JP6028715B2 - Compressor housing - Google Patents

Description

  The present invention relates to a compressor housing for a turbocharger provided with an air bypass device that connects an intake upstream side and an intake downstream side of a compressor impeller.

  Conventionally, it has been proposed to provide an air bypass device for returning a part of the intake air from the intake upstream side of the compressor impeller to the intake downstream side of the compressor housing of the turbocharger (see Patent Document 1). The air bypass device includes a bypass passage that communicates an intake upstream portion and an intake downstream portion of the compressor impeller inside the compressor housing. The bypass passage is provided with a bypass valve for changing the passage sectional area of the passage.

JP 2012-241560 A

  Here, high pressure (so-called supercharging pressure) generated by intake air compression by the compressor acts on the valve body of the bypass valve. Therefore, in a turbocharger provided with an air bypass device, it is desirable to firmly fix the bypass valve to the compressor housing in order to avoid intake leakage from the attachment portion of the bypass valve.

  In the turbocharger described in Patent Document 1, the bypass valve is fixed to the compressor housing through bolt fastening at three fixing portions on the periphery thereof. By adopting such a fixing structure, the bypass valve can be firmly fixed to the compressor housing.

  However, in the turbocharger, since the bypass passage is extended in such a manner that it passes between two of the three fixing portions, the passage shape of the bypass passage is limited depending on the formation position of these fixing portions. Therefore, in some cases, it becomes impossible to sufficiently increase the cross-sectional area of the bypass passage, which is a factor that limits the performance improvement of the air bypass device.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a compressor housing capable of efficiently increasing the cross-sectional area of the bypass passage of the air bypass device within a limited space. is there.

  A compressor housing for achieving the above object includes an impeller chamber that is formed in an intake passage through which intake air passes and in which a compressor impeller is disposed, an intake upstream side and an intake downstream side of the impeller chamber in the intake passage And three or more fixing parts to which a screw member for attaching a bypass valve for changing the passage sectional area of the bypass passage is fastened and fixed. Two of the three or more fixing portions are disposed at a position sandwiching the bypass passage. And an angle (specific angle) formed by a line segment that connects the center of gravity of the polygon having the three or more fixed portions as apexes and the two fixed portions arranged at positions sandwiching the bypass passage, It is larger than an angle (another angle) formed by a line segment that connects two fixed portions that are arranged at positions that do not sandwich the bypass passage and that are adjacent vertices of the polygon and the center of gravity. .

  According to the compressor housing described above, the interval between the two fixing portions disposed at the positions sandwiching the bypass passage is set to the two fixing portions which are disposed at positions not sandwiching the bypass passage and become adjacent apexes of the polygon. It can be made larger than the interval. Therefore, compared to the case where the specific angle is equal to the other angle or the specific angle is smaller than the other angle, the range in which the bypass passage can be formed in a limited space sandwiched between the two fixing portions. The cross-sectional area of the bypass passage can be increased efficiently.

In the compressor housing, two fixing portions disposed at positions sandwiching the bypass passage may be disposed at positions on both sides of the bypass passage.
In the compressor housing, the screw member is fastened and fixed in the direction of the rotation axis of the compressor impeller, and the portion of the intake air flow upstream of the impeller chamber starts from the impeller chamber. The inlet passage may extend in the direction of the rotation axis. Further, the inlet passage can be communicated with an intake passage of the engine, and the intake passage can be formed in a shape extending in a curved portion adjacent to the connection portion with the inlet passage.

  In the compressor housing, the width of the bypass passage (the length of the passage section between the two fixed portions) is increased, or the height of the bypass passage (the length of the passage section in the direction perpendicular to the straight line connecting the two fixed portions). ) Is increased, the passage cross-sectional area of the bypass passage can be increased. However, the compressor housing has a structure in which the width of the bypass passage is limited by the formation position of the two fixing portions. In the compressor housing, the screw member and the inlet passage extend in the direction of the rotation axis of the compressor impeller, and the bypass passage communicates with the inlet passage through the two fixed portions. Is increased, the passage cross section of the bypass passage becomes longer in the rotational axis direction. Therefore, when the height of the bypass passage is increased in order to increase the passage sectional area of the bypass passage, the portion to which the bypass passage is connected, that is, the inlet passage extending in the rotation axis direction becomes longer in the rotation axis direction, and the compressor housing As a result, the size of the compressor may be increased.

