Vehicle air conditioning unit

Abstract

This allows hydrocarbon-based refrigerants that have entered the coolant circuit to be released from the coolant circuit outside the vehicle's interior. [Solution] The onboard air conditioning system comprises a refrigerant circuit R, a coolant circuit C2, and an air conditioning unit 70. The refrigerant circuit R has a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator 26a for heat absorption, through which a hydrocarbon refrigerant circulates. A heat exchanger 40 is integrally configured with the evaporator 26a of the refrigerant circuit R, and the refrigerant in the evaporator 26a cools the coolant. The coolant circuit C2 circulates the coolant and supplies it to the cooler core 72. The air conditioning unit 70 has an air passage 75 in which the cooler core 72 is located, and the cooler core 72 cools the air passing through the air passage 75 and blows it into the passenger compartment. The coolant circuit C2 includes a gas-liquid separator 100 and a relief valve 102. The relief valve 102 is located on the outside of the passenger compartment, above the gas-liquid separator 100, and opens when the pressure inside the gas-liquid separator 100 rises.

Description

Technical Field

[0001] This specification relates to an in-vehicle air conditioner, and particularly discloses an in-vehicle air conditioner using a hydrocarbon refrigerant.

Background Art

[0002] In recent years, as a refrigerant for air conditioners, the use of hydrocarbon refrigerants (HC refrigerants) such as propane with a low global warming potential has been considered. Since HC refrigerants are flammable, configurations for preventing refrigerant leakage and ensuring safety in case of refrigerant leakage have been studied.

[0003] Patent Document 1 discloses the use of propane as a refrigerant for a vehicle air conditioner. The air conditioner in this document installs the refrigeration circuit in the engine room, partitions the space between the engine room and the passenger compartment with a partition wall, and uses a heat pipe penetrating the partition wall to transfer the cooling capacity of the refrigeration circuit to the passenger compartment, so that even if the refrigerant leaks from the refrigeration circuit, the refrigerant does not flow into the passenger compartment.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In an in-vehicle air conditioner, in addition to the refrigerant circuit for the hydrocarbon refrigerant, a coolant circuit through which the coolant cooled by the refrigerant circuit circulates is provided, and a configuration in which the air blown into the passenger compartment is cooled using the coolant in the coolant circuit can be considered.

[0006] Specifically, a refrigerant circuit is provided through which a hydrocarbon refrigerant circulates, comprising a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption. A heat exchanger is also provided, integrated with the evaporator of the refrigerant circuit, to cool the coolant liquid using the refrigerant in the evaporator. Furthermore, a coolant circuit is provided to circulate this coolant and supply it to the cooler core, which in turn cools the air blown into the passenger compartment. With this configuration, since the refrigerant circuit of the hydrocarbon refrigerant is not located in the passage for the air blown into the passenger compartment, the risk of hydrocarbon refrigerant leaking into the passenger compartment can be reduced.

[0007] In this system, the heat exchanger exchanges heat between the hydrocarbon refrigerant and the coolant. If this heat exchanger is damaged due to deterioration or other reasons, the hydrocarbon refrigerant may flow into the coolant circuit. Even if the hydrocarbon refrigerant flows into the coolant circuit, a configuration is desired that allows the hydrocarbon refrigerant that has entered the coolant circuit to be released from the coolant circuit outside the passenger compartment, thereby reducing the risk of the hydrocarbon refrigerant leaking into the passenger compartment.

[0008] This specification discloses an on-board air conditioning system that enables the release of hydrocarbon-based refrigerants that have flowed into the coolant circuit from the coolant circuit outside the vehicle compartment. [Means for solving the problem]

[0009] The in-vehicle air conditioning system disclosed herein comprises a refrigerant circuit through which a hydrocarbon refrigerant circulates, having a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption; a heat exchanger integrated with the evaporator of the refrigerant circuit for cooling a coolant with the refrigerant in the evaporator; a coolant circuit through which the coolant circulates, having a cooler core; and an air conditioning unit having an air passage in which the cooler core is located, for cooling the air passing through the air passage with the cooler core and blowing it into the passenger compartment, wherein the coolant circuit includes a gas-liquid separator and a relief valve, the relief valve being located above the gas-liquid separator outside the passenger compartment and opening when the pressure inside the gas-liquid separator rises.

