JP7143234B2 - Supercharger casing and supercharger provided with the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a supercharger casing and a supercharger having the same.

Marine internal combustion engines, power generation internal combustion engines, etc. (for example, diesel engines) are required to improve their performance when operating at low loads. In order to improve performance when operating at low load, it is desirable to set the boost pressure of the turbocharger mounted on the internal combustion engine higher. Supply pressure becomes too high. Therefore, when the internal combustion engine operates at a high load and the amount of exhaust gas is large, a so-called exhaust gas bypass system is used to prevent the supercharging pressure from rising excessively by allowing the exhaust gas to bypass the turbocharger turbine. It has been put to practical use.

As a turbocharger employing an exhaust gas bypass system, there is a turbocharger disclosed in Patent Document 1, for example. According to this supercharger, exhaust gas bypasses the turbine through a U-shaped bypass pipe provided with an on-off valve.

Another example of a turbocharger that employs an exhaust gas bypass system is the turbocharger disclosed in Patent Document 2, for example. According to this supercharger, exhaust gas bypasses the turbine by means of a pipe (so-called shrimp pipe) formed in an arc shape as a whole by connecting pipes cut at an angle.

Japanese Patent No. 6165564 JP 2013-124626 A

However, in the U-shaped bypass pipe of the supercharger disclosed in Patent Document 1, a predetermined space must be secured in order to form the two bent portions. It is difficult to apply to the turbocharger of Also, even if it is applied to a small turbocharger, it may be difficult to secure the passage area of the connecting portion between the outlet end of the bypass pipe and the casing due to the shape of the casing and other parts. .

In addition, the turbocharger bypass pipe disclosed in Patent Document 2 may increase the time and cost required for manufacturing due to its structure.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and is applicable to a small turbocharger having a limited layout. An object of the present invention is to provide a turbocharger with

In order to solve the above problems, the turbocharger casing and the turbocharger having the casing of the present invention employ the following means.
That is, the turbocharger casing according to one aspect of the present invention forms an exhaust gas passage through which exhaust gas discharged from the internal combustion engine flows, and a turbine driven by the exhaust gas flowing through the exhaust gas passage. A turbocharger casing that houses a bypass pipe that communicates the exhaust gas flow path on the exhaust gas inlet side and the exhaust gas flow path on the exhaust gas outlet side without passing through the turbine, the bypass pipe is connected to the exhaust gas inlet side and is composed of a straight pipe having a straight flow passage, and an elbow pipe having a curved flow passage connected to the straight pipe and the exhaust gas outlet side.

According to the turbocharger casing according to this aspect, the bypass pipe is provided with one bent portion (only the bent portion of the elbow pipe), so the number of bent portions can be reduced compared to the conventional structure. , can be applied to small turbochargers with layout restrictions.
Moreover, since the bypass pipe has a simple structure composed of two members (a straight pipe and an elbow pipe), it is possible to reduce the time and cost required for manufacturing.

Further, in the turbocharger casing according to one aspect of the present invention, the elbow pipe has a substantially circular cross section along the axis, and a connection portion connecting the elbow pipe and the exhaust gas flow path communicates with each other. The shape of the channel changes from the substantially circular shape to a flat shape while keeping the channel area substantially constant.

According to the casing of the turbocharger according to this aspect, the shape of the connecting flow passage changes from a substantially circular shape matching the elbow pipe to a flat shape while keeping the flow passage area substantially constant. As a result, even if there are restrictions on dimensions in a predetermined direction due to, for example, the shape of the casing on the exhaust gas outlet side or the relationship with other parts, a flat shape that is thinner in a predetermined direction ensures a flow passage area. be able to.

Further, in the turbocharger casing according to one aspect of the present invention, the connection flow path is formed by casting.

According to the casing of the supercharger according to this aspect, it is possible to easily form the connection passage having a complicated shape.

Further, in the turbocharger casing according to one aspect of the present invention, the bypass pipe includes an on-off valve whose opening and closing is controlled by a signal from the outside.

