Engine insulator

Abstract

To increase rigidity and improve performance of a fastening work in an insulator covering an exhaust manifold.SOLUTION: An insulator 8 comprises: a first portion 21 forming a shell structure comprising an upper surface part 21a and wall parts 21b-21d; a second portion 22 erecting from a base end of the upper surface part 21a of the first portion 21; and a third portion 23 extended from an upper end of the second portion 22 to a cylinder head 2 side. Since the upper surface part 21a, the second portion 22 and the third portion 23 continue in a step-like manner, they are reinforced with each other, so as to drastically improve rigidity of the insulator 8. Both right and left end parts of the second portion 22 and the tip wall part 21c of the first portion 21 are fastened to each other. Since all of these parts have an approximately vertical posture, stud bolts that are long in right and left directions can be used as fastening means, and a fastening work can be performed without changing postures by using one type of a wrench.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a heat insulation insulator disposed on the exhaust side of an engine for an automobile or the like.

Background Art

[0002] The exhaust gas of the engine is discharged from the exhaust manifold. Since the exhaust manifold becomes hot, it is often heat-insulated by an insulator made of a metal plate. This insulator is in a form that covers the exhaust manifold. However, since the exhaust manifold bends from the cylinder head in a lateral direction and then downward, the insulator also has an upper surface portion that covers the exhaust manifold from above and a wall portion that covers it from the side (outer peripheral direction), and has a shell structure as disclosed in Patent Documents 1 and 2.

[0003] And generally, the upper surface portion and the wall portion of the insulator are each fixed to the exhaust manifold with bolts. For this reason, the exhaust manifold is provided with a bracket portion for fixing the insulator.

[0004] Now, on the exhaust side surface of the cylinder head, a land portion (boss portion) to which the exhaust manifold is fixed is formed in a state of being long in the crankshaft axis direction, and an exhaust port opens in the land portion. However, above the land portion, there may be a concave portion that is recessed inward due to the relationship with the exhaust port, the water jacket, etc.

[0005] Therefore, in Patent Document 1, regarding the insulator for an automobile engine, an extension portion that enters the concave portion of the cylinder head is provided on the upper surface portion of the insulator, and the traveling wind is taken into the space surrounded by the insulator using this extension portion. With such a configuration, there are advantages that the cooling performance of the insulator and the exhaust manifold can be improved, and the durability of the insulator can also be improved.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The insulator has a shell-like three-dimensional shape that wraps around the exhaust manifold and thus has appropriate rigidity. However, particularly the upper surface portion has a large area and is prone to film vibration. Therefore, it can be said that measures for further increasing rigidity are required. Also, it can be said that there is a requirement for improving workability during assembly.

[0008] The present invention aims to disclose a technology that meets such requirements.

Means for Solving the Problems

[0009] The present invention is A plurality of branch pipes arranged in the crankshaft axis direction are collected into one collecting pipe directed to an insulator that blocks heat radiated from the exhaust manifold, and this insulator "has an upper surface portion and a Downward part continuous therewith and From above and laterally covers the exhaust manifold with a first portion, a second portion rising from the proximal edge close to the cylinder head in the first portion, and a third portion extending from the upper end of the second portion toward the cylinder head, Both ends of the second part and the third part facing in the crankshaft axis direction are formed as upward protrusions, and the upward protrusion of the second part serves as an upper fastening part fixed to the exhaust manifold or the cylinder head. In the second part and the third part, the part between the two upward protrusions is a valley part continuous in the crankshaft axis direction. On the other hand One lower fastening part fixed to the collecting pipe of the exhaust manifold is formed at the lower end of the first part A pair of second side walls continuous with both ends of the third part are formed in the second part, and a pair of first side walls continuous with the second side walls are formed in the first part, so that the first part, the second part, and the third part together form a shell structure and has such a configuration.

[0010] The present invention can be developed in various ways. As an example, in claim 2, " Reinforcing ribs continuous with the upward protrusion of the second part and the upper surface part of the first part are bulged and formed " adopts such a configuration.

Effects of the Invention

[0011] In the insulator of the present invention, the second part and the third part are integrally connected to the upper surface part of the shell-shaped first part that covers the exhaust manifold. Since the upper surface part of the first part, the second part, and the third part are bent in a stepped manner, compared with a simple shell-shaped structure such as those in Patent Documents 1 and 2, the rigidity is significantly increased due to the rib effect. Therefore, a phenomenon in which the upper surface part undergoes membrane vibration due to the vibration of the engine does not occur, and the vibration damping effect can be significantly improved. Accordingly, the noise can also be greatly suppressed.

