View source for Diesel engine

{{Short description|Type of internal combustion engine}}
{{About||the locomotive|Diesel locomotive|the game engine|Diesel (game engine)}}
{{Use mdy dates|date=June 2013}}
{{Infobox machine
| image             =
| caption           = Diesel engine built by Langen & Wolf under licence, 1898
| classification    = [[Internal combustion engine]]
| industry          = [[Automotive industry|Automotive]]
| application       = [[Energy transformation]]
| inventor          = [[Rudolf Diesel]]
| invented          = {{start date and age|df=7|p=y|1893}}
}}
[[File:The Diesel Story.ogv|thumb|right|1952 [[Shell Oil]] film showing the development of the diesel engine from 1877]]

The '''diesel engine''', named after the German engineer [[Rudolf Diesel]], is an [[internal combustion engine]] in which [[Combustion|ignition]] of [[diesel fuel]] is caused by the elevated temperature of the air in the cylinder due to [[Mechanics|mechanical]] [[Compression (physics)|compression]]; thus, the diesel engine is called a '''compression-ignition engine''' (or '''CI engine'''). This contrasts with engines using [[spark plug]]-ignition of the air-fuel mixture, such as a [[petrol engine]] ([[gasoline]] engine) or a [[gas engine]] (using a gaseous fuel like [[natural gas]] or [[liquefied petroleum gas]]).

{{TOC limit|3}}

==Introduction==
Diesel engines work by compressing only air, or air combined with residual combustion gases from the exhaust (known as [[exhaust gas recirculation]], "EGR"). Air is inducted into the chamber during the intake stroke, and compressed during the compression stroke. This increases air temperature inside the [[Cylinder (engine)|cylinder]] so that atomised diesel fuel injected into the combustion chamber ignites. The torque a diesel engine produces is controlled by manipulating the [[Air–fuel ratio#Air–fuel equivalence ratio (λ)|air-fuel ratio (λ)]]; instead of throttling the intake air, the diesel engine relies on altering the amount of fuel that is injected, and thus the air-fuel ratio is usually high.{{cn|date=August 2025}}

The diesel engine has the highest [[thermal efficiency]] ''(see [[engine efficiency]])'' of any practical [[internal combustion|internal]] or [[external combustion]] engine due to its very high [[expansion ratio]] and inherent [[Air–fuel ratio|lean]] burn, which enables heat dissipation by excess air. A small efficiency loss is also avoided compared with non-direct-injection gasoline engines, as unburned fuel is not present during valve overlap, and therefore no fuel goes directly from the intake/injection to the exhaust. Low-speed diesel engines (as used in ships and other applications where overall engine weight is relatively unimportant) can reach effective efficiencies of up to 55%.<ref name="Reif_2014_13" /> The [[combined cycle power plant|combined cycle gas turbine]] (Brayton and Rankine cycle) is a combustion engine that is more efficient than a diesel engine, but due to its mass and dimensions, is unsuitable for many vehicles, including [[watercraft]] and some [[aircraft]]. The world's largest diesel engines put in service are 14-cylinder, two-stroke marine diesel engines; they produce a peak power of almost 100&nbsp;MW each.<ref name="Grote_2018_P93" />

Diesel engines may be designed with either [[two-stroke engine|two-stroke]] or [[four-stroke]] [[#Combustion cycle|combustion cycles]]. They were originally used as a more efficient replacement for stationary [[steam engine]]s. Since the 1910s, they have been used in [[submarine]]s and ships. Use in [[locomotives]], buses, trucks, [[heavy equipment]], agricultural equipment and electricity generation plants followed later. In the 1930s, they slowly began to be used in some [[automobile]]s. Since the [[1970s energy crisis]], demand for higher fuel efficiency has resulted in most major automakers, at some point, offering diesel-powered models, even in very small cars.<ref name="time_forgot_2021_04_13_autoweek_com">{{citation | last = Ramey | first = Jay | url = https://www.autoweek.com/car-life/classic-cars/g36106078/diesel-cars-time-forgot/ | archive-url = https://web.archive.org/web/20221206053344/https://www.autoweek.com/car-life/classic-cars/g36106078/diesel-cars-time-forgot/ | archive-date = 2022-12-06 | title = 10 Diesel Cars That Time Forgot | date = April 13, 2021 | work = [[Autoweek]] | publisher = Hearst Autos, Inc. }}</ref><ref name="critical_evaluation_2013_springeropen_com">[https://enveurope.springeropen.com/articles/10.1186/2190-4715-25-15 "Critical evaluation of the European diesel car boom - global comparison, environmental effects and various national strategies,"] 2013, ''Environmental Sciences Europe,'' volume&nbsp;25, Article&nbsp;number:&nbsp;15, retrieved December 5, 2022</ref> According to Konrad Reif (2012), the [[European Union|EU]] average for diesel cars at the time accounted for half of newly registered cars.<ref name="Reif_2012_286" /> However, [[air pollution]] and overall emissions are more difficult to control in diesel engines compared to gasoline engines, so the use of diesel engines in the US is now largely relegated to larger on-road and [[off-road vehicle]]s.<ref name="every_new_diesel_2021_03_06_caranddriver_com">Huffman, John Pearley: [https://www.caranddriver.com/features/g20980996/diesel-car-truck-suv/ "Every New 2021 Diesel for Sale in the U.S. Today,"] March 6, 2021, ''[[Car and Driver]],'' retrieved December 5, 2022</ref><ref name="the_15_best_2021_04_23_usnews_com">Gorzelany, Jim: [https://cars.usnews.com/cars-trucks/advice/best-diesel-cars?slide=18 "The Best 15 Best Diesel Vehicles of 2021,"] April 23, 2021, ''[[U.S. News]],'' retrieved December 5, 2022</ref>

Though aviation has traditionally avoided using diesel engines, aircraft diesel engines have become increasingly available in the 21st century. Since the late 1990s, for various reasons—including diesel's inherent advantages over gasoline engines, but also for recent issues peculiar to aviation—development and production of diesel engines for aircraft has surged, with over 5,000 such engines delivered worldwide between 2002 and 2018, particularly for [[Light aircraft|light airplanes]] and [[unmanned aerial vehicles]].<ref name="inside_2018_08_01_flyingmag_com">[https://www.flyingmag.com/inside-aviation-diesel-revolution/ "Inside the Diesel Revolution,"] August 1, 2018, ''[[Flying (magazine)|Flying]],''  retrieved December 5, 2022</ref><ref name="diamond_2020_12_30_avweb_com">O'Connor, Kate: [https://www.avweb.com/aviation-news/diamond-rolls-out-500th-da40-ng/ "Diamond Rolls Out 500th DA40 NG,"] December 30, 2020 Updated: December 31, 2020, ''[[Avweb]],'' retrieved December 5, 2022</ref>

==History==

===Diesel's idea===
[[File:Lumbar patent dieselengine.jpg|thumb|right|[[Rudolf Diesel]]'s 1893 patent on a rational heat motor]]
[[File:Experimental Diesel Engine.jpg|thumb|right|Diesel's second prototype. It is a modification of the first experimental engine. On 17 February 1894, this engine ran under its own power for the first time.<ref name="Diesel_1913_22" /><br /><br />Effective efficiency 16.6% <br />Fuel consumption 519&nbsp;g·kW<sup>−1</sup>·h<sup>−1</sup>]]

In 1878, [[Rudolf Diesel]], who was a student at the [[Technical University of Munich#Foundation of "Polytechnische Schule München"|"Polytechnikum"]] in [[Munich]], attended the lectures of [[Carl von Linde]]. Linde explained that steam engines are capable of converting just 6–10% of the heat energy into work, but that the [[Carnot cycle]] allows conversion of much more of the heat energy into work by means of isothermal change in condition. According to Diesel, this ignited the idea of creating a highly efficient engine that could work on the Carnot cycle.<ref name="Diesel_1913_1" /> Diesel was also introduced to a [[fire piston]], a traditional [[fire making|fire starter]] using rapid [[adiabatic]] compression principles which Linde had acquired from [[Southeast Asia]].<ref name="ogata">{{Cite web |last1=Ogata |first1=Masanori |last2=Shimotsuma |first2=Yorikazu |date=October 20–21, 2002 |title=Origin of Diesel Engine is in Fire Piston of Mountainous People Lived in Southeast Asia |url=http://inet.museum.kyoto-u.ac.jp/conference02/MasanoriOGATA.html |url-status=dead |archive-url=https://web.archive.org/web/20070523214754/http://inet.museum.kyoto-u.ac.jp/conference02/MasanoriOGATA.html |archive-date=May 23, 2007 |access-date=2007-05-28 |website=First International Conference on Business and technology Transfer |publisher=Japan Society of Mechanical Engineers}}</ref> After several years of working on his ideas, Diesel published them in 1893 in the essay ''[[Theory and Construction of a Rational Heat Motor]]''.<ref name="Diesel_1913_1" />

====Constant temperature====
Diesel was heavily criticised for his essay, but only a few found the mistake that he made;<ref name="Sittauer_1990_70" /> his ''rational heat motor'' was supposed to utilise a constant temperature cycle (with isothermal compression) that would require a much higher level of compression than that needed for compression ignition. Diesel's idea was to compress the air so tightly that the temperature of the air would exceed that of combustion. However, such an engine could never perform any usable work.<ref name="Sittauer_1990_71" /><ref name="Sass_1962_398" /><ref name="Sass_1962_399" /> In his 1892 US patent (granted in 1895) #542846, Diesel describes the compression required for his cycle:<ref name="Diesel_1895" />

{{blockquote|pure atmospheric air is compressed, according to curve 1 2, to such a degree that, before ignition or combustion takes place, the highest pressure of the diagram and the highest temperature are obtained-that is to say, the temperature at which the subsequent combustion has to take place, not the burning or igniting point. To make this more clear, let it be assumed that the subsequent combustion shall take place at a temperature of 700°. Then in that case the initial pressure must be sixty-four atmospheres, or for 800° centigrade the pressure must be ninety atmospheres, and so on. Into the air thus compressed is then gradually introduced from the exterior finely divided fuel, which ignites on introduction, since the air is at a temperature far above the igniting-point of the fuel. The characteristic features of the cycle according to my present invention are therefore, increase of pressure and temperature up to the maximum, not by combustion, but prior to combustion by mechanical compression of air, and there upon the subsequent performance of work without increase of pressure and temperature by gradual combustion during a prescribed part of the stroke determined by the cut-oil.}}

====Constant pressure====
By June 1893, Diesel had realised his original cycle would not work, and he adopted the constant pressure cycle.<ref name="Sass_1962_402" /> Diesel describes the cycle in his 1895 patent application. Notice that there is no longer a mention of compression temperatures exceeding the temperature of combustion. Now it is simply stated that the compression must be sufficient to trigger ignition.<ref name="Diesel_1898" /><ref name="Diesel_1893" /><ref name="e-rara.ch" />

{{blockquote|1. In an internal-combustion engine, the combination of a cylinder and piston constructed and arranged to compress air to a degree producing a temperature above the igniting-point of the fuel, a supply for compressed air or gas; a fuel-supply; a distributing-valve for fuel, a passage from the air supply to the cylinder in communication with the fuel-distributing valve, an inlet to the cylinder in communication with the air-supply and with the fuel-valve, and a cut-oil, substantially as described.}}

In 1892, Diesel received patents in [[German Empire|Germany]], [[Switzerland]], the [[United Kingdom of Great Britain and Ireland|United Kingdom]], and the [[United States]] for "Method of and Apparatus for Converting Heat into Work".<ref name="Diesel_1892" /> In 1894 and 1895, he filed patents and addenda in various countries for his engine; the first patents were issued in [[Spain]] (No.&nbsp;16,654),<ref>{{patent|ES|16654|"Perfeccionamientos en los motores de combustión interior."}}</ref> [[France]] (No.&nbsp;243,531) and [[Belgium]] (No.&nbsp;113,139) in December 1894, and in [[Germany]] (No.&nbsp;86,633) in 1895 and the [[United States]] (No.&nbsp;608,845) in 1898.<ref name="Diesel_1895_2" />

Diesel was attacked and criticised over several years. Critics claimed that Diesel never invented a new motor and that the invention of the diesel engine is fraud. Otto Köhler and {{ill|Emil Capitaine|de}} were two of the most prominent critics of Diesel's time.<ref name="Sass_1962_486" /> Köhler had published an essay in 1887, in which he describes an engine similar to the engine Diesel describes in his 1893 essay. Köhler figured that such an engine could not perform any work.<ref name="Sass_1962_399" /><ref name="Sass_1962_400" /> Emil Capitaine had built a petroleum engine with glow-tube ignition in the early 1890s;<ref name="Sass_1962_412" /> he claimed against his own better judgement that his glow-tube ignition engine worked the same way Diesel's engine did. His claims were unfounded and he lost a patent lawsuit against Diesel.<ref name="Sass_1962_487" /> Other engines, such as the [[Hot-bulb engine|Akroyd engine]] and the [[Brayton engine]], also use an operating cycle that is different from the diesel engine cycle.<ref name="Sass_1962_400" /><ref name="Sass_1962_414" /> [[Friedrich Sass]] says that the diesel engine is Diesel's "very own work" and that any "Diesel myth" is "[[falsification of history]]".<ref name="Sass_1962_518" />

===The first diesel engine===
[[File:Historical Diesel engine in Deutsches Museum.jpg|thumb|right|First fully functional diesel engine, designed by Imanuel Lauster, built from scratch, and finished by October 1896.<ref name="Diesel_1913_64" /><ref name="Diesel_1913_75" /><ref name="Diesel_1913_78" /><br /><br />Rated power 13.1&nbsp;kW<br />Effective efficiency 26.2% <br />Fuel consumption 324&nbsp;g·kW<sup>−1</sup>·h<sup>−1</sup>.]]
Diesel sought out firms and factories that would build his engine. With the help of [[Moritz Schröter]] and {{interlanguage link|Max Friedrich Gutermuth{{!}}Max Gutermuth|de|Max Gutermuth}},<ref name="Sass_1962_395" /> he succeeded in convincing both [[Krupp]] in Essen and the [[MAN SE|Maschinenfabrik Augsburg]].<ref name="Sittauer_1990_74" /> Contracts were signed in April 1893,<ref name="Sass_1962_559" /> and in early summer 1893, Diesel's first prototype engine was built in [[Augsburg]]. On 10 August 1893, the first ignition took place, the fuel used was petrol. In winter 1893/1894, Diesel redesigned the existing engine, and by 18 January 1894, his mechanics had converted it into the second prototype.<ref name="Diesel_1913_17" /> During January that year, an [[air-blast injection]] system was added to the engine's cylinder head and tested.<ref name="Sass_1962_444" /> [[Friedrich Sass]] argues that, it can be presumed that Diesel copied the concept of air-blast injection from [[George B. Brayton]],<ref name="Sass_1962_414" /> albeit that Diesel substantially improved the system.<ref name="Sass_1962_415" /> On 17 February 1894, the redesigned engine ran for 88 revolutions – one minute;<ref name="Diesel_1913_22" /> with this news, Maschinenfabrik Augsburg's stock rose by 30%, indicative of the tremendous anticipated demands for a more efficient engine.<ref name="Moon_1974" /> On 26 June 1895, the engine achieved an effective efficiency of 16.6% and had a fuel consumption of 519&nbsp;g·kW<sup>−1</sup>·h<sup>−1</sup>.
<ref name="Tschöke_2018_6" /> However, despite proving the concept, the engine caused problems,<ref name="Sass_1962_462" /> and Diesel could not achieve any substantial progress.<ref name="Sass_1962_463" /> Therefore, Krupp considered rescinding the contract they had made with Diesel.<ref name="Sass_1962_464" /> Diesel was forced to improve the design of his engine and rushed to construct a third prototype engine. Between 8 November and 20 December 1895, the second prototype had successfully covered over 111 hours on the test bench. In the January 1896 report, this was considered a success.<ref name="Sass_1962_466" />

In February 1896, Diesel considered supercharging the third prototype.<ref name="Sass_1962_467" /> [[Imanuel Lauster]], who was ordered to draw the third prototype "[[Motor 250/400]]", had finished the drawings by 30 April 1896. During summer that year the engine was built, it was completed on 6 October 1896.<ref name="Sass_1962_474" /> Tests were conducted until early 1897.<ref name="Sass_1962_475" /> First public tests began on 1 February 1897.<ref name="Sass_1962_479" /> [[Moritz Schröter]]'s test on 17 February 1897 was the main test of Diesel's engine. The engine was rated 13.1&nbsp;kW with a specific fuel consumption of 324&nbsp;g·kW<sup>−1</sup>·h<sup>−1</sup>,<ref name="Sass_1962_480" /> resulting in an effective efficiency of 26.2%.<ref name="Tschöke_2018_7" /><ref name="Mau_1984_7" /> By 1898, Diesel had become a millionaire.<ref name="Sass_1962_484" />

===Timeline===
====1890s====
* 1893: [[Rudolf Diesel]]'s essay titled ''[[Theory and Construction of a Rational Heat Motor]]'' appears.<ref name="Diesel_1893_EN" /><ref name="Diesel_1893_1" />
* 1893: February 21, Diesel and the Maschinenfabrik Augsburg sign a contract that allows Diesel to build a prototype engine.<ref name="Diesel_1913_6" />
* 1893: February 23, Diesel obtains a patent (RP 67207) titled "''Arbeitsverfahren und Ausführungsart für Verbrennungsmaschinen''" (Working Methods and Techniques for Internal Combustion Engines).
* 1893: April 10, Diesel and Krupp sign a contract that allows Diesel to build a prototype engine.<ref name="Diesel_1913_6" />
* 1893: April 24, both Krupp and the Maschinenfabrik Augsburg decide to collaborate and build just a single prototype in Augsburg.<ref name="Diesel_1913_6" /><ref name="Sass_1962_559" />
* 1893: July, the first prototype is completed.<ref name="Diesel_1913_8" />
* 1893: August 10, Diesel injects fuel (petrol) for the first time, resulting in combustion, destroying the [[Indicator diagram|indicator]].<ref name="Diesel_1913_13" />
* 1893: November 30, Diesel applies for a patent (RP 82168) for a modified combustion process. He obtains it on 12 July 1895.<ref name="Diesel_1913_21" /><ref>{{patent|DE|82168|"Verbrennungskraftmaschine mit veränderlicher Dauer der unter wechselndem Überdruck stattfindenden Brennstoffeinführung"}}</ref><ref name="Sass_1962_408" />
* 1894: January 18, after the first prototype was modified to become the second prototype, testing with the second prototype begins.<ref name="Diesel_1913_17" />
* 1894: February 17, The second prototype runs for the first time.<ref name="Diesel_1913_22" />
* 1895: March 30, Diesel applies for a patent (RP 86633) for a starting process with compressed air.<ref name="Diesel_1913_38" />
* 1895: June 26, the second prototype passes brake testing for the first time.<ref name="Tschöke_2018_6" />
* 1895: Diesel applies for a second patent US Patent # 608845<ref name="Diesel_1895_EN" />
* 1895: November 8 – December 20, a series of tests with the second prototype is conducted. In total, 111 operating hours are recorded.<ref name="Sass_1962_466" />
* 1896: April 30, [[Imanuel Lauster]] completes the third and final prototype's drawings.<ref name="Sass_1962_474" />
* 1896: October 6, the third and final prototype engine is completed.<ref name="Diesel_1913_64" />
* 1897: February 1, Diesel's prototype engine is running and finally ready for efficiency testing and production.<ref name="Sass_1962_479" />
* 1897: October 9, [[Adolphus Busch]] licenses rights to the diesel engine for the US and Canada.<ref name="Sass_1962_484" /><ref name="Busch" />
* 1897: 29 October, Rudolf Diesel obtains a patent (DRP 95680) on supercharging the diesel engine.<ref name="Sass_1962_467" />
* 1898: February 1, the Diesel Motoren-Fabrik Actien-Gesellschaft is registered.<ref name="Sass_1962_485" />
* 1898: March, the first commercial diesel engine, rated 2×30&nbsp;PS (2×22&nbsp;kW), is installed in the Kempten plant of the Vereinigte Zündholzfabriken A.G.<ref name="Sass_1962_505" /><ref name="Sass_1962_506" />
* 1898: September 17, the Allgemeine Gesellschaft für Dieselmotoren A.-G. is founded.<ref name="Sass_1962_493" />
* 1899: The first two-stroke diesel engine, invented by [[Hugo Güldner]], is built.<ref name="Mau_1984_7" />

