GF30.30-P-0001CA Cruise Control (CC), Function
GF30.30-P-0001CA Cruise Control (CC), Function
- MODEL 207
Function requirements, general
- Circuit 61 ON or "PT_Rdy" (drivetrain ready) signal set
- Vehicle speed v ≥ 30 km/h up to 250 km/h (without code (494) USA version)
- Vehicle speed v ≥ 20 mph up to 150 mph (for code (494) USA version)
- Gear range "D" engaged
The circuit 61 status or the "PT_Rdy" signal is sent by the CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) via the chassis CAN (CAN E)
Cruise control - general
The CC function belongs to the driver assistance system and is integrated according to the model and installed equipment in the following control unit:
- Electronic Stability Program control unit (N30/4) (without code (233) DISTRONIC PLUS)
- Premium Electronic Stability Program control unit (N30/7) (with code (233) DISTRONIC PLUS)
- Radar sensors control unit (N62/1) (up to 31.5.11 for code (233) DISTRONIC PLUS)
- Video and radar sensor system control unit (N62/2) (as of 1.6.11 (for code (233) DISTRONIC PLUS)
The CC constantly controls the actual speed of the vehicle without operation of the accelerator pedal to the target speed set by the driver.
The vehicle is also automatically braked when driving down a hill to maintain the target speed through interventions in the service brakes. The function CC also includes the following functionalities:
- Variable SPEEDTRONIC (without code (494) USA version):
The variable SPEEDTRONIC function allows the driver to set an individual maximum speed for himself in the range v = 30 km/h up to the maximum vehicle speed of the vehicle.
- Permanent limiter:
The permanent limiter function allows the driver to permanently limit the maximum speed of the vehicle. This additional function is suitable for example for seasonal events such as operation of the vehicle with winter tires the speed rating of which is below the maximum possible speed of the vehicle.
The functionalities listed are regulated by means of a comparison between the specifications made by the driver and the actual value of the vehicle. The functions are identical for all vehicle models and packages. Differentiation takes place by the control unit which includes the CC function.
To do this the respective control unit determines and analyzes the following input factors:
- Vehicle speed
- Cruise control lever control signals (S40/4)
- Status of accelerator pedal
Vehicle speed:
The Electronic Stability Program control unit reads in signals from the following components directly for computation of the vehicle speed:
- 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)
For vehicles with code (233) DISTRONIC PLUS, the Electronic Stability Program control unit transmits the signals from rpm sensors via the chassis CAN to the radar sensors control unit (up to 31.5.11) or to the video and radar sensor system control unit (as of 1.6.11). The radar sensors control unit or the video and radar sensor system control unit then computes the vehicle speed itself.
Cruise control lever control signals:
The control signals from the following components are read in directly by the steering column module (N80):
- Resume from memory switch (S40/4s1)
- Decelerate and set switch (S40/4s2)
- Accelerate and set switch (S40/4s3)
- OFF switch (S40/4s4)
The steering column tube module control unit transmits the control signals via the chassis CAN according to model and installed equipment to the following control unit:
- Electronic Stability Program control unit (without code (233) DISTRONIC PLUS)
- Radar sensors control unit (up to 31.5.11 for code (233) DISTRONIC PLUS)
- Video and radar sensor system control unit (as of 1.6.11 (for code (233) DISTRONIC PLUS)
Status of accelerator pedal
The accelerator pedal sensor registers the status of the accelerator pedal (B37) whose signals are read in directly by the CDI control unit or the ME-SFI [ME] control unit.
The CDI control unit or the ME-SFI [ME] control unit transmits signals from the accelerator pedal sensor via the chassis CAN according to the model and installed equipment to the following control unit:
- Electronic Stability Program control unit (without code (233) DISTRONIC PLUS)
- Radar sensors control unit (up to 31.5.11 for code (233) DISTRONIC PLUS)
- Video and radar sensor system control unit (as of 1.6.11 (for code (233) DISTRONIC PLUS)
Operation:
The function cruise control and variable SPEEDTRONIC (without code (494) USA version) is operated over the cruise control lever. Selection of the speed takes place over the controls on the cruise control lever which are shown in graphic form below:
Design of the CC lever
S40/4 Cruise control lever
S40/4r1 DISTRONIC controller (with code (233) DISTRONIC PLUS)
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)
The units and values given for the speed in the following text should be assigned to the possible national versions. Data in "miles per hour (mph)" refers to vehicles with code (494) USA version.
