Turbocharger compressor with adjustable trim mechanism

Abstract

A turbocharger compressor having an adjustable TRIM mechanism. Specifically disclosed is a centrifugal compressor for a turbocharger including an inlet TRIM mechanism operable to move between an open position and a closed position. The inlet TRIM mechanism includes a plurality of vanes disposed about the compressor air inlet and within an annular space within the air inlet wall. The vanes are pivotable about respective pivot points such that when the vanes are in the closed position, the vanes extend radially inward from the annular space into the air inlet forming an orifice having a reduced diameter relative to the nominal diameter of the inlet. The vanes include link arms that engage an outer perimeter of a rotatable coordination ring that is coupled to a linear actuator to rotate the coordination ring to thereby pivot the vanes.

Description

Technical Field

[0001] This disclosure relates to centrifugal compressors, such as centrifugal compressors used in turbochargers, and more specifically to centrifugal compressors whose effective inlet area or diameter can be adjusted for different operating conditions. Background Technology

[0002] An exhaust-driven turbocharger is a device used in conjunction with an internal combustion engine to increase engine power output by compressing air supplied to the engine's intake to mix with fuel and burn in the engine. The turbocharger includes a compressor impeller mounted on one end of a shaft in a compressor housing and a turbine impeller mounted on the other end of the shaft in a turbine housing. Typically, the turbine housing is formed separately from the compressor housing, and a separate central housing connects the turbine housing and the compressor housing to house the shaft bearings. The turbine housing defines a generally annular chamber surrounding the turbine impeller and receiving exhaust gas from the engine. The turbine assembly includes nozzles leading from the chamber to the turbine impeller. Exhaust gas flows from the chamber through the nozzles to the turbine impeller, and the turbine impeller is driven by the exhaust gas. Thus, the turbine extracts power from the exhaust gas and drives the compressor. The compressor receives ambient air through an inlet in the compressor housing, and this air is compressed by the compressor impeller and then discharged from the housing to the engine's air intake.

[0003] Turbochargers typically employ centrifugal (also known as "radial") compressor impellers because centrifugal compressors can achieve relatively high pressure ratios in a compact arrangement. Intake air for the compressor is received generally axially at the inlet inducer portion of the centrifugal compressor impeller and discharged generally radially at the outlet inducer portion. Compressed air from the impeller is delivered to a turbine housing, from which air is supplied to the intake section of the internal combustion engine.

[0004] The operating range of a compressor is an important aspect of the overall performance of a turbocharger. This operating range is typically defined by the surge line and choke line on the compressor's operating chart. The compressor chart is usually represented as the pressure ratio (discharge pressure Pout divided by inlet pressure Pin) on the vertical axis relative to the corrected mass flow rate on the horizontal axis. The choke line on the compressor chart lies at high flow rates and represents the trajectory of the point of maximum mass flow rate above a certain pressure ratio; that is, for a given point on the choke line, it is impossible to increase the flow rate while maintaining the same pressure ratio because of the choke flow conditions occurring in the compressor.

[0005] The surge line lies at low flow rates and represents the locus of the minimum mass flow rate point above a certain pressure ratio where surge does not occur; that is, for a given point on the surge line, decreasing the flow rate without changing the pressure ratio or increasing the pressure ratio without changing the flow rate will result in surge. Surge is a flow instability that typically occurs when the angle of incidence of compressor blades becomes so large that significant flow separation occurs on the compressor blades. During surge, pressure fluctuations and backflow can occur.

[0006] In turbochargers of internal combustion engines, compressor surge can occur when the engine operates under high load or torque and at low engine speed, or when the engine operates at low speed and there is a high level of exhaust gas recirculation (EGR). Surge can also occur when the engine decelerates suddenly from a high speed. Extending the compressor's surge-free operating range to lower flow rates is a common goal in compressor design.

[0007] Claiming the benefit of Provisional Application No. 62 / 324,488, filed April 20, 2016, and co-pending application U.S. Patent Application No. 15 / 446,054, filed March 1, 2017, describes a mechanism and method for a centrifugal compressor that allows the surge line of the compressor to be selectively shifted to the left (i.e., surge is delayed to a lower flow rate at a given pressure ratio), the entire disclosure of which is hereby incorporated by reference. One embodiment described in the application includes a turbocharger having the following features:

[0008] A turbine housing and a turbine wheel mounted in the turbine housing and connected to a rotatable shaft to rotate therewith, the turbine housing receiving exhaust gas and supplying the exhaust gas to the turbine wheel;

[0009] A centrifugal compressor assembly includes a compressor housing and a compressor impeller mounted in the compressor housing and connected to a rotatable shaft for rotation therewith. The compressor impeller has blades and defines an inlet guide portion. The compressor housing has an air inlet wall defining an air inlet for guiding air substantially axially into the compressor impeller. The compressor housing further defines a volute for receiving compressed air discharged substantially radially outward from the compressor impeller.

