US5964208A
Expired / Lapsed
US
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Abnormality diagnosing system for air/fuel ratio feedback control system
Assignee: Denso Corp
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Filing: 1997-06-18
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Granted: 1999-10-12
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Expires: 2017-06-18
Abstract
Abstract An air/fuel ratio control system controls the supply of fuel to an internal combustion engine to achieve a target air/fuel ratio, based on the output of an air/fuel ratio sensor. The system may determine whether there is an abnormality in the air/fuel ratio sensor based on a comparison between a change of an air/fuel ratio correction coefficient, used to drive the air/fuel ratio to the target value, and a change of the target air/fuel ratio if the target air/fuel ratio has sharply changed. Alternatively, the diagnosis operation may be performed based on a comparison between a total air/fuel ratio correction amount and a change of the air/fuel ratio detected by the air/fuel ratio sensor, a phase difference calculation between peaks of the air/fuel ratio or the air/fuel ratio correction coefficient, or by accumulating the differences between the air/fuel ratio and the target air/fuel ratio, and the differences between the air/fuel ratio correction coefficient and a reference value, and comparing the accumulated values. In addition, the system may detect a sensor abnormality based on the deviation in phase of the air/fuel ratio from the air/fuel ratio correction coefficient. These diagnosis operations can precisely and easily detect the occurrence of an abnormality in the air/fuel ratio sensor. As a result, the air/fuel ratio control system will not use an imprecise output from the sensor for air/fuel ratio control, thus achieving highly precise and highly reliable air/fuel ratio control.
Inventors
- 👤 Yukihiro Yamashita
- 👤 Jun Hasegawa
- 👤 Hisashi Iida
- 👤 Wakichi Kondo
- 👤 Yasuo Sagisaka
- 👤 Masahiko Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:56
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1493; F02D41/1495; F02D41/1444; F02D41/1454; F02D41/1456; F02D41/22; F02D41/1401; F02D2041/1413; F02D2041/1432; F02D41/1439; F02D41/1441; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
143 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; and sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, wherein the sensor diagnostic means is for checking for an abnormality of the air/fuel ratio sensor by comparing behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient.
Claim 2
Dependent Claim
143 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; and sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, wherein the sensor diagnostic means is for checking for an abnormality of the air/fuel ratio sensor by comparing behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient.
Claim 3
Dependent Claim
202 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, first amplitude calculating means for calculating an amplitude of the air/fuel ratio detected by the air/fuel ratio sensor; and second amplitude calculating means for calculating an amplitude of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; wherein the sensor diagnostic means is for checking for an abnormality of the air/fuel ratio sensor based on a comparison between the amplitude of the air/fuel ratio calculated by the first amplitude calculating means and the amplitude of the air/fuel ratio correction coefficient calculated by the second amplitude calculating means.
Claim 4
Dependent Claim
202 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, first amplitude calculating means for calculating an amplitude of the air/fuel ratio detected by the air/fuel ratio sensor; and second amplitude calculating means for calculating an amplitude of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; wherein the sensor diagnostic means is for checking for an abnormality of the air/fuel ratio sensor based on a comparison between the amplitude of the air/fuel ratio calculated by the first amplitude calculating means and the amplitude of the air/fuel ratio correction coefficient calculated by the second amplitude calculating means.
Claim 5
Dependent Claim
59 words
A controller accrding to claim 2, further comprising: air/fuel ratio period calculating means for calculating an oscillation period of the air/fuel ratio detected by the air/fuel ratio sensor; wherein the sensor diagnostic means further includeds means for checking for an abnormality of the air/fuel ratio sensor based on the oscillation period detected by the air/fuel ratio period calculating means.
Claim 6
Dependent Claim
64 words
A controller according to claim 2, further comprising: correction coefficient period calculating means for calculating an oscillation period of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; wherein the sensor diagnostic means further includes means for checking for an abnormality of the air/fuel ratio sensor based on the oscillation period detected by the correction coefficient period calculating means.
