Study on LPG-Electric Hybrid Bicycle

A LPG (Liquefied Petroleum Gas) - electric hybrid bicycle is designed in this paper. In accordance with the different traffic conditions, the hybrid system, which contains a hub motor and a LPG engine, can work at engine-mode, battery-mode, and hybrid-mode, separately or in cooperation. The switching of these modes is electrically controlled. Thus the internal combustion engine can work in high efficiency and the bicycle has better dynamic and economic performance. It is worth to mention that, when LPG is used as the fuel, the system´s emission performance will be reduced considerably. At the same time, the noise performance will be further improved too. The storage battery works only at the stage of start and at the low-speed condition. Once the speed of bicycle is up, the LPG engine starts automatically and charges up the battery, which will prolong both the service life of the battery and the maximal travel mileage. As a result, the requirements of the battery´s capacity and weight can be significantly reduced.