Effect of ZnO nanoparticle on combustion and emission characteristics of a diesel engine powered by lemongrass biodiesel: an experimental approach

Biodiesel (BD) is one of the efficient alternative fuels for diesel engines (DE) which can be employed sans any modifications. The present study is focused on the extraction of BD from a lemongrass plant and analyzing combustion, efficiency, and emission characteristics of the DE by adding NPs at different concentrations to reduce both hydrocarbon, carbon monoxide, and NOx emissions simultaneously from the DE. The fuel samples were prepared by adding different dosages of zinc oxide nanoparticles (ZnO NPs) with neat lemongrass biodiesel (LGB) such as 50 ppm, 100 ppm, 150 ppm, 200 ppm, and 250 ppm per liter. From the results, it is found that the properties of BD were improved by the addition of ZnO NPs and it increased oxygen concentration in the sample resulting in better combustion and lower exhaust pollutants. The DE tested with the LGB + 150 ppm sample has registered maximum brake thermal efficiency (BTE) and lower specific fuel combustion (SFC) for all loading conditions compared to other samples. The value of heat release rate (HRR) and in-cylinder pressure are higher for LGB + 150 ppm due to its specific properties compared to other LGB blends. The presence of ZnO NPs in LGB has reduced harmful emissions from the DE such as carbon monoxide (CO), hydrocarbon (HC), oxides of nitrogen (NOx), and smoke by 4.01%, 5.56%, and 19.01%, when compared to neat LGB. The addition of ZnO NPs improves lemongrass biodiesel combustion, boosting engine efficiency. Nano-biodiesel blend achieves superior BTE and lower fuel consumption. ZnO NPs in LGB decrease CO, HC, NOx, and smoke emissions in diesel engines.