JP3899832B2 - Engine exhaust manifold mounting structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an engine exhaust manifold mounting structure for fixing an exhaust manifold to an in-line four-cylinder engine.
[0002]
[Prior art]
  Conventionally, as an exhaust manifold mounting structure of the engine of the above-described example, for example,,There is a structure described in Japanese Utility Model Publication No. 4-91224.
  Ie,In an in-line four-cylinder engine, a total of four steel pipe branch pipes for four cylinders whose upstream ends are connected to the cylinder head of the engine via mounting flanges, and downstream ends of these branch pipes are connected to the inside. A casting assembly having a partition wall, and a boss portion at the lower portion of the cylinder block. The U-shaped engine mounting bracket bolted up to the above-described assembly portion is used to connect the exhaust manifold to the boss portion. It is attached to the part.
[0003]
  The above-described collective portion and the partition wall provided in the collective portion are made of cast metal, and the partition wall has a large wall thickness, so that no noise is generated due to engine vibration.
  However, for the purpose of reducing the weight of the collecting portion, when the casting collecting portion is formed as a steel pipe collecting portion, and a partition plate that bisects the exhaust gas flow is provided inside the collecting portion, The partition plate vibrates due to engine vibration, and noise is generated.
[0004]
  Also,Exhaust manifold support bosses with screw holes are provided in the above-mentioned collective part, and the U-shaped engine mounting brackets are fastened and fixed using bolts that are screwed into the screw holes of the bosses from both sides. Since the engine mounting bracket is attached to the boss portion at the lower part of the cylinder block, even when the exhaust manifold is hot-extended due to the flow of high-temperature exhaust gas, this hot extension cannot be absorbed. there were.
[0005]
[Problems to be solved by the invention]
  In the present invention, a collecting portion connected to the downstream ends of the four branch pipes is provided, and the upstream end of the partition plate is fixed to the connecting portion having high rigidity between the collecting portions and the downstream ends of the branch pipes, and the connection described above. It is possible to further improve the rigidity by providing the engine mounting bracket around the connection part or the connection part, and by separating the partition plate and the engine mounting bracket, the vibration of the engine is transmitted to the partition plate. Suppressing and preventing the generation of noise due to partition vibrationFurther, by inserting a cross-shaped reinforcing plate into the downstream part of the four branch pipes and welding the reinforcing plate and the substantially right-angled outer wall of the downstream part of each branch pipe, the downstream ends of the branch pipes are connected to each other. As a result, there is no gap in the gap, so that the welding strength can be increased, and interference between the downstream portions of the branch pipes can be prevented.The object is to provide an engine exhaust manifold mounting structure.
[0006]
[Means for Solving the Problems]
  An engine exhaust manifold mounting structure according to the present invention is an engine exhaust manifold mounting structure for fixing an exhaust manifold to an in-line four-cylinder engine, and includes four branch pipes whose upstream ends are connected to an engine cylinder head; Connected to the downstream end of each branch pipe and provided with a collecting part having a partition plate inside, exhaust gas from two branch pipes on both sides in the cylinder row direction where the ignition order is not adjacent is introduced by the partition plate. A first collecting portion and a second collecting portion into which exhaust gas from two branch pipes on the center side in the cylinder row direction is introduced. An engine mounting bracket is provided at a position facing the engine on the side of the second collecting portion on the connecting portion between the branch pipes and the collecting portion or around the connecting portion.In the downstream part of the four branch pipes, a curved part in contact with the inner wall upstream of the gathering part and a substantially right angle part located inward of the upstream of the gathering part are formed. A substantially right-angled portion is arranged in close proximity to form a cross-shaped space, a cross-shaped reinforcing plate is inserted into the cross-shaped space, and the reinforcing plate is welded to the outer wall of the substantially right-angled portion at the downstream of each branch pipe. At the same time, a plate constituting one of the cross-shaped reinforcing plates is set to be a partition plate that extends into the assembly portion and bisects the exhaust passage in the assembly portion.Is.
[0007]
  According to the above configurationIfA collecting portion connected to the downstream ends of the four branch pipes is provided, and the upstream end of the partition plate is fixed to the connecting portion having high rigidity between the collecting portions and the downstream ends of the branch pipes. Since the engine mounting bracket is provided around the connecting portion or the connecting portion, the rigidity can be further improved.
[0008]
  furtherSince the partition plate and the engine mounting bracket in the above-described assembly part are arranged apart from each other, it is possible to prevent the vibration of the engine from being transmitted to the partition plate and to prevent the generation of noise due to the vibration of the partition plate.
[0009]
  In addition, since the first collecting portion is disposed on the engine outer side with respect to the second collecting portion, the bent portion of each branch pipe can be set short, and a partition plate is provided inside the collecting portion for exhaust. Since the gas flow passage is divided into two, the gathering portion can be formed compactly, and a compact 4-2-1 type exhaust system can be secured.
[0010]
  Here, the 4-2-1 type exhaust system is one in which exhaust gas flow passages are once divided into two from the four branch pipes and then exhausted through one common flow passage. By gathering, it is difficult to be affected by exhaust gas back pressure and exhaust pulsation.
[0011]
  Moreover, a cross-shaped reinforcing plate is inserted into the downstream part of the four branch pipes, and this reinforcing plate is welded to the substantially right-angled outer wall of each downstream part of the branch pipe, so that there is a gap between the downstream ends of the branch pipes. The weld strength can be increased, and interference between the downstream portions of the branch pipes can be prevented.
In addition, since the plate constituting one of the cross-shaped reinforcing plates, that is, the partition plate extending into the collective portion is also welded and fixed to the collective portion, the rigidity of the connecting portion can be further enhanced..
[0012]
  In one embodiment of the present invention, the engine mounting bracket includes a bracket body and a flange portion substantially orthogonal to the bracket body, and the bracket body and the flange portion are connected via a round portion, The flange portion is connected to the connection portion or the second assembly portion side around the connection portion and a portion facing the engine.
  According to the above configurationIfThe hot extension of the exhaust manifold through which the high-temperature exhaust gas circulates can be mitigated by the aforementioned rounded portion, and the engine vibration can be absorbed by the rounded portion.
[0013]
  In one embodiment of the present invention, the collecting portion is formed in a double tube structure including an inner tube and an outer tube covering the inner tube at a predetermined distance outside the outer periphery of the inner tube, and the inner tube and the outer tube are The engine mounting bracket is connected to the outer pipe on the downstream side of the welding fixing portion while being welded and fixed at the upstream end of the collecting portion.
[0014]
  According to the above configurationIfThe engine mounting bracket is connected to the outer pipe on the downstream side of the above-described weld fixing portion. In short, since the engine mounting bracket is connected to a portion where a gap corresponding to a predetermined distance exists between the inner tube and the outer tube, it is possible to prevent the engine vibration from being transmitted to the inner tube and the partition plate.
  In addition, since the collecting portion has a double tube structure of an inner tube and an outer tube, the heat retention of the exhaust gas is improved, and the catalytic converter interposed in the exhaust system can be activated early.
[0015]
  In one embodiment of the present invention, the collecting portion is formed in a double tube structure including an inner tube and an outer tube covering the inner tube at a predetermined distance outside the outer periphery of the inner tube, and the inner tube and the outer tube are In addition to being welded and fixed at the upstream end of the gathering portion, the engine mounting bracket is connected to the outer pipe of the welding fixing portion.
[0016]
  According to the above configurationIfSince the engine mounting bracket is also connected to the weld fixing part where the inner pipe, outer pipe and branch pipe are fixed by welding, the rigidity and welding strength can be improved, and welding fixing at the same location is sufficient. It is also possible to reduce the number of welding processes.
  Furthermore, since the above-mentioned collecting portion has a double structure of the inner pipe and the outer pipe, the heat retention of the exhaust gas is improved, and the catalytic converter interposed in the exhaust system can be activated early.wear.
[0017]
【Example】
  An embodiment of the present invention will be described in detail with reference to the drawings.
  1 shows an exhaust manifold mounting structure of an engine. In FIG. 1, an in-line four-cylinder engine 11 has a cylinder head cover 14 attached to an upper part of a cylinder block 12 via a cylinder head 13 and an oil oil attached to the lower part of the cylinder block 12. A pan 15 is attached. In the figure, 16 is a crank center, and 17 is a mating surface between the cylinder block 12 and the cylinder head 13.
[0018]
  The in-line four-cylinder engine 11 described above,It is arranged horizontally in the front engine room, and is configured to take in air from the front side of the vehicle body of the engine and exhaust it backward. That is, the exhaust manifold 18 including the branch pipes 24 to 27 and the collecting portion 28, which will be described later, is configured in the rear exhaust structure for the purpose of improving the heat retention of the exhaust gas without being exposed to the traveling wind.
[0019]
  Also,An exhaust pipe 19 is connected to the downstream end of the exhaust manifold 18 described above, the exhaust pipe 19 is led to the lower part of the vehicle body such as the front floor panel 20, and the exhaust pipe 19 has a catalytic converter 21 (so-called catalyst) for purifying exhaust gas. List).
[0020]
  The engine mounting flange 23 of the exhaust manifold 18 is bolted up to the exhaust port outlet end portion (exit end surface) of the cylinder head 13 via the gasket 22 shown in FIGS.
[0021]
  Here, the exhaust manifold 18 includes a total of four branch pipes 24, 25, 26, 27 corresponding to four cylinders as shown in FIGS. 2, 3, and 4, and each of the four cylinders. A collecting portion 28 that is connected to the downstream ends of the branch pipes 24 to 27 to join the exhaust gas, and an upstream end of the exhaust pipe 19 that is disposed on the downstream side of the collecting portion 28 to alleviate roll vibration of the engine 11. An upper insulator 30 and a lower insulator 31 that substantially cover from the engine mounting flange 23 to the downstream end of the collecting portion 28 with respect to the cylinder head 13 at the upstream end of the exhaust manifold 18. It is configured to ensure the heat retention of the exhaust gas and to prevent heat damage to the surroundings.
[0022]
  Also,Of the branch pipes 24 to 27 described above, the branch pipe 24 corresponds to the first cylinder, the branch pipe 25 corresponds to the second cylinder, the branch pipe 26 corresponds to the third cylinder, and the branch pipe 27 corresponds to the fourth cylinder. It corresponds to.
  Further, as shown in FIG. 1, a catalytic converter 21 is disposed in the downstream portion of the above-described collecting portion 28 and in the lower portion of the vehicle body in the vicinity.
[0023]
  Next, the configuration of each branch pipe 24 to 27 will be described in detail with reference to FIGS. 5, 6, and 7 (the drawings in a state where the insulators 30 and 31 including two members are removed). ˜27 are configured by single pipes (single pipes) in consideration of bending workability, and each of the branch pipes 24˜27 is directed from the respective upstream ends toward the center side in the cylinder row direction, and directly downstream thereof. A bent portion 32 (see FIG. 7) bent so that the axial centers (axial cores) of the branch pipes 24 to 27 are obliquely rearward and downward on the side, and downstream of the branch pipes 24 to 27 It is comprised from the linear part 33 (refer FIG. 7) extended linearly to the gathering part 28 arrange | positioned at the side.
[0024]
  Also,The branch pipe 24 corresponding to the first cylinder and the branch pipe 27 corresponding to the fourth cylinder are formed to have substantially the same length, the branch pipe 25 corresponding to the second cylinder, and the branch pipe corresponding to the third cylinder. 26 is formed in substantially the same length.
[0025]
  further,At least a part of the connecting portion 28a (see FIG. 9) between each of the branch pipes 24 to 27 and the collecting portion 28 is set to a height on the extension line 17a of the mating surface 17 of the cylinder block 12 and the cylinder head 13. In addition, the exhaust gas flow passage from the straight portion 33 of each of the branch pipes 24 to 27 to the downstream end of the collecting portion 28 is configured in a straight line as shown in FIGS.
[0026]
  In addition, the lower end part of the spherical universal joint 29 arrange | positioned downstream of the above-mentioned gathering part 28 is set to the position which adjoins on the extension line 16a of the crank center 16, as shown in FIG.
