JP2021063506A - Method and system for lubricating large low-speed two-stroke engine having sip lubrication oil injector - Google Patents

Abstract

To provide a system and a method for improving lubrication of a large low-speed two-stroke engine.SOLUTION: In lubrication using "Swirl Injection Principle (SIP)", lubrication is improved by locating a lubrication oil injector (4) closer to the TDC than 1/5 of the whole stroke of a piston, which is closer to the TDC than a typical marine diesel engine. This improvement can be achieved by reconstructing a cylinder liner (2) or by adding new mounting holes to a cylinder. In the case where such reconstruction is not possible, it is also possible to achieve improvement of the SIP principle by directing a spray toward the TDC, for example under an angle of more than 30 degrees or even more than 60 degrees when measured from a plane normal to the cylinder axis, or toward a position on the cylinder liner closer to the TDC as compared with the position of a SIP valve. It is also possible to combine these two improvements.SELECTED DRAWING: Figure 1c

Description

The present invention relates to a large low speed two stroke engine such as a marine diesel engine or a gas or diesel engine in a power plant equipped with a lubricating oil injector near the top dead center (TDC) of a piston in a cylinder.

Efforts are being made to reduce emissions from marine engines through a focus on environmental protection. This also requires ensuring that such engine lubrication systems are optimized. It also adds to the intensification of competition and the economic aspect of reduced oil consumption because it is a significant part of the operating costs of vessels. Proper lubrication despite reduced lubricating oil is a further concern, as reduced oil consumption should not compromise the life of diesel engines. Therefore, steady improvements related to lubrication are needed.

There are several different lubrication systems for large low speed 2-stroke marine diesel engines, including direct injection of lubricating oil onto the cylinder liner or injection of oil quills onto the piston surface.

Another method, commercially referred to as the "swirl injection type (SIP)", is relatively new, injecting a mist of lubricating oil into a scavenging air swirl inside the cylinder. Based on. Lubricating oil is attracted to cylinder top dead center (TDC) by a spiral upward swirl vortex and pressed outward against the cylinder wall as a thin, uniform layer. This method is described in detail in WO 2010/149162. The lubricating oil injector is a check valve that includes an injector housing that is internally provided with a reciprocating valve member, which is typically a valve needle. The valve member in the valve housing opens and closes the route of the lubricating oil to the nozzle opening according to an accurate timing by using, for example, the tip of the needle. In current SIP systems, atomized droplets are sprayed at a pressure of 35-40 bar, which is less than 10 bar used in systems that work with a small oil jet introduced into a cylinder. Substantially higher than the oil pressure of. In some types of SIP valves, high pressure oil is used to move the spring-loaded valve member away from the nozzle opening against the spring force, causing the high pressure oil to atomize from the nozzle opening. It will be released as drops. When the oil is discharged, the oil pressure inside the valve member drops, and the valve member returns to its original position until the next lubricating oil cycle in which the lubricating oil injector is supplied with the high-pressure lubricating oil again.

In such a large marine engine, a plurality of injectors are arranged in a circle in a plane perpendicular to the cylinder axis around the cylinder, and each injector is for delivering a jet or spray of lubricating oil into the cylinder. Includes one or more nozzle openings at the tip. Examples of SIP lubricating oil injector systems for marine engines are International Publication Nos. 02/35068, 2004/038189, 2005/121121, 2010/149162, 2012/126480, 2012/1264773. No. and 2014/048438, which are incorporated herein by reference.

Conventionally, the cylinder of an engine is constructed with an opening for an oil injector located at a distance of more than about one-third of the total stroke of the cylinder from the top dead center (TDC) of the cylinder. However, in order to increase the length of the cylinder, whether the lubrication nozzle should be moved further towards the TDC to maintain proper lubrication in the cylinder near the TDC, where high temperature and proper lubrication requirements are of paramount importance. Needs consideration. Regarding the oil quill applied directly to the piston, Miyake et al., Presented by the International Combustion Engine Conference at the CIMAC Shanghai Convention 2013, "Paper No. 177, Cylinder Liner and Piston Ring Lubrication Problem on Increased Stroke / Bore Ratio PAPER NO ..: 177 Cylinder liner and piston ring lubrication issues in resonance to increase stroke / bore ra-tio) ”discloses such consideration. In these experiments, it was found that the oil did not enter the combustion chamber when the lubrication valve was placed at a distance of 1.2 m from the TDC. From the viewpoint of oil recovery and sulfuric acid neutralization in the combustion chamber, it was found that rearranging the lubrication valve near 0.3 m from the TDC is advantageous because 67% of the oil enters the combustion chamber. However, with regard to the overall lubrication of the entire cylinder, the situation was greatly improved by the two-stage lubrication in which 20% of the oil entered the combustion chamber.

Compared to the case where the oil quill enters the upper part of the cylinder, when a part of the spray from the SIP valve nozzle is spirally drawn upward toward the TDC and enters the combustion chamber, and therefore the distance from the SIP nozzle to the TDC is long. SIP lubrication requires special consideration, as it still provides good lubrication. This is also the reason why the change from oil peeling by quill to SIP lubrication proved an improvement in general conditions. For these reasons as well, it is generally considered that moving the SIP injector closer to the TDC does not provide an improvement that justifies the modification of the cylinder liner. In particular, no improvement can be expected in relocating the oil quill lubrication valve as discovered by Miyake et al. Therefore, it is conceivable to move the quill nozzle or jet nozzle of the conventional lubrication system further toward the TDC, but in the SIP lubrication type lubricating oil spray, these considerations are unnecessary due to the spiral swirl vortex carrying the oil. I think that the.

International Publication No. 2010/149162 International Publication No. 2002/035068 International Publication No. 2004/038189 International Publication No. 2005/124112 International Publication No. 2010/149162 International Publication No. 2012/12648 International Publication No. 2012/126473 International Publication No. 2014/0484438 International Publication No. 2005/12212

However, despite the obvious advantages of these SIP lubrication systems, there are general unwavering motives for improvement.

