Patent Publication Number: US-2017362981-A1

Title: Exhaust system including ionization assembly

Description:
BACKGROUND 
     Products of combustion in the form of exhaust gases may be directed through an exhaust system where the exhaust gases may be treated before being discharged to the environment or other suitable location. A variety of exhaust system configurations, and chemical and/or physical processing techniques may be used to remove and sequester products of combustion from the exhaust gases before discharging the remaining components. 
     SUMMARY 
     According to an aspect of the present disclosure, an exhaust system ionizes exhaust gases to remove products of combustion from an exhaust stream. The exhaust system includes an electrically conductive shell defining an exhaust pathway. The shell has a tapered portion that tapers inward to define a narrowing region of the exhaust pathway. The exhaust system further includes an ionization assembly and an electrical subsystem that applies an electrical potential difference between the shell and at least a portion of the ionization assembly located within the exhaust pathway. 
     The ionization assembly includes a support arm located within the exhaust pathway that extends into and along the narrowing region of the exhaust pathway. The ionization assembly further includes a plurality of electrically conductive discs mounted on and supported by the support arm. At least some of the discs are located within the narrowing region of the exhaust pathway, and are spaced apart from each other along a longitudinal axis of the exhaust pathway. The discs decrease in size relative to each other along the longitudinal axis with tapering of the shell. Components of the ionization assembly, such as the support arm and the discs are electrically insulated from the shell by an electrically insulating support structure. 
     A voltage source of the electrical subsystem includes a high electrical potential terminal in electrical communication with the shell, and a low electrical potential terminal in electrical communication with the discs to apply an electrical potential difference between the shell and the discs. Particles within exhaust gases traveling along the exhaust pathway are ionized and become negatively charged by the low electrical potential applied to the discs. These negatively charged particles are attracted by the high electrical potential of the shell. A filter element located along an inner surface of the tapered portion of the shell that surrounds the narrowing region of the exhaust pathway captures larger ionized particles, such as particulate matter or other products of combustion contained in the exhaust gases. 
     This Summary describes aspects of the present disclosure in a simplified form. This Summary is not intended to identify key features or essential features of claimed subject matter, nor is this Summary intended to limit the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  depicts an internal view of an example exhaust system. 
         FIG. 2  depicts an example external view of the exhaust system of  FIG. 1 . 
         FIG. 3  depicts another example external view of the exhaust system of  FIG. 1  with optional components omitted. 
         FIG. 4  depicts an exploded view of the example exhaust system. 
         FIG. 5  depicts the example insulating support structure of  FIG. 1  in further detail. 
         FIG. 6  depicts an example of an overlapping region between shell components of the exhaust system of  FIG. 1 . 
         FIGS. 7 and 8  depict additional aspects of the example ionization assembly of  FIG. 1  as exploded view and assembled views, respectively. 
         FIGS. 9 and 10  depict a non-limiting example of an electrically conductive disc in further detail. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  depicts an internal view of an example exhaust system  100  that ionizes exhaust gases to remove products of combustion and incomplete combustion from an exhaust stream. Exhaust system  100  includes an electrically conductive shell  110  defining an exhaust pathway  112 . Shell  110  forms a generally tubular structure to convey exhaust gases along exhaust pathway  112 . In this example, shell  110  may have a circular shape when viewed in section along a longitudinal axis  114  of shell  110 . In other examples, shell  110  may have a non-circular shape when viewed in section, such as a non-circular oval shape, polygonal shape, or other suitable shape. Example section views of shell  110  are depicted in  FIGS. 4-6 . 
     Shell  110  includes a tapered portion  128  that tapers inward toward longitudinal axis  114  in a first direction  116  along longitudinal axis  114 . Tapered portion  128  defines a narrowing region  118  of exhaust pathway  112  that narrows in the first direction  116  along longitudinal axis  114 . In this example, first direction  116  corresponds to a flow direction of exhaust gases along exhaust pathway  112  in which longitudinal axis  114  of shell  110  is oriented parallel to the X-coordinate axis. 
