JP7506989B2 - Vehicles with improved aerodynamics - Google Patents

Description

The present invention relates to a vehicle that improves aerodynamic characteristics.

Vehicles such as automobiles have a body (Patent Document 1). Air currents are generated around the moving body. After the air in the direction of travel of the body hits the front of the body, it branches out toward the sides and top of the body, flows along the sides and top of the body, and then joins together at the rear of the body. This air current is one of the factors that impede the movement of the vehicle.

JP 2015-182496 A

For this reason, it is conceivable to give the body of an automobile a streamlined shape, for example. With a streamlined body, the air hitting the front of the body can be redirected and directed toward the sides and top of the body without being stopped, and the airflow can merge behind the body without forming vortexes. This can provide a certain degree of improvement in the aerodynamic characteristics of the vehicle.

An air dam forming member that protrudes downward from the underside of the front is provided to reduce the amount of airflow flowing under the vehicle body and improve the CD value. However, by having the air dam forming member protrude from the outer surface of the vehicle body, the airflow becomes turbulent as it passes through the air dam forming member, and the airflow that has passed through the air dam forming member flows close to the outer surface of the vehicle body while remaining turbulent. By providing such an air dam forming member, the balance between the above-mentioned improvement and deterioration effects is added up to an improvement, and an improvement effect can be obtained. Therefore, by reducing the deterioration effects, further aerodynamic improvements can be obtained.

As such, there is a demand for comprehensive improvements to the aerodynamic characteristics of vehicles.

A vehicle having improved aerodynamic characteristics in one embodiment of the present invention is a vehicle having a body capable of travelling, and comprising an air dam forming member protruding from the outer surface of the body so as to extend in a direction intersecting the direction of travel of the travelling vehicle body , and a specially processed surface formed on the outer surface of the body and having a plurality of recesses, the air dam forming member extending along the vehicle width direction of the body on the front underside of the body that is rear of the front bumper of the vehicle, and the specially processed surface is formed on the front underside of the body in an area that is rear of the air dam forming member in the direction of travel, and on the underside portion of the front bumper that is forward of the air dam forming member.

Preferably, the specially machined surface is formed from the area immediately adjacent to the air dam forming member.

Preferably, a flat portion is provided on the underside of the front portion of the vehicle body at a rear portion of the air dam forming member in the direction of travel, and the specially machined surface is formed on the flat portion.

Preferably, the flat portion provided on the underside of the front portion of the vehicle body at a rear portion of the air dam forming member in the traveling direction is inclined so that the rear end in the traveling direction of the vehicle body is lower than the front end.

Preferably, the lower edge of the specially processed surface formed on the inclined flat portion at the rear portion of the air dam forming member in the direction of travel on the underside of the front portion of the vehicle body is located below the lower edge of the air dam forming member.

Preferably, the specially processed surface is formed over the entire surface of the flat portion.

Preferably, the recesses are formed over the entire surface of the specially processed surface.

Preferably, each of the recesses forms a regular polygonal opening or a circular opening in the specially machined surface.

In the vehicle of the present invention, an air dam forming member is provided on the vehicle body to improve the aerodynamic characteristics. The air dam forming member protrudes from the outer surface of the vehicle body so as to extend in a direction intersecting the traveling direction of the traveling vehicle body, and the air flow flowing from the front to the rear of the vehicle body along the traveling direction is suppressed by the air dam forming member. This reduces the amount of air flow passing through the air dam forming member and flowing rearward of the air dam forming member, thereby improving the aerodynamic characteristics.
Moreover, in the present invention, a specially processed surface having a plurality of recesses is formed on the outer surface of the vehicle body that is on the rear side of the air dam forming member in the traveling direction. A part of the airflow that flows from the front to the rear of the vehicle body along the traveling direction near the specially processed surface having a plurality of recesses generates a minute vortex due to the plurality of recesses formed on the specially processed surface. A turbulent boundary layer is formed near the specially processed surface on which the plurality of recesses are formed. As a result, the airflow that flows away from the outer surface of the vehicle body due to the air dam forming member approaches the specially processed surface and becomes easy to flow along the specially processed surface. The airflow that has passed through the air dam forming member flows along the specially processed surface near the specially processed surface on the rear side of the air dam forming member, so that the airflow reattaches to the outer surface of the vehicle body even on the rear side of the air dam forming member and flows along the outer surface of the vehicle body. In particular, by forming the specially processed surface from a portion immediately behind the air dam forming member, the airflow that has passed through the air dam forming member becomes easy to flow along the outer surface of the vehicle body even immediately after passing through the air dam forming member. The specially processed surface formed on the rear side of the air dam forming member can suppress turbulence in the airflow that has passed through the air dam forming member. The airflow that has passed through the air dam-forming member flows along the outer surface of the vehicle body that is on the rear side of the air dam-forming member in the traveling direction of the vehicle, and as a result, the airflow that flows along the outer surface from which the air dam-forming member protrudes can flow along the outer surface from which the air dam-forming member protrudes in substantially the same way as when the air dam-forming member does not exist.
In this way, the present invention can reduce the amount of airflow flowing rearward of the air dam forming member while suppressing turbulence of the airflow rearward of the air dam forming member, thereby improving the aerodynamic characteristics of the vehicle.