====1900s====
[[File:Dieselmotor vs.jpg|thumb|right|An MAN DM trunk piston diesel engine built in 1906. The MAN DM series is considered to be one of the first commercially successful diesel engines.<ref name="Sass_1962_524" />]]
* 1901: Imanuel Lauster designs the first [[trunk piston]] diesel engine (DM 70).<ref name="Sass_1962_524" />
* 1901: By 1901, [[MAN SE|MAN]] had produced 77 diesel engine cylinders for commercial use.<ref name="Sass_1962_523" />
* 1903: Two first diesel-powered ships are launched, both for river and canal operations: The ''[[Vandal (tanker)|Vandal]]'' [[naphtha]] tanker and the ''[[Samrat (ship)|Sarmat]]''.<ref name="Sass_1962_532" />
* 1904: The French launch the first diesel [[submarine]], the [[Aigrette-class submarine|Aigrette]].<ref name="Tucker2014" />
* 1905: January 14: Diesel applies for a patent on unit injection (L20510I/46a).<ref name="Sass_1962_501" />
* 1905: The first diesel engine [[turbocharger]]s and [[intercooler]]s are manufactured by Büchi.<ref name="Hartman" />
* 1906: The Diesel Motoren-Fabrik Actien-Gesellschaft is dissolved.<ref name="Sass_1962_486" />
* 1908: Diesel's patents expire.<ref name="Sass_1962_530" />
* 1908: The first lorry ([[truck]]) with a diesel engine appears.<ref name="Reif_O_2014_7" />
* 1909: March 14, [[Prosper L'Orange]] applies for a patent on [[indirect injection#Precombustion chamber|precombustion chamber injection]].<ref name="Sass_1962_610" />  He later builds the first diesel engine with this system.<ref name="vFersen_1986_272" /><ref name="Merker_2014_382" />

====1910s====
* 1910: MAN starts making two-stroke diesel engines.<ref name="Mau_1984_8" />
* 1910: November 26, [[James McKechnie (engineer)|James McKechnie]] applies for a patent on [[unit injector|unit injection]].<ref name="Tschöke_2018_10" /> Unlike Diesel, he successfully built working unit injectors.<ref name="Sass_1962_501" /><ref name="Sass_1962_502" />
* 1911: November 27, the Allgemeine Gesellschaft für Dieselmotoren A.-G. is dissolved.<ref name="Sass_1962_485" />
* 1911: The Germania shipyard in Kiel builds {{convert|850|PS|kW|0|abbr=on}} diesel engines for German submarines. These engines are installed in 1914.<ref name="Sass_1962_569" />
* 1912: MAN builds the first double-acting piston two-stroke diesel engine.<ref name="Sass_1962_545" />
* 1912: The first [[locomotive]] with a diesel engine is used on the Swiss [[Winterthur–Romanshorn railway]].<ref name="Klooster2009" />
* 1912: [[MS Selandia|MS ''Selandia'']] is the first ocean-going ship with diesel engines.<ref name="Tschöke_2018_9" />
* 1913: [[New London Ship and Engine Company|NELSECO]] diesels are installed on commercial ships and [[United States Navy|US Navy]] submarines.<ref name="RiversHarbors" />
* 1913: September 29, [[Rudolf Diesel]] dies mysteriously while crossing the [[English Channel]] on {{SS|Dresden|1896|6}}.<ref name="Solomon" />
* 1914: MAN builds {{convert|900|PS|kW|0|abbr=on}} two-stroke engines for Dutch submarines.<ref name="Sass_1962_541" />
* 1919: Prosper L'Orange obtains a patent on a [[Indirect injection#Precombustion chamber|precombustion chamber]] insert incorporating a needle [[fuel injection|injection nozzle]].<ref name="Pease2003" /><ref name="AutomobileQuarterly" /><ref name="Merker_2014_382" /> First diesel engine from [[Cummins]].<ref name="Bennett2016" /><ref name="DictionaryCH" />

====1920s====
[[File:Fairbanks Morse model 32.jpg|thumb|Fairbanks Morse model 32]]
* 1923: At the Königsberg DLG exhibition, the first agricultural tractor with a diesel engine, the prototype Benz-Sendling S6, is presented.<ref name="Agritechnica_2017" />{{Better source needed|date=February 2019}}
* 1923: December 15, the first [[lorry]] with a direct-injected diesel engine is tested by MAN. The same year, Benz builds a lorry with a pre-combustion chamber injected diesel engine.<ref name="MAN_1991_XI" />
* 1923: The first two-stroke diesel engine with counterflow scavenging appears.<ref name="Mau_1984_17" />
* 1924: [[Fairbanks-Morse]] introduces the two-stroke Y-VA (later renamed to Model 32).<ref name="Oldmachinepress_2012" />
* 1925: Sendling starts mass-producing a diesel-powered agricultural tractor.<ref name="Sass_1962_644" />
* 1927: [[Robert Bosch GmbH|Bosch]] introduces the first inline injection pump for motor vehicle diesel engines.<ref name="Reif_2014_31" />
* 1929: The first passenger car with a diesel engine appears. Its engine is an Otto engine modified to use the diesel principle and Bosch's injection pump. Several other diesel car prototypes follow.<ref name="vFersen_1986_274" />

====1930s====
* 1933: [[Junkers (Aircraft)|Junkers Motorenwerke]] in Germany start production of the most successful mass-produced aviation diesel engine of all time, the [[Junkers Jumo 205|Jumo 205]]. By the outbreak of [[World War II]], over 900 examples are produced. Its rated take-off power is 645&nbsp;kW.<ref name="Reif_2012_103" />
* 1933: General Motors uses its new roots-blown, unit-injected two-stroke Winton 201A diesel engine to power its automotive assembly exhibit at the Chicago World's Fair (''[[A Century of Progress]]'').<ref name="EuDaly_2016_160" /> The engine is offered in several versions ranging from {{cvt|600-900|hp|kW|0}}.<ref name="Kremser_1942_24" />
* 1934: The [[Budd Company]] builds the first diesel–electric passenger train in the US, the ''[[Pioneer Zephyr]] 9900'', using a Winton engine.<ref name="EuDaly_2016_160" />
* 1935: The [[Citroën Rosalie]] is fitted with an early [[swirl chamber injection|swirl chamber injected]] diesel engine for testing purposes.<ref name="Cole_2014_64" /> [[Daimler-Benz]] starts manufacturing the [[Mercedes-Benz OM 138]], the first mass-produced diesel engine for passenger cars, and one of the few marketable passenger car diesel engines of its time. It is rated {{cvt|45|PS|kW|0}}.<ref name="Kremser_1942_125" />
*1935: The [[International Harvester]] Company develops a diesel engine that starts on gasoline to warm up before switching over to diesel fuel. The engine is then put in their model WD-40 tractor.<ref>Wendel, C.H (1981); 150 years of International Harvester, ISBN 978-0879386832</ref>
* 1936: March 4, the airship [[LZ 129 Hindenburg]], the biggest aircraft ever made, takes off for the first time. It is powered by four V16 Daimler-Benz LOF 6 diesel engines, rated {{cvt|1200|PS|kW|0}} each.<ref name="Waibel_2016_159" />
* 1936: Manufacture of the first mass-produced passenger car with a diesel engine ([[Mercedes-Benz 260 D]]) begins.<ref name="vFersen_1986_274" />
* 1937: [[Konstantin Chelpan|Konstantin Fyodorovich Chelpan]] develops the [[Kharkiv model V-2|V-2]] diesel engine, later used in the Soviet [[T-34]] tanks, widely regarded as the best tank chassis of World War II.<ref name="Tucker-Jones_2015_36" />
* 1938: [[General Motors]] forms the GM Diesel Division, later to become [[Detroit Diesel]], and introduces the [[Series 71]] [[Straight engine|inline]] high-speed medium-horsepower [[Two-stroke diesel engine|two-stroke]] engine, suitable for road vehicles and marine use.<ref name="FleetOwner_1964_107" />

====1940s====
* 1946: [[Clessie Cummins]] obtains a patent on a ''fuel feeding and injection apparatus for oil-burning engines'' that incorporates separate components for generating injection pressure and injection timing.<ref name="Cummins_1946" />
* 1946: [[Klöckner-Humboldt-Deutz]] (KHD) introduces an air-cooled mass-production diesel engine to the market.<ref name="Flatz_1946" />

====1950s====
[[File:ZT 303 Motor.jpg|thumb|Piston of an MAN [[M-System]] centre sphere combustion chamber type diesel engine ([[4 VD 14,5/12-1 SRW]])]]
* 1950s: [[Klöckner-Humboldt-Deutz|KHD]] becomes the air-cooled diesel engine global market leader.<ref name="Tschöke_2018_666" />
* 1951: J. Siegfried Meurer obtains a patent on the ''[[M-System]]'', a design that incorporates a central sphere combustion chamber in the piston (DBP 865683).<ref name="MAN_465" />
* 1953: First mass-produced [[Indirect injection#Swirl chamber|swirl chamber injected]] passenger car diesel engine (Borgward/Fiat).<ref name="Tschöke_2018_10" />
* 1954: Daimler-Benz introduces the [[Mercedes-Benz OM 312|Mercedes-Benz OM 312 A]], a 4.6 litre straight-6 series-production industrial diesel engine with a turbocharger, rated {{convert|115|PS|kW|abbr=on}}. It proves to be unreliable.<ref name="Daimler_2009_2" />
* 1954: [[Volvo]] produces a small batch series of 200 units of a turbocharged version of the TD 96 engine. This 9.6 litre engine is rated {{convert|136|kW|PS|abbr=on}}.<ref name="vFersen_1987_156" />
* 1955: Turbocharging for MAN two-stroke marine diesel engines becomes standard.<ref name="Mau_1984_17" />
* 1959: The [[Peugeot 403]] becomes the first mass-produced passenger sedan/saloon manufactured outside [[West Germany]] to be offered with a diesel engine option.<ref name="Peugeot403gazole">{{Cite web |last=Andrew Roberts |date=10 July 2007 |title=Peugeot 403 |url=https://www.independent.co.uk/life-style/motoring/features/peugeot-403-5529921.html |access-date=28 February 2019 |website=The 403, launched half a century ago, established Peugeot as a global brand. |publisher=[[The Independent]], [[London]]}}</ref>

====1960s====
[[File:OM 352.jpg|thumb|[[Mercedes-Benz OM352 engine|Mercedes-Benz OM 352]], one of the first direct injected Mercedes-Benz diesel engines. It was introduced in 1963, but mass production only started in summer 1964.<ref name="Vogler_2016_34" />]]
* 1964: Summer, Daimler-Benz switches from [[indirect injection#Precombustion chamber|precombustion chamber injection]] to helix-controlled direct injection.<ref name="Daimler_2009" /><ref name="MAN_465" />
* 1962–65: A [[Compression release engine brake|diesel compression braking system]], eventually to be manufactured by the [[Jacobs Vehicle Systems|Jacobs Manufacturing Company]] and nicknamed the "Jake Brake", is invented and patented by Clessie Cummins.<ref name="Cummins_1965" />

====1970s====
* 1972: KHD introduces the [[AD-System]], ''Allstoff-Direkteinspritzung'', (anyfuel direct-injection), for its diesel engines. AD-diesels can operate on virtually any kind of liquid fuel, but they are fitted with an auxiliary spark plug that fires if the ignition quality of the fuel is too low.<ref name="vBasshuysen_2017_24" />
* 1976: Development of the [[common rail]] injection begins at the ETH Zürich.<ref name="vBasshuysen_2017_141" />
* 1976: The [[Volkswagen Golf Mk1#Golf Diesel|Volkswagen Golf]] becomes the first compact passenger sedan/saloon to be offered with a diesel engine option.<ref name="GoDilautSpiegel401976">{{Cite magazine |date=27 September 1976 |title=Blauer Rauch |url=http://www.spiegel.de/spiegel/print/d-41136373.html |magazine=Der VW-Konzern präsentiert seine neuesten Golf-Variante – den ersten Wolfsburger Personenwagen mit Dieselmotor. |publisher=[[Der Spiegel]] (online) |volume=40/1976 |access-date=28 February 2019}}</ref><ref name="GoDivolgensGA">{{Cite web |last=Georg Auer |date=21 May 2001 |title=How Volkswagen built a diesel dynasty |url=https://europe.autonews.com/article/20010521/ANE/105210844/how-volkswagen-built-a-diesel-dynasty |access-date=28 February 2019 |website=Automotive News Europe |publisher=Crain Communications, Inc., Detroit MI}}</ref>
* 1978: Daimler-Benz produces the first passenger car diesel engine with a turbocharger ([[Mercedes-Benz OM617 engine]]).<ref name="Merker_2014_179" />
* 1979: First prototype of a low-speed two-stroke crosshead engine with common rail injection.<ref name="Merker_2014_276" />

====1980s====
* 1981/82: Uniflow scavenging for two-stroke marine diesel engines becomes standard.<ref name="Mau_1984_16" />
* 1982: August, Toyota introduces a microprocessor-controlled [[engine control unit]] (ECU) for Diesel engines to the Japanese market.<ref name="Kawai Miyagi Nakano Kondo 1985 pp. 289–293">{{cite journal | last1=Kawai | first1=Mitsuo | last2=Miyagi | first2=Hideo | last3=Nakano | first3=Jiro | last4=Kondo | first4=Yoshihiko | title=Toyota's New Microprocessor-Based Diesel Engine Control System for Passenger Cars | journal=IEEE Transactions on Industrial Electronics | volume=IE-32 | issue=4 | date=1985 | issn=0278-0046 | doi=10.1109/TIE.1985.350099 | pages=289–293}}</ref>
* 1985: December, road testing of a common rail injection system for lorries using a modified 6VD 12,5/12 GRF-E engine in an [[IFA W50]] takes place.<ref name="Diehl_2013_100" />
* 1987: Daimler-Benz introduces the electronically controlled injection pump for lorry diesel engines.<ref name="Tschöke_2018_10" />
* 1988: The [[Fiat Croma]] becomes the first mass-produced passenger car in the world to have a [[#Direct injection|direct injected]] diesel engine.<ref name="Tschöke_2018_10" />
* 1989: The [[Audi 100]] is the first passenger car in the world with a turbocharged, intercooled, direct-injected, and electronically controlled diesel engine.<ref name="Tschöke_2018_10" /> It has a [[BMEP]] of 1.35&nbsp;MPa and a [[Brake-specific fuel consumption|BSFC]] of 198&nbsp;g/(kW·h).<ref name="Stock Bauder 1990 p. 87">{{cite conference | last1=Stock | first1=Dieter | last2=Bauder | first2=Richard | title=SAE Technical Paper Series | chapter=The New Audi 5-Cylinder Turbo Diesel Engine: The First Passenger Car Diesel Engine with Second Generation Direct Injection | date=1990-02-01 | volume=1 | doi=10.4271/900648 | page=87}}</ref>

====1990s====
* 1992: 1 July, the [[Euro 1]] emission standard comes into effect.<ref name="Reif_2014_182" />
* 1993: First passenger car diesel engine with four valves per cylinder, the Mercedes-Benz OM 604.<ref name="Merker_2014_179" />
* 1994: Unit injector system by Bosch for lorry diesel engines.<ref name="Reif_2012_271" />
* 1996: First diesel engine with direct injection and four valves per cylinder, used in the [[Opel Vectra]].<ref name="Zhao_2009_8" /><ref name="Tschöke_2018_10" />
* 1996: First radial piston distributor injection pump by Bosch.<ref name="Reif_2012_271" />
* 1997: First mass-produced [[common rail]] diesel engine for a passenger car, the Fiat 1.9 JTD.<ref name="Tschöke_2018_10" /><ref name="Merker_2014_179" />
* 1998: BMW wins the [[24 Hours Nürburgring]] race with a modified [[BMW E36]]. The car, called 320d, is powered by a 2-litre, straight-four diesel engine with direct injection and a helix-controlled distributor injection pump (Bosch VP 44), producing {{convert|180|kW|hp|abbr=on}}. The fuel consumption is 23&nbsp;L/100&nbsp;km, only half the fuel consumption of a similar Otto-powered car.<ref name="Reif_2012_223" />
* 1998: [[Volkswagen]] introduces the [[List of Volkswagen Group diesel engines#EA188|VW EA188 Pumpe-Düse engine]] (1.9 TDI), with Bosch-developed electronically controlled [[unit injector]]s.<ref name="Merker_2014_179" />
* 1999: Daimler-Chrysler presents the first [[common rail]] three-cylinder diesel engine used in a passenger car (the [[Smart City Coupé]]).<ref name="Tschöke_2018_10" />

====2000s====
[[File:Neckarsulm-AudiForum-Audi-R10-TDI.jpg|thumb|Audi R10 TDI, 2006 24 Hours of Le Mans winner.]]
* 2000: Peugeot introduces the diesel particulate filter for passenger cars.<ref name="Tschöke_2018_10" /><ref name="Merker_2014_179" />
* 2002: [[Piezoelectric]] injector technology by Siemens.<ref name="Egger_2002" />
* 2003: Piezoelectric injector technology by Bosch,<ref name="Speck_2005" /> and Delphi.<ref name="TheEngineer_2003" />
* 2004: BMW introduces dual-stage turbocharging with the [[BMW M57]] engine.<ref name="Merker_2014_179" />
* 2006: The world's most powerful diesel engine, the [[Wärtsilä-Sulzer RTA96-C]], is produced. It is rated 80,080&nbsp;kW.<ref name="Tschöke_2018_1110" />
* 2006: [[Audi R10 TDI]], equipped with a 5.5-litre V12-TDI engine, rated {{convert|476|kW|hp|abbr=on}}, wins the [[2006 24 Hours of Le Mans]].<ref name="Tschöke_2018_10" />
* 2006: Daimler-Chrysler launches the first series-production passenger car engine with [[selective catalytic reduction]] exhaust gas treatment, the [[Mercedes-Benz OM642 engine|Mercedes-Benz OM 642]]. It is fully complying with the Tier2Bin8 emission standard.<ref name="Merker_2014_179" />
* 2008: Volkswagen introduces the [[NOx adsorber|LNT catalyst]] for passenger car diesel engines with the [[List of Volkswagen Group diesel engines#EA189|VW 2.0 TDI engine]].<ref name="Merker_2014_179" />
* 2008: Volkswagen starts series production of the biggest passenger car diesel engine, the Audi 6-litre V12 TDI.<ref name="Merker_2014_179" />
* 2008: [[Subaru]] introduces the first [[horizontally opposed]] diesel engine to be fitted to a passenger car. It is a 2-litre common rail engine, rated 110&nbsp;kW.<ref name="Zhao_2009_45" />