[0010] In this configuration, when hydrocarbon refrigerant flows into the coolant circuit, the gaseous hydrocarbon refrigerant is collected in the gas-liquid separator, causing the pressure inside the separator to rise. This opens the relief valve, allowing the hydrocarbon refrigerant in the gas-liquid separator to be released from the coolant circuit outside the vehicle compartment.

[0011] In the vehicle air conditioning system of the present disclosure, the coolant circuit may further include a hose connected to the exhaust port of the relief valve and extending downward to the vehicle.

[0012] With this configuration, when the relief valve opens, the hydrocarbon refrigerant can be guided through the hose to the underside of the vehicle.

[0013] In the vehicle air conditioning system of the present disclosure, the coolant circuit further includes a pressure sensor for detecting the pressure in the piping of the coolant circuit, and solenoid valves disposed on the upstream and downstream sides of the coolant circuit outside the passenger compartment, and the vehicle air conditioning system further includes a controller, the controller controlling the two solenoid valves to a closed state when the value detected by the pressure sensor becomes higher than a predetermined value, and otherwise maintaining the two solenoid valves in an open state.

[0014] With this configuration, when hydrocarbon refrigerant flows into the coolant circuit, the pressure in the piping of the coolant circuit increases, causing the two solenoid valves to be closed. This prevents the hydrocarbon refrigerant from flowing into the part of the coolant circuit located on the passenger compartment side.

[0015] In the in-vehicle air conditioning system of the present disclosure, when the controller controls the two solenoid valves to be in a closed state, at least one of the two solenoid valves may open to function as a relief valve when the pressure in the coolant circuit on the cooler core side rises above the pressure of the two solenoid valves.

[0016] According to this configuration, when the two solenoid valves are controlled to be in the closed state and the pressure in the coolant circuit on the cooler core side rises more than that of the two solenoid valves due to vaporization of the coolant or the like, at least one of the two solenoid valves opens, so that piping breakage in the coolant circuit on the cooler core side can be prevented.

[0017] In the in-vehicle air conditioner of the present disclosure, the hydrocarbon-based refrigerant may be propane or a refrigerant mainly composed of propane.

[0018] The vehicle disclosed in this specification includes the above in-vehicle air conditioner.

Advantages of the Invention

[0019] According to the technology disclosed in this specification, the hydrocarbon-based refrigerant flowing into the coolant circuit can be discharged from the coolant circuit outside the vehicle compartment.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic diagram showing the configuration of the air conditioner. [Figure 2] It is a schematic diagram showing the arrangement of the air conditioner in the vehicle. [Figure 3] It is a diagram showing the configuration of the second coolant circuit. [Figure 4] It is a diagram showing a state where the hydrocarbon-based refrigerant flows into the second coolant circuit. [Figure 5] It is a diagram showing a state where the coolant leaks from the second coolant circuit. [Figure 6] It is a diagram showing the configuration of another second coolant circuit. [Figure 7] It is a schematic diagram showing the configuration of another air conditioner.

Embodiments for Carrying Out the Invention

[0021] <Preface> The embodiments will be described below with reference to the drawings. In all drawings, equivalent elements are denoted by the same reference numerals, and redundant explanations are omitted. In the following description, unless otherwise specified, terms indicating directions and orientations such as front, back, left, right, up, and down refer to directions and orientations related to the vehicle. In Figure 2 described below, the direction of the arrow FR indicates forward, and the direction of the arrow UP indicates upward.

[0022] The air conditioning system is installed in a vehicle such as an automobile. In each embodiment described below, the type of vehicle in which the air conditioning system is installed is not limited. For example, the vehicle may be an engine-powered automobile or an electric vehicle powered by a motor. The vehicle may also be a hybrid electric vehicle or a plug-in hybrid electric vehicle equipped with both an engine and a motor. Furthermore, the vehicle may be a fuel cell vehicle equipped with a fuel cell or a battery electric vehicle that runs on electricity stored in a battery.