[0027]
  8 is a view seen from the direction of arrow X in FIG. 7, FIG. 9 is a cross-sectional view taken along line AA in FIG. 8, FIG. 10 is a cross-sectional view taken along line BB in FIG. It is CC sectional view taken on the line, and the above-mentioned gathering part 28 is as follows.,As shown in FIG. 9, a double pipe structure is set, in which an inner pipe 34 through which exhaust gas introduced from each branch pipe 24 to 27 circulates and an outer pipe 35 surrounding the inner pipe 34 with a predetermined distance therebetween. Has been.
[0028]
  The inner tube 34 and the outer tube 35 are made of a heat-resistant metal material and cover the inner tube 34 at a predetermined distance outside the outer periphery of the inner tube 34.3510 and 11 is formed of two members 35a and 35b having a halved structure, and the inner tube 34 and the outer tube 35 described above are welded and fixed at the upstream end of the assembly portion 28, so that a weld fixing portion is formed. α (see FIG. 9) is formed. As this welding means, MIG welding (inert gas arc welding) is used, but it may be joined by laser welding instead of this MIG welding.
[0029]
  Further, as shown in FIGS. 9, 10, and 11, it extends from the upstream end of the above-described collecting portion 28 to the downstream side in the axial direction of the collecting portion 28, and is introduced from each branch pipe 24, 25, 26, 27. A so-called 4-2-1 type exhaust system is configured by providing a heat-resistant metal partition plate 36 that divides the exhaust gas to be bisected and led downstream.
[0030]
  The partition plate 36 allows the inside of the inner pipe 34 in the collecting portion 28 to correspond to the two branch pipes 24 and 27 on both sides in the cylinder row direction where the ignition order is not adjacent (that is, the first cylinder and the fourth cylinder). A first collecting portion 41 that collects exhaust gas introduced from the branch pipe), and the remaining branch pipes, that is, two branch pipes 25 and 26 (that is, the second cylinder) at the center in the cylinder row direction where the ignition order is not adjacent to each other. And a second collecting portion 42 for collecting the exhaust gas introduced from the branch pipes corresponding to the third cylinder).
[0031]
  Since the exhaust gas from the first cylinder and the fourth cylinder is introduced or collected in the first collecting portion 41 described above, the ignition order is the order of # 1 → # 3 → # 4 → # 2 or # 1 → # 2. In any case of the order of # 4 → # 3, the ignition order is not adjacent.
[0032]
  Similarly, since the exhaust gas from the second cylinder and the third cylinder is introduced or collected in the second collecting portion 42 described above, the ignition order is # 1 → # 3 → # 4 → # 2 or # 1. In any case of the order of # 2 → # 4 → # 3, the ignition order is not adjacent.
[0033]
  Also,The direction of the partition plate 36 described above is set so that the first collecting portion 41 is located outside the engine 11, that is, behind the second collecting portion 42.
  further,As shown in FIG. 9, the inner pipe 34 in the above-described collecting portion 28 has a tapered cylindrical shape so that the exhaust gas flow passage is linear and the cross-sectional area of the inner pipe 34 gradually decreases from the upstream side to the downstream side. It is configured.
[0034]
  Next, a connection structure between a total of four branch pipes 24, 25, 26, and 27 and the upstream end of the collecting portion 28 will be described with reference to FIG.
  Each of the above-mentioned branch pipes 24 to 27 is formed of a steel pipe (round pipe), and the downstream part of each of the branch pipes 24 to 27 is a curved part 24a, 25a, which is in contact with the inner wall of the inner pipe 34 upstream of the collecting part 28. 26a, 27a and substantially right angle portions 24b, 25b, 26b, 27b located inward of the inner pipe 34 upstream of the collecting portion 28 are formed.
[0035]
  Then, the substantially right-angled portions 24b, 25b, 26b, 27b of the four branch pipes 24 to 27 described above are arranged close to each other as shown in FIG. 10 to form a cross-shaped space portion 37. Two reinforcing plates 36 and 38 are inserted into the space 37 in a cross-shaped manner, and these reinforcing plates 36 and 38 are externally attached to substantially right-angled portions 24b, 25b, 26b and 27b of the downstream portions of the branch pipes 24 to 27 described above. It is fixed by welding.
[0036]
  In addition, the plate 36 constituting one of the above-described cross-shaped reinforcing plates 36, 38 is extended inside the collecting portion 28, and the exhaust passage is connected to the first collecting portion 41 and the second collecting portion inside the collecting portion 28. The partition plate is divided into two parts.
[0037]
  As described above, the right-angle portions 24b, 25b, 26b, 27b are formed in the above-described branch pipes 24-27, and the substantially right-angle portions 24b-27b are combined in a cross shape, and the space portion 37 has a cross-shape. The reinforcing plates 36 and 38 are inserted and fixed by welding to eliminate the gap and improve the rigidity of the connecting portion and the welding strength.
[0038]
  Incidentally, since the exhaust manifold 18 described above needs to be supported by the engine 11, a mounting bracket 43 is provided as shown in FIG.
  The mounting bracket 43 is provided at the connection portion 28 a between the branch pipes 24 to 27 and the collecting portion 28 on the above-described second collecting portion 42 side and at a position facing the engine 11.
[0039]
  Also,As shown in FIG. 9, the mounting bracket 43 includes a bracket main body 43a, a flange portion 43b substantially orthogonal to the bracket main body 43a, and a rounded portion 43c that connects these 43a and 43b. The round portion 43c absorbs the heat extension of the exhaust manifold 18 and reduces the undesired transmission of vibration on the engine 11 side to the exhaust manifold 18.
[0040]
  The inner pipe 34 and the outer pipe 35 described above are welded and fixed at the upstream end of the collecting portion 28. In the embodiment of FIG. 9, the lower end of the flange portion 43b of the mounting bracket 43 is connected to the weld fixing portion α of the inner and outer tubes 34 and 35. Further, it is welded to the outer pipe 35 on the downstream side. That is, the lower end of the flange portion 43 b is welded and fixed to a portion where a gap corresponding to a predetermined distance exists between the inner tube 34 and the outer tube 35.
