Abstract
With the conflicting goals of achieving both a high purification level and low pressure loss, an attempt was made to control the flow velocity distribution by means of a new honeycomb structure (a compound cell structure having an inside area with a higher cell density and an outside area with a lower cell density). The catalyst utilization efficiency was maximized by optimizing the cell specifications of the inside and outside areas, and their effects under an actual usage environment were compared with conventional substrates, using actual vehicles and engines, and reported in this paper.
