Wear Rate Determination for IC Engine Condition Monitoring Results Obtained in an Urban Transport Fleet

This paper is structured into two different parts: Firstly, it describes a methodology to evaluate wear conditions in internal combustion engines in order to go beyond the classical evaluation based on specified wear concentration limits provided by engine manufacturers or commercial oil laboratories. The proposed methodology uses spectrometric wear debris measurement data and typical maintenance data to obtain a more representative parameter of wear condition, defined as “compensated wear rate”, that takes into account particular engine operating conditions affecting wear concentration measurements. Later, an evaluation of this compensated wear rate is carried out using statistical criteria and considering individual engine characteristics such as engine age, type of service, engine metallurgy, environmental conditions of work etc. Secondly, results obtained from an investigation carried out on oil samples from engines of an urban transport fleet are presented, confirming the value of compensated wear rate as a more representative parameter of engine wear behaviour during the oil use period than absolute concentration values.