Electrically heated diesel oxidation catalyst

Abstract

An exhaust gas aftertreatment system ( 10 ) for a vehicle having an engine ( 14 ) includes a fluid passageway ( 20 ) extending from the engine to an ambient ( 18 ) for fluidly communicating exhaust gas (F). A diesel particulate filter ( 30 ) is disposed on the fluid passageway downstream of the engine ( 14 ). Disposed downstream of the engine ( 14 ) and upstream of the diesel particulate filter ( 30 ) is an electric diesel oxidation catalyst ( 24 ) having a substrate ( 34 ). A first electrode ( 40 ) and a second electrode ( 46 ) are attached to the electric diesel oxidation catalyst ( 24 ). The first electrode ( 40 ) selectively delivers current through the substrate ( 34 ) to the second electrode ( 46 ) to generate heat at the substrate ( 34 ).

1 ) An exhaust gas aftertreatment system for a vehicle having an engine, the aftertreatment system comprising:
 a fluid passageway extending from the engine to an ambient for fluidly communicating exhaust gas;   a diesel particulate filter disposed on the fluid passageway downstream of the engine;   an electric diesel oxidation catalyst disposed downstream of the engine and upstream of the diesel particulate filter on the fluid passageway, the electric diesel oxidation catalyst having a substrate; and   a first electrode and a second electrode attached to the electric diesel oxidation catalyst, the first electrode for selectively delivering current through the substrate to the second electrode to generate heat at the substrate.   
     
     
         2 ) The aftertreatment system of  claim 1  further comprising a first transmission wire electrically connected to the engine for providing electric current to the first electrode. 
     
     
         3 ) The aftertreatment system of  claim 2  further comprising a second transmission wire electrically connected to the engine for transmitting electric current from the second electrode to the engine. 
     
     
         4 ) The aftertreatment system of  claim 1  wherein the electric diesel oxidation catalyst includes a housing enclosing the substrate. 
     
     
         5 ) The aftertreatment system of  claim 4  further comprising an isolator disposed about the first electrode to prevent the contact of the first electrode with the housing. 
     
     
         6 ) The aftertreatment system of  claim 1  wherein the substrate permits the flow of exhaust gas therethrough. 
     
     
         7 ) The aftertreatment system of  claim 1  wherein the first electrode extends into the electric diesel oxidation catalyst generally the radius of the electric diesel oxidation catalyst. 
     
     
         8 ) The aftertreatment system of  claim 1  wherein the first electrode and the second electrode are spaced from each other and separated by the substrate. 
     
     
         9 ) The aftertreatment system of  claim 1  further comprising a diesel oxidation catalyst disposed on the fluid passageway downstream of the electric diesel oxidation catalyst and upstream of the diesel particulate filter. 
     
     
         10 ) A method of regenerating an exhaust aftertreatment system of an engine having a diesel particulate filter, the method comprising:
 providing a fluid passageway from the engine to an ambient;   providing a substrate upstream of the diesel particulate filter on the fluid passageway;   heating the substrate electrically;   heating exhaust gas flowing through the heated substrate; and   delivering the heated exhaust gas to the diesel particulate filter to initiate regeneration.   
     
     
         11 ) The method of  claim 11  further comprising the step of contacting a first electrode with the substrate. 
     
     
         12 ) The method of  claim 12  further comprising the step of connecting the first electrode to the engine with a first transmission wire. 
     
     
         13 ) The method of  claim 12  further comprising the step of contacting a second electrode with a housing that substantially encloses the substrate. 
     
     
         14 ) The method of  claim 13  further comprising the step of connecting the second electrode to the engine with a second transmission wire. 
     
     
         15 ) The method of  claim 14  further comprising the step of providing electric current from the engine to the first electrode, through the substrate, to the second electrode, and back to the engine. 
     
     
         16 ) An electric diesel oxidation catalyst for an exhaust aftertreatment system of an engine, the electric diesel oxidation catalyst comprising:
 a housing substantially enclosing a substrate, the housing having an inlet and an outlet configured for permitting a flow of exhaust gas through the housing;   a first electrode extending through the housing configured for providing an electric current to the substrate; and   a second electrode extending from the housing configured for receiving the electric current from the substrate.   
     
     
         17 ) The electric diesel oxidation catalyst of  claim 16  wherein the first electrode contacts the substrate generally at the cross-sectional center of the substrate. 
     
     
         18 ) The electric diesel oxidation catalyst of  claim 16  wherein the first electrode and the second electrode are spaced from each other and separated by the substrate. 
     
     
         19 ) The electric diesel oxidation catalyst of  claim 16  further comprising an isolator sleeve disposed around the first electrode. 
     
     
         20 ) The electric diesel oxidation catalyst of  claim 16  wherein the housing is generally cylindrical.