Power Train System Control of Electric Loader Based on Positive Flow System

Energy conservation and emission reduction have drawn more and more attention in the world. Loaders are widely used in various earthworks. However, traditional loaders with high energy consumption and poor emission cannot meet the needs of sustainable development. Electric loaders can achieve zero emission by replacing the engine with the electric motor, which is considered to be one of the main trends in future development. However, the existing electric loader only uses the electric motor to simulate the operation of the engine without fully considering the characteristics of the hydraulic system, resulting in the inability to optimize the energy efficiency and control performance of the system. In this paper, an electric motor with excellent speed regulation was employed. A positive flow system based on variable speed for constant displacement pump was studied. The efficiency of the power train system was analyzed. The relationships of the opening area of the main valve core, the system demand flow, and the pilot pressure were studied. A variable speed control strategy based on the pilot pressure control was put forward. In order to verify the feasibility of the proposed system and control strategy, simulation and experiments were carried out. The results showed that the proposed system has better energy saving and maneuverability than the traditional constant flow system.