  According to the compressor housing, since the width of the bypass passage can be increased when determining the shape of the bypass passage, the passage cross-sectional area of the bypass passage is suppressed while suppressing an increase in the height of the bypass passage. Can be set to an appropriate size. Therefore, it is possible to prevent the inlet passage of the intake flow passage from becoming longer in the direction of the rotation axis, thereby reducing the size of the compressor.

  In addition, according to the compressor housing, since the inlet passage is suppressed from being elongated in the rotational axis direction, a space for curving the intake passage of the engine connected to the inlet passage is suppressed from being reduced. It is possible to suppress the bending radius of the intake passage from becoming unnecessarily small. Here, when the bending radius of the intake passage is reduced, the pressure loss in the intake passage is increased. According to the compressor housing, since the bending radius of the specific intake passage can be suppressed, an increase in pressure loss in the intake passage can be suppressed.

1 is a side view of a turbocharger having an embodiment of a compressor housing. FIG. Sectional drawing of the turbocharger. The side view of the compressor housing which attached the compressor impeller. Schematic diagram showing the internal structure of the compressor. Sectional drawing which expands and shows the part which two fixing | fixed parts of a compressor housing pinch | interposed the 2nd channel | path. The side view which expands and shows the opening of the 1st channel | path in a compressor housing, and its periphery. The side view which shows the connection part of an inlet passage and an intake passage, and its periphery.

Hereinafter, an embodiment of the compressor housing will be described.
As shown in FIG. 1 or FIG. 2, the turbocharger 10 includes an exhaust turbine 11, a compressor 12, and a center housing 13 that connects the exhaust turbine 11 and the compressor 12. A compressor impeller 14 is disposed inside the compressor 12. The compressor impeller 14 is coupled to a turbine wheel (not shown) in the exhaust turbine 11 so as to be integrally rotatable. The turbocharger 10 is integrally attached with an actuator 15 for operating a waste gate valve (not shown).

  The compressor 12 includes a compressor housing 20, and an intake passage 21 through which intake air passes is formed inside the compressor housing 20. The intake passage 21 includes an inlet passage 22, an impeller chamber 23, a diffuser 24, and a scroll passage 25 in order from the intake upstream side. The inlet passage 22 is formed in a shape extending in the direction of the rotation axis L of the compressor impeller 14 from the inlet portion 22A of the compressor housing 20 to the impeller chamber 23 in which the compressor impeller 14 is disposed. Through this inlet passage 22, intake air is introduced into the compressor housing 20 and guided to the impeller chamber 23. The scroll passage 25 is formed in a shape extending spirally around the outer periphery of the impeller chamber 23. The diffuser 24 is formed in a shape that allows the impeller chamber 23 and the scroll passage 25 to communicate with each other over the entire outer periphery of the impeller chamber 23.

  In such a turbocharger 10, supercharging is performed as follows. When the compressor impeller 14 is rotated by the energy of the engine exhaust, the intake air flowing from the inlet portion 22A of the compressor 12 is sent to the diffuser 24 by the action of centrifugal force due to the rotation of the compressor impeller 14. The intake air is converted into a high-pressure / low-speed flow in the diffuser 24 and then sent to the engine through the scroll passage 25.

The compressor 12 is provided with an air bypass device 30 for returning a part of the intake air from the intake upstream side of the compressor impeller 14 to the intake downstream side.
Specifically, the compressor housing 20 is provided with a first passage 31 that communicates the inside and the outside of the scroll passage 25. The first passage 31 extends in a circular cross section parallel to the rotation axis L of the compressor impeller 14. The first passage 31 is located at an intermediate portion in the extending direction (vertical direction in FIG. 3) of a portion (small diameter portion 31A) close to the scroll passage 25 whose inner diameter is far from the scroll passage 25 (large diameter portion 31B). A step portion 31C having a shape smaller than the inner diameter is formed. The compressor housing 20 is formed with a second passage 32 that communicates the large-diameter portion 31 </ b> B of the first passage 31 with the inlet passage 22. The second passage 32 extends in a substantially quadrangular cross section in a direction orthogonal to the rotation axis L of the compressor impeller 14.

