Trajectory generation for camless internal combustion engine valve control

Camless internal combustion engines offer major improvements over traditional engines in terms of efficiency, maximum torque and power, pollutant emissions. Electromechanical valve actuators are very promising in this context, but still present significant control problems. Low valve seating velocity, small transition time for valve opening and closing, unavailability of position sensor are the main objectives to be considered in the design of the valve control system. Actuator physical limitations strongly influence the feasible trajectory when low valve seating velocity is required, thus affecting valve transition time. One key point for the control is the design of the reference trajectory to be tracked by the closed loop controller. In this paper, the trajectory design is addressed, solving an optimization parametric problem that explicitly considers the physical constraints and the trade-off between fast dynamic performance and system robustness.