Patent ID: 6254512
Filing Date: 2001-07-03
Classification: B60W,F16H,Y10T

Abstract:
A hydraulic control apparatus of an automatic transmission having pressure-adjust command generating means for changing a transmission speed by engaging and disengaging a specified friction coupling device in said automatic transmission connected to an engine, and adjusting an oil pressure acting on said friction coupling device when changing the transmission speed, comprising:speed change command signal generating means for generating a speed change command signal representing a speed change ratio of the automatic transmission;transmission output shaft revolution speed detector means for detecting a revolution speed of an output shaft of said automatic transmission;transmission input shaft revolution speed detector for detecting a revolution speed of an input shaft of said automatic transmission;revolution ratio calculating means for calculating an actual revolution ratio between said input and output shafts of said automatic transmission on the basis of the detected revolution speeds of said input and output shafts;target revolution ratio setting means for one of storing and calculating a target revolution ratio between said input and output shafts of said automatic transmission, andoil pressure correction value calculating means for correcting an oil pressure acting on said friction coupling device so that said actual revolution ratio follows up said target revolution ratio after the speed chance command signal is generated and before actual shifting operation starts in response to said speed chance command signal.