[0012] Further, since the upper surface part of the first part spreads over the exhaust manifold, the heat rising from the exhaust manifold and the radiant heat directly hit it, resulting in a large heat damage. However, since the second part is in an upward posture and the amount of heat received from the exhaust manifold is small, the influence of heat on the bolts and nuts for fastening is also small. Therefore, there is also an advantage that a decrease in the fastening force due to heat can be suppressed.

[0013] Now, in Patent Documents 1 and 2, the wall part and the upper surface part of the insulator are fastened to the exhaust manifold with bolts. Therefore, the bolts for fastening the wall part are in a horizontally long posture, and the bolts for fastening the upper surface part are in a vertically long posture in the vertical direction. However, when the postures of the bolts are different in this way, the operator has to change the posture of the wrench during the fastening operation, which makes the work troublesome. In addition, stud bolts cannot be used at all fastening locations, and ordinary headed bolts have to be used, so there is a problem of poor workability.

[0014] In contrast, in the present invention, the second part that rises upward from the upper surface part serves as the fastening part. On the other hand, since the location of the lower fastening part is downward, the upper and lower fastening partsIt can be fastened with bolts in a horizontally long posture, so that the operator can perform the fastening work without changing the posture of the wrench. Also, since each bolt has the same posture, all the bolts can be made into stud bolts and fastened by tightening nuts. Therefore, the insulator can be temporarily held on each stud bolt in one touch, and each part can be fastened only with a nut wrench. Accordingly, the workability of fastening the insulator can be greatly improved.

[0015] Also, the present invention The second part and the third part Has a pair of upward protrusions and the valley between them Since the second part and the third part have a more complex shape and the rigidity between the second part and the third part is further increased, the reinforcing effect of the first part by the second part and the third part is further improved, and the rigidity of the entire insulator can be further improved. Furthermore, in the present invention, since the third part is continuous with the side walls (wall parts) of the first part and the second part, the rigidity can be further improved As in claim 2, when the upward protrusion of the second part and the upper surface part of the first part are connected by a reinforcing rib, the bending deformation between the upward protrusion and the upper surface part can be eliminated. Therefore, even with fastening at only three locations, the insulator can be fixed extremely firmly to the exhaust manifold

[0016] Also, when applied to an automobile engine, similar to Patent Document 1, since the running wind can be taken into the space surrounded by the insulator from the location of the Valley part (recess) of the second part, there is also an advantage that the cooling performance of the exhaust manifold and the insulator itself can be improved.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0018] Next, embodiments of the present invention will be described with reference to the drawings. This embodiment is applied to a three-cylinder engine for an automobile. For the sake of convenience, the terms in the front-rear direction are used with respect to the direction, but Of an automobile the forward direction is the front and the reverse direction is the rear. That is, it is the direction seen from the driver. The same applies to the left-right direction. Since the engine is a transverse front-exhaust type, the crankshaft axis direction is the left-right direction. Regarding the engine, the crankshaft axis direction is often called the front-rear direction, but this is different from this direction in this embodiment.

[0019] (1). Description of the structure As shown in FIGS. 1 and 6, the engine includes a cylinder block 1, a cylinder head 2 fixed to the upper surface thereof, and a head cover 3 fixed to the upper surface of the cylinder head 2. As shown in FIG. 3, on the exhaust side surface of the cylinder head 2, a longitudinally long land portion 4 is formed in the left-right direction, and three exhaust ports 5 are arranged side by side and open on the land portion 4. The surface of the land portion 4 is a flat exhaust manifold mounting surface.

[0020] And an exhaust manifold 7 is fixed to the land portion 4 via a gasket 6 (see FIG. 6) made of metal or inorganic material, and the exhaust manifold 7 is covered with an insulator (heat shield plate) 8 made of a metal plate. Although the width direction of the engine is the front-rear direction, as shown in FIG. 2, regarding the front-rear direction (the direction orthogonal to the exhaust side surface), the side closer to the cylinder head 2 is the proximal end side (inner side), and the side farther from the cylinder head 2 is the distal end side (outer side).

