MODELLING AND IDENTIFICATION OF AN ELECTRO-HYDRAULIC PUSH-BELT CVT SYSTEM

Calibration development of CVT-equipped vehicles has historically been conducted using extensive vehicle testing with very limited analytical analysis of the effect of calibration changes. Simulation of the CVT system behaviour in a vehicle offers a distinct benefit in the calibration process but this requires a validated model of the CVT system ratio response. This paper presents a suitable CVT system model. The model architecture reflects the physical construction of the CVT itself, with individual submodels representing the variator, the hydraulics unit and the electronic controller. Extensive system identification experimental testing was conducted, the results of which were used to characterise the behaviour of the CVT hydraulic unit and variator. A second set of experimental tests was conducted to demonstrate the validity of the CVT model, and a good correlation is demonstrated.