[0041]
  The mounting bracket 43 welded and fixed to the upstream end of the collective portion 28 in this way is fixed to the engine side bracket 45 using bolts and nuts 44 as shown in FIGS. 1 and 2, and this engine side bracket. 45 is attached to a predetermined portion of the cylinder block 12 as shown in FIG.
[0042]
  On the other hand, the exhaust manifold 18 is provided with brackets 46, 47, 48, 49, 50, 51 for attaching the upper insulator 30 and the lower insulator 31, as shown in FIGS.
[0043]
  One of the brackets 46 to 51 is fixed to the upper surface of the straight portion 33 of the branch pipe 27 by welding and the other one bracket 49 is fixed to the lower surface of the straight portion 33 of the branch pipe 25 by welding.
[0044]
  The remaining four brackets 47, 48, 50, 51 are welded and fixed to the upper and lower surfaces near the upstream and downstream of the outer pipe 35 constituting the assembly portion 28. These brackets 47, 48, 50, 51 are Outer tube as shown in FIG.35The bracket 47, 48, 50, 51 is compacted, the outer tube 35 is prevented from spreading, and the bolts and screws used when the insulators 30, 31 are attached. The tightening amount of the tightening member is increased.
[0045]
  Note that nuts are previously joined to the pipes 27, 25, and 35 on the insulator mounting seats of the brackets 46 to 51 described above, but these nuts are not shown for convenience of illustration.
[0046]
  Also,Among the brackets 46 to 51 described above, the brackets 46, 47, 48 positioned on the upper side are set for mounting the upper insulator 30, and the brackets 49, 50, 51 positioned on the lower side are set for mounting the lower insulator 31. Yes.
[0047]
  Next, the configuration of the engine mounting flange 23 connected to the upstream ends of the branch pipes 24 to 27 and connected to the cylinder head 13 will be described in detail with reference to FIG.
[0048]
  A plurality of bolt holes 23a, 23b, 23c, 23d, 23e, 23f, and 23g are arranged and formed in the engine mounting flange 23 in a substantially staggered manner. However, while securing a tool space such as an impact wrench, the branch pipes 24- For the purpose of setting the 27 straight portions 33 to be long, the bolt holes 23c at positions where the two branch pipes 25 and 26 (branch pipes corresponding to the second cylinder and the third cylinder) in the center in the cylinder row direction are close to each other. Specifically, the center of the upstream ends of the branch pipes 24 to 27 is positioned above the line in the cylinder row direction.
[0049]
  Moreover, the bolt hole 23f located in an edge part among several bolt holes 23a-23g is set to the long hole in consideration of the assembly | attachment property. It should be noted that the number of bolt holes set in the long hole is not limited to one, but may be set in plural.
[0050]
  Next, the support structure of the inner pipe 34 in the downstream portion of the collecting portion 28 will be described with reference to FIG.
  The inner pipe 34 described above is,As shown in FIG. 9, the upstream end thereof is welded and fixed to the outer tube 35. The downstream side of the inner tube 34 is the inner tube due to the difference in thermal expansion between both the tubes 34 and 35. 34 is configured to be allowed to extend in the downstream direction.
[0051]
  For this reason,A spacer 52 made of a stainless steel wire mesh or the like is interposed in a ring-shaped space between the inner tube 34 and the outer tube 35, and a portion where the own weight of the inner tube 34 acts, that is, a lower portion in both the tubes 34 and 35 is provided. The support rigidity of the predetermined portion of the spacer 52 positioned is set so that the support rigidity is larger than the other parts. A part of the spacer 52 is joined to the inner tube 34 or the outer tube 35.
[0052]
  As a means for setting the support rigidity of the predetermined portion to be large, at least one of the material, width, thickness, and density of the spacer 52 may be changed. Further, in the embodiment shown in FIG. 11, the spacer 52 is provided around the entire circumference of the ring-shaped space between the inner tube 34 and the outer tube 35. The spacer 52 is provided in the space. Of course, it may be interposed partially or intermittently.
[0053]
  Next, the configuration of the spherical universal joint 29 provided at the downstream end of the collecting portion 28 will be described with reference to FIGS.
  The spherical universal joint 29 includes a pipe member 53 joined to the outer periphery of the downstream end of the outer pipe 35 of the collecting portion 28, a flange 54 joined to the outer peripheral middle part of the pipe member 53, and an outer peripheral downstream part of the pipe member 53. A joint 55 having a spherical surface portion 55a, a bolt 56, a washer 57, and a nut 58 are provided.
[0054]
  Thus, as shown in FIG. 8, the spherical portion 19 a on the upper end side of the exhaust pipe 19 is brought into contact with the spherical portion 55 a of the spherical universal joint 29, and the flange portion 19 b on the upper end side of the exhaust pipe 19 and the bolt 56 are connected. A structure in which the exhaust pipe 19 is connected to the downstream end of the collecting portion 28 via a spherical universal joint 29 with the spring 59 interposed between the spring retainer portion and the roll vibration of the engine 11 is reduced. It is.
[0055]
  Next, the configuration of the above-described upper insulator 30 will be described with reference to FIGS.
  The upper insulator 30 has a cross-sectional gate shape so as to cover the upper majority portion from the mounting flange 23 to the downstream exhaust pipe 19 connection portion at the upstream end of the exhaust manifold 18 including the branch pipes 24 to 27 and the collecting portion 28. Is formed.
[0056]
  Further, as shown in FIG. 16, the upper insulator 30 is provided with a heat insulating material 62 between a metal outer member 60 such as an aluminum-plated steel plate and an inner member 61. A flange portion 63 is provided.
[0057]
  Further, as shown in FIG. 13, the shape viewed from the plane is formed in a substantially T-shape, and the portion corresponding to the collecting portion 28 is arranged in a lateral direction substantially perpendicular to the flow direction of the exhaust gas and outside. A plurality of beads 64, 65, 66 protruding in the direction are integrally formed.
[0058]
  Bolt holes 67, 68, and 69 for attaching the upper insulator 30 to the exhaust manifold 18 are provided at positions where the beads 64, 65, and 66 are formed.