[0010] A compressor inlet regulating mechanism is disposed in the air inlet of the compressor housing and is capable of pivoting radially inward and radially outward between an open position and a closed position. The inlet regulating mechanism includes a plurality of blades disposed around the air inlet and each blade is capable of pivoting about one end of the blade. When the blade is in the closed position, the blade pivots radially inward through a slot in the air inlet wall to form an orifice with a reduced diameter relative to the nominal diameter of the inlet.

[0011] The applicant is also the owner of other applications relating to other inlet regulating mechanisms employing moving blades, including U.S. Application No. 15 / 446,090, filed March 1, 2017, the entire disclosure of which is hereby incorporated by reference.

[0012] This disclosure relates to entry regulating mechanisms, typically of the type described in the aforementioned '054, '488 and '090 applications, and particularly to modifications or redesigns of such mechanisms aimed at improving certain aspects of said mechanisms. Summary of the Invention

[0013] One aspect of the aforementioned inlet regulating mechanism that seeks improvement involves the actuation force required to move the blades of the inlet regulating mechanism between an open and closed position. The inlet regulating mechanism is subjected to significant aerodynamic loads, particularly at low flow rates and high compression ratios, corresponding to the operating state where the blades are typically closed. Consequently, the blades experience a significant pressure difference between their upstream and downstream faces, causing them to press against the compressor housing structure directly adjacent to them in the downstream direction. These aerodynamic loads, combined with internal friction within the inlet regulating mechanism, act as a resistive force against the actuator that moves the mechanism between the open and closed positions. This results in a significantly large actuation force required from the actuator, meaning a larger and more expensive actuator is needed to achieve the actuation speed required for proper compressor operation.

[0014] Therefore, the applicant sought to mitigate this problem.

[0015] According to one embodiment disclosed herein, a turbocharger is described having a combination of features that cooperate to reduce the required actuator force of the inlet regulating mechanism. Therefore, a turbocharger according to an embodiment of the invention comprises:

[0016] A turbine housing and a turbine wheel mounted in the turbine housing and connected to a rotatable shaft to rotate therewith, the turbine housing receiving exhaust gas and supplying the exhaust gas to the turbine wheel;

[0017] A centrifugal compressor assembly includes a compressor housing and a compressor impeller mounted in the compressor housing and connected to a rotatable shaft for rotation therewith. The compressor impeller has blades and defines an inlet guide portion. The compressor housing has an air inlet wall defining an air inlet for generally axially guiding air into the compressor impeller. The compressor housing further defines a volute for receiving compressed air generally radially outwardly discharged from the compressor impeller. The compressor housing defines an annular space confined between an upstream wall and a downstream wall spaced axially therefrom. The annular space surrounds the air inlet and opens to the air inlet at a radially inner end of the annular space.

[0018] A compressor inlet regulating mechanism, disposed within the annular space of the air inlet wall and movable between an open and a closed position, comprises a plurality of blades disposed within the annular space, the blades collectively defining an orifice. Each blade has an upstream surface relatively farther from and away from the compressor impeller and a downstream surface relatively closer to and facing the compressor impeller. When the blades are in the closed position, each blade pivots radially inward from the annular space into the air inlet, such that the orifice has a reduced diameter relative to the nominal diameter of the inlet; and

[0019] A coordinating ring surrounding the blade, rotatable about an axis of rotation substantially coaxial with the axis of rotation of the turbocharger, the coordinating ring having a radially inner peripheral surface and a radially outer peripheral surface, the radially outer peripheral surface defining a plurality of circumferentially spaced notches, one notch corresponding to each blade.

[0020] Each of the blades includes an orifice portion at one end of the blade, a connecting arm at the opposite end of the blade, and a mounting portion disposed between the connecting arm and the orifice portion. Each blade is supported by a pivot pin attached to the mounting portion and rotatably engaged in an opening in the compressor housing, such that the blade pivots about an axis defined by the opening. The mounting portion of the blade is radially inwardly disposed from the radial inner periphery of the coordinating ring. The connecting arm of each blade includes a support portion extending radially outwardly from the mounting portion, the support portion passing adjacent to and axially supporting the downstream face of the coordinating ring. Each connecting arm further includes a hook portion extending axially from the radial outer end of the support portion and engaging in a corresponding recess in the radial outer periphery of the coordinating ring.

