Vehicle front structure

Abstract

To provide a vehicle front structure that can further improve the space efficiency of the front of the vehicle. [Solution] The front structure of the vehicle comprises a tower bar 14 connecting the left and right suspension towers 12 at the front of the vehicle, and a water-cooled gas cooler 28 that exchanges heat between the refrigerant used in the air conditioning system 20 and water refrigerant. The tower bar 14 is a hollow member having a closed cross-section, and the water-cooled gas cooler 28 is located inside the tower bar 14.

Description

Technical Field

[0001] This specification discloses a vehicle front structure including a heat exchanger that exchanges heat between an air-conditioning refrigerant and water.

Background Art

[0002] Generally, in-vehicle air-conditioning devices move heat by compressing, expanding, evaporating, and condensing the air-conditioning refrigerant during the process of circulating the air-conditioning refrigerant, thereby generating temperature-controlled air-conditioning air. In the flow path of the air-conditioning refrigerant, an air-cooled heat exchanger (such as an air-cooled condenser or an air-cooled gas cooler) that exchanges heat between the air-conditioning refrigerant and the running air is often provided. Furthermore, in recent years, it has also been proposed to provide a water-cooled heat exchanger instead of or in addition to the air-cooled heat exchanger.

[0003] For example, Patent Document 1 discloses a vehicle air-conditioning system including a water-cooled condenser. In Patent Document 1, the water-cooled condenser functions as a condenser that cools and condenses the air-conditioning refrigerant with cooling water from a radiator. Such a water-cooled condenser can be installed in a place where the running air does not hit, and has a high degree of freedom in arrangement compared to an air-cooled condenser.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In this case, most of the air conditioning system, including the heat exchanger, is located in the power unit compartment at the front of the vehicle. The power unit compartment also houses the power source and radiator, in addition to the air conditioning system. Therefore, when attempting to place an air-cooled heat exchanger in the power unit compartment, there are many space constraints, making it difficult to secure sufficient volume for the air-cooled heat exchanger. Furthermore, Patent Document 1 does not consider the placement of an air-cooled condenser.

[0006] Therefore, this specification discloses a vehicle front structure that can further improve the space efficiency of the front of the vehicle. [Means for solving the problem]

[0007] The vehicle front structure disclosed herein comprises, in the front of the vehicle, a tower bar connecting the left and right suspension towers, and a heat exchanger for exchanging heat between a water refrigerant and an air conditioning refrigerant used in an air conditioning system, wherein the tower bar is a hollow member having a closed cross-section, and the heat exchanger is arranged inside the tower bar.

[0008] This configuration further improves the space efficiency at the front of the vehicle.

[0009] In this case, the heat exchanger is a gas cooler in which layers of refrigerant flow paths through which the air conditioning refrigerant flows and layers of water flow paths through which the water refrigerant flows are alternately stacked, and the heat exchanger may be arranged inside the tower bar in a position where the direction of travel of the air conditioning refrigerant flow paths and the longitudinal direction of the tower bar are substantially parallel.

[0010] This configuration ensures sufficient distance for the refrigerant flow path, thereby improving heat exchange efficiency.

[0011] Furthermore, the gas cooler may be positioned approximately at the center of the strut bar in the vehicle width direction, and inlets and outlets for the air conditioning refrigerant and water, respectively, may be provided at both ends of the gas cooler in the vehicle width direction.

[0012] Many other components of the air conditioning system are located near the center of the vehicle's width. Therefore, by placing the gas cooler in the center of the vehicle's width and providing inlets and outlets on both sides, the connection of the piping between the gas cooler and other components can be simplified.

[0013] Furthermore, the air conditioning system provides heating using the heat transferred from the refrigerant to the water refrigerant in the heat exchanger, and the space between the heat exchanger and the inner surface of the tower bar may be filled with insulating material.

