Patent Publication Number: US-2015064079-A1

Title: Catalyst substrate module for exhaust aftertreatment system

Description:
TECHNICAL FIELD 
     The present disclosure relates to exhaust aftertreatment systems. More particularly, the present disclosure relates to a catalyst substrate for a catalytic converter and can be applied to filters of an exhaust aftertreatment system. 
     BACKGROUND 
     Exhaust gases from internal combustion engines may contain substances, such as nitrogen oxides (NOx), hydrocarbons, carbon monoxide, particulate matter, and/or the like. Some exhaust gas substances may be unfavorable to the environment. Over the years, efforts have been made within the internal combustion engine industry to reduce unfavorable substances that may be present in exhaust gases before the gases are discharged into the atmosphere. This has been accomplished by improvement of the combustion process or/and by treatment of the exhaust gases and particulate matter. The exhaust gases can be treated by appropriate oxidation catalyst and/or by selective catalytic reduction (SCR) whereas particulate matter can be treated using oxidation catalyst and/or filter. 
     Exhaust treatment system may include a planar substrate that encompasses a significant portion of the internal flow conduit and as such the substrate is subject to significant pressure generated by the exhaust flow. In some cases, the substrate is subject to high vibration. The pressure or high vibration can slide the substrate from mantel or tear the substrate from mantel and slide the substrate out. United States Publication No. 2009/065296 illustrates a fixing device which includes a muffler and a catalyst mantle. The muffler has at least one clapboard on which the catalyst mantle is integrated. At least one block is configured to prevent the substrate from sliding to the exhaust terminal and a stopper is formed on the clapboard or an inner wall of the muffler to prevent the substrate sliding to the admission terminal The fixing device improves the fixing capacity of the substrate for arranging the catalyst mantle in the muffler. However, where multiple catalytic converters are included in a housing or module, especially in exhaust systems associated with large power systems, removal and replacement of an individual catalytic converter may be complicated. 
     SUMMARY OF THE INVENTION 
     The present disclosure relates to a catalyst substrate module in an exhaust aftertreatment system. 
     In accordance with the present disclosure, the catalyst substrate module includes an outer containment wall, an inner containment wall, a first bar, a second bar, a first substrate element, a second substrate element, and a center member. The outer containment wall defines a first end, a second end, an inner face, and a centerline. The inner containment wall defines a first end, a second end, an inner face, an outer face and a centerline. The centerline of the inner containment wall is substantially aligned with the centerline of the outer containment wall. The first bar includes a first bar end, a second bar end, and a center bar portion. Each of the first bar end and second bar end of the first bar is connected to a portion of the inner face of the outer containment wall, wherein the center bar portion of the first bar substantially aligns with the centerline of the outer containment wall. The first ends of the inner containment wall and outer containment wall are structured and arranged to engage with the first bar. The second bar includes a first bar end, a second bar end, and a center bar portion. Each of the first bar end and the second bar end of the second bar is connected to a portion of the inner face of the outer containment wall, wherein the center bar portion of the second bar substantially aligns with the center line of the outer containment wall. The second ends of the inner containment wall and outer containment wall are structured and arranged to engage with the second bar. The first substrate element is enclosed within the inner face of the inner containment wall, and the first bar and second bar on each end of the inner containment wall. The second substrate element is positioned within a space defined by the outer face of the inner containment wall and the inner face of the outer containment wall. The second substrate element is enclosed by the first bar and the second bar, on each end of the inner containment wall and outer containment wall. Further, the center member extends along the centerline of the inner containment wall. The center member includes a first end and a second end. The first end of the center member is attached to the center bar portion of the first bar and the second end of the center member is attached to the center bar portion of the second bar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic view of an engine with an exhaust aftertreatment system, in accordance with the concepts of the present disclosure; 
         FIG. 2  is a perspective view of a catalyst substrate module of the exhaust aftertreatment system of  FIG. 1 , with the substrate elements removed to illustrate the catalyst substrate module showing the containment walls and bars, in accordance with the concepts of the present disclosure; 
         FIG. 3  is a perspective view of the catalyst substrate module of  FIG. 2 , to illustrate the catalyst substrate module showing the containment walls and bars, in accordance with the concepts of the present disclosure; 
         FIG. 4  is a perspective view of the catalyst substrate module of  FIG. 2 , with substrate elements positioned in the catalyst substrate module, in accordance with the concepts of the present disclosure; and 
         FIG. 5  is a sectional view of the catalyst substrate module along section line  5 - 5  of  FIG. 4 , such that a center member and the substrate elements are visible, in accordance with the concepts of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , there is shown an engine  100  with an exhaust aftertreatment system  102 . The engine  100  may include features not shown, such as fuel systems, air systems, cooling systems, electrical systems, lubrication systems, and any other system each of which may be relevant to internal combustion engine technology and known to those having ordinary skill in the art. The engine  100  may be a type of combustion engine (internal combustion, turbine, gas, diesel, gaseous fuel, natural gas, propane, and/or the like), may be of any size, with a plurality of cylinders, and in multiple configurations (“V,” in-line, radial, and/or the like). The engine  100  may be used to power a machine or other device, which includes: locomotive applications, on-highway trucks or vehicles, off-highway trucks or machines, earth moving equipment, generators, aerospace applications, marine applications, pumps, stationary equipment, and/or other engine-powered applications known to those having ordinary skill in the art. The engine  100  may include a plurality of cylinders (not shown), where combustion of fuel and charge air occurs. The combustion in the cylinder of the engine  100  results in the formation of exhaust gases. The exhaust gases from the cylinder may be navigated toward the exhaust aftertreatment system  102 . 
