Vehicle lower structure

Abstract

This invention relates to a vehicle underbody structure to suppress heat damage caused by an exhaust pipe to a unit component disposed below a floor panel. The vehicle underbody structure includes: an exhaust pipe; a unit component adjacent to the exhaust pipe; a heat insulation body protecting the unit component from the heat of the exhaust pipe; and a protective plate mounted on the front of the unit component. The vehicle underbody structure includes a heat insulation cover component disposed in front of the unit component, covering the lower part of the exhaust pipe to cover the heat insulation body. The heat insulation cover component has: a shielding wall portion that shields the area between the exhaust pipe and the protective plate, extending downward along the exhaust pipe from the engine compartment side to the underbody side; and a second opening portion that opens downward toward the vehicle.

Description

Technical Field

[0001] This invention relates to the underbody structure of vehicles. Background Technology

[0002] Patent document 1 discloses a vehicle lower structure comprising: a battery pack disposed below a floor panel; a bracket for protecting the battery pack from road surface interference; an exhaust pipe extending along the side of the battery pack; and a heat insulation component disposed between the battery pack and the exhaust pipe.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-140678

[0004] In the structure described in Patent Document 1, when hot air flows from the engine compartment to the battery pack side, the hot air flows into the space above the bracket and remains in the space in front of the battery pack covered by the bracket, which may cause thermal damage to the battery pack. Summary of the Invention

[0005] The present invention was made in view of the above circumstances, and its object is to provide a vehicle underbody structure capable of suppressing thermal damage caused by exhaust pipes generated by unit components disposed below the floor panel.

[0006] The vehicle lower structure of the present invention includes: an exhaust pipe connected to an engine housed in an engine compartment at the front of the vehicle and extending toward the rear of the vehicle; a unit component disposed below the floor panel of the vehicle and behind the engine compartment, adjacent to the exhaust pipe; a heat shield protecting the unit component from the heat of the exhaust pipe; a protective plate mounted on the front of the unit component to protect the unit component from road surface interference; and a bottom cover covering the lower part of the vehicle. The vehicle lower structure is characterized by having a heat shield cover component disposed on the exhaust pipe. The unit component is located in front of the exhaust pipe, which is covered by the lower part of the exhaust pipe and the heat insulation body. The bottom cover has a first opening that exposes a portion of the heat insulation cover component. The outer peripheral surface of the exhaust pipe is covered in front of the unit component by the heat insulation cover component and the heat insulation body. The heat insulation cover component has: a shielding wall that shields the exhaust pipe from the protective plate and extends downward along the exhaust pipe from the engine compartment side to the bottom cover side; and a second opening that opens downward toward the vehicle and communicates with the lower space of the vehicle via the first opening.

[0007] In this invention, heat damage caused by exhaust pipes generated by unit components disposed below the floor panel can be suppressed. Attached Figure Description

[0008] Figure 1This is a diagram schematically illustrating a vehicle used in an implementation method.

[0009] Figure 2 It is a skeleton diagram used to illustrate the structure of a vehicle.

[0010] Figure 3 It is a schematic diagram showing the lower structure of a vehicle.

[0011] Figure 4 It is a diagram used to illustrate the lower structure of a vehicle.

[0012] Figure 5 It is a diagram used to illustrate the configuration relationship between the heat insulation cover component, the exhaust pipe, the heat insulation body, and the bottom cover.

[0013] Figure 6 This is a diagram used to illustrate the shielding space covered by the heat insulation cover component and the heat insulation.

[0014] Figure 7 It is a diagram used to illustrate the airflow when hot air in a sheltered space is released into the space below.

[0015] Figure 8 This diagram illustrates the situation where hot air flowing through the shielded space exits from the opening of the heat insulation cover component through the opening of the bottom cover into the space below.

[0016] Figure 9 This is a diagram used to illustrate the lower structure of the vehicle in the modified example. Detailed Implementation

[0017] The vehicle lower structure according to an embodiment of the present invention will now be described in detail. However, the present invention is not limited to the embodiments described below.

[0018] Figure 1 This is a schematic diagram illustrating the vehicle in the embodiment. Vehicle 1 is a hybrid vehicle. Figure 1 , Figure 2 As shown, vehicle 1 includes an engine 2, a battery pack 3, a fuel tank 4, an exhaust pipe 5, a floor panel 6, a bottom cover 7, a heat shield 8, a protective plate 9, a front suspension frame 10, front wheels 11, and rear wheels. Figure 3 As shown, vehicle 1 has a heat shield cover component 20 as its lower structure.

