Drive control system for hybrid vehicle

A drive control system for a hybrid vehicle,

• the drive control system comprising:
• a power split mechanism including a carrier, a sun gear and a ring gear as rotating elements, the power split mechanism being configured to carry out differential action, a torque output from an engine being transmitted to the carrier;
• a brake mechanism configured to selectively stop rotation of the carrier;
• a first motor coupled to one of the sun gear and the ring gear, the first motor being able to generate an electric power;
• an output member coupled to the other one of the sun gear and the ring gear;
• a second motor configured to add a driving torque for propelling the hybrid vehicle to a torque of the output member;
• and
• an electronic control unit configured to
• obtain at least one of a first time that is a duration of a motor driven state or a second time that is a duration of a state where the motor driven state is ended,
• estimate a temperature of the power split mechanism based on at least one of the first time or the second time, and
• allow or inhibit the motor driven state in accordance with following condition i) and condition ii) or following condition i) and condition iii),
• i) allow the motor driven state when a first temperature is lower than a predetermined first threshold or when a second temperature is lower than a predetermined second threshold, the first temperature being a temperature of the power split mechanism, estimated based on the first time, the second temperature being a temperature of the power split mechanism, estimated based on the second time,
• ii) allow the motor driven state when the first temperature is higher than or equal to the first threshold and the first time is shorter than or equal to a predetermined first reference time, and inhibit the motor driven state when the first temperature is higher than or equal to the first threshold and the first time exceeds the first reference time,
• iii) allow the motor driven state when the second temperature is higher than or equal to the second threshold and the second time is longer than or equal to a predetermined second reference time, and inhibit the motor driven state when the second temperature is higher than or equal to the second threshold and the second time is shorter than the second reference time, wherein
• the motor driven state is a state that satisfies all the following conditions iv) to vi),
• iv) rotation of the carrier is stopped by the brake mechanism,
• v) a torque output from the first motor is transmitted to the output member via the power split mechanism, and
• vi) the second motor is outputting the driving torque.