EP3175096A1

EP3175096A1 - Exhaust gas system for an internal combustion engine

Info

Publication number: EP3175096A1
Application number: EP15711430.7A
Authority: EP
Inventors: Axel Peters
Original assignee: Audi AG
Current assignee: Audi AG
Priority date: 2014-08-01
Filing date: 2015-03-20
Publication date: 2017-06-07
Anticipated expiration: 2035-03-20
Also published as: WO2016015791A1; DE102014011618B4; US20170211439A1; CN106574540A; US10458298B2; DE102014011618A1; CN106574540B; EP3175096B1

Abstract

The invention relates to an exhaust gas system (1) for an internal combustion engine, comprising a first exhaust gas line (4) opening into a first muffler (6) and a second exhaust gas line (5) opening into a second muffler (7) provided fluidically parallel to the first exhaust gas line (4), wherein the exhaust gas lines (4, 5) are connected upstream of the respective mufflers (6, 7) at a junction (3) to a common exhaust gas guide line (2). A control valve (12) is thereby provided, arranged in the first exhaust gas line (4) upstream of the first muffler (6), wherein a damping device (13) for damping exhaust gas resonance oscillations is provided fluidically between the junction (3) and the control valve (12).

Description

Exhaust system for an internal combustion engine

The invention relates to an exhaust system for an internal combustion engine, with a first exhaust pipe opening into a first silencer and a second exhaust pipe opening parallel to the first exhaust pipe and opening into a second silencer, wherein the exhaust pipes upstream of the respective silencer at a branch to a common Abgaszuführleitung are connected. The exhaust system is associated, for example, a motor vehicle, which also has the internal combustion engine. With the help of

Internal combustion engine, a torque can be provided, which is directed to a drive, in particular a propulsion, of the motor vehicle. The exhaust system serves to remove exhaust gas, which is generated by the internal combustion engine during its operation. The exhaust gas should now first flow through the common Abgaszuführleitung. For this purpose, the exhaust gas supply line, for example, to a

Exhaust manifold of the internal combustion engine connected. At the branch, the exhaust gas from the Abgaszuführleitung is introduced into both the first exhaust pipe and in the second exhaust pipe. At the branch so branch off the first exhaust pipe and the second exhaust pipe from the common Abgaszuführleitung from. In particular, the exhaust gas supply line ends at the branch, while the first exhaust pipe and the second exhaust pipe emanate from the branch. Both the first exhaust pipe and the second exhaust pipe are arranged so far downstream of the exhaust gas supply.

The first exhaust pipe opens into the first silencer, while the second exhaust pipe opens into the second silencer. That means Thus, that the first muffler and the second muffler respectively downstream of the branch in the respective exhaust pipe, ie the first exhaust pipe or the second exhaust pipe, are present. By means of the silencer, the noise generated by the internal combustion engine or the exhaust gas is to be damped, that is, reduced in its volume.

For example, the exhaust system has at least two tailpipes, one of the tailpipes fluidly with the first exhaust pipe and a second of the tailpipes fluidly with the second

Exhaust pipe is fluidly connected. In particular, the respective tailpipe is located downstream of the first muffler or of the second muffler. From the prior art, for example, the document DE 10 2004 046 184 A1 is known. This concerns a system for damping a

Exhaust noise from an engine with a first group of

switched-on cylinders and a second group of deactivatable cylinders. The system includes a first exhaust manifold connected to the first group of on-cylinders and a second exhaust manifold connected to the second group of deactivatable cylinders. The second exhaust manifold is connected to the first exhaust manifold so that the second exhaust manifold acts as a resonator to dampen sound from the first group of on-cylinders when the second group of cylinders is off.

It is an object of the invention to provide an exhaust system for an internal combustion engine, which has advantages over the prior art, In particular, an adjustable noise behavior with low space requirement or space allows.

