Performance and exhaust emissions in a diesel engine fuelled with a blend including ZnO nanoparticles and nano-emulsions

Abstract

A realisation of the need to curtail consumption of fossil fuels with high atmospheric emissions has led researchers to investigate alternatives in recent years. Nano-emulsions (NE) with water suspended at nano-size inside diesel fuel offer better air/fuel blends during the combustion process, creating fuels with higher combustion efficiency and lower emissions. For this study, a nano-emulsion with 12 W% was prepared in a high-speed homogenizer to produce an NE fuel with 26 nm effective droplet diameter, based on optimisation calculations in Design-Expert software. Three doses of zinc oxide (50, 100, and 150 ppm) with average diameters 10 to 30 nm were mixed into prepared nano-emulsion samples. Five fuel blends, Diesel, NE, NE+50 ppm ZnO, NE+100 ppm ZnO, and NE+150 ppm ZnO were then examined for performance and emissions in a four-cylinder Fiat Diesel engine at 1,500 rpm constant speed and 400 bar fuel injection pressure, with a changing operating load. Brake specific fuel consumption (BSFC) was reduced by 16.4% with an increase of 10.2% in thermal efficiency for NE+150 ppm ZnO in comparison with the neat diesel at higher loads of 352.88 kN/m2. CO, NOx, HC, and smoke opacity were also reduced by 18%, 13.2%, 17.1%, and 32.8 %, respectively for NE+150ppm ZnO. This research thus offer direction for the utilisation of ZnO nanoparticles in the reduction of exhaust emissions and fuel consumption, offering both economic and environmental benefits.