The performance and efficiency of hydraulic pumps and motors.

University of Minnesota M.S. thesis. January 2010. Major: Mechanical Engineering. Advisors: Thomas Chase, Perry Li. 1 computer file (PDF); xii, 123 pages, appendices A-C. Ill. (some col.)This research consists of predicting the performance and efficiency of hydraulic pumps and motors, both with experiments and modeling. A pump and motor test stand is constructed to measure the efficiency of an axial piston swashplate pump/motor unit. A regenerative loop hydraulic system is used to reduce the power requirements of the test stand. The test stand uses an xPC Target data acquisition system. Test conditions focused on low displacement and low speed regimes. Efficiency values ranged from less than 0% to 82%. An existing efficiency model in the literature is fit to the data. Several improvements to the model are suggested. The correlation was satisfactory, but room for improvement still exists. Displacement sensors are recommended in the pump/motor units being tested. This is to avoid the significant uncertainty associated with calculating the derived volume based on the data