Abstract: An engine ECU executes operations including: extracting vibration intensities of a plurality of frequency bands from vibration detected by a knock sensor, multiplying the extracted vibration intensity of each frequency band by a weight coefficient and adding the results in correspondence with crank angles to calculate integrated values of every five degrees; calculating a coefficient of correlation based on a result of comparison between a vibration waveform of a frequency band and a knock waveform model prepared in advance; calculating a knock intensity; determining occurrence of knocking in accordance with the calculated coefficient of correlation and the knock intensity; and determining no occurrence of knocking in accordance with the calculated coefficient of correlation and the knock intensity.

Abstract: An engine ECU executes a program including the steps of: calculating a coefficient of correlation K in accordance with a result of comparing a waveform of a vibration of a frequency band including a resonance frequency of an engine with a knock waveform model previously created as a waveform of a vibration caused when the engine knocks; calculating a knock intensity N from an intensity of a vibration of a frequency band excluding the resonance frequency of the engine; if knock intensity N is larger than a reference value and coefficient of correlation K is larger than a threshold value, determining that the engine knocks; and if knock intensity N is smaller than the reference value and/or coefficient of correlation K is smaller than the threshold value, determining that the engine does not knock.

Abstract: Out of synthesized waveforms of vibrations in a first frequency band A to a third frequency band C, a knock magnitude N is calculated by using a portion ? having an integrated value greater than a reference magnitude in a knock region but not using a portion having an integrated value greater than the reference magnitude out of the knock region (i.e., a region obtained by excluding the knock region from a knock detecting gate). In a case where knock magnitude N is greater than a determination value V(KX), it is determined that knocking occurs. In contrast, in a case where knock magnitude N is not greater than determination value V(KX), it is determined that no knocking occurs.

Abstract: An engine ECU executes a program including a step of setting a search range of the crank angle of a peak value P that is the largest integrated value in a vibration waveform of an engine detected by calculating integrated values that are integrals of output voltage values of a knock sensor for every five degrees of a crank angle such that the search range may include the crank angle increasing with increase in engine speed NE, and a step of detecting the crank angle of the largest integrated value in the search range, and setting the detected crank angle as the crank angle of peak value P in the vibration waveform. At the crank angle based on the crank angle of peak value P, the vibration waveform is compared with a knock waveform model.

Abstract: An engine ECU executes a program that includes the steps of: calculating (S204) a median value V(50) and a standard deviation s based on a calculated magnitude value LOG(V); and subtracting (S206) a product of the standard deviation s and a coefficient U(3) from the median value V(50) to calculate BGL. Knocking determination is carried out by comparing a knock magnitude N calculated by dividing the magnitude value LOG(P) by the BGL with a predetermined determination value V(VK). Based on the knocking determination result, ignition timing of the engine is controlled.

Abstract: An engine ECU executes a program including the steps of: calculating an absolute value ?S(I) of the deviation of the vibration waveform detected by a knock sensor and a knock waveform model from each other at each crank angle; when ?S(I) greater than threshold value ?S(0) is present and the number of ?S(I) greater than threshold value ?S(0) is equal to or smaller than Q(1), correcting the vibration waveform; calculating a correlation coefficient K which is a value related to the deviation of the corrected vibration waveform and the knock waveform model from each other; and when the number of ?S(I) greater than threshold value ?S(0) is greater than predetermined number Q(1), calculating the correlation coefficient K without correcting the vibration waveform. Based on the correlation coefficient K, whether knocking is present or absent is determined.

Abstract: An engine ECU executes a program including calculating a correlation coefficient by dividing the sum of respective absolute values, which are each a difference between a magnitude in an engine vibration waveform and a magnitude in a knock waveform model for every crank angle, by an area corresponding to magnitudes equal to or larger than a positive reference value in the knock waveform model, and determining whether or not knocking has occurred based on the correlation coefficient.

