Patent US4747265A successfully refreshed from Google Patents.
US4747265A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Double air-fuel ratio sensor system having improved exhaust emission characteristics
Assignee: Toyota Motor Corp
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Filing: 1986-12-19
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Granted: 1988-05-31
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Expires: 2006-12-19
Abstract
Abstract In a double air-fuel sensor system including two air-fuel ratio sensors upstream and downstream of a catalyst converter provided in an exhaust gas passage, an actual air-fuel ratio is adjusted in accordance with the outputs of the upstream-side and downstream-side air-fuel ratio sensors. Also, when the output of the upstream-side air-fuel ratio sensor is in an abnormal state, an alarm is generated.
Inventors
- 👤 Toshinari Nagai
- 👤 Takatoshi Masui
- 👤 Toshiyasu Katsuno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:24
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1493; F02D41/1495; F02D41/1439; F02D41/1441
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
221 words
A method for controlling an air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter, for detecting a concentration of a specific component in the exhaust gas, comprising the steps of: adjusting an actual air-fuel ratio in accordance with the outputs of said upstream-side and downstream-side air-fuel ratio sensors; determining whether or not the output of said upstream-side air-fuel ratio sensor is in an abnormal state; and generating an alarm when said upstream-side air-fuel ratio sensor is in an abnormal state; wherein said actual air-fuel ratio adjusting step comprises the steps of: calculating a first air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; calculating a second air-fuel ratio correction amount in accordance with the output of said downstream-side air-fuel ratio sensor; and adjusting said actual air-fuel ratio in accordance with said first and second air-fuel ratio correction amounts; wherein said abnormal state determining step comprises a step of determining whether or not said second air-fuel ratio correction amount is within a predetermined range, and determining that said upstream-side air-fuel ratio sensor is in an abnormal state when said second air-fuel ratio correction amount is not within said predetermined range.
Claim 2
Independent Claim
221 words
A method for controlling an air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter, for detecting a concentration of a specific component in the exhaust gas, comprising the steps of: adjusting an actual air-fuel ratio in accordance with the outputs of said upstream-side and downstream-side air-fuel ratio sensors; determining whether or not the output of said upstream-side air-fuel ratio sensor is in an abnormal state; and generating an alarm when said upstream-side air-fuel ratio sensor is in an abnormal state; wherein said actual air-fuel ratio adjusting step comprises the steps of: calculating a first air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; calculating a second air-fuel ratio correction amount in accordance with the output of said downstream-side air-fuel ratio sensor; and adjusting said actual air-fuel ratio in accordance with said first and second air-fuel ratio correction amounts; wherein said abnormal state determining step comprises a step of determining whether or not said second air-fuel ratio correction amount is within a predetermined range, and determining that said upstream-side air-fuel ratio sensor is in an abnormal state when said second air-fuel ratio correction amount is not within said predetermined range.
Claim 3
Independent Claim
225 words
A method for controlling an air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhasut gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said actalyst converter, for detecting a concentration of a specific component in the exhaust gas, comprising the steps of: adjusting an actual air-fuel ratio in accordance with the outputs of said upstream-side and downstream-side air-fuel ratio sensors; determining whether or not the output of said upstream-side air-fuel ratio sensor is in an abnormal state; and generating an alarm when said upstream-side air-fuel ratio sensor is in an abnormal state; wherein said actual air-fuel ratio adjusting step comprises the steps of: calculating an air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; and calculating an air-fuel ratio feedback control parameter in accordance with the output of said downstream-side air-fuel ratio sensor; and adjusting said actual air-fuel ratio in accordance with said air-fuel ratio correction amount and said air-fuel ratio feedback control parameter; wherein said abnormal state determining step comprises a step of determining whether or not said air-fuel ratio feedback control parameter is within a predetermined range, and determining that said upsteam-side air-fuel ratio sensor is in an abnormal state when said air-fuel ratio feedback control parameter is not within said predetermined range.
