JP2019090353A - Marine diesel engine - Google Patents

Abstract

To provide a marine diesel engine which enables reduction of loss of energy of exhaust gas which becomes a power source of turbines of each supercharger.SOLUTION: A marine diesel engine which is one aspect of the invention includes: an engine body which causes a fuel to be burned to output propulsion power of a ship from an output shaft; a first supercharger having a radial turbine which receives exhaust gas discharged from the engine body to rotate; a second supercharger having an axial flow turbine which receives the exhaust gas sent from the radial turbine to rotate; and a circulation pipe disposed between the radial turbine and the axial flow turbine. The radial turbine and the axial flow turbine are disposed so as to face each other in a rotation axis direction of the radial turbine. The circulation pipe causes the exhaust gas to circulate from the radial turbine to the axial flow turbine.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a marine diesel engine mounted on a ship.

Conventionally, in the field of ships, a marine diesel engine to which a plurality of superchargers such as a two-stage supercharger are applied is known as a means for improving the output of the engine body and the fuel efficiency. For example, in Patent Documents 1 and 2, the combustion gas such as air is compressed in two stages and fed to the engine body by rotating the compressor together with the turbine using the exhaust gas discharged from the engine body as a power source. A two-stage turbocharged diesel engine equipped with a high pressure turbocharger and a low pressure turbocharger is disclosed.

The diesel engine described in Patent Document 1 has a structure in which a high-pressure stage turbocharger and a low-pressure stage turbocharger are integrated on one side of an engine body. In this diesel engine,
The low pressure supercharger is disposed close to one side of the engine main body in consideration of being large and heavy as compared with the high pressure supercharger. The high-pressure stage turbocharger is disposed side by side with the low-pressure stage turbocharger (that is, in a direction perpendicular to the rotational axes of the turbine and the compressor) with a distance from the one side of the engine body to the outside. It is done.

The diesel engine described in Patent Document 2 has a structure in which a high-pressure stage turbocharger and a low-pressure stage turbocharger are distributed to both end surfaces in the width direction of the engine body. In this diesel engine, the high-pressure stage turbocharger and the low-pressure stage turbocharger are disposed side by side in a state of being separated from each other by the width dimension of the engine body.

Patent No. 6109040 Patent No. 6109041

By the way, the exhaust gas generated in the engine body is sequentially discharged to the turbines of the high-pressure stage turbocharger and the low-pressure stage turbocharger through piping in order to drive the high-pressure stage turbocharger and the low-pressure stage turbocharger. In this process, the heat dissipation and pressure loss of the exhaust gas tend to increase with the flow of the exhaust gas through the piping. For this reason, it is preferable to shorten the piping of the exhaust gas from the viewpoint of reducing the heat radiation and pressure loss of the exhaust gas that is the motive power source of the turbine (hereinafter collectively referred to as “energy loss”).

However, in the prior art described in Patent Documents 1 and 2, shortening of the exhaust gas pipe is restricted due to the above-mentioned arrangement relationship between the high-pressure stage turbocharger and the low-pressure stage turbocharger. For example, in the prior art described in Patent Document 1, since the high-pressure stage turbocharger and the low-pressure stage turbocharger are arranged side by side separately from each other, piping connecting these turbines to each other is used. It is difficult to shorten. In particular, in the prior art described in Patent Document 2, since the high-pressure stage turbocharger and the low-pressure stage turbocharger are disposed apart from each other by the width dimension of the engine body, piping for connecting these turbines It is extremely difficult to shorten. Therefore, in the prior art described in Patent Documents 1 and 2, it is difficult to reduce the energy loss of the exhaust gas that becomes the power source of the turbine of each supercharger exemplified by the high pressure supercharger and the low pressure supercharger. It is.

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a marine diesel engine capable of reducing the energy loss of the exhaust gas that is the power source of the turbine of each turbocharger.

In order to solve the problems described above and to achieve the object, a marine diesel engine according to the present invention comprises an engine body which burns fuel and outputs propulsion power of a ship from an output shaft, and exhaust gas discharged from the engine body A first turbocharger having a radial turbine that rotates in response to
A second supercharger having an axial flow turbine disposed so as to face the radial turbine in the rotational axis direction of the radial turbine and receiving and rotating the exhaust gas delivered from the radial turbine; and the radial turbine And a flow pipe disposed between the radial flow turbine and the axial flow turbine and disposed between the radial flow turbine and the axial flow turbine.

The marine diesel engine according to the present invention is characterized in that, in the above-mentioned invention, an exhaust pipe for discharging the exhaust gas in a radial direction of the radial turbine from the engine body toward the radial turbine.

The marine diesel engine according to the present invention is characterized in that, in the above invention, the rotary shaft of the radial turbine and the rotary shaft of the axial flow turbine are located on the same axis.

The marine diesel engine according to the present invention is characterized in that, in the above invention, the rotary shaft of the radial turbine and the rotary shaft of the axial flow turbine are parallel to the output shaft of the engine body. Do.

In the marine diesel engine according to the present invention, in the above-mentioned invention, a first cooler for cooling a combustion gas compressed by a compressor of the second turbocharger, and the first turbocharger. A second cooler for cooling the combustion gas further compressed by the compressor of
The second supercharger is disposed above the first cooler, and the first supercharger is disposed above the second cooler.

In the marine diesel engine according to the present invention, in the above-mentioned invention, the engine body includes an exhaust manifold, and the first and second turbochargers are compared with the exhaust manifold. It is characterized in that it is disposed below the height direction of the engine body.

In the marine diesel engine according to the present invention, in the above invention, the flow pipe may be
A telescopic tube which can be expanded and contracted in the rotation axis direction is provided.

The marine diesel engine according to the present invention is characterized in that, in the above-mentioned invention, the second supercharger is a large-sized supercharger as compared with the first supercharger.

