Nicolaus Otto, born in Holzhausen, Germany in 1832, is known for designing the first gas-powered internal combustion engine. Much of the ground work behind the internal combustion engine, such as control volumes and multiple part mechanisms, had been used in steam engines of the era. With new understanding of thermodynamics and chemistry brought out in the early 1800's, Otto was the first engineer to incorporate them all to one model. His multidisciplinary approach to the pre-existing two-stroke engine led him to determine that there are truly 4 different strokes that an engine could use to extract power throughout a cycle. The development of the four-stroke combustion cycle, the Otto Cycle, was a major breakthrough for modern engineering and paved the way for the ensuing industrial revolution.
Otto's interest in developing a four-stroke engine was inspired by Etienne Lenior's two-stroke internal combustion engine. He began experimenting with the new technologies of the 1860's and eventually came to meet Eugen Langen. They were both very interested by the four-stroke engine concept. With Langen as a partner, Otto quit his job to start N.A. Otto and Cie engine manufacturing company in 1864. Then in 1876, Otto built the first practical four-stroke engine, the Otto Engine. He was awarded a patent for the gas-motor engine in 1877, along with Francis and William Crossley. He built on this concept eventually adding the first magneto ignition system in 1884. With his work complete, he applied for a patent in 1886. His application was overturned and the patent granted to Alphonse Beau de Roaches who had designed a four-stroke engine but had never built one. There has since been much scrutiny about exactly who built what, though most settle on individual contributions to the engine as a whole. Nicolaus Otto died at 59 in 1891 at his home in Cologne.
Four-stroke engine animation: