Vehicle air conditioning system

Abstract

This vehicle air conditioning system is provided with: a refrigerant flow path for circulating a refrigerant between a condenser and an evaporator; a cooling liquid flow path for circulating a cooling liquid that exchanges heat with the refrigerant in the condenser and the evaporator; and a first heat exchanger that exchanges heat between air and the cooling liquid to cool / heat a vehicle interior. The flow state of the cooling liquid in the cooling liquid flow path is switched between a first state in which the cooling liquid from one of the condenser and the evaporator flows through the first heat exchanger, and a second state in which the cooling liquid from both the condenser and the evaporator flows through the first heat exchanger.

Description

Vehicle air conditioning system

[0001] The present disclosure relates to a vehicle air conditioning system that cools and heats a vehicle interior.

[0002] 2. Description of the Related Art Conventionally, vehicle air conditioning systems have been used to cool and heat the interior of a vehicle. A technology relating to such a vehicle air conditioning system is disclosed in, for example, Patent Document 1, the source of which is shown below.

[0003] Patent Document 1 describes a vehicle air conditioner that includes a cooler core that exchanges heat between air and coolant and a heater core that exchanges heat between the air and coolant after heat exchange in the cooler core, both of which are housed within a casing that defines an air passage through which air flows toward the vehicle interior.

[0004] JP 2015-16706 A

[0005] In the vehicle air conditioning device (corresponding to a "vehicle air conditioning system") described in Patent Document 1, coolant is circulated through the heater core even when cooling the vehicle interior. This makes it difficult to regulate the temperature when the outside air temperature is high. For this reason, the vehicle air conditioning device described in Patent Document 1 has room for improvement in terms of temperature regulation.

[0006] Therefore, there is a demand for a vehicle air conditioning system that can regulate the temperature even when the outside air temperature is high.

[0007] The characteristic configuration of the vehicle air conditioning system of the present disclosure is that it comprises a refrigerant flow path that circulates refrigerant through a condenser and an evaporator, a coolant flow path that circulates coolant that exchanges heat with the refrigerant in the condenser and the evaporator, and a first heat exchanger that exchanges heat between air and the coolant to cool or heat the vehicle interior, and the state in which the coolant flows through the coolant flow path can be switched between a first state in which the coolant from one of the condenser and the evaporator flows through the first heat exchanger, and a second state in which the coolant from both the condenser and the evaporator flows through the first heat exchanger.

[0008] With this characteristic configuration, when the situation allows for adjustment of the temperature of the coolant, the coolant from either the condenser or the evaporator is circulated through the coolant flow path, and the temperature of the coolant is adjusted as needed; when the situation makes it difficult to adjust the temperature of the coolant, the coolant from both the condenser and the evaporator is mixed to adjust the temperature of the coolant.

[0009] It is a circuit configuration diagram of a vehicle air conditioning system. It is a diagram showing the relationship between a first state, a second state, and the state of a radiator. It is a diagram showing the flow of coolant in heating operation or dehumidifying heating operation. It is a diagram showing the flow of coolant in dehumidifying heating operation. It is a diagram showing the flow of coolant in cooling operation. It is a diagram showing the flow of coolant in cooling reheat operation. It is a diagram showing changes in blown-out temperature.

[0010] The vehicle air conditioning system according to the present disclosure is configured to be able to cool and heat the vehicle cabin. The vehicle air conditioning system 1 according to the present embodiment will be described below. However, the vehicle air conditioning system 1 is not limited to the following embodiment, and various modifications are possible within the scope of the gist thereof.

[0011] FIG. 1 is a diagram showing the circuit configuration of a vehicle air conditioning system 1. The vehicle air conditioning system 1 is mounted on a vehicle and, as shown in FIG. 1, includes a refrigerant module 2, a coolant module 3, and an HVAC unit 4 (heating, ventilation, and air conditioning unit). The refrigerant module 2 is provided with a refrigerant flow path 2A, which constitutes a refrigerant manifold. The coolant module 3 is provided with a coolant flow path 3A, which constitutes a coolant manifold. Here, the manifold is a flow path housing formed by laminating and sealing a plate member on a housing main body in which the coolant flow paths 3A and 2A are engraved. The flow path housing is formed of a metal material with high thermal conductivity, including aluminum.

[0012] A refrigerant such as a hydrofluorocarbon (HFC) or a hydrofluoroolefin (HFO) flows through the refrigerant flow path 2A, while a coolant flow path 3A carries a coolant such as an antifreeze solution or long-life coolant containing ethylene glycol as a main component, or a paraffin-based insulating oil.

[0013] The refrigerant flow path 2A circulates the refrigerant between the water-cooled condenser (an example of a "condenser") 12 and the chiller (an example of an "evaporator") 14. The refrigerant module 2 is configured to allow the refrigerant to flow between the accumulator 10, the compressor 11, the water-cooled condenser 12, the expansion valve 13, and the chiller 14 via the refrigerant flow path 2A.

[0014] The accumulator 10 stores a liquid refrigerant and separates the stored refrigerant into gas and liquid. The gaseous refrigerant separated by the accumulator 10 flows through a first refrigerant flow path 21 and is sent to the compressor 11.

[0015] The compressor 11 compresses the refrigerant from the accumulator 10. As a result, the refrigerant becomes a high-temperature compressed gas. The compressor 11 sends this high-temperature compressed gas to the water-cooled condenser 12 via the second refrigerant flow path 22. Therefore, the compressor 11 pressure-feeds the refrigerant from the accumulator 10 to the water-cooled condenser 12.

[0016] The refrigerant that has passed through the compressor 11 flows through the water-cooled condenser 12. The water-cooled condenser 12 is configured so that the coolant flows in through a first coolant flow path 31 and flows out through a second coolant flow path 32. The first coolant flow path 31 and the second coolant flow path 32 are configured separately from the second refrigerant flow path 22. The refrigerant from the second refrigerant flow path 22 is condensed and liquefied as heat is absorbed by the coolant. The liquefied refrigerant is sent to the third refrigerant flow path 23. Like the second refrigerant flow path 22, the third refrigerant flow path 23 is also configured separately from the first coolant flow path 31 and the second coolant flow path 32.

[0017] In the expansion valve 13, the refrigerant (liquefied refrigerant) flowing through the third refrigerant flow path 23 is expanded and converted into a low-temperature, low-pressure mist. The mist-like refrigerant is sent to the fourth refrigerant flow path 24.

