Patent US3331256A successfully refreshed from Google Patents.
Patent US5678402A successfully refreshed from Google Patents.
US5678402A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air-fuel ratio control system for internal combustion engines and exhaust system temperature-estimating device applicable thereto
Assignee: Honda Motor Co Ltd
•
Filing: 1995-03-23
•
Granted: 1997-10-21
•
Expires: 2015-03-23
Abstract
Abstract An air-fuel ratio control system for an internal combustion engine has a catalytic converter arranged in an exhaust passage. A maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in the catalytic converter is calculated. The air-fuel ratio of a mixture supplied to the engine is forcibly oscillated at a predetermined frequency and a predetermined amplitude. At least one of the predetermined frequency and the predetermined amplitude is changed at a predetermined rate of change. A predetermined rate of change of the at least one of the predetermined frequency and the predetermined amplitude is set in dependence on the maximum oxygen storage amount to thereby secure the maximum purification rate of the catalytic converter.
Inventors
- 👤 Hiroshi Kitagawa
- 👤 Seiji Hatcho
- 👤 Tetsuya Kaneko
- 👤 Akira Kato
- 👤 Toshiaki Hirota
- 👤 Masami Watanabe
- 👤 Jun Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:45
CPC Classifications
F; F01; F01N; F01N9/00; F01N9/005; F01N11/00; F01N11/002; F01N11/007; F02; F02D; F02D41/00; F02D41/02; F02D41/021; F02D41/0235; F02D41/0295; F02D41/14; F02D41/1401; F02D41/1408; F02D41/1438; F02D41/1439; F02D41/1441; F02D41/1477; F01N2900/00; F01N2900/04; F01N2900/0422; F02D2200/00; F02D2200/02; F02D2200/08; F02D2200/0802; F02D2200/0804; F02D2200/0816; F02D41/1444; F02D41/1454; F02D41/1456; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
128 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, and a catalytic converter arranged in said exhaust passage, comprising: maximum oxygen storage amount-calculating means for calculating a maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in said catalytic converter; forcible oscillating means for forcibly oscillating an air-fuel ratio of a mixture supplied to said engine at a predetermined frequency and a predetermined amplitude; oscillation-changing means for changing at least one of said predetermined frequency and said predetermined amplitude at a predetermined rate of change; and change rate-setting means for setting said predetermined rate of change of said at least one of said predetermined frequency and said predetermined amplitude, in dependence on said maximum oxygen storage amount.
Claim 2
Dependent Claim
128 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, and a catalytic converter arranged in said exhaust passage, comprising: maximum oxygen storage amount-calculating means for calculating a maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in said catalytic converter; forcible oscillating means for forcibly oscillating an air-fuel ratio of a mixture supplied to said engine at a predetermined frequency and a predetermined amplitude; oscillation-changing means for changing at least one of said predetermined frequency and said predetermined amplitude at a predetermined rate of change; and change rate-setting means for setting said predetermined rate of change of said at least one of said predetermined frequency and said predetermined amplitude, in dependence on said maximum oxygen storage amount.
Claim 3
Dependent Claim
45 words
An air-fuel ratio control system according to claim 1, wherein said maximum oxygen storage amount-calculating means calculates said maximum oxygen storage amount based on at least one of temperature of a catalyst of said catalytic converter and a degree of deterioration of said catalytic converter.
Claim 4
Dependent Claim
121 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, and a catalytic converter arranged in said exhaust passage, comprising: exhaust gas amount-calculating means for calculating an exhaust gas amount indicative of an amount of exhaust gases supplied to said catalytic converter; forcible oscillating means for forcibly oscillating an air-fuel ratio of a mixture supplied to said engine at predetermined frequency and a predetermined amplitude; oscillation-changing means for changing at least one of said predetermined frequency and said predetermined amplitude at a predetermined rate of change; and change rate-setting means for setting a predetermined rate of change of said at least one of said predetermined frequency and said predetermined amplitude in dependence on said exhaust gas amount.
