JPH0622112Y2 - Exhaust manifold - Google Patents

Description

TECHNICAL FIELD The present invention relates to an exhaust manifold of an internal combustion engine such as an automobile, and more particularly to an exhaust manifold in which rigidity of a manifold flange is improved to prevent gas leakage.

(Prior Art) Generally, an exhaust manifold of an internal combustion engine is fixed to a cylinder head and is used for discharging exhaust gas inside the cylinder from an exhaust port. In such an exhaust manifold, the temperature of the exhaust manifold becomes high due to the high temperature exhaust gas when the engine is driven, while the exhaust manifold also becomes normal temperature when the engine is stopped, so that thermal expansion and thermal contraction are repeated. For this reason, it is necessary to increase the strength and rigidity of the joint portion, the manifold flange, and the like of the steel pipe that is greatly affected by thermal deformation.

A conventional exhaust manifold of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 56-96113, which is shown in FIGS. In FIG. 6, an exhaust manifold 61 on the left side of the drawing includes an exhaust introducing pipe 62, manifold flanges 64 to 66 arranged at an opening end of the exhaust introducing pipe 62 on the cylinder head 63 side, and a cylinder head 63. The exhaust outlet pipe 67 is connected to the opening end portion on the opposite side. The manifold flanges 64 to 66 fasten the exhaust introduction pipe 62 to the cylinder head 63 with bolts.
As shown in the figure, a steel plate is punched and formed into a flat plate shape. The exhaust manifold 71 on the right side in FIG. 6 has the same configuration as the exhaust manifold 61 on the left side in the figure. Corresponding components are denoted by reference numerals 72, 74 to 77, and detailed description thereof will be omitted. Exhaust gas in a cylinder (not shown) passes through exhaust gas introduction pipes 62 and 72 provided in a cylinder head 63 and is exhausted from exhaust gas exhaust pipes 67 and 77. At this time, the exhaust manifold repeatedly undergoes thermal expansion and contraction due to the temperature difference between the temperature in the state of being raised by the high-temperature exhaust gas and the temperature when the engine is stopped, and pressure and tension are repeatedly applied to the manifold flange.

(Problems to be solved by the invention) However, in such a conventional exhaust manifold, since the manifold flange has a flat plate shape formed by punching out a steel plate, the manifold flange is also deformed due to thermal deformation of the exhaust introduction pipe. It was easy. That is, due to thermal expansion and contraction of the exhaust introduction pipe, pressure and tension are repeatedly applied to the manifold flanges at the open ends of both ends of the exhaust introduction pipe repeatedly, and the manifold flange is warped to reduce the sealing surface pressure with the cylinder head. There was a problem that gas leakage occurred.

It should be noted that gas leakage can be prevented by increasing the number of bolts and increasing the flange plate thickness, but the former measure complicates assembly and the latter measure increases heat loss. It causes a defect.

(Purpose of the Invention) Therefore, the present invention improves strength and rigidity by appropriately reinforcing the manifold flange without increasing the number of bolts and increasing the plate thickness, preventing deformation and preventing gas leakage. The purpose is to prevent.

(Means for Solving Problems) The exhaust manifold according to the present invention achieves the above-mentioned object.
At least three or more exhaust ports formed in the cylinder head are connected to at least three exhaust pipes extending in the arrangement direction of the exhaust ports, and at least three or more exhaust pipes for connecting the ends of at least three branch pipes of the collective exhaust pipe. In an exhaust manifold including a manifold flange, a manifold flange located on the outermost side of the manifold flange is provided with a plurality of bolt holes and a rib extending in a direction connecting the bolt holes, and the rib extends. The angle between the direction and the arrangement direction of the exhaust ports is configured to be an acute angle.

(Operation) In the present invention, since ribs are formed between the bolt holes of the manifold flange, the flange rigidity can be increased by the bolts and ribs provided at positions that form an acute angle with respect to the arrangement direction of the exhaust ports. . Therefore, even if the number of bolts for fixing the manifold flange is small, it is possible to prevent deformation of the manifold flange due to thermal strain.
The airtightness between the cylinder head and the exhaust manifold can be maintained.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

1 to 5 are views showing an embodiment of an exhaust manifold according to the present invention.

