Brake control system for an automotive vehicle

An anti-skid control system for an automotive vehicle comprising:

• first means for detecting a wheel r.p.m. to produce a first signal having a value indicative of the wheel r.p.m.;
• second means for calculating an acceleration rate of wheel r.p.m. operative during a period of release of brake pressure in an automotive hydraulic brake system, for calculating said acceleration rate based on variation of said first signal value, and for comparing said acceleration rate with a given threshold to produce a second signal when the acceleration rate becomes equal to or greater than said given threshold;
• third means, responsive to said second signal, for calculating a deceleration inclination based on variation of said first signal value within an interval between occurrences of said second signals and on the length of said interval, and for calculating a target wheel r.p.m. drop based on said deceleration inclination and on time from the occurrence of said second signal, and for calculating a target wheel r.p.m. based on said target wheel r.p.m. drop and said first signal value at the occurrence of said second signal, said third means producing a third signal having a value representative of said target wheel r.p.m.;
• and
• fourth means for comparing said first signal value sequentially input from said first means with said third signal value to release said brake pressure when said first signal value becomes equal to or less than said third signal value, said fourth means resuming application of the brake pressure when said first signal value becomes equal to or greater than said vehicle speed signal value.

A method for controlling application and release of brake pressure to a brake device of each vehicle wheel of an automotive vehicle in order to prevent the vehicle from skidding and thereby minimizing braking distance, comprising the steps of:

• determining a wheel r.p.m. and generating a first signal indicative of the determined wheel r.p.m.;
• detecting an acceleration rate of wheel r.p.m. during release of said brake pressure to produce a second signal when said acceleration rate becomes equal to or greater than a given threshold;
• determining a target wheel r.p.m. responsive to said second signal based on a difference between said first signal value within an interval of occurrence of said second signals and said first signal value at the occurrence of said second signal;
• comparing said target wheel r.p.m. with actual wheel r.p.m. represented by said signal;
• and
• controlling application and release of brake pressure applied to the braking device of each vehicle wheel corresponding to the result of said step of comparing the target wheel r.p.m. and actual wheel r.p.m.