Claim 5
Dependent Claim
121 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, and a catalytic converter arranged in said exhaust passage, comprising: exhaust gas amount-calculating means for calculating an exhaust gas amount indicative of an amount of exhaust gases supplied to said catalytic converter; forcible oscillating means for forcibly oscillating an air-fuel ratio of a mixture supplied to said engine at predetermined frequency and a predetermined amplitude; oscillation-changing means for changing at least one of said predetermined frequency and said predetermined amplitude at a predetermined rate of change; and change rate-setting means for setting a predetermined rate of change of said at least one of said predetermined frequency and said predetermined amplitude in dependence on said exhaust gas amount.
Claim 6
Dependent Claim
32 words
An air-fuel ratio control system according to claim 3, wherein said exhaust gas amount-calculating means determines said exhaust gas amount, based on load on said engine and rotational speed of said engine.
Claim 7
Dependent Claim
133 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, a catalytic converter arranged in said exhaust passage, and an oxygen sensor arranged in said exhaust passage at a location upstream of said catalytic converter, comprising: maximum oxygen storage amount-calculating means for calculating a maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in said catalytic converter; air-fuel ratio feedback control means for calculating an air-fuel ratio feedback control amount, based on an output from said oxygen sensor and a feedback control constant; control amount-changing means for changing said air-fuel ratio feedback control constant at a predetermined rate of change; and change rate-setting means for setting said predetermined rate of change of said feedback control constant, based on said maximum oxygen storage amount.
Claim 8
Dependent Claim
133 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, a catalytic converter arranged in said exhaust passage, and an oxygen sensor arranged in said exhaust passage at a location upstream of said catalytic converter, comprising: maximum oxygen storage amount-calculating means for calculating a maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in said catalytic converter; air-fuel ratio feedback control means for calculating an air-fuel ratio feedback control amount, based on an output from said oxygen sensor and a feedback control constant; control amount-changing means for changing said air-fuel ratio feedback control constant at a predetermined rate of change; and change rate-setting means for setting said predetermined rate of change of said feedback control constant, based on said maximum oxygen storage amount.
Claim 9
Dependent Claim
45 words
An air-fuel ratio control system according to claim 5, wherein said maximum oxygen storage amount-calculating means calculates said maximum oxygen storage amount, based on at least one of temperature of a catalyst of said catalytic converter and a degree of deterioration of said catalytic converter.
Claim 10
Dependent Claim
42 words
An air-fuel ratio control system according to claim 5, wherein said air-fuel ratio feedback control constant comprises a proportional term and a delay time period for delaying operation of said 5 proportional term after said output from said oxygen sensor is inverted.
Claim 11
Dependent Claim
127 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, a catalytic converter arranged in said exhaust passage, and an oxygen. sensor arranged in said exhaust passage at a location upstream of said catalytic converter, comprising: exhaust gas amount-calculating means for calculating an exhaust gas amount indicative of an amount of exhaust gases supplied to said catalytic converter; air-fuel ratio feedback control means for calculating an air-fuel ratio feedback control amount, based on an output from said oxygen sensor and a feedback control constant; control amount-changing means for changing said air-fuel ratio feedback control constant at a predetermined rate of change; and change rate-setting means for setting said predetermined rate of change of said feedback control constant, based on said exhaust gas amount.
Claim 12
Dependent Claim
127 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, a catalytic converter arranged in said exhaust passage, and an oxygen. sensor arranged in said exhaust passage at a location upstream of said catalytic converter, comprising: exhaust gas amount-calculating means for calculating an exhaust gas amount indicative of an amount of exhaust gases supplied to said catalytic converter; air-fuel ratio feedback control means for calculating an air-fuel ratio feedback control amount, based on an output from said oxygen sensor and a feedback control constant; control amount-changing means for changing said air-fuel ratio feedback control constant at a predetermined rate of change; and change rate-setting means for setting said predetermined rate of change of said feedback control constant, based on said exhaust gas amount.
Claim 13
Dependent Claim
33 words
An air-fuel ratio control system according to claim 8, wherein said exhaust gas amount-calculating means determines said amount of exhaust gases, based on load on said engine and rotational speed of said engine.
Claim 14
Dependent Claim
41 words
An air-fuel ratio control system according to claim 8, wherein said air-fuel ratio feedback control constant comprises a proportional term and a delay time period for delaying operation of said proportional term after said output from said oxygen sensor is inverted.
