Supply of a mixture of air and exhaust gas to the compressor wheel of the compressor

Abstract

In the technical field of compressors, a system (100) is provided that is configured to supply a compressor wheel of a compressor (10) with a mixture of air and exhaust gas. The system (100) comprises a main flow passage (30) configured to receive a supply of air in its first part (31) and to exit into a region (14) in which the compressor wheel is located at its outlet end (33) in order to receive a supply of exhaust gas further downstream in its second part (32), and an exhaust gas supply device connected to the main flow passage (30) at the position of the second part (32). The exhaust gas supply device is designed as a distributor composed of at least two exhaust gas supply passages (22, 23, 24, 25) that are separated from each other along at least a substantial part of their length.

Description

Technical Field

[0001] First, the present invention relates to a system configured to supply a mixture of air and exhaust gas to a compressor wheel of a compressor. The system includes a main flow path configured to flow out into a region where the compressor wheel is disposed at an outlet end, receive an air supply in its first portion, and receive an exhaust gas supply in its second portion closer to the outlet end than the first portion, and an exhaust gas supply device connected to the main flow path at the position of the second portion.

[0002] Second, the present invention relates to an assembly of a turbocharger and a system as described above.

[0003] Third, the present invention relates to an exhaust gas supply device configured to be used in a system configured to supply a mixture of air and exhaust gas to a compressor wheel of a compressor.

[0004] Fourth, the present invention relates to a method of supplying a mixture of air and exhaust gas to a compressor wheel of a compressor. The method includes providing an air flow and directing the air flow toward a region where the compressor wheel is disposed, and providing exhaust gas and injecting the exhaust gas into the air flow at an injection position on the air flow.

[0005] Fifth, the present invention relates to a method of manufacturing a system configured to supply a mixture of air and exhaust gas to a compressor wheel of a compressor. The method includes providing a main flow path and disposing the main flow path to flow out into a region where the compressor wheel is disposed at an outlet end, and providing an exhaust gas supply device and connecting the exhaust gas supply device to the main flow path.

Background Art

[0006] The field where a compressor is commonly applied is the field of turbochargers. A turbocharger is used for the purpose of supplying air at a pressure (boost pressure) higher than atmospheric pressure to the intake port of an internal combustion engine. Generally, a turbocharger includes a turbine wheel arranged and configured to be driven by the exhaust gas flow of the engine. The turbine wheel is attached to a rotatable shaft and housed in a turbine housing. The compressor wheel is attached to the other end of the shaft and housed in a compressor housing. Therefore, the compressor wheel is arranged to rotate together with the turbine wheel. The compressor wheel serves to supply compressed air to the intake manifold of the engine.

[0007] During the operation of the turbocharger, the exhaust gas flow of the engine is introduced into the turbine housing through the inlet of the turbine housing and flows towards the turbine wheel through at least one scroll-shaped volute. The turbine wheel is configured to rotate under the influence of the exhaust gas flow, thereby causing the shaft and the compressor wheel to also rotate. In this way, the compressor wheel can realize the intended function of the turbocharger, that is, the function of compressing the air supplied to the engine. Generally, there are other ways to drive the compressor wheel of a compressor, such as driving the compressor wheel by an electric motor and driving the compressor wheel by connecting it to an internal combustion engine.

[0008] In the technical field of turbochargers, low-pressure exhaust gas recirculation, generally abbreviated as LP-EGR, is known. This is an exhaust gas recirculation configuration in which exhaust gas is taken in downstream of the turbine of the turbocharger and introduced into the air flow towards the compressor upstream of the compressor of the turbocharger in a region known as the mixing region. The exhaust gas and air mixing design from widely applied LP-EGR systems includes a T-joint. According to the insight of the present invention, in this design, a non-uniform flow field is obtained by the T-joint configuration, which causes a decrease in the performance of the compressor. In particular, the mixing affects the compressor pressure ratio, the compressor efficiency, and the condensation of water. Regarding the condensation of water, it should be noted that this can be disadvantageous because water droplets on the blades may cause erosion of the blades of the compressor wheel due to the influence of the water droplets.

Summary of the Invention

Problems to be Solved by the Invention

[0009] An object of the present invention is to reduce the above-described problematic effects of the conventional T-joint configuration. Generally speaking, an object of the present invention is to reduce the influence of the mixing of exhaust gas and fresh air supplied to the compressor wheel on the performance of the compressor while keeping the influence of condensation at an acceptable low level.

[0010] Aspects of the present invention are described in the appended independent and dependent claims. The features of the dependent claims are not only explicitly described in the claims but also can be combined with the features of the respective independent claims as necessary and are explained in the following description.

Means for Solving the Problems

[0011] In view of the above, the present invention provides a system configured to supply a mixture of air and exhaust gas to a compressor wheel of a compressor, the system comprising: a main flow path that flows out into a region where the compressor wheel is disposed at an outlet end and is configured to receive a supply of air in a first portion and a supply of exhaust gas in a second portion closer to the outlet end than the first portion; and an exhaust gas supply device connected to the main flow path at the position of the second portion, the exhaust gas supply device being designed as a distributor including at least two exhaust gas supply paths separated from each other along at least a substantial portion of their lengths.

[0012] From the above general definition of the system according to the present invention, it follows that the present invention provides a configuration of a system that enables injecting exhaust gas into an air flow in a plurality of separate circumferentially distributed ways. In the context of the present invention, this can be achieved without applying complex structural means such as arranging a ported shroud or a vortex generation chamber around the main flow path at the injection position, by means of a specific configuration with exhaust gas supply paths separated from each other along at least a substantial portion of their lengths. By splitting a single individual exhaust gas supply line into a plurality of exhaust gas supply lines, the reduction in the performance of the compressor is reduced compared to the conventional situation. It is advantageous for the dispersion effect of the means according to the present invention if the exhaust gas supply paths extend towards different peripheral positions on the main flow path.

[0013] In a practical embodiment, the exhaust gas supply device includes a central inlet flow path configured to receive the supply of exhaust gas at a position upstream of the exhaust gas supply path, and the exhaust gas supply path is arranged to extend from the central inlet flow path. Further, in the context of the present invention, it is practical for the exhaust gas supply device to be connected to the main flow path at the end of the exhaust gas supply path. In such a case, each of the exhaust gas supply paths directly flows out into the main flow path, so that during the operation of the system, the exhaust gas flow in the air flowing through the main flow path towards its outlet end can be directly injected without first mixing with the exhaust gas flows of other exhaust gas supply paths. Such a configuration can be easily realized based on the application of exhaust gas supply paths that are separated from each other along at least a substantial part of their lengths, and it may be practical for the exhaust gas supply paths to be separated from each other along their entire lengths.

[0014] In the context of the present invention, possible further means for reducing the influence of the injection of exhaust gas in the air on the performance of the compressor while keeping the influence of condensation at an acceptable low level include a configuration in which each of the exhaust gas supply paths is connected to the main flow path axially inclined and / or without circumferential inclination. Thereby, each exhaust gas flow is introduced into the air flow as smoothly as possible, and further downstream flow uniformity is promoted.

[0015] The present invention covers the option of an exhaust gas supply path connected to the main flow path at a single axial position on the main flow path. This may be advantageous from both the perspective of reducing the flow disturbance in the main flow path and the perspective of the manufacturability of the system.

[0016] In an advantageous embodiment of the system according to the present invention, each of the exhaust gas supply paths includes a portion whose cross-sectional area decreases in the flow direction. Based on this design of the exhaust gas supply path, acceleration of the exhaust gas flow can be achieved, thereby further supporting the injection of the exhaust gas flow into the air flow. Regarding the position of the portion where the cross-sectional area decreases in the flow direction, various options are applicable, such as setting it at the position of the end on the main flow path side of the exhaust gas supply path.

