Function Of Intelligent Light System - GF82.10-P-3090RD
Model 172.4 up to model year 2017
with code 615 (Bi-xenon headlamps with active light function)
with code 621 (Intelligent Light System (left-hand traffic))
with code 622 (Intelligent Light System)
Function requirements, general
- No overvoltage or undervoltage (operating voltage range U ≥ 7 ≤ 17.5 V)
- Transport mode not activated (as of 01.06.2012)
- Low beam ON
- "Engine running" or "drive train operational" signal on
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).
The front SAM control unit sends these signals via the front end CAN (CAN G) to the headlamp control unit (N71/1).
Intelligent Light System function in general
The Intelligent Light System permits optimal illumination of the roadway for different road and weather conditions.
This takes place by increasing the light output and selectively actuating additional light sources and various actuators in the left front lamp unit (E1) or in the right front lamp unit (E2).
The Intelligent Light System comprises the following subfunctions:
- Cornering lights function sequence
- Function sequence, dynamic curve illumination
- Function sequence for active light distribution (with CODE 621 (Intelligent Light System (left-hand traffic)) or CODE 622 (Intelligent Light System))
Additional function prerequisites for cornering lights
- Turn signaling active and speed v < 40 km/h (except code 494 (USA version)) or speed v < 60 km/h (with code 494 (USA version)) or steering angle recognized and speed v < 70 km/h
- Radius of curve r ≤ 80 m
Cornering lights function sequence
The cornering lights improve the illumination of the edge of the road on the inside of the curve.
The direct input factors of the cornering lights actuation are the steering wheel angle, recorded by the steering wheel angle sensor (N49), and the turn signaling function, defined by the switch position of the combination switch (S4), since they describe the driver's required direction.
The vehicle speed influences the actuation characteristic for cornering lights actuation.
At slow speed, a sensitive switch-on point is required to ensure that the cornering lights can be activated early in urban traffic.
Schematic of light distribution for active cornering lights actuation
The steering column tube module control unit (N80) directly reads in the signals from the steering wheel angle sensor and the switch position of the combination switch and sends information on the steering angle and the switch position of the combination switch via the chassis CAN, front SAM control unit, and front end CAN to the headlamp control unit.
The vehicle speed is calculated on the basis of the wheel speeds. To do so, the Electronic Stability Program control unit (N30/4) sends corresponding data via the chassis CAN to the instrument cluster (A1) and via the chassis CAN, front SAM control unit, and front end CAN to the headlamp control unit. The instrument cluster calculates the vehicle speed to be displayed and sends this via the chassis CAN, front SAM control unit, and front end CAN to the headlamp control unit.
The headlamp control unit then actuates the left cornering light (E1e9) or right cornering light (E2e9); the light on the inside of the curve during forward travel and the light on the outside of the curve during reverse travel.
If there is a rapid change in the steering wheel angle or in the turn signaling request, both corner-illuminating fog lamps may illuminate briefly. The corresponding cornering light is switched on and off with dimming.
The request by the turn signaling function has a higher priority at a speed of v < 40 km/h than the request by the detection of the steering wheel angle in order to ensure the illumination of the edge of the road on the inside of the curve when the steering wheel is turned and turning in the opposite direction (situation in rotaries).
When the reverse gear is engaged, only the data of the steering wheel angle sensor is evaluated.
The "reverse gear engaged" status is defined as follows.
Vehicles with transmission 711 (manual transmission):
Reverse gear engagement is defined by the status of the backup lamp switch (S16/2). The front SAM control unit reads in the status of the backup lamp switch directly.
Vehicles with transmission 716.7 (manual transmission):
Engaging the reverse gear is detected by the manual transmission main shifter shaft position sensor (B79/3). The ME-SFI [ME] control unit directly reads in the signals from the manual transmission main shifter shaft position sensor and sends them via the chassis CAN to the front SAM control unit.
Vehicles with transmission 722.9, 725.0 (automatic transmission):
The request to engage "Gear range R" is defined by the corresponding selector lever position.
