JP7042650B2 - Turbocharger - Google Patents

Description

The present disclosure relates to a turbocharger configured to supercharge an air-fuel mixture containing EGR gas.

Some turbochargers have air vents formed in the casing (Patent Document 1). Patent Document 1 describes the balance of the thrust acting on the impeller in a turbocharger in which a part of the high-pressure air supercharged by the impeller (compressor) flows into the space surrounded by the back surface of the impeller and the casing. It is disclosed that the high-pressure gas that has flowed into the above-mentioned space is released into the atmosphere from the air vents formed in the casing.

In addition, some engines equipped with a turbocharger use an exhaust gas recirculation (EGR) method in which a part of the exhaust gas after combustion is taken in again by the engine in order to reduce NOx (nitrogen oxide) (patented gas recirculation). Document 2). As disclosed in Patent Document 2, the EGR includes a high-pressure EGR that recirculates the exhaust gas on the upstream side of the turbine to the downstream side of the compressor, and the EGR that recirculates the exhaust gas on the downstream side of the turbine to the upstream side of the compressor. There is a low pressure EGR to make it.

Japanese Unexamined Patent Publication No. 8-254128 JP-A-2015-165124

If a turbocharger having an air vent in the casing described above is provided in an engine using the EGR method, the exhaust gas (EGR gas) recirculated upstream of the compressor will be discharged into the atmosphere from the air vent. Since EGR gas contains air pollutants such as NOx (nitrogen oxides), it may cause environmental deterioration outside the turbocharger.

Further, when the above-mentioned air vent is closed so that the EGR gas is not released into the atmosphere, the pressure between the compressed gas flowing into the back surface of the compressor and the gas flowing in the front side of the compressor. Since the compressor is pressed toward the front side due to the difference, there is a possibility that the load (thrust load) during operation on the bearing supporting the rotor of the compressor will increase. An increase in the load on the bearing during operation may lead to damage to the bearing and a decrease in the efficiency of the turbocharger.

In view of the above circumstances, an object of at least one embodiment of the present invention is to reduce the load on the bearing supporting the rotor during operation without significantly changing the existing equipment, and to use EGR gas. It is an object of the present invention to provide a turbocharger capable of preventing the external environmental deterioration of the turbocharger due to the inclusion air-fuel mixture.

(1) The turbocharger according to at least one embodiment of the present invention is
A turbocharger configured to supercharge an air-fuel mixture containing EGR gas.
A compressor housing that houses the compressor that compresses the air-fuel mixture, and
A turbine housing that houses a turbine connected to the compressor via a rotor, and
A bearing housing that houses a bearing that rotatably supports the rotor,
A first opening formed on the outer peripheral surface of the compressor housing or the bearing housing, which communicates with the first space formed on the back surface side of the compressor, and
A second opening formed on the outer peripheral surface of the turbine housing and communicating with a second space formed on the downstream side of the turbine of the turbine housing.
It comprises at least one air-fuel mixture exhaust flow path, which connects to.

According to the configuration (1) above, during operation of the turbocharger, the air-fuel mixture compressed by the compressor and increased in pressure flows into the first space formed on the back side of the compressor, whereas the turbine flows. Exhaust gas that has become low pressure by working on the turbine flows in the second space formed on the downstream side of the turbine of the housing. Therefore, due to the pressure difference between the air-fuel mixture in the first space and the exhaust gas in the second space, the air-fuel mixture in the first space is communicated to the first opening and the second space which are communicated with the first space. It flows into the second space through at least one air-fuel mixture exhaust flow path connecting the two openings. Since the air-fuel mixture exhaust flow path allows the air-fuel mixture to escape in the first space, it is possible to reduce the load on the thrust bearing among the bearings supporting the rotor during operation.

Further, the air-fuel mixture containing the EGR gas that has flowed into the second space is discharged from the gas discharge port of the turbine housing together with the exhaust gas flowing downstream of the turbine, and is provided on the downstream side of the gas discharge port in the flow direction of the exhaust gas. It is treated in the same way as the exhaust gas by the exhaust gas treatment device for treating the exhaust gas. Therefore, it is possible to prevent deterioration of the environment outside the turbocharger due to the air-fuel mixture discharged from the first space.

