JP2015098795A - Diesel engine for use as ship main engine and exhaust valve cooling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diesel engine for use as a ship main engine, capable of improving reliability and durability by cooling an exhaust valve.SOLUTION: A diesel engine for use as a ship main engine, including an exhaust valve opened by using a driving force obtained by compressing a hydraulic oil and transmitted from a lower valve mechanism to an upper valve mechanism 20, comprises: a refrigerant circulation channel 30 formed in a valve element of the exhaust valve for introducing part of the hydraulic oil; and an exhaust channel provided to penetrate a casing 25 of the upper valve mechanism 20. When opening and closing the exhaust valve, an outlet opening of the refrigerant circulation channel 30 communicating with an inlet opening of the exhaust channel to generate a flow in part of the hydraulic oil.

Description

  The present invention relates to a ship main engine diesel engine and a method for cooling an exhaust valve of a ship main engine diesel engine.

In recent years, marine diesel engines have a tendency that the wall surface temperature of the combustion chamber increases as the output increases. In particular, exhaust valves that are generally non-cooled are heated at the bottom surface in contact with high-temperature combustion gas, and exhaust valve wear due to wear has been reported. Such exhaust valve wear becomes a serious problem for large-diameter engines (piston diameter of 60 cm or more) that are difficult to cool because the exhaust valve is large.
In a conventional marine diesel engine, wear is reduced by changing the material of an exhaust valve or the like.

  In Patent Document 1 below, for example, a plurality of gaseous refrigerants or at least partially transitionable to a gaseous state is provided inside a valve arranged in one gas passage of a two-cycle large diesel engine. A cooling mechanism for feeding a refrigerant composed of these components is disclosed.

Special table 2013-522513 gazette

As described above, in recent diesel engines for ship main engines, exhaust valve wear has become a problem as the output increases. However, in order to improve the reliability and durability of the marine main engine diesel engine, it is desired to cool the exhaust valve efficiently.
The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a diesel engine for a ship main engine and an exhaust valve that can improve reliability and durability by cooling the exhaust valve. It is to provide a cooling method.

In order to solve the above problems, the present invention employs the following means.
The diesel engine for a ship main engine according to the present invention is the diesel engine for a ship main engine provided with an exhaust valve that is compressed using hydraulic oil and is opened using a driving force transmitted from the lower valve mechanism to the upper valve mechanism. A refrigerant circulation passage formed inside the valve body of the exhaust valve for introducing a part of the hydraulic oil, and an oil discharge passage provided through a housing of the upper valve mechanism, During the opening / closing operation of the valve, the outlet opening of the refrigerant circulation passage and the inlet opening of the drain oil passage communicate with each other to cause a part of the hydraulic oil to flow.

  According to such a marine main engine diesel engine, the refrigerant circulation passage formed inside the valve body of the exhaust valve and introducing a part of the hydraulic oil and the casing of the upper valve mechanism are provided. An exhaust oil passage, and when the exhaust valve is opened and closed, the outlet opening of the refrigerant circulation passage and the inlet opening of the exhaust oil passage communicate with each other to cause a flow of part of the hydraulic oil. The exhaust valve can be reliably cooled by effectively utilizing part of the hydraulic oil used in the valve operating mechanism.

  In the above invention, it is preferable to provide a flow rate control unit in the drain oil flow path, whereby the flow rate of hydraulic oil used for cooling can be appropriately controlled. In addition, as a suitable flow control part, the servo valve etc. which can optimize a flow-path cross-sectional area according to load other than an orifice can be illustrated.

  In the above invention, the piston stroke of the lower valve mechanism is preferably set by adding a value corresponding to the amount of hydraulic oil discharged to a value required for the exhaust valve opening / closing operation. By cooling the exhaust valve, it is possible to compensate for the amount of oil that flows out to the oil discharge passage. That is, the piston stroke of the lower valve mechanism may be set to a value that is longer by the amount of hydraulic oil supplied corresponding to the amount of exhaust oil than when the exhaust valve is not cooled by hydraulic oil.

  In the above invention, the position at which the outlet opening of the refrigerant circulation flow path and the inlet opening of the oil discharge flow path communicate with each other is such that the exhaust valve lift L equals the seat area and the minimum passage area. It is preferable to set it so that it is (L1) or more (L> L1), and this makes it possible to cool the exhaust valve using a part of the hydraulic oil without affecting the engine performance.