[0019] Engine 2 is located at the front of vehicle 1. An engine compartment is provided at the front of vehicle 1, and engine 2 is housed inside the engine compartment.

[0020] Battery pack 3 is located below floor panel 6. Battery pack 3 is a unit component mounted behind the engine compartment and under the floor of vehicle 1. Battery pack 3 includes multiple battery modules and a housing for storing the battery modules. The housing consists of a lower housing and a top cover. The battery modules and a junction box are housed inside the housing. The junction box is located at the front of the lower housing. Figure 2 As shown, the exhaust pipe 5 is adjacent to the battery pack 3.

[0021] The fuel tank 4 is located at the rear of the battery pack 3.

[0022] Exhaust pipe 5 is connected to engine 2, allowing exhaust from engine 2 to flow to the outside of vehicle 1. A catalytic converter and muffler are connected to exhaust pipe 5. Exhaust pipe 5 extends downwards and rearwards from the engine compartment, and extends towards the rear of vehicle 1 below floor panel 6. The exhaust outlet of exhaust pipe 5 is located at the rear of vehicle 1 and opens rearwards. Figure 1 As shown, in front of the battery pack 3, the exhaust pipe 5 extends downwards from the engine compartment toward the underbody 7. Figure 2 As shown, the exhaust pipe 5 extends from the engine compartment toward the rear, passing above the front suspension component 10.

[0023] like Figure 2 , Figure 3 As shown, the exhaust pipe 5 has a curved portion 5a that bends in the front direction of the battery pack 3 in the vehicle width direction. The exhaust pipe 5 is disposed near the battery pack 3 and extends along the side of the battery pack 3. The exhaust pipe 5 extends outward from the battery pack 3 toward the rear of the vehicle 1 in the vehicle width direction.

[0024] The underbody cover 7 is a protective component that covers the lower part of the vehicle 1. The underbody cover 7 is a component used to protect the vehicle 1 from road surface interference. The underbody cover 7 includes multiple components, such as a common panel disposed below the battery pack 3.

[0025] The heat insulation element 8 is a heat-insulating component that protects the unit component from the heat of the exhaust pipe 5. This unit component is mounted under the floor of the vehicle 1. The heat insulation element 8 is used to suppress heat damage to the unit component caused by the exhaust pipe 5. Figure 2 , Figure 3 As shown, the heat insulation body 8 covers the outer peripheral surface of the exhaust pipe 5 and is disposed along the extending direction of the exhaust pipe 5. The heat insulation body 8 is disposed above and to the side of the exhaust pipe 5. The wall surface of the heat insulation body 8 faces the outer peripheral surface of the exhaust pipe 5.

[0026] The protective plate 9 is a rigid component installed at the front of the battery pack 3 to protect it from road surface interference. The protective plate 9 also functions as a fall protection component to protect the battery pack 3 from falling objects. Figure 3As shown, a protective plate 9 is fixed to the bottom wall of the lower housing of the battery pack 3. The protective plate 9 is fastened to the lower housing by fastening components. The protective plate 9 connects the front suspension frame 10 and the battery pack 3. The front part of the protective plate 9 is mounted on the front suspension frame 10, and the rear part of the protective plate 9 is mounted on the battery pack 3. The front suspension frame 10 supports the left and right front wheels 11. Figure 2 , Figure 3 As shown, the protective plate 9 is positioned on the left side of the bend 5a of the exhaust pipe 5 in the vehicle width direction.

[0027] In this vehicle 1 configuration, a heat shield 8 is provided for the exhaust pipe 5, which extends rearward and downward from the engine compartment. Since the wall of the heat shield 8 extends to the vicinity of the underbody cover 7, space for wheel arches, piping, etc., is lost, resulting in a low wall of the heat shield 8. Consequently, hot air leaks outward from the wall of the heat shield 8 in front of the battery pack 3. As a result, the heat from the hot air reaches the battery pack 3 above the protective plate 9. Therefore, in the lower structure of the vehicle 1, a heat shield cover component 20 is provided as the lower surface of the heat shield 8.

