Abstract: The invention involves a variable valve timing actuator that allows the opening and closing of engine valves to be variably and individually controlled without using a camshaft. The invention utilizes energy regeneration so energy delivered to a valve while accelerating it is recovered while it is decelerating. Regeneration is preferably provided by potential energy storage devices such as springs. Energy losses are made up by adding energy to the actuator while the valve is stationary (or nearly so) in an open or closed state. This is done by (1) moving the spring seats in relation to the valve, thereby “charging” the springs in relation to the valve, and/or by (2) moving the valve with respect to the spring seats to “charge” the springs with respect to the valve. This energy addition is extremely efficient because it is performed after the potential energy within the springs has already been expended and the valve is sitting stationary in its open and closed positions.