JP2020159328A - Marine diesel engine, cylinder liner forming engine and component of cylinder liner, and maintenance method of engine - Google Patents

Abstract

To enable replacement of a piston ring to be performed without involving piston removal work in a marine diesel engine.SOLUTION: A cylinder liner includes: a cylinder linear upper part (31) having a top part (31a) which is located at the outer side of a cylinder frame when the cylinder frame is installed and a base part (31c) extending from a through hole of the cylinder frame to a scavenging chamber; and a cylinder liner lower part (32) which is detachably connected to a lower end of the base part (31c).SELECTED DRAWING: Figure 3

Description

The present invention relates to a marine diesel engine, the engine itself, a cylinder liner and its parts constituting the engine, and a maintenance method for the engine.

In a marine diesel engine, a work called piston removal is required as one of the maintenance. As an example of this piston removing operation, the following non-patent document 1 discloses the following procedure.

1. 1. After extracting the cooling water, lubricating oil, etc. of the main engine (referring to the diesel engine for ships), the various pipe systems connected to the upper stage of the main engine are removed, and the cylinder cover, which is the superstructure, is removed.

2. 2. Remove the lower connection of the piston and pull the piston out of the cylinder.

3. 3. Cleans, measures, and records (photographs) piston rings and cylinder liners on sliding parts.

4. After servicing the piston, cylinder liner, penetrating part of the piston rod, etc., attach the piston ring to the extracted piston, apply cylinder oil, and store it in the cylinder.

5. Restore the connection at the bottom of the piston rod and the cylinder cover.

6. After the connection pipe system above the main engine is restored, check for leaks through cooling water, lubricating oil, etc.

7. Perform a test run, check the situation, and finish the work.

Japan Ship Engineers Association "Introducing piston removal work as inboard work." [Online] [Search on February 22, 2019], Internet <http://www.marine-engineer.or. jp / images / piston_shokai.pdf>

According to Non-Patent Document 1, the piston removal work is one of the large-scale and important work that requires a large number of people and sufficient preparation, and it usually takes about 8 to 10 hours with a total of about 6 engine departments. It is said that. For the piston removal work of the DF engine (two-dimensional fuel engine), it is necessary to disassemble the piping for fuel gas, etc., so the work time and work load are larger than in the case of the conventional marine diesel engine. Become. Further, it is considered that the description in Non-Patent Document 1 is premised on a machine-controlled engine, but for the piston removal work of the electronically controlled engine, in addition to the removal work of the various pipe systems, electronic devices such as sensor cables are used. Since it is necessary to remove the equipment, the work time and work load are larger than those of the machine-controlled engine.

In conventional marine diesel engines, maintenance related to the inside of the cylinder liner cannot be performed without piston removal work, and it can be performed without piston removal work, but its workability is poor. There is something.

The former includes maintenance that requires attachment / detachment of the piston ring, such as replacement of the piston ring.

Further, examples of the latter include measurement of the amount of wear of the cylinder liner and partial inspection / cleaning of the piston crown / piston rod. These can be carried out by inserting a jig or the like into the inside of the cylinder liner through the scavenging holes formed in the cylinder liner. However, since the scavenging holes are generally relatively small, the workability of maintenance through the scavenging holes deteriorates.

Therefore, the present invention can expand the range of maintenance that can be performed without the piston removal work, or can improve the workability of the maintenance that can be performed without the piston removal work, and its parts. , And the purpose of providing maintenance methods for marine diesel engines.

In order to solve the above problems, the cylinder liner according to one aspect of the present invention is a cylinder liner of a marine diesel engine, and when installed in a cylinder frame forming an air scavenging chamber inside, the cylinder cover is attached. Detachable connection to the upper part of the cylinder liner having a top located outside the cylinder frame for mounting and a base extending from a through hole formed in the cylinder frame to the scavenging chamber and a lower end of the base. The lower part of the cylinder liner is provided.

In a configuration in which the cylinder liner cannot be divided into upper and lower parts and is integrally formed, maintenance work on the inside of the cylinder liner is impossible without removing the piston, or workability is poor.