According to the turbocharger casing according to this aspect, the opening/closing state of the opening/closing valve provided in the bypass pipe is controlled by a signal transmitted from, for example, the control unit of the internal combustion engine in which the turbocharger is mounted. As a result, the flow rate of the exhaust gas flowing through the bypass pipe can be controlled appropriately according to the specifications and conditions of the internal combustion engine.

Further, in the turbocharger casing according to one aspect of the present invention, the straight pipe is arranged such that the axial direction substantially coincides with the inflow direction of the exhaust gas flowing in from the exhaust gas inlet.

According to the turbocharger casing according to this aspect, the exhaust gas that has flowed in from the exhaust gas inlet is guided to the bypass pipe without being diverted. Therefore, the pressure loss of the exhaust gas guided to the bypass pipe can be suppressed.

Further, in the turbocharger casing according to one aspect of the present invention, the straight pipe includes an expandable portion that expands and contracts in the axial direction.

According to the turbocharger casing according to this aspect, the straight pipe can be expanded and contracted in the axial direction, so that thermal expansion and thermal contraction occurring in the bypass pipe due to the flow of the exhaust gas can be absorbed.
When the bypass pipe is provided with an on-off valve, it is preferable that the expansion/contraction portion be installed downstream of the on-off valve in the flow direction of the exhaust gas.

Further, the turbocharger casing according to one aspect of the present invention forms an exhaust gas passage through which the exhaust gas discharged from the internal combustion engine flows, and is driven by the exhaust gas flowing through the exhaust gas passage. A turbocharger casing housing a turbine, comprising a bypass pipe that communicates the exhaust gas flow path on the exhaust gas inlet side and the exhaust gas flow path on the exhaust gas outlet side without passing through the turbine, wherein the bypass The pipe has a substantially circular cross-sectional area along the axis, and the connection flow path that connects the connecting portion with the bypass pipe and the exhaust gas flow path has a cross-sectional area that is substantially reduced from the substantially circular flow path shape. It changes to a flat shape while keeping constant.

According to the casing of the turbocharger according to this aspect, the connection flow path that connects the connecting portion with the bypass pipe and the exhaust gas flow path through which the exhaust gas flows is maintained at a substantially constant flow path area. The shape has changed from a substantially circular shape that matches the bypass pipe to a flat shape. As a result, even if there are restrictions on dimensions in a predetermined direction due to, for example, the shape of the casing on the exhaust gas outlet side or the relationship with other parts, a flat shape that is thinner in a predetermined direction ensures a flow passage area. be able to.

Further, a turbocharger according to an aspect of the present invention includes the turbocharger casing described above and the turbine driven by exhaust gas discharged from an internal combustion engine.

Advantageous Effects of Invention According to the present invention, it is possible to provide a turbocharger casing having a bypass pipe of a simple structure and a turbocharger having the same, which can be applied to a small-sized turbocharger with layout restrictions.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal sectional view of a supercharger casing and a supercharger including the same according to an embodiment of the present invention; FIG. 2 is a partially enlarged view of the A portion shown in FIG. 1, and is a perspective view showing the shape of the outlet-side connecting channel.

1 and 2, a turbocharger casing and a turbocharger including the same according to an embodiment of the present invention will be described below.

First, the structure of the turbocharger 1 provided with the casing 10 and the casing 10 is demonstrated.
As shown in FIG. 1, the supercharger 1 compresses combustion air supplied to an internal combustion engine mounted on a ship or the like, forcing high-density air into the combustion chamber of the internal combustion engine. It is configured to send The casing 10 according to this embodiment is particularly suitable for use in a small turbocharger.

The turbocharger 1 includes a turbine 30 driven by exhaust gas discharged from an internal combustion engine (not shown), a rotor shaft 33 driven to rotate about an axis X by the turbine 30, and housing them and exhaust gas. and a casing 10 forming a flow path (exhaust gas flow path 12).

