Assessment of Useful Life of Lubricants Using Analytical Hierarchy Process (AHP) and Vector Projection Approach (VPA)

Abstract

Problem statement: In general, engine oil is usually changed as defined by car or lubricant manufacturers, which is according to mileage. However, it was found from past researches that, at the predefined mileage or timeframe, most lubricant is still acceptably usable and efficient. Approach: This research aimed to calculate useful life of lubricant in order to reach its maximum usefulness. The method of study began by collecting data that indicates deterioration of lubricant by increasing mileage which includes total base number, viscosity, iron and flash point. Then the data was analyzed by means of Analysis Hierarchy Process (AHP). These variables were used to construct a model for calculating appropriate useful life of lubricant by using vector projection approach. It was found from this study that the defined mileage for changing lubricant, which is generally at 5,000 km, is not appropriate. Results: Results of the study suggest that the most appropriate mileage for change of lubricant is at 12,000 km. Conclusion: It could be concluded that collection of data about characteristics of lubricant and use of model for calculating useful life of lubricant can define appropriate interval change of lubricant.