Therefore, an object of the present invention is to improve this technique. In particular, the purpose is to improve lubrication by using a SIP valve. A further objective is to reduce cylinder wear in large low speed 2-stroke engines, especially marine diesel engines. These objectives are achieved by systems and methods for improving lubrication of large low speed two stroke engines, described in detail below.

The principle of SIP lubrication has been recognized since its introduction as an improvement over oil quill lubrication, as the spray lubricates the combustion chamber towards the TDC in a spiral, but more recently, the SIP injector has been replaced by the TDC. Improvements in lubrication in SIP lubrication were experimentally achieved by placing them closer together. In particular, it is experimental that the wear is much less than expected in the cylinder liner provided with the SIP spray injector at the point where the relative distance from the TDC is 1/8 instead of 1/3 of the total stroke distance of the piston. I understood. During the running-in of the engine (also called run-in or break-in) after replacing the cylinder liner, it was found that the wear of the new liner was less than the wear of the cylinder that had been operating for more than 1000 hours. .. This was the greatest surprise, as it is very well known that the wear of the engine during the break-in period after the cylinder liner replacement is much greater than the break-in period. Therefore, despite the previous general advantages and good performance of SIP lubrication when compared to other lubrication systems, further improvements were possible.

Experiments have been performed with SIP injectors located at points where the relative distance from the TDC is 1/8 of the total stroke, but the distance for improved SIP lubrication is typically about about the total stroke. It is considered that the position of the SIP injector, which is 1/3 closer to the TDC than that of the conventional engine, can be extended to 1/6 or even 1/5 of the total stroke. Due to the lengthy time of the experiment, there is still no experimental evidence that the effect is achieved at 1/6 and 1/5 relative distances, but a thorough technical consideration and initial qualitative signs. (First qualitative indications) seems to support this.

To relocate the SIP injector to the TDC, configure the cylinder liner with mounting holes closer to the TDC from the beginning, or add new mounting holes to the existing cylinder liner that are closer to the TDC than the original mounting holes. Can be done by.

If it is not possible to reconfigure the cylinder liner, including the injector mounting holes near the TDC, spray from the SIP injector towards the TDC, or a position on the cylinder liner closer to the TDC than the position of the SIP valve. By changing the spraying direction of the lubricating oil from the usual 0 to 20 degrees to a larger angle toward the TDC, for example, over 30 degrees and 45 degrees when measured from a plane perpendicular to the cylinder axis. It is also possible to improve the SIP principle at an angle of more than 60 degrees.

The improvement by directing the spray towards the region closer to the TDC is considered to be less efficient than the location of the spray injector within that region, for example due to structural constraints around the cylinder liner. It can be a useful alternative if the lubricating oil injector cannot be installed sufficiently close to the TDC. In some cases, the two methods described above can be combined with the placement of the injector near the TDC and the spraying towards the TDC, if it is known to be advantageous for optimization.

The term large low-speed two-stroke engine is intended for engines having, for example, cylinder diameters greater than 30 cm and even greater than 100 cm, sizes typically used for ships and power plants. A typical target engine is a diesel engine, but a gas-powered engine can also be used. This lubrication system and method is used especially for large low speed 2-stroke diesel engines in ships.

Such an engine includes a plurality of cylinders, in which a piston reciprocates along the longitudinal cylinder axis for a distance corresponding to the entire stroke between top dead center TDC and bottom dead center BDC. To do. The cylinder comprises a plurality of lubricating oil injectors that inject lubricating oil into the cylinder at various positions on the outer circumference, distributed along the outer circumference of the cylinder between the TDC and the BDC, eg, at the same angular distance. Each lubricating oil injector includes a spray nozzle having an opening for ejecting the spray. Most lubricant injectors have only one opening in the nozzle, but spray nozzles can also have multiple openings. The direction of spraying is defined as the average direction of the droplets being sprayed. In some embodiments, a mist-like spray, also called mist, from the first nozzle is directed at the cylinder liner and enters the area on the perimeter between the first and second nozzles.

The lubricating oil injector is functionally a control system configured to supply the lubricating oil to the lubricating oil injector with a predetermined lubricating oil through the corresponding pipe system and to control the injection timing of the lubricating oil into the cylinder. Be connected. This timing is further related to the rotation of the engine, for example, one injection is performed for each rotation, or one injection is performed for each second rotation. The timing of injection is determined by the periodic increase in pressure of the oil supplied to the lubricating oil injector. For example, when the oil pressure in the lubricating oil injector exceeds a certain threshold value, injection is performed.

In the SIP principle, each lubricating oil injector has a nozzle that extends into the cylinder. The nozzle is sized to deliver a spray containing droplets of atomized lubricating oil, also called oil mist, when the lubricating oil is supplied with a predetermined threshold of lubricating oil.

The control system uses the vortex movement of the scavenging air toward the TDC to mist by injecting a spray onto the scavenging air in the cylinder before the lubricating oil injector passes through the lubricating oil injector as the piston moves toward the TDC. It is also configured to disperse the mist-like droplets in the scavenging air and disperse them on the cylinder wall by carrying the shape-like droplets in the direction toward the TDC.

Specifically, the nozzle of the lubricating oil injector in the cylinder is arranged at a point where the first specific distance from the TDC is at least 1/5 of the total stroke of the piston. For example, this first particular distance is less than 1/6, less than 1/7, or less than 1/8 of the total stroke.

For proper SIP lubrication during engine operation, the spray containing atomized droplets of lubricating oil is placed in the cylinder by the lubricating oil injector before passing through the lubricating oil injector as the piston moves towards the TDC. It is repeatedly injected into the scavenging air. In the scavenging air, the vortex motion of the scavenging air toward the TDC causes the mist-like droplets to be carried in the direction toward the TDC, so that the mist-like droplets diffuse and disperse on the cylinder wall.

Atomization of the spray occurs when the pressure of the lubricating oil in the lubricating oil injector increases at the nozzle. This pressure is higher than 10 bar and is typically 25 to 100 bar for this high pressure injection. For example, 30-80 bar, optionally 35-50 bar.

