Undercover

Abstract

To provide an undercover capable of suppressing an increase in air resistance of the underfloor surface of a vehicle and deterioration in steering stability while effectively cooling a component to be cooled.SOLUTION: An undercover 10 disposed below a vehicle in a vehicle vertical direction comprises a duct part 12. The duct part 12 includes a duct front 18 provided forward and below a component 16 to be cooled in a vehicle longitudinal direction and inclined rearward and upward so as to supply air toward the component 16, and a duct rear part 20 that is disposed behind the duct front 18 and that guides the air downward so as to discharge the air having reached the component 16 to the outside of the vehicle. The upper end 20a of the duct rear part 20 is positioned above the upper end 18a of the duct front 18.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an undercover for a vehicle. [Background technology]

[0002] Undercovers are provided under the vehicle to prevent foreign objects from entering the engine compartment while efficiently releasing heat from the engine compartment to the outside. The undercover can also improve aerodynamic characteristics by adjusting the airflow under the floor of the vehicle depending on its structure. For this reason, various technologies related to undercovers have been proposed according to the purpose.

[0003] For example, Patent Document 1 discloses an undercover structure for a vehicle in which an opening is formed at a position rearward of the engine and forward of the suspension frame. In this undercover structure, air that has passed under the engine is discharged from the opening without being blocked by the suspension frame, so that air stagnation in the engine room is suppressed. As a result, it is said that the flow rate of air introduced into the engine room can be increased, improving the cooling performance of the radiator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-47779 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the structure of the lower part of the vehicle where the undercover is arranged has the following problems. First, the faster the flow speed of the air that hits the parts to be cooled in the engine room to cool them, the more effective the cooling. However, since there are various on-board parts in the engine room, the air flow speed generally tends to be slow. In addition, when the air that hits the parts to be cooled is discharged to the outside of the vehicle, the air flow on the underfloor of the vehicle may be disturbed. For example, if the air discharged from the engine room and the air on the underfloor cannot smoothly merge, the air resistance on the underfloor increases, and as a result, the driving stability may deteriorate. In other words, in the structure of the lower part of the vehicle, a structure that can deal with the above problems is desired, taking into consideration both the cooling performance for the parts to be cooled and the aerodynamic performance on the underfloor of the vehicle.

[0006] Therefore, in this specification, an undercover is realized that can effectively cool the parts to be cooled while suppressing an increase in air resistance on the underfloor surface of the vehicle and a deterioration in driving stability. [Means for solving the problem]

[0007] The undercover disclosed in this specification is an undercover that is positioned below the vehicle in the vehicle up-down direction, and is equipped with a duct portion, the duct portion having a front duct portion that is provided forward and below the part to be cooled in the vehicle fore-and-aft direction, and that inclines rearward and upward so that air flows toward the part to be cooled, and a rear duct portion that is located rearward of the front duct portion, and that guides the air downward so that the air that hits the part to be cooled is discharged to the outside of the vehicle, and is characterized in that an upper end of the rear duct portion is located higher than an upper end of the front duct portion. Effect of the Invention

[0008] According to the undercover disclosed in this specification, the air flowing along the upper surface of the front part of the duct, which is inclined rearward and upward, hits the part to be cooled, and the upper end of the rear part of the duct is positioned higher than the front part of the duct, so that the hit air can be guided to flow through the inside of the duct and reliably under the floor. In other words, it is possible to prevent the air that hits the periphery of the part to be cooled from stagnating without being discharged to the outside of the vehicle, and to prevent the air flowing under the floor of the vehicle from flowing back into the duct, so that the part to be cooled can be effectively cooled while suppressing an increase in air resistance on the underfloor of the vehicle. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic perspective view of the undercover as viewed from above and from the front. [Diagram 2] FIG. 2 is a side view showing a schematic view of the undercover and its peripheral members. [Diagram 3] 3 is an enlarged view of a duct portion of the undercover in FIG. 2. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The vehicle undercover will now be described with reference to the drawings. In each drawing, "Fr", "Up" and "Rh" indicate the front, upper and right sides of the vehicle, respectively.

[0011] Fig. 1 is a schematic perspective view of an undercover as viewed from above and from the front. The undercover 10 shown in Fig. 1 is disposed below the vehicle in the vehicle up-down direction. More specifically, the undercover 10 according to the embodiment is disposed below an engine room of the vehicle in which a radiator, an engine (both not shown), and the like are disposed.

[0012] As shown in Fig. 1, the undercover 10 has a duct portion 12 in the approximate center and toward the rear. The duct portion 12 is provided to efficiently direct the air flowing in the engine room to the parts to be cooled and to exhaust the air to the outside of the vehicle. The duct portion 12 has a shape that inclines rearward and upward in the vehicle front-rear direction as a whole, and has fins 14 on its outer side surface in the vehicle width direction. In Fig. 1, the duct portion 12 is shown as a dark portion, and the fins 14 are shown as light-shaded portions.

