US Patent 7469664 Internal combustion engine

An internal combustion engine is disclosed having opposed cylinders, each cylinder having a pair of opposed pistons. All the pistons may be connected to a common central crankshaft. The inboard pistons of each cylinder may be connected to a common joint on the crankshaft with pushrods and the outboard pistons may be connected to a common joint on the crankshaft with pullrods. Each opposed cylinder may include an integrated scavenge pump for providing positive intake pressure. The engine configuration also allows for asymmetrical timing of the intake and exhaust ports through angular positioning of the journals on the crankshaft.