Abstract: An internal combustion engine includes an internal combustion engine main body including a plurality of cylinders, a knock sensor provided on each of the plurality of cylinders, a control board including an amplification circuit, and a plurality of cables differing in length and each connecting the knock sensor and the control board. The amplification circuit includes, for each of the plurality of cables, a first charge amplifier connected to a first output terminal of the knock sensor via one of the plurality of cables, a second charge amplifier connected to a second output terminal of the knock sensor via one of the plurality of cables, and a differential amplifier configured to take an output of the first charge amplifier and an output of the second charge amplifier as input.

Abstract: Sensor circuits having a filter and methods for filtering a sensor signal are provided. In this case, a passband width of an adjustable low-pass filter or bandpass filter is adjusted on the basis of a comparison of a measure of a signal change of a sensor signal with a threshold value.

Abstract: A vehicle includes an engine including a forced induction device, a knock sensor and a crank angle sensor that detect an occurrence of LSPI, a battery that supplies electric power to a second motor generator, and an ECU. When an occurrence of the LSPI is detected, the ECU restricts a maximum torque, which can be output by the engine with the forced induction device, more than when an occurrence of the LSPI is not detected to prevent an engine operating point from being included in an LSPI area, and when an output of the engine becomes insufficient along with the restriction on the maximum torque, the engine compensates for an amount of the insufficient output with electric power supplied from the battery.

Abstract: An engine including a common rail attached to one side portion of a cylinder block that pivotally supports a crankshaft in a rotatable manner, the one side portion extending along a crankshaft center, and the common rail being configured to supply a fuel to the engine. A flywheel housing that accommodates a flywheel that is rotated integrally with the crankshaft is disposed in one side portion out of opposite side portions of the cylinder block intersecting the one side portion. One end portion of the common rail is disposed above the flywheel housing.

Abstract: Provided is a knock detecting device capable of ensuring knock detection accuracy irrespective of fuel injection conditions even when a period during which injection-valve noise occurs overlaps with a knock determination period. An ECU 9 subjects signals output from a knock sensor, which detects vibrations of an internal combustion engine, to frequency analysis to calculate frequency components (501). The ECU 9 calculates a background level that indicates the average of the frequency components (503). The ECU 9 stores, in association with each other, the number of fuel injections, which indicates the number of fuel injections in a predetermined time period during one combustion cycle, with a learning value, which indicates a frequency-component correction amount (507).

Abstract: Provided is an engine knocking detection apparatus capable of reasonably implementing necessary measures for water and dust proofing and against breaking of a cable, and the like at low cost as well as precisely detecting and effectively suppressing or avoiding knocking while suppressing cost and weight increases as much as possible. The engine knocking detection apparatus is adapted to detect knocking in an engine that adopts a flywheel magneto ignition system with an ignition coil unit securely attached to a cylinder, the ignition coil unit including an iron core, a coil wound around the iron core, and a control circuit board attached to the coil, and has an accelerometer for knocking detection attached to the iron core of the ignition coil unit.

Abstract: Methods and systems are provided for rationalizing an engine knock sensor. In one example, a method may include, responsive to an indication of an engine knock event, correlating an output of the engine knock sensor with an output of an on-board microphone to determine degradation of the engine knock sensor. By rationalizing the engine knock sensor against another on-board sensor (e.g., the on-board microphone), diagnostic fidelity may be increased.

Abstract: A method for detecting a wiring fault in a capacitive sensor (1), such as a knock sensor, connected, via a passive acquisition interface (5), to a communication port (P1), that can be configured in either input mode or output mode, of a computer (2), wherein the communication port (P1) is configured in output mode, and a square wave voltage Vn capable of at least partially charging the capacitors (C6, C7, C8a, C8b, C10) of the acquisition interface (5) and the capacitive sensor (1) is generated during a time interval Tc, after which the communication port is switched to its input mode, so that at least one data element representative of the voltage of the capacitors and of the capacitive sensor is acquired, and finally these data are compared with previously stored reference data so that a wiring fault can be deduced if there is no matching between the data.

