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Variable Speed Limiter, Function




Variable Speed Limiter, Function





Vehicle speed signal
ECU transmits the speed signal through the CAN data bus.

Vehicles with EZS control unit without column sleeve module (MRM)
The signals from the variable cruise control's switch unit are detected by the control unit EIS and transmitted over the CAN data bus.

Vehicles without EZS control unit
The signals from the variable cruise control's switch unit are transmitted directly to the engine-management ECU.

Vehicles with column sleeve module (MRM)
The signals from the pushbutton switch on the cruise control variable are detected by the steering column module and transmitted over the CAN data bus.

Function
Supplementary functions of the variable cruise control include:
- variable speed-governor function (VGB) extending from 30 km/h (20 mph) to the top speed of the vehicle
- Permanent speed limiter from 190 km/h (120 mph) to the top speed of the vehicle Excepting Model Series 168 and vehicles equipped with the multifunction steering wheel
- The accelerator pedal must be actuated further
- When the brakes are applied, the variable cruise control is not deactivated

1. Variable speed governor (VGB)
A slider on the variable cruise control witch unit is used to enable the variable speed-governor mode (LED in the button lights up). The speed at which the governor becomes active is set at the variable cruise control's switch unit.

If the engine's braking effect should prove insufficient to prevent the vehicle from accelerating beyond the preset speed during steep descents, an acoustic warning sounds to alert the driver that the brakes should be applied. When the ignition is switched OFF the preset speed data remain stored in the variable cruise control system.
Vehicles with Distronic (DTR) are braked.

1.1. Activation with vehicle stationary
- Engine ON
- Selector lever in P
- Actuation of the sliding part of the cruise control pushbutton switch so that the LED lights up.

To use SET ACCELERATION:
The display shows the lowest speed available for programming, 30 km/h or 20 mph. The switch button can then be tapped briefly or held down to raise the maximum speed in increments of 10 kph.

To use SET DECELERATION:
The display shows 30 km/h (20 mph).

To use SET MEMORY:
Activates last stored maximum speed, then raises this speed in increments of 1 kph.

Position OFF:
Shut off

1.2. Activation while driving
Actuation of the sliding part of the pushbutton switch for the cruise control so that the LED lights up
To use SET ACCELERATION:
The maximum speed jumps to the next round number, i.e., from 83 kph to 90 kph. The switch button can then be tapped briefly or held down to raise the maximum speed in increments of 10 kph.

To use SET DECELERATION:
The maximum speed falls to the next lowest round number, i.e., from 83 kph to 80 kph. Pressure can be maintained on the switch to lower the governed maximum speed in 10 kph increments by as much as 30 kph below instantaneous vehicle speed. The tip function must be used for adjustments beyond this point.

Caution! Vehicle speed drops.

To use SET MEMORY:
The last governed maximum speed is reactivated. If the current roadspeed is more than 30 kph abopve the currently stored maximum speed stored in the system, it will not be possible to activate the variable cruise control (the display flashes for approximately 5 s when the button is released). The reason that the cruise control remains inactive under these conditions is that substantial braking would be needed to achieve congervence with the stored speed. It is possible to increase the vehicle speed in stages each of 1 km/h.

1.3. The speed limit is deactivated when:
- The cruise control switch is moved to the position OFF
- for kick-down with the accelerator pedal
- Moving the sliding switch of the cruise control switch into cruise control position (LED off)

Cruise control deactivation via KICKDOWN:
Of the difference between the speed limit and the current speed is less than 20 km/hour the kick-down is recognised in this range then the variable speed limiter will be switched off (Example. 1).

E.g. 1: VGB = 100 kph, Current speed = 83 kph,
Kickdown, VGB cruise control cancels.
E.g. 2: VGB = 100 kph, current speed = 30 km/h,
kickdown up to 80 km/hour, VSL remains in operation.

Note: The sales designation for the cruise control systems with variable speed control is Speedtronic. Vehicles with a mechanical transmission and variable speed control are fitted with kick-down recognition.

2. Programmable permanent governed maximum speed except Model Series 168 and vehicles with multifunction steering wheel
The permanent maximum speed governor is available only for speeds between 190 kph and the maximum velocity of the vehicle. The entered figure represents the new "top speed" of the vehicle. The maximum speed programmed using this function is always valid, even when the variable cruise control is off and the cruise control is on.
As the vehicle approaches the programmed top speed, the display starts to flash the programmed figure; the governor function limits the speed. When a permanent top speed has been programmed, the figure flashes briefly in the display when the ignition key is switched on. If the system is set to the vehicle's top speed, no display appears.

To set or change the permanently governed top speed:
- Selector lever in P
- Motor AUS
- Ignition ON
- Actuation of the sliding part of the pushbutton switch for the cruise control so that the LED lights up.
- Pull cruise control switch to STORE position
- Use SET DECELERATION or SET ACCELERATION to change the speed in 5 kph increments.
- Pull cruise control switch into STORE possition and hold it in place until the warning buzzer sounds.
- The new top speed is entered and stored in the system.

To delete the permanent governed top speed:
- Selector lever in P
- Motor AUS
- Ignition ON
- Actuation of the sliding part of the pushbutton switch for the cruise control so that the LED lights up.
- Pull cruise control pushbutton switch to STORE position
- The current figure for the permanent speed limit is displayed (flashes)
- Actuate SET ACCELERATION to increase the value of the speed limit above the maximum speed of the vehicle (Display: "---km/hour")
- Pull cruise control pushbutton switch to STORE position
- The warning buzzer sounds
- Permanent speed limit is erased.

Note: For vehicles with a multi-functional steering wheel and multi-functional display the permanent speed limit is replaced by the winter tire limit in the instrument cluster.
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