The importance of pump/motor efficiencies for mobile machines operating costs

Unavoidably rising fuel costs and planned pollution legislations like Tier 4/Eu IIIB are increasing the focus on efficiency and power losses in the mobile machinery market strongly, especially for hydrostatic pumps and motors as key components for drivelines. This paper discusses the importance of pump/motor design on the driveline efficiency and operating costs of mobile machines. Reliable and precise loss models of hydrostatic units are essential for this investigation, driving requirements for special attention to efficiency measurement and modeling. The energy saving potential, and the reduced needed cooling power combined with additional losses, results in lowering direct operating costs in the range of thousands of $ per year.