For example, a lubricating oil injector includes a spray nozzle having an opening of 0.1 to 1 mm, for example 0.2 to 0.5 mm, that emits spray or mist droplets, also called oil mist.

Viscosity also affects atomization. Lubricants such as ExxonMobil®'s Mobile® 560VS used in marine engines have a typical kinematic viscosity of about 220 cSt at 40 ° C and 20 cSt at 100 ° C, which is from 202 to 202. It corresponds to a kinematic viscosity coefficient of 37 mPa · s. Other lubricating oils used in marine engines include other Mobilgard ™ oils and Castrol ™ Cyltech oils, which have approximately the same viscosity at 40-100 ° C., for example. All are useful for atomization when the diameter of the nozzle opening is 0.1-0.8 mm, and the lubricating oil has a pressure of 30-80 bar at the opening and a temperature of 30-100 ° C or 40-100 ° C. Has.

It is common for SIP lubrication that oil is not injected in the radial direction, which is the direction from the cylinder liner to the central cylinder axis. Instead, the nozzle opening of the lubricant injector is directed towards the cylinder wall in the spray direction with a tangential component greater than the radial component. The radial component is parallel to the direction from the lubricating oil injector toward the cylinder axis at the center of the cylinder, and the tangential component is parallel to the cylinder in the tangential direction. For example, the mist spray from the first nozzle is directed towards the cylinder liner into the area between the first nozzle and the next nozzle on the outer circumference. In many cases, the nozzles are arranged with the same angular distance between the nozzles around the cylinder in a plane perpendicular to the cylinder axis.

It is advantageous for the cylinder liner to include a groove extending along the spray direction from the nozzle opening for each lubricant injector so as not to prevent the propagation of the spray in this direction from being blocked by the material from the cylinder liner. is there.

A mounting hole for the lubricating oil injector could be provided from the beginning at a first specific distance from the TDC of the new cylinder liner, but the system would penetrate the cylinder liner closer to the TDC than, for example, the original mounting hole. It is also useful for modifying the injector to define additional mounting holes by drilling mounting holes. Optionally, both the original mounting holes at a distance and the additional holes close to the TDC can be used to mount the lubricant injector, but in many cases the mounting holes at a distance from the TDS will be blocked. It is not used for lubrication.

For example, a first mounting hole for a lubricant injector at a point where a particular distance from the TDC exceeds 1/5 of the total stroke of the cylinder, eg 1/4 or more than 1/3 of the total stroke. Set up. Then, at a point where the first specific distance from the TDC is 1/5 or less of the total stroke of the cylinder, for example 1/6 or less of the total stroke, or 1/7 or less or 1/8 or less of the total stroke. Modify the cylinder by defining a set of second mounting holes. After that, a lubricating oil injector is attached to the set of the second mounting holes, and spray injection is performed using the set of the second mounting holes. However, usually a distance closer than 1/8 of the total stroke is unnecessary.

In some practical embodiments, the lubricating oil injector includes an injector housing, and when the injector housing is attached to the cylinder wall, the nozzle tip at one end of the injector housing reaches the inside of the cylinder. For example, this nozzle tip is an integral part of the injector housing, but this is not always the case. When the cylinder liner is provided with a groove for spraying, the tip of the nozzle reaches the inside of the groove. The nozzle tip includes an opening extending from an internal cavity within the injector housing through the wall of the nozzle tip, and pressurized lubricating oil is discharged from the internal cavity through this opening to the outside of the injector housing. Lubrication. Inside the injector housing, a valve member that reciprocates between the open and closed states of the injector is attached. The valve member seals and covers the nozzle opening when in a closed state to prevent lubricating oil from approaching the opening. The valve member moves away from the nozzle opening during the open state in which the lubricating oil from the internal cavity is brought closer to the opening during the oil discharge stage from the nozzle opening. Lubricating oil release is stopped when the pressure in the chamber is sufficiently reduced. The reciprocating motion of the valve member is repeated at the correct timing according to the movement of the piston.

For example, the lubricating oil injector receives the lubricating oil from the control system into the internal cavity of the lubricating oil injector at a predetermined pressure. The internal cavity is provided between the nozzle and the valve member so that the capacity of the internal chamber increases as the valve member moves away from the nozzle opening. When the pressurized oil enters the internal chamber, it presses on the valve member, for example, the shoulder of the valve member to increase the capacity of the internal chamber, and when the pressure increases above a predetermined threshold pressure, the valve member opens the nozzle. It displaces from the chamber, clearing the way, and the lubricating oil from the internal cavity is discharged through the opening of the nozzle. In order to bring high pressure into the internal cavity, it is advantageous for the valve member to be initially stressed by a spring towards a position that covers and closes the nozzle opening. With each repeated lubrication cycle, lubricating oil is fed into the internal cavity at a high pressure, for example 25-100 bar, usually 30-80 bar, to move the valve member away from the opening. For example, the valve member is pressurized to increase the capacity of the internal cavity and drain the lubricating oil from the nozzle when the pressure of the lubricating oil on the valve member is greater than the pressure applied to the valve member by the spring. It has a shoulder that is pressed by the lubricating oil. In this case, the spring pressure determines the threshold pressure for releasing the spray.

Another example of a method of moving a valve member is an electromechanical system such as a solenoid that moves a magnetically responsive core or shell connected to the valve member. In this case, the valve member moves only when the oil pressure is high enough that the opening supplies a mist-like spray.

Examples of spray injectors for the SIP principle are described in WO 02/35068, 2004/038189, 2012/126480, 2012/124673, and 2014/048443 described above. Lubrication control systems are described in detail in WO 2010/149162. These disclosures are incorporated herein by reference.

