1832-1891

German engineer who built the first four-stroke internal combustion engine. The principle of a four-stroke engine (intake, compression, combustion/power, exhaust) had been patented by the Alphonse Beau de Rochas several years earlier, but Otto's engine was the first to be constructed. The four-stroke engine ran more efficiently than previous types and helped make internal combustion engines lighter in weight and more powerful. This type of engine is still known as the Otto cycle.