Abstract: Method and system for starting an internal combustion engine of a hybrid vehicle, adapted to rotate a drive shaft providing torque via a transmission unit comprising a first clutch connecting the engine to an input shaft of a gearbox connected to a torque converter connected to a second clutch connecting the torque converter to the at least one driving wheel, where the input shaft is connected to an electric machine; the method comprising: disengaging the second clutch to a predetermined torque level such that there is a slip in the second clutch; engaging the lock-up clutch; engaging the first clutch to bring the engine to a first rotational speed; disengaging the first clutch when the engine has reached the first rotational speed; starting the engine, and engaging the first clutch when the engine has started and rotates with a second rotational speed.

Abstract: Method and system for starting an internal combustion engine of a hybrid vehicle, adapted to rotate a drive shaft providing torque via a transmission unit comprising a first clutch connecting the engine to an input shaft of a gearbox connected to a torque converter connected to a second clutch connecting the torque converter to the at least one driving wheel, where the input shaft is connected to an electric machine; the method comprising: disengaging the second clutch to a predetermined torque level such that there is a slip in the second clutch; engaging the lock-up clutch; engaging the first clutch to bring the engine to a first rotational speed; disengaging the first clutch when the engine has reached the first rotational speed; starting the engine, and engaging the first clutch when the engine has started and rotates with a second rotational speed.

Abstract: In a hybrid electric vehicle powered by an internal combustion engine that produces torque and an electric machine that produces torque, a method for operating the electric machine to produce electric assist to the engine includes determining a magnitude of power requested by the vehicle operator, determining a minimum power limit and a maximum power limit of the engine that will produce a response to a torque request within a desired period following the torque request, using the magnitude of power requested, the minimum and maximum power limits of the engine to determine the upper and lower limits of the electric power assist such that the requested torque will be provided within the desired period, and operating the electric machine to provide electric power assist within said upper and lower limits.

Abstract: In a hybrid electric vehicle powered by an internal combustion engine that produces torque and an electric machine that produces torque, a method for operating the electric machine to produce electric assist to the engine includes determining a magnitude of power requested by the vehicle operator, determining a minimum power limit and a maximum power limit of the engine that will produce a response to a torque request within a desired period following the torque request, using the magnitude of power requested, the minimum and maximum power limits of the engine to determine the upper and lower limits of the electric power assist such that the requested torque will be provided within the desired period, and operating the electric machine to provide electric power assist within said upper and lower limits.