Recording Oil's Vital Signs

Abstract

This article focuses on efforts that are aimed at developing on-board systems to measure oil quality in real time or, at least, to base predictions on specific, observable conditions. A reliable means of monitoring the condition of engine oil will permit a new kind of just-in-time maintenance, and that, according to some forecasters, could save millions of quarts of oil a year. Although car companies schedule oil changes along conservative time frames, some experts say strictly schedule-based maintenance doesn't solve the problems of premature lubrication failure. The article also highlights that an on-board capacitive sensor developed by Kavlico assesses oil quality by measuring the oil's dielectric constant, which increases as molecules break down and additives deplete with use. It is stressed that a combination of measurements will present a truer picture of oil degradation than just one measurement. A combined approach of monitoring driving conditions and using sensors has been taken by DaimlerChrysler of Stuttgart, Germany. The company has developed a passenger car maintenance system, called Assyst, for Mercedes-Benz vehicles. The dielectric number can warn the driver that water is present in the sump or a coolant leak is occurring in the engine.