Patent ID: 7107763

Claim:
A ceramic honeycomb filter comprising a ceramic honeycomb structure having porous partition walls defining a plurality of flow paths which have an exhaust gas inlet side with an exhaust gas inlet opening and an exhaust gas outlet side with an exhaust gas outlet opening, wit plugs inside the flow paths such that an exhaust gas passes through pores of the porous partition walls, thereby removing particulates from the exhaust gas; a catalyst being carried at least partially on the partition walls, on the plugs or on the partition walls and the plugs; wherein a plurality of the plugs at the exhaust gas inlet side are disposed at a position separate from the exhaust gas inlet opening of the flow paths, where the plugs so disposed have a front end surface which faces the exhaust gas inlet opening, at a position at which the temperature will be elevated substantially equal to or higher than the lowest activation temperature of the catalyst at least for a certain period of time during operation of an internal combustion engine, wherein of the total number of plugs at the exhaust gas inlet side 70% or more by number of the plugs at the exhaust gas inlet side are disposed at a position physically separate from the exhaust gas inlet opening of the flow paths along the direction of the flow paths, wherein front end surfaces of the inlet-side plugs are positioned in a region of 0.7 times the entire length of to ceramic honeycomb filter or less from an exhaust gas inlet-side opening end of the ceramic honeycomb filter.