Effects of Fuel and Diluents on Stratified Charge Turbulent Combustion in Simplified Conditions

Stratified charge combustion system is widely used for production engines due to the significant potentials, such as low fuel consumption rate and low exhaust gas emissions. The combustion phenomena in simplified stratified charge conditions have been examined with changing the initial turbulence intensity, degree of mixture charge stratification, and kinds of fuels in order to clarify the features. Moreover, it should be noted that the stratified charge combustion may cause raising NOx formation. EGR (Exhaust Gas Recirculation) system is widely used for this solution. In this study, EGR was simulated by using dilution gases, such as CO₂ and N₂. Combustion characteristics in homogeneous and stratified charge fields with dilution gas were examined. As a result, some interesting combustion characteristics between CO₂ and N₂ depending on the specific heat, initial turbulence intensity, and degree of charge stratification were found.