Exploring The Energetic Efficiency of Internal Combustion Engines: A Comparative Study of Ignited Spark Exergy and Energy Analysis for Hydrogen Fuel, Methane, and Gasoline

Exergy analysis is an invaluable tool used to identify the individual contributions of different processes in transferring input functionality to a system. It allows us to pinpoint exactly where useful energy losses occur within a given system or process. In this particular study, our focus lies on conducting an exergy comparison of the performance of an internal combustion engine with spark-ignition, specifically analyzing the impact of gasoline, hydrogen, and methane fuels. In the study, we have implemented a multi-zone modeling approach to accurately simulate the flame advancement within the engine. By dividing the combustion chamber into different zones, we can capture the complex combustion processes occurring in each zone more effectively. This enables a detailed analysis of the combustion characteristics and their impact on engine performance. Moving on to the exergy analysis, we have laid the necessary conceptual foundations for a comprehensive assessment of the system. Exergy, which represents the maximum useful work that can be obtained from a system, has been defined and quantified. By establishing exergy balance equations and applying them to closed systems and control volumes, we can evaluate the efficiency and effectiveness of energy transfers within the enginee. In this fascinating study, our research delves into the intricate dynamics of engine irreversibility, with a particular focus on the combustion process. Through meticulous analysis, we uncover that the combustion process accounts for the largest share of irreversibility within the engine. It is a pivotal finding that sheds light on the fundamental aspects of engine efficiency. Furthermore, the investigation extends to stoichiometric conditions, where we observe noteworthy trends in exergy transfer across three different fuels. Surprisingly, our results reveal that the percentage of exergy transferred by working is nearly equal for all three fuels considered. However, when examining the percentage of irreversibility, a captivating divergence emerges. Among the fuels investigated, gasoline exhibits the highest percentage of irreversibility, suggesting unique challenges in achieving optimal efficiency. On the other hand, hydrogen, known for its remarkable potential as a clean fuel source, showcases the lowest percentage of irreversibility. This exciting finding highlights the inherent advantages of hydrogen as a fuel for future sustainable technologies. The comprehensive research presented in this study offers invaluable insights into the intricate interplay between combustion, exergy transfer, and irreversibility within the engine. By shedding light on these crucial aspects, we aim to contribute to the ongoing pursuit of enhancing engine efficiency and sustainability. Further analysis of the exergy data obtained under the specified operating conditions, as outlined in the research paper, reveals intriguing trends. By increasing the engine speed, we observe a notable increase in the transfer of exergy with work while the exergy transfer with heat decreases. This suggests that higher engine speeds lead to a more efficient conversion of energy into useful work, with reduced energy losses in the form of heat. Moreover, our investigation demonstrates that manipulating the equivalence ratio has a substantial impact on the distribution of exergy within the cylinder. Specifically, as the equivalence ratio increases, we observe a significant increase in the proportion of exergy stored within the mixture inside the cylinder. This implies that a richer mixture composition enhances the energy content available for conversion into work. Simultaneously, the share of irreversible losses associated with the inlet exergy diminishes as the equivalence ratio rises. This implies that a higher fuel-to-air ratio results in a more efficient utilization of the incoming energy, thereby reducing the extent of energy dissipation as irreversibilities.