Rudolf Diesel

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Lore & Background

Rudolf Diesel was born on 18 March 1858 at 38 Rue Notre-Dame-de-Nazareth in Paris, France, the second of three children of Elise and Theodor Diesel. His parents were Bavarian immigrants. Shortly after birth, Diesel was given away to a Vincennes farmer family, where he spent his first nine months. When returned, the family moved into a flat at 49 Rue de la Fontaine-au-Roi. The Diesel family suffered from financial difficulties, so young Rudolf had to work in his father's workshop and deliver leather goods using a barrow. He attended a Protestant-French school and soon became interested in social questions and technology. Being a very good student, 12-year-old Diesel received the Société pour l'Instruction Elémentaire bronze medal and had plans to enter Ecole Primaire Supérieure in 1870. At the outbreak of the Franco-Prussian War, his family was deported to England, settling in London, where Diesel attended an English-speaking school. Before the war's end, his mother sent 12-year-old Rudolf to Augsburg to live with his aunt and uncle, Barbara and Christoph Barnickel, to become fluent in German and to visit the Königliche Kreis-Gewerbeschule, where his uncle taught mathematics. He was enrolled at the Technische Hochschule. At age 14, Diesel wrote a letter to his parents saying he intended to become an engineer. After finishing basic education at the top of his class in 1873, he enrolled at the newly founded Industrial School of Augsburg. Two years later, he received a merit scholarship from the Royal Bavarian Polytechnic of Munich, which he accepted against his parents' wishes, who wanted him to begin working instead.

