Pulsed Plasma PM Removal from Diesel Exhaust Emissions. Influences of Reaction Conditions

Influences of space velocity and engine output power on the plasma particulate matter (PM) removal with a dielectric barrier discharge (DBD) reactor have been investigated. The PM removal ratio without plasma discharges is approximately in inverse proportion to space velocity. The PM removal ratio with plasma discharges has been found to be less susceptible to space velocity than that without plasma discharges. As a cause of this result, it is suspected that active oxygen species produced by the plasma discharges transfer with the floating PM within the DBD reactor and then react with the floating PM. The PM removal ratio decreases with the increase in the engine output power, and the more pronounced declination has been found to be observed with the higher discharge electric power. This result is not explained only by the increase in space velocity arising from increasing engine output power. The factors, PM size, PM concentration, and reaction temperature, increasing with engine output power are considered to reduce the effects of plasma discharges on the PM removal.