Patent US5650851A successfully refreshed from Google Patents.
US5099646A
Expired / Lapsed
US
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Air-fuel ratio feedback control system having a single air-fuel ratio sensor downstream of a three-way catalyst converter
Assignee: Toyota Motor Corp
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Filing: 1991-07-02
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Granted: 1992-03-31
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Expires: 2011-07-02
Abstract
Abstract In an air-fuel ratio feedback control system including a single air-fuel ratio sensor downstream of a three-way catalyst converter, the coarse-adjusting term and the O 2 adjusting term are calculated in accordance with the air-fuel ratio sensor, and an initial timing of the O 2 adjusting term is delayed when the catalyst converter is deteriorated, to thus improve the drivability of a vehicle.
Inventors
- 👤 Mitsuhiro Nada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:44
CPC Classifications
F; F01; F01N; F01N11/00; F01N11/007; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1477; F02D41/24; F02D41/2406; F02D41/2425; F02D41/2429; F02D41/2451; F02D41/2454; F02D41/2458; F01N2900/00; F01N2900/04; F01N2900/0422; F02D41/1444; F02D41/1454; F02D41/1456; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
205 words
A method of controlling an air-fuel ratio in an internal combustion engine having a three-way catalyst converter for removing pollutants in the exhaust gas of said engine and an air-fuel ratio sensor disposed downstream of said three-way catalyst converter for detecting a specific component in the exhaust gas, said method comprising the steps of: greatly changing a coarse-adjusting term when the output of said air-fuel ratio sensor is inverted from the rich state to the lean state and vice versa, and gradually changing said coarse-adjusting term when the output of said air-fuel ratio sensor remains in the same state; greatly changing a proportional amount of an O 2 storage adjusting term when the output of said air-fuel ratio sensor is under a first threshold value which is smaller than a value corresponding to the stoichiometric air-fuel ratio or over a second threshold value which is larger than a value corresponding to the stoichiometric air-fuel ratio; determining whether or not said catalyst converter is deteriorated; delaying an initiating timing of said O 2 storage term for a predetermined interval when said catalyst convertor is determined to be deteriorated; and adjusting an actual air-fuel ratio in accordance with said coarse-adjusting term and said O 2 storage term.
Claim 2
Independent Claim
205 words
A method of controlling an air-fuel ratio in an internal combustion engine having a three-way catalyst converter for removing pollutants in the exhaust gas of said engine and an air-fuel ratio sensor disposed downstream of said three-way catalyst converter for detecting a specific component in the exhaust gas, said method comprising the steps of: greatly changing a coarse-adjusting term when the output of said air-fuel ratio sensor is inverted from the rich state to the lean state and vice versa, and gradually changing said coarse-adjusting term when the output of said air-fuel ratio sensor remains in the same state; greatly changing a proportional amount of an O 2 storage adjusting term when the output of said air-fuel ratio sensor is under a first threshold value which is smaller than a value corresponding to the stoichiometric air-fuel ratio or over a second threshold value which is larger than a value corresponding to the stoichiometric air-fuel ratio; determining whether or not said catalyst converter is deteriorated; delaying an initiating timing of said O 2 storage term for a predetermined interval when said catalyst convertor is determined to be deteriorated; and adjusting an actual air-fuel ratio in accordance with said coarse-adjusting term and said O 2 storage term.
Claim 3
Dependent Claim
25 words
A method as set forth in claim 1, wherein said initiating timing is varied in accordance with a degree of deterioration of said catalyst converter.
Claim 4
Dependent Claim
20 words
A method as set forth in claim 1, further comprising a step of gradually changing said O 2 storage term.
Claim 5
Dependent Claim
75 words
A method as set forth in claim 1, wherein said catalyst converter deterioration determining step comprises a step of: determining whether or not an inverting interval, which is an interval from a time at which the output of the said air-fuel ratio sensor is inverted from the rich side to the lean side or vice versa to a time at which it is again inverted in the same direction, is shorter than a predetermined value.
Claim 6
Dependent Claim
39 words
A method as set forth in claim 1, wherein said catalyst converter deterioration determining step comprises a step of: determining whether or not an amplitude of said output of said air-fuel ratio sensor is larger than a predetermined value.
Claim 7
Dependent Claim
38 words
A method as set forth in claim 1, further comprising a step of generating a self-oscillating term having a predetermined amplitude and a predetermined period, to thereby adjust said actual air-fuel ratio in accordance with said self-oscillating term.
