10-10
▶Pressure Decreases in the Circuit when ABS is Operating
Even when the hydraulic pressure on each circuit is stable, the wheel can be locked as the wheel speed
decreases. This is when the ABS ECU detects the wheel speed and the vehicle speed and gives the
optimized braking without locking the wheels. In order to prevent from hydraulic pressure increases, the
inlet valve is closed and the outlet valve is opened. Also, the oil is sent to the low pressure changer and
the wheel speed increases again. The ABS ECU operates the pump to circulate the oil in the low
pressure chamber to the master cylinder. This may make the driver to feel the brake pedal vibration and
some noises.
▶Pressure Increases in the Circuit when ABS is Operating
<0068009a0047009b008f008c0047009e008f008c008c00930047009a0097008c008c008b004700900095008a0099008c0088009a008c009a00530047009b008f008c0047009000950093008c009b0047009d00880093009d008c004700960097008c009500
9a004700880095008b0047009b008f008c0047009e008f008c>el’s pressure increases due to
the master cylinder pressure. The oil in the low pressure chamber circulates to the wheel by the pump
and the wheel speed decreases as the hydraulic pressure at wheel increases. This operation continues
repetitively until there are no signs that the ECU is locking the wheels. When the ABS hydraulic pressure
control takes place, there may be some vibration and noises at the brake pedal.
