<div class="htmlview paragraph">Anti-pollution laws establish progressively more stringent standards to reduce emissions from the vehicle fleet. Consequently, car manufacturers are trying to develop more efficient electric and hybrid vehicles.</div> <div class="htmlview paragraph">Nevertheless electric vehicles are not yet competitive compared to internal combustion engine vehicles: looking forward to their future development a considerable reduction of the pollutants could be reached using hybrid propulsion systems.</div> <div class="htmlview paragraph">In this paper a hybrid propulsion system with continuously variable transmission is discussed. A computer model has been used to simulate the hybrid vehicle behaviour during a test cycle and to evaluate the features and the performances of the propulsion system.</div>