RADIAL COMPRESSOR

Abstract

A radial compressor for an exhaust gas turbocharger may include a compressor housing in which a flow channel is arranged, a compressor wheel arranged in the flow channel, a device influencing a characteristic field, and a discharge channel. The flow channel may delimit a flow path of air through the radial compressor. The flow channel may have a suction section via which the compressor wheel sucks in air. The compressor housing may have a circumferential section circumferentially surrounding the compressor wheel in which a spiral channel of the flow channel may be arranged via which air compressed by the compressor wheel flows out. The device may include a cavity fluidically connected to the suction section. The discharge channel may be arranged in the compressor housing feeding, via an inlet mouth point, into the cavity and extending to an outlet mouth point fluidically connecting the cavity to the spiral channel.

Claims

1. A radial compressor for an exhaust gas turbocharger, comprising: a compressor housing in which a flow channel is arranged, the flow channel delimiting a flow path of air through the radial compressor; a compressor wheel arranged in the flow channel and non-rotatably coupled to a rotatably mounted shaft; the flow channel having a suction section via which the compressor wheel sucks in air during operation; the compressor housing having a circumferential section surrounding the compressor wheel in a circumferential direction, in which a spiral channel of the flow channel extending in the circumferential direction is arranged via which air compressed during operation via the compressor wheel flows out; a device influencing a characteristic field of the radial compressor, the device including a cavity at least one of fluidically connected and fluidically connectable to the suction section; a discharge channel is arranged in the compressor housing feeding, via an inlet mouth point, into the cavity and extending to an outlet mouth point, the discharge channel fluidically connecting the cavity to the spiral channel.

2. The radial compressor according to claim 1, wherein the device further includes an element received in the cavity and configured to variably change a flow cross-section in the flow channel.

3. The radial compressor according to claim 1, wherein the outlet mouth point is disposed spaced apart axially and radially from the inlet mouth point relative to the shaft.

4. The radial compressor according to claim 1, wherein the discharge channel includes a gradient from the inlet mouth point to the outlet mouth point.

5. The radial compressor according to claim 4, wherein the gradient is constant.

6. The radial compressor according to claim 1, wherein the inlet mouth point is arranged at an end of the cavity facing away from the shaft.

7. The radial compressor according to claim 1, wherein the outlet mouth point is arranged on a side of the inlet mouth point opposite the shaft and at an axial distance from the inlet mouth point relative to the shaft.

8. The radial compressor according to claim 1, wherein the outlet mouth point is arranged on the spiral channel (19) so such that the discharge channel extends to the spiral channel.

9. The radial compressor according to claim 1, wherein the flow channel further includes a diffusor arranged between the compressor wheel and the spiral channel, wherein the discharge channel fluidically connects the cavity, via the diffusor, to the spiral channel.

10. The radial compressor according to claim 9, wherein the outlet mouth point is arranged on the diffusor such that the discharge channel extends to the diffusor.

11. The radial compressor according to claim 1, wherein the cavity includes a catchment trough on a side facing radially away from shaft into which the discharge channel feeds via the inlet mouth point.

12. The radial compressor according to claim 11, wherein the catchment trough tapers radially inward in a direction toward the inlet mouth point in a funnel-like manner.

13. The radial compressor according to claim 11, wherein the catchment trough extends in the circumferential direction.

14. The radial compressor according to claim 1, wherein the discharge channel is structured as a bore in the compressor housing.

15. An exhaust gas turbocharger comprising a turbine including a turbine wheel driven by exhaust gas during operation, and a radial compressor, the radial compressor including: a compressor housing in which a flow channel is arranged, the flow channel delimiting a flow path of air through the radial compressor; a compressor wheel arranged in the flow channel and non-rotatably coupled to a rotatably mounted shaft; the flow channel having a suction section via which the compressor wheel sucks in air during operation; the compressor housing having a circumferential section surrounding the compressor wheel in a circumferential direction, in which a spiral channel of the flow channel extending in the circumferential direction is arranged via which air compressed during operation via the compressor wheel flows out; a device influencing a characteristic field of the radial compressor, the device including a cavity at least one of fluidically connected and fluidically connectable to the suction section; and a discharge channel arranged in the compressor housing feeding, via an inlet mouth point, into the cavity and extending to an outlet mouth point, the discharge channel fluidically connecting the cavity to the spiral channel; wherein the shaft is drivingly connected to the turbine wheel.

16. The radial compressor according to claim 1, wherein: at least a portion of the suction section extends axially relative to the shaft; and the cavity circumferentially surrounds the suction section relative to the shaft.

