A method of deriving reciprocating device component health includes receiving a signal from a knock sensor coupled to a reciprocating device, deriving total harmonic distortion (THD) at one or more frequencies, and determining whether the derived THD exceeds a threshold value.

Disclosed is a method for determining reliability regarding misfire determination of cylinders of an engine, comprising detecting a pressure in an exhaust manifold for a set of operation parameters comprising a certain range of crank angles for a certain engine load and certain engine speed so as to, for an actual cylinder setup of the engine, create pressure sample value patterns for combustion and misfire conditions. A template course is created for the thus created pressure sample value patterns comprising a set of sample points. The pressure for the created template courses is normalized at a desired crank angle. Difference values are determined based upon differences between sample points and corresponding detected and the normalized pressure values. The determined difference values are summarized so as to determine whether a predetermined share of the summarized difference values lies above or below a predetermined threshold value indicating reliability regarding misfire determination.

Systems and methods for estimating an engine event location are disclosed herein. In one embodiment, a control system is configured to receive feedback from at least one vibration sensor coupled to a reciprocating engine, estimate an engine parameter based at least on the feedback and an Empirical Transform Function (ETF), estimate a location of an engine event based on the engine parameter, and adjust operation of the reciprocating engine based at least on the location of the engine event.

Disclosed is a method for determining reliability regarding misfire determination of cylinders of an engine, comprising detecting a pressure in an exhaust manifold for a set of operation parameters comprising a certain range of crank angles for a certain engine load and certain engine speed so as to, for an actual cylinder setup of the engine, create pressure sample value patterns for combustion and misfire conditions. A template course is created for the thus created pressure sample value patterns comprising a set of sample points. The pressure for the created template courses is normalized at a desired crank angle. Difference values are determined based upon differences between sample points and corresponding detected and the normalized pressure values. The determined difference values are summarized so as to determine whether a predetermined share of the summarized difference values lies above or below a predetermined threshold value indicating reliability regarding misfire determination.

Systems and methods for estimating an engine event location are disclosed herein. In one embodiment, a control system is configured to receive feedback from at least one vibration sensor coupled to a reciprocating engine, estimate an engine parameter based at least on the feedback and an Empirical Transform Function (ETF), estimate a location of an engine event based on the engine parameter, and adjust operation of the reciprocating engine based at least on the location of the engine event.

A method and a device for controlling knocking in an internal combustion engine. A knock signal of a cylinder of the internal combustion engine is measured by a knock sensor and from that, a knock feature is generated. The knock feature is compared to a reference level in order to classify a combustion as a knocking or non-knocking combustion. The reference level is formed in consideration of a plurality of corrected knock features, the corrected knock features being formed from the knock features by determining map values from a program map as a function of operating parameters of the internal combustion engine and linking them additively, or by carrying out a low-pass filtering, or by determining map values from a program map as a function of operating parameters of the internal combustion engine and linking them additively and carrying out a low-pass filtering.

The disclosure provides a spectrum calculation device and a spectrum calculation method, in which an inner product of a predetermined number of sampling data x.sub.n obtained by sampling and predetermined kernel functions is calculated, and spectra Spec(f.sub.i) for predetermined frequencies f.sub.i are calculated by calculating a square root of a sum of squares based on the calculated inner products. A difference between a latest data (x.sub.k, t+1)) among the predetermined number of sampling data upon calculation of the inner product and an oldest data (x.sub.(1, t)) among the predetermined number of sampling data in a previous calculation is respectively multiplied by first and second kernel functions, and an obtained value is added to a sine inner product value InSin(f.sub.i, t) and a cosine inner product value InCos(f.sub.i, t) obtained in the previous calculation, to update a sine inner product value InSin(f.sub.i, t+1) and a cosine inner product value InCos(f.sub.i, t+1).

Systems and methods for estimating an engine event location are disclosed herein. In one embodiment, a control system is configured to receive feedback from at least one knock sensor coupled to a reciprocating engine, estimate an engine parameter based at least on the feedback and an Empirical Transform Function (ETF), estimate a location of an engine event based on the engine parameter, and adjust operation of the reciprocating engine based at least on the location of the engine event.

A method for managing knock in a cylinder of an internal combustion engine, in a system including at least one acoustic sensor and a processor, in order to take into account acoustic pollution resulting from a noise, the method including: forming and digitizing the signals of the acoustic sensor, applying a bandpass filter to obtain a filtered noise, determining an adjustable gain-correction function using a gain-correction curve and, depending on the angular position of the end of injection, the point on the gain-correction curve to be used to convert the filtered noise into a corrected knock score, comparing a corrected knock score thus obtained to a knock decision threshold, to correct the timing advance, the gain-correction curve being defined by a calibration value and four angular points obtained by calculation based on the start and end positions of a knock-observation window and on a known characteristic of the noise.

A method and system for predicting the occurrence of a knock which will have a predetermined intensity or higher (intense knock) in an engine that burns an air-fuel mixture of gasoline fuel. The pressure in a combustion chamber is detected during an initial stage of combustion. This pressure is compared with a preset reference value to determine whether or not the cylinder inner pressure exceeds the reference value during the combustion. When the cylinder inner pressure exceeds the reference value, it is predicted that the intense knock will occur before an end of the combustion. If the intense knock is predicted, additional fuel or other material can be injected into the combustion chamber to prevent the occurrence of the intense knock.