Research On The Economy Of Hybrid Electric City Bus Based On EMT

New energy vehicles can improve the fuel economy of the vehicle,reduce pollutant emissions.And the hybrid electric vehicles have the advantages of traditional vehicles and pure electric vehicles,combined with the current technical conditions,so it has a certain positive significance to develop hybrid vehicles at this stage.By analyzing the working characteristics of hybrid vehicles city bus,combined with the characteristics of EMT system,a single axis parallel scheme based on EMT system is established.Under the premise of meeting the vehicle performance,this paper combined with the power demand of the city bus driving cycle in our country,and taking into account the power requirements of the vehicle accessories,completed the selection of two kinds of power system.The matching content mainly includes the engine,EMT system and power battery.Finally this paper analyzes the vehicle quality and cost of the two kinds of schemes.For the hybrid electric city bus with EMT system,it can control the output of the engine and motor torque,According to the structural characteristics of the power system,the energy management control strategy is developed,so that the torque output characteristics are the best.Based on the logic threshold,the distribution control strategy of torque is completed according to the SOC state.By analyzing the characteristics of EMT system,this paper established the shift schedule based on the throttle opening and the speed of the vehicle,and on the basis of that a comprehensive shift control strategy is developed.The changes of the passenger carrying capacity of the city bus are larger,and the quality of the whole vehicle will affect the shift speed,so the shift speed should be modified according to the change of the quality of the vehicle.The vehicle road conditions and driver's intentions will have an impact on the shift strategy,this paper introduces the fuzzy control to modify the basic shift strategy.A whole vehicle model was established based on Cruise software.The shift control module,energy management module and other control modules are established in Matlab/Simulink.This paper uses API module to realize the combination of the two simulations.According to the analysis of the simulation results,two kinds of power system could meet the requirements of the vehicle dynamic performance.According to the analysis of Chinese city cycle,it can be known that the power system scheme of small power engine and high power motor is adopted,and the fuel consumption is reduced by 14% compared with the high power engine and small power motor.The plan increases the chance of working in the low fuel consumption area,and the motor can work independently in most cases,thus it reduces the consumption of energy and improves the economy.