Further, in the turbocharger according to the above configuration, it is not necessary to newly install a blower device such as a pump or a processing device for processing the air-fuel mixture, and the first opening and the second opening are formed, and the first opening and the first opening and the processing device are formed. Since it is sufficient to provide at least one air-fuel mixture exhaust flow path connected to the second opening, the existing equipment is not significantly changed. In addition, there is no need to change existing equipment or piping other than the turbocharger. Therefore, the turbocharger described above can be easily changed from the existing equipment, and the existing equipment can be effectively utilized. In particular, when the first opening and the second opening are already formed, it is easier to change from the existing equipment.

(2) In some embodiments, in the configuration of (1) above,
A plurality of drain holes are formed on the outer peripheral surface of the turbine housing at intervals in the circumferential direction.
The second opening comprises at least one of the plurality of drain holes.

Generally, the turbine housing is configured so that the mounting angle can be changed according to the position and orientation of the chimney that discharges the exhaust gas to the outside. A plurality of drain holes are formed on the outer peripheral surface of the turbine housing at intervals in the circumferential direction so that drain can be appropriately discharged from the inside of the turbine housing even if the mounting angle of the turbine housing is changed. According to the configuration of (2) above, since the second opening is composed of at least one of a plurality of drain holes, an existing turbine housing provided with a plurality of drain holes can be utilized. Further, it is possible to standardize the parts between at least a part of the parts constituting the air-fuel mixture exhaust flow path and the connecting parts connected to the drain hole for draining the drain.

(3) In some embodiments, in the configuration of (2) above,
The plurality of drain holes include a lowermost drain hole located at the lowermost position in the vertical direction and an upper drain hole which is a drain hole other than the lowermost drain hole.
The second opening comprises at least one of the upper drain holes.

According to the configuration of (3) above, by making the second opening a drain hole other than the lowermost drain hole located at the lowermost position in the vertical direction, the drain passes through the second opening to the air-fuel mixture exhaust flow path. It is possible to suppress invasion.

(4) In some embodiments, in the configuration of (2) above,
The plurality of drain holes include a drain hole on the discharge port side located closest to the gas discharge port of the turbine housing.
The second opening comprises the drain hole on the discharge port side.

According to the configuration of (4) above, by making the second opening a drain hole on the discharge port side located closest to the gas discharge port of the turbine housing, it is possible to make another drain hole a second opening. Also, the second opening can be located away from the turbine. Therefore, it is possible to prevent the influence of the turbulence of the flow of the exhaust gas flowing through the second space, which is caused by the air-fuel mixture flowing from the second opening into the second space, from propagating to the turbine.

(5) In some embodiments, in the configurations (1) to (4) above,
A check valve provided in the middle of the air-fuel mixture exhaust flow path, further comprising a check valve for preventing exhaust gas from flowing from the second space toward the first space.

According to the configuration of (5) above, even if the pressure of the exhaust gas in the second space becomes higher than the pressure of the air-fuel mixture in the first space, the exhaust gas is discharged from the second space toward the first space by the check valve. Can be prevented from flowing. Here, the exhaust gas flowing inside the turbine housing contains a corrosive component such as sulfur oxide (SOx). Therefore, the turbocharger provided with the check valve described above can prevent the member facing the first space such as the compressor from being corroded or damaged by the corrosive component contained in the exhaust gas.

According to at least one embodiment of the present invention, it is possible to reduce the load during operation of the bearing supporting the rotor without significantly changing the existing equipment, and the turbocharger using the mixture containing EGR gas can be used. A turbocharger that can prevent deterioration of the external environment is provided.

