METHOD FOR CONTROLLING AUTOMATIC TRANSMISSION

PROBLEM TO BE SOLVED: To provide a method for controlling an automatic transmission for determining synchronization of an input shaft and an output shaft accurately without causing delay in time even when rotational speed of the output shaft cannot be detected, shortening speed change operation time, and reducing mechanical shock caused by fitting operation. SOLUTION: In this method for controlling the automatic transmission provided with a gear speed change mechanism, an operation mechanism composed of a shift and select part, a friction part, and a meshing part, an input shaft rotational speed detection means, an output shaft rotational speed detection means, an advance situation detection means, and a controller to drive friction and engagement operation before the input shaft and the output shaft are synchronized at speed change operation time and drive meshing and engagement operation after they are synchronized, the controller has an acceleration computing means for obtaining acceleration A from rotational speed NI of the input shaft and determines that they are synchronized when the obtained acceleration A is reduced below a predetermined synchronization determining value EA after the obtained acceleration A exceeds a predetermined determination start value TA when rotational speed NO of the output shaft cannot be detected. COPYRIGHT: (C)2008,JPO&INPIT