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If Rudolf Diesel hadn't been born, quite possibly the road transport industry would have had to invent him - without him the eponymous engine might never have existed. Born of German parents on 18 March 1858 in Paris, Rudolf Christian Karl Diesel was ultimately denied the honour of witnessing his invention achieve its greatest impact: after dinner on 29 September 1913 on board the SS Dresden, crossing the Channel from Antwerp to Harwich, he left word to be woken at 6.15am, but come the morning  he could not be found. Ten days later his body was found off the Dutch coast.

Star pupil

In his late teens, Diesel studied mechanical engineering at the College of Mechanical Engineering in Munich. It was here that he attended a lecture by Professor Carl Linde and learnt of the poor efficiency of the steam engine and of French scientist Sadi Carnot's 'cyclic process' that would generate a significantly higher yield. His calling now apparent, in 1880 Diesel graduated with the highest honours since the founding of the college. For the next 10 years he took charge of the French branch of Linde's refrigeration machinery factory. During this time, working in his own time, and on his own initiative, Diesel built a steam engine powered by ammonia vapour. Under test, the engine exploded, nearly killing Diesel and putting him in hospital for many months. In 1890, he moved from Paris to Berlin to become head of engineering at Linde's engineering office.

Despite the ammonia  engine setback, he continued to pursue his "task" of developing an efficient heat engine. In February 1892, he applied for a patent, finally granted nearly a year later on 23 February 1893, for a process by which "pure air or another indifferent gas (or steam) with pure air is compressed by the working piston in a cylinder to such an extent that the resultant temperature lies well above the ignition temperature of the fuel that is to be used, whereupon the admission of the fuel is effected from dead centre onwards so gradually that combustion occurs without a substantial increase in pressure or temperature on account of the return stroke of the piston and the consequent expansion of the compressed air (or gas), whereupon the further expansion of the gas mass in the working cylinder takes place after fuel admission has ended".

During the year-long ordeal to secure this patent, Diesel realised considerable funding would be required to turn his process into reality. Thus he signed contracts with both MAN and another company, Krupp of Essen. The contracts allowed Diesel to become self-employed in 1893.

Testing

The two companies co-operated, testing an engine derived from Diesel's patents and designs in MAN's lab in July 1893. The experimental engine failed to operate at first. Further development meant the engine idled for the first time in February 1894. It took more than another year for the engine to demonstrate an effective power output: on 26 June 1895, the engine measured an efficiency of 16.6% (without the direct injection specified in Diesel's patent as manufacturing capabilities were limited). This, the first 'diesel' engine (right), is now housed in the MAN museum.

Backed by MAN's then-chairman Heinrich Buz, development continued, until, on 17 February 1897, the engine was officially tested by the Munich College of Engineering. The engine, running at between 154rpm and 172rpm, produced 18hp with an efficiency rating of 26%, comfortably ahead of steam's 12%. The diesel engine's future was assured.

Commercial launch

The engine was commercially launched in 1898. Many applications for the engine followed and, by 1913, Diesel estimated that engines in operation or under construction, derived from his design, accounted for a total output of 1.7 million hp. MAN-manufactured engines accounted for 25% of these. Then came that fateful journey aboard the SS Dresden. It wasn't until 1923 that a direct fuel injection diesel automotive engine, as we would recognise it today, was produced by MAN. The four-cylinder, four-stroke unit put out at 40hp at 900rpm. The rest is history - and a legacy Rudolf Diesel would surely be proud of.