| Energy saving, environmental Protection and Safety remain the three subjects in today's world. With the development of modern technology, automobiles are becoming one of the main traffic tools for peoples, but they also consume a large of oils. With the development and progress of the society, the yield and possession quantity of the conventional internal combustion engine (mainly be gasoline-fueled and diesel-fueled) is on the rise, which entraps the environment pollution and energy shortage into a vicious circle. On the one hand, motor vehicle exhaust becomes the main source of air pollution of global environment; on the other hand, motor vehicles consume large numbers of oil and gas resource. If human further adopt internal combustion engine (ICE) technique to develop automotive industry, energy security and environmental protection will assume huge pressure. How to improve the performance of the automobile and reduce energy consumption and the amount of pollution is the important content of the automotive technique research at present. Therefore, many countries are now researching and developing electric vehicle (EV) in order to reduce energy consumption and the amount of pollution.Comparison with conventional ICE, EV has the advantage of zero emission, but the power performance of the EV is worse, the range is shorter, and the production cost of battery is high.Compared with EV, the significant advantage of fuel cell electric vehicle (FCEV) is that FCEV has the same range with ICE, but the cost of fuel cell is very high, it is even much higher than the battery of EV.Hybrid electric vehicle (HEV) applies the combination of engine and battery, which can increase the range of EV and achieve higher vehicle speed. It also can improve fuel economy of conventional ICE and reduce the amount of pollution to a certain extent. In addition, the production cost of HEV is lower than EV and FCEV, so it is hopeful that HEV will be well developed in current times. HEV has more components than conventional vehicle, so it increases weight and volume. But it has less influence on big transit bus than on car. So many experts think the hybrid electric bus (HEB) will realize its industrialization firstly.This paper studied the traditional bus LCK6112RG running in the urban traffic system, and refit it to be LCK6112RGHEV On basis of meeting the dynamic performance required by city drive cycle, the design object was to improve the fuel economy and decrease the emissions. Enclosing this target, it firstly analyzed and compared the drive structure and type of HEV, and determined the layout pattern of LCK6112RGHEV drive system. According the real urban drive cycle and national standard about the dynamic performance of HEB, it formulated the performance index of LCK6112RGHEV and accomplished the parts selection and parameters matching of drive system. Then, it modeled the parts in ADVISOR according to the parameters, made simulation for the designed complete vehicle in Chinese typical drive cycle and compared it with conventional bus, it verified that the parameter selecting was reasonable and hybrid power was superior.Finally, it made analytic comparison for "thermostat" and "power follower" control strategy of SHEB, analyzed the reason that why the effect of fuel-saving was not obvious and made improvements and analysis for two control strategies. It was proved that the effect of fuel-saving was relatively ideal and provided theoretical guidelines for the optimization design of HEB.
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