JP4655033B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine, and more particularly to an internal combustion engine having an intake port for taking in intake air.

Conventionally, internal combustion engines have been disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-204796 (Patent Document 1), Japanese Patent Application Laid-Open No. 2003-56399 (Patent Document 2), Japanese Patent Application Laid-Open No. 2005-256678 (Patent Document 3), No. 303164 (Patent Document 4) and JP-A-6-185404 (Patent Document 5).
JP 2004-204796 A JP 2003-56399 A JP 2005-256678 A JP-A-4-303164 JP-A-6-185404

Patent Document 1 discloses a technique for inserting and fixing a resin heat insulating material in an intake port.
In Patent Document 2, a cooling unit that allows heat exchange between the intake port and the coolant via the intake port wall is formed in the region of the intake port that comes into contact with the gas blown back from the combustion chamber during the intake stroke, A structure of an intake port is disclosed in which a heat insulating portion that blocks heat exchange between the intake port and the coolant is provided between the end portion and the inlet portion of the intake port.

  Patent Document 3 discloses a technique in which a liner is installed in an intake port, and a thermal insulation air layer is formed between the head and the liner.

  Patent Document 4 discloses a technique in which up to the forked portion of the intake port is configured with a ceramic port liner.

  Patent Document 5 discloses a technique for fixing an exhaust port liner to an exhaust manifold.

However, the conventional technique has a problem that the intake resistance is high.
Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide an internal combustion engine having an intake port structure capable of reducing intake resistance.

According to the present invention, an internal combustion engine includes a cylinder head that constitutes an intake port, and a heat insulating member that is embedded in the cylinder head and connected to an intake manifold and constitutes the intake port. The heat insulating member has a cylindrical shape, extends from the intake manifold to at least a branch portion of the intake port, the branch portion has an acute angle, and the heat insulating member has a thermal conductivity smaller than that of the cylinder head. An internal combustion engine has an injection device that injects fuel into an intake port, and a portion of a heat insulating member to which fuel injected from the injection device is directly injected is in contact with a cylinder head without interposing an air layer.
In this case, the portion where the fuel is directly injected is warmed by the cylinder head, and fuel vaporization can be promoted.

  In the internal combustion engine configured as described above, the intake resistance can be reduced because the branch portion forms an acute angle.

  Preferably, an air layer is interposed between the heat insulating member and the cylinder head. In this case, the heat insulation effect can be further enhanced.

Preferably, the cylinder head is provided with a hole, the inner diameter of the hole is constant in the axial direction of the hole, and the heat insulating member is inserted into the hole. In this case, the assembling property of the heat insulating member can be improved.

  Preferably, the hole and the intake port of the cylinder head connected to the hole are formed by casting using a core. In this case, the hole and the intake port can be manufactured at a time.

  Preferably, the heat insulating member has an extending portion extending from the cylinder head toward the intake manifold, and the extending portion fits into the intake port of the intake manifold. In this case, the intake manifold can be reliably positioned.

  According to the present invention, an internal combustion engine capable of reducing intake resistance can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. In addition, the embodiments can be combined.

(Embodiment 1)
1 is a cross-sectional view of an internal combustion engine according to Embodiment 1 of the present invention. Referring to FIG. 1, an engine as an internal combustion engine according to Embodiment 1 of the present invention has a cylinder block 100 and a cylinder head 30 provided on cylinder block 100. A piston 110 is inserted into the bore of the cylinder block 100. The upper part of the piston 110 is in the combustion chamber 111. A cylinder head 30 is installed on the cylinder block 100. The cylinder head 30 has an intake port 32 and an exhaust port 221, and the intake port 32 is a path for introducing air-fuel mixture or air into the combustion chamber 111. The exhaust port 221 releases exhaust gas from the combustion chamber 111 to the outside of the vehicle. It is a route to do.

  The internal combustion engine may be a diesel engine as well as a gasoline engine. Further, the arrangement of each piston 110 may be a series type, a V type, a horizontally opposed type, or a W type. Furthermore, it may be a rotary engine as well as a reciprocating engine.

  A hole 31 is provided in the cylinder head 30, and the sleeve member 20 made of a heat insulating member is disposed in the hole 31. The sleeve member 20 is made of a material having a lower thermal conductivity than the material constituting the cylinder head 30. For example, when the cylinder head 30 is made of aluminum, the sleeve member 20 is made of ceramic or resin. An intake port 21 is provided in the sleeve member 20, and the intake port 21 branches off at an edge portion 25 to form two intake ports. One intake port 22 is connected to an intake port 32 of the cylinder head 30. Yes. The flange portion 121 provided on the outer periphery of the sleeve member 20 is relatively thicker than other portions, and the strength is secured at this portion. An air layer 40 is interposed between the sleeve member 20 and the hole 31 of the cylinder head 30. By interposing the air layer 40, heat transfer between the sleeve member 20 and the cylinder head 30 can be suppressed.

