BRAKE CONTROL SYSTEM
5A–7
Pressure Reduction
Once the brake pressure is isolated, it must be reduced
to allow the wheels to unlock. This is accomplished by
dumping a portion of the brake fluid pressure into a low
pressure accumulator.
The microprocessor activates the normally closed dump
valve to open, allowing fluid from the wheels to be
dumped into the accumulator. This is done with very
short activation pulses opening and closing the dump
valve passageway. Brake pressure is reduced at the
wheel and allows the wheel to begin rotating again. The
fluid from the brake piston is stored in the accumulator
against spring pressure and a portion of this fluid also
primes the pump.
The dump valves are operated independently to control
the deceleration of the wheel. At this point, the brake
pedal is isolated from the base brake system, the
hydraulic control unit pumps are primed and the
attenuators are ready to pump fluid.
C05RW009
Legend
EndOFCallout
(1) Brake
(2) Master Cylinder
SECTION