Undercovers for vehicles and the underside of vehicles

Abstract

The present invention provides a vehicle and an underbody cover for a vehicle that can suppress the temperature rise of resin components located under the vehicle floor. [Solution] The vehicle comprises a heat source located under the vehicle floor, a first under cover located under the vehicle floor and covering the heat source from below, and a resin component located under the vehicle floor. The resin component is located between the heat source and the first under cover in the vertical direction of the vehicle, and is located outside the vehicle beyond the heat source in the vehicle width direction. In the first under cover, the opposing surface facing the heat source is made of metal, and at least a portion of the opposing surface is covered with a low-reflectance material that has a lower reflectivity of radiation than metal.

Description

Technical Field

[0001] The present invention relates to a vehicle and an under cover for under the vehicle floor.

Background Art

[0002] Patent Document 1 discloses a vehicle body lower structure in which an under cover is disposed below an exhaust pipe, and an opening is provided in the under cover to protect a resin component (resin casing of an exhaust shutter valve) provided in the exhaust pipe from heat damage.

Prior Art Documents

Patent Documents

[0003] [[ID=H22]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a scene where the running wind cannot be introduced while the vehicle is stopped, there is a problem that a cooling effect cannot be obtained.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a vehicle and an under cover for under the vehicle floor capable of suppressing a temperature rise of a resin component disposed under the vehicle floor.

Means for Solving the Problems

[0006] A vehicle according to one aspect of the present invention comprises a heat source located under the vehicle floor, a first under cover located under the vehicle floor and covering the heat source from below, and a resin component located under the vehicle floor. The resin component is located between the heat source and the first under cover in the vertical direction of the vehicle, and is located outside the vehicle beyond the heat source in the vehicle width direction. In the first under cover, the opposing surface facing the heat source is made of metal, and at least a portion of the opposing surface is covered with a low-reflectance material that has a lower reflectivity of radiation than the metal. [Effects of the Invention]

[0007] According to one aspect of the present invention, it is possible to suppress the temperature rise of resin components located under the vehicle floor. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing an example of the configuration of the underbody structure of a vehicle according to an embodiment of the present invention. [Figure 2] Figure 2 is a magnified view of the underbody structure shown in Figure 1, specifically the under cover and its surrounding area. [Figure 3] Figure 3 is a cross-sectional view obtained by cutting Figure 2 along line AA', which is parallel to the vehicle width direction and passes through the underbody cover. [Figure 4] Figure 4 is a schematic cross-sectional view showing an example of the configuration 1 of an undercover according to an embodiment of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view showing an example of the configuration 2 of an undercover according to an embodiment of the present invention. [Figure 6] Figure 6 is a cross-sectional view obtained by cutting Figure 2 along the BB' line, which is parallel to the vehicle's longitudinal direction and passes through the underbody cover. [Figure 7] Figure 7 is a magnified view of the underbody structure shown in Figure 6, specifically the undercover 3 and its surrounding area. [Figure 8] Figure 8 is an example of the underbody diagram of the vehicle shown in Figure 2, but with the under cover removed. [Figure 9]Figure 9 is a magnified view of the connection point between the catalyst and the harness shown in Figure 8, and its vicinity. [Figure 10] Figure 10 is a graph showing the experimental results conducted by the inventor. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings. In the drawings referred to in the following description, identical or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the ratios of thickness and length of each part may differ from those of reality.

[0010] (Example configuration) Figure 1 is a schematic diagram showing an example of the underbody structure of a vehicle 1 according to an embodiment of the present invention. Figure 2 is a magnified view of the underbody structure shown in Figure 1, specifically the under cover 3 and its surrounding area. Figure 3 is a cross-sectional view obtained by cutting Figure 2 along line AA', which is parallel to the vehicle width direction and passes through the under cover 3.

[0011] As shown in Figures 1 to 3, the vehicle 1 according to this embodiment includes an exhaust pipe 2 located under the vehicle floor, an under cover 3 (an example of the "(first) under cover" of the present invention) attached to the underside of the vehicle floor and covering the front side of the center tunnel 23 (i.e., the front side in the longitudinal direction of the vehicle) from below, a resin floor under cover 4 (an example of the "second under cover" of the present invention) attached to the underside of the vehicle floor and covering the metal floor panel 8 (an example of the "vehicle floor" of the present invention) that forms the floor surface of the vehicle body from below, and a front under cover 5 that covers the engine compartment from below.

