JP4515816B2 - Exhaust manifold - Google Patents

Description

  The present invention relates to an exhaust manifold that collects exhaust gases exhausted from exhaust ports of a multi-cylinder internal combustion engine and sends them to an exhaust pipe.

Conventionally, increasing the heat resistance of the exhaust manifold by improving the reliability by the material, thickness, etc., increases the weight and heat capacity. Therefore, the exhaust gas is cooled when the internal combustion engine is started, and the purification action by the exhaust gas purification catalyst cannot be sufficiently obtained. Exhaust regulations have been further strengthened against global environmental problems in recent years. Therefore, as disclosed in Patent Document 1, a branch pipe connected to each exhaust port of an internal combustion engine and a set of branch pipes are gathered. The pipe is further covered with an outer shell member to form a double structure to keep the exhaust gas warm with an air layer.
JP-A-10-89063

However, these conventional devices have a double structure from the branch pipe to the collecting pipe, and there is a problem that the structure becomes complicated.
An object of the present invention is to provide an exhaust manifold capable of obtaining reliability with a simple structure.

In order to achieve this problem, the present invention has taken the following measures in order to solve the problem. That is,
In an exhaust manifold that connects an exhaust pipe to a collecting pipe part that aggregates branch pipe parts connected to each exhaust port of a multi-cylinder internal combustion engine, and sends exhaust gas exhausted from each exhaust port to the exhaust pipe,
An outer shell member in which the branch pipe part and the collecting pipe part are formed is provided, and an inner shell member is provided in the collecting pipe part to form a double structure , and the inner peripheral surface of the outer shell member and the A space is formed between the inner shell member and an outer peripheral surface of the inner shell member. The inner shell member is provided with a connecting pipe portion that is inserted into the branch pipe portion that is radially expanded on the collecting pipe portion side. An exhaust manifold is characterized in that a rib contacting the inner periphery of the expanded branch pipe portion is formed on the outer periphery of the portion so as to protrude over the entire periphery .

The inner shell member may include an upper portion and a lower portion, and the upper portion and the lower portion may be abutted to form a hollow shape, and the abutting portion may be fixed by caulking.

  Since the exhaust manifold of the present invention has a double structure by providing the inner shell member in the collecting pipe portion, there is an effect that reliability can be obtained with a simple structure.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.
As shown in FIG. 1, reference numeral 1 denotes an exhaust manifold, which is used in a four-cylinder internal combustion engine 100 in this embodiment. As shown in FIG. 4, the internal combustion engine 100 includes first to fourth exhaust ports P1 to P4 communicating with the first to fourth cylinders # 1 to # 4. In the present embodiment, ignition is performed in the order of the first cylinder # 1, the third cylinder # 3, the fourth cylinder # 4, and the second cylinder # 2.

  The exhaust manifold 1 includes a large flange 2, an outer shell member 4, and a small flange 6. The large flange 2 has four through holes 8 to 11 corresponding to the first to fourth exhaust ports P1 to P4. Has been. A plurality of attachment holes 12 to 19 for attaching the large flange 2 to the internal combustion engine 100 with bolts (not shown) are formed (see FIG. 1). A downstream exhaust pipe 102 is connected to the small flange 6 (see FIG. 3).

  The outer shell member 4 includes first to fourth branch pipe portions 20 to 23 and a collecting pipe portion 24, and the first branch pipe portion 20 is inserted and fixed in the through hole 8 communicating with the first exhaust port P1. ing. The second branch pipe portion 21 is inserted / fixed into the through hole 9 communicating with the second exhaust port P2, and the third branch pipe portion 22 is inserted / fixed into the through hole 10 communicated with the third exhaust port P3. The fourth branch pipe portion 23 is inserted and fixed in the through hole 11 communicating with the fourth exhaust port P4. The first branch pipe part 20 is connected to a joining branch pipe part 25 joined with the second branch pipe part 21, and the joining branch pipe part 25 is gathered in the collecting pipe part 24, and the third branch pipe part 22, Four branch pipe parts 23 are gathered in the collecting pipe part 24.

  The outer shell member 4 includes an upper portion 4a and a lower portion 4b. The upper portion 4a and the lower portion 4b are abutted to form a hollow interior, so-called a middle structure, and the first to fourth branch pipes. The parts 20 to 23 and the collecting pipe part 24 are formed. A connecting outer pipe 26 is connected to the collecting pipe portion 24 of the outer shell member 4, and a small flange 6 is attached to the connecting outer pipe 26.

