To provide an exhaust emission control device of an internal combustion engine capable of suitably diagnosing a plugging state of an exhaust emission control member.
The exhaust emission control device of the internal combustion engine comprises, in an exhaust passage 26 of the engine 1, a NOx storage reduction type catalyst 31 and a DPNR catalyst 32 in series along the flow direction of the exhaust gas, a first temperature sensor 33 for measuring the temperature of the exhaust gas immediately after travel through the NOx storage reduction type catalyst 31, and a second temperature sensor 34 for measuring the temperature of the exhaust gas immediately after travel through the DPNR catalyst 32. A controller 25 diagnoses the plugging of the NOx storage reduction type catalyst 31 based on the temperature difference between a first exhaust temperature measured by a first temperature sensor and a second exhaust temperature measured by a second temperature sensor.
MIYAZAKI HIROYUKI
KOBAYASHI SHIGERU
Makoto Onda
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