# US 10,870,077 B2 · Porous honeycomb filter

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- Number: US 10,870,077 B2
- Document ID: US10870077B2
- Status: Granted
- Kind: B2
- Application number: 16/452,937
- Filed: 2019-06-26
- Published: 2019-10-17
- Granted: 2020-12-22
- Earliest claimed: 2016-12-27
- Assignees: Denso Corporation
- Applicants: Denso Corporation
- Inventors: Yasushi Takayama; Shusaku Yamamura
- Web page: https://patentgrep.com/patent/US10870077B2

## CPC

- B01D 46/2429: {of the honeycomb walls or cells}
- B01D 39/2075: {sintered or bonded by inorganic agents}
- 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 46/24491: {Porosity}
- B01D 46/247: {of the cells}
- B01D 46/2474: {of the walls along the length of the honeycomb}
- B01D 46/2482: {Thickness, height, width, length or diameter}
- B01D 46/2484: {Cell density, area or aspect ratio}
- C04B 35/195: Alkaline earth aluminosilicates, e.g. cordierite {or anorthite}
- C04B 38/0009: {characterised by features relating to the cell walls, e.g. wall thickness or distribution of pores in the walls}
- C04B 38/0016: {assembled from subunits}
- B01D 2239/1208: Porosity
- B01D 2279/30: for treatment of exhaust gases from IC Engines
- C04B 2111/00793: {as filters or diaphragms}
- C04B 2111/0081: {as catalysts or catalyst carriers}
- C04B 2235/3436: Alkaline earth metal silicates, e.g. barium silicate
- 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)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE

## Abstract

Provided is a porous honeycomb filter comprising a porous first cell wall that permits exhaust gas to permeate, a second cell wall that permits exhaust gas to permeate than the first cell wall, and a cell that is surrounded by the first cell wall and the second cell wall to form an extending gas flow passage. The second cell wall has a smaller porosity than the first cell wall.

## Claims

### Claim 1

A porous honeycomb filter comprising:
a porous first cell wall that permits exhaust gas to permeate;
a second cell wall that permits the exhaust gas to permeate less easily than the first cell wall; and
a cell that is surrounded by the first cell wall and the second cell wall to form an extending gas flow passage, wherein
the second cell wall has a smaller porosity than the first cell wall,
the cell comprises a plurality of cells,
the porous honeycomb filter further comprising a tubular outer shell constituting an outer periphery thereof,
a plurality of the first cell walls and a plurality of the second cell walls partition an inside of the tubular outer shell into the cells,
the first cell walls include an inclined wall extending inclined relative to an axial direction of the tubular outer shell, and the second cell walls include a parallel wall extending parallel to the axial direction.

### Claim 2 (depends on 1)

The porous honeycomb filter according to claim 1, wherein,
in a cross section of the porous honeycomb filter in the direction orthogonal to the axial direction, a cross-sectional area Sa occupied by a plurality of the first cell walls and a cross-sectional area Sb occupied by a plurality of the second cell walls satisfy the following condition:
Sa>Sb.

### Claim 3 (depends on 2)

The porous honeycomb filter according to claim 2, wherein
the number of the second cell walls is fewer than the number of the first cell walls.

### Claim 4 (depends on 2)

The porous honeycomb filter according to claim 2, wherein
a thickness T1 of each first cell wall and a thickness T2 of each second cell wall satisfy the following condition:
T1<T2.

### Claim 5 (depends on 1)

The porous honeycomb filter according to claim 1, wherein
the first cell walls include a pair of the inclined walls that face each other, and an inclination direction of one of the inclined walls of the pair is symmetrical to an inclination direction of the other of the inclined walls of the pair with respect to the axial direction.

### Claim 6 (depends on 5)

The porous honeycomb filter according to claim 5, wherein:
the porous honeycomb filter has an inflow end surface into which the exhaust gas flows and an outflow end surface out of which the exhaust gas flows, the inflow end surface and the outflow end surface being respectively arranged at opposite ends of the axial direction;
the cells include:
a reduction cell having a gas flow passage cross-sectional area that decreases from the inflow end surface toward the outflow end surface, and
an enlargement cell having a gas flow passage cross-sectional area that increases from the inflow end surface toward the outflow end surface of the cell; and
the reduction cell and the enlargement cell are arranged adjacent to each other to share one of the inclined walls.

### Claim 7 (depends on 6)

The porous honeycomb filter according to claim 6, wherein
the reduction cell comprises reduction cells that are adjacent to each other via one of the parallel walls, and the enlargement cell comprises enlargement cells that are adjacent to each other via one of the parallel walls.

### Claim 8 (depends on 6)

The porous honeycomb filter according to claim 6, further comprising
an outflow-side connecting part that connects the pair of inclined walls constituting the reduction cell directly or via a connecting member; and
an inflow-side connecting part connects the pair of inclined walls constituting the enlargement cell directly or via the connecting member.

### Claim 9 (depends on 8)

The porous honeycomb filter according to claim 8, wherein
the connecting member is comprised of a constituent member identical to the inclined wall.

### Claim 10 (depends on 8)

The porous honeycomb filter according to claim 8, wherein:
the outflow-side connecting part is formed on the outflow end surface in the axial direction; and
the inflow-side connecting part is formed on the outflow end surface in the axial direction.

