Patent ID: 7073327

Claim:
An exhaust emission control system comprising: an internal combustion engine; a filter for capturing particulate matters in an exhaust gas exhausted from the internal combustion engine; and an exhaust pipe for introducing the exhaust gas into the filter, the system comprising combustion means for intermittently burning the particulate matters captured by the filter, the filter being a honeycomb filter including: at least two end faces; porous partition walls extending from one end face to the other end face; and a large number of through channels partitioned by the partition walls and extending from one end face through the other end face, predetermined through channels being sealed in one end face, remaining predetermined through channels being sealed in the other end face, wherein assuming that a partition wall thickness is (X) Î¼m, and the number of through channels per unit area in a section vertical to a longitudinal direction of the through channels is (Y) cells/cm 2 , X and Y fall within a range surrounded by straight lines connecting points A 3 (X is 330, Y is 42.7), B 3 (X is 356, Y is 34.9), C 3 (X is 406, Y is 34.9), and D 3 (X is 381, Y is 42.7) in this order wherein the filter has a combination of X and Y that keeps a temperature gradient below 180Â° C./cm at a time of filter regeneration to prevent cracks from being generated.