Claims
- 1. A method of learn-controlling an air-fuel ratio for an internal combustion engine, comprising the steps of:
- (a) calculating a basic fuel injection duration TP based on an intake-pipe pressure and a rotational speed of the engine;
- (b) obtaining a factor of air-fuel ratio feedback correction FAF for allowing a fuel injection duration TAU to perform a proportional-plus-integral action, based on an output of an oxygen sensor for detecting a residual oxygen concentration in an exhaust gas;
- (c) calculating a mean value FAFAV of said factor of air-fuel ratio feedback correction FAF;
- (d) increasing an idling correction value TAUG during idling and when said mean value FAFAV exceeds an upper-limit value of a predetermined range including the value of said factor of air-fuel ratio feedback correction corresponding to a target air-fuel ratio, and decreasing said idling correction value TAUG during idling and when said mean value FAFAV is less than the lower-limit value of said predetermined range;
- (e) increasing an off-idling correction value KG during operation of the engine other than idling and when said mean value FAFAV exceeds the upper-limit value of said predetermined range, and decreasing said off-idling correction value KG during operation of the engine other than idling and when said mean value FAFAV is less than the lower-limit value of said predetermined range; and
- (f) calculating the fuel injection duration TAU through the following equation, thereby to control the air-fuel ratio:
- TAU=(TP+TAUG).multidot.KG.multidot.FAF.multidot.F(x)+.tau..sub.v
- where F(x) is a factor of increasing fuel in quantity, and .tau..sub.v is a non-effective injection duration.
- 2. A method of learn-controlling an air-fuel ratio for an internal combustion engine, comprising the steps of:
- (a) calculating a basic fuel injection duration based on an engine load and a rotational speed of the engine;
- (b) obtaining a factor of air-fuel ratio feedback correction for allowing a fuel injection duration to perform a proportional-plus-integral action, based on an output of an oxygen sensor for detecting an residual oxygen concentration in an exhaust gas;
- (c) calculating a mean value of said factor of air-fuel ratio feedback correction;
- (d) varying a correction value by learning so that said mean value takes a value within a predetermined range centered at a predetermined value corresponding to a target air-fuel ratio; and
- (e) obtaining the fuel injection duration based on said basic fuel injection duration, said factor of air-fuel ratio feedback correction and said correction value, thereby, to control the air-fuel ratio.
- 3. A method of learn-controlling an air-fuel ratio for an internal combustion engine according to claim 1, wherein said correction value includes an idling correction value varied by learning during idling, and an off-idling correction value varied by learning during operation of the engine other than idling and when an throttle valve opening is less than a predetermined value.
- 4. A method of learn-controlling an air-fuel ratio for an internal combustion engine according to claim 1, wherein said correction value includes an idling correction value varied by learning during idling, and an off-idling correction value varied by learning during operation of the engine other than idling.
- 5. A method of learn-controlling an air-fuel ratio for an internal combustion engine according to claim 2, wherein said off-idling correction value includes a plurality of values determined in accordance with an intake-pipe pressure.
- 6. A method of learn-controlling an air-fuel ratio for an internal combustion engine, comprising the steps of:
- (a) calculating a basic fuel injection duration TP based on an intake-pipe pressure and a rotational speed of the engine;
- (b) obtaining a factor of air-fuel ratio feedback correction FAF for allowing a fuel injection duration TAU to perform a proportional-plus-integral action, based on an output of an oxygen sensor for detecting a residual oxygen concentration in an exhaust gas;
- (c) calculating a mean value FAFAV of said factor of air-fuel ratio feedback correction FAF;
- (d) varying an idling correction value TAUG by learning, during idling, so that said mean value FAFAV takes a value within a predetermined range centered at a predetermined value corresponding to a target air-fuel ratio;
- (e) varying an off-idling correction value KG by learning, during operation of the engine other than idling, so that said mean value FAFAV takes a value within the predetermined range centered at the predetermined value corresponding to the target air-fuel ratio; and
- (f) calculating the fuel injection duration TAU through the following equation, thereby to control the air-fuel ratio:
- TAU=(TP+TAUG).multidot.KG.multidot.FAF.multidot.F(x)+.tau..sub.v
- where F(x) is a factor of increasing fuel in quantity, and .tau..sub.v is a non-effective injection duration.
- 7. A method of learn-controlling an air-fuel ratio for an internal combustion engine according to claim 5, wherein said off-idling correction value includes a plurality of values determined in accordance with the intake-pipe pressure, which are varied by learning in accordance with the intake-pipe pressure.
- 8. A method of learn-controlling an air-fuel ratio for an internal combustion engine according to claim 5, wherein said predetermined value corresponding to the target air-fuel ratio is 1.
- 9. A method of learn-controlling an air-fuel ratio for an internal combustion engine according to claim 5, wherein said off-idling correction value KG is varied by learning during operation of the engine other than idling and when a throttle valve opening is less than a predetermined value.
Priority Claims (1)
Number |
Date |
Country |
Kind |
56-8202 |
Jan 1981 |
JPX |
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Parent Case Info
This is a continuation-in-part of the application Ser. No. 316,038 filed Oct. 28, 1981, now abandoned.
US Referenced Citations (5)
Continuation in Parts (1)
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Number |
Date |
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Parent |
316038 |
Oct 1981 |
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