DE102009037505A1 - Exhaust manifold for internal combustion engine, comprises exhaust gas collecting housing, and connecting piece for connecting exhaust gas collecting housing with outlet channels of internal combustion engine - Google Patents

Abstract

The exhaust manifold (1) comprises an exhaust gas collecting housing (2), and a connecting piece (3) for connecting the exhaust gas collecting housing with outlet channels of the internal combustion engine. A heat-proof and sound-proof unit (4) is provided, which is attached on the wall of the exhaust gas collecting housing, and has a perforated wall (5).

Description

The invention relates to an exhaust manifold for an internal combustion engine, with an exhaust gas collecting housing and with at least one connecting piece for connecting the exhaust gas collecting housing with exhaust ducts of the internal combustion engine.

From the prior art, a plurality of exhaust manifolds for internal combustion engines is known. Purely by way of example is in this context on the EP 1 389 267 B1 , the DE 100 01 287 A1 or the EP 671 551 A1 directed.

In modern internal combustion engines, a constantly increasing exhaust gas temperature is achieved due to the ever-improving efficiency and higher performance, which has a strong heat radiation of the exhaust manifold in the engine compartment result. An equally big problem is that the exhaust manifold is excited by the engine to vibrate, resulting in a relatively strong noise within the engine compartment. In order to prevent these noises also penetrate into the passenger compartment, usually a very expensive insulation of the engine compartment is provided, which on the one hand is very costly, and on the other hand requires a large space.

It is therefore an object of the present invention to provide an exhaust manifold for an internal combustion engine, in which a reduced heat and noise radiation is achieved in the engine compartment.

According to the invention, this object is achieved by the features mentioned in claim 1.

The heat and sound damping device according to the invention with the perforated wall produces a damping of the structure-borne noise generated by the exhaust manifold, in which the air molecules, which pass through the sound movements in the pores of the perforated wall, are decelerated and converted into heat, resulting in a sound attenuation. By the sound or a force or speed excitation of the exhaust manifold bend waves that deform the exhaust manifold, albeit only to a small extent, and thus lead to the sound radiation through the exhaust manifold. The attached to the exhaust manifold, in particular fixedly connected thereto, the perforated wall according to the present invention generates, in particular in its configuration as a fabric with the existing internal friction, together with the resulting by the attachment of the perforated wall to the exhaust manifold friction between the perforated wall and the exhaust manifold, a high attenuation of this structure-borne sound. Furthermore, an acoustic short circuit results on the surface of the perforated wall, in which the pressure waves excited by the vibrations are compensated within and on the surface of the perforated wall.

Advantageously, the heat and sound damping device according to the invention can be produced very inexpensively, since it is mounted only on a relatively small area, namely on one or more walls of the exhaust manifold. This leads to the further advantage of very small space requirements, which is a great advantage in the confined spaces in engine compartments of modern motor vehicles and is still favored by the very small wall thickness of the porous wall.

At the same time, the heat and sound damping device according to the invention is a heat shield, which thermally insulated the exhaust manifold against adjacent components and thus ensures that the heat emitted from the exhaust manifold is not radiated in the direction in which the heat and sound damping device according to the invention is arranged.

In particular, in the event that plastic parts, such as air filter housing or the like, or electronic components, such as control units, located in the vicinity of the exhaust manifold, such a thermal insulation by means of the heat and sound damping device according to the invention is advantageous.

In a very advantageous development of the invention can be provided that the perforated wall is formed as a fabric with warp wires and weft wires and located between the warp wires and weft wires pores. Such a fabric can be made very easily and quickly, whereby the cost of the fabric can be kept low. Since very thin wires can be used for such a fabric, it is possible to form a very thin and thus extremely flexible and space-saving perforated wall of the heat and sound damping device.

When a fabric is used as the perforated wall, the pores formed between the warp wires and the weft wires and between the weft wires provide for absorption of the sound entering the pores, thereby converting the sonic energy of the sound into heat energy and thus dampening the sound so that the fabric forms an acoustically effective absorber. The absorption, the sound is going through generates the deflections of the sound waves within the tissue and by the friction in the boundary layer of the tissue, which represent a resistance to the sound waves. Here, a higher flow resistance of the tissue produces a higher damping, so there is a direct relationship between the flow resistance of the tissue and the sound absorption. The sound absorption can be influenced by a reduction of the pore size or a reduction of the distance of the weft and / or warp wires.

Such a reduction of the pore size can also be achieved in an advantageous development of the invention in that the fabric is rolled.

Alternatively to the use of a fabric, the heat and sound damping device may also be formed by a slotted expanded metal sheet or by a microperforated sheet. Also, such a heat and sound damping device can be produced very easily and inexpensively and offers, at least for certain applications, a sufficient damping of the radiated from the exhaust manifold sound and emanating from the exhaust manifold heat.

