ELECTRONICALLY CONTROLLED BRAKE SYSTEM SYSTEM DESCRIPTION


  1. FUNCTION DESCRIPTION


    1. Electronically Controlled Brake System


      1. Upon receiving signals from the skid control ECU, this system effects hydraulic pressure control at the 4 wheels.

    2. Regenerative Brake Cooperative Control


      1. Controls hydraulic braking in order to recover electrical energy by utilizing the regenerative braking of the hybrid system as much as possible.

    3. SPORT Mode


      1. SPORT mode performs integrated control of engine output, traction control and steering control to ensure vehicle running and cornering performance.

    4. VSC(+) (Cooperative Control with EPS)


      1. Effects cooperative control with the power steering ECU in order to provide steering assist in accordance with the operating conditions of the vehicle.

    5. Anti-lock Brake System (ABS)


      1. The ABS helps prevent the wheels from locking when the brakes are applied firmly or when braking on a slippery surface.

    6. Electronic Brake Force Distribution (EBD)


      1. The EBD control utilizes ABS, realizing proper brake force distribution between the front and rear wheels in accordance with the driving conditions. In addition, during braking while cornering, it also controls the brake forces of the right and left wheels, helping maintain vehicle behavior.

    7. Brake Assist (BA)


      1. The primary purpose of BA is to provide an auxiliary brake force to assist a driver who cannot generate a large brake force during emergency braking, thus helping draw the vehicle's braking performance.

    8. Traction Control (TRC)


      1. The TRC helps restrain the slippage of the drive wheels if the driver depresses the accelerator pedal excessively when starting off or accelerating on a slippery surface.

    9. Vehicle Stability Control (VSC)


      1. The VSC helps restrain sideways slippage of the vehicle during a strong front wheel skid or strong rear wheel skid, during cornering.

    10. Hill-start Assist Control


      1. When starting uphill, this control maintains the brake hydraulic pressure to the 4 wheels, in order to momentarily prevent the vehicle from descending backward.

    11. Emergency Brake Signal


      1. In the case of emergency braking, emergency stop light control flashes the stoplights to alert the drivers in following vehicles.

    12. Dynamic Radar Cruise Control (w/ Dynamic Radar Cruise Control System)


      1. When the driving support ECU determines that a large deceleration is required based on the distance to the preceding vehicle and the relative vehicle speed during the dynamic radar cruise control system operation, the skid control ECU operates the brake system according to the signal from the driving support ECU.

    13. Pre-collision Control (w/ Pre-collision System)


      1. When the driving support ECU determines a high possibility of collision, the skid control ECU activates the pre-collision brake assist or the pre-collision brake according to the signal from the driving support ECU.

  2. FUNCTION OF COMPONENTS

    Component Function
    Brake Booster with Master Cylinder Brake Actuator

    • Consists of 4 switching solenoid valves, 2 linear solenoid valves, 8 control solenoid valves.

    • Changes the brake fluid path based on the signals from the skid control ECU during the operations of the ABS with EBD, BA, TRC, VSC and hill-start assist control in order to control the fluid pressure that is applied to the wheel cylinders.
    Hydraulic Brake Booster

    • Generates hydraulic pressure in accordance with the amount of effort applied to the brake pedal by the driver.

    • When a malfunction occurs in the brake system, the hydraulic brake booster supplies the fluid pressure (which is generated by the brake pedal effort) directly to the wheel cylinders.
    Stroke Simulator Generates a pedal stroke during braking in accordance with the driver's pedal effort.
    Brake Actuator Skid Control ECU

    • Monitors the driving conditions of the vehicle in accordance with the signals received from the sensors and through cooperative control with the power management control ECU and power steering ECU calculates the required amount of braking force, and controls the brake actuator.

    • Judges the vehicle driving condition based on signals from each sensor, and controls ABS with EBD, BA, TRC, VSC and hill-start assist control.

