Catalytic device for stoichiometric air-fuel ratio gasoline engine and catalytic system including the same

Abstract

The present disclosure provides a catalytic device for a stoichiometric air-fuel ratio gasoline engine, in which exhaust gas discharged from a gasoline engine sequentially passes through a WCC (Warm up Catalytic Converter) and a UCC (Under floor Catalytic Converter). In particular, the catalytic device may include an LNT (Lean NOx Trap) component added to one of the WCC and the UCC.

What is claimed is: 
     
         1 . A catalytic device for a stoichiometric air-fuel ratio gasoline engine, in which exhaust gas discharged from a gasoline engine sequentially passes through a WCC (Warm up Catalytic Converter) and a UCC (Under floor Catalytic Converter), the catalytic device comprising:
 an LNT (Lean NOx Trap) component added to at least one of the WCC and the UCC,   wherein the LNT component comprises at least one of platinum and barium.   
     
     
         2 . The catalytic device of  claim 1 , wherein the LNT component is comprised in the UCC. 
     
     
         3 . The catalytic device of  claim 2 , wherein a three-way catalyst is applied to the WCC. 
     
     
         4 . A catalytic system including a catalytic device for a stoichiometric air-fuel ratio gasoline engine, the catalytic system comprising:
 a gasoline engine in which combustion is controlled at a stoichiometric air-fuel ratio;   an exhaust pipe through which exhaust gas is discharged from the gasoline engine;   a WCC (Warm up Catalytic Converter) installed to the exhaust pipe;   a UCC (Under floor Catalytic Converter) installed downstream of the WCC in the exhaust pipe while being spaced apart from the WCC;   an oxygen sensor installed in front of the WCC and another oxygen sensor installed between the WCC and the UCC in the exhaust pipe; and   an ECU (Electronic Control Unit) configured to receive engine data from the gasoline engine and an output value from the oxygen sensors so as to control the combustion in the gasoline engine,   wherein at least one of platinum (Pt) and barium (Ba) is added to at least one of the WCC and the UCC.   
     
     
         5 . The catalytic system of  claim 4 , wherein the at least one of the platinum and the barium is added in the UCC. 
     
     
         6 . The catalytic system of  claim 5 , wherein a three-way catalyst is applied to the WCC. 
     
     
         7 . The catalytic system of  claim 1 , wherein the WCC or UCC including the at least one of the platinum (Pt) and barium (Ba) is configured to store nitrogen oxides (NOx) and to reduce the stored NOx to molecular nitrogen (N2) based on a status of the combustion.