Distronic Plus With Steer Assist And Stop & Go Pilot Function - GF30.30-P-0017LF
Model 217, 222
up to model year 2018
with code 266 (DISTRONIC PLUS with Cross-Traffic Assist (DTR+Q))
Function requirements, general
- No undervoltage or overvoltage
- "ADTR_AVL" (Advanced DISTRONIC PLUS) programmed in electronic ignition lock control unit
- Engine running or drivetrain operational
- Parking brake not operated
- Gear range "D" engaged (vehicle not in backward movement)
- Vehicle speed v = 0 to 200 km/h or v = 200 to 0 km/h
- The soiling and function test of the long range radar has been completed successfully
Object recognition (e.g. vehicle moving directly ahead) via the radar sensor system is based on the radar measuring procedure. The front long range radar sensor and the front bumper radar sensors run a contamination and function test after each engine start to ensure that they are functioning correctly. The function test requires an object in the respective detection area that is used as a reference object. If a malfunction is established or if there are no objects in the detection area, the DISTRONIC PLUS cannot be activated. The radar sensors control unit receives the signals of the front bumper radar sensors via the radar-CAN 1 and sends them over the chassis FlexRay to the front long range radar sensor. The front long range radar sensor evaluates them in combination with its own signals and, when all the radar sensors are functioning correctly, sends the "Radar sensor system operational" status via chassis FlexRay to the radar sensor control unit.
- Electronic Stability Program (ESP®) not passively switched (except engine 157, 279)
- ESP® not switched into "SPORT HANDLING MODE" (for engine 157, 279)
- No active ESP® intervention recognized (vehicle not in sliding movement)
- Standstill control, enable issued (driver door/driver belt buckle and front passenger door closed)
DISTRONIC PLUS with Steer Assist and Stop & Go Pilot, general point
The DISTRONIC PLUS automatically controls the speed and the distance to a vehicle driving ahead in accordance with the driver's request by braking when necessary and accelerating again if possible. The distance and speed control is carried out by the radar sensors control unit. In order to do this, the radar sensors control unit actively intervenes in the engine management and/or the brake system.
In stop and go traffic the DISTRONIC PLUS brakes vehicle automatically (if necessary through to a standstill). Once the traffic situation permits it again, DISTRONIC PLUS automatically accelerates the vehicle to the set target speed, and thus relieves the driver of tiring routine tasks (e.g. frequent starting off and braking during stop-and-go or convoy driving).
If DISTRONIC PLUS recognizes that more extensive braking is necessary (e.g. traffic pulling in, a stationary obstacle), the DISTRONIC warning lamp in the instrument cluster lights up, and an intermittent alarm tone sounds. Both require the driver to proceed with increased caution and to possibly also brake himself. If the driver reacts to the warning tones and brakes, he/she is supported here by the Brake Assist. This calculates the required brake force amplification according to the situation. A threatening accident can be prevented under certain circumstances or at least one can mitigate its consequences. However, if the driver does not react to the warning tones, the PRE-SAFE® brake initially initiates (in addition to optical warnings and warning tones) an automated partial braking and subsequently a maximum full-stop braking.
If the DISTRONIC PLUS is switched off, the situation directly in front of the vehicle is still detected and evaluated. In dangerous situations warnings are given, as described above, or there is autonomous braking.
The Steer Assist supports the driver in maintaining directional stability. In doing this, Steer Assist orients itself over the whole vehicle speed range towards traffic lane markings, and also towards preceding vehicles at lower speeds, e.g. in the traffic jam vehicle following function. The vehicle stays in its lane and unintentional movement towards the lane markings is prevented. The Steer Assist does not relieve the driver of his/her task of keeping the vehicle in the lane. It serves more to relieve the load and therefore to facilitate the resultant increase in comfort. Assistance is also only provided within defined limits, i. e. no assistance can be provided for large steering angles at slow speeds, e.g. caused by driving on roads going over passes.
The following subfunctions of DISTRONIC PLUS are described in a separate document:
- Automatic speed control
- Variable SPEEDTRONIC (except code 494 (USA version))
- Permanent limiter
Operation:
The DISTRONIC PLUS is operated via the CRUISE CONTROL lever. The steering column tube module control unit reads in the control signals of the cruise control lever directly and sends this via suspension FlexRay to the radar sensors control unit.
