Autoignition characterization of primary reference fuels and n-heptane/n-butanol mixtures in a constant volume combustion device and homogeneous charge compression ignition engine
KAUST DepartmentClean Combustion Research Center
Physical Sciences and Engineering (PSE) Division
Chemical and Biological Engineering Program
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AbstractIn this study, the autoignition behavior of primary reference fuels (PRF) and blends of n-heptane/n-butanol were examined in a Waukesha Fuel Ignition Tester (FIT) and a Homogeneous Charge Compression Engine (HCCI). Fourteen different blends of iso-octane, n-heptane, and n-butanol were tested in the FIT - 28 test runs with 25 ignition measurements for each test run, totaling 350 individual tests in all. These experimental results supported previous findings that fuel blends with high alcohol content can exhibit very different ignition delay periods than similarly blended reference fuels. The experiments further showed that n-butanol blends behaved unlike PRF blends when comparing the autoignition behavior as a function of the percentage of low reactivity component. The HCCI and FIT experimental results favorably compared against single and multizone models with detailed chemical kinetic mechanisms - both an existing mechanism as well as one developed during this study were used. The experimental and modeling results suggest that that the FIT instrument is a valuable tool for analysis of high pressure, low temperature chemistry, and autoignition for future fuels in advanced combustion engines. Additionally, in both the FIT and engine experiments the fraction of low temperature heat release (fLTHR) was found to correlate very well with the crank angle of maximum heat release and shows promise as a useful metric for fuel reactivity in advanced combustion applications. © 2013 American Chemical Society.
SponsorsThis research was funded in part by the National Science Foundation (grant No. 0801707, an NSF IGERT Program in Multidisciplinary Approaches to Sustainable Bioenergy) and the Colorado Center for Biofuels and Biorefining (C2B2). The authors thank Harrison Bucy and Nathan Pekoc for their technical assistance with the FIT as well as Aaron Gaylord, Michael Herder, Scott Salisbury, Ryan Farah, Ryan Peters, and Nathan Zeleski for their assistance in converting the John Deere 4024T engine to operate in HCCI mode. Co-author S.M.S. acknowledges funding from the Clean Combustion Research Center (CCRC) at KAUST and from Saudi Aramco under the FUELCOM research program.
PublisherAmerican Chemical Society (ACS)
JournalEnergy & Fuels