TECHNOLOGICAL FACTORS AND THEIR INFLUENCE ON THE DURABILITY OF FUEL SYSTEM COMPONENTS

S.Zh. Bodu, A.V. Novoshytskyi, O.P. Shumilov, V.A. Polishchuk A systematic engineering-scientific analysis has been conducted of a complex set of technological factors that directly determine the durability, operational performance, and reliability of the components of diesel internal combustion engine fuel equipment. The primary focus is on the injector nozzle holes as critical zones operating under significant thermal, hydrodynamic, mechanical, and chemical loading conditions. An in-depth assessment of the influence of microgeometry, internal surface roughness, residual stresses, as well as the condition of the inlet and outlet edges of the holes on the development of degradation processes—specifically cavitation, erosion, coking, fatigue, and thermochemical destruction—is conducted. The research methodology is based on a comprehensive synthesis of current theoretical approaches, numerical modeling, experimental observations, and detailed analysis of actual equipment failures. The work compares the effectiveness of various finishing methods: traditional mechanical (drilling, grinding, lapping) and non-contact (electroerosion, electrochemical, anodic-mechanical). It is demonstrated that non-contact technologies ensure high dimensional accuracy, reduction of roughness (down to Ra ≤ 0.02 µm), geometric stability, and minimization of surface damage. It is established that initial defects formed at early manufacturing stages are not eliminated by subsequent operations and significantly reduce the injector’s reliability. Quantitative data on changes in hole diameter, fuel leakage coefficient, hydrodynamic stability, and fuel spray symmetry under real operating conditions are provided. Recommendations are formulated regarding the optimization of the technological processing route, material selection, microrelief control, and residual stress management. The proposed solutions can be implemented in serial production to increase service life, reduce failure frequency, and ensure long-term operational stability of diesel fuel equipment. The presented results have practical applied value for mechanical engineering, and the proposed approach can be adapted to other types of highly loaded components.