[0017] Regarding the use of the term "flow path" in the context of this specification, it should be noted that there is no implicit link to a specific cross-sectional shape of the flow path defined by the flow path. The cross-sectional shape does not necessarily have to be circular, but this can be an option. The indication that the exhaust gas supply paths are separated from each other along at least a substantial part of their length should be understood to mean that the flow through the flow paths is separated from each other along at least a substantial part of the length of the flow paths, which can actually mean that there is space between the flow paths or that the flow paths are arranged side by side and extend.

[0018] Regarding the cross-sectional shape of the exhaust gas supply path, it should be noted that it may be practical when the exhaust gas supply path has a flat cross-sectional shape along at least a part of its length, preferably at least at the end on the main flow path side. This may be a way to prevent the exhaust gas from entering deep into the air flow and staying around the main flow path. As a result, the disturbance of the air flow is reduced, and the pressure loss and velocity loss in the zone where the air and the exhaust gas are mixed are decreased. Without this, the air and the exhaust gas would mix more strongly. Furthermore, by making the zone where the air and the exhaust gas are mixed flat, condensation is reduced compared to a shape where the exhaust gas is injected deep into the air flow and the mixing is strong.

[0019] In a feasible embodiment of the system according to the present invention, the cross-sectional area of the main flow path decreases in the flow direction in the region of the main flow path where the exhaust gas supply device is connected to the main flow path. Alternatively, the cross-sectional area of the main flow path decreases in the flow direction in the region of the main flow path upstream of the position where the exhaust gas supply device is connected to the main flow path. In the first case, the system is configured to be able to simultaneously perform the injection of the exhaust gas into the air flow and the contraction of the mixture of the exhaust gas and the air thus obtained. In the second case, the system is configured to first achieve the contraction of the air and then the injection of the exhaust gas into the air flow. The cross-sectional area of the main flow path may also decrease in the flow direction in the region of the main flow path downstream of the position where the exhaust gas supply device is connected to the main flow path.

[0020] Comparing the prior art with the options covered by the present invention, it can be seen that, probably in combination with the incorporation of flow contraction, by splitting from a single separate injection position into a plurality of separate injection positions circumferentially located, the influence of the wake flow is reduced. As a result, the pressure ratio decreases and the efficiency loss of the compressor is reduced. However, this may be because the overall mixing surface area increases. Bringing the injection position closer to the compressor wheel shortens the mixing distance, reduces the risk of condensation, and thereby reduces the risk of causing serious damage to the compressor wheel.

[0021] From a manufacturing perspective, it may be advantageous if the main flow path is formed by joining at least two separate components. For example, one of the components may have an inlet opening at a position where the exhaust gas supply device is connected, and another of the components may include a fluid contraction portion, i.e., a portion where the cross-sectional area of the main flow path decreases as seen in the flow direction.

[0022] In the field of turbochargers, it is known that a bypass valve passage for recirculating air to the compressor can be provided, but the cross-sectional shape of the passage defined by the bypass valve passage does not necessarily have to be circular. In this regard, it may be advantageous if the exhaust gas supply device comprises at least one coupling region configured to couple such a bypass valve passage to the exhaust gas supply device, and it should be noted that the at least one coupling region can be arranged at any suitable location of the exhaust gas supply device, for example, in one of the exhaust gas supply passages. In this configuration, when the bypass valve in the bypass valve passage is opened, air is added to the exhaust gas flowing through the exhaust gas supply device. Performance improvement of the compressor can be expected by operating the bypass valve. In fact, this tendency may be even more pronounced when the bypass valve passage is connected to the exhaust gas supply device, since no additional openings are required in the main flow region. It should be noted that in practice, there is not always a flow through the bypass valve passage, and the same applies to the supply flow of exhaust gas to the exhaust gas supply device. Considering this, four different combinations are possible. That is, the exhaust gas supply device receives a) both the incoming exhaust gas flow and the flow from the bypass valve passage, b) does not receive a flow, c) only the incoming exhaust gas flow, or d) only the flow from the bypass valve passage.

