Most studies reported that smoke opacity and particulate matter (PM) are substantially reduced when using emulsion fuel. The goal of this work was to predict the PM reduction of diesel emulsion fuel by measuring the smoke opacity, which is known to be proportional with PM. The smoke/PM measurements were mostly of the particulate trap type, which is lengthy, arduous and only offers cumulative results. In this study, the smoke opacity was measured in real-time by using a smoke opacimeter to obtain faster, simpler and continuous results. The results were compared to the results of Legal Particulate Sampling (LPS). The types of fuel used in this study were an emulsion fuel denoted as E10 and Malaysian EURO2 diesel (D2M). Even though the PM emission of E10 was 20% lower than D2M, the smoke opacity of E10 was 200% higher. It was concluded that the opacimeter could not be used to predict the PM reduction in emulsified D2M.
Keywords: particulate matter, smoke, water in diesel emulsion fuel, opacity, opacimeter.