Editing Diesel fuel (section)

=== Since the 20th century ===

Before diesel fuel was standardised, diesel engines typically ran on cheap fuel oils. In the United States, these were distilled from petroleum, whereas in Europe, coal-tar creosote oil was used. Some diesel engines were fuelled with mixtures of fuels, such as petrol, kerosene, rapeseed oil, or lubricating oil which were cheaper because, at the time, they were not being taxed.<ref>Hans Christian Graf von Seherr-Thoß (auth.): Die Technik des MAN Nutzfahrzeugbaus. In: MAN Nutzfahrzeuge AG (ed.): Leistung und Weg: Zur Geschichte des MAN Nutzfahrzeugbaus. Springer, Berlin/Heidelberg 1991. {{ISBN|978-3-642-93490-2}}. p. 436</ref> The introduction of motor-vehicle diesel engines, such as the [[Mercedes-Benz OM 138]], in the 1930s meant that higher-quality fuels with proper ignition characteristics were needed. At first no improvements were made to motor-vehicle diesel fuel quality. After World War II, the first modern high-quality diesel fuels were standardised. These standards were, for instance, the DIN 51601, VTL 9140–001, and NATO F 54 standards.<ref name="Seher-Thoß_437">Hans Christian Graf von Seherr-Thoß (auth.): Die Technik des MAN Nutzfahrzeugbaus. In: MAN Nutzfahrzeuge AG (ed.): Leistung und Weg: Zur Geschichte des MAN Nutzfahrzeugbaus. Springer, Berlin/Heidelberg 1991. {{ISBN|978-3-642-93490-2}}. p. 437</ref> In 1993, the DIN 51601 was rendered obsolete by the new EN 590 standard, which has been used in the European Union ever since. In sea-going watercraft, where diesel propulsion had gained prevalence by the late 1970s due to increasing fuel costs caused by the [[1970s energy crisis]], cheap [[heavy fuel oil]]s are still used instead of conventional motor-vehicle diesel fuel. These heavy fuel oils (often called [[Bunker C]]) can be used in diesel-powered and steam-powered vessels.<ref name="Mau_13">Günter Mau: Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb, Springer-Vieweg, Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 13</ref>