[0021] As shown in FIGS. 4 and 5, the exhaust manifold 7 has a flange plate 9 overlapping the gasket 6 and three branch pipes 10a to 10c joined thereto, and the three branch pipes 10a to 10c converge into a single collecting pipe 11, and the upper cone portion of the catalyst case 12 is joined to the collecting pipe 11. As shown in FIG. 6, a reinforcing piece 9a protruding outward is provided on the outer periphery of the flange plate 9.

[0022] As can be understood from FIG. 6, the branch pipes 10a to 10c and the collecting pipe 11 that constitute the exhaust manifold 7 are formed hollow by overlapping two half-divided front and rear plates, and the two plates Formed in are fixed by welding the flange-shaped edge pieces 13. In addition, a boss portion 14 for attaching an O2 sensor is provided at the upper cone portion of the catalyst case 12.

[0023] As can be understood from FIG. 4, the flange plate 9 of the exhaust manifold 7 is fixed to the exhaust side surface of the cylinder head 2 with bolts 15 at a total of five locations, three at the upper part and two at the lower part. Therefore, five boss portions 16 that are flush with the surface of the land portion 4 are formed on the exhaust side surface of the cylinder head 2 so as to protrude in the vertical direction, and tap holes 17 are formed in each boss portion 16.

[0024] For example, as clearly shown in FIG. 6, stud bolts are used as the fastening bolts 15 of the exhaust manifold 7, and the flange plate 9 of the exhaust manifold 7 is fixed to the land portion 4 by nuts 18 screwed onto the stud bolts 15.

[0025] As shown in FIG. 4, each of the branch pipes 10a to 10c that constitute the exhaust manifold 7 protrudes outward from the cylinder head 2, bends downward, and converges to the collecting pipe 11. In addition, since the collecting pipe 11 is displaced to the rear side of the cylinder head 2, the branch pipe (first branch pipe) 10a located in the front is long, and the branch pipes (second branch pipe) 10b located in the middle and the branch pipe (third branch pipe) 10c located in the rear have the same length.

[0026] Since the exhaust manifold 7 is constituted by the plurality of branch pipes 10a to 10c and the collecting pipe 11, the exhaust manifold 7 has a shape close to a trapezoid in plan view. For this reason, the insulator 8 also has a basic trapezoidal shape close to the exhaust manifold 7.

[0027] More precisely, the insulator 8 basically has an upper surface portion 21a that covers the exhaust manifold 7 from above, and wall portions 21b, 21c, 21d that surround the exhaust manifold 7 in the left - right direction and from the outside. The two together form the first part (main body part) 21 of the shell structure. The reference numeral 21b indicates the right wall portion (Right side wall) and the reference numeral 21c indicates the left wall portion (Left side wall) and the reference numeral 21d indicates the tip wall portion located far from the cylinder head 2. The tip wall part 21d serves as a lower fastening part and is a downward part in a vertical posture. Therefore, the exhaust manifold 7 is covered by the first part 21 from above and in front (laterally)

[0028] The upper surface portion 21a is curved so as to become lower as it moves away from the cylinder head 2 and is continuous with the tip wall portion 21d. Therefore, the boundary between the upper surface portion 21a and the tip wall portion 21d is ambiguous. Exactly speaking, the portion of the insulator 8 visible in plan view is a curved portion that becomes lower as it moves away from the cylinder head 2.

[0029] From the proximal end of the upper surface portion 21a close to the cylinder head 2, a second part 22 is raised upward, and a third part 23 extends from the upper end of the second part 22 toward the cylinder head 2. The third part 23 has substantially the same width over its entire length.

[0030] The second part 22 of the insulator 8 has Serves as an upper fastening part horn - shaped upward protrusions 22a Have at both the left and right ends, and between the left and right upward protrusions 22a is Longitudinal left and right a concave portion (valley portion) 22b. Therefore, the third part 23 also follows the form of the second part 22, with the left and right ends being the upper - stage portions 23a and the portion therebetween being Lower longitudinal part (valley part) 23b. As shown in Fig. 2, at both the left and right ends of the second part 22, there are Side wall 22c connected to the left and right wall portions 21b, 21c in the first part 21 and the left and right ends of the third part 23

[0031] The insulator 8 is fixed to the exhaust manifold 7 at three locations: the left and right upward protrusions 22a provided on the second portion 22, and the tip wall portion 21d constituting the first portion 21. As can be clearly seen from Fig. 5, first, a main body side bracket 24 is fixed by welding to the upper left and right ends of the flange plate 9 of the exhaust manifold 7, the main body side bracket 24 being inclined so as to shift outward to the left and right as it goes upward.

