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 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 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: comparing a vibration waveform of an engine and a knock waveform model stored in advance to calculate a correlation coefficient K; prohibiting correction when a correction prohibiting condition of a determination value V(KX) is satisfied, the determination value V(KX) compared with a knock magnitude N calculated from the correlation coefficient K so as to control the ignition timing; and correcting the determination value V(KX) based on a magnitude value LOG(V) calculated from a magnitude V of vibration in an ignition cycle in which the correlation coefficient K greater than a threshold value K(1) is calculated when the correction prohibiting condition of determination value V(KX) is not satisfied. The correlation coefficient K is calculated as a smaller value when the vibration waveform includes a waveform of vibration of a noise component as compared with that when the vibration waveform does not include it.

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: A knock waveform model (thick line) is prepared by correcting a line (thin line) representing an average value of a vibration waveform measured in advance to have more moderate inclination. The knocking determination device determines whether knocking occurred in an engine or not, based on a result of comparison between the knock waveform model and a waveform detected by a knock sensor.

Abstract: An engine ECU executes a program including the steps of: setting a knock waveform model corresponding to engine speed sensed by a crank position sensor; calculating knock intensity N based on the result of comparison between a detected waveform and the set knock waveform model; when the knock intensity N is larger than a predetermined reference value, determining that knocking has occurred; and when the knock intensity N is not larger than the predetermined reference value, determining that knocking has not occurred.

Abstract: An engine ECU includes: an A/D (Analog/Digital) converter converting an analog signal transmitted from a knock sensor provided at a cylinder block into a digital signal; a bandpass filter passing only a vibration of a third order tangential resonance mode frequency band; and a bandpass filter passing only a vibration of a fourth order tangential resonance mode frequency band. The engine ECU determines whether the engine knocks, as based on the vibration selected by means of the bandpass filter or bandpass filter.

Abstract: An engine ECU executes a program including a step of calculating a knock intensity N as based on comparing a waveform detected as a waveform of a vibration attributed to knocking with a knock waveform model stored in a memory as a waveform of a vibration attributed to knocking for crank angles except for crank angles where a magnitude of a vibration not attributed to knocking is greater than a predetermined magnitude, a step of determining that the engine knocks if knock intensity N is larger than a predetermined reference value, and a step of determining that the engine does not knock if knock intensity N is not larger than a predetermined reference value.

Abstract: An engine ECU executes a program including a step of calculating coefficient of correlation K that is a value related to a deviation between a vibration waveform and a knock waveform model by comparing the engine's vibration waveform with the knock waveform model stored in advance at a plurality of timings, a step of calculating a knock intensity N as based on a largest coefficient of correlation K among the calculated coefficient of correlation Ks, a step of determining that the engine knocks if knock intensity N is larger than a predetermined reference value (YES at S108), and a step of determining that the engine does not knock if knock intensity N is not larger than a predetermined reference value (NO at S108).

Abstract: For each predetermined crank angular interval, an output of a knock sensor is separated into a plurality of frequency components through a plurality of band-pass filters, and peak values of each frequency component are extracted. Then, a mean and a variance of the peak values are computed for each frequency component. A maximum one of the computed means is selected, and the corresponding frequency component, which is associated with the maximum mean, is selected. It is then determined whether the noise is present based on a ratio between the variance of the selected frequency component and the corresponding mean. If the noise is detected in any of the frequency components, execution of knock determination may be prohibited, or ignition timing feedback control according to a result of the knock determination may be prohibited, or ignition timing may be corrected by retarding the ignition timing.

Abstract: An ECU obtains two data values (a peak value and a waveform correlation coefficient) that show the characteristics of a knock from the output of a knock sensor. The ECO approximately obtains the mean of each data value by smoothing each data value, and approximately obtains a variance by smoothing the squared deviation between the data values before and after the smoothing process. The ECU then computes the square root of the variance to approximately obtain a standard deviation. The ECU normalizes each data value using the mean and the standard deviation, obtains a distribution of the normalized two data values, and calculates a correlation coefficient that shows the correlation between the obtained distribution and an ideal knock distribution. Based on the correlation coefficient, the ECU corrects a knock determination threshold value. Therefore, the mean and the standard deviation of the data values are computed with a small RAM capacity.

