Editing Opposed-piston engine (section)

== History ==

=== 1880s to 1930s ===
[[File:Atkinson Opposed Piston Engine.gif|thumb|upright=0.8|Animation of the Atkinson differential engine]]
[[File:Jumo205 cutview 02.jpg|thumb|1932 [[Junkers Jumo 205]] diesel aircraft engine]]

One of the first opposed-piston engines was the 1882 [[Atkinson cycle#Atkinson "Differential Engine"|Atkinson differential engine]],<ref>{{cite book | last = Gingery | first = Vincent | title = Building the Atkinson Differential Engine | publisher = David J. Gingery Publishing | isbn = 1878087231 | year = 2000 }}</ref> which has a power stroke on every rotation of the crankshaft (compared with every second rotation for the contemporary [[Otto cycle]] engine), but it was not a commercial success.<ref>{{cite web |title=Atkinson Differential Engine Replica - Gas Engines |url=https://www.gasenginemagazine.com/gas-engines/atkinson-differential-engine-replica-zm0z18amzhur |website=GasEngineMagazine.com |date=13 March 2018 |access-date=22 November 2019 }}</ref>

In 1898, an Oechelhäuser two-stroke opposed-piston engine producing {{convert|600|hp|kW|0|abbr=on}} was installed at the Hoerde ironworks.<ref>{{cite journal |title=Large Gas Engines on the Continent |journal=Page's Weekly |date=23 June 1905 |pages=1336–1337 }}</ref> This design of engine was also produced under licence by manufacturers including Deutsche Kraftgas Gesellschaft in Germany and [[William Beardmore & Company|William Beardmore & Sons]] in the United Kingdom.<ref>{{cite conference |last1=Stokes |first1=Jason W. B. |last2=Cunningham |first2=Jason |title=The Oechelhauser Gas Engine in Great Britain: Paper Read Before the Glasgow University Engineering Society |date=11 November 1909 |url=https://books.google.com/books?id=mZB8MQAACAAJ |publisher=[[William Beardmore & Company]] }}</ref>

In 1901, the Kansas City Lightning Balanced Gas and Gasoline Engines were gasoline engines producing {{convert|4|-|25|hp|kW|0|abbr=on}}.<ref>{{cite web |title=Struck by Lightning: The Kansas City Hay Press Co. - Gas Engines |url=https://www.farmcollector.com/gas-engines/kansas-city-hay-press-co-engines |website=FarmCollector.com |date=April 1999 |access-date=26 November 2019 }}</ref>

An early opposed-piston car engine was produced by the French company [[Gobron-Brillié]] around 1900. On 31 March 1904,<ref>{{cite book |editor-last=Berghaus |editor-first=Günter |date=2009 |title=Futurism And The Technological Imagination |publisher=Rudopi |location=Amsterdam & New York |page=8 |isbn=978-90-420-2747-3 |url=https://books.google.com/books?id=MOIzDwAAQBAJ&pg=PA8 |via=Google Books |access-date=9 October 2024}}</ref><ref>{{cite web |url=http://www.racingcampbells.com/content/world.land.speed.record.asp |title=World Land Speed Records |publisher=RacingCampbells.com |archive-url=https://web.archive.org/web/20070831073900/http://www.racingcampbells.com/content/world.land.speed.record.asp |archive-date=31 August 2007 |access-date=8 October 2024}}</ref> a Gobron-Brillié car powered by the opposed-piston engine was the first car ever to exceed 150&nbsp;km/h with a "World's Record Speed" of {{convert|152.54|km/h|mph|0|abbr=on}}.<ref>{{cite journal |title=Nice Automobile Week: Third, Coupe Henri de Rothschild |journal=The Automotor Journal |date=9 April 1904 |page=426 }}</ref> On 17 July 1904, the Gobron-Brillié car became the first to exceed {{convert|100|mph|km/h|0|abbr=on}} for the flying kilometre.<ref name=uniquecarsandparts1>{{cite web |url=http://www.uniquecarsandparts.com.au/lost_marques_gobron_brillie.htm |title=Gobron-Brillie history |website=UniqueCarsAndParts.com.au |archive-url=https://web.archive.org/web/20130825070116/http://www.uniquecarsandparts.com.au/lost_marques_gobron_brillie.htm |archive-date=25 August 2013}}</ref> The engine used a single crankshaft at one end of the cylinders and a crosshead for the opposing piston.

