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Distance Control Detailed Information - GF30.30-S-1101B

Model 447 

With Code ET4 (Active Distance Assist DISTRONIC) 

With Code XM7 (MOPF II) 

G16501023Courtesy of MERCEDES-BENZ USA

Overview of distance control, Shown On Model 447.8 with engine OM654 

G16501024Courtesy of MERCEDES-BENZ USA

Overview of distance control, Shown On Model 447.6/7 with engine OM654 

Topology of distance control, Shown On Model 447.8 with engine OM654 

G16501025Courtesy of MERCEDES-BENZ USA

Topology of distance control, Shown On Model 447.6/7 with engine OM654 

G16501026Courtesy of MERCEDES-BENZ USA

Overview 

This document contains information on:

General 

The electric controller unit for Active Distance Assist DISTRONIC (B92/1) is located centrally behind the bumper.

Function requirements 

Function 

DISTRONIC in general 

IMPORTANT The following specified speed units and values should be assigned to the possible national versions. The details in mph ("miles per hour") refer to vehicles with a miles indicator.

DISTRONIC (code ET4 (Active Distance Assist DISTRONIC)) automatically regulates the speed and the distance to the vehicle in front according to the specification of the driver in a vehicle speed range from v = 0 to 200 km/h and from v = 200 to 0 km/h (v = 0 to 120 mph and from v = 120 to 0 mph).

The control is realized by the Active Distance Assist DISTRONIC electric controller unit (B92/1). The electric controller unit for Active Distance Assist DISTRONIC (B92/1) intervenes in the engine management and braking system to implement DISTRONIC active.

There is a distance warning function in DISTRONIC that warns the driver, visually and acoustically, when the distance to the vehicle in front is too low as well as of possible collisions with vehicles or stationary obstacles in its lane. If the driver reacts to the warning tone and brakes, they will be supported in this by Active Brake Assist (with code BA3 (Active Brake Assist)).

This calculates the required brake force amplification according to the situation. A possible collision can be prevented or at least its consequences can be mitigated.

The visual warnings and warning tones are output via the instrument cluster (A1) (model 447.6/7)/instrument cluster control unit (N133/1) (model 447.8):

The distance display can be switched on/off using the menu settings in the instrument cluster (A1) (model 447.6/7)/instrument cluster control unit (N133/1) (model 447.8).

The electric controller unit for Active Distance Assist DISTRONIC (B92/1) is connected to the on-board electronics via suspension FlexRay (Flex E).

DISTRONIC requires the following input parameters to implement the distance control and distance warning functions:

The integral radar sensor performs a soiling and function test to secure its perfect function after every engine start. The function test requires an object to be located in the detection area the radar sensor, that is used as a reference value for the function test.

If a malfunction is detected or no objects (for the function test) are present in the detection range, the DISTRONIC cannot be activated.

Operation 

DISTRONIC is operated via the left multifunction steering wheel button group (S110). The operation signals from the left multifunction steering wheel button group (S110) are read in by the steering wheel electronics (N135) via the steering wheel CAN (CAN LR) and then forwarded via the steering wheel CAN (CAN LR) to the steering column tube module (MRM) control unit (N80). The steering column tube module (MRM) control unit (N80) transmits this via suspension FlexRay (Flex E) to the electric controller unit for Active Distance Assist DISTRONIC (B92/1).

Layout of the left multifunction steering wheel button group 

G16501027Courtesy of MERCEDES-BENZ USA

Control elements on the instrument cluster multifunction steering wheel button group 

G16501028Courtesy of MERCEDES-BENZ USA
Item Designation Function
1.1 "Back" button Pressing on this button returns to the last display and exits the current menu.
1.2 Instrument cluster finger navigation pad You can navigate in the menu using one-finger swipes. Pressing the button confirms the current selection. The sensitivity for touch control can be set in the menu settings of the multimedia system.
1.3 Main menu button Pressing the button opens the main menu.
1.4 Cruise control button Cruise control is selected using this button.
1.5 Resume cruise control button A stored speed or a detected speed in vehicles with automatic speed control is adopted using this button.
1.6 Cruise control and limiter button This button activates cruise control or the variable limiter. The speed is increased by 1 km/h with a swipe. Pressing the button increases speed by 10 km/h.
1.7 Distance Assist button This button sets the specified distance to the vehicle in front.
1.8 Limiter button This button activates the variable limiter.
1.9 Switch off cruise control and limiter button. This button deactivates the Active Distance Assist DISTRONIC or the variable limiter.
1.10 Cruise control and limiter button This button activates cruise control or the variable limiter. The speed is reduced by 1 km/h with a swipe. Pressing the button reduces speed by 10 km/h.
1.11 Variable speed limiter and Proximity Control Assist button You can swap between the limiter and Distance Assist using this button.

Input parameters 

The electric controller unit for Active Distance Assist DISTRONIC (B92/1) evaluates the following input parameters:

IMPORTANT The electric controller unit for Active Distance Assist DISTRONIC (B92/1) compares the actual acceleration with the requested acceleration. If the actual acceleration is not sufficient, then a higher torque is requested (e.g. situation on hill).

IMPORTANT For reasons of safety and comfort, the maximum (positive) acceleration of the automatic distance control is limited to approx. a = 3.5 m/s2 . It is dependent on the selected transmission mode and it responds anti-proportional to the vehicle speed. With increasing vehicle speed smaller accelerations are permitted.

