A design method for an engine's pulse exhaust system and the pulse exhaust system itself.

Abstract

This invention belongs to the field of engine technology, and particularly relates to a design method and system for an engine's pulse exhaust system. The design method includes: determining the number and location of turbochargers; determining the number of exhaust pipes and the number of exhaust branch pipes connected to each exhaust pipe based on the number of cylinders in a bank of cylinders; installing expansion joints between adjacent exhaust branch pipes, between the exhaust pipe and the intake branch pipe of the exhaust manifold, and between the outlet flange and the turbine inlet flange; and performing thermal coupling calculations on the pulse exhaust system. The pulse exhaust system is manufactured using this design method. This invention solves the problems of radial unequal deformation of the exhaust pipe caused by heating, which can easily lead to exhaust pipe breakage, and radial torsional deformation of the expansion joints, which affects the fatigue life of the pulse exhaust system, thus improving fatigue life.

Description

Technical Field

[0001] This invention belongs to the field of engine technology, and particularly relates to a design method for an engine pulse exhaust system and the pulse exhaust system itself. Background Technology

[0002] Currently, many engines use pulse exhaust systems for exhaust. Pulse exhaust systems lead out the exhaust manifolds of each cylinder independently or in specific groups, so that the high-pressure exhaust pulses of each cylinder or group of cylinders do not interfere with each other in time, thereby preserving the energy of the exhaust pressure wave and enabling more efficient operation of the turbocharger.

[0003] Existing pulse exhaust systems have expansion joints connected in series on the exhaust pipe to absorb stress caused by thermal expansion and contraction, vibration, displacement, and installation errors, thus preventing structural damage.

[0004] When the engine is running, the high-temperature exhaust gas enters the exhaust pipe through the exhaust manifold. When the exhaust pipe is heated, it is prone to radial deformation, which can cause the exhaust pipe to crack due to excessive thermal stress or the expansion joint to twist radially, thus drastically shortening the fatigue life of the exhaust system. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a design method and a pulse exhaust system for an engine, which aims to solve the problems that radial unequal deformation caused by heat in the exhaust pipe can easily lead to exhaust pipe rupture and radial torsional deformation of the expansion joint can affect the fatigue life of the pulse exhaust system.

[0006] This invention discloses a design method for an engine's pulse exhaust system, which includes the following steps:

[0007] S10. The number of turbochargers is set according to the engine's power, number of cylinders, and cylinder arrangement, and the position of the turbochargers is set according to the engine's structure;

[0008] The straight line where the connecting flange of the exhaust branch pipe connected to the outlet of one bank of cylinders of the engine is located is set as line Y0. The reference line of the exhaust pipes connected to the exhaust branch pipes arranged at intervals along the Z direction is set as line Z0. Line Z0 is set parallel to line Y0 and line Z0 is located on the same horizontal plane. The center of the turbine housing of the turbocharger is set below line Y0 and line Z0. The turbine axis of the turbocharger is set along the Y direction. The bearing housing fixing hole of the turbocharger is flush with line Y0. The rotation angle of the turbocharger is θ. The distance between the center of the turbine housing and the axis of the turbine inlet of the turbine housing is Z6. The component of the distance between the center of the turbine housing and the axis of the turbine inlet in the Y direction is Z7, Z7 = Z6 × cosθ. The Z-direction distance between the center of the outlet flange of the exhaust manifold connected to the turbine inlet and line Z0 is set as Z5, Z5 = Z7.

[0009] S20. The number of exhaust pipes and the number of exhaust branch pipes connected to each exhaust pipe are set according to the number of cylinders in a row of cylinders of the engine. Expansion joints are respectively provided on the exhaust pipes between adjacent exhaust branch pipes, between the end of the exhaust pipe near the exhaust manifold and the intake branch pipe of the exhaust manifold, and between the outlet flange and the inlet flange of the turbine inlet.

[0010] The exhaust pipe is axially arranged along the X direction, and the distance between the axial direction of the exhaust pipe and the Y0 line is Yn. The main support fixedly connected to the exhaust manifold is set on the Z0 line and the bottom surface of the main support is flush with the Z0 line. The center line of the fixing hole of the main support is flush with the Y0 line. The distance between the center of the turbine inlet flange and the Y0 line is Y6, and the distance between the center of the turbine inlet flange and the axial direction of the intake branch of the exhaust manifold is Y5. Yn = Y5 + Y6.

[0011] S30. Perform thermal coupling calculation on the pulse exhaust system. Based on the results of the thermal coupling calculation, adjust the relative positions of the exhaust pipes in the Y and Z directions on both sides of the expansion joint in step S20, and perform thermal coupling calculation on the adjusted pulse exhaust system to verify the relative positions of the exhaust pipes in the Y and Z directions on both sides of each expansion joint.

[0012] As an improvement, the engine is an inline engine, and a set of pulse exhaust systems is provided for one bank of cylinders of the inline engine.

[0013] As an improvement, the engine is a V-type engine or a W-type engine, with a set of pulse exhaust systems provided for each bank of cylinders.

[0014] As an improvement, at least two of the exhaust pipes in step S20 are arranged in the same vertical plane and are evenly spaced along the Z direction, with the central axis of the at least two exhaust pipes being flush with the Z0 direction.

[0015] As an improvement, the number of cylinders in a bank of cylinders of the engine is greater than or equal to four and the number of cylinders is even, the number of exhaust pipes is half the number of cylinders, and each exhaust pipe is connected to two exhaust branch pipes.

[0016] The present invention also discloses a pulse exhaust system, corresponding to a bank of cylinders in an engine, including a turbocharger, an exhaust manifold, and at least one exhaust pipe. The exhaust pipe extends axially along the X direction, and at least two exhaust branch pipes are connected to each exhaust pipe. The connecting flanges of the exhaust branch pipes are arranged on the same straight line Y0. The axial direction of the exhaust pipe is parallel to the Y0 line. The reference line for the exhaust pipes arranged at intervals along the Z direction is set as the Z0 line. The Z0 line is parallel to the Y0 line and the Z0 line and the Y0 line are located on the same horizontal plane.

