turbocharger

Abstract

The turbocharger includes a turbine impeller and a partition wall that divides the interior of the connecting pipe into a first passage and a second passage. When observing a section orthogonal to the axis of rotation of the turbine impeller, the line segment connecting the center of rotation of the turbine impeller to the downstream end of the inner wall in the direction of exhaust flow is the first line segment. A straight line orthogonal to the first line segment and extending from the downstream end along the direction of exhaust flow is the first imaginary line. A straight line passing through the base of the partition wall and orthogonal to the direction of exhaust flow is the second imaginary line. The top of the partition wall lies between the first and second imaginary lines.

Description

Technical Field

[0001] This disclosure relates to turbochargers. Background Technology

[0002] Japanese Patent Application Publication No. 2021-134719 discloses a turbine housing for a turbocharger. The turbine housing includes a turbine vortex chamber. Summary of the Invention

[0003] The problem that the invention aims to solve

[0004] Within the turbine housing, exhaust gas is required to flow smoothly within the turbine vortex chamber.

[0005] Technical solutions for solving the problem

[0006] One aspect of this disclosure relates to a turbocharger for an internal combustion engine, wherein the internal combustion engine includes: a first cylinder and a second cylinder whose combustion stroke is different from that of the first cylinder; and a first exhaust port connected to the first cylinder and a second exhaust port connected to the second cylinder. The turbocharger includes: a turbine impeller; a turbine housing housing the turbine impeller; and a connecting pipe connecting the turbine housing to the internal combustion engine. The connecting pipe has: a contact surface in contact with the internal combustion engine; a first passage communicating with the first exhaust port; a second passage communicating with the second exhaust port; and a partition wall extending from the contact surface, dividing the interior of the connecting pipe into the first passage and the second passage. The turbine housing has a vortex passage extending circumferentially along the turbine impeller between the inner wall of the turbine housing and the outer peripheral surface of the turbine impeller. The vortex passage connects the first passage and the second passage, allowing the exhaust gas passing through the first passage and the exhaust gas passing through the second passage to merge. The cross-section of the vortex passage with the largest flow path cross-sectional area, orthogonal to the rotation axis of the turbine impeller, is a defined cross-section. When observing this defined cross-section, the line segment connecting the rotation center of the turbine impeller to the downstream end of the inner wall in the direction of exhaust gas flow within the vortex passage is the first line segment. A straight line orthogonal to the first line segment and extending from the downstream end along the direction of exhaust gas flow in the vortex passage is the first imaginary line. The partition wall has an end near the contact surface (i.e., a base end) and a top end opposite to the base end. A straight line extending through the base end in a direction orthogonal to the direction of exhaust gas flow from the internal combustion engine to the connecting pipe is the second imaginary line. The top end of the partition wall is located inside the connecting pipe between the first and second imaginary lines. Attached Figure Description

[0007] Figure 1This is a schematic diagram showing the intake and exhaust system of an internal combustion engine that includes a turbocharger according to one embodiment.

[0008] Figure 2 yes Figure 1 Side view of the turbocharger.

[0009] Figure 3 It is along Figure 2 A sectional view along line 3-3.

[0010] Figure 4 It is Figure 3 An enlarged cross-sectional view of the area near the connecting pipe of the supercharger.

[0011] Figure 5 It is Figure 3 An enlarged cross-sectional view of the area near the connecting pipe of the supercharger.

[0012] Figure 6 It is along Figure 4 A sectional view along line 6-6.

[0013] Figure 7 This is an enlarged cross-sectional view of the area near the connecting pipe when the partition wall of the turbocharger is formed to be long.

[0014] Figure 8 This is an enlarged cross-sectional view of the area near the connecting pipe when the partition wall of the turbocharger is made short. Detailed Implementation

[0015] Hereinafter, one embodiment of the booster 10 will be described.

[0016] <Internal Combustion Engine 30>

[0017] like Figure 1 As shown, the internal combustion engine 30 has an intake manifold 33, four cylinders C1, C2, C3, C4, a first exhaust port 31, and a second exhaust port 32.

