Abstract
In order to clarify the behavior of reductants in a urea-SCR system, two types of diagnostic techniques were developed: one is for measuring NH3, and the other is for measuring total-reductants including unreacted urea and isocyanic acid. These techniques were applied to examine the behavior of reductants at the inlet and inside of the SCR catalyst. This revealed that i) urea to NH3 conversion rates and spatial distributions of reductants at the inlet of the catalyst, and ii) temporal and spatical profiles of urea to NH3 conversion inside the catalyst.