The electronic selector lever module control unit (N15/5) (transmission 722.9) or the DIRECT SELECT INTERFACE (N150) (transmission 725.0) transmits the selector lever position via the drive train CAN (CAN C), the CDI control unit, or the ME-SFI [ME] control unit and the chassis CAN to the front SAM control unit.
Two microprocessors are installed in the front SAM control unit, one for control of basic functions, e.g. the exterior lights, and the second for control of the central gateway functions. Both processors communicate with each other internally via the interior CAN (CAN B).
The microprocessor for controlling the central gateway functions uses all incoming information to generate the "reverse gear engaged" signal (irrespective of the transmission variant) and sends this signal via the front end CAN to the headlamp control unit.
When the cornering lights function is requested at the same time by the steering wheel angle detected and the turn signaling function, the corresponding cornering light is actuated already at a curve radius of r ≤ 450 m.
When the function request suddenly no longer exists, the corresponding cornering light remains switched on for a holding time of approx. t = 2 s and is switched off within t = 2 s with dimming.
Additional function requirements for dynamic curve illumination
- Function "Intell. Light System:" activated in the "Lights" menu in the instrument cluster
The selection of the function is made through the controls in the instrument cluster. The instrument cluster transmits the corresponding status via chassis CAN to the front SAM control unit.
- Vehicle moving forward
- Extended fog light function disabled
Function sequence, dynamic curve illumination
Dynamic curve illumination improves the road illumination when cornering. For this the low beam cone is swiveled horizontally towards the center point of the curve.
A conventional bi-xenon headlamp serves as a basis, the headlamp unit of which is supported in a retaining frame so that it can swivel. When steering into a curve, the headlamp unit on the inside of the curve is swiveled up to α = 15°, the headlamp unit on the outside of the curve up to α = 7.5°.
Schematic of light distribution for active dynamic curve illumination function
The dynamic curve illumination depends on the following control variables:
- Steering wheel angle
- Vehicle speed
- Movement (yaw behavior) of vehicle
The direct input factor is the steering angle; the vehicle speed influences the control response of the function (ratio of steering angle to swivel angle).
At a low vehicle speed, a smaller ratio is required so that the light pattern does not behave in a jumpy manner (e.g. in urban traffic). At medium speeds an immediate response is given to relatively minor changes in the steering angle and at higher speeds the responses are dampened again to a greater extent. To compensate for the weaving of the vehicle when driving straight ahead, an area with lower sensitivity and enhanced damping has been provided (approx. ± 6° steering wheel angle).
The steering column tube module control unit directly reads in the signals from the steering wheel angle sensor and sends information about the steering angle via the chassis CAN, front SAM control unit, and front end CAN to the headlamp control unit.
The Electronic Stability Program control unit sends information on vehicle movements via the chassis CAN, front SAM control unit, and front end CAN to the headlamp control unit.
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, this is designed as a separate component and communicates with the Electronic Stability Program control unit via the vehicle dynamics CAN (CAN H). In vehicles for which the above-mentioned limitation does not apply, the turn rate sensor for lateral and longitudinal acceleration is integrated in the Electronic Stability Program control unit.
The instrument cluster sends the vehicle speed via the chassis CAN, front SAM control unit, and front end CAN to the headlamp control unit.
The headlamp control unit actuates the left active curve lights actuator motor (E1m2) via the left headlamp LIN (LIN G1) and the right active curve lights actuator motor (E2m2) via the right headlamp LIN (LIN G2).
The position of the active curve lights actuator motors at any given time and any faults that occur, such as short circuits or open circuits, are reported back to the headlamp control unit.
If the curve illumination actuation is defective, the headlamp units are, if possible, swiveled into the central position.
Additional function requirements for active light distribution (with CODE 621 (Intelligent Light System (left-hand traffic)) or CODE 622 (Intelligent Light System))
- Vehicle moving forward
Function sequence for active light distribution (with CODE 621 (Intelligent Light System (left-hand traffic)) or CODE 622 (Intelligent Light System))
Active light distribution encompasses the following subfunctions:
- Function sequence for motorway lights
- Function sequence for extended fog light
The function sequences are described using a left-hand drive vehicle as an example.
