Influence of Electrode Design on Electrochemical Impedance Response in Oil to Improve Engine Life
Michael F. Hurley, Darryl P. Butt
Engine lubricant performance degrades due to contamination by water, carbon combustion products, wear particles, and oil oxidation from harsh engine operating conditions. Behavior of interdigitated micro-sensors and macro-sensors were studied to optimize their performance from electrochemical measurement techniques in oil, with the eventual goal of minimizing engine part wear and extending engine life. These sensors were used to characterize impedance behavior of standard oils with known concentrations of additive metal particles, wear metal particles and extent of oil oxidation. Both types of sensors showed that the impedance response of oil increases with increasing concentration of additive metals and wear metals and is affected by Total Acid Number (TAN.) Based on the response obtained from both micro-sensor and macro-sensors, measurement sensitivity is being studied to optimize sensor geometry to support development of a versatile in-situ health sensor to detect oil degradation in real time.