reactivity controlled compression ignition

{{short description|Form of internal combustion}}

Reactivity controlled compression ignition (RCCI) is a form of internal combustion developed at the Engine Research Center, University of Wisconsin–Madison, United States, by the research group of Wisconsin Distinguished Professor Rolf Reitz.{{cite journal |last1=Kokjohn |first1=S L |last2=Hanson |first2=R M |last3=Splitter |first3=D A |last4=Reitz |first4=R D |title=Fuel reactivity controlled compression ignition (RCCI): a pathway to controlled high-efficiency clean combustion |journal=International Journal of Engine Research |date=22 June 2011 |volume=12 |issue=3 |pages=209–226 |doi=10.1177/1468087411401548 |doi-access=free }}

During RCCI combustion,{{cite journal |last1=Reitz |first1=Rolf D. |last2=Duraisamy |first2=Ganesh |title=Review of high efficiency and clean reactivity controlled compression ignition (RCCI) combustion in internal combustion engines |journal=Progress in Energy and Combustion Science |date=February 2015 |volume=46 |pages=12–71 |doi=10.1016/j.pecs.2014.05.003 |doi-access=free }} well-mixed low-reactivity fuel and oxidizer (typically air) are compressed but not reaching auto-ignition. Later, still during compression cycle, high-reactivity fuel is injected to form a local mixture of low- and high-reactivity fuel. Finally the whole fuel charge is ignited near top dead center of the piston by injection of high-reactivity fuel. The RCCI combustion process requires two different fuels. Low-reactivity fuel gets injected into the intake ports with low pressure during the intake stroke. High-reactivity fuel gets injected into the cylinder with high pressure at the end of compression stroke. A throttle characteristic to Otto engines is not needed. Because of compression ignition and lack of throttle control, RCCI resembles much the diesel process. The dual-fuel RCCI can produce ultra-low NOx and soot emissions and higher thermal efficiency compared to conventional diesel combustion.{{Cite journal|last=Paykani|first=Amin|last2=Kakaee|first2=Amir-Hasan|last3=Rahnama|first3=Pourya|last4=Reitz|first4=Rolf D|date=2016-06-01|title=Progress and recent trends in reactivity-controlled compression ignition engines|url=https://doi.org/10.1177/1468087415593013|journal=International Journal of Engine Research|language=en|volume=17|issue=5|pages=481–524|doi=10.1177/1468087415593013|issn=1468-0874|url-access=subscription}}

RCCI patents are controlled by University of Wisconsin–Madison’s Wisconsin Alumni Research Foundation (WARF).{{Cite web | url=https://www.warf.org/for-uw-inventors/inventor-profiles/rolf-reitz/fuel-mixture-technology-revolutionizes-engine-performance.cmsx | title=Fuel-mixture technology revolutionizes engine performance - WARF}} Several derivative ideas have also been experimented with by Caterpillar.{{Cite patent|number=US20150285178A1|title=Reactivity controlled compression ignition engine and method of combustion phasing control|gdate=2015-10-08|invent1=John|inventor1-first=Bobby|url=https://patents.google.com/patent/US20150285178/en}}{{Cite patent|number=US9151241B2|title=Reactivity controlled compression ignition engine operating on a Miller cycle with low pressure loop exhaust gas recirculation system and method|gdate=2015-10-06|invent1=Gehrke|invent2=Fiveland|inventor1-first=Christopher R.|inventor2-first=Scott B.|url=https://patents.google.com/patent/US9151241B2/en?q=(~patent/US20150285178A1)}}