Research On Key Technologies Of Fuel Cell Plug-in Hybrid Electric Passenger Car

With the rapid development of the automobile industry,energy shortage and exhaust emissions caused by motor vehicles have become one of the most urgent problems in the world.By contrast,the research and promotion of new energy vehicles contribute to the sustainable development of the automobile industry and guarantee people’s need for fast and convenient drive.Following the worldwide New Energy Vehicles Development Plan and China’s "Three-Vertical & Three-Horizontal" Development Strategy of New Energy Vehicles,researchers developed and researched on the plug-in hybrid electric vehicles based on existing pure electric vehicles,especially based on fuel cell plug-in Electric hybrid vehicles.These studies can on the one hand effectively improve mileage of pure electric vehicles,and on the other hand achieve absolute zero emissions.In this research,which is based on the whole vehicle development plan,studies mainly focused on vehicle power system simulation,control system integration,fuel cell system thermal management and hydrogen supply system safety control.Firstly,researchers built the whole vehicle dynamics model and fuel cell engine model for fuel cell plug-in hybrid electric vehicle.Furthermore,they put forward the parameter design method of plug-in fuel cell vehicle hybrid power system.Through analyzing the power and energy of the vehicle,researchers preliminarily determined the key parameters of the power system,and their influence on the vehicle dynamics,economical efficiency.Secondly,researchers designed the vehicle’s high & low voltage system,the control system and control strategy from the aspect of whole vehicle macro control system,and realized its actual building-up.Based on the analysis of the dynamic system of the typical fuel cell car,they proposed the corresponding electric-electric hybrid dynamic configuration,realizing the whole vehicle controlling architecture,completing the design of the high & low voltage wake-up system,and working out the finite-state stratification controlling strategy based on switch model and the motor power controlling strategy based on the prediction model.The results show that the optimization of relevant strategies can ensure stable power output of the whole vehicle,and can make prejudgment and pre-adjustment of power requirements beforehand.Meanwhile,the optimization of the power allocation for the controlling strategy guarantees energy management and further satisfies the driving needs of the vehicle.Thirdly,thermal management optimization and simulation research of the vehicle were carried out.To make full use of the waste heat of the fuel cell stack,it was associated with the power battery cooling system and the vehicle heating system.The themal of single cell in packet was analyzed.According to the temperature change of the single cell under different discharge magnification,the liquid flow pipe in the power battery pack was protocolled.Based on the change that the waste heat causes on the temperature of the single cell of power battery in different environment,and with different fuel cell stack output power,researchers tried out the optimal scheme of thermal management of power battery and fuel cell.Secondly,the waste heat of the fuel cell stack was used to heat the crew cabin to reduce the consumption of power batteries during the normal operation of the vehicle in winter.Finally,concerning the safety of the high-pressure hydrogen cylinders and other related pipelines in the hydrogen-supply system of the fuel cell vehicles when collision occurs,researchers took advantage of the analysis models and methods of LS-DYNA and Abaqus to respectively analyze the state of hydrogen cylinders and vehicle trunks in collision and the influence the collision had on the winding layer of the hydrogen cylinders.The study revealed that after the installation of hydrogen cylinder,the occupant was greatly affected when the vehicle collided.Therefore,further researches should be carried out to ensure the safety of the car occupants when the fuel cell vehicles are in collision.In addition,in order to ensure safety,and avoid hydrogen cylinder leakage and explosion in case of collision,researchers studied the influence the working pressure and the ply design have on the safety of the hydrogen cylinder in collision.The results showed that the greater the internal pressure is,the greater the peak value of the stress of the hydrogen cylinder during collision will be;Moreover,with the increase of the angle of the spiral ply,the circumferential ply load decreases while the bearing capacity of the spiral ply fiber gradually increases.The development of key technologies of fuel cell plug-in hybrid vehicle realized the trial-manufacture of its prototype.In the later actual road test,the vehicle reached maximum speed of 150km/h,0 ~ 50km/h acceleration time of 5.56 s,and 60km/h constant speed mileage of 240km(35MPa),basically meeting the pre-set technological requirements of the research and achieving the task goal of designing and developing the prototype of the functional vehicle.