JPH0674038A - Exhaust manifold - Google Patents

Abstract

PURPOSE:To prevent crack generation on a partition wall and around it by composing the partition wall of members which are different from those of a mainfold main body to structure a peripheral wall of an outlet passage, fixing it to the mainfold main body, forming a gap between the partition wall and an inner surface on a downstream of the outlet passage, and thereby eliminating restriction caused by thermall expansion of the partition wall. CONSTITUTION:A partition wall is composed of a partition wall main body 3a and a flange part 3b. The partition wall main body 3a is arranged inside an outlet passage 5 such that the exhaust gas flowing from one group of inlet passages 4a, 4b, 4c to the outlet passage 5 does not interfere with the exhaust gas flowing from the other group of inlet passages 4d, 4e, 4f to the outlet passage 5. The flange part 3b is fixed to an outlet side end face of a peripheral wall which composes the outlet passage 5 by means of a bolt. A gap 8 is formed between the partition wall main body 3a and an inner surface 5a on an upstream of the outlet passage 5, while the partition wall 3 is made up of members which are different from those of a mainfold main body 2. Thermal stress caused by temperature rising is eliminated and crack generation on the partition wall and around it is prevented, accordingly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust manifold for a multi-cylinder internal combustion engine equipped with an exhaust turbocharger.

[0002]

2. Description of the Related Art The conventional exhaust manifold shown in FIG.
Each of the inlet passages 102 is provided with a plurality of inlet passages 102a and 102b communicating with the exhaust port of the multi-cylinder internal combustion engine, and a single outlet passage 103 communicating with the inlet of the exhaust turbocharger.
a and 102b are divided into two groups according to the flow direction of the exhaust gas. The exhaust gas from one group's inlet passage 102a toward the outlet passage 103 via the intermediate passage 105a and the other group's inlet passage 102b A partition wall 104 that divides the outlet passage 103 into two is provided so as not to interfere with the exhaust gas flowing toward the outlet passage 103 through the passage 105b. The partition wall 104 prevents the exhaust gas from interfering with each other, thereby preventing a decrease in turbine efficiency. In addition, each passage 102a, 102b, 103,
The manifold body 101 forming the peripheral walls of 105a and 105b is provided with a cooling water jacket 106 for preventing a fire or the like.
Is cooled by.

[0003]

However, the outlet passage 10
Since the partition wall 104 located inside 3 is exposed to the exhaust gas, it becomes hotter than the peripheral wall of the outlet passage 103. Therefore, during engine operation, a high compressive stress is generated such that the thermal expansion of the partition wall 104 is restrained and plastic deformation occurs. Further, when the partition wall temperature decreases due to the stop of engine operation, plastic deformation occurs, so tensile stress is generated. Occurs. Due to the repeated action of such stress, a crack 107 may occur in the partition wall 104 and its peripheral portion due to fatigue. In particular, when the manifold body 101 is cooled by the cooling water jacket 106, the temperature of the cooling water becomes high when the engine operation is stopped, so that the temperature of the partition wall 104 decreases faster than the temperature of the peripheral wall of the outlet passage 103, and a large tensile stress occurs. Acts to promote the generation of cracks.

Therefore, it has been proposed to provide a recess at the end of the partition wall on the outlet side and cast a reinforcing member into the recess (see Japanese Utility Model Laid-Open No. 63-96216). Due to the difference in expansion coefficient, there is a risk of peeling between the reinforcing member and the inner surface of the recess, or cracking around the reinforcing member.

Further, it has been proposed to form a half-moon shaped slit in the partition wall, form a groove along the inner surface of the slit, and insert a half-moon shaped heat-resistant piece into the groove. No. 63-121), cracks may occur due to stress concentration in the groove forming portion.

Further, it has been conventionally practiced to provide a single slit at the outlet side end of the partition wall, but it has been confirmed that providing such a single slit has no effect in preventing cracks. ing.

An object of the present invention is to provide an exhaust manifold which can solve the above-mentioned problems of the prior art.

[0008]

The first aspect of the present invention is characterized in that a plurality of inlet passages communicating with an exhaust port of a multi-cylinder internal combustion engine and a single outlet communicating with an inlet of an exhaust turbocharger. Each of the inlet passages is divided into two groups according to the flow direction of the exhaust gas, and the exhaust gas from the inlet passage of one group to the outlet passage and the exhaust gas from the inlet passage of the other group to the outlet passage. In an exhaust manifold provided with a partition wall that divides the outlet passage into two so as not to interfere with gas, the partition wall is formed of a member different from the manifold main body forming the peripheral wall of the outlet passage, and the manifold main body. It is fixed to the partition wall, and a gap is formed between the partition wall and the inner surface on the upstream side of the outlet passage.