    • Operates the brake booster pump to control accumulator pressure based on accumulator pressure sensor signal.
    Skid Control ECU Solenoid Relay Supply or cut off power to solenoid valves in the brake actuator.
    Motor Relay Normally supplies power to the pump motor using 2 out of 3 relays. Ensures power to the pump motor by using the other relay if the skid control ECU detects a malfunction.
    Relief Valve Returns the brake fluid to the reservoir tank to prevent excessive pressure if the pump operates continuously due to a malfunction of the accumulator pressure sensor.
    Linear Solenoid Valve Controls the wheel cylinder pressure to generate a braking force responsive to the braking force requirement when the brake pedal is depressed normally.
    Switching Solenoid Valve Switches the brake hydraulic path when the brake control system is activated.
    Control Solenoid Valve Controls the wheel cylinder pressure when the ABS with EBD, BA, TRC, VSC and hill-start assist control are activated.
    Regulator Pressure Sensor The regulator pressure sensor converts the fluid pressure generated by the hydraulic brake booster into electrical signals and transmits them to the skid control ECU. Accordingly, the skid control ECU determines the braking force required by the driver.
    Wheel Cylinder Pressure Sensor This sensor detects the fluid pressure that acts on the respective wheel cylinders and transmits them to the skid control ECU in the form of feedback. Accordingly, the skid control ECU monitors the fluid pressure of the wheel cylinders and controls the control solenoid valve, in order to achieve the optimal wheel cylinder pressures.
    Accumulator Pressure Sensor The accumulator pressure sensor constantly detects the brake fluid pressure in the accumulator and transmits the signals to the skid control ECU. Accordingly, the skid control ECU controls the pump motor.
    Brake Booster Pump Consisting of a pump, pump motor and accumulator, the hydraulic power source portion generates and stores the hydraulic pressure, which the skid control ECU uses for controlling braking.
    Speed Sensor Detects the wheel speed of each of 4 wheels.
    Brake Pedal Stroke Sensor Directly detects the extent of the brake pedal stroke operated by the driver.
    Steering Angle Sensor Detects the steering direction and angle of the steering wheel.
    Yaw Rate and Acceleration Sensor

    • Detects the vehicle's yaw rate.

    • Detects the vehicle's acceleration in the forward, rearward, and lateral.
    Brake Master Cylinder Reservoir Stores brake fluid.
    Brake Master Cylinder Reservoir Brake Fluid Level Warning Switch Detects the low brake fluid level.
    Parking Brake Switch Detects the parking brake pedal status.
    Stop Light Switch Detects the brake pedal operation.
    Combination Switch Traction Control Switch Enables the driver to select Normal mode, or TRC off mode.
    Stop Light Control Relay

    • Illuminates the stop lights while dynamic radar cruise or pre-collision control is operating.

    • Blinks the stop lights while emergency stop light control is operating.
    Power Steering ECU Operates cooperatively with the skid control ECU to control the steering assist torque.
    Main Body ECU (Instrument Panel Junction Block)

    • Detects the parking brake signal and outputs it to the skid control ECU via CAN communication.

    • Detects the hazard switch on/off signal and outputs it to the skid control ECU via CAN communication.
    Power Management Control ECU

    • Actuates the regenerative braking on receiving signal from the skid control ECU.

    • Sends the actual regenerative brake control value to the skid control ECU.

    • Controls the motive force based on an output control request signal received from the skid control ECU while the VSC, TRC or the dynamic radar cruise control system is operating.
    Combination Meter ABS Warning Light Lights up to alert the driver when the skid control ECU detects the malfunction in the ABS, EBD or BA.
    Brake Warning Light / Red (Malfunction)

    • Lights up to alert the driver when the skid control ECU detects the malfunction in the apportioning of the brake.

    • Lights up to inform the driver when the parking brake is on or the brake fluid level is low.
    Brake Warning Light / Yellow (Minor Malfunction) Lights up to alert the driver when a minor malfunction occurs in the brake system, which does not affect the braking force (such as a malfunction in the regenerative braking).
    Slip Indicator Light

    • Blinks to inform the driver when the ABS, the TRC or the VSC is operated.

    • Lights up to alert the driver in the event of malfunction of the TRC, VSC or hill-start assist control.
    TRC OFF Indicator Light Illuminates to inform the driver when TRC off mode is selected.
    Meter Buzzer This buzzer sounds continuously to inform the driver when there is a malfunction in the hydraulic pressure or a failure in the power supply.