Precautions for using cylinder oil with low sulfur fuel
July 17, 2023
Engine management is a practical process that combines theory with experience and requires a high sense of responsibility. Below are several issues that need to be noted in the use of engine cylinder oil: Alternate use of cylinder oils with different base values At present, there is no strict international standard for blending ultra-low sulfur fuel oil, but the consensus in the industry is that long-term use of low sulfur oil can lead to poor combustion of the main engine, and the use of BN40 cylinder oil with low alkalinity and poor cleaning performance is more likely to cause excessive carbon deposition in the piston ring and groove.
Adjust according to fuel test report Due to the instability and incompatibility of low sulfur oil, each time a different batch of fuel is used, it is necessary to set the injection method based on the results of the fuel test report. After 1-2 days of replacement use, the scavenging box inspection should be conducted in a timely manner, and the cylinder oil injection rate should be adjusted accordingly based on the results of the scavenging box inspection. Alternatively, low and high alkali value cylinder oil can be used alternately to enhance the cleaning ability of the cylinder oil and control piston ring deposits, Keep the ring clean. Adjustment of oil injection rate Due to the poor cleaning performance of BN40 cylinder oil, some ships maintain cylinder oil injection rates between 1.0g/Kwh and 1.2g/Kwh. After abnormal wear of cylinder liners, some ships even set the cylinder oil injection rate to 1.4g/Kwh or even higher. This result is not only unable to solve the problem of cylinder liner wear, but excessive cylinder oil is more likely to exacerbate cylinder liner wear. According to MAN B&W Energy Solutions Service letter SL2019-671/JAP, in this case, it is recommended to replace the cylinder oil with slightly higher alkaline value based on the inspection of the scavenging box, and appropriately reduce the cylinder oil injection rate. If necessary, the cylinder should be cleaned and relevant components replaced, and the cylinder oil injection amount should be readjusted. Main engine combustion condition Due to the complex characteristics of low sulfur oil, if there is excessive carbon deposition in a single cylinder, in addition to considering the use of cylinder oil, attention should also be paid to the combustion status of the main engine, such as the working conditions of the fuel injectors. If necessary, the fuel injector components should be replaced, and the replaced fuel injectors should be inspected and tested, and maintenance records should be kept. A fuel testing laboratory reminds that when using LSMGO, due to its poor lubrication performance, it is recommended to use fuel additives to enhance its lubrication performance and prevent abnormal damage to diesel engine fuel injection systems, such as fuel high-pressure pumps, injectors, and other components. These are all experiences that can be learned based on actual situations. Analysis of residual oil in cylinder oil During the use of low sulfur oil, the importance of analyzing the composition of residual oil in cylinder oil is highlighted. The composition analysis of residual oil in cylinder oil can reflect not only the chemical environment in which the cylinder liner is located, but also the physical conditions of the piston ring and cylinder liner running in, thereby adjusting the cylinder oil injection rate appropriately. The analysis of residual oil composition in cylinder oil not only provides a visual reflection of the working status of piston rings and cylinder liners, but also serves as the most effective tool for evaluating the wear of the main engine piston rings and cylinder liners, and is an effective means of optimizing the lubrication of the main engine cylinder oil. Reasonable cylinder oil lubrication should maintain a residual oil base value of 10-25mgK
