Internal combustion engine

Abstract

To properly supply intake air while suppressing a rise in temperature of the intake air inside an intake manifold.SOLUTION: An internal combustion engine includes: a cylinder head 14 including a suction port; an intake manifold 20 having an opening face 22 connected to an opening face 14a of the cylinder head 14 to lead intake air to the suction port via the opening face 22; and a heat shield film 80 positioned between the opening face 14a and the opening face 22 and made of a material having heat shielding property.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an internal combustion engine. [Background technology]

[0002] In the following Patent Document 1, an adapter with low thermal conductivity is provided between an intake manifold and a cylinder head in order to suppress a rise in temperature of the intake air sent to each cylinder of an internal combustion engine via an intake port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7310958 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if a thick adapter is provided, the space through which the intake air passes increases by the thickness of the adapter, which changes the flow of intake air from the intake manifold to the cylinder head. This changes the amount of intake air flowing into each cylinder, and the combustion mode of the intake air inside the cylinders, which may result in a decrease in combustion efficiency.

[0005] The present invention has been made in consideration of these points, and has an object to appropriately supply intake air while suppressing a rise in the temperature of the intake air in the intake manifold. [Means for solving the problem]

[0006] In one aspect of the present invention, an internal combustion engine is provided comprising: a cylinder head having an intake port; an intake manifold having a second opening surface connected to a first opening surface of the cylinder head and directing intake air to the intake port via the second opening surface; and a heat-shielding film positioned between the first opening surface and the second opening surface and made of a material having heat-shielding properties.

[0007] The heat shielding film may be formed by applying the material to the second opening surface and may be in contact with the first opening surface.

[0008] The heat shielding film may be formed by applying the material to the first opening surface and may be in contact with the second opening surface.

[0009] In addition, a flow path through which cooling water flows may be provided within the cylinder head, the temperature of the cooling water may be higher than the temperature of the intake air in the intake manifold, and the heat-shielding film may block heat transfer of the cooling water to the intake manifold.

[0010] The fuel cell may further include a seal member provided in an annular shape around the opening of the second opening surface, and the heat shielding film may be positioned around the seal member. The thickness of the heat insulating film may be smaller than the thickness of the sealing member.

[0011] The heat shielding film may be made of a resin material having heat shielding properties. The heat insulating film may be made of a metal material having heat insulating properties. Effect of the Invention

[0012] According to the present invention, it is possible to suppress a rise in the temperature of the intake air in the intake manifold, while appropriately supplying the intake air. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of an internal combustion engine 10 according to one embodiment. [Diagram 2] 2 is a schematic diagram showing the configuration of a connection portion between a cylinder head 14 and an intake manifold 20. FIG. [Diagram 3] FIG. 3 is a view taken along the line AA in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view of FIG. [Diagram 5]FIG. 4 is a schematic diagram showing the relationship between intake air temperature and fuel efficiency. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <Configuration of an internal combustion engine> 1 is a schematic diagram showing a configuration of an internal combustion engine 10 according to one embodiment. Here, the internal combustion engine 10 is mounted on a vehicle 1, but is not limited thereto, and may be mounted on a ship, for example. The vehicle 1 is, for example, a truck. As shown in FIG. 1, the vehicle 1 has the internal combustion engine 10, an intake passage 30, an exhaust passage 50, and an EGR passage 60.

[0015] The internal combustion engine 10 is, for example, a diesel engine. The internal combustion engine 10 generates power by burning and expanding a fuel mixture of intake air in a combustion chamber 11. The internal combustion engine 10 has a cylinder block 12, a cylinder head 14, an intake manifold 20, and an exhaust manifold 25.

[0016] A cylinder 12a is formed in the cylinder block 12, and the cylinder 12a houses a reciprocating piston 13. Although only one cylinder 12a is shown in Fig. 1, a plurality of cylinders 12a are arranged in the depth direction of the paper surface of Fig. 1.

[0017] The cylinder head 14 covers an upper part of the cylinder block 12. Provided within the cylinder head 14 are an intake port 15a, an exhaust port 15b, an intake valve 16a, an exhaust valve 16b, an injector 17, and a cooling water passage 18 (FIG. 2).

