Lock-up control system for automatic transmission.

摘要

A lock-up control system for an automatic transmission including a torque converter having an input member and an output member, a multiple stage gear transmission gear mechanism connected with the output member of the torque converter and having a plurality of gear stages and a lock-up clutch for connecting the input member and the output member bypassing the torque converter wherein an engaging force in the lock-up clutch is controllable so as to change the amount of torque transmitted through the lock-up clutch. The system comprises shift detecting device for detecting a shift operation in the transmission mechanism and control device for controlling the engaging force of the torque converter to be maintained at a predetermined value smaller than a fully engaged condition of the lock-up clutch and larger than an entirely released condition of the lock-up clutch when the shift operation is detected by the shift detecting device.