| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine equipped with an NSR catalyst and SCR capable of accomplishing a high NOx purification rate by combination of the NSR catalyst and SCR regardless of degrees of deterioration of the SCR. <P>SOLUTION: The exhaust emission control device of the internal combustion engine 10 capable of lean operation is equipped with a NOx storage reduction catalyst (NSR catalyst) 16 arranged in an exhaust passage 12, a NOx selective reduction catalyst (SCR) 18 installed downstream of the NSR catalyst 16, a deterioration judging means to judge whether the SCR 18 is deteriorated, an exhaust heat recovery device 20 capable of changing the bed temperature of the NSR catalyst 16, and a control means to control the bed temperature of the NSR catalyst 16 into the reference temperature region (350-450°C) when judgement is made that no deterioration is generated in the SCR 18, and when the SCR 18 is deteriorated, the bed temperature of the NSR catalyst 16 is changed into the prescribed low temperature region (250-350°C). <P>COPYRIGHT: (C)2012,JPO&INPIT |
