Sensorless control of a rotary valve actuator for combustion engines

A robust sensorless control system to use in an electromotive valve actuator for combustion engines is described. The mechanical setup of a rotary valve actuator, which transfers the angular force by a bell crank to the valves, combines the advantage of variable mechanical and electromechanical valve drives because of adjustable stroke and opening time. The option to control several valves by a single actuator, to apply a single phase power supply and to operate the system without position sensor reduces the electronic equipment drastically. Further, low inertia and supporting springs minimize the power consumption.