Research On Performance And Application Of Hydrodynamic Torque Converter With Adjustable Axial-flow Guide Vanes

With economic development, earthmoving machinery has become more and more widely applied in engineering construction. Against the backdrop of energy conservation, emission reduction and energy consumption reduction worldwide, it has become an inevitable trend to improve the performance and energy efficiency of the loader, the important equipment among earthmoving machinery. At present, majority of loaders still are equipped with the hydrodynamic transmission system for power transmission, in which the matching performance between engine and hydrodynamic torque converter is an important factor that affects the whole machine performance. Usually, the capacity characteristics of the hydrodynamic torque converter used on the loader are stationary. As the loader faces complex work conditions, the hydrodynamic torque converter cannot meet the requirements for matching performance under different work conditions, whichever way of matching is used. If a hydrodynamic torque converter with continuous variable capacity characteristics can be designed and integrated with the loader to solve the problem of matching between the engine and the torque converter, matching performance can be effectively improved, and so can the machine performance accordingly. To this end, this paper proposes to use a 7-ton loader as the research object, design a new hydrodynamic torque converter with adjustable axial-flow guide vanes and characteristics of continuity and controllability, and assess its performance and its application in the loader. The main content of research is as follows.(1) The circular circle of torque converter with adjustable axial-flow guide vanes, 370 mm in diameter, was designed by the similar design method and two circular arcs with a line. The conformal mapping method was adopted to design the blades of pump and turbine of the torque converter with adjustable axial-flow guide vanes. The blades of the stator were designed to meet the requirement of making an adjustable stator. In order to make the stator’s blades rotate, an adjusting mechanism for the guide vanes was designed and the opening range of the guide vanes was set, and the overall structure of the torque converter with adjustable axial-flow guide vanes came into shape. A numerical simulation calculation by the CFD technology was carried out on the torque converter with adjustable axial-flow guide vanes, to analyze its internal flow field distribution and that of the adjustable stator. The primary characteristics of the torque converter with adjustable axial-flow guide vanes were revealed, and its performances in situations with varying openings of the guide vanes were studied as priority.(2) Based on the parameters of a 7-ton loader’s power transmission system and the whole machine, a mathematical model of the engine and the hydrodynamic torque converter with adjustable axial-flow guide vanes was set up. The common work input characteristics and output characteristics and the change range of working point under driving and operating conditions were analyzed, and compared with those of the original machine. According to the common work matching characteristics, traction, max speed, acceleration time, grade ability and amount of fuel consumed per hundred kilometers of the loader under the operating condition were calculated and compared with those of the original machine. Research shows that the hydrodynamic torque converter with adjustable axial-flow guide vanes can significantly improve the machine performance of the loader under driving conditions.(3) Test was made on a 7-ton loader carrying out the V-shaped digging and loading in an operation cycle. Results of the changes of the engine throttle, speed and deduction in engine power within an operation cycle were acquired, based on which a dynamic simulation model of the original hydrodynamic torque converter was established by MATLAB/Simulink. In order to access the dynamic changes in machine performance of the whole loader equipped with the hydrodynamic torque converter with adjustable axial-flow guide vanes, based on the best matching principle, the strategy of controlling the opening of the guide vanes was adopted, and the a dynamic simulation model of the hydrodynamic torque converter with adjustable axial-flow guide vanes was established by MATLAB/Simulink as well. And these simulation results are compared with those of the original hydrodynamic torque converter. By comparison analysis, it was learned that the machine performance of the loader was improved when installed with the converter with adjustable axial-flow guide vanes.