Numerical Investigation of a Potential of Dedicated EGR System for Increasing Thermal Efficiency of SI Engines Fueled with Methane and Propane

This study tried to find a potential of dedicated EGR (d-EGR) system added to the four-cylinder spark ignition (SI) engine to decrease heat loss (Q_heatloss) and improve thermal efficiency (η_th). Test fuels were chosen by methane and propane. PREMIX code in CHEMKIN-PRO was employed to calculate laminar burning velocity (S_L) and flame temperature (T_f). Wiebe function and Wocshni's heat transfer coefficient were considered to calculate η_th. The results show that the d-EGR system increased η_th and it was higher than that of stoichiometric combustion of conventional SI engines due to the low T_f and fast S_L.