[0012] A center tunnel 23 is provided in the floor panel 8. The center tunnel 23 extends in the longitudinal direction of the vehicle from the center in the width direction of the vehicle and has an open shape at the bottom. Inside the center tunnel 23, a heat shield layer 24 is provided along the shape of the center tunnel 23.

[0013] In a center tunnel 23 provided with a heat insulation layer 24, an exhaust pipe 2 and a catalyst 21 (an example of the "heat source" of the present invention) connected to the exhaust pipe 2 are provided. The catalyst 21 is, for example, a three-way catalyst or a GPF (Gasoline Particulate Filter). The catalyst 21 is configured to have a larger diameter and a relatively larger heat capacity than the exhaust pipe 2.

[0014] The under cover 3 is attached under the vehicle body floor so as to cover at least a part (for example, a front part in the vehicle longitudinal direction) of the catalyst 21 provided in the center tunnel 23. The under cover 3 is not provided with a through hole for allowing the running wind during vehicle travel to flow into the center tunnel 23.

[0015] The front end portion 3FE of the under cover 3 is fastened to the suspension member 51 by fastening members 39 such as bolts and nuts. The left and right end portions 3SE of the under cover 3 are fastened to tunnel frames (not shown) provided on both the left and right sides of the center tunnel 23 by the fastening members 39. Further, the under cover 3 is connected to the floor under cover 4 and the front under cover 5 by the fastening members 39, respectively.

[0016] The under cover 3 protects components such as the catalyst 21, the exhaust pipe 2 connected to the catalyst 21, and the exhaust temperature sensor 7 from splash stones. For example, as shown by the broken line in FIG. 1, when the vehicle 1 turns the steering wheel to the right and moves forward, the under cover 3 is located behind the front tire 6R. In that case, the under cover 3 serves to protect the components so that the splash stone JS from the right front tire 6R does not contact the components such as the catalyst 21, the exhaust pipe 2, and the exhaust temperature sensor 7. Similarly, when the vehicle 1 turns the steering wheel to the left and moves forward, the under cover 3 serves to protect the components so that the splash stone JS from the left front tire 6L does not contact the components such as the catalyst 21 and the exhaust temperature sensor 7.

[0017] The under cover 3 has a facing surface 3a that faces the catalyst 21 when attached under the vehicle floor. This facing surface 3a is made of a metal such as aluminum or stainless steel, for example. At least a part of this facing surface 3a is covered with a low-reflectivity material that has a lower reflectivity of radiation than the metal constituting the facing surface 3a. Thereby, the under cover 3 can suppress reflecting the radiation (thermal radiation) from the catalyst 21 serving as a heat source on the facing surface 3a.

[0018] For example, as shown in FIG. 3, around the under cover 3, there is a resin floor under cover 4 as a resin component. A part of the floor under cover 4, specifically, the end portion 41 on the center tunnel 23 side, is located at a position facing the catalyst 21 serving as a heat source. Also, this end portion 41 is located in the radiation reflection direction by the under cover 3. Therefore, both the radiation H1 from the catalyst 21 and the radiation H11 reflected by the under cover 3 enter this end portion 41.

[0019] However, in the present embodiment, at least a part of the facing surface 3a of the under cover 3 is covered with a low-reflectivity material that has a lower reflectivity of radiation than the metal constituting the facing surface 3a. Therefore, the radiation H11 due to reflection can be suppressed, and the heat (hereinafter also referred to as reflected heat) transmitted when the radiation H11 enters can be reduced.

[0020] For example, if the entire facing surface 3a is covered with a low-reflectivity material and the low-reflectivity material is black and has a reflectivity of zero (0) or close to zero, the radiation H11 from the facing surface 3a can be made zero or close to zero. Thereby, the temperature rise of the end portion 41 can be suppressed, and the end portion 41 can be prevented from becoming high temperature.