  The exhaust valve cooling method according to the present invention compresses hydraulic oil and cools the exhaust valve of a diesel engine for a ship main engine having an exhaust valve that is opened using a driving force transmitted from the lower valve mechanism to the upper valve mechanism. In the method, a part of the working oil is introduced into the valve body as a cooling medium when the exhaust valve is opened and closed, and is circulated.

  According to such an exhaust valve cooling method, since a part of the hydraulic oil is introduced into the valve body and circulated as a cooling medium during the opening / closing operation of the exhaust valve, a part of the hydraulic oil used for the valve operating mechanism of the exhaust valve The exhaust valve can be surely cooled by effectively utilizing.

  According to the above-described present invention, a part of the hydraulic oil used for the valve operating mechanism of the exhaust valve can be effectively used and reliably cooled, and the reliability and durability of the exhaust valve can be improved. Further, since a part of the hydraulic oil is effectively used, the structure can be easily changed as compared with the case where a new refrigerant and a refrigerant supply system are provided.

The figure which shows one Embodiment of the diesel engine for ship main engines which concerns on this invention, and an exhaust valve cooling method, and shows the branch part of the refrigerant | coolant circulation flow path which guide | induces some hydraulic fluids introduced into the upper valve mechanism to the inside of a valve body It is principal part sectional drawing. It is principal part sectional drawing which shows the refrigerant | coolant circulation flow path provided in the valve body of an exhaust valve. It is a principal part sectional view showing a communication (flow) state of a refrigerant circulation channel and an oil discharge channel accompanying opening and closing operation of an exhaust valve, and (a) is a state in which hydraulic fluid is not flowing because both channels do not communicate with each other. (B) is a state in which both flow paths communicate with each other and the hydraulic fluid flows. It is sectional drawing which shows the piston stroke of a lower valve mechanism, (a) is a conventional structure, (b) is a structure in the case of utilizing a part of hydraulic fluid for exhaust valve cooling. It is explanatory drawing which shows an exhaust valve lift, a seat part area, and a seat minimum area. It is explanatory drawing of a preferable setting about the communication position of a refrigerant | coolant circulation flow path and an oil discharge flow path, (a) shows the relationship of the exhaust valve lift with respect to a crank angle, (b) has shown the relationship of the opening area with respect to a crank angle. It is explanatory drawing of the setting which is unpreferable about the communication position of a refrigerant | coolant circulation flow path and an oil discharge flow path, (a) shows the relationship of the exhaust valve lift with respect to a crank angle, (b) has shown the relationship of the opening area with respect to a crank angle. . 1 is a schematic configuration diagram of a diesel engine for a ship main engine equipped with an exhaust valve that is opened by using a driving force that is compressed by hydraulic oil and transmitted from a lower valve mechanism to an upper valve mechanism, and is electronically controlled as a lower valve mechanism The structural example of the exhaust valve which employ | adopted the type | formula is shown. 1 is a schematic configuration diagram of a diesel engine for a ship main engine provided with an exhaust valve that is opened by using a driving force that is compressed by hydraulic oil and transmitted from a lower valve mechanism to an upper valve mechanism, and is a cam type as a lower valve mechanism 2 shows an example of the configuration of an exhaust valve that employs.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a diesel engine for a ship main engine and an exhaust valve cooling method according to the present invention will be described based on the drawings.
The marine engine diesel engine of the present embodiment includes an exhaust valve structure that is opened by using a driving force that is compressed from hydraulic oil and transmitted from the lower valve mechanism to the upper valve mechanism.

In the exhaust valve structure shown in FIG. 8, an exhaust passage 3 is provided in communication with the upper portion of the combustion chamber 2 formed in the cylinder 1, and the open / close valve mechanism 4 is opened and closed so as to open and close the exhaust passage 3. An exhaust valve 5 is provided.
The opening / closing valve mechanism 4 shown in FIG. 8 includes a lower valve mechanism 10 and an upper valve mechanism 20. The opening / closing valve mechanism 4 is closed by being pushed up by the air spring 21 of the upper valve mechanism 20 using the driving force transmitted by supplying the hydraulic oil compressed by the lower valve mechanism 10 to the upper valve mechanism 20. The exhaust valve 5 in the closed state is opened by being pushed down by the pressure of the hydraulic oil. In addition, the code | symbol 6 in a figure is the hydraulic fluid flow path which connects between the lower valve mechanism 10 and the upper valve mechanism 20.

