Function of Adaptive Highbeam Assist - GF82.10-P-3091FLM

MODEL 212 as of model year 2014 with CODE 608 (Automatic high beam control)

MODEL 212 as of model year 2014 with CODE 628 (INTELLIGENT HEADLAMP CONTROL PLUS (IHC+))

Function requirements, general

No overvoltage or undervoltage (operating voltage range U ≥ 7 ≤ 17.5 V)
Transport mode not activated
"Engine running" or "drive train operational" signal on
Function in instrument cluster (A1) activated
Low beams ON (exterior lights switch (S1) in "AUTO" position and rain/light sensor (B38/2) detects darkness)
Combination switch (S4) in "High beams" position

Detailed information on the operating state of the transport mode is given in the separate function description for energy management. The function requirements are read in as follows:

The CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) sends the "Engine running" or "Drivetrain operational" signal via chassis CAN 1 (CAN E1) to the front SAM control unit with fuse and relay module (N10/1).

The Adaptive Highbeam Assist function is manually enabled using the control level in the instrument cluster. The instrument cluster sends the corresponding status via interior CAN (CAN B) to the front SAM control unit.

The "Low beams ON" status is generated by the front SAM control unit itself. To do so, the front SAM control unit reads in the status of the exterior lights switch directly and the rain/light sensor data via the wiper/inside rearview mirror LIN (LIN 2). The low beams indicator lamp (A1e67) in the instrument cluster is actuated in every functional state. To this end, the front SAM control unit sends the "Switch on low beams indicator lamp" request via interior CAN to the instrument cluster.

The steering column tube module control unit (N80) reads in the switch position of the combination switch directly and sends this via chassis CAN 1 to the front SAM control unit.

The front SAM control unit is the master control unit for the exterior lights. The front SAM control unit reads in the function requirements and enables the multifunction camera (A40/11) (on vehicles without code (23P) Driving assistance package) or the stereo multifunction camera (A40/13) (on vehicles with code (23P) Driving assistance package). The multifunction camera (on vehicles without code (23P) Driving assistance package) or the stereo multifunction camera (on vehicles with code (23P) Driving assistance package) is the master control unit for the Adaptive Highbeam Assist.

Adaptive Highbeam Assist, general

The traffic situation or the situation of the surrounding area in front of the vehicle is recorded and evaluated by the multifunction camera (on vehicles without code (23P) Driving assistance package) or the stereo multifunction camera (on vehicles with code (23P) Driving assistance package). 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 (on vehicles without code (23P) Driving assistance package) or the stereo multifunction camera (on vehicles with code (23P) Driving assistance package) uses the brightness, form, structure and, where applicable, color and motion of the detected objects to determine whether the objects are road users traveling ahead or oncoming road users, street lights, signs or other parts of the infrastructure. The image detection module integrated in the multifunction camera (on vehicles without code (23P) Driving assistance package) or in the stereo multifunction camera (on vehicles with code (23P) Driving assistance package) assesses the distances, e.g. to other road users, evaluates the external brightness of the vehicle surroundings and detects any extreme weather conditions (e.g. thick fog, heavy snowfall) as well as passages through tunnels. To implement the function, the multifunction camera (on vehicles without code (23P) Driving assistance package) or the stereo multifunction camera (on vehicles with code (23P) Driving assistance package) also evaluates the following information:

Steering angle
Vehicle speed
Yaw behavior

The data of the steering angle sensor (N49) is read in directly by the steering column tube module control unit and it sends this via chassis CAN 1, the front SAM control unit and chassis CAN 2 (CAN E2) to the multifunction camera (on vehicles without code (23P) Driving assistance package) or chassis CAN 2, the chassis gateway control unit (N93/7) and the chassis FlexRay (Flex E) to the stereo multifunction camera (on vehicles with code (23P) Driving assistance package).

The vehicle speed is calculated on the basis of the wheel speeds. To this end, the Electronic Stability Program control unit (N30/4) (model 212 (except 212.074/092/095/098/274/292/298) without code (233) DISTRONIC PLUS), the regenerative braking system control unit (N30/6) (model 212.095/098/298) or the Premium Electronic Stability Program control unit (N30/7) (model 212 (except 212.095/098/298) with code (233) DISTRONIC PLUS, model 212.074/092/274/292) sends corresponding data via chassis CAN 1 and front SAM control unit and chassis CAN 2 to the multifunction camera (on vehicles without code (23P) Driving assistance package) or chassis CAN 2, the chassis gateway control unit and the chassis FlexRay to the stereo multifunction camera (on vehicles with code (23P) Driving assistance package).

The yaw behavior of the vehicle is detected by the yaw rate sensor for lateral and longitudinal acceleration (B24/15). This then sends corresponding information via vehicle dynamics CAN (CAN H), Electronic Stability Program control unit or regenerative braking system control unit, chassis CAN 1, front SAM control unit and chassis CAN 2 to the multifunction camera (on vehicles without code (23P) Driving assistance package) or chassis CAN 2, the chassis gateway control unit and the chassis FlexRay to the stereo multifunction camera (on vehicles with code (23P) Driving assistance package).

