Orel O. Improving the operational efficiency of construction and road-building machines by ensuring useful lifetime of hydraulic drive pressure fluid

The thesis deals with improving operational efficiency by ensuring timely replacement of hydraulic drive pressure fluid in construction and road-building machinery. The thesis contains analyses of influence of pressure fluid contamination on the condition of the hydraulic equipment elements of construction and road-building machinery and on their operational efficiency, as well as proposition to use wear-preventive property coefficient to determine the lifetime of pressure fluids. An equation of dependence of wear rate of hydraulic elements on Kj coefficient was obtained, laboratory studies were conducted and correlation between Kj, coefficient value and wear-preventive properties of I-G-A-32 and MG-46-B pressure fluid samples with ChKM and SMC-2 friction and wear machines was determined. Performance tests of GR165 motor grader showed that the lifetime of Hydro HV 46 pressure fluid with wear-preventive property coefficient is about 1200 machine-hour.