Analysis on the shift strategy of hydro-mechanical infinitely variable transmission based on the orthogonal test

Abstract

This article focuses on the shift strategy of hydro-mechanical infinitely variable transmission. A computer simulation is carried out to investigate the shift strategy, and the simulation results are verified by the test data. There are four typical working conditions in the continuous shift process, among which the shift process from F2(N) to F3(P) plays a decisive role in shift quality. The shift strategy based on the physical parameters from F2(N) to F3(P) is lower engine rotating speed, smaller load torque, lower main circuit pressure, and larger speed valve flow rate. The shift strategy based on the shift time from F2(N) to F3(P) is to switch the third group of clutches first, then disengage the first group of clutches, and engage the second group of clutches at last. The results show that the shift quality of hydro-mechanical infinitely variable transmission can be improved greatly by the optimization of physical parameters and shift time.