Patent US5693877A successfully refreshed from Google Patents.
US5693877A
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Evaluating method for NOx eliminating catalyst, an evaluating apparatus therefor, and an efficiency controlling method therefor
Assignee: Hitachi Ltd
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Filing: 1994-06-22
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Granted: 1997-12-02
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Expires: 2014-06-22
Abstract
Abstract In order to prevent a catalyst for an internal combustion engine from experiencing decreased efficiency by deterioration after long time use of the catalyst, the decreased efficiency of the catalyst is determined, and the internal engine is controlled based on results of the determination so as to maintain high efficiency of the catalyst. The catalyst is installed in an exhaust pipe of the engine. Sensors for detecting conditions of exhaust gas both at a upstream side and a downstream side of the catalyst are provided, respectively. As for the sensor, for example, an oxygen sensor whose output varies stepwise at λ=1, or a sensor whose output varies in proportion to air-fuel ratio can be used. Detected values of the sensors are taken into a control unit, catalyst efficiency and deteriorating degree of the catalyst are estimated by comparison of the detected values, and the engine is controlled so that the catalyst efficiency is maximized. A preferable exhaust gas cleaning characteristics of the catalyst can be maintained because the decreased efficiency of the catalyst is determined exactly and the engine is controlled so as to prevent the catalyst from experiencing decrease efficiency.
Inventors
- 👤 Minoru Ohsuga
- 👤 Mamoru Fujieda
- 👤 Nobuo Kurihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:45
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/021; F02D41/0235; B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8696; B01D53/92; B01D53/94; B01D53/9495; F01; F01N; F01N11/00; F01N11/007; F01N2550/00; F01N2550/02; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40; Y10; Y10T; Y10T436/00; Y10T436/17; Y10T436/177692; Y10T436/20; Y10T436/206664; Y10T436/207497; Y10T436/208339; Y10T436/21
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
82 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining oxygen concentration upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition, and evaluating said catalyst by comparing a difference of the determined oxygen concentration upstream and downstream of said catalyst via the sensor.
Claim 2
Dependent Claim
82 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining oxygen concentration upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition, and evaluating said catalyst by comparing a difference of the determined oxygen concentration upstream and downstream of said catalyst via the sensor.
Claim 3
Dependent Claim
96 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining concentration of at least one engine exhaust gas component upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition, and evaluating said catalyst based on a difference in at least one physical parameter of the at least one exhaust gas component concentration upstream and downstream of said catalyst.
Claim 4
Dependent Claim
96 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining concentration of at least one engine exhaust gas component upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition, and evaluating said catalyst based on a difference in at least one physical parameter of the at least one exhaust gas component concentration upstream and downstream of said catalyst.
Claim 5
Dependent Claim
106 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining oxygen concentration upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition, evaluating said catalyst based on a difference of oxygen concentration determined by the sensor in exhaust gas upstream of said catalyst and oxygen concentration determined by the sensor in exhaust gas downstream of said NO x eliminating catalyst which is changed by effects of said catalyst.
Claim 6
Dependent Claim
106 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining oxygen concentration upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition, evaluating said catalyst based on a difference of oxygen concentration determined by the sensor in exhaust gas upstream of said catalyst and oxygen concentration determined by the sensor in exhaust gas downstream of said NO x eliminating catalyst which is changed by effects of said catalyst.
Claim 7
Dependent Claim
98 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining concentration of at least one exhaust gas component upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition in a steady state, and evaluating said catalyst based on a difference of at least one physical parameter of the at least one exhaust gas component upstream and downstream of said catalyst.
Claim 8
Dependent Claim
98 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining concentration of at least one exhaust gas component upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition in a steady state, and evaluating said catalyst based on a difference of at least one physical parameter of the at least one exhaust gas component upstream and downstream of said catalyst.
Claim 9
Dependent Claim
78 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining oxygen concentration upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition, and evaluating said catalyst based on differences of the determined oxygen concentration upstream and downstream of said catalyst.
Claim 10
Dependent Claim
78 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining oxygen concentration upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition, and evaluating said catalyst based on differences of the determined oxygen concentration upstream and downstream of said catalyst.
Claim 11
Dependent Claim
78 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining oxygen concentration upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition, and evaluating said catalyst based on differences of the fluctuation width of an output signal of the sensor.
Claim 12
Dependent Claim
78 words
An evaluating method for determining deterioration of a lean NO x catalyst installed in an exhaust gas system of an internal combustion engine for reducing NO x under a lean air-to-fuel ratio condition, comprising the steps of determining oxygen concentration upstream and downstream of the catalyst with a sensor when the engine is operated under the lean air-to-fuel ratio condition, and evaluating said catalyst based on differences of the fluctuation width of an output signal of the sensor.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2000-12-01 | 2001-06-02 | 2001-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-01 | 2005-06-02 | 2005-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-01 | 2009-06-02 | 2009-12-02 | $7700.00 | Window Closed / Lapsed |