According to the present invention, it is possible to reduce the energy loss of the exhaust gas that becomes the power source of the turbine of each turbocharger.

FIG. 1 is a schematic view showing an example of the configuration of a marine diesel engine according to an embodiment of the present invention. FIG. 2 is a schematic view showing an example of the arrangement configuration of the high-pressure stage turbine and the low-pressure stage turbine according to the embodiment of the present invention.

Hereinafter, preferred embodiments of a marine diesel engine according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited by the present embodiment.
In addition, it should be noted that the drawings are schematic, and dimensional relationships among elements, ratios of elements, and the like may differ from actual ones. Even between the drawings, there may be a case where the dimensional relationships and ratios differ from one another. Further, in the drawings, the same components are denoted by the same reference numerals.

(Composition of marine diesel engine)
First, the configuration of a marine diesel engine according to an embodiment of the present invention will be described. Figure 1
FIG. 1 is a schematic view showing one configuration example of a marine diesel engine according to an embodiment of the present invention. As shown in FIG. 1, a marine diesel engine 10 according to the present embodiment includes an engine body 1,
Two-stage supercharger 11 for supercharging combustion gas to engine body 1, Intercooler 15 for cooling combustion gas after first-stage compression by two-stage supercharger 11, Two-stage type And a cooler 16 for cooling the combustion gas after the second stage compression by the turbocharger 11. In addition, the marine diesel engine 10 includes air supply pipes 101, 102, and 103 as air supply pipes, and exhaust pipes 111, 112, 113, and 114 as exhaust pipes. Of these pipes, exhaust pipe 1
Reference numerals 12 and 113 denote pipes of the two-stage supercharger 11. In FIG. 1, solid arrows indicate the flow of exhaust gas from the engine main body 1, and broken arrows indicate the flow of combustion gas.

Although not shown, the engine body 1 is a propulsion engine (main engine) that drives and rotates a propeller for propulsion of a ship through a propeller shaft. The engine body 1 is a two-stroke diesel engine such as a uniflow swept exhaust crosshead diesel engine. Specifically, as shown in FIG. 1, the engine body 1 is located below the height direction D11 of the engine body 1 (
And a frame 3 provided on the table 2 and a cylinder jacket 4 provided on the frame 3. The base plate 2, the frame 3 and the cylinder jacket 4 are integrally fastened and fixed by a connecting member such as a plurality of tie bolts (not shown) and nuts (not shown) extending in the height direction D 11. It is done.

The base plate 2 constitutes a crankcase. Although not shown, the base plate 2 is provided with a propeller shaft and a crankshaft for driving and rotating the propulsion propeller. The crankshaft is rotatably supported by bearings. The lower end of a connecting rod (not shown) is rotatably connected to the crankshaft via a crank.

The frame 3 is provided with the connecting rod described above, a piston rod (not shown), and a crosshead (not shown) that rotatably connects the piston rod and the connecting rod. In detail, the lower end of the piston rod and the upper end of the connecting rod are connected to the crosshead. The crosshead is disposed between a pair of guide plates (not shown) fixed to the frame 3 and is slidably supported along the pair of guide plates.

As shown in FIG. 1, a cylinder liner 5 is provided in the cylinder jacket 4 so as to extend from the inside to the top of the cylinder jacket 4, and a cylinder cover 6 is provided on the upper end portion of the cylinder liner 5. There is. These cylinder liners 5 and cylinder covers 6
Thus, the cylinder of the engine body 1 is formed. In the present embodiment, a plurality of (six in FIG. 1) cylinders are formed in the engine body 1. Fuel is supplied to each of the plurality of cylinders from a fuel injection pump (not shown). On the other hand, in the internal space of the cylinder, a piston (not shown) is provided reciprocably along the inner wall of the cylinder. The upper end of the above-described piston rod is attached to the lower end of the piston.

Further, the engine body 1 is provided with a scavenging air trunk 7 and an exhaust manifold 8. As shown in FIG. 1, the scavenging air trunk 7 is provided on the cylinder jacket 4 and is in communication with the combustion chamber in each cylinder via a scavenging port (not shown) of the engine body 1. The scavenging air trunk 7 receives a combustion gas such as compressed air, and sends the received combustion gas into the combustion chamber in each cylinder. As shown in FIG. 1, the exhaust manifold 8 is provided above the cylinder jacket 4 (for example, in the vicinity of the cylinder cover 6), and with the combustion chamber in each cylinder via an exhaust port (not shown) of the engine body 1. It is in communication. The exhaust manifold 8 receives the exhaust gas generated by the combustion of the fuel from the combustion chamber in each cylinder and temporarily stores it, thereby converting the dynamic pressure of the exhaust gas into a static pressure.

The engine body 1 having the configuration as described above reciprocates the piston by burning the fuel together with the combustion gas fed from the scavenging trunk 7 in the combustion chamber in each cylinder. The engine body 1 outputs the propulsion of the ship from the output shaft by converting this reciprocating motion into rotational motion of an output shaft such as a propeller shaft or a crankshaft. At this time, the engine body 1 makes the flow of the intake and exhaust in each cylinder one direction from the lower side to the upper side so as to eliminate the remaining of the exhaust. Specifically, the combustion gas is supplied from the scavenging air trunk 7 to the combustion chamber in each cylinder, and the exhaust gas after combustion is discharged from the combustion chamber in each cylinder to the exhaust manifold 8.

In the present embodiment, the height direction D11 of the engine body 1 is the vertical direction, for example, parallel to the direction of the reciprocation of the piston. The width direction D12 of the engine body 1 is
It is parallel to the output shaft direction D2 shown in FIG. The output shaft direction D2 is the longitudinal direction of the output shaft of the engine body 1. The height direction D11 and the width direction D12 are perpendicular to each other. Further, in the present embodiment, the exhaust gas is a gas discharged to the outside from the engine body 1 through piping and the like.

