Research On Variable Speed And Control Of Multi-Hydrodynamic Element For Rail Vehicle

As one of the most common transport machinery in railway engineering,engineering and telecommunications departments,railway engineering vehicle is a typical tool for transporting personnel,equipment and handling emergencies.It plays an increasingly important role in railway construction and maintenance.The main transmission modes of railway engineering vehicle are electric transmission,mechanical transmission and hydrodynamic transmission.The structure of electric transmission vehicle is complex,the manufacturing cost is high,the mechanical transmission components are many,the faults are many,and the maintenance workload is large,which can not meet the needs of high-power railway vehicle.The hydrodynamic transmission has stepless speed change,simple operation,stable start-up,low manufacturing and application cost.Multi-hydrodynamic element transmission is the most common and advanced transmission mode of railway engineering vehicle at present.Its main hydrodynamic components,such as hydrodynamic torque converter,hydrodynamic coupling,and matching between them,have a very important influence on the performance of Railway Engineering vehicle.The control strategy of automatic switching between hydrodynamic components plays an important role in realizing automatic transmission of Railway Engineering vehicle.At present,I cross the track engineering vehicle multi-hydrodynamic element transmission device mainly depends on imports from Germany.Based on this,a transmission system with multi-hydrodynamic elements is designed for railway engineering vehicle.The characteristics of each hydrodynamic element of railway engineering vehicle and its matching with power machine are studied.The control system for automatic transmission of railway engineering vehicle by automatic switching of hydrodynamic elements is studied.The main research contents and conclusions are as follows.（1）The overall structure of multi-hydrodynamic components transmission device of track engineering vehicle is designed.The multi-hydrodynamic transmission device of track engineering vehicle is composed of a hydrodynamic torque converter,two hydrodynamic couplings and a hydrodynamic retarder.It has the advantages of high transmission efficiency,wide speed range and large power transmission.According to the similarity method,the hydrodynamic components are designed.The effective diameter of the circulation circle of the torque converter is D=380mm,the effective diameter of the hydrodynamic coupling is D=360mm,and the effective diameter of the hydrodynamic retarder is D=438mm.The design of the three-dimensional model of each hydrodynamic element is completed,the hexahedron mesh is divided,and then the calculation model is simulated.The characteristic curves of each hydrodynamic element are obtained,which lays a foundation for the matching of the power machine and the hydrodynamic element in the later research.（2）The hydrodynamic transmission system of railway engineering vehicle and its matching with power locomotive and vehicle are analyzed.The hydrodynamic torque converter in the hydrodynamic transmission system is used to provide large traction force when the vehicle starts,and the hydrodynamic coupling is used for high-speed operation of the vehicle.It has high transmission efficiency when the vehicle runs at high speed and high working conditions.The hydrodynamic retarder is used for braking of the vehicle.The matching of power machine with hydrodynamic torque converter and hydrodynamic coupling is studied,its mathematical model is established,and the traction characteristics of the transmission system of track engineering vehicle are calculated and analyzed.Finally,the maximum traction force F_max=68kN is obtained,and the maximum driving speed is v_max=114 km/h,which meets the design requirements.（3）The control method of the transmission device of the multi-hydrodynamic element of the track engineering vehicle is studied.Firstly,the working principle of the multi-hydrodynamic transmission system of railway engineering vehicle is analyzed.Based on the speed recognition and feedback of the vehicle speed signal,the system automatically judges and switches the working hydrodynamic components and achieves automatic transmission.The control system adopts PID control,and the PID controller is designed.According to the principle of system control,a set of hydrodynamic control system is designed to realize automatic switching of hydrodynamic components and automatic transmission of the system.Based on AMESim,the simulation models of system oil filling module,oil discharging module and vehicle simulation are established,and the dynamic oil filling and discharging process of each hydrodynamic component is analyzed.