Marine high - speed reciprocating internal combustion engines investigations using envelope vibration method

The article presents some current diagnostic methods for high-speed marine internal combustion engines in operation. A new exploitation strategy of marine diesel engines (Condition Based Maintenance strategy) requires having a substantial amount of information about the condition of the engines and the most important machinery and systems in conjunction with them. In the case of high-speed diesel engines, which usually are not factory-fitted with indicating valves, to assess the combustion process, to assess the technical condition and tightness of cylinders and tuning of fuel and valve gear systems can be used other methods such as vibro-acoustic. Test methods of technical condition assessment of the main propulsion engines and auxiliary engines on the basis of low- and high-frequency changing engine operating parameters and on the vibration processes accompanying such processes have been discussed in the paper. Vibration methods are of particular importance when engines are not equipped with cylinder pressure valves. The possibilities offered by the diagnostic method based on the angular selection of the vibrations accelerations envelope in the diagnosis of high-speed marine engines are also presented