Felice Matteucci
According to recent historical studies, the Italian inventors Eugenio Barsanti and Felice Matteucci patented a first working efficient version of an internal combustion engine in 1854 in London (pt. Num. 1072). It is claimed that the Otto engine is in many parts at least inspired from this precedent invention, but, as yet there is no documentation of knowledge about the Italian engine by Otto.