[0018] The refrigerant flows through the chiller 14 via the fourth refrigerant flow path 24. As described above, the refrigerant expanded by the expansion valve 13 and converted into a low-temperature, low-pressure atomized refrigerant flows through the fourth refrigerant flow path 24, and this refrigerant is sent to the chiller 14. The chiller 14 is configured such that the coolant that has undergone heat exchange in the cooler core 62 (an example of a "second heat exchanger") or the cooler core 62 and heater core 63 (an example of a "first heat exchanger") flows into the chiller 14 from the third coolant flow path 33, and the coolant flows out of the fourth coolant flow path 34. The third coolant flow path 33 and the fourth coolant flow path 34 are configured separately from the fourth refrigerant flow path 24. In the chiller 14, the atomized refrigerant absorbs heat from the coolant and evaporates. The evaporated refrigerant flows through the fifth refrigerant flow path 25 to the accumulator 10.

[0019] The coolant flow path 3A also carries the coolant that exchanges heat with the refrigerant in the water-cooled condenser 12 and the chiller 14. The coolant module 3 is configured such that the coolant can flow through the coolant flow path 3A among the water-cooled condenser 12, the chiller 14, the first switching valve 51, the second switching valve 52, the third switching valve 53, the radiator 54, the cooler core 62, and the heater core 63 by the first pump P1 and the second pump P2. A check valve 55 is also provided in the coolant flow path 3A.

[0020] As described above, the water-cooled condenser 12 is configured so that the coolant flows in through the first coolant flow path 31 and flows out through the second coolant flow path 32. The first coolant flow path 31 is provided with a first pump P1, and the coolant is delivered by this first pump P1.

[0021] The first switching valve 51 is disposed in the coolant flow path 3A, and is configured to allow the coolant to flow from the water-cooled condenser 12 and the chiller 14. The coolant is sent from the water-cooled condenser 12 to the first switching valve 51 via the second coolant flow path 32, and from the chiller 14 via the fourth coolant flow path 34, the third switching valve 53, and the fifth coolant flow path 35.

[0022] The first switching valve 51 is configured to be able to send the coolant to the sixth coolant flow path 36 and the seventh coolant flow path 37. The coolant sent from the first switching valve 51 to the sixth coolant flow path 36 flows to the heater core 63. The coolant sent to the heater core 63 is sent to the second switching valve 52 via the eighth coolant flow path 38.

[0023] The second switching valve 52 is configured to be able to send the coolant to the ninth coolant flow path 39 and the tenth coolant flow path 40. The coolant sent to the ninth coolant flow path 39 flows through the first coolant flow path 31 via the check valve 55.

[0024] The coolant sent from the first switching valve 51 to the seventh coolant flow path 37 flows to the radiator 54. In the radiator 54, heat is exchanged between the coolant and the outside air, and the coolant is cooled. After the heat exchange, the coolant is sent to the first coolant flow path 31 via the eleventh coolant flow path 41.

[0025] The coolant sent from the second switching valve 52 to the tenth coolant flow path 40 flows through the third coolant flow path 33 by the second pump P2 and is sent to the chiller 14. The coolant sent from the chiller 14 to the fourth coolant flow path 34 and to the third switching valve 53 is sent to the fifth coolant flow path 35 or the twelfth coolant flow path 42 described above.

[0026] The coolant sent to the twelfth coolant flow path 42 flows through the cooler core 62. The coolant sent to the cooler core 62 is sucked into the second pump P2 via the thirteenth coolant flow path 43 and flows through the third coolant flow path 33 to the chiller 14.

[0027] The flow state of the coolant in the coolant flow path 3A can be switched between a first state and a second state. In this embodiment, the first state and the second state are switched by a first switching valve 51, a second switching valve 52, and a third switching valve 53, as will be described later.

[0028] The first state is a state in which coolant from one of the water-cooled condenser 12 and the chiller 14 flows through the heater core 63. The state in which coolant from one of the water-cooled condenser 12 and the chiller 14 flows through the heater core 63 refers to a state in which coolant from the water-cooled condenser 12 flows through the heater core 63 but coolant from the chiller 14 does not flow, and a state in which coolant from the chiller 14 flows through the heater core 63 but coolant from the water-cooled condenser 12 does not flow. Therefore, in the first state, the first switching valve 51 includes a state in which the coolant from the second coolant flow path 32 is allowed to flow through the sixth coolant flow path 36 while blocking communication with the fifth coolant flow path 35 (hereinafter referred to as "state A"), a state in which the coolant from the second coolant flow path 32 is allowed to flow through the sixth coolant flow path 36 and the seventh coolant flow path 37 while blocking communication with the fifth coolant flow path 35 (hereinafter referred to as "state B"), and a state in which the coolant from the second coolant flow path 32 is allowed to flow only through the seventh coolant flow path 37 while the coolant from the fifth coolant flow path 35 is allowed to flow only through the sixth coolant flow path 36 (hereinafter referred to as "state C").

[0029] In the above-described states A and B, the coolant circulating between the water-cooled condenser 12 and the heater core 63 does not flow to the chiller 14 and the cooler core 62, and the coolant circulating between the chiller 14 and the cooler core 62 does not flow to the water-cooled condenser 12 and the heater core 63. Therefore, in states A and B, the second switching valve 52 is in a state where the coolant from the eighth coolant flow path 38 flows to the ninth coolant flow path 39 while blocking communication with the tenth coolant flow path 40, and the third switching valve 53 is in a state where the coolant from the fourth coolant flow path 34 flows to the twelfth coolant flow path 42 while blocking communication with the fifth coolant flow path 35.

[0030] In state C, the coolant circulating between the water-cooled condenser 12 and the radiator 54 does not flow to the chiller 14 and the cooler core 62, and the coolant circulating between the chiller 14 and the cooler core 62 does not flow to the water-cooled condenser 12 and the radiator 54. Therefore, in state C, the second switching valve 52 is in a state where the coolant from the eighth coolant flow path 38 flows to the tenth coolant flow path 40 while blocking communication with the ninth coolant flow path 39, and the third switching valve 53 is in a state where the coolant from the fourth coolant flow path 34 flows to the fifth coolant flow path 35 and the twelfth coolant flow path 42.

[0031] The second state is a state in which coolant from both the water-cooled condenser 12 and the chiller 14 flows through the heater core 63. The state in which coolant from both the water-cooled condenser 12 and the chiller 14 flows through the heater core 63 means that not only the coolant from the water-cooled condenser 12 flows through the heater core 63, but also the coolant from the chiller 14 flows through the heater core 63. Therefore, in the second state, the first switching valve 51 is set to a state in which a portion of the coolant from the second coolant flow path 32 and all of the coolant from the fifth coolant flow path 35 flow through the sixth coolant flow path 36. That is, in the second state, a mixture of the coolant with a relatively high temperature from the water-cooled condenser 12 and the coolant with a relatively low temperature from the chiller 14 flows through the heater core 63.