The two-stage type supercharger 11 is an example of a multi-stage type supercharger capable of compressing combustion gas such as air stepwise and using the exhaust gas from the engine body 1 to the engine body 1 . In the present embodiment, as shown in FIG. 1, the two-stage supercharger 11 includes a high pressure supercharger 12 and a low pressure supercharger 1.
3, a silencer 14, and exhaust pipes 112 and 113.

The high pressure stage turbocharger 12 is a first turbocharger (supercharger) that performs supercharging of the combustion gas using the exhaust gas discharged from the engine body 1. Specifically, as shown in FIG. 1, the high pressure supercharger 12 includes a high pressure turbine 12 a and a high pressure compressor 12 b. Further, although not shown in FIG. 1, the high-pressure stage turbocharger 12 includes a high-pressure stage turbine 12 a and a high-pressure stage compressor 12 b.
And a rotary shaft (a rotary shaft 12c shown in FIG. 2 described later) that connects the two. High pressure turbine 12a
The high-pressure stage compressor 12b is configured to be able to rotate integrally with the rotary shaft as a central axis.

The high pressure stage turbine 12 a is a radial turbine that rotates by receiving the exhaust gas discharged from the engine body 1, and is provided to the engine body 1 in a state of being accommodated in a casing. In the present embodiment, as shown in FIG. 1, an exhaust pipe 111 is connected to the gas inlet side of the casing of the high-pressure stage turbine 12 a. High-pressure stage turbine 12a can receive exhaust gas from engine body 1 in the radial direction of high-pressure stage turbine 12a (hereinafter simply referred to as turbine radial direction) through exhaust pipe 111, and can rotate the energy of this exhaust gas as a power source Is configured as. Also, as shown in FIG. 1, on the gas outlet side of the casing of the high-pressure turbine 12a,
The exhaust pipes 112 and 113 are connected in series in the rotational axis direction D1 of the high pressure stage turbine 12a. As described above, the high pressure turbine 12a is configured to deliver the exhaust gas received in the radial direction of the turbine in the rotational axis direction D1 to flow in the exhaust pipes 112 and 113.

The rotation axis direction D1 is the longitudinal direction of the rotation axis of the high-pressure stage turbine 12a. The turbine radial direction is the radial direction of the radial turbine constituting the high-pressure stage turbine 12a (specifically, the radial direction of the turbine disk). The rotational axis direction D1 and the turbine radial direction are perpendicular to each other.

The high pressure stage compressor 12 b is a compressor that performs the second stage compression of the combustion gas in the two-stage supercharger 11. The high-pressure stage compressor 12b is constituted by an impeller or the like integrally connected with the high-pressure stage turbine 12a via a rotational shaft, and is an engine body in a state housed in a casing so as to be able to rotate integrally with the high-pressure stage turbine 12a. It is provided in 1. Specifically, as shown in FIG. 1, the high pressure stage compressor 12 b is disposed on the opposite side of the low pressure stage turbocharger 13 to the high pressure stage turbine 12 a described above. On the gas inlet side of the casing of the high-pressure stage compressor 12b, an intercooler 1 is provided.
The air supply pipe 102 leading to 5 is connected. Further, an air supply pipe 103 communicating with the cooler 16 is connected to the gas outlet side of the casing of the high-pressure stage compressor 12b.

The low pressure supercharger 13 is a second supercharger (turbocharger) that performs supercharging of the combustion gas using the exhaust gas delivered from the high pressure supercharger 12. Specifically, as shown in FIG.
The low pressure supercharger 13 includes a low pressure turbine 13a and a low pressure compressor 13b. Also,
Although not shown in FIG. 1, the low pressure supercharger 13 includes a low pressure turbine 13 a and a low pressure compressor 13.
A rotating shaft (a rotating shaft 13c shown in FIG. 2 described later) that connects b and b is provided. Low pressure turbine 13
The low pressure compressor 13a is configured to be able to rotate integrally with the rotary shaft as a central axis.

The low pressure stage turbine 13a is an axial flow turbine that receives and rotates the exhaust gas delivered from the high pressure stage turbine 12a (radial turbine), and is provided to the engine body 1 in a state of being accommodated in a casing. Specifically, as shown in FIG. 1, the low pressure turbine 13a is disposed to face the high pressure turbine 12a in the rotational axis direction D1 of the high pressure turbine 12a. That is, the rotational axis direction (longitudinal direction of the rotational axis) of the low pressure stage turbine 13a is the same as the rotational axis direction D1 of the high pressure stage turbine 12a. Exhaust pipes 112 and 113 communicating with the high pressure stage turbine 12a are connected to the gas inlet side of the low pressure stage turbine 13a. The low-pressure stage turbine 13 a discharges the exhaust gas delivered from the high-pressure stage turbine 12 a into the exhaust pipes 112 and 11.
It is configured to be able to receive in the rotational axis direction D1 through 3 and to rotate the energy of this exhaust gas as a power source. Further, as shown in FIG. 1, an exhaust pipe 114 communicating with a chimney or the like (not shown) for exhausting the exhaust gas to the outside is connected to the gas outlet side of the casing of the low pressure stage turbine 13a. The low pressure stage turbine 13a is configured to cause the exhaust gas received in the rotational axis direction D1 to flow in the exhaust pipe 114 as described above.

