Dual-monolith catalytic converter with secondary air injection

摘要

A dual-monolith catalytic converter having upstream and downstream located substrates and a configuration such that the exhaust gas flow is non-uniformly distributed across the upstream frontal areas of each of the substrates and concentrated centrally of such frontal areas. The converter further has a chamber located between said substrates. An air distribution tube having an open end adapted to be connected to the pulsed air supply extends through and across the chamber substantially normal to the exhaust gas flowing between the substrates and terminates with a closed end. The tube within the chamber has a plurality of holes which are sized and spaced along the tube to non-uniformly distribute the pulsed air supply throughout the chamber in a manner to provide a resultant air flow distribution conforming with the non-uniform distribution of exhaust gas. Flow dividers are spaced along the tube and extend substantially parallel to the flow of exhaust gas between the substrates in a manner to partition the chamber into a plurality of discrete channels each open to selected ones of the holes to receive one portion only of the non-uniform distribution of the pulsed air supply and one portion only of the non-uniformly distributed exhaust gas whereby the non-uniform air flow distribution is maintained between the channels while the exhaust gas is flowing between the substrates to prevent the exhaust gas from entering the downstream substrate with an improper mix of pulsed air so that the conversion efficiency of the downstream substrate is maximized.