Patent ID: 8109097

Claim:
A combined cycle engine comprising at least one cylinder having a combustion piston slideably mounted therein between a combustion chamber and a steam expansion chamber wherein the combustion chamber is outward of the piston and the steam expansion chamber is located inside the piston between the piston and a fixed cylinder cap that is slideably and sealingly mounted inside the piston, a steam supply heated by waste combustion heat is connected to power the engine by supplying steam to the steam expansion chamber through a pair of separate and independently movable inwardly retractable steam inlet valves located inside the piston and connected in communication with one another and with the steam expansion chamber through the cylinder cap, a valve retractor connected to open each of the steam inlet valves proximally, and a steam exhaust valve that opens to communicate with the steam expansion chamber for exhausting steam from the steam expansion chamber when the piston is in an expanded state and is closed during at least a portion of a power stroke thereof.