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Particulate filter is one of the major technologies to meet air pollution environment regulation since the first introduction to market of diesel passenger car in 2000. It is an indispensable part from September 2011 when the particle number of exhaust gas should be limited for new models. This is also a hot issue for gasoline engines with direct injection technology for improvement of fuel economy even though the EURO 6 regulation for GDI gasoline vehicles is not yet finalized. Car OEMs are under development exploring various options. Otherwise this kind of technology has some task to overcome, such as back pressure resulting in a fuel penalty, burden of increased cost and temperature control within the durable limit. The materials for particulate filters have their own characteristics as material itself. The choice of material is heavily dependent upon the control strategy for soot regeneration.

As the use of diesel engines increases in the transportation industry and emission regulations tighten, the implementation of diesel particulate filter systems has expanded. There are many challenges associated with the design and development of these systems. Some of the key robustness parameters include regeneration, efficiency, fuel penalty, engine performance, and durability. One component of durability in a diesel particulate filter (DPF) system is the filter's ability to resist ring-off-cracking (ROC). ROC is described as a crack caused primarily by thermal gradients, differentials, and the resulting stresses within the DPF that exceed its internal strength. These cracks usually run perpendicular to the substrate flow axis and typically result in the breaking of the substrate into separate halves.

The key technical aspects of a catalyzed particulate filter (CPF) system development are software calibration for regeneration and component optimization for system performance. It is important that the optimized component specification be selected an early stage since the components have an effect on the overall regeneration strategy. Accordingly, in a catalyzed particulate filter system the washcoat and precious metal loading are main components that should be optimized at an early stage of the system development. An accelerated aging protocol is needed in order to properly evaluate the performance of various catalyst systems in a timely manner.