Vehicle-mounted air conditioning device

Abstract

The invention provides a vehicle-mounted air conditioning device. This air conditioner is provided with a refrigerant circuit (R), a coolant circuit (C2), and an air-conditioning unit (70). The refrigerant circuit has a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator (26a) for heat absorption, and circulates a hydrocarbon refrigerant. The heat exchanger (40) is integrally formed with the evaporator of the refrigerant circuit, and cools the coolant by means of the refrigerant located in the evaporator. The coolant circuit circulates the coolant and supplies the coolant to the cooler core (72). The air-conditioning unit has an air passage (75) in which a cooler core (72) is disposed, and the air passing through the air passage is cooled by the cooler core and blown into the vehicle interior. The cooling liquid loop (C2) comprises a gas-liquid separator (100) and an overflow valve (102). The relief valve is disposed above the gas-liquid separator on the outside of the vehicle cabin, and opens when the pressure in the gas-liquid separator increases.

Description

Technical Field

[0001] This specification relates to vehicle air conditioning systems, and in particular, discloses vehicle air conditioning systems using hydrocarbon refrigerants. Background Technology

[0002] In recent years, hydrocarbon-based refrigerants such as propane (HC-based refrigerants), which have low global warming coefficients, have been studied as refrigerants for air conditioning systems. Since HC-based refrigerants are flammable, structures for preventing refrigerant leaks and ensuring safety during leaks have been investigated.

[0003] Patent Document 1 discloses the use of propane as a refrigerant for a vehicle air conditioning system. The air conditioning system in this document is configured such that the refrigeration circuit is located in the engine compartment, the engine compartment is separated from the passenger compartment by a partition wall, and the cooling capacity of the refrigeration circuit is transferred to the passenger compartment by a heat pipe passing through the partition wall. Even if the refrigerant leaks from the refrigeration circuit, the refrigerant will not flow into the passenger compartment.

[0004] Existing technical documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-62683 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In a vehicle air conditioning system, consider the following structure: in addition to the refrigerant circuit for hydrocarbon refrigerants, a coolant circuit is provided for circulating the coolant cooled by the refrigerant circuit, and the coolant in the coolant circuit is used to cool the air blown into the vehicle interior.

[0008] Specifically, the system includes a refrigerant circuit that circulates hydrocarbon-based refrigerant, comprising a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption. Furthermore, a heat exchanger is integrally formed with the evaporator of the refrigerant circuit, and the refrigerant located in the evaporator cools the coolant. Additionally, a coolant circuit is provided to circulate the coolant and supply it to a cooler core, which then cools the air blown into the vehicle interior. With this structure, a refrigerant circuit for hydrocarbon-based refrigerant is not located in the path of the air blown into the vehicle interior, thus reducing the risk of hydrocarbon-based refrigerant leakage into the vehicle interior.

[0009] Here, the aforementioned heat exchanger facilitates heat exchange between the hydrocarbon-based refrigerant and the coolant. If this heat exchanger fails due to deterioration or other reasons, the hydrocarbon-based refrigerant may flow into the coolant circuit. A desired structure is one that, even in the event of hydrocarbon-based refrigerant flowing into the coolant circuit, allows the refrigerant to be released from the coolant circuit outside the vehicle compartment, thereby reducing the risk of hydrocarbon-based refrigerant leakage into the vehicle interior.

[0010] This specification discloses an onboard air conditioning device capable of releasing hydrocarbon refrigerant flowing into the coolant circuit from the coolant circuit outside the vehicle compartment.

[0011] Methods for solving problems

[0012] The vehicle air conditioning device disclosed in this specification is characterized by comprising: a refrigerant circuit having a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption, for circulating hydrocarbon refrigerant; a heat exchanger integrally formed with the evaporator of the refrigerant circuit, for cooling coolant using the refrigerant located in the evaporator; a coolant circuit having a cooler core for circulating coolant; and an air conditioning unit having an air passage in which the cooler core is disposed internally, for cooling air passing through the air passage and supplying air into the vehicle interior using the cooler core, wherein the coolant circuit includes a gas-liquid separator and an overflow valve, the overflow valve being disposed on the upper part of the gas-liquid separator outside the vehicle interior, and opening when the pressure in the gas-liquid separator rises.

