Exhaust purification system of internal combustion engine

Abstract

An exhaust purification system of an internal combustion engine which is controlled so that a combustion air-fuel ratio becomes lean at the time of ordinary operation, provided with an adsorption part which adsorb unburned fuel which is contained in exhaust gas and an oxidation part which has catalyst particles of a metal which oxidizes carbon monoxide. The adsorption part includes zeolite which substantially adsorbs the lower olefins which are contained in the exhaust gas. The adsorption part and the oxidation part are arranged so that the exhaust gas contacts the adsorption part, then contacts the oxidation part.

1 . An exhaust purification system of an internal combustion engine which is controlled so that an air-fuel ratio at the time of combustion at the time of ordinary operation where an engine body outputs a torque becomes lean, the exhaust purification system of an internal combustion engine provided with
 an adsorption part which adsorbs unburned fuel which is contained in exhaust gas when a temperature is less than a release temperature of the unburned fuel and releases the unburned fuel when the temperature is the release temperature of the unburned fuel or more and   an oxidation part which has catalyst particles of a metal which oxidizes carbon monoxide which is contained in the exhaust gas,   the adsorption part being comprised of β-zeolite which adsorbs lower olefins which are contained in the exhaust gas and does not include a zeolite other than β-zeolite, the adsorption part and the oxidation part being arranged so that the exhaust gas contacts the adsorption part, then contacts the oxidation part.   
     
     
         2 . An exhaust purification system of an internal combustion engine as set forth in  claim 1 , wherein
 the adsorption part and the oxidation part are stacked on the surface of a base member, and   the oxidation part is arranged at the side farther from an engine exhaust passage than the adsorption part.   
     
     
         3 . An exhaust purification system of an internal combustion engine as set forth in  claim 1 , wherein
 the adsorption part and the oxidation part are arranged along the direction of flow of the exhaust gas, and   the oxidation part is arranged at the downstream side from the adsorption part in the direction of flow of the exhaust gas.   
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . An exhaust purification system of an internal combustion engine as set forth in  claim 1 , wherein
 the metal particles of the oxidation part are mainly comprised of platinum.   
     
     
         7 . An exhaust purification system of an internal combustion engine as set forth in  claim 6 , wherein
 the metal particles of the oxidation part are formed substantially all from platinum.   
     
     
         8 . (canceled) 
     
     
         9 . An exhaust purification system of an internal combustion engine as set forth in  claim 1 , wherein
 the catalyst particles of the metal of the oxidation part are comprised of metal particles other than metal particles which have an oxygen storage ability.