EP0604992A1 - Exhaust device for internal combustion engines - Google Patents

Exhaust device for internal combustion engines Download PDF

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Publication number
EP0604992A1
EP0604992A1 EP93121040A EP93121040A EP0604992A1 EP 0604992 A1 EP0604992 A1 EP 0604992A1 EP 93121040 A EP93121040 A EP 93121040A EP 93121040 A EP93121040 A EP 93121040A EP 0604992 A1 EP0604992 A1 EP 0604992A1
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EP
European Patent Office
Prior art keywords
exhaust gas
gas treatment
flow path
exhaust
section
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP93121040A
Other languages
German (de)
French (fr)
Other versions
EP0604992B1 (en
Inventor
Siegfried Wörner
Rudolf Buhmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eberspaecher Climate Control Systems GmbH and Co KG
Original Assignee
J Eberspaecher GmbH and Co KG
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Publication date
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Publication of EP0604992A1 publication Critical patent/EP0604992A1/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
    • 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
    • F01N13/087—Other arrangements or adaptations of exhaust conduits having valves upstream of silencing apparatus for by-passing at least part of exhaust directly to atmosphere
    • 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
    • F01N13/009—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 having two or more separate purifying devices arranged in series
    • 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
    • F01N13/009—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 having two or more separate purifying devices arranged in series
    • F01N13/0097—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 having two or more separate purifying devices arranged in series the purifying devices are arranged in a single housing
    • 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
    • F01N3/2053—By-passing catalytic reactors, e.g. to prevent overheating
    • 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
    • F01N3/2882—Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices
    • F01N3/2885—Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices with exhaust silencers in a single housing
    • 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
    • F01N1/02—Silencing apparatus characterised by method of silencing by using resonance
    • 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
    • F01N2230/00—Combination of silencers and other devices
    • F01N2230/04—Catalytic converters
    • 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
    • F01N2470/02—Tubes being perforated
    • 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
    • F01N2490/00—Structure, disposition or shape of gas-chambers
    • F01N2490/02—Two or more expansion chambers in series connected by means of tubes
    • F01N2490/06—Two or more expansion chambers in series connected by means of tubes the gases flowing longitudinally from inlet to outlet in opposite directions
    • 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
    • F01N2490/00—Structure, disposition or shape of gas-chambers
    • F01N2490/15—Plurality of resonance or dead chambers
    • F01N2490/155—Plurality of resonance or dead chambers being disposed one after the other in flow direction

