Modelling of alkalinity changes in lubricating oils used in marine diesel engines

As the time is passing, lubricating oil in marine engine lubricating oil system loses its quality because of oil deterioration process. Lubricating oil quality influences the wear of tribological system elements. The total base number (TBN) is one of the most important oil quality properties. During operation of diesel engines the TBN decreases as alkaline additives are exhausted mainly through neutralization offuel burning acid products. So as to improve lubricating oil properties an engineer uses some maintenance methods. One of these methods is refilling process. The paper presents theoretical researches of total base number changes modelling at various lubricating oil refilling methods. Theoretical model of oil-deterioration process was worked out on the basis ofmass balance equation of total base number. The method of sofaing the problem, structural model of experimental unit, total base number change in case of constant refilling process, calculating example, total base number changes in PIELSTICK12PC2-5V engine oil versus parameter d, percentage changes of total base number in PIELSTICK 12PC2-5V engine oil versus parameter d are presented in the paper.