COBU

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COBU Project

Cylinder Oil Mixing Unit (COBU)

Cylinder oil is essential for two-stroke engines. Modern cylinder oils are formulated with complex chemistries, which require precise dosage adjustment based on the oil brand, viscosity class and Base Number (BN) level.

Cylinder oil guarantees the right level of detergency and dispersion to keep the rings and piston crown clean, as well as providing the necessary BN to neutralise acids formed during combustion, preventing cold corrosion. The main acid to neutralise is sulphuric acid, derived from the sulphur content in the fuel.

Since the sulphur content and type of fuel vary, two-stroke engines require cylinder oils with the correct BN. However, lubricant suppliers encounter difficulties in supplying multiple specific oils for different BNs, and ships cannot have numerous storage tanks for various grades.

To address this challenge, VTS, in collaboration with Gulf Oil Marine, has developed the Cylinder Oil Mixing Unit (COBU) through a joint R&D project.

The COBU system, designed and prototyped by VTS according to Gulf Oil Marine specifications, enables the mixing of two lubricating oils with different BN levels to obtain an oil with customized BN. The fully automated unit allows mixing, heating and precise measurement of oil consumption.

It can be easily installed on board as a replacement for the heating tank and integrated with the engine control room monitoring system, accessible worldwide through the vessel’s connection.