JP7657532B2 - Air guide structure on the underside of the front of the vehicle - Google Patents

Description

The present invention relates to an air guide structure for the underside of the front of a vehicle.

In order to prevent the wind flowing under the vehicle from entering the engine compartment and deteriorating the aerodynamic characteristics, an air guide structure is known that has fins extending downward from the front of the vehicle, for example, from the lower part of the front bumper (see, for example, Patent Document 1).

With this type of air guide structure, the negative pressure generated behind the fins acts to suck the air in the engine compartment downward, thereby preventing the wind flowing underneath the vehicle from entering the engine compartment.

However, with an air guide structure that only provides the above-mentioned fins, the difference in speed between the wind flowing under the vehicle and the airflow sucked out of the engine compartment is large, so the two do not mix well, resulting in an uneven distribution of the wind speed passing through the rear of the vehicle, which causes a deterioration in the aerodynamic characteristics of the vehicle.

JP 2012-101698 A

The present invention was conceived in light of the above circumstances, and its objective is to provide an air guide structure for the underside of the front of a vehicle that can prevent or reduce the deterioration of aerodynamic characteristics caused by the air flowing underneath the vehicle.

To solve the above problems, the present invention employs the following technical means:

In other words, the air guide structure for the underside of the front of the vehicle provided by the present invention is characterized in that, in a vehicle having a fin extending downward from the lower part of the front bumper, a horizontal wall extending generally in the fore-and-aft direction is provided behind the fin, and a vertical wall is provided that is continuous with the front end of the horizontal wall and extends generally downward.

When the vehicle is traveling at high speed, vortices are generated one after another near the bottom end of the fins extending from the front bumper in a counterclockwise direction when viewed from the right side of the vehicle. Meanwhile, an airflow is generated from the engine compartment flowing along the lower surface of the horizontal wall or the rear surface of the vertical wall, as if sucked out by the negative pressure of the traveling wind flowing under the vehicle, and this airflow further develops the vortexes. As the vortices thus developed fly one after another under the vehicle toward the rear, the traveling wind flowing under the vehicle and the airflow sucked out from the engine compartment mix well, making it possible to reduce the speed difference between the traveling wind flowing under the vehicle and the airflow sucked out from the engine compartment. As a result, the wind speed distribution of the wind passing behind the vehicle is made uniform, and deterioration of the vehicle's aerodynamic characteristics can be prevented or reduced.

Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the drawings.

1 is a schematic vertical cross-sectional view of a front part of a vehicle showing an embodiment of the present invention. FIG. 11 is a schematic vertical cross-sectional view of a front part of a vehicle showing another embodiment of the present invention.

The preferred embodiment of the present invention will be described in detail below with reference to the drawings.

Figure 1 is a schematic vertical cross-sectional view of the lower front part of a vehicle showing one embodiment of an air guide structure A1 according to the present invention, where the symbol fr indicates the front of the vehicle and the symbol rr indicates the rear of the vehicle.

A grille opening 21 is provided in the front of the vehicle, for example in the front bumper 2, and an air conditioner condenser 4, a radiator 5, and a radiator fan 6 are arranged in this order in the engine room 3 behind the grille opening 21. Further behind the radiator fan 6, a power unit (not shown) such as a gasoline engine and a transmission is arranged. Reference numeral 51 denotes a radiator lower support that supports the lower part of the radiator 5.

A fin 22 extending downward is provided on the lower part of the front bumper 2. The fin 22 is made of, for example, resin, and is provided over a predetermined area corresponding to the spacing between the side members (not shown) of the vehicle.

In the present invention, a horizontal wall 71 and a vertical wall 72, which will be described below, are provided behind the fin 22 described above.

The horizontal wall 71 is formed in a plate shape that generally extends in the front-rear direction in its cross section. The vertical wall 72 is formed in a plate shape that continues from the front end of the horizontal wall 71 and generally extends downward, but in this embodiment, this vertical wall 72 is formed to include a tapered portion 721 and a vertical portion 722 that continues from this tapered portion 721. Note that this tapered portion 721 may also be a gently curved rounded portion.

Preferably, the distance a between the fin 22 and the vertical wall 72 is equal to the extension length b of the fin 22, and the lower end position of the vertical wall 72 is at the same height as or slightly higher than the lower end position of the fin 22, but this is not limited thereto. Preferably, the vertical height c of the vertical wall 72 is at least half the extension length b of the fin 22, but this is not limited thereto.