[0018] The intake manifold 33 has four branch flow paths on its downstream side, each of which is connected to cylinders C1 to C4. A throttle valve 34 is located upstream of the four branch flow paths in the intake manifold 33.

[0019] Cylinders C1, C2, C3, and C4 are arranged in this order. For each cylinder C1 to C4, the intake stroke, compression stroke, combustion stroke, and exhaust stroke occur in this order. When cylinder C1 is in the intake stroke, cylinders C2, C3, and C4 are in the compression stroke, exhaust stroke, and combustion stroke, respectively. When cylinder C1 is in the compression stroke, cylinders C2, C3, and C4 are in the combustion stroke, intake stroke, and exhaust stroke, respectively. When cylinder C1 is in the combustion stroke, cylinders C2, C3, and C4 are in the exhaust stroke, compression stroke, and intake stroke, respectively. When cylinder C1 is in the exhaust stroke, cylinders C2, C3, and C4 are in the intake stroke, combustion stroke, and compression stroke, respectively.

[0020] Cylinders C1 and C4 are the first cylinders connected to the first exhaust port 31. Cylinders C2 and C3 are the second cylinders connected to the second exhaust port 32. As described above, the combustion strokes of the first and second cylinders occur at different times. Sometimes cylinders C1 and C4 are referred to as cylinder N1 and cylinder N3, respectively. Sometimes cylinders C2 and C3 are referred to as cylinder N4 and cylinder N2, respectively. The combustion stroke occurs in the order of cylinders C1, C3, C4, and C2. That is, the combustion stroke occurs in the order of cylinders N1, N2, N3, and N4.

[0021] <Intake and Exhaust System of Internal Combustion Engine 30>

[0022] Reference Figure 1 and Figure 2 A general description of the intake and exhaust system of the internal combustion engine 30 is given.

[0023] like Figure 1 As shown, the intake and exhaust system of the internal combustion engine 30 includes an air filter 40, a first intake passage 41, a turbocharger 10, a second intake passage 42, an intercooler 43, an exhaust passage 45, and a three-way catalytic converter 46.

[0024] Air filter 40 is connected to turbocharger 10 via first intake passage 41. Turbocharger 10 is connected to intercooler 43 via second intake passage 42. Intercooler 43 is connected to intake manifold 33 of internal combustion engine 30. First exhaust port 31 and second exhaust port 32 are connected to turbocharger 10.

[0025] like Figure 1 and Figure 2 As shown, the turbocharger 10 is connected to the exhaust passage 45. A three-way catalytic converter 46 is connected downstream of the exhaust passage 45.

[0026] Intake air flows into the compressor housing 12 of the turbocharger 10 through the air filter 40 and the first intake passage 41. The intake air is compressed by the compressor impeller 11 disposed in the compressor housing 12. The compressed intake air flows into the intake manifold 33 through the second intake passage 42 and the intercooler 43.

[0027] Exhaust gas discharged from the internal combustion engine 30 flows into the turbine housing 15 of the turbocharger 10 through either the first exhaust port 31 or the second exhaust port 32. The exhaust gas flowing into the turbine housing 15 causes the turbine impeller 14 disposed within the turbine housing 15 to rotate. The exhaust gas flowing into the turbine housing 15 is discharged to the outside through the exhaust passage 45 and the three-way catalytic converter 46.

[0028] <Supercharger 10>

[0029] like Figure 1 and Figure 2 As shown, the turbocharger 10 includes a compressor impeller 11, a compressor housing 12, a connecting shaft 13, a turbine impeller 14, a turbine housing 15, and a connecting pipe 20.

[0030] The compressor housing 12 houses the compressor impeller 11. A first intake passage 41 and a second intake passage 42 are connected to the compressor housing 12.

