Abstract: A knock detection module for an engine comprises a statistics storage module and a processing module. The statistics storage module stores M times N vibration profiles corresponding to M zones of operation of the engine and N cylinders of the engine, wherein M and N are integers greater than one. The processing module determines in which one of the M zones the engine is operating and determines whether knock has occurred for one of the N cylinders by comparing measured vibration data with a selected one of the vibration profiles corresponding to the one of the M zones and the one of the N cylinders.

Abstract: An aircraft engine includes a cylinder assembly knock detection and suppression system. The knock detection and control system includes a set of knock detection sensors and an engine controller. Each cylinder assembly of the aircraft engine carries a knock detection sensor and each knock detection sensor is electrically coupled to the engine controller. During operation, each knock detection sensor transmits signals to the engine controller where the signals correspond to detected cylinder assembly vibrations. As the engine controller receives input signals from the sensors, the engine controller filters the input signals to distinguish the input signals as being associated with either knocking or as a non-knock event. In the case where the engine controller detects the occurrence of one or more knock events in a particular cylinder assembly, the engine controller automatically reduces the spark timing for that cylinder assembly and/or increases the volume of fuel delivered to that cylinder assembly.

Abstract: A method for calibrating an engine is provided. The engine includes a cylinder for combustion of a fuel. The method includes setting combustion parameters of the engine, detecting a combustion noise during combustion proximate to the cylinder, detecting an engine sound radiated from the engine during combustion, adjusting the combustion parameters and repeating the steps of detecting a combustion noise and detecting an engine sound. The method further includes generating a relationship between the combustion noises and the engine sounds, determining a combustion noise level that correlates to a predefined engine sound threshold from the relationship, adjusting a speed of the engine and a load on the engine and repeating the previous steps to determine a combustion noise level for each engine speed and engine load setting, and calibrating the engine using the combustion noise levels.

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: 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: 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 band pass filter processing extracts the vibration component (frequency component) of the 1st to the 4th order frequency band from the output of the knock sensor. A primary frequency band is established as the frequency band containing the fundamental frequency (primary resonance frequency) which is the lowest frequency of the knocking vibration frequencies. The 2nd to the 4th order frequency band is established as the frequency band containing the 2nd to the 4th order resonance frequency. Based on the vibration strength of the primary frequency component, the comparison result between the composite vibration waveform which compounded the 1st to the 4th order frequency component and the ideal knock waveform, and the vibration strength of the summation of the 1st to the 4th order frequency component, the noise and knocking are distinguished from each other with sufficient accuracy.

Abstract: In determining a knock of an engine, a vibration intensity is calculated by logarithm-transforming a peak value or an integral value of an output signal of a knock sensor. Further, a central value VMED of a vibration intensity distribution is calculated, and also a standard deviation ? in a region where the vibration intensity is smaller than this central value VMED is calculated. A vibration intensity reference value VIB is calculated as VMED?u×?, thereby setting the vibration intensity reference value VIB to be close to a minimum of the vibration intensity distribution. Further, a knock reference value KCK is set by adding a predetermined value K to the vibration intensity reference value VIB. The vibration intensity detected by the knock sensor is compared with the knock reference value KCK to determine presence/absence of a knocking.

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 ignition timing control apparatus can obtain high output torque without generating output torque loss, and avoid the deterioration of audibility due to successive knock occurrences. A cylinder specific ignition timing setting section includes a reference ignition timing control section, and a cylinder specific correction value setting section having correction values of the same number as that of engine cylinders. The reference ignition timing control section calculates reference ignition timing common to all the cylinders and uniformly controls the ignition timings of all the cylinders to a retard angle side to prevent the occurrence of successive knocks.

Abstract: In an internal combustion engine, a structure-borne noise generated in a combustion chamber is detected by a structure-borne noise sensor. A quantity is ascertained on the basis of the structure-borne noise signal. A reference quantity of an undrifted structure-borne noise sensor is ascertained for a certain reference operating state for the combustion chamber, during continuous operation of the engine the quantity is ascertained for the reference operating state, and from a change over time of the ascertained quantity with respect to the reference quantity, a drift of the structure-borne noise sensor is ascertained.

