electronic control unit drives each part of the heat transfer medium circuit so that the first heat exchanger, the second heat exchanger, and the external heat exchanger all perform a heat dissipation function, and drives the airflow switching mechanism so that the air that has passed through the first heat exchanger and the air that has passed through the second heat exchanger is discharged outside the vehicle compartment through the discharge opening.

9. A vehicle air conditioning system mounted in a vehicle, comprising a first heat exchanger (11), a second heat exchanger (12), and an external heat exchanger (23) connected by piping through which a heat transfer medium flows, and a heat transfer medium circuit (2) having flow path switching valves (45-67) in the middle of the piping for switching the flow of the heat transfer medium, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, The first heat exchanger is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, The external heat exchanger is installed in the space outside the air conditioning case and performs heat exchange between the air outside the vehicle compartment and the heat transfer medium. When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. Furthermore, the vehicle air conditioning system is capable of executing a maximum heating mode by driving the electronic control device to drive each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat absorption function, the other performs a heat dissipation function, and the external heat exchanger performs a heat absorption function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not the other is discharged to the outside of the vehicle compartment from the discharge opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not the other is blown into the vehicle compartment from the blowing opening.

10. A vehicle air conditioning system mounted in a vehicle, comprising a first heat exchanger (11), a second heat exchanger (12), and an external heat exchanger (23) connected by piping through which a heat transfer medium flows, and a heat transfer medium circuit (2) having flow path switching valves (45-67) in the middle of the piping for switching the flow of the heat transfer medium, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, The first heat exchanger is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, The external heat exchanger is installed in the space outside the air conditioning case and performs heat exchange between the air outside the vehicle compartment and the heat transfer medium. When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. The aforementioned heat transfer medium circuit is configured to allow both the first heat exchanger and the second heat exchanger to be switched between heat dissipation and heat absorption functions, in an air conditioning system for a vehicle.

11. A vehicle air conditioning system mounted in a vehicle, comprising a first heat exchanger (11), a second heat exchanger (12), and an external heat exchanger (23) connected by piping through which a heat transfer medium flows, and a heat transfer medium circuit (2) having flow path switching valves (45-67) in the middle of the piping for switching the flow of the heat transfer medium, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, The first heat exchanger is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, The external heat exchanger is installed in the space outside the air conditioning case and performs heat exchange between the air outside the vehicle compartment and the heat transfer medium. When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. The airflow switching mechanism is capable of switching the airflow path within the air passage so that the air flowing through the passage passes through both the first heat exchanger and the second heat exchanger to the outlet opening or the discharge opening. The electronic control unit is capable of executing a cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat absorption function, the other performs a function to stop or absorb heat from the flow of the heat transfer medium, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that has passed through both the first heat exchanger and the second heat exchanger is blown into the passenger compartment from the outlet opening. The vehicle air conditioning system comprises an electronic control unit that, when switching from the maximum cooling mode to the cooling mode, shuts off the flow of the high-temperature heat transfer medium in one of the first and second heat exchangers during the maximum cooling mode, switches to the flow of the low-temperature heat transfer medium during the cooling mode, and drives the airflow switching mechanism so that after the temperature of one of the first and second heat exchangers becomes lower than the air temperature upstream of one of the first and second heat exchangers, the air that has passed through both the first and second heat exchangers flows to the outlet opening.

12. A vehicle air conditioning system mounted in a vehicle, comprising a heat transfer medium circuit (2) which connects a first heat exchanger (11), a second heat exchanger (12), and an external heat exchanger (23) with piping through which a heat transfer medium flows, and which has flow path switching valves (45-67) in the middle of the piping to switch the flow of the heat transfer medium, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, The first heat exchanger is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, The external heat exchanger is installed in the space outside the air conditioning case and performs heat exchange between the air outside the vehicle compartment and the heat transfer medium. When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. The heat transfer circuit is configured such that both the first heat exchanger and the second heat exchanger can be switched between heat dissipation and heat absorption functions. The aforementioned electronic control device is capable of driving the heat transfer medium circuit so that both the first heat exchanger and the second heat exchanger are in a heat dissipation state, and further capable of driving the heat transfer medium circuit so that both the first heat exchanger and the second heat exchanger are in a heat absorption state, in an air conditioning system for a vehicle.

13. A vehicle air conditioning system mounted in a vehicle, comprising a heat transfer medium circuit (2) which connects a first heat exchanger (11), a second heat exchanger (12), and an external heat exchanger (23) with piping through which a heat transfer medium flows, and which has flow path switching valves (45-67) in the middle of the piping to switch the flow of the heat transfer medium, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, The first heat exchanger is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. An electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, The vehicle includes a heat exchanger (24) for heat-generating components that performs heat exchange between heat-generating components mounted on the vehicle and a heat transfer medium, The external heat exchanger is installed in the space outside the air conditioning case and performs heat exchange between the air outside the vehicle compartment and the heat transfer medium. When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. The heat transfer medium circuit connects the first heat exchanger, the second heat exchanger, the external heat exchanger, and the heat exchanger for the heat-generating component with the piping through which the heat transfer medium flows. The vehicle air conditioning system is configured such that, when executing the maximum cooling mode, the electronic control unit drives each part of the heat transfer medium circuit such that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, the external heat exchanger performs a heat dissipation function, and the heat exchanger for heat-generating components performs a heat absorption function.

