Patent ID: 6859709

Claim:
A system for enhanced ratio control in a continuously variable transmission (CVT) including a ratio control element positionable by an actuator in response to an actuator command to establish various CVT ratios in the CVT, the system comprising: a measured CVT ratio generator obtaining information of an actual CVT ratio established in the CVT to give a measured value of CVT ratio; a filter processing the measured value of CVT ratio in a manner to refine the information of the actual CVT ratio to give an estimated value of CVT ratio; a command generator determining the actuator command such that the actuator command remains unaltered when a deviation of the estimated value of CVT ratio from a desired value of CVT ratio stays within a dead zone; and a filter and command generator manager narrowing the dead zone to meet precision requirement upon determination that the desired value of CVT ratio has been accomplished and adjusting the filter to gain requirement for keeping the magnitude of signal at frequency of noise within the narrowed dead zone.