ANTI-LOCK BRAKING SYSTEM — Operation (Cont'd)

SLIP RATIO = (VEHICLE SPEED − WHEEL SPEED) / VEHICLE SPEED • The applied brake condition is expressed by a slip ratio, as shown above. If the slip ratio is in the range from 0.15 to 0.3, the wheel has adequate cornering performance, and also minimum stopping distance can be achieved. • The slip ratio formula indicates the control of wheel speed by the brakes. The Anti-lock Braking System (A.B.S.) controls brake fluid pressure using the slip ratios and locking condition calculations contained in the A.B.S. E.C.U. • To adjust wheel speed so that the optimum slip ratio can be obtained, the ABS must sense wheel speed (through a wheel sensor) and vehicle speed (through the vehicle speed sensor). If the brake is applied, especially in the locked wheel condition, the vehicle speed differs from the wheel speed. • After the wheel speed changes from the vehicle speed due to excessive brake force, the A.B.S. calculates vehicle speed when the reduced wheel speed reaches the minimum.