Internal combustion engine

Abstract

Provided is an internal combustion engine capable of suppressing damage to a supercharger. The internal combustion engine includes: an internal combustion engine main body; a supercharger connected to the internal combustion engine main body; and an intake device connected to the internal combustion engine main body, the intake device having: a first flow path through which fresh gas is introduced to the supercharger; and a second flow path through which blow-by gas from the internal combustion engine main body flows, the second flow path extending adjacent to the first flow path, the second flow path merging with the first flow path from the oblique rear side of the direction in which the fresh gas flows at one end, and a space being provided inside a partition wall that separates the first flow path and the second flow path from each other.

Description

Technical Field

[0001] This invention relates to internal combustion engines. Background Technology

[0002] Regarding internal combustion engines, for example, Patent Document 1 describes the introduction of leaked gas into the intake passage connected to the turbocharger via an inlet passage.

[0003] [Existing Technical Documents]

[0004] [Patent Literature]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2024-41416

[0006] [The problem the invention aims to solve]

[0007] When leaked gas flows from the inlet passage into the intake passage, it is rapidly cooled by the low-temperature fresh gas flowing within the intake passage. As a result, the moisture in the leaked gas crystallizes, forming a large number of ice crystals. These ice crystals may flow into the downstream turbocharger and damage the impeller and other components. Summary of the Invention

[0008] Therefore, the present invention was made in view of the above-mentioned problems, and its object is to provide an internal combustion engine capable of suppressing damage to the turbocharger.

[0009] [Methods used to solve problems]

[0010] The internal combustion engine of the present invention comprises: an internal combustion engine body; a turbocharger connected to the internal combustion engine body; and an intake device connected to the internal combustion engine body, the intake device having: a first flow path for introducing fresh gas into the turbocharger; and a second flow path for allowing leakage gas from the internal combustion engine body to flow, the second flow path extending adjacent to the first flow path, the second flow path merging with the first flow path at one end obliquely rearward from the direction of the fresh gas flow, and a space provided inside a partition wall separating the adjacent first flow path and the second flow path.

[0011] In the aforementioned internal combustion engine, the partition wall may also have a curved surface at one end, the curved surface bulging out toward the second flow path side and bending toward the first flow path side.

[0012] In the aforementioned internal combustion engine, the second flow path may also have a connecting portion, which is connected to the vent of the leaking gas. The vent is located in the cover of the internal combustion engine, and the connecting portion has a throttling orifice.

[0013] In the aforementioned internal combustion engine, there may also be a heat insulation component, which is disposed in the space.

[0014] In the aforementioned internal combustion engine, a heating unit may also be provided, which is disposed in the space and heats the second flow path.

[0015] [Invention Effects]

[0016] According to the present invention, damage to the turbocharger of an internal combustion engine can be suppressed. Attached Figure Description

[0017] Figure 1 This is a diagram illustrating the general structure of an engine.

[0018] Figure 2 This is a perspective view illustrating an air intake duct installed on a cover.

[0019] Figure 3 This is an example along Figure 2 A cross-sectional view of the intake pipe of line AA.

[0020] Figure 4 This is an example along Figure 3 A cross-sectional diagram of the intake pipe of the BB line.

[0021] Figure 5 (A) is a cross-section of an air intake pipe with an insulating component installed in the space within the partition wall. Figure 5 (B) is a cross-section of an air intake pipe in which a heating unit is installed in the space within the partition wall.

[0022] Label Explanation

[0023] 10 Engine (internal combustion engine), 11 Internal combustion engine body, 5 Intake pipe (intake device), 20 Turbocharger, 50 Connection part, 53 Throttling orifice, 54 Spacer wall, 60 Space, 61 First flow path, 62 Second flow path, 70 Insulation component, 71 Heating unit, 120 Connector part, 522 End (one end), 522a Inner wall, E-curved surface Detailed Implementation

[0024] (General structure of the engine)

[0025] Figure 1 This is a diagram illustrating the general structure of engine 10. Engine 10 is a spark-ignition four-cylinder gasoline engine, an example of an internal combustion engine, but it is not limited to this. It can also be an engine other than four cylinders, such as a compression-ignition diesel engine or other types of engines.

