Exhaust aftertreatment system with spiral mixer

An exhaust aftertreatment system comprising an exhaust conduit carrying exhaust to an aftertreatment element treating said exhaust, an injector injecting chemical species mixing with said exhaust prior to reaching said aftertreatment element, a mixer in said exhaust system upstream of said aftertreatment element and mixing said chemical species and said exhaust, wherein said mixer is a spiral chamber configured to facilitate long mixing distance and time without increasing axial length and thus providing a compact mixer arrangement;

• wherein said first exhaust flow port is an inlet exhaust flow port, and said second exhaust flow port is an outlet exhaust flow port, and wherein exhaust flows from said inner reach of said spiral through said outlet exhaust flow port along an axial flow direction along said central axis;
• and
• an outlet exhaust pipe extending axially from said spiral chamber at said outlet exhaust flow port, said outlet exhaust pipe having an outer portion extending axially externally of said spiral chamber and conducting exhaust axially therethrough for transmission to said aftertreatment element, said outlet exhaust pipe having an inner portion extending axially internally of said spiral chamber, said inner portion of said outlet exhaust pipe being perforated and receiving exhaust through such perforations from said spiral chamber at said inner reach thereof.

An exhaust aftertreatment system comprising an exhaust conduit carrying exhaust to an aftertreatment element treating said exhaust, an injector injecting chemical species mixing with said exhaust prior to reaching said aftertreatment element, a mixer in said exhaust system upstream of said aftertreatment element and mixing said chemical species and said exhaust, wherein said mixer is a spiral chamber configured to facilitate long mixing distance and time without increasing axial length and thus providing a compact mixer arrangement;

• wherein said spiral chamber has first and second exhaust flow ports for exhaust flow therethrough, wherein one of said first and second exhaust flow ports is an inlet exhaust flow port, and comprising an inlet exhaust pipe extending from said spiral chamber at said inlet exhaust flow port, and wherein said injector is in said inlet exhaust pipe and injects said chemical species into said exhaust prior to and upstream of said spiral chamber.

An exhaust aftertreatment system comprising an exhaust conduit carrying exhaust to an aftertreatment element treating said exhaust, an injector injecting chemical species mixing with said exhaust prior to reaching said aftertreatment element, a mixer in said exhaust system upstream of said aftertreatment element and mixing said chemical species and said exhaust, wherein said mixer is a spiral chamber configured to facilitate long mixing distance and time without increasing axial length and thus providing a compact mixer arrangement;

• wherein said spiral chamber has an inner scroll wall defining a spiral exhaust flow passage, said spiral chamber having first and second exhaust flow ports for exhaust flow therethrough, said spiral chamber having first and second axially spaced chamber walls having said scroll wall disposed axially therebetween;
• and
• wherein said second chamber wall is perforated and provides said second exhaust flow port for exhaust flow therethrough.