Vehicle undercarriage

Abstract

The object is to provide a vehicle underbody structure that can achieve both improved aerodynamic performance and improved cooling performance of the vehicle. [Solution] A vehicle understructure (100) includes a power plant (110) mounted behind a front bumper (104) of a vehicle (102), an undercover (112) extending rearward from the front bumper (104) below the power plant (110), and an air dam (106) extending downward from a range across the vehicle width direction of the lower end of the front bumper (104). The undercover (112) has a front inclined portion (114) extending obliquely rearward and downward from the front bumper (104), and an air intake portion (116) opened in the center of the front inclined portion (114) in the vehicle width direction. The air dam (106) has a cutout (108) that cuts out a predetermined range forward of the air intake portion (116).

Description

[Technical Field]

[0001] The present invention relates to a vehicle underbody structure. [Background technology]

[0002] Air dams are known as components that reduce the air resistance of a vehicle while it is moving. For example, Patent Document 1 describes a fin 10 that is similar to an air dam. In general, providing an air dam reduces the amount of air that enters the underside of the vehicle while it is moving, improving aerodynamic performance and thereby improving fuel efficiency.

[0003] In addition to air dams, undercovers are also known as components with a streamlining effect. For example, Patent Document 2 describes an undercover 10. Generally, undercovers can reduce external vehicle noise and improve aerodynamic performance by covering the area below a power plant such as an engine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-103962 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-180609 Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology of Patent Document 2, a central opening 19 and side openings 20, 22 are provided in an under-cover 10 to introduce wind generated by running the vehicle to cool an engine 24. In particular, as described in paragraph 0016 and Figure 2, the central opening 19 is formed so that wind generated by running the vehicle enters from the underside of the under-cover 10 obliquely upward and rearward.

[0006] However, when the above-mentioned air dam and under cover are installed together, the air dam blocks the air that enters the underside of the vehicle body, which may contradict the cooling effect achieved by the technology of Patent Document 2.

[0007] In view of the above problems, the present invention has an object to provide a vehicle underbody structure that can improve both the aerodynamic performance and the cooling performance of a vehicle. [Means for solving the problem]

[0008] In order to solve the above problems, a typical configuration of a vehicle understructure according to the present invention is a vehicle understructure including a power plant mounted behind the front bumper of the vehicle, an undercover extending rearward from the front bumper below the power plant, and an air dam extending downward from a range spanning the width of the lower end of the front bumper, wherein the undercover has a front inclined portion extending obliquely rearward from the front bumper and an intake portion opened in the center of the front inclined portion in the width direction of the vehicle, and the air dam has a cutout portion cutting out a predetermined range forward of the intake portion. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a vehicle underbody structure that can achieve both improvements in the aerodynamic performance and the cooling performance of a vehicle. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing an outline of a vehicle underbody structure according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram showing a power plant mounting room of the vehicle shown in FIG. [Figure 3] FIG. 3 is a perspective view of the undercover of FIG. 2(b). [Figure 4] FIG. 3 is a cross-sectional view of the vehicle undercarriage structure of FIG. 2(b). [Figure 5] FIG. 3 is a diagram showing other elements in the vehicle undercarriage of FIG. 2(b). [Figure 6]FIG. 2(b) is a diagram showing an analysis of the air flow in the vehicle shown in FIG. 2(a). DETAILED DESCRIPTION OF THE INVENTION

[0011] A vehicle undercarriage structure according to one embodiment of the present invention comprises a power plant mounted behind the front bumper of the vehicle, an undercover extending rearward from the front bumper below the power plant, and an air dam extending downward from a range spanning the width of the lower end of the front bumper, wherein the undercover has a front inclined portion extending obliquely downward and rearward from the front bumper, and an intake portion opened in the center of the front inclined portion in the width direction of the vehicle, and the air dam has a cutout portion cutting out a predetermined range forward of the intake portion.