Another early opposed piston car engine was in the Scottish [[Arrol-Johnston]] car, which appears to have been first installed in their 10&nbsp;hp buckboard c1900. The engine was described and illustrated in some detail in the account of their 12-15&nbsp;hp car exhibited at the 1905 Olympia Motor-Show.<ref>{{cite journal |title=The New Arrol-Johnston Petrol Car – Part II |journal=The Automotor Journal |date=25 November 1905 |pages=1467–1469 }}</ref><ref>{{cite journal |title=The New Arrol-Johnston Petrol Car – Part III |journal=The Automotor Journal |date=2 December 1905 |pages=1495–1496 }}</ref> The engine was a four-stroke with two cylinders (with opposed pistons in each) with the crankshaft underneath and the pistons connected by lever arms to the two-throw crankshaft.

The first diesel engine with opposed pistons was a prototype built at [[Kolomna Locomotive Works]] in Russia. The designer, Raymond A. Koreyvo, patented the engine in France on 6 November 1907 and displayed the engine at international exhibitions, but it did not reach production. The Kolomna design used a typical layout of two crankshafts connected by gearing.

In 1914, the Simpson's Balanced Two-Stroke motorcycle engine was another opposed-piston engine using a single crankshaft beneath the centre of the cylinders with both pistons connected by levers.<ref>{{cite journal |title=A Horizontally Opposed Two-stroke Engine |journal=[[The Motor Cycle]] |date=6 August 1914 |page=204 }}</ref> This engine was a crankcase compression design, with one piston used to uncover the transfer port, and the other to open the exhaust port. The advantage of this design was to avoid the [[deflector piston|deflector crown]]s for pistons used by most two-stroke engines at that time.

[[William Doxford & Sons|Doxford Engine Works]] in the United Kingdom built large opposed-piston engines for marine use, with the first Doxford engine being installed in a ship in 1921.<ref>{{cite web |title=Index Doxford site |url=http://users.telenet.be/doxford-matters/ |website=Telenet.be |access-date=26 November 2019 }}</ref> This diesel engine used a single crankshaft at one end of the cylinders and a crosshead for the opposing piston.<ref name="oldengine1">{{Cite web |url=http://www.oldengine.org/members/diesel/Marine/doxford.htm |title=Marine Engines – Doxford |website=OldEngine.org |archive-url=https://web.archive.org/web/20131202224409/http://www.oldengine.org/members/diesel/Marine/doxford.htm |archive-date=2 December 2013 }}</ref><ref>{{cite web |title=PatOP: Single-Crankshaft Opposed-Piston Engine |url=http://www.pattakon.com/pattakonPatOP.htm |website=Pattakon.com |access-date=29 November 2019 }}</ref> After World War I, these engines were produced in a number of models, such as the P and J series, with outputs as high as {{convert|20000|hp|kW|0|abbr=on}}. Production of Doxford engines in the UK ceased in 1980.<ref name="oldengine1" /><ref>{{Cite web|url=http://www.doxford-engine.com/ |title=Doxford Engines 1878–1980 |website=Doxford-Engine.com |access-date=28 March 2006 |archive-url=https://web.archive.org/web/20161224093713/http://www.doxford-engine.com/ |archive-date=24 December 2016 }}</ref>

Later opposed-piston diesel engines include the 1932 [[Junkers Jumo 205]] aircraft engine built in Germany, which had two crankshafts, not using a design similar to the 1900–1922 Gobron-Brillié engines.<ref>{{cite book |last=Setright |first=L. J. K. |title=Some unusual engines |date=1975 |publisher=Mechanical Engineering Publications for the [[Institution of Mechanical Engineers]]|isbn=9780852982082 |url=https://books.google.com/books?id=pqhTAAAAMAAJ |access-date=20 November 2019 }}</ref>
{{clear right}}

<gallery mode="packed" heights="170px"; style="text-align:left">
File:OechelhäuserEngine.jpg|1898 Oechelhäuser gas engine
File:Gobron engine (Autocar Handbook, Ninth edition).jpg|1900 [[Gobron-Brillié]] opposed-piston engine with overhung yoke
File:Opposed piston engine 1.jpg|[[Fairbanks Morse 38 8-1/8 diesel engine]] on the {{USS|Pampanito|SS-383|6}} submarine
File:The Tank Museum (2383).jpg|[[Leyland L60]] as used in the [[Chieftain tank]]
</gallery>

=== 1940s to present ===
The [[Fairbanks Morse 38 8-1/8 diesel engine]], designed in Germany in the 1930s, was used in U.S. submarines in the 1940s and 1950s, and in boats from the 1930s-present.<ref>{{cite web |title=Fairbanks-Morse 38D8 Diesel Engine |url=http://www.psrm.org/roster/diesel/fm/index.html |website=PSRM.org |archive-url=https://web.archive.org/web/20060526222933/http://www.psrm.org/roster/diesel/fm/index.html |archive-date=26 May 2006 }}</ref> It has been used in locomotives since 1944.

