<![CDATA[General Background Modern internal combustion engines demand high efficiency and operational durability under severe thermal and mechanical stresses. Specific Background Journal bearings frequently operate under severe loading, transitioning from hydrodynamic to mixed lubrication regimes. Knowledge Gap However, predicting frictional losses remains challenging due to complex interactions between elastic surface deformations, piezoviscosity, and shear thinning. Aims This study presents an integrated methodology combining experimental test-rig evaluations with multi-body hydroelastic simulations to evaluate journal bearing performance. Results Results indicate that while temperature reduces oil viscosity, high hydrodynamic pressures exceeding 200 MPa increase viscosity, whereas shear rates up to 2.2×10⁷ s⁻¹ cause noticeable shear thinning at high speeds. Additionally, initial edge contact stresses decrease rapidly during the running-in phase. Novelty A fully coupled thermo-elasto-hydrodynamic framework incorporating worn surface topographies is established. Implications These insights enable optimized bearing geometry designs and advanced lubricant formulations for high-efficiency engines. Key Findings Highlights Combined hydroelastic simulation and dynamic testing accurately predict journal bearing friction loss. Pressure-viscosity and shear thinning effects significantly influence high-load fluid film stability. Edge wear during running-in rapidly reduces peak contact stress without altering hydrodynamic torque. Keywords : Journal Bearings, Mixed Lubrication, Elastohydrodynamics, Friction Torque, Internal Combustion Engines]]>
