Performance, combustion and emission characteristics investigations on a diesel engine fueled with diesel/ ethanol /n-butanol blends

Abstract

In this study, a three-dimensional computational fluid dynamics (CFD) model of a diesel engine cylinder was developed by AVL-Fire software, and a chemical reaction mechanism containing 377 reactions and 81 species was established by the CHEMKIN program. The purpose of this work is to investigate the effect of diesel/ethanol/n-butanol blends on combustion and emission characteristics such as in-cylinder pressure, in-cylinder temperature, brake power, brake thermal efficiency, brake specific fuel consumption, NOx emission, CO emission and soot emission. The results showed that the diesel/ethanol/n-butanol blended fuels reduced the brake power and increased the brake specific fuel consumption of the diesel engine, but improved the brake thermal efficiency. In addition, the blend fuels reduced nitrogen oxides, carbon monoxide, and soot emissions. At 100% load, when the diesel engine fueled with E5N13, E10N5, E10N18, E15N10, E15N18, and E20N10, the brake thermal efficiencies were increased by 2.72%, 2.69%, 4.52%, 4.49%, 5.565%, and 5.53% respectively. However, the brake specific fuel consumption increased by 2.79%–5.84%, and the brake power decreased by 2.76%–5.59%. At 50% load, blended fuels with different mixture ratios reduced nitrogen oxides by 8.39%–21.81%, carbon monoxide by 12.1%–22.91%, and soot by 26.71%–48.59% compared to diesel. This is influenced by a combination of higher oxygen content, lower cetane number and calorific value of ethanol and n-butanol.