Compressor of a turbocharger having an air recirculation valve and turbocharger and motor vehicle having such a compressor

Abstract

A compressor of a turbocharger is provided. The compression pipe of the compressor is connected to the intake pipe thereof by a return flow duct, in which an air recirculation valve is arranged for controlling the return flow of already compressed fresh air. The return flow duct opens into a groove of an intake manifold receptacle of the compressor, and at least one return flow opening adjoining the groove and facing an interior of the intake pipe is arranged on an intake manifold of the intake pipe.

Claims

1. A compressor of a turbocharger, comprising: a compression pipe; an intake pipe; a return-flow duct connecting the compression pipe and the intake pipe, wherein a compression pipe end of the return flow duct is located in a compressor housing at a compressor wheel end of the compression pipe, and the return duct is configured to conduct return flow of already-compressed fresh air from the compression pipe to a location in the intake pipe upstream of an inlet end of the compressor wheel; and an overrun air recirculation valve arranged in the return-flow duct that controls the return flow of the already-compressed fresh air from the compression pipe to a location in the intake pipe, wherein the return-flow duct opens into a groove of an intake connector receptacle of the compressor, the intake connector receptacle being configured to receive an intake connector at a location in the intake pipe radially inward of the groove, and the groove is configured to pass the return flow radially inward through at least one return-flow opening in the intake connector to an interior space of the intake pipe upstream of the inlet end of the compressor wheel.

2. The compressor as claimed in claim 1, wherein the groove is arranged along an entire circumference of the intake connector receptacle.

3. The compressor as claimed in claim 1, wherein the groove is formed as a ring-shaped groove proceeding from an inner circumferential surface of the intake connector receptacle.

4. The compressor as claimed in claim 1, wherein the groove is arranged along a part of a circumference of the intake connector receptacle.

5. The compressor as claimed in claim 1, wherein the at least one return-flow opening includes a plurality of the return-How openings positioned in the intake connector.

6. The compressor as claimed in claim 5, wherein the plurality of the return-flow openings are arranged in a circumference of the intake connector at locations with a same pressure potential of inducted fresh air during operation of the turbocharger.

7. The compressor as claimed in claim 1, wherein the intake connector has a larger inner diameter in the region of the return-flow opening than in an adjacent region along an axis of rotation of the compressor wheel of the compressor which is remote from the compressor wheel.

8. The compressor as claimed in claim 1, wherein the intake connector has a separation edge upstream of the return-flow opening with respect to a main intake direction in the intake pipe.

9. The compressor as claimed in claim 1, wherein the return-flow duct is arranged at least partially offset with respect to a return-flow opening.

10. The compressor as claimed in claim 1, wherein the return-flow opening is a bore in a wall of the intake connector.

11. The compressor as claimed in claim 1, wherein the return-flow opening is, at least over a part of its radial extent, formed so as to be open toward a compressor-wheel-side face side of the intake connector.

12. A turbocharger, comprising: a compressor having a compression pipe; an intake pipe; a return-flow duct connecting the compression pipe and the intake pipe, a compression pipe end of the return flow duct being located in a compressor housing at a compressor wheel end of the compression pipe, and the return duct is configured to conduct return flow of already-compressed fresh aft from the compression pipe to a location in the intake pipe upstream of an inlet end of the compressor wheel; and an overrun air recirculation valve arranged in the return-flow duct that controls return flow of the already-compressed fresh air from the compression pipe to a location in the intake pipe, wherein the return-flow duct opens into a groove of an intake connector receptacle of the compressor, the intake connector receptacle being configured to receive an intake connector at a location in the intake pipe radially inward of the groove, and the groove is configured to pass the return flow radially inward through at least one return-flow opening in the intake connector to an interior space of the intake pipe upstream of the inlet end of the compressor wheel.

13. A motor vehicle, comprising: a turbocharger having a compressor, the compressor having a compression pipe; an intake pipe; a return-How duct connecting the compression pipe and the intake pipe, wherein a compression pipe end of the return flow duct is located in a compressor housing at a compressor wheel end of the compression pipe, and the return duct is configured to conduct return flow of already-compressed fresh air from the compression pipe to a location in the intake pipe upstream of an inlet end of the compressor wheel; and an overrun air recirculation valve arranged in the return-flow duct that controls the return flow of the already-compressed fresh aft from the compression pipe to a location in the intake pipe, wherein the return-flow duct opens into a groove of an intake connector receptacle of the compressor, the intake connector receptacle being configured to receive an intake connector at a location in the intake pipe radially inward of the groove, and the groove is configured to pass the return flow radially inward through at least one return-flow opening in the intake connector to an interior space of the intake pipe at upstream of the inlet end of the compressor wheel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a compressor as per a first embodiment of the invention in a partially schematic sectional view.

(2) FIG. 2 shows a compressor as per a second embodiment of the invention in a partially schematic sectional view.

(3) FIG. 3 shows the arrangement of two return-flow openings on the circumference of the intake connector in a manner dependent on the pressure conditions in the intake pipe in a schematic view.

DETAILED DESCRIPTION OF THE DRAWINGS

(4) FIG. 1 shows the compressor 1 of a turbocharger 2 with the components of the turbocharger 2 surrounding the compressor 1, and with a part of a compression pipe 4 of a compression side 6 of the compressor 1 and a part of an intake pipe 8 of an intake side 10. Between an interior 11 of the compression pipe 4 and an interior 12 of the intake pipe 8 there is formed a return-flow duct 14 which opens into a groove 16 of an intake connector receptacle 18 of the compressor 1.

