DISTRONIC PLUS with Steer Assist and stop & go pilot function - GF30.30-P-0017RF
Model 205, 253 with code 266 (DISTRONIC PLUS with Steer Assist and Stop & Go Pilot)
Function requirements, general
- No undervoltage or overvoltage
- "ADTR_AVL" (Advanced DISTRONIC PLUS) programmed in electronic ignition lock control unit
- "ALS_AVL" (Advanced Lateral Support) 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 recording (e.g. vehicle 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, and 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 sensors control unit.
- Soiling and function test for the stereo MFK
- Electronic Stability Program (ESP®) not switched to passive mode
- No active ESP® intervention recognized (vehicle not in sliding movement)
- Standstill coordinator, enable issued (driver door/driver belt buckle and front passenger door closed)
- DISTRONIC PLUS switched on via the CRUISE CONTROL lever
- Steer Assist switched on using the Steer Assist button
DISTRONIC PLUS with steering assistant function, general
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 again allows this, the DISTRONIC PLUS accelerates the vehicle automatically up to the set target speed and therefore frees up the driver from these tiring routine tasks (e.g. frequent starting off and braking in stop-and-go or convoy driving traffic).
If the DISTRONIC PLUS recognizes that strong braking is necessary (e.g. weaving in traffic, a stationary obstacle), the DISTRONIC warning lamp in the instrument cluster comes on 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 acoustic warning and brakes, he will be assisted in this 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 fails to respond to the acoustic warning, the PRE-SAFE® brake initiates (in addition to the visual and acoustic warnings) an automated partial and then emergency 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. Here, the Steer Assist in a vehicle speed range of v = 60 to 130 km/h is oriented towards the lane marking or vehicles in front (only if lane markings are not available), in a vehicle speed range of v = 130 to 200 km/h only on lane markings and at a vehicle speed range of v = 0 to 60 km/h on vehicles in front taking into account the lane markings, e.g. during 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 Steer Assist is designed to be so sensitive that it recognizes whether the driver has his hands on the steering wheel. The Steer Assist will warn about this if this is not the case. The Steer Assist is implemented in the radar sensors control unit. The course of the road in front of the vehicle and the vehicles ahead are recorded via the stereo multifunction camera and the radar sensor system. The steering movements that are requested are carried out by the electric steering.
The following subfunctions of the DISTRONIC PLUS are described in the separate subfunction "Cruise control function":
- 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.
Design of the cruise control lever
For every operation of the CC lever the distance to the vehicle immediately ahead is displayed for t = 5 s in the multifunction display of the IC. 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 driving immediately ahead can be set via the DISTRONIC control in seven stages between about. t = 1.0 and 2.0 s.
The radar sensors control unit also evaluates the following input factors:
- Signal "Engine running" or "Drivetrain operational" (function requirements)
- Status of parking brake (function requirements)
- Engaged gear range (function requirements)/transmission mode
- 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
- Braking 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 Electronic Stability Program control unit transmits the status of the parking brake to the radar sensors control unit via chassis FlexRay. 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 from the wheel speed. 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 wheel speed signals 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 (Steer Assist only):
The Steer Assist can be switched on and 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 the Steer Assist is displayed to the driver by activation or deactivation of the LED in the Steer Assist button, among other things. 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" appears for t = 5 s on the instrument cluster multifunction display. 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 impulse 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 area in front of the vehicle up to a distance of s = 200 m within 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 radar concept, which enables the distances and speeds of individual objects (e.g. vehicles) to be measured independently of each other.
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:
- Vehicle in front within recording range of s 1 to 40 m (speed-dependent)
- Width of vehicle traveling ahead s 1.30 to 3.20 m
- Center line offset of vehicle to vehicle in front: s 35 cm (when control starts)
- Vehicle speed v > 0 to 60 km/h
- No lane change (turn signal not set)
Stereo multifunction camera object recording
The integrated control unit in the stereo multifunction camera 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 the image data 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
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 head unit evaluates the received GPS data using additional information for traffic assessment, and transmits appropriate information via the user interface CAN, the electronic ignition lock control unit and the chassis FlexRay to the radar sensors control unit.