14. The vehicle further comprises a heat exchanger (24) for heat-generating components that performs heat exchange between the heat-generating component and the heat transfer medium, The heat transfer medium circuit connects the first heat exchanger, the second heat exchanger, the external heat exchanger, and the heat exchanger for the heat-generating component with the piping through which the heat transfer medium flows. The vehicle air conditioning system according to claim 9, wherein the electronic control unit is configured to drive each part of the heat transfer medium circuit such that when the maximum heating mode is executed, one of the first heat exchanger and the second heat exchanger performs a heat absorption function, the other performs a heat dissipation function, the external heat exchanger performs a heat absorption function, and the heat exchanger for heat-generating components performs a heat dissipation function.

15. A vehicle air conditioning system mounted in a vehicle, comprising a first heat exchanger (11), a second heat exchanger (12), and an external heat exchanger (23) connected by piping through which a heat transfer medium flows, and a heat transfer medium circuit (2) having flow path switching valves (45-67) in the middle of the piping for switching the flow of the heat transfer medium, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, The first heat exchanger is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, The external heat exchanger is installed in the space outside the air conditioning case and performs heat exchange between the air outside the vehicle compartment and the heat transfer medium. When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the exhaust opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. The heat transfer medium circuit comprises a refrigeration cycle (30) through which a refrigerant, as a first heat transfer medium, flows, and a coolant circuit (40) through which a coolant, as a second heat transfer medium, flows. The refrigeration cycle comprises a compressor (31) that compresses and discharges refrigerant, a condenser (32) that heats the coolant and condenses the refrigerant through heat exchange between the coolant and refrigerant flowing through the coolant circuit, an expansion valve (33) that depressurizes and expands the refrigerant condensed in the condenser, and an evaporator (34) that cools the coolant and evaporates the refrigerant through heat exchange between the coolant and refrigerant flowing through the coolant circuit, all connected by refrigerant piping. The first heat exchanger, the second heat exchanger, and the external heat exchanger are heat exchangers provided in the coolant circuit, in a vehicle air conditioning system.

16. A vehicle air conditioning system mounted in a vehicle, comprising a heat transfer medium circuit (2) which connects a first heat exchanger (11), a second heat exchanger (12), and an external heat exchanger (23) with piping through which a heat transfer medium flows, and which has flow path switching valves (45-67) in the middle of the piping to switch the flow of the heat transfer medium, An air conditioning case (10) having a ventilation passage (16) through which air drawn in from outside the vehicle and air drawn in from inside the vehicle flows, The first heat exchanger is provided in the air passage of the air conditioning case and performs heat exchange between the air flowing through the air passage and a heat transfer medium, A second heat exchanger is provided downstream of the first heat exchanger in the air passage of the air conditioning case, and performs heat exchange between the air flowing through the air passage and a heat transfer medium. In the aforementioned air conditioning case, an outlet opening (13) is provided downstream of the first heat exchanger and the second heat exchanger, through which air blown from the ventilation passage into the passenger compartment flows, In the aforementioned air conditioning case, there are discharge openings (14, 141, 142) provided downstream of the first heat exchanger through which air discharged from the ventilation passage to the outside of the vehicle compartment flows, An airflow path switching mechanism (15) is provided that can switch the airflow path within the airflow path between a state in which the air flowing through the airflow path passes through the first heat exchanger but not through the second heat exchanger and is directed to the outlet opening or the discharge opening, and a state in which the air flowing through the airflow path passes through the second heat exchanger but not through the first heat exchanger and is directed to the outlet opening or the discharge opening. The system includes an electronic control device (3) that controls the operation of each part of the airflow switching mechanism and the heat transfer circuit, The external heat exchanger is installed in the space outside the air conditioning case and performs heat exchange between the air outside the vehicle compartment and the heat transfer medium. When we define the function of releasing heat from a heat transfer medium flowing inside a heat exchanger to a substance outside the heat exchanger as the heat dissipation function, and the function of absorbing heat from a substance outside the heat exchanger into a heat transfer medium flowing inside the heat exchanger as the heat absorption function, The electronic control unit is capable of executing a first maximum cooling mode by driving each part of the heat transfer medium circuit so that one of the first heat exchanger and the second heat exchanger performs a heat dissipation function, the other performs a heat absorption function, and the external heat exchanger performs a heat dissipation function, and by driving the airflow switching mechanism so that air that passes through one of the first heat exchanger and the second heat exchanger but not through the other is discharged to the outside of the vehicle compartment from the discharge opening, and air that passes through the other of the first heat exchanger and the second heat exchanger but not through the other is blown into the vehicle compartment from the blowing opening. Furthermore, the vehicle air conditioning system is capable of executing a second maximum cooling mode in which the electronic control unit drives each part of the heat transfer medium circuit so that the first heat exchanger, the second heat exchanger, and the external heat exchanger all perform a heat dissipation function, and drives the airflow switching mechanism so that the air that has passed through the first heat exchanger and the air that has passed through the second heat exchanger is discharged outside the vehicle compartment through the discharge opening.