Patent ID: 6464617
Filing Date: 2002-10-15
Classification: F16H,Y10T

Abstract:
A shift control method for an automatic transmission including a clutch comprising:determining if a signal for shifting from a reverse range to a drive range is input; determining if an engine is in an idle state when the signal for shifting from the reverse range to the drive range is input; outputting an initial shifting signal of a first duty ratio to a drive unit and maintaining the first duty ratio for a first predetermined fill time when the engine is in the idle state; reducing, when the first predetermined fill time is elapsed, the first duty ratio to a second duty ratio and outputting a signal of the second duty ratio for a soft engagement control to the drive unit; determining if a current turbine rpm is less than a first predetermined value which is obtained by extracting a second predetermined value from a target turbine rpm; outputting, when the current turbine rpm is less than the first predetermined value, a feedback duty control signal to the drive unit; determining if a turbine rpm variation is higher than a third predetermined value or if the turbine rpm is less than a fourth predetermined value; ending, when it is determined that the turbine rpm variation is higher than the third predetermined value or the turbine rpm is less than the fourth predetermined value, the feedback duty control, and after correcting a current duty ratio, outputting an open loop duty control signal to the drive unit; determining if the engine is out of the idle state; determining, when the engine is out of the idle state, if a shifting synchronization is completed; adjusting, when the shifting synchronization is completed, a value of an input throttle opening signal and outputting a duty control signal for increasing the duty ratio to a fifth predetermined value and maintaining the increased duty ratio for a predetermined duration to the drive unit.