Method of manufacturing plugged honeycomb structure, and plugged honeycomb structure

A method of manufacturing a plugged honeycomb structure,

• the plugged honeycomb structure comprising:
• a cylindrical honeycomb structure having a first end, a second end that is opposite to the first end, porous partition walls and a plurality of cells partitioned by the partition walls, the partition walls and the cells extending through the cylindrical honeycomb structure from the first end to the second end, and
• plugging members which plug portions of predetermined sells in such a way that the predetermined cells are plugged only at the first end and not plunged at the second end, the remaining cells are not plugged at any position between the first and the second end, the plugging members having a predetermined length from file first end of each of the predetermined cells,
• wherein the plugged honeycomb structure is in a casing inside an exhaust structure,
• the method comprising the steps of:
• forming a clay including a forming material into a honeycomb shape to obtain a cylindrical honeycomb formed body having a plurality of partitioned cells extending through the formed body from the first end to the second end;
• firing the resultant honeycomb formed body to obtain the honeycomb structure;
• preparing a plugging material of the plugging members so that a contraction ratio (firing contraction ratio) of the plugging material during firing is a predetermined ratio with respect to the firing contraction ratio of the honeycomb structure;
• plugging openings of the predetermined cells of the resultant honeycomb structure only at the first end with the plugging material to obtain a plugged honeycomb precursor;
• and
• firing the resultant plugged honeycomb precursor in a state in which the plugged honeycomb precursor is laid on a firing setter so as to bring the first end plugged with the plugging material into contact with the firing setter to thereby obtain the plugged honeycomb structure.

A plugged honeycomb structure comprising:

• a cylindrical honeycomb structure having a first end, a second end that is opposite to the first end, porous partition walls and a plurality of partitioned cells, the partition walls and the cells extending through the cylindrical honeycomb structure from the first end to the second end;
• and
• plugging members which plug portions of predetermined cells in such a way that the predetermined cells are plugged only at the first end and not plugged at the second end, the remaining cells are not plugged at any position between the first and the second end, the plugging members having a predetermined length from the first end of each of the predetermined cells,
• wherein the plunged honeycomb structure is in a casing inside an exhaust structure,
• the plugged honeycomb structure being constituted so that a ratio (length/outer diameter) of a length of the honeycomb structure in an axial direction with respect to the outer diameter of the cylindrical honeycomb structure is in a range of 0.1 to 0.8.