Modeling And Simulation Analysis Of Hydro-mechanical Continuously Variable Transmission Power Shift Process

Hydro-mechanical continuously variable transmission is a kind of double power flowtransmission system constituted by infinitely variable hydraulic power flow and highefficient mechanical power flow in parallel, which is an ideal transmission system ofheavy vehicle. Speed fluctuation of the fixed displacement hydraulic component in powershift process of hydro-mechanical continuously variable transmission produces shiftimpact and reduces the ride comfortableness. Find out the factors affect shift quality, putforward a scheme which can minimize shift impact and improve shift quality is the key todevelop the hydro-mechanical continuously variable transmission.Put the arithmetic two-range hydro-mechanical continuously variable transmission asthe research object in this paper. Modeling and simulation analysis of hydro-mechanicalcontinuously variable transmission power shift process was carried out. The main researchconstant is as flowers.(1) Analyzed its characters of rotational speed, speed ratio, outputtorque and power.(2) A hierarchical and modular modeling idea was adopted, establishedvarious subsystems of hydro-mechanical continuously variable transmission dynamicequations and simulation models in MATLAB/Simulink/Stateflow software platform.According to topology structure and causal relationship connect every sub model, formeda complete hydro-mechanical continuously variable transmission simulation model. Thecorrectness of the simulation model is verified through the contrast analysis of test andsimulation.(3) Studied the influence law in hydro-mechanical continuously variabletransmission power shift process of oil drain and charge sequence, brake pressure, oildrain and charge times and load. Simulation analyzed the vehicle driving process, whichequipped with hydro-mechanical continuously variable transmission. The simulationresults show that hydro-mechanical continuously variable transmission simulation modelcan reflect speed ratio changing in range and power shift dynamic process accurately.