JP2010084708A - Exhaust system for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology that suppresses exhaust gas from being cooled in an exhaust collecting space where the exhaust gas discharged from exhaust ports is collected in an exhaust system for an internal combustion engine. <P>SOLUTION: This exhaust system includes a recessed part 9 having the opening 51 of a plurality of exhaust ports 5 formed on the inner face thereof in a cylinder head 3, and a cover part 11 forming an exhaust gas collecting space 12 for collecting exhaust gas between itself and the recess 9 in an exhaust manifold 10 connected to the cylinder head 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an exhaust device for an internal combustion engine.

In the exhaust manifold, the collecting pipe part that forms the exhaust collecting space part that collects the exhaust discharged from the exhaust port of the cylinder head has a double structure in which the inner pipe is covered with the outer pipe, and the exhaust is cooled in the exhaust collecting space part. The technique which suppresses that is performed is disclosed (for example, refer patent document 1).
Japanese Patent Laid-Open No. 10-252457 JP 2000-161129 A JP-A-8-21233

  However, in the technique such as Patent Document 1, since the surface area of the portion exposed to the outside air in the collecting pipe portion of the exhaust manifold is large and the collecting pipe portion easily radiates heat, the exhaust gas can be sufficiently kept warm in the exhaust collecting space portion. I couldn't.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an exhaust system for an internal combustion engine in which exhaust is cooled in an exhaust collecting space for collecting exhaust discharged from an exhaust port. It is to provide a technology to suppress.

In the present invention, the following configuration is adopted. That is, the present invention
In the cylinder head, a concave portion in which openings of a plurality of exhaust ports are formed on the inner surface;
A cover part that forms an exhaust collecting space part that collects exhaust gas between the concave part in the exhaust collecting pipe connected to the cylinder head;
An exhaust device for an internal combustion engine, comprising:

  According to the present invention, it is possible to form the exhaust collecting space portion for collecting the exhaust discharged from the exhaust port of the cylinder head by the recess and the cover portion. For this reason, a part of the exhaust collecting space portion is formed by a concave portion of the cylinder head, and the concave portion is not exposed to the outside. Therefore, the part exposed to the outside air of the member forming the exhaust collecting space is only the cover part, and the surface area of the part exposed to the outside air can be reduced. Therefore, since the member forming the exhaust collective space portion is difficult to dissipate heat, it is possible to prevent the exhaust from being cooled in the exhaust collective space portion.

  According to the present invention, since the concave portion is formed in the cylinder head, the exhaust port formed in the cylinder head is shortened. Therefore, the heat transfer area to the cylinder head in which the exhaust port is formed can be reduced. Therefore, since heat loss when exhaust passes through the exhaust port is reduced, it is possible to suppress the exhaust reaching the exhaust collecting space from being cooled. Further, since the exhaust port is short, the volume of the exhaust circulation path can be reduced. Therefore, the exhaust energy can be efficiently supplied to the turbine of the downstream turbocharger.

  According to the present invention, since the exhaust collecting space can be formed only by the recess and the cover, the shape of the exhaust collecting space can be simplified. Therefore, since the number of welding points can be reduced or the number of component parts can be reduced, the cost can be reduced.

  According to the present invention, since the exhaust collecting space portion can be formed only by the recess and the cover portion, the shape of the exhaust collecting space portion can be made compact. Therefore, it becomes easy to mount the exhaust assembly space portion, and it is possible to make a space between the peripheral parts and to prevent thermal damage to the peripheral parts.

  An annular opening end portion of the cover portion is smaller than an opening portion of the recessed portion, and when the exhaust collecting pipe is connected to the cylinder head, the annular opening end portion of the cover portion is inserted into the recessed portion, A heat insulating layer may be formed between the cover portion and the recess at a portion where the cover portion and the recess overlap.