The second aspect of the present invention is characterized in that a plurality of inlet passages communicating with an exhaust port of a multi-cylinder internal combustion engine are provided.
A single outlet passage communicating with the inlet of the exhaust turbocharger, each inlet passage is divided into two groups according to the flow direction of the exhaust gas, and the exhaust passage from one inlet passage to the outlet passage One side of the outlet passage separated by the partition wall in an exhaust manifold provided with a partition wall separating the outlet path so that the gas and the exhaust gas flowing from the inlet path of the other group toward the outlet path do not interfere with each other. At least two slits communicating with the other side are formed at intervals from each other so as to extend from the outlet side end of the partition wall toward the upstream side.

[0010]

According to the structure of the first aspect of the present invention, the partition wall is formed of a member different from the manifold main body forming the peripheral wall of the outlet passage, and a gap is formed between the partition wall and the inner surface on the upstream side of the outlet passage. Therefore, the thermal expansion due to the temperature rise is hardly or not restrained at all, and the thermal stress generated therein can be reduced or eliminated.

According to the structure of the second aspect of the present invention, the restraint of thermal expansion due to temperature rise is reduced between at least two slits formed so as to extend from the outlet side end of the partition wall toward the upstream side, and the inside thereof is reduced. The thermal stress generated in the is reduced.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

The exhaust manifold 1 of the first embodiment shown in FIGS. 1 and 2 is composed of a cast iron manifold body 2 and a partition wall 3 made of a heat resistant material such as SUS material, which is different from the manifold body 2. ing. The manifold body 2
Comprises a plurality of inlet passages 4a, 4b, 4c, 4d, 4e, 4f communicating with the exhaust port of the multi-cylinder internal combustion engine, and a single outlet passage 5 communicating with the inlet of the exhaust turbocharger,
Each inlet passage 4a, 4b, 4c, 4d, 4e, 4f is shown in FIG.
In the figure, as indicated by the arrow, they are divided into two groups according to the flow direction of the exhaust gas. The manifold body 2 also includes a first intermediate passage 6 for guiding exhaust gas from one of the inlet passages 4a, 4b, 4c toward the outlet passage 5.
And a second intermediate passage 7 that guides the exhaust gas flowing from the inlet passages 4d, 4e, 4f of the other group toward the outlet passage 5. In addition, each passage 4a is provided in the manifold main body 2,
A water cooling jacket 9 that integrally covers 4b, 4c, 4d, 4e, 4f, 5, 6, and 7 is provided.

The partition wall 3 comprises a partition wall body 3a and a flange portion 3
b, the partition body 3a has exhaust gas directed from one group of inlet passages 4a, 4b, 4c to the outlet passage 5 and exhaust gas directed from the other group's inlet passages 4d, 4e, 4f to the outlet passage 5. Are arranged in the outlet passage 5 so that they do not interfere with each other, and the flange portion 3b is fixed to the end face on the outlet side of the peripheral wall forming the outlet passage 5 by a bolt. For this fixing, bolt holes 3b ', 5'are formed in the flange portion 3b and the peripheral wall forming the outlet passage 5. In the fixed state of the partition wall 3, a gap δ is formed between the partition wall body 3a and the upstream inner surface 5a of the outlet passage 5. Note that the specific size of the gap δ is appropriately set within a range in which the effect of preventing the interference of exhaust gas by the partition wall 3 is not impaired and the constraint of thermal expansion of the partition wall 3 by the peripheral wall of the outlet passage 5 is not excessive. .

According to the above construction, the partition wall 3 is formed of a member different from the manifold main body 2, and the gap δ is formed between the partition wall 3 and the inner surface 5a on the upstream side of the outlet passage 5. The expansion is hardly or completely unrestrained, and the thermal stress generated inside can be reduced or eliminated. As a result, it is possible to prevent the occurrence of cracks in the partition wall 3 and its peripheral portion.

The exhaust manifold 11 of the second embodiment shown in FIGS. 3 to 5 is made of cast iron, and has a plurality of inlet passages 14a and 14d communicating with the exhaust port of a multi-cylinder internal combustion engine, and an exhaust turbocharger. A single outlet passage 15 communicating with the inlet is provided, and each inlet passage 14a, 14d is divided into two groups according to the flow direction of the exhaust gas as shown by the arrow in FIG. The exhaust manifold 11 also includes a first intermediate passage 16 for guiding exhaust gas from the inlet passage 14a of one group to the outlet passage 15, and a first intermediate passage 16 for guiding exhaust gas from the inlet passage 14d of the other group to the outlet passage 15. 2 intermediate passages 17 and. In addition, the exhaust manifold 11 has passages 14a, 14d, 15, 16,
A water cooling jacket 19 covering 17 is integrally provided.