On the other hand, in the above configuration, by removing the lower part of the cylinder liner from the upper part of the cylinder liner without removing the piston, maintenance work related to the inside of the cylinder liner, particularly near the connection position between the upper part of the cylinder liner and the lower part of the cylinder liner can be performed. Partially possible, or its workability is improved.

A marine diesel engine according to one aspect of the present invention includes the cylinder liner, the cylinder frame, a piston crown that reciprocates in the cylinder liner, and a piston rod connected to the piston crown.

The cylinder liner component of the marine diesel engine according to one aspect of the present invention comprises the lower part of the cylinder liner for forming the cylinder liner.

The maintenance method for a marine diesel engine according to one aspect of the present invention relates to a cylinder liner installed in a cylinder frame forming an air scavenging chamber inside, and extends from a through hole formed in the cylinder frame to the air scavenging chamber. A step of removing the lower part of the cylinder liner detachably connected to the lower end of the base part from the base part, a step of performing maintenance work on a part that can be worked or became easier to work by removing the lower part of the cylinder liner, and a step of performing maintenance work on the base part. The step of attaching the lower part of the cylinder liner is included.

According to one aspect of the present invention, the range of maintenance that can be performed without the piston removal work can be expanded, or the workability of the maintenance that can be performed without the piston removal work can be improved.

It is a partial sectional view of the diesel engine for a ship which concerns on one Embodiment of this invention. It is a front view which shows the state which the cylinder liner is installed in the cylinder frame in the marine diesel engine of FIG. It is a front view which shows the whole of the cylinder liner of FIG. It is a perspective view of the upper part of the cylinder liner which constitutes the cylinder liner of FIG. It is a perspective view of the lower part of the cylinder liner which constitutes the cylinder liner of FIG. It is a front view which shows the state of the cylinder liner during the replacement work of a piston ring.

A partial cross-sectional view of FIG. 1 shows a marine diesel engine 1 according to an embodiment of the present invention. In the scope and specification of the claims of the present application, the concepts of "top" / "bottom" and "top" / "bottom" shall be determined based on the reciprocating direction of the piston of the marine diesel engine 1. The top dead center side and bottom dead center side of the piston are defined as "top", "bottom", "top", and "bottom", respectively.

[Overall configuration of marine diesel engine]
The marine diesel engine 1 includes a crankcase 10, a cylinder frame 20, a cylinder liner 30, a cylinder cover 40, an exhaust collecting pipe 50, a supercharger 60, a scavenging trunk 70, and a fuel injection / exhaust valve drive. The device 80 is provided.

The crankcase 10 has a crankshaft 11, a crosshead 12, and a connecting rod 13 connecting them arranged inside the crankcase 10. Further, a part of the piston rod 15 is inserted into the inside of the crankcase 10 from above. The piston rod 15 has a piston crown 14 at the upper tip and reciprocates up and down. This motion is transmitted to the connecting rod 13 via the crosshead 12, and is converted into a rotary motion by the connecting rod 13 and the crankshaft 11.

The cylinder frame 20 is installed on the top of the crankcase 10. A through hole is formed in the bottom of the cylinder frame 20, and a stuffing box 21 is provided in the through hole. The stuffing box 21 penetrates the piston rod 15 while maintaining airtightness between the inside of the crankcase 10 and the inside of the cylinder frame 20.

A part of the cylinder liner 30 is inserted into the inside of the cylinder frame 20 through a through hole formed in the top of the cylinder frame 20, and the other part protrudes above the cylinder frame 20. The cylinder liner 30 houses a part of the piston crown 14 and the piston rod 15 inside.

The cylinder cover 40 is arranged at the top of the cylinder liner 30 and maintains airtightness between the space above the piston crown 14 inside the cylinder liner 30 and the outside of the cylinder liner 30. An exhaust port 41 is formed in the cylinder cover, and an exhaust valve 42 is provided in the exhaust port 41.

