JPH0988571A - Division type exhaust manifold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve rigidity of the connecting part of a manifold, to prevent leakage of exhaust gas from the connecting part of a manifold due to vibration, and further to reduce the thermal stress in a longitudinal direction due to vibration to provide an increased life, in a division type exhaust manifold having structure wherein the manifold is divided into a plurality of sections. SOLUTION: A division type exhaust manifold comprises a fit-in part 6 through which the outside diameter 5 of one manifold end part is slidably inserted in the inside diameter 4 of the other manifold end part; and a flexible pipe 3 to which the outer surface of manifold is securely connected. Further, a distance between the end faces of the manifold fit-in part 6 is set to a value slightly higher than a maximum value of a difference between thermal expansion and thermal shrinkage of exhaust manifolds 2 and 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split type exhaust manifold for connecting respective manifolds of an automobile engine, and more particularly to a split type exhaust manifold for preventing leakage of exhaust gas from each manifold connecting portion. .

[0002]

2. Description of the Related Art In a long exhaust manifold of a multi-cylinder engine, the exhaust manifold is divided into two or three sections in order to prevent exhaust gas from leaking due to thermal deformation and thermal cracks caused by repeated engine stoppages. A split type exhaust manifold is used.

[0003] And, for example, the actual exploitation 55-163425
As shown in Japanese Patent Publication No. JP-A-2003-13869, the split exhaust manifolds are connected by fitting the other manifold into one manifold and further forming several grooves in the outer cylinder of the fitting part of the fitting-side manifold. A ring-shaped seal ring is attached, and the surface of the inner cylinder of the manifold on the side where it is fitted is in contact with the outer periphery of the seal ring to prevent leakage of exhaust gas.

However, according to Japanese Utility Model Laid-Open No. 55-163425, due to thermal deformation of the mating surface of the seal ring and the fitting portion of the manifold, a gap is apt to be formed between the inner cylinder of the manifold and the seal ring, and exhaust gas leaks. Cannot be completely prevented.

As a measure against this, Japanese Patent Laid-Open No. 5-2 is known.
In Japanese Patent No. 02745, each manifold connecting portion is connected using a separate inner pipe, a flexible pipe is attached to the outside of the manifold connecting portion, and both ends of the flexible pipe are clamped to the outer periphery of each manifold by using fastening rings. Alternatively, the one fixed by welding is disclosed.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The one disclosed in Japanese Patent No. 745 is excellent in thermal stress and exhaust gas sealability associated with a normal engine shutdown. However, in an engine with a supercharger (also called "turbocharger") and an engine with an exhaust brake, higher-pressure exhaust gas flows and vibrations occur, so the rigidity of the split exhaust manifold connection part is improved. Further improvement is required to prevent exhaust gas leakage from the connecting portion.

The present invention has been made in view of the above circumstances, and an object thereof is to improve rigidity of a connecting portion of a manifold and prevent leakage of exhaust gas from the connecting portion of the manifold due to vibration. Another object of the present invention is to provide a split type exhaust manifold that reduces the thermal stress in the longitudinal direction of the manifold and has a long life.

[0008]

In order to achieve the above object, the present invention provides a split type exhaust manifold having a structure in which a manifold is divided into a plurality of manifolds, one inner diameter of one manifold end being outside the other manifold end. It is characterized in that it has a fitting portion in which the diameter is slidably fitted, and a flexible pipe that covers the fitting portion and connects and fixes the outer surface of each manifold. Then, the outer surface of each manifold fitting portion and the flexible pipe are connected and fixed by welding, or the convex portion or the concave portion formed on the outer surface of each manifold is engaged with the concave portion or the convex portion provided at both ends of the flexible pipe to make flexible. The fastening member straddles the outside of the concave or convex portion of the pipe. Further, the end face spacing of the manifold fitting portion is set to be slightly larger than the maximum value of the difference between the thermal expansion and thermal contraction of the exhaust manifold.

