PURPOSE: To improve the car driving efficiency by maintaining a road surface or a tire surface immediately before the tire earthing, or both the road surface and the tire surface immediately before the tire earthing, by using surface maintaining means, so as to control the friction coefficient and the friction force between the road surface and the tire.
CONSTITUTION: A tire temperature sensor 71, a tire humidity sensor 72, and a tire air pressure sensor 73 are provided to each of four wheels, and an ambiance sensor 11 and a car operation sensor 12 are provided. The values of these sensors are input to an operation condition detecting device 13 together with the detecting values of a steering 8, an accelerator 19, a brake 10, and the like. When a hydroplaining phenomenon is detected, a control unit 14 opens a control valve 30, and closes a control valve 31, so as to blow out the exhaust gas to the front sides of the wheels from a piping 51. And a necessary friction force is inferred by an operation condition detecting sensor, and a control valve 41 is opened and closed to increase and decrease the flow rate. Furthermore, by the operation ambiance data, the blowout direction of an exhaust gas blowout port 51 is controlled with a blowout direction control device 61.
OKA YOSHIE
OKI HIROSHI
ISHII JUNICHI