Reader's Guide

Rudolf Diesel's significance lies in his invention of the diesel engine. One of his professors in Munich was Carl von Linde. Diesel was unable to graduate with his class in July 1879 because he fell ill with typhoid fever. While waiting for the next examination date, he gained practical engineering experience at the Sulzer Brothers Machine Works in Winterthur, Switzerland. Diesel graduated in January 1880 with highest academic honours and returned to Paris, where he assisted Linde with the design and construction of a modern refrigeration and ice plant. Diesel became the director of the plant a year afterwards. In 1883, Diesel married Martha Flasche, and continued to work for Linde, gaining numerous patents in both Germany and France. In early 1890, Diesel moved to Berlin with his wife and children, Rudolf Jr, Heddy, and Eugen, to assume management of Linde's corporate research and development department. Since he was not allowed to use for his own purposes the patents he developed while an employee of Linde's, he expanded beyond refrigeration. He first worked with steam, his research into thermal efficiency and fuel efficiency leading him to build a steam engine using ammonia vapor. During tests, the engine exploded and almost killed him. His research into high-compression cylinder pressures tested the strength of iron and steel cylinder heads. One exploded during a test run. He spent many months in a hospital, followed by health and eyesight problems. It was during this year that Diesel began conceptualising the idea of a diesel engine. In 1892, after working on this idea for several years, he considered his theory to be completed. In the same year, Diesel was given the German patent DRP 67207. In 1893, he published a treatise entitled 'Theory and Construction of a Rational Heat-engine to Replace the Steam Engine and The Combustion Engines Known Today'. By summer 1893, Diesel had realised that his initial theory was erroneous, leading him to file another patent application for the corrected theory in 1893. From 1893 to 1897, Heinrich von Buz, director of Maschinenfabrik Augsburg, provided Diesel the opportunity to test and develop his ideas. Diesel also received support from the Krupp firm. The first successful diesel engine Motor 250/400 was officially tested in 1897, featuring a 25 horsepower four-stroke, single vertical cylinder compression. It became an immediate success, with royalties amassing great wealth for Diesel. The engine is currently on display at the German Technical Museum in Munich. Besides Germany, Diesel obtained patents for his design in other countries, including the United States (1895, 1898). The primary fuel used in Diesel engines today is the eponymous diesel fuel, derived from crude oil. While developing his engine, Diesel tested a wide range of liquid fuels, primarily coal distillates and petroleum products. Diesel also considered using coal dust, and he demonstrated vegetable oil as fuel. In a book titled 'Diesel Engines for Land and Marine Work', Diesel wrote: 'In 1900 a small Diesel engine was exhibited by the Otto company which, on the suggestion of the French Government, was run on arachide [peanut] oil, and operated so well that very few people were aware of the fact. The motor was built for ordinary oils, and without any modification was run on vegetable oil. I have recently repeated these experiments on a large scale with full success and entire confirmation of the results formerly obtained.' On the evening of 29 September 1913, Diesel boarded the Great Eastern Railway steamer SS Dresden in Antwerp on his way to a meeting of the Consolidated Diesel Manufacturing company in London. He took dinner on board and then retired to his cabin at about 10 p.m., leaving word to be called the next morning at 6:15 a.m., but he was never seen alive again. In the morning his cabin was empty and his bed had not been slept in, although his nightshirt was neatly laid out and his watch had been left where it could be seen from the bed. His hat and neatly folded overcoat were discovered beneath the afterdeck railing. Shortly after Diesel's disappearance, his wife Martha opened a bag that her husband had given to her just before his ill-fated voyage, with directions that it should not be opened until the following week. She discovered 20,000 German marks in cash and financial statements indicating that their bank accounts were virtually empty. In a diary Diesel brought with him on the ship, for the date 29 September 1913, a cross was drawn, possibly indicating death. Ten days after he was last seen, the crew of the Dutch pilot boat Coertsen came upon the corpse of a man floating in the Eastern Scheldt. The body was in such an advanced state of decomposition that it was unrecognisable, and they did not retain it aboard because of heavy weather. Instead, the crew retrieved personal items (pill case, wallet, I.D. card, pocketknife, eyeglass case) from the clothing of the dead man, and returned the body to the sea. On 13 October, these items were identified by Rudolf's son, Eugen Diesel, as belonging to his father. Five months later, in March 1914, a rumor emerged that Diesel was in Canada and his wife, Martha, seemed to go missing in Germany. Martha ultimately died in Brandenburg on 16 April 1944, at age 85. There are various theories to explain Diesel's death. Some, such as Diesel's biographers Grosser (1978) and Sittauer (1978) have argued that he died by suicide. Another line of thought suggests that he was murdered, given his refusal to grant the German forces the exclusive rights to using his invention; indeed, Diesel had boarded Dresden with the intent of meeting with representatives of the Royal Navy to discuss the possibility of powering British submarines by diesel engine. Another theory is that his apparent death was a ruse staged by the British government to cover his defection to the British cause, and that he then went to Canada, worked for the Vickers shipyard in Montreal and was responsible for a sudden acceleration in its ability to produce a successful Diesel engine for submarines. Given the limited evidence at hand, his disappearance and death remain unsolved.

Did You Know?

• Rudolf Diesel was born in Paris, France, to Bavarian immigrant parents.
• At age 12, Diesel received the Société pour l'Instruction Elémentaire bronze medal for being a very good student.
• Diesel's first successful diesel engine, Motor 250/400, was officially tested in 1897 and featured a 25 horsepower four-stroke single vertical cylinder.
• In 1900, a small Diesel engine was run on peanut oil at the suggestion of the French Government, and it operated so well that few people were aware of the fact.
• Diesel's disappearance and death in 1913 remain unsolved, with theories including suicide, murder, and a staged defection to Canada.

Common Misconceptions (Editorial)

1. A common misconception is that Rudolf Diesel was born in Germany. In fact, he was born in Paris, France, to Bavarian immigrant parents. 2. Some people believe Diesel invented his engine to run on diesel fuel from the start. However, in 1900 a small Diesel engine was successfully run on peanut oil at the suggestion of the French Government.

Why It Matters (Editorial)

Rudolf Diesel’s invention transformed global industry and transportation, but his life also illustrates the enduring tension between innovation and commercial practicality. His mysterious disappearance in 1913 adds a haunting, unresolved chapter to the story of a man whose work reshaped the modern world.