Patent ID: 6986329
Filing Date: 2006-01-17
Classification: F02B

Abstract:
1. An engine comprising: a crankshaft having a crank throw, the crankshaft rotating about a crankshaft axis; a compression piston slidably received within a compression cylinder and operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke of a four stroke cycle during a single rotation of the crankshaft; an expansion piston slidably received within an expansion cylinder; a connecting rod pivotally connected to the expansion piston; a mechanical linkage rotationally connecting the crank throw to the connecting rod about a connecting rod/crank throw axis such that the expansion piston reciprocates through an expansion stroke and an exhaust stroke of the four stroke cycle during the same rotation of the crankshaft; and a non-circular path established by the mechanical linkage which the connecting rod/crank throw axis travels around the crankshaft axis, the distance between the connecting rod/crank throw axis and crankshaft axis at any point in the path defining an effective crank throw radius, the path including a first transition region from a first effective crank throw radius to a second effective crank throw radius through which the connecting rod/crank throw axis passes during at least a portion of a combustion event in the expansion cylinder.