[0023] The air conditioning system includes a refrigerant circuit through which a hydrocarbon refrigerant (referred to as an HC refrigerant) circulates. HC refrigerants are flammable. Examples of HC refrigerants include propane, butane, isobutane, ethane, ethylene, and propylene. In the refrigerant circuit, one of these HC refrigerants, or a mixture of two or more of these HC refrigerants, may be used. Alternatively, a mixed refrigerant may be used in the refrigerant circuit, which mainly consists of one or more HC refrigerants, as well as refrigerants other than HC refrigerants and various additives. For example, in the refrigerant circuit, propane, or a refrigerant mainly consisting of propane, containing at least one of other refrigerants and additives (a refrigerant mainly composed of propane), may be used. An example of an HC refrigerant may be R290. In this specification, hydrocarbon refrigerant (HC refrigerant) means a pure hydrocarbon refrigerant or a refrigerant mainly composed of a hydrocarbon refrigerant.

[0024] The refrigerant circuit serves as the heat source for the air conditioning system. The refrigerant circuit comprises, in order along the direction of refrigerant flow, a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption. A receiver may be provided between the condenser and the expansion valve. An accumulator may also be provided between the evaporator and the compressor.

[0025] An air conditioning system may include a high-temperature coolant circuit through which a coolant heated by a condenser in the refrigerant circuit circulates, and a low-temperature coolant circuit through which a coolant cooled by an evaporator in the refrigerant circuit circulates. The coolant is a heat transfer medium, and the high-temperature coolant circuit and the low-temperature coolant circuit are heat transfer medium circuits, respectively.

[0026] In the embodiments described below, as shown in Figure 1, the air conditioning system 12 includes a first coolant circuit C1 as a high-temperature coolant circuit and second and third coolant circuits C2 and C3 as low-temperature coolant circuits. The air conditioning system 12 can be configured without the third coolant circuit C3, which will be explained with reference to Figure 7.

[0027] The coolant in the first to third coolant circuits C1, C2, and C3 may be coolant water. That is, the coolant may be water without additives, water mixed with additives such as antifreeze or preservatives, or coolant fluid. Furthermore, the coolant may also be a liquid heat transfer medium such as oil, and is not limited to that.

[0028] In the embodiments described below, the refrigerant circuit is located under the vehicle's front hood. Hereafter, regardless of the presence or type of power source (engine, motor, etc.) under the front hood, the area under the front hood will be referred to as the "engine room".

[0029] <Embodiment> Figure 1 is a schematic diagram showing the configuration of the air conditioning system 12 according to an embodiment. Figure 2 is a schematic diagram showing the arrangement of the air conditioning system 12 inside the vehicle. The vehicle 10 is equipped with a battery 54 that supplies power to a motor as a power source. The vehicle 10 may be, for example, a battery electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc.

[0030] The air conditioning unit 12 provides air conditioning to the vehicle compartment 90 and also cools the battery 54. The air conditioning unit 12 may also be configured to cool other in-vehicle equipment, such as a PCU (Power Control Unit), along with the battery 54, or in place of the battery 54.

[0031] As shown in Figure 1, the air conditioning system 12 comprises a refrigerant circuit R which serves as a heat source, first to third coolant circuits C1, C2, and C3, and an air conditioning unit 70. The first coolant circuit C1 circulates a first coolant heated by the refrigerant in the refrigerant circuit R. The second coolant circuit C2 circulates a second coolant cooled by the refrigerant in the refrigerant circuit R. Similarly, the third coolant circuit C3 circulates a third coolant cooled by the refrigerant in the refrigerant circuit R. The air conditioning unit 70 supplies air cooled by the second coolant circulating in the second coolant circuit C2 into the vehicle cabin.

[0032] The refrigerant circuit R is a closed circuit that circulates an HC-based refrigerant (hereinafter also simply referred to as refrigerant) by sequentially connecting a compressor 20, a condenser 22, a receiver 28, expansion valves 24a and 24b, and evaporators 26a and 26b via refrigerant piping. The expansion valve 24a and evaporator 26a are connected in series, and similarly, the expansion valve 24b and evaporator 26b are connected in series. The refrigerant flow paths of the expansion valve 24a and evaporator 26a and the refrigerant flow paths of the expansion valve 24b and evaporator 26b are connected in parallel.

[0033] The air conditioning unit 12 includes a heat exchanger 30. The heat exchanger 30 is integrated with the condenser 22 of the refrigerant circuit R and exchanges heat between the refrigerant of the refrigerant circuit R and the first coolant of the first coolant circuit C1. The heat exchanger 30 is a water-cooled condenser and may be, for example, a plate heat exchanger. The heat exchanger 30 is the first heat exchanger.

