Secondary fluid supply for the diffuser in the compressor stage

Abstract

This document provides embodiments of compressor stages, particularly compressor stages for turbocharging systems and / or turbocompounds, and methods for operating the compressor stage. The compressor stage includes an impeller and a bladed diffuser disposed downstream of the impeller. The bladed diffuser is fluidly connected to the outlet of the impeller and includes an injection device configured to inject secondary fluid into the bladed diffuser. The injection device includes a displaceable port at least partially disposed between adjacent pairs of blades of the diffuser.

Description

Technical Field

[0001] The embodiments described herein relate to compressor stages, particularly compressor stages for turbocharging systems and / or turbo-compound engines, and methods of operating compressor stages. Background Technology

[0002] Many applications using compressor stages involve injecting or recirculating secondary fluids. For example, modern internal combustion engines often require exhaust gas recirculation (EGR) to comply with current and future environmental regulations.

[0003] Different technologies have been developed for injecting or recirculating secondary fluids. For internal combustion engines, low-pressure EGR and high-pressure EGR are typically used, depending on at what pressure level the EGR gas is reintroduced into the engine's air supply path.

[0004] Low-pressure EGR involves introducing EGR gas at a low-pressure level upstream of the compressor stage impeller, which can lead to serious erosion and corrosion problems, particularly concerning the impeller material.

[0005] High-pressure EGR involves introducing EGR gas downstream of the compressor stage, which typically requires an additional EGR blower to overcome the pressure difference between the secondary fluid from the engine exhaust manifold and the primary fluid from the air receiver.

[0006] One attempt to overcome the problems associated with high-pressure and low-pressure EGR is to provide a link in the area between the exhaust manifold and the impeller outlet and diffuser inlet. The high-momentum primary fluid exiting the compressor impeller draws in the EGR gas and pressurizes it, much like a jet pump.

[0007] Current designs for injecting exhaust gas into diffusers include slits or orifices in the compressor stage that connect to appropriate supply lines or channels to inject secondary fluid into the compressor mainstream. These slits or orifices are located between the impeller outlet and the diffuser inlet, as this is downstream of the impeller—thus avoiding impeller erosion and corrosion problems—and upstream of the diffuser—where the static pressure is low enough to draw in the secondary flow.

[0008] However, this design leads to operational problems because the diffuser limits the mass flow rate that can be pushed through it under given upstream total flow conditions. This means the diffuser is either too small to satisfy both the primary and secondary fluids (if the secondary fluid is open), or too large to satisfy only the primary fluid. Summary of the Invention

[0009] In short, a compressor stage and a method for operating the compressor stage are provided to overcome at least some of the limitations described above. This object is achieved by the compressor stage according to claim 1, particularly for a compressor stage for a turbocharging system and / or a turbo-compound engine, and the method for operating the compressor stage according to claim 15. In particular, the object of the invention is to provide a compressor stage that allows the injection of a secondary fluid and is simultaneously adapted to a combined (primary and secondary) flow rate when the secondary fluid is turned on and off.

[0010] According to an embodiment, a compressor stage is provided, particularly for turbocharging systems and / or turbo-compound engines. The compressor stage includes an impeller and a bladed diffuser disposed downstream of the impeller. The bladed diffuser is fluidly connected to the outlet of the impeller. The bladed diffuser also includes an injection device configured to inject secondary fluid into the bladed diffuser. The injection device includes a displaceable port at least partially disposed between adjacent pairs of blades of the diffuser.

[0011] According to another embodiment, a method is provided for operating a compressor stage of a turbocharger system and / or a turbocompound, particularly a method for compressor stage assemblies according to any embodiment of this disclosure. The method includes determining a desired mass flow rate of a secondary fluid, particularly a desired mass flow rate of exhaust gas, and determining an effective cross-section of a bladed diffuser of the compressor, thereby maintaining the compressor impeller within predetermined operating limits. The method further includes adjusting the cross-section of the bladed diffuser to an effective cross-section, particularly through a displaceable port at least partially disposed between adjacent blade pairs of the diffuser by a displacement injection device.

[0012] Other features and advantages will become apparent to those skilled in the art upon reading the following detailed description and reviewing the accompanying drawings. Attached Figure Description

[0013] The components in the figures are not necessarily to scale, but are used to emphasize the principles of the invention. Furthermore, similar reference numerals denote corresponding components in the figures. In the figures:

[0014] Figure 1A A portion of a compressor stage according to an embodiment of this disclosure is described.