Claim 7
Dependent Claim
177 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set bv the air/fuel ratio correction coefficient generating means; sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, phase difference calculating means for calculating a phase difference between a phase of the air/fuel ratio detected by the air/fuel ratio sensor and a phase of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; wherein the sensor diagnostic means is for checking for abnormality of the air/fuel ratio sensor based on the phase difference calculated by the phase difference calculating means.
Claim 8
Dependent Claim
177 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set bv the air/fuel ratio correction coefficient generating means; sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, phase difference calculating means for calculating a phase difference between a phase of the air/fuel ratio detected by the air/fuel ratio sensor and a phase of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; wherein the sensor diagnostic means is for checking for abnormality of the air/fuel ratio sensor based on the phase difference calculated by the phase difference calculating means.
Claim 9
Dependent Claim
64 words
A controller according to claim 5, wherein the phase difference calculating means is for calculating a phase difference by detecting a period between a time when one of the air/fuel ratio and the air/fuel ratio correction coefficient indicates a stoichiometric air/fuel ratio and a time when the other one of the air/fuel ratio and the air/fuel ratio correction coefficient indicates the stoichiometric air/fuel ratio.
Claim 10
Dependent Claim
62 words
A controller according to claim 5, wherein the phase difference calculating means is for calculating a phase difference by detecting a period between a time when one of the air/fuel ratio and the air/fuel ratio correction coefficient indicates a peak value and a time when the other one of the air/fuel ratio and the air/fuel ratio correction coefficient indicates a peak value.
Claim 11
Dependent Claim
58 words
A controller according to claim 5, wherein the phase difference calculating means includes means for detecting the phase difference based on whether when one of the air/fuel ratio and the air/fuel ratio correction coefficient indicates a stoichiometric air/fuel ratio, and the other one of the air/fuel ratio and the air/fuel ratio correction coefficient indicates the stoichiometric air/fuel ratio.
Claim 12
Dependent Claim
59 words
A controller according to claim 5, further comprising: air/fuel ratio period calculating means for calculating an oscillation period of the air/fuel ratio detected by the air/fuel ratio sensor; wherein the sensor diagnostic means further includes means for checking for an abnormality of the air/fuel ratio sensor based on the oscillation period detected by the air/fuel ratio period calculating means.
Claim 13
Dependent Claim
64 words
A controller according to claim 5, further comprising: correction coefficient period calculating means for calculating an oscillation period of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; wherein the sensor diagnostic means further includes means for checking for an abnormality of the air/fuel ratio sensor based on the oscillation period detected by the correction coefficient period calculating means.
Claim 14
Dependent Claim
202 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set bv the air/fuel ratio correction coefficient generating means; sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, first difference accumulating means for accumulating differences between the air/fuel ratio detected by the air/fuel ratio sensor and the target air/fuel ratio; and second difference accumulating means for accumulating differences between the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means and a reference value of the air/fuel ratio correction coefficient; wherein the sensor diagnostic means is for checking for an abnormality of the air/fuel ratio sensor based on comparison between differences accumulated by the first difference accumulating means and differences accumulated by the second difference accumulating means.
Claim 15
Dependent Claim
202 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set bv the air/fuel ratio correction coefficient generating means; sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, first difference accumulating means for accumulating differences between the air/fuel ratio detected by the air/fuel ratio sensor and the target air/fuel ratio; and second difference accumulating means for accumulating differences between the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means and a reference value of the air/fuel ratio correction coefficient; wherein the sensor diagnostic means is for checking for an abnormality of the air/fuel ratio sensor based on comparison between differences accumulated by the first difference accumulating means and differences accumulated by the second difference accumulating means.
Claim 16
Dependent Claim
173 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set bv the air/fuel ratio correction coefficient generating means; sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, air/fuel ratio change calculating means for calculating a change rate of the detected air/fuel ratio; and correction coefficient change calculating means for calculating a change rate of the air/fuel ratio correction coefficient; wherein the sensor diagnostic means includes abnormality diagnosing means for diagnosing an abnormality of the air/fuel ratio sensor based on the air/fuel ratio change rate and the correction coefficient change rate.
