Apparatus and method for controlling the light-range of motor vehicle headlights

In an apparatus for control of a light-range of headlights of a motor vehicle on a road comprising at least one adjusting device connected with the headlights, said at least one adjusting device setting and adjusting an orientation of the headlights;

• at least one sensor, said at least one sensor detecting at least indirectly a load condition of the motor vehicle and producing a sensor signal depending on the load condition;
• and an analyzer/control unit connected to the at least one sensor and the at least one adjusting device, said analyzer/control unit receiving the sensor signal from the at least one sensor and controlling the adjusting device and thus the headlight orientation according to the sensor signal to maintain the light-range of the headlights substantially constant, the improvement wherein the at least one sensor is an electro-optic sensor such that the at least one sensor detects a state of light reflected from a portion of the road illuminated by the headlights in front of the motor vehicle and from obstacles located thereon;
• and the analyzer/control unit contains means for storing data including set values representing the state of the reflected light when the headlights are in a desired orientation, means for storing other data including actual values representing the state of the reflected light for an actual orientation of the headlights derived from the sensor signals from the at least one sensor when the headlights are set in the actual orientation;
• means for comparing the actual values and the set values and for forming differences therebetween;
• and means for controlling the at least one adjusting device to set the headlights in at least one other actual orientation until the differences between the set values and the actual values are minimized to determine the actual orientation of the headlights closest to the desired orientation.