Abstract: An internal combustion engine has a cylinder and a piston with rectangular cross sections. A guideway slot extends across one face of the piston, and engages an off-center pin affixed to the crankshaft for translating linear movement of the piston to rotational movement of the crankshaft. The cylinder may be formed of four side wall plates mounted to define the side walls of the cylinder, and plate means covering the ends of the side wall plates to define a combustion chamber and a crankcase. The crankshaft may be hollow, to define a fuel inlet passageway.

Abstract: A rotary piston engine has a pair of lobed rotors affixed to parallel axes for rotation in respective connected cylinders defined by a housing. Pressure compensating channels are provided in the walls of the housing at the intersections of the connected cylinders, where the lobes of the rotors engage and lift-off from their respective cylinders. A fuel injection inlet is provided in the precompression region of the engine.