The desired specified speed can be set in v = 1 km/h (1 mph-) or v = 10 km/h (5 mph) steps using the following controls:
- Resume from memory switch
- Decelerate and set switch
- Accelerate and set switch
Actuation of the switches listed up to the actuation point increases the set speed by v = 1 km/h (1 mph).
If the respective switch is actuated beyond the actuation point then the set speed increases each time by v = 10 km/h (5 mph). If the respective switch is held at or beyond the actuation point then the set speed increases automatically by an interval of t = 0.6 s.
The CC function includes the following subfunctions:
- Function sequence for automatic speed control
- Function sequence for SPEEDTRONIC
Additional automatic speed control function requirements
- Cruise control selected with SPEEDTRONIC switch (without code (494) USA version) (SPEEDTRONIC LED not illuminated)
- Electronic Stability Program (ESP(R)) not switched to passive mode
Function sequence for automatic speed control
The last stored specified speed is set by operation of the "Resume from memory" switch in as far as a specified speed was stored since the last engine start.
The specified speed is stored according to model and installed equipment by the following control unit:
- Electronic Stability Program control unit (without code ( 233) DISTRONIC PLUS)
- Radar sensors control unit (up to 31.5.11 for code (233) DISTRONIC PLUS)
- Video and radar sensor system control unit (as of 1.6.11 (for code (233) DISTRONIC PLUS)
If no target speed is stored, the current vehicle speed is set as the specified speed. The set specified speed is transmitted for display in the speedometer (A1p8) in the IC (A1) according to model and installed equipment to the IC by the following control unit:
- Electronic Stability Program control unit (without code (233) DISTRONIC PLUS)
- Radar sensors control unit (up to 31.5.11 for code (233) DISTRONIC PLUS)
- Video and radar sensor system control unit (as of 1.6.11 (for code (233) DISTRONIC PLUS)
View of the IC for an active automatic speed control
A Current speed
B Set specified speed
C Illuminated segments
If the automatic speed control is activated, the segments in the speedometer are illuminated from the specified speed to the end of the tachometer scale.
The following events lead to deactivation of the automatic speed control:
- Operation of the OFF switch
- Actuation of brake pedal
- Active regulation of the ESP(R)
- Speed v less than 25 km/h or v less than 17 mph
- Electric parking brake activated
- Gear range not "D"
Function on vehicles without code (233) DISTRONIC PLUS:
If the vehicle reaches the set specified speed, the engine power is reduced automatically.
To do this, the electronic stability program control unit sends the request to reduce the engine torque via the chassis CAN to the CDI control unit or the ME-SFI [ME] control unit. If the actual speed drops below the speed set by the driver, the torque is increased.
If the vehicle reaches the specified speed set by the driver in decel mode, for example by driving down a hill, then the Electronic Stability Program control unit actuates the service brake in a metered fashion over the traction system hydraulic unit (A7/3).
The A/T is further downshifted if necessary according to the operating condition to relieve the service brake system.
Downshifting of the A/T takes place autonomously by the A/T. This means that the Electronic Stability Program control unit just transmits information about the necessity of switching, which also includes limitation of the switching, via the chassis CAN to the CDI control unit or to the ME-SFI [ME] control unit.
The CDI control unit or the ME-SFI [ME] control unit passes on this information or request via the drive train CAN (CAN C) to the electronic transmission control control unit (N15/3) (transmission 722.6) or the fully integrated transmission control unit (Y3/8n4) (722.9) which implements this.
The driver also has the option, through actuation of the accelerator pedal via the accelerate beyond the set speed (e.g. when overtaking). After release of the accelerator pedal, the cruise control regulates to reach the set target speed again.
Function on vehicles with code (233) DISTRONIC PLUS:
If the vehicle reaches the set specified speed, the engine power is reduced automatically.
To do this the radar sensors control unit or the video and radar sensor system control unit transmits the request to reduce the engine torque via the chassis CAN to the Electronic Stability Program control unit which evaluates these as well as further requests.
The Electronic Stability Program control unit passes on these request, according to their relevance, via the chassis CAN to the CDI control unit or the ME-SFI [ME] control unit.
If the actual speed drops below the speed set by the driver, the torque is increased.
