Vehicle air conditioning system

Abstract

To provide a vehicular air conditioner which comprises a first heating medium circuit regarding waste heat generated by travelling, and a second heating medium circuit, and can achieve stable air conditioning performance by effectively utilizing the first and the second heating medium circuits.SOLUTION: A vehicular air conditioner 1 comprises: a first heating medium circuit 10; a second heating medium circuit 20; a heat exchanger 13 between heating mediums; and a control device 60. The first heating medium circuit 10 circulates a first heating medium through an engine 11a that is a first heat source 11 generating heat while the vehicle travels. The second heating medium circuit 20 circulates a second heating medium through a refrigeration cycle 30 as a second heat source 21 which can adjust heat quantity to be generated and a heat core 23 which heats blowing air supplied to an air-conditioning object space by heat exchange. The heat exchanger 13 between heating mediums performs heat exchange between the first heating medium circulating in the first heating medium circuit 10 and the second heating medium circulating in the second heating medium circuit 20. The control device 60 controls behavior of the first heating medium circuit 10 and the second heating medium circuit 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a vehicle air conditioner that can utilize waste heat generated in in-vehicle equipment during driving for heating.

Background Art

[0002] Conventionally, in a vehicle air conditioner, a technique for realizing heating inside a vehicle using waste heat generated in in-vehicle equipment during vehicle driving is known. For example, the technique described in Patent Document 1 discloses a technique related to a vehicle air conditioner that can utilize waste heat of an engine mounted on a vehicle for heating inside the vehicle.

[0003] In Patent Document 1, by flowing a heat medium that has passed through the engine into a heater core, waste heat of the engine is utilized to heat the blown air supplied into the vehicle interior. Also, in Patent Document 1, heating using a refrigeration cycle can be realized by circulating the same heat medium through a radiator that is a component of the refrigeration cycle.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the vehicle air conditioner of Patent Document 1, an engine as in-vehicle equipment and a radiator that is a component of the refrigeration cycle are arranged in a heating-side heat medium circuit through which a single type of heat medium circulates.

[0006] Therefore, when attempting to utilize engine waste heat and heat generated by the refrigeration cycle for heating, it is necessary to circulate the heat transfer medium in the heating-side heat transfer medium circuit through the engine, the components of the refrigeration cycle (i.e., radiators), and the heater core. In other words, when attempting to utilize engine waste heat and heat from the refrigeration cycle for heating, it becomes necessary to switch the circuit configuration of the heating-side heat transfer medium circuit by controlling the operation of control valves, etc.

[0007] Furthermore, simply switching the circuit configuration of the heating-side heat transfer fluid circuit will result in an increase or decrease in water flow resistance due to the change in circuit configuration. This will cause fluctuations in the flow rate of the heat transfer fluid to the heater core, and therefore, it is expected that the heating performance in the vehicle interior will fluctuate.

[0008] Furthermore, in the configuration of Patent Document 1, the engine and radiator are arranged in the second heat transfer medium circuit, but it is difficult to utilize the exhaust heat from the engine and the heat generated by the refrigeration cycle for different purposes at the same time.

[0009] In view of the above points, this disclosure aims to provide a vehicle air conditioning system that can achieve stable air conditioning performance by effectively utilizing a first heat transfer medium circuit and a second heat transfer medium circuit related to the waste heat generated during driving. [Means for solving the problem]

[0010] An air conditioning system for a vehicle according to one aspect of the present disclosure includes a first heat transfer medium circuit (10), a second heat transfer medium circuit (20), a heat transfer medium heat exchanger (13), and a control unit (60). The first heat transfer medium circuit circulates a first heat transfer medium via a first heat source (11, 11a) that generates heat in conjunction with the movement of the vehicle. The second heat transfer medium circuit circulates a second heat transfer medium via a second heat source (21, 30, 42) whose amount of heat generated can be adjusted, and a heater core (23) that heats the blown air supplied to the air-conditioned space by heat exchange. The heat transfer medium heat exchanger exchanges heat between the first heat transfer medium circulating in the first heat transfer medium circuit and the second heat transfer medium circulating in the second heat transfer medium circuit. The control unit controls the operation of the first heat transfer medium circuit and the second heat transfer medium circuit. Furthermore, the vehicle air conditioning system includes a heat quantity adjustment unit (45) and a heat dissipation unit (46). The heat quantity adjustment unit adjusts the amount of heat supplied to the heat exchanger. The heat dissipation unit dissipates the amount of heat that was not supplied to the heat exchanger by the heat quantity adjustment unit. The heat quantity adjustment unit (45) includes a bypass flow path (15) and a flow rate adjustment unit (16). The bypass flow path allows the first heat medium to flow in the first heat medium circuit, bypassing the heat exchanger. The flow rate adjustment unit adjusts the flow rate of the first heat medium flowing towards the bypass flow path and the flow rate of the first heat medium flowing towards the heat exchanger. The heat dissipation unit (46) is an external heat sink (14) located in the flow path of the first heat medium circuit, which dissipates the heat of the first heat medium to the outside.

[0011] Therefore, with a vehicle air conditioning system, the first heat medium, which recovers heat generated by the first heat source, and the second heat medium, which recovers heat generated by the second heat source, can exchange heat in a heat exchanger. In other words, the vehicle air conditioning system can appropriately utilize the amount of heat generated by the first and second heat sources to compensate for any surplus or deficit, stabilize the amount of heat supplied to the heater core, and stabilize the heating performance.

[0012] The reference numerals in parentheses next to each means described in this section and in the claims indicate the correspondence with the specific means described in the embodiments described later. [Brief explanation of the drawing]

[0013] [Figure 1] This is a diagram showing the configuration of a vehicle air conditioning system according to the first embodiment. [Figure 2] This is an explanatory diagram showing the configuration of an indoor air conditioning unit according to the first embodiment. [Figure 3] This is a block diagram showing the control system of a vehicle air conditioning system according to the first embodiment. [Figure 4] This is an explanatory diagram showing the first circulation mode in the first heat transfer medium circuit. [Figure 5] This is an explanatory diagram showing the second circulation mode in the first heat transfer medium circuit. [Figure 6] This is an explanatory diagram showing the third circulation mode in the first heat transfer medium circuit. [Figure 7] This is an explanatory diagram showing the fourth circulation mode in the first heat transfer medium circuit. [Figure 8] This is an explanatory diagram showing an example of the initial state and transition state in the first switching control of a vehicle air conditioning system. [Figure 9] This is an explanatory diagram showing an example of the completed switching state in the first switching control of a vehicle air conditioning system. [Figure 10] This is an explanatory diagram showing an example of the initial state in the second switching control of a vehicle air conditioning system. [Figure 11] This is an explanatory diagram showing an example of a transition state in the second switching control of a vehicle air conditioning system. [Figure 12]It is an explanatory diagram showing an example of a switching completion state in the second switching control of the vehicle air conditioner. [Figure 13] It is a configuration diagram of a vehicle air conditioner according to the second embodiment. [Figure 14] It is a configuration diagram of a vehicle air conditioner according to the third embodiment. [Figure 15] It is a configuration diagram of a vehicle air conditioner according to the fourth embodiment. [Figure 16] It is a configuration diagram of a vehicle air conditioner according to the fifth embodiment.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, a plurality of embodiments for implementing the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to those described in the preceding embodiment may be denoted by the same reference numerals and redundant descriptions may be omitted. When only a part of the configuration is described in each embodiment, other embodiments described previously can be applied to other parts of the configuration. Not only combinations of parts that are explicitly shown to be combinable in each embodiment, but also partial combinations of embodiments are possible as long as there is no problem with the combination, even if not explicitly stated.

[0015] (First Embodiment) The first embodiment in the present disclosure will be described with reference to FIGS. 1 to 12. In the first embodiment, the vehicle air conditioner 1 according to the present disclosure is applied to a hybrid vehicle. A hybrid vehicle is a vehicle that obtains driving force for vehicle travel from an internal combustion engine (that is, engine 11a) and a driving electric motor for travel.

[0016] The vehicle air conditioning system 1 provides air conditioning to the passenger compartment, which is the space to be air-conditioned, in a hybrid vehicle. The vehicle air conditioning system 1 can switch between three air conditioning operating modes for the passenger compartment: cooling mode, heating mode, and dehumidifying heating mode. Cooling mode is an operating mode in which the air blown into the passenger compartment is cooled and then blown into the passenger compartment. Heating mode is an operating mode in which the air blown into the passenger compartment is heated and then blown into the passenger compartment. Dehumidifying heating mode is an operating mode in which the air blown into the passenger compartment is reheated after being cooled and dehumidified, and then blown into the passenger compartment to provide dehumidifying heating to the passenger compartment.

[0017] Next, the specific configuration of the vehicle air conditioning system 1 according to the first embodiment will be described with reference to Figures 1 and 2. As shown in Figure 1, the vehicle air conditioning system 1 according to the first embodiment includes a first heat transfer medium circuit 10, a second heat transfer medium circuit 20, and a heat transfer medium heat exchanger 13.

[0018] The first heat transfer medium circuit 10 is a heat transfer medium circuit configured to circulate a first heat transfer medium via a first heat source 11 that generates heat in conjunction with the operation of the hybrid vehicle. In the first embodiment, the first heat source 11 is an engine 11a, which is an internal combustion engine that generates the driving force for the hybrid vehicle.

[0019] The second heat transfer medium circuit 20 is a heat transfer medium circuit configured such that the second heat transfer medium circulates via a second heat source 21 whose heat output can be controlled by a control device 60, etc., which will be described later. In the first embodiment, a refrigeration cycle 30 is used as the second heat source 21.

[0020] The vehicle air conditioning system 1 comprises an interior air conditioning unit 50 and a control device 60. In other words, the vehicle air conditioning system 1 according to the first embodiment can effectively utilize the heat generated by the first heat source 11 and the heat generated by the second heat source 21 via a heat transfer medium heat exchanger 13 to adjust the temperature of the air supplied from the interior air conditioning unit 50 to the vehicle interior, which is the space to be air-conditioned.

[0021] First, the configuration of the first heat transfer medium circuit 10 in the vehicle air conditioning system 1 will be explained with reference to Figure 1. As described above, the first heat transfer medium circuit 10 is a circulation circuit for transferring heat generated in the first heat source 11 via the first heat transfer medium, and includes an engine 11a as the first heat source 11, a first heat transfer medium pump 12, and a heat transfer medium heat exchanger 13.

[0022] Furthermore, as the first heat transfer medium in the first heat transfer medium circuit 10, a solution containing ethylene glycol, antifreeze, etc., can be used.

[0023] As described above, the first heat source 11 in the vehicle air conditioning system 1 is composed of equipment installed in the hybrid vehicle that incidentally generates heat as a result of operation for purposes such as driving. In the first embodiment, an engine 11a that generates driving force by burning fuel is used as the first heat source 11.

[0024] The engine 11a has a water jacket through which a first heat transfer medium flows. The engine 11a is cooled by the flow of the first heat transfer medium through the water jacket. The waste heat generated by the combustion of fuel in the engine 11a is transferred to the first heat transfer medium flowing through the water jacket. That is, the first heat transfer medium is heated by the waste heat of the engine 11a.

[0025] The inlet side of the first heat transfer medium in the engine 11a is connected to the discharge port of the first heat transfer medium pump 12 via a branch section 17 formed in the shape of a three-way joint. The first heat transfer medium pump 12 is a heat transfer medium pump that pumps the first heat transfer medium in order to circulate it in the first heat transfer medium circuit 10. The first heat transfer medium pump 12 is an electric pump whose rotational speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 60. The suction port of the first heat transfer medium pump 12 is connected to the outlet side of the heat transfer medium in the outside air radiator 14.

[0026] The heat exchanger 13 is a heat exchanger that exchanges heat between a first heat transfer medium circulating in a first heat transfer medium circuit 10 and a second heat transfer medium circulating in a second heat transfer medium circuit 20. The heat exchanger 13 has a first heat transfer medium passage 13a through which the first heat transfer medium of the first heat transfer medium circuit 10 flows, and a second heat transfer medium passage 13b through which the second heat transfer medium of the second heat transfer medium circuit 20 flows.

[0027] The heat exchanger 13 is made of the same type of metal (aluminum alloy in the first embodiment) that has excellent heat transfer properties, and each component is integrated by brazing. Therefore, the first heat transfer medium flowing through the first heat transfer medium passage 13a and the second heat transfer medium flowing through the second heat transfer medium passage 13b can exchange heat with each other.

[0028] As shown in Figure 1, the first heat transfer medium circuit 10 is equipped with an outside air radiator 14 and a four-way valve 16. The outside air radiator 14 is a radiator that releases the heat contained in the first heat transfer medium circulating in the first heat transfer medium circuit 10 to the outside air.