  An inner shell member 28 is provided in the collecting pipe portion 24 of the outer shell member 4, and the inner shell member 28 includes an upper portion 28a and a lower portion 28b. The upper portion 28a and the lower portion 28b are abutted to form a hollow interior, that is, a so-called middle structure, and there is a space between the inner peripheral surface of the outer shell member 4 and the outer peripheral surface of the inner shell member 28. 30 is formed over the entire outer peripheral surface of the inner shell member 28.

  The inner shell member 28 is formed to have a size over the entire area of the collecting pipe portion 24 of the outer shell member 4, and the inner shell member 28 further includes a merging branch pipe portion 25, a third branch pipe portion 22, a fourth branch pipe portion. Connection pipe parts 32 to 34 to be inserted into the branch pipe part 23 are formed. Ribs 36 to 38 are formed on the outer circumferences of the connecting pipe portions 32 to 34 so as to protrude radially outward in a semicircular arc shape.

  Each of the ribs 36 to 38 is formed so as to come into contact with the inner periphery of the merging branch pipe part 25, the third branch pipe part 22, and the fourth branch pipe part 23 with an interference. In this embodiment, the merging branch pipe part 25, the third branch pipe part 22, and the fourth branch pipe part 23 are formed by radially inflating the collecting pipe part 24 side, and this swelled merging branch pipe part 25, when the outer diameter of each of the ribs 36 to 38 is slightly larger than the inner diameter of the third branch pipe part 22 and the fourth branch pipe part 23, and when the inner shell member 28 is stored in the collecting pipe part 24, Each rib 36-38 is elastically deformed and formed so as to contact. By this contact, the communication between the space 30 and the merge branch pipe part 25, the third branch pipe part 22, and the fourth branch pipe part 23 is blocked.

  Moreover, each connection pipe part 32-34 is formed in the length which can insert each rib 36-38 in the merge branch pipe part 25, the 3rd branch pipe part 22, and the 4th branch pipe part 23, The connection pipe parts 32 to 34 are opened in the merge branch pipe part 25, the third branch pipe part 22, and the fourth branch pipe part 23, respectively. It is preferable that the inner diameters of the connection pipe portions 32 to 34 are formed to be substantially equal to the inner diameters of the merging branch pipe portion 25, the third branch pipe portion 22, and the fourth branch pipe portion 23.

  The upper portion 28a and the lower portion 28b of the inner shell member 28 are integrally fixed by caulking as shown in FIG. That is, the ear portion 40 is formed on the outer periphery of the upper portion 28a, the ear portion 42 formed on the outer periphery of the lower portion 28b is bent, and the ear portion 40 of the upper portion 28a is sandwiched.

  On the other hand, a connection inner tube 44 is coaxially arranged in the connection outer tube 26, and the connection inner tube 44 is inserted into the inner shell member 28 and connected to the inside of the inner shell member 28. The connection inner tube 44 is supported by the connection outer tube 26 via a support member 46 such as a wire mesh mounted on the outer periphery.

Next, the operation of the exhaust manifold of the present embodiment described above will be described.
First, as the internal combustion engine 100 is operated, exhaust gas is discharged from the first to fourth exhaust ports P1 to P4. The discharged exhaust gas flows into the exhaust manifold 1 from the first to fourth branch pipe portions 20 to 23, and is led into the inner shell member 28 from the first to fourth branch pipe portions 20 to 23, and the inner shell. It flows out from the member 28 to the exhaust pipe 102 on the downstream side through the connection inner pipe 44.

  In the internal combustion engine 100, the first cylinder # 1, the third cylinder # 3, the fourth cylinder # 4, and the second cylinder # 2 are ignited in this order, so that the exhaust gas is in the first branch pipe section 20 and the third branch pipe section. 22, the 4th branch pipe part 23, and the 2nd branch pipe part 21 flow in order. The exhaust gas from the first cylinder # 1 that has flowed into the first branch pipe portion 20 flows into the inner shell member 28 from the merging branch pipe portion 25 and the connection pipe portion 32, and passes through the connection inner pipe 44 from the inner shell member 28. And flows out to the exhaust pipe 102 on the downstream side. The exhaust gas from the third cylinder # 3 that has flowed into the third branch pipe portion 22 flows into the inner shell member 28 from the connection pipe portion 33, passes through the connection inner pipe 44 from the inner shell member 28, and is exhausted downstream. It flows out to the tube 102.

