Development of GPF Using Micro-CT Measurement and Numerical Analytical Technique

Gasoline particulate filters (GPFs) have recently been employed in gasoline fueled vehicles to trap particulate matter from exhaust fumes. The severe emission regulations which will be imposed in the near future will require GPFs to control the particulate number (PN) and exhaust gas (CO, HC, NO_x) emissions and have low back pressure. To satisfy all these requirements, a unique catalytic design has been developed in which two different catalyst layers are applied within the GPF wall. The first catalytic layer is relatively coarse and contributes to the low back pressure and high gas conversion performance; the second is relatively dense and contributes to high PN filtration efficiency. The pore size, pore volume, and penetrating pore number were analyzed by numerical analysis followed by micro computed tomography (micro-CT). From the precise micro-CT measurement and numerical analysis of the penetrating pores, correlations were observed between the small penetration pore structure and PN filtration efficiency, and between the large penetration pore structure and back pressure.