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

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.