Cover unit

Abstract

To provide a cover unit which covers a high temperature part related to a fluid system and can release an atmosphere around the high temperature part and prevent entry of foreign objects.SOLUTION: A cover unit 17 includes: a first cover 36 for covering a member 26 forming a fluid system 23a; and a second cover 38 which covers a valve body 16 connected to the fluid system 23a and forms an opening 40 between itself and the first cover 36. A portion 36b, which forms the opening 40 between the first cover 36 and the second cover 38, of the first cover 36 extends to an internal space S2 of a portion, which covers the valve body 16, of the second cover 38.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cover unit, and more particularly to a unit for covering a portion through which a high-temperature fluid may flow. [Background technology]

[0002] For example, an internal combustion engine such as a diesel engine is provided with an exhaust gas flow path that joins exhaust gases discharged from the exhaust valves of each cylinder and discharges them to the outside through an exhaust port. A turbocharger is provided upstream of the exhaust port in this exhaust gas flow path, and the turbocharger's turbine rotates in response to the flow of exhaust gas, thereby operating a compressor that is coaxially connected to the turbine and is located in the air intake flow path from the fresh air intake to the intake valve. This compresses the air taken in and supplies it to the combustion chamber (see, for example, Patent Document 1).

[0003] Furthermore, this type of flow path is generally provided with a safety valve for releasing high-pressure exhaust gas when the exhaust gas pressure rises abnormally for some reason. That is, when the exhaust gas is in a normal flow state, the exhaust gas release port provided in the flow path is blocked by the valve body of the safety valve, which is biased by a spring or the like. However, when the exhaust gas pressure rises above a predetermined level, the force with which the high-pressure exhaust gas presses the valve body exceeds the biasing force of the spring, causing a gap to form between the valve body and the release port, and the high-pressure exhaust gas is discharged outside the flow path (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-234733 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-126323 Summary of the Invention [Problem to be solved by the invention]

[0005] In this type of internal combustion engine, for safety reasons, covers are typically provided on high-temperature components, such as the exhaust pipe forming the exhaust gas flow path and the safety valve attached to the exhaust pipe. However, completely covering these high-temperature components with covers could result in problems, such as the high temperature surrounding the safety valve, which could overheat the safety valve itself. To solve this problem, for example, a gap could be provided between the exhaust pipe cover and the safety valve cover, allowing gas around the safety valve to escape to the outside. However, if an opening were provided on the outer periphery of the safety valve cover, there would be a risk that foreign matter, such as oil, adhering to the exhaust pipe cover for some reason could creep along the surface of the exhaust pipe cover and enter the inside of the cover through the gap between the exhaust pipe cover and the safety valve cover. Because foreign matter, such as oil, adhering to the high-temperature components could ignite, it is important to reliably prevent such foreign matter from entering the high-temperature components, from a safety perspective.

[0006] The above-mentioned problem is not limited to the exhaust pipes and safety valves of internal combustion engines, but can occur in any fluid system in which a cover is provided through which a high-temperature fluid can flow.

[0007] In view of the above circumstances, the technical problem to be solved in this specification is to provide a cover unit that can cover high-temperature parts related to a fluid system, open the atmosphere surrounding the high-temperature parts, and prevent the intrusion of foreign matter. [Means for solving the problem]

[0008] The above-mentioned object is achieved by a cover unit according to the present invention, which is characterized in that it comprises a first cover that covers a member that forms a fluid system, and a second cover that covers a valve body connected to the fluid system and forms an opening between itself and the first cover, and a portion of the first cover that forms the opening between itself and the second cover extends into an internal space of a portion of the second cover that covers the valve body.

[0009] In this manner, the cover unit according to the present invention provides an opening between the first cover, which covers the components forming the fluid system, and the second cover, which covers the valve body connected to the fluid system. This allows the atmosphere around the valve body to be released to the outside space through the opening, while protecting the parts that can become hot with each cover. This makes it possible to prevent the components forming the fluid system or the valve body from becoming too hot. Furthermore, by configuring the portion of the first cover that forms the opening with the second cover to extend into the inner space of the portion of the second cover that covers the valve body, the tip of the first cover extending toward the valve body can be covered by the second cover. This prevents foreign matter, such as oil, from entering the inner space of the second cover from the end of the first cover. Therefore, while avoiding the valve body being exposed to high-temperature fluid, it is possible to prevent the intrusion of foreign matter into the valve body and prevent malfunctions caused by the adhesion of foreign matter (e.g., fire caused by oil adhering to the high-temperature portion of the valve body).