[0014] This configuration reduces the leakage of heating heat to the outside, thereby improving the efficiency of the air conditioning system. Furthermore, the installation of insulation material suppresses vibrations in the gas cooler. [Effects of the Invention]

[0015] The technology disclosed herein improves space efficiency in the front of the vehicle. [Brief explanation of the drawing]

[0016] [Figure 1] This is a plan view showing the arrangement of key components in the front of the vehicle. [Figure 2] This is a diagram showing the configuration of an air conditioning system. [Figure 3] This is a cross-sectional view of AA in Figure 1. [Figure 4] This is a disassembled perspective view of the main components of a water-cooled gas cooler. [Figure 5] This is a schematic perspective view of a water-cooled gas cooler. [Modes for carrying out the invention]

[0017] The vehicle's front structure will now be described with reference to the drawings. Figure 1 is a plan view showing the arrangement of key components in the front of the vehicle. As shown in Figure 1, a space called the power unit room 10 is provided between the front end surface of the vehicle and the passenger compartment, in other words, under the vehicle's hood. This power unit room 10 houses, for example, a power source (not shown), a gear unit (not shown), and an air conditioning system 20 (see Figure 2). The power source is, for example, an engine, or a rotary electric motor, or both. In the case of an electric vehicle, a transaxle integrating the gear unit and rotary electric motor is located in the power unit room 10. The air conditioning system 20 has numerous components, such as a compressor 26, an air-cooled gas cooler 30, and an evaporator 44, as will be described later.

[0018] Furthermore, the power unit room 10 is also equipped with suspension towers 12 for mounting the front suspension. As shown in Figure 1, there are two suspension towers 12, one at each end of the power unit room 10 in the vehicle width direction. A tower bar 14 is stretched between the two suspension towers 12. The connection of the two suspension towers 12 by the tower bar 14 improves the rigidity of the vehicle and enhances its handling stability. In addition, the power unit room 10 houses various sensors, wiring, and piping. In other words, the power unit room 10 has always housed a large number of components that are important to the vehicle.

[0019] Next, the configuration of the air conditioner 20 disposed in the power unit room 10 will be described. FIG. 2 is a diagram showing the configuration of the air conditioner 20. In the process of circulating the air-conditioning refrigerant, the air conditioner 20 transfers heat by compressing, expanding, evaporating, and condensing the air-conditioning refrigerant, thereby generating temperature-controlled air-conditioning air. Conventionally, fluorine-based refrigerants have been widely used as the refrigerant of the air conditioner 20. In the air conditioner 20 of this example, a natural refrigerant is used as the air-conditioning refrigerant. A natural refrigerant is a refrigerant mainly composed of substances generated in nature, for example, a carbon compound (such as carbon dioxide or hydrocarbon) or ammonia. Examples of the carbon compound used as the natural refrigerant include carbon dioxide (hereinafter referred to as "CO2") or hydrocarbon (such as propane or butane). Such natural refrigerants have a lower global warming potential and a smaller environmental load compared to fluorine-based refrigerants. For example, the global warming potential of a fluorine-based refrigerant is about 1400, while the global warming potential of a CO2 refrigerant mainly composed of CO2 is 1, which is very small. Hereinafter, an example in which a CO2 refrigerant is adopted as the natural refrigerant will be described.

[0020] The air conditioner 20 has a refrigerant circuit 22 and a blowing mechanism 54. The refrigerant circuit 22 is a circuit that generates heat and latent heat by compressing, expanding, condensing, and evaporating the air-conditioning refrigerant in the process of circulating the air-conditioning refrigerant. The heat generated in this refrigerant circuit 22 is used for heating, and the latent heat is used for cooling. The blowing mechanism 54 is a mechanism that takes in air from outside or inside the vehicle, cools or heats it, and blows it into the vehicle interior. Specifically, the blowing mechanism 54 includes an evaporator 44, a heater core 36, and a blower fan 34. The evaporator 44 is an evaporator that evaporates the atomized air-conditioning refrigerant. The air around the evaporator 44 is cooled by the latent heat generated during this evaporation. Then, the air cooled by the evaporator 44 is sent to the passenger compartment by the blower fan 34, thereby cooling the passenger compartment.

[0021] The heater core 36 is a heat exchanger that exchanges heat between the warm water flowing inside it and the surrounding air. Behind the heater core 36, a mode switching door 40 for switching the flow rate of the air passing through the heater core 36 is arranged. This mode switching door 40 is closed during the cooling operation and opened during the heating operation. When the mode switching door 40 is opened, the air sent from the blower fan 34 is heated by the heater core 36. Then, the heated air is sent to the passenger compartment, thereby heating the passenger compartment.