[0009]

The fitting portion at the end of each manifold has an appropriate thickness to improve and secure the rigidity of the exhaust manifold. In addition, the fitting portion enables the entire exhaust manifold to move relative to each other even if the exhaust manifold thermally expands and contracts. Further, the fitting portion primarily prevents the exhaust gas from leaking. The flexible pipe that covers the fitting portion and connects and fixes the outer surfaces of the manifolds prevents the exhaust gas slightly flowing out from the fitting portion from leaking. The distance between the end faces of the manifold fitting portion reduces the thermal stress in the longitudinal direction of the exhaust manifold to extend the life of the exhaust manifold.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to the embodiments shown in FIGS. (Embodiment 1) FIG. 1 is a plan sectional view of a connecting portion 12 of a split type exhaust manifold 1 applied to an inline 6-cylinder gasoline engine with a supercharger mounted on an automobile of an embodiment. In this exhaust manifold 1, exhaust gas discharged from each cylinder of the engine is exhausted from a communication passage 10 of one manifold 2 to a communication passage 1 of another manifold 3 in a direction of an arrow.
1 to a supercharger (not shown). Here, the inner diameter 4 of the end portion larger than the communication passage 11 is formed in one manifold 3, and the communication passage 1 is formed in the other manifold 2.
An end outer diameter 5 larger than 0 is formed as a fitting portion 6 so that the end inner diameter 4 and the end outer diameter 5 can freely slide. Secures an appropriate thickness. Then, the outer surfaces 7, 8 of the respective manifolds 2, 3
The flexible pipe 9 is welded all around. Further, the end face distance L of the fitting portions 6 of the manifolds 2 and 3 is set to be slightly larger than the maximum value of the difference between the thermal expansion and thermal contraction of the exhaust manifold 1.

According to the above, the inner diameter 4 at the end and the outer diameter 5 at the end
Has an appropriate thickness, the rigidity of the connecting portion 12 of the exhaust manifold 1 is improved. And the connecting portion 12
Since the rigidity of the exhaust manifold 1 is improved, thermal deformation of the entire exhaust manifold 1 is small, and even if the exhaust manifold 1 thermally expands and contracts, the fitting portion 6 can be reliably slid. Further, the fitting portion 6 primarily prevents leakage of exhaust gas even if vibration is increased by the supercharger. Further, the flexible pipe 9 that connects and fixes the outer surfaces 7 and 8 of the manifolds 2 and 3 prevents the exhaust gas slightly flowing out from the fitting portion 6 from leaking. The end face spacing L reduces the thermal stress in the longitudinal direction of the exhaust manifold 1 and extends the life of the exhaust manifold 1.

(Embodiment 2) FIG. 2 is a plan sectional view of a connecting portion of a split type exhaust manifold applied to a gasoline engine with an in-line 6-cylinder supercharger mounted on an automobile of another embodiment. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals. An end inner diameter 4 larger than the communication passage 10 is formed in one manifold 2, and an end outer diameter 5 larger than the communication passage 11 is formed in the other manifold 3 to form a fitting portion 6, which is the end inner diameter 4 The outer diameter 5 of the end portion is allowed to slide freely. A flexible pipe 9 is welded to the outer surfaces 7 and 8 of the manifolds 2 and 3 all around. In order to prevent the inner diameter of the flexible pipe 9 from interfering with the outer surfaces 7 and 8, the outer diameter is made smaller than the outer surfaces 7 and 8, and the end inner diameter 4 and the end outer diameter 5 have appropriate wall thicknesses. 16, 17
And Further, the end surface distance L of the fitting portions 6 of the manifolds 2 and 3 is set to be slightly larger than the maximum value of the difference between the thermal expansion and the thermal contraction of the exhaust manifold. With the above configuration, the same effect as that of the first embodiment can be obtained.

