| abstract |
A honeycomb filter (20) comprises a plurality of porous wall portions (22) that form a plurality of cells (23), each of which has an open end and a sealed end, serving as flow channels of exhaust gas; and collecting layers (24) formed on the wall portions (22) to collect and remove solid constituents contained in the exhaust gas. The cells include surplus-deposit carrying cells (25) that carry more solid constituents than other cells, and a percentage R of the number of the surplus-deposit carrying cells to the number of all cells is 0 < R ≤ 20%. Since the channel resistance of the surplus-deposit carrying cells (25) is low, the flow rate of fluid is increased, and more solid constituents are apt to deposit on the surplus-deposit carrying cells. During recovery process in which the solid constituents are burned, the quantity of heat, associated with the recovery efficiency, generated in accordance with the amount of collected solid constituents is apt to increase, and the combustion of the solid constituents at the surplus-deposit carrying cells (25) acts as an ignition point. |