For example, six cylinder liners 30 and six cylinder covers 40 are arranged along the vertical direction of the paper in FIG. 1, forming a 6-cylinder engine. The crosshead 12, the connecting rod 13, the piston crown 14, the piston rod 15, the stuffing box 21, and the like are also provided in the same number as the cylinder liner 30 and the cylinder cover 40.

The exhaust collecting pipe 50 is a pipe that communicates with the exhaust port 41 of each cylinder cover 40 and the supercharger 60, respectively, and is for sending the gas exhausted from each exhaust port 41 to the supercharger 60. ..

The supercharger 60 uses the flow of exhaust gas sent through the exhaust collecting pipe 50 to compress the outside air and supply it to the scavenging trunk 70.

The scavenging trunk 70 is for supplying the compressed air supplied from the supercharger 60 to the scavenging chamber 22 formed inside the cylinder frame 20. The cylinder frame 20 is formed with a scavenging port 23 (see FIG. 2) at a position on the side wall of the cylinder frame 20 facing each cylinder liner 30. A large number of scavenging holes 32e (see FIG. 3) are formed along the peripheral wall of the cylinder liner 30. Compressed air is introduced into the cylinder liner 30 through the scavenging port 23 and the scavenging hole 32e.

Further, the scavenging trunk 70 is provided with an inspection door 71. By opening the inspection door 71, the operator can invade the inside of the scavenging trunk 70 and further reach the scavenging chamber 22 through the scavenging port 23.

The fuel injection / exhaust valve drive device 80 is arranged on the side of the cylinder liner 30 at the top of the cylinder frame 20. The fuel injection / exhaust valve drive device 80 supplies fuel to the cylinder cover 40 and performs hydraulic control for hydraulically driving the exhaust valve 42.

[Operation of marine diesel engine]
The marine diesel engine 1 operates as follows.

In the state where the piston crown 14 is located at the bottom dead center, the top of the piston crown 14 is located below the scavenging hole 32e of the cylinder liner 30, and the exhaust valve 42 is opened. As a result, scavenging is performed. That is, the compressed air supplied from the scavenging trunk 70 to the scavenging chamber 22 and introduced into the cylinder liner 30 through the scavenging hole 32e expels the combustion gas in the previous cycle from the exhaust port 41 and fills the cylinder liner 30. To do.

When the piston crown 14 starts to rise from the bottom dead center, the piston crown 14 itself moves above the scavenging hole 32e, so that the inside of the cylinder liner 30 and the scavenging chamber 22 are airtight and the exhaust valve 42 is closed. ..

When the piston crown 14 further rises and reaches near top dead center, the compressed air is compressed and heated above the ignition point of the fuel. In that state, the fuel is injected into the cylinder liner 30 by the fuel injection / exhaust valve drive device 80, and the fuel is self-ignited.

The piston crown 14 turns downward after passing through top dead center, and is driven downward by the expansion of the combustion gas generated by the ignition. After that, the exhaust valve 42 is opened, and the piston crown 14 returns to bottom dead center again.

The vertical reciprocating motion of the piston crown 14 generated by repeating the above is converted into a rotary motion as described above, and becomes the output of the marine diesel engine 1.

[Installation and structure of cylinder liner]
The front view of FIG. 2 shows a state in which the cylinder liner 30 is installed on the cylinder frame 20, and the front view of FIG. 3 shows the entire cylinder liner 30. 2 and 3 are views of the cylinder liner 30 and the like viewed from the scavenging trunk side in FIG. Note that FIG. 1 shows a partially simplified configuration of the cylinder liner 30 and the like.

The cylinder liner 30 includes a cylinder liner upper portion 31, a cylinder liner lower portion (cylinder liner component) 32, and a connection ring 33 and a detent 34 for connecting them and preventing them from rotating with each other.

The cylinder liner upper portion 31 includes a top portion 31a on which the cylinder cover 40 is mounted, a protruding portion 31b protruding from the cylinder frame 20, and a base portion 31c extending from a through hole formed in the cylinder frame 20 into the scavenging chamber 22. Have.