[0032] In the second state, the coolant that has flowed through the heater core 63 flows to the water-cooled condenser 12 and the chiller 14, and the coolant from the chiller 14 flows to the cooler core 62 and the heater core 63. Therefore, in the second state, the second switching valve 52 is in a state where the coolant from the eighth coolant flow path 38 flows to the ninth coolant flow path 39 and the tenth coolant flow path 40, and the third switching valve 53 is in a state where the coolant from the fourth coolant flow path 34 flows to the fifth coolant flow path 35 and the twelfth coolant flow path 42.

[0033] The switching between the first state and the second state is performed based on the state of the radiator 54. The state of the radiator 54 means a state in which the temperature of the coolant flowing through the heater core 63 can be adjusted by the radiator 54.

[0034] The state of the radiator 54 can be determined by at least one of the outside air temperature, the set temperature of the air conditioner, the temperature of the coolant, the flow rate of the coolant, and the amount of outside air introduced into the radiator 54. The outside air temperature is the temperature of the air outside the vehicle. The set temperature of the air conditioner is the temperature of the environment (air) in the passenger compartment 5 controlled by the HVAC unit 4. The coolant temperature is the temperature of the coolant flowing through the radiator 54. The flow rate of the coolant is the flow rate of the coolant flowing through the radiator 54. The amount of outside air introduced into the radiator 54 is the amount of outside air used for heat exchange in the radiator 54.

[0035] For example, when the temperature of the coolant is sufficiently high relative to the temperature of the outside air, it is possible to reduce the temperature of the coolant by the outside air in the radiator 54. On the other hand, when the temperature of the coolant is close to the temperature of the outside air, it is not easy to reduce the temperature of the coolant in the radiator 54.

[0036] Furthermore, for example, when the HVAC unit 4 cools the passenger compartment 5, if the coolant temperature is sufficiently high relative to the set temperature of the air conditioner, the radiator 54 cannot bring the coolant temperature close to the set temperature of the air conditioner. Also, for example, if the flow rate of the coolant is sufficiently low relative to the amount capable of cooling the coolant, the radiator 54 cannot lower the coolant temperature. Furthermore, if the amount of outside air introduced into the radiator 54 is sufficiently low relative to the amount capable of cooling the coolant, the radiator 54 cannot lower the coolant temperature.

[0037] In such a case, the radiator 54 is in a state where it is not possible to adjust the temperature of the coolant, so the state in which the coolant flows through the coolant flow path 3A is switched from the first state to the second state.

[0038] Specifically, when it is sufficient that the temperature of the coolant flowing through the heater core 63 is approximately the same as the temperature of the coolant from the water-cooled condenser 12, it is preferable to circulate the coolant from the water-cooled condenser 12 only through the heater core 63, as in the above-described state A. Furthermore, when it is necessary to lower the temperature of the coolant flowing through the heater core 63 below the temperature of the coolant from the water-cooled condenser 12, and the temperature difference is within a range that can be lowered by the radiator 54, it is preferable to circulate the coolant from the water-cooled condenser 12 through both the heater core 63 and the radiator 54, as in the above-described state B. Furthermore, when it is sufficient that the temperature of the coolant flowing through the heater core 63 is approximately the same as the temperature of the coolant from the chiller 14, it is preferable to circulate the coolant from the water-cooled condenser 12 through the radiator 54, and the coolant from the chiller 14 through the heater core 63, as in the above-described state C.

[0039] On the other hand, if it is desirable that the temperature of the coolant flowing through the heater core 63 be lower than the temperature of the coolant in state B and higher than the temperature of the coolant from the chiller 14, as in the second state described above, the coolant from the water-cooled condenser 12 and the coolant from the chiller 14 can be mixed and flowed through the heater core 63, while the coolant from the water-cooled condenser 12 can be flowed through the radiator 54.

[0040] The HVAC unit 4 includes a blower 61, a cooler core 62, and a heater core 63. The blower 61 draws in outside air and sends the drawn outside air to the cooler core 62.

[0041] The cooler core 62 exchanges heat between the air and the coolant from the chiller 14 to cool or heat the passenger compartment 5. The air is outside air drawn in by the blower 61. As described above, the coolant is introduced into the cooler core 62 via the twelfth coolant flow path 42, and this coolant is sent to the chiller 14 by the second pump P2. The cooler core 62 also has the function of condensing and removing moisture from moisture-containing air, converting it into dry air. Therefore, the cooler core 62 functions as an adsorption unit that adsorbs moisture. The cooler core 62 is provided between the blower 61 and the heater core 63. Therefore, the outside air sent from the blower 61 is sent to the heater core 63 via the cooler core 62.

[0042] The heater core 63 exchanges heat between air and coolant to cool or heat the vehicle compartment 5. The air is air sent from the cooler core 62. As described above, coolant is introduced into the heater core 63 via the sixth coolant flow path 36, and this coolant is sent to the second switching valve 52 via the eighth coolant flow path 38. Therefore, in the heater core 63, heat exchange occurs between the air sent from the cooler core 62 and the coolant supplied via the sixth coolant flow path 36, and the air after heat exchange is introduced into the vehicle compartment 5. Specifically, when the air is cooled in the heater core 63, cool air is introduced into the vehicle compartment 5, and when the air is heated in the heater core 63, warm air is introduced into the vehicle compartment 5. This makes it possible to cool or heat the vehicle compartment 5.

[0043] 2 shows the relationship between the flow state of the coolant in the coolant flow path 3A and the operating state of the HVAC unit 4. The first state includes state A, state B, and state C.

[0044] The flow state of the coolant in State A is shown in Figure 3. As described above, the refrigerant flows (circulates) through the accumulator 10, the first refrigerant flow path 21, the compressor 11, the second refrigerant flow path 22, the water-cooled condenser 12, the third refrigerant flow path 23, the expansion valve 13, the fourth refrigerant flow path 24, the chiller 14, and the fifth refrigerant flow path 25. In Figure 3, the flow state of the refrigerant is indicated by solid arrows.

