Part 2
63 02 03 007 Adaptive Headlight - Continued
Speed-dependent evaluation of signals
Depending on the driving speed, the adaptive headlights are controlled using the following signals: Signals from the steering angle sensor and signals from rotation-rate sensor (in the DSC sensor).
The encoding (at the end of line) determines the priority assigned to sensor signals above which speed threshold.
Adjustment of headlight horizontal aim
The stepper motor controllers move the headlights to the right or left when the vehicle corners.
Horizontal movement range of headlights:
- Inwards, i.e. towards centre of vehicle: up to max. 8°
- Outwards: up to max. 15°
Example: Right-hand bend: The right-hand headlight turns by up to 15° (the right-hand headlight is the "inside" headlight on a right-hand bend).
Viewed from the vehicle, the right-hand headlight moves "outwards".
The left-hand headlight moves up to 8° (the left-hand headlight moves towards the centre of the vehicle, i.e. "inwards" as viewed from the vehicle).
The headlight on the outside of the bend has to reach its end position at the same time as the headlight on the inside of the bend so that the carriageway remains smoothly and evenly illuminated.
On a right-hand bend, the left-hand headlight is on the outside of the bend. The right-hand headlight is on the inside of the bend.
Deactivation of adaptive headlights function under extreme driving conditions
If the vehicle drifts, skids and loses sideways grip, the adaptive headlights function is deactivated as follows:
- The headlights are returned to the straight-ahead position. The headlights are no longer turned.
- The low-beam headlights remain on.
Deactivation of adaptive headlights function in response to system faults
Until 09/2007, a system fault will be indicated by the indicator light on the light switch flashing.
From 09/2007 system fault will be indicated by a Check Control message in the instrument panel.
Dazzling of oncoming traffic must be prevented in the event of a system fault.
For this reason, the adaptive headlights function is deactivated as follows:
- If the stepper motors are still functional, the headlights are returned to the straight-ahead position. The headlights are no longer moved towards bends in the road.
- If it is no longer possible for a headlight to be moved back to the straight-ahead position, the headlight is lowered (by the stepper motors for automatic headlight beam throw adjustment). This prevents dazzling of oncoming traffic.
- Vehicles up to 09/2007: If the headlight cannot be lowered, the bi-xenon bulb in this headlight is disabled as follows:
When the vehicle is parked up, the control unit registers rest state for the adaptive headlights, as follows: Vehicle standstill and terminal R OFF for several minutes.
The next time the vehicle is restarted, the bi-xenon light of the defective headlight is not switched on.
The front fog lights are switched on in order to ensure a minimum level of lighting.
The low-beam headlights are not switched off while the vehicle is in motion.
NOTE: From 09/2007, the low-beam headlights will not be switched off in the event of a system fault.
If a system fault develops in the adaptive headlights, the low-beam headlights for the affected headlight will not be switched off.
Setting headlights to parked position
When terminal R is switched off, the headlights move to the parked position. The parked position is important for the headlights' next reference run: From the parked position, the headlights are run through a reference run in the pre-drive check. During each reference run-sequence, the control unit for adaptive headlights relearns the straight-ahead position for the headlights.
When the headlights have reached the parked position, the stepper motor controllers SMCs inform the control unit for adaptive headlights ("confirmation").
The control unit for adaptive headlights deactivates the stepper motor controllers.
The after-running period lasts approx. 10 seconds.
Automatic headlight beam throw adjustment
If the optional equipment "Adaptive headlights" is fitted, the control unit for adaptive headlights also controls the automatic headlight beam throw adjustment.
The automatic headlight beam throw adjustment adapts the headlight range for different vehicle inclinations. Variations in the vehicle inclination angle are produced by vehicle loads and braking or acceleration in extreme driving situations. The automatic headlight beam throw adjustment moves the headlights up and down as required.
The control unit for adaptive headlights also controls the automatic headlight beam throw adjustment as follows:
1. The ride height sensors and the brake light switch supply the signals for the automatic headlight beam throw adjustment.
2. The control unit for adaptive headlights computes the vehicle inclination (longitudinally to the roadway) from the signals.
3. The stepper motors for the automatic headlight beam throw adjustment automatically and dynamically control the headlight beam throw.
The headlight range is adjusted so that the actual headlight beam throw conforms to the legally required headlight beam throw as follows:
- If vehicle rear is lower than front: The actual headlight beam throw will be longer than the legally stipulated headlight beam throw. The headlight beam throw is lowered to reduce the headlight beam throw to match the legal requirement.
- If the vehicle is horizontal: The actual headlight beam throw will be the same as the legally stipulated headlight beam throw .
- If vehicle front is lower than rear: The actual headlight beam throw will be shorter than the legally stipulated headlight beam throw. The headlight beam throw is raised to increase the headlight beam throw to match the legal requirement.
Adaptive headlights for automatic driving lights control
The automatic driving lights control feature (optional equipment in conjunction with the rain/light sensor) automatically switches the side lights and low-beam headlights on or off.
