An ECU controls a passage switch valve according to the operation state of an engine, to control the temperature of intake air introduced into the engine, by selectively causing outside air from an outside air inlet, high-temperature air from a high-temperature passage, or mixed air comprising the outside air and the high-temperature air to flow towards the downstream side of an intake passage. The ECU calculates the MBT ignition timing and the knock limit ignition timing based on detection results of sensors, and controls the passage switch valve such that, when the knock limit ignition timing is at a more advanced angle than the MBT ignition timing, the high-temperature air or the mixed air is introduced into the engine, and when the knock limit ignition timing is the same as or at a more delayed angle than the MBT ignition timing, the outside air is introduced into the engine.

Provided are a knocking determination device and a knocking control device for an internal combustion engine, with which a large amount of knocking can be detected quickly and with which knocking is easily determined. A knocking time window and a bandpass filter (BPF) are used (B1-B2) to extract a knocking frequency waveform signal from a knock sensor signal (Sg1), and integration is performed to obtain a first calculated value (B3). A reference time window and a BPF are used (B4-B5) to extract a reference frequency waveform signal from the knock sensor signal (Sg1), and integration is performed to obtain a second calculated value (B6). The average value of multiple instances of the second calculated value is obtained (B7), and the first calculated value is divided by the average value to obtain a signal-to-noise (S/N) ratio (B8). A multiplied value is obtained (B9) by multiplying the S/N ratio by a weighting coefficient, a moving average value for several of the multiplied values is obtained (10), and the moving average is used as a knocking indicator to determine knocking and to perform a control (B11-13).

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.

Systems and methods for estimating when an engine event occurs is described. The system includes a controller configured to receive a first signal from at least one knock sensor coupled to a combustion engine, receive a second signal from at least one engine crankshaft sensor coupled to the combustion engine, transform the first and second signals into a plurality of feature vectors using a multivariate transformation algorithm, determine an expected window of an engine event with a statistical model, center a segment of the plurality of feature vectors around the expected window, estimate, using the statistical algorithm, a time in the expected window corresponding to when the engine event occurred, and adjust operation of the combustion engine based on the time.

A method of operating an internal combustion engine with at least one piston-cylinder unit, and preferably a plurality of the piston-cylinder units, whereby, in a detection mode of the internal combustion engine one or more knock-promoting measures are taken until knocking has occurred in at least one piston-cylinder unit, and the measure(s) is/are intensified until a termination criterion is reached, whereby it is detected in which of the piston-cylinder units knocking has occurred, and whereby, in piston-cylinder units detected as knocking, the ignition time for a normal operating mode of the internal combustion engine is retarded.

An ion processing system for collecting and processing combustion information to improve engine efficiency and decrease engine emissions. The ion processing system generally includes a processing unit which is adapted to receive signals from engine sensors such as the crank sensor, injector sensor, and cam sensor. An ion sensor is provided to detect all phases of combustion and generate an ion current signal to be received by the processing unit. Signal conditioners are provided for each individual signal source (crank sensor, injector sensor, cam sensor, ion sensor) to amplify and filter the signals for optimal detection and analysis by the processing unit. The processing unit may monitor crank positioning, cam positioning, and injector timing across all stages of operation of an engine in real-time. This information may be processed and communicated to an engine control unit to improve efficiency and reduce emissions, or to a computing device for diagnostics.

A method or system to determine peak firing pressure of a cylinder of an engine having a crank shaft. The method includes accessing a knock signal received from a knock sensor of the cylinder. The method includes determining a location of peak firing pressure based at least in part on the knock signal. The location of peak firing pressure is associated with combustion of the engine and corresponds to a time or a crank angle of the crankshaft. The method includes generating an indication of the location of peak firing pressure.

A method and system for monitoring at least one reciprocating machine having a crankshaft and at least one cylinder, comprising providing at least one sensor for monitoring the at least one cylinder, the sensor being in communication with at least one processor configured to measure at least one signal from the at least one sensor and to thereby determine an angular position of the crankshaft; selecting at least one subset of potential crankshaft angular positions; calculating at least one statistic associated with the at least one subset of possible crankshaft angular positions based at least partially on data from the at least one sensor; and automatically providing a user with at least one warning or automatically shutting down the machine if the at least one statistic exceeds at least one predetermined threshold; wherein, the at least one sensor comprises at least one acoustic emission sensor.

A computer-implemented platform may comprise hardware and software configured to manage an engine using knock intensity data. Knock intensities from a plurality of combustion cycles may be used to estimate a statistical distribution of knock intensities. The distribution of knock intensities may be used to determine a Descriptive Statistic, which may represent a state of tune of the engine. A calculated Descriptive Statistic may be compared to a desired Descriptive Statistic (e.g., that is representative of operation during a desired tune state of the engine). A deviation between the calculated and desired knock intensity distributions (e.g., between the calculated DS and desired DS) may be used to adjust a control parameter of the engine. Adjustment may be engine-wide. Adjustment may be cylinder-by-cylinder.

A method of deriving the health of a first cylinder in a reciprocating device includes receiving a first signal from a first knock sensor in proximity to the first cylinder, receiving a second signal from a second knock sensor in proximity to a second cylinder, processing the first signal and the second signal, and deriving the health of the first cylinder by determining whether the first signal is coherent with the second signal.