The turbine 30 is an axial flow turbine that includes a turbine disk 31 to which rotor blades 32 are attached and a nozzle ring 34 to which guide vanes 34a are attached.

The rotor blades 32 are arranged in the exhaust gas flow path 12 so as to be close to the downstream ends of guide vanes 34 a (described later) along the axis X direction, and are provided on one end of the rotor shaft 33 . A plurality of them are attached to the periphery.
The exhaust gas passage 12 on the upstream side of the moving blades 32 in the flow direction of the exhaust gas is indicated by reference numeral 12a, and the exhaust gas passage 12 on the downstream side of the moving blades 32 is indicated by reference numeral 12b.

The nozzle ring 34 includes a cylindrical outer ring 34c extending in the direction of the axis X, an inner ring 34b having a smaller diameter than the outer ring 34c, and a ring between the outer ring 34c and the inner ring 34b. and attached guide vanes 34a.

The nozzle ring 34 is attached to the casing 10 so that the outer ring 34c and the inner ring 34b form part of the wall forming the exhaust gas flow path 12a along the axis X direction. At this time, the casing 10 is divided into front and rear portions of the nozzle ring 34 along the axis X direction.

A plurality of guide vanes 34a are attached in the circumferential direction of the axis X between the inner peripheral wall of the outer peripheral ring 34c and the outer peripheral wall of the inner peripheral ring 34b.
The guide vanes 34a are wing-shaped members for appropriately guiding the exhaust gas toward the rotor blades 32 by adjusting the flow velocity and direction of the exhaust gas flowing toward the rotor blades 32 in the exhaust gas passage 12a. be.

The turbine 30 rotates the turbine disk 31 and the rotor shaft 33 as the high-temperature exhaust gas that has passed through the guide vanes 34 a passes through the moving blades 32 and expands. An impeller (not shown) of a compressor (not shown) is provided at the other end of the rotor shaft 33, and when the rotor shaft 33 is rotationally driven, the impeller is rotationally driven and air is discharged. Compressed.

The casing 10 has a gas inlet 12A (exhaust gas inlet) formed in the lower portion and opened downward, and a gas outlet 12B (exhaust gas outlet) formed in the upper portion and opened upward. The casing 10 forms an exhaust gas flow path 12 (12a, 12b, 12c) that communicates the gas inlet 12A and the gas outlet 12B via 30. The casing 10 surrounds a part of the turbine 30 and the rotor shaft 33. are housed in

Further, the casing 10 includes a bypass pipe 50 that forms a flow path (bypass flow path 51) that communicates the exhaust gas flow path 12a on the side of the gas inlet 12A and the exhaust gas flow path 12c on the side of the gas outlet 12B without passing through the turbine 30. It has

The bypass pipe 50 is a straight pipe having an L-shape extending from the gas inlet 12A side to the gas outlet 12B side when viewed from the side as shown in FIG. 52, and one elbow pipe 54 having a channel (curved channel 55) whose axis is bent at a substantially right angle. As a result, the bypass pipe 50 can be provided with only one bent portion, so that it can be applied to a small turbocharger 1 with a limited layout. Also, the bypass pipe 50 can have a simple structure composed of two members (a straight pipe 52 and an elbow pipe 54).
It is preferable that the straight pipe 52 and the elbow pipe 54 have a substantially circular shape along the axis.

One end of the straight pipe 52 is connected to the casing 10 forming the exhaust gas flow path 12a on the side of the gas inlet 12A.
An inlet-side connection channel 16 that communicates the exhaust gas channel 12 a with the outside of the casing 10 is formed in the portion of the casing 10 to which the straight pipe 52 is connected. The inlet-side connection channel 16 has an axis in the inflow direction of the exhaust gas (arrow Gi in the figure) flowing from the gas inlet 12A.
The straight pipe 52 is arranged with respect to the casing 10 so that the axis of the straight flow path 53 is positioned on the extension of the axis of the inlet-side connection flow path 16 . That is, the axial direction of the straight flow path 53 matches the inflow direction of the exhaust gas flowing in from the gas inlet 12A. As a result, the exhaust gas that has flowed in from the gas inlet 12A is guided to the bypass passage 51 without being diverted.