====2010s====
* 2010: [[Mitsubishi Motors|Mitsubishi]] developed and started mass production of its [[Mitsubishi 4N1 engine|4N13]] 1.8&nbsp;L DOHC I4, the world's first passenger car diesel engine that features a [[variable valve timing]] system.<ref name="Long_2013" />
* 2012: BMW introduces dual-stage turbocharging with three turbochargers for the [[BMW N57]] engine.<ref name="Merker_2014_179" />
* 2015: [[Common rail]] systems working with pressures of 2,500 bar launched.<ref name="Tschöke_2018_10" />
* 2015: In the [[Volkswagen emissions scandal]], the [[United States Environmental Protection Agency|US EPA]] issued a notice of violation of the [[Clean Air Act (United States)|Clean Air Act]] to [[Volkswagen Group]] after it was found that Volkswagen had intentionally programmed [[turbocharged direct injection]] (TDI) diesel engines to activate certain [[Exhaust gas|emissions]] controls only during laboratory [[emissions testing]].<ref name="Jordans_2015" /><ref name="EPA_2015" /><ref name="NPR_2015" /><ref name="Spiegel_2015" />

==Operating principle==

=== Overview ===
The characteristics of a diesel engine are<ref name="Pischinger_2016_348" />
* Use of [[compression ignition]], instead of an ignition apparatus such as a [[Spark-ignition engine|spark plug]].
* Internal mixture formation. In diesel engines, the mixture of air and fuel is only formed inside the combustion chamber.
* Quality torque control. The amount of torque a diesel engine produces is not controlled by throttling the intake air (unlike a traditional spark-ignition petrol engine, where the airflow is reduced in order to regulate the torque output), instead, the volume of air entering the engine is maximised at all times, and the torque output is regulated solely by controlling the amount of injected fuel.
* High [[Air–fuel ratio#Air–fuel equivalence ratio (λ)|air-fuel ratio]]. Diesel engines run at global air-fuel ratios significantly leaner than the [[Stoichiometry#Stoichiometric ratio|stoichiometric ratio]].
* [[Diffusion flame]]: At combustion, oxygen first has to diffuse into the flame, rather than having oxygen and fuel already mixed before combustion, which would result in a [[premixed flame]].
* [[Heterogeneous]] air-fuel mixture: In diesel engines, there is no even dispersion of fuel and air inside the cylinder. That is because the combustion process begins at the end of the injection phase, before a homogeneous mixture of air and fuel can be formed.
* Preference for the fuel to have a high ignition performance ([[Cetane number]]), rather than a high knocking resistance ([[octane rating]]) that is preferred for petrol engines.

=== Thermodynamic cycle ===
{{technical|section|date=July 2022}}
[[File:Model Engine Luc Viatour.jpg|thumb|Diesel engine model, left side]]
[[File:Model Engine B Luc Viatour.jpg|thumb|Diesel engine model, right side]]
{{See also|Diesel cycle|Reciprocating internal combustion engine}}

The diesel internal combustion engine differs from the gasoline powered [[Otto cycle]] by using highly compressed hot air to ignite the fuel rather than using a spark plug (''compression ignition'' rather than ''spark ignition'').

In the diesel engine, only air is initially introduced into the combustion chamber. The air is then compressed with a compression ratio typically between 15:1 and 23:1. This high compression causes the temperature of the air to rise. At about the top of the compression stroke, fuel is injected directly into the compressed air in the combustion chamber. This may be into a (typically [[toroid]]al) void in the top of the piston or a ''pre-chamber'' depending upon the design of the engine. The fuel injector ensures that the fuel is broken down into small droplets, and that the fuel is distributed evenly. The heat of the compressed air vaporises fuel from the surface of the droplets. The vapour is then ignited by the heat from the compressed air in the combustion chamber, the droplets continue to vaporise from their surfaces and burn, getting smaller, until all the fuel in the droplets has been burnt. Combustion occurs at a substantially constant pressure during the initial part of the power stroke. The start of vaporisation causes a delay before ignition and the characteristic diesel knocking sound as the vapour reaches ignition temperature and causes an abrupt increase in pressure above the piston (not shown on the P-V indicator diagram). When combustion is complete the combustion gases expand as the piston descends further; the high pressure in the cylinder drives the piston downward, supplying power to the [[crankshaft]].

As well as the high level of compression allowing combustion to take place without a separate ignition system, a high [[compression ratio]] greatly increases the engine's efficiency. Increasing the compression ratio in a spark-ignition engine where fuel and air are mixed before entry to the cylinder is limited by the need to prevent [[pre-ignition#Pre-ignition|pre-ignition]]<!-- detonation from occurring after ignition and is more a fuel quality or combustion chamber design issue -->, which would cause engine damage. Since only air is compressed in a diesel engine, and fuel is not introduced into the cylinder until shortly before top dead centre ([[Top Dead Center|TDC]]), premature detonation is not a problem and compression ratios are much higher.

[[File:DieselCycle PV.svg|thumb|right|pV diagram for the ideal diesel cycle (which follows the numbers 1–4 in clockwise direction). The horizontal axis is the cylinder volume. In the diesel cycle the combustion occurs at almost constant pressure. On this diagram the work that is generated for each cycle corresponds to the area within the loop.]]
The [[pressure–volume diagram]] (pV) diagram is a simplified and idealised representation of the events involved in a diesel engine cycle, arranged to illustrate the similarity with a [[Carnot cycle]]. Starting at 1, the piston is at bottom dead centre and both valves are closed at the start of the compression stroke; the cylinder contains air at atmospheric pressure. Between 1 and 2 the air is compressed adiabatically&nbsp;– that is without heat transfer to or from the environment&nbsp;– by the rising piston. (This is only approximately true since there will be some heat exchange with the [[Cylinder (engine)|cylinder walls]].) During this compression, the volume is reduced, the pressure and temperature both rise. At or slightly before 2 (TDC) fuel is injected and burns in the compressed hot air. Chemical energy is released and this constitutes an injection of thermal energy (heat) into the compressed gas. Combustion and heating occur between 2 and 3. In this interval the pressure remains constant since the piston descends, and the volume increases; the temperature rises as a consequence of the energy of combustion. At 3 fuel injection and combustion are complete, and the cylinder contains gas at a higher temperature than at 2. Between 3 and 4 this hot gas expands, again approximately adiabatically. Work is done on the system to which the engine is connected. During this expansion phase the volume of the gas rises, and its temperature and pressure both fall. At 4 the exhaust valve opens, and the pressure falls abruptly to atmospheric (approximately). This is unresisted expansion and no useful work is done by it. Ideally the adiabatic expansion should continue, extending the line 3–4 to the right until the pressure falls to that of the surrounding air, but the loss of efficiency caused by this unresisted expansion is justified by the practical difficulties involved in recovering it (the engine would have to be much larger). After the opening of the exhaust valve, the exhaust stroke follows, but this (and the following induction stroke) are not shown on the diagram. If shown, they would be represented by a low-pressure loop at the bottom of the diagram. At 1 it is assumed that the exhaust and induction strokes have been completed, and the cylinder is again filled with air. The piston-cylinder system absorbs energy between 1 and 2&nbsp;– this is the work needed to compress the air in the cylinder, and is provided by mechanical kinetic energy stored in the flywheel of the engine. Work output is done by the piston-cylinder combination between 2 and 4. The difference between these two increments of work is the indicated work output per cycle, and is represented by the area enclosed by the pV loop. The adiabatic expansion is in a higher pressure range than that of the compression because the gas in the cylinder is hotter during expansion than during compression. It is for this reason that the loop has a finite area, and the net output of work during a cycle is positive.<ref name="Reif_2014_18" />

=== Efficiency ===

The [[fuel efficiency]] of diesel engines is better than most other types of combustion engines,<ref name="Dubbel_1981_712" /><ref name="Reif_2014_10" /> due to their high compression ratio, high [[air-fuel ratio#Air–fuel equivalence ratio (λ)|air–fuel equivalence ratio (λ)]],<ref name="Pischinger Kell Sams p. 137–138">{{Cite book |last1=Pischinger |first1=Rudolf |title=Thermodynamik der Verbrennungskraftmaschine |last2=Kell |first2=Manfred |last3=Sams |first3=Theodor |date=2009 |publisher=Springer-Verlag |isbn=978-3-211-99277-7 |publication-place=Wien |pages=137–138 |language=de |oclc=694772436}}</ref> and the lack of intake air restrictions (i.e. throttle valves). Theoretically, the highest possible efficiency for a diesel engine is 75%.<ref name="Hemmerlein_1991" /> However, in practice the efficiency is much lower, with efficiencies of up to 43% for passenger car engines,<ref name="vB_2017_755" /> up to 45% for large truck and bus engines, and up to 55% for large two-stroke marine engines.<ref name="Reif_2014_13" /><ref name="EPA_2004" /> The average efficiency over a motor vehicle driving cycle is lower than the diesel engine's peak efficiency (for example, a 37% average efficiency for an engine with a peak efficiency of 44%).<ref name="Soimar_2000" /> That is because the fuel efficiency of a diesel engine drops at lower loads, however, it does not drop quite as fast as the Otto (spark ignition) engine's.<ref name="Karle p. 53">{{Cite book |last=Karle |first=Anton |title=Elektromobilität Grundlagen und Praxis; mit 21 Tabellen |date=2015 |isbn=978-3-446-44339-6 |publication-place=München |page=53 |language=de |oclc=898294813}}</ref>

=== Emissions ===
{{see also|Diesel exhaust}}
Diesel engines are combustion engines and, therefore, emit combustion products in their [[exhaust gas]]. Due to incomplete combustion,<ref name="List_1939_1" /> diesel engine exhaust gases include [[carbon monoxide]], [[hydrocarbons]], [[Particulates|particulate matter]], and [[nitrogen oxides]] pollutants. About 90 per cent of the pollutants can be removed from the exhaust gas using exhaust gas treatment technology.<ref name="Dubbel_2018_1191" /><ref name="Reif p. 329">{{Cite book |last=Reif |first=Konrad |title=Diesel engine management : systems and components |date=2014 |publisher=Springer-Verlag |isbn=978-3-658-03981-3 |publication-place=Wiesbaden |page=329 |oclc=884504346}}</ref> Road vehicle diesel engines have no [[sulfur dioxide]] emissions, because motor vehicle diesel fuel has been sulfur-free since 2003.<ref name="Reif p. 331">{{Cite book |last=Reif |first=Konrad |title=Diesel engine management : systems and components |date=2014 |publisher=Springer-Verlag |isbn=978-3-658-03981-3 |publication-place=Wiesbaden |page=331 |oclc=884504346}}</ref> Helmut Tschöke argues that particulate matter emitted from motor vehicles has negative impacts on human health.<ref name="Tschöke Mollenhauer Maier p. 813">{{Cite book |last1=Tschöke |first1=Helmut |title=Handbuch Dieselmotoren |last2=Mollenhauer |first2=Klaus |last3=Maier |first3=Rudolf |date=2018 |publisher=Springer Vieweg |isbn=978-3-658-07697-9 |publication-place=Wiesbaden |page=813 |language=de |oclc=1011252252}}</ref>

The particulate matter in diesel exhaust emissions is sometimes classified as a [[carcinogen]] or "probable carcinogen" and is known to increase the risk of heart and respiratory diseases.<ref>{{Cite web |title=What Are Diesel Emissions? Diesel Engine Exhaust Emissions |url=https://www.nettinc.com/information/emissions-faq/what-are-diesel-emissions |access-date=9 July 2022 |website=www.NettTechnologies.com}}</ref>

=== Electrical system ===
In principle, a diesel engine does not require any sort of electrical system. However, most modern diesel engines are equipped with an electrical fuel pump, and an electronic engine control unit.

However, there is no high-voltage electrical ignition system present in a diesel engine. This eliminates a source of [[Electromagnetic interference|radio frequency emissions]] (which can interfere with navigation and communication equipment), which is why only diesel-powered vehicles are allowed in some parts of the American [[National Radio Quiet Zone]].<ref name="NRAO" />

===Torque control===
To control the torque output at any given time (i.e. when the driver of a car adjusts the [[accelerator pedal]]), a [[governor (device)|governor]] adjusts the amount of fuel injected into the engine. Mechanical governors have been used in the past, however electronic governors are more common on modern engines. Mechanical governors are usually driven by the engine's [[Serpentine belt|accessory belt]] or a gear-drive system<ref name="buckman" /><ref name="Rochester" /> and use a combination of springs and weights to control fuel delivery relative to both load and speed.<ref name=buckman/> Electronically governed engines use an [[electronic control unit]] (ECU) or electronic control module (ECM) to control the fuel delivery. The ECM/ECU uses various sensors (such as engine speed signal, intake manifold pressure and fuel temperature) to determine the amount of fuel injected into the engine.

Due to the amount of air being constant (for a given RPM) while the amount of fuel varies, very high ("lean") air-fuel ratios are used in situations where minimal torque output is required. This differs from a petrol engine, where a [[throttle]] is used to also reduce the amount of intake air as part of regulating the engine's torque output. Controlling the timing of the start of injection of fuel into the cylinder is similar to controlling the ignition timing in a petrol engine. It is therefore a key factor in controlling the power output, fuel consumption and exhaust emissions.

== Classification ==
There are several different ways of categorising diesel engines, as outlined in the following sections.

=== RPM operating range ===
Günter Mau categorises diesel engines by their rotational speeds into three groups:<ref name="Mau_1984_15" />
* High-speed engines (> 1,000 rpm),
* Medium-speed engines (300–1,000 rpm), and
* Slow-speed engines (< 300 rpm).

; High-speed diesel engines
High-speed engines are used to power [[truck]]s (lorries), [[bus]]es, [[tractor]]s, [[automobile|cars]], [[yacht]]s, [[Gas compressor|compressors]], [[pump]]s and small [[electrical generator]]s.<ref name="Reif_2014_11" /> As of 2018, most high-speed engines have [[Direct fuel injection|direct injection]]. Many modern engines, particularly in on-highway applications, have [[common rail]] [[Direct fuel injection|direct injection]].<ref name="Tschöke_2018_295" /> On bigger ships, high-speed diesel engines are often used for powering electric generators.<ref name="Mau_1984_42" /> The highest power output of high-speed diesel engines is approximately 5&nbsp;MW.<ref name="Mau_1984_43" />

; Medium-speed diesel engines
[[File:12 Cylinder Diesel Engine.jpg|thumb|right|Stationary 12 cylinder turbo-diesel engine coupled to a generator set for auxiliary power]]
Medium-speed engines are used in large electrical generators, railway [[diesel locomotive]]s, ship propulsion and mechanical drive applications such as large compressors or pumps. Medium speed diesel engines operate on either diesel fuel or heavy fuel oil by direct injection in the same manner as low-speed engines. Usually, they are four-stroke engines with trunk pistons;<ref name="Mau_1984_33" /> a notable exception being the [[EMD 567]], [[EMD 645|645]], and [[EMD 710|710]] engines, which are all two-stroke.<ref>{{Cite conference |last=Kettering, E.W. |date=29 November 1951 |title=History and Development of the 567 Series General Motors Locomotive Engine |url=https://books.google.com/books?id=QuUiAQAAMAAJ |conference=ASME 1951 Annual Meeting |location=Atlantic City, New Jersey |publisher=Electro-Motive Division, General Motors Corporation}}</ref>

The power output of medium-speed diesel engines can be as high as 21,870&nbsp;kW,<ref name="Mau_1984_136" /> with the effective efficiency being around 47-48% (1982).<ref name="Mau_1984_121" /> Most larger medium-speed engines are started with compressed air direct on pistons, using an air distributor, as opposed to a pneumatic starting motor acting on the flywheel, which tends to be used for smaller engines.<ref name="Merker_2014_280" />

Medium-speed engines intended for marine applications are usually used to power ([[Roll-on/roll-off|ro-ro]]) ferries, passenger ships or small freight ships. Using medium-speed engines reduces the cost of smaller ships and increases their transport capacity. In addition to that, a single ship can use two smaller engines instead of one big engine, which increases the ship's safety.<ref name="Mau_1984_33" />

; Low-speed diesel engines
[[File:5S50MC.jpg|thumb|right|The MAN B&W 5S50MC, a two-stroke, low-speed, [[straight-five engine|inline five-cylinder]] marine diesel engine on board a 29,000 tonne chemical carrier]]

Low-speed diesel engines are usually very large in size and mostly used to power [[ship]]s. There are two different types of low-speed engines that are commonly used: Two-stroke engines with a crosshead, and four-stroke engines with a regular trunk-piston. Two-stroke engines have a limited rotational frequency and their charge exchange is more difficult, which means that they are usually bigger than four-stroke engines and used to directly power a ship's propeller.

