Exergy-based Analysis of Diesel Engine when fuelled with Fossil Diesel and Palm Methyl Ester (PME)

Abstract

Abstract Biomass-based energy sources as an alternative to conventional fossil fuel have gained public attention due to the increasing rate of environmental pollutions and depletion of fossil energy source. For diesel engines, comparisons on fuel sustainability and First Law of Thermodynamics are common to inspect biodiesel’s potential in replacing conventional diesel fuel. However, the present work focuses on the energetic and exergetic comparisons of a light-duty diesel engine fuelled with fossil diesel and neat Palm Methyl Ester (PME). This study also covers emission characteristics and exergy destruction rate under varying engine operating parameters and fuel types. It was revealed that the best engine thermal efficiency when fuelled with fossil diesel and PME are 22.1% (2750 rpm, 1950W) and 24.3% (3000 rpm, 2400W), respectively. Additionally, the exergy efficiencies of the diesel engine at the same operating conditions appear to be approximately 2% lower than their First Law counterparts. This can be attributed to the generation of the entropy in reactions which destroyed the fuels’ potential. The availability destroyed rates were observed to have significant impacts on the exergy efficiencies of the diesel engine. Thus, heat transfer and exhaust exergy rates were investigated since they are the main factors for this outcome. In general, the use of PME fuel will be more beneficial in terms of exergy destruction, engine’s thermal and exergy efficiencies due to its higher oxygen content which improves the fuel combustion process.