It is a schematic block diagram which shows schematic structure of the diesel engine for a marine equipped with the turbocharger which concerns on one Embodiment of this invention. It is the schematic sectional drawing which shows schematic the turbocharger which concerns on one Embodiment of this invention. It is a figure for demonstrating the 1st opening, the 2nd opening and the air-fuel mixture exhaust flow path in one Embodiment of this invention, and is the schematic block diagram which shows the structure of the turbocharger schematically. It is a figure for demonstrating the air-fuel mixture exhaust flow path in one Embodiment of this invention, and is the schematic external view which shows the appearance of a turbocharger schematically. It is a figure corresponding to the arrow view of the line BB in FIG. 4, and is a schematic cross-sectional view of a turbine housing in which a gas discharge port is opened vertically upward. It is a figure corresponding to the arrow view of the line BB in FIG. 4, and is a schematic cross-sectional view of a turbine housing in which a gas discharge port opens diagonally upward.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. do not have.
For example, expressions that represent relative or absolute arrangements such as "in one direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a tolerance or a state of relative displacement at an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
For example, the expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also an uneven portion or a chamfer within the range where the same effect can be obtained. It shall also represent the shape including the part and the like.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions excluding the existence of other components.
The same reference numerals may be given to similar configurations, and the description thereof may be omitted.

FIG. 1 is a schematic configuration diagram schematically showing the configuration of a marine diesel engine including a turbocharger according to an embodiment of the present invention. As shown in FIG. 1, the turbocharger 3 recirculates a part of a diesel engine (hereinafter referred to as an engine 10) and an exhaust gas E (exhaust gas) discharged from the engine 10 to the upstream side of a compressor 7, which will be described later. It is provided in a marine diesel engine 1 (marine internal combustion engine) including an EGR system 11 and an exhaust gas treatment device 12 for removing harmful substances from the exhaust gas E discharged from the engine 10. In the embodiment shown in FIG. 1, the engine 10 is a main engine (marine main engine) for driving a propulsion device (not shown) for propelling a ship on which a diesel engine 1 is mounted.

As shown in FIG. 1, the turbocharger 3 includes a compressor 7 provided in the intake flow path 13 of the engine 10 and a turbine 8 provided in the exhaust flow path 14 of the engine 10. The compressor 7 and the turbine 8 are mechanically connected to each other via the rotor 9, and are configured to be integrally rotatable. The turbine 8 is rotated by the exhaust gas E discharged from the engine 10, and the combustion gas A (fresh air I or a mixture described later) supplied to the engine 10 is compressed by the compressor 7 that rotates in conjunction with the turbine 8. (Supercharged).

In the embodiment shown in FIG. 1, an air cleaner 15 for removing dust, dust, etc. from the combustion gas A is provided on the upstream side of the compressor 7 of the intake air flow path 13. Further, in the embodiment shown in FIG. 1, an air cooler 16 for cooling the combustion gas A compressed by the compressor 7 and having a temperature rise is provided on the downstream side of the compressor 7 of the intake flow path 13.

As shown in FIG. 1, the exhaust gas treatment device 12 described above is provided on the downstream side of the turbine 8 of the exhaust flow path 14. In some embodiments, the exhaust gas treatment apparatus 12 is a scrubber that removes harmful substances such as particulate matter (PM) and SOx (sulfur oxide) in the exhaust gas by injecting a cleaning liquid into the exhaust gas. Further, the exhaust flow path 14 is branched on the upstream side of the exhaust gas treatment device 12, and a part of the exhaust gas discharged from the engine 10 is discharged to the atmosphere from a chimney (not shown).

As shown in FIG. 1, the EGR system 11 is connected to the downstream side of the exhaust gas treatment device 12 of the exhaust flow path 14, upstream of the compressor 7 of the intake flow path 13, and downstream of the air cleaner 15. It has an EGR flow path 17 connected to the EGR flow path 17. A part of the exhaust gas discharged from the engine 10 by the EGR system 11 is returned to the intake flow path 13 on the inlet side of the compressor 7 via the EGR flow path 17. In the embodiment shown in FIG. 1, the EGR cooler 18 and the EGR valve 19 are provided in the EGR flow path 17. In another embodiment, an EGR blower is provided instead of the EGR cooler 18 to compensate for the pressure loss of the exhaust gas flowing through the EGR flow path 17.

