Patent ID: 6971968

Claim:
A transmission control system for a hybrid vehicle, comprising: a hybrid transmission comprising a differential mechanism which includes at least four rotating members, rotating conditions of all of the rotating members being determined when rotating conditions of two of the rotating members are determined, four of the rotating members being connected to one of two motor/generators, an input connected to a prime mover, an output connected to a driveline, and the other of the motor/generators, the one of the motor/generators being controlled by means of a revolution speed control to execute a transmission ratio control, the other of the motor/generators being controlled by means of a torque control to execute an output control; and a controller connected to the hybrid transmission including the motor/generators, the controller being arranged to change the torque control of the motor/generator under the torque control to the revolution speed control and to change the revolution speed control of the other motor/generator under the revolution speed control to the torque control, when one of the torque of the motor/generator under the revolution speed control and the revolution speed of the other motor/generator under the torque control becomes saturated, wherein the controller determines that the torque of the motor/generator under the revolution speed control becomes saturated when the torque detected by a torque detector becomes out of a range between upper and lower torque limits of the motor/generator under the revolution speed control, and wherein the controller determines that the revolution speed of the motor/generator under the torque control becomes saturated when the revolution speed detected by a revolution speed detector becomes out of a range between upper and lower revolution speed limits of the motor/generator under the torque control.