[0017] Expansion joints are respectively provided on the exhaust pipe between adjacent exhaust branch pipes, between the end of the exhaust pipe near the exhaust main pipe and the intake branch pipe on the corresponding side of the exhaust main pipe, and between the outlet flange of the exhaust main pipe and the inlet flange of the turbocharger turbine inlet;

[0018] The turbine housing of the turbocharger is located below the Y0 line. The turbine of the turbocharger is axially arranged along the Y direction. The bearing housing fixing hole of the turbocharger is flush with the Y0 line. The distance between the center of the turbine housing and the axis of the turbine inlet has a Y-axis component of Z7, Z7 = Z6 × cosθ, where θ is the rotation angle of the turbocharger and Z6 is the distance between the center of the turbine housing and the axis of the turbine inlet. The Z-axis distance between the center of the outlet flange of the exhaust manifold and the Z0 line is Z5, Z5 = Z7.

[0019] As an improvement, the engine is an inline engine, the number of cylinders of the inline engine is greater than or equal to four and the number of cylinders of the inline engine is an even number, the number of exhaust pipes is half the number of cylinders, and the exhaust pipes are arranged at intervals along the Z direction.

[0020] As an improvement, each exhaust pipe is connected to two exhaust branch pipes, one of which is connected to the end of the exhaust pipe away from the exhaust main pipe, and the other is connected to the end of the exhaust pipe near the exhaust main pipe. The expansion joint connected in series on the exhaust pipe between the two exhaust branch pipes is a middle expansion joint, and the expansion joint between the end of the exhaust pipe near the exhaust main pipe and the intake branch pipe of the exhaust main pipe is an end expansion joint.

[0021] As an improvement, at least two exhaust pipes are arranged in the same vertical plane and are evenly spaced along the vertical direction, and the central axis of at least two exhaust pipes is flush with the Z0 direction.

[0022] As an improvement, at least two of the exhaust pipes have corresponding central expansion joints, and at least two of the exhaust pipes have corresponding end expansion joints between the exhaust pipes and the intake branch pipes of the exhaust manifold.

[0023] After adopting the above technical solution, the beneficial effects of the present invention are:

[0024] The pulse exhaust system design method for the engine of the present invention includes the following steps:

[0025] S10. The number of turbochargers is determined according to the engine's power, number of cylinders, and cylinder arrangement, and the location of the turbochargers is determined according to the engine's structure.

[0026] The straight line where the connecting flange of the exhaust branch pipe connected to the exhaust port of one bank of cylinders of the engine is located is set as line Y0. The reference line of the exhaust pipes connected to the exhaust branch pipes along the Z direction is set as line Z0. Line Z0 is set parallel to line Y0 and line Z0 is located on the same horizontal plane. The center of the turbocharger turbine housing is set below lines Y0 and Z0. The turbine axis of the turbocharger is set along the Y direction. The bearing housing fixing hole of the turbocharger is flush with line Y0. The rotation angle of the turbocharger is θ. The distance between the center of the turbine housing and the axis of the turbine inlet of the turbine housing is Z6. The component of the distance between the center of the turbine housing and the axis of the turbine inlet in the Y direction is Z7, Z7=Z6×cosθ. The Z-direction distance between the center of the outlet flange of the exhaust manifold connected to the turbine inlet and line Z0 is set as Z5, Z5=Z7.

[0027] S20. The number of exhaust pipes and the number of exhaust branch pipes connected to each exhaust pipe are set according to the number of cylinders in a bank of cylinders of the engine. Expansion joints are respectively installed on the exhaust pipes between adjacent exhaust branch pipes, between the end of the exhaust pipe near the exhaust manifold and the intake branch pipe of the exhaust manifold, and between the outlet flange and the inlet flange of the turbine inlet.

[0028] The exhaust pipe is axially arranged along the X direction. The distance between the exhaust pipe axis and the Y0 line is Yn. The main support fixedly connected to the exhaust manifold is set on the Z0 line and the bottom surface of the main support is flush with the Z0 line. The center line of the fixing hole of the main support is flush with the Y0 line. The distance between the center of the turbine inlet flange and the Y0 line is Y6. The distance between the center of the turbine inlet flange and the axial direction of the intake branch of the exhaust manifold is Y5. Yn = Y5 + Y6.

[0029] S30. Perform thermal coupling calculation on the pulse exhaust system. Based on the results of the thermal coupling calculation, adjust the relative positions of the exhaust pipes in the Y and Z directions on both sides of the expansion joint in step S20, and perform thermal coupling calculation on the adjusted pulse exhaust system again to verify the relative positions of the exhaust pipes in the Y and Z directions on both sides of the expansion joint.

[0030] The pulse exhaust system of the present invention corresponds to a row of cylinders of an engine, including a turbocharger, an exhaust manifold and at least one exhaust pipe. The exhaust pipe extends axially along the X direction. At least two exhaust branch pipes are connected to each exhaust pipe. The connecting flanges of the exhaust branch pipes are arranged on the same straight line Y0. The axial direction of the exhaust pipe is parallel to the Y0 line. The reference line for the exhaust pipes arranged at intervals along the Z direction is set as the Z0 line. The Z0 line is parallel to the Y0 line and the Z0 line and the Y0 line are located on the same horizontal plane.

[0031] Expansion joints are installed on the exhaust pipes between adjacent exhaust branch pipes, between the end of the exhaust pipe near the exhaust manifold and the corresponding side of the exhaust manifold intake branch pipe, and between the outlet flange of the exhaust manifold and the inlet flange of the turbocharger turbine inlet.