[0031] like Figure 3 As shown, the connecting pipe 20 has a first passage 21, a second passage 22, a partition wall 23, and a contact surface 24. The connecting pipe 20 connects the turbine housing 15 to the internal combustion engine 30. The connecting pipe 20 contacts the internal combustion engine 30 via the contact surface 24. The connecting pipe 20 bends between the turbine housing 15 and the internal combustion engine 30. The connecting pipe 20 extends in a direction perpendicular to the contact surface 24 near it. The partition wall 23 divides the interior of the connecting pipe 20 into the first passage 21 and the second passage 22. The first passage 21 and the second passage 22 communicate with the first exhaust port 31 and the second exhaust port 32, respectively. Figure 3 The specified cross-section is shown as the section with the largest flow path cross-sectional area of ​​the vortex tube passage 18, which is orthogonal to the rotation axis of the turbine impeller 14.

[0032] like Figure 3 and Figure 4 As shown, if the flow direction E1 of the exhaust in the first passage 21 and the flow direction E2 of the exhaust in the second passage 22 are set as the flow direction of the exhaust in the connecting pipe 20, then the partition wall 23 extends from the contact surface 24 toward the flow direction of the exhaust in the connecting pipe 20.

[0033] The inner surface of the first passage 21 includes a first inner surface 21a defining the shape of the partition wall 23. The inner surface of the second passage 22 includes a second inner surface 22a defining the shape of the partition wall 23. The first inner surface 21a includes a first downstream inner surface 21b connected to the top end 26 of the partition wall 23, and a first upstream inner surface 21c connected to the first downstream inner surface 21b and extending toward the contact surface 24. The second inner surface 22a includes a second downstream inner surface 22b connected to the top end 26 of the partition wall 23, and a second upstream inner surface 22c connected to the second downstream inner surface 22b and extending toward the contact surface 24.

[0034] like Figure 4 and Figure 6 As shown, the first downstream inner surface 21b and the second downstream inner surface 22b are both planes and parallel to each other. In addition, the first upstream inner surface 21c is inclined relative to the second upstream inner surface 22c, such that the distance between the first upstream inner surface 21c and the second upstream inner surface 22c is wider the closer to the contact surface 24.

[0035] The portion of the partition wall 23 sandwiched between the first downstream inner surface 21b and the second downstream inner surface 22b is designated as the downstream portion 25. The flow path cross-sectional areas of adjacent portions of the first passage 21 and the second passage 22 that sandwich the downstream portion 25 are equal to each other.

[0036] like Figure 3 As shown, the turbine casing 15 is generally circular in cross-section. The turbine casing 15 houses a turbine impeller 14, which is also generally circular in cross-section. The turbine impeller 14 has a center of rotation 19. The impeller rotates through the center of rotation 19 and is perpendicular to... Figure 3 The imaginary line extending in the direction of the cross section shown is the axis of rotation.

[0037] like Figure 1 As shown, the compressor impeller 11 and the turbine impeller 14 are connected by a connecting shaft 13.

[0038] like Figure 3 As shown, the turbine housing 15 has a vortex passage 18 extending circumferentially along the turbine impeller 14 between the inner wall 16 of the turbine housing 15 and the outer peripheral surface 17 of the turbine impeller 14. The vortex passage 18 is a passage communicating with the first passage 21 and the second passage 22 of the connecting pipe 20, and is a passage through which the exhaust gas passing through the first passage 21 and the exhaust gas passing through the second passage 22 merge.

[0039] like Figure 1 and Figure 2As shown, a bypass passage 44 is provided in the turbine housing 15. The bypass passage 44 extends from the turbine housing 15 to the exhaust passage 45. An exhaust bypass valve 44a is provided in the bypass passage 44. Exhaust gas flows around the turbine impeller 14 through the bypass passage 44.

[0040] like Figure 3 As shown, the line segment connecting the rotation center 19 of the turbine impeller 14 to the downstream end 16a of the inner wall 16 in the exhaust flow direction E3 within the vortex passage 18 is designated as the first line segment H. A straight line orthogonal to the first line segment H and extending from the downstream end 16a along the exhaust flow in the vortex passage 18 is designated as the first imaginary line H1. Furthermore, the end of the partition wall 23 near the contact surface 24 is designated as the base end 27. The direction in which exhaust flows from the internal combustion engine 30 to the connecting pipe 20 is designated as the inflow directions e1 and e2. A straight line passing through the base end 27 and extending in a direction orthogonal to the inflow directions e1 and e2 is designated as the second imaginary line H2.