Abstract: An engine ECU executes a program including the steps of: calculating an absolute value ?S(I) of the deviation of the vibration waveform detected by a knock sensor and a knock waveform model from each other at each crank angle; when ?S(I) greater than threshold value ?S(0) is present and the number of ?S(I) greater than threshold value ?S(0) is equal to or smaller than Q(1), correcting the vibration waveform; calculating a correlation coefficient K which is a value related to the deviation of the corrected vibration waveform and the knock waveform model from each other; and when the number of ?S(I) greater than threshold value ?S(0) is greater than predetermined number Q(1), calculating the correlation coefficient K without correcting the vibration waveform. Based on the correlation coefficient K, whether knocking is present or absent is determined.

Abstract: An engine ECU executes a program including the steps of: detecting a magnitude of vibration of an engine (S 102); detecting a vibration waveform of the engine based on the magnitude (S 104); calculating a correlation coefficient K, in the case where the engine speed NE is smaller than a threshold value NE (1), using the sum of values each determined by subtracting a positive reference value from a magnitude of a knock waveform model, as an area S of the knock waveform model and, calculating the correlation coefficient K, in the case where the engine speed NE is not smaller than the threshold value NE (1), using the area S of the whole knock waveform model (S114); and determining whether or not knocking has occurred using the correlation coefficient K (S 120, S 124). The correlation coefficient K is calculated by dividing by the area S the sum of differences that are each the difference between the magnitude on the vibration waveform and the magnitude on the knock waveform model.

Abstract: An engine ECU executes a program including: the step of increasing a determination value by a correction amount if the number of knock intensities not lower than the determination value is not smaller than a threshold value among knock intensities of a plurality of predetermined number of continuous ignition cycles; and the step of increasing the determination value by a correction amount if the number of knock intensities not smaller than the determination value is not smaller than a threshold value, among knock intensities of a plurality of ignition cycles satisfying the condition that a coefficient of correlation calculated by comparing a vibration waveform and a knock waveform model is not smaller than a threshold value, of the knock intensities of a plurality of predetermined continuous ignition cycles.

Abstract: An engine ECU executes: calculating 15-degrees integrated value integrating vibration intensity for each of six crank angle ranges; detecting an amount of change in the 15-degrees integrated value between ignition cycles; specifying two ranges having larger amounts of change; specifying a crank angle having intensity larger than that of a neighboring crank angle in a search range determined to be the same as the specified ranges; calculating a coefficient of correlation K corresponding to a difference between a vibration waveform and a knock waveform model while the specified crank angle is matched with a timing at which intensity peaks in the knock waveform model; and, if the coefficient of correlation K is larger than a threshold value K(0), determining that knock has occurred.

Abstract: An engine ECU executes a program including the steps of: calculating a correlation coefficient K based on the result of comparing a vibration waveform of an engine and a knock waveform model stored previously; calculating a magnitude value LOG(V) from the magnitude V detected based on a signal transmitted from a knock sensor; creating frequency distribution of magnitude values LOG(V) by using magnitude values LOG(V) in an ignition cycle in which the correlation coefficient K larger than a threshold K(1) is calculated; and counting knock proportion KC by using the created frequency distribution. If the vibration waveform includes a waveform of vibration of noise components, the correlation coefficient K is calculated to be smaller comparing with a case of not including it.

Abstract: An engine ECU includes a bandpass filter (1) extracting only vibrations at a first frequency band A, a bandpass filter (2) extracting only vibrations at a second frequency band B, a bandpass filter (3) extracting only vibrations at a third frequency band C, and a bandpass filter (4) extracting only vibrations at a fourth frequency band D including the first to third frequency bands A-C. The engine ECU determines whether knocking occurred or not based on a vibration waveform of the fourth frequency band D and a peak value in magnitude of vibrations in a synthesized waveform of the first to third frequency bands.

Abstract: An engine ECU executes a program including: determining whether or not a condition for stopping knocking determination is satisfied; setting a flag of stopping correction of a determination value to “ON”; calculating a knock determination level based on the extracted magnitude value; and when the correction stop flag is not “ON”, decreasing or increasing the determination value in accordance with a knock proportion KC that is a proportion of magnitude values greater than the knock determination level. The knock determination level is calculated even when the correction stop flag is “ON”.