FIG. 1 is a side view of an automobile according to a first embodiment of the present invention. FIG. 2 is a bottom view of the vehicle of FIG. FIG. 3 is an explanatory diagram showing the underside of the front part of the body of the automobile shown in FIG. FIG. 4 is an explanatory diagram of a specially processed surface having a plurality of recesses formed on the front lower surface, which is the outer surface of the vehicle body shown in FIG. FIG. 5 is an explanatory diagram of a specially processed surface having a plurality of recesses formed on the front lower surface of an automobile according to a second embodiment of the present invention. FIG. 6 is an explanatory diagram showing a front underside of a vehicle body according to a modified example of FIG.

The following describes an embodiment of the present invention with reference to the drawings.

[First embodiment]
FIG. 1 is a side view of an automobile 1 according to a first embodiment of the present invention.
Fig. 2 is a bottom view of the automobile 1 in Fig. 1. The automobile 1 is an example of a vehicle.

An automobile 1 shown in Figures 1 and 2 has a vehicle body 2. The automobile 1 is an example of an automobile 1. The automobile 1 can travel forward or backward by manual operation by a passenger or automatic driving. In addition, the automobile 1 can travel in a right front, left front, right rear, or left rear direction by steering.
The vehicle body 2 has a basic shape formed by combining a number of boxes, with a front chamber 4 protruding in front of a passenger compartment 3 for accommodating an engine and auxiliary equipment.

An air current is generated around the traveling vehicle body 2. The air in the traveling direction of the vehicle body 2 hits the front surface of the vehicle body 2, then branches toward the side and top surfaces of the vehicle body 2, flows along the side and top surfaces of the vehicle body 2, and joins together at the rear of the vehicle body 2. This air current is one of the factors that hinders the traveling of the automobile 1.
For this reason, it is conceivable that the vehicle body 2 of the automobile 1 is formed, for example, in a shape following a streamlined shape. In the streamlined vehicle body 2, the air that hits the front of the vehicle body 2 can be changed in direction without being stopped and can flow toward the side and upper surface of the vehicle body 2, and can be merged behind the vehicle body 2 without forming a vortex of the air flow. As a result, the automobile 1 can obtain a certain improvement effect of the aerodynamic characteristics. For example, an air dam forming member that protrudes downward from the lower surface of the front part is provided to reduce the amount of air flow flowing under the vehicle body and improve the CD value. However, by protruding the air dam forming member from the outer surface of the vehicle body, the air flow becomes turbulent when passing through the air dam forming member, and the air flow that has passed through the air dam forming member flows near the outer surface of the vehicle body while remaining turbulent. By providing such an air dam forming member, the balance between the above-mentioned improvement and deterioration effects is added up to an improvement, and an improvement effect can be obtained. Therefore, by reducing the deterioration effect, a further improvement in aerodynamics can be obtained.

Figure 3 is an explanatory diagram showing the underside of the front of the body 2 of the automobile 1 in Figure 1.

