PURPOSE: To provide an automatic transmission control device for a vehicle which extends the operation range during the lock up state of the vehicle, reduce the use frequency of a torque converter, and improve fuel efficiency without hurting driving feelings.
CONSTITUTION: An electronic control device 6 detects the vibration of the output torque of an engine 1 during the specified duration of a cylinder internal pressure sensor 17 and a crank angle sensor 18. The state of the vehicle is determined from the number of rotations of a turbine 33 in a torque converter 3 as well as the velocity of the vehicle. The operation states of the engine 1 and an automatic transmission 1 is determined from the states of the vehicle and operation loads. Then, the lock up region of the torque converter 3 is determined based on the value determined to correct at least one of the quantity of lock up control and lock up operation region of the torque converter 3 depending upon the variation of output torque. This constitution allows the lock up region to be extended and fuel efficiency to be improved without hurting driving feelings.
INOUE HITOSHI
NISHIYAMA RYOJI
WATABE SHINJI