  In the present embodiment, the first passage 31 and the second passage 32 function as a bypass passage 33 that communicates the intake upstream side and the intake downstream side of the impeller chamber 23 in the intake passage 21. The first passage 31 corresponds to a portion connected to the intake downstream side of the impeller chamber 23 in the intake passage 21. Further, the second passage 32 corresponds to a portion connected to the intake upstream side of the impeller chamber 23 in the intake passage 21.

Further, a bypass valve 34 that opens and closes the bypass passage 33 is attached to the compressor housing 20.
FIG. 3 shows a side structure of the compressor housing 20 with the compressor impeller 14 attached. As shown in FIG. 3, an internal thread extending in parallel with the rotation axis L direction of the compressor impeller 14 (vertical direction in the drawing of FIG. 3) is fixed to the periphery of the opening of the first passage 31 on the outer wall of the scroll passage 25. It is formed as. In the present embodiment, three fixing portions 35 are provided at positions that surround the periphery of the opening of the first passage 31 on the outer wall of the scroll passage 25.

  Then, as shown in FIG. 1 or FIG. 2, the bolt 36 as a screw member is fastened and fixed to the fixing portion 35 with the attachment portion 34 </ b> A of the bypass valve 34 sandwiched therebetween, whereby the bypass valve is attached to the compressor housing 20. 34 is attached. In the compressor housing 20, the first passage 31 of the bypass passage 33 extends to a portion surrounded by the three fixing portions 35, and the second passage 32 of the bypass passage 33 passes between the two fixing portions 35. It is extended by.

  One end (the valve body 34 </ b> B) of the bypass valve 34 is inserted into the first passage 31 of the bypass passage 33. The bypass valve 34 employs an electromagnetic drive type, and the valve body 34B is reciprocated in the direction of the rotation axis L (the vertical direction in FIG. 2). A valve seat 34 </ b> C is formed in the step portion 31 </ b> C of the first passage 31 of the bypass passage 33. When the valve body 34B of the bypass valve 34 moves toward the scroll passage 25 and is seated on the valve seat 34C, the small-diameter portion 31A of the first passage 31 is closed (closed state) by the valve body 34B. Communication between the scroll passage 25 and the inlet passage 22 through the bypass passage 33 is blocked. On the other hand, when the valve body 34B of the bypass valve 34 moves away from the scroll passage 25 and leaves the valve seat 34C, the small diameter portion 31A of the first passage 31 is opened to the second passage 32 (valve open state). Thus, the inlet passage 22 and the scroll passage 25 are communicated with each other through the bypass passage 33.

  FIG. 4 shows the internal structure of the compressor 12. As shown in FIG. 4, in an engine provided with a turbocharger, for example, when the depression of the accelerator pedal is released in a situation where the amount of intake air is large, the intake air in the downstream portion of the compressor 12 (the scroll passage 25) There is a possibility that the pressure becomes very high as compared with the intake pressure of the intake upstream portion (inlet passage 22). In this case, a phenomenon (a so-called surging phenomenon) occurs in which a part of the intake air flows backward (flow indicated by a black arrow in FIG. 4) from the scroll passage 25 to the inlet passage 22 via the impeller chamber 23. There is a fear. When a surging phenomenon occurs, this generates noise or increases the pulsation of the intake pressure and decreases the accuracy of engine control. In the present embodiment, the bypass valve 34 is driven to open when the engine operating state is expected to generate such a surging phenomenon. As a result, as shown by a white arrow in FIG. 4, a part of the intake air is returned from the scroll passage 25 to the inlet passage 22 through the bypass passage 33, so that the occurrence of the surging phenomenon is suppressed.

  As shown in FIG. 5, in the compressor housing 20, two of the three fixed portions 35 are formed at positions on both sides of the bypass passage 33 and sandwiching the bypass passage 33 therebetween. . Thereby, the 2nd channel | path 32 of the bypass channel | path 33 is extended in the aspect which passes between two of the three fixing | fixed parts 35. As shown in FIG. In the compressor housing 20, the passage shape of the second passage 32 is limited by the formation position of the two fixing portions 35 formed at the positions sandwiching the second passage 32. For this reason, in some cases, the passage cross-sectional area of the second passage 32 cannot be made sufficiently large, which is a factor that limits the performance improvement of the air bypass device 30.