[0059]
  Further, as shown in FIG. 13, bolt holes 70 and 71 for attaching the upper insulator 30 are also provided in portions corresponding to the upstream sides of the branch pipes 24 to 27. One of the bolt holes 71 is set to be a long hole for the purpose of ease of assembling and relaxation of hot extension.
[0060]
  Next, the structure of the lower insulator 31 will be described with reference to FIGS.
  The lower insulator 31 has a concave cross section so as to cover the lower half of the upstream end of the exhaust manifold 18 including the branch pipes 24 to 27 and the collecting portion 28 from the mounting flange 23 to the downstream exhaust pipe 19 connection. Is formed.
[0061]
  Further, as shown in the cross-sectional structure of FIG. 20, the lower insulator 31 has a heat insulating material 74 interposed between a metal outer member 72 such as an aluminum-plated steel plate and an inner member 73. A flange portion 75 is provided.
[0062]
  Further, as shown in FIG. 17, the shape viewed from the plane is formed in a substantially T shape, and the portion corresponding to the collecting portion 28 is in a lateral direction substantially orthogonal to the flow direction of the exhaust gas and outward. A plurality of beads 76, 77, 78 projecting toward the bottom are integrally formed.
[0063]
  Bolt holes 79, 80, 81 for attaching the lower insulator 31 to the exhaust manifold 18 are provided at the positions where the beads 76, 77, 78 are formed.
[0064]
  Also,As shown in FIG. 17, bolt holes 82 and 83 for attaching the lower insulator 31 are also provided in portions corresponding to the upstream sides of the branch pipes 24 to 27, and among these bolt holes 82 and 83, One bolt hole 83 is set to be a long hole for the purpose of ease of assembly and relaxation of hot elongation.
[0065]
  Further, an opening 84 is formed between the beads 76 and 77 to lead out the mounting bracket 43 to the outside.
[0066]
  By the way, as shown in FIG. 6, between the branch pipes 24 and 25 and between the branch pipes 26 and 27 in the engine mounting flange 23 described above, attachment portions 85a, 85b, 86a, Mounting brackets 85 and 86 having 86b are joined and fixed.
[0067]
  The two bolt holes 70 and 71 on the upstream side of the upper insulator 30 are bolted up to the mounting portions 85a and 86a, and the three bolt holes 67, 68 and 69 on the downstream side are brackets 46, 47 and 48 (FIG. 6). Bolted up).
[0068]
  Also, the two upstream bolt holes 82, 83 on the lower insulator 31 side are bolted up to the mounting portions 85b, 86b, and the three downstream bolt holes 79, 80, 81 are brackets 49, 50, 51 (FIG. 7). Bolted up).
  Next, the configuration of the gasket 22 disposed between the cylinder head 13 and the engine mounting flange 23 will be described with reference to FIGS.
[0069]
  The gasket 22 is formed in a double structure of a first member 87 formed of a metal plate such as stainless steel and a second member 88 formed of a metal plate such as steel plate, as shown in FIG. In addition, as shown in FIG. 21, it has openings 89, 90, 91, 92 corresponding to the exhaust port outlet end on the engine 11 side.
  The gasket 22 is formed with bolt holes 22a to 22g that coincide with the bolt holes 23a to 23g of the engine mounting flange 23 shown in FIG.
[0070]
  In addition, after the second member 88 is extended upward, it is bent in the rear direction from the bending point 93, that is, bent in the direction away from the engine 11 in the rearward direction, so that the eaves-shaped guide portion 94 is integrally formed. In addition, a plurality of reinforcing beads 95... Are formed in a predetermined portion between the guide portion 94 and the single structure portion only of the second member 88.
[0071]
  The above-described guide portion 94 guides heat released to the outside from between the insulators 30 and 31 and the exhaust manifold in a direction away from the engine 11. By configuring in this way, the cylinder head 13 of the engine 11. And the cylinder head cover 14 and the engine accessories are configured to prevent thermal deterioration.
[0072]
  Incidentally, as shown in FIG. 2, the upper insulator 30 and the lower insulator 31 are covered so that the lower end of the upper insulator 30 overlaps with the upper end of the lower insulator 31 by a predetermined amount. The gap below is set to be as small as possible.
[0073]
  Further, under the state where both of these 30 and 31 are attached, at least the end of the insulators 30 and 31 on the side of the mounting flange 23 has a predetermined amount of gap L downstream from the flange 23 as shown in FIG. The heat released from the gap L between the engine mounting flange 23 and the insulators 30 and 31 is guided by the guide portion 94 of the gasket 22 and guided away from the engine 11. It is configured to be.
[0074]
  Further, the size of the gap L is set so as to be larger than the gap formed by overlapping the upper insulator 30 and the lower insulator 31 in an overlapping manner. The heat escape from the surface is suppressed and heat is released from the gap L described above.
[0075]
  in this way,The engine exhaust manifold mounting structure of the embodiment shown in FIGS. 1 to 22 is an engine exhaust manifold mounting structure in which the exhaust manifold 18 is fixed to the in-line four-cylinder engine 11, and the upstream end is the cylinder head 13 of the engine 11. Are connected to the downstream ends of the branch pipes 24 to 27, and an assembly portion 28 having a partition plate 36 inside is provided. The ignition order is determined by the partition plate 36. A first collecting portion 41 into which exhaust gas from two branch pipes (see branch pipe 24 corresponding to the first cylinder and branch pipe 27 corresponding to the second cylinder) on both sides in the cylinder row direction that are not adjacent to each other is introduced. And a second collecting portion 42 into which exhaust gas is introduced from two branch pipes (refer to the branch pipe 25 corresponding to the second cylinder and the branch pipe 26 corresponding to the third cylinder) on the center side in the cylinder row direction, The partition plate 36 is formed of the first collecting portion 4. 1 is set in a direction located outside the engine 11 with respect to the second collecting portion 42, and the connecting portion 28 a between the branch pipes 24 to 27 and the collecting portion 28 or the second collecting portion 42 side around the connecting portion. In addition, a mounting bracket 43 is provided at a portion facing the engine 11.
