Research On Design And Simulation Of Hydraulic Hybrid System In Wheel Loader

Because of the problem of energy crisis and environmental pollution being more worse and worse with the rapid development of economy, green economy, which focus on energy-saving and consumption-reducing, has been a theme of social development. Loader is a main kind of construction machinery, which has the weakness of high fuel consumption, bad emission and low efficiency of the whole machine because of its complex working environment, the research on energy-saving and consumption-reducing gradually become the focus of public attention.In recent years, the application of hybrid technology in the automotive field is successful, which provides a reference for the energy-saving study of loader. Hydraulic hybrid, as a representative of hybrid technology, has many advantages such as high power density and high energy efficiency and so on. It is especially suitable for loader, which has features such as frequent load-changing and start-stop.In view of the above problems, adopting the research methods of theoretical analysis, calculation and simulation, and taking a ZL50 loader as the test object, this paper carried out some research for the hydraulic hybrid system of loader. The main contents include: analyzed the typical working condition of loader, energy consumption during the work and the research feasibility of hydraulic hybrid system, and compared with different hybrid system forms. Then the design of parallel hydraulic hybrid structure of loader based on the traditional loader, was determined, which is much more suitable for loader. Combining with the components properties of system and matching theory, the parameters of main component were matched. The control strategy of engine working point aimed to improve the system dynamic performance and fuel economy was put forward after analyzing loader’s working characteristics and hydraulic hybrid system’s operating mode. According to the working principle of main components in the hydraulic hybrid system, the engine, hydraulic pump/motor, hydraulic accumulator model and load model were established. Finally, the power performance and fuel consumption under typical operating mode of loader were simulated in MATLAB/Simulink.From the simulation analysis results, it is shown that the engine working points of parallel hydraulic hybrid loader can stable in high efficient area compared with conventional loaders. And the hydraulic pump/motor can accomplish the goal of peak load shifting to dramatic changes of load torque. What’s more, the hydraulic hybrid loader can reduce the installing power of engine, and a good energy-saving effect that the fuel efficiency increases by 8.23% is achieved. The research in this paper provides a relevant theoretical basis for the research on hydraulic hybrid technology of other construction machinery.