Application of Advanced Three-Way Catalyst Technologies on High Cell Density Ultra Thin-Wall Ceramic Substrates for Future Emission Legislations

The future emission limits for gasoline fuelled passenger cars require more and more efficient exhaust gas aftertreatment devices - the catalytic converter being one essential part of the complex system design. The present paper summarizes the results of several basic research programs putting major emphasis on the application of highly sophisticated three-way catalyst technologies being taylored for the utilization on ultra thin-wall ceramic substrates.

In the first part of the investigation the following effects were examined in detail:

• Different washcoat loadings at constant PGM-loadings
• Different volumes of catalysts for constant amounts of PGM and washcoat
• Similar washcoat technologies at different ratios of WC-loading to precious metal concentration in the washcoat.

The resulting optimized washcoat system was tested in the second part of the investigation on a EU IV calibrated vehicle comparing a state-of-the-art 400 cpsi/6.5 mil ceramic substrate with different types of ultra thin-wall substrates (UTWS) up to 1200 cpsi/2.5 mil. Furthermore, in case of 900 cpsi/2.5 mil two different PGM-loadings were investigated.

The data of the vehicle study confirmed that UTWS in combination with tailor-made coating technologies can offer a big potential to further optimize the converter performance.