Compressor housing, supercharger and method of operating a supercharger

Abstract

A compressor housing that houses a compressor impeller of a supercharger, has a plurality of injection holes for injecting compressed gas toward a negative pressure surface of an impeller blade of the compressor impeller, the plurality of injection holes including at least one first injection hole and at least one second injection hole having an outlet at a position different from an outlet of the first injection hole in an axial direction of the compressor impeller.

Description

Technical Field

[0001] This invention relates to a compressor housing, a booster, and a method for operating the booster.

[0002] This application is based on and claims priority to Japan Patent Application No. 2021-050932 filed with the Japan Patent Office on March 25, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] During engine startup, less exhaust gas flows from the engine to the turbocharger. Furthermore, due to the inertia of the turbocharger's rotating components, the turbocharger performs less work, resulting in a smaller amount of compressed air being delivered from the turbocharger to the engine. Consequently, black smoke is sometimes emitted from the engine. To suppress this black smoke emission and improve turbocharger efficiency by enhancing its load responsiveness (speed increase) during engine startup, a method exists where compressed gas is injected into the impeller blades of the compressor impeller through injection holes in an air guide tube located in the compressor housing.

[0004] Patent Document 1 describes a method for increasing engine load by supplying compressed air (compressed gas) to the impeller blades of the compressor impeller through numerous injection holes covering the entire outer periphery of the compressor impeller located in the turbocharger, thereby obtaining the target boost air pressure.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 61-132721

[0008] The technical problem that the invention aims to solve

[0009] As the inventors of this application know, in the structure described in Patent Document 1, when compressed gas is injected near the outlet of the compressor impeller (the outer periphery of the compressor impeller), while a relatively large torque can be obtained to assist the rotation of the compressor impeller when the engine load is relatively low, such as during engine startup, the effect of assisting the rotation of the compressor impeller by compressed gas is easily limited as the engine load increases (as the speed of the turbocharger increases). Therefore, in the structure described in Patent Document 1, the range of turbocharger speeds that can assist the rotation of the compressor impeller by the injection of compressed gas is limited. Summary of the Invention

[0010] In view of the above, at least one embodiment of the present invention aims to provide a compressor housing, a booster having the compressor housing, and a method for operating the booster, which can effectively assist the rotation of the compressor impeller by compressed gas across a wide range of speeds of the booster.

[0011] Technical means for solving technical problems

[0012] To achieve the above objectives, at least one embodiment of the present invention relates to a compressor housing that is,

[0013] The compressor housing that houses the compressor impeller of the booster.

[0014] It has multiple injection holes for injecting compressed gas toward the impeller blades of the compressor impeller.

[0015] The plurality of injection holes include:

[0016] At least one first injection hole; and

[0017] At least one second injection hole has an outlet at a different location on the axial direction of the compressor impeller than the outlet of the first injection hole.

[0018] To achieve the above objectives, at least one embodiment of the turbocharger according to the present invention comprises:

[0019] The aforementioned compressor housing; and

[0020] A valve control device configured to control the at least one first valve and the at least one second valve based on the operating state of at least one of the turbocharger and the engine.

[0021] To achieve the above objectives, at least one embodiment of the present invention includes a method for operating a turbocharger comprising the following steps:

[0022] The first injection hole injection step involves injecting compressed gas from a first injection hole located on the compressor housing of the booster toward the impeller blades of the compressor impeller; and

[0023] In the second injection hole injection step, compressed air is injected toward the impeller blades from a second injection hole provided in the compressor housing. The second injection hole is located axially downstream of the compressor impeller than the first injection hole.

[0024] When the turbocharger's speed is in the first speed range, the second injection orifice injection step is performed; when the turbocharger's speed is in the second speed range, the first injection orifice injection step is performed. The second speed range is a high speed range compared to the first speed range.

[0025] The effects of the invention

[0026] According to at least one embodiment of the present invention, a compressor housing, a booster having the compressor housing, and a method for operating the booster are provided, which can effectively assist the rotation of the compressor impeller by compressed gas across a wide range of speeds of the booster. Attached Figure Description

[0027] Figure 1 This is a schematic cross-sectional view of the turbocharger 2 according to one embodiment.

[0028] Figure 2 It means that it can be applied to Figure 1 A cross-sectional view of the centrifugal compressor 4 of the booster 2 shown.

[0029] Figure 3 yes Figure 2 An enlarged view of the area near the injection port 28 in the centrifugal compressor 4 shown.

[0030] Figure 4 This is a graph showing the relationship between the speed of the booster 2 when compressed air is introduced and the increase in the speed of the booster 2 caused by the introduction of compressed air.

[0031] Figure 5 This is a diagram showing an example of the static pressure distribution along the meridional distance from the leading edge 18LE to the trailing edge 18TE of the impeller blade 18.

[0032] Figure 6 This is a diagram showing an example of the circumferential configuration of the outlets 28a2 of the multiple injection holes 28.

[0033] Figure 7 This is another example of the circumferential configuration of the outlets 28a2 of the multiple injection holes 28.

[0034] Figure 8 This is a schematic diagram showing an example of the cross-sectional structure of a centrifugal compressor 4 in a booster 2 equipped with valves 36a to 36c and a valve control device 38, and is an enlarged view of the vicinity of the injection port 28.

[0035] Figure 9 This is a diagram of the determination process used to determine the injection mode executed by the valve control device 38.

[0036] Figure 10 It is a graph showing the time-series changes in the speed of the booster 2, the opening degree of valves 36a to 36c, and the amount of compressed air injected.

[0037] Figure 11 This is a diagram illustrating an example of a supercharger 2 having a closed component 42.

[0038] Figure 12This is a diagram illustrating another example of a supercharger 2 equipped with a closed component 42. Detailed Implementation

[0039] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the constituent components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0040] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configuration not only indicate such configuration in a strict sense, but also indicate the state of relative displacement by angle or distance with tolerance or to the extent that the same function can be obtained.