  According to the present invention, since the heat insulating layer is formed between the cover portion and the concave portion, the concave portion exposed to the exhaust collecting space portion is reduced, and the heat transfer area to the cylinder head where the concave portion is formed can be reduced. Therefore, since heat loss when the exhaust exists in the exhaust collecting space portion is reduced, it is possible to suppress the exhaust of the exhaust collecting space portion from being cooled.

  The surface of the concave portion and the cover portion forming the exhaust collecting space portion may be coated with a corrosion-resistant coating material.

  Condensed water accumulates in the exhaust collecting space and corrosion may occur. On the other hand, according to the present invention, the surface of the concave portion and the cover portion forming the exhaust collecting space portion is coated with a corrosion-resistant coating material, so that even if condensed water accumulates in the exhaust collecting space portion, corrosion is prevented. it can.

  The corrosion-resistant coating material may have a heat insulating property.

  According to the present invention, since the corrosion-resistant coating material has a heat insulating property, it is possible to reduce the amount of heat transfer to the cylinder head and the cover portion in which the recesses are formed. Therefore, since heat loss when the exhaust exists in the exhaust collecting space portion is reduced, it is possible to suppress the exhaust of the exhaust collecting space portion from being cooled.

  When the exhaust collecting pipe is connected to the cylinder head, a gasket interposed between the concave portion and the cover portion may be provided.

  According to the present invention, the gasket is interposed between the concave portion and the cover portion, so that the sealing property between the concave portion and the cover portion can be improved without requiring welding or the like. Moreover, since the number of welding points can be reduced, cost reduction can be achieved.

  The gasket may be integrated with a heat shield.

  According to the present invention, since the gasket is integrated with the heat shield and has heat insulation, the amount of heat transfer to the gasket can be reduced. Therefore, since heat loss when the exhaust exists in the exhaust collecting space portion is reduced, it is possible to suppress the exhaust of the exhaust collecting space portion from being cooled.

  It is good to provide the annular protrusion part which protrudes from the opening part peripheral part of the said exhaust port of the inner surface of the said recessed part, and extends the length of the said exhaust port.

  According to the present invention, the length of the exhaust port can be extended by the annular protrusion. Therefore, the intake and exhaust efficiency can be improved by using exhaust pulsation due to strong blowdown from the exhaust port extended by the annular protrusion.

  According to the present invention, in the exhaust device of the internal combustion engine, it is possible to suppress the exhaust from being cooled in the exhaust collecting space that collects the exhaust discharged from the exhaust port.

  Specific examples of the present invention will be described below.

<Example 1>
FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine to which an exhaust system for an internal combustion engine according to this embodiment is applied and an exhaust system thereof. An internal combustion engine 1 shown in FIG. 1 is a water-cooled four-stroke cycle diesel engine having four cylinders 2. The cylinder head 3 of the internal combustion engine 1 is provided with two intake ports 4 and two exhaust ports 5 each communicating with a combustion chamber in the cylinder 2. The cylinder head 3 is provided with an intake valve 6 that opens and closes the intake port 4 and an exhaust valve 7 that opens and closes the exhaust port 5. The cylinder head 3 is provided with a fuel injection valve 8 that injects fuel into the combustion chamber.

  As shown in FIG. 1, a concave portion 9 having a semicircular cross section is formed on the side surface 31 of the cylinder head 3. An opening 51 of the exhaust port 5 is formed on the inner surface of the recess 9. That is, as shown in FIG. 2, the openings 51 of all eight exhaust ports 5 exist in parallel in the inner surface region of the recess 9. The exhaust port 5 has a length from the side surface 31 of the cylinder head 3 to the inner surface of the recessed portion 9 that is recessed, and is short.

  An exhaust manifold 10 is connected to the cylinder head 3. At the time of this connection, the concave portion 9 of the cylinder head 3 is covered with the cover portion 11 of the exhaust manifold 10. The cover part 11 is semicircular in cross section as shown in FIG. 1 and has a hollow interior. As a result, when the recess 9 is covered with the cover portion 11, the space surrounded by the recess 9 and the cover portion 11 becomes an exhaust collecting space portion 12 that collects the exhaust discharged from each exhaust port 5. The exhaust manifold 10 corresponds to the exhaust collecting pipe of the present invention.