Claim 15
Dependent Claim
122 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, and a catalytic converter arranged in said exhaust passage, comprising: maximum oxygen storage amount-calculating means for calculating a maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in said catalytic converter; exhaust gas amount-calculating means for calculating an exhaust gas amount indicative of an amount of exhaust gases supplied to said catalytic converter; forcible oscillating means for forcibly oscillating an air-fuel ratio of a mixture supplied to said engine at a predetermined frequency and a predetermined amplitude; and setting means for setting said predetermined frequency and said predetermined amplitude, in dependence on said maximum oxygen storage amount and said exhaust gas amount.
Claim 16
Dependent Claim
122 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, and a catalytic converter arranged in said exhaust passage, comprising: maximum oxygen storage amount-calculating means for calculating a maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in said catalytic converter; exhaust gas amount-calculating means for calculating an exhaust gas amount indicative of an amount of exhaust gases supplied to said catalytic converter; forcible oscillating means for forcibly oscillating an air-fuel ratio of a mixture supplied to said engine at a predetermined frequency and a predetermined amplitude; and setting means for setting said predetermined frequency and said predetermined amplitude, in dependence on said maximum oxygen storage amount and said exhaust gas amount.
Claim 17
Dependent Claim
149 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, a catalytic converter arranged in said exhaust passage, and an oxygen sensor arranged in said exhaust passage at a location upstream of said catalytic converter, comprising: control amount-calculating means for calculating an air-fuel ratio feedback control amount, based on a predetermined Proportional term when a predetermined delay time period elapses after said output from said oxygen sensor is inverted. maximum oxygen storage amount-calculating means for calculating a maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in said-catalytic converter; exhaust gas amount-calculating means for calculating an exhaust gas amount indicative of an amount of exhaust gases supplied to said catalytic converter; and setting means for setting said predetermined proportional term and said predetermined delay time period, in dependence on said maximum oxygen storage amount and said exhaust gas amount.
Claim 18
Dependent Claim
149 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, a catalytic converter arranged in said exhaust passage, and an oxygen sensor arranged in said exhaust passage at a location upstream of said catalytic converter, comprising: control amount-calculating means for calculating an air-fuel ratio feedback control amount, based on a predetermined Proportional term when a predetermined delay time period elapses after said output from said oxygen sensor is inverted. maximum oxygen storage amount-calculating means for calculating a maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in said-catalytic converter; exhaust gas amount-calculating means for calculating an exhaust gas amount indicative of an amount of exhaust gases supplied to said catalytic converter; and setting means for setting said predetermined proportional term and said predetermined delay time period, in dependence on said maximum oxygen storage amount and said exhaust gas amount.
Claim 19
Dependent Claim
119 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, and a catalytic converter arranged in said exhaust passage, comprising: oxygen amount-calculating means for calculating an amount of oxygen stored in said catalytic converter; maximum oxygen storage amount-calculating means for calculating a maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in said catalytic converter; air-fuel ratio control means for controlling an air-fuel ratio of a mixture supplied to said engine such that said amount of oxygen stored in said catalytic converter falls within a predetermined range within said maximum oxygen storage amount; and changing means for changing said predetermined range in dependence on operating conditions of said engine.
Claim 20
Dependent Claim
119 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, and a catalytic converter arranged in said exhaust passage, comprising: oxygen amount-calculating means for calculating an amount of oxygen stored in said catalytic converter; maximum oxygen storage amount-calculating means for calculating a maximum oxygen storage amount indicative of the maximum amount of oxygen that can be stored in said catalytic converter; air-fuel ratio control means for controlling an air-fuel ratio of a mixture supplied to said engine such that said amount of oxygen stored in said catalytic converter falls within a predetermined range within said maximum oxygen storage amount; and changing means for changing said predetermined range in dependence on operating conditions of said engine.
Claim 21
Dependent Claim
41 words
An air-fuel ratio control system according to claim 13, wherein said operating conditions of said engine includes temperature of said catalytic converter, and said predetermined range is set to a smaller range as said temperature of said catalytic converter is lower.
Claim 22
Dependent Claim
41 words
An air-fuel ratio control system according to claim 13, wherein said operating conditions of said engine include deterioration of said catalytic converter, and said predetermined range is set to a smaller range when said catalytic converter is in a deteriorated state.
Claim 23
Dependent Claim
39 words
An air-fuel ratio control system according to claim 13, wherein said operating conditions of said engine include coolant temperature of said engine, and said predetermined range is set to a smaller range as said engine coolant temperature is lower.