Abstract: A single-cylinder internal combustion engine includes a knock sensor mounted thereto to suppress a temperature increase of the knock sensor and at the same time detect knocking with high accuracy. The engine includes a cylinder block having a cylinder provided therein, and a cylinder head connected to the cylinder block. On a surface of the cylinder block and the cylinder head, one or more fins protruding from the surface are provided. On the surface of the cylinder block, a sensor mounting boss protruding from the surface and being continuous with a portion of the one or more fins is provided. A knock sensor arranged to detect knocking is mounted to the sensor mounting boss.

Abstract: In a single-cylinder internal combustion engine fitted with a knock sensor, a temperature increase of the knock sensor is suppressed and prevented, and the reliability of the knock sensor is improved. The engine includes a crankcase, a cylinder block connected to the crankcase, a cylinder head connected to the cylinder block, a sensor mounting boss provided on the cylinder block, and a knock sensor mounted to the boss. Fins are provided on the cylinder block and the cylinder head. A heat insulation member is provided between the boss and the knock sensor.

Abstract: In a single-cylinder internal combustion engine fitted with a knock sensor, a temperature increase of the knock sensor is suppressed and prevented and the reliability of the knock sensor is improved. The engine includes a crankcase accommodating a crankshaft, a cylinder block connected to the crankcase and including a cylinder provided therein, a cylinder head connected to the cylinder block, a sensor mounting boss provided on the cylinder block, a knock sensor arranged to detect knocking and mounted to the boss, a fan to guide air to at least the sensor mounting boss, and an air shroud.

Abstract: Embodiments may provide an engine knock monitoring system that may include an engine block including an engine block body and a cylinder wall defining at least a portion of a combustion chamber. A space may be defined between a top of the cylinder wall and a top of the engine block body. An engine knock sensor may be mounted to the engine block. A pressure pulse transmissive element may be disposed in the space and may be disposed in contact with an outside surface of the cylinder wall and an opposite inside surface of the engine block body.

Abstract: In a knocking sensor, including: a metal shell having a cylindrical portion, and a flange portion that is located on the cylindrical portion, and projected toward an outside of the cylindrical portion in a circumferential direction, an annular weight that is fitted onto an outer circumference of the cylindrical portion, and has an upper surface, an annular piezoelectric element that is fitted onto an outer circumference of the cylindrical portion, and interposed between the flange portion and the weight, and an insulating body that is interposed between the flange portion and the piezoelectric element, a protruding portion that is protruded while being plastically deformed from an inner surface of the cylindrical portion outward in a circumferential direction, and locks the weight in contact with the upper surface of the weight directly or through a member is disposed on an outer circumferential surface of the cylindrical portion.

Abstract: A method of carrying out a vibratory fatigue test of a mechanical part having a fatigue endurance limit, the part including a repair extending partly on a first zone of the part, the method including a preliminary test phase including: selecting a loading mode of the part; determining a cutting of the part defining a truncated part, the cutting of the part being defined to obtain a loading level in the repaired zone equal to the maximum value of an abatement to be validated; selecting a measuring device for the fine control of the fatigue test by the measurement of a stress applied to a point of the part; determining a resonance frequency of the truncated part according to the selected loading mode; implementing a loading according to the selected mode at a given level of the truncated part at the resonance frequency up to rupture of the part.

Abstract: Systems and methods for monitoring health of one or more subsystems of a vehicle system are disclosed. At least one sensor can be operatively coupled to a vehicle subsystem having an operational signature and a control system is coupled to the at least one sensor. Using information provided by the at least one sensor, the control system is structured to generate a reference signature of the subsystem during a learning phase and an operational signature of the subsystem subsequent to the learning phase. Systems and methods for identifying the particular subsystem exhibiting degraded performance are also disclosed.

Abstract: A method for control of an internal combustion engine includes generating, with a microelectromechanical system (MEMS) accelerometer, an acceleration signal representing vibrations of the internal combustion engine. An engine crank angle signal is generated based on the acceleration signal. The engine crank angle signal is compared with a target value. The internal combustion engine is adjusted based upon the comparing.

