Abstract: The internal combustion engine includes a working cylinder, a compressed air supply, an injector for supplying a gas and fuel mixture, an exhaust valve and an inlet valve. The inlet valve delivers both gas under pressure and gas and fuel mixture to the working cylinder, commencing delivery of the gas under pressure at an earlier stage in the engine cycle to the commencement of delivery of gas and fuel mixture. The inlet valve delivers gas under pressure to the cylinder at least for a part of the time that the exhaust port is open so as to drive combusted gases out of the working cylinder. The internal combustion engine also includes a rotary valve having a first member of a cylindrical external configuration, a sleeve surrounding the first member, and a mechanism for rotating the sleeve relative to the first member. The first member comprises a plurality of fluid passages and a plurality of apertures allowing communication of each of the passages with the exterior of the first member.

Abstract: The present invention includes an internal combustion engine having at least one piston reciprocating within a cylinder, and an exhaust port allowing communication of the cylinder with an exhaust passage. A moveable shutter is provided to vary the effective area of the exhaust port. The shutter varies the effective area cyclically in a timed relationship to the reciprocal motion of the piston within the cylinder. A sensor is provided to measure an operating characteristic of the engine and to generate signals responding to the operating characteristic sensed. A control unit is provided to process the signals and to control the motion of the shutter in response to the signals.