Achievement of Fuel Savings in Wheel Loader by Applying Hydrodynamic Mechanical Power Split Transmissions

Abstract: The fuel economy of wheel loaders is deeply affected by the efficiency of their propelling transmissions, however, the torque converter (TC) in existing propelling transmissions is a low-efficiency component and leads to excessive energy consumption. Accordingly, this paper replaces the TC with a hydrodynamic mechanical power split transmission (HMPST) for improving the fuel economy of wheel loader. Based on probability similarity theory, the typical operating mode for the vehicles is constructed, which is used to evaluate the energy consumption performance of the selected solutions. The four reasonable solutions, which can be initially applied to wheel loaders, are selected from among the HMPSTs using the lever diagram. Furthermore, the comparisons on efficiency and loading characteristics between these four solutions and a prototype TC are conducted. The design optimization for all the four solutions is implemented, in order to find the optimal fuel saving solution relative to the prototype TC, and only one solution with pure power split can meet the constraints. Finally, a simulation model of the wheel loader powertrain is established for validating the effectiveness of this optimal solution. The results show that the optimized solution can effectively improve the fuel economy of wheel loaders compared to the prototype TC and provides a novel substitute for current technology.