System for controlling servo activating hydraulic pressure occurring in vehicular power train

DETAILED DESCRIPTION According to the prevent invention, in order to accomplish the above-mentioned object, a servo activating hydraulic fluid pressure applied to a shifting friction unit is controlled in response to a predetermined variable other than a throttle opening which causes a change in engine output torque from a predetermined pattern of variation of the engine output torque against variation of the throttle opening.
More specifically, according to the present invention, there is provided an accumulator for controlling a rise in servo activating hydraulic fluid pressure applied to a shifting friction unit, a back-up pressure of the accumulator is electromagnetically controlled in response to an output of a control unit supplied with a predetermined variable other than an engine throttle opening which causes a change in engine output torque from a predetermined pattern of variation of the engine output torque against variation of the throttle opening.