Possibility of assessment of operation of sliding bearings in piston-crank mechanisms of diesel engines with regard to load and time of correct work of the bearings by applying acoustic emission as a diagnostic signal

The paper presents a possibility of determining (assessing) operation of sliding bearings with multilayer bushings in crank-piston mechanisms of diesel engines. Properties of load and wear, particularly fatigue and abrasive, are characterized in general. Acoustic emission as a diagnostic signal was proved to be useful for detection of the wear of sliding and barrier layers. Results of measurements of acoustic emission parameters, made with AMSY-5, the 12-channel system, manufactured by Vallen GmbH are presented herein. The measurements include such parameters as: the number of discrete emissions determined by counts of EA events, the effective value (RMS), the number and also the rate per unit of time of oscillating above the threshold level (the number of exceeding the threshold level), amplitude of discrete emission signal, rise time, duration time and damping time of discrete emission, power (energy unit) of discrete emission signal. The usefulness of acoustic emission (AE) application as a diagnostic signal for detection of micro-damage in sliding and barrier layers of bearings in crank-piston mechanisms of diesel engines was confirmed.