Four-stroke engines on ships are usually used to power an electric generator. An electric motor powers the propeller.<ref name="Mau_1984_15" /> Both types are usually very [[Stroke ratio#Undersquare or long-stroke engine|undersquare]], meaning the bore is smaller than the stroke.<ref name="Mau_1984_129" /> Low-speed diesel engines (as used in ships and other applications where overall engine weight is relatively unimportant) often have an effective efficiency of up to 55%.<ref name="Reif_2014_13" /> Like medium-speed engines, low-speed engines are started with compressed air, and they use heavy oil as their primary fuel.<ref name="Merker_2014_280" />

=== Combustion cycle ===
[[File:Uniflow 2-stroke diesel static.svg|thumb|right|Schematic of a two-stroke diesel engine with a roots blower]]
[[File:Detroit Diesel timing.jpg|thumb|Detroit Diesel timing]]

[[Four-stroke engine]]s use the combustion cycle described earlier. Most smaller diesels, for vehicular use, for instance, typically use the four-stroke cycle. This is due to several factors, such as the two-stroke design's narrow powerband which is not particularly suitable for automotive use and the necessity for complicated and expensive built-in lubrication systems and scavenging measures.<ref name=enginebuilder>{{cite web | url = https://www.enginebuildermag.com/2015/01/cars-get-two-stroke-diesels/ | archive-url = https://web.archive.org/web/20221209084324/https://www.enginebuildermag.com/2015/01/cars-get-two-stroke-diesels/ | archive-date = 2022-12-09 | date = 2015-01-11 | title = Could Our Cars Get Two Stroke Diesels? | first = Sterling | last = Shriber | work = Engine Builder | publisher = Babcox Media Inc. }}</ref> The cost effectiveness (and proportion of added weight) of these technologies has less of an impact on larger, more expensive engines, while engines intended for shipping or stationary use can be run at a single speed for long periods.<ref name=enginebuilder/>

[[Two-stroke diesel engine|Two-stroke engines]] use a combustion cycle which is completed in two strokes instead of four strokes. Filling the cylinder with air and compressing it takes place in one stroke, and the power and exhaust strokes are combined. The compression in a two-stroke diesel engine is similar to the compression that takes place in a four-stroke diesel engine: As the piston passes through bottom centre and starts upward, compression commences, culminating in fuel injection and ignition. Instead of a full set of valves, two-stroke diesel engines have simple intake ports, and exhaust ports (or exhaust valves). When the piston approaches bottom dead centre, both the intake and the exhaust ports are "open", which means that there is atmospheric pressure inside the cylinder. Therefore, some sort of pump is required to blow the air into the cylinder and the combustion gasses into the exhaust. This process is called ''scavenging''. The pressure required is approximately 10-30&nbsp;kPa.<ref name="Mau_1984_50" />

Due to the lack of discrete exhaust and intake strokes, all two-stroke diesel engines use a [[scavenge blower]] or some form of compressor to charge the cylinders with air and assist in scavenging.<ref name="Mau_1984_50" /> Roots-type superchargers were used for ship engines until the mid-1950s, however since 1955 they have been widely replaced by turbochargers.<ref name="Mau_1984_23" /> Usually, a two-stroke ship diesel engine has a single-stage turbocharger with a turbine that has an axial inflow and a radial outflow.<ref name="Mau_1984_pp53" />

==== Scavenging in two-stroke engines====
In general, there are three types of scavenging possible:
* Uniflow scavenging
* Crossflow scavenging
* [[Schnuerle porting|Reverse flow scavenging]]

Crossflow scavenging is incomplete and limits the stroke, yet some manufacturers used it.<ref name="Mau_1984_148" /> Reverse flow scavenging is a very simple way of scavenging, and it was popular amongst manufacturers until the early 1980s. Uniflow scavenging is more complicated to make but allows the highest fuel efficiency; since the early 1980s, manufacturers such as MAN and Sulzer have switched to this system.<ref name="Mau_1984_16" /> It is standard for modern marine two-stroke diesel engines.<ref name="Grote_2018_P93" />

=== Fuel used ===
{{Main|Bi-fuel vehicle#Diesel conversions}}
So-called dual-fuel diesel engines or gas diesel engines burn two different types of fuel ''simultaneously'', for instance, a gaseous fuel and diesel engine fuel. The diesel engine fuel auto-ignites due to compression ignition, and then ignites the gaseous fuel. Such engines do not require any type of spark ignition and operate similar to regular diesel engines.<ref name="Karim_2015_2" /><ref>{{cite web|url=http://www.dualfuel.org/wp-content/uploads/2022/03/DFPS-Brochure.pdf|title=DFPS Brochure|website=dualfuel.org}}</ref>

==Fuel injection==
The fuel is injected at high pressure into either the [[combustion chamber]], "swirl chamber" or "pre-chamber,"<ref name="Pischinger_2016_348" /> unlike petrol engines where the fuel is often added in the [[manifold injection|inlet manifold]] or [[carburetor]]. Engines where the fuel is injected into the main combustion chamber are called [[direct fuel injection|direct injection]] (DI) engines, while those which use a swirl chamber or pre-chamber are called [[indirect fuel injection|indirect injection]] (IDI) engines.<ref name="Reif_2014_28" />

=== Direct injection ===
[[File:Têtes de piston.svg|thumb|Different types of piston bowls{{explain|date=July 2025}}]]
{{main|Direct fuel injection}}
Most direct injection diesel engines have a combustion cup in the top of the piston where the fuel is sprayed. Many different methods of injection can be used. Usually, an engine with helix-controlled mechanic direct injection has either an inline or a distributor injection pump.<ref name=buckman/> For each engine cylinder, the corresponding plunger in the fuel pump measures out the correct amount of fuel and determines the timing of each injection. These engines use [[fuel injection|injectors]] that are very precise spring-loaded valves that open and close at a specific fuel pressure. Separate high-pressure fuel lines connect the fuel pump with each cylinder. Fuel volume for each single combustion is controlled by a slanted [[Groove (engineering)|groove]] in the plunger which rotates only a few degrees releasing the pressure and is controlled by a mechanical governor, consisting of weights rotating at engine speed constrained by springs and a lever. The injectors are held open by the fuel pressure. On high-speed engines the plunger pumps are together in one unit.<ref name="Firstdiesel_2009" /> The length of fuel lines from the pump to each injector is normally the same for each cylinder in order to obtain the same pressure delay. Direct injected diesel engines usually use orifice-type fuel injectors.<ref name="Reif_2014_140" />

Electronic control of the fuel injection transformed the direct injection engine by allowing much greater control over the combustion.<ref name="Dieselpower_2007" />

; Common rail
[[Common rail]] (CR) direct injection systems do not have the fuel metering, pressure-raising and delivery functions in a single unit, as in the case of a Bosch distributor-type pump, for example. A high-pressure pump supplies the CR. The requirements of each cylinder injector are supplied from this common high pressure reservoir of fuel. An Electronic Diesel Control (EDC) controls both rail pressure and injections depending on engine operating conditions. The injectors of older CR systems have [[solenoid]]-driven plungers for lifting the injection needle, whilst newer CR injectors use plungers driven by [[piezoelectricity|piezoelectric]] actuators that have less moving mass and therefore allow even more injections in a very short period of time.<ref name="Reif_2014_70" />  Early common rail system were controlled by mechanical means.

The injection pressure of modern CR systems ranges from 140&nbsp;MPa to 270&nbsp;MPa.<ref name="Tschöke_2018_310" />

=== Indirect injection ===
[[File:Ricardo comet combustion.gif|thumb|Ricardo Comet indirect injection chamber]]
{{Main|Indirect injection}}
An indirect diesel injection system (IDI) engine delivers fuel into a small chamber called a swirl chamber, precombustion chamber, pre chamber or ante-chamber, which is connected to the cylinder by a narrow air passage. Generally the goal of the pre chamber is to create increased [[turbulence]] for better air / fuel mixing. This system also allows for a smoother, quieter running engine, and because fuel mixing is assisted by turbulence, [[injector]] pressures can be lower. Most IDI systems use a single orifice injector. The pre-chamber has the disadvantage of lowering efficiency due to increased heat loss to the engine's cooling system, restricting the combustion burn, thus reducing the efficiency by 5–10%. IDI engines are also more difficult to start and usually require the use of glow plugs. IDI engines may be cheaper to build but generally require a higher compression ratio than the DI counterpart. IDI also makes it easier to produce smooth, quieter running engines with a simple mechanical injection system since exact injection timing is not as critical. Most modern automotive engines are DI which have the benefits of greater efficiency and easier starting; however, IDI engines can still be found in the many ATV and small diesel applications.<ref name="Dieselhub" /> Indirect injected diesel engines use pintle-type fuel injectors.<ref name="Reif_2014_140" />

=== Air-blast injection ===
{{Main|Air-blast injection}}
[[File:Stationärdieselmotor 1915.jpg|thumb|right|Typical early 20th century air-blast injected diesel engine, rated at 59&nbsp;kW]]

Early diesel engines injected fuel with the assistance of compressed air, which atomised the fuel and forced it into the engine through a nozzle (a similar principle to an aerosol spray). The nozzle opening was closed by a [[Needle valve|pin valve]] actuated by the [[camshaft]]. Although the engine was also required to drive an air compressor used for air-blast injection, the efficiency was nonetheless better than other combustion engines of the time.<ref name="Mau_1984_7" /> However the system was heavy and it was slow to react to changing torque demands, making it unsuitable for road vehicles.<ref name="Merker_2014_381" />

=== Unit injectors ===
{{Main|Unit Injector}}
A ''unit injector'' system, also known as "Pumpe-Düse" (''pump-nozzle'' in German) combines the injector and fuel pump into a single component, which is positioned above each cylinder. This eliminates the high-pressure fuel lines and achieves a more consistent injection. Under full load, the injection pressure can reach up to 220&nbsp;MPa.<ref name="Reif Springer Fachmedien Wiesbaden p. 393">{{Cite book |last1=Reif |first1=Konrad |title=Dieselmotor-Management Systeme, Komponenten, Steuerung und Regelung |last2=Springer Fachmedien Wiesbaden |date=2020 |isbn=978-3-658-25072-0 |publication-place=Wiesbaden |page=393 |language=de |oclc=1156847338}}</ref> Unit injectors are operated by a [[Cam (mechanism)|cam]] and the quantity of fuel injected is controlled either mechanically (by a rack or lever) or electronically.

Due to increased performance requirements, unit injectors have been largely replaced by [[common rail]] injection systems.<ref name="Tschöke_2018_295" />

==Diesel engine particularities==

===Mass===
The average diesel engine has a poorer power-to-mass ratio than an equivalent petrol engine. The lower engine speeds (RPM) of typical diesel engines results in a lower [[Power (physics)|power]] output.<ref name="Braess_2012_225" /> Also, the mass of a diesel engine is typically higher, since the higher operating pressure inside the combustion chamber increases the internal forces, which requires stronger (and therefore heavier) parts to withstand these forces.<ref name="Schreiner_2014_22" />

=== Noise ("diesel clatter") ===
[[File:AKD 112 Z.webm|thumb|Engine noise of a 1950s [[MWM AKD 112 Z]] two-cylinder diesel engine at idle]]
[[File:Volvo Penta Motorljud.ogg|thumb|Volvo Penta 6-cylinder diesel engine sound.]]
The distinctive noise of a diesel engine, particularly at idling speeds, is sometimes called "diesel clatter". This noise is largely caused by the sudden ignition of the diesel fuel when injected into the combustion chamber, which causes a pressure wave that sounds like knocking.

Engine designers can reduce diesel clatter through: indirect injection; pilot or pre-injection;<ref name="Böge_2017_1150" /> injection timing; injection rate; compression ratio; turbo boost; and [[exhaust gas recirculation]] (EGR).<ref name="EngTips" /> Common rail diesel injection systems permit multiple injection events as an aid to noise reduction. Through measures such as these, diesel clatter noise is greatly reduced in modern engines. Diesel fuels with a higher [[Cetane number|cetane rating]] are more likely to ignite and hence reduce diesel clatter.<ref name="Comb in IC" />

===Cold weather starting===
In warmer climates, diesel engines do not require any starting aid (aside from the [[Starter (engine)|starter motor]]). However, many diesel engines include some form of preheating for the combustion chamber, to assist starting in cold conditions. Engines with a displacement of less than 1&nbsp;litre per cylinder usually have [[Glow plug (diesel engine)|glowplugs]], whilst larger heavy-duty engines have [[flame-start system]]s.<ref name="Reif_2014_136" /> The minimum starting temperature that allows starting without pre-heating is 40&nbsp;°C (104&nbsp;°F) for precombustion chamber engines, 20&nbsp;°C (68&nbsp;°F) for swirl chamber engines, and 0&nbsp;°C (32&nbsp;°F) for direct injected engines.

In the past, a wider variety of cold-start methods were used. Some engines, such as [[Detroit Diesel]] engines used{{When|date=September 2010}} a system to introduce small amounts of [[Diethyl ether|ether]] into the inlet manifold to start combustion.<ref name="FreeLib_1995" /> Instead of glowplugs, some diesel engines are equipped with starting aid systems that change valve timing. The simplest way this can be done is with a decompression lever. Activating the decompression lever locks the outlet valves in a slight down position, resulting in the engine not having any compression and thus allowing for turning the crankshaft over with significantly less resistance. When the crankshaft reaches a higher speed, flipping the decompression lever back into its normal position will abruptly re-activate the outlet valves, resulting in compression − the flywheel's [[mass moment of inertia]] then starts the engine.<ref name="Hawks_73" /> Other diesel engines, such as the precombustion chamber engine XII Jv 170/240 made by Ganz & Co., have a valve timing changing system that is operated by adjusting the inlet valve camshaft, moving it into a slight "late" position. This will make the inlet valves open with a delay, forcing the inlet air to heat up when entering the combustion chamber.<ref name="Kremser_1942_190" />

=== Supercharging & turbocharging ===
{{see also|Turbo-diesel}}
[[Forced induction]], especially turbocharging is commonly used on diesel engines because it greatly increases efficiency and torque output.<ref name="Reif_2014_41" /> Diesel engines are well suited for forced induction setups due to their operating principle which is characterised by wide ignition limits<ref name="Pischinger_2016_348" /> and the absence of fuel during the compression stroke. Therefore, knocking, pre-ignition or detonation cannot occur, and a lean mixture caused by excess supercharging air inside the combustion chamber does not negatively affect combustion.<ref name="Reif_2017_16" />

==Major manufacturers==
{{div col|colwidth=30em}}
* {{lwc|MTU Friedrichshafen|MTU|property=P17}}
* {{lwc|MAN Diesel|MAN|property=P17}}
* {{lwc|Wärtsilä|property=P17}}
* {{lwc|Rolls-Royce Power Systems|property=P17}}
* {{lwc|Siemens|property=P17}}
* [[Kolomna Locomotive Works|Kolomna]] KDZ [[Transmashholding|TMH]] [[Bryansk Machine-Building Plant|BMZ]] and {{lwc|Ural Diesel Engine Plant|UDMZ|property=P17}}
* [[General Electric]] {{lwc|GE Transportation|property=P17}}
* {{lwc|Volvo Penta|property=P17}}
* {{lwc|Sulzer (manufacturer)|Sulzer|property=P17}}
* {{lwc|Doosan Heavy Industries & Construction|Doosan|property=P17}} Doosan infracore, Doosan Marine
* {{lwc|Yaroslavl Motor Plant|YaMZ|property=P17}} [[AvtoVAZ|VAZ]], [[Kingisepp Machinery Plant|KMZ]] - RD Nevsky, [[Sinara Transport Machines|STM]] [[GAZ]] [[Voronezh Mechanical Plant|VMZ]] [[Volga Motor Plant Mamynykh|VMZ]]
* {{lwc|Mitsubishi Heavy Industries|Mitsubishi|property=P17}}, Mitsui Mazda IHI Kawasaki Honda Suzuki Subaru Isuzu Nissan plus others
* {{lwc|Daihatsu Infinearth Manufacturing Company|property=P17}}, formerly, Daihatsu Diesel Manufacturing Company
* {{lwc|Caterpillar Energy Solutions|Caterpillar|property=P17}}
* {{lwc|Cummins|property=P17}}
* [[AO Zvezda]] and {{lwc|Zvezda M503|Zvezda Energetika|property=P17}}
* {{lwc|Bergen Engines|property=P17}} 
* MaK Deutz AG MWM 
* {{lwc|BMW|property=P17}} 
* {{lwc|Volkswagen|VW|property=P17}}
* {{lwc|MAPNA|property=P17}} 
* {{lwc|BHEL|property=P17}} 
* {{lwc|DESA company|DESA|property=P17}}
* {{lwc|Steyr Motors GmbH|property=P17}}
* {{lwc|Iran Khodro Diesel|property=P17}}
* {{lwc|Isotta Fraschini|property=P17}}
* {{lwc|Electro-Motive Diesel|EMD|property=P17}} 
* {{lwc|Fairbanks-Morse|Fairbanks Morse|property=P17}}
* Shanxi 
* {{lwc|Henan Diesel Engine Industry Company|Henan Diesel|property=P17}} 
* {{lwc|Shaanxi Diesel Engine Heavy Industry|SDM|property=P17}}
{{div col end}}

==Fuel and fluid characteristics==
{{Main|Diesel fuel}}

Diesel engines can combust a huge variety of fuels, including several fuel oils that have advantages over fuels such as petrol. These advantages include:
* Low fuel costs, as fuel oils are relatively cheap
* Good lubrication properties
* High energy density
* Low risk of catching fire, as they do not form a flammable vapour
* [[Biodiesel]] is an easily synthesised, non-petroleum-based fuel (through [[transesterification]]) which can run directly in many diesel engines, while gasoline engines either need adaptation to run [[synthetic fuel]]s or else use them as an additive to gasoline (e.g., [[ethanol]] added to [[gasohol]]).
In diesel engines, a mechanical injector system atomizes the fuel directly into the combustion chamber (as opposed to a [[Aspirator (pump)|Venturi jet]] in a carburetor, or a [[Fuel injection|fuel injector]] in a manifold injection system atomizing fuel into the intake manifold or intake runners as in a petrol engine). Because only air is inducted into the cylinder in a diesel engine, the compression ratio can be much higher as there is no risk of pre-ignition provided the injection process is accurately timed.<ref name="Reif_2017_16" /> This means that cylinder temperatures are much higher in a diesel engine than a petrol engine, allowing less volatile fuels to be used.

