Cruise Control (CC), Function - GF30.30-P-0001FQM
MODEL 218
as of year 2015
Function requirements, general
- Engine running or drivetrain operational
- Gear range "D" engaged
- Vehicle speeds:
- Vehicle speed v > 30 km/h up to maximum the vehicle high speed (without code (233) DISTRONIC PLUS or for vehicles with code (233) DISTRONIC PLUS for a deactivated distance control)
- Vehicle speed v > 30 to 200 km/h (for code (233) DISTRONIC PLUS for an activated distance control)
Cruise control - general
The cruise control regulates the vehicle speed constantly and automatically to the desired speed set by the driver. To do this, the cruise control evaluates the driver's commands and the current driving condition.
The vehicles with code (233) DISTRONIC PLUS transmits the radar sensors control unit function-relevant requests via the chassis FlexRay, chassis gateway control unit and chassis CAN 1 to the Electronic Stability Program control unit.
The Electronic Stability Program control unit processes these and prioritizes them according to the respective own evaluated parameters.
Operation of cruise control using the CRUISE CONTROL lever
The cruise control is activated using the resume from memory switch. Here the last stored or momentary vehicle speed is set as the set speed. Using the switches "decelerate" and "set" and the switches "accelerate" and "set", the target speed can be altered in steps of v = 1 km/h or v = 10 km/h.
Actuation up to the actuation point increases the set speed by v = 1 km/h. If the switch is pressed beyond the actuation point, the target speed is altered in steps of v = 10 km/h. If the switch is held at or beyond the actuation point, the target speed is altered every t = 0.6 s.
The following input factors are evaluated to implement the function:
- Engine running or drivetrain operational (function requirements)
- Engaged gear range (function requirements)
- Vehicle speed
- Driver request via the cruise control lever
- Accelerator pedal position Engine running or drivetrain operational
The CDI control unit or the ME-SFI [ME] control unit sends the "Engine running" or "Drivetrain operational" signal via the engine CAN 1, to the Electronic Stability Program control unit and for vehicles with code (233) DISTRONIC PLUS also via the chassis CAN 1, chassis gateway control unit and chassis FlexRay to the radar sensors control unit.
Engaged gear range:
The fully integrated transmission control unit sends information about the gear range via the drive train CAN, CDI control unit or ME-SFI [ME] control unit and chassis CAN 1 to the Electronic Stability Program control unit and for vehicles with code (233) DISTRONIC PLUS also via the drive train CAN, CDI control unit or ME-SFI [ME] control unit, chassis CAN 1, chassis gateway control unit and chassis FlexRay to the radar sensors control unit.
Vehicle speed:
The vehicle speed is calculated by the Electronic Stability Program control unit from the wheel speeds.
The vehicles with code (233) DISTRONIC PLUS transmits the Electronic Stability Program control unit also transmits the wheel speed signals via the chassis CAN 1, chassis gateway control unit and chassis FlexRay to the radar sensors control unit.
Driver request via the cruise control lever:
The driver request over the CC lever are directly read in by the steering column tube module control unit. The steering column tube module control unit transm its the control signals of the CC lever via the chassis CAN 1 to the Electronic Stability Program control unit and, for vehicles with code (233) DISTRONIC PLUS, also via chassis CAN 1, chassis gateway control unit and chassis FlexRay to the radar sensors control unit.
Accelerator pedal position:
The CDI control unit or ME-SFI [ME] control unit transmits information about the accelerator pedal position via chassis CAN 1 to the Electronic Stability Program control unit and for vehicles with code (233) DISTRONIC PLUS also via chassis CAN 1, chassis gateway control unit and chassis FlexRay to the radar sensors control unit.
The following initial parameters (requests) are issued to implement the function:
- Increase/reduce the drive torque
- Engage targeted gear (back or upshift)
- Increase/reduce the braking torque
Increase/reduce the drive torque
For vehicles without code (233) DISTRONIC PLUS the Electronic Stability Program control unit evaluates the input factors along with additional driving dynamic requests and sends the "Increase/reduce drive torque" request via the chassis FlexRay, powertrain control unit and the drive train CAN and engine CAN to the CDI control unit or the ME-SFI [ME] control unit.
For vehicles with code (233) DISTRONIC PLUS the radar sensors control unit transmits the request "increase/reduce drive torque" via the chassis FlexRay, chassis gateway control unit and chassis CAN 1 to the Electronic Stability Program control unit. The Electronic Stability Program control unit processes this, prioritizes this and transmits it according to its priority via chassis CAN 1 to the CDI control unit or the ME-SFI [ME] control unit.
Engage targeted gear:
For vehicles without code (233) Adaptive cruise control the Electronic Stability Program control unit evaluates the input factors as well as further driving dynamic requests and transmits the request "Engage targeted gear" via chassis CAN 1, CDI control unit or ME-SFI [ME] control unit and drive train CAN to the fully integrated transmission control unit.
For vehicles with code (233) DISTRONIC PLUS the radar sensors control unit transmits the request "Engage targeted gear" via the chassis FlexRay, chassis gateway control unit and chassis CAN 1 to the Electronic Stability Program control unit. The Electronic Stability Program control unit processes this and transmits it, according to its priority, via chassis CAN 1, CDI control unit or ME-SFI [ME] control unit and drive train CAN to the fully integrated transmission control unit.