The lower valve mechanism 10 shown in FIG. 8 is an electronic control type that operates the electromagnetic valve unit 11 including the main valves 11a and 11b and pushes up the piston 13 in the hydraulic cylinder 12, but is not limited thereto. Absent. For example, a cam type in which the piston 13 is pushed up by the cam 15 as the lower valve mechanism 10A, such as the opening / closing valve mechanism 4A shown in FIG. In FIG. 9, reference numeral 16 in the drawing denotes a spring that biases the piston 13 downward.
The electronically controlled open / close valve mechanism 4 and the cam-type open / close valve mechanism 4A have the same configuration and operation on the upper valve mechanism 20 described later, regardless of which mechanism is employed.

The upper valve mechanism 20 is an opening / closing operation support member that supports the shaft portion 5a to move in the vertical direction so that the exhaust valve 5 can move in the vertical direction to open and close the exhaust passage 3. In addition to the air spring 21 described above, the upper valve mechanism 20 includes a piston 23 installed in a cylinder portion 22 that receives the hydraulic oil supplied from the lower valve mechanism 10. The piston 23 is attached to the upper end portion of the shaft portion 5a and operates integrally.
The shaft portion 5a is supported by the bearing portion 24 so as to be vertically slidable between the air spring 21 and the umbrella portion 5b.

  As described above, the diesel engine for a ship main engine provided with the exhaust valve 5 that is opened by using the driving force transmitted from the lower valve mechanism 10, 10 </ b> A to the upper valve mechanism 20 by compressing the hydraulic oil is described in this embodiment. 1 to 3, the refrigerant circulation passage 30 formed inside the valve body of the exhaust valve 5 to introduce a part of the hydraulic oil and the housing 25 of the upper valve mechanism 20 are penetrated. And an oil discharge passage 40 provided. The refrigerant circulation flow path 30 and the oil discharge flow path 40 communicate with the outlet opening 31 of the refrigerant circulation flow path 30 and the inlet opening 41 of the oil discharge flow path 40 when the exhaust valve 5 is opened and closed. A flow is generated in part of the hydraulic oil introduced into the flow path 30.

The refrigerant circulation passage 30 opens to the piston 23 so that the hydraulic oil inlet 32 communicates with the inside of the cylinder portion 22, and reaches the umbrella portion 5b through the inside of the piston 23 and the shaft portion 5a. The refrigerant circulation passage 30 provided inside the umbrella portion 5b passes through a position as close to the bottom surface as possible over the entire circumference, and again reaches the outlet opening 31 through the shaft portion 5a. That is, with respect to the umbrella portion 5b of the exhaust valve 5 that easily rises in temperature, it is desirable to provide the refrigerant circulation passage 30 that passes through the entire circumference as close as possible to the surface.
Further, in the state where the exhaust valve 5 is closed, the outlet opening 31 opens into the air spring 21, but in order to prevent hydraulic oil from flowing out from the outlet opening 31, the ring wall 27 is fixed to the upper surface of the flange 26. It is provided. As a result, the outlet opening 31 is closed by the wall surface from the bearing portion 24 to the ring wall 27 except for the position communicating with the inlet opening 41 of the oil drainage flow path 40 in the opening / closing operation range of the exhaust valve 5. Become.

The oil discharge passage 40 is provided through the casing 25 of the upper valve mechanism 20, and the inlet opening 41 thereof is located at a position where the exhaust valve 5 is opened and communicates with the inlet opening 31 of the refrigerant circulation passage 30. is there. The other end of the oil drain passage 40 is connected to a hydraulic oil tank (not shown).
Further, an orifice 42 is provided at an appropriate position of the oil discharge passage 40 as a flow rate control unit for controlling the flow rate of the hydraulic oil, for example, in the vicinity of the outer wall surface of the housing 25. The orifice 42 prevents the amount of hydraulic oil outflow from becoming excessive. Instead of the orifice 42, a servo valve or the like that can optimize the cross-sectional area of the flow path according to the load may be employed.

According to the above-described embodiment, when the exhaust valve 5 is fully closed, no hydraulic oil is supplied from the lower valve mechanism 10, and therefore the exhaust valve 5 receives an upward bias from the air spring 21 and receives the seat. It is in close contact with the surface. At this time, the working oil in the refrigerant circulation flow path 30 remains in the flow path without flowing because the working oil is not supplied and the outlet opening 31 is blocked.
However, when the lower valve mechanism 10 operates, a hydraulic oil flow (arrow F) flows through the hydraulic oil flow path 6 and flows into the cylinder portion 22 of the upper valve mechanism 20. For this reason, the pressure of the hydraulic oil acts on the piston 23 to generate a force that pushes down the shaft portion 5a. By overcoming the bias of the air spring, the piston 23 and the exhaust valve 5 are pushed down. As a result, the exhaust passage 3 is opened.

