Editing Opposed-piston engine (section)

=== 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>