A method for lubricating a large two-stroke engine that utilizes controlled pressure fluctuations within a common rail.

Abstract

The present invention relates to a method of lubricating a large engine, specifically a marine engine or a power plant engine, using a spray injector, specifically a SIP injector. This method provides a control device configured to vary and control the pressure in the lubricating oil supply conduit within a desired pressure range, and to determine the desired pressure based on the engine load and a measurement of the actual pressure in the lubricating oil supply conduit.

Description

[Technical Field]

[0001] The present invention relates to a large combustion engine, such as a large, low-speed two-stroke engine, and to a method for lubricating such an engine, and to the use thereof.

[0002] More specifically, the present invention relates to a large, low-speed two-stroke engine comprising a cylinder having a reciprocating piston and a lubrication system, wherein the lubrication system is A lubrication oil supply unit including a lubrication oil pump that increases the lubrication oil pressure to the lubrication oil pressure, which is the typical pressure range for a spray injector, 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 connecting the lubricating oil supply unit and the lubricating oil injector, 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 the lubricating oil supply conduit and has an inlet port for receiving lubricating oil from the lubricating oil supply conduit, During the injection phase, the device is configured to inject lubricating oil into the cylinder from an inlet port and includes a nozzle having a nozzle opening that extends into the cylinder.

[0003] Preferably, each injector is provided with an adjustable valve in the nozzle that opens and closes to allow lubricating oil to flow into the nozzle opening during the injection phase.

[0004] The method relates to the lubrication of such a large, low-speed two-stroke engine. More specifically, it relates to a method for lubricating a large, low-speed two-stroke engine comprising a cylinder with a reciprocating piston inside, and a system, wherein the system is A lubrication oil supply unit including a lubrication oil pump, 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 connecting the lubricating oil supply unit and the lubricating oil injector, 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 having a nozzle opening extending into the cylinder, configured to inject lubricating oil into the cylinder from an inlet port during the injection phase, Equipped with, This method, The lubrication hydraulic pressure is increased to the lubricating oil pressure, which is the typical pressure range for a spray injector, and then, with periodic operation, In the injection phase, pressurized liquid is supplied to the inlet port of the injector, and force is applied to the valve, causing the valve body to move within the injector. When the pressure rises above a predetermined limit, a predetermined volume of lubricating oil is pumped from the nozzle opening into the cylinder.

[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 (11') to which the control device is connected, or A mobile phone that communicates with the control device. It can provide even more.

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

[0008] Furthermore, it should be noted that "extending into the cylinder" means that although the injector is embedded in the cylinder wall to ensure the free movement of the piston, it extends through the cylinder wall. [Background technology]

[0009] 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.

[0010] For lubrication of large, low-speed, two-stroke marine diesel engines, several different systems exist, including the injection of lubricating oil onto the cylinder liner or the injection of oil quills into the piston rings.

[0011] Lubrication can be performed as a jet injection, which is the injection of lubricating oil into the cylinder liner or piston ring pack as a small jet. This is also known as pulse lubrication.

[0012] Alternatively, lubrication can be performed as spray injection, where lubricating oil is injected into the combustion chamber under high pressure. This injects a fine mist of lubricating oil into the cylinder, preferably into the combustion chamber. The lubricating oil is supplied as a mist of atomized oil droplets. The injector for spray injection is called a spray injector. A specific type of spray injection is SIP injection. The injector for SIP injection is called a SIP injector. SIP injection will be discussed in more detail below.

[0013] An example of a lubricating oil injector for a marine engine is disclosed in European Patent No. 1767751, in which a check valve is used to provide a path for lubricating oil to a nozzle passage inside a cylinder liner. The check valve comprises a reciprocating spring-pressed ball on a valve seat just upstream of the nozzle passage, the ball being displaced by the pressurized lubricating oil. Ball valves are a traditional technical means based on principles dating back to the early 20th century, as disclosed, for example, in British Patent No. 214922 of 1923.

