Wear trend analysis based on ferrograph cover area rates compares with other methods

It is the aim of this paper to analyze the change tendency of lubrication wear particle based on collecting sample for 1000 hours engine reliability test. Traditional method of quantitation ferrograph analysis adopts analog quantity of light intensity. The method has many uncertainty factors(detector and light resource decline, Manmade factors), these makes inaccurate measurement. So this paper introduce a kind of image processing method to analyze ferrography quantitatively. The paper gives a comparison of different kind of oil monitoring methods, such as atom spectrum technology, ferrograph technology and PQP monitoring method. Because of the difference of their basic theory, their sensitivities are different according to the change of particles size. Based on analyzing the tend of wear particle concentration with the difference methods, some results of analysis are different and some result are approximate. Ferrograph technology is sensitive to wear particles with their size change from a few microns to hundreds microns. Atom spectrum method is sensitive to small particles with their size smaller than a few microns. Therefore, atom spectrum technology is sensitive to small particles and ferrograph technology is sensitive to large particles. Both of large wear particle concentrations and small wear particle concentrations are increasing synchronically at times. Both show inverse proportion sometimes. Difference methods could give difference analysis tools for machine running condition.