Patent ID: 6655128
Filing Date: 2003-12-02
Classification: F01N,Y02T

Abstract:
A method of purging a lean NOx trap that has a matrix (16) of narrow flow passages and is arranged in the exhaust system of a lean burn engine, the method comprising the steps of providing a flow straightening matrix (12) of narrow flow passages preceding the NOx trap matrix (16) and separated from the NOx trap matrix by a narrow chamber (14), and periodically injecting reducing gases in bursts into the narrow chamber (14), each burst having sufficient mass and flow rate to fill the narrow chamber (14) with the reducing gases and to displace the exhaust gases previously present in the narrow chamber (14) into the narrow flow passages of the flow straightening matrix (12) and of the trap (16) without significantly mixing with the exhaust gases previously present in the narrow chamber.