ABS System Description

Description and operation





The purpose of the antilock brake system is to prevent wheel lockup during periods of high wheel slip. Preventing lockup helps maintain vehicle braking action and steering control. The ABS controller activates the system whenever sensor signals indicate high wheel slip. High wheel slip is a condition where the wheel rotation approaches 20 to 30 percent of actual vehicle speed during braking. This usually occurs when braking involves high pedal pressure and rate of vehicle deceleration. The antilock system prevents lockup during high slip conditions by modulating fluid apply pressure to the brakes. The apply pressure is modulated according to wheel speed, degree of slip and rate of deceleration. A sensor at each wheel converts wheel speed into electrical signals.
The antilock brake system on the Rio is a 4-sensor, 4-channel system. In this configuration, the front wheels are controlled independently and rear wheels are controlled in tandem by a select low system (controlling hydraulic pressure on side on which slip is first occurred).