The low pressure stage compressor 13 b is a compressor that performs the first stage compression of the combustion gas in the two-stage supercharger 11. The low-pressure stage compressor 13b is constituted by an impeller or the like integrally connected with the low-pressure stage turbine 13a via a rotation shaft, and is an engine body in a state housed in the casing so as to be able to rotate integrally with the low-pressure stage turbine 13a. It is provided in 1. Specifically, as shown in FIG. 1, the low pressure stage compressor 13b is disposed on the opposite side of the high pressure stage turbocharger 12 to the low pressure stage turbine 13a described above. On the gas inlet side of the low-pressure stage compressor 13b, a silencer 1 is provided.
4 is provided. The silencer 14 is for reducing noise when inhaling air (fresh air) from the outside. The suction port of the silencer 14 is provided with a filter (not shown) for preventing suction of foreign matter. On the other hand, an air supply pipe 101 communicating with the intercooler 15 is connected to the gas outlet side of the casing of the low-pressure stage compressor 13b.

The exhaust pipe 111 is a pipe that discharges the exhaust gas in the radial direction of the turbine from the engine body 1 toward the high pressure turbine 12a. In the present embodiment, as shown in FIG.
The one end is connected to the exhaust manifold 8 and the other end is connected to the gas inlet of the casing of the high-pressure stage turbine 12a, and the exhaust manifold 8 and the inside of the casing of the high-pressure stage turbine 12a are communicated in the radial direction of the turbine. Such an exhaust pipe 111 exhausts the exhaust gas generated in the engine body 1 from the exhaust manifold 8 toward the high pressure turbine 12 a in the radial direction of the turbine.

The exhaust pipes 112 and 113 are pipes which are disposed between the high pressure turbine 12a and the low pressure turbine 13a, and constitute a flow pipe for circulating the exhaust gas from the high pressure turbine 12a to the low pressure turbine 13a. Specifically, as shown in FIG. 1, the exhaust pipes 112 and 113 are connected in series in the rotational axis direction D1 over the region from the gas outlet side of the high pressure turbine 12a to the gas inlet of the low pressure turbine 13a. It is done. Such exhaust pipes 112 and 113 communicate the internal spaces of the casings of the high-pressure stage turbine 12a and the low-pressure stage turbine 13a facing each other in the rotational axis direction D1 with each other in the rotational axis direction D1, and are delivered from the high-pressure stage turbine 12a The exhaust gas can be circulated in the rotational axis direction D1 toward the low pressure stage turbine 13a.

The intercooler 15 is a cooler for cooling the combustion gas after the first stage compression by the two-stage supercharger 11. Specifically, as shown in FIG.
The low pressure stage compressor 13 b is in communication with the inside of the low pressure stage compressor 13 b, and is in communication with the inside of the high pressure stage compressor 12 b through the air supply pipe 102 and the like. The intercooler 15 is a combustion gas flowing from the low pressure stage compressor 13b through the air supply pipe 101 and flowing from the air supply pipe 102 to the high pressure stage compressor 12b side, that is, the low pressure stage compressor 13b
To cool the high temperature combustion gas compressed by, for example, heat exchange with cooling water or the like.

The cooler 16 is for cooling the combustion gas after the second stage compression by the two-stage supercharger 11. Specifically, as shown in FIG. 1, the cooler 16 communicates with the inside of the casing of the high-pressure stage compressor 12b through the air supply pipe 103, and the scavenging trunk of the engine body 1 through an internal space or the like (not shown). It is configured to be in communication with 7, and provided in the engine main body 1. The cooler 16 flows from the high pressure stage compressor 12 b through the air supply pipe 103 and is used as the scavenging air trunk 7.
The combustion gas flowing to the side, that is, the high-temperature combustion gas further compressed by the high-pressure stage compressor 12b is cooled, for example, by heat exchange with cooling water.

Here, in the marine diesel engine 10 according to the present embodiment, the rotational shafts of the high pressure supercharger 12 and the low pressure supercharger 13 that constitute the two-stage supercharger 11 may be parallel to each other. Are preferably located on the same axis. Furthermore, the high-pressure stage turbocharger 12, the low-pressure stage turbocharger 13, the silencer 14 and the exhaust pipes 112, 11 with respect to the rotational axis direction D1 shown in FIG.
Each central axis of 3 is preferably located on the same axis. Further, in the present embodiment, the rotational axis direction D1 of the high-pressure stage turbocharger 12 and the low-pressure stage turbocharger 13 is the output axis direction D of the engine body 1.
2 (parallel to the width direction D12). That is, the rotating shaft of the high pressure stage turbine 12 a and the rotating shaft of the low pressure stage turbine 13 a are parallel to the output shaft of the engine body 1. Furthermore, the two-stage supercharger 11 is disposed between the exhaust manifold 8 and the intercooler 15 and the cooler 16 in the height direction D11 of the engine body 1. Specifically, as shown in FIG. 1, the high-pressure stage turbocharger 12 and the low-pressure stage turbocharger 13 are disposed below the height direction D11 relative to the exhaust manifold 8. The high-pressure stage compressor 12 b is disposed above the cooler 16, and the low-pressure stage compressor 13 b is disposed above the intercooler 15.

The arrangement configuration of the two-stage turbocharger 11 in the marine diesel engine 10 is the one described above (
Although it is not limited to FIG. 1, the viewpoint of reducing the energy loss of the exhaust gas by shortening the pipe length of the exhaust gas which is a power source of the two-stage turbocharger 11, and miniaturizing the marine diesel engine 10 From the viewpoint, it is preferable to be as described above.

Further, from the viewpoint of improving the supercharging efficiency of the combustion gas by the two-stage supercharger 11, the low-pressure supercharger 13 is a large-sized supercharger compared to the high-pressure supercharger 12. preferable. That is, it is preferable that the low pressure turbine 13a is a large turbine compared to the high pressure turbine 12a, and the low pressure compressor 13b is a large compressor compared to the high pressure compressor 12b.

