GF42.45-P-3500D ASC Control Mode, Function

GF42.45-P-3500D ASC control mode, function





ASR control mode - build up pressure
The control procedure and value positions illustrated in the example refer to the RR brake.

If one of the drive wheels begins to spin when the vehicle is starting off or accelerating, the ESP control unit initiates the ASR pressure build-up control mode. At the start of the ASR control the rear axle switchover solenoid valve (y19) is switched into the "Lock position" (closed) and the high-pressure and return pump (m1) is actuated.

The rear axle inlet solenoid valve (y23) is only opened during the pressure buildup phases. In the process the rear axle pump (p2) draws brake fluid out of the reservoir (y23) via the rear axle inlet solenoid valve and via the master brake cylinder.

The pressure limiting valve integrated in the rear axle switchover solenoid valve (y19) serves high pressure limitation (min. 150 bar).





ASR control mode - hold pressure
The control procedure and value positions illustrated in the example refer to the RR brake.

The hold pressure ASR control mode begins when strong brake intervention is no longer required to prevent drive slip.

The rear axle inlet solenoid valve (y23) and right rear solenoid valve (pressure hold) (y12) are closed. As a result the pressure in the brake caliper cannot be increased via the rear axle pump (p2).





ASR control mode - reduce pressure
The control procedure and value positions illustrated in the example refer to the RR brake.

The pressure reduction ASR control mode begins if the braking pressure required to prevent drive slip is too high. The pressure reduction phase is introduced by opening the right rear solenoid valve (pressure release) (y13). The right rear solenoid valve (pressure hold) (y12) remains closed.

The brake fluid flowing back returns to the brake fluid reservoir via the rear axle pump (p2) through the pressure limiting valve integrated in the rear axle switchover solenoid valve (y19) via the master brake cylinder.

The rear axle pump (p2) is actuated pulsed during all control phases (depending on the requirement)..

Different damping components (12, 13, 14) are installed to further reduce noise levels.