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Traditionally, various testing methods are used to determine the lubrication properties of hydraulic fluids. The specific standard for mechanical testing of hydraulic fluids is based on a special type of hydraulic power unit, the vane pump (DIN 51 389, DIN 51 524). Numerous other procedures for mechanical testing of lubricants are used, the most important one being the gear rig test by the FZG-method (DIN 51 354), in which the tested fluid is exposed to a certain load by shearing it in a gear set. Moreover industry uses several non-standard ‘in-house’ testing methods. This situation can not be satisfying in many respects: Since only part of the interaction between fluid and component is tested with the existing test procedures, the validity of test results is limited, especially in the case of the vane pump test.

The Institute for Mechanical Engineering Design of the Technical University Hamburg-Harburg is developing a product model based tool for application engineering of hydrostatic systems, which supports the early stages of product design. To guarantee that all employees of the company have access to product data and design knowledge via Intranet the tool is WEB-based. Increased data processing support especially in the early stages of product development requires computer supported acquisition of the task, which is offered by the tool. Additionally different modules support the solution identification process by supplying design experience and giving access to realized solutions. Circuit diagram creation, selection of components, system simulation, error estimation and 3D-layout of the hydrostatic system are also supported by the tool.

Small electro-hydraulic actuators have started to replace systems with centralized hydraulic power supply in some areas. Therefore the most common systems with a variable speed electric motor in combination with a fixed-displacement pump and a constant speed motor with a variable displacement pump were compared using the load cycle of the aileron of a civil aircraft. For this load cycle the configuration with fixed displacement pump and the variable speed electric motor showed the same dynamic and a much better energetic performance than the variant with a constant speed motor and a variable displacement pump. The energy consumption could be reduced by 55 % using the motor speed as the control input. With a logic that changes the control input between motor speed and swashplate angle as a funktion of the actual motor speed the energy consumption could be reduced by another 24 %.

Traditionally, various testing methods are used to determine the lubrication properties of hydraulic fluids. The specific standard for mechanical testing of hydraulic fluids is based on a special type of hydraulic power unit, the vane pump (DIN 51 389, DIN 51 524). Numerous other procedures for mechanical testing of lubricants are used with the FZG-Test (DIN 51 354) being the most important one, in which the tested fluid is exposed to a certain load by shearing it in a gear set. Moreover industry uses several non-standard ‘in-house’ testing methods. This situation cannot be satisfying in many respects: Since only part of the interaction between fluid and component is tested with the existing test procedures, the validity of test results is limited. Reproducibility of the test results is also limited, especially in the case of the vane pump test, due to the number of necessary test procedures, cost and time expense is too high.