Patent ID: 8061463

Claim:
A control system for a hybrid vehicle that comprises an engine, a motor generator and an automatic transmission and that is driven by a driving force being transmitted from at least one of said engine and said motor generator through said automatic transmission to wheels; said control system comprising: a shift controller, which executes an automatic shift control on said automatic transmission in response to a driving condition; and a motor controller, which controls operation of said motor generator; wherein: while said hybrid vehicle is moving along with an accelerator pedal being released from a stepped down condition, if an automatic shifting is executed by said shift controller; then said motor generator is operated in cooperation by said motor controller for bringing an input-side rotational speed of said automatic transmission at a start of the shifting closer to the input-side rotational speed that corresponds to a gear ratio achieved after the shifting, such that in said cooperative operation, a target torque increment ΔTQ is calculated based on a pre- and post-shifting engine rotational speed difference ΔN, and then a target cooperative torque TQco is calculated from the target torque increment, and then the target cooperative torque TQco is compared with an engine friction torque TQEF, and if the target cooperative torque is equal to or smaller than the engine friction torque TQco≦TQEF, then the target cooperative torque TQco is maintained, but if the target cooperative torque is larger than the engine friction torque TQco>TQEF, then the engine friction torque TQEF is set as the target cooperative torque TQco to bring an output torque of the motor generator to this target cooperative torque TQco; and said cooperative operation of said motor generator is executed to bring a total braking torque against said wheels to a value larger than a braking torque of said engine.