The effect of biodiesel and CeO2 nanoparticle blends on the CRDI diesel engine: a special focus on combustion, particle number, PM2.5 species, organic compound, and gaseous emissions

Abstract

This study aimed to investigate the effect of biodiesel and CeO2 nanoparticles (NPs) blends on organic car- bon (OC) and elemental carbon (EC), organic compounds, size distribution, gaseous emissions, and com- bustion reactivity from a CRDI diesel engine at the steady-state mode. To ensure that gaseous pollutants do not depend on a filter device, the research engine was allowed to operate without a diesel particulate filter. The nano-additive of 20 ppm was included in various biodiesel blends through the ultrasonication process. Experimental results revealed that the addition of biodiesel in CeO2 NP blends significantly improved the in-cylinder pressure and heat released rate (HRR) of the engine. As for the B15C20 fuel, sig- nificant reductions in CO and HC emissions were observed by 32.16% and 45.59%, respectively, with a rise in NOx of 5.97% compared to B0. It was also found that the B0 and B0C20 fuels generate more particles within a diameter size range over 50 nm compared to B10C20 and B15C20 that generate particles of diameter ranging from ∼10 nm to 37 nm. EC-soot was slightly higher compared to OC for all test fuels, which could be explained by the catalytic effect of metals on soot oxidation as a result of the low amount of total PM2.5 mass present. The toxic pollutants such as polycyclic aromatic hydrocarbons (PAHs) and n- alkanes decreases when the ratio of biodiesel increases in CeO2 NPs. This might reduce the effect of can- cer and direct eye irritants that cause an allergic response in humans and animals.