Patent Application
20150064079
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.
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.
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.
Referring to
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
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
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
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
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
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.