[0034] The first coolant circuit C1 is a closed circuit that circulates the first coolant, consisting of a water pump 32, a heat exchanger 30, and a radiator 34 connected sequentially by coolant piping. The radiator 34 is a heat exchanger that exchanges heat between the first coolant and the vehicle's airflow Wtr. In the first coolant circuit C1, the first coolant, pressurized by the water pump 32, becomes hot due to heat dissipation from the refrigerant in the condenser 22 of the refrigerant circuit R as it passes through the heat exchanger 30. The hot first coolant is then sent to the radiator 34, where it is cooled by the vehicle's airflow Wtr.

[0035] Furthermore, the air conditioning unit 12 includes a heat exchanger 40. The heat exchanger 40 is integrated with the evaporator 26a of the refrigerant circuit R and exchanges heat between the refrigerant of the refrigerant circuit R and the second coolant of the second coolant circuit C2. The heat exchanger 40 may be, for example, a plate heat exchanger. The heat exchanger 40 is the second heat exchanger.

[0036] The second coolant circuit C2 is a closed circuit that circulates the second coolant, with the water pump 42, heat exchanger 40, and cooler core 72 sequentially connected by coolant piping. The cooler core 72 is a heat exchanger located in the air passage 75 of the air conditioning unit 70, which exchanges heat between the second coolant and the conditioned air (Wac). In the second coolant circuit C2, the second coolant, pressurized by the water pump 42, becomes cold due to the heat absorption of the refrigerant in the evaporator 26a of the refrigerant circuit R as it passes through the heat exchanger 40. The cold second coolant is then sent to the cooler core 72, where it cools the conditioned air (Wac).

[0037] Furthermore, the air conditioning unit 12 includes a heat exchanger 50. The heat exchanger 50 is integrated with the evaporator 26b of the refrigerant circuit R and exchanges heat between the refrigerant of the refrigerant circuit R and the third coolant of the third coolant circuit C3. The heat exchanger 50 may be, for example, a plate heat exchanger. The heat exchanger 50 is the third heat exchanger.

[0038] The third coolant circuit C3 is a closed circuit that circulates the third coolant, with the water pump 52, heat exchanger 50, and battery 54 sequentially connected by coolant piping. In the third coolant circuit C3, the coolant pumped by the water pump 52 becomes cold due to the absorption of heat by the refrigerant in the evaporator 26b in the refrigerant circuit R as it passes through the heat exchanger 50. The cold third coolant is then sent to the battery 54 to cool it. In this specification, the third coolant circuit C3 and the third coolant are also referred to as the battery coolant circuit and the battery coolant, respectively.

[0039] In this specification, the expansion valve 24a, evaporator 26a, and heat exchanger 40 are also referred to as the air conditioning expansion valve, air conditioning evaporator, and air conditioning heat exchanger, respectively. Furthermore, the expansion valve 24b, evaporator 26b, and heat exchanger 50 are also referred to as the battery expansion valve, battery evaporator, and battery heat exchanger, respectively.

[0040] In the refrigerant circuit R, the refrigerant circulates as follows: The compressor 20 discharges high-pressure gaseous refrigerant, which dissipates heat and liquefies and condenses in the condenser 22 by exchanging heat with the first coolant of the first coolant circuit C1, which passes through the heat exchanger 30, becoming high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of the condenser 22 is depressurized and expanded by the expansion valve 24a via the receiver 28, becoming low-pressure refrigerant, and flows into the evaporator 26a. The low-pressure refrigerant flowing into the evaporator 26a evaporates by exchanging heat with the second coolant of the second coolant circuit C2, which passes through the heat exchanger 40, becoming gaseous refrigerant, flowing out of the evaporator 26a, and returning to the compressor 20.

[0041] Furthermore, the high-pressure liquid refrigerant flowing out of the condenser 22 is depressurized and expanded by the expansion valve 24b via the receiver 28, becoming low-pressure refrigerant, and flows into the evaporator 26b. The low-pressure refrigerant flowing into the evaporator 26b evaporates by exchanging heat with the third coolant in the third coolant circuit C3 that passes through the heat exchanger 50, becoming gaseous refrigerant, flowing out of the evaporator 26b, and returning to the compressor 20.