[0021] Thus, the rotation of the coordinating ring imparts pivoting motion to the blade via the hook portion of the connecting arm engaging in the notch in the radial outer perimeter of the coordinating ring.

[0022] In one embodiment, the support portion of each blade includes a raised recess that contacts the downstream surface of the coordinating ring and spaces the remainder of the support portion from the downstream surface. The recess reduces the amount of surface area of ​​contact between the coordinating ring and the blade, thereby reducing frictional resistance to the rotation of the coordinating ring.

[0023] In one embodiment of the invention, each blade includes an annular centering surface disposed on the mounting portion of the blade, the annular centering surface of the blade contacting the radial inner periphery of the coordinating ring and jointly serving to radially position the coordinating ring such that the rotation axis of the coordinating ring is substantially coaxial with the rotation axis of the turbocharger.

[0024] According to one embodiment, each blade and the pivot pin thereon comprise an integral, one-piece structure.

[0025] According to one embodiment, the main portion of the radial outer perimeter of the coordinating ring is located at a distance of radius from the axis of rotation. RO On the circle, but the radial outer perimeter bulges radially outward in a local area near the notch to a radius. RO + ΔR So that the notch is located at a position greater than RO At the radius of.

[0026] The turbocharger may further include a linear actuator operable to rotate the coordinating ring. The actuator includes an actuator rod, and the compressor housing defines a rod opening extending tangentially to the radial outer perimeter of the coordinating ring. The actuator rod is disposed in the rod opening and is linearly movable therein. The compressor housing defines an opening that advances radially outward into the rod opening at a distal end of the actuator rod, and the coordinating ring defines a protrusion extending radially outward from the radial outer perimeter of the coordinating ring. The protrusion passes through the opening into the rod opening and engages the distal end of the actuator rod, such that linear movement of the actuator rod is transmitted through the protrusion to the coordinating ring, thereby rotating the coordinating ring.

[0027] According to one embodiment of the invention, frictional resistance to the movement of the coordinating ring, blade, and actuator rod of the inlet regulating mechanism is reduced by constructing the blade and its pivot pin in plastic (e.g., by injection molding). Additionally, the actuator rod may comprise a metal rod, but the distal end of the actuator rod may comprise a plastic cap (e.g., formed by overmolding around the metal rod). Thus, the coordinating ring engages the plastic surfaces of the blade and the actuator rod. The coordinating ring is advantageously made of metal, and therefore providing a plastic (low-friction) engagement surface for the coordinating ring results in a reduction in overall frictional resistance to the movement of the mechanism. Attached Figure Description

[0028] Therefore, having already provided a general description of the invention, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and in the drawings:

[0029] Figure 1 This is an end view of a turbocharger according to an embodiment of the present invention, viewed axially from the compressor end toward the turbine end.

[0030] Figure 2 It is the turbocharger along Figure 1 Cross-sectional view of line 2-2 in the diagram;

[0031] Figure 3 yes Figure 1 A partially exploded view of the compressor section of a turbocharger;

[0032] Figure 4 yes Figure 3 An isometric side view of the compressor housing assembly, wherein the compressor cover (inlet pipe component) is disassembled to make the inlet regulating mechanism visible;

[0033] Figure 5 This is an isometric side view of a portion of the inlet adjustment mechanism and therefore the actuator, wherein the inlet adjustment mechanism is in the open position when viewed from the upstream side of the mechanism;

[0034] Figure 6 This is a plan (axial) view of a coordinating ring for an inlet adjustment mechanism according to an embodiment of the present invention;

[0035] Figure 7 This is an isometric side view of the blades of the inlet regulating mechanism, showing the upstream surface of the blades;

[0036] Figure 8 This is an axial view of a compressor housing according to an embodiment of the present invention, wherein the housing is partially disassembled to show details of the housing for the actuator and the rod opening for the actuator rod.

[0037] Figure 9 Is it through Figure 1A cross-sectional view of the compressor housing assembly and inlet regulating mechanism of the turbocharger; and

[0038] Figure 10 This is a partial cross-sectional isometric view of an actuator rod according to an embodiment of the present invention. Detailed Implementation

[0039] The invention will now be described more fully below with reference to the accompanying drawings, which show some, but not all, embodiments of the invention. In fact, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Throughout, similar reference numerals refer to similar elements.

