Exhaust purification system of internal combustion engine

Abstract

This exhaust gas purification device for an internal combustion engine is provided with a particulate filter disposed in an engine exhaust system, and a catalytic device disposed downstream of the particulate filter in the engine exhaust system. The catalytic device holds sulfuric acid as a sulfate and releases the product as SO 2 .

1 . An exhaust purification system of an internal combustion engine, comprising a particulate filter which is arranged in an engine exhaust system and a catalyst device which is arranged at a downstream side of said particulate filter of the engine exhaust system, said catalyst device holding sulfuric acid as a sulfuric acid salt and releasing it as SO 2 , regeneration processing being performed to burn off trapped particulate at said particulate filter when an amount of SO 2  adsorption of said particulate filter reaches a set amount, and sulfuric acid which is released from said particulate filter due to said regeneration processing being held by said catalyst device. 
     
     
         2 . The exhaust purification system of an internal combustion engine according to  claim 1  wherein the sulfuric acid salt which is held at said catalyst device is released as SO 2  by heat decomposition. 
     
     
         3 . The exhaust purification system of an internal combustion engine according to  claim 1  wherein the sulfuric acid salt which is held at said catalyst device is released as SO 2  by lowering the oxygen concentration in said catalyst device. 
     
     
         4 . The exhaust purification system of an internal combustion engine according to  claim 1 , wherein said catalyst device is comprised of a substrate on which zirconium oxide or cerium oxide is coated. 
     
     
         5 . The exhaust purification system of an internal combustion engine according to  claim 2  wherein said catalyst device is comprised of a substrate on which zirconium oxide or cerium oxide is coated. 
     
     
         6 . The exhaust purification system of an internal combustion engine according to  claim 3  wherein said catalyst device is comprised of a substrate on which zirconium oxide or cerium oxide is coated.