Coaxial Inlet And Outlet Exhaust Treatment Device

A burner for an exhaust gas treatment system to treat an exhaust flow from an engine, the burner comprising:

• a cylindrical inner housing extending along a central longitudinal axis and including a closed upstream end, an open downstream end and a reduced diameter necked portion between the upstream and downstream ends, the inner housing surrounding a primary combustion zone and a secondary combustion zone position on either side of the necked portion, the inner housing including a plurality of apertures within the necked portion for receipt of a first portion of the exhaust flow;
• an outer housing surrounding the inner housing to define a bypass flow path between the inner and outer housings to bypass a second portion of the exhaust flow around the inner housing outside of the primary and secondary combustion zones, the outer housing including an exhaust inlet coaxially aligned with an exhaust outlet along the central longitudinal axis;
• a first support fixing the upstream end of the inner housing to the outer housing and providing fluid communication between the primary combustion zone and a location outside of the outer housing;
• a second support fixing the upstream end of inner housing to the outer housing and providing fluid communication between the primary combustion zone and another location outside of the outer housing;
• a third support fixing the downstream end of the inner housing to the outer housing, the third support cooperating with the inner and outer housings to at least partially define a portion of the bypass flow path;
• and
• an injector mounted to the first support at a position offset from the central longitudinal axis, the injector being operable to inject fuel into the primary combustion chamber toward the central longitudinal axis.