WO2008074414A1 - Exhaust pipe for an exhaust system of an internal combustion engine - Google Patents

Exhaust pipe for an exhaust system of an internal combustion engine Download PDF

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Publication number
WO2008074414A1
WO2008074414A1 PCT/EP2007/010728 EP2007010728W WO2008074414A1 WO 2008074414 A1 WO2008074414 A1 WO 2008074414A1 EP 2007010728 W EP2007010728 W EP 2007010728W WO 2008074414 A1 WO2008074414 A1 WO 2008074414A1
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WO
WIPO (PCT)
Prior art keywords
exhaust pipe
guide element
exhaust
curve
outside
Prior art date
Application number
PCT/EP2007/010728
Other languages
German (de)
French (fr)
Inventor
Hans-Christoph Hossfeld
Original Assignee
Emcon Technologies Germany (Augsburg) Gmbh
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Filing date
Publication date
Application filed by Emcon Technologies Germany (Augsburg) Gmbh filed Critical Emcon Technologies Germany (Augsburg) Gmbh
Publication of WO2008074414A1 publication Critical patent/WO2008074414A1/en

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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
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/20—Mixing gases with liquids
    • B01F23/21—Mixing gases with liquids by introducing liquids into gaseous media
    • B01F23/213—Mixing gases with liquids by introducing liquids into gaseous media by spraying or atomising of the liquids
    • B01F23/2132—Mixing gases with liquids by introducing liquids into gaseous media by spraying or atomising of the liquids using nozzles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
    • B01F25/3131—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit with additional mixing means other than injector mixers, e.g. screens, baffles or rotating elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/431—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor
    • B01F25/4316—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor the baffles being flat pieces of material, e.g. intermeshing, fixed to the wall or fixed on a central rod
    • B01F25/43161—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor the baffles being flat pieces of material, e.g. intermeshing, fixed to the wall or fixed on a central rod composed of consecutive sections of flat pieces of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/431—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor
    • B01F25/43197—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor characterised by the mounting of the baffles or obstructions
    • B01F25/431971—Mounted on the wall
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/433—Mixing tubes wherein the shape of the tube influences the mixing, e.g. mixing tubes with varying cross-section or provided with inwardly extending profiles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/433—Mixing tubes wherein the shape of the tube influences the mixing, e.g. mixing tubes with varying cross-section or provided with inwardly extending profiles
    • B01F25/4331—Mixers with bended, curved, coiled, wounded mixing tubes or comprising elements for bending the 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
    • F01N3/18—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 methods of operation; Control
    • F01N3/20—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 methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • 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
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/08—Other arrangements or adaptations of exhaust conduits
    • 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
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/10—Adding substances to exhaust gases the substance being heated, e.g. by heating tank or supply line of the added substance
    • F01N2610/102—Adding substances to exhaust gases the substance being heated, e.g. by heating tank or supply line of the added substance after addition to exhaust gases, e.g. by a passively or actively heated surface in the exhaust conduit
    • 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
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F01N3/025—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust
    • F01N3/0253—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust adding fuel to exhaust gases
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the invention relates to an exhaust pipe for an exhaust system of an internal combustion engine.
  • urea may be injected upstream of an SCR catalyst to provide ammonia as a reductant for the nitrogen oxides present in the exhaust.
  • reductant such as fuel may be supplied to controllably burn off particulate trapped in the filter.
  • the general rule is that the liquid to be introduced should be distributed as homogeneously as possible in the exhaust gas stream, so that a uniform effect occurs. It should also be prevented that the liquid settles to the pipe walls, which could cause corrosion.
  • the object of the invention is thus to achieve a uniform distribution of an introduced liquid in the exhaust stream with little effort and high reliability.
  • the invention provides an exhaust pipe for an exhaust system of an internal combustion engine with at least one guide element for influencing the flow, wherein the exhaust pipe has a curvature and the guide element is arranged in the region of the curvature on the inside of the curve and / or on the outside of the curve.
  • the guide element which is arranged in the region of the curvature, a swirl is given to the entire exhaust gas flow in the interior of the tube, which leads to a good turbulence and thus to a good distribution of a liquid injected into the exhaust gas flow.
  • contamination of the tube walls by the liquid such as by setting the liquid on the tube walls, avoided.
