US Patent 7721686 Method and system for controlling a free-piston energy converter

A method and system for controlling a free-piston energy converter is disclosed in which effects of events, like combustion events, in at least one of at least two cylinders, are decoupled from each other by predicting forces acting on the moving mass of the converter during a stroke of the moving mass and by evaluating or estimating a value representing a force which is exerted onto the moving mass, so that the moving mass reaches a desired reference condition or state, like a desired reference kinetic energy, at a certain position along the stroke.