Part 1
GF30.30-P-0006CA DISTRONIC PLUS Incl. BAS PLUS And PRE-SAFE Brake, Function
MODEL 207 with CODE (233) Distronic Plus
Function requirements, general
- No undervoltage or overvoltage
- Engine running or drivetrain operational
- "ADTR_AVL" (Advanced DISTRONIC PLUS) programmed in front SAM control unit with fuse and relay module (N10/1)
- Radar sensor system not switched off (manual or automatic)
- Long range radar soiling and function test completed successfully
- Electronic Stability Program (ESP(R)) not switched to passive mode
- Active ESP� intervention not recognized
- Vehicle is not in backward movement
- Gear range "D" engaged
- Parking brake not operated
The CDI control unit (N3/9) (for a diesel engine) or the ME-SFI control unit (N3/10) (for a gasoline engine) transmits the transmits the signal "Engine running" "Drivetrain operational" via the chassis CAN (CAN E).
The ESP(R) status is transmitted by the Electronic Stability Program Premium control unit (N30/7) via the chassis CAN.
The gear range status is sent by the EGS control unit (N15/3) (for transmission 722.6) or the fully integrated transmission control unit (Y3/8n4) (for transmission 722.9) via the drive train CAN (CAN C), CDI control unit or the ME-SFI [ME] control unit and chassis CAN. The status of the parking brake is detected by the parking brake indicator switch (S12). The front SAM control unit reads in the status of the parking brake indicator switch directly and transmits this via the chassis CAN.
Apart from the listed function requirements there is constant checking on safety grounds whether the driver is present in the vehicle.
Driver recognition takes place by the standstill coordinator which is implemented in the electronic stability program control unit.
The following vehicle components are monitored to do this:
- Driver door and driver belt lock (closed)
- Front passenger door (closed)
- Rear doors (closed)
- Engine hood (closed)
The detailed function of the standstill coordinator should be taken from the separate description "Adaptive Brake (ABR)".
DISTRONIC PLUS incl. BAS PLUS and PRE-SAFE brake, general points
Speed data:
The units and values given for the speed should be assigned to the possible national versions. Data in "miles per hour (mph)" refers to vehicles with code (494) USA version.
The DISTRONIC PLUS function automatically regulates the speed and the distance to the vehicle driving immediately ahead in a vehicle speed range from v = 0 to 200 km/h and from v = 200 to 0 km/h (v = 0 to 120 mph and from v = 120 to 0 mph) according to the request made by the driver.
There is furthermore a distance warning function included which advises the driver about a small distance to the vehicle driving immediately ahead. A warning is given about possible collisions with vehicles or stationary obstacles on one's own lane both optically and acoustically.
If the driver reacts to the collision critical warning with an emergency braking maneuver, the BAS PLUS function supports him in that. The required brake servo assistance is calculated according to the situation.
This means that the brakes remain applied automatically and as 2 intensively as required (max. approx. a = 10 m/s2). In this way it is possible to prevent a threatened collision or at least to reduce the severity of the accident.
If the driver does not react to the warning, the PRE-SAFE function decelerates the vehicle by automatically actuating the brakes to prevent a possible collision or to reduce the possible consequences. For this purpose, the PRE-SAFE brake permanently determines the potential danger of a head-to-tail crash occurring and initiates appropriate measures in accident critical situations to mitigate the effects of a collision.
The PRE-SAFE brake function supports the safety concept PRE-SAFE.
The PRE-SAFE brake function is described in detail in the separate function description "PRE-SAFE function".
The functions listed are controlled by the following control unit:
- Radar sensors control unit (N62/1) (up to 31.5.11)
- Video and radar sensor system control unit (N62/2) (as of 1.6.11)
The radar sensors control unit or the video and radar sensor system control unit intervenes to actively realize the functions in the engine timing as well as in the brake system.
The optical and acoustic warnings are emitted via the IC (A1).
Further partial functions of the DISTRONIC PLUS function are described in the separate function description "CC (TPM) function":
- Cruise control
- Variable SPEEDTRONIC (without code (494) USA version)
- Permanent limiter
Operation of the DISTRONIC PLUS function takes place via the CC lever (S40/4).