[0012] According to the above configuration, the cutout portion of the air dam and the intake portion of the undercover allow outside air to be efficiently introduced into the power plant mounting room, making it possible to achieve both improvements in the aerodynamic performance of the vehicle and improvements in the cooling performance within the power plant mounting room.

[0013] The undercover may have a rear inclined portion extending rearward and upward from a position rearward of the power plant, and an exhaust portion opened at a position on the rear inclined portion rearward of the intake portion.

[0014] According to the above configuration, the exhaust portion opened in the rear inclined portion makes it possible to efficiently exhaust air from the power plant mounting room and thereby cool the power plant.

[0015] The vehicle undercarriage may further include a muffler pipe extending rearward from the front of the power plant, across below the power plant, and at least a portion of the muffler pipe may be positioned within the range connecting the intake section and the exhaust section when viewed from above or below.

[0016] According to the above configuration, it is possible to efficiently cool the muffler pipe, which becomes hot during driving.

[0017] At least a portion of the muffler pipe is preferably disposed within a range connecting the intake portion and the exhaust portion when viewed in the vehicle width direction.

[0018] The above configuration also makes it possible to efficiently cool the muffler pipe, which becomes hot during driving.

[0019] The exhaust portion may be wider in the vehicle width direction than the intake portion, and the undercover may further have a connecting portion that spans the exhaust portion in the front-rear direction.

[0020] According to the above configuration, the exhaust section, which is wide in the vehicle width direction, allows for efficient exhaust from the power plant mounting compartment. In addition, the connecting section ensures rigidity around the exhaust section.

[0021] The vehicle undercarriage structure may further include a suspension frame installed behind the power plant and above the undercover, the suspension frame having a central portion in the center of the vehicle width direction and a pair of front legs extending forward and in the vehicle width direction from the left and right ends of the central portion and connected to the undercover, and the exhaust portion may be formed in the range between the pair of front legs.

[0022] The above configuration also makes it possible to ensure the rigidity around the exhaust portion. [Example]

[0023] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in these embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0024] 1A and 1B are diagrams showing an overview of a vehicle underbody structure 100 according to an embodiment of the present invention. Fig. 1A is a diagram showing a front bumper 104 of a vehicle 102 to which the vehicle underbody structure 100 is implemented.

[0025] Hereinafter, in FIG. 1 and all other drawings of the present application, the front-to-rear direction of the vehicle is indicated by arrows F (Forward) and B (Backward), the left and right directions of the vehicle width are indicated by arrows L (Leftward) and R (Rightward), and the up-down direction of the vehicle is indicated by arrows U (Upward) and D (Downward).

[0026] The vehicle undercarriage 100 is configured to include an air dam 106 disposed below a front bumper 104. The air dam 106 is a component that reduces the air resistance of the vehicle 102 while it is traveling. The air dam 106 extends downward from the lower end of the front bumper 104 across the vehicle width.

[0027] In this embodiment, a notch 108 is provided in the center of the air dam 106 in the vehicle width direction. The notch 108 allows air to be introduced from an intake section 116 of an undercover 112 (see FIG. 3(a)).

[0028] Figure 1(b) is an enlarged view of the cutout 108 in Figure 1(a). The cutout 108 is formed by cutting out a predetermined area in front of the intake section 116 of the under-cover 112. The cutout 108 causes the intake section 116 to open toward the front of the vehicle, allowing air to be introduced while driving.

[0029] Fig. 2 is a diagram showing the power plant mounting room R1 of the vehicle 102 of Fig. 1(a). Fig. 2(a) is a diagram showing the power plant mounting room R1 of the vehicle as seen from above.

[0030] The power plant mounting room R1 is an area behind the front bumper 104, and is equipped with a power plant 110 that serves as a power source for the vehicle 102. The power plant 110 includes an engine or a motor, a transmission, and the like.

[0031] 2(b) is a view seen from below of the power plant mounting room R1 of the vehicle 102. The lower side of the power plant 110 is covered by an under cover 112.

