Lubrication system for large two-stroke engines using controlled mass flow rate at the injector nozzle

Abstract

This invention relates to large engines, specifically marine engines or power plant engines, and a method for lubricating the engine using injectors. The method and engine are configured for periodic operation, and in the injection phase, pressurized fluid is supplied via a common rail system to which all injectors are connected to lubrication oil supply conduits. The method and engine are configured to operate within the following parameters, where the values ​​of the six parameters are such that the cavitation number is less than 1.5, and the ratio of the resulting force acting on the needle to the mass of the needle is 50 m / s² for the intended operation. 2 It has been selected to exceed [a certain value].

Description

[Technical Field]

[0001] The present invention relates to a large internal combustion engine, for example, a large low-speed two-stroke engine, and a method for lubricating such an engine, as well as an injector and method for such an engine.

[0002] More specifically, the present invention relates to a large, low-speed operating two-stroke engine comprising a cylinder having a reciprocating piston inside, and a system, wherein the system is Lubrication oil supply unit, Multiple lubricant injectors are distributed along the circumference of the cylinder to inject lubricant into the cylinder at various positions along its circumference during the injection phase, A lubricating oil supply conduit that connects the lubricating oil supply unit to the lubricating oil injector. Equipped with, The engine is, The system further includes a control device that controls the amount and timing of lubrication oil injection by at least one lubrication oil injector. Each injector is It is fluidly connected to the lubricating oil supply conduit and has an inlet port for receiving lubricating oil from the lubricating oil supply conduit, A nozzle configured to inject lubricating oil into the cylinder from an inlet port during the injection phase, and having a nozzle opening extending into the cylinder, Equipped with, This method applies to the engine, The step of providing an adjustable valve in a nozzle, comprising a valve member and a valve seat, which opens and closes during the injection cycle to allow the flow of lubricating oil from the pressure chamber in the injector to the nozzle opening through the sac hole, The nozzle opening has a cross-sectional area A3, the sac hole has a cross-sectional area A2, and a cross-sectional area A1 is provided between the valve member and the valve seat. This method involves supplying pressurized liquid to a lubricating oil supply conduit in a periodic operation during the injection phase.

[0003] A large, low-speed operating two-stroke engine comprising a cylinder having a reciprocating piston inside, and a system, wherein the system is Lubrication oil supply unit, Multiple lubricant injectors are distributed along the circumference of the cylinder to inject lubricant into the cylinder at various positions along the circumference during the injection phase, A lubricating oil supply conduit connecting the lubricating oil supply unit and the lubricating oil injector, Equipped with, The engine is, A control device that controls the amount and timing of lubricant injection by at least one lubricant injector, The computer to which the control device is connected, Furthermore, Each injector is It is fluidly connected to a lubricating oil supply conduit and has an inlet port for receiving lubricating oil from the lubricating oil supply conduit, A nozzle configured to inject lubricating oil into the cylinder from an inlet port during the injection phase, and having a nozzle opening extending into the cylinder, In the nozzle, an adjustable valve comprising a valve member and a valve seat is provided to open and close during the injection cycle to allow the flow of lubricating oil from the pressure chamber in the injector to the nozzle opening through the sac hole. Equipped with, The nozzle opening has a cross-sectional area A3, the sac hole has a cross-sectional area A2, and a cross-sectional area A1 is provided between the valve member and the valve seat. The engine's operation involves periodic operation, during the injection phase, supplying pressurized fluid to the lubricating oil supply conduit.

[0004] Furthermore, the present invention relates to an injector for a large, low-speed operating two-stroke engine comprising a cylinder having a reciprocating piston inside and a lubrication system including a control device, wherein the injector is An inlet port is fluidly connected to a lubricating oil supply conduit and receives lubricating oil from the lubricating oil supply conduit, A nozzle having a nozzle opening extending into the cylinder, configured to inject lubricating oil into the cylinder from an inlet port during the injection phase, In the nozzle, an adjustable valve comprising a valve member and a valve seat is provided to open and close during the injection cycle for the flow of lubricating oil from the pressure chamber in the injector to the nozzle opening through the sac hole, Equipped with, The nozzle opening has a cross-sectional area A3, the sac hole has a cross-sectional area A2, and a cross-sectional area A1 is provided between the valve member and the valve seat. The injector operates in a periodic manner. During the injection phase, all injectors are configured to supply pressurized liquid via a common rail system connected to a lubricating oil supply conduit.

[0005] Please note that "adjustable" means the range over which the amount the needle is pulled and the time the needle is open can be controlled. However, it is also possible to use other types of valves.

[0006] Furthermore, the engine is The computer to which the control device is connected, or A mobile phone that communicates with the control device. Please note that it is possible to further enhance this feature.

[0007] Furthermore, the engine is At least one flow meter for measuring the flow rate of lubricating oil, It can provide even more. [Background technology]

[0008] Efforts are ongoing to reduce emissions from marine engines with an eye on environmental protection. This also includes the steady optimization of lubrication systems for such engines, particularly due to increasing competition. One economic aspect that is attracting increasing attention is the reduction of oil consumption, not only for environmental protection but also because it is a significant part of the operating costs of ships. A further concern is to ensure proper lubrication despite reduced oil consumption, as the service life of the engine must not be compromised by reduced oil consumption. Therefore, steady improvements in lubrication are required.

[0009] For the lubrication of large slow-speed two-stroke marine diesel engines, there are several different systems, including the injection of lubricating oil onto the cylinder liner or the injection of an oil quill into the piston ring.

[0010] An example of a lubricating oil injector for a marine engine is disclosed in European Patent No. 1767751, where a check valve is used to provide a path for the lubricating oil to the nozzle flow path inside the cylinder liner. The check valve has a reciprocating spring-loaded ball at the valve seat immediately upstream of the nozzle flow path, and the ball is displaced by the pressurized lubricating oil. The ball valve is a traditional technical means based on a principle dating back to the early last century, as disclosed in, for example, British Patent No. 214922 of 1923.

[0011] Compared with conventional lubrication, an alternative and relatively new lubrication method is commercially called the Swirl Injection Principle (SIP). This is based on injecting a spray of atomized droplets of lubricating oil into the scavenge swirl inside the cylinder. Due to the helical upward swirl, the lubricating oil is drawn towards the top dead center (TDC) of the cylinder and is consequently pressed outwards against the cylinder wall as a thin and uniform layer. This is described in detail in International Publication No. 2010 / 149162 and International Publication No. 2016 / 173601. The injector comprises an injector housing with a reciprocating valve member, typically a valve needle provided inside. The valve member, such as the needle tip, closes and opens the path for the lubricating oil to the nozzle opening according to precise timing adjustments. In current SIP systems, the spray with atomized droplets is usually achieved at a pressure of 35 - 40 bar. In comparison, this is considerably higher than the oil pressure of less than 30 bar, often less than 10 bar, used in systems that function with a high-density oil jet introduced into the cylinder. Also, in some types of SIP injectors, the high pressure of the lubricating oil is used to move a spring-biased valve member against the spring force in the direction away from the nozzle opening, and the highly pressurized oil is then released therefrom as atomized droplets. The release of the oil leads to a pressure drop of the oil against the valve member, and the valve member returns to its origin and remains there until the next lubricating oil cycle when the high-pressure lubricating oil is supplied to the lubricating oil injector again.

[0012] In such large marine engines, a number of injectors are arranged around the cylinder, and each injector has one or more nozzle openings for sending a jet or spray of lubricating oil into the cylinder from each injector. Examples of SIP lubricating oil injector systems in marine engines are disclosed in International Publication No. WO 2002 / 35068, International Publication No. WO 2004 / 038189, International Publication No. WO 2005 / 124112, International Publication No. WO 2010 / 149162, International Publication No. WO 2012 / 126480, International Publication No. WO 2012 / 126473, International Publication No. WO 2014 / 048438, and International Publication No. WO 2016 / 173601.

[0013] The optimization of spraying in SIP lubrication is steadily progressing. However, lubricating injectors have similarities with fuel injectors but also exhibit different behaviors and effects when compared. This is mainly due to different operating conditions of the injectors, resulting from different actions such as viscosity, surface tension, and liquid pressure. Therefore, the research results of fuel injection cannot be automatically transferred to lubricating oil injection, and the differences in behavior can be surprising in some cases.

[0014] In the case of SIP injection, in addition to the goal of minimizing oil consumption, accurately controlled timing adjustment is essential. For this reason, the SIP system is specially designed for rapid reaction response during the injection cycle.

[0015] With the introduction of the HJL Smartlube4.0 system, the performance of the lubrication system has been improved. However, regardless of disturbances such as changes in the type of lubricating oil, pressure and temperature, and mechanical wear of components within the lubrication system, a method is required to automatically ensure that the system supplies the desired amount of lubricating oil and also ensure that most of the supplied lubricating oil is supplied in the form of a spray.

[0016] One important factor for atomization is cavitation within the nozzle, which is the formation of vapor or gas cavities within the liquid due to low static pressure. Cavitation within the nozzle causes significant turbulence in the liquid flow, destabilizing the jet and thus affecting the atomization of the liquid. While cavitation within nozzles has been extensively studied in the fuel injection field, there has been little research on cavitation in lubricating oil injectors.

[0017] International Publication No. 2018 / 215645 discloses a system referred to in the introductory paragraph and defined in the premise of an independent claim. A detailed description of the formation of vapor or gas cavities is disclosed in the applicant's International Publication No. 2018 / 215645. An explanation of cavitation is disclosed in International Publication No. 2018 / 215645.

[0018] To the extent that these research conclusions can be applied to lubrication injection, lubrication injection behaves differently from fuel injection due to its different viscosity, and cavitation at the nozzle exit is undesirable. In other words, parameters such as nozzle dimensions, as well as lubrication pressure and viscosity, must be selected to avoid cavitation, especially at the nozzle exit. This is consistent with the latest commercial SIP injection systems for marine engines, which operate with parameters that do not generate cavitation within the nozzle.

[0019] Because there is a certain motivation to improve lubrication in large two-stroke gas and diesel engines, such as marine engines or power plant engines, cavitation design is advantageously part of the considerations for optimizing the spray, particularly in SIP injection.

[0020] As described above, conventional lubrication techniques have concluded that cavitation, particularly near the nozzle tip, is detrimental to spray stability and lubrication distribution, and reduces spray controllability. Therefore, cavitation is not actually utilized in lubrication of large marine engines (regardless of whether it is jet injection or SIP injection). The parameters for spray injection, and more specifically SIP injection, are set outside the range where cavitation occurs.

[0021] However, contrary to the conclusions of prior art and trends in this field, further detailed research has surprisingly revealed that cavitation of lubricating oil within the nozzle can be used to achieve stable, controlled spray injection and uniform lubricating oil distribution, which is a crucial factor for optimized SIP lubrication.

[0022] Research relating to the invention disclosed in International Publication No. 2018 / 215645 has shown that not only is cavitation itself beneficial for the formation of lubricating oil sprays, but that when cavitation extends to the nozzle exit, the quality, controllability, and stability of the spray are further improved.

[0023] Furthermore, further research related to the present invention has shown that it is beneficial to control the increase in the mass flow rate of lubricating oil passing through the nozzle at the start of injection.

[0024] It is known that valve opening significantly impacts the speed at which the design operation is reached. Since cavitation at the nozzle tip is necessary for the valve to form a spray, it is crucial to achieve cavitation as quickly as possible when the valve is opened.

[0025] Therefore, it is desirable to provide a system that can quickly achieve cavitation and ensure the supply of a large amount of lubricating oil in spray form.

[0026] Prior art literature does not disclose any injector control methods or systems for rapidly achieving cavitation and supplying large quantities of lubricating oil in spray form. [Prior art documents] [Patent Documents]

[0027] [Patent Document 1] European Patent No. 1767751 [Patent Document 2] British Patent No. 214922 [Patent Document 3] International Publication No. 2002 / 35068 [Patent Document 4] International Publication No. 2004 / 038189 [Patent Document 5] International Publication No. 2005 / 124112 [Patent Document 6] International Publication No. 2010 / 149162 [Patent Document 7] International Publication No. 2012 / 126480 [Patent Document 8] International Publication No. 2012 / 126473 [Patent Document 9] International Publication No. 2014 / 048438 [Patent Document 10] International Publication No. 2016 / 173601 [Patent Document 11] International Publication No. 2018 / 215645 [Overview of the Initiative] [Problems that the invention aims to solve]

[0028] The object of the present invention is to improve the conventional system in order to achieve the desired effect by rapidly achieving cavitation and supplying a large amount of lubricating oil in the form of a spray.

[0029] In particular, the objective is to improve lubrication by SIP injectors or common rail systems in large internal combustion engines, such as large, low-speed two-stroke engines.

[0030] Furthermore, in order to establish cavitation at the nozzle tip and generate a spray, the goal is to achieve cavitation as quickly as possible by accelerating the mass flow during injection, thereby improving lubrication by the SIP injector or common rail system.

[0031] However, the method according to the present invention can also be used for large four-stroke internal combustion engines, such as marine engines or power plant internal combustion engines. [Means for solving the problem]

[0032] These objectives are achieved by a method for lubricating a large internal combustion engine, such as a low-speed two-stroke engine, equipped with multiple injectors according to the present invention. This method is configured to operate within a set of parameters described later. This method is defined in claims 1 and 9.