[0023] It may be useful for at least a part of the exhaust gas supply device of the system to be integrated into a component configured to be used as a cover component of the compressor in order to achieve a compact structure that saves space and / or to have only a minimum number of separate parts.

[0024] The invention also relates to an assembly of a turbocharger and the system defined and described above.

[0025] Furthermore, the present invention also relates to an exhaust gas supply device. Referring to the above description of the basic aspects of the present invention, such an exhaust gas supply device is configured for use in a system configured to supply a mixture of air and exhaust gas to a compressor wheel of a compressor. The exhaust gas supply device is designed as a distributor including at least two exhaust gas supply paths separated from each other along at least a substantial portion of its length. It should be noted that the exhaust gas supply device comprises a single integrated component including at least two exhaust gas supply paths. As described above, it is practical when the exhaust gas supply device has a central inlet flow path and the exhaust gas supply paths are arranged to extend from the central inlet flow path. The other aspects of the present invention described above are equally applicable to the exhaust gas supply device itself.

[0026] Regarding the method, the present invention relates to a method of supplying a mixture of air and exhaust gas to a compressor wheel of a compressor. The method includes providing an air flow and directing the air flow towards the region where the compressor wheel is disposed, and providing exhaust gas and injecting the exhaust gas into the air flow at an injection position on the air flow. The exhaust gas is provided as at least two separate exhaust gas flows directed towards the injection position on the air flow from different sides of the air flow. As described above, the present invention covers the option that each of the at least two separate exhaust gas flows is directly injected into the air flow without first mixing with other exhaust gas flows. Furthermore, as described above, the present invention covers the option that separate exhaust gas flows are obtained by separating a single supply of exhaust gas flow.

[0027] It will be understood that various further options regarding the method according to the present invention may relate to many of the options described above in relation to the system according to the present invention and may include the same features or combinations of features. Therefore, the aspects of the foregoing discussion and description are also applicable when the present invention is expressed from the perspective of a method.

[0028] The present invention further relates to a method of manufacturing a system configured to supply a mixture of air and exhaust gas to a compressor wheel of a compressor, the method comprising: providing a main flow path and arranging the main flow path to flow out into a region where the compressor wheel is disposed at an outlet end; providing an exhaust gas supply device designed as a distributor including at least two separate exhaust gas supply paths separated from each other along a substantial portion of the length, and connecting the exhaust gas supply device to the main flow path. Among the many options that exist under the general concept of the manufacturing method, the following are mentioned: a) the step of connecting the exhaust gas supply device to the main flow path and performed at the end of the exhaust gas supply path, b) the step in which at least two exhaust gas supply paths are connected to the main flow path at different peripheral positions on the main flow path, and c) the step of providing the main flow path includes providing at least two separate components and coupling them to each other.

[0029] Further features and advantages of the present invention will become apparent from the description of the present invention by way of exemplary and non-limiting embodiments of a system configured to supply a mixture of air and exhaust gas to a compressor wheel of a compressor and components of such a system.

[0030] Those skilled in the art will understand that the described embodiments of the system according to the present invention are essentially merely illustrative and should not be construed as limiting the scope of protection defined in the claims in any way. Those skilled in the art will understand that alternative and equivalent embodiments of the system can be conceived and implemented without departing from the scope of protection of the present invention.

[0031] Please refer to the figures on the attached drawing sheet. Since the figures are essentially schematic, they are not necessarily drawn to scale. Note that the same reference numerals indicate the same or similar parts.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0033] These figures relate to advantageous practical embodiments of system 100 according to the present invention, which system 100 is configured to supply a mixture of air and exhaust gas to the compressor wheel 11 of compressor 10 and will hereinafter be referred to as an air / gas supply system. Compressor 10 may be, for example, part of a turbocharger. The settings of these practical embodiments are aimed at injecting exhaust gas into the air flow in a plurality of discrete and circumferentially dispersed ways in order to obtain the beneficial effects of a) a reduction in the mixing of exhaust gas and air and b) an improvement in the uniformity of the flow towards compressor wheel 11, whereby the performance of the compressor is considerably improved compared to the prior art. Further aspects of the practical embodiments are also selected to contribute to the beneficial effects described above and / or other beneficial effects described hereinafter.

