METHOD OF DESULFURIZING NITROGEN OXIDE STORAGE CATALYST

PROBLEM TO BE SOLVED: To provide a method of desulfurizing a storage catalyst capable of performing without complicated control and preventing damages of the storage catalyst caused by the excessive high temperature in the desulfurization. SOLUTION: The nitrogen oxide storage catalyst contains preserved nitrogen oxides and sulfur oxides, and is a component of the exhaust gas purification system of a lean combustion engine. That method contains the processes as follows. (1) the process to raise the temperature of the catalyst until the temperature to start the thermal desorption of the nitrogen oxide, and (2) the process to concentrate air/fuel mixture, and the process where the concentration starts at the time of starting of the thermal desorption, and the thermal desorption actuates as a signal to start the concentration, and sets off the desulfurization of the nitrogen oxide storage catalyst. COPYRIGHT: (C)2004,JPO