WO2015072175A1

WO2015072175A1 - Exhaust valve operating mechanism, diesel engine, and method for cooling exhaust valve of exhaust valve operating mechanism

Info

Publication number: WO2015072175A1
Application number: PCT/JP2014/067799
Authority: WO
Inventors: 村田　聡
Original assignee: 三菱重工業株式会社
Priority date: 2013-11-18
Filing date: 2014-07-03
Publication date: 2015-05-21
Also published as: JP2015098795A; CN105683512A; CN105683512B; JP6091008B2; KR20160067937A; KR101760648B1

Abstract

Provided are: an exhaust valve operating mechanism in which an exhaust valve is cooled to improve reliability and durability; a diesel engine; and a method for cooling the exhaust valve of an exhaust valve operating mechanism. An exhaust valve operating mechanism comprises an exhaust valve which is opened by drive force obtained by compressing hydraulic oil and transmitted from a lower valve operating mechanism to an upper valve operating mechanism (20). The exhaust valve operating mechanism further comprises: a refrigerant circulation passage (30) which is formed within the valve body of the exhaust valve and into which a part of the hydraulic oil is introduced; and an oil discharge passage which is provided extending through the housing (25) of the upper valve operating mechanism (20). During the opening and closing operation of the exhaust valve, the outlet opening of the refrigerant circulation passage (30) and the inlet opening of the oil discharge passage connect to each other to cause a part of the hydraulic oil to flow.

Description

Exhaust valve valve mechanism, diesel engine and exhaust valve cooling method for exhaust valve mechanism

The present invention relates to an exhaust valve operating mechanism, a diesel engine, and an exhaust valve cooling method for the exhaust valve operating mechanism.

In recent years, the wall temperature of the combustion chamber of the marine diesel engine tends to rise with the improvement of the output. In particular, exhaust valves that are generally non-cooling type have been reported to suffer from wear and tear because they have their temperature rise in contact with the high temperature combustion gas at the bottom. Such exhaust valve wear and tear becomes a serious problem for large-diameter engines (piston diameter of 60 cm or more) whose exhaust valves are large and difficult to cool.
In conventional marine diesel engines, it has been attempted to reduce wear and tear by changing the material of exhaust valves and the like.

Further, in Patent Document 1 listed below, for example, a gaseous refrigerant or a plurality of transitionable at least partially into a gaseous state can be made inside a valve disposed in one gas passage of a two-stroke large-sized diesel engine A cooling mechanism is disclosed that feeds a refrigerant consisting of the following components.

Japanese Patent Publication No. 2012-522513

As described above, in recent diesel engines for ship main engines, the exhaust valve wear has become a problem with the increase in power. However, efficient cooling of the exhaust valve is also desired to improve the reliability and durability of the ship main engine diesel engine.
The present invention has been made to solve the above-mentioned problems, and an object thereof is an exhaust valve operating mechanism capable of cooling an exhaust valve to improve reliability and durability, a diesel engine, and It is an object of the present invention to provide an exhaust valve cooling method of an exhaust valve operating mechanism.

The present invention adopts the following means in order to solve the above-mentioned problems.
The exhaust valve actuating mechanism according to the present invention is an exhaust valve actuating mechanism including an exhaust valve which is opened using a driving force transmitted from a lower valve operating mechanism to an upper valve operating mechanism by compressing hydraulic oil. A refrigerant circulation channel formed inside a valve body of an exhaust valve and introducing a part of the hydraulic oil, and an oil discharge channel provided penetrating through a case of the upper valve mechanism, the exhaust At the time of the opening and closing operation of the valve, the outlet opening of the refrigerant circulation channel and the inlet opening of the oil discharge channel communicate with each other to generate a flow in a part of the hydraulic oil.

According to such an exhaust valve operating mechanism, the refrigerant circulation flow path formed inside the valve body of the exhaust valve and introducing a part of the hydraulic oil and provided through the casing of the upper valve operating mechanism Since the outlet opening of the refrigerant circulation channel is communicated with the inlet opening of the oil discharge channel at the time of opening and closing operation of the exhaust valve, and the flow is generated in a part of the hydraulic oil The exhaust valve can be reliably cooled by effectively utilizing a portion of the hydraulic oil used in the valve mechanism.