The cylinder liner lower portion 32 is detachably connected to the lower end of the base portion 31c of the cylinder liner upper portion 31. The cylinder liner lower portion 32 is mounted on the cylinder liner upper portion 31 to form one cylinder liner 30. The connection position between the upper portion 31 of the cylinder liner and the lower portion 32 of the cylinder liner is a position on the top dead center side of the top of the piston crown 14 when the piston crown 14 is located at the bottom dead center.

In the lower portion 32 of the cylinder liner, a large number of the above-mentioned sweep holes 32e are formed on the peripheral surface thereof along the circumferential direction. Further, the cylinder liner lower portion 32 has two members 32a and 32b divided into two by a plane including the central axis of the cylinder liner 30, and eight stopping pieces 32c that detachably combine them. Although four stop pieces 32c are shown in FIGS. 2 and 3, the remaining four stop pieces are arranged on opposite sides of these so as to be symmetrical with each other.

As shown in the perspective views of FIGS. 4 and 5, the connection method between the cylinder liner upper portion 31 and the cylinder liner lower portion 32 is a bayonet type using a connection ring 33.

As shown in FIG. 4, the connecting ring 33 is fitted into the lowermost outer periphery of the base portion 31c of the cylinder liner upper portion 31 and screwed. The substantially upper half of the connecting ring 33 overlaps the outer circumference of the base portion 31c, but the substantially lower half protrudes below the lower end of the base portion 31c. Four inner claws 33a projecting inward are provided at equal intervals on the inner circumference of the protruding portion. In addition, two notches 33b are formed in the protruding portion.

As shown in FIG. 5, four outer claws 32d protruding outward are formed on the outer periphery of the uppermost portion of the lower portion 32 of the cylinder liner.

When connecting the lower part 32 of the cylinder liner to the upper part 31 of the cylinder liner, first, the lower part 32 of the cylinder liner is fitted into the connection ring 33 so that the outer claw 32d of the lower part 32 of the cylinder liner enters the gap of the inner claw 33a of the connection ring 33. Cylinder. Then, by rotating the lower part 32 of the cylinder liner with respect to the connecting ring 33, the outer claw 32d of the lower part 32 of the cylinder liner and the inner claw 33a of the connecting ring 33 are engaged with each other up and down. In this state, two detents 34 are fitted into the two notches 33b of the connection ring 33, and these detents 34 are screwed to the lower portion 32 of the cylinder liner. As a result, the lower portion 32 of the cylinder liner is positioned in the vertical direction and the rotational direction with respect to the upper portion 31 of the cylinder liner, and these are integrated.

[Cylinder liner related jig]
Three tightening tools 35 surrounding the lower portion 32 of the cylinder liner are attached. As will be described later, the tightening tool 35 is a jig used when disassembling and assembling the lower portion 32 of the cylinder liner, and can be removed when operating the marine diesel engine 1.

Two elevating mechanisms (stands) 24 are installed below the lower portion 32 of the cylinder liner. The elevating mechanism 24 is also a jig for elevating and lowering the cylinder liner lower portion 32 when attaching and detaching the cylinder liner lower portion 32, and can be removed when operating the marine diesel engine 1.

The elevating mechanism 24 includes a base 24a installed on the bottom surface of the cylinder frame 20 (not shown in FIG. 3), a jack bolt 24b screwed into the base 24a, and a top plate attached to the top of the jack bolt 24b. It has 24c. Further, the two elevating mechanisms 24 correspond to the two members 32a and 32b constituting the cylinder liner lower portion 32, respectively.

[Piston ring replacement work]
In the following, assuming the cylinder liner 30 having the above-described structure, the replacement work of the piston ring 14a (see FIG. 6) attached to the piston crown 14 will be described as an example of the maintenance work of the marine diesel engine 1.

The front view of FIG. 6 shows the state of the cylinder liner 30 during the replacement work of the piston ring 14a. The replacement work of the piston ring 14a is performed according to the following procedure. In addition, the following 2. Subsequent work is performed by an operator who has entered the scavenging chamber 22.

1. 1. By driving the inspection motor and rotating the crankshaft 11, the piston crown 14 to be replaced is moved to the vicinity of the bottom dead center.