In view of this situation, in the present embodiment, in order to increase the degree of freedom in setting the passage shape of the second passage 32, the three fixing portions 35 are arranged as follows.
FIG. 6 shows an enlarged view of the periphery of the opening of the first passage 31 in the compressor housing 20.

  As shown in FIG. 6, the center of gravity of a triangle whose apexes are three fixing portions 35 (specifically, the center of the screw hole) is referred to as “center of gravity C”. In addition, an angle formed by a line segment connecting the two fixing portions 35 sandwiching the second passage 32 of the bypass passage 33 and the center of gravity C of the triangle is defined as a “specific angle AT”, and the second passage 32 is interposed between the two passages 32. An angle formed by a line segment that connects the two fixed portions 35 not sandwiched between and the center of gravity C is referred to as “another angle AO”. In the present embodiment, the specific angle AT (130 degrees in the present embodiment) is larger than the other angles AO (115 degrees).

The center of the passage section of the first passage 31 extending above Symbol centroid C and a circular cross section triangular match. Therefore, in the compressor housing 20, the specific angle AT is a line segment that separately connects the two fixing portions 35 sandwiching the second passage 32 of the bypass passage 33 and the center of the passage section of the first passage 31. It is the same as the angle formed by Further, the other angle AO is the same as the angle formed by the line segment connecting the two fixing portions 35 that do not sandwich the second passage 32 and the center of the passage section of the first passage 31 separately. .

Hereinafter, the operation of the three fixing portions 35 will be described.
In the compressor housing 20, the specific angle AT is larger than the other angles AO. Therefore, the interval between the two fixing portions 35 (the specific interval WT) sandwiching the second passage 32 is between the second passage 32. It is wider than the interval (the other interval WO) between the two fixed portions 35 not sandwiched between the two. Therefore, the specific interval WT can be widened as compared with the case where the specific angle AT is equal to the other angle AO or the specific angle AT is smaller than the other angle AO. The range in which the passage 32 can be formed can be widened. Therefore, although the second passage 32 of the bypass passage 33 is formed in a limited space around the bypass valve 34 between the two fixing portions 35, the second passage 32 in the space is formed. The cross-sectional area of the passage can be increased efficiently. Thereby, the performance of the air bypass device 30 can be improved and the occurrence of the surging phenomenon can be suitably suppressed.

  Here, in the compressor housing 20, the length of the second passage 32 (width W1 in FIG. 5) between the two fixed portions 35 is increased, or the rotation direction L of the compressor impeller 14 (vertical direction in FIG. 5). ) To increase the length (the height W2 in FIG. 5) of the second passage 32, the passage sectional area of the second passage 32 can be increased. However, the compressor housing 20 has a structure in which the width W1 of the second passage 32 is limited by the positions where the two fixing portions 35 are formed. Further, when the height W2 of the second passage 32 is increased in order to increase the passage cross-sectional area of the second passage 32, as shown by a two-dot chain line in FIG. That is, the inlet passage 22 of the intake passage 21 may be elongated in the direction of the rotation axis L, leading to an increase in size of the compressor housing 20 and thus the compressor 12.

  In the compressor housing 20, since the width W1 of the second passage 32 between the two fixing portions 35 can be increased when the passage shape of the second passage 32 is determined, the second passage in the direction of the rotation axis L is possible. The passage cross-sectional area of the second passage 32 can be set to an appropriate size while suppressing the height W2 of 32 from becoming large. Therefore, it is possible to prevent the inlet passage 22 where one end of the second passage 32 is opened from becoming longer in the direction of the rotation axis L, and the compressor housing 20 and thus the compressor 12 can be downsized.

  FIG. 7 shows a connection portion between the inlet passage 22 of the intake passage 21 and the intake passage 16 of the engine. In FIG. 7, the solid line indicates the connection portion of the turbocharger 10 of the present embodiment, and the two-dot chain line indicates the connection portion of the turbocharger of the comparative example in which the inlet passage 22 is elongated in the direction of the rotation axis L. .

  As shown in FIG. 7, an engine intake passage 16 is connected to the inlet passage 22 of the compressor 12. The intake passage 16 is curved and extends at a portion adjacent to the connection portion with the inlet passage 22.

