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Investigation of the end-gas autoignition process in natural gas engines and evaluation of the methane number index

Journal Article · · Proceedings of the Combustion Institute
 [1];  [2];  [3];  [2];  [2];  [2]
  1. Colorado State Univ., Fort Collins, CO (United States); Colorado State University
  2. Colorado State Univ., Fort Collins, CO (United States)
  3. Cummins Inc., Columbus, IN (United States)
+ Show Author Affiliations
Engine knock and misfire are barriers to pathways leading to high-efficiency Spark-Ignited (SI) Natural Gas (NG) engines. The general tendency to knock is highly dependent on engine operating conditions and the fuel reactivity. The problem is further complicated by the wide range of chemical reactivity in pipeline quality NG, represented by the Methane Number (MN) (65< MN<95). Understanding the underlying phenomena responsible for engine knock can support the development of predictive tools capable of identifying knock onset/intensity as well as a fuel’s propensity to knock, allowing engine manufacturers to expand the knock envelope and design more efficient/robust SI NG engines. Additionally, there is an opportunity for increased efficiency by controlling levels of end-gas autoignition if this can be predicted and controlled. This work focuses on the development of a novel methodology to understand/predict a fuel’s propensity to knock. This methodology is based on the charge fraction undergoing autoignition, namely fractional end-gas autoignition (F-EGAI), and was developed based on first order laminar flame speeds and ignition delay analysis combined with a 0-D homogeneous batch reactor model. This methodology proved to be suitable to predict a fuel’s propensity to knock, even under conditions when light knock was observed. The simple modeling approach was used to explain the results from a series of MN tests with multiple NG compositions exhibiting a wide range of reactivity compositions and providing insight on why fuels of very different chemical compositions can have the same MN. Finally, a CFD model was developed was used to confirm the methodology capability and provide further insights in the physical and chemical phenomena behind end gas autoignition.
Research Organization:
Colorado State Univ., Fort Collins, CO (United States)
Sponsoring Organization:
USDOE; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Vehicle Technologies Office
Grant/Contract Number:
EE0008331
OSTI ID:
1778847
Alternate ID(s):
OSTI ID: 1777050
Journal Information:
Proceedings of the Combustion Institute, Journal Name: Proceedings of the Combustion Institute Journal Issue: 4 Vol. 38; ISSN 1540-7489
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (4)

An experimental and chemical kinetic modeling study of 1,3-butadiene combustion: Ignition delay time and laminar flame speed measurements journal November 2018
The estimation of knock-points of fuels by a weighted mean square error criterion journal September 2006
Calculation of Laminar Flame Speed and Autoignition Delay at High Temperature and Pressures
  • Xu, Hui; LaPointe, Leon A.
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conference February 2014
Effect of Gas Composition on Octane Number of Natural Gas Fuels
  • Kubesh, John; King, Steven R.; Liss, William E.
  • International Fuels & Lubricants Meeting & Exposition, SAE Technical Paper Series https://doi.org/10.4271/922359
conference October 1992

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Related Subjects

42 ENGINEERING
CFD
End gas auto ignition
Engine knock
Methane number
Natural gas