High-Beam Assistant

High-Beam Assistant

High-beam assistant
The high-beam assistant (FLA) in the E70 supports the driver with operation of the high-beam headlight. The high-beam assistant automatically switches the high-beam headlight on and off depending on the traffic situation. The high-beam assistant detects oncoming vehicles and vehicles up ahead as well as consistently illuminated built-up areas.

Brief description of components
The following components are described for the high-beam assistant:
- Light switch
- Steering column switch cluster (SZL)
- Rain/light solar sensor (RLSS)
- Roof control panel (FZD)
- Instrument cluster
- Image sensor
- Dynamic Stability Control (DSC)
- Footwell module (FRM)
- Junction box electronics (JBE)

Light switch
The high-beam assistant can be activated only when the light switch is in position "A". The switch position "A" stands for automatic driving light control.

Steering column switch cluster (SZL)
The high-beam assistant is activated and deactivated by means of the turn-signal/high-beam switch in the SZL. The switch signals from the turn-signal/high-beam switch are picked up and evaluated by the SZL. The SZL sends the switch signals from the turn indicator-high-beam switch directly to the footwell module (FRM).

Rain/light solar sensor (RLSS)
The RLSS measures the surrounding brightness. From dusk onwards, the footwell module (FRM) switches the low-beam headlight on. The high-beam assistant (FLA) can be activated only when the dipped headlights are on. The precondition is that the light switch must be in the "A" position. The RLSS sends its information vie the LIN bus to the roof function centre (FZD).

Roof control panel (FZD)
The FZD processes the information from the RLSS. The FZD signals to the footwell module (FRM) the switch-on condition for the RLSS via the K-CAN.

Instrument cluster
The instrument cluster accommodates the following displays:
- High-beam indicator light (blue)
- High-beam assistant indicator light (orange)
- Check Control symbol for failure of the high-beam assistant (yellow)

Image sensor
The image sensor is a special camera for detecting light sources. The image sensor transfers images to the high-beam assistant (FLA). The images are carried by an LVDS data line (LVDS: Low Voltage Differential Signalling).
The FLA evaluates these images. The FLA sends a switch-on or switch-off recommendation for the high-beam headlight via the K-CAN to the footwell module (FRM). The recommendation depends on the traffic situation, the ambient light, and the car's road speed.

Dynamic Stability Control (DSC)
The DSC control unit calculates the car's road speed using the signals from the wheel-speed sensors. The DSC uses the signal from the DSC sensor to calculate the yaw rate. The high-beam assistant uses the information on the yaw rate to improve evaluation when the car corners. The DSC sends the results of the calculation of driving speed and yaw rate via the PT-CAN to the junction box electronics (JBE).

Footwell module (FRM)
The FRM receives various input variables for the high-beam headlight.
The following input variables are processed by the FRM:
- Switch-on or switch-off recommendation from the high-beam assistant (FLA).
- Switch position of the light switch
- Switch position of the direction indicator/high-beam switch
- Information from the reverse gear switch or selector lever position switch
- Information from the rain/light solar sensor (RLSS).

On the basis of the input variables, the FRM decides whether the high-beam headlights should be switched on or off. The FRM activates the high-beam headlights. The FRM actuates the indicator light in the instrument cluster. A Check Control symbol appears if the high-beam assistant fails. The FRM is connected to the K-CAN.

Junction box electronics (JBE)
The JBE receives the calculations from the DSC via the PT-CAN. The JBE sends its information via the K-CAN to the FRM.












System functions
In accordance with the traffic situation, the high-beam assistant sends a switch-on recommendation or a switch-off recommendation for the high-beam headlights to the FRM. On the basis of this recommendation and various other the input variables, the FRM decides whether the high-beam headlights should be switched on or off.

Conditions required for switch-on for the high-beam assistant:
- Light switch set to position "A"
- Dipped headlights switched on.
- Turn-signal/high-beam switch pressed forward (in forward direction of travel).

Switch-on conditions for the high-beam headlight with the highbeam assistant:
- Road speed greater than 50 km/h.
- Reverse gear must not be engaged.
- Image sensor does not detect an oncoming vehicle or a vehicle ahead.
- Image sensor detects adequate darkness.

The following system functions are described for the high-beam assistant:
- Automatic high-beam headlight switch-off when oncoming traffic is detected.
- Automatic high-beam headlight switch-off when vehicle detected ahead of the car
- Automatic high-beam headlight switch-off when adequate ambient lighting is detected
- Automatic high-beam headlight switch-on.
- Indicators in the instrument cluster.
- Function limitations of the high-beam assistant.
- Automatic alignment of the high-beam assistant.







Automatic high-beam headlight switch-off when oncoming traffic is detected
The light cone of the high-beam headlights has a range of about 400 m. The image sensor can detect other light sources within a range of about 1000 m. This ensures that the image sensor detects oncoming vehicles before their drivers can be dazzled by the light cone of the high-beam headlights. When the image sensor detects an oncoming vehicle, the FLA control unit sends a switch-off recommendation to the FRM. The FRM switches off the high-beam headlights.

Automatic high-beam headlight switch-off when vehicle detected ahead of the car
When the image sensor detects a vehicle ahead, the FLA control unit sends a switch-off recommendation to the FRM. The FRM switches off the high-beam headlights.

Automatic high-beam headlight switch-off when adequate ambient lighting is detected
When the image sensor detects an environment in which ambient lighting is adequate, the FLA control unit sends a switch-off recommendation to the FRM. The FRM switches off the high-beam headlights. Adequate ambient lighting means:
- Daylight
- Twilight
- Street lighting (e. g. in illuminated towns)

Automatic high-beam headlight switch-on
If there is no reason for the lights to be dipped, the FRM switches on the high-beam headlights. The high-beam headlights are reactivated.

Indicators in the instrument cluster
The high-beam assistant indicator lamp in the instrument cluster lights up as soon as the high-beam assistant (FLA) is activated. The high-beam indicator light also lights up (blue) in the usual way as soon as the high-beam headlights are switched on. A Check Control symbol appears (yellow) if the FLA detects a system failure.

Function limitations of the high-beam assistant
The high-beam assistant (FLA) can be subject to function limitations under the following circumstances:
- Unfavorable weather conditions
- Poorly illuminated road users
- Certain road signs
- Driving over crests and through dips
- Concealed field of view of the image sensor

Automatic alignment of the high-beam assistant
In order to ensure perfect function of the high-beam assistant, the image sensor must be aligned parallel to the centre axis. When the car is driven at night, the high-beam assistant can automatically correct alignment up to 3° to the left or 3° to the right. This correction com pensates for minor deviations from the centre line. Driving conditions for automatic directional orientation of the high-beam assistant are:
- Driving on a relatively straight stretch of road for a distance of approx. 50 km. A straight stretch of road shortens the time for automatic alignment.
- Road marking must be clearly visible.

No liability can be accepted for printing or other errors. Subject to changes of a technical nature