US5970707A
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US
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Exhaust gas purification device for an internal combustion engine
Assignee: Toyota Motor Corp
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Filing: 1998-09-09
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Granted: 1999-10-26
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Expires: 2018-09-09
Abstract
Abstract In an exhaust gas purification device for an internal combustion engine, a three-way catalyst and a NO X occluding and reducing catalyst (a NORC) are disposed in the exhaust gas passage of an engine in this order from the upstream side. A first air-fuel ratio sensor is disposed in the exhaust gas passage between the three-way catalyst and the NORC, and a second air-fuel ratio sensor is disposed in the exhaust gas passage downstream of the NORC. An engine electronic control unit (ECU) changes the operating air-fuel ratio of the engine from a lean air-fuel ratio to a rich air-fuel ratio and a rich air-fuel ratio to a lean air-fuel ratio in order to evaluate the abilities of the three-way catalyst and the NORC. The ECU evaluates the catalytic abilities based on the output of the first air-fuel ratio sensor when the engine air-fuel ratio is changed. Further, the ECU evaluates the catalytic ability and the NO X absorbing capacity of the NORC based on the outputs of the first and the second air-fuel ratio sensor when the engine operating air-fuel ratio is changed. The evaluation of the abilities of both the three-way catalyst and the NORC in one successive changing operation of the engine operating air-fuel ratio is based on only the outputs of the first and the second air-fuel ratio sensor.
Inventors
- 👤 Hiroshi Sawada
- 👤 Junichi Kako
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:56
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9445; B01D53/9454; B01D53/9495; F; F01; F01N; F01N11/00; F01N11/007; F01N13/00; F01N13/009; F01N13/011; F01N3/00; F01N3/08; F01N3/0807; F01N3/0828; F01N3/0842; F02; F02D; F02D41/00; F02D41/02; F02D41/021; F02D41/0235; F02D41/027; F02D41/0275; F02D41/14; F02D41/1438; F02D41/1439; F02D41/1441; F01N2250/00; F01N2250/12; F01N2550/00; F01N2550/02; F01N2550/03; F02D41/1444; F02D41/1454; F02D41/1456; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
300 words
An exhaust gas purification device for an internal combustion engine comprising: a three-way catalyst disposed in the exhaust gas passage of an internal combustion engine; a NO X occluding and reducing catalyst disposed in the exhaust gas passage downstream of the three-way catalyst and absorbing NO X in the exhaust gas when the air-fuel ratio of the exhaust gas flowing into the NO X occluding and reducing catalyst is at a lean air-fuel ratio and releasing and reducing the absorbed NO X when the air-fuel ratio of the exhaust gas flowing into the NO X occluding and reducing catalyst is at a stoichiometric or a rich air-fuel ratio; a first air-fuel ratio sensor disposed in the exhaust gas passage at the position between the three-way catalyst and the NO X occluding and reducing catalyst; a second air-fuel ratio sensor disposed in the exhaust gas passage downstream of the NO X occluding and reducing catalyst; air-fuel ratio control means for switching the air-fuel ratio of the exhaust gas flowing into the three-way catalyst either from a rich air-fuel ratio to a lean air-fuel ratio or from a lean air-fuel ratio to a rich air-fuel ratio; and evaluating means for evaluating the abilities of both of the three-way catalyst and the NO X occluding and reducing catalyst when the air-fuel ratio control means switches the air-fuel ratio of the exhaust gas either from a rich air-fuel ratio to a lean air-fuel ratio or from a lean air-fuel ratio to a rich air-fuel ratio, wherein the evaluating means evaluates the ability of the three-way catalyst based on the output signal of the first air-fuel ratio sensor and evaluates the ability of the NO X occluding and reducing catalyst based on the output signals of both the first and the second air-fuel ratio sensors.