The vehicle body 2 in Fig. 3 is provided with a lower plate 6 on the rear side of the front bumper 5. The lower plate 6 is provided in the lower part of the vehicle body 2, between the front bumper 5 and the lower surface of the passenger compartment 3 so as to cover at least the bottom of the front compartment 4 of the vehicle body 2. The lower plate 6 forms the front lower surface of the vehicle body 2. The lower plate 6 becomes the outer surface of the front lower side of the vehicle body 2.
The lower plate 6 has an inclined plane portion 7 that is inclined so that its rear end in the direction of travel of the vehicle body 2 is lower than its front end, and a horizontal plane portion 8 that extends approximately horizontally from the inclined plane portion 7 rearward along the direction of travel.
An air dam forming member 11 is formed on the front edge of the inclined flat surface portion 7 of the lower plate 6. As a result, the inclined flat surface portion 7 is provided on the front lower surface of the vehicle body 2, in a rear portion of the air dam forming member 11 in the traveling direction.

The air dam forming member 11 is provided at the front edge portion of the lower plate 6 so as to extend in the vehicle width direction, which is the left-right direction of the vehicle body 2. As a result, the air dam forming member 11 protrudes downward from the lower plate 6 on the underside of the front part of the vehicle body 2 so as to extend in a direction intersecting the traveling direction of the vehicle body 2 traveling forward. By having the air dam forming member 11 protrude downward from the lower plate 6 on the underside of the vehicle body 2, the amount of airflow flowing under the vehicle body 2 can be reduced.
The inclined flat surface portion 7 of the lower plate 6 is located to the rear of the air dam forming member 11. The lower edge of the inclined flat surface portion 7, which is inclined at the rear part of the air dam forming member 11 in the traveling direction on the underside of the front part of the vehicle body 2, is located below the lower edge of the air dam forming member 11.

A specially machined surface 20 having a plurality of recesses 21 is formed on the inclined flat surface portion 7 that is provided at an angle on the rear side of the air dam forming member 11. The specially machined surface 20 is formed on the inclined flat surface portion 7 as an inclined flat surface.
The specially processed surface 20 is formed over the entire surface of the inclined plane portion 7, starting from a portion immediately behind the air dam forming member 11. As shown in Fig. 2, the specially processed surface 20 is formed over the entire surface of the front underside of the vehicle body 2 in an area that is rear of the air dam forming member 11 in the traveling direction, with the same width as the air dam forming member 11. The specially processed surface 20 may be formed over the entire surface with a width wider than the air dam forming member 11, for example, with a width corresponding to the vehicle width of the vehicle body 2.
Since the specially processed surface 20 is formed over the entire surface of the inclined flat surface portion 7, the lower edge of the specially processed surface 20 is located below the lower edge of the air dam forming member 11. The airflow that passes through the air dam forming member 11 on the underside of the vehicle body 2 can head toward the specially processed surface 20, which is provided at an angle.

FIG. 4 is an explanatory diagram of a specially processed surface 20 having a plurality of recesses 21 formed on the front lower surface, which is the outer surface of the vehicle body 2 in FIG.
Fig. 4(A) is a front view of the specially machined surface 20. Fig. 4(B) is a schematic cross-sectional view of the specially machined surface 20.

A number of recesses 21 with regular hexagonal openings are formed in a dense arrangement over the entire surface of the specially processed surface 20. The regular hexagonal recesses 21 are arranged in such a way that flat surfaces serving as inclined flat surfaces 7 remain between adjacent regular hexagonal recesses 21.

The inside of the regular hexagonal recess 21 may be formed in the shape of a regular hexagonal prism like the opening, but preferably it is formed in the shape of a concave curved surface or a shape with a trapezoidal cross section as shown in FIG. 4(B). This makes it easier for the airflow flowing into the recess 21 to circulate near the opening of the recess 21. It becomes easier to generate multiple airflows rotating on the specially processed surface 20 between the main flow of the airflow that passed through the air dam forming member 11 on the underside of the vehicle body 2 and the specially processed surface 20. As shown in FIG. 3, the airflow heading toward the specially processed surface 20 generates multiple airflows rotating on the specially processed surface 20 as shown in FIG. 4. By forming multiple recesses 21 on the specially processed surface 20, a turbulent boundary layer 31 with a flow different from the airflow that passed through the air dam forming member 11 is formed near the surface of the specially processed surface 20. A turbulent boundary layer 31 of the same size as the specially processed surface 20 is formed near the surface of the specially processed surface 20.