[0022] The refrigerant circuit 22 has refrigerant pipes 24 through which the air-conditioning refrigerant flows. Along the path of this refrigerant pipe 24, devices for compressing, expanding, condensing, and evaporating the air-conditioning refrigerant, such as a compressor 26, an air-cooled gas cooler 30, a water-cooled gas cooler 28, an accumulator 48, an evaporator 44, etc. are provided. The compressor 26 compresses the gaseous air-conditioning refrigerant. Behind the front grille (not shown), the air-cooled gas cooler 30 is arranged. The air-cooled gas cooler 30 is a heat exchanger that exchanges heat between the air-conditioning refrigerant and the outside air. Behind the air-cooled gas cooler 30, a fan 32 for efficiently taking in the outside air is arranged.

[0023] The accumulator 48 separates the air-conditioning refrigerant output from the air-cooled gas cooler 30 or the evaporator 44 into gas and liquid and sends it to the compressor 26. Also, this accumulator 48 has an internal heat exchanger 50 that exchanges heat between the high-temperature air-conditioning refrigerant and the low-temperature air-conditioning refrigerant. Specifically, the internal heat exchanger 50 exchanges heat between the air-conditioning refrigerant flowing from the air-cooled gas cooler 30 towards the evaporator 44 and the air-conditioning refrigerant flowing from the accumulator 48 towards the compressor 26.

[0024] The water-cooled gas cooler 28 is a heat exchanger that exchanges heat between the high-temperature refrigerant output from the compressor 26 and the water (hereinafter referred to as "water refrigerant") flowing towards the heater core 36. As will be described later, the water-cooled gas cooler 28 has a refrigerant passage 74 through which the refrigerant flows and a water passage 80 through which hot water flows. During heating operation, the high-temperature refrigerant flows through the water-cooled gas cooler 28, heating the water refrigerant and, consequently, the heater core 36. The air that has passed through the heated heater core 36 is then sent to the passenger compartment, thereby heating the passenger compartment. The specific configuration of the water-cooled gas cooler 28 will be described in detail later.

[0025] The heater core 36 and the water-cooled gas cooler 28 are connected by a water circuit 35. The water circuit 35 is a circuit for circulating water coolant. In addition to the heater core 36 and the water-cooled gas cooler 28, the water circuit 35 also includes a water pump 37 and an electric heater 38. The water pump 37 pumps water coolant under pressure as needed. The electric heater 38 heats the water coolant output from the water-cooled gas cooler 28 to a target temperature if the temperature is insufficient. In addition to or instead of the electric heater 38, other heat sources may be provided. For example, waste heat generated by on-board heat-generating elements, such as batteries, motors, or engines, may be used as a heat source to heat the water coolant.

[0026] The refrigerant circuit 22 is further equipped with several valves 56, 58, 60, and 62. During cooling operation, the cooling expansion valve 56 and the cooling solenoid valve 60 are opened, while the heating expansion valve 58 and the heating solenoid valve 62 are closed. In this case, the refrigerant is pressurized by the compressor 26 and then passes through the air-cooled gas cooler 30, the internal heat exchanger 50, and the cooling expansion valve 56. The refrigerant that has passed through the cooling expansion valve 56 becomes a low-pressure mist and is supplied to the evaporator 44. In the evaporator 44, the low-pressure mist of refrigerant evaporates, cooling the air around the evaporator 44. This cooled air is then sent to the passenger compartment by the blower fan 34, cooling the passenger compartment. In the evaporator 44, the evaporated gaseous refrigerant is sent to the accumulator 48, where it is separated into gas and liquid. The gaseous refrigerant for air conditioning is then supplied back to the compressor 26.