     The exhaust aftertreatment system  102  may include a first exhaust conduit  104 , a diesel oxidation catalyst  106 , a diesel particulate filter  108 , a second exhaust conduit  110 , a reductant supply system  112 , and a catalytic converter  114 . The first exhaust conduit  104  may define an exhaust flow path and may be disposed along a flow direction of the exhaust gases. The first exhaust conduit  104  includes a first inlet  116  and a first outlet  118 . The first inlet  116  of the first exhaust conduit  104  may be in fluid communication with one of the plurality of cylinders, such that, the exhaust gases that exit the cylinders are directed into the first exhaust conduit  104 . The first outlet  118  may be in fluid communication with the diesel oxidation catalyst  106 , which in turn, is in fluid communication with the diesel particulate filter  108 . The diesel particulate filter  108  may be positioned downstream of the diesel oxidation catalyst  106  or downstream of the catalytic converter  114 . Each of the diesel oxidation catalyst  106  and the catalytic converter  114 , houses a catalyst substrate module  120 , such that the exhaust gases that flow through the second exhaust conduit  110  pass through the catalyst substrate module  120 . 
     The diesel particulate filter  108  may be in fluid communication with the catalytic converter  114 , via the second exhaust conduit  110 . The second exhaust conduit  110  may be in fluid communication with the reductant supply system  112 . The reductant supply system  112  includes a reductant source  122 , which is fluidly connected to a reductant injector  124 , via a supply line  126 . The reductant source  122  may be a hydrocarbon source. The reductant injector  124  is provided for injection into the second exhaust conduit  110 . Further, the second exhaust conduit  110  is positioned upstream of the catalytic converter  114  and is in fluid communication with the catalytic converter  114 . 
     Referring to  FIG. 2 , there is shown a first side of the catalyst substrate module  120  and in  FIG. 3 , the opposite side or a second side of the catalyst substrate module  120  is illustrated. The catalyst substrate module  120  includes an outer containment wall  200 , an inner containment wall  202 , at least one first bar  204 , at least one second bar  206 , a first substrate element (shown as  400  in  FIG. 4 ), a second substrate element (shown as  402  in  FIG. 4 ), and a center member  208  extending along axial centerline X-X. The outer containment wall  200  includes a first end  210  and a second end  212 . The first end  210  and the second end  212  includes the centerline X-X, which extends between the first end  210  and the second end  212  of the outer containment wall  200 . The first end  210  and the second end  212  define an inner face  214 . Similarly, the inner containment wall  202  includes a first end  216  and a second end  218 . The first end  216  and the second end  218  includes a centerline X-X, which extends between the first end  216  and the second end  218  of the inner containment wall  202 . The first end  216  and the second end  218  define an inner face  220  and an outer face  222 . Further, the outer containment wall  200  and the inner containment wall  202  are concentrically coupled such that the first end  210  of the outer containment wall  200 , and the first end  216  of the inner containment wall  202 , is co-planar. Similarly, the second end  212  of the outer containment wall  200  and the second end  218  of the inner containment wall  202  may be substantially co-planar. 
     Further, the outer containment wall  200  and the inner containment wall  202  are reinforced together by the plurality of first bars  204  and the plurality of second bars  206 . The plurality of first bars  204  and the plurality of second bars  206  span the diameter of the outer containment wall  200 . The plurality of first bars  204  and the plurality of second bars  206  act as support members for the first substrate element (shown as  400  in  FIG. 4 ) and the second substrate element (shown as  402  in  FIG. 4 ). Each of the plurality of first bar  204  is attached on the first ends  210  and  216  of the outer containment wall  200  and the inner containment wall  202 . The first bar  204  includes a first bar end  224 , a second bar end  226 , and a center bar portion  228 . The first bar  204  is structured such that the first bar end  224  and the second bar end  226 , are attached to the inner face  214 , at the first end  210  of the outer containment wall  200 . The center bar portion  228  of the first bar  204  is structured to align with the centerline X-X of the outer containment wall  200 . Similarly, the second bar  206  is attached on the second sides of the outer containment wall  200  and the inner containment wall  202 . The second bar  206  includes a first bar end  230 , a second bar end  232 , and a center bar portion  234 . The second bar  206  is structured such that the first bar end  230  and the second bar end  232  are attached to the inner face  214 , at the second end  212  of the outer containment wall  200 . The center bar portion  234  of the first bar  204  is structured to align with the center line of the outer containment wall  200 . 