[0042] The air conditioning unit 70 comprises a blower 80 and an air passage 75 formed by a case (not shown). Inside the air passage 75, the blower 80, a cooler core 72, and a heater core 74 are arranged in order from the direction of airflow. The heater core 74 is a heat exchanger to which, for example, engine coolant or coolant heated by a PTC heater for water heating is supplied. The heater core 74 may also be configured to be supplied with coolant heated by the heat exchanger 30.

[0043] The blower 80 introduces air into the air passage 75 from an air intake (not shown) and blows this air through the cooler core 72 and heater core 74, thereby supplying temperature-controlled air to the passenger compartment. An air mix door 82 is provided inside the air passage 75, which adjusts the ratio of air that has passed through the cooler core 72 to that which flows to the heater core 74. The air conditioning unit 70 may employ conventional HVAC (Heating, Ventilation, and Air Conditioning) technology.

[0044] As shown in Figure 2, the engine compartment 92 and the passenger compartment 90 are separated by a dashboard 94. An instrument panel (not shown) is provided on the passenger compartment 90 side of the dashboard 94. The air conditioning unit 70 is located between the instrument panel and the dashboard 94.

[0045] The battery 54 is located under the floor of the passenger compartment 90, that is, under the floor panel 96. However, the battery 54 may also be located under the seats or at the rear of the vehicle, and its location is not limited.

[0046] The air conditioning unit 12 includes a controller. This controller may be the same as the controller 110 shown in Figure 6, which will be described later, or it may be a different controller. The controller may consist of a processor and a memory device, and may be, for example, an ECU (Electronic Control Unit). The controller controls the equipment included in the air conditioning unit 12 based on detection information from multiple sensors (temperature sensors that detect outside temperature, inside temperature, and battery temperature, solar radiation sensors, pressure sensors, etc.), and setting information from an operation panel operated by the user. The controller may employ conventional air conditioning control technology.

[0047] The refrigerant circuit R is located in the engine compartment 92, as shown in Figure 2. The first coolant circuit C1 is located in front of the refrigerant circuit R. The refrigerant circuit R may be located behind the collision deformation region at the front of the vehicle. This reduces the collision load applied to the refrigerant circuit R when the vehicle 10 is involved in a head-on collision.

[0048] Figure 3 shows the configuration of the second coolant circuit C2 in more detail. In Figure 3 and Figures 4-6 described below, the thick arrows on the outer circumference of the second coolant circuit C2 (or C2a) indicate the flow direction of the second coolant. Hereafter, the second coolant circuit C2 and the second coolant will be simply referred to as the coolant circuit C2 and the coolant, respectively.

[0049] As shown in Figure 3, the coolant circuit C2 includes a gas-liquid separator 100 and a relief valve 102. The gas-liquid separator 100 is a hollow, box-shaped section created by vertically expanding the internal space of a portion of the upper piping in the coolant circuit C2. The gas-liquid separator 100 separates the coolant from the gas. The separated gas accumulates at the top of the gas-liquid separator 100. The gas-liquid separator 100 is located outside the passenger compartment 90, i.e., inside the engine compartment 92.

[0050] The relief valve 102 is located at the top of the gas-liquid separator 100. The relief valve 102 opens when the pressure inside the gas-liquid separator 100 rises. The relief valve 102 is located in the engine room 92, which is outside the passenger compartment 90.

[0051] The coolant circuit C2 includes a hose 104. The hose 104 is connected to the exhaust port of the relief valve 102 and extends downwards to the vehicle body. The hose 104 is located within the engine compartment 92. The hose 104 is positioned at a distance from heat-generating elements such as the engine, motor, and inverter. The end 105 of the hose 104 is located at the bottom of the vehicle body. The end 105 of the hose 104 may be fixed to a vehicle body structure located at the lower (or bottom) part of the engine compartment 92.

[0052] The heat exchanger 40 comprises a primary side portion 40-1 and a secondary side portion 40-2. The primary side portion 40-1 is the evaporator 26a through which the HC-based refrigerant flows. The secondary side portion 40-2 through which the coolant flows. The internal pressure of the refrigerant circuit R is generally higher than the internal pressure of the coolant circuit C2 (heat transfer medium circuit). Therefore, the internal pressure of the primary side portion 40-1 of the heat exchanger 40 is higher than the internal pressure of its secondary side portion 40-2.