[0041] For example, expressions such as "same," "equal," and "homogeneous" that indicate that things are in an equal state not only indicate a state of equality in a strict sense, but also indicate a state of difference in the degree to which there is tolerance or the degree to which the same function can be obtained.

[0042] For example, the description of shapes such as quadrilaterals or cylinders not only refers to quadrilaterals or cylinders in the strict sense of geometry, but also includes shapes with concave or convex parts or chamfers within the range where the same effect can be obtained.

[0043] On the other hand, the expression "possessing," "including," or "having" a constituent element is not an exclusive expression that excludes the existence of other constituent elements.

[0044] Figure 1 This is a schematic cross-sectional view of the turbocharger 2 according to one embodiment.

[0045] like Figure 1 As shown, the supercharger 2 includes a centrifugal compressor 4 and a turbine 6.

[0046] The centrifugal compressor 4 includes a compressor impeller 8 and a compressor housing 10 that houses the compressor impeller 8. The turbine 6 includes a turbine rotor 12 and a turbine housing 14 that houses the turbine rotor 12.

[0047] The compressor impeller 8 includes a hub 16 and a plurality of impeller blades 18 spaced circumferentially on the outer peripheral surface of the hub 16. The compressor impeller 8 and the turbine rotor 12 are connected by a rotating shaft 20 and are configured to rotate integrally. The rotating shaft 20 is supported by a bearing 22 to enable rotation. The bearing 22 is housed in a bearing housing 24. The bearing housing 24 is connected to the compressor housing 10 at one axial end and to the turbine housing 14 at the other axial end.

[0048] The turbine rotor 12 is rotated by the exhaust gas of an engine (not shown), which in turn rotates the compressor impeller 8 connected to the turbine rotor 12 via the rotating shaft 20 and compresses the air. The compressed air discharged from the centrifugal compressor 4 is supplied to the engine.

[0049] Furthermore, in this specification, the axial direction of the compressor impeller 8, i.e. the axial direction of the rotating shaft 20, is simply referred to as "axial direction", the radial direction of the compressor impeller 8, i.e. the radial direction of the rotating shaft 20, is simply referred to as "radial direction", and the circumferential direction of the compressor impeller 8, i.e. the circumferential direction of the rotating shaft 20, is referred to as "circumferential direction".

[0050] Figure 2 It means that it can be applied to Figure 1 A diagram showing an example of the detailed structure of the centrifugal compressor 4 with booster 2.

[0051] exist Figure 2 In the exemplary embodiment shown, the compressor housing 10 includes an air guide tube 30 that guides air to the compressor impeller 8 and a vortex housing 34 that forms a vortex-shaped vortex flow path 32 on the outer periphery of the compressor impeller 8. The air guide tube 30 is configured in a cylindrical shape surrounding the compressor impeller 8. The inner and outer diameters of the air guide tube 30 increase axially toward the downstream side of the airflow at a position relative to the leading edge 18LE of the impeller blades 18. Furthermore, in this specification, the upstream side and the downstream side of the airflow are simply referred to as "upstream side" and "downstream side," respectively.

[0052] like Figure 2 As shown, the air guide tube 30 of the compressor housing 10 has multiple injection holes 28 for injecting compressed air toward the negative pressure surface 26 (blade surface) of the impeller blades 18 of the compressor impeller 8. The multiple injection holes 28 are through holes extending from the outer peripheral surface to the inner peripheral surface of the air guide tube 30. In the illustrated example, the multiple injection holes 28 extend through the air guide tube 30 in a straight line. Each injection hole 28 can also be configured to inject compressed air as compressed gas toward the negative pressure surface 26 in a direction perpendicular to the negative pressure surface 26 of the impeller blades 18. That is, the angle formed between the central axis of each injection hole 28 and the negative pressure surface 26 of the impeller blades 18 can be approximately 90 degrees.

[0053] Additionally, in the illustrated example, an annular space 31 for compressed air to pass through is formed between the outer peripheral surface of the air guide tube 30 and the vortex housing 34. The vortex housing 34 includes a radially extending compressed air passage 35 for supplying compressed air to the annular space 31. The compressed air passage 35 is connected to a compressed air box 46, which serves as the source of compressed air, via a compressed air line 44. A valve 45 is provided in the compressed air line 44 for controlling the supply of compressed air from the compressed air box 46. Compressed air from the compressed air box 46, having passed sequentially through the compressed air line 44, the compressed air passage 35, and the space 31, is injected from the injection port 28 toward the negative pressure surface 26 of the impeller blades 18, and functions as auxiliary air to assist the rotation of the compressor impeller 8.

[0054] As detailed below, the plurality of injection holes 28 includes a plurality of injection holes 28a, a plurality of injection holes 28b and a plurality of injection holes 28c.

[0055] Figure 3 yes Figure 2 An enlarged view of the area near the injection port 28 in the centrifugal compressor 4 shown.

[0056] like Figure 3 As shown, multiple injection holes 28a are formed in the multiple injection holes 28 at the position closest to the leading edge 18LE of the impeller blade 18.

[0057] The outlet 28a2 of the injection hole 28a is located axially between the blade tip 18LE1 of the leading edge 18LE of the impeller blade 18 and the outlet 28b2 of the injection hole 28b. Therefore, the outlet 28a2 of the injection hole 28a is located radially inward compared to the outlets 28b2 and 28c2 of the injection hole 28b, respectively. That is, the outlet 28a2 of the injection hole 28a is located on the inner circumferential side compared to the outlets 28b2 and 28c2 of the injection hole 28b, respectively. The injection hole 28a is configured to inject compressed air into the inlet side portion (inner circumferential portion of the compressor impeller 8), i.e., the portion 18i of the impeller blade 18 on the leading edge 18LE side. Multiple injection holes 28a are arranged at circumferential intervals at the same axial position. The inlets 28a1 of multiple injection holes 28a are also arranged at circumferential intervals at the same axial position. The outlets 28a2 of the multiple injection holes 28a are arranged at the same position in the axial direction and spaced apart in the circumferential direction.

[0058] Multiple injection holes 28b are formed axially between multiple injection holes 28a and multiple injection holes 28c.

