Control of Diesel Catalyzed Particulate Filter System II (The Optimization of Catalyst in the CPF System) 2005-01-0672

To meet EURO 4 diesel passenger car emission regulations, various experiments of a catalyzed particulate filter (CPF) system have been performed with 2.0L common-rail diesel engine.

The main components of a CPF system are a filter and a catalyst, thus we performed the optimization of these two components accordingly. First, we constructed a system with a high porosity silicon carbide (SiC) filter coated with a catalyst washcoat and precious metal loading optimized for performance, cost, etc.

We primarily investigated the effects of the catalyst on the DOC and CPF on the diesel emissions. We performed various catalytic activity experiments in order to verify the effects of filter shape, catalyst washcoat loading amount, precious metal loading amount, aging effects through regeneration, etc. Finally we evaluated the catalytic activities through the European vehicle emission driving cycle (NEDC) mode.

We also established a DOC and CPF aging mode which simulate regeneration conditions on the engine bench. Considering catalyst deactivation specifically, the number of regenerations and the associated catalyst exothermic temperatures were very important factors.