Efficiency of Split-Way CVT's. A simplified model

In this paper, a general formula is obtained for the efficiency of all types of Split-Way CVT, consisting of one or two epicyclic trains, a number of fixed ratio gears and one variable speed unit (CVU). It is based on the application of the principle of virtual works and on the simplifying hypothesis that all the dissipation is lumped inside the CVU.

The comparison with some experimental results from the literature shows a surprisingly good fit, also in the neighbourhoods of zero speed ratio.