[0059] The outlet 28b2 of the injection hole 28b is located axially between the outlet 28a2 of the injection hole 28a and the outlet 28c2 of the injection hole 28c. That is, the outlet 28b2 of the injection hole 28b is located downstream of the outlet 28a2 of the injection hole 28a and upstream of the outlet 28c2 of the injection hole 28c. Therefore, the outlet 28b2 of the injection hole 28b is located radially outward of the outlet 28a2 of the injection hole 28a and radially inward of the outlet 28c2 of the injection hole 28c. In other words, the outlet 28b2 of the injection hole 28b is located on the outer periphery of the injection hole 28a2 and on the inner periphery of the injection hole 28c2. The injection holes 28b are configured to inject compressed air into the intermediate portion 18m between the inlet-side portion (inner circumference of the compressor impeller 8) and the outlet-side portion (outer circumference of the compressor impeller 8), specifically between the leading edge 18LE side portion 18i and the trailing edge 18TE side portion 18o of the impeller blades 18. Multiple injection holes 28b are arranged at circumferential intervals at the same axial position. The inlets 28b1 of the multiple injection holes 28b are arranged at circumferential intervals at the same axial position. The outlets 28b2 of the multiple injection holes 28b are arranged at circumferential intervals at the same axial position.

[0060] Multiple injection holes 28c are formed in the multiple injection holes 28 at the position closest to the trailing edge 18TE of the impeller blade 18.

[0061] The outlet 28c2 of the injection orifice 28c is located axially between the outlet 28b2 of the injection orifice 28b and the tip 18TE1 of the trailing edge 18TE of the impeller blade 18. Therefore, the outlet 28c2 of the injection orifice 28c is axially located downstream of both the outlet 28a2 and the outlet 28b2 of the injection orifice 28b. Furthermore, the outlet 28b2 of the injection orifice 28b is radially outward compared to both the outlet 28a2 and the outlet 28b2 of the injection orifice 28b. That is, the outlet 28c2 of the injection orifice 28c is located on the outer periphery side compared to both the outlet 28a2 and the outlet 28b2 of the injection orifice 28b. The injection orifice 28c is configured to inject compressed air into the outlet side portion (outer periphery of the compressor impeller 8), i.e., the portion 18o of the impeller blade 18 on the trailing edge 18TE side. Multiple injection holes 28c are arranged at the same axial position and spaced apart circumferentially. The inlets 28c1 of the multiple injection holes 28c are arranged at the same axial position and spaced apart circumferentially. The outlets 28c2 of the multiple injection holes 28c are arranged at the same axial position and spaced apart circumferentially.

[0062] Here, the technical significance of providing injection holes 28a, 28b, and 28c with outlets 28a2, 28b2, and 28c2 at different axial positions as described above on the compressor housing 10 will be explained.

[0063] To the best of the inventors' knowledge, in tests conducted on conventional turbochargers, such as Figure 4 As shown, the higher the turbocharger speed when compressed air is introduced (when compressed air is injected from the injection port into the impeller blades), the smaller the speed increase effect of the turbocharger caused by the compressed air. Furthermore, this tendency remains the same even when the compressed air injection pressure is changed. Thus, when compressed air is injected into the outlet side of the compressor impeller, under low engine load conditions such as engine startup (not shown), although a large torque can be obtained to assist the rotation of the compressor impeller, the effect of assisting the compressor impeller rotation with compressed air is easily limited as the engine load increases (as the turbocharger speed increases).

[0064] This is because, as the engine load increases, the turbocharger speed increases, such as... Figure 5 As shown, the pressure increases near the compressor impeller outlet, thus reducing the amount of compressed air that can be supplied. On the other hand, according to Figure 5 It is known that even during the operation of the turbocharger, the pressure near the inlet of the compressor impeller is relatively low. Therefore, if compressed air is introduced from the inlet side, it can effectively assist the rotation of the compressor impeller and can be expected to increase the speed of the turbocharger.

[0065] Therefore, by providing injection holes 28a, 28b, and 28c with outlets 28a2, 28b2, and 28c2 at different axial positions on the compressor housing 10, for example, when the speed of the booster 2 is in the low-speed range (when the pressure at the outlet side of the compressor impeller 8 is low), compressed air is injected from the outlet 28c2 of the injection hole 28c located relatively downstream in the axial direction; when the speed of the booster 2 is in the medium-speed range, compressed air is injected from the outlet 28b2 of the injection hole 28b located in the middle in the axial direction; and when the speed of the booster is in the high-speed range (when the pressure at the outlet side of the compressor impeller 8 is high), compressed air is injected from the outlet 28a2 of the injection hole 28a located relatively upstream in the axial direction. In this way, the injection of compressed air from the injection holes 28a to 28c can be appropriately separated according to the operating state of the booster 2 (e.g., the speed of the booster 2 or the discharge pressure of the booster 2).

[0066] Therefore, compressed air can effectively assist the rotation of the compressor impeller 8 at a wide range of speeds throughout the turbocharger.

[0067] In several implementations, for example, it could also be, as follows: Figure 6 As shown, the outlets 28a2 of the plurality of injection holes 28a have equal intervals d in the circumferential direction, or for example, they may be as follows: Figure 7 As shown, the outlets 28a2 of the multiple injection holes 28a have unequal intervals d (d1, d2, d3) in the circumferential direction. Figure 6 In the example shown, the outlets 28a2 of the six injection holes 28a are arranged at 60-degree intervals in the circumferential direction. Figure 7 In the example shown, the six circumferential intervals in the six injection holes 28a include four equal intervals d1, an interval d2 smaller than interval d1, and an interval d3 larger than interval d1. Furthermore, when the outlets 28a2 of the multiple injection holes 28a have unequal intervals (unequal spacing) in the circumferential direction, the intervals of the outlets 28a2 of the multiple injection holes 28a may also differ in only one way, or as shown in... Figure 7 As shown, it contains more than three types of intervals.