[0029] The outside air radiator 14 can be positioned on the front side of the vehicle's hood and configured to allow outside air to flow from the front to the rear of the vehicle as the hybrid vehicle is driven. When the outside air radiator 14 is positioned in this way, the airflow from the vehicle passes through the heat exchange section of the outside air radiator 14, so heat can be dissipated to the outside air using the airflow. Therefore, the outside air radiator 14 is an example of an external radiator.

[0030] The four-way valve 16 is a flow control valve having four inlet and outlet ports for the first heat transfer medium. The four-way valve 16 adjusts the flow rate of the first heat transfer medium flowing out of the other inlet ports with respect to the first heat transfer medium flowing in from any of the four inlet ports.

[0031] One of the inlet and outlet ports of the four-way valve 16 is connected to one of the inlet and outlet ports of the three-way joint-shaped branch section 17, and the other inlet and outlet port of the four-way valve 16 is connected to the outlet side of the heat transfer medium passage of the first heat source 11. Another inlet and outlet port of the four-way valve 16 is connected to the inlet side of the first heat transfer medium passage 13a of the heat transfer medium heat exchanger 13. The remaining inlet and outlet port of the four-way valve 16 is connected to one of the inlet and outlet ports of the three-way joint-shaped junction section 18 via a bypass passage 15, which will be described later.

[0032] As described above, the branch section 17 is formed as a three-way joint structure, with one of the three inlet / outlet ports serving as the inlet and the remaining two as outlets. As shown in Figure 1, the inlet of the branch section 17 is connected to the discharge port side of the first heat transfer fluid pump 12. One of the outlets of the branch section 17 is connected to the inlet side of the heat transfer fluid passage of the first heat source 11, and the other outlet of the branch section 17 is connected to one of the inlet / outlet ports of the four-way valve 16.

[0033] The confluence section 18 is formed in a three-way joint structure, similar to the branch section 17, with one of the three inlet / outlet ports serving as the outlet and the remaining two as the inlet ports. As shown in Figure 1, the outlet port at the confluence section is connected to the heat transfer medium inlet side of the outside air radiator 14.

[0034] Furthermore, one inlet of the junction 18 is connected to the outlet side of the first heat transfer medium passage 13a in the heat transfer medium heat exchanger 13, and the other inlet of the junction 18 is connected to the remaining inlet outlet of the four-way valve 16 via the bypass passage 15.

[0035] As a result, in the first heat transfer medium circuit 10, the first heat transfer medium that flows into the four-way valve 16 can be routed around the heat transfer medium heat exchanger 13 and flow into the confluence section 18 and the outside air radiator 14. In other words, the four-way valve 16 can adjust the balance between the flow rate of the first heat transfer medium flowing to the bypass channel 15 and the flow rate of the first heat transfer medium flowing to the heat transfer medium heat exchanger 13, thereby making it possible to adjust the amount of heat supplied to the heat transfer medium heat exchanger 13.

[0036] Therefore, the bypass channel 15, the four-way valve 16, the branch section 17, and the junction section 18 correspond to an example of the heat quantity adjustment section 45 in the first heat transfer medium circuit 10. Also, the outside air radiator 14 corresponds to an example of the heat dissipation section in the first heat transfer medium circuit 10.

[0037] In the first heat transfer medium circuit 10 configured in this way, multiple circulation modes of the first heat transfer medium can be realized by controlling the operation of the four-way valve 16. Details of the first to fourth circulation modes realized in the first heat transfer medium circuit 10 will be explained later with reference to the drawings.

[0038] Next, the configuration of the second heat transfer medium circuit 20 in the vehicle air conditioning system 1 will be described with reference to the drawings. The second heat transfer medium circuit 20 is a heat transfer medium circuit that circulates the second heat transfer medium, and as shown in Figure 1, it has a second heat transfer medium passage 13b of the heat transfer medium heat exchanger 13, a second heat transfer medium pump 22, a heater core 23, and a refrigeration cycle 30 as the second heat source 21.

[0039] Furthermore, the second heat transfer medium circulating in the second heat transfer medium circuit 20 can be a solution containing ethylene glycol, antifreeze, or the like. The second heat transfer medium is configured not to mix with the first heat transfer medium in the first heat transfer medium circuit 10. Therefore, as long as the first and second heat transfer mediums do not mix, there is no prerequisite for using the same type of heat transfer medium.

[0040] The second heat source 21 is a heat source device that heats the second heat transfer medium circulating in the second heat transfer medium circuit 20, and is a heat source whose heat output can be adjusted by the operation control of the control device 60. The outlet side of the heater core 23 is connected to the inlet of the second heat transfer medium to the second heat source 21, and the suction side of the second heat transfer medium pump 22 is connected to the outlet of the second heat transfer medium in the second heat source 21. In the first embodiment, a refrigeration cycle 30 is used as the second heat source 21. The configuration of the refrigeration cycle 30 will be described in detail later.

[0041] The second heat transfer fluid pump 22 is a heat transfer fluid pump that pumps the second heat transfer fluid in order to circulate it in the second heat transfer fluid circuit 20. The second heat transfer fluid pump 22 has the same configuration as the first heat transfer fluid pump 12 and is an electric pump whose rotational speed (i.e., pumping capacity) is controlled by a control voltage output from the control device 60.

[0042] The heater core 23 is a heat exchanger that heats the blown air supplied to the vehicle interior from inside the indoor air conditioning unit 50 by exchanging heat between the second heat medium, which is heated by the heat medium heat exchanger 13 and the second heat source 21, etc. As shown in Figure 2, the heater core 23 is located inside the air conditioning case 51 of the indoor air conditioning unit 50. Therefore, the heater core 23 is an example of a heating heat exchanger.

[0043] As shown in Figure 1, the second heat transfer medium circuit 20 includes a heat transfer medium three-way valve 25 and a heat transfer medium radiator 27. The heat transfer medium three-way valve 25 is an electrically operated three-way flow control valve having three inlets and outlets. The heat transfer medium three-way valve 25 is arranged so that one of the three inlets and outlets is the inlet and the other two are the outlets. In other words, the heat transfer medium three-way valve 25 functions as a branching point with respect to the flow of the second heat transfer medium.

[0044] The inlet of the three-way valve 25 for the heat transfer medium is connected to the outlet side of the second heat transfer medium passage 13b of the heat transfer medium heat exchanger 13. One outlet of the three-way valve 25 for the heat transfer medium is connected to the inlet side of the heater core 23, and the other outlet of the three-way valve 25 for the heat transfer medium is connected to the inlet side of the heat transfer medium radiator 27 via the heat transfer medium bypass passage 24.

[0045] Therefore, in the second heat transfer medium circuit 20, it is possible to realize two modes of operation: one in which the second heat transfer medium that has flowed from the heat transfer medium heat exchanger 13 to the heat transfer medium three-way valve 25 flows toward the heater core 23, and the other in which it flows toward the heat transfer medium radiator 27. In other words, the heat transfer medium three-way valve 25 can adjust the balance between the flow rate of the second heat transfer medium flowing toward the heater core 23 and the flow rate of the second heat transfer medium flowing toward the heat transfer medium radiator 27, thereby adjusting the amount of heat supplied to the heat transfer medium heat exchanger 13.

[0046] The heat transfer fluid radiator 27 exchanges heat between the second heat transfer fluid, which has been heated by the heat transfer fluid refrigerant heat exchanger 32, and the outside air, thereby releasing the heat contained in the second heat transfer fluid to the outside air. The heat transfer fluid radiator 27 can be positioned on the front side of the vehicle's hood. As a result, as the hybrid vehicle is driven, the outside air flows from the front to the rear of the vehicle and passes through the heat exchange section of the heat transfer fluid radiator 27, allowing the heat contained in the second heat transfer fluid to be released to the outside air using the airflow from the vehicle.

[0047] A three-way joint structure heat transfer medium confluence section 26 is connected to the heat transfer medium outlet of the heat transfer medium radiator 27 via a heat transfer medium bypass channel 24. The heat transfer medium confluence section 26 uses one of the three inlet / outlet ports of the three-way joint structure as the outlet and the remaining two as the inlet ports.

[0048] As shown in Figure 1, the outlet of the heat transfer medium confluence section 26 is connected to the inlet side of the second heat transfer medium passage 13b in the heat transfer medium heat exchanger 13. The discharge side of the second heat transfer medium pump 22 is connected to one of the outlets of the heat transfer medium confluence section 26, and the outlet side of the heat transfer medium radiator 27 is connected to the other outlet of the heat transfer medium confluence section 26 via the heat transfer medium bypass passage 24. Therefore, the heat transfer medium confluence section 26 can combine the flow of the second heat transfer medium that has passed through the heat transfer medium radiator 27 with the flow of the second heat transfer medium that has passed through the heater core 23 and the second heat source 21.

[0049] Thus, in the second heat transfer medium circuit 20 of the first embodiment, the heater core 23 and the heat transfer medium radiator 27 are connected in parallel with respect to the flow of the second heat transfer medium through the second heat transfer medium passage 13b of the heat transfer medium heat exchanger 13. The three-way valve 25 can continuously adjust the flow rate ratio between the flow rate of the second heat transfer medium flowing into the heater core 23 and the flow rate of the second heat transfer medium flowing into the heat transfer medium radiator 27 in the second heat transfer medium circuit 20.

[0050] In other words, by controlling the operation of the three-way valve 25 for the heat transfer medium, it is possible to adjust the amount of heat from the second heat transfer medium that is released to the outside air by the heat transfer medium radiator 27 and the amount of heat from the second heat transfer medium that is released to the blown air by the heater core 23.

[0051] Therefore, the heat transfer medium bypass channel 24, the heat transfer medium three-way valve 25, and the heat transfer medium confluence section 26 correspond to an example of the heat quantity adjustment section 45 in the second heat transfer medium circuit 20. Also, the heat transfer medium radiator 27 corresponds to an example of the heat dissipation section in the second heat transfer medium circuit 20.

[0052] In the second heat transfer medium circuit 20, the second heat source 21 is positioned upstream of the heat transfer medium heat exchanger 13 with respect to the flow of the second heat transfer medium. When heating the blown air in the heater core 23, any heat insufficient from the second heat source 21 can be compensated for by the heat generated by the first heat source 11 via the heat transfer medium heat exchanger 13. In other words, by positioning the second heat source 21 upstream of the heat transfer medium heat exchanger 13, the heat from the first heat source 11 can be efficiently utilized to achieve the desired heating capacity.

[0053] Furthermore, the heater core 23 is positioned upstream of the second heat source 21 with respect to the flow of the second heat transfer medium. Since the heat contained in the second heat transfer medium is used to heat the blown air in the heater core 23 before flowing into the second heat source 21, the heat exchange efficiency when the second heat transfer medium absorbs heat in the second heat source 21 can be improved.

[0054] As shown in Figure 1, the heat exchanger 13 is positioned upstream of the three-way valve 25, which functions as a branch to the heat bypass channel 24 with respect to the flow of the second heat medium in the second heat medium circuit 20. This allows the amount of heat dissipated by the heat radiator 27 located in the heat bypass channel 24 to be maximized in the second heat medium circuit 20.

[0055] Next, the refrigeration cycle 30, which constitutes the second heat source 21 of the vehicle air conditioning system 1, will be described with reference to the drawings. The refrigeration cycle 30 is a vapor compression type refrigeration cycle device. As shown in Figure 1, the refrigeration cycle 30 has a compressor 31, a refrigerant heat exchanger 32, a first expansion valve 34, a first evaporator 35, a second expansion valve 36, and a second evaporator 37. The refrigeration cycle 30 can pump up the heat absorbed in the first evaporator 35 and the second evaporator 37 and heat the second heat transfer medium in the refrigerant heat exchanger 32.

[0056] Furthermore, the refrigeration cycle 30 of the vehicle air conditioning system 1 uses an HFO-based refrigerant (specifically, HFO1234yf) as the refrigerant, and constitutes a subcritical refrigeration cycle in which the high-pressure refrigerant pressure does not exceed the critical pressure of the refrigerant. The refrigerant is mixed with refrigeration oil to lubricate the compressor 31. As the refrigeration oil, PAG oil (polyalkylene glycol oil), which is compatible with the liquid-phase refrigerant, is used. A portion of the refrigeration oil circulates in the cycle together with the refrigerant.

[0057] The compressor 31 inhales, compresses, and discharges refrigerant in the refrigeration cycle 30. The compressor 31 is located inside the vehicle's hood. The compressor 31 is an electric compressor in which a fixed-capacity compression mechanism with a fixed discharge capacity is rotationally driven by an electric motor. The rotational speed (i.e., refrigerant discharge capacity) of the compressor 31 is controlled by a control signal output from the control device 60, which will be described later.

[0058] The discharge port of the compressor 31 is connected to the inlet side of the refrigerant passage 32b in the heat transfer medium refrigerant heat exchanger 32. The heat transfer medium refrigerant heat exchanger 32 is a heat exchanger that dissipates the heat contained in the high-pressure refrigerant discharged from the compressor 31 to the second heat transfer medium circulating in the second heat transfer medium circuit 20, thereby heating the second heat transfer medium.

