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: 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: 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.

Abstract: A knock detection device that can not only detect knock accurately, but can also detect heavy knock quickly. Cylinder pressure is detected by a pressure sensor installed in each cylinder in an internal combustion engine. AS the occurrence or non-occurrence of heavy knock is determined based on the ratio between the maximum value of cylinder pressure fluctuation and the maximum value of cylinder pressure divided by a prescribed value, it becomes possible to detect the occurrence of heavy knock quickly. If it is determined that heavy knock has occurred, a knock suppression measure involving, for example, reducing the spark advance angle, is immediately applied, thus preventing damage to the internal combustion engine.

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.

Abstract: A knock detection device that can not only detect knock accurately, but can also detect heavy knock quickly. Cylinder pressure is detected by a pressure sensor installed in each cylinder in an internal combustion engine. AS the occurrence or non-occurrence of heavy knock is determined based on the ratio between the maximum value of cylinder pressure fluctuation and the maximum value of cylinder pressure divided by a prescribed value, it becomes possible to detect the occurrence of heavy knock quickly. If it is determined that heavy knock has occurred, a knock suppression measure involving, for example, reducing the spark advance angle, is immediately applied, thus preventing damage to the internal combustion engine.

Abstract: A knock control apparatus has a knock sensor and a signal processor. The signal processor integrates a knock sensor signal and differentiates the integrated signal. The signal processor detects a period in which the differentiated signal exceeds a threshold, and detects a peak of the differentiated signal. The signal processor then calculates a ratio between the detected signal generation period and the detected peak to determine a knock when the calculated ratio is within a predetermined range. Alternatively, the signal processor detects a peak generation time and calculates a ratio between the detected signal generation period and the detected peak generation time. In this instance, the signal processor determines the knock when the calculated ratio is within a predetermined range and the detected peak generation time is less than a predetermined time reference.

Abstract: A knock control apparatus has a knock sensor and a signal processor. The signal processor integrates a knock sensor signal and differentiates the integrated signal. The signal processor detects a period in which the differentiated signal exceeds a threshold, and detects a peak of the differentiated signal. The signal processor then calculates a ratio between the detected signal generation period and the detected peak to determine a knock when the calculated ratio is within a predetermined range. Alternatively, the signal processor detects a peak generation time and calculates a ratio between the detected signal generation period and the detected peak generation time. In this instance, the signal processor determines the knock when the calculated ratio is within a predetermined range and the detected peak generation time is less than a predetermined time reference.