Modeling and control of automotive gas exchange valve solenoid actuators

A promising method for enhancing automotive internal combustion engine efficiency uses solenoid actuators to directly control the gas exchange valves. Mitigation of valve seating velocities is challenging due to phenomena such as magnetic saturation and combustion gas force disturbances. A comprehensive control strategy is presented for a hinged solenoid actuator. Gas forces on the exhaust valve are particularly problematic due to the potential for large cycle-to-cycle variations. Soft seating is achieved using a flatness-based landing algorithm with a nonlinear disturbance estimator. The estimator is used with an energy-based feedforward controller to reject exhaust gas force disturbances. Feedback is provided through the use of flux and current measurements and an accurate inductance model. Overviews of the employed modeling and simulation techniques and experimental testbench results are also presented. Both simulated and experimental results indicate the proposed control methodology is capable of compensating for the nonlinear magnetic dynamics and combustion gas force disturbances experienced by exhaust valve solenoid actuators.