US5848527A
Expired / Lapsed
US
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Apparatus for detecting deterioration of a three-way catalytic converter for an engine
Assignee: Toyota Motor Corp
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Filing: 1997-03-26
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Granted: 1998-12-15
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Expires: 2017-03-26
Abstract
Abstract The object of the present invention is to provide an apparatus for detecting the deterioration of a converter enabled to avoid a misjudgement even though the balance between the oxygen absorbing power and the oxygen releasing power disappears. The present apparatus is furnished with an upstream air-fuel ratio sensor installed at the upstream side of the converter and a downstream air-fuel ratio sensor installed at the downstream side of the converter. The deterioration of the converter is detected in accordance with the trajectory lengths of these sensors, and a parameter which denotes the oxygen balance of the converter is calculated in accordance with the outputs of these sensors. When the value of the parameter is outside a fixed lower limit or a fixed upper limit, the detection for deterioration is inhibited in order to prevent a misjudgement occuring.
Inventors
- 👤 Noritake Mitsutani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:27
CPC Classifications
F; F01; F01N; F01N11/00; F01N11/007; F01N2550/00; F01N2550/02; F01N2900/00; F01N2900/04; F01N2900/0422; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
206 words
An apparatus for detecting deterioration of a three-way catalytic converter disposed in an exhaust passage of an internal combustion engine comprising: an upstream air-fuel ratio sensor disposed in the exhaust passage at the upstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the upstream side of said catalytic converter; a downstream air-fuel ratio sensor disposed in the exhaust passage at the downstream side of the converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the downstream side of the converter; an air-fuel ratio feedback control means for controlling the amount of fuel supplied to the engine at least in accordance with the output of said upstream air-fuel ratio sensor; a deterioration detecting means for detecting a deterioration of the converter at least in accordance with the output of said downstream air-fuel ratio sensor; an oxygen balance estimating means for estimating a balance between the oxygen absorbing power and the oxygen releasing power; and a detection inhibiting means for inhibiting the detection of the deterioration in accordance with said deterioration detecting means when the oxygen balance estimated by said oxygen balance estimating means deviates from at least one fixed threshold.
Claim 2
Independent Claim
206 words
An apparatus for detecting deterioration of a three-way catalytic converter disposed in an exhaust passage of an internal combustion engine comprising: an upstream air-fuel ratio sensor disposed in the exhaust passage at the upstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the upstream side of said catalytic converter; a downstream air-fuel ratio sensor disposed in the exhaust passage at the downstream side of the converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the downstream side of the converter; an air-fuel ratio feedback control means for controlling the amount of fuel supplied to the engine at least in accordance with the output of said upstream air-fuel ratio sensor; a deterioration detecting means for detecting a deterioration of the converter at least in accordance with the output of said downstream air-fuel ratio sensor; an oxygen balance estimating means for estimating a balance between the oxygen absorbing power and the oxygen releasing power; and a detection inhibiting means for inhibiting the detection of the deterioration in accordance with said deterioration detecting means when the oxygen balance estimated by said oxygen balance estimating means deviates from at least one fixed threshold.
Claim 3
Dependent Claim
141 words
An apparatus for detecting deterioration of a converter for an engine of claim 1, wherein said oxygen balance estimating means comprises: a fuel difference calculating means for calculating a difference between the target amount of fuel required to maintain the air-fuel ratio of the engine at the stoichiometric air-fuel ratio and the actual amount of fuel supplied to the engine calculated in said air-fuel ratio feedback control means; a change detecting means for detecting the change of the output of said downstream air-fuel ratio sensor; and a fuel difference integrating means for integrating a fuel difference calculated by said fuel difference calculating means to estimate the oxygen balance from the time when said change detecting means detects the first change of the output of said downstream air-fuel ratio sensor to the time when said change detecting means detects the second change.
Claim 4
Dependent Claim
73 words
An apparatus for detecting deterioration of a catalytic converter for an engine of claim 2, wherein said detection inhibiting means restrains from inhibiting the detection until a fixed interval is elapsed after the change of the output of said downstream air-fuel ratio sensor is detected by said change detecting means though the fuel difference integral integrated by said fuel difference integrating means deviates from a fixed upper limit or a fixed lower limit.
Claim 5
Dependent Claim
56 words
An apparatus for detecting deterioration of a catalytic converter for an engine of claim 2, wherein said change detecting means has a hysteresis characteristic between a threshold used for detecting a change from the rich state to the lean state and a threshold used for detecting a change from the lean state to the rich state.
Claim 6
Dependent Claim
60 words
An apparatus for detecting deterioration of a catalytic converter for an engine of claim 1, wherein said deterioration detecting means detects the deterioration of the converter in accordance with the length of the response curve of the output of said upstream air-fuel ratio sensor and the length of the response curve of the output of said downstream air-fuel ratio sensor.