[0033] These objectives can also be achieved by a large internal combustion engine equipped with multiple injectors, such as a low-speed two-stroke engine. This engine is configured to operate within a set of parameters described later. A large low-speed internal combustion engine is defined in claim 2.

[0034] These objectives can also be achieved by the injector defined in claim 8.

[0035] The lubricating oil supply conduit is preferably a common rail.

[0036] Preferably, the lubricating oil supply unit is a high-pressure unit. Preferably, the high-pressure unit includes a pump.

[0037] Preferably, the lubrication supply system is the HJL Smartlube 4.0 system.

[0038] The present invention is applicable to a lubrication principle in which an injector receives pressurized lubricating oil from a lubricator via a single lubricating oil supply conduit to each injector.

[0039] The present invention is also applicable to lubrication principles in which multiple lubrication supply conduits are replaced by a single common lubrication supply conduit. In this case, the conduit connections supply lubrication to the injectors via a "common rail" system, in which all injectors for an engine cylinder, or a subgroup of injectors for a single engine cylinder, receive lubrication in common and simultaneously through a single lubrication supply conduit.

[0040] A return line is provided to optionally allow the lubricating oil to flow back from the injector.

[0041] A large two-stroke engine comprises a cylinder with a reciprocating piston inside, and multiple lubricant injectors distributed along the circumference of the cylinder for injecting lubricant into the cylinder at various positions within the cylinder during the injection phase. For example, the engine may be a marine engine or a large engine in a power plant. Typically, the engine burns fuel oil.

[0042] The term "injection phase" is used for the period during which the injector injects lubricating oil into the cylinder. The term "injection cycle" is used for the period between the time the injector injects lubricating oil into the cylinder and the next injection. This terminology is consistent with the prior art described above.

[0043] In this specification, the term “injector” is used in a lubricating oil injection valve system comprising a housing having a lubricating oil inlet and a single injection nozzle from which lubricating oil is ejected as a spray into a cylinder from a nozzle outlet, the nozzle outlet having an outlet opening of outlet dimension S. For example, the outlet opening is circular with diameter D, in which case diameter D is a measure of dimension S. If the outlet opening is not circular, the potential measure of dimension S is the opening area or average diameter, the latter being useful when it is elliptical or slightly elliptical from circular. For example, in the case of a non-circular outlet opening, the cross-sectional dimension is the equivalent diameter, calculated as twice the square root of the ratio between the cross-sectional area and the number Pi ≈ 3.14. The nozzle has one or more nozzle outlets, typically not greater than two.

[0044] In a SIP injector, the nozzle has a spray hole formed as a flow path with a length L between, for example, 0.5 and 1 mm, with one end forming the nozzle outlet. In a typical injector, the nozzle has a sac hole for the flow of lubricating oil into the spray hole, and the spray hole extends from the sac hole to the nozzle outlet. Typically, the central longitudinal axis of the spray hole forms an angle with the central longitudinal axis of the sac hole, for example, in the range of 30 to 90 degrees. Often, the cross-sectional area of ​​the sac hole perpendicular to its central longitudinal axis is larger than the cross-sectional area of ​​the spray hole perpendicular to its central longitudinal axis.

[0045] Optionally, a control unit is provided as an add-on system for upgrades. The control unit comprises a computer or is connected to a computer electronically or wirelessly. Advantageously, the computer is configured to monitor parameters relating to the actual state and motion of the engine. In cooperation with the computer, and based on the parameters, the control unit controls the amount and timing of lubricating oil injection by the injector during the injection phase. Optionally, the engine is equipped with a control unit. As will become clearer below, in advantageous embodiments, the control unit is configured to also control the pressure of the lubricating oil and optionally the temperature of the lubricating oil.

[0046] As mentioned at the beginning, prior art concerning lubricating oil injection has concluded that cavitation, particularly near the nozzle tip, is detrimental to spray stability and lubricating oil distribution, resulting in a less controllable spray. Therefore, in practice, cavitation is not used in the injection of lubricating oil into large marine engines, in terms of jet injection or SIP injection. The parameters for spray injection, specifically SIP injection, were outside the range where cavitation could be achieved.

[0047] Only after the research disclosed in International Publication No. 2018 / 215645, which led to the present invention, have further studies been conducted to find a method for optimizing lubricant injection with cavitation in the nozzle of an injector.

[0048] Therefore, contrary to conclusions in the prior art and contrary to the trend in the field, further detailed studies have surprisingly revealed that cavitation for lubricating oil in a nozzle can be used to provide a uniform distribution of lubricating oil, which is a crucial factor for stable, controlled spray injection and optimized SIP lubrication.

[0049] Research leading to this invention has shown that cavitation is beneficial not only for the formation of lubricating oil sprays, but that extending cavitation to the nozzle exit further improves spray quality, control, and stability. Surprisingly, it has been found that it is possible to improve spray conditions for lubricating oil injection.

[0050] For spray generation to occur, the primary pressure drop must be above the last hole of the nozzle. This is the orifice equation for a pipe with a circular cross-section according to ISO 5167-1:2022; This can be explained by TIFF2026520739000002.tif14150. In equation (1), TIFF2026520739000003.tif6150 is mass flow rate, C dρ is the discharge coefficient, A0 is the area of ​​the restricted section (D2 in Figure 3), Y is the expansion coefficient (equal to 1 for incompressible fluids, which is a fair assumption for cylinder lubricating oil under given conditions) [Ravendran R, Jensen P, De Claville Christiansen J et al. Rheological behaviour of lubrication oils used in two-stroke marine engines. Industrial Lubrication and Tribology 2017; 69(5): 750-753. DOI:10.1108 / ILT-03-2016-0075], ΔP is the pressure difference across the restricted section, ρ is the fluid density before the restricted section, and β is the diameter ratio, which is the ratio of the diameter of the restricted section to the diameter of the pipe, β = D2 / D1, as shown in the cross-section of the circular pipe illustrated in Figure 3.

[0051] In equation (1), when β is small, the resulting flow is small, and when β is large, the resulting flow is large. This is true as long as β < 1. When β ≥ 1, there is no longer a limit. By rearranging equation (1) as shown in (2), we can see that the pressure loss on the limit decreases with increasing β, and vice versa. TIFF2026520739000004.tif11150

[0052] At the tip of the nozzle opening, the primary pressure loss is on A1, as shown in Figure 9. Ideally, for the nozzle to spray, the primary pressure loss needs to be on A3. If there is no restriction on A1, the primary pressure loss at the nozzle tip is on A3. This is the case when the area of ​​A1 is equal to that of A2.

[0053] The injector can increase the mass flow rate "relatively quickly." In Figure 12, it takes approximately 1 ms to increase the flow rate to 2.5, 3.5, and 4 bar, respectively, which can be converted to mass flow rate as shown in equation (2). The advantage of rapidly increasing the mass flow rate is that the flow velocity also increases. As shown in Figure 12, the cavitation number decreases at high speeds.

[0054] In Figure 12, the cavitation number can be read on the right axis. Generally, if the cavitation number is 1.5 or less, it can be expected that the liquid will undergo cavitation and become more fragmented, that is, more atomized. In some cases, this can be the difference between whether or not oil is fragmented.

[0055] What is important in this invention is the time it takes for the injector to reach cavitation, or the cavitation count, less than 1.5.

[0056] Atomization of the lubricating oil is advantageous, and controlling how quickly the mass flow rate should be increased is important, which in turn allows for control of cavitation and thus atomization. It is advantageous to avoid areas without spray, and therefore areas where the desired effect cannot be obtained. In summary, it is advantageous that the majority of the injected lubricating oil is injected as a spray by controlling the mass flow rate exiting the injector.

[0057] For a lubricating oil to cause cavitation, the cavitation number must be less than 1.5. The cavitation number is shown in equation (3). TIFF2026520739000005.tif13150

[0058] In equation (3), P a This is the ambient pressure (pressure in the cylinder during injection), P v ρ is the vapor pressure of the fluid, ρ is the fluid density, and V is the fluid velocity. Most of the variables in equation (3) are constant, and P a Since ρ changes slightly with engine load and ρ changes slightly with temperature, these effects are very small, and the biggest influence on the cavitation number is the velocity of the lubricating oil. ru. Keeping TIFF2026520739000006.tif6150 in mind, equation (1) shows that the number of cavitations decreases as ΔP increases.

[0059] This means that for the nozzle to cause cavitation, the needle must be retracted to such an extent that the primary pressure drop exceeds that of the spray hole A3. Otherwise, the fluid velocity will not be sufficiently high.

[0060] The effect of this invention is to ensure that the nozzle opens quickly. For the nozzle to reach cavitation at high speed, the needle needs to be detached from its seat at high speed. To this end, the valve is operated with the following parameters. (Table 1) TIFF2026520739000007.tif55155

[0061] Here, Newton's second law applies. F=m·α (4) Here, F is the sum of the forces acting on the needle (also called the resulting force), m is the mass of the moving object, and α is the acceleration of the moving object.

[0062] Alternatively, the maximum force pulling the needle can be between 15 and 20 N. This is especially true when a piezoelectric actuator is not used.

[0063] The limitations on needle mass are the largest possible iron needle and the smallest possible aluminum needle. The temperature is set by how hot the lubricating oil nozzle gets when it is in operation, and the viscosity of the lubricating oil is calculated in relation to the two temperatures using the following correlation. TIFF2026520739000008.tif8150

[0064] The area ratio is 0 when the nozzle is closed, and based on nozzles with an area ratio between 0.8 and 85 when the nozzle is open.

[0065] As mentioned above, achieving cavitation requires increasing the flow rate within the valve as quickly as possible. To achieve this effect with a larger mass, a greater force is needed to satisfy other conditions. Therefore, there are limits to using a small force with a large mass, and vice versa.

[0066] The parameter combinations given in Table 1 result in a ratio of the resulting force acting on the needle to the mass of the needle, as defined by equation (6), of 50 m / s² for the intended operation. 2 The combination must be such that it exceeds [a certain value]. This is independent of the needle's mass. Therefore, the combination of mass and force must be such that it satisfies equation (6).

[0067] Furthermore, the increase in flow rate was experimentally measured using Bosch injection rates.

[0068] As can be seen from Figure 10, the mass flow rate does not increase instantaneously even when the valve is opened. This is mainly due to the needle's movement speed. Because the mass flow rate does not increase instantaneously, the lubricating oil initially injected is not injected as a spray.

[0069] This can also be shown using the cavitation number defined in (3) and the formula for Bosch's injection rate method. Bosch's injection rate method is described in "Bosch W. The fuel rate indicator: A new measuring instrument for display of the characteristics of individual injection. SAE Technical Papers 1966; DOI:10.4271 / 660749" and is shown in formula (5). TIFF2026520739000009.tif9150

[0070] In equation (5), TIFF2026520739000010.tif6150 is the mass flow rate, ΔP is the pressure difference on the injector, Apipe is the cross-sectional area of ​​the measuring tube used in Bosch's injection rate principle, and α is the speed of sound in the fluid. Since ΔP in equation (5) can be measured, and both the tube area A and the speed of sound α are constant, the mass flow rate can be calculated. The mass flow rate is Using the definition in TIFF2026520739000011.tif6150 (where A is the flow channel area and ρ is the density), the flow velocity in the measurement tube can be calculated. Incompressibility and continuity Using TIFF2026520739000012.tif6150, the flow velocity in spray hole A3 can be calculated and used to calculate the cavitation number (3).

[0071] This is shown in Figure 11. As can be seen from this figure, cavitation occurs when the cavitation number is approximately 1.5 or less, so the nozzle can reach cavitation after about 1 ms. This is advantageous because the faster the cavitation of the nozzle, the sooner it can reach its intended function of atomizing the lubricating oil. During the period from 0 to 1 ms, the needle is pulled back and the mass flow is accelerated. After 1 ms, the mass flow stabilizes until the nozzle begins to choke and the mass flow rate decreases as the nozzle closes.

[0072] For an injector to perform its intended function quickly, it is important that the injector can operate within a predetermined parameter span.

[0073] Furthermore, as shown in equation (6), which is a rewritten version of equation (4), the ratio of the resulting force acting on the needle to the mass of the needle for the intended motion is 50 m / s². 2 It is also important to exceed that. TIFF2026520739000013.tif9150

[0074] Furthermore, for area ratios of 0.8 or greater, it is also important that the cavitation parameter C, as defined in International Publication No. 2018 / 215645, is greater than 0 for the intended operation, as shown in (7). TIFF2026520739000014.tif8150 Here, μ is the dynamic viscosity, P is the pressure, and D is the diameter of the spray hole. This is consistent with the definition in International Publication 2018 / 215645, and this also applies to all constants in (7).

[0075] Furthermore, the number of cavitations depends on the diameter ratio from equation (1), as shown in equation (8). TIFF2026520739000015.tif28150

[0076] A small diameter ratio indicates a large cavitation number, thus suggesting that cavitation does not occur when the diameter ratio is small. The diameter ratio can be replaced with other geometric ratios to better represent the shape; for example, in the case of a nozzle, an area ratio can be used. For the intended operation, it is also important that the cavitation number of (8) is less than 1.5.

