Electrically heated mixer assembly for an exhaust aftertreatment system

A method for mixing, in a mixing tube of an exhaust aftertreatment system, a reductant with an exhaust gas from an internal combustion engine, the method comprising:

• heating, by an electrically heated heating element parallel to and separated from an impingement surface of a mixer;
• accepting the exhaust gas at a first aftertreatment component external to the mixing tube and in fluid communication therewith and with an exhaust conduit;
• injecting, by a reductant injector positioned in proximity to the impingement surface, the reductant causing the reductant to directly impinge on the impingement surface, vaporize, and mix with the exhaust gas forming a vaporized reductant and exhaust gas mixtures that flows along a flow path defined by the mixing tube;
• heating and mixing, by the electrically heated heating element, the vaporized reductant and exhaust gas mixture before the vaporized reductant and exhaust gas enters a gas phase mixer within the mixing tube;
• and
• accepting the heated exhaust mixture at a second aftertreatment component external to the mixing tube and in fluid communication therewith and with an exhaust stack.

A selective catalytic reduction (SCR) aftertreatment system for treating exhaust gas from an internal combustion engine, the SCR aftertreatment system comprising:

• a mixing tube including an inlet end, an outlet end, and an opening;
• a diesel exhaust fuel (DEF) injector, communicably coupled with the opening, that injects DEF into the mixing tube;
• and
• a mixer assembly including:
• an electrically heated heating element disposed within the mixing tube and in proximity to the DEF injector;
• a mixer, disposed within the mixing tube parallel to and removed from the electrically heated heating element and the DEF injector, including an impingement surface;
• and
• an SCR catalyst positioned downstream of the electrically heated heating element and in fluid communication with and external to the mixing tube,
• wherein the impingement surface is located at a position that enables the electrically heated heating element to heat the impingement surface and that enables direct impingement of the reductant, after being injected, on the impingement surface to vaporize and mix the reductant with the exhaust gas forming a vaporized reductant and exhaust gas mixture that flows along a flow path of the mixing tube, and
• wherein the electrically heated heating element is positioned within the flow path to heat and further mix the reductant and exhaust gas mixture before the reductant and exhaust gas mixture enters the SCR catalyst.