GF32.32-P-0002RT Adaptive Damping System (ADS), Function

GF32.32-P-0002RT Adaptive damping system (ADS), function
- with CODE (489) Airmatic (air suspension with level adjustment and adaptive damping system ADS)
- up to model year 08


Overall ADS function
The "adaptive damping system" (ADS) adapts the damping forces to the road surface condition and driving style or driver's wishes. The signals from the left front body lateral acceleration sensor (B24/3), right front body lateral acceleration sensor (B24/4) and right rear body lateral acceleration sensor (B24/6) are used by the AIRmatic with ADS control unit (N51) t determine the vertical speed. The signals of the wheel speeds and steering angle sensor (N49) are used to calculate longitudinal and lateral acceleration. The left front axle damping valve unit (Y51), right front axle damping valve unit (Y52), left rear axle damping valve unit (Y53) and right rear axle damping valve unit (Y54) are used by the AIRmatic with ADS control unit to control the damping force on each wheel.

Each individual damping valve unit can thus be actuated using a different characteristic. The extremely short adjusting time (milliseconds) means that an optimum damping force setting is available almost immediately if sudden changes in the vehicle level are required.

Evaluation of the stop lamp switch signal enables brake applications to be quickly detected and any vehicle pitch motion to be reduced through suitable damper settings.

The driver can select between a comfort-oriented, automatic and a sporty map using the Comfort/Sport switch (ADS) (N72/1s31).

Skyhook algorithm (control algorithm)
A decisive criterion for determining suitable damper force stages (damper adjustment) for each respective driving situation is the direction of movement taken by the vehicle body. In the event of an upward movement the damper must provide a firm rebound stage and a soft compression stage.

If movement is downwards then a soft rebound stage and a firm compression stage are required. The skyhook algorithm operates according to this principle.

Component Identification:

The damping force setting is regulated in the damping valve units. Each wheel has one damping valve unit installed between the upper and lower chambers of the single-pipe gas-filled shock absorber.

Function exemplified on left front axle suspension strut
The damping force setting is regulated in the left front axle damping valve unit. The front axle damping valve unit on the left front wheel is located between the upper and lower chambers of the single-pipe gas-filled shock absorber. The damping valve unit contains the solenoid valve 1, left front and solenoid valve 2, front left, which depending on actuation via the AIRmatic control unit 4 enable different damper force ratings to be achieved.