US5363648A
Expired / Lapsed
US
⏱️ 0.0 years remaining
A/F ratio control system for internal combustion engine
Assignee: Honda Motor Co Ltd
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Filing: 1993-12-27
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Granted: 1994-11-15
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Expires: 2013-12-27
Abstract
Abstract A system for controlling an air/fuel ratio of a four-cylinder internal combustion engine. In the system, an actual air/fuel ratio, at least at upstream or downstream of a catalytic converter installed at an exhaust system of the engine, is intentionally oscillated at least either in its amplitude or cycle. A characteristic of a desired air/fuel ratio as a periodic function is established with respect to time such that the desired air/fuel ratio varies at least either at a predetermined amplitude or cycle within a predetermined period. The characteristic is sampled by a time interval determined on the basis of a time interval between TDC crank angle positions of the engine. Each cylinder's desired air/fuel ratio is then determined from the sampled data, and a fuel injection amount for each cylinder is determined from the respective cylinder's desired air/fuel ratios. Fuel is then supplied to each cylinder in response to the determined fuel injection amount. The actual air/fuel ratio at each cylinder is detected or estimated and feedback controlled to the desired air/fuel ratio.
Inventors
- 👤 Shusuke Akazaki
- 👤 Yusuke Hasegawa
- 👤 Yoichi Nishimura
- 👤 Isao Komoriya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:52
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/008; F02D41/02; F02D41/14; F02D41/1401; F02D41/1408; F02D41/1438; F02D41/1439; F02D41/1441; F02D41/1443; F02D2041/1413; F02D2041/1415; F02D2041/1416; F02D2041/1433; F02D41/1444; F02D41/1454; F02D41/1456
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
162 words
A system for controlling an air/fuel ratio of a multicylinder internal combustion engine such that an actual air/fuel ratio, at at least one of upstream and downstream of a catalytic converter installed at an exhaust system of the engine, is intentionally oscillated at least one of its amplitude and cycle, comprising: first means for establishing a characteristic of a desired air/fuel ratio as a periodic function such that the desired air/fuel ratio varies at at least one of a predetermined amplitude and cycle within a predetermined period; second means for sampling the characteristic by a time interval determined on the basis of a time interval between TDC crank angle positions of the engine; third means for determining each cylinder's desired air/fuel ratio from the sampled data; fourth means for determining a fuel injection amount for each cylinder from each determined cylinder's desired air/fuel ratio; and fifth means for supplying a fuel to each cylinder in response to the determined fuel injection amount.
Claim 2
Independent Claim
162 words
A system for controlling an air/fuel ratio of a multicylinder internal combustion engine such that an actual air/fuel ratio, at at least one of upstream and downstream of a catalytic converter installed at an exhaust system of the engine, is intentionally oscillated at least one of its amplitude and cycle, comprising: first means for establishing a characteristic of a desired air/fuel ratio as a periodic function such that the desired air/fuel ratio varies at at least one of a predetermined amplitude and cycle within a predetermined period; second means for sampling the characteristic by a time interval determined on the basis of a time interval between TDC crank angle positions of the engine; third means for determining each cylinder's desired air/fuel ratio from the sampled data; fourth means for determining a fuel injection amount for each cylinder from each determined cylinder's desired air/fuel ratio; and fifth means for supplying a fuel to each cylinder in response to the determined fuel injection amount.
Claim 3
Dependent Claim
24 words
A system according to claim 1, wherein said third means multiplies a coefficient by each determined cylinder's desired air/fuel ratio to adjust its amplitude.
Claim 4
Dependent Claim
113 words
A system according to claim 1, wherein said third means includes: sixth means for assuming an air/fuel ratio at a confluence point of the exhaust system of the engine as an average value made up of a sum of products of past firing histories of each cylinder weighted by a predetermined value, and establishing a model using air/fuel ratios of each cylinder as state variables; seventh means for obtaining a state equation with respect to the state variables; and an observer that observes the state variables; and said third means inputs the sampled data to the observer and determines each cylinder's desired air/fuel ratio on the basis of an output of the observer.
