User:Accesschris

A Schoell cycle engine is a heat regenerative, external combustion engine that uses water as both the working fluid and lubricant. It uses a thermodynamic cycle known as a Rankine Cycle to create mechanical power in a closed loop system. The engine is named after Harry Schoell, its inventor.

The Schoell Cycle Engine is a modern day, advanced steam engine that combines the elements of steam generation, water condensing and engine mechanics (pistons, cams, shaft, etc.) into one compact unit. It achieves thermodynamic efficiencies through its multiple processes of heat regeneration, in essence harvesting lost heat from the engine operation and exhaust, to preheat combustion air and super heat the working fluid.

Background
Steam engines...

Operation
A Schoell Cycle Engine is a compact, efficient external combustion engine which uses water as the working fluid, as well as the lubricant. The engine consists primarily of a condenser, a steam generator and a main engine section having valves, cylinders, pistons, pushrods, a main bearing, cams and a camshaft.

Ambient air is introduced into the condenser by intake blowers. The air temperature is increased in two phases (known as heat regeneration) before entering a cyclonic furnace. In the first phase, air enters the condenser from the blowers. In the next phase, the air is directed from the condenser and through heat exchangers where the air is heated prior to entering the steam generator.

In the steam generator, the preheated air is mixed with fuel from a fuel atomizer. The burner burns the fuel atomized in a centrifuge, causing the heavy fuel elements to move towards the outer sides of the furnace where they are consumed. The hotter, lighter gasses move through a small tube bundle.

The cylinders of the engine are arranged in a radial configuration with the cylinder heads and valves extending into the cyclonic furnace. Temperatures in the tube bundle are maintained at temperatures up to 1,200 degrees Fahrenheit. The tube bundle, carrying the steam, is directed through the furnace and exposed to the high temperatures. In the furnace, the steam is super heated and maintained at a pressure up to approximately 3,200 lbs.

Exhaust steam is directed through a primary coil which also serves to preheat the water in the generator. The exhaust steam is then directed through a condenser, in a centrifugal system of compressive condensation, consisting of a stacked arrangement of flat plates. Cooling air circulates through the flat plates, is heated in an exhaust heat exchanger and exits into the furnace. This reheat cycle of air greatly adds to the efficiency and compactness of the engine.

The speed and torque of the engine are controlled by a rocker and cam design which serves to open and close a needle type valve in the engine head. When the valve is opened, high pressure, high temperature steam is injected into the cylinder and allowed to expand as an explosion on the top of the piston high pressure. Use of three or more pistons allows for self-starting.

Applications
Schoell Cycle Engines are currently in development, however, stated applications range from small garden equiment like lawn mowers and weed wackers to electric power generators, automobiles, trucks, ships and locomotives.