US4853862A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for controlling air-fuel ratio in an internal combustion engine by corrective feedback control
Assignee: Hitachi Ltd
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Filing: 1986-01-22
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Granted: 1989-08-01
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Expires: 2006-01-22
Abstract
Abstract A method of controlling air-fuel ratio in which addition or subtraction is carried out on the basis of the output of an exhaust gas sensor to determine a feedback constant by which the air-fuel ratio is feedback-controlled. The feedback constant is changed at a given regular interval.
Inventors
- 👤 Takashi Shiraishi
- 👤 Taiji Hasegawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:16
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1477; F02D41/1483
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
144 words
An air-fuel ratio control system for an engine comprising: exhaust gas sensor means for detecting a state of exhaust gas so as to produce an output signal indicating a state of an air-fuel ratio of the engine; a processor unit for calculating a control value on the basis of the state of the exhaust gas by: (a) comparing said output signal of said exhaust gas sensor with a predetermined value so as to produce a comparison result; (b) generating in response to said comparison result a control signal having a first proportional correction component at a first period and a predetermined integral slope; and (c) correcting said control signal by periodically adding a second proportional correction component thereto at a second period which is longer than said first period; and means for controlling said air-fuel ratio on the basis of said corrected control signal.
Claim 2
Dependent Claim
144 words
An air-fuel ratio control system for an engine comprising: exhaust gas sensor means for detecting a state of exhaust gas so as to produce an output signal indicating a state of an air-fuel ratio of the engine; a processor unit for calculating a control value on the basis of the state of the exhaust gas by: (a) comparing said output signal of said exhaust gas sensor with a predetermined value so as to produce a comparison result; (b) generating in response to said comparison result a control signal having a first proportional correction component at a first period and a predetermined integral slope; and (c) correcting said control signal by periodically adding a second proportional correction component thereto at a second period which is longer than said first period; and means for controlling said air-fuel ratio on the basis of said corrected control signal.
Claim 3
Dependent Claim
24 words
A system according to claim 1, wherein said first period is of a fixed predetermined length and said second period varies with engine speed.
Claim 4
Dependent Claim
20 words
A system according to claim 1, wherein said further proportional correction component has a value which varies with engine speed.
Claim 5
Dependent Claim
20 words
A system according to claim 1, wherein said further proportional correction component has a value which varies with engine load.
Claim 6
Dependent Claim
48 words
A system according to claim 1, wherein said processor unit operates to add said second proportional correction component at a selected interval which is not related to the timing of the output of said exhaust gas sensor, while maintaining the value of said predetermined integral slope without change.
Claim 7
Independent Claim
146 words
A method of controlling an air-fuel ratio for an engine comprising the steps of: (a) detecting an output of an O 2 sensor; (b) comparing an output of said O 2 sensor which indicates a state of an air-fuel ratio of the engine with a predetermined value so as to produce a comparison result; (c) generating a control signal having a first proportional correction component and a predetermined integral slope based on said comparison result of the comparison in step (a), said steps (a), (b) and (c) being executed periodically at a first period; (d) adding a second proportional correction component to said control signal generated in step (c), to produce a corrected control signal, said step (d) being executed periodically at a second period which is longer than said first period; and (e) controlling the air-fuel ratio on the basis of said corrected control signal.
Claim 8
Independent Claim
146 words
A method of controlling an air-fuel ratio for an engine comprising the steps of: (a) detecting an output of an O 2 sensor; (b) comparing an output of said O 2 sensor which indicates a state of an air-fuel ratio of the engine with a predetermined value so as to produce a comparison result; (c) generating a control signal having a first proportional correction component and a predetermined integral slope based on said comparison result of the comparison in step (a), said steps (a), (b) and (c) being executed periodically at a first period; (d) adding a second proportional correction component to said control signal generated in step (c), to produce a corrected control signal, said step (d) being executed periodically at a second period which is longer than said first period; and (e) controlling the air-fuel ratio on the basis of said corrected control signal.
Claim 9
Dependent Claim
26 words
A method according to claim 6, wherein said second proportional correction component is added to said control signal while maintaining said predetermined integral slope without change.
Claim 10
Dependent Claim
20 words
A method according to claim 6, wherein said second proportional correction component has a value which varies with engine speed.
Claim 11
Dependent Claim
20 words
A method according to claim 6, wherein said second proportional correction component has a value which varies with engine load.
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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) | 1992-07-31 | 1993-01-30 | 1993-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-31 | 1997-01-30 | 1997-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-31 | 2001-01-30 | 2001-08-01 | $7700.00 | Window Closed / Lapsed |