DE102006033053B3 - Motor vehicle silencer has upper side lining section consisting of textile material of synthetic fibers which deflects moisture, and bottom side lining section consisting of textile material of synthetic fibers which absorbs moisture - Google Patents

Abstract

The motor vehicle silencer has an upper side lining section (8), which consists of a textile material (10) of synthetic fibers which deflects moisture, and a bottom side lining section (9), which consists of a textile material (13) of synthetic fibers which absorbs moisture. At least one pipe support (15a-15c) of synthetic fibers is provided in the silencer housing (2). The pipe supports extend from the bottom lining section.

Description

The The invention relates to a motor vehicle silencer according to the features in the preamble of claim 1.

Muffler in the exhaust system of a motor vehicle serve to reduce the Exhaust noise, by the intensity the emitted from the engine sound waves is reduced. There are different types of automotive silencers, which reduce the sound intensity with different strategies. Basically different passive-acting resonance dampers, Reflection attenuator, absorbing damper and interference attenuators as well as actively acting (counter) silencers. In practice will be usually realized several effects in a muffler housing.

Motor vehicle silencers usually exist from a metallic silencer housing, which with pipes for the inlet and outlet of the exhaust gases is provided. The interior of the muffler housing is made from one room or from several chambers, which are created by screens or baffles separated and over Pipes are interconnected. The inner walls of the silencer housing or the individual chambers can also wear a coating of sound insulation materials, for example Stone or glass wool.

A generic motor vehicle silencer counts by the DE 101 20 974 C1 to the state of the art. There is proposed inter alia, to line the plastic cover of the muffler housing on its inside with an inner lining. The interior lining consists of a sound-absorbing and thermo-insulating material, such as a temperature-resistant felt. In addition to the thermal insulation effect to protect the lid from overheating the inner lining should allow absorption of the pressure pulsation within the muffler housing.

Out JP 4-334714 A is known a small-sized silencer for motorcycles, consisting of an outer tube and a perforated inner tube, the space between the inner tube and the outer tube with a lining of filling material stuffed. Here are different fillers for use. The top and side areas are with glass wool stuffed, whereas introduced at the bottom of steel wool is.

The technological background also includes the US 6 224 440 B1 and the US 4,026,381 which exhaust mufflers with integrated inserts of moisture-absorbing or moisture-repellent materials describe.

The Insulation and Sound characteristics as well as the mechanical resistance of silencers can by Condensate accumulations in the silencer housing are impaired resulting in a reduction of the muffler volume as well as a change the sound impedance and the natural frequency can lead. Because of his aggressive properties, the condensate is also a major cause for corrosion damage to the silencer housing. adversely Furthermore, the deposition of solid substances or material particles in the muffler which changes the reflection and diffusion behavior. Also changing or inhomogeneous gas temperatures lead to a change the reflection and diffusion behavior. Finally, a sound coupling can occur by external structure-borne sound generators or vibrating surfaces with weak damping detrimental to the insulation and sound characteristics as well as mechanical resistance or life of a muffler impact.

The Requirements for modern exhaust systems and the integrated ones silencer are therefore complex. In addition to an efficient noise reduction they should if possible also contribute to the exhaust gas detoxification. In addition, the exhaust gases are safe derived and the performance the engine as possible be little affected. In addition, one strives for a weight-saving and corrosion-resistant construction the muffler at.

Of the Invention is therefore, starting from the prior art, the task to provide a motor vehicle silencer with improved Damper characteristics, high durability, low weight and influence on the exhaust gas quality.

The solution This object is according to the invention in a motor vehicle silencer according to the features in the characterizing part of claim 1.

After that It is envisaged that the interior lining will have two trim areas having a first top cladding area is provided which consists of a moisture-repellent textile fabric made of synthetic fibers and a 2nd floor cladding area is provided, which from a moisture-absorbing textile sheet made of synthetic fibers.

The inner lining according to the invention enables the insulation of the air-borne noise Wech Interaction and the reduction of airborne sound by energy absorption by means of sound-absorbing textiles, the dedusting and catalytic purification of the exhaust gas and the drying of the muffler by the use of moisture-absorbing synthetic fibers. In particular, synthetic fiber nonwovens are used. These are textile fabrics of individual synthetic fibers, preferably of polyacrylonitrile fibers. These have high thermal stability and high chemical and hydrolytic resistance. Due to a high LOI value (limiting oxygen index) of about 50% (O ₂ ), the so-called oxygen index, which indicates the combustibility of plastics in differently composed oxygen-nitrogen mixtures, polyacrylonitrile fibers are in the form of technical textiles especially suitable for thermal and acoustic insulation.

Also Aramid fibers of aromatic polyamides are for use in the invention very suitable. Aramid fibers are characterized by very high strength, high impact strength, high elongation at break, good vibration damping and durability across from acids out and beyond very heat resistant.