[0026] The engine 10 includes an internal combustion engine body 11, a cover 12, a crankcase 13, pistons 14, a combustion chamber 15, an intake passage 16, a turbocharger 20, an intercooler 22, and a throttle valve 24. The internal combustion engine body 11 has cylinders 11a, a cover 12 disposed above the cylinders 11a, and a crankcase 13 disposed below the cylinders 11a. The pistons 14 reciprocate within the combustion chamber 15 of the cylinders 11a. Each cylinder of the internal combustion engine body 11 is connected to the intake passage 16 via an intake manifold 16a.

[0027] Air filter 17 is installed near the inlet portion of intake passage 16. Compressor 20a of turbocharger 20 is located downstream of air filter 17 in intake passage 16 and compresses the intake air. Compressor 20a is integrally connected to turbine 20b disposed in exhaust passage via a connecting shaft.

[0028] An intercooler 22 is located downstream of the compressor 20a in the intake passage 16 to cool the pressurized air. An electronically controlled throttle valve 24 is located downstream of the intercooler 22. An intake manifold 16a is located downstream of the throttle valve 24.

[0029] A leakage gas guiding passage 31 is provided inside the cylinder 11a and the cover 12. This leakage gas guiding passage 31 extends through the cylinder 11a and the cover 12, connecting the crankcase 13 to the main partition 43, and guiding the leakage gas present in the crankcase 13 towards the main partition 43. Furthermore, a connecting port 431 is provided in the main partition 43, connecting the cover 12 to the main partition 43, and guiding the leakage gas present in the internal space of the cover 12 towards the main partition 43.

[0030] The leaking gas is guided to the main separator 43 via the leaking gas guide passage 31. The leaking gas separated by the main separator 43 flows back to the intake manifold 16a via the leaking gas return passage 36 that connects the main separator 43 and the intake manifold 16a.

[0031] A PCV (Positive Crankcase Ventilation) valve 38 is provided at the end of the main partition 43 side of the leaked gas return passage 36. The PCV valve 38 is configured as a differential pressure valve that operates based on the differential pressure between the internal space of the cover 12 upstream and the intake manifold 16a downstream. The PCV valve 38 is used to adjust the flow rate of leaked gas returning to the intake manifold 16a and to prevent leaked gas from flowing back into the internal space of the cover 12.

[0032] A new gas inlet passage 34 is provided, connecting the internal space of the cover 12 to the intake passage 16 upstream of the compressor 20a and downstream of the air filter 17. More specifically, the new gas inlet passage 34 connects the intake passage 16 to an atmospheric separator 44. The atmospheric separator 44 is disposed within the cover 12 and includes a first connection port 441 and a second connection port 442. The first connection port 441 connects to the inside of the cover 12. The second connection port 442 connects to the new gas inlet passage 34. Furthermore, a new gas guide passage 33 connects the inside of the cover 12 to the inside of the crankcase 13. Therefore, new gas passing through the intake passage 16 is introduced into the internal space of the cover 12 and the crankcase 13 via the new gas inlet passage 34, the atmospheric separator 44, and the new gas guide passage 33.

[0033] When the engine 10 operates in naturally aspirated mode, the combustion chamber 15, downstream of the throttle valve 24, and the intake manifold 16a are under negative pressure, while the intake passage 16, upstream of the compressor 20a, is under atmospheric pressure. Therefore, fresh air flows through the fresh air inlet passage 34, the atmospheric side separator 44, the cover 12, the fresh air guide passage 33, and the crankcase 13. Additionally, blow-by gas returns from the crankcase 13 and the cover 12 to the intake manifold 16a via the main separator 43 and the blow-by gas return passage 36. In the main separator 43, oil components are separated from the blow-by gas. Thus, the blow-by gas is supplied from the intake manifold 16a to the combustion chamber 15, enabling combustion.

[0034] When the engine 10 is operating in a boosted state, the combustion chamber 15 downstream of the compressor 20a and the intake manifold 16a are under positive pressure, while the intake passage 16 upstream of the compressor 20a is under negative pressure. Therefore, leaking gas flows sequentially from the crankcase 13 through the leaking gas guide passage 31, the main separator 43, the cover 12, the atmospheric separator 44, and the fresh gas inlet passage 34, and flows counter-currently towards the intake passage 16 upstream of the compressor 20a. In the atmospheric separator 44, oil components are separated from the leaking gas. Thus, the leaking gas is supplied to the combustion chamber 15, enabling combustion.

