Abstract: A two stroke internal combustion engine with piston and cylinder has a crankshaft having peripheral gears and a cam both affixed to the same crankshaft throw. A trough is in the engine crankcase whereby the gears pass through lubrication.

Abstract: An engine driven reciprocating air compressor. The engine is operated in a through scavenge two-stroke mode. The engine has opposed pistons reciprocating in opposition in a cylinder, the pistons being rigidly connected to respective compressor pistons working in compressor cylinders. A crankshaft rotates about an axis perpendicular to and intersecting the engine cylinder axis. The piston pairs are directly coupled to the crankshaft by connecting rods. The crankshaft synchronizes the piston pairs, defines their strokes, and provides rotary motion for auxiliary devices. The connecting rods and crankshaft are lightweight and do not transmit full engine power. The piston pairs are provided with inward return energy from a flywheel on the crankshaft and air trapped in compressor cylinder clearance volumes. The inward faces of the compressor pistons may be used to compress fuel/air mixture to the scavenge pressure.