Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N1/00—Silencing apparatus characterised by method of silencing
  • F01N1/08—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling
  • F01N1/083—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling using transversal baffles defining a tortuous path for the gases or successively throttling gas flow
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/28—Construction of catalytic reactors
  • F01N3/2892—Exhaust flow directors or the like, e.g. upstream of catalytic device
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
  • F01N2240/20—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a flow director or deflector
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N2470/00—Structure or shape of gas passages, pipes or tubes
  • F01N2470/18—Structure or shape of gas passages, pipes or tubes the axis of inlet or outlet tubes being other than the longitudinal axis of apparatus

Definitions

• the present disclosure relates generally to an exhaust flow distribution device. More particularly, the disclosure relates to a device capable of altering the exhaust gas velocity profile upstream of an exhaust aftertreatment device.
• Vehicle exhaust components for treating diesel engine exhaust often include a housing (e.g., a muffler body) containing an exhaust aftertreatment substrate (e.g., a catalytic converter substrate, a lean NOx catalyst substrate, an selective catalytic reduction (SCR ) substrate , a NOx trap substrate or a diesel particulate filter substrate).
• the housing often includes either a side inlet or an axially in-line inlet.
• a side inlet is generally aligned perpendicular to a central axis of the housing, while an axially in-line inlet is generally co-axially aligned with a central axis of the housing.
• the natural velocity profile of exhaust gas at the upstream face of an exhaust aftertreatment substrate positioned within a housing having an axial in-line inlet resembles a parabolic curve with the velocity maximum at the center of the flow distribution and decreasing significantly outwardly towards the periphery of the flow distribution.
• the natural velocity profile of exhaust gas at the upstream face of an exhaust aftertreatment substrate positioned within a side inlet housing has a maximum velocity at the half of the substrate located opposite from the inlet side of the housing.
• Non-uniform velocity flow distribution shortens the useful lives of the aftertreatment substrates and reduces their operational efficiency.
• One aspect of the present disclosure is to provide a flow distribution device that is constructed such that it effectively distributes flow without generating unacceptable levels of backpressure.
• the flow distribution device is adapted to distribute flow effectively in a side inlet vehicle exhaust component.
• FIG. 1 is a schematic view of a vehicle exhaust system component assembly having a flow distributor that includes features that are examples of inventive aspects in accordance with the principles of the present disclosure
• FIG. 2 is a cross-sectional view taken along section line 2-2.
• FIG. 1 is a schematic illustration of a vehicle exhaust system component 20 (e.g., a muffler or other enclosure in which one or more exhaust aftertreatment devices are contained) having features that are examples of inventive aspects in accordance with the principles of the present disclosure.
• the component 20 includes a main body 22 (e.g., a shell, housing, conduit, tube, etc.) having a side inlet 24 and a co-axial outlet 26.
• the main body 22 can be constructed of one or more pieces.
• the side inlet 24 has an axis 30 that is generally perpendicular to a central axis 32 of the main body 22.
• the outlet 26 and the main body 22 are depicted sharing the same axis 32.
• Aftertreatment devices are shown mounted within the main body 22.
• a catalytic converter 36 and a diesel particulate filter 38 are shown mounted within the main body 22.
• a flow distribution element 40 is shown positioned upstream from the catalytic converter 36.
• Flow arrows 42, 44, and 46 illustrate that the direction of exhaust gas flow is from the inlet 24 to the outlet 26.
• the term "generally perpendicular" means perpendicular or close to perpendicular.
• the flow distribution element 40 is preferably configured to improve exhaust flow uniformity across an upstream face 48 of the catalytic converter 36 without generating significant backpressure in the exhaust system 10.
• the flow distribution device can be used to distribute flow provided to other types of aftertreatment devices such as diesel particulate filters, deNOx catalysts, lean NOx catalyst devices, selective catalytic reduction (SCR) catalyst devices, lean NOx traps, or other devices for removing pollutants from the exhaust stream.
• aftertreatment devices such as diesel particulate filters, deNOx catalysts, lean NOx catalyst devices, selective catalytic reduction (SCR) catalyst devices, lean NOx traps, or other devices for removing pollutants from the exhaust stream.
• Catalytic converters are commonly used to convert carbon monoxides and hydrocarbons in the exhaust stream into carbon dioxide and water.
• Diesel particulate filters are used to remove particulate matter (e.g., carbon based particulate matter such as soot) from an exhaust stream.
• SCR systems are systems that selectively catalytically promote the reduction of NOx to N 2 .
• Lean NOx catalysts are catalysts capable of selectively catalytically promoting the reduction of NOx to N 2 in an oxygen rich environment with the use of hydrocarbons as reductants. For diesel engines, hydrocarbon emissions are too low to provide adequate NOx conversion, thus hydrocarbons are typically required to be injected into the exhaust stream upstream of the lean NOx catalysts.
• SCR' s use reductants such as urea or ammonia that are injected into the exhaust stream upstream of the SCR' s and that react with NOx at catalyzed surfaces of the SCR' s to cause the reduction of NOx to N 2 and H 2 O.