Claim 24
Dependent Claim
199 words
An air-fuel ratio control system for an internal combustion engine having a cylinder block, an exhaust passage extending from said cylinder block, and a catalytic converter arranged in said exhaust passage, comprising: an oxygen sensor arranged in said exhaust passage at a location upstream of said catalytic converter; control amount-calculating means for calculating an air-fuel ratio feedback control amount, based on an output from said oxygen sensor; air-fuel ratio control means for controlling an air-fuel ratio of a mixture supplied to said engine based on said air-fuel ratio feedback control amount; first air-fuel ratio-estimating means for estimating an air-fuel ratio of exhaust gases in said exhaust passage at a location immediately downstream of said cylinder block from an amount of variation of said air-fuel ratio feedback control amount relative to an average value of said air-fuel ratio feedback control amount; and second air-fuel ratio-estimating means for estimating an air-fuel ratio of exhaust gases in said exhaust passage at a location immediately upstream of said catalytic converter from an averaged air-fuel ratio obtained by averaging said air-fuel ratio of said exhaust gases at said location immediately downstream of said cylinder block by the use of a predetermined averaging time constant.
Claim 25
Dependent Claim
199 words
An air-fuel ratio control system for an internal combustion engine having a cylinder block, an exhaust passage extending from said cylinder block, and a catalytic converter arranged in said exhaust passage, comprising: an oxygen sensor arranged in said exhaust passage at a location upstream of said catalytic converter; control amount-calculating means for calculating an air-fuel ratio feedback control amount, based on an output from said oxygen sensor; air-fuel ratio control means for controlling an air-fuel ratio of a mixture supplied to said engine based on said air-fuel ratio feedback control amount; first air-fuel ratio-estimating means for estimating an air-fuel ratio of exhaust gases in said exhaust passage at a location immediately downstream of said cylinder block from an amount of variation of said air-fuel ratio feedback control amount relative to an average value of said air-fuel ratio feedback control amount; and second air-fuel ratio-estimating means for estimating an air-fuel ratio of exhaust gases in said exhaust passage at a location immediately upstream of said catalytic converter from an averaged air-fuel ratio obtained by averaging said air-fuel ratio of said exhaust gases at said location immediately downstream of said cylinder block by the use of a predetermined averaging time constant.
Claim 26
Dependent Claim
24 words
An air-fuel ratio control system according to claim 17, wherein said predetermined averaging time constant is determined based on operating conditions of said engine.
Claim 27
Dependent Claim
56 words
An air-fuel ratio control system according to claim 17, including a second oxygen sensor arranged in said exhaust passage at a location downstream of said catalytic converter, and correcting means for correcting said air-fuel ratio of exhaust gases at said location immediately upstream of said catalytic converter, based on an output from said second oxygen sensor.
Claim 28
Dependent Claim
44 words
An air-fuel ratio control system according to claim 17, wherein said air-fuel ratio control means controls the air-fuel ratio of said mixture supplied to said engine, based on said air-fuel ratio of said exhaust gases at said location immediately upstream of said catalytic converter.
Claim 29
Dependent Claim
154 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, and a catalytic converter arranged in said exhaust passage, comprising: an oxygen sensor arranged in said exhaust passage at a location upstream of said catalytic converter; control amount-calculating means for calculating an air-fuel ratio feedback control amount, based on an output from said oxygen sensor; air-fuel ratio control means for controlling an air-fuel ratio of a mixture supplied to said engine, based on said air-fuel ratio-feedback control amount; first averaging means for averaging said air-fuel ratio feedback control amount by a first averaging time constant; second averaging means for averaging said air-fuel ratio feedback control amount by a second averaging time constant; and air-fuel ratio-calculating means for calculating an air-fuel ratio of exhaust gases at a location immediately upstream of said catalytic converter, based on an output from said first averaging means and an output from said second averaging means.