  Here, an exhaust pipe 13 through which the exhaust after assembly flows is connected to the cover portion 11. A turbocharger turbine 14 is provided in the middle of the exhaust pipe 13.

  In this embodiment, connecting the exhaust manifold 10 to the cylinder head 3 means that the flange portion 112 formed at the annular opening end portion 111 of the cover portion 11 covering the recess 9 is bolted to the side surface 31 of the cylinder head 3. It is fixed at 15. Further, the sealing performance is improved by welding the flange portion 112 and the side surface 31 of the cylinder head 3 and integrating them.

  According to the present embodiment described above, the exhaust collecting space portion 12 for collecting the exhaust discharged from the exhaust port 5 of the cylinder head 3 can be formed by the concave portion 9 and the cover portion 11. For this reason, a part of the exhaust collecting space portion 12 is formed by the concave portion 9 of the cylinder head 3, and the concave portion 9 is covered with the cover portion 11, so that the concave portion 9 is not exposed to the outside. Therefore, only the cover portion 11 is exposed to the outside air of the member forming the exhaust collecting space portion 12, and the surface area of the portion exposed to the outside air can be reduced. Therefore, since the member forming the exhaust collective space portion 12 is difficult to dissipate heat, the exhaust collective space portion 12 can be prevented from being cooled.

According to this embodiment, since the concave portion 9 is formed in the cylinder head 3, the exhaust port 5 formed in the cylinder head 3 becomes a distance to the inner surface of the concave portion 9, and becomes shorter. Therefore, the heat transfer area to the cylinder head 3 in which the exhaust port 5 is formed can be reduced. Therefore, since heat loss when the exhaust passes through the exhaust port 5 is reduced, it is possible to suppress the exhaust reaching the exhaust collecting space 12 from being cooled. Moreover, since the exhaust port 5 is short, the volume of the exhaust circulation path can be reduced. Therefore, the exhaust energy can be efficiently supplied to the turbine 14 of the downstream turbocharger.

  According to the present embodiment, since the exhaust collecting space portion 12 can be formed only by the recess 9 and the cover portion 11, the shape of the exhaust collecting space portion 12 can be simplified. Therefore, since the number of welding points can be reduced or the number of component parts can be reduced, the cost can be reduced.

  According to the present embodiment, since the exhaust collecting space portion 12 can be formed only by the recess 9 and the cover portion 11, the shape of the exhaust collecting space portion 12 can be made compact. Therefore, it becomes easy to mount the exhaust collecting space portion 12, and a space between the exhaust parts and the peripheral parts can be provided, and heat damage to the peripheral parts can be prevented.

<Example 2>
FIG. 3 is a diagram showing a schematic configuration of the exhaust collecting space portion and its surroundings according to the present embodiment. In the present embodiment, the items described in the above embodiment are denoted by the same reference numerals, description thereof is omitted, and characteristic portions will be described.

  In the present embodiment, the annular opening end 111 of the cover portion 11 of the exhaust manifold 10 is set smaller than the opening 91 of the recess 9 of the cylinder head 3. For this reason, when connecting the exhaust manifold 10 to the cylinder head 3, the annular opening end 111 of the cover part 11 is inserted into the concave part 9, and as shown in FIG. Overlap. And in the site | part where the cover part 11 and the recessed part 9 overlapped, it was made to form the heat insulation layer 16 by an air layer between the cover part 11 and the recessed part 9. FIG. Note that the heat insulating layer 16 is not limited to the one formed by the air layer, but may be one in which a heat insulating material or the like is sandwiched between the cover portion 11 and the concave portion 9.