Claim 7
Dependent Claim
55 words
An apparatus for detecting deterioration of a catalytic converter for an engine of claim 2, wherein said deterioration detecting means detects the deterioration of the converter in accordance with the frequency of deviations of the fuel difference integral integrated by said fuel difference integrating means from a fixed upper limit or a fixed lower limit.
Claim 8
Independent Claim
255 words
An apparatus for detecting deterioration of a catalytic converter disposed in an exhaust passage of an internal combustion engine comprising: an upstream air-fuel ratio sensor disposed in the exhaust passage at the upstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the upstream side of said catalytic converter; a downstream air-fuel ratio sensor disposed in the exhaust passage at the downstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the downstream side of said catalytic converter; an air-fuel ratio feedback control means for calculating an air-fuel ratio correction factor for correcting the amount of fuel supplied to the engine at least in accordance with said upstream air-fuel ratio sensor and an air-fuel ratio leaning factor for compensating for age deterioration of devices related to a fuel supply system; a deterioration detecting means for detecting a deterioration of the converter at least in accordance with the output of said downstream air-fuel ratio sensor; an oxygen balance estimating means for estimating a balance between the oxygen absorbing power and the oxygen releasing power in accordance with the integral of the difference between the air-fuel ratio correction factor and the air-fuel ratio leaning factor calculated by said air-fuel ratio feedback control means; and a detection inhibiting means for inhibiting the detection of the deterioration with said deterioration detecting means when the balance estimated by said oxygen balance estimating means deviates from at least one fixed threshold.
Claim 9
Independent Claim
255 words
An apparatus for detecting deterioration of a catalytic converter disposed in an exhaust passage of an internal combustion engine comprising: an upstream air-fuel ratio sensor disposed in the exhaust passage at the upstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the upstream side of said catalytic converter; a downstream air-fuel ratio sensor disposed in the exhaust passage at the downstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the downstream side of said catalytic converter; an air-fuel ratio feedback control means for calculating an air-fuel ratio correction factor for correcting the amount of fuel supplied to the engine at least in accordance with said upstream air-fuel ratio sensor and an air-fuel ratio leaning factor for compensating for age deterioration of devices related to a fuel supply system; a deterioration detecting means for detecting a deterioration of the converter at least in accordance with the output of said downstream air-fuel ratio sensor; an oxygen balance estimating means for estimating a balance between the oxygen absorbing power and the oxygen releasing power in accordance with the integral of the difference between the air-fuel ratio correction factor and the air-fuel ratio leaning factor calculated by said air-fuel ratio feedback control means; and a detection inhibiting means for inhibiting the detection of the deterioration with said deterioration detecting means when the balance estimated by said oxygen balance estimating means deviates from at least one fixed threshold.
Claim 10
Independent Claim
210 words
A method for detecting deterioration of a three-way catalytic converter disposed in an exhaust passage of an internal combustion engine with an upstream air-fuel ratio sensor disposed in the exhaust passage at the upstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the upstream side of said catalytic converter and a downstream air-fuel ratio sensor disposed in the exhaust passage at the downstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the downstream side of said catalytic converter comprising the steps of; an air-fuel ratio feedback control step for controlling the amount of fuel supplied to the engine at least in accordance with the output of the upstream air-fuel ratio sensor; a deterioration detecting step for detecting deterioration of the converter at least in accordance with the output of the downstream air-fuel ratio sensor; an oxygen balance estimating step for estimating a balance between the oxygen absorbing power and the oxygen releasing power; and a detection inhibiting step for inhibiting the detection of the deterioration degree at said deterioration detecting step when the balance estimated at said oxygen balance estimating step deviates from at least one fixed threshold.
Claim 11
Independent Claim
210 words
A method for detecting deterioration of a three-way catalytic converter disposed in an exhaust passage of an internal combustion engine with an upstream air-fuel ratio sensor disposed in the exhaust passage at the upstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the upstream side of said catalytic converter and a downstream air-fuel ratio sensor disposed in the exhaust passage at the downstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the downstream side of said catalytic converter comprising the steps of; an air-fuel ratio feedback control step for controlling the amount of fuel supplied to the engine at least in accordance with the output of the upstream air-fuel ratio sensor; a deterioration detecting step for detecting deterioration of the converter at least in accordance with the output of the downstream air-fuel ratio sensor; an oxygen balance estimating step for estimating a balance between the oxygen absorbing power and the oxygen releasing power; and a detection inhibiting step for inhibiting the detection of the deterioration degree at said deterioration detecting step when the balance estimated at said oxygen balance estimating step deviates from at least one fixed threshold.