As much as possible at the first specific distance of the cylinder liner, for example by preventing access for injector mounting by a cooling cap, or by providing a cooling channel inside the cylinder liner that breaks during modification. If it is not possible to provide a mounting hole for the injector in the vicinity, a method different from the method described above and described in more detail below can be used. This method is not considered to be as efficient as providing a lubricant injector near the TDC. However, it seems to improve lubrication for the prior art. Roughly speaking, the following method is a SIP that changes the spraying direction of the lubricating oil toward the TDC from the usual 0 to 20 degrees to an angle larger than 30 degrees, for example 45 degrees, and even larger than 60 degrees. It is a lubrication method. This angle is measured from a plane perpendicular to the cylinder axis. For example, this angle is 30-80 degrees, optionally 45-80 degrees or 60-80 degrees. By changing the spray direction toward the TDC, the lubricating oil is easily carried toward the TDC by the swirl vortex. In other words, increasing the angle of inclination of the spray helps the swirl vortex carry oil into the combustion chamber towards the TDC.

Normally, when mounting the lubricating oil injector near the TDC, the spraying direction with such a large inclination angle toward the TDC is unnecessary. However, in principle, it is possible to combine the mounting of the lubricating oil injector close to the TDC as described above with the spraying direction having an inclination angle larger than 20 degrees.

For example, a lubricating oil injector is provided at a point where a specific distance from the TDC exceeds 1/5 of the total stroke of the piston, for example, 1/4 of the total stroke. In many engines, a lubricating oil injector is provided at a point where the distance from the TDC is about 1/3 or more of the total stroke. At this time, the lubricating oil injector makes the first specific distance from the TDC less than 1/5 of the total stroke of the piston, for example, 1/6 or less, 1/7 or less or 1 / of the total stroke. It is attached to the area on the cylinder liner located between the points of 8 or less so that the spray direction is directed.

For example, this spraying direction is directed toward the cylinder wall, and the tangential component parallel to the tangential direction of the cylinder is larger than the radial component parallel to the direction from the lubricating oil injector toward the central axis of the cylinder. With respect to the spray direction angle, the cylinder liner can be adjusted with corresponding grooves that allow most of the spray to propagate unimpeded into the cylinder from the nozzle of the lubricating oil injector.

The term spraying as used herein is used to describe a lubricating oil that is released in the form of a mist, also called an oil mist. Although diesel oil also has some lubricating properties, it is particularly viscous, so the term lubricating oil is used for a different lubricating oil than diesel oil.

Between the first and second nozzles on the outer circumference, the spray is directed by the first nozzle in the quasi-tangential direction rather than in the radial direction, i.e. with a small angle between the tangents. To spray oil onto the cylinder liner, the liner is provided with a groove that allows the spray to propagate into the cylinder along a quasi-tangential path. When the direction of the spray is directed to a region close to the TDC, it is advantageous to provide a groove in the cylinder liner that allows the spray to propagate in this direction without being hindered. For example, this groove is hemispherical, allowing free adjustment of the spray direction without interfering with the propagation of the spray in the adjustment direction.

The tangential component in the spray direction helps the swirl vortex accelerate the oil mist during its spiral movement towards the TDC. However, in principle, it is possible to inject in the radial direction with the angle facing the TDC as described above.

In summary, improved lubrication in SIP lubrication is achieved by placing the SIP injector closer to the TDC than less than one-fifth, eg, less than one-eighth, of the total stroke of the piston. This arrangement is closer to the TDC than a conventional engine. This arrangement can be achieved by reconfiguring the cylinder liner or by adding new mounting holes to the cylinder. If such reconstruction is not possible, for example, towards the TDC at an angle greater than 30 degrees, greater than 45 degrees, or greater than 60 degrees when measured from a plane perpendicular to the cylinder axis, or An improvement in the SIP principle can also be achieved by directing the spray closer to the TDC than to the position of the SIP valve. It is also possible to combine the two methods described.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

It is a top view which shows the cylinder lubrication system in a large-sized low-speed two-stroke engine such as a marine diesel engine. It is a schematic side view which shows the cylinder lubrication system in a large-sized low-speed two-stroke engine such as a marine diesel engine. It is a figure which shows one type of lubricating oil injector. It is a figure which shows the lubricating oil injector of another type. It is a figure which shows the lubricating oil injector of yet another type. It is a figure which shows the experimental data of the engine which modified two cylinders into the lubricating oil injector close to TDC.

FIG. 1 shows a half of a cylinder of a large low-speed 2-stroke engine such as a marine diesel engine. The cylinder 1 includes a cylinder liner 2 inside the cylinder wall 3. A plurality of lubricating oil injectors 4 distributed along a circle are provided inside the cylinder wall 3, and the angular distances between adjacent injectors 4 are the same. The injector 4 receives the lubricating oil from the lubricant pump and the controller system 11 through the lubrication supply line 9. Generally, the supplied oil is heated to a specific temperature of, for example, 50-60 degrees. A part of the lubricating oil is returned to the pump by the lubricating oil return line 10. The lubricator pump and controller system 11 supply pressurized lubricating oil to the injector 4 with a pulse of accurate timing synchronized with the movement of the piston in the cylinder 1 of the engine. For this synchronization, the lubricator pump and controller system 11 includes a computer that monitors the actual state and motion parameters of the engine, including crankshaft speed, load and position, and the crankshaft position is within the cylinder. Indicates the position of the piston.

Each injector 4 has a nozzle 5 provided with an opening that discharges a mist of lubricating oil 7, also called oil mist, into the cylinder 1 under high pressure. For example, the nozzle opening has a diameter of 0.1 to 0.8 mm, such as 0.2 to 0.5 mm, and is 10 to 100 bar, for example 25 to 100 bar, or typically 30. At a pressure of ~ 80 bar, the lubricant is atomized in the form of a fine spray, as opposed to a small jet of lubricant. The swirl vortex 9 of the scavenging air in the cylinder 1 presses the spray 8 against the cylinder liner 2 so that the lubricating oil is evenly distributed on the cylinder liner 2. This lubrication system is known in the art as a "swirl injection type (SIP)". Typically, the cylinder liner 2 propagates the spray from the injector along the cylinder wall to lubricate the area between the two adjacent nozzles, or even longer and non-radial as shown. A groove 6 as shown is provided to provide sufficient space to support the transport of lubricating oil by the swirl vortex.

