Effects of CO ₂ and N ₂ Dilutions on Laminar and Turbulent Flame Propagation

EGR (Exhaust Gas Recirculation) is adopted to reduce NO_x emission in spark ignition engines. The effects of dilution with CO₂ and N₂, the main components of EGR, on laminar flame were investigated. It had been found that CO₂ and N₂ dilutions affected not only laminar burning velocity but also the response of flame to the flame stretch due to the change in the thermo-diffusive properties of the mixtures by the dilutions. Thus, turbulent flames were also investigated at fixed flame stretch factors to examine solely the thermo-diffusive effects on turbulent flame.