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

In the above invention, it is preferable that the piston stroke of the lower valve operating mechanism is set by adding a value corresponding to the amount of oil discharge of the hydraulic fluid to a value necessary for the opening and closing operation of the exhaust valve. As a result, by cooling the exhaust valve, it is possible to compensate for the amount of oil discharged from the part of the hydraulic oil to the oil discharge channel. That is, the piston stroke of the lower valve operating mechanism may be set to a value that is longer by the amount of hydraulic oil supplied equivalent to the amount of hydraulic oil as compared with the case where the exhaust valve cooling with hydraulic oil is not performed.

In the above invention, the exhaust valve lift amount at which the exhaust valve lift L equalizes the seat portion area and the passage minimum area at the position where the outlet opening of the refrigerant circulation flow channel communicates with the inlet opening of the oil discharge channel. It is preferable to set (L1) or more (L ≧ L1), and this enables exhaust valve cooling using a part of hydraulic fluid without affecting engine performance.

A diesel engine according to the present invention includes the above-described exhaust valve operating mechanism.

The exhaust valve cooling method of the exhaust valve actuating mechanism according to the present invention comprises an exhaust valve having an exhaust valve which is opened using a driving force transmitted from a lower valve operating mechanism to an upper valve operating mechanism by compressing hydraulic oil. The exhaust valve cooling method of the valve mechanism is characterized in that a part of hydraulic oil is introduced as a cooling medium into the inside of the valve body and circulated at the time of opening and closing operation of the exhaust valve.

According to the exhaust valve cooling method of the exhaust valve operating mechanism as described above, a part of the hydraulic oil is introduced into the inside of the valve body as a cooling medium and circulated when the exhaust valve is opened and closed. The exhaust valve can be reliably cooled by effectively utilizing a portion of the hydraulic oil used.

According to the present invention described above, a part of the hydraulic oil used for the valve operating mechanism of the exhaust valve can be effectively used for reliable cooling, and the reliability and durability of the exhaust valve can be improved. In addition, 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.

FIG. 2 is a view showing one embodiment of an exhaust valve operating mechanism, a diesel engine, and an exhaust valve cooling method of the exhaust valve operating mechanism according to the present invention, wherein a part of hydraulic oil introduced into the upper valve operating mechanism is guided inside a valve body It is principal part sectional drawing which shows the branch part of a refrigerant | coolant circulation flow path. It is principal part sectional drawing which shows the refrigerant | coolant circulation flow path provided in the inside of the valve body of an exhaust valve. It is principal part sectional drawing which shows the connection (flow) state of the refrigerant | coolant circulation flow path and the oil discharge flow path accompanying opening / closing operation | movement of an exhaust valve, and since both flow paths do not connect, hydraulic oil shows the non-flowing state. FIG. 6 is a cross-sectional view of the main parts showing the communication (flow) state of the refrigerant circulation flow path and the oil discharge flow path accompanying the opening and closing operation of the exhaust valve, showing a state where both flow paths are in communication and the hydraulic fluid flows. It is sectional drawing which shows the piston stroke of a lower valve-operating mechanism, and shows a conventional structure. It is sectional drawing which shows the piston stroke of a lower valve mechanism, and shows the structure in the case of utilizing a part of hydraulic fluid for exhaust valve cooling. It is an explanatory view showing 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 a discharge oil flow path, (a) is 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 not preferable about the communication position of a refrigerant | coolant circulation flow path and a discharge oil flow path, (a) is the relationship of the exhaust valve lift with respect to a crank angle, (b) has shown the relationship of opening area with a crank angle. . It is a schematic block diagram of an exhaust valve actuating valve mechanism provided with an exhaust valve which is opened using a driving force transmitted from a lower valve operating mechanism to an upper valve operating mechanism by compressing hydraulic oil, and electronically controlled as the lower valve operating mechanism. The structural example of the exhaust valve which employ | adopted Formula is shown. It is a schematic block diagram of an exhaust valve actuating valve mechanism provided with an exhaust valve which is opened using a driving force transmitted from a lower valve operating mechanism to an upper valve operating mechanism by compressing hydraulic oil, and is a cam type as a lower valve operating mechanism. Shows a configuration example of an exhaust valve adopting

