Patent ID: 7140182

Claim:
A method of operating an internal combustion engine, said engine comprising a multi-stage-intercooled compressor, a power transfer means for driving said compressor, a power output shaft for attaching a load, and one or more energy-storing expanders, each energy-storing expander comprising a) an energy storage chamber; b) a movable wall inside said energy storage chamber with a space above said movable wall open to compressed air from said compressor; c) an inlet valve to allow compressed air into the space below said movable wall, d) a spring to move said movable wall away from said inlet valve when said inlet valve is open and the pressures above and below said movable wall are equal; e) a heating means for increasing the heat in said energy storage chamber; f) a cylinder, with said energy storage chamber at one end; g) a power piston in said cylinder, which moves in a reciprocating manner; h) a pusher piston in said cylinder which moves in a reciprocating manner and transfers pressure forces on said power piston to said power output shaft; i) a cam on said power output shaft and a push rod to move said power piston near the energy storage chamber end of said cylinder and keep said power piston there until said pusher piston moves to the top of said pusher piston's stroke in said cylinder; j) an exit valve; said method of operating said internal combustion engine comprising the steps of: compressing air at near constant temperature, compressing air at near adiabatic conditions, storing energy in said energy storage chamber, heating said compressed air at near constant volume, expanding the heated compressed air at near adiabatic conditions, using the stored energy of said energy storage chamber, expanding said heated compressed air at near adiabatic conditions, and adjusting said exit valve rejecting said heat to ambient.