| 摘要 |
PCT No. PCT/JP87/00441 Sec. 371 Date Feb. 22, 1988 Sec. 102(e) Date Feb. 22, 1988 PCT Filed Jun. 30, 1987 PCT Pub. No. WO88/00307 PCT Pub. Date Jan. 14, 1988.In an automatic transmission equipped with a lock-up clutch (6) capable of transmitting engine power to the automatic transmission (1) directly or via a torque converter (2), the automatic transmission has sensors (11, 12) for detecting an input rotational speed and an output rotational speed of the transmission, a control system including a shift start determination step (66) for judging start of a shift by comparing a ratio of the input rotational speed to the output rotational speed with a gear ratio prevailing prior to a shift and a shift end determination step (68) for judging end of a shift by comparing the ratio of the input rotational speed to the output rotational speed with a gear ratio prevailing after a shift, and a lock-up solenoid (10) responsive to output signals from the shift start determination step and shift end determination step for releasing the lock-up clutch (6) during a shift. Thus, proper control of the lock-up clutch at the time of a gear shift can be carried out even in the same type of transmission and even under all shift conditions, and shock such as racing of the engine or a shift executed with the lock-up clutch in the engaged state can be prevented. |
