| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine capable of inhibiting formation of cyanic acid by appropriately executing urea injection control. <P>SOLUTION: The exhaust emission control device for the internal combustion engine is suitably used for purifying exhaust gas with using a NOx storage reduction catalyst and a NOx selective reduction catalyst. The NOx selective reduction catalyst is provided at a downstream side of the NOx storage reduction catalyst in an exhaust gas passage. The exhaust emission control device for the internal combustion engine is moreover provided with an urea injection means and an urea injection control means. The urea injection means is, for example, an injection valve injecting urea into the exhaust gas passage. The urea injection control means stops urea injection by the urea injection means when catalyst temperature of the NOx storage reduction catalyst and/or the NOx selective reduction catalyst is not more than predetermined temperature. Consequently, formation of cyanic acid can be inhibited and leak of cyanic acid from the NOx storage reduction catalyst and/or the NOx selective reduction catalyst can be inhibited. <P>COPYRIGHT: (C)2009,JPO&INPIT |
