Interfaces

Active Cruise Control communicates with the partner systems exclusively by means of data exchange over the bus systems.

The interface is monitored by transmission of special monitoring variables, by checking the messages for plausibility and by timeouts.

Motor control

The interface serves to communicate the torque request to the engine management system. In addition, the relevant engine data are transmitted to Active Cruise Control.

Variant recognition

The engine control module is automatically coded as soon as the engine management system receives a torque request for the first time from Active Cruise Control. The standard coding for cruise control is overwritten.

Engine management --> Active Cruise Control

The following signals are transmitted:

• Crankshaft torque
  
• Moment of friction including auxiliaries
  
• Full load value
  
• Desired torque without control intervention
  
• Engine speed
  
• Status, cruise control
  
• Accelerator pedal position
  
• Status, inertia fuel shutoff
  

Active Cruise Control --> engine management

The current torque request is transmitted.

Dynamic Stability Control

The interface serves to communicate the brake request to Dynamic Stability Control. In addition, the brake status data and driving dynamics data are transmitted to Active Cruise Control.

Variant recognition

Dynamic Stability Control is automatically coded as soon as it receives a deceleration request for the first time from Active Cruise Control.

Dynamic Stability Control --> Active Cruise Control

The following signals are transmitted:

• Accepted current deceleration request
  
• Driving dynamics variables
  
  • Wheel speeds
    
  • Wheel tolerances
    
  • Status, tolerance adjustment
    
  • Rotational speed
    
  • Longitudinal acceleration
    
  • Lateral acceleration
    
  • Driving situation
    
  • Reference speed
    
• Current brake status (ABS, ASC, DSC, hydraulic brake assist, engine drag torque control, electronic brake-force distribution)
  
• Status, brake actuation (brake light switch + braking pressure)
  

Active Cruise Control --> Dynamic Stability Control

The current deceleration request is transmitted.

Transmission Control

The interface serves to communicate the current control status to the transmission control. In control mode, special gearshift maps are used which increase gearshift comfort. The safety functions are not affected.

Variant recognition

Not required.

Transmission control --> Active Cruise Control

The following signals are transmitted:

• Gear currently selected
  
• Current traction force at the wheels
  

Active Cruise Control --> transmission control

The current operating state is transmitted. This is used to select the gearshift maps.

Instrument cluster

The instrument cluster assumes all the display functions for Active Cruise Control. System malfunctions are output via the Check Control display. A specific gong also sounds for specific displays.

Variant recognition

The instrument cluster is automatically coded as soon as it receives a display request for the first time from Active Cruise Control.

Instrument cluster --> Active Cruise Control

The following signals are transmitted:

• Speedometer scaling, miles/kilometers (for initialization only)
  
• Outside temperature
  
• Kilometer reading
  
• Speed indication
  

Active Cruise Control --> instrument cluster

The following signals are transmitted:

• Desired speed
  
• ”Object detected” indication
  
• Distance selection indication
  
• Driver takeover control request
  
• Check Control messages:
  

Controller

The information for radar deactivation is communicated.

Variant recognition

Not required.

Controller --> Active Cruise Control

A deactivation request can be transmitted by the controller.

Active Cruise Control --> controller

An acknowledgment signal is transmitted.

Car Access System

The information on terminal 15 status is communicated.

Trailer Module

The information as to whether a trailer is hitched up is communicated.

Steering column switch center

Actuation of the steering column lever is transmitted. The current steering angle signal is also communicated.

Parking brake

Application of the parking brake is transmitted.