Research of Speed Ratio Matching Strategies of Hydro-Mechanical Continuously Variable Transmission System for Tractor

Abstract

To realize the optimal power and best fuel economy performance of engine, the speed ratio matching strategies of tractor with hydro-mechanical continuously variable transmission (HMCVT) system are studied. The engine output torque model and fuel consumption model are established based on engine test results. On the basis of the engine rotary speed feature, the target speed ratios of HMCVT system in the numerical table are given, which realizes the optimal power and best fuel economy performance mode within the speed ratio range of the HMCVT system. The tractive performance of the tractor equipped with HMCVT and original tractor are compared. The results show that the tractors assembled with HMCVT can gain a continuously variable speed. Additionally, in any traction force, the engine works near full load. As a result, the tractors with HMCVT can improve themselves productivity and fuel economy.