[[File:MAN 630 L2A 03.jpg|thumb|The MAN 630's [[M-System]] diesel engine is a petrol engine (designed to run on NATO F 46/F 50 petrol), but it also runs on jet fuel, (NATO F 40/F 44), kerosene, (NATO F 58), and diesel engine fuel (NATO F 54/F 75)]]

Therefore, diesel engines can operate on a huge variety of different fuels. In general, fuel for diesel engines should have a proper [[viscosity]], so that the [[injection pump]] can pump the fuel to the injection nozzles without causing damage to itself or corrosion of the fuel line. At injection, the fuel should form a good fuel spray, and it should not have a coking effect upon the injection nozzles. To ensure proper engine starting and smooth operation, the fuel should be willing to ignite and hence not cause a high ignition delay, (this means that the fuel should have a high [[cetane number]]). Diesel fuel should also have a high [[lower heating value]].<ref name="vPhilippovich_1939_41" />

Inline mechanical injector pumps generally tolerate poor-quality or bio-fuels better than distributor-type pumps. Also, indirect injection engines generally run more satisfactorily on fuels with a high ignition delay (for instance, petrol) than direct injection engines.<ref name="vPhilippovich_1939_45" /> This is partly because an indirect injection engine has a much greater 'swirl' effect, improving vaporisation and combustion of fuel, and because (in the case of vegetable oil-type fuels) [[lipid]] depositions can condense on the cylinder walls of a direct-injection engine if combustion temperatures are too low (such as starting the engine from cold). Direct-injected engines with an [[M-System|MAN centre sphere combustion chamber]] rely on fuel condensing on the combustion chamber walls. The fuel starts vaporising only after ignition sets in, and it burns relatively smoothly. Therefore, such engines also tolerate fuels with poor ignition delay characteristics, and, in general, they can operate on petrol rated 86 [[Octane rating#Research Octane Number (RON)|RON]].<ref name="MAN_438" />

===Fuel types===
In his 1893 work ''[[Theory and Construction of a Rational Heat Motor]]'', Rudolf Diesel considers using [[coal dust]] as fuel for the diesel engine. However, Diesel just ''considered'' using coal dust (as well as liquid fuels and gas); his actual engine was designed to operate on [[petroleum]], which was soon replaced with regular [[petrol]] and kerosene for further testing purposes, as petroleum proved to be too viscous.<ref name="Diesel_1913_107" /> In addition to kerosene and petrol, Diesel's engine could also operate on [[ligroin]].<ref name="Diesel_1913_110" />

Before diesel engine fuel was standardised, fuels such as [[petrol]], [[kerosene]], [[gas oil]], [[vegetable oil]] and [[Lubricant#Mineral oil|mineral oil]], as well as mixtures of these fuels, were used.<ref name="MAN_436" /> Typical fuels specifically intended to be used for diesel engines were [[petroleum distillate]]s and [[creosote|coal-tar distillates]] such as the following; these fuels have specific lower heating values of:
* Diesel oil: 10,200&nbsp;kcal·kg<sup>−1</sup> (42.7&nbsp;MJ·kg<sup>−1</sup>) up to 10,250&nbsp;kcal·kg<sup>−1</sup> (42.9&nbsp;MJ·kg<sup>−1</sup>)
* Heating oil: 10,000&nbsp;kcal·kg<sup>−1</sup> (41.8&nbsp;MJ·kg<sup>−1</sup>) up to 10,200&nbsp;kcal·kg<sup>−1</sup> (42.7&nbsp;MJ·kg<sup>−1</sup>)
* Coal-tar [[creosote]]: 9,150&nbsp;kcal·kg<sup>−1</sup> (38.3&nbsp;MJ·kg<sup>−1</sup>) up to 9,250&nbsp;kcal·kg<sup>−1</sup> (38.7&nbsp;MJ·kg<sup>−1</sup>)
* [[Kerosene]]: up to 10,400&nbsp;kcal·kg<sup>−1</sup> (43.5&nbsp;MJ·kg<sup>−1</sup>)

''Source:''<ref name="vPhilippovich_1939_43" />

The first diesel fuel standards were the [[DIN 51601]], [[VTL 9140-001]], and [[NATO F 54]], which appeared after World War II.<ref name="MAN_436" /> The modern European [[EN 590]] [[diesel fuel]] standard was established in May 1993; the modern version of the NATO F 54 standard is mostly identical with it. The DIN 51628 biodiesel standard was rendered obsolete by the 2009 version of the EN 590; FAME biodiesel conforms to the [[EN 14214]] standard. Watercraft diesel engines usually operate on diesel engine fuel that conforms to the [[ISO 8217]] standard ([[Bunker C]]). Also, some diesel engines can operate on [[Fuel gas|gas]]ses (such as [[LNG]]).<ref name="Schwarz_2012_102" />

===Modern diesel fuel properties===
{|class="wikitable"
|+Modern diesel fuel properties<ref name="Reif_2014_53" />
|-
|
!EN 590 (as of 2009)
!EN 14214 (as of 2010)
|-
!Ignition performance
| ≥ 51 [[Cetane number|CN]]
| ≥ 51 CN
|-
!Density at 15&nbsp;°C
| 820...845&nbsp;kg·m<sup>−3</sup>
| 860...900&nbsp;kg·m<sup>−3</sup>
|-
!Sulfur content
| ≤10&nbsp;mg·kg<sup>−1</sup>
| ≤10&nbsp;mg·kg<sup>−1</sup>
|-
!Water content
| ≤200&nbsp;mg·kg<sup>−1</sup>
| ≤500&nbsp;mg·kg<sup>−1</sup>
|-
!Lubricity
| 460&nbsp;μm
| 460&nbsp;μm
|-
!Viscosity at 40&nbsp;°C
| 2.0...4.5&nbsp;mm<sup>2</sup>·s<sup>−1</sup>
| 3.5...5.0&nbsp;mm<sup>2</sup>·s<sup>−1</sup>
|-
![[Fatty acid methyl ester|FAME]] content
| ≤7.0%
| ≥96.5%
|-
!Molar H/C ratio
| –
| 1.69
|-
!Lower heating value
| –
| 37.1&nbsp;MJ·kg<sup>−1</sup>
|}

===Gelling===
DIN 51601 diesel fuel was prone to ''waxing'' or ''gelling'' in cold weather; both are terms for the solidification of diesel oil into a partially crystalline state. The crystals build up in the fuel system (especially in fuel filters), eventually starving the engine of fuel and causing it to stop running.<ref name="vB_2017_1018" /> Low-output electric heaters in [[fuel tank]]s and around fuel lines were used to solve this problem. Also, most engines have a ''spill return'' system, by which any excess fuel from the injector pump and injectors is returned to the fuel tank. Once the engine has warmed, returning warm fuel prevents waxing in the tank. Before direct injection diesel engines, some manufacturers, such as BMW, recommended mixing up to 30% petrol in with the diesel by fuelling diesel cars with petrol to prevent the fuel from gelling when the temperatures dropped below −15&nbsp;°C.<ref name="BMW_1985" />

==Safety==

===Fuel flammability===

Diesel fuel is less [[flammability|flammable]] than petrol, because its flash point is 55&nbsp;°C,<ref name="vB_2017_1018" /><ref name="vPhilippovich_1939_42" /> leading to a lower risk of fire caused by fuel in a vehicle equipped with a diesel engine.

Diesel fuel can create an explosive air/vapour mix under the right conditions. However, compared with petrol, it is less prone due to its lower [[vapor pressure|vapour pressure]], which is an indication of evaporation rate. The Material Safety Data Sheet<ref name="Ultra low sulfur diesel" /> for ultra-low sulfur diesel fuel indicates a vapour explosion hazard for diesel fuel indoors, outdoors, or in sewers.

===Cancer===
[[Diesel exhaust]] has been classified as an [[List of IARC Group 1 carcinogens|IARC Group 1 carcinogen]]. It causes [[lung cancer]] and is associated with an increased risk for [[bladder cancer]].<ref name="PRDEE">{{Cite web |title=IARC: Diesel Engine Exhaust Carcinogenic |url=https://www.iarc.fr/wp-content/uploads/2018/07/pr213_E.pdf/ |url-status=dead |archive-url=https://web.archive.org/web/20120912080023/http://press.iarc.fr/pr213_E.pdf |archive-date=September 12, 2012 |access-date=June 12, 2012 |publisher=International Agency for Research on Cancer (IARC) |format=Press release |quote=June 12, 2012 – After a week-long meeting of international experts, the International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO), today classified diesel engine exhaust as carcinogenic to humans (Group 1), based on sufficient evidence that exposure is associated with an increased risk for bladder cancer |df=mdy}}</ref>

===Engine runaway (uncontrollable overspeeding)===
See [[diesel engine runaway]].

==Applications==
The characteristics of diesel have different advantages for different applications.

===Passenger cars===
{{See also|History of the diesel car}}
Diesel engines have long been popular in bigger cars and have been used in smaller cars such as [[supermini]]s in Europe since the 1980s. They were popular in larger cars earlier, as the weight and cost penalties were less noticeable.<ref name="AG125">{{Cite journal |last=Pirotte |first=Marcel |date=1984-07-05 |title=Gedetailleerde Test: Citroën BX19 TRD |trans-title=Detailed Test |journal=De AutoGids |language=nl-be |location=Brussels, Belgium |volume=5 |page=6 |ref=AG125 |number=125}}</ref> Smooth operation as well as high low-end torque are deemed important for passenger cars and small commercial vehicles. The introduction of electronically controlled fuel injection significantly improved the smooth torque generation, and starting in the early 1990s, car manufacturers began offering their high-end luxury vehicles with diesel engines. Passenger car diesel engines usually have between three and twelve cylinders, and a displacement ranging from 0.8 to 6.0 litres. Modern powerplants are usually turbocharged and have direct injection.<ref name="Reif_2014_11" />

Diesel engines do not suffer from intake-air throttling, resulting in very low fuel consumption especially at low partial load<ref name="Reif_2014_23" /> (for instance: driving at city speeds). One fifth of all passenger cars worldwide have diesel engines, with many of them being in Europe, where approximately 47% of all passenger cars are diesel-powered.<ref name="Tschöke_2018_1000" /> [[Daimler-Benz]] in conjunction with [[Robert Bosch GmbH]] produced diesel-powered passenger cars starting in 1936.<ref name="Tschöke_2018_10" /> The popularity of diesel-powered passenger cars in markets such as India, South Korea and Japan is increasing (as of 2018).<ref name="Tschöke_2018_981" />

===Commercial vehicles and lorries===
{{Chart|definition=Lifespan of Mercedes-Benz diesel engines.chart|data=Lifespan of Mercedes-Benz diesel engines.tab|width=400px|caption=Source: <ref name="Merker_2014_264" />;|align=right|thumb}}

In 1893, Rudolf Diesel suggested that the diesel engine could possibly power "wagons" (lorries).<ref name="Diesel_1893_91" /> The first lorries with diesel engines were brought to market in 1924.<ref name="Tschöke_2018_10" />

Modern diesel engines for lorries have to be both extremely reliable and very fuel efficient. Common-rail direct injection, turbocharging and four valves per cylinder are standard. Displacements range from 4.5 to 15.5 litres, with [[Power-to-weight ratio|power-to-mass ratios]] of 2.5–3.5&nbsp;kg·kW<sup>−1</sup> for heavy duty and 2.0–3.0&nbsp;kg·kW<sup>−1</sup> for medium duty engines. [[V engine|V6 and V8 engines]] used to be common, due to the relatively low engine mass the V configuration provides. Recently, the V configuration has been abandoned in favour of straight engines. These engines are usually straight-6 for heavy and medium duties and straight-4 for medium duty. Their [[undersquare]] design causes lower overall piston speeds which results in increased lifespan of up to {{convert| 1200000| km|mi}}.<ref name="Merker_2014_48" /> Compared with 1970s diesel engines, the expected lifespan of modern lorry diesel engines has more than doubled.<ref name="Merker_2014_264" />

===Railroad rolling stock===
Diesel engines for locomotives are built for continuous operation between refuelings and may need to be designed to use poor quality fuel in some circumstances.<ref name="Reif_2014_12" /> Some locomotives use two-stroke diesel engines.<ref name="Merker_2014_284" /> Diesel engines have replaced [[Steam locomotive|steam engine]]s on all non-electrified railroads in the world. The first [[diesel locomotive]]s appeared in 1913,<ref name="Tschöke_2018_10" /> and [[diesel multiple units]] soon after. Nearly all modern diesel locomotives are more correctly known as [[diesel–electric locomotive]]s because they use an electric transmission: the diesel engine drives an electric generator which powers electric traction motors.<ref name="vB_2017_1289" /> While [[electric locomotive]]s have replaced the diesel locomotive for passenger services in many areas diesel traction is widely used for cargo-hauling [[freight train]]s and on tracks where electrification is not economically viable.

In the 1940s, road vehicle diesel engines with power outputs of {{convert|150|-|200|PS|kW hp}} were considered reasonable for DMUs. Commonly, regular truck powerplants were used. The height of these engines had to be less than {{convert|1|m}} to allow underfloor installation. Usually, the engine was mated with a pneumatically operated mechanical gearbox, due to the low size, mass, and production costs of this design. Some DMUs used hydraulic torque converters instead. Diesel–electric transmission was not suitable for such small engines.<ref name="Kremser_1942_22" /> In the 1930s, the [[Deutsche Reichsbahn]] standardised its first DMU engine. It was a {{convert|30.3|litre|cuin}}, 12-cylinder boxer unit, producing {{convert|275|PS|kW hp}}. Several German manufacturers produced engines according to this standard.<ref name="Kremser_1942_23" />

===Watercraft===
[[File:8 cylinder Burmeister & Wain Diesel engine for MS Glenapp 1920.png|thumb|One of the eight-cylinder 3200 I.H.P. Harland and Wolff – Burmeister & Wain diesel engines installed in the motorship ''Glenapp''. This was the highest powered diesel engine yet (1920) installed in a ship. Note man standing lower right for size comparison.]]
[[File:InleHandCrank.webm|thumb|right|Hand-cranking a boat diesel motor in [[Inle Lake]] ([[Myanmar]])]]
The requirements for marine diesel engines vary, depending on the application. For military use and medium-size boats, medium-speed four-stroke diesel engines are most suitable. These engines usually have up to 24 cylinders and come with power outputs in the one-digit Megawatt region.<ref name="Reif_2014_12" /> Small boats may use lorry diesel engines. Large ships use extremely efficient, low-speed two-stroke diesel engines. They can reach efficiencies of up to 55%. Unlike most regular diesel engines, two-stroke watercraft engines use highly viscous [[fuel oil]].<ref name="Reif_2014_13" /> Submarines are usually diesel–electric.<ref name="vB_2017_1289" />

The first diesel engines for ships were made by A. B. Diesels Motorer Stockholm in 1903. These engines were three-cylinder units of 120&nbsp;PS (88&nbsp;kW) and four-cylinder units of 180&nbsp;PS (132&nbsp;kW) and used for Russian ships. In World War I, especially submarine diesel engine development advanced quickly. By the end of the War, double acting piston two-stroke engines with up to 12,200&nbsp;PS (9&nbsp;MW) had been made for marine use.<ref name="Mau_1984_9_11" />

===Aviation===
{{Main|Aircraft diesel engine}}

====Early====
Diesel engines had been used in aircraft before World War II, for instance, in the rigid airship ''[[LZ 129 Hindenburg]],'' which was powered by four [[Daimler-Benz DB 602]] diesel engines,<ref>Kyrill von Gersdorff, Kurt Grasmann: ''Flugmotoren und Strahltriebwerke: Entwicklungsgeschichte der deutschen Luftfahrtantriebe von den Anfängen bis zu den internationalen Gemeinschaftsentwicklungen'', Bernard & Graefe, 1985, {{ISBN|9783763752836}}, p. 14</ref> or in several Junkers aircraft, which had [[Junkers Jumo 205|Jumo 205]] engines installed.<ref name="Reif_2012_103" />

In 1929, in the United States, the [[Packard Motor Company]] developed America's first aircraft diesel engine, the [[Packard DR-980]]—an air-cooled, 9-cylinder [[radial engine]]. They installed it in various aircraft of the era—some of which  were used in record-breaking distance or endurance flights,<ref name="flies_700_miles_1929_05_15_nytimes_com">[https://www.nytimes.com/1929/05/15/archives/flies-700-miles-fuel-cost-468-dieselmotored-packard-plane-goes-from.html "FLIES 700 MILES; FUEL COST $4.68; Diesel-Motored Packard Plane Goes From Michigan to Langley Field in Under Seven Hours. ENGINE HAS NINE CYLINDERS Oil Burner Is Exhibited Before Aviation Leaders, Met for Conference. Woolson Reports on Flight. Packard Motor Stocks Rise,"] May 15, 1929, ''[[New York Times]],'' retrieved December 5, 2022</ref><ref name="packard_2019_05_24_dieselworldmag_com">[https://www.dieselworldmag.com/diesel-engines/first-in-flight/ "The Packard DR-980 Radial Aircraft Diesel"] "First in Flight," "Diesel Engines," May 24, 2019, ''Diesel World'' magazine, retrieved December 5, 2022</ref><ref name="packard_diesel_buhl_earlyaviators_com">[https://www.earlyaviators.com/pimage26.htm "Packard-Diesel Powered Buhl Air Sedan, 1930"] (reproductions of early media articles and photos, with added information), ''Early Birds of Aviation,'' retrieved December 5, 2022</ref><ref name=enginehistory>[http://www.enginehistory.org/Diesels/CH1.pdf Aircraft Engine Historical Society – Diesels] {{webarchive|url=https://web.archive.org/web/20120212213152/http://www.enginehistory.org/Diesels/CH1.pdf |date=2012-02-12 }} Retrieved: 30 January 2009</ref> and in the first successful demonstration of ground-to-air radiophone communications (voice radio having been previously unintelligible in aircraft equipped with spark-ignition engines, due to [[electromagnetic interference]]).<ref name="packard_2019_05_24_dieselworldmag_com" /><ref name="packard_diesel_buhl_earlyaviators_com" /> Additional advantages cited, at the time, included a lower risk of post-crash fire, and superior performance at high altitudes.<ref name="packard_2019_05_24_dieselworldmag_com" />

On March 6, 1930, the engine received an [[Type Certificate|Approved Type Certificate]]—first ever for an aircraft diesel engine—from the [[U.S. Department of Commerce]].<ref name="diesel_aviation_engines_1940_enginehistory_org">Wilkinson, Paul H.: [https://www.enginehistory.org/Piston/Diesels/diesels.shtml "Diesel Aviation Engines,"] 1940, reproduced at Aviation Engine Historical Society, retrieved December 5, 2022</ref> However, noxious exhaust fumes, cold-start and vibration problems, engine structural failures, the death of its developer, and the industrial economic contraction of the [[Great Depression]], combined to kill the program.<ref name="packard_2019_05_24_dieselworldmag_com" />

====Modern====
From then, until the late 1970s, there had not been many applications of the diesel engine in aircraft. In 1978, [[Piper Cherokee]] co-designer Karl H. Bergey argued that "the likelihood of a general aviation diesel in the near future is remote."<ref>Karl H. Bergey: ''[https://books.google.com/books?id=av85AQAAMAAJ Assessment of New Technology for General Aviation Aircraft]'', Report for U.S. Department of Transportation, September 1978, p. 19</ref>

However, with the [[1970s energy crisis]] and [[environmental movement]], and resulting pressures for greater fuel economy, reduced carbon and lead in the atmosphere, and other issues, there was a resurgence of interest in diesel engines for aircraft. High-compression piston aircraft engines that run on aviation gasoline ("[[avgas]]") generally require the addition of toxic [[Tetraethyl lead]] to avgas, to avoid engine [[Engine knocking|pre-ignition and detonation]]; but diesel engines do not require leaded fuel. Also, [[biodiesel]] can, theoretically, provide a net reduction in atmospheric carbon compared to avgas. For these reasons, the [[general aviation]] community has begun to fear the possible banning or discontinuance of leaded avgas.<ref name="inside_2018_08_01_flyingmag_com" /><ref name="congressman_2012_10_24_generalaviationnews">Wood, Janice (editor): [https://generalaviationnews.com/2012/10/24/congressman-calls-on-faa-to-expand-use-of-unleaded-fuel/ Congressman urges FAA to expand use of existing unleaded fuel,"] October 24, 2012, ''General Aviation News,'' retrieved December 6, 2022</ref><ref name="hanke_2006_07_21_g_a_news">[https://www.linkedin.com/in/kurt-hanke-6bb24ab Hanke, Kurt F., engineer] ([https://www.turbocraft.com/ Turbocraft, Inc.]), [https://generalaviationnews.com/2006/07/21/diesels-are-the-way-for-ga-to-go/ "Diesels are the Way for GA to Go,"] July 21, 2006, ''Ge eral Aviation News,'' retrieved December 6, 2022</ref><ref name="biodiesel_basics_2003_energy_gov">{{cite journal|title=Biodiesel – Just the Basics|version=Final|year=2003|publisher=United States Department of Energy|url=http://www.eere.energy.gov/vehiclesandfuels/pdfs/basics/jtb_biodiesel.pdf|access-date=2007-08-24|url-status=dead|archive-url=https://web.archive.org/web/20070918122719/http://www1.eere.energy.gov/vehiclesandfuels/pdfs/basics/jtb_biodiesel.pdf|archive-date=2007-09-18}}</ref>