[0068] The number and spacing of the multiple injection holes 28a affect the blade vibration of the impeller blades 18 of the compressor impeller 8. Assuming the outlets of the multiple injection holes 28a are arranged at equal intervals (equal spacing), it is assumed that the harmonics corresponding to the number of injection holes 28a increase. Conversely, when the outlets 28a2 of the multiple injection holes 28a have uneven spacing in the circumferential direction, the harmonics corresponding to the number of injection holes 28a are dispersed to other harmonics compared to the case of equal spacing in the circumferential direction, thus reducing the blade vibration of the impeller blades 18. Furthermore, the orifice diameter, number, and spacing of the multiple injection holes 28a can also be determined considering the effect on the rotation of the compressor impeller 8 and the strength of the rotating body including the compressor impeller 8 and the turbine rotor 12. For example, if the orifice diameter of the multiple injection holes 28a is reduced, the compressed air velocity increases, which is expected to increase the effect on the rotation of the compressor impeller 8; on the other hand, the load applied to the rotating body increases.

[0069] Similarly, for the injection holes 28b, the outlets 28b2 of the multiple injection holes 28b can have equal or unequal spacing in the circumferential direction. Furthermore, when the outlets 28b2 of the multiple injection holes 28b have unequal spacing in the circumferential direction (unequal intervals), the spacing of the outlets 28b2 of the multiple injection holes 28b can be only one different, or it can include three or more different spacings. When the outlets 28b2 of the multiple injection holes 28b have unequal spacing in the circumferential direction, the harmonics corresponding to the number of injection holes 28b are dispersed to other harmonics compared to the case where the spacing is equal in the circumferential direction. Therefore, the blade vibration of the impeller blades 18 can be reduced. Moreover, the diameter, number, and spacing of the multiple injection holes 28b can also be determined by considering the effect on the rotation of the compressor impeller 8 and the strength of the rotating body including the compressor impeller 8 and the turbine rotor 12.

[0070] Similarly, for the injection holes 28c, the outlets 28c2 of the multiple injection holes 28c can have equal or unequal spacing in the circumferential direction. Furthermore, when the outlets 28c2 of the multiple injection holes 28c have unequal spacing in the circumferential direction (unequal intervals), the spacing of the outlets 28c2 of the multiple injection holes 28c can be only one different, or it can include three or more different spacings. When the outlets 28c2 of the multiple injection holes 28c have unequal spacing in the circumferential direction, the harmonics corresponding to the number of injection holes 28c are dispersed to other harmonics compared to the case where the spacing is equal in the circumferential direction. Therefore, the blade vibration of the impeller blades 18 can be reduced. Moreover, the diameter, number, and spacing of the multiple injection holes 28c can be determined by considering the effect on the rotation of the compressor impeller 8 and the strength of the rotating body including the compressor impeller 8 and the turbine rotor 12.

[0071] In several implementations, such as Figure 8 As shown, using Figures 1 to 7 The centrifugal compressor 4 of the supercharger 2 described herein may further include: a valve 36a for controlling the injection of compressed air from the injection port 28a; a valve 36b for controlling the injection of compressed air from the injection port 28b; a valve 36c for controlling the injection of compressed air from the injection port 28c; a valve control device 38 configured to control these valves 36a, 36b, 36c, and 45 respectively according to the operating state of the supercharger 2; and a tachometer 40 for measuring the rotational speed of the supercharger 2 (the rotational speed of the rotating shaft 20). Valve 36a may be provided in each of a plurality of injection ports 28a spaced apart in the circumferential direction, valve 36b may be provided in each of a plurality of injection ports 28b spaced apart in the circumferential direction, and valve 36c may be provided in each of a plurality of injection ports 28c spaced apart in the circumferential direction.

[0072] The valve control device 38 can be constructed by a circuit or by a computer. When the valve control device 38 is constructed by a computer, it has storage devices such as RAM (Random Access Memory) and ROM (Read Only Memory) and a processor such as a CPU (Central Processing Unit), and performs its functions by executing programs stored in the storage devices.

[0073] The valve control device 38 is configured to execute the injection mode of injection hole 28a, injection mode of injection hole 28b, and injection mode of injection hole 28c.

[0074] The injection mode of injection orifice 28a is a mode in which compressed air is injected from multiple injection orifices 28a toward the negative pressure surface 26 of the impeller blades 18, and compressed air is not injected from multiple injection orifices 28b and multiple injection orifices 28c. In the injection mode of injection orifice 28a, valve control device 38 controls valve 36a to be in the open state, and controls valves 36b and 36c to be in the closed state respectively.

[0075] The injection mode of injection orifice 28b is a mode in which compressed air is injected from multiple injection orifices 28b toward the negative pressure surface 26 of the impeller blades 18, and compressed air is not injected from multiple injection orifices 28a and multiple injection orifices 28c. In the injection mode of injection orifice 28b, valve control device 38 controls valve 36b to be open and controls valves 36a and 36c to be closed respectively.

[0076] The injection mode of injection orifice 28c involves injecting compressed air from multiple injection orifices 28c toward the negative pressure surface 26 of the impeller blades 18, without injecting compressed air from multiple injection orifices 28a and 28b. In the injection mode of injection orifice 28c, valve control device 38 controls valve 36c to be open and valves 36a and 36b to be closed. When executing injection modes of injection orifice 28a, injection mode of injection orifice 28b, and injection mode of injection orifice 28c respectively, valve control device 38 controls valve 45 to be open.

[0077] When the turbocharger 2 speed measured by the tachometer 40 is in the low-speed range (equivalent to the speed range of an engine during startup or idling, not shown), the valve control device 38 executes the injection mode of injection orifice 28c. When the turbocharger 2 speed measured by the tachometer 40 is in the mid-speed range, which is higher than the low-speed range, the valve control device 38 executes the injection mode of injection orifice 28b. When the turbocharger 2 speed measured by the tachometer 40 is in the high-speed range, which is higher than the mid-speed range, the valve control device 38 executes the injection mode of injection orifice 28a. The low-speed range, mid-speed range, and high-speed range, for example, refer to the turbocharger 2 speed range when the engine is operating at a load of less than 30% of its rated load, the turbocharger 2 speed range when the engine is operating at a load of 30% to 60% of its rated load, and the turbocharger 2 speed range when the engine is operating at a load of more than 60% of its rated load, respectively.

