Study to develop prediction models to determine the most suitable cylinder lubricating oil feed rates for marine slow-speed engines running on low sulphur fuel oil

• Developed models to determine COFR for marine slow-speed engines using LSFO. • Running with suitable COFR reduces the negative impact of LSFO on engines operation. • The applicability of obtained COFR prediction models was verified. • Application of COFR prediction models will increase cylinder liners’ live time. Since 1 January 2020, the global sulphur content limit for marine fuels has been reduced from 3.50 to 0.50 [% m/m]. Marine engine operators encounter operational challenges concerning using new fuels containing less than 0.5[% m/m] of sulphur. The operation of marine slow-speed engines with low sulphur fuels is associated with an elevated risk of cylinder liner scuffing. Establishing the appropriate cylinder oil feed rates is essential to avoid the potential consequences of using low sulphur fuels. The research was carried out on three slow-speed marine engines in real operating conditions. The paper presents the research results conducted to develop, using a planned experiment methodology and engine scavenge drain oil analysis, a practical aid for the operation of engines with acceptable cylinder liners wear rates and, at the same time, rational total cylinder oil usage. Until now, there has been no clear technical recommendation as to what cylinder lubricating oil feed rates should be used for slow-speed, two-stroke marine engines operating using low sulphur Fuel Oil, considering cylinder liners wear rates. The developed prediction models were verified in the real-life operation of two low-speed engines. Tests confirmed that developed prediction models can be applied in the real operation of engines. Obtained models can be used in the “supervised machine learning” process. Obtained predictive models as operators’ tools to maintain acceptable cylinder liner wear ratios are published for the first time; similar research had not previously been undertaken.