(5) An intake connector 20 composed of a plastics material is received in the intake connector receptacle 18, which intake connector 20 has two return-flow openings 22.1 and 22.2 via which the groove 16 is connected to the interior 12 of the intake pipe 8. Furthermore, a separation edge 24 is arranged on an inner circumference of the intake connector 20.

(6) Also arranged on the compressor 1 is an overrun air recirculation valve 30 with a valve flap 32 which, during compressor operation, seals off the interior 11 of the compression pipe 4 and the return-flow duct 14 with respect to one another in gas-tight fashion. The compressor 1 furthermore has a compressor wheel 26 which is mounted in the turbocharger 2 for rotation about the longitudinal axis L and which can be driven by a turbocharger wheel (not illustrated) in the exhaust-gas discharge line.

(7) During operation of the turbocharger 2, fresh air is inducted into the interior 12 of the intake pipe 8 from the surroundings by the negative pressure generated by means of the compressor wheel, and the fresh air is introduced, having been compressed at the compressor wheel 26, that is to say at relatively high pressure, into the spiral 28 and from there into the interior 11 of the compression pipe 4.

(8) When the throttle flap of the turbocharged engine (not illustrated) is closed, in order that a pressure high enough for undesired braking of the compressor wheel 26 does not form in the compression pipe 4 as a result of continuing compression via the compressor wheel 26, it is possible in overrun operation for the interior 11 of the compression pipe 4 to be short-circuited to the interior 12 of the intake pipe 8 via the return-flow duct 14 by operation of the overrun air recirculation valve 30. For this purpose, the valve element 32 is moved into an open operating position, in which it opens up the connection between the interior 11 of the compression pipe 4 and the return-flow duct 14.

(9) Here, a fresh-air circuit is formed which runs from the intake connector 20 via the compressor wheel 26, the spiral 28, the compression pipe 4, the return-flow duct 14, the groove 16 and the return-flow openings 22.1 and 22.2 back to the intake connector 20.

(10) The actuation of the overrun air recirculation valve 30 (or of the valve element 32 thereof) may be realized in a wide variety of ways known to a person skilled in the art, for example by coupling to the controller of the throttle flap or by actuation in a manner dependent on an absolute pressure value in the interior 11 of the compression pipe 4 or in a manner dependent on a pressure difference between the compression pipe 4 and the intake pipe 8.

(11) If the valve element 32 is opened in the presence of an elevated pressure in the interior 11 of the compression pipe 4, already-compressed fresh air flows with high kinetic energy (corresponding to the large pressure difference between the intake pipe 8 and the compression pipe 4) into the groove 16 via the return-flow duct 14. The groove 16 is formed as a ring-shaped groove on an encircling circumferential section of the intake connector receptacle 18.

(12) The return-flow openings 22.1 and 22.2 are arranged so as to be circumferentially offset with respect to the inlet point of the return-flow duct 14 into the groove 16, such that, in any case, a preferably turbulent diversion of the return flow occurs on an outer wall of the intake connector 20. The return flow can in this case be distributed in the groove 16 along the entire circumference of the intake connector receptacle 18 and subsequently emerge into the interior 12 of the intake pipe 8 at the return-flow openings 22.1 and 22.2, in particular with relatively low kinetic energy.

(13) As a result, the return flows emerging from the return-flow openings 22.1 and 22.2 and the intake flow in the intake pipe to the compressor wheel impinge on one another with relatively low kinetic energy, such that reduced flow noise arises.

(14) This quiet merging of the air flows is assisted by the separation edge 24 which is arranged on the intake connector 20 such that the intake-air flow is diverted radially inwardly in relation to the axis of rotation of the compressor wheel 26, such that a relatively small air flow prevails in the region of the return-flow openings 22.1 and 22.2 at the inner circumferential surface of the intake connector. This can also contribute to a reduction in noise.

(15) FIG. 2 shows a compressor 1 which differs from that of FIG. 1 in particular in that, instead of a separation edge 24 for assisting as quiet as possible a merging of the different air flows, it has return-flow openings 122.1 and 122.2 which, over at least a part of their radial extent, are formed so as to be open toward a compressor-wheel-side face side 150 of the intake connector 20, that is to say with corresponding openings 123.1 and 123.2 toward the face side 150.

(16) FIG. 3 schematically shows a cross section through the intake connector 20. The lines P1 to P7 represent different isobars in the pressure profile of the air intake flow in the interior 12 of the intake pipe 8 at the level of the return-flow openings 22.1 and 22.2. Two adjacent isobar lines P, for example P1 and P2, indicate in each case a region of similar or substantially equal pressure in the intake pipe 8.

(17) In the embodiments of the compressor 1 as per FIG. 1 or FIG. 2, the return-flow openings 22.1 and 22.2 are arranged in such a region of similar or substantially equal pressure. In this way, crosstalk between the two openings 22.1 and 22.2, in the case of which air would flow into the ring-shaped groove 16 at one opening 22.1 or 22.2 and out again at the other opening 22.2 or 22.1 with relatively low pressure potential, can be prevented, along with associated pressure losses upstream of the compressor wheel.

(18) By means of a corresponding configuration of the intake geometry, it is self-evidently also possible, in an exemplary embodiment which is not illustrated, for an intake connector with more than two return-flow openings to be installed, if all return-flow openings have substantially the same pressure potential.

(19) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.