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Investigations of the Usefulness of Dilatometric Methods in the Diagnostics of Combustion Engines

Due to rapidly progressing development in the field of materials used in the automotive industry, research methods enabling the validation of the properties of materials used in specific applications, e.g., engines, are gaining importance. One such method is dilatometry, which belongs to a branch of physics dealing with methods of measuring the thermal expansion of bodies. It includes assessment study of the dependence of body measurements on external conditions. The authors propose that dilatometric methods could be used to diagnose damage and the causes of engine damage that has already occurred. This is a novel approach in diagnostic methods. The aim of the paper was to validate the proposed method for diagnosing of combustion engine components. Two cases of malfunction of this type of device are presented. In the first case, the subject of research is needle-nozzle holder precision pairs used in engines with a power of 150 kW. The main achievement of the research is revealing the occurrence of different thermal expansion values of the materials in the individual nozzle holders, with specific needles in particular causing adverse changes in clearances between these elements. The other case involved tests with respect to engine pistons. The proposed test method allows for a very accurate and relatively quick determination of the degree of damage to their surface. The conducted research confirms the usefulness of dilatometric methods in diagnosing combustion engines—their application makes it possible to determine the causes for the formation of the irregularities. The presented results are promising and enable further development of the methods and their implementation not exclusively with regard to internal combustion engines.