A differentiation is made between the following Adaptive Highbeam Assist functional states:

Optical headlamp range adjustment (as of approx. v = 25 km/h)
The headlamp range of the low beam is automatically adapted to the distance of the vehicles.
Automatic high beams (as of approx. v = 30 km/h)
If no other road users are detected, the high beams are activated.
Partial high beam (as of approx. v = 45 km/h) (with code (628) (AUTOMATIC HIGH BEAM CONTROL PLUS (IHC+)
With the partial high beam function, other road users are not dazzled. The road users are located in the low beam section of the light cone and thereby omitted from the high beam.

Fig 1: Identifying Headlamp Beam
Courtesy of MERCEDES-BENZ USA

Optical headlamp range adjustment (as of approx. v = 25 km/h)

Depending on the distance of the vehicle to other road users and the road geometry (height differences, angles), the multifunction camera (on vehicles without code (23P) Driving assistance package) or the stereo multifunction camera (on vehicles with code (23P) Driving assistance package) sends the "Optical headlamp range adjustment" request to the left headlamp control unit (E1n9) and the right headlamp control unit (E2n9). The multifunction camera (on vehicles without code (23P) Driving assistance package) sends the request via chassis CAN 2 to the headlamp control units, the stereo multifunction camera (on vehicles with code (23P) Driving assistance package) sends the request via chassis FlexRay, chassis gateway control unit and chassis CAN 2 to the headlamp control units.

The left headlamp control unit actuates the left headlamp range adjustment actuator motor (E1m1) directly and actuates the "low beam" in the left front Vario LED lamp unit (E1e22) via the left headlamp LIN (LIN G1) and the left front LED exterior lights actuation module (E1n7).

The right headlamp control unit actuates the right headlamp range adjustment actuator motor (E2m1) directly and actuates the "low beam" in the right front Vario LED lamp unit (E2e22) via the right headlamp LIN (LIN G2) and the right front LED exterior lights actuation module (E2n7).

The headlamp units of the front lamp units are raised accordingly. The road surface is better illuminated without causing a dazzling effect for other road users.

The headlamp light cone varies between s = 65 m (standard lighting) and s = 300 m.

Automatic high beams (as of approx. v = 30 km/h)

If no other road users are detected by the multifunction camera (on vehicles without code (23P) Driving assistance package) or by the stereo multifunction camera (on vehicles with code (23P) Driving assistance package) then the automatic high beams are activated. The multifunction camera (on vehicles without code (23P) Driving assistance package) sends the "High beams ON" request via chassis CAN 2 to the headlamp control units, the stereo multifunction camera (on vehicles with code (23P) Driving assistance package) sends the "High beams ON" request via chassis FlexRay, chassis gateway control unit and chassis CAN 2 to the headlamp control units. The activated automatic high beams function is visually indicated to the driver. To this end, the front SAM control unit sends the "High beams ON" request via interior CAN to the instrument cluster. The instrument cluster actuates the high beams indicator lamp (A1e3).

The left headlamp control unit actuates the left light distribution actuator motor (E1m3) directly and actuates the "high beam" in the left front Vario LED lamp unit via the left headlamp LIN and the left front LED exterior lights actuation module.

The right headlamp control unit actuates the right light distribution actuator motor (E2m3) directly and actuates the "high beam" in the right front Vario LED lamp unit via the right headlamp LIN and the right front LED exterior lights actuation module.

On roads with street lamps positioned regularly, the automatic high beams are deactivated.

Partial high beam (as of approx. v = 45 km/h) (with code (628) (AUTOMATIC HIGH BEAM CONTROL PLUS (IHC+)

Fig 2: Overview Of LED Exterior Lights Actuation Module

Courtesy of MERCEDES-BENZ USA

If other road users are detected by the multifunction camera (on vehicles without code (23P) Driving assistance package) or by the stereo multifunction camera (on vehicles with code (23P) Driving assistance package), the partial high beam function is activated. The activated partial high beams function is visually indicated to the driver. To this end, the front SAM control unit sends the "High beams ON" request via interior CAN to the instrument cluster. The instrument cluster actuates the high beams indicator lamp.

The left headlamp control unit actuates the left light distribution adjustment actuator motor directly.

The left headlamp control unit increases the light output of the "high beam" in the left front Vario LED lamp unit via the left headlamp LIN and the left front LED exterior lights actuation module.

The right headlamp control unit actuates the right light distribution adjustment actuator motor directly.

The right headlamp control unit increases the light output of the "high beam" in the right front Vario LED lamp unit via the right headlamp LIN and the right front LED exterior lights actuation module.

Limits of the system

In tight corners, the multifunction camera (on vehicles without code (23P) Driving assistance package) or the stereo multifunction camera (on vehicles with code (23P) Driving assistance package) is unable to detect oncoming vehicles or it only detects them at a very late stage because of the detection angle (∠ = 35°).

On streets with structural separation (e.g. guardrails on freeways) the headlamps of oncoming vehicles are often concealed. These vehicles are not detected by the multifunction camera (on vehicles without code (23P) Driving assistance package) or by the stereo multifunction camera (on vehicles with code (23P) Driving assistance package).

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.

When driving over hills, oncoming vehicles are not recognized until late and the 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, illumination of lots), the high beams are deactivated.

Some reflectors cannot be clearly differentiated by road users (e.g. motorcyclists). The high beams are deactivated because of the danger of dazzling other road users.

	Function schematic for Adaptive Highbeam Assist		PE82.10-P-2066-97DAB
	Overview of exterior lights system components		GF82.10-P-9998FLM