The termomechanical analysis and the CFD Simulation of an SI engine to investigate the effects of piston bowl on engine performance and the pollutant emissions

In this research, the thermomechanical analysis and the CFD simulation of a four cylinders natural aspirated Spark Ignition (SI) engine has been carried out in order to investigate the effects of piston bowl on engine performance and the pollutant emissions of the engine. For this purpose, the effects of the entire stresses on the piston have been studied by classify them into two categories including thermal and mechanical stresses. The thermal stresses, that include the thermal changes due to the combustion process and the heat transfer, as well as the mechanical stresses, that include the pressure due to combustion and inertia, have been analyzed and calculated by applying the superposition principle. In addition, after validation between the baseline engine and the experimental results, the important parameters on velocity contours, the oxides of nitrogen (NOx) and carbon monoxide (CO) have been studied in the two proposed sketch of piston bowl beside the baseline case.