Editing Diesel fuel (section)

=== Origins ===
Diesel fuel originated from experiments conducted by German scientist and inventor [[Rudolf Diesel]] for his [[compression-ignition engine]] which he invented around 1892. Originally, Diesel did not consider using any specific type of fuel. Instead, he claimed that the operating principle of his [[Theory and Construction of a Rational Heat Motor|rational heat motor]] would work with any kind of fuel in any state of matter.<ref>{{patent|DE|67207|Rudolf Diesel: "Arbeitsverfahren und Ausführungsart für Verbrennungskraftmaschinen" pg 4.}}: "Alle Brennmaterialien in allen Aggregatzuständen sind für Durchführung des Verfahrens brauchbar."</ref> The first diesel engine prototype and the first functional Diesel engine were only designed for liquid fuels.<ref>Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, {{ISBN|978-3-642-64940-0}} p. 125</ref>

At first, Diesel tested [[crude oil]] from [[Pechelbronn]], but soon replaced it with [[petrol]] and [[kerosene]], because crude oil proved to be too viscous,<ref>Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, {{ISBN|978-3-642-64940-0}} p. 107</ref> with the main testing fuel for the Diesel engine being kerosene ([[Mineral oil|paraffin]]).<ref>Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, {{ISBN|978-3-642-64940-0}} p. 108</ref> Diesel experimented with types of [[lamp oil]] from various sources, as well as types of petrol and [[ligroin]], which all worked well as Diesel engine fuels. Later, Diesel tested [[coal tar]] [[creosote]],<ref>Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, {{ISBN|978-3-642-64940-0}} p. 110</ref> paraffin oil, crude oil, [[gasoline]] and [[fuel oil]], which eventually worked as well.<ref>Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, {{ISBN|978-3-642-64940-0}} p. 111</ref> In Scotland and France, [[shale oil]] was used as fuel for the first 1898 production Diesel engines because other fuels were too expensive.<ref>Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, {{ISBN|978-3-642-64940-0}} p. 114</ref> In 1900, the French Otto society built a Diesel engine for the use with crude oil, which was exhibited at the [[Exposition Universelle (1900)|1900 Paris Exposition]]<ref name="Diesel_115">Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, {{ISBN|978-3-642-64940-0}} p. 115</ref> and the 1911 World's Fair in Paris.<ref>{{cite book |author=Ayhan Demirbas |title=Biodiesel: A Realistic Fuel Alternative for Diesel Engines |publisher=Springer |location=Berlin |year=2008 |pages=74 |isbn=978-1-84628-994-1 |url= https://books.google.com/books?id=0vBalrSH_OEC&q=Rudolf+Diesel+vegetable&pg=PA74}}</ref> The engine actually ran on [[peanut oil]] instead of crude oil, and no modifications were necessary for peanut oil operation.<ref name="Diesel_115" />

During his first Diesel engine tests, Diesel also used [[illuminating gas]] as fuel, and managed to build functional designs, both with and without pilot injection.<ref>Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, {{ISBN|978-3-642-64940-0}} p. 116</ref> According to Diesel, neither was a coal-dust–producing industry existent, nor was fine, high-quality coal-dust commercially available in the late 1890s. This is the reason why the Diesel engine was never designed or planned as a coal-dust engine.<ref>Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, {{ISBN|978-3-642-64940-0}} p. 126</ref> Only in December 1899, did Diesel test a coal-dust prototype, which used external mixture formation and liquid fuel pilot injection.<ref>Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, {{ISBN|978-3-642-64940-0}} p. 127</ref> This engine proved to be functional, but suffered from piston ring failure after a few minutes due to coal dust deposition.<ref>Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaues von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}} p. 499</ref>