Piston Ring Cylinder Liner Scuffing Phenomenon Studies Using Acoustic Emission Technique

In spite of being a popular topic in technical publications, scuffing between a piston ring face and the cylinder liner is an extremely unpredictable and hard-to-reproduce phenomenon that significantly decreases engine performance. The scuffing phenomenon described as the transfer of cylinder liner particles to piston ring surfaces due to inadequate lubrication and high temperature at top dead center could significantly decrease engine performance. The mechanism of scuffing origin and subsequent catastrophic seizure usually is evaluated by coefficient of friction measurements. The purpose of this paper is (1) to examine the usefulness of acoustic emission RMS measurements generated during testing that results from the friction between piston ring and cylinder liner segments and (2) to establish the relationship between such signals and different levels of the scuffing phenomenon.

Metrological measurements and scanning electron microscope examinations prove that the first peak (spike or flash) in the RMS data is associated with the initial transfer of iron particles from the cylinder liner to the piston ring surface.

The results of the acoustic emission measurement suggest 3 different, easy-to-measure levels of scuffing damage between piston ring and cylinder liner.