Patent Application
20220018272
The disclosure relates to a muffler for an exhaust system of a vehicle.
Mufflers for exhaust systems are known in different designs.
To achieve the maximum possible broadband attenuation, both the functional principle of absorption and that of reflection are used, among others, which are for example realized in separate chambers within a single outer housing of the muffler.
To additionally attenuate low frequencies, a further chamber may be provided as part of a Helmholtz resonator in mufflers. The latter can be designed as a so-called branch resonator, in which a resonator chamber, also known as a Helmholtz chamber, is connected to the tube through which the exhaust gas flows via a resonator tube which forms the neck of the Helmholtz resonator.
Such a Helmholtz resonator attenuates a precisely defined frequency, namely the resonance frequency thereof which depends, among other things, on the volume of the Helmholtz chamber, the length of the neck, and the cross-sectional area of the neck. Thus, in order to adapt the sound attenuation by the Helmholtz resonator to a specific engine or engine type, one or more of the parameters mentioned can be varied in a purposeful manner
Depending on the engine type, it may also be provided that the exhaust system includes two exhaust pipes which guide the exhaust gases from the engine to a tailpipe of the exhaust system. Two separate Helmholtz chambers are then formed in a muffler having two exhaust pipes. Each exhaust pipe is connected to the corresponding Helmholtz chamber via an appropriate opening in the exhaust pipe and an appropriate feed body. This leads to bulky mufflers.
The disclosure simplifies the structure of a muffler for an exhaust system having two exhaust pipes.
A muffler for an exhaust system of a vehicle includes an outer housing in an interior of which a Helmholtz chamber is formed, a feed body, and two exhaust pipes. The feed body has an opening fluidically connected to the Helmholtz chamber and forms a neck of a Helmholtz resonator comprising the Helmholtz chamber. The exhaust pipes extend at least in sections within the outer housing, are spaced apart from each other, and form a flow path for an exhaust gas through the outer housing. The exhaust pipes each have at least two exhaust pipe sections which are entirely spaced apart from each other by a gap in one flow direction of the exhaust gas. The feed body surrounds the exhaust pipes over an entire circumference in the region of the gaps and fluidically connects the exhaust pipes to the Helmholtz chamber.
The disclosure is based on the basic idea to form a common feed body and thus a common neck and a common Helmholtz chamber for the two exhaust pipes, i.e. a Helmholtz resonator for both exhaust pipes. In this way, the structure of the muffler is simplified. Furthermore, the exhaust pipe sections are spaced apart from each other in the direction of the flow path of the exhaust gas through the exhaust pipes, such that a simple fluidic connection is established between the feed body and the exhaust pipes. In particular, no additional holes have to be cut or punched into the tubes forming the exhaust pipe.
The exhaust pipe sections are thus completely separated and spaced apart from each other and accordingly have a certain distance with respect to each other.
The distance of the exhaust pipe sections with respect to each other is, for example, adapted to a resonance frequency to be attenuated by the Helmholtz resonator.
One aspect of the disclosure provides that the exhaust pipes extend parallel to each other. A compact structure of the muffler is thus possible.
Alternatively or additionally, the exhaust pipes may extend in a linear or curved manner through the outer housing. The muffler can thus be mounted at any place along the exhaust system as it can simply be adapted to a predetermined course of the exhaust pipes.
To permit a simple mounting of the feed body, the feed body may have two half-shells which together surround the exhaust pipes. In the region of the gaps, the half-shells are placed onto the exhaust pipe sections and connected to each other from opposite sides which run transversely to the flow path of the exhaust gas.
The shape and volume of the feed body, i.e. the shape of the half-shells, may be adapted to a resonance frequency to be attenuated. In this way, it is possible to attenuate a specific frequency.
The length of the feed body and/or the cross-section of the feed body is adapted to the resonance frequency, for example.
In one design of the disclosure, the feed body is connected to the exhaust pipe sections by an intermaterial bond. The feed body is thus firmly positioned in a specific place along the exhaust pipe.
The feed body is fastened to the exhaust pipe sections by welding or soldering, for example. These fastening types have a good heat resistance.
The feed body may have two annular sections, each annular section surrounding a gap. In this way, the annular section only has very little influence on the flow behavior of the exhaust gas from the gap into the feed body.
On the inside, the annular sections have a larger cross-section than the exhaust pipes, such that an annular space is additionally produced radially outside the gap, into which exhaust gas from the gap can escape and can flow into the feed body.
In one design of the disclosure, the feed body has a feed section which extends from both annular sections, opens into the Helmholtz chamber, and extends between the exhaust pipes.
In other words, the space between the exhaust pipes is used for the feed body. In this way, a very compact muffler can be provided.
The feed section is tubular, for example.
The outer surfaces of the exhaust pipes in particular form part of the feed body in the region of the feed section. The cross-section of the feed body is thus also influenced by the distance between the exhaust pipes. This distance is adapted to the resonance frequency to be attenuated, for example.
For example, the feed section is delimited in sections by two tab-shaped projections on the half-shells which extend from the annular sections and each rest on both exhaust pipes so as to act as bridges between the exhaust pipes. The neck of the Helmholtz resonator is thus delimited by the exhaust pipe wall and the tab-shaped projections.
The feed section may extend parallel to the flow direction of the exhaust gas in the exhaust pipes. In this way, the area between the exhaust pipes can preferably, even completely, be used for the feed body. The structure of the muffler is thus further simplified, and the weight thereof is reduced.