One end of the elbow pipe 54 is connected to the other end of the straight pipe 52 (an end different from the end connected to the casing 10). The other end of the elbow pipe 54 is connected to the casing 10 forming the exhaust gas flow path 12c on the side of the gas outlet 12B.
An outlet-side connection channel 18 (connection channel) that communicates the outside of the casing 10 with the exhaust gas channel 12c is formed in the portion of the casing 10 to which the elbow pipe 54 is connected.
As described above, the elbow pipe 54 has its axis smoothly bent substantially at a right angle, so that the axial direction of the outlet-side connection flow path 18 and the axial direction of the straight flow path 53 are substantially perpendicular to each other.

As shown in FIGS. 1 and 2 , the shape of the outlet-side connection channel 18 is substantially circular at the connection portion 14 with the elbow pipe 54 , matching the shape of the channel of the elbow pipe 54 . Further, the shape of the outlet-side connection flow path 18 changes into a flat shape in which the width direction is expanded and the height direction is reduced from the connection portion 14 side toward the exhaust gas flow path 12c side.
At this time, the shape is changed from the connection portion 14 side toward the exhaust gas flow path 12c side so that the flow path area of the outlet side connection flow path 18 is kept substantially constant. As a result, even if there are restrictions on the size in the height direction due to, for example, the shape of the casing 10 on the side of the gas outlet 12B or the relationship with other parts, the flat shape that is thinner in the height direction can be used. Area can be secured.
The portion of the casing 10 that forms the outlet-side connection channel 18 may be manufactured by casting. This makes it possible to easily form the outlet-side connecting channel 18 having a complicated shape.

As shown in FIG. 1, the straight pipe 52 described above is provided with an on-off valve 60 whose degree of opening can be controlled.
The opening degree of the on-off valve 60 is controlled by a signal from a control unit (not shown) that controls the internal combustion engine in which the supercharger 1 is mounted, for example. Thereby, the flow rate of the exhaust gas flowing through the bypass flow path 51 can be adjusted.
The mounting position of the on-off valve 60 can be changed as appropriate, and may be mounted on the elbow pipe 54, for example.

Further, the straight tube 52 described above may be provided with an expansion 62 (expandable portion) that expands and contracts in the axial direction. The expansion 62 can absorb expansion and contraction of the straight tube 52 in the axial direction. As a result, thermal expansion and thermal contraction occurring in the bypass pipe 50 can be absorbed.
When the on-off valve 60 is attached to the straight pipe 52 , the expansion 62 is preferably attached to the straight pipe 52 on the downstream side of the on-off valve 60 (on the side of the outlet-side connection flow path 18 ). This allows the on-off valve 60 to be easily attached to the casing 10 . The attachment position of the expansion 62 can be changed as appropriate, and may be attached to the straight pipe 52 on the upstream side of the on-off valve 60 .

Next, the flow of exhaust gas will be described.
[When the on-off valve is closed]
In order to improve the performance of the supercharger even when the internal combustion engine in which the supercharger 1 is mounted operates at a low load, for example, a nozzle ( Nozzles smaller than normal designs) may be selected. If part of the exhaust gas is bypassed by the bypass pipe 50 at such a low load, the output of the turbine 30 is reduced by the bypassed exhaust gas, and the desired boost pressure cannot be obtained. Therefore, when the load is low, the on-off valve 60 is closed so that the exhaust gas does not flow through the bypass passage 51 .

When the on-off valve 60 is in a closed state, all the exhaust gas flowing from the gas inlet 12A drives the turbine 30 while flowing through the exhaust gas flow path 12a and the exhaust gas flow path 12b to flow through the exhaust gas flow path 12c. It flows out from the outlet 12B (arrow Go in the figure).

