US4664085A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air-fuel ratio control system for an automotive engine
Assignee: Subaru Corp
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Filing: 1985-12-24
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Granted: 1987-05-12
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Expires: 2005-12-24
Abstract
Abstract A control system is provided with a mass airflow sensor for sensing mass of intake air and for producing a mass airflow signal, an engine speed sensor for an engine speed signal proportional to the speed of the engine, and a throttle angle position sensor for producing a throttle angle signal representing the angle of the throttle valve. A first table is provided for storing first coefficients for characteristics of the injector, and a second table is provided for storing second coefficients for characteristics of the mass airflow sensor. Injection pulse width is calculated based on the mass airflow signal, engine speed signal, a read-out first coefficient and a read-out second coefficient which are dependent on the mass airflow-signal, the engine speed signal and the throttle angle signal.
Inventors
- 👤 Ryuji Kataoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:18
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/24; F02D41/2406; F02D41/2409; F02D41/2422; F02D41/30; F02D41/3005; F02D2200/00; F02D2200/02; F02D2200/06; F02D2200/0614; F02D2250/00; F02D2250/16; F02D41/02; F02D41/18; F02D41/187
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
167 words
An air-fuel ratio control system for an automotive engine having at least one fuel injector operating by an injection pulse and a throttle valve, the system comprising: a mass airflow sensor for sensing mass of intake air and for producing a mass airflow signal; an engine speed sensor for producing an engine speed signal proportional to the speed of the engine; a throttle angle position sensor for producing a throttle angle signal representing the angle of the throttle valve; a first table storing first coefficients for correcting deviation of air-fuel ratio which is caused by characteristics of the injector; a second table storing second coefficients for correcting deviation of the air-fuel ratio which is caused by characteristics of the mass airflow sensor for flow-back air; means for calculating the injection pulse width based on the mass airflow signal, engine speed signal, a read-out first coefficient and a read-out second coefficient respectively, said coefficients being dependent on the mass airflow signal, engine speed signal and throttle angle signal.
Claim 2
Dependent Claim
167 words
An air-fuel ratio control system for an automotive engine having at least one fuel injector operating by an injection pulse and a throttle valve, the system comprising: a mass airflow sensor for sensing mass of intake air and for producing a mass airflow signal; an engine speed sensor for producing an engine speed signal proportional to the speed of the engine; a throttle angle position sensor for producing a throttle angle signal representing the angle of the throttle valve; a first table storing first coefficients for correcting deviation of air-fuel ratio which is caused by characteristics of the injector; a second table storing second coefficients for correcting deviation of the air-fuel ratio which is caused by characteristics of the mass airflow sensor for flow-back air; means for calculating the injection pulse width based on the mass airflow signal, engine speed signal, a read-out first coefficient and a read-out second coefficient respectively, said coefficients being dependent on the mass airflow signal, engine speed signal and throttle angle signal.
Claim 3
Dependent Claim
31 words
An air-fuel ratio control system according to claim 1, wherein said means calculates said injection pulse width by using said first and second coefficients at any angle of the throttle valve.
Claim 4
Dependent Claim
24 words
An air-fuel ratio control system according to claim 2, wherein said means calculates said injection pulse width by adding said first and second coefficients.
Claim 5
Dependent Claim
65 words
An air-fuel ratio control system according to claim 1, wherein said means calculates said injection pulse width by using said first coefficient but not said second coefficient when the angle of the throttle valve is less than a predetermined value, and respectively, by using said second coefficient but not said first coefficient when the angle of the throttle valve is greater than said predetermined value.
Claim 6
Dependent Claim
27 words
The air-fuel ratio control system according to claim 1 wherein the second coefficient is read out when the throttle angle signal is larger than a predetermined angle.
Claim 7
Dependent Claim
59 words
The air-fuel ratio control system according to claim 1 wherein the first coefficient is read out based on a basic injection pulse width which is obtained by dividing the airflow signal with the engine speed signal and on the engine speed signal, and the second coefficient is read out based on the engine speed signal and throttle angle signal.
References Cited (Backward Citations)
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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) | 1990-05-11 | 1990-11-10 | 1991-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-11 | 1994-11-10 | 1995-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-11 | 1998-11-10 | 1999-05-12 | $7700.00 | Window Closed / Lapsed |