Design of the CC lever
S40/4 Cruise control lever
S40/4r1 DISTRONIC control
S40/4s1 Resume from memory switch
S40/4s2 Decelerate and set switch
S40/4s3 Accelerate and set switch
S40/4s4 OFF switch
S40/4s6 SPEEDTRONIC switch (with code (494) USA version)
S40/4v1 SPEEDTRONIC LED (without code (494) USA version)
Operation via the CC lever, Vehicles without code (494) USA version
5a Accelerate and set in 1 km/h increments
5b Accelerate and set in 10 km/h increments
6a Decelerate and set in 1 km/h increments
6b Decelerate and set in 10 km/h increments
7 Switching off of the DISTRONIC PLUS (acknowledgment for automatic driving off) or Variable SPEEDTRONIC (if no target speed is stored, the current speed is set as the target speed)
8 Increasing the specified distance for the DISTRONIC PLUS
9 Reducing the specified distance for the DISTRONIC PLUS
10 Selection option between DISTRONIC PLUS and variable SPEEDTRONIC
11 SPEEDTRONIC LED (lights up in the position variable SPEEDTRONIC)
12 Switching off the DISTRONIC PLUS or variable SPEEDTRONIC
Operation via the CC lever, Vehicles with code (494) USA version
13a Accelerate and set in 1 mph/h increments
13b Accelerate and set in 5 mph/h increments
14a Decelerate and set in 1 mph/h increments
14b Decelerate and set in 5 mph/h increments
15 Switching on of the DISTRONIC PLUS (acknowledgment for automatic driving off) or switching on of CC (if no target speed is stored, the current speed is set as the target speed))
16 Increasing the specified distance for the DISTRONIC PLUS
17 Reducing the specified distance for the DISTRONIC PLUS
18 Switching off of DISTRONIC PLUS
Detection range of the radar sensor system
1 System vehicle equipped with DISTRONIC PLUS including BAS PLUS and PRE-SAFE brake
2 The target vehicle (target object) moving directly ahead is detected by the long range radar sensors
3 The vehicle immediately ahead in the traffic is detected by the medium detection range of the long range radar sensors
4 The stationary vehicle on the driving lane edge and is detected by the short range radar sensors (detection of stationary objects is not possible in countries with approval for the 24-GHz radar system)
A Long range radar (up to s = 200 m, for a detection angle of about ( = 18°))
B Medium detection area of the radar sensor system (up to s = 60 m, for a detection angle of about ( = 60°))
C Short range radar (up to s = 30 m, for a detection angle of about ( = 80°))
The DISTRONIC PLUS function requires the following input factors to implement the functions distance control and distance warning:
- Object recognition in the short range
- Object recognition in the long range
Object recognition in the short range by means of the short range radar sensors (24 GHz short range radar):
The short range radar sensor system is not required in countries in which no approval exists for the 24-GHz radar system.
The short range radar sensors work in the 24 GHz frequency range for a maximum range of s = 30 m and is integrated in the following components:
- Left front bumper DISTRONIC (DTR) sensor (B29/2)
- Right front bumper DISTRONIC (DTR) sensor (B29/3)
The recording angle of the short range radar sensors is a maximum of Angular = 130°. Within a detection angle of Angular = 60° the angle is determined precisely and object s are still detected up to an angle of Angular = 130°.
The radar sensors communicate via the sensor-CAN (CAN S) with the radar sensors control unit or the video and radar sensor system control unit.
Due to legal requirements on the 24 GHz radar system (short range radar), the short range radar sensor system is automatically switched off in certain protected areas around radio astronomy stations.
The protected areas of the radio astronomy stations are stored in the form of Global Positioning System (GPS) coordinates in the radar sensors control unit or in the video and radar sensor system control unit.
The radio navigation system with Auto-Pilot-System (A2/56) (for code (511) Audio 50 APS incl. DVD changer or code (525) Radio MB Audio 50 APS) or the COMAND controller unit (A40/3) (for code (512) COMAND APS incl. DVD changer or code (527) COMAND APS with a single DVD drive (with navigation)) permanently transmits the current GPS coordinates via the interior CAN (CAN B), front SAM control unit and chassis CAN to the radar sensors control unit or the video and radar sensor system control unit, which reacts by switching off the short range radar sensors.
