An experimental investigation on enhancing diesel engine performance and emissions with cashew nut shell oil biodiesel and hydrogen fumigation

The study examines the characteristics of a diesel engine that is fuelled by cashew nutshell oil (CNSO) biodiesel as well as hydrogen (H₂) gas. It aims to investigate their synergistic effect and determine optimal blends of fuel and H₂ flow rates to ensure enhanced efficiency and less emission. This study utilized a diesel engine to test different fuels (Diesel, 50CNSO50D, CNSO) and H₂ addition with 3 LPM and 6 LPM flows. The study found that CNSO had 2.17% lower cylinder pressures, the addition of H₂ enhanced combustion by increasing the pressure by 8.56% and the heat release rates (HRR) by 32.40% than diesel. Brake thermal efficiency (BTE) is improved by up to 4.4% with CNSO biodiesel and H₂ supplementation. Analyses of emissions revealed lowering of carbon monoxide (CO) by 25%, hydrocarbon (HC) by 53.33% and carbon dioxide (CO₂) by 14.47% in the combination of CNSO and H₂. These reductions are significant as they indicate a decrease in harmful emissions. However, oxides of nitrogen (NOx) emissions rose by 23.88% with pure CNSO biodiesel. It increased further to 15.4% with the addition of H₂. The work introduces a novel approach of blending CNSO biodiesel, an underutilized sustainable resource, with hydrogen gas for diesel engines, providing fresh insights into their combined impact on engine performance and emissions.