     Exhaust system  100  includes an ionization assembly  140 . Ionization assembly  140  includes a support arm  142  located within exhaust pathway  112 . Support arm  142  extends into and along at least a portion of narrowing region  118  of exhaust pathway  112 . Support arm  142  may be supported relative to shell  110  and electrically insulated from shell  110  by an electrically insulating support structure  144 . Support structure  144  serves as an electrical insulator that electrically insulates discs  146  and/or support arm  142  from shell  110 . In this example, support arm  142  projects from support structure  144  in the first direction  116  along longitudinal axis  114  and is collinear with the longitudinal axis. In other examples, support arm  142  may be parallel to and offset from the longitudinal axis. Also in other examples, support arm  142  may extend in an opposite or counter direction from the direct depicted in  FIG. 1  in which the support arm projects upstream from an electrically insulating support structure. 
       FIG. 1  depicts support structure  144  being located within the exhaust pathway. Support structure  144  may be secured to the shell at one or more points via one or more mounting surfaces of the support structure. In this example, support structure  144  has three mounting surfaces for securing the support structure to shell  110  at three points radially spaced apart from each other about longitudinal axis  114 . Two of these points are depicted in  FIG. 1  at  180  and  182 . Support structure  144  is depicted in further detail with reference to  FIGS. 4, 5, 7 , and  8 . 
     Ionization assembly  140  includes a plurality of electrically conductive discs  146  mounted on and supported by support arm  142 . In this example, ionization assembly  140  includes six discs, indicated individually by reference numerals  150 - 160 . In other examples, an ionization assembly may include a single electrically conductive disc or 2, 3, 4, 5, 7, 8, 9, 10 or more electrically conductive discs. At least some or all of discs  146  may be located within narrowing region  118  of exhaust pathway  112 . In other embodiments, narrowing region  118  may instead be a non-narrowing region, and expanding region, cylindrical, etc. 
     Discs  146  are spaced apart from each other along longitudinal axis  114  and along the support arm  142 . In at least some examples, some or all of discs  146  may have different sizes and/or shapes relative to some or all of the other discs. In this example, discs  146  have a circular shape when viewed along longitudinal axis  114 , and decrease in size (e.g., in diameter or width as measured in a plane that is orthogonal to longitudinal axis  114 ) relative to each other in first direction  116  along longitudinal axis  114  and along support arm  142 . For example, disc  150  is larger than disc  152 , disc  152  is larger than disc  154 , disc  154  is larger than disc  156 , disc  156  is larger than disc  158 , and disc  158  is larger than 160. In other examples, at least some or all of discs  146  may have the same size and/or shape relative to each other. Also in other examples, at least some or all of discs  146  may have a non-circular shape when viewed along longitudinal axis  114 , including a non-circular oval shape, polygonal shape, or other suitable shape. 
     Exhaust system  100  includes an electrical subsystem  170 . Electrical subsystem  170  includes a voltage source  172  having a high (e.g., positive charge relative to a ground reference) electrical potential terminal  174  in electrical communication with shell  110 , and a low (e.g., negative charge relative to a ground reference) electrical potential terminal  176  in electrical communication with discs  146 . In this example, a high electrical potential is applied to shell  110  by voltage source  172  via a first electrical pathway  178  that is in communication with high electrical potential terminal  174 , and a low electrical potential is applied by voltage source  172  via a second electrical pathway  179  to discs  146  via low electrical potential terminal  176  to create an electrical potential difference between shell  110  and discs  146 . In some examples, support arm  142  may take the form of an electrically conductive support arm that is also in electrical communication with low electrical potential terminal  176  (e.g., via electrical pathway  179 ) and with each of discs  146 , so that a low electrical potential is applied to both support arm  142  and discs  146 . As an example, support arm  142 , as an electrically conductive support arm, may form part of electrical pathway  179  that electrically couples discs  146  to low electrical potential terminal  176 . 
     Voltage source  172  is depicted schematically in  FIG. 1 , and may take other suitable forms and may be positioned at other suitable locations relative to shell  110 . Voltage source  172  may be implemented as an electric battery, an electric motor, or other suitable device or system that provides an electrical potential difference that may be applied between shell  110  and discs  146 . In some examples, one or both of electrical pathways  178 ,  179  may include one or more intermediate switches that enable one or both of the electrical pathways  178 ,  179  to be opened to disconnect voltage source  172  from exhaust system components, and thereby remove the electrical potential difference from between shell  110  and discs  146 . 