[0034] Here, the specific settings of the practical embodiments as described above are realized by using an exhaust gas supply device 20 designed as a distributor. A practical embodiment of such an exhaust gas supply device 20 is shown in FIG. 1. In this embodiment, the exhaust gas supply device 20 comprises a central inlet flow path 21 and four exhaust gas supply paths 22, 23, 24, 25 arranged to extend from the central inlet flow path 21 like separate branches. The central inlet flow path 21 is configured to receive the supply of exhaust gas at a position upstream of the exhaust gas supply paths 22, 23, 24, 25. Having four exhaust gas supply paths 22, 23, 24, 25 in the exhaust gas supply device 20 is practical, but it does not change the fact that the number of exhaust gas supply paths 22, 23, 24, 25 can be selected differently. According to a practical option, it receives the supply of exhaust gas from an internal combustion engine. The outlet pipe 12 of compressor 10 is shown in FIGS. 2 and 3.

[0035] In the air / gas supply system 100, the exhaust gas supply device 20 is connected to the main flow path 30 as shown in FIGS. 2 and 3, and the ends of the main flow path 30 and the exhaust gas supply paths 22, 23, 24, 25 are shown. The main flow path 30 is configured such that the compressor wheel 11 flows into the region 14 where it is disposed at its outlet end 33, receives air supply in its first portion 31, and receives exhaust gas supply from the exhaust gas supply device 20 in its second portion 32. The second portion 32 is closer to the outlet end 33 than the first portion 31. In particular, in FIG. 3, it can be seen how the exhaust gas supply paths 22, 23, 24, 25 are configured as individual paths for a plurality of injection regions arranged circumferentially on the main flow path 30. As shown in FIGS. 5 to 9, an inlet opening 34 is provided in the main flow path 30 precisely at the position where the exhaust gas supply paths 22, 23, 24, 25 are connected to the main flow path 30.

[0036] In the illustrated practical embodiment of the air / gas supply system 100, the exhaust gas supply paths 22, 23, 24, 25 extend toward a position on the main flow path 30 where the inlet opening 34 is present, and that position is a different position in the circumferential direction of the main flow path 30 and is at the same level in the axial direction of the main flow path 30. The exhaust gas supply paths 22, 23, 24, 25 have a flat cross-sectional shape, and the inlet opening 34 of the main flow path 30 is shaped like an elongated slot, but this does not change the fact that the above-mentioned shapes can be selected differently.

[0037] Furthermore, in the illustrated practical embodiment of the air / gas supply system 100, as described, the exhaust gas supply device 20 is connected to the main flow path 30 at the ends of the exhaust gas supply paths 22, 23, 24, 25, and each of the exhaust gas supply paths 22, 23, 24, 25 flows directly into the main flow path 30, whereby during operation of the air / gas supply system 100, the exhaust gas flow can be directly injected into the air flowing through the main flow path 30 toward its outlet end 33 without first mixing with the exhaust gas flow of any of the other exhaust gas supply paths 22, 23, 24, 25.

[0038] A part of the air / gas supply system 100 can be incorporated into the cover component 13 of the compressor 10, and as a result, a compact configuration with a minimum number of separate components can be obtained. In this regard, FIG. 4 in particular is helpful in showing how such a cover component 13, the main flow path 30, and the exhaust gas supply device 20 can be provided as an assembly.