Definitions

  • the invention relates to an exhaust system for internal combustion engines, with a main flow path, which has a silencer and - downstream of this in the flow direction - has two catalytically active exhaust gas treatment bodies, characterized in that a bypass flow path is provided for a section of the main flow path, which comprises the silencer and one bypassing the two exhaust treatment bodies and that the section of the main flow path is closable.
  • Catalytic exhaust gas treatment bodies require a certain minimum temperature in order to be able to work properly, which is roughly in the region of 200 to 300 ° C.
  • the exhaust system is constructed in such a way that at least one of the exhaust gas treatment bodies, if possible, after the internal combustion engine is started quickly reaches its required operating temperature.
  • catalytically active exhaust gas treatment bodies cannot tolerate exhaust gas temperatures of any desired level without being damaged. The temperature that is critical for this depends on the structure of the exhaust gas treatment body and on the structure and composition of the actual, catalytically active material, but a rough guide value can be given as 800 to 900 ° C.
  • care should be taken to ensure that the critical temperature on the exhaust gas treatment body (s) is not exceeded even under unfavorable operating conditions, for example prolonged operation of the internal combustion engine under high load.
  • the exhaust system according to the invention solves the technical problem of constructing the exhaust system for internal combustion engines in such a way that a catalytically active exhaust gas treatment body at minimum operating temperature is available as soon as possible after starting the internal combustion engine, but overheating of the exhaust gas treatment body or the exhaust gas treatment body is avoided as reliably as possible.
  • the exhaust system according to the invention makes it possible to let the exhaust gas flow through the bypass flow path after the cold start of the internal combustion engine and thereby to decouple the muffler and one of the two exhaust gas treatment bodies from the direct flow and the associated heating by the exhaust gas. As a result of this decoupling, the material mass of these components is heated up at least substantially less; the heat loss from these components to the environment is drastically reduced.
  • Catalytically active exhaust gas treatment bodies typically consist of a ceramic monolith or a metal flow body, the exhaust gas treatment body having a multiplicity of channels running through it in the flow direction and the inner surfaces being provided with a catalytically active coating.
  • This coating contains the actual catalyst, often particles of certain metals, especially platinum. Excessively high temperatures can damage the catalytic coating.
  • exhaust gas can flow through the section of the main flow path bypassed by the bypass flow path.
  • the exhaust gas emits heat, particularly in the muffler (which in turn heats up and then releases heat to the environment).
  • the temperature of the exhaust gas which flows into the exhaust gas treatment bodies is significantly reduced; the exhaust gas treatment bodies remain significantly cooler, in particular when the internal combustion engine is operated for a prolonged period under high load.
  • the section of the main flow path can be closed at any point in this section.
  • a completely tight seal is not necessary because the invention intended effects can also be achieved if only a small amount of exhaust gas flows through the section of the main flow path.
  • the exhaust system according to the invention can also have more than two exhaust gas treatment bodies. In this case, it is important that at least one exhaust gas treatment body is flowed through when the section of the main flow path is closed. On the other hand, one or more exhaust gas treatment bodies can be decoupled from the direct flow in this state.
  • the muffler and the exhaust gas treatment body have a common housing, as a result of which weight and production outlay can be saved in comparison with an embodiment with separate housings.
  • the two exhaust gas treatment bodies are preferably arranged one after the other in the flow direction; the bypass flow path opens into the space between the first and second exhaust treatment bodies.
  • the two exhaust gas treatment bodies it is alternatively possible to arrange the two exhaust gas treatment bodies in parallel in terms of flow. When the section of the main flow path is closed, exhaust gas flows directly through only one of the two exhaust gas treatment bodies; when the section of the main flow path is open, both exhaust gas treatment bodies are flowed through.
  • the bypass flow path can preferably also be made closable. In this case, the exhaust gas only flows through the described section of the main flow path when the bypass flow path is closed.
  • a particularly compact form of the exhaust system is obtained if the exhaust gas treatment body and silencer are arranged next to one another in a common housing in such a way that the exhaust gas flows in an essentially S-shaped manner during operation.
  • a preferred example of this is given below in the description of an exemplary embodiment. If e.g. is more practical for reasons of space, but you can also arrange the silencer and the exhaust gas treatment body in a common housing one behind the other.
  • the muffler is preferably designed as a 3-chamber reflection muffler. This training offers favorable prerequisites, in particular for the spatial combination with the exhaust gas treatment bodies in a common housing.
  • the silencer can be of any design, e.g. as an absorption silencer.
  • bypass flow path piping can be designed with a cross-section that is 30 to 60% of the flow cross-section of said section of the main flow path.
  • a particularly favorable design results if transverse walls are provided in the common housing of the silencer and exhaust gas treatment bodies and the exhaust gas treatment body and installation pipes of the muffler are supported by these cross walls. In this way, a 3-chamber reflection muffler can also be realized in a particularly favorable design.
  • catalytic exhaust gas treatment bodies are not only used in gasoline-powered internal combustion engines, where they are used in particular as three-way catalysts for oxidizing unburned hydrocarbons and carbon monoxide and for reducing nitrogen oxides, but are also used in exhaust systems for diesel engines, there especially as oxidation catalysts.
  • bypass flow path branch off the main flow path fairly close to the internal combustion engine. This applies particularly to the design with a pipeline of the bypass flow path which is thinner than the pipeline of the section of the main flow path mentioned.
  • the invention has the effect that when the section of the main flow path is closed, the aforementioned muffler is not flowed through, so that the exhaust gas flowing through the bypass flow path is less soundproofed before flowing through the one exhaust gas treatment body. This is usually practically not annoying, because in most cases there is another silencer behind the exhaust system anyway.
  • the invention entails that in that Operating state in which exhaust gas does not flow directly through one of the exhaust gas treatment bodies, overall a shorter exhaust gas treatment body length is available for exhaust gas purification. The resultant, tendency to lower exhaust gas purification effect is more than compensated for by the faster heating of the exhaust gas treatment body through which flow occurs in this operating phase.
  • the invention is also intended to include the case in which there is no silencer in the exhaust line in front of the two exhaust gas treatment bodies.
  • an essential advantage according to the invention is retained, namely that one of the two exhaust gas treatment bodies is decoupled from the direct exhaust gas flow during the operating phase of flowing through the bypass flow path, and thus there is less heat loss to the environment. This is particularly true in the event that the bypass line has a smaller cross section than the mentioned section of the main flow line.
  • the single figure shows in horizontal section an area of an exhaust system designed according to the invention with two exhaust gas treatment bodies and a silencer in a common housing.
  • a housing 2 can be seen which, viewed from the left in the drawing, has an oval or somewhat flattened round cross-section.
  • the housing 2 is produced in that a peripheral wall 4 made of sheet metal is welded to two end walls 6 made of sheet metal. From the left, a first pipe 8 and a second pipe 10 run side by side through the end wall 6 into the interior of the housing. On the right, a third pipeline 12 leads out of the housing 2 through the end wall 6 there.
  • the first pipeline 8 must be imagined to the left beyond the edge of the drawing to the exhaust side of an internal combustion engine (not shown) or to its exhaust manifold, which brings together the exhaust gas flows of the individual cylinders of the internal combustion engine to form a common exhaust pipe.
  • the third pipeline 12 must be thought to the right beyond the drawing margin to the end of the exhaust system of the exhaust system. Between the drawn housing 2 and this exhaust outlet end are in the third Pipeline 12 one or more rear silencers installed.
  • the second pipeline 10 branches off from the first pipeline 8 fairly close to the internal combustion engine or its exhaust manifold.
  • the broken lines 14 indicate that the lengths of the pipes 8 and 10 between the housing 2 and the branch 16 of the second pipe 10 are considerably larger than shown in the drawing. Overall, it is the exhaust system of a motor vehicle.
  • a left, first exhaust gas treatment body 18 and — at an axial distance from it, a second exhaust gas treatment body 20 are held in the housing 2.
  • the two exhaust gas treatment bodies 18 and 20 are cylindrical in the illustrated embodiment and have essentially the same axial length (measured from left to right in the drawing).
  • the two exhaust gas treatment bodies 18 and 20 can also be designed with an unequal axial length, in particular making the second exhaust gas treatment body 20 axially somewhat longer than the first exhaust gas treatment body 18.
  • the two exhaust gas treatment bodies 18 and 20 are each fastened by means of a circumferential mounting mat 22 in a shell 24 made of heat-resistant sheet metal.
  • the shell 24 In the area of the exhaust gas treatment bodies 18, 20, the shell 24 is roughly cylindrical and in the area to the right of it, that is to say downstream, is shaped as a truncated cone. At the smaller diameter end of the truncated cone, the shell 24 merges into the third pipeline 12.
  • the mounting mats 22 consist of sufficiently temperature-resistant fibers. They can also be designed as so-called swelling mats, which contain an addition of mica and thereby increase in volume when heated.
  • the mounting mats 22 serve, on the one hand, for the temperature-resistant, thermal expansion differences between the exhaust gas treatment bodies 18, 20 and the shell 24, to enable quasi-elastic fastening of the exhaust gas treatment bodies 18, 20 in the shell 24. At the same time, the mounting mats 22 prevent external flow around the exhaust gas treatment bodies 18, 20.
  • the shell 24 can be made from two half-shells that are welded together in an axial plane. At the left end, the shell 24 is open, so that exhaust gas can flow in from the left to the left end face of the first exhaust gas treatment body 18.
  • a left, first transverse wall 26 and a right, second transverse wall 28 are fastened in the housing 2 and each run parallel to the end walls 6 of the housing 2.
  • the shell 24 is fastened in two aligned openings of the first transverse wall and the second transverse wall 28.
  • the shell 24 can be double-walled at least in some areas.
  • the first pipeline 8 continues in a straight line inside the housing 2 and forms a first installation pipe 30 of a silencer 32 to be described in more detail later.
  • a second installation tube 34 which runs parallel to the first installation tube 30 and in the axial direction of the housing 2.
  • the installation tubes 30 and 34 are each fastened in two aligned openings of the first transverse wall 26 and the second transverse wall 28.
  • the interior of the housing 2 is divided into three chambers by the transverse walls 26 and 28, namely a left chamber 36, a middle chamber 38 and a right chamber 40 from left to right in the figure.
  • the first installation pipe 30 is both in the left chamber 36 and perforated in the middle chamber 38 and ends openly in the right chamber 40.
  • the second installation tube 34 is perforated in the middle chamber 38 and has an open end in both the left chamber 36 and the right chamber 40. In this way, a 3-chamber reflection silencer 32 is formed.
  • the main flow of the exhaust gas flowing through the first pipeline 8 goes through the first installation pipe 30 into the right-hand chamber 40 and from there, so to speak, backwards through the second installation pipe 34 into the left-hand chamber 36, with additional quantities escaping through the perforations described as a result of the exhaust-gas pressure pulsations and enter.
  • the left, open end 42 of the shell 24 described further above lies in the left chamber 36, so that the exhaust gas after passing through the muffler 32 can flow from there through the two exhaust gas treatment bodies 18, 20 and finally flow out through the third pipeline 12. Overall, this results in an essentially S-shaped or meandering course of the flow of the exhaust gas through the housing 2.
  • the second pipeline 10 is initially continued in a straight line inside the housing 2 and leads through a fastening opening in the first transverse wall 26. Behind it, the pipeline bends approximately at right angles and leads through an opening in the shell 24 into the space 44 between the axially spaced exhaust gas treatment bodies 18 , 20th
  • a first flap 46 is arranged in the first pipeline 8.
  • the first flap 46 can be pivoted between an open position, in which it lies essentially parallel to the flow direction of the exhaust gas, and a closed position, in which it is essentially perpendicular to the exhaust gas flow direction. In order to illustrate this, an intermediate position is drawn in the drawing.
  • a second flap 48 is arranged in the second pipeline 10. The second flap 48 can be pivoted between an open position and a closed position, analogously to that described for the first flap 46.
  • the described exhaust system without the branch 16 and the second pipeline 10 including its continuation up to the space 44 between the two exhaust gas treatment bodies 18, 20, you have a main flow path of the exhaust system in front of you, formed by the first pipeline 8, the one before described flow path area through the muffler 32, the subsequent flow path area first through the first exhaust treatment body 18, then through the space 44, then through the second exhaust treatment body 20, and finally through the third pipeline 12, usually with rear silencer, to the outlet end.
  • the second pipeline 10 including its continuation within the housing 2 to the space 44 between the two exhaust gas treatment bodies 18, 20, forms a bypass flow path.
  • the section of the main flow path described above bridged by the bypass flow path thus extends from the branch 16 to the space 44.
  • the first flap 46 When the internal combustion engine, to which the described exhaust system belongs, is started in the cold state or in the non-operating state, the first flap 46 is in its closed position and the second flap 48 is in its open position. Except for this, the exhaust gas flows of a smaller leakage flow past the first flap 46 despite its closed position, exclusively through the second pipeline 10 or the bypass flow path.
  • the exhaust gas bypasses the muffler 32 and the first exhaust gas treatment body 18. It flows through the second exhaust gas treatment body 20, where the gaseous pollutants contained are at least largely made harmless, as mentioned in the introduction to the description. Since the exhaust gas flows in the most direct way to the second exhaust gas treatment body 20, the latter is optimally heated to its desired minimum working temperature.
  • the second pipeline 10 has a significantly smaller diameter than the first pipeline 8, so that the heat-emitting surface of the second pipeline 10 is significantly smaller than the surface of the first pipeline 8 that emits heat when flowing through, which further reduces the heat losses brings the exhaust gas to the environment.
  • the shell 24 is spaced on all sides to the peripheral wall 4 of the housing 2, so that with the exception of heat conduction through the transverse walls 26, 28 the heat losses from the shell 24 to the environment are very low.
  • the first flap 46 is opened and the second flap 48 is closed. Now all of the exhaust gas - with the exception of a certain amount of leakage flow past the closed second flap 48 - flows through the section of the main flow path described further above as if the bypass flow path were not present. Now the muffler 32 comes into full operation, the two exhaust gas treatment bodies 18, 20 are flowed through in succession with the result of optimal pollutant reduction. The first exhaust gas treatment body 18 now also heats up rapidly.
  • the two exhaust gas treatment bodies 18, 20 do not necessarily have to be arranged one after the other in the flow direction, as is the case in the exemplary embodiment described. Instead, the exhaust gas treatment bodies 18, 20 can be arranged in parallel in terms of flow, for example one above the other in the drawing figure.
  • the second pipeline 10 can open into the space in front of the two exhaust gas treatment bodies 18, 20 of the left chamber 36.
  • a flap would have to be provided in one of these two exhaust gas ducts. If this flap is closed, the exhaust gas treatment body associated with this exhaust gas duct is not directly flowed through.
  • a temperature sensor arranged, for example, behind the second exhaust gas treatment body 20 can be provided. If the temperature detected by this temperature sensor is a little above the minimum working temperature of the exhaust gas treatment body, the second exhaust gas treatment body 20 has certainly reached its minimum working temperature. A corresponding signal is sent to a control unit, which then triggers the flaps 46, 48 to be changed over by means of suitable drives.

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

Abstract

Exhaust system for internal combustion engines with a main flow line, which has a silencer (32) and - arranged downstream of this - two catalytically acting exhaust treatment bodies (18, 20), characterised in that a bypass flow line (10) for a section (8, 30, 40, 34, 36, 18) of the main flow line is provided, which bypasses the silencer (32) and one of the two exhaust treatment bodies (18, 20); and in that the section (8, 30, 40, 34, 36, 18) of the main flow line is closable. <IMAGE>

Description

Gegenstand der Erfindung ist eine Abgasanlage für Verbrennungsmotoren, mit einen Hauptströmungsweg, der einen Schalldämpfer und - in Strömungsrichtung diesem nachgeordnet - zwei katalytisch wirkende Abgasbehandlungskörper aufweist, dadurch gekennzeichnet, daß ein Bypass-Strömungsweg für einen Ahchnitt des Hauptströmungswegs vorgesehen ist, der den Schalldämpfer und einen der zwei Abgasbehandlungskörper umgeht, und daß der Abschnitt des Hauptströmungswegs schließbar ist.The invention relates to an exhaust system for internal combustion engines, with a main flow path, which has a silencer and - downstream of this in the flow direction - has two catalytically active exhaust gas treatment bodies, characterized in that a bypass flow path is provided for a section of the main flow path, which comprises the silencer and one bypassing the two exhaust treatment bodies and that the section of the main flow path is closable.

