System and method for controlling a mixture ratio of air-fuel mixture supplied to an internal combustion engine
First Claim
1. A system for determining and controlling the mixture ratio of an air-fuel mixture supplied to an internal combustion engine, comprising:
- (a) first means for detecting an internal pressure of an engine cylinder;
(b) second means for deriving a maximum value of the internal cylinder pressure detected by the first means for each combustion stroke of the engine cylinder and for estimating the rich-side air-fuel mixture ratio and lean-side air-fuel mixture ratio from the derived maximum value of the internal cylinder pressure;
(c) third means for detecting various operating conditions of the engine and a vehicle in which the engine is mounted affecting a change in the air-fuel mixture ratio except the first means and outputting first signals indicative of the individual operating conditions;
(d) fourth means for processing a weighting calculation for the first signals using a weight vector and outputting a second signal indicative of the result of the weighting calculation, the second signal being used to determine the rich or lean air-fuel mixture ratio;
(e) fifth means for comparing the level of the second signal with a reference signal level so as to determine whether the air-fuel mixture ratio deviates from the rich-side or lean-side with respect to a target air-fuel mixture ratio;
(f) sixth means for ascertaining the air-fuel mixture ratio from the rich-side or lean-side air fuel mixture ratio estimated by the second means on the basis of the determination result by the fifth means;
(g) seventh means for controlling the mixture ratio of air-fuel fuel mixture supplied to the engine on the basis of the air-fuel mixture ratio ascertained by the sixth means;
(h) eighth means for determining the correctness or incorrectness of the determination result by the fifth means according to the air-fuel mixture controlled by the seventh means; and
(i) ninth means for correcting the weight vector in the fourth means on the basis of the result of determination by the seventh means in a direction toward which a percentage of the correct determination is increased.
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Abstract
A system and method for determining and controlling the mixture ratio of an air-fuel mixture supplied to an internal combustion engine in which the air-fuel mixture ratio is estimated from a maximum internal pressure of an engine cylinder. The estimated air-fuel mixture ratio is then positively ascertained on the basis of a determination result derived by a weighting processing calculation of input signals indicating various engine and vehicle operating conditions affecting the change in the air-fuel mixture ratio using a weight vector with a reference signal. The air-fuel mixture is controlled on the basis of the ascertained air-fuel mixture ratio. Furthermore, each parameter of the weight vector is learned and corrected in a direction toward which a correct percentage of the determination of the rich-side or lean-side air-fuel mixture ratio by the weight calculation is increased.
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Citations
18 Claims
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1. A system for determining and controlling the mixture ratio of an air-fuel mixture supplied to an internal combustion engine, comprising:
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(a) first means for detecting an internal pressure of an engine cylinder; (b) second means for deriving a maximum value of the internal cylinder pressure detected by the first means for each combustion stroke of the engine cylinder and for estimating the rich-side air-fuel mixture ratio and lean-side air-fuel mixture ratio from the derived maximum value of the internal cylinder pressure; (c) third means for detecting various operating conditions of the engine and a vehicle in which the engine is mounted affecting a change in the air-fuel mixture ratio except the first means and outputting first signals indicative of the individual operating conditions; (d) fourth means for processing a weighting calculation for the first signals using a weight vector and outputting a second signal indicative of the result of the weighting calculation, the second signal being used to determine the rich or lean air-fuel mixture ratio; (e) fifth means for comparing the level of the second signal with a reference signal level so as to determine whether the air-fuel mixture ratio deviates from the rich-side or lean-side with respect to a target air-fuel mixture ratio; (f) sixth means for ascertaining the air-fuel mixture ratio from the rich-side or lean-side air fuel mixture ratio estimated by the second means on the basis of the determination result by the fifth means; (g) seventh means for controlling the mixture ratio of air-fuel fuel mixture supplied to the engine on the basis of the air-fuel mixture ratio ascertained by the sixth means; (h) eighth means for determining the correctness or incorrectness of the determination result by the fifth means according to the air-fuel mixture controlled by the seventh means; and (i) ninth means for correcting the weight vector in the fourth means on the basis of the result of determination by the seventh means in a direction toward which a percentage of the correct determination is increased. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for determining and controlling a mixture ratio of air-fuel mixture supplied to an internal combustion engine, comprising the steps of:
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(a) detecting an internal pressure of an engine cylinder; (b) second means for deriving a maximum value of the internal cylinder pressure detected in the step (a) for each combustion stroke of the engine cylinder and estimating rich-side air-fuel mixture ratio and lean-side air-fuel mixture ratio from the derived maximum value of the internal cylinder pressure; (c) detecting various operating conditions of the engine and a vehicle in which the engine is mounted affecting a change in the air-fuel mixture ratio except that detected in the step (a) and outputting the first signals indicative of the individual operating conditions; (d) calculating a weighting processing for the first signals using a weight vector and outputting a second signal indicative of the result of the weighting processing calculation, the second signal being used to determine the rich or lean side air-fuel mixture ratio; (e) comparing the level of the second signal with a reference signal level so as to determine whether the air-fuel mixture ratio is deviates from the rich-side or lean-side with respect to a target fuel mixture ratio; (f) ascertaining the air-fuel mixture ratio from either the rich-side or lean-side air-fuel mixture ratio estimated in the step (b) on the basis of the determination result in step (e); (g) controlling the mixture ratio of air-fuel mixture supplied to the engine on the basis of the mixture ratio ascertained in step (f); (h) determining a correctness or incorrectness of the determination result of step (e) according to the air-fuel mixture ratio controlled in step (g); and (i) correcting the weight vector used in step (d) on the basis of result of determination in the step (h) in a direction toward which a percentage of the correct determination in step (e) is increased.
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Specification