Development of a radiometric technique for measuring lubricating oil consumption in an I.C. engine

Abstract

A radiometric technique employing 131I-tagged lubricating oil was developed which affords continuous measurement of the oil consumption in an I.C. engine down to less than 1·0 g/hr. The half life, emission characteristics and certain other factors make 131I a very suitable tracer. The exhaust gas from the engine passed through potassium iodide solution in an extraction tower. This solution is circulated through a counting chamber and its activity measured with a KI (Th) scintillation detector and recorded continuously. The rate of activity rise is a measure of the rate of oil consumption. Calibration is done by using tagged fuel instead of oil and measuring the rate of activity rise of the extracting solution, the rate of fuel consumption being known. The lubricating oil consumption rate was measured in a small diesel engine by this technique at various operating conditions. The results obtained with 4–6 hr test compared favourably with those obtained with 300–400 hr of conventional tests employing the drain weigh method.