FIG. 2 is a schematic cross-sectional view schematically showing a turbocharger according to an embodiment of the present invention. As shown in FIG. 2, the turbocharger 3 includes a rotor 9 (rotating shaft) extending along the axial direction (left-right direction in FIG. 2) and the above-mentioned compressor 7 provided at one end of the rotor 9 in the axial direction. The above-mentioned turbine 8 (turbine moving blade) provided at the other end of the rotor 9 in the axial direction, a bearing 30 that rotatably supports the rotor 9, and a thrust bearing 37 that supports the rotor 9 in the thrust direction are provided. I have.

As shown in FIG. 2, the turbocharger 3 further includes a compressor housing 4 for accommodating a compressor 7, a turbine housing 6 for accommodating a turbine 8, and a bearing housing 5 for accommodating a bearing 30. As shown in FIG. 2, the bearing housing 5 is arranged between the compressor housing 4 and the turbine housing 6 in the axial direction of the rotor 9, and is fixed to the compressor housing 4 and the turbine housing 6 by screwing with bolts or the like. ing.

As shown in FIG. 2, the compressor 7 includes a hub 73 and a plurality of blades 74 provided so as to project outward in the radial direction (direction orthogonal to the axial direction) from the outer circumference of the hub 73. I'm out. As shown in FIG. 2, the hub 73 is formed in a conical shape in which the external dimension gradually increases toward the side away from the near side of the intake inlet 42 in the axial direction. As shown in FIG. 2, the side near the intake inlet 42 in the axial direction of the hub 73, the side where the blade 74 is provided is the front 71, and the side away from the intake inlet 42 in the axial direction of the hub 73 is the back surface. It is 72.

As shown in FIG. 2, the compressor housing 4 extends along the direction orthogonal to the axis CA of the rotor 9 on the outer peripheral side of the compressor 7 and on the side away from the intake inlet 42 in the axial direction. 43 is formed. The compressor housing 4 has a spiral compressor flow path 44 formed on the outer peripheral side of the diffuser 43. Further, the compressor housing 4 is formed with a shroud portion 45 so as to cover the compressor 7. The shroud portion 45 is formed so as to be on the intake inlet 42 side of the diffuser 43 in the axial direction and to be continuous with the diffuser 43.

As shown in FIG. 2, the turbine housing 6 includes an inlet side housing 6A configured to guide the exhaust gas to the turbine 8 and an outlet side housing 6B for discharging the exhaust gas that has passed through the turbine 8. There is. The high-temperature exhaust gas discharged from the engine 10 is introduced from the exhaust inlet 64 formed in the turbine housing 6 and sent to the turbine 8, so that the turbine 8 is rotationally driven around the axis CA. The exhaust gas obtained by rotationally driving the turbine 8 is discharged from the exhaust outlet 66 (gas discharge port) formed in the turbine housing 6.

Since the compressor 7 is connected to the turbine 8 via the rotor 9, the compressor 7 is rotationally driven with the axis CA as the rotation center in synchronization with the rotation of the turbine 8. The combustion gas A is sucked in from the intake inlet 42 of the compressor housing 4 by rotationally driving the compressor 7. The sucked combustion gas A flows inside the compressor housing 4 along the axial direction. The combustion gas A introduced into the compressor housing 4 from the intake inlet 42 is the fresh air I sent to the compressor housing 4 after passing through the air cleaner 15, and the exhaust gas E sent to the compressor housing 4 after passing through the EGR flow path 17. (EGR gas) and an air-fuel mixture containing. In the closed state in which the EGR valve 19 closes the EGR flow path 17, the combustion gas A introduced into the compressor housing 4 is composed of fresh air I containing no EGR gas.

The air-fuel mixture introduced into the compressor housing 4 flows between the plurality of blades 74 of the rotationally driven compressor 7, and after the dynamic pressure is mainly increased, it flows into the diffuser 43 located on the outer side in the radial direction. A part of the dynamic pressure is converted into static pressure and the pressure is increased, and the pressure is sent to the inside of the combustion chamber of the engine 10 through the compressor flow path 44 and the intake outlet 46. At this time, a part of the air-fuel mixture whose pressure has been increased by the compressor 7 passes through a gap formed between the outer peripheral end of the compressor 7 and the portion facing the outer peripheral end of the bearing housing, and the back surface of the compressor 7. It flows into the first space 31 formed on the 72 side.

