A method of monitoring an operating event of a combustion engine includes receiving a noise signal sensed by a knock sensor disposed in or proximate to the combustion engine, correlating the noise signal with a musical instrument digital interface (MIDI) fingerprint having at least an ADSR envelope indicative of the operating event, and detecting if the operating event has occurred based on the correlating of the noise signal with the fingerprint.

A reciprocating internal combustion engine includes an in-cylinder pressure sensor and a crank angle sensor. Data of calculated heat release amount in synchronization with crank angle is calculated using in-cylinder pressure after absolute pressure correction. An amount of heat release amount variation is calculated as a difference between a first calculated heat release amount at a first crank angle on an advanced side of TDC and a second calculated heat release amount at a second crank angle symmetrical about TDC. An actual heat release amount is estimated based on the amount of heat release amount variation calculated using, as the first crank angle, a crank angle on an advanced side of a combustion start point and using, as the second crank angle, a crank angle on a retarded side of a combustion end point.

An internal combustion engine includes: a cylinder block in which a cylinder is formed; a cylinder head including an intake port and an exhaust port, the cylinder head being integrally formed with the cylinder block; a water jacket covering circumferences of the cylinder, the intake port, and the exhaust port; a partition wall dividing the water jacket into a cylinder block side and a cylinder head side; and a knock sensor mounting boss provided on a side surface of the internal combustion engine, at a position on an extension line of the partition wall.

A method of detecting uncontrolled combustion in an internal combustion engine includes sampling in-cylinder pressure sensor configured to measure pressure in a cylinder of the engine and generate a pressure signal, calculating a combustion intensity metric based on the pressure signal, determining a parameter describing how close the engine is to an uncontrolled combustion condition based on the combustion intensity metric, and controlling a substitution rate of a first fuel and a second fuel based on one or more of the parameter and the combustion intensity metric.

A sensor failure diagnostic apparatus includes a first estimation unit to estimate a mixing ratio of each type of a molecular structure included in a fuel, based on combustion parameters when a combustion of an internal combustion engine is executed in different combustion conditions, among the combustion parameters sensed by a combustion sensor, a second estimation unit to estimate the mixing ratio, based on characteristic parameters sensed by a characteristic sensor, a combustion sensor diagnostic unit to determine whether a failure of the combustion sensor exists, based on a sensed value of the combustion sensor when the combustion is not executed, and a characteristic sensor diagnostic unit to determine whether a failure of the characteristic sensor exists, by comparing the mixing ratio estimated by the first estimation unit with the mixing ratio estimated by the second estimation unit when the combustion sensor diagnostic unit determines the combustion sensor is normal.

The present disclosure includes systems and methods for monitoring a prechamber of an engine. In one embodiment, a system includes a combustion engine having a combustion chamber and a prechamber, where the prechamber is configured to direct a flame toward the combustion chamber, a fuel supply valve configured to adjust a flow of a fuel toward the prechamber, a prechamber valve configured to receive the fuel into the prechamber, a knock sensor coupled to the combustion engine, and a controller. The controller is configured to control operations of the combustion engine, to receive a signal from the knock sensor, to determine a combustion parameter based at least on the signal, to determine a condition of one or both of the prechamber and the prechamber valve based at least on the combustion parameter, and to adjust the fuel supply valve based at least on the condition.

A heat shield film is formed on a bottom surface of a cylinder head and a heat shield film is formed on an inner peripheral surface of a small diameter hole portion. The film is a thermal spraying film made from the same film material. Since the film is thicker than the film, the film has higher thermal capacity than the film and thus heat retaining effect of the film is higher than that of the film. Therefore, combustion gas generated in a combustion chamber is suppressed to lose its momentum around the portion. Even if the combustion gas goes off around the portion, excessive temperature decrease of the combustion gas in the portion is suppressed.

Methods and systems are provided for coordinating cylinder deactivation adjustments with changes to individual cylinder piston displacement. In doing do, the benefits of variable displacement and variable compression ratio may be synergized. An engine can be operated with some cylinders deactivated while active cylinders operate with knock addressed while spark timing is at MBT for a longer duration.

An imbedded control system is disclosed for use with an engine having a combustion chamber and an associated piston. The control system may have at least one sensor configured to generate a signal indicative of a combustion process occurring inside the combustion chamber, and a controller in communication with the at least one sensor. The controller may be configured to determine an amount of heat and a pressure generated inside the combustion chamber based on the signal and a combustion model, to determine a heat flux through the piston based on the amount of heat and a heat flux model, and to determine a temperature at a rim of the piston based on the heat flux and a thermal model. The controller may be further configured to track a time at the temperature and the pressure, and to determine a damage count of the piston based on the time.

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.