Study On The Shift Schedule For Hybrid Electric Bus

Hybrid technology is regarded as one of the most promising technologies for clean vehicles through world wide because of its economization and decontamination. Since this century, China has also put a lot of efforts to rapid the commercialization process of hybrid electric vehicles, for the sake of saving energies and decreasing pollutions. But as you know, the crucial section of hybrid technology is the control strategy, so under this circumstance this paper investigated the shift schedule in the steady coordinate control strategy of the hybrid electric bus roundly.The paper advances the feasible shift schedule for hybrid electric buses based on their different styles and presents the solving method in detail. And a computer simulation study for analyzing the shift schedule is offered.First, the paper studies the concept, sort and development instance of the shift schedule for the conventional vehicles. Then the solving methods of optimal-power shift schedule which based on two-parameter-controlled of vehicle speed and engine accelerator pedal position, and optimal-fuel economy shift schedule which based on two-parameter-controlled of vehicle speed and engine torque for conventional vehicles are presented.Second, the paper studies the power shift schedule for hybrid electric buses. A two-parameter-controlled power shift schedule and its solving method are brought forward. And then, a three-parameter-controlled power shift schedule for mild hybrid electric buses with ISG and its solving method are presented in detail. The parameters of the shift schedule are vehicle speed, throttle position and the state of charge. Furthermore, a computer simulation study for analyzing this shift schedule is carried out, and the results of the simulation shows it can enhance the accelerate performance of the buses comparing with the two-parameter shift schedule inherited from conventional vehicles. Third, the paper introduces the fuel-economy shift schedule for hybrid electric buses. A three-parameter-controlled economical shift schedule for hybrid electric buses and its solving method are presented. The parameters of the shift schedule upward are engine torque, motor torque and vehicle speed. Shift schedules upward in electric assist mode, generation mode, engine only mode, motor only mode and their solving methods are discussed. Shift schedule downward is also three-parameter-controlled. The three parameters of shift schedule downward in brake mode are motor brake torque, mechanic brake torque and vehicle speed. The principle to solve shift schedule downward in brake mode is to regenerate as much as possible without degrading the braking ability at the same time. The shift schedule for hybrid electric buses is a further step of the automatic shift theory for hybrid electric vehicle. Compared with the two-parameter-controlled shift schedule inherited from conventional vehicles, it can save fuel consumption in driving mode and increase the regeneration efficiency remarkably in braking mode.Finally, the paper makes a comprehensive analysis on a variety of driving environment and driver's intention for HEB, studies the typical driver manipulation features, divides driver's intentions into five interrelated style and proposes the identification method which integrated the driving environment and the operation of the driver. On this basis, in accordance with the corresponding real vehicle and driver experience, the paper develops shift strategies under different driver intention. And the paper uses AVL/Cruise to establish the physical model of HEB, including the engine, motor, battery, transmission, wheels, body, and other major assembly, and uses Matlab/Simulink to establish vehicle control model, which mainly improves the Transmission Control Strategy Shift Control Module. Using the integrated platform of AVL/Cruise and Matlab/Simulink to simulate the operation of CA6110HEV under different shift strategy in a number of traffic circulation condition, through the simulation results contrast, certificates the shift strategy based on the driver's intention identification, which enables CA6110HEV to implement the intention of driver, and vehicle access to better fuel economy.