JPH0515533Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to the structure of an exhaust manifold for a turbocharger, such as a so-called twin entry type turbocharger, in which the scroll of a turbine housing is divided into two parts.

[Prior art] In a twin-entry turbocharger, the scroll of the turbine housing is divided into two parts.
Each divided scroll is connected to each cylinder group divided into two groups so that exhaust interference does not occur. This structure is effective for effectively utilizing the dynamic pressure of exhaust gas and performing efficient supercharging.

In order to connect the twin entry type turbocharger and the exhaust manifold, it is common to use a structure in which the flange surface of the turbocharger's turbine housing and the mounting surface of the exhaust manifold are aligned and fastened with bolts and nuts.

The flange mounting surface of the turbocharger and the exhaust manifold has the problem of distortion due to thermal expansion caused by the high temperature of the exhaust gas. In particular, when the turbocharger is of the twin entry type, this thermal expansion tends to cause deterioration of the seal at the joint flange portion between the exhaust manifold and the turbine housing. This is due to the following reason. That is, the mounting surface of the exhaust manifold is provided with a partition wall that separates two groups of cylinders, but due to the high temperature of the exhaust gas, it thermally expands and lifts, resulting in the two cylinder groups separated by this partition wall. There is a problem in that exhaust gas leaks between the exhaust gas passages of the engine, deteriorating supercharging performance.

[Problem that the invention attempts to solve]

Japanese Utility Model Application No. 61-74623 proposes a system in which a cross-shaped reinforcing member made of a heat-resistant material is disposed at the joint flange between the turbocharger and the exhaust manifold. This arrangement is intended to suppress thermal expansion and prevent damage.

However, such a cross-shaped arrangement of heat-resistant materials has some effect on thermal expansion. However, a compressive force acts on the flange connection between the exhaust manifold and the turbocharger in the direction in which the branch pipes are lined up, and the connection tends to be restrained in this direction and to expand in a direction perpendicular to this direction. The cross-shaped structure is not effective against such elongation and has the problem of increasing deformation.

The purpose of this invention is to provide a structure that suppresses thermal deformation in a direction perpendicular to the direction in which branch pipes to each cylinder of an exhaust manifold are lined up.

[Means for solving problems]

According to this invention, the cylinders of an internal combustion engine are divided into two groups, and the exhaust manifold has two pipe sections separated by a central partition that receive exhaust gas from branch pipes connected to the cylinders of each group. However, in a turbocharger having two exhaust gas inlets for connecting to each pipe separately, a recess is formed in the end face of the exhaust manifold where the two pipes open, and a heat-resistant member is inserted into the recess. is fitted, the heat-resistant member consists of a peripheral portion surrounding the open end of the tube section, and a central wall portion connecting the peripheral portions together and located on the central bulkhead of the exhaust manifold, the heat-resistant member comprising: There is provided an exhaust manifold for an internal combustion engine with a turbocharger, characterized in that the wall thickness of the side parallel to the direction in which the branch pipes are arranged is larger than the wall thickness of the side in the direction orthogonal to this direction.

〔Example〕

In FIG. 4, 10 indicates an exhaust manifold of a six-cylinder internal combustion engine. The exhaust manifold 10 includes a branch pipe 12 connected to an exhaust port (not shown) of each cylinder, and a branch pipe 12 that collects the branch pipes 12 of the first cylinder (#1) to the third cylinder (#3). 1 pipe portion 14a and the fourth cylinder #4 to the sixth cylinder #6
and a second pipe section 14b that collects the branch pipes 12 of the cylinders. Here, the cylinders from #1 to #3,
The reason for grouping the cylinders into cylinders #4 to #6 is to cause ignition to occur alternately between these two cylinders. Here the firing order is #1, #5, #3, #6,
Assume that #2 and #4 are used. The turbocharger 15 is of a so-called twin entry type, and the turbine housing 16 has two parallel scrolls 1.
It has 8a and 18b. Turbine housing 16
The exhaust manifold 10 includes a flange portion 20 connected to the mounting surface 17 of the exhaust manifold 10.
It has two exhaust gas inlet parts 22a, 22b connected to two pipe parts 14a, 14b. In addition, 2
4 is a turbine wheel, and 26 is a compressor wheel.