The menu settings in the instrument cluster can be used to switch the distance display on and off.
Design of the cruise control lever
Upon operation of the CC lever the distance to the vehicle driving immediately ahead is displayed in the multifunction display for t = 5 s. Through selection of the operating level "DISTRONIC PLUS" in the menu "Assistance" the distance graphic is shown permanently. Display of the distance graphic can be switched on or off independently of the activity of the automatic distance control. The distance to the vehicle in front can be set via the DISTRONIC control in seven stages between approx. t = 1.0 and 2.0 s.
The radar sensors control unit evaluates the following input factors:
- Signal "Engine running" or "Drivetrain operational" (function requirements)
- Status of parking brake (function requirements)
- Engaged gear range (function requirements)
- Driver request via the cruise control lever (function requirements)
- Vehicle speed/direction of travel/acceleration
- Status of ESP® (function requirements)
- "Steer Assist" status (Steer Assist only)
- Status of the electric power steering (only Steer Assist)
- Object detection by the front bumper radar sensors
- Object detection by the front long range radar sensor
- Object detection by the stereo multifunction camera (Steer Assist only)
- Lane data (Steer Assist only)
- Steering torque of driver and wheel angle (Hands-Off Detection status) (Steer Assist only)
- Global Positioning System (GPS) signals/signals for traffic assessment
- Engine drive torque
- Brake torque
- Tire pressure monitoring status (with CODE 475 (Tire pressure monitoring) or CODE 477 (Tire pressure loss warning) (Steer Assist only))
- Trailer recognition (with code 550 (Trailer hitch)) (Steer Assist only)
- Acceleration/yaw rate
- Transmission mode status
- Steering wheel angle
- Driver request to overtake (sets the turn signals on the combination switch)
- Accelerator pedal position
- Brake pedal position
Signal "Engine running" or "Drivetrain operational":
The CDI control unit or the ME-SFI [ME] control unit sends the "Engine running" or "Drivetrain operational" signal to the radar sensors control unit via the drive train CAN, powertrain control unit and chassis FlexRay.
Parking brake status:
The electric parking brake control unit transmits the status of the parking brake via the periphery CAN, electronic ignition lock control unit and suspension FlexRay to the radar sensors control unit.
Engaged gear range:
The fully integrated transmission control unit sends information about the selected gear range via drive train CAN, powertrain control unit and suspension 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 transmits the control signals from the CRUISE CONTROL lever via the suspension FlexRay to the radar sensors control unit.
Vehicle speed/direction of travel/acceleration:
The vehicle speed is calculated on the basis of the wheel speeds. The direction of travel is defined by the wheel rotation direction, the acceleration by the increase in the wheel rotation speed. The Electronic Stability Program control unit transmits the respective information via the chassis FlexRay to the stereo multifunction camera (Steer Assist only) and the radar sensors control unit.
ESP® status:
The Electronic Stability Program control unit sends the status of the Electronic Stability Program® via the suspension FlexRay to the radar sensors control unit.
"Steer Assist" status:
The Steer Assist can be switched on or off by pressing the Steer Assist button on the driver side instrument panel button group. The front SAM control unit reads in the status of the Steer Assist button via the instrument panel LIN and sends this via interior CAN, electronic ignition lock control unit and suspension FlexRay to the radar sensors control unit. The status of Steer Assist is displayed to the driver i.e. through the activation or deactivation of the LED in the Steer Assist button. The radar sensors control unit sends the corresponding request via chassis FlexRay, the electronic ignition lock control unit and interior CAN to the front SAM control unit. The front SAM control unit actuates the LED in the Steer Assist button via the instrument panel LIN.
After being switched on or off, the message "Steer Assist on/off" is displayed for t = 5 s in the instrument cluster.
Status of the electric power steering (only Steer Assist)
Information about the status of the electric power steering is transmitted by the electrical power steering control unit via the chassis FlexRay to the radar sensors control unit.
Object detection by the front bumper radar sensors:
The front bumper radar sensors operate according to the short pulse principle, and have a maximum range of s = 30 m. The front bumper radar sensors register objects in the short range area and send the data via the radar CAN 1 to the radar sensors control unit.