[0032] The turbocharger's turbine housing center is located below line Y0. The turbocharger's turbine axis is set along the Y direction. The turbocharger's bearing housing fixing hole is flush with line Y0. The distance between the turbine housing center and the turbine inlet axis in the Y direction is Z7, Z7 = Z6 × cosθ, where θ is the turbocharger's rotation angle and Z6 is the distance between the turbine housing center and the turbine inlet axis. The Z-direction distance between the outlet flange center of the exhaust manifold's main outlet and line Z0 is Z5, Z5 = Z7.

[0033] Because the exhaust pipes are arranged along the X-axis (horizontal direction) and parallel to the straight line Y0 of the connecting flange of the exhaust branch pipe connected to a row of cylinders in the engine, the axial Y-axis distance and Z-axis distance of each exhaust pipe are equal. This avoids the exhaust pipe from cracking due to uneven radial deformation caused by heat. At the same time, because the Y-axis distance and Z-axis distance on both sides of the middle expansion joint are equal, the Y-axis distance and Z-axis distance on both sides of the end expansion joint are equal, and the Y-axis distance and Z-axis distance on both sides of the exhaust manifold expansion joint are equal, radial torsional deformation of the expansion joint is avoided. This solves the problem that uneven radial deformation caused by heat can easily lead to exhaust pipe cracking, and the problem that radial torsional deformation of the expansion joint affects the fatigue life of the pulse exhaust system, thus improving the fatigue life of the pulse exhaust system. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating the design method of the pulse exhaust system for an engine according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the main structure of the pulse exhaust system according to an embodiment of the present invention;

[0036] Figure 3 This is a top view of the pulse exhaust system according to an embodiment of the present invention;

[0037] Figure 4 This is a three-dimensional structural schematic diagram of the pulse exhaust system according to an embodiment of the present invention;

[0038] Among them, 10. Turbocharger; 11. Turbine housing; 12. Turbine inlet; 13. Bearing housing; 21. First exhaust pipe; 22. Second exhaust pipe; 23. Third exhaust pipe; 24. Fourth exhaust pipe; 31. First exhaust branch pipe; 32. Second exhaust branch pipe; 33. Third exhaust branch pipe; 34. Fourth exhaust branch pipe; 35. Fifth exhaust branch pipe; 36. Sixth exhaust branch pipe; 37. Seventh exhaust branch pipe; 38. Eighth exhaust branch pipe; 411. First middle section Expansion joint; 412, First end expansion joint; 421, Second middle expansion joint; 422, Second end expansion joint; 431, Third middle expansion joint; 432, Third end expansion joint; 441, Fourth middle expansion joint; 442, Fourth end expansion joint; 50, Exhaust main pipe; 51, Outlet flange; 52, First exhaust main pipe; 53, Second exhaust main pipe; 61, First exhaust main pipe expansion joint; 62, Second exhaust main pipe expansion joint; 70, Main support. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0040] Figures 1 to 4 This is a schematic diagram of the design method and structure of the pulse exhaust system for an engine according to an embodiment of the present invention. Figure 1 A flowchart illustrating the design method of an engine pulse exhaust system according to an embodiment of the present invention is shown. Figure 2 A front view schematic diagram of the pulse exhaust system according to an embodiment of the present invention is shown. Figure 3 A top view of the pulse exhaust system according to an embodiment of the present invention is shown. Figure 4 A three-dimensional structural schematic diagram of a pulse exhaust system according to an embodiment of the present invention is shown. For ease of description, only the parts relevant to the present invention are shown in the figure.

[0041] It should be noted that the directional indications (e.g., up, down, forward, backward, etc.) involved in this invention are only used to explain the relative positional relationship between the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly. If the descriptions of "first", "second", etc. involved in this invention are used for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated.

[0042] For ease of description and understanding, we define the horizontal direction as X, the vertical direction as Z, and the transverse direction as Y. The Y direction is perpendicular to the X and Z directions. The axial direction of the exhaust pipe is X, the transverse radial direction of the exhaust pipe is Y, and the vertical radial direction of the exhaust pipe is Z. When there are two or more exhaust pipes, the exhaust pipes are arranged at intervals along the Z direction. The straight line where the connecting flange of the exhaust branch pipe connected to the exhaust port of one row of cylinders of the engine is located is set as the Y0 line. The reference line for the interval arrangement of exhaust pipes along the Z direction is set as the Z0 line. The Z0 line is set parallel to the Y0 line, and the Z0 line and the Y0 line are located on the same horizontal plane.

[0043] The existing pulse exhaust system includes a turbocharger 10, an exhaust manifold 50 and at least one exhaust pipe. The exhaust manifold 50 is located between the at least one exhaust pipe and the turbine inlet 12 of the turbocharger 10. The intake branch pipes of the exhaust manifold 50 correspond one-to-one with the exhaust pipes and are connected. The main outlet of the exhaust manifold 50 is connected to the turbine inlet 12.

[0044] like Figure 1 , Figure 2 and Figure 3 As shown in the figure, an embodiment of the present invention discloses a design method for a pulse exhaust system of an engine, including the following steps:

[0045] S10. The number of turbochargers 10 is set according to the engine power, number of cylinders and cylinder arrangement, and the position of the turbochargers 10 is set according to the engine structure.

[0046] The straight line where the connecting flange of the exhaust branch pipe connected to the exhaust port of a row of cylinders of the engine is located is set as line Y0. The reference line of the exhaust pipes connected to the exhaust branch pipes arranged at intervals along the Z direction is set as line Z0. Line Z0 is set parallel to line Y0 and line Z0 is located on the same horizontal plane as line Y0. The center of turbine housing 11 of turbocharger 10 is set below line Y0 and line Z0. The turbine axis of turbocharger 10 is set along the Y direction. The fixing hole of bearing housing 13 of turbocharger 10 is flush with line Y0. The rotation angle of turbocharger 10 is θ. The distance between the center of turbine housing 11 and the axis of turbine inlet 12 of turbine housing 11 is Z6. The component of the distance between the center of turbine housing 11 and the axis of turbine inlet 12 of turbine housing 11 in the Y direction is Z7, Z7=Z6×cosθ. The Z-direction distance between the center of the outlet flange 51 of the exhaust manifold 50 connected to turbine inlet 12 and line Z0 is set as Z5, Z5=Z7.

