Otto gas engine. Historical illustration of various sections through a horizontal Otto gas engine. A gas engine is an internal combustion engine that runs on a gas fuel, such as natural gas, instead of the petrol used in car engines. Gas engines are usually used in heavy-duty industrial settings, such as factories. The first practical gas engines were developed in the 1860s, including those by German engineer Nikolaus Otto (1832-1891) in 1862 and 1867. Artwork from 'Moteurs' (1911) by French civil engineer Max de Nansouty (1854-1913), part of the 'Les merveilles de la science' series of 1867-1891 by Louis Figuier.