Apparatus and method for gaseous emissions treatment with directed induction heating
An assembly for treating gaseous emissions includes a substrate body having cells for the passages of emissions gas. Lengths of metal wire are located in selected ones of the cells and an induction heating coil is mounted adjacent the substrate body for generating a varying electromagnetic field. In this way the metal wires are heated, resulting in heating of the substrate body and heating of exhaust gas flowing in the cells. The metal wires are distributed non-uniformly through the substrate body to obtain a desired heating pattern.
1. An assembly for treating gaseous emissions comprising a substrate body having a plurality of cells for the passage of emissions gas, respective lengths of metal wire located in each of a first set of the plurality of cells, and an induction heating coil mounted adjacent the substrate body for generating a varying electromagnetic field, thereby inductively to heat the lengths of wire and thereby to heat the substrate body, wherein the wires are distributed non-uniformly through the substrate body to obtain a desired inductance heating pattern at the substrate body, the assembly having a front for entry of gaseous emissions to be treated and a back for exit of treated gaseous emissions, the metal of said metal wires distributed non-uniformly along a longitudinal axis from the front to the back of the substrate body.
2. The assembly as claimed in claim 1 , the locations of the wires selected to obtain generally uniform inductance heating in at least a part of the substrate body.
3. The assembly as claimed in claim 1 , there being a greater concentration of wire per unit volume of the substrate body towards the center of the substrate body than at the perimeter thereof.
4. The assembly as claimed in claim 1 , the substrate body having a relatively higher concentration of wire per unit volume of the substrate body near the front than near the back.
5. The assembly as claimed in claim 1 , at least some of the lengths of wire being wire segments extending only partially along the lengths of the cells.
6. The assembly as claimed in claim 5 , wherein wire segments are located at the front of the substrate body but not at the back of the substrate body, the induction heating coil mounted adjacent the substrate body at the front of the assembly.
7. The assembly as claimed in claim 5 , wherein wire segments in a first subset of the first set of cells are longer than wire segments in a second subset of the first set of cells.
8. The assembly as claimed in claim 7 , wherein the cells of the first subset are closer to the center of the substrate body than the cells of the second subset.
9. The assembly as claimed in claim 5 , the cells of the first set each containing a plurality of discrete wire lengths distributed along the length of the respective cell.
10. The assembly as claimed in claim 1 , the substrate body having a front for entry of gaseous emissions to be treated and a back for exit of treated gaseous emissions, at least some of the wires projecting from the front of the substrate body.
11. The assembly as claimed in claim 1 , the metallic composition of one wire being different from the metallic composition of at least one other wire.
12. The assembly as claimed in claim 1 , the concentration of wire per unit volume of the substrate body selected to obtain a desired level of inductance heating near the center of the substrate body.
13. The assembly as claimed in claim 1 , the substrate body made of a ceramic honeycomb material.
14. The assembly as claimed in claim 1 , the metal being a ferromagnetic metal.
15. The assembly as claimed in claim 1 , the wires having one of a hollow and an open cross-section configuration.
16. A method of treating gaseous emissions using an assembly having an induction heating coil mounted adjacent a substrate body, the substrate body having a plurality of cells for the passages of emissions gas and respective lengths of metal wire located in each of a first set of the plurality of cells, the assembly having a front for entry of gaseous emissions to be treated and a back for exit of treated gaseous emissions, the metal of said metal wires distributed non-uniformly along a longitudinal axis from the front to the back of the substrate body, the method comprising generating a varying electromagnetic field at the coil thereby to cause induction heating of the lengths of wire with heat from the heated lengths of wire being transferred to the substrate body and the gaseous emissions passing along the cells, the location of the non-uniform distribution of wires being such as to obtain an amount of heating of the substrate body that varies along a longitudinal axis from the front to the back of the substrate body.
17. The process as claimed in claim 16 , further comprising generating the varying electromagnetic field when an engine which is the source of the emission gases is operating and when the substrate body is below a predetermined threshold temperature.
18. The process as claimed in claim 16 , further comprising generating the varying electromagnetic field for an engine which is to be the source of the emission gases before start-up of the engine.
19. The process as claimed in claim 16 , further comprising inductively preheating gaseous emissions before the gaseous emissions enter the substrate body.
20. The process as claimed in claim 16 , further comprising the heat from the heated lengths of wire also being transferred to a catalyst coating the surface of the cells, the heated catalyst operable to accelerate pollution-reducing reactions of components in the gaseous emissions.