Stirling engine mechanism,artwork. This heat engine operates by the cyclic compression and expansion (black arrows) of a working fluid (typically air). The air is shunted between cylinders at different temperatures,which creates a net conversion to mechanical work. This sequence,from top to bottom,shows: entry of air into a hot expansion cylinder (red,top),followed by compression (centre) into a cold cylinder (blue),followed by compression of the cold cylinder,leading to heating of the air (red arrow,bottom) as it exits the cold cylinder. The cycle then repeats. Developed in 1816,this engine and mechanism is named for its Scottish inventor Robert Stirling |