摘要 |
An exhaust gas purification system includes an adsorbent containing an adsorbent element for adsorbing harmful compounds such as hydrocarbon in an exhaust gas and a catalyst containing a catalyst element for lowering the harmful compounds in the exhaust gas, each disposed in the exhaust gas pipe of an internal combustion engine. When an oxidizing gas is added to the exhaust gas or amounts of combustion gas and fuel are regulated, for a given period, in the process in which the hydrocarbon in the exhaust gas produced at the cold start-up of the internal combustion engine are adsorbed by the adsorbent and desorbed from the adsorbent as a temperature of the adsorbent is increased by the exhaust gas, an exhaust gas composition containing excessive oxygen is provided and the desorbed hydrocarbon are oxidized on the catalyst. With this arrangement, the harmful compounds in the exhaust gas, in particular, the hydrocarbon produced in a large amount at the cold start-up of the engine can be effectively purified. |