A control for an internal combustion engine makes an air-fuel ratio in at least one of a plurality of cylinders equal to a rich air-fuel ratio smaller than a theoretical air-fuel ratio, makes an air-fuel ratio in each of the other remaining ones of the plurality of the cylinders equal to a lean air-fuel ratio larger than the theoretical air-fuel ratio, executes a temperature raising process for raising a temperature of a catalyst that purifies exhaust gas from the plurality of the cylinders, executes a detection process for detecting a degree of dispersion of the air-fuel ratio among the plurality of the cylinders, and executes a determination process for determining, based on the detected degree of dispersion, whether or not a plurality of fuel injection valves corresponding to the plurality of the cylinders respectively are normal, and executes the detection process while avoiding a period of the temperature raising process.

Methods and systems are provided for providing passive boost pressure monitoring for slow response with higher confidence. A response time of a boost pressure feedback control loop following a boost pressure deviation that is triggered by either system disturbances or operator torque demand is monitored. Slow boost behavior is correlated with boost control degradation affecting drivability and emissions.

An engine fuel delivery system, prognosis system, and method of conducting a fuel pump solenoid prognosis are provided. The engine fuel delivery system includes a fuel pump having a pumping chamber, a closeable inlet valve (such as a fuel pump control solenoid), and a fuel rail to communicate pressurized fuel received from the fuel pump to at least one engine cylinder. The engine fuel delivery system, prognosis system, and method are configured to determine a solenoid current feedback of a fuel pump control solenoid and a variation in the feedback. The fuel delivery system, prognosis system, and method are further configured to indicate a potential solenoid electrical connection fault if the solenoid current feedback is less than a predetermined current threshold and less than a predetermined variation threshold, and to indicate a potential solenoid weakened electromagnetic field fault if the solenoid current feedback is greater than the predetermined variation threshold.

Methods and systems are provided for drying a wet-fouled spark plug during engine flooding conditions. In one example, a method may include, reverse rotating the engine unfueled and activating a heating element of an exhaust catalyst to flow heated ambient air through the combustion chamber to dry the wet-fouled spark plug.

A method for fault diagnosis in an electronic control unit (ECU) of an engine fuel injection system. The method includes keeping the ECU and the engine fuel injection system at a set of pre-defined conditions, measuring an electrical current consumption of the ECU, and detecting a status of the ECU based on the measured electrical current consumption. Keeping the ECU and the engine fuel injection system at the set of pre-defined conditions includes switching the ECU on by switching the engine fuel injection system on, and keeping the engine fuel injection system at a not-running state. Detecting the status of the ECU based on the measured electrical current consumption includes detecting a normal status responsive to the measured electrical current consumption being in a normal electrical current range, detecting a first hardware defect in the ECU responsive to the measured electrical current consumption being in a first electrical current range, and detecting a second hardware defect in the ECU responsive to the measured electrical current consumption being in a second electrical current range.

A method for determining failure of an electromechanically actuated gas shut off valve includes sensing and recording a gas fuel rail pressure and a boost pressure from an air intake manifold at a first time after the dual fuel engine has been started. The method includes opening the gas shut off valve at a second time, holding the gas shut off valve in its open state, and then closing the gas shut off valve after a predetermined interval at a third time. The method includes comparing an actual gas rail pressure decay rate to a threshold gas rail pressure decay rate for the predetermined interval, and determining failure of the gas shut off valve when the actual gas rail pressure decay rate is less than the threshold gas rail pressure decay rate. Upon determining failure of the gas shut off valve, the method also includes initiating a mitigating action.

An internal combustion engine includes a cam-actuated rocker arm assembly with a solenoid-actuated latch that provides for cylinder deactivation or variable valve actuation. The solenoid is in a position where its inductance varies significantly in relation to the position of a latch pin as it translates between latching and non-latching configurations. A sensor is positioned to monitor a current or a voltage in a circuit that includes the solenoid. The sensor data is analyzed to provide diagnostic information relating to the operation of the rocker arm assembly.

A starter controller incorporated in a starter control system for controlling actuation of a first starter and a second starter to start an engine. The second starter is an alternating-current (AC) starter. The starter control system actuates the first starter in response to an engine start-up request, deactivates the first starter before completion of engine start-up, and activates the second starter while the second starter is being rotated by rotation of an engine rotary shaft. In the starter controller, a determination unit is configured to, under a condition where the engine rotary shaft is rotating after deactivation of the first starter, determine whether or not recognition of rotation of the second starter is complete. A fail-safe unit is configured to, if the recognition of rotation of the second starter is complete, perform predefined fail-safe processing responding to an abnormality in the second starter.

An internal combustion engine is provided. The internal combustion engine includes a control device, and at least one injector for liquid fuel. The injector(s) can be controlled by the control device via an actuator control signal. The injector(s) include an injector outlet opening for the liquid fuel which can be closed by a needle. A sensor is also provided for measuring a measurement variable of the injector(s). The sensor is or can be in a signal connection with the control device. An algorithm is stored in the control device, which algorithm calculates a state of the injector(s) based on input variables and an injector model, compares the state calculated via the injector model with a target state, and produces a state signal in accordance therewith. The state signal is characteristic of a change in the state of the injector(s) that occurs during intended use of the injector(s) and/or an unforeseen change in the state of the injector(s). The input variables include at least the actuator control signal and the measurement values of the sensor. A method for operating such an internal combustion engine and an injector is also provided.

Systems and methods are provided for controlling exhaust gas recirculation (EGR). In one example, an engine system includes a first EGR valve coupling an exhaust manifold to an engine exhaust system, a second EGR valve coupling the exhaust manifold to an engine intake system, and a control unit. The control unit selectively adjusts a position of the first EGR valve based on a target amount, and adjusts a position of the second EGR valve based on the target amount and a position of the first EGR valve. Responsive to a first degradation condition of the first EGR valve, the control unit adjusts the position of the second EGR valve based on the target amount and based on a pressure of the first exhaust manifold, and responsive to a second degradation condition of the first EGR valve, adjusts the position of the second EGR valve based on the target amount.