Switch-on conditions:
- The automatic driving lights control must be encoded (in the light module on the E60, E61, E63, E64, E65, E66 , in the footwell module on the E70, E71, E72, E81, E82, E87, E88, E89, E90, E91, E92, E93).
- The light switch position must be A ( A for automatic driving lights control and adaptive headlights).
- The rain/light sensor must be installed and operational.
The rain/light sensor detects the ambient brightness.
The rain/light sensor transmits the following requests to the light module (on the E70, E71, E72, E81, E82, E87, E88, E89, E90, E91, E92, E93: footwell module):
- Ambient brightness low: In twilight, darkness, in an underground garage or tunnel.
"Switch on low-beam headlights" request
- Ambient brightness sufficient.
"Switch off low-beam headlights" request
If only the side lights are to be switched on, the light switch must be set to side lights (switch position 1).
When the light switch position is set to "A", the control unit for adaptive headlights is also activated:
- When the automatic driving lights control function switches on the low-beam headlights (e.g. at dawn/dusk), the adaptive headlights function is notified at the same time.
The control unit for adaptive headlights thus assumes control of the automatic headlight beam throw adjustment.
- The signals from the rain/light sensor are also evaluated (E60, E61, E63, E64, E65, E66: by the light module; E81, E82, E87, E88, E90, E91, E92, E93: by the footwell module).
The headlights are not turned when the vehicle is cornering until total darkness sets in.
The message "low-beam headlights on" is given individually for each headlight.
If a headlight fails, the adaptive headlights are switched off. The front fog lights are switched on in order to ensure a minimum level of lighting.
Turning lights
The cornering light is linked to the adaptive headlight (optional equipment 524).
The footwell module (FRM) uses the following signals to adjust the turning lights:
- Steering angle
- Yaw rate
- Status, reverse gear
> E81, E82, E88, E89, E92, E93 with the series launch and E87 from 03/2007
Instead of the high beam headlight (H7), the headlight with turning light has a fixed additional reflector with an H3 bulb. The special styling of the headlight lens prevents dazzle to the front.
The graphic shows the main headlight with turning light on the E81, E82, E87, E88, E89, E92, E93
1. Bi xenon lamp
2. H8 bulb for side lights and daytime driving lights
3. H3 bulb for turning lights
4. Reflector for cornering light
The graphic shows the headlight with turning light on the E81, E82, E87, E88, E89, E90, E91, E92, E93
1. Turning left
2. Turning right
The following prerequisites must be satisfied for the turning lights to be switched on:
- Terminal 15 ON
- Light switch in position "A"("A" stands for automatic driving lights control)
- Rain/light sensor identifies twilight or darkness (threshold value exceeded)
At driving speeds greater than 70 kph, the cornering light is no longer switched on.
> European version: For legal reasons, the turning lights on the European version can only be activated via the turn indicator at speeds up to 40 km/h.
When reversing, the footwell module (FRM) activates the turning lights as follows in the speed range 0 km/h to 35 km/h:
- US version, both sides
- Other countries, only outer side of bend
When the turn indicator is switched on: If the vehicle is stationary, the turning lights will automatically be deactivated after approx. 4 seconds, e.g. when waiting at traffic lights. However, the turning lights can be activated again with the turn signal/high beam switch (up to 3 times) until the reflector has reached a certain temperature. A temperature model protects the headlights against excessive thermal load.
The switching-off conditions for the turning light depend on the country concerned.
NOTE: Temperature monitoring by temperature model.
A temperature model in the footwell module calculates the temperature of the reflector. The temperature at the reflector must not exceed a certain value. If a critical temperature is reached, the footwell module (FRM) will deactivate the turning lights. After a cooling-down period, the cornering light can be switched on again.
> E70; E71, E72 with series launch
The turning lights are implemented with the front fog lights. (Reason: The installation position of the headlights is too high for the turning lights. This prevents legal specifications from being adhered to.)
Depending on activation, the right-hand and/or left-hand front fog light is switched on. The turning lights are activated by the light module (LM).
The front fog lights have an additional reflector to improve illumination of the areas to the sides.
When turning, the front fog light on the inside of the turn is automatically activated. The additional reflector for the turning light reflects the light beam towards the turning area.
The turning light is not switched on suddenly but rather dimmed in accordance with special time parameters. Depending on the country concerned, the turning light is switched on when cornering.
