| The power reflux hydro-mechanical transmission system can improve the efficiency while ensuring the good starting torque ratio and stepless speed regulation compared with the hydro-mechanical power split transmission system,which would definitely have a good application prospect in engineering vehicles.This article is part of the research content of the National Natural Science Foundation of China project “Design Theory and Control Method for a power reflux hydro-mechanical transmission system”(Grant No.51375505).For the structure and parameters design methods for this power reflux hydro-mechanical transmission system,the following research works have been carried out:(1)The transmission structure of the power reflux hydro-mechanical transmission system was proposed,and the basic transmission characteristics of this system were analyzed.Based on the analysis of the cooperating between the transmission system and the engine,the structural improvement measures of the original power reflux hydro-mechanical transmission system were proposed.In addition,the constraints between the structural parameters and the operating parameters of the power reflux hydro-mechanical transmission system were analyzed,which provides a necessary reference for the parameters design for the power reflux hydro-mechanical transmission system.(2)The influence of various structural parameters on the performance of the power reflux hydro-mechanical transmission system was analyzed,and the selection basis for the structural parameters was proposed.Based on the formulating of the evaluation indexes for economy,power performance and speed regulation ability,a multi-objective optimization design method for the structural parameters of the power reflux hydro-mechanical transmission system was established.The optimized parameters of the structural parameter of the planetary gear and the ratio of the single-speed transmission were finally obtained by using the NSGA-?? multi-objective genetic algorithm.(3)Based on the reasonable matching between the power reflux hydro-mechanical transmission system and the engine,it is proposed that the negative permeability torque converter must be used in the power reflux hydro-mechanical transmission system,which provides a method for the selection of the right torque converter.Based on the one-dimensional beam theory and the maximum efficiency of the torque converter in the calculation condition,a forward design method for torque converter was established,according to the demands of the permeability coefficient,speed ratio in the calculation condition,and the starting torque ratio.This design verifies the rationality of the negative permeability torque converter in the power reflux hydro-mechanical transmission system.(4)Twelve kinds of hydro-mechanical power split transmission structures and their basic transmission characteristics were analyzed,and then the excellent transmission performance of the power reflux hydro-mechanical transmission system was verified by the analysis and comparison in torque ratio,efficiency,speed ratio width in the high efficiency area and the magnitude of change in the torque coefficient. |
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