In a very advantageous embodiment of the invention can be provided that the heat and sound damping device is welded to the exhaust manifold. Such welding is a very simple process, which also offers high process reliability. Furthermore, the structure-borne sound is better introduced into the structure of the heat and sound damping device, in particular in the tissue in this way.

The heat and sound damping device can be particularly easily connected to the exhaust gas collecting housing by spot welding.

Alternatively, however, the heat and sound damping device can also be glued to the exhaust gas collecting housing, soldered, screwed, clamped, joined and / or riveted.

In order to simplify the connection of the heat and sound damping device to the exhaust gas collecting housing, it can be provided in a very advantageous development of the invention that the exhaust gas collecting housing has at least one substantially planar contact surface for the heat and sound damping device.

Depending on the design of the exhaust manifold and its location within the engine compartment, the heat and sound damping device may be arranged only on one side or on at least two sides of the exhaust gas collecting housing. This results in different heat and sound damping effects, so that almost any requirements can be met for a damping of emanating from an exhaust manifold heat or sound.

In order to absorb the expected due to the high temperatures of the exhaust manifold thermal expansion, it can be provided in a further advantageous embodiment of the invention that the heat and sound damping device has a plurality of perforated walls.

Further advantageous embodiments and modifications of the invention will become apparent from the remaining dependent claims. Hereinafter, an embodiment of the invention with reference to the drawing is shown in principle.

It shows:

1 a side view of the exhaust manifold according to the invention;

2 a plan view of the exhaust manifold according to the arrow II 1 ;

3 another side view of the exhaust manifold according to the arrow III 2 ;

4 a perspective view of the exhaust manifold;

5 another perspective view of the exhaust manifold;

6 a plan view of a designed as a fabric perforated wall of the heat and sound damping device;

7 a view according to the arrow VII from 6 ;

8th a section along the line VIII-VIII 6 ;

9 a section along the line IX-IX 8th ,

The 1 to 5 show different views of an exhaust manifold 1 for an internal combustion engine, not shown. The exhaust manifold 1 has an exhaust manifold 2 and several connecting pieces 3 for connecting the exhaust gas collecting housing 2 with not shown exhaust ducts of the internal combustion engine. In the present case there are a total of five connecting pieces 3 shown, depending on the number and arrangement of cylinders and in Depending on the design of the internal combustion engine, however, also a different number of connecting pieces 3 be provided.

To that of the exhaust manifold 1 and in particular the exhaust manifold 2 same generated structure-borne noise and due to the high temperatures of the exhaust manifold 1 flowing exhaust gas generated to attenuate heat radiation is at least one wall of the exhaust gas collecting housing 2 a heat and sound damping device 4 arranged. In the present case, the heat and sound damping device 4 on a total of three walls of the exhaust manifold housing 2 , namely on two side walls and the connecting piece 3 facing away, upper wall attached. Depending on the sound and heat radiation as well as installation location within an engine compartment, in which the with the exhaust manifold 1 equipped internal combustion engine is installed, the heat and sound damping device 4 even on a smaller or larger number of walls of the exhaust manifold housing 2 be provided. Optionally, the heat and sound damping device 4 also on only one wall or on one side of the exhaust gas collecting housing 2 be arranged. Because of that in the 3 shown side of the exhaust manifold housing 2 in a relatively large area, the heat and sound damping device 4 not provided, the heat can be on this side of the exhaust manifold 2 outflow, so that a heat accumulation is avoided.

The heat and sound damping device 4 has at least one perforated wall 5 on, in the present case, several perforated walls 5 are provided, the individual sections of the heat and sound damping device 4 form, so that the thermal expansion of the exhaust gas header 2 is not affected. The single perforated walls 5 can either have a certain distance from each other or, which is preferable to overlap, resulting in a better coverage of the relevant areas of the exhaust manifold 1 is achieved and on the other a certain friction between the individual perforated walls 5 adjusts, which is reduced in addition to sound energy.

The perforated wall 5 the heat and sound damping device 4 can with the exhaust manifold 2 be welded, in particular a connection by means of spot welding offers. Instead of a spot welding process, MIG, MAG and other welding processes can be used. Alternatively or additionally, the heat and sound damping device 4 with the exhaust manifold 2 also glued, soldered, screwed, riveted or connected in any other suitable manner. In particular, in the case of a spot welding, it makes sense, at the exhaust manifold 2 a respective, substantially planar contact surface 6 to create the perforated wall 5 the heat and sound damping device 4 suitably and with a high process reliability at the exhaust manifold 2 to be able to attach. Such a contact surface 6 Already when pouring the exhaust manifold 1 be provided on the same and optionally in the mechanical processing, for example, the connection piece 3 also be edited to improve their flatness. Through the contact surfaces 6 Furthermore, an improved degradation of structure-borne noise is achieved, so it is preferable if the exhaust manifold 2 a larger number of contact surfaces 6 as shown in the figures.