Engine drive torque:
Information about the currently available engine torque is transmitted by the CDI control unit or the ME-SFI [ME] control unit via the drive train CAN, the powertrain control unit and the chassis FlexRay to the Electronic Stability Program control unit, which then evaluates this accordingly and transmits it via 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/yaw rate is detected by the acceleration sensor integrated into the Supplemental Restraint System control unit. The Supplemental Restraint System control unit transmits appropriate values via the vehicle dynamics CAN, the Electronic Stability Program control unit and the chassis FlexRay to the stereo multifunction camera (Steer Assist only) and the radar sensors control unit. For an active Steer Assistant and subsequent dangers in a traffic jam the stereo MFK calculates the exact position of the vehicle driving immediately ahead based on these values.
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 reads in the status of the transmission mode button directly, and sends it over the telematics CAN, head unit, user interface CAN, electronic ignition lock control unit, chassis 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 from the steering wheel angle sensor and transmits the information about the steering wheel angle via the suspension FlexRay to the radar sensors control unit.
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 transmits the status of the brake pedal via the chassis FlexRay to the radar sensors control unit.
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 chassis FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster which issues the corresponding system or warning messages on the multifunction display 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
- Steering interventions by the steer assistants
- 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:
- Call up the last selected target speed with resume from memory switch on CC lever (selected target speed v 30 km/h)
- Briefly operate accelerator pedal
The vehicle starts 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.
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
The automatic distance control can only be activated while driving (v < 30 km/h (mph)) if a vehicle driving immediately ahead was 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 according to the current vehicle status. To do this the Electronic Stability Program control unit assesses various variables such as the required braking torque.
Model 205.012/047/147/212/247
with code 266 (DISTRONIC PLUS with Steer Assist and Stop & Go Pilot)
The kinetic energy is converted within defined limits into electrical energy (regenerative braking). If the required braking torque exceeds the deceleration through regenerative braking (for example in the event of emergency braking), then the Electronic Stability Program control unit also 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.
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)
When overtaking above a speed of v = 70 km/h the vehicle is also automatically accelerated. 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 the appropriate 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 a 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 legally 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 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
Steering interventions by the steer assistants
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. For example, if no lane markings are detected in urban traffic or in a motorway traffic jam because of the proximity to the vehicle in front, the stereo multifunction camera evaluates object-related data of the vehicle in front.
If the electrical power steering control unit detects zero or insufficient torque at the steering wheel for t > 10 s ("Hands-Off Detection"), it sends corresponding information via the chassis FlexRay to the radar sensors control unit and a message via the chassis FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster. The message is displayed in the multifunction display (Icon gray with red hands).
If the driver does not react to the message within t = 5 s, an additional acoustic message is issued 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. The "Hands-Off Detection" is suppressed by the radar sensors control unit at vehicle speeds 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.
Status of the Steer Assist, representation in the IC
Showing of the icons for the system status and for steering readiness appears in the upper area of the multifunction display.
The function 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.
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 vehicle driving immediately ahead accelerates above v = 200 km/h or removes itself from the detection area of the radar sensor system, the automatic distance control switches over into automatic speed control.
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 moving in vehicle is below the value which was programmed, the DISTRONIC PLUS function brakes the vehicle. If the requested brake power is not sufficient, a visual and an acoustic warning is issued, and the driver has to press the brake pedal. If the driver fails to respond, PRE-SAFE® brake initiates (in addition to the visual and acoustic warnings) an automated partial and then emergency braking.
The negative acceleration (deceleration) is restricted to 50% (approx. 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 in the multifunction display of the instrument cluster. 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 the separate function description "CC function".
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. Deceleration here is through regenerative braking (for model 205.012/047/147/212/247) or 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 coordinator safety strategy).
- Object recognition
- Vehicle speed
- Brake pedal position
Initial parameters:
- Increase/reduce engine torque
- Engage targeted gear
- Increase/reduce the braking torque
Securing the vehicle using the DISTRONIC PLUS function (standstill coordinator) 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:
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 a stationary vehicle 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-2066-97FBA |
| Overview of system components for driver assistance systems | GF54.00-P-9998RF |