If the vehicle reaches the specified speed set by the driver in decel mode, for example by driving down a hill, then the Electronic Stability Program control unit actuates the service brake in a metered fashion over the traction system hydraulic unit. To do this the radar sensors control unit or the video and radar sensor system control unit transmits the corresponding request via the chassis CAN to the Electronic Stability Program control unit.
The A/T is further downshifted if necessary according to the operating condition to relieve the service brake system.
Downshifting of the A/T takes place autonomously by the A/T. This means that the radar sensors control unit or the video and radar sensor system control unit only transmits information about the necessity of switching which also includes limitation of the switching via the chassis CAN to the CDI control unit or the ME-SFI [ME] control unit.
The CDI control unit or the ME-SFI [ME] control unit passes on this information or request via the drive train CAN to the respective transmission control unit, which implements this.
The driver also has the option, through actuation of the accelerator pedal via the accelerate beyond the set speed (e.g. when overtaking).
After release of the accelerator pedal, the cruise control regulates to reach the set target speed again.
Function sequence for SPEEDTRONIC
The partial function SPEEDTRONIC encompasses the following subfunctions:
D Function sequence for variable SPEEDTRONIC (without code (494) USA version)
D Function sequence for permanent limiter
Additional function requirements for variable SPEEDTRONIC (without code (494) USA version)
- Variable SPEEDTRONIC selected with SPEEDTRONIC switch (SPEEDTRONIC LED illuminated)
- ESP(R) not switched passive
- No "Kick-down" recognized
Function sequence for variable SPEEDTRONIC (without code (494) USA version)
The function variable SPEEDTRONIC limits the maximum speed of the vehicle variably from a speed of v = 30 km/h. For example, if the driver sets the limit of the maximum speed to v = 50 km/h then the maximum speed of the vehicle is limited to v = 50 km/h.
Acceleration and braking of the vehicle is controlled by the driver.
If the cruise control lever is switched to the variable SPEEDTRONIC function, the cruise control function is deactivated.
The variable SPEEDTRONIC function is deactivated for:
- Operation of the OFF switch
- Kickdown (accelerator pedal pressed by greater than 90% and vehicle speed v less than 20 km/h below selected maximum speed)
Function on vehicles without code (233) DISTRONIC PLUS:
The Electronic Stability Program control unit compares, as for the case of the automatic speed control function, the current actual speed with the specified speed set by the driver.
The Electronic Stability Program control unit transmits the appropriate information via the chassis CAN to the CDI control unit or the ME-SFI [ME] control unit. Driving dynamics parameters are derived from these input factors for the engine timing while taking account of the requests from the driver.
If the driver accelerates the vehicle to the limit of the target speed, the Electronic Stability Program control unit sends a request via the chassis CAN to reduce the engine torque to the CDI control unit or the ME-SFI [ME] control unit.
If the vehicle reaches the specified speed set by the driver in decel mode, for example by driving down a hill, then the Electronic Stability Program control unit actuates the service brake in a metered fashion over the traction system hydraulic unit.
The A/T is further downshifted if necessary according to the operating condition to relieve the service brake system.
Downshifting of the A/T takes place autonomously by the A/T. This means that the Electronic Stability Program control unit just transmits information about the necessity of switching, which also includes limitation of the switching, via the chassis CAN to the CDI control unit or to the ME-SFI [ME] control unit.
The CDI control unit or the ME-SFI [ME] control unit passes on this information or request via the drive train CAN to the respective transmission control unit, which implements this.
Function on vehicles with code (233) DISTRONIC PLUS:
The radar sensors control unit or the video and radar sensor system control unit compares, as for the function automatic speed control, the actual speed with the specified speed set by the driver.
The radar sensors control unit or the video and radar sensor system control unit transmits the corresponding information via the chassis CAN to the Electronic Stability Program control unit.
The Electronic Stability Program control unit passes this on via the chassis CAN to the CDI control unit or the ME-SFI [ME] control unit. Driving dynamics parameters are derived from these input factors for the engine timing while taking account of the requests from the driver.
If the driver accelerates the vehicle up to the limit of the specified speed, the radar sensors control unit or the video and radar sensor system control unit transmits the request to reduce the engine torque to the Electronic Stability Program control unit which evaluates this and further requests.
The Electronic Stability Program control unit passes on these request, according to their relevance, via the chassis CAN to the CDI control unit or the ME-SFI [ME] control unit.
