Home › Knowledge Library › What is TBN and how does it drive cylinder oil selection?
What is TBN and how does it drive cylinder oil selection?
TBN expresses an oil's capacity to neutralise acid, measured in mgKOH/g. In a diesel engine the sulphur in the fuel turns into sulphuric acid after combustion, and the job of the cylinder oil is to neutralise it and limit liner and ring wear.
The link with fuel sulphur
Staying on a high-BN oil after switching to low-sulphur fuel can leave unneutralised base to deposit as calcium compounds. The opposite case — a low-BN oil on high-sulphur fuel — accelerates corrosive wear.
BN selection therefore has to be reviewed whenever the fuel changes, and the feed rate adjusted with it where necessary.
How it is monitored
Remaining BN is one of the standard measurements in used-oil analysis. Read together with iron content and scrape-down analysis, the BN depletion in drain oil shows whether the feed rate is right.
The engine builder's monitoring programme should be the reference, and results interpreted as a trend rather than as single readings.
What it means in practice
Getting BN right has a direct effect on liner life. The suitable product follows from fuel specification, engine type and load profile together; the catalogue covers cylinder oils across the usual BN levels.
Price and availability
Contact us for current pricing, stock availability and delivery times for this product group.
Request a quotation