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

Model 213 

up to model year 2021 

with code 459 (Steel suspension with adjustable damping) 

G13771773Courtesy of MERCEDES-BENZ USA

Block diagram 

Function requirements, general 

IMPORTANT The electronic ignition lock control unit sends the status of circuit 15 to the adaptive damping system control unit via suspension FlexRay.

Adaptive damping system (ADS), general 

ADS is a continuous damping adjustment system where damping is adapted at each individual wheel. This improves driving safety and driving comfort.

Adjustment of the damping depends on the following factors:

The damping is adjusted harder or softer depending on the driving situation. If the sensor system records a sporty driving style for example, the comfortable basic damping becomes harder automatically. The electronics works continuously within a broadly spread damping performance map. The damping force is adapted to each wheel individually. As a result, the vehicle rolls smoothly even on poor road surfaces, without impairing driving stability. The previously set damping stage is active when the ignition is switched on.

The ADS function comprises the following subfunctions:

Selection of transmission mode 

Depending in the selected transmission mode, the damping is set correspondingly harder or softer.

By operating the DYNAMIC SELECT switch in the left lower control panel (in automatic transmissions) or in the right lower control panel (in manual transmissions), the driver can choose between preconfigured drive programs or an individual drive program.

Depending on the selected transmission program, one of the following settings is activated for the suspension:

The left lower control panel (in automatic transmissions) or the right lower control panel (in manual transmissions) sends the status of the DYNAMIC SELECT switch to the Electronic Stability Program control unit via LCP-LIN, Audio/COMAND control panel or touchpad, telematics CAN, head unit, user interface CAN, electronic ignition lock control unit and suspension FlexRay. The Electronic Stability Program control unit then sends the request for the selected transmission mode via the chassis FlexRay to the adaptive damping system control unit.

The adaptive damping system control unit receives the corresponding request and generates the required actuation signals for the actuators. The selected transmission mode is displayed in the instrument cluster. The current transmission mode settings are also briefly shown in the Audio/COMAND display.

The adaptive damping system control unit sends information about the selected transmission mode via the chassis FlexRay, electronic ignition lock control unit and user interface CAN to the head unit and to the instrument cluster. The head unit generates the corresponding image data and sends a switch-on request to the Audio/COMAND display via telematics CAN. The image data is transmitted via the highspeed video link to the Audio/COMAND display.

Recording of driving condition 

The driving condition is defined by the following variables:

The vehicle body acceleration is recorded by the following sensors:

The adaptive damping system control unit reads in the signals from the level sensors directly.

The Electronic Stability Program control unit also transmits information about the wheel speeds, the brake status and the braking torque via chassis FlexRay to the adaptive damping system control unit. This information is used for computation of the vehicle speed and the vehicle body acceleration.

The supplemental restraint system control unit sends information about the turn rate, the lateral acceleration and the longitudinal acceleration via the vehicle dynamics CAN, the Electronic Stability Program control unit and the chassis FlexRay to the adaptive damping system control unit.

The adaptive damping system control unit also receives the following information via chassis FlexRay, which is used to calculate the ideal damping stage or damping force at each shock absorber:

Damping adjustment 

The adaptive damping system control unit uses the input signals (driving condition) to determine the ideal damping stage in each case and then actuates the following components directly:

The continuous damping adjustment is implemented using single-tube gas-filled shock absorbers. The damping valve units are located at the bottom side on the single-tube gas-filled shock absorbers.

A check valve is integrated into each of the main pistons and bottom valve of the single-hose gas-filled strut. These check valves ensure that an identical flow direction is given through the damping valve unit, both in the rebound and the compression stages. This design enables the damping valve unit of a shock absorber to consist of a single regulated proportional valve only.

The flow area in the damping valve unit can be continuously adjusted through actuation of this proportional valve. More or less oil can flow through the damping valve unit to match the set cross section. The damping behavior then becomes correspondingly softer or harder.

With activated ESP®, the damping is automatically switched over to the hard damping stage (Sport) in critical driving situations irrespective of the driver's request in order to achieve a more stable driving condition. The hard damping stage remains active for as long as the driving situation requires this.

  Electrical function schematic for adaptive damping system (ADS)   PE32.32-P-2051-97DBA
  Overview of system components for adaptive damping system (ADS)   GF32.32-P-9997FG