Size impact of cerium oxide nanoparticles (CeO2) on ternary fuel blend using third-generation biodiesel in VCR diesel engine

An experiment was conducted to examine the impact of blending third-generation biodiesel waste cooking biodiesel (WCO biodiesel) and Azolla pinnata microalgae biodiesel (APO biodiesel) with cerium oxide nanoparticles (CeO2 NPs) at 40 ppm concentration, encompassing sizes of 20, 50, and 100 nm. These biodiesels were generated via methanol-KOH trans-esterification. The investigation was carried out on a Kirloskar TV1 single-cylinder four-stroke variable compression ratio (VCR) diesel engine across load variations (0-100%) and compression ratios (i.e., CRs 16, 17, and 18) at a consistent 1500 rpm engine speed. Among various test fuel blends, D80W10A10CNP50 (Diesel 80% + WCO 10% + APO 10% + 40 ppm CeO2 50 nm) yielded optimized results across all conditions. Incorporating CeO2 NPs boosted brake thermal efficiency (BTE) by reducing brake-specific energy consumption (BSEC), and it facilitated efficient combustion as a catalyst, leading to decreased emissions. NP size notably influenced these enhancements. Specifically, employing 50 nm NPs yielded optimal performance parameters and reduced exhaust emissions across all CRs. At CR-17, as compared to additive-free D80W10A10, the fuel formulation, including 50 nm NPs, resulted in an 11.1% BTE increase and a 6.03% BSEC decrease. Also, emission parameters revealed that carbon monoxide (CO), unburnt hydrocarbons (UBHC), nitrogen oxides (NOX), and smoke opacity decreased by 30.76%, 25.44%, 9.12%, and 13.64%, respectively, while carbon dioxide (CO2) emissions increased by 10.09%. These results may help elucidate the chemical mechanism of action of NPs and open the way for developing a more effective fuel additive.