Additionally, avgas is a specialty fuel in very low (and declining) demand, compared to other fuels, and its makers are susceptible to costly aviation-crash lawsuits, reducing refiners' interest in producing it.  Outside the United States, avgas has already become increasingly difficult to find at airports (and generally), than less-expensive, diesel-compatible fuels like Jet-A and other [[jet fuel]]s.<ref name="inside_2018_08_01_flyingmag_com" /><ref name="congressman_2012_10_24_generalaviationnews" /><ref name="hanke_2006_07_21_g_a_news" /><ref name="biodiesel_basics_2003_energy_gov" />

By the late 1990s / early 2000s, diesel engines were beginning to appear in light aircraft.  Most notably, [[Thielert|Frank Thielert and his Austrian engine enterprise]], began developing diesel engines to replace the {{convert|100|hp|kW}} - {{convert|350|hp|kW}} gasoline/piston engines in common light aircraft use.<ref name="powerplant_ch7_phak_faa_gov">[https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak/media/09_phak_ch7.pdf "Powerplant"], in Chapter 7: "Aircraft Systems," ''Pilot's Handbook of Aeronautical Knowledge,'' [[Federal Aviation Administration]], retrieved December 5, 2022</ref> First successful application of the Theilerts to production aircraft was in the [[Diamond DA42 Twin Star]] light twin, which exhibited exceptional fuel efficiency surpassing anything in its class,<ref name="inside_2018_08_01_flyingmag_com" /><ref name="diamond_2020_12_30_avweb_com" /><ref name="diamond_da42_2004_05_12_flightglobal_com">Collins, Peter: [https://www.flightglobal.com/flight-test-diamond-aircraft-da42-sparkling-performer/55396.article "FLIGHT TEST: Diamond Aircraft DA42 - Sparkling performer,"] July 12, 2004, ''[[FlightGLobal]]'' retrieved December 5, 2022</ref> and its single-engined predecessor, the [[Diamond DA40 Diamond Star]].<ref name="inside_2018_08_01_flyingmag_com" /><ref name="diamond_2020_12_30_avweb_com" /><ref name="powerplant_ch7_phak_faa_gov" />

In subsequent years, several other companies have developed aircraft diesel engines, or have begun to<ref name="powerplant_ch7_phak_faa_gov" />—most notably [[Continental Aerospace Technologies]] which, by 2018, was reporting it had sold over 5,000 such engines worldwide.<ref name="inside_2018_08_01_flyingmag_com" /><ref name="diamond_2020_12_30_avweb_com" /><ref name="certified_jet_a_engines_continental_aero">[https://www.continental.aero/diesel/diesel-engines.aspx "Certified Jet-A Engines,"], [[Continental Aerospace Technologies]], retrieved December 5, 2022</ref>

The United States' [[Federal Aviation Administration]] has reported that "by 2007, various jet-fueled piston aircraft had logged well over 600,000 hours of service".<ref name="powerplant_ch7_phak_faa_gov" /> In early 2019, [[Aircraft Owners and Pilots Association|AOPA]] reported that a diesel engine model for general aviation aircraft is "approaching the finish line."<ref name="eps_update_2019_01_23_aopa_org">[https://www.aopa.org/news-and-media/all-news/2019/january/23/eps-gives-certification-update-on-diesel-engine ''EPS gives certification update on diesel engine,''], January 23, 2019, [[Aircraft Owners and Pilots Association|AOPA]]. Retrieved November 1, 2019.</ref> By late 2022, Continental was reporting that its "Jet-A" fueled engines had exceeded "2,000... in operation today," with over "9 million hours," and were being "specified by major OEMs" for [[Cessna Aircraft|Cessna]], [[Piper Aircraft|Piper]],  [[Diamond Aircraft|Diamond]], [[Mooney Aircraft|Mooney]], [[Tecnam Aircraft|Tecnam]], [[Glasair]] and [[Avions Pierre Robin|Robin]] aircraft.<ref name="certified_jet_a_engines_continental_aero" />

In recent years (2016), diesel engines have also found use in unmanned aircraft (UAV), due to their reliability, durability, and low fuel consumption.<ref name="knock_criteria_2017_meininger_doi_org">Rik D Meininger et al.: "Knock criteria for aviation diesel engines", ''International Journal of Engine Research,'' Vol 18, Issue 7, 2017, [https://doi.org/10.1177/1468087416669882 doi/10.1177]</ref><ref name="Arnews2005">{{cite news |title=Army awards 'Warrior' long-range UAV contract |date=2005-08-05 |publisher=Army News Service |url=http://www4.army.mil/news/article.php?story=7722 |url-status=dead |archive-url=https://web.archive.org/web/20070102153829/http://www4.army.mil/news/article.php?story=7722 |archive-date=2 January 2007  }}</ref><ref name="defenseupdate2006">{{cite news |title= ERMP Extended-Range Multi-Purpose UAV |publisher= Defense Update |date= 2006-11-01 |url= http://www.defense-update.com/products/e/ermpUAV.htm |access-date= 11 May 2007 |archive-url= https://web.archive.org/web/20080513125340/http://www.defense-update.com/products/e/ermpUAV.htm |archive-date= 13 May 2008 |url-status= dead |df= dmy-all }}</ref>

===Non-road diesel engines===
[[File:Porsche F 218.jpg|thumb|Air-cooled diesel engine of a 1959 Porsche 218]]

[[Non-road engine|Non-road diesel engines]] are commonly used for [[construction equipment]] and [[agricultural machinery]]. Fuel efficiency, reliability and ease of maintenance are very important for such engines, whilst high power output and quiet operation are negligible. Therefore, mechanically controlled fuel injection and air-cooling are still very common. The common power outputs of non-road diesel engines vary a lot, with the smallest units starting at 3&nbsp;kW, and the most powerful engines being heavy duty lorry engines.<ref name="Reif_2014_12" />

===Stationary diesel engines===
[[File:The National Archives UK - CO 1069-182-9.jpg|thumb|Three English Electric 7SRL diesel-alternator sets being installed at the Saateni Power Station; [[Zanzibar]], 1955]]

Stationary diesel engines are commonly used for electricity generation, but also for powering refrigerator compressors, or other types of compressors or pumps. Usually, these engines either run continuously with partial load, or intermittently with full load. Stationary diesel engines powering electric generators that put out an alternating current, usually operate with alternating load, but fixed rotational frequency. This is due to the mains' fixed frequency of either 50&nbsp;Hz (Europe), or 60&nbsp;Hz (United States). The engine's crankshaft rotational frequency is chosen so that the mains' frequency is a multiple of it. For practical reasons, this results in crankshaft rotational frequencies of either 25&nbsp;Hz (1500 per minute) or 30&nbsp;Hz (1800 per minute).<ref name="Tschöke_2018_1066" />

=== Diesel engines with a flexible crankshaft ===
Diesel engines with a flexible crankshaft refer to internal combustion engines where the crankshaft exhibits a degree of elasticity due to operational stresses, manufacturing tolerances, and material properties. Unlike a perfectly rigid crankshaft, a flexible one undergoes dynamic deformations due to cyclic combustion forces, inertial loads, and lubrication effects, which can lead to eccentric motion and vibrational displacement. This flexibility can impact engine performance by influencing bearing loads, lubrication film distribution, and mechanical wear, potentially reducing efficiency and lifespan. Advanced modeling techniques, such as Finite Element Analysis (FEA) and Multi-Body Dynamics (MBD), are used to predict and mitigate these effects, enabling better engine design, improved fuel efficiency, and enhanced durability. The flexibility of a crankshaft decreases the mass flow rate of air that goes into cylinders, resulting in an unfavorable higher rate of exhaust emissions like CO.<ref>{{Cite journal |last1=Elmoselhy |first1=Salah A. M. |last2=Faris |first2=Waleed F. |last3=Rakha |first3=Hesham A. |date=2021-02-26 |title=Validated Analytical Modeling of Diesel Engines Intake Manifold with a Flexible Crankshaft |journal=Energies |language=en |volume=14 |issue=5 |pages=1287 |doi=10.3390/en14051287 |doi-access=free |issn=1996-1073|hdl=10919/102459 |hdl-access=free }}</ref>

==Low heat rejection engines==
A special class of prototype internal combustion [[piston engine]]s has been developed over several decades with the goal of improving efficiency by reducing heat loss.<ref name="Papers on adiabatic engines" /> These engines are variously called adiabatic engines (due to better approximation of adiabatic expansion), low heat rejection engines, or high temperature engines.<ref name="Schwarz_1993" /> They are generally piston engines with combustion chamber parts lined with ceramic thermal barrier coatings.<ref name="BRYZIK_1993" /> Some make use of pistons and other parts made of titanium which has a low thermal conductivity<ref name="Danielson_1993" /> and density. Some designs are able to eliminate the use of a cooling system and associated parasitic losses altogether.<ref name="Nanlin_1993" /> Developing lubricants able to withstand the higher temperatures involved has been a major barrier to commercialization.<ref name="Kamo_1995" />

==Future developments==

In mid-2010s literature, main development goals for future diesel engines are described as improvements of exhaust emissions, reduction of fuel consumption, and increase of lifespan (2014).<ref name="Merker_2014_58" /><ref name="Reif_2014_11" /> It is said that the diesel engine, especially the diesel engine for commercial vehicles, will remain the most important vehicle powerplant until the mid-2030s. Editors assume that the complexity of the diesel engine will increase further (2014).<ref name="Merker_2014_273" /> Some editors expect a future convergency of diesel and [[Otto engine|Otto engines']] operating principles due to Otto engine development steps made towards [[homogeneous charge compression ignition]] (2017).<ref name="Stan_2017_252" />

==See also==
{{Div col}}
* [[Aircraft diesel engine]]
* [[Diesel locomotive]]
* [[Diesel automobile racing]]
* [[Diesel–electric transmission]]
* [[Diesel cycle]]
* [[Diesel exhaust]]
* [[DieselHouse]]
* [[Diesel generator]]
* [[Dieselisation]]
* [[History of the internal combustion engine]]
* [[Indirect injection]]
* [[Partially premixed combustion]]
* [[Reactivity controlled compression ignition]]
{{div col end}}

==References==
{{Reflist|30em
|refs=

;Van Basshuysen
<ref name="vB_2017_755">Richard van Basshuysen (ed.), Fred Schäfer (ed.): ''Handbuch Verbrennungsmotor: Grundlagen, Komponenten, Systeme, Perspektiven'', 8th edition, Springer, Wiesbaden 2017, {{ISBN|978-3-658-10901-1}}. p. 755</ref>
<ref name="vB_2017_1018">Richard van Basshuysen (ed.), Fred Schäfer (ed.): ''Handbuch Verbrennungsmotor: Grundlagen, Komponenten, Systeme, Perspektiven'', 8th edition, Springer, Wiesbaden 2017, {{ISBN|978-3-658-10901-1}}. p. 1018</ref>
<ref name="vB_2017_1289">Richard van Basshuysen (ed.), Fred Schäfer (ed.): ''Handbuch Verbrennungsmotor: Grundlagen, Komponenten, Systeme, Perspektiven'', 8th edition, Springer, Wiesbaden 2017, {{ISBN|978-3-658-10901-1}}. p. 1289</ref>

<ref name="vBasshuysen_2017_24">Richard van Basshuysen (ed.): ''Ottomotor mit Direkteinspritzung und Direkteinblasung: Ottokraftstoffe, Erdgas, Methan, Wasserstoff'', 4th edition, Springer, Wiesbaden, 2017. {{ISBN|978-3658122157}}. pp. 24, 25</ref>
<ref name="vBasshuysen_2017_141">Richard van Basshuysen (ed.): ''Ottomotor mit Direkteinspritzung und Direkteinblasung: Ottokraftstoffe, Erdgas, Methan, Wasserstoff'', 4th edition, Springer, Wiesbaden, 2017. {{ISBN|978-3658122157}}. p. 141</ref>

;Bosch 1993

;Böge 2017
<ref name="Böge_2017_1150">Alfred Böge, Wolfgang Böge (ed.): ''Handbuch Maschinenbau – Grundlagen und Anwendungen der Maschinenbau-Technik'', 23rd edition, Springer, Wiesbaden 2017, {{ISBN|978-3-658-12528-8}}, p. 1150</ref>

;Braess 2012
<ref name="Braess_2012_225">Hans-Hermann Braess (ed.), Ulrich Seiffert (ed.): Vieweg Handbuch Kraftfahrzeugtechnik, 6th edition, Springer, Wiesbaden 2012, {{ISBN|978-3-8348-8298-1}}. p. 225</ref>

;BMW 1985
<ref name="BMW_1985">BMW AG (ed.): [https://bmw-grouparchiv.de/research/media/9bddc3a9-90a1-4269-837c-b1775730d863/web BMW E28 owner's manual], 1985, section 4–20</ref>

;Bryzik 1993
<ref name="BRYZIK_1993">{{Cite book |last1=Bryzik |first1=Walter |title=SAE Technical Paper Series |last2=Schwarz |first2=Ernest |last3=Kamo |first3=Roy |last4=Woods |first4=Melvin |date=March 1, 1993 |volume=1 |chapter=Low Heat Rejection From High Output Ceramic Coated Diesel Engine and Its Impact on Future Design |article-number=931021 |doi=10.4271/931021 |chapter-url=http://papers.sae.org/931021/ |via=papers.sae.org}}</ref>

;Cole 2014
<ref name="Cole_2014_64">Lance Cole: ''Citroën – The Complete Story'', The Crowood Press, Ramsbury 2014, {{ISBN|978-1-84797-660-4}}. p. 64</ref>

;Cummins
<ref name="Cummins_1946">US Patent #2,408,298, filed April 1943, awarded Sept 24, 1946</ref>
<ref name="Cummins_1965">US Patent #3,220,392, filed June 4, 1962, granted Nov 30, 1965.</ref>

;Daimler 2009
<ref name="Daimler_2009">Daimler Media : [https://media.daimler.com/marsMediaSite/de/instance/ko/Vorkammer-Adieu-Im-Jahr-1964-kommen-erste-Direkteinspritzer-bei-Lkw-und-Bus.xhtml?oid=9913116 Vorkammer Adieu: Im Jahr 1964 kommen erste Direkteinspritzer bei Lkw und Bus], 12 Februar 2009, retrieved 22 February 2019.</ref>
<ref name="Daimler_2009_2">Daimler AG: ''[https://media.daimler.com/marsMediaSite/de/instance/ko/Geburt-einer-Legende-Die-1949-vorgestellte-Motorenbaureihe-300-ist-ein-grosser-Wurf.xhtml?oid=9914319 Die Geburt einer Legende: Die Baureihe 300 ist ein großer Wurf]'', 22 April 2009, retrieved 23 February 2019</ref>

;Danielson 1993
<ref name="Danielson_1993">{{Cite book |last1=Danielson |first1=Eugene |title=SAE Technical Paper Series |last2=Turner |first2=David |last3=Elwart |first3=Joseph |last4=Bryzik |first4=Walter |date=March 1, 1993 |volume=1 |chapter=Thermomechanical Stress Analysis of Novel Low Heat Rejection Cylinder Head Designs |article-number=930985 |doi=10.4271/930985 |chapter-url=http://papers.sae.org/930985/ |via=papers.sae.org}}</ref>

;Diehl 2013
<ref name="Diehl_2013_100">Peter Diehl: ''Auto Service Praxis'', magazine 06/2013, pp. 100</ref>

;Diesel
<ref name="Diesel_1892">[https://patents.google.com/patent/US542846 Method Of and Apparatus For Converting Heat Into Work], United States Patent No. 542,846, Filed Aug 26, 1892, Issued July 16, 1895, Inventor Rudolf Diesel of Berlin Germany</ref>
<ref name="Diesel_1893_EN">{{Cite book |last=Diesel |first=Rudolf |url=https://books.google.com/books?id=2fRLAAAAMAAJ&q=rudolph+diesel+experiments |title=Theory and Construction of a Rational Heat Motor |date=August 23, 1894 |publisher=E. & F. N. Spon}}</ref>
<ref name="Diesel_1893_1">[[Rudolf Diesel]]: ''[[Theorie und Konstruktion eines rationellen Wärmemotors zum Ersatz der Dampfmaschine und der heute bekannten Verbrennungsmotoren]]'', Springer, Berlin 1893, {{ISBN|978-3-642-64949-3}}.</ref>

<ref name="Diesel_1893_91">[[Rudolf Diesel]]: ''[[Theorie und Konstruktion eines rationellen Wärmemotors zum Ersatz der Dampfmaschine und der heute bekannten Verbrennungsmotoren]]'', Springer, Berlin 1893, {{ISBN|978-3-642-64949-3}}. p. 91</ref>
<ref name="Diesel_1893">{{Cite book |last=Diesel |first=Rudolf |url=https://archive.org/details/dieselsrational00diesgoog |title=Diesel's Rational Heat Motor: A Lecture |date=October 28, 1897 |publisher=Progressive Age Publishing Company |quote=diesel rational heat motor. |access-date=October 28, 2017}}</ref>
<ref name="Diesel_1895_2">[https://patents.google.com/patent/US608845 Internal-Combustion Engine], U.S. Patent number 608845, Filed Jul 15 1895, Issued August 9, 1898, Inventor Rudolf Diesel, Assigned to the Diesel Motor Company of America (New York)</ref>
<ref name="Diesel_1895_EN">{{Cite web |title=Patent Images |url=http://pdfpiw.uspto.gov/.piw?Docid=00608845&homeurl=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1%2526Sect2=HITOFF%2526d=PALL%2526p=1%2526u=%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r=1%2526f=G%2526l=50%2526s1=0608845.PN.%2526OS=PN/0608845%2526RS=PN/0608845&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page |website=Pdfpiw.uspto.gov}}</ref>

<ref name="Diesel_1913_1">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 1</ref>
<ref name="Diesel_1913_6">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 6</ref>
<ref name="Diesel_1913_8">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 8</ref>
<ref name="Diesel_1913_13">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 13</ref>
<ref name="Diesel_1913_17">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 17</ref>
<ref name="Diesel_1913_21">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 21</ref>
<ref name="Diesel_1913_22">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 22</ref>
<ref name="Diesel_1913_38">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 38</ref>
<ref name="Diesel_1913_64">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 64</ref>
<ref name="Diesel_1913_75">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 75</ref>
<ref name="Diesel_1913_78">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 78</ref>
<ref name="Diesel_1913_107">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 107</ref>
<ref name="Diesel_1913_110">[[Rudolf Diesel]]: ''Die Entstehung des Dieselmotors'', Springer, Berlin 1913, {{ISBN|978-3-642-64940-0}}. p. 110</ref>

;Dubbel 1981
<ref name="Dubbel_1981_712">Wolfgang Beitz, Karl-Heinz Küttner (ed): ''Dubbel – Taschenbuch für den Maschinenbau'', 14th edition, Springer, Berlin/Heidelberg 1981, {{ISBN|978-3-662-28196-3}}, p. 712</ref>

;Dubbel 2018
<ref name="Dubbel_2018_1191">Karl-Heinrich Grote, Beate Bender, Dietmar Göhlich (ed.): ''Dubbel – Taschenbuch für den Maschinenbau'', 25th edition, Springer, Heidelberg 2018, {{ISBN|978-3-662-54804-2}}, 1191 pp. (P79)</ref>
<ref name="Grote_2018_P93">Karl-Heinrich Grote, Beate Bender, Dietmar Göhlich (ed.): ''Dubbel – Taschenbuch für den Maschinenbau'', 25th edition, Springer, Heidelberg 2018, {{ISBN|978-3-662-54804-2}}, 1205 pp. (P93)</ref>

