US5157920A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and an apparatus for controlling the air-fuel ratio of an internal combustion engine
Assignee: Hitachi Unisia Automotive Ltd
•
Filing: 1991-05-07
•
Granted: 1992-10-27
•
Expires: 2011-05-07
Abstract
Abstract An air-fuel ratio controlling apparatus for an internal combustion engine carries out air-fuel ratio feedback control with use of oxygen sensors, which are disposed on the upstream and downstream sides of a three-way catalytic converter respectively. A correction target value for a rich/lean balance of the feedback control carried out based on the output of the upstream oxygen sensor is corrected according to the output of the downstream oxygen sensor. A control quantity for the feedback control is corrected to reduce a difference between the correction target value and an actual value. This arrangement compensates a shift of an air-fuel ratio control point due to a change in the output characteristics of the upstream oxygen sensor, prevents an excessive deviation of an air-fuel ratio, and maintains an exhaust gas at a preferable level.
Inventors
- 👤 Shimpei Nakaniwa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:39
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1439; F02D41/1441; F01; F01N; F01N2430/00; F01N2430/06
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
210 words
A method of controlling the air-fuel ratio of an internal combustion engine, employing first and second air-fuel ratio sensors disposed on the upstream and downstream sides, respectively, of an exhaust purifying catalytic converter disposed in an exhaust system of the internal combustion engine, output values of the air-fuel ratio sensors changing in response to the concentration of a specific component contained in an exhaust from the engine, the concentration changing according to the air-fuel ratio of an intake air-fuel mixture to the engine, comprising a step of carrying out feedback control for controlling the air-fuel ratio of the intake air-fuel mixture to the engine to a target air-fuel ratio according to the output of the first air-fuel ratio sensor, a step of calculating the total of lean-oriented control quantities and the total of rich-oriented control quantities applied for an air-fuel ratio during the air-fuel ratio feedback control, a step of variably setting, according to the output of the second air-fuel ratio sensor, a correction target value for a parameter indicating the degree of difference between the totals, and a step of variably setting a control quantity for the air-fuel ratio feedback control to let the parameter indicating the degree of difference between the totals agree with the correction target value.
Claim 2
Independent Claim
210 words
A method of controlling the air-fuel ratio of an internal combustion engine, employing first and second air-fuel ratio sensors disposed on the upstream and downstream sides, respectively, of an exhaust purifying catalytic converter disposed in an exhaust system of the internal combustion engine, output values of the air-fuel ratio sensors changing in response to the concentration of a specific component contained in an exhaust from the engine, the concentration changing according to the air-fuel ratio of an intake air-fuel mixture to the engine, comprising a step of carrying out feedback control for controlling the air-fuel ratio of the intake air-fuel mixture to the engine to a target air-fuel ratio according to the output of the first air-fuel ratio sensor, a step of calculating the total of lean-oriented control quantities and the total of rich-oriented control quantities applied for an air-fuel ratio during the air-fuel ratio feedback control, a step of variably setting, according to the output of the second air-fuel ratio sensor, a correction target value for a parameter indicating the degree of difference between the totals, and a step of variably setting a control quantity for the air-fuel ratio feedback control to let the parameter indicating the degree of difference between the totals agree with the correction target value.
Claim 3
Dependent Claim
39 words
A method of controlling the air-fuel ratio of an internal combustion engine according to claim 1, wherein the first and second air-fuel ratio sensors change their output values in response to the concentration of oxygen contained in the exhaust.
Claim 4
Dependent Claim
35 words
A method of controlling the air-fuel ratio of an internal combustion engine according to claim 1, wherein the air-fuel ratio feedback control is carried out on the quantity of a fuel supplied to the engine.
Claim 5
Dependent Claim
62 words
A method of controlling the air-fuel ratio of an internal combustion engine according to claim 1, wherein the total of lean-oriented control quantities and the total of rich-oriented control quantities are found when an actual air-fuel ratio detected by the first air-fuel ratio sensor is inverted from rich to lean or from lean to rich with respect to the target air-fuel ratio.
Claim 6
Dependent Claim
31 words
A method of controlling the air-fuel ratio of an internal combustion engine according to claim 1, wherein each of the totals of lean- and rich-oriented control quantities is weighted and averaged.
Claim 7
Dependent Claim
57 words
A method of controlling the air-fuel ratio of an internal combustion engine according to claim 1, wherein the correction target value is gradually changed by a predetermined amount so that the output of the second air-fuel ratio sensor may approach a value corresponding to the same target air-fuel ratio as that for the air-fuel ratio feedback control.
Claim 8
Dependent Claim
57 words
A method of controlling the air-fuel ratio of an internal combustion engine according to claim 1, wherein a predetermined dead zone is prepared for output values of the second air-fuel ratio sensor, and when an output value of the second air-fuel ratio sensor is within the dead zone, the correction target value is unchanged for the moment.
Claim 9
Dependent Claim
60 words
A method of controlling the air-fuel ratio of an internal combustion engine according to claim 1, wherein a correction value for the control quantity is set according to a deviation of the parameter indicating the difference between the lean- and rich-oriented control quantity totals and the correction target value, and the control quantity is changed according to the correction value.