[0010] In addition, in the cover unit according to the present invention, a folded portion that is folded back toward the outside of the second cover may be provided at the tip of the extension portion of the first cover that extends into the inner space.

[0011] By providing a folded portion at the tip of the extension portion in this manner, for example, when the extension portion extends horizontally, it is possible to reliably prevent foreign matter such as oil from dripping from the tip of the extension portion and penetrating further inward, thereby making it possible to more effectively prevent problems caused by the penetration of foreign matter.

[0012] In the cover unit according to the present invention, the second cover may cover both the extending portion of the first cover that extends into the inner space and the folded-back portion.

[0013] By covering not only the folded portion of the first cover but also the extended portion in this way, the second cover, which is positioned further outward than the first cover, can protect a larger portion of the first cover, thereby more effectively preventing foreign matter from entering the interior space of the second cover via the first cover.

[0014] In the cover unit according to the present invention, the fluid system may have an exhaust pipe connected to a combustion chamber of an internal combustion engine, and the valve body may be configured to release the fluid into an external space of the fluid system when the fluid in the fluid system has a pressure equal to or higher than a predetermined pressure. In this case, the first cover may cover the exhaust pipe, and the second cover may cover the valve body connected to the exhaust pipe.

[0015] The exhaust gas flowing through the exhaust pipe is generated during combustion and therefore can become extremely hot and dangerous. By providing the cover unit according to the present invention, it is possible to prevent the high-temperature exhaust gas from remaining around the valve body and exposing the valve body to high temperatures, while also reliably preventing problems caused by foreign matter such as oil entering the inner space of the second cover and adhering to the safety valve. [Effects of the Invention]

[0016] As described above, the cover unit according to the present invention can cover high-temperature parts related to the fluid system, while allowing the atmosphere surrounding the high-temperature parts to be open, and can improve the safety of the surrounding area by preventing the intrusion of foreign matter. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a conceptual diagram of an internal combustion engine equipped with a cover unit according to a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view taken along the line AA of the cover unit shown in FIG. 1. [Figure 3] 3 is a cross-sectional view of the first cover shown in FIG. 2 taken along line BB. [Figure 4] 8 is a cross-sectional view taken along the line AA of a cover unit according to a second embodiment of the present invention. FIG. [Figure 5] 10 is a cross-sectional view taken along the line AA of a cover unit according to a third embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] The following describes the details of a cover unit according to one embodiment of the present invention with reference to the drawings. In this embodiment, the cover unit is attached to an internal combustion engine so as to cover an exhaust pipe and a safety valve connected to the exhaust pipe.

[0019] Fig. 1 is a conceptual diagram of an internal combustion engine 10 according to one embodiment of the present invention, particularly illustrating a portion related to intake and exhaust. As shown in Fig. 1, the internal combustion engine 10 is a diesel engine used, for example, to supply torque to a generator motor of a ship or to rotate a propeller shaft of the ship, and includes a plurality of cylinders 11 arranged in series, a combustion chamber 12 for each cylinder 11, an intake gas passage 13 for supplying intake gas Ga to the combustion chamber 12, an exhaust gas passage 14 for discharging exhaust gas Gb from the combustion chamber 12, a turbocharger 15, a safety valve device 16, and a cover unit 17. Here, the exhaust gas passage 14 corresponds to a fluid system according to the present invention, and the safety valve device 16 corresponds to a valve body according to the present invention.