This request is to be understood as a shift recommendation.
Downshifting or upshifting of the automatic transmission takes place autonomously by the fully integrated transmission control unit dependent on the current operating condition.
Raise/reduce braking torque:
For vehicles without Code (233) DISTRONIC PLUS the Electronic
Stability Program control unit evaluates the input factors and actuates the traction system hydraulic unit appropriately.
For vehicles with code (233) DISTRONIC PLUS the radar sensors control unit transmits the request "increase/reduce braking torque" via the chassis FlexRay, chassis gateway control unit and chassis CAN 1 to the Electronic Stability Program control unit. The Electronic Stability Program control unit evaluates these and actuates the traction system hydraulic unit appropriately.
The traction system hydraulic unit reacts by increasing or reducing the braking torque.
Cruise control encompasses the following subfunctions:
- Function sequence for automatic speed control
- Function sequence for SPEEDTRONIC
Additional automatic speed control function requirements
- Cruise control selected using SPEEDTRONIC switch (without code (494) USA version) (SPEEDTRONIC LED off)
- Electronic Stability Program (ESP®) not passively switched (except engine 157)
- ESP® not switched into "SPORT HANDLING MODE" (for engine 157)
Function sequence for automatic speed control
Through actuation of the "Resume from memory" switch the last set speed stored is applied, provided a set speed was stored since the last engine start. If no set speed was stored, the current vehicle speed is set as the set speed. The setting speed is shown in the multifunction display of the IC.
For vehicles without code (233) DISTRONIC PLUS the Electronic Stability Program control unit sends the set speed (target speed) via the chassis CAN 1, front SAM control unit and chassis CAN 2 to the IC. For vehicles with code (233) DISTRONIC PLUS the radar sensors control unit transmits the set speed (target speed) via the chassis FlexRay, chassis gateway control unit and chassis CAN 2 to the IC.
The driver also has the option to accelerate beyond the set target speed through actuation of the accelerator pedal (for example when overtaking). The set speed is regulated again after removal of the acceleration request (releasing the accelerator pedal).
The following events deactivate the automatic speed control:
- Operation of the OFF switch
- Switch over to the variable SPEEDTRONIC
- Depressing the brake pedal
- Active regulation of the ESP®
- Speed v < 25 km/h
- Gear range not "D"
The following activities are started in order to reach or maintain the set speed:
- Increase/reduce the drive torque
- Engage targeted gear (back or upshift)
- Increase/reduce the braking torque
Function sequence for SPEEDTRONIC
The SPEEDTRONIC comprises the following subfunctions:
- Function sequence for variable SPEEDTRONIC (without code (494) USA version)
- Function sequence for permanent limiter
Additional function requirements for variable SPEEDTRONIC (without code (494) USA version)
- Variable SPEEDTRONIC selected with SPEEDTRONIC switch (SPEEDTRONIC LED lights up)
The steering column tube module control unit actuates the SPEEDTRONIC LED directly.
Function sequence for variable SPEEDTRONIC (without code (494) USA version)
The variable SPEEDTRONIC can be used to limit the vehicle's maximum speed to a freely selectable value (e.g. v = 50 km/h in urban traffic). The driver can accelerate the vehicle up to the set limit. If the set limit was reached, the following activities are started:
- Reduce drive torque
- Engage targeted gear (shift down)
- Raise braking torque
If switching takes place on the variable SPEEDTRONIC on the CC lever, the automatic speed control is deactivated.
The following events deactivate the variable SPEEDTRONIC:
- Operation of the OFF switch
- Kickdown (accelerator pedal pressed by >90% and vehicle speed v <20 km/h away from selected maximum speed)
- ESP® passively engaged (except model 157)
- ESP® switched into "SPORT HANDLING MODE" (for engine 157)
Function sequence for permanent limiter
The maximum speed of the vehicle can be limited in steps of v = 10 km/h from v = 160 to 240 km/h. Adjustment of the maximum speed takes place in the menu "Settings", "Vehicle" and "Limitation (winter tires)" in the instrument cluster.
For vehicles without code (233) DISTRONIC PLUS the IC sends the set maximum speed (target speed) via the chassis CAN 2, front SAM control unit and chassis CAN 1 to the Electronic Stability Program control unit. For vehicles with code (233) DISTRONIC PLUS the IC transmits the set maximum speed via chassis CAN 2, chassis gateway control unit and chassis FlexRay to the radar sensors control unit.
Approximately v = 10 km/h before reaching the set maximum speed a message appears in the instrument cluster multifunction display that indicates a maximum speed limitation. The driver can accelerate the vehicle up to the set maximum speed.
If the maximum speed was reached the following activities are started:
- Reduce drive torque
- Engage targeted gear (shift down)
- Reduce braking torque
| Electrical function schematic for cruise control (CC) | MODEL 218 as of model year 2015 without CODE 233 (DISTRONIC PLUS) | PE30.30-P-2051-97XAC | |
| MODEL 218 as of model year 2015 with CODE 233 (DISTRONIC PLUS) | PE30.30-P-2051-97XAD | ||
| Overview of system components for driver assistance systems | GF54.00-P-9998FQM |