Additional function requirements, freeway lights
- Function "Intell. Light System": activated in the "Settings", "Lights" menu in the instrument cluster
- Extended fog light function inactive
Function sequence for motorway lights
The freeway lights improve the illumination of the road by increasing the range of the low beams without blinding the preceding traffic.
This function is achieved by means of vertically deflecting the light cone and increasing the light output.
The freeway lights are activated at speeds Modelical for the freeway or expressway.
The motorway lights function is deactivated when it is raining. Rain detection takes place by evaluating the windshield wiper signal (windshield wiper not in park position).
If the windshield wiper is in the park position less than t = 0.6 s, this is evaluated as continuous wipe. Rain is detected if the continuous wipe function is active for t > 2 min.
Schematic of light distribution for active freeway lights function
The motorway lights function depends on the following control factors:
- Steering wheel angle
- Vehicle speed
- Yaw characteristics of the vehicle
The steering column tube module control unit directly reads in the signals from the steering wheel angle sensor and sends information about the steering angle via the chassis CAN, front SAM control unit, and front end CAN to the headlamp control unit.
The Electronic Stability Program control unit sends information on vehicle movements via the chassis CAN, front SAM control unit, and front end CAN to the headlamp control unit.
The instrument cluster sends the vehicle speed via the chassis CAN, front SAM control unit, and front end CAN to the headlamp control unit.
Starting at a vehicle speed of v > 90 km/h and a curve radius of r > 800 m for a driving distance of more than s = 2.5 km, the light output of the left xenon bulb with integrated ignition module (E1e10) and the right xenon bulb with integrated ignition module (E2e10) is increased linearly up to P = 38 W by the headlamp control unit. To this end, the headlamp control unit transmits a request to increase the light output over the left headlamp LIN to the left xenon light power supply module (E1n4) and over the right headlamp LIN to the right xenon light power supply module (E2n4).
Starting at a vehicle speed of v > 110 km/h and a curve radius of r > 800 m for a driving distance of more than s = 1 km, the headlamp control unit actuates the left light distribution actuator motor (E1m3) via the left headlamp LIN.
The roller that partially covers up the light cone of the xenon bulb is rotated accordingly, thereby increasing the range of the low beams. Maximum release of the xenon lamp light cone is reached at v = 130 km/h.
If the vehicle speed drops to below v = 80 km/h, the motorway lights function is deactivated.
In left-hand traffic, the corresponding actuator in the right front lamp unit is actuated.
Additional function requirements for extended fog light function
- Function "Intell. Light System:" activated in the "Lights" menu in the instrument cluster
- Rear fog lights actuation active
Function sequence for extended fog light
The extended fog light function improves the illumination of the edges of the road and reduces the internal dazzling.
It is activated at speeds Modelical of urban traffic and rural roads.
The headlamp unit of the front lamp unit facing the inside of the road is raised and swiveled outwards at vehicle speeds below v = 70 km/h.
Schematic of light distribution for active extended fog light function
The front SAM control unit directly reads in the status of the rear fog light button (S1s10), sends this via the front end CAN to the headlamp control unit, and activates the rear fog light actuation.
The headlamp control unit actuates the left headlamp range adjustment actuator motor (E1m1) and the left active curve lights actuator motor via the left headlamp LIN.
The headlamp unit of the left front lamp unit is raised and swiveled outwards by α = 8°.
Internal dazzling is reduced and illumination of the road surface at the side is improved.
If the extended fog light function is active, the dynamic curve illumination is deactivated.
If the high beams function is requested while the "Extended fog light function" is active, the position of the headlamp unit is retained.
The left daytime running lights headlamp (E1/3) and the right daytime running lights headlamp (E2/3) are switched off to prevent possible reflective glare.
In left-hand traffic, the corresponding actuator in the right front lamp unit is actuated.
The extended fog light function is deactivated under the following conditions:
- Failure of a front lamp unit (low beam)
- Malfunction in left headlamp range adjustment servomotor or left active curve illumination servomotor
When testing and adjusting the front lamp unit, ensure that the extended fog light function is not active.
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