A comprehensive study on the influences of different types of nano-sized particles usage in diesel-bioethanol blends on combustion, performance, and environmental aspects

Highlights: • Deeply discussed combustion, performance, and emission characteristics of the CI engine. • Impact of 100 ppm aluminum oxide, and titanium oxide nanoparticles addition in diesel-ethanol blends. • Worsened BSFC, BTE and NO_x emission of the engine fuelled by biofuel-diesel fuel. • Noticed promising results in the presence of nanoparticles in the test fuels. • Pulled back of the worsened engine characteristics arising from biofuel-usage with nanoparticles. This paper aims to discuss the influences of the doping of different types of nanoparticles into the bioethanol-diesel fuel blends on the combustion, performance, and emission aspects. In this viewpoint, the tests are performed at a constant engine speed of 2400 rpm under the varying engine loads from 3 to 12 Nm with the gaps of 3 Nm. Test engine is fuelled with conventional diesel fuel (DF), the binary form of 90% diesel fuel and %10 ethanol (DF90E10), and then separately 100 ppm aluminium oxide (Al₂O₃) nanoparticles (DF90E10 + A100), and 100 ppm titanium oxide (TiO₂) nanoparticles (DF90E10 + T100) into DF90E10 test fuel. In the results, DF90E10 increases brake specific fuel consumption (BSFC) by 6.25% and drops the brake thermal efficiency (BTE) by 2.1% in comparison to those of conventional DF. However, it is noticed that nanoparticles-doped DF90E10 test fuels are being pulled back the worsened performance results thanks to their higher surface to volume ratio, higher cetane number, higher calorific value, superior thermal properties, catalyst role of the accelerating chemical reactions in combustion proces, and high energy density of nanoparticles. Accordingly, BSFC is dropped by 2.25% and 1.26% whilst BTE is enhanced by 3.48% and 2.94% for DF90E10 + A100 and DF90E10 + T100 test fuels, respectively as compared to those of DF. Thanks to the excess oxygen content of ethanol and oxygen-donating catalyst role of nanoparticles, carbon monoxide (CO) is reduced by 14.29%, 25%, and 21.43%, and hydrocarbon (HC) is reduced by 21.32%, 30.15%, and 26.47% for DF90E10, DF90E10 + A100, and DF90E10 + T100, respectively as compared to those of conventional DF. NO_x emission increases by 3.6% for DF90E10, and then nitrogen oxides (NO_x) are reduced by 3.02%, and 1.57% for DF90E10 + A100 and DF90E10 + T100 due to the higher thermal conductivity value of nanoparticles and improving engine performance characteristics. On the other hand, the highest in-cylinder pressure (CP_max) and heat release rate (HRR_max) values, and longer ignition delay are generally noticed for the diesel-ethanol binary blend due to the lower cetane number, lower energy density and higher viscosity. In conclusion, this paper is proving that the doping of nanoparticles into the biofuels is presenting very satisfying results in pulling back the worsened engine characteristics arising from using diesel-biofuel binary blends.