Oil total base number
Base number (BN) is a property used to monitor combustion engine oils. It is defined as the oil's ability to neutralize acids that are formed as a byproduct of combustion, chemical reactions and oil degradation. Typically, the higher the BN, the more acid it will be able to neutralize. New engine oils usually have a BN range of 5 to 15. The Base Number (BN) is a measure of the alkalinity of the oil. It is a measure of the effective additive content and thus reflects the oil’s detergent, dispersant and anti-rust properties. The engine manufacturer normally specifies the minimum acceptable BN.