| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect air fuel ratio of exhaust gas without large response delay by an upstream side air fuel ratio sensor when fuel is supplied from a fuel supply device for making the air fuel ratio of exhaust gas a desired air fuel ratio. <P>SOLUTION: In an exhaust emission control device for an internal combustion engine provided with an NO<SB>x</SB>catalyst device 10, a linear output type upstream side air fuel ratio sensor 20 arranged on an exhaust gas upstream side of the NO<SB>x</SB>catalyst device, a linear output type or step output type downstream side air fuel ratio sensor 30 arranged on an exhaust gas downstream side of the NO<SB>x</SB>catalyst device, and a fuel supply device 40 supplying fuel to the exhaust gas upstream side of the upstream side air fuel ratio sensor, response of the upstream side air fuel ratio sensor 20 is made quicker than response of the downstream side air fuel ratio sensor 30. <P>COPYRIGHT: (C)2007,JPO&INPIT |
