ADAPTIVE VARIABLE SUSPENSION SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Shock Absorber Assembly Absorber Control Actuator Changes the damping force of the shock absorber assembly.
    Acceleration Sensor Detects the vertical acceleration rate of the body.
    Steering Sensor Detects the steering direction and the angle of the steering wheel.
    Airbag ECU Assembly Deceleration Sensor Detects the vehicle's longitudinal and lateral deceleration.
    Speed Sensor Detects the vehicle speed.
    Stop Light Switch Assembly Detects the brake pedal depression signal.
    Integration Control and Panel Assembly Drive Mode Select Switches the driving mode (NORMAL mode, ECO mode, SPORT S mode or SPORT S+ mode).
    Combination Meter Assembly Multi-information Display Displays the selection condition of the drive mode select.
    Absorber Control ECU (with Built-in Rear Acceleration Sensor)

    • Estimates the condition of the vehicle in accordance with the signals provided by the sensors and switches, and outputs control signals to the absorber control actuator.

    • Detects the vertical acceleration rate of the body.
    Driving Support ECU Assembly* Makes a request for damping force control to the absorber control ECU.
    Skid Control ECU

    • Sends the vehicle speed signal to the absorber control ECU.

    • Sends the wheel cylinder pressure signal to the absorber control ECU.

    • Makes a request for damping force control to the absorber control ECU.
    ECM Sends information of the drive mode selected through a drive mode select operation to the absorber control ECU.
    Hybrid Vehicle Control ECU Sends the motive force signal to the absorber control ECU.

    *: Models with pre-collision system

  2. SYSTEM CONTROL


    1. The absorber control ECU receives signals from the sensors and switches to control the absorber control actuators. The ECU uses these signals to optimally control the damping force in accordance with the driving conditions and road conditions.

    2. The AVS effects the following controls:

      Control Outline
      Vehicle Speed Sensing Control The system controls damping force in accordance with vehicle speed, aiming for both ride comfort at low speed and stability (a flat and stable drive) at high speed.
      Anti-dive Control Makes the damping force firmer to restrain the body dive during braking, thus ensuring excellent stability and controllability.
      Anti-squat Control Makes the damping force firmer during acceleration to minimize the changes in the vehicle body posture.
      Roll Posture Control The system controls the damping force to optimize the vehicle posture during turning to achieve both a vehicle posture that appeals to people's sensibilities and pleasant handling.
      Repercussion Control (Sprung Speed Proportional Control) Based on acceleration sensor signals, the system detects the effects of input from the road surface (vibrations in the heave, roll and pitch directions and shock absorber expansion and contraction) and performs fine-grained control of the damping forces of the 4 wheels. The highly responsive actuator greatly contributes to the fine-grained control, naturally dampening large vehicle movements to achieve pleasant riding comfort and a superior flat feeling.
      Roughness Sensing Control The system detects the unpleasant vibrations that occur when driving on rough roads based on acceleration sensor signals, and performs control to decrease the damping force. As a result, the rough feeling is eased to ensure riding comfort.
      Unsprung Damping Control The system detects unsprung resonance based on speed sensor signals and performs control to increase the damping force. As a result, unsprung resonance (clattering) is suppressed to ensure the road contact performance of the tires.
      VSC Operation Control The system appropriately controls the damping force according to whether the vehicle is sliding laterally and changes in the slipperiness of the road surface based on damping force cooperative control signals from the skid control ECU, improving VSC effectiveness.
      Pre-collision System Operation Control* When the driving support ECU assembly determines that a collision may occur, the system appropriately controls the damping force of the shock absorber based on damping force cooperative control signals. For details, see the Pre-collision System section.
      Damping Mode Selection The drive mode select enables the driver to select a desired damping force from the 2 modes.

      *: Models with pre-collision system

    3. Roll Posture Control


      1. In accordance with the steering sensor signal and deceleration sensor signal, the damping force of each wheel is controlled to optimize the vehicle posture condition while turning.

      2. Damping force is controlled to reduce the phase difference between the roll angle and pitch angle, thus achieving a vehicle posture compatible to the sensitivity of a human as well as comfortable steering.

        B002GCME03
        *1 Pitch Angle
        *2 With Control
        *3 Without Control
        *4 Roll Angle

    4. Repercussion Control (Sprung Speed Proportional Control)


      1. According to the vehicle speed in the heave, roll and pitch directions, the solenoid current (damping force) is precisely controlled in a continuous manner as shown below to naturally and steplessly suppress vehicle vibrations. Also, quick damping force switching response and an interval switching characteristic allow the vehicle to maintain a flat posture and cut off shocks even from road surfaces with large unevenness together with minute vibrations.


        • Based on the amount of vehicle movement and shock absorber expansion and contraction, if the shock absorber damping force is extending vehicle movement, the solenoid current (damping force) is reduced, but if the force is suppressing vehicle movement, the solenoid current (damping force) is increased.

        • The solenoid current (damping force) is increased when the vehicle moves quickly. On the other hand, the solenoid current (damping force) is increased and decreased in small amounts when the vehicle moves slowly.

    5. Damping Mode Selection


      1. Drive modes (NORMAL, ECO, SPORT S and SPORT S+) can be selected by a driving mode select operation.

      2. In NORMAL, ECO or SPORT S mode, achieves a good balance of high-level steering response, flat feeling, sense of stability and riding comfort.

      3. SPORT S+ mode mainly uses the hard damping force range to further emphasize steering response, flat feeling and stability, achieving sporty driving.

        B002GUWC02
        *1 Drive Mode Select *2 Integration Control and Panel Assembly
        B002GC6E01

  3. FAIL-SAFE


    1. If a malfunction occurs in the AVS, the absorber control ECU prohibits the damping force control.

  4. DIAGNOSIS


    1. The absorber control ECU will also store a Diagnostic Trouble Code (DTC). The DTC can be accessed through the use of a Global TechStream (GTS). For details, refer to the Repair Manual.