JPH0551511B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a front side structure of an automobile that improves the aerodynamic characteristics of an automobile, and particularly improves stability when subjected to crosswinds.

[Conventional technology]

When an automobile is hit by a crosswind while driving at high speed, the vehicle body may be swept to the leeward side, or the steering may become unsteady due to corrective steering operations. In addition, when a car passes multiple large vehicles from the leeward side against a crosswind, the crosswind will be intermittent, causing the above-mentioned sway, and requiring steering operation to correct this. becomes. As a means to improve the steering stability of a car when driving at high speed in the face of such crosswinds, the aerodynamic properties of the suspension (suspension, tires) or body (in particular, reducing the yawing moment coefficient _CY and lift coefficient _CL) are ) can be improved. The above yawing moment coefficient C _Y is the coefficient of the moment that rotates the vehicle in the left and right direction,
This occurs when the vehicle is exposed to a crosswind, that is, when the wind is traveling at a yaw angle ψ with respect to the longitudinal center plane of the vehicle. To explain this in detail, as shown in FIG. 12, when the vehicle 1 receives a crosswind and the yaw angle ψ of the traveling wind 2 becomes ψ≠0, the traveling wind 2 At the side left corner portion 3, the airflow is divided into an airflow flowing along the left side of the automobile 1 and an airflow flowing along the front surface and reaching the right side. At this time, the air flows divided into these equal parts have a flow velocity characteristic, and based on this flow velocity difference, a difference in pressure distribution around the body of the automobile 1 occurs as shown in FIG. 11. As can be seen from this figure, generally the left side surface on the windward side of the automobile 1 has positive pressure, and the right side surface on the leeward side has negative pressure. Therefore, due to these pressure differences, a moment is generated in the automobile 1 that causes it to rotate clockwise in the figure, and this coefficient is the yawing moment coefficient _CY . Here, the relationship between the yaw angle ψ and the yawing moment coefficient C _Y varies depending on the shape of the vehicle body, but in general, C _Y has a maximum value near ψ=25°. Such characteristics of C _Y are mainly due to pressure changes (flow velocity changes) on the leeward side, that is, the right corner in the diagram of the automobile 1. That is, on the leeward side of the front side right corner portion 4, the airflow flows along the vehicle body surface,
Even if it peels off, it reattaches immediately, so the flow rate is fast and the negative pressure is large. When the yaw angle exceeds a certain value (generally 25° to 30°), the airflow separates from the car surface at the front side corners, creating more negative pressure than when it flows along the car body surface. becomes smaller. Therefore, it is known that if the corner portion is made angular or its radius of curvature is made small, air flow separation occurs and the yawing moment coefficient C _Y becomes small. By the way, this yawing moment coefficient C _Y
The relationship between C and the air resistance coefficient C _D is that when the radius of curvature _of the front side corner of a car is reduced in order to reduce the yaw moment coefficient _C There is a problem in that it causes negative effects such as increase. On the other hand, the present applicant claims that
According to the No. 1, a turbulence fin that protrudes toward the front of the vehicle body is installed at the front side corner of the vehicle body, at a branch point where the wind from directly in front of the vehicle body is divided into upward and lateral directions. We proposed a front side structure. The front side structure of such an automobile can reduce the yawing moment coefficient C _Y without increasing the air resistance coefficient C _D ;
There is a problem in that the turbulence fins are large. In contrast, the present applicant further argues that
No. 189476 and Utility Model Application Publication No. 61-47779 proposed a structure for the front side part of an automobile that is compact and can reduce the yawing moment coefficient C _Y without increasing the air resistance coefficient C _D.

[Problems to be Solved by the Invention] However, in all of the above-mentioned front side structures of automobiles, since the turbulence fins protrude from the front side, they degrade the appearance of the vehicle and also reduce the yaw angle. There is a problem that the effect of reducing the yaw moment coefficient C _Y is large when the yaw angle is larger than a certain level, and the improvement is small when the yaw angle is small.