[0076]
  As described above, the collecting portion 28 connected to the downstream ends of the four branch pipes 24 to 27 is provided, and the above-described connecting portion 28 and the connecting portion 28a having high rigidity at the downstream ends of the branch pipes 24 to 27 are described above. Since the upstream end of the partition plate 36 is fixed and the mounting bracket 43 is provided around the connecting portion 28a or the connecting portion, the rigidity can be further improved.
[0077]
  In addition, since the partition plate 36 and the mounting bracket 43 in the above-described assembly portion 28 are spaced apart from each other, the vibration of the engine 11 is prevented from being transmitted to the partition plate 36, and noise is generated due to the vibration of the partition plate 36. Can be prevented.
[0078]
  Further, since the first collecting portion 41 is arranged on the outer side of the engine 11 with respect to the second collecting portion 42, the bent portions 32 (see FIG. 7) of the branch pipes 24 to 27 can be set short. Further, since the partition plate 36 is provided inside the collecting portion 28 to divide the exhaust gas flow path into two, the collecting portion 28 can be formed compactly, and a compact 4-2-1 type exhaust system is secured. be able to.
[0079]
  Here, the 4-2-1 type exhaust system is one in which exhaust gas flow passages are once divided into two from the four branch pipes and then exhausted through one common flow passage. By gathering, it is difficult to be affected by exhaust gas back pressure and exhaust pulsation.
[0080]
  Further, as shown in FIG. 9, the mounting bracket 43 has a bracket main body 43a and a flange portion 43b substantially orthogonal to the bracket main body 43a. The bracket main body 43a and the flange portion 43b have a rounded portion 43c. The flange portion 43b is connected to a portion facing the engine 11 on the second collecting portion 42 side around the connection portion or the connection portion.
  According to this configuration, the thermal expansion of the exhaust manifold 18 through which the high-temperature exhaust gas flows can be mitigated by the above-described round portion 43c, and engine vibration can be absorbed by the round portion 43c.
[0081]
  In addition, the collecting portion 28 is formed in a double tube structure including an inner tube 34 and an outer tube 35 that covers the inner tube 34 outside a predetermined distance from the outer periphery of the inner tube 34, and the inner tube 34 and the outer tube 35. Is welded and fixed at the upstream end of the assembly portion 28, and the mounting bracket 43 is connected to the outer pipe 35 on the downstream side of the weld fixing portion α (see FIG. 9).
[0082]
  According to this configuration, the mounting bracket 43 is connected to the outer pipe 35 on the downstream side of the above-described weld fixing portion α. In short, since the mounting bracket 43 is connected to a portion where a gap corresponding to a predetermined distance exists between the inner tube 34 and the outer tube 35, it is possible to prevent engine vibration from being transmitted to the inner tube 34 and the partition plate 36. Can do.
  In addition, since the collecting portion 28 has a double tube structure of the inner tube 34 and the outer tube 35, the heat retention of the exhaust gas is improved, and the catalytic converter 21 interposed in the exhaust system is activated early. be able to.
[0083]
  In addition, as shown in FIG. 10, in the downstream part of the four branch pipes 24 to 27, there are curved parts 24 a to 27 a in contact with the inner wall upstream of the collecting part 28, and inward of the collecting part 28 upstream. Substantially right-angled portions 24b to 27b are formed, the substantially right-angled portions 24b to 27b downstream of the four branch pipes 24 to 27 are arranged close to each other to form a cross-shaped space 37, and the cross-shaped portion The cross-shaped reinforcing plates 36 and 38 are inserted into the space 37, the reinforcing plates 36 and 38 are welded to the outer walls of the substantially right-angled portions 24 b to 27 b downstream of the branch pipes 24 to 27, and the cross-shaped reinforcing plates A plate 36 that constitutes one of 36 and 38 extends inside the collecting portion 28 and is set as a partition plate that bisects the exhaust passage in the collecting portion 28.
[0084]
  According to this configuration, the cross-shaped reinforcing plates 36 and 38 are inserted into the downstream portions of the four branch pipes 24 to 27, and the reinforcing plates 36 and 38 and the substantially right angle portions 24b downstream of the branch pipes 24 to 27 are inserted. Since the outer wall of ~ 27b is welded, there is no gap between the downstream ends of the branch pipes 24 to 27, and the welding strength can be increased.
  Further, the plate 36 constituting one of the cross-shaped reinforcing plates 36, 38, that is, the partition plate 36 extending into the collective portion 28 is also welded and fixed to the collective portion 28, so that the rigidity of the connecting portion is further increased. Can do.
[0085]
  As shown in the above-described embodiment, a plurality of branch pipes 24 to 27 connected to the cylinder head 13 of the engine 11 and a set connected to the downstream ends of the branch pipes 24 to 27 to join the exhaust gas. The branch pipes 24 to 27 are set to have a single pipe structure and are directed from the upstream end to the center side in the cylinder row direction, and the axial centers of the branch pipes 24 to 27 on the downstream side thereof. Are formed of a bent portion 32 (see FIG. 7) bent so as to be substantially in the same direction, and a straight portion 33 (see FIG. 7) extending linearly to the collective portion 28 arranged on the downstream side. The section 28 is set to a double pipe structure of an inner pipe 34 through which exhaust gas introduced from the branch pipes 24 to 27 flows and an outer pipe 35 surrounding the inner pipe 34, and the downstream end of the collecting section 28. And the upstream end of the exhaust pipe 19 that is disposed downstream of the collecting portion 28 and supported by the vehicle body Are connected by a spherical joint means (see the spherical universal joint 29), and at least a part of the connecting portion 28a between the branch pipes 24 to 27 and the collecting portion 28 is a mating surface between the cylinder block 12 and the cylinder head 13. When the exhaust gas flow path from the straight portion 33 of the branch pipes 24 to 27 to the downstream end of the collecting portion 28 is configured in a straight line, the height is set to 17 on the extension line 17a. Has the following effects.
[0086]
  That is, since the length of the straight portion by both the straight portion 33 in each branch pipe 24 to 27 and the straight shape of the collecting portion 28 can be set long, the exhaust resistance of the exhaust gas is reduced and the engine output is reduced. In addition, the length of the collective portion 28 of the double pipe structure can be set as long as possible to improve the heat retention of exhaust gas in both the inner pipe 34 and the outer pipe 35. Therefore, early activation of the catalytic converter 21 interposed in the exhaust system can be achieved, and further, if each of the branch pipes 24 to 27 described above has a single pipe (single pipe) structure, the bending process is easy. In addition, if the downstream end of the collecting portion 28 and the upstream pipe of the exhaust pipe 19 are connected by spherical joint means (see the spherical universal joint 29), roll vibration of the engine 11 can be reduced.