[0053] Next, the effects and advantages of the embodiments described above will be explained.

[0054] Figure 4 shows a case where a damaged section 200 occurs in the partition wall between the primary side section 40-1 and the secondary side section 40-2 of the heat exchanger 40 due to deterioration of the heat exchanger 40. In this case, the HC-based refrigerant from the primary side section 40-1 flows into the secondary side section 40-2. The HC-based refrigerant either flows into the secondary side section 40-2 in the form of a gas, or it turns into sludge after flowing into the secondary side section 40-2. The HC-based refrigerant then flows through the coolant circuit C2 while mixed with the coolant in the coolant circuit C2.

[0055] In this process, the HC-based refrigerant is collected by the gas-liquid separator 100, as shown in Figure 4. The pressure inside the gas-liquid separator 100 increases as the HC-based refrigerant is collected. This causes the relief valve 102 to open, allowing the HC-based refrigerant in the gas-liquid separator 100 to be released outside the coolant circuit C2 via the hose 104. Since HC-based refrigerant is generally heavier than air, it flows downwards through the hose 104. Therefore, the HC-based refrigerant can be released to a relatively safe location at the bottom of the vehicle.

[0056] Figure 5 shows a state in which coolant has leaked from the coolant circuit C2. The figure shows that a damaged section 200 has occurred in the heat exchanger 40, and damaged sections 202 and 204 have occurred in the piping of the coolant circuit C2 and the cooler core 72, respectively. As shown in Figure 5, even if damage to the heat exchanger 40 and damage to the coolant circuit C2 occur simultaneously, according to the embodiment described above, the HC-based refrigerant can be released from the coolant circuit C2 outside the vehicle compartment 90, thus preventing the HC-based refrigerant from leaking into the vehicle compartment 90.

[0057] Furthermore, according to the embodiment described above, when the internal pressure of the coolant circuit C2 increases due to the inflow of HC-based refrigerant into the coolant circuit C2, the relief valve 102 opens, thereby suppressing damage to the piping of the coolant circuit C2 due to the pressure increase.

[0058] Furthermore, the configuration of the gas-liquid separator 100, relief valve 102, and hose 104 described above can also be applied to the first coolant circuit C1 or the third coolant circuit C3.

[0059] <Another coolant circuit> Next, another coolant circuit will be described. Figure 6 shows the configuration of another second coolant circuit C2a. This coolant circuit C2a has a pressure sensor 112 and two solenoid valves 114 and 115 added to the coolant circuit C2 (see Figure 3) described above. The pressure sensor 112 detects the pressure in the piping of the coolant circuit C2. The two solenoid valves 114 and 115 are installed in the piping on the upstream and downstream sides of the cooler core 72 outside the passenger compartment 90 (inside the engine room 92), respectively.

[0060] The air conditioning unit 12 includes a controller 110. The controller 110 consists of a processor and a memory device. The controller 110 receives the detection signal s_P from the pressure sensor 112. The controller 110 also outputs control signals s_B1 and s_B2 from the solenoid valves 114 and 115.

[0061] The controller 110 controls the two solenoid valves 114 and 115 to close when the detection signal s_P from the pressure sensor 112 indicates that the internal pressure of the coolant circuit C2a is higher than a predetermined pressure value, i.e., when HC-based refrigerant flows into the coolant circuit C2a. Otherwise, the controller 110 keeps the two solenoid valves 114 and 115 open. With this configuration, when HC-based refrigerant flows into the coolant circuit C2a, the two solenoid valves 114 and 115 close, preventing the HC-based refrigerant from flowing out to the cooler core 72.

[0062] Furthermore, at least one of the two solenoid valves 114 and 115 may be configured to open (i.e., function as a relief valve) when the internal pressure of the piping on the cooler core 72 side rises while the two solenoid valves 114 and 115 are controlled to be closed by the controller 110. This prevents damage to the piping on the cooler core 72 side when the internal pressure of the piping on the cooler core 72 side rises due to vaporization of the coolant or the like.

[0063] The configuration of the pressure sensor 112, the two solenoid valves 114 and 115, and the controller 110 described above may be applied to the first coolant circuit C1 or the third coolant circuit C3. For example, in the third coolant circuit C3, the two solenoid valves 114 and 115 may be installed in the piping on the upstream and downstream sides of the battery 54 (see Figure 1).

