Automatic Headlight Levelling

Fig 1: Identifying Automatic Headlight Levelling Components

Courtesy of VOLVO CARS CORPORATION

For vehicles without Four-C (Continuously Controlled Chassis Concept), the position sensors (7/119, 7/121) for rear wheel suspension and front wheel suspension send information to the Central electronic module (CEM) (4/56) on vehicle angle as regards load conditions, acceleration and braking.

For vehicles with Four-C (Continuously Controlled Chassis Concept), the Suspension module (SUM) (4/84) transmits information to the Central electronic module (CEM) about vehicle angle as regards load conditions, acceleration and braking.

The Central electronic module (CEM) uses the information from the position sensors or suspension module (SUM) to calculate the actual angle for headlamp levelling.

The Central electronic module (CEM) transmits information on the actual angle to the left headlamp control unit (LHCU) and right headlamp control unit (RHCU) via serial communication. The actuator motors are then controlled by the left headlamp control unit (LHCU) or right headlamp control unit (RHCU), respectively, via an analogue signal.