In this way, a turbulent boundary layer 31 is formed immediately behind the air dam forming member 11, so that the airflow that passes through the air dam forming member 11 flows so as to pass close to the turbulent boundary layer 31, as shown in FIG. 4(B).

As a result, in this embodiment, as shown by the dashed arrow in Fig. 3, the airflow that passes under the air dam forming member 11 flows so as to pass near the inclined plane portion 7 which is the outer surface of the vehicle body 2. The airflow that passes under the air dam forming member 11 reattaches to the inclined plane portion 7 which is the outer surface of the vehicle body 2. In this case, the airflow that flows from near the inclined plane portion 7 to the underside of the horizontal plane portion 8 tries to flow near the horizontal plane portion 8, and can flow along the extension direction of the horizontal plane portion 8 without being disturbed vertically. The airflow that flows under the vehicle body 2 can flow rearward of the vehicle body 2 along the outer surface of the underside of the vehicle body 2, similar to when the air dam forming member 11 is not present.
3, if a turbulent boundary layer 31 is not formed immediately behind the air dam forming member 11, the airflow that passes below the air dam forming member 11 flows at a position away from the inclined flat portion 7, which is the outer surface of the vehicle body 2. In this case, the airflow that flows from near the inclined flat portion 7 to the below of the horizontal flat portion 8 attempts to flow away from the horizontal flat portion 8. In this case, the airflow flowing below the horizontal flat portion 8 becomes a highly turbulent airflow. After the airflow that flows below the vehicle body 2 leaves the vehicle body 2 at the air dam forming member 11, it flows toward the rear of the vehicle body 2 in a highly turbulent state.

As described above, in the automobile 1 of this embodiment, the air dam forming member 11 is provided on the vehicle body 2 in order to improve the aerodynamic characteristics. The air dam forming member 11 protrudes from the outer surface of the vehicle body 2 so as to extend in a direction intersecting the traveling direction of the traveling vehicle body 2, and the airflow flowing from the front to the rear of the vehicle body 2 along the traveling direction is suppressed by the air dam forming member 11. This reduces the amount of airflow that passes through the air dam forming member 11 and flows rearward of the air dam forming member 11, thereby improving the aerodynamic characteristics.
Moreover, in this embodiment, a specially processed surface 20 having a plurality of recesses 21 is formed on the outer surface of the vehicle body 2 on the rear side of the air dam forming member 11 in the traveling direction. A part of the airflow flowing from the front to the rear of the vehicle body 2 along the traveling direction near the specially processed surface 20 having the plurality of recesses 21 generates a minute vortex due to the plurality of recesses 21 formed on the specially processed surface 20. A turbulent boundary layer 31 is formed near the specially processed surface 20 on which the plurality of recesses 21 are formed. As a result, the airflow flowing away from the outer surface of the vehicle body 2 due to the air dam forming member 11 approaches the specially processed surface 20 and is more likely to flow along the specially processed surface 20. The airflow that has passed through the air dam forming member 11 flows along the specially processed surface 20 near the specially processed surface 20 on the rear side of the air dam forming member 11, so that it reattaches to the outer surface of the vehicle body 2 even on the rear side of the air dam forming member 11 and flows along the outer surface of the vehicle body 2. In particular, by forming the specially processed surface 20 from a portion immediately behind the air dam forming member 11, the airflow that has passed through the air dam forming member 11 is more likely to flow along the outer surface of the vehicle body 2 even immediately after passing through the air dam forming member 11. The specially processed surface 20 formed on the rear side of the air dam forming member 11 can suppress turbulence in the airflow that has passed through the air dam forming member 11. The airflow that has passed through the air dam forming member 11 flows along the outer surface of the vehicle body 2 that is rear of the air dam forming member 11 in the traveling direction. As a result, the airflow that flows along the outer surface where the air dam forming member 11 protrudes can flow along the outer surface where the air dam forming member 11 protrudes, approximately in the same way as when the air dam forming member 11 is not present.
In this manner, in this embodiment, the air dam forming member 11 reduces the amount of airflow flowing rearward of the air dam forming member 11 while suppressing turbulence of the airflow rearward of the air dam forming member 11, thereby improving the aerodynamic characteristics of the automobile 1.