  Further, part of the hydraulic oil that has flowed into the cylinder portion 23 flows into the refrigerant circulation passage 30 from the inlet 32. Then, as shown in FIG. 3B, when the positions of the outlet opening 31 and the inlet opening 41 coincide or substantially coincide with each other and are in communication with each other, the hydraulic oil in the refrigerant circulation passage 30 is shown by an arrow f in the figure. The exhaust valve 5 is cooled as shown in FIG. At this time, the hydraulic oil that has cooled the exhaust valve 5 flows out from the exhaust oil flow path 40 to the orifice 42 and flows out, and new hydraulic oil flows in from the inlet 32 so as to replenish this outflow. For this reason, the hydraulic oil in the refrigerant circulation flow path 30 flows through the flow path only at the timing when the exhaust valve 5 is activated and communicates with the hydraulic oil discharge flow path 40, and the hydraulic oil is cooled by the low temperature hydraulic oil. The exhaust valve 5 is cooled efficiently and reliably.

  By the way, the piston stroke of the lower valve mechanisms 10 and 10A, that is, the piston stroke given to the piston 13 in the hydraulic cylinder 12 is such that a part of the hydraulic oil (arrow f) is drained by the cooling of the exhaust valve 5. In order to compensate for the amount of oil drained to 40, it is desirable to add a value corresponding to the amount of hydraulic oil drainage to the value required for the exhaust valve opening / closing operation.

More specifically, as shown in FIG. 4B, the piston stroke (H <H) is added to the conventional piston stroke H shown in FIG. + ΔH). That is, the piston stroke of the present embodiment set in the lower valve mechanism 10 is longer than the case where the exhaust valve is not cooled (conventional structure) by the amount of hydraulic oil supplied corresponding to the amount of oil discharged. You only have to set it.
4A and 4B show the electronically controlled open / close valve mechanism 4, the same applies to the cam-type open / close valve mechanism 4A.

  Further, the position where the outlet opening 31 of the refrigerant circulation passage 30 and the inlet opening 41 of the oil discharge passage 40 communicate with each other (the communication position of the cooling oil passage) is part of the hydraulic oil without affecting the engine performance. It is desirable to enable the exhaust valve cooling using the. For this reason, as shown in FIG. 5, the exhaust valve lift L determined by the fully closed position indicated by the solid line and the open position of the exhaust valve 5 indicated by the imaginary line is formed between the exhaust valve 5 and the seat portion. The exhaust valve lift L is set to L1 or more (L> L1), where L1 is an exhaust valve lift amount in which the seat area Sa is equal to the minimum passage area Sb set in the exhaust flow path 3.

FIG. 6 is an explanatory diagram of preferable settings for the communication positions of the refrigerant circulation passage 30 and the oil discharge passage 40. FIG. 6A shows the relationship of the exhaust valve lift with respect to the crank angle, and FIG. 6B shows the relationship of the opening area (seat portion area Sa) with respect to the crank angle.
The exhaust valve lift and the opening area of the exhaust valve 5 are increased as the crank angle is advanced, and are closed after maintaining a constant value within a predetermined crank angle range. In addition, the solid line display in a figure is a case where exhaust valve cooling is not performed, and a broken line display is a part which changes with exhaust valve cooling.

On the other hand, the effective area used for exhaust is the area shaded in FIG. 6B, and the sheet area (opening area) Sa is the area of the area smaller than the minimum passage area Sb.
Then, as shown in FIG. 6A, the exhaust valve lift L having a crank angle corresponding to the minimum passage area Sb is the exhaust valve lift amount L1 of “seat portion area Sa = passage minimum area Sb”.
Therefore, if the exhaust valve lift L is set to a region where the exhaust valve lift L is larger than the exhaust valve lift L1 corresponding to the minimum passage area Sb, the reduction in the area caused by the exhaust valve cooling is used for exhaust. Therefore, the exhaust valve can be cooled without affecting the engine performance.

