Patent ID: 7810459
Filing Date: 2010-10-12
Classification: F02B

Abstract:
1. An engine comprising: a crankshaft, rotating about a crankshaft axis of the engine; an expansion piston slidably received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston is operable to reciprocate through an expansion stroke and an exhaust stroke of a four stroke cycle during a single rotation of the crankshaft and such that the ratio of the volume in the expansion cylinder when the expansion piston is at expansion piston's bottom dead center (BDC) position to the volume in the expansion cylinder when the expansion piston is at the expansion piston's top dead center (TDC) position is 26 to 1 or greater; and a compression piston slidably received within a compression cylinder and operatively connected to the crankshaft such that the compression piston is operable to reciprocate through an intake stroke and a compression stroke of a four stroke cycle during a single rotation of the crankshaft; wherein the engine is operable to initiate combustion in the expansion cylinder while the expansion piston is descending from the expansion piston's TDC position towards the expansion piston's BDC position.