What Does Total Base Number Mean in Oil?
Total Base Number (TBN) of a lubricant indicates its ability to neutralize contaminants such as combustion byproducts and acidic materials. It is a measure of (alkaline) additives in the oil.
Higher-TBN oils are able to neutralize a greater amount of acidic materials, which results in improved protection against corrosive reactions. TBN levels are targeted for the intended application. For example, gasoline engine oils typically display lower TBN numbers, while oils in a diesel engine must manage the high contaminant-loading from soot and sulfur and typically run higher. TBN levels decrease as the oil remains in service. When the level reaches a point where it can no longer protect against corrosion, the oil must be changed. Oils that are formulated specifically for extended drain intervals typically display elevated TBN numbers to ensure proper corrosion protection for the duration of the extended interval.
TEST (ASTM D2896) The Base Number Test measures the detergents and dispersants in new oils.
Detergents in Engine Oil
Detergents are additives that clean and prevent contaminants from adhering to parts. Detergents are used in motor oil to reduce deposit formation and neutralize acids.
Dispersants in Engine Oil
Dispersants are additives that keep contaminants in suspension and away from engine parts. The key benefit of suspending the contaminants is the prevention of sludge formation which keeps the engine parts clean.
AMSOIL Advantage Regarding Total Base Number
High TBN AMSOIL lubricants contain consistently high TBNs (Total Base Numbers), they neutralize acidic contaminants formed during the combustion process and keep these contaminants in suspension to prevent corrosion. AMSOIL lubricants use detergent and dispersant additives to significantly reduce sludge and carbon deposit formation better than conventional oils.
Useful Links
ASTM D2896-21 – Standard Test Method for Base Number of Petroleum Products by Potentiometric Perchloric Acid Titration