  However, as shown in FIGS. 7A and 7B, when communication of the cooling oil passage is performed in a region within an effective area used for exhaust, a part of the hydraulic oil is used for cooling to open the valve. Since the amount that can be used for the operation is reduced, when the exhaust valve 5 is opened and the exhaust gas in the combustion chamber 2 is discharged, the exhaust valve lift and the opening area are delayed. That is, the exhaust valve lift and the opening area indicated by the broken line move in a direction in which the crank angle is advanced from the solid line display within the effective area used for the exhaust, so that the hatching portion shown in FIG. As a result, the engine performance is deteriorated due to poor gas exchange. In other words, the communication position of the cooling oil passage is set to a region where the exhaust valve lift L is larger than the exhaust valve lift L1 corresponding to the passage minimum area Sb, which corresponds to the hatched portion in FIG. This area is outside the effective area used for exhaust, and as a result, deterioration of engine performance due to poor gas exchange can be prevented.

  Further, the above-described diesel engine for the main engine of the ship according to the above-described embodiment compresses the hydraulic oil and exhausts the exhaust valve 5 that is opened using the driving force transmitted from the lower valve mechanisms 10 and 10A to the upper valve mechanism 20. As a valve cooling method, it is possible to introduce and circulate a part of the hydraulic oil used in the opening / closing valve mechanism 4 as a cooling medium during the opening / closing operation of the exhaust valve 5, and as a result, the exhaust valve 5. The exhaust valve can be reliably cooled by effectively utilizing part of the hydraulic oil used in the valve mechanism.

As described above, according to the above-described embodiment, a part of the hydraulic oil used in the valve operating mechanism of the exhaust valve 5 can be effectively used and reliably cooled, and the reliability and durability of the exhaust valve are improved. Can be made. Further, since a part of the hydraulic oil is effectively used, it is easy to change the structure of the marine main engine diesel engine as compared with the case where a new refrigerant and a refrigerant supply system are provided.
Note that the present invention is not limited to the above-described embodiment, and can be appropriately modified within a range not departing from the gist of the invention, for example, applicable to a diesel engine other than a similar marine main engine.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Combustion chamber 3 Exhaust flow path 4, 4A Opening-closing valve mechanism 5 Exhaust valve 5a Shaft part 5b Umbrella part 6 Actuation flow path 10, 10A Lower valve mechanism 11 Electromagnetic valve unit 12 Hydraulic cylinder 13 Piston 15 Cam 16 Spring 20 Upper valve mechanism 21 Air spring 22 Cylinder portion 23 Piston 24 Bearing portion 25 Housing 26 Flange 27 Ring wall 30 Refrigerant circulation passage 31 Outlet opening 32 Inlet 40 Oil drainage passage 41 Inlet opening 42 Orifice (flow rate control portion)

Claims (5)

In a diesel engine for a ship main engine equipped with an exhaust valve that is opened using a driving force that compresses hydraulic oil and is transmitted from the lower valve mechanism to the upper valve mechanism,
A refrigerant circulation passage formed inside the valve body of the exhaust valve for introducing a part of the hydraulic oil, and an oil discharge passage provided through a housing of the upper valve mechanism,
A diesel engine for a ship main engine characterized in that when the exhaust valve is opened and closed, an outlet opening of the refrigerant circulation passage and an inlet opening of the oil discharge passage communicate with each other to cause a part of the hydraulic oil to flow. engine.   The ship engine main engine diesel engine according to claim 1, wherein a flow rate control unit is provided in the oil discharge passage.   3. The piston stroke of the lower valve mechanism is set by adding a value corresponding to the amount of hydraulic oil discharged to a value required for an exhaust valve opening / closing operation. Diesel engine for main ship.   The position where the outlet opening of the refrigerant circulation channel and the inlet opening of the oil discharge channel communicate with each other is such that the exhaust valve lift L is equal to or greater than the exhaust valve lift amount (L1) in which the seat area is equal to the minimum passage area ( It is set so that it may become L> L1), The diesel engine for ship main engines of any one of Claim 1 to 3 characterized by the above-mentioned. In the exhaust valve cooling method for a diesel engine for a ship main engine provided with an exhaust valve that is opened using a driving force that compresses hydraulic oil and is transmitted from the lower valve mechanism to the upper valve mechanism,
An exhaust valve cooling method for a diesel engine for a ship main engine, wherein a part of the hydraulic oil is introduced into the inside of the valve body as a cooling medium during the opening / closing operation of the exhaust valve.

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