[0013] As shown in Fig. 1, a part to be cooled 16 is disposed above the duct portion 12. The part to be cooled 16 is, for example, a driving part such as a transmission. Driving parts such as a transmission need to be cooled effectively in order to improve durability. Therefore, in the embodiment, the structure of the undercover 10 allows air to flow toward the part to be cooled 16, so that the part to be cooled 16 can be cooled effectively. The structure will be described in detail later.

[0014] In addition, in FIG. 1, the air flowing in the engine room is represented by two-dot chain arrows. Of the two arrows shown in FIG. 1, one arrow represents the air flowing along the upper surface of the duct section 12 hitting the cooled part 16, and passing through the inside of the duct section 12 (hereinafter also referred to as the "inner surface side"). The other arrow represents the air flowing along the side surface of the duct section 12 and being guided to the rear of the engine room by the fins 14. The fins 14 are not essential elements of the duct section 12. For example, if there is no part to be cooled other than the cooled part 16 at the rear of the duct section 12, the fins 14 do not need to be provided in the duct section 12.

[0015] Next, referring to FIG. 2, the structure of the undercover 10, particularly the duct portion 12, and the air flow around the undercover 10 will be described. FIG. 2 is a side view showing the undercover and its peripheral members. As shown in FIG. 2, a bumper cover 22 attached to the front end of the vehicle is disposed above the undercover 10. In the engine room above the undercover 10, a radiator 24, an oil pan 26, the cooled parts 16, a suspension frame 28, and the like are disposed, for example, from the front side of the vehicle. The radiator 24 and the like are part of the members mounted in the engine room, and various other on-board parts may be present in the engine room. The air introduced from the front grille (not shown) attached to the bumper cover 22 flows toward the rear of the vehicle while hitting each on-board part in the engine room, so the flow rate of the air in the engine room is generally likely to be slow. Therefore, in the structure of the lower part of the vehicle, it is difficult to effectively cool the cooled parts 16 by hitting the air against them unless some measure is taken. Therefore, the undercover 10 is structured as shown below.

[0016] As shown in FIG. 2, the duct section 12 of the undercover 10 has a duct front section 18 and a duct rear section 20 disposed rearward of the duct front section 18. The duct front section 18 has a shape in which its front end is disposed forward and below the cooled component 16, and is inclined rearward and upward. Here, in FIG. 2, the air flow is represented by two-dot chain arrows, and as the upper one of the two arrows indicates, a part of the air flowing through the engine room flows along the upper surface of the duct front section 18 toward the cooled component 16. This is because the duct front section 18 is inclined rearward and upward, so that the air is pushed against the upper surface of the duct front section 18 and guided to climb uphill. The climbing air then hits the cooled component 16 disposed rearward and above the duct front section 18. As a result, the cooled component 16 is cooled. In this example, the air passing over the upper surface of the duct front portion 18 is introduced toward the part 16 to be cooled, so that the flow rate is faster than the air simply flowing inside the engine compartment. As a result, the part 16 to be cooled can be cooled effectively.

[0017] The air that hits the cooled part 16 then passes through the inner side of the duct part 12 and is discharged to the outside of the vehicle. More specifically, the shape of the duct rear part 20 guides the air that hits the cooled part 16 downward so that the air is discharged to the outside of the vehicle. As shown in FIG. 2 with parts of the duct front part 18 and the duct rear part 20 surrounded by dashed lines, the duct front part 18 has an upper end 18a, and the duct rear part 20 has an upper end 20a. As shown in FIG. 2, the upper end 20a of the duct rear part 20 is positioned higher than the upper end 18a of the duct front part 18. With this configuration, the air that hits the cooled part 16 does not flow behind the cooled part 16 but flows along the inner side of the duct part 12. That is, the upper end 20a of the duct rear part 20 acts like a wall, so that the air that hits the cooled part 16 is guided to flow under the floor through the duct part 12. Here, air flowing rearward along the underside of the vehicle floor, i.e., the underside of the undercover 10 (travel wind represented by the lower arrow among the two-dot chain arrows in FIG. 2) generates negative pressure in the lower part of the duct portion 12. Due to the generation of this negative pressure and the shape of the duct portion 12 in which the upper end 20a of the duct rear portion 20 is located higher than the upper end 18a of the duct front portion 18, the air that hits the cooled part 16 is drawn to the lower part of the duct portion 12 and is easily discharged through the inner surface of the duct portion 12 to the outside of the vehicle.

[0018] Next, the shape of the lower end of the duct portion 12 will be described with reference to FIG. 3. FIG. 3 is an enlarged view of the duct portion of the undercover of FIG. 2. As shown in part A surrounded by a dashed line in FIG. 3, the lower end of the duct front portion 18 has a protruding shape. Specifically, the undercover 10 has a generally substantially flat shape except for the substantially central portion where the duct portion 12 is provided, but a protruding portion is formed below the portion immediately before the portion where the duct portion 12 is provided (in other words, the front end portion of the duct portion 12). This protruding portion (i.e., the protruding shape) causes the air flowing rearward along the lower surface of the undercover 10 to deflect downward. Therefore, it is possible to prevent the air on the lower surface of the undercover 10 from flowing back into the duct portion 12 or interfering with the air discharged from the duct portion 12. As a result, the amount of air discharged from the duct portion 12 increases, so that the amount of air stagnating in the engine room can be reduced and the flow speed is increased. In addition, the air flowing along the lower surface of the undercover 10 and the air discharged from the duct portion 12 can be smoothly joined at the lower portion of the duct portion 12.

