METHOD FOR REGENERATING NOx CATALYST OF NOx PURIFYING SYSTEM AND NOx PURIFYING SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a method for regenerating the NOx catalyst of an NOx purifying system and an NOx purifying system enabling the suppression of discharge of NOx into the atmosphere when exhaust gas is temporarily brought into a rich condition to regenerate a catalyst to recover the NOx purifying ability of a direct reduction type NOx catalyst situated in the exhaust passage of an engine and capable of reliably recovering NOx purifying performance. SOLUTION: In the method for regenerating the NOx catalyst in the NOx purifying system where the direct reduction type NOx catalyst to directly decompose NOx at a lean time and regenerate it at a rich time is situated in an exhaust passage, the control of a rich condition is prohibited when a temperature detected by a catalyst temperature detecting means is in a given temperature range. COPYRIGHT: (C)2004,JPO&NCIPI