[0015] Figure 1B A portion of a compressor stage according to an embodiment of this disclosure is described.

[0016] Figure 2A A portion of a compressor stage according to an embodiment of this disclosure is described.

[0017] Figure 2B A portion of a compressor stage according to an embodiment of this disclosure is described.

[0018] Figure 3A A portion of a compressor stage according to an embodiment of this disclosure is described.

[0019] Figure 3B A portion of a compressor stage according to an embodiment of this disclosure is described. Detailed Implementation

[0020] In the following detailed description, reference is made to the accompanying drawings, which form part of this invention, and which show specific embodiments of the invention.

[0021] As used herein, the terms “having,” “comprising,” “including,” “comprising,” etc., are open-ended terms that indicate the presence of the stated element or feature but do not exclude other elements or features.

[0022] It should be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the invention. Therefore, the following detailed description should not be considered limiting, and the scope of the invention is defined by the appended claims. The embodiments described herein use specific language and should not be construed as limiting the scope of the appended claims. Each embodiment and each aspect so defined may be combined with any other embodiment or any other aspect unless expressly indicated otherwise.

[0023] According to an embodiment, a compressor stage 100 is provided, particularly for turbocharging systems and / or turbo-compound engines.

[0024] The compressor stage 100 includes an impeller 110 having an inlet section and an outlet section or an outlet, and a diffuser 120 having a diffuser inlet section 111. The diffuser 120 is located downstream of the impeller 110. The diffuser inlet section 111 is in fluid communication with the outlet section of the impeller. The compressor stage 100 is configured to draw in a primary fluid, typically air, at the impeller inlet section and to compress and deliver the primary fluid through the compressor stage 100. This path through the compressor stage 100 may also be referred to as a flow channel. The compressor stage 100 may be a centrifugal compressor stage.

[0025] The diffuser 120 is a bladed diffuser comprising a plurality of blades 121, 122, and 123. The bladed diffuser 120 has a housing, wherein the blades 121, 122, and 123 are typically fixed to or integrally formed with the housing. The housing may include sidewalls, particularly a shield side and / or a hub side. The blades 121, 122, and 123 extend between two opposite sidewalls of the housing.

[0026] Figure 1A A portion of a compressor stage 100 according to an embodiment of this disclosure is shown. Large, unfilled arrows indicate primary fluid from impeller 110 (in...). Figure 1A (Only the position of the impeller is shown in the image) The flow is fed to the diffuser inlet section 111 and further fed into the blade diffuser 120. Figure 1A The compressor stage 100 shown includes two blades 121, 122; however, a number of additional blades are typically provided within the bladed diffuser 120.

[0027] Each pair of blades 121, 122, 123 defines a throat section 150. The throat section 150 should be understood as a constricting section that limits the mass flow rate of the fluid delivered through the compressor stage 100. The bladed diffuser 120 typically includes multiple throat sections 150, each throat section 150 being defined by its respective adjacent pair of blades 121, 122, 123.

[0028] According to an embodiment, the throat section 150 includes an upstream portion 151 adjacent to the diffuser inlet 111. At some operating points, the upstream portion 151 may also be referred to as a cross-sectional reduction portion because the cross-sectional area of ​​the flow tube of the fluid delivered through the blade diffuser 120 gradually decreases within the upstream portion 151 of the throat section 150. The throat section 150 also includes a throat position 152. The throat position 152 is the location adjacent to the corresponding blade pair with the smallest geometric cross-sectional area, and typically includes the smallest cross-sectional area of ​​the entire blade diffuser 120 (except for other throat positions 152 defined by other adjacent blade pairs). The throat section 150 includes a downstream portion 153 located downstream of the throat position 152. At some operating points, the downstream portion may also be referred to as a cross-sectional expansion portion because the cross-sectional area of ​​the flow tube of the fluid delivered through the blade diffuser 120 continuously increases downstream of the throat position 152. Therefore, the throat section 150 should be understood as a section generally defined by and located within adjacent blade pairs; however, the throat section 150 is not limited to a single location. The mass flow rate of the fluid conveyed through the bladed diffuser is particularly affected or limited by the throat location 152. For example, Figure 1B and 3B The diagram illustrates the throat segment 150, the upstream portion 151, the throat position 152, and the downstream portion 153.

