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).

Abstract: A 90° integrated value calculating unit of an engine ECU calculates a 90° integrated value obtained by integrating a magnitude. A calculating unit calculates a knock magnitude by dividing 90° integrated value by a BGL. A value obtained by subtracting a standard deviation ? from a median value of 90° integrated value is determined as the BGL. An ignition timing control unit controls the ignition timing depending on whether knock magnitude is equal to or larger than a determination value. A median value calculating unit calculates median value of 90° integrated value. A standard deviation calculating unit calculates standard deviation of 90° integrated value. A first stop unit stops updating of median value and standard deviation when 90° integrated value is smaller than a first threshold value or is equal to or larger than a second threshold value.

Abstract: An engine ECU executes a program including the steps of: determining that the condition that there is a possibility of occurrence of knocking is satisfied, based on the result of comparison between a vibration waveform of an engine and a knock waveform model; calculating a 40CA integrated value by integrating magnitudes of vibration occurring in the engine for a range of crank angle of 40°; calculating a knock magnitude N by dividing the 40CA integrated value by a BGL; determining that knocking has occurred when the knock magnitude N is larger than a determination value V(KX); and determining that knocking has not occurred when the knock magnitude N is smaller than the determination value V(KX).

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: 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 calculating intensity values LOG(V), a step of detecting vibration waveforms, a step of calculating a correlation coefficient K based on vibration waveforms, a step of preparing frequency distribution of intensity values LOG(V) smaller than a threshold V(1) and intensity values LOG(V) in an ignition cycle where correlation coefficient K is larger than a threshold K(1), a step of calculating a knock determination level V(KD) based on a median V(50) and a standard deviation ? of intensity values LOG(V), and a step of counting the number of intensity values LOG(V) larger than knock determination level V(KD) as the number of times that knocking has occurred.

Abstract: An engine ECU executes a program including the steps of: calculating a magnitude value LOG(V) by logarithmically converting a magnitude V of vibration occurring in an engine, calculating a median V(50) and a standard deviation ? of magnitude values LOG(V); and setting, to the product of the standard deviation ? and a factor A, a first upper limit of a determination value V(KX) that is to be compared with a knock magnitude N for determining whether or not knocking has occurred, and setting a first lower limit of the determination value V(KX) to the product of the standard deviation ? and a factor B.

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 including a step of calculating intensity values LOG(V) based on signals transmitted from a knock sensor; a step of deciding a maximum value V(MAX) in frequency distribution of intensity values LOG(V) for N cycles (N is a natural number); a step of calculating a knock determination level V(KD) based on the frequency distribution; a step of, when the knock determination level V(KD) is smaller than the maximum value V(MAX), removing V(MAX) from the frequency distribution; and a step of counting the total frequency of removed maximum values V(MAX) as knock occupancy KC. Maximum values V(MAX) are removed until the knock determination level V(KD) and the maximum value V(MAX) coincide, and the knock determination level V(KD) is recalculated.

Abstract: An engine ECU executes a program including: the step (S222) of increasing a determination value V(J) by a correction amount A(3) if the number of knock intensities N not lower than the determination value V(J) is not smaller than a threshold value B(1) (YES at S220) among knock intensities N of a plurality of predetermined number of continuous ignition cycles; and the step (S232) of increasing the determination value V(J) by a correction amount A(5) if the number of knock intensities N not smaller than the determination value V(J) is not smaller than a threshold value B(3) (YES at S230), among knock intensities N of a plurality of ignition cycles satisfying the condition that a coefficient of correlation K calculated by comparing a vibration waveform and a knock waveform model is not smaller than a threshold value K(1), of the knock intensities of a plurality of predetermined continuous ignition cycles.

Abstract: An engine ECU executes a program including the steps of: detecting a vibration corresponding to a first radial resonance mode by using a band-pass filter, from vibrations sensed by an in-cylinder pressure sensor provided at an upper central portion of the cylinder; calculating knock intensity N based on a result of comparison between the detected waveform and a knock waveform model prepared in advance as a vibration waveform when knocking occurs; determining that knocking occurred when the knock intensity N is larger than a predetermined reference value; and determining that knocking has not occurred when the knock intensity N is not larger than the predetermined reference value.

Abstract: An engine ECU executes a program including a step of calculating a correlation coefficient K representing a degree of agreement between a vibration waveform and a knock waveform model, a step of calculating a knock magnitude N by dividing a peak value P of magnitude in the vibration waveform by BGL, a step of determining whether knocking has occurred based on a combination of the correlation coefficient K and the knock magnitude N, in such a manner as to determine that knocking has not occurred in at least one of the case where the correlation coefficient K is smaller than a threshold value K(1) and the case where the knock magnitude N is smaller than a threshold value N(1), and a step of retarding ignition timing by a retarding amount corresponding to the combination of the correlation coefficient K and the knock magnitude N, if knocking has occurred.

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 executes a program including a step of calculating intensity values LOG(V) based on signals transmitted from a knock sensor; a step of deciding a maximum value V(MAX) in frequency distribution of intensity values LOG(V) for N cycles (N is a natural number); a step of calculating a knock determination level V(KD) based on the frequency distribution; a step of, when the knock determination level V(KD) is smaller than the maximum value V(MAX), removing V(MAX) from the frequency distribution; and a step of counting the total frequency of removed maximum values V(MAX) as knock occupancy KC. Maximum values V(MAX) are removed until the knock determination level V(KD) and the maximum value V(MAX) coincide, and the knock determination level V(KD) is recalculated.

Abstract: An engine ECU executes a program including the steps of: detecting a vibration corresponding to a first radial resonance mode by using a band-pass filter, from vibrations sensed by an in-cylinder pressure sensor provided at an upper central portion of the cylinder; calculating knock intensity N based on a result of comparison between the detected waveform and a knock waveform model prepared in advance as a vibration waveform when knocking occurs; determining that knocking occurred when the knock intensity N is larger than a predetermined reference value; and determining that knocking has not occurred when the knock intensity N is not larger than the predetermined reference value.

Abstract: An engine ECU executes a program including a step of, when an absolute value of a difference between median value V(50) of magnitude values LOG(V), which is obtained by logarithmically converting a magnitude V detected based on a signal sent from a knock sensor, and a determination value V(KX) used for determining presence or absence of knocking 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 median value V(50) of magnitude values LOG(V) as the determination value V(KX).

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 executes a program including the steps of: calculating a magnitude value LOG(V) from a magnitude V detected using a knock sensor; calculating a median value V(50) and a standard deviation a of calculated magnitude values LOG(V); calculating a knock determination level V(KD) that is a value obtained by adding the product of standard deviation a and a coefficient U(3) to median value V(50); and when knock determination level V(KD) is greater than the product of determination value V(KX) and a coefficient K, decreasing determination value V(KX). When a knock magnitude N calculated using magnitude V is greater than determination value V(KX), ignition timing is retarded.