IN-SITU OIL CONDITION MONITORING IN PASSENGER CARS

Oil condition sensors which had a two-electrode structure with an inte rdigitated pattern and roughened electrodes were fabricated using micr omachining techniques. With an AC sawtooth waveform voltage source app lied to the sensor electrodes, a current dependent on the oil conditio n can be measured and converted to a DC voltage output. The sensors we re mounted on the dipsticks of test cars and were used for in-situ eng ine oil degradation monitoring over 20320 km (12700 miles). The durati on of the testing was from winter to summer, and both normal and short distance driving were tested. Measured sensor outputs were also compa red with oil analysis results. There was a strong correlation between the sensor output and the condition of the oil as confirmed by the oil analysis.