[0028] The heat shield cover component 20 is positioned in front of the battery pack 3, covering the heat shield 8 and the exhaust pipe 5 opposite to the lower surface of the exhaust pipe 5. The heat shield cover component 20 is used to suppress thermal damage to the battery pack 3 caused by high-temperature air from the engine compartment and to suppress further thermal damage caused by high-temperature air from the exhaust pipe 5. Assuming that the unit components are exposed to high-temperature air, the seals and electrical components deteriorate, affecting durability. In this case, the high-temperature air in the engine compartment receives heat from the exhaust pipe 5 and flows towards the unit components. Furthermore, the lower part of the heat shield 8 is open, so high-temperature air leaking downwards reaches the unit components. Therefore, to prevent the unit components from being exposed to high-temperature air, the heat shield cover component 20 blocks the flow of high-temperature air from the engine compartment side to the battery pack 3 side. Specifically, the heat shield cover component 20 blocks the flow of air from the engine compartment side to the space above the protective plate 9.

[0029] like Figure 3 As shown, the heat insulation cover component 20 is disposed near the bend 5a of the exhaust pipe 5. For example, the heat insulation cover component 20 is disposed upstream of the bend 5a of the exhaust pipe 5. The heat insulation 8 forms a wall downstream of the bend 5a, so hot air does not flow to the battery pack 3.

[0030] like Figure 4 As shown, the bottom cover 7 has a first opening 7a that exposes a portion of the heat insulation cover component 20. The exhaust pipe 5 is configured to avoid the front suspension frame component 10, so it is preferable to provide the first opening 7a in the portion near the bend 5a.

[0031] like Figure 5 , Figure 6 As shown, in front of the battery pack 3, the outer peripheral surface of the exhaust pipe 5 is covered by a heat insulation cover component 20 and a heat insulation body 8. The heat insulation cover component 20 and the heat insulation body 8 together surround the exhaust pipe 5 to define a shielding space S1. The shielding space S1 is the space in which the walls of the heat insulation cover component 20 and the heat insulation body 8 cover the outer peripheral surface of the exhaust pipe 5. The heat insulation cover component 20 has a shielding wall portion 20a, a second opening portion 20b, and a lower wall portion 20c.

[0032] The shielding wall 20a is the wall that shields the exhaust pipe 5 and the protective plate 9. The shielding wall 20a extends rearward and downward along the exhaust pipe 5 from the engine compartment side to the bottom cover 7 side.

[0033] The second opening 20b is a downward-facing opening, serving as an outlet for the high-temperature air within the shielded space S1 to flow downwards into the vehicle 1. The second opening 20b communicates with the lower space S2 of the vehicle 1 via the first opening 7a. Figure 5 As shown, the first opening 7a is located in the height direction near the lower end of the heat insulation cover component 20. At least a portion of the second opening 20b is located in front of the first opening 7a.

[0034] like Figure 5 As shown, in order to suppress thermal damage to the protective plate 9 from the exhaust pipe 5, a first opening 7a and a second opening 20b are provided near the front of the engine compartment where hot air descends rearward and downward. That is, the rear end of the heat insulation cover component 20 is provided in conjunction with the location where the first opening 7a needs to be provided on the bottom cover 7.

[0035] like Figure 4 As shown, a leg 12 is mounted on the exhaust pipe 5. The leg 12 is a component that mounts the exhaust pipe 5 to the vehicle body. The exhaust pipe 5 is supported by the leg 12. The leg 12 is located near the bend 5a of the exhaust pipe 5. In the heat insulation cover component 20, a cutout is provided near the leg 12 to create a space for releasing high-temperature air to the outside. This cutout becomes a second opening 20b for releasing high-temperature air downwards.

[0036] The lower wall portion 20c is positioned below the exhaust pipe 5, facing the outer periphery of the exhaust pipe 5 from below. For example... Figure 4 As shown, the shielding wall portion 20a and the lower wall portion 20c are positioned near the bend 5a of the exhaust pipe 5 to shield the high-temperature air flowing towards the battery pack 3. Figure 5 As shown, the lower wall portion 20c is an inclined wall portion extending rearward and downward along the exhaust pipe 5. Figure 4 , Figure 5 , Figure 6 As shown, a portion of the lower wall portion 20c is positioned above the base cover 7. The second opening 20b is located near the lower end of the lower wall portion 20c.

[0037] like Figure 5 As shown, within the area where the lower wall portion 20c is located, the cross-sectional area of ​​the shielding space S1 is small, resulting in a state of high pressure loss. In other words, reducing the cross-sectional area of ​​the shielding space S1 increases the pressure loss of the high-temperature air flowing in the shielding space S1.

