U.S. Military Looks Into Clean-burning Cyclone Engine

Schoell, a Florida inventor, envisions a day when his external combustion engine replaces most of today's gasoline- and diesel-powered internal combustion engines. The U.S. Army and U.S. Navy think it may be an efficient way to generate electricity.

The Cyclone engine works by pumping fuel and air into a round combustion chamber, where it swirls cyclonelike and burns at about 2,000 degrees Fahrenheit. Combustion gas passes into a heat exchanger, where it heats deion-ized water to 1,200 degrees under 3,200 pounds of pressure.The water turns into steam, but under pressure the steam remains in a fluid state and is referred to as a "supercritical fluid,".

The steam passes through a valve and into a cylinder, where it expands with almost explosive force to drive a piston. When the piston is pushed to the far end of the cylinder, the steam exits through an exhaust port.From there, the steam enters another heat exchanger, where heat is recovered and cycled back to the combustion chamber. Now cooler, the steam exits the heat exchanger and enters an air-cooled condenser, where it is turned back into water and is pumped back to the first heat exchanger to go through the cycle again.

Schoell has run his engines on gasoline and diesel fuel, but also on fuel made from orange peels, palm oil and chicken fat.cyclonelike swirl of fuel and air in the combustion chamber enables complete combustion so there is little except carbon dioxide as exhaust.In February, Cyclone Power Technologies announced the completion of tests with Raytheon of a Cyclone engine designed for the Navy to use in unmanned underwater vehicles and torpedoes.

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