[0027] On the other hand, during heating operation, the heating expansion valve 58 and heating solenoid valve 62 are opened, while the cooling expansion valve 56 and cooling solenoid valve 60 are closed. In this case, the refrigerant is pressurized to high temperature and high pressure by the compressor 26 and then supplied to the water-cooled gas cooler 28. In the water-cooled gas cooler 28, the water refrigerant, and consequently the heater core 36, is heated by this high-temperature, high-pressure refrigerant. The air that has passed through the high-temperature heater core 36 is then sent to the passenger compartment, heating the compartment. The refrigerant that has passed through the water-cooled gas cooler 28 is depressurized by the heating expansion valve 58 and then sent to the air-cooled gas cooler 30. In the air-cooled gas cooler 30, the refrigerant receives heat from the outside air and some or all of it vaporizes. After being output from the air-cooled gas cooler 30, the refrigerant is separated into gas and liquid in the accumulator 48. The gaseous refrigerant is then supplied back to the compressor 26.

[0028] As is clear from the above explanation, the air conditioning unit 20 has numerous components, most of which are located in the power unit room 10. In addition to the air conditioning unit 20, the power unit room 10 also houses a power source, a transmission mechanism, and other components. Therefore, there is very little extra space in the power unit room 10. In particular, as mentioned above, in this example, a CO2 refrigerant, mainly composed of CO2, is used as the air conditioning refrigerant. CO2 refrigerant needs to be pressurized to a higher pressure than fluorine-based refrigerants. In this case, a compressor 26 with a higher output and larger size must be used compared to when using a fluorine-based refrigerant. As a result, when using CO2 refrigerant, there is very little extra space in the power unit room 10.

[0029] Therefore, in this example, in order to make effective use of the space in the power unit room 10, the water-cooled gas cooler 28 is placed inside the tower bar 14. This will be explained with reference to Figures 3 to 5. Figure 3 is a cross-sectional view of AA in Figure 1. Figure 4 is an exploded perspective view of the main part of the water-cooled gas cooler 28, and Figure 5 is a schematic perspective view of the water-cooled gas cooler 28.

[0030] The water-cooled gas cooler 28 has fin plates 70 and tube plates 76 arranged alternately in the upper and lower directions. The fin plates 70 are made of a metal with high thermal conductivity, such as aluminum. The fin plates 70 have a plurality of fins 72 arranged at intervals in the vehicle's longitudinal direction. Each fin 72 bulges alternately towards the front and rear of the vehicle as it moves in the vehicle's width direction. As a result, a zigzag, meandering passage is formed between two adjacent fins 72 in the vehicle's longitudinal direction. This passage becomes a water channel 80 through which the water coolant flows. Note that this configuration of the fin plates 70 is just an example and may be modified as appropriate. For example, the number of fins 72 and the shape of the fins 72 may be changed as appropriate.

[0031] The tube plate 76 is a plate-shaped member made of a metal with high thermal conductivity, such as aluminum. Multiple through holes 78 are formed in this tube plate 76, penetrating in the vehicle width direction and spaced apart in the vehicle's longitudinal direction. These through holes 78 function as refrigerant passages 74 through which the air conditioning refrigerant flows.

[0032] The fin plates 70 and tube plates 76 are stacked alternately on top of each other to form a laminate 79. That is, the water-cooled gas cooler 28 has layers of refrigerant passages 74 and layers of water passages 80 stacked alternately. Closure covers 82 are attached to both ends of this laminate 79 in the vehicle's longitudinal direction. The closure covers 82 close the refrigerant passages 74 at the ends of the vehicle from the vehicle's longitudinal direction in order to prevent leakage of air conditioning refrigerant from the refrigerant passages 74 located at those ends. As shown in Figure 5, the front closure cover 82 is fitted with a water inlet 90 and a water outlet 92. The water inlet 90 and water outlet 92 are attached near both ends of the front closure cover 82 in the vehicle's width direction. Furthermore, end plates 84 are placed at both ends of the laminate 79 in the vehicle's width direction. One of these two end plates 84 is provided with a refrigerant inlet 86, and the other is provided with a refrigerant outlet 88.

[0033] Inside the closing cover 82 and end plate 84, there is a distribution channel (not shown) that branches and guides the water refrigerant and air conditioning refrigerant supplied via the water inlet 90 and refrigerant inlet 86 into a plurality of water channels 80 and refrigerant channels 74. Furthermore, inside the closing cover 82 and end plate 84, there is also a merging channel (not shown) that combines the water refrigerant and air conditioning refrigerant that have passed through the plurality of water channels 80 and refrigerant channels 74 and guides them to the water outlet 92 and refrigerant outlet 88.

