Pillar-shaped honeycomb structure filter

Patent metadata

Field	Value
Publication number	US-11612844-B2
Application number	US-202217652310-A
Country	US
Kind code	B2
Filing date	Feb 24, 2022
Priority date	Mar 31, 2021
Publication date	Mar 28, 2023
Grant date	Mar 28, 2023

Abstract

A pillar-shaped honeycomb structure including a plurality of first cells extending from an inlet side end surface to an outlet side end surface, and a plurality of second cells extending from the inlet side end surface to the outlet side end surface, with a porous partition wall interposed therebetween, wherein a porous film having a porosity higher than that of the partition walls is provided on a surface of each of the first cells, and at a cross-section orthogonal to the direction in which the first cells of the pillar-shaped honeycomb structure filter extend, the average thickness of the porous film in the central portion is larger than the average thickness of the porous film in the outer peripheral portion.

First claim

The invention claimed is:

1. A pillar-shaped honeycomb structure filter comprising a plurality of first cells extending from an inlet side end surface to an outlet side end surface, each opening on the inlet side end surface and having a plugged portion on the outlet side end surface, and a plurality of second cells extending from the inlet side end surface to the outlet side end surface, each having a plugged portion on the inlet side end surface and opening on the outlet side end surface, the plurality of first cells and the plurality of second cells alternately arranged adjacent to each other with a porous partition wall interposed therebetween,
wherein a porous film having a porosity higher than that of the partition wall is provided on a surface of each of the first cells, and
assuming that a direction in which the first cells of the pillar-shaped honeycomb structure filter extend is an extending direction of a coordinate axis, a coordinate value of the inlet side end surface is 0, and a coordinate value of the outlet side end surface is X, the following relationship is satisfied:
( A 1 +A 2 +A 3 )/( B 1 +B 2 +B 3 )>1.0

wherein
B 1 is an average thickness of the porous film in an outer peripheral portion, and A 1 is an average thickness of the porous film in a central portion, at a cross-section orthogonal to the direction in which the first cells of the pillar-shaped honeycomb structure filter extend at a coordinate value of 0.2X,
B 2 is an average thickness of the porous film in the outer peripheral portion, and A 2 is an average thickness of the porous film in the central portion, at a cross-section orthogonal to the direction in which the first cells of the pillar-shaped honeycomb structure filter extend at a coordinate value 0.5X, and
B 3 is an average thickness of the porous film in the outer peripheral portion, and A 3 is an average thickness of the porous film in the central portion, at a cross-section orthogonal to the direction in which the first cells of the pillar-shaped honeycomb structure filter extend at a coordinate value 0.8X.

2. The pillar-shaped honeycomb structure filter according to claim 1 , wherein the following relationship is satisfied.
( A 1 +A 2 +A 3 )/( B 1 +B 2 +B 3 )≥1.2

3. The pillar-shaped honeycomb structure filter according to claim 1 , wherein the following relationships (1) and (2) are satisfied for the first cells located in the central portion of the cross-section orthogonal to the direction in which the first cells of the pillar-shaped honeycomb structure filter extend:
(1) a ratio (A 2 /A 1 ) of the average thickness A 2 of the porous film at the coordinate value 0.5X to the average thickness A 1 of the porous film at the coordinate value 0.2X is 1.05 to 5.0, and
(2) a ratio (A 3 /A 1 ) of the average thickness A 3 of the porous film at the coordinate value 0.8X to the average thickness A 1 of the porous film at the coordinate value 0.2X is 1.05 to 5.0.

4. The pillar-shaped honeycomb structure filter according to claim 1 , wherein the following relationship is satisfied.
A 1 >B 1 ,A 2 >B 2 , and A 3 >B 3

5. The pillar-shaped honeycomb structure filter according to claim 1 , wherein a main component of the porous film is silicon carbide, alumina, silica, cordierite or mullite.

6. The pillar-shaped honeycomb structure filter according to claim 1 , wherein the porosity of the porous film is 70 to 85%.

7. The pillar-shaped honeycomb structure filter according to claim 1 , wherein an average thickness of the entire porous film is 4 to 50 μm.

Assignees

• Ngk Insulators Ltd

Inventors

• Sato Yoshihiro
• Ueda Shuji
• Sendo Koichi
• Ishii Yutaka
• Tajima Yuichi
• Nakano Seiya
• Itazu Ken

Classifications

• B01D46/2429

  of the honeycomb walls or cells · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title

• B01D46/2474 Primary

  of the walls along the length of the honeycomb · CPC title

• B01D46/24491 Primary

  Porosity · CPC title

• F01N3/0222 Primary

  the structure being monolithic, e.g. honeycombs · CPC title