[0013] According to this structure, when hydrocarbon refrigerant flows into the coolant circuit, the gaseous hydrocarbon refrigerant is captured by the gas-liquid separator, and the pressure inside the gas-liquid separator rises. Consequently, the overflow valve opens, allowing the hydrocarbon refrigerant inside the gas-liquid separator to be released from the coolant circuit outside the vehicle compartment.

[0014] In the vehicle air conditioning device disclosed herein, the coolant circuit may also include a hose connected to the vent of the overflow valve and extending below the vehicle.

[0015] According to this structure, when the overflow valve is opened, the hydrocarbon refrigerant can be guided through the hose to the lower part of the vehicle.

[0016] In the vehicle air conditioning device disclosed herein, the coolant circuit may also include: a pressure sensor for detecting the pressure in the piping of the coolant circuit; and solenoid valves respectively disposed on the coolant circuit upstream and downstream of the coolant core on the outside of the vehicle compartment. The vehicle air conditioning device also includes a controller that controls the two solenoid valves to a closed state when the detected value of the pressure sensor becomes higher than a predetermined value, and otherwise keeps the two solenoid valves in an open state.

[0017] According to this structure, when hydrocarbon refrigerant flows into the coolant circuit, the pressure in the coolant circuit piping increases, causing the two solenoid valves to be closed. Therefore, it is possible to suppress the portion of hydrocarbon refrigerant flowing into the coolant circuit located on the passenger compartment side.

[0018] In the vehicle air conditioning device disclosed herein, it is also possible that when the two solenoid valves are controlled to be closed by the controller, when the pressure in the coolant circuit on the cooler core side of the two solenoid valves rises, at least one of the two solenoid valves functions as an overflow valve and opens.

[0019] According to this structure, when the two solenoid valves are controlled to be closed and the pressure in the coolant circuit on the cooler core side increases due to the vaporization of the coolant, at least one of the two solenoid valves will open, thus preventing damage to the piping of the coolant circuit on the cooler core side.

[0020] In the vehicle air conditioning device disclosed herein, the hydrocarbon refrigerant may be propane or a refrigerant with propane as its main component.

[0021] The vehicle disclosed in this manual is equipped with the aforementioned vehicle air conditioning system.

[0022] Invention Effects

[0023] According to the technology disclosed in this specification, hydrocarbon refrigerant flowing into the coolant circuit can be released from the coolant circuit outside the vehicle compartment. Attached Figure Description

[0024] Figure 1 This is a schematic diagram showing the structure of an air conditioning unit.

[0025] Figure 2 This is a schematic diagram showing the configuration of the air conditioning system inside the vehicle.

[0026] Figure 3 This is a diagram showing the structure of the second coolant circuit.

[0027] Figure 4 This is a diagram showing the state of hydrocarbon refrigerant flowing into the second coolant circuit.

[0028] Figure 5 This diagram shows the state of coolant leaking from the second coolant circuit.

[0029] Figure 6 This is a diagram showing the structure of another second coolant circuit.

[0030] Figure 7 This is a schematic diagram showing the structure of another air conditioning unit. Detailed Implementation

[0031] <Pre-position>

[0032] The embodiments will now be described with reference to the accompanying drawings. In all the drawings, identical reference numerals are used to denote equivalent elements, and repeated descriptions are omitted. In the following description, unless otherwise specified, terms indicating direction and orientation, such as front, back, left, right, up, and down, refer to directions and orientations related to the vehicle. Figure 2 In the diagram, the direction of arrow FR indicates forward, and the direction of arrow UP indicates upward.

