Control device for hybrid vehicle drive system

A control device for hybrid vehicle drive system controlling a hybrid vehicle drive system which includes a motor generator including a rotor and a stator, the motor generator for driving a vehicle and producing an electric power when reducing speed to apply a regenerative braking force to the vehicle, a front clutch rotatably connecting the rotor and an output shaft of an engine to be selectively engageable, and a multi-stage automatic transmission having an input shaft rotatably connected to the rotor, an output shaft rotatably connected to driving wheels, and a plurality of frictional engagement elements selectively engaged and disengaged for switching a plurality of gear shift stages having gear ratios, each of which is obtained by dividing a rotation speed of the input shaft by a rotation speed of the output shaft, different from one another, the control device for controlling switching operations of an engaged state and a disengaged state of the front clutch and for controlling gear shifting operation of the multi-stage automatic transmission, comprising:

• an engine rotation speed control device performing a rotation speed control of the engine so that a rotation speed of the output shaft of the engine is assumed to be equal to a next gear shift stage input shaft rotation speed obtained by multiplying the rotation speed of the output shaft of the multi-stage automatic transmission by a gear ratio of a next gear shift stage when an operation amount of an accelerator pedal increases from an operation amount smaller than a first predetermined amount, at which the engaged state and the disengaged state of the front clutch is switched, to an operation amount greater than a second predetermined amount, at which gear stages are switched from a current gear shift stage currently established by the multi-stage automatic transmission to the next gear shift stage whose gear ratio is greater than the current gear shift stage, within a priority determining time;
• a front clutch engagement commanding device outputting an engaging command for switching the front clutch from the disengaged state to the engaged state on the basis of a relationship between a rotation speed of the output shaft of the engine increased by the rotation speed control of the engine and a rotation speed of the rotor of the motor generator;
• a front clutch engaging device switching the front clutch from the disengaged state to the engaged state in accordance with the engaging command;
• a release side frictional engagement element releasing device disengaging a release side frictional engagement element which is configured to be engaged when the current gear shift stage is established and configured to be disengaged when the next gear shift stage is established among the plurality of frictional engagement elements when the operation amount of the accelerator pedal exceeds the second predetermined amount;
• a motor generator rotation speed control device performing a rotation speed control of the motor generator to make a rotation speed of the rotor of the motor generator be equal to the next gear shift stage input shaft rotation speed when the release side frictional engagement element is disengaged;
• and
• an engagement side frictional engagement element engaging device establishing an engaged state of an engagement side frictional engagement element which is configured to be a disengaged state when the current gear shift stage is established and is configured to be the engaged state when the next gear shift stage is established among the plurality of the frictional engagement elements for the multi-stage automatic transmission on the basis of a relationship between the rotation speed of the rotor of the motor generator increased by the rotation speed control of the motor generator and the next gearshift stage input shaft rotation speed.