Patent ID: 7959535

Claim:
A controller for a vehicle power transmission system that transmits power of an engine to a drive wheel, comprising: an electric differential unit that allows controlling a differential state between a rotational speed of an input shaft coupled to the engine and a rotational speed of an output shaft by controlling an operating state of an electric motor coupled to a rotating element of a differential mechanism; a transmission unit that is arranged in a power transmission path between the electric differential unit and the drive wheel; and an engine upper limit setting device that, when the transmission unit is shifting speeds, and a rotational speed of the engine increases because of torque reduction control by the electric motor, prelimits an upper limit of the rotational speed of the engine to a value, at which the rotational speed of the engine is prevented from reaching a high rotational speed region during the torque reduction control, from a start of shifting through a start of the torque reduction control, wherein a determination as to whether the engine upper limit setting device switches the upper limit is made on a basis of a torque reduction amount required at a time when the transmission unit shifts speeds.