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Cavitation erosion on wet cylinder liners has been occurring for many years. However, the higher loads that have been applied to the engines in recent years are enhancing its effects. The material removal during the cavitation occurrence can reduce the engine life considerably, as the liner can be perforated resulting in the mixture of the coolant fluid with the lubricant oil of the engine. This paper discusses the most important points found in a bibliographical review about this subject creating a better theoretical basis for the development of new materials and designs of cylinder liners. The results of the development of a new test procedure to study the cavitation on cylinder liners are also presented, with the objective of reducing the duration and cost of tests in dynamometric benches.

The analysis of the wear resistance of engine components must take into account the whole system. It is of no use to improve the properties of one of the components if it will cause higher wear on the other components of the tribological system. This paper presents a study to improve the wear resistance of piston ring coatings and liner materials at the same time that the compatibility between their wear rates is focused. The diesel engine tests were run with high sulfur fuel (about 0.9 wt%) and lubricant with low total base number (TBN) with the objective of increasing the corrosive conditions. The results show that the best compatibility between the wear rates of the top rings and liners is achieved when the rings are coated by plasma spraying with a molybdenum based material containing approximately 15% of moly carbide and when the liners are made of pearlitic gray cast iron with niobium, vanadium and titanium additions.

The exhaust gases emission regulations, with very restrictive limits, have imposed the need of developments in other areas, among them, in the internal components developments. The necessary maintenance of low levels of oil consumption for long periods of engine use, leads to the development of components with higher wear resistance and higher efficiency. Among these components, the piston rings and the cylinders play an important role in the oil consumption control and also in the engine service life. This paper presents the results of engine tests run to compare the components wear (piston rings and cylinders) when using different types of lubricant oils.