This is intended as an example of how much power can be produced out of nothing but heat and air density, and how your car's engine has to overcome this.
Stirling's air engine (as it is referred to in early text books - see hot air engine history) was invented by Reverend Dr Robert Stirling and patented by him in 1816. When the name became simplified to Stirling engine is not known, but may be as recently as the mid twentieth century when the Philips company began to experiment with working fluids other than air - the instruction book for their MP1002CA (see below) still refers to it as an 'air engine'. The main subject of that original patent was a heat exchanger which Stirling called the "economiser" for its enhancement of fuel economy in a variety of applications. The patent also described in detail the employment of one form of the economiser in an air engine, in which application ...