[0032] Furthermore, a pedestal-shaped tip side bracket 25 is fixed by welding to the outer surface of the collecting pipe 11 of the exhaust manifold 7, and a stud bolt 26 is provided protruding laterally from these brackets 24, 25, and the upward protrusion 22a of the second portion 22 of the insulator 8 and the tip wall portion 21d of the first portion 21 are fixed with a nut 27 (see FIG. 1). Therefore, as shown in FIG. 5, a bolt insertion hole 28 is formed in the upward protrusion 22a of the second portion 22 of the insulator 8 and the tip wall portion 21d of the first portion 21.

[0033] 2 and 5, a pair of left and right reinforcing ribs 29 are formed to bulge outward at a portion of the insulator 8 where the top surface 21a and both left and right ends of the second portion 22 are connected. That is, the reinforcing ribs 29 are formed to straddle both the upward protrusion 22a of the second portion 22 and the top surface 21a. A bulge 30 is also formed at the tip wall 21d, and a bolt insertion hole 28 is formed in the bulge 30. Furthermore, a rectangular bulge 31 is also provided to protrude upward at a portion of the top surface 21a constituting the first portion 21, which is closer to the second portion 22 and slightly toward the front.

[0034] Furthermore, a first ventilation opening 32 long in the left-right direction is provided in a portion of the top surface 21a constituting the first portion 21 near the second portion 22 and toward the right, a second ventilation opening 33 long in the left-right direction is provided in a portion of the top surface 21a near the second portion 22 and toward the left, and a third ventilation opening 34 long in the left-right direction is provided in a portion of the top surface 21a near the tip wall portion 21d and toward the right. Also, a fourth ventilation opening 35 long in the left-right direction is provided in a portion of the tip wall portion 21d located above the bulging portion 30.

[0035] As shown in FIG. 6, the portion of the exhaust side surface of the cylinder head 2 above the land portion 4 is a recessed portion 38 recessed inward, and the upper end is a eaves-like portion 2a protruding outward from the land portion 4. Further, water jackets 36 and 37 are formed above and below the group of exhaust ports 5 on the side of the land portion 4 of the cylinder head 2, sandwiching the group of exhaust ports 5. At the location between adjacent exhaust ports 5, the water jackets 36 and 37 extend to the surface side. Due to such a relationship, a deep portion 38a that enters the inner side of the cylinder head 2 is formed in the recessed portion 38 of the cylinder head 2.

[0036] On the other hand, the proximal end of the third portion 23 of the insulator 8 is arranged to cover the flange plate 9 of the exhaust manifold 7 from above, and a ventilation path (gap) 39 for taking in the running wind toward the recessed portion 38 is formed between the proximal end of the third portion 23 and the cylinder head 2.

[0037] (2). Summary In the present embodiment, since the entire exhaust manifold 7 is covered by the insulator 8 from the front, it is possible to prevent damage to the harness and the like due to the heat of the exhaust manifold 7. Also, during inspection while the engine is running, the safety of people can be improved. Further, there is an advantage that the early temperature rise of the catalyst during cold engine operation can be promoted by suppressing heat dissipation. And up And in the present embodiment, the first portion 21 has a shell structure and has a certain degree of rigidity. However, since the upper surface portion 21a of the first portion 21, the second portion 22, and the third portion 23 are bent in a stepped manner, the rigidity of the insulator 8 is significantly improved.

[0038]

[0039] ​That is, first, since the upper surface portion 21a and the second portion 22 are connected in a bent state, the bending deformation of the upper surface portion 21a in the vertical direction is prevented. Next, since the third portion 23 is connected to the second portion 22 in a bent state, the bending of the second portion 22 in the front-rear direction and the bending of the third portion 23 in the vertical direction are suppressed. As a result, the upper surface portion 21a, the second portion 22, and the third portion 23 are held in a state where they do not bend in either the vertical direction or the front-rear direction.

[0040] Therefore, as a whole, the insulator 8 has a three-dimensional structure that is extremely difficult to bend and deform in any of the vertical, horizontal, and front-rear directions. Thereby, it exhibits extremely high rigidity and can significantly suppress vibration and noise.

