Sliding-valve in a heating-chamber combustion engine

Claim 1

An open air cycle engine comprising: (a) a cylinder; (b) a piston slideably engaged within said piston; (c) a cylindrical insert at the upper portion of the cylinder with a fluid passage provided therein; (d) a heating chamber located in close proximity with the outer sidewalls of the cyliner; (e) an air passageway in the cylinder sidewall providing communication with the heating chamber and the space within the cylinder, said passageway being located at a position approximately adjacent the top dead center of the piston's travel; (f) a valve element mounted on the piston extending vertically upwards and in sliding contact with the inner cylinder wall, whereby the air passageway is closed by the valve element during substantially all of the piston travel; (g) an opening in the valve element allowing communication between the air passageway and said chamber when said opening is aligned with the air passageway, said valve opening being in alignment with the air passageway only when the piston is approximately at it's top dead center of travel; (h) conduit means from the heating chamber to the fluid passageway in said cylindrical insert; (i) said fluid passageway extending into contact with the sliding valve element, whereby heated air from the heating chamber flows through the conduit to said fluid passageway to provide a pressurized fluid biasing the sliding valve element into close contact with the cylinder wall; (j) further valve means for exhausting air from the cylinder after the piston has completed its working stroke.