Influence of aluminum oxide nanoparticle with different particle sizes on the working attributes of diesel engine fueled with blends of diesel and waste plastic oil

In the present work, an experimental investigation was conducted to study the influence of adding aluminum oxide nanoparticles (Al2O3) with different average particle sizes as additive to blends of diesel and waste plastic oil (WPO) on performance, emission, and combustion attributes of single-cylinder diesel engine operated at a constant speed. Two samples of Al2O3 nanoparticle with average particle sizes of 20 and 100 nm were dispersed into a WPO20 blend containing 20% of WPO and 80% of diesel in the mass fractions of 10 and 20 ppm using ultrasonic stabilization. The experimental recordings revealed a decrease in engine performance and increase in all emission constituents while replacing diesel with WPO20. However, the addition of both 20- and 100-nm-sized Al2O3 nanoparticles into WPO20 was found to enhance the brake thermal efficiency (BTHE) by 12.2 and 8.9% respectively and decrease the brake-specific fuel consumption (BSFC) by 11 and 8% respectively. The emission constituents such as carbon monoxide (CO), hydrocarbons (HC), nitric oxide (NO), and smoke opacity were minimized by the addition of both 20- and 100-nm-sized nanoparticles into WPO20 blend. However, the reduction of emissions was better for 20-nm-sized particles compared with that of 100-nm-sized particles. The combustion attributes such as cylinder pressure, heat release rate (HRR), and rate of pressure rise (RPR) were raised with shortened ignition delay (ID) by the addition of both sized nanoparticles. Overall, the inclusion of 20-nm-sized nanoparticles performs better catalytic activity to enhance the engine output characteristics along with minimum exhaust emissions.