[0035] In the above structure, the merging portion of the intake passage 16 between the turbocharger 20 and the air filter 17 and the fresh gas introduction passage 34 is achieved by the intake pipe 5. The intake pipe 5 is an example of the intake device of an internal combustion engine. The intake pipe 5 and the turbocharger 20 are connected to the internal combustion engine body 11. The intake pipe 5 will be described below.

[0036] (Structure of the air intake pipe)

[0037] Figure 2 This is a perspective view illustrating the air intake pipe 5 installed on the cover 12. Furthermore, in Figure 2The following figures show the mutually orthogonal X, Y, and Z directions.

[0038] The cover 12, for example, is made of resin, aluminum, or the like, and is disposed on the upper part of the cylinder 11a. The shapes of the cover 12 and the cylinder 11a are schematically represented by cuboid shapes. A connector portion 120, which connects to the air intake pipe 5, is provided near the corner of the cover 12. The connector portion 120 corresponds to the end of the new gas inlet passage 34 on the cover 12 side. Furthermore, the connector portion 120 is an example of a vent for leaking gas.

[0039] The intake duct 5 is made of steel, for example, and has a connecting portion 50, a first piping portion 51, and a second piping portion 52. The connecting portion 50 extends in a direction orthogonal to the extending directions of the first piping portion 51 and the second piping portion 52. The connecting portion 50 is connected to a portion of the side of the first piping portion 51 and one end of the second piping portion 52. The connecting portion 50 is inserted into the opening of the connector portion 120 of the cover 12. Thus, the fresh gas inlet passage 34 inside the cover 12 communicates with the flow path inside the intake duct 5. In addition, a sealing member such as an O-ring is provided inside the connector portion 120 between it and the connecting portion 50.

[0040] The upstream side of the first piping section 51 is connected to the air filter 17, and the downstream side of the first piping section 51 is connected to the compressor 20a of the turbocharger 20. The second piping section 52 is thinner than the first piping section 51 and is connected to the connecting section 50 and the first piping section 51. In the first piping section 51, intake air flows from the air filter 17 toward the compressor 20a. When the engine 10 is operating in a turbocharged state, through the connecting section 50 and the second piping section 52, leaking gas from the crankcase 13 flows toward the first piping section 51.

[0041] Thus, the intake pipe 5 connects the cover 12, the air filter 17, and the compressor 20a. If the connection 50 between the cover 12 and the intake pipe 5 is via a flexible hose, regulations require the installation of a pressure sensor or similar device to detect hose disconnection. However, in this example, a flexible hose is not used; instead, the connection 50 of the intake pipe 5 is directly inserted into the connector 120 of the cover 12. Therefore, a detection unit for disconnection, such as a pressure sensor, is not needed.

[0042] Figure 3 This is an example along Figure 2 A cross-sectional view of the intake pipe 5 of line AA. Figure 4 This is an example along Figure 3A cross-sectional view of the intake pipe 5 of the BB line. A first flow path 61 is provided inside the first piping section 51, and a second flow path 62 is provided inside the second piping section 52 and the connecting section 50. The second piping section 52 has an extension 521 extending parallel to the first piping section 51 and an end 522 bending from the extension 521 toward the first piping section 51. Furthermore, the end 522 is an example of one end of the second flow path 62. The cross-sectional area of ​​the first flow path 61 is larger than the cross-sectional area of ​​the second flow path 62. As an example, the cross-section of the first flow path 61 is approximately circular, and the cross-section of the second flow path 62 is approximately rectangular, but it is not limited to this, and other cross-sectional shapes may be used.

[0043] The opposite end of the extension 521 is connected to the connecting portion 50. The connecting portion 50 is bent at a right angle (Y direction) relative to the extension 521 and inserted into the connector portion 120. A throttling orifice 53 is provided in the connecting portion 50 to increase the pressure drop of leaking gas. The throttling orifice 53 is integrally formed with the connecting portion 50. When the engine 10 is operating in a natural intake state, the throttling orifice 53 functions to create a negative pressure inside the engine 10.

[0044] In this way, the throttle orifice 53 is not located in the connector portion 120 of the cover 12, but in the intake pipe 5. Therefore, by removing the intake pipe 5 from the cover 12, maintenance of the throttle orifice 53 is easy. Alternatively, unlike this example, the throttle orifice 53 may also be located inside the connector portion 120.