[0029] The blade diffuser 120 also includes an injection device 130. The injection device is configured to inject a secondary fluid into the blade diffuser 120. In some applications, the secondary fluid is or includes exhaust gas. The injection device 130 includes a movable port 131 at least partially disposed between adjacent blade pairs 121, 122, 123 of the diffuser 120. For example, the movable port 131 may be confined by the pair of adjacent blades in one dimension (e.g., perpendicular to the flow of the primary fluid), meaning its extension in that dimension cannot exceed the adjacent blade pair. In a second dimension (e.g., parallel to the flow of the primary fluid), the movable port 131 may extend between the upstream end of one blade and the downstream end of an adjacent blade, or even from the upstream end of one blade to the downstream end of an adjacent blade. The movable port 131 may also be entirely disposed between adjacent blade pairs 121, 122, 123 of the diffuser 120. The movable port 131 is movable, meaning that at least a portion of the relative position of the port 131 with respect to the blade diffuser can be changed. For example, the port 131 can be moved by rotation or translation.

[0030] According to another embodiment, the injection device 130 includes a movable port 131 at least partially disposed between multiple pairs of adjacent blade pairs 121, 122, 123. A downstream portion or downstream end of the movable port 131 may extend over all or part of the circumference of the blade diffuser 120. For example, as Figure 2A In an alternative embodiment shown, the movable port 131 may be partially disposed between adjacent blades 121, 122, and partially disposed between adjacent blades 122, 123, and extend downstream of blade 122 (or in other words, the movable port 131, as in...). Figure 2A The diagram shows several individual ports 131, which may include sections connected at the downstream end or integrally formed, particularly approximately perpendicular to the flow of the primary fluid.

[0031] The injection device 130 can be configured to inject secondary fluid into the blade diffuser 120 when the movable port 131 is in the open position, and to prevent secondary fluid from flowing into the blade diffuser 120 when the movable port 131 is in the closed position. The movable port 131 is partially disposed between adjacent blade pairs, allowing secondary fluid to be injected at a low back pressure position of the primary fluid. The relatively low static pressure of the primary fluid causes the secondary fluid to be drawn into the primary fluid.

[0032] In one embodiment, the injection device 130 is configured to inject secondary fluid into the throat section 150, preferably within the upstream portion 151 and / or the throat position 152 of the throat section. This embodiment allows the secondary fluid to be injected at the location of lowest back pressure of the primary fluid. Preferably, the secondary fluid is injected between the diffuser inlet section 111 and the downstream end of the blades, near the primary fluid or even at the highest Mach number, or even within the bladed diffuser 120.

[0033] Figure 1A An embodiment is shown where a movable port 131 is disposed between adjacent blade pairs 121, 122 of diffuser 120. Figure 3B yes Figure 1A A close-up of the compressor stage 100 is shown. The outline indicates the Mach number of the primary fluid at a specific operating point. In this particular example, i.e., at this particular operating point, the highest Mach number is obtained at the upstream portion 151 of the throat position 152. At other operating points, for example, the highest Mach number may be obtained at the throat position 152. The movable port 131 is configured such that the injection position 135 is located near the highest Mach number of the primary fluid.

[0034] The embodiments of this disclosure advantageously allow the introduction of secondary gas downstream of the impeller, thereby avoiding erosion and corrosion of the impeller, while allowing for the injection of secondary fluid at a low back pressure location relative to the primary fluid. Therefore, no additional blower is required for the secondary fluid. The high-momentum primary fluid exiting the compressor impeller 110 draws in and pressurizes the secondary fluid, acting like a jet pump.

[0035] The movable port 131 according to this disclosure is configured to adjust the effective cross-section (or effective cross-sectional area) of the blade diffuser 120. Specifically, the effective cross-section between the blades 121, 122, 123 or the throat segment 150 is adjusted by shifting the port 131. Advantageously, adjustment of the cross-section of the throat segment 150 results in adjustment of the cross-section of the throat position 152. The effective cross-section of the throat position (152) is adjusted by shifting the port (131).

