At least some embodiments of the present disclosure are directed to systems and methods for controlling a cylinder deactivation (CDA) operation for an electrified powertrain, the electrified powertrain comprising an engine and an additional power source, the engine having a plurality of cylinders. The method includes the step of: operating the electrified powertrain in a CDA mode and deactivating one or more selected cylinders of the plurality of cylinders; receiving measurement data indicative of operating conditions of the electrified powertrain; analyzing the measurement data to determine whether a predetermined operating condition is met; and adjusting the CDA operation by adjusting the duration of the CDA operation or changing a number of deactivated cylinders.

A vehicle drive system includes an internal combustion engine, a clutch, an engine rotation speed detector, an output shaft rotation speed detector, and a processor. The internal combustion engine includes cylinders and a crankshaft. The clutch is connected to the crankshaft via a torsion element and includes an output shaft. The engine rotation speed detector detects a crankshaft rotation speed. The output shaft rotation speed detector detects an output shaft rotation speed. The processor is configured to calculate a torque generated in each of the cylinders based on the crankshaft rotation speed. The processor is configured to decrease transmission torque of the clutch so that a difference between the crankshaft rotation speed and the output shaft rotation speed to be a target value when misfiring occurs. The processor is configured to identify a misfiring cylinder among the cylinders based on the torque calculated while the transmission torque is decreased.

A vehicle and method for controlling a vehicle having a variable displacement engine with an auxiliary machine connected directly to the engine crankshaft and to an energy storage device includes switching from a cylinder disablement (VDE) mode to a normal mode when the torque demand and engine speed lie outside an outer range defined by a first threshold (T.sub.out), and switching from the normal mode to the VDE mode when the torque demand and engine speed lie within an inner range, which lies within the outer range and defined by a second threshold (T.sub.in). When operating in a band between the two thresholds, the auxiliary machine draws energy from the energy storage device and supplements the output torque from the engine if operating in the VDE mode, and derives torque from the engine crankshaft to recharge the energy storage device if operating in the normal mode.

At least some embodiments of the present disclosure are directed to systems and methods for controlling a cylinder deactivation (CDA) operation for an electrified powertrain, the electrified powertrain comprising an engine and an additional power source, the engine having a plurality of cylinders. The method includes the step of operating the electrified powertrain in a CDA mode and deactivating one or more selected cylinders of the plurality of cylinders; receiving measurement data indicative of operating conditions of the electrified powertrain; analyzing the measurement data to determine whether a predetermined operating condition is met; and adjusting the CDA operation by adjusting the duration of the CDA operation or changing a number of deactivated cylinders.

At least some embodiments of the present disclosure are directed to systems and methods for controlling a cylinder deactivation (CDA) operation for an electrified powertrain, the electrified powertrain comprising an engine and an additional power source, the engine having a plurality of cylinders. The method includes the step of: operating the electrified powertrain in a CDA mode and deactivating one or more selected cylinders of the plurality of cylinders; receiving measurement data indicative of operating conditions of the electrified powertrain; analyzing the measurement data to determine whether a predetermined operating condition is met; and adjusting the CDA operation by adjusting the duration of the CDA operation or changing a number of deactivated cylinders.

At least some embodiments of the present disclosure are directed to systems and methods for controlling a cylinder deactivation (CDA) operation for an electrified powertrain, the electrified powertrain comprising an engine and an additional power source, the engine having a plurality of cylinders. The method includes the step of operating the electrified powertrain in a CDA mode and deactivating one or more selected cylinders of the plurality of cylinders; receiving measurement data indicative of operating conditions of the electrified powertrain; analyzing the measurement data to determine whether a predetermined operating condition is met; and adjusting the CDA operation by adjusting the duration of the CDA operation or changing a number of deactivated cylinders.

Methods and systems are provided for diagnosing whether one or more intake air oxygen sensors positioned in an intake of an engine of a vehicle, are functioning as desired. In one example, a method comprises injecting fuel into one or more cylinders of the engine without combustion, routing un-combusted hydrocarbons from the one or more cylinders to the intake via a crankcase ventilation system, and indicating whether the one or more intake air oxygen sensors are functioning as desired based on a response of the one or more intake air oxygen sensors. In this way, the one or more intake air oxygen sensors may be periodically diagnosed which may improve engine operation, and reduce engine degradation, particularly with regard to hybrid electric vehicles with limited engine run-time.

Methods and systems are provided for diagnosing whether one or more intake air oxygen sensors positioned in an intake of an engine of a vehicle, are functioning as desired. In one example, a method comprises injecting fuel into one or more cylinders of the engine without combustion, routing un-combusted hydrocarbons from the one or more cylinders to the intake via a crankcase ventilation system, and indicating whether the one or more intake air oxygen sensors are functioning as desired based on a response of the one or more intake air oxygen sensors. In this way, the one or more intake air oxygen sensors may be periodically diagnosed which may improve engine operation, and reduce engine degradation, particularly with regard to hybrid electric vehicles with limited engine run-time.

A vehicle and method for controlling a vehicle having a variable displacement engine with an auxiliary machine connected directly to the engine crankshaft and to an energy storage device includes switching from a cylinder disablement (VDE) mode to a normal mode when the torque demand and engine speed lie outside an outer range defined by a first threshold (T.sub.out), and switching from the normal mode to the VDE mode when the torque demand and engine speed lie within an inner range, which lies within the outer range and defined by a second threshold (T.sub.in). When operating in a band between the two thresholds, the auxiliary machine draws energy from the energy storage device and supplements the output torque from the engine if operating in the VDE mode, and derives torque from the engine crankshaft to recharge the energy storage device if operating in the normal mode.

Systems and methods for operating a driveline of a hybrid vehicle are disclosed. In one example, an engine may enter or stay in one of two cylinder modes in response to a request to a negative torque capacity of an electric machine being insufficient to provide a desired driveline braking torque. One cylinder mode operates cylinders with cylinder valves held closed and without fuel being injected to the cylinders while the other cylinder mode operates cylinders with valves that open and close without fuel being injected to the cylinders.