DYNAMIC TORQUE CONTROL 4WD/AWD SYSTEM SYSTEM DESCRIPTION

  1. GENERAL DESCRIPTION

    The dynamic torque control 4WD/AWD system detects the driving conditions based on signals from each ECU, each switch, the steering angle sensor, the wheel speed sensor, and the acceleration sensor. The system controls the electronic current passing through the linear solenoid of the electromagnetic coupling, and performs electronic control to distribute the optimum torque to the rear wheels.

  2. FUNCTION OF MAIN COMPONENTS

    Component

    Function

    Combination Meter Assembly

    4WD/AWD Warning Light*1

    • Illuminates to warn the driver of a malfunction in the dynamic torque control 4WD/AWD system.

    • Blinks to inform the driver of the DTCs in diagnostic mode.

    Multi-information display (4WD/AWD Warning)*2

    Displays a warning to the driver when the system malfunctions.

    4WD/AWD Lock Mode Indicator Light

    • Illuminates to inform the driver of the lock mode control status.

    • When lock mode is turned ON, the indicator light blinks twice and then remains illuminated.

    • When lock mode is turned OFF, the indicator light turns off.

    Sport Mode Indicator Light*3

    Illuminates to inform the driver of the sport mode control status.

    Speed Sensors (4)

    Detect the wheel speed of each wheel.

    Crankshaft Position Sensor

    Detects the engine speed and outputs it to the ECM.

    Throttle Position Sensor

    Detects the throttle valve position and outputs it to the ECM.

    Park/Neutral Position Switch Assembly*4

    Detects the shift position of the transaxle and outputs it to the ECM.

    Stop Light Switch Assembly

    Detects when the brake pedal is depressed.

    Parking Brake Switch Assembly

    Detects when the parking brake is applied.

    Steering Angle Sensor (Spiral with Sensor Cable Sub-assembly)

    Detects the turning of the steering wheel.

    Acceleration Sensor (Airbag Sensor Assembly)

    Detects the vehicle's longitudinal acceleration and deceleration.

    Transfer

    Drive force input into the differential is redirected 90 degrees and output to the propeller shaft by the transfer.

    Rear Differential

    Transmission Coupling Assembly

    • 4WD Linear Solenoid

    Distributes drive torque in accordance with the amperage applied by the 4WD ECU assembly.

    4WD ECU Assembly

    Controls the amperage applied to the 4WD linear solenoid based on signals provided by the sensors in order to optimally distribute drive torque in accordance with driving conditions.

    ECM

    Outputs signals such as the shift position signal, throttle position signal, and crankshaft position signal to the 4WD ECU assembly.

    Skid Control ECU (Brake Actuator Assembly)

    Outputs signals such as the vehicle speed signal and deceleration signal to the 4WD ECU assembly.

    Main Body ECU (Multiplex Network Body ECU)

    Outputs signals such as the parking brake switch signal and ambient temperature signal to the 4WD ECU assembly via CAN communication.

    Transmission Coupling Assembly

    Distributes torque to the rear wheels based on the amount of current sent from the 4WD ECU assembly.

    4WD/AWD Lock Switch (Differential Lock Switch)

    Switches between auto mode and lock mode.

    Sport Mode Switch (Combination Switch Assembly)*3

    Switches between normal mode and sport mode.

    • *1: for Segment Display Type

    • *2: for TFT Display Type

    • *3: for Manual Transaxle

    • *4: for Automatic Transaxle or CVT

  3. DRIVING FUNCTION

    Control

    Function

    Starting Control

    Controls torque distribution to the rear wheels to ensure traction performance when starting off and to avoid the occurrence of tight corner braking phenomenon* when turning.

    Normal Control

    Controls torque distribution to maintain stability while cornering and acceleration performance when accelerating straight ahead.

    Reduces torque distribution to the rear wheels when driving is judged to be stable to improve fuel consumption.

    Control when Locked

    Controls torque distribution to the rear wheels to allow maximum traction performance.

    Cornering Control

    Uses pre-torque control, which is based on driver operation input, and yawrate feedback control, which is based on the vehicle status, to achieve the tracing performance desired by the driver.

    Braking Control

    When braking, cancels 4WD/AWD to improve braking effectiveness.

    VSC Cooperative Control

    When suddenly accelerating during cornering on slippery surfaces, etc., the dynamic torque control 4WD/AWD system and VSC function cooperate to perform control which achieves smoother acceleration and higher stability compared to previous TRC and VSC functions.

    Safety Control

    May stop 4WD/AWD control and set the front wheels as the drive wheels if a malfunction is detected in the dynamic torque control 4WD/AWD system or other related systems, and warns the driver.

    Stops 4WD/AWD control, sets the front wheels as the drive wheels and warns the driver if there is a possibility that the drivetrain could be damaged.

    • *: Tight corner braking phenomenon: a phenomenon in which a 4WD/AWD vehicle may lurch and decelerate due to a rotational speed difference between the front and rear wheels, such as during low-speed cornering in 4WD/AWD mode.