In this embodiment, the horizontal wall 71 and the vertical wall 72 are formed from an integral sheet metal member, and the length in the vehicle width direction may be set to a length corresponding to the distance between the left and right side members (not shown), for example. The integral member of the horizontal wall 71 and the vertical wall 72 is supported by the radiator lower support 51 via a stay (not shown). In this embodiment, in order to ensure the rigidity of the horizontal wall 71, a bent portion 711 with a crank-shaped cross section is provided at the rear end of the horizontal wall 71.

Next, we will explain the operation of the air guide structure A1 configured as above.

When the vehicle is traveling at high speed, cooling air flows into the engine compartment 3 from the grill opening 21, and high-speed running wind A blows through the area below the vehicle. At this time, immediately behind the fins 22, an air flow B1 flowing downward from the engine compartment 3 generates a vortex R1 that rotates at a fixed position in a clockwise direction in FIG. 1. Then, due to the rotational force of this vortex R1 and the running wind A below the vehicle, counterclockwise vortices R2 are generated one after another and flow rearward on the running wind A. Meanwhile, an air flow indicated by arrow B2 in FIG. 1 flows largely counterclockwise from the engine compartment along the lower surface of the horizontal wall 71 or the rear surface of the vertical wall 72, as if sucked out by the negative pressure of the running wind A flowing below the vehicle, and this air flow B2 develops the above-mentioned vortex R2 more strongly. The vortex R2 thus developed flies backward under the vehicle one after another, effectively mixing the running wind A flowing under the vehicle with the airflow B2, B2 sucked out of the engine room 3, reducing the speed difference between the running wind A flowing under the vehicle and the airflow B2, B2 sucked out of the engine room 3. As a result, the wind speed distribution of the wind passing through the rear of the vehicle is made uniform, preventing or reducing the deterioration of the vehicle's aerodynamic characteristics.

Figure 2 is a schematic vertical cross-sectional view of the lower front part of a vehicle, showing an air guide structure A2 according to another embodiment of the present invention. In Figure 2, the same reference numerals are used to designate members or parts equivalent to those shown in Figure 1, and descriptions thereof will be omitted below as appropriate.

In this embodiment, a portion of the lower surface 51a of the radiator lower support 51 functions as the horizontal wall 71, and a vertical wall 72 extends downward from the lower surface 51a of the radiator lower support 51.

Even with this configuration, the counterclockwise vortexes R2 that are generated one after another near the lower end of the fin 22 can be strongly developed by the air flow shown by arrow B2 in Figure 2 that flows largely counterclockwise from the engine room 3 along the lower surface of the horizontal wall 71 or the rear surface of the vertical wall 72, and the same effect as that described above for the embodiment shown in Figure 1 can be expected.

Of course, the present invention is not limited to the above-described embodiments, and all modifications within the scope of the claims are included in the scope of the present invention.

A1, A2 Air guide structure 1 Vehicle 2 Front bumper 21 Grill opening 22 Fin 3 Engine room 4 Air conditioner condenser 5 Radiator 51 Radiator lower support 51a Underside 6 Radiator fan 71 Horizontal wall 711 Bending portion 72 Vertical wall 721 Tapered portion 722 Vertical portion A Traveling wind B1 Air flow B2 Air flow B3 Air flow R1 Vortex R2 Vortex

Claims (3)

In a vehicle having a fin extending downward from the lower part of the front bumper,
A horizontal wall extending generally in the front-rear direction and a vertical wall continuing from a front end of the horizontal wall and extending generally downward are provided behind the fin,
An air guide structure for a lower front portion of a vehicle, characterized in that a space communicating from an engine compartment to the underside of the vehicle is provided between the fin and the vertical wall . 2. The air guide structure for the underside of a front portion of a vehicle according to claim 1, wherein the vertical wall has a tapered portion or a gently curved rounded portion continuing to a front end of the horizontal wall, and a vertical portion continuing thereto. 3. The air guide structure for the underside of a front portion of a vehicle according to claim 1, wherein the distance between the fin and the lower end of the vertical wall is equal to the extension length of the fin, and the lower end position of the vertical wall is at the same height as or slightly higher than the lower end position of the fin.

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