# US 10,883,401 B2 · Exhaust gas purification filter

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- Number: US 10,883,401 B2
- Document ID: US10883401B2
- Status: Granted
- Kind: B2
- Application number: 16/711,700
- Filed: 2019-12-12
- Published: 2020-04-16
- Granted: 2021-01-05
- Earliest claimed: 2017-06-13
- Assignees: Denso Corporation
- Applicants: Denso Corporation
- Inventors: Mikio Ishihara
- Web page: https://patentgrep.com/patent/US10883401B2

## CPC

- F01N 3/0222: {the structure being monolithic, e.g. honeycombs}
- B01D 39/20: of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires (porous ceramic material {C04B38/00} ; sintering metals C22C1/04; {making porous sintered metal bodies B22F3/10, honeycomb filters B01D46/2418, materials used for filtering exhaust gases of an internal combustion engine F01N3/022, ceramic honeycomb structures C04B38/0006})
- B01D 46/00: Filters or filtering processes specially modified for separating dispersed particles from gases or vapours (filtering elements B01D24/00-B01D35/00; filtering material B01D39/00; their regeneration outside the filters B01D41/00)
- B01D 53/94: by catalytic processes
- B01J 35/56: Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths
- F01N 3/2803: {characterised by structure, by material or by manufacturing of catalyst support}
- F01N 2330/06: Ceramic, e.g. monoliths
- F01N 2330/48: characterised by the number of flow passages, e.g. cell density
- F01N 2330/60: Discontinuous, uneven properties of filter material, e.g. different material thickness along the longitudinal direction; Higher filter capacity upstream than downstream in same housing
- Y02T 10/12: Improving ICE efficiencies
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An exhaust gas purification filter comprises: a casing; a porous dividing wall which partitions the inside of the casing into a honeycomb shape; and cells enclosed by the dividing wall. A pore path length distribution of the dividing wall, when expressed by a frequency histogram per 10 μm of the pore path length of the dividing wall, has an integrated frequency of at least 58%. The integrated frequency is a maximum value of a value obtained by summing the frequencies of a total of three adjacent levels which include the maximum peak frequency. The dividing wall preferably has a gas permeability coefficient k of at least 0.8×10−12 m2.

## Claims

### Claim 1

An exhaust gas purification filter comprising:
a casing;
a porous dividing wall which partitions the inside of the casing into a honeycomb shape;
and cells enclosed by the dividing wall; wherein
a pore path length distribution of the dividing wall, when expressed by a frequency histogram per 10 μm of the pore path length of the dividing wall, has an integrated frequency of at least 58%, the integrated frequency being a maximum value of a value obtained by summing the frequencies of a total of three adjacent levels which include the maximum peak frequency.

### Claim 2 (depends on 1)

The exhaust gas purification filter according to claim 1, wherein
a gas permeability coefficient k of the dividing wall is at least 0.8×10−12 m2.

### Claim 3 (depends on 2)

The exhaust gas purification filter according to claim 2, wherein
a particulate matter collection rate A and the gas permeability coefficient k of the exhaust gas purification filter satisfy the relationship in equation (I) below:
A>−3.94k2−32.67k+91.45 (I).