Abstract
In this study, so as to meet the SULEV (Super Ultra Low Emission Vehicle) regulation, the main idea has been focused on the utilization of HCA (Hydrocarbon Adsorber) in order to adsorb the excess hydrocarbons emitted during a period of engine cold-start. As main recipes of HCA materials, many types of zeolite as well as the combination of alumina, precious metals were used. Representative physico-chemical factors of zeolite such as acidic and hydrophobic properties have been characterized and tried to find the optimum recipe of HCA materials. As results, among the acid properties of zeolites, the Si/Al ratio has found to be the most important factor to get higher hydrocarbon adsorption capacity.