Object detection by the front long range radar sensor:
The front long range radar sensor monitors the traffic area in front of the vehicle up to a distance of s = 200 m in a corridor of ∠ = 18°. Objects up to a distance of s = 0 to 60 m are detected in a corridor of ∠ = 60°.
The front long range radar sensor operates according to the pulse modulated Doppler principle, which enables the distances and speeds of individual objects (e.g. vehicles) to be measured independently of each other. The front long-range radar sensor sends corresponding data via chassis FlexRay to the radar sensors control unit.
Object detection by the stereo multifunction camera (Steer Assist only):
The stereo multifunction camera consists of two high-resolution mono cameras and an integrated control unit. The laterally offset location of the two mono cameras creates a difference in perspective (parallax displacement) between the left and right optical path. The distance to the object ahead and other variables such as the height thereof are calculated on the basis of the differences between the image data.
The stereo multifunction camera records vehicles in the same lane under the following conditions:
- Preceding vehicle in detection range s ≥ 1 to 40 m (speed-dependent)
- Width of preceding vehicle s ≥ 1.30 to 3.20 m
- Vehicle center axis offset from preceding vehicle s ≤ 35 cm (at start of control)
- Vehicle speed > 0 to 60 km/h
- No lane change (turn signal not set)
Stereo multifunction camera object detection
The control unit integrated in the stereo MFK evaluates image data from the two mono cameras, processes it and transmits appropriate data via the chassis FlexRay to the radar sensors control unit. The radar sensors control unit compares this with the signals from the radar sensor system.
Lane data (Steer Assist only):
The stereo multifunction camera records pictures of the lane markings on the road regularly with a fixed sampling rate. The integrated control unit calculates a lane from the picture sequences and the measurements resulting from the pictures of the road markings. The stereo multifunction camera sends the lane data via the chassis FlexRay to the radar sensors control unit.
Stereo multifunction camera lane recording
Detailed information about the lane recognition is available in a separate document.
Steering torque of driver and wheel angle (Hands-Off Detection status) (Steer Assist only):
The electric power steering torque sensor records the steering torque applied by the driver and the wheel angle. The electrical power steering control unit reads in the signals from the electric power steering torque sensor directly and sends these via the suspension FlexRay to the radar sensors control unit. On the basis of these values, the radar sensors control unit determines whether and at which time intervals the driver is making steering movements (Hands-Off Detection).
GPS signals/signals for traffic assessment:
The COMAND controller unit evaluates the received GPS data utilizing further information for the traffic assessment, and sends corresponding information via the user interface CAN, electronic ignition lock control unit and the chassis FlexRay to the radar sensors control unit.
Engine drive torque:
The CDI control unit or the ME-SFI [ME] control unit transmits information about the currently available engine torque to the CDI control unit or ME-SFI [ME] control unit via the drive train CAN, powertrain control unit and the chassis FlexRay to the radar sensors control unit.
Braking torque:
The Electronic Stability Program control unit transmits information about the currently applied braking torque via the suspension FlexRay to the radar sensors control unit.
Tire pressure monitoring status (with CODE 475 (Tire pressure monitoring) or CODE 477 (Tire pressure loss warning) (Steer Assist only)):
Vehicles with CODE 475 (Tire pressure monitor):
The tire pressure monitor control unit sends information on the respective tire pressure to the radar sensors control unit over the user interface CAN, electronic ignition lock control unit and chassis FlexRay.
Vehicles with code 477 (Tire pressure loss warning):
The tire pressure is determined using the rolling circumference. The tire pressure loss warning (RDW) system is functionally integrated in the Electronic Stability Program control unit. The Electronic Stability Program control unit transmits information about the tire pressure to the radar sensors control unit via the chassis FlexRay.
Trailer recognition status (with code 550 (Trailer hitch)) (Steer Assist only):
When a trailer is detected, the trailer recognition control unit sends the "Trailer detected" status to the radar sensors control unit over the interior CAN, electronic ignition lock control unit and chassis FlexRay.