(Supercharge operation of combustion gas)
Next, with reference to FIG. 1, the supercharging operation of the combustion gas to the engine body 1 in the marine diesel engine 10 according to the present embodiment will be described. Marine diesel engine 10
The two-stage supercharger 11 supercharges the combustion gas such as air to the engine body 1 by operating with the exhaust gas discharged from the engine body 1 as a power source.

Specifically, as shown in FIG. 1, the exhaust gas generated in the combustion chamber in each cylinder of the engine main body 1 is temporarily stored in the exhaust manifold 8, and then the exhaust pipe 111 to the exhaust pipe 111.
Through the high pressure turbine 12a. The high pressure stage turbine 12a receives the exhaust gas from the exhaust pipe 111 in the radial direction of the turbine and rotates it, and delivers the exhaust gas used for this rotation in the rotational axis direction D1. The exhaust gas delivered from the high pressure stage turbine 12a is exhausted from the exhaust pipe 112, 1
The low pressure turbine 13a is supplied to the low pressure turbine 13a. The low pressure turbine 13 a has an exhaust pipe 11.
The exhaust gases from 2 and 113 are received in the rotational axis direction D1 and rotated. The exhaust gas used for this rotation is delivered from the low pressure stage turbine 13a to the exhaust pipe 114, and then exhausted from the chimney (not shown) to the outside through the exhaust pipe 114 or the like.

The rotation of the low pressure stage turbine 13a using the exhaust gas from the high pressure stage turbine 12a as a power source is transmitted to the low pressure stage compressor 13b via the rotary shaft. As a result, the low pressure compressor 13b rotates with the rotation of the low pressure turbine 13a. The low-pressure stage compressor 13b in such a rotated state sucks air (new air) from the outside as a combustion gas through the suction port (suction port provided with a filter) of the silencer 14 or the like, and the suctioned combustion port Compress the gas (first stage compression). The low-pressure stage compressor 13 b pressure-feeds the combustion gas pressurized by the compression action to the intercooler 15 through the air supply pipe 101. The combustion gas compressed by the low pressure stage compressor 13b flows into the intercooler 15 through the air supply pipe 101, is cooled by the intercooler 15, and then the high pressure stage compression from the intercooler 15 through the air supply pipe 102 and the like. Supplied to the machine 12b.

On the other hand, the rotation of the high-pressure stage turbine 12a using the exhaust gas from the engine body 1 as a motive power is transmitted to the high-pressure stage compressor 12b via the rotation shaft. Thus, the high pressure stage compressor 12b rotates with the rotation of the high pressure stage turbine 12a. The high-pressure stage compressor 12b in the rotated state further compresses the combustion gas supplied through the air supply pipe 102, that is, the combustion gas after being compressed by the low-pressure stage compressor 13b described above (second stage compression). The high-pressure stage compressor 12 b pressure-feeds the combustion gas further boosted by the compression action to the cooler 16 through the air supply pipe 103. The combustion gas after compression by the high-pressure stage compressor 12 b is supplied to the air supply pipe 103.
After being cooled by the cooler 16, the air is supplied from the cooler 16 to the scavenging trunk 7 of the engine body 1 through the internal space and the like.

In this way, the necessary amount of combustion gas is supercharged to the engine body 1. The supercharged combustion gas is supplied (scavenged) from the scavenging air trunk 7 to the combustion chamber in each cylinder of the engine body 1 and burned together with the fuel.

(Configuration of turbine)
Next, the arrangement configuration of the high-pressure stage turbine 12a and the low-pressure stage turbine 13a in the present embodiment will be described in detail. FIG. 2 is a schematic view showing an example of the arrangement configuration of the high-pressure stage turbine and the low-pressure stage turbine according to the embodiment of the present invention. In FIG. 2, solid arrows indicate the flow of exhaust gas that is a power source of turbine rotation.

As shown in FIG. 2, the high-pressure stage turbine 12 a is a radial turbine that receives and rotates exhaust gas in the radial direction of the turbine, and is accommodated in a casing 12 d. An exhaust pipe 111 is connected to a gas inlet portion of the casing 12 d. A flow passage is formed in the casing 12d from the gas inlet side through the high pressure turbine 12a to the gas outlet side. High-pressure stage turbine 12a receives exhaust gas from both sides in the radial direction of the turbine through flow passages in exhaust pipe 111 and casing 12d. The high-pressure stage turbine 12a sequentially delivers the exhaust gas used for the rotation in the rotational axis direction D1 while rotating about the rotation shaft 12c as a rotation center by the pressure of the exhaust gas from the radial direction of the turbine. Although not particularly shown in FIG. 2, the high pressure stage turbine 12 a is integrally connected to the high pressure stage compressor 12 b (see FIG. 1) via a rotating shaft 12 c.

Further, as shown in FIG. 2, the low pressure stage turbine 13a is an axial flow turbine that receives and rotates the exhaust gas in the rotational axis direction D1, and is accommodated in a casing (not shown). The low pressure stage turbine 13a receives the exhaust gas delivered from the high pressure stage turbine 12a in the rotational axis direction D1, and rotates about the rotational shaft 13c by the pressure of the exhaust gas. Although not particularly illustrated in FIG. 2, the low pressure stage turbine 13 a is integrally connected to the low pressure stage compressor 13 b (see FIG. 1) via a rotation shaft 13 c.

