Exhaust gas combustion system

Abstract

An exhaust gas combustion system advances exhaust timing by using an electric CVVT apparatus. The system may include: an air supply passage adapted to provide for passing air to be supplied to an engine; an exhaust manifold adapted to transmit exhaust gas of the engine to an exhaust passage; an air injection passage adapted to connect the air supply passage with the exhaust manifold so as to supply a part of air passing through the air supply passage to the exhaust manifold; and an air valve disposed at the air injection passage so as to selectively open or close the air injection passage. Unburned gas melded in exhaust gas may be combusted according to air supplied to the exhaust manifold.

What is claimed is: 
     
         1 . An exhaust gas combustion system comprising:
 an air supply passage providing passing air to be supplied to an engine;   an exhaust manifold transmitting exhaust gas of the engine to an exhaust passage;   an air injection passage connecting the air supply passage with the exhaust manifold so as to supply a part of air passing through the air supply passage to the exhaust manifold; and   an air valve disposed at the air injection passage to selectively open and close the air injection passage,   wherein unburned gas melded in exhaust gas is combusted according to air supplied to the exhaust manifold.   
     
     
         2 . The exhaust gas combustion system of  claim 1 , further comprising an electric continuously variable valve timing (CVVT) apparatus controlling exhaust timing at which exhaust gas of the engine is exhausted to the exhaust manifold. 
     
     
         3 . The exhaust gas combustion system of  claim 2 , wherein the electric CVVT apparatus is operated to advance the exhaust timing. 
     
     
         4 . The exhaust gas combustion system of  claim 1 , further comprising a supercharger supplying highly compressed air into the air supply passage. 
     
     
         5 . The exhaust gas combustion system of  claim 4 , wherein highly compressed air flow in the air supply passage is supplied by the supercharger such that air of the air supply passage naturally flows into the air injection passage when the air valve is opened. 
     
     
         6 . The exhaust gas combustion system of  claim 1 , wherein unburned gas melded in exhaust gas to flow in the exhaust manifold naturally reacts with oxygen of air supplied to the exhaust manifold by heat of exhaust gas, and combusts.