[0034] Here, the water refrigerant and the air conditioning refrigerant flow in opposite directions. In Figure 4, the solid arrows indicate the direction of water refrigerant flow, and the dashed arrows indicate the direction of air conditioning refrigerant flow. In the example in Figure 4, the air conditioning refrigerant flows from the right side of the page to the left side, and the water refrigerant flows from the left side of the page to the right side. To match this flow, the water inlet 90 and the refrigerant inlet 86 are located on opposite sides of each other, and the water outlet 92 and the refrigerant outlet 88 are located on opposite sides of each other. That is, in this example, the water inlet 90 and the refrigerant outlet 88 are located near the left end of the water-cooled gas cooler 28, and the refrigerant inlet 86 and the water outlet 92 are located near the right end of the water-cooled gas cooler 28.

[0035] As shown in Figures 1 and 3, the water-cooled gas cooler 28 is located inside the tower bar 14. This will be explained in detail. As shown in Figure 3, the tower bar 14 is constructed by joining a tower bar upper 16 and a tower bar lower 18. The cross-sectional shape of the tower bar upper 16 is roughly hat-shaped with an opening on the lower side, and the cross-sectional shape of the tower bar lower 18 is roughly hat-shaped with an opening on the upper side. The tower bar 14 is constructed by overlapping and joining the parts corresponding to the "flanges" of these two hat shapes. An internal space is formed between the tower bar upper 16 and the tower bar lower 18, with a length in the vehicle width direction. In other words, the tower bar 14 is a hollow member with a closed cross-section. In this example, the water-cooled gas cooler 28 is located in this internal space. In other words, the water-cooled gas cooler 28 is positioned inside the tower bar 14 with the direction of travel of the refrigerant flow path 74 and the water flow path 80 parallel to the vehicle width direction, and the stacking direction of the fin plate 70 and the tube plate 76 being vertical.

[0036] Here, the internal space of the tower bar 14 is a space that has not been utilized as dead space in the past. By placing the water-cooled gas cooler 28 in this internal space, the space efficiency of the power unit room 10 is improved, and space for mounting a large compressor 26 can be secured. However, in order for the water-cooled gas cooler 28 to perform at its full capacity, it is necessary to ensure sufficient flow distance for the refrigerant flow path 74 and the water flow path 80. In this example, the direction of travel of the refrigerant flow path 74 and the water flow path 80 of the tower bar 14 is parallel to the longitudinal direction. Therefore, it is easy to ensure the flow distance for the refrigerant flow path 74 and the water flow path 80, and the heat exchange efficiency of the water-cooled gas cooler 28 can be improved.

[0037] As shown in Figure 3, the gap between the water-cooled gas cooler 28 and the inner surface of the tower bar 14 is filled with thermal insulation material 94. The thermal insulation material 94 is, for example, foamed resin or felt. For example, a sheet of thermal insulation material before foaming may be attached to the inside of the tower bar 14, and after placing the water-cooled gas cooler 28 inside the tower bar 14, the tower bar 14 may be heated to cause the thermal insulation material to foam. In this configuration, the thermal insulation material expands to match the shape of the water-cooled gas cooler 28, so that the gap between the water-cooled gas cooler 28 and the inner surface of the tower bar 14 is properly filled with thermal insulation material.

[0038] In any case, by filling the space between the water-cooled gas cooler 28 and the inner surface of the tower bar 14 with insulating material 94, the water-cooled gas cooler 28 is effectively insulated. This reduces the amount of heat used for heating that leaks to the outside, thus improving the overall energy efficiency of the vehicle. In addition, filling the space with insulating material 94 suppresses vibrations of the water-cooled gas cooler 28. As a result, damage to the water-cooled gas cooler 28 is effectively prevented, and noise is also suppressed.

[0039] As repeatedly stated, in this example, a water-cooled gas cooler 28 is placed inside the tower bar 14. The water-cooled gas cooler 28 is constructed by laminating multiple metal parts and is a highly rigid component. By placing this water-cooled gas cooler 28 inside the tower bar 14, the rigidity of the tower bar 14 is improved. This, in turn, further improves the vehicle's handling stability.

