Acoustic Emission Sensing for Maritime Diesel Engine Performance and Health

Monitoring and analysis of high frequency acoustic emissions on marine diesel engines may indicate their condition with the aim to increase engine availability and reduce maintenance overheads for the Defence Force. An experimental study was undertaken to evaluate the application of acoustic emission (AE) sensing to the monitoring of both petrol and diesel internal combustion engine operating condition and health. A commercial-offthe-shelf AE monitoring system and a purpose-built data acquisition system were employed in this study, and an array of digital signal processing techniques were drawn from the literature, adapted and applied to this application. Acoustic emission signals from engine-mounted sensors were able to distinguish load conditions and a failing injector, but large increases in big end bearing clearance were not definitely identified from the acoustic emission signals. DST Group recommends that for any subsequent work that the following is considered: 1. Select an overall diagnostic framework (e.g. permanent or temporary, nature of the system being measured, diagnostic method and sensor type), 2. Define a context using a failure modes, effects and criticality analysis (FMECA), and define good AE candidates, 3. Wherever possible characterise AE signatures by constructing simple isolated component test rigs with seeded faults, 4. Apply the technology directly to the engine of interest, 5. Assess the diagnostic performance of various signal processing techniques, and 6. Partner with research institutions with specialist AE knowledge.