Patent ID: 8117826

Claim:
An external combustion engine comprising: a first engine housing defining a first engine chamber, wherein said first engine chamber defines an interior surface and comprises a space for containing and directing expansive gas generated by combustion of a fuel; a combustion chamber coupled to said first engine housing such that expanding gas produced by said combustion of said fuel passes from said combustion chamber into said first engine housing through a combustion gas inlet; a driveshaft positioned within said first engine housing, said driveshaft extending from a center of said first engine housing and passing through a wall of said first engine housing for coupling said external combustion engine to devices; wherein said driveshaft rotates about a driveshaft axis passing lengthwise through a center of said driveshaft; a first rotatable piston positioned within said first engine housing, said first rotatable piston including a first piston riser extending fixedly from said first rotatable piston to abut said interior surface of said first engine chamber, said first rotatable piston being coupled to said driveshaft and configured to rotate about said driveshaft axis when expansive gas resulting from said combustion of said fuel contacts said first piston riser of said first rotatable piston; a first backstop valve extending into said first engine chamber and coupled to said first engine housing such that said first backstop valve directs expansive gas resulting from said combustion of said fuel toward said first rotatable piston; wherein said first piston riser contacts said first backstop valve to close said combustion gas inlet; wherein said first engine housing further defines a first exhaust outlet configured to exhaust used expansive gas resulting from said combustion of said fuel; and ignition and timing controls coupled to said first engine housing and configured to combust said fuel.