The graphic shows the front fog light on the E70The graphic shows the front fog light on the E70
1. Additional reflector for the turning light
2. Reflector for the front fog lights
3. Bulb
The following prerequisites must be satisfied for the turning lights to be switched on :
- Terminal 15 ON
- Light switch in position "A" ("A" stands for automatic driving lights control)
- Rain/light sensor identifies twilight or darkness (threshold value exceeded)
and
- Turn signal indicator ON (not one-touch flashing)
- Speed range (forwards travel):
- European and Japanese version from 0 km/h to 35 km/h
- US version from 0 km/h to 65 km/h
- Swivel angle (theoretical):
- when stationary ≥ 77°
- when driving ≥ to 10°
Alternatively
- Speed range (reversing):
- 0 km/h to 35 km/h
- Swivel angle (theoretical):
- when stationary or driving ≥ 70°
If the vehicle is stationary, the turning lights will automatically be deactivated after a certain time, e.g. when waiting at traffic lights. However, the turning lights can be switched on again using the turn signal/high beam switch
The following prerequisites must be satisfied for the turning lights to be switched off :
- Light switch not in position "A"("A" stands for automatic driving lights control)
- Rain/light sensor does not identify twilight or darkness (fallen below lower threshold value)
Alternatively
- Turn indicator OFF
- Speed range (forwards travel):
- European and Japanese versions ≥ 40 km/h
- US version ≥ 70 km/h
- Swivel angle (theoretical):
- when stationary 77°
- when driving 10°
Alternatively
- Speed range (reversing): ≥ 40 km/h
- Swivel angle (theoretical): when stationary and when driving below a certain value
Alternatively
- Vehicle skids and swings out.
Alternatively
- Front fog lights are switched on with the front fog lights switch.
Adaptive headlight beam throw adjustment
The adaptive headlight beam throw adjustment is employed when driving through dips and over crests. In accordance with a request from the control unit, the headlight driver module activates the swivel module via the stepper motors and in this way adjusts the headlight beam throw.
When the vehicle passes through a dip, the headlight beam throw is increased. The swivel module is moved up slightly. The roadway is illuminated a greater distance ahead.
When the vehicle passes over a crest, the headlight beam throw is reduced somewhat. The swivel module is moved down slightly. This reduces dazzling effect of an oncoming vehicle.
Variable light distribution (depending on the national-market version)
The variable light distribution enables a broader illumination of the roadway ahead of the vehicle. In accordance with a request from the control unit, the headlight driver module activates the swivel module via the stepper motors and in this way adjusts the light distribution. The transitions between the individual light distributions are smooth. In conjunction with the Adaptive Headlight optional equipment, the following variable light distribution are available:
- Engine start
In switch position "A"(light switch in the switch position for automatic driving lights control) and terminal 15 ON, both headlights execute a reference run. That means: Both swivel modules are moved down slightly and then to the desired position (visible when the vehicle is parked in front of a wall: The light cone moves down and then back up). The desired position depends on the load status of the vehicle.
When the engine is started, the headlight driver module initially controls the city light distribution.
- City light distribution
The city light distribution enables a broader illumination of the left roadway at low speeds. The link headlight is moved approx. 12° to the left and approx. 0.7° downwards. The city light distribution is activated from engine start to a driving speed of approx. 50 km/h.
- Country road light distribution
The country road light distribution is the same as the standard low-beam headlights. At a driving speed above approx. 50 km/h, the city light distribution is changed to the country road light distribution. Below a driving speed of approx. 50 km/h, the footwell module (FRM) changes the light distribution back to city. The country road light distribution represents the basic setting for the headlights. The basic setting is assumed when there are faults in the complete light distribution system.
- Motorway light distribution
The motorway light distribution increases the range of the driving light. The left headlight is moved approx. 3.5° to the left and approx. 0.25° downwards. The right headlight is moved approx. 0.2° upward. If the vehicle speed exceeds 110 km/h for longer than 30 seconds, or if 140 km/h is exceeded, the footwell module switches on the motorway light distribution. If the vehicle speed drops below 110 km/h, the headlights are gradually reset, depending on the driving speed. This takes places in stages (110 km/h - 100 km/h - 90 km/h - 80 km/h). The country road light distribution is activated again at 80 km/h and below.
- Fog light distribution
The fog light distribution is activated when the fog lights are switched on. The fog light distribution can be combined with the city light distribution and the country road light distribution. The link headlight is moved approx. 8° to the left and approx. 0.7° downwards. If the high beam headlights are switched on while the fog light distribution is active, the headlight moves to the basic setting, i.e. to the country road light distribution.
Switch-on conditions
The control unit for adaptive headlights is "awake" from terminal 15 ON. The movement of the lights is subject to the following preconditions:
- Reverse gear must not be engaged.
- The system is trouble-free (indicator light not flashing and no Check Control message)
- The bulbs for the bi-xenon lights are OK in both headlights.
- The vehicle must not be skidding or fishtailing.
- The rain/light sensor must identify darkness.
- Additional switch-on conditions: automatic driving lights control is active (light switch position "A", see above).
Notes for Service department
WARNING: Exercise caution when working on bi-xenon headlights
Whenever checking or working on the headlights, always observe the safety regulations and accident prevention regulations. The headlight system has dangerously high voltage.
- General information: [more ...]
- Diagnosis: [more ...]
- Encoding/programming: [more ...]
- Car & Key Memory:
> E60, E61, E63, E64, E65, E66
The sensitivity of the driving light sensor can be set to one of 2 stages with the Car & Key Memory.
> E70, E71, E72, E81, E82, E87, E88, E89, E90, E91, E92, E93
All Car & Key Memory functions are programmed inside the vehicle itself.
(Please refer to the Personal profile section of the Owner's Handbook: Personal profile for a maximum of 3 infrared remote control units via the display in the instrument panel or via the Central Information Display.)