If the vehicle reaches the specified speed set by the driver in decel mode, for example by driving down a hill, then the Electronic Stability Program control unit actuates the service brake in a metered fashion over the traction system hydraulic unit. To do this the radar sensors control unit or the video and radar sensor system control unit transmits a corresponding request via the chassis CAN to the Electronic Stability Program control unit.
The A/T is further downshifted if necessary according to the operating condition to relieve the service brake system.
Downshifting of the A/T takes place autonomously by the A/T. This means that the radar sensors control unit or the video and radar sensor system control unit only transmits information about the necessity of switching which also includes limitation of the switching via the chassis CAN to the CDI control unit or the ME-SFI [ME] control unit.
The CDI control unit or the ME-SFI [ME] control unit passes on this information or request via the drive train CAN to the respective transmission control unit, which implements this.
Additional function requirements for permanent limiter
- Function of the permanent limiter is activated in the menu "Settings", the menu level "Vehicle" under "Limitation (winter tires)" in the IC.
The function of the permanent limiter can be activated independently of the status of the ESP(R).
Function sequence for permanent limiter
The maximum speed of the vehicle can be limited in v = 10 km/h or 5 mph steps of v = 160 to 240 km/h or v = 100 mph to 150 mph.
The IC transmits the set maximum speed via the chassis CAN, according to model and installed equipment, to the following control unit:
- Electronic Stability Program control unit (without code (233) DISTRONIC PLUS)
- Radar sensors control unit (up to 31.5.11 for code (233) DISTRONIC PLUS)
- Video and radar sensor system control unit (as of 1.6.11 (for code (233) DISTRONIC PLUS)
Function on vehicles without code (233) DISTRONIC PLUS:
If the vehicle reaches the maximum speed set by the driver the Electronic Stability Program control unit transmits the request to reduce the torque via chassis CAN to the CDI control unit or the MESFI [ME] control unit, which implements this.
If the vehicle reaches the maximum speed set by the driver in decel mode, for example by driving down a hill, then the Electronic Stability Program control unit actuates the service brake in a metered fashion over the traction system hydraulic unit.
The A/T is further downshifted if necessary according to the operating condition to relieve the service brake system.
Downshifting of the A/T takes place autonomously by the A/T. This means that the Electronic Stability Program control unit just transmits information about the necessity of switching, which also includes limitation of the switching, via the chassis CAN to the CDI control unit or to the ME-SFI [ME] control unit.
The CDI control unit or the ME-SFI [ME] control unit passes on this information or request via the drive train CAN to the respective transmission control unit, which implements this.
At about v = 10 km/h (v = 5 mph) below the set maximum speed a message is displayed in the instrument cluster multifunction display (A1p13) which indicates limitation of the maximum speed.
In the case of an active permanent limiter, the set speed cannot exceed the target speed set in the permanent limiter by the CC or variable SPEEDTRONIC (without code (494) USA version).
Function on vehicles with code (233) DISTRONIC PLUS: If the vehicle reaches the maximum speed set by the driver, the radar sensors control unit or the video and radar sensor system control unit transmits the request to reduce the engine torque to the Electronic Stability Program control unit which evaluates this and further requests. The Electronic Stability Program control unit passes on these request, according to their relevance, via the chassis CAN to the CDI control unit or the ME-SFI [ME] control unit, which implements this.
If the vehicle reaches the maximum speed set by the driver in decel mode, for example by driving down a hill, then the Electronic Stability Program control unit actuates the service brake in a metered fashion over the traction system hydraulic unit.
To do this the radar sensors control unit or the video and radar sensor system control unit transmits the corresponding request via the chassis CAN to the Electronic Stability Program control unit.
The A/T is additionally downshifted if necessary according to the operating condition to relieve the service brake system.
Downshifting of the A/T takes place autonomously by the A/T. This means that the radar sensors control unit or the video and radar sensor system control unit only transmits information about the necessity of switching which also includes limitation of the switching via the chassis CAN to the CDI control unit or the ME-SFI [ME] control unit.
The CDI control unit or the ME-SFI [ME] control unit passes on this information or request via the drive train CAN to the respective transmission control unit, which implements this.
At about v = 10 km/h (v = 5 mph) below the set maximum speed a message is displayed in the instrument cluster multifunction display which indicates limitation of the maximum speed.
In the case of an active permanent limiter, the speed set by the CC function or variable SPEEDTRONIC (without code (494) USA version) cannot exceed the specified speed set in the permanent limiter.