  Intake manifold 10 is connected to cylinder head 30. The intake port 11 in the intake manifold 10 is connected to the intake port 21 of the sleeve member 20. The intake manifold 10 is in contact with the sleeve member 20.

  FIG. 2 is a plan view of the sleeve member viewed from the direction indicated by the arrow II in FIG. Referring to FIG. 2, the sleeve member 20 has a shape that increases in diameter as it approaches the intake ports 32 and 33. However, the outer diameter of the flange portion 121 is substantially constant, and the flange portion 121 is inserted into the hole 31. The intake port 21 is a single cylindrical member on the intake manifold side, but branches into two at the edge portion 25. The two intake ports 22 and 32 are respectively connected to the intake ports 32 and 33 on the cylinder head side. It is connected. The amount of air interposed between the cylinder head 30 and the sleeve member 20 is large on the intake manifold side and small on the intake ports 32 and 33 side. The edge portion 25 is formed of a heat insulating member that constitutes the sleeve member 20, and its tip end portion is formed at an acute angle.

  FIG. 3 is an enlarged view of a portion surrounded by III in FIG. Referring to FIG. 3, the intersection of the side walls of intake ports 22 and 23 is edge portion 25, which forms an acute angle θ. The edge portion 25 may be configured by polishing, for example. By forming the edge portion 25 at an acute angle, it is possible to suppress the occurrence of resistance in the flow of intake air at the branch portion. Thereby, intake resistance can be reduced and more air or air-fuel mixture can be introduced into the combustion chamber. Further, the pumping loss can be reduced.

  FIG. 4 is a side view of the sleeve member viewed from the direction indicated by the arrow IV in FIG. Referring to FIG. 4, the sleeve member 20 has a substantially constant outer diameter D. The flange portions 121 of the sleeve member 20 are positioned at substantially equal intervals, and each has a diameter D. This diameter D is substantially equal to the inner diameter of the hole 31. In this embodiment, an example in which the sleeve member 20 has substantially the same diameter is shown. However, the present invention is not limited to this, and the diameter of the sleeve member 20 may become smaller or larger as it approaches the intake port 32. May be. Further, the diameter of the sleeve member 20 may change continuously, or the sleeve member 20 may have a shape in which the outer diameter changes stepwise.

  The sleeve member 20 may have a screw shape, and a thread groove that meshes with the screw may be provided in the hole 31 so that the sleeve member 20 and the hole 31 are screwed together. In that case, the flange portion 121 has a circular shape.

  FIG. 5 is a front view of the flange portion viewed from the direction indicated by the arrow V in FIG. Referring to FIG. 5, flange portion 121 has an elliptical shape. In addition, the flange part 121 does not need to be elliptical, and may be another curved shape such as a circular shape. Furthermore, it may be a polygonal shape such as a triangle or a quadrangle.

  That is, the internal combustion engine includes a cylinder head 30 that constitutes the intake ports 32 and 33, and a sleeve member 20 that is embedded in the cylinder head 30 and connected to the intake manifold 10 as a heat insulating member that constitutes the intake ports 21, 22, and 23. With. The sleeve member 20 is cylindrical and extends from the intake manifold 10 to the edge portion 25. The edge portion 25 forms an acute angle θ. The sleeve member 20 has a smaller thermal conductivity than the cylinder head 30. That is, the sleeve member 20 only needs to be made of a heat insulating member up to at least the edge portion 25, and the tip thereof may be made of a metal such as aluminum.

  An air layer 40 is interposed between the sleeve member 20 and the cylinder head 30. The cylinder head 30 is provided with a hole 31 having a constant inner diameter, and the sleeve member 20 is inserted into the hole 31.

  In the sleeve member 20 configured as described above, an edge portion 25 that is a branch portion of the intake port 21 is formed of a heat insulating material. Therefore, it is possible to provide an edge portion 25 that is acute and sharp. In addition, when a branch is normally comprised with aluminum, since stress concentration by combustion pressure or cold heat generate | occur | produces in a branch part, it is necessary to attach R. On the other hand, in the present invention, since the branch portion is configured with an acute angle, the ventilation resistance of the edge portion 25 that is the branch portion can be reduced.