[0032] The undercover 112 is a member made mainly of resin, and has a shape that extends rearward from the front bumper 104 across below the power plant 110. The undercover 112 not only prevents the power plant 110 from becoming soiled with mud and the like, but also reduces exterior noise, which is the generation of sound outside the vehicle.

[0033] Fig. 3 is a perspective view of the undercover 112 of Fig. 2(b). Fig. 3(a) is a perspective view of the undercover 112 as seen from the front lower left.

[0034] A front inclined portion 114 is provided on the front side of the undercover 112. The front inclined portion 114 is a portion that extends from the front bumper 104 (see FIG. 4(b)) at an incline downward toward the rear side.

[0035] The intake section 116 is a through-hole provided in the front inclined portion 114, and is opened in the center of the front inclined portion 114 in the vehicle width direction. By being provided in the front inclined portion 114, the intake section 116 is open toward the front of the vehicle. The intake section 116 introduces outside air into the power plant mounting room R1 while the vehicle is running, enabling cooling of the power plant 110.

[0036] 3(b) is a perspective view of the under-cover 112 as seen from the rear lower left. A rear inclined portion 118 is provided on the rear side of the under-cover 112. The rear inclined portion 118 is configured to extend rearward and upward from a position rearward of the power plant 110.

[0037] An exhaust section 120 is provided in the rear inclined section 118. The exhaust section 120 is a through-hole provided in the rear inclined section 118, and is opened at a location located rearward of the intake section 116. By being provided in the rear inclined section 118, the exhaust section 120 is open toward the rear of the vehicle. The exhaust section 120 enables the exhaust of heated air from within the power plant mounting room R1 while the vehicle is running.

[0038] Fig. 4 is a cross-sectional view of the vehicle underbody structure 100 of Fig. 2(b). Fig. 4(a) is a cross-sectional view of the vehicle underbody structure 100 of Fig. 2(b) taken along line AA.

[0039] The AA cross section is shown by cutting the vehicle underbody structure 100 in Fig. 2(b) along a line extending in the vehicle longitudinal direction, and viewed from the left side in the vehicle width direction. In Fig. 4(a), the left side in the drawing is the front of the vehicle, and the upper side in the drawing is the upper side.

[0040] The front of the intake section 116 is open due to the cutout 108 provided in the air dam 106. As described above, the intake section 116 is opened in the front inclined portion 114 of the undercover 112, and is open toward the front of the vehicle. The exhaust section 120 is provided behind the intake section 116, and is opened in the rear inclined portion 118 (see FIG. 3(b)), and is open toward the rear of the vehicle.

[0041] With this vehicle undercarriage structure 100, while the vehicle is traveling, outside air can be efficiently introduced into the power plant mounting room R1 from the intake section 116, thereby cooling the power plant 110. In addition, an exhaust section 120 opened in the rear inclined section 118 (see FIG. 3(b)) makes it possible to efficiently exhaust air from inside the power plant mounting room R1 and thereby cool the power plant 110.

[0042] 4(a), the muffler pipe 122 is illustrated by a broken line. The muffler pipe 122 is a component that discharges exhaust gas from the power plant 110.

[0043] The muffler pipe 122 extends rearward from the front of the power plant 110, passing under the power plant 110. If the power plant 110 is an engine, for example, the muffler pipe 122 guides high-temperature gas discharged from the combustion chamber of the engine to the rear of the vehicle and discharges it.

[0044] Like the power plant 110, the muffler pipe 122 also becomes hot during driving. As the muffler pipe 122 extends from the front of the power plant 110, it is first cooled by outside air taken in through a grill 124 of the front bumper 104. Then, as the muffler pipe 122 extends rearward across below the power plant 110, it is further cooled by air flowing from the intake section 116 of the undercover 112 to the exhaust section 120.

[0045] FIG. 4(b) is an enlarged view of the periphery of the undercover 112 in FIG. 4(a).

