As the story goes, Rudolf Diesels earth-shattering invention was inspired by a lighter, which was ignited simply through the compression of air. After the granting of patents for his "theory and construction of a rational caloric engine", it took more than four years and cost him two forerunners, before he presented, on the 28th of January, 1897, in co-operation with the Machine factory Augsburg Nuremberg (MAN), and previously, the Krupp concern, a working engine. (see above figure) It was three metres high, weighed four tons, and probably produced 20 Hp from approx. 20,000 cc capacity at 172 RPM, its piston alone weighed 50 kg. In the following summer it was presented to the public. A model of the machine can be seen in the German museum in Munich. The efficiency ratio of approx. 27% was a sensation at that time. The working method was, a single-cylinder, four-stroke engine with water-cooling and fuel/air carburation.

In contrast to Nikolaus Otto, a merchant, who invented the four-stroke engine, Rudolf Diesel was an engineer. He was born in 1858 in Paris and studied in Augsburg and Munich. He was actually occupied with refrigeration technology in the Linde company. However, during his stay in Berlin, he succeeded in working out the theoretical conception of combustion initiated by the high compression of air alone, followed by the injection of fuel. It was not until 1925 that the engine started to become wide spread, because that was when Robert Bosch invented the high-pressure fuel injection pump, which was absolutely necessary to the diesel principle. Only then did the diesel engine conquer the utility vehicle sector, later, also the railway and shipping areas. In 1936 the first passenger car with a diesel engine was produced.

Rudolf Diesels invention apparently brought him very little happiness. Although he was honoured at the 1900 world exhibition in Paris, and had made a fortune through the sales of licences, which he lost again just as quickly, through speculation. He committed suicide while crossing the English Channel on the 30th of September, 1913.

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