[0045] The first flow path 61 extends linearly along the X direction. Fresh gas from the air filter 17 flows within the first flow path 61 as indicated by reference numeral D1 and is introduced into the booster 20. The second flow path 62 bends approximately at a right angle between the connection 50 and the second piping section 52, extends linearly along the X direction within the second piping section 52, and bends obliquely relative to the first flow path 61 at its end 522. Leaking gas from the cover 12 flows as indicated by reference numeral D2 and merges with the fresh gas in the first flow path 61. Thus, the second flow path 62 extends adjacent to the first flow path 61, merging with the first flow path 61 at its end 522 obliquely rearward from the direction of the fresh gas flow in the first flow path 61. Furthermore, the cross-sectional area of ​​the first flow path 61 is substantially constant upstream and downstream of the merging point with the second flow path 62.

[0046] Furthermore, the first flow path 61 and the second flow path 62 are adjacent to each other in the Y direction. A space 60 extending in the X direction is provided inside the partition wall 54 that separates the extensions 521 of the first flow path 61 and the second flow path 62. Therefore, the first flow path 61 and the second flow path 62 are thermally cut off from each other by the space 60. Thus, compared to the absence of the space 60, the rapid cooling of the leaking gas in the extension 521 by the fresh gas in the first flow path 61 is suppressed, making it difficult for moisture in the leaking gas to crystallize. Therefore, the formation of ice crystals P in the second flow path 62 caused by the cooling of the fresh gas in the first flow path 61 is suppressed. Furthermore, the longer the length of the space 60 in the X direction, the more difficult it is for the leaking gas to be cooled, which is therefore preferable.

[0047] Furthermore, even if the moisture in the leaked gas crystallizes to form ice crystals P, since the second flow path 62 merges with the first flow path 61 at its end 522 in an inclined direction relative to the direction of the new gas flow, a large amount of ice crystals P entering the first flow path 61 can easily flow downstream with the new gas. In contrast, assuming that the leaked gas merges directly with the first flow path 61 from the connection 50 in a direction orthogonal to the direction of the new gas flow, a large amount of ice crystals P accumulate and grow on the wall surface 51a opposite the opening of the second flow path 62 in the first flow path 61, thereby easily forming large ice crystals Ps.

[0048] However, in this example, the second flow path 62 merges with the first flow path 61 in a direction inclined relative to the flow of the fresh gas within the first flow path 61. Therefore, even if small ice crystals P are generated along with the fresh gas, they easily flow towards the compressor 20a side along with the flow of the fresh gas within the first flow path 61. Thus, unlike the case described above, ice crystals P are less likely to accumulate on the wall 51a of the first flow path 61. Therefore, the formation of larger ice crystals Ps due to the growth of a large number of ice crystals P is suppressed, resulting in reduced damage to the compressor 20a.

[0049] The angle θ at which the second flow path 62 merges with the first flow path 61 is... Figure 3 The angle θ in the cross-section is defined as the angle between the tangent L of, for example, the reference point S of the inner wall 522a of the downstream end 522 of the second flow path 62, and the wall surface 51a within the first flow path 61. Here, the reference point S is, for example, the center position of the width of the second flow path 62 in the Y direction. If the angle θ is less than 90 degrees, the above-mentioned effect can be obtained, but the smaller the angle θ, the more difficult it is for ice crystals P to reach the wall surface 51a of the first flow path 61, and the more difficult it is to generate large ice crystals Ps, which is therefore preferred.

[0050] Furthermore, at end 522, the downstream end 54a of the partition wall 54 has a curved surface E that bulges towards the second flow path 62 and bends towards the first flow path 61. Therefore, compared to the case where the downstream end 54a is an angular wall that bends at a right angle towards the first flow path 61, the leaking gas can flow smoothly into the first flow path 61 along the curved surface E, reducing the resistance to the leaking gas. Moreover, according to the curved surface E, compared to the case where the downstream end 54a is an angular wall as described above, more leaking gas contacts the partition wall 54, thus suppressing the formation of ice crystals P using the space 60. In addition, the curved surface E can also be an arc shape (e.g., a fan-shaped arc shape with a central angle of 90 degrees).

