Anti-lock braking systems are designed to prevent locked-wheel skidding during hard braking or during braking on slippery surfaces. The front wheels of a vehicle cannot apply steering force if they are locked and sliding; the vehicle will continue in its previous direction of travel. The four wheel anti-lock brake systems found on Mazda vehicles holds the individual wheels just below the point of locking, which in turn allows some steering response and prevents the rear of the vehicle from sliding sideways.
Electrical signals are sent from the wheel speed sensors to the ABS control unit; when the system detects impending lock-up at any wheel, solenoid valves within the hydraulic unit cycle to control the line pressure as needed. The systems employ normal master cylinder and vacuum booster arrangements; no hydraulic accumulator is used, nor is any high pressure fluid stored within the system. The system employs a conventional master cylinder and vacuum booster arrangements; no hydraulic accumulator is used, nor is any high pressure fluid stored within the system.
The ABS system monitors and compares wheel speed based on the inputs from the wheel speed sensors. The brake pressure is controlled according to the impending lock-up computations of the ABS control unit.
If either front wheel approaches lock-up, the controller actuates the individual solenoid for that wheel, reducing pressure in the line. Impending lock-up at either rear wheel will engage the rear control solenoid; hydraulic pressure is reduced equally to both rear wheels, reducing the tendency of the rear to skid sideways under braking.