Moderne Abgasanlagen für Verbrennungsmotoren weisen außer mindestens einem Schalldämpfer häufig einen oder mehrere katalytisch wirkende Abgasbehandlungskörper auf. Bei derartigen Abgasanlagen hat man bereits daran gedacht, einen Schalldämpfer stromaufwärts im Abgasstrang vor einem katalytisch wirkenden Abgasbehandlungskörper vorzusehen. Es ist bereits bekannt, im Abgasstrang zwei katalytisch wirkende Abgasbehandlungskörper in relativ geringem Abstand hintereinander anzuordnen.In addition to at least one silencer, modern exhaust systems for internal combustion engines often have one or more catalytically active exhaust gas treatment bodies. In such exhaust systems, it has already been considered to provide a silencer upstream in the exhaust line in front of a catalytically active exhaust gas treatment body. It is already known to arrange two catalytically active exhaust gas treatment bodies one behind the other at a relatively short distance in the exhaust line.

Katalytisch wirkende Abgasbehandlungskörper benötigen, um ordnungsgemäß arbeiten zu können, eine gewisse Mindesttemperatur, die - grob gesprochenin der Gegend von 200 bis 300°C liegt. Insofern ist es günstig, wenn die Abgasanlage so konstruiert ist, daß nach dem Starten des Verbrennungsmotors mindestens einer der Abgasbehandlungskörper möglichst rasch auf seine erforderliche Betriebstemperatur kommt. Andererseits vertragen katalytisch wirkende Abgasbehandlungskörper nicht beliebig hohe Abgastemperaturen, ohne Schaden zu nehmen. Die hierfür kritische Temperatur hängt vom Aufbau des Abgasbehandlungskörpers und vom Aufbau und der Zusammensetzung des eigentlichen, katalytisch wirkenden Materials ab, aber als groben Richtwert kann man 800 bis 900°C angeben. Infolgedessen sollte man bei der Konstruktion einer Abgasanlage darauf achten, daß die kritische Temperatur an dem (den) Abgasbehandlungskörper(n) auch unter ungünstigen Betriebsbedingungen, z.B. längerem Betrieb des Verbrennungsmotors mit hoher Last, nicht überschritten wird.Catalytic exhaust gas treatment bodies require a certain minimum temperature in order to be able to work properly, which is roughly in the region of 200 to 300 ° C. In this respect, it is expedient if the exhaust system is constructed in such a way that at least one of the exhaust gas treatment bodies, if possible, after the internal combustion engine is started quickly reaches its required operating temperature. On the other hand, catalytically active exhaust gas treatment bodies cannot tolerate exhaust gas temperatures of any desired level without being damaged. The temperature that is critical for this depends on the structure of the exhaust gas treatment body and on the structure and composition of the actual, catalytically active material, but a rough guide value can be given as 800 to 900 ° C. As a result, when designing an exhaust system, care should be taken to ensure that the critical temperature on the exhaust gas treatment body (s) is not exceeded even under unfavorable operating conditions, for example prolonged operation of the internal combustion engine under high load.

Die erfindungsgemäße Abgasanlage löst das technische Problem, die Abgasanlage für Verbrennungsmotoren derart aufzubauen, daß möglichst rasch nach dem Starten des Verbrennungsmotors ein katalytisch wirkender Abgasbehandlungskörper auf Mindestbetriebstemperatur zur Verfügung steht, aber Überhitzungen des Abgasbehandlungskörpers bzw. der Abgasbehandlungskörper möglichst zuverlässig vermieden werden.The exhaust system according to the invention solves the technical problem of constructing the exhaust system for internal combustion engines in such a way that a catalytically active exhaust gas treatment body at minimum operating temperature is available as soon as possible after starting the internal combustion engine, but overheating of the exhaust gas treatment body or the exhaust gas treatment body is avoided as reliably as possible.

Die erfindungsgemäße Abgasanlage ermöglicht es, nach dem Kaltstart des Verbrennungsmotors das Abgas durch den Bypass-Strömungsweg strömen zu lassen und dadurch den Schalldämpfer und einen der zwei Abgasbehandlungskörper von der unmittelbaren Durchströmung und damit zusammenhängender Aufheizung durch das Abgas abzukoppeln. Infolge dieser Abkopplung wird die Materialmasse dieser Bauteile zumindest wesentlich weniger stark aufgeheizt; die Wärmeabgabeverluste von diesen Bauteilen an die Umgebung sind drastisch reduziert.The exhaust system according to the invention makes it possible to let the exhaust gas flow through the bypass flow path after the cold start of the internal combustion engine and thereby to decouple the muffler and one of the two exhaust gas treatment bodies from the direct flow and the associated heating by the exhaust gas. As a result of this decoupling, the material mass of these components is heated up at least substantially less; the heat loss from these components to the environment is drastically reduced.

Aus der weiteren Beschreibung wird deutlich werden, daß die Abkopplung der genannten Bauteile vom Abgasstrom keineswegs perfekt sein muß. Eine erhebliche Reduzierung der Beaufschlagung dieser Bauteile mit Abgas reicht aus, die erfindugsgemäß beabsichtigten Wirkungen zu erreichen.From the further description it will be clear that the decoupling of the components mentioned from the exhaust gas flow need not be perfect. A considerable reduction in the exposure of these components to exhaust gas is sufficient to achieve the effects intended according to the invention.

Katalytisch wirkende Abgasbehandlungskörper bestehen typischerweise aus einem keramischen Monolithen oder einem metallischen Durchströmungskörper, wobei der Abgasbehandlungskörper eine Vielzahl von ihn in Strömungsrichtung durchziehenden Kanälen aufweist und wobei die inneren Oberflächen mit einer katalytisch wirkenden Beschichtung versehen sind. Diese Beschichtung enthält den eigentlichen Katalysator, häufig Partikel bestimmter Metalle, insbesondere Platin. Übermäßig hohe Temperaturen können die katalytische Beschichtung schädigen.Catalytically active exhaust gas treatment bodies typically consist of a ceramic monolith or a metal flow body, the exhaust gas treatment body having a multiplicity of channels running through it in the flow direction and the inner surfaces being provided with a catalytically active coating. This coating contains the actual catalyst, often particles of certain metals, especially platinum. Excessively high temperatures can damage the catalytic coating.

Nachdem der anfangs vom Abgas durchströmte Abgasbehandlungskörper eine genügend hohe Temperatur erreicht hat, kann Abgas durch den vom Bypass-Strömungsweg umgangenen Abschnitt des Hauptströmungswegs strömen. Dort gibt das Abgas insbesondere im Schalldämpfer (der sich seinerseits aufheizt und dann Wärme an die Umgebung abgibt) Wärme ab. Hierdurch wird die Temperatur des Abgases, welches den Abgasbehandlungskörpern zuströmt, entscheidend gesenkt; die Abgasbehandlungskörper bleiben insbesondere bei längerdauerndem Betrieb des Verbrennungsmotors mit hoher Last entscheidend kühler.After the exhaust gas treatment body initially flowed through by the exhaust gas has reached a sufficiently high temperature, exhaust gas can flow through the section of the main flow path bypassed by the bypass flow path. There, the exhaust gas emits heat, particularly in the muffler (which in turn heats up and then releases heat to the environment). As a result, the temperature of the exhaust gas which flows into the exhaust gas treatment bodies is significantly reduced; the exhaust gas treatment bodies remain significantly cooler, in particular when the internal combustion engine is operated for a prolonged period under high load.

Das Schließen des Abschnitts des Hauptströmungswegs kann an im Prinzip beliebiger Stelle dieses Abschnitts erfolgen. Ein völlig dichtes Abschließen ist nicht erforderlich, da die erfindungsgemäß beabsichtigten Effekte auch erreicht werden, wenn der Abschnitt des Hauptströmungswegs nur von einer geringen Abgas-Teilmenge durchströmt wird.In principle, the section of the main flow path can be closed at any point in this section. A completely tight seal is not necessary because the invention intended effects can also be achieved if only a small amount of exhaust gas flows through the section of the main flow path.

Es wird darauf hingewiesen, daß die erfindungsgemäße Abgasanlage auch mehr als zwei Abgasbehandlungskörper aufweisen kann. In diesem Fall kommt es darauf an, daß bei geschlossenem Abschnitt des Hauptströmungswegs mindestens noch ein Abgasbehandlungskörper durchströmt wird. Andererseits können in diesem Zustand ein oder mehrere Abgasbehandlungskörper von der unmittelbaren Durchströmung abgekoppelt werden.It is pointed out that the exhaust system according to the invention can also have more than two exhaust gas treatment bodies. In this case, it is important that at least one exhaust gas treatment body is flowed through when the section of the main flow path is closed. On the other hand, one or more exhaust gas treatment bodies can be decoupled from the direct flow in this state.

