| 摘要 |
PURPOSE: To block generation of misfire at the time of discharging NOx when the air fuel ratio of exhaust gas which flows in NOx absorbent make in a rich condition or a theoretical air fuel ratio. CONSTITUTION: NOx absorbent 26 is arranged downstream from an exhaust manifold 24, and the exhaust manifold 24 is connected to a surge tank 16 through an EGR gas passage 28. EGR gas is re-circulated when an engine is operated in low and intermediate loads, lean mixture is bunt, and then NOx which is generated at this time is absorbed in NOx absorbent 26. Addition fuel is ejected at the time of an expansion stroke so as to discharge and reduce NO.x which is absorbed in the NOx absorbent 26, and an EGR valve 29 is closed. |
