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Abstract
This report describes a Milwaukee School of Engineering [MSOE] Master of Science in Engineering capstone project. This capstone project is part of an on-going investigation at MSOE’s Fluid Power Institute [FPI] involving a dynamometer assembly that simulates the trenching duty cycle of an off-highway machine—in this case, a backhoe loader. The investigation was focused on testing the hypothesis that polymer enhanced hydraulic fluids mitigate deviations in system control, thereby improving the overall efficiency of the system. MSOE FPI is engaged in several investigations to understand the tribological aspects associated with the polymer enhancement of hydraulic fluids and its effects on system performance. These investigations include dynamic duty cycle tests, step tests, and ISO 4409 testing, which is the international standard for steady state testing as defined by the International Organization of Standardization [ISO]. The investigations additionally feature ISO 8426 testing and Toet method testing – which determine the derived capacity of hydraulic fluid powered positive displacement pumps under steady-state conditions. Several hydraulic fluids, with different polymer compositions, were tested in the dynamometer assembly. The results of these tests solidified the repeatability and consistency of the test methods. Efficiency numbers from the dynamic tests were compared to the efficiency of the system in steady-state condition using ISO 4409 test methods. The results revealed that most of the system’s response was determined by activity at the pump inlet. Further investigations were then focused on the pump’s inlet. Some of the results suggested that the hydraulic fluid’s viscosity and density play a role in determining the system’s response. Moving forward, FPI plans to create and study RLC [resistance, inductance, capacitance] models of the pump’s inlet in order to understand how the fluid properties effect the system’s response.