Patent US5970707A successfully refreshed from Google Patents.
US5970707A
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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 10:55
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.
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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) | 2002-10-25 | 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 |