System Outline

(ABS)
ABS is a brake system designed for the purpose to improve the operating ability securing the stability of the vehicle by preventing the looking-up of the vehicle controlling the wheel cylinder pressure of all the four wheels at the time of sudden braking.

1. INPUT SIGNALS
1. Speed Sensor Signal
The speed of the wheels is detected and input to TERMINALS FL+, FR+, RL+ and RR+ of the ABS and traction ECU.
2. Stop Light SW Signal
A signal is input to TERMINAL STP of the ABS and traction ECU when brake pedal is depressed.

2. SYSTEM OPERATION
When the wheels are to be locked-up, the solenoid inside the actuator will be controlled by the signal from the ABS actuator and ECU and the brake fluid in the wheel cylinder will flow through the reservoir and reduce the hydraulic pressure.

While the ABS is in operation, as the ABS actuator and ECU is always outputting the operation signal to the pump inside the actuator, brake fluids stored inside the reservoir will be suctioned up by the pump inside the actuator and returned to the master cylinder.

When the hydraulic pressure of the wheel cylinder is decompressed or increased until the necessary hydraulic pressure, the solenoid inside the actuator is controlled by the control signal from the ABS actuator and ECU and as a result. hydraulic pressure of the wheel cylinder will be closed at both routes of the master cylinder and reservoir sides and the hydraulic pressure of the wheel cylinder will become to be in the holding condition.

If the increase of hydraulic pressure volume of the wheel cylinder becomes necessary, with the control signal from the ABS actuator and ECU. The solenoid inside the actuator will be controlled and become the same condition as usual and the brake fluid of the master cylinder will be sent to the wheel cylinder and will increase the hydraulic pressure of the wheel cylinder. At this time, in the case that the brake fluid stays left in the reservoir, it will be suctioned up by the pump inside the actuator and will be sent to the wheel cylinder.

Also, increasing speed of the hydraulic pressure is controlled by outputting the increasing and the said holding one after another.