Investigation of diesel/n-butanol blends as drop-in fuel for heavy-duty diesel engines: Combustion, performance, and emissions

This study focused on the application of a single-zone combustion model together with triple Wiebe functions to analyze the impact of the diesel/n-butanol blends as drop-in fuel in a four-cylinder heavy-duty diesel engine (HDDE). Commercial diesel (EN590) was used as a reference fuel to compare combustion, performance, and emissions characteristics with n-butanol blends of 5%, 10%, and 20%, by volume (DBu5, DBu10, and DBu20) under different speed and load conditions as per the World Harmonized Steady-State Cycle (WHSC). The apparent heat release rate (AHRR) calculated from the model agrees (RMSE & LE; 6.80) with the experimental values. The results show that the DBu5 and DBu10 blend increase maximum in-cylinder pressure and maximum AHRR while the in-cylinder temperature slightly decreases, at low load, without significant changes in ignition delay and combustion duration. The DBu20 blend reduced maximum in-cylinder pressure, maximum AHRR and in-cylinder temperature in all operating conditions, in addition, increased the ignition delay and reduced the combustion duration. Brake specific fuel consumption (BSFC) increases by 0.8-6% with an increase in n-butanol content; however, the addition of n-butanol reduced the brake specific energy consumption (BSEC) by 1.7-2.3%. All n-butanol blends reduced CO and particle emissions, regardless of operating conditions, while THC and NOX emissions increased mainly at full load. DBu10 blend showed better engine performance along with combustion and emission characteristics, which makes it a promising fuel blend as per the current study.