Modeling And Analysis Of Hydro-Mechanical Variable Transmission Based On Simulink/Simscape

Hydro-mechanical variable transmission (HMT) is a new kind of transmission devicewhich combines stepless speed adjusting gear of hydraulic transmission and higheffectiveness of mechanical transmission perfectly. Its performance has a very tremendousinfluence on the performance of the entire vehicle and the transmission system life. HMTinvolves mechanical transmission, hydraulic transmission and frictional transmission. Thedynamic model is complex with intensive non-linear unit. Building complete dynamicmodel and carrying out analysis lay a solid foundation for the further-study of HMT.This article takes two-ranges HMT as the research object, its dynamic simulinkmodel were established, the dynamic analyses of adjusting the speed of each range andshifting process are also carried out. The main contents can be summarized as follows:Based on studying the structure, principle and working process of HMT, steplessspeed characteristics and the factors which produce the impact in the shift process wereanalyzed, meanwhile, torque variation and power flow during shift process were alsoanalyzed. The shift process has been divided into five stages in the theory: the hydraulicstage, the hydraulic torque phase, inertia phase, hydro-mechanical torque phase, andhydro-mechanical stage. The phenomenon of torque reverse, hydraulic high and lowpressure current exchange, and power recirculation of the constant hydraulic componentswere analyzed. In Simulink/Simscape, the simulation model of HMT was built, includingHMT model, engine model, and vehicle model. With well simulation and analysis, themethod to improve the quality of shifting was put forward.