Particularly, in this embodiment, the air dam forming member 11 extends along the vehicle width direction of the vehicle body 2 on the underside of the front part of the vehicle body 2. A flat inclined plane portion 7 is provided on the underside of the front part of the vehicle body 2 at a rear portion in the traveling direction of the air dam forming member 11, and the specially processed surface 20 is formed over the entire surface of the flat inclined plane portion 7. Also, the lower edge of the flat inclined plane portion 7 provided on the rear portion in the traveling direction of the air dam forming member 11 on the underside of the front part of the vehicle body 2 is inclined so that the rear end in the traveling direction of the vehicle body 2 is lower than the front end. As a result, the lower edge of the specially processed surface 20 formed over the entire surface of the flat inclined plane portion 7 is located lower than the lower edge of the air dam forming member 11.
In this way, by providing the air dam forming member 11 on the inclined plane portion 7, which is an inclined plane on the underside of the front part of the vehicle body 2, and forming the specially processed surface 20 entirely behind the air dam forming member 11, it is possible to suppress turbulence of the air flow behind the air dam forming member 11 while reducing the amount of air flowing over the underside of the vehicle body 2. In particular, because the lower edge of the specially processed surface 20, which is entirely formed on the inclined plane portion 7, is located lower than the lower edge of the air dam forming member 11, the air flow flowing rearward of the air dam forming member 11 tends to flow as a whole so as to reattach to the outer surface of the vehicle body 2. Turbulence of the air flow flowing rearward of the air dam forming member 11 can be suppressed overall. The air flow flowing rearward of the air dam forming member 11 tends to flow along the underside of the vehicle body 2.

In the above-described embodiment, a plurality of recesses 21 are formed on the specially processed surface 20 .
In contrast, when multiple convex portions are formed on the specially processed surface 20, a turbulent boundary layer 31 is not formed near the surface of the specially processed surface 20. In this case, the airflow that has passed through the air dam-forming member 11 does not flow so as to reattach to the outer surface of the vehicle body 2 behind the air dam-forming member 11. The airflow that has passed through the air dam-forming member 11 flows at a position away from the inclined flat surface portion 7 where the specially processed surface 20 is formed, as shown by the example of the solid arrow in Figure 3. As a result, the airflow that has been disturbed by the air dam-forming member 11 so as to move away from the outer surface of the vehicle body 2 flows under the horizontal flat surface portion 8 while being disturbed up and down.

[Second embodiment]
Next, a vehicle 1 according to a second embodiment of the present invention will be described. In the following description, differences from the above-described embodiment will be mainly described.
The shape of the vehicle body 2 of the automobile 1 according to the second embodiment is similar to that of the above-described embodiment.

FIG. 5 is an explanatory diagram of a specially processed surface 20 having a plurality of recesses 21 formed on the front underside of an automobile 1 according to a second embodiment of the present invention.
Fig. 5(A) is a front view of the specially machined surface 20. Fig. 5(B) is a schematic cross-sectional view of the specially machined surface 20.

On the specially processed surface 20, a plurality of recesses 21 with regular hexagonal openings are formed in a dense arrangement over the entire surface. The regular hexagonal recesses 21 are in contact with other adjacent regular hexagonal recesses 21. In this case, no flat surface portion as the inclined flat surface portion 7 remains between the adjacent regular hexagonal recesses 21. No flat surface portion remains on the specially processed surface 20.

In this embodiment, the airflow rotating above each recess 21 is smaller than the airflow rotating in the above-described embodiment. The thickness of the turbulent boundary layer 31 is thinner than in the above-described embodiment. As a result, the airflow that passes through the air dam forming member 11 flows to pass through a position closer to the specially processed surface 20 than in the above-described embodiment. In addition, since multiple airflows rotate densely above the multiple recesses 21, the turbulent boundary layer 31 can be generated effectively even if it is thin.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications and changes are possible without departing from the gist of the invention.

