Premature Degradation of Lubricating Oil during the Service Life of the Positive-Ignition Engine

The main purpose of this article is to draw attention to the possibility of uncontrolled degradation of lubricating oil during its routine operation. Such degradation can pose a serious threat to engine operation and can even cause its permanent damage. The research of the work was aimed at determining the rate, size and directions of degradation processes of lubricating engine oil used in a turbocharged positive-ignition engine. After the on-road use in the vehicle, the used oil was subjected to multidirectional tests, and the results obtained were compared with those of equivalent tests of the unused oil. Furthermore, photographic documentation of selected internal engine components covered with deposits was made, and then the sludge collected from them was tested. The results showed that in the case of real (non-optimal from the vehicle manufacturer's point of view) operating conditions, significant acceleration of multidirectional lubricating oil degradation processes in the engine can occur. This necessitates its more frequent replacement. It was also found that systems used by engine manufacturers to monitor oil level and also its quality during operation do not always early enough detect the degradation of lubricating oil to the degree threatening the proper and safe functioning of the engine