A parallel-hybrid drive-train for propulsion of a small scooter

The paper presents the results of a two year study regarding the use of an innovative drive-train, having a parallel-hybrid structure, in a small scooter, in which a conventional internal combustion engine is coupled with an electric motor for the vehicle propulsion. The developed architecture enhances the maximum vehicle power, by exploiting the braking energy (by recovering it into the provided electrochemical accumulator), and operating the vehicle in zero emission mode for limited ranges. Moreover, it allows for recharging the inner battery from the electric mains, which is extremely appealing in terms of operating costs. According to the simulation results, the hybridization is able to enhance the maximum power of the scooter by 1.1 kW (around 50%), without changing the fuel consumption, and to allow a pure-electric operation with a range of 15-20 km; when the propulsion power comes only from the onboard batteries, and they are recharged from the electric mains, the operation cost per km is around a quarter the cost of corresponding fuel consumption of a vehicle without hybridization.