Design of High Performance Coated GPF with 2D / 3D Structure Analysis 2019-01-0977
With the strengthening of emission regulations in recent years, it is necessary for gasoline engines to be equipped with Gasoline Particulate Filters (GPF) in order to reduce Particulate Matter (PM) and Particulate Number (PN). There are three functions required for a coated GPF. First is to reduce PM/PN, second is to maintain low pressure drop, and third is to have exhaust gas purification performance. It is important to maximize these three functions with the best balance.
Several types of GPF in various coated states were prepared. Then, the coat state was evaluated by 3D structural analysis with GeoDict and its property characteristics was confirmed by experiment. From these results, the factors that determine the three functions of GPF were investigated with informatics.
Using result of mercury porosimetry analysis, it was found that the median pore diameter of the filter wall in a coated GPF is an important factor for pressure drop and PN filtration efficiency. On the other hand, as a result of analyzing the 3D model created with a CT image, the uniformity of the percolation paths was an important factor for the purification performance. Furthermore, Electron Probe Micro Analyzer (EPMA) was performed to investigate catalyst coating state of the filter wall of coated GPF, and the catalyst coating state and the state of pore formation in EPMA figure was converted into numerical information. The relationship between the factors obtained above and the numerical information from the EPMA images were investigated. It revealed that the important factors of coated GPF can be explained by the numerical information of coated state．In conclusion, it was confirmed that the functions of coated GPF can be controlled and maximized with best balance by adjusting the coating state.