| 摘要 |
A Diesel particulate filter (DPF) comprises a wall-flow filter substrate having a mean pore size, an inlet side, an outlet side, and a porous interior there between. A catalyst composition 44 is coated from the inlet side of the substrate to form a catalysed soot filter (CSF), and has a D50 particle size distribution which is less than the mean pore size divided by 4.9 ± 0.1, and wherein the outlet side is substantially free of a catalyst coating. The mean pore size may be at least 10 or 15 µm. The D50 particle size may be not more than 2.5 or 2 µm, or between 1 and 2 µm. The porous interior may also be substantially free of a catalyst coating. The catalyst composition may be present as a single layer, and further layers could be coated from the outlet side of the filter. The catalyst coating may comprise a selective catalytic reduction (SCR) catalyst, or an ammonia slip catalyst. |
