Exhaust gas purifying filter

Patent metadata

Field	Value
Publication number	US-11767779-B2
Application number	US-202117451823-A
Country	US
Kind code	B2
Filing date	Oct 22, 2021
Priority date	Apr 26, 2019
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

Provided is an exhaust gas purifying filter used with a HC purifying catalyst supported thereon. Numerous pores are formed in partitions of the exhaust gas purifying filter. In a cross-section of the partition, pores are open at a passage surface, having an open end of which the opening diameter is 50 μm or larger. In the cross-section of the partitions, the partitions include a narrow part where a pore diameter is 5 μm or more and the pore diameter becomes a minimum in a region. In the cross-section of the partitions, the region is positioned between a pair of virtual lines L 1 and L 2 extending from opposing sides of the opening end to a passage surface positioned opposite to the opening end along the wall thickness direction X, Z. The pore diameter at the narrow part is 6% or more and less than or equal to 20% of the opening diameter.

First claim

What is claimed is:

1. An exhaust gas purifying filter used with a HC purifying catalyst carried thereon, comprising:
a honeycomb structure part having a partition including numerous pores formed therein, and a plurality of cells divided by the partition, forming a passage for an exhaust gas; and
an opening sealed portion that alternately seals an inflow end surface or an outflow end surface of the exhaust gas in the cells,
wherein
in a cross-section of the partition sectioned along a wall thickness direction, each pore is open at a passage surface facing the cells, having an opening end of which the opening diameter is 50 μm or larger;
the partition includes a narrow part in a region positioned between a pair of virtual lines extending from opposing sides of the opening end to a passage surface positioned opposite to the opening end along the wall thickness direction, the narrow part having a pore diameter of 5 μm or more and the pore diameter being a minimum in the region; and
the pore diameter at the narrow part is 6% or more and less than or equal to 20% of the opening diameter.

2. The exhaust gas purifying filter according to claim 1 , wherein
the partition is formed such that a pore volume ratio of pores having a pore diameter of less than or equal to 11 μm is 3% or more where pore diameter is measured based on the mercury penetration method.

3. The exhaust gas purifying filter according to claim 2 , wherein
the pore volume ratio is less than or equal to 20%.

4. The exhaust gas purifying filter according to claim 1 , further comprising a catalyst layer containing the HC purifying catalyst which is supported by the partition,
wherein
a supported amount of the catalyst layer is from 30 g/L to 80 g/L; and
in a cross-section of the partition sectioned along a wall thickness direction, the catalyst layer formed around the narrow part has a thickness difference between portions in opposing sides od the narrow part.

5. The exhaust gas purifying filter according to claim 4 , wherein
a larger side thickness T 1 and a smaller side thickness T 2 in a thickness of the catalyst layer across the narrow part satisfy a relationship T 2 /T 1 ≤0.6.

6. The exhaust gas purifying filter according to claim 1 , wherein:
the passage facing the cells has the opening end defined therein and is a first passage surface;
the passage surface positioned opposite to the opening end along the wall thickness direction is a second passage surface; and
the narrow part is position between the first passage surface and the second passage surface along the wall thickness direction.

Assignees

• Denso Corp

Inventors

• Kayama Hiroaki
• Koike Kazuhiko

Classifications

• B01J35/57

  Honeycombs · CPC title

• F01N3/10 Primary

  by thermal or catalytic conversion of noxious components of exhaust · CPC title

• B01J35/04

  Operations & Transport · mapped topic

• B01J35/1033

  Operations & Transport · mapped topic

• B01J35/1076

  Operations & Transport · mapped topic