In bevorzugter Weiterbildung der Erfindung besitzen der Schalldämpfer und die Abgasbehandlungskörper ein gemeinsames Gehäuse, wodurch im Vergleich zu einer Ausführung mit getrennten Gehäusen Gewicht und Fertigungsaufwand gespart werden können.In a preferred development of the invention, the muffler and the exhaust gas treatment body have a common housing, as a result of which weight and production outlay can be saved in comparison with an embodiment with separate housings.

Vorzugsweise sind die beiden Abgasbehandlungskörper in Strömungsrichtung nacheinander angeordnet; der Bypass-Strömungweg mündet in den Raum zwischen dem ersten und dem zweiten Abgasbehandlungskörper. Es ist jedoch alternativ möglich, die beiden Abgasbehandlungskörper strömungsmäßig parallel anzuordnen. Bei geschlossenem Abschnitt des Hauptströmungswegs wird nur einer der beiden Abgasbehandlungskörper von Abgas unmittelbar durchströmt, bei geöffnetem Abschnitt des Hauptströmungswegs werden beide Abgasbehandlungskörper durchströmt.The two exhaust gas treatment bodies are preferably arranged one after the other in the flow direction; the bypass flow path opens into the space between the first and second exhaust treatment bodies. However, it is alternatively possible to arrange the two exhaust gas treatment bodies in parallel in terms of flow. When the section of the main flow path is closed, exhaust gas flows directly through only one of the two exhaust gas treatment bodies; when the section of the main flow path is open, both exhaust gas treatment bodies are flowed through.

Man kann vorzugsweise auch den Bypass-Strömungsweg schließbar ausführen. In diesem Fall strömt das Abgas bei geschlossenem Bypass-Strömungsweg nur durch den geschilderten Abschnitt des Hauptströmungswegs.The bypass flow path can preferably also be made closable. In this case, the exhaust gas only flows through the described section of the main flow path when the bypass flow path is closed.

Eine besonders kompakte Form der Abgasanlage erhält man, wenn Abgasbehandlungskörper und Schalldämpfer in einem gemeinsamen Gehäuse so nebeneinander angeordnet werden, daß das Abgas im Betrieb im wesentlichen S-förmig strömt. Ein bevorzugtes Beispiel hierfür wird weiter unten bei der Beschreibung eines Ausführungsbeispiels gegeben. Wenn es z.B. aus Platzgründen praktischer ist, kann man jedoch auch den Schalldämpfer und die Abgasbehandlungskörper in einem gemeinsamen Gehäuse hintereinander anordnen.A particularly compact form of the exhaust system is obtained if the exhaust gas treatment body and silencer are arranged next to one another in a common housing in such a way that the exhaust gas flows in an essentially S-shaped manner during operation. A preferred example of this is given below in the description of an exemplary embodiment. If e.g. is more practical for reasons of space, but you can also arrange the silencer and the exhaust gas treatment body in a common housing one behind the other.

Vorzugsweise ist der Schalldämpfer als 3-Kammer-Reflexionsschalldämpfer ausgebildet. Diese Ausbildung bietet günstige Vorraussetzungen insbesondere für das räumliche Zusammenfassen mit den Abgasbehandlungskörpern in einem gemeinsamen Gehäuse. Prinzipiell kann man jedoch den Schalldämpfer in beliebiger Bauart ausführen, z.B. als Absorptionsschalldämpfer.The muffler is preferably designed as a 3-chamber reflection muffler. This training offers favorable prerequisites, in particular for the spatial combination with the exhaust gas treatment bodies in a common housing. In principle, however, the silencer can be of any design, e.g. as an absorption silencer.

In weiterer Ausgestaltung der Erfindung ist es bevorzugt, den Bypass-Strömungsweg mit eineminsgesamt gesehen - geringeren Strömungsquerschnitt zu gestalten als den weiter vorn angesprochenen Abschnitt des Hauptströmungswegs. Dahinter steht der Gedanke, die wärmeabgebende Oberfläche des Bypass-Strömungswegs möglichst klein zu halten, soweit dies mit den Abgas-Strömungsverhältnissen verträglich ist. Für praktische Ausführungen kann man insbesondere die Rohrleitung des Bypass-Strömungswegs mit einem Querschnitt ausführen, der 30 bis 60 % des Strömungsquerschnitts des genannten Abschnitts des Hauptströmungswegs beträgt.In a further embodiment of the invention, it is preferred to design the bypass flow path with an overall smaller flow cross section than the section of the main flow path mentioned further above. The idea behind this is to keep the heat-emitting surface of the bypass flow path as small as possible, insofar as this is compatible with the exhaust gas flow conditions. For practical implementations, in particular the bypass flow path piping can be designed with a cross-section that is 30 to 60% of the flow cross-section of said section of the main flow path.

Eine besonders günstige Ausführung ergibt sich, wenn man in dem gemeinsamen Gehäuse von Schalldämpfer und Abgasbehandlungskörpern Querwände vorsieht und die Abgasbehandlungskörper sowie Einbaurohre des Schalldämpfers durch diese Querwände abstützt. Auf diese Weise läßt sich auch konstruktiv besonders günstig ein 3-Kammer-Reflexions-Schalldämpfer verwirklichen.A particularly favorable design results if transverse walls are provided in the common housing of the silencer and exhaust gas treatment bodies and the exhaust gas treatment body and installation pipes of the muffler are supported by these cross walls. In this way, a 3-chamber reflection muffler can also be realized in a particularly favorable design.

Es wird darauf hingewiesen, daß katalytisch wirkende Abgasbehandlungskörper nicht nur bei benzinbetriebenen Verbrennungsmotoren eingesetzt werden, wo sie insbesondere als Dreiwege-Katalysatoren für ein Oxidieren unverbrannter Kohlenwasserstoffe und von Kohlenmonoxid sowie für ein Reduzieren von Stickoxiden sorgen, sondern auch bei Abgasanlagen für Dieselmotoren eingesetzt werden, dort insbesondere als Oxidationskatalysatoren.It is pointed out that catalytic exhaust gas treatment bodies are not only used in gasoline-powered internal combustion engines, where they are used in particular as three-way catalysts for oxidizing unburned hydrocarbons and carbon monoxide and for reducing nitrogen oxides, but are also used in exhaust systems for diesel engines, there especially as oxidation catalysts.

Generell gesehen ist es günstig, den Bypass-Strömungsweg ziemlich dicht am Verbrennungsmotor vom Hauptströmungsweg abzweigen zu lassen. Dies gilt ganz besonders für die Ausführung mit einer Rohrleitung des Bypass-Strömungswegs, die dünner als die Rohrleitung des genannten Abschnitts des Hauptströmungswegs ist.Generally speaking, it is favorable to have the bypass flow path branch off the main flow path fairly close to the internal combustion engine. This applies particularly to the design with a pipeline of the bypass flow path which is thinner than the pipeline of the section of the main flow path mentioned.

Die Erfindung bringt den Effekt mit sich, daß bei geschlossenem Abschnitt des Hauptströmungswegs der genannte Schalldämpfer nicht durchströmt wird, so daß das durch den Bypass-Strömungsweg strömende Abgas vor dem Durchströmen des einen Abgasbehandlungskörpers weniger schallgedämpft wird. Dies ist normalerweise praktisch nicht störend, weil weiter hinten im Abgasstrang in den meisten Fällen sowieso noch ein weiterer Schalldämpfer sitzt. Außerdem bringt die Erfindung mit sich, daß in demjenigen Betriebszustand, in dem einer der Abgasbehandlungskörper nicht unmittelbar von Abgas durchströmt wird, insgesamt eine geringere Abgasbehandlungskörperlänge zur Abgasreinigung zur Verfügung steht. Die hieraus resultierende, tendenziell geringere Abgasreinigungswirkung wird jedoch mehr als kompensiert durch die erreichte raschere Aufheizung des in dieser Betriebsphase durchströmten Abgasbehandlungskörpers.The invention has the effect that when the section of the main flow path is closed, the aforementioned muffler is not flowed through, so that the exhaust gas flowing through the bypass flow path is less soundproofed before flowing through the one exhaust gas treatment body. This is usually practically not annoying, because in most cases there is another silencer behind the exhaust system anyway. In addition, the invention entails that in that Operating state in which exhaust gas does not flow directly through one of the exhaust gas treatment bodies, overall a shorter exhaust gas treatment body length is available for exhaust gas purification. The resultant, tendency to lower exhaust gas purification effect is more than compensated for by the faster heating of the exhaust gas treatment body through which flow occurs in this operating phase.