  • the swirling of the exhaust gas stream splits droplets of the liquid into smaller parts, with the splitting of the droplets destroying a low-reaction layer which surrounds the droplets.
  • the smaller parts evaporate faster.
  • ammonia acts as a reducing agent for the nitrogen oxides present in the exhaust gas.
  • the guide element is provided on the inside of the curve and arranged at an acute angle to the flow direction. Due to the acute angle between the guide element and the
  • Flow direction of the exhaust stream (seen in the direction of flow) is stimulated to better mixing.
  • the guide element is provided on the outside of the curve and arranged at an obtuse angle to the flow direction. Since the guide element is arranged at an obtuse angle to the flow direction of the exhaust gas flow, the exhaust gas flow is directed on the outside of the curve in the direction of the side walls of the tube. This prevents the oxidizable liquid settles on the outside of the curve.
  • the guide element is embossed in the exhaust pipe.
  • the exhaust pipe and the guide element are thus integrally formed.
  • the guide element may alternatively be formed from a separate metal part.
  • the guide element is embossed separately in a metal part, then introduced into the exhaust pipe and there, for example. fixed by welding.
  • FIG. 1 shows a part of an exhaust system of an internal combustion engine with an exhaust pipe according to the invention
  • FIG. 2 shows on an enlarged scale the region of FIG. 1 designated by X
  • FIG. 3 shows a developed view of the curve-inside section of the exhaust pipe with guide elements
  • FIG. 4 shows an unwound view of the curve-outside section of the exhaust pipe with guide elements
  • FIG. 5 is a detail view of one of the guide elements of Figure 4 in the exhaust pipe.
  • FIG. 6 is a representation of the flow conditions in the exhaust pipe, from which the turbulence of the exhaust stream is visible.
  • FIG. 1 shows part of an exhaust system of an internal combustion engine.
  • FIG. 1 shows an SCR catalytic converter 10, which is of a type
  • an oxidizable liquid is injected via an injection nozzle 12 into the exhaust gas stream flowing in an exhaust pipe 14.
  • Liquid is e.g. Urea, so that ammonia is provided as a reducing agent for the nitrogen oxides present in the exhaust gas.
  • the exhaust pipe 14 is shown in Figure 2 in a partial area in which the
  • Exhaust pipe 14 is curved.
  • Figures 3 and 4 show the exhaust pipe 14 unwound;
  • FIG. 3 shows a section of the exhaust pipe 14 in the region of a curve inside 16 and
  • FIG. 4 shows a section of the exhaust pipe 14 in the region of a curve outside 18.
  • both on the inside of the curve 16 and on the outside of the curve 18 guide elements 20 are provided which swirl the exhaust gas flow and thereby distribute the injected, oxidizable liquid uniformly in the exhaust stream. Further, the vanes 20 prevent contamination of the tube walls by the introduced liquid by avoiding a settling of the liquid on the tube walls.
  • Flow direction A of the exhaust stream are arranged.
  • the two parts of the guide element 20 approach each other in the flow direction A, wherein a
  • Opening or a distance 22 between the two parts is formed.
  • oxidizable liquid is directed by the guide elements 20 in the direction of the opening 22.
  • the guide elements 20 thus cause a (seen in the direction of flow A) confluence of the exhaust stream.
  • FIG. 5 shows the flow conditions on the outside of the curve 18.
  • guide elements 20 Although only three successively arranged guide elements 20 are shown on the inner side of the curve and on the outer side 16, 18, a plurality of guide elements 20 that are not in alignment could also be arranged.
  • the guide elements 20 can either be embossed directly into the pipe wall or formed in a separate metal part and then attached to the pipe wall, for example by welding.
  • the arrangement of the guide elements 20 turbulence of the exhaust gas flow are achieved, as shown in Figure 6.
  • the exhaust gas stream with the injected liquid flows along the pipe wall (with respect to FIG. 6) upwards to the curve outside 18.
  • the exhaust gas flow then flows centrally in the direction of the inside of the curve 16, from where it flows again along the pipe wall in the direction of the curve outside 18.
  • Two streams are created, each of which flows from the center to the respective lateral pipe wall.
  • the speed of the exhaust gas flow is highest, in particular on the outside of the curve 18 and in the region near the outside of the curve 18.
  • the described vanes 20 can also be used with other liquids that are introduced into the exhaust stream.

