Method of detecting torque phase start in clutch to clutch speed shift of vehicular automatic transmission, method of detecting torque interference intensity and shift control apparatus of vehicular automatic transmission

摘要

To relatively precisely detect the start of torque phase for relatively precisely restraining speed shift shock caused by torque interference in clutch to clutch speed shift, an output from an input shaft rotational speed sensor at a reduction gear unit is passed through a secondary Butterworth high pass filter which is a digital filter having a cutoff frequency of 1.0 Hz to remove a change component caused by acceleration of the vehicle. A filter output Ni_fil which is a change component by generation of transmission torque of an engaged side clutch is thus provided. When this filter output Ni_fil falls to less than a first threshold value of -ref1 and thereafter becomes less than a second threshold value of -ref2 without recovering to be equal to or higher than the first threshold value of -ref1, it is determined to be the start of the torque phase.