[0033] Air conditioning units are installed in vehicles such as automobiles. In the embodiments described below, the type of vehicle equipped with the air conditioning unit is not limited. For example, the vehicle can be an engine-powered automobile or an electric vehicle powered by a motor. Alternatively, the vehicle can be a hybrid electric vehicle or a plug-in hybrid electric vehicle equipped with both an engine and a motor. Furthermore, the vehicle can be a fuel cell vehicle equipped with a fuel cell or a battery electric vehicle that uses electricity stored in a battery for propulsion.

[0034] Air conditioning units have a refrigerant circuit for circulating hydrocarbon-based refrigerants (referred to as HC-based refrigerants). HC-based refrigerants are flammable. Examples of HC-based refrigerants include propane, butane, isobutane, ethane, ethylene, and propylene. In the refrigerant circuit, one of these HC-based refrigerants or a mixture of two or more of them can be used. Alternatively, a mixture of refrigerants, primarily composed of one or more HC-based refrigerants and including refrigerants other than HC-based refrigerants and various additives, can also be used in the refrigerant circuit. For example, propane or a refrigerant primarily composed of propane and including at least one of other refrigerants and additives (a propane-based refrigerant) can be used in the refrigerant circuit. As an example, an HC-based refrigerant can also be R 290. In this specification, hydrocarbon-based refrigerant (HC-based refrigerant) refers to a pure hydrocarbon-based refrigerant or a refrigerant primarily composed of a hydrocarbon-based refrigerant.

[0035] The refrigerant circuit serves as the heat source for the air conditioning unit. Along the refrigerant flow direction, the refrigerant circuit sequentially includes a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption. A receiver can also be installed between the condenser and the expansion valve. Alternatively, an accumulator can be installed between the evaporator and the compressor.

[0036] An air conditioning unit may include: a high-temperature coolant circuit, which circulates coolant heated by the condenser of the refrigerant circuit; and a low-temperature coolant circuit, which circulates coolant cooled by the evaporator of the refrigerant circuit. The coolant is the heat medium, and the high-temperature and low-temperature coolant circuits are respectively heat medium circuits.

[0037] In the implementation described below, such as Figure 1 As shown, the air conditioning unit 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. Furthermore, the air conditioning unit 12 can be configured without the third coolant circuit C3; this is explained below. Figure 7 Please provide an explanation.

[0038] The coolant in the first to third coolant circuits C1, C2, and C3 can be cooling water. That is, the coolant can be: water without additives; water mixed with additives such as antifreeze and corrosion inhibitors; or coolant, etc. Alternatively, the coolant can also be a liquid heat medium such as oil; there are no restrictions.

[0039] In the embodiments described below, the refrigerant circuit is located under the vehicle's hood (front engine hood). Hereinafter, regardless of the presence or type of power source (engine, motor, etc.) under the hood, the area under the hood will be referred to as the "engine compartment".

[0040] <Implementation Method>

[0041] Figure 1 This is a schematic diagram showing the structure of the air conditioning device 12 according to the embodiment. Figure 2 This is a schematic diagram showing the configuration of the air conditioning unit 12 inside the vehicle. The vehicle 10 is equipped with a battery 54 that supplies electricity to the motor, which serves 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.

[0042] The air conditioning unit 12 regulates the air inside the vehicle compartment 90 and cools the battery 54. In addition, the air conditioning unit 12 may also be a structure that cools the battery 54 and on-board equipment such as the PCU (Power Control Unit), or replaces the battery 54 to cool the on-board equipment such as the PCU.

[0043] like Figure 1 As shown, the air conditioning unit 12 includes a refrigerant circuit R as a heat source, first to third coolant circuits C1, C2, and C3, and an air conditioning unit 70. The first coolant, heated by the refrigerant in the refrigerant circuit R, circulates in the first coolant circuit C1. The second coolant, cooled by the refrigerant in the refrigerant circuit R, circulates in the second coolant circuit C2. Similarly, the third coolant, cooled by the refrigerant in the refrigerant circuit R, circulates in the third coolant circuit C3. The air conditioning unit 70 supplies air cooled by the second coolant circulating in the second coolant circuit C2 to the vehicle interior.

