Stochastic model of truck engine wear with regard to discontinuity of operation

The influence of operational factors on the wear process of the truck engine parts was analysed. Discontinuity of engine operation was found to be a crucial factor. Contribution of start-ups, following breaks in operation in total wear of the engine is significant and in case of investigated engine amounts 40%. As wear of engine parts accompanying a single start-up strongly depends on the temperature, cold start-ups (usually first in the morning) are of particular importance. Taking above into consideration the authors suggest modelling the course of wear as a stochastic process with the following constituents: - transmission process with linear realization representing average value of wear, - stationary process with periodical realization representing deviations of wear intensity in particular seasons accompanying cold start-ups, - stationary process of statistic fluctuations with random time realizations, representing instantaneous deviations of wear in relation to average values. Mathematical model was illustrated with some empirical results.