EXHAUST GAS PURIFICATION APPARATUS FOR DECREASING DISCHARGE OF HYDROCARBON DURING COLD START OF INTERNAL COMBUSTION ENGINE

摘要

PURPOSE: To provide an exhaust gas purification apparatus for reducing hydrocarbon emissions during the cold start of the internal combustion engines. CONSTITUTION: This apparatus comprises an adsorber and a catalyst system disposed on its downstream side. The difference between the reaction starting temperature of the catalyst and the desorption temperature of the adsorbent is adjusted to less than 50 deg.C. Zeolites different in temperature dependence are used after mixing them as the adsorbent. Therefore, the emission amounts of contaminating hydrocarbons and carbon monoxide are reduced.