Simulation And Control Technologies On Powertrain System Of A Hydraulic Hybrid Vehicle

With the problems of energy consumption and environment protection have become increasingly important,it provides a forceful impetus for developing energy-saving and environment-friendly vehicles.Hybrid hydraulic vehicles have the advantages of hybrid vehicles and high braking energy recovery efficiency,and are one of the development directions of energy-saving and environment-friendly vehicles.In this paper,the system simulation and control technology research is carried out for a novel hydraulic hybrid vehicle with four independent wheel motors,including the following aspects:(1)A novel hydraulic hybrid vehicle with four independent wheel motors is designed.The structure and advantages of the vehicle are analyzed.The working process of the vehicle in the driving and braking modes is planned in detail according to the design scheme.The power system simulation test bench is developed,and the parameters matching and selection are carried out.The electronic control unit hardware and software are developed based on the DSP controller,which establish a platform for the semi-physical simulation test.(2)The hydraulic hybrid vehicle with four independent wheel motors simulation model is built.A forward simulation block diagram is designed and a 1/4 vehicle simulation model was built based on AMESim.The tests of the charging and discharging process of the hydraulic accumulator are carried out on the test bench,and the simulation model is calibrated,which guarantees the accuracy of the vehicle simulation model.(3)The parametric simulation analysis of vehicle power performance is carried out based on the simulation model.The simulation results show that 0-100km/h accelerating time is 15.7s,and the maximum speed of the vehicle is 120km/h,and the maximum grade ability is 29%.The driving range is 753 m under the pure hydraulic drive conditions at the constant speed of 30km/h.The influence law of each working parameter on the working process is analyzed,and lays a foundation for the research of control strategies.(4)The vehicle energy management strategies are studied based on the simulation model.The controllers of rule-based,fuzzy logic control,global optimization and optimization rules are designed respectively.The simulation and comparison are carried out under the UDDS driving conditions.The simulation results show that the fuel economy is the best based on the global optimal energy management strategy,equivalent to a fuel consumption of 12.4L per 100 kilometers,and fuel economy is 31.1% higher than that of the prototype.The optimized engine operation and effective braking energy recovery result in the fuel economy improvement.