Model-based analysis of TWC-coated filters performance aspects
Grigorios Koltsakis, Aristotle University Thessaloniki
The wall flow filter technology is already an important element in gasoline engine emissions control. In addition to the filtration functions, the active catalytic coating can contribute to the reduction of gaseous emissions slipping from the upstream TWC. The substrate and coating technology require precise engineering to achieve the emissions target without sacrificing fuel penalty associated with excessive backpressure and active regeneration. The present contribution addresses the main challenges in developing predictive models supporting the design and control of coated GPFs, including filtration and pressure drop, soot oxidation and effects of ash. The effect of soot and ash on TWC functions as well as the O2 competition between soot and the reactive surface is studied by analyzing the coupled transport-reaction processes at wall-scale. The modeling study is supported by measurements with filters of different cell structures and wall properties performed under steady-state and transient modes. A discussion on modeling approaches towards optimizing pore size distribution is included.