[0039] The main flow path 30 may be provided with a fluid contraction portion 35 which is a portion where the cross-sectional area of the main flow path 30 decreases when viewed in the flow direction F. At the position of the fluid contraction portion 35, an acceleration of the fluid flow can be obtained. The present invention covers various possible selections regarding the positions at which the exhaust gas supply paths 22, 23, 24, 25 are connected to the main flow path 30 with respect to the position of an optional fluid contraction portion 35 of the main flow path 30. FIGS. 5 and 6, and further FIG. 9, show options for the positions at which the exhaust gas supply paths 22, 23, 24, 25 are connected to the main flow path 30 immediately downstream of the fluid contraction portion 35. Also, it is conceivable that the cross-sectional area of the main flow path 30 decreases at the positions where the exhaust gas supply paths 22, 23, 24, 25 are connected to the main flow path 30. This option is shown in FIGS. 7 and 8. Another realizable option is the option that the positions at which the exhaust gas supply paths 22, 23, 24, 25 are connected to the main flow path 30 are upstream of the fluid contraction portion 35.

[0040] The exhaust gas supply paths 22, 23, 24, 25 may include a portion 26 whose cross-sectional area decreases in the flow direction, as shown in FIG. 9. The portion 26 may be at any position on the exhaust gas supply paths 22, 23, 24, 25. In the example shown in FIG. 9, the position is at the connection portion to the main flow path 30. In any case, an acceleration of the exhaust gas flow is obtained at the position of the portion 26 whose cross-sectional area decreases in the flow direction.

[0041] Selecting the position of the fluid contraction portion 35 of the main flow path 30 and / or the portion 26 whose cross-sectional area decreases in the exhaust gas supply paths 22, 23, 24, 25 is a method of adjusting the static pressure (and velocity) of the exhaust gas flow at the inlet opening 34 of the main flow path 30.

[0042] From the above, in the configuration shown in FIG. 8, the contraction / acceleration of the fluid and the exhaust gas injection occur simultaneously in the main flow path 30, while in the configuration shown in FIG. 9, the contraction / acceleration of the fluid occurs prior to the exhaust gas injection in the main flow path 30. Particularly in the latter case, high stability against the bulk flow turbulence (inlet bend) is expected. In any case, it may be advantageous for the position of the exhaust gas injection to be close to the region 14 where the compressor wheel 11 is disposed. Even when the total amount of condensed water in the mixture of air and exhaust gas becomes larger, if the position of the exhaust gas injection is close to the region 14 where the compressor wheel 11 is disposed, the expected influence of the condensation on the compressor wheel 11 may still be acceptable.

[0043] As can be best seen from FIG. 3, each of the exhaust gas supply paths 22, 23, 24, 25 is connected to the main flow path 30 without being inclined in the circumferential direction. Further, as can be best seen in FIGS. 8 and 9, each of the exhaust gas supply paths 22, 23, 24, 25 is connected to the main flow path 30 with an axial inclination α.

[0044] FIG. 10 shows an alternative embodiment of the exhaust gas supply device 20. This embodiment is different from the embodiment shown in FIG. 1 in terms of the configuration of the ends of the exhaust gas supply paths 22, 23, 24, 25. In the alternative embodiment, the ends of the exhaust gas supply paths 22, 23, 24, 25 are interconnected. Thus, in the alternative embodiment, the exhaust gas supply paths 22, 23, 24, 25 are separated from each other along a substantial part of their length, rather than along their entire length. The exhaust gas injection realized by the exhaust gas supply device 20 according to the alternative embodiment is not a plurality of discrete ones, but the exhaust gas supply device 20 does not incorporate a conventional single or multiple scrolls either. In the illustrated example, the interconnection of the exhaust gas supply paths 22, 23, 24, 25 is on the side of the main flow path 30. Generally, it is considered practical if there is an interconnection downstream of a position where the circumferential angle β of the exhaust gas flow remains between -45° and +45°.

[0045] The scope of the present invention is not limited to the foregoing examples, and it will be apparent to those skilled in the art that some changes and modifications can be made without departing from the scope of the invention defined by the appended claims. In particular, combinations of specific features of various aspects of the present invention are possible. One aspect of the present invention can be further advantageously enhanced by adding features described in connection with another aspect of the present invention. Although the present invention has been illustrated and described in detail in the drawings and the description, such drawings and description are to be considered illustrative or exemplary only and not limiting.

[0046] The present invention is not limited to the disclosed embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, by considering the drawings, the description, and the appended claims. In the claims, the word "comprising" does not exclude other steps or elements, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope of the invention.

[0047] The notable aspects of the present invention are summarized as follows. In the technical field of compressors, a system 100 is provided that is configured to supply a mixture of air and exhaust gas to a compressor wheel 11 of a compressor 10. The system 100 includes a main flow path 30 configured to flow out into a region 14 where the compressor wheel 11 is disposed at an outlet end 33, receive an air supply at a first portion 31, and receive an exhaust gas supply at a second portion 32 closer to the outlet end 33 than the first portion 31, and an exhaust gas supply device 20 connected to the main flow path 30 at the position of the second portion 32. The exhaust gas supply device 20 is designed as a distributor having at least two exhaust gas supply paths 22, 23, 24, 25 separated from each other along at least a substantial portion of their lengths.

Explanation of Reference Signs

[0048] 100 Air / Gas Supply System 10 Compressor 11 Compressor Wheel 12 Outlet Pipe of Compressor 13 Cover Component of Compressor 14 Region where Compressor Wheel is Arranged 20 Exhaust Gas Supply Device 21 Central (Exhaust Gas) Inlet Flow Path 22 Exhaust Gas Supply Path 23 Exhaust Gas Supply Path 24 Exhaust Gas Supply Path 25 Exhaust Gas Supply Path 26 Portion with Decreasing Cross - sectional Area 30 Main Flow Path 31 First Portion of Main Flow Path 32 Second Portion of Main Flow Path 33 Outlet End of Main Flow Path 34 Inlet Opening of Main Flow Path 35 Fluid Contraction Portion α Axial Inclination of Exhaust Gas Supply Path β Circumferential Angle of Exhaust Gas Flow

Claims

1. A system (100) configured to supply a mixture of air and exhaust gas to a compressor wheel (11) of a compressor (10), flowing out into a region (14) where the compressor wheel (11) is disposed at an outlet end (33), receiving air supply at a first portion (31), and receiving exhaust gas supply at a second portion (32) closer to the outlet end (33) than the first portion (31), a main flow path (30); and an exhaust gas supply device (20) connected to the main flow path (30) at a position of the second portion (32). The exhaust gas supply device (20) is designed as a distributor including at least two exhaust gas supply paths (22, 23, 24, 25) separated from each other along at least a substantial part of their lengths, the exhaust gas supply device (20) is connected to the main flow path (30) at ends of the exhaust gas supply paths (22, 23, 24, 25), and each of the exhaust gas supply paths (22, 23, 24, 25) directly discharges into the main flow path (30), whereby, during operation of the system (100), an exhaust gas flow can be directly injected into air flowing through the main flow path (30) towards the outlet end (33) without first mixing with exhaust gas flows of other exhaust gas supply paths (22, 23, 24, 25). A system (100).

2. The system (100) according to claim 1, wherein each of the exhaust gas supply paths (22, 23, 24, 25) extends towards different peripheral positions of the main flow path (30).

3. The exhaust gas supply device (20) includes a central inlet flow path (21) configured to receive exhaust gas supply at upstream positions of each of the exhaust gas supply paths (22, 23, 24, 25), and the exhaust gas supply paths (22, 23, 24, 25) are arranged to extend from the central inlet flow path (21). The system (100) according to claim 1 or 2.

4. The system (100) according to any one of claims 1 to 3, wherein each of the exhaust gas supply paths (22, 23, 24, 25) is connected to the main flow path (30) while being inclined axially (α) and / or not inclined circumferentially (β).

5. The system (100) according to any one of claims 1 to 4, wherein each of the exhaust gas supply paths (22, 23, 24, 25) is connected to the main flow path (30) at a single axial position of the main flow path (30).

6. The system (100) according to any one of claims 1 to 5, wherein each of the exhaust gas supply paths (22, 23, 24, 25) includes a portion (26) whose cross-sectional area decreases in the flow direction (F).

