The Influence of Packaging Structure on the Ignition Performance of DOC Catalyst
The existing DOC inlet diversion structure was optimized,and the ignition performance of HC before and after aging of two DOC structures was tested.The ignition,aging process and influencing factors were studied.The results show that the addition of the front rectifier plate can effectively improve the internal temperature and flow field uniformity of the carrier,the maximum flow rate is re-duced from 11.3m/s to 10.6m/s,and the velocity uniformity coefficient is increased from 0.947 to 0.961.During DPF regeneration,there are three states inside DOC:complete ignition,incomplete ignition and non-ignition.With the change of HC injection volume,the three states change with each other.By optimizing HC maximum oil volume limit,large HC leakage or excessive regional high tem-perature can be prevented.The main reasons of non-ignition of catalyst after aging are the excessive local space velocity caused by package structure and the insufficient performance of catalyst after aging.Optimization of flow field distribution or selection of appropri-ate DPF sensor location combined with flow field simulation results during design and development can improve regeneration efficiency and enhance DOC durability.