Ceramic honeycomb filter
A ceramic honeycomb filter comprising a honeycomb structure having a large number of flow paths partitioned by porous cell walls; and plugs formed in the flow paths alternately on the exhaust gas inlet and outlet sides; the thickness W (mm) and permeability κ (μm 2 ) of the cell wall and the length L (mm) and cross section area A (mm 2 ) perpendicular to the length direction of the flow path meeting the relations of 0.1≦W≦0.5, 8≦κ/W≦26.7, and 125≦L/A 0.5 ≦360.
1. A ceramic honeycomb filter comprising a honeycomb structure having a large number of flow paths partitioned by porous cell walls; and plugs formed in the flow paths alternately on the exhaust gas inlet and outlet sides; a bulk density of said ceramic honeycomb filter being less than 0.5 g/cm 3 ; the thickness W (mm) and permeability κ (μm 2 ) of the cell wall, the length L (mm) and cross section area A (mm 2 ) perpendicular to the length direction of the flow path, and the length L (mm) and the cross section area S (mm 2 ) perpendicular to the length direction of the honeycomb filter, the meeting the following relations:
0.1 ≦W≦ 0.5;
2≦κ≦8;
8 ≦κ/W≦ 26.7;
125 ≦L/A 0.5 ≦360;
0.75 ≦L/S 0.5 ; and
wherein a foam resin of a pore-forming material is added to a moldable material to adjust the permeability.
2. The ceramic honeycomb filter according to claim 1 , wherein the L and S satisfy the relation of 0.75≦L/S 0.5 ≦1.2.
3. The ceramic honeycomb filter according to claim 1 , wherein the length L is 140 mm or more.
4. The ceramic honeycomb filter according to claim 1 , wherein the distance between an outlet-side end of the inlet-side plug and an inlet-side end of the outlet-side plug is 120 mm or more.