Abstract

The invention relates to an exhaust pipe for an exhaust system of an internal combustion engine, comprising at least one guide element (20) for influencing the flow, wherein the exhaust pipe (14) has a curvature and the guide element (20) is arranged in the region of the curvature on the inside of the curve (16) and/or on the outside of the curve (18).

Description

Abgasrohr für eine Abgasanlage einer Verbrennungskraftmaschine Exhaust pipe for an exhaust system of an internal combustion engine
Die Erfindung betrifft ein Abgasrohr für eine Abgasanlage einer Verbrennungskraftmaschine.The invention relates to an exhaust pipe for an exhaust system of an internal combustion engine.
Bei modernen Abgassystemen ist es manchmal erforderlich, in den Abgasstrom eine oxidierbare Flüssigkeit einzubringen, um bestimmte Reaktionen hervorzurufen. Beispielsweise kann stromaufwärts eines SCR-Katalysators Harnstoff eingespritzt werden, um Ammoniak als Reduktionsmittel für die im Abgas vorhandenen Stickoxide bereitzustellen. Auch kann stromaufwärts eines Partikelfilters Reduktionsmittel wie zum Beispiel Kraftstoff zugeführt werden, um die im Filter zurückgehaltenen Partikel kontrolliert abzubrennen. Allgemein gilt dabei, daß die einzubringende Flüssigkeit möglichst homogen im Abgasstrom verteilt werden soll, damit eine gleichmäßige Wirkung eintritt. Auch soll verhindert werden, daß sich die Flüssigkeit an den Rohrwänden absetzt, was Korrosion verursachen könnte.In modern exhaust systems, it is sometimes necessary to introduce into the exhaust stream an oxidizable liquid to cause certain reactions. For example, urea may be injected upstream of an SCR catalyst to provide ammonia as a reductant for the nitrogen oxides present in the exhaust. Also, upstream of a particulate filter, reductant such as fuel may be supplied to controllably burn off particulate trapped in the filter. The general rule is that the liquid to be introduced should be distributed as homogeneously as possible in the exhaust gas stream, so that a uniform effect occurs. It should also be prevented that the liquid settles to the pipe walls, which could cause corrosion.
Die Aufgabe der Erfindung besteht somit darin, mit geringem Aufwand und hoher Zuverlässigkeit eine gleichmäßige Verteilung einer eingebrachten Flüssigkeit im Abgasstrom zu erreichen.The object of the invention is thus to achieve a uniform distribution of an introduced liquid in the exhaust stream with little effort and high reliability.
Zu diesem Zweck sieht die Erfindung ein Abgasrohr für eine Abgasanlage einer Verbrennungskraftmaschine vor mit wenigstens einem Leitelement zur Strömungsbeeinflussung, wobei das Abgasrohr eine Krümmung hat und das Leitelement im Bereich der Krümmung an der Kurveninnenseite und/oder an der Kurvenaußenseite angeordnet ist. Durch das Leitelement, das im Bereich der Krümmung angeordnet ist, wird dem gesamten Abgasstrom im Inneren des Rohres ein Drall erteilt, der zu einer guten Verwirbelung und somit zu einer guten Verteilung einer in den Abgasstrom eingespritzten Flüssigkeit führt. Zudem wird eine Verunreinigung der Rohrwände durch die Flüssigkeit, etwa durch ein Festsetzen der Flüssigkeit an den Rohrwänden, vermieden. Ferner werden durch die Verwirbelung des Abgasstromes Tröpfchen der Flüssigkeit in kleinere Teile gespalten, wobei beim Spalten der Tröpfchen eine reaktionsarme Schicht, die die Tröpfchen umgibt, zerstört wird. Die kleineren Teile verdampfen schneller. Bei einem SCR-Katalysator, bei dem die eingespritzte Flüssigkeit Harnstoff ist, wird so früher Ammoniak freigesetzt, der als Reduktionsmittel für die im Abgas vorhandenen Stickoxide wirkt.For this purpose, the invention provides an exhaust pipe for an exhaust system of an internal combustion engine with at least one guide element for influencing the flow, wherein the exhaust pipe has a curvature and the guide element is arranged in the region of the curvature on the inside of the curve and / or on the outside of the curve. By the guide element, which is arranged in the region of the curvature, a swirl is given to the entire exhaust gas flow in the interior of the tube, which leads to a good turbulence and thus to a good distribution of a liquid injected into the exhaust gas flow. In addition, contamination of the tube walls by the liquid, such as by setting the liquid on the tube walls, avoided. Furthermore, the swirling of the exhaust gas stream splits droplets of the liquid into smaller parts, with the splitting of the droplets destroying a low-reaction layer which surrounds the droplets. The smaller parts evaporate faster. In an SCR catalyst in which the injected liquid is urea, is so released earlier ammonia, which acts as a reducing agent for the nitrogen oxides present in the exhaust gas.
