On 27 February 1892 Rudolf Diesel applied to the Imperial Patent Office in Berlin for a patent on a Neue rationelle Wärmekraftmaschine, a new rational heat engine. He received it on 23 February 1893, as a patent on a working process for combustion engines. In 1893 he also published a book: Theorie und Konstruktion eines rationellen Wärmemotors, Theory and Construction of a Rational Heat Engine. Through the book he came into contact with Heinrich von Buz, the general director of the Maschinenfabrik Augsburg. From 1893, with financial support from Krupp, Diesel developed his engine there. The first ignition came on 10 August 1893. The first working engine was finished in 1897. German Wikipedia notes: Aus der geplanten halbjährigen Entwicklungszeit waren vier lange Jahre mit zahlreichen Rückschlägen geworden. (The planned half year of development had become four long years with many setbacks.)