COMPRESSOR OF AN EXHAUST-GAS TURBOCHARGER
A compressor (8) of an exhaust-gas turbocharger (1), having a compressor wheel (11) which can be driven in a compressor wheel direction of rotation (VR); having a compressor housing (10) in which the compressor wheel (11) is arranged, as viewed in the flow direction of the inducted air, between a preferably tubular compressor inlet (12) and a compressor outlet (13), and having an overrun air recirculation valve inflow duct (14, 15) which runs in the compressor housing (10) from the compressor outlet (13) to the compressor inlet (12), wherein the inflow duct (14, 15) opens into the compressor inlet (12) substantially in the circumferential direction with respect to the inner diameter (DI) of said compressor inlet (12).
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The invention relates to a compressor of an exhaust-gas turbocharger, as per the preamble of claim 1.
In the generic compressor which is provided with an overrun air recirculation valve, the compressor housing has an inflow duct which runs from the compressor outlet to the compressor inlet. Said inflow duct is controlled by the overrun air recirculation valve in order, during operation of the exhaust-gas turbocharger, to prevent a pumping effect which may for example arise when, on account of a braking process of the motor vehicle, the throttle flap is closed but the exhaust-gas turbocharger would still run at high rotational speed. In this situation, to prevent the stated effect, the overrun air recirculation valve is opened and air is conducted from the compressor outlet, or the pressure side, to the compressor inlet, so as to ensure a continuous flow through the compressor wheel without a significant pressure build-up.
In the already known design, the inflow duct runs into the compressor inlet radially, which means that the inflow is directed toward the center of the shaft of the exhaust-gas turbocharger.
Tests carried out within the context of the invention with said design of a known exhaust-gas turbocharger have shown that, on account of the stated opening of the inflow duct radially with respect to the shaft as a result of the inflow direction to the compressor wheel, flow noise is generated which can lead to undesired noise disturbance during the operation of a vehicle provided with an exhaust-gas turbocharger of said type.
In contrast, it is an object of the present invention to provide a compressor of the type specified in the preamble of claim 1, which compressor makes it possible to avoid or considerably reduce the explained flow noises, and also dampen any occurring resonances.
Said object is achieved by means of the features of claim 1.
According to said claim, the inflow duct is arranged in the compressor housing in such a way as to open into the compressor inlet at least in the circumferential direction with respect to a tube inner diameter of the tubular compressor inlet. Said opening may also be referred to as an at least substantially tangential opening, which leads to a tangential inflow, or an inflow directed in the circumferential direction, of the air recirculated from the pressure side into the inducted air, which inflow has at least substantially no disruptive influence on the compressor wheel and therefore reduces the flow noises explained in the introduction at least to such an extent that the noises are practically no longer perceptible.
The inflow directed substantially in the circumferential direction may also have an axial component directed in the flow direction in order to reduce inflow losses.
For this purpose, the compressor inlet may be provided with a cylindrical or frustoconical inflow section into which the inflow duct opens in the way explained above.
The subclaims relate to advantageous refinements of the invention.
In a particularly preferred embodiment, the inflow duct opens into the compressor inlet in such a way that the inflow of the recirculated air leads in the direction of rotation of the compressor wheel. An inflow counter to the direction of rotation of the compressor wheel is, however, also possible in principle.
Further details, advantages and features of the present invention will emerge from the following description of exemplary embodiments on the basis of the drawing, in which:
Furthermore, a turbine wheel 5 is arranged in the turbine housing 2, which turbine wheel is fastened to a shaft 6.
A multiplicity of blades, of which only the blade 7 is shown, is arranged in the turbine housing 2 between the exhaust-gas inlet opening 3 and the turbine wheel 5.
Furthermore, the exhaust-gas turbocharger 1 has a compressor 8, the compressor housing 10 of which is in the usual way connected via a bearing housing 9 to the turbine housing 2. In the compressor housing 10, a compressor wheel 11 is fastened to the second end of the shaft 6. The details of the compressor 8 according to the invention will be explained below on the basis of
The embodiment according to
In
The dash-dotted parallel lines which are additionally shown in
Aside from the written disclosure of the invention, reference may additionally be made to the graphic illustration thereof in
- 1 Exhaust-gas turbocharger
- 2 Turbine housing
- 3 Exhaust-gas inlet opening
- 4 Exhaust-gas outlet opening
- 5 Turbine wheel
- 6 Shaft
- 7 Blade
- 8 Compressor
- 9 Bearing housing
- 10 Compressor housing
- 11 Compressor wheel
- 12 Compressor inlet
- 13 Compressor outlet
- 14 Overrun air recirculation valve inflow duct
- 15 Overrun air recirculation valve inflow duct
- 15a, b Duct sections
- 16 Duct opening
- ZK Inflow duct of the prior art
- VR Direction of rotation of the compressor wheel 11
- DI Inner diameter of the compressor inlet 12
Claims
1. A compressor (8) of an exhaust-gas turbocharger (1),
- having a compressor wheel (11) which can be driven in a compressor wheel direction of rotation (VR);
- having a compressor housing (10) in which the compressor wheel (11) is arranged, as viewed in the flow direction of the inducted air, between a compressor inlet (12) and a compressor outlet (13), and
- having an overrun air recirculation valve inflow duct (14, 15) which runs in the compressor housing (10) from the compressor outlet (13) to the compressor inlet (12), wherein
- the inflow duct (14, 15) opens into the compressor inlet (12) substantially in the circumferential direction with respect to the inner diameter (DI) of said compressor inlet (12).
2. The compressor as claimed in claim 1, wherein the inflow duct (15) opens into the compressor inlet (12) in such a way that the inflow of air takes place in the direction of rotation (VR) of the compressor wheel (11).
3. The compressor as claimed in claim 1, wherein the inflow duct (14) opens into the compressor inlet (12) in such a way that the inflow of air takes place counter to the direction of rotation (VR) of the compressor wheel (11).
4. The compressor as claimed in claim 1, wherein the inflow duct (14) opens into the compressor inlet (12) in such a way that the inflow of air has an axial component in the flow direction.
5. The compressor as claimed in claim 1, wherein compressor inlet (12) is tubular.
Type: Application
Filed: Apr 20, 2011
Publication Date: Feb 21, 2013
Applicant: BORGWARNER INC. (Auburn Hills, MI)
Inventor: Udo Dellmann (Lohnsfeld)
Application Number: 13/643,097
International Classification: F04D 17/10 (20060101);