[0059] The heat transfer medium refrigerant heat exchanger 32 has a heat transfer medium passage 32a through which the second heat transfer medium of the second heat transfer medium circuit 20 flows, and a refrigerant passage 32b through which the refrigerant of the refrigeration cycle 30 flows. The heat transfer medium refrigerant heat exchanger 32 is made of the same type of metal (aluminum alloy in the first embodiment) which has excellent heat transfer properties, and each component is integrated by brazing.

[0060] As a result, the high-pressure refrigerant flowing through the refrigerant passage 32b and the second heat transfer medium flowing through the heat transfer medium passage 32a can exchange heat with each other. The heat transfer medium refrigerant heat exchanger 32 is an example of a condenser that dissipates the heat contained in the high-pressure refrigerant.

[0061] A refrigerant branch section 33a with a three-way joint structure is connected to the outlet of the refrigerant passage 32b of the heat transfer medium refrigerant heat exchanger 32. In the refrigerant branch section 33a, one of the three inlet / outlet ports is used as the refrigerant inlet, and the remaining two are used as the refrigerant outlets. In other words, the refrigerant branch section 33a is a branch section that divides the flow of liquid phase refrigerant that flows out of the heat transfer medium refrigerant heat exchanger 32.

[0062] One refrigerant outlet of the refrigerant branching section 33a is connected to the refrigerant inlet side of the first evaporator 35 via the first expansion valve 34. The other refrigerant outlet of the refrigerant branching section is connected to the refrigerant inlet side of the second evaporator 37 via the second expansion valve 36.

[0063] The first expansion valve 34 reduces the pressure of the refrigerant that has flowed out from one of the refrigerant outlets of the refrigerant branch section 33a, at least during the air conditioning operation mode in which the blown air is cooled. The first expansion valve 34 is an electrically operated variable throttling mechanism and has a valve body and an electric actuator. The first expansion valve 34 is composed of a so-called electric expansion valve.

[0064] The valve body of the first expansion valve 34 is configured to change the passage opening (in other words, the throttle opening) of the refrigerant passage. The electric actuator has a stepping motor that changes the throttle opening of the valve body. The operation of the first expansion valve 34 is controlled by a control signal output from the control device 60.

[0065] Furthermore, the first expansion valve 34 is composed of a variable throttle mechanism that has a fully open function that fully opens the refrigerant passage when the throttle opening is fully open, and a fully closed function that closes the refrigerant passage when the throttle opening is fully closed. In other words, the first expansion valve 34 can prevent the refrigerant from reducing pressure by fully opening the refrigerant passage.

[0066] Furthermore, the first expansion valve 34 can block the inflow of refrigerant to the first evaporator 35 by closing the refrigerant passage. In other words, the first expansion valve 34 combines the function of a pressure reducing unit that reduces the pressure of the refrigerant and the function of a refrigerant circuit switching unit that switches between refrigerant circuits. In addition, the first expansion valve 34 can adjust the flow rate of refrigerant flowing into the first evaporator 35 by adjusting the throttling opening of the refrigerant passage.

[0067] The outlet of the first expansion valve 34 is connected to the refrigerant inlet side of the first evaporator 35. As shown in Figure 2, the first evaporator 35 is located inside the air conditioning case 51 of the indoor air conditioning unit 50. The first evaporator 35 cools the air by exchanging heat between the low-pressure refrigerant, which has been reduced in pressure by the first expansion valve 34, and the air being supplied, at least during air conditioning operation mode in which the supplied air is cooled.

[0068] As shown in Figure 1, a second expansion valve 36 is connected to the other refrigerant outlet in the refrigerant branch section 33a. The second expansion valve 36, like the first expansion valve 34, is an electrically operated variable throttling mechanism and has a valve body and an electric actuator. In other words, the second expansion valve 36 is composed of a so-called electric expansion valve and has a fully open function and a fully closed function.

[0069] In other words, the second expansion valve 36 can prevent the refrigerant from reducing pressure by fully opening the refrigerant passage. Furthermore, the second expansion valve 36 can block the inflow of refrigerant to the second evaporator 37 by closing the refrigerant passage. That is, the second expansion valve 36 combines the functions of a pressure reducing unit that reduces the pressure of the refrigerant and a refrigerant circuit switching unit that switches between refrigerant circuits. The second expansion valve 36 is an example of a pressure reducing unit.

[0070] The outlet of the second expansion valve 36 is connected to the refrigerant inlet side of the second evaporator 37. The second evaporator 37 functions as a heat absorber that absorbs heat from the low-pressure refrigerant reduced in pressure by the second expansion valve 36. The heat absorbed by the second evaporator 37 may be the air supplied to the rear seats of the passenger compartment, or it may be the heat transfer medium of a heat transfer medium circuit different from the first heat transfer medium circuit 10 and the second heat transfer medium circuit 20.

[0071] As shown in Figure 1, one refrigerant inlet side of the refrigerant confluence section 33b is connected to the refrigerant outlet of the first evaporator 35. The other refrigerant inlet side of the refrigerant confluence section 33b is connected to the refrigerant outlet side of the second evaporator 37. Here, the refrigerant confluence section 33b has a three-way joint structure similar to the refrigerant branch section 33a, with two of its three inlet / outlet ports serving as refrigerant inlets and the remaining one as a refrigerant outlet.

[0072] Therefore, the refrigerant confluence section 33b is a confluence section that combines the flow of refrigerant discharged from the first evaporator 35 and the flow of refrigerant discharged from the second evaporator 37. The suction port side of the compressor 31 is connected to the refrigerant outlet of the refrigerant confluence section 33b.

[0073] With the refrigeration cycle 30 configured in this way, the amount of heat released in the refrigerant heat exchanger 32 can be adjusted by controlling the operation of the compressor 31, the first expansion valve 34, and the second expansion valve 36. Therefore, in the vehicle air conditioning system 1, the heat generated by the second heat source 21 can be used to heat the second heat medium to a desired temperature.

[0074] Next, the interior air conditioning unit 50, which constitutes the vehicle air conditioning system 1, will be described with reference to Figure 2. The interior air conditioning unit 50 is a unit in the vehicle air conditioning system 1 that blows air whose temperature has been adjusted by the refrigeration cycle 30 to an appropriate location in the vehicle interior. The interior air conditioning unit 50 is located inside the instrument panel at the very front of the vehicle interior.

[0075] The interior air conditioning unit 50 is constructed by housing an interior blower 52, a first evaporator 35, a heater core 23, etc., in an air passage formed inside the air conditioning case 51 that forms its outer shell. The air conditioning case 51 forms an air passage for the blown air supplied to the vehicle interior. The air conditioning case 51 is molded from a resin (specifically, polypropylene) that has a certain degree of elasticity and excellent strength.

[0076] As shown in Figure 2, an internal / external air switching device 53 is located at the upstream end of the airflow path of the air conditioning case 51. The internal / external air switching device 53 switches between introducing internal air (inside the vehicle) and outside air (outside the vehicle) into the air conditioning case 51.

[0077] The internal / external air switching device 53 continuously adjusts the opening area of ​​the internal air inlet for introducing internal air and the external air inlet for introducing external air into the air conditioning case 51 using the internal / external air switching door, thereby changing the ratio of the internal air intake volume to the external air intake volume. The internal / external air switching door is driven by an electric actuator for the internal / external air switching door. The operation of this electric actuator is controlled by a control signal output from the control device 60.

[0078] An indoor blower 52 is positioned downstream of the airflow from the indoor / outdoor air switching device 53. The indoor blower 52 is an electric blower in which a centrifugal multi-blade fan is driven by an electric motor. The indoor blower 52 blows the air drawn in via the indoor / outdoor air switching device 53 into the vehicle interior. The rotational speed (i.e., blowing capacity) of the indoor blower 52 is controlled by a control voltage output from the control device 60.

[0079] The first evaporator 35 and the heater core 23 are arranged in this order with respect to the airflow of the indoor blower 52, downstream of the airflow. In other words, the first evaporator 35 is positioned upstream of the heater core 23 in the airflow. Therefore, in the indoor air conditioning unit 50 of the vehicle air conditioning system 1, at least a portion of the air that has passed through the first evaporator 35 can be heated by the heater core 23.

[0080] Furthermore, a cold air bypass passage 55 is formed inside the air conditioning case 51. The cold air bypass passage 55 is an air passage that directs the blown air that has passed through the first evaporator 35 downstream, bypassing the heater core 23.

[0081] An air mix door 54 is positioned downstream of the blown airflow of the first evaporator 35 and upstream of the blown airflow of the heater core 23. The air mix door 54 adjusts the ratio of the airflow that passes through the heater core 23 and the airflow that passes through the cold air bypass passage 55 from the blown air after it has passed through the first evaporator 35.

[0082] The air mix door 54 is driven by an electric actuator for driving the air mix door. The operation of this electric actuator is controlled by a control signal output from the control device 60.

[0083] Furthermore, a mixing space is provided downstream of the airflow of the heater core 23. In the mixing space, the air heated by the heater core 23 and the air that has passed through the cold air bypass passage 55 and is not heated by the heater core 23 are mixed.

[0084] Furthermore, at the downstream end of the airflow path of the air conditioning case 51, there is an opening for blowing the mixed air (conditioned air) into the vehicle interior. This opening includes a face opening, a foot opening, and a defroster opening (none of which are shown).

[0085] The face opening is an opening that blows conditioned air towards the upper body of the occupants inside the vehicle. The foot opening is an opening that blows conditioned air towards the occupants' feet. The defroster opening is an opening that blows conditioned air towards the inner surface of the front window glass of the vehicle.

[0086] These face openings, foot openings, and defroster openings are connected to face outlets, foot outlets, and defroster outlets (none of which are shown) located inside the vehicle cabin, via ducts that form air passages.

[0087] Therefore, the air mix door 54 adjusts the ratio of the airflow passing through the heater core 23 to the airflow passing through the cold air bypass passage 55, thereby adjusting the temperature of the conditioned air mixed in the mixing space. This also adjusts the temperature of the air blown into the passenger compartment from each outlet (conditioned air).

[0088] Furthermore, a face door, a foot door, and a defroster door (none of which are shown) are positioned upstream of the airflow through the face opening, foot opening, and defroster opening, respectively. The face door adjusts the opening area of ​​the face opening. The foot door adjusts the opening area of ​​the foot opening. The defroster door adjusts the opening area of ​​the defroster opening.

[0089] These face doors, foot doors, and defroster doors constitute a blowing mode switching device that switches the air outlets from which conditioned air is blown. The face doors, foot doors, and defroster doors are connected via a linkage mechanism or the like to an electric actuator for driving the air outlet mode door, and are rotated in conjunction with it. The operation of this electric actuator is controlled by a control signal output from the control device 60.

[0090] Next, an overview of the control system of the vehicle air conditioning system 1 will be explained using Figure 3. The control device 60 consists of a well-known microcomputer including a CPU, ROM, and RAM, and its peripheral circuits. The control device 60 performs various calculations and processes based on the air conditioning control program stored in the ROM, and controls the operation of various controlled devices connected to the output side. The control device 60 is an example of a control unit.

[0091] The various controlled devices include a first heat transfer pump 12, a four-way valve 16, a second heat transfer pump 22, and a three-way heat transfer valve 25. Furthermore, the various controlled devices also include a compressor 31, a first expansion valve 34, a second expansion valve 36, an indoor blower 52, an indoor / outdoor air switching device 53, an air mix door 54, and the like.

[0092] As shown in Figure 3, various control sensors are connected to the input side of the control device 60. These control sensors include an indoor temperature sensor 62a, an outdoor temperature sensor 62b, and a solar radiation sensor 62c. Other control sensors include a high-pressure sensor 62d, a first evaporator temperature sensor 62f, a second evaporator temperature sensor 62g, an air conditioning air temperature sensor 62e, an equipment temperature sensor, and a battery temperature sensor.

[0093] The interior temperature sensor 62a is an interior temperature detection unit that detects the interior temperature Tr, which is the temperature inside the vehicle. The exterior temperature sensor 62b is an exterior temperature detection unit that detects the exterior temperature Tam, which is the temperature outside the vehicle. The solar radiation sensor 62c is a solar radiation detection unit that detects the amount of solar radiation As that is irradiated into the vehicle.

[0094] The high-pressure sensor 62d is a high-pressure detection unit that detects the high-pressure pressure Pd, which is the pressure of the high-pressure refrigerant discharged from the compressor 31. The air conditioning air temperature sensor 62e is an air conditioning air temperature detection unit that detects the temperature TAV of the discharged air blown from the mixing space into the vehicle interior.

[0095] The first evaporator temperature sensor 62f is a refrigerant temperature detection unit that detects the refrigerant evaporation temperature in the first evaporator 35. The second evaporator temperature sensor 62g is a refrigerant temperature detection unit that detects the refrigerant evaporation temperature in the second evaporator 37.

