Miniature Regeneration Unit

Abstract

A system for controlling the temperature of an exhaust stream from an engine at a location upstream from an exhaust aftertreatment apparatus includes a main exhaust passageway adapted to receive the exhaust stream from the engine. A side branch is in communication with the main exhaust passageway. A regeneration unit is positioned within the side branch for combusting a fuel and heating the exhaust flowing through the main exhaust passageway. An ion sensor is operable to output a signal indicative of the presence of fuel combustion. A controller selectively operates the regeneration unit to increase the exhaust temperature. The controller is operable to control a supply of fuel to the regeneration unit based on the ion sensor signal.

1 . A system for controlling the temperature of an exhaust stream from an engine at a location upstream from an exhaust aftertreatment apparatus, the system comprising:
 a main exhaust passageway adapted to receive the exhaust stream from the engine;   a side branch in communication with the main exhaust passageway;   a regeneration unit positioned within the side branch for combusting a fuel and heating the exhaust flowing through the main exhaust passageway;   an ion sensor operable to output a signal indicative of the presence of fuel combustion; and   a controller for selectively operating the regeneration unit to increase the exhaust temperature, the controller being operable to control a supply of fuel to the regeneration unit based on the ion sensor signal.   
     
     
         2 . The system of  claim 1 , further including supplying a secondary source of oxygen to the regeneration unit. 
     
     
         3 . The system of  claim 2 , wherein the regeneration unit includes a housing defining a primary combustion chamber, the fuel and the secondary source of oxygen being supplied directly to the primary combustion chamber. 
     
     
         4 . The system of  claim 3 , wherein the housing includes a reduced diameter portion at a free distal end. 
     
     
         5 . The system of  claim 3 , wherein the housing includes a first end supported by the side branch and an unsupported second end, the first end including a plurality of apertures extending therethrough for receipt of a portion of the exhaust stream. 
     
     
         6 . The system of  claim 5 , wherein the apertures are defined by displaced flaps of housing material, the flaps being oriented to change the direction of exhaust flow as it enters the housing. 
     
     
         7 . The system of  claim 6 , wherein the flaps are substantially rectangular having three free edges and one edge fixed to the housing. 
     
     
         8 . The system of  claim 7 , wherein the fixed edge is positioned radially outward of an opposite free edge. 
     
     
         9 . The system of  claim 3 , wherein the housing at least partially extends into the main exhaust passageway to cool the housing. 
     
     
         10 . The system of  claim 3 , wherein the regeneration unit includes a housing defining a primary combustion chamber, the fuel being supplied directly to the primary combustion chamber, the secondary source of oxygen being supplied to an external surface of the housing, the housing including apertures to allow a portion of the secondary source of oxygen to enter the primary combustion chamber. 
     
     
         11 . The system of  claim 1 , further including a diverter plate positioned within the main exhaust passageway upstream from the regeneration unit, the diverter plate including an aperture shaped and positioned to direct the exhaust flow toward the regeneration unit. 
     
     
         12 . The system of  claim 11 , wherein the aperture is substantially shaped as the letter D. 
     
     
         13 . The system of  claim 1 , wherein the controller ceases the supply of fuel when the ion sensor signal represents an unexpected extinguishment of combustion. 
     
     
         14 . The system of  claim 1 , wherein the side branch intersects the main exhaust passageway at substantially thirty degrees. 
     
     
         15 . The system of  claim 1 , wherein the side branch has a distal end extending off of the main exhaust passageway that is not in receipt of exhaust. 
     
     
         16 . A system for controlling the temperature of an exhaust stream from an engine at a location upstream from an exhaust aftertreatment apparatus, the system comprising:
 a main exhaust passageway adapted to receive the exhaust stream from the engine;   a blind side branch in communication with the main exhaust passageway;   a regeneration unit positioned within the side branch for combusting a fuel and heating the exhaust flowing through the main exhaust passageway, the regeneration unit including a housing positioned within and spaced apart from a sidewall of the side branch, a nozzle for injecting the fuel into a chamber defined by the housing, and an igniter to initiate combustion of the fuel within the housing; and   a controller for selectively operating the regeneration unit to increase the exhaust temperature.   
     
     
         17 . The system of  claim 16 , further including supplying a secondary source of oxygen to the regeneration unit. 
     
     
         18 . The system of  claim 17 , wherein the housing includes a reduced diameter portion at a free distal end. 
     
     
         19 . The system of  claim 18 , wherein the housing includes a first end supported by the side branch and an unsupported second end, the first end including a plurality of apertures extending therethrough for receipt of a portion of the exhaust stream. 
     
     
         20 . The system of  claim 19 , wherein the apertures are defined by displaced flaps of housing material, the flaps being oriented to change the direction of exhaust flow as it enters the housing. 
     
     
         21 . The system of  claim 20 , wherein the flaps are substantially rectangular having three free edges and one edge fixed to the housing. 
     
     
         22 . The system of  claim 21 , wherein the fixed edge is positioned radially outward of an opposite free edge. 
     
     
         23 . The system of  claim 16 , wherein the housing at least partially extends into the main exhaust passageway to cool the housing. 
     
     
         24 . The system of  claim 16 , further including a secondary air source being supplied to a zone between the housing and the sidewall. 
     
     
         25 . The system of  claim 16 , further including a diverter plate positioned within the main exhaust passageway upstream from the regeneration unit, the diverter plate including an aperture shaped and positioned to direct the exhaust flow toward the regeneration unit. 
     
     
         26 . The system of  claim 25 , wherein the aperture is substantially shaped as the letter D.