| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of precisely determining the function state of a NO<SB>X</SB>purifying device by precisely detecting NO<SB>X</SB>contained in exhaust gas. <P>SOLUTION: In this NO<SB>X</SB>detector and the exhaust emission control device using it, a NO<SB>X</SB>sensor 26 comprising a detection element for detecting NO<SB>X</SB>in exhaust gas and a metallic cover for covering the detection element, and an oxygen concentration detection means 24 for detecting the oxygen concentration in the exhaust gas reaching the NO<SB>X</SB>sensor 26 are arranged in an exhaust gas passage 22 for passing the exhaust gas discharged from a combustion means. When the oxygen concentration detected by the means 24 is within a prescribed range, the related value of NO<SB>X</SB>concentration is estimated based on the output of the NO<SB>X</SB>sensor 26 by an NO<SB>X</SB>estimation means. <P>COPYRIGHT: (C)2004,JPO</p> |
