Study of combustion, performance and emissions of diesel engine fueled with diesel/biodiesel/alcohol blends having the same oxygen concentration

Abstract

This experimental study is conducted to investigate the combustion, performance and emissions of a diesel engine fueled with different alternative fuels under five engine loads and at an engine speed of 1800 rpm. Seven fuels, including diesel (D), waste cooking oil biodiesel (B), methanol (M), ethanol (E), 2-propanol (Pr), n-butanol (Bu) and n-pentanol (Pe)) were used to produce six blended fuels, labelled as DB, DBM, DBE, DBPr, DBBu and DBPe. Each blended fuel has the same oxygen content of 5.0% and very close carbon and hydrogen contents and LHV.According to the average results of five loads, the blended fuels in general cause to (a) increases in peak HRR (except DB), ignition delay (except DB), COVIMEP (except DBM), COV Max(dP/dθ) (except DB and DBM) and BSFC; (b) slight decrease in duration of combustion (except DB); and (c) similar peak in-cylinder pressure and BTE (except DBM and DBBu) compared to diesel fuel. Moreover, all the blended fuels lead to reductions in CO2 (except DB), CO, HC, NOX (except DB), PM, total number concentration (except DBPr) and geometric mean diameter, compared to diesel fuel. Overall, DBM shows the highest BTE, the lowest BSFC, and the lowest CO2, CO, HC, PM, NOX (after DBPr), COVIMEP and COV Max(dP/dθ) (after DB), while DB has the lowest influence, among all the tested blended fuels.