cylinder lubrication and cold corrosion 2013

Cylinder Lubrication & Cold Corrosiony

1< >MAN Diesel & Turbo Cylinder Lubrication & Cold Corrosion 31.01.2013


A severe debate is ongoing in the maritime media on the subject of cylinder lubrication.

MAN Diesel & Turbo’s Views are summarized on the following slides.


Cylinder Lubrication & Cold Corrosion

The process of developing one cylinder lube oil that could lubricate the cylinders regardless of the sulphur content in the

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lubricate the cylinders regardless of the sulphur content in the fuel was started by the oil companies in order to simplify the lubrication process onboard the ships as well as the logistics of supplysupply.

Such oils have BN levels which are lower than the t diti l BN 70 li d l b iltraditional BN 70 cylinder lube oils.

Such oils have performed acceptably in the service tests made.

These oils can very well be used in the vast majority of older MAN Diesel & Turbo engine designs which do not suffer from cold corrosion.



MAN Diesel & Turbo recommend to use a cylinder lube oil

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MAN Diesel & Turbo recommend to use a cylinder lube oilcharacterised primarily with its BN number and SAE viscosityand to use a feed rate according to BN in the cylinder oil andsulphur in the fuel (see our Service Letters)sulphur in the fuel (see our Service Letters).

MAN Diesel & Turbo are aware that some engines may beoperated satisfactorily at even lower feed ratesoperated satisfactorily at even lower feed rates.

A new Service Letter which will describe how the cylinder lube il f d t f th b ti i d i d tioil feed rate can further be optimised is under preparation.



MAN Diesel & Turbo has lately concentrated on further enhanced fuel efficiency

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enhanced fuel efficiency.

In order to improve the specific fuel oil consumption, the pressure in the combustion chamber has been increased on the newest engine designs, especially at low load.

This pressure increase together with the increased operating time at low load has led to increased water and acid condensation on the cylinder walls.

This may lead to cold corrosion in the combustion chamber.



Also the most recently developed part-load and low-load tuning options utilises increased combustion chamber pressure as the

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options utilises increased combustion chamber pressure as the main tool to secure low SFOC (Specific Fuel Oil Consumption) at part load – and may experience the same results.

These part- and low-load fuel tuning options could be:

T b Ch t t (T/C t t) Turbo Charger cut out (T/C cut out)

Waste Heat Recovery (WHR )

Variable Turbine (VT)

Exhaust Gas By-pass (EGB)



In conclusion of the above MAN Diesel & Turbo recommend that:that:

Our newest engine designs (Mk. 9 & G-type engines) are lubricated with cylinder oils having at least a neutralisation abilit as the traditional BN 70 c linder l be oils i e BN 70 100ability as the traditional BN 70 cylinder lube oils, i.e. BN 70-100, preferably SAE 50.

Also MAN Diesel & Turbo’s remaining engine types, if part-load and low-load, fuel-optimised, may require increased neutralisation ability in the cylinder lube oil.

This may be obtained either by increased lube oil feed rate or by using lube oils with higher BN.


Disclaimer

All data provided in this document is non-bindingAll data provided in this document is non binding. This data serves informational purposes only and is especially not guaranteed in any way. Depending on the subsequent specific individual projects, the relevant data may be subject to changes and will be assessed and determined individually for each project. This will depend on the particular characteristics of each individual project, especially specific site and operational conditionssite and operational conditions.


cylinder lubrication and cold corrosion 2013

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