Cruise Control (CC), Function - GF30.30-P-0001LFM
Model 217, 222
as of model year 2018
Shown on model 217, 222
Function requirements, general
- Engine running or drivetrain operational
- Gear range "D" engaged
- Vehicle speed:
- Vehicle speed v ≥ 30 to 250 km/h or maximum design speed (except code 23P (Driving Assistance Package)) or with deactivated distance control (with code 23P (Driving Assistance Package))
- Vehicle speed v ≥ 30 to 210 km/h (with code 23P (Driver Assistance Package) and 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.
For vehicles with code 23P (Driving Assistance Package), the Mercedes-Benz Intelligent Drive control unit transmits the function-relevant requests to the Electronic Stability Program control unit via the suspension FlexRay. The Electronic Stability Program control unit processes these and prioritizes them according to the respective own evaluated parameters.
Multifunction steering wheel cruise control buttons, shown: model 222 except code L5C (multifunction sports steering wheel in nappa leather), ECE left-hand drive vehicle
The cruise control is activated with the stored specified speed using the cruise control resume switch (top switch position). If the cruise control is already activated, the current speed limit will be adopted as the new specified speed. The cruise control is switched off by pushing the cruise control resume switch downwards.
The specified speed can be altered in steps of v = 1 km/h or v = 10 km/h using the cruise control switch.
Actuation up to the actuation point increases the set speed by v = 1 km/h. If the switch is pressed beyond the actuation point then the specified speed increases each time by v = 10 km/h. If the switch is held at or beyond the actuation point, the specified speed is changed every t = 0.6 s.
The following input factors are evaluated to implement the function:
- Operating condition of engine/drivetrain (function requirements)
- Engaged gear range (function requirements)
- Vehicle speed
- Driver request via cruise control switch and cruise control resume switch
- Accelerator pedal position
Operating condition for engine/drivetrain:
The CDI control unit or the ME control unit sends the "engine running" or "powertrain operational" signal via the engine CAN, powertrain control unit, and suspension FlexRay to the Electronic Stability Program control unit, and for vehicles with code 23P (Driving Assistance Package) also to the Mercedes-Benz Intelligent Drive control unit.
The CDI control unit or the ME-SFI [ME] control unit, amongst other things, coordinates acceleration, deceleration or switching requirements. In doing so it prioritizes requests according to their relevance, while taking account of the additional variables such as the charge level of the high voltage on-board electrical system, the operating status of the ancillaries or requests from comfort systems such as the automatic climate control.
Engaged gear range:
Information on the engaged drive range is sent by the fully integrated transmission control unit via the drive CAN, powertrain control unit, and the suspension FlexRay to the Electronic Stability Program control unit, and in vehicles with code 23P (Driving Assistance Package) also to the Mercedes-Benz Intelligent Drive control unit.
Vehicle speed:
The vehicle speed is calculated by the Electronic Stability Program control unit from the wheel speeds.
For vehicles with code 23P (Driving Assistance Package), the Electronic Stability Program control unit additionally transmits the wheel speed signals to the Mercedes-Benz Intelligent Drive control unit via the suspension FlexRay.
Driver request via cruise control switch and cruise control resume switch:
The cruise control switch and the cruise control resume switch send driver requests via the steering wheel electronics, steering wheel CAN, steering column tube module control unit, and suspension FlexRay to the Electronic Stability Program control unit, and in vehicles with code 23P (Driving Assistance Package) also to the Mercedes-Benz Intelligent Drive control unit.
Accelerator pedal position:
Information on the accelerator pedal position is sent by the powertrain control unit via the suspension FlexRay to the Electronic Stability Program control unit, and in vehicles with code 23P (Driving Assistance Package) also to the Mercedes-Benz Intelligent Drive 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 23P (Driving Assistance Package), 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 suspension FlexRay, powertrain control unit, and the drive CAN to the CDI control unit or the ME control unit.
For vehicles with code 23P (Driving Assistance Package), the Mercedes-Benz Intelligent Drive control unit sends the "increase/reduce drive torque" request to the Electronic Stability Program control unit via the suspension FlexRay. The Electronic Stability Program control unit processes this and transmits it according to its priority via the chassis FlexRay, powertrain control unit and engine CAN to the CDI control unit or the ME-SFI [ME] control unit.
The CDI control unit or the ME-SFI [ME] control unit implements this request.
Engage targeted gear (downshift or upshift):
For vehicles without code 23P (Driving Assistance Package), the Electronic Stability Program control unit evaluates the input factors and other driving dynamic requests, and transmits the "engage requested gear" request via the suspension FlexRay, powertrain control unit, and drive CAN to the fully integrated transmission control unit.
For vehicles with code 23P (Driving Assistance Package), the Mercedes-Benz Intelligent Drive control unit sends the "engage requested gear" request to the Electronic Stability Program control unit via the suspension FlexRay. The Electronic Stability Program control unit processes this and transmits it according to its priority via the chassis FlexRay, powertrain 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 23P (Driving Assistance Package), the Electronic Stability Program control unit evaluates the input factors and actuates the traction system hydraulic unit accordingly.
