Distribution evolution of intake and residual gas species during CO2 stratification combustion in diesel engine

Abstract Exhaust gas recirculation (EGR) stratification contributes to simultaneous reduction of NO x and smoke emissions. For better understanding and management of EGR stratification, the distribution and evolution of intake and residual gas species inside diesel engine are investigated with numerical simulations. The simulations were initialized with the measured values of CO 2 stratification experiments that were conducted on a heavy duty diesel engine by supplying CO 2 to the tangential intake port only with different CO 2 mass flow rate. The local and global distributions of O 2 , residual CO 2 and intake CO 2 in engine cylinder are expressed by mass concentration contours and global inhomogeneity respectively in this paper. As providing in global distribution cumulative curves and local visual information, the inhomogeneity of residual CO 2 is higher than O 2 and intake CO 2 , which indicates that significant in-cylinder CO 2 stratification will be obtained by trapping more exhaust gas rather than supplying CO 2 to the tangential intake port only. The distribution of O 2 is almost homogeneous in both local and global information, which indicates that supplying CO 2 to one intake port does not destroy O 2 uniformity.