US5033440A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for controlling air/fuel ratio of internal combustion engine
Assignee: Mitsubishi Motors Corp
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Filing: 1990-06-27
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Granted: 1991-07-23
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Expires: 2010-06-27
Abstract
Abstract An apparatus is provided for controlling the air/fuel ratio of an internal combustion engine. The apparatus includes a sensor disposed in an exhaust system for detecting components of exhaust gas, a device for compulsorily changing the air/fuel ratio, another device for setting a first target value which gives a target air/fuel ratio to be compared with each output from the sensor, and a further device for controlling the air/fuel ratio, which has been compulsorily changed by the air/fuel ratio changing device, on the basis of the result of a comparison between the output and the first target value, whereby the average air/fuel ratio may be controlled to the first target air/fuel ratio. The first target value setting device includes an element for modifying the first target value to a second target value, which gives a leaner air/fuel ratio, in a specific operation state of the engine.
Inventors
- 👤 Shiro Kumagai
- 👤 Yoshiaki Kodama
- 👤 Nobuyuki Yasuda
- 👤 Katsuyuki Maeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:10
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/04; F02D41/14; F02D41/1438; F02D41/1477; F02D41/1479; F02D41/24; F02D41/2406; F02D41/2425; F02D41/2429; F02D41/2438; F02D41/2451; F02D41/2454
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
177 words
An apparatus for controlling the air/fuel ratio of an internal combustion engine equipped with a catalytic converter disposed in an exhaust system, comprising: a means disposed in the exhaust system for detecting components of exhaust gas; a means for compulsorily changing the air/fuel ratio with a desired amplitude at a desired cycle; a means for setting a first target value which gives a target air/fuel ratio to be compared with each output from said exhaust gas detection means; and a means for controlling the air/fuel ratio, which has been compulsorily changed by said air/fuel ratio changing means, on the basis of the result of a comparison between the output from said exhaust gas detection means and the first target value from said target value setting means, whereby the average air/fuel ratio may be controlled to the first target air/fuel ratio; and said first target value setting means having a means for modifying the first target value to a second target value, which gives a leaner air/fuel ratio, in a specific operation state of the internal combustion engine.
Claim 2
Independent Claim
177 words
An apparatus for controlling the air/fuel ratio of an internal combustion engine equipped with a catalytic converter disposed in an exhaust system, comprising: a means disposed in the exhaust system for detecting components of exhaust gas; a means for compulsorily changing the air/fuel ratio with a desired amplitude at a desired cycle; a means for setting a first target value which gives a target air/fuel ratio to be compared with each output from said exhaust gas detection means; and a means for controlling the air/fuel ratio, which has been compulsorily changed by said air/fuel ratio changing means, on the basis of the result of a comparison between the output from said exhaust gas detection means and the first target value from said target value setting means, whereby the average air/fuel ratio may be controlled to the first target air/fuel ratio; and said first target value setting means having a means for modifying the first target value to a second target value, which gives a leaner air/fuel ratio, in a specific operation state of the internal combustion engine.
Claim 3
Dependent Claim
16 words
The apparatus of claim 1, wherein the first target air/fuel ratio is a stoichiometric air/fuel ratio.
Claim 4
Dependent Claim
15 words
The apparatus of claim 2, wherein the specific operation state is a low-load operation state.
Claim 5
Dependent Claim
17 words
The apparatus of claim 3, wherein the low-load operation state is a low-speed and low-load operation state.
Claim 6
Dependent Claim
15 words
The apparatus of claim 3, wherein the low-load operation state is an idling operation state.
Claim 7
Dependent Claim
16 words
The apparatus of claim 2, wherein the specific operation state is a small intake-air-quantity operation state.
Claim 8
Dependent Claim
44 words
The apparatus of claim 6, further comprising a means for detecting the quantity of intake air, whereby the internal combustion engine is judged to be in the small intake-air-quantity operation state when an output from said intake-air-quantity detection means falls below a predetermined value.
Claim 9
Dependent Claim
40 words
The apparatus of claim 7, wherein said intake-air-quantity detection means is a Karman sensor which outputs a pulse signal of a frequency based on Karman vortices of intake air and corresponding to information on the quantity of the intake air.
Claim 10
Dependent Claim
47 words
The apparatus of claim 1, wherein the compulsory change of the air/fuel ratio is effected by said air/fuel ratio changing means on the basis of results of a proportional-plus-integral operation for the difference between an output from said exhaust gas detection means and the first target value.
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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) | 1994-07-22 | 1995-01-21 | 1995-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-22 | 1999-01-21 | 1999-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-22 | 2003-01-21 | 2003-07-23 | $7700.00 | Window Closed / Lapsed |