FIG. 1b shows a schematic view of the cylinder 2 including the piston 32 reciprocating between the bottom dead center BDC and the top dead center TDC slightly below the cylinder top 35 along the central cylinder shaft 33. The distance D of the lubricant injector from the TDC can be expressed in terms of length from the TDC, or as it is done herein in terms of the percentage of total stroke, which is the distance between the TDC and the BDC. It can also be expressed from.

FIG. 2a shows the first type of lubricating oil injector 4a. The generalization principle of this injector is similar to that disclosed in WO 02/35088, 2004/038189 or 2005/12212 for a single nozzle opening, or more than one. The nozzle opening is as disclosed in International Publication No. 2012/126480. These references provide further technical details and explanations in addition to the functions of the injectors shown herein, which are not repeated here for convenience.

The injector 4a includes an injector housing 12 having a nozzle tip portion 13, and one end of the nozzle tip portion 13 is integrated with the injector housing 12. The nozzle tip portion 13 is provided with a nozzle 14 having a nozzle opening 14'for discharging lubricating oil. The nozzle 14 also includes a duct 20 extending from the nozzle opening 14'through the wall 21 of the nozzle tip 13 into the cylindrical internal cavity 15 of the injector housing 12. A valve member 16 is provided inside the injector housing 12. The valve member 16 includes a stem 17 that is slidably guided to reciprocate within the plain bearing 23, although the stem 17 is a separate stationary portion within the injector housing 12 in the illustrated embodiment. , It can itself be part of the injector housing 12. A valve needle 18 as a coaxial longitudinal extension of the stem 17 is provided in the internal cavity 15 of the injector housing 12. The valve needle 18 has a diameter smaller than the diameter of the internal cavity 15, and the needle tip 22 at the end of the valve needle 18, such as a conical end, is the valve seat 19 at the second end of the duct 14. Lubrication flows into the duct 20 along the valve needle 18 and is discharged from the nozzle opening 14', and the duct 20 opens and the lubricating oil flows into the nozzle opening 14'and is discharged from here. ing. The positions of the valve member 16 and the valve needle 18 receive initial stress from the nozzle tip 13 due to the action of an appropriate spring pressure on the opposite end of the valve member 16, and the valve member 16 having the valve needle 18 is inside the cavity 15. It is offset rearward away from the valve seat 19 due to the increase in oil pressure. The oil is released when the displacement of the valve member 16 due to the hydraulic pressure overcomes the initial stress from the spring. In this way, the pressure of the released oil is adjusted by the spring force. This is explained in more detail in the prior art documents cited herein.

FIG. 2b shows a second type of lubricating oil injector 4b. The generalization principle of this injector is similar to that disclosed in WO 2014/048438. This reference also provides additional technical details and explanations in addition to the functions of the injectors shown herein, which are not repeated here for convenience.

The injector 4b includes an injector housing 12 having a nozzle tip portion 13, and one end of the nozzle tip portion 13 is integrated with the injector housing 12. The nozzle tip 13 is provided with a nozzle opening 14'that discharges lubricating oil. A valve member 16 is provided in the cavity 15 of the injector housing 12, and the valve member 16 is slidably arranged in the cylindrical cavity portion 15'at the stem 17 and the nozzle tip portion 13 of the injector housing 12. Includes a cylindrical sealed head 15 and the like. The position of the valve member 16 is initially stressed rearward away from the nozzle tip 13 by the spring 26 and offset forward by the hydraulic pressure acting on the rear 27 of the stem against the force of the spring 26 through the channel 28. By pushing the valve member 16 forward, the sealing head 25 slides away past the nozzle opening 14'and the lubricating oil can flow out of the internal cavity 15 through the nozzle opening 14'. Unless this is the case, the nozzle opening 14'is sealed and covered by a sealing head 25 that abuts the cylindrical cavity portion 15'at the nozzle tip 13.

FIG. 2c shows a third type of lubricating oil injector 4c. The generalization principle of this injector is similar to that disclosed in WO 2012/126473. This reference also provides additional technical details and explanations in addition to the functions of the injectors shown herein, which are not repeated here for convenience.

The injector 42 includes an injector housing 12 having a nozzle tip 13, which is provided with a duct 20 at the nozzle 14 and a nozzle opening 14'at the first end of the duct 20. The duct 20 extends from the nozzle opening 14'through the wall portion 21 of the nozzle tip portion 13 into the internal cavity 15 of the injector housing 12. A valve member 16 including a stem 17 that is slidably guided to reciprocate in the slide bearing 23 is provided in the cavity 15 of the injector housing 12, and the stem 17 is in the injector housing in this embodiment. Although shown as a separate stationary section, it can itself be part of the injector housing 12. The position of the valve member 16 receives an initial stress forward toward the nozzle tip 13 by the spring 26. In one possible retract mechanism disclosed in WO 2012/126473, an electric coil exerts an electromagnetic force on a valve member with a corresponding electromagnetic response portion. However, in principle, it is also possible to have a suitable configuration in which the valve member 16 is offset rearward against the force of the spring 26 by increasing the oil pressure in the cavity 15 acting on the valve member 16. The valve member 16 as a coaxial longitudinal extension of the stem 17 includes a valve needle 18 to which a sealed ball member 28 as part of the needle tip 22 is fixed, and the needle tip 22 has the valve closed. In the state, it is pressed against the valve seat 19 to close the duct 20, and in the state where the valve is open, the lubricating oil passes through the needle tip 22 including the ball 28 from the internal cavity 15 and enters the duct 20 to enter the nozzle opening 14. It is offset from the valve seat 19 by the distance that it can be released from. The internal cavity 15 is sealed rearward by the O-ring 31 towards the rest within the injector housing 12.

