Patent ID: 7726268

Claim:
An internal combustion engine comprising: at least three cylinders each having a reciprocating piston moveable between a top dead center position and low dead center position in relation to a single variable volume combustion chamber defined between a head of the piston and a top of the cylinder; the reciprocating piston in each of the cylinders being operable through a six stroke cycle including an intake stroke, a compression stroke, a power stroke, an exhaust stroke and two free strokes defined by reciprocating downward and upward movement of the piston during which there is no intake stroke, compression stroke or power stroke taking place within the cylinder; an intake port on the top of the each of the cylinders for allowing injection of a fuel and air mixture into the single combustion chamber; an intake valve operatively associated with each intake port and operable between an open position during the intake stroke to allow injection of the fuel and air mixture, and a closed position prior to the compression stroke in order to seal the intake port closed; an exhaust port on the top of the each of the cylinders for allowing release of gases from combustion of the fuel and air mixture in the single combustion chamber; an exhaust valve operatively associated with each exhaust port and operable between a closed position to seal the exhaust port closed and an open position throughout the exhaust stroke; a clean air port and valve assembly operable from a closed position to an open position during the two free strokes; and the piston in any one of the cylinders being structured and disposed for operating through the power stroke while another of the pistons in another of the cylinders simultaneously operates through one of the free strokes.