[0018] The intake port 15a introduces intake air into the combustion chamber 11. The exhaust port 15b discharges exhaust air from the combustion chamber 11. The intake valve 16a adjusts the inflow of intake air into the combustion chamber 11 by opening and closing the intake port 15a. The exhaust valve 16b adjusts the outflow of exhaust air from the combustion chamber 11 by opening and closing the exhaust port 15b. The injector 17 injects fuel into the combustion chamber 11. The cooling water passage 18 is a passage through which cooling water flows to cool the internal combustion engine 10. The temperature of the cooling water is higher than the temperature of the intake air in the intake manifold 20. As an example, the temperature of the cooling water is 80°C and the temperature of the intake air is 40°C.

[0019] The intake manifold 20 is a manifold for distributing intake air to the combustion chambers 11 of each cylinder 12a of the internal combustion engine 10. The intake manifold 20 is connected to the intake port 15a of the cylinder head 14. A heat insulating film 80 (see FIG. 2) is provided at the connection portion between the intake manifold 20 and the cylinder head 14, as will be described in detail later.

[0020] The exhaust manifold 25 is a collecting pipe that collects exhaust gas discharged from the combustion chambers 11 of the cylinders 12a of the internal combustion engine 10. The exhaust manifold 25 is connected to the exhaust ports 15b of the cylinder head 14.

[0021] The intake passage 30 is a flow path through which intake air (air) flows to be introduced into the internal combustion engine 10. The intake passage 30 is connected to the intake manifold 20. The air flowing through the intake passage 30 is introduced into each cylinder 12a of the internal combustion engine 10 via the intake manifold 20.

[0022] The exhaust passage 50 is a flow path that guides exhaust gas from the internal combustion engine 10 to the atmosphere. The exhaust passage 50 is connected to the exhaust manifold 25. The exhaust gas discharged from the combustion chamber 11 of each cylinder 12a of the internal combustion engine 10 flows into the exhaust passage 50 via the exhaust manifold 25.

[0023] The EGR passage 60 connects the exhaust passage 50 and the intake manifold 20. The EGR passage 60 is a recirculation passage that recirculates a portion of the exhaust gas (also called EGR gas) to the internal combustion engine 10 via the intake manifold 20. The EGR gas is mixed with air in the intake manifold 20. The EGR passage 60 may be provided with an EGR valve that adjusts the flow rate of the EGR gas.

[0024] <Configuration of the Connection Between the Cylinder Head 14 and the Intake Manifold 20> Fig. 2 is a schematic diagram showing the configuration of a connection portion between the cylinder head 14 and the intake manifold 20. Fig. 3 is a view taken along the line AA in Fig. 2. Fig. 4 is a cross-sectional view taken along the line BB in Fig. 3. For ease of explanation, the intake passage 30 and the EGR passage 60 are omitted in Fig. 2.

[0025] 2, the cylinder head 14 has an opening surface 14a connected to the intake manifold 20. An opening through which air from the intake manifold 20 passes is formed in the opening surface 14a.

[0026] 2, a flow passage 21 through which the intake air flows is provided within the intake manifold 20. The flow passage 21 is connected to the intake port 15a of the cylinder head 14. The intake manifold 20 also has an opening surface 22 that is connected to the opening surface 14a of the cylinder head 14.

[0027] The opening surface 22 has an opening 22a through which air passes toward the cylinder head 14. As shown in Fig. 3, the opening 22a is located at the center of the opening surface 22. The opening 22a is located at the tip of the flow passage 21 (Fig. 2). Therefore, the intake manifold 20 guides the intake air to the intake port 15a of the cylinder head 14 through the opening surface 22. In this embodiment, the opening surface 14a corresponds to the first opening surface, and the opening surface 22 corresponds to the second opening surface.

[0028] The opening surface 14a of the cylinder head and the opening surface 22 of the intake manifold 20 are not in direct contact with each other. In this embodiment, as shown in Figs. 2 to 4, a seal member 70 and a heat shielding film 80 are provided between the opening surface 14a and the opening surface 22. The seal member 70 and the heat shielding film 80 are in contact with both the opening surface 14a and the opening surface 22.

[0029] The seal member 70 is located between the opening surface 22 of the intake manifold 20 and the opening surface 14a of the cylinder head 14, and seals the connection portion between the opening surface 22 and the opening surface 14a. The seal member 70 is, for example, a rubber packing.

[0030] 3, the seal member 70 is provided in an annular shape around the opening 22a of the opening surface 22 of the intake manifold 20. The seal member 70 is inserted into a recess 23 (FIG. 4) that is provided in an annular shape around the opening 22a in the opening surface 22.

