Impact of Ultra Thinwall Catalyst Substrates for TIER2 Emission Standards

The impact of ultra thinwall catalysts on TIER2 emission performance, packaging and total system cost was evaluated. The primary focus was to compare ultra-thinwall and thinwall cell configurations (400/3, 400/4, 600/2, 600/3, 600/3 hex, 900/2, and 1200/2) with a baseline 600/4 at constant substrate volume, washcoat and PGM loading. Other areas investigated included the evaluation of decreasing catalyst volume while maintaining constant or increased mass transfer capabilities while holding washcoat and PGM loadings constant. The emissions impact of varying washcoat and PGM loading was measured on specific substrates, including a comparison of square to hex cell.

Backpressure for each configuration was calculated with the Corning substrate pressure drop modeling tool. Converters were rapid aged on dynamometers reflecting approximately a 50,000 mile aged performance. Emission testing was completed using the FTP test cycle. Both bag and modal emissions were measured along with converter temperatures. A rapid cooling system was utilized which allowed 3 complete FTP tests and a converter change within an 8-hour shift. An 18 cycle prep and cool down was completed prior to the first FTP of the day to ensure that all 3 FTP were run consistently.