[Purpose of the invention]

This invention was made in view of the above problems, and it is possible to improve the yawing moment coefficient without providing a protruding object such as a turbulence fin on the front side part and without increasing the air resistance coefficient C _D.
The purpose of the present invention is to provide a front side structure of an automobile that can reduce C _Y.

[Means to solve the problem]

This invention provides an outer curved surface that is convexly curved outward between the front end surface of the left and right side corners of the front portion of the vehicle body and the side surface of the vehicle body.
Left and right air outlets formed in a substantially vertical slit shape and capable of blowing air in the normal direction of the outer curved surface; crosswind detection means for detecting crosswind applied to the vehicle body; and the left and right air outlets. a control device that drives the fan disposed at the air outlet on the lee side of the crosswind based on an output signal of the crosswind detection means, and a control device that drives the fan disposed at the air outlet on the lee side of the crosswind, based on an output signal of the crosswind detection means. By providing this, the above objective is achieved.

[Action of the invention]

According to this invention, when a crosswind is received, the leeward side is detected, and air is forcibly blown out by a fan from the air outlet formed in the leeward side corner, thereby air is removed from the side corner. Promote flow separation and reduce the yawing moment coefficient when the vehicle is exposed to a crosswind, and when the vehicle is not exposed to a crosswind, do not disturb the flow at the front corner and do not increase the air resistance coefficient C _D .

