Patent ID: 6315692
Filing Date: 2001-11-13
Classification: F16H,Y10T

Abstract:
A control apparatus for an automatic transmission of a vehicle, said transmission having a plurality of hydraulic engaging elements for speed changing, said apparatus comprising:a plurality of speed-change control valves corresponding to said hydraulic engaging elements;a plurality of speed-change solenoid valves corresponding to said speed-change control valves, wherein a hydraulic oil pressure in each of said hydraulic engaging elements is adjusted depending on a signal pressure from a corresponding speed-change solenoid valve with a line pressure from a hydraulic oil pressure source serving as a base pressure; andcontrol means for varying, at a time of non-speed-changing, an opening degree of a speed-change solenoid valve corresponding to a predetermined speed-change control valve which corresponds to a hydraulic engaging element of a then-established speed transmission train, said opening degree being varied within a range in which there is outputted a signal pressure higher than a minimum signal pressure required to fully open said predetermined speed-change control valve.