Gemäß einer Ausführungsform ist das Leitelement an der Kurveninnenseite vorgesehen und in einem spitzen Winkel zur Strömungsrichtung angeordnet. Aufgrund des spitzen Winkels zwischen dem Leitelement und derAccording to one embodiment, the guide element is provided on the inside of the curve and arranged at an acute angle to the flow direction. Due to the acute angle between the guide element and the
Strömungsrichtung wird der Abgasstrom (in Strömungsrichtung gesehen) zu einer besseren Durchmischung angeregt.Flow direction of the exhaust stream (seen in the direction of flow) is stimulated to better mixing.
Gemäß einer anderen Ausführungsform ist das Leitelement an der Kurvenaußenseite vorgesehen und in einem stumpfen Winkel zur Strömungsrichtung angeordnet. Da das Leitelement in einem stumpfen Winkel zur Strömungsrichtung des Abgasstromes angeordnet ist, wird der Abgasstrom an der Kurvenaußenseite in Richtung der Seitenwände des Rohres gelenkt. Dadurch wird verhindert, daß sich die oxidierbare Flüssigkeit an der Kurvenaußenseite absetzt.According to another embodiment, the guide element is provided on the outside of the curve and arranged at an obtuse angle to the flow direction. Since the guide element is arranged at an obtuse angle to the flow direction of the exhaust gas flow, the exhaust gas flow is directed on the outside of the curve in the direction of the side walls of the tube. This prevents the oxidizable liquid settles on the outside of the curve.
Zur Unterstützung der Verwirbelung des Abgasstroms besteht dasTo support the turbulence of the exhaust stream is the
Leitelement aus zwei Teilen.Guide element of two parts.
Gemäß einer bevorzugten Ausführungsform ist das Leitelement in das Abgasrohr geprägt. Das Abgasrohr und das Leitelement sind also einstückig ausgebildet.According to a preferred embodiment, the guide element is embossed in the exhaust pipe. The exhaust pipe and the guide element are thus integrally formed.
Das Leitelement kann alternativ aus einem separaten Metallteil geformt sein.The guide element may alternatively be formed from a separate metal part.
Das Leitelement wird separat in einem Metallteil geprägt, anschließend in das Abgasrohr eingebracht und dort z.B. durch Schweißen befestigt.The guide element is embossed separately in a metal part, then introduced into the exhaust pipe and there, for example. fixed by welding.
Weitere Merkmale und Vorteile ergeben sich aus den Unteransprüchen.Further features and advantages emerge from the subclaims.
Die Erfindung wird nachfolgend anhand einer Ausführungsform beschrieben, die in den Zeichnungen dargestellt ist. In den Zeichnungen zeigen:The invention will be described below with reference to an embodiment shown in the drawings. In the drawings show:
- Figur 1 einen Teil einer Abgasanlage einer Verbrennungskraftmaschine mit einem erfindungsgemäßen Abgasrohr,FIG. 1 shows a part of an exhaust system of an internal combustion engine with an exhaust pipe according to the invention,
- Figur 2 in vergrößertem Maßstab den mit X bezeichneten Bereich von Figur 1 , - Figur 3 eine abgewickelte Ansicht des kurveninnenseitigen Abschnittes des Abgasrohres mit Leitelementen,FIG. 2 shows on an enlarged scale the region of FIG. 1 designated by X, FIG. 3 shows a developed view of the curve-inside section of the exhaust pipe with guide elements,
- Figur 4 eine abgewickelte Ansicht des kurvenaußenseitigen Abschnittes des Abgasrohres mit Leitelementen,FIG. 4 shows an unwound view of the curve-outside section of the exhaust pipe with guide elements,
- Figur 5 eine Detailansicht eines der Leitelemente von Figur 4 im Abgasrohr, und- Figure 5 is a detail view of one of the guide elements of Figure 4 in the exhaust pipe, and
- Figur 6 eine Darstellung der Strömungsverhältnisse im Abgasrohr, aus der die Verwirbelung des Abgasstromes ersichtlich wird.- Figure 6 is a representation of the flow conditions in the exhaust pipe, from which the turbulence of the exhaust stream is visible.