Abstract: A knock control device is provided in which erroneous knock detection can be reduced by suppressing sudden knock signal changes due to noise, without causing any increase in the number of matching steps, deterioration in the S/N in knock detection and decrease in detection performing frequency. In the knock control device, an open gain is applied to the detected signal only during a knock detection window set in advance by a knock window setting means. The window corresponds to a period in which vibration due to knock arises. During other periods, either a closed gain or an interpolated gain value is applied to the detected signal.

Abstract: In a knock control device of an internal combustion engine equipped with a control unit which updates a background level based on an output signal from a knock sensor and detects the generation of a knock by comparing a variation of the background level with a knock determination value, a determination as to whether the knock is generated is performed by ((variation of first filter value of peak hold value)>((1?filter coefficient)/(1+filter coefficient)×(predetermined value larger than maximum value of variation of peak hold value in case where knock is not generated))).

Abstract: A knock control apparatus for an internal combustion engine can remove regularly generated noise vibration in a simple and appropriate manner. The apparatus includes a knock sensor, a crank angle sensor, a vibration waveform detection unit that detects a vibration waveform of a knock natural frequency component, a vibration waveform average value calculation unit that calculates a vibration waveform average value corresponding to a noise vibration waveform by filtering the vibration waveform over a plurality of ignition cycles, a noise vibration waveform removal unit that removes the noise vibration waveform by subtracting the vibration waveform average value from the vibration waveform, a knock determination threshold value calculation unit that calculates a threshold value based on a peak value of the vibration waveform after removal of the noise vibration waveform, and a knock determination unit that determines whether a knock has occurred, by comparing the peak value with the threshold value.

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 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: A method is described for detecting the independent running and/or the start/stop of an internal combustion engine, in which parameters of the internal combustion engine characterizing the combustion process, especially pressure changes or vibrations, are evaluated for this detection.

Abstract: A knock detection system for an engine includes an intensity module, a knock threshold module, and a detection module. The intensity module determines an engine vibration intensity during a first period of engine operation. The knock threshold module determines a knock threshold based on an ethanol concentration in a fuel supplied to the engine. The detection module determines whether engine knock has occurred during the first period by comparing the knock threshold and the engine vibration intensity.

Abstract: An output signal of a knock sensor is converted by an A/D conversion part in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from an output signal of the knock sensor and the time-varying patterns of vibration intensities in multiple frequency ranges are extracted. A knock determination part computes lengths (crank angle, or time period) from a starting point to a latest terminating point of the time-varying patterns of vibration intensity in at least two frequency ranges, which rise at a same time. The knock determination part executes a knock determination based on whether the lengths are greater than a knock determination threshold.

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: A method is provided for improved diagnostics of an internal combustion engine that includes cylinders, a crankshaft, crankshaft rotation angle sensor (CRAS), a vibro-sensor, a logic-mark sensor, each sensor produces respective signals. The method contemplates receiving the signals dividing them into a plurality of idling cycles, determining the crankshaft's position based on stochastic filtration, quasicontinuous representation of the signal, the Kalman filter, a nonlinear stochastic filter, based on CRAS characteristics and quasicontinuous representation, determining the Riesz generator basis function based on technical characteristics of the vibro-sensor, secondary discreeting of the signals with a replacement of argument, discreeting of a reciprocal function, obtaining a discrete wavelet transform, obtaining a continuous wavelet transform, obtaining a discrete wavelet transform of a reciprocal function, and producing output data.

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 object of the present invention is to provide an abnormality detection device that is used with an internal combustion engine having a valve drive mechanism capable of halting the drive of at least one of an intake valve and an exhaust valve, and able to detect the abnormalities of a valve drive halt function. The internal combustion engine includes a knock sensor capable of sensing the seating sound of the intake valve and/or the exhaust valve. An ECU detects whether a control signal given to the valve drive mechanism is a valve drive signal or a valve halt signal. In accordance with the result of detection by the ECU and the presence of the seating sound in an output of the knock sensor, the abnormality detection device judges whether or not the valve drive mechanism is abnormal.