Claim 17
Dependent Claim
173 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set bv the air/fuel ratio correction coefficient generating means; sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, air/fuel ratio change calculating means for calculating a change rate of the detected air/fuel ratio; and correction coefficient change calculating means for calculating a change rate of the air/fuel ratio correction coefficient; wherein the sensor diagnostic means includes abnormality diagnosing means for diagnosing an abnormality of the air/fuel ratio sensor based on the air/fuel ratio change rate and the correction coefficient change rate.
Claim 18
Dependent Claim
32 words
A controller according to claim 12, wherein the air/fuel ratio change calculating means is for determining the change rate of the air/fuel ratio based on a second derivative of the air/fuel ratio.
Claim 19
Dependent Claim
34 words
A controller according to claim 12, wherein the correction coefficient change calculating means is for determining the change rate of the air/fuel ratio correction coefficient based on a second derivative of the correction coefficient.
Claim 20
Dependent Claim
62 words
A controller according to claim 12, wherein: the air/fuel ratio change calculating means is for calculating the change rate of the air/fuel ratio based on an amplitude of the air/fuel ratio change rate; and the correction coefficient change calculating means is for calculating the change rate of the air/fuel ratio correction coefficient based on an amplitude of the correction coefficient change rate.
Claim 21
Dependent Claim
121 words
A controller according to claim 12, wherein: the air/fuel ratio change calculating means includes means for accumulating a second derivative of the air/fuel ratio for a predetermined time period to determine the accumulated value as the air/fuel ratio change rate; the correction coefficient change calculating means includes means for accumulating the second derivative of the air/fuel ratio correction coefficient for a predetermined time period to determine the accumulated value as the correction coefficient change rate; and the abnormality diagnosing means includes means for comparing a ratio between the accumulated second derivative of the air/fuel ratio and the accumulated second derivative of the air/fuel ratio correction coefficient with a predetermined abnormality deciding value to diagnose an abnormality of the air/fuel ratio sensor.
Claim 22
Dependent Claim
121 words
A controller according to claim 12, wherein: the air/fuel ratio change calculating means includes means for accumulating the amplitude of the air/fuel ratio change for a predetermined time period to determine the accumulated value as the air/fuel ratio change rate; the correction coefficient change calculating means includes means for accumulating the amplitude of the air/fuel ratio correction coefficient change for a predetermined time period to determine the accumulated value as the correction coefficient change rate; and the abnormality diagnosing means includes means for comparing a ratio between the accumulated amplitude of the air/fuel ratio change and the accumulated amplitude of the air/fuel ratio correction coefficient change with a predetermined abnormality deciding value to diagnose an abnormality of the air/fuel ratio sensor.
Claim 23
Dependent Claim
25 words
A controller according to claim 12, further comprising abnormality deciding value generating means for determining the abnormality deciding value variably with an engine running state.
Claim 24
Dependent Claim
48 words
A controller according to claim 12, wherein the abnormality diagnosing means is for diagnosing that the sensor is normal when the ratio between the change rate of the air/fuel ratio and the change rate of the air/fuel ratio correction coefficient is less than a predetermined abnormality deciding value.
Claim 25
Dependent Claim
56 words
A controller according to claim 12, wherein the abnormality diagnosing means is for diagnosing that the sensor is normal when the ratio between the change rate of the air/fuel ratio and the change rate of the air/fuel ratio correction coefficient is greater than a first abnormality deciding value and less than a second abnormality deciding value.
Claim 26
Dependent Claim
76 words
A controller according to claim 12, wherein: the air/fuel ratio change calculating means is for calculating the change rate of the air/fuel ratio by smoothing the air/fuel ratio and using the smoothed air/fuel ratio λSM to calculate the air/fuel change ratio; and the correction coefficient change calculating means is for calculating the change rate of the correction coefficient by smoothing the correction coefficient and using the smoothed correction coefficient to calculate the correction coefficient change ratio.