Claim 10
Independent Claim
236 words
An apparatus for controlling the air-fuel ratio of an internal combustion engine comprising: first and second air-fuel ratio sensors disposed on the upstream and downstream sides, respectively, of an exhaust purifying catalytic converter disposed in an exhaust system of the internal combustion engine, whereby output values of the air-fuel ratio sensors change in response to the concentration of a specific component contained in an exhaust from the engine, and the concentration changes according to the air-fuel ratio of an intake air-fuel mixture to the engine; an air-fuel ratio feedback control means for carrying out feedback control for controlling the air-fuel ratio of an intake air-fuel mixture to the engine to a target air-fuel ratio according to the output of the first air-fuel ratio sensor; a total control quantity calculation means for calculating the total of lean-oriented control quantities and the total of rich-oriented control quantities for an air-fuel ratio during the air-fuel ratio feedback control; a control quantity setting means for variably setting a control quantity used for the air-fuel ratio feedback control means so that a parameter indicating the degree of difference between the total of lean-oriented control quantities and the total of rich-oriented control quantities calculated in the total control quantity calculation means becomes equal to the correction target value; and a correction target value setting means for changing the correction target value according to an output value of the second air-fuel ratio sensor.
Claim 11
Independent Claim
236 words
An apparatus for controlling the air-fuel ratio of an internal combustion engine comprising: first and second air-fuel ratio sensors disposed on the upstream and downstream sides, respectively, of an exhaust purifying catalytic converter disposed in an exhaust system of the internal combustion engine, whereby output values of the air-fuel ratio sensors change in response to the concentration of a specific component contained in an exhaust from the engine, and the concentration changes according to the air-fuel ratio of an intake air-fuel mixture to the engine; an air-fuel ratio feedback control means for carrying out feedback control for controlling the air-fuel ratio of an intake air-fuel mixture to the engine to a target air-fuel ratio according to the output of the first air-fuel ratio sensor; a total control quantity calculation means for calculating the total of lean-oriented control quantities and the total of rich-oriented control quantities for an air-fuel ratio during the air-fuel ratio feedback control; a control quantity setting means for variably setting a control quantity used for the air-fuel ratio feedback control means so that a parameter indicating the degree of difference between the total of lean-oriented control quantities and the total of rich-oriented control quantities calculated in the total control quantity calculation means becomes equal to the correction target value; and a correction target value setting means for changing the correction target value according to an output value of the second air-fuel ratio sensor.
Claim 12
Dependent Claim
39 words
An apparatus for controlling the air-fuel ratio of an internal combustion engine according to claim 9, wherein the first and second air-fuel ratio sensors change their output values in response to the concentration of oxygen contained in the exhaust.
Claim 13
Dependent Claim
55 words
An apparatus for controlling the air-fuel ratio of an internal combustion engine according to claim 9, wherein the air-fuel ratio feedback control means carries out feedback control on the quantity of a fuel supplied to the engine, thereby controlling the air-fuel ratio of an intake air-fuel mixture to the engine to the target air-fuel ratio.
Claim 14
Dependent Claim
62 words
An apparatus for controlling the air-fuel ratio of an internal combustion engine according to claim 9, wherein the total of lean-oriented control quantities and the total of rich-oriented control quantities are found when an actual air-fuel ratio detected by the first air-fuel ratio sensor is inverted from rich to lean or from lean to rich with respect to the target air-fuel ratio.
Claim 15
Dependent Claim
38 words
An apparatus for controlling the air-fuel ratio of an internal combustion engine according to claim 9, wherein the total control quantity calculation means obtains each of the lean- and rich-oriented control quantity totals through a weighted average operation.
Claim 16
Dependent Claim
63 words
An apparatus for controlling the air-fuel ratio of an internal combustion engine according to claim 9, wherein the correction target value setting means gradually changes the correction target value by a predetermined amount so that the output value of the second air-fuel ratio sensor may approach a value corresponding to the same target air-fuel ratio as that for the air-fuel ratio feedback control.
Claim 17
Dependent Claim
65 words
An apparatus for controlling the air-fuel ratio of an internal combustion engine according to claim 9, wherein a predetermined dead zone is prepared for output values of the second air-fuel ratio sensor, and when an output value of the second air-fuel ratio sensor is within the dead zone, whereby the correction target value setting means does not change the correction target value for the moment.
Claim 18
Dependent Claim
63 words
An apparatus for controlling the air-fuel ratio of an internal combustion engine according to claim 9, wherein the control quantity setting means sets a correction value for the control quantity according to a deviation of the parameter indicating the difference between the lean- and rich-oriented control quantity totals from the correction target value, and changes the control quantity according to the correction value.
References Cited (Backward Citations)
JPS52102394A
Cited
JPS5848756A
Cited
JPS5872647A
Cited
US4745741A
Cited
US4703619A
Cited
US4712373A
Cited
JPS6229737A
Cited
US4761950A
Cited
US4779414A
Cited
JPS6357843A
Cited
US4796425A
Cited
JPH01300034A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-10-27 | 1996-04-27 | 1996-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-27 | 2000-04-27 | 2000-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-27 | 2004-04-27 | 2004-10-27 | $7700.00 | Window Closed / Lapsed |