US6294141B1
Expired / Lapsed
US
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Emission control
Assignee: Johnson Matthey PLC
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Filing: 1997-10-14
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Granted: 2001-09-25
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Expires: 2017-10-14
Abstract
Abstract An emission control system especially for light duty diesel engines has a first catalyst, 2, positioned upstream of a second catalyst, 3. The first catalyst converts NO to NO2 and the second catalyst oxidises HC, CO and VOF. The tendency of the second catalyst to collect soot particles is reduced by combustion of the soot particles by NO2 from the first catalyst.
Inventors
- 👤 Martyn Vincent Twigg
- 👤 Anthony John Joseph Wilkins
- 👤 Nigel Simon Will
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:05
CPC Classifications
F; F01; F01N; F01N3/00; F01N3/08; F01N3/10; F01N3/24; F01N3/28; B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9459; B01D53/9463; B01D53/9472; F01N13/00; F01N13/009; F01N13/0097; F01N3/02; F01N3/021; F01N3/023; F01N3/0231; F01N3/033; F01N3/035; B01D2255/00; B01D2255/10; B01D2255/102; B01D2255/1021; B01D2258/00; B01D2258/01; B01D2258/012; B01D53/944; B01D53/9445; F01N2570/00; F01N2570/10; F01N2570/12; F01N2570/14; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24149
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
101 words
An emission control system for internal combustion engines which emit carbonaceous soot particles, which system comprising a first catalyst effective to oxidize NOx to NO 2 and a second catalyst effective to oxidize hydrocarbons, carbon monoxide and volatile organic fractions, each catalyst being supported on a honeycomb flow-through monolith, whereby soot particles trapped on or within said second catalyst are combusted in the NO 2 containing gas from said first catalyst, and wherein the first catalyst is supported on a flexible metal monolith of up to 31 cells/cm 2 , whereby soot particle collection on the first catalyst support is minimized.
Claim 2
Dependent Claim
101 words
An emission control system for internal combustion engines which emit carbonaceous soot particles, which system comprising a first catalyst effective to oxidize NOx to NO 2 and a second catalyst effective to oxidize hydrocarbons, carbon monoxide and volatile organic fractions, each catalyst being supported on a honeycomb flow-through monolith, whereby soot particles trapped on or within said second catalyst are combusted in the NO 2 containing gas from said first catalyst, and wherein the first catalyst is supported on a flexible metal monolith of up to 31 cells/cm 2 , whereby soot particle collection on the first catalyst support is minimized.
Claim 3
Dependent Claim
21 words
A system according to claim 1 , wherein said first catalyst contains 1.77 to 7.06 g/liter of catalyst volume, of platinum.
Claim 4
Dependent Claim
20 words
A system according to claim 1 , wherein said second catalyst is selected from oxidation catalysts and lean-NOx three-way catalysts.
Claim 5
Dependent Claim
28 words
An internal combustion engine which emits carbonaceous soot particles during at least part of the operating cycle, fitted with an emission control system according to claim 1 .
Claim 6
Dependent Claim
15 words
A light-duty diesel engine, fitted with an emission control system according to claim 1 .
Claim 7
Dependent Claim
94 words
In a process for the purification of exhaust gases from a light duty internal combustion engine which emits carbonaceous soot particles by passing said gases over a honeycomb flow-through monolith and an oxidation catalyst effective at least to oxidize HC, CO and VOF, the improvement comprising first passing said gases over a first catalyst effective to oxidize NOx to NO 2 and subsequently passing the gas enriched with NO 2 over said honeycomb flow-through monolith and oxidation catalyst in order to enhance catalytic oxidation of soot particles trapped on or within said oxidation catalyst.
Claim 8
Dependent Claim
94 words
In a process for the purification of exhaust gases from a light duty internal combustion engine which emits carbonaceous soot particles by passing said gases over a honeycomb flow-through monolith and an oxidation catalyst effective at least to oxidize HC, CO and VOF, the improvement comprising first passing said gases over a first catalyst effective to oxidize NOx to NO 2 and subsequently passing the gas enriched with NO 2 over said honeycomb flow-through monolith and oxidation catalyst in order to enhance catalytic oxidation of soot particles trapped on or within said oxidation catalyst.
Claim 9
Dependent Claim
15 words
The process of claim 6 wherein the gas containing NO 2 also includes water vapor.
Claim 10
Dependent Claim
15 words
The process of claim 6 , wherein the oxidation catalyst comprises a platinum group metal.
Claim 11
Dependent Claim
19 words
The process of claim 8 , wherein the oxidation catalyst comprises a platinum group metal on a monolithic honeycomb.
Claim 12
Dependent Claim
20 words
The process of claim 9 , wherein the honeycomb flow through catalyst includes a catalyst which facilitates particulate catalytic oxidation.
Claim 13
Dependent Claim
15 words
The process of claim 10 , wherein the oxidation catalyst is a three way catalyst.
Claim 14
Dependent Claim
110 words
An emission control system for an internal combustion engine which emits carbonaceous soot particles, which system comprising a first catalyst effective to oxidize NOx to NO 2 and a second catalyst effective to oxidize hydrocarbons, carbon monoxide and volatile organic fractions, each catalyst being supported on a honeycomb flow-through monolith, the cell density and dimensions of said respective monoliths being selected to provide a greater space velocity over said first catalyst than over said second catalyst whereby soot particle collection on the first catalyst support is minimized and whereby soot particles trapped on or within said second catalyst are combusted in the NO 2 containing gas from said first catalyst.
Claim 15
Dependent Claim
110 words
An emission control system for an internal combustion engine which emits carbonaceous soot particles, which system comprising a first catalyst effective to oxidize NOx to NO 2 and a second catalyst effective to oxidize hydrocarbons, carbon monoxide and volatile organic fractions, each catalyst being supported on a honeycomb flow-through monolith, the cell density and dimensions of said respective monoliths being selected to provide a greater space velocity over said first catalyst than over said second catalyst whereby soot particle collection on the first catalyst support is minimized and whereby soot particles trapped on or within said second catalyst are combusted in the NO 2 containing gas from said first catalyst.
Claim 16
Dependent Claim
21 words
A system according to claim 12 , wherein said first catalyst contains 1.77 to 7.06 g/liter of catalyst volume, of platinum.
Claim 17
Dependent Claim
20 words
A system according to claim 12 , wherein said second catalyst is selected from oxidation catalysts and lean-NOx three-way catalysts.
Claim 18
Dependent Claim
28 words
An internal combustion engine which emits carbonaceous soot particles during at least part of the operating cycle, fitted with an emission control system according to claim 12 .
Claim 19
Dependent Claim
15 words
A light-duty diesel engine, fitted with an emission control system according to claim 12 .
Claim 20
Dependent Claim
17 words
A system according to claim 12 , wherein said first catalyst support is a flexible metal monolith.
Claim 21
Dependent Claim
24 words
A system in accordance with claim 17 , wherein the cell density of said first monolith is up to 200 cells per square inch.
Claim 22
Dependent Claim
20 words
A system in accordance with claim 18 , wherein the cell density of at least 400 cells per square inch.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-09-24 | 2005-03-26 | 2005-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-09-24 | 2009-03-26 | 2009-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-09-24 | 2013-03-26 | 2013-09-25 | $7700.00 | Window Closed / Lapsed |