Methods and systems are provided for reducing evaporative emissions in a vehicle during engine-off conditions responsive to an indication of undesired fuel outflow from one or more fuel injectors. In one example, at an engine-off event, an electric motor is operated to spin a vehicle engine unfueled to position a cylinder receiving fuel from a fuel injector with undesired fuel outflow with an intake valve open and an exhaust valve closed, and subsequently an onboard vacuum pump is activated to purge the contents of the cylinder to a fuel vapor canister. In this way, upon detection of undesired fuel outflow from one or more fuel injectors, during engine-off conditions mitigating action may be undertaken such that the undesired fuel outflow is purged to the fuel vapor canister, rather than being released as vapors to the environment.

A control apparatus includes an electronic control unit configured to: carry out a first diagnosis and a second diagnosis; control a first injection valve and a second injection valve such that fuel is injected from both the first injection valve and the second injection valve, and such that a fuel injection amount from the second injection valve is not reduced and a fuel injection amount from the first injection valve is reduced, when carrying out the first diagnosis; and control the first injection valve such that fuel is not injected from the first injection valve, and control the second injection valve such that the fuel injection amount from the second injection valve is reduced in a state where fuel is injected from the second injection valve, when carrying out the second diagnosis.

Methods are provided for identifying degradation in components of a compressor recirculation valve (CRV). One method may include inferring degradation of the CRV based on adaptation of a compressor surge line outside an expected range.

Methods and systems are described for diagnosing degradation of a vacuum actuator in an engine system. An example method comprises indicating degradation of the vacuum actuator based on an estimate of flow of air into and out of a vacuum reservoir. The estimate is further based on flow of air generated via each of an aspirator in the intake system, an actuation of the vacuum actuator, and leakage during the actuation of the vacuum actuator.

A variety of methods and arrangements for detecting failure of the commanded air induction in an internal combustion engine are described. In some embodiments, the intake manifold pressure is monitored. An air induction event generates a fluctuation in the intake manifold pressure, which is recorded. The signal is processed through a diagnostic filter to help determine whether the actual induction matched the commanded induction. In other embodiments, measured crankshaft acceleration is compared with estimated crankshaft acceleration. If the two quantities differ by a threshold amount an induction fault is detected. The two detection methods may also be combined. The describe approaches are particularly well suited for use in engines operating in a skip fire mode with cylinder deactivation and/or a dynamic firing level modulation mode.

A control device for an internal combustion engine controls a control object device based on an output value of a relative angle sensor that detects a relative angle of an output shaft of an actuator, and an output value of an absolute angle sensor that detects an absolute angle of a drive shaft coupled to the output shaft of the actuator via a speed reducer. In this event, the control device for the internal combustion engine corrects an output value of the absolute angle sensor based on an absolute angle of the drive shaft that is obtained from an output value of the relative angle sensor using, as a reference point, an output value of the absolute angle sensor at the start-up of the internal combustion engine, and an output value of the absolute angle sensor.

A control method includes an electronic waste gate actuator (EWGA) and a waste gate valve, connected to each other through a rod. The control method includes an operation condition determination step for determining whether an engine is in cold operation or hot operation by measuring engine soak time and initial coolant temperature when the engine starts and by comparing them with a predetermined reference soak time and reference coolant temperature. The control method also includes a cold control step for setting cold operation reference voltage, performing cold operation learning, and applying cold operation learning data to the cold operation reference voltage, when the engine is in cold operation. The control method further includes a hot control step for setting hot operation reference voltage, performing hot operation learning, and applying hot operation learning data to the hot operation reference voltage, when the engine is in hot operation.

Methods and systems are provided for the mitigation of wet-fouling of the spark plugs of an engine. In one example, a method may include, after spark plug fouling has been detected prior to an engine start, drawing fresh air through the EVAP system of an engine, heating it, and flowing the heated gas through one or more cylinders of an engine while the engine is not rotating.

When opening or closing an exhaust cut valve in accordance with an operation range of an engine and performing feedback control for an opening degree of a wastegate valve such that a target supercharging pressure is achieved in each of an open operation range where the exhaust cut valve is opened and a closed operation range where the exhaust cut valve is closed, a failure of the exhaust cut valve can be accurately determined. Whether or not an abnormal state occurs is determined in each range. In the abnormal state, although feedback control for closing the wastegate valve is performed, the actual supercharging pressure is lower than the target supercharging pressure, and a deviation between the actual supercharging pressure and the target supercharging pressure is maintained at not less than a predetermined value. Further, whether the exhaust cut valve is normal or in failure is determined.

Systems and methods are provided for a diagnostic system for a machine with a combustion engine and a variable geometry turbocharger that includes a vane position sensor. The diagnostic system includes a controller configured to calculate a learned span value of the turbocharger based on the output of the vane position sensor during a diagnostic procedure and a reference vane position sensor value. A plurality of learned span values are calculated each during a different one of a plurality of diagnostic procedures performed over a period of time and a first regression analysis to predict an expected learned span value at a defined future time using the calculated learned span value and the plurality of stored learned span values. An alert message is generated when the expected learned span value is indicative of a potential future fault of the turbocharger.