[0020] The intake gas passage 13 is mainly for compressing gas (usually air) taken in through the intake port 18 and sending it to the combustion chamber 12 of each cylinder 11. It has a main intake passage 19 with the intake port 18 at its upstream end, and an auxiliary intake passage 20 branching off from the main intake passage 19 and connected to the combustion chamber 12 of each cylinder 11. A compressor 21 of the turbocharger 15 is disposed in the main intake passage 19 downstream of the intake port 18. An intercooler (not shown) is also disposed in the main intake passage 19 downstream of the compressor 21. With this configuration, outside air taken in through the intake port 18 is compressed by the compressor 21 and supplied to the combustion chamber 12 through the main intake passage 19 and the auxiliary intake passage 20. The high-temperature air is cooled by the intercooler (not shown) disposed downstream of the compressor 21, and the cooled compressed air is supplied to the combustion chamber 12.

[0021] The exhaust gas flow path 14 is for discharging the exhaust gas Gb generated in the combustion chamber 12 from the internal combustion engine 10, and has a main exhaust path 23 with an exhaust port 22 provided at its downstream end, and a secondary exhaust path 24 that merges with the main exhaust path 23 to connect the combustion chamber 12 and the main exhaust path 23. In this embodiment, two main exhaust paths 23 (a first main exhaust path 23a and a second main exhaust path 23b) are provided, and three secondary exhaust paths 24 (24a, 24b) are connected to each of the main exhaust paths 23a, 23b. The main exhaust paths 23a, 23b merge and lead to a turbine 25 of the turbocharger 15, and an exhaust port 22 is provided downstream of the merged path. With this configuration, exhaust gas Gb discharged from combustion chamber 12 reaches main exhaust passages 23a, 23b through sub-exhaust passages 24a, 24b, and passes through turbine 25 disposed downstream of main exhaust passages 23a, 23b, driving turbine 25, and is discharged from exhaust port 22. Driving turbine 25 also drives compressor 21 connected to turbine 25, and air taken into main intake passage 19 from intake port 18 is compressed and supplied to combustion chamber 12.

[0022] In this case, the main exhaust passages 23 (23a, 23b) of the exhaust gas flow passage 14 are arranged in the longitudinal direction of the internal combustion engine 10, i.e., in a direction along the parallel arrangement of the multiple cylinders 11 (left and right direction in FIG. 1). Therefore, the main exhaust pipes 26a, 26b (see FIG. 2) forming each of the main exhaust passages 23a, 23b are also arranged in a direction along the longitudinal direction of the internal combustion engine 10. In this embodiment, the two main exhaust passages 23a, 23b (main exhaust pipes 26a, 26b) are arranged side by side one above the other. That is, in this embodiment, the up and down direction in FIG. 2 is defined as the vertical direction.

[0023] At least one of the two main exhaust passages 23a, 23b (the lower main exhaust passage 23a in FIG. 2) has a branch passage 27a branching off from the main exhaust passage 23a. In this case, the main exhaust pipe 26a corresponding to one of the main exhaust passages 23a has a branch pipe 27b at a position and in a shape corresponding to the branch passage 27a. The safety valve device 16 is connected to this branch pipe 27b (see FIG. 2).

[0024] The safety valve device 16 has a valve 28 that moves in response to pressure received by an end surface 28a, and in this embodiment, the device includes the valve 28, a biasing member 29 that biases the valve 28 against the pressure, a first base 30 and a second base 31 that hold the valve 28 and the biasing member 29, a seal portion 32 that can come into contact with the valve 28 when the valve 28 is in a closed state, and a thin plate laminate 33. Here, the biasing member 29 can be formed of an elastic member such as a compression spring. Furthermore, the seal portion 32 can be formed of graphite from the viewpoint of pressure resistance, etc.

[0025] In this embodiment, the biasing member 29 biases a connecting body 34 that is connected and fixed to the valve 28. The valve 28 is biased in a predetermined direction by the biasing member 29 via the connecting body 34, so that it can come into close contact with the seal portion 32. The first base 30 to which the seal portion 32 is attached is provided with a communication hole 30a that communicates with the adjacent exhaust gas flow path 14, and through this communication hole 30a, an end face 28a of the valve 28 faces the main exhaust path 23a (branch path 27a), which serves as a flow space for the exhaust gas Gb.

