Knocking control method and apparatus for internal combustion engine
First Claim
1. A method of controlling knocking in an internal combustion engine, comprising the steps of:
- generating a vibration level periodically at a predetermined time interval on the basis of an output signal of a knocking sensor installed for detecting vibrations of said engine;
making a decision as to whether or not said vibration level exceeds a predetermined value;
averaging said vibration level in accordance with a first predetermined constant defining a first vibration level significance ratio to provide a first mean value unless said vibration level exceeds said predetermined value;
averaging said vibration level in accordance with a second predetermined constant defining a second vibration level significance ratio which is less than said first predetermined significance ratio to provide a second mean value if said vibration level exceeds said predetermined value;
generating a threshold level, which is referred to upon making a decision as to the occurrence of knocking, on the basis of either one of said first and second mean values;
comparing said vibration level with said threshold level to determine whether there is knocking in the engine; and
controlling an engine control parameter so as to suppress engine knocking when said vibration level exceeds said threshold level.
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Accused Products
Abstract
A method and an apparatus for suppressing knocking in an internal combustion engine are disclosed therein. Vibrations of the engine are detected periodically by a knocking sensor installed on the engine. Decision is made as to whether or not the vibration level as detected exceeds a predetermined value. In dependence on the result of the decision, the vibration level is averaged with a first or a second significance ratio which differ from each other and which are previously determined in consideration of variations in the vibration level brought about by degradation of the knocking sensor in the course of time lapse or by an engine operating state. A mean value obtained through the averaging processing is utilized as a basis for determining a threshold level for comparison with the vibration level for making decision as to the occurence of knocking. Upon detection of knocking, a retarded ignition control signal for retarding the ignition timing of the engine is generated to thereby suppress the occurrence of knocking. Because the threshold level reflects variations in the vibration level over time or variations in the engine operating state, knocking can be identified with improved reliability. Major portions of the apparatus can be implemented by using a microprocessor, whereby hardware requirement and expenditure can be mitigated significantly.
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Citations
22 Claims
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1. A method of controlling knocking in an internal combustion engine, comprising the steps of:
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generating a vibration level periodically at a predetermined time interval on the basis of an output signal of a knocking sensor installed for detecting vibrations of said engine; making a decision as to whether or not said vibration level exceeds a predetermined value; averaging said vibration level in accordance with a first predetermined constant defining a first vibration level significance ratio to provide a first mean value unless said vibration level exceeds said predetermined value; averaging said vibration level in accordance with a second predetermined constant defining a second vibration level significance ratio which is less than said first predetermined significance ratio to provide a second mean value if said vibration level exceeds said predetermined value; generating a threshold level, which is referred to upon making a decision as to the occurrence of knocking, on the basis of either one of said first and second mean values; comparing said vibration level with said threshold level to determine whether there is knocking in the engine; and controlling an engine control parameter so as to suppress engine knocking when said vibration level exceeds said threshold level. - View Dependent Claims (2, 3)
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4. A knocking control apparatus for suppressing knocking in an internal combustion engine, comprising:
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a knocking sensor for detecting vibrations of said engine and generating a corresponding output signal; a vibration level generator operatively connected to receive the output signal of said knocking sensor for generating a vibration level representing the magnitude of said engine vibrations on the basis of the output signal of said knocking sensor at every predetermined time interval; vibration level determining means operatively connected to said vibration level generator for making a decision as to whether or not said vibration level exceeds a predetermined value; vibration level averaging means operatively connected to said vibration level generator and said vibration level determining means, respectively, said vibration level averaging means being responsive to the output of said vibration level determining means such that it averages said vibration level in accordance with a first predetermined constant defining a first vibration level significance ratio to provide a first means value unless said vibration level exceeds said predetermined value, and with a second predetermined constant defining a second vibration level significance ratio, which is smaller than said first significance ratio, to provide a second mean value if said vibration level exceeds said predetermined value; calculating means operatively connected to said vibration level averaging means for generating a threshold level, which is referred to upon making a decision as to the occurrence of knocking, on the basis of either one of said first and second mean values; knocking identification means operatively connected to receive outputs of said vibration level generator and said calculating means for comparing said vibration level with said threshold level so that it generates a knocking identification signal if said vibration level exceeds said threshold level; and knocking control means responsive to the knocking identification signal from said knocking identification means for controlling an engine control parameter so that said knocking can - View Dependent Claims (5, 6, 7, 8, 9, 10)
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11. A method of controlling knocking in an internal combustion engine, comprising the steps of:
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generating a vibration level periodically at a predetermined time interval on the basis of an output signal of a knocking sensor installed for detecting vibrations of said internal combustion engine; making a decision as to whether or not said engine is in a transitional operating state; averaging said vibration level in accordance with a first predetermined constant defining a first vibration level significance ratio to provide a first mean value unless said engine is in a transitional operating state; averaging said vibration level in accordance with a second predetermined constant defining a second vibration level significance ratio which is greater than said first predetermined significance ratio to provide a second mean value if said engine is in a transitional operating state; generating a threshold level, which is referred to upon making a decision as to the occurrence of knocking, on the basis of either one of the first and second mean values; comparing said vibration level with said threshold level to determine whether there is knocking in the engine; and controlling an engine control parameter so as to suppress engine knocking when said vibration level exceeds said threshold level. - View Dependent Claims (12, 13, 14)
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15. A knocking control apparatus for suppressing knocking in an internal combustion engine, comprising:
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a knocking sensor for detecting vibrations of said engine and generating a corresponding output signal; a vibration level generator operatively connected to receive the output signal of said knocking sensor for generating a vibration level representing the magnitude of said engine vibrations on the basis of the output signal of said knocking sensor at every predetermined time interval; transitional state determining means operatively connected to said vibration level generator for making a decision as to whether or not said engine is in a transitional state; vibration level averaging means operatively connected to said vibration level generator and said transitional state determining means, respectively, said vibration level averaging means being responsive to an output of said transitional state determining means such that it averages said vibration level in accordance with a first predetermined constant defining a first vibration level significance ratio to provide a first mean value unless said engine is in a transitional operating state, and in accordance with a second predetermined constant defining a second vibration level significance ratio, which is greater than said first significance ratio, to provide a second mean value if said engine is in a transitional operating state; calculating means operatively connected to said vibration level averaging means for generating a threshold level, which is referred to upon making a decision as to the occurrence of knocking, on the basis of either one of said first and second mean values; knocking identification means operatively connected to receive outputs of said vibration level generator and said calculating means for comparing said vibration level with said threshold level so that it generates a knocking identification signal if said vibration level exceeds said threshold level; and knocking control means responsive to the knocking identification signal from said knocking identification means for controlling an engine control parameter so that said knocking can be suppressed. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification