P32.32-2241-79
Block diagram |
A1 | Instrument cluster | L6/3 | Left rear axle rpm sensor | N73 | Electronic ignition switch control unit | ||
B22/7 | Left rear level sensor | L6/4 | Right rear axle rpm sensor | N80 | Steering column module control unit | ||
B22/8 | Left front level sensor | N3/9 | CDI control unit (with diesel engine) | Y51 | Left front axle damping valve unit | ||
B22/9 | Right front level sensor | N3/10 | ME-SFI [ME] control unit (with gasoline engine) | Y52 | Right front axle damping valve unit | ||
B22/10 | Right rear level sensor | N10/1 | Front SAM control unit with fuse and relay module | Y53 | Left rear axle damping valve unit | ||
B24/3 | Left front body lateral acceleration sensor | N30/4 | Electronic Stability Program control unit (except CODE 233 (DISTRONIC PLUS)) | Y54 | Right rear axle damping valve unit | ||
B24/4 | Right front body lateral acceleration sensor | N30/7 | Premium Electronic Stability Program control unit (with CODE 233 (DISTRONIC PLUS)) | CAN E | Chassis CAN | ||
B24/5 | Left rear body lateral acceleration sensor | N49 | Steering angle sensor | CAN H | Vehicle dynamics CAN | ||
B24/15 | Yaw rate sensor for lateral and longitudinal acceleration | N51/5 | Adaptive damping system control unit | LIN 1 | Instrument panel LIN | ||
L6/1 | Left front axle rpm sensor | N72/1 | Upper control panel control unit | ||||
L6/2 | Right front axle rpm sensor | N72/1s23 | Vehicle dynamics button |
Function requirements, general
Circuit 15 ON
The circuit status is placed on the chassis CAN by the electronic ignition lock control unit.
Adaptive damping system (ADS), general
The adaptive damping system alters the damping characteristics of the dampers to match the selected driving style damping mode and the road surface condition. In doing so a choice can be made between a sporty or a comfortable suspension tuning.
The ADS consists of the following component functions:
Record function sequence for driving condition
Select function sequence for damping mode
Function sequence, shock absorber adjustment
Record additional function requirements for driving condition
Circuit 61 ON
The CDI control unit (with diesel engine) or ME-SFI control unit (with gasoline engine) makes the circuit status available on the chassis CAN.
Record function sequence for driving condition
The driving condition is defined through the following variables:
Vehicle level and damping speed
Vehicle body acceleration (chassis movement)
Vehicle longitudinal and lateral acceleration
The vehicle level and damping speed are recorded by the following components:
Left front level sensor
Right front level sensor
Left rear level sensor
Right rear level sensor
The vehicle body acceleration is recorded by the following components:
Left front body lateral acceleration sensor
Right front body lateral acceleration sensor
Left rear body lateral acceleration sensor
The adaptive damping system control unit reads in the signals of the listed components directly. The longitudinal and lateral acceleration of the vehicle is detected by the turn rate, lateral acceleration and longitudinal acceleration sensor. The data from the turn rate, lateral acceleration and longitudinal acceleration sensor is read in by the Electronic Stability Program control unit (except code 233 (DISTRONIC PLUS)) or by the Premium Electronic Stability Program control unit (with code 233 (DISTRONIC PLUS)) via the vehicle dynamics CAN and made available to the adaptive damping system control unit on the chassis CAN. The Electronic Stability Program control unit (except CODE 233 (DISTRONIC PLUS)) or the Premium Electronic Stability Program control unit (with CODE 233 (DISTRONIC PLUS)) sends information on the wheel speeds, brake status and braking torque to the adaptive damping system control unit via chassis CAN. This information is used for computation of the vehicle speed and the probable chassis movement.
The Electronic Stability Program control unit (except code 233 (DISTRONIC PLUS)) or the Premium Electronic Stability Program control unit (with code 233 (DISTRONIC PLUS)) receives the wheel speeds from the left front axle rpm sensor, right front axle rpm sensor, left rear axle rpm sensor and right rear axle rpm sensor.
The adaptive damping system control unit also receives the following information over the chassis CAN, which is used for calculating the ideal damping stage or damping force at each of the dampers:
Body variant, from the front SAM control unit with fuse and relay module
Steering angle and steering angle rate of change detected by the steering angle sensor and provided by the steering column tube module control unit
Drive type and kickdown request (with automatic transmission), from the CDI control unit or from the ME-SFI control unit
Vehicle speed as substitute value from instrument cluster
Select function sequence for damping mode
Pressing the vehicle dynamics button on the upper control panel control unit enables a choice to be made between a sporty or a comfortable suspension tuning.
The upper control panel control unit reads in the status of the vehicle dynamics button directly and sends it via the instrument panel LIN, front SAM control unit and chassis CAN 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. When the "SPORT" mode is selected, the light-emitting diode (LED) integrated in the vehicle dynamics button lights up. The adaptive damping system control unit sends the request for actuation of this LED over the chassis CAN to the front SAM control unit. The front SAM control unit actuates the LED in the vehicle dynamics button over the instrument panel LIN. If the vehicle dynamics button is pressed again for the "COMFORT" mode, the LED in the vehicle dynamics button goes off.
Additional function requirements for shock absorber adjustment
Circuit 61 ON
Function sequence, shock absorber adjustment
The input signals are used by the adaptive damping system control unit to determine each ideal damping stage and directly actuates the following components accordingly:
Left front axle damping valve unit
Right front axle damping valve unit
Left rear axle damping valve unit
Right rear axle damping valve unit
Implementation of the continuous damping adjustment is realized using twin-tube gas-operated shock absorbers. The damping valve units are located at the bottom side on the twin-tube gas-operated shock absorbers.
A check valve is integrated into the main pistons and the bottom valve of the twin-tube gas-filled shock absorber. 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.
Referenced documents
- gf3232p9997ca Overview of system components for adaptive damping system (ADS)