[0078] Here, use Figure 9 and Figure 10 An example of the control flow of valve control device 38 will be described.

[0079] For example, such as Figure 9 As shown, in S11, the valve control device 38 determines whether the speed of the turbocharger 2 measured by the tachometer 40 is below a first threshold N1 (e.g., the speed of the turbocharger 2 when the engine is operating at a load of 30% relative to the rated load).

[0080] In S11, when the turbocharger 2 speed is below the first threshold N1 (when the turbocharger 2 speed is in the low speed range), in S12, the valve control device 38 controls the valve as follows: Figure 10 As shown, valve 36c is controlled to the open state while valves 36a and 36b are controlled to the closed state, and valve 45 is controlled to the open state when the speed of the booster 2 increases to execute the injection mode of injection port 28c.

[0081] If the speed of the turbocharger 2 is not below the first threshold N1 in S11, in S13, it is determined whether the speed of the turbocharger 2 measured by the tachometer 40 is below the second threshold N2 (for example, the speed of the turbocharger 2 when the engine is operating at 60% of the rated load).

[0082] In S13, when the turbocharger 2 speed is below the second threshold N2 (when the turbocharger 2 speed is in the medium speed range), in S14, the valve control device 38 controls the flow as follows: Figure 10As shown, valve 36b is controlled to be open and valves 36a and 36c are controlled to be closed, and valve 45 is controlled to be open when the speed of the booster 2 increases to execute the injection mode of injection port 28b.

[0083] In S13, if the turbocharger 2 speed is not below the second threshold N2 (if the turbocharger 2 speed is in the high speed range), in S15, the valve control device 38 controls the flow as follows: Figure 10 As shown, valve 36a is controlled to be open and valves 36b and 36c are controlled to be closed, and valve 45 is controlled to be open when the speed of the booster 2 increases to execute the injection mode of injection port 28a.

[0084] By implementing such valve control, when the turbocharger 2 operates at a low speed (and the pressure at the outlet side of the compressor impeller 8 is low), compressed air is injected from the outlet 28c2 of the most downstream nozzle 28c among the multiple nozzles 28 (outlets 28a2, 28b2, 28c2), thus generating a larger torque to assist the rotation of the compressor impeller 8. Therefore, the turbocharger efficiency is improved when the turbocharger 2 operates at low speeds, and the generation of black smoke is suppressed.

[0085] Furthermore, when the turbocharger 2 operates at a medium speed, compressed air is injected from the outlet 28b2 of the central axially located injection hole 28b among the outlets 28a2, 28b2, and 28c2 of the plurality of injection holes 28. Therefore, this assists in the rotation of the compressor impeller 8 and improves the turbocharger efficiency when the turbocharger 2 operates at a medium speed.

[0086] Furthermore, since compressed air is injected from the outlet 28a2 of the most upstream nozzle 28a among the multiple nozzles 28 outlets 28a2, 28b2, and 28c2 located in the axial direction when the speed of the booster 2 is in the high speed range (when the pressure on the outlet side of the compressor impeller 8 is high), compressed air can be appropriately injected into the negative pressure surface 26 of the impeller blades 18 even when the pressure near the outlet of the compressor impeller 8 is high, effectively assisting the rotation of the compressor impeller 8.

[0087] In this way, compressed air can effectively assist the rotation of the compressor impeller 8 across a wide range of speeds, from the low-speed to the high-speed range of the turbocharger 2. Therefore, the generation of black smoke when the turbocharger 2 is in the low-speed range can be suppressed, and high turbocharger efficiency can be achieved across all speed ranges of the turbocharger 2.

[0088] In addition, although Figure 8In the example shown, the decision to execute injection mode 28a, injection mode 28b, or injection mode 28c is based on the turbocharger 2's rotational speed measured by tachometer 40. However, in other embodiments, tachometer 40 may not be necessary. For example, the relationship between engine load or speed and turbocharger 2's rotational speed could be pre-determined, and this relationship could be used to convert the engine load or speed into turbocharger 2's rotational speed, with the result used for execution. Figure 9 The process is shown. That is, the valve control device 38 can be configured to control the valves 36a, 36b, 36c and 45 respectively according to the engine's operating state (e.g., engine load or speed), or it can be configured to control the valves 36a, 36b, 36c and 45 respectively according to at least one of the turbocharger's operating state and the engine's operating state.

[0089] Additionally, using Figure 9 The first threshold N1 and the second threshold N2 do not necessarily need to be fixed values, and can be adjusted according to the operating status of the booster 2, environmental conditions, etc.

[0090] The present invention is not limited to the embodiments described above, but also includes modifications to the embodiments described above, and appropriate combinations thereof.

[0091] For example, although in Figure 8 In the example shown, the opening degree of valves 36a to 36c is automatically changed by valve control device 38, but the opening degree of valves 36a to 36c can also be changed manually.

[0092] In several implementations, such as Figure 11 and 12 As shown, the turbocharger 2 may also include a sealing member 42 that closes at least one of the plurality of injection holes 28 instead. Figure 8 The valves 36a to 36c and the valve control device 38 are shown.

[0093] exist Figure 11 and Figure 12 In the respective exemplary embodiments shown, the turbocharger 2 includes a plurality of sealing components 42a that close the plurality of injection holes 28a and a plurality of sealing components 42b that close the plurality of injection holes 28b.

[0094] exist Figure 11 In the example shown, the sealing components 42a and 42b are respectively configured as flange-shaped cover components, and are fixed to the outer peripheral surface of the air guide cylinder 30 using fasteners such as bolts (not shown). Figure 12In the example shown, the inner circumferential surfaces of each of the injection holes 28 are machined into internal threads, and the sealing member 42a is machined into external threads so as to engage with the internal threads of the inner circumferential surface of the injection hole 28a. The sealing member 42b is machined into external threads so as to engage with the internal threads of the inner circumferential surface of the injection hole 28b. In this case, the sealing members 42a and 42b function as plugs that can close the injection holes 28a and 28b, respectively.