The high pressure turbine 12a and the low pressure turbine 13a are disposed to face each other in the rotational axis direction D1, as shown in FIG. At this time, the high-pressure stage turbine 12a and the low-pressure stage turbine 13a have their respective turbine blade sides opposed to the rotational axis direction D1. Such opposing arrangement makes it possible to shorten the flow path until exhaust gas delivered from the high pressure stage turbine 12a in the rotational axis direction D1 is supplied to the axial flow turbine blades of the low pressure stage turbine 13a as short as possible. Further, from the viewpoint of simply shortening the flow pipe forming the flow path, the rotary shaft 12c of the high pressure turbine 12a and the rotary shaft 13c of the low pressure turbine 13a are preferably positioned on the same axis, Furthermore, the rotary shaft 12 of the high pressure turbine 12a
Preferably, the central axis C1 of c and the central axis C2 of the rotary shaft 13c of the low pressure stage turbine 13a coincide on the same axis.

In the present embodiment, the flow pipe forming the flow path of the exhaust gas from the high pressure stage turbine 12a to the low pressure stage turbine 13a described above is constituted by the exhaust pipes 112 and 113 as shown in FIG. One exhaust pipe 112 is a telescopic pipe that can expand and contract in the rotation axis direction D1. One end of the exhaust pipe 112 is connected to the gas outlet of the casing 12d of the high-pressure stage turbine 12a, and the other end is connected to the other exhaust pipe 113 to communicate the casing 12d and the exhaust pipe 113 in the rotational axis direction D1. . The other exhaust pipe 113 is a pipe which becomes a part of the gas inlet side of the casing of the low pressure stage turbine 13a. One end of the exhaust pipe 113 is the exhaust pipe 112 described above.
The other end is connected to the turbine nozzle 13d of the casing of the low pressure stage turbine 13a, and the exhaust pipe 112 and the turbine nozzle 13d communicate with each other in the rotational axis direction D1. Further, as shown in FIG. 2, inside the exhaust pipe 113, a flow path branched to both sides in the turbine radial direction of the low pressure turbine 13a from the high pressure turbine 12a to the low pressure turbine 13a is formed. There is.

The exhaust pipes 112 and 113 are disposed, for example, between the high pressure turbine 12a and the low pressure turbine 13a so as to extend in the rotational axis direction D1, and circulate the exhaust gas from the high pressure turbine 12a to the low pressure turbine 13a. . Specifically, as shown in FIG.
12 circulates the exhaust gas delivered from the high pressure stage turbine 12a in the rotational axis direction D1 from the gas outlet of the casing 12d of the high pressure stage turbine 12a toward the other exhaust pipe 113 in the rotational axis direction D1. The other exhaust pipe 113 circulates the exhaust gas delivered from the exhaust pipe 112 in the rotational axis direction D1 in the rotational axis direction D1 while diverting the exhaust gas toward the turbine nozzle 13d of the casing of the low pressure stage turbine 13a. In addition, the exhaust pipe 112, which is a telescopic pipe, absorbs the thermal stress that the exhaust pipes 112, 113 receive due to the circulation of the high temperature exhaust gas by the expansion and contraction in the rotation axis direction D1. Thus, the exhaust pipe 112 prevents deformation and breakage of the exhaust pipes 112 and 113 due to thermal stress.

  The exhaust gas supplied from the turbine nozzle 13 d to the low pressure turbine 13 a through the exhaust pipes 112 and 113 rotates the low pressure turbine 13 a and then flows into the exhaust pipe 114 in the casing of the low pressure turbine 13 a. Thereafter, the exhaust gas is discharged from the chimney to the outside through the exhaust pipe 114 and the like.

As described above, in the marine diesel engine 10 according to the embodiment of the present invention, the exhaust gas discharged from the engine body 1 of the high pressure turbine 12a of the high pressure turbocharger 12 (the first turbocharger) is The low-pressure turbine 13a of the low-pressure turbocharger 13 (second turbocharger) is an axial-flow turbine that receives and rotates the exhaust gas delivered from the high-pressure turbine 12a. High-pressure stage turbocharger 12 and low-pressure stage turbocharger 13 are arranged such that high-pressure stage turbine 12a and low-pressure stage turbine 13a face rotational axis direction D1, and between high-pressure stage turbine 12a and low-pressure stage turbine 13a. (Eg, exhaust pipe 112)
, 113), the exhaust gas flows from the high pressure stage turbine 12a to the low pressure stage turbine 13a.

Therefore, the gas outlet portion of the exhaust gas delivered from the high pressure stage turbine 12a in the rotational axis direction D1 and the gas inlet portion of the low pressure stage turbine 13a receiving the exhaust gas in the rotational axial direction D1 are as far as possible in the rotational axis direction D1. It can be arranged in close proximity. Thus, the high pressure turbine 12
The length of the flow pipe (flow path length) for flowing the exhaust gas from a to the low pressure stage turbine 13a can be made as short as possible. As a result, it is possible to reduce the heat radiation and pressure loss associated with the flow of the exhaust gas through the flow pipe, so it is possible to reduce the energy loss of the exhaust gas that is the power source of the turbine of each turbocharger.

Furthermore, since the high-pressure stage turbocharger 12, the low-pressure stage turbocharger 13, and the above-mentioned flow pipe can be arranged in close proximity in the rotational axis direction D1, the occupied area necessary for the arrangement of the turbochargers with respect to the engine body 1 can be reduced. It can be reduced. As a result, for example, the size of the marine diesel engine 10
It can be miniaturized as compared with the conventional diesel engine disclosed in Patent Documents 1 and 2 described above.

Further, in the marine diesel engine 10 according to the embodiment of the present invention, the exhaust pipe 111 for discharging the exhaust gas in the radial direction of the turbine from the engine body 1 toward the high pressure turbine 12a is provided. Therefore, from the engine body 1 (for example, the exhaust manifold 8) to the high pressure turbine 1
The flow path of the exhaust gas to 2a can be made as short as possible. As a result, shortening of the exhaust pipe 111 forming the flow path can be promoted.
Reduce the heat dissipation and pressure loss of the exhaust gas discharged to the high-pressure stage
Energy loss of the exhaust gas, which is a power source of the high pressure stage turbine 12a, can be reduced as much as possible.