2. 2. Three tightening tools 35 are attached around the lower portion 32 of the cylinder liner, and the two members 32a and 32b constituting the lower portion 32 of the cylinder liner are tightened with a predetermined force (see FIG. 3). This is to prevent them from being inadvertently pushed by the repulsive force of the piston ring 14a when the two members 32a and 32b are disassembled.

3. An elevating mechanism 24 is installed below each of the two members 32a and 32b, and the jack bolt 24b is rotated to support the members 32a and 32b. This is to prevent the members 32a and 32b from falling at once.

4. Remove the two detents 34 and rotate the cylinder liner lower portion 32 by 45 ° so that the outer claw 32d of the cylinder liner lower portion 32 dodges the inner claw 33a of the connecting ring 33 and is located in the gap between them.

5. The lower part 32 of the cylinder liner is separated from the upper part 31 of the cylinder liner by rotating the jack bolt 24b of each elevating mechanism 24 and lowering the lower part 32 of the cylinder liner.

6.8 The eight stop pieces 32c are removed, and the three tightening tools 35 are also removed, the members 32a and 32b are moved horizontally apart from each other, and the piston crown 14 is exposed from the gap between them.

7. An expander is inserted into the gap, and the piston ring 14a is removed from the piston crown 14 (see FIG. 6).

8. The piston ring 14a is replaced with a new one, and the cylinder liner 30 is assembled by generally following the above procedure in reverse.

[Frequency of piston ring replacement work / piston removal work]
In a marine diesel engine, the life of the cylinder liner and piston crown is 60,000 hours (referring to the operating time of the marine diesel engine 1. The same shall apply hereinafter), and the overhaul interval of these is 30,000 hours, which is half of the life. On the other hand, the life of the piston ring is 16000 hours.

In the case of a conventional marine diesel engine equipped with an inseparable cylinder liner, it is necessary to remove the piston (open the piston) even when replacing the piston ring. Therefore, it was necessary to perform the piston removal work every 16000 hours. In this case, the number of times the piston removal work is performed before the life of the cylinder liner or piston crown (60,000 hours) is determined.
60,000 hours / 16,000 hours = 3.75 times.

On the other hand, in the marine diesel engine 1 of the present embodiment, the replacement work of the piston ring 14a can be carried out without the piston removal work. Therefore, the number of times the piston removal work is performed in the marine diesel engine 1 is
60,000 hours / 30,000 hours = 2 times. Therefore, in calculation, the piston removal work for 1.75 times can be omitted as compared with the above 3.75 times.

However, considering the actual state of maintenance, it is realistic to perform the piston removal work including the replacement of the piston ring at the time of the inspection at the dock, which is carried out once around 30,000 hours. Taking this into consideration, in the case of a conventional marine diesel engine equipped with an inseparable cylinder liner, the piston removal work is performed at 16000 hours, 32000 hours, 48000 hours, and 60,000 hours, respectively. On the other hand, in the marine diesel engine 1 of the present embodiment, the piston removal work is performed in 32,000 hours and 60,000 hours, but the piston ring 14a is replaced in 16,000 hours and 48,000 hours without the piston removal work. It can be performed. Then, in the marine diesel engine 1 of the present embodiment, the piston removal work for two times is performed by the life of the cylinder liner and the piston crown (60,000 hours) as compared with the conventional marine diesel engine provided with the inseparable cylinder liner. It can be omitted.

[Modification example]
The structure of the marine diesel engine 1 described above can be modified as follows.

The marine diesel engine 1 is an in-line type in which cylinder liners 30 and the like are arranged in series, but may be a V type or the like arranged in a V shape.

The cylinder liner 30 can be divided into two vertically, but may be divided into three or more, and at least one connection position may be located in the cylinder frame 20. In the case of three divisions or more, the portion above the connection position may be regarded as the cylinder liner upper portion 31 and the portion below the connection position may be regarded as the cylinder liner lower portion 32 with reference to an arbitrary connection position located in the cylinder frame 20.