[0047] Specifically, when the engine is an inline engine, a pulse exhaust system is set up for each bank of cylinders in the inline engine; when the engine is a V-type or W-type engine, a pulse exhaust system is set up for each bank of cylinders.

[0048] In some other embodiments, for high-power inline engines, two turbochargers 10 may be provided to reduce costs.

[0049] S20. The number of exhaust pipes and the number of exhaust branch pipes connected to each exhaust pipe are set according to the number of cylinders in a row of cylinders of the engine. Expansion joints are respectively provided on the exhaust pipes between adjacent exhaust branch pipes, between the end of the exhaust pipe near the exhaust manifold 50 and the intake branch pipe on the corresponding side of the exhaust manifold 50, and between the outlet flange 51 of the exhaust manifold 50 and the inlet flange of the turbine inlet 12.

[0050] The exhaust pipes are arranged along the X direction. When there are two or more exhaust pipes, they are arranged side by side along the Z direction at intervals. The distance between the axial direction of the exhaust pipe and the Y0 line is Yn. The distance between the connecting flanges of at least two exhaust branch pipes connected to the same exhaust pipe and the axis of the exhaust pipe is equal. The main support 70, which is fixedly connected to the exhaust main pipe 50, is set on the Z0 line and the bottom surface of the main support 70 is flush with the Z0 line. The center line of the fixing hole of the main support 70 is flush with the Y0 line. The distance between the center of the inlet flange of the turbine inlet 12 of the turbine housing 11 and the Y0 line is Y6. The distance between the center of the inlet flange of the turbine inlet 12 of the turbine housing 11 and the axial direction of the intake branch pipe of the exhaust main pipe 50 is Y5. Yn = Y5 + Y6.

[0051] Among them, the expansion joint connected in series on the exhaust pipe between adjacent exhaust branch pipes is the middle expansion joint, the expansion joint between the end of the exhaust pipe near the exhaust main pipe 50 and the branch inlet on the corresponding side of the exhaust main pipe 50 is the end expansion joint, and the expansion joint between the outlet flange 51 of the exhaust main pipe 50 and the inlet flange of the turbine inlet 12 is the exhaust main pipe expansion joint.

[0052] Specifically, for an inline three-cylinder engine, there is a turbocharger 10 and an exhaust pipe. The three exhaust manifolds corresponding to the three cylinders of the inline three-cylinder engine are respectively connected to the exhaust pipe. The exhaust manifold connected to the first cylinder of the inline three-cylinder engine is connected to the end of the exhaust pipe away from the turbocharger 10, the exhaust manifold connected to the second cylinder of the inline three-cylinder engine is connected to the middle of the exhaust pipe, and the exhaust manifold connected to the third cylinder of the inline three-cylinder engine is connected to the end of the exhaust pipe near the turbocharger 10. Expansion joints are connected in series on the exhaust pipes between the exhaust manifolds of the first and second cylinders of the inline three-cylinder engine, and between the exhaust manifolds of the second and third cylinders of the inline three-cylinder engine.

[0053] In some other embodiments, for an inline engine with four or more cylinders and an even number of cylinders, a turbocharger 10 is provided, the number of exhaust pipes is half the number of cylinders, and the exhaust pipes are arranged at intervals along the Z direction. Common engines include inline four-cylinder engines, inline six-cylinder engines, inline eight-cylinder engines, and inline twelve-cylinder engines.

[0054] For ease of understanding, combined with Figure 2 , Figure 3 and Figure 4 Let's take an inline eight-cylinder engine as an example:

[0055] The engine is an inline eight-cylinder engine, with eight cylinders designated as cylinder 1, cylinder 2, cylinder 3, cylinder 4, cylinder 5, cylinder 6, cylinder 7, and cylinder 8. There are four exhaust pipes. Following the firing order of the cylinders in the inline eight-cylinder engine, the exhaust branch pipes connected to cylinders 1 and 8 are connected to the same exhaust pipe; the exhaust branch pipes connected to cylinders 2 and 7 are connected to the same exhaust pipe; the exhaust branch pipes connected to cylinders 3 and 6 are connected to the same exhaust pipe; and the exhaust branch pipes connected to cylinders 4 and 5 are connected to the same exhaust pipe. Two exhaust branch pipes corresponding to the same exhaust pipe are respectively located at both ends of the exhaust pipe. An expansion joint is connected in series on the exhaust pipe between the two exhaust branch pipes, serving as a central expansion joint. The exhaust manifold 50 has intake branch pipes corresponding to each of the four exhaust pipes. Expansion joints are connected in series between the ends of the four exhaust pipes near the turbocharger 10 and the four intake branch pipes of the exhaust manifold 50, serving as end expansion joints.