[0077] Therefore, the values ​​of the six parameters shown in Table 1 are selected such that the cavitation number given by equation (8) is less than 1.5, and with respect to the intended operation, the ratio of the resulting force acting on the needle to the mass of the needle is 50 m / s². 2 Selected to exceed the limit.

[0078] In experimental testing, the pressure change measured by a gauge at the injector nozzle is used to calculate the volumetric flow rate through the nozzle.

[0079] Experimental tests have shown a good agreement between the amount calculated from pressure measurements and the amount actually injected.

[0080] The injection rates of SIP lubrication for cylinder lubrication, tested using the Bosch injection rate method, showed the following results. - The mass flow rate increases in about 1 ms until cavitation within the nozzle begins to choke the flow. Once choking begins, the cavitation becomes strong enough to atomize the oil. As a result, spray formation is faster, which is an advantage when using SIP for lubrication. - With respect to the mass flow rate of lubricating oil, the injection volume is almost linear as a function of the ramp time, which, along with rise and fall times close to 1 ms, makes it easy to accurately inject the exact amount of lubricating oil. -Bosch's injection rate method can predict the injection volume within approximately 5% of the added weight over almost the entire range of ramp time tests for a high-viscosity fluid called HydraWay HVXA15, which has properties similar to heated cylinder lubricants [Ravendran R, Jensen P, De Claville Christiansen J et al. Rheological behavior of lubrication oils used in two-stroke marine engines. Industrial Lubrication and Tribology 2017; 69(5): 750-753. DOI:10.1108 / ILT-03-2016-0075], allowing for accurate injection of lubricating oil with precision of several milligrams or more per injection, and the rapid rise and fall of mass flow rates opens up new possibilities for lubrication strategies, such as the ability to inject multiple times during a piston stroke, supplying the required amount each time.

[0081] The present invention includes a method for lubricating a large, low-speed, two-stroke engine comprising a cylinder with a reciprocating piston inside, and a system, the system being Lubrication oil supply unit, Multiple lubricant injectors are distributed along the circumference of the cylinder to inject lubricant into the cylinder at various positions along the circumference during the injection phase, A lubricating oil supply conduit connecting the lubricating oil supply unit and the lubricating oil injector, A flow meter for measuring the lubricating oil flow rate, Equipped with, The engine is, The system further includes a control device for controlling the amount and timing of lubricant injection by at least one lubricant injector. Each injector is It is fluidly connected to a lubricating oil supply conduit, and has an inlet port for receiving lubricating oil from the lubricating oil supply conduit, A nozzle configured to inject lubricating oil into the cylinder from an inlet port during the injection phase, and having a nozzle opening extending into the cylinder, Preferably, the nozzle includes an adjustable valve that opens and closes during the injection cycle to allow lubricating oil to flow from the pressure chamber in the injector to the nozzle opening, Equipped with, This method includes periodic operation.

[0082] Please note that "adjustable" means that the degree to which the valve should be open can be controlled. However, other types of valves can also be used. Furthermore, the degree of needle tension can also be controlled.

[0083] Optionally, the system may also include a lubricant return line connecting the lubricant supply unit and the lubricant injector.

[0084] In a specific embodiment, the method for lubricating a large, low-speed two-stroke engine involves the engine, The computer (11') to which the control device is connected, or The step includes providing a mobile phone, which is arranged to communicate with a control device.

[0085] In a specific embodiment, a method for lubricating a large, low-speed two-stroke engine includes the step of supplying pressurized fluid via a common rail system in which all injectors are connected to a common rail.

[0086] Furthermore, the system To provide one flow meter for all injectors in the engine, to provide one flow meter for all injectors in the cylinder, or to provide one flow meter for each injector in the engine. The flow rate of the lubricating oil must be measured with at least one flow meter. In a control device, the measured actual flow rate is converted into an actual quantity. Includes.

[0087] Furthermore, the system To provide one pressure gauge in the lubricating oil supply conduit, Measure the pressure of the lubricating oil in the lubricating oil supply conduit using at least one pressure gauge. In a control device, the measured pressure is converted into a mass flow rate. It can include...

[0088] The pressure measurements in the lubricating oil supply conduit can be used in the control unit to ensure that the desired pressure is established by adjusting the pump.

[0089] However, experiments have shown that pressure fluctuations within the cylinder when lubricating oil is injected are very limited. During operation, the pressure within the cylinder follows a so-called banana curve. The pressure rise during the initial stroke and injection time is limited. Therefore, the need to control and regulate the pressure is limited.

[0090] Alternatively, a pressure relief valve can be used to maintain the pressure in the lubricating oil supply conduit at the desired level. Such a pressure relief valve is calibrated and adjusted before operation to achieve the desired pressure for the injector being used.

[0091] In this way, more methods can be used to maintain a desired constant pressure within the lubricating oil supply conduit.

[0092] Furthermore, this system This may include operating within specified parameters to ensure that the nozzle opens quickly to accelerate the mass flow during injection.

[0093] This allows cavitation to be established at the nozzle tip in the shortest possible time, enabling rapid development of the spray.

[0094] Such a time can be less than 2ms, or preferably less than 1ms.

[0095] The control device can be integrated into the injector or connected to the injector via wired or wireless connection.

[0096] The control device can be connected to the flow meter by wire or wireless connection.

[0097] The control device can also be configured to control the type of lubricant used.

[0098] In some embodiments, the maximum retractable position of the plunger is the rearmost possible position, which is the furthest distance from the nozzle opening, but it is also possible to hold the plunger at a predetermined distance from the rearmost possible position.

[0099] By adjusting this distance, the stroke length is reduced relative to the maximum retractable position, thereby adjusting the injection volume of the next injection. The effect is similar to the screw-adjustable end stop in International Publication No. 02 / 35068, but the stroke length adjustment mechanism can be centrally located far away from the injector, which is in contrast to the injector in International Publication No. 02 / 35068.

[0100] The engine according to the present invention may be equipped with a hydraulically driven inlet valve system, and each injector is, An inlet port that is fluidly connected to a lubricating oil supply conduit and receives lubricating oil from there, A nozzle having a nozzle opening extending into the cylinder and configured to inject lubricating oil into the cylinder from the inlet port during the injection phase, In the nozzle, an outlet valve system is provided that opens and closes during the injection cycle to allow lubricating oil to flow into the nozzle opening. In order to receive and store a predetermined amount of lubricating oil from the inlet port before the injection phase, a pre-chamber inside the injector located between the lubricating oil inlet port and the outlet valve system, Equipped with, The outlet valve system is configured to open immediately when the pressure in the pre-chamber and outlet valve system rises above a predetermined pressure limit during the injection phase, allowing lubricating oil to flow from the pre-chamber to the nozzle opening via the outlet valve system, and to close the outlet valve system after the injection phase.

[0101] Furthermore, the engine is A pressure control port is fluidly connected to a pressure control conduit and receives pressurized liquid from there during the injection phase, A pressure chamber communicates with a pressure control port and periodically receives pressurized liquid from the pressure control port during the injection phase, and discharges it after the injection phase. A reciprocating hydraulic actuator-plunger that contacts a pressure chamber and is pre-stressed by a spring load from an actuator-plunger spring, configured for operation driven by pressurized fluid in the pressure chamber during the injection phase, and configured such that its operation during the injection phase causes a pressure increase in the lubricating oil in the pre-chamber exceeding a predetermined pressure limit, It can be equipped with.

[0102] The engine may further include a stroke length adjustment mechanism for variably adjusting the stroke length of a reciprocating hydraulic actuator-plunger. In such embodiments, the stroke length adjustment mechanism is configured to variably adjust the amount of pressurized fluid discharged from the pressure chamber during the injection phase.

[0103] The effect of the variable adjustment capability is similar to that of the screw-adjustable end stop in International Publication No. 02 / 35068, but the stroke length adjustment mechanism can be centrally located far away from the injector, which is in contrast to the injector in International Publication No. 02 / 35068.

[0104] In some practical embodiments, the stroke length adjustment mechanism includes a pressure regulator for variably adjusting the idle pressure in the pressure chamber during the injection phase, the idle pressure being lower than a predetermined upper limit so as to partially counteract the spring load from the actuator-plunger spring on the actuator-plunger, thereby variably adjusting the retracted position of the actuator-plunger.

[0105] The outlet valve system blocks back pressure from the cylinder, preventing lubricating oil from flowing into the cylinder unless the outlet valve is open. In addition, the outlet valve system facilitates a short closing time after injection, improving the precision of the timing and amount of lubricating oil injected.

[0106] An engine equipped with a hydraulically driven inlet valve system may operate according to a method that includes a stroke length adjustment mechanism configured to variably adjust the amount of pressurized fluid discharged from the pressure chamber during the injection phase, the method including adjusting the stroke length during the injection cycle by adjusting the amount of pressurized fluid discharged from the pressure chamber after the injection phase.

[0107] This engine and method may include a hydraulically driven inlet valve system known from International Publication No. 2019 / 114905.

[0108] Furthermore, the engine according to the present invention may be equipped with a hydraulically driven inlet valve system, and each injector is A lubricating oil inlet port for receiving lubricating oil from a lubricating oil supply conduit, A nozzle with an opening extending into the cylinder, which injects lubricating oil into the cylinder from the inlet port, In the nozzle, an outlet valve system is provided that opens and closes during the injection cycle to allow lubricating oil to flow into the nozzle opening. Equipped with, The outlet valve system is configured to open to allow lubricating oil to flow to the nozzle opening as soon as the pressure in the outlet valve system rises above a predetermined pressure limit during the injection phase, and to close the outlet valve system after the injection phase.

[0109] In such embodiments, each injector may be equipped with an electrically driven inlet valve system that is electrically connected to a control device and positioned between the lubricating oil inlet port and the nozzle, and which regulates the lubricating oil distributed through the nozzle opening by opening or closing the flow of lubricating oil from the lubricating oil inlet port to the nozzle in response to an electrical control signal received from the control device, wherein the inlet valve system is positioned upstream of the nozzle and far from the nozzle, and upstream of the outlet valve system and far from the outlet valve system.

[0110] According to a particular embodiment of this type, the inlet valve system may include an inlet check valve having an inlet valve member, which is pre-stressed toward the inlet valve seat by an inlet valve spring and is arranged to allow lubricating oil to pass from the lubricating oil inlet to the outlet valve system as the inlet valve member is displaced from the inlet valve seat against the force from the inlet valve spring, and the inlet valve system further includes an electrically driven rigid displacement member for displacing the inlet valve member from the inlet valve seat during lubricating oil injection.

[0111] To provide better control over the rate and amount of lubricating oil discharged by the injector, each injector is equipped with an electrically driven inlet valve system positioned between the lubricating oil inlet port and the nozzle, electrically connected to a control device, and for regulating the lubricating oil distributed through the nozzle opening by opening or closing the flow of lubricating oil from the lubricating oil inlet port to the nozzle in response to an electrical control signal received from the control device. The inlet valve system is positioned upstream of the nozzle and far from the nozzle, and upstream of the outlet valve system and far from the outlet valve system.

[0112] The inlet valve system of the injector delivers the amount of lubricating oil for injection by the time the inlet valve system remains open for the injection phase. The time is determined by the control unit.

[0113] An engine equipped with an electric drive inlet valve system operates according to a method that includes sending an electric control signal from a control device to the electric drive inlet valve system to initiate an injection phase; as a result, causing a flow of lubricating oil from a lubricating oil supply conduit through a lubricating oil inlet port, through the inlet valve system, and into a conduit that fluidly connects the inlet valve system to an outlet valve system; increasing the pressure within the conduit by the flow of lubricating oil into the conduit; opening the outlet valve system by the increased pressure to allow the lubricating oil to flow from the conduit to a nozzle opening; injecting the lubricating oil into the cylinder through the nozzle opening; at the end of the injection phase, changing the electric control signal from the control device to the inlet valve system; and closing the inlet valve system to supply lubricating oil from the lubricating oil inlet port to the conduit.

[0114] This engine and method comprise an electric drive inlet valve system known from International Publication No. WO 2019 / 114905. However, this engine differs in that it is configured to operate within the parameter ranges shown in Table 1.

[0115] Here, the values of six parameters are selected such that the cavitation number given by Equation (8) is less than 1.5, and the parameter combinations given in Table 1 are selected such that, with respect to the intended operation, the ratio of the resulting force acting on the needle to the mass of the needle exceeds 50 m / s 2 and above.

[0116] According to a further embodiment, this engine is particular in that the lubricating oil system is selected from a mechanically driven system, a hydraulically driven system, and a common rail system.

[0117] The principles according to the invention are adaptable and can be used in various lubrication systems.

[0118] In some embodiments, the method includes controlling the amount of lubricating oil by feedback control / regulation, such as PID control or more advanced model-based regulation.

[0119] The method and engine according to the present invention are particularly suitable for use in injecting lubricating oil into ring packs or injecting SIP into the cylinders of large marine engines or power plant combustion engines at a lubricating oil pressure in the range of 10 bar to 400 bar, preferably in the range of 25 bar to 100 bar. The method is also suitable for lubrication combining SIP injection and injection into ring packs.

