Abstract: The present invention provides a method and apparatus for mathematically calculating an optimal transmission input torque value for the inertia phase and the torque phase of a ratio change. Engine output is then altered by an amount necessary to change the actual value of the transmission input torque to the calculated optimal value of transmission input torque. The timing of the clutch elements during the power-on skip through neutral downshift is established by calculating delay periods for the off-going and on-coming clutches such that a predetermined desired shift time is met. The power-on skip through neutral downshift is thereafter adaptively controlled so that aberrations are diagnosed and corrected during subsequent downshifts. The invention is carried out by monitoring engine and/or transmission characteristics including input speed, output speed and shift duration during a downshift and identifying departures from acceptable patterns.

Abstract: The present invention provides a method and apparatus for mathematically calculating an initial value of an adaptive parameter and thereafter adaptively controlling a power-on downshift in an automatic transmission wherein a transmission aberration during a shift is diagnosed and corrected during subsequent power-on downshifts. The invention is carried out by monitoring transmission characteristics including input speed, output speed and shift duration during a power-on downshift, and identifying departures from acceptable patterns. Each type of departure calls for a particular remedy, and a suitable adjustment is calculated based on the times and/or the commanded pressures at certain times, the adjustment being implemented by changing one or more initial conditions for the next shift of the same type. The adjustments may have to be large to make a full or significant partial correction at the next shift. Conversely small increments may be necessary to avoid over-correction.

Abstract: The present invention provides a method and apparatus for adaptively controlling a closed throttle downshift in an automatic transmission wherein a transmission aberration during a shift is diagnosed and corrected during subsequent closed throttle downshifts. The invention is carried out by monitoring transmission characteristics including input speed, output speed and shift duration during a closed throttle downshift, and identifying departures from acceptable patterns. Each type of departure calls for a particular remedy, and a suitable adjustment is calculated based on the times and/or the commanded pressures at certain times, the adjustment being implemented by changing one or more initial conditions for the next shift of the same type. The adjustments may have to be large to make a full or significant partial correction at the next shift. Conversely small increments may be necessary to avoid over-correction.

Abstract: A method for adaptively learning clutch volumes and fill level to compensate for build tolerances and clutch wear includes increasing a fill level of a clutch during an oncoming fill phase of a clutch to clutch transmission. A state of a regulator valve of the clutch to clutch transmission is monitored during the oncoming fill phase. Fill level of the clutch is adjusted before a next shift based on whether the regulator valve switches from a regulating state to a full feed state before elapse of a valid shift time.