Combination muffler and catalytic converter having low backpressure

摘要

Combination muffler and catalytic converter utilizes an axial flow monolithic catalytic element to treat exhaust gases from an internal combustion engine and partially reduce their sound. The device incorporates a venturi in the exhaust gas inlet path to add secondary air. The efficiency of the venturi is quite high since backpressures introduced downstream of the venturi are kept low by providing an extremely long outlet cone for the venturi which reverses the flow direction while preventing wall separation and turbulence. Sound attenuation is provided upstream of the venturi where the backpressures produced have minimum effect in reducing venturi efficiency.