[0120] Furthermore, the present invention relates to an injector for a large, low-speed two-stroke engine, comprising a cylinder having a reciprocating piston inside and a lubrication system including a control device, wherein the injector is It is fluidly connected to a lubricating oil supply conduit and has an inlet port for receiving lubricating oil from the lubricating oil supply conduit, A nozzle configured to inject lubricating oil into the cylinder from an inlet port during the injection phase, and having a nozzle opening extending into the cylinder, Equipped with, The injector is configured to operate periodically during the injection phase. During the injection phase, all injectors are supplied with pressurized fluid via a common rail system connected to a lubricating oil supply conduit, and the injectors are configured to operate within the parameters shown in Table 1.

[0121] Here, the values ​​of the six parameters are selected such that the number of cavitations given by equation (8) is less than 1.5, and the combination of parameters shown in Table 1 results in a ratio of the resulting force acting on the needle to the mass of the needle of 50 m / s² with respect to the intended operation. 2 Selected to exceed the limit.

[0122] The injector is The nozzle may further include an adjustable valve that opens and closes during the injection cycle to allow lubricating oil to flow from the pressure chamber in the injector to the nozzle opening.

[0123] The injector is intended for use in the method or engine according to the present invention.

[0124] In particular, the injector is used for SIP injection into the cylinders of large marine engines or internal combustion engines for power plants, at a lubricating oil pressure ranging from 10 bar to 400 bar, preferably from 25 bar to 100 bar.

[0125] definition The term "adjust" refers to a situation where the amount of lubricating oil is changed during engine operation to match the desired amount.

[0126] The term "adjust" refers to the situation where the amount of lubricating oil is changed during the calibration of an injector.

[0127] The term "injector" is used for an injection valve system comprising a housing with a lubricating oil inlet, one or more injection nozzles with nozzle openings as lubricating oil outlets, and a movable valve member within the housing for opening and closing the lubricating oil inlet to the nozzle openings. An injector has a single nozzle that penetrates the cylinder wall and extends into the cylinder (however, it is embedded in the cylinder wall to ensure the free movement of the piston), but the nozzle itself optionally has multiple openings when the injector is properly installed. For example, a nozzle with multiple openings is disclosed in International Publication 2012 / 126480.

[0128] The term "injection phase" is used to refer to the time it takes for lubricating oil to be injected into the cylinder by an injector.

[0129] The term "idle phase" is used to refer to the time between injection phases.

[0130] The term "idle state" is used to refer to the state of a component during the idle phase.

[0131] The term "idle phase position or orientation" is used to refer to the position or orientation of a movable component when it is idle during the idle phase, and is in contrast to the injection phase position.

[0132] The term "injection cycle" is used to refer to the time elapsed between the start of one injection sequence and the start of the next. For example, if an injection sequence consists of a single injection, then the injection cycle is measured from the start of one injection phase to the start of the next. Alternatively, an injection sequence may consist of multiple injections, for example, multiple injections above the piston before it passes the injector on its way to TDC, such as a first injection with one lubricant followed by another injection of another lubricant, possibly further lubricants and / or additives. Such double or multiple injections ensure that the oil is mixed within the cylinder before the piston reaches TDC. For example, there may be one injection cycle for each revolution of the engine. However, it is also possible to have one injection cycle after multiple engine revolutions.

[0133] The term "timing" of injection is used in reference to coordinating the start of the injection phase by the injector in relation to a specific position of the piston inside the cylinder.

[0134] The term "frequency" of injection is used in relation to the number of repeated injections by the injector per engine revolution. A frequency of 1 means there is one injection per revolution. A frequency of 1 / 2 means there is one injection every two revolutions. This terminology is consistent with the prior art described above.

[0135] The term "pressurized lubricant" is used to refer to lubricant supplied at a pressure high enough to be injected into a cylinder as an atomized spray. This is in contrast to oil injection via quills between piston rings. The pressure depends on the purpose and form of injection, but is usually above 10 bar. In the case of SIP injection, the pressure is generally higher, for example, above 25 bar.

[0136] The term "flow meter" is used to refer to a component that can measure flow, regardless of the method used, such as pressure difference, viscosity, temperature, or volume.

[0137] The term "pressure gauge" is used for any component that can measure the pressure in a lubricating oil, regardless of the method used, and is also used, for example, to determine the pressure difference.

[0138] Practical Embodiments Large engines, such as low-speed two-stroke engines, and optionally marine or power plant engines, comprise a cylinder with a reciprocating piston and a number of lubricating oil injectors fixed to the cylinder wall and extending through the cylinder wall. The injectors are distributed along the circumferential length of the cylinder and are configured to inject lubricating oil into the cylinder at various positions along its circumferential length during the injection phase. Large engines, such as low-speed two-stroke engines, are marine or power plant engines. Typically, these engines burn diesel or gaseous fuel.

[0139] Furthermore, the engine generally includes a lubrication oil supply unit having pressurized lubricating oil pressurized by a lubricating oil supply pump. Optionally, the engine may include two or more lubrication oil supply units, correspondingly two or more types of lubricating oil, and correspondingly two or more lubricating oil supply pumps.

[0140] Each of the multiple injectors is connected to its respective lubricant inlet to the lubricant supply unit via a corresponding lubricant supply conduit. Each lubricant supply unit includes a potential pressure source, usually a lubricant pump, which raises the pressure of the corresponding lubricant to an appropriate level. In the system described, it is sufficient to provide a constant lubricant pressure at the lubricant inlet of the injectors.

[0141] The injector is configured to suit the type of lubricant to be injected. The inlet can be used to supply and add not only lubricant but also potential additives. For example, the injector may optionally have multiple inlets, one of which is used for lubricants such as lubricant, and another for additives. The injector is equipped with a nozzle having one or more nozzle openings for injecting lubricant into the cylinder in the form of a spray.

[0142] The engine further includes a control device. The control device is configured to control the pressure and mass flow rate of the lubricating oil.

[0143] The control device can also be configured to control the amount and timing of lubricating oil injection from multiple injectors. The injection frequency can also be controlled by the control device at will.

[0144] For accurate injection, it is advantageous for the control system to be electronically connected to a computer, or to be equipped with a computer, in which case the computer monitors parameters related to the actual state and operation of the engine. Such parameters help in optimizing injection control.

[0145] Optionally, the control system is offered as an add-on system for upgrading existing engines.

[0146] A further advantageous option is to connect the control unit to a human-machine interface (HMI), which comprises a display for monitoring and an input panel for adjusting and / or programming parameters related to the injection profile and, optionally, the engine status.

[0147] Electronic data connections can be wired, wireless, or a combination thereof, as desired.

[0148] In a specific embodiment, the injector is equipped with a lubricating oil inlet for receiving lubricating oil from a lubricating oil supply conduit and injecting it into the cylinder. The lubricating oil inlet of the injector is connected to a lubricating oil supply unit via a lubricating oil supply conduit.

[0149] The injector has a lubricating oil passage from the lubricating oil inlet to at least one nozzle, and a nozzle opening for the lubricating oil to flow from the lubricating oil inlet through at least one nozzle into the cylinder.

[0150] The injector comprises one or more nozzles, for example, two nozzles. Each nozzle has a nozzle opening and extends into the cylinder to inject lubricating oil during the injection phase. Optionally, the nozzle has two or more openings. For example, a nozzle with multiple openings is disclosed in International Publication No. 2012 / 126480. In some embodiments, the injector comprises a single nozzle having a single nozzle opening.

[0151] In detail, each injector is equipped with an internal actuator-driven valve system within the lubricating oil passage, which is configured to selectively switch from an idle state with no lubricating oil injection to an injection state in which lubricating oil is injected into the cylinder through at least one nozzle during the injection phase, in response to an injection phase signal received.

[0152] Each injector is equipped with an actuator for driving a valve system. The actuator is functionally connected to a control unit and is operated by the control unit to selectively drive the valve system, resulting in the injection of lubricating oil as a result of the actuator operation under the control of the control unit. The valve system is used to select the amount and timing used for injection, as well as the injection sequence, under the control of the control unit.

[0153] During operation, the actuator is activated by the control unit to initiate the lubricating oil injection phase. As a result, the valve system is opened, allowing lubricating oil to flow through the passage and be injected into the cylinder. At the end of the injection phase, the actuator is closed to stop the supply of lubricating oil.

[0154] Examples of pressure control In certain embodiments, the engine comprises a lubricating oil supply conduit containing lubricating oil at a first pressure and a pressure control conduit containing pressurized fluid at a pressure higher than the first pressure. In such cases, the injector comprises an internal hydraulically driven pump system, where pressurized fluid is used to drive the pump system inside the injector housing, thereby pressurizing the lubricating oil within the injector and releasing it therefrom. The injector comprises a lubricating oil inlet port, which is fluidly connected to the lubricating oil supply conduit and receives the lubricating oil from there for injection into the cylinder. The injector also comprises a pressure control port, which is fluidly connected to the pressure control conduit and receives the pressurized fluid from there during the injection phase.

[0155] The injector is equipped with a pre-chamber inside the injector between the lubricant inlet port and the outlet valve system to receive and store a predetermined amount of lubricant from the inlet port before the injection phase.

[0156] The pressure chamber within the injector communicates with a pressure control port and receives pressurized liquid from the pressure control port during the injection phase. The pressurized liquid in the pressure chamber drives the pump system within the injector.

[0157] The pump system includes a reciprocating hydraulic actuator-plunger that contacts the pressure chamber and is pre-stressed by a spring load from an actuator-plunger spring. The reciprocating hydraulic actuator-plunger is configured to be driven, for example, toward a nozzle by the pressurized liquid in the pressure chamber during the injection phase, thereby causing a pressure rise in the lubricating oil in the pre-chamber to exceed a predetermined upper limit, and pumping this predetermined amount of lubricating oil into the cylinder via a check valve and nozzle opening.

[0158] injection Optionally, the injection phase may consist of multiple injections, for example, multiple injections above the piston before it passes the injector on its way to TDC, such as a first injection of lubricating oil followed by another injection of another lubricating oil, and possibly further lubricating oil and / or additives. Such double or multiple injections ensure that the oil is mixed within the cylinder before the piston reaches TDC, especially in SIP operation.

[0159] A variety of injection sequences are possible through the control of the lubricating oil to be injected, the amount and timing of the injection, and various selections of these, for example, at least two of the following combinations are possible. - One or more injections below the piston, - One or more injections on the piston, - One or more injections above the piston during a single injection cycle.

[0160] Regarding various injections, the choice of lubricant(s), including additives, can be changed depending on the situation.

[0161] For example, the actuator is an electrically controlled actuator and is electrically connected to the control unit via an electrical connection to receive an injection phase signal from the control unit indicating the timing of injection. With respect to the injection phase, an electrical control signal is sent from the control unit to each injector to initiate the lubricating oil injection phase. As a result, the valve system opens, allowing the lubricating oil to flow through the flow path and be injected into the cylinder. At the end of the injection phase, the electrical control signal from the control unit to the injector is changed, the valve system closes to inject the lubricating oil, and the system returns to idle.

[0162] Optionally, the actuator comprises an electric solenoid configuration having a stationary solenoid section and a movable solenoid section. The valve system is coupled to the movable solenoid section, which is driven by the actuator when the solenoid is electrically excited, and the solenoid is configured to be excited by an injection phase signal from the control device.

[0163] The term "solenoid coil" should be understood as "at least one solenoid coil," as it is possible and sometimes advantageous to use two or more coils, for example, two or three coils.

[0164] The term "signal" from the control device is used here in relation to the current flowing from the control device to the injector. In some embodiments, if the current is strong enough, the signal itself can be used to drive an actuator, such as an electromechanical actuator. For example, to switch the direction of drive of an electromechanical actuator, the direction of the current is switched to the opposite direction. However, instead, the injector may have an electrical switch that opens to allow a current strong enough to drive the actuator when the signal from the control device is received. In the latter case, the signal line from the control device to the electrical switch can be implemented with very thin wiring. Alternatively, the term "signal" is also used for radio signals.

[0165] Alternatively, the actuator may be a hydraulic or pneumatic actuator. Such hydraulic or pneumatic actuators within the injector can also be electrically controlled at will. For example, an electrical signal from the control device to the injector opens the electromechanical actuator valve of the injector, creating a flow of hydraulic or pneumatic fluid into the actuator, and the valve system is driven by hydraulic or pneumatic fluid. At will, an electrical signal from the control device to the injector opens the electromechanical actuator valve, creating a flow of hydraulic or pneumatic fluid into the actuator, driving the actuator itself, and consequently driving the valve system by mechanical coupling.

[0166] In some embodiments, the valve system is configured to select only one injector at a time from a plurality of injectors for supplying and injecting lubricating oil. In some embodiments, alternatively or additionally, the valve system is configured to select two or more injectors at a time from a plurality of injectors for supplying and injecting lubricating oil, and to simultaneously inject lubricating oil in combination with multiple lubricants or additives.

[0167] In some embodiments, the injector has two or more nozzles, allowing multiple lubricants and additives to be injected into the cylinder through separate nozzles of the injector. In other embodiments, multiple lubricants and additives are injected into the cylinder through a single nozzle and, in some cases, mixed within the injector before being discharged from the nozzle opening.

