A method for operating a drive system having at least one drive engine for a motor vehicle, having the following: carrying out an acceleration monitoring of the motor vehicle, a changeover to an alternative monitoring being made when the acceleration monitoring can no longer carry out a reliable monitoring, and, in the alternative monitoring, an engine rotational speed being limited to a maximum permissible engine rotational speed; and ascertaining the maximum permissible rotational speed as a function of a rotational speed specification specified by a driver's request.

Methods and systems for driving vehicle accessories of a vehicle that includes an automatic transmission are presented. In one non-limiting example, the vehicle accessories are driven via a vehicle's kinetic energy while an engine of the vehicle has stopped rotating. Vehicle accessories are driven from a location of a driveline downstream of a torque converter impeller.

A start control device for an engine includes an engine control unit, a motor control unit, and a control unit which controls the engine control unit and the motor control unit, wherein the control unit, when transferring an engine restart control mode from a motoring control state to a fuel combustion control state, executes the transfer via a motor/engine combined control state, and sets the timing of transferring from the motoring control state to the motor/engine combined control state, to a timing at which a crank angle of a cylinder where fuel is combusted first after starting fuel injection reaches a crank angle at which it is estimated that torque is generated by the first combustion of fuel in the cylinder.

Methods and systems are provided for diagnosing whether active engine mounts configured to isolate engine vibration from a cabin and chassis of a vehicle are functioning as desired. In one example, engine vibrations are actively induced, and the active engine mounts are alternately controlled to a first, dampening mode, and to a second, stiffening mode for predetermined time periods, where resultant chassis vibrations are monitored during the predetermined time periods. By monitoring chassis vibrations as a function of induced engine vibrations, and further responsive to the active engine mounts being controlled to the first and second modes, it may be indicated as to whether the active engine mounts are functioning as desired.

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 deactivation modes or enter or stay in a combustion mode in response to a request to downshift a transmission while a vehicle in which the engine resides is coasting.

Methods and systems are provided for diagnosing whether active engine mounts configured to isolate engine vibration from a cabin and chassis of a vehicle are functioning as desired. In one example, engine vibrations are actively induced, and the active engine mounts are alternately controlled to a first, dampening mode, and to a second, stiffening mode for predetermined time periods, where resultant chassis vibrations are monitored during the predetermined time periods. By monitoring chassis vibrations as a function of induced engine vibrations, and further responsive to the active engine mounts being controlled to the first and second modes, it may be indicated as to whether the active engine mounts are functioning as desired.

Methods and systems are provided for operating a driveline of a hybrid vehicle that includes an internal combustion engine, an electric machine, and a transmission are described. In one example, the engine is started and coupled to the driveline via closing a clutch of a dual clutch transmission. Speed of the engine and clutch pressure are controlled to reduce driveline torque disturbances and provide a desired wheel torque.

Methods and systems are provided for launching a vehicle in an electric-only mode of operation. In one example, a driveline operating method comprises engaging a parking pawl to an output shaft of a dual clutch transmission in response to a request to engine a vehicle into a parked state, and disengaging the parking pawl via rotating an engine via an integrated starter/generator in response to a request to propel the vehicle solely via power of an electric machine positioned downstream of the dual clutch transmission. In this way, the vehicle may be launched in the electric-only mode without activating the engine in a fueled mode of operation and then deactivating the engine, which may increase vehicle operator satisfaction and which may improve fuel economy.

Methods and systems are provided for operating a driveline of a hybrid vehicle powertrain, where the driveline includes an electric machine downstream of a dual clutch transmission, which is downstream of an engine. In one example, a method comprises communicating from a transmission, a torque to accelerate transmission components from a first speed to a second speed with first and second clutches of a dual transmission open, the communicating performed while an electric machine coupled to the dual clutch transmission at a location downstream of the dual clutch transmission is providing torque to propel a vehicle. In this way, wheel speed may remain substantially constant while the transmission is shifted and the engine is stopped.

Methods and systems are provided for controlling clutch capacity in a hybrid electric vehicle. In one example, a method includes adjusting values of a transfer function of a clutch of a dual clutch transmission in response to an operating condition of an engine and/or operating condition of an integrated starter/generator coupled to the engine while a vehicle is propelled via an electric machine coupled to the dual clutch transmission, and maintaining a driver demand wheel torque at vehicle wheels via adjusting torque of the electric machine in response to the operating condition of the engine and/or operating condition of the integrated starter generator. In this way the method may apply pressure to one of the clutches where engine speed is independently controlled to maintain positive or negative slip, thus enabling adaptation of positive and negative clutch transfer functions, which may improve driveline operation and shift quality.