The German mechanical engineer Rudolf Diesel (1858-1913) is remembered for the compression-ignition internal combustion engine which bears his name.

Rudolf Diesel was born March 18, 1858, in Paris. His interest in mechanics was early roused by frequent visits to the Conservatoire des Arts et Métiers. Early in the Franco-Prussian War (1870) all Germans had to leave Paris, and the Diesels went to England in poverty. After a brief stay there, Rudolf went to an uncle in Augsburg, Germany, where he received a thorough scientific schooling. From 1875 he attended the Munich Polytechnikum (later the Technische Hochschule) and graduated with highest honors. He studied thermodynamics under Carl von Linde and resolved--given the opportunity--to design a heat engine with a thermodynamic cycle approximating to the ideal described by Sadi Carnot in 1824. Great fuel economy could be expected from such a machine. But the opportunity was a long time coming. Meanwhile, in 1880 he returned to Paris to assist in the construction of a refrigeration plant for Linde and then became manager of it. During this period (1881-1890) he put much effort into an abortive design for an expansion engine using ammonia as working fluid (ammonia was also the working fluid in the refrigerator). From Paris, Diesel moved to Berlin in 1890 and continued to work for Linde's refrigeration concern.

About 1890 Diesel saw that air could be used as the working fluid and worked out the elements of his engine cycle. Air, highly compressed in a cylinder, would rise in temperature; fuel injected into this hot gas would burn spontaneously. Ideally, combustion would occur at constant temperature and pressure, and expansion of the gases would drive the piston. Thus the conversion of heat to work would reach an optimum. Diesel's design was sufficiently advanced for him to patent it in 1892, and he described it in the paper "The Theory and Design of a Rational Heat Engine" (1893). With Linde's support two outstanding German concerns, Maschinenfabrik, Augsburg, and Friedrich Krupp, Essen, agreed to finance its development. From 1893 Diesel worked on the engine at Augsburg. By 1897 the engine was perfected to Diesel's satisfaction, and it was displayed in the Munich Exhibition of 1898. It used a heavier fuel oil than the then relatively explosive gasoline engines with which it was to compete. Its fuel economy was remarkable, and it ran quietly.

With success came worldwide interest, and manufactures were licensed to build the engine. In 1897 Adolphus Busch acquired the United States license for $1 million cash. In 1899 a new company was established in Augsburg to make the engine, but Diesel's illness and rife speculation in the shares made the venture a failure. However, development work forged ahead elsewhere. Illness, stemming from overwork in the development period, crippled Diesel, and thought he continued lecture tours, his direct involvement in the engine declined. He died at sea after falling from the Antwerp-Harwich steamer Dresden on the night of Sept. 29/30, 1913.

Further Reading

• The chapter on Diesel in Eugen Diesel and others, From Engines to Autos: Five Pioneers in Engine Development (1960), provides valuable information. A laudatory biography of Diesel, written in a journalistic style, is Robert W. Nitske and Charles Morrow Wilson, Rudolf Diesel: Pioneer of the Age of Power (1965).