Evolution of tribofilms under lubrication conditions experienced in engine valve trains

摘要: A block on ring tribometer employing AISI E52100 steel components, was used to simulate cam and tappet tribology in order evaluate the tribological performance evolution (frictional performance, wear coefficients, surface chemistry species/quantification film structure) tribofilms. Lubricants consisted of a mineral base oil containing zinc dialkyl dithiophosphate (ZDDP) plus full dispersant-detergent-antioxidant package an identical blend but with addition molybdenum dithiocarbamate (MoDTC). Energy Dispersive X-Ray analysis (EDX) X-ray Photoelectron Spectroscopy (XPS) chemical techniques have been employed, allowing crucial link between testing duration properties be evaluated. Factors such as topography due formation hence protection friction control offered, are analysed using Atomic Force Microscopy (AFM). The contrasting frictional difference two lubricants is correlated wear, roughness effects, structure chemistry. relationships running-in service valve train system tribo-chemical parameters this based work discussed. It found that reduction observed primarily consequence tribofilm shear strength changes not nano-scale topography, which comparable magnitude at different coefficients.