[0045] In state A, the first switching valve 51 is in a state where the coolant from the second coolant flow path 32 flows through the sixth coolant flow path 36 while blocking communication with the fifth coolant flow path 35. The second switching valve 52 is in a state where the coolant from the eighth coolant flow path 38 flows through the ninth coolant flow path 39 while blocking communication with the tenth coolant flow path 40. Furthermore, the third switching valve 53 is in a state where the coolant from the fourth coolant flow path 34 flows through the twelfth coolant flow path 42 while blocking communication with the fifth coolant flow path 35.

[0046] As a result, the coolant flows through the first coolant flow path 31, the water-cooled condenser 12, the second coolant flow path 32, the first switching valve 51, the sixth coolant flow path 36, the heater core 63, the eighth coolant flow path 38, the second switching valve 52, the ninth coolant flow path 39, and the check valve 55 by the first pump P1, and flows through the third coolant flow path 33, the chiller 14, the fourth coolant flow path 34, the third switching valve 53, the twelfth coolant flow path 42, the cooler core 62, and the thirteenth coolant flow path 43 by the second pump P2. In Fig. 3, the flow state of the coolant flowed by the first pump P1 is indicated by dashed arrows, and the flow state of the coolant flowed by the second pump P2 is indicated by dashed arrows.

[0047] Therefore, the heat of the coolant discharged from the water-cooled condenser 12 is used for heat exchange with the air in the heater core 63, and the heat of the coolant discharged from the chiller 14 is used for heat exchange with the air in the cooler core 62. In this state A, the HVAC unit 4 is in a state where it performs heating operation or dehumidifying heating operation depending on the set temperature of the heating and cooling.

[0048] The flow state of the coolant in state B is shown in Figure 4. As in state A, the refrigerant flows (circulates) through the accumulator 10, first refrigerant flow path 21, compressor 11, second refrigerant flow path 22, water-cooled condenser 12, third refrigerant flow path 23, expansion valve 13, fourth refrigerant flow path 24, chiller 14, and fifth refrigerant flow path 25. In Figure 4, the flow state of the refrigerant is indicated by solid arrows.

[0049] In state B, the first switching valve 51 is in a state where the coolant from the second coolant flow path 32 is allowed to flow through the sixth coolant flow path 36 and the seventh coolant flow path 37 while blocking communication with the fifth coolant flow path 35. The second switching valve 52 is in a state where the coolant from the eighth coolant flow path 38 is allowed to flow through the ninth coolant flow path 39 while blocking communication with the tenth coolant flow path 40. Furthermore, the third switching valve 53 is in a state where the coolant from the fourth coolant flow path 34 is allowed to flow through the twelfth coolant flow path 42 while blocking communication with the fifth coolant flow path 35.

[0050] As a result, the coolant is circulated by the first pump P1 through the first coolant flow path 31, the water-cooled condenser 12, the second coolant flow path 32, the first switching valve 51, the sixth coolant flow path 36, the heater core 63, the eighth coolant flow path 38, the second switching valve 52, the ninth coolant flow path 39, and the check valve 55, and is also diverted from the first switching valve 51 and passes through the seventh coolant flow path 37, the radiator 54, and the eleventh coolant flow path 41 before joining the ninth coolant flow path 39. The coolant is circulated by the second pump P2 through the third coolant flow path 33, the chiller 14, the fourth coolant flow path 34, the third switching valve 53, the twelfth coolant flow path 42, the cooler core 62, and the thirteenth coolant flow path 43. In FIG. 4, the flow of the coolant by the first pump P1 is indicated by the dashed arrows, and the flow of the coolant by the second pump P2 is indicated by the broken arrows.

[0051] Therefore, the heat of the coolant sent from the water-cooled condenser 12 is used for heat exchange with the air in the heater core 63, and is also dissipated in the radiator 54. Also, the heat of the coolant from the chiller 14 is used for heat exchange with the air in the cooler core 62. In this state B, the HVAC unit 4 is in a state where it performs dehumidifying heating operation according to the set temperature of the heating and cooling.

[0052] The flow state of the coolant in state C is shown in Figure 5. As in state A, the refrigerant flows (circulates) through the accumulator 10, first refrigerant flow path 21, compressor 11, second refrigerant flow path 22, water-cooled condenser 12, third refrigerant flow path 23, expansion valve 13, fourth refrigerant flow path 24, chiller 14, and fifth refrigerant flow path 25. In Figure 5, the flow state of the refrigerant is indicated by solid arrows.

[0053] In state C, the first switching valve 51 allows the coolant from the second coolant flow path 32 to flow only through the seventh coolant flow path 37, and allows the coolant from the fifth coolant flow path 35 to flow only through the sixth coolant flow path 36. The second switching valve 52 allows the coolant from the eighth coolant flow path 38 to flow through the tenth coolant flow path 40, while blocking communication with the ninth coolant flow path 39. Furthermore, the third switching valve 53 allows the coolant from the fourth coolant flow path 34 to flow through the fifth coolant flow path 35 and the twelfth coolant flow path 42.

[0054] As a result, the first pump P1 causes the coolant to flow through the first coolant flow path 31, the water-cooled condenser 12, the second coolant flow path 32, the first switching valve 51, the seventh coolant flow path 37, the radiator 54, the eleventh coolant flow path 41, and the ninth coolant flow path 39. The second pump P2 also causes the coolant to flow through the third coolant flow path 33, the chiller 14, the fourth coolant flow path 34, the third switching valve 53, the twelfth coolant flow path 42, the cooler core 62, and the thirteenth coolant flow path 43, and also branches off from the third switching valve 53, and returns to the second pump P2 through the fifth coolant flow path 35, the first switching valve 51, the sixth coolant flow path 36, the heater core 63, the eighth coolant flow path 38, the second switching valve 52, and the tenth coolant flow path 40. In FIG. 5, the flow of the coolant by the first pump P1 is indicated by the dashed arrows, and the flow of the coolant by the second pump P2 is indicated by the broken arrows.

[0055] Therefore, the heat of the coolant discharged from the water-cooled condenser 12 is dissipated in the radiator 54, and the heat of the coolant discharged from the chiller 14 is used for heat exchange with the air in the cooler core 62 and the heater core 63. In this state C, the HVAC unit 4 is in a state where it performs cooling operation according to the set temperature of the heating and cooling.

[0056] The flow state of the coolant in the second state is shown in Figure 6. As in State A, the refrigerant flows (circulates) through the accumulator 10, the first refrigerant flow path 21, the compressor 11, the second refrigerant flow path 22, the water-cooled condenser 12, the third refrigerant flow path 23, the expansion valve 13, the fourth refrigerant flow path 24, the chiller 14, and the fifth refrigerant flow path 25. In Figure 6, the flow state of the refrigerant is indicated by solid arrows.