【Example】

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, as shown in FIGS. 1 to 3, left and right side corner portions 12A,
A vertical slit is formed in the outer curved surface 11C that curves convexly outward between the vehicle body front end surface 11A and the vehicle body side surface 11B of the vehicle body 12B, and air is blown in the normal direction of the outer curved surface 11C. Air outlet 1
4A and 14B, and detects the direction of the crosswind applied to the vehicle body;
Fans 6A and 6B are arranged at the left and right air outlets 14A and 14B to forcibly blow out air from the air outlets 14A and 14B, and based on the output signal of the crosswind detection means 5, the crosswind is detected. A control device 7 for driving a fan 6A or 6B disposed at the air outlet 14A or 14B on the leeward side is provided. The front balance panel 12 in which the air outlets 14A and 14B are formed has an opening 13 formed at the center in the vehicle width direction and adjacent to the lower side of the front bumper 16, and the side corner portions are As shown in FIGS. 2 and 3, it is a hollow member forming a duct 17, and the opening 1
An air intake port 17A is provided at a position facing 3. The fans 6A and 6B are arranged within the doubt 17. The air outlet ports 14A and 14B are connected to the duct 17.
It is formed in a vertically long slit shape at a position opposite to the air intake port 17A. Reference numbers 18A and 18B in the figure are front panels, 1
Front side corner of 9A, 19B body, 2
0 indicates the roof, and 21 indicates the underside of the vehicle body. The cross wind detection means 5 includes a pair of left and right pressure sensors 2 installed near the front ends of the left and right side doors 22.
4A and 24B. The control device 7 also controls the pressure sensors 24A, 2.
From the difference in the pressure applied to the fan 4B, the leeward side when the automobile 10 receives a crosswind is detected, and the motors 26A and 26 of the fan 6A or 6B are activated depending on the pressure difference.
It is composed of a computer, a pressure transducer, etc., which are adapted to drive the motor B. Here, the control device 7 adjusts the voltage V of the current for driving the motors 26A, 26B of the fans 6A, 6B in proportion to the difference ΔP between the sensor outputs P _A and P _B of the pair of pressure sensors 24A, 24B. Being in control. If P _A - P = ΔP is positive and larger than the set value k, it is determined that the crosswind is coming from the right front, and the fan 6B on the leeward side is driven, and P _A - P _B is If it is smaller than -k, it is determined that there is a crosswind coming from the left front, and the fan 6A on the opposite side is driven. That is, the voltages of the motors 26A, 26B of the fans 6A, 6B having the characteristics shown in FIG.
It is controlled by a control device 7. Reference numeral 28 in FIG. 1 indicates a control line connecting the motors 26A, 26B and the control device 7. Next, the operation of the above embodiment will be explained. For example, when the car 10 receives a crosswind from the right front while driving, a pressure difference occurs between the left and right sides of the car body, which is detected by the pressure sensors 24A and 24B.
When the pressure sensor outputs are P _A and P _B , P _A
-P _B =ΔP>k, the control device 7 determines that there is a crosswind coming from the front right, drives the motor 26B of the left fan 6B, and adjusts the motor voltage V based on the characteristics shown in FIG. It is controlled in proportion to the differential pressure ΔP. If there is a crosswind coming from the front right, the third
As shown in the figure, the airflow flowing from the windward side along the front balance panel 12 of the automobile 10 to the leeward side of the vehicle body is caused by the airflow forcedly blown out from the air outlet 14 by the fan 6B. As a result, separation occurs from the vehicle body surface and the air flow rate decreases, resulting in a decrease in negative pressure in this area. Therefore, due to separation of the airflow from the vehicle body surface, the yawing moment coefficient C _Y due to the pressure difference applied to the left and right side surfaces of the vehicle 10 is reduced. Here, the air to be blown out from the air outlet 14B is taken in from the opening 13 formed in the center of the front balance panel 12 while the automobile 10 is running in a crosswind, and is taken in through the air intake 17A and the duct 17. The air is supplied to the air outlet 14B through the air outlet 14B. When the automobile 10 is driven without a crosswind, the fans 6A and 6B are stopped and air is blown out from the opening 13, through the air intake port 17A and the duct 17, and from the air outlets 14A and 14B. Since the flow rate is very small because the fans 6A and 6B act as ventilation resistance, there is no separation of the airflow at the corners, and therefore the air resistance coefficient C _D does not increase. In general, even if the structure is as described above and a fan is not provided, the air outlet 14B (1
The difference ΔC _P between the pressure coefficient C _P (out) at 4A) and the pressure coefficient C _P (in) at the air intake port 12B,
The relationship with the yaw angle of the crosswind is as shown in Fig. 5, as the yaw angle increases, ΔC _P , that is, the air outlet 1
When the negative pressure applied to 4B increases and there is no crosswind, ΔC _P becomes minimum, and the strength of the air blown out from the air outlet 14 is automatically adjusted according to the yaw angle of the crosswind applied to the car 10. will be done. As a result of experiments conducted by the present inventor in the case where no fan is provided, the effect of reducing the yawing moment coefficient C _Y is shown in FIG. That is, in FIG. 6, the solid line indicates the case where no air outlet is provided as in the present invention, and the broken line indicates the case where the configuration of the above embodiment is not used, and as can be seen from the same figure, the yawing It was possible to reduce the moment coefficient C _Y by 20 to 30%. In addition, when there is no crosswind, the air outlet 14B
Since there was almost no air blowing out from (14A), there was no separation of airflow at the corners, and no deterioration in the air resistance coefficient C _D was observed. Furthermore, if the air outlet is provided on the side surface 11B of the vehicle body behind the outer curved surface 11C of the side corner portion, the negative pressure will hardly change even if the oscillation angle changes, and its value will be small. It was. Furthermore, the air outlet is connected to the corner outer curved surface 11.
In the case where the air was not blown out in the normal direction of C, the separation of the airflow at the corners was weak when traveling in a crosswind. Yawing moment coefficient CY as above
The reduction effect can be obtained if the air outlet is installed in an appropriate device at the side corner of the vehicle, but even if the air outlet cannot be installed at the optimal position due to design requirements, etc. ,
According to the above embodiment, the fans 6A and 6B can forcefully blow out air from the air outlet on the leeward side when a crosswind is received, thus ensuring the yawing moment coefficient C _Y. can be reduced to Moreover, as mentioned above, when there is no crosswind or when the pressure difference ΔP between the left and right sides is smaller than k, not only does the fan 6A or 6B not rotate, but this creates ventilation resistance, so the air outlet 14A, 14B
The blowing of air from the vehicle is further suppressed, and a decrease in the air resistance coefficient C _D when traveling straight is further reliably prevented. Next, a second embodiment of the present invention shown in FIG. 7 will be described. In this second embodiment, the front balance panel 1
The air intake port 27A in the doubt 27 is inclined so that the air flow from the front of the automobile 10 can be easily taken into the doubt 27. In the above embodiment, the air to be blown out from the air outlet 14 is taken into the doubt 27A through the opening 13 formed at the center of the front balance panel 12 in the width direction. For example, as in the third and fourth embodiments of the present invention shown in FIGS. 8 and 9, the air intake ports 37A and 47
A may be provided on the front of the front balance panel 12 (the fan and motor are not shown). Here, the doubt 37 of the third embodiment shown in FIG.
is formed similarly to the first and second embodiments by making the corner portions of the front balance panel 12 hollow. In the fourth embodiment shown in FIG. 9, a duct 47 is formed on the back side of the front balance panel 12 by a separate member. Furthermore, as in the fifth embodiment of the present invention shown in FIG. 10, the air intake port 57A may be formed on the lower surface of the front balance panel 12 (the fan and motor are not shown). Further, in the above embodiment, the air outlet 14 is formed in the front balance panel 12, but
The present invention is not limited to this, but if necessary, the air outlet may be provided within an outer curved surface that curves outward in a convex manner between the front end surface of the vehicle body and the side surface of the vehicle body at the front side corner portion of the automobile 10. Any structure may be used as long as it is formed so as to blow out air in the normal direction of the outer curved surface. Therefore, the air outlets 24A, 24B may be formed in the front panels 18A, 18B of the automobile 10, as in the seventh embodiment of the present invention shown in FIG. In this case, the air intake port 67A is formed in the front panel 18A. Further, in the above embodiment, a pair of pressure sensors 24
A and 24B are used to detect the direction and strength of the crosswind, but the present invention is not limited thereto. Other crosswind detection means may also be used.

