| 摘要 |
PURPOSE:To prevent catalytic degradation by providing an inflow quantity reducing means to reduce inflow quantity of exhaust gas flowing from an internal combustion engine to a catalyst, and providing a control means to reduce the inflow quantity of the exhaust gas to the catalyst. CONSTITUTION:Purification of exhaust gas is performed by a catalyst 12 provided on the way of an exhaust passage 10 of an internal combustion engine 2. An inflow quantity reducing means 14 to reduce inflow quantity of exhaust gas to flow from the internal combustion engine 2 into the catalyst 12 is provided. A control means 16 which operates the inflow quantity reducing means 14 during a deceleration time so that the inflow quantity of the exhaust gas into the catalyst 12 is controlled to be reduced is also provided thereto. An EGR passage 18 by which the exhaust passage 10 to return the exhaust gas discharged from the internal combustion engine 2 to an intake system and an intake passage 6 are communicated with each other is further provided. An EGR valve 20 is interposed on the way of the EGR passage 18. The control means 16 opens the EGR valve 20 when fuel is cut during the deceleration time so that the exhaust gas is controlled to be returned to the intake system. Thus, catalytic degradation is prevented. |
