Exhaust gas system for an internal combustion engine

Abstract

An exhaust gas system for an internal combustion engine includes a first exhaust gas line leading into a first muffler; a second exhaust gas line arranged fluidly parallel to the first exhaust gas line and leading into a second muffler, wherein the first and second exhaust gas lines are respectively connected upstream of the first and second muffler at a branch to a common exhaust gas feed line; a control valve arranged in the first exhaust gas line upstream of the first muffler; and a damping device fluidly arranged between the branch and the control valve and adapted for damping exhaust gas resonance vibrations.

Claims

1. An exhaust gas system for an internal combustion engine comprising: a first exhaust gas line leading into a first muffler; a second exhaust gas line arranged fluidly parallel to the first exhaust gas line and leading into a second muffler, said first and second exhaust gas lines respectively being connected upstream of the first and second muffler at a branch to a common exhaust gas feed line; a control valve arranged in the first exhaust gas line upstream of the first muffler; a damping device fluidly arranged between the branch and the control valve and adapted for damping exhaust gas resonance vibrations, said damping device including a housing having an entry end and an exit end for the exhaust gas in a flow direction, and at least one nozzle arranged within the housing in the flow direction of the exhaust gas at a downstream location of the housing in proximity of the exit end; and a cross section adjustment element provided in a flow connection between the first exhaust gas line and the second exhaust gas line.

2. The exhaust gas system of claim 1, wherein the damping device has a sound absorber.

3. The exhaust gas system of claim 2, wherein the sound absorber is constructed as a resonance absorber.

4. The exhaust gas system of claim 1, wherein the cross section adjustment element is constructed as a spring-loaded check valve.

5. The exhaust gas system of claim 1, wherein the at least one nozzle leads into an open-jet volume.

6. The exhaust gas system of claim 1, wherein the second exhaust gas line is configured without a control valve.

7. The exhaust gas system of claim 1, further comprising an exhaust gas turbocharger provided upstream of the branch.

8. The exhaust gas system of claim 1, wherein the nozzle is configured such as to cause a reduction of a flow cross section in the flow direction and to lead into an open-jet volume to thereby effect an increase of the flow cross section in the flow direction.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) In the following the invention is explained in more detail by way of the exemplary embodiments shown in the drawing without limiting the invention. It is shown in:

(2) FIG. 1 a schematic representation of a region of an exhaust gas system for an internal combustion engine, and

(3) FIG. 2 an embodiment of a damping device for damping exhaust gas resonance vibrations.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(4) FIG. 1 shows a schematic representation of an exhaust gas system 1, which is for example assigned to a here not further shown internal combustion engine. The exhaust gas system 1 has an exhaust gas feed line 2, which transitions at a branch 3 into a first exhaust gas line 4 and a second exhaust gas line 5. The first exhaust gas line 4 leads into a first muffler 6 and the second exhaust gas line into a second muffler 7. The mufflers 6 and 7 are preferably configured as end muffler or after-muffler. Insofar an end tube 8 or 9 is connected to each of the mufflers 6 and 7 on the corresponding side, which faces away from the exhaust gas line 4 or 5.

(5) The exhaust gas generated by the internal combustion engine flows through the exhaust gas feed line 2, which is for example connected to an exhaust manifold of the internal combustion engine, in the direction of the branch 3. There the exhaust gas feed line 2 ends or respectively transitions into the exhaust gas lines 4 and 5. Starting from the branch 3, the exhaust gas can insofar further flow through the exhaust gas lines 4 and 5. At the branch 3 for example a further muffler 10 is arranged, which is in particular configured as a pre-muffler or preferably as a middle muffler. The exhaust gas flowing through the exhaust gas feed line 2 correspondingly flows into the muffler 10 and from the muffler 10 into the first exhaust gas line 4 and the second exhaust gas line 5. Subsequently the exhaust gas can flow through the muffler 6 and 7 into the end tubes 8 and 9 and can be released through end tubes into an external environment 11 of the exhaust gas system 1.

(6) Upstream of the first muffler 6 a control valve 12 is provided in the first exhaust gas line 4, by means of which control valve a flow cross section of the first exhaust gas line 4 can be adjusted. The control valve 12 can correspondingly be used to block the first exhaust gas line completely, to partially release the first exhaust gas line or to completely release it. However because the flow path though the first exhaust gas line 4 from the branch 3 up to the control valve 12 is comparatively long, exhaust gas resonance vibrations may occur in particular as a result of the so-called Helmholtz-resonance. With respect to a mean flow cross section of the first exhaust gas line 4 the distance between the branch 3 and the control valve 12 or the beginning of the first exhaust gas line 4 and the control valve 12 is 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.

(7) For avoiding or at least damping the exhaust gas resonance vibrations, a damping device 13 is provided, which is here only indicated schematically. The damping device 13 can have a flow connection between the first exhaust gas line 4 and the second exhaust gas line 5, a sound absorber or a flow rectifier. Of course also any desired combination of these embodiments is conceivable so that for example the damping device 13 has the flow connection and the sound absorber, the damping device and the flow rectifier, the sound absorber and the flow rectifier or the flow connection, the sound absorber and the flow rectifier.

(8) In the embodiment, which has the flow connection between the first exhaust gas line 4 and the second exhaust gas line 5, for example a throttle or a cross section adjustment element 18 is provided, which is arranged in the flow connection. The cross section adjustment element is particularly constructed as a spring-loaded check valve. The sound absorber can be configured as an expansion and/or absorption chamber. As an alternative it can also be configured as a resonance absorber.

(9) FIG. 2 shows an embodiment of the damping device 13, which in this case is configured as a flow rectifier. Also indicated are the regions of the first exhaust gas line 4 upstream and downstream of the damping device 13 and the control valve 12. The damping device 13 has a housing 14, which initially has a constant inner flow cross section. However, in the housing at least one nozzle 15 is arranged. Preferably multiple nozzles 15, here for example 4 nozzles 15, are present in the housing 14 arranged one after the other in flow direction.

(10) The nozzles 15 cause a reduction of the flow cross section stating from the inner flow cross section of the housing 14 which can also be referred to as housing inner cross section. Preferably the reduction of the flow cross section is hereby continuous. The at least one nozzle 15, however preferably each nozzle 15, leads hi flow direction into an open-jet volume 16 into which the exhaust gas enters downstream of the respective nozzle 15. The exhaust gas flows through the damping device 13 in the direction of the arrows 17. Hereby essentially a reduction of the exhaust gas resonance vibrations, in particular the in the direction perpendicular to the flow direction indicated by the arrows 17, is caused.

(11) The length of the damping device 13 in flow direction is preferably dimensioned so that a predominant portion of the exhaust gas resonance vibrations, in particular almost all exhaust gas resonance vibrations, are sufficiently damped, preferably completely removed. By means of the damping device 13 it is thus possible to arrange the control valve 12 upstream of the first muffler 6. The latter is for example desirable with regard to mounting space because in this way the length of the end tube 8 can be reduced.