This is achieved according to the invention with an exhaust system having the features of claim 1. It is provided that in the first exhaust pipe upstream of the first muffler, a control valve is arranged, wherein fluidically provided between the branch and the control valve, a damping device for damping exhaust gas resonant vibrations. The control valve is used to set a specific flow cross-section in the first exhaust pipe. The control valve is fluidically arranged between the branch and the first muffler, so that the flow connection between the branch and the first muffler or the

Flow cross section can be adjusted by means of the control valve. In particular, the flow connection may be interrupted, partially released or completely released, for which purpose the control valve is in a respectively corresponding position.

The silencers are designed, for example, as end silencers, to which an end pipe connects downstream of the respective exhaust pipe. Overall, therefore, for example, the following structure of

Exhaust system provided: The exhaust gas generated by the internal combustion engine is first supplied to the exhaust gas supply, for which purpose it is connected in particular to an exhaust manifold or a downpipe of the internal combustion engine. The Abgaszuführleitung leads up to the branch and goes there in the first exhaust pipe and the second exhaust pipe over. This means that the exhaust gas supply line ends at the branch, where it opens into both the first exhaust pipe and the second exhaust pipe. Both exhaust pipes are thus connected parallel to each other to the Abgaszuführleitung. Through the exhaust pipes, the exhaust gas can flow in the direction of the respective muffler. The mufflers are so far downstream of the branch connected to the respective exhaust pipe. The exhaust gas passes through the respective exhaust pipe in the corresponding silencer and from this into the corresponding tailpipe. It is thus provided that the first exhaust pipe opens into the first silencer and this is connected to a first tail pipe, so that the exhaust gas from the first exhaust pipe in the first silencer and can get out of this in the first tail pipe, if the control valve at least partially, in particular, completely, is opened.

In contrast, the second exhaust pipe opens into the second silencer, to which the second tail pipe is connected, so that the exhaust gas from the second exhaust pipe in the second silencer and from this can get into the second tailpipe. Particularly preferred is the

Flow connection between the branch and the second

Silencer and / or the second tailpipe permanently released and formed so far vacant valve. The exhaust gas generated by the internal combustion engine thus flows continuously through the second exhaust pipe, the second muffler and the second tailpipe.

Downstream of the first tail pipe and / or the second tail pipe, the exhaust gas enters an external environment of the exhaust system or of the motor vehicle. Using the control valve can now be selectively set whether the exhaust only through the second exhaust pipe or through both

Exhaust pipes flows and over the corresponding tailpipe in the

Outside environment is dissipated. The control valve may in principle be arranged downstream of the first silencer. This has the advantage that pressure pulses of the exhaust gas are damped in the first muffler, so it does not

may come unwanted resonance phenomena. However, this arrangement is space-consuming, so that according to the invention the control valve should be arranged upstream of the first muffler. However, such an arrangement may cause resonant vibrations in the first exhaust passage. For this reason, the control valve is the damping device for

Damping associated with exhaust resonance vibrations. These

Damping device is fluidically arranged between the branch and the control valve, so far upstream of the control valve, for example, in the first exhaust pipe. At least, however, it is associated with the first exhaust pipe. The damping device can

basically be designed in any way. Separate

Exemplary embodiments will be explained below.

In a preferred embodiment of the invention it is provided that the damping device has a flow connection between the first exhaust pipe and the second exhaust pipe. By the

Flow connection can pass exhaust gas from the first exhaust pipe into the second exhaust pipe and vice versa. Thus, pressure pulses, which may occur in the first exhaust line, in particular in the case of partially or completely closed control valve, in the direction of the second

Exhaust pipe to be dismantled.

The flow connection has, for example, a connecting line, which opens on the one hand into the first exhaust pipe and on the other hand into the second exhaust pipe. The mouth of the connecting line in the first exhaust pipe is present upstream of the control valve,

preferably immediately upstream of the control valve. Based on the flow path from a start of the first exhaust pipe or the branch up to the control valve, this means, for example, that the discharge point of the connecting line in the first exhaust pipe - starting from the beginning of the first exhaust pipe or the branch - at least 50%, at least 60th %, at least 70%, at least 75%, at least 80%, at least 90% or at least 95%. In particular, the flow path between the branch and the control valve is considered.