     During operation of exhaust system  100 , exhaust gases traveling along exhaust pathway  112  in the first direction  116  enter shell  110  via inlet portion  120 . Particles within the exhaust gases are ionized and become negatively charged by the low electrical potential applied to discs  146 . These negatively charged particles are attracted by the high electrical potential of shell  110 . Narrowing region  118  may further compress exhaust gases traveling along exhaust path  112  within the vicinity of discs  146  to further improve ionization of exhaust gases at surfaces of the discs and/or support arm  142 , which in turn increases the removal of exhaust components from the exhaust gases. 
     In at least some examples, exhaust system  100  may include a filter element  190  located along an inner surface of tapered portion  128  of the shell  110  that surrounds narrowing region  118  of exhaust pathway  112 . Filter element  190  captures ionized particles that are attracted to the high electrical potential of the shell, such as particulate matter or other combustion products contained within the exhaust gases. Remaining exhaust gases are discharged from shell  110  via outlet portion  134 . 
     Non-limiting use-environments for exhaust system  100  include within vehicle exhaust systems, building exhaust systems, building HVAC systems, building emergency/fire exhaust systems, and exhaust systems for electrical power generation to name a few examples. As a prophetic example, exhaust system  100  may eliminate approximately 80% of products of combustion from the exhaust gases without adding undue flow obstruction or backpressure to the exhaust pathway. Another potential benefit of the ionization of exhaust gases provided by exhaust system  100  includes the reduction of odors contained in the exhaust gases, for example, by the production of ozone via the ionization process. 
     In this example, filter element  190  covers interior surfaces of the tapered portion of the shell and tapers with the tapered portion of the shell. For example, filter element  190  tapers inward toward longitudinal axis  114  in the first direction  116  along longitudinal axis  114 , and forms a generally conical structure. Filter element  190  may have a circular shape when viewed in section along longitudinal axis  114 . In other examples, filter element  190  may have a non-circular shape when viewed in section (e.g., to conform with a shell having a non-circular shape), such as a non-circular oval shape, polygonal shape, or other suitable shape. Another view of filter element  190  is depicted in  FIG. 4 .  FIG. 1  further depicts an example in which a downstream end of filter element  190  extends beyond tapered portion  128  and projects into exhaust pathway  112 , as indicated at  192 . In other examples, filter element  190  may conform to interior walls of tapered portion  128  without extending beyond tapered portion  128  or without projecting into exhaust pathway  112 . Filter element  190  may take the form of a paper filter or other suitable filter type that is disposable or alternatively reusable. In some examples, filter element  190  may be omitted. If the filter element is omitted, ionized exhaust gas components that are attracted to the shell may adhere to interior surfaces of the shell and thereby removed from the exhaust gases that exit the exhaust system. 
       FIG. 2  depicts an example of an external view of exhaust system  100  of  FIG. 1 . Shell  110  from  FIG. 1  may be formed by one or more shell components. In this example, a shell is formed by an inlet shell component  210  and an outlet shell component  212  that join each other at an interface  214  to collectively define exhaust pathway  112 . An internal view of interface  214  is depicted in  FIG. 1  as including an overlapping region  136  depicted in  FIG. 1 , in which outlet shell component  212  surrounds and overlaps with inlet shell component  210  within overlapping region  136 . In other examples, shell  110  may be formed by a single shell component, or by three or more shell components. 
     In this example, inlet shell component  210  includes an inlet portion  120 , an inlet-side tapered portion  122  that tapers outward away from longitudinal axis  114  in the first direction  116  (shown in  FIG. 1 ), and a first intermediate portion  124 . Also in this example, outlet shell component  212  includes a second intermediate portion  126  that interfaces with first intermediate portion  124  at interface  214 . Outlet shell component  212  further includes previously described tapered portion  128 , and an outlet portion  134 . Outlet shell component  212  may optionally include an additional outlet-side tapered portion  132  that further tapers inward toward longitudinal axis  114  in the first direction  116 , and an additional intermediate portion  130  located between tapered portion  128  and outlet-side tapered portion  132 . In other examples, intermediate portion  130  and outlet-side tapered portion  132  may be omitted, such that tapered portion  128  joins outlet portion  134 , as depicted in  FIG. 3 , for example. 
