US4763629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air-fuel ratio control system for engine
Assignee: Mazda Motor Corp
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Filing: 1987-02-12
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Granted: 1988-08-16
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Expires: 2007-02-12
Abstract
Abstract An air-fuel ratio control system for an engine in which a fuel injection amount is calculated according to the engine operating conditions and is corrected according to the output of an air-fuel ratio sensor, comprises a base fuel injection amount calculating section for calculating a base fuel injection amount corresponding to the stoichiometric air-fuel ratio on the basis of the intake air amount, a target air-fuel ratio calculating section for calculating a target air-fuel ratio according to the engine operating condition, a reference value calculating section for calculating a reference value which represents the target air-fuel ratio and is submitted to comparison with the output of the air-fuel ratio sensor, a feedback correction coefficient calculating section for calculating a feedback coefficient according to the deviation of the output of the air-fuel ratio sensor from the reference value, and a final fuel injection amount calculating section which corrects the base fuel-injection amount on the basis of the ratio of the stoichiometric air-fuel ratio to the target air-fuel ratio and the feedback coefficient to obtain a final fuel injection amount.
Inventors
- 👤 Katsumi Okazaki
- 👤 Katsuhiko Yokooku
- 👤 Tomomi Watanabe
- 👤 Tadataka Nakazumi
- 👤 Kiyotaka Mamiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:54
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1486; F02D41/1477; F02D41/1479; F02D41/18; F02D41/182; F02D41/1444; F02D41/1454; F02D41/1456
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
249 words
An air-fuel ratio control system for an engine in which a fuel injection amount is calculated according to the engine operating conditions of at least engine load and speed and is adjusted according to the output of an air-fuel ratio sensor, comprising means for measuring the intake air amount, a base fuel injection amount calculating means responsive to said means for measuring the intake air amount for calculating a base fuel injection amount corresponding to the stoichiometric air-fuel ratio, a target air-fuel ratio calculating means for calculating a target air-fuel ratio according to said engine operating conditions, a reference value calculating means responsive to the output of the target air-fuel ratio calculating means for calculating a reference value which is a function of the target air fuel ratio, comparision means for comparing the output of the air-fuel ratio sensor and the reference value, a feedback correction coefficient calculating means for calculating a feedback coefficient according to any deviation of the output of the air-fuel ratio sensor from the reference value as determined by the comparision means, and a final fuel injection amount calculating means responsive to the outputs of the base fuel injection amount calculating means, the target air-fuel ratio calculating means, and the feedback correction coefficient calculating means to adjust the base fuel-injection amount where the latter adjustment is a function of (a) the ratio of the stoichiometric air-fuel ratio to the target air-fuel ratio and (b) the feedback coefficient to thus obtain a final fuel injection amount.
Claim 2
Dependent Claim
249 words
An air-fuel ratio control system for an engine in which a fuel injection amount is calculated according to the engine operating conditions of at least engine load and speed and is adjusted according to the output of an air-fuel ratio sensor, comprising means for measuring the intake air amount, a base fuel injection amount calculating means responsive to said means for measuring the intake air amount for calculating a base fuel injection amount corresponding to the stoichiometric air-fuel ratio, a target air-fuel ratio calculating means for calculating a target air-fuel ratio according to said engine operating conditions, a reference value calculating means responsive to the output of the target air-fuel ratio calculating means for calculating a reference value which is a function of the target air fuel ratio, comparision means for comparing the output of the air-fuel ratio sensor and the reference value, a feedback correction coefficient calculating means for calculating a feedback coefficient according to any deviation of the output of the air-fuel ratio sensor from the reference value as determined by the comparision means, and a final fuel injection amount calculating means responsive to the outputs of the base fuel injection amount calculating means, the target air-fuel ratio calculating means, and the feedback correction coefficient calculating means to adjust the base fuel-injection amount where the latter adjustment is a function of (a) the ratio of the stoichiometric air-fuel ratio to the target air-fuel ratio and (b) the feedback coefficient to thus obtain a final fuel injection amount.
