Patent ID: 6630115
Filing Date: 2003-10-07
Classification: B01D,B01J

Abstract:
An internal combustion engine exhaust gas purification process, which comprises(i) contacting an exhaust gas emitted from a lean-burn operated internal combustion engine with an exhaust gas purification catalyst placed in a flow route of the exhaust gas to capture NOx contained in the lean-burn exhaust gas, thereby purifying the exhaust gas by reduction of the captured NOx with reducing components contained in the exhaust gas; and (ii) temporarily shifting the internal combustion engine from the lean-burn operation to a stoichiometric air/fuel ratio operation or a fuel excess operation, thereby reducing the NOx captured by the exhaust gas purification catalyst without subjecting to reduction during the lean-burn operation with the reducing components contained in the stoichiometric or fuel-rich exhaust gas so as to regenerate the exhaust gas purification catalyst, said catalyst comprising a porous carrier and active components supported on the porous carrier, the active component comprising (a) at least one member selected from the group consisting of Rh, Pt and Pd; (b) at least one member selected from the group consisting of alkali metals and alkaline earth metals; and (c) Mn.