Patent US4748953A successfully refreshed from Google Patents.
US4748953A
Expired / Lapsed
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Air/fuel ratio control apparatus for internal combustion engines
Assignee: Hitachi Ltd
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Filing: 1986-11-20
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Granted: 1988-06-07
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Expires: 2006-11-20
Abstract
Abstract In feedback control for the air/fuel ratio based on a sensor producing an output signal proportional to a change in the air/fuel ratio, a control constant modifier is operative to vary the proportional component and the integration component in a feedback system in accordance with an air/fuel ratio set for controlling, thereby assuring stability of ultimate fuel control.
Inventors
- 👤 Minoru Osuga
- 👤 Yoshishige Oyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:08
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1477; F02D41/1483; F02D41/1479; F02D41/1444; F02D41/1454; F02D41/1456
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
113 words
An air/fuel ratio control apparatus for an internal combustion engine comprising: air/fuel ratio sensor means for detecting an amount of oxygen or combustible component remaining in an exhaust gas to produce an output signal having a value which is proportional to an air/fuel ratio in said engine; means responsive to the output signal from said air/fuel ratio sensor means for controlling by closed loop control the air/fuel ratio of a mixture of gas and air fed to said engine on the basis of predetermined air/fuel ratio control constants; and means for varying said air/fuel ratio control constants used for said closed loop control in accordance with a selected control value of air/fuel ratio.
Claim 2
Dependent Claim
113 words
An air/fuel ratio control apparatus for an internal combustion engine comprising: air/fuel ratio sensor means for detecting an amount of oxygen or combustible component remaining in an exhaust gas to produce an output signal having a value which is proportional to an air/fuel ratio in said engine; means responsive to the output signal from said air/fuel ratio sensor means for controlling by closed loop control the air/fuel ratio of a mixture of gas and air fed to said engine on the basis of predetermined air/fuel ratio control constants; and means for varying said air/fuel ratio control constants used for said closed loop control in accordance with a selected control value of air/fuel ratio.
Claim 3
Dependent Claim
43 words
An air/fuel ratio control apparatus according to claim 1 wherein said air/fuel ratio control constants include an integration constant and a proportional constant, and at least one of the two constants are varied in accordance with said selected control value of air/fuel ratio.
Claim 4
Dependent Claim
50 words
An air/fuel ratio control apparatus according to claim 2 wherein the proportional and integration constants for a first region where the air/fuel ratio is larger than the stoichiometric air/fuel ratio is made different from those for a second region where the air/fuel ratio is smaller than the stoichiometric air/fuel ratio.
Claim 5
Dependent Claim
28 words
An air/fuel ratio control apparatus according to claim 3 wherein the proportional and integration constants are varied continuously in accordance with said selected control value of air/fuel ratio.
Claim 6
Dependent Claim
28 words
An air/fuel ratio control apparatus according to claim 3 wherein the proportional and integration constants for said first region are made larger than those for said second region.
Claim 7
Dependent Claim
112 words
An air/fuel ratio control apparatus for an internal combustion engine using air/fuel ratio sensor means for detecting an amount of oxygen or combustible component remaining in an exhaust gas to produce an output signal having a value which is proportional to an air/fuel ratio in said engine and performing closed loop control of the air/fuel ratio of a mixture gas and air fed to said engine on the basis of the output signal from said air/fuel ratio sensor and in accordance with predetermined air/fuel ratio control constants, including means for varying said air/fuel ratio control constants used for the closed loop control in accordance with a selected control value of air/fuel ratio.
Claim 8
Dependent Claim
112 words
An air/fuel ratio control apparatus for an internal combustion engine using air/fuel ratio sensor means for detecting an amount of oxygen or combustible component remaining in an exhaust gas to produce an output signal having a value which is proportional to an air/fuel ratio in said engine and performing closed loop control of the air/fuel ratio of a mixture gas and air fed to said engine on the basis of the output signal from said air/fuel ratio sensor and in accordance with predetermined air/fuel ratio control constants, including means for varying said air/fuel ratio control constants used for the closed loop control in accordance with a selected control value of air/fuel ratio.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-07 | 1991-12-07 | 1992-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-07 | 1995-12-07 | 1996-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-07 | 1999-12-07 | 2000-06-07 | $7700.00 | Window Closed / Lapsed |