38. Detection of Excessive Diesel Engine Piston Slap Using Acoustic Emission Signals

This paper presents a study whereby a series of tests was undertaken using a naturally aspirated, 4-cylinder, 2.216 L, Perkins diesel engine fitted with a piston having an undersized skirt. This experimental simulation resulted in engine running conditions that included abnormally high levels of piston slap occurring in one of the cylinders. The detectability of the resultant diesel engine piston slap was investigated using acoustic emission signals. Data corresponding to both normal and piston slap engine running conditions were captured using acoustic emission transducers along with both in-cylinder pressure and top-dead centre reference signals. Using these signals, it was possible to demonstrate that the increased piston slap running conditions were distinguishable by monitoring the piston slap events occurring near the piston mid-stroke positions. However, when monitoring the piston slap events occurring near the TDC/BDC piston stroke positions, the normal and excessive piston slap engine running conditions were not clearly distinguishable.