[0044] The refrigerant circuit R is a closed loop that circulates HC-type refrigerant (hereinafter referred to as refrigerant) by connecting the compressor 20, condenser 22, storage tank 28, expansion valves 24a and 24b, and evaporators 26a and 26b in sequence through refrigerant piping. Expansion valve 24a is connected in series with evaporator 26a, and similarly, expansion valve 24b is connected in series with evaporator 26b. The refrigerant flow paths of expansion valve 24a and evaporator 26a are connected in parallel with the refrigerant flow paths of expansion valve 24b and evaporator 26b.

[0045] The air conditioning unit 12 includes a heat exchanger 30. The heat exchanger 30 is integrally formed with the condenser 22 of the refrigerant circuit R, enabling heat exchange between the refrigerant in the refrigerant circuit R and the first coolant in the first coolant circuit C1. The heat exchanger 30 is a water-cooled condenser, for example, a plate heat exchanger. The heat exchanger 30 is the first heat exchanger.

[0046] The first coolant circuit C1 is a closed loop that circulates the first coolant by connecting the water pump 32, heat exchanger 30, and radiator 34 sequentially through coolant piping. The radiator 34 is a heat exchanger that allows the first coolant to exchange heat with the vehicle's running airflow (Wtr). In the first coolant circuit C1, the first coolant, pressurized by the water pump 32, becomes high-temperature during its passage through the heat exchanger 30 due to heat dissipation from the refrigerant in the condenser 22 of the refrigerant circuit R. The high-temperature first coolant is then transported to the radiator 34, where it is cooled by the vehicle's running airflow (Wtr).

[0047] Additionally, the air conditioning unit 12 includes a heat exchanger 40. The heat exchanger 40 is integrally formed with the evaporator 26a of the refrigerant circuit R, allowing heat exchange between the refrigerant in the refrigerant circuit R and the second coolant in the second coolant circuit C2. The heat exchanger 40 can be, for example, a plate heat exchanger. The heat exchanger 40 is a second heat exchanger.

[0048] The second coolant circuit C2 is a closed loop that circulates the second coolant, consisting of a water pump 42, a heat exchanger 40, and a cooler core 72 connected sequentially by coolant piping. The cooler core 72 is a heat exchanger located in the air passage 75 of the air conditioning unit 70, facilitating heat exchange between the second coolant and the air conditioning airflow Wac. In the second coolant circuit C2, the second coolant, pumped by the water pump 42, becomes cold due to the heat absorption of the refrigerant in the evaporator 26a of the refrigerant circuit R during its passage through the heat exchanger 40. This cold second coolant is then sent to the cooler core 72, where it cools the air conditioning airflow Wac.

[0049] Additionally, the air conditioning unit 12 includes a heat exchanger 50. The heat exchanger 50 is integrally formed with the evaporator 26b of the refrigerant circuit R, enabling heat exchange between the refrigerant in the refrigerant circuit R and the third coolant in the third coolant circuit C3. The heat exchanger 50 can be, for example, a plate heat exchanger. The heat exchanger 50 is a third heat exchanger.

[0050] The third coolant circuit C3 is a closed loop that circulates the third coolant, formed by connecting the water pump 52, heat exchanger 50, and battery 54 sequentially via coolant piping. In the third coolant circuit C3, the coolant pumped by the water pump 52 becomes cold as it passes through the heat exchanger 50 due to the heat absorption of the refrigerant in the evaporator 26b of the refrigerant circuit R. This cooled third coolant is then delivered 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.

[0051] In this specification, expansion valve 24a, evaporator 26a, and heat exchanger 40 are referred to as air conditioning expansion valve, air conditioning evaporator, and air conditioning heat exchanger, respectively. Furthermore, expansion valve 24b, evaporator 26b, and heat exchanger 50 are referred to as battery expansion valve, battery evaporator, and battery heat exchanger, respectively.