       FIG. 4  depicts an exploded view of exhaust system  100  of  FIG. 1 . Within  FIG. 4 , first intermediate portion  124  of inlet shell component  210  may include a plurality of keyways  412  (or slots) located along a terminal end of the inlet shell component that accommodate a corresponding plurality of shafts  410  (or other suitable key structures) that project from an interior surface of second intermediate portion  126  of outlet shell component  212 .  FIG. 6  depicts additional aspects of keyways  412  and shafts  410  in further detail. Shafts  410  may be inserted into keyways  412  and inlet shell component  210  may be rotated relative to outlet shell component  212  to lock or otherwise secure shell component  210  to outlet shell component  212 . Opening  420  in inlet shell component  210  is aligned with opening  422  in outlet shell component  212  when shafts  410  are fully inserted and rotated into keyways  412 . A fastener  424  (e.g., a bolt, screw, pin, or other suitable fastener) may be inserted into openings  420  and  422  to inhibit rotation of inlet shell component  210  relative to outlet shell component  212 , thereby precluding shafts  410  from exiting keyways  412 . 
       FIG. 4  further depicts insulating support structure  144  including three arms  460 ,  462 , and  464  that are secured to inlet shell component  210 .  FIGS. 5, 7, and 8  depict additional views of insulating support structure  144 . Inlet shell component  210  further includes an opening  416  through which a fastener  418  (e.g., e.g., a bolt, screw, pin, or other suitable fastener) may be inserted and engaged with an opening  414  in a terminal end of arm  462  to secure insulating support structure  144  to the shell. Arm  464  may be secured to inlet shell component  210  in a similar manner as arm  462 . Arm  460  includes an opening  436  that aligns with opening  438  in inlet shell component  210 . A deformable fastener  440  may be inserted through opening  438  to engage with opening  436  of arm  460 . A compression cap  442  engages with deformable fastener  440  to provide a clamping force that secures one or more wires, cables, or other suitable electrical pathways that pass through opening  450 . As shown in further detail in  FIGS. 5, 7 and 8 , opening  450  passes through cap  442 , deformable fastener  440 , inlet shell component  210  (via opening  438 ), and arm  460  (via opening  436 ), and connects to opening  428  located in a hub of insulating support structure  144 . Electrical pathway  179  (shown in  FIG. 1 ) may pass through opening  450  to be connected with electrically conductive components of the ionization assembly, such as discs  146  and support arm  142 . 
     Support arm  142  may be secured to insulating support structure  144  at opening  428  via an intermediate fastener  426 . Opening  428  passes through the hub of insulating support structure  144 , enabling a fastener  432  located on an upstream side of support structure  144  to engage with intermediate fastener  426  through opening  428 . A cover  434  may be inserted into opening  428  over fastener  432  on the upstream side of insulating support structure  144  to provide a more aerodynamic upstream surface. 
       FIG. 5  depicts insulating support structure  144  and surrounding first intermediate shell portion  124  in further detail as viewed along longitudinal axis  114 . Insulating support structure  144  is shown in further detail including hub  510 , which joins arms  460 ,  462 , and  464  that radially project from the hub. Arms  460 ,  462 , and  464  are depicted as each including a number of fin structures. Arms  462  and  464  are secured to first intermediate shell portion  124  by fasteners  418  inserted into openings  414  formed at a terminal end of arms  462  and  464 . Inlet portion  120  is depicted in  FIG. 5  for illustrative purposes, and is located upstream of insulating support structure  144 . Opening  450  is depicted passing through cap  442 , deformable fastener  440 , arm  460 , and joins with opening  428  formed in hub  510 . Arm  460  is secured to first intermediate shell portion  124  by deformable fastener  440 , as depicted in further detail in  FIGS. 7 and 8 . 