Claim 5
Dependent Claim
113 words
A system according to claim 2, wherein said third means includes: sixth means for assuming an air/fuel ratio at a confluence point of the exhaust system of the engine as an average value made up of a sum of products of past firing histories of each cylinder weighted by a predetermined value, and establishing a model using air/fuel ratios of each cylinder as state variables; seventh means for obtaining a state equation with respect to the state variables; and an observer that observes the state variables; and said third means inputs the sampled data to the observer and determines each cylinder's desired air/fuel ratio on the basis of an output of the observer.
Claim 6
Dependent Claim
31 words
A system according to claim 1, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to an engine operating parameter.
Claim 7
Dependent Claim
31 words
A system according to claim 2, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to an engine operating parameter.
Claim 8
Dependent Claim
31 words
A system according to claim 3, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to an engine operating parameter.
Claim 9
Dependent Claim
31 words
A system according to claim 4, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to an engine operating parameter.
Claim 10
Dependent Claim
21 words
A system according to claim 5, wherein the engine operating parameter is at least one of engine speed and engine load.
Claim 11
Dependent Claim
21 words
A system according to claim 6, wherein the engine operating parameter is at least one of engine speed and engine load.
Claim 12
Dependent Claim
21 words
A system according to claim 7, wherein the engine operating parameter is at least one of engine speed and engine load.
Claim 13
Dependent Claim
21 words
A system according to claim 8, wherein the engine operating parameter is at least one of engine speed and engine load.
Claim 14
Dependent Claim
35 words
A system according to claim 1, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 15
Dependent Claim
35 words
A system according to claim 2, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 16
Dependent Claim
35 words
A system according to claim 3, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 17
Dependent Claim
35 words
A system according to claim 4, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 18
Dependent Claim
35 words
A system according to claim 5, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 19
Dependent Claim
35 words
A system according to claim 6, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 20
Dependent Claim
35 words
A system according to claim 7, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 21
Dependent Claim
35 words
A system according to claim 8, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 22
Dependent Claim
35 words
A system according to claim 9, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 23
Dependent Claim
35 words
A system according to claim 10, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 24
Dependent Claim
35 words
A system according to claim 11, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 25
Dependent Claim
35 words
A system according to claim 12, wherein said third means varies at least one of the amplitude and cycle of the desired air/fuel ratio in response to a degree of degradation of the catalytic converter.
Claim 26
Dependent Claim
36 words
A system according to claim 1, wherein said third means determines the actual air/fuel ratio at each cylinder and determines each cylinder's desired air/fuel ratio such that a deviation from the determined actual air/fuel ratio decreases.
Claim 27
Dependent Claim
36 words
A system according to claim 2, wherein said third means determines the actual air/fuel ratio at each cylinder and determines each cylinder's desired air/fuel ratio such that a deviation from the determined actual air/fuel ratio decreases.
Claim 28
Dependent Claim
36 words
A system according to claim 3, wherein said third means determines the actual air/fuel ratio at each cylinder and determines each cylinder's desired air/fuel ratio such that a deviation from the determined actual air/fuel ratio decreases.
Claim 29
Dependent Claim
36 words
A system according to claim 5, wherein said third means determines the actual air/fuel ratio at each cylinder and determines each cylinder's desired air/fuel ratio such that a deviation from the determined actual air/fuel ratio decreases.
Claim 30
Dependent Claim
36 words
A system according to claim 13, wherein said third means determines the actual air/fuel ratio at each cylinder and determines each cylinder's desired air/fuel ratio such that a deviation from the determined actual air/fuel ratio decreases.
Claim 31
Dependent Claim
36 words
A system according to claim 25, wherein an air/fuel ratio sensor is provided for each cylinder and said third means determines the actual air/fuel ratio at each cylinder from an output of the air/fuel ratio sensor.
Claim 32
Dependent Claim
36 words
A system according to claim 26, wherein an air/fuel ratio sensor is provided for each cylinder and said third means determines the actual air/fuel ratio at each cylinder from an output of the air/fuel ratio sensor.
