A System Approach for the Assessment of Cavitation Corrosion Damage of Cylinder Liners in Internal Combustion Engines

Modeling of liner cavitation corrosion is of increasing significance since new engine design trends could aggravate the problem. Cavitation corrosion is of a complex nature and is affected by numerous coupled factors. A system approach to analyze and assess cavitation corrosion damage is deemed necessary. The approach accounts for the macroscopic and microscopic aspects of the phenomenon that include modeling of piston dynamics, liner transient vibration, pressure wave propagation, bubble dynamics and their effect on material damage. Though detection methods can provide crucial insight of factors that influence the cavitation problem, analysis methods are required at the initial design stage to provide overall engine design optimization and reduce prototype development cost and time. This analytical diagnostic approach provides a powerful tool to give valuable and relatively quick insight in solving engine liner cavitation corrosion problems. The approach mentioned above provides a very powerful tool for these purposes.

The source of liner cavitation corrosion has been assumed to be solely due to liner vibration caused by piston impact. However, in some cases block vibration can add an additional source of vibration. Modal analysis and forced transient analysis has been utilized to investigate liner vibration and ways to reduce it. Acoustic finite element analysis has been utilized to model the coupled problem of liner vibrations and coolant pressures. A finite difference integral boundary method was applied to study bubble dynamics and the generation of micro-jet velocities. Finally a mechanism of finer damage and material and coating effects has been investigated.

Several parametric studies have been carried out to help the understanding and the justification for such approaches. The results correlate very well with endurance test experience and expectations. The system approach proves to be necessary and provides a powerful and reliable tool to assess liner cavitation corrosion problems.