Construction of a compact skeletal mechanism for acetone-n-butanol-ethanol (ABE)/diesel blends combustion in engines using a decoupling methodology

Acetone-n-butanol-ethanol (ABE) has proven to be a promising biofuel rather than n-butanol. Although the detailed and semi-detailed oxidation mechanisms of ABE were proposed, they were not suitable in combustion model with an acceptable timescale. Therefore, a skeletal mechanism for ABE/diesel blends combustion was developed hierarchically with the special emphasis on engine-relevant operating conditions using a decoupling methodology. It composes of 82 species and 247 reactions conformed to the combustion characteristics of nine components which are acetone, n-butanol, ethanol, ABE, diesel and four diesel surrogates including methylcyclohexane, iso-octane, toluene and n-decane. The compact-sized mechanism was benefited from acetone, n-butanol, ethanol and diesel surrogates sharing the same detailed core sub-mechanism, and their extremely simplified fuel-related sub-mechanisms. The mechanism was then fully validated against ignition delay, laminar flame speed, premixed flame species profile, and direct injection compression ignition engine combustion. The results show that the measured combustion behavior in experiments are well reproduced, indicating the current mechanism can be reliably applied to predict the ABE/diesel blends combustion in practical engines.