Function Of Adaptive High Beam Assist - GF82.10-P-3091RD
Model 172.4 up to model year 2017
with code 608 (Adaptive High Beam Assist)
Function requirements, general
- No overvoltage or undervoltage
- Transport mode not activated
- "Engine running" or "drive train operational" signal on
- Function activated via the instrument cluster (A1)
- Low beam ON
- Combination switch (S4) in "High beams" position
The CDI control unit (N3/9) (diesel engine) or ME-SFI [ME] control unit (N3/10) (gasoline engine) sends the "engine running" or "drivetrain operational" signal via the chassis CAN (CAN E) to the front SAM control unit with fuse and relay module (N10/1) and to the multifunction camera (A40/11).
The function can be selected via the controls in the instrument cluster. The instrument cluster sends the corresponding status via interior CAN (CAN B) to the front SAM control unit.
The steering column tube module control unit (N80) directly reads in the switch position of the combination switch and sends this via the chassis CAN to the front SAM control unit.
The front SAM control unit, as the master control unit for the exterior lights, reads in the function requirements, evaluates them, and sends the release for the Adaptive High Beam Assist function via the chassis CAN to the multifunction camera.
The multifunction camera is the master control unit for the Adaptive High Beam Assist.
Adaptive High Beam Assist, general
The traffic and environment situation in front of the vehicle is detected by the multifunction camera and accordingly evaluated. Actuating the actuators integrated in the left front lamp unit (E1) and the right front lamp unit (E2) serves to ensure that the road is ideally illuminated without dazzling any of the other road users. The multifunction camera uses the brightness, shape, structure, color, where applicable, and motion of detected objects to differentiate between preceding or oncoming road users, street lighting, signs or other parts of the environment. The picture recognition module integrated into the multifunction camera judges the distance, e.g. to other road users, evaluates the outside brightness level of the vehicle environment and recognizes extreme weather conditions (e.g. thick fog, heavy snowfall) or tunnels.
The activated Adaptive High Beam Assist function is displayed by a symbol in the multifunction display (A1p13) in the instrument cluster. The front SAM control unit sends the "Adaptive High Beam Assist active" status via interior CAN to the instrument cluster for this.
Function sequence for Adaptive High Beam Assist
The multifunction camera evaluates the following information to implement the function, among other things:
- Steering angle
- Vehicle speed
- Yaw behavior (movement of vehicle)
The steering column tube module control unit directly reads in the data from the steering wheel angle sensor (N49), calculates the steering angle, and sends this via the chassis CAN to the multifunction camera.
The vehicle speed is calculated on the basis of the wheel speeds. The Electronic Stability Program control unit (N30/4) sends information on the wheel speeds via the chassis CAN to the multifunction camera.
Information on the vehicle's motion is sent by the Electronic Stability Program control unit via the chassis CAN to the multifunction camera.
The yaw behavior of the vehicle is detected by the turn rate sensor for lateral and longitudinal acceleration (B24/15). In vehicles with code 233 (DISTRONIC PLUS) and in model 172.475, it is designed as a separate component and communicates via vehicle dynamics CAN (CAN H) with the Electronic Stability Program control unit. For vehicles, for which the above-mentioned limitation does not apply, the yaw rate sensor for lateral and longitudinal acceleration is integrated into the Electronic Stability Program control unit.
A differentiation is made between the following Adaptive High Beam Assist functional states:
- Optical headlamp range adjustment (from v > 25 km/h)
The headlamp range of the low beam is automatically adapted to the distance to other road users.
- Automatic high beams (from v > 55 km/h)
The high beams are activated if no other road user is detected.
Schematic representation, shown on model 204
Optical headlamp range adjustment (from v > 25 km/h)
Depending on the distance of the vehicle to other road users and the geometry of the road (differences in height, angle), the multifunction camera sends the "Optical headlamp range adjustment" request via the chassis CAN, front SAM control unit, and front end CAN (CAN G) to the headlamp control unit (N71/1).
The headlamp control unit then actuates the left headlamp range adjustment actuator motor (E1m1) via the left headlamp LIN (LIN G1) and the right headlamp range adjustment actuator motor (E2m1) via the right headlamp LIN (LIN G2).
The low beam cones are moved vertically upwards, thereby providing better road illumination without dazzling other road users. The light cone of the headlamps varies between s = 65 m (standard lighting) and s = 300 m.
If the vehicle speed drops below v = 40 km/h, the "optical headlamp range adjustment" is deactivated.
Automatic high beams (from v > 55 km/h)
If no other road users are detected, the multifunction camera activates the automatic high beams function.
The multifunction camera sends the "automatic high beams On" request via the chassis CAN, front SAM control unit, and front end CAN to the headlamp control unit.
The headlamp control unit actuates the left light distribution actuator motor (E1m3) via the left headlamp LIN and the right light distribution actuator motor (E2m3) via the right headlamp LIN.
The rollers that partially cover up the light cone of the xenon bulbs are turned, thereby uncovering the entire light beam to illuminate the traffic lane.
If the vehicle speed sinks below v = 45 km/h, the automatic high beams are deactivated.
The activation or deactivation speed of the automatic high beams is controlled adaptively by the multifunction camera.
As soon as the automatic high beams are activated, the high beams indicator lamp (A1e3) in the instrument cluster lights up. The front SAM control unit sends the corresponding request via the interior CAN to the instrument cluster.
On roads with street lamps positioned regularly, the automatic high beams are deactivated.
Adaptive High Beam Assist limits:
In tight curves, the multifunction camera may not recognize oncoming vehicles or only do so very late due to the detection angle (α = 35°).
On streets with structural separation (e.g. guardrails on freeways) the headlamps of oncoming vehicles are often concealed. These vehicles are not recognized by the multifunction camera. The automatic high beams are not switched off.
Due to the geometry of the structural separation and the location of the headlamps on cars, the drivers of the oncoming cars are not dazzled. Truck drivers, however, are dazzled due to the high seat position. The clearance lamps on trucks are not sufficient for recognition.
The automatic high beams are deactivated depending on the steering angle.
When driving over crests, oncoming vehicles are not recognized until late and the automatic high beams are therefore also switched off later. In this situation, however, the driver of the oncoming vehicle is also dazzled by the low beams.
Lights that are visible for a long time and that slowly become brighter (e.g. with partial concealment of the headlamps by trees) make it more difficult to recognize oncoming vehicles.
With bright lights that appear suddenly (e.g. street lamps, traffic lights, lot illumination), the automatic high beams are deactivated.
Some reflectors cannot be clearly differentiated by road users (e.g. motorcyclists). The automatic high beams are deactivated because of the existing danger of dazzling other road users.
| Function schematic for Adaptive High Beam Assist | PE82.10-P-2066-97TAA | ||
| Overview of exterior lights system components | GF82.10-P-9998RD |