Close-coupled SCR system

摘要

A system for treating exhaust gases from a combustion engine and a method for using the same results in improved NOx conversion during engine startup. The system includes a compact SCR flow-through monolith (20) installed upstream of a close- coupled SCR wall-flow filter (22), wherein the compact SCR flow-through monolith may be extruded or made of a thin-walled substrate, such that the SCR flow- through monolith has a smaller volume with lower heat capacity and higher catalyst loading relative to the SCR wall-flow filter.