Harry Schoell, a marine designer in Pompano Beach, FL, and inventor of the Cyclone engine (www.cyclonepower.com) describes his new engine design this way: “It’s not dirty. It’s very clean. It gets washed frequently.” That’s because the Cyclone is a Rankine-cycle engine, which means it is related to a steam engine, and uses a continuous cycle of liquid vaporization and condensation in a sealed container to create power. Though Rankine-cycle engines have been designed for experimental use in automobiles, mostly to reduce pollution, they never made a mark in the automobile industry due to the problems associated with lubricating an external combustion engine without having the water and oil mix. Those worries may be over. The Cyclone doesn’t use oil for lubrication.
“In the marine industry,” says Schoell, “we use a lot of water-lubricated parts. A water bearing, done properly, is quite slippery.” What these bearings have not been, until recently, is capable of operating for any length of time in a steam environment. Specially formulated PEEK (poly-ether-ether-ketone) bearings capable of standing up to high temperature super-critical steam are used in the Cyclone. “With the primary heat exchange system running at 1,200ºF,” says Schoell, “the steam density would have been too low for the heat exchanger to be efficient.” Increasing the pressure of the steam to 3,200 lb/in2 took care of this problem by making it act like a liquid and not a gas.
The primary components of the engine include a condenser, steam generator and the requisite valves, cylinders, pistons, pushrods, main bearing, cams, and camshaft. Ambient air enters the engine through the intake blower, which circulates it through the condenser. According to Schoell, the flat-plate condenser “looks like a set of stacked record albums where air goes around the outside of the discs while the vapor on the inside is spun.” It is then directed through heat exchangers, and the air is pre-heated, enters the steam generator, and is mixed with atomized fuel that is also spun in the centrifuge. Schoell claims this “causes the heavy elements to stay to the outer wall until they are burned up, much like in a self-cleaning oven.” He also says the fuel spray runs only when the engine needs to replenish the heat contained in the super-critical steam. At stoplights, the engine would run on residual heat in the system.
The power output is controlled by a rocker arm and cam design that opens and closes a needle valve in the head. This introduces high-pressure, high-temperature steam into the cylinder and provides the expansion force necessary to drive the pistons. Because it relies on the expansion of the fluid and not the expansive capacity of the fuel to create power, the Cyclone engine is fuel independent. It can run on almost any liquid or gaseous fuel. “We should do a better job on hydrogen than an internal combustion engine,” says Schoell, “because it has a lot of heat (BTUs), but not a lot of expansion.”
As Schoell describes it, the preferred thing would be for a large manufacturer to buy the rights to the engine and develop it further. While he waits for that to happen, development continues apace, with a licensing agreement in place to develop the smaller version for an electric generator set. It may take years for the 38-in.3, 330-lb, radially-opposed six-cylinder Mark V version to use its 700 lb-ft of starting torque, 100 hp, and 134 lb-ft @ 3,600 rpm to power a car or truck, but Schoell isn’t worried. He’s been at this for 30 years.