Claim 27
Dependent Claim
198 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, first element calculating means for calculating a first abnormality deciding element based on the detected air/fuel ratio; and second element calculating means for calculating a second abnormality deciding element based on the air/fuel ratio correction coefficient; wherein the sensor diagnostic means includes abnormalilty diagnosing means for diagnosing an abnormality of the air/fuel ratio feedback control system in accordance with a plurality of normality/abnormality deciding regions, as individually defined by at least one threshold value, by correlating the first and second abnormality deciding elements with the normality/abnormality deciding regions.
Claim 28
Dependent Claim
198 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor for generating a signal representative of a detected air/fuel ratio of an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient according to a difference between the detected air/fuel ratio and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine using the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; sensor diagnostic means for checking an abnormality of the air/fuel ratio sensor based on behavior of the detected air/fuel ratio and behavior of the air/fuel ratio correction coefficient, first element calculating means for calculating a first abnormality deciding element based on the detected air/fuel ratio; and second element calculating means for calculating a second abnormality deciding element based on the air/fuel ratio correction coefficient; wherein the sensor diagnostic means includes abnormalilty diagnosing means for diagnosing an abnormality of the air/fuel ratio feedback control system in accordance with a plurality of normality/abnormality deciding regions, as individually defined by at least one threshold value, by correlating the first and second abnormality deciding elements with the normality/abnormality deciding regions.
Claim 29
Dependent Claim
73 words
A controller according to claim 22, wherein: the first element calculating means is for calculating the first abnormality deciding element as the difference between the detected air/fuel ratio and the target air/fuel ratio; and the second element calculating means is for calculating as the second abnormality deciding element the difference between the air/fuel ratio correction coefficient determined by the air/fuel ratio correction coefficient determining means and an average value of the correction coefficient.
Claim 30
Dependent Claim
77 words
A controller according to claim 22, wherein: the first element calculating means is for calculating the first abnormality deciding element by sequentially accumulating the difference between the detected air/fuel ratio and the target air/fuel ratio; and the second element calculating means is for calculating the second abnormality deciding element by sequentially accumulating the difference between the air/fuel ratio correction coefficient determined by the air/fuel ratio correction coefficient determining means and the average value of the correction coefficient.
Claim 31
Dependent Claim
50 words
A controller according to claim 22, wherein the abnormality diagnosing means is for diagnosing that the air/fuel ratio feedback control system is abnoral if the first and second abnormality deciding elements belong to the abnormality deciding regions by a predetermined number or more within a preset number of abnormality decisions.
Claim 32
Dependent Claim
61 words
A controller according to claim 22, wherein the abnormality diagnosing means is for inhibiting the regions in which the fluctuations of the air/fuel ratio with respect to the target air/fuel ratio and the air/fuel ratio correction coefficient with respect to its average value are less than predetermined values from deciding whether or not the air/fuel ratio feedback control system is normal.
Claim 33
Dependent Claim
49 words
A controller according to claim 22, wherein a plurality of normality/abnormality deciding regions corresponding to the first and second abnormality deciding elements are stored and held as an equation in memory so that the abnormality diagnosing means executes the abnormality diagnosis with the normality/abnormality deciding regions of the equation.
Claim 34
Dependent Claim
47 words
A controller according to claim 27, wherein the equation includes a multiplicity of regions which are equally divided into a plurality of groups according to the first and second abnormality deciding elements and individually stored with at least one of data of normality and data of abnormality.
Claim 35
Dependent Claim
31 words
A controller according to claim 22, further comprising decision region learning means for learning normality/abnormality deciding regions corresponding to the first and second abnormality deciding elements based on predetermined learning conditions.
Claim 36
Dependent Claim
68 words
A controller according to claim 29, wherein the decision region learning means is for learning the normality/abnormality deciding regions to enlarge a normality deciding region relating to the air/fuel ratio correction coefficient if an abnormality is detected based on the first abnormality deciding element, and to enlarge the normality deciding region relating to the air/fuel ratio if an abnormality is detected based on the second abnormality deciding element.