[0040] In this disclosure, the term "orifice" means "opening" without regard to the shape of the opening. Thus, an "orifice" can be circular or non-circular. Furthermore, when the blades of the inlet regulating mechanism are described as pivoting "radially" inward or outward, the term "radial" does not exclude some non-radial movement components of the blades (e.g., the blades may occupy a plane slightly angled relative to the compressor's axis of rotation, such that when the blades pivot radially inward and outward, they also move with small axial movement components; alternatively, the blades may pivot and translate, for example, in a helical motion).

[0041] exist Figure 1 A turbocharger 10 according to an embodiment of the present invention is shown in an axial end view. Figure 2 The image shows an axial cross-sectional view of a turbocharger. The turbocharger includes a compressor and a turbine. The compressor includes a compressor impeller or impeller 14 mounted on one end of a rotating shaft 18 within a compressor housing 16. The compressor housing includes walls defining an air inlet 17 for generally axially guiding air into the compressor impeller 14. The shaft is supported in bearings mounted in a central housing 20 of the turbocharger. The shaft is rotated by a turbine impeller 22 mounted relative to the compressor impeller at the other end of the shaft, thereby rotatably driving the compressor impeller, which compresses air drawn in through the compressor inlet and discharges the compressed air generally radially outward from the compressor impeller into a volute 21 for receiving the compressed air. From the volute 21, air is delivered to the intake section of an internal combustion engine (not shown) to enhance engine performance.

[0042] Turbine wheel 22 is disposed within turbine housing 24, which defines an annular chamber 26 for receiving exhaust gas from an internal combustion engine (not shown). The turbine housing also defines nozzles 28 for guiding the exhaust gas generally radially inward from chamber 26 to turbine wheel 22. The exhaust gas expands as it passes through the turbine wheel and rotatably drives the turbine wheel, which in turn rotatably drives compressor wheel 14, as already described.

[0043] refer to Figure 1-4 In the illustrated embodiment, the wall defining the air inlet 17 is partially formed by the compressor housing 16 and partially by a separate cover or inlet duct member 16d, which is received into a cylindrical housing defined by the compressor housing. The portion of the air inlet 17 adjacent to the compressor impeller 14 defines a generally cylindrical inner surface 17i having a diameter that generally matches the diameter of the inlet guide portion 14i of the compressor impeller.

[0044] The compressor housing 16 defines a shroud surface 16s that is closely adjacent to the radially outer tip of the compressor blades. The shroud surface defines a curved profile that is generally parallel to the profile of the compressor impeller.

[0045] According to the present invention, the compressor of the turbocharger includes an inlet regulating mechanism 100 disposed in an air inlet 17 of the compressor housing. The inlet regulating mechanism includes an annular assembly and is disposed in an annular space defined between the compressor housing 16 and a separate inlet duct member 16d. The annular space is confined between an upstream wall surface 105 and a downstream wall surface 107. Figure 9 The inlet adjustment mechanism is operable to adjust the effective diameter of the air inlet to the compressor impeller. Thus, the inlet adjustment mechanism is movable between an open position and a closed position, and can be configured to be adjusted to various points between said positions.

[0046] Now for reference Figure 3-8 The inlet regulating mechanism includes a plurality of blades 102 arranged about the central axis of the air inlet and each capable of pivoting about a pivot pin 102p located at or near one end of the blade. In the illustrated embodiment, the pivot pin for the blade is journaled in an opening 107b in the downstream wall surface 107 of the compressor housing. Figure 3 and Figure 8 This allows the pivot pin to rotate within the opening. In this embodiment, the pivot pin is integral with the blade and rigidly attached to it. The blade is arranged between the upstream wall surface 105 and the downstream wall surface 107, with a small axial clearance or play between those wall surfaces, allowing the blade to pivot freely without engaging.

[0047] The inlet regulating mechanism further includes a coordinating ring 106 for imparting pivoting motion to the blades. The coordinating ring surrounds the assembly of the blade 102 and is substantially coplanar with the blades, and is rotatable about an axis coinciding with the rotational axis of the compressor impeller. The coordinating ring includes a plurality of recesses 108, and each blade includes an end portion engaging in a corresponding recess 108, as described below. Figure 5-7 and Figure 9 As described in further detail. Therefore, rotation of the coordinating ring in one direction causes the blade 102 to pivot radially inward, and rotation of the coordinating ring in the other direction causes the blade to pivot radially outward. The assembly of blade 102 and coordinating ring 106 is captively held between the upstream wall surface 105 and the downstream wall surface 107.

[0048] The radial inner edge of blade 102 includes a generally arcuate portion, and these edges together surround and define a generally circular opening or aperture (although the roundness varies depending on the position of the blade, as further described below).

