Automatic Headlamp Levelling

Fig 1: Identifying Automatic Headlamp Levelling

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 headlamp control module (HCM) (4/118) 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) sends information to the headlamp control module (HCM) on vehicle angle as regards load conditions, acceleration and braking.

The headlamp control module (HCM) uses the information from the position sensors or suspension module (SUM) to calculate the actual angle for the headlamps.

For vehicles with active headlamps, the headlamp control module (HCM) transmits information on the actual angle to the left headlamp control unit (LHCU) and right headlamp control unit (RHCU) via serial communication. The adjustment motors are then controlled by the left headlamp control unit (LHCU) or right headlamp control unit (RHCU), respectively, via an analog signal.

For vehicles without active headlamps, the headlamp control module (HCM) regulates the relevant adjustment motor via a signal.