Further, in the marine diesel engine 10 according to the embodiment of the present invention, the high pressure turbine 12 is used.
The high-pressure stage turbocharger 12 and the low-pressure stage turbocharger 13 are disposed such that the rotation shaft of a and the rotation shaft of the low-pressure stage turbine 13a are co-axially positioned. Therefore, the exhaust gas flow pipe between the high-pressure stage turbine 12a and the low-pressure stage turbine 13a, which are disposed to face each other in the rotational axis direction D1, can be simply and short. As a result, the flow path length of the exhaust gas from the high pressure stage turbine 12a to the low pressure stage turbine 13a can be easily shortened, so that the reduction of the energy loss of the exhaust gas can be promoted.

Further, in the marine diesel engine 10 according to the embodiment of the present invention, the high pressure turbine 12 is used.
The high-pressure stage turbocharger 12 and the low-pressure stage turbocharger 13 are provided in the engine body 1 such that the rotation axis of the low-pressure stage turbine 13 a is parallel to the output axis of the engine body 1. ing. Therefore, it is necessary to arrange the turbochargers with respect to the engine main body 1 while shortening the flow path length of the exhaust gas serving as a power source of the high pressure stage turbine 12a and the low pressure stage turbine 13a to realize reduction of energy loss of the exhaust gas. Reduce the occupied area as much as possible, and
It is possible to suppress the deviation of the load applied to the joint between the and each supercharger. As a result, compared to the conventional diesel engines disclosed in Patent Documents 1 and 2 described above, the size reduction of the marine diesel engine 10 can be promoted, and the joint between the engine body 1 and each supercharger is excessive. The respective superchargers can be disposed on the engine body 1 in a well-balanced manner so as not to be biased load.

Specifically, in the conventional diesel engine disclosed in Patent Document 1, the high-pressure stage turbocharger and the low-pressure stage turbocharger are mutually perpendicular (ie, lateral) to the rotational axis of the turbine.
Are arranged on one side of the engine body together with related devices such as a cooler. In this case, at the junction between each of these turbochargers and related devices (hereinafter abbreviated as “devices such as turbochargers” as appropriate) and the engine body, the load biased to one side of the engine body is excessive. May be loaded. Therefore, in order to ensure the connection between the devices such as the turbochargers and the engine body, it is necessary to firmly reinforce these connection portions. Due to this, there arises a problem that the time and cost required for arranging the devices such as the turbochargers with respect to the engine main body increase.

Further, in the conventional diesel engine disclosed in Patent Document 2, the high-pressure stage turbocharger and the low-pressure stage turbocharger are separately disposed on both end faces in the width direction of the engine body together with related devices such as a cooler. There is. In this case, since the devices such as the turbochargers protrude from both end faces in the width direction of the engine body, the width dimension of the diesel engine (for example, the length of the engine body in the output shaft direction) increases. There is a problem that downsizing of the diesel engine becomes difficult. After all, there is a risk that it will be necessary to expand the space in the engine room where diesel engines will be installed, and as a result, there is a risk that important space other than the engine room in the ship must be reduced. .

In the marine diesel engine 10 according to the embodiment of the present invention as compared to these conventional diesel engines, as described above, downsizing can be promoted, and since the turbochargers can be arranged in a well-balanced manner in the engine main body 1, Can solve all the problems of diesel engines.

Further, in the marine diesel engine 10 according to the embodiment of the present invention, the low pressure supercharger 13 is disposed above the intercooler 15 and the high pressure supercharger 12 is disposed above the cooler 16.
For this reason, the compressor of the low-pressure stage turbocharger 13 (low-pressure stage compressor 13b) does not inhibit shortening of the pipe (exhaust pipe 111) for circulating the exhaust gas from the engine body 1 to the high-pressure stage turbine 12a.
Piping (air supply pipe 101) for allowing the compressed combustion gas to flow from the intermediate cooler 15 to the intercooler 15, and the combustion gas after compression from the compressor (high-pressure stage compressor 12b) of the high-pressure stage turbocharger 12 to the cooler 16 Both the length of the pipe (air supply pipe 103) for circulating the As a result, the piping between the high pressure supercharger 12, the low pressure supercharger 13, the intercooler 15 and the cooler 16 can be simply formed short, and as a result, the size of the marine diesel engine 10 can be reduced. Miniaturization can be realized easily.

Further, in the marine diesel engine 10 according to the embodiment of the present invention, the high-pressure stage turbocharger 12 and the low-pressure stage turbocharger 13 are compared with the exhaust manifold 8 of the engine main body 1 in the height direction D11.
Is located below the Therefore, while shortening the exhaust pipe 111 communicating the exhaust manifold 8 with the inside of the casing of the high pressure stage turbine 12 a, the high pressure stage turbocharger 12 and the low pressure stage turbocharger 13 can be separated from the upper end of the engine body 1. It can be arranged so as not to go out. As a result, since the height dimension (the length in the height direction D11) of the marine diesel engine 10 can be shortened, downsizing of the marine diesel engine 10 can be further promoted.

Further, in the marine diesel engine 10 according to the embodiment of the present invention, the high pressure turbine 12 is used.
The flow pipe which distributes the exhaust gas from a to the low pressure stage turbine 13a is provided with a telescopic pipe (exhaust pipe 112) which can extend and contract in the rotational axis direction D1 of these turbines. Therefore, the expansion and contraction due to the heat received from the high temperature exhaust gas can be absorbed by the exhaust pipe 112 which is the expansion and contraction pipe. Thereby, the deformation | transformation and the failure | damage by the thermal stress of the said flow pipe can be prevented, As a result, lifetime improvement of the said flow pipe can be achieved.

