CH712704A2 - Turbocharger. - Google Patents

Abstract

A turbocharger having a turbine for relaxing a first medium and recovering energy in the expansion of the first medium, and a compressor for compressing a second medium using the energy recovered in the turbine, wherein at least one flow guiding element of the turbocharger with a muffler (1) is provided, wherein the respective muffler (1) has a support structure (3) with a support wall (4) and formed on the support wall (4) chambers (5), wherein the chambers (5) on one of a flow channel (7) of the muffler (1) facing away from the same by the support wall (4) are limited, and wherein the chambers (5) on a flow channel (7) of the muffler (1) facing side thereof are bounded by a cover (8) , wherein the cover (8) has at least two grid-like layers (9, 10, 11) with different mesh widths fixedly connected to one another.

Description

Description: The invention relates to a turbocharger.

From DE 19 818 873 C2 a reciprocating internal combustion engine with at least one exhaust gas turbocharger is known. At least one flow-carrying element of the exhaust gas turbocharger is assigned a silencer, which is based on the principle of a Helmholtz resonator. The respective muffler has a support structure consisting of an outer support wall and a plurality of chambers accommodated by the support wall, the chambers being delimited by a perforated plate on a side of the muffler facing a flow channel.

The known from the prior art use of silencers, which are based on the principle of a Helmholtz resonator, has the disadvantage that, due to the principle, only a very limited frequency range can be effectively attenuated. At frequencies outside this frequency range, the damping effect decreases significantly.

Based on this, the present invention seeks to provide a novel turbocharger with improved noise reduction.

This object is achieved by a turbocharger according to claim 1. According to the invention, the cover has at least two firmly connected, grid-shaped layers with different mesh sizes.

In the exhaust gas turbocharger according to the invention, the cover of the respective muffler is designed in multiple layers, the cover having at least two firmly interconnected, lattice-shaped layers with different mesh sizes. In this way, a silencer with an improved sound damping effect can be provided. In particular, the muffler with such a cover has a better damping effect over a wider frequency range.

According to an advantageous development of the invention, the grid-shaped layers of the cover are formed with the different mesh sizes of wire mesh, the wire mesh of the individual layers not only having different mesh sizes but also different wire diameters. This can provide a particularly advantageous sound damping effect.

Preferably, the cover has a thickness t, the chambers having a depth a defined by the distance of the cover from the support wall, where t is less than a. This serves to provide a particularly advantageous sound damping effect.

In particular, a ratio t / a between the thickness t of the cover and the depth a of the chambers is between 0.2 and 0.025. These details also serve to provide a particularly advantageous sound damping effect.

According to an advantageous development, a ratio a / λ between the depth a of the chambers and a sound wavelength λ of the frequency to be damped is between 0.25 and 0.4. This can further improve the sound damping effect.

According to an advantageous development, the respective silencer is integrated in the respective flow-guiding element of the turbocharger, preferably in a spiral discharge housing of the compressor. The integration of the muffler in a spiral outflow housing of the compressor is particularly preferred, since a particularly good sound damping effect can be provided as a result with a minimal space requirement.

According to an advantageous development, the chambers of the support structure have alternately different widths when viewed in the flow direction of a flow channel of the muffler. This can further improve the sound damping effect.

Further developments of the invention result from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being restricted to this. It shows:

1: a schematic cross section through a muffler of a turbocharger according to the invention;

Fig. 2: the detail II of Fig. 1 in a perspective view.

[0014] The present invention relates to a turbocharger. The basic structure of a turbocharger is familiar to the expert addressed here. For example, a turbocharger has a turbine for expanding a first medium, in particular for expanding exhaust gas, in which case energy is obtained. Furthermore, a turbocharger comprises a compressor for compressing a second medium, in particular for compressing charge air, in which case energy is used in the compressor that was obtained in the turbine when the first medium was expanded.

[0015] A turbocharger has different flow-carrying assemblies. In particular, this includes a so-called outflow housing of the compressor of the exhaust gas turbocharger. At least one flow-guiding element of the turbocharger is provided with a silencer 1.

CH 712 704 A2 Fig. 1 shows a schematic cross section through a silencer 1 which interacts with a flow-guiding element of the turbine, for example with the spiral outflow housing of the compressor of the turbocharger.

1 has flanges 2 through which the muffler 1 can be screwed to other flow-carrying components of the turbocharger. 1 is therefore a separate assembly of the turbocharger, which is screwed to other assemblies of the same.

The muffler 1 has a supporting structure 3 with a supporting wall 4 and with chambers 5 formed on the supporting wall 4. The supporting wall 4 is, in particular, a radially outer tube. On this radially outer tube, which provides the supporting wall 4, chambers 5 are formed, which are formed by metal sheets 6, which extend essentially in the radial direction of the supporting wall 4, or are delimited from one another.

Radially inside the chambers 5 of the support structure 3 is adjacent to a flow channel 7 of the muffler 1, which is flowed through by a sound-absorbing medium.

