Drive control system for hybrid vehicle

A drive control system for a hybrid vehicle, the drive control system comprising:

• an engine,
• a power distribution configured to perform a differential action among a carrier rotated by an engine torque, a sun gear, and a ring gear,
• a braking device that is configured to selectively stop rotation of the carrier,
• a first motor connected to one of the sun gear and the ring gear,
• an output member connected an other of the sun gear and ring gear not connected to the first motor, and
• a second motor configured to generate a drive torque added to a torque of the output member,
• a controller that is configured to:
• establish a first operating mode in which the vehicle is propelled by a torque of the first motor delivered to the output member through the power distribution device while stopping the rotation of the carrier by the braking device, and the torque of the second motor added to the torque of the first motor;
• establish a second operating mode in which the vehicle is selectively powered by one of:
• (i) the second motor alone, and (ii) the engine and the second motor, the second motor being powered indirectly by the engine through the first motor, while allowing the carrier to rotate;
• calculate a time duration from termination of the first operating mode;
• estimate a temperature of the power distribution device based on the calculated time duration;
• enable the first operating mode when the estimated temperature is lower than a predetermined allowable temperature;
• and
• inhibit the first operating mode when the estimated temperature is higher than the allowable temperature.