In Figur 1 ist ein Teil einer Abgasanlage einer Verbrennungskraftmaschine gezeigt. Insbesondere zeigt Figur 1 einen SCR-Katalysator 10, der von einemFIG. 1 shows part of an exhaust system of an internal combustion engine. In particular, FIG. 1 shows an SCR catalytic converter 10, which is of a type
Abgasstrom in Strömungsrichtung A durchströmt wird. Stromaufwärts des SCR-Exhaust gas flow in the flow direction A is flowed through. Upstream of the SCR
Katalysators 10 wird eine oxidierbare Flüssigkeit über eine Einspritzdüse 12 in den in einem Abgasrohr 14 strömenden Abgasstrom eingespritzt. Die oxidierbareCatalyst 10, an oxidizable liquid is injected via an injection nozzle 12 into the exhaust gas stream flowing in an exhaust pipe 14. The oxidizable
Flüssigkeit ist z.B. Harnstoff, so daß Ammoniak als Reduktionsmittel für die im Abgas vorhandenen Stickoxide bereitgestellt wird.Liquid is e.g. Urea, so that ammonia is provided as a reducing agent for the nitrogen oxides present in the exhaust gas.
Das Abgasrohr 14 ist in Figur 2 in einem Teilbereich dargestellt, in dem dasThe exhaust pipe 14 is shown in Figure 2 in a partial area in which the
Abgasrohr 14 gekrümmt ist. Figuren 3 und 4 zeigen das Abgasrohr 14 abgewickelt; und zwar Figur 3 einen Abschnitt des Abgasrohres 14 im Bereich einer Kurveninnenseite 16 und Figur 4 einen Abschnitt des Abgasrohres 14 im Bereich einer Kurvenaußenseite 18.Exhaust pipe 14 is curved. Figures 3 and 4 show the exhaust pipe 14 unwound; FIG. 3 shows a section of the exhaust pipe 14 in the region of a curve inside 16 and FIG. 4 shows a section of the exhaust pipe 14 in the region of a curve outside 18.
Sowohl an der Kurveninnenseite 16 als auch an der Kurvenaußenseite 18 sind Leitelemente 20 vorgesehen, die den Abgasstrom verwirbeln und dabei die eingespritzte, oxidierbare Flüssigkeit gleichmäßig im Abgasstrom verteilen. Ferner verhindern die Leitelemente 20 eine Verunreinigung der Rohrwände durch die eingebrachte Flüssigkeit, indem ein Festsetzen der Flüssigkeit an den Rohrwänden vermieden wird.Both on the inside of the curve 16 and on the outside of the curve 18 guide elements 20 are provided which swirl the exhaust gas flow and thereby distribute the injected, oxidizable liquid uniformly in the exhaust stream. Further, the vanes 20 prevent contamination of the tube walls by the introduced liquid by avoiding a settling of the liquid on the tube walls.
Das an der Kurveninnenseite 16 angeordnete Leitelement 20 (Figur 3) besteht aus zwei Teilen, die jeweils in einem spitzen Winkel α zurThe arranged on the inside of the curve 16 guide element 20 (Figure 3) consists of two parts, each at an acute angle α to
Strömungsrichtung A des Abgasstromes angeordnet sind. Die beiden Teile des Leitelementes 20 nähern sich in Strömungsrichtung A aneinander an, wobei eineFlow direction A of the exhaust stream are arranged. The two parts of the guide element 20 approach each other in the flow direction A, wherein a
Öffnung bzw. ein Abstand 22 zwischen den beiden Teilen gebildet ist. Der Abgasstrom mit der eingespritzten, oxidierbaren Flüssigkeit wird von den Leitelementen 20 in Richtung der Öffnung 22 gelenkt. Die Leitelemente 20 bewirken also ein (in Strömungsrichtung A gesehen) Zusammenströmen des Abgasstromes.Opening or a distance 22 between the two parts is formed. Of the Exhaust gas flow with the injected, oxidizable liquid is directed by the guide elements 20 in the direction of the opening 22. The guide elements 20 thus cause a (seen in the direction of flow A) confluence of the exhaust stream.
