Shift dynamics modelling for optimisation of variator slip control in a pushbelt CVT

Efficiency improvement of the pushbelt CVT by reducing variator clamping forces is well established. The increased risk of gross belt slip calls for novel approach, including direct control of belt slip. First attempts led to promising results in steady state conditions, but unacceptable slip occurred during fast shifting events. In this work theoretical variator shift models are validated. Results are used for model optimisation of the variator shift dynamics, leading to an optimised CVT slip controller. Results of the experiments after implementation in a test vehicle are presented. A comparison is made to the results obtained with the previous controller.