A new oil condition sensor was designed and fabricated. The newly designed
sensors were installed in three vehicles and tested on the road. The test r
esults indicated that the degradation of engine oil could be divided into t
hree stages: (1) good, (2) rapid increase of total acid number (TAN), and (
3) rapid increase of viscosity. The onset of the second and the third degra
dation stages could be detected by analysing the trend of sensor outputs. T
he performance of the sensor was verified by analysing the oil samples peri
odically collected from the road tests. The oil condition sensor could also
detect water condensation and antifreeze contamination in engine oil. (C)
2001 Elsevier Science B.V. All rights reserved.