EXHAUST EMISSION CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of highly accurately diagnosing the deterioration in a three-way catalyst under a wide range operation condition including an acceleration operation area.

SOLUTION: This exhaust emission control device is provided for purifying combustion exhaust gas exhausted from an internal combustion engine. The exhaust emission control device 1 has the three-way catalyst 2 arranged inside an exhaust flow passage 4 of the internal combustion engine, and the detectors 3 capable of continuously measuring the concentration of nitrogen oxides included in the combustion exhaust gas on the upstream side and the downstream side of the three-way catalyst 2 inside of the exhaust flow passage 4. The exhaust emission control device 1 can diagnose a deterioration degree of the three-way catalyst 2 by a variation in the concentration of the provided nitrogen oxides by measuring the concentration of the nitrogen oxides included in the combustion exhaust gas on the upstream side and the downstream side of the three-way catalyst of the exhaust flow passage.

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