Further, in the marine diesel engine 10 according to the embodiment of the present invention, the low-pressure stage turbocharger 13 is a large-sized turbocharger compared to the high-pressure stage turbocharger 12. For this reason, the compression ratio at the time of compressing the combustion gas in stages can be easily optimized, whereby the supercharging efficiency of the combustion gas can be enhanced.

In the embodiment described above, two superchargers (high-pressure stage turbocharger 12 and low-pressure stage turbocharger 1)
Although the case where the two-stage-type supercharger 11 which has 3) was applied to the engine main body 1 was illustrated, this invention is not limited to this. For example, a multistage turbocharger may be applied to the engine body 1 in which the combustion gas is compressed stepwise by a plurality of (two or more) turbochargers. In this case, a plurality of high-pressure stage turbochargers 12 may be provided among the high-pressure stage turbochargers 12 and the low-pressure stage turbochargers 13 constituting the multistage turbocharger, and a plurality of low-pressure stage turbochargers 13 may be provided. It may be provided or may be a combination of these.

In the embodiment described above, the exhaust pipe 112, which is a telescopic tube, and the low pressure turbine 13 are examples of a flow pipe for circulating the exhaust gas from the high pressure turbine 12a to the low pressure turbine 13a.
Although the flow pipe constituted by connecting with the exhaust pipe 113 which becomes the gas inlet side end of the casing of a is illustrated, the present invention is not limited to this. For example, the flow pipe may not include an expansion pipe, and in this case, the gas inlet of the exhaust pipe 113 may be connected to the gas outlet of the casing 12d of the high-pressure stage turbine 12a. In addition, the flow pipe includes two exhaust pipes 112.
, 113, and may be configured by a single exhaust pipe, or may be configured by a plurality (two or more) of exhaust pipes.

Furthermore, although the piping by the side of the high pressure stage turbine 12a in the above-mentioned flow pipe was made into the expansion and contraction pipe in the embodiment mentioned above, the present invention is not limited to this. In the present invention, the pipe (for example, the exhaust pipe 113) on the low pressure stage turbine 13a side of the flow pipe may be a telescopic pipe.

Further, in the above-described embodiment, the gas inlet portion of the exhaust pipe 111 for circulating the exhaust gas from the engine body 1 to the high-pressure stage turbine 12a is connected to the exhaust manifold 8, but the present invention is limited thereto It is not a thing. For example, the gas inlet portion of the exhaust pipe 111 may be connected to each cylinder of the engine body 1 without the exhaust manifold 8. In this case, the engine body 1 may not have the exhaust manifold 8.

In the above-described embodiment, air (fresh air) sucked from the outside is used as the combustion gas, but the present invention is not limited to this. For example, an EGR system is further provided to recirculate a part of the exhaust gas from the engine body 1 to the engine body 1, and this EGR
A mixed gas of recirculation gas from the system and air from the outside may be used as the combustion gas.

Further, the present invention is not limited by the above-described embodiment, and the present invention also includes those configured by appropriately combining the above-described respective constituent elements. In addition, other embodiments, examples, operation techniques and the like made by those skilled in the art based on the above-described embodiments are all included in the scope of the present invention.

Reference Signs List 1 engine body 2 base plate 3 structure 4 cylinder jacket 5 cylinder liner 6 cylinder cover 7 scavenging air trunk 8 exhaust manifold 10 marine diesel engine 11 two-stage turbocharger 12 high-pressure stage turbocharger 12a high-pressure stage turbine 12b high-pressure stage compressor 12c , 13c Rotating shaft 12d Casing 13 Low pressure stage turbocharger 13a Low pressure stage turbine 13b Low pressure stage compressor 13d Turbine nozzle 14 Silencer 15 Intercooler 16 Cooler 101, 102, 103 Supply pipe 111, 112, 113, 114 Exhaust pipe C1 , C2 Central axis D1 Rotational axis direction D2 Output axis direction D11 Height direction D12 Width direction

Claims (8)

An engine body that burns fuel and outputs propulsion power of the ship from the output shaft,
A first turbocharger having a radial turbine rotating in response to exhaust gas discharged from the engine body;
A second turbocharger having an axial flow turbine disposed so as to face the radial turbine in the direction of the rotational axis of the radial turbine, and receiving and rotating the exhaust gas delivered from the radial turbine;
A flow pipe disposed between the radial turbine and the axial flow turbine for circulating the exhaust gas from the radial turbine to the axial flow turbine;
Marine diesel engine characterized by having. The marine diesel engine according to claim 1, further comprising an exhaust pipe for discharging the exhaust gas in the radial direction of the radial turbine from the engine body toward the radial turbine. The marine diesel engine according to claim 1 or 2, wherein a rotation shaft of the radial turbine and a rotation shaft of the axial flow turbine are located on the same shaft. The marine diesel according to any one of claims 1 to 3, wherein a rotation shaft of the radial turbine and a rotation shaft of the axial flow turbine are parallel to the output shaft of the engine body. engine. A first cooler for cooling the combustion gas compressed by the compressor of the second turbocharger;
A second cooler for cooling the combustion gas further compressed by the compressor of the first turbocharger;
Equipped with
The second supercharger is disposed above the first cooler, and the first supercharger is the second supercharger.
The marine diesel engine according to any one of claims 1 to 4, wherein the marine diesel engine is disposed above the cooler. The engine body comprises an exhaust manifold,
The first supercharger and the second supercharger are disposed on the lower side in the height direction of the engine body compared to the exhaust manifold. Marine diesel engine as described in one or more. The flow pipe may include an expansion and contraction pipe extendable and contractible in the rotation axis direction.
The marine diesel engine according to any one of ~ 6. The marine diesel engine according to any one of claims 1 to 7, wherein the second supercharger is a large supercharger as compared with the first supercharger.

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