Acceleration/yaw rate:
The acceleration/turn rate is detected by the yaw rate sensor for lateral and longitudinal acceleration. The yaw rate sensor for lateral and longitudinal acceleration transmits corresponding values to the stereo multifunction camera (Steer Assist only) and the radar sensors control unit via the dynamics CAN, Electronic Stability Program control unit and suspension FlexRay.
Transmission mode status:
The driver can influence the vehicle's acceleration behavior by selecting the transmission mode using the transmission mode button. The audio/COMAND control panel directly reads in the status of the transmission mode button and sends it via the telematics CAN, COMAND controller unit, user interface CAN, electronic ignition lock control unit, suspension FlexRay, powertrain control unit and drive train CAN to the fully integrated transmission control unit.
The fully integrated transmission control unit transmits information about the transmission mode via the drive train CAN, the powertrain control unit and the chassis FlexRay to the radar sensors control unit.
Steering wheel angle:
The steering angle is recorded by the steering wheel angle sensor. The steering column tube module control unit directly reads in the signals of the steering wheel angle sensor and sends information to the radar sensors control unit over the suspension FlexRay.
Driver request to overtake (sets the turn signals on the combination switch)
The steering column tube module control unit reads in the switch position of the combination switch directly and transmits this via the chassis FlexRay to the stereo multifunction camera (Steer Assist only) and the radar sensors control unit.
Accelerator pedal position:
The CDI control unit or the ME-SFI [ME] control unit transmits information about the accelerator pedal position to the radar sensors control unit via the drive train CAN, powertrain control unit and the chassis FlexRay.
Brake pedal position:
The Electronic Stability Program control unit sends this information about the brake pedal position to the radar sensors control unit via chassis FlexRay.
The radar sensors control unit emits the following initial parameters (requests):
- Status of the DISTRONIC PLUS (only for Steer Assist)
- Increase/reduce engine torque
- Engage targeted gear (back or upshift)
- Increase/reduce the braking torque
- Steering requests (Steer Assist only)
- Emit warning tones, system or warning messages
Status of the DISTRONIC PLUS (only for Steer Assist):
Information about the status of the DISTRONIC PLUS is transmitted by the radar sensors control unit via the suspension FlexRay to the electrical power steering control unit.
Raise/reduce engine torque:
The radar sensors control unit then transmits the request "Increase engine torque" or "Reduce engine torque" via suspension FlexRay to the Electronic Stability Program control unit. The Electronic Stability Program control unit processes this request and further driving dynamics requests and sends them according to their relevance over 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):
The radar sensors control unit transmits the request "Engage targeted gear" via the suspension FlexRay to the Electronic Stability Program control unit. The Electronic Stability Program control unit processes this request as well as further driving dynamics requests and transmits it according to its relevance via the suspension FlexRay, powertrain control unit and drive train CAN to the fully integrated transmission control unit. This request is however to be understood as a switching recommendation. Downshifting or upshifting of the A/T takes place autonomously itself by the fully integrated transmission control unit, dependent on the current operating condition.
Raise/reduce braking torque:
The radar sensors control unit then transmits the request "Increase braking torque" or "Reduce braking torque" via suspension FlexRay to the Electronic Stability Program control unit. The Electronic Stability Program control unit reacts by directly actuating the traction system hydraulic unit, which reacts by increasing or decreasing the braking torque according to the brake torque.
Steering requests (Steer Assist only):
The radar sensors control unit calculates the additive toothed rack force on the basis of factors such as the steering torque of the driver, the lateral acceleration, the vehicle speed and the object and lane data of the stereo multifunction camera, and transmits appropriate steering requests via the chassis FlexRay to the electrical power steering control unit. The electrical power steering control unit receives and checks the plausibility of the incoming steering requests and actuates the electric power steering actuator motor accordingly.
The additive toothed rack force is only available up to a certain threshold value dependent on the above-mentioned variables and thereby limits the characteristic of the steering power assistance.
Emit warning tones, system or warning messages
The radar sensors control unit sends the requests to issue warning tones, system or warning messages over the suspension FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster which issues the corresponding system or warning messages on the instrument cluster and which directly actuates the instrument cluster speaker.
