Abstract
To date the reduced fuel consumption and emissions predicted for CVT vehicles have not been realised by production cars. A contributing factor is that CVT systems have a lower efficiency than their fixed ratio counterparts.
This paper introduces work being undertaken to investigate the low load loss mechanisms in a pushing metal V-belt CVT. A test rig has been developed to accurately measure steady state losses through a CVT at low and no load levels.
This paper gives an overview and discussion of the existing work undertaken on belt drive CVT efficiency, and gives a description of some of the initial modelling work. The experimental work also aims to produce an understanding of the effects of operating temperature on the transmission loss mechanisms, in particular low temperature operation often seen during a cold start have been investigated.
This paper will present details of the test rig, preliminary findings from the experimental work and highlight areas in which improvements to CVT models can be made. It is planned to use the models as the basis for CVT drive cycle simulation work.