Method and apparatus to control a continuously variable transmission

摘要

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 desired variator speed ratio in response to a change in an operator input and executing a step-upshift in the CVT based upon the desired variator speed ratio. The step-upshift includes determining a preferred CVT input deceleration profile based upon the desired variator speed ratio, a present variator speed ratio, and a preferred shift time and synchronizing the preferred CVT input deceleration profile with a command to reduce engine torque. A change rate for the variator speed ratio is based upon the preferred CVT input deceleration profile, and the CVT is controlled in response to the change rate for the variator speed ratio and the desired variator speed ratio.

主权项

1. A method for controlling a continuously variable transmission (CVT) of a powertrain system including an internal combustion engine coupled to an input member of the CVT, the method comprising:
determining a desired variator speed ratio in response to a change in an operator input; and executing a step-upshift based upon the desired variator speed ratio, the step-upshift including:
determining a preferred CVT input deceleration profile based upon the desired variator speed ratio, a present variator speed ratio, and a preferred shift time,synchronizing the preferred CVT input deceleration profile with a command to decrease engine torque,determining a change rate for the variator speed ratio based upon the preferred CVT input deceleration profile, andcontrolling the CVT in response to the change rate for the variator speed ratio and the desired variator speed ratio.