Prediction of instantaneous exhaust particulate concentrations

Gaseous emissions usually are available on a continuous basis from diesel vehicle emissions testing, but particulate matter (PM) emissions are usually only available as a single mass number over a test cycle. Continuous PM emissions are valuable for conformity and hot-spot analyses to support roadway project design and to determine the engine-out PM for after treatment retrofit projects. For diesel vehicles without particulate filters one may argue that carbon monoxide and hydrocarbon emissions may be correlated with the elemental carbon and organic carbon fractions in their exhaust. Methodologies for predicting instantaneous PM production rate from heavy-duty diesel vehicles were developed. These methodologies used combinations of instantaneous and idle carbon monoxide and hydrocarbon production rates with integrated PM production to predict instantaneous PM production rates for each specific vehicle. Comparison of results produced by these methodologies with measured PM productions rates is presented. Apportioning total PM mass over a period of vehicle activity using gaseous emissions is shown to be reliable.