Rudolf Diesel invented the engine that bears his name, a design that ignites a variety of fuels, which spontaneously combust when introduced into the cylinder to meet the intense heat generated by air pressure. The high compression ratio of the diesel engine allowed for the burning of low-grade fuels, which was incredibly efficient and economical, but also highly pollutant, as these less-refined fuels burned with impurities, such as nitric oxide, and produced copious soot. Diesel died before the applications for his innovation became more universal: submarines in World War I used diesel engines almost exclusively, and the diesel locomotive overtook the steam engine as the primary source of power in the railroad industry after World War II.
Rudolf Christian Karl Diesel was born on March 18, 1858, in Paris of Bavarian parents. After the Battle of Sedan during the Franco-Prussian War in 1870, Diesel’s family was expelled to England, where they lived in poverty. Diesel went to live with an uncle in his father’s native town of Augsburg, Germany, where he attended secondary school. In 1875, he enrolled in the Technische Hochschule in Munich, where he studied thermodynamics under Carl von Linde.
Upon his graduation in 1880, Diesel moved back to Paris, where Linde had secured him a job in his building-refrigeration plant. Within a year, Diesel was promoted to plant manager. In 1885, Diesel set up his own laboratory to design and test an expansion engine fueled by ammonia, as an alternative to the huge, expensive, and inefficient steam engine that powered most industrial applications at the time. Although this particular design proved unsuccessful, it paved the way for his later innovation of the engine named after him.
In 1890, Linde’s company transferred Diesel to Berlin. At that same time, Diesel conceived of a new engine design, which he patented in 1892. The next year, he published a paper entitled "Theorie und Konstruktion eines rationellen Ware-motors" ("Theory and Construction of a Rational Heat Motor") describing his innovation: theoretically, the four-stroke engine could burn any fuel, ignited not by a spark but by the intense temperature (about 1,000 degrees Fahrenheit) attained by compressing air to a high pressure (about 500 pounds-per-square-inch) before the fuel was sprayed into the cylinder, thus expanding the gases (thereby avoiding the sudden pressure increase inherent in the internal combustion engine).
Diesel obtained financial backing from the Augsburg Maschinenfabrik, and from Baron Friedrich von Krupp of Essen, and set about building a prototype—a single 10-foot iron cylinder with a flywheel at its base. He conducted his first trial in Augsburg on August 10, 1893, which was a success, but it took several more years of improvements before his engine was commercially viable.
Part of the problem for these delays stemmed from his use of coal dust as fuel. A byproduct of the Saar coal mines in the Ruhr valley, coal dust was not only cheap and plentiful, but also it dovetailed with one of the philosophical underpinnings of Diesel’s engine: adaptability, so that individual craftsmen and artisans could use whatever fuels were locally available to power the engine, thus counteracting the de facto monopoly large corporations enjoyed due to the overbearing expense of operating expensive, inefficient engines in manufacturing. However, controlling the rate of introducing the coal powder into the cylinder proved difficult, and after one of his coal-dust-burning prototypes exploded, nearly killing its inventor, Diesel abandoned coal dust in favor of refined mineral oil and later heavy petroleum oils as fuel.
In 1897, an independent trial of the 25-horsepower engine, conducted by Professor M. Schroter, confirmed its incredible mechanical efficiency (75.6 percent efficient, in theory). Diesel displayed the engine at the Munich Exhibition of 1898, where the brewer Adolphus Busch witnessed it in action, prompting him to install the first commercial engine built on the Diesel patent in his St. Louis, Missouri, brewery. Duly impressed, Busch purchased the U.S. and Canadian licenses for manufacture and sales.
Diesel licensed his design worldwide. The industrialist and inventor alfred bernhard nobel, for example, manufactured diesel engines in his St. Petersburg plant and became a millionaire on royalties. He established his own factory in Augsburg in 1899.
Diesel died mysteriously at sea during an overnight crossing of the English Channel. It was generally presumed that he fell overboard from the mail steamer Dresden on September 29 or 30, 1913, while it was traveling between Antwerp and Harwich, but some historians believe he may have committed suicide. Throughout his life, Diesel had restricted licensing to abide strictly to his 1893 patent stipulating combustion at nearly constant pressure, which required operation at low speeds, thereby limiting the application to large engines (and hence preventing the innovation of smaller, more utile engines).
After Diesel’s death, however, more utilitarian applications were innovated, and the benefits of the diesel engine design were more fully exploited. Diesel engines, such as the Busch-Sulzer, and the Nelesco, built by the New London Ship and Engine Company of Groton, Connecticut, served as the primary technology powering submarines serving in World War I and continued to serve an important role in the nautical industry. Diesel technology subsequently became extremely important in the development of the railroad industry and, to a lesser extent, the automobile industry.