[0019] FIG. 3 further shows an enlarged view of the lower end portion of the duct rear portion 20, surrounded by a two-dot chain line, as part B. As shown in the enlarged view of part B, a folded surface is set at the lower end portion of the duct rear portion 20. More specifically, as shown in two parts C surrounded by a dashed line, the lower end portion of the duct rear portion 20 is provided with folded parts at these two places to form folded surfaces. In this example, the folded surface is set at 45 degrees. For ease of viewing, the folded parts and folded surfaces are shown as dark black parts in FIG. 3. With this configuration, the air discharged from the duct portion 12 flows as a small vortex at this folded surface. In the enlarged view of part B, it is shown as a small vortex W, and the generation of this small vortex W makes it difficult for the air discharged from the duct portion 12 to separate from the undercover 10. That is, in the enlarged view of the B portion, the air flow is indicated by two two-dot chain lines, and the arrow on the side away from the undercover 10 has a cross (indicated as "x" in the drawing), so that the air is less likely to flow in the direction of the cross. That is, the air discharged from the duct portion 12 flows along the undercover 10 without peeling off from the undercover 10. Therefore, the air discharged from the duct portion 12 is prevented from disturbing the flow of the air (i.e., the running wind) that was originally flowing rearward along the undercover 10's undersurface. The above-described structure of the undercover 10 can suppress an increase in air resistance on the underfloor surface and the associated deterioration in steering stability that may occur when the air discharged from the engine room and the air on the underfloor surface cannot smoothly merge, thereby contributing to improved aerodynamic performance.

[0020] Note that the above description is merely an example, and the undercover disclosed in this specification may have a duct portion having a front duct portion provided forward and below the part to be cooled, the front duct portion being inclined rearward and upward, and a rear duct portion disposed rearward of the front duct portion, which guides air downward, and in which the upper end of the rear duct portion is located higher than the upper end of the front duct portion. Note that the front duct portion being forward of the part to be cooled does not necessarily mean being located strictly forward, but may be located relatively forward. Therefore, other configurations may be changed as appropriate.

[0021] For example, as described above, fins may be provided on the side surface of the duct portion only when another cooled part is disposed further rearward of the cooled part and the other cooled part needs to be cooled. In general, in an engine room, it is preferable in terms of aerodynamic performance to discharge air from the duct portion without flowing it rearward. Therefore, whether or not fins are provided on the side surface of the duct portion may be changed depending on the number and positions of the cooled parts in the engine room of the vehicle.

[0022] In the embodiment, the duct portion is provided in the approximate center and toward the rear of the undercover, but a NACA duct or the like may be added in front of the duct portion. In FIG. 1, the NACA duct is indicated by a dashed line and is indicated by reference number 30. In this case, the air introduced from under the floor of the vehicle into the engine room through the NACA duct 30 may be directed toward the duct portion. With this configuration, the flow rate of the air introduced into the engine room can be increased to more effectively cool the parts to be cooled, while the air that hits the parts to be cooled can be discharged from the duct portion.

[0023] Furthermore, as shown by the solid line in Fig. 2, the upper end 18a of the duct front part 18 in the embodiment extends in a straight line rearward and upward, but the upper end 18a may be bent forward. In Fig. 2, the shape of the upper end 18a bent forward is shown by the light-shaded part. With this configuration, a protrusion is formed at the upper end of the upper surface of the duct front part 18, so that the air that is pressed against the upper surface of the duct front part 18 and climbs uphill is blown upward by the protrusion. With this configuration, it is possible to make adjustments such as directing the air toward a specific part of the part to be cooled (i.e., to blow it upward), and the cooling performance for the part to be cooled can be further improved. [Explanation of symbols]

[0024] 10 undercover, 12 duct portion, 14 fin, 16 cooled part, 18 duct front portion, 18a upper end of duct front portion, 20 duct rear portion, 20a upper end of duct rear portion 20, 22 bumper cover, 24 radiator, 26 oil pan, 28 suspension frame.

Claims

[Claim 1] An undercover that is disposed under a vehicle in a vehicle up-down direction, Equipped with a duct section, The duct portion is a duct front portion provided forward and below the part to be cooled in the vehicle front-rear direction, the duct front portion inclined rearward and upward so that air flows toward the part to be cooled; a duct rear portion disposed rearward of the duct front portion, the duct rear portion guiding the air downward so that the air that hits the cooled component is discharged to the outside of the vehicle; having The upper end of the rear portion of the duct is located higher than the upper end of the front portion of the duct. An undercover characterized by:

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