[0056] Specifically, the eight exhaust manifolds connected to the eight cylinders are designated as the first exhaust manifold 31, the second exhaust manifold 32, the third exhaust manifold 33, the fourth exhaust manifold 34, the fifth exhaust manifold 35, the sixth exhaust manifold 36, the seventh exhaust manifold 37, and the eighth exhaust manifold 38. Correspondingly, four exhaust manifolds are arranged vertically at intervals, from bottom to top as the first exhaust manifold 21, the second exhaust manifold 22, the third exhaust manifold 23, and the fourth exhaust manifold 24. The first exhaust manifold 31 and the eighth exhaust manifold 38 are connected to the first exhaust manifold 21. A first central expansion joint 411 is connected in series on the first exhaust manifold 21 between the first exhaust manifold 31 and the eighth exhaust manifold 38. A first end expansion joint 412 is connected in series between the end of the first exhaust manifold 21 near the turbocharger and the corresponding intake manifold. The second exhaust manifold 32 and the seventh exhaust manifold 37 are connected to the second exhaust manifold 22. A second central expansion joint 421 is connected in series on the second exhaust pipe 22 between pipe 32 and the seventh exhaust branch pipe 37. A second end expansion joint 422 is connected in series between the end of the second exhaust pipe 22 near the turbocharger and the corresponding intake branch pipe. The third exhaust branch pipe 33 and the sixth exhaust branch pipe 36 are connected to the third exhaust pipe 23. A third central expansion joint 431 is connected in series on the third exhaust pipe 23 between the third exhaust branch pipe 33 and the sixth exhaust branch pipe 36. A third end expansion joint 432 is connected in series between the end of the third exhaust branch pipe 33 near the turbocharger and the corresponding intake branch pipe. The fourth exhaust branch pipe 34 and the fifth exhaust branch pipe 35 are connected to the fourth exhaust pipe 24. A fourth central expansion joint 441 is connected in series on the fourth exhaust pipe 24 between the fourth exhaust branch pipe 34 and the fifth exhaust branch pipe 35. A fourth end expansion joint 442 is connected in series between the end of the fourth exhaust pipe 24 near the turbocharger and the corresponding intake branch pipe.

[0057] Furthermore, at least two exhaust pipes are arranged on the same vertical plane and are evenly spaced along the vertical direction, and the central axis of at least two exhaust pipes is flush with the Z0 direction; the middle expansion joints on at least two exhaust pipes are correspondingly arranged, and the end expansion joints between the ends of at least two exhaust pipes near the turbocharger 10 and the intake branch pipe of the exhaust manifold 50 are correspondingly arranged.

[0058] like Figure 2 and Figure 4 As shown, the turbocharger 10 has two intake ports on its turbine inlet 12, and correspondingly, the exhaust manifold 50 has two exhaust outlets, which are fixed to the outlet flange 51 respectively.

[0059] Specifically, the exhaust manifold 50 includes a first exhaust manifold 52 and a second exhaust manifold 53. The first exhaust manifold 52 and the second exhaust manifold 53 are respectively provided with two intake branch pipes and one exhaust outlet. The exhaust outlet of the first exhaust manifold 52 and the exhaust outlet of the second exhaust manifold 53 are respectively fixed to the outlet flange 51.

[0060] The corresponding exhaust manifold expansion joints include a first exhaust manifold expansion joint 61 and a second exhaust manifold expansion joint 62, which are respectively disposed between the two exhaust outlets of the exhaust manifold 50 and the two intake ports of the turbocharger 10.

[0061] In some other embodiments, the turbocharger 10 has a turbine inlet 12 with an intake port, and correspondingly, the exhaust manifold 50 has an exhaust outlet.

[0062] S30. Perform thermal coupling calculations on the pulse exhaust system. Based on the results of the thermal coupling calculations, adjust the relative positions of the exhaust pipes on both sides of the expansion joint in the Y and Z directions. Perform thermal coupling calculations on the adjusted pulse exhaust system to verify the relative positions of the exhaust pipes on both sides of each expansion joint in the Y and Z directions.

[0063] Specifically, a 3D model of the designed pulse exhaust system is created, and the engine parameters, material properties (such as elastic modulus, Poisson's ratio, coefficient of linear expansion, density, thermal conductivity, etc.) of the exhaust manifold, exhaust pipe, exhaust manifold 50, main support 70, and expansion joint are input into a thermo-mechanical coupling simulation software (such as Abaqus). This allows the output of thermal deformation at various points in the pulse exhaust system. Based on the simulation calculation structure, the positions of the pipe sections on both sides of the expansion joint are adjusted, and then thermal coupling calculations of the exhaust pipe are performed for verification.

[0064] Thermal coupling calculation is a well-known technology in the field of engine engineering, and will not be elaborated here.

[0065] For ease of understanding, the Y-axis thermal expansion and Z-axis thermal expansion on both sides of the central expansion joint, end expansion joint, and exhaust manifold expansion joint are explained as follows:

[0066] The formula for calculating thermal expansion is ΔL=α·L·ΔT, where α is the coefficient of thermal expansion, L is the dimension in the direction of thermal expansion, and ΔT is the temperature change. That is, thermal expansion is directly proportional to the structural dimensions. If two components are made of the same material, have the same dimension in the direction of thermal deformation, and have the same temperature change, then their thermal expansion is the same.

[0067] Regarding thermal expansion in the Y direction:

[0068] like Figure 3As shown, since the exhaust pipe's axial direction is horizontal (X-direction), the connecting flange of the exhaust branch pipe connected to the exhaust port of one bank of cylinders in the engine is located on line Y0. The exhaust pipe's axial direction is parallel to line Y0. During installation, the connecting flanges of the exhaust branch pipes are fixed to the engine. Specifically, the Y-direction distance between the two sides of the central expansion joint and line Y0 is Yn, meaning the Y-direction distances between the two sides of the central expansion joint and line Y0 are equal. The Y-direction distance between the left side of the end expansion joint and line Y0 is Yn, and the Y-direction distance between the left side of the end expansion joint and line Y0 is Y5 + Y6. Since Yn = Y5 + Y6, the Y-direction distances on both sides of the end expansion joint are equal. The Y-direction distance between the two sides of the exhaust manifold expansion joint and line Y0 is Y6, meaning the Y-direction distances between the two sides of the exhaust manifold expansion joint and line Y0 are equal. In other words, the central expansion joint, end expansion joint, and exhaust manifold expansion joint will not experience Y-direction twisting.

[0069] Specifically, the Y-direction distance Yn on both sides of the first central expansion joint 411 is Y1, the Y-direction distance Yn on both sides of the second central expansion joint 421 is Y2, the Y-direction distance Yn on both sides of the third central expansion joint 431 is Y3, and the Y-direction distance Yn on both sides of the fourth central expansion joint 441 is Y4.

