Experiments with a Malone engine

A complete four-cylinder experimental Malone (Stirling-cycle) engine has been built. It uses liquid propylene (C₃H₆ ) as its working substance. Extensive measurements made with the propylene engine are reported and compared to the predictions of a theoretical model. The predictions are in good agreement with the engine´s observed performance. The test engine is very versatile. It can operate as a prime mover or as a heat pump, and crankshaft speed, piston displacement, static and dynamic pressure, and temperatures can be varied while the shaft power and heat flow are measured. The engine operates near room temperature with temperature differences up to about 30°C, frequencies up to 5 Hz, heat flows up to 1000 W, and shaft power up to 300 W