  In the turbocharger 10 (solid line in the figure) of the present embodiment, the inlet passage 22 is prevented from being elongated in the direction of the rotation axis L. Therefore, it is possible to prevent the space for bending the intake passage 16 from being reduced as in the turbocharger of the comparative example (two-dot chain line in the drawing), and the bending radius of the intake passage 16 is unnecessarily reduced. That can be suppressed. Here, when the bending radius of the intake passage 16 is reduced, the pressure loss in the intake passage 16 is increased. In the turbocharger 10, since the bending radius of the intake passage 16 is suppressed to be smaller than that of the turbocharger of the comparative example, an increase in pressure loss in the intake passage 16 can be suppressed.

As described above, according to the present embodiment, the following effects can be obtained.
(1) A specific angle AT formed by a line segment connecting the center of gravity C of the triangle having the three fixing portions 35 as apexes and the two fixing portions 35 sandwiching the second passage 32 therebetween is defined as The angle was made larger than the other angle AO formed by the line segment connecting the two fixed portions 35 that do not sandwich the two passages 32 therebetween. Therefore, the passage cross-sectional area of the second passage 32 can be efficiently increased in a limited space sandwiched between the two fixing portions 35.

  (2) The fixing portion 35 to which the bolt 36 is fastened and fixed and the inlet passage 22 of the intake passage 21 are formed to extend in the direction of the rotation axis L of the compressor impeller 14. In such a compressor housing 20, it is possible to prevent the inlet passage 22 in which one end of the second passage 32 is opened from being elongated in the direction of the rotation axis L, and the compressor housing 20 and, in turn, the compressor 12 can be reduced in size. In addition, the intake passage 16 of the engine communicated with the inlet passage 22 has a shape extending in a curved manner at a portion adjacent to the connection portion with the inlet passage. In such a compressor housing 20, it is possible to suppress a decrease in the bending radius of the intake passage 16, and thus it is possible to suppress an increase in pressure loss in the intake passage 16.

The above embodiment may be modified as follows.
Su in a manner surrounding the opening of the first passage 31 in the outer wall of the crawl path 25, it is possible to form three fixing portions at an arbitrary position.

  The extending direction of the fixing portion 35 is not limited to the same direction as the rotation axis L direction of the compressor impeller 14 and may be a direction slightly deviated from the rotation axis L direction of the compressor impeller 14. In short, the bolt 36 may be fastened and fixed in the direction of the rotation axis L of the compressor impeller 14. Even with such a compressor housing, the same effects as those described in the above embodiment can be obtained.

  -The extending direction of the fixing | fixed part 35 can be made into arbitrary directions. Further, the extending direction of the second passage 32 is not limited to the direction orthogonal to the rotation axis L, but is changed to any direction such as a direction intersecting the rotation axis L at an arbitrary angle or a direction not intersecting the rotation axis L. can do. In short, any structure may be used as long as the second passage 32 of the bypass passage 33 is sandwiched between the two fixing portions.

  The first passage 31 of the bypass passage 33 is not limited to be extended in a circular cross section, but is extended in an arbitrary cross sectional shape such as an elliptical cross section or a polygonal cross section (for example, a square cross section or a rectangular cross section). can do. When the cross-sectional shape of the first passage is a shape having a center (for example, a cross-sectional elliptical shape, a rectangular cross-sectional shape, or a regular polygonal cross-sectional shape), The cross-sectional center of one passage may coincide.

  -Instead of forming a female screw as the fixing portion 35, a through hole may be formed. In this case, the bolt 36 may be fastened and fixed to the fixing portion by screwing a nut into the bolt 36 inserted through the through hole.

It is not necessary to extend the first passage 31 of the bypass passage 33 in parallel with the rotation axis L of the compressor impeller 14, and the extending direction can be arbitrarily changed.
The compressor housing 20 according to the above embodiment can be applied to a compressor housing provided with four or more fixing portions after the structure is appropriately changed. In this case, the angle defined by the line segment connecting the center of gravity of the polygon (N-square) with all (N) fixed portions as apexes and the two fixed portions sandwiching the second passage 32 between them is specified. Angle AT1 ”. Further, the two fixed portions that do not sandwich the center of gravity and the second passage 32 and the two fixed portions that are adjacent vertices of the polygon (two adjacent portions in the circumferential direction of the opening of the first passage 31). The angle formed by the line segment connecting the fixed part) to each other is referred to as “another angle AO1”. In such a case, the specific angle AT1 may be made larger than all of the other ([N−1]) other angles AO1. In such a compressor housing, the specific angle AT1 is larger than all other angles AO1, and therefore, the interval between the two fixing portions (the specific interval WT1) sandwiching the second passage 32 is interposed between the second passages 32. It is possible to make the interval larger than the interval between the two fixed portions (the other interval WO1) that is the interval between the two fixed portions that are not present and that is the adjacent vertex of the polygon. Therefore, the effect according to the above embodiment can be obtained.