Claim 4
Independent Claim
225 words
A method for controlling an air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhasut gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said actalyst converter, for detecting a concentration of a specific component in the exhaust gas, comprising the steps of: adjusting an actual air-fuel ratio in accordance with the outputs of said upstream-side and downstream-side air-fuel ratio sensors; determining whether or not the output of said upstream-side air-fuel ratio sensor is in an abnormal state; and generating an alarm when said upstream-side air-fuel ratio sensor is in an abnormal state; wherein said actual air-fuel ratio adjusting step comprises the steps of: calculating an air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; and calculating an air-fuel ratio feedback control parameter in accordance with the output of said downstream-side air-fuel ratio sensor; and adjusting said actual air-fuel ratio in accordance with said air-fuel ratio correction amount and said air-fuel ratio feedback control parameter; wherein said abnormal state determining step comprises a step of determining whether or not said air-fuel ratio feedback control parameter is within a predetermined range, and determining that said upsteam-side air-fuel ratio sensor is in an abnormal state when said air-fuel ratio feedback control parameter is not within said predetermined range.
Claim 5
Dependent Claim
85 words
A method as set forth in claim 2, wherein said air-fuel ratio feedback control parameter is defined by a lean skip amount by which said air-fuel ratio correction amount is skipped down when the output of said upstream-side air-fuel ratio sensor is switched from the lean side to the rich side and a rich skip amount by which said air-fuel ratio correction amount is skipped up when the output of said downstream-side air-fuel ratio sensor is switched from the rich side to the lean side.
Claim 6
Dependent Claim
75 words
A method as set forth in claim 2, wherein said air-fuel ratio feedback control parameter is defined by a lean integration amount by which said air-fuel ratio correction amount is gradually decreased when the output of said upstream-side air-fuel ratio sensor is on the rich side and a rich integration amount by which said air-fuel ratio correction amount is gradually increased when the output of said upstream-side air-fuel ratio sensor is on the lean side.
Claim 7
Dependent Claim
67 words
A method as set forth in claim 2, wherein said air-fuel ratio feedback control parameter is determined by a rich delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the lean side to the rich side and a lean delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the rich side to the lean side.
Claim 8
Dependent Claim
49 words
A method as set forth in claim 2, wherein said air-fuel ratio feedback control parameter is determined by a reference voltage with which the output of said upstream-side air-fuel ratio sensor is compared, thereby determining whether the air-fuel ratio is on the rich side or on the lean side.
Claim 9
Independent Claim
244 words
An apparatus for contorlling an air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter, for detecting a concentration of a specific component in the exhaust gas, comprising: means for adjusting an actual air-fuel ratio in accordance with outputs of said upstream-side and downstream-side air-fuel ratio sensors; means for determining whether or not the output of said upstream-side air-fuel ratio sensor is in an abnormal state; and means for generating an alarm when said upstream-side air-fuel ratio sensor is in an abnormal state; wherein said actual air-fuel ratio adjusting means comprises: means for calculating a first air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; means for calculating a second air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; and means for calculating a second air-fuel ratio correction amount in accordance with the output of said downstream-side air-fuel ratio sensor, thereby adjusting said actual air-fuel ratio in accordance with said first and second air-fuel ratio correction amounts; wherein said abnormal state determining means comprises means for determining whether or not said second air-fuel ratio correction amount is within a predetermined range, thereby determining that said upstream-side air-fuel ratio sensor is in an abnormal state when said second air-fuel ratio correction amount is not within said predetermined range.
Claim 10
Independent Claim
244 words
An apparatus for contorlling an air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter, for detecting a concentration of a specific component in the exhaust gas, comprising: means for adjusting an actual air-fuel ratio in accordance with outputs of said upstream-side and downstream-side air-fuel ratio sensors; means for determining whether or not the output of said upstream-side air-fuel ratio sensor is in an abnormal state; and means for generating an alarm when said upstream-side air-fuel ratio sensor is in an abnormal state; wherein said actual air-fuel ratio adjusting means comprises: means for calculating a first air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; means for calculating a second air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; and means for calculating a second air-fuel ratio correction amount in accordance with the output of said downstream-side air-fuel ratio sensor, thereby adjusting said actual air-fuel ratio in accordance with said first and second air-fuel ratio correction amounts; wherein said abnormal state determining means comprises means for determining whether or not said second air-fuel ratio correction amount is within a predetermined range, thereby determining that said upstream-side air-fuel ratio sensor is in an abnormal state when said second air-fuel ratio correction amount is not within said predetermined range.
