Étienne Lenoir, Belgian engineer, designed the internal combustion engine (died 1900)

Jean Joseph Étienne Lenoir, also known as Jean J. Lenoir, was a Belgian-French engineer who invented the internal combustion engine in 1858. Prior designs for such engines were patented as early as 1807 and 1854.

An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance. This process transforms chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.