[0021] Figures 4 and 5 are schematic cross-sectional views showing configuration examples 1 and 2 of the undercover 3 according to the present invention. As shown in Figure 4, the undercover 3 is entirely made of metal, including the opposing surface 3a that faces the catalyst, which is a heat source. A low-reflectance material 31, which has a lower reflectance of radiation than the metal, is provided over the entire opposing surface 3a (e.g., the top surface) of the metal undercover 3. The low-reflectance material 31 is, for example, a heat-resistant paint layer or a colored layer made by cationic coating. From the viewpoint of suppressing the reflectance of radiation H1 (i.e., suppressing radiation H11), the colored layer is preferably an opaque layer, more preferably a dark-colored layer, and even more preferably a black layer.

[0022] The under cover 3 may not be entirely made of metal, but only a portion of it, including the opposing surface 3a. For example, as shown in Figure 5, the under cover 3 may consist of a resin substrate 32 and a metal substrate 33 mounted on the resin substrate 32. The surface of the metal substrate 33 is the opposing surface 3a, and a low-reflectivity material 31 is provided over the entire area of ​​the opposing surface 3a. Even with this configuration, the reflectivity of the radiated heat H1 can be suppressed, similar to the configuration shown in Figure 4.

[0023] Figure 6 is a cross-sectional view obtained by cutting Figure 2 along the line BB', which is parallel to the vehicle's longitudinal direction and passes through the under cover 3. As shown in Figure 6, in this embodiment, the catalyst 21, which is the heat source, the under cover 3, which is the radiation reflector, and the floor under cover 4, which is a resin part, overlap in the vehicle's longitudinal direction. This layout is the closest to the resin part, and the resin part is prone to becoming very hot. However, even with this layout, the opposing surface 3a of the under cover 3 is covered with a low-reflectivity material 31 (for example, a heat-resistant paint layer or colored black by cationic coating), as shown in Figure 4 or Figure 5, so that radiation H11 can be suppressed. This reduces the reflected heat transmitted to the resin part and suppresses the temperature rise of the resin part due to reflected heat.

[0024] Figure 7 is a magnified view of the underbody structure shown in Figure 6, specifically the underbody cover 3 and its surrounding area. As shown in Figure 7, the underbody cover 3 may be positioned only in front of the center of the catalyst 21, which serves as a heat source, in the longitudinal direction of the vehicle. In Figure 7, reference numeral 3RE indicates the rear end of the underbody cover 3 in the longitudinal direction of the vehicle, and reference numeral 4FE indicates the front end of the floor underbody cover 4 in the longitudinal direction of the vehicle. Furthermore, the cross-sectional shape of the underbody cover 3 in a side view of the vehicle may include irregularities (beads).

[0025] As shown in Figure 7, even if the distance from the heat source catalyst 21 to the reflector undercover 3 appears to be large, if a bead is present at a position opposite the heat source (i.e., the position where the radiation H1 is incident), the recess 35 of this bead may concentrate the reflected heat like a concave mirror. However, even in this configuration, the opposing surface 3a of the undercover 3, including the recess 35 of the bead, is covered with a low-reflectivity material 31 as shown in Figures 4 and 5, so the concentration of reflected heat can be suppressed.

[0026] Figure 8 is an example diagram showing the underbody of the vehicle shown in Figure 2 with the under cover 3 removed. Figure 9 is a magnified view of the connection point between the catalyst 21 and the harness 71 shown in Figure 8 and its vicinity. As shown in Figure 8, the area facing the under cover 3 under the vehicle floor is where, for example, the harness 71 and connector 72 of the exhaust temperature sensor 7 are arranged. In this embodiment, in addition to (or instead of) the floor under cover 4, the harness 71 including a resin coating and the connector 72 including a resin exterior (housing) may be the "resin parts" of the present invention. Even in this embodiment, since the opposing surface 3a of the under cover 3 is covered with a low-reflectivity material 31, radiation H11 to the harness 71 and connector 72 can be suppressed, and the temperature rise of these can be suppressed.