  In the present embodiment, connecting the exhaust manifold 10 to the cylinder head 3 means that when the cover portion 11 is inserted into the recess 9, the annular opening end portion 111 of the cover portion 11 is welded to the inner surface of the recess 9, The sealing performance is improved by integrating these. Further, a flange portion 112 formed at a position where it abuts on the side surface 31 of the cylinder head 3 is fixed to the side surface 31 of the cylinder head 3 with bolts 15.

  According to the present embodiment described above, the heat insulating layer 16 is formed between the cover portion 11 and the concave portion 9, so that the concave portion 9 exposed to the exhaust collecting space portion 12 is reduced and the cylinder head 3 in which the concave portion 9 is formed. The heat transfer area can be reduced. Therefore, since heat loss when the exhaust exists in the exhaust collecting space 12 is reduced, it is possible to suppress the exhaust of the exhaust collecting space 12 from being cooled.

<Example 3>
In the present embodiment, the items described in the above embodiment are denoted by the same reference numerals, description thereof is omitted, and characteristic portions will be described.

  In this embodiment, the configuration of the recess 9 and the cover portion 11 is the same as that of the first embodiment shown in FIG. In this embodiment, the inner surfaces of the recess 9 and the cover 11 that form the exhaust collecting space 12 are coated with a corrosion-resistant coating material. This corrosion resistant coating material also has a heat insulating property.

Condensed water accumulates in the exhaust collecting space 12, and corrosion may progress on the inner surfaces of the recess 9 and the cover 11. On the other hand, according to the present embodiment, since the inner surface of the concave portion 9 and the cover portion 11 forming the exhaust collecting space portion 12 is coated with a corrosion-resistant coating material, condensed water is formed in the exhaust collecting space portion 12. Even if it accumulates, corrosion of the concave portion 9 and the cover portion 11 can be prevented.

  According to the present embodiment, since the corrosion-resistant coating material further has heat insulation properties, the amount of heat transfer to the cylinder head 3 and the cover portion 11 in which the recesses 9 are formed can be reduced. Therefore, since heat loss when the exhaust exists in the exhaust collecting space 12 is reduced, it is possible to suppress the exhaust of the exhaust collecting space 12 from being cooled.

<Example 4>
FIG. 4 is a diagram showing a schematic configuration of the exhaust collecting space portion and its surroundings according to the present embodiment. In the present embodiment, the items described in the above embodiment are denoted by the same reference numerals, description thereof is omitted, and characteristic portions will be described.

  In the present embodiment, when the exhaust manifold 10 is connected to the cylinder head 3, the gasket 17 interposed between the concave portion 9 and the cover portion 11 is provided. The gasket 17 is a semicircular member having a cross section that covers the inner surface of the recess 9 except for the region of the exhaust port 5. And this gasket 17 is integrated with the heat shield.

  In this embodiment, when the exhaust manifold 10 is connected to the cylinder head 3, the gasket 17 is attached to the inner surface of the recess 9 to cover the inner surface of the recess 9. The flange portion 112 formed at the annular opening end portion 111 of the exhaust manifold 10 is fixed to the side surface 31 of the cylinder head 3 with the bolt 15 together with the flange portion of the gasket 17. In this embodiment, the gasket 17 is interposed to improve the sealing performance. Therefore, the flange portion 112 and the gasket 17 or the side surface 31 of the cylinder head 3 and the gasket 17 are not welded and fixed by the bolt 15. To do.

  According to the present embodiment described above, the gasket 17 is interposed between the concave portion 9 and the cover portion 11, so that the sealing property between the concave portion 9 and the cover portion 11 can be improved without requiring welding or the like. For this reason, since the number of welding points can be reduced, cost reduction can be achieved.

  According to this embodiment, the gasket 17 is integrated with the heat shield plate, and the gasket 17 has a heat insulating property, so that the amount of heat transfer to the gasket 17 can be reduced. Thereby, the amount of heat transfer to the cylinder head 3 having the recess 9 covered with the gasket 17 can be reduced. Therefore, since heat loss when the exhaust exists in the exhaust collecting space 12 is reduced, it is possible to suppress the exhaust of the exhaust collecting space 12 from being cooled.