The two outlet passages 15 are provided so that the exhaust gas flowing from the inlet passage 14a of one group to the outlet passage 15 and the exhaust gas traveling from the inlet passage 14d of the other group to the outlet passage 15 do not interfere with each other. Partition wall 1
3 is provided integrally with the exhaust manifold. Two slits 20 and 21 that connect one side and the other side of the outlet passage 15 that are separated by the partition wall 13 are formed so as to face the upstream side from the outlet side end of the partition wall 15 at intervals. The widths t and the depths D of the slits 20 and 21 are within a range in which the effect of preventing the interference of the exhaust gas by the partition wall 13 is not impaired and the restriction of the thermal expansion of the partition wall 13 by the peripheral wall of the outlet passage 15 is not excessive. Set appropriately. In this embodiment, the width t is about 1 to 1.5 mm,
The depth D is about 1/3 of the depth of the partition wall 13. Further, as shown in FIG. 5, the bottoms of the slits 20 and 21 have hole-shaped portions 20a and 21b having a diameter of about three times the slit width t.
Therefore, stress concentration is prevented.

According to the above structure, the restriction of thermal expansion due to the temperature rise is reduced between the two slits 20 and 21 formed so as to extend from the outlet side end of the partition wall 13 toward the upstream side, and the inside thereof is reduced. Since the thermal stress generated in the partition wall 3 is reduced, it is possible to prevent the occurrence of cracks in the partition wall 3 and its peripheral portion.

The present invention is not limited to the above embodiment. For example, although the manifold body and the partition wall are made of different materials in the first embodiment, they may be made of the same material.
Further, the fixing means for the manifold body and the partition is not limited to the bolt. Further, in the second embodiment described above, the slits formed in the partition wall are two, but may be three or more. Further, although the present invention is applied to the exhaust manifold having the water cooling jacket in each of the above-described embodiments, the present invention can also be applied to the air-cooled exhaust manifold.

[0020]

According to the exhaust manifold of the present invention, it is possible to prevent cracks from occurring in the partition wall and its peripheral portion by reducing or eliminating the restriction of thermal expansion of the partition wall that separates the outlet passage.

[Brief description of drawings]

FIG. 1 is a perspective view of an exhaust manifold according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an exhaust manifold according to the first embodiment of the present invention.

FIG. 3 is a perspective view of an exhaust manifold according to a second embodiment of the present invention.

FIG. 4 is a sectional view of an exhaust manifold according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a main part of an exhaust manifold according to a second embodiment of the present invention.

FIG. 6 is a perspective view of a conventional exhaust manifold.

[Explanation of symbols]

 3, 13 Partition walls 4a to 4f, 14a to 14f Inlet passage 5, 15 Outlet passage 20, 21 Slit

Claims (2)

[Claims] 1. A plurality of inlet passages communicating with an exhaust port of a multi-cylinder internal combustion engine and a single outlet passage communicating with an inlet of an exhaust turbocharger, each inlet passage extending in a flow direction of exhaust gas. The exhaust passages are divided into two groups according to the number, and the outlet passages are divided into two so that the exhaust gas flowing from the inlet passage of one group to the outlet passage does not interfere with the exhaust gas traveling from the inlet passage of the other group to the outlet passage. In an exhaust manifold provided with a partition wall that separates it, the partition wall is formed of a member different from the manifold main body that forms the peripheral wall of the outlet passage, and is fixed to the manifold main body. An exhaust manifold characterized in that a gap is formed between the exhaust manifold. 2. A multi-cylinder internal combustion engine comprising a plurality of inlet passages communicating with an exhaust port and a single outlet passage communicating with an inlet of an exhaust turbocharger, each inlet passage extending in a flow direction of exhaust gas. The exhaust passages are divided into two groups according to the number, and the outlet passages are divided into two so that the exhaust gas flowing from the inlet passage of one group to the outlet passage does not interfere with the exhaust gas traveling from the inlet passage of the other group to the outlet passage. In an exhaust manifold provided with a partition wall that separates, at least two slits that communicate one side and the other side of the outlet passage that are separated by the partition wall are spaced apart from each other and extend from the outlet side end of the partition wall toward the upstream side. An exhaust manifold characterized by being formed as follows.