ELPI Measurement of Particulate Matter from HSDI Diesel Engine with Diesel Oxidation Catalyst

Particulate matter emissions can jeopardize good health. Diesel particulate matter (PM), of diameters less than 10,000nm, was measured from a high-speed direct injection (HSDI) diesel engine by using an electrical low pressure impactor (ELPI). Results were obtained for the smoke level and the PM level (masses and numbers) from this engine by using the ELPI and the Bosch smoke meter, and the results were compared. The effects of a diesel oxidation catalyst (DOC) were also investigated. Under a high speed and high load condition, HSDI diesel engine exhausts a considerable mass of particulate matter with diameter over 100nm, and considerable number of PM from 7 to 100nm at the same driving condition. DOC showed reduction in the total mass of PM, but showed increase in the number of ultra fine PM. At low temperature, before light-off temperature of the soot, the DOC adsorbs the PM, and oxidizes the PM after the light-off temperature. Finely-sized PM could be created during oxidation. Therefore, an advanced DOC is needed to reduce the number of finely-sized PM.