       FIG. 6  depicts overlapping region  136  of interface  214  between shell components  210  and  212  in further detail, as viewed along longitudinal axis  114 . First intermediate portion  124  of inlet shell component  210  is depicted within second intermediate portion  126  of outlet shell component  212 . Shafts  410  are engaged with keyways  412  in  FIG. 6 . Fastener  424  passes through opening  422  in first intermediate portion  126  and engages with second intermediate portion  124  via opening  420  to inhibit portions  124  and  126  of the shell from rotating and/or disengaging from each other. 
       FIG. 7  depicts additional aspects of ionization assembly  140  in an exploded view. Within  FIG. 7 , an internal view of insulating support structure is provided, which reveals internal threads within opening  436  that engage with external threads  718  of a lower portion of deformable fastener  440 . Deformable fastener  440  further includes an upper portion that includes external threads  720  that engage internal threads  722  of compression cap  442 . When compression cap  442  is threaded onto deformable fastener  440  via threads  720  and  722 , internal wall surfaces that define an interior region  726  of compression cap  442  contact deformable elements  724  causing the deformable elements to deform inward, thereby providing a clamping force on an object (e.g., a wire, cable, or other electrical pathway) that passes through deformable fastener  440  via opening  450 . 
     Opening  450  joins opening  428  that passes through hub  510 . Fastener  432  having external threads may be inserted into opening  428  on the upstream side of support structure  144  where it engages internal threads of intermediate fastener  426  to retain intermediate fastener within opening  428  on the downstream side of the support structure. Cap  434  may be inserted behind fastener  432  to cover opening  428 . When fastener  432  is threaded onto intermediate fastener  426 , the fasteners may collectively provide a clamping force upon a narrowed region  714  of opening  428  of the support structure. Intermediate fastener  426  further includes internal threads  711  that accommodate external threads of support arm  142 . In at least some examples, intermediate fastener  426  includes an opening  716  that aligns with opening  450  when threads  712  are engaged with threads of fastener  432 . Opening  716  may accommodate one or more wires, cables, electrical connectors, or other suitable electrical pathways that pass through opening  450  from outside of the ionization assembly. 
       FIG. 8  depicts components of ionization assembly  140  in an assembled configuration. In  FIG. 8 , a wire  812  passing through opening  450  is connected to a low electrical potential of a voltage source. Wire  812  terminates at a conductive element  810  (e.g., an electrical connector) that is sized and shaped for insertion into opening  716  of intermediate fastener  426 . In some examples, fastener  432  may extend to or beyond opening  716  and may contact conductive element  810  when threaded into threads  712  of intermediate fastener  426  to retain or otherwise clamp conductive element  810  within opening  716 . Additionally or alternatively, deformable elements  724  may clamp onto wire  812  to retain conductive element  810  within opening  716  when cap  442  is threaded onto deformable fastener  440 . Intermediate fastener  426  and fastener  432  may be electrically conductive to establish an electrical pathway between conductive element  810  and support arm  142  upon which the electrically conductive discs are mounted and supported. 
       FIGS. 9 and 10  depict an example of an electrically conductive disc  900 . Disc  900  is a non-limiting example of any of the previously described electrically conductive discs  146  of  FIGS. 1 and 4 .  FIGS. 9 and 10  provide an example orientation of disc  900  relative to the same coordinate system of  FIGS. 1 and 4 . For example,  FIG. 9  depicts a face  910  of disc  900  presented orthogonal to the view provided by  FIG. 9 , which is parallel with the X-coordinate axis and longitudinal axis  114  of  FIG. 1 .  FIG. 10  depicts disc  900  in the same orientation as discs  146  of  FIG. 1 . 
     In this example, disc  900  has a circular shape bounded by outer edge  912 . Disc  900  has an opening  916  located at a centroid of its circular shaped face  910  to accommodate a support arm, such as previously described support arm  142 . In some examples, a diameter of opening  916  may vary among or between each disc of an ionization assembly that contains a plurality of electrically conductive discs. In this example, a support arm for supporting the plurality of discs may vary in size (e.g., diameter) and/or shape along its length to define a particular location along its length where each disc resides. For example, referring also to  FIG. 1 , a size (e.g., a diameter) of support arm  142  decreases in a step-wise manner between each disc as the support arm extends away from insulating support structure  144  and along longitudinal axis  114  in the first direction  116 . In this example, each of the plurality of discs  146  has an opening at its centroid for accommodating support  142 , in which the size (e.g., diameter) of each opening decreases as the size of the disc decreases. 