[0168] In practical embodiments, the injector comprises a base and a rigid, voluntarily cylindrical fluid chamber, the fluid chamber rigidly coupling the base to the nozzle in order to fix the nozzle to the inside of the cylinder wall when the base is fixed to the cylinder wall. The base is located at the end opposite the fluid chamber relative to the nozzle, and is therefore usually located on the outer surface or outside of the cylinder wall. For example, the injector may have a flange on the base for mounting onto the outer wall of the cylinder. Alternatively, to mount the injector to the cylinder wall, the injector may have a flange provided around the fluid chamber. For example, the flange may be bolted to the cylinder wall.

[0169] Advantageously, the base comprises first and second inlets, and optionally further inlets. The flow chamber is hollow and includes a passage through which lubricating oil flows from the lubricating oil inlet through the flow chamber to the nozzle for injecting lubricating oil into the cylinder. Optionally, valve members are located within the flow chamber or the base.

[0170] For example, if the injector is mounted on the cylinder wall, the actuator is located on the outside of the cylinder wall. Optionally, the actuator can be fixed to a base.

[0171] In practice, the injection phase signal is received by the actuator, which then moves the valve member to the injection phase position or orientation in response to the injection phase signal, and in doing so, opens a passage for injecting lubricating oil into the cylinder.

[0172] For example, the actuator is mechanically coupled to a selected valve member by the actuator extension in order to drive the valve member with the actuator extension. This is advantageous when the valve member is located inside the flow chamber, and therefore inside the cylinder wall, while the actuator is located outside the cylinder wall. In this embodiment, the operation includes the step of moving the valve member with the actuator using the actuator extension.

[0173] Outlet valve system Optionally, each injector is equipped with an outlet valve system configured to open at the nozzle to allow lubricating oil to flow into the nozzle opening as soon as the pressure rises above a predetermined upper limit during the injection phase, and to close the outlet valve system when the pressure drops after the injection phase. The outlet valve system blocks back pressure from the cylinder and prevents lubricating oil from flowing into the cylinder during the idle phase between injection phases. In addition, the outlet valve system helps to improve the precision of the timing and amount of lubricating oil injected by providing a short closing time after injection.

[0174] In these embodiments, the injector includes a lubricating oil flow path from the lubricating oil inlet through the valve system and the outlet valve system for the lubricating oil to flow out of the injector at the nozzle opening. The valve system is positioned upstream of the nozzle as part of the injector and can be optionally separated from the nozzle. Optionally, the valve system is positioned upstream of the outlet valve system and can be optionally separated from the outlet valve system.

[0175] For example, an outlet valve system includes an outlet check valve. In an outlet check valve, an outlet valve member, such as a ball, ellipsoid, plate, or cylinder, is preloaded toward the outlet valve seat by an outlet valve spring. As soon as pressurized lubricating oil is supplied to the upstream flow chamber of the outlet valve system, the force of the preloaded spring is counteracted by the pressure of the lubricating oil. If the pressure becomes higher than the spring force, the outlet valve member is displaced from its outlet valve seat, and the check valve opens to inject lubricating oil into the cylinder through the nozzle opening. For example, the outlet valve spring acts on the valve member in a direction away from the nozzle opening, but the reverse movement is also possible.

[0176] For example, to lubricate an engine, the method comprises the steps of sending an electrical control signal from a control device to an injector, and using the control signal to cause the injector to open the inlet valve system in order to allow lubricating oil to flow from the lubricating oil supply conduit through the lubricating oil inlet, through the valve system, and into a conduit that fluidly connects the inlet valve system to the outlet valve system.

[0177] During the injection phase, it should be noted that the pressure of the lubricating oil in the lubricating oil supply conduit exceeds a predetermined upper limit that determines the opening of the outlet valve system, in order to supply lubricating oil at a pressure high enough to open the outlet valve system through the inlet valve system. Therefore, as the lubricating oil flows through the inlet valve system into the conduit between the inlet valve system and the outlet valve system, the pressure in the outlet valve system increases, and the outlet valve system opens to allow the lubricating oil to flow from the conduit to the nozzle opening, thereby injecting the lubricating oil into the cylinder through the nozzle opening. At the end of the lubrication time, the electrical control signal from the control device is changed so that the inlet valve system closes again to supply lubricating oil from the lubricating oil inlet to the nozzle opening. The pressure in the conduit decreases again, and the outlet valve system closes.

[0178] In these embodiments, at least two valve systems are present within the injector. The inlet valve system is controlled by a control device, for example, by an electrical signal from the control device, and once the inlet valve system is opened, a high-pressure flow of lubricating oil is generated from the lubricating oil supply conduit to the outlet valve system, the outlet valve system is operated solely by the high pressure of the lubricating oil in the outlet valve system. There is no mechanical coupling connecting the movable parts of the inlet valve system to the movable parts of the outlet valve system. The coupling between the opening and closing of these two systems is performed solely by the lubricating oil flowing from the inlet valve system to the outlet valve system.

[0179] Valve and actuator options details In some practical embodiments, the valve system includes a movable actuator-driven valve member arranged to move from an idle-phase position in which the valve member blocks the flow path during the idle phase to an injection-phase position in which the valve member opens the flow path and allows lubricating oil to flow through it during the injection phase. Advantageously, the valve member is pre-stressed toward the idle-phase position by a valve spring.

[0180] In some embodiments, to drive a movable valve member, the injector is movable and includes an actuator-driven rigid actuator extension, which couples the actuator with the valve system and is used by the actuator to displace or rotate the valve member from an idle phase position in which the valve member closes the flow path to an injection phase position in which the valve member opens the flow path to allow lubricant to flow through the flow path in order to inject lubricant into the cylinder during the injection phase.

[0181] Optionally, the actuator-driven rigid actuator extension is a pull-pull member that selectively pulls or pushes the valve member during injection. Alternatively, the actuator extension is a rotating member that transmits the driving force from the rotary actuator, for example, selectively in one direction or the other.

[0182] In some embodiments, the actuator is an electrically controlled actuator, such as an electromechanical actuator. Optionally, the actuator comprises an electric solenoid configuration having a stationary solenoid section and a movable solenoid section, wherein the actuator extension is coupled to the movable solenoid section to be driven by the electric excitation of the solenoid, and the solenoid is configured to be excited by an injection phase signal from a control device.

[0183] For example, a valve system may include a linear actuator for driving an actuator extension. In this case, the actuator extension is coupled to an actuator, such as a solenoid plunger and solenoid coil configuration, and when the actuator is electrically operated, the actuator extension, such as a push member, is driven to open, allowing flow from the lubricating oil inlet. Optionally, the actuator extension is coupled to a solenoid plunger, while the solenoid coil remains stationary within the injector. Alternatively, the actuator extension is coupled to a solenoid coil that moves with the actuator extension.

[0184] Alternatively, a piezoelectric element can be used to drive the valve member. Such an element is electrically or wirelessly connected to a control device and controlled by the control device in relation to contraction or expansion. By using a piezoelectric actuator, very high forces can be obtained, for example, as high as 10,000 N. Furthermore, this force can be high enough to shorten the time required to reach the operating state in which cavitation occurs during injection, and as a result the injected lubricant begins to take the form of a spray very quickly.

[0185] In some specific embodiments, the valve member is cylindrical and comprises a stationary valve member, resulting in a corresponding cylindrical bushing, in which the cylindrical valve member is positioned to be displaced along the longitudinal axis of the bushing, or to rotate about the longitudinal axis of the bushing.

[0186] The term cylindrical bushing is used to describe a bushing that has a cylindrical cavity and usually has a circular cross-section, although not necessarily so. Because the cylindrical valve member fits snugly into the cylindrical cavity of the bushing, no lubricating oil can flow between the cylindrical valve member and the cylindrical bushing, except for a potentially minimal amount that is negligible compared to the amount of lubricating oil injected into the cylinder, as it only lubricates the valve member inside the bushing.

[0187] System advantages The system described in this specification has many advantages.

[0188] By incorporating a valve system and an optional outlet valve system inside the injector, the mass of the movable parts that need to be moved during operation is reduced. Due to the reduced mass, the reaction time of the movable parts is shortened compared to conventional systems, and therefore this system is accompanied by improved reaction speed and corresponding accuracy in timing and volume.

[0189] The injector is generally less than a few times the thickness of the cylinder wall of such a large engine, for example, about twice as long, and extends through the opening in the cylinder wall. Therefore, the distance from the valve system to the nozzle opening is usually about the thickness of the cylinder wall or even less. For example, the distance from the valve system to the nozzle opening is less than 20 cm, or even less than 10 cm, which is much shorter than the several meters between the valve and nozzle in conventional technology. This means that the distance from the valve system to the nozzle outlet is extremely short, and the valve system has correspondingly short response times and precision.

[0190] Because the valve system is located within the injector housing and close to the nozzle, the injector has a short reaction time, allowing for high precision in injection timing and duration, with duration being equivalent to injection volume. Due to the high timing precision and fast reaction time, lubricating oil injection in a single injection cycle can be performed in multiple partial injections. The above-mentioned injector, including, for example, the outlet valve system, has only a short, rigid flow path from the valve system to the nozzle, so the minute compression and expansion of oil in relatively long conduits are avoided along with the expansion of the conduit itself, thus minimizing uncertainty and inaccuracy in injection volume and timing.

[0191] For example, within the time interval before the engine piston passes through the injector, especially when using the SIP principle, a double injection can be performed so that two types of lubricating oil are mixed in the cylinder.

[0192] Because a return line is unnecessary, this system requires only a single lubricating oil line to the injector, minimizing installation costs and labor, and reducing the risk of failure. This is especially true for large engines that would require return lines several meters long. Furthermore, it avoids inaccuracies in the time and amount of lubricating oil that can occur when closing the valve due to dead volume in the return piping.

[0193] The outlet valve system with a check valve ensures stability against the high pressure from the cylinder. When the outlet valve system includes a check valve in or on the nozzle, and the check valve comprises a valve member, such as a ball, that is spring-pressed against the valve seat, a high degree of robustness against failure has been observed. These systems are simple and have minimal risk of clogging. Furthermore, the valve seat, especially when the valve member is a ball, tends to be self-cleaning and resistant to uneven wear, thus providing high reliability over the long term. Therefore, the injector is simple, reliable, quick, accurate, and easy to assemble from standard components at low manufacturing cost.

[0194] In conclusion, certain valve systems operate quickly due to their lightweight components. Furthermore, the components have a relatively simple structure, suggesting low manufacturing costs. In addition to these advantages, valve systems are reliable, robust, and have a low risk of clogging. Also, because the components are subjected to relatively small pressure loads, valve systems have a long lifespan.

[0195] Any parameter For example, the injector is equipped with a nozzle having a nozzle opening of diameter D when the nozzle is circular, or with an equivalent diameter D that is twice the square root of the value obtained by dividing the nozzle opening area by pi when the nozzle is not circular, where the diameter D is at least 0.1 mm, and is configured to emit a spray of atomized droplets, also called oil mist. When lubricating oil is injected, cavitation is formed in the lubricating oil.

[0196] Atomized droplet spraying is crucial in SIP lubrication, where the lubricating oil is repeatedly injected into the scavenging chamber inside the cylinder before it passes through the injector as the piston moves toward TDC. During scavenging, the swirl motion of the scavenging chamber toward TDC carries the droplets toward TDC, causing them to diffuse and distribute across the cylinder wall. Atomization of the spray is achieved by high-pressure lubricating oil in the lubricating oil injector at the nozzle. For this high-pressure injection, the pressure is higher than 10 bar, typically between 25 and 100 bar. For example, it can range between 30 and 80 bar, and, if necessary, between 35 and 60 bar. The injection time is short, usually around 5-30 milliseconds (msec). However, the injection time can be adjusted to 1 millisecond, or even less than 1 millisecond, e.g., 0.1 milliseconds. Therefore, even a few milliseconds of inaccuracy can negatively impact the injection profile, hence the need for high precision, such as 0.1 milliseconds, as mentioned above.

[0197] Viscosity also affects atomization. Lubricants used in marine engines typically have a kinematic viscosity of approximately 220 cSt at 40°C and 20 cSt at 100°C, which translates to a viscosity between 202 and 37 mPa·s. An example of a useful lubricant is ExxonMobil®'s Mobilgard® 570VS (or the phased-out 560VS) high-performance marine diesel engine cylinder oil. Other useful lubricants for marine engines include other Mobilgard® oils and Castrol® Cyltech oil. Lubricants commonly used in marine engines have nearly identical viscosity profiles in the 40-100°C range, and are all useful for atomization when, for example, the nozzle opening diameter is 0.1-0.8 mm, the lubricant has a pressure of 30-80 bar at the nozzle opening, and the temperature is in the 30-100°C or 40-100°C range. See also the published paper on this subject by Rathesan, Peter Jensen, Jesper de Claville Christiansen, Benny Endelt, and Erick Appel Jensen, "Rheological Behavior of Lubricants Used in Two-Stroke Marine Engines," Industrial Lubrication and Tribology, 2017, Vol. 69, No. 5, pp. 750-753, https: / / doi.org / 10.1108 / ILT-03-2016-0075.

