P32.32-2213-79
Block diagram |
A1 | Instrument cluster | L6/2 | Right front axle rpm sensor | N72/1s23 | Vehicle dynamics button | ||
B22/7 | Left rear level sensor | L6/3 | Left rear axle rpm sensor | N73 | Electronic ignition switch control unit | ||
B22/8 | Left front level sensor | L6/4 | Right rear axle rpm sensor | N80 | Steering column module control unit | ||
B22/9 | Right front level sensor | N3/9 | CDI control unit (with diesel engine) | Y51 | Left front axle damping valve unit | ||
B22/10 | Right rear level sensor | N3/10 | ME-SFI [ME] control unit (with gasoline engine) | Y52 | Right front axle damping valve unit | ||
B24/3 | Left front body lateral acceleration sensor | N10/1 | Front SAM control unit with fuse and relay module | Y53 | Left rear axle damping valve unit | ||
B24/4 | Right front body lateral acceleration sensor | N30/4 | Electronic Stability Program control unit | Y54 | Right rear axle damping valve unit | ||
B24/6 | Right rear body lateral acceleration sensor | N49 | Steering wheel angle sensor | CAN E | Chassis CAN | ||
B24/15 | Turn rate, lateral acceleration and longitudinal acceleration sensor (with code 233 (DISTRONIC PLUS)) | N51/5 | Adaptive damping system control unit | CAN H | Vehicle dynamics CAN | ||
L6/1 | Left front axle rpm sensor | N72/1 | Upper control panel control unit | LIN 1 | Instrument panel LIN |
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 ADS is a combination of steel suspension with continuous damper adjustment.
The damping characteristic is adapted on a wheel specific basis to the road surface condition and the driving style to match the selected damping mode.
The damping mode can be selected by the driver at the press of a button, whereby the last selected setting is retained after a driving cycle.
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 the ME-SFI control unit (with gasoline engine) makes the "circuit 61 ON" status available on the chassis CAN.
With the ADAPTIVE BRAKE premium system, the data from the turn rate, lateral acceleration and longitudinal acceleration sensor (with code 233 (DISTRONIC PLUS)) is read in by the Electronic Stability Program control unit via the vehicle dynamics CAN.
With the ADAPTIVE BRAKE basic system (except code 233 (DISTRONIC PLUS)), the turn rate, lateral acceleration and longitudinal acceleration sensor is integrated in the Electronic Stability Program control unit, thereby making a CAN connection to an external turn rate, lateral acceleration and longitudinal acceleration sensor unnecessary. The data for turn rate, lateral acceleration and longitudinal acceleration is therefore collected and evaluated directly by the Electronic Stability Program control unit.
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
Right rear body lateral acceleration sensor
The adaptive damping system control unit reads in the signals of the listed components directly. The vehicle's longitudinal acceleration and lateral acceleration is detected by the turn rate, lateral acceleration and longitudinal acceleration sensor (with ADAPTIVE BRAKE premium system) via the vehicle dynamics CAN or directly by the Electronic Stability Program control unit (with the ABR basic system). The Electronic Stability Program control unit makes the data available to the adaptive damping system control unit on the chassis CAN. The Electronic Stability Program control unit also sends information on the wheel speeds, brake status and the braking torque over the chassis CAN to the adaptive damping system control unit. This information is used for computation of the vehicle speed and the probable chassis movement.
The adaptive damping system control unit also receives the following information via the chassis CAN, which is used for calculating the ideal damping stage or damping force at each of the dampers:
Steering wheel angle and steering wheel velocity, recorded by the steering wheel angle sensor, provided by the steering column tube module control unit
Kickdown request (with automatic transmission), from the CDI control unit (with diesel engine) or from the ME-SFI control unit (with gasoline engine)
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 front SAM control unit with fuse and relay module reads in the status of the vehicle dynamics button via the instrument panel LIN and sends it via the 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. If Sport mode is selected, the LED integrated in the vehicle dynamics button lights up. The adaptive damping system control unit sends the request for actuation of this LED via the chassis CAN to the front SAM control unit with fuse and relay module. The front SAM control unit with fuse and relay module actuates the LED in the vehicle dynamics button via the instrument panel LIN. If the "COMFORT" mode is selected by pressing the vehicle dynamics button again, the LED in the vehicle dynamics button goes out.
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 the ideal damping stage in each case 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 continuous damping adjustment is realized using twin-tube gas-filled 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
- gf3232p9997rd Overview of system components for adaptive damping system (ADS)
- gf3232p9997rda Overview of system components for adaptive damping system (ADS)