This paper presents a new design concept of transmissions for the hybrid scooters. These transmissions consist of a one-degree-of-freedom planetary gear train and a two degree of freedom planetary gear train to from a split power system and to combine the power of two power sources, a gasoline engine and an electric motor. In order to maximize the performance and reduce emissions, the transmissions can provide a hybrid scooter to run five operating modes. They are electric motor mode, engine mode, engine/charging mode, power mode and regenerative braking mode. The main advantages of the transmissions proposed in this paper include the use of only one electric motor/generator, need not use clutch/brake for the shift of the operating modes, and high efficiency. The kinematics and mechanical efficiency analyzes are performed and according to these results, the evaluation of transmission power performances are accomplished.
Scooters are the most widely used vehicle. it is more stable , simple design and cheap. Because of its extensive use many measures are taken by the government to reduce its pollution. Many motor cycle manufacturers developed battery/fuel cell powered electric scooters but they have not yet successfully captured significant market share because of the poor performance of batteries together with the lack of recharge stations. Although using fuel cells in automobiles could significantly reduce emissions to almost zero, its application for scooters is limited by cost and weight. It is obvious that the fuel-cell powered scooters are not likely to displace gasoline scooters in the near future. Hybrid electric vehicles are being developed in an attempt to overcome the limited range problems of battery powered electric vehicles, while significantly reducing the emissions.
The hybrid scooter system utilizes a gasoline engine and an electric motor to provide the traction force to the rear wheel. The electric motor can function as a motor or a generator, according to the driving condition and battery power levels. The electronic controller receives commands from a driver and receives feedback signals from sensors to select the operating mode and to decide how much power is needed to drive the scooter and how much to charge the battery. One of the strategies applied in this hybrid system is to run the electric motor only for the lower speeds so that the emission in urban areas is limited to the minimum. For the maximum performance and climbing hills, both the electric motor and the engine drive the scooter simultaneously. On cruising, the engine drives the scooter and simultaneously charges the batteries by switching the electric motor into a generator. The engine will be controlled to operate at the optimal specific fuel consumption regions where the emissions are also lower.