US Patent 7341041 Toroidal engine with variable displacement volume

A novel rotary engine of the kind having a toroidal cylinder and a set of pistons on a rotating circular piston assembly provides instantaneous adjustment of the displacement volume of the engine by varying the intake and expansion stroke length on the circular path of the pistons through the opening and closing of valves into the engine cylinder under the control of an engine management system responsive to the speed/load conditions of the engine and the throttle position.