The description of the DISTRONIC PLUS function takes place, as an example, in the following chronological sequence:
- Activate DISTRONIC PLUS and drive off automatically
- Automatic distance control
- Change of driving lane (overtaking)
- Convoy driving
- Interventions in the steering by the Steer Assist
- Automatic speed control
- Going back into a lane/person in the front regulation
- Passing over roundabouts, T intersections and freeway exit lane
- Automated Stop Vehicle
Activate DISTRONIC PLUS and drive off automatically
The following options are available for activating DISTRONIC PLUS:
- Using the "Resume from memory" switch on the cruise control lever, call up the last selected set speed (set speed v ≥ 30 km/h)
- Briefly operate accelerator pedal
The vehicle moves off and adapts its speed to the maximum speed of the vehicle immediately ahead up to the selected target speed. If there is no vehicle immediately ahead, the DISTRONIC PLUS functions like the CC.
Information about the CC is contained in a separate document.
For vehicles at a standstill a specified distance limit exists beyond which a stationary vehicle is no longer displayed.
Technical implementation
To do this the radar sensors control unit receives or transmits the following information or requests:
Input factors:
- Accelerator pedal position
- Driver request via the cruise control lever
- Object recognition
- Vehicle speed/acceleration
- Acceleration/yaw rate
- Brake pedal position
Initial parameters:
- Increase/reduce engine torque
- Engage targeted gear
- Emit warning tones, system or warning messages
Automatic distance control
Automatic distance control can only be activated while driving (v < 30 km/h) if a preceding vehicle has been detected. If the vehicle driving immediately ahead brakes or accelerates, the DISTRONIC PLUS can initiate the following measures for deceleration or acceleration of the vehicle:
- Increase/reduce engine torque
- Increase/reduce the braking torque
The brake application takes place by means of hydraulic pressure controlling in the wheel brake cylinder by the traction system hydraulic unit. To do this the Electronic Stability Program control unit assesses various variables such as the required braking torque.
Model 222.004/057/104/157/163
up to model year 2018
with code 266 (DISTRONIC PLUS with Cross-Traffic Assist (DTR+Q)) For model the kinetic energy is converted within defined limits into electrical energy (regenerative braking). If the requested braking torque exceeds the deceleration through recuperation (for example in a case of a emergency braking), the Electronic Stability Program control unit additionally actuates the traction system hydraulic unit and therefore the service brake.
The driver must press on the brake pedal is sees that the instigated measures are not adequate to avoid any possible collision.
If the driver does not intervene, an additional intervention by the brake system is made by the PRE-SAFE® brake.
Detailed information about autonomous braking is available in a separate document.
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 driver can influence the vehicle's acceleration behavior by selecting the transmission mode using the transmission mode button. The driver furthermore has the option of operating the accelerator pedal to accelerate the vehicle (e.g. when overtaking). The automatic acceleration is put out of action for as long a the driver uses the accelerator pedal. The multifunction display shows the "DISTRONIC passive" message.
Technical implementation
To do this the radar sensors control unit receives or transmits the following information or requests:
Input factors:
- Object recognition
- Vehicle speed/acceleration
- Acceleration/yaw rate
- Engine drive torque
- Accelerator pedal position
- Driver request via the cruise control lever
- Brake pedal position
Initial parameters:
- Increase/reduce engine torque
- Increase/reduce the braking torque
- Engage targeted gear
- Emit warning tones, system or warning messages
Change of driving lane (overtaking)
For overtaking at a speed of more than v = 70 km/h) the vehicle is also accelerated automatically. To do this the driver must initiate the overtaking maneuver by setting the turn signal. In as far as the automatic distance control is activated, the radar sensors control unit recognizes the intention of the driver to overtake and accelerates the vehicle.
If there is no vehicle in the radar sensor system detection range after overtaking, the automatic distance control goes into automatic speed control. If a vehicle driving immediately ahead is detected after an overhauling process the automatic speed control goes back into automatic distance control.