• reductants such as urea or ammonia that are injected into the exhaust stream upstream of the SCR' s and that react with NOx at catalyzed surfaces of the SCR' s to cause the reduction of NOx to N 2 and H 2 O.
• NOx traps use a material such as barium oxide to absorb NOx during lean burn operating conditions. During fuel rich operations, the NOx is desorbed and the selective reduction of NOx to N 2 in the presence of hydrocarbons is promoted via catalysts within the NOx traps.
• Diesel particulate filters can have a variety of known configurations.
• An exemplary configuration includes a monolith ceramic substrate having a "honey- comb" configuration of plugged passages as described in United States patent No. 4,851,015 that is hereby incorporated by reference in its entirety. Wire mesh configurations can also be used.
• the substrate can include a catalyst.
• Exemplary catalysts include precious metals such as platinum, palladium and rhodium, and other types of components such as base metals or zeolites.
• diesel particulate filters can have a particulate mass reduction efficiency greater than 75%. In other embodiments, diesel particulate filters can have a particulate mass reduction efficiency greater than 85%.
• diesel particulate filters can have a particulate mass reduction efficiency equal to or greater than 90%.
• the particulate mass reduction efficiency is determined by subtracting the particulate mass that enters the filter from the particulate mass that exits the filter, and by dividing the difference by the particulate mass that enters the filter.
• Catalytic converters can also have a variety of known configurations. Exemplary configurations include substrates defining channels that extend completely therethrough. Exemplary catalytic converter configurations having both corrugated metal and porous ceramic substrates/cores are described in United States patent No. 5,355,973, that is hereby incorporated by reference in its entirety.
• the substrates preferably include a catalyst that promotes an oxidation reaction at the catalytic converter.
• the substrate can be made of a catalyst, impregnated with a catalyst or coated with a catalyst.
• Exemplary oxidation catalysts include precious metals such as platinum, palladium and rhodium, and other types of components such as base metals or zeolites.
• a catalytic converter can have a cell density of at least 200 cells per square inch, or in the range of 200-400 cells per square inch.
• a preferred catalyst for a catalytic converter is platinum with a loading level greater than 30 grams/cubic foot of substrate. In other embodiments the precious metal loading level is in the range of 30-100 grams/cubic foot of substrate.
• the catalytic converter can be sized such that in use, the catalytic converter has a space velocity (volumetric flow rate through the catalytic converter/ volume of the catalytic converter) less than 150,000/hour or in the range of50,000-150,000/hour. Referring to FIGS.
• the flow distribution element 40 of the component 20 is positioned adjacent a portion 50 of the main body 22 that is opposite from the inlet 24.
• the flow distribution element 40 is depicted as a baffle 41 having a curved first edge 52 that matches the inner diameter of the main body 22.
• the baffle 41 also includes a second edge 54 that extends from one end 56 of the first edge 52 to an opposite end 58 of the first edge 52.
• the second edge 54 has a concave curvature while the first edge 52 has a convex curvature, and the edges cooperate to provide the baffle 41 with a crescent shaped outline/profile.
• the second edge 54 is defined by a radius that is in the range of 1.1 to 1.3 times as large as the inner radius of the main body 22.
• the first edge 52 matches the inner diameter of the main body 22 and extends from a first side 23 of the main body 22 to a second side 25 of the main body 22.
• the first and second sides 23, 25 are positioned on opposite sides of a central reference plane 27 that bisects the main body 22 along its length and also bisects the inlet pipe 24.
• the second edge 54 traverses an interior region of the main body 22 and extends from the first side 23 of the main body 22 across the central reference plane 27 to the second side 25 of the main body 22.
• the second edge 54 intersects with the first edge 52 at the first and second sides 23, 25 of the main body 22.
• the first edge 52 of the baffle 41 preferably seats against the inner diameter of the main body 22 at the portion 50 of the main body 22 that is opposite from the location of the inlet 24.
• the reference plane 27 is shown passing through portion 50 at location 51.
• the baffle 41 is located at the bottom of the main body 22 and the inlet is located at the top of the main body 22.
• the baffle 41 is shown having a height that extends upwardly from the bottom of the main body 22 toward the top of the main body 22 (e.g., the height dimension extends generally toward the inlet).
• the baffle 41 is shown aligned along a plane that is generally perpendicular to the central axis 32 of the main body 22.
• the baffle 41 is shown as a flat plate, the baffle 41 could also be curved.
• the exhaust gases are directed into the main body 22 through the inlet 24.
• the exhaust flow encounters the flow distribution device 40.
• the flow distribution element 40 forms a mixing wall/barrier positioned at the portion 50 of the main body 22 upon which flow from the inlet 24 impinges.
• the exhaust gases then flow over/through the flow distribution device 40 to the catalytic converter 36.
• flow is fairly evenly distributed by virtue of the flow distribution element 40.
• the exhaust flow travels through the diesel particulate filter and exits the main body 22 through the outlet 26.
• the flow distribution element 40 can also be referred to as a flow distribution plate, a flow distributor, a flow distribution member, a flow distribution structure or like terms.