[0096] Furthermore, multiple heat transfer medium temperature sensors are connected to the input side of the control device 60 to detect the temperature of the heat transfer medium in the first heat transfer medium circuit 10 and the second heat transfer medium circuit 20. The multiple heat transfer medium temperature sensors include the first heat transfer medium temperature sensor 62h and the second heat transfer medium temperature sensor 62i.

[0097] The first heat transfer medium temperature sensor 62h is located at the outlet of the heat transfer medium passage in the engine 11a and detects the temperature of the first heat transfer medium flowing out from the first heat source 11. The second heat transfer medium temperature sensor 62i is located at the outlet of the heat transfer medium passage 32a in the heat transfer medium refrigerant heat exchanger 32 and detects the temperature of the second heat transfer medium flowing out from the heat transfer medium refrigerant heat exchanger 32, which is a component of the second heat source 21.

[0098] The vehicle air conditioning system 1 performs control to achieve heating operation that effectively utilizes the first heat source 11 and the second heat source 21, based on the detection results of the first heat medium temperature sensor 62h and the second heat medium temperature sensor 62i. The details of this heating operation control will be explained later with reference to the drawings.

[0099] Furthermore, an operation panel 61, located near the instrument panel at the front of the vehicle interior, is connected to the input side of the control device 60. Operation signals from various operation switches provided on this operation panel 61 are input to the control device 60.

[0100] The various operation switches provided on the control panel 61 include, specifically, an auto switch, an air conditioner switch, an airflow setting switch, a temperature setting switch, and the like. The auto switch is an operation switch that sets or cancels the automatic control operation of the refrigeration cycle 30.

[0101] The air conditioning switch is an operating switch that requests the cooling of the blown air by the first evaporator 35. The airflow setting switch is an operating switch that is operated when manually setting the airflow of the indoor blower 52. The temperature setting switch is an operating switch that sets the target temperature Tset inside the vehicle.

[0102] Furthermore, the control device 60 of this embodiment is configured with an integrated control unit that controls various controlled devices connected to its output side. Therefore, the configuration (i.e., hardware and software) that controls the operation of each controlled device constitutes the control unit that controls the operation of each controlled device.

[0103] For example, in the control device 60, when switching from a state where the second heat source 21 is being used for heating to a state where at least the first heat source 11 is being used for heating, a configuration that performs control to effectively utilize the first heat source 11 and the second heat source 21 to achieve stable heating performance corresponds to the first switching control unit 60a.

[0104] Furthermore, within the control device 60, the configuration that controls the system to effectively utilize both the first heat source 11 and the second heat source 21 to achieve stable heating performance when heating is performed using the second heat source 21 from a state where the first heat source 11 is operating corresponds to the second switching control unit 60b.

[0105] Next, the types of circulation modes of the first heat transfer medium in the first heat transfer medium circuit 10 of the vehicle air conditioning system 1 will be explained with reference to Figures 4 to 7. The circulation modes of the first heat transfer medium in the first heat transfer medium circuit 10 of the vehicle air conditioning system 1 include the first to fourth circulation modes.

[0106] The first circulation mode in the first heat transfer medium circuit 10 is a circulation mode in which the first heat transfer medium circulates via the first heat source 11, the heat transfer medium heat exchanger 13, and the outside air radiator 14. In the first circulation mode of the first heat transfer medium circuit 10, the control device 60 connects the inlet and outlet on the engine 11a side with the inlet and outlet on the heat transfer medium heat exchanger 13 side of the four-way valve 16, while closing the inlet and outlet on the branching section 17 side with the inlet and outlet on the merging section 18 side. The control device 60 also causes the first heat transfer medium pump 12 to discharge the first heat transfer medium at a predetermined discharge capacity.

[0107] As shown in Figure 4, in the first circulation mode of the first heat transfer medium circuit 10, the first heat transfer medium circulates in the following order: first heat transfer medium pump 12, first heat source 11 (engine 11a), four-way valve 16, heat transfer medium heat exchanger 13, junction 18, outside air radiator 14, and first heat transfer medium pump 12.

[0108] This allows the heat from the engine 11a, which is the first heat source 11, to be transferred to the second heat medium via the first heat medium by circulating the first heat medium through the heat exchanger 13. In addition, by circulating the first heat medium through the outside air radiator 14, the heat from the engine 11a, which is the first heat source 11, can be released to the outside air via the first heat medium.

[0109] The second circulation mode in the first heat transfer medium circuit 10 is a circulation mode in which the first heat transfer medium circulates via the first heat source 11 and the outside air radiator 14, while simultaneously bypassing the heat transfer medium heat exchanger 13. In the second circulation mode of the first heat transfer medium circuit 10, the control device 60 connects the inlet and outlet on the engine 11a side with the inlet and outlet on the confluence section 18 side of the four-way valve 16, while closing the inlet and outlet on the heat transfer medium heat exchanger 13 side with the inlet and outlet on the branch section 17 side. The control device 60 also causes the first heat transfer medium pump 12 to discharge the first heat transfer medium at a predetermined discharge capacity.

[0110] As shown in Figure 5, in the second circulation mode of the first heat transfer medium circuit 10, the first heat transfer medium circulates in the following order: first heat transfer medium pump 12, first heat source 11 (engine 11a), four-way valve 16, bypass flow path 15, confluence section 18, outside air radiator 14, and first heat transfer medium pump 12.

[0111] As a result, by circulating the first heat transfer medium through the heat transfer medium heat exchanger 13, the heat from the engine 11a, which is the first heat source 11, can be released to the outside air via the first heat transfer medium without being transferred to the second heat transfer medium via the first heat transfer medium.

[0112] The third circulation mode in the first heat transfer medium circuit 10 is a circulation mode in which a portion of the first heat transfer medium that has passed through the outside air radiator 14 and the first heat source 11 passes through the heat transfer medium heat exchanger 13, while the remaining portion circulates by bypassing the heat transfer medium heat exchanger 13. In the third circulation mode of the first heat transfer medium circuit 10, the control device 60 connects the inlet and outlet on the engine 11a side, the inlet and outlet on the heat transfer medium heat exchanger 13 side, and the inlet and outlet on the confluence section 18 side of the four-way valve 16, while closing the inlet and outlet on the branch section 17 side. The control device 60 also causes the first heat transfer medium pump 12 to discharge the first heat transfer medium at a predetermined discharge capacity.

[0113] As shown in Figure 6, in the third circulation mode of the first heat transfer medium circuit 10, the first heat transfer medium circulates in the following order: first heat transfer medium pump 12, first heat source 11 (engine 11a), four-way valve 16, heat transfer medium heat exchanger 13, confluence section 18, outside air radiator 14, and first heat transfer medium pump 12. At the same time, the first heat transfer medium circulates in the following order: first heat transfer medium pump 12, first heat source 11 (engine 11a), four-way valve 16, bypass flow path 15, confluence section 18, outside air radiator 14, and first heat transfer medium pump 12.

[0114] This allows a portion of the first heat transfer medium to flow through the heat transfer medium heat exchanger 13, thereby transferring some of the heat from the engine 11a, which is the first heat source 11, to the second heat transfer medium via the first heat transfer medium. Furthermore, by circulating the remaining portion of the first heat transfer medium in a way that bypasses the heat transfer medium heat exchanger 13, the amount of heat transferred to the second heat transfer medium via the first heat transfer medium can be adjusted.

[0115] Furthermore, the fourth circulation mode in the first heat transfer medium circuit 10 is a circulation mode in which the first heat transfer medium circulates via the heat transfer medium heat exchanger 13 and the outside air radiator 14. In the fourth circulation mode of the first heat transfer medium circuit 10, the control device 60 connects the inlet and outlet on the branch section 17 side with the inlet and outlet on the heat transfer medium heat exchanger 13 side of the four-way valve 16, while closing the inlet and outlet on the engine 11a side with the inlet and outlet on the junction section 18 side. In addition, the control device 60 causes the first heat transfer medium pump 12 to discharge the first heat transfer medium at a predetermined discharge capacity.

[0116] As shown in Figure 7, in the fourth circulation mode of the first heat transfer medium circuit 10, the first heat transfer medium circulates in the following order: first heat transfer medium pump 12, branch section 17, four-way valve 16, heat transfer medium heat exchanger 13, junction section 18, outside air radiator 14, and first heat transfer medium pump 12.

[0117] This allows the heat contained in the first heat transfer medium, which has undergone heat exchange with the second heat transfer medium in the heat transfer medium heat exchanger 13, to be released to the outside air in the outside air radiator 14.

[0118] Next, the first switching control in the vehicle air conditioning system 1 will be explained with reference to Figures 8 and 9. As described above, the first switching control in the vehicle air conditioning system 1 is performed when the vehicle switches from a state in which the second heat source 21 is used for heating to a state in which at least the first heat source 11 is used for heating.

[0119] For example, the first switching control applies to a case where the system switches from a state in which the blown air is heated using the heat pumped up by the refrigeration cycle 30 to a state in which the blown air is heated using at least the waste heat from the engine 11a. Therefore, a case in which the system switches to a state in which the blown air is heated using both the waste heat from the engine 11a and the heat pumped up by the refrigeration cycle 30 is also included in the first switching control.

[0120] In the first switching control, a transition state is interposed between an initial state, which indicates that the second heat source 21 is being used for heating, and a switching completion state, which indicates that at least the first heat source 11 is being used for heating.

[0121] First, an example of the initial state of the first switching control will be explained with reference to Figure 8. As shown in Figure 8, in the initial state of the first switching control, the first heat transfer medium circuit 10 circulates the first heat transfer medium in the second circulation mode. In the second circulation mode, the first heat transfer medium that flows out from the engine 11a bypasses the heat transfer medium heat exchanger 13 and circulates through the outside air radiator 14. Therefore, the waste heat from the engine 11a is not transferred to the second heat transfer medium in the heat transfer medium heat exchanger 13, but is instead released to the outside air in the outside air radiator 14.

[0122] Furthermore, in the initial state of the first switching control, the second heat transfer medium circulates in the following order: second heat transfer medium pump 22, heat transfer medium heat exchanger 13, heater core 23, heat transfer medium refrigerant heat exchanger 32, and second heat transfer medium pump 22. Here, in the initial state of the first switching control, the refrigeration cycle 30 is operating, and the heat absorbed in the first evaporator 35 and the second evaporator 37 is released to the second heat transfer medium by the heat transfer medium refrigerant heat exchanger 32. Therefore, in the initial state of the first switching control, heating of the blown air using the refrigeration cycle 30, which is the second heat source 21, as the heat source is achieved.

[0123] Next, the transition state in the first switching control will be described with reference to the drawings. The control device 60 changes the vehicle air conditioning system 1 to the transition state when the conditions for heating the blown air using at least the second heat source 21 are met while the blown air is being heated using the first heat source 11.

[0124] In the transition state of the first switching control, the flow of the first heat medium into the heat exchanger 13 is delayed until the temperature of the first heat medium detected by the first heat medium temperature sensor 62h rises above a predetermined reference value. Specifically, the control device 60 cancels the transition state and changes to the switching completion state when the temperature of the first heat medium becomes equal to or higher than the temperature of the second heat medium, or when the elapsed time since the engine 11a, which is the first heat source 11, started has exceeded a predetermined value.

[0125] Next, the switching completion state in the first switching control will be explained with reference to Figure 9. Figure 9 shows an example of the switching completion state in the first switching control, in which the blown air is heated using the waste heat from the engine 11a, which is the first heat source 11, and the heat originating from the refrigeration cycle 30, which is the second heat source 21.

[0126] In the first switching control, when the temperature of the first heat transfer medium becomes equal to or higher than the temperature of the second heat transfer medium, the control device 60 controls the first heat transfer medium circuit 10 so that it circulates at least through the engine 11a and the heat transfer medium heat exchanger 13 in order to change from the transition state to the switching completion state. For example, as shown in Figure 9, the control device 60 switches the first heat transfer medium circuit 10 from the second circulation mode to the first circulation mode.

[0127] At this time, in the second heat transfer medium circuit, the second heat transfer medium circulates through the heat transfer medium heat exchanger 13, the heater core 23, and the refrigerant heat exchanger 32, and the refrigeration cycle 30 is also operating. Therefore, in the switched-out state, the heat transfer medium heat exchanger 13 can transfer heat from the first heat transfer medium originating from the engine 11a to the second heat transfer medium, and the heat transfer medium refrigerant heat exchanger 32 can transfer heat from the refrigerant of the refrigeration cycle 30 to the second heat transfer medium. Then, the second heat transfer medium heated in the heat transfer medium heat exchanger 13 and the refrigerant heat exchanger 32 flows through the heater core 23, so the vehicle air conditioning system 1 in the switched-out state can achieve heating using the first heat source 11 and the second heat source 21.

[0128] When the second heat source 21 is being used for heating, and then at least when the first heat source 11 is being used for heating, if the temperature of the first heat medium is lower than that of the second heat medium, it is expected that the temperature of the second heat medium will decrease due to heat exchange in the heat medium heat exchanger 13. In that case, the blown air in the heater core 23 will be heated by the heat contained in the second heat medium, and therefore, when the temperature of the first heat medium is lower than that of the second heat medium, the heating performance of the vehicle air conditioning system 1 will decrease.

