Vehicle air conditioning system

Abstract

Due to environmental concerns, refrigerants with low environmental impact are gaining attention. However, some of these substances are flammable, posing safety problems for their use as refrigerants in vehicles. [Solution] A vehicle air conditioning system has a refrigerant circuit through which a flammable refrigerant heavier than air circulates, and a refrigerant unit that integrates a compressor, condenser, evaporator, and accumulator constituting the refrigerant circuit, wherein the vehicle air conditioning system includes a bottomed unit cover that surrounds the sides of the refrigerant unit, formed to have a volume greater than or equal to a predetermined volume, and piping that connects the bottom surface of the unit cover to the outside of the vehicle's drive chamber. Furthermore, the unit cover has a guide section that directs leaked refrigerant to the piping.

Description

Technical Field

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

Background Art

[0002] Vehicle interior air conditioning uses a refrigerant whose temperature is raised and lowered by compression and expansion, etc., to adjust the temperature inside the vehicle. As a refrigerant used for vehicle interior air conditioning, a refrigerant with a low environmental load has come to be noticed. 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).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, refrigerants usually leak over time. As shown in FIG. 3, in a vehicle equipped with a conventional vehicle air conditioner 2, when using propane or the like, which is heavier than air, 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 are risks 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.

Means for Solving the Problems

[0007] To solve these problems, the vehicle air conditioning system according to the present invention has the following configuration.

[0008] A vehicle air conditioning system having a refrigerant circuit through which a flammable refrigerant heavier than air circulates, and comprising a refrigerant unit integrating a compressor, condenser, evaporator, and accumulator constituting the refrigerant circuit, wherein the vehicle air conditioning system comprises a bottomed unit cover surrounding the sides 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 for guiding leaked refrigerant to the piping. [Effects of the Invention]

[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. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram showing the configuration of a leaked refrigerant discharge device according to the first embodiment of the present invention. [Figure 2] This is a diagram showing the configuration of a leaked refrigerant discharge device according to a second embodiment of the present invention. [Figure 3] This diagram shows the distribution of leaked refrigerant in a conventional vehicle. [Modes for carrying out the invention]

[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 include a circuit with, 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 equipped 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 conditioner 1 is usually disposed at the upper front part of the vehicle as illustrated in FIG. 1. The air conditioning unit 20 constituting the vehicle air conditioner 1 is often provided at the central part of the vehicle in front between the driver's seat and the passenger seat. A firewall 46 is provided as a partition wall for partitioning between the vehicle drive chamber and the passenger compartment between the refrigerant unit R provided outdoors and the air conditioning unit 20 provided indoors.

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

[0020] (First Embodiment) In the first embodiment of the present invention, a unit cover 50 is disposed under the refrigerant unit R. Since a combustible refrigerant such as propane is heavier than air, when leaked, the leaked refrigerant A moves vertically downward. Since electrical components are usually arranged below the refrigerant unit R, there is a risk of ignition if the leaked gaseous refrigerant comes into contact with the electrical components.

[0021] The unit cover 50 is a bottomed box-shaped container with an open upper surface for temporarily receiving the leaked refrigerant A leaking from the refrigerant unit R, and is formed so as to cover the bottom surface and the lower side surface of the refrigerant unit R. By disposing it at a position close to the refrigerant unit R below, the leaked refrigerant A is prevented from moving vertically downward and coming into contact with the electrical components.

[0022] The volume of the unit cover 50 formed is at least a predetermined volume that can temporarily receive the leaked refrigerant A that has leaked over time and prevent the leaked refrigerant A from overflowing from the unit cover 50. Preferably, even when the refrigerant leaks suddenly, it is a predetermined volume or more that can temporarily receive the leaked refrigerant A and prevent the leaked refrigerant A from overflowing from the unit cover 50.

[0023] A gas discharge pipe 52 is disposed from the unit cover 50 to under the vehicle floor. The material of the gas discharge pipe 52 may be any material that does not leak refrigerant, and either a hard material or a soft material can be used. The gas discharge 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 drawn out to the lower side of the under cover 40. The leaked refrigerant A temporarily received by the unit cover 50 is discharged outside the vehicle drive chamber through the gas discharge pipe 52. By using the gas discharge pipe 52, it is possible to prevent contact between the electrical components located below the refrigerant unit R and the leaked refrigerant A, so safety can be ensured even when a flammable refrigerant is used. Also, the bottom surface of the unit cover 50 is formed so that the portion connecting the gas discharge pipe 52 of the unit cover 50 is the lowest point, for example, so that it is concave as a whole. The bottom surface of the unit cover 50 having such a shape functions as a guiding portion for guiding the leaked refrigerant A to the gas discharge pipe 52, and can guide the leaked refrigerant A temporarily received by the unit cover 50 to the gas discharge pipe 52 and discharge it naturally. The form of the guiding portion for guiding the leaked refrigerant A to the gas discharge pipe 52 may be a form in which an inclination is provided on the bottom surface or a form in which a groove portion is provided.

[0024] Also, if the gas discharge pipe 52 and the drain pipe 42 are provided side by side in the middle and the gas discharge pipe is also passed through the gap hole 44 for passing the drain pipe 42 provided in the under cover 40, there is no need to newly provide a gap hole for the gas discharge pipe 52 in the under cover 40, which is economical.

[0025] (Second Embodiment) Figure 2 shows a second embodiment of the present invention, illustrating only the essential parts. 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. In the second embodiment, however, a junction 60 is provided where it merges with the drain pipe 42, and thereafter, a common discharge pipe 54 leads to the outside of the vehicle drive chamber through a gap hole 44 provided in the under cover 40. This configuration makes it 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 gap 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. [Explanation of symbols]

[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: Undercover, 42: Drain pipe, 44: Crevice hole, 46: Firewall, 50: Unit cover, 52: Gas exhaust pipe, 54: Common exhaust pipe, 56: Check valve, 60: Confluence, A: Leaked refrigerant, R: Refrigerant unit

Claims

1. It has a refrigerant circuit in which a flammable refrigerant heavier than air circulates, In a vehicle air conditioning system equipped with a refrigerant unit that integrates the compressor, condenser, evaporator, and accumulator constituting the refrigerant circuit, The aforementioned vehicle air conditioning system is, A closed-bottom unit cover surrounding the side surface of the refrigerant unit, which is formed so that its volume is greater than or equal to a predetermined volume, The unit includes a pipe connecting the bottom surface of the unit cover to the outside of the vehicle's drive chamber, The unit cover has a guide section formed to guide the leaked refrigerant into the piping. A vehicle air conditioning system characterized by the following features.

2. The piping connected to the unit cover is connected to the outside of the vehicle's drive chamber, alongside the drain pipe. The vehicle air conditioning system according to feature 1.

3. The piping connected to the unit cover has a junction with the drain pipe. The vehicle air conditioning system according to feature 1.

4. Near the confluence with the aforementioned drain pipe, a backflow prevention mechanism toward the upstream side of the drain pipe is provided. The vehicle air conditioning system according to feature 3.

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