[0052] In the refrigerant circuit R, the refrigerant circulates as follows: Compressor 20 discharges high-pressure gaseous refrigerant, which dissipates heat and condenses in the condenser 22 by exchanging heat with the first coolant in the first coolant circuit C1 of the heat exchanger 30, becoming a 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 reservoir 28, becoming a low-pressure refrigerant, and flows into the evaporator 26a. The low-pressure refrigerant flowing into the evaporator 26a exchanges heat with the second coolant in the second coolant circuit C2 of the heat exchanger 40, evaporating into a gaseous refrigerant, and flows out of the evaporator 26a, returning to the compressor 20.

[0053] Furthermore, the high-pressure liquid refrigerant flowing out of the condenser 22 is depressurized and expanded by the expansion valve 24b via the storage tank 28, becoming a low-pressure refrigerant, and flows into the evaporator 26b. The low-pressure refrigerant flowing into the evaporator 26b exchanges heat with the third coolant in the third coolant circuit C3 of the heat exchanger 50, evaporates, becomes a gaseous refrigerant, and flows out of the evaporator 26b, returning to the compressor 20.

[0054] The air conditioning unit 70 includes a blower 80 and an air passage 75 formed by a housing (not shown). Inside the air passage 75, the blower 80, a cooler core 72, and a heater core 74 are arranged sequentially in the airflow direction. The heater core 74 is, for example, a heat exchanger that supplies engine coolant or coolant heated by a PTC heater for water heating. Alternatively, the heater core 74 may be a structure that supplies coolant heated by the heat exchanger 30.

[0055] Blower 80 introduces air into air passage 75 through an intake port (not shown), ventilating the cooler core 72 and heater core 74, thereby blowing temperature-controlled air into the vehicle interior. An air mixing gate 82 is provided inside air passage 75, adjusting the ratio of air flowing from cooler core 72 to heater core 74. Furthermore, air conditioning unit 70 can employ conventional HVAC (Heating, Ventilation, and Air Conditioning) technology.

[0056] like Figure 2 As shown, the engine compartment 92 and the passenger compartment 90 are separated by a dashboard 94. An instrument panel (not shown) is located on the passenger compartment 90 side of the dashboard 94. An air conditioning unit 70 is positioned between the instrument panel and the dashboard 94.

[0057] The battery 54 is located under the floor of the passenger compartment 90, specifically under the floor panel 96. Alternatively, the battery 54 can also be located under the seats, at the rear of the vehicle, or in any other location.

[0058] The air conditioning unit 12 is equipped with a controller. This controller can be connected to [the system described later]. Figure 6 The controller 110 shown may be the same as, or may be different from, the controller. The controller may be configured to include a processor and a storage device, 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 external temperature, internal temperature, battery temperature, solar radiation sensors, pressure sensors, etc.) and setting information from the user-operated control panel. Alternatively, the controller may employ existing air conditioning unit control technology.

[0059] like Figure 2 As shown, the refrigerant circuit R is located within the engine compartment 92. The first coolant circuit C1 is located in front of the refrigerant circuit R. The refrigerant circuit R can be positioned further back than the frontal collision deformation zone of the vehicle. Therefore, in the event of a frontal collision with the vehicle 10, the collision load input to the refrigerant circuit R can be reduced.

[0060] Figure 3 The structure of the second coolant circuit C2 is shown in more detail. Figure 3 And the following explanation Figures 4-6 In the diagram, the thick arrow on the outer periphery of the second coolant circuit C2 (or C2a) indicates the flow direction of the second coolant. Hereinafter, the second coolant circuit C2 and the second coolant will be referred to as coolant circuit C2 and coolant, respectively.

[0061] like Figure 3 As shown, the coolant circuit C2 includes a gas-liquid separator 100 and an overflow valve 102. The gas-liquid separator 100 is a hollow, box-shaped portion formed 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 volume exists in the upper part of the gas-liquid separator 100. The gas-liquid separator 100 is located outside the vehicle compartment 90, i.e., inside the engine compartment 92.

[0062] The overflow valve 102 is located on the upper part of the gas-liquid separator 100. The overflow valve 102 opens when the pressure in the gas-liquid separator 100 rises. The overflow valve 102 is located on the outside of the vehicle compartment 90, i.e., inside the engine compartment 92.