Claim 37
Dependent Claim
132 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor which can vary its output linearly when detecting an air/fuel ratio in an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient in accordance with a difference between the air/fuel ratio detected by the air/fuel ratio sensor and a target air/fuel ratio; air/fuel ratio control means for controlling amount of fuel to be supplied to the engine by using the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; air/fuel ratio period calculating means for calculating an oscillation period of the air/fuel ratio detected by the air/fuel ratio sensor; and sensor diagnostic means for checking for an abnormality of the air/fuel ratio sensor based on the oscillation period of the air/fuel ratio.
Claim 38
Dependent Claim
132 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor which can vary its output linearly when detecting an air/fuel ratio in an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient in accordance with a difference between the air/fuel ratio detected by the air/fuel ratio sensor and a target air/fuel ratio; air/fuel ratio control means for controlling amount of fuel to be supplied to the engine by using the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; air/fuel ratio period calculating means for calculating an oscillation period of the air/fuel ratio detected by the air/fuel ratio sensor; and sensor diagnostic means for checking for an abnormality of the air/fuel ratio sensor based on the oscillation period of the air/fuel ratio.
Claim 39
Dependent Claim
166 words
A controller according to claim 31, further comprising: first amplitude calculating means for calculating an amplitude of the air/fuel ratio detected by the air/fuel ratio sensor; second amplitude calculating means for calculating an amplitude of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; and phase difference calculating means for calculating a phase difference between a phase of the air/fuel ratio detected by the air/fuel ratio sensor and a phase of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; wherein the sensor diagnostic means further includes means for checking for an abnormality of the air/fuel ratio sensor based on a comparison between the amplitude of the air/fuel ratio calculated by the first amplitude calculating means and the amplitude of the air/fuel ratio correction coefficient calculated by the second amplitude calculating means, and means for checking for an abnormality of the air/fuel ratio sensor based on the phase difference calculated by the phase difference calculating means.
Claim 40
Dependent Claim
140 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor which can vary its output linearly when detecting an air/fuel ratio in an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient in accordance with a difference between the air/fuel ratio detected by the air/fuel ratio sensor and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine by using the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; correction coefficient period calculating means for calculating an oscillation period of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; and sensor diagnostic means for checking for an abnormality of the air/fuel ratio sensor based on the oscillation period of the air/fuel ratio correction coefficient.
Claim 41
Dependent Claim
140 words
An air/fuel ratio controller comprising: an air/fuel ratio sensor which can vary its output linearly when detecting an air/fuel ratio in an internal combustion engine; air/fuel ratio correction coefficient generating means for generating an air/fuel ratio correction coefficient in accordance with a difference between the air/fuel ratio detected by the air/fuel ratio sensor and a target air/fuel ratio; air/fuel ratio control means for controlling an amount of fuel to be supplied to the engine by using the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; correction coefficient period calculating means for calculating an oscillation period of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; and sensor diagnostic means for checking for an abnormality of the air/fuel ratio sensor based on the oscillation period of the air/fuel ratio correction coefficient.
Claim 42
Dependent Claim
166 words
A controller according to claim 33, further comprising: first amplitude calculating means for calculating an amplitude of the air/fuel ratio detected by the air/fuel ratio sensor; second amplitude calculating means for calculating an amplitude of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; and phase difference calculating means for calculating a phase difference between a phase of the air/fuel ratio detected by the air/fuel ratio sensor and a phase of the air/fuel ratio correction coefficient set by the air/fuel ratio correction coefficient generating means; wherein the sensor diagnostic means further includes means for checking for an abnormality of the air/fuel ratio sensor based on a comparison between the amplitude of the air/fuel ratio calculated by the first amplitude calculating means and the amplitude of the air/fuel ratio correction coefficient calculated by the second amplitude calculating means, and means for checking for an abnormality of the air/fuel ratio sensor based on the phase difference calculated by the phase difference calculating means.
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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) | 2002-10-11 | 2003-04-12 | 2003-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-10-11 | 2007-04-12 | 2007-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-10-11 | 2011-04-12 | 2011-10-12 | $7700.00 | Window Closed / Lapsed |