Claim 11
Independent Claim
227 words
An apparatus for controlling an air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter, for detecting a concentration of a specific component in the exhaust gas, comprising: means for adjusting an actual air-fuel ratio in accordance with outputs of said upstream-side and downstream-side air-fuel ratio sensors; means for determining whether or not the output of said upstream-side air-fuel ratio sensor is in an abnormal state; and means for generating an alarm when said upstream-side air-fuel ratio sensor is in an abnormal state; wherein said actual air-fuel ratio adjusting means comprises: means for calculating an air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; and means for calculating an air-fuel ratio feedback control parameter in accordance with the output of said downstream-side air-fuel ratio sensor, thereby adjusting said actual air-fuel ratio in accordance with said air-fuel ratio correction amount and said air-fuel ratio feedback control parameter; wherein said abnormal state determining means comprises means for determining whether or not said air-fuel ratio feedback control prameter is within a predetermined range, thereby determining that said upstream-side air-fuel ratio sensor is in an abnormal state when said air-fuel ratio feedback control parameter is not within said predetermined range.
Claim 12
Independent Claim
227 words
An apparatus for controlling an air-fuel ratio in an internal combustion engine having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of said catalyst converter, for detecting a concentration of a specific component in the exhaust gas, comprising: means for adjusting an actual air-fuel ratio in accordance with outputs of said upstream-side and downstream-side air-fuel ratio sensors; means for determining whether or not the output of said upstream-side air-fuel ratio sensor is in an abnormal state; and means for generating an alarm when said upstream-side air-fuel ratio sensor is in an abnormal state; wherein said actual air-fuel ratio adjusting means comprises: means for calculating an air-fuel ratio correction amount in accordance with the output of said upstream-side air-fuel ratio sensor; and means for calculating an air-fuel ratio feedback control parameter in accordance with the output of said downstream-side air-fuel ratio sensor, thereby adjusting said actual air-fuel ratio in accordance with said air-fuel ratio correction amount and said air-fuel ratio feedback control parameter; wherein said abnormal state determining means comprises means for determining whether or not said air-fuel ratio feedback control prameter is within a predetermined range, thereby determining that said upstream-side air-fuel ratio sensor is in an abnormal state when said air-fuel ratio feedback control parameter is not within said predetermined range.
Claim 13
Dependent Claim
85 words
An apparatus as set forth in claim 8, wherein said air-fuel ratio feedback control parameter is defined by a lean skip amount by which said air-fuel ratio correction amount is skipped down when the output of said upstream-side air-fuel ratio sensor is switched from the lean side to the rich side and a rich skip amount by which said air-fuel ratio correction amount is skipped up when the output of said downstream-side air-fuel ratio sensor is switched from the rich side to the lean side.
Claim 14
Dependent Claim
75 words
An apparatus as set forth in claim 8, wherein said air-fuel ratio feedback control parameter is defined by a lean integration amount by which said air-fuel ratio correction amount is gradually decreased when the output of said upstream-side air-fuel ratio sensor is on the rich side and a rich integration amount by which said air-fuel ratio correction amount is gradually increased when the output of said upstream-side air-fuel ratio sensor is on the lean side.
Claim 15
Dependent Claim
67 words
An apparatus as set forth in claim 8, wherein said air-fuel ratio feedback control parameter is determined by a rich delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the lean side to the rich side and a lean delay time period for delaying the output of said upstream-side air-fuel ratio sensor switched from the rich side to the lean side.
Claim 16
Dependent Claim
49 words
An apparatus as set forth in claim 8, wherein said air-fuel ratio feedback control parameter is determined by a reference voltage with which the output of said upstream-side air-fuel ratio sensor is compared, thereby determining whether the air-fuel ratio is on the rich side or on the lean side.
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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) | 1991-05-31 | 1991-11-30 | 1992-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-31 | 1995-11-30 | 1996-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-31 | 1999-11-30 | 2000-05-31 | $7700.00 | Window Closed / Lapsed |