[0041] When the left and right upward protrusions 22a are formed on the second portion 22 as in the embodiment, the third portion 23 becomes more difficult to bend and deform in the vertical direction, so the rigidity is further improved. Also, when Side wall 22c is provided at both left and right ends of the second portion 22 and this is made continuous with the third portion 23 and the left and right wall portions 21b, 21c of the first portion 21, the exhaust manifold 7 is in a state where the entire circumference is surrounded by walls, so the rigidity can be further improved. When the upward protrusion 22a of the second portion 22 and the upper surface portion 21a of the first portion 21 are connected by the reinforcing rib 29, the bending deformation between the upward protrusion 22a and the upper surface portion 21a can be eliminated. Therefore, even with fastening at only three locations, the insulator 8 can be fixed extremely firmly to the exhaust manifold 7.

[0042] Furthermore, when the first to fourth ventilation holes 32 to 35 are formed in the insulator 8, in the running state of the automobile, the running wind can be taken in to cool the exhaust manifold 7 and the insulator 8 can be cooled from the inside. In the stopped state, the hot air can be dissipated from the ventilation holes 32 to 35 to suppress the accumulation of heat. Therefore, the excessive temperature rise of the insulator 8 and the exhaust manifold 7 can be prevented and their lifespan can be improved.

[0043] When a ventilation passage 39 is provided between the third part 23 and the cylinder head 2, similar to Patent Document 1, the running wind can be taken into the inside of the insulator 8 by utilizing the recess 38, so that there is an advantage that the cooling performance of the insulator 8 and the exhaust manifold 7 can be further improved.

[0044] In this embodiment, Of the first part 21 the tip wall portion 21d and the second part 22 To the exhaust manifold 7 are fastened, but since these parts are all surfaces that generally extend in the vertical direction, as fastening means Front and back longitudinal stud bolts 26 can be used. Therefore, when fastening the insulator 8, the insulator 8 may be fitted onto the three stud bolts 26 and then the nut 27 may be screwed onto the stud bolts 26. Therefore, it is not necessary to use headed bolts and the fastening work can be performed with one type of wrench, and the insulator 8 can be assembled efficiently because the wrench can be used for fastening while remaining in a horizontal orientation without changing its posture.

[0045] As described above, the embodiments of the present invention have been described, but the present invention can be embodied in various other ways. For example, the exhaust manifold can adopt various forms according to the number of cylinders, the position of the collecting pipe, etc., and accordingly, the form of the insulator can also be various Embodiment changed.

Industrial Applicability

[0047] The present invention can be embodied in an insulator of an engine. Therefore, it can be used industrially.

Explanation of Reference Numerals

[0048] 2 Cylinder head 4 Land portion (exhaust manifold mounting surface) 5 Exhaust port 7 Exhaust manifold 8 Insulator 10a~10c Branch pipes 11 Collecting pipe 21 First part 21a Upper surface portion 21b, 21c Side wall (wall part) of the first part 21d Front wall part of the first part 22 Part 2 22a Upward protrusion 22b Recess (Valley part) 22c Side wall of the second part 23 Part 3 23a Upper section 23b Lower section 24,25 Brackets 15, 26 Stud bolt 18, 27 Nut 29 Reinforcing rib 32 - 35 Ventilation holes 38 Recess of cylinder head 39 Ventilation passage

Claims

An insulator that blocks heat radiated from an exhaust manifold in which a plurality of branch pipes arranged in the crank axis direction are gathered into one collecting pipe, a first portion having an upper surface portion and a downward portion continuous therewith, covering the exhaust manifold from above and laterally; a second portion rising from a proximal edge close to the cylinder head in the first portion; and a third portion extending from the upper end of the second portion toward the cylinder head, wherein both ends in the crank axis direction of the second portion and the third portion are formed as upward protrusions, the upward protrusion of the second portion serves as an upper fastening portion fixed to the exhaust manifold or the cylinder head, and the portion between the two upward protrusions in the second portion and the third portion is a valley portion continuous in the crank axis direction, while one lower fastening portion fixed to the collecting pipe of the exhaust manifold is formed at the lower end of the first portion, a pair of second side walls continuous with both ends of the third portion are formed in the second portion, and a pair of first side walls continuous with the second side walls are formed in the first portion, whereby the first portion, the second portion, and the third portion form a shell structure as a whole, an insulator for an engine. Reinforcing ribs continuous with the upward protrusion of the second portion and the upper surface portion of the first portion are bulged and formed. The engine insulator according to claim 1.

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