Oil monitoring for diesel engine based on correlation coefficient
                                                    TIAN Hongxiang, LI Jing, SUN Yunling, WU Xiangjun
                                  (College of Power Engineering, Naval University of Engineering, Wuhan 430033,China)

Abstract: Aiming at the problems of oil monitoring for diesel engine used as marine main engine, 36 routine oil samples were taken from 4 same model diesel engine of a ship. Each diesel engine worked continuously for more than 1 900 hours. By means of the instrument of atomic emitting spectroscopy, lubricating oil field rapid viscometer, magnetic debris monitor and crack moisture meter, all oil samples were analyzed. The analysis data were mined based on correlation coefficient method. The significant correlations between parameters were studied at 99% confidence probability. The results show that the negative correlation coefficient between the viscosity of the lubricating oil and the working time of the diesel engine, reveales the failure of the lubricating oil diluted by fuel and the positive correlation of element iron, chromium and copper in the oil samples reflectes the main friction pairs, such as piston assembly and cylinder sleeve, crankshaft and bearing, camshaft and bearing, etc.

Key words: diesel engine; lubricating oil; monitoring; atomic emitting spectroscopy; correlation coefficient; wear