Microsensor Monitoring of Engine Lubricants for Fuel Dilution and Water Content

摘要

A laboratory device has been developed to examine diesel engine lubricants for fuel dilution. Samples of 25 microliters were heated in flowing air, and the volatiles evolved detected with a calibrated electronic sensor. With suitable temperatures and flow rates, determined from tests of typical lubricants and fuels, dilution of 1% was readily detectable. The quantitative precision of the method was affected by the varied oil volatilities, but was limited by the stability of the semiconductor sensor. Moisture sensitivity, flow rate sensitivity, and slowness in returning to its baseline level after use were encountered. A surface acoustic wave fuel sensor might offer improved performance. The detection of small quantities of water in lubricants by this method is difficult, due to the small sample volume and interference by the organic vapors, but should be possible with sensors. Keywords: Fuel dilution, Engine lubricant, Lubricant monitor, Lubricant sensor.