SAFARI

ABS

ANTI-LOCK BRAKES

B. Pressure Reduction Phase

Even after the pressure hold phase, if already the

existing pressure in the wheel cylinder is too much,

by which the wheel is further tending to lock, then

the ECU activates outlet solenoid valve and lets

some amount of brake fluid to reach the accumulator,

which serves the purpose of temporary storage.

ECU activates both Inlet & Outlet solenoid valves.

The closed Inlet solenoid valve shuts the liquid

channel from master cylinder. The outlet valve opens

and connects the wheel circuit to the reservoir. Refer

Fig. 7. Brake fluid gets discharged into the

accumulator. The recirculation pump (which is driven

by a motor which is not shown in the figure) pumps

the brake fluid back to the master cylinder through

the damping chamber. The damping chamber avoids

the pulsations of the returning brake fluid from

getting transferred to the driver’s foot. The pressure

reduction is continued till the wheel speed recovers

to the vehicle reference speed.

Solenoid valve

Electricity status

Valve open-close

Open-close channel

INLET

Master cylinder-Wheel cylinder

OUTLET

OPEN

Wheel cylinder-reservoir

Fig. 7

(Open)