Headlights for targeted illumination

The headlights are fitted instead of the fog lights.

Each headlight for targeted illumination consists out of the following components:

• Housing
• Control unit for left-hand targeted illumination (GZAL) or right (GZAR)
• Stepper motor
• Light-emitting diodes for the positioning light
• Light-emitting diodes for the function indicator light
• Lens
• Temperature sensor

The positioning light is switched on with the switch on of the driving light. When the preconditions have been given for the switch on of the driving light, the footwell module (FRM) or the Body Domain Controller (BDC) transmits a request, as a message on the data bus, to the night vision electronics (NVE). The NVE transmits a message to the control unit for the left-hand targeted illumination (GZAL) and to the control unit for right-hand targeted illumination (GZAR). These turn on the in-series-connected light-emitting diodes of the positioning light in the headlights. Thereby, the lens is illuminated.

The control unit for the left-hand targeted illumination (GZAL) or control unit for the right-hand targeted illumination (GZAR) also evaluates all relevant input signals from other control units. When the preconditions for a switch on or off of the function indicator lights have been given, the control unit GZAL or GZAR shifts the function indicator light on or off. At the same time, the control unit GZAL or GZAR activates the stepper motor. Each headlight is equipped with a stepper motor. With it, each headlight can be individually horizontally tilted within an established movement range. By doing this, persons be illuminated through targeting. Each headlight can only illuminate one person. In the process, only the person with the highest danger potential is illuminated. The calculation takes place in the night vision electronics (NVE).

There is an overheating protection in order to prevent excess temperature in the headlights. A temperature sensor records the temperature at the function indicator light. The heating of the stepper motor is calculated continuously on the basis of the operating period (operating time and rest phase) by means of a thermal model in the control unit GZAL or GZAR. In the process, the actual outside temperature value is also taken into account.

After a certain temperature threshold, the control unit GZAL or GZAR switches off the concerned headlight. Once below a specific temperature value, the control unit GZAL or GZAR switches the headlight on again.

The graphic below shows an example of the headlight for right-hand targeted illumination F01.

Fig 1: Identifying Headlight Components

Courtesy of BMW OF NORTH AMERICA, INC.