[When the on-off valve is open]
In order to improve the performance of the supercharger even when the internal combustion engine in which the supercharger 1 is mounted operates at a low load, for example, a nozzle ( Nozzles smaller than normal designs) may be selected. However, when such an internal combustion engine operates under a high load, the supercharging pressure of the supercharger 1 becomes too high. Therefore, when the load is high, the on-off valve 60 is opened so that the exhaust gas flows through the bypass passage 51 in order to intentionally reduce the output of the turbine 30 . The “open state” referred to here includes not only a state where the degree of opening is 100% (fully open state), but also a state where the degree of opening is greater than 0% and less than 100%.

When the on-off valve 60 is open, part of the exhaust gas flowing from the gas inlet 12A drives the turbine 30 while flowing through the exhaust gas flow path 12a and the exhaust gas flow path 12b, and flows through the exhaust gas flow path 12c. It flows out from the gas outlet 12B.

On the other hand, the other exhaust gas is guided from the exhaust gas flow path 12a to the straight flow path 53 (to the bypass flow path 51) via the inlet side connection flow path 16 (arrow Bi in the drawing).

The exhaust gas guided to the straight flow path 53 is guided to the outlet side connection flow path 18 after reaching the curved flow path 55 and being deflected.

The exhaust gas guided to the outlet-side connection channel 18 passes through the space S1 formed by the outer peripheral wall of the outer ring 34c and the casing 10, and is guided to the exhaust gas channel 12c on the side of the gas outlet 12B ( Arrow Bo) in the figure.

After that, it merges with the exhaust gas that drives the turbine 30 and flows out from the gas outlet 12B (arrow Go in the figure).

Note that if the on-off valve 60 is abruptly operated when the on-off valve 60 is moved from the open state to the closed state, the flow rate of the exhaust gas flowing into the turbine 30 increases sharply, and the output of the turbine 30 accompanies this. increases sharply. At the same time, the speed of the compressor impeller (not shown) will increase sharply. Then, surging may occur in the compressor.
Therefore, in order to avoid surging in the compressor, it is preferable to close the on-off valve 60 gradually. For example, when operating the on-off valve 60 from the fully open state to the fully closed state, it is preferable that the operation takes five seconds or longer.
Needless to say, the operating time of the on-off valve 60 can be appropriately changed according to the specifications of each device. However, it is preferable that the time for operating the on-off valve 60 from the open state to the closed state is longer than the time for operating the on-off valve 60 from the closed state to the open state.

Further, even if the movable parts of the supercharger 1 (the turbine 30, the rotor shaft 33, the compressor (not shown), etc.) fail, the internal combustion engine must be kept in operation. The exhaust gas supplied to 12 cannot be shut off. Therefore, a mechanism for locking the movable part may be provided in order to avoid further damage to the movable part. In the case of this embodiment, since the bypass pipe 50 is installed on the turbine 30 side, it is preferable to provide a lock mechanism on the compressor side in consideration of the ease of access by the operator.

This embodiment has the following effects.
The bypass pipe 50 provided in the casing 10 has only one bent portion, which is the elbow pipe 54. Therefore, it can be applied to a small-sized supercharger 1 with a limited layout. Moreover, the pressure loss caused by the bent portion can be suppressed compared to the case where there are, for example, two bent portions. Furthermore, since the bypass pipe 50 has a simple structure composed of two members (the straight pipe 52 and the elbow pipe 54), it is possible to reduce the time and cost required for manufacturing.

In addition, the shape of the outlet-side connection channel 18 is changed from a substantially circular shape that matches the elbow pipe 54 to a flat shape while keeping the channel area substantially constant. As a result, even if there are restrictions on dimensions in a predetermined direction due to, for example, the shape of the casing 10 on the side of the gas outlet 12B or the relationship with other parts, the flow path area can be reduced by forming a flat shape that is thinner in a predetermined direction. can be secured.