[0129] Taking this into consideration, the first switching control of the vehicle air conditioning system 1 includes a transition state between the initial state and the switching completion state in which the system waits for the first heat medium to flow into the heat exchanger 13 until the temperature of the first heat medium becomes higher than the temperature of the second heat medium. As a result, even if the first heat medium flows into the heat exchanger 13, the temperature of the second heat medium will not decrease, so the vehicle air conditioning system 1 can effectively utilize the first heat source 11 and the second heat source 21 to provide stable heating performance.

[0130] In the transition state of the first switching control, the first heat transfer medium circuit 10 was set to the second circulation state in order to wait for the first heat transfer medium to flow into the heat transfer medium heat exchanger 13, but the system is not limited to this configuration. It is sufficient to suppress the flow of the first heat transfer medium into the heat transfer medium heat exchanger 13, and for example, it is possible to stop the circulation of the first heat transfer medium by stopping the first heat transfer medium pump 12 until the temperature of the first heat transfer medium meets predetermined conditions.

[0131] Next, the second switching control in the vehicle air conditioning system 1 will be explained with reference to Figures 10 to 12. As described above, the second switching control in the vehicle air conditioning system 1 is performed when switching from a state where the first heat source 11 is operating to a state where heating is performed using the second heat source 21.

[0132] For example, the second switching control applies to a situation where the system switches from a state where the engine 11a is running and generating waste heat to a state where the heat pumped up by the refrigeration cycle 30 is used to heat the blown air.

[0133] In the second switching control, a transition state is interposed between the initial state, which indicates that the second heat source 21 is in operation, and the switching completion state, which indicates that the first heat source 11 is being used for heating on its own.

[0134] First, the initial state in the second switching control will be explained with reference to Figure 10. As shown in Figure 10, in the initial state of the second switching control, the engine 11a is running, and the first heat transfer fluid circuit 10 is controlled to enter the first circulation mode. In the initial state of the second switching control, the second heat transfer fluid in the second heat transfer fluid circuit 20 is not circulating, and the refrigeration cycle 30 as the second heat source 21 is not operating.

[0135] Therefore, in the initial state of the second switching control, the first heat transfer medium is heated by the waste heat from the running engine 11a and flows into the heat transfer medium heat exchanger 13. Since the second heat transfer medium is not circulating in the second heat transfer medium circuit 20, the first heat transfer medium flows towards the outside air radiator 14 without releasing much heat to the second heat transfer medium in the heat transfer medium heat exchanger 13. In the outside air radiator 14, the heat contained in the first heat transfer medium is released to the outside air. In other words, in the initial state of the second switching control, the waste heat generated by the running engine 11a is released to the outside air in the outside air radiator 14 via the first heat transfer medium.

[0136] Next, the transition state in the second switching control will be explained with reference to Figure 11. When the control device 60 is in a state where the engine 11a, which is the first heat source 11, is running, and it is decided to stop the engine 11a and heat the blown air using the second heat source 21, the control device 60 changes the vehicle air conditioning system 1 to a transition state. A specific example of the transition state related to the second switching control is when a hybrid vehicle transitions from an operating mode in which it runs using the driving force generated by the engine 11a to an operating mode in which it runs by driving the electric motor for traction with the power of the battery, and at the same time the interior of the vehicle is heated.

[0137] In the transition state of the second switching control, the control device 60 controls the first heat transfer medium circuit 10 to maintain the first circulation mode, similar to the initial state. At this stage of transitioning to the transition state, the engine 11a, which is the first heat source 11, is stopped. Therefore, in the first heat transfer medium circuit 10 in the transition state, the first heat transfer medium, which has already been heated by the waste heat of the engine 11a, is circulating.

[0138] The control device 60 then drives the second heat transfer pump 22 with respect to the second heat transfer circuit 20, and controls the second heat transfer medium to circulate in the following order: second heat transfer pump 22, heat transfer heat exchanger 13, heater core 23, heat transfer refrigerant heat exchanger 32, and second heat transfer pump 22. At this time, the control device 60 operates the refrigeration cycle 30, which is the second heat source 21, and releases the heat absorbed in the first evaporator 35 and the second evaporator 37 to the second heat transfer medium in the heat transfer refrigerant heat exchanger 32.

[0139] In other words, in the transition state of the second switching control, the first heat transfer medium is circulated in the first heat transfer medium circuit 10 via the heat transfer medium heat exchanger 13, and the second heat transfer medium is circulated in the second heat transfer medium circuit 20 via the heat transfer medium heat exchanger 13 and the heat transfer medium refrigerant heat exchanger 32. Therefore, in the transition state of the second switching control, the second heat transfer medium in the second heat transfer medium circuit 20 is heated in the heat transfer medium refrigerant heat exchanger 32 by the heat pumped up by the refrigeration cycle 30, and in the heat transfer medium heat exchanger 13 it is heated by the first heat transfer medium and the residual heat of the engine 11a.

[0140] The transition state in the second switching control continues until the temperature of the second heat medium detected by the second heat medium temperature sensor 62i rises above a predetermined value. The predetermined value is determined, for example, by the temperature of the first heat medium detected by the first heat medium temperature sensor 62h, and when the temperature of the second heat medium rises above the temperature of the first heat medium, the system transitions from the transition state to the switching completion state.

[0141] In other words, in the transition state of the second switching control, the second heat transfer medium can be heated to the same level as the first heat transfer medium by using the refrigeration cycle 30, which is the second heat source 21, in combination with the residual heat of the first heat transfer medium and the engine 11a.

[0142] Next, the switching completion state in the second switching control will be explained with reference to Figure 12. In the second switching control, when the temperature of the second heat transfer medium becomes equal to or higher than the temperature of the first heat transfer medium, the control device 60 stops driving the first heat transfer medium pump 12 and stops the circulation of the first heat transfer medium in the first heat transfer medium circuit 10 in order to change from the transition state to the switching completion state.

[0143] At this time, when the second switching control is complete, the refrigeration cycle 30, which is the second heat source 21, is operating, and in the second heat transfer medium circuit 20, the second heat transfer medium circulates through the heat transfer medium heat exchanger 13, the heater core 23, and the heat transfer medium refrigerant heat exchanger 32. As described above, since the circulation of the first heat transfer medium in the first heat transfer medium circuit 10 is stopped, when the switching is complete, the vehicle air conditioning system 1 provides heating to the vehicle interior using the second heat source 21.

[0144] In the vehicle air conditioning system 1, if the refrigeration cycle 30, which is the second heat source 21, is stopped, and the circulation of the second heat medium in the second heat medium circuit 20 is also stopped, it is assumed that the second heat medium is at a relatively low temperature. From this state, even if the refrigeration cycle 30 is driven and heating of the vehicle interior is started via the second heat medium, it is assumed that sufficient heating capacity cannot be obtained until the temperature of the second heat medium rises.

[0145] Taking this into consideration, the second switching control of the vehicle air conditioning system 1 includes a transition state between the initial state in which the first heat source 11 is operating and the switching completion state. In the transition state of the second switching control, the first heat medium and the second heat medium are exchanged in the heat medium heat exchanger 13 until the temperature of the second heat medium becomes higher than the temperature of the first heat medium. That is, in addition to the heat generated by the second heat source 21, the residual heat from the first heat source 11 (i.e., the engine 11a) can be added to the second heat medium via the first heat medium.

[0146] This shortens the time required for the temperature of the second heat transfer medium to rise, allowing the vehicle air conditioning system 1 to effectively utilize the first heat source 11 and the second heat source 21 to achieve stable heating performance when starting heating using the second heat source 21.

[0147] As described above, the vehicle air conditioning system 1 according to the first embodiment includes a first heat transfer medium circuit 10, a second heat transfer medium circuit 20, and a control device 60, as shown in Figure 1 and the like. The first heat transfer medium circuit 10 circulates a first heat transfer medium via the engine 11a, which serves as the first heat source 11. The second heat transfer medium circuit 20 circulates a second heat transfer medium via the components of the refrigeration cycle 30 (heat transfer medium refrigerant heat exchanger 32), which serves as the second heat source 21, and a heater core 23. The heat transfer medium heat exchanger 13 is located in the first heat transfer medium circuit 10 and the second heat transfer medium circuit 20, and exchanges heat between the first heat transfer medium circulating in the first heat transfer medium circuit 10 and the second heat transfer medium circulating in the second heat transfer medium circuit 20. The control device 60 controls the operation of the first heat transfer medium circuit 10 and the second heat transfer medium circuit 20.

[0148] With the vehicle air conditioning system 1 configured in this way, the first heat medium, which recovers the waste heat from the engine 11a, and the second heat medium, which recovers the heat generated in the refrigeration cycle 30, can exchange heat in the heat medium heat exchanger 13. In other words, the vehicle air conditioning system 1 can appropriately utilize the amount of heat related to the waste heat from the engine 11a and the amount of heat generated in the refrigeration cycle 30 to compensate for any surplus or deficit, thereby stabilizing the heating performance of the vehicle air conditioning system 1.

[0149] Furthermore, the vehicle air conditioning system 1 has a refrigeration cycle 30 as a second heat source 21. The refrigeration cycle 30 includes a compressor 31, a refrigerant heat exchanger 32, a first expansion valve 34 and a second expansion valve 36 as a pressure reducing section, and a first evaporator 35 and a second evaporator 37 as evaporators. The amount of heat applied to the second heat transfer medium can be adjusted by adjusting the refrigerant discharge capacity of the compressor 31 and the amount of refrigerant pressure reduction in the pressure reducing section of the refrigeration cycle 30.

[0150] Therefore, with the vehicle air conditioning system 1, by employing a refrigeration cycle 30 as the second heat source 21, it becomes possible to efficiently heat the second heat transfer medium, thereby improving the heating performance and power saving capabilities of the vehicle air conditioning system 1.

[0151] As shown in Figure 1, the vehicle air conditioning system 1 includes a heat quantity adjustment unit 45 that adjusts the amount of heat supplied to the heat exchanger 13, and a heat dissipation unit 46 that releases the amount of heat that was not supplied to the heat exchanger 13 by the heat quantity adjustment unit 45.

[0152] This allows the vehicle air conditioning system 1 to balance the heat generated by the first heat source 11 and the second heat source 21 with the amount of heat required by the heater core 23. For example, if the heat generated by the first heat source 11 and the second heat source 21 is in excess of the amount of heat required by the heater core 23, the vehicle air conditioning system 1 controls the heat quantity adjustment unit 45 to release the excess heat from the heat dissipation unit 46 and supply the appropriate amount of heat to the heater core 23.

[0153] As shown in Figure 1, the first heat transfer medium circuit 10 of the vehicle air conditioning system 1 is equipped with a bypass flow path 15 and a four-way valve 16 as a heat quantity adjustment unit 45, and an outside air radiator 14 as a heat dissipation unit 46.

[0154] As shown in Figures 4 to 7, the vehicle air conditioning system 1 can adjust the amount of heat supplied to the heat exchanger 13 and the amount of heat released to the outside air by the outside air radiator 14 by controlling the operation of the four-way valve 16. Since the amount of heat supplied to the heat exchanger 13 is strongly correlated with the amount of heat supplied to the heater core 23 via the second heat supply, it is possible to appropriately adjust the amount of heat supplied to the heater core 23 by controlling the operation of the four-way valve 16.

[0155] Furthermore, the second heat transfer medium circuit 20 of the vehicle air conditioning system 1 is equipped with a heat transfer medium bypass channel 24 and a heat transfer medium three-way valve 25 as a heat quantity adjustment unit 45, and a heat transfer medium radiator 27 as a heat dissipation unit 46.

[0156] Therefore, the vehicle air conditioning system 1 can adjust the flow rate of the second heat transfer medium flowing into the heater core 23 and the flow rate of the second heat transfer medium flowing to the heat transfer medium bypass channel 24 and the heat transfer medium radiator 27 by controlling the operation of the three-way valve 25 of the heat transfer medium. As a result, the vehicle air conditioning system 1 can appropriately adjust the amount of heat supplied to the heater core 23 by controlling the operation of the three-way valve 25 of the heat transfer medium.

[0157] As shown in Figures 4 and 5, the vehicle air conditioning system 1 can switch between a first circulation mode and a second circulation mode for the circulation of the first heat transfer medium in the first heat transfer medium circuit 10. The first circulation mode is a mode in which the first heat transfer medium circulates via the outside air radiator 14, the engine 11a, and the heat transfer medium heat exchanger 13, while the second circulation mode is a mode in which the first heat transfer medium circulates via the engine 11a and the outside air radiator 14 without going through the heat transfer medium heat exchanger 13.

