Automatic headlight beam throw adjustment

As standard, vehicles with LED headlights have automatic headlight beam throw adjustment to compensate different load statuses of the vehicle. The automatic headlight beam throw adjustment for the LED headlight includes the following functions:

• Dynamic headlight beam throw adjustment

  The dynamic headlight beam throw adjustment was developed for compensating pitching movements that occur as a result of braking and acceleration.

• Adaptive headlight beam throw adjustment

  The adaptive headlight beam throw adjustment uses vehicle information to identify driving over rises or dips. The headlights are turned appropriately. The automatic headlight beam throw adjustment thus ensures that oncoming traffic is not dazzled.

The automatic headlight beam throw adjustment is supported by 2 ride height sensors. one ride height sensor each located on the front axle and the rear axle of the vehicle. Data from ride height sensors are evaluated directly by the Integrated Chassis Management (ICM).

The footwell module (FRM) receives the signals from the Integrated Chassis Management (ICM) via the CAN bus. The Integrated Chassis Management issues the signal as a message on the FlexRay. The signal is transferred by the FlexRay on the CAN bus in the central gateway module (ZGM).

The Body Domain Controller (BDC) receives the signals from the Integrated Chassis Management (ICM) via the LIN bus. The following graphic shows the light cone's primary motion patterns during operation of the automatic headlight beam throw adjustment.

Fig 1: Adjusting Adaptive Headlight Beam Throw

Courtesy of BMW OF NORTH AMERICA, INC.

The adaptive headlight beam throw adjustment is employed when driving through dips and over crests. Depending on the request from the footwell module (FRM) or the Body Domain Controller (BDC), the headlight driver module controls the swivel module using the stepper motors and therefore controls the headlight beam throw of the headlight.

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.

Fig 2: Adjusting Adaptive Headlight Beam Throw (Driving Through Dips And Over Crests)

Courtesy of BMW OF NORTH AMERICA, INC.

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.

Fig 3: Adjusting Adaptive Headlight Beam Throw (Vehicle Passes Over Crest)

Courtesy of BMW OF NORTH AMERICA, INC.