Schließlich wird darauf aufmerksam gemacht, daß die Erfindung auch denjenigen Fall umfassen soll, daß im Abgasstrang vor den beiden Abgasbehandlungskörpern kein Schalldämpfer vorhanden ist. Auch in diesem Fall bleibt ein wesentlicher, erfindungsgemäßer Vorteil erhalten, daß nämlich einer der beiden Abgasbehandlungskörper bei der Betriebsphase des Durchströmens des Bypass-Strömungswegs von der unmittelbaren Abgasdurchströmung abgekoppelt ist und damit dort geringere Wärmeverluste an die Umgebung auftreten. Dies gilt ganz besonders für den Fall, daß die Bypass-Leitung einen kleineren Querschnitt als der genannte Abschnitt der Hauptströmungsleitung hat.Finally, attention is drawn to the fact that the invention is also intended to include the case in which there is no silencer in the exhaust line in front of the two exhaust gas treatment bodies. In this case, too, an essential advantage according to the invention is retained, namely that one of the two exhaust gas treatment bodies is decoupled from the direct exhaust gas flow during the operating phase of flowing through the bypass flow path, and thus there is less heat loss to the environment. This is particularly true in the event that the bypass line has a smaller cross section than the mentioned section of the main flow line.

Die Erfindung und Weiterbildungen der Erfindung werden nachfolgend anhand eines zeichnerisch dargestellten Ausführungsbeispiels näher erläutert.The invention and further developments of the invention are explained in more detail below with reference to an exemplary embodiment shown in the drawing.

Die einzige Figur zeigt im Horizontalschnitt einen erfindungsgemäß ausgebildeten Bereich einer Abgasanlage mit zwei Abgasbehandlungskörpern und einem Schalldämpfer in einem gemeinsamen Gehäuse.The single figure shows in horizontal section an area of an exhaust system designed according to the invention with two exhaust gas treatment bodies and a silencer in a common housing.

In der Zeichnungsfigur erkennt man ein Gehäuse 2, welches - von links in der Zeichnung betrachteteinen ovalen oder etwas flachgedrückt-runden Querschnitt hat. Das Gehäuse 2 ist dadurch hergestellt, daß eine Umfangswand 4 aus Blech mit zwei Stirnwänden 6 aus Blech verschweißt ist. Von links führen nebeneinander eine erste Rohrleitung 8 und eine zweite Rohrleitung 10 durch die dortige Stirnwand 6 in das Innere des Gehäuses hinein. Rechts führt eine dritte Rohrleitung 12 durch die dortige Stirnwand 6 aus dem Gehäuse 2 heraus.In the drawing figure a housing 2 can be seen which, viewed from the left in the drawing, has an oval or somewhat flattened round cross-section. The housing 2 is produced in that a peripheral wall 4 made of sheet metal is welded to two end walls 6 made of sheet metal. From the left, a first pipe 8 and a second pipe 10 run side by side through the end wall 6 into the interior of the housing. On the right, a third pipeline 12 leads out of the housing 2 through the end wall 6 there.

Die erste Rohrleitung 8 muß man sich nach links über den Zeichnungsrand hinaus fortgesetzt vorstellen bis zur Abgasseite eines nicht eingezeichneten Verbrennungsmotors bzw. bis zu dessen Abgaskrümmer, der die Abgasströme der einzelnen Zylinder des Verbrennungsmotors zu einem gemeinsamen Abgasrohr zusammenführt. Die dritte Rohrleitung 12 muß man sich nach rechts über den Zeichnungsrand hinaus fortgesetzt denken bis zum Abgasaustrittsende der Abgasanlage. Zwischen dem gezeichneten Gehäuse 2 und diesem Abgasaustrittsende sind in die dritte Rohrleitung 12 ein oder mehrere Nachschalldämpfer eingebaut. Die zweite Rohrleitung 10 zweigt von der ersten Rohrleitung 8 ziemlich dicht am Verbrennungsmotor bzw. dessen Abgaskrümmer ab. Durch die Unterbrechungslinien 14 ist angedeutet, daß die Längen der Rohrleitungen 8 und 10 zwischen dem Gehäuse 2 und der Abzweigung 16 der zweiten Rohrleitung 10 beträchtlich größer sind als zeichnerisch dargestellt. Insgesamt handelt es sich um die Abgasanlage eines Kraftfahrzeugs.The first pipeline 8 must be imagined to the left beyond the edge of the drawing to the exhaust side of an internal combustion engine (not shown) or to its exhaust manifold, which brings together the exhaust gas flows of the individual cylinders of the internal combustion engine to form a common exhaust pipe. The third pipeline 12 must be thought to the right beyond the drawing margin to the end of the exhaust system of the exhaust system. Between the drawn housing 2 and this exhaust outlet end are in the third Pipeline 12 one or more rear silencers installed. The second pipeline 10 branches off from the first pipeline 8 fairly close to the internal combustion engine or its exhaust manifold. The broken lines 14 indicate that the lengths of the pipes 8 and 10 between the housing 2 and the branch 16 of the second pipe 10 are considerably larger than shown in the drawing. Overall, it is the exhaust system of a motor vehicle.

Oben in der Zeichnungsfigur sind in dem Gehäuse 2 ein linker, erster Abgasbehandlugskörper 18 und-mit axialem Abstand zu diesem, ein zweiter Abgasbehandlungskörper 20 gehaltert. Die beiden Abgasbehandlungskörper 18 und 20 sind beim gezeichneten Ausführungsbeispiel zylindrisch und haben im wesentlichen gleiche axiale Länge (gemessen von links nach rechts in der Zeichnung). Man kann jedoch die beiden Abgasbehandlungskörper 18 und 20 auch mit ungleicher axialer Länge ausbilden, insbesondere den zweiten Abgasbehandlungskörper 20 axial etwas länger als den ersten Abgasbehandlungskörper 18 machen.At the top of the drawing figure, a left, first exhaust gas treatment body 18 and — at an axial distance from it, a second exhaust gas treatment body 20 are held in the housing 2. The two exhaust gas treatment bodies 18 and 20 are cylindrical in the illustrated embodiment and have essentially the same axial length (measured from left to right in the drawing). However, the two exhaust gas treatment bodies 18 and 20 can also be designed with an unequal axial length, in particular making the second exhaust gas treatment body 20 axially somewhat longer than the first exhaust gas treatment body 18.

Die beiden Abgasbehandlungskörper 18 und 20 sind jeweils mittels einer umlaufenden Halterungsmatte 22 in einer Schale 24 aus warmfestem Blech befestigt. Die Schale 24 ist im Bereich der Abgasbehandlungskörper 18, 20 - ganz grob gesprochenzylindrisch gestaltet und im Bereich rechts davon, also stromabwärts, kegelstumpfförmig-verjüngend gestaltet. Am durchmesserkleineren Ende des Kegelstumpfes geht die Schale 24 in die dritte Rohrleitung 12 über.The two exhaust gas treatment bodies 18 and 20 are each fastened by means of a circumferential mounting mat 22 in a shell 24 made of heat-resistant sheet metal. In the area of the exhaust gas treatment bodies 18, 20, the shell 24 is roughly cylindrical and in the area to the right of it, that is to say downstream, is shaped as a truncated cone. At the smaller diameter end of the truncated cone, the shell 24 merges into the third pipeline 12.

Die Halterungsmatten 22 bestehen aus hinreichend temperaturfesten Fasern. Sie können auch als sogenannte Quellmatten ausgeführt sein, die einen Zusatz an Glimmer enthalten und dadurch bei Erwärmung an Volumen zunehmen. Die Halterungsmatten 22 dienen einerseits der temperaturbeständigen, Wärmedehnungsunterschiede zwischen den Abgasbehandlungskörpern 18, 20 sowie der Schale 24 ermöglichenden, quasi-elastischen Befestigung der Abgasbehandlungskörper 18, 20 in der Schale 24. Zugleich verhindern die Halterungsmatten 22 eine äußere Umströmung der Abgasbehandlungskörper 18, 20.The mounting mats 22 consist of sufficiently temperature-resistant fibers. They can also be designed as so-called swelling mats, which contain an addition of mica and thereby increase in volume when heated. The mounting mats 22 serve, on the one hand, for the temperature-resistant, thermal expansion differences between the exhaust gas treatment bodies 18, 20 and the shell 24, to enable quasi-elastic fastening of the exhaust gas treatment bodies 18, 20 in the shell 24. At the same time, the mounting mats 22 prevent external flow around the exhaust gas treatment bodies 18, 20.

Links von dem ersten Abgasbehandlungskörper 18, zwischen den beiden Abgasbehandlungskörpern 18, 20, und rechts von dem zweiten Abgasbehandlungskörper 20 ist die Schale 24 so weit in ihrem Durchmesser reduziert, daß die Halterungsmatten 22 gegen Axialbewegung gesichert aufgenommen sind. Außerdem bilden die Schultern eine Sicherung gegen übermäßige axiale Bewegung der Abgasbehandlungskörper 18, 20, falls die halternde Anpreßkraft der Halterungsmatten 22 einmal nicht ausreicht. Die Schale 24 kann aus zwei Halbschalen hergestellt sein, die in einer Axialebene miteinander verschweißt sind. Am linken Ende ist die Schale 24 offen, so daß dort von links her Abgas zur linken Stirnseite des ersten Abgasbehandlungskörpers 18 zuströmen kann.To the left of the first exhaust gas treatment body 18, between the two exhaust gas treatment bodies 18, 20, and to the right of the second exhaust gas treatment body 20, the diameter of the shell 24 is reduced to such an extent that the mounting mats 22 are securely received against axial movement. In addition, the shoulders form a safeguard against excessive axial movement of the exhaust gas treatment bodies 18, 20 if the holding contact pressure of the holding mats 22 is insufficient once. The shell 24 can be made from two half-shells that are welded together in an axial plane. At the left end, the shell 24 is open, so that exhaust gas can flow in from the left to the left end face of the first exhaust gas treatment body 18.

