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An Experimental Study on the Frictional Characteristics in the Valve Train System
Published October 17, 1994 by Society of Automotive Engineers of China in China
Overall friction torque and the surface temperatures of main parts of the valve train system with Hydraulic Valve Lash Adjuster (HVLA) have been measured in order to examine lubricational behaviors according to changes in running conditions and design variables. The results have shown that rotating speed, spring load and oil temperature act as the main factors influencing the friction losses in the valve train system. From the measured results of surface temperatures,it is known that the cam nose operates in a mixed lubrication regime regardless of rotating speed and spring load, but the lubrication regime of the camshaft bearing, HVLA bore and cam lobe flank, transfers from a hydrodynamic to mixed one with a decrease in rotating speed. From these results, it has been found that the measurement of the surface temperature on each moving part can be used as an effective method for evaluating the lubricational behavior in the valve train system.