Typical dimensions of the injector housing are 10 to 30 mm in diameter and 50 to 130 mm in length, but the injector with the supply line connected to the rear end can be slightly longer. The valve member 16 typically has a length of 40-80 mm and a diameter at the stem of 5-7 mm, with the valve needle 18 having a smaller diameter. The typical diameter of the housing tip 13 is 6-10 mm, depending on the overall size of the injector housing 12. The diameter of the nozzle opening 14'is 0.1 to 1 mm, for example 0.2 mm to 0.7 mm.

FIG. 3 shows the measured values of a marine diesel engine of type 9S90ME-C9.2-TII manufactured by MAN B & W (registered trademark). Maximum liner wear was measured for the four cylinders. First cylinder Cyl. 1st and 2nd cylinders Cyl. In 2, these liners are of the same type after 1600 and 1800 hours of operation, respectively, but with mounting holes for the injector at a point where the distance from the TDC is about 1/8 of the total stroke, HJL Lubtronic ( Changed to a new liner with a SIP injector connected to the system. Third cylinder Cyl. 3 and additional cylinders Cyl. In No. 4, the SIP injector was installed after 1200 and 500 hours of operation with the conventional check valve, respectively.

All SIP injectors were supplied with lubricating oil from the HJL Lubtronic ™ system. The HJ Lubronic ™ system is an electronically controlled hydraulic lubricator that lubricates according to the load to reduce cylinder oil consumption and optimize cylinder conditions, resulting in a fresh cylinder for each piston stroke. Deliver oil. The HJ Lubronic ™ system receives information about the synchronization of the system with the engine's flywheel rotation and operates electronically with a local controller that uses engine load information as a control parameter for the system, electronically at each cylinder. Based on a controlled cylinder lubricator. It is possible to control each cylinder lubricator.

Comparing the curves of FIG. 3 before and after the change, the difference in slopes representing different wear rates can be seen from the graph. The rate of wear was about 0.08 mm / 1000 hours for the check valve, compared to about 0.03 mm / 1000 hours for the SIP Lubtronic ™ injection system.

As can also be seen in FIG. 3, the SIP valve at a distance of 1/8 and the SIP valve at a distance of 1/3 show almost the same wear rate. This is the most surprising result, as the wear during the initial operating period should be much higher than the wear of the cylinder liner after the break-in period. It is common knowledge in the art that the wear during the initial operating period is much higher than the wear of the cylinder liner after the break-in period. It is also described on the page. New liner with injector at 1/8 stroke wear much less during break-in phase than expected, and even lower than expected with SIP injector located 1/3 of stroke from TDC Therefore, it can be interpreted that much better lubrication is achieved by using a SIP system with a spray injector at a distance of 1/8 of the stroke rather than 1/3 of the stroke. This surprise stems from the fact that scavenging air was generally considered in the art to efficiently distribute lubricating oil to the TDC along the liner. However, in these experimental results shown in FIG. 3, placing the lubricant injector at a distance of 1/8 rather than 1/3 from the TDC results in lower wear near the TDC and thus better lubrication. It proved different in that it was.

These experiments were performed at a point where the distance from the TDC was 1/8 (0.125) of the total stroke, but 1/7 or 1/6 of the total stroke, and even 1/5 (= 0). The effect was remarkable up to the value of .20), whereas at a distance of 1/3 of the total stroke, it was surprisingly improved compared to various previous measurements using SIP injectors in marine diesel engines. It is reasonable to assume that no effect was observed.

The present invention is, top dead center of the piston in the cylinder (TDC) with a lubricant injector near, lubricated example marine diesel engines, or large low-speed two-stroke engines, such as gas or diesel engines in power plants Regarding the method.

Therefore, an object of the present invention is to improve this technique. In particular, the purpose is to improve lubrication by using a SIP valve. A further objective is to reduce cylinder wear in large low speed 2-stroke engines, especially marine diesel engines. These objectives are achieved by methods for improving lubrication of large low speed two stroke engines, described in detail below.

It is a top view which shows the cylinder lubrication system in a large-sized low-speed two-stroke engine such as a marine diesel engine. It is a schematic side view which shows the cylinder lubrication system in a large-sized low-speed two-stroke engine such as a marine diesel engine. For example, it is a figure which shows the cylinder lubrication system in a large-sized low-speed two-stroke engine such as a marine diesel engine. It is a figure which shows one type of lubricating oil injector. It is a figure which shows the lubricating oil injector of another type. It is a figure which shows the lubricating oil injector of yet another type. It is a figure which shows the experimental data of the engine which modified two cylinders into the lubricating oil injector close to TDC.

Claims (34)