Claim 12
Dependent Claim
144 words
A method for detecting deterioration of a catalytic converter for an engine of claim 8, wherein said oxygen balance estimating step comprises steps of: a fuel difference calculating step for calculating a difference between a target amount of fuel required to maintain the air-fuel ratio of the engine at the stoichiometric air-fuel ratio and an actual amount of fuel calculated at said air-fuel ratio feedback control step; a change detecting step for detecting the change of the output of the downstream air-fuel ratio sensor; and a fuel difference integrating step for integrating a fuel difference calculated at said fuel difference calculating step to estimate the oxygen balance form the time when the first change of the output of said downstream air-fuel ratio sensor is detected at said change detecting step to the time when the second change is detected at said change detecting step.
Claim 13
Dependent Claim
73 words
A method for detecting deterioration of a catalytic converter for an engine of claim 9, wherein said detection inhibiting step restrains from inhibiting the detection until a fixed interval is elapsed after the change of the output of said downstream air-fuel ratio sensor is detected at said change detecting step though the fuel difference integral integrated at said fuel difference integrating step deviates from a fixed upper limit or a fixed lower limit.
Claim 14
Dependent Claim
54 words
A method for detecting deterioration of a catalytic converter for an engine of claim 9, wherein said change detecting step has a hysteresis characteristic between a threshold used for a change from the rich state to the lean state and a threshold used for a change from the lean state to the rich state.
Claim 15
Dependent Claim
59 words
A method for detecting deterioration of a converter for an engine of claim 8, wherein said deterioration detecting step detects the deterioration of the converter in accordance with the length of the response curve of the output of the upstream air-fuel ratio sensor and the length of the response curve of the output of the downstream air-fuel ratio sensor.
Claim 16
Dependent Claim
54 words
A method for detecting deterioration of a converter for an engine of claim 9, wherein said deterioration detecting step detects the deterioration of the converter in accordance with the frequency of deviations of the fuel difference integral integrated at said fuel difference integrating step from a fixed upper limit or a fixed lower limit.
Claim 17
Independent Claim
256 words
A method for detecting deterioration of a three-way catalytic converter disposed in an exhaust passage of an internal combustion engine with an upstream air-fuel ratio sensor disposed in the exhaust passage at the upstream side of said catalytic converter for outputting a signal substantially proportional to the air-fuel ratio of the exhaust gas at the upstream side of said catalytic converter and a downstream air-fuel ratio sensor disposed in the exhaust passage at the downstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the downstream side of said catalytic converter comprising the steps of; an air-fuel ratio feedback control step for calculating an air-fuel ratio correction factor for correcting the amount of fuel supplied to the engine at least in accordance with the output of the upstream air-fuel ratio sensor and an air-fuel ratio leaning factor for compensating for age deterioration of devices related to a fuel supply system; a deterioration detecting step for detecting a deterioration degree of the converter at least in accordance with the output of the downstream air-fuel ratio sensor; an oxygen balance estimating step for estimating a balance in accordance with the integral of the difference between the air-fuel ratio correction factor and the air-fuel ratio leaning factor calculated at said air-fuel ratio feedback control step; and a detection inhibiting step for inhibiting the detection of the deterioration at said deterioration detecting step when the balance estimated at said oxygen balance estimating step deviates from at least one fixed threshold.
Claim 18
Independent Claim
256 words
A method for detecting deterioration of a three-way catalytic converter disposed in an exhaust passage of an internal combustion engine with an upstream air-fuel ratio sensor disposed in the exhaust passage at the upstream side of said catalytic converter for outputting a signal substantially proportional to the air-fuel ratio of the exhaust gas at the upstream side of said catalytic converter and a downstream air-fuel ratio sensor disposed in the exhaust passage at the downstream side of said catalytic converter for outputting a signal corresponding to the air-fuel ratio of the exhaust gas at the downstream side of said catalytic converter comprising the steps of; an air-fuel ratio feedback control step for calculating an air-fuel ratio correction factor for correcting the amount of fuel supplied to the engine at least in accordance with the output of the upstream air-fuel ratio sensor and an air-fuel ratio leaning factor for compensating for age deterioration of devices related to a fuel supply system; a deterioration detecting step for detecting a deterioration degree of the converter at least in accordance with the output of the downstream air-fuel ratio sensor; an oxygen balance estimating step for estimating a balance in accordance with the integral of the difference between the air-fuel ratio correction factor and the air-fuel ratio leaning factor calculated at said air-fuel ratio feedback control step; and a detection inhibiting step for inhibiting the detection of the deterioration at said deterioration detecting step when the balance estimated at said oxygen balance estimating step deviates from at least one fixed threshold.
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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) | 2001-12-14 | 2002-06-15 | 2002-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-14 | 2006-06-15 | 2006-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-14 | 2010-06-15 | 2010-12-15 | $7700.00 | Window Closed / Lapsed |