In dem Gehäuse 2 sind eine linke, erste Querwand 26 und eine rechte, zweite Querwand 28 befestigt, die jeweils parallel zu den Stirnwänden 6 des Gehäuses 2 verlaufen. Die Schale 24 ist in zwei fluchtenden Öffnungen der ersten Querwand und der zweiten Querwand 28 befestigt.A left, first transverse wall 26 and a right, second transverse wall 28 are fastened in the housing 2 and each run parallel to the end walls 6 of the housing 2. The shell 24 is fastened in two aligned openings of the first transverse wall and the second transverse wall 28.

Es wird darauf hingewiesen, daß man die Schale 24 alternativ zumindest bereichsweise doppelwandig ausbilden kann.It is pointed out that, alternatively, the shell 24 can be double-walled at least in some areas.

Unten in der Zeichnung erkennt man, daß die erste Rohrleitung 8 im Inneren des Gehäuses 2 geradlinig fortgesetzt ist und dort ein erstes Einbaurohr 30 eines später kompletter zu beschreibenden Schalldämpfers 32 bildet. In der Zeichnung unterhalb des ersten Einbaurohrs 30 befindet sich ein zweites Einbaurohr 34, welches parallel zu dem ersten Einbaurohr 30 und in Axialrichtung des Gehäuses 2 verläuft. Die Einbaurohre 30 und 34 sind jeweils in zwei miteinander fluchtenden Öffnungen der ersten Querwand 26 und der zweiten Querwand 28 befestigt.At the bottom of the drawing it can be seen that the first pipeline 8 continues in a straight line inside the housing 2 and forms a first installation pipe 30 of a silencer 32 to be described in more detail later. In the drawing, below the first installation tube 30 there is a second installation tube 34 which runs parallel to the first installation tube 30 and in the axial direction of the housing 2. The installation tubes 30 and 34 are each fastened in two aligned openings of the first transverse wall 26 and the second transverse wall 28.

Durch die Querwände 26 und 28 ist das Innere des Gehäuses 2 in drei Kammern unterteilt, nämlich von links nach rechts in der Figur eine linke Kammer 36, eine mittlere Kammer 38 und eine rechte Kammer 40. Das erste Einbaurohr 30 ist sowohl in der linken Kammer 36 als auch in der mittleren Kammer 38 perforiert und endet offen in der rechten Kammer 40. Das zweite Einbaurohr 34 ist in der mittleren Kammer 38 perforiert und hat sowohl in der linken Kammer 36 als auch in der rechten Kammer 40 jeweils ein offenes Ende. Auf diese Weise ist ein 3-Kammer-Reflexionsschalldämpfer 32 gebildet. Die Hauptströmung des durch die erste Rohrleitung 8 strömenden Abgases geht durch das erste Einbaurohr 30 in die rechte Kammer 40 und von dort sozusagen rückwärts durch das zweite Einbaurohr 34 in die linke Kammer 36, wobei infolge der Abgas-Druckpulsationen zusätzlich Teilmengen durch die beschriebenen Perforationen austreten und eintreten.The interior of the housing 2 is divided into three chambers by the transverse walls 26 and 28, namely a left chamber 36, a middle chamber 38 and a right chamber 40 from left to right in the figure. The first installation pipe 30 is both in the left chamber 36 and perforated in the middle chamber 38 and ends openly in the right chamber 40. The second installation tube 34 is perforated in the middle chamber 38 and has an open end in both the left chamber 36 and the right chamber 40. In this way, a 3-chamber reflection silencer 32 is formed. The main flow of the exhaust gas flowing through the first pipeline 8 goes through the first installation pipe 30 into the right-hand chamber 40 and from there, so to speak, backwards through the second installation pipe 34 into the left-hand chamber 36, with additional quantities escaping through the perforations described as a result of the exhaust-gas pressure pulsations and enter.

Das weiter vorn beschriebene, linke, offene Ende 42 der Schale 24 liegt in der linken Kammer 36, so daß das Abgas nach Passieren des Schalldämpfers 32 von dort durch die zwei Abgasbehandlungskörper 18, 20 strömen und schließlich durch die dritte Rohrleitung 12 abströmen kann. Insgesamt ergibt sich somit ein im wesentlichen S-förmiger oder mäanderförmiger Verlauf der Strömung des Abgases durch das Gehäuse 2.The left, open end 42 of the shell 24 described further above lies in the left chamber 36, so that the exhaust gas after passing through the muffler 32 can flow from there through the two exhaust gas treatment bodies 18, 20 and finally flow out through the third pipeline 12. Overall, this results in an essentially S-shaped or meandering course of the flow of the exhaust gas through the housing 2.

Die zweite Rohrleitung 10 ist im Inneren des Gehäuses 2 zunächst geradlinig fortgesetzt und führt durch eine Befestigungsöffnung in der ersten Querwand 26. Dahinter biegt die Rohrleitung etwa rechtwinklig ab und führt durch eine Öffnung in der Schale 24 in den Raum 44 zwischen den axial beabstandeten Abgasbehandlungskörpern 18, 20.The second pipeline 10 is initially continued in a straight line inside the housing 2 and leads through a fastening opening in the first transverse wall 26. Behind it, the pipeline bends approximately at right angles and leads through an opening in the shell 24 into the space 44 between the axially spaced exhaust gas treatment bodies 18 , 20th

Irgendwo zwischen der eingangs beschriebenen Abzweigung 16 und dem Eintritt in das Gehäuse 2 ist in der ersten Rohrleitung 8 eine erste Klappe 46 angeordnet. Die erste Klappe 46 läßt sich zwischen einer Offenstellung, in der sie im wesentlichen parallel zur Strömungsrichtung des Abgases liegt, und einer Schließstellung, in der sie im wesentlichen rechtwinkelig zur Abgasströmungsrichtung steht, verschwenken. Um dies zu veranschaulichen, ist in der Zeichnung eine Zwischenstellung gezeichnet. Irgendwo zwischen der Abzweigung 16 und dem Eintritt in das Gehäuse 2 ist in der zweiten Rohrleitung 10 eine zweite Klappe 48 angeordnet. Die zweite Klappe 48 läßt sich schwenkend zwischen einer Offenstellung und einer Schließstellung bewegen, analog wie zuvor für die erste Klappe 46 beschrieben.Somewhere between the branch 16 described at the beginning and the entry into the housing 2, a first flap 46 is arranged in the first pipeline 8. The first flap 46 can be pivoted between an open position, in which it lies essentially parallel to the flow direction of the exhaust gas, and a closed position, in which it is essentially perpendicular to the exhaust gas flow direction. In order to illustrate this, an intermediate position is drawn in the drawing. Somewhere between the branch 16 and the entry into the housing 2, a second flap 48 is arranged in the second pipeline 10. The second flap 48 can be pivoted between an open position and a closed position, analogously to that described for the first flap 46.

Außerdem befinden sich etwas oberhalb des ersten Einbaurohrs 30 in der ersten Querwand 26 eine kleinere Öffnung 50 und in der zweiten Querwand 28 eine kleinere Öffnung 52, so daß durch diese Öffnungen 50 und 52 Überströmvorgänge zwischen den drei Kammern 36, 38, 40 stattfinden können. Diese Öffnungen 50, 52 können auch weggelassen sein.In addition, there is a smaller opening 50 in the first transverse wall 26 and a smaller opening 52 in the second transverse wall 28, so that overflow processes between the three chambers 36, 38, 40 can take place through these openings 50 and 52. These openings 50, 52 can also be omitted.

Wenn man sich die beschriebene Abgasanlage ohne die Abzweigung 16 und die zweite Rohrleitung 10 einschließlich ihrer Fortsetzung bis hin zum Raum 44 zwischen den beiden Abgasbehandlungskörpern 18, 20 vorstellt, hat man einen Hauptströmungsweg der Abgasanlage vor sich, gebildet durch die erste Rohrleitung 8, den zuvor beschriebenen Strömungswegbereich durch den Schalldämpfer 32, den anschließenden Strömungswegbereich zuerst durch den ersten Abgasbehandlungskörper 18, dann durch den Raum 44, dann durch den zweiten Abgasbehandlungskörper 20, und schließlich durch die dritte Rohrleitung 12, normalerweise mit Nachschalldämpfer, bis zum Austrittsende. Von der Abzweigung 16 an bildet die zweite Rohrleitung 10, einschließlich ihrer Fortsetzung innerhalb des Gehäuses 2 bis hin zu dem Raum 44 zwischen den beiden Abgasbehandlungskörpern 18, 20, einen Bypass-Strömungsweg. Der durch den Bypass-Strömungsweg überbrückte Abschnitt des zuvor beschriebenen Hauptströmungswegs erstreckt sich somit von der Abzweigung 16 bis zu dem Raum 44.If you imagine the described exhaust system without the branch 16 and the second pipeline 10 including its continuation up to the space 44 between the two exhaust gas treatment bodies 18, 20, you have a main flow path of the exhaust system in front of you, formed by the first pipeline 8, the one before described flow path area through the muffler 32, the subsequent flow path area first through the first exhaust treatment body 18, then through the space 44, then through the second exhaust treatment body 20, and finally through the third pipeline 12, usually with rear silencer, to the outlet end. From the branch 16 onwards, the second pipeline 10, including its continuation within the housing 2 to the space 44 between the two exhaust gas treatment bodies 18, 20, forms a bypass flow path. The section of the main flow path described above bridged by the bypass flow path thus extends from the branch 16 to the space 44.

