Patent ID: 7763222

Claim:
An exhaust gas purifying system comprising: a first oxidation catalytic member carrying oxidation catalyst containing at least one metal selected from platinum and palladium, and ceria; a honeycomb filter including a porous partition wall having a number of pores arranged so that a plurality of cells communicating between two end faces are formed, and a plugging portion disposed in either of the end faces or inside the cell so as to plug the cell; a second oxidation catalytic member carrying oxidation catalyst containing at least one metal selected from platinum and palladium, and ceria; and a NOx purifying catalytic member including a honeycomb catalyst carrier having substantially same shape as the honeycomb filter, and a NOx purifying catalyst carried on surface of the partition wall or on surface of the pores, wherein the first oxidation catalytic member, the honeycomb filter, the second oxidation catalytic member, and the NOx purifying catalytic member are disposed in this order in an exhaust gas flow path where exhaust gas discharged from a diesel engine circulates, wherein when the NOx purifying catalyst is the NOx selective reducing SCR catalyst, a first supply part capable of jetting and supplying an urea aqueous solution or ammonia aqueous solution is further provided upstream the NOx purifying catalytic member in the exhaust gas flow path, and a second supply part capable of jetting and supplying an urea aqueous solution or ammonia aqueous solution is further provided upstream the honeycomb filter in the exhaust gas flow path, and wherein cell density of the honeycomb catalyst carrier is 12.4 to 93.0 cells/cm 2 , and thickness of the partition wall is 0.1 to 0.508 mm, and in the condition that NOx purifying catalyst is carried, the partition wall of the NOx purifying catalytic member has mean pore size of 20 to 65 μm, porosity of 40 to 70%, and common logarithm standard deviation of pore size distribution of 0.1 to 0.6.