Rudolf Diesel

Rudolf Diesel
It is generally known that vegetable oils and animal fats were investigated as diesel fuels well before the energy crises of the 1970s and early 1980s sparked renewed interest in alternative fuels. It is also known that Rudolf Diesel (1858–1913), the
inventor of the engine that bears his name, had some interest in these fuels. However,the early history of vegetable oil-based diesel fuels is often presented inconsistently, and “facts” that are not compatible with Diesel’s own statements are encountered freq u e n t l y .
Therefore, it is appropriate to begin this history with the words of Diesel himselfin his book Die Entstehung des Dieselmotors (1) [The Development (or Creation or Rise o r C o m i n g) of the Diesel Engine] in which he describes when the first seed ofdeveloping what was to become the diesel engine was planted in his mind. In the first chapter of the book entitled “The Idea,” Diesel states: “When my highly respected teacher, Professor Linde, explained to his listeners during the lecture on thermodynamics in 1878 at the P o l y t e c h n i k u m in Munich (note: now the Technical University
of Munich) that the steam engine only converts 6–10% of the available heat content of the fuel into work, when he explained Carnot’s theorem and elaborated that during the isothermal change of state of a gas all transferred heat is converted into work, I wrote in the margin of my notebook: ‘Study, if it isn’t possible to practically realize the isotherm!’ At that time I challenged myself! That was not yet an invention, not even the idea for it. From then on, the desire to realize the ideal Carnot process determined my existence. I left the school, joined the practical side, had to achieve my standing in
life. The thought constantly pursued me.”
This statement by Diesel clearly shows that he approached the development of the diesel engine from a thermodynamic point of view. The objective was to develop an efficient engine. The relatively common assertion made today that Diesel developed
“his” engine specifically to use vegetable oils as fuel is therefore incorrect. In a later chapter of his book entitled “Liquid Fuels,” Diesel addresses the use of vegetable oils as a fuel: “For [the] sake of completeness it needs to be mentioned that already in the year 1900 plant oils were used successfully in a diesel engine. During the Paris Exposition in 1900, a small diesel engine was operated on arachide (peanut) oil by the French Otto Company. It worked so well that only a few insiders knew about this inconspicuous circumstance. The engine was built for petroleum and was used for the plant oil without any change. In this case also, the consumption experiments resulted in heat utilization identical to petroleum.” A total of five diesel engines,