Traditionally, various testing methods are used to determine the lubrication properties of hydraulic fluids. The standard for mechanical testing of hydraulic fluids is based on the Vickers V-104 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 particular 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 and the validity of test results is limited, especially in the case of the vane pump test. When run under the same conditions, some tests are lead widely varying with the problem of reproducibility. Due to the number of necessary test procedures, cost and time expended is too high. Finally, there is no proof that commonly used procedures will be suitable for more modern fluids such as biodegradable fluids.
This paper describes the development of a new application-related test procedure for Mechanical Testing of Hydraulic Fluids, performed by the authors to overcome the problems discussed above.