Claim 3
Dependent Claim
49 words
An air-fuel ratio control system as defined in claim 1 in which said final fuel injection amount calculating means calculates the final fuel injection amount by multiplying the base fuel injection amount by the ratio of the stoichiometric air-fuel ratio to the target air-fuel ratio and the feedback coefficient.
Claim 4
Dependent Claim
37 words
An air-fuel ratio control system as defined in claim 1 further comprising a feedback condition determining means which determines that the feedback control is to be effected when the target air-fuel ratio is in a predetermined range.
Claim 5
Dependent Claim
27 words
An air-fuel ratio control system as defined in claim 3 in which the target air-fuel ratio is leaner than the stoichiometric air-fuel ratio in said predetermined range.
Claim 6
Dependent Claim
261 words
An air-fuel ratio control system for an engine in which a fuel injection amount is calculated according to the engine operating conditions of at least engine load and speed and is adjusted according to the output of an air-fuel ratio sensor, comprising means for measuring at least one of said engine operating conditions, a base fuel injection amount calculating means responsive to said means for measuring said one operating condition for calculating a base fuel injection amount, a base target air-fuel ratio calculating means for calculating a target air-fuel ratio according to at least one of said engine operating conditions, a target air-fuel ratio adjusting means for correcting the base target air-fuel according to at least another one of said engine operating conditions thereby obtaining an adjusted target air-fuel ratio, a reference value calculating means responsive to the output of the target air-fuel ratio adjusting means for calculating a reference value which is a function of the adjusted target air-fuel ratio, comparision means for comparing the output of the air-fuel ratio sensor, a feedback correction coefficient calculating means for calculating a feedback coefficient according to any deviation of the output of the air-fuel ratio sensor from the reference value as determined by the comparision means, and a final fuel injection amount calculating means responsive to the outputs of the base fuel injection amount calculating means, the target air-fuel ratio adjusting means, and the feedback correction coefficient calculating means to adjust the base fuel-injection amount of the adjusting target air-fuel ratio and the feedback coefficient to obtain a final fuel injection amount.
Claim 7
Dependent Claim
261 words
An air-fuel ratio control system for an engine in which a fuel injection amount is calculated according to the engine operating conditions of at least engine load and speed and is adjusted according to the output of an air-fuel ratio sensor, comprising means for measuring at least one of said engine operating conditions, a base fuel injection amount calculating means responsive to said means for measuring said one operating condition for calculating a base fuel injection amount, a base target air-fuel ratio calculating means for calculating a target air-fuel ratio according to at least one of said engine operating conditions, a target air-fuel ratio adjusting means for correcting the base target air-fuel according to at least another one of said engine operating conditions thereby obtaining an adjusted target air-fuel ratio, a reference value calculating means responsive to the output of the target air-fuel ratio adjusting means for calculating a reference value which is a function of the adjusted target air-fuel ratio, comparision means for comparing the output of the air-fuel ratio sensor, a feedback correction coefficient calculating means for calculating a feedback coefficient according to any deviation of the output of the air-fuel ratio sensor from the reference value as determined by the comparision means, and a final fuel injection amount calculating means responsive to the outputs of the base fuel injection amount calculating means, the target air-fuel ratio adjusting means, and the feedback correction coefficient calculating means to adjust the base fuel-injection amount of the adjusting target air-fuel ratio and the feedback coefficient to obtain a final fuel injection amount.
Claim 8
Dependent Claim
23 words
An air-fuel ratio control system as defined in claim 5 in which said engine condition represents the temperature of the engine cooling water.
Claim 9
Dependent Claim
39 words
An air-fuel ratio control system as defined in claim 1 in which said engine operating condition is determined by engine speed and engine load, and said target air-fuel ratio is predetermined based on said engine speed and engine load.
Claim 10
Dependent Claim
39 words
An air-fuel ratio control system as defined in claim 7 in which said engine load is determined by throttle opening and intake air amount, and a throttle opening-engine speed map and an intake air amount-engine speed map are provided.
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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) | 1991-08-16 | 1992-02-15 | 1992-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-16 | 1996-02-15 | 1996-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-16 | 2000-02-15 | 2000-08-16 | $7700.00 | Window Closed / Lapsed |