Abstract: An engine controller includes an ignition timing control unit and a rich imbalance determining unit. The rich imbalance determining unit designates one of multiple cylinders as a subject cylinder for determination and executes lean active control that commands a smaller amount of fuel injection for the subject cylinder than for the other cylinders. The rich imbalance determining unit determines whether an air-fuel ratio of the subject cylinder deviates to be richer based on a rotational fluctuation amount of a crankshaft during the execution of the lean active control. The ignition timing control unit executes an advancement limiting process that limits advancement of the ignition timing by the knock control during the execution of the lean active control.

Abstract: An engine controller includes an ignition timing control unit and a rich imbalance determining unit. The rich imbalance determining unit designates one of multiple cylinders as a subject cylinder for determination and executes lean active control that commands a smaller amount of fuel injection for the subject cylinder than for the other cylinders. The rich imbalance determining unit determines whether an air-fuel ratio of the subject cylinder deviates to be richer based on a rotational fluctuation amount of a crankshaft during the execution of the lean active control. The ignition timing control unit executes an advancement limiting process that limits advancement of the ignition timing by the knock control during the execution of the lean active control.

Abstract: A CPU advances ignition timing within a range in which knocking can be suppressed by feedback control based on an output signal of a knocking sensor. The CPU sets the igniting timing based on a feedback adjustment amount and a learning value. The CPU limits timing advancing update of the learning value when an exhaust pressure is higher than or equal to a threshold.

Abstract: A CPU advances ignition timing within a range in which knocking can be suppressed by feedback control based on an output signal of a knocking sensor. The CPU sets the igniting timing based on a feedback adjustment amount and a learning value. The CPU limits timing advancing update of the learning value when an exhaust pressure is higher than or equal to a threshold.

Abstract: A control device for an internal combustion engine includes an electronic control unit configured to determine whether or not cylinder-specific air-fuel ratio processing is being executed in which an air-fuel ratio of at least one of a plurality of cylinders is controlled to be a rich air-fuel ratio and an air-fuel ratio of at least one of the other cylinders is controlled to be a lean air-fuel ratio. The electronic control unit updates a first learning value in which a result of comparison between a knock strength of the internal combustion engine and a first determination value is reflected when the cylinder-specific air-fuel ratio processing is not being executed. The electronic control unit prohibits updating of the first learning value and calculates a target ignition timing of the internal combustion engine based on the first learning value when the cylinder-specific air-fuel ratio processing is being executed.

Abstract: An ignition timing control apparatus for an internal combustion engine includes an electronic control unit configured to i) perform determination as to whether knocking has occurred in the engine; ii) update a first learning value and a second learning value such that the ignition timing is retarded when determining that knocking has occurred; and iii) derive, as a required ignition timing, a timing obtained by retarding a base ignition timing based on the first and second learning values. The electronic control unit is configured to update the second learning value within a range in which an update amount of the second learning value within a prescribed period set in advance does not exceed a prescribed amount, when updating the second learning value.

Abstract: A control device for an internal combustion engine includes an electronic control unit configured to determine whether or not cylinder-specific air-fuel ratio processing is being executed in which an air-fuel ratio of at least one of a plurality of cylinders is controlled to be a rich air-fuel ratio and an air-fuel ratio of at least one of the other cylinders is controlled to be a lean air-fuel ratio. The electronic control unit updates a first learning value in which a result of comparison between a knock strength of the internal combustion engine and a first determination value is reflected when the cylinder-specific air-fuel ratio processing is not being executed. The electronic control unit prohibits updating of the first learning value and calculates a target ignition timing of the internal combustion engine based on the first learning value when the cylinder-specific air-fuel ratio processing is being executed.

Abstract: An engine includes a variable valve mechanism capable of holding a valve timing of an intake valve in an intermediate phase when the engine is started. An ECU calculates a degree of deposit adhesion in a combustion chamber, and calculates a deposit correction amount that is a retard correction amount for an ignition timing set in accordance with the calculated degree of the deposit adhesion. The ECU calculates a first correction amount that is a first adaptive value for the retard correction amount for the ignition timing in a reference phase of the valve timing and a second correction amount that is a second adaptive value for the retard correction amount for the ignition timing in an adaptation phase of the valve timing. The deposit correction amount is set based on the first correction amount and the second correction amount.

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 output signal of a knock sensor is filtered with a plurality of band-pass filters to extract vibration waveform components of a plurality of frequency bands (f1-f4). Weighting coefficients (G1-G4) which multiply the vibration waveform component of each frequency band are established in such a manner as to be a small value as a noise intensity of each frequency band becomes larger. Thereby, the vibration waveform component of a plurality of frequency bands is synthesized by weighting according to an influence of a noise intensity of each frequency band. Even when the noise is superimposed on the vibration waveform component of any of the frequency bands, it becomes possible to reduce the influence of the noise and to synthesize the vibration waveform component of each frequency band, and an accurate knock determination can be performed based on the composite vibration waveform.

Abstract: An engine ECU executes a program including: detecting a magnitude of vibration of an engine; detecting a vibration waveform of the engine based on the magnitude; calculating a correlation coefficient, in the case where the engine speed is smaller than a threshold value, using the sum of values each determined by subtracting a positive reference value from a magnitude of a knock waveform model, as an area of the knock waveform model and, calculating the correlation coefficient, in the case where the engine speed is not smaller than the threshold value, using the area of the whole knock waveform model; and determining whether or not knocking has occurred using the correlation coefficient. The correlation coefficient is calculated by dividing by the area 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 steps of: calculating a knock magnitude N by dividing an integrated value lpkknk obtained by integrating the magnitude of vibration in the knock detection gate by BGL; controlling ignition timing according to a result of comparison between knock magnitude N and a determination value VJ; stopping updating of a standard deviation ? when it is determined that determination value VJ to be compared with knock magnitude N is to be changed; updating a median value VM by increasing an update amount of median value VM; and updating BGL according to median value VM and standard deviation ?.

Abstract: An output signal of a knock sensor is filtered with a plurality of band-pass filters to extract vibration waveform components of a plurality of frequency bands (f1-f4). Weighting coefficients (G1-G4) which multiply the vibration waveform component of each frequency band are established in such a manner as to be a small value as a noise intensity of each frequency band becomes larger. Thereby, the vibration waveform component of a plurality of frequency bands is synthesized by weighting according to an influence of a noise intensity of each frequency band. Even when the noise is superimposed on the vibration waveform component of any of the frequency bands, it becomes possible to reduce the influence of the noise and to synthesize the vibration waveform component of each frequency band, and an accurate knock determination can be performed based on the composite vibration waveform.

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 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: 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: 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: 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: 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.