Abstract: An engine ECU executes a program including a step of, when it has temporarily been determined that knocking had occurred because of the presence of an integrated value greater than a product of the reference magnitude and coefficient Y among the integrated values of vibration in fourth frequency band D that includes first to third frequency bands A to C, calculating knock magnitude N using the integrated values in the synthesized waveform of first to third frequency bands A to C and correlation coefficient K calculated from a vibration waveform of fourth frequency band D. Based on a comparison between knock magnitude N and determination value V(KX), whether or not knocking has occurred is determined. If there is no integrated value greater than a product of the reference magnitude and coefficient Y, it is determined that knocking has not occurred.

Abstract: An engine ECU 200 includes a bandpass filter (1), a bandpass filter (2), and a bandpass filter (3). The bandpass filter (1) extracts only vibrations at a first frequency band A from the vibrations detected by a knock sensor. The bandpass filter (2) extracts only vibrations at a second frequency band B from the vibrations detected by the knock sensor. The bandpass filter (3) extracts only vibrations at a third frequency band C from the vibrations detected by the knock sensor. The first to third frequency bands A-C are identical in bandwidth. The engine ECU calculates a peak value in magnitude of vibrations in a synthesized waveform of these frequency bands, and determines whether knocking occurred or not based on the peak value.

Abstract: An engine ECU executes a program including a step of, when an absolute value of a difference between a determination value V(KX) used for determining presence or absence of knocking and a maximum value V(MAX) of magnitude value LOG(V), which is obtained by logarithmically converting a magnitude V detected based on a signal sent from a knock sensor, is greater than the product of a standard deviation ? and a coefficient U(3) in a frequency distribution of magnitude values LOG(V) for N cycle(s), setting a value obtained by adding the product of the standard deviation ? and the coefficient U(3) to the maximum value V(MAX) of the magnitude value LOG(V) as the determination value V(KX).

Abstract: An engine ECU executes a program including: a step (S310) of multiplying a correction amount of a determination value V(KX) by Q, when deviation L between an approximation value V(R), which is an average value of determination values V(KX) corrected according to the occurrence frequency of knocking, and an approximation value V(R?1) previously calculated is greater than a predetermined value (NO in S306) or when the number of times where deviation L is determined to be smaller than a predetermined value is smaller than a predetermined number of times (NO in S308); and a step (S312) of multiplying the correction amount of the determination value V(KX) by 1/P, when the number of times where the deviation L is determined to be smaller than a predetermined value is greater than a predetermined number of times (YES in S308). By comparing the determination value V(KX) and knock magnitude, determination of knocking is made, and ignition timing is advanced or retarded.

Abstract: A knocking judgement method for an internal combustion engine, in which an engine ECU executes a program judging whether or not such ones of integrated values calculated by integrating the output of a knock sensor at every five degrees of a crank angle are larger than a tentative knock judgement value, in vibrations of a fourth frequency band containing the resonance frequency of the engine, tentatively judging that a knocking has occurred, in case the integrated value larger than the tentative knock judgement value is a predetermined number or more, and judging that no knocking has occurred, in case the integrated value larger than the tentative knock judgement value is not more than the predetermined number.

Abstract: An engine ECU executes a program including the steps of: calculating a coefficient of correlation K in accordance with a result of comparing a waveform of a vibration of a frequency band including a resonance frequency of an engine with a knock waveform model previously created as a waveform of a vibration caused when the engine knocks (S112); calculating a knock intensity N from an intensity of a vibration of a frequency band excluding the resonance frequency of the engine (S114); if knock intensity N is larger than a reference value and coefficient of correlation K is larger than a threshold value (YES at S116), determining that the engine knocks (S118); and if knock intensity N is smaller than the reference value and/or coefficient of correlation K is smaller than the threshold value, determining that the engine does not knock (S122).