[0036] The bladed diffuser 120 can be designed such that the cross-sectional area, or in other words, the mass flow rate, of the throat position 152 is sufficient for the primary fluid when no secondary fluid is injected and the displaceable port 131 is in the closed position. Displacement of port 131 allows secondary fluid to be injected, which in turn results in a higher mass flow rate. Simultaneously, the effective cross-sectional area of ​​the throat position 152 increases in the open position, which advantageously allows the combined primary and secondary fluids to pass through the throat section 150 without impeding the performance of the compressor stage 100. The impeller is capable of providing the same mass flow rate with and without secondary fluid injection and can operate at its optimal performance both when the secondary flow is open and closed. By adjusting the effective cross-sectional area to the amount of secondary fluid to be injected, an ideal cross-sectional area can be ensured at each operating point.

[0037] The injection of the secondary fluid is not limited by the mass flow rate of the secondary fluid. Therefore, the movable port 131 allows for flexible flow conditions that can be adjusted according to the desired or anticipated flow rate of the secondary fluid. The compressor stage according to this disclosure overcomes the disadvantages of the constant geometry of diffusers in the prior art. The embodiments disclosed herein allow for adjustment of the diffuser geometry to inject a wide range of secondary fluid flows into the primary flow. Furthermore, it can be ensured that the increased mass flow rate can pass through the diffuser without pushing the impeller into a surge. Additionally, the port displacement allows for adjustment of the flow area variation along the streamlines within the diffuser 120.

[0038] Figure 1B Explanation Figure 1A The cross-section of compressor stage 100 along line AA. The flow of the primary fluid is... Figure 1B The large, unfilled arrow on the right indicates that, in this embodiment, the movable port 131 can be switched or moved from a closed position (movable port 131 is indicated by a thick line) to an open position (movable port 131 is indicated by a dashed line). The arrow drawn below the throat position 152 indicates the increase in cross-sectional area in the open position compared to the closed position.

[0039] According to one aspect, the injection device 130 includes a drive mechanism configured to move or translate a movable port 131 between an open position and a closed position. For example, the drive mechanism may include a hydraulic, mechanical, pneumatic, or sensor-controlled actuator. Figure 2B and 3A An example of a compressor stage including a drive mechanism (not shown in the figure) is shown. Figure 2B and 3A The left-right arrows in the diagram indicate that the displacement of the displaceable port 131 is approximately perpendicular to the flow of the primary fluid. Figure 3A In the diagram, the shiftable port 131 is indicated by a thick line in the closed position and by a dashed line in the open position. Figure 2B The left arrow in the diagram indicates the flow direction of the secondary fluid.

[0040] According to another aspect, the injection device 130 includes a pivoting mechanism configured to pivot the movable port 131 between an open position and a closed position. Figure 1B An example of a compressor stage including a pivoting mechanism is illustrated. The injection device 130 may also include one or more connectors 134 that pivotally mount the movable port 131 to the blade diffuser 120. The connectors 134 are preferably located downstream of the throat position 152, such that pivoting the movable port 131 results in a significant increase in the cross-sectional area near the throat position 152. According to this aspect, the port may also be referred to as a flap valve.

[0041] According to one aspect, the injection device 130 is configured to inject a secondary fluid substantially parallel to the flow of the primary fluid into the vane diffuser 120. The injection device may include a secondary fluid passage 132. The secondary fluid passage may be fluidly connected to a secondary fluid supplier 133. The secondary fluid passage 132 may be positioned at a small angle relative to the flow of the primary fluid. The injection device 130 may also include a flow regulator or valve. The flow regulator may be located within or upstream of the secondary fluid passage 132. The flow regulator may be configured to regulate the mass flow rate of the secondary fluid. The mass flow rate of the secondary fluid may be controlled by the flow regulator, while the effective cross-sectional area may be controlled by port 131, thereby decoupling these two functions. However, the compressor stage of this disclosure does not require a flow regulator or valve. The mass flow rate of the secondary fluid may also be controlled or regulated by shifting the port 131.

[0042] According to one aspect, the movable port 131 is disposed within the housing of the blade diffuser 120. The port 131 may be a wall segment of the blade diffuser 120. In the closed position, the port may be flush with the remaining sidewall of the blade diffuser 120. In other words, the movable port 131 does not protrude into the flow channel of the primary fluid in the blade diffuser 120 in the closed position and does not affect the flow of the primary fluid. The port 131 can be switched from the closed position to the open position by moving the port 131 away from the flow channel. The port 131 also does not protrude into the flow channel of the primary fluid in the open position. The opening movement of the port 131 corresponds to a partial retraction of the port 131 behind the remaining sidewall of the blade diffuser 120. The port 131 may be disposed within the shroud side and / or hub side of the housing. In the case where the injection device 130 includes a pivot mechanism, the downstream end of the port 131 may be flush with the remaining sidewall of the blade diffuser 120 in the open position.

[0043] Alternatively, the movable port 131 is disposed within the blades 121, 122, and 123 of the bladed diffuser 120. Typically, the blades of a bladed diffuser have a fairly limited range in the direction perpendicular to the primary fluid flow. This embodiment is particularly suitable when the cross-sectional area is appropriately varied via port 131.

[0044] Compressor stage 100 may also include a conical diffuser section 140 or a vortex housing (e.g., see reference). Figure 3A The conical diffuser section 140 is located downstream of the blade diffuser 120, particularly downstream of the downstream section 153 and upstream of the compressor stage outlet section. The length of the downstream section 153 along the flow path of the primary fluid may be greater than or equal to the distance along the flow direction of the primary fluid at the throat position 152 and the downstream end of the port 131.

[0045] The compressor stage 100 may also include a control unit. The control unit may be configured to shift port 131 (e.g., by controlling a drive mechanism or by controlling a pivot mechanism) to inject secondary fluid and / or adjust the effective cross-section of the throat section 150 to a predetermined level. The control unit may also be configured to control the mass flow rate of the secondary fluid (e.g., by controlling a flow regulator).

[0046] The blade diffuser may include a plurality of movable ports 131. Each of the plurality of movable ports 131 may be at least partially disposed between adjacent blade pairs 121, 122, 123. Figure 2A A portion of a blade diffuser 120 is shown, including three pairs of blades 121, 122, 123 and three ports 131. According to one exemplary embodiment, the blade diffuser 120 includes ports 131 disposed between each pair of adjacent blades 121, 122, 123. According to another exemplary embodiment, the multiple ports 131 may be arranged in a pattern. For example, ports 131 may be disposed between each pair of adjacent blades 121, 122, 123. The control unit may be configured to shift the multiple ports 131 and / or individually control the mass flow rate of the secondary fluid, i.e., the mass flow rates of the secondary fluid are independent of each other.

[0047] According to an embodiment, a turbocharging system is provided. The turbocharging system includes a compressor stage according to any embodiment disclosed herein. The turbocharging system includes one or more turbocharger stages. At least one of the turbocharger stages includes a compressor stage according to any embodiment disclosed herein. In one exemplary aspect, each turbocharger stage includes a compressor stage according to any embodiment disclosed herein. In another exemplary aspect, one turbocharger stage includes a compressor stage according to any embodiment disclosed herein, while other turbocharger stages may not be configured to inject secondary fluid.

[0048] According to an embodiment, an engine is provided. The engine includes a turbocharging system according to any embodiment disclosed herein. In one aspect, the engine is an internal combustion engine. The injection device 130, particularly the secondary fluid passage 132, is fluidly connected to the exhaust manifold of the engine.

[0049] According to another embodiment, a gas engine, particularly a hydrogen combustion engine, is provided. The gas engine includes a compressor stage according to any embodiment disclosed herein. The injection device 130, particularly the secondary fluid passage 132, can be fluidly connected to the exhaust outlet of the gas engine.

[0050] According to another embodiment, a fuel cell, particularly a hydrogen fuel cell, is provided. The fuel cell includes a compressor stage according to any embodiment disclosed herein. An injection device 130, particularly a secondary fluid channel 132, is fluidly connected to the exhaust outlet of the fuel cell. In one aspect, the fuel cell is a proton exchange membrane fuel cell or a polymer electrolyte membrane fuel cell (PEMFC). The injection device 130, particularly the secondary fluid channel 132, is fluidly connected to a secondary fluid supply device 133. The secondary fluid is preferably water (liquid water and / or water vapor), and the secondary fluid supply device 133 is a water supply device. Injecting water through the injection device 130 allows for the provision of moisture or humidification to at least one membrane of the fuel cell. Advantageously, supplying humidifying water to at least one membrane of the fuel cell through the compressor stage allows for improved water distribution within the fuel cell core, and even management of water distribution within the fuel cell core. Simultaneously, injecting water downstream of the impeller of the compressor stage avoids or at least mitigates erosion and corrosion problems of the impeller.

[0051] According to another embodiment, a fuel cell, particularly a hydrogen fuel cell, is provided. The fuel cell includes a compressor stage according to any embodiment disclosed herein. An injection device 130, particularly a secondary fluid channel 132, can be fluidly connected to one or more (dedicated) tanks. In one aspect, the fuel cell is a proton exchange membrane fuel cell or a polymer electrolyte membrane fuel cell (PEMFC). The injection device 130, particularly the secondary fluid channel 132, is fluidly connected to a secondary fluid supply device 133. The secondary fluid is preferably water (liquid water and / or water vapor), and the secondary fluid supply device 133 is a water supply device. Injecting water through the injection device 130 allows for the supply of moisture or humidification to at least one electrolyte membrane of the fuel cell. Advantageously, supplying humidifying water to at least one membrane of the fuel cell through the compressor stage allows for improved water distribution within the fuel cell core, and even better management of water distribution within the fuel cell core. Simultaneously, injecting water downstream of the impeller of the compressor stage avoids or at least mitigates erosion and corrosion problems of the impeller. At least one tank may be connected to one or more condensers and / or one or more separators of the fuel cell to recover water from any water source of the fuel cell. At least one tank may preferably be partially or completely filled with water from an external source of the fuel cell. The injection device 130 may be configured to supply water directly from any of one or more condensers and / or from any of one or more separators and / or from any of one or more tanks.

[0052] The compressor stage and / or turbocharger system according to any embodiment disclosed herein can be used in a variety of applications, including automotive or industrial applications. While the background section emphasizes exhaust gas recirculation in internal combustion engines as a potential application area, the embodiments disclosed herein are not limited to applications in internal combustion engines, or even to exhaust gases. The compressor stage disclosed herein can also inject other secondary fluids, such as air, gaseous fuel, or air-fuel mixtures.

[0053] According to another embodiment, a method is provided for operating a compressor stage of a turbocharger system and / or a turbocharger compound. The compressor stage can be any compressor stage described herein.

[0054] The method includes determining the expected mass flow rate of the secondary fluid. Typically, the expected mass flow rate corresponds to a value predetermined by the user or manufacturer. For example, for applications utilizing internal combustion engines, the expected mass flow rate might be a determined mass flow rate of exhaust gas required to ensure compliance with environmental regulations.

[0055] The method also includes determining the effective cross-section of the compressor's bladed diffuser 120 to keep the impeller 110 of the compressor stage 100 within predetermined operating limits. Typically, the impeller 110 can only operate within certain operating limits without impairing its performance. If the mass flow rate of the secondary fluid increases significantly without changing other impeller parameters, such as the geometry of the primary fluid flow path, the increased mass flow rate may push the impeller towards a surge. The required effective cross-section is determined based on the expected mass flow rate of the secondary fluid and the predetermined operating limits.

[0056] The method further includes adjusting the cross-section of the blade diffuser 120 to an effective cross-section. The cross-sectional area can be adjusted by shifting a movable port 131 of the injection device 130 according to any embodiment described herein. The movable port 131 may be at least partially disposed between adjacent blade pairs 121, 122, 123 of the diffuser 120.

[0057] Explanation of reference numerals in the attached figures

[0058] 100 compressor stage

[0059] 110 Impeller

[0060] 111 Diffuser Inlet Section

[0061] 120-blade diffuser

[0062] 121, 122, 123 Leaf blades

[0063] 130 Injection Device

[0064] 131 Displaceable Port

[0065] 132 secondary fluid channels

[0066] 133 Secondary fluid supply

[0067] 134 connector

[0068] 140 Conical Diffuser Section / Vortex Shell

[0069] 150 Throat segment

[0070] 151 Upstream section

[0071] 152 Throat position

[0072] 153 Downstream section

Claims

1. A compressor stage (100), comprising: - an impeller (110); and - a vaned diffuser (120) arranged downstream of the impeller (110) and in fluid connection with an outlet of the impeller (110), the vaned diffuser (120) comprising an injection device (130) configured to inject a secondary fluid into the vaned diffuser (120); wherein the injection device (130) comprises a shiftable port (131) arranged at least partially between adjacent blade pairs (121, 122, 123) of the vaned diffuser (120), and wherein the shiftable port (131) is shiftable such that a relative position of at least a portion of the shiftable port (131) relative to the vaned diffuser (120) is changeable. The vaned diffuser (120) comprises a throat section (150) defined by adjacent blade pairs (121, 122, 123).