[0014] A relatively new alternative lubrication method compared to conventional lubrication is commercially known as the swirl injection principle (SIP). This is based on injecting a spray of atomized oil droplets of lubricating oil into the scavenging swirl inside the cylinder. The spiral, upward swirl draws the lubricating oil toward the top dead center (TDC) of the cylinder, resulting in a thin, uniform layer being pressed outward against the cylinder wall. This is described in detail in International Publications 2010 / 149162 and 2016 / 173601. The injector comprises an injector housing with a reciprocating valve member, typically a valve needle, located inside. The valve member, such as the needle tip, closes and opens the path of lubricating oil to the nozzle opening according to precise time adjustments. In current SIP systems, spraying with atomized oil droplets is typically achieved at a pressure of 35-40 bar. By comparison, this is considerably higher than the hydraulic pressures 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. In addition, 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 away from the nozzle opening, causing the highly pressurized oil to be released from there as atomized droplets. The release of the oil leads to a decrease in the oil pressure against the valve member, which returns to its starting position and remains there until the next lubrication cycle, when the high-pressure lubricating oil is again supplied to the lubricating oil injector.

[0015] 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 out 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.

[0016] The optimization of the spray in SIP lubrication is steadily progressing. However, lubricating injectors have similarities with fuel injectors but also show different behaviors and effects when compared. This is mainly due to the 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.

[0017] In the case of SIP injection, in addition to the goal of minimizing oil consumption, precisely controlled timing adjustment is essential. For this reason, the SIP system is specially designed for a rapid reaction response during the injection cycle.

[0018] Spray injection does not need to be controlled as precisely as SIP injection. In spray injection, it is not necessary to use scavenging swirl in the cylinder to distribute the atomized oil droplets of lubricating oil onto the liner of the cylinder.

[0019] 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, pressure, and temperature of the lubricating oil, and mechanical wear of the components in the lubrication system, a method is required to automatically ensure that the system supplies the desired amount of lubricating oil, and further ensure that most of the supplied lubricating oil is supplied in the form of a spray.

[0020] The HJL Smartlube 4.0 system is a unique combination of compact design and advanced functionality. This system features one or two high-pressure units for supplying lubricating oil to the injectors. Each high-pressure unit includes a pump, which is connected to all injectors in the engine via a common rail. The cylinder manifold connects all injectors in the cylinders to the common rail. In this system, each injector is independently controlled by a control signal received from the control unit.

[0021] One important factor for atomization is cavitation within the nozzle, which is the formation of vapor cavities in the liquid due to evaporation. Cavitation within the nozzle causes significant turbulence in the liquid flow and destabilizes the jet, 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.

[0022] A detailed description of the formation of vapor cavities is disclosed in the applicant's International Publication No. 2018 / 215645. The disclosures in International Publication No. 2018 / 215645 are incorporated herein by reference instead of repeating the description of cavitation.

[0023] 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.

[0024] 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 spray injection, particularly in SIP injection.

[0025] 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 spray injection, e.g., IP injection). The parameters for spray injection, specifically SIP injection, are set outside the range where cavitation occurs.

[0026] 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 spray injection, and more specifically, SIP lubrication.

[0027] 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.

[0028] Further research leading to the present invention has shown that controlling the pressure of the lubricating oil supplied via the common rail is beneficial. It has been shown that controlling the pressure within the common rail affects how lubricating oil droplets move within the scavenging swirl of a marine two-stroke engine.

[0029] It has been shown that the distribution of oil droplets on the cylinder wall depends on the engine load.

[0030] Studies have shown that at low loads, smaller oil droplets do not reach the cylinder wall surface. Furthermore, studies have shown that as the load increases, the size of the small oil droplets that do not reach the cylinder wall also increases. This is thought to be due to the increased swirl velocity and density of the air. Consequently, more oil droplets are "grabbed," leading to greater droplet breakdown and the capture of even more oil from the air.

[0031] It has also been shown that common rail pressure affects where oil droplets end up on the cylinder wall.

[0032] It has been shown that controlling the pressure of the lubricating oil supplied through the common rail is important in order to influence the size of the oil droplets in the spray injected into the cylinder, and consequently, the distribution of lubricating oil on the cylinder wall.