Abstract: A system and method for detecting and mitigating preignition for a multi-cylinder engine is provided. According to one aspect of the disclosure, a method is provided including identifying a preignition event at an affected cylinder; deactivating the affected cylinder during a deactivation period; initiating an accommodation system for one or more unaffected cylinders; and activating an indicator system.

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 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: 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: 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: A waveform knock signal detected by a knock sensor is filtered through a band-pass filter. The detected wave form signal is compared with an ideal reference knock waveform to determine an engine knock. The ideal reference knock waveform is derived on the basis of a factor depending on a crank angle, a factor depending on a real time and a factor depending on an engine construction. The factor depending on the real time is calculated based on an energy loss in a combustion chamber and a time constant of the band-pass filter. The factor depending on the engine construction is calculated based on a knock vibration which is generated in a cylinder, transferred to a cylinder block and detected by the knock sensor.

Abstract: A knock determining apparatus includes a sensor which outputs a waveform signal corresponding to a knock state, and at least one of a first to a third knock determiner which determines a knock state based on a vibration intensity distribution of the waveform signal. A knock detector compares the vibration intensity of the waveform signal with a threshold, and detects a knock when the vibration intensity exceeds the threshold. This threshold is corrected based on a knock determining result by the first to the third knock determiner.

Abstract: One end of a rod-like pressure-conveying member is disposed in a sensing unit, and the other end extends into and through an insertion hole of an engine. A combustion pressure, to which the other end of the rod-like member is exposed, is conveyed to the sensing unit through the pressure-conveying member for the detection of the combustion pressure. The pressure-conveying member resonates at a knocking frequency fn of the engine and the knocking frequency fn is detected based on the resonance of the pressure-conveying member.

Abstract: A knock sensor for an internal combustion engine with an electronically evaluated vibration sensor should have a simple design and allow a rational installation. To this end, the vibration sensor is characterized in that the knock sensor comprises at least one spring washer (4, 4?) that is or can be tensioned relative to the internal combustion engine, and a piezoresistive amorphous carbon layer (5) is applied onto at least one face of the at least one spring washer (4; 4?).

Abstract: A method and system to reduce vibration in a turbine-generator including measuring a magnitude of radial vibration of a turbine shaft with at least one vibration sensor configured to generate a vibration signal indicative of vibration frequency; measuring a generator power output with a power output sensor configured to generate a generator power output signal; detecting vibration frequencies in a rough load zone range; engaging an air injection means when a magnitude of radial vibration detected in the rough load zone range is above a predetermined threshold; storing a generator power output level as a reference level when engaging the air injection means; and disengaging the air injection means when either the measured generator power output exceeds a predetermined level or the measured generator power output differs from the reference level by a predetermined amount.

Abstract: When a knocking detector mounted on a cylinder block of an engine is inspected, the cylinder block is vibrated by a vibrating unit via a housing connected to the cylinder block, and the performance of the knocking detector is judged based on whether or not a peak value of a voltage variation value serving as a detection value of the knocking detector is below a threshold value which has been set based on a peak value of a test voltage variation value serving as a reference value.

Abstract: The pressure in a cylinder of a combustion engine is determined on the basis of vibrations in the engine which are generated during movement of the piston. A vibration signal (S) from a vibration sensor situated on a cylinder is filtered in the region about the piston top dead center position, at the transition from compression to expansion, in a special filter in which a half Hanning filter acts upon the vibration signal before and an exponential filter acts upon the vibration signal after the piston top dead center position. The filtered signal (U) is thereafter converted to a pressure signal (P) on the basis of an established relationship between vibration and pressure. The half Hanning filter has a significantly shorter time window (TH) than the exponential filter (TE). The filter cleans the vibration signal in an advantageous manner and makes more reliable pressure determination possible.