• the main body 22 can also be referred to as a housing, an aftertreatment device housing, an enclosure, a conduit, or like terms.
• the inlet 24 can include a cylindrical inlet pipe, and the main body 22 can also be cylindrical in shape, hi one example embodiment, the inlet 24 can have a diameter in the range of 4-6 inches and the main body can have a diameter in the range of 9-12 inches.
• the flow distribution element 40 is preferably configured to provide generally uniform flow distribution across the upstream face of the catalytic converter 36 without causing additional backpressure. In one example embodiment, the flow distribution element 40 is configured to provide a ⁇ value greater than or equal to 0.95.
• ⁇ 7 is a calculated value representative of flow speed uniformity across the upstream area/face of a substrate (e.g., a catalytic converter substrate, a DPF substrate, an SCR substrate, a NOx absorber substrate, a lean NOx catalyst substrate, etc.).
• a substrate e.g., a catalytic converter substrate, a DPF substrate, an SCR substrate, a NOx absorber substrate, a lean NOx catalyst substrate, etc.
• A is the total area of the upstream face of the substrate.
• the total area A is formed by n discrete/localized areas.
• Vi is the exhaust flow velocity at each of the n discrete/localized areas, and V A is the average exhaust flow velocity across the total area A.
• a variety of factors control the effectiveness of the distribution element 40 for providing substantially uniform flow.
• Example factors include a spacing S defined between the distribution element 40 and the upstream face of the catalytic converter 36 and dimensions dl and d2 of the distribution element. The dimensions dl, d2 are measured relative to a reference line 31 that is tangent to the inner diameter of the main body 22 at the location 50.
• the dimension dl corresponds to the dimension of the distribution element 40 measured along the central reference plane 27 of the main body from the reference line 31 to the second edge 54 (i.e., at the center of the distribution element 40).
• the dimension d2 corresponds to the dimension of the distribution element 40 measured from the reference line 31 to the second edge 54 at locations that are laterally farthest from the central reference plane 27 (e.g., at peripheral/side portions of the distribution element 40 such as intersection points 56 and 58).
• the dimensions defined between the reference line 31 and the second edge 54 preferably gradually increase as the second edge extends away from the central reference plane 27.
• maximum dimensions are defined at the intersections between the edges 52, 54 of the distribution element 40 at the sides of the main body 22 and a minimum dimension is defined at the central reference plane 27. It has been determined by the inventors that the larger dimensions provided at the peripheral portions of the distribution element 40 assist in reducing the likelihood or magnitude of "hot-spots" caused by disproportionate amounts of flow at the lower peripheral regions of the catalytic converter.
• the spacing S and the dimensions dl and d2 are dependent on the flow distribution desired and the size and arrangement of the inlet 24 and the main body 22.
• the spacing S is less than 3 inches, or less than 2 inches, or less than 1 inch, or lest than 3/4 inch or about 5/8 inch
• the dimension dl is less than 50, 40 or 30 percent of a cross-dimension d3 measured along the central reference plane 27.
• the cross-dimension d3 corresponds to the inner diameter of the main body 22 or the outer diameter of the catalytic converter 36.
• the dimension dl is in the range of 10-40 percent, or 10-30 percent, or 20-40 percent, or 20-30 percent of the cross-dimension d3.
• the dimension dl is less than 5 inches, or less than 4 inches, or less than 3 inches, or in the range of 1-5 inches, or in the range of 1-4 inches, or in the range of 2-4 inches or in the range of 2-3 inches, hi still other embodiments, the spacing S is less than 20 percent of the cross-dimension d3, or less than 15 percent of the cross-dimension d3, or less than 10 percent of the cross-dimension d3, or less than 5 percent of the cross- dimension d3.
• the dimension d2 is preferably greater than the dimension dl .
• the dimension d2 is at least 1.25 times, or at least 1.5 times, or at least 1.75 times, or at least 2 times, or at least 2.5 times or at least 3 times as large as the dimension dl.
• the dimension dl is in the range of 10-30 percent of the cross-dimension d3, and the dimension d2 is in the range of 40-60 percent of the cross-dimension d3.
• the distribution element 40 can define a plurality of openings 90 (e.g., perforations) that allow exhaust to flow through the distribution element, hi one embodiment, the openings 90 each have a diameter of about .25 inches and are spaced apart from one another by .375 inch measured center-to-center. hi certain embodiments, no portion of the flow distribution element 40 extends past a mid-line 100 of the main body 22, and the flow distribution element 40 is shaped such that a central portion 102 of the flow distribution element 40 is spaced farther from the mid-line 100 than side portions 104 of the flow distribution element.
• openings 90 e.g., perforations
• flow distribution elements in accordance with the principles of the present disclosure can also be used in conduits having non- round (e.g., oval) cross-sectional shapes.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Exhaust Gas After Treatment (AREA)

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• 2009
  • 2009-12-02 US US12/629,195 patent/US20100170232A1/en not_active Abandoned
  • 2009-12-02 WO PCT/US2009/066410 patent/WO2010065637A1/en active Application Filing
  • 2009-12-02 EP EP09764679.8A patent/EP2370676B1/de not_active Not-in-force

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