Abstract: There is disclosed a catalytic converter substrate formed of two smooth foil strips and one corrugated foil strip arranged and folded together so that alternate folds of each of the smooth foil strips have spaced sides and juxtaposed abutting sides and interleave with those of the other smooth foil strip and so that all of the folds of the corrugated foil strip have spaced sides that sandwich the folds with juxtaposed abutting sides of both the smooth foil strips so as to define passages therebetween and whereby all the strips are adapted to be retained together against telescoping by engaging retaining means at the opposite ends of all of their folds.

Abstract: In a catalytic converter, an air tube is permanently fixed and sealed at an open end thereof between two flanges on one side of a clamshell type housing enclosing reducing and oxidizing catalyst means. The tube extends between the catalyst means and has a closed end slidably mounted between flanges of the housing on the opposite side thereof internal of where these flanges are joined. The tube which has holes for delivering air into the passing exhaust gases prior to reaching the oxidizing catalyst is thus firmly supported by the housing while relative expansion with heat is permitted therebetween and without interrupting the sealed integrity of the housing flanges at the closed end of the tube.

Abstract: In a catalytic converter, a short closed-end air tube which extends across the path of the exhaust gases ahead of an oxidizing catalyst is provided with three linear circumferentially-spaced rows of holes with the holes in one of the rows facing upstream into the exhaust gases while the holes in the other two rows face in opposite directions transverse to the exhaust gas flow. The holes in each of the rows are equally spaced along the length of the tube and decrease in size toward the closed end so as to deliver substantially equal amounts of air. In addition, the holes in the three rows are sized in relation to each other so that the two rows of transversely directed holes deliver substantially equal and cooperatively greater amounts of air than the row of holes facing into the exhaust gases.

Abstract: A catalytic converter comprises an annular monolithic catalyst element in a cylindrical can having one closed axial end and a central inlet opening and peripheral outlet openings at the other axial end. The catalyst element has an inner cylindrical surface defining a central axial opening therethrough aligned with the inlet opening. A conduit extends from the inlet opening through the central axial opening of the catalyst element to conduct exhaust gases from the inlet opening to the closed end of the casing for return flow through the catalyst element to the outlet openings. The portion of the exhaust conduit within the central opening of the catalyst element is cylindrical and is spaced slightly away from the inner surface of the catalyst element to define an annular space therebetween, the annular space being so thin as to force exhaust gases leaking therethrough into contact with the inner surface of the catalyst element.