17. The radial compressor according to claim 1, wherein the suction section is arranged upstream of the compressor wheel and axially adjoins the compressor wheel.

18. The radial compressor according to claim 1, wherein the device further includes an element adjustably arranged within the cavity, and wherein an adjustment of the element alters a flow cross-section of the suction section.

19. The radial compressor according to claim 7, wherein the discharge channel defines a gradient from the cavity to the outlet mouth point such that an accumulation of at least one of a liquid and a plurality of foreign particles within the cavity is dischargeable therefrom via the discharge channel when there is not a pressure difference between the suction area and the spiral channel.

20. A radial compressor for an exhaust gas turbocharger, comprising: a compressor housing in which a flow channel is arranged, the flow channel delimiting a flow path through which air is flowable; a compressor wheel arranged in the flow channel and non-rotatably coupled to a rotatably mounted shaft; the flow channel having a suction section through which air is drawable via the compressor wheel, at least portions of the suction section extending axially relative to the shaft; the compressor housing having a circumferential section circumferentially surrounding the compressor wheel; the flow channel including a spiral channel disposed within the circumferential section and extending in a circumferential direction therein through which air compressed via the compressor wheel is flowable; the flow channel including a diffusor extending substantially radially to the shaft and fluidically connecting the compressor wheel and the spiral channel; a device configured to influence a characteristic field, the device including a cavity circumferentially surrounding and fluidically connected to the suction section; and a discharge channel arranged in the compressor housing extending from an inlet mouth point in the cavity to an outlet mouth point, the discharge channel fluidically connecting the cavity and the spiral channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Preferred exemplary embodiments of the invention are depicted in the drawings and will be explained in detail in the description hereunder, wherein identical reference symbols refer to identical or similar or functionally identical components, and wherein schematically

[0036] FIG. 1 shows a strongly simplified, circuit-like depiction of a combustion engine system with an exhaust gas turbocharger,

[0037] FIG. 2 shows a cross-section through a part of the radial compressor of the exhaust gas turbocharger,

[0038] FIG. 3 shows a cross-section through a part of the radial compressor in another exemplary embodiment,

[0039] FIG. 4 shows a cross-section through a part of the radial compressor in a further exemplary embodiment.

DETAILED DESCRIPTION

[0040] An exhaust gas turbocharger 1 such as depicted in FIG. 1, comprises a turbine 2 with a turbine wheel 3, which is driven by exhaust gas when in operation. In the exemplary embodiment shown the turbine wheel 3 is drivingly connected via a shaft 4 to a compressor wheel 5 of a radial compressor 6. The compressor wheel 5 axially sucks in air, also called suction air in the following, and compresses the same in radial direction. In the example shown the exhaust gas turbocharger 1 is part of a combustion engine system 7, which apart from the exhaust gas turbocharger 1 also comprises a combustion engine 8. The exhaust gas for driving the turbine wheel 3 originates in the combustion engine 8 and is fed to the turbine wheel 3 via an exhaust gas system 9 of the combustion engine system 7. The radial compressor 6/the compressor wheel 5 are, by comparison, installed in a fresh air plant 10 of the combustion engine system 7, the fresh air plant 10 serving to supply air to the combustion engine. Part of the exhaust air being generated in the combustion engine 8 can be fed via an exhaust gas recirculation line 11 to the fresh air plant 10, in particular upstream of the radial compressor 6. In the example shown, the exhaust gas is taken off the exhaust gas system 9 upstream of the turbine 2, but this can also be done downstream of the turbine 2.