[0033] European Publication No. 0049603 describes a system for supplying lubricating oil to a low-speed ignition mechanism. However, this document instructs the use of time-controlled lubricating oil positioned between piston rings. Furthermore, this document only concerns controlling the amount of lubricating oil based on the power generated. It does not mention controlling and changing the pressure according to the engine load. Moreover, this document does not specify the use of pressure within the range of SIP injection.

[0034] International Publication No. 2023 / 088526 describes a large internal combustion engine and the method described in the preface. This system teaches the use of lubricating oil at pressures within the SIP injection range. However, this document does not teach a control device configured to control and change the pressure in the lubricating oil supply conduit.

[0035] No prior art documents disclose a method or system for controlling the pressure within a common rail to influence the location where oil droplets land on the cylinder wall. [Prior art documents] [Patent Documents]

[0036] [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 [Patent Document 12] European Publication No. 0049603 [Patent Document 13] International Publication No. 2023 / 088526 [Overview of the Initiative] [Problems that the invention aims to solve]

[0037] An object of the present invention is to provide an improvement over the prior art system to achieve the desired effect in which the majority of the lubricating oil collides with the surface of the cylinder wall by adjusting the pressure in a lubricating oil supply conduit, which is preferably a common rail.

[0038] In particular, the objective is to improve spray lubrication using spray injectors in common rail systems of large combustion engines, such as large, low-speed two-stroke engines. Furthermore, the objective is to improve SIP lubrication using spray injectors in the form of SIP injectors.

[0039] A further object of the present invention is to provide a system that controls the degree of atomization, and therefore the size of lubricating oil droplets in the spray, using pressure fluctuations.

[0040] 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]

[0041] These objectives are achieved by a large combustion engine, as described in the introduction and defined in the prerequisite section of claim 1, for example, a low-speed two-stroke engine, which is characterized in that the control device is configured to control and vary the pressure in the lubrication oil supply conduit within a range of desired pressures, preferably from 10 bar to 400 bar, preferably from 25 bar to 100 bar, and optionally from 30 bar to 80 bar.

[0042] Furthermore, these objectives are also achieved by the method according to the present invention for lubricating a large combustion engine, as described in the introduction and defined in the prerequisite section of claim 7, the method being unique in that it includes the step of using a control device to vary and control the pressure in a lubricating oil supply conduit within a desired pressure range of 10 bar to 400 bar, preferably 25 bar to 100 bar, and optionally 30 bar to 80 bar.

[0043] Preferably, the lubricating oil supply conduit is a common rail.

[0044] Preferably, the lubricating oil supply unit is a high-pressure unit. Preferably, the high-pressure unit includes a pump.

[0045] Preferably, the lubrication oil supply system is an HJL Smartlube 4.0 system.

[0046] Furthermore, the present invention is also applicable to engine lubrication principles that are modified in that multiple lubrication supply conduits are replaced by a single common lubrication supply conduit. In this case, the high-pressure unit supplies 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 common lubrication supply conduit.

[0047] A return line is optionally provided to allow the lubricating oil to flow back from the injector.

[0048] A large two-stroke engine comprises a cylinder with a reciprocating piston inside, and multiple lubrication injectors distributed along the circumference of the cylinder for injecting lubricating oil 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 for a power plant. Typically, the engine burns fuel oil.

[0049] 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.

[0050] 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.

[0051] In a spray injector, such as 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.

[0052] By changing the pressure, the degree of atomization and therefore the size of the lubricating oil droplets in the spray can be controlled. This is important for controlling the lubricating oil mist and controlling the position where the lubricating oil droplets will strike the cylinder liner under various engine operating conditions.

[0053] A control device is provided. The control device comprises a computer or is connected to a computer electronically or wirelessly. Advantageously, the computer is configured to monitor parameters relating to the actual load and movement of the engine. Working in cooperation with the computer, and based on these parameters, the control device controls the amount and timing of lubricant injection by the injector during the injection phase. In advantageous embodiments, the control device is also configured to control the pressure of the lubricant in the common rail and optionally the temperature of the lubricant.