[0087]
  Further, as shown in the embodiment, when the front intake / rear exhaust structure of the engine 11 is employed, the following effects are obtained.
  That is, since the branch pipes 24 to 27 and the collecting portion 28 are not exposed to the traveling wind by the above-described rear exhaust configuration, the heat retention of the exhaust gas can be further improved, and the branch pipe 24 is more than the front exhaust configuration. 27 The length from the upstream end to the catalytic converter 21 can be shortened.
[0088]
  Further, as shown in the embodiment, an engine mounting flange 23 connected to the upstream end of each of the branch pipes 24 to 27 and connected to the cylinder head 13 is provided, and a bolt hole 23a formed in the engine mounting flange 23 is provided. ˜23 g are arranged in a staggered manner as shown in FIG. 6 and a structure is adopted in which the bolt holes 23 c at positions where the branch pipes 25 and 26 are close to each other are positioned above the cylinder row. Has the following effects.
[0089]
  That is, the bolt hole 23c at a position where the branch pipes 25 and 26 of the engine mounting flange 23 are close to each other is positioned above the cylinder row (a line connecting the center of the upstream end of each branch pipe 24 to 27 in the cylinder row direction). If it does, the straight part of each branch pipe 24-27 can be set still longer, ensuring tool space, such as an impact wrench.
[0090]
  In addition, as shown in the embodiment, when the catalytic converter 21 is disposed on the downstream side of the collecting portion 28 and in the lower part of the vehicle body in the vicinity, the following effects are obtained.
  That is, the catalytic converter 21 can be disposed as close as possible to the collecting portion 28 while omitting a direct catalyst (abbreviated as a catalyst) provided immediately below the exhaust manifold of the front exhaust structure. Early activation of the catalytic converter 21 can be achieved.
[0091]
  Furthermore, as shown in the embodiment, the following effects can be obtained by adopting a configuration in which insulators 30 and 31 that cover at least the outer peripheral portions of the branch pipes 24 to 27 are provided.
  That is, since the outer peripheral parts of the branch pipes 24 to 27 having a single pipe structure having a large heat radiation amount with respect to the collective part 28 having a double pipe structure are covered with the insulators 30 and 31, heat damage to the surroundings by the insulators 30 and 31 In addition, it is possible to improve the heat retention of the exhaust gas at the portions of the branch pipes 24 to 27.
[0092]
  Further, as shown in the above embodiment, the spacer 52 is provided between the inner tube 34 and the outer tube 35 of the collecting portion 28, and the support rigidity of the spacer 52 positioned below the branch tubes 34 and 35 is changed. Adopting a structure that is set large for the part has the following effects.
[0093]
  That is, the spacer 52 can prevent interference due to vibration between the inner tube 34 and the outer tube 35, and in particular, can prevent the lower side of the inner tube 34 to be urged by its own weight from interfering with the outer tube 35. . Further, the extension of the inner tube 34 due to the difference in thermal expansion between the inner tube 34 and the outer tube 35 can be allowed.
[0094]
  FIG. 23 shows another embodiment of the engine exhaust manifold mounting structure, which includes a bracket main body 43a, a flange portion 43b substantially orthogonal to the bracket main body 43a, and a rounded portion 43c that connects both the portions 43a and 43b. The other attachment structure of the attachment bracket 43 is shown.
[0095]
  Also in the embodiment of FIG. 23, the collecting portion 28 has a double-pipe structure comprising an inner tube 34 and an outer tube 35 covering the inner tube 34 at a predetermined distance outside the outer periphery of the inner tube 34, The pipe 34 and the outer pipe 35 are welded and fixed at the upstream end of the assembly portion 28 to form a weld fixing portion α. In this embodiment, the flange portion 43b of the mounting bracket 43 is fixed by welding. It is welded and fixed to the upper end of the outer tube 35 in the part α.
[0096]
  If comprised in this way, since the attachment bracket 43 is also welded to the position where the inner pipe 34, the outer pipe 35, and the branch pipes (in this case, the two branch pipes 25 and 26) are welded, the welding rigidity is further increased. Improvements can be made. Moreover, since welding fixation at the same location is sufficient, the number of welding steps can be reduced compared to the previous embodiment shown in FIG.
[0097]
  Even in this configuration, the other configurations, operations and effects are almost the same as those of the previous embodiment. Therefore, in FIG. 23, the same parts as those in FIG. Omitted.
[0098]
  FIG. 24 shows still another embodiment of the engine exhaust manifold mounting structure. The partition plate 36 that divides the exhaust gas into two in the collecting portion 28 and guides it to the downstream side is further extended to the downstream side. 36 is also disposed in the exhaust pipe 19.
  In addition, the partition plate in the exhaust pipe may be disposed with a predetermined amount of clearance so as not to interfere with the flow, separately from the partition plate of the collecting portion.
[0099]
  With this configuration, the “2” portion of the 4-2-1 type exhaust system can be set longer, and the extension length of the partition plate 36 can be set to meet the demands of the engine. A 2-1 type exhaust system can be configured.
[0100]
  24, since the other configurations, functions and effects are almost the same as those of the previous embodiment, the same reference numerals are given to the same parts in FIG. 24 as in FIG. Detailed description thereof is omitted.
[0101]
  FIG. 25 shows still another embodiment of the engine exhaust manifold mounting structure, and includes an inner pipe 96 through which exhaust gas flows through the exhaust pipe 19 and an outer pipe 97 that covers the outer circumference of the inner pipe 96 by a predetermined distance outside. It is set to a double pipe structure.
  If comprised in this way, since the exhaust pipe 19 of the downstream side also becomes a double pipe structure in addition to the double pipe structure of the gathering part 28, the heat retention of exhaust gas can be improved further.
