# US 9,517,454 B2 · Diesel particulate filter

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- Number: US 9,517,454 B2
- Document ID: US9517454B2
- Status: Granted
- Kind: B2
- Application number: 15/161,384
- Filed: 2016-05-23
- Published: 2016-10-27
- Granted: 2016-12-13
- Earliest claimed: 2010-06-02
- Assignees: Johnson Matthey Public Limited Company
- Applicants: Neal Sutton; Martyn Vincent Twigg
- Inventors: Neal Sutton; Martyn Vincent Twigg
- Web page: https://patentgrep.com/patent/US9517454B2

## CPC

- B01J 29/44: Noble metals
- B01D 53/94: by catalytic processes
- B01D 53/9418: {for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas}
- B01D 53/944: {Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445)}
- B01J 23/42: Platinum
- B01J 23/44: Palladium
- B01J 29/40: of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
- B01J 29/7015: {CHA-type, e.g. Chabazite, LZ-218}
- B01J 29/763: {CHA-type, e.g. Chabazite, LZ-218}
- B01J 29/80: Mixtures of different zeolites
- B01J 35/19: {Catalysts containing parts with different compositions}
- B01J 35/31: Density
- B01J 35/657: {larger than 1000 nm}
- B01J 37/0054: {Drying of aerosols}
- B01J 37/038: {to form slurries or suspensions, e.g. a washcoat}
- F01N 3/0222: {the structure being monolithic, e.g. honeycombs}
- F01N 3/035: with catalytic reactors
- B01D 2255/1021: Platinum
- B01D 2255/1023: Palladium
- B01D 2255/504: ZSM 5 zeolites
- B01J 35/56: Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths
- F01N 2370/04: Zeolitic material
- Y02T 10/12: Improving ICE efficiencies
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- 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)
- 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)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A method of making a filter for filtering particulate matter from exhaust gas emitted from a lean-burn internal combustion engine, which filter comprising a porous substrate having inlet surfaces and outlet surfaces, wherein the inlet surfaces are separated from the outlet surfaces by a porous structure containing pores of a first mean pore size, wherein the inlet surfaces comprise a bridge network comprising interconnected particles of refractory material over the pores of the porous structure, which method comprising the step of contacting inlet surfaces of the filter substrate with an aerosol comprising refractory material in dry powder form. The invention also relates to a filter obtainable by such method.

## Claims

### Claim 1

A method for producing a filter comprising spraying a dry particulate aerosol onto an inlet surface of a porous filter for filtering particulate matter from a lean-burn exhaust gas, to form a filter cake having a density of 0.3 to 1.2 g/in3, wherein said aerosol comprises inorganic particles selected from the group consisting of silicate zeolite, aluminosilicate zeolite, metal-substituted aluminosilicate zeolite, non-zeolitic molecular sieve, and metal oxide, provided that said metal oxide particles have an average size of greater than 0.2 μm and less than 5 μm,
wherein the filter comprises: (a) a porous substrate having an inlet surface and an outlet surface, wherein the inlet surface and the outlet surface are separated by a porous structure; and (b) a catalytic filter cake in the form of a bridge network on the inlet surface, said bridge network comprising interconnected inorganic particles selected from the group consisting of silicate zeolite, aluminosilicate zeolite, metal-substituted aluminosilicate zeolite, non-zeolitic molecular sieve, and metal oxide, provided that said metal oxide particles have an average size of greater than 0.2 μm and less than 5 μm, where the interconnected inorganic particles are dry aerosol deposited, the particles form a bridge over the pores.

### Claim 2 (depends on 1)

The method of claim 1 wherein said inorganic particles of said aerosol are derived from a powder having a bulk density of 0.1 to 0.4 g/cm3.

### Claim 3 (depends on 1)

The method of claim 1 wherein said dry particulate aerosol is deposited on an untreated substrate.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the cake is derived from a powder having a bulk density of 0.05 to 1 g/cm3.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the porous substrate as a mean pore diameter of about 11-22 μm.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the porous substrate is a wall-flow filter.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the cake is present in an amount less than 1.2 g/in3.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the inorganic particles are a Selective Catalytic Reduction (SCR) catalyst.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the inorganic particles are selected from the group consisting of alumina, silica, zirconia, ceria, chromia, magnesia, calcia, titania and mixed oxides of any two or more thereof.

### Claim 10 (depends on 1)

The method of according claim 1, wherein the inorganic particles are zeolite or a non-zeolite molecular sieve having a CHA framework.

### Claim 11 (depends on 1)

The method according to claim 1 further comprising a catalytic washcoat selected from the group consisting of Three-Way-Catalyst (TWC), NOx absorber, oxidation catalyst, hydrocarbon trap, lean NOx catalyst, and combinations thereof.

### Claim 12 (depends on 1)

The method according to claim 1, wherein the inorganic particles do not substantially enter the pores of the porous substrate.