[0054] It is preferable that cavitation is established in the lubricating oil within the injector. Research leading to the present invention has shown that cavitation is beneficial for the formation of the lubricating oil spray. Surprisingly, it has been found that it is possible to improve the distribution of oil droplets in the spray for lubricating the cylinder wall.

[0055] For spray generation to occur, the primary pressure drop must be above the last hole of the nozzle. This can be explained by the orifice equation [1] shown in equation (1) below. In JPEG2026521502000002.jpg14150 Equation (1), Q is the volumetric flow rate, C d ρ is the discharge coefficient, A0 is the area of ​​the restricted section, 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.

[0056] For a lubricating oil to cause cavitation, the cavitation count must be 1 or less. The cavitation count is shown in equation (2). In JPEG2026521502000003.jpg13150 formula (2), 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 (2) 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 JPEG2026521502000004.jpg6150 in mind, we can see from equation (1) that the number of cavitations decreases as ΔP increases.

[0057] The following describes a numerical simulation conducted to demonstrate the effects obtained by the present invention. When lubricating oil is injected during scavenging in a marine two-stroke engine, the oil droplets are affected by the scavenging. The movement of these oil droplets is governed by the Stokes number shown in equation (3). JPEG2026521502000005.jpg9150

[0058] In equation (3), t is the time constant for the exponential decay of the particle's velocity due to drag, U is the particle's velocity, and l is the characteristic length of the particle's shape, which is the diameter in the case of a sphere. From the Stokes number, it can be seen that particles with a small Stokes number follow the fluid's motion well. In the case of an oil droplet during scavenging, the droplet will follow the motion of the scavenging. Particles with a large Stokes number are governed by their own inertia and follow their initial trajectory with little influence from the scavenging flow.

[0059] The extent to which oil droplets are affected by the scavenging flow will influence their trajectory, ultimately affecting where they end up within the cylinder.

[0060] Since it is not easy to analytically determine the time constant of the Stokes number, we simulate the oil droplets in the scavenging flow to determine the extent to which the oil droplets are affected by the scavenging flow.

[0061] This invention investigates, based on simulations, how the cylinder oil supply rate can be reduced. The model development is based solely on the common rail cylinder lubrication system for large two-stroke marine diesel engines described in "N. Kristensen, 2019, "HJ Common Rail Lubrication System," CIMAC Congress."

[0062] This uses an electromagnetically operated valve to atomize the lubricating oil. The injector operates on the swirl injection principle, as described, for example, in "S. Lauritsen, J. Dragsted, and B. Buchholz, 2001, "Swirl Injection Lubrication - a New Technology To Obtain Low Cylinder Oil Consumption Without Sacrificing Wear Rates," CIMAC congress pp.921-932," where the oil is injected upward along the cylinder liner before the piston passes through in the compression stroke. Therefore, the objective of this study is to develop and validate a model for investigating the swirl injection principle.

[0063] To validate a simulation-based study, the following numerical framework is necessary.

[0064] The simulation performed is a computational fluid dynamics model. The governing equations for the problem are continuity (4), momentum (5), energy (6), and species (7). JPEG2026521502000006.jpg52150 Here, The filename is JPEG2026521502000007.jpg14150.

[0065] In equation 3-7, ρ is density, U is the velocity vector, p is pressure, g is the acceleration due to gravity, h is enthalpy, q is the heat flux, and Y i Species mass fraction, μ eff ν is the effective kinematic viscosity coefficient, ν is the kinematic viscosity ratio, I is the identity matrix, and τ is the shear stress tensor. The turbulent flow model used is disclosed in "Launder B and Spalding D. The numerical computation of turbulent flows. Computer Methods in Applied Mechanics and Engineering 1974; 3(2): 269-289. DOI:10.1016 / 0045-7825(74)90029-2". The file is JPEG2026521502000008.jpg11150 and is governed by the following equation: JPEG2026521502000009.jpg15150 JPEG2026521502000010.jpg17150 Here, k is the turbulent kinetic energy, ε is the turbulent kinetic energy dissipation rate, P is the turbulent kinetic energy generation rate, D is the effective diffusivