Energy-Efficiency Comparison of DifferentImplement Powertrain Concepts to EachOther and Between Different Heavy-DutyMobile Machines

For the electrification of heavy-duty mobile machines (HDMMs), alterna-tive power-train concepts that are more efficient than conventional valve-controlled systems can be an important key that extends the operation timeby making better use of the limited amount of available battery energy.Since power-train concepts are universal and can be applied to various typesof HDMMs with different application conditions, it is advisable to assessand compare concepts on multiple of those machines and on the basisof a standardized investigation method. For this purpose, simulations of atelehandler, a wheel loader, and an excavator are done in this study. EachHDMM type is simulated with different setups that each apply one of threeconcepts: 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 LSsystem with the option to replace the metering valves of single actuators witha hydraulic motor connected to an electric generator and secondly a systemwith an electric machine that drives an LS pump as well as displacement-controlled actuators. The simulations show that both alternative conceptsperform equally well on the reference telehandler and the wheel loader withmaximum primary energy savings in a work cycle mix of around 37% onboth machines compared to the reference setups. For the excavator, on theother hand, the displacement-controlled concept performed even better andreached savings of up to 48%.