The Need for MAN Cat. II for Two-Stroke Marine Engines

Jan 11, 2022
Posted by Ian Bown, Technical Manager, Marine Diesel Engine Oils

The first emission control areas (ECAs) were introduced with a 1% Sulphur fuel in 2010. At that time, 40 base number (BN) cylinder oils were recommended for use in those areas. Moving forwards to 2015 and the introduction of 0.1% Sulphur fuel, MAN ES set a requirement for a lower base number cylinder oil, this is when low BN cylinder oils such as 17, 20 and 25BN were born. When very low sulphur fuel oils (VLSFOs) were introduced in 2020, it became clear low BN cylinder oils were not providing the required level of deposit protection. MAN announced they were focusing on 40BN cylinder oils that had the performance of 100BN oils, in terms of cleanliness and keeping pistons and piston ring packs clean.  In this video, we look back over the past few years and discuss the needs of the market that led to MAN Category II.

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Video Transcript

The first emission control areas or ECAs were introduced with a 1% Sulphur fuel in 2010. At that time, 40 base number cylinder oils were recommended for use in those areas. If we move forwards then to 2015 and the introduction of 0.1% Sulphur fuel, then MAN set a requirement for a lower base number cylinder oil, but one that had the performance in terms of cleanliness, keeping pistons and piston ring packs clean. That's when we first saw the introduction of the low BN cylinder oil, so the 17, the 20 and the 25 and then MAN followed that up on that again in 2020 when the 0.5% Sulphur cap was introduced globally and the VLSFO fuel.

What we were aware of during that period was that the VLSFO fuels were going to be variable in terms of their performance, and this was mainly due to the components that were being used, the blending processes and or the manufacturing process behind the 0.5% and so MAN issued a letter with their intent to revoke the NOL's for some of those low BN products and that outline the procedures that the additive and oil companies would need to go through to approve 40 base number products. During that whole period, we've also got to remember that the engine efficiency was also improving. The engine designers were bringing out more efficient engines, higher pressures, higher temperatures, and actually we end up there with a mix of fuels, cylinder oils, engine design that created almost the perfect storm.