[0027] Furthermore, as shown in Figure 9, the harness 71 has a metal pipe 711 and wiring 712 covered with a resin coating, and a portion of the wiring 712 may be passed inside the pipe 711. In this case, not only the wiring 712 located outside the pipe 711 but also the wiring 712 located inside the pipe 711 may be included in the "resin component" of the present invention. By suppressing the radiation H11 to the pipe 711, the temperature rise of the wiring 712 located inside the pipe 711 can be suppressed.

[0028] (Experimental results) The inventors conducted an experiment to investigate the temperature change of a resin floor undercover (hereinafter also referred to as the resin cover) in a vehicle underbody structure. The example described a configuration in which the entire opposing surface of an aluminum tunnel undercover was colored black, while the opposing surface of the aluminum tunnel undercover was not colored at all. The only difference between the example and the comparative example was the presence or absence of coloring on the opposing surface. In this experiment, the vehicle engine was rotated while stationary, and the temperature of the resin cover was measured while maintaining this state.

[0029] Figure 10 is a graph showing the experimental results conducted by the inventors. The horizontal axis of Figure 10 shows the elapsed time [seconds] since the engine started rotating, and the vertical axis shows the temperature of the resin cover. In Figure 10, the solid line (1) represents the measurement results of the example, and the dashed line (2) represents the measurement results of the comparative example. As shown in Figure 10, it was confirmed that the temperature rise of the resin cover was suppressed in the example compared to the comparative example.

[0030] (Effects of the embodiment) (1) As described above, the vehicle 1 according to the embodiment of the present invention comprises a catalyst 21 as a heat source located under the vehicle floor, an under cover 3 located under the vehicle floor and covering the catalyst 21 from below, and a resin part (for example, a floor under cover 4) located under the vehicle floor. The resin part is located between the catalyst 21 and the under cover 3 in the vertical direction of the vehicle, and is located on the outside of the vehicle beyond the catalyst 21 in the vehicle width direction. In the under cover 3, the opposing surface 3a facing the catalyst 21 is made of metal, and at least a part of the opposing surface 3a is covered with a low-reflectance material 31 that has a lower reflectivity of radiation than metal. For example, the low-reflectance material 31 is a heat-resistant paint layer, or a colored layer by cationic coating (more specifically, a black layer, a dark-colored layer, or an opaque layer).

[0031] The resin parts receive radiation not only directly from the catalyst 21 but also indirectly from the under cover 3. However, since the opposing surface 3a of the under cover 3 is colored, for example, black, the radiation H11 from the opposing surface 3a can be suppressed, and reflected heat can be reduced. As a result, the temperature rise of the resin parts due to reflected heat can be suppressed not only when the vehicle is in motion but also when the vehicle is stationary and airflow cannot be introduced, thereby preventing the resin parts from becoming overheated.

[0032] (2) Preferably, the under cover 3 does not have through holes for allowing airflow to enter. Even without through holes, the opposing surface 3a of the under cover 3 is colored black or the like to suppress reflection, thereby reducing reflected heat. This makes it possible to suppress the temperature rise of resin parts due to reflected heat, both when the vehicle is in motion and when the vehicle is stationary.

[0033] Since the under cover 3 does not have through holes, it can suppress turbulence in the airflow under the vehicle floor. This reduces air resistance during vehicle operation and improves the aerodynamic performance of the vehicle 1. In addition, since the under cover 3 does not have through holes for air intake, it can prevent flying stones JS from the front tires 6R and 6L from contacting the catalytic converter 21 and other components through through holes. This enhances the protective function of the catalytic converter 21 and other components covered by the under cover 3.

[0034] (3) The catalyst 21 is located in the center tunnel 23 under the vehicle floor and is also provided in part of the exhaust pipe 2 (for example, connected to one end of the exhaust pipe 2), and is configured to have a larger diameter and relatively larger heat capacity than the exhaust pipe 2. The under cover 3 extends across the center tunnel 23 in the vehicle width direction. The resin parts are located on the outside of the vehicle beyond the center tunnel 23 in the vehicle width direction. This layout makes it easy for reflected heat to be transferred to the resin parts via the under cover, even when the resin parts are located far from the heat source. However, even with this layout, the opposing surface 3a of the under cover 3 is colored black or the like to suppress reflection, thereby reducing reflected heat and thus suppressing the temperature rise of the resin parts due to reflected heat.