[0102]
  In the correspondence between the configuration of the present invention and the above-described embodiment,
  The engine mounting bracket of the present invention corresponds to the mounting bracket 43 of the embodiment,
  The present invention is not limited to the configuration of the above-described embodiment.
[0103]
【The invention's effect】
  According to the present invention, the collecting portion connected to the downstream ends of the four branch pipes is provided, and the upstream end of the partition plate is fixed to the connecting portion having high rigidity between the collecting portion and each branch pipe downstream end. By providing an engine mounting bracket around the connection part or around the connection part, the rigidity can be further improved.further,By separating the partition plate and the engine mounting bracket, it is possible to prevent the vibration of the engine from being transmitted to the partition plate and to prevent the generation of noise due to the vibration of the partition plate.In addition, a cross-shaped reinforcing plate is inserted into the downstream part of the four branch pipes, and this reinforcing plate is welded to the substantially right-angled outer wall of each downstream part of the branch pipe. There is no gap in the gap, so that the welding strength can be increased, the interference between the downstream portions of the branch pipes can be prevented, and the plate constituting one of the cross-shaped reinforcing plates, that is, the partition extending into the collecting portion Since the plate is also fixed by welding to the gathering portion, there is an effect that the rigidity of the connecting portion can be further increased.
[Brief description of the drawings]
FIG. 1 is a side view showing an exhaust manifold mounting structure for an engine of the present invention.
FIG. 2 is an enlarged view of a main part of FIG.
FIG. 3 is a front view showing the exhaust manifold as viewed from the rear.
FIG. 4 is an exploded perspective view of an exhaust manifold.
FIG. 5 is a plan view showing a state where an insulator is removed.
FIG. 6 is a front view showing a state where an insulator is removed.
FIG. 7 is a side view showing the state where an insulator is removed.
8 is an explanatory diagram viewed from an arrow X in FIG. 7;
9 is a cross-sectional view taken along line AA in FIG.
10 is a cross-sectional view taken along line BB in FIG.
11 is a cross-sectional view taken along the line CC of FIG.
FIG. 12 is a sectional view of spherical joint means.
FIG. 13 is a plan view of an upper insulator.
FIG. 14 is a front view of an upper insulator.
FIG. 15 is a side view of the upper insulator.
FIG. 16 is a partial cross-sectional view of the upper insulator.
FIG. 17 is a plan view of a lower insulator.
FIG. 18 is a front view of a lower insulator.
FIG. 19 is a side view of the lower insulator.
FIG. 20 is a partial cross-sectional view of a lower insulator.
FIG. 21 is a front view of a gasket.
22 is an enlarged cross-sectional view taken along the line DD in FIG. 21. FIG.
FIG. 23 is a side view showing another embodiment of the engine exhaust manifold mounting structure according to the present invention.
FIG. 24 is a side view showing still another embodiment of the engine exhaust manifold mounting structure according to the present invention.
FIG. 25 is a side view showing still another embodiment of the engine exhaust manifold mounting structure according to the present invention.
[Explanation of symbols]
  11 ... Engine (inline 4-cylinder engine)
  13 ... Cylinder head
  18 ... Exhaust manifold
  24-27 ... Branch pipe
  24a-27a ... Curve
  24b to 27b ... substantially right angle part
  28 ... Meeting part
  28a ... Connection part
  34 ... Inner pipe
  35 ... Outer pipe
  36 ... Partition plate (reinforcement plate)
  37 ... Cross-shaped space
  41 ... 1st collection part
  42. Second assembly part
  43 ... Mounting bracket (Engine mounting bracket)
  43a ... Bracket body
  43b ... Flange
  43c ... Earl Club
  α… Welding fixing part

Claims (4)

An engine exhaust manifold mounting structure for fixing an exhaust manifold to an in-line four-cylinder engine,
Four branch pipes whose upstream ends are connected to the cylinder head of the engine;
Connected to the downstream end of each of the branch pipes, and provided with an assembly having a partition plate inside,
A first collecting portion into which exhaust gas is introduced from two branch pipes on both sides in the cylinder row direction that are not adjacent to each other by the partition plate;
A second collecting part into which exhaust gas from two branch pipes on the center side in the cylinder row direction is introduced,
The partition plate is set in a direction in which the first collecting portion is located outside the engine with respect to the second collecting portion,
An engine mounting bracket is provided at the connection portion between each branch pipe and the collection portion or the second collection portion side around the connection portion, and at a portion facing the engine ,
In the downstream part of the four branch pipes, a curved part in contact with the inner wall upstream of the collecting part and a substantially right angle part located inward of the collecting part upstream are formed,
The substantially right-angled portion of the four branch pipe downstream portions are arranged close to each other to form a cross-shaped space portion,
Insert a cross-shaped reinforcing plate in the cross-shaped space part,
While welding the reinforcing plate to the outer wall of the substantially right-angled portion of the downstream portion of each branch pipe,
An exhaust manifold mounting structure for an engine, in which a plate constituting one of the cross-shaped reinforcing plates is extended to the inside of the collective portion and set to a partition plate that bisects an exhaust passage in the collective portion . The engine mounting bracket has a bracket body and a flange portion substantially orthogonal to the bracket body,
The bracket body and the flange part are connected via a rounded part,
The exhaust manifold mounting structure for an engine according to claim 1, wherein the flange portion is connected to the connecting portion or the second collecting portion side around the connecting portion and a portion facing the engine. The assembly part is formed in a double tube structure including an inner tube and an outer tube that covers the inner tube at a predetermined distance outside the outer periphery of the inner tube,
The inner pipe and the outer pipe are welded and fixed at the upstream end of the collecting portion,
The engine exhaust manifold mounting structure according to claim 1 or 2, wherein the engine mounting bracket is connected to an outer pipe on the downstream side of the weld fixing portion. The assembly part is formed in a double tube structure including an inner tube and an outer tube that covers the inner tube at a predetermined distance outside the outer periphery of the inner tube,
The inner pipe and the outer pipe are welded and fixed at the upstream end of the collecting portion,
The exhaust manifold mounting structure for an engine according to claim 1 or 2, wherein the engine mounting bracket is connected to an outer pipe of a welding fixing portion .

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