Investigations for the optimal combination of zinc oxide nanoparticle-diesel fuel with optimal compression ratio for improving performance and reducing the emission features of variable compression ratio diesel engine

The continual hike in environmental pollution from diesel engines has raised the concern of researchers to identify certain clean fuels. For this purpose, experimental investigations are carried out to inspect the consequences of ZnO nanoparticles addition for performance and emissions features of a 4-stroke, single-cylinder diesel engine. ZnO nanoparticles were mixed with pure diesel in varying proportions ranging from 5 to 25 mg. The better dispersion of ZnO nanoparticles in diesel was attained by means of magnetic stirrer and ultrasonication process. The test fuels were experimented at varying engine loads of 2 kW, 4 kW, 6 kW, 8 kW, 10 kW and 12 kW at 1500 rpm engine speed. It was observed that among different test fuels, an enhancement in brake thermal efficiency was achieved by 15.58% and reduction of 11.11% in brake specific fuel consumption for 20ZnO60DF (20 mg ZNP + 20 mg CTAB surfactant + 600 ml diesel) at 12 kW engine load as compared with neat diesel. The toxic emissions of NOX, HC, CO, CO2 and particulate matter with the inclusion of 20ZnO60DF were significantly decreased by 57.46%, 78.78%, 58.93%, 41.85% and 42.51%, respectively, as correlated with pure diesel fuel at 12 kW condition with 18 compression ratio. The recommended optimal combination of ZnO nanoparticle-diesel with optimal compression ratio for better performance and reduced emissions level was found out to be 20ZnO60DF with compression ratio 18. So, it is concluded that ZnO nanoparticles addition to diesel could be accepted as a clean alternative fuel as it emits lesser emissions and acts as environmental-friendly fuel.