Claim 8
Dependent Claim
56 words
A method as set forth in claim 6, further comprising the steps of: determining whether or not said engine is in an idling state; lowering said predetermined amplitude of said self-oscillating term when said engine is in said idling state; increasing said predetermined period of said self-oscillating term when said engine is in said idling state.
Claim 9
Independent Claim
212 words
An apparatus for controlling an air-fuel ratio in an internal combustion engine having a three-way catalyst converter for removing pollutants in the exhaust gas of said engine and an air-fuel ratio sensor disposed downstream of said three-way catalyst converter for detecting a specific component in the exhaust gas, said apparatus comprising: means for greatly changing a coarse-adjusting term when the output of said air-fuel ratio sensor is inverted from a rich state to a lean state and vice versa, and gradually changing said coarse-adjusting term when the output of said air-fuel ratio sensor remains in the same state; means for greatly changing a proportional amount of an O 2 storage adjusting term when the output of said air-fuel ratio sensor is under a first threshold value which is smaller than a value corresponding to the stoichiometric air-fuel ratio or over a second threshold value which is larger than a value corresponding to the stoichiometric air-fuel ratio; means for determining whether or not said catalyst converter is deteriorated; means for delaying an initiating timing of said O 2 storage term for a predetermined interval when said catalyst convertor is determined to be deteriorated; and, means for adjusting an actual air-fuel ratio in accordance with said coarse-adjusting term and said O 2 storage term.
Claim 10
Independent Claim
212 words
An apparatus for controlling an air-fuel ratio in an internal combustion engine having a three-way catalyst converter for removing pollutants in the exhaust gas of said engine and an air-fuel ratio sensor disposed downstream of said three-way catalyst converter for detecting a specific component in the exhaust gas, said apparatus comprising: means for greatly changing a coarse-adjusting term when the output of said air-fuel ratio sensor is inverted from a rich state to a lean state and vice versa, and gradually changing said coarse-adjusting term when the output of said air-fuel ratio sensor remains in the same state; means for greatly changing a proportional amount of an O 2 storage adjusting term when the output of said air-fuel ratio sensor is under a first threshold value which is smaller than a value corresponding to the stoichiometric air-fuel ratio or over a second threshold value which is larger than a value corresponding to the stoichiometric air-fuel ratio; means for determining whether or not said catalyst converter is deteriorated; means for delaying an initiating timing of said O 2 storage term for a predetermined interval when said catalyst convertor is determined to be deteriorated; and, means for adjusting an actual air-fuel ratio in accordance with said coarse-adjusting term and said O 2 storage term.
Claim 11
Dependent Claim
25 words
An apparatus as set forth in claim 8, wherein said initiating timing is varied in accordance with a degree of deterioration of said catalyst converter.
Claim 12
Dependent Claim
19 words
An apparatus as set forth in claim 8, further comprising means for gradually changing said O 2 storage term.
Claim 13
Dependent Claim
75 words
An apparatus as set forth in claim 8, wherein means for said catalyst converter deterioration determining comprises: means for determining whether or not an inverting interval, which is an interval form a time at which the output of the said air-fuel ratio sensor is inverted from the rich state to the lean state or vice versa to a time at which it is again inverted in the same direction, is shorter than a predetermined value.
Claim 14
Dependent Claim
39 words
An apparatus as set forth in claim 8, wherein means for said catalyst converter deterioration determining comprises: means for determining whether or not an amplitude of said output of said air-fuel ratio sensor is larger than a predetermined value.
Claim 15
Dependent Claim
37 words
An apparatus as set forth in claim 8, further comprising means for generating a self-oscillating term having a predetermined amplitude and a predetermined period, to thereby adjust said actual air-fuel ratio in accordance with said self-oscillating term.
Claim 16
Dependent Claim
59 words
An apparatus as set forth in claim 13, further comprising: means for determining whether or not said engine is in an idling state; means for lowering said predetermined amplitude of said self-oscillating term when said engine is in said idling state; means for increasing said predetermined period of said self-oscillating term when said engine is in said idling state.
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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) | 1995-03-31 | 1995-09-30 | 1996-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-31 | 1999-09-30 | 2000-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-31 | 2003-09-30 | 2004-03-31 | $7700.00 | Window Closed / Lapsed |