[0064] <Another air conditioning unit> Next, another air conditioning system will be described. Figure 7 is a schematic diagram showing the configuration of another air conditioning system 12a. This air conditioning system 12a is configured by omitting the expansion valve 24b, the third heat exchanger 50, and the third coolant circuit C3 from the air conditioning system 12 described above (see Figure 1). The refrigerant circuit Ra of this air conditioning system 12a is configured by sequentially connecting the compressor 20, condenser 22, receiver 28, expansion valve 24a, and evaporator 26a with refrigerant piping.

[0065] This air conditioning unit 12a is configured not to cool the battery 54 (see Figure 1). The battery 54 may be cooled by a separate cooling device provided in addition to the air conditioning unit 12a. Furthermore, vehicles such as engine-powered vehicles that do not have a battery 54 (a battery that supplies power to the motor) do not require a cooling device for the battery, and therefore this air conditioning unit 12a can be used. The configuration of the coolant circuits C2 and C2a (Figures 3 to 6) described above may also be applied to this air conditioning unit 12a. [Explanation of Symbols]

[0066] 10 Vehicle, 12,12a Air conditioning system, 20 Compressor, 22 Condenser, 24a Expansion valve (Air conditioning expansion valve), 24b Expansion valve (Battery expansion valve), 26a Evaporator (Air conditioning evaporator), 26b Evaporator (Battery evaporator), 28 Receiver, 30 Heat exchanger (First heat exchanger), 32 Water pump, 34 Radiator, 40 Heat exchanger (Second heat exchanger, Air conditioning heat exchanger), 40-1 Primary side section, 40-2 Secondary side section, 42 Water pump, 50 Heat exchanger (Third heat exchanger, Battery heat exchanger), 52 Water pump, 54 Battery, 70 Air conditioning unit, 72 Cooler core, 74 Heater core, 75 Air passage, 80 Blower, 82 Air mix door, 90 92 Car compartment, 94 Engine compartment, 96 Dashboard, 96 Floor panel, 100 Gas-liquid separator, 102 Relief valve, 104 Hose, 105 End, 110 Controller, 112 Pressure sensor, 114, 115 Solenoid valve, 200, 202, 204 Damaged part, R, Ra Refrigerant circuit, C1 First coolant circuit, C2, C2a Second coolant circuit (coolant circuit), C3 Third coolant circuit (battery coolant circuit), Wtr Driving airflow, Wac Air conditioning airflow.

Claims

1. In-vehicle air conditioning system, A refrigerant circuit through which a hydrocarbon refrigerant circulates has a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption, A heat exchanger, which is integrated with the evaporator of the refrigerant circuit and cools the coolant with the refrigerant in the evaporator, A cooler core is provided, and a coolant circuit is provided through which the coolant circulates, The air conditioning unit comprises a cooler core having an air passage located inside, which cools the air passing through the air passage and blows it into the passenger compartment. The cooling fluid circuit includes a gas-liquid separator and a relief valve. The relief valve is located outside the vehicle compartment, above the gas-liquid separator, and opens when the pressure inside the gas-liquid separator rises. In-vehicle air conditioner.

2. An in-vehicle air conditioning system according to claim 1, The coolant circuit further includes a hose connected to the exhaust port of the relief valve and extending downwards to the vehicle. In-vehicle air conditioner.

3. An in-vehicle air conditioning system according to claim 1 or 2, The coolant circuit further includes a pressure sensor for detecting the pressure in the piping of the coolant circuit, and solenoid valves located outside the vehicle compartment in the upstream and downstream coolant circuits of the cooler core, The aforementioned in-vehicle air conditioning system further comprises a controller, The controller controls the two solenoid valves to a closed state when the value detected by the pressure sensor exceeds a predetermined value, and maintains the two solenoid valves in an open state otherwise. In-vehicle air conditioner.

4. An in-vehicle air conditioning system according to claim 3, When the controller controls the two solenoid valves to be in a closed state, if the pressure in the coolant circuit on the cooler core side rises above the pressure of the two solenoid valves, at least one of the two solenoid valves functions as a relief valve and opens. In-vehicle air conditioner.

5. An in-vehicle air conditioning system according to claim 1 or 2, The aforementioned hydrocarbon refrigerant is propane or a refrigerant mainly composed of propane. In-vehicle air conditioner.

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