[0095] With the structure of such a sealing component 42, the injection port 28 (in the illustrated example, injection port 28c) can be selected according to the operating environment and specifications of the booster 2, and injection ports 28 other than the selected injection port 28 can be sealed. Therefore, since the position of the sealing component 42 can be changed after the booster 2 leaves the factory, compressed gas can be used to effectively assist the rotation of the compressor impeller 8 according to the operating environment and specifications of the booster 2.

[0096] In addition, although in the above embodiment, multiple injection holes 28 are provided at three positions along the axial direction of the air guide cylinder 30 and are spaced apart in the circumferential direction, it is also possible to provide only one injection hole 28 at each of the three positions along the axial direction of the air guide cylinder 30 in the circumferential direction.

[0097] Alternatively, at least one injection hole 28 may be provided at two positions in the axial direction in the air guide cylinder 30, or at least one injection hole 28 may be provided at four or more positions.

[0098] In addition, although Figure 1 In the supercharger 2 shown, a radial turbine is exemplified as turbine 6, but turbine 6 can also be an axial turbine.

[0099] In addition, although compressed air is used as the compressed gas injected from the injection port 28 in the above embodiment, other compressed gases besides compressed air may be used in other embodiments.

[0100] Additionally, valve 36a can be provided in each of the plurality of injection holes 28a, or one valve 36a can be provided relative to the plurality of injection holes 28a. Valve 36b can be provided in each of the plurality of injection holes 28b, or one valve 36b can be provided relative to the plurality of injection holes 28b. Valve 36c can be provided in each of the plurality of injection holes 28c, or one valve 36c can be provided relative to the plurality of injection holes 28c. When valve 36a is provided in each of the plurality of injection holes 28a, the opening and closing times of these plurality of valves 36a can also be the same. When valve 36b is provided in each of the plurality of injection holes 28b, the opening and closing times of these plurality of valves 36b can also be the same. When valve 36c is provided in each of the plurality of injection holes 28c, the opening and closing times of these plurality of valves 36c can also be the same.

[0101] The contents described in the above embodiments are as follows.

[0102] (1) The compressor housing (e.g., the compressor housing 10 described above) according to at least one embodiment of the present invention is a compressor housing that houses the compressor impeller (e.g., the compressor impeller 8 described above) of the booster (e.g., the booster 2 described above), and has a plurality of injection holes (e.g., injection holes 28 (28a~28c) described above) for injecting compressed gas (e.g., compressed air described above) toward the impeller blades (e.g., the impeller blades 18 described above) of the compressor impeller.

[0103] The plurality of injection holes include:

[0104] At least one first injection hole (e.g., the plurality of injection holes 28a, the plurality of injection holes 28b, or the plurality of injection holes 28c described above); and

[0105] At least one second injection hole (e.g., any one of the plurality of injection holes 28a, 28b, and 28c mentioned above, other than the injection hole corresponding to the first injection hole) has an outlet (e.g., any one of the outlets 28a2, 28b2, and 28c2 mentioned above, other than the outlet corresponding to the outlet of the first injection hole) at a different position in the axial direction of the compressor impeller.

[0106] In previous tests on turbochargers, the higher the turbocharger speed at the time of compressed air injection (when compressed air is injected from the injection port onto the impeller blades), the smaller the speed increase effect of the compressed air on the turbocharger. Furthermore, this tendency remained the same even when the compressed air injection pressure was varied. Thus, when compressed air is partially injected onto the outlet side (the trailing edge of the impeller blades) of the compressor impeller, under conditions of low engine load during engine startup (not shown), although a large torque can be obtained to assist the rotation of the compressor impeller, the effect of compressed air in assisting the rotation of the compressor impeller is easily limited as the engine load increases (as the turbocharger speed increases).

[0107] This is because as the engine load increases, the turbocharger speed increases, and the pressure near the compressor impeller outlet becomes higher, thus reducing the amount of compressed air that can be introduced. On the other hand, since the pressure near the compressor impeller inlet is relatively low even during turbocharger operation, introducing compressed air from the inlet side can effectively assist the compressor impeller rotation and can be expected to increase the turbocharger speed.

[0108] Therefore, the compressor housing described in (1) above, as an injection hole for injecting compressed gas into the impeller blades, includes at least one first injection hole and at least one second injection hole, the at least one second injection hole having an outlet at a position different from the outlet of the first injection hole in the axial direction of the compressor impeller. Since the inner diameter of the compressor housing of the booster increases in the axial direction of the compressor impeller towards the downstream side, the outlets of the first and second injection holes are also at different positions in the radial direction.

[0109] Therefore, for example, when the turbocharger rotates at a low speed (when the pressure near the outlet of the compressor impeller is low), compressed gas is injected from the outlet of the downstream side of the first injection hole and the outlet of the second injection hole in the axial direction. When the turbocharger rotates at a high speed (when the pressure near the outlet of the compressor impeller is high), compressed gas is injected from the outlet of the upstream side of the first injection hole and the outlet of the second injection hole in the axial direction. In this way, the injection of compressed gas from the first injection hole and the injection of compressed gas from the second injection hole can be appropriately separated according to the operating state of the turbocharger.

[0110] Therefore, compressed gas can be used to effectively assist the rotation of the compressor impeller at a wide range of speeds throughout the turbocharger.

[0111] (2) In several embodiments, in the compressor housing described in (1) above,

[0112] It also includes: at least one first valve (e.g., valve 36a, valve 36b, or valve 36c as described above), the at least one first valve being used to control the injection of the compressed gas from the at least one first injection port; and at least one second valve (e.g., any valve other than the valve corresponding to the first valve among valves 36a, valve 36b, and valve 36c as described above), the at least one second valve being used to control the injection of the compressed gas from the at least one second injection port.