Das an der Kurvenaußenseite 18 angeordnete Leitelement 20 (Figuren 4 undThe arranged on the outside of the curve 18 guide element 20 (Figures 4 and
5) besteht aus zwei Teilen, die jeweils in einem stumpfen Winkel ß zur Strömungsrichtung A angeordnet sind. Das Leitelement 20 hat eine gedrehte V- förmige Gestalt. Die beiden Teile des Leitelements 20 treffen sich nämlich in einem Punkt und entfernen sich in Strömungsrichtung A voneinander, wodurch der Abgasstrom von dem Leitelement 20 nach außen zu den Seitenwänden des Rohres gelenkt wird. Da die beiden Teile des Leitelementes 20 sich in einem Punkt treffen, wird die in Tröpfchenform vorliegende Flüssigkeit bei einem Aufprall in kleinere Teile gespalten. Aufgrund der Aufspaltung der Tröpfchen können diese schneller verdampfen. Figur 5 zeigt die Strömungsverhältnisse an der Kurvenaußenseite 18.5) consists of two parts, which are each arranged at an obtuse angle ß to the flow direction A. The guide element 20 has a rotated V-shaped configuration. Namely, the two parts of the guide element 20 meet at a point and move away from each other in the flow direction A, whereby the exhaust gas flow is directed by the guide element 20 outwardly to the side walls of the tube. Since the two parts of the guide element 20 meet at a point, the liquid in droplet form is split in an impact into smaller parts. Due to the splitting of the droplets, they can evaporate faster. FIG. 5 shows the flow conditions on the outside of the curve 18.
Obwohl an der Kurveninnenseite und an der -außenseite 16, 18 nur drei hintereinander angeordnete Leitelemente 20 gezeigt sind, könnten auch mehrere Leitelemente 20, die nicht in einer Flucht liegen, angeordnet sein.Although only three successively arranged guide elements 20 are shown on the inner side of the curve and on the outer side 16, 18, a plurality of guide elements 20 that are not in alignment could also be arranged.
Die Leitelemente 20 können entweder direkt in die Rohrwand geprägt werden oder in einem separaten Metallteil geformt und anschließend beispielsweise durch Schweißen an der Rohrwand befestigt werden.The guide elements 20 can either be embossed directly into the pipe wall or formed in a separate metal part and then attached to the pipe wall, for example by welding.
Durch die Anordnung der Leitelemente 20 werden Verwirbelungen des Abgasstromes erreicht, wie sie in Figur 6 gezeigt sind. Der Abgasstrom mit der eingespritzten Flüssigkeit strömt entlang der Rohrwand (bezüglich Figur 6) nach oben zur Kurvenaußenseite 18. Anschließend strömt der Abgasstrom mittig in Richtung der Kurveninnenseite 16, wobei er von dort wieder entlang der Rohrwand in Richtung der Kurvenaußenseite 18 strömt. Es entstehen zwei Ströme, die jeweils von der Mitte aus zu der jeweiligen seitlichen Rohrwand strömen. Die Geschwindigkeit des Abgasstromes ist insbesondere an der Kurvenaußenseite 18 und im Bereich nahe der Kurvenaußenseite 18 am höchsten. Obwohl in der Beschreibung die eingespritzte Flüssigkeit Harnstoff ist, können die beschriebenen Leitelemente 20 auch bei anderen Flüssigkeiten verwendet werden, die in den Abgasstrom eingebracht werden. The arrangement of the guide elements 20 turbulence of the exhaust gas flow are achieved, as shown in Figure 6. The exhaust gas stream with the injected liquid flows along the pipe wall (with respect to FIG. 6) upwards to the curve outside 18. The exhaust gas flow then flows centrally in the direction of the inside of the curve 16, from where it flows again along the pipe wall in the direction of the curve outside 18. Two streams are created, each of which flows from the center to the respective lateral pipe wall. The speed of the exhaust gas flow is highest, in particular on the outside of the curve 18 and in the region near the outside of the curve 18. Although in the description the injected liquid is urea, the described vanes 20 can also be used with other liquids that are introduced into the exhaust stream.

