Abstract
Keywords:
WCC, DOC, PM, PM oxidation
Abstract
Modern passenger cars with diesel engines are equipped with DOC (diesel oxidation catalyst) for the purpose of reducing HC and CO. Cold start exhaust emissions can be troublesome here as in gasoline engine vehicles. This caused the WCC (warm-up catalytic converter) to be applied to the diesel passenger cars. In this study oxidation of the particulates in WCC are to be examined. When the HSDI diesel engine with WCC was operated at high speed and over mid- load conditions, the number of maximum released PM was observed at around a 10nm size in diameter. When the temperature of the WCC reached over 300℃, the number of PM having a diameter smaller than 30 nm was sharply increased. The total mass of the PM emission in the rear of the WCC was reduced at low speed and low load conditions by the adsorption of PM on the catalyst. And at high speed and over mid-load conditions, the relatively large PM cracked into a fine PM during oxidation on the WCC, and the mass of fine PM with a diameter in the range of 10-40 nm increased.