Experimental investigation of performance and emission characteristics of a diesel engine fueled with pyrolytic plastic oil–diesel blends enhanced with Al2O3 and TiO2 nanoparticles

• BTE improvement of 2.65% was observed for PPO 60 D 40 A 150 at 21 N load w.r.t. diesel. • BSFC reduction of 19.25% was noticed for PPO 30 D 70 T 150 at 21 N load w.r.t. diesel. • A significant reduction of CO (46.27%) and NO (71.30%) emissions was found for PPO 15 D 85 T 150 and PPO 60 D 40 T 150 , respectively. • The multiple regression model was statistically significant and capable of properly predicting engine performances and emission characteristics. • Overall, the ANOVA results confirmed the developed of regression model that provides a reliable prediction. The exploration of alternative fuels for internal combustion engines has gained significant attention due to the need to improve engine performance while reducing harmful emissions. In this context, this study investigates the performance and emission characteristics of a Petter diesel engine fueled with blends of pyrolytic plastic oil (PPO), diesel, and metal oxide nanoparticles, namely aluminum oxide (Al 2 O 3 ) and titanium dioxide (TiO 2 ). Fuel blends were prepared using a magnetic stirrer and homogenizer with PPO–diesel volumetric ratios ranging from 0% to 100% in 15% increments. Nanoparticles were added separately at concentrations of 75 ppm and 150 ppm. Experimental results show that the PPO 60 D 40 A 150 blend achieved the highest brake thermal efficiency (BTE) of 23.904% at a load of 40 N, representing an improvement of up to 2.65% compared with neat diesel at 21 N load. The PPO 30 D 70 T 150 blend exhibited the maximum reduction in brake-specific fuel consumption (BSFC) of 19.25% at 21 N load. Furthermore, PPO 15 D 85 T 150 achieved the highest reduction in carbon monoxide (CO) emissions of 46.27% at 30 N load, while PPO 40 D 60 T 150 demonstrated the maximum nitrogen oxide (NO x ) reduction of 71.30% at 40 N load. Al 2 O 3 nanoparticles at 150 ppm primarily improved engine efficiency by increasing BTE, whereas TiO 2 nanoparticles at the same concentration were more effective in reducing BSFC, fuel consumption rate, and exhaust emissions. These results suggest that nanoparticle-enhanced PPO–diesel blends are promising alternative fuels for diesel engines in heavy-duty applications, offering improved performance and lower environmental impact.