[0113] According to the compressor housing described in (2) above, for example, when the speed of the booster is low (when the pressure near the outlet of the compressor impeller is low), the valve corresponding to the downstream side of the injection hole in the axial direction of the outlet of the first injection hole and the outlet of the second injection hole is set to the open state and compressed gas is injected. When the speed of the booster is high (when the pressure near the outlet of the compressor impeller is high), the valve corresponding to the upstream side of the injection hole in the axial direction of the outlet of the first injection hole and the outlet of the second injection hole is set to the open state and compressed gas is injected. In this way, the injection of compressed gas from the first injection hole and the injection of compressed gas from the second injection hole can be appropriately separated according to the operating state of the booster.

[0114] Therefore, compressed gas can be used to effectively assist the rotation of the compressor impeller across a wide range of speeds throughout the turbocharger.

[0115] (3) In several embodiments, in the compressor housing described in (1) above,

[0116] It also includes a sealing component that seals the first injection hole or the second injection hole.

[0117] According to the compressor housing described in (3) above, by using a sealing component to seal the first or second injection port, the injection port to be used can be selected according to the operating environment and specifications of the booster. Thus, compressed gas can be used to effectively assist the rotation of the compressor impeller according to the operating environment and specifications of the booster.

[0118] (4) In several embodiments, in the compressor housing described in any of (1) to (3) above,

[0119] The at least one first injection hole includes a plurality of first injection holes (e.g., the plurality of injection holes 28a, the plurality of injection holes 28b, or the plurality of injection holes 28c described above) arranged circumferentially spaced apart.

[0120] The outlets of the plurality of first injection holes have uneven spacing in the circumferential direction.

[0121] According to the compressor housing described in (4) above, compared to the case where the outlets of the multiple first injection holes are evenly spaced in the circumferential direction, the harmonics corresponding to the number of first injection holes are dispersed to other harmonics. Therefore, the blade vibration of the impeller blades can be reduced.

[0122] (5) In several embodiments, in the compressor housing described in any of (1) to (4) above,

[0123] The plurality of injection holes are configured to inject compressed gas onto the impeller blades in a direction perpendicular to the blade surface of the impeller blades.

[0124] According to the compressor housing described in (5) above, the energy of the compressed gas can be effectively converted into the rotational energy of the compressor impeller, which can effectively assist the rotation of the compressor impeller.

[0125] (6) The turbocharger according to at least one embodiment of the present invention comprises:

[0126] The compressor housing described in (2) above; and

[0127] A valve control device (such as the valve control device described above) configured to control the at least one first valve and the at least one second valve according to the operating state of at least one of the turbocharger and the engine.

[0128] According to the compressor housing described in (6) above, by appropriately opening and closing the first valve and the second valve by the valve control device according to the operating state of the booster, the injection of compressed gas from the first injection hole and the injection of compressed gas from the second injection hole can be appropriately controlled according to the operating state of the booster, thereby effectively assisting the rotation of the compressor impeller.

[0129] (7) In several embodiments, in the booster described in (6) above,

[0130] The outlet of the second injection hole is located downstream of the outlet of the first injection hole in the axial direction.

[0131] The valve control device is configured to execute a first injection orifice injection mode (e.g., the injection orifice 28b or injection orifice 28c described above) and a second injection orifice injection mode (e.g., any injection mode other than the one corresponding to the first injection orifice mode, either the injection orifice 28a or injection orifice 28b described above). The first injection orifice injection mode is a mode in which compressed gas is injected from the first injection orifice toward the impeller blades of the compressor impeller, and the second injection orifice injection mode is a mode in which compressed gas is injected from the second injection orifice toward the impeller blades of the compressor impeller.

[0132] The valve control device executes the second injection port injection mode when the speed of the turbocharger is in the first speed range (e.g., the low speed range or medium speed range mentioned above), and executes the first injection port injection mode when the speed of the turbocharger is in the second speed range (e.g., the medium speed range or high speed range mentioned above, and a speed range that does not correspond to the first speed range). The second speed range is a high speed range compared to the first speed range.

[0133] According to the turbocharger described in (7) above, when the turbocharger speed is in a relatively small first speed range (when the pressure near the compressor impeller outlet is low), compressed gas is injected from the outlet of the second injection hole, which is located on the axially downstream side (high-pressure side) of the outlet of the first injection hole and the outlet of the second injection hole. This allows for the generation of a larger torque to assist the rotation of the compressor impeller. Therefore, the turbocharger efficiency can be improved when the turbocharger speed is in a relatively small first speed range, and the generation of black smoke can be suppressed.

[0134] Furthermore, when the turbocharger's rotational speed is in a relatively high second rotational speed range (when the pressure near the compressor impeller outlet is high), compressed gas is injected from the outlet of the first injection hole, which is located on the upstream side of the first injection hole in the axial direction, between the outlet of the first injection hole and the outlet of the second injection hole. Therefore, even when the pressure near the compressor impeller outlet is high, compressed gas can still be injected into the impeller blades from the outlet of the first injection hole, which is located on the inner circumferential side (low-pressure side) relative to the outlet of the second injection hole. This allows for the appropriate injection of compressed gas into the impeller blades, effectively assisting the rotation of the compressor impeller.

[0135] In this way, compressed gas can be used to effectively assist the rotation of the compressor impeller across a wide range of speeds throughout the turbocharger.

[0136] (8) The method of operating the turbocharger according to at least one embodiment of the present invention comprises the following steps:

[0137] In the first injection hole injection step (e.g., S12 or S14 above), compressed gas (e.g., compressed air) is injected from a first injection hole (e.g., injection hole 28a or injection hole 28b above) provided in the compressor housing (e.g., compressor housing 10 above) toward the impeller blades (e.g., impeller blades 18 above) of the compressor impeller (e.g., compressor impeller 8 above); and

[0138] In the second injection hole injection step (e.g., S14 or S15 described above), compressed air is injected toward the impeller blades from a second injection hole (e.g., injection hole 28b or injection hole 28c described above) provided in the compressor housing. The second injection hole is located axially downstream of the compressor impeller than the first injection hole.

