Applying chemometric procedures for correlation the FTIR spectroscopy with the new thermometric evaluation of Total Acid Number and Total Basic Number in engine oils

Abstract

[EN] Currently, the main trend is to employ spectroscopic techniques for the condition assessment of used engine oils. That is a consequence of the requirement for increasing the Oil Condition Monitoring (OCM) efficiency. Usually, FTIR (Fourier Transform Infra-red) Spectroscopy is employed to achieve the ability of measuring used engine oil and uses the FTIR spectrum to generate a relation between attribute-spectrum. To allow this connection, it is necessary to develop chemometric studies. However, this procedure needs a previous validation to correlate the spectrum with the value of the attribute measured by standardised techniques. One of the potential attribute for study is the acidification of the engine oil by the Total Acid Number (TAN), specially employing the ASTM D8045 standard that measures the TAN level by thermometric titration. The new standard offers a better chemical path to quantify accurately the TAN value of used engine oil. And other basic parameter is the Total Basic Number (TBN) that also is possible to quantify by thermometric determinations. Both of these parameters are correlated, therefore this study is focused on the generation of a mathematical model that describes the condition of the engine oil employing the shape of its FTIR spectrum. Specifically, in this work has been shown the applicability of chemometric procedures in conjunction with thermometric titration for determining TAN and TBN values of an used engine oil.