Energy-Efficiency Comparison of Different Implement Power-Train Concepts to Each Other and Between Different Heavy-Duty Mobile Machines

Abstract—For the electrification of heavy-duty mobile machines (HDMMs), alternative power-train concepts that are more efficient than conventional valve-controlled systems can be an important key that extends the operation time by making better use of the limited amount of available battery energy. Since power-train concepts are universal and can be applied to various types of HDMMs with different application conditions, it is advisable to assess and compare concepts on multiple of those machines and on the basis of a standardized investigation method. For this purpose, simulations of a telehandler, a wheel loader, and an excavator are done in this study. Each HDMM type is simulated with different setups that each apply one of three concepts: pure conventional valve-control in a load sensing (LS) system, as the benchmark, or one of two alternative concepts that were previously presented by the authors. The two alternative concepts are namely an LS system with the option to replace the metering valves of single actuators with a hydraulic motor connected to an electric generator and secondly a system with an electric machine that drives an LS pump as well as displacementcontrolled actuators. The simulations show that both alternative concepts perform equally well on the reference telehandler and the wheel loader with maximum primary energy savings in a work cycle mix of around 37% on both machines compared to the reference setups. For the excavator, on the other hand, the displacement-controlled concept performed even better and reached savings of up to 48%.