A powertrain system including an internal combustion engine rotatably coupled to a variator of a continuously variable transmission (CVT) is described. A method for controlling the CVT includes determining a first speed ratio change rate based upon a desired speed ratio and a commanded speed ratio, and determining a commanded speed ratio trajectory based upon the first speed ratio change rate, an actual speed ratio and a commanded speed ratio. A ratio change coefficient and a force ratio factor are determined based upon the commanded speed ratio trajectory. A shift force is determined based upon the ratio change coefficient and a total speed ratio change rate. A primary pulley pressure and a secondary pulley pressure for the CVT are controlled based upon the shift force and the force ratio factor.

A method for controlling a state of a drive train of a power train including at least one motive power source and a set of couplers and reducers of which respective engagements define a plurality of states of the drive train, by engagement of one or a plurality of energy sources in provision of torque and by the ratio of transmission of same to wheels. States targeted from a current state are ranked in real time on the basis of the difference between the motive force available in a current state and in each target state.