[0026] The safety valve device 16 configured as described above is configured to switch between an open and closed state depending on the pressure of the gas in the main exhaust path 23a (branch path 27a). Specifically, when the pressure in the branch path 27a (i.e., the pressure of the exhaust gas Gb) is below a predetermined pressure, the valve 28 remains in close contact with the seal portion 32, blocking the communication between the main exhaust path 23a and the external space S. When the pressure in the branch path 27a is equal to or higher than the predetermined pressure, a gap is generated between the valve 28 and the seal portion 32, thereby establishing communication between the main exhaust path 23a and the external space S through the gap and further through the thin plate stack 33. The communication structure with the external space S will be described later.

[0027] The safety valve device 16 having the above configuration is fixed to the branch pipe 27b by fastening the first base 30 and the second base 31 to a flange 27b1 provided on the outer periphery of the end of the branch pipe 27b with a plurality of bolts 35 (see FIG. 2). Of course, the means for fixing the safety valve device 16 to the branch pipe 27b is not limited to this, and any fixing means can be used.

[0028] In the present embodiment, one safety valve device 16 having the above configuration is connected to each of the main exhaust passages 23a, 23b. Although FIG. 1 shows that the safety valve device 16 is connected to an intermediate region of one main exhaust passage 23a and the safety valve device 16 is connected to the upstream end of the other main exhaust passage 23b, the connection position of the safety valve device 16 is not particularly limited. In the configuration shown in FIG. 1, the safety valve device 16 can be connected to any position as long as it is not near the turbocharger 15. The orientation of the safety valve device 16 can also be set arbitrarily without any particular limitations. That is, in the present embodiment, the safety valve device 16 is connected to the main exhaust pipe 26a (branch pipe 27b) so that the movable direction of the valve 28 is horizontal as shown in FIG. 2, but the safety valve device 16 may be connected to the upper or lower side of the main exhaust pipe 26a.

[0029] Each of the main exhaust pipes 26a, 26b is covered over its entire longitudinal length by a first cover 36 (see FIG. 1). When the two main exhaust pipes 26a, 26b are arranged vertically side by side as in this embodiment, the first cover 36 vertically straddles the two main exhaust pipes 26a, 26b and covers the entire exposed portion of each of the main exhaust pipes 26a, 26b to the external space S (mainly the upper and outer portions) (see FIG. 2). In this case, the first cover 36 is fixed to the internal combustion engine body 37.

[0030] Furthermore, in the case where a branch passage 27a is provided in one main exhaust passage 23a and the safety valve device 16 is connected to a branch pipe 27b that forms this branch passage 27a as in the present embodiment, a hole 36a is provided in the first cover 36 at a portion where the branch pipe 27b is disposed. The safety valve device 16 is connected to the branch pipe 27b through this hole 36a so that most of the safety valve device 16 is located outside the first cover 36. In this case, for example, by fitting the first base 30 of the safety valve device 16 into the hole 36a, the space S1 between the first cover 36 and the main exhaust pipes 26a, 26b and the space between the safety valve device 16 and a second cover 38 (described later, i.e., the inner space S2 of the second cover 38) are blocked off.

[0031] The safety valve device 16 is covered with a second cover 38. In this embodiment, the second cover 38 is cylindrical and covers the ceiling side and outer periphery side of the generally cylindrical safety valve device 16. This second cover 38 is fixed to the safety valve device 16, for example. In the example shown in Fig. 2, a ceiling portion 38a of the second cover 38 and the first base 30 and second base 31 of the safety valve device 16 are fastened and fixed to each other by multiple sets of bolts 39a, 39b.