[0051] Furthermore, the inner wall 522a of the end portion 522 of the second flow path 62 has a curved surface that bends from the extension 521 toward the first flow path 61. For example, the inner wall 522a of the second flow path 62 bends into an arc shape toward the first flow path 61 in an S-shape from the extension 521 and smoothly connects with the inner wall of the first flow path 61. Therefore, the resistance of leaking gas entering the first flow path 61 from the second flow path 62 is reduced.

[0052] In contrast, assuming the inner wall 522 is a flat surface that forms an obtuse angle with respect to the wall surface of the extension 521 and extends towards the first flow path 61, the leaking gas diffuses at the corner between the extension 521 and the end 522, thus experiencing greater resistance compared to a curved surface. Therefore, by having the inner wall 522a of the end 522 curved towards the first flow path 61, the resistance experienced by the leaking gas can be suppressed, reducing pressure loss.

[0053] Thus, by means of the intake pipe 5, the formation of ice crystals P from moisture in the leaked gas can be suppressed, thereby preventing damage to the turbocharger 2. Furthermore, the inner wall of the second flow path 62 can be hydrophobically treated to suppress the formation of ice crystals P. Examples of hydrophobic treatment include Teflon (registered trademark), but it is not limited to this. Additionally, as in the following examples, heat insulation components and heating units can also be installed within the space 60.

[0054] (Other embodiments)

[0055] Figure 5 (A) is a cross-sectional view illustrating an air inlet pipe 5 in a space 60 within a partition wall 54, where an insulating member 70 is provided. Figure 5 In (A), regarding and Figure 4 Common structures are labeled with the same number, and their descriptions are omitted.

[0056] Examples of materials that can be used as the insulation component 70 include PET (Polyethylene Terephthalate), polyurethane foam, and fiberglass, but these are not limited to these, and other materials may also be used. According to this example, the insulation component 70 more effectively cuts off heat between the first flow path 61 and the second flow path 62, and therefore, compared to the case without the insulation component 70, it can more effectively suppress the formation of ice crystals P within the second flow path 62.

[0057] Figure 5 (B) is a cross-sectional view illustrating an air intake pipe 5 for which a heating unit 71 is installed in the space 60 within the partition wall 54. Figure 5 In (B), regarding... Figure 4 Common structures are labeled with the same number, and their descriptions are omitted.

[0058] Heating unit 71 can be a heater, but is not limited to it. Heating unit 71 is disposed in contact with the inner wall 54a on the second flow path 62 side to heat the second flow path 62. According to this example, the second flow path 62 is heated by heating unit 71, therefore, the formation of ice crystals P in the second flow path 62 is suppressed more effectively compared with the case without heating unit 71.

[0059] Furthermore, in this example, intake pipe 5 is listed as the intake device for an internal combustion engine, but it is not limited to this. For example, the above-described structure may be provided instead of intake pipe 5 in the air filter hose extending from air filter 17.

[0060] The above embodiments are examples of preferred implementations of the present invention. However, they are not limited thereto, and various modifications can be made without departing from the spirit of the present invention.

Claims

1. An internal combustion engine, wherein, The internal combustion engine has the following features: Internal combustion engine body; A turbocharger, connected to the main body of the internal combustion engine; and The intake device is connected to the main body of the internal combustion engine. The air intake device has: The first flow path introduces fresh gas into the booster; and The second flow path is for the flow of leaked gas from the main body of the internal combustion engine. The second flow path extends adjacent to the first flow path, and the second flow path merges with the first flow path at one end from an oblique rearward direction of the direction of the new gas flow. A space is provided inside the partition wall that separates the first flow path and the second flow path that are adjacent to each other.

2. The internal combustion engine according to claim 1, wherein, The partition wall has a curved surface at one end, the curved surface bulging out toward the second flow path side and bending toward the first flow path side.

3. The internal combustion engine according to claim 1, wherein, The second flow path has a connecting portion, which is connected to the vent of the leaking gas, and the vent is located in the cover of the internal combustion engine. The connecting part has a throttling orifice.

4. The internal combustion engine according to claim 1, wherein, The internal combustion engine has a heat insulation component, which is disposed in the space.

5. The internal combustion engine according to claim 1, wherein, The internal combustion engine has a heating unit, which is disposed in the space and heats the second flow path.

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