Combination muffler and catalytic converter

A combination muffler and catalytic converter assembly comprising an outer housing having inlet and outlet tubes therein for receiving and exhausting exhaust gases from an internal combustion engine to which the assembly is adapted to be attached;

• an axial flow monolithic catalytic converter element positioned within said housing and radially spaced from the walls thereof in the path of said exhaust gases;
• aspirator means including a plurality of openings and a venturi portion in said inlet tube for sucking secondary air through said plurality of openings and into an exhaust gas stream passing through said venturi portion of said inlet tube;
• a perforated distributor plate having a plurality of spaced openings defining an open area equal to 20 - 40% of the open face inlet area of the catalytic converter element, said distributor plate being positioned in said housing intermediate said aspirator means and said catalytic converter element, said perforated distributor plate containing at least 5 openings per square inch and being spaced upstream from the inlet end of said monolithic catalytic converter element by at least about 5.5 times the diameter of the openings in the distributor plate, the openings in said perforated distributor plate defining a pattern whose outer periphery generally corresponds to the outer periphery of the open inlet face area of the catalytic converter element, and turbulence inducing means positioned between said distributor plate and the inlet end of said inlet tube, said turbulence inducing means including a stationary vane member in the exhaust inlet upstream of the venturi for swirling the exhaust gases and a deflector member downstream of the venturi for reversing their flow.