[0070] The Y-direction distance Yn on the left side of the first end expansion joint 412 is Y1, and the Y-direction distance Yn on the right side of the first end expansion joint 412 is Y1, Y1=Y5+Y6; the Y-direction distances on the left side of the second end expansion joint 422 are all Y2, and the Y-direction distance Yn on the right side of the second end expansion joint 422 is Y2, Y2=Y5+Y6; the Y-direction distances on the left side of the third end expansion joint 432 are all Y3, and the Y-direction distance Yn on the right side of the third end expansion joint 432 is Y3, Y3=Y5+Y6; the Y-direction distances on the left side of the fourth end expansion joint 442 are all Y4, and the Y-direction distance Yn on the right side of the fourth end expansion joint 442 is Y4, Y4=Y5+Y6; that is, Y1=Y2=Y3=Y4, and the four exhaust pipes are located in the same vertical plane.

[0071] Regarding thermal expansion in the Z direction:

[0072] like Figure 2 As shown, since the Z0 line is set parallel to the Y0 line and the Z0 line and the Y0 line are on the same horizontal plane, the exhaust pipe above the Z0 line deforms upward with the Z0 line as the reference, and the exhaust pipe below the Z0 line deforms downward with the Z0 line as the reference.

[0073] Since the exhaust pipe is axially arranged in the horizontal direction (X direction), and at least two exhaust pipes are arranged side by side at intervals in the vertical direction (Z direction), the Z-direction distance between the two sides of the middle expansion joint and the Z0 line on the exhaust pipe is Zn, and the Z-direction distance between the two sides of the middle expansion joint and the Z0 line is equal. The Z-direction distance between the two sides of the end expansion joint and the Z0 line is Zn, and the Z-direction distance between the two sides of the end expansion joint and the Z0 line is equal. In other words, the middle expansion joint and the end expansion joint will not produce Z-direction twist on both sides.

[0074] Since the main support 70, which is fixedly connected to the exhaust manifold 50, is located above the Z0 line, the bottom surface of the main support 70 is flush with the Z0 line, and the center line of the fixing hole of the main support 70 is flush with the Y0 line, the outlet side of the exhaust manifold 50 deforms downward, that is, the left side of the exhaust manifold expansion joint deforms downward, and the Z-direction distance of the outlet of the exhaust manifold 50 is Z5. At the same time, since the axis of the turbine inlet 12 of the turbine housing 11 is located below the center of the turbine housing 11, the turbine inlet 12 deforms downward, that is, the right side of the exhaust manifold expansion joint deforms downward, and the Z-direction distance at the turbine inlet 12 is Z7. Z7 = Z6 × cosθ. When Z5 = Z7, the Z-direction distances on both sides of the exhaust manifold expansion joint are equal, and the exhaust manifold expansion joint will not produce Z-direction twisting.

[0075] Specifically, the Z0 line is located between the second exhaust pipe 22 and the third exhaust pipe 23. The Z-direction distance Zn on both sides of the first middle expansion joint 411 is Z1, the Z-direction distance Zn on both sides of the second middle expansion joint 421 is Z2, the Z-direction distance Zn on both sides of the third middle expansion joint 431 is Z3, and the Z-direction distance Zn on both sides of the fourth middle expansion joint 441 is Z4. The Z-direction distance Zn on the left side of the first end expansion joint 412 is Z1, and the Z-direction distance Zn on the right side of the first end expansion joint 412 is Z1. The Z-direction distance on the left side of the second end expansion joint 422 is Z2, and the Z-direction distance Zn on the right side of the second end expansion joint 422 is Z2. The Z-direction distance on the left side of the third end expansion joint 432 is Z3, and the Z-direction distance Zn on the right side of the third end expansion joint 432 is Z3. The Z-direction distance on the left side of the fourth end expansion joint 442 is Z4, and the Z-direction distance Zn on the right side of the fourth end expansion joint 442 is Z4.

[0076] Because the exhaust pipes are arranged along the X-direction (horizontal direction) and parallel to the straight line Y0 of the connecting flange of the exhaust branch pipe connected to a row of cylinders in the engine, the axial Y-direction distance and Z-direction distance of each exhaust pipe are equal. This avoids the exhaust pipe from cracking due to radial unequal deformation caused by heat. At the same time, because the Y-direction distance and Z-direction distance on both sides of the middle expansion joint are equal, the Y-direction distance and Z-direction distance on both sides of the end expansion joint are equal, and the Y-direction distance and Z-direction distance on both sides of the exhaust manifold expansion joint are equal, radial torsional deformation of the expansion joint is avoided. The pulse exhaust system manufactured by the pulse exhaust system design method of the present invention solves the problem that radial unequal deformation caused by heat in the exhaust pipe can easily lead to exhaust pipe cracking and that radial torsional deformation of the expansion joint affects the fatigue life of the pulse exhaust system, thereby improving the fatigue life of the pulse exhaust system.

[0077] This invention also discloses a pulse exhaust system, corresponding to a bank of cylinders in an engine, including a turbocharger 10, an exhaust manifold 50, and at least one exhaust pipe. The exhaust pipe extends axially along the X direction, and at least two exhaust branch pipes are connected to each exhaust pipe. The connecting flanges of the exhaust branch pipes are located on the same straight line Y0, and the axial direction of the exhaust pipe is parallel to the Y0 line.

[0078] Expansion joints are respectively installed on the exhaust pipe between adjacent exhaust branch pipes, between the end of the exhaust pipe near the exhaust main pipe 50 and the intake branch pipe on the corresponding side of the exhaust main pipe 50, and between the outlet flange 51 of the exhaust main pipe 50 and the inlet flange of the turbine inlet 12.