(Embodiment 3) FIG. 3 is a plan sectional view of a connecting portion 12 of a split type exhaust manifold 1 applied to an in-line 6-cylinder gasoline engine with a supercharger mounted on an automobile of another embodiment. FIG. 4 is a cross-sectional view showing connection and fixation of the outer surface of each manifold and the flexible pipe, and FIG. 5 is a side view showing a fastening member of the flexible pipe. 2, the same components as those in FIG. 1 are designated by the same reference numerals. In the exhaust manifold 1, the exhaust gas discharged from each cylinder of the engine is discharged from the communication passage 10 of one manifold 2 to the communication passage 1 of another manifold 3 in the direction of the arrow, as in FIG.
1 to a supercharger (not shown). Here, an end inner diameter 4 larger than the communication passage 10 is formed in one manifold 2, and the communication passage 1 is formed in the other manifold 3.
An end outer diameter 5 larger than 1 is formed as a fitting portion 6 so that the end inner diameter 4 and the end outer diameter 5 can freely slide,
The wall thicknesses of the end inner diameter 4 and the end outer diameter 5 are appropriately secured.

Then, as shown in FIG. 4, the concave portions 14 formed at both ends of the flexible pipe 9 are engaged with the convex portions 13 formed on the outer surfaces 7 and 8 of the manifolds 2 and 3, respectively. The fastening member 15 shown in FIG. 5 is fixed across the outside. Further, the end face distance L of the fitting portions 6 of the manifolds 2 and 3 is set to be slightly larger than the maximum value of the difference between the thermal expansion and thermal contraction of the exhaust manifold 1.

[0015]

As described above, in the split type exhaust manifold of the present invention, the fitting portion in which one manifold end inner diameter and the other manifold end outer diameter are slidably inserted, and the fitting portion. Since the structure has a flexible pipe for covering and fixing the outer surface of each manifold, the rigidity of the exhaust manifold is improved, and leakage of exhaust gas can be prevented even if vibration is increased by the supercharger. Also,
Due to the distance between the end faces of the manifold fitting portion, the thermal stress in the longitudinal direction of the exhaust manifold is reduced and the exhaust manifold has a long life.

[Brief description of drawings]

FIG. 1 is a plan sectional view of a connecting portion of a split type exhaust manifold according to an embodiment of the present invention.

FIG. 2 is a plan sectional view of a connecting portion of a split type exhaust manifold according to another embodiment of the present invention.

FIG. 3 is a plan sectional view of a connecting portion of a split type exhaust manifold according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing connection and fixation of an outer surface of each manifold and a flexible pipe.

FIG. 5 is a side view of a fastening member of a flexible pipe.

[Explanation of symbols]

1: split type exhaust manifold, 2, 3: manifold, 4: end face inner diameter, 5: end face outer diameter,
6: fitting part, 7, 8: outer surface, 9: flexible pipe, 10, 11: communicating passage, 12: connecting part,
13: concave portion, 14: convex portion, 1
5: Fastening member 16: Outer diameter, 1
7: outer diameter.

Claims (4)

[Claims] 1. A split-type exhaust manifold having a structure in which a manifold is divided into a plurality of parts, and a fitting part into which an outer diameter of one manifold end is slidably inserted into an inner diameter of one manifold end, and a fitting part. And a flexible pipe for connecting and fixing the outer surface of each manifold so as to cover the portion. 2. The split type exhaust manifold according to claim 1, wherein the outer surface of each manifold fitting portion and the flexible pipe are connected and fixed by welding. 3. The connecting and fixing of the outer surface of each manifold fitting portion and the flexible pipe is carried out by engaging a convex portion or a concave portion formed on the outer surface of each manifold fitting portion with a concave portion or a convex portion provided at both ends of the flexible pipe. 2. The split type exhaust manifold according to claim 1, wherein the split type exhaust manifold is formed by a fastening member that straddles the outside of the concave portion or the convex portion of the flexible pipe. 4. The split type exhaust manifold according to claim 1, wherein the end face spacing of the manifold fitting portion is set to be slightly larger than a maximum value of a difference between thermal expansion and thermal contraction of the exhaust manifold.