[0032] Additionally, an extension portion 36b is provided on the first cover 36 radially outward of the hole 36a, extending along the opening direction of the hole 36a and toward the safety valve device 16. The extension portion 36b is, for example, cylindrical and extends to the inner space S2 of the cylindrical portion 38b of the second cover 38. In this case, an annular opening 40 is formed between the extension portion 36b of the first cover 36 and the cylindrical portion 38b of the second cover 38 (see FIG. 2 for both). The tip of the cylindrical portion 38b of the second cover 38 is spaced from the side cover portion 36c of the first cover 36, which covers the sides of the main exhaust pipes 26a, 26b and in which the hole 36a is provided. With the above configuration, the inner space S2 of the second cover 38 located outside the safety valve device 16 is connected to the external space S of the internal combustion engine 10 via the opening 40. Therefore, when the valve 28 of the safety valve device 16 moves away from the seal portion 32, the exhaust gas Gb in the branch passage 27a connected to the main exhaust passage 23a can be released into the external space S through the gap between the valve 28 and the seal portion 32, the thin plate laminate 33, the inner space S2 of the second cover 38, and the opening 40.

[0033] The smaller the radial distance between the extending portion 36b and the cylindrical portion 38b, the greater the effect of preventing foreign matter from entering from the outside (sealing performance), but if the distance is too small, there is a risk that the smooth release of gas (exhaust gas Gb) from the inner space S2 to the outer space S will be hindered. Therefore, it is preferable to set the radial distance between the extending portion 36b and the cylindrical portion 38b (the width dimension of the opening 40) from the above-mentioned viewpoint.

[0034] The first cover 36 and the second cover 38 described above constitute the cover unit 17 according to the present invention.

[0035] As described above, in the cover unit 17 according to the present embodiment or the internal combustion engine 10 equipped with this cover unit 17, the opening 40 is provided between the first cover 36 that covers the main exhaust pipes 26a, 26b that form the main exhaust passages 23a, 23b, and the second cover 38 that covers the safety valve device 16 as a valve body connected to the branch pipe 27b that branches off from the main exhaust pipe 26a. Therefore, while the covers 36, 38 protect parts that may become hot, the exhaust gas Gb that is released into the atmosphere around the safety valve device 16, i.e., the inner space S2 of the second cover 38, can be released to the external space S via the opening 40. This makes it possible to prevent the high-temperature exhaust gas Gb from remaining around the safety valve device 16, thereby preventing the safety valve device 16 from becoming hot. Furthermore, by configuring a portion of the first cover 36 that forms the opening 40 between itself and the second cover 38 to extend into the inner space S2 of the portion of the second cover 38 that covers the safety valve device 16, the tip of the portion of the first cover 36 that extends toward the safety valve device 16 (extension portion 36b) can be covered by the second cover 38. This makes it possible to prevent foreign matter F (see FIG. 3 ) such as oil from entering the inner space S2 of the second cover 38 through the opening 40 between the first cover 36 and the second cover 38. Therefore, it is possible to prevent the safety valve device 16 from being exposed to high-temperature exhaust gas Gb while preventing the foreign matter F from entering the safety valve device 16, and to prevent malfunctions due to adhesion of the foreign matter F (for example, fire caused by oil adhering to a high-temperature portion of the safety valve device 16) from occurring.

[0036] In this embodiment, the extension portion 36b of the first cover 36 is cylindrical (see FIG. 3). According to the above configuration, when the safety valve device 16 is connected laterally (horizontally) to the main exhaust pipe 26a as shown in FIGS. 2 and 3, for example, foreign matter F, such as oil, that has adhered to the outer surface of the extension portion 36b by running down the surface of the first cover 36 or by directly dropping will move circumferentially along the surface of the extension portion 36b due to its own weight and drop downward. Therefore, it is possible to more effectively prevent the foreign matter F from entering the inner space S2 of the second cover 38.

[0037] Furthermore, as in this embodiment, by forming the annular opening 40 between the first cover 36 and the second cover 38, it is possible to generate a convection current of outside air (the atmosphere of the external space S) that enters from the lower portion 40a of the annular opening 40, passes through the internal space S2, and is discharged from the upper portion 40b of the opening 40. Therefore, it is possible to smoothly discharge the exhaust gas Gb discharged into the internal space S2 into the external space S.

[0038] Although the first embodiment of the present invention has been described above, the cover unit according to the present invention can also have configurations other than those described above without departing from the spirit of the invention.

