Base Number (BN) Test

CMT´s Bas Number (BN) Test is the test method to test system oil for various diesel engines. The CMT Base Number test uses a modern-day digital test cell, providing quick, reliable results while being user friendly and easy to operate. The reading is relative to a calibration measurement that can be saved in the device. Usually, fresh oil will be used for calibration. However, it is advisable to do a test with oil from the last oil analysis with two-stroke engines. This is important since the leaking cylinder oil will change the additive package and hence change the calibration. The device can store calibrations from 6 different oils and the last reading from each oil type.

Performing a BN Analysis is particularly important for engine oil, as it by design is used to control acidic combustion products by neutralising these before they can corrode engine parts. The Base Number (BN) of your lubricating oils will determine the effectiveness of managing the acids.

To avoid acid corrosion inside a combustion engine, it is essential to maintain a certain alkalinity reserve. Additives (primarily calcium) is added to the oil to neutralise any acid which might build up during the combustion process.