[0038] like Figure 7 , Figure 8 As shown, the heat insulation cover component 20 adjusts the flow of high-temperature air in front of the battery pack 3. The negative pressure of the external air passage below the bottom cover 7 is utilized relative to the gap hole located in the middle of the heat insulation cover component 20. In the second opening 20b near the leg portion 12, the flow of air 41 below the bottom cover 7 creates a flow where high-temperature air 32 in the shielding space S1 is dragged towards the lower space S2, merging below the bottom cover 7, and the high-temperature air 42 flows downwards. At this time, the air 41 flowing below the first opening 7a of the bottom cover 7 creates a negative pressure state in the lower space S2. When the vehicle 1 is in motion, the high-temperature air 32 near the exhaust pipe 5 is drawn downwards from the first opening 7a of the bottom cover 7. Furthermore, by reducing the cross-sectional area of ​​the shielding space S1 to increase pressure loss, the flow rate of the high-temperature air 32 can be slowed down, while the flow rate of air 41 relatively increases, increasing the effect of the negative pressure. In this way, the high-temperature air 42 can be released below the bottom cover 7, suppressing thermal damage to the battery pack 3. Therefore, battery pack 3 can be protected from exposure to high-temperature air.

[0039] Furthermore, since the heat insulation body 8 forms the front wall of the battery pack 3, the high-temperature air that collides with the heat insulation body 8, which serves as the front wall, flows downwards towards the floor. This prevents the high-temperature air from flowing towards the battery pack 3.

[0040] Furthermore, the hot air within the shielding space S1 flows downwards toward the bottom cover 7, so although the temperature of the bottom cover 7 may sometimes rise due to this hot air, the battery pack 3 remains separated from the bottom cover 7. Therefore, thermal damage to the battery pack 3 caused by the heat path through the bottom cover 7 can be suppressed.

[0041] As explained above, according to the embodiment, the flow of high-temperature air in front of the battery pack 3 can be adjusted by the heat insulation cover component 20, which can suppress the thermal damage to the battery pack 3 caused by the exhaust pipe 5.

[0042] Furthermore, in a modified example of the lower structure of vehicle 1, such as Figure 9As shown, a double-walled pipe 50 with heat insulation function is provided around the exhaust pipe 5. The double-walled pipe 50 has an outlet portion 50a that opens downwards. The bottom cover 7 has a first opening portion 7a provided near the outlet portion 50a of the double-walled pipe 50. When the vehicle 1 is in motion, the airflow below the bottom cover 7 is used to create a structure that uses negative pressure to drag the high-temperature air inside the double-walled pipe 50 to the outside. According to this modified example, the temperature on the outside of the double-walled pipe 50 is low, so the distance from the double-walled pipe 50 to the bottom cover 7 can be made closer. As a result, the degree of freedom in setting the first opening portion 7a is increased.

[0043] Explanation of reference numerals in the attached figures

[0044] 1…vehicle; 2…engine; 3…battery pack; 4…fuel tank; 5…exhaust pipe; 6…floor panel; 7…underbody; 8…heat shield; 9…protective plate; 10…front suspension component; 11…front wheel; 12…legs; 20…heat shield cover component.

Claims

1. A vehicle substructure comprising: The exhaust pipe is connected to the engine housed in the engine compartment at the front of the vehicle and extends toward the rear of the vehicle. The unit component is located below the floor panel of the vehicle and behind the engine compartment, adjacent to the exhaust pipe; A heat insulation element protects the unit components from the heat of the exhaust pipe; A protective plate, installed at the front of the unit component, protects the unit component from road surface interference; and A bottom cover, which covers the lower part of the vehicle. The vehicle's lower structure is characterized by the following features: The unit includes a heat insulation cover component, which is positioned in front of the unit and covers the lower part of the exhaust pipe to cover the heat insulation. The bottom cover has a first opening that exposes a portion of the heat insulation cover component. The outer peripheral surface of the exhaust pipe is covered in front of the unit component by the heat insulation cover component and the heat insulation. The heat insulation cover component has: The shielding wall covers the space between the exhaust pipe and the protective plate, and extends downward along the exhaust pipe from the engine compartment side to the bottom cover side; and The second opening faces downwards from the vehicle. The second opening communicates with the space below the vehicle via the first opening.

2. The vehicle substructure according to claim 1, characterized in that, The heat insulation cover component has a lower wall portion, which is disposed below the exhaust pipe and opposite to the lower part of the outer peripheral surface of the exhaust pipe. The second opening is located near the lower end of the lower wall portion.

3. The vehicle substructure according to claim 2, characterized in that, At least a portion of the second opening is positioned forward of the first opening.

4. The vehicle substructure according to claim 3, characterized in that, The first opening is located near the heat insulation cover component in the height direction.

5. The vehicle substructure according to any one of claims 1 to 4, characterized in that, The unit component includes a battery pack.

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