Practices of preventive maintenance and replacement for engines: A case study

This paper reports on the application of the sequential method, presented in a previous paper (K.K. Lai, K.N.F. Leung, B. Tao, S.Y. Wang, Journal of the Operational Research Society, submitted), to determine optimal policies of when to carry out a preventive maintenance action for an engine and when to replace an engine in use. The sequential method was run with the real data of engines provided by the Kowloon Motor Bus Company Limited in Hong Kong. First, four functional forms for an engine's lifetime distribution were proposed, the values of the respective distribution parameters estimated, and the goodness of fit of the distributions assessed. Secondly, the values of the corrective maintenance indicator were estimated and some values assigned to the preventive maintenance indicator. Thirdly, the other input values for the method were assessed. Finally, three optimal maintenance and replacement policies with respect to three different criteria were determined, respectively. This case study shows that the sequential method can be used to solve a maintenance and replacement problem efficiently. (C) 2000 Elsevier Science B.V. All rights reserved.