Vehicle air conditioning device

Abstract

[Problem] Refrigerants having a low environmental impact are attracting attention due to environmental considerations. However, since some such substances are flammable, there are safety issues when used as a refrigerant for vehicles. [Solution] This vehicle air conditioning device has a refrigerant circuit in which a flammable refrigerant that is heavier than air circulates, and is provided with a refrigerant unit in which a compressor, a condenser, an evaporator, and an accumulator that constitute the refrigerant circuit are integrated, the vehicle air conditioning device being provided with: a bottomed unit cover that is formed to have a volume equal to or greater than a predetermined volume and that surrounds the side surfaces of the refrigerant unit; and piping that connects the bottom surface of the unit cover to the outside of a vehicle driving compartment. In addition, a guide portion for guiding leaked refrigerant to the piping is formed in the unit cover.

Description

Vehicle air conditioner

[0001] The present invention relates to a vehicle air conditioner.

[0002] Vehicle interior air conditioning uses a refrigerant whose temperature is increased and decreased by compression and expansion to adjust the temperature inside the vehicle. As a refrigerant used for vehicle interior air conditioning, a refrigerant with a low environmental load has been attracting attention. For example, R32 and propane are known as substances with a very low global warming potential (GWP) and high energy efficiency (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2024-122202

[0004] However, refrigerants usually leak over time. As shown in FIG. 3, in a vehicle equipped with a conventional vehicle air conditioner 2, when propane or the like, which is heavier than air, is used as a refrigerant, the leaked refrigerant A is likely to accumulate on the under cover 40 located vertically below after leaking from the refrigerant unit R, and there is a risk of ignition of the leaked refrigerant A when a spark occurs from surrounding electrical components.

[0005] Therefore, there is a dangerous aspect in using a flammable substance such as propane as a refrigerant for a vehicle air conditioner, and there are safety problems.

[0006] The present invention has been made to solve such conventional technical problems, and an object thereof is to provide a vehicle air conditioner that can safely use a flammable refrigerant.

[0007] In order to solve such problems, a vehicle air conditioner according to the present invention has the following configuration.

[0008] In a vehicle air conditioner having a refrigerant circuit in which a flammable refrigerant heavier than air circulates and including a refrigerant unit in which a compressor, a condenser, an evaporator, and an accumulator constituting the refrigerant circuit are integrated, the vehicle air conditioner includes a bottomed unit cover that surrounds a side surface of the refrigerant unit formed so that the volume is equal to or greater than a predetermined volume, and a pipe that connects the bottom surface of the unit cover and the outside of the vehicle driving chamber, and an induction part for guiding the leaked refrigerant to the pipe is formed in the unit cover. A vehicle air conditioner characterized by this.

[0009] According to the present invention, which has these features, it is possible to provide a vehicle air conditioning system that can safely utilize flammable refrigerants.

[0010] This is a diagram showing the configuration of a leaked refrigerant discharge device according to the first embodiment of the present invention. This is a diagram showing the configuration of a leaked refrigerant discharge device according to the second embodiment of the present invention. This is a diagram showing the distribution of leaked refrigerant in a conventional vehicle.

[0011] Embodiments of the present invention will be described below with reference to the drawings. Each drawing is illustrative of an embodiment of the present invention and is not intended to limit the invention. In the following description, the same reference numerals in different figures indicate parts with the same function, and redundant explanations in each figure will be omitted as appropriate.

[0012] Furthermore, the dimensional relationships of each element in the drawings are for the purpose of facilitating understanding and are not intended to restrict the actual dimensional ratios.

[0013] Figure 1 shows the configuration of a vehicle air conditioning system 1 according to an embodiment of the present invention. The vehicle air conditioning system 1 comprises a refrigerant unit R which serves as a heat source and integrates the components of the refrigerant circuit into a single unit, a heat transfer medium circuit 3 which circulates a heat transfer medium whose temperature is controlled by heat exchange with the refrigerant, and an air conditioning unit (HVAC) 20 which supplies air whose temperature has been controlled by the heat transfer medium circulating in the heat transfer medium circuit 3 into the vehicle interior.

[0014] In the example shown in Figure 1, the refrigerant unit R is configured by sequentially connecting a compressor 10, a condenser 12, an expansion valve 14, an evaporator 16, and an accumulator 18 with refrigerant piping 32, thereby forming a refrigerant circuit. The refrigerant circuit is a closed circuit through which the refrigerant circulates. Alternatively, the refrigerant unit R may also have a circuit that includes, for example, a receiver tank downstream of the condenser 12.

