IN-SITU MONITORING OF HIGH-TEMPERATURE DEGRADED ENGINE OIL CONDITION WITH MICROSENSORS

Using proper oils to lubricate an engine is very important. There is a need for a sensor to monitor the condition of the oil to ensure the e ngine is properly protected. In this paper, a microsensor is put in a test engine which is operated at the ASTM Sequence IIIE conditions. Th e sensor has two electrodes with an interdigitated pattern. The spacin g between electrodes is about 5 mum and the sensing electrodes cover 7 mmX7 mm in area. With an a.c. sawtooth waveform voltage applied to th e electrodes, an oil-condition-dependent current can be collected by t he sensor. This current is rectified and converted to a d.c. voltage o utput. Different brands of engine oils are used in the test. Results s how that the sensor has a voltage output that increases with the oil d egradation time. The sensor is able to detect glycol contamination in oil as well.