;Egger 2002
<ref name="Egger_2002">Klaus Egger, Johann Warga, Wendelin Klügl (auth.): ''[https://link.springer.com/article/10.1007%2FBF03226642#citeas Neues Common-Rail-Einspritzsystem mit Piezo-Aktorik für Pkw-Dieselmotoren]'', in MTZ – Motortechnische Zeitschrift, Springer, September 2002, Volume 63, Issue 9, pp. 696–704</ref>

;EPA 2004
<ref name="EPA_2004">{{Cite web |year=2004 |title=Medium and Heavy Duty Diesel Vehicle Modeling Using a Fuel Consumption Methodology |url=http://www.epa.gov/otaq/models/ngm/may04/crc0304c.pdf |archive-url=https://web.archive.org/web/20061010095104/http://www.epa.gov/otaq/models/ngm/may04/crc0304c.pdf |archive-date=2006-10-10 |url-status=dead |access-date=2017-04-25 |publisher=US EPA}}</ref>

;Hawks 1939

<ref name="Hawks_73">Ellison Hawks: ''How it works and how it's done'', Odhams Press, London 1939, p. 73</ref>

;Von Fersen

<ref name="vFersen_1986_272">Olaf von Fersen (ed.): ''Ein Jahrhundert Automobiltechnik: Personenwagen'', Springer, Düsseldorf 1986, {{ISBN|978-3-642-95773-4}}. p. 272</ref>
<ref name="vFersen_1986_274">Olaf von Fersen (ed.): ''Ein Jahrhundert Automobiltechnik: Personenwagen'', Springer, Düsseldorf 1986, {{ISBN|978-3-642-95773-4}}. p. 274</ref>
<ref name="vFersen_1987_156">Olaf von Fersen (ed.): ''Ein Jahrhundert Automobiltechnik: Nutzfahrzeuge'', Springer, Heidelberg 1987, {{ISBN|978-3-662-01120-1}}, p. 156</ref>

;Flatz 1946
<ref name="Flatz_1946">E. Flatz: ''Der neue luftgekühlte Deutz-Fahrzeug-Dieselmotor''. MTZ 8, 33–38 (1946)</ref>

;Fleet Owner 1964
<ref name="FleetOwner_1964_107">Fleet Owner, Volume 59, Primedia Business Magazines & Media, Incorporated, 1964, p. 107</ref>

;Hemmerlein 1991
<ref name="Hemmerlein_1991">{{Cite journal |last1=Hemmerlein |first1=Norbert |last2=Korte |first2=Volker |last3=Richter |first3=Herwig |last4=Schröder |first4=Günter |date=1991-02-01 |title=Performance, Exhaust Emissions and Durability of Modern Diesel Engines Running on Rapeseed Oil |journal=SAE Technical Paper Series |volume=1 |article-number=910848 |doi=10.4271/910848}}</ref>

;Kamo 1996
<ref name="Kamo_1995">{{Cite book |last1=Kamo |first1=Lloyd |title=SAE Technical Paper Series |last2=Kleyman |first2=Ardy |last3=Bryzik |first3=Walter |last4=Schwarz |first4=Ernest |date=February 1, 1995 |volume=1 |chapter=Recent Development of Tribological Coatings for High Temperature Engines |article-number=950979 |doi=10.4271/950979 |chapter-url=http://papers.sae.org/950979/ |via=papers.sae.org}}</ref>

;Karim 2015
<ref name="Karim_2015_2">Ghazi A. Karim: ''Dual-fuel Diesel engines'', CRC Press, Boca Raton London New York 2015, {{ISBN|978-1-4987-0309-3}}, p. 2</ref>

;Kremser 1942
<ref name="Kremser_1942_22">Hans Kremser (auth.): ''Der Aufbau schnellaufender Verbrennungskraftmaschinen für Kraftfahrzeuge und Triebwagen''. In: Hans List (ed.): Die Verbrennungskraftmaschine. Vol. 11. Springer, Wien 1942, {{ISBN|978-3-7091-5016-0}} p. 22</ref>
<ref name="Kremser_1942_23">Hans Kremser (auth.): ''Der Aufbau schnellaufender Verbrennungskraftmaschinen für Kraftfahrzeuge und Triebwagen''. In: Hans List (ed.): Die Verbrennungskraftmaschine. Vol. 11. Springer, Wien 1942, {{ISBN|978-3-7091-5016-0}} p. 23</ref>
<ref name="Kremser_1942_24">Hans Kremser (auth.): ''Der Aufbau schnellaufender Verbrennungskraftmaschinen für Kraftfahrzeuge und Triebwagen''. In: Hans List (ed.): Die Verbrennungskraftmaschine. Vol. 11. Springer, Wien 1942, {{ISBN|978-3-7091-5016-0}} p. 24</ref>
<ref name="Kremser_1942_125">Hans Kremser (auth.): ''Der Aufbau schnellaufender Verbrennungskraftmaschinen für Kraftfahrzeuge und Triebwagen''. In: Hans List (ed.): Die Verbrennungskraftmaschine. V. 11. Springer, Wien 1942, {{ISBN|978-3-7091-5016-0}} p. 125</ref>
<ref name="Kremser_1942_190">Hans Kremser (auth.): ''Der Aufbau schnellaufender Verbrennungskraftmaschinen für Kraftfahrzeuge und Triebwagen''. In: Hans List (ed.): Die Verbrennungskraftmaschine. Vol. 11. Springer, Wien 1942, {{ISBN|978-3-7091-5016-0}} p. 190</ref>

;List 1939
<ref name="List_1939_1">Hans List: ''Thermodynamik der Verbrennungskraftmaschine''. In: Hans List (ed.): ''Die Verbrennungskraftmaschine''. Vol. 2. Springer, Wien 1939, {{ISBN|978-3-7091-5197-6}}, p. 1</ref>

;MAN 1991
<ref name="MAN_1991_XI">Wilfried Lochte (auth): ''Vorwort'', in: Nutzfahrzeuge AG (ed.): ''Leistung und Weg: Zur Geschichte des MAN Nutzfahrzeugbaus'', Springer, Berlin/Heidelberg, 1991. {{ISBN|978-3-642-93490-2}}. p. XI</ref>
<ref name="MAN_436">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>
<ref name="MAN_438">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. 438.</ref>
<ref name="MAN_465">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. 465.</ref>

;Mau 1984
<ref name="Mau_1984_7">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 7</ref>
<ref name="Mau_1984_8">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 8</ref>
<ref name="Mau_1984_9_11">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. pp. 9–11</ref>
<ref name="Mau_1984_15">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 15</ref>
<ref name="Mau_1984_16">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 16</ref>
<ref name="Mau_1984_17">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 17</ref>
<ref name="Mau_1984_23">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 23</ref>
<ref name="Mau_1984_33">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 33</ref>
<ref name="Mau_1984_42">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 42</ref>
<ref name="Mau_1984_43">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 43</ref>
<ref name="Mau_1984_50">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 50</ref>
<ref name="Mau_1984_pp53">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. pp. 53</ref>
<ref name="Mau_1984_121">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 121</ref>
<ref name="Mau_1984_129">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 129</ref>
<ref name="Mau_1984_136">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 136</ref>
<ref name="Mau_1984_148">Günter Mau: ''Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb'', Vieweg (Springer), Braunschweig/Wiesbaden 1984, {{ISBN|978-3-528-14889-8}}. p. 148</ref>

;Merker 2014
<ref name="Merker_2014_48">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 48</ref>
<ref name="Merker_2014_58">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 58</ref>
<ref name="Merker_2014_179">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 179</ref>
<ref name="Merker_2014_264">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 264</ref>
<ref name="Merker_2014_273">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 273</ref>
<ref name="Merker_2014_276">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 276</ref>
<ref name="Merker_2014_280">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 280</ref>
<ref name="Merker_2014_284">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 284</ref>
<ref name="Merker_2014_381">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 381</ref>
<ref name="Merker_2014_382">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 382</ref>

;Moon 1974
<ref name="Moon_1974">{{Cite book |last=Moon |first=John F. |url=https://archive.org/details/rudolfdieseldies00moon |title=Rudolf Diesel and the Diesel Engine |publisher=Priory Press |year=1974 |isbn=978-0-85078-130-4 |location=London |ref=Moon, 1974 |url-access=registration}}</ref>

;Nanlin 1993
<ref name="Nanlin_1993">{{Cite book |last1=Nanlin |first1=Zhang |title=SAE Technical Paper Series |last2=Shengyuan |first2=Zhong |last3=Jingtu |first3=Feng |last4=Jinwen |first4=Cai |last5=Qinan |first5=Pu |last6=Yuan |first6=Fan |date=March 1, 1993 |volume=1 |chapter=Development of Model 6105 Adiabatic Engine |article-number=930984 |doi=10.4271/930984 |chapter-url=http://papers.sae.org/930984/ |via=papers.sae.org}}</ref>

;Von Philippovich 1939
<ref name="vPhilippovich_1939_41">A. v. Philippovich (auth.): ''Die Betriebsstoffe für Verbrennungskraftmaschinen''. In: Hans List (ed.): ''Die Verbrennungskraftmaschine''. Vol. 1. Springer, Wien 1939, {{ISBN|978-3-662-27981-6}}. p. 41</ref>
<ref name="vPhilippovich_1939_42">A. v. Philippovich (auth.): ''Die Betriebsstoffe für Verbrennungskraftmaschinen''. In: Hans List (ed.): ''Die Verbrennungskraftmaschine''. Vol. 1. Springer, Wien 1939, {{ISBN|978-3-662-27981-6}}. p. 42</ref>
<ref name="vPhilippovich_1939_43">A. v. Philippovich (auth.): ''Die Betriebsstoffe für Verbrennungskraftmaschinen''. In: Hans List (ed.): ''Die Verbrennungskraftmaschine''. Vol. 1. Springer, Wien 1939, {{ISBN|978-3-662-27981-6}}. p. 43</ref>
<ref name="vPhilippovich_1939_45">A. v. Philippovich (auth.): ''Die Betriebsstoffe für Verbrennungskraftmaschinen''. In: Hans List (ed.): ''Die Verbrennungskraftmaschine''. Vol. 1. Springer, Wien 1939, {{ISBN|978-3-662-27981-6}}. p. 45</ref>

;Pischinger 2016
<ref name="Pischinger_2016_348">Stefan Pischinger, Ulrich Seiffert (ed.): ''Vieweg Handbuch Kraftfahrzeugtechnik''. 8th edition, Springer, Wiesbaden 2016. {{ISBN|978-3-658-09528-4}}. p. 348.</ref>

;Reif
<ref name="Reif_2012_103">Konrad Reif (ed.): ''Dieselmotor-Management – Systeme Komponenten und Regelung'', 5th edition, Springer, Wiesbaden 2012, {{ISBN|978-3-8348-1715-0}}, p. 103</ref>
<ref name="Reif_2012_223">Konrad Reif (ed.): ''Dieselmotor-Management – Systeme Komponenten und Regelung'', 5th edition, Springer, Wiesbaden 2012, {{ISBN|978-3-8348-1715-0}}, p. 223</ref>
<ref name="Reif_2012_271">Konrad Reif (ed.): ''Dieselmotor-Management – Systeme Komponenten und Regelung'', 5th edition, Springer, Wiesbaden 2012, {{ISBN|978-3-8348-1715-0}}, p. 271</ref>
<ref name="Reif_2012_286">Konrad Reif (ed.): ''Dieselmotor-Management – Systeme Komponenten und Regelung'', 5th edition, Springer, Wiesbaden 2012, {{ISBN|978-3-8348-1715-0}}, p. 286</ref>

<ref name="Reif_2014_10">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 10</ref>
<ref name="Reif_2014_11">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 11</ref>
<ref name="Reif_2014_12">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 12</ref>
<ref name="Reif_2014_13">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 13</ref>
<ref name="Reif_2014_18">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 18</ref>
<ref name="Reif_2014_23">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 23</ref>
<ref name="Reif_2014_28">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 28</ref>
<ref name="Reif_2014_31">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 31</ref>
<ref name="Reif_2014_41">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 41</ref>
<ref name="Reif_2014_53">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 53</ref>
<ref name="Reif_2014_70">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 70</ref>
<ref name="Reif_2014_136">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 136</ref>
<ref name="Reif_2014_140">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 140</ref>
<ref name="Reif_2014_182">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 182</ref>

<ref name="Reif_O_2014_7">Konrad Reif (ed.): ''Ottomotor-Management: Steuerung, Regelung und Überwachung'', Springer, Wiesbaden 2014, {{ISBN|978-3-8348-1416-6}}, p. 7</ref>

<ref name="Reif_2017_16">Konrad Reif (ed.): ''Grundlagen Fahrzeug- und Motorentechnik''. Springer Fachmedien, Wiesbaden 2017, {{ISBN|978-3-658-12635-3}}. pp. 16</ref>

;Schreiner 2014
<ref name="Schreiner_2014_22">Klaus Schreiner: ''Basiswissen Verbrennungsmotor: Fragen – rechnen – verstehen – bestehen''. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06187-6}}, p. 22.</ref>

;Stan 2017
<ref name="Stan_2017_252">Cornel Stan: ''Thermodynamik des Kraftfahrzeugs: Grundlagen und Anwendungen – mit Prozesssimulationen'', Springer, Berlin/Heidelberg 2017, {{ISBN|978-3-662-53722-0}}. p. 252</ref>

;SAE 2017
<ref name="Papers on adiabatic engines">{{Cite web |title=Browse Papers on Adiabatic engines : Topic Results |url=http://topics.sae.org/adiabatic-engines/papers/ |url-status=dead |archive-url=https://web.archive.org/web/20170823204928/http://topics.sae.org/adiabatic-engines/papers/ |archive-date=August 23, 2017 |access-date=April 30, 2018 |website=topics.sae.org |publisher=SAE International |df=mdy-all}}</ref>

;Sass 1962
<ref name="Sass_1962_395">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 395</ref>
<ref name="Sass_1962_398">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 398</ref>
<ref name="Sass_1962_399">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 399</ref>
<ref name="Sass_1962_400">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 400</ref>
<ref name="Sass_1962_402">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 402</ref>
<ref name="Sass_1962_408">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 408</ref>
<ref name="Sass_1962_412">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 412</ref>
<ref name="Sass_1962_414">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 414</ref>
<ref name="Sass_1962_415">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 415</ref>
<ref name="Sass_1962_444">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 444</ref>
<ref name="Sass_1962_462">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 462</ref>
<ref name="Sass_1962_463">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 463</ref>
<ref name="Sass_1962_464">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 464</ref>
<ref name="Sass_1962_466">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 466</ref>
<ref name="Sass_1962_467">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 467</ref>
<ref name="Sass_1962_474">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 474</ref>
<ref name="Sass_1962_475">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 475</ref>
<ref name="Sass_1962_479">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 479</ref>
<ref name="Sass_1962_480">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 480</ref>
<ref name="Sass_1962_484">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 484</ref>
<ref name="Sass_1962_485">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 485</ref>
<ref name="Sass_1962_486">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 486</ref>
<ref name="Sass_1962_487">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 487</ref>
<ref name="Sass_1962_493">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 493</ref>
<ref name="Sass_1962_501">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 501</ref>
<ref name="Sass_1962_502">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 502</ref>
<ref name="Sass_1962_505">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 505</ref>
<ref name="Sass_1962_506">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 506</ref>
<ref name="Sass_1962_518">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 518</ref>
<ref name="Sass_1962_523">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 523</ref>
<ref name="Sass_1962_524">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 524</ref>
<ref name="Sass_1962_530">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 530</ref>
<ref name="Sass_1962_532">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 532</ref>
<ref name="Sass_1962_541">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 541</ref>
<ref name="Sass_1962_545">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 545</ref>
<ref name="Sass_1962_559">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 559</ref>
<ref name="Sass_1962_569">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 569</ref>
<ref name="Sass_1962_610">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 610</ref>
<ref name="Sass_1962_644">Friedrich Sass: ''Geschichte des deutschen Verbrennungsmotorenbaus von 1860 bis 1918'', Springer, Berlin/Heidelberg 1962, {{ISBN|978-3-662-11843-6}}. p. 644</ref>

;Schwarz 1993
<ref name="Schwarz_1993">{{Cite book |last1=Schwarz |first1=Ernest |title=SAE Technical Paper Series |last2=Reid |first2=Michael |last3=Bryzik |first3=Walter |last4=Danielson |first4=Eugene |date=March 1, 1993 |volume=1 |chapter=Combustion and Performance Characteristics of a Low Heat Rejection Engine |article-number=930988 |doi=10.4271/930988 |chapter-url=http://papers.sae.org/930988/ |via=papers.sae.org}}</ref>

;Schwarz 2012
<ref name="Schwarz_2012_102">Christian Schwarz, Rüdiger Teichmann: ''Grundlagen Verbrennungsmotoren: Funktionsweise, Simulation, Messtechnik''. Springer. Wiesbaden 2012, {{ISBN|978-3-8348-1987-1}}, p. 102</ref>

;Sittauer 1990
<ref name="Sittauer_1990_70">Sittauer, Hans L. (1990), ''Nicolaus August Otto Rudolf Diesel, Biographien hervorragender Naturwissenschaftler, Techniker und Mediziner'' (in German), 32 (4th ed.), Leipzig, DDR: Springer (BSB Teubner), {{ISBN|978-3-322-00762-9}}. p. 70</ref>
<ref name="Sittauer_1990_71">Sittauer, Hans L. (1990), ''Nicolaus August Otto Rudolf Diesel, Biographien hervorragender Naturwissenschaftler, Techniker und Mediziner'' (in German), 32 (4th ed.), Leipzig, DDR: Springer (BSB Teubner), {{ISBN|978-3-322-00762-9}}. p. 71</ref>
<ref name="Sittauer_1990_74">Sittauer, Hans L. (1990), ''Nicolaus August Otto Rudolf Diesel, Biographien hervorragender Naturwissenschaftler, Techniker und Mediziner'' (in German), 32 (4th ed.), Leipzig, DDR: Springer (BSB Teubner), {{ISBN|978-3-322-00762-9}}. p. 74</ref>

;Soimar2000
<ref name="Soimar_2000">{{Cite journal |last=Michael Soimar |date=April 2000 |title=The Challenge Of CVTs In Current Heavy-Duty Powertrains |url=http://findarticles.com/p/articles/mi_m0FZX/is_4_66/ai_62371160/print?tag=artBody;col1 |url-status=dead |journal=Diesel Progress North American Edition |archive-url=https://web.archive.org/web/20081207140743/http://findarticles.com/p/articles/mi_m0FZX/is_4_66/ai_62371160/print?tag=artBody%3Bcol1 |archive-date=December 7, 2008 |df=mdy-all}}</ref>

;Speck 2005
<ref name="Speck_2005">Peter Speck: ''Employability – Herausforderungen für die strategische Personalentwicklung: Konzepte für eine flexible, innovationsorientierte Arbeitswelt von morgen'', 2nd edition, Springer, 2005, {{ISBN|978-3409226837}}, p. 21</ref>

;Tschöke 2018
<ref name="Tschöke_2018_6">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 6</ref>
<ref name="Tschöke_2018_7">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 7</ref>
<ref name="Tschöke_2018_9">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 9</ref>
<ref name="Tschöke_2018_10">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 10</ref>
<ref name="Tschöke_2018_295">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 295</ref>
<ref name="Tschöke_2018_310">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 310</ref>
<ref name="Tschöke_2018_666">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 666</ref>
<ref name="Tschöke_2018_981">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 981</ref>
<ref name="Tschöke_2018_1000">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'' 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 1000</ref>
<ref name="Tschöke_2018_1066">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 1066</ref>
<ref name="Tschöke_2018_1110">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 1110</ref>

;Tucker-Jones 2015
<ref name="Tucker-Jones_2015_36">Anthony Tucker-Jones: ''T-34: The Red Army's Legendary Medium Tank'', Pen and Sword, 2015, {{ISBN|978-1473854703}}, p. 36 and 37</ref>

;Vogler 2016
<ref name="Vogler_2016_34">Carl-Heinz Vogler: ''Unimog 406 – Typengeschichte und Technik''. Geramond, München 2016, {{ISBN|978-3-86245-576-8}}. p. 34.</ref>

;Waibel 2016
<ref name="Waibel_2016_159">Barbara Waibel: ''Die Hindenburg: Gigant der Lüfte'', Sutton, 2016, {{ISBN|978-3954007226}}. p. 159</ref>

;Zhao 2009
<ref name="Zhao_2009_8">Hua Zhao: ''[https://books.google.com/books?id=jcikAgAAQBAJ Advanced Direct Injection Combustion Engine Technologies and Development: Diesel Engines]'', Elsevier, 2009, {{ISBN|978-1845697457}}, p. 8</ref>
<ref name="Zhao_2009_45">Hua Zhao: ''[https://books.google.com/books?id=jcikAgAAQBAJ Advanced Direct Injection Combustion Engine Technologies and Development: Diesel Engines]'', Elsevier, 2009, {{ISBN|978-1845697457}}, p. 45 and 46</ref>

;Misc.