[0139] When the speed of the turbocharger is in the first speed range (e.g., the low speed range or medium speed range mentioned above), the second injection hole injection step is performed; when the speed of the turbocharger is in the second speed range (e.g., the medium speed range or high speed range mentioned above), the first injection hole injection step is performed. The second speed range is a high speed range compared to the first speed range.

[0140] According to the turbocharger operation method described in (8) above, when the turbocharger speed is in a relatively small first speed range (when the pressure near the compressor impeller outlet is low), compressed gas is injected from the outlet of the second injection hole located on the axially downstream side (high-pressure side) of the outlet of the first injection hole and the outlet of the second injection hole, thereby obtaining a larger torque to assist the rotation of the compressor impeller. Therefore, the turbocharger efficiency can be improved when the turbocharger speed is in a relatively small first speed range, and the generation of black smoke can be suppressed.

[0141] Furthermore, when the turbocharger's rotational speed is in a relatively high second rotational speed range (when the pressure near the compressor impeller outlet is high), compressed gas is injected from the outlet of the first injection hole, which is located on the upstream side (low-pressure side) of the first and second injection holes in the axial direction. Therefore, even when the pressure on the compressor impeller outlet side is high, compressed gas can still be injected into the impeller blades from the outlet of the first injection hole, which is located on the inner circumferential side relative to the outlet of the second injection hole. This allows for the appropriate injection of compressed gas into the impeller blades, effectively assisting the rotation of the compressor impeller.

[0142] In this way, compressed gas can be used to effectively assist the rotation of the compressor impeller across a wide range of speeds throughout the turbocharger.

[0143] Symbol Explanation

[0144] 2. Intensifier

[0145] 4. Centrifugal compressor

[0146] 6 turbines

[0147] 8. Compressor impeller

[0148] 10 Compressor housing

[0149] 12 turbine rotors

[0150] 14 Turbine housing

[0151] 16-inch wheels

[0152] 18 Impeller blades

[0153] 18LE Front

[0154] 18LE1 leaf tip

[0155] 18TE trailing edge

[0156] 18TE1 blade tip

[0157] 18i Leading edge side portion

[0158] 18m middle section

[0159] 18° rear edge side portion

[0160] 20 Rotation axis

[0161] 22 bearings

[0162] 24 Bearing housing

[0163] 26 Negative pressure surface

[0164] Injection holes 28, 28a, 28b, 28c

[0165] Entrances 28a1, 28b1, and 28c1

[0166] Exports of 28a2, 28b2, and 28c2

[0167] 30 Air Guide Tube

[0168] 31 Space

[0169] 32 Vortex Flow Path

[0170] 34. Scroll shell

[0171] 35 Compressed air passage

[0172] Valves 36a, 36b, and 36c

[0173] 38 Valve control device

[0174] 40 tachometer

[0175] 42, 42a, 42b Enclosed components

[0176] 44 Compressed air circuit

[0177] 45 valve

[0178] 46 Compressed Air Box

Claims

1. A compressor housing housing a compressor impeller of a booster, characterized in that, It has multiple injection holes for injecting compressed gas toward the impeller blades of the compressor impeller. The plurality of injection holes include: At least one first injection hole; and At least one second injection hole has an outlet at a position on the axial direction of the compressor impeller that is different from the outlet of the first injection hole. The compressor housing further comprises: at least one first valve for controlling the injection of compressed gas from the at least one first injection port; and at least one second valve for controlling the injection of compressed gas from the at least one second injection port.

2. A compressor housing housing a compressor impeller of a booster, characterized in that, It has multiple injection holes for injecting compressed gas toward the impeller blades of the compressor impeller. The plurality of injection holes include: At least one first injection hole; and At least one second injection hole has an outlet at a position on the axial direction of the compressor impeller that is different from the outlet of the first injection hole. The compressor housing also includes a sealing component that seals one of the first injection hole and the second injection hole.

3. A compressor housing housing a compressor impeller of a booster, characterized in that, It has multiple injection holes for injecting compressed gas toward the impeller blades of the compressor impeller. The plurality of injection holes include: At least one first injection hole; and At least one second injection hole has an outlet at a position on the axial direction of the compressor impeller that is different from the outlet of the first injection hole. The at least one first injection hole includes a plurality of first injection holes arranged at intervals in the circumferential direction. The outlets of the plurality of first injection holes have uneven spacing in the circumferential direction.

4. The compressor housing according to any one of claims 1 to 3, characterized in that, The plurality of injection holes are configured to inject compressed gas onto the impeller blades in a direction perpendicular to the blade surface of the impeller blades.

5. A booster, characterized in that, have: The compressor housing as claimed in claim 1; and A valve control device configured to control the at least one first valve and the at least one second valve based on the operating state of at least one of the turbocharger and the engine.

6. The booster according to claim 5, characterized in that, The outlet of the second injection hole is located downstream of the outlet of the first injection hole in the axial direction. The valve control device is configured to execute a first injection orifice injection mode and a second injection orifice injection mode. The first injection orifice injection mode is a mode in which compressed gas is injected from the first injection orifice toward the impeller blades of the compressor impeller, and the second injection orifice injection mode is a mode in which compressed gas is injected from the second injection orifice toward the impeller blades of the compressor impeller. The valve control device executes the second injection port injection mode when the turbocharger's speed is in the first speed range, and executes the first injection port injection mode when the turbocharger's speed is in the second speed range, wherein the second speed range is a high speed range compared to the first speed range.

7. A method for operating a turbocharger, characterized in that, The following steps are required: In the first injection hole injection step, compressed gas is injected from the first injection hole provided in the compressor housing of the booster toward the impeller blades of the compressor impeller; as well as In the second injection hole injection step, compressed air is injected toward the impeller blades from a second injection hole provided in the compressor housing. The second injection hole is located axially downstream of the compressor impeller than the first injection hole. When the turbocharger's speed is in the first speed range, the second injection orifice injection step is performed; when the turbocharger's speed is in the second speed range, the first injection orifice injection step is performed. The second speed range is a high speed range compared to the first speed range.

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