Investigating Engine Performance and Emission Characteristics of a CI Engine Fueled with Waste Fried Oil Blend Containing Butanol, Alumina, and Silver Nanoparticles

The accumulation of waste fried oil (WFO) poses significant environmental challenges, necessitating its effective utilization as an alternative fuel. This study examines the synergistic effects of alumina and silver nanoparticles, as well as butanol, when used as additives in WFO-diesel blends. Multi-criteria decision-making (MCDM) framework was implemented to identify a sustainable alternative fuel to conventional diesel. Our findings reveal that a 5% WFO addition to diesel results in a 4% increase in brake power (BP), 4.3% reduction in brake specific fuel consumption (BSFC), and a 16.8% improvement in brake thermal efficiency (BTE) at 3 kW load compared to pure diesel. The incorporation of nanoparticles further enhanced performance, showing up to 12.9% decrease in BSFC and 28.4% increase in BTE and 3.96% increase in BP for 25 ppm alumina when compared to diesel. While emissions were higher than diesel with WFO alone, nanoparticles mitigated carbon monoxide and hydrocarbons emissions by 27.4% and 16.1%, respectively, for 25 ppm silver. The ternary blend of diesel with 5% WFO and 5% n-butanol significantly improved fuel properties, reducing BSFC by 15.7% and enhancing BP and BTE by 4.09% and 29.2%, respectively, compared to diesel. Although nanoparticle addition to the ternary mix slightly decreased performance parameters, it remained superior to diesel. Applying the AHP-TOPSIS method facilitated the selection of most favorable fuel blend based on properties, performance, and emission parameters. The findings concluded that 5% addition of WFO to a mixture of 90% diesel and 5% n-butanol consistently exhibited lower BSFC and higher BTE across all load conditions, making it the preferred fuel blend.