Which inventor developed the first widely used diesel engine, patented in 1892?

Rudolf Diesel developed the first widely used diesel engine and patented his engine concept in 1892.

Diesel sought a more efficient heat engine than the steam engines and petrol engines of his era. His design compressed air until it became hot enough to ignite fuel injected into the cylinder. Unlike a petrol engine, it did not require a spark plug for ignition.

Diesel received German patent DRP 67207 on February 23, 1893, building on an earlier patent application from 1892. The first successful engine was tested by Maschinenfabrik Augsburg, later part of MAN, in 1897. It achieved considerably higher efficiency than many contemporary engines.

The diesel engine is named after its developer, not after the fuel alone. Diesel engines can use several fuels, while modern diesel fuel is a petroleum-based product. The technology became important in ships, locomotives, trucks, generators, and industrial machinery because of its efficiency and strong low-speed torque.