Control device for automatic transmission

Abstract

control device for an automatic transmission (4) having a torque converter (14) with a lock-up clutch (24) provided between an engine (2) and the automatic transmission (4), and a lock-up control device for controlling an engaged condition of the lock-up clutch (24). The control device includes a plurality of different target slip ratio maps each having a plurality of target slip ratio characteristic lines of the lock-up clutch (24) predetermined according to a throttle angle, a first map selector for selecting one of the target slip ratio maps according to a running range, according to whether the running road is a level road / downhill road or an uphill road, and according to a gear position during running in the condition where an accelerator pedal is depressed, and a second map selector for selecting one of the target slip ratio maps according to a running range, according to whether the running road is a level road / uphill road or a downhill road, and according to a gear position during running in the condition where the accelerator pedal is undepressed.

Description

Technical field [0001] The present invention relates to a control device for an automatic transmission, and more particularly, to a control device for an automatic transmission that changes a target slip rate of a lock-up clutch according to a driving state. Background technique [0002] In automatic transmissions for vehicles, a hydraulic lock-up clutch that can mechanically directly connect the output shaft of the engine and the input shaft of the automatic transmission is provided in the torque converter. Generally, the lock-up clutch is locked under certain conditions. Improve the efficiency of the torque converter. [0003] In addition, the lock-up clutch is used to lock the lock-up clutch during deceleration, thereby transmitting the reverse driving force from the drive wheel side to the engine side, suppressing the rapid decrease of the engine speed, so as to restore the predetermined fuel during deceleration. The fuel cut performed up to the rotation speed is maintained f...

AI Technical Summary

Problems solved by technology

[0010] When driving on an uphill road, the driving resistance increases, and it is difficult to accelerate compared with a flat road

Therefore, when running uphill at the target slip rate on a flat road as in the past, the stabilized lockup clutch may generate too much heat and deteriorate durability, so the lockup clutch is disengaged to deal with it. As a result, there is a problem that the fuel consumption on the uphill road deteriorates and drivability deteriorates.

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