Control of Engine Load via Electromagnetic Valve Actuators

The purposes of this research were to demonstrate new electromagnetic valve actuators on a running engine and to explore the efficiency and emissions advantages of variable valve actuation. A single-cylinder research engine was equipped with programmable electromagnetic valve actuators and operated with early intake-valve closing in addition to conventional throttling, both methods with and without exhaust gas recirculation. The engine was run at a fixed speed of 1500 r/min over varying load at stoichiometric air-fuel mixture, with and without swirl generated by a shrouded intake valve. Engine performance and emissions were measured with spark timing adjusted to minimum advance for best torque. Early intake-valve closing showed a net-efficiency gain over conventional throttling without EGR, but essentially no gain over conventional throttling with heavy EGR dilution in the test engine. Electrical input energy for the actuators was less than the equivalent friction loss for a conventional non-roller valvetrain at this speed.