Hk. Seo et al., Adsorption characteristics of HCA(Hydrocarbon Adsorber) catalysts for hydrocarbon and NOx removals under cold-start engine conditions, KOR J CHEM, 18(5), 2001, pp. 698-703
To meet the SULEV (Super Ultra Low Emission Vehicle) regulations, we have f
ocused on the utilization of HCA (Hydrocarbon Adsorber) in order to adsorb
the excess hydrocarbons emitted during a period of engine cold-start. As ma
in recipes of HCA materials, many types of zeolite as well as a combination
of alumina and precious metals were used. Representative physico-chemical
factors of zeolite such as acidic and hydrophobic properties have been char
acterized and tried to find the optimum recipe of HCA materials. Among the
acid properties of zeolites, the Si/Al ratio has been found to be the most
important factor to achieve higher hydrocarbon adsorption capacity.