For vehicles with code 23P (Driving Assistance Package), the Mercedes-Benz Intelligent Drive control unit sends the "increase/reduce braking torque" request to the Electronic Stability Program control unit via the suspension FlexRay. 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.
Model 222.004/057/104/157/163/173
as of model year 2018
For model the kinetic energy is converted within defined limits into electrical energy (regenerative braking). If the required braking torque exceeds the deceleration through regenerative braking, the regenerative braking system control unit also actuates Electronic Stability Program control unit and the traction system hydraulic unit and therefore the service brake.
Cruise control encompasses the following subfunctions:
- Function sequence for automatic speed control
- Function sequence, variable speed limiter
Additional automatic speed control function requirements
- Cruise control selected via cruise control switch (except code 494 (USA version))
- Electronic Stability Program (ESP®) not switched to passive mode
Function sequence for automatic speed control
Through actuation of the cruise control resume switch, the last stored specified speed is applied, provided a specified speed has been stored since the last engine start. If no set speed was stored, the current vehicle speed is set as the set speed. The target speed is displayed in the IC.
For vehicles without code 23P (Driving Assistance Package), the Electronic Stability Program control unit transmits the set speed (specified speed) to the instrument cluster via the suspension FlexRay, electronic ignition lock control unit, and user interface CAN. For vehicles without code 23P (Driving Assistance Package), the Mercedes-Benz Intelligent Drive control unit transmits the set speed (specified speed) to the instrument cluster via the suspension FlexRay, electronic ignition lock control unit, and user interface CAN.
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:
- Push the cruise control resume switch downwards
- Switchover to the variable speed limiter
- Depressing the brake pedal
- Active regulation of the ESP® or ESP® switched off
- 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, variable speed limiter
The DTCO has the following subfunctions:
- Function sequence for variable speed limiter (except code 494 (USA version))
- Function sequence for permanent limiter
Additional function sequence for variable speed limiter (except code 494 (USA version))
- Variable limiter selected via limiter switch and Distance Pilot switch
Function sequence for variable speed limiter (except code 494 (USA version))
The variable speed limiter 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 the driver switches to the variable limiter on the steering wheel, the automatic speed control is deactivated.
The following events deactivate the variable speed limiter:
- Press the limiter and Distance Pilot button (except code L5C (multifunction sports steering wheel in nappa leather))
- Press the limiter and Distance Pilot button (with code L5C (multifunction sports steering wheel in nappa leather))
- Kickdown (accelerator pedal pressed by > 90 % and driven speed v < 20 km/h removed from the set maximum speed)
- ESP switched to passive mode
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 permissible maximum speed takes place in the menu "Settings", "Vehicle" and "Limitation (winter tires)" in the head unit. For navigation in the operating menu the following options are available:
- With code 448 (Touchpad) navigation can be operated using the Audio/COMAND control panel. The Audio/COMAND control panel sends the corresponding control signals (except code 446 (Touchpad only)) to the head unit via the telematics CAN.
- With code 446 (Touchpad only) or code 448 (Touchpad), the navigation takes place with the Touchpad. The touchpad (with code 446 (Touchpad only)) or code 448 (Touchpad)) transmits the respective control signals via the telematics CAN to the head unit.
- The navigation can occur over voice control. The driver FSE microphone is directly read in by the head unit.
- The navigation can occur over the head unit finger navigation pad and the "Back" button on the steering wheel. The corresponding operation signals are sent by the head unit finger navigation pad and the "Back" button over the steering wheel electronics, steering wheel CAN, steering column tube module control unit, suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the head unit.
- With code 448 (Touchpad) the control menu can be activated with the "CAR" button on the Audio/COMAND control panel. The status of the "CAR" button is sent by the Audio/COMAND control panel over the telematics CAN to the head unit.
With code 446 (Touchpad only) the control menu can be activated using the "CAR" button on the lower control panel. The status of the "CAR" button is sent to the head unit by the lower control panel via the LCP-LIN, touchpad (with code 446 (touchpad only)), and the telematics CAN.
For vehicles without code 23P (Driving Assistance Package), the head unit transmits the set maximum speed via the user interface CAN, electronic ignition lock control unit, and suspension FlexRay to the Electronic Stability Program control unit.
For vehicles with code 23P (Driving Assistance Package), the head unit sends the set maximum speed via the user interface CAN, electronic ignition lock control unit, and the suspension FlexRay to the Mercedes-Benz Intelligent Drive 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. The head unit transmits the set maximum speed via the user interface CAN, electronic ignition lock control unit and user interface CAN to the IC.
If the maximum speed was reached the following activities are started:
- Reduce drive torque
- Engage targeted gear (shift down)
- Raise braking torque
The permanent limiter also remains active for a switched off variable speed limiter.
| Electrical function schematic for cruise control (CC) | PE30.30-P-2051-97SEC | ||
| Overview of system components for driver assistance systems | GF54.00-P-9998LFM |