Exhaust gas purification system for internal combustion engine

Abstract

An exhaust gas purification system includes: at least two catalysts ( 1 a, 1 b ) disposed in parallel with each other on an exhaust gas passage of an internal combustion engine ( 3 ) and having a carrier containing a basic oxide and platinum carried on the carrier; and oxygen supply means ( 2 ) for supplying oxygen to the catalysts ( 1 a, 1 b ).

1 .- 10 . (canceled) 
   
   
       11 . An exhaust gas purification system for an internal combustion engine, comprising:
 at least two catalysts disposed in parallel with each other in an exhaust gas passage of the internal combustion engine and having a carrier containing a basic oxide and platinum carried on the carrier; and   an oxygen supply device that supplies oxygen to the at least two catalysts;   a temperature sensor that detects a temperature of each of the at least two catalysts; and   a controller that determines whether either of the at least two catalysts has deteriorated based on the detected temperature of the catalysts.   
   
   
       12 . The exhaust gas purification system for an internal combustion engine according to  claim 11 , wherein the oxygen supply device does not supply oxygen to all the catalysts at the same time during purification of an exhaust gas, and the exhaust gas is not supplied to a first catalyst while it is supplied with oxygen, and the exhaust gas is supplied to a second catalyst not being supplied with oxygen while the first catalyst is supplied with oxygen. 
   
   
       13 . The exhaust gas purification system for an internal combustion engine according to  claim 11 , wherein the oxygen supply device supplies oxygen to a point on the exhaust gas passage upstream of the catalysts. 
   
   
       14 . The exhaust gas purification system for an internal combustion engine according to  claim 11 , wherein the basic oxide is an oxide of at least one element selected from the group consisting of alkaline earth metals and rare earth elements, or is a complex oxide of zirconia and/or alumina and at least one of elements selected from alkaline earth metals and rare earth elements. 
   
   
       15 . The exhaust gas purification system for an internal combustion engine according to  claim 11 , further comprising:
 a first switching valve that switches the supply of the exhaust gas between the at least two catalysts;   a second switching valve that switches the supply of oxygen from the oxygen supply device between the at least two catalysts; wherein   the controller controls the first switching valve, the second switching valve and the oxygen supply device when it is determined that either of the at least two catalysts has deteriorated based on the detected temperature of the catalysts.   
   
   
       16 . The exhaust gas purification system for an internal combustion engine according to  claim 15 , wherein the controller controls the first switching valve, the second switching valve and the oxygen supply device to stop supplying oxygen to the first catalyst and supply the exhaust gas to the at least two catalysts when the first catalyst, which was determined to have deteriorated, is regenerated. 
   
   
       17 . The exhaust gas purification system for an internal combustion engine according to  claim 16 , wherein the controller controls the oxygen supply device to supply oxygen to the catalyst determined to have deteriorated when a catalyst is determined to have deteriorated and is in a temperature range of 500° C. to 1000° C. 
   
   
       18 . The exhaust gas purification system for an internal combustion engine according to  claim 17 , wherein the controller controls the oxygen supply device to stop supplying oxygen to the catalyst determined to have deteriorated when the catalyst that is determined to have not deteriorated is out of a temperature range of 500° C. to 1000° C. 
   
   
       19 . The exhaust gas purification system for an internal combustion engine according to  claim 15 , wherein the controller controls each predetermined duration of operation of the internal combustion engine, the oxygen supply device and the second switching valve to supply oxygen to at least one of the catalysts, and the first with oxygen. 
   
   
       20 . The exhaust gas purification system for an internal combustion engine according to  claim 11 , wherein an amount of the basic oxide contained in the carrier is 50 wt % or more.