[0041] like Figures 3-5 As shown, the top end 26 of the partition wall 23 is located inside the connecting pipe 20 between the first imaginary line H1 and the second imaginary line H2. Furthermore, the shortest arc among the arcs passing through the top end 26 of the partition wall 23 and orthogonal to the first imaginary line H1 and the second imaginary line H2 at the first intersection point h1 on the first imaginary line H1 and the second intersection point h2 on the second imaginary line H2, is defined as the shortest arc A. In this case, the distance A1 between the first intersection point h1 and the top end 26 of the partition wall 23 along the shortest arc A is shorter than the distance A2 between the second intersection point h2 and the top end 26 of the partition wall 23 along the shortest arc A. Distance A1 is the length of the shortest arc A between the first intersection point h1 and the top end 26 of the partition wall 23. Distance A2 is the length of the shortest arc A between the second intersection point h2 and the top end 26 of the partition wall 23.

[0042] The function of this embodiment will be explained.

[0043] Because exhaust gas is intermittently discharged from the internal combustion engine 30 to the first exhaust port 31 and the second exhaust port 32, the pressure in the first exhaust port 31 and the second exhaust port 32 changes periodically, resulting in pressure pulsations. Furthermore, because the timing of exhaust gas discharge from the internal combustion engine 30 to the first exhaust port 31 and the second exhaust port 32 is different, the pressure in the first exhaust port 31 and the second exhaust port 32 at the same time will differ. Therefore, if the pressure in the first exhaust port 31 is higher than the pressure in the second exhaust port 32, exhaust gas discharged from the first exhaust port 31 to the connecting pipe 20 may flow back to the second exhaust port 32. Conversely, if the pressure in the second exhaust port 32 is higher than the pressure in the first exhaust port 31, exhaust gas discharged from the second exhaust port 32 to the connecting pipe 20 may flow back to the first exhaust port 31.

[0044] According to the above configuration, the connecting pipe 20 has a partition wall 23 that divides the interior of the connecting pipe 20 into a first passage 21 communicating with the first exhaust port 31 and a second passage 22 communicating with the second exhaust port 32. Therefore, it is difficult for exhaust to flow back from the first exhaust port 31 to the second exhaust port 32 or from the second exhaust port 32 to the first exhaust port 31.

[0045] like Figure 7 As shown, the closer the top end 26 of the partition wall 23 is to the vortex passage 18, the easier it is for the exhaust gas flowing in the first passage 21 and the second passage 22 to reach the vortex passage 18. Therefore, the effect of suppressing the exhaust gas backflow is higher. However, if the top end 26 protrudes into the vortex passage 18 beyond the first imaginary line H1, the pressure and velocity of the exhaust gas surrounding the vortex passage 18 may decrease due to the collision between the exhaust gas surrounding the vortex passage 18 and the partition wall 23.

[0046] Based on the above configuration, the position of the top end 26 of the partition wall 23 is defined such that the top end 26 is located between the first imaginary line H1 and the second imaginary line H2, so that the exhaust gas flowing in the vortex tube passage 18 is unlikely to collide with the partition wall 23.

[0047] The effects of this implementation method will be explained.

[0048] (1) The top end 26 of the partition wall 23 is located inside the connecting pipe 20 between the first imaginary line H1 and the second imaginary line H2.

[0049] With this configuration, because the turbocharger 10 has a partition wall 23, not only can the exhaust flow smoothly within the vortex passage 18, but it is also difficult for backflow of exhaust caused by pressure pulsations to occur. Furthermore, since the top end 26 of the partition wall 23 is located inside the connecting pipe 20 between the first imaginary line H1 and the second imaginary line H2, it is difficult for the exhaust within the vortex passage 18 to collide with the partition wall 23. Therefore, the exhaust flows smoothly within the vortex passage 18.

[0050] (2) The distance A1 between the first intersection point h1 along the shortest circular arc A and the top end 26 of the partition wall 23 is shorter than the distance A2 between the second intersection point h2 along the shortest circular arc A and the top end 26 of the partition wall 23.