For example, in the above-described embodiment, the recess 21 formed in the specially processed surface 20 has a regular hexagonal opening. Alternatively, for example, the recess 21 formed in the specially processed surface 20 may have a regular polygonal opening, such as a regular octagonal opening, or a perfect circle opening. By making the opening of the recess 21 a regular polygonal opening or a perfect circle opening in this manner, the vortex flow formed near the opening of the recess 21 can be stabilized.
However, in order to avoid leaving any flat surface portions as the inclined flat surface portions 7 between the adjacent recesses 21, it is preferable to form the openings in the shape of a regular hexagon or a regular rectangle. By avoiding leaving any flat surface portions as the inclined flat surface portions 7, it is possible to reduce the thickness of the turbulent boundary layer 31. In order to allow the airflow to flow smoothly inside the recesses 21, it is preferable to form the inside of the recesses 21 in the shape of a concave curved surface or a shape whose cross section is a trapezoid as shown in FIG. 4(B).

FIG. 6 is an explanatory diagram showing a front underside of a vehicle body according to a modified example of FIG.
6, a specially processed surface 20 having a plurality of recesses 21 is formed on the underside portion of the front bumper 5 extending rearward. In this manner, the underside of the vehicle body which is the front side of the air dam-forming member 11 in the traveling direction of the automobile 1 may also be formed with a specially processed surface 20 having a plurality of recesses 21, similar to the rear side of the air dam-forming member 11. The plurality of recesses 21 on the front side of the air dam-forming member 11 may be the same as or different from the plurality of recesses 21 on the rear side of the air dam-forming member 11.
In this modification, even on the front side of the air dam forming member 11, the airflow heading toward the underside portion of the front bumper 5 tends to generate multiple airflows that rotate on the specially processed surface 20. This makes it easier to form a turbulent boundary layer 31. The airflow flows from front to rear along and near the outer surface of the vehicle body 2 on the front side of the air dam forming member 11. As a result, the effect of the air dam forming member 11 and the straightening effect of the specially processed surface 20 on the rear side of the air dam forming member 11 may be enhanced. The downward protrusion height of the air dam forming member 11 may be reduced.

1 ... automobile (vehicle), 2 ... vehicle body, 3 ... passenger compartment, 4 ... front compartment, 5 ... front bumper, 6 ... lower plate, 7 ... inclined flat portion (outer surface), 8 ... horizontal flat portion (outer surface), 11 ... air dam forming member, 20 ... specially processed surface, 21 ... recess, 31 ... turbulent boundary layer

Claims (8)

A vehicle having a drivable body,
an air dam forming member protruding from an outer surface of the vehicle body so as to extend in a direction intersecting a traveling direction of the vehicle body;
A specially processed surface having a plurality of recesses formed on an outer surface of the vehicle body;
having
The air dam forming member extends along a vehicle width direction of the vehicle body on a front lower surface of the vehicle body rearward of a front bumper of the vehicle,
The specially processed surface is formed on a rear area of the air dam forming member in the traveling direction on the front underside of the vehicle body, and on a lower surface portion of the front bumper which is forward of the air dam forming member.
Vehicles with improved aerodynamics.
The specially processed surface is formed from a portion immediately adjacent to the air dam forming member.
A vehicle having improved aerodynamic characteristics according to claim 1.
A flat portion is provided on a lower surface of a front portion of the vehicle body at a rear portion of the air dam forming member in the traveling direction,
The specially processed surface is formed on the flat surface.
A vehicle having improved aerodynamic characteristics according to claim 2.
the flat portion provided on the lower surface of the front portion of the vehicle body at a rear portion of the air dam forming member in the traveling direction is inclined so that a rear end of the flat portion in the traveling direction of the vehicle body is lower than a front end of the flat portion.
A vehicle having improved aerodynamic characteristics according to claim 3.
a lower edge of the specially processed surface formed on the inclined flat portion at a rear portion of the air dam forming member in the traveling direction on the front underside of the vehicle body is located below a lower edge of the air dam forming member;
A vehicle having improved aerodynamic characteristics according to claim 3 or 4.
The specially processed surface is formed on the entire surface of the flat portion.
A vehicle having improved aerodynamic characteristics according to any one of claims 3 to 5.
The plurality of recesses are formed on the entire surface of the specially processed surface.
A vehicle having improved aerodynamic characteristics according to any one of claims 1 to 6.
Each of the recesses forms a regular polygonal opening or a perfect circle opening in the specially processed surface.
A vehicle having improved aerodynamic characteristics according to any one of claims 1 to 7.

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