엔진오일 유전상수 변화량 측정에 의한 엔진오일 품질 모니터링 시스템 개발

Abstract

Dept. of Automotive Engineering, Hoseo University(Received March 15, 2011; Revised April 20, 2011; Accepted April 25, 2011)Abstract − The purpose of this study is to develop an engine oil quality monitoring system to warn the abnormalcondition of engine oil. To do this, first of all, it is needed a personal controller development to measure thecapacitance of a pre-developed engine oil deterioration detection sensor integrated with an oil filter. To measurethe capacitance of engine oil in the sensor, it is used the way measuring the electric charging time in a capacitorby impressing DC volt. This method has merits on cost and signal stability. The measured capacitance is com-pensated by comparing with the one measured by an impedance analyzer. Also, using the dielectric constantgained by an impedance analyzer, the calculating equation of the dielectric constant of engine oil related withthe currently developed sensor is decided. Then, the deterioration degree of engine oil is estimated according tothe change rate of dielectric constant between green oil and used oil. Finally, using this dielectric constant infor-mation together with engine oil temperature and pressure, the currently developed engine oil quality monitoringsystem is to tell the abnormal state of engine oil.Keywords − engine oil deterioration detection sensor(엔진오일열화감지센서), capacitance(정전용량),dielectric constant(유전상수), oil filter(오일필터)