Some Rudiments of Diesel Particulate Emissions

In the future the fuel-efficient passenger-car diesel faces difficult particulate emission standards. To provide a foundation for understanding this problem, four aspects of particulate production in such an engine are considered -- the combustion environment for soot formation, the phenomenological mechanisms involved, in-cylinder oxidation of soot, and the effects of exhaust dilution on the particulate mass collected on a sampling filter. Where significant experimental results from diesel engines are lacking, appropriate non-engine experience is reviewed to contribute additional insight. In the concluding section some practical implications are drawn for the diesel engine.