The 1st top panel of synthetic fiber fleece is porous or open-pored and can also be coated. It acts as a catalyst and broadband sound absorber for the absorber frequency f ₀ ≈ c / 4d, where "c" is the speed of sound and "d" the layer thickness as the sum of the distance "s" and the thickness of the synthetic fiber web.

In the motor vehicle silencer according to the invention, the exhaust gas is also purified by solid particles which either sink to the bottom due to the reduced flow velocity in the silencer housing or are filtered out of the exhaust gas flow by adhering to the synthetic fibers. The fine dusts oxidize in the muffler climate under changing temperature, humidity and Oxidydmittelver- conditions with time due to the (soot) particles own large surface. Suitable oxidizing agents for carbon black are O ₂ (oxygen) O ₃ (ozone) and NO _x . The time constant for the oxidation of soot by trace oxides of the usual concentration in the exhaust gas or in air concentration at a temperature of 200 ° C is several 100 minutes.

advantageous Embodiments and developments of the basic concept of the invention are Subject of the dependent Claims 2-14.

A Particularly advantageous embodiment of the invention provides that in the silencer housing at least a pipe support made of synthetic fibers. It is therefore a textile pipe support. In particular, there is the pipe support from moisture-absorbing synthetic fibers, preferably from a capillary synthetic fiber fleece. This measure also contributes to the drying of the condensate sump by capillary action and evaporation at. The condensate is from the bottom-side cladding area, as well as absorbed by the pipe support and rises through the capillary of the synthetic fiber fleece to the exhaust outlet, where the synthetic fibers on the principle of a wick through the gas stream be dried. The pipe support supports itself on the 2nd cladding area and extends from this upwards. The pipe support can also be a unit with the 2nd floor cladding area form. tube support and 2nd floor cladding area can (stiffening) parts made of metal.

Of the 1st cladding area is arranged at a distance from the inner wall of the silencer housing. The gap between the silencer housing and the 1st upper-side cladding area serves as an absorber on the one hand and on the other hand can be filled with more insulating material or with components of the measuring and Control technology be provided.

to Achieving a full-surface Lining of the muffler housing is provided that the 1st cladding area and the 2nd cladding area line the silencer housing on all sides. Here, the first cladding area extends over the inner top and side walls of the muffler housing until to the 2nd floor cladding area and closes at this flush at. This measure provides efficient protection of the muffler housing against direct impact the exhaust gas.

in the Silencer housing is further provided at least one aperture made of synthetic fibers, wherein the panel preferably made of moisture-repellent synthetic fibers and possibly reinforced by stiffening elements. The iris is wearing for structure-borne sound insulation, the Dust pickup and catalysis of the exhaust gases at. In addition, she can to Attachment of arranged in the muffler housing pipe components or also parts of an active counter-noise generator (e.g. Speaker) serve.

Especially the aperture is arranged above the pipe support, so that the Aperture and the pipe support form a partition which divides the muffler housing into chambers. (Stiffening) parts of the panel can be made of metal.

Within the silencer housing, a partial perforation connects to the inlet tube tes inlet diffuser tube. Preferably, this consists of steel. Through the inlet diffuser tube, the exhaust gas flow in the muffler housing is slowed down, increases the gas pressure and reduces the muzzle noise.

Further is provided that the outlet pipe within the muffler housing a partially perforated outlet diffuser pipe is connected upstream. The Outlet diffuser tube is preferably made of a fiber composite material. This carries to reduce weight and avoid standing sound waves in the outlet pipe at. Of course The outlet diffuser tube may also be made of metal.

to Attachment of the motor vehicle silencer or the silencer housing on the motor vehicle is on the outside of the muffler housing Fastening element made of elastic synthetic fibers provided. This is connected to the inner lining and through an opening in the top of the muffler housing led to the outside. A Attachment of the motor vehicle silencer by a fastener Synthetic fibers are advantageous because of their high thermal and mechanical properties Stability, which is beneficial to the life of the fastener and thus affects the motor vehicle silencer. It also works the fastener as structure-borne sound insulation between the muffler and the vehicle floor.

A Further weight reduction can be achieved if the muffler housing from a Fiber composite material is produced, in particular from a carbon fiber or aramid fiber reinforced Plastic or composite material.

• – Verbesserung der Korrosionsbeständigkeit und Verlängerung der Nutzbarkeit;
• – Verringerung des Gewichts;
• – Effektiver Schutz der Bauteile gegen die direkte Einwirkung des Gases;
• – Verbesserung der Schalldämmung durch Energieentzug (Diffusion und Absorbtion);
• – Vermeidung von Körperschallbrücken und von Schall-Abstrahlflächen;
• – Vermeidung bzw. Trocknung eines Kondensat-Sumpfes durch Kapillarwirkung und Verdampfung;
• – Verbesserung der Abgasqualität durch Reinigung des Abgases von festen Teilchen.
• – Anwendbar auf aktive (Gegen-)Schalldämpfer und auf passive Schalldämpfer.