Claim 33
Dependent Claim
36 words
A system according to claim 27, wherein an air/fuel ratio sensor is provided for each cylinder and said third means determines the actual air/fuel ratio at each cylinder from an output of the air/fuel ratio sensor.
Claim 34
Dependent Claim
36 words
A system according to claim 28, wherein an air/fuel ratio sensor is provided for each cylinder and said third means determines the actual air/fuel ratio at each cylinder from an output of the air/fuel ratio sensor.
Claim 35
Dependent Claim
36 words
A system according to claim 29, wherein an air/fuel ratio sensor is provided for each cylinder and said third means determines the actual air/fuel ratio at each cylinder from an output of the air/fuel ratio sensor.
Claim 36
Dependent Claim
125 words
A system according to claim 25, further including: an air/fuel ratio sensor provided at a confluence point of the exhaust system; eighth means for assuming an output of the air/fuel ratio indicative of the actual air/fuel ratio at the confluence point of the exhaust system of the engine as an average value made up of a sum of products of past firing histories of each cylinder weighted by a predetermined value, and establishing a model using air/fuel ratios of each cylinder as state variables; ninth means for obtaining a state equation with respect to the state variables; and an observer that observes the state variables; and said third means determines the each cylinder's actual air/fuel ratio on the basis of an output of the observer.
Claim 37
Dependent Claim
125 words
A system according to claim 26, further including: an air/fuel ratio sensor provided at a confluence point of the exhaust system; eighth means for assuming an output of the air/fuel ratio indicative of the actual air/fuel ratio at the confluence point of the exhaust system of the engine as an average value made up of a sum of products of past firing histories of each cylinder weighted by a predetermined value, and establishing a model using air/fuel ratios of each cylinder as state variables; ninth means for obtaining a state equation with respect to the state variables; and an observer that observes the state variables; and said third means determines the each cylinder's actual air/fuel ratio on the basis of an output of the observer.
Claim 38
Dependent Claim
125 words
A system according to claim 27, further including: an air/fuel ratio sensor provided at a confluence point of the exhaust system; eighth means for assuming an output of the air/fuel ratio indicative of the actual air/fuel ratio at the confluence point of the exhaust system of the engine as an average value made up of a sum of products of past firing histories of each cylinder weighted by a predetermined value, and establishing a model using air/fuel ratios of each cylinder as state variables; ninth means for obtaining a state equation with respect to the state variables; and an observer that observes the state variables; and said third means determines the each cylinder's actual air/fuel ratio on the basis of an output of the observer.
Claim 39
Dependent Claim
125 words
A system according to claim 28, further including: an air/fuel ratio sensor provided at a confluence point of the exhaust system; eighth means for assuming an output of the air/fuel ratio indicative of the actual air/fuel ratio at the confluence point of the exhaust system of the engine as an average value made up of a sum of products of past firing histories of each cylinder weighted by a predetermined value, and establishing a model using air/fuel ratios of each cylinder as state variables; ninth means for obtaining a state equation with respect to the state variables; and an observer that observes the state variables; and said third means determines the each cylinder's actual air/fuel ratio on the basis of an output of the observer.
Claim 40
Dependent Claim
125 words
A system according to claim 29, further including: an air/fuel ratio sensor provided at a confluence point of the exhaust system; eighth means for assuming an output of the air/fuel ratio indicative of the actual air/fuel ratio at the confluence point of the exhaust system of the engine as an average value made up of a sum of products of past firing histories of each cylinder weighted by a predetermined value, and establishing a model using air/fuel ratios of each cylinder as state variables; ninth means for obtaining a state equation with respect to the state variables; and an observer that observes the state variables; and said third means determines the each cylinder's actual air/fuel ratio on the basis of an output of the observer.
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) | 1997-11-14 | 1998-05-16 | 1998-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-11-14 | 2002-05-16 | 2002-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-11-14 | 2006-05-16 | 2006-11-15 | $7700.00 | Window Closed / Lapsed |