Energy and Exergy Analysis of Internal Combustion Engine Performance of Spark Ignition for Gasoline, Methane, and Hydrogen Fuels

Exergy analysis is a tool to determine the share of processes involved in transferring input functionality to the system and where the useful energy loss occurs in a system or process. In this study, an exergy comparison of the performance of an internal combustion engine with spark-ignition for gasoline, hydrogen, and methane fuels is considered. For this purpose, first, multi-zone modeling of the engine based on flame advancement has been introduced. Then, the necessary conceptual bases for performing exergy analysis of the system have been established by defining the term exergy and creating the corresponding exergy balance equations and applying them to closed systems and control volumes. This study shows that the largest share of irreversibility in the engine is related to the combustion process. Also, for stoichiometric conditions, we can mention the percentage of exergy transferred by working approximately equal for all three fuels, the highest percentage of irreversibility for gasoline, and the lowest percentage of irreversibility for hydrogen. Examining the exergy analysis results in the assumed operating conditions mentioned in the paper shows that increasing engine speed increases exergy transfer with work and decreases exergy transfer with heat. Also, increasing the equivalence ratio increases the share of exergy of the mixture inside the cylinder and decreases the irreversible share of inlet exergy.