Study On Matching And Optimization Of The Electrical City Bus Powertrain

With the increasing of the amount of cars, more and more traffic jams occur in the city and environmental pollution has been gradually serious. One of the ways to release the traffic jam and environmental pollution is to develop the urban electric-bus system. At present, In terms of the research and application of electric-buses, there are three factors which limit its development, including the short mileage, high cost and the constraint of charging time. In this paper, in order to have a further study on the electric-bus, a ranger extender is applied on electric-buses to extend the mileage. Meanwhile, it is supposed to find a feasible scheme to extend the mileage of buses.Combined with the operational principle of hybrid vehicles, the concept of high degree mixing is applied, which helps us define the structure and feature of electric-buses. Furthermore, power train system and design requirement of range-extended electric vehicles are confirmed in this paper. Based on this research, the key components of the electric-buses can be selected, and the parameters of the components can be determined.This paper illustrates the operating principles of the ADVISOR, which is an electrical vehicle simulation software. ADVISOR software system is redeveloped for the original model and interface. Range-extended electric-bus model is added in order to achieve the simulation contrast analysis of multiple-schemes.Furthermore, a new model of the range-extended electric-bus is built based on the model. Following the principle that performance will not be changed to meet the demand of pure-drive electric-buses by verifying key components of power system, the requirement of operation features for some key components is proposed in this paper. In the range-extended mode, in order to extend the bus mileage, many factors which will influence the vehicle mileage is analyzed, like rolling resistance coefficient of the bus, the battery capacity, opening time of rang extender and the brake energy recovery. Afterwards, a feasible scheme of extending the mileage of pure-drive electric- bus was proposed in this paper and it provides the theoretical basis for the prototype development and real vehicle test.Finally,in order to find the best scheme quickly and effectively,ADVISOR software and the genetic algorithm are combined together. It is aimed to achieve longer mileage and low cost. With the genetic algorithm, four variables like the battery capacity, charging power, motor torque and motor speed can be regulated automatically. In this way the range-extended electric-buses can be optimized.