[0057] In the second state, the first switching valve 51 allows the coolant from the fifth coolant flow path 35 to flow through the sixth coolant flow path 36, and allows the coolant from the second coolant flow path 32 to flow through the sixth coolant flow path 36 and the seventh coolant flow path 37. Therefore, the sixth coolant flow path 36 is a mixture of the coolant from the second coolant flow path 32, which has a relatively high temperature, and the coolant from the fifth coolant flow path 35, which has a relatively low temperature.

[0058] The second switching valve 52 is also set to a state in which the coolant from the eighth coolant flow path 38 flows through the ninth coolant flow path 39 and the tenth coolant flow path 40. At this time, the coolant that has flowed through the heater core 63 is configured so that an amount of the coolant equal to the amount of the coolant that has flowed from the chiller 14 to the heater core 63 merges with the coolant that has flowed through the cooler core 62. That is, in the second state, the amount of the coolant flowing through the fifth coolant flow path 35 and the amount of the coolant flowing through the tenth coolant flow path 40 are configured to be equal to each other.

[0059] To make the amount of coolant flowing through the fifth coolant flow path 35 and the amount of coolant flowing through the tenth coolant flow path 40 equal to each other, it is preferable to do the following, for example: The amount of coolant flowing through the heater core 63 via the sixth coolant flow path 36 is calculated by subtracting the amount of coolant flowing through the radiator 54 (the amount of coolant flowing through the seventh coolant flow path 37) from the amount of coolant flowing from the water-cooled condenser 12 to the first selector valve 51 (the amount of coolant flowing through the second coolant flow path 32) and the amount of coolant flowing from the chiller 14 to the first selector valve 51 (the amount of coolant flowing through the fifth coolant flow path 35). As a result, of the coolant flowing to the heater core 63 via the sixth coolant flow path 36, the same amount of coolant as the amount of coolant flowing through the fifth coolant flow path 35 returns downstream of the cooler core 62 (flows through the tenth coolant flow path 40), making it possible to make the amount of coolant flowing through the fifth coolant flow path 35 and the amount of coolant flowing through the tenth coolant flow path 40 equal to each other.

[0060] In this case, it is preferable to use a check valve 55 capable of adjusting the flow rate, and to provide a flow sensor (e.g., a “first flow sensor”) that detects the amount of coolant flowing through the second coolant flow path 32 and a flow sensor (e.g., a “second flow sensor”) that detects the amount of coolant flowing through the seventh coolant flow path 37. This makes it possible to set the flow rate of coolant that can flow through the check valve 55 based on the detection results of the first and second flow sensors, thereby making it possible to configure the amount of coolant flowing through the fifth coolant flow path 35 and the amount of coolant flowing through the tenth coolant flow path 40 to be equal to each other. Note that it is also possible to provide a flow sensor (e.g., a “third flow sensor”) that detects the amount of coolant flowing through the fifth coolant flow path 35 and a flow sensor (e.g., a “fourth flow sensor”) that detects the amount of coolant flowing through the tenth coolant flow path 40, and adjust the flow rate of coolant flowing through the check valve 55 so that the detection results of the third flow sensor and the fourth flow sensor are equal to each other.

[0061] Furthermore, the third switching valve 53 is set to a state in which the coolant from the fourth coolant flow path 34 flows to the fifth coolant flow path 35 and the twelfth coolant flow path 42 .

[0062] As a result, the coolant is circulated by the first pump P1 through the first coolant flow path 31, the water-cooled condenser 12, the second coolant flow path 32, the first switching valve 51, the seventh coolant flow path 37, the radiator 54, the eleventh coolant flow path 41, and the ninth coolant flow path 39. The coolant is circulated by the second pump P2 through the third coolant flow path 33, the chiller 14, the fourth coolant flow path 34, the third switching valve 53, the twelfth coolant flow path 42, the cooler core 62, and the thirteenth coolant flow path 43. Furthermore, the coolant flowing through each of the second coolant flow path 32 and the fifth coolant flow path 35 is divided by the first switching valve 51 and merges in the sixth coolant flow path 36, flows through the heater core 63 and the eighth coolant flow path 38 to the second switching valve 52, and is then divided into the ninth coolant flow path 39 and the tenth coolant flow path 40. The coolant diverted to the ninth coolant flow path 39 returns to the first pump P1, and the coolant diverted to the tenth coolant flow path 40 returns to the second pump P2. In Figure 6, the flow state of a coolant with a relatively high temperature is indicated by a dashed arrow, and the flow state of a coolant with a relatively low temperature is indicated by a broken arrow. Also, the flow state of a coolant that is a mixture of a coolant with a relatively high temperature and a coolant with a relatively low temperature is indicated by a dashed arrow.

[0063] Therefore, the heat of the coolant discharged from the water-cooled condenser 12 is partially dissipated in the radiator 54, and the heat of the coolant discharged from the chiller 14 is utilized for heat exchange with the air in the cooler core 62 and the heater core 63. In this second state, the HVAC unit 4 performs a cooling reheat operation in accordance with the set temperature of the air conditioner. The cooling reheat operation refers to an operation in which the cooler core 62 cools the air to remove moisture (after reducing humidity), and then the cooled air is reheated in the heater core 63 before being introduced into the passenger compartment 5.

[0064] In the state A in the first state described above, it is preferable to adjust the amount of coolant delivered from the chiller 14 relative to the amount of coolant delivered from the water-cooled condenser 12 in accordance with the set temperature of the air conditioning and heating in the passenger compartment 5. In other words, the higher the set temperature of the air conditioning and heating in the passenger compartment 5, the more the amount of coolant delivered from the water-cooled condenser 12 should be increased and the more the amount of coolant delivered from the chiller 14 should be reduced.

[0065] In addition, in state B of the first state, not only is the amount of coolant delivered from the chiller 14 adjusted relative to the amount of coolant delivered from the water-cooled condenser 12 in accordance with the set temperature of the air conditioning and heating in the passenger compartment 5, but the amount of coolant delivered from the first switching valve 51 to the radiator 54 in accordance with the amount of coolant delivered from the first switching valve 51 to the heater core 63 in accordance with the set temperature of the air conditioning and heating in the passenger compartment 5 is also adjusted.

