Abstract
This study aims to analyze the used lubricating oil of small Diesel engines under different conditions in order to monitor their instant health condition, indicate their useful life, and provide early warnings of failure progress. It is an attempt to monitor different oil properties together with oil contaminants to diagnose the possible failures before occurring and identify their root causes. It is an effective tool in the case where there are no historical data records for the engines. Specifically, used lubricating oil samples from eight Diesel-powered engines are analyzed as an important information source for early failure detection and decision support. Oil properties; kinematic viscosity, density, and total acidic number (TAN) were analyzed. Also, oil contaminants; wear debris particles, soot, and water content were also elucidated in attempting to predict engine health conditions, wear mechanisms, and useful life. Scanning Electron Microscope (SEM) was used to analyze the wear debris particles. The root causes of engine failure were specified using the 5 Why's method, and interviews with specialists, while the results were schematically presented using the Fishbone diagram. The analysis of oil viscosity showed that engines of high capacities performed better at high operating temperatures than small engines. Besides, the large oil imperfections are not directly related to the oil viscosity reduction but to the high oil TAN and the type and concentration of the oil impurities. This work analysis could assist in robust decision-making on the engine health condition, service life, and maintenance activity that should be applied. (C) 2022 Jordan Journal of Mechanical and Industrial Engineering. All rights reserved