Prediction of CVT Transmission Efficiency by Metal V-Belt and Pulley Behavior with Feedback Control 2010-01-0855

A simulation technology has been developed to predict the transmission efficiency of a metal pushing V-belt and pulleys that make up the drive system of a continuously variable transmission (CVT).

When a CVT operates in an actual vehicle, pulley thrust pressure is adjusted by feedback control to maintain a speed ratio. This feedback control has been implemented, for the first time, in an existing simulation that predicts the dynamic behavior of a metal V-belt using explicit structural analysis. The new simulation enables stable control of a target speed ratio when appropriate gains are set for each analysis condition. Using this simulation, the following values can be obtained: 1) pulley thrust pressure that is necessary for maintaining a specified speed ratio but could previously be derived only from physical testing, 2) transmission efficiency of a CVT drive system, consisting of a metal pushing V-belt and pulleys, at each operating condition, and 3) belt friction losses calculated from sliding velocities and friction forces applied to element contact surfaces.