Optimal Efficiency Shift Schedule of Automatic Transmission for Construction Vehicle

The working conditions for construction vehicles (wheel loader, bulldozer, etc.) are very complicated and the operating loads change frequently and sharply. This result will lead to lower powertrain efficiency. In order to maintain the high efficiency of construction vehicles equipped with automatic transmission, an optimal efficiency shift (OES) schedule with 3-parameter (vehicle speed, throttle opening, and hydraulic pump pressure) is proposed and designed by creating and analyzing the powertrain model. A dynamic simulation model using the OES schedule for the construction vehicle has been established by MATLAB/Simulink. The simulation results show that the 3-parameter shift (3PS) schedule is superior to the 2-parameter (vehicle speed and throttle opening) shift (2PS) schedule in energy saving.