A further embodiment of the invention provides that in the

Flow connection is provided a throttle or a Querschnittsverstellelement. The throttle causes a permanent

Cross-section reduction in the flow connection or the connecting line. This means that a minimum flow cross section of the throttle is smaller than a smallest flow cross section of the first exhaust pipe and / or the second exhaust pipe. Alternatively, the

Cross-section adjustment present in the flow connection. By means of the cross-section adjustment element, the flow cross-section of the flow connection or the connection line can be adjusted. The setting can be provided in any way. In a further embodiment of the invention, it is provided that the cross-section adjustment element is present as a spring-loaded check valve. The check valve is designed in particular such that it allows only a crosstalk from the first exhaust pipe into the second exhaust pipe, so that pressure pulses, which in the first

Exhaust pipe occur, dismantled in the direction of the second exhaust pipe can be. In contrast, the check valve prevents a

Crosstalk from the second exhaust pipe in the direction of the first

Exhaust pipe. The check valve is acted upon by means of a spring element with a spring force. The spring force is chosen such that the

Check valve is closed in the presence of a mean pressure level in the first exhaust pipe and only when this average pressure level, for example, by pressure pulses, is opened so that the pressure pulses can be reduced and thus the exhaust resonance vibrations can be damped.

A preferred embodiment of the invention provides that the

Damping device has a sound absorber. The sound absorber comprises, for example, a hollow body, through which the exhaust gas flows or flows. The hollow body preferably has internal dimensions which are larger than the

Cross-sectional dimensions of the first exhaust pipe, so far as a sufficiently large damping volume is available. Of the

Sound absorber, for example, as an expansion chamber or as

Be designed absorption chamber. The expansion chamber is to be understood as meaning a chamber through which the exhaust gas flows, or a hollow space through which, for example, a sudden flow occurs

Durchströmungsquerschnittsvergrößerung and then -reduction is present. The cross-sectional jumps results in an effective damping of the exhaust resonance vibrations.

A particularly preferred embodiment of the invention provides that the sound absorber is present as a resonance absorber. The resonance absorber has, for example, a mass which is displaceably mounted or suspended. The energy contained in the exhaust resonance vibrations can be converted by means of this mass into kinetic energy. The maximum absorption occurs in the range of the natural frequency of the mass, which usually also the strongest vibrations of the mass can occur.

In a further embodiment of the invention can be provided that the damping device comprises a flow straightener. The flow rectifier is used for the targeted alignment of the flow through the flow rectifier or the orientation of

Vibrations in the flow. The flow rectifier can be referred to as far as, for example, as a sound-fast rectifier.

A further development of the invention provides that the flow rectifier has at least one nozzle which opens into a free-jet volume. The alignment or rectification of the flow through the flow straightener is effected by means of the nozzle, which in

Flow direction is preferably designed as a convergent nozzle. The nozzle causes so far a reduction of the first

Flow cross-section in the flow direction, whereby the

Vibration damped or in the flow direction

be aligned. The nozzle dampens vibrations in this respect

or turbulence, which in perpendicular to the

Flow direction or main flow direction standing direction.

The nozzle opens into a free-jet volume, which is to be understood as meaning that, immediately after the nozzle, there is a sudden flow

Cross-sectional extension is provided. For example, it is provided that the flow rectifier has a housing in which at least one nozzle, particularly preferably in the flow direction

successively a plurality of nozzles are arranged, wherein immediately

downstream of each nozzle there is a sudden cross-sectional widening to a housing internal cross-section. Both fluidically before and fluidically after the nozzle is so far the same

Flow cross-section, namely the housing inner cross-section before.

According to another embodiment of the invention, it can also

be provided that the second exhaust pipe is formed Stellstellfrei. On such a configuration has already been mentioned above. In the second exhaust pipe so far there is no control valve, so that the flow connection between the branch and the second

Silencer is interruption free. Particularly preferably, the entire flow connection through the second exhaust pipe between the branch and the external environment is designed interruption-free or stellelfventilfrei.

