Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual noise sources to an engine background noise level. The contributions of the individual noise sources may be the basis for establishing the presence or absence of knock in one or more engine cylinders.

A method for sensing damage to a bearing of an engine using a vibration signal may sense the damage to the bearing even without a sensor for directly sensing the damage to the bearing using a frequency signal input to a knocking sensor from the engine for each traveling state (acceleration traveling, cruise traveling, deceleration traveling) of a vehicle.

A multi-cylinder internal combustion engine is configured to perform an all-cylinder operation and a partial-cylinder operation. The ignition timing controller executes a process that sets a knock control amount and a knock learning value, a process that determines whether knocking is occurring, a process that updates a value of the knock control amount in accordance with whether knocking is occurring, a process that updates the knock learning value such that the knock learning value gradually approaches a knock control operated amount, a process that operates ignition timing of each cylinder based on the knock control amount and the knock learning value, and a process that limits update of the knock learning value such that a followability of the knock learning value to the knock control operated amount is lower during the partial-cylinder operation than during the all-cylinder operation.

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 for operating an internal combustion engine. The method includes detecting a structure borne sound signal in a time-dependent manner for the at least one combustion chamber during operation of the internal combustion engine, and determining, in a predetermined measuring window, at least one evaluation parameter from the detected structure borne sound signal. The method also includes obtaining at least one comparative result by comparing the at least one evaluation parameter with at least one predetermined comparison value, and assigning to the structure borne sound signal, on the basis of the at least one comparative result, one of a knocking event in the at least one combustion chamber and an interference signal.

A method for sensing damage to a bearing of an engine using a vibration signal may sense the damage to the bearing even without a sensor for directly sensing the damage to the bearing using a frequency signal input to a knocking sensor from the engine for each traveling state (acceleration traveling, cruise traveling, deceleration traveling) of a vehicle.

A multi-cylinder internal combustion engine is configured to perform an all-cylinder operation and a partial-cylinder operation. The ignition timing controller executes a process that sets a knock control amount and a knock learning value, a process that determines whether knocking is occurring, a process that updates a value of the knock control amount in accordance with whether knocking is occurring, a process that updates the knock learning value such that the knock learning value gradually approaches a knock control operated amount, a process that operates ignition timing of each cylinder based on the knock control amount and the knock learning value, and a process that limits update of the knock learning value such that a followability of the knock learning value to the knock control operated amount is lower during the partial-cylinder operation than during the all-cylinder operation.

An internal combustion engine according to one or more embodiments of the present disclosure may include an engine cylinder having a cylinder head and cylinder sidewalls and a piston that reciprocates within the engine cylinder. The piston, the cylinder head, and the cylinder sidewalls may at least partially define a combustion chamber. The internal combustion engine may also include a fuel injector that is positioned to inject fuel directly into the combustion chamber. The internal combustion engine may further include an engine control module that is in electronic communication with the fuel injector. The engine control module may determine if the internal combustion engine is operating at conditions corresponding to a super knock condition may occur and commands the fuel injector to operate under a split injection mode in which fuel is injected into the combustion chamber in a plurality of injection pulses.

Disclosed herein is a method of predicting engine knocking, which includes calculating initial pressure in cylinder based on operating data and pressure in intake manifold measured using manifold absolute pressure sensor, calculating pressure at spark timing in the cylinder by interpreting compression process as polytropic process based on the calculated initial pressure in the cylinder, calculating heat release rate for individual operating conditions based on the calculated pressure in the cylinder at spark timing, calculating pressure change in the cylinder based on the calculated heat release rate, calculating unburned gas temperature in adiabatic compression process based on the calculated pressure change in the cylinder, and determining whether knock occurs by calculating ignition delay based on the calculated unburned gas temperature and calculating unburned gas mass fraction at crank angle at the end of the ignition delay.

A control system includes a knock sensor and a controller. The knock sensor is configured to generate a notification signal by sensing a plurality of engine cylinder events in an engine. The controller is electrically coupled to the knock sensor and configured to detect a plurality of stochastic pre-ignition events in response to the plurality of engine cylinder events, calculate a real-time rate of the plurality of stochastic pre-ignition events, calculate a ratio of the real-time rate to an allowable rate of the engine, and adjust a current allowable torque of the engine in response to the ratio and a rotational speed of the engine.