Metal Foam Substrate for DOC and DPF Applications

A new metal foam material for diesel particulate filtration, trademarked as INCOFOAM® HighTemp, was recently presented. Extensive tests showed the potential of achieving filtration efficiencies of the order of 85% or more at low pressure drop using a radial flow design concept with graded foam porosity. By applying a catalytic washcoat, the foam exhibits enhanced gas mixing and thus higher conversion efficiencies at high space velocities. In addition, due to an excellent soot-catalyst contact, the washcoated foam exhibited high catalytic regeneration rates. The present paper focuses on a novel “cross-flow” design concept for a better filtration/pressure drop trade-off as well as application of the foam as an oxidation catalyst substrate. The experimental testing starts from small-scale reactors and proceeds to real exhaust testing on the engine bench as well as vehicle tests on the chassis dynamometer and on-road testing. It is shown that the foam structure exhibits excellent mass-transport properties offering possibilities for precious metal and catalyst volume savings for oxidation catalyst applications.