The overtaking maneuver is broken off in the following situations:
- Risk of a collisions with the currently detected vehicle
- Risk of collision with a vehicle moving directly at the side and ahead
Technical implementation
To do this the radar sensors control unit receives or transmits the following information or requests:
Input factors:
- Object recognition
- Driver request over the combination switch
- Vehicle speed/acceleration
- Acceleration/yaw rate
- Engine drive torque
- Accelerator pedal position
Initial parameters:
- Increase/reduce engine torque
- Increase/reduce the braking torque
- Engage targeted gear
- Emit warning tones, system or warning messages
Convoy driving
The convoy driving function is only available in selected Western European countries with corresponding legislation (overtaking on the right prohibited at speeds in excess of v = 80 km/h, as well as an overtaking speed limit relative to the convoy of max. v = 20 km/h). If a convoy forms in the left-hand lane due to the current traffic situation that could theoretically be overtaken in the right-hand lane, this is detected by DISTRONIC PLUS. A convoy overtaking maneuver in the right-hand lane (relative overtaking speed to convoy ≤ 20 km/h, maximum overtaking speed v = 85 km/h) is only initiated if the following requirements have been met:
- Speed of convoy ≤ 80 km/h
- Well built, multiple-lane road with a permissible maximum speed of v ≥ 80 km/h
Technical implementation
To do this the radar sensors control unit receives or transmits the following information or requests:
Input factors:
- Object recognition
- Vehicle speed
- Accelerator pedal position
- Engine drive torque
- GPS signals/signals for traffic assessment
Initial parameters:
- Increase/reduce engine torque
- Increase/reduce the braking torque
- Engage targeted gear
- Emit warning tones, system or warning messages
Additional function requirements for steering interventions by the steer assistant
- No trailer operation recognized (with code 550 (Trailer hitch))
- Tire pressure of all wheels within the tolerance range (run-flat mode not active) (with CODE 475 (Tire pressure monitor) or CODE 477 (Tire pressure loss warning))
- Standstill comparison successfully completed
- Lane width s > 2.6 m
Interventions in the steering by the Steer Assist
The Steer Assist supports the driver in maintaining directional stability (lateral guidance). By means of targeted steering intervention it keeps the vehicle on course and prevents it from unintentionally deviating from the road. If e.g. no lane markings are detected in urban traffic or in a highway traffic jam because of the proximity to the vehicle in front, the stereo multifunction camera evaluates object-related data of the preceding vehicle.
If the electrical power steering control unit recognizes no torque or an insufficient torque on the steering wheel ("Hands-Off-Detection") for t > 10 s, it transmits appropriate information to the radar sensors control unit via the suspension FlexRay. The radar sensors control unit transmits a message via the chassis FlexRay, electronic ignition lock control unit and user interface CAN to the IC. The message is displayed in the IC (icon gray with red hands).
If the driver does not react to the message within t = 5 s, an additional acoustic message is output via the instrument cluster speaker. The radar sensors control unit transmits the request to output a warning tone via the suspension FlexRay, electronic ignition lock control unit and user interface CAN to the IC. The IC directly actuates the speaker IC, and the volume of active audio sources is reduced simultaneously. In this case the radar sensors control unit renders the Steer Assist passive. "Hands-Off Detection" is suppressed by the radar sensors control unit at a vehicle speed of v < 10 km/h (intelligent "Hands-Off Detection"). The status of the Steer Assist is continuously shown to the driver on the multifunction display of the instrument cluster. A message (optical and acoustic) is also always issued if there is a concrete danger situation recognized.
Display on the instrument cluster
The output of the icons for the system status and for steering readiness takes place in the lower area of the IC. The icon "Hands-Off-Detection" is shown in the middle in the IC.
The interventions in the steering of the Steer Assist is reduced as the speed increases, when the vehicle is driven on narrow streets or with a limited field of view of the stereo multifunction camera.
Detailed information about the electric power steering is available in a separate document.
The following traffic situations lead to object guidance being aborted or Steer Assist being rendered passive:
- If the vehicle in front changes lane, the radar sensors control unit stops object-related lateral vehicle guidance and switches to lane-related guidance, provided that a lane has been detected.
Otherwise the vehicle in front is followed.
- If there is another vehicle in the blind spot when the vehicle in front changes lane, the Steer Assist is rendered passive and object-related lateral vehicle guidance is aborted in order to avoid a collision.
- If a vehicle is being followed that narrowly misses a parked vehicle, for example, object-related vehicle guidance is aborted and the Steer Assist is rendered passive in order to avoid a collision with the parked vehicle.