     The center member  208  extends along the centerline X-X of the inner containment wall  202 . The center member  208  with both ends is illustrated in  FIG. 5 . 
     In an embodiment, the catalyst substrate module  120  also includes a first ring  236  and a second ring  238 . The first ring  236  is flushed at the inner face  214  of the first end  210  of the outer containment wall  200 . Similarly, the second ring  238  is flushed at the inner face  214  of the second end  212  of the outer containment wall  200 . 
     Referring to  FIG. 4 , there is shown the catalyst substrate module  120  depicted with a section line  5 - 5 . The catalyst substrate module  120  is shown enclosing the first substrate element  400  and the second substrate element  402 . The first substrate element  400  and the second substrate element  402  are equal in weight. The first substrate element  400  and the second substrate element  402  may include a metallic core and a porous ceramic coating on the metallic core. The first substrate element  400  and the second substrate element  402  may also include a washcoat, which substantially covers the ceramic coating and includes a catalyst material configured to react with the constituents within an exhaust flow of an exhaust-producing engine  100 . Each of the first substrate element  400  and the second substrate element  402  may have any of a number variety of geometrical shapes. For example, the first substrate element  400  and the second substrate element  402  may have a cross-sectional shape, such as square, elliptical/oval/racetrack-shaped, rectangular, polygonal, or the like. The first substrate element  400  and the second substrate element  402  may also have a honeycomb configuration. The first substrate element  400  and the second substrate element  402  may define a plurality of elongated, hollow cells through which the exhaust gases may flow. The elongated cells may have a square cross-section, rectangular cross-section, hexagonal cross-section, or any suitable shape. 
     The first substrate element  400  has a circular cross-section and is structured to allow the exhaust gases to flow. The first substrate element  400  is enclosed within the inner face  220  of the inner containment wall  202 , and extends along a length of the inner containment wall  202 . In addition, the first substrate element  400  is enclosed by the first bar  204  and the second bar  206  and is between the first end  216  and the second end  218  of the inner containment wall  202 . 
     The second substrate element  402  is structured to have a cross section of a concentric ring. The second substrate element  402  is positioned within the space defined by the outer face  222  of the inner containment wall  202  and the inner face  214  of the outer containment wall  200  and on each end of the inner containment wall  202  and outer containment wall  200  by the bars  204  the second bars  206 . 
     Referring to  FIG. 5 , there is shown a sectional view of the catalyst substrate module  120 . The cut section illustrates the outer containment wall  200 , the inner containment wall  202 , the first substrate element  400 , the second substrate element  402 , and the center member  208 . The center member  208  includes a first end  500  and a second end  502 . The first end  500  of the center member  208  is attached to the center bar portion  228  of the first bar  204 . Similarly, the second end  502  of the center member  208  is attached to the center bar portion  234  of the second bar  206 . 
     INDUSTRIAL APPLICABILITY 
     In operation, an air/fuel mixture is combusted in the cylinders of the engine  100  and exhaust gases are produced. The exhaust gases are directed to the exhaust aftertreatment system  102  for treatment before release into the atmosphere. For this purpose, the exhaust gases are directed through the diesel oxidation catalyst  106  and the catalytic converter  114  for conversion of toxic pollutants to less toxic pollutants by catalysis of a redox or oxidation reaction. Both, the diesel oxidation catalyst  106  and the catalytic converter  114  are, equipped with the catalyst substrate module  120 . The disclosed catalyst substrate module  120  includes the outer containment wall  200  and the inner containment wall  202 , which house the first substrate element  400  and the second substrate element  402 . The outer containment wall  200  and the inner containment wall  202  are reinforced with the first bar  204  and the second bar  206 , on each end of the catalyst substrate module  120 . Concentric structural arrangement of the first substrate element  400  and the second substrate element  402  contribute to the minimization of movement and weight of the first substrate element  400  and the second substrate element  402 . Addition of the center member  208 , along with the plurality of first bars  204  and the plurality of second bars  206 , also contribute to the minimization of movement of the first substrate element  400  and the second substrate element  402 . Further, the first ring  236  and the second ring  238 , which reinforce the first bar  204  and the second bar  206  at the outer containment wall  200 , provide a structural strength to the catalyst substrate module  120  and restrict axial movement of the catalyst substrate module  120  to prevent tearing. The proposed design is targeted at the reduction of strain by the minimization of the substrate element movement. The existing catalyst substrates face issues of mechanical failure due to breaking up of substrate element. Such failures result from shock loads and the vibratory engine environment exhaust pressure on face of the catalyst substrate. Hence, due to the robust structure, the proposed catalyst substrate module  120  eliminates the potential of the above-mentioned issues. 
     The many features and advantages of the disclosure are apparent from the detailed specification, and, thus, it is intended by the appended claims to cover all such features and advantages of the disclosure, which fall within the true spirit and scope thereof. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the disclosure to the exact construction and operation illustrated and described, and, accordingly, all suitable modifications and equivalents may be resorted to that fall within the scope of the disclosure.