Soot trapping on GPF, TWC Membrane fabrication on GPF, and soot trapping on TWC membrane have been studied using computer numerical simulation. The results of pressure drop, filtration efficiency, and morphology visualization satisfied the experimental results. The simulation could clarify the trapping phenomena up to 3D-nanoscale resolution, which overcame an experimental limitation. Visualization revealed the particles first trapped on the substrate generating a dendrite structure at the constricted area. Then, it expanded by accumulating flying particles until the bridge structure was completed, which is the same point of 100% filtration efficiency that proved the hypothesis from the experiment.

A membrane filter was coated on conventional filter made of SiC. The first and second layers consisted of aluminaparticles with diameter of 0.5 and 1.5 micrometer, respectively; because small particles have higher filtration efficiency to prevent soot penetration into the membrane layer while large particles with a higher permeability can achieve lower pressure drop. Nanoscale silverpalladium particles were dispersedly deposited on the surface of the alumina particles layer as a top layer. The novel membrane filter demonstrated lower pressure drop while keeping high trapping efficiency during the soot trapping and presented lower soot oxidation temperature compared to the conventional filter.

A granular substrate used as a support for a three-way catalyzed (TWC) solid-particle membrane filter was investigated through numerical simulation. The proposed support could reduce the amount of required catalyst material by 39% and lower the pressure drop by 33%, compared to a conventional filter, while achieving almost 100% soot-filtration. Moreover, TWC porous particles, which are designed to introduce a fluid flow into their interconnected pore network, further decrease the pressure drop. However, a trade-off exists between the amount of the introduced fluid flow and the specific surface area.

A membrane filter was fabricated using gas dispersant micro-sized Three-way Catalyst (TWC) particles on the conventional filter substrate. The porosity of the cross-sectional area of the TWC-membrane was measured through electron microscopy image processing technique. In the membrane manufacturing process, a parametric study was conducted by comparing three mean particle sizes under three superficial velocities. According to high resolution electron micrographs, the cross-sectional view of a single TWC-particle was revealed as a homogeneously agglomerated particle. The porosity of the cross-sectional area of the membrane was measured as approximately 64.4% with a slight difference about 3% depending on varying mean particle sizes and superficial velocities.