[0046] In the vehicle undercarriage structure 100, at least a portion of the muffler pipe 122 is arranged, when viewed from the vehicle width direction, to pass through an area E1 that connects the upper and lower edges of the intake section 116 and the exhaust section 120. This makes it possible to efficiently cool the muffler pipe 122, which becomes hot during driving.

[0047] Figure 5 is a diagram showing other elements in the vehicle underbody structure 100 of Figure 2(b). Figure 5(a) is a diagram showing the muffler pipe 122 through the undercover 112 of Figure 2(b).

[0048] The muffler pipe 122 is arranged within an area E1 that connects the edges of the intake section 116 and the exhaust section 120 in the vehicle width direction, even when viewed from below as shown in FIG. 5(a).

[0049] As described above, the muffler pipe 122 is disposed within an area E1 connecting the intake section 116 and the exhaust section 120 when viewed either in the vehicle width direction shown in Fig. 4 or in the vehicle vertical direction shown in Fig. 5(a). It is known that the temperature of the muffler pipe 122 can become higher than the engine wall surface while the vehicle is running. In this embodiment, the muffler pipe 122 can be exposed to the main flow of outside air flowing from the intake section 116 to the exhaust section 120, making it possible to cool the muffler pipe 122 more efficiently.

[0050] In the vehicle undercarriage structure 100, the exhaust section 120 is located rearward of the intake section 116, but is wider in the vehicle width direction than the intake section 116. This enables the exhaust section 120 to efficiently exhaust air from within the power plant mounting room R1.

[0051] Outside air is introduced into the power plant mounting room R1 not only through the intake section 116 but also through the grille 124 (see FIG. 4(a)). Therefore, by providing the exhaust section 120 wide in the vehicle width direction, it is possible to efficiently exhaust air and dissipate heat from inside the power plant mounting room R1.

[0052] The undercover 112 is provided with a connecting portion 126 that spans the exhaust portion 120 in the front-rear direction. The connecting portion 126 makes it possible to ensure the rigidity of the undercover 112 around the exhaust portion 120.

[0053] The connecting portion 126 can be provided to match the position of a torque rod (not shown) extending from the power plant 110. The torque rod is a member that supports the power plant 110, and is provided to extend rearward from the power plant 110. By providing the connecting portion 126 to match the position of the torque rod, it becomes possible to provide the connecting portion 126 without obstructing the flow of air as much as possible.

[0054] FIG. 5(b) is a diagram showing a suspension frame 128 provided in the vehicle undercarriage 100 of FIG. 2(b).

[0055] The suspension frame 128 is a member that supports the suspension of the front wheels of the vehicle 102, and is installed behind the power plant 110 and above the undercover 112.

[0056] The suspension frame 128 has a central portion 130 located in the center in the vehicle width direction, and a pair of front legs 132, 134 extending from left and right ends of the central portion 130. The front legs 132, 134 extend forward in the vehicle width direction from the left and right ends of the central portion 130. The undercover 112 is fixed to the central portion 130 at connection portions 136a, 136b, and is connected to the front legs 132, 134 at connection portions 136c, 136d.

[0057] The exhaust section 120 is formed on the undercover 112 in an area located between the front legs 132, 134 of the suspension frame 128. By providing the exhaust section 120 within an area connected to the front legs 132, 134 of the highly rigid suspension frame 128, it is possible to ensure the rigidity around the exhaust section 120.

[0058] Fig. 6 is a diagram illustrating an analysis of the air flow of the vehicle 102 in Fig. 2(a). Fig. 6(a) shows, as a comparative example, a conventional vehicle 10 that does not have an air dam 106 (see Fig. 6(b)).

[0059] In the vehicle 10, the color tone is displayed darker in front of the under-cover 112. This indicates that the air flows faster while the vehicle is moving, and that the air resistance of the under-cover 112 is large.

[0060] Figure 6(b) is a diagram analyzing the air flow of the vehicle 102 of this embodiment shown in Figure 2(a). In this embodiment, an air dam 106 is provided in front of the undercover 112. Compared to the vehicle 10 in Figure 6(a), the area in front of the air dam 106 in Figure 6(b) is displayed in a lighter color tone. This means that the air flow is slower while the vehicle is moving, resulting in less air resistance.

