A system for diagnosing a misfire of an engine includes a sensing unit including at least one sensor for detecting at least one detection value associated with an operation of the engine, and an electronic control unit configured to determine whether a misfire of the engine due to exhaust valve leakage has occurred based on the detection values from the sensing unit, and perform an operation corresponding to the misfire due to exhaust valve leakage when the misfire due to exhaust valve leakage has occurred, wherein the electronic control unit a misfire code for exhaust valve leakage in a memory when the misfire due to exhaust valve leakage has occurred.

An engine unit includes an internal combustion engine and a misfire detection device. The misfire detection device includes a rough road traveling determination unit that: (a) determines a rough road traveling state based on a distribution state of a crankshaft rotation speed fluctuation physical quantity acquired by a crankshaft rotation speed fluctuation physical quantity acquisition unit, or (b) includes a vehicle traveling state detection unit for detecting a physical quantity in relation to a vehicle traveling state except the crankshaft rotation speed fluctuation physical quantity, and determines a rough road traveling state based on a detection result obtained by the vehicle traveling state detection unit; and suspends a determination of a misfire in the internal combustion engine based on a determination result obtained by the rough road traveling determination unit.

Systems and methods are provided for determining and correcting air/fuel imbalance between cylinders of an internal combustion engine. A deactivation strategy is determined and implemented. An evaluation is made of whether the engine is operating with an air/fuel imbalance between cylinders. When an imbalance is identified, an alternate deactivation strategy is implemented. Based on outcomes of the alternate deactivation strategy, a source cylinder of the air/fuel imbalance is identified, and fuel flow to the source cylinder is corrected.

A method for aligning cycles of an engine conditioning monitoring system includes: receiving data corresponding to a TDC angle of an engine from a crank angle sensor; receiving data from one or more accelerometers for each cylinder of the engine, the received data including vibration amplitude data; analyzing vibration amplitude data from the one or more accelerometers in relation to data corresponding to the TDC angle of the engine; characterizing vibration data using segmental band analysis, wherein segmental bands of the segmental band analysis correspond to valve closure angles of the engine; identify cylinders for which analyzed vibration amplitude data in relation to the TDC angle of the engine are out of phase; and align vibration amplitude data by shifting analyzed vibration amplitude data relative to the TDC angle of the engine such that vibration amplitude data is aligned with the TDC angle of the engine.

A vehicle predictive control system based on big data includes: a vehicle terminal, which is installed in each of a plurality of vehicles, collecting status information related with an in-vehicle device in a corresponding vehicle to transmit the collected status information in real time, and transmitting problem occurrence information upon problem occurrence of the in-vehicle device; and a big data service provider classifying and storing the status information received from the vehicle terminal as big data, and obtaining a problem occurrence condition based on the status information to transmit information corresponding to the problem occurrence condition to the vehicle terminal when receiving the problem occurrence information of the in-vehicle device from the vehicle terminal of at least some vehicles among the plurality of vehicles.

Misfire classification method for an internal combustion engine, comprising: a step of determining whether the engine is subjected to a misfire; a step of obtaining at least one temperature signal being indicative of a temperature prevailing in a cylinder of the engine; and a step of determining a type of misfire in dependence on the obtained temperature signal.

Presented are multi-pulse fuel injection systems for monitoring engine fuel injectors for missed pulses, methods for making/using such systems, and vehicles equipped with such systems. A method of operating a fuel injection system includes an engine controller determining if the system's injectors are operating in a multi-pulse mode for injecting multiple fuel pulses per combustion cycle to an engine's cylinders and, if so, monitoring pulse signals transmitted to the injectors for injecting the multiple fuel pulses. For each combustion cycle for each injector, the controller flags a cylinder misfire if any one of the fuel pulses for that combustion cycle is missed. For each cylinder, the controller calculates a misfire ratio of a total number of cylinder misfires to a total number of combustion cycles; if one of these misfire ratios exceeds a calibrated misfire limit, the controller commands a resident subsystem to execute control operations to mitigate the misfires.

A big data-based driving information provision system may include a sensor configured to measure and collect state monitoring data of an engine, vehicle monitoring data, and vibration data; an engine electronic control unit (ECU) configured to generate a combustion characteristic index (CCI) data of the engine; and a graphic controller configured to generate a primary deep learning model which classifies the big data including the state monitoring data, the vehicle monitoring data, the vibration data, and the CCI into at least two categories.

Methods and systems are provided for detection of cylinder misfire in an engine. In one example, a system may comprise a first cylinder and second cylinder of the engine having exhaust flows combined together in an exhaust system before being combined with other cylinders of the engine. The first cylinder and second cylinder may share an exhaust gas sensor mounted in the exhaust in a position to sense exhaust from the first cylinder and second cylinder, and being positioned before exhaust from other cylinders is combined with sensed exhaust from the first cylinder and second cylinder. The system may further include a control system with instructions stored therein to indicate detected misfire in one or more of the first and second sensors based on an output from the exhaust gas sensor.

A reignition processing device for a gas engine for executing a reignition process of a cylinder during operation of a gas engine having multiple cylinders is provided with: an execution permission unit configured to, when at least one of the cylinders misfires, perform permission determination whether to execute the reignition process of the misfiring cylinder, on the basis of a damage diagnosis result based on an in-cylinder pressure of the misfiring cylinder, presence or absence of abnormality in a control device which performs combustion control and combustion diagnosis of the gas engine, an operational history related to the misfiring cylinder, and an operational state of the gas engine; and a reignition execution unit configured to execute the reignition process of the misfiring cylinder that is permitted by the permission determination to execute the reignition process.