     Also in this example, disc  900  tapers toward outer edge  912  as indicated by tapered region  914  to provide a sharp outer edge or corner that may improve ionization of exhaust gas components flowing over or past the disc.  FIG. 10  depicts an example taper angle  1000  for tapered region  914 . In  FIG. 10 , taper angle  1000  is measured relative to face  910  of the disc. As a non-limiting example, taper angle  1000  may be 28 degrees. As another example, taper angle  1000  may be between 25 degrees and 30 degrees. As yet another example, taper angle  1000  may be greater than zero degrees and less than 30 degrees. As yet another example, taper angle  1000  may be an angle greater than 28 degrees. A taper angle may be the same for either side of a disc to provide a symmetric configuration, such as depicted in  FIG. 10 . In other examples, a taper angle on one side of a disc may differ from a taper angle on an opposite side of the disc. 
     The various components described as being electrically conductive may be formed from any suitable material that provides substantial electrical conductivity, including materials that are or include electrically conductive metals such as copper, steel, aluminum, and iron, to name a few non-limiting examples. Components described as being electrically insulating, such as support structure  144  of ionization assembly  140 , may be formed from any suitable material that does not provide substantial electrical conductivity. Where the electrically insulating material is located within the exhaust pathway that may contain exhaust gases of relatively high temperatures or is otherwise used in high temperature environments (such as support structure  144  located within the exhaust pathway) suitable electrically insulating materials may include ceramic, heat-tolerant polymers, or other heat tolerant electrical insulators. 
     The drawings accompanying this disclosure include schematic representations of example geometries and configurations. These drawings are not necessarily to scale. A non-limiting example of physical measurements for components of exhaust system  100  is provided below. These physical measurements in combination with each other describe a non-limiting example of the relative sizes and shapes of exhaust system components. These relative sizes and shapes may vary (e.g., by 10%, by 20%, or more) from the specific physical measurements described herein while still providing suitable or adequate removal of exhaust gas components. 
     In a non-limiting example, each of discs  146  have a thickness of 1 cm and are spaced 20 cm apart from each other on support structure  142 . Disc  150  has a diameter of 75.7 cm and an opening at its centroid of 9 cm. Disc  152  has a diameter of 66.2 cm and an opening at its centroid of 8 cm. Disc  154  has a diameter of 56.7 cm and an opening at its centroid of 7 cm. Disc  156  has a diameter of 47.2 cm and an opening at its centroid of 6 cm. Disc  158  has a diameter of 37.7 cm and an opening at its centroid of 5 cm. Disc  150  has a diameter of 28.2 cm and an opening at its centroid of 4 cm. Outlet shell component  212  has a total length, as measured along longitudinal axis  114  of 270 cm. Tapered portion  128  has a length of approximately 182.3 cm, and tapers from a diameter of 111.6 cm to 42 cm with walls having a taper angle of 11 degrees relative to longitudinal axis  114 . Inlet shell component  210  has a total length of 155 cm as measured along longitudinal axis  114  and varies in diameter from 68.4 cm to 110 cm. Support structure  144  has a thickness of 40 cm as measured along the longitudinal axis  114 , with arms  460 ,  462 , and  464  radially projecting from hub  510  at approximately 120 degrees relative to each other. Filter element  190  has a total length of 178.3 cm as measured along the longitudinal axis, and tapers from a diameter of 109-110 cm to 41 cm with walls having a taper angle of 11 degrees relative to longitudinal axis  114 . 
     The various examples disclosed herein include features that may be used individually or in any combination. Claimed subject matter is not limited to the combination of features disclosed by an individual example, since features that are present in two or more of the disclosed examples may be used together in other combinations. Accordingly, it should be understood that the disclosed examples are illustrative and not restrictive. Variations to the disclosed examples that fall within the metes and bounds of the claims or equivalence of such metes and bounds are intended to be embraced by the claims.