Automatic speed control
If the vehicle is in active distance control and the preceding vehicle accelerates to over v = 200 km/h or leaves the radar sensor system detection range, automatic distance control switches to automatic speed control.
Detailed information about the automatic speed control is available in a separate document.
Technical implementation
To do this the radar sensors control unit receives or transmits the following information or requests:
Input factors:
- Object recognition
- Driver request via the cruise control lever
- Vehicle speed/acceleration
- Acceleration/yaw rate
- Engine drive torque
- Accelerator pedal position
- Brake pedal position
Initial parameters:
- Increase/reduce engine torque
- Engage targeted gear
- Increase/reduce the braking torque
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 swinging-in vehicle lies below the value that was preselected, DISTRONIC PLUS decelerates the vehicle. If the requested braking power is not sufficient, an optical warning and warning tones are output and the driver must press the brake pedal. If the driver does not respond, the PRE-SAFE® brake initially initiates (in addition to optical warnings and warning tones) an automated partial braking and if necessary a maximum full-stop braking.
The negative acceleration (deceleration) is restricted to 50 % (ca. a = 5, 0 m/s2
) of the maximum brake power.
DISTRONIC PLUS is thereby deactivated. The driver is notified of this by the sounding of an intermittent tone over the instrument cluster speaker and a warning indicator in the instrument cluster's multifunction display. The driver can subsequently reactivate the DISTRONIC PLUS.
Technical implementation
To do this the radar sensors control unit receives or transmits the following information or requests:
Input factors:
- Object recognition
- Vehicle speed
- Brake pedal position
Initial parameters:
- Increase/reduce engine torque
- Increase/reduce the braking torque
- Engage targeted gear
- Emit warning tones, system or warning messages
Passing over roundabouts, T intersections and freeway exit lane
Before entering roundabouts, T intersections and freeway exits, the DISTRONIC PLUS brakes the vehicle.
If the vehicle driving immediately ahead leaves the detection area of the radar sensor system in one of the above-mentioned traffic situations, then the current speed is maintained:
- About. t = 10 s before a roundabout or a T intersection
- About t = 12 s before a freeway exit lane and about t = 4 s after a freeway exit lane
If, after this, no new vehicle is detected driving immediately ahead, the vehicle accelerates or decelerates to the established set speed and the DISTRONIC PLUS functions like the CC.
Information about the CC is contained in a separate document.
Since traffic situations are subject to alteration, the digital map data has to be regularly updated.
Technical implementation
To do this the radar sensors control unit receives or transmits the following information or requests:
Input factors:
- GPS signals/signals for traffic assessment
- Vehicle speed
- Brake pedal position
Initial parameters:
- Increase/reduce engine torque
- Increase/reduce the braking torque
- Engage targeted gear
Automated Stop Vehicle
For an active DISTRONIC PLUS the vehicle will follow the vehicle driving immediately ahead to standstill. In this case, deceleration is carried out through recuperation (models 222.004/057/104/157/163) or through 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).
Securing the vehicle using the DISTRONIC PLUS function (standstill control) does not replace securing the vehicle for parking.
Technical implementation
To do this the radar sensors control unit receives or transmits the following information or requests:
Input factors:
- Object recognition
- Vehicle speed
- Brake pedal position
Initial parameters:
- Increase/reduce engine torque
- Engage targeted gear
- Increase/reduce the braking torque
The following traffic situations show the limits of DISTRONIC PLUS:
Obstacles and stationary vehicles
The DISTRONIC PLUS 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.
Curves, curved entrances and exits
The DISTRONIC PLUS can only provides limited detection of vehicles in curves. One's own vehicle can then brake unexpectedly or late.
Vehicles moving across in front of one's own vehicle
DISTRONIC PLUS 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).
Lane change by other vehicles
The DISTRONIC PLUS does not yet detect the vehicle moving into the lane. The distance to the vehicle moving into the lane becomes too small.
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.
| Electrical function schematic for DISTRONIC PLUS with Steer Assist and Stop & Go Pilot | PE30.30-P-2066-97SEA | ||
| Overview of system components for driver assistance systems | GF54.00-P-9998LF |