[0079] The center of the turbine housing 11 of the turbocharger 10 is located below the Y0 line. The turbine axis of the turbocharger 10 is set along the Y direction. The fixing hole of the bearing housing 13 of the turbocharger 10 is flush with the Y0 line. The component of the distance in the Y direction between the center of the turbine housing 11 and the axis of the turbine inlet 12 of the turbine housing 11 is Z7, Z7 = Z6 × cosθ, where θ is the rotation angle of the turbocharger 10 and Z6 is the distance between the center of the turbine housing 11 and the axis of the turbine inlet 12 of the turbine housing 11. The Z-direction distance between the center of the outlet flange 51 of the exhaust manifold 50 and the Z0 line is Z5, Z5 = Z7.

[0080] Specifically, the expansion joint connected in series on the exhaust pipe between adjacent exhaust branch pipes is the middle expansion joint, the expansion joint between the end of the exhaust pipe near the exhaust main pipe 50 and the branch inlet on the corresponding side of the exhaust main pipe 50 is the end expansion joint, and the expansion joint between the outlet flange 51 of the exhaust main pipe 50 and the inlet flange of the turbine inlet 12 is the exhaust main pipe expansion joint.

[0081] In this embodiment of the invention, the engine is an inline engine with four or more cylinders and an even number of cylinders. The number of exhaust pipes is half the number of cylinders, and the exhaust pipes are arranged at intervals along the Z-direction.

[0082] Specifically, each exhaust pipe is connected to two exhaust branch pipes. One exhaust branch pipe is connected to the end of the exhaust pipe furthest from the main exhaust pipe 50, and the other exhaust branch pipe is connected to the end of the exhaust pipe closest to the main exhaust pipe 50. For example, when the engine is an inline four-cylinder engine, there are two exhaust pipes; when the engine is an inline six-cylinder engine, there are three exhaust pipes; when the engine is an inline eight-cylinder engine, there are four exhaust pipes; and when the engine is an inline twelve-cylinder engine, there are six exhaust pipes.

[0083] Furthermore, the baseline for the exhaust pipes arranged at intervals along the Z direction is set as the Z0 line, which is parallel to the Y0 line and lies on the same horizontal plane as the Y0 line; at least two exhaust pipes are arranged on the same vertical plane and are evenly spaced along the vertical direction, and the central axis of at least two exhaust pipes is aligned with the Z0 direction.

[0084] Typically, at least two exhaust pipes have corresponding central expansion joints, and at least two exhaust pipes have corresponding end expansion joints between the ends near the turbocharger 10 and the intake branch pipe of the exhaust manifold 50.

[0085] For inline engines, a set of the aforementioned pulse exhaust system is provided.

[0086] like Figure 2 , Figure 3 and Figure 4 As shown, the engine is an inline eight-cylinder engine with four exhaust pipes. From bottom to top, the four exhaust pipes are designated as first exhaust pipe 21, second exhaust pipe 22, third exhaust pipe 23, and fourth exhaust pipe 24. Corresponding to the eight cylinders of the inline eight-cylinder engine, there are first exhaust branch pipes 31, second exhaust branch pipes 32, third exhaust branch pipes 33, fourth exhaust branch pipes 34, fifth exhaust branch pipes 35, sixth exhaust branch pipes 36, seventh exhaust branch pipes 37, and eighth exhaust branch pipes 38. Among them, first exhaust branch pipes 31 and eighth exhaust branch pipes 38 are connected to first exhaust pipe 21, second exhaust branch pipes 32 and seventh exhaust branch pipes 37 are connected to second exhaust pipe 22, third exhaust branch pipes 33 and sixth exhaust branch pipes 36 are connected to third exhaust pipe 23, and fourth exhaust branch pipes 34 and fifth exhaust branch pipes 35 are connected to fourth exhaust pipe 24.

[0087] In some other embodiments, the engine is a V-type engine, and each bank of cylinders in the V-type engine is provided with a set of the above-mentioned pulse exhaust system.

[0088] In embodiments of the present invention, such as Figure 2 and Figure 4 As shown, the turbocharger 10 has two intake ports on its turbine inlet 12, and correspondingly, the exhaust manifold 50 has two exhaust outlets, which are fixed to the outlet flange 51 respectively.

[0089] Specifically, the exhaust manifold 50 includes a first exhaust manifold 52, a second exhaust manifold 53, and an outlet flange 51. The first exhaust manifold 52 and the second exhaust manifold 53 are each provided with two intake branch pipes and one exhaust outlet. The exhaust outlet of the first exhaust manifold 52 and the exhaust outlet of the second exhaust manifold 53 are respectively fixed to the outlet flange 51.

[0090] Correspondingly, the exhaust manifold expansion joint includes a first exhaust manifold expansion joint 61 and a second exhaust manifold expansion joint 62, which are respectively disposed between the two exhaust outlets of the exhaust manifold 50 and the two intake ports of the turbocharger 10.

[0091] In some other embodiments, the turbocharger 10 has a turbine inlet 12 with an intake port, and correspondingly, the exhaust manifold 50 has an exhaust outlet.

[0092] The above are examples of the preferred embodiments of the present invention, and the parts not described in detail are common knowledge to those skilled in the art. The scope of protection of the present invention is determined by the content of the claims, and any equivalent modifications made based on the technical teachings of the present invention are also within the scope of protection of the present invention.

