Determining threshold values of operating motor oils to diagnose internal combustion engines

Abstract

Technical fluids (engine oil, antifreeze) have to meet their requirements during the standard operating life to ensure the standard service life of combustion engine systems and mechanisms. The stability of the engine oil during engine operation depends on many factors. Motor oil touches all the processes in the internal combustion engine and can serve as a source of diagnostic information, which will make it possible to carry out maintenance and repair of engine parts as needed, to increase the reliability and durability of the internal combustion engine. The results of the oil sample analysis for each indicator allow us to draw distribution density curves for the serviceable and faulty engine condition. Following the results of the analysis, it is necessary to compare the value of the index with its threshold values, separating the zone of operation condition from the zone of the engine faulty condition. Since the number of serviceable engines under operating conditions is always greater than the number of faulty ones, at the first stage of oil quality control, it is possible to determine the threshold values of indicators separating the zone of normal wear (engine serviceable condition) from the zone of increased wear. The research has resulted in an algorithm for calculating and determining the threshold values of motor oils for tractor engines operated on farms in the Omsk region. The authors selected the values based on two oil indicators: kinematic viscosity at 1000 C and flashpoint. The distribution and probability integral of these indicators are better smoothed out by the normal Gauss law. The researchers obtained the maximum and minimum values of indicators corresponding to the 5% boundary of the probability integral.