The November 2021 version of the Fairbanks-Morse 38 8-1/8, the FM 38D 8-1/8 Diesel and Dual Fuel, retains the same extra-heavy-duty design and has a rated in-service lifespan of more than 40 years, but now can burn dual fuels (gaseous and liquid fuels, with automatic switchover to full diesel if the gas supply runs out).<ref>{{Cite web |url=https://www.fairbanksmorse.com/38d-8-1/8 |title=Fairbanks-Morse FM 38D 8-1/8 Diesel and Dual Fuel }}</ref>
  
The [[Commer TS3]] three-cylinder diesel truck engines, released in 1954, have a single crankshaft beneath the centre of the cylinders with both pistons connected by levers.<ref name="oldengine2">{{Cite web |url=http://www.oldengine.org/members/diesel/technical/TS3.htm |title=Rootes-Lister – TS3 Horizontally Opposed Piston Engine |website=OldEngine.org |archive-url=https://web.archive.org/web/20080225131409/http://www.oldengine.org/members/diesel/technical/TS3.htm |archive-date=25 February 2008 }}</ref>

[[File:Napier Deltic Animation.gif|thumb|263x263px|Animated diagram of the Napier Deltic]]

Also released in 1954 was the Napier Deltic engine for military boats. It uses three crankshafts, one at each corner, to form the three banks of double-ended cylinders arranged in an equilateral triangle. The Deltic engine was used in [[British Rail Class 55]] and [[British Rail Class 23]] locomotives and to power fast patrol boats and [[Royal Navy]] mine sweepers. Beginning in 1962, Gibbs invited [[Mack Trucks]] to take part in designing FDNY’s super pumper and its companion tender. DeLaval Turbine was commissioned to design a multistage centrifugal pump with a Napier-Deltic T18-37C diesel to power the pumps.<ref>{{Cite web |url=https://www.firerescue1.com/fire-products/fire-apparatus/articles/the-greatest-fire-pumper-the-world-has-known-TrMsI86bXHcXv1iq |title=The Greatest Fire Pumper the World Has Known (Fire Rescue 1) |date=8 January 2016 }}</ref>

In 1959, the [[Leyland L60]] {{convert|19|L|cuin|0|abbr=on}} six-cylinder diesel engine was introduced. The L60 was produced in the United Kingdom for use in the Chieftain tank.<ref name="Achates timeline">{{cite web |website=AchatesPower.com |title=Engine Design Timeline |url=http://www.achatespower.com/engine-design-timeline.php |archive-url=https://web.archive.org/web/20130513130430/http://www.achatespower.com/engine-design-timeline.php |archive-date=13 May 2013 }}</ref> 

The Soviet [[T-64]] tank, produced from 1963–1987, also used an opposed-piston diesel engine {{Not translated|5TD|uk|5ТД}} developed by [[Malyshev Factory]] in Kharkiv. After the [[dissolution of the Soviet Union]] Malyshev Factory continued development and production of opposed-piston engines for armored vehicles, such as the three-cylinder {{Not translated|3TD|uk|3ТД}} used in [[BTR-4|BTR-4 Butsefal]], various upgrades of the 5TD and the six-cylinder {{Not translated|6TD|uk|6ТД}} for T-64BM2, [[BM Oplot]] etc.

In 2014, [[Achates Power]] published a technical paper citing a 30% fuel economy improvement when its engine was benchmarked against a next-generation diesel engine equipped with advanced technologies.<ref name="Achates timeline" />

[[Volvo]] filed for a patent in 2017.<ref>{{Cite web |url=https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=2017122199A1&KC=A1&FT=D&ND=3&date=20170504&DB=&locale=en_EP# |title=Two-stroke Opposed Piston Internal Combustion Engine |website=[[Espacenet]] |access-date= 20 November 2019 }}</ref>

The [[Diesel Air Dair 100]] is a two-cylinder {{convert|100|hp|kW|0|abbr=on}} [[diesel engine|diesel]] [[aircraft engine]], designed and produced by Diesel Air Ltd of [[Olney, Buckinghamshire]] for use in [[airship]]s, [[home-built aircraft|home-built]] [[kitplane]]s, and [[light aircraft]].<ref>{{cite press release |title=Diesel Air pamphlet |location=Olney, Buckinghamshire, United Kingdom |publisher=Diesel Air |date=2002 }}</ref>

In July 2021, [[Cummins]] was awarded an $87M contract by the [[United States Army]] to complete the development of the Advanced Combat Engine (ACE), a modular and scalable diesel engine solution that uses opposed-piston technology.<ref>{{Cite web |url=https://www.cummins.com/news/releases/2021/07/30/us-army-awards-cummins-inc-87m-contract-deliver-advanced-combat-engine |title=U.S. Army Awards Cummins Inc. $87M Contract to Deliver the Advanced Combat Engine |website=[[Cummins]] }}</ref>