Research On The Energy Saving Control Strategy Of Parallel Hybrid Loader

Loaders are large-scale transport vehicles which are necessary for engineering construction and have made an important contribution to national economy. But there are also some defects such as high fuel consumption and poor emission because of its harsh working environment. The defects greatly contradict to the current shortage of oil resources and increasing environmental awareness. It is imperative that do research on energy saving and emission reduction technology of loaders. The main reason of high fuel consumption and poor emission is that the engine works for long hours in the low efficient field. Therefore, increasing the work efficiency of the engine has become the key to solving the problem. This paper adopts the parallel hybrid structure, introduces the instantaneous optimization control strategy of engine working point and the dynamic balance optimal control strategy of SOC concerning that the dynamic balance of SOC strongly influences the distribution of engine work points which influences the efficiency of engine and tests the validity of control strategies using simulation and experiments. The main contents include:(1) Research on Hybrid loader structure. Analyzed the structure of a conventional loader and adopted the parallel hybrid structure after a comparison of three hybrid schemes basing on the working environment of loaders. Did parameter matching for the parallel hybrid loader basing on the working mode and data.(2) Modeling for the parallel hybrid system. Built engine, generator, motor, super capacitor, hydraulic system, forward and reverse models of torque-converter which were put forward for the first time, and working resistance models. Basing on the former models, established the whole vehicle SIMULINK model.(3) Research on the instantaneous optimization control strategy of engine working point. Firstly, introduced the instantaneous optimization control strategy of engine working point. Secondly, optimized the increment of motor torque using fuzzy logic when the SOC>0.8 and SOC<0.4. Last, tested the control strategies by SIMULINK model.(4) Research on the dynamic balance optimal control strategy of SOC. Firstly, introduced the dynamic balance optimal control strategy of SOC. Secondly, optimized a parameter and the membership functions of the fuzzy logic used in the former SOC control strategy basing on immune genetic algorithm. Last, tested the control strategies by SIMULINK model.(5) Control strategies experiments. Built the parallel hybrid loader bench and did the experiments of all control strategies.After the simulations and experiments, it was found that the instantaneous optimization control strategy of engine working point and the dynamic balance optimal control strategy of SOC were effective to enhance the efficiency of engine and reduce the fuel consumption.