Considerations on the operation of inertial continuous variable transmissions

Abstract

The paper focuses on some intrinsic problems of inertial Continuous Variable Transmissions (CVTs). Despite the large number of patents and studies, this kind of CVTs is not currently commercialised. In this paper, some explanations are given on the reason why this type of CVT has not percolated the market. Specifically, different sources of mechanical vibrations which arise in the functioning of these mechanisms are analysed. One example of inertial CVT has been selected to conduct the case study; however the conclusions can be easily extrapolated to other CVTs of the same family. These sources of vibrations are intrinsic to the working principle of this type of transmissions and they cannot be eliminated. Despite of this, some actions in order to mitigate and reduce these vibrations are proposed. To corroborate the results, computational models and real tests have been carried out. The study also demonstrates that the functioning of inertial CVTs depends on the nature of the power plant. That is, inertial CVTs show differences when they are driven either by an electrical motor or an ICE.