[0051] If so Figure 8 If the length of the partition wall 23 is short as shown, the exhaust gas discharged from the first passage 21 and the second passage 22 will have difficulty flowing into the vortex passage 18, thus easily causing the aforementioned exhaust gas backflow.

[0052] Regarding this, based on the above configuration, the top end 26 of the partition wall 23 can be located at a position away from the first imaginary line H1 toward the connecting pipe 20, while the top end 26 of the partition wall 23 is close to the vortex tube passage 18. Therefore, it can effectively suppress the collision between the exhaust gas flowing in the vortex tube passage 18 and the partition wall 23, and suppress the backflow of exhaust gas from the first passage 21 to the second passage 22 and the backflow of exhaust gas from the second passage 22 to the first passage 21.

[0053] (3) The internal combustion engine 30 has cylinders C1, C2, C3, and C4 in the order of cylinder C1, C3, C4, and C2. Cylinder 1 includes cylinders C1 and C4. Cylinder 2 includes cylinders C2 and C3.

[0054] In a configuration different from the above, for example, where the first cylinder is cylinders C1 and C3, and the second cylinder is cylinders C4 and C2, the following problem arises: During a certain period, exhaust gas is continuously introduced from cylinders C1 and C3 into the first exhaust port 31. Therefore, the exhaust pressure in the first passage 21 becomes higher than the exhaust pressure in the second passage 22, and the pressure difference between the two passages 21 and 22 also increases. Similarly, during other periods, exhaust gas is continuously introduced from cylinders C4 and C2 into the second exhaust port 32. Therefore, the exhaust pressure in the second passage 22 becomes higher than the exhaust pressure in the first passage 21, and the pressure difference between the two passages 21 and 22 also increases. Thus, the aforementioned exhaust backflow is likely to occur.

[0055] Regarding this, according to the above configuration, the exhaust flows alternately into the first passage 21 and the second passage 22, thus suppressing the aforementioned exhaust backflow. Consequently, the exhaust easily flows from the first passage 21 and the second passage 22 into the vortex passage 18.

[0056] (4) The flow path cross-sectional areas of the downstream portion 25 sandwiched between the first passage 21 and the second passage 22 are equal.

[0057] Based on the above configuration, the force that assists the turbine impeller 14 in rotating due to exhaust flowing from the first passage 21 into the vortex passage 18 is unlikely to differ from the force that assists the turbine impeller 14 in rotating due to exhaust flowing from the second passage 22 into the vortex passage 18. Therefore, the speed of the turbine impeller 14 during rotation tends to remain constant. Consequently, it is difficult to generate pressure pulsations.

[0058] <Example of Change>

[0059] This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other within the scope of technical inconsistency.

[0060] • The flow path cross-sectional areas of the first passage 21 and the second passage 22, which are adjacent to the downstream portion 25, can also be different from each other.

[0061] In this specification, if the flow path cross-sectional area of ​​the first channel 21 is set as S1 and the flow path cross-sectional area of ​​the second channel 22 is set as S2, then the cases where S1 and S2 are equal include the following: That is, in addition to the cases where S1 and S2 are completely identical, the cases where 0.9 ≤ S1 / S2 ≤ 1.1 are also included.

[0062] • The first upstream inner surface 21c and the second upstream inner surface 22c can also be parallel to each other.

[0063] • In this specification, “parallel” is not limited to parallel in a strict sense. That is, the case where the flow direction of the exhaust gas flowing from the first passage 21 into the vortex passage 18 and the flow direction of the exhaust gas flowing from the second passage 22 into the vortex passage 18 are considered to be parallel, and the case where the second downstream inner surface 22b is inclined relative to the first downstream inner surface 21b, is also included in the “parallel” in this specification.

[0064] • The distance A1 between the first intersection point h1 on the shortest arc A and the top end 26 of the partition wall 23 can also be equal to the distance A2 between the second intersection point h2 on the shortest arc A and the top end 26 of the partition wall 23. Alternatively, the distance A1 between the first intersection point h1 on the shortest arc A and the top end 26 of the partition wall 23 can also be longer than the distance A2 between the second intersection point h2 on the shortest arc A and the top end 26 of the partition wall 23.

