Patent ID: 6042506
Filing Date: 2000-03-28
Classification: F16H,Y10T

Abstract:
An automatic transmission control system comprising:a gear change mechanism having an input shaft for receiving an engine rotation force, an output shaft for driving wheels of a vehicle, and frictional engagement elements selectively engageable by hydraulic fluid;engagement switching means for selecting, from the frictional engagement elements, a frictional engagement element, an engagement condition of which is to be switched for a gear down-shift;pressure control means for controlling pressure of the hydraulic fluid to be applied to the selected frictional engagement element; andinitial pressure control means for outputting a control instruction value to the pressure control means for reducing gradually pressure applied to the selected frictional engagement element before rotational speed of the input shaft rises from a control start of the down-shift, the rate of the reduction of the control instruction value being increased with time.