[0049] The pivoting range of the blade is sufficient to allow the blade to move in one direction via the coordination ring. Figure 5 Rotation radially outward in the clockwise direction (as shown in the image) to, for example Figure 5 The open position shown is such that the blade is completely radially outside the inner surface 17i of the inlet. Figure 2 Thus, in the open position of the blades, the inlet adjustment mechanism does not change the nominal inlet diameter defined by the inlet surface 17i.

[0050] The blades can also pivot radially inward (via the coordinating ring in the opposite direction), Figure 5 (rotation in the counterclockwise direction) to such Figure 9The closed position is shown. In the closed position, the arcuate edges along the radially inner side of the blade collectively form an orifice. In the illustrated embodiment, the orifice in the closed position is generally circular, having a diameter smaller than the diameter of the inlet surface 17i. (In this disclosure, "generally circular" means that the arcuate edges are all located on the same circle and collectively occupy at least 80% of the circumference of said circle). This results in a reduction in the effective diameter of the inlet relative to the nominal inlet diameter. Furthermore, in an embodiment not shown, the blade can pivot an additional amount to a super-closed position in which adjacent blades overlap to some extent, which is made possible by forming the corresponding overlapping edge portions of adjacent blades into complementary or male-female shapes. When the blade is in the super-closed position, the arcuate edges of the blade collectively define an opening or orifice that is not perfectly circular but is effectively even smaller than the opening in the closed position. Therefore, the inlet adjustment mechanism causes the effective diameter of the inlet to be further reduced relative to the closed position. In this way, the inlet adjustment mechanism can adjust the effective diameter of the air inlet close to the compressor wheel.

[0051] However, it should be noted that it is not necessary for the orifice defined by the inlet adjustment mechanism to be circular in the closed position. Alternatively, the orifice may be non-circular. The invention is not limited to any particular shape of orifice.

[0052] As previously described, blade 102 is actuated by a coordinating ring 106 capable of rotating about the central axis of the air inlet to pivot between its open and closed (and optionally, super-closed) positions. Now refer to Figure 4-5 Rotational motion is imparted to the coordinating ring via actuator 116, which is received by the housing 116a defined within the compressor housing. Figure 3 The actuator includes a rod opening 16rb extending through a portion defined in the compressor housing. Figure 8 The actuator rod 117. The rod opening is tangent to the coordinating ring 106 and passes radially outward from the coordinating ring 106. The compressor housing wall located radially outward from the coordinating ring defines an opening 16o that extends radially outward and connects with the rod opening. The coordinating ring defines a protrusion 109 ( Figure 4 and Figure 6 The protrusion passes through the opening 16o and engages the slot or groove 117g at the distal end of the actuator rod 117. Figure 10 The actuator is operable to extend and retract the lever 117 linearly along its length to rotate the coordinating ring 106 and thereby actuate the blade 102. Extending the lever will cause the blade to pivot toward the closed position, and retracting the lever will cause the blade to pivot toward the open position.

[0053] As described, the inlet adjustment mechanism 100 allows for adjustment of the effective size or diameter of the inlet in the compressor wheel 14. Figure 2As shown, when the inlet regulating mechanism is in the closed position, the effective diameter of the inlet to the compressor impeller is determined by the inner diameter defined by the blade 102. To achieve this effect, the axial distance between the blade and the compressor impeller must be as small as possible, such that when air encounters the compressor impeller 14, the distance downstream of the blade is insufficient to allow the flow to extend to the entire diameter of the inlet guide portion of the compressor impeller 14. Thus, the inlet diameter is effectively reduced to the value determined by the blade.

[0054] At low flow rates (e.g., low engine speeds), the inlet regulating mechanism 100 can be positioned... Figure 2 and Figure 6 In the closed position. This can have the effect of reducing the effective inlet diameter and thus increasing the flow velocity entering the compressor impeller. The result will be a reduced compressor blade incident angle, thereby effectively stabilizing the flow (i.e., reducing the likelihood of blade stall and compressor surge). In other words, the compressor surge line will shift to a lower flow rate (shifting to the left on the compressor pressure versus flow rate graph).

[0055] At intermediate and high flow rates, the inlet regulating mechanism 100 can be as follows: Figure 5 It can be partially or fully opened as in the middle. This can have the effect of increasing the effective inlet diameter, allowing the compressor to restore its high-flow performance and blocked flow, essentially as if the inlet regulating mechanism did not exist and as if the compressor had a conventional inlet with an impeller diameter at the inlet guide section that matches the impeller.