  The exhaust gas from the fourth cylinder # 4 that has flowed into the fourth branch pipe portion 23 flows into the inner shell member 28 from the connection pipe portion 34, passes through the connection inner pipe 44 from the inner shell member 28, and is exhausted downstream. It flows out to the tube 102. The exhaust gas from the second cylinder # 2 that has flowed into the second branch pipe portion 21 flows into the inner shell member 28 from the merging branch pipe portion 25 and the connection pipe portion 32, and passes through the connection inner pipe 44 from the inner shell member 28. And flows out to the exhaust pipe 102 on the downstream side. This is repeated in order as the internal combustion engine 100 is operated.

  As described above, the exhaust gas from the first to fourth cylinders # 1 to # 4 individually passes through the first to fourth branch pipe portions 20 to 23 and passes through the connecting pipe portions 32 to 34, respectively. It flows into the member 28 and is assembled in the inner shell member 28. Since the exhaust gas individually passes through each of the first to fourth branch pipe portions 20 to 23, the exhaust gas passes intermittently through each of the first to fourth branch pipe portions 20 to 23, and the first to fourth branches. The temperature rise of the pipe parts 20-23 is small, and the surface temperature of each 1st-4th branch pipe part 20-23 does not become high temperature easily.

  On the other hand, in the inner shell member 28, the exhaust gas from each of the first to fourth branch pipe portions 20-23 is collected, so that the exhaust gas flows continuously. Since the collecting pipe portion 24 and the inner shell member 28 form a double structure and heat insulation is achieved by the space 30, it is possible to prevent the surface temperature of the collecting pipe portion 24 of the outer shell member 4 from becoming high.

  Therefore, the outer shell member 4 can be formed of a material having low heat resistance, and the thickness of the outer shell member 4 can be reduced, thereby reducing the cost. Further, since the inner shell member 28 is provided, it is possible to prevent the temperature of the collecting pipe portion 24 from being increased, and the reliability is improved. The inner shell member 28 is provided in the collecting pipe portion 24, and each of the first to fourth branches is provided. Since the pipe portions 20 to 23 are not provided, the structure is simplified and the manufacture is easy.

  In addition, the upper shell 4a and the lower shell 4b of the outer shell member 4 are brought into contact with each other, and the inner shell member 28 is accommodated therein, so that the first to fourth branch pipe portions 20-23 are formed by the ribs 36-38. Since the inflowing exhaust gas can be restricted from flowing into the space 30, manufacturing is easy. Since the ribs 36 to 38 can be formed by pressing, the ribs 36 to 38 can be easily manufactured. Furthermore, the inner shell member 28 is configured by abutting the upper portion 28a and the lower portion 28b and fixing them by caulking, so that the inner shell member 28 can be configured more simply than by abutting the entire circumference by welding or the like.

  The present invention is not limited to such embodiments as described above, and can be implemented in various modes without departing from the gist of the present invention.

It is a front view of the exhaust manifold as one embodiment of the present invention. It is a top view of the exhaust manifold of this embodiment. It is a side view of the exhaust manifold of this embodiment. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Exhaust manifold 2 ... Large flange 4 ... Outer shell member 6 ... Small flange 20 ... 1st branch pipe part 21 ... 2nd branch pipe part 22 ... 3rd branch pipe part 23 ... 4th branch pipe part 24 ... Collecting pipe part 25 ... Junction branch pipe part 26 ... Connection outer pipe 28 ... Inner shell member 30 ... Space 32-34 ... Connection pipe part 36-38 ... Rib 44 ... Connection inner pipe 100 ... Internal combustion engine 102 ... Exhaust pipe

Claims (2)

In an exhaust manifold that connects an exhaust pipe to a collecting pipe part that aggregates branch pipe parts connected to each exhaust port of a multi-cylinder internal combustion engine, and sends exhaust gas exhausted from each exhaust port to the exhaust pipe,
An outer shell member in which the branch pipe part and the collecting pipe part are formed is provided, and an inner shell member is provided in the collecting pipe part to form a double structure , and the inner peripheral surface of the outer shell member and the A space is formed between the inner shell member and an outer peripheral surface of the inner shell member. The inner shell member is provided with a connecting pipe portion that is inserted into the branch pipe portion that is radially expanded on the collecting pipe portion side. An exhaust manifold characterized in that a rib contacting the inner periphery of the swollen branch pipe portion is formed on the outer periphery of the portion so as to protrude over the entire periphery . The inner shell member is provided with an upper portion and a lower portion, thereby forming a hollow butt and said lower portion and said upper portion, to claim 1, characterized in that fixed by caulking the butting portion Exhaust manifold as described.

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