Abstract: A family of embodiments of mechanical, electromechanical and electronic for the control of intake and exhaust cylinder valves applicable to both spark and compression ignition engines. Electronic control or programming of valves in respect to their opening and closing times is effected in accordance with predetermined relationships based on data such as air density, engine temperature, engine speed, vehicle speed, fuel octane, automatic transmission data and operator control commands and operating mode selections is provided. The operator control commands include acceleration and deceleration; and the operating mode selections include "computer starting" (without cranking as by a starter mechanism); and constant speed, constant torque, engine reversal, low nitrogen oxide emission, high performance, optimum fuel economy and service modes.

Abstract: An electro-hydraulic system capable of high speed and precision timing, is disclosed, particularly adapted to the opening and closing of the intake and exhaust valves of an internal combustion engine under computer control. The actuator is powered by pressurized crankcase oil which is discharged on the engine valve stems for lubrication. The system employs hydraulic cushioning to reduce engine valve seating velocity, and recovers energy on the return stroke of the valve to improve efficiency. High speed is achieved by rapid de-energization of electromagnets which hold the fluid control valves closed against the force of the pressure of the hydraulic supply. These electromagnets latch the valves in their most power-efficient mode, that is, with the magnetic circuit gap at or near zero.