Abstract: A knock control system is configured to precisely determine situations in which the knock signal cannot be detected and to suppress the occurrence of reductions in fuel efficiency, exhaust performance, and output performance. The knock control system has a knock sensor that detects an engine knocking condition to produce a knock signal of a prescribed level and a variable valve mechanism that can change the intake valve closing timing. Based on the ratio of the estimated knock signal during knocking to the estimated noise signal during no knocking, the knock control system determines if an accurate knock signal can be detected. The knock control system also determines if the valve seating position corresponding to the intake valve closing timing is within the knock detection interval and, if so, the estimated mechanical noise component of the estimated noise signal is updated.

Abstract: A knock control apparatus normalizes a knock frequency magnitude and a background noise level to substantially the same levels in all the engine operating conditions in consideration of a variation in an ionic current level due to an environment, the number of revolutions per minute of the engine, an engine load, etc.

Abstract: A knock control system is configured to precisely determine situations in which the knock signal cannot be detected and to suppress the occurrence of reductions in fuel efficiency, exhaust performance, and output performance. The knock control system has a knock sensor that detects an engine knocking condition to produce a knock signal of a prescribed level and a variable valve mechanism that can change the intake valve closing timing. Based on the ratio of the estimated knock signal during knocking to the estimated noise signal during no knocking, the knock control system determines if an accurate knock signal can be detected. The knock control system also determines if the valve seating position corresponding to the intake valve closing timing is within the knock detection interval and, if so, the estimated mechanical noise component of the estimated noise signal is updated.

Abstract: The invention relates to a system for detection of combustion anomalies in an internal combustion engine, and includes a crank angle indicator, a vibration sensor, and a signal processor, wherein the signal processor receives signals from the indicator and the sensor, performs a wavelet transform analysis of the signals from the sensor to develop a vibration frequency signature on a time scale, compares the vibration frequency signature to a predetermined value to determine the existence of anomalies in the combustion process, and compares the time scale of the vibration frequency signature to the signal from the indicator to determine which of a plurality of cylinders of the internal combustion engine is exhibiting the combustion anomaly.

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 method of detecting and controlling detonation, including the steps of: generating (10) a vibration signal (D) proportional to the intensity of vibration on the crankcase; wide-band-filtering (11) the vibration signal (D) to generate a first intermediate signal; rectifying (12) the first intermediate signal to generate a second intermediate signal; integrating (13) the second intermediate signal to generate a first numeric value; calculating (14) a logarithm of the first numeric value to obtain a second numeric value (Xi); calculating (16) a difference between the second numeric value (Xi) and the mean value (&mgr;i) to obtain a third numeric value (&dgr;i) with a predetermined threshold value (&dgr;o); determining (18) the presence of detonation in the event the third numeric value (&dgr;i) has a first predetermined relationship with the predetermined threshold value (&dgr;o); forming (19, 21) a detonation index (Ii) indicating the behavior of the engine in terms of detonation; and obtaining (22) a spark l

Abstract: The total ignition angle ZW(z) of each cylinder z is composed of cylinder-selective values basic ignition angle GZ(z) {determined by engine speed n and load L}, knock adjustment angle KNK(z), in addition to a first adaptation value AD1(z) and a second adaptation value AD2 common to all cylinders. AD1(z) is increased when KNK(z) is greater than a threshold DEC and is reduced when KNK(z) is lower than a threshold INC. The second adaptation value AD2 is formed as a function of the average value {overscore (AD1+L )} of the adaptation values of all cylinders.

Abstract: A method for controlling knocking in internal combustion engines. According to this method, a map ignition angle is determined on the basis of detected operating parameters, to which a correction value is additively applied when knock events occur. The correction value is a function of a knock frequency.

Abstract: Only predetermined frequency components included in an ion current flowing between an ignition plug and the ground are extracted from the ion current by means of a low pass filter and a high pass filter as a knock detection signal, that is, a signal used for knock detection. This knock detection signal is then subjected to A/D-conversion in an A/D-converter to generate A/D-converted values which are subsequently supplied to a processing unit employed in a digital signal processor. In the processing unit, the A/D-converted values are subjected to a discrete Fourier transform (DFT) frequency analysis. Knock determination based on data obtained from the DFT frequency analysis results in information indicating the operating state of the internal combustion engine.

Abstract: The present invention relates to a method for determining the running smoothness of an Otto spark ignition engine by measuring the ionic current (I) in at least one combustion chamber of the Otto spark ignition engine. Once the spark plug has fired, a measuring voltage is applied to the spark plug, inducing the ionic current (I). Following each ionic current measurement, initially an active, average ionic-current value (IM) is defined, and a running-smoothness value (L) is subsequently determined from a reference value and the ionic-current average value (IM).