Finally, it can be provided that an exhaust gas turbocharger is provided upstream of the branch. The exhaust-gas turbocharger or a turbine of the exhaust-gas turbocharger arranged upstream of the branch serves to convert flow energy of the exhaust gas into kinetic energy, which is subsequently used for compressing air, in particular fresh air. The air is subsequently, ie at a higher pressure level, supplied to the internal combustion engine. The exhaust gas turbocharger serves to increase the efficiency of the internal combustion engine and / or increase the power of the internal combustion engine.

It can be provided that the branch is present in a silencer or is formed by such. The muffler is for example as a pre-muffler, but particularly preferably as Middle silencer before. In such an embodiment, it is provided that the common exhaust gas supply line opens into the muffler and downstream of the two exhaust pipes lead out of the muffler. The exhaust gas thus flows through the Abgaszuführleitung in the muffler and is discharged through the two exhaust pipes again out of it.

The invention is of course also directed to an internal combustion engine with an exhaust system, the latter according to the above

Embodiments can be developed and developed. The invention also relates to a motor vehicle with an internal combustion engine, which has such an exhaust system. On the advantages of such an embodiment of the exhaust system has already been noted. The exhaust system, the

Internal combustion engine and / or the motor vehicle may be further developed according to the above statements, so that reference is made to this extent.

The invention will be explained in more detail with reference to the embodiments illustrated in the drawings, without any limitation of the invention. Showing:

Figure 1 is a schematic representation of a portion of a

Exhaust system for an internal combustion engine, and Figure 2 shows an embodiment of a damping device for

Damping of exhaust resonance vibrations.

1 shows a schematic view of an exhaust system 1, which is assigned for example to an internal combustion engine, not shown here. The exhaust system 1 has an exhaust gas supply line 2, which at a Branch 3 in a first exhaust pipe 4 and a second exhaust pipe 5 passes. The first exhaust pipe 4 opens into a first silencer 6, the second exhaust pipe into a second silencer 7. The

Silencers 6 and 7 are preferably as end silencer

or rear silencer executed. In that regard, to each of the muffler 6 and 7 on the corresponding exhaust pipe. 4

or 5 opposite side connected to a tail pipe 8 and 9, respectively.

The exhaust gas generated by the internal combustion engine flows through the

Abgaszuführleitung 2, which is connected, for example, to an exhaust manifold of the internal combustion engine, in the direction of the branch 3. There, the exhaust gas supply line 2 ends or goes into the exhaust pipes 4 and 5 via. The exhaust gas can continue to flow from the branch 3 through the exhaust pipes 4 and 5 so far. At the branch 3, for example, a further muffler 10 is arranged, which

is configured in particular as a front silencer or preferably as a middle silencer. The exhaust gas flowing through the exhaust gas supply line 2 accordingly flows into the muffler 10 and out of this into the first exhaust gas line 4 and the second exhaust gas line 5. Subsequently, the exhaust gas can pass through the mufflers 6 and 7 into the tail pipes 8 and 9 and through this into a Outside environment 11 of the exhaust system 1 are delivered. Upstream of the first muffler 6, a control valve 12 is provided in the first exhaust pipe 4, by means of which a

Flow cross-section of the first exhaust pipe 4 is adjustable. The control valve 12 can be used accordingly, the first

Completely block exhaust pipe 4, partially release it or completely release it. Because, however, the flow path through the first Exhaust pipe 4 from the branch 3 to the control valve 12 is comparatively long, it may lead to the formation of exhaust resonance vibrations, in particular by the so-called Helmholtz resonance. Based on a mean flow cross-section of the first exhaust pipe 4, the distance between the branch 3 and the control valve 12 and a beginning of the first exhaust pipe 4 and the

Control valve 12 of at least 10, at least 12.5, at least 15,

at least 17.5, at least 20, at least 25, at least 30, at least 40 or at least 50.