[0040] As shown in Figure 1, the water-cooled gas cooler 28 is positioned approximately in the center of the strut bar 14 in the vehicle width direction. Here, many of the components of the air conditioning system 20, including the compressor 26, are positioned in the center of the vehicle width direction. Therefore, by positioning the water-cooled gas cooler 28 in the center in the vehicle width direction and providing inlets 86, 90 and outlets 88, 92 on both sides of it, the connection of piping between the gas cooler and other elements can be simplified.

[0041] The water-cooled gas cooler 28 is connected to the piping of the refrigerant circuit 22 and the piping of the water circuit 35. To connect these pipes to the water-cooled gas cooler 28, the tower bar 14, for example, the lower tower bar 18, may have openings through which the pipes can pass. However, if the water-cooled gas cooler 28 is placed inside the tower bar 14, the maintainability of the water-cooled gas cooler 28 may be reduced. Therefore, a maintenance opening may be provided in a part of the tower bar 14. In this case, the maintenance opening may be large enough for the water-cooled gas cooler 28 to pass through. The maintenance opening may also be covered with a cover that can be attached to and removed from the tower bar 14. For example, the cover may be fastened to the tower bar 14 with bolts.

[0042] In any case, as is clear from the above explanation, since the water-cooled gas cooler 28 is located inside the tower bar 14, the space efficiency of the power unit room 10 can be further improved. Note that the configuration described above is just one example, and other configurations may be changed as long as the configuration of claim 1 is met. For example, the heat insulating material 94 between the water-cooled gas cooler 28 and the tower bar 14 may be omitted. The configuration of the water-cooled gas cooler 28 may also be changed as appropriate. In this example, the water-cooled gas cooler 28 is used for heating the vehicle cabin, but the water-cooled gas cooler 28 may be used for other purposes. For example, the water-cooled gas cooler 28 may be used for the purpose of cooling on-board components. [Explanation of Symbols]

[0043] 10 Power unit room, 12 Suspension tower, 14 Tower bar, 16 Tower bar upper, 18 Tower bar lower, 20 Air conditioning unit, 22 Refrigerant circuit, 24 Refrigerant piping, 26 Compressor, 28 Water-cooled gas cooler, 30 Air-cooled gas cooler, 32 Fan, 34 Blower fan, 35 Water circuit, 36 Heater core, 37 Water pump, 38 Electric heater, 40 Mode switching door, 44 Evaporator, 48 Accumulator, 50 Internal heat exchanger, 54 Discharge mechanism, 56 Cooling expansion valve, 58 Heating expansion valve, 60 Cooling solenoid valve, 62 Heating solenoid valve, 70 Fin plate, 72 Fins, 74 Refrigerant flow path, 76 Tube plate, 78 Through hole, 79 Laminate, 80 Water flow path, 82 Closing cover, 84 End plate, 86 Refrigerant inlet, 88 Refrigerant outlet, 90; Water inlet, 92; Water outlet, 94; Insulation.

Claims

1. At the front of the vehicle, a tower bar connects the left and right suspension towers, A heat exchanger that exchanges heat between the refrigerant used in an air conditioning system and a water refrigerant, Equipped with, The tower bar is a hollow member having a closed cross-section, The heat exchanger is located inside the tower bar. A vehicle front structure characterized by the following features.

2. The vehicle front structure according to claim 1, The heat exchanger is a gas cooler in which layers of refrigerant channels through which the air conditioning refrigerant flows and layers of water channels through which the water refrigerant flows are alternately stacked. The heat exchanger is positioned inside the tower bar in such a manner that the direction of flow of the air conditioning refrigerant and the longitudinal direction of the tower bar are substantially parallel. A vehicle front structure characterized by the following features.

3. The vehicle front structure according to claim 2, The aforementioned gas cooler is positioned approximately at the center of the strut bar in the vehicle width direction. Inlets and outlets for the air conditioning refrigerant and water, respectively, are provided at both ends of the gas cooler in the vehicle width direction. A vehicle front structure characterized by the following features.

4. The vehicle front structure according to claim 1, The aforementioned air conditioning system provides heating using the heat transferred from the refrigerant to the water refrigerant in the heat exchanger. The space between the heat exchanger and the inner surface of the tower bar is filled with insulating material. A vehicle front structure characterized by the following features.

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