Claim 2
Dependent Claim
300 words
An exhaust gas purification device for an internal combustion engine comprising: a three-way catalyst disposed in the exhaust gas passage of an internal combustion engine; a NO X occluding and reducing catalyst disposed in the exhaust gas passage downstream of the three-way catalyst and absorbing NO X in the exhaust gas when the air-fuel ratio of the exhaust gas flowing into the NO X occluding and reducing catalyst is at a lean air-fuel ratio and releasing and reducing the absorbed NO X when the air-fuel ratio of the exhaust gas flowing into the NO X occluding and reducing catalyst is at a stoichiometric or a rich air-fuel ratio; a first air-fuel ratio sensor disposed in the exhaust gas passage at the position between the three-way catalyst and the NO X occluding and reducing catalyst; a second air-fuel ratio sensor disposed in the exhaust gas passage downstream of the NO X occluding and reducing catalyst; air-fuel ratio control means for switching the air-fuel ratio of the exhaust gas flowing into the three-way catalyst either from a rich air-fuel ratio to a lean air-fuel ratio or from a lean air-fuel ratio to a rich air-fuel ratio; and evaluating means for evaluating the abilities of both of the three-way catalyst and the NO X occluding and reducing catalyst when the air-fuel ratio control means switches the air-fuel ratio of the exhaust gas either from a rich air-fuel ratio to a lean air-fuel ratio or from a lean air-fuel ratio to a rich air-fuel ratio, wherein the evaluating means evaluates the ability of the three-way catalyst based on the output signal of the first air-fuel ratio sensor and evaluates the ability of the NO X occluding and reducing catalyst based on the output signals of both the first and the second air-fuel ratio sensors.
Claim 3
Dependent Claim
81 words
An exhaust gas purification device as set forth in claim 1, wherein the evaluating means evaluates the ability of the three-way catalyst based on the length of the period in which the fist air-fuel ratio sensor outputs a signal corresponding to a stoichiometric air-fuel ratio when the air-fuel ratio control means switches the air-fuel ratio of the exhaust gas either from a rich air-fuel ratio to a lean air-fuel ratio or from a lean air-fuel ratio to a rich air-fuel ratio.
Claim 4
Dependent Claim
69 words
An exhaust gas purification device as set forth in claim 1, wherein the evaluating means evaluates the ability of the three-way catalyst based on the output signals of the first air-fuel ratio sensor when the air-fuel ratio control means switches the air-fuel ratio of the exhaust gas both from a rich air-fuel ratio to a lean air-fuel ratio and from a lean air-fuel ratio to a rich air-fuel ratio.
Claim 5
Dependent Claim
53 words
An exhaust gas purification device as set forth in claim 1, further comprising correcting means for correcting at least one of the abilities of the three-way catalyst and the NO X occluding and reducing catalyst evaluated by the evaluating means based on the condition of the exhaust gas flowing into the three-way catalyst.
Claim 6
Dependent Claim
53 words
An exhaust gas purification device as set forth in claim 2, further comprising correcting means for correcting at least one of the abilities of the three-way catalyst and the NO X occluding and reducing catalyst evaluated by the evaluating means based on the condition of the exhaust gas flowing into the three-way catalyst.
Claim 7
Dependent Claim
53 words
An exhaust gas purification device as set forth in claim 3, further comprising correcting means for correcting at least one of the abilities of the three-way catalyst and the NO X occluding and reducing catalyst evaluated by the evaluating means based on the condition of the exhaust gas flowing into the three-way catalyst.
References Cited (Backward Citations)
JPH0374540A
Cited
JPH0526032A
Cited
JPH05209510A
Cited
JPH05133264A
Cited
JPH05171922A
Cited
JPH06117310A
Cited
US5377484A
Cited
WO1994017291A1
Cited
JPH0814030A
Cited
US5740676A
Cited
JPH08232644A
Cited
US5749222A
Cited
JPH08261041A
Cited
JPH08260949A
Cited
US5713199A
Cited
JPH0988560A
Cited
US5743084A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-10-25 | 2003-04-26 | 2003-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-10-25 | 2007-04-26 | 2007-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-10-25 | 2011-04-26 | 2011-10-26 | $7700.00 | Window Closed / Lapsed |