(Embodiment 2)
6 is a cross-sectional view for illustrating a method of manufacturing an intake port according to the second embodiment of the present invention. In the manufacturing method shown in FIG. 6, the hole 31 is formed by casting using the core 220 and the mold 210. An intake port 32 is formed simultaneously with the hole 31. The other part of the cylinder head 30 is also formed by casting.

  In the internal combustion engine according to the second embodiment configured as described above, it is possible to configure the hole 31 and insert the sleeve member 20 into the hole 31 without adding a machining process. In addition, by forming the intake port 32 and the hole 31 integrally, the variation in the level difference between the intake port 32 and the hole 31 can be reduced.

(Embodiment 3)
FIG. 7 is a cross-sectional view of an internal combustion engine according to Embodiment 3 of the present invention. Referring to FIG. 7, in the internal combustion engine according to the third embodiment of the present invention, an injector 80 as an injection device is provided in intake manifold 10, and the injection of fuel 81 injected from injector 80 is injected. The region 123 is directly mounted in the hole 31 of the cylinder head 30. That is, the air layer 40 in the portion where the fuel adheres is eliminated. Thereby, the portion of the sleeve member 20 to which the fuel 81 injected from the injector 80 is directly injected is in contact with the cylinder head 30 without the air layer 40 interposed. Thereby, vaporization of fuel can be improved and emission performance can be improved. Note that when the wall temperature is low, the vaporization of the attached fuel deteriorates and the emission performance decreases. Moreover, it is also possible to obtain the same effect by combining insert molding with other materials having a good heat transfer coefficient at the site where the fuel adheres.

(Embodiment 4)
FIG. 8 is a cross-sectional view of an internal combustion engine according to Embodiment 4 of the present invention. Referring to FIG. 8, in the internal combustion engine according to the fourth embodiment of the present invention, sleeve member 20 has an extended portion 124 extending toward intake manifold 10, and extended portion 124 fits into intake manifold 10. Matching. The intake manifold 10 also receives a seal member 12 to maintain the airtightness between the intake manifold 10 and the cylinder head 30. That is, in this embodiment, the sleeve member 20 has an extending portion 124 that extends from the cylinder head 30 toward the intake manifold 10, and the intake port 11 of the intake manifold 10 fits into the extending portion 124.

  In this embodiment configured as described above, the intake manifold 10 side of the sleeve member 20 is held by the intake manifold 10 and does not contact the cylinder head 30. Thereby, the heat insulation effect can be further improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a cross-sectional view of an internal combustion engine according to Embodiment 1 of the present invention. It is the top view of the sleeve member seen from the direction shown by the arrow II in FIG. It is a figure which expands and shows the part enclosed by III in FIG. FIG. 4 is a side view of the sleeve member viewed from a direction indicated by an arrow IV in FIG. 2. It is a front view of the flange part seen from the direction shown by the arrow V in FIG. It is sectional drawing for demonstrating the manufacturing method of the intake port according to Embodiment 2 of this invention. It is sectional drawing of the internal combustion engine according to Embodiment 3 of this invention. It is sectional drawing of the internal combustion engine according to Embodiment 4 of this invention.

Explanation of symbols

  10 Intake manifold, 11, 21, 22, 23, 32, 33 Intake port, 20 sleeve member, 25 edge portion, 30 cylinder head, 31 holes, 100 cylinder block.

Claims (5)

A cylinder head constituting an intake port;
A heat insulating member that is embedded in the cylinder head and connected to the intake manifold, and constitutes an intake port;
The heat insulating member is a tubular, extends to the branch portion of at least the intake port from the intake manifold, the branch portion at an acute angle, said heat insulating member have a smaller thermal conductivity than the cylinder head,
An internal combustion engine further comprising an injection device for injecting fuel into the intake port, wherein the portion of the heat insulating member directly injected with the fuel injected from the injection device is in contact with the cylinder head without an air layer interposed organ.   The internal combustion engine according to claim 1, wherein an air layer is interposed between the heat insulating member and the cylinder head. The internal combustion engine according to claim 1, wherein the cylinder head is provided with a hole, an inner diameter of the hole is constant in an axial direction of the hole, and the heat insulating member is inserted into the hole. The internal combustion engine according to claim 3 , wherein the hole and the intake port of the cylinder head connected to the hole are manufactured by casting using a core. The thermal insulating member has an extending portion extending toward the intake manifold from the cylinder head, the extending portion fitted to the intake port of the intake manifold, according to any one of claims 1 4 Internal combustion engine.

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