ASR Systems Hydraulic Unit, Function
The ABS, ASR and ESP switching components are combined in the traction systems hydraulic unit.
During ASR function, switchover solenoid valve (y5) locks the rear axle circuit to the brake master cylinder. Solenoid valve (y5) also functions as a pressure relief valve and opens at approximately 160 bar. Pulsating brake fluid noise is reduced by a diaphragm discharge damper (12) and returned to the brake master cylinder. A muffler (10) is in place for each brake circuit to reduce delivery noise. During ABS, ETS or ASR pressure reduction operation, the brake fluid flows back to the high pressure and return pump via the accumulator.