A Featured Baffle Design in Converter Outlet Cone to Manage Exhaust Flow and DEF Droplet Movement for Less Wall Wetting, Better Mixing and Distribution Low Pressure Drop

摘要

A dual DEF system is necessary for meeting LEV Ⅳ MLS emissions with diesel engines. The first DEF injection is designed to operates at relatively low speed/load conditions while the second DEF injection is designed to operate at high speed/load conditions. Designing a Diesel Emission Fluid (DEF) mixing system within limited space becomes very challenge. This invention presents a solution for DEF mixing which needs to happen between two in-line catalytic converter arrangement. The upstream converter can be a Diesel Oxidation Catalytic (DOC) converter or a Diesel Particulate Filter (DPF) or other type of catalysts. The downstream converter can be a Selective Catalytic Reduction (SCR) converter or a Selective Catalytic Reduction Filter (SCRF) which needs DEF solution (urea) as a reductant for SCR catalyst. There is a transfer tube (1) between the outlet cone of upstream converter and the inlet cone of downstream converter. The transfer tube is very short because of packaging constraint. A perforated baffle plate (2) is placed in the outlet cone and a perforated helical plate is placed in the transfer tube (3).