Various embodiments include a method comprising: determining a torque output of each cylinder resulting from a fuel injection into the cylinder; determining a difference in the respective torque; comparing the difference in the respective torque output with a threshold; if the difference exceeds the threshold, changing the injection mass for at least one cylinder based on the difference; determining a further torque output of the cylinder resulting from the injection of the changed injection mass; determining whether the further torque output corresponds to the changed injection mass; if the further torque output lies outside a predetermined tolerance range for a corresponding injection mass, setting the injection mass to be injected to the original value; and changing the injection time in at least the one of the at least two cylinders.

A control method for internal combustion engine with a fuel injection valve configured to directly inject fuel into a cylinder and an ignition plug configured to directly spark-ignite the fuel injected from the fuel injection valve includes comparing an actual behavior, which is an actual changing behavior of an engine revolution speed at an engine start, to a reference behavior set in advance, and switching from stratified combustion in which a fuel spray injected from the fuel injection valve and staying around the ignition plug is directly spark-ignited to homogeneous combustion in which a homogeneous air-fuel mixture is formed in a combustion chamber and the fuel is burned and increasing a mechanical compression ratio of the internal combustion engine as compared to the case where the actual behavior and the reference behavior match if the actual behavior is different from the reference behavior.

A motor vehicle is disclosed having an internal combustion engine and an integrated starter-generator drivingly connected to a crankshaft of the internal combustion engine by a belt drive. Operation of the internal combustion engine and the integrated starter-generator is controlled by an electronic controller in response to a number of inputs. The electronic controller is arranged to use the internal combustion engine and the integrated starter-generator to actively reduce driveline shuffle in one of a number of shuffle reduction modes that are selected by the electronic controller based on at least the current rotational speed of the internal combustion engine.

Methods and systems are provided for operating a variable displacement engine that includes a misfire detection system. The misfire detection system corrects engine crankshaft acceleration according to cylinder firing patterns so that misfire detection may be improved. The corrected engine crankshaft accelerations may be compared to threshold crankshaft levels to determine the presence or absence of cylinder misfire.

Method and apparatus for detecting drift of pilot, wherein the method includes: measuring two rotation speeds corresponding to each detection point of at least one detection point when an engine equipped with an injector is in an idle state, wherein the detection point is point(s) of an injection curve measured under the condition that a current injection pressure is applied to the injector when there is no drift of pilot in the injector, energizing time indicated by the point(s) being less than a predefined value, one rotation speed is a rotation speed of the engine during a certain working cycle of a cylinder injected by the injector, the injector being energized for an energizing time indicated by that detection point in a pilot period of the cycle, and another rotation speed is a rotation speed of the engine during an another working cycle of the cylinder, the injector not being energized in the pilot period of the cycle; calculating a current engine rotation speed change corresponding to the detection point; acquiring an indication value corresponding to the detection point; and determining whether there is drift of pilot in the injector, based on the indication value.

Methods and systems are provided for detection of cylinder-to-cylinder air fuel ratio imbalance in engine cylinders. In one example, a method may include indicating air fuel ratio imbalance in an engine cylinder based on a comparison of an estimated cylinder acceleration for the cylinder and a calibrated cylinder acceleration for each of the engine cylinders. The indication of imbalance may be further confirmed based on one or more of an exhaust air-fuel ratio, an exhaust manifold pressure, and an individual cylinder torque weighted by respective confidence factors.

Methods and systems are provided for diagnosing valve operation during a cylinder deactivation event in a variable displacement engine. Crankshaft acceleration data is captured during an exhaust stroke of a deactivated cylinder and compared to a calibrated map of crankshaft acceleration data for the given cylinder. Based on the comparison, it may be indicated that the deactivation of the exhaust valve of the given cylinder is degraded, and that the exhaust valve is open when commanded closed.

Using machine learning for misfire detection in a Dynamic firing level modulation controlled internal combustion engine is described. A neural network is used to calculate expected crank acceleration from various inputs, including the dynamically defined cylinder skip fire sequence. The output of the neural network is then compared to a signal indicative of the measured crank acceleration. Based the comparison, a prediction is made if a misfire has occurred or not. In alternative embodiment, the neural network is expanded to include the measured crank acceleration as an additional input. With the latter embodiment, the neural network is arranged to directly predict misfire events.

A method for controlling an internal combustion engine is provided, which includes defining a first area in which the engine operates in a stoichiometric combustion mode and a second area in which the engine operates in a lean combustion mode, on an operation map defined by the engine load and speed, and causing a controller to determine that an operation point on the operation map shifts from the first area to the second area based on signals from an accelerator opening sensor and a crank angle sensor, predict a length of time that the operation point stays in the second area, switch a combustion mode to the lean combustion mode when the predicted time is longer than a given period of time, and maintain the stoichiometric combustion mode when the predicted time is shorter than the given period of time.

A method for starting a gaseous fuel internal combustion engine is disclosed. According to the disclosed method, the engine is rotated using a start device until a first speed threshold is reached. After reaching the first speed threshold, pilot fuel is supplied to a plurality of cylinders of the engine to combust the same. After performing an ignition health check, gaseous fuel is supplied to all or a relatively large number of cylinders to start accelerating the engine up to a second speed threshold.