### Claim 11 (depends on 8)

The porous honeycomb filter according to claim 8, wherein:
the outflow-side connecting part is disposed to be more inner in the axial direction than the outflow end surface; and
the inflow-side connecting part is disposed to be more inner in the axial direction than the inflow end surface.

### Claim 12 (depends on 8)

The porous honeycomb filter according to claim 8, wherein
the inclined wall is inclined linearly between the inflow-side connecting part and outflow-side connecting part.

### Claim 13 (depends on 8)

The porous honeycomb filter according to claim 8, wherein:
the inclined wall extending in the axial direction has an inflow-side curvilinearly inclined area that is curvilinearly inclined toward the inflow end surface side and an outflow-side curvilinearly inclined area that is curvilinearly inclined toward the outflow end surface side;
in the reduction cell, the pair of inclined walls are connected to each other in the outflow-side curvilinearly inclined area to form the outflow-side connecting part; and
in the enlargement cell, the pair of inclined walls are connected to each other in the inflow-side curvilinearly inclined area to form the inflow-side connecting part.

### Claim 14 (depends on 13)

The porous honeycomb filter according to claim 13, wherein,
in each of the outflow-side connecting part and the inflow-side connecting part, an inclination direction of one of the inclined walls of the pair is symmetrical to the inclination direction of the other of the inclined walls of the pair with respect to the axial direction.

### Claim 15 (depends on 6)

The porous honeycomb filter according to claim 6, wherein
each of the second cell walls has an axial end part, and the axial end part is disposed to be more inner in the axial direction than the inflow end surface and the outflow end surface of the porous honeycomb filter.

### Claim 16 (depends on 1)

The porous honeycomb filter according to claim 1, wherein
the cells include adjacent cells adjacent to each other via one of the first cell walls,
each of the adjacent cells via one of the first cell walls has a gas flow passage cross-sectional area at any arbitrary position in an axial direction of the tubular outer shell, and
the gas flow passage cross-sectional area of one of the adjacent cells via one of the first cell walls is different from the gas flow passage cross-sectional area of the other of the adjacent cells.

### Claim 17 (depends on 1)

The porous honeycomb filter according to claim 1, wherein
the cells include adjacent cells adjacent to each other via one of the second cell walls,
each of the adjacent cells via one of the second cell walls has a gas flow passage cross-sectional area at any arbitrary position in an axial direction of the tubular outer shell, and
the gas flow passage cross-sectional area of one of the adjacent cells via one of the second cell walls is identical to the gas flow passage cross-sectional area of the other of the adjacent cells.

### Claim 18 (depends on 1)

The porous honeycomb filter according to claim 1, wherein
the second cell wall is made of a material that is stronger per unit thickness than a material of the first cell wall.

### Claim 19 (depends on 1)

The porous honeycomb filter according to claim 1, wherein
the first cell wall and the second cell wall are each made of a ceramic material whose main component is cordierite crystalline phase.

### Claim 20 (depends on 1)

The porous honeycomb filter according to claims 1, further comprising:
an exhaust gas purification catalyst supported by the first cell wall and second cell wall, wherein:
the exhaust gas purification catalyst is supported inside the first cell wall; and
the exhaust gas purification catalyst is supported on a surface of the second cell wall, the surface facing the gas flow passage.

### Claim 21

A porous honeycomb filter comprising:
a porous first cell wall that permits exhaust gas to permeate;
a second cell wall that permits the exhaust gas to permeate less easily than the first cell wall; and
a cell that is surrounded by the first cell wall and the second cell wall to form an extending gas flow passage, wherein
the second cell wall has a smaller porosity than the first cell wall,
the cell comprises a plurality of cells,
the porous honeycomb filter further comprising a tubular outer shell constituting an outer periphery thereof,
a plurality of the first cell walls and a plurality of the second cell walls partition an inside of the tubular outer shell into the cells,
in a cross section of the porous honeycomb filter in the direction orthogonal to the axial direction of the tubular outer shell, a cross-sectional area Sa occupied by a plurality of the first cell walls and a cross-sectional area Sb occupied by a plurality of the second cell walls satisfy the following condition:
Sa>Sb,
the number of the second cell walls is fewer than the number of the first cell walls.

### Claim 22 (depends on 21)

The porous honeycomb filter according to claim 21, wherein
a thickness T1 of each first cell wall and a thickness T2 of each second cell wall satisfy the following condition:
T1<T2.

### Claim 23

A porous honeycomb filter comprising:
a porous first cell wall that permits exhaust gas to permeate;
a second cell wall that permits the exhaust gas to permeate less easily than the first cell wall; and
a cell that is surrounded by the first cell wall and the second cell wall to form an extending gas flow passage, wherein
the second cell wall has a smaller porosity than the first cell wall,
the cell comprises a plurality of cells,
the porous honeycomb filter further comprising a tubular outer shell constituting an outer periphery thereof,
a plurality of the first cell walls and a plurality of the second cell walls partition an inside of the tubular outer shell into the cells,
in a cross section of the porous honeycomb filter in the direction orthogonal to the axial direction of the tubular outer shell, a cross-sectional area Sa occupied by a plurality of the first cell walls and a cross-sectional area Sb occupied by a plurality of the second cell walls satisfy the following condition:
Sa>Sb,
a thickness T1 of each first cell wall and a thickness T2 of each second cell wall satisfy the following condition:
T1<T2.