Patent ID: 7552703

Claim:
An internal combustion engine, comprising: a combustion chamber, a fuel inlet for providing fuel to be burned in the combustion chamber, at least one expansion cylinder, a piston in each expansion cylinder, a crankshaft constraining each piston for reciprocating movement between top and bottom dead center positions in each expansion cylinder, an inlet valve for controlling communication between the combustion chamber and each expansion cylinder, and an exhaust valve for controlling exhaust flow from each expansion cylinder, wherein each inlet valve is configured to remain open during at least a portion of the downstroke of the piston in each expansion cylinder and to close when the volume of air at atmospheric pressure taken into the engine times the expansion at full load is equal to the total volume of all of the expansion cylinders when each piston is at its bottom dead center position, and each exhaust valve is configured to open when the pressure in the expansion cylinder associated therewith is at or near atmospheric pressure.