Automatic deceleration control method and apparatus for a vehicle

An automatic deceleration control method for automatically decelerating a vehicle in accordance with a turning state of the vehicle, thereby stabilizing turning behavior of the vehicle, comprising the steps of:

• (a) detecting the turning state of the vehicle;
• (b) detecting an actual lateral acceleration generated in the vehicle;
• (c) detecting a friction coefficient of a road surface on which the vehicle is running;
• (d) setting an allowable lateral acceleration at a value which increases with increase in the road friction coefficient when the road friction coefficient falling within a medium or low region is detected in said step (c);
• (e) setting an allowable lateral acceleration while restraining increase of the allowable lateral acceleration when the road friction coefficient falling within a high region is detected in said step (c);
• and
• (f) automatically decelerating the vehicle so as to cause the actual lateral acceleration detected in said step (b) to be equal to or less than the allowable lateral acceleration set in said step (d) or (e) when a turning motion of the vehicle is detected in said step (a).

An automatic deceleration control apparatus for automatically decelerating a vehicle in accordance with a turning state of the vehicle, thereby stabilizing turning behavior of the vehicle, comprising:

• a turning state detecting section for detecting the turning state of the vehicle;
• a friction coefficient detecting section for detecting a friction coefficient of a road surface;
• a deceleration control section operable independently of a driver's braking operation and adapted automatically to decelerate the vehicle so as to cause an actual vehicle speed to be equal to or less than a safe vehicle speed when a turning motion of the vehicle is detected by said turning state detecting section;
• and
• a setting section for setting a safe vehicle speed in accordance with the turning state detected by the turning state detecting section, the setting section being adapted to set the safe vehicle speed at a value which increases with increase in the road friction coefficient when the road friction coefficient falling within a medium or low region is detected by the friction coefficient detecting section and to restrain increase of the safe vehicle speed when the road friction coefficient falling within a high region is detected by said friction coefficient detecting section.

An automatic deceleration control apparatus for automatically decelerating a vehicle in accordance with a turning state of the vehicle, thereby stabilizing turning behavior of the vehicle, comprising:

• a turning state detecting section for detecting the turning state of the vehicle;
• a lateral acceleration detecting section for detecting an actual lateral acceleration generated in the vehicle;
• a friction coefficient detecting section for detecting the friction coefficient of a road surface;
• a deceleration control section operable independently of a driver's braking operation and adapted to decelerate the vehicle so as to cause the actual lateral acceleration to be equal to or less than an allowable lateral acceleration when a turning motion of the vehicle is detected by the turning state detecting section;
• and
• a setting section for setting an allowable lateral acceleration in accordance with the road friction coefficient detected by the friction coefficient detecting section, the setting section being adapted to set the allowable lateral acceleration at a value which increases with increase in the road friction coefficient when the road friction coefficient falling within a medium or low region is detected by said friction coefficient detecting section and to restrain increase of the allowable lateral acceleration when the road friction coefficient falling within a high region is detected by said friction coefficient detecting section.