[0056] According to one aspect of the invention disclosed herein, the inlet regulating mechanism 100 includes features for reducing frictional resistance to movement of the inlet regulating mechanism. As previously described, the inlet regulating mechanism is subjected to significant aerodynamic loads, particularly at low flow rates and high compression ratios, corresponding to the operating state where the blades 102 are typically closed. Consequently, the blades experience a significant pressure difference between their upstream and downstream faces, causing the blades to abut against the compressor housing structure directly adjacent to them in the downstream direction. These aerodynamic loads, combined with internal friction within the inlet regulating mechanism, act as a resistive force on the actuator 116 that moves the mechanism between the open and closed positions. This results in a significantly large actuation force required from the actuator, meaning a larger and more expensive actuator is needed to achieve the actuation speed required for proper compressor operation.

[0057] The features of this invention can reduce the frictional resistance of the mechanism and provide mechanical advantages to the linkage between the actuator, coordinating ring, and blade, resulting in the achievement of the desired speed and reliability of mechanism actuation without the need for large and expensive actuators. According to a first aspect of the invention, the actuator-to-blade linkage mechanism is designed to obtain the improved mechanical advantages, as now explained. Figure 6 As best seen in the image, the coordination ring 106 has a radially inner peripheral surface 106i and a radially outer peripheral surface 106o. The radially outer peripheral surface defines a plurality of circumferentially spaced notches 108, one of which is for each of the blades 102. A large portion of the perimeter of the outer peripheral surface is circular, having a [missing information - likely a circumference value]. RO The radius. However, near each notch 108, the outer peripheral surface bulges radially outward (as indicated by reference numeral 106b), and the radius of the bulging portion of the outer peripheral surface is... RO + ΔR ,in ΔR The value is at least as large as the radial depth of the notch 108. Therefore, the notch 108 is located at least as large as the radial depth of the notch 108. RO At the same radius.

[0058] Now for reference Figure 7 Each blade 102 has an orifice portion 102o, which is such that when the blade is closed, the orifice portion 102o, together with the orifice portions of the other two blades, effectively forms an orifice with a reduced diameter. A mounting portion 102m is attached to the orifice portion and supports a pivot pin 102p attached to the mounting portion. The mounting portion 102m of the blade is radially inward from the radial inner periphery of the coordinating ring 106, as... Figure 5 As shown in the diagram. The linkage arm is coupled to the mounting portion of each blade, which includes a support portion 102s extending radially outward from the mounting portion, the support portion passing adjacent to and axially supporting the downstream face of the coordinating ring 106. Figure 9 Each link arm further includes a hook portion 102h, which extends axially from the radially outer end of the support portion 102s and engages in a corresponding recess 108 in the radially outer periphery of the coordinating ring. Figure 5 ).

[0059] Each blade's support portion 102s includes a raised recess 102r, which contacts the downstream surface of the coordinating ring 106. Figure 9 And the remaining portion of the support portion is spaced apart from the downstream surface. Each blade also includes an annular centering surface 102c disposed on the mounting portion 102m of the blade, the annular centering surface of the blade contacting the radial inner perimeter 106i of the coordinating ring 106. Figure 5And together they are used to radially position the coordinating ring, such that the axis of rotation of the coordinating ring is substantially coaxial with the axis of rotation of the turbocharger. The ring centering surface 102c has an arc shape and is configured such that when the blades pivot due to the rotation of the coordinating ring, the portion of the inner periphery of the coordinating ring that contacts the ring centering surface makes rolling contact with the ring centering surface (completely different from relative sliding contact).

[0060] These features help to minimize the actuating force required by actuator 116 to actuate blade 102. Because the hook portion 102h of the blade engages the notch 108 in the outer periphery of the coordinating ring 106, the length of the blade's connecting rod arm can be longer than the length it would have if the blade engaged the inner periphery of the coordinating ring. This means that the actuating force required to pivot the blade against a given drag (caused by friction and exacerbated by high aerodynamic loads) is reduced.

[0061] Furthermore, according to a second aspect of the invention, the frictional resistance to the rotation of the coordinating ring is reduced by features of the invention. More specifically, by providing a support portion 102s of the blade with a raised recess 102r, the surface area of ​​the downstream surface of the coordinating ring subjected to friction (the surface forced to abut against adjacent structures by high aerodynamic loads) is reduced, the raised recess 102r spacing most of the surface of the support portion away from the downstream surface of the coordinating ring. Therefore, the downstream surface of the coordinating ring only contacts the recess 102r, which has a small total surface area in contact with the coordinating ring.

[0062] Furthermore, because the coordinating ring allows for rolling contact with the ring centering surface 102c on the mounting portion of the blade 102, relative sliding and therefore friction are reduced at these locations. It is also worth noting that providing the ring centering surface eliminates the need for separate ring centering guides (e.g., pins or rollers) in the inlet adjustment mechanism.