[0039] 4 shows an enlarged cross-sectional view of a main portion of a cover unit 41 according to a second embodiment of the present invention. The cover unit 41 according to this embodiment differs from the cover unit 17 according to the first embodiment in that the first cover 36 has a folded portion 36d at the tip of the extending portion 36b, which is folded back toward the outside of the second cover 38.

[0040] By providing the folded portion 36d at the tip of the extending portion 36b in this way, when the extending portion 36b extends horizontally, it is possible to reliably prevent a situation in which foreign matter such as oil drips from the tip of the extending portion 36b and adheres to the safety valve device 16. Therefore, it is possible to more highly likely prevent malfunctions caused by the intrusion of foreign matter.

[0041] 5 shows an enlarged cross-sectional view of a main portion of a cover unit 42 according to a third embodiment of the present invention. The cover unit 42 according to this embodiment differs from the cover units 17 and 41 according to the first and second embodiments in that the extension portion 36b of the first cover 36 has a shape that increases in diameter toward the tip side.

[0042] By making the extension portion 36b have an expanded diameter, it is possible to prevent foreign matter such as oil from moving toward the tip end on the extension portion 36b (particularly the upper portion of the extension portion 36b). Therefore, this configuration also makes it possible to highly likely prevent foreign matter from dripping from the tip end of the extension portion 36b and adhering to the safety valve device 16.

[0043] In the above explanation, the exhaust pipes (main exhaust pipes 26a, 26b and branch pipe 27b) are exemplified as objects to be covered by the first cover 36 of the cover units 17, 41, 42, but the application of the present invention is not limited to this. As long as it covers components that form a fluid system through which a high-temperature fluid flows, or more specifically, when it is necessary to cover components that form a fluid system in accordance with some law, regulation, or standard, the cover unit according to the present invention can be applied to components that form a fluid system of any configuration.

[0044] In the above description, the safety valve device 16 is exemplified as an object to be covered by the second cover 38 of the cover units 17, 41, 42, but the application of the present invention is not limited to this. The cover unit according to the present invention can be applied to a valve body of any configuration as long as it can control the flow of fluid in the above-mentioned fluid system in some form that involves release. [Explanation of symbols]

[0045] 10 Internal combustion engine 11 cylinders 12 Combustion chamber 13 Intake gas flow path 14 Exhaust gas flow path 15. Turbocharger 16 Safety valve device 17,41,42 Cover unit 18 Air intake 19 Main intake duct 20 Auxiliary intake passage 21 Compressor 22 Exhaust port 23, 23a, 23b Main exhaust passage 24, 24a, 24b Secondary exhaust passage 25 Turbine 26a, 26b Main exhaust pipe 27a Fork 27b Branch pipe 27b1 Tsubabe 28 valves 28a End face 29. Biasing member 30 First base 30a communication hole 31 Second base 32 Seal part 33 Thin plate laminate 34 Connector 35, 39a, 39b bolts 36 First Cover 36a Hole 36b Extension 36c Side cover part 36d Folded part 37 Internal combustion engine body 38 Second cover 38a Ceiling 38b Cylindrical part 40 Opening 40a lower part 40b Upper part Ga Intake gas Gb exhaust gas S External space of the internal combustion engine S1 Space between the first cover and the main exhaust pipe S2 Second cover inner space

Claims

1. a first cover that covers a member that forms a fluid system; a second cover that covers a valve body connected to the fluid system and forms an opening between the first cover and the second cover, A cover unit, wherein a portion of the first cover that forms the opening between itself and the second cover extends to an inner space of a portion of the second cover that covers the valve body.

2. The cover unit according to claim 1 , wherein a folded portion that is folded back toward the outside of the second cover is provided at a tip of the extension portion of the first cover that extends into the inner space.

3. The cover unit according to claim 1 or 2, wherein the second cover covers both the extension portion of the first cover that extends into the inner space and the folded-back portion.

4. the fluid system has an exhaust pipe connected to a combustion chamber of an internal combustion engine, and the valve body is configured to be able to release the fluid into an external space of the fluid system when the fluid in the fluid system is at or above a predetermined pressure, The cover unit according to claim 1 or 2, wherein the first cover covers the exhaust pipe, and the second cover covers the valve body connected to the exhaust pipe.

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