[0063] The coolant circuit C2 includes a hose 104. The hose 104 connects to the vent of the overflow valve 102 and extends below the vehicle body. The hose 104 is located within the engine compartment 92. The hose 104 is positioned separately from heat-generating components such as the engine, motor, and converter. The tip 105 of the hose 104 is located at the bottom of the vehicle body. The tip 105 of the hose 104 may also be fixed to a body structure located in the lower part (or bottom) of the engine compartment 92.

[0064] The heat exchanger 40 includes a primary side section 40-1 and a secondary side section 40-2. The primary side section 40-1 is an evaporator 26a, which supplies HC-based refrigerant. The secondary side section 40-2 supplies coolant. 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 section 40-1 of the heat exchanger 40 is higher than the internal pressure of the secondary side section 40-2.

[0065] Next, the effects of the above-described implementation methods will be explained.

[0066] exist Figure 4The diagram illustrates a situation where a damaged section 200 forms in the partition wall between the primary side portion 40-1 and the secondary side portion 40-2 of the heat exchanger 40 due to deterioration or other factors. In this case, the HC-based refrigerant in the primary side portion 40-1 flows into the secondary side portion 40-2. The HC-based refrigerant flows into the secondary side portion 40-2 in gaseous form, or it becomes sludge after flowing into the secondary side portion 40-2. Furthermore, the HC-based refrigerant flows within the coolant circuit C2 as coolant mixed with the coolant in the coolant circuit C2.

[0067] At this time, as Figure 4 As shown, HC-based refrigerant is captured by the gas-liquid separator 100. The pressure in the gas-liquid separator 100 increases as the HC-based refrigerant is captured. Consequently, the overflow valve 102 opens, allowing the HC-based refrigerant in the gas-liquid separator 100 to be released through the hose 104 to the coolant circuit C2. HC-based refrigerant is generally heavier than air, so it flows downwards in the hose 104. Therefore, the HC-based refrigerant can be released to a relatively safe location under the vehicle body.

[0068] Figure 5 This indicates a leak of coolant from the coolant circuit C2. The figure shows a damage section 200 in the heat exchanger 40 and damage sections 202 and 204 in the piping of the coolant circuit C2 and the cooler core 72, respectively. Figure 5 As shown, even in the event of simultaneous damage to the heat exchanger 40 and the coolant circuit C2, 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.

[0069] Furthermore, according to the above-described embodiment, when the internal pressure of the coolant circuit C2 rises due to the inflow of HC-based refrigerant into the coolant circuit C2, the overflow valve 102 opens, thereby suppressing the pipe damage to the coolant circuit C2 caused by the pressure rise.

[0070] Furthermore, the structure of the gas-liquid separator 100, overflow valve 102, and hose 104 described above can also be applied to the first coolant circuit C1 or the third coolant circuit C3.

[0071] <Another coolant circuit>

[0072] Next, the other coolant circuit will be explained. Figure 6 The construction of another second coolant circuit C2a is shown. This coolant circuit C2a is relative to the coolant circuit C2 described above (see reference). Figure 3A pressure sensor 112 and two solenoid valves 114 and 115 were added. The pressure sensor 112 detects the pressure in the piping of the coolant circuit C2. The two solenoid valves 114 and 115 are respectively installed on the upstream and downstream sides of the cooler core 72 on the outside of the vehicle compartment 90 (inside the engine compartment 92).

[0073] The air conditioning unit 12 includes a controller 110. The controller 110 is configured to include a processor and a storage device. The detection signal s_P from the pressure sensor 112 is input to the controller 110. In addition, the controller 110 outputs control signals s_B1 and s_B2 from the solenoid valves 114 and 115.

[0074] When the pressure sensor 112 detects a signal s_P indicating 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, the controller 110 closes both solenoid valves 114 and 115. Otherwise, the controller 110 keeps both 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 are closed, thus preventing HC-based refrigerant from flowing out towards the cooler core 72.