[0015] The heat transfer medium circuit 3 is a circuit that circulates the heat transfer medium, and is composed of an air conditioning unit 20, a low-temperature heat exchanger 26, a high-temperature heat exchanger 28, and a radiator 30, which are connected by heat transfer medium piping 34.

[0016] The heat transfer medium circuit 3 receives the high-temperature and low-temperature heat generated by the refrigerant unit R via a heat transfer medium in the high-temperature heat exchanger 28 and low-temperature heat exchanger 26 provided in the heat transfer medium circuit 3, and transports it to the air conditioning unit 20. The detailed flow path of the heat transfer medium circuit 3 is not shown, but the heat transfer medium circuit 3 is provided with multiple three-way valves, four-way valves, etc. (not shown) for switching the flow of the heat transfer medium, and the path through which the heat transfer medium flows is configured to be switched according to the type of heating and cooling function desired by the passenger.

[0017] The air conditioning unit 20 includes a first heat exchanger 22 and a second heat exchanger 24. The air conditioning unit 20 draws in air (outside or inside) and passes it through the first heat exchanger 22 or the second heat exchanger 24 to perform heat exchange between the air and the heat transfer medium. In this way, it adjusts the air to the target temperature set by the passengers and blows it into the room.

[0018] The vehicle air conditioning system 1 is typically located at the front upper part of the vehicle, as illustrated in Figure 1. The air conditioning unit 20 that constitutes the vehicle air conditioning system 1 is often located in the center of the vehicle, in front of the driver's seat and the passenger seat. A firewall 46 is provided between the refrigerant unit R located outside the vehicle and the air conditioning unit 20 located inside the vehicle, serving as a partition between the vehicle's drive compartment and the passenger compartment.

[0019] An under cover 40 is provided at the front lower part of the vehicle. The under cover 40 is provided with a gap hole 44, and a drain pipe 42 is positioned so as to pass from the air conditioning unit 20 through the gap hole 44 in the under cover 40 to the outside of the vehicle's drive compartment. For example, condensed water generated in the first heat exchanger 22 when heat is exchanged between the heat transfer medium and air is discharged from under the vehicle floor to the outside of the vehicle's drive compartment through the drain pipe 42.

[0020] (First Embodiment) In the first embodiment of the present invention, a unit cover 50 is provided below the refrigerant unit R. Since flammable refrigerants such as propane are heavier than air, if they leak, the leaked refrigerant A will move vertically downward. Electrical components are usually located below the refrigerant unit R, so if the leaked gaseous refrigerant comes into contact with the electrical components, there is a risk of ignition.

[0021] The unit cover 50 is a box-shaped container with a bottom and an open top for temporarily receiving leaked refrigerant A leaking from the refrigerant unit R, and is formed to cover the bottom and lower sides of the refrigerant unit R. By positioning it lower and close to the refrigerant unit R, it prevents the leaked refrigerant A from moving vertically downward and coming into contact with electrical components.

[0022] The volume of the formed unit cover 50 is at least a predetermined volume that can temporarily contain leaked refrigerant A that has leaked over time, and that prevents the leaked refrigerant A from overflowing from the unit cover 50. Preferably, even in the case of a sudden leak of refrigerant, the volume is at least a predetermined volume that can temporarily contain it and that prevents the leaked refrigerant A from overflowing from the unit cover 50.

[0023] A gas exhaust pipe 52 is installed from the unit cover 50 to the underside of the vehicle floor. The material of the gas exhaust pipe 52 can be any material that prevents refrigerant leakage, and can be either a hard or soft material. The gas exhaust pipe 52 is a pipe with both ends open; one end is connected to the bottom surface of the unit cover 50, and the other end is extended to the underside of the under cover 40. Leaked refrigerant A, temporarily received by the unit cover 50, is discharged outside the vehicle's drive chamber via the gas exhaust pipe 52. By using the gas exhaust pipe 52, it is possible to prevent contact between electrical components located below the refrigerant unit R and the leaked refrigerant A, thus ensuring safety even when using a flammable refrigerant. Furthermore, the bottom surface of the unit cover 50 is formed such that the part where the gas exhaust pipe 52 is connected is the lowest point, for example, by being generally concave. The bottom surface of the unit cover 50, which has this shape, functions as a guide section that directs the leaked refrigerant A to the gas discharge pipe 52, allowing the leaked refrigerant A temporarily received by the unit cover 50 to be guided to the gas discharge pipe 52 and discharged naturally. The form of the guide section that directs the leaked refrigerant A to the gas discharge pipe 52 may be a form in which a slope is provided on the bottom surface, or a form in which a groove is provided.