[0031] The heat shielding film 80 is a thin film made of a material having heat shielding properties. The temperature of the cylinder head 14 to which the heat of combustion in the combustion chamber 11 is transferred is higher than the temperature of the intake manifold 20. However, since the heat shielding film 80 is provided between the opening surface 14a and the opening surface 22, the transfer of heat from the opening surface 14a of the cylinder head 14 to the opening surface 22 of the intake manifold 20 can be blocked. This can suppress the increase in temperature of the opening surface 22 of the intake manifold 20, so that the temperature of the intake air in the intake manifold 20 can be suppressed from increasing. In this embodiment, the seal member 70 is made of rubber and has heat shielding properties. Therefore, the heat transfer can be effectively suppressed by the heat shielding film 80 and the seal member 70. The heat shielding film 80 is for suppressing the transfer of heat from the opening surface 14a of the cylinder head 14 to the opening surface 22 of the intake manifold 20, and can also be said to be a heat insulating film having heat insulating properties. Furthermore, the heat shielding film 80 can also be said to be a thin film having both heat insulating and heat insulating functions.

[0032] As described above, cooling water circulates inside the cylinder head 14, and the temperature of the cooling water is higher than the surface temperature of the intake manifold 20 and the temperature of the intake air inside the intake manifold 20. For this reason, there is a risk that the heat of the cooling water will transfer to the intake air inside the intake manifold 20. In contrast, when the heat shielding film 80 is provided as in this embodiment, the heat shielding film 80 blocks the transfer of heat from the cooling water to the intake manifold 20. This makes it possible to prevent the intake air inside the intake manifold 20 from rising in temperature due to the heat of the cooling water.

[0033] FIG. 5 is a schematic diagram showing the relationship between intake air temperature and fuel efficiency. The horizontal axis of the graph in FIG. 5 indicates the temperature in the intake manifold 20, with the temperature increasing toward the right. The vertical axis of the graph indicates fuel efficiency, with fuel efficiency worsening toward the top. As can be seen from the graph, the higher the intake air temperature, the worse the fuel efficiency (the lower the combustion efficiency). This is because as the intake air temperature increases, the density of the intake air decreases, and the amount of intake air taken into the combustion chamber 11 decreases. In this embodiment, by providing the heat shield film 80, the temperature rise of the intake air in the intake manifold 20 can be suppressed, and therefore the decrease in combustion efficiency can be suppressed.

[0034] In addition, since the heat shielding film 80 is a thin film, it does not affect the flow of intake air (air and EGR gas) flowing from the intake manifold 20 to the cylinder head 14. Unlike this embodiment, if a thick plate is sandwiched between the opening surface 22 and the opening surface 14a, the space through which the intake air flows becomes larger, and the flow of the intake air is more likely to change. Specifically, the flow of the intake air along the inner wall of the intake manifold 20 and the flow of the intake air flowing through the center of the intake manifold 20 change. In addition, if the plate is provided, it may affect the mixing of the air and EGR gas in the intake manifold 20, which may adversely affect the combustion of the intake air in the combustion chamber 11.

[0035] In order to achieve a thinner heat shielding film 80, the heat shielding film 80 is formed by applying a material (coating material) to the opening surface 22 of the intake manifold 20. The heat shielding film 80 is in contact with the opening surface 14a of the cylinder head 14. By forming the heat shielding film 80 with a coating material in this manner, the distance between the opening surface 22 of the intake manifold 20 and the opening surface 14a of the cylinder head 14 can be made smaller than when a thick part such as a plate is provided, so that the space through which the intake air flows can be prevented from becoming large even when the heat shielding film 80 is provided.

[0036] The heat shielding film 80 is applied around the opening 22a on the opening surface 22. Specifically, as shown in Fig. 3, the heat shielding film 80 is applied around the sealing member 70. More specifically, the heat shielding film 80 is applied in an annular shape so as to surround the sealing member 70. The width of the heat shielding film 80 is greater than the width of the sealing member 70. As a result, the heat shielding film 80 is formed over a wide range of the opening surface 22, making it easier to block heat transfer from the opening surface 14a to the opening surface 22.

[0037] The thickness of the heat shielding film 80 is smaller than the thickness of the seal member 70, as shown in FIG. 4. The thickness of the heat shielding film 80 is 100 μm here. Since the heat shielding film 80 is thin, the flow of the intake air (air and EGR gas) flowing from the intake manifold 20 to the cylinder head 14 is less likely to change. Furthermore, since the heat shielding film 80 is thin, the influence of the mixture of the air and EGR gas in the intake manifold 20 is also small. The manner in which the intake air is burned in the combustion chamber 11 of each cylinder 12a of the internal combustion engine 10 is not changed, and it is possible to prevent a decrease in the combustion efficiency. The thickness of the heat shielding film 80 is not limited to 100 μm, and may be within a range of, for example, 50 μm to 150 μm.