[0041] FIG. 2 shows a section through the radial compressor 6 along the shaft 4, wherein merely one half of the radial compressor 6 is shown, which is the lower half in installed position. The shaft extends along an axial direction 12, i.e. parallel to the axis of rotation of shaft 4, and is rotatably arranged, in particular mounted, in a compressor housing 13 of the radial compressor 6. A flow channel 26 delimiting a flow path 18 of the air in the radial compressor 6 is formed inside the compressor housing 13. The flow channel 26 comprises a suction section 14, via which the compressor wheel 5, in operation, sucks in air axially and which in the example shown, extends in axial direction. Due to the rotation of the compressor wheel 5 the air is accelerated in radial direction and reaches via a diffusor 15 extending transversely to the axial direction 12, i.e. radially, a spiral channel 16 extending in circumferential direction, which are both constituents of the flow channel 26 and through which the flow channel 18 leads. The compressed air can be passed through the spiral channel 16 and fed in particular to the combustion engine 8. The spiral channel 16 and the diffusor 15 are formed in a circumferential section 17 of the compressor housing 13. In the suction section 14 a cavity 19 of a device 20 is formed. The device 20 serves the purpose of influencing the characteristic field of the radial compressor 6, in particular stabilising and/or changing it. With the example shown in FIG. 1, changing the characteristic field is effected with the aid of the device 20. To this end the device 20, in the example shown, comprises a hinted at, adjustable element 21, which is received in the cavity 19 and which, by means of an adjustment, changes the flow cross-section in the flow channel 26, in particular in the suction section 14, and thus the surface of the compressor wheel 5, which is exposed to the flow. The cavity 19 is fluidically connected to the flow path 18 or connectable in operation by adjusting the element 21. Liquid, in particular condensate generated in operation can collect in the cavity 19. Also foreign particles originating for example from the recycled exhaust gas can get into the cavity 19. In order to discharge this liquid, in particular condensate and/or the foreign particles, from the cavity 19, the radial compressor 6 comprises a discharge channel 22, which fluidically connects the cavity 19 to the spiral channel 16. The discharge channel 22 extends from an inlet mouth point 23 to an outlet mouth point 24. The inlet mouth point 23 is arranged on the cavity 19 such that the discharge channel 22 is directly fluidically connected to the cavity 19 via the inlet mouth point 23. The inlet mouth point 23 is arranged at an end of the cavity 19 facing away from the shaft 4. This end, in the installed position of the radial compressor 6, corresponds to the lower end of the cavity 19 viewed in vertical direction. In the example shown the outlet mouth point 24 is arranged on the diffusor 15, such that the discharge channel 22 extends as far as the diffusor 15 and is thus fluidically connected to the spiral channel 16. Due to the fluidic connection of the discharge channel 22 with the diffusor 15 the cavity 19 is exhausted when the radial compressor 6 is operating, so that liquid in the cavity 19 and/or foreign particles in the receiving chamber 19 are exhausted. The inlet mouth point 23 and the outlet mouth point 24 are radially and axially spaced apart from one another, such that the discharge channel 22 comprises a gradient, in particular a constant gradient. This means that the liquid can flow through the discharge channel 22 even outside the operation of the compressor wheel 5, and the liquid, in particular the condensate, in the cavity 19 and/or the discharge channel 22 can be prevented from freezing or at least freezing of the same can be reduced, when the outside temperatures are dropping. In this case the outlet mouth point 24 is arranged axially remote from the inlet mouth point 23 and the suction section 14, and radially remote from the compressor wheel 5/the shaft 4. Moreover the outlet mouth point 24 is arranged on the side of the inlet mouth point 23, which faces away from the compressor wheel 5/the shaft 4.

[0042] In FIG. 3 another exemplary embodiment of the radial compressor 6 is shown. This embodiment is different from the one shown in FIG. 2 in that the device 20 does not comprise such an element 21 received in the cavity 19. In this example the cavity 19 is fluidically connected to a suction section 14, for example in the area of a crescent-shaped indentation 29, and to a contour section 28 of the flow channel 26 following the shape of the compressor wheel 5, wherein the fluidic connection in the area of the indentation 29 in FIG. 3 is not visible because of the perspective. Thus the cavity 19 also establishes a fluidic connection between the suction section 14 and the contour section 28 and thus stabilises the characteristic field of the radial compressor 6. In difference to the example shown in FIG. 2 the cavity 19 therefore comprises two fluidic connections with the flow channel 26. In this case the inlet mouth point 23 is arranged at an end of the cavity 19 facing the shaft 4, so that liquid in the cavity 19, in particular condensate and/or foreign particles can flow away. Thus the discharge of the liquid and/or the foreign particles out of the cavity 19 is further simplified and/or improved.

[0043] FIG. 4 shows a further exemplary embodiment of the radial compressor 6. This embodiment can be realised alternatively or additionally to the variants depicted in FIGS. 2 and 3. In the example in FIG. 4 a catchment trough 25 extending in circumferential direction is formed on the side of the cavity facing away from the shaft 4. In the example shown the catchment trough 25 also comprises a shape tapering away from the shaft 4 in direction of the inlet mouth point 23 and is thus shaped like a funnel. Accordingly liquid, in particular condensate and/or foreign particles, collect in the cavity 19 in the catchment trough 25, even if the radial compressor 6 assumes an oblique position, which may for example occur when the combustion engine system 7, due to the arrangement in an oblique position relative to the horizontal, occupies an oblique position, in particular when an associated vehicle not shown is driving up a slope or down a slope.

[0044] In the examples shown the discharge channel 22 is formed as a bore 27 in the compressor housing 13.