Patent ID: 9702283
Date: 2017-07-11
CPC Classifications: B01D,C04B,F01N

Claim:
1. A honeycomb filter comprising: a silicon carbide honeycomb fired body comprising a plurality of cells through which exhaust gas is to flow and which include exhaust gas introduction cells and exhaust gas emission cells, the exhaust gas introduction cells each having an open end at an exhaust gas introduction side and a plugged end at an exhaust gas emission side, the exhaust gas emission cells each having an open end at the exhaust gas emission side and a plugged end at the exhaust gas introduction side, the silicon carbide honeycomb fired body including silicon carbide grains having a silicon-containing oxide layer with a thickness of 0.1 to 2 μm on surfaces of the silicon carbide grains, the exhaust gas introduction cells and the exhaust gas emission cells each having a uniform cross sectional shape except for a plugged portion in a cross section perpendicular to a longitudinal direction of the plurality of cells thoroughly from the exhaust gas introduction side to the exhaust gas emission side; an end face with an aperture ratio of not less than 20% at the exhaust gas emission side; and porous cell walls defining rims of the plurality of cells, the plugged portions of the exhaust gas introduction cells being arranged in vertical and horizontal lines with the porous cell walls residing between the plugged portions in the end face at the exhaust gas emission side, wherein each of the exhaust gas emission cells is adjacently surrounded fully by the exhaust gas introduction cells across the porous cell walls, wherein the exhaust gas introduction cells include first exhaust gas introduction cells and second exhaust gas introduction cells, wherein each of the second exhaust gas introduction cells has a cross sectional area larger than a cross sectional area of each of the first exhaust gas introduction cells in the cross section perpendicular to the longitudinal direction of the plurality of cells, wherein each of the exhaust gas emission cells has a cross sectional area equal to or larger than the cross sectional area of each of the second exhaust gas introduction cells in the cross section perpendicular to the longitudinal direction of the plurality of cells, wherein, in the cross section perpendicular to the longitudinal direction of the plurality of cells, the exhaust gas introduction cells and the exhaust gas emission cells each have a polygonal shape, and wherein, in the cross section perpendicular to the longitudinal direction of the plurality of cells,