When the DISTRONIC PLUS function is active, the message "Radar sensor system automatically switched off, see operator's manual" is shown on the multifunction display (A1p13) of the instrument cluster.
When the vehicle leaves the protected area, the short range radar sensor system is switched on again automatically.
For an activated DISTRONIC PLUS function the message "DISTRONIC PLUS available again " is issued.
The driver has the option to switch the short range radar sensor system off and on manually over the "Vehicle settings" menu in the IC. If one seeks to manually switch on the short range radar sensors within a protected area, the message "Radar sensor system switched off automatically" is displayed in the multifunction display.
Schematic display of automatic radar sensor system shutoff
A1p13 Multifunction display
A2/56 Radio with auto pilot system (with code (511) Audio 50 APS with DVD changer or code (525) MB Audio 50 APS radio)
A28/11 Multifunction antenna
A40/3 COMAND controller unit (with code (512) COMAND APS incl. DVD changer or code (527) COMAND APS with single DVD drive (with navigation))
B29/2 DISTRONIC sensor (DTR) / left front bumper
B29/3 DISTRONIC sensor (DTR) / right front bumper
N62/1 Radar sensors control unit (up to 31.5.10)
N62/2 Video and radar sensor system control unit (as of 1.6.10)
GPS Global Positioning System
RAS Radio astronomy station
SB Restricted area for a radio astronomy station
Object recognition in the long range by means of the long range radar sensors (77 GHz long range radar):
The long range radar operates in the 77 GHz frequency range and is integrated into the DISTRONIC electric controller unit (A89).
The traffic area in the range s = 60 to 200 m in front of the vehicle is detected for a detection angle of Angular = 18°.
The traffic area in the range s = 0 to 60 m in front of the vehicle is detected for a detection angle of Angular = 60°.
The DISTRONIC control unit performs a soiling and function test to secure its perfect functioning after each engine start.
The function test requires an object in the detection range of the long range radar which is used as a reference value for the function test by the DISTRONIC control unit. The DISTRONIC PLUS cannot be activated if a malfunction is established or if there are no objects (for the function test) in the detection range of the long range radar. The DISTRONIC controller unit communicate via the vehicle dynamics CAN (CAN H) with the radar sensors control unit or the video and radar sensor system control unit.
The long range radar operates according to the pulse-duplicator principle which allows the distances and speeds of individual objects (e.g. vehicles) to be measured independently of each other.
Apart from information from the radar sensor system, the following additional information is needed in order to realize the automatic distance regulating system:
- Intensity of the acceleration in the longitudinal direction
- Direction of travel
- Vehicle speed
- Steering angle
Intensity of the acceleration in the longitudinal direction The requested maximum positive acceleration of the automatic distance control is limited on safety and comfort grounds to about a = 2.5 m/s2 while the negative acceleration is limited to about 40% (ca. g = 4 m/s2) of the maximum possible brake power.
The maximum positive acceleration requested for automatic distance control is antiproportional to the vehicle speed which means that limitation of the positive and negative acceleration reduces with increasing speed.
The positive and negative acceleration of the vehicle is detected by the yaw rate sensor for lateral and longitudinal acceleration (B24/15) and transmitted via the vehicle dynamics CAN.
Direction of travel and vehicle speed:
In order to determine the direction of travel and speed of the vehicle, the Electronic Stability Program Premium control unit directly reads in signals from the following components:
- Left front axle rpm sensor (L6/1)
- Right front axle rpm sensor (L6/2)
- Left rear axle rpm sensor (L6/3)
- Right rear axle rpm sensor (L6/4)
The wheel rotation direction is determined dependent on the drive variants. Information about this can be obtained in the separate description "Electronic Stability Program (ESP) function".
The Electronic Stability Program control unit transmits the information about the wheel speed and the wheel rotation direction via the chassis CAN to the radar sensors control unit or the video and radar sensor system control unit. The radar sensors control unit or the video and radar sensor system control unit computes the vehicle speed and defines the direction of travel based on this information.
Rotation angle:
The current rotation angle is detected by the steering wheel angle sensor (N49) whose signals are directly read in by the steering column tube module control unit (N80). The steering column tube module control unit transmits the data from the steering angle sensor via the chassis CAN to the radar sensors control unit or the video and radar sensor system control unit.