This embodiment is an example of application to a V-type 6 cylinder engine. First, the configuration will be described. FIG. 1 is a side view showing a state in which one exhaust manifold is attached to one bank. In the figure, 1 is a cylinder head, and the cylinder head 1 is provided with exhaust ports 2 to 4. Exhaust ports 2-4 are connected to respective exhaust introduction ports of a collective exhaust pipe (hereinafter referred to as “collective pipe”) 5 via manifold flanges 6-8, and exhaust the exhaust gas in the cylinder to the collective pipe 5. The manifold flanges 6 to 8 are fixed to the exhaust gas inlet of the collecting pipe 5 by welding, and ribs 9 and 10 are formed as reinforcing members on the outer ends of the manifold flanges 6 to 8 welded to the exhaust gas inlets at both ends. There is. As an example, as shown in detail in FIG. 2, the rib 9 projects rightward in the drawing so that the outer end of the manifold flange 6 is thick, and is formed integrally with the manifold flange 6 by casting or forging. And has sufficient strength as a reinforcing member. On the other hand, since a large stress does not act on the manifold flange 7 welded to the exhaust introduction port at the center of the collecting pipe 5, it is formed by punching a steel plate. An exhaust outlet port is provided on the pipe wall of the collecting pipe 5 on the side facing the cylinder head 1, and an exhaust outlet pipe 11 is connected to the exhaust outlet port. A flange 12 is welded to the other end of the exhaust gas outlet pipe 11 to exhaust the exhaust gas collected in the collecting pipe 5 to the downstream side. Heat collecting plates 13 and 14 are provided on the collecting pipe 5 and the exhaust discharge pipe 11, respectively, to cover the collecting pipe 5 and the exhaust discharge pipe 11 and to be freely slidably joined at the ends. Further, the heat shield plates 15 and 1 so as to cover the flange 12.
6 is provided and is fixed to the flange 12 by bolting.

Next, the operation will be described.

When the engine is driven, the exhaust gas in the cylinder (not shown) is exhausted from the exhaust port 2-4 provided in the cylinder head 1 through the collecting pipe 5 and the exhaust outlet pipe 11. At this time, the temperature of the collecting pipe 5 rises due to the passage of the hot exhaust gas. On the other hand, when the engine is stopped, the collecting pipe 5 also has a normal temperature.
Therefore, the collecting pipe 5 repeats thermal expansion and contraction. At this time, the both ends of the collecting pipe 5 are particularly greatly deformed, and pressure and tension are repeatedly applied to the manifold flanges 6 and 8 located at both ends. Therefore, in this embodiment, since the ribs 9 and 10 are integrally formed on the manifold flanges 6 and 8 by casting or forging, respectively, the strength and rigidity of the manifold flanges 6 and 8 are increased, deformation is suppressed, and sealing surface pressure is reduced. Gas leakage is prevented without lowering. On the other hand, the manifold flange 7 located at the center of the collecting pipe 5 is close to the neutral axis when the collecting pipe 5 is deformed, and the action of pressure and tension is small. And we are trying to reduce the cost.

In this embodiment, ribs 9 and 10 are provided only on the outer ends of the manifold flanges 6 and 8 to reduce the weight.
By changing the number and shape of the ribs 9 and 10, it is of course possible to obtain the required strength and rigidity.

Strength and rigidity are improved, deformation is prevented and gas leakage is prevented. In this case as well, it is of course possible to obtain the required strength and rigidity by enlarging and reducing the thick portion 21.