  In the compressor housing provided with four or more fixing portions, each fixing portion can be arranged as follows. The angle formed by the line segment connecting the center of the passage section of the first passage 31 (specifically, the section in the direction orthogonal to the extending direction) and the two fixed portions sandwiching the second passage 32 therebetween is expressed as “ Specific angle AT2 ”. In addition, two fixing portions that are not sandwiched between the center of the passage section of the first passage 31 and the second passage 32 and are adjacent apexes of the polygon (around the opening of the first passage 31) An angle formed by a line segment connecting two fixed portions adjacent to each other in the direction is referred to as “another angle AO2.” In such a case, the specific angle AT2 is set larger than all of the other ([N−1]) other angles AO2. Even with such a compressor housing, the specific angle AT2 is larger than all the other angles AO2, and therefore, the interval between the two fixing portions (specific interval WT2) sandwiching the second passage 32 therebetween is sandwiched between the second passages 32. It can be made wider than the interval between the two fixed portions that are not adjacent to each other and are adjacent to the apex of the polygon (the other interval WO2).

  A bypass valve that changes the cross-sectional area of the bypass passage 33 is attached, such as a bypass valve that can be arbitrarily changed in opening degree, as well as the compressor housing 20 to which the bypass valve 34 that opens and closes the bypass passage 33 is attached. The compressor housing 20 of the above embodiment is applicable to any compressor housing that can be used.

  DESCRIPTION OF SYMBOLS 10 ... Turbocharger, 11 ... Exhaust turbine, 12 ... Compressor, 13 ... Center housing, 14 ... Compressor impeller, 15 ... Actuator, 16 ... Intake passage, 20 ... Compressor housing, 21 ... Intake passage, 22 ... Inlet passage, 22A DESCRIPTION OF SYMBOLS ... Entrance part, 23 ... Impeller chamber, 24 ... Diffuser, 25 ... Scroll passage, 30 ... Air bypass device, 31 ... First passage, 31A ... Small diameter part, 31B ... Large diameter part, 31C ... Step part, 32 ... Second Passage, 33 ... Bypass passage, 34 ... Bypass valve, 34A ... Mounting portion, 34B ... Valve body, 34C ... Valve seat, 35 ... Fixing portion, 36 ... Bolt.

Claims (3)

An impeller chamber formed in an intake passage through which intake air passes and a compressor impeller is disposed; a bypass passage communicating the intake upstream side and the intake downstream side of the impeller chamber in the intake passage; and the bypass passage A compressor housing comprising three or more fixing parts to which a screw member for attaching a bypass valve for changing a passage cross-sectional area of the first and second fixing parts is fastened and fixed;
Of the three or more fixing parts, two fixing parts are arranged at positions sandwiching the bypass passage,
The angle formed by a line segment connecting the center of gravity of the polygon having the three or more fixed portions as apexes and the two fixed portions arranged at positions sandwiching the bypass passage does not sandwich the bypass passage. A compressor housing characterized in that it is larger than an angle formed by a line segment that connects the two fixed portions that are arranged at positions and are adjacent apexes of the polygon and the gravity center. The compressor housing according to claim 1,
The compressor housing according to claim 2, wherein the two fixing portions disposed at positions sandwiching the bypass passage are disposed at positions on both sides of the bypass passage. The compressor housing according to claim 1 or 2,
The screw member is fastened and fixed in the rotation axis direction of the compressor impeller,
The intake flow path is an inlet passage extending in the direction of the rotation axis of the compressor impeller, starting from the impeller chamber, at a portion of the intake air upstream of the impeller chamber.
The inlet passage is in communication with the intake passage of the engine;
A compressor housing characterized in that the intake passage is curved and extends at a portion adjacent to a connection portion with the inlet passage.