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: Power tools are taught that may include, for example, means for detecting impact sounds generated, e.g. by a hammer strikes an anvil or by oil pulse from an oil unit. The detecting means may include a receiver (30) adapted to selectively convert sound within a narrow frequency range into electric signals. Preferably, the impact sounds fall within the narrow frequency range of the receiver (30). A processor 38 may be utilized to control the motor (22) in order to stop the rotation of the hammer when a pre-determined number of impact sounds has been detected by the detecting means. In addition or in the alternative, various means for setting various operating conditions are taught, including dials 34, sound sensors 30, keypads and remote control devices 250. Further, means for performing maintenance condition status checks are taught.

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: The method comprises operating a calibration engine, and collecting combustion characteristic data and reference accelerometer signals, which are correlated with each other and stored in a calibration table. The calibration table can be used by an engine to determine a real-time normal combustion characteristic when the engine is operating by collecting a real-time accelerometer sensor signal and cross correlating with the correlated data stored in the calibration table. Accordingly, the apparatus comprises a calibration engine comprising a calibration sensor, a reference accelerometer sensor and a data storage device for storing the collected calibration data that is correlated with the collected reference accelerometer signals, and an engine equipped with an accelerometer sensor, a calibration table and an electronic engine controller programmed to receive real-time accelerometer signals and cross correlate them with reference accelerometer signals to determine a real-time normal combustion characteristic.

Abstract: An engine ECU executes a program including the steps of: calculating an absolute value ?S(I) of the deviation of the vibration waveform detected by a knock sensor and a knock waveform model from each other at each crank angle; when ?S(I) greater than threshold value ?S(0) is present and the number of ?S(I) greater than threshold value ?S(0) is equal to or smaller than Q(1), correcting the vibration waveform; calculating a correlation coefficient K which is a value related to the deviation of the corrected vibration waveform and the knock waveform model from each other; and when the number of ?S(I) greater than threshold value ?S(0) is greater than predetermined number Q(1), calculating the correlation coefficient K without correcting the vibration waveform. Based on the correlation coefficient K, whether knocking is present or absent is determined.

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: A vibration sensor for detecting a vibration of a vibrating object includes a plurality of detecting members. Each of the detecting members includes a vibrating portion disposed to be separated from the vibrating object, a transmitting portion for transmitting the vibration from the vibrating object to the vibrating portion, and a detecting portion disposed on a vibrating face of the vibration portion. The detecting portion outputs an electrical signal corresponding to a resonance of the vibrating portion. At least two of the vibrating portions of the detecting members have resonance frequencies, which are different from each other.

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.

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 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 a step of, when it has temporarily been determined that knocking had occurred because of the presence of an integrated value greater than a product of the reference magnitude and coefficient Y among the integrated values of vibration in fourth frequency band D that includes first to third frequency bands A to C, calculating knock magnitude N using the integrated values in the synthesized waveform of first to third frequency bands A to C and correlation coefficient K calculated from a vibration waveform of fourth frequency band D. Based on a comparison between knock magnitude N and determination value V(KX), whether or not knocking has occurred is determined. If there is no integrated value greater than a product of the reference magnitude and coefficient Y, it is determined that knocking has not occurred.

Abstract: The present invention relates to a knocking detecting device for an internal combustion engine, for controlling a timing at which an ignition coil is actuated according to a knocking occurrence intensity, the knocking detecting device including the signal processing module for processing a signal attributable to knocking occurring in the operation of the internal combustion engine to determine a knocking occurrence intensity, in which the signal processing module includes: signal detecting means for detecting a signal attributable to knocking; frequency intensity calculating means for selecting a plurality of frequencies extracted from an output of the signal detecting means to calculate a frequency intensity; and knocking intensity determining means for finally determining that knocking occurs in a case where it is determined that at least two primary determination results of among a plurality of primary knocking determination results based on the outputs of the frequency intensity calculating means.

