Patent ID: 6277051
Filing Date: 2001-08-21
Classification: F16H,Y10T

Abstract:
A power-on manual downshift control method comprising the steps of:determining if a power-on manual downshifting operation is being performed or not when a TCU receives a power-on manual downshifting signal;producing a duty control signal of 0% if the power-on manual downshifting operation is being performed;determining if a shift begin point is detected or not;compensating for a feedback start duty ratio Dr, and producing and outputting a compensated duty ratio if the shift begin point is detected;maintaining a state in which the compensated duty ratio is output for a predetermined period of time Ta;executing a feedback control sub-routine on ending of the predetermined period of time Ta;reducing the duty ratio by as much as a predetermined duty amount .DELTA.d on ending of the feedback sub-routine, and maintaining this state for a predetermined period; andending the duty control if the feed back start duty ratio reaches 0%, wherein the feedback control start duty ratio Dr is calculated in accordance with the following equation:Dr=(Dr0+Dr1-Drkd-Drmnl).times.Ke+.DELTA.DtwhereDr is a feedback start duty ratio,Dr0 is an initial standard duty ratio (fixed value stored in memory),Dr1 is a learned compensating rate,Ke is an engine rmp calibration factor,.DELTA.Dt is an oil temperature compensating duty ratio,Drkd is an amount by which a ratio between intake air to engine rpm is less than a preset standard value, andDrmnl is a manual downshift compensating value according to variations in throttle valve opening.