POWER TRAIN WITH A VARIABLE-SPEED TRANSMISSION AND MOTOR VEHICLE OF HYBRID TYPE USING SUCH A POWER TRAIN

The present invention relates to a powertrain for a motor vehicle comprising a thermal engine (), a variable-speed transmission device () including an engine epicyclic gear train () with a sun gear () carried by a hollow shaft () and a crown gear () carried by a hollow shaft () surrounding hollow shaft () of the sun gear, the sun gear and the crown gear are each connected to shaft () of thermal engine () by a controlled clutch ( and ) and to a fixed part () of the vehicle by a one-way clutch ( and ), and a track ( and ) for motion transmission to a drive axle (). According to the invention, the powertrain comprises a controlled connection () between the two hollow shafts ( and ).