Patent ID: 8715124

Claim:
Powertrain system, comprising: an internal combustion engine and a transmission including first and second torque machines, a planetary gear set, and first, second, and third clutches, wherein the first clutch is configured to couple a first gear element of the planetary gear set to a transmission case ground when applied, the second clutch is configured to couple the first gear element of the planetary gear set to an output member of the first torque machine when applied, and the third clutch is configured to couple an input member of the first torque machine to an output member of the engine when applied; and a control module configured to activate selected ones of the first, second, and third clutches to control operation of the powertrain system in one of a plurality of operating modes, configured to sequentially deactivate the third clutch, activate one of the first and second clutches and deactivate the other of the first and second clutches, and activate the third clutch to effect a transition between a first one of the plurality of operating modes and a second one of the plurality of operating modes.