In FIG. 1, 27 is a bolt hole through which a bolt (not shown) that connects the turbine housing 16 and the exhaust manifold 10 to each other is inserted. The exhaust manifold 10 has a mounting surface 17 with the flange portion 20 of the turbine housing.
At , the reinforcing member 30 is cast. The reinforcing member 30 is made of ceramic or the like (for example, SiC, Si ₃ N ₄ ,
Made of heat-resistant materials such as ZrO ₂ , ZrSiO ₄ ).
The reinforcing member 30 includes a rectangular annular surrounding portion 30-1;
It is composed of a central wall portion 30-2. The surrounding portion 30-1 is arranged in the direction x in which the branch pipes of the exhaust manifold are arranged.
The side parallel to y has a thick wall thickness t ₁ , and the side parallel to the direction y perpendicular to the same direction has a thin wall thickness t ₂ . The central wall portion 30-2 is located above the bulkhead 28 separating the pipe portions 14a, 14b of each cylinder group, and the peripheral portion is located above the recess 32 formed in the end face of the exhaust manifold. Surrounding part 30-2
Forms a tapered upper outer surface 30' which is widened on the inside to prevent it from coming off. Furthermore, the four corners 34 of the surrounding portion 30-1 are formed to be rounded in order to alleviate stress concentration. Central wall portion 30-2 and surrounding portion 30
There is an R section 36 at the connection point with -1, and this radius
R ₁ is considerably larger than the radius R ₂ of the four corners 34 of the peripheral portion. Central wall portion 30- of reinforcing member 30
2 and the bulkhead 28 of the exhaust manifold, the bulkhead 28 has a shelf 38 . This is inevitably possible because the reinforcing member 30 is held by the core during casting. That is, to explain the process of casting the reinforcing member, in FIG. requires the protrusion 40a. When pouring hot water into the mold space 44, this protrusion 40
a prevents hot water from entering the circumferential surface of the heat-resistant member 30; When such hot water enters, burrs are generated, and these burrs apply an uneven load during solidification, so
Although there is a risk of causing cracks, in this invention, the protrusions 40a have the effect of blocking such a flow of molten metal, and no burrs are generated during casting.

When the engine is operating, the exhaust gas becomes hot, so the exhaust manifold 10 is heated. Since the reinforcing member 30 is made of heat-resistant ceramic or the like, it is possible to suppress thermal deformation of the mounting surface 17 to the turbocharger. That is, in the prior art, since the entire mounting surface 17 was made of casting, the mounting surface 17 significantly thermally expanded due to the high temperature of the exhaust gas, and the four corners of the flange of the partition wall 28 in particular passed through the bolt holes 27. Since it is held down by a bolt (not shown), it deforms into an upwardly convex shape. Therefore, there was a risk that exhaust gas would leak between the exhaust gas passages divided by the partition wall 28. On the other hand, in this invention, since the reinforcing member 30 is made of heat-resistant ceramic material or the like on the mounting surface 17, the partition wall 2
Thermal expansion of the center wall portion 30-1 located above the center wall portion 8 is not large and can be ignored, and gas sealing performance is maintained well. Also, exhaust manifold 1
In the process of thermal expansion of
Since the exhaust manifold 10 is pressed down from above by the turbine housing 20 (FIG. 4), an elongated and tensile force acts in the direction of arrow B. The compressive force (arrow A) is affected by the thicker portion of the surrounding portion 30-1, such as _t1 . Also, the R ₁ part is effective against tension. Therefore, it becomes strong against compression and tension, and can protect the reinforcing member 30.

[Effect of idea]

According to this invention, in an internal combustion engine equipped with a twin-entry turbocharger, a heat insulating member made of ceramic or the like consisting of a peripheral portion and a central wall portion is cast on the mounting surface of the exhaust manifold to the turbine housing. It is possible to maintain good sealing performance, and it is also possible to prevent deformation in a direction perpendicular to the direction in which the cylinders are lined up due to compression force.

[Brief explanation of the drawing]

FIG. 1 is a top view of the flange portion of the exhaust manifold of the first embodiment of this invention. FIG. 2 is a sectional view taken along the - line in FIG. 1. FIG. 3 is a diagram illustrating the shape of a core for making the exhaust manifold of the first embodiment. FIG. 4 is a schematic configuration diagram of a twin entry type turbocharger device. 10... Exhaust manifold, 12... Branch pipe, 1
4a, 14a...Pipe portion, 15...Turbocharger, 16...Turbine housing, 17...Mounting surface, 20...Flange, 28...Partition wall, 30...
... Reinforcement member, 38 ... Shelf section, 40 ... Core, 40
a... Protrusion.

Claims (1)

[Scope of utility model registration request] The cylinders of the internal combustion engine are divided into two groups, and the exhaust manifold has two pipe sections separated by a central partition that receive exhaust gas from branch pipes connected to the cylinders of each group. A recess 32 is formed in the end face of the exhaust manifold where the two pipe parts 14a and 14b open, and a heat-resistant member 30 is inserted into the recess.
is fitted, and the heat-resistant member 30 is connected to the tube portions 14a, 14
a peripheral portion 30-1 surrounding the open end of b; and a central wall portion 30 that integrally connects the peripheral portion 30-1 and is located on the central partition wall 28 of the exhaust manifold 10.
-2, and the wall thickness t ₁ of the side parallel to the direction in which the branch pipes are lined up in the peripheral portion 30-1 is larger than the wall thickness t ₂ of the side in the direction orthogonal to this direction. Exhaust manifold for internal combustion engines.