Method of controlling automatic transmission shift pressure

Claim 3

A method as recited in claim 1 further comprising the steps of: sensing the actual transmission gear ratio; comparing the actual sensed transmission gear ratio to the desired gear ratio; and stopping the changing of the actual transmission shift pressure when the actual sensed transmission gear ratio is the same as the desired transmission gear ratio.

Claim 4

A method as recited in claim 1 further comprising the steps of: sensing the actual transmission gear ratio; comparing the actual sensed transmission gear ratio to the desired transmision gear ratio; detecting a difference between the actual sensed transmission gear ratio and the desired transmission gear ratio; selecting a second function of the combination of the first function and time; changing the actual transmission shift pressure in accordance with the second function; sensing the actual transmission gear ratio; comparing the actual sensed transmission gear ratio to the desired transmission gear ratio; performing the changing, sensing, comparing steps until the actual sensed transmission gear ratio is the same as the desired transmission gear ratio; and storing a function of the actual transmissions shift pressure and transmission input torque capacity pressure corresponding to the point when the actual and the desired transmission gear ratios are the same.

Claim 5

A method as recited in claim 3 wherein the step of changing the actual transmission shift pressure includes the steps of: calculating a first solenoid duty cycle as a function of transmission input torque capacity pressure; and applying the first solenoid duty cycle to a valve means controlling the actual transmission shift pressure.

Claim 6

A method as recited in claim 4 further comprising the steps of: calculating a second solenoid duty cycle which is a function of the first solenoid duty cycle and time; and applying the second solenoid duty cycle to the valve means controlling the actual transmission shift pressure.

Claim 7

A method as recited in claim 5 wherein the second duty cycle function is a piecewise linear function with increasing slope having a maximum limit.

Claim 8

A method as recited in claim 5 wherein the step of storing a function of the actual transmission shift pressure and transmission input torque capacity pressure includes storing the actual transmission shift pressure magnitude corresponding to transmission gear shifts.

Claim 9

A method as recited in claim 7 further comprising the step of: delaying a period of time, after at least one step of changing the actual transmission shift pressure to achieve the selected predetermined ratio, the step of sensing the actual transmission gear ratios so that the hydraulic transmission has time to respond.

Claim 10

A method as recited in claim 7 wherein the step of storing further includes generating a first transmission shift pressure for upshifts between two transmission gears and a second transmission shift pressure for downshifts between the same two gears.

Claim 11

A method as recited in claim 9 wherein the transmission shift pressures for upshifts and downshifts between the same transmission gears are separated by a constant magnitude pressure.