BRAKE CONTROL SYSTEM


  1. CONSTRUCTION


    1. The brake booster pump assembly consists of an accumulator and pump and pump motor.

    2. A plunger type pump is used. This pump is operated by the rotation of a camshaft driven by the pump motor, and supplies high-pressurized fluid to the accumulator.

    3. High-pressure nitrogen gas is charged and sealed in the accumulator. The accumulator has been made more compact by using a metallic bellows-formed tube.

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      *1 Pump Motor *2 Accumulator
      *3 Camshaft *4 Pump
      *5 High-pressure Nitrogen Gas *6 Bellows-formed Tube

  2. OPERATION


    1. The brake fluid that is discharged by the pump passes through the check valve and is stored in the accumulator. The hydraulic pressure that is stored in the accumulator is used for providing the hydraulic pressure that is needed for normal braking and for operating the brake control.

    2. The pump motor is activated upon receipt of signals from the skid control ECU to turn on the motor relays built into the skid control ECU.

    3. The accumulator pressure sensor constantly monitors the pressure in the accumulator and transmits it to the skid control ECU. If the accumulator pressure drops below the set pressure, the skid control ECU sends an activation signal to the motor relay in order to actuate the pump motor until the pressure in the accumulator reaches the set pressure.

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    4. If the pump and the pump motor continue to operate unintentionally, and the accumulator pressure sensor fails, a high pressure would be created in the accumulator. At this time, the relief valve will open and return the brake fluid to the brake master cylinder reservoir assembly, to reduce the accumulator pressure.

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    5. If the accumulator pressure drops abnormally to a level below the pressure set at the ECU, the skid control ECU illuminates the brake warning light / red (malfunction), the brake warning light / yellow (minor malfunction), ABS warning light, slip indicator light and the master warning light. Then, the multi buzzer in the combination meter assembly sounds to alert the driver of the abnormal hydraulic pressure.

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