In order to enable the replacement of the piston ring 14a by disconnecting the connection position, the connection position is higher than the top of the piston crown 14 when the piston crown 14 is located at the bottom dead center. It must be on the dead center side. However, even when the connection position is located below this, the amount of wear of the cylinder liner 30 can be measured inside the cylinder liner 30, particularly near the connection position, and a part of the piston crown 14 or the piston can be measured. It has a certain effect that inspection and cleaning of a part of the rod 15 can be carried out with good workability.

In the cylinder liner 30, the boundary between the cylinder liner upper portion 31 and the cylinder liner lower portion 32 is along a plane perpendicular to the longitudinal direction of the cylinder liner 30, but is along a plane inclined with respect to the longitudinal direction. May be good. Further, the boundary between the cylinder liner upper portion 31 and the cylinder liner lower portion 32 does not have to be in a plane, and may be, for example, a corrugated shape. By inclining or corrugating the boundary, it is possible to suppress the mechanical influence of the piston ring 14a from a slight gap in the boundary when the piston ring 14a passes through the boundary portion.

The connection method between the upper portion 31 of the cylinder liner and the lower portion 32 of the cylinder liner is not limited to the bayonet type, and may be any detachable connection method.

The cylinder liner lower portion 32 can be divided into two members 32a and 32b, but the cylinder liner lower portion 32 may be divided into three or more members. As the number of divisions increases, the number of stop pieces 32c required increases, and the work of attaching and detaching them increases. However, since the weight of each divided member of the cylinder liner lower portion 32 becomes lighter, the workability of handling them becomes easier. Get better.

Further, the lower portion 32 of the cylinder liner does not necessarily have to be divided by a plane including the central axis of the cylinder liner 30, and is in a direction different from the longitudinal direction of the cylinder liner 30 (preferably a direction perpendicular to the longitudinal direction). It suffices if they can be separated from each other.

Further, if sufficient space for lowering the cylinder liner lower portion 32 to expose the piston ring 14a can be secured below the cylinder liner lower portion 32, the cylinder liner lower portion 32 does not need to be divisible.

The two members 32a and 32b of the lower portion 32 of the cylinder liner are fixed by the fixing pieces 32c on both the front and rear surfaces, but one of them may be replaced with a hinge.

[Summary]
As described above, when the cylinder liner according to the embodiment of the present invention is installed in the cylinder frame 20 forming the scavenging chamber 22 inside, it is placed on the outside of the cylinder frame 20 in order to mount the cylinder cover 40. A cylinder liner upper portion 31 having a base portion 31c extending from a position top portion 31a and a through hole formed in the cylinder frame 20 into the scavenging chamber 22, and a cylinder liner lower portion 32 detachably connected to the lower end portion of the base portion 31c. And have.

In a configuration in which the cylinder liner cannot be divided into upper and lower parts and is integrally formed, maintenance work on the inside of the cylinder liner is impossible without removing the piston, or workability is poor.

On the other hand, in the above configuration, by removing the cylinder liner lower portion 32 from the cylinder liner upper portion 31 without performing the piston removing operation, the inside of the cylinder liner, particularly near the connection position between the cylinder liner upper portion 31 and the cylinder liner lower portion 32. Some maintenance work can be done, or the workability is improved.

The cylinder liner lower portion 32 is formed by detachably combining a plurality of members 32a and 32b that can be separated from each other in a direction different from the longitudinal direction of the cylinder liner 30.

In the above configuration, the cylinder liner lower portion 32 is removed from the cylinder liner upper portion 31, and the plurality of members 32a and 32b constituting the cylinder liner lower portion 32 are moved in a direction different from the longitudinal direction of the cylinder liner 30, typically. By separating and separating from each other in the longitudinal direction and the vertical report, it becomes easy to secure a work space below the base 31c.

Further, the marine diesel engine 1 according to the embodiment of the present invention is connected to the cylinder liner 30, the cylinder frame 20, the piston crown 14 reciprocating in the cylinder liner 30, and the piston crown 14. It includes a piston rod 15.

The connection position between the upper portion 31 of the cylinder liner and the lower portion 32 of the cylinder liner is a position on the upper dead center side of the top of the piston crown 14 when the piston crown 14 is located at the lower dead center.

