Abstract:To monitor the fuel content in the used oil quantitatively and rapidly,a serial of lubricating oil samples with different fuel content were made up through gravimetric method,and a standard curve of fuel content with correlation coefficient of 0.987 7 was established based on the FTIR peak area of 804~759 cm-1,which can be used for the quantitative analysis of the fuel content of used lubricating oil.In order to achieve the rapid monitor of fuel content,a calibration model was built with partial least square method (PLS) after pretreating the Fourier transformation infrared spectrometry of prepared oil samples and used ones by Savitzky Golay smoothing and the first derivative.The standard error of calibration model is0.144,the correlation coefficient is 0.986,and the standard error of prediction set is 0.161,indicating that the model has high precision and accuracy can be used to monitor the fuel contaminant of oil rapidly.