[0198] The present invention will be described in more detail with reference to the drawings. [Brief explanation of the drawing]

[0199] [Figure 1] This is a schematic diagram of a part of the cylinder in a first embodiment of the engine according to the present invention. [Figure 2] Figure 1 is a diagram of one embodiment of the injector shown. [Figure 3] This is a schematic diagram of a circular pipe with a restricted area. [Figure 4] Figure 2 is a schematic diagram showing a further embodiment of the nozzle for the injector shown in Figure 2. [Figure 5]This is a schematic diagram corresponding to Figure 1 of a portion of a cylinder in a further embodiment of the engine according to the present invention. [Figure 6] Figure 5 is a schematic diagram of one embodiment of the injector shown. [Figure 7] Figure 6 is an enlarged cross-sectional view of the inlet valve housing of the injector. [Figure 8] This is a schematic diagram corresponding to Figure 1 of a portion of a cylinder in a further embodiment of the engine according to the present invention. [Figure 9] This is a schematic diagram showing a magnified portion of the front part of the injector. [Figure 10] This graph shows the relationship between time and mass flow rate. [Figure 11] This graph shows the relationship between mass flow rate, cavitation number, and time. [Figure 12] This graph shows the relationship between pressure, time, and cavitation rate. [Figure 13] This is a schematic diagram showing a further embodiment of an injector used in a system according to the present invention, shown in the closed position. [Figure 14] Figure 13 is a schematic diagram of the injector, shown in the open position. [Figure 15] This is the first graph, which shows the limits of the relationship between force and mass. [Figure 16] This is the second graph, which shows the limits of the relationship between force and mass. [Modes for carrying out the invention]

[0200] Figure 1 shows half of a cylinder 1 of a large, low-speed two-stroke engine, such as a marine diesel engine. The cylinder 1 has a cylinder liner 2 inside the cylinder wall 3. Multiple injectors 4 are provided inside the cylinder wall 3 for injecting lubricating oil into the cylinder 1. As shown in the figure, the injectors 4 are distributed along the circumference at the same angular distance from adjacent injectors 4, but this is not strictly necessary. Furthermore, arrangements with injectors displaced in the axial direction are also possible, for example, arrangements where every other injector is displaced toward the top dead center (TDC) of the piston, so the arrangement along the circumference is not mandatory.

[0201] Each injector 4 has a nozzle 5 with a nozzle opening 5', and a fine mist spray 8 of minute droplets 7 is discharged into the cylinder 1 under high pressure from the nozzle opening 5'.

[0202] For example, the nozzle opening 5' has a diameter between 0.1 and 0.8 mm, such as between 0.2 and 0.5 mm, and atomizes the lubricating oil into a fine spray 8 at a pressure of 10-100 bar, for example 25-100 bar, and optionally 30-80 bar or even 50-80 bar, which is in contrast to a high-density jet of lubricating oil. A scavenging swirl 10 within the cylinder 1 transports and presses the spray 8 against the cylinder liner 2 so that uniform distribution of lubricating oil onto the cylinder liner 2 is achieved. This lubrication system is known in the art as the swirl injection principle, or SIP.

[0203] However, in relation to improved lubrication systems, other principles are also being considered, such as injectors that direct a jet of fluid towards the cylinder liner.

[0204] Optionally, the cylinder liner 2 is provided with a free cut 6 to give adequate space for the spray 8 or jet from the injector 4.

[0205] In addition to the lubricating oil supply conduit 9, the injector 4 is connected to the control device 11 by a pressure control conduit 10. The lubricating oil supply conduit 9 is used to supply lubricating oil for injection. The pressure control conduit 10 supplies oil at high pressure to operate the internal pump system inside the injector 4, which will be explained in detail below.

[0206] The pressure in the pressure control conduit 10 is higher than the pressure in the lubricating oil supply conduit 9. Typically, the lubricating oil pressure in the lubricating oil supply conduit 9 is in the range of 1-15 bar, for example, 5-15 bar, and the oil pressure in the pressure control conduit 10 is in the range of 20-100 bar, for example, 30-80 bar, or 50-80 bar if necessary.

[0207] The control device 11 is connected to a supply conduit 12 for receiving lubricating oil from a lubricating oil supply unit 25, which includes an oil pump, and a return conduit 13, which is generally to an oil reservoir, for recirculating the lubricating oil as needed. The lubricating oil pressure in the supply conduit 12 is greater than the pressure in the return conduit 13, for example, at least twice as great.

[0208] The control unit 11 supplies lubricating oil to the injector 4 in precisely time-controlled pulses synchronized with the piston movement in the engine's cylinder 1. For example, for synchronization, the control unit system 11 is electronically connected to a computer 11' by wire or wireless, and the computer 11' controls the components within the control unit 11 for lubrication supply. Potentially, the computer 11' is part of the control unit 11 and is housed, for example, in a single casing along with the other components of the control unit 11. Optionally, the computer monitors parameters relating to the actual state and operation of the engine, such as crankshaft speed, load, and position, where the crankshaft position reveals the piston position in the cylinder.

[0209] Figure 2 shows injector 4.

[0210] The injector 4 comprises an injector housing 4' having an injector base 21 which has a lubricating oil inlet port 4A for receiving lubricating oil from a lubricating oil supply conduit 9 and a pressure port 4B connected to a pressure control conduit 10 to cause the release of lubricating oil by the injector 4.

[0211] The fluid chamber 16, as part of the injector housing 4', holds the nozzle 5 relative to the injector base 21. In the illustrated embodiment, the fluid chamber 16 is provided as a hollow rigid rod. The fluid chamber 16 is sealed against the injector base 21 by an O-ring 22 and is firmly held against the injector base 21. The conduit 16' is provided as a hollow flow path inside the fluid chamber 16, running from the rear to the front of the fluid chamber 16. The conduit 16' communicates with the lubricating oil inlet port 4A and the nozzle 5 via the rear chamber 16A, the first intermediate chamber 16B, the second intermediate chamber 16C, and the front chamber 16D.

[0212] The injector 4 also includes an outlet valve system 15 to regulate the lubricating oil distributed through the nozzle opening 5'. The outlet valve system 15 is opened to release the lubricating oil into the engine cylinder 1 only when the pressure in the outlet valve system 15 exceeds a predetermined pressure. In the embodiment of Figure 2, the outlet valve system 15 is illustrated as part of the nozzle 5, but this is not strictly necessary.

[0213] The outlet valve system 15 includes an outlet check valve 17. In the outlet check valve 17, an outlet valve member 18, exemplified as a ball, is pre-stressed by a spring bias applied by an outlet valve spring 20 toward the outlet valve seat 19. As soon as pressurized lubricating oil is supplied into the pre-chamber 16D, the pre-stressing force of the outlet valve spring 20 is counteracted by the pressure of the lubricating oil, and when the pressure becomes greater than the spring force, the outlet valve member 18 is displaced from its outlet valve seat 19, and the outlet check valve 17 opens to inject the lubricating oil into the cylinder 1 through the nozzle opening 5'.

[0214] As illustrated, the outlet valve spring 20 acts on the outlet valve member 18 in a direction away from the nozzle opening 5'. However, in this configuration, the direction of the force of the outlet valve spring 20 acting on the outlet valve member 18 can be different from the direction relative to the nozzle opening 5', as long as the check outlet valve 17 is closed when the system is idle during the injection phase, which is responsible for supplying lubricating oil to the nozzle opening 5'. Closure of the check outlet valve 17 when idle prevents unintended flow of lubricating oil from the pre-chamber 16D through the nozzle opening 5' into the cylinder 1 during the injection phase.

[0215] The rear chamber 16A communicates with the inlet port 4A to receive lubricating oil from the lubricating oil supply conduit 9. The rear chamber 16A communicates with the first intermediate chamber 16B via the rear passage 23A. The first intermediate chamber 16B communicates with the second intermediate chamber 16C via the intermediate passage 23B, which is a cylindrical opening around the actuator member 28, and this will be explained below. The second intermediate chamber 16C communicates with the front chamber 16D via the front passage 23C.

[0216] For convenience, the term "forward movement" is used for movement toward the nozzle opening 5', and the opposite movement away from the nozzle opening 5' is called "backward movement".

[0217] The front chamber 16D is emptied through the nozzle opening 5' by the forward movement of the reciprocating plunger member 29, which is spring-biased against forward movement by a helical plunger spring 29B in a second intermediate chamber 16C. The plunger member 29 has a flow path inlet 24 leading to the front flow path 23C, which is an internal flow path of the plunger member 29, for example, in the center of the plunger member 29 as shown in the figure. During the forward movement of the plunger member 29, the front flow path 23C is closed by a check plunger valve 26. In the illustrated embodiment, the check plunger valve 26 is exemplified as having a plunger valve ball 26A in a plunger valve seat 26B, and the plunger valve ball 26A is pre-stressed toward the valve seat by a plunger valve spring 26C.

[0218] The forward movement of the plunger member 29 is achieved by the forward movement of the actuator member 28, which presses against the head 29A of the plunger member 29. The actuator member 28 is pre-stressed to the rear by a helical actuator spring 28A located in the first intermediate chamber 16B.

[0219] In this illustrated exemplary embodiment, the actuator member 28 and the plunger member 29 are separate elements, but they can also be combined as a single actuator-plunger, for example, by having the actuator member 28 at one end of the single element and the plunger member 29 at the opposite end.

[0220] The forward movement of the actuator member 28 is achieved by pressurized lubricating oil from the pressure control port 4B, and as the pressurized lubricating oil presses against the rear portion 28B of the actuator member 28 within the pressure chamber 27, they move together.

[0221] The function of the injector 4 is described in more detail below. When pressurized oil, for example, in the pressure range of 20-100 bar, is supplied to the pressure control port 4B, the pressurized oil expands the volume of the pressure chamber 27 by pushing the rear 28B of the actuator member 28 forward and moving the actuator member 28 forward. When the actuator member 28 pushes the head 29A of the plunger member 29, the plunger member 29 moves forward with the actuator member 28 against the force of the actuator springs 28A and 29B. The forward movement of the plunger member acts on the lubricating oil in the front chamber 16D. Since the check valve 26 prevents the lubricating oil in the front chamber 16D from escaping to the rear, the lubricating oil in the front chamber 16D is pressurized to a predetermined pressure limit, which causes the outlet valve system 15, equipped with a check outlet valve 17, to open and release the lubricating oil from the front chamber 16D through the nozzle opening 5' into the cylinder 1.

[0222] At the end of the injection phase, the oil in the pressure control port 4B is discharged, causing the actuator spring 28A and plunger spring 29B to push the actuator member 28 and plunger member 29 away from the nozzle 5. The backward movement of the plunger member 29 reduces the pressure in the front chamber 16D, which in turn closes the check outlet valve 17, drawing lubricating oil from the second intermediate chamber 16C through the front passage 23C into the front chamber 16D, because the plunger check valve 26 is opened by the pressure drop in the front chamber 16D. Thus, the check plunger valve 26 functions as an intake valve, as the pressure drop in the front chamber 16D results in the replenishment of lubricating oil in the front chamber 16D by intake through the check plunger valve 26. During this return movement of the actuator member 28 and the plunger member 29, the lubricating oil in the second intermediate chamber 16C is replenished from the first intermediate chamber 16B, and in turn, the first intermediate chamber 16B is filled with lubricating oil from the rear chamber 16A, which has received lubricating oil through the lubricating oil inlet port 4A.

[0223] To function properly, lubricating oil is supplied to the lubricating oil inlet port 4a from the lubricating oil supply conduit 9 at a constant pressure, and pressurized oil is supplied to the pressure control port 4B intermittently from the pressure control conduit 10 with each injection cycle. The pressure in the pressure control port 4B increases during the injection phase and decreases during the idle state between injection phases.

[0224] When the forward force acting on the actuator member 28 due to the oil pressure in the pressure chamber 27 in the idle state is less than the combined backward force from the actuator spring 28A and the plunger spring 29B, the actuator member 28 and the plunger member 29 are returned to their rearmost possible positions as shown in Figure 2. Thus, the full stroke of the plunger member is achieved by intermittently changing the oil pressure in the pressure control port 4B between the maximum pressure and a lower pressure, for example, the pressure of the lubricating oil in the lubricating oil supply conduit 9 or a lower pressure.

[0225] However, the actuator member 28 and the plunger member 29 can be held offset from their rearmost position by adjusting the pressure in the pressure control port 4B and the pressure chamber 27 to an offset pressure level that creates a force acting on the actuator, and the springs 28A and 29B are kept slightly compressed rather than fully extended during the rearward movement of the actuator member 28 and the plunger member 29. This is possible because the force of the springs 28A and 29B changes with respect to the compression length and generally follows a linear dependence with respect to the displacement of the actuator member from its rearmost position. The offset pressure level is lower than the pressure level required to open the check outlet valve 17 and allow injection.

[0226] In principle, the injector 4 can be supplied with lubricating oil from one lubricating oil supply unit at the inlet port 4A, and can also be supplied with pressurized oil or other pressurized liquid from a completely different supply unit. However, generally, for simplicity and convenience, the pressurized oil at the pressure control port 4B can be supplied from the same supply unit as the lubricating oil at the inlet port 4A, but it can be supplied at high pressure, for example, using a pressure intensifier.

