Base Brakes (Friction Braking)

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The braking torque applied to the wheels in proportion to the driver's braking intent is achieved with a combination of regenerative braking from the powertrain and hydraulically applied friction braking controlled by the EHCU. The friction braking is achieved by the EHCU controlling a combination of valves in a way the allows accumulator pressure to be used to actuate the wheel brakes. The accumulator is maintained at pressure during normal operation by the pump and motor, independent of the brake being applied. The pressure built in the braking circuits by the EHCU by means of the boost valve is applied directly to the rear brakes. The front circuit pressure, however, are applied to the MC secondary pistons, and they in turn apply pressure to the front while brakes. The SCB system is designed and used with its EHCU and MC primary and secondary pistons configured as they are for fail-safe purposes.