[0066] Furthermore, in state C of the first state, it is preferable to adjust the amount of coolant discharged from the chiller 14 relative to the amount of coolant discharged from the water-cooled condenser 12 in accordance with the set temperature of the air conditioning and heating in the passenger compartment 5. In other words, the lower the set temperature of the air conditioning and heating in the passenger compartment 5, the more preferably the amount of coolant discharged from the water-cooled condenser 12 is reduced and the amount of coolant discharged from the chiller 14 is increased.

[0067] Furthermore, in the second state, not only is the amount of coolant delivered from the chiller 14 relative to the amount of coolant delivered from the water-cooled condenser 12 adjusted in accordance with the set temperature of the air conditioning and heating in the passenger compartment 5, but the amount of coolant flowing from the second coolant flow path 32 to the sixth coolant flow path 36 and the amount of coolant flowing from the fifth coolant flow path 35 to the sixth coolant flow path 36 may also be adjusted in accordance with the set temperature of the air conditioning and heating in the passenger compartment 5. That is, in the second state, the flow rate of coolant flowing from the water-cooled condenser 12 to the heater core 63 and the flow rate of coolant flowing from the chiller 14 to the heater core 63 may be adjusted in accordance with the set temperature of the air conditioning and heating in the passenger compartment 5. Specifically, for example, when the set temperature for heating and cooling the passenger compartment 5 is relatively high, the ratio of the flow rate of coolant flowing from the chiller 14 to the heater core 63 to the flow rate of coolant flowing from the water-cooled condenser 12 to the heater core 63 can be reduced to increase the temperature of the heater core 63, thereby improving the heating efficiency and / or speeding up the heating; when the set temperature for heating and cooling the passenger compartment 5 is relatively low, the ratio of the flow rate of coolant flowing from the chiller 14 to the heater core 63 to the flow rate of coolant flowing from the water-cooled condenser 12 to the heater core 63 can be increased to prevent the air from being reheated too much in the heater core 63.

[0068] The amount of coolant can be adjusted by changing the openings of the first selector valve 51, the second selector valve 52, and the third selector valve 53. It can also be adjusted by changing the discharge rates of the first pump P1 and the second pump P2.

[0069] As described above, when the HVAC unit 4 performs heating operation or dehumidifying heating operation, the flow state of the coolant in the coolant flow path 3A becomes state A in the first state, when the HVAC unit 4 performs dehumidifying heating operation, the flow state of the coolant in the coolant flow path 3A becomes state B in the first state, and when the HVAC unit 4 performs cooling operation, the flow state of the coolant in the coolant flow path 3A becomes state C in the first state. Also, when the HVAC unit 4 performs cooling reheat operation, the flow state of the coolant in the coolant flow path 3A becomes the second state.

[0070] On the other hand, as described above, the amount of coolant delivered from the chiller 14 and the amount of coolant delivered from the water-cooled condenser 12 can be controlled by changing the openings of the first selector valve 51, the second selector valve 52, and the third selector valve 53 and the discharge rates of the first pump P1 and the second pump P2. Therefore, when the HVAC unit 4 performs cooling operation, the flow state of the coolant in the coolant flow path 3A is not only state C in the first state, but may also be state B in the first state depending on, for example, the outside air temperature and the set temperature for cooling.

[0071] Furthermore, in the HVAC unit 4, outside air drawn in by the blower 61 is sent to the cooler core 62 and introduced into the passenger compartment 5 via the heater core 63. Therefore, depending on the operating state of the HVAC unit 4 and the state of the vehicle before the air-conditioning operation is started, there are cases where sufficiently cooled coolant is not circulating in the heater core 63, and there is a possibility that the outside air cooled by the cooler core 62 will warm up in the heater core 63. For this reason, it takes time for the temperature of the air introduced into the passenger compartment 5 from the HVAC unit 4 to reach the set temperature for air conditioning, and there are also cases where it is necessary to increase the air-conditioning capacity (increase the workload of the compressor 11) to shorten this time.

[0072] Therefore, in the vehicle air conditioning system 1, when the HVAC unit 4 performs cooling operation, the vehicle interior 5 can be quickly cooled even if the flow state of the coolant in the coolant flow path 3A is in state B or state C in the first state.

[0073] Specifically, when switching to cooling operation in the passenger compartment 5, the operation is switched to a first state in which the coolant from the chiller 14 flows through the heater core 63. That is, when an operation is performed to cool the passenger compartment 5, the flow state of the coolant in the coolant flow path 3A is switched to state C in the first state, regardless of the state before the operation (see FIG. 5).

[0074] 5 , the coolant discharged from the water-cooled condenser 12 flows through the radiator 54 via the first selector valve 51 and returns to the water-cooled condenser 12 without flowing through the heater core 63. The coolant discharged from the chiller 14 is also discharged to the cooler core 62 via the third selector valve 53, and is also discharged to the first selector valve 51. The coolant discharged from the third selector valve 53 to the first selector valve 51 is then discharged to the heater core 63 without flowing through the radiator 54. As a result, the coolant remaining in the heater core 63 before the air-conditioning operation is pushed out by the coolant cooled by the chiller 14, and coolant of approximately the same temperature as the coolant flowing through the cooler core 62 flows, making it possible to prevent the outside air cooled by the cooler core 62 from warming up in the heater core 63.

[0075] The coolant that has flowed through the heater core 63 is returned to the chiller 14. That is, as shown in Fig. 5, the coolant that has flowed through the heater core 63 is sent only to the second pump P2 side by the second switching valve 52. As a result, the coolant merges with the cooler core 62 and is returned to the chiller 14, where it is cooled by heat exchange with the refrigerant flowing through the refrigerant flow path 2A.

[0076] 7 shows the change in temperature (blowing temperature) of the wind (air) blown (introduced) into the passenger compartment 5 when such control is performed when switching to cooling operation in the passenger compartment 5. In FIG. 7, the vertical axis represents the blowing temperature (°C) and the horizontal axis represents time (seconds).

[0077] As shown in A of Figure 7, when the operation mode is switched to cooling at time t0, the blowing temperature is T5, and after time p11 from time t0, it reaches T3 (where T3<T5). After that, after time p12 from time t0 (where p11<p12), it reaches T2 (where T2<T3), and after time p13 from time t0 (where p12<p13), it reaches T1 (where T1<T2). Finally, it reaches the set temperature S1.

[0078] In contrast, in a conventional configuration in which an air mix door is provided between the cooler core and heater core, and a relatively high-temperature coolant flows through the heater core during cooling, but the air mix door blocks the air from the cooler core so that it does not enter the heater core, as shown in B of Figure 7, the temperature reaches T3 after p21 (p11 = p21) from t0, T2 after p22 (where p21 < p22, p12 < p22) from t0, and T1 after p23 (where p22 < p23, p13 < p23) from t0. Eventually, a temperature close to the set temperature S1 is reached.