Claims

Patentansprüche claims
1. Abgasrohr für eine Abgasanlage einer Verbrennungskraftmaschine, mit wenigstens einem Leitelement (20) zur Strömungsbeeinflussung, wobei das Abgasrohr (14) eine Krümmung hat und das Leitelement (20) im Bereich der Krümmung an der Kurveninnenseite (16) und/oder an der Kurvenaußenseite (18) angeordnet ist.1. exhaust pipe for an exhaust system of an internal combustion engine, with at least one guide element (20) for influencing the flow, wherein the exhaust pipe (14) has a curvature and the guide element (20) in the region of curvature on the inside of the curve (16) and / or on the outside of the curve (18) is arranged.
2. Abgasrohr nach Anspruch 1 , dadurch gekennzeichnet, daß das Leitelement (20) an der Kurveninnenseite (16) vorgesehen ist und in einem spitzen Winkel (α) zur Strömungsrichtung (A) angeordnet ist.2. Exhaust pipe according to claim 1, characterized in that the guide element (20) on the inner curve side (16) is provided and at an acute angle (α) to the flow direction (A) is arranged.
3. Abgasrohr nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß das3. Exhaust pipe according to claim 1 or 2, characterized in that the
Leitelement (20) an der Kurvenaußenseite (18) vorgesehen ist und in einem stumpfen Winkel (ß) zur Strömungsrichtung (A) angeordnet ist.Guide element (20) on the outside of the curve (18) is provided and at an obtuse angle (ß) to the flow direction (A) is arranged.
4. Abgasrohr nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Leitelement (20) aus zwei Teilen besteht.4. Exhaust pipe according to one of the preceding claims, characterized in that the guide element (20) consists of two parts.
5. Abgasrohr nach Anspruch 4, dadurch gekennzeichnet, daß sich die beiden Teile des Leitelements (20) an der Kurveninnenseite (16) in Strömungsrichtung (A) aneinander annähern und eine Öffnung (22) zwischen den beiden Teilen gebildet ist.5. Exhaust pipe according to claim 4, characterized in that the two parts of the guide element (20) on the inner curve side (16) in the flow direction (A) approach each other and an opening (22) is formed between the two parts.
6. Abgasrohr nach Anspruch 4 oder Anspruch 5, dadurch gekennzeichnet, daß sich die beiden Teile des Leitelements (20) an der Kurvenaußenseite (18) in6. Exhaust pipe according to claim 4 or claim 5, characterized in that the two parts of the guide element (20) on the outside of the curve (18) in
Strömungsrichtung (A) voneinander entfernen.Remove flow direction (A) from each other.
7. Abgasrohr nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Leitelement (20) in das Abgasrohr (14) geprägt ist.7. Exhaust pipe according to one of the preceding claims, characterized in that the guide element (20) in the exhaust pipe (14) is embossed.
8. Abgasrohr nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß das Leitelement (20) aus einem separaten Metallteil geformt ist. 8. Exhaust pipe according to one of claims 1 to 6, characterized in that the guide element (20) is formed from a separate metal part.
PCT/EP2007/010728 2006-12-18 2007-12-10 Exhaust pipe for an exhaust system of an internal combustion engine WO2008074414A1 (en)

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US10711677B2 (en) 2015-01-22 2020-07-14 Tenneco Automotive Operating Company Inc. Exhaust aftertreatment system having mixer assembly
US10995643B2 (en) 2015-03-09 2021-05-04 Tenneco Gmbh Mixing device
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DE102011083637B4 (en) * 2011-09-28 2016-04-14 Eberspächer Exhaust Technology GmbH & Co. KG Mixing and / or evaporation device
EP2865861B2 (en) 2013-10-22 2019-05-15 Eberspächer Exhaust Technology GmbH & Co. KG Catalyst assembly with injection section

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US11187133B2 (en) 2013-08-05 2021-11-30 Tenneco Gmbh Exhaust system with mixer
US10711677B2 (en) 2015-01-22 2020-07-14 Tenneco Automotive Operating Company Inc. Exhaust aftertreatment system having mixer assembly
US10995643B2 (en) 2015-03-09 2021-05-04 Tenneco Gmbh Mixing device
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