As shown in FIG. 2, the first space 31 is an internal space facing the back surface 72 of the compressor 7, and is an internal space into which the compressed air-fuel mixture flows into the compressor 7. In the embodiment shown in FIG. 2, the first space 31 is a space surrounded by the back surface 72 of the compressor 7 and the bearing housing 5. More specifically, the first space 31 is a space in which at least a part is defined by the back surface 72 of the compressor 7 and the portion of the bearing housing 5 facing the back surface 72. In another embodiment, the first space 31 is a space surrounded by the back surface 72 of the compressor 7 and the compressor housing 4. More specifically, the first space 31 is a space in which at least a part is defined by a back surface 72 of the compressor 7 and a portion of the compressor housing 4 facing the back surface 72. The first space 31 may be partially defined by a member housed in the compressor housing 4 or the bearing housing 5.

Further, as shown in FIG. 2, the internal space formed inside the turbine housing 6 for flowing the exhaust gas, and the internal space provided between the exhaust inlet 64 and the exhaust outlet 66 is from the turbine 8. The exhaust inlet side space 65, which is an internal space located on the upstream side in the exhaust gas flow direction, and the second space 32 (exhaust outlet side space), which is an internal space located on the downstream side in the exhaust gas flow direction from the turbine 8. And, including. The exhaust gas flowing through the second space 32 consumes energy to rotate the turbine 8, and therefore has a lower pressure than the exhaust gas flowing through the exhaust inlet side space 65.

FIG. 3 is a diagram for explaining a first opening, a second opening, and an air-fuel mixture exhaust flow path in one embodiment of the present invention, and is a schematic configuration diagram schematically showing the configuration of a turbocharger. As shown in FIG. 3, the first opening 52 formed on the outer peripheral surface 51 of the bearing housing 5 communicates with the first space 31 formed on the back surface 72 side of the compressor 7 described above. Further, the second opening 62 formed on the outer peripheral surface 61 of the outlet side housing 6B (turbine housing 6) communicates with the second space 32 formed on the downstream side of the turbine 8 of the turbine housing 6 described above.

In the embodiment shown in FIG. 3, the first opening 52 communicates with the first space 31 via a connection flow path 54 connecting the first opening 52 and the first space 31. Further, in the second opening 62, the second opening 62 and the second space 32 are directly communicated with each other without passing through the connecting flow path. In another embodiment, the first opening 52 and the first space 31 may directly communicate with each other without passing through the connecting flow path, or the second opening 62 and the second space 32 may communicate with each other through the connecting flow path. It may communicate with each other. Further, in another embodiment, the first opening 52 may be formed on the outer peripheral surface 41 of the compressor housing 4.

As shown in FIG. 3, the turbocharger 3 further includes at least one air-fuel mixture exhaust flow path 33 connecting the first opening 52 and the second opening 62. In the embodiment shown in FIG. 3, at least one air-fuel mixture exhaust flow path 33 is formed by a cylindrical pipe 35. The pipe 35 has a U-shaped curved shape, one end of which is attached to the outer peripheral surface 51 of the bearing housing 5 by bolting or the like, and the other end of which is attached to the outer peripheral surface 61 of the turbine housing 6 by bolting or the like. Be done. Then, in the pipe 35, the opening at one end of the pipe 35 communicates with the first opening 52, and the opening at the other end communicates with the second opening 62. Further, as shown in FIG. 3, the pipe 35 is an external pipe provided outside the bearing housing 5 and the turbine housing 6.

As described above, the turbocharger 3 according to some embodiments has a first opening communicating with the above-mentioned compressor housing 4, the above-mentioned bearing housing 5, the above-mentioned turbine housing 6, and the above-mentioned first space 31. It is provided with at least one air-fuel mixture exhaust flow path 33 connecting the 52 and the second opening 62 communicating with the second space 32.