[0079] Furthermore, in the case where an air mix door is not provided between the cooler core and the heater core and coolant does not flow through the heater core during cooling, as shown in C of Figure 7, the temperature reaches T3 after time t0 to time p31 (p21<p31), T2 after time t0 to time p32 (where p31<p32, p22<p32), and T1 after time t0 to time p33 (where p32<p33, p23<p33).Finally, the temperature reaches a value close to the set temperature S1.

[0080] As shown in Figure 7, when switching to cooling operation as described above, by switching the flow state of the coolant in the coolant flow path 3A to state C in the first state, it becomes possible to quickly make the blown-out temperature reach the desired set temperature S1, compared to a configuration in which an air mix door is provided between the cooler core and the heater core, and a relatively high-temperature coolant flows through the heater core during cooling, while the air mix door blocks the wind from the cooler core so that it is not introduced into the heater core, or a configuration in which a mix door is not provided between the cooler core and the heater core, and coolant is not circulated through the heater core during cooling.

[0081] Note that when switching to cooling operation, the control of switching the flow state of the coolant in the coolant flow path 3A to state C in the first state does not always need to be performed. For example, the vehicle air conditioning system 1 may be configured to set the operation mode to a "rapid cooling mode" for performing rapid cooling, and when such a rapid cooling mode is selected, the control of switching to state C in the first state may be performed. Also, the vehicle air conditioning system 1 may be configured to set the operation mode to an "energy saving mode" for performing energy saving operation, and when such an energy saving mode is selected, the control of switching to state C in the first state may not be performed.

[0082] By configuring the vehicle air conditioning system 1 as described above, in state B of the first state, the temperature of the coolant is adjusted as much as possible by the radiator 54, and when it becomes impossible to adjust the temperature of the coolant by the radiator 54, as in state C and the second state of the first state, the temperature of the coolant can be adjusted by circulating the coolant sent from the chiller 14 not only through the cooler core 62 but also through the heater core 63. If the coolant sent from the chiller 14 is circulated not only through the cooler core 62 but also through the heater core 63, the power consumption of the compressor 11 increases.

[0083] Here, the coolant discharged from the chiller 14 merges with the coolant discharged from the water-cooled condenser 12, and the temperature of the coolant becomes higher than the temperature of the coolant before being introduced into the chiller 14. The heated coolant is cooled in the chiller 14, but to lower the temperature of the coolant in the chiller 14, it is necessary to reduce the pressure of the refrigerant in the chiller 14. The pressure of the refrigerant in the chiller 14 can be reduced by adjusting the opening of the expansion valve 13. However, a reduction in the pressure of the refrigerant in the chiller 14 increases the workload of the compressor 11, resulting in increased power consumption by the compressor 11. Therefore, by cooling the coolant as much as possible using the radiator 54, it is possible to reduce the power consumption of the compressor 11. Furthermore, when switching to cooling operation, it is possible to quickly reach the desired set temperature S1 for the outlet air temperature.

[0084] Other Embodiments Next, other embodiments of the vehicle air conditioning system 1 will be described.

[0085] In the above embodiment, the state in which the coolant flows through the coolant flow path 3A is switched between the first state and the second state based on the state of the radiator 54. However, the switching between the first state and the second state may be configured to be switched regardless of the state of the radiator 54.

[0086] In the above embodiment, the state of the radiator 54 is described as being determined by at least one of the outside air temperature, the set temperature of the air conditioner, the temperature of the coolant, the flow rate of the coolant, and the amount of outside air introduced into the radiator 54. However, the state of the radiator 54 can also be determined based on information other than these (for example, the type of coolant or the cooling capacity of the radiator 54).

[0087] In the above embodiment, the vehicle air conditioning system 1 is described as further including the cooler core 62 for performing heat exchange between the air and the coolant from the chiller 14 in order to perform heating and cooling. However, it is also possible to configure the system without the cooler core 62. In this case, when the HVAC unit 4 performs cooling operation, it is possible to configure the system so that the air is cooled only by the heater core 63.

[0088] In the above embodiment, in the second state, it has been described that the coolant that has flowed through the heater core 63 is configured so that the amount of coolant that is the same as the amount of coolant that has flowed from the chiller 14 to the heater core 63 joins the coolant that has flowed through the cooler core 62. However, in the second state, it may be configured so that the amount of coolant that has flowed through the heater core 63 that is different from the amount of coolant that has flowed from the chiller 14 to the heater core 63 joins the coolant that has flowed through the cooler core 62.

[0089] In the above embodiment, the first switching valve 51 is used to switch between the first and second states of coolant flow through the coolant flow path 3A. However, instead of the first switching valve 51, multiple pumps (e.g., three) may be provided. In this case, a radiator pump may be provided between the second coolant flow path 32 and the seventh coolant flow path 37, a hot water pump may be provided between the second coolant flow path 32 and the sixth coolant flow path 36, and a cold water pump may be provided between the fifth coolant flow path 35 and the sixth coolant flow path 36. Furthermore, check valves may be provided downstream of the hot water pump and the cold water pump before they merge. Even with this configuration, switching between the first and second states is possible.

[0090] In the above embodiment, the water-cooled condenser 12 is used as the condenser. However, an air-cooled condenser provided near the radiator 54 may also be used.

[0091] [Outline of the above embodiment] Hereinafter, an outline of the vehicle air conditioning system 1 described above will be described.

[0092] (1) The vehicle air conditioning system 1 includes a refrigerant flow path 2A that circulates refrigerant between a water-cooled condenser 12 (condenser) and a chiller 14 (evaporator), a coolant flow path 3A that circulates coolant that exchanges heat with the refrigerant in the water-cooled condenser 12 and the chiller 14, and a heater core 63 (first heat exchanger) that exchanges heat between air and the coolant to cool or heat the passenger compartment 5. The state in which the coolant flows through the coolant flow path 3A can be switched between a first state in which coolant from either the water-cooled condenser 12 or the chiller 14 flows through the heater core 63, and a second state in which coolant from both the water-cooled condenser 12 and the chiller 14 flows through the heater core 63.

[0093] According to this configuration, when the situation allows for adjustment of the temperature of the cooling liquid, the cooling liquid from either the water-cooled condenser 12 or the chiller 14 is circulated through the cooling liquid flow path 3A, and the temperature of the cooling liquid is adjusted as necessary; when the situation makes it difficult to adjust the temperature of the cooling liquid, the cooling liquid from both the water-cooled condenser 12 and the chiller 14 is mixed to adjust the temperature of the cooling liquid.

