Effect of Different Chamber Geometries on Combustion Formation to Reduce Harmful Emissions

Abstract

The combustion process in internal combustion engines is the primary aspect of engine performance and emissions. Combustion chamber geometries such as grooved combustion chamber (GCC), shallow depth combustion chamber (SCC), and bathtub combustion chamber (BTCC) are used to investigate the effect of combustion rates on the emission parameters with respect to the standard flat combustion chamber (FCC). The impact of chamber modifications was simulated with an IC engine model using advanced chemical kinetics. Combustion parameters such as in-cylinder temperature, turbulence, and heat release rates were observed. The validated computational model assisted in analyzing combustion formations and their correlation with emissions like mass fractions, CO, CO2, and NOx. The results revealed that the modified chambers avoided the formation of fuel pockets and improved combustion behaviour compared to FCC. At 440 oCA, peak NOx emissions were higher by 14.95%, 27.10%, and 15.89% for GCC, SCC, and BTCC chambers, respectively, compared to the FCC chamber. At 440 oCA, CO2 emissions increased by 2.22%, 2.78%, and 2.78% for GCC, SCC, and BTCC chambers, respectively, compared to the FCC. The GCC chamber's geometry influences the air–fuel mixture distribution, leading to stratified combustion zones and utilizing both bowl and squish regions. The study concludes that GCC chambers can significantly enhance efficiency and reduce emissions by influencing temperature profiles and mass fraction distributions. The study recommends using the GCC chamber with optimized injection profiles for better combustion and improved swirl rates.