Thermodynamics based modeling of various in-cylinder processes and spark ignition engine cycle with a focus on sub-models assessment

The utilization of thermodynamics-based modeling emerged as a valuable technique to simulate various complex phenomena and their interactions occurring in a thermodynamic system. This paper presents a thermodynamics-based modeling approach aimed at simplifying the understanding and simulation of various in-cylinder phenomena in spark ignition engines. These phenomena include gas exchange, compression and expansion processes, heat transfer from cylinder walls, combustion, emission formation, mixture composition, properties calculation and frictional losses, which collectively impact the overall engine performance. The paper begins with a brief description of these in-cylinder phenomena and their effects on engine performance, and then thermodynamics-based sub-models and their validations are presented. For a more realistic assessment of engine performance, these sub-models are integrated, and full engine cycle simulations under different operating conditions are carried out. The developed model showed that the simulation results are in close agreement with the experimental results, which ensures that the insights gained from these simulations are trustworthy and can be used effectively for research purposes.