In the above configuration, the piston crown 14 can be exposed by positioning the piston crown 14 near the bottom dead center and removing the cylinder liner lower portion 32 from the cylinder liner upper portion 31. As a result, maintenance work for the piston crown 14 such as replacement of the piston ring 14a and maintenance work for the portion on the top dead center side inside the cylinder liner 30 can be performed.

Further, the maintenance method of the marine diesel engine according to the embodiment of the present invention includes a step of removing the cylinder liner lower portion 32 detachably connected from the base portion 31c to the lower end of the base portion 31c and a cylinder liner with respect to the cylinder liner 30. It includes a step of performing maintenance work on a portion that can be worked or becomes easy to work by removing the lower portion 32, and a step of attaching the cylinder liner lower portion 32 to the base portion 31c.

In the above method, some maintenance work can be performed without the piston removal work, or the workability thereof is improved.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims, and the present invention also relates to an embodiment obtained by appropriately combining the technical means disclosed in the embodiment. It is included in the technical scope of the invention.

1 Diesel engine for ships 10 Crank case 11 Crank shaft 12 Cross head 13 Connecting rod 14 Piston crown 14a Piston ring 15 Piston rod 20 Cylinder frame 21 Staffing box 22 Sweeping chamber 23 Sweeping port 24 Lifting mechanism 30 Cylinder liner 31 Cylinder liner upper part 31a Top 31b Projection 31c Base 32 Cylinder liner lower part 32a Cylinder liner lower part member 32b Cylinder liner lower part member 32c Stop piece 32e Sweep hole 40 Cylinder cover 50 Exhaust collecting pipe 60 Supercharger 70 Sweeping trunk 80 Exhaust valve drive apparatus

Claims (10)

In the cylinder liner of marine diesel engines
When installed in a cylinder frame that forms a scavenging chamber inside, it extends from the top located outside the cylinder frame to mount the cylinder cover and the through hole formed in the cylinder frame to the scavenging chamber. With the upper part of the cylinder liner having the base to be
The lower part of the cylinder liner, which is detachably connected to the lower end of the base,
Cylinder liner with. The lower portion of the cylinder liner is formed by detachably combining a plurality of members that can be separated from each other in a direction different from the longitudinal direction of the cylinder liner.
The cylinder liner of claim 1. The connection method between the upper part of the cylinder liner and the lower part of the cylinder liner is a bayonet type.
The cylinder liner of claim 1 or 2. A sweep hole is formed in the peripheral surface of the lower part of the cylinder liner.
The cylinder liner according to any one of claims 1 to 3. The cylinder liner according to any one of claims 1 to 4 and
With the cylinder frame
A piston crown that reciprocates in the cylinder liner and
With the piston rod connected to the piston crown,
Marine diesel engine equipped with. The connection position between the upper part of the cylinder liner and the lower part of the cylinder liner is a position on the top dead center side of the top of the piston crown when the piston crown is located at the bottom dead center.
The marine diesel engine of claim 5. Cylinder liner parts for marine diesel engines
The lower part of the cylinder liner for forming the cylinder liner according to any one of claims 1 to 4.
Cylinder liner parts. In the maintenance method of marine diesel engine
Regarding the cylinder liner installed in the cylinder frame forming the scavenging chamber inside, a cylinder detachably connected to the lower end of the base portion from a base extending from a through hole formed in the cylinder frame to the scavenging chamber. The process of removing the lower part of the liner and
The process of performing maintenance work on the parts that can be worked or became easier to work by removing the lower part of the cylinder liner,
The process of attaching the lower part of the cylinder liner to the base and
Maintenance methods for marine diesel engines, including. An elevating mechanism for raising and lowering the lower part of the cylinder liner when attaching and detaching the lower part of the cylinder liner is used.
The maintenance method for a marine diesel engine according to claim 8. A step of moving the piston crown so that the top of the piston crown reciprocating in the cylinder liner is on the bottom dead center side of the connection position between the base and the lower portion of the cylinder liner is further included.
The method for maintaining a marine diesel engine according to claim 8 or 9.

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