more jets in the air. The efficiency of combustion engines has been rising fast since James Watt launched the industrial age 250 years ago. The best external combustion engines were about 20% ...

The Stirling engine concept, named after Scottish inventor Robert Stirling who introduced his model in 1816, is sometimes called an external combustion engine because heat is applied from outside ...

The steam engine is another example of an external combustion engine. In order to create a microscopic version of a Stirling engine, the researchers sandwiched a tiny, 2.94 μm melamine bead in a ...