<ref name="Ultra low sulfur diesel">{{Cite web |title=MSDS Low Sulfur Diesel #2.doc |url=http://www.petrocard.com/Products/MSDS-ULS.pdf |url-status=live |archive-url=https://web.archive.org/web/20110715071132/http://www.petrocard.com/Products/MSDS-ULS.pdf |archive-date=July 15, 2011 |access-date=December 21, 2010 |df=mdy}}</ref>
<ref name="FreeLib_1995">The Free Library [http://www.thefreelibrary.com/DETROIT+DIESEL+INTRODUCES+DDEC+ETHER+START-a016648399] {{Webarchive|url=https://web.archive.org/web/20170913044127/https://www.thefreelibrary.com/DETROIT+DIESEL+INTRODUCES+DDEC+ETHER+START-a016648399 |date=September 13, 2017 }} "Detroit Diesel Introduces DDEC Ether Start", March 13, 1995, accessed March 14, 2011.</ref>
<ref name="EngTips">{{Cite web |title=Engine & fuel engineering – Diesel Noise | date=November 9, 2005 |url=http://www.eng-tips.com/viewthread.cfm?qid=139341&page=7 |access-date=November 1, 2008}}</ref>
<ref name="Bennett2016">{{Cite book |last=Sean Bennett |url=https://books.google.com/books?id=dn9TCwAAQBAJ&pg=PA97 |title=Medium/Heavy Duty Truck Engines, Fuel & Computerized Management Systems |date=2016 |publisher=Cengage Learning |isbn=978-1-305-57855-5 |pages=97–}}</ref>
<ref name="DictionaryCH">{{Cite book |url=https://archive.org/details/internationaldir0013unse |title=International Directory of Company Histories |publisher=St. James Press |year=1996 |isbn=978-1-55862-327-9 |url-access=registration}}</ref>
<ref name="Agritechnica_2017">{{Cite web |date=November 2, 2017 |title=History of the DLG – Agritechnica's organizer |url=https://www.agritechnica.com/en/press/#!/news/history-of-the-dlg-agritechnicas-organizer_59fad080 |access-date=February 19, 2019}}</ref>
<ref name="Oldmachinepress_2012">{{Cite web |last=Pearce |first=William |date=September 1, 2012 |title=Fairbanks Morse Model 32 Stationary Engine |url=https://oldmachinepress.com/2012/08/31/fairbanks-morse-model-32-stationary-engine/}}</ref>
<ref name="TheEngineer_2003">{{Cite web |date=6 November 2003 |title=Perfect piezo |url=https://www.theengineer.co.uk/issues/24-october-2003/perfect-piezo/ |access-date=4 May 2016 |publisher=The Engineer |quote=At the recent Frankfurt motor show, Siemens, Bosch and Delphi all launched piezoelectric fuel injection systems. |archive-date=February 24, 2019 |archive-url=https://web.archive.org/web/20190224173527/https://www.theengineer.co.uk/issues/24-october-2003/perfect-piezo/ |url-status=dead }}</ref>
<ref name="NPR_2015">{{Cite news |date=8 October 2015 |title='It Was Installed For This Purpose,' VW's U.S. CEO Tells Congress About Defeat Device |publisher=NPR |url=https://www.npr.org/sections/thetwo-way/2015/10/08/446861855/volkswagen-u-s-ceo-faces-questions-on-capitol-hill |access-date=19 October 2015}}</ref>
<ref name="EPA_2015">{{Cite web |date=18 September 2015 |title=EPA, California Notify Volkswagen of Clean Air Act Violations / Carmaker allegedly used software that circumvents emissions testing for certain air pollutants |url=https://yosemite.epa.gov/opa/admpress.nsf/a883dc3da7094f97852572a00065d7d8/dfc8e33b5ab162b985257ec40057813b |archive-url=https://web.archive.org/web/20170302172909/https://yosemite.epa.gov/opa/admpress.nsf/a883dc3da7094f97852572a00065d7d8/dfc8e33b5ab162b985257ec40057813b |url-status=dead |archive-date=March 2, 2017 |access-date=1 July 2016 |publisher=EPA |location=US}}</ref>
<ref name="Jordans_2015">{{Cite news |last=Jordans |first=Frank |date=21 September 2015 |title=EPA: Volkswagon {{sic|nolink=y}} Thwarted Pollution Regulations For 7 Years |publisher=CBS Detroit |agency=Associated Press |url=http://detroit.cbslocal.com/2015/09/21/epa-volkswagon-thwarted-pollution-regulations-for-7-years/ |access-date=24 September 2015}}</ref>
<ref name="Spiegel_2015">{{Cite news |date=28 September 2015 |title=Abgasaffäre: VW-Chef Müller spricht von historischer Krise |work=Der Spiegel |agency=Reuters |url=http://www.spiegel.de/wirtschaft/unternehmen/volkswagen-chef-mueller-sieht-konzern-in-historischer-krise-a-1055148.html |access-date=28 September 2015}}</ref>
<ref name="NRAO">{{Cite web |title=NRAO Green Bank Site RFI Regulations for Visitors |url=http://www.gb.nrao.edu/visitors/TheEnemyIsUs.pdf |archive-url=https://web.archive.org/web/20060504015945/http://www.gb.nrao.edu/visitors/TheEnemyIsUs.pdf |archive-date=2006-05-04 |url-status=live |access-date=October 14, 2016 |publisher=National Radio Astronomy Observatory |page=2}}</ref>
<ref name="Rochester">{{Cite web |title=Archived copy |url=http://www.cs.rochester.edu/u/jag/vw/engine/fi/injpump.html |url-status=dead |archive-url=https://web.archive.org/web/20090107170106/http://www.cs.rochester.edu/u/jag/vw/engine/fi/injpump.html |archive-date=January 7, 2009 |access-date=2009-01-11 |df=mdy-all}}</ref>
<ref name="buckman">{{Cite web |title=Archived copy |url=http://www.oldengine.org/members/diesel/Ambac/AmbacMenu1.htm |url-status=dead |archive-url=https://web.archive.org/web/20100123015243/http://www.oldengine.org/members/diesel/Ambac/AmbacMenu1.htm |archive-date=January 23, 2010 |access-date=2009-01-08 |df=mdy-all}}</ref>
<ref name="Dieselpower_2007">{{Cite journal |date=June 2007 |title=Diesel Fuel Injection – How-It-Works |url=http://www.dieselpowermag.com/tech/general/0706dp_diesel_fuel_injection/viewall.html |journal=Diesel Power |access-date=November 24, 2012}}</ref>
<ref name="Firstdiesel_2009">{{Cite web |title=Diesel injection pumps, Diesel injectors, Diesel fuel pumps, turbochargers, Diesel trucks all at First Diesel Injection LTD |url=http://www.firstdiesel.com |url-status=live |archive-url=https://web.archive.org/web/20110203070641/http://firstdiesel.com/ |archive-date=February 3, 2011 |access-date=May 11, 2009 |publisher=Firstdiesel.com |df=mdy}}</ref>
<ref name="Dieselhub">[http://www.dieselhub.com/tech/idi-vs-di.html "IDI vs DI"] Diesel hub</ref>
<ref name="Diesel_1895">US patent (granted in 1895) [http://pdfpiw.uspto.gov/.piw?docid=00542846&SectionNum=2&IDKey=1BB1E16A8D0F&HomeUrl=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1%2526Sect2=HITOFF%2526d=PALL%2526p=1%2526u=%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r=1%2526f=G%2526l=50%2526s1=0542846.PN.%2526OS=PN/0542846%2526RS=PN/0542846 #542846 pdfpiw.uspto.gov] {{Webarchive|url=https://web.archive.org/web/20210426124258/http://pdfpiw.uspto.gov/.piw?docid=00542846&SectionNum=2&IDKey=1BB1E16A8D0F&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D0542846.PN.%2526OS%3DPN%2F0542846%2526RS%3DPN%2F0542846 |date=April 26, 2021 }}</ref>
<ref name="Diesel_1898">{{Cite web |title=Patent Images |url=http://pdfpiw.uspto.gov/.piw?Docid=00608845&homeurl=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1%2526Sect2=HITOFF%2526d=PALL%2526p=1%2526u=%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r=1%2526f=G%2526l=50%2526s1=0608845.PN.%2526OS=PN/0608845%2526RS=PN/0608845&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page |access-date=October 28, 2017 |website=Pdfpiw.uspto.gov}}</ref>
<ref name="e-rara.ch">{{Cite book |last1=Diesel |first1=Rudolf |title=Die Entstehung des Dieselmotors |date=1913 |publisher=Verlag von Julius Springer |doi=10.3931/e-rara-11467 |url=https://www.e-rara.ch/zut/doi/10.3931/e-rara-11467 |access-date=2025-07-12 |df=mdy-all}}</ref>
<ref name="RiversHarbors">{{Cite book |url=https://books.google.com/books?id=Xko1AQAAMAAJ&pg=PA590 |title=Rivers and Harbors |year=1921 |pages=590–}}</ref>
<ref name="Solomon">{{Cite book |last=Brian Solomon |url=https://books.google.com/books?id=bVEhihy7tKEC&pg=PA34 |title=American Diesel Locomotives | year=2000 |publisher=Voyageur Press |isbn=978-1-61060-605-9 |pages=34–}}</ref>
<ref name="Hartman">{{Cite book |last=Jeff Hartman |url=https://books.google.com/books?id=SvG0gq4DxecC&pg=PA2 |title=Turbocharging Performance Handbook | date=September 9, 2023 |publisher=MotorBooks International |isbn=978-1-61059-231-4 |pages=2–}}</ref>
<ref name="Busch">{{Cite book |url=https://books.google.com/books?id=FEV-AAAAIAAJ&q=diesel+engine |title=The Diesel engine |publisher=Busch–Sulzer Bros. Diesel Engine Company, St. Louis Busch |year=1913}}</ref>
<ref name="Tucker2014">{{Cite book |last=Spencer C. Tucker |url=https://books.google.com/books?id=DBwTBQAAQBAJ&pg=PA1506 |title=World War I: The Definitive Encyclopedia and Document Collection &#91;5 volumes&#93;: The Definitive Encyclopedia and Document Collection |date=2014 |publisher=ABC-CLIO |isbn=978-1-85109-965-8 |pages=1506–}}</ref>
<ref name="Klooster2009">{{Cite book |last=John W. Klooster |url=https://books.google.com/books?id=WKuG-VIwID8C&pg=PA245 |title=Icons of Invention: The Makers of the Modern World from Gutenberg to Gates |publisher=ABC-CLIO |year=2009 |isbn=978-0-313-34743-6 |pages=245–}}</ref>
<ref name="Pease2003">{{Cite book |last=John Pease |url=https://books.google.com/books?id=y2QfAQAAIAAJ |title=The History of J & H McLaren of Leeds: Steam & Diesel Engine Makers |publisher=Landmark Pub. |year=2003 |isbn=978-1-84306-105-2}}</ref>
<ref name="AutomobileQuarterly">{{Cite book |url=https://books.google.com/books?id=ez9WAAAAMAAJ |title=Automobile Quarterly |publisher=Automobile Quarterly |year=1974}}</ref>
<ref name="EuDaly_2016_160">Kevin EuDaly, Mike Schafer, Steve Jessup, Jim Boyd, Andrew McBride, Steve Glischinski: '' The Complete Book of North American Railroading'', Book Sales, 2016, {{ISBN|978-0785833895}}, p. 160</ref>
<ref name="Long_2013">Brian Long: Zero Carbon Car: Green Technology and the Automotive Industry, Crowood, 2013, {{ISBN|978-1847975140}}.</ref>
<ref name="Comb in IC">{{Cite journal |title=Combustion in IC (Internal Combustion) Engines |url=http://me.queensu.ca/courses/MECH435/6.+Combustion+in+IC+Engines.ppt |url-status=dead |pages=Slide 37 |archive-url=https://web.archive.org/web/20050816030858/http://me.queensu.ca/courses/MECH435/6.%20Combustion%20in%20IC%20Engines.ppt |archive-date=August 16, 2005 |access-date=November 1, 2008 |df=mdy-all}}</ref>
<!-- Unused (but not unloved)
<ref name="Bosch_1993_27">Robert Bosch (ed.): ''Diesel-Einspritztechnik'', Springer, Berlin/Heidelberg 1993, {{ISBN|978-3662009048}}, p. 27</ref>
<ref name="Böge_2017_1190">Alfred Böge, Wolfgang Böge (ed.): ''Handbuch Maschinenbau – Grundlagen und Anwendungen der Maschinenbau-Technik'', 23rd edition, Springer, Wiesbaden 2017, {{ISBN|978-3-658-12528-8}}, p. 1190</ref>
<ref name="Dubbel_2018_1187">Karl-Heinrich Grote, Beate Bender, Dietmar Göhlich (ed.): ''Dubbel – Taschenbuch für den Maschinenbau'', 25th edition, Springer, Heidelberg 2018, {{ISBN|978-3-662-54804-2}}, 1187 pp. (P75)</ref>
<ref name="List_1939_28">Hans List: ''Thermodynamik der Verbrennungskraftmaschine''. In: Hans List (ed.): ''Die Verbrennungskraftmaschine''. Vol. 2. Springer, Wien 1939, {{ISBN|978-3-7091-5197-6}}, pp. 28, 29</ref>
<ref name="Merker_2014_439">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 439</ref>
<ref name="Merker_2014_472">Günter P. Merker, Rüdiger Teichmann (ed.): ''Grundlagen Verbrennungsmotoren – Funktionsweise · Simulation · Messtechnik'', 7th edition, Springer, Wiesbaden 2014, {{ISBN|978-3-658-03194-7}}, p. 472</ref>
<ref name="Pischinger_2016_377–379">Stefan Pischinger, Ulrich Seiffert (ed.): ''Vieweg Handbuch Kraftfahrzeugtechnik''. 8th edition, Springer, Wiesbaden 2016. {{ISBN|978-3-658-09528-4}}. p. 377–379.</ref>
<ref name="Reif_2014_17">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 17</ref>
<ref name="Reif_2014_40">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 40</ref>
<ref name="Reif_2014_171">Konrad Reif (ed.): ''Dieselmotor-Management im Überblick''. 2nd edition. Springer, Wiesbaden 2014, {{ISBN|978-3-658-06554-6}}. p. 171</ref>
<ref name="Reif_2020_31">Konrad Reif (ed.): ''Dieselmotor-Management: Systeme, Komponenten, Steuerung und Regelung''. 6th edition. Springer, Wiesbaden 2020, {{ISBN|978-3-658-25071-3}}. p. 31</ref>
<ref name="Tschöke_2018_702">Helmut Tschöke, Klaus Mollenhauer, Rudolf Maier (ed.): ''Handbuch Dieselmotoren'', 8th edition, Springer, Wiesbaden 2018, {{ISBN|978-3-658-07696-2}}, p. 702</ref>
<ref name="Brit2and4">[https://www.britannica.com/EBchecked/topic/162716/diesel-engine/45706/Two-stroke-and-four-stroke-engines "Two and Four Stroke Diesel Engines"]. Encyclopædia Britannica</ref>
-->
}}

==External links==
{{Commons category|Diesel engines}}
{{Commons|Rudolf Diesel}}
{{Collier's poster|Diesel Engine}}
* {{Cite web |title=Diesel Information Hub |url=https://dieselinformation.aecc.eu/ |publisher=Association for Emissions Control by Catalyst |access-date=July 25, 2018 |archive-date=February 24, 2020 |archive-url=https://web.archive.org/web/20200224174227/https://dieselinformation.aecc.eu/ |url-status=dead }}
* {{Internet Archive short film | 0613_Diesel_Story_The_06_30_42_18 | The Diesel Story (1952)}}
* {{YouTube| DDLJgUaBpmM | "Introduction to Two Stroke Marine Diesel Engine" }}
* {{YouTube| wCA5pInfPpM | "The Engine That Powers the World" BBC Documentary }}

===Patents===
* [http://pdfpiw.uspto.gov/.piw?docid=00542846&SectionNum=2&IDKey=1BB1E16A8D0F&HomeUrl=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1%2526Sect2=HITOFF%2526d=PALL%2526p=1%2526u=%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r=1%2526f=G%2526l=50%2526s1=0542846.PN.%2526OS=PN/0542846%2526RS=PN/0542846 Method of and Apparatus for Converting Heat into Work. # 542846 filed 1892] {{Webarchive|url=https://web.archive.org/web/20210426124258/http://pdfpiw.uspto.gov/.piw?docid=00542846&SectionNum=2&IDKey=1BB1E16A8D0F&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D0542846.PN.%2526OS%3DPN%2F0542846%2526RS%3DPN%2F0542846 |date=April 26, 2021 }}
* [http://pdfpiw.uspto.gov/.piw?Docid=00608845&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D0608845.PN.%2526OS%3DPN%2F0608845%2526RS%3DPN%2F0608845&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page Internal Combustion Engine #608845 filed 1895]

{{Heat engines}}
{{Automotive engine}}
{{Automobile configuration}}

{{Authority control}}

[[Category:Diesel engines| ]]
[[Category:Internal combustion piston engines]]
[[Category:1893 introductions]]
[[Category:1893 in Germany]]
[[Category:German inventions]]