Wenn der Verbrennungsmotor, zu dem die beschriebene Abgasanlage gehört, im kalten Zustand oder im nicht betriebswarmen Zustand gestartet wird, befindet sich die erste Klappe 46 in ihrer Schließstellung und befindet sich die zweite Klappe 48 in ihrer Offenstellung. Somit strömt das Abgas, abgesehen von einer kleineren Leckströmung an der ersten Klappe 46 trotz ihrer Schließstellung vorbei, ausschließlich durch die zweite Rohrleitung 10 bzw. den Bypass-Strömungsweg. Das Abgas umgeht den Schalldämpfer 32 und den ersten Abgasbehandlungskörper 18. Es durchströmt den zweiten Abgasbehandlungskörper 20, wo die enthaltenen, gasförmigen Schadstoffe zumindest großenteils unschädlich gemacht werden, wie in der Beschreibungseinleitung angesprochen. Da das Abgas auf direktestem Wege dem zweiten Abgasbehandlungskörper 20 zuströmt, wird dieser optimal rasch auf seine gewünschte Mindestarbeitstemperatur erwärmt.When the internal combustion engine, to which the described exhaust system belongs, is started in the cold state or in the non-operating state, the first flap 46 is in its closed position and the second flap 48 is in its open position. Except for this, the exhaust gas flows of a smaller leakage flow past the first flap 46 despite its closed position, exclusively through the second pipeline 10 or the bypass flow path. The exhaust gas bypasses the muffler 32 and the first exhaust gas treatment body 18. It flows through the second exhaust gas treatment body 20, where the gaseous pollutants contained are at least largely made harmless, as mentioned in the introduction to the description. Since the exhaust gas flows in the most direct way to the second exhaust gas treatment body 20, the latter is optimally heated to its desired minimum working temperature.

Trotz der geschlossenen ersten Klappe 46 gelangen auch in diesem Zustand kleinere Abgasmengen aufgrund der Abgaspulsationen quasi rückwärts durch den ersten Abgasbehandlungskörper 18 bis hin zum Bereich des Schalldämpfers 32. Da es sich hierbei jedoch nicht um eine echte Durchströmung handelt, hält sich der Wärmeverlust aus dem Abgas an den ersten Behandlungskörper 18, an die Einbaurohre 30 und 34 des Schalldämpfers 32 sowie an die Wände 4, 6 des Gehäuses 2 insgesamt sehr in Grenzen. Dennoch findet infolge der soeben beschriebenen Abgaspulsationen im Bereich des Schalldämpfers 32 eine gewisse Schalldämpfung statt. Außerdem ist anzumerken, daß die zweite Rohrleitung 10 einen deutlich geringeren Durchmesser als die erste Rohrleitung 8 besitzt, so daß die wärmeabgebende Oberfläche der zweiten Rohrleitung 10 wesentlich geringer als die bei Durchströmung wärmeabgebende Oberfläche der ersten Rohrleitung 8 ist, was eine weitere Verringerung der Wärmeverluste aus dem Abgas an die Umgebung mit sich bringt. Schließlich ist anzumerken, daß die Schale 24 allseits Abstand zur Umfangswand 4 des Gehäuses 2 hat, so daß mit Ausnahme der Wärmeleitung durch die Querwände 26, 28 die Wärmeverluste von der Schale 24 an die Umgebung sehr gering sind.Despite the closed first flap 46, even in this state, smaller amounts of exhaust gas get backwards through the first exhaust gas treatment body 18 to the area of the muffler 32 due to the exhaust gas pulsations. However, since this is not a real flow, the heat loss from the exhaust gas persists on the first treatment body 18, on the installation tubes 30 and 34 of the silencer 32 and on the walls 4, 6 of the housing 2 as a whole within very limited limits. Nevertheless, due to the exhaust gas pulsations just described, a certain amount of sound absorption takes place in the area of the silencer 32. It should also be noted that the second pipeline 10 has a significantly smaller diameter than the first pipeline 8, so that the heat-emitting surface of the second pipeline 10 is significantly smaller than the surface of the first pipeline 8 that emits heat when flowing through, which further reduces the heat losses brings the exhaust gas to the environment. Finally, it should be noted that the shell 24 is spaced on all sides to the peripheral wall 4 of the housing 2, so that with the exception of heat conduction through the transverse walls 26, 28 the heat losses from the shell 24 to the environment are very low.

Sobald der zweite Abgasbehandlungskörper 20 eine Temperatur erreicht hat, die ein Stück oberhalb seiner Mindestarbeitstemperatur liegt, wird die erste Klappe 46 geöffnet und die zweite Klappe 48 geschlossen. Jetzt strömt das gesamte Abgas - mit Ausnahme einer gewissen Leckströmmenge an der geschlossenen zweiten Klappe 48 vorbei - durch den weiter vorn beschriebenen Abschnitt des Hauptströmungswegs, als wenn der Bypass-Strömungsweg nicht vorhanden wäre. Jetzt tritt der Schalldämpfer 32 voll in Funktion, die beiden Abgasbehandlungskörper 18, 20 werden nacheinander durchströmt mit dem Ergebnis optimaler Schadstoffreduzierung. Auch der erste Abgasbehandlungskörper 18 erwärmt sich nun rasch. Wenn der Verbrennungsmotor für längere Zeit mit relativ hoher Last betrieben wird, ergibt sich der Effekt, daß das Abgas vor seiner Zuströmung zum ersten Abgasbehandlungskörper 18 infolge der vorherigen Durchströmung durch den Schalldämpfer 32 und infolge der Wärmeabgabe der (im Vergleich zu einem Schalldämpfer ohne Abgasbehandlungskörper im gleichen Gehäuse) großen Wände 4, 6 des Gehäuses 2 beträchtlich abgekühlt wird. Infolgedessen ergibt sich erfindungsgemäß vergleichsweise ein Kühlbleiben der Abgasbehandlungskörper 18, 20 in derartigen Betriebsphasen, wodurch die Gefahr einer Temperaturschädigung der Abgasbehandlungskörper 18, 20 erheblich reduziert ist.As soon as the second exhaust gas treatment body 20 has reached a temperature which is slightly above its minimum working temperature, the first flap 46 is opened and the second flap 48 is closed. Now all of the exhaust gas - with the exception of a certain amount of leakage flow past the closed second flap 48 - flows through the section of the main flow path described further above as if the bypass flow path were not present. Now the muffler 32 comes into full operation, the two exhaust gas treatment bodies 18, 20 are flowed through in succession with the result of optimal pollutant reduction. The first exhaust gas treatment body 18 now also heats up rapidly. If the internal combustion engine is operated at a relatively high load for a long period of time, there is the effect that the exhaust gas before it flows into the first exhaust gas treatment body 18 as a result of the previous flow through the muffler 32 and as a result of the heat dissipation of the (compared to a muffler without an exhaust gas treatment body in same housing) large walls 4, 6 of the housing 2 is cooled considerably. As a result, according to the invention, the exhaust gas treatment bodies 18, 20 comparatively remain cool in such operating phases, as a result of which the risk of temperature damage to the exhaust gas treatment bodies 18, 20 is considerably reduced.

Wenn man die Wellen der ersten Klappe 46 und der zweiten Klappe 48 in die Zeichnungsebene legt, statt rechtwinkelig zur Zeichnungsebene wie gezeichnet, kann man auch eine gemeinsame Welle für beide Klappen 46, 48 vorsehen, welche den Abstand der ersten Rohrleitung 8 und der zweiten Rohrleitung 10 überbrückt, und kann damit beide Klappen 46, 48 gleichzeitig verschwenken. Es versteht sich, daß in diesem Fall die Klappen 46, 48 um 90° winkelversetzt auf dieser gemeinsamen Welle angeordnet sind, damit gleichzeitig zum Schließen der einen Klappe ein Öffnen der anderen Klappe und umgekehrt stattfindet.If you place the waves of the first flap 46 and the second flap 48 in the drawing plane instead of at right angles to the drawing plane as drawn, you can also use a common shaft for provide both flaps 46, 48, which bridges the distance between the first pipeline 8 and the second pipeline 10, and can thus pivot both flaps 46, 48 simultaneously. It is understood that in this case the flaps 46, 48 are arranged at an angle of 90 ° on this common shaft, so that at the same time an opening of the other flap takes place to close one flap and vice versa.

