| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device that can efficiently purify NOx contained within exhaust gas without losing an effect of improving a fuel consumption and degrading an emission performance by a fuel cut or a stop of an internal combustion engine. <P>SOLUTION: The exhaust emission control device includes an NOx capturing catalyst 42 provided in an exhaust pipe 4 of an engine 2 and for capturing the NOx contained within the exhaust gas when an air-fuel ratio of the exhaust gas is lean, a three-way catalyst 43 provided in the exhaust pipe 4 at downstream of the NOx capturing catalyst 42 and for purifying the NOx contained within the exhaust gas, and an exhaust gas air-fuel ratio controlling means for controlling the air-fuel ratio of the exhaust gas. The NOx capturing catalyst 42 includes at least Ag and is configured by including a carrier made of oxide. When a predetermined condition is satisfied, the exhaust air-fuel ratio controlling means controls the air-fuel ratio of the exhaust gas to be lean for a predetermined time period after returning from the fuel cut where a fuel supply to the engine 2 is stopped or for a predetermined time period after restarting the engine 2. <P>COPYRIGHT: (C)2011,JPO&INPIT |