[0075] Furthermore, at least one of the two solenoid valves 114 and 115 can also be configured such that, when both solenoid valves 114 and 115 are closed by the controller 110, the valve opens when the internal pressure of the piping on the cooler core 72 side rises (i.e., it functions as an overflow valve). Thus, when the internal pressure of the piping on the cooler core 72 side rises due to coolant vaporization, etc., damage to the piping on the cooler core 72 side can be prevented.

[0076] The structure of the pressure sensor 112, the two solenoid valves 114 and 115, and the controller 110 described above can also 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 can also be located in the battery 54 (see reference). Figure 1 Piping on the upstream and downstream sides of the ).

[0077] <Another air conditioning unit>

[0078] Next, another air conditioning unit will be described. Figure 7 This is a schematic diagram showing the structure of another air conditioning unit 12a. This air conditioning unit 12a is derived from the aforementioned air conditioning unit 12 (see reference 12). Figure 1The structure of expansion valve 24b, third heat exchanger 50, and third coolant circuit C3 is omitted in the original text. The refrigerant circuit Ra of the air conditioning unit 12a is formed by connecting the compressor 20, condenser 22, storage tank 28, expansion valve 24a, and evaporator 26a in sequence through refrigerant piping.

[0079] The air conditioning unit 12a does not cool the battery 54 (see reference). Figure 1 The structure is as follows. The battery 54 can be cooled by a cooling device separately from the air conditioning unit 12a. Furthermore, vehicles such as engine vehicles that do not have a battery 54 (a battery that supplies power to the motor) do not require a battery cooling device, and therefore the air conditioning unit 12a can be used. The aforementioned coolant circuits C2 and C2a can also be applied to the air conditioning unit 12a. Figures 3-6 The structure of ).

[0080] Explanation of reference numerals in the attached figures

[0081] 10 Vehicle; 12, 12a Air conditioning unit; 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 Storage tank; 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 mixing door; 90 Cabin; 92 Engine compartment; 94 Partition; 96 Floor panel; 100 Gas-liquid separator; 102 Overflow valve; 104 Hose; 105 Front end; 110 Controller; 112 Pressure sensor; 114, 115 Solenoid valves; 200, 202, 204 Damaged parts; R, Ra Refrigerant circuit; C1 First coolant circuit; C2, C2a Second coolant circuit (coolant circuit); C3 Third coolant circuit (battery coolant circuit); Wtr Driving air; Wac Air conditioning air.

Claims

1. A vehicle-mounted air conditioning device, comprising: The refrigerant circuit includes a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption, for circulating hydrocarbon refrigerants. A heat exchanger, integrally formed with the evaporator of the refrigerant circuit, uses the refrigerant located in the evaporator to cool the coolant; The coolant circuit has a cooler core for circulating the coolant. as well as An air conditioning unit has an air passage in which the cooler core is internally disposed, and uses the cooler core to cool the air passing through the air passage and deliver it into the vehicle interior. The coolant circuit includes a gas-liquid separator and an overflow valve. The overflow valve is located on the outside of the vehicle compartment, above the gas-liquid separator, and opens when the pressure in the gas-liquid separator rises.

2. The vehicle air conditioning device according to claim 1, The coolant circuit also includes a hose connected to the vent of the overflow valve and extending under the vehicle.

3. The vehicle air conditioning device according to claim 1 or 2, The coolant circuit also includes: A pressure sensor detects the pressure within the piping of the coolant circuit; and a solenoid valve, Each coolant circuit in the coolant circuit located on the upstream and downstream sides of the cooler core outside the vehicle compartment, The vehicle air conditioning unit also includes a controller. When the pressure sensor detects a value higher than a predetermined value, the controller closes both solenoid valves; otherwise, it keeps both solenoid valves open.

4. The vehicle air conditioning device according to claim 3, When the two solenoid valves are controlled to be closed by the controller, at least one of the two solenoid valves will open as an overflow valve when the pressure in the coolant circuit on the cooler core side of the two solenoid valves rises.

5. The vehicle air conditioning device according to claim 1 or 2, The hydrocarbon refrigerant is propane or a refrigerant with propane as its main component.

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