Increasing the durability of the coupling "crankshaft neck - bearing liner" by applying nanocomposite additives to the engine oils of marine medium-speed diesel engines
Increasing the durability of the tribo-couplings of marine diesel engines, which determine their resource, is an urgent problem due to both the safety of navigation and economic factors. The main reason for engine crankshafts failures, which determine the need for major repairs, is the wear of the necks. The solution to the problem of increasing wear resistance and, accordingly, durability is associated with the use of triboactive additives in the lubricant. Despite in-depth and thorough research in the field of application of organo-inorganic materials for use as additives in engine oil to increase the durability of tribo-nodes, it is almost impossible to choose the optimal material for specific conditions, since the studies were carried out for various operating conditions and according to various methods. The purpose of the work is to develop a tribotechnical additive to motor oils that provides an increase in the reliability and efficiency of technical operation of medium-speed marine diesel engines by forming a thin-film metal-ceramic coating on the friction surfaces of steel parts of tribo-nodes, which allows to obtain an optimal set of parameters of the wear-resistant coating material. The paper presents studies of the operational properties of additives in engine oil of 17 organo-inorganic tribotechnical materials of 4 groups - natural and artificial polymers, from which more than 20 compositions and composites were made. It has been established that the most promising is the use of nanocomposites based on vermiculite modified with acid as additives in engine oil, since they have a minimum coefficient of friction with boundary lubrication (0.007-0.014) as well as high wear resistance of 40X steel and provide a minimum wear rate of the bearing liner, thereby increasing the tribo-tension life by more than 3 times, and, accordingly, operating costs are reduced.