Nicolaus August Otto (10 June 1832 – 26 January 1891) was a German engineer who successfully developed the compressed charge internal combustion engine which ran on petroleum gas and led to the modern internal combustion engine. The Association of German Engineers (VDI) created DIN standard 1940 which says "Otto Engine: internal combustion engine in which the ignition of the compressed fuel-air mixture is initiated by a timed spark", which has been applied to all engines of this type since.
Provided by Wikipedia