7. The system (100) according to any one of claims 1 to 4, wherein each of the exhaust gas supply paths (22, 23, 24, 25) includes a portion (26) whose cross-sectional area decreases in the flow direction (F) and which is located at the position of the end of the exhaust gas supply path (22, 23, 24, 25) on the main flow path (30) side.

8. The system (100) according to any one of claims 1 to 5, wherein each of the exhaust gas supply paths (22, 23, 24, 25) has a flat cross-sectional shape along at least a part of its length.

9. The system (100) according to any one of claims 1 to 7, wherein the cross-sectional area of the main flow path (30) decreases in the flow direction (F) in the region of the main flow path (30) where the exhaust gas supply device (20) is connected to the main flow path (30).

10. The system (100) according to any one of claims 1 to 8, wherein the cross-sectional area of the main flow path (30) decreases in the flow direction (F) in the region of the main flow path (30) either upstream or downstream of the position where the exhaust gas supply device (20) is connected to the main flow path (30).

11. The system (100) according to any one of claims 1 to 10, wherein the main flow path (30) is composed of at least two separate components joined together.

12. The system (100) according to any one of claims 1 to 11, wherein the exhaust gas supply device (20) includes at least one coupling region configured to enable coupling of a bypass valve flow path of the compressor (10) to the exhaust gas supply device (20).

13. An assembly of a turbocharger and the system (100) according to any one of claims 1 to 12.

14. An exhaust gas supply device (20) configured to be used in a system (100) configured to supply a mixture of air and exhaust gas from an outlet end (33) of a main flow path (30) to a compressor wheel (11) of a compressor (10), wherein the exhaust gas supply device (20) is designed as a distributor including at least two exhaust gas supply paths (22, 23, 24, 25) separated from each other along at least a substantial part of the length, the exhaust gas supply device (20) comprises a single integral part including the at least two exhaust gas supply paths (22, 23, 24, 25), the exhaust gas supply device (20) is connected to the main flow path (30) at respective ends of the exhaust gas supply paths (22, 23, 24, 25), and each of the exhaust gas supply paths (22, 23, 24, 25) flows directly into the main flow path (30), whereby an exhaust gas flow can be directly injected into air flowing through the main flow path (30) towards the outlet end (33) without first mixing with exhaust gas flows of other exhaust gas supply paths (22, 23, 24, 25) during operation of the system (100).

15. A central inlet flow path (21), wherein each of the exhaust gas supply paths (22, 23, 24, 25) is arranged to extend from the central inlet flow path (21), the exhaust gas supply device (20) according to claim 14, comprising the central inlet flow path (21).

16. A method of manufacturing a system (100) configured to supply a mixture of air and exhaust gas to a compressor wheel (11) of a compressor (10), providing a main flow path (30) and arranging the main flow path (30) so that the compressor wheel (11) flows out into a region (14) where its outlet end (33) is located; providing an exhaust gas supply device (20) designed as a distributor including at least two separate exhaust gas supply paths (22, 23, 24, 25) separated from each other along a substantial part of the length, and connecting the exhaust gas supply device (20) to the main flow path (30), the step of connecting the exhaust gas supply device (20) to the main flow path (30) is performed at each end of the exhaust gas supply paths (22, 23, 24, 25), each of the exhaust gas supply paths (22, 23, 24, 25) directly flows out into the main flow path (30), whereby during operation of the system (100), the exhaust gas flow can be directly injected into the air flowing through the main flow path (30) towards the outlet end (33) without first mixing with the exhaust gas flows of the other exhaust gas supply paths (22, 23, 24, 25).

17. The manufacturing method according to claim 16, wherein each of the at least two exhaust gas supply paths (22, 23, 24, 25) is connected to the main flow path (30) at different peripheral positions of the main flow path (30).

18. The manufacturing method according to claim 16 or 17, wherein the step of providing the main flow path (30) includes providing and joining at least two separate components.

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