Performance and emission multi-objective optimization of γ-Al2O3 nanoparticle-enhanced E10 bioethanol–gasoline combustion in spark-ignition engines

Abstract With the increasing demand for green energy, bioethanol is widely recognized as a alternative to fossil fuels in spark-ignition (SI) engines. While aluminum oxide (Al 2​ O 3 ) nanoparticles have been studied with other fuels, this research is the first to investigate the impact of γ-Al 2 ​O 3 ​ nanoparticles on E10 blends at concentrations of 10, 20, and 30 ppm. Experimental tests utilized Response Surface Methodology (RSM) with a D-optimal design to model and optimize engine performance and emissions. Multi-objective optimization identified 2471.87 rpm and 5.88 ppm as the most balanced operating conditions. Results showed that at 20 ppm γ-Al 2 ​O 3 ​, brake torque (BT) and brake power (BP) increased by 7.67% and 6.94%, respectively, while brake specific fuel consumption (BSFC) decreased by 5.91%. Emissions analysis revealed reductions of 14.88% in carbon monoxide (CO) and 5.84% in hydrocarbon (HC) emissions, accompanied by a 5.68% increase in carbon dioxide (CO 2 ​). Nitrogen Oxides (NO x ​) emissions increased by 17.08% at higher engine speeds, consistent with elevated flame temperatures. Exceeding the optimal nanoparticle threshold resulted in a decline in performance and increased pollutant emissions. The findings confirm the potential of alumina nanoparticles to boost combustion efficiency and emission characteristics in SI engines, providing a data-driven framework for optimizing these fuel blends.