[0063] To further reduce friction and the actuating force required to pivot the blades, low-friction materials are used in critical locations. Therefore, according to some embodiments of the invention, the blades 102 are constructed of plastic having a lower coefficient of friction than metals typically used for blades. Advantageously, each blade 102 and its associated pivot pin 102p constitute a single-piece integral part, which can be formed, for example, by injection molding, etc. Thus, the pivot pin has a low-friction surface that contacts the inner surface of the opening in the compressor housing through which the pivot pin rotates. The contact points between the blades and adjacent parts (e.g., the upstream wall 105 of the cavity of the coordinating ring 106 and the inlet regulating mechanism) are similarly formed of low-friction plastic.

[0064] In this regard, in some embodiments of the invention, the upstream wall 105 ( Figure 9 It can also be formed from plastic. More specifically, see reference... Figure 3 and Figure 4 , forming an upstream wall 105 ( Figure 9 The inlet pipe component 16d of the compressor housing can be an injection-molded plastic part, which is fastened to the rest of the metal compressor housing 16 by metal bolts. BO The hole has a metal insert MI Another feature of the invention is that a plurality of circumferentially spaced axial spacers 16as are provided on the upstream wall 105 of the inlet pipe member, such as... Figure 9 As shown in the diagram. The axial spacers effectively space the remaining portion of the coordinating ring 106 axially away from the upstream wall, so that the coordinating ring only contacts a few of the axial spacers.

[0065] refer to Figure 10 Plastic is also advantageously used at the interface between the coordinating ring 106 and the actuator rod 117. Thus, the actuator rod advantageously comprises a central rod 117m made of metal, but the distal end portion of the actuator rod includes a plastic cap 117pc. This cap can be formed by injection molding (so-called overmolding) around the end of the metal rod. The end portion of the actuator rod defines a groove 117g for receiving and engaging the protrusion 109 from the coordinating ring 106 (see...). Figure 5 Therefore, the low-friction plastic surface of the contact ring actuator rod is used.

[0066] Another aspect of the invention relates to a method for assembling an inlet regulating mechanism. (See reference...) Figure 3 and Figure 4 Once the blade 102 has been placed into the compressor housing cavity by inserting the pivot pin 102p into the opening 107b in the compressor housing wall 107, the blade 102 is then positioned by tilting the oriented coordination ring (where the side having the protrusion 109 is lower than the opposite side of the ring) and inserting the protrusion 109 through the opening 16o in the compressor housing wall so that the protrusion engages in the groove 117g in the actuator rod. Figure 10 The coordinating ring 106 is then installed, and the remainder of the ring is lowered into place such that the notch 108 in the outer periphery of the ring engages the hook 102h of the blade 102. To facilitate this installation, the end of the hook 102h is preferably chamfered to guide the hook into the notch. The inlet pipe assembly / cover 16d is then placed on the compressor housing 16 and secured with bolts. BO Bolts are connected in the appropriate positions.

[0067] Benefiting from the teachings presented in the foregoing description and associated drawings, those skilled in the art will conceive of numerous modifications and other embodiments of the invention set forth herein. For example, although the illustrated embodiment employs three blades 102, the invention is not limited to any particular number of blades. The invention can be practiced with as few as two blades or as many as twelve or more blades. The number of blades can be chosen as desired. Furthermore, although blades with rounded edges have been shown and described, blades need not have rounded edges. Blades with edges of different shapes (linear, elliptical, etc.) are also included within the scope of the invention. Therefore, it should be understood that the invention is not limited to the specific embodiments disclosed, and many modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terminology is used herein, it is used only in a general and descriptive sense and not for limiting purposes.