According to the above configuration, during operation of the turbocharger 3, the air-fuel mixture compressed by the compressor 7 and having a high pressure flows into the first space 31 formed on the back surface 72 side of the compressor 7. In the second space 32 formed on the downstream side of the turbine 8 of the turbine housing 6, the exhaust gas that has worked on the turbine 8 and has become low pressure flows. Therefore, due to the pressure difference between the air-fuel mixture in the first space 31 and the exhaust gas in the second space 32, the air-fuel mixture in the first space 31 is the first opening 52 and the second space that communicate with the first space 31. It flows into the second space 32 through at least one air-fuel mixture exhaust flow path 33 connecting to the second opening 62 communicating with the 32. Since the air-fuel mixture exhaust flow path 33 allows the air-fuel mixture in the first space 31 to escape, it is possible to reduce the load on the thrust bearing 37 among the bearings supporting the rotor 9 during operation.

Further, the air-fuel mixture containing the EGR gas that has flowed into the second space 32 is discharged from the exhaust gas outlet 66 of the turbine housing 6 together with the exhaust gas flowing on the downstream side of the turbine 8, and is on the downstream side of the exhaust gas outlet 66 in the flow direction of the exhaust gas. The exhaust gas is treated in the same manner as the exhaust gas by the exhaust gas treatment device 12 for cleaning the exhaust gas provided in. Therefore, it is possible to prevent deterioration of the external environment of the turbocharger 3 due to the air-fuel mixture discharged from the first space 31.

Further, the turbocharger 3 according to the above configuration does not need to newly install a blower device such as a pump or a processing device for processing the air-fuel mixture, and forms the first opening 52 and the second opening 62, and the first opening 52 and the second opening 62 are formed. Since at least one air-fuel mixture exhaust flow path 33 connected to the one opening 52 and the second opening 62 may be provided, the existing equipment is not significantly changed. In addition, there is no need to change existing equipment or piping other than the turbocharger 3. Therefore, the turbocharger 3 described above can be easily changed from the existing equipment, and the existing equipment can be effectively utilized. In particular, when the first opening 52 and the second opening 62 are already formed, it is easier to change from the existing equipment.

FIG. 4 is a diagram for explaining an air-fuel mixture exhaust flow path according to an embodiment of the present invention, and is a schematic external view schematically showing the appearance of the turbocharger. FIG. 5 is a view corresponding to the arrow view of the line BB in FIG. 4, and is a schematic cross-sectional view of the turbine housing in which the gas discharge port is opened vertically upward. FIG. 6 is a view corresponding to the arrow view of the line BB in FIG. 4, and is a schematic cross-sectional view of the turbine housing in which the gas discharge port opens diagonally upward. In some embodiments, as shown in FIG. 4, the above-mentioned pipe 35 has a pipe 35A having one end attached to the outer peripheral surface 51 of the bearing housing 5 and a pipe having one end attached to the outer peripheral surface 61 of the turbine housing 6. 35B includes a pipe 35C connecting the other end of the pipe 35A and the other end of the pipe 35B. In the embodiment shown in FIG. 4, each of the pipes 35A to 35C is formed in a flange shape at both ends, and is fixed to another member such as the bearing housing 5 by being bolted at the flange-shaped portion. It is supposed to be done. In the embodiment shown in FIGS. 5 and 6, the outlet side housing 6B is formed in a U shape in a cross section along the direction orthogonal to the axis.

In some embodiments, as shown in FIGS. 5 and 6, a plurality of drain holes 63 are formed on the outer peripheral surface 61 of the turbine housing 6 described above at intervals in the circumferential direction. The above-mentioned second opening 62 is composed of at least one of a plurality of drain holes 63. The drain hole 63 is a hole for draining drain from the inside of the turbine housing 6 to the outside, and is a hole formed at the time of manufacturing the turbine housing 6. As shown in FIGS. 5 and 6, a drain pipe 36 is connected to one of the plurality of drain holes 63. The drain is discharged to the outside of the turbine housing 6 via the drain pipe 36. Further, at least one of the plurality of drain holes 63 is connected to the pipe 35B as the second opening 62. Further, of the plurality of drain holes 63, the remaining drain holes are closed.

