Hybrid powertrain for vehicles

A powertrain for a vehicle, the powertrain comprising:

• an engine input shaft selectively connectable to an engine by a main clutch;
• a motor input shaft mounted to be coaxial with the engine input shaft and engaged to a motor;
• a center synchronizer mounted to selectively connect the engine input shaft to the motor input shaft;
• a first output shaft and a second output shaft each mounted parallel to the engine input shaft;
• a variable driving gear mounted on the motor input shaft to maintain or increase a rotation speed of the motor input shaft and then to transmit the maintained or increased rotation speed to the first output shaft;
• and
• a plurality of gear pairs mounted to form different transmission gear ratios between the engine input shaft and the first output shaft and between the engine input shaft and the second output shaft,
• wherein a plurality of transmission gear ratios, formed by the plurality of gear pairs, and two transmission gear ratios, formed when the variable driving gear transmits power to the first output shaft, form a series of the different transmission gear ratios used to drive the vehicle.