Abstract: A plurality of variables representing the characteristics of a knock is obtained from an output signal of a sensor. The variables include a peak value of the knock frequency component in the output signal of the sensor and a waveform correlation coefficient representing the correlation between the waveform of the output signal and an ideal knock waveform, which is the waveform specific to a knock. The peak value and the waveform correlation coefficient are normalized, and a detection distribution is created using the obtained normalized data values. A correlation coefficient for knock determination representing the correlation between the detection distribution and an ideal knock distribution is calculated. The correlation coefficient for knock determination is compared with a predetermined knock determination threshold value, and the knock determination threshold value is corrected in accordance with the comparison result. As a result, the accuracy and the reliability of knock determination are improved.

Abstract: A controller for an engine including a fuel vapor processing mechanism. The controller determines the amount of fuel vapor drawn into an intake passage based on the concentration of fuel vapor purged into the purge passage. The controller corrects the fuel injection amount of a fuel injection valve in accordance with the determined amount of fuel vapor. The controller starts correcting the fuel injection amount from the cylinder that is undergoing an intake stroke when the crankshaft is rotated to a certain crank angle.

Abstract: A controller for an engine including a fuel vapor processing mechanism. The controller determines the amount of fuel vapor drawn into an intake passage based on the concentration of fuel vapor purged into the purge passage. The controller corrects the fuel injection amount of a fuel injection valve in accordance with the determined amount of fuel vapor. The controller starts correcting the fuel injection amount from the cylinder that is undergoing an intake stroke when the crankshaft is rotated to a certain crank angle.

Abstract: An engine ECU executes a program including the steps of: detecting a waveform of vibration of an engine at a predetermined knock detection gate; determining whether a detected vibration's waveform and a knock waveform model stored in memory match within a predetermined range; if the model and the detected vibration's waveform match within the predetermined range, determining that the engine knocks; and if the model and the detected vibration's waveform do not match within the predetermined range, then determining that the engine does not knock.

Abstract: The signal levels of vibration waveform signals outputted by knock sensors are extracted at a filter processing section for each of a plurality of frequency bands. The mean value of the signal levels in the frequency bands at a point in time when variation of the signal levels in the frequency bands is minimum computed, and the mean value is detected as a background level. A knock characteristic parameter, which represents the characteristics of knock, is computed based on the extracted signal levels in the frequency bands. The knock characteristic parameter is compared with the background level to obtain a knock intensity. If the knock intensity is equal to or greater than a knock determination value, it is determined that knock that exceeds a permissible level is occurring. If the knock intensity is less than the knock determination value, it is determined that knock that exceeds the permissible level is not occurring.

Abstract: A plurality of variables representing the characteristics of a knock is obtained from an output signal of a sensor. The variables include a peak value of the knock frequency component in the output signal of the sensor and a waveform correlation coefficient representing the correlation between the waveform of the output signal and an ideal knock waveform, which is the waveform specific to a knock. The peak value and the waveform correlation coefficient are normalized, and a detection distribution is created using the obtained normalized data values. A correlation coefficient for knock determination representing the correlation between the detection distribution and an ideal knock distribution is calculated. The correlation coefficient for knock determination is compared with a predetermined knock determination threshold value, and the knock determination threshold value is corrected in accordance with the comparison result. As a result, the accuracy and the reliability of knock determination are improved.

Abstract: An ECU obtains two data values (a peak value and a waveform correlation coefficient) that show the characteristics of a knock from the output of a knock sensor. The ECO approximately obtains the mean of each data value by smoothing each data value, and approximately obtains a variance by smoothing the squared deviation between the data values before and after the smoothing process. The ECU then computes the square root of the variance to approximately obtain a standard deviation. The ECU normalizes each data value using the mean and the standard deviation, obtains a distribution of the normalized two data values, and calculates a correlation coefficient that shows the correlation between the obtained distribution and an ideal knock distribution. Based on the correlation coefficient, the ECU corrects a knock determination threshold value. Therefore, the mean and the standard deviation of the data values are computed with a small RAM capacity.

Abstract: Based on results of a knock control for adjusting ignition timing in accordance with the occurrence of knocking, an electronic control unit computes deposit required ignition timing akgrg, which is ignition timing determined by taking adhesion of deposits in an internal combustion engine into consideration. Based on the deposit required ignition timing akgrg, the electronic control unit reduces a vvt allowable variable range of a target VVT advancement amount, which is a control target value of a variable valve timing mechanism. The electronic control unit corrects a required ignition timing based on the actual VVT advancement amount vt, which is chanted according to the reduction of the allowable variable range of the target VVT advancement amount. As a result, problems resulting from the adhesion of deposits are effectively avoided.