Controlling particulate emissions from diesel vehicles

Diesel engines move the world. Their excellent fuel economy makes them the power source of choice in a multitude of applications, such as transportation, excavation and mining. They are used extensively in commercial transport, being employed in trucks, buses, trains and ships. The Diesel engine is also becoming increasingly popular in the passenger car sector, especially in Europe where around 30% of the market is made up of Diesel vehicles; this proportion is expected to increase to 50% by 2010. However, increasing attention is being paid to the particulate matter (PM) emissions from Diesel vehicles, which consists mostly of carbonaceous soot and a volatile organic fraction (VOF) of hydrocarbons that have condensed on the soot. There is growing concern about these emissions, since emerging evidence potentially implicates PM as a major pollutant associated with acute health effects. This article reviews the strategies currently available to control the PM emissions from Diesel vehicles, and outlines the operating principles of the current state-of-the-art systems.