The Minto Engine

This Steam Automobile article from 1972 discusses Wally Minto's engine. The Minto engine is a modern day (1970s) version of the steam engine of the early 1900s. Based on the rankine cycle, it primarily consists of a fuel burner, heat exchanger, drive motor and a condenser. It operates similar to the traditional steam engine of the past except that it uses freon (or similar) as a working fluid rather than water/steam. In addition, the system operates in a "closed loop" so that the working fluid never needs to be replenished. The drive motor is a cross between a piston engine and a turbine and it can provide full torque regardless of engine speed. Because it is an external combustion engine, its exhaust is virtually pollution free as it contains none of the combustion products inherently created by an internal combustion engine. Plus, being an external combustion engine, it isn't limited to using gasoline--it can use virtually any type of fuel. When at a dead stop, the engine doesn't need to turn over as it can produce maximum torque from a stand-still. The engine requires no transmission, differential, clutch, ignition system, muffler, engine oil... It can produce as much power as a modern internal combustion engine but because of its superior torque characteristics as well as fewer drive train components, it doesn't require as much power. Acceleration is smooth as there is no need for shifting gears. Fuel economy is comparable to that of an internal combustion engine.

PDF file location: https://archive.org/details/the-minto-engine