Output parameters 

The electric controller unit for Active Distance Assist DISTRONIC (B92/1) outputs the following output parameters (requests):

DISTRONIC function sequence 

The description of the DISTRONIC function takes place, as an example, in the following chronological sequence:

The sequence can vary depending on the driver requests and the current traffic situation.

Automatic distance control

Automatic distance control can be activated while driving (v < 30 km/h (20 mph)) only if a vehicle in front has been detected. If the vehicle traveling in front brakes or accelerates, DISTRONIC can initiate the following measures for vehicle deceleration or vehicle acceleration:

The brake application takes place by means of hydraulic pressure controlling in the wheel brake cylinder by the traction system hydraulic unit according to the current vehicle status. The Electronic Stability Program control unit (ESP) (N30/4) evaluates a range of variables for this purpose such as the required braking torque.

In order to prevent a possible collision, the driver must fully depress the brake pedal if it is apparent to him that the initiated measures are insufficient.

If the vehicle driving immediately ahead accelerates again, the engine torque is increased and the vehicle also accelerates. The increase in engine torque is dependent on the ascent or the descent involved, among other things.

The maximum (positive) acceleration depends on the selected drive program (with code G42 (7G-TRONIC PLUS) or with code G43 (9G-TRONIC)).

The driver can still accelerate the vehicle by pressing the accelerator pedal module (A68) (e.g. to overtake). Automatic acceleration is disabled for as long as the driver is pressing the accelerator pedal module (A68). The "DISTRONIC passive" message appears on the display (A1p13). If the automatic distance control requires a higher acceleration than the driver prescribes, the driver request is overlaid by the request for automatic distance control and the "DISTRONIC passive" message goes off.

The electric controller unit for Active Distance Assist DISTRONIC (B92/1) receives/transmits the following information/requests:

Input parameters:

Output parameters:

Automatic speed control

If the vehicle is in an active distance control and the vehicle in front accelerates to over v = 200 km/h (120 mph) or leaves the radar sensor system detection range, the automatic distance control automatically switches to automatic speed control.

The electric controller unit for Active Distance Assist DISTRONIC (B92/1) receives/transmits the following information/requests:

Input parameters:

Output parameters:

Going back into a lane/person in the front regulation

If the vehicle driving immediately ahead turns off and there is another vehicle in front, the system only switches over to the new target vehicle if it is moving. The system does not operate for stationary objects unless a preceding vehicle is tracked to a standstill.

If while driving a vehicle turns in front within the safe distance to the vehicle driving immediately ahead, the distance to this new vehicle is regulated. If the vehicle is in automatic speed control and a vehicle tuns onto the lane driven in this vehicle is registered as the vehicle driving immediately ahead.

If the distance to the vehicle moving into the lane is below the preselected value, DISTRONIC brakes the vehicle. If the requested braking power is not sufficient, a visual warning and a warning tone are output and the driver has to depress the brake pedal.

DISTRONIC is thereby deactivated. The driver is notified of this by means of an intermittent warning tone output via the instrument cluster speaker (H4/61) and a warning display on the display (A1p13) of the instrument cluster (A1). The driver can subsequently reactivate the DISTRONIC.

IMPORTANT The negative acceleration (deceleration) is limited to approx. a = 4.0 m/s2 of the maximum possible braking power.

The electric controller unit for Active Distance Assist DISTRONIC (B92/1) receives/transmits the following information/requests:

Input parameters:

Output parameters:

Automated Stop Vehicle

In an active DISTRONIC, the vehicle will follow the vehicle driving in front to a standstill. The deceleration here is due to the service brake. The service brake also secures a stationary vehicle against rolling away.

After a defined time period the electric parking brake is also activated (standstill control safety strategy).

IMPORTANT Securing the vehicle using DISTRONIC is no substitute for securing the vehicle during parking.

The electric controller unit for Active Distance Assist DISTRONIC (B92/1) receives/transmits the following information/requests:

Input parameters:

Output parameters:

The following traffic situations show the limits of the DISTRONIC:

Obstacles and stationary vehicles

The DISTRONIC does not brake for obstacles or stationary vehicles which were not previously registered as the target object. If, for example, the detected vehicle turns off and there is an obstacle or stationary vehicles behind it, no automatic intervention by the brake system occurs.

G16501029Courtesy of MERCEDES-BENZ USA

Curves, curved entrances and exits

The DISTRONIC can only provides limited detection of vehicles in curves. One's own vehicle can then brake unexpectedly or late.

G16501030Courtesy of MERCEDES-BENZ USA

Vehicles moving across in front of one's own vehicle

DISTRONIC may detect vehicles in cross traffic by mistake. For an activated distance control the vehicle can start off unintended, (e.g. at a traffic light with cross-traffic).

G16501031Courtesy of MERCEDES-BENZ USA

Offset driving style

The DISTRONIC may not be able to detect vehicles driving displaced to one side. The distance to the vehicle in front becomes too small.

G16501032Courtesy of MERCEDES-BENZ USA

Lane change by other vehicles

The DISTRONIC does not yet detect the vehicle moving into the lane. The distance to the vehicle moving into the lane becomes too small.

G16501033Courtesy of MERCEDES-BENZ USA

Narrow vehicles

DISTRONIC PLUS does not detect the vehicle in front at the edge of the carriageway because of its narrow width. The distance to the vehicle in front becomes too small.

G16501034Courtesy of MERCEDES-BENZ USA
  Detailed information     
  Overall network (GVN), detailed information Model 447 except electric vehicles with code XM7 (facelift II) GF00.19-S-0020-01B
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