A method of lubricating a large low-speed 2-stroke engine, in which the engine reciprocates along the longitudinal cylinder axis (33) for the distance between top dead center TDC and bottom dead center BDC corresponding to all strokes. A cylinder (1) including a piston (32) is provided, and the cylinder (1) is distributed along the outer circumference of the cylinder (1) between the TDC and the BDC and various on the outer circumference. The method comprises a plurality of lubricating oil injectors (4) for injecting lubricating oil into the cylinder (1) at various positions.
A step of providing the lubricating oil injector (4) with a spray nozzle (14) having an opening (14') for discharging the spray in the spray direction, which is the average direction of the droplets in the spray.
During the operation of the engine, before the piston (32) passes through the lubricating oil injector (4) while moving toward the TDC, a spray containing atomized droplets of the lubricating oil is injected with the lubricating oil. The step of repeatedly injecting into the scavenging air in the cylinder (1) by the vessel (4), and
The step of diffusing the mist-like droplets into the scavenging air,
The mist-like droplets are dispersed on the cylinder wall (3) by carrying the mist-like droplets in the direction toward the TDC by utilizing the vortex motion (9) of the scavenging air toward the TDC. Steps and
And the above method
Further including the step of providing the lubricating oil injector (4) at the first specific distance D from the TDC in the cylinder (1), the first specific distance is the said of the piston (32). Less than 1/5 of the total stroke,
A method characterized by that. The first specific distance D is 1/6 or less of the total stroke of the piston (32).
The method according to claim 1. The first specific distance D is 1/8 or less of the total stroke of the piston (32).
The method according to claim 1. The method comprises supplying the lubricating oil to the lubricating oil injector (4) at a pressure of 25 bar to 100 bar for high pressure injection.
The method according to any one of claims 1 to 3. The method comprises providing the lubricating oil injector (4) with a spray nozzle (14) having an opening (14') having a diameter of 0.1 to 0.8 mm for discharging the spray.
The method according to any one of claims 1 to 4. The method can propagate most of the spray unimpeded in the spray direction from the nozzle (14) of the lubricating oil injector (4) into the cylinder (1) toward the cylinder wall (3). The spraying direction includes a step of providing the groove (6) to be provided in the cylinder liner (2), and the spraying direction is parallel to the direction from the lubricating oil injector (4) toward the central axis (33) of the cylinder (1). The tangential component parallel to the tangential direction of the cylinder (1) is larger than the radial component.
The method according to any one of claims 1 to 5. The method is a modification of bringing the lubricating oil injector (4) closer to the TDC, at a specific distance of the cylinder (1) from the TDC to a specific distance greater than 1/5 of the total stroke. A set of first mounting holes for 4) and a second set of mounting holes at a first specific distance D of less than 1/5 of the total stroke of the cylinder from the TDC. The step of modifying the cylinder (1), the step of attaching the lubricating oil injector (4) to the set of the second mounting holes, and the step of mounting the set of the second mounting holes to inject the spray. Including steps to use for
The method according to any one of claims 1 to 6. The method further comprises the step of closing the set of the first mounting holes and the step of using only the second mounting holes for the lubricating oil injector.
The method according to claim 7. Use of the large low speed 2-stroke marine diesel engine lubrication method according to any one of claims 1 to 8. A system for lubricating a large low-speed 2-stroke engine, the engine reciprocates along the longitudinal cylinder axis (33) for the distance between top dead center TDC and bottom dead center BDC corresponding to all strokes. A cylinder (1) including a piston (32) is provided, and the cylinder (1) is distributed along the outer circumference of the cylinder (1) between the TDC and the BDC and various on the outer circumference. It has a plurality of lubricating oil injectors (4) for injecting lubricating oil into the cylinder (1) at various positions.
The lubricating oil injector (4) includes a spray nozzle (14) having an opening (14') that discharges the spray in the spray direction, which is the average direction of the droplets in the spray.
The lubricating oil injector (4) is configured to supply the lubricating oil to the lubricating oil injector (4) with a predetermined lubricating oil pressure and control the injection timing of the lubricating oil into the cylinder (1). Functionally connected to the control system (11)
The lubricating oil injector (4) is sized to supply a spray containing atomized droplets of lubricating oil when the lubricating oil is supplied by the predetermined lubricating oil pressure (14). A nozzle (14) extending into the cylinder (1) having a') is provided.
The control system (11) applies the spray to the lubricating oil injector (4) before the piston (32) passes through the lubricating oil injector (4) while moving toward the TDC. The mist-like droplets are injected into the scavenging air in 1) to diffuse the mist-like droplets into the scavenging air, and the mist-like droplets are utilized by utilizing the vortex motion (9) of the scavenging air toward the TDC. Is configured to disperse the mist-like droplets on the cylinder wall (3) by carrying in the direction toward the TDC.
The nozzle (14) of the lubricating oil injector in the cylinder is located at a first specific distance D from the TDC, the first specific distance being the full stroke of the piston (32). 1/5 or less,
A system characterized by that. The first specific distance D is 1/6 or less of the total stroke of the piston.
The system according to claim 10. The first specific distance D is 1/8 or less of the total stroke of the piston.
The system according to claim 11. The predetermined oil pressure is 25 bar to 100 bar.
The system according to any one of claims 10 to 12. The lubricating oil injector (4) includes a spray nozzle (14) having an opening (14') of 0.1 to 0.8 mm for discharging the spray.
The system according to any one of claims 10 to 13. The lubricating oil injector (4) is parallel to the tangential direction of the cylinder (1) rather than a radial component parallel to the direction from the lubricating oil injector (4) toward the central axis (33) of the cylinder. The cylinder liner (2) comprises a nozzle (14) having an opening (14') directed at the cylinder wall (3) such that the tangent component provides a larger spray direction, the cylinder liner (2) being the cylinder wall (3). From the nozzle opening (14') along the spray direction so that most of the spray propagates unimpeded along the spray direction from the nozzle opening on the path directed to 3). Includes a groove (6) for each lubricating oil injector (4) that extends,
The system according to any one of claims 10 to 14. The lubricating oil injector (4) includes an injector housing (12), which is the groove (12) when the injector housing (12) is attached to the cylinder wall (3). A spray nozzle (14) having a nozzle tip (13) reaching the inside of 6) at one end and having an opening (14') is provided in the nozzle tip (13), and the nozzle (14) is provided with a spray nozzle (14). The opening (14') extends from the internal cavity (15) in the injector housing (12) through the wall (21) of the nozzle tip (13) and from the internal cavity (15). Lubricating oil is discharged from the injector housing (12) through the opening (14') of the nozzle (14), and the injector (4) is in an open state inside the injector housing (12). A valve member (16) attached so as to reciprocate between the closed state and the closed state is provided, and the valve member (16) prevents the lubricating oil from approaching the opening (14'). When in the state, the opening (14') of the nozzle (14) is sealed and covered, and the lubricating oil from the internal cavity (15) is released during the oil discharge stage from the opening (14'). Can move away from the opening (14') during the open state of approaching the opening (14') of the nozzle (14).