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of an exhaust valve operating mechanism, a diesel engine, and an exhaust valve cooling method for an exhaust valve operating mechanism according to the present invention will be described based on the drawings.
The diesel engine of the present embodiment is, for example, a diesel engine for a ship main engine, and includes an exhaust valve 5 which is opened using a driving force transmitted from the lower valve operating mechanism 10 to the upper valve operating mechanism 20 by compressing hydraulic oil. The exhaust valve valve mechanism 4 is provided.

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

Although the lower valve operating mechanism 10 shown in FIG. 8 operates the solenoid valve unit 11 having the

main valves

11a and 11b and pushes up the piston 13 in the hydraulic cylinder 12, it is an electronically controlled type, but is not limited thereto Absent. For example, as in the exhaust valve actuating mechanism 4A shown in FIG. 9, a cam type in which the piston 13 is pushed up by the cam 15 may be employed as the lower valve actuating mechanism 10A. In FIG. 9, reference numeral 16 in the drawing is a spring which biases the piston 13 downward.
The electronically controlled exhaust valve actuating mechanism 4 and the cam-type exhaust valve actuating mechanism 4A have the same configuration and operation on the side of the upper valve actuating mechanism 20 described later, regardless of which mechanism is employed.

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

Thus, the exhaust valve valve of the marine engine diesel engine provided with the exhaust valve 5 opened using the driving force transmitted from the lower

valve operating mechanism

10, 10A to the upper valve operating mechanism 20 by compressing the hydraulic oil. In the present embodiment, as shown in FIGS. 1, 2, 3A and 3B, the mechanism 4 is formed inside the valve body of the exhaust valve 5 to introduce a refrigerant circulation channel 30 for introducing a part of the hydraulic oil and And an oil discharge passage 40 provided through the housing 25 of the upper valve operating mechanism 20. The refrigerant circulation passage 30 and the oil discharge passage 40 communicate with the outlet opening 31 of the refrigerant circulation passage 30 and the inlet opening 41 of the oil passage 40 when the exhaust valve 5 is opened and closed. A flow is generated in a portion of the hydraulic oil introduced into the flow path 30.

The refrigerant circulation flow passage 30 is opened to the piston 23 so that the hydraulic fluid 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 flow path 30 provided inside the umbrella portion 5 b passes the position as close to the bottom as possible, all around, and passes through the shaft 5 a again to the outlet opening 31. That is, as for the umbrella portion 5b of the exhaust valve 5 where temperature rise easily occurs, it is desirable to provide the refrigerant circulation flow path 30 which passes through the entire circumference as close to the surface as possible.
Further, when the exhaust valve 5 is closed, the outlet opening 31 is opened to the inside of the air spring 21, but in order to prevent the 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 blocked 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 discharge passage 40 in the opening / closing operation range of the exhaust valve 5 Become.

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

According to the above-described embodiment, when the exhaust valve 5 is fully closed, there is no hydraulic oil supply from the lower valve mechanism 10, and accordingly, the exhaust valve 5 is biased upward from the air spring 21 and the seat is Close to the surface. At this time, the hydraulic fluid in the refrigerant circulation channel 30 remains in the channel without flowing because the outlet opening 31 is closed in addition to the supply of the hydraulic fluid.
However, when the lower valve operating mechanism 10 operates, a flow (arrow F) of the hydraulic oil flowing in the hydraulic oil flow path 6 is generated, and flows into the cylinder portion 22 of the upper valve operating mechanism 20. For this reason, the pressure of the hydraulic fluid acts on the piston 23 to generate a force to push down the shaft portion 5a downward. This force overcomes the bias of the air spring, and the piston 23 and the exhaust valve 5 are pushed down. Thus, the exhaust flow path 3 is in the open state.