The advantages of the motor vehicle silencer according to the invention can be summarized as follows:

• - Improvement of corrosion resistance and extension of usability;
• - reduction of weight;
• - Effective protection of the components against the direct action of the gas;
• - Improvement of sound insulation through energy extraction (diffusion and absorption);
• - avoidance of structure-borne sound bridges and sound radiation surfaces;
• - avoidance or drying of a condensate sump by capillary action and evaporation;
• - Improving the quality of the exhaust gas by cleaning the exhaust gas from solid particles.
• - Applicable to active (counter) silencers and passive silencers.

The Invention is described below with reference to an embodiment.

The drawing shows a motor vehicle silencer according to the invention 1 , The motor vehicle silencer 1 includes a muffler housing 2 in lightweight construction of a fiber composite material, preferably of a carbon fiber or aramid fiber reinforced composite material. The exhaust gas coming from the internal combustion engine is via an inlet pipe 3 made of metal in the silencer housing 2 initiated. Via an outlet pipe 4 the exhaust leaves the muffler housing 2 , The outlet pipe 4 consists of a fiber composite material or metal.

Inside the muffler housing 2 is to the inlet pipe 3 a partially perforated inlet diffuser tube 5 made of metal. Offset to this is a partially perforated outlet diffuser tube 6 intended. This consists of a porous fiber composite material and is inside the muffler housing 2 the outlet pipe 4 upstream.

The silencer housing 2 is with an interior lining 7 Mistake. The interior lining 7 has two cladding areas 8th and 9 on, namely a 1. top panel area 8th and a 2nd floor cladding area 9 , The 1st upper-side fairing area 8th consists of a moisture-repellent textile fabric 10 made of synthetic fibers and extends over the inner top 11 of the muffler housing 2 as well as over the side walls 12 and closes at the 2nd bottom cladding area 9 so that the 1st cladding area 8th and the 2nd cladding area 9 the silencer housing 2 Lining on all sides.

The 2nd floor cladding area 9 consists of a moisture-absorbing textile fabric 13 made of synthetic fibers. This synthetic fiber can absorb up to 10% moisture.

Preferably, both come for the sheet 10 as well as for the fabric 13 Polyacrylonitrile fibers or aramid fibers are used. These have very good thermal and acoustic insulation properties and are also heat resistant up to 320 ° C, a temperature that occurs in an uninsulated metallic exhaust pipe after a few decimeters only in the core flow of the exhaust gas.

The interior lining 7 protects the muffler housing 2 before the direct action of the exhaust gas. In particular, the 1st upper-side cladding area 8th acts as a catalyst and broadband sound absorber for the absorber frequency f ₀ ≈ c / 4d. The fabric 13 on the ground 14 of muffler housing 2 serves for fluid absorption in the silencer housing 2 , Accumulating condensate is in the fabric 13 picked up and dried.

In the silencer housing 2 are in the embodiment shown here a total of three pipe support 15a -C provided. These stand on the fabric 13 on and extend across the entire width of the muffler housing 2 , On the pipe supports 15a -C are the ones in the silencer housing 2 arranged tube fittings, so the inlet diffuser tube 5 and the outlet diffuser tube 6 held.

The pipe supports 15a -C consist of moisture-absorbing synthetic fibers. That of the fabric 13 absorbed condensate can be so by capillary action on the pipe support 15a Ascend and evaporate or be dried on the principle of a wick through the exhaust stream.

Above the pipe support 15a and 15b is each an aperture 16a respectively. 16b arranged. The irises 16a and 16b consist of moisture-repellent synthetic fibers.

The irises 16a respectively. 16b and the pipe supports 15a respectively. 15b form partitions 17 . 18 which the silencer housing 2 in chambers 19 . 20 . 21 divide. As a result, the principles of reflection and resonance are used for sound attenuation. The inlet diffuser pipe 5 and the outlet diffuser tube 6 are staggered to each other, the chambers 19 to 21 are different sizes. In this way, the exhaust gas flow in the muffler housing is deflected several times. When going through the chambers several times 19 - 21 There is a reduction of characteristic sound pressure peaks in the frequency spectrum as well as the overall sound amplitude, which results in a muffled, vehicle-typical sound. Furthermore, in the muffler housing 2 Reflections due to cross-sectional widening or narrowing as well as the perforation of inlet diffuser tube 5 and outlet diffuser pipe 6 generated. In cooperation with the interior lining 7 A broad spectrum of frequencies can be covered so that efficient sound insulation through energy extraction is achieved.

