Nicolaus Augusto Otto

Nikolaus Otto (1832-1891), German inventor, who devised the Otto cycle engine—the first effective four-stroke internal-combustion engine.

Nikolaus August Otto was born in Holzhausen, Germany. He left school at age 16 and moved to Cologne. After seeing the coal-gas engine designed and built by French inventor Jean-Joseph-Étienne Lenoir in 1859, Otto began experimenting with internal-combustion engines. He built his first engine based on Lenoir’s design in 1861. He joined forces with German industrialist Eugen Langen in 1864 to form a company near Cologne, and the firm turned out its first production-model engine in 1867.

The first engine produced by Otto’s firm was a two-stroke engine that drew in a fresh air-fuel mixture on the same stroke it exhausted the spent mixture of the previous cycle. It was much more efficient than Lenoir’s engine because the two-stroke engine compressed the gas before igniting it. In 1876 Otto and Langen announced a newer, much more efficient four-stroke engine. In this engine the air-fuel mixture was drawn in on one stroke of the piston and then compressed and ignited on the next. The third stroke of the piston transferred the power of the exploding gases to the engine’s crankshaft, and the fourth stroke of the piston was used to expel, or exhaust, the spent gases. The new engine, which was quiet and efficient, was named the Otto cycle engine. It caught on at once and remains the basic design of most modern internal-combustion engines.

Otto patented the Otto cycle in 1877 and formed a company that in a few years sold 35,000 engines, primarily for use in small factories. In 1886, however, Otto’s competitors showed that French engineer Alphonse-Eugène Beau de Rochas had suggested the principle of the four-stroke engine in an obscure pamphlet before Otto developed his cycle engine. Although this invalidated Otto’s patent, the Otto engines were still the only internal-combustion engines widely used. In 1890 Wilhelm Maybach and Gottlieb Daimler, two of the lead engineers in Otto’s firm, launched their own firm to produce automobiles powered by Otto cycle engines. They refined the Otto cycle engine and went on to manufacture the first Mercedes automobile in 1899.