Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, all intake valves of an engine cylinder may be deactivated, in response to engine load below a threshold, while operating a first exhaust valve coupled to the first exhaust manifold and a second exhaust valve coupled to the second exhaust manifold at different timings. As a result, intake air may be routed from the intake passage, through an exhaust gas recirculation passage coupled between the intake passage and the first exhaust manifold, and into the engine cylinder via the first exhaust valve.

A method for implementation with the operation of an internal combustion engine, having an ignition plug, which is arranged on a combustion chamber of a cylinder of the internal combustion engine, wherein: in a first step, a cylinder pressure at the ignition time at the combustion chamber is detected, as well as a breakdown voltage at the ignition plug; and in a second step, a current electrode distance of the ignition electrodes, representing a current ignition electrode wear state, is determined based on the detected cylinder pressure, the detected breakdown voltage and a constant of proportionality.

A variable valve, method, and diagnostic system are provided that determine accuracy of a position of a variable valve. The variable valve, method, and diagnostic system are configured to determine a system error, the system error being the difference between a commanded position of the valve and a measured position of the valve provided through a feedback signal of the valve. The variable valve, method, and diagnostic system are further configured to determine that a diagnostic accuracy passing condition is met if: a) the system error is less than a predetermined positive error threshold and greater than a predetermined negative error threshold; b) a rate of change of the measured position exceeds a predetermined positive feedback rate threshold; or c) the rate of change of the measured position is less than a predetermined negative feedback rate threshold.

A method for testing a high-pressure pump, particularly a high-pressure pump which is provided to inject fuel into a combustion engine, the method including filling the high-pressure pump with a fluid prior to switching it on.

Methods are provided for identifying degradation in components of a compressor recirculation valve (CRV). One method includes differentiating between degradation of a throttle of the CRV and a position sensor of the CRV based on each of a throttle inlet pressure and commanded position of the throttle of the CRV. The method also includes utilizing output from the position sensor of the CRV in response to the commanded position of the throttle of the CRV.

A method for detecting a closing time of an injector valve includes receiving a valve current profile of the injector valve, processing the valve current profile using at least a slope discriminator, determining a stuck status and a closing time (if applicable) of the injector valve based on an output of the slope discriminator. An engine control unit configured to detect a closing time of an injector valve is also provided. The engine control unit has a first control logic configured to receive a valve current profile of the injector valve, a second control logic configured to process the current profile using at least a slope discriminator, and a third control logic configured to determine a stuck status and a closing time of the injector valve based on an output of the slope discriminator. Further, a vehicle system including a controller configured to detecting a valve closing time is provided.

A control device for an internal combustion engine including a variable compression ratio mechanism for changing a compression ratio by using an electric actuator prohibits control of changing the compression ratio to a higher compression ratio when a failure occurs in the variable compression ratio mechanism. Thereby, upon failure occurrence, the compression ratio of the variable compression ratio mechanism at the time of the failure occurrence is maintained or reduced to less than this compression ratio so as to protect the electric actuator and prevent abrupt changes in torque.

Methods and systems are provided for diagnosing a positive crankcase valve during a vehicle key-off event. In one example, a method may include controlling a fluid flow from a crankcase of an engine to an intake manifold of the engine via a positive crankcase ventilation valve, and indicating whether the positive crankcase valve is stuck open responsive to spinning the engine unfueled in a reverse direction, and indicating whether the positive crankcase valve is stuck closed responsive to spinning the engine fueled but without spark in a forward direction. In this way, functionality of a positive crankcase ventilation valve may be diagnosed effectively during key-off conditions, which may prevent or reduce engine complications arising from a stuck open or stuck closed positive crankcase valve.

The disclosure relates to a control method for controlling at least one injector valve in a fuel injection system of an internal combustion engine. An opening time of the injector valve is selected such that, in a fault situation in the fuel injection system, an opening time of the injector valve is situated in a pressure valley of a pressure oscillation prevailing in a high-pressure region of the fuel injection system.

A control apparatus for an internal combustion engine includes a turbocharger, a bypass passage, a waste gate valve, a turbo bypass valve, an air-fuel ratio sensor and an electronic control unit. The air-fuel ratio sensor is provided in an exhaust passage downstream of a merging point at which the bypass passage merges with the exhaust passage. The electronic control unit is configured to, when a predetermined acceleration request is established and a required opening degree of the turbo bypass valve is larger than a predetermined reference opening degree, execute air-fuel ratio control for changing an air-fuel ratio of exhaust gas from the internal combustion engine for a predetermined first period, and close the waste gate valve based on a convergence status of detected air-fuel ratio fluctuations. The detected air-fuel ratio fluctuations are fluctuations in air-fuel ratio that is detected by the air-fuel ratio sensor resulting from the air-fuel ratio control.