US5943857A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diesel engine exhaust gas purification method
Assignee: Johnson Matthey PLC
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Filing: 1996-06-05
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Granted: 1999-08-31
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Expires: 2016-06-05
Abstract
Abstract A process for the improved conversion of NO x in the exhaust gases from a light diesel engine using lean NO x catalyst converter in the exhaust system. The process is characterized in that unburned hydrocarbons are adsorbed into an adsorbent in the catalytic converter at temperatures below 190° C. during cooler parts of the operating cycle, and are desorbed in the temperature range of 198° to 200° C. during hotter parts of the operating cycle. The desorbed hydrocarbons are combined with unburned hydrocarbons in the exhaust to form a composition stream having a higher amount of hydrocarbons than either constituent stream which are then oxidized at the same time as at least a portion of the NO x is catalytically reduced to form N 2 .
Inventors
- 👤 Graham Paul Ansell
- 👤 Janet Mary Fisher
- 👤 Peter Geoffrey Gray
- 👤 Hugh Gavin Charles Hamilton
- 👤 Raj Rao Rajaram
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:45
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9413; B01D53/9418; B01D53/9481; B01D53/9486; F; F01; F01N; F01N3/00; F01N3/08; F01N3/0807; F01N3/0814; F01N3/0828; F01N3/0835; F01N3/0871; F01N3/10; F01N3/18; F01N3/20; B01D2255/00; B01D2255/10; B01D2255/102; B01D2255/1021; B01D2255/20; B01D2255/207; B01D2255/20761; B01D2255/50; B01D2255/504; F01N2610/00; F01N2610/03; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
124 words
A process for the improved conversion of NO x in the exhaust gases from a light-duty diesel engine using a lean NO x catalyst convertor in the exhaust system, characterized in that unburned hydrocarbons are: adsorbed into an adsorbent in the catalytic convertor at temperatures below 190° C. during cooler parts of the operating cycle, are desorbed in the temperature range of 190° C. to 250° C. during hotter parts of the operating cycle, and by said desorption are thus combined with unburned hydrocarbons in the exhaust to form a combined exhaust stream which is at or below 250° C. in which at least a portion of the NO x is catalytically reduced to N 2 while said combined exhaust stream is simultaneously oxidized.
Claim 2
Dependent Claim
124 words
A process for the improved conversion of NO x in the exhaust gases from a light-duty diesel engine using a lean NO x catalyst convertor in the exhaust system, characterized in that unburned hydrocarbons are: adsorbed into an adsorbent in the catalytic convertor at temperatures below 190° C. during cooler parts of the operating cycle, are desorbed in the temperature range of 190° C. to 250° C. during hotter parts of the operating cycle, and by said desorption are thus combined with unburned hydrocarbons in the exhaust to form a combined exhaust stream which is at or below 250° C. in which at least a portion of the NO x is catalytically reduced to N 2 while said combined exhaust stream is simultaneously oxidized.
Claim 3
Dependent Claim
15 words
A process as claimed in claim 1, wherein the adsorbent is admixed with the catalyst.
Claim 4
Dependent Claim
19 words
A process as claimed in claim 1, wherein the adsorbent is admixed with a washcoat carried on a monolith.
Claim 5
Independent Claim
134 words
A method for the improvement of aggregate NO x conversion in the exhaust gases from a light-duty diesel engine, said exhaust gases comprising CO, unburned hydrocarbons, and NO x wherein the temperature of said exhaust gases cycles below and above 190° C. a multiplicity of times during every engine operation, said method comprising: adsorbing unburned hydrocarbons when said gas temperature is below 190° C.; permitting adsorbed hydrocarbons to desorb when said gas temperature is in the range 190° to 250° C. such that said desorbed hydrocarbons combine with unburned hydrocarbons in the exhaust gases to form a combined exhaust stream, said combined exhaust stream at or below 250° C.; and catalytically reducing at least a portion of the NO x in the gases flowing from the engine while simultaneously oxidizing said combined exhaust stream.
Claim 6
Independent Claim
134 words
A method for the improvement of aggregate NO x conversion in the exhaust gases from a light-duty diesel engine, said exhaust gases comprising CO, unburned hydrocarbons, and NO x wherein the temperature of said exhaust gases cycles below and above 190° C. a multiplicity of times during every engine operation, said method comprising: adsorbing unburned hydrocarbons when said gas temperature is below 190° C.; permitting adsorbed hydrocarbons to desorb when said gas temperature is in the range 190° to 250° C. such that said desorbed hydrocarbons combine with unburned hydrocarbons in the exhaust gases to form a combined exhaust stream, said combined exhaust stream at or below 250° C.; and catalytically reducing at least a portion of the NO x in the gases flowing from the engine while simultaneously oxidizing said combined exhaust stream.
Claim 7
Independent Claim
179 words
A method for the improvement of aggregate NO x conversion in the exhaust gases from a light-duty diesel engine, said exhaust gases comprising CO, unburned hydrocarbons, and NO x wherein the temperature of said exhaust gases cycles, a multiplicity of times during every engine operation, from a cooler temperature to a hotter temperature, relative to an average exhaust gas temperature, wherein said hotter temperature includes the range from 190° C. to 250° C., and said exhaust gases are contacted with an NO x reducing catalyst which reversibly adsorbs unburned hydrocarbons and desorbs said hydrocarbons at a temperature in the range of 190° C.-250° C., said method comprising contacting said exhaust gases with said catalyst continuously throughout said cycles, said catalyst converter: adsorbing unburned hydrocarbons when said gas temperature is below 190° C.; desorbing said unburned hydrocarbons into said exhaust stream when said exhaust gas temperature is in the range 190° to 250° C., and simultaneously catalytically reducing at least a portion of the NO x in the gases flowing from the engine while simultaneously oxidizing said combined exhaust stream.
Claim 8
Independent Claim
179 words
A method for the improvement of aggregate NO x conversion in the exhaust gases from a light-duty diesel engine, said exhaust gases comprising CO, unburned hydrocarbons, and NO x wherein the temperature of said exhaust gases cycles, a multiplicity of times during every engine operation, from a cooler temperature to a hotter temperature, relative to an average exhaust gas temperature, wherein said hotter temperature includes the range from 190° C. to 250° C., and said exhaust gases are contacted with an NO x reducing catalyst which reversibly adsorbs unburned hydrocarbons and desorbs said hydrocarbons at a temperature in the range of 190° C.-250° C., said method comprising contacting said exhaust gases with said catalyst continuously throughout said cycles, said catalyst converter: adsorbing unburned hydrocarbons when said gas temperature is below 190° C.; desorbing said unburned hydrocarbons into said exhaust stream when said exhaust gas temperature is in the range 190° to 250° C., and simultaneously catalytically reducing at least a portion of the NO x in the gases flowing from the engine while simultaneously oxidizing said combined exhaust stream.
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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) | 2002-08-30 | 2003-03-01 | 2003-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-08-30 | 2007-03-01 | 2007-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-08-30 | 2011-03-01 | 2011-08-31 | $7700.00 | Window Closed / Lapsed |