Engine performance and emission analysis of optimized biodiesel produced from tobacco seed oil utilizing Al2O3-CuO hybrid nano additives

• Biodiesel derived from tobacco seed oil has been optimized by response surface methodology. • The yield of the biodiesel has reached maximum to 95.58 ± 0.43% compared to the predicted 95.689% • Biodiesel blends with higher nano-additives degrade rapidly compared to reduced nano additive. • B15 blend has improved 59.27% in BTE and lowered 36.7% fuel consumption compared to diesel. • B10 blend reduced 2.97% NOx emissions with enhanced torque and brake power. • Both performance and environmental effects have improved by incorporating hybrid nano additives. The growing concern regarding energy security and climate change demands biodiesels with enhanced effectiveness and reduced emissions. This research optimizes the production of biodiesel from tobacco seed oil utilizing the Box-Behnken design of Response Surface Methodology and assess the effects of hybrid nanoparticles of Al 2 O 3 and CuO on engine performance, emissions, and fuel stability. Optimal transesterification parameters − methanol to oil molar ratio of 6.818:1, temperature of 54.11°C, reaction time of 86.991 min and catalyst concentration of 0.368 wt% − have produced biodiesel yield of 95.58 ± 0.43% compared to the predicted 95.689%. Biodiesel blends, have demonstrated superior performance characteristics, with higher concentrations of nano additives degrade rapidly after a few months, whereas, blends with reduced nano additive levels exhibit superior stability for long period. The B10 blend significantly enhance torque and break power by 2.35% and 2.36%. B15 obtained a 59.27% increase in BTE and 36.7% lower fuel consumption, outperforming diesel at high speeds of 2500 rpm. B15 decreases CO emissions by 76.75% and B10 reduces NOx emissions by 2.97%. Although hybrid nano additives have limited influence on engine performance, emissions characteristics have enhanced significantly. The B15AC100 blend exhibited the highest overall emission reduction of 73.57% in CO, 11.63% in CO 2 , 76.10% in HC, and 7.49% in NOx emissions. Results indicate that the blends of tobacco seed biodiesel with hybrid nano additives reduce environmental issues and maintain performance for sustainable fuel development.