[0158] Therefore, the vehicle air conditioning system 1 can select the destination for the exhaust heat from the engine 11a, which is the first heat source 11, from the heat exchanger 13 and the outside air radiator 14 by using a first circulation mode and a second circulation mode as the circulation mode of the first heat transfer medium in the first heat transfer medium circuit 10. This allows the vehicle air conditioning system 1 to control the amount of heat exchanged between the first heat transfer medium and the second heat transfer medium in the heat exchanger 13. In other words, the vehicle air conditioning system 1 can effectively utilize the amount of heat originating from the first heat source 11 in the first heat transfer medium and the amount of heat originating from the second heat source 21 in the second heat transfer medium to stabilize the heating performance in the heater core 23.

[0159] Furthermore, as shown in Figure 6, the vehicle air conditioning system 1 can switch to a third circulation mode in addition to the first and second circulation modes as the circulation mode of the first heat medium in the first heat medium circuit 10. In the third circulation mode, a portion of the first heat medium that has passed through the outside air radiator 14 and the engine 11a passes through the heat medium heat exchanger 13, while the remaining first heat medium circulates by bypassing the heat medium heat exchanger 13.

[0160] As a result, the vehicle air conditioning system 1 can adopt a third circulation mode as the circulation mode of the first heat medium in the first heat medium circuit 10, thereby releasing a portion of the exhaust heat from the engine 11a to the second heat medium and releasing the remaining heat into the outside air. In other words, the vehicle air conditioning system 1 can accurately adjust the distribution of the amount of heat originating from the first heat source 11 in the first heat medium and the amount of heat originating from the second heat source 21 in the second heat medium, thereby stabilizing the heating performance in the heater core 23.

[0161] Furthermore, as shown in Figure 7, the vehicle air conditioning system 1 can switch to a fourth circulation mode in addition to the first to third circulation modes as the circulation mode of the first heat transfer medium in the first heat transfer medium circuit 10. The fourth circulation mode is a mode in which the first heat transfer medium circulates via the heat transfer medium heat exchanger 13 and the outside air radiator 14 without going through the engine 11a.

[0162] As a result, the vehicle air conditioning system 1 can switch to the fourth circulation mode, thereby releasing the heat contained in the first heat medium, which has exchanged heat with the second heat medium in the heat medium heat exchanger 13, into the outside air. Furthermore, the vehicle air conditioning system 1 can switch the circulation mode of the first heat medium in the first heat medium circuit 10 to various circulation modes, thereby effectively utilizing the heat amount derived from the first heat source 11 and the heat amount derived from the second heat source 21 to stabilize heating performance.

[0163] As shown in Figure 1, in the second heat transfer medium circuit 20 of the vehicle air conditioning system 1, the heat transfer medium refrigerant heat exchanger 32 is located upstream of the heat transfer medium heat exchanger 13 with respect to the flow of the second heat transfer medium. The heat transfer medium refrigerant heat exchanger 32 is one of the components of the refrigeration cycle 30, which is the second heat source 21, and is a heat exchanger that releases the heat drawn up by the refrigeration cycle 30 to the second heat transfer medium.

[0164] In the second heat transfer medium circuit 20, by arranging the heat transfer medium refrigerant heat exchanger 32 upstream of the heat transfer medium heat exchanger 13, the amount of heat to be released from the first heat transfer medium to the second heat transfer medium in the heat transfer medium heat exchanger 13 can be determined. As a result, the vehicle air conditioning system 1 can compensate for any shortfall in heating performance with heat originating from the first heat source 11, thereby efficiently stabilizing heating performance.

[0165] Furthermore, in the second heat transfer medium circuit 20 of the vehicle air conditioning system 1, the heater core 23 is positioned upstream of the heat transfer medium refrigerant heat exchanger 32 with respect to the flow of the second heat transfer medium. As described above, the heat transfer medium refrigerant heat exchanger 32 is one of the components of the refrigeration cycle 30, which is the second heat source 21, and is a heat exchanger that releases the heat pumped up by the refrigeration cycle 30 to the second heat transfer medium.

[0166] Therefore, the second heat transfer medium of the second heat transfer medium circuit 20 flows into the heat transfer medium refrigerant heat exchanger 32 that constitutes the second heat source 21, after releasing heat to the heater core 23 to heat the blown air. In other words, the second heat transfer medium can be supplied to the second heat source 21 at the lowest possible temperature, so that the amount of heat generated in the second heat source 21 can be recovered efficiently.

[0167] Furthermore, if a refrigeration cycle 30 is used as the second heat source 21, and the amount of heat dissipated in the heat transfer medium refrigerant heat exchanger 32 cannot be secured, it is expected that a high-pressure abnormality will occur with respect to the refrigerant pressure of the refrigeration cycle 30. In this regard, since the second heat transfer medium can be circulated to the heat transfer medium refrigerant heat exchanger 32 at the lowest possible temperature, the vehicle air conditioning system 1 can suppress the occurrence of high-pressure abnormalities in the refrigeration cycle.

[0168] Furthermore, in the second heat transfer medium circuit 20 of the vehicle air conditioning system 1, the heat transfer medium heat exchanger 13 is positioned upstream of the heat transfer medium three-way valve 25, which functions as a branch to the heat transfer medium bypass flow path 24 with respect to the flow of the second heat transfer medium.

[0169] This allows the second heat transfer medium, which has exchanged heat with the first heat transfer medium in the heat transfer medium heat exchanger 13, to be circulated to the heat transfer medium bypass channel 24 and the heat transfer medium radiator 27 while maintaining its heat as much as possible. In other words, the vehicle air conditioning system 1 can maximize the amount of heat dissipated by the second heat transfer medium in the heat transfer medium radiator 27. For example, in the case of frost formation on the heat transfer medium radiator 27 in an environment where the outside air is cold and humid, adopting this configuration can improve the defrosting performance when the second heat transfer medium defrosts the heat transfer medium radiator 27.

[0170] Furthermore, in the vehicle air conditioning system 1, the first switching control is executed when the system switches from using the second heat source 21 for heating to using at least the first heat source 11 for heating. As shown in Figures 8 and 9, the first switching control interposes a transition state between an initial state, which indicates that the second heat source 21 is being used for heating, and a completed switching state, which indicates that at least the first heat source 11 is being used for heating.

[0171] In the transition state of the first switching control, the refrigeration cycle 30, which is the second heat source 21, is operated until the temperature of the first heat medium reaches or exceeds the temperature of the second heat medium, and the second heat medium is maintained to circulate in the second heat medium circuit 20 at least through the second heat source 21 and the heater core 23. At this time, the first heat medium circuit 10 circulates the first heat medium in the second circulation mode and waits for the first heat medium that has flowed through the first heat source 11 to flow into the heat medium heat exchanger 13. By transitioning from this transition state to the switching completion state shown in Figure 9, heating can be performed using at least the first heat source 11 once the temperature of the first heat medium has risen sufficiently.

[0172] Here, when switching from using the second heat source 21 for heating to using at least the first heat source 11 for heating, if the temperature of the first heat medium is lower than that of the second heat medium, it is assumed that the temperature of the second heat medium will decrease due to heat exchange in the heat medium heat exchanger 13. In that case, the blown air in the heater core 23 will be heated by the heat contained in the second heat medium, and therefore, when the temperature of the first heat medium is lower than that of the second heat medium, the heating performance of the vehicle air conditioning system 1 will decrease.

[0173] In this regard, the first switching control of the vehicle air conditioning system 1 intervenes in a transition state between the initial state and the completed switching state. Therefore, even if the first heat transfer medium flows into the heat transfer medium heat exchanger 13, the temperature of the second heat transfer medium does not decrease. Consequently, by performing the first switching control, the vehicle air conditioning system 1 can effectively utilize the first heat source 11 and the second heat source 21 to achieve stable heating performance.

[0174] In the vehicle air conditioning system 1, the second switching control is executed when switching from a state where the first heat source 11 is operating to a state where heating is performed using the second heat source 21. As shown in Figures 10 to 12, the second switching control interposes a transition state between an initial state, which indicates that the second heat source 21 is in operation, and a completed switching state, which indicates that the first heat source 11 is being used for heating alone.

[0175] In the transition state of the second switching control, the first heat transfer medium is circulated in the first heat transfer medium circuit 10 via the heat transfer medium heat exchanger 13, and the second heat transfer medium is circulated in the second heat transfer medium circuit 20 via the heat transfer medium heat exchanger 13 and the heat transfer medium refrigerant heat exchanger 32. Therefore, in the transition state of the second switching control, the second heat transfer medium in the second heat transfer medium circuit 20 is heated by the heat drawn up by the refrigeration cycle 30 in the heat transfer medium refrigerant heat exchanger 32, and is also heated in the heat transfer medium heat exchanger 13 by the residual heat of the first heat transfer medium and the engine 11a. The transition state in the second switching control is continued until the temperature of the second heat transfer medium detected by the second heat transfer medium temperature sensor 62i rises above a predetermined value.

[0176] In the vehicle air conditioning system 1, if the refrigeration cycle 30, which is the second heat source 21, is stopped, and the circulation of the second heat medium in the second heat medium circuit 20 is also stopped, it is assumed that the second heat medium will be at a relatively low temperature. From this state, even if the refrigeration cycle 30 is driven and heating of the vehicle interior is started via the second heat medium, it is assumed that sufficient heating capacity cannot be obtained until the temperature of the second heat medium rises.

[0177] In this regard, the second switching control of the vehicle air conditioning system 1 intervenes in a transition state between the initial state and the switching completion state, so that in addition to the heat generated by the second heat source 21, the residual heat of the first heat source 11 (i.e., the engine 11a) can be added to the second heat medium via the first heat medium. As a result, the period until the temperature of the second heat medium rises can be shortened, so that the vehicle air conditioning system 1 can effectively utilize the first heat source 11 and the second heat source 21 to achieve stable heating performance when starting heating using the second heat source 21.

[0178] (Second Embodiment) Next, a second embodiment, which differs from the embodiment described above, will be described with reference to Figure 13. In the vehicle air conditioning system 1 according to the second embodiment, the configuration of the second heat transfer medium circuit 20 differs from that of the first embodiment described above. The other components of the vehicle air conditioning system 1 according to the second embodiment (first heat transfer medium circuit 10, refrigeration cycle 30, indoor air conditioning unit 50, control device 60, etc.) are the same as those of the first embodiment described above, so a further explanation will be omitted.

[0179] As shown in Figure 13, the second heat transfer medium circuit 20 of the vehicle air conditioning system 1 according to the second embodiment includes a second heat transfer medium pump 22, a heat transfer medium heat exchanger 13, a heater core 23, and a heat transfer medium refrigerant heat exchanger 32 which is a component of the second heat source 21. In other words, the second heat transfer medium circuit 20 according to the second embodiment differs from the first embodiment in that it does not have a heat transfer medium bypass passage 24, a heat transfer medium three-way valve 25, a heat transfer medium confluence section 26, and a heat transfer medium radiator 27. Therefore, in the second heat transfer medium circuit 20 of the second embodiment, all of the second heat transfer medium that flows out from the heat transfer medium heat exchanger 13 flows into the heater core 23.

[0180] In the vehicle air conditioning system 1 according to the second embodiment, the same effects as those of the first embodiment described above can be achieved, except for matters relating to the heat quantity adjustment unit 45 and the heat dissipation unit 46 in the second heat transfer medium circuit 20.

[0181] In the second embodiment, the first heat transfer medium circuit 10 has a bypass flow path 15 and a four-way valve 16 as a heat quantity adjustment unit 45, and an outside air radiator 14 as a heat dissipation unit 46. Therefore, by using the heat quantity adjustment unit 45 and the heat dissipation unit 46 of the first heat transfer medium circuit 10, the amount of heat supplied to the heat transfer medium heat exchanger 13 can be adjusted, and the function of adjusting the heating performance of the vehicle air conditioning system 1 is also ensured.

[0182] As described above, according to the vehicle air conditioning system 1 of the second embodiment, even if the configuration of the second heat transfer medium circuit 20 is changed, the effects and advantages obtained from the configuration and operation common to the above-described embodiment can be obtained.

[0183] (Third embodiment) Next, a third embodiment, which differs from the embodiments described above, will be explained with reference to Figure 14. In the vehicle air conditioning system 1 according to the third embodiment, the configuration of the first heat transfer medium circuit 10 differs from that of the first embodiment described above. The other components of the vehicle air conditioning system 1 according to the third embodiment (second heat transfer medium circuit 20, refrigeration cycle 30, indoor air conditioning unit 50, control device 60, etc.) are the same as those of the first embodiment described above, so a further explanation will be omitted.

[0184] As shown in Figure 14, the first heat transfer medium circuit 10 of the vehicle air conditioning system 1 according to the third embodiment includes an engine 11a as a first heat source 11, a first heat transfer medium pump 12, a heat transfer medium heat exchanger 13, and an outside air radiator 14. In other words, the first heat transfer medium circuit 10 according to the third embodiment differs from the first embodiment in that it does not have a bypass flow path 15, a four-way valve 16, a branch section 17, or a merging section 18. Therefore, in the first heat transfer medium circuit 10 of the third embodiment, all of the first heat transfer medium that flows out from the first heat source 11 flows into the heat transfer medium heat exchanger 13.