Generally, as shown in FIGS. 5 and 6, the turbine housing 6 is configured so that the mounting angle can be changed according to the position and orientation of the chimney that discharges the exhaust gas to the outside. In other words, the turbine housing 6 is configured so that the mounting angle with respect to the bearing housing 5 can be changed so that the exhaust outlet 66 is at a position suitable for the position and orientation of the chimney. As shown in FIGS. 5 and 6, the outer peripheral surface 51 of the turbine housing 6 is spaced in the circumferential direction so that the drain can be appropriately discharged from the inside of the turbine housing 6 even if the mounting angle of the turbine housing 6 is changed. Is opened to form a plurality of drain holes 63. According to the above configuration, since the second opening 62 is composed of at least one of the plurality of drain holes 63, the existing turbine housing provided with the plurality of drain holes 63 can be utilized. Further, between at least a part (pipe 35B) of the parts constituting the air-fuel mixture exhaust flow path 33 and a connection part (drain pipe 36) connected to the drain hole for draining the drain. It is possible to standardize parts.

In some embodiments, as shown in FIGS. 5 and 6, the plurality of drain holes 63 described above include a lowermost drain hole 63A located at the lowermost position in the vertical direction and a drain hole other than the lowermost drain hole 63A. It includes an upper drain hole 63B, which is 63. The above-mentioned second opening 62 is composed of at least one of the upper drain holes 63B. A drain pipe 36 is connected to the lowermost drain hole 63A. Further, at least one of the plurality of upper drain holes 63B is connected to the pipe 35B as the second opening 62. In this case, by making the second opening 62 a drain hole 63 (upper side drain hole 63B) other than the lowermost drain hole 63A located at the lowermost position in the vertical direction, the drain passes through the second opening 62. It is possible to prevent the air-fuel mixture exhaust flow path 33 from entering the air-fuel mixture exhaust flow path 33.

In some embodiments, as shown in FIGS. 5 and 6, the plurality of drain holes 63 described above are the drains on the outlet side located closest to the exhaust outlet 66 (gas outlet) of the turbine housing 6. Includes hole 63C. The above-mentioned second opening 62 is composed of a drain hole 63C on the discharge port side. A pipe 35B is connected to the drain hole 63C on the discharge port side as a second opening 62. In this case, the second opening 62 is the drain hole 63C on the discharge port side located closest to the exhaust outlet 66 of the turbine housing 6, so that the other drain hole 63 is the second opening 62. Also, the second opening 62 can be located away from the turbine 8. Therefore, it is possible to prevent the influence of the turbulence of the flow of the exhaust gas flowing through the second space 32, which is caused by the air-fuel mixture flowing from the second opening 62 into the second space 32, from propagating to the turbine 8.

In some embodiments, as shown in FIG. 3, the turbocharger 3 described above is a check valve 34 provided in the middle of the air-fuel mixture exhaust flow path 33, from the second space 32 to the first space 31. A check valve 34 is further provided to prevent the exhaust gas from flowing toward the surface. In this case, even if the pressure of the exhaust gas in the second space 32 becomes higher than the pressure of the air-fuel mixture in the first space 31, the check valve 34 causes the exhaust gas from the second space 32 toward the first space 31. Can be prevented from flowing. Here, the exhaust gas flowing inside the turbine housing 6 contains a corrosive component such as sulfur oxide (SOx). Therefore, the turbocharger 3 provided with the check valve 34 described above can prevent the member facing the first space 31 such as the compressor 7 from being corroded or damaged by the corrosive component contained in the exhaust gas. In the air-fuel mixture containing EGR gas introduced from the intake inlet 42 of the compressor housing 4, corrosive components such as sulfur oxides (SOx) have been removed by the exhaust gas treatment device 12. Further, when the pressure of the exhaust gas in the second space 32 becomes higher than the pressure of the air-fuel mixture in the first space 31, for example, in order to send the combustion gas A to the engine 10 during low load operation of the engine 10. When an auxiliary blower (not shown) is activated on the downstream side of the turbocharger 3 of the intake flow path 13, the combustion gas A flows back due to surging, and the pressure on the compressor 7 (first space 31) side drops. There is a case where it is done.