The opening/closing state of the opening/closing valve 60 provided in the bypass pipe 50 is controlled by a signal transmitted from, for example, a control unit of the internal combustion engine in which the supercharger 1 is mounted. As a result, the flow rate of the exhaust gas flowing through the bypass passage 51 can be controlled in accordance with the specifications and conditions of the internal combustion engine.

Further, the axial direction of the straight flow path 53 coincides with the inflow direction of the exhaust gas flowing in from the gas inlet 12A. As a result, the exhaust gas that has flowed in from the gas inlet 12A is guided to the bypass passage 51 without being diverted. Therefore, the pressure loss of the exhaust gas guided to the bypass pipe can be suppressed.

Further, the straight tube 52 is provided with an expansion 62 that expands and contracts in the axial direction. This makes it possible to absorb the thermal expansion and thermal contraction that occur in the bypass pipe 50 due to the circulation of the exhaust gas.

The shape of the bypass pipe 50 is not limited to that of the above-described embodiment, and may be arbitrarily changed according to the specifications of the internal combustion engine and supercharger, and the layout of each device (not shown).

Further, in the above-described embodiments, the description is made using the axial flow turbine, but the present invention can also be applied to rotating machines such as power turbines.

1 Turbocharger 10 Casing 12 (12a, 12b, 12c) Exhaust gas passage 12A Gas inlet 12B Gas outlet 14 Connection portion 16 Inlet side connection passage 18 Outlet side connection passage 30 Turbine 31 Turbine disk 32 Rotor blade 33 Rotor shaft 34 Nozzle ring 34a Guide vane 34b Inner ring 34c Outer ring 50 Bypass pipe 51 Bypass channel 52 Straight pipe 53 Straight channel 54 Elbow pipe 55 Curved channel 60 On-off valve 62 Expansion

Claims (7)

A turbocharger casing that forms an exhaust gas flow path through which exhaust gas emitted from an internal combustion engine flows and houses a turbine that is driven by the exhaust gas that flows through the exhaust gas flow path,
A bypass pipe that communicates the exhaust gas flow path on the exhaust gas inlet side and the exhaust gas flow path on the exhaust gas outlet side without passing through the turbine,
The bypass pipe includes a straight pipe that is connected to the exhaust gas inlet side and has a linear flow path, an elbow pipe that is connected to the straight pipe and the exhaust gas outlet side and has a curved flow path, consists of
The elbow pipe has a substantially circular cross section along the axis,
A casing of a turbocharger , wherein a shape of a connection passage for communicating a connecting portion with the elbow pipe and the exhaust gas passage is changed from the substantially circular shape to a flat shape while keeping the passage area substantially constant . A casing for a turbocharger according to claim 1 , wherein the connecting passage is formed by casting. 2. The turbocharger casing according to claim 1, wherein the bypass pipe includes an on-off valve whose opening and closing is controlled by a signal from the outside. 2. The turbocharger casing according to claim 1, wherein the straight pipe is arranged such that the axial direction substantially coincides with the inflow direction of the exhaust gas flowing in from the exhaust gas inlet. 5. The turbocharger casing according to any one of claims 1 to 4 , wherein the straight pipe has an expandable portion that expands and contracts in the axial direction. A turbocharger casing that forms an exhaust gas flow path through which exhaust gas emitted from an internal combustion engine flows and houses a turbine that is driven by the exhaust gas that flows through the exhaust gas flow path,
A bypass pipe that communicates the exhaust gas flow path on the exhaust gas inlet side and the exhaust gas flow path on the exhaust gas outlet side without passing through the turbine,
The bypass pipe has a substantially circular cross-sectional area along the axis,
A casing of a supercharger in which a connection passage connecting a connecting portion with the bypass pipe and the exhaust gas passage is changed in shape from the substantially circular shape to a flat shape while keeping the cross-sectional area substantially constant. . A turbocharger casing according to claim 1 or 6 ;
the turbine driven by the exhaust gas;
turbocharger with.

Images