DYNAMIC MODEL FOR THE PULL-BELT CVT SIMULATION

Abstract

The continuous variable transmissions (CVT’s) permit to obtain any value of the transmission ratio between two limits. The continuous variation of the transmission ratio can be used to permanently adapt the engine functioning to the actual vehicle's movement conditions, promising important fuel efficiency increase and lower pollutant and CO2 emissions. On the other hand, this type of transmission is not an automatic one by its working principle, which means a change of the vehicle's road load will not automatically adapt the transmission ratio. Due to that inconvenient, extended researches are made today to improve the performances of the CVT’s hydraulic or electric actuation systems, controlled both by mechanical and electronic devices. The CVT's model presented in this paper was designed to represent the base for the study of different controlling algorithms' performances. The authors' intention is to include the CVT's control level in another higher control system of a hybrid propulsion system. Finally, some simulation results are also presented.