A New Sensors Array for the Measurement of the Content of Fuel Dissolved in the Engine Oil

The maintenance on condition is gaining more and more importance in the field of vehicle pool management. A crucial role in the vehicle maintenance is covered by the changing of the lubricating oil of the gearbox, the differential and the engine. In the lubricating oil different substances dissolve: metal traces from the mechanical parts as well as soot and fuel traces from the leakages unavoidably present in the moving parts of the engine. As well known, the oil loses its lubricating characteristics according to the content of the above contaminants. The aim of the present work is therefore to test a new sensors array whose function is to reveal the diesel fuel content in the lubricating oil. The array consists of different gas microsensors based on different metal oxide thin films deposited by sol-gel technique on silicon substrates. During the tests, the fuel percentage present in the engine oil was varied on different levels and all the sensors were exposed to the volatile compounds deriving from the engine oil samples contaminated by fuel. The sensor array resulted appreciable sensitive to the volatiles of the different engine oil samples giving different patterns of responses suitable for data analysis. In particular, Principal Component Analysis (PCA) applied to the sensor response data-set gave a first proof of the sensor array capability to discriminate among the differently contaminated by fuel.