To avoid or at least to cushion the

Exhaust resonance vibrations, a damping device 13 is provided, which is only indicated here. The damping device 13 may have a flow connection between the first exhaust pipe 4 and the second exhaust pipe 5, a sound absorber or a flow straightener. Of course, any combination of these embodiments is conceivable, so that, for example, the

Damping device 13, the flow connection and the sound absorber, the damping device and the flow rectifier, the

Sound absorber and the flow straightener or the

Having flow connection, the sound absorber and the flow straightener.

In the embodiment having the flow communication between the first exhaust pipe 4 and the second exhaust pipe 5 is

For example, a throttle or a Querschnittsverstellelement

provided, which is arranged in the flow connection. The

Cross-section adjustment is particularly preferred as

spring-loaded check valve before. The sound absorber can Expansion and / or absorption chamber present. Alternatively, it can also be designed as resonance absorber.

2 shows an embodiment of the damping device 13, which is designed here as a flow rectifier. Also indicated are the areas of the first exhaust pipe 4 upstream and downstream of the damping device 13 and the control valve 12. Die

Damping device 13 has a housing 14, which initially has a constant internal flow cross-section. By doing

Housing, however, at least one nozzle 15 is arranged. Preferably, a plurality of nozzles 15, in this case, for example, four nozzles 15, are present successively in the housing 14 in the flow direction.

The nozzles 15 each cause a reduction of

Flow cross-section starting from the inner

Flow cross-section of the housing 14, which also as

'Housing internal cross-section can be called. Preferably, the reduction of the flow cross section is continuous. The at least one nozzle 15, but preferably each of the nozzles 15, opens into

Flow direction in a free jet volume 16, in which the exhaust gas downstream of the respective nozzle 15 enters as a free jet. The exhaust gas flows through the damping device 13 in the direction of the arrows 17. In this case, a reduction of the exhaust resonance vibrations, in particular in the direction perpendicular to the flow direction indicated by the arrows 17 direction is effected.

The length of the damping device 13 in the flow direction is

Preferably, such that a large part of

Exhaust resonance vibrations, in particular almost all

Exhaust resonance vibrations, sufficiently damped, preferably completely eliminated. With the aid of the damping device 13, it is therefore possible to arrange the control valve 12 upstream of the first muffler 6. The latter is, for example, for reasons of space of the

Exhaust system 1 desirable because so the length of the tail pipe 8 can be reduced.

Claims

claims

1. Exhaust system (1) for an internal combustion engine, with a first exhaust pipe (4) opening into a first silencer (6) and a fluidic parallel to the first exhaust pipe (4), in a second silencer (7) opening second exhaust pipe (5 ), wherein the exhaust pipes (4,5) upstream of the respective muffler (6,7) at a branch (3) to a common Abgaszuführleitung (2) are connected, characterized in that in the first

Exhaust pipe (4) upstream of the first muffler (6) a control valve (12) is arranged, wherein fluidically between the branch (3) and the control valve (12) is provided a damping device (13) for damping exhaust gas resonant vibrations.

2. Exhaust system according to claim 1, characterized in that the damping device (13) has a flow connection between the first exhaust pipe (4) and the second exhaust pipe (5).

3. Exhaust system according to one of the preceding claims, characterized in that in the flow connection, a throttle or a

Cross-section adjustment is provided.

4. Exhaust system according to one of the preceding claims, characterized in that the Querschnittsverstellelement as

spring-loaded check valve is present.

5. Exhaust system according to one of the preceding claims, characterized in that the damping device (13) has a sound absorber.

6. Exhaust system according to one of the preceding claims, characterized in that the sound absorber is present as a resonance absorber.

7. Exhaust system according to one of the preceding claims, characterized in that the damping device (13) has a

Having flow rectifier.

8. Exhaust system according to one of the preceding claims, characterized in that the flow rectifier has at least one in a free jet volume (16) opening nozzle (15).

9. Exhaust system according to one of the preceding claims, characterized in that the second exhaust pipe (5) is formed without adjusting valve.

10. Exhaust system according to one of the preceding claims, characterized in that upstream of the branch (3), an exhaust gas turbocharger is provided.