<Example 5>
FIG. 5 is a diagram showing a schematic configuration of the exhaust collecting space portion and its surroundings according to the present embodiment. In the present embodiment, the items described in the above embodiment are denoted by the same reference numerals, description thereof is omitted, and characteristic portions will be described.

  In this embodiment, the configuration of the recess 9 and the cover portion 11 is the same as that of the first embodiment shown in FIG. In this embodiment, the annular protrusion 18 that protrudes from the peripheral edge of the opening 51 of the exhaust port 5 on the inner surface of the recess 9 and extends the length of the exhaust port 5 is provided. The annular protrusion 18 is provided by burring when the cylinder head 3 is formed.

  According to the present embodiment described above, the length of the exhaust port 5 can be extended by the annular protrusion 18. Therefore, the intake and exhaust efficiency can be improved by using exhaust pulsation due to strong blowdown from the exhaust port 5 extended by the annular protrusion 18.

In the above embodiment, a diesel engine is taken as an example of the internal combustion engine 1. However, it is not limited to this. You may employ | adopt this invention about a gasoline engine.

  In addition, the structure of the said Example can be combined as much as possible. Further, the exhaust device for an internal combustion engine according to the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the gist of the present invention.

1 is a diagram illustrating a schematic configuration of an internal combustion engine and an exhaust system thereof according to Embodiment 1. FIG. FIG. 3 is a diagram illustrating a schematic configuration of a recess according to the first embodiment. FIG. 6 is a diagram illustrating a schematic configuration of an exhaust collecting space portion and its surroundings according to a second embodiment. FIG. 6 is a diagram illustrating a schematic configuration of an exhaust collecting space portion and its surroundings according to a fourth embodiment. FIG. 9 is a diagram illustrating a schematic configuration of an exhaust collecting space portion and its surroundings according to a fifth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 3 Cylinder head 4 Intake port 5 Exhaust port 6 Intake valve 7 Exhaust valve 8 Fuel injection valve 9 Recess 10 Exhaust manifold 11 Cover part 12 Exhaust collecting space part 13 Exhaust pipe 14 Turbine 15 Bolt 16 Heat insulation layer 17 Gasket 18 Annular protrusion 31 Cylinder head side surface 51 Exhaust port opening 91 Recess opening 111 Cover opening annular opening 112 Flange

Claims (7)

In the cylinder head, a concave portion in which openings of a plurality of exhaust ports are formed on the inner surface;
A cover part that forms an exhaust collecting space part that collects exhaust gas between the concave part in the exhaust collecting pipe connected to the cylinder head;
An exhaust device for an internal combustion engine, comprising:   An annular opening end portion of the cover portion is smaller than an opening portion of the recessed portion, and when the exhaust collecting pipe is connected to the cylinder head, the annular opening end portion of the cover portion is inserted into the recessed portion, 2. The exhaust system for an internal combustion engine according to claim 1, wherein a heat insulating layer is formed between the cover portion and the concave portion at a portion where the cover portion and the concave portion overlap each other.   The exhaust system for an internal combustion engine according to claim 1 or 2, wherein surfaces of the concave portion and the cover portion forming the exhaust collecting space portion are coated with a corrosion-resistant coating material.   The exhaust device for an internal combustion engine according to claim 3, wherein the corrosion-resistant coating material has a heat insulating property.   2. The exhaust system for an internal combustion engine according to claim 1, further comprising a gasket interposed between the concave portion and the cover portion when the exhaust collecting pipe is connected to the cylinder head.   The exhaust device for an internal combustion engine according to claim 5, wherein the gasket is integrated with a heat shield.   The exhaust of the internal combustion engine according to any one of claims 1 to 6, further comprising an annular protrusion that protrudes from a peripheral edge of the opening of the exhaust port on an inner surface of the recess and extends the length of the exhaust port. apparatus.

Images