An Experimental Investigation on the Characteristics of a Compression Ignition Engine Fuelled by Diesel-Palm Biodiesel–Ethanol/Propanol Based Ternary Blends

Issues such as rising fuel prices, fuel costs, and lowering reserves highlight the importance of research into sustainable fuels derived from biological sources. This study is focused on experiments on a CI engine using ethanol and propanol-based ternary blends. Palm biodiesel is kept constant at 40% volumetric concentration, while diesel and ethanol/propanol are varied in different batches. The results obtained with ternary blends were compared with reference fuel diesel, pure palm biodiesel, and a palm biodiesel–diesel binary blend. The ternary blends exhibit lower brake thermal efficiency and higher brake specific energy consumption than diesel and binary blends due to their lower calorific value. Despite in-fuel oxygen presence, lower brake specific oxides of nitrogen and smoke opacity were observed for engine operation with a ternary blend due to the predominant role of higher latent heat of vaporization and volatility of alcohols, but unburned hydrocarbon and carbon monoxide emissions increased due to the interactive effect of a lower cetane number, higher latent heat of vaporization, and lower kinematic viscosity of alcohols when compared to reference fuels. Among the tested fuels, in-cylinder pressure was observed to decrease with ternary blends due to their lower calorific value, but a raised heat release rate was attributed to lower viscosity and faster burning of alcohols.