As already mentioned, the chambers 5 are delimited on a side facing away from the flow channel 7 by the supporting wall 4. The chambers 5 of the support structure 3 are delimited by a cover 8 on a side facing the flow channel 7.

The cover 8 has at least two firmly connected, grid-shaped layers with different mesh sizes. 1 and 2, a cover 3 is shown from three firmly connected, lattice-shaped layers 9, 10 and 11, each having different mesh sizes.

Particularly preferably, the lattice-shaped layers 9, 10 and 11 of the cover 8, which have the different mesh sizes, are each provided by a wire mesh, these wire meshes of the individual layers 9, 10 and 11 preferably not only having different mesh sizes but also different wire diameters exhibit.

Fig. 1 can be seen that the chambers 5 of the support structure 3 in the radial direction have a depth a, which is defined by the distance of the cover 8 from the support wall 4. 2 has a radial thickness t. The thickness t of the cover 8 is smaller than the depth a of the chambers 5.

A ratio t / a between the thickness t of the cover 8 and the depth a of the chambers 5 is preferably between 0.2 and 0.025.

Seen in the flow direction of the flow channel 7 of the silencer 1, the chambers 5 of the support structure 3 have a width b, in FIG. 1 the chambers 5 of the support structure 3 each have alternately different widths b in the flow direction of the flow channel 7.

According to a particularly preferred embodiment, a ratio a / λ between the depth a of the chambers 5 of the support structure 3 and a sound wavelength λ of the frequency to be damped is between 0.25 and 0.4.

In this case, a ratio Rs / Z ₀ between the acoustic specific flow resistance Rs and the sound characteristic impedance Z _{o of} the medium to be damped with regard to its sound noise is between 0.25 and 4. The acoustic specific flow resistance Rs for turbocharger compressors is between 350 and 5500 Pa * s / m. The depth a of the chambers 5 of the support structure 3 is particularly preferably between 15 mm and 90 mm.

In the embodiment of Fig. 1, the silencer 1 is designed as a separate assembly and connected via the flanges 2 with another flow-carrying element of the turbocharger.

In contrast to this, it is also possible to integrate the muffler 1 in a flow-guiding element of the turbocharger, particularly preferably in a flow-guiding, spiral-like outflow housing of the compressor of the turbocharger.

The muffler 1 acts like a λ / 4 resonator and has a good sound damping effect over a wide frequency range.

Reference symbol list [0032]

silencer

flange

supporting structure

supporting wall

chamber

CH 712 704 A2

sheet

flow channel

cover

location

location

location

Claims (11)

claims 1. Turbocharger, with a turbine for relaxing a first medium and for generating energy when relaxing the first medium, and with a compressor for compressing a second medium using the energy obtained in the turbine, with at least one flow-carrying element of the turbocharger A silencer (1) is provided, the respective silencer (1) having a support structure (3) with a support wall (4) and with on the support wall (4) formed chambers (5), the chambers (5) on one are delimited from a flow channel of the muffler side thereof by the support wall (4), and wherein the chambers (5) are delimited by a cover (8) on a side thereof facing the flow channel (7) of the muffler, characterized in that the Cover (8) has at least two firmly connected, grid-shaped layers (9, 10, 11) with different mesh sizes. 2. Turbocharger according to claim 1, characterized in that the grid-shaped layers (9, 10, 11) of the cover (8) are formed with the different mesh sizes of wire meshes, the wire meshes of the individual layers not only having different mesh sizes but also different wire diameters , 3. Turbocharger according to claim 1 or 2, characterized in that the cover (8) has a thickness t, that the chambers (5) have a depth a defined by the distance of the cover (8) from the support wall (4), wherein t is less than a. 4. Turbocharger according to claim 3, characterized in that a ratio t / a between the thickness t of the cover (8) and the depth a of the chambers (5) is between 0.2 and 0.025. 5. Turbocharger according to claim 3 or 4, characterized in that a ratio A / A between the depth a of the chambers (5) and a sound wavelength λ of the frequency to be damped is between 0.25 and 0.4. 6. Turbocharger according to one of claims 3 to 5, characterized in that the depth a of the chambers (5) of the support structure (3) is between 15mm and 90mm. 7. Turbocharger according to one of claims 1 to 6, characterized in that the respective silencer (1) is integrated in the respective flow-guiding element of the turbocharger. 8. Turbocharger according to claim 7, characterized in that the respective silencer (1) is integrated in a spiral outflow housing of the compressor of the turbocharger. 9. Turbocharger according to one of claims 1 to 6, characterized in that the respective silencer (1) is designed as a separate assembly and is connected to the respective flow-guiding element of the turbocharger. 10. Turbocharger according to one of claims 1 to 9, characterized in that a ratio Rs / Z ₀ between the acoustic specific flow resistance R _s and the acoustic characteristic impedance Z _{o of} the flowing medium is between 0.25 and 4. 11. Turbocharger according to one of claims 1 to 10, characterized in that the chambers (5) of the support structure (3) in the flow direction of a flow channel (7) of the silencer (1) alternately have different widths b. CH 712 704 A2