Claims

1. A turbocharger, comprising: A turbine housing and a turbine wheel mounted in the turbine housing and connected to a rotatable shaft to rotate therewith, the turbine housing receiving exhaust gas and supplying the exhaust gas to the turbine wheel; A centrifugal compressor assembly includes a compressor housing and a compressor impeller mounted in the compressor housing and connected to a rotatable shaft for rotation therewith. The compressor impeller has blades and defines an inlet guide portion. The compressor housing has an air inlet wall defining an air inlet for guiding air substantially axially into the compressor impeller. The compressor housing further defines a volute for receiving compressed air discharged substantially radially outward from the compressor impeller. The compressor housing defines an annular space confined between an upstream wall and a downstream wall spaced axially therefrom. The annular space surrounds the air inlet and opens to the air inlet at a radially inner end of the annular space. as well as A compressor inlet adjusting mechanism is disposed in the annular space of the compressor housing and is movable between an open position and a closed position. The inlet adjusting mechanism includes a plurality of blades disposed in the annular space, wherein each of the blades includes an orifice portion at one end of the blade, a connecting arm at the opposite end of the blade, and a mounting portion disposed between the connecting arm and the orifice portion. The orifice portions of the blades collectively define an orifice. When the blade is in the closed position, the blade pivots radially inward from the annular space into the air inlet so that the orifice has a reduced diameter relative to the nominal diameter of the inlet. as well as A coordinating ring surrounding the blade, rotatable about an axis of rotation substantially coaxial with the axis of rotation of the turbocharger, the coordinating ring having a radially inner peripheral surface and a radially outer peripheral surface, the radially outer peripheral surface defining a plurality of circumferentially spaced notches, one notch corresponding to each blade. Each blade is supported by a pivot pin attached to the mounting portion and rotatably engaged in an opening in the compressor housing, such that the blade pivots about an axis defined by the opening. The mounting portion of the blade is radially inwardly disposed from the radial inner periphery of the coordinating ring. Each blade's linkage arm includes a support portion extending radially outwardly from the mounting portion, the support portion passing adjacent to and axially supporting the downstream face of the coordinating ring. Each linkage arm further includes a hook portion extending axially from the radial outer end of the support portion and engaging in a corresponding notch in the radial outer periphery of the coordinating ring. Thus, the rotation of the coordinating ring imparts pivoting motion to the blade via the hook portion of the connecting arm engaging in the notch in the radial outer perimeter of the coordinating ring.

2. The turbocharger according to claim 1, wherein, Each blade's support portion includes a raised recess that contacts the downstream surface of the coordinating ring and spaces the remainder of the support portion from the downstream surface.

3. The turbocharger according to claim 1, wherein, Each blade includes an annular centering surface disposed on the mounting portion of the blade, the annular centering surface of the blade contacting the radial inner periphery of the coordinating ring and jointly serving to radially position the coordinating ring such that the axis of rotation of the coordinating ring is substantially coaxial with the axis of rotation of the turbocharger.

4. The turbocharger according to claim 3, wherein, The ring centering surface is arc-shaped and configured such that when the coordinating ring rotates and the blade pivots, the radial inner perimeter of the coordinating ring makes rolling contact with the ring centering surface.

5. The turbocharger according to claim 1, wherein, Each blade and the pivot pin used for it comprise an integral, one-piece structure.

6. The turbocharger according to claim 1, wherein, The main portion of the radial outer perimeter of the coordinating ring lies on a circle with a radius RO from the axis of rotation, but the radial outer perimeter bulges radially outward in a local area near the notch to a radius RO. RO + ΔR, This ensures that the notch is located at a radius greater than RO.

7. The turbocharger of claim 1, further comprising a linear actuator operable to rotate the coordinating ring, the linear actuator including an actuator rod, the compressor housing defining a rod opening extending along a direction tangential to the radial outer periphery of the coordinating ring, the actuator rod disposed in the rod opening and linearly movable therein, the compressor housing defining an opening radially outwardly advancing into the rod opening at a distal end of the actuator rod, the coordinating ring defining a protrusion extending radially outwardly from the radial outer periphery of the coordinating ring, the protrusion passing through the opening into the rod opening and engaging the distal end of the actuator rod such that linear movement of the actuator rod is transmitted through the protrusion to the coordinating ring, thereby rotating the coordinating ring.

8. The turbocharger according to claim 7, wherein, The blades are made of plastic.

9. The turbocharger according to claim 8, wherein, Each blade and the pivot pin used for it consist of a single, integral plastic part.

10. The turbocharger of claim 8, wherein the actuator rod comprises a metal rod, and the distal end of the actuator rod includes a plastic cap attached to and enclosing the end of the metal rod, wherein, The protrusion of the coordinating ring engages with the plastic cap.

11. The turbocharger according to claim 1, wherein, The compressor housing includes an inlet pipe member that forms part of the air inlet wall and the upstream wall in the annular space. The inlet pipe member is formed separately from the rest of the compressor housing and is received into a housing in the rest of the compressor housing and attached to the housing by fasteners.

12. The turbocharger according to claim 11, wherein, The inlet pipe component is made of plastic, and the rest of the compressor housing is made of metal.

13. The turbocharger according to claim 12, wherein, The inlet pipe component defines a plurality of circumferentially spaced axial spacers on the upstream wall for engaging the upstream face of the coordinating ring and spaced the coordinating ring away from the remainder of the upstream wall.

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