[0094] (2) In the vehicle air conditioning system 1 described in (1), the first state and the second state are switched based on the state of the radiator 54 that exchanges heat between the coolant and the outside air, and it is preferable that the state of the radiator 54 is determined by at least one of the outside air temperature, the set temperature of the air conditioner, the coolant temperature, the flow rate of the coolant, and the amount of outside air introduced into the radiator 54.

[0095] According to this configuration, the state in which the coolant flows through the coolant flow path 3A can be switched between situations in which the radiator 54 can regulate the temperature of the coolant and situations in which it is difficult to regulate the temperature. Therefore, power saving is possible based on the status of the radiator 54. Furthermore, according to this configuration, it is possible to easily determine whether the radiator 54 can regulate the temperature of the coolant. Therefore, it is possible to appropriately determine whether it is necessary to regulate the temperature of the coolant by mixing the coolants from both the water-cooled condenser 12 and the chiller 14. Furthermore, although switching the state in which the coolant flows through the coolant flow path 3A increases power consumption, according to this configuration, the radiator 54 regulates the temperature of the coolant as much as possible until the radiator 54 can no longer regulate the temperature of the coolant and switches from the first state to the second state, thereby enabling low power consumption.

[0096] (3) In the vehicle air conditioning system 1 described in (1) or (2), it is preferable to further include a cooler core 62 (second heat exchanger) that exchanges heat between the air and the coolant from the chiller 14 to perform heating and cooling.

[0097] According to this configuration, it is possible to introduce air cooled in the cooler core 62 into the passenger compartment 5 .

[0098] (4) In the vehicle air conditioning system 1 described in (3), in the second state, it is preferable that the amount of coolant that has flowed through the heater core 63 is equal to the amount of coolant that has flowed from the chiller 14 to the heater core 63, and that amount is configured to merge with the coolant that has flowed through the cooler core 62.

[0099] According to this configuration, the same amount of coolant as that which flows from the chiller 14 to the heater core 63 can be returned to the chiller 14, thereby maintaining the flow balance of the coolant in the coolant flow path 3A.

[0100] (5) In the vehicle air conditioning system 1 described in any one of (1) to (4), when switching to cooling operation in the passenger compartment 5, it is preferable that the system be switched to a first state in which coolant from the chiller 14 flows through the heater core 63, and that the coolant after flowing through the heater core 63 be returned to the chiller 14.

[0101] According to this configuration, when the operation mode is switched to cooling mode, the flow state of the coolant in the coolant flow path 3A is switched to state C in the first state, so that the coolant remaining in the heater core 63 before the cooling mode is pushed out by the coolant cooled by the chiller 14, and coolant of a temperature approximately the same as that of the coolant flowing through the cooler core 62 flows, making it possible to prevent the outside air cooled by the cooler core 62 from warming up in the heater core 63. Therefore, it is possible to quickly make the temperature of the air outlet (air outlet temperature) provided in the passenger compartment 5 reach the desired set temperature.

[0102] (6) In the vehicle air conditioning system 1 described in any one of (1) to (5), in the second state, it is preferable that the flow rate of the coolant flowing from the water-cooled condenser 12 to the heater core 63 and the flow rate of the coolant flowing from the chiller 14 to the heater core 63 are adjusted according to the set temperature of the heating and cooling of the passenger compartment 5.

[0103] According to this configuration, for example, when the set temperature for heating and cooling the passenger compartment 5 is relatively high, the ratio of the flow rate of coolant flowing from the chiller 14 to the heater core 63 to the flow rate of coolant flowing from the water-cooled condenser 12 to the heater core 63 is reduced, making it difficult for the temperature of the heater core 63 to drop and improving heating efficiency; when the set temperature for heating and cooling the passenger compartment 5 is relatively low, the ratio of the flow rate of coolant flowing from the chiller 14 to the heater core 63 to the flow rate of coolant flowing from the water-cooled condenser 12 to the heater core 63 is increased, preventing the air from being reheated too much and suppressing a deterioration in cooling efficiency.

[0104] The technology according to the present disclosure can be used in a vehicle air conditioning system that cools and heats the interior of a vehicle.

[0105] 1: Vehicle air conditioning system, 2A: Refrigerant flow path, 3A: Coolant flow path, 5: Vehicle compartment, 12: Water-cooled condenser (condenser), 14: Chiller (evaporator), 54: Radiator, 62: Cooler core (second heat exchanger), 63: Heater core (first heat exchanger)

Claims

1. A vehicle air conditioning system comprising: a refrigerant flow path that circulates refrigerant through a condenser and an evaporator; a coolant flow path that circulates coolant that exchanges heat with the refrigerant in the condenser and the evaporator; and a first heat exchanger that exchanges heat between air and the coolant to cool or heat the vehicle interior, wherein the state in which the coolant flows through the coolant flow path can be switched between a first state in which the coolant from one of the condenser and the evaporator flows through the first heat exchanger, and a second state in which the coolant from both the condenser and the evaporator flows through the first heat exchanger.

2. A vehicle air conditioning system as described in claim 1, wherein the first state and the second state are switched based on the state of a radiator that exchanges heat between the coolant and outside air, and the state of the radiator is determined by at least one of the temperature of the outside air, the set temperature of the air conditioning / heating system, the temperature of the coolant, the flow rate of the coolant, and the amount of outside air introduced into the radiator.

3. The vehicle air conditioning system according to claim 1 or 2, further comprising a second heat exchanger that exchanges heat between air and the coolant from the evaporator to perform the heating and cooling.

4. A vehicle air conditioning system as described in claim 3, wherein in the second state, the amount of coolant that has flowed through the first heat exchanger is equal to the amount of coolant that has flowed from the evaporator to the first heat exchanger, and merges with the coolant that has flowed through the second heat exchanger.

5. A vehicle air conditioning system as described in claim 1 or 2, wherein when switching to cooling operation in the passenger compartment, the system is switched to the first state in which the coolant from the evaporator flows through the first heat exchanger, and the coolant after flowing through the first heat exchanger is returned to the evaporator.

6. A vehicle air conditioning system as described in claim 1 or 2, wherein in the second state, the flow rate of the coolant circulating from the condenser to the first heat exchanger and the flow rate of the coolant circulating from the evaporator to the first heat exchanger are adjusted according to the set temperature of the heating and cooling of the passenger compartment.

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