摘要 |
A hydraulic control apparatus for controlling a frictional coupling device of an automatic transmission for a motor vehicle includes a shift valve for effecting an engaging action of the coupling device from a first position to a second position, and an accumulator for reducing a change in a hydraulic pressure applied to the coupling device. The control apparatus is adapted to control a control value to regulate a back pressure of the accumulator, based on a parameter associated with an output of an engine, and according to a predetermined relationship between the control value and the parameter, so as to reduce a shifting shock of the transmission. The control apparatus includes a detector for detecting an engaging time of the engaging action of the coupling device. The control apparatus further includes a compensating device for updating the relationship between the control value and the parameter, depending upon the detected engaging time, with respect to a specific value of the parameter at which the engaging action takes place. The compensating device maintains the updated relationship for use for a subsequent engaging action of the coupling device from the first position to the second position.
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