Abstract: The present invention includes an engine diagnostic method and routine, wherein a method of using an ionization signal to perform an engine diagnostic routine includes the steps of detecting the ionization signal; integrating the ionization signal over a first sampling window to generate a first integration ionization value; detecting a peak of the ionization signal over said first sampling window to generate a first peak ionization value; integrating the ionization over a second sampling window to generate a second integration ionization value; detecting a peak of the ionization signal over a second sampling window to generate a second peak ionization value; and diagnosing the engine using said ionization signal.

Abstract: A method of operating a knock detection system of a multi-cylinder piston engine in which the knock detection system comprises a sensor arranged in connection with each cylinder and a measurement circuit connected to the sensor includes running the engine at a load being less than full load and setting the output signal of each separate sensor between certain preset limits by adjusting one or more adjustment variables of the measurement circuit. The values of the adjustment variables for each separate cylinder are stored in the detection system. During normal use, the engine is run and the previously stored values of the adjustment values for each cylinder are used in the knock detection system.

Abstract: In a method and system, the condition of a valve drive, particularly of valve clearance, and the position of at least one valve opening cam of a cam shaft of an internal combustion engine are recorded from processing signals which are generated by at least one impact sound sensor such as an electronic spark sensor. Preferably, at least one characteristic signal sequence is identified from signals generated by the impact sound sensor. The sequence occurs at a particular time during a cycle of the internal combustion engine, and is compared to a stored reference signal. As a result, the condition of a valve drive, e.g. the valve clearance, and/or the position of at least one valve opening cam of the cam shaft can be deduced.

Abstract: A threadless knock sensor (10, 50) includes a sleeve (12, 52) around which a transducer (24, 64) and a load washer (30, 70) are disposed. A frusto-conical disk spring (34, 78) is installed in compression around the sleeve (12, 52) above the transducer (24, 64). The sleeve (12, 52) includes threadless structure for holding the disk spring (34, 78) in compression.

Abstract: When a knocking detector mounted on a cylinder block of an engine is inspected, the cylinder block is vibrated by a vibrating unit via a housing connected to the cylinder block, and the performance of the knocking detector is judged based on whether or not a peak value of a voltage variation value serving as a detection value of the knocking detector is below a threshold value which has been set based on a peak value of a test voltage variation value serving as a reference value.

Abstract: The pressure in a cylinder of a combustion engine is determined on the basis of vibrations in the engine which are generated during movement of the piston. A vibration signal (S) from a vibration sensor (4) situated on a cylinder is filtered in the region about the piston's top dead centre position, at the transition from compression to expansion, in a special filter (6) in which a half Hanning filter acts upon the vibration signal after the piston's top dead centre position. The filtered signal (U) is thereafter converted to a pressure signal (P) on the basis of an established relationship between vibration and pressure. The half Hanning filter has a significantly shorter time window (TH) than the exponential filter. The novel filter (6) cleans the vibration signal in an advantageous manner and makes more reliable pressure determination possible.

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 vibration sensor having a pressure sleeve is described, in which the pressure sleeve (2) may be mounted under pressure on a component causing vibration. To detect a vibration signal, e.g., in the case of a knock sensor, a sensory system (7, 5, 6,) is held by a seismic mass above it on the outside of the pressure sleeve (2) via a screw connection on a contact face of the pressure sleeve (2) under an axial prestress in the direction of the sensory system. The seismic mass (8) has an inside thread and may be screwed onto the sensory system (7) to produce the axial prestress in the direction of the sensory system (7). A seismic mass (8) or the sensory system (7) has at least two opposing grooves (14, 15, 16; 18, 19, 20, 21) running radially opposite one another, so that the plastic may enter an interior space (17) between the sensory system (7, 5, 6,) and the pressure sleeve (2) during extrusion through these grooves.

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 method and an arrangement for evaluating the combustion operations in an internal combustion engine with a model is suggested. The model takes a time-dependent transfer between pressure and structure-borne noise as a basis for the relevant low frequency oscillations and only individual components of the reconstructable pressure signal are used for the determination of combustion-relevant parameters and conditions. Independence of engine speed is achieved with the realization of the time dependency with an angular-dependent transfer function.