【Effect of the invention】

Since the present invention is configured as described above, it is possible to reduce the yawing moment coefficient and improve the crosswind stability of the automobile without providing protrusions such as turbulence fins and without increasing the air resistance coefficient of the automobile. Furthermore, by forcibly blowing air out from the air outlet on the leeward side using a fan when a crosswind is received, the crosswind stability of the vehicle can be improved even if the air outlet is not set at the optimum value. It has the excellent effect of being able to reliably improve the

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the front side structure of an automobile according to the present invention, FIG. 2 is an enlarged perspective view of the main part of the same embodiment, and FIG. FIG. 4 is a characteristic line diagram showing the relationship between the differential pressure detected by the cross wind detection means and the fan drive motor voltage in the same embodiment, and FIG. A diagram showing the relationship between the yaw angle and the differential pressure before and after the air outlet,
FIG. 6 is a diagram showing the effects of the present invention in relation to the yaw angle and moment coefficient, and FIGS.
The figures are sectional views and perspective views showing essential parts of second to sixth embodiments of the present invention, and FIG. 12 is a plan view showing the pressure distribution on the outer surface of the vehicle body when the vehicle is subjected to a crosswind. 5... Cross wind detection means, 6A, 6B... Fan,
7...Control device, 11A...Front end surface of vehicle body, 11B
...Car body side, 11C...Outside curved surface, 14A,
14B...Air outlet, 24A, 24B...Pressure sensor.

Claims (1)

[Claims] 1 A substantially vertical slit is formed within an outer curved surface that is convexly curved outward between the front end surface of the vehicle body and the side surface of the vehicle body at the left and right side corner portions of the front portion of the vehicle body, and the outer curved surface Left and right air outlets that can blow air in the normal direction of the
crosswind detection means for detecting crosswinds applied to the vehicle body; fans disposed at the left and right air outlets for forcibly blowing out air from the air outlets; A front side structure of an automobile comprising a control device for driving a fan disposed at an air outlet on the leeward side of a crosswind.