US6185933B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exhaust emission control device for engine
Assignee: Nissan Motor Co Ltd
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Filing: 1999-06-15
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Granted: 2001-02-13
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Expires: 2019-06-15
Abstract
Abstract A three-way catalyst ( 9 ) which has an oxygen storage capacity is disposed in an exhaust passage ( 3 ) and HC adsorbent-catalysts ( 10, 11 ) which can adsorb and oxidize HC are disposed further downstream. If release of HC from the HC adsorbent-catalysts is determined, the lean level of an air-fuel ratio is increased temporarily after HC release is commenced. Thereafter the air-fuel ratio is controlled to a lower lean level which corresponds to an HC concentration during release. In this way, after lean control is commenced, the three-way catalyst is saturated in a short time and oxygen is sent to the HC adsorbent-catalysts ( 10, 11 ) and released HC is oxidized.
Inventors
- 👤 Mikio Tsuzuki
- 👤 Ritsuo Sato
- 👤 Kimiyoshi Nishizawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:04
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9445; B01D53/9454; B01D53/9495; F; F01; F01N; F01N13/00; F01N13/009; F01N3/00; F01N3/08; F01N3/0807; F01N3/0814; F01N3/0828; F01N3/0835; F02; F02D; F02D41/00; F02D41/02; F02D41/021; F02D41/0235; F02D41/027; F02D41/0295; F01N2570/00; F01N2570/16; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
126 words
An emission control device for an engine comprising: a catalyst disposed in an exhaust passage, the catalyst storing oxygen; a hydrocarbon adsorbent-catalyst disposed in the exhaust passage at a location downstream of the catalyst; and a control unit that controls an air-fuel ratio of the engine, wherein the control unit is programmed. to determine release of hydrocarbons from the hydrocarbon adsorbent-catalyst based on the hydrocarbon adsorbent-catalyst temperature to control the air-fuel ratio to a first lean air-fuel ratio when the hydrocarbon adsorbent-catalyst starts to release hydrocarbons, and to control an air-fuel ratio to a second lean air-fuel ratio after controlling to the first lean air-fuel ratio during hydrocarbon release by the hydrocarbon adsorbent-catalyst; the first lean air-fuel ratio being leaner than the second lean air-fuel ratio.
Claim 2
Dependent Claim
126 words
An emission control device for an engine comprising: a catalyst disposed in an exhaust passage, the catalyst storing oxygen; a hydrocarbon adsorbent-catalyst disposed in the exhaust passage at a location downstream of the catalyst; and a control unit that controls an air-fuel ratio of the engine, wherein the control unit is programmed. to determine release of hydrocarbons from the hydrocarbon adsorbent-catalyst based on the hydrocarbon adsorbent-catalyst temperature to control the air-fuel ratio to a first lean air-fuel ratio when the hydrocarbon adsorbent-catalyst starts to release hydrocarbons, and to control an air-fuel ratio to a second lean air-fuel ratio after controlling to the first lean air-fuel ratio during hydrocarbon release by the hydrocarbon adsorbent-catalyst; the first lean air-fuel ratio being leaner than the second lean air-fuel ratio.
Claim 3
Dependent Claim
47 words
An emission control device for an engine according to claim 1 , wherein the control unit is further programmed to determine the first lean air-fuel ratio and to determine a continuation time controlling to the first lean air-fuel depending on an oxygen storage capacity of the catalyst.
Claim 4
Dependent Claim
74 words
An emission control device for an engine according to claim 2 , further comprising a air-fuel sensor disposed in the exhaust passage at a location downstream of the catalyst; and wherein the control unit is further programmed to determine a level of deterioration of the catalyst depending on an output of the air-fuel sensor and to calculate the oxygen storage capacity of the catalyst depending on the determined level of deterioration of the catalyst.
Claim 5
Dependent Claim
49 words
An emission control device for an engine according to claim 1 , wherein the control unit is further programmed to determine the first lean air-fuel ratio and to determine a continuation time controlling to the first lean air-fuel ratio depending on a current oxygen storage amount of the catalyst.
Claim 6
Dependent Claim
63 words
An emission control device for an engine according to claim 4 , further comprising a linear air-fuel sensor disposed in the exhaust passage at a location upstream of the catalyst; and control unit is further programmed to calculate the current oxygen storage amount of the catalyst depending on a difference between a stoichiometric air-fuel ratio and an output of the linear air-fuel ratio.
Claim 7
Dependent Claim
59 words
An emission control device for an engine according to claim 1 wherein the control unit is further programmed to determine the first lean air-fuel ratio and to determine a continuation time controlling to the first lean air-fuel ratio depending on the difference between an oxygen storage capacity of the catalyst and a current oxygen storage amount of the catalyst.
Claim 8
Dependent Claim
35 words
An emission control device for an engine according to claim 1 wherein the control unit is further programmed to reduce a lean level of the first lean air-fuel ratio according to deterioration of the catalyst.
Claim 9
Dependent Claim
37 words
An emission control device for an engine according to claim 1 wherein the control unit is further programmed to estimate the temperature of at least one of the catalysts depending on engine rotation speed and engine load.
