The influence of the injection frequency on the urea selective catalytic reduction systems performance

This study presents the influence of the UWS injection frequency on a close coupled SCR systems performance. The investigation was performed with the CFD tool AVL Fire. In the paper the analysis of four different UWS injection frequencies in the three different operating points of diesel engine was shown. The assessments of the system performance was referred to the ammonia distribution at catalyst intake and wall film formation inside the investigated geometry, as these are considered as crucial in such a configuration. The results showed that injection frequency affects both factors on different level depending from the flow conditions. In addition, the wall film crystallization risk was discussed basing on the obtained wall film characteristics