US5953907A
Expired / Lapsed
US
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Method of controlling an engine exhaust gas system and method of detecting deterioration of catalyst/adsorbing means
Assignee: NGK Insulators Ltd
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Filing: 1997-06-16
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Granted: 1999-09-21
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Expires: 2017-06-16
Abstract
Abstract In a method of controlling an exhaust gas system of an internal combustion engine including a nitrogen oxide reducing catalyst capable of adsorbing nitrogen oxide under a lean atmosphere and a nitrogen oxide sensor disposed downstream of the nitrogen oxide reducing catalyst, the nitrogen oxide reducing catalyst and the nitrogen oxide sensor are disposed in the exhaust gas system operated mainly under a lean condition, respectively. An output value of the nitrogen oxide sensor is compared with a predetermined value, and an operation condition of the internal combustion engine is temporarily changed into a stoichiometric condition or a rich condition, or a fuel is injected upstream of the nitrogen oxide reducing catalyst, so that the nitrogen oxide adsorbed to the nitrogen oxide reducing catalyst is detached or decomposed, and again the internal combustion engine is operated under the lean condition.
Inventors
- 👤 Nobuhide Kato
- 👤 Hiroshi Kurachi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:32
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1444; F02D41/146; B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9431; B01D53/9495; F01; F01N; F01N11/00; F01N3/00; F01N3/08; F01N3/0807; F01N3/0814; F01N3/0828; F01N3/0842; F01N3/0871; F02D41/021; F02D41/0235; F02D41/027; F02D41/0275; F02D41/1439; F02D41/1441; F02D41/1463; F01N2250/00; F01N2250/12; F01N2430/00; F01N2430/06; F01N2550/00; F01N2550/02; F01N2550/03; F01N2610/00; F01N2610/03; F02B; F02B1/00; F02B1/02; F02B1/04; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
160 words
A method of controlling an exhaust gas system of an internal combustion engine which operates mainly under a lean condition, which system comprises a nitrogen oxide reducing catalyst capable of adsorbing nitrogen oxide under a lean atmosphere and a nitrogen oxide sensor disposed downstream of the nitrogen oxide reducing catalyst, said method comprising the steps of: (a) monitoring the output value of said nitrogen oxide sensor, (b) comparing said output value with a predetermined value and determining when nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is to be detached or decomposed, (c) changing temporarily in response to the determination made in step (b) the operation condition of said internal combustion engine into a stoichiometric condition or a rich condition so that the nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is detached or decomposed, and (d) returning the operational condition back to its normal value whereby said internal combustion engine is operating again under a lean condition.
Claim 2
Independent Claim
160 words
A method of controlling an exhaust gas system of an internal combustion engine which operates mainly under a lean condition, which system comprises a nitrogen oxide reducing catalyst capable of adsorbing nitrogen oxide under a lean atmosphere and a nitrogen oxide sensor disposed downstream of the nitrogen oxide reducing catalyst, said method comprising the steps of: (a) monitoring the output value of said nitrogen oxide sensor, (b) comparing said output value with a predetermined value and determining when nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is to be detached or decomposed, (c) changing temporarily in response to the determination made in step (b) the operation condition of said internal combustion engine into a stoichiometric condition or a rich condition so that the nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is detached or decomposed, and (d) returning the operational condition back to its normal value whereby said internal combustion engine is operating again under a lean condition.
Claim 3
Dependent Claim
63 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 1, wherein the monitoring of the output value of said nitrogen oxide sensor further comprises monitoring of a nitrogen oxide sensor which is disposed upstream of said nitrogen oxide reducing catalyst in addition to said nitrogen oxide sensor disposed downstream of said nitrogen oxide reducing catalyst.
Claim 4
Dependent Claim
38 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 1, wherein start of operation under the lean condition is executed based on the output value of said nitrogen oxide sensor.
Claim 5
Dependent Claim
45 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 1, wherein start of operation under the lean condition is executed based on a time programed in advance based on an operation condition of said internal combustion engine.
Claim 6
Dependent Claim
151 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 1, wherein said nitrogen oxide sensor comprises a base made of an oxygen ion conductive solid electrolyte; an electrochemical pump cell formed of an inner pump electrode and an outer pump electrode disposed inside and outside of said base; a main pump means for pumping oxygen contained in measured gas introduced from an outside space based on a control voltage applied between said inner pump electrode and said outer pump electrode; a pair of detection electrodes, one of which is disposed at a side where the measured gas pumped by said main pump means is introduced; and an electric signal conversion means for generating an electric signal in accordance with an amount of oxygen generated by decomposition or reduction of NOx contained in the measured gas after being pumped by said main pump means.
Claim 7
Dependent Claim
71 words
A method of detecting deterioration of a catalyst, characterized in that in the method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 1, deterioration of said nitrogen oxide reducing catalyst is detected based on the output value of said nitrogen oxide sensor, a period of time of continuation of a lean condition, or a repetition period of the lean condition and a rich condition.
