Method and apparatus for controlling a shift in a multi-mode powertrain system

A method for controlling a multi-mode transmission in response to a command to execute a shift between a first electrically-variable transmission (EVT) range and a second EVT range, comprising:

• transitioning the multi-mode transmission to operating with three speed degrees of freedom;
• controlling torque output from a first torque machine coupled to the transmission in response to an output torque request;
• controlling speed of a second torque machine coupled to the transmission to synchronize speed of an oncoming clutch associated with the second EVT range and coincidentally controlling speed of the first torque machine and controlling speed of an engine coupled to the transmission to achieve a preferred speed of an output member of the transmission;
• activating the oncoming clutch upon synchronizing the speed of the oncoming clutch;
• and then
• operating the transmission in the second EVT range responsive to the output torque request.

A method for operating a powertrain system including a multi-mode transmission configured to transfer torque among first, second, and third independently controlled torque actuators and an output member, comprising:

• transitioning the multi-mode transmission to operate with three speed degrees of freedom;
• controlling speed of one of the torque actuators to synchronize speed of an oncoming clutch associated with a target transmission range and coincidentally controlling speeds of the two other torque actuators to achieve a preferred speed of the output member of the transmission, controlling torque output from said one of the torque actuators in response to an output torque request, and activating the oncoming clutch upon synchronizing the speed of the oncoming clutch;
• and then
• operating the multi-mode transmission in the target transmission range and controlling the first, second, and third independently controlled torque actuators in response to the output torque request.