A hybrid vehicle drive system including (a) an engine, (b) an electric
motor, (c) a planetary gear device having a first rotary element
connected to the engine, a second rotary element connected to the
electric motor and connected through a first clutch to an output member
connected to vehicle drive wheel, and a third rotary element connected
through a second clutch to the output member, (d) a forward motor drive
control device for engaging the first clutch and releasing the second
clutch to thereby establish a forward motor drive mode in which the
vehicle is driven in a forward direction by the electric motor, (e) a
forward-engine-drive control device for engaging at least the second
clutch to establish an engine-drive mode in which the vehicle is driven
in the forward direction by the engine, and (f) a second-clutch control
device operable upon switching of a vehicle drive mode from the forward
motor drive mode to the forward engine drive mode, for engaging the
second clutch only after the engine speed has exceeded the motor speed.