It can be seen further that the 1st cladding area 8th at a distance s to the inner wall 22 of the muffler housing 2 is arranged. This gap s serves as an absorber. It can also be filled with additional insulation material. Furthermore, there components of the measurement and bar technology, such as sensors for measuring the quality of the quantity of exhaust gas as well as for the control of an active (counter) silencer housed.

For fastening the silencer housing 2 on the motor vehicle is on the outside 23 of the muffler housing 2 an eyelet-like fastening element 24 intended. The fastener 24 is also made of synthetic fibers and is covered with the inner lining 7 connected. This is in the top 11 of the muffler housing 2 an opening 25 provided, which of the fastener 24 permeated and sealed gas-tight.

Through the opening 25 and about the fastener 24 can measure, data and supply lines to those in the gap 5 housed components.

1

Automobile mufflers

2

muffler housing

3

inlet pipe

4

outlet pipe

5

Inlet diffuser tube

6

Outlet diffuser tube

7

interior panelling

8th

1.Oberseitiger cladding portion

9

floor-sided cladding portion

10

Fabrics too 8th

11

inner top v. 2

12

Side wall

13

Fabrics too 9

14

Soil v. 2

15a

tube support

15b

tube support

15c

tube support

16a

cover

16b

cover

17

partition wall

18

partition wall

19

chamber

20

chamber

21

chamber

22

Inner wall v. 2

23

Outside v. 2

24

fastener

25

opening

s

distance

Claims (15)

Motor vehicle silencer, which has a silencer housing ( 2 ) with an inlet pipe ( 3 ) and an outlet tube ( 4 ), wherein the muffler housing ( 2 ) with an inner lining ( 7 ), which two cladding areas ( 8th . 9 ), wherein a 1st upper cladding area ( 8th ) and a second floor cladding area ( 9 ), characterized characterized characterized in that the 1st upper-side cladding area ( 8th ) from a moisture-repellent textile fabric ( 10 ) consists of synthetic fibers and the second floor cladding area ( 9 ) from a moisture-absorbing textile fabric ( 13 ) consists of synthetic fibers. Motor vehicle silencer according to claim 1, characterized in that in the silencer housing ( 2 ) at least one pipe support ( 15a -C) is made of synthetic fibers. Motor vehicle silencer according to claim 2, characterized in that the pipe support ( 15a -C) from the 2nd cladding area ( 9 ) extends upward. Motor vehicle silencer according to claim 2 or 3, characterized in that the pipe support ( 15a -C) consists of moisture-absorbing synthetic fibers. Motor vehicle silencer according to at least one of claims 1 to 4, characterized in that the first cladding area ( 8th ) at a distance (s) to the inner wall ( 22 ) of the muffler housing ( 2 ) is arranged. Motor vehicle silencer according to at least one of claims 1 to 5, characterized in that the first cladding area ( 8th ) and the second cladding area ( 9 ) the silencer housing ( 2 ) on all sides. Motor vehicle silencer according to at least one of claims 1 to 6, characterized in that in the silencer housing ( 2 ) at least one aperture ( 16a . 16b ) is provided of synthetic fibers. Motor vehicle silencer according to claim 7, characterized in that the diaphragm ( 16a . 16b ) consists of moisture-repellent synthetic fibers. Motor vehicle silencer according to claim 7 and 8, characterized in that the diaphragm ( 16a . 16b ) above the pipe support ( 15a . 15b ), wherein the diaphragm ( 16a . 16b ) and the pipe support ( 15a . 15b ) a partition wall ( 17 . 18 ), which the silencer housing ( 2 ) in chambers ( 19 . 20 . 21 ). Motor vehicle silencer according to at least one of claims 1 to 9, characterized in that inside the silencer housing ( 2 ) to the inlet pipe ( 3 ) a partially perforated inlet diffuser tube ( 5 ) connected. Motor vehicle silencer according to at least one of claims 1 to 10, characterized in that the outlet pipe ( 4 ) within the muffler housing ( 2 ) a partially perforated outlet diffuser tube ( 6 ) is connected upstream. Motor vehicle silencer according to claim 11, characterized in that the outlet diffuser tube ( 6 ) consists of a fiber composite material. Motor vehicle silencer according to at least one of claims 1 to 12, characterized in that on the outside ( 23 ) of the muffler housing ( 2 ) a fastener ( 24 ) is provided of synthetic fibers, which with the inner lining ( 7 ) connected is. Motor vehicle silencer according to claim 13, characterized in that the fastening element ( 24 ) is provided for gas-tight implementation of measuring, data or supply lines. Motor vehicle silencer according to at least one of claims 1 to 14, characterized in that the silencer housing ( 2 ) consists of a fiber composite material.