[0061] A cutout 108 is provided in the center of the air dam 106, in front of the intake section 116 of the undercover 112. The color tone is darker from the cutout 108 toward the intake section 116, indicating that air is flowing vigorously.

[0062] The color tone around the intake section 116 in FIG. 6(a) is lighter than that of the intake section 116 in FIG. 6(b). This means that the absence of the air dam 106 also affects the efficiency of air introduction. As an example, tests conducted by the inventors have found that the addition of the air dam 106 in FIG. 6(b) increases the flow rate of air flowing into the intake section 116 by approximately 25 percent compared to the conventional configuration in FIG. 6(a).

[0063] As can be seen from these figures, in this embodiment of Figure 6(b), the air dam 106 improves the aerodynamic performance of the vehicle 102, while the cutout 108 and intake section 116 enable outside air to be efficiently introduced into the power plant mounting room R1.

[0064] Furthermore, by providing the cutout 108 and intake section 116 in the center of the vehicle width, the introduced air spreads radially toward the power plant 110 at the rear, making it possible to further improve cooling efficiency.

[0065] As described above, according to this embodiment, the cutout portion 108 of the air dam 106 and the intake portion 116 of the undercover 112 allow outside air to be efficiently introduced into the power plant mounting room R1, thereby making it possible to improve both the aerodynamic performance of the vehicle 102 and the cooling performance within the power plant mounting room R1.

[0066] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Industrial Applicability]

[0067] The present invention can be used in a vehicle underbody structure. [Explanation of symbols]

[0068] 10...vehicle, 100...vehicle undercarriage, 102...vehicle, 104...front bumper, 106...air dam, 108...cutout, 110...power plant, 112...under cover, 114...front inclined portion, 116...intake portion, 118...rear inclined portion, 120...exhaust portion, 122...muffler pipe, 124...grille, 126...connection portion, 128...suspension frame, 130...center portion, 132, 134...front leg, 136a to 136d...connection portion, E1...range, R1...power plant mounting room

Claims

1. A vehicle undercarriage structure including a power plant mounted behind a front bumper of a vehicle, an undercover extending rearward from the front bumper across below the power plant, and an air dam extending downward from a range across the vehicle width direction of a lower end of the front bumper, The undercover is a front inclined portion extending from the front bumper downward and rearward; an intake portion opened at the center of the front inclined portion in the vehicle width direction; and The vehicle undercarriage structure is characterized in that the air dam has a cutout portion formed by cutting out a predetermined area in front of the intake portion.

2. The undercover is a rear inclined portion extending rearward and upward from a position rearward of the power plant; an exhaust portion opened at a position rearward of the intake portion in the rear inclined portion; 2. The vehicle underbody structure according to claim 1, further comprising:

3. The vehicle undercarriage further includes a muffler pipe extending rearward from the front side of the power plant and below the power plant, 3. The vehicle underbody structure according to claim 2, wherein at least a portion of the muffler pipe is disposed within a range connecting the intake portion and the exhaust portion when viewed from above or below.

4. 4. The vehicle undercarriage structure according to claim 3, wherein at least a portion of the muffler pipe is disposed within a range connecting the intake portion and the exhaust portion when viewed in the vehicle width direction.

5. The exhaust section is wider in the vehicle width direction than the intake section, 3. The vehicle underbody structure according to claim 2, wherein the undercover further includes a connecting portion that is bridged across the exhaust portion in the front-rear direction.

6. The vehicle undercarriage further includes a suspension frame disposed rearward of the power plant and above the undercover, The suspension frame is a central portion in the center of the vehicle width direction; a pair of front legs extending forward and in the vehicle width direction from the left and right ends of the central portion and connected to the undercover; 3. The vehicle underbody structure according to claim 2, wherein the exhaust portion is formed in a range between the pair of front leg portions.

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