EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To reduce non-burned HC and NOx exhausted to the atmosphere at a warm up operation time extremely. SOLUTION: A three dimensional catalyst 27 is arranged in the branch pipes of exhaust manifolds 19, 20 and an exhaust control valve 24 is arranged in the exhaust pipe 25 of the down stream of NOx absorbent 23. The exhaust control valve 24 is nearly fully closed until NOx absorbent 23 is activated after engine start and the injection amount of a main fuel is increased than the most proper injection amount at the exhaust control valve fully open time and a sub-fuel is additionally injected in an expansion stroke and the air fuel ratio of the exhaust gas exhausted from a combustion room is controlled to a theoretical air fuel ratio.