Claim 8
Independent Claim
132 words
A method of controlling an exhaust gas system of an internal combustion engine which operates mainly under a lean condition, which system comprises a nitrogen oxide reducing catalyst capable of adsorbing nitrogen oxide under a lean atmosphere and a nitrogen oxide sensor disposed downstream of the nitrogen oxide reducing catalyst, said method comprising the steps of: (a) monitoring the output value of said nitrogen oxide sensor, (b) comparing said output value with a predetermined value and determining when nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is to be detached or decomposed, (c) injecting a fuel upstream of said nitrogen oxide reducing catalyst so that the nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is detached or decomposed, and (d) operating again said internal combustion engine under a lean condition.
Claim 9
Independent Claim
132 words
A method of controlling an exhaust gas system of an internal combustion engine which operates mainly under a lean condition, which system comprises a nitrogen oxide reducing catalyst capable of adsorbing nitrogen oxide under a lean atmosphere and a nitrogen oxide sensor disposed downstream of the nitrogen oxide reducing catalyst, said method comprising the steps of: (a) monitoring the output value of said nitrogen oxide sensor, (b) comparing said output value with a predetermined value and determining when nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is to be detached or decomposed, (c) injecting a fuel upstream of said nitrogen oxide reducing catalyst so that the nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is detached or decomposed, and (d) operating again said internal combustion engine under a lean condition.
Claim 10
Dependent Claim
63 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 7, wherein the monitoring of the output value of said nitrogen oxide sensor further comprises monitoring of a nitrogen oxide sensor which is disposed upstream of said nitrogen oxide reducing catalyst in addition to said nitrogen oxide sensor disposed downstream of said nitrogen oxide reducing catalyst.
Claim 11
Dependent Claim
38 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 7, wherein start of operation under the lean condition is executed based on the output value of said nitrogen oxide sensor.
Claim 12
Dependent Claim
45 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 7, wherein start of operation under the lean condition is executed based on a time programmed in advance based on an operation condition of said internal combustion engine.
Claim 13
Dependent Claim
151 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 7, wherein said nitrogen oxide sensor comprises a base made of an oxygen ion conductive solid electrolyte; an electrochemical pump cell formed of an inner pump electrode and an outer pump electrode disposed inside and outside of said base; a main pump means for pumping oxygen contained in measured gas introduced from an outside space based on a control voltage applied between said inner pump electrode and said outer pump electrode; a pair of detection electrodes, one of which is disposed at a side where the measured gas pumped by said main pump means is introduced; and an electric signal conversion means for generating an electric signal in accordance with an amount of oxygen generated by decomposition or reduction of NOx contained in the measured gas after being pumped by said main pump means.
Claim 14
Dependent Claim
71 words
A method of detecting deterioration of a catalyst, characterized in that in the method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 7, deterioration of said nitrogen oxide reducing catalyst is detected based on the output value of said nitrogen oxide sensor, a period of time of continuation of a lean condition, or a repetition period of the lean condition and a rich condition.
Claim 15
Independent Claim
169 words
A method of controlling an exhaust gas system of an internal combustion engine which operates mainly under a lean condition, which system comprises an adsorbing means capable of adsorbing nitrogen oxide under a lean atmosphere, a nitrogen oxide reducing catalyst disposed downstream of the adsorbing means or integrally with the adsorbing means, and a nitrogen oxide sensor disposed downstream of the adsorbing means, said method comprising the steps of: (a) monitoring the output value of said nitrogen oxide sensor, (b) comparing said output value with a predetermined value and determining when nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is to be detached or decomposed, (c) changing temporarily in response to the determination made in step (b) the operation condition of said internal combustion engine into a stoichiometric or rich condition so that the nitrogen oxide adsorbed to said adsorbing means is detached or decomposed, and (d) returning the operational condition back to its normal value whereby said internal combustion engine is operating again under a lean condition.
Claim 16
Independent Claim
169 words
A method of controlling an exhaust gas system of an internal combustion engine which operates mainly under a lean condition, which system comprises an adsorbing means capable of adsorbing nitrogen oxide under a lean atmosphere, a nitrogen oxide reducing catalyst disposed downstream of the adsorbing means or integrally with the adsorbing means, and a nitrogen oxide sensor disposed downstream of the adsorbing means, said method comprising the steps of: (a) monitoring the output value of said nitrogen oxide sensor, (b) comparing said output value with a predetermined value and determining when nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is to be detached or decomposed, (c) changing temporarily in response to the determination made in step (b) the operation condition of said internal combustion engine into a stoichiometric or rich condition so that the nitrogen oxide adsorbed to said adsorbing means is detached or decomposed, and (d) returning the operational condition back to its normal value whereby said internal combustion engine is operating again under a lean condition.