[0035] (4) The catalyst 21, under cover 3, and resin parts (for example, floor under cover 4) have an overlapping section OLA (see Figure 6) that overlaps in the longitudinal direction of the vehicle. In this layout, the distance from the opposing surfaces 3a of the catalyst 21, which is a heat source, and the under cover 3, which is a reflector, to the resin parts is the shortest, making it easy for the temperature of the resin parts to become high. However, even with this layout, the opposing surface 3a of the under cover 3 is colored black or the like to suppress reflection, and thus the reflected heat can be reduced, thereby suppressing the temperature rise of the resin parts due to reflected heat.

[0036] (5) The catalyst 21 is provided in a part of the exhaust pipe 2. The resin component has a floor under cover 4 which extends in the longitudinal direction of the vehicle, located outside the exhaust pipe 2 in the vehicle width direction, and is positioned away from the floor panel 8. The floor under cover 4 has an arm portion 42 (see Figure 3) for fixing to the floor panel 8. The arm portion 42 is located in the overlap portion OLA.

[0037] In this layout as well, the opposing surface 3a of the under cover 3 is colored black or the like to suppress reflection, thereby reducing reflected heat and thus suppressing the temperature rise of the arm portion 42 due to reflected heat. For example, even if the floor under cover 4, including the arm portion 42, is constructed from inexpensive materials with not very high heat resistance, such as polypropylene (PP) or polyethylene terephthalate (PET), it becomes possible to position the arm portion 42 closer to the heat source, and the parts of the floor under cover 4 other than the arm portion 42 can also be extended toward the heat source. This makes it possible to increase the area of ​​the floor under cover 4 and improve the aerodynamic performance of the vehicle.

[0038] (6) The under cover 3 may be positioned only in front of the center of the catalyst 21 in the longitudinal direction of the vehicle. The cross-sectional shape of the under cover 3 in a side view of the vehicle may include irregularities (beads). The under cover 3 can have its mechanical strength further increased by having beads. In addition, it is preferable that the opposing surface 3a of the under cover 3, including the recesses 35 of the beads, be colored black or the like. This makes it possible to suppress the concentration of reflected heat due to the recesses 35. It is possible to achieve both improved mechanical strength of the under cover 3 and suppression of the concentration of reflected heat.

[0039] (7) The catalyst 21 may be a GPF. The resin part may have at least one of the harness 71 and connector 72 of the exhaust temperature sensor 7 for the GPF. Even in this configuration, the under cover 3, whose opposing surface 3a is colored black or the like, can suppress the temperature rise of the harness 71 and connector 72, thereby preventing these parts from becoming hot. In addition, the exhaust temperature sensor 7 can be protected from flying stones JS (see Figure 1).

[0040] (8) As shown in Figure 4, the under cover 3 may be made entirely of metal, including the opposing surface 3a. By using a heat-resistant metal, the under cover 3 can be positioned closer to the catalyst 21, and the area of ​​the under cover 3 can be increased. This improves aerodynamic performance. Increasing the area of ​​the under cover 3 also increases the area of ​​the opposing surface 3a (radiation reflecting surface) that faces the heat source. However, the opposing surface 3a can be colored, for example, black, to suppress reflection, thereby suppressing the temperature rise of the resin parts due to reflected heat. This makes it possible to achieve both improved aerodynamic performance and suppression of the temperature rise of the resin parts.

[0041] (9) An under cover 3 according to an embodiment of the present invention is an under cover for a vehicle that is attached to the underside of the vehicle floor and covers a heat source (for example, a catalyst 21) located under the vehicle floor from below, wherein the opposing surface 3a facing the heat source is made of metal, and at least a part of the opposing surface 3a is covered with a low-reflectance material 31 which has a lower reflectivity of radiation than metal. With this, the same effect as in (1) above can be obtained.