Claim 30
Dependent Claim
154 words
An air-fuel ratio control system for an internal combustion engine having an exhaust passage, and a catalytic converter arranged in said exhaust passage, comprising: an oxygen sensor arranged in said exhaust passage at a location upstream of said catalytic converter; control amount-calculating means for calculating an air-fuel ratio feedback control amount, based on an output from said oxygen sensor; air-fuel ratio control means for controlling an air-fuel ratio of a mixture supplied to said engine, based on said air-fuel ratio-feedback control amount; first averaging means for averaging said air-fuel ratio feedback control amount by a first averaging time constant; second averaging means for averaging said air-fuel ratio feedback control amount by a second averaging time constant; and air-fuel ratio-calculating means for calculating an air-fuel ratio of exhaust gases at a location immediately upstream of said catalytic converter, based on an output from said first averaging means and an output from said second averaging means.
Claim 31
Dependent Claim
65 words
An air-fuel ratio control system according to claim 21, including average value-calculating means for calculating an average value of said air-fuel ratio feedback control amount by the use of said first averaging time constant and wherein said second averaging time constant is determined based on operating conditions of said engine, to an averaging degree smaller than an averaging degree of said first averaging time constant.
Claim 32
Dependent Claim
56 words
An air-fuel ratio control system according to claim 21, including a second oxygen sensor arranged in said exhaust passage at a location downstream of said catalytic converter, and correcting means for correcting said air-fuel ratio of exhaust gases at said location immediately upstream of said catalytic converter, based on an output from said second oxygen sensor.
Claim 33
Dependent Claim
53 words
An air-fuel ratio control system according to claim 21, wherein said air-fuel ratio control means includes control amount-changing means for changing a control amount of said air-fuel ratio of said mixture supplied to said engine, based on said air-fuel ratio of said exhaust gases at said location immediately upstream of said catalytic converter.
Claim 34
Dependent Claim
69 words
An air-fuel ratio control system according to claim 24, wherein said air-fuel ratio control means includes estimating means for estimating an amount of oxygen stored in said catalytic converter, based on said estimated air fuel ratio of exhaust gases at said location immediately upstream of said catalytic converter, and control amount-calculating means for calculating said control amount, based on said estimated amount of oxygen stored in said catalytic converter.
Claim 35
Dependent Claim
147 words
In an exhaust system temperature-estimating device for an internal combustion engine having an exhaust passage, including steady condition temperature-calculating means for calculating a steady condition temperature of said exhaust passage in a steady condition of said engine, based on operating conditions of said engine at least including load on said engine, follow-up speed-calculating means for calculating a follow-up speed of said temperature of said exhaust system relative to said steady condition temperature, and exhaust system temperature-estimating means for estimating temperature of said exhaust system, based on said steady condition temperature and said follow-up speed, the improvement comprising: intake air temperature-detecting means for detecting intake air temperature of said engine; vehicle speed-detecting means for detecting speed of a vehicle on which said engine is installed; and correcting means for correcting said steady condition temperature and/or said follow-up speed, based on said intake air temperature and said vehicle speed.
Claim 36
Dependent Claim
147 words
In an exhaust system temperature-estimating device for an internal combustion engine having an exhaust passage, including steady condition temperature-calculating means for calculating a steady condition temperature of said exhaust passage in a steady condition of said engine, based on operating conditions of said engine at least including load on said engine, follow-up speed-calculating means for calculating a follow-up speed of said temperature of said exhaust system relative to said steady condition temperature, and exhaust system temperature-estimating means for estimating temperature of said exhaust system, based on said steady condition temperature and said follow-up speed, the improvement comprising: intake air temperature-detecting means for detecting intake air temperature of said engine; vehicle speed-detecting means for detecting speed of a vehicle on which said engine is installed; and correcting means for correcting said steady condition temperature and/or said follow-up speed, based on said intake air temperature and said vehicle speed.
Claim 37
Dependent Claim
29 words
An exhaust system temperature-estimating device according to claim 26, including correcting means for correcting said steady condition temperature by an air-fuel ratio of a mixture supplied to said engine.
References Cited (Backward Citations)
JPS5617533A
Cited
US4656829A
Cited
JPS62203965A
Cited
JPS6397848A
Cited
JPH01219340A
Cited
JPH0211841A
Cited
US5077970A
Cited
US5158063A
Cited
US5303168A
Cited
US5462037A
Cited
JPH06193516A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-10-20 | 2001-04-21 | 2001-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-10-20 | 2005-04-21 | 2005-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-10-20 | 2009-04-21 | 2009-10-21 | $7700.00 | Window Closed / Lapsed |