At the perforated wall 5 It may be a microperforated sheet metal, a slotted expanded metal sheet or a in the 6 to 9 represented tissue 7 act, which warp or warp wires 8th , Weft threads or weft wires 9 and between the warp wires 8th and the weft wires 9 located pores 10 having. As seen from the top view 6 It can be seen that the warp wires are running 8th essentially perpendicular to the weft wires 9 ,

In the pores 10 the sound velocity energy of the on the perforated wall 5a The sound is converted into heat, absorbing the sound waves. This should be the size of the pores 10 be as small as possible to the size of the perforated wall 5a adjoining air boundary layer, so that the air molecules in the pores 10 braked and the sound energy is converted into heat. In the present case, the size of the air boundary layer is about 0.05 mm, the size of the pores about 0.025 mm. The diameter of the in 9 again with the pores shown weft wires 9 is in the present case about 0.4 mm.

For the production of the fabric 7 will the warp 8th and the weft wires 9 woven together with a per se known weaving method, such as a weaving method for producing a twill weave or a so-called "smooth lace", wherein it should be emphasized that almost all known weaving methods can be used. The material of the warp wires 8th and the weft wires 9 may be, for example, a steel material, a stainless steel or a ceramic. When using a steel material, it is possible to use the entire perforated wall 5 , in this case the tissue 7 to coat with an aluminum layer. Preferably, the warp wires 8th and the weft wires 9 from the same material, but it can also be used different material, ie it is also a combination of plastic and metal or any other combination of the above materials possible. In an embodiment, not shown, the warp wires 8th and / or the weft wires 9 Also have several individual wires to achieve a higher friction.

In the present case, the tissue 7 rolled and therefore has a reduced thickness. It has been shown that by reducing the thickness of the fabric 7 , preferably by rolling in a calender roll or the like, the strength and cohesion of the fabric 7 can be significantly increased. Furthermore, in this way, the size of the pores 10 influenced, in particular reduced.

Although the one heat and sound attenuation device 4 always above with the perforated wall 5 has been described, it is also conceivable, one or more massive steel sheets as a heat and sound damping device 4 to achieve reduced heat and noise emission of an exhaust manifold into the engine compartment. Also a combination of one or more perforated walls 5 with one or more solid steel sheets is conceivable.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1389267 B1 [0002]
• DE 10001287 A1 [0002]
• EP 671551 A1 [0002]

Claims (15)

Exhaust manifold for an internal combustion engine, with an exhaust gas collecting housing and with at least one connecting piece for connecting the exhaust gas collecting housing with exhaust ducts of the internal combustion engine, characterized in that at least one wall of the exhaust gas collecting housing ( 2 ) a heat and sound damping device ( 4 ), which has a perforated wall ( 5 ) having. Exhaust manifold according to claim 1, characterized in that the perforated wall ( 5 ) as a tissue ( 7 ) with warp wires ( 8th ) and weft wires ( 9 ) and between the warp wires ( 8th ) and the weft wires ( 9 ) pores ( 10 ) is trained. Exhaust manifold according to claim 2, characterized in that the tissue ( 7 ) is rolled. Exhaust manifold according to claim 1, characterized in that the perforated wall ( 5 ) is formed as a slotted expanded metal sheet. Exhaust manifold according to claim 1, characterized in that the perforated wall ( 5 ) is formed as a microperforated sheet. Exhaust manifold according to one of claims 1 to 5, characterized in that the heat and sound damping device ( 4 ) with the exhaust gas collection housing ( 2 ) is welded. Exhaust manifold according to claim 6, characterized in that the heat and sound damping device ( 4 ) with the exhaust gas collection housing ( 2 ) is spot-welded. Exhaust manifold according to one of claims 1 to 5, characterized in that the heat and sound damping device ( 4 ) with the exhaust gas collection housing ( 2 ) glued, soldered, screwed, clamped, joined and / or riveted. Exhaust manifold according to one of claims 1 to 8, characterized in that the exhaust gas collecting housing ( 2 ) at least one substantially planar contact surface ( 6 ) for the heat and sound damping device ( 4 ) having. Exhaust manifold according to one of claims 1 to 9, characterized in that the heat and sound damping device ( 4 ) consists of a steel material. Exhaust manifold according to claim 10, characterized in that the heat and sound damping device ( 4 ) is coated with an aluminum layer. Exhaust manifold according to claim 10 or 11, characterized in that the heat and sound damping device ( 4 ) consists of stainless steel. Exhaust manifold according to one of claims 1 to 12, characterized in that the heat and sound damping device ( 4 ) only on one side of the exhaust gas collecting housing ( 2 ) is arranged. Exhaust manifold according to one of claims 1 to 12, characterized in that the heat and sound damping device ( 4 ) on at least two sides of the exhaust gas header housing ( 2 ) is arranged. Exhaust manifold according to one of claims 1 to 14, characterized in that the heat and sound damping device ( 4 ) several perforated walls ( 5 ) having.

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