Claim 10
Dependent Claim
112 words
An emission control device for an engine comprising: a catalyst disposed in an exhaust passage, the catalyst storing oxygen; a hydrocarbon adsorbent-catalyst disposed in the exhaust passage at a location downstream of the catalyst; and means for determining relase of hydrocarbons from the hydrocarbon adsorbent-catalyst based on the hydrocarbon adsorbent-catalyst temperature; means for controlling the air-fuel ratio to a first lean air-fuel ratio when the hydrocarbon adsorbent-catalyst starts to release hydrocarbons; and means for controlling an air-fuel ratio to a second lean air-fuel ratio after controlling to the first lean air-fuel ratio during hydrocarbon release by the hydrocarbon adsorbent-catalyst; the first lean air-fuel ratio being leaner than the second lean air-fuel ratio.
Claim 11
Dependent Claim
112 words
An emission control device for an engine comprising: a catalyst disposed in an exhaust passage, the catalyst storing oxygen; a hydrocarbon adsorbent-catalyst disposed in the exhaust passage at a location downstream of the catalyst; and means for determining relase of hydrocarbons from the hydrocarbon adsorbent-catalyst based on the hydrocarbon adsorbent-catalyst temperature; means for controlling the air-fuel ratio to a first lean air-fuel ratio when the hydrocarbon adsorbent-catalyst starts to release hydrocarbons; and means for controlling an air-fuel ratio to a second lean air-fuel ratio after controlling to the first lean air-fuel ratio during hydrocarbon release by the hydrocarbon adsorbent-catalyst; the first lean air-fuel ratio being leaner than the second lean air-fuel ratio.
Claim 12
Dependent Claim
243 words
An emission control device for an engine comprising: a catalyst disposed in an exhaust passage, the catalyst storing oxygen; a first hydrocarbon adsorbent-catalyst disposed in the exhaust passage at a location downstream of the catalyst, the first hydrocarbon adsorbent-catalyst storing oxgen; a second hydrocarbon adsorbent-catalyst disposed in the exhaust passage at a location downstream of the first hydrocarbon adsorbent catalyst; and a control unit that controls an air-fuel ratio of the engine, wherein the control unit is programmed to determine release of hydrocarbons from the first and second hydrocarbon adsorbent-catalyst based on the respective hydrocarbon adsorbent-catalyst temperatures. to control the air-fuel ratio to a first lean air-fuel ratio according to remaining oxygen storage capacity of the catalyst when the first hydrocarbon adsorbent-catalyst starts to release hydrocarbons, and to control an air-fuel ratio to a second lean air-fuel ratio after controlling to the first lean air-fuel ratio during hydrocarbon release by the first hydrocarbon adsorbent-catalyst; the first lean air-fuel ratio being leaner than the second lean air-fuel ratio and to control the air-fuel ratio to a third lean air-fuel ratio according to remaining oxygen storage capacity of the catalyst and the first hydrocarbon adsorbent-catalyst when the second hydrocarbon adsorbent-catalyst starts to release hydrocarbons, and to control an air-fuel ratio to a fourth lean air-fuel ratio after controlling to the third lean air-fuel ratio during hydrocarbon release by the second hydrocarbon adsorbent-catalyst; the third lean air-fuel ratio being leaner than the fourth lean air-fuel ratio.
Claim 13
Dependent Claim
243 words
An emission control device for an engine comprising: a catalyst disposed in an exhaust passage, the catalyst storing oxygen; a first hydrocarbon adsorbent-catalyst disposed in the exhaust passage at a location downstream of the catalyst, the first hydrocarbon adsorbent-catalyst storing oxgen; a second hydrocarbon adsorbent-catalyst disposed in the exhaust passage at a location downstream of the first hydrocarbon adsorbent catalyst; and a control unit that controls an air-fuel ratio of the engine, wherein the control unit is programmed to determine release of hydrocarbons from the first and second hydrocarbon adsorbent-catalyst based on the respective hydrocarbon adsorbent-catalyst temperatures. to control the air-fuel ratio to a first lean air-fuel ratio according to remaining oxygen storage capacity of the catalyst when the first hydrocarbon adsorbent-catalyst starts to release hydrocarbons, and to control an air-fuel ratio to a second lean air-fuel ratio after controlling to the first lean air-fuel ratio during hydrocarbon release by the first hydrocarbon adsorbent-catalyst; the first lean air-fuel ratio being leaner than the second lean air-fuel ratio and to control the air-fuel ratio to a third lean air-fuel ratio according to remaining oxygen storage capacity of the catalyst and the first hydrocarbon adsorbent-catalyst when the second hydrocarbon adsorbent-catalyst starts to release hydrocarbons, and to control an air-fuel ratio to a fourth lean air-fuel ratio after controlling to the third lean air-fuel ratio during hydrocarbon release by the second hydrocarbon adsorbent-catalyst; the third lean air-fuel ratio being leaner than the fourth lean air-fuel ratio.
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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) | 2004-02-13 | 2004-08-14 | 2005-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-02-13 | 2008-08-14 | 2009-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-02-13 | 2012-08-14 | 2013-02-13 | $7700.00 | Window Closed / Lapsed |