[0065] • The top 26 of the partition wall 23 can also be located on the first imaginary line H1. With this configuration, it is more difficult to generate backflow of exhaust from the first exhaust port 31 to the second exhaust port 32 and backflow of exhaust from the second exhaust port 32 to the first exhaust port 31.

[0066] • In this specification, “top 26 of partition wall 23” is not just a top in the strict sense, but a part of a certain size including top 26 and the surrounding part of top 26.

Claims

1. A turbocharger, wherein the turbocharger is a turbocharger for an internal combustion engine, wherein, The internal combustion engine has the following features: The first cylinder and the second cylinder, whose combustion stroke is at a different time from that of the first cylinder; and The first exhaust port connected to the first cylinder and the second exhaust port connected to the second cylinder, The booster includes: Turbine impeller; Turbine casing, housing the turbine impeller; and A connecting pipe connects the turbine housing to the internal combustion engine. The connecting pipe has: The contact surface contacts the internal combustion engine. The first passage is connected to the first exhaust port; The second passage is connected to the second exhaust port; and A partition wall, extending from the contact surface, divides the interior of the connecting tube into the first passage and the second passage. The turbine housing has a vortex passage extending circumferentially along the turbine impeller between the inner wall of the turbine housing and the outer peripheral surface of the turbine impeller. The vortex tube passage connects the first passage and the second passage, so that the exhaust gas passing through the first passage and the exhaust gas passing through the second passage merge. The cross-sectional area with the largest flow path cross-section in the vortex tube passage, which is orthogonal to the rotation axis of the turbine impeller, is the specified cross-section. When observing the specified cross-section, The line segment connecting the rotation center of the turbine impeller to the downstream end of the inner wall in the direction of exhaust flow within the vortex tube passage is designated as the first line segment. The straight line orthogonal to the first line segment and extending from the downstream end along the flow direction of the exhaust gas in the vortex tube passage is the first imaginary line. The partition wall has an end near the contact surface, i.e., a base end, and a top end located on the opposite side of the base end. The second imaginary line is a straight line extending through the base end in a direction orthogonal to the direction in which exhaust flows from the internal combustion engine to the connecting pipe. The top end of the partition wall is located inside the connecting pipe between the first imaginary line and the second imaginary line. When observing the specified cross-section The shortest arc is the arc that passes through the top of the partition wall and is orthogonal to both the first and second imaginary lines at the first intersection point on the first imaginary line and the second intersection point on the second imaginary line. The distance between the first intersection point along the shortest arc and the top of the partition wall is shorter than the distance between the second intersection point along the shortest arc and the top of the partition wall.

2. The booster according to claim 1, The internal combustion engine has cylinders N1, N2, N3, and N4. The N1, N2, N3, and N4 cylinders are configured such that the combustion stroke occurs in this sequence. The first cylinder includes cylinder N1 and cylinder N3. The second cylinder includes the N2 cylinder and the N4 cylinder.

3. The booster according to claim 1, The inner surface of the first passage includes a first inner surface defining the shape of the partition wall, the first inner surface including a first downstream inner surface connected to the top end of the partition wall. The inner surface of the second passage includes a second inner surface defining the shape of the partition wall, the second inner surface including a second downstream inner surface connected to the top end of the partition wall. The portion of the partition wall whose shape is defined by the first downstream inner surface and the second downstream inner surface is the downstream portion. When observing the specified cross-section, the flow path cross-sectional areas of the adjacent portions of the first passage and the second passage, which sandwich the downstream portion, are equal to each other.

4. The booster according to claim 3, The first inner surface includes a first upstream inner surface that connects to the first downstream inner surface and extends toward the contact surface of the connecting pipe. The second inner surface includes a second upstream inner surface that connects to the second downstream inner surface and extends toward the contact surface of the connecting pipe. When observing the specified cross-section The first downstream inner surface and the second downstream inner surface are parallel to each other. The first upstream inner surface is inclined relative to the second upstream inner surface in such a way that the distance between the first upstream inner surface and the second upstream inner surface is wider the closer they are to the contact surface.

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