Further, part of the hydraulic oil flowing into the cylinder portion 23 flows into the refrigerant circulation flow path 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 and are in communication with each other, the hydraulic oil in the refrigerant circulation channel 30 is indicated by an arrow f in the figure. To cool the exhaust valve 5. At this time, the hydraulic oil that has cooled the exhaust valve 5 flows out from the 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 the outflow. Therefore, the hydraulic oil in the refrigerant circulation flow path 30 circulates in the flow path only at the timing when the exhaust valve 5 operates and communicates with the oil discharge flow path 40 of the hydraulic oil, and the hydraulic oil having a low temperature is used. The exhaust valve 5 is cooled efficiently and reliably.

By the way, the piston stroke of the lower

valve operating mechanism

10, 10A, that is, the piston stroke given to the piston 13 in the hydraulic cylinder 12 is a part of the working oil (arrow f) due to the cooling of the exhaust valve 5 In order to compensate for the amount of oil discharged to 40, it is desirable to set a value corresponding to the amount of oil discharged from the hydraulic oil to the value required for the exhaust valve opening / closing operation.

Specifically, as shown in FIG. 4B, a piston stroke (H <H + .DELTA.H) obtained by adding a piston stroke .DELTA.H for compensating the amount of oil drainage to the conventional piston stroke H shown in FIG. 4A is set. . That is, the piston stroke of the present embodiment set in the lower valve mechanism 10 is longer by the amount of hydraulic oil supply equivalent to the amount of oil discharge compared to the case where exhaust valve cooling is not performed (conventional structure). It should be set.
4A and 4B show the electronically controlled exhaust valve actuating mechanism 4, but the same applies to a cam type exhaust valve actuating 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 (the communication position of the cooling oil passage) is a part of the hydraulic oil without affecting the engine performance. A setting that enables exhaust valve cooling using the above is desirable. Therefore, as shown in FIG. 5, the exhaust valve lift L determined by the fully closed position shown by the solid line and the open position of the exhaust valve 5 shown by the imaginary line is formed between the exhaust valve 5 and the seat portion. The exhaust valve lift L is set to be L1 or more (L ≧ L1), where L1 represents an exhaust valve lift amount equal to the sheet portion area Sa and the passage minimum area Sb set in the exhaust flow path 3.

FIG. 6 is an explanatory view of a preferable setting of the communication position of the refrigerant circulation flow passage 30 and the oil discharge flow passage 40. FIG. 6 (a) shows the relationship between the exhaust valve lift and the crank angle, and FIG. 6 (b) shows the relationship between the opening area (seat area Sa) and the crank angle.
The exhaust valve lift and the opening area of the exhaust valve 5 increase as the crank angle advances, and become smaller and close after maintaining a constant value within a predetermined crank angle range. The solid line in the figure indicates the case where the exhaust valve cooling is not performed, and the broken line indicates the portion that changes due to the exhaust valve cooling.

On the other hand, the effective area used for exhausting is the area shaded in FIG. 6B, and the area of the sheet portion (opening area) Sa is smaller than the passage minimum area Sb.
And as shown to Fig.6 (a), the exhaust valve lift L of the crank angle corresponding to the passage minimum area Sb becomes the exhaust valve lift amount L1 of "seat part area Sa = passage minimum area Sb."
Therefore, for the communication position of the cooling oil passage, if the exhaust valve lift L is set to a region where the value becomes larger than the exhaust valve lift L1 corresponding to the passage minimum area Sb, the reduction of the area caused by the exhaust valve cooling is used for exhaust The exhaust valve cooling can be performed without affecting the engine performance because the effective area is not shaded.