[0227] As is clear from the above embodiment, the lubricating oil supply conduit 9 communicates with the return line 13. This is also indicated by the solid line 9'' in Figure 1, and the solid line 9'' is connected to the lubricating oil supply conduit 9 on its extension. If the control device 11 is an add-on unit, the control device 11 will have at least four conduit connectors.

[0228] However, this is not mandatory. Optionally, the control device 11 may include a return outlet line 34 connected to the return conduit 13, as shown in Figure 3b. In this case, the return conduit 13 communicates directly with the lubricating oil supply conduits 9' and 9. This embodiment is shown in Figure 1 by another dotted line 9', which is connected to the lubricating oil supply conduit 9 on its extension. In this case, the return conduit 13, which lies on the extension of the lubricating oil supply conduits 9' and 9', supplies lubricating oil directly to the lubricating oil inlet port 4A of the injector 4 for injection into the cylinder, bypassing the control device 11.

[0229] FIG. 4 shows a second alternative embodiment of the outlet valve system 15. The general principle of the outlet valve system 15 is the same as that disclosed in International Publication No. WO 2014 / 048438. This reference also presents additional technical details of the injector and an explanation of its function presented herein, but for the sake of convenience, it will not be repeated here. The nozzle opening 5' is provided at the tip of the nozzle 5 for discharging lubricating oil. An outlet valve member 18 is provided inside the cavity 40 of the nozzle 5. The outlet valve member 18 includes a stem 41 and a cylindrical seal head 42 slidably disposed within a cylindrical cavity portion 43 of the nozzle tip 44. The position of the valve member 18 is preloaded rearward by a spring 45 so as to be separated from the nozzle tip 44, and is offset forward by an oil pressure acting on the rear portion 47 of the stem 41 via a flow path 46. The oil pressure acts against the spring force. The nozzle opening 5' is hermetically covered by the seal head 42 that abuts the cylindrical cavity portion 43 at the nozzle tip 44, unless the nozzle member 18 is pushed forward such that the seal head 42 slides past the nozzle opening 5' and lubricating oil flows out through the nozzle opening 5' from the internal cavity 46.

[0230] The following numerical values are non-limiting examples of possible operating pressures. The pressures in the return conduit 13 and the lubricating oil supply conduit 9 are 10 bar. The pressure in the supply conduit 12 is 40 bar. The outlet valve 15 opens at 37 bar so that the lubricating oil is injected at 37 bar. Springs 28A and 29B are configured to push the plunger member 29 and the actuator member 28 fully back to their rear-most positions when the pressure at the pressure control port 4B in the idle state during the injection phase is 10 bar. The pressure valve is adjusted to a sufficiently high pressure, for example 20 bar, to supply the pressure chamber 27 with a pressure of 10 - 30 bar which is much lower than the injection pressure of 37 bar but high enough so that the actuator member 28 does not return fully to its rear-most position but maintains a predetermined distance from the rear-most position. By adjusting the pressure in the range of 10 - 30 bar to adjust this distance, the injection quantity in the front chamber 16D is adjusted, because the smaller the forward movement during the injection phase, the more the plunger member 29 is offset from the rear-most position at the start of the injection phase.

[0231] Optionally, the injection quantity is controlled by a flow meter inserted into the lubricating oil supply conduit 9 for a group of injectors or for each single injector 4. The flow meter measures the flow (mass and / or volume) and is then used to manage that the injector(s) operate(s) properly.

[0232] An injection system comprising an injector 4 and a control device 11 as described above is easy to install and replace. This is a relatively low-cost technical means despite being robust and stable. In particular, the injection quantity is precisely adjustable. Also, the system does not have electrical wiring to or from the injection syringe 4, which makes the system robust against heat, while on the other hand, electrical wiring may have an insulating layer that melts with heat.

[0233] The above-described embodiment is known from International Publication No. WO 2019 / 114905. However, the engine differs in that it is configured to operate within the parameters given in Table 1.

[0234] Here, the values ​​of the six parameters are selected such that the number of cavitations given by equation (8) is less than 1.5, and the combination of parameters shown in Table 1 results in a ratio of the resulting force acting on the needle to the mass of the needle of 50 m / s² with respect to the intended operation. 2 Selected to exceed the limit.

[0235] Figure 5 shows half of a cylinder 1 of a large, low-speed two-stroke engine, such as a marine diesel engine. The cylinder 1 has a cylinder liner 2 inside the cylinder wall 3. Multiple injectors 4 are provided inside the cylinder wall 3 for injecting lubricating oil into the cylinder 1. As shown in the figure, the injectors 4 are distributed along the circumference at the same angular distance from adjacent injectors 4, but this is not strictly necessary. It is also possible to have injectors that are displaced in the axial direction, for example, in which every other injector is displaced toward the top dead center (TDC) of the piston, so the arrangement along the circumference is not mandatory.

[0236] Each injector 4 has a nozzle 5 with a nozzle opening 5', and a fine mist spray 8 is discharged into the cylinder 1 under high pressure from the nozzle opening 5'.

[0237] For example, the nozzle opening 5' has a diameter between 0.1 and 0.8 mm, such as between 0.2 and 0.5 mm, and atomizes the lubricating oil into a fine spray 8 at a pressure of 10-100 bar, for example 25-100 bar, and optionally 30-80 bar or even 50-80 bar, which is in contrast to a high-density jet of lubricating oil. A scavenging swirl 14 within the cylinder 1 transports and presses the spray 8 against the cylinder liner 2 so that uniform distribution of lubricating oil onto the cylinder liner 2 is achieved. This lubrication system is known in the art as the swirl injection principle, or SIP.

[0238] However, in relation to improved lubrication systems, other principles are also being considered, such as injectors that direct a jet of fluid towards the cylinder liner.

[0239] Optionally, the cylinder liner 2 is provided with a free cut 6 to give adequate space for the spray 8 or jet from the injector 4.

[0240] The injector 4 receives lubricating oil from the engine's lubrication supply section 25, which includes a potential lubrication pump that raises the lubricating oil pressure to an appropriate level, for example, from the oil circuit, via a lubrication supply conduit 9, usually via a common lubrication supply conduit 9. For example, the pressure in the lubrication supply conduit 9 is in the range of 25-100 bar, and optionally 30-80 bar, which is a typical pressure range for a SIP injector.

[0241] The injector 4 is equipped with an electrical connector 110' that electrically communicates with the control device 11 via an electrical cable 110. As described above, the injector can also communicate wirelessly with the control device 11. The control device 11 sends electrical control signals to the injector 4 to control the injection of lubricating oil through the nozzle 5 by the injector 4. As shown in the figure, one cable 110 is provided to each injector 4, thereby enabling individual control of injection by each injector. However, it is also possible to provide one electrical cable 110 from the control device 11 to all injectors 4 so that all injectors 4 receive electrical control signals via a single electrical cable and inject simultaneously. Alternatively, one electrical cable 110 is provided from the control device 11 to subgroups of injectors, for example, to subgroups of 2, 3, 4, 5, or 6 injectors, so that the first subgroup is controlled by the control device via the first cable 10 and the second subgroup is controlled via the second cable 110. The number of cables and subgroups is selected according to the preferred configuration.

[0242] The flow meter 35 is connected to the injector 4 and the electrical cable 110 and is positioned to measure the flow rate. This is as described above in relation to Figure 1.

[0243] The electrical control signals from the control device 11 to the injector 4 are supplied as precisely timed pulses synchronized with the piston movement in the engine cylinder 1. For example, for synchronization, the control device system 11 may include a computer 11' or be electronically connected to a computer 11' by wire or wireless, and the computer 11' monitors parameters related to the actual state and operation of the engine, such as crankshaft speed, load, and position, and the crankshaft position reveals the position of the piston in the cylinder.

[0244] The above embodiments are publicly known from International Publication No. 2019 / 114905. However, this engine differs in that it is configured to operate within the parameters given in Table 1.

[0245] Here, the values ​​of the six parameters are selected such that the number of cavitations given by equation (8) is less than 1.5, and the combination of parameters shown in Table 1 results in a ratio of the resulting force acting on the needle to the mass of the needle of 50 m / s² with respect to the intended operation. 2 Selected to exceed the limit.

[0246] Figure 6 shows a main schematic diagram of injector 4. Figure 6 is a schematic diagram including three different views of the illustrated injector: a top view, an end view, and a cross-sectional side view.

[0247] The injector 4 includes a lubricating oil inlet port 112 for receiving lubricating oil from a lubricating oil supply conduit 9. The inlet port 112 is located within an inlet valve housing 121, which includes an inlet valve system 113 communicating with the inlet port 112 to regulate the amount of lubricating oil received from the lubricating oil supply conduit 9 during the lubrication phase. The injector 4 also includes an outlet valve system 115 to regulate the lubricating oil distributed through the nozzle opening 5'. A rigid flow chamber 116 connects the inlet valve system 113 to the outlet valve system 115 to allow lubricating oil to flow to the nozzle 5. In the illustrated embodiment, the flow chamber 116 is provided as a hollow rigid rod. The flow chamber 116 is sealed against the inlet valve housing 121 of the inlet valve system 113 by an O-ring 122 and is firmly held against the inlet valve housing 121 by a flange 123 bolted to the inlet valve housing 121 by a bolt 124.

[0248] Figure 7 shows a magnified view of the inlet valve system.

[0249] Figure 7 shows the inlet valve system 113 in more detail. Inside the inlet valve housing 121, the check inlet valve 125 comprises an inlet valve member 126, which is pre-stressed toward the inlet valve seat 127 by an inlet valve spring 128. The inlet valve member 126 is exemplified as a ball, but it can also function in different shapes such as oval, conical, flattened, or cylindrical. When the inlet valve member 126 is displaced from the inlet valve seat 127 against the force of the inlet valve spring 128, lubricating oil flows from the inlet port 112 along the inlet valve spring 128, through the inlet valve member 126 and the inlet valve seat 127, and into the passage 129 on the opposite side of the inlet valve member 126. The lubricating oil flows from the flow path 129 through the passage 130 and into the hollow section 116' of the flow chamber 116 to flow to the outlet valve system, which has a generalized principle similar to that disclosed in International Publication No. 2014 / 048438. This reference also provides additional technical details of the injector presented herein and a description of its function, but for convenience, it will not be repeated here.

[0250] To displace the inlet valve member 126 (ball), a pushing member 131 exemplified as a push rod is provided reciprocally within the flow passage 129. The pushing member 131 is not fixed to the inlet valve member 126, but is fixed to a reciprocating solenoid plunger 133 driven by a solenoid coil 132. The solenoid plunger 133 is retracted by a plunger spring 134 in an idle state. When the solenoid coil 132 is excited by an electric current, the solenoid plunger 133 moves forward against the force of the plunger spring 134 until it stops against a plunger stop 135. By the movement of the solenoid plunger 133, the pushing member (push rod) 131 pushes the inlet valve member (ball) 126 away from the inlet valve seat 127, allowing lubricating oil to flow into the fluid chamber 116 through the inlet check valve 125.

[0251] In an advantageous embodiment, in an idle state, the pushing member (push rod) 131 is retracted from the inlet valve member (ball) 126 by a predetermined distance, so there is a free movement distance between the pushing member 131 and the inlet valve member 126. When the solenoid coil 132 is excited, the pushing member 131 is accelerated by the solenoid coil 132 over the free movement distance after an initial acceleration and before colliding with the inlet valve member 126. As a result, the inlet valve member 126 is displaced abruptly from the inlet valve seat 127 compared to a situation where the inlet valve member 126 moves together with the pushing member 131 in the initial part of the acceleration. The rapid displacement of the inlet valve member 126 is advantageous for the accurate timing adjustment of the start of lubricating oil injection into the cylinder 1. Optionally, the free movement distance can be adjusted by an adjusting screw 136 at the end of the solenoid plunger 133.

[0252] After the injection phase, by interrupting the current to the solenoid coil 132 which leads to the solenoid plunger 133 being pushed back by the plunger spring 134, the supply of lubricating oil from the inlet port 112 to the nozzle 5 is stopped, and the inlet valve member 126 returns to the tight inlet valve seat 127 for the idle phase of the injection cycle.

[0253] The amount of lubricating oil is controlled by a flow meter, and the control unit / computer allows for adjustment of the lubricating oil amount and calibration of the injector. The amount of lubricating oil is controlled by a flow meter, and the control unit / computer can adjust the amount of lubricating oil so that cavitation occurs in the shortest possible time.

[0254] Figure 8, corresponding to Figure 1, shows a further embodiment relating to half of cylinder 1 of a large, low-speed two-stroke engine, such as a marine diesel engine. This embodiment includes an oil injector. Injector 4 can be an HJ Smartlube 4.0E injector. Injector 4 is connected to a cylinder manifold 203 equipped with a flow meter. The cylinder manifold equipped with the flow meter is connected to a control device 11 via a communication line 211 for flow meter feedback signals. The control device 11 can be a local cylinder control device connected to a central control device 208 via a communication line 210.

[0255] A cylinder manifold 203 equipped with a flow meter is connected to a pump unit 205. The pump unit 205 is connected to a lubricating oil supply unit 25 via a supply conduit 12.

