Modeling and evaluation of the engine oil aging intensity in marine trunk diesel engines when they are supercharged

A computational and experimental model of the aging of lubricating oil in different directions is presented, taking into account the influence on the intensity of its degradation of the degree of forcing (thermal load) and the technical condition of diesel, the quality (motor group) of the lubricant product and the sulfur content in the fuel. The novelty in assessing the aging of the lubricant in a tank diesel engine when forcing it by supercharging consists in the formation of a thermal load on the oil film, which determines the aging rate of the engine oil on the cylinder sleeve of the engine. It is reported how the density of the heat flux acting on the surface of the oil film swept by the piston is experimentally fixed and averaged over the height of the sleeve and the angle of rotation of the crankshaft during the engine operating cycle. The influence of the factors under consideration on the specific rate of aging of lubricating oil per unit area of the sleeve surface in contact with gases in the direction of additive activation, decrease in alkalinity, increase in acidity, tar formation and accumulation of insoluble products has been identified. The lines of equal values of the hypersurfaces of the response functions for the specific intensity of the alkalinity response and the formation of insoluble products of tar formation and acidity growth are illustrated. The requirements for engine oil have been formed according to the level of alloying with multifunctional additives, depending on the degree of boost (average effective pressure) of supercharged marine tank diesels. As a result of the analysis of the aging rate of engine oil in modern marine diesel engines with medium and high boost, the expediency of using unified type oils in them has been confirmed M-10(14)G2CS and M-14(16)DCL20 with multifunctional additives MASK and PMS for the combustion of distillate fuels and their mixtures with fuel oils with a sulfur content of up to 0.5%.