[0042] (Other embodiments) As described above, the present invention has been described by embodiments, but the descriptions and drawings that constitute part of this disclosure should not be understood as limiting the present invention. Various alternative embodiments and modifications will become apparent to those skilled in the art from this disclosure. For example, the low-reflectivity material 31 shown in Figure 4 or Figure 5 may be provided not over the entire surface 3a, but only in a portion of the surface 3a. For example, instead of coloring the entire surface 3a of the under cover 3 black, only a portion of the surface 3a may be colored black. If the surface 3a of the under cover 3 has a bead, only a portion of the surface 3a including the recess 35 of the bead may be colored black. Even in such embodiments, reflection can be suppressed in the area of ​​the surface 3a that is colored black, so that reflected heat can be reduced to some extent.

[0043] Thus, this technology naturally includes various embodiments not described herein. Within the scope of the embodiments described above, at least one of various omissions, substitutions, and modifications of the components can be made. Furthermore, the effects described herein are merely illustrative and not limiting, and other effects may also exist. [Explanation of Symbols]

[0044] 1...Vehicle, 2...Exhaust pipe, 3...Under cover, 3a...Opposite surface, 3FE...Front end, 3RE...Rear end, 3SE...Both left and right ends, 4...Floor under cover, 4FE...Front end, 5...Front under cover, 6L...Left front tire, 6R...Right front tire, 7...Exhaust temperature sensor, 8...Floor panel, 21...Catalytic converter, 23...Center tunnel, 24...Heat shielding layer, 31...Low reflectivity material, 32...Resin substrate, 33...Metal substrate, 35...Recess, 39...Fastening member, 41...End, 42...Arm section, 51...Suspension member, 71...Harness, 72...Connector, 711...Piping, 712...Wiring, H1...Radiation (from heat source), H11...Radiation (by reflection), JS...Stone chip, OLA...Overlap section

Claims

1. The heat source located under the vehicle floor, A first under cover located beneath the vehicle floor and covering the heat source from below, The vehicle comprises a resin component located under the vehicle floor, The resin component is located between the heat source and the first under cover in the vehicle's vertical direction, and is located outside the vehicle beyond the heat source in the vehicle's width direction. In the first undercover, A vehicle in which the opposing surface facing the heat source is made of metal, and at least a portion of the opposing surface is covered with a low-reflectance material that has a lower radiant reflectance than the metal.

2. The vehicle according to claim 1, wherein the low-reflectance material is a heat-resistant paint layer, or a black layer, dark-colored layer, or opaque layer formed by cationic coating.

3. The vehicle according to claim 1 or 2, wherein the first under cover is not provided with through holes for allowing airflow during driving.

4. The heat source is located in the tunnel beneath the vehicle floor and is also provided in a part of the exhaust pipe, and is configured to have a larger diameter and relatively larger heat capacity than the exhaust pipe. The first under cover extends in the vehicle width direction so as to straddle the tunnel, The vehicle according to claim 1 or 2, wherein the resin part is located on the outside of the vehicle beyond the tunnel in the vehicle width direction.

5. The vehicle according to claim 1 or 2, wherein the heat source, the first under cover, and the resin part have overlapping portions that overlap in the front-rear direction of the vehicle.

6. The heat source is provided in a part of the exhaust pipe, The aforementioned resin component has a second under cover that extends in the vehicle longitudinal direction, positioned outside the vehicle in the vehicle width direction, beyond the exhaust pipe, and spaced apart from the vehicle floor. The second under cover has an extension for being fixed to the vehicle floor surface, The vehicle according to claim 5, wherein the extension portion is located in the overlap portion.

7. The first under cover is positioned only in front of the center of the heat source in the vehicle's longitudinal direction. The vehicle according to claim 1 or 2, wherein the cross-sectional shape of the first under cover in a side view of the vehicle includes irregularities.

8. The heat source is a GPF, The vehicle according to claim 1 or 2, wherein the resin component has at least one of the connector and harness for the exhaust temperature sensor for the GPF.

9. The vehicle according to claim 1 or 2, wherein the first under cover is entirely made of the metal, including the opposing surface.

10. An under cover that is attached to the underside of a vehicle and covers a heat source located under the vehicle from below, An underbody cover for a vehicle, wherein the opposing surface facing the heat source is made of metal, and at least a portion of the opposing surface is covered with a low-reflectance material that has a lower radiant reflectivity than the metal.

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