In FIG. 4, heat shield plates 34 to 37 are attached so as to cover a collective exhaust pipe (hereinafter, “collector pipe” 31) exhaust outlet pipe 32 having an exhaust introduction portion and a flange 33. Ribs 38 and 39 provided on the outer periphery of the heat shield plates 34 and 35 are fixed by bolts or the like, and the collecting pipe 3
There is a space between it and 1. The heat shield plates 33, 34 are connected at a joint portion 43 between the manifold flanges 6 to 8 on the side closer to the exhaust lead-out pipe 32, and at the joint portion 43, as shown in FIG. A heat shield plate 34 is slidably fitted on the surface and connected. Further, as shown in FIG. 6, the end portion of the heat shield plate 34 is also connected to the exhaust outlet pipe 32 at the opening end portion of the exhaust outlet pipe 32.
It is fixed so that it can slide freely until it comes in contact with the outer peripheral surface. The end of the heat shield plate 34 is similarly fixed at the open end of the collecting pipe 31. Further, the heat shield plates 36, 37 are fastened to the flange 33 with bolts 44 and are prevented from coming into contact with the flange 33 except near the bolt holes. further,
As shown in FIG. 6, an emboss 46 is provided to avoid engagement with the stud 45 that fixes the flange 33.

With such a configuration, in such an exhaust manifold, the contact portion between the collecting pipe 31, the exhaust outlet pipe 32 and the heat shield plates 34, 35 is only the throttle portion at the ends of the heat shield plates 34, 35. Since the contact portion between the flange 33 and the heat shield plates 36 and 37 is only near the bolt 44, the temperature rise of the heat shield plates 34 to 37 is suppressed. Also,
Since the fixing portion and the joint portion 43 are slidable by narrowing the end portions of the heat shield plates 34, 35, the thermal deformation of the collecting pipe 31 is absorbed, and the joint portion 43 is divided into two parts for attachment and detachment. Will be easier. Further, since the ribs 38, 39 at the outer ends are fixed by bolts, it is not necessary to provide a boss or the like on the collecting pipe 31, so that the number of steps is reduced and the weight and cost are reduced. Further, since the bolts for fastening the manifold flanges 40 to 42 and the gasket to the cylinder head 47 are not commonly used for fixing the heat shield plates 34 to 37, loosening of the bolts or the like is prevented.

The present embodiment is an example of application to a V-type 6-cylinder engine, but the present invention is not limited to this. In-line 4 cylinder, 6
Of course, it can be applied to other engines such as cylinders.

(Effect) According to the present invention, since the manifold flange is provided with a predetermined reinforcing member, the strength and rigidity of the manifold flange can be improved, deformation of the manifold flange can be prevented, and the seal between the cylinder head and the cylinder head can be prevented. The surface pressure does not decrease, and gas leakage can be prevented.

[Brief description of drawings]

1 to 5 are views showing an embodiment of an exhaust manifold according to the present invention. FIG. 1 is a side view of the exhaust manifold, and FIG. 2 is a sectional view taken along the line II 'of FIG. Figure 3 shows
A plan view thereof, FIG. 4 is a detailed view of a joint view of a heat shield plate, FIG. 5 is a sectional view taken along the line II-II ′ of FIG. 3, and FIGS. 6 and 7 show a conventional exhaust manifold. FIG. 6 is a side view thereof, and FIG. 7 is a sectional view taken along the line III-III ′ of FIG. 1 ... Cylinder head, 2-4 ... Exhaust port, 5 ... Collecting exhaust pipe (collecting pipe), 6-8 ... Manifold flange, 9, 10 ... Rib, 21 ... Thick part.

Claims (1)

[Scope of utility model registration request] 1. At least three holes formed in a cylinder head.
An exhaust manifold having at least three manifold flanges for connecting to each of at least three exhaust ports each tip of at least three branch pipes of a collective exhaust pipe extending in the arrangement direction of the exhaust ports, A manifold flange located on the outermost side of the manifold flange is provided with a plurality of bolt holes and a rib extending in a direction connecting the bolt holes, and an extending direction of the rib and an arrangement direction of the exhaust ports. The exhaust manifold is characterized in that the angle formed by is an acute angle.