Correction strategies of debris concentration for engine wear monitoring via online visual ferrograph

Abstract

Changing or replenishing the oil in an engine influences the accuracy of oil monitoring. An online visual ferrograph (OLVF) was used to monitor engine wear in this study. The variation in the debris concentration in an engine lubrication system was studied, and its equilibrium concentration of debris was determined to correct the data acquired using an OLVF after fresh oil was added to the system. This correction made the monitoring data of OLVF continuous, thereby enabling the raw data collected before and after oil replenishment to be compared. Changing the oil caused an interruption in the raw data. By combining different prediction modes, a comprehensive trend prediction framework was constructed to correct the data acquired after the engine's oil was changed. Thus, the data acquired before and after the oil change could be analysed and compared. In addition, the engine's whole wear trends could be observed. This correction strategy could also be used to assess the engine's health and to predict its degradation trend.

A microfluidic device for three-dimensional wear debris imaging in online condition monitoring

“…In order to capture wear debris images, the oil flow channel is made up of two pieces of glass constructed as a microrectangular channel. 22 The equivalent diameter of the channel can be calculated using…”

“…The oil flow channel is designed in a millimetre-scale according to the size distribution of wear debris, and the flow rate of a digital pump used for oil transmission is controlled in the range from 0 to 10 mL/min. 22 Thus, the Reynolds number is far less than 2300 and the fluid in the microchannel flows in the laminar mode ( Figure 2). (The lubricant brand used in this study is ''MOBIL LUBRICANT 15W-40'': l ¼ 850 kg/m 3 and ¼ 0.081 PaÁs.)…”

“…Online image-based WDA using their morphological features has been rarely reported in accessible literatures. Currently, two typical available sensors are the online visual ferrograph (OLVF) 22 and the LaserNet Fines (LNF). 23 The OLVF system uses a magnetic force to attract wear debris in oil flow to a planar surface.…”

Modeling and experimental investigations on the relationship between wear debris concentration and wear rate in lubrication systems

“…With the development of predictive maintenance, a variety of machine condition monitoring techniques have been widely used by the industrial enterprises [1][2][3][4]. Wear debris monitoring is an effective approach for revealing the wear condition of a machine without disassembly [5][6][7]. This method can provide important symptom to decision makers at an early stage, eliminate the need for costly machine shutdowns for inspection, and avoid the possibility of catastrophic component failure in service [8,9].…”

“…However, the wear debris concentration in a practical lubrication system is influenced by many factors, such as wear debris removal, oil consumption, oil replenishment and harsh working conditions, etc. The wear debris concentration is mixed with some "noise'' caused by the interferences mentioned above [6].…”