Abstract: An internal combustion engine having at least one and preferably two cylinders each with a reciprocating piston, and a compressor which has a reciprocating piston driven by the engine to compress a rich fuel and air mixture within the compressor to inject the mixture directly into the combustion chamber of each engine cylinder. The mixture is ignited by a spark plug to drive the pistons of the engine through their power strokes and rotate an associated crankshaft which is connected to a compressor crankshaft to reciprocate the piston within the compressor and thereby compress and then inject the fuel and air mixture into the engine cylinder. A carburetor preferably supplies an enriched fuel and air mixture to the compressor to reduce the complexity of the system. The fuel and air mixture is preferably substantially atomized through nozzles adjacent each cylinder to improve combustion of the mixture.