[0185] In the vehicle air conditioning system 1 according to the third embodiment, the same effects as those of the first embodiment described above can be achieved, except for matters relating to the heat quantity adjustment unit 45 and the heat dissipation unit 46 in the first heat transfer medium circuit 10.

[0186] In the third embodiment, the second heat transfer medium circuit 20 has a heat transfer medium bypass channel 24 and a heat transfer medium three-way valve 25 as a heat quantity adjustment unit 45, and a heat transfer medium radiator 27 as a heat dissipation unit 46. Therefore, by using the heat quantity adjustment unit 45 and the heat dissipation unit 46 of the second heat transfer medium circuit 20, the amount of heat supplied to the heat transfer medium heat exchanger 13 can be adjusted, and the function of adjusting the heating performance of the vehicle air conditioning system 1 is also ensured.

[0187] As described above, according to the vehicle air conditioning system 1 of the third embodiment, even if the configuration of the first heat transfer medium circuit 10 is changed, the effects and advantages obtained from the configuration and operation common to the above-described embodiment can be obtained.

[0188] (Fourth Embodiment) Next, a fourth embodiment, which differs from the embodiments described above, will be described with reference to Figure 15. The vehicle air conditioning system 1 according to the fourth embodiment differs from the first embodiment in the configuration of the first heat transfer medium circuit 10, the second heat transfer medium circuit 20, and the refrigeration cycle 30. The other components of the vehicle air conditioning system 1 according to the fourth embodiment (indoor air conditioning unit 50, indoor air conditioning unit 50) are the same as those of the first embodiment described above, so a further explanation will be omitted.

[0189] As shown in Figure 15, the first heat transfer medium circuit 10 of the vehicle air conditioning system 1 according to the fourth embodiment includes an engine 11a as a first heat source 11, a first heat transfer medium pump 12, a heat transfer medium heat exchanger 13, and an outside air radiator 14. In other words, the first heat transfer medium circuit 10 according to the fourth embodiment does not have a configuration corresponding to a heat quantity adjustment unit 45 and a heat dissipation unit 46, and has the same configuration as the first heat transfer medium circuit 10 according to the third embodiment.

[0190] Furthermore, the second heat transfer medium circuit 20 of the vehicle air conditioning system 1 according to the fourth embodiment includes a second heat transfer medium pump 22, a heat transfer medium heat exchanger 13, a heater core 23, and a heat transfer medium refrigerant heat exchanger 32 which is a component of the second heat source 21. In other words, the second heat transfer medium circuit 20 according to the second embodiment does not have components corresponding to the heat quantity adjustment unit 45 and the heat dissipation unit 46, and has the same configuration as the second heat transfer medium circuit 20 according to the second embodiment.

[0191] In the vehicle air conditioning system 1 according to the fourth embodiment, a refrigeration cycle 30 is provided as the second heat source 21. The refrigeration cycle 30 according to the fourth embodiment has a compressor 31, a heat exchanger 32, a first expansion valve 34, a first evaporator 35, a second expansion valve 36, and a second evaporator 37, similar to the embodiments described above. The refrigeration cycle 30 according to the fourth embodiment further has components corresponding to a heat quantity adjustment unit 45 and a heat dissipation unit 46.

[0192] As shown in Figure 15, in the refrigeration cycle 30 according to the fourth embodiment, a refrigerant three-way valve 39 is positioned between the discharge port of the compressor 31 and the refrigerant inlet in the refrigerant passage 32b of the heat transfer medium refrigerant heat exchanger 32. The refrigerant three-way valve 39 is composed of an electric three-way flow control valve having three inlet and outlet ports, with one of the three inlet and outlet ports serving as the inlet and the other two as outlet ports. The refrigerant three-way valve 39 functions as a branching point with respect to the flow of refrigerant discharged from the compressor 31.

[0193] The inlet of the refrigerant three-way valve 39 is connected to the discharge port side of the compressor 31. One of the outlets of the refrigerant three-way valve 39 is connected to the refrigerant inlet side of the refrigerant passage 32b of the heat transfer medium refrigerant heat exchanger 32, and the other outlet of the refrigerant three-way valve 39 is connected to the refrigerant radiator 41 via the refrigerant bypass passage 38.

[0194] The refrigerant radiator 41 exchanges heat between the high-pressure refrigerant discharged from the compressor 31 and the outside air, releasing the heat contained in the high-pressure refrigerant into the outside air. A refrigerant connection section 40 with a three-way joint structure is connected to the refrigerant outlet side of the refrigerant radiator 41 via a refrigerant bypass flow path 38. The refrigerant connection section 40 uses one of the three inlet / outlet ports of the three-way joint structure as the outlet and the remaining two as the inlet ports.

[0195] As described above, one inlet of the refrigerant connection section 40 is connected to the outlet side of the refrigerant radiator 41 via the refrigerant bypass flow path 38, and the other inlet of the refrigerant connection section 40 is connected to the outlet side of the refrigerant passage 32b of the heat transfer medium refrigerant heat exchanger 32. The inlet side of the refrigerant branch section 33a is connected to the outlet of the refrigerant connection section 40.

[0196] In the refrigeration cycle 30 configured in this way according to the fourth embodiment, the operation of the refrigerant three-way valve 39 can be controlled to allow the high-pressure refrigerant discharged from the compressor 31 to flow through the refrigerant bypass passage 38, bypassing the heat transfer medium refrigerant heat exchanger 32. That is, in the refrigeration cycle 30 according to the fourth embodiment, the amount of heat originating from the high-pressure refrigerant flowing into the heat transfer medium refrigerant heat exchanger 32 can be adjusted, and the amount of heat released to the second heat transfer medium can be adjusted. As described above, in the heater core 23, the blown air is heated by the heat contained in the second heat transfer medium, so the vehicle air conditioning system 1 according to the fourth embodiment can adjust the heating performance.

[0197] In the refrigeration cycle 30 according to the fourth embodiment, the refrigerant bypass channel 38, the refrigerant three-way valve 39, and the refrigerant connection section 40 correspond to an example of the heat quantity adjustment section 45, and the refrigerant radiator 41 corresponds to an example of the heat dissipation section 46.

[0198] In the vehicle air conditioning system 1 according to the fourth embodiment, the same effects as those of the first embodiment described above can be achieved, except for matters relating to the heat quantity adjustment unit 45 and the heat dissipation unit 46 in the refrigeration cycle 30.

[0199] As described above, according to the vehicle air conditioning system 1 of the fourth embodiment, even if the configuration of the refrigeration cycle 30 as the second heat source 21 is changed, the effects and advantages obtained from the configuration and operation common to the above-described embodiment can be obtained.

[0200] (Fifth embodiment) Next, a fifth embodiment, which differs from the embodiments described above, will be explained with reference to Figure 16. In the vehicle air conditioning system 1 according to the fifth embodiment, the configuration used as the second heat source 21 differs from that of the embodiments described above. The other configurations of the vehicle air conditioning system 1 according to the fifth embodiment (first heat transfer medium circuit 10, second heat transfer medium circuit 20, indoor air conditioning unit 50, control device 60) are the same as those of the embodiments described above, so a further explanation will be omitted.

[0201] As shown in Figure 16, in the vehicle air conditioning system 1 according to the fifth embodiment, an electric heater 42 is arranged as the second heat source 21 in the second heat transfer medium circuit 20. In the fifth embodiment, the electric heater 42 is arranged between the outlet of the heater core 23 in the second heat transfer medium circuit 20 and the suction port side of the second heat transfer medium pump 22.

[0202] The electric heater 42 generates heat when power is supplied to it, and heats the second heat transfer medium flowing through the heat transfer medium passage of the electric heater 42. For example, a PTC heater having a PTC element (i.e., a positive characteristic thermistor) can be used as the electric heater 42. The amount of heat that the electric heater 42 provides to heat the second heat transfer medium can be arbitrarily adjusted by the control voltage output from the control device 60, and this corresponds to an example of a second heat source 21.

[0203] Therefore, according to the vehicle air conditioning system 1 of the fifth embodiment, even when an electric heater 42 is used instead of a refrigeration cycle 30 as the second heat source 21, the waste heat from the engine 11a and the heat generated by the electric heater 42 can be efficiently utilized to provide stable heating performance.

[0204] As described above, according to the vehicle air conditioning system 1 of the fifth embodiment, even when an electric heater 42 is used as the second heat source 21 instead of the refrigeration cycle 30, the effects and advantages obtained from the common configuration and operation of the above-described embodiment can be obtained. (Other embodiments) This disclosure is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit of this disclosure, as follows.

[0205] (a) In the above-described embodiment, an engine 11a that incidentally generates heat in conjunction with the combustion of fuel for the purpose of driving was used as the first heat source 11, but the embodiment is not limited to this. Various on-board equipment can be used as the first heat source 11, as long as it is an on-board equipment mounted on the vehicle that incidentally generates heat in conjunction with its operation for the purpose of driving.

[0206] For example, the first heat source 11 may be an on-board battery, an inverter INV, a motor generator MG, a transaxle device, a PCU, a control device for ADAS, etc. For example, a drive motor can be used as the first heat source 11 because it generates heat when energized to produce driving force. Also, an on-board battery can be used as the first heat source 11 because it generates heat as power is input and output during driving.

[0207] The inverter (INV) is a power conversion unit that converts direct current (DC) to alternating current (AC). The motor generator (MG) outputs driving force for propulsion when power is supplied to it, and also generates regenerative power during deceleration, etc.

[0208] The transaxle is a device that integrates the transmission with the final gear and differential gear. The PCU is a power control unit that performs power transformation and power distribution. The ADAS control device is a control device for advanced driver assistance systems. These components, like the engine 11a, generate heat incidentally as they operate for purposes such as driving the vehicle, and can therefore be used as the first heat source 11.

[0209] (b) In the embodiments described above, a refrigeration cycle 30 or an electric heater 42 was used as the second heat source 21, but the invention is not limited to this embodiment. Various configurations can be used as the second heat source 21, as long as the amount of heat used to heat the second heat medium can be adjusted by the control device 60. For example, a Peltier element may be used.

[0210] (c) The circuit configuration of the first heat transfer medium circuit 10, the second heat transfer medium circuit 20, and the refrigeration cycle 30 in the above-described embodiment is an example, and the configuration of the first heat transfer medium circuit 10, the second heat transfer medium circuit 20, and the refrigeration cycle 30 can be changed as appropriate.

[0211] Regarding the first heat transfer medium circuit 10, the connection configuration of each component can be changed as appropriate, as long as the configuration allows the first heat transfer medium to be circulated via the first heat source 11 and the heat transfer medium heat exchanger 13. Similarly, regarding the second heat transfer medium circuit 20, the connection configuration of each component can be changed as appropriate, as long as the configuration includes the heat transfer medium heat exchanger 13, the second heat source 21, and the heater core 23, and allows the second heat transfer medium to be circulated.

[0212] Furthermore, with respect to the refrigeration cycle 30, the components of the refrigeration cycle 30 and the way each component is connected may be appropriately changed, as long as the configuration allows the heat pumped up by the cycle to be dissipated to the second heat transfer medium. For example, in the embodiment described above, the first expansion valve 34 and the first evaporator 35 were connected in parallel with the second expansion valve 36 and the second evaporator 37, but the number of expansion valves and evaporators may be changed.

[0213] (d) In the above-described embodiment, the configuration corresponding to the heat dissipation section 46 was an outside air radiator 14, a heat transfer fluid radiator 27, and a refrigerant radiator 41, and heat from either the first heat transfer fluid, the second heat transfer fluid, or the refrigerant was dissipated to the outside air, but the embodiment is not limited to this. The heat dissipation section 46 only needs to be able to dissipate heat to the outside from a circulation circuit such as the first heat transfer fluid circuit 10, the second heat transfer fluid circuit 20, and the refrigerant connection section 40, and the object from which heat is dissipated is not particularly limited.

