System activation and automatic calibration

When terminal 15 is switched ON, the headlights always perform a calibration sequence, even if the dipped headlights are not switched on. The control unit for adaptive headlights sends the "perform calibration sequence" request to the stepper motor controllers (SMCs, control units for the headlight stepper motors). The stepper motor controllers actuate the stepper motors in the headlights. The calibration sequence is performed. In the calibration sequence, the headlights move as follows:

1. The headlights move to the right and left (= calibration sequence for adaptive headlights).
2. The headlights move up and down (= calibration sequence for automatic headlight-range adjustment).
3. At the end of the calibration sequence, the headlights are in the straight-ahead position.

Following the calibration sequence, the system is ready for operation.

When reverse gear is engaged, the headlights are moved to the straight-ahead position.

Activation of stepper motor controllers 

The control unit for adaptive headlights sends the stepper motor controllers (SMC) the nominal values for the positioner modules (position of positioner modules and speed of movement).

The control unit for adaptive headlights calculates the nominal values using the following signals:

• Vehicle road speed
• Steering angle (at speeds up to 50 km/h, dependent on encoding)
• Yaw rate (50 km/h upwards, see "Steering-angle sensor and DSC sensor" above)

Speed-dependent analysis of signals 

Depending on the road speed, the adaptive headlights are controlled using the following signals: Signals from the steering angle sensor and signals from yaw-rate sensor (in the DSC sensor).

The encoding (at the end of the production 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 range of movement of headlights:

• Inwards, i.e. towards center 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 middle 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 roadway 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 handling 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 dipped 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 lamp on the light switch flashing.

From 09/2007 system fault will be indicated by a Check-Control message in the instrument cluster.

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 tilted downwards (by the stepped motors for automatic headlight-range adjustment). This prevents dazzling of oncoming traffic.
• Vehicles up to 09/2007 

  If the headlight cannot be tilted downwards, the bi-xenon bulb in this headlight is disabled as follows:

  When the vehicle is parked up, the control unit registers sleep mode 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 foglights are switched on in order to ensure a minimum level of illumination.

  The dipped beam headlights are not switched off while the vehicle is in motion.

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 calibration sequence: From the parked position, the headlights are run through a calibration sequence in the pre-drive-check. During each calibration 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 ("verification").

The control unit for adaptive headlights deactivates the stepper motor controllers.

The run-down period lasts approx. 10 seconds.

Automatic headlight-range adjustment 

If the special equipment "Adaptive headlights" is fitted, the control unit for adaptive headlights also controls the automatic headlight-range adjustment.

The automatic headlight-range adjustment adapts the headlight range for different operating conditions. Variations in the vehicle tilt angle are produced by vehicle loads and braking or acceleration in extreme driving situations. The automatic headlight-range adjustment moves the headlights up and down as required.

The control unit for adaptive headlights also controls the automatic headlight-range adjustment as follows:

1. The ride-height sensors and the brake light switch supply the signals for the automatic headlight-range 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-range adjustment automatically and dynamically control the headlight range.

   The headlight range is adjusted so that the actual headlight range conforms to the legally required headlight range as follows:

   • If vehicle rear is lower than front:

     The actual headlight range will be longer than the legally stipulated range. The headlight beam height is lowered to reduce the headlight range to match the legal requirement.

   • If the vehicle is horizontal:

     The actual headlight range will be the same as the legally stipulated range.

   • If vehicle front is lower than rear:

     The actual headlight range will be shorter than the legally stipulated range. The headlight beam height is raised to increase the headlight range to match the legal requirement.

Adaptive headlights for automatic driving lights control 

The automatic driving lights control feature (option in conjunction with the rain-light sensor) automatically switches the side lights and dipped 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, E81, E87, E90, E91, E92, E93).
• The light switch must be in position "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 brightness of the ambient light.

  The rain-light sensor sends the following prompts to the light module (on the E70, E81, E87, E90, E91, E92, E93: footwell module):

  • Ambient brightness low: In twilight, darkness, in an underground garage or tunnel.

    "Switch on dipped headlights" request

  • Ambient brightness sufficient.

    "Switch off dipped 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 is set to position "A", the control unit for adaptive headlights is also activated:

• When the automatic driving lights control function switches on the dipped 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-range adjustment.

• In addition, signals from the rain-light sensor are evaluated (E60, E61, E63, E64, E65, E66: by the light module; 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 "dipped headlights on" is given individually for each headlight.

If a headlight fails, the adaptive headlights are switched off.

The front foglights are switched on in order to ensure a minimum level of illumination.

Turning lights 

The turning lights are coupled to the adaptive headlights (option 524).

The footwell module (FRM) uses the following signals to adjust the turning lights:

• Steering angle
• Yaw rate
• Status of reverse gear
  • E81, E92, E93 with start of series production and E87 from 03/2007

    Instead of the high-beam headlight (H7), the high headlight with turning light has a fixed additional reflector with an H3 bulb. The special shape of the lens prevents dazzle to the front.

The illustration shows the high headlight with turning light on the E81, E87, E92, E93

1. Bi-xenon light
2. H8 bulb for side lights and daytime driving lights
3. H3 bulb for turning lights
4. Reflector for turning lights

The following conditions 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 detects twilight or darkness (threshold exceeded)

The turning lights are not activated at speeds greater than 70 km/h.

• Europe version:

For legal reasons, the turning lights on the Europe version can only be activated via the turn signal 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: outside of turn only

When the turn signal 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/highbeam switch (up to 3 times) until the reflector has reached a certain temperature.

A temperature model protects the headlights from excessive thermal stress.

The switching-off conditions for the turning light depend on the country concerned.

• E70 with start of series production

  The turning lights are realized using the front foglights. (Reason: The installation location of the headlights is too high for the turning lights. This prevents legal stipulations from being adhered to.)

  Depending on actuation, the right-hand and/or left-hand front foglight is switched on. The turning lights are actuated by the light module (LM).

  The front foglights have an additional reflector to illuminate the areas to the sides better.

  When turning, the front foglight 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 are not switched on suddenly but rather faded according to special time parameters. Depending on the country concerned, the turning lights are switched on when cornering.

  Fig 3: Identifying Front Foglight Components

  Courtesy of BMW OF NORTH AMERICA, INC.

The following conditions 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 detects twilight or darkness (threshold exceeded)

and 

• Turn signal indicator ON (not one-touch turn signal)
• Speed range (forwards):
  • Europe and Japan 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 ≥ 10°

Alternatively 

• Speed range (reverse):
  • 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 activated again with the turn-signal/high-beam switch.

The following conditions 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 detect twilight or darkness (lower threshold exceeded)

Alternatively 

• Turn signal indicator OFF
• Speed range (forwards):
  • Europe and Japan versions ≥ 40 km/h
  • US version ≥ 70 km/h
• Swivel angle (theoretical):
  • when stationary 77°
  • when driving 10°

Alternatively 

• Speed range (reverse): ≥ 40 km/h
• Swivel angle (theoretical): when stationary and when driving below a certain value

Alternatively 

• Vehicle skids and swings out.

Alternatively 

• Front foglights are switched on with the front foglights 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.