Abstract
The fundamental features of belt type CVT's can be identified with their admissible power, their ?width" (ratio of highest to lowest speed ratio), their mechanical efficiency and their power-to-size ratio. By combining one variator and one or more epicyclic trains into some complex arrangement, it is possible to amplify either power or width and reduce the complementary parameter, width or power, in comparison with the single variator. Combinations of two or more split way configurations (two-or multi-mode schemes), where the ?modes" are commuted by brakes and/or friction clutches, can improve both power and width. We will here consider several possible schemes for the automotive application, in view of increasing the engine power class for assigned variator and the width of the simple variator up to include neutral and/or reverse, with particular concern for the best efficiency and the drive size control.