[0024] Furthermore, by running the gas exhaust pipe 52 and the drain pipe 42 side-by-side from a certain point, and passing both the gas exhaust pipe and the drain pipe through the same gap 44 provided in the under cover 40 for the drain pipe 42, it becomes unnecessary to create a new gap 40 for the gas exhaust pipe 52, which is economical.

[0025] (Second Embodiment) Figure 2 shows only the essential parts of a second embodiment of the present invention. The other configurations are basically the same as those shown in Figure 1. In the first embodiment, the gas discharge pipe 52 connected to the unit cover 50 led directly to the outside of the vehicle drive chamber, but in the second embodiment, a junction 60 is provided where it merges with the drain pipe 42, and thereafter it is led to the outside of the vehicle drive chamber via a common discharge pipe 54 through a gap hole 44 provided in the under cover 40. By adopting this configuration, it is possible to reduce the number of pipes inside the vehicle drive chamber.

[0026] Furthermore, as shown in Figure 2, by providing a check valve 56 near the junction 60 of the drain pipe 42 with the gas discharge pipe 52 as a backflow prevention device for the upstream side of the drain pipe 42, it is possible to prevent leaked refrigerant A from flowing back into the vehicle interior. Alternatively, a Y-shaped pipe may be used instead of the check valve 56 to prevent backflow.

[0027] As described above, by using the present invention, it is possible to reliably discharge the leaked refrigerant A leaking from the refrigerant unit R to the outside of the vehicle's drive chamber, thereby improving safety when a flammable gas is used as the refrigerant.

[0028] Furthermore, by utilizing the existing drain hole 44 for the drain pipe 42 provided in the under cover 40, the new work process can be simplified. In addition, by using a configuration that shares the existing drain pipe (a configuration that uses a common discharge pipe 54), not only can equipment be saved, but space in the vehicle's drive compartment can also be reduced.

[0029] In the embodiment of the present invention, the gas exhaust pipe 52 is shown to pass through a gap hole 44 provided in the under cover 40, but the gas exhaust pipe 52 may also be routed to a location where there is no under cover 40.

[0030] Furthermore, the present invention is applicable to vehicles that use a refrigerant in their vehicle air conditioning system, whether the vehicle is powered by a battery or an engine.

[0031] Furthermore, any changes to the design, etc., that do not depart from the spirit of the present invention are also included in this invention.

[0032] 1, 2: Vehicle air conditioning system, 3: Heat transfer fluid circuit, 10: Compressor, 12: Condenser, 14: Expansion valve, 16: Evaporator, 18: Accumulator, 20: Air conditioning unit (HVAC), 22: First heat exchanger, 24: Second heat exchanger, 26: Low-temperature heat exchanger, 28: High-temperature heat exchanger, 30: Radiator, 32: Refrigerant piping, 34: Heat transfer fluid piping, 40: Under cover, 42: Drain pipe, 44: Gap hole, 46: Firewall, 50: Unit cover, 52: Gas discharge pipe, 54: Common discharge pipe, 56: Check valve, 60: Junction, A: Leaking refrigerant, R: Refrigerant unit

Claims

1. A vehicle air conditioning system having a refrigerant circuit through which a flammable refrigerant heavier than air circulates, and comprising a refrigerant unit that integrates a compressor, condenser, evaporator, and accumulator constituting the refrigerant circuit, wherein the vehicle air conditioning system comprises a bottomed unit cover surrounding the side surface of the refrigerant unit, formed to have a volume greater than or equal to a predetermined volume, and piping connecting the bottom surface of the unit cover to the outside of the vehicle's drive chamber, and the unit cover is provided with a guide section that guides leaked refrigerant to the piping.

2. The vehicle air conditioning system according to claim 1, characterized in that the piping connected to the unit cover is connected to the outside of the vehicle's drive chamber in conjunction with the drain pipe.

3. The vehicle air conditioning system according to claim 1, characterized in that the piping connected to the unit cover has a junction with a drain pipe.

4. The vehicle air conditioning system according to claim 3, characterized in that it is provided with a backflow prevention section to the upstream side of the drain pipe near the confluence with the drain pipe.

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