In some embodiments, as shown in FIG. 3, at least one air vent hole 53 is formed on the outer peripheral surface 51 of the bearing housing 5 described above. The first opening 52 described above is composed of an air vent hole 53. The air vent hole 53 is a hole for discharging the high-pressure gas that has flowed into the first space 31 into the atmosphere. Some of the existing bearing housings have an existing air vent 53. As shown in FIG. 3, the pipe 35 is connected to the air vent hole 53. In this case, since the first opening 52 is composed of the air vent hole 53, the existing bearing housing in which the air vent hole 53 is already installed can be utilized.

The present invention is not limited to the above-described embodiment, and includes a modification of the above-mentioned embodiment and a combination of these embodiments as appropriate.

For example, in some of the above-described embodiments, the turbocharger 3 is provided in the marine diesel engine 1 (marine internal combustion engine), but may be provided in a non-marine internal combustion engine.

1 Diesel engine 10 Engine 11 EGR system 12 Exhaust gas treatment device 13 Intake flow path 14 Exhaust flow path 15 Air cleaner 16 Air cooler 17 EGR flow path 3 Turbocharger 30 Bearing 31 First space 32 Second space 33 Air-fuel mixture exhaust flow path 34 Non-return Valve 35 Pipe 35A Compressor side pipe 35B Turbine side pipe 35C Connection pipe 36 Drain pipe 37 Thrust bearing 4 Compressor housing 41 Outer surface 42 Intake port 43 Diffuser 44 Compressor flow path 45 Shroud part 46 Intake outlet 5 Bearing housing 51 Outer surface 52 First Opening 53 Air vent 54 Connection flow path 6 Turbine housing 6A Inlet side housing 6B Outlet side housing 61 Outer peripheral surface 62 Second opening 63 Drain hole 63A Lowermost drain hole 63B Upper side drain hole 63C Outlet side drain hole 64 Exhaust inlet 65 Exhaust inlet side space 66 Exhaust outlet 7 Compressor 71 Front 72 Back 73 Hub 74 Blade 8 Turbine 9 Rotor A Combustion gas E Exhaust gas I Fresh air

Claims (6)

A turbocharger configured to supercharge an air-fuel mixture containing EGR gas.
A compressor housing that houses the compressor that compresses the air-fuel mixture, and
A turbine housing that houses a turbine connected to the compressor via a rotor, and
A bearing housing that houses a bearing that rotatably supports the rotor,
A first opening formed on the outer peripheral surface of the compressor housing or the bearing housing, which communicates with the first space formed on the back surface side of the compressor, and
A second opening formed on the outer peripheral surface of the turbine housing and communicating with a second space formed on the downstream side of the turbine of the turbine housing.
With at least one air-fuel mixture exhaust flow path to connect ,
The at least one air-fuel mixture exhaust flow path discharges the air-fuel mixture that has flowed into the first space into the second space due to the pressure difference between the air-fuel mixture in the first space and the exhaust gas in the second space. Turbocharger configured as . A plurality of drain holes are formed on the outer peripheral surface of the turbine housing at intervals in the circumferential direction.
The turbocharger according to claim 1, wherein the second opening comprises at least one of the plurality of drain holes. The plurality of drain holes include a lowermost drain hole located at the lowermost position in the vertical direction and an upper drain hole which is a drain hole other than the lowermost drain hole.
The turbocharger according to claim 2, wherein the second opening comprises at least one of the upper drain holes. The plurality of drain holes include a drain hole on the discharge port side located closest to the gas discharge port of the turbine housing.
The turbocharger according to claim 2, wherein the second opening is a drain hole on the discharge port side. Any of claims 1 to 4, which is a check valve provided in the middle of the air-fuel mixture exhaust flow path and further includes a check valve for preventing exhaust gas from flowing from the second space toward the first space. Or the turbocharger described in item 1. The turbocharger according to any one of claims 1 to 5, wherein the at least one air-fuel mixture exhaust flow path is formed by a pipe provided outside the compressor housing, the turbine housing, and the bearing housing.

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