Enhancing performance characteristics of biodiesel-alcohol/diesel blends with hydrogen and graphene nanoplatelets in a diesel engine

The pursuit of ecologically friendly and sustainable energy solutions is currently at the forefront of scientific study and technological advancements. The replacement of fossil fuels is a serious challenge in diesel engines. Furthermore, several researchers are concerned about lower-rate hydrogen enrichment and NOx emissions. In the current study, 50 mg/l of graphene nanoplatelets (G) and 10% of n-Butanol are used as additives in sterculia foetida biodiesel-diesel blends, along with H2 supply (at a flow rate of 3 and 6 lpm) as a secondary fuel, to improve the overall performance and reduce emissions of a single-cylinder, four-stroke, compression ignition engine. The combination of 20% biodiesel is blended in 80% diesel (B20), 50 mg/l of G included B20 (B20G50), 10 vol % of n-Butanol (on a volume basis) added in B20G50 blend (B20G50+n-Bu10) are used as piloted fuel. Besides, hydrogen enriched with air as a secondary fuel and B20G50+n-Bu10 fuel blend supplied as piloted fuel (B20G50+n-Bu10+3H2, and B20G50+n-Bu10%+6H2) are fueled to determine the performance, combustion, and emission characteristics of a CI engine. The addition of G and n-butanol in a B20 blend with a higher flow rate of H2 enrichment improved performance (Brake thermal efficiency increased by 7.54%, and Brake specific fuel consumption decreased by 20.75%). In contrast, the combustion parameters such as cylinder pressure and Heat release rate are improved by 9.8 and 6.23% at 100% load for the same blend. In contrast, emission characteristics of Carbon monoxide, Hydrocarbons, and smoke opacity are lowered by 19.75, 24.86, 9.58, and 8.8%, respectively, at higher loads as compared to the B20 blend. The higher heating value, improved atomization characteristics, superior flame velocity of H2, greater thermal diffusivity, the catalytic effect of nanoplatelets, and higher oxygen level of n-butanol improved engine performance, combustion, and decreased emission characteristics on diesel engines with no engine modifications. The outcomes of this research may be beneficial to run stationary engines used in various industrial sectors.