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Why is the four-stroke cycle also called the Otto cycle?

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Labeled cross-sectional diagram of a V-type gasoline engine for an automobile, showing internal components such as pistons, crankshaft, camshaft, intake and exhaust valves, connecting rods, spark plugs, and intake manifold. — gasoline engine Cross section of a V-type engine.

The four-stroke cycle is commonly called the Otto cycle because the German engineer Nikolaus August Otto was the first to successfully build and market an engine based on this principle in 1876.123

Although the French engineer Alphonse Beau de Rochas had patented the theoretical four-stroke cycle in 1862, he never constructed an engine using it. Because Otto’s design was the first practical application to achieve widespread success, the term "Otto cycle" became the standard designation for the process. It is important to note that while Otto’s patent was later revoked in 1886 after the earlier work of Beau de Rochas was brought to light, the name remains in common use to describe the four-stroke cycle used in most modern gasoline engines.1234