Claims

1. A design method for a pulse exhaust system of an engine, characterized in that, Includes the following steps: S10. The number of turbochargers (10) is set according to the power, number of cylinders and arrangement of cylinders of the engine, and the position of the turbochargers (10) is set according to the structure of the engine; The straight line where the connecting flange of the exhaust branch pipe connected to the outlet of one bank of cylinders of the engine is located is set as the Y0 line, and the reference line of the exhaust pipes connected to the exhaust branch pipe arranged at intervals along the Z direction is set as the Z0 line. The Z0 line is set parallel to the Y0 line and the Z0 line is located on the same horizontal plane as the Y0 line. The center of the turbine housing (11) of the turbocharger (10) is set below the Y0 line and the Z0 line, and the axial direction of the turbine of the turbocharger (10) is set along the Y direction. The bearing housing (13) of the turbocharger (10) is set below the Y0 line and the Z0 line. The fixing hole is flush with the Y0 line, the rotation angle of the turbocharger (10) is θ, the distance between the center of the turbine housing (11) and the axis of the turbine inlet (12) of the turbine housing (11) is Z6, the component of the distance between the center of the turbine housing (11) and the axis of the turbine inlet (12) in the Y direction is Z7, Z7=Z6×cosθ, and the Z-direction distance between the center of the outlet flange (51) of the exhaust manifold (50) connected to the turbine inlet (12) and the Z0 line is set as Z5, Z5=Z7; S20. The number of exhaust pipes and the number of exhaust branch pipes connected to each exhaust pipe are set according to the number of cylinders in a row of cylinders of the engine. Expansion joints are respectively provided on the exhaust pipes between adjacent exhaust branch pipes, between the end of the exhaust pipe near the exhaust manifold (50) and the intake branch pipe of the exhaust manifold (50), and between the outlet flange (51) and the inlet flange of the turbine inlet (12). The exhaust pipe is axially arranged along the X direction, and the distance between the axial direction of the exhaust pipe and the Y0 line is Yn. The main support (70) fixedly connected to the exhaust main pipe (50) is set on the Z0 line and the bottom surface of the main support (70) is flush with the Z0 line. The center line of the fixing hole of the main support (70) is flush with the Y0 line. The distance between the center of the inlet flange of the turbine inlet (12) and the Y0 line is Y6, and the distance between the center of the inlet flange of the turbine inlet (12) and the axial direction of the intake branch of the exhaust main pipe (50) is Y5. Yn = Y5 + Y6. S30. Perform thermal coupling calculation on the pulse exhaust system. Based on the results of the thermal coupling calculation, adjust the relative positions of the exhaust pipes in the Y and Z directions on both sides of the expansion joint in step S20, and perform thermal coupling calculation on the adjusted pulse exhaust system to verify the relative positions of the exhaust pipes in the Y and Z directions on both sides of each expansion joint.

2. The pulse exhaust system design method for an engine as described in claim 1, characterized in that, The engine is an inline engine, and a set of pulse exhaust systems is provided for one bank of cylinders of the inline engine.

3. The pulse exhaust system design method for an engine as described in claim 1, characterized in that, The engine is a V-type engine or a W-type engine, and a pulse exhaust system is set for each bank of cylinders.

4. The pulse exhaust system design method for an engine as described in any one of claims 1 to 3, characterized in that, At least two of the exhaust pipes in step S20 are arranged on the same vertical plane and are evenly spaced along the Z direction, with the central axis of the at least two exhaust pipes being flush with the Z0 direction.

5. The pulse exhaust system design method for an engine as described in claim 4, characterized in that, The engine has four or more cylinders in a row, and the number of cylinders is even. The number of exhaust pipes is half the number of cylinders, and each exhaust pipe is connected to two exhaust branch pipes.

6. A pulse exhaust system, corresponding to a bank of cylinders in an engine, comprising a turbocharger (10), an exhaust manifold (50), and at least one exhaust pipe, characterized in that, The exhaust pipe extends axially along the X direction, and at least two exhaust branch pipes are connected to each exhaust pipe. The connecting flanges of the exhaust branch pipes are located on the same straight line Y0. The axial direction of the exhaust pipe is parallel to the Y0 line. The reference line of the exhaust pipes arranged at intervals along the Z direction is set as the Z0 line. The Z0 line is parallel to the Y0 line and the Z0 line is located on the same horizontal plane as the Y0 line. Expansion joints are provided on the exhaust pipe between adjacent exhaust branch pipes, between the end of the exhaust pipe near the exhaust main pipe (50) and the intake branch pipe on the corresponding side of the exhaust main pipe (50), and between the outlet flange (51) of the exhaust main pipe (50) and the inlet flange of the turbine inlet (12) of the turbocharger (10). The turbine housing (11) of the turbocharger (10) is located below the Y0 line. The turbine of the turbocharger (10) is axially arranged along the Y direction. The bearing housing (13) fixing hole of the turbocharger (10) is flush with the Y0 line. The distance between the center of the turbine housing (11) and the axis of the turbine inlet (12) in the Y direction is Z7, Z7 = Z6 × cosθ, where θ is the rotation angle of the turbocharger (10), Z6 is the distance between the center of the turbine housing (11) and the axis of the turbine inlet (12), and the Z-direction distance between the center of the outlet flange (51) of the exhaust manifold (50) and the Z0 line is Z5, Z5 = Z7.

7. The pulse exhaust system as described in claim 6, characterized in that, The engine is an inline engine, the number of cylinders of the inline engine is greater than or equal to four and the number of cylinders of the inline engine is an even number, the number of exhaust pipes is half the number of cylinders, and the exhaust pipes are arranged at intervals along the Z direction.

8. The pulse exhaust system as described in claim 7, characterized in that, Each exhaust pipe is connected to two exhaust branch pipes. One exhaust branch pipe is connected to the end of the exhaust pipe away from the exhaust main pipe (50), and the other exhaust branch pipe is connected to the end of the exhaust pipe near the exhaust main pipe (50). The expansion joint connected in series on the exhaust pipe between the two exhaust branch pipes is a middle expansion joint. The expansion joint between the end of the exhaust pipe near the exhaust main pipe (50) and the intake branch pipe of the exhaust main pipe (50) is an end expansion joint.

9. The pulse exhaust system as described in claim 8, characterized in that, At least two exhaust pipes are arranged in the same vertical plane and are evenly spaced along the vertical direction, and the central axis of at least two exhaust pipes is flush with the Z0 direction.

10. The pulse exhaust system as described in claim 8, characterized in that, At least two of the exhaust pipes are provided with corresponding central expansion joints, and at least two of the exhaust pipes are provided with corresponding end expansion joints between the exhaust pipes and the intake branch pipes of the exhaust main pipe (50).

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