However, as shown in FIGS. 7 (a) and 7 (b), when the communication of the cooling oil passage is performed in the area within the effective area used for the exhaust, a part of the hydraulic oil is used for cooling and valve opening Since the amount that can be used for operation decreases, when the exhaust valve 5 is opened to discharge the combustion exhaust gas in the combustion chamber 2, a delay of the exhaust valve lift and the opening area occurs. That is, since the exhaust valve lift and the opening area shown by the broken line move in the direction in which the crank angle is advanced compared to the solid line display within the effective area used for the exhaust, the hatched portion shown in FIG. As a result, the engine performance is deteriorated due to the poor gas exchange. In other words, by setting the communication position of the cooling oil passage in a region where the exhaust valve lift L has a larger value than the exhaust valve lift L1 corresponding to the passage minimum area Sb, it corresponds to the hatched portion in FIG. This region is outside the effective area used for exhaust, and as a result, it is possible to prevent deterioration of engine performance due to poor gas exchange.

In addition, the exhaust

valve actuating mechanism

4, 4A of the diesel engine for a ship main engine according to the present embodiment described above compresses the hydraulic oil and transmits the driving force transmitted from the lower

valve actuating mechanism

10, 10A to the upper valve actuating mechanism 20. As an exhaust valve cooling method of the exhaust valve 5 which is opened by using, a part of hydraulic oil used in the exhaust

valve operating mechanism

4, 4A as a cooling medium at the time of opening and closing operation of the exhaust valve 5 is introduced into the valve body and circulated. As a result, it is possible to cool the exhaust valve 5 reliably by effectively utilizing a part of the hydraulic oil used for the exhaust

valve operating mechanism

4, 4A.

As described above, according to the present embodiment described above, it is possible to reliably cool by effectively using a part of the hydraulic oil used for the exhaust

valve operating mechanism

4, 4A, and the reliability and durability of the exhaust valve 5 can be obtained. Can be improved. Further, since a part of the hydraulic oil is effectively used, it is easy to change the structure of the diesel engine for ship main engine as compared with the case of providing a new refrigerant and refrigerant supply system.
The present invention is not limited to the above-described embodiment, and can be suitably modified without departing from the scope of the invention, such as being applicable to diesel engines other than similar marine main engines.

1 cylinder 2 combustion chamber 3

exhaust flow path

4, 4A exhaust valve operating mechanism 5 exhaust valve

5a shaft portion

5b umbrella portion 6

actuation flow path

10, 10A lower valve operating mechanism 11 solenoid valve unit 12 hydraulic cylinder 13 piston 15 cam 16 spring Reference Signs List 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 channel 31 outlet opening 32 inlet 40 oil drain channel 41 inlet opening 42 orifice (flow control unit)

Claims

In an exhaust valve valve mechanism provided with an exhaust valve that is opened using a driving force that compresses hydraulic oil and is transmitted from a lower valve mechanism to an upper valve mechanism,
A refrigerant circulation passage formed inside the valve body of the exhaust valve and introducing a part of the hydraulic oil; and an oil passage provided through the casing of the upper valve mechanism;
At the time of opening and closing operation of the exhaust valve, the outlet opening of the refrigerant circulation channel and the inlet opening of the oil discharge channel are communicated to generate a flow in a part of the hydraulic oil. mechanism.
The exhaust valve valve mechanism according to claim 1, wherein a flow rate control unit is provided in the oil discharge flow path.
The piston stroke of the lower valve operating mechanism is set by adding a value corresponding to the amount of oil discharged from the hydraulic fluid to a value necessary for the opening and closing operation of the exhaust valve. Exhaust valve valve mechanism described in.
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 the exhaust valve lift L equal to or larger than the exhaust valve lift amount (L1) equal to the sheet area and the passage minimum area The exhaust valve actuating mechanism according to any one of claims 1 to 3, wherein L L L1).
A diesel engine provided with the exhaust valve operating mechanism according to any one of claims 1 to 4.
In an exhaust valve cooling method of an exhaust valve operating mechanism having an exhaust valve which is opened by compressing hydraulic oil and using a driving force transmitted from a lower valve operating mechanism to an upper valve operating mechanism,
A method of cooling an exhaust valve of an exhaust valve operating mechanism, wherein a part of the hydraulic oil as a cooling medium is introduced into the inside of a valve body and circulated at the time of opening and closing operation of the exhaust valve.