[0256] The pump unit 205 is connected to the cylinder manifold (common rail) via the pressurized oil supply line 214 and supplies lubricating oil to the injector 4. The injector signal bus 212 connects the injector to the control device 11 to calibrate the injector by adjusting the amount of lubricating oil.

[0257] The injector is generally of the type described in International Publication No. 2012 / 126473. The injector can be operated electromechanically, for example, in the form of a solenoid valve or a piezoelectric element.

[0258] Figures 13 and 14 show further embodiments of the injector 4 used in the system according to the present invention, shown in the closed and open positions, respectively.

[0259] The injectors shown in Figures 13 and 14 are electromechanically operated in the form of an electromagnetic on / off valve 213.

[0260] The injector is manufactured as a unit. The on-off valve 213 is an electromechanical valve integrated into the injector 4 for injecting lubricating oil. The electromechanical on-off valve 213 includes a spring-driven push member 231 that acts on the outlet valve member 18. The outlet valve member 18 cooperates with the valve seat.

[0261] The lubricating oil is injected by operating the on-off valve 213 of the injector 4 for injecting the lubricating oil. This operation moves the push member 231 of the on-off valve 4, controlling the injection of lubricating oil.

[0262] Figures 15 and 16 show two graphs illustrating the relationship between the resulting tensile force and the mass of the needle. The resulting tensile force is shown along the x-axis, and the mass of the needle is shown along the y-axis.

[0263] As mentioned above, the goal in achieving cavitation is to increase the flow rate in the valve as quickly as possible. However, there are limits to the combination of maximum mass and small force, and vice versa. The graphs in Figures 15 and 16 are used to illustrate the possible combinations of parameters shown in Table 1.

[0264] The graphs show the same thing. However, Figure 15 shows only the smaller values ​​of force associated with mass, while Figure 16 shows the full range of force from 5 N to 10,000 N (the X-axis is divided logarithmically).

[0265] From Table 1, we can see that when selecting the needle with the maximum mass, the force required to move the needle must be at least 7.5 N in order to satisfy equation (6). However, when using a smaller, and therefore smaller, needle, equation (6) will be satisfied with a smaller force. This relationship is shown by the slope of the graph from 5 N to 7.5 N.

[0266] Therefore, the minimum force in Table 1 is set to 5N. The combination of parameters given in Table 1 results in a ratio of the resulting force acting on the needle to the mass of the needle, with respect to the intended operation, of 50 m / s². 2 You need to select one that exceeds [a certain value].

[0267] Figures 3 and 9-12 are used to illustrate the "Specification / Abstract of Invention" section. [Explanation of symbols]

[0268] 1 cylinder 2 Cylinder Liners 3 Cylinder wall 4 syringe 4' Injector housing 4A Oil injector 4 inlet port 4B Pressure control port of oil injector 4 5 nozzles 5' Nozzle opening 6. Raina's Free Cut 7. Mist spray from single injector 4 8 Swirl spray 9 Lubricating oil supply conduit 10 Pressure control conduit 11 Control device 11' Computer 12 Supply conduit 13 Return conduit 14 Swirl inside the cylinder 15. Outlet valve system of injector 4 16 Flow chamber connecting the inlet valve system to the outlet valve system 16' Hollow section of the fluid chamber 16 16A Posterior chamber 16B First Intermediate Room 16C Second Intermediate Chamber 16D Antechamber 17. Check outlet valve as an example of an outlet ball valve. 18 Outlet valve member exemplified as a ball 19 Outlet valve seat 20 Outlet valve spring 21 Syringe base 22 O-ring at the end of the fluid chamber 16 23A Rear flow path within actuator member 28 connecting rear chamber 16A to first intermediate chamber 16B 23B Intermediate flow path between the first intermediate chamber 16A and the second intermediate chamber 16B 23C Front flow path in plunger 29 between the second intermediate chamber 16B and the front chamber 16D 24 Inlet to the front channel 23C 25 Lubricating oil supply section 26 Check plunger valve 26A Plunger valve ball 26B Plunger valve ball 26A plunger valve seat that receives pre-stress 26C Plunger valve spring that applies pre-stress to the plunger valve ball toward the plunger valve seat 26B 27 Rear 28B pressure chamber 28 Actuator member for the push head 29' of the plunger member 29 28A Actuator spring that acts rearward on the actuator. 28B Rear of actuator member 29 Plunger Member 29A Head of plunger component 29B Plunger spring in the second intermediate chamber 16C 30 toggle valves 30A Toggle Valve Inlet Port 30B Toggle valve outlet port 30C Toggle Valve Return Port 31 Pressure control valve 31A Pressure valve inlet port 31B Pressure valve outlet port 31C Pressure regulator (e.g., spring-driven pressure regulator for the injection phase) 31D Pretensioner for pressure valve 31 32 Toggle Member 32A First toggle closing element of toggle member 32 32B Second toggle closing element of toggle member 32 33 Arrows indicating the reciprocating movement of the toggle member 34 Return outlet line from control device 11 to return conduit 35 Flow meter 112 Lubrication oil inlet port of injector 4 113 Inlet valve system of injector 4 114 Swirl in the cylinder 115 Injector 4 Outlet Valve System 116 Flow chamber connecting the inlet valve system 113 to the outlet valve system 116' Hollow section of the fluid chamber 16 121 Inlet valve housing of inlet valve system 115 122 O-ring at the end of the fluid chamber 116 123 Flange for holding the fluid chamber 124 Bolts for holding the flange 123 and the fluid chamber to the inlet valve housing 121 125 Inlet check valve as an example of an inlet ball valve 126 Inlet valve member exemplified as a ball valve 127 Inlet valve seat 128 Inlet valve spring 129 Flow path of the inlet valve system 130 Passage from flow path 129 to hollow section 116' of flow chamber 16 131 Push member fixed to solenoid plunger, exemplified as a rod 132 Solenoid coil 133 Solenoid plunger in solenoid coil 131 134 Plunger spring 135 Plunger Top 136 Adjustment screw for adjusting the free travel distance 203 Cylinder manifold equipped with a flow meter 205 Pump Unit 208 Central Control System 210 Communication line between local cylinder control unit and central control unit 211 Communication line for flow meter feedback signal 212 Injector signal bus 213 Open / Close Valve 231 Push-in member

Claims

1. A method for lubricating a large, low-speed two-stroke engine comprising a cylinder having a reciprocating piston inside, and a system, wherein the system is Lubrication oil supply unit, Multiple lubricant injectors are distributed along the circumference of the cylinder to inject lubricant into the cylinder at various positions along the circumference during the injection phase, A lubricating oil supply conduit connecting the lubricating oil supply unit and the lubricating oil injector, Equipped with, The aforementioned engine is The system further includes a control device that controls the amount and timing of lubricant injection by at least one of the lubricant injectors. Each of the aforementioned injectors is The aforementioned lubricating oil supply conduit is fluidly connected to an inlet port for receiving lubricating oil from the lubricating oil supply conduit, A nozzle having a nozzle opening extending into the cylinder is configured to inject lubricating oil into the cylinder from the inlet port during the injection phase, Equipped with, The above method applies to the engine, The step of providing an adjustable valve comprising a valve member and a valve seat in the nozzle (5) that opens and closes during the injection cycle to allow lubricating oil to flow from the pressure chamber in the injector to the nozzle opening (5') through the sack hole, The nozzle opening has a cross-sectional area A3, the sac hole has a cross-sectional area A2, and a cross-sectional area A1 is provided between the valve member and the valve seat. The above method involves periodic operation, In the injection phase, pressurized liquid is supplied to the lubricating oil supply conduit. The aforementioned method is configured to operate within the following parameters: Furthermore, the number of cavities Select the values ​​of the six parameters so that the result is as follows: Furthermore, with respect to the intended operation, the ratio of the resulting force acting on the needle to the mass of the needle is 50 m / s². 2 A method for selecting a combination of parameters shown in the table above so as to exceed [a certain value].

2. A large, low-speed two-stroke engine comprising a cylinder having a reciprocating piston inside, and a system, wherein the system is Lubrication oil supply unit, Multiple lubricant injectors are distributed along the circumference of the cylinder to inject lubricant into the cylinder at various positions along the circumference during the injection phase, A lubricating oil supply conduit connecting the lubricating oil supply unit and the lubricating oil injector, Equipped with, The aforementioned engine is A control device that controls the amount and timing of lubricant injection by at least one of the lubricant injectors, The computer to which the control device is connected, Furthermore, Each of the aforementioned injectors is The aforementioned lubricating oil supply conduit is fluidly connected to an inlet port for receiving lubricating oil from the lubricating oil supply conduit, A nozzle having a nozzle opening extending into the cylinder is configured to inject lubricating oil into the cylinder from the inlet port during the injection phase, The nozzle (5) includes an adjustable valve comprising a valve member and a valve seat that opens and closes during the injection cycle to allow lubricating oil to flow from the pressure chamber in the injector to the nozzle opening (5') through the sac hole, Equipped with, The nozzle opening has a cross-sectional area A3, the sac hole has a cross-sectional area A2, and a cross-sectional area A1 is provided between the valve member and the valve seat. The aforementioned engine is used in a periodic manner. The injection phase includes supplying pressurized liquid to the lubricating oil supply conduit, The engine is configured to operate within the following parameters: Furthermore, the values ​​of the six parameters are related to the number of cavities. Selected to be so, Furthermore, with respect to the intended operation, the ratio of the resulting force acting on the needle to the mass of the needle is 50 m / s². 2 A large, low-speed, two-stroke engine in which the combination of parameters shown in the table above is selected to exceed [a certain value].

3. The control device is connected to a computer (11'), or A mobile phone that communicates with the aforementioned control device, A large, low-speed, two-stroke engine according to claim 2, comprising the features described in claim 2.

4. The engine is a large, low-speed two-stroke engine according to claim 2 or 3, comprising a common rail system in which all of the injectors are connected to a common rail.

5. The large, low-speed two-stroke engine according to any one of claims 2 to 4, wherein the lubrication system is selected from a mechanically driven system, a hydraulically driven system, and a common rail system.

6. The engine is a large, low-speed, two-stroke engine according to any one of claims 2 to 5, comprising a hydraulically driven inlet valve system.

7. The engine is a large, low-speed two-stroke engine according to any one of claims 2 to 5, comprising an electrically driven inlet valve system.

8. An injector for a large, low-speed operating two-stroke engine, comprising a cylinder (1) having a reciprocating piston inside and a lubrication system including a control device, The aforementioned injector is A lubricating oil supply conduit is fluidly connected to an inlet port for receiving lubricating oil from the lubricating oil supply conduit, A nozzle configured to inject lubricating oil into the cylinder from the inlet port during the injection phase, and having a nozzle opening extending into the cylinder, The nozzle (5) includes an adjustable valve comprising a valve member and a valve seat that opens and closes during the injection cycle to allow lubricating oil to flow from the pressure chamber in the injector to the nozzle opening (5') through the sac hole, Equipped with, The nozzle opening has a cross-sectional area A3, the sac hole has a cross-sectional area A2, and a cross-sectional area A1 is provided between the valve member and the valve seat. The injector operates periodically, In the injection phase, all of the injectors are configured to supply pressurized liquid via a common rail system connected to the lubricating oil supply conduit. The injector is configured to operate within the following parameter range: Furthermore, the values ​​of the six parameters are related to the number of cavities. Selected to be so, Furthermore, with respect to the intended operation, the ratio of the resulting force acting on the needle to the mass of the needle is 50 m / s². 2 An injector in which a combination of parameters shown in the table above is selected so as to exceed [a certain value].

9. A method for lubricating a large, low-speed two-stroke engine comprising a cylinder having a reciprocating piston inside, and a system, wherein the system is Lubrication oil supply unit (25), Multiple lubricant injectors (4) are distributed along the circumference of the cylinder (1) to inject lubricant into the cylinder (1) at various positions along its circumference during the injection phase, A lubricating oil supply conduit (12) connects the lubricating oil supply unit (25) and the lubricating oil injector (4), Equipped with, The aforementioned engine is The system further includes a control device (11) that controls the amount and timing of lubricant injection by at least one of the lubricant injectors (4), Each of the injectors (4) is an electromechanically operated injector, An inlet port is fluidly connected to the aforementioned lubricating oil supply conduit (12) and receives lubricating oil from the lubricating oil supply conduit (12), The nozzle (5) is configured to inject lubricating oil into the cylinder (1) from the inlet port (4A) during the injection phase, and has a nozzle opening (5') extending into the cylinder (1), Equipped with, The aforementioned method, The step of providing an adjustable valve comprising a valve member and a valve seat for opening and closing to allow the flow of lubricating oil through a sac hole from the pressure chamber in the injector to the nozzle opening (5'), The nozzle opening has a cross-sectional area A3, the sac hole has a cross-sectional area A2, and a cross-sectional area A1 is provided between the valve member and the valve seat. The above method involves periodic operation, In the injection phase, all of the injectors are supplied with pressurized liquid via a common rail system connected to the lubricating oil supply conduit. The injector is configured to operate within the following parameters: Furthermore, the number of cavities Select the values ​​of the six parameters so that the result is as follows: Furthermore, with respect to the intended operation, the ratio of the resulting force acting on the needle to the mass of the needle is 50 m / s². 2 A method for selecting a combination of parameters shown in the table above so as to exceed [a certain value].

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