Patent ID: 7713166

Claim:
A method for controlling the operation of a continuously variable transmission (CVT) having hydraulically operated primary and secondary pulleys with varying effective diameters, and a drive belt coupling the primary pulley to the secondary pulley, comprising: providing a programmable controller; providing an algorithm or map associated with said controller, wherein said algorithm or map determines clamping pressure and/or differential pressure level between said pulleys in said CVT for achieving a desired rate of change in ratio in said CVT; providing a hydraulic servo control system adapted for control by said programmable controller and for control of clamping pressure and/or differential pressure between pulleys in said CVT; providing a pressure pump fluidly connected to said secondary pulley; wherein said pressure pump has a bypass control valve that opens at low pressures; and providing a shift pump fluidly connected to said primary pulley; wherein said shift pump is fluidly connected to said pressure pump.