Development of an Oil Deterioration Monitoring System by Estimating Base Number

In this research project, technology for estimating the base number (BN) deterioration, used as an index for judging engine oil deterioration, was developed. A detailed investigation using a NO_x bubbling unit was carried out, and as a result it was found that the speed at which the BN falls was determined mainly by heat and NO_x. In addition, a detailed analysis was carried out, and it was found that the reduction speed can be expressed using the differential rate law. A study of the possibility of estimating reduction of the BN in an actual engine was carried out using a BN deterioration equation. The results of this study showed that it was possible to adequately estimate the BN deterioration. This indicated that it is possible to estimate the reduction of the BN on-board by the electronic control unit (ECU).