Comparative study of HM and HV VG 68 oils under press-like pressure - temperature conditions

Hydraulic systems, such as hydraulic presses, operate under demanding industrial conditions, where variations in pressure, flow rate, and temperature significantly affect the physical properties of hydraulic fluids - particularly viscosity and density. This study investigates the influence of these parameters on the behavior of two mineral hydraulic oils, ISO HM VG 68 and ISO HV VG 68, and evaluates their role in maintaining system efficiency and reliability. The research is conducted through five integrated phases, including real-time experimental testing on an operational press, fluid property analysis before and after filtration, simulation under multiple pressure regimes (80-120 bar), and mathematical modeling of internal leakage to estimate volumetric efficiency. Results show that HV oils retain viscosity more effectively under thermal stress, reducing internal leakage and maintaining higher volumetric efficiency - up to 93.8% compared to 85.5% for HM oil. Filtration contributed to a 4-6% recovery in flow rate by reducing contamination from solid particles and water. These outcomes are novel as they highlight the operational benefits of selecting appropriate oil types and applying targeted filtration strategies in industrial hydraulic systems.