Study on Catalyzed-DPF for Improving the Continuous Regeneration Performance and Fuel Economy 2007-01-0919

It is a big challenge how to satisfy both the purification of exhaust gas and the decrease of fuel penalty, that is, carbon-dioxide emission. Regarding the Diesel Particulate Filter (DPF) applied in the diesel after-treatment system, it must be effective for lowering the fuel penalty to prolong the interval and reduce the frequency of the DPF regeneration operation. This can be achieved by a DPF that has high Particulate Matter (PM) mass limit and high PM oxidation performance that is enough to regenerate the DPF continuously during the normal running operation.

In this study, the examination of the pore structure of the wall of a DPF that could expand the continuous regeneration region in the engine operation map was carried out. Several porous materials with a wide range of pore structure were prepared and coated with a Mixed Oxide Catalyst (MOC). The continuous regeneration performance was evaluated under realistic conditions in the exhaust of a diesel engine.

The Arrhenius plots of the PM oxidation rate during continuous regeneration lead to the conclusion that the enlargement of the continuous regeneration region can be achieved by a high porosity filter that develops deep-bed filtration of the PM. In this way the PM comes more effectively in contact with the catalyst inside the wall and therefore oxidizes at lower temperature due to the contribution of the catalyst.