The system according to any one of claims 10 to 15. The valve member (16) receives an initial stress from the spring (26) to cover the opening (14') of the nozzle (14), and the lubricating oil injector (4) is the control system (11). By receiving the lubricating oil from the above into the internal cavity (15) at a variable pressure via the pipe system (9) and correspondingly and repeatedly increasing the pressure of the lubricating oil in the internal cavity (15). The valve member (16) is repeatedly moved away from the opening (14'), and the lubricating oil from the internal cavity (15) is discharged through the opening (14') of the nozzle (14). Is configured as
The system according to claim 16. A large low-speed two-stroke marine diesel engine comprising the engine lubrication system according to any one of claims 10 to 17. A method of lubricating a large low-speed 2-stroke engine, in which the engine reciprocates along the longitudinal cylinder axis (33) for the distance between top dead center TDC and bottom dead center BDC corresponding to all strokes. A cylinder (1) including a piston (32) is provided, and the cylinder (1) is distributed along the outer circumference of the cylinder (1) between the TDC and the BDC and various on the outer circumference. The method comprises a plurality of lubricating oil injectors (4) for injecting lubricating oil into the cylinder (1) at various positions.
A step of providing the lubricating oil injector (14) with a spray nozzle (14) having an opening (14') for discharging the spray in the spray direction, which is the average direction of the droplets in the spray.
During the operation of the engine, before the piston (32) passes through the lubricating oil injector (4) while moving toward the TDC, a spray containing atomized droplets of the lubricating oil is injected with the lubricating oil. The step of repeatedly injecting into the scavenging air in the cylinder (1) by the vessel (4), and
The step of diffusing the mist-like droplets into the scavenging air,
The mist-like droplets are dispersed on the cylinder wall (3) by carrying the mist-like droplets in the direction toward the TDC by utilizing the vortex motion (9) of the scavenging air toward the TDC. Steps and
And the above method
A step of providing the lubricating oil injector (4) at a specific distance from the TDC, which is more than 1/5 of the total stroke of the piston (32).
A step of mounting the lubricating oil injector in a spraying direction (36) at an angle (37) that exceeds a specific angle of 30 degrees when measured from a plane (38) perpendicular to the cylinder shaft (33).
Including,
A method characterized by that. The angle (37) is 45 to 80 degrees.
19. The method of claim 19. The method is a step of mounting the lubricating oil injector in a spray direction (36) towards a region on the cylinder liner (2) located between the TDC and a first specific distance D from the TDC. The first specific distance D is 1/5 or less of the total stroke of the piston (32).
The method of claim 19 or 20. The first specific distance D is 1/6 or less of the total stroke of the piston.
21. The method of claim 21. The first specific distance D is 1/8 or less of the total stroke of the piston.
21. The method of claim 21. The particular distance exceeds one-third of the total stroke of the piston (32).
The method according to any one of claims 19 to 23. The method comprises supplying the lubricating oil to the lubricating oil injector (4) at a pressure of 25 bar to 100 bar for high pressure injection.
The method according to any one of claims 19 to 24. The method comprises providing the lubricating oil injector (4) with a spray nozzle (14) having an opening (14') having a diameter of 0.1 to 0.8 mm for discharging the spray.
The method according to any one of claims 19 to 25. The method can propagate most of the spray unimpeded in the spray direction from the nozzle (14) of the lubricating oil injector (4) toward the cylinder wall (3) in the cylinder (1). The spraying direction includes a step of providing a groove (6) to be provided in the cylinder liner (2), and the spraying direction is a radial direction parallel to the direction from the lubricating oil injector toward the central axis (33) of the cylinder (1). The tangent component parallel to the tangential direction of the cylinder (1) is larger than the component.
The method according to any one of claims 19 to 26. Use of the large low speed 2-stroke marine diesel engine lubrication method according to any one of claims 19 to 27. A system for lubricating a large low-speed 2-stroke engine, the engine reciprocates along the longitudinal cylinder axis (33) for the distance between top dead center TDC and bottom dead center BDC corresponding to all strokes. A cylinder (1) including a piston (32) to be lubricated is provided, and the cylinder (32) is distributed along the outer circumference of the cylinder (1) between the TDC and the BDC and various on the outer circumference. It has a plurality of lubricating oil injectors (4) for injecting lubricating oil into the cylinder (1) at various positions.
The lubricating oil injector (4) includes a spray nozzle (14) having an opening (14') that discharges the spray in the spray direction, which is the average direction of the droplets in the spray.
The lubricating oil injector (4) supplies the lubricating oil to the lubricating oil injector (4) via a pipe system (9) with a predetermined lubricating oil pressure, and also supplies the lubricating oil into the cylinder (1). Functionally connected to a control system (11) configured to control injection timing,
The cylinder (1) is sized to supply the lubricating oil injector (4) with a spray containing atomized droplets of the lubricating oil when the lubricating oil is supplied by the predetermined lubricating oil pressure. ) Is provided, and a nozzle (14) extending inside is provided.
The control system (11) applies the spray to the lubricating oil injector (4) before the piston (32) passes through the lubricating oil injector (4) while moving toward the TDC. The mist-like droplets are injected into the scavenging air in 1) to diffuse the mist-like droplets into the scavenging air, and the mist-like droplets are utilized by utilizing the vortex motion (9) of the scavenging air toward the TDC. Is configured to disperse the mist-like droplets on the cylinder wall (3) by carrying in the direction toward the TDC.
The lubricating oil injector (4) in the cylinder (1) is provided at a specific distance from the TDC, and the specific distance exceeds 1/5 of the total stroke of the piston, and the lubricating oil. The injector (4) is oriented in the spray direction (36) at an angle (37) that exceeds a specific angle of 30 degrees when measured from a plane (38) perpendicular to the cylinder axis (33).
A system characterized by that. The angle (37) is. 45 to 80 degrees,
The system according to claim 29. The lubricating oil injector (4) has an angle (37) toward a region on the inner wall (2) of the cylinder (3) located between the TDC and a first specific distance from the TDC. Oriented in the spray direction (36), the first particular distance is less than or equal to one-fifth of the total stroke of the piston.
The system according to claim 29 or claim 30. The first specific distance is less than or equal to 1/6 of the total stroke of the piston.
The system according to claim 29. The first specific distance is less than or equal to 1/8 of the total stroke of the piston.
The system according to claim 29. The specific distance is one-third or more of the total stroke of the piston.
The system according to any one of claims 29 to 31.

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