[0214] The features of the vehicle air conditioning system disclosed herein are as follows: (Item 1) A first heat transfer medium circuit (10) circulates a first heat transfer medium via a first heat source (11, 11a) that generates heat as the vehicle moves, A second heat transfer medium circuit (20) circulates a second heat transfer medium via a second heat source (21, 30, 42) whose amount of heat generated can be adjusted, and a heater core (23) that heats the blown air supplied to the air-conditioned space by heat exchange. A heat exchanger (13) that exchanges heat between the first heat transfer medium circulating in the first heat transfer medium circuit and the second heat transfer medium circulating in the second heat transfer medium circuit, A vehicle air conditioning system having a control unit (60) that controls the operation of the first heat transfer fluid circuit and the second heat transfer fluid circuit. (Item 2) The second heat source is, The vehicle air conditioning system according to item 1, comprising a refrigeration cycle (30) having a compressor (31) that compresses and discharges a refrigerant, a heat transfer medium refrigerant heat exchanger (32) that dissipates the heat of the high-pressure refrigerant compressed by the compressor to the second heat transfer medium, a pressure reducing unit (34, 36) that reduces the pressure of the refrigerant that has flowed out of the heat transfer medium refrigerant heat exchanger, and an evaporator (35, 37) that evaporates the refrigerant that has flowed out of the pressure reducing unit. (Item 3) A heat quantity adjustment unit (45) adjusts the amount of heat supplied to the heat exchanger, The vehicle air conditioning system according to item 1 or 2, further comprising a heat dissipation unit (46) that dissipates the amount of heat that was not fed into the heat exchanger by the heat quantity adjustment unit. (Item 4) The heat quantity adjustment unit (45) includes a bypass channel (15) that allows the first heat medium to flow in the first heat medium circuit so as to bypass the heat medium heat exchanger, and a flow rate adjustment unit (16) that adjusts the flow rate of the first heat medium flowing toward the bypass channel and the flow rate of the first heat medium flowing toward the heat medium heat exchanger. The vehicle air conditioning system according to item 3, wherein the heat dissipation section (46) is an external heat sink (14) arranged in the flow path of the first heat transfer medium circuit and dissipates the heat of the first heat transfer medium to the outside. (Item 5) The heat quantity adjustment unit (45) includes a heat medium bypass channel (24) that allows the second heat medium to flow in the second heat medium circuit so as to bypass the heat medium heat exchanger, and a heat medium flow rate adjustment unit (25) that adjusts the flow rate of the second heat medium flowing toward the heat medium bypass channel and the flow rate of the second heat medium flowing toward the heat medium heat exchanger. The vehicle air conditioning system according to item 3, wherein the heat dissipation section (46) is a heat transfer radiator (27) arranged in the heat transfer bypass channel of the second heat transfer circuit, which dissipates heat from the second heat transfer flowing through the heat transfer bypass channel to the outside. (Item 6) A heat quantity adjustment unit (45) adjusts the amount of heat supplied to the heat exchanger, The heat quantity adjustment unit has a heat dissipation unit (46) that dissipates the amount of heat that was not put into the heat exchanger of the heat medium, The heat quantity adjustment unit includes, in the refrigeration cycle, a refrigerant bypass channel (38) that directs the refrigerant discharged from the compressor to flow into the depressurization section, bypassing the heat transfer medium refrigerant heat exchanger, and a refrigerant flow rate adjustment unit (40) that adjusts the flow rate of the refrigerant flowing towards the refrigerant bypass channel and the flow rate of the refrigerant flowing towards the heat transfer medium refrigerant heat exchanger. The vehicle air conditioning system according to item 2, wherein the heat dissipation section is a refrigerant radiator (41) arranged in the refrigerant bypass flow path in the refrigeration cycle, which dissipates heat from the high-pressure refrigerant flowing through the refrigerant bypass flow path to the outside. (Item 7) The control unit, regarding the flow of the first heat transfer medium in the first heat transfer medium circuit, A first circulation mode in which the first heat transfer medium circulates via the external heat sink, the first heat source, and the heat transfer medium heat exchanger, The vehicle air conditioning system according to item 4, which switches to either a second circulation mode in which the first heat medium circulates via the external heat exchanger and the first heat source without passing through the heat medium heat exchanger. (Item 8) The control unit, regarding the flow of the first heat transfer medium in the first heat transfer medium circuit, The vehicle air conditioning system according to item 7, which switches to a third circulation mode in which a portion of the first heat transfer medium that has passed through the external heat radiator and the first heat source passes through the heat transfer medium heat exchanger, while the remaining portion circulates by bypassing the heat transfer medium heat exchanger. (Item 9) The control unit, regarding the flow of the first heat transfer medium in the first heat transfer medium circuit, The vehicle air conditioning system according to item 8, which switches to a fourth circulation mode in which the first heat transfer medium circulates via the heat transfer medium heat exchanger and the external heat radiator. (Item 10) The vehicle air conditioning system according to any one of items 1 to 9, wherein the second heat source (21, 30, 42) is located upstream of the heat exchanger (13) with respect to the flow of the second heat medium in the second heat medium circuit. (Item 11) The vehicle air conditioning system according to any one of items 1 to 10, wherein the heater core (23) is located upstream of the second heat source (21, 30, 42) with respect to the flow of the second heat medium in the second heat medium circuit. (Item 12) The vehicle air conditioning system according to item 5, wherein the heat transfer medium heat exchanger (13) is located upstream of the branching portion (25) to the heat transfer medium bypass flow path with respect to the flow of the second heat transfer medium in the second heat transfer medium circuit. (Item 13) The control unit (60) will, when switching from a state in which the second heat source is being used for heating to a state in which at least the first heat source is being used for heating, With the second heat source activated and the second heat transfer medium circulating in the second heat transfer medium circuit at least through the second heat source and the heater core, the first heat transfer medium circuit waits for the first heat transfer medium to flow to the heat transfer medium heat exchanger until the temperature of the first heat transfer medium satisfies predetermined conditions. A vehicle air conditioning system according to any one of items 1 to 12, wherein, when the temperature of the first heat transfer medium satisfies predetermined conditions, the second heat transfer medium is circulated in the second heat transfer medium circuit at least through the heater core and the heat transfer medium heat exchanger, and the first heat transfer medium is circulated in the first heat transfer medium circuit through the first heat source and the heat transfer medium heat exchanger. (Item 14) The control unit (60) performs heating using the second heat source when the first heat source is operating. With the first heat source operating and the first heat transfer medium circulating through the first heat transfer medium circuit via the first heat source and the heat transfer medium heat exchanger, the second heat transfer medium is circulated through the second heat source, the heater core and the heat transfer medium heat exchanger in the second heat transfer medium circuit. A vehicle air conditioning system according to any one of items 1 to 13, wherein, when the temperature of the second heat medium satisfies predetermined conditions, the circulation of the first heat medium through the heat medium heat exchanger in the first heat medium circuit is stopped, and the circulation of the second heat medium through at least the second heat source and the heater core is performed in the second heat medium circuit. [Explanation of Symbols]

[0215] 1. Vehicle air conditioning system 10 1st heat carrier circuit 11 1st heat source 11a engine 13 Heat medium heat exchanger 20 Second heat carrier circuit 21 Second heat source 23 Heater core 60 Control device

Claims

1. A first heat transfer medium circuit (10) circulates a first heat transfer medium via a first heat source (11, 11a) that generates heat as the vehicle moves, A second heat transfer medium circuit (20) circulates a second heat transfer medium via a second heat source (21, 30, 42) whose amount of heat generated can be adjusted, and a heater core (23) that heats the blown air supplied to the air-conditioned space by heat exchange. A heat exchanger (13) that exchanges heat between the first heat transfer medium circulating in the first heat transfer medium circuit and the second heat transfer medium circulating in the second heat transfer medium circuit, A control unit (60) that controls the operation of the first heat transfer fluid circuit and the second heat transfer fluid circuit, A heat quantity adjustment unit (45) adjusts the amount of heat supplied to the heat exchanger, The heat quantity adjustment unit has a heat dissipation unit (46) that dissipates the amount of heat that was not put into the heat exchanger, The heat quantity adjustment unit (45) includes a bypass channel (15) that allows the first heat medium to flow in the first heat medium circuit so as to bypass the heat medium heat exchanger, and a flow rate adjustment unit (16) that adjusts the flow rate of the first heat medium flowing toward the bypass channel and the flow rate of the first heat medium flowing toward the heat medium heat exchanger. The heat dissipation unit (46) is an external heat sink (14) arranged in the flow path of the first heat transfer medium circuit, which dissipates the heat of the first heat transfer medium to the outside, in this vehicle air conditioning system.

2. The second heat source is, The vehicle air conditioning system according to claim 1, comprising a refrigeration cycle (30) having a compressor (31) that compresses and discharges a refrigerant, a heat transfer medium refrigerant heat exchanger (32) that dissipates the heat of the high-pressure refrigerant compressed by the compressor to the second heat transfer medium, a pressure reducing unit (34, 36) that reduces the pressure of the refrigerant that has flowed out of the heat transfer medium refrigerant heat exchanger, and an evaporator (35, 37) that evaporates the refrigerant that has flowed out of the pressure reducing unit.

3. The heat quantity adjustment unit (45) includes a heat medium bypass channel (24) that allows the second heat medium to flow in the second heat medium circuit so as to bypass the heat medium heat exchanger, and a heat medium flow rate adjustment unit (25) that adjusts the flow rate of the second heat medium flowing toward the heat medium bypass channel and the flow rate of the second heat medium flowing toward the heat medium heat exchanger. The vehicle air conditioning system according to claim 1, wherein the heat dissipation section (46) is a heat transfer radiator (27) arranged in the heat transfer bypass channel of the second heat transfer circuit, which dissipates heat from the second heat transfer flowing through the heat transfer bypass channel to the outside.

4. A heat quantity adjustment unit (45) adjusts the amount of heat supplied to the heat exchanger, The heat quantity adjustment unit has a heat dissipation unit (46) that dissipates the amount of heat that was not put into the heat exchanger, The heat quantity adjustment unit includes, in the refrigeration cycle, a refrigerant bypass channel (38) that directs the refrigerant discharged from the compressor to flow into the depressurization section, bypassing the heat transfer medium refrigerant heat exchanger, and a refrigerant flow rate adjustment unit (40) that adjusts the flow rate of the refrigerant flowing towards the refrigerant bypass channel and the flow rate of the refrigerant flowing towards the heat transfer medium refrigerant heat exchanger. The vehicle air conditioning system according to claim 2, wherein the heat dissipation unit is a refrigerant radiator (41) arranged in the refrigerant bypass flow path in the refrigeration cycle, which dissipates heat from the high-pressure refrigerant flowing through the refrigerant bypass flow path to the outside.

5. The control unit has a view to the flow of the first heat transfer medium in the first heat transfer medium circuit. A first circulation mode in which the first heat transfer medium circulates via the external heat sink, the first heat source, and the heat transfer medium heat exchanger, The vehicle air conditioning system according to claim 1, which switches to either a second circulation mode in which the first heat medium circulates via the external heat radiator and the first heat source without going through the heat medium heat exchanger.

6. The control unit has a view to the flow of the first heat transfer medium in the first heat transfer medium circuit. The vehicle air conditioning system according to claim 5, wherein a portion of the first heat transfer medium that has passed through the external heat radiator and the first heat source passes through the heat transfer medium heat exchanger, while the remaining portion of the heat transfer medium circulates around the heat transfer medium heat exchanger.

7. The control unit has a view to the flow of the first heat transfer medium in the first heat transfer medium circuit. The vehicle air conditioning system according to claim 6, which switches to a fourth circulation mode in which the first heat transfer medium circulates via the heat transfer medium heat exchanger and the external heat radiator.

8. The vehicle air conditioning system according to claim 1, wherein the second heat source (21, 30, 42) is arranged upstream of the heat exchanger (13) with respect to the flow of the second heat medium in the second heat medium circuit.

9. The vehicle air conditioning system according to claim 1, wherein the heater core (23) is arranged upstream of the second heat source (21, 30, 42) with respect to the flow of the second heat medium in the second heat medium circuit.

10. The vehicle air conditioning system according to claim 3, wherein the heat transfer medium heat exchanger (13) is positioned upstream of the branching portion (25) to the heat transfer medium bypass flow path with respect to the flow of the second heat transfer medium in the second heat transfer medium circuit.

11. The control unit (60) will, when switching from a state in which the second heat source is being used for heating to a state in which at least the first heat source is being used for heating, With the second heat source activated and the second heat transfer medium circulating in the second heat transfer medium circuit at least through the second heat source and the heater core, the first heat transfer medium circuit waits for the first heat transfer medium to flow to the heat transfer medium heat exchanger until the temperature of the first heat transfer medium satisfies predetermined conditions. The vehicle air conditioning system according to claim 1, wherein, when the temperature of the first heat transfer medium satisfies predetermined conditions, the second heat transfer medium is circulated in the second heat transfer medium circuit via at least the heater core and the heat transfer medium heat exchanger, and the first heat transfer medium is circulated in the first heat transfer medium circuit via the first heat source and the heat transfer medium heat exchanger.

12. The control unit (60) will, when performing heating using the second heat source from a state in which the first heat source is operating, While the first heat source is operating and the first heat transfer medium is circulating in the first heat transfer medium circuit via the first heat source and the heat transfer medium heat exchanger, the second heat transfer medium is circulated in the second heat transfer medium circuit via the second heat source, the heater core and the heat transfer medium heat exchanger. The vehicle air conditioning system according to claim 1, wherein when the temperature of the second heat medium satisfies predetermined conditions, the circulation of the first heat medium through the heat medium heat exchanger in the first heat medium circuit is stopped, and the circulation of the second heat medium through at least the second heat source and the heater core is performed in the second heat medium circuit.

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