Methods and systems are provided for diagnostics of a cylinder valve actuation mechanism in a variable displacement engine (VDE). In one example, during an engine-off condition, the engine may be rotated unfueled, via a starter motor, and a reference exhaust air flow may be estimated. One or more deactivatable engine cylinders may then be deactivated and degradation of the cylinder valve actuation mechanism may be indicated based on a difference between the exhaust air flow following the cylinder deactivation and the reference exhaust air flow.

An internal combustion engine system, including an internal combustion engine (ICE), an exhaust aftertreatment system (EATS) located downstream of said ICE. An exhaust gas recirculation (EGR) pump arranged in an exhaust gas recirculation duct extending between the ICE and EATS, wherein the ICE system has a normal operation mode for transporting, by means of the EGR pump, at least a portion of said exhaust gas to upstream of the ICE. The ICE system further includes a heating device arranged upstream of at least one exhaust aftertreatment devices of said EATS and the ICE system has a pre-heat operation mode for transporting, by means of the EGR pump, exhaust gas and/or air through said heating device and then to said at least one of said exhaust aftertreatment devices.

Methods and systems are provided for controlling engine operation in a hybrid electric vehicle equipped with stop/start capabilities under conditions where requested power or torque is in a hysteresis region between an engine pull up threshold and an engine pull down threshold. In one example, a method comprises obtaining an adjusted engine pull down threshold upon the requested power or torque remaining in the hysteresis region for more than a threshold duration, and commanding the engine deactivated in response to the adjusted engine pull down threshold being equivalent to the requested power or torque. In this way, a motor/generator may be used to meet the requested torque response rather than the engine under such conditions, which may improve fuel economy.

Methods and systems are provided for operating an electric motor to drive either a transmission fluid pump or a direct injection fuel pump. In one example, a method may include operating an electric motor to drive a direct injection fuel pump to supply fuel to a direct injection fuel rail while an engine of a start/stop vehicle is on, and operating the electric motor to drive an auxiliary transmission fluid pump to circulate transmission fluid to a transmission rotationally coupled to the engine while the engine is off during an auto-stop. In this way, the direct injection fuel pump may be electrically driven without increasing vehicle costs through adding an additional electric motor.

A control method of controlling an idle stop-and-go (ISG) function of a vehicle provided with a manual transmission includes: determining, by a controller, whether an ISG function activation condition is satisfied based on vehicle running state information of the vehicle; stopping an engine, by the controller, when the ISG activation condition is satisfied; determining, by the controller, whether a first starting condition in which a shift stage of the manual transmission is a neutral stage is satisfied; determining, by the controller, whether a second starting condition in which a shift stage of the manual transmission is a driving stage is satisfied; and restarting, by the controller, the engine when the first starting condition or the second starting condition is satisfied. The vehicle running state information includes: an operation information of the manual transmission and a clutch pedal, and current and recorded vehicle speeds of the vehicle.

Methods and systems are provided for improving fuel economy and reducing undesired emissions. In one example, a method may include in response to an engine speed being within a first threshold speed of an engine idle speed during a speed reduction request with engine cylinders unfueled, maintaining the cylinders unfueled, and controlling the engine to a desired stopping position responsive to the engine speed being greater than a second threshold speed lower than the idle speed. In this way, fuel usage and emissions may be reduced and engine restart requests may be conducted at least in part via vehicle inertia.

A method and system for operating a vehicle that includes a plurality of engine starting devices and an internal combustion engine is described. In one example, the method determines whether or not to inhibit automatic engine stopping so that a lifespan of an engine starting device may be extended. In one example, the inhibiting is based on a ratio of an actual total number of engine starts generated via the engine starting device to an actual total distance traveled by the vehicle since the engine starting device was installed.

Methods and systems are provided for an aftertreatment system. In one example, a system comprising a spark-ignited engine comprising a selective catalytic reduction device (SCR) arranged in an exhaust passage downstream of a catalyst, and an injector positioned to inject a reductant directly into the exhaust passage downstream of the catalyst subsequent an engine shut-off event.

In a torque-based detection process, a control device detects an excess acceleration state of a vehicle when a duration time of a state in which a value obtained by subtracting a required torque from an actual torque of an internal combustion engine is equal to or greater than a torque threshold value is equal to or greater than a torque determination time. In an acceleration-based detection process, the control device detects the excess acceleration state of the vehicle when a duration time of a state in which a value obtained by subtracting a required acceleration from an actual acceleration of the vehicle is equal to or greater than an acceleration threshold value is equal to or greater than an acceleration determination time.

A vehicle diagnosis system determines whether a vehicle has an abnormality in a temporal engine stop function or a power regeneration function that negates a greenhouse gas reduction effect of the engine. When the vehicle diagnosis system determines an abnormality, the vehicle diagnosis system provides a notification of the abnormality.