Output observer based feedback for soft landing of electromechanical camless valvetrain actuator

Electromechanical valvetrain (EMV) actuators can replace the camshaft allowing for electronically controlled variable valve timing (VVT) on a new generation of engines. Before EMV actuators can be used in production vehicles two critical problems need to be resolved. First, impact velocities between the valve, valve seat, and the actuator itself need to be small to avoid excessive wear on the system and ensure acceptable levels of noise. Second, the opening and closing of the valve needs to be both fast and consistent to avoid collision with the piston and to reduce variability in trapped mass. This paper presents an observer based output feedback controller designed to achieve these goals. Theoretical analysis and experimental results of the controller are provided. The experimental results show a factor of six reduction in impact velocity and consistent and quick valve timing.