Abstract: A device having at least one screw plug for screwing into a first tapped hole of a housing or housing part of the device, the at least one screw plug including a device for sealing, such as a sealing ring, for the connection to the housing in a manner forming a seal, e.g., against the escape of oil. Introduced into the screw plug is a second tapped hole by which a sensor is releasably connectable, e.g., is able to be screwed in. The screw plug includes an end stop for conducting acoustical waves and for the simultaneous mechanical limit for screwing in the screw plug.

Abstract: In an automotive system (300), a knock detection scheme is provided for detecting knock events in an internal combustion engine that are sensed by a transducer structure, such as a non-intrusive acoustic accelerometer sensor (310) to generate sensor signal information which is processed by a signal processing structure (312, 316, 318, 326) which extracts digital signal parameters from the sensor signal information to identify a predetermined pitch frequency (330) and any short-term energy increase (328) in the digital signal information which in combination are used to provide a positive indication of engine knock behavior. When a short term Fourier transform (324) is used to extract the digital signal parameters, time frequency resolution may be improved by appropriately windowing the digital signal being transformed.

Abstract: An output signal of a knock sensor is converted by an A/D conversion part in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from an output signal of the knock sensor, and the time-varying patterns of vibration intensities in multiple frequency ranges are extracted. A knock determination part computes the number of time-varying patterns of vibration intensity which rise at same time. The knock determination part executes a knock determination based on whether the number of the time-varying patterns of vibration intensity is greater than a knock determination threshold.

Abstract: An output signal of a knock sensor is converted by an A/D conversion part in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from an output signal of the knock sensor and the time-varying patterns of vibration intensities in multiple frequency ranges are extracted. A knock determination part computes lengths (crank angle, or time period) from a starting point to a latest terminating point of the time-varying patters of vibration intensity in at least two frequency ranges, which rise at a same time. The knock determination part executes a knock determination based on whether the lengths are greater than a knock determination threshold.

Abstract: A knock sensor signal is converted by an A/D conversion part in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from an output signal of the knock sensor and the time-varying patterns of vibration intensity of multiple frequency ranges are extracted. Contours of the time-varying patterns of vibration intensity in multiple frequency ranges are extracted. Vectors indicating directions along which the vibration intensities vary are approximated by the contour of the time-varying pattern of vibration intensity in each frequency range according to the least-squares method. A knock determination is executed based on whether directions of any two or more of multiple vectors are within a predetermined range. Alternatively, a knock determination is executed based on whether a ratio of length of any two or more of the vectors is within a predetermined range.

Abstract: An output of a knock sensor is A/D converted in a specified knock determination range. In a time-frequency analysis part, data of frequency, time, and vibration intensity are extracted at the same time from the knock sensor output signal and the time-varying patterns of vibration intensities in multiple frequency ranges are extracted. An edge direction and an edge intensity are computed by an edge extraction processing. A correlation value expressing a correlation between time-varying patterns of vibration intensities in multiple frequency ranges and a reference model expressing the feature of knock is computed in a mutual correlation/knock determination part. The correlation value is compared with a determination threshold. When the correlation value is larger than the determination threshold, it is determined that knock is caused. When the correlation value is not larger than the determination threshold, it is determined that knock is not caused.

Abstract: A knock sensor diagnostic system may include a knock sensor. A bias circuit applies a bias voltage to the knock sensor. An input circuit receives an input signal based on the bias voltage. A control module indicates a short circuit associated with the knock sensor based on the input signal. A knock sensor diagnostic system may also or alternatively include a signal generator that generates and applies a test signal with a predetermined frequency to the knock sensor. Another input circuit receives another input signal that is based on the test signal. A control module indicates an open circuit associated with the knock sensor based on the other input signal.

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: In an engine knocking detection apparatus that receives a knocking sensor signal expressing vibration in an internal combustion engine and performs bandpass filter processing of the sensor signal to extract a signal component indicative of engine knocking, during each of respective combustion stroke intervals, the center frequency and/or width of the filter passband is adjusted in accordance with changes that occur, during each combustion stroke interval, in the distribution of sensor signal components that are characteristic of knocking.