In one embodiment, the Helmholtz chamber is delimited at least in sections by an inner envelope surface of the outer housing. In this way, the resonance frequency of the Helmholtz resonator can be adjusted directly by the geometrical shape of the outer housing.
A partition wall may be arranged within the outer housing, which delimits the Helmholtz chamber in sections and separates a further muffler chamber in the interior of the outer housing from the Helmholtz chamber. Therefore, different techniques can be used in the muffler to attenuate the sound emissions. An effective attenuation of the sound emissions is thus ensured.
It is also conceivable that more than one partition wall, for example two or three partition walls are arranged within the outer housing. In this way, the volume of the Helmholtz chamber can simply be adapted for different engine versions or to frequencies or frequency spectra to be attenuated.
The further muffler chamber is an absorption or reflection chamber, for example.
Further features and advantages of the disclosure will become apparent from the description below and from the accompanying drawings to which reference is made below and in which:
The vehicle 10 includes an internal combustion engine 12 and an exhaust system 14. A muffler 16 is arranged in the exhaust system 14. The exhaust system 14 guides an exhaust gas produced in the internal combustion engine 12 through the muffler 16 to an end of the exhaust system 14, here to a tailpipe 17. The sound emissions produced by the combustion process taking place in the internal combustion engine 12 are thus attenuated in the muffler 16.
The muffler 16 may constitute a front muffler, a central muffler or a rear muffler of the exhaust system 14.
In other words, the muffler 16 can be arranged in any place in the exhaust system 14 and does not have to be directly connected to the tailpipe 17, as shown schematically in
The muffler 16 represented in
The outer housing 18 of the muffler 16 may also be formed, for example, by two half-shells, a winding envelope or a tube, instead of being formed by the envelope 20 and the closure plates 22.
A partition wall 24 is arranged within the outer housing 18 and divides the interior of the outer housing 18 into two chambers 26, 28, more specifically into a Helmholtz chamber 26 and a further muffler chamber 28.
Therefore, the partition wall 24 is directly adjacent to the inner envelope surface 30 of the outer housing 18.
In the embodiment of
Furthermore, the muffler 16 has two exhaust pipes 32 which extend in the longitudinal direction L of the muffler 16 and through the outer housing 18.
In other words, the exhaust pipes 32 are thus arranged at least in sections within the outer housing 18.
The exhaust pipes 32 are laterally spaced apart from each other, i.e. they are separated by a distance “d” transversely to the direction of extension of the exhaust pipes 32.
In the embodiment of
Generally, it is also conceivable that the exhaust pipes 32 extend in a curved manner through the outer housing 18.
The exhaust pipes 32 form a flow path for an exhaust gas. Each exhaust pipe 32 respectively includes two exhaust pipe sections 34 which are entirely spaced apart from each other in the flow direction of the exhaust gas (represented by arrows 33).
In other words, a laterally entirely circumferential gap 36 is respectively provided between the exhaust pipe sections 34 in the respective flow path through the exhaust pipes 32.
In addition to the outer housing 18 and the exhaust pipes 32, the muffler 16 has a feed body 38 which is formed by two half-shells 39 (
The feed body 38 is thus a two-piece element, the respectively one-piece half-shells 39 being placed onto the exhaust pipes 32 from two opposite sides of the exhaust pipes 32, being firmly connected to each other and being connected to the exhaust pipes 32.
The half-shells 39 are in particular connected to each other by an intermaterial bond and are also connected to the exhaust pipe sections 34 by an intermaterial bond, by soldering or welding, for example.
In the design of
In the region of the gaps 36, the feed body 38 has two annular sections 40. The annular sections 40 enclose the exhaust pipes 32 over the entire circumference in the region of the gaps 36, seals them with respect to the environment and form a flow path for the exhaust gas via the gaps 36 into the space between the exhaust pipes 32.
A feed section 42 in the shape of tab-like, plate-like projections of the feed body 38 extends from the downstream end of the annular sections 40. As the feed sections 42 are attached to the exhaust pipes 32, a channel 43 is produced which forms the neck of a Helmholtz resonator 41 (cf.
The feed section 42 also has an opening 44 (
The feed body 38 and the Helmholtz chamber 26 thus form a Helmholtz resonator 41 which attenuates specific frequencies occurring in the exhaust gas in a manner known per se.
The length I (
In other words, the cross-section and the volume of the feed body 38 are thus adapted to the resonance frequency in the region of the feed section 42.
The Helmholtz chamber 26 is of course also adapted to the resonance frequency.
The Helmholtz chamber 26 is fluidically connected to both exhaust pipes 32 (via the feed body 38). The muffler 16 therefore provides a Helmholtz resonator 41 for two exhaust pipes 32. In this way, the structure of a muffler 16 having two exhaust pipes 32 is simplified. It is in particular not necessary to arrange holes on the exhaust pipe sections 34; rather, the gap 36 is simply formed by a spaced apart arrangement of the exhaust pipe sections 34 with respect to each other.
Mechanically, the exhaust pipe sections 34 are firmly connected to each other by the feed body.
Although various embodiments have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the true scope and content of this disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 118 749.1 | Jul 2020 | DE | national |
This application is a U.S. non-provisional application claiming the benefit of German Application No. 10 2020 118 749.1, filed on Jul. 15, 2020, which is incorporated herein by reference in its entirety.
