Exergy analysis of a water cooled single cylinder dual fuel engine fueled with diesel-ethanol under different ethanol energy ratio

Diesel-ethanol dual-fuel combustion has been recognized as an effective alternative to improve efficiency, reduce emissions and substitute part of the fossil fuel. In this regard, the need to improve engine efficiency has continued to drive studies through the understanding of the engine’s thermodynamics. However, the energy analysis based on the first law of thermodynamics does not identify and quantify the system inefficiencies, being insufficient to reveal the best efficiencies of any system. Therefore, the exergy analysis based on the second law of thermodynamics is required to understand and improve the actual efficiencies of the entire system and has higher research significance. Exergy analysis in recent years has been widely used in various thermal systems. A significant number of exergy studies was published for several types of thermal systems, but the number of studies on internal combustion engines is relatively low, especially when it deals with to the dual-fuel mode with diesel and ethanol. In this paper, the exergy analysis of a dual-fuel engine fueled with diesel and ethanol has been investigated. Hydrous ethanol was injected at the engine intake manifold. Thermodynamics analysis was performed using experimental data for a single cylinder engine operating at full load at 3000 rpm, and ethanol energy ratios between 12.4% to 50.7%. It has been found that diesel ethanol dual-fuel combustion has lower exergy loss in relation to conventional diesel combustion. The exergy loss in the exhaust gases of diesel-ethanol operation mode is also reduced compared to pure diesel fuel for all ethanol energy ratios. The results also indicated an increase in second law efficiency as the ethanol energy ratio increases. The maximum exergy efficiency achieved was 33.4% to 12.4% of the ethanol energy ratio. The exergy destruction and entropy production were reduced when ethanol energy ratio increases.