Alternativ ist es auch möglich, mit nur einer Klappe im Bereich der Abzweigung 16 auszukommen. Diese Klappe verschließt entweder die erste Rohrleitung 8 und öffnet zugleich damit die zweite Rohrleitung 10 oder umgekehrt. Zu diesem Zweck ist es sinnvoll, im Bereich der Abzweigung 16 der zweiten Rohrleitung 10 den gleichen Durchmesser wie der ersten Rohrleitung 8 zu geben. Der Vollständigkeit halber wird erwähnt, daß man die zweite Klappe 48 auch weglassen kann. In diesem Fall strömt bei geöffneter erster Klappe 46 immer noch ein Teil des Abgases durch den Bypass-Strömungsweg.Alternatively, it is also possible to make do with only one flap in the region of the branch 16. This flap either closes the first pipe 8 and at the same time thus opens the second pipe 10 or vice versa. For this purpose, it makes sense to give the same diameter as the first pipe 8 in the region of the branch 16 of the second pipe 10. For the sake of completeness, it is mentioned that the second flap 48 can also be omitted. In this case, with the first flap 46 open, part of the exhaust gas still flows through the bypass flow path.

Es wird darauf hingewiesen, daß die beiden Abgasbehandlungskörper 18, 20 nicht unbedingt in Strömungsrichtung nacheinander angeordnet sein müssen, wie es beim beschriebenen Ausführungsbeispiel der Fall ist. Stattdessen kann man die Abgasbehandlungskörper 18, 20 durchströmungsmäßig parallelgeordnet vorsehen, also beispielsweise übereinander in der Zeichnungsfigur. Die zweite Rohrleitung 10 kann im Raum vor den beiden Abgasbehandlungskörpern 18, 20 der linken Kammer 36 münden. Um einen der beiden Abgasbehandlungskörper 18, 20 von der unmittelbaren Durchströmung abzukoppeln, könnte man z.B. von jedem Abgasbehandlungskörper 18, 20 abströmseitig einen eigenen Abgaskanal vorsehen, die sich zu der dritten Rohrleitung 12 vereinigen. In einer dieser beiden Abgaskanäle wäre eine Klappe vorzusehen. Wenn diese Klappe geschlossen ist, wird der diesem Abgaskanal zugeordnete Abgasbehandlungskörper nicht unmittelbar durchströmt.It is pointed out that the two exhaust gas treatment bodies 18, 20 do not necessarily have to be arranged one after the other in the flow direction, as is the case in the exemplary embodiment described. Instead, the exhaust gas treatment bodies 18, 20 can be arranged in parallel in terms of flow, for example one above the other in the drawing figure. The second pipeline 10 can open into the space in front of the two exhaust gas treatment bodies 18, 20 of the left chamber 36. In order to decouple one of the two exhaust gas treatment bodies 18, 20 from the direct flow, it would be possible, for example, to provide a separate exhaust gas channel for each exhaust gas treatment body 18, 20 on the outflow side, which closes combine the third pipeline 12. A flap would have to be provided in one of these two exhaust gas ducts. If this flap is closed, the exhaust gas treatment body associated with this exhaust gas duct is not directly flowed through.

Zur automatischen Umstellung der beiden beschriebenen Klappen 46 und 48 kann man einen beispielsweise hinter dem zweiten Abgasbehandlungskörper 20 angeordneten Temperaturfühler vorsehen. Wenn die von diesem Temperaturfühler erfaßte Temperatur ein Stück oberhalb der Mindestarbeitstemperatur des Abgasbehandlungskörpers ist, hat der zweite Abgasbehandlungskörper 20 mit Sicherheit seine Mindestarbeitstemperatur erreicht. Es wird ein entsprechendes Signal an ein Steuergerät gegeben, welches dann das Umstellen der Klappen 46, 48 mittels geeigneter Antriebe auslöst.For the automatic changeover of the two flaps 46 and 48 described, a temperature sensor arranged, for example, behind the second exhaust gas treatment body 20 can be provided. If the temperature detected by this temperature sensor is a little above the minimum working temperature of the exhaust gas treatment body, the second exhaust gas treatment body 20 has certainly reached its minimum working temperature. A corresponding signal is sent to a control unit, which then triggers the flaps 46, 48 to be changed over by means of suitable drives.

Claims (8)

Abgasanlage für Verbrennungsmotoren, mit einem Hauptströmungsweg, der einen Schalldämpfer (32) und - in Strömungsrichtung diesem nachgeordnet - zwei katalytisch wirkende Abgasbehandlungskörper (18,20) aufweist,
dadurch gekennzeichnet,
daß ein Bypass-Strömungsweg (10) für einen Abschnitt (8,30,40,34,36,18) des Hauptströmungswegs vorgesehen ist, der den Schalldämpfer (32) und einen der zwei Abgasbehandlungskörper (18,20) umgeht;
und daß der Abschnitt (8,30,40,34,36,18) des Hauptströmungswegs schließbar ist.Exhaust system for internal combustion engines, with a main flow path, which has a silencer (32) and - downstream of this in the direction of flow - two catalytic exhaust gas treatment bodies (18, 20),
characterized by
that a bypass flow path (10) is provided for a portion (8,30,40,34,36,18) of the main flow path that bypasses the muffler (32) and one of the two exhaust treatment bodies (18,20);
and that the section (8,30,40,34,36,18) of the main flow path is closable. Abgasanlage nach Anspruch 1,
dadurch gekennzeichnet,
daß der Schalldämpfer (32) und die Abgasbehandlungskörper (18,20) ein gemeinsames Gehäuse (2) besitzen.Exhaust system according to claim 1,
characterized by
that the muffler (32) and the exhaust gas treatment body (18, 20) have a common housing (2). Abgasanlage nach einem der Ansprüche 1 und 2,
dadurch gekennzeichnet,
daß die Abgasbehandlungskörper (18,20) in Strömungsrichtung nacheinander angeordnet sind.Exhaust system according to one of claims 1 and 2,
characterized by
that the exhaust gas treatment body (18, 20) are arranged one after the other in the flow direction. Abgasanlage nach einem der Ansprüche 1 bis 3,
dadurch gekennzeichnet,
daß der Bypass-Strömungsweg (10) schließbar ist.Exhaust system according to one of claims 1 to 3,
characterized by
that the bypass flow path (10) can be closed. Abgasanlage nach einem der Ansprüche 2 bis 4,
dadurch gekennzeichnet,
daß Schalldämpfer (32) und Abgasbehandlungskörper (18,20) im Gehäuse (2) derart nebeneinander angeordnet sind, daß im Betrieb das Abgas im wesentlichen S-förmig strömt.Exhaust system according to one of claims 2 to 4,
characterized by
that muffler (32) and exhaust gas treatment body (18, 20) are arranged side by side in the housing (2) in such a way that the exhaust gas flows essentially S-shaped during operation. Abgasanlage nach einem der Ansprüche 1 bis 5,
dadurch gekennzeichnet,
daß der Schalldämpfer (32) als 3-Kammer-Reflexions-Schalldämpfer ausgebildet ist.Exhaust system according to one of claims 1 to 5,
characterized by
that the muffler (32) is designed as a 3-chamber reflection muffler. Abgasanlage nach einem der Ansprüche 1 bis 6,
dadurch gekennzeichnet,
daß der Abschnitt (8,30,40,34,36,18)des Hauptströmungswegs eine erste Rohrleitung (8) aufweist,
daß der Bypass-Strömungsweg (10) eine zweite Rohrleitung (10) aufweist
und daß der Strömungsquerschnitt der zweiten Rohrleitung (10) kleiner ist als der Strömungsquerschnitt der ersten Rohrleitung (8).Exhaust system according to one of claims 1 to 6,
characterized by
that the section (8, 30, 40, 34, 36, 18) of the main flow path has a first pipeline (8),
that the bypass flow path (10) has a second pipe (10)
and that the flow cross section of the second pipe (10) is smaller than the flow cross section of the first pipe (8). Abgasanlage nach einem der Ansprüche 2 bis 7,
dadurch gekennzeichnet,
daß in dem gemeinsamen Gehäuse (2) Querwände (26,28) vorhanden sind,
daß die Abgasbehandlungskörper (18,20) durch die Querwände (26,28) abgestützt sind,
und daß Einbaurohre (30,34) des Schalldämpfers (32) ebenfalls durch die Querwände (26,28) abgestützt sind.Exhaust system according to one of claims 2 to 7,
characterized by
that transverse walls (26, 28) are present in the common housing (2),
that the exhaust gas treatment bodies (18, 20) are supported by the transverse walls (26, 28),
and that installation pipes (30, 34) of the silencer (32) are also supported by the transverse walls (26, 28).
EP93121040A 1992-12-31 1993-12-28 Exhaust device for internal combustion engines Expired - Lifetime EP0604992B1 (en)

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Application Number Priority Date Filing Date Title
DE4244614A DE4244614A1 (en) 1992-12-31 1992-12-31 Exhaust system for internal combustion engines
DE4244614 1992-12-31

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EP0604992B1 EP0604992B1 (en) 1996-05-22

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CN103362599A (en) * 2013-08-01 2013-10-23 北京汽车股份有限公司 Exhaust noise regulating system, exhaust noise regulating method and vehicle
CN103362599B (en) * 2013-08-01 2015-10-14 北京汽车研究总院有限公司 Exhaust sound regulating system, exhaust sound regulating method and vehicle
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DE4244614A1 (en) 1994-07-07
EP0604992B1 (en) 1996-05-22
DE59302688D1 (en) 1996-06-27

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