Dr Rudolph Diesel

Did the Kaiser kill Dr Diesel?
In September 1913 Rover sent one of its test drivers on a confidential mission. Young Dudley Noble was summoned to take a new 12 HP Rover car to Harwich and meet the celebrated Dr Rudolph Diesel off the overnight ferry.
Noble later became head of Rover publicity and, as a career journalist in the 1950s, was a founding father of the Guild of Motoring Writers. He had photographs of Dr Diesel, a letter of introduction, and instructions to bring him to Coventry as soon as he disembarked.
Noble waited in the cold grey light of an autumn dawn, at the exit from the Harwich customs shed, in vain. Dr Diesel had been on the cross-Channel packet “SS Dresden’s” passenger list, but there was no sign of him. His cabin was empty, his bed had not been slept in and he was presumed lost overboard, together with a dispatch case he had when he boarded the ship in Antwerp.
Mystery still surrounds the fate of the man (left) who lent his name to the only real challenger the spark-ignition petrol engine ever had. Some sort of nervous collapse was talked about, but whether he was pushed or fell remains uncertain.
In 1913 small high-speed diesel engines for cars were still a long way off. Dr Diesel had not been first with engines that relied on the heat generated by compression to ignite the fuel. In 1824 Nicholas Leonard Sadi Carnot - the son of Napoleon’s chief of staff the mathematician Lazare Carnot - laid down its principles in the course of devising the mathematical foundation of thermodynamics. He provided a detailed description of the ideal heat engine but never made one.
In 1890 Herbert Ackroyd Stuart patented an oil-fired engine, which was produced by Richard Hornsby & Sons of Grantham, Lincolnshire. One was sold to Newport Sanitary Authority, but the compression ratio was too low for it to be started from cold, and it needed a heat poultice to get it going.
Another Hornsby-Ackroyd Patent Safety Oil Traction engine was sold in 1897 to Hugh Fortescue Locke-King, builder of the Brooklands race track near Weybridge, probably for use as a generator. But although Hornsby advertised four sizes of engine, between 16 and 30 horse power, no more seem to have been sold.
Yet in at least one respect Ackroyd’s engine was closer to the modern compression ignition engine than Diesel’s 1892 patent. It injected fuel into the cylinders by means of a plunger pump. Diesel relied instead on a high-pressure jet of air, a system whose shortcomings frustrated him for the rest of his life.
He once said, “Inventing is the process of sorting one good basic idea out of a multitude of mistakes, and pursuing it through a series of failures and compromises, to practical success.”
The most serious of his failures was inability to manufacture an efficient fuel injection pump. Disheartened, he even contemplated abandoning his rational principle, and applying spark ignition. It was not until ten years after Dr Diesel’s death that Robert Bosch developed a high pressure supply pump, with injectors, to atomise the fuel into a fine mist. It could then be introduced into the cylinders at the right time, opening the way to small, efficient, high speed engines of the sort Diesel was hoping to discuss with Rover in 1913.
Born in Paris in 1858 of a French mother and German father, solitary taciturn Rudolf Diesel had a difficult childhood. He graduated from technical high school at the age of twelve just as the Franco-Prussian war sent the family fleeing to London.
When he returned to France, Diesel attended the Conservatoire des Arts et Metiers, until 1878 when he moved to the Augsburg Technical High school near Munich. Ironically, for the creator of one of the world’s notable heat engines, he studied under Carl von Linde, a pioneer of refrigeration technology.
In his capacity as sales manager for the Linde Ice-Making Company, Diesel’s scrutiny of compression machinery led him to take a fresh look at Carnot’s Napoleonic theories. Diesel took out his first patent on 28 February 1892 and the following year produced a paper,”The Theory and Construction of a Rational Heat Motor”. He also engaged the help of Krupp and the Maschinenfabrik Augsburg (later MAN the truck manufacturer) to provide financial backing and a workshop.
One of his first engines exploded with such violence that it nearly killed him. Undeterred, he took out an improved patent in August 1893, which included his troublesome air-jet injection system, then embarked on a four year research programme. It was only in 1908, thanks to work by a British engineer James McKechnie, that injection pumps were made capable of delivering fuel at a pressure of 50 atmospheres.
In the course of developing his “rational heat engine”, Diesel tried ammonia gas, then coal as fuel. There was still no industrial complex to import oil; the most popular fuel was coal gas on which the early internal combustion engines of Otto and Lenoir relied. Maybach effectively invented the carburettor only by applying a petrol-soaked rag to the intake of a gas engine. Diesel’s experiments with liquified coal were encouraged by Krupp as a means of by-passing the gasworks.
Diesel’s engine was capable of burning oil more or less as it came out of the well; Maybach’s petrol engine demanded refined spirit. Diesel’s conviction that the best way to ignite the mixture by compressing it was sound, and although he never really solved the problem of getting the fuel in properly, he improved the engine’s efficiency sufficiently to make it a working proposition.
Diesel’s pioneering work ensured that it was his name, and not Ackroyd Stuart’s or even Carnot’s that became enshrined in automotive history. By 1897 he was able to dispose of the American rights for his engine, to the German-American brewer Adolphus Busch, for a million marks ($250,000). Some say that Diesel worked himself to exhaustion, and from then on, his mind began to go. Busch was slow to make much of his investment although one engine was built by the St Louis Iron & Marine works, and in 1898 was installed in the Anheuser Busch Brewery, in St Louis, Missouri.
Fuel injection on large diesel engines did not present the same problems of miniaturisation, and it was soon apparent that besides power generation on land, there were useful applications for diesel engines at sea, particularly in submarines.
Electric motors were the only practical motive power for a submarine submerged. Anything else produced heat, fumes, and exhaust gas. Petrol engines were used to charge up the batteries and propel the vessel on the surface and by 1905 a U-boat could do 11 knots or up to 9 knots under water. But in February 1906 one of the German fleet was destroyed by fire when refuelling. Diesel was the answer. The fuel had a lower flash-point than petrol, less was lost through evaporation, it was more economical, and the submarine had a longer range. By the time U19 was laid down in 1911, it was equipped with two strong diesels.
In 1906 the French navy commissioned the diesel-engined underwater-craft Opale and Emeraude, in 1907 the Russians completed the first diesel-engined oil tanker, and in May 1908 Britain’s first diesel submarine the D.1 was launched at Barrow. Soon the First Lord of the Admiralty, Winston Chuchill (right), set off in a diesel submarine from Portsmouth.
With an eye on the menacing nature of the German fleet, Churchill was eager to match its submarine-building programme. Alas he found, “... great technical difficulties, and the delays of the contractors vexatious in the extreme.”
Dr Diesel’s engine was accordingly of great strategic importance. It is possible that the Kaiser’s government might have been less than happy at the prospect of him sharing secrets with the British Admiralty. It is equally possible that Diesel’s disappearance in the Channel could have had something to do with the Krupp shipyard’s new-found interest in exporting U-boat technology. With Diesel on the loose, Churchill might get the help he needed more or less free.
Jane’s Fighting Ships of 1914 contained an advertisement featuring a submarine Krupp built for the Italian navy, which looked like an invitation to meet the technical difficulties, and replace the contractors that so worried Mr Churchill.
We shall never know whether it was cloak and dagger work by the Kaiser’s secret service, industrial espionage on a grand scale, a depressive mood following another failure of his fuel injectors, or merely the heaving deck of a cross-Channel packet-boat that deprived the world of Rudolph Diesel. Yet to survive as an internationally recognised generic term is some sort of lasting tribute.

The Times: Diesel special report 29 April 1992, reproduced in Eric Dymock on Cars 1992.