[0038] The heat shielding film 80 is made of a resin material having at least one of heat shielding and heat insulating properties. For example, the heat shielding film 80 is made of polyphenylene sulfide (PPS). Polyphenylene sulfide is a synthetic resin belonging to crystalline thermoplastic resins, which has a simple linear structure in which benzene rings and sulfur atoms are alternately bonded. When the heat shielding film 80 is made of the above-mentioned resin material, it can effectively block heat transfer from the cylinder head 14 to the intake manifold 20. Note that the heat shielding film 80 may be made of a resin material other than polyphenylene sulfide as long as it has heat shielding properties (heat insulating properties).

[0039] (Modification) In the above, the heat shielding film 80 is applied to the opening surface 22 of the intake manifold 20 and is in contact with the opening surface 14a of the cylinder head 14, but is not limited to this. For example, the heat shielding film 80 may be formed by applying a coating material to the opening surface 14a of the cylinder head 14 and be in contact with the opening surface 22 of the intake manifold 20. Even in this case, the heat shielding film 80, which is a thin film, can be formed between the opening surface 22 and the opening surface 14a.

[0040] In the above description, the heat shielding film 80 is made of a resin material having heat shielding properties, but the material is not limited to this. The heat shielding film 80 may be made of a metal material having heat shielding properties. For example, the heat shielding film 80 is made of zirconia. Zirconia is a general term for zirconium oxide, which is an oxide of zirconium (Zr). In this case as well, the heat shielding film 80 can effectively block heat transfer from the cylinder head 14 to the intake manifold 20.

[0041] In the above, the heat shielding film 80 is located outside the seal member 70 at the opening surface 22, but this is not limited to this. For example, the heat shielding film 80 may be located between the opening 22a and the seal member 70 at the opening surface 22. Also, the heat shielding film 80 may be formed on the outer and inner sides of the seal member 70 at the opening surface 22. In this case, since the heat shielding film 80 is located over a wide range of the opening surface 22, it is possible to more effectively block heat transfer from the cylinder head 14 to the intake manifold 20.

[0042] <Effects of this embodiment> The internal combustion engine 10 of the embodiment described above has a heat insulating film 80 that is located between the opening surface 14a of the cylinder head 14 and the opening surface 22 of the intake manifold 20, which are connected to each other, and is made of a material having heat insulating properties. By providing the heat shielding film 80, it is possible to block heat transfer from the opening surface 14a of the cylinder head 14, which has a high temperature, to the opening surface 22 of the intake manifold 20, thereby suppressing a rise in the temperature of the intake air in the intake manifold 20. Furthermore, since the heat shielding film 80 is thin, it does not adversely affect the flow of intake air from the intake manifold 20 to the cylinder head 14, so that the intake air can be appropriately supplied to the combustion chamber 11.

[0043] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0044] 10 Internal combustion engine 14 Cylinder head 14a Opening surface 15a Intake port 20 Intake manifold 22 Opening surface 22a opening 70 Sealing material 80 Heat shielding film

Claims

1. a cylinder head having an intake port; an intake manifold having a second opening surface connected to the first opening surface of the cylinder head and directing intake air to the intake port through the second opening surface; a heat shielding film located between the first opening surface and the second opening surface and made of a material having heat shielding properties; An internal combustion engine comprising:

2. the heat shielding film is formed by applying the material to the second opening surface and is in contact with the first opening surface; 2. The internal combustion engine of claim 1.

3. The heat shielding film is formed by applying the material to the first opening surface and is in contact with the second opening surface.

2. The internal combustion engine of claim 1.

4. A flow passage through which cooling water flows is provided in the cylinder head, the temperature of the cooling water is higher than the temperature of the intake air in the intake manifold; The heat-shielding film blocks heat transfer of the cooling water to the intake manifold.

2. The internal combustion engine of claim 1.

5. a seal member provided annularly around the opening of the second opening surface, The heat shielding film is positioned around the sealing member.

2. The internal combustion engine of claim 1.

6. The thickness of the heat insulating film is smaller than the thickness of the sealing member.

6. An internal combustion engine according to claim 5.

7. The heat-shielding film is made of a resin material having heat-shielding properties.

2. The internal combustion engine of claim 1.

8. The heat shielding film is made of a metal material having heat shielding properties.

2. The internal combustion engine of claim 1.

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