2. The compressor stage of claim 1, wherein, The injection device (130) is configured to inject the secondary fluid into the throat section (150).

3. The compressor stage of claim 2, wherein, An effective cross section of the vaned diffuser (120) is adjusted by a shifting of the shiftable port (131).

4. The compressor stage of any one of claims 1 to 3, wherein, The injection device (130) is configured to inject the secondary fluid into the vaned diffuser (120) when the shiftable port (131) is in an open position and to prevent a flow of the secondary fluid into the vaned diffuser (120) when the shiftable port (131) is in a closed position.

5. The compressor stage of any one of claims 1 to 3, wherein, The injection device (130) comprises a drive mechanism configured to move the shiftable port (131) between the open position and the closed position.

6. The compressor stage of claim 5, wherein, The injection device (130) comprises a pivot mechanism configured to pivot the shiftable port (131) between the open position and the closed position.

7. The compressor stage of claim 5, wherein, The throat section (150) comprises an upstream portion (151) adjacent to a diffuser inlet section (111), a throat location (152), and a downstream portion (153).

8. The compressor stage of claim 2, wherein, The injection device (130) is configured to inject the secondary fluid within the upstream portion (151) and / or within the throat location (152).

9. The compressor stage of claim 8, wherein, The secondary fluid is exhaust gas.

10. The compressor stage of any one of claims 1 to 3, wherein, The injection device (130) is configured to inject the secondary fluid in the vaned diffuser (120) substantially parallel to a flow of a primary fluid.

11. The compressor stage of any one of claims 1 to 3, wherein, The shiftable port (131) is arranged within a housing of the vaned diffuser (120).

12. The compressor stage of any one of claims 1 to 3, wherein, Each of the plurality of shiftable ports (131) is arranged at least partially between adjacent blade pairs (121, 122, 123).

13. The compressor stage of any one of claims 1 to 3, further comprising a plurality of displaceable ports (131), wherein, The compressor stage is for a turbocharging system and / or a turbo compound.

14. The compressor stage of any one of claims 1 to 3, wherein, An effective cross section of the throat section (150) is adjusted by a shifting of the shiftable port (131).

15. The compressor stage of claim 2, wherein, The injection device (130) is configured to inject the secondary fluid within the upstream portion (151) and / or within the throat location (152) in a vicinity of a maximum velocity of the primary fluid conveyed through the vaned diffuser (120).

16. The compressor stage of claim 8, wherein, ​ 17. The compressor stage of claim 12, wherein, The shiftable port (131) is arranged within a shroud side and / or a hub side of the housing.

18. A turbocharger system comprising a compressor stage (100) according to any one of claims 1-17.

19. A fuel cell comprising a compressor stage (100) according to any one of claims 1-17.

20. The fuel cell of claim 19, wherein, The fuel cell is a proton exchange membrane fuel cell, and wherein the secondary fluid is liquid water and / or water vapor.

21. The fuel cell of claim 20, wherein, The injection device (130) further comprises a liquid water and / or water vapor supply (133) for humidifying at least one membrane of a proton exchange membrane fuel cell.

22. A method for operating a compressor stage for a turbocharging system and / or a turbo compound, wherein The compressor stage is a compressor stage (100) according to any one of claims 1-17, the method comprising the following series of steps: determining an expected mass flow of a secondary fluid; determining an effective cross section of a vaned diffuser (120) of the compressor to keep an impeller (110) of the compressor within predetermined operational limits; adjusting the cross section of the vaned diffuser (120) to the effective cross section.

23. The method of claim 22, wherein, Adjusting the cross section of the vaned diffuser (120) to the effective cross section comprises adjusting the cross section of the vaned diffuser (120) to the effective cross section by shifting a shiftable port (131) of the injection device (130) arranged at least partially between adjacent blade pairs (121, 122, 123) of the vaned diffuser (120).

24. The method of claim 22, wherein, The secondary fluid is exhaust gas.

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