Claim 17
Dependent Claim
43 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 13, wherein a nitrogen oxide sensor is disposed upstream of said adsorbing means in addition to said nitrogen oxide sensor disposed downstream of said adsorbing means.
Claim 18
Dependent Claim
38 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 13, wherein start of operation under the lean condition is executed based on the output value of said nitrogen oxide sensor.
Claim 19
Dependent Claim
45 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 13, wherein start of operation under the lean condition is executed based on a time programmed in advance based on an operation condition of said internal combustion engine.
Claim 20
Dependent Claim
151 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 13, wherein said nitrogen oxide sensor comprises a base made of an oxygen ion conductive solid electrolyte; an electrochemical pump cell formed of an inner pump electrode and an outer pump electrode disposed inside and outside of said base; a main pump means for pumping oxygen contained in measured gas introduced from an outside space based on a control voltage applied between said inner pump electrode and said outer pump electrode; a pair of detection electrodes, one of which is disposed at a side where the measured gas pumped by said main pump means is introduced; and an electric signal conversion means for generating an electric signal in accordance with an amount of oxygen generated by decomposition or reduction of NOx contained in the measured gas after being pumped by said main pump means.
Claim 21
Dependent Claim
76 words
A method of detecting deterioration of a catalyst/adsorbing means, characterized in that in the method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 13, deterioration of said nitrogen oxide reducing catalyst or said adsorbing means is detected based on the output value of said nitrogen oxide sensor, a period of time of continuation of a lean condition, or a repetition period of the lean condition and a rich condition.
Claim 22
Independent Claim
141 words
A method of controlling an exhaust gas system of an internal combustion engine which operates mainly under a lean condition, which system comprises an adsorbing means capable of adsorbing nitrogen oxide under a lean atmosphere, a nitrogen oxide reducing catalyst disposed downstream of the adsorbing means or integrally with the adsorbing means, and a nitrogen oxide sensor disposed downstream of the adsorbing means, said method comprising the steps of: (a) monitoring the output value of said nitrogen oxide sensor, (b) comparing said output value with a predetermined value and determining when nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is to be detached or decomposed, (c) injecting a fuel upstream of said adsorbing means so that the nitrogen oxide adsorbed to said adsorbing means is detached or decomposed, and (d) again operating said internal combustion engine under a lean condition.
Claim 23
Independent Claim
141 words
A method of controlling an exhaust gas system of an internal combustion engine which operates mainly under a lean condition, which system comprises an adsorbing means capable of adsorbing nitrogen oxide under a lean atmosphere, a nitrogen oxide reducing catalyst disposed downstream of the adsorbing means or integrally with the adsorbing means, and a nitrogen oxide sensor disposed downstream of the adsorbing means, said method comprising the steps of: (a) monitoring the output value of said nitrogen oxide sensor, (b) comparing said output value with a predetermined value and determining when nitrogen oxide adsorbed to said nitrogen oxide reducing catalyst is to be detached or decomposed, (c) injecting a fuel upstream of said adsorbing means so that the nitrogen oxide adsorbed to said adsorbing means is detached or decomposed, and (d) again operating said internal combustion engine under a lean condition.
Claim 24
Dependent Claim
43 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 19, wherein a nitrogen oxide sensor is disposed upstream of said adsorbing means in addition to said nitrogen oxide sensor disposed downstream of said adsorbing means.
Claim 25
Dependent Claim
38 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 19, wherein start of operation under the lean condition is executed based on the output value of said nitrogen oxide sensor.
Claim 26
Dependent Claim
45 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 19, wherein start of operation under the lean condition is executed based on a time programmed in advance based on an operation condition of said internal combustion engine.
Claim 27
Dependent Claim
151 words
A method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 19, wherein said nitrogen oxide sensor comprises a base made of an oxygen ion conductive solid electrolyte; an electrochemical pump cell formed of an inner pump electrode and an outer pump electrode disposed inside and outside of said base; a main pump means for pumping oxygen contained in measured gas introduced from an outside space based on a control voltage applied between said inner pump electrode and said outer pump electrode; a pair of detection electrodes, one of which is disposed at a side where the measured gas pumped by said main pump means is introduced; and an electric signal conversion means for generating an electric signal in accordance with an amount of oxygen generated by decomposition or reduction of NOx contained in the measured gas after being pumped by said main pump means.
Claim 28
Dependent Claim
76 words
A method of detecting deterioration of a catalyst/adsorbing means, characterized in that in the method of controlling an exhaust gas system of an internal combustion engine as claimed in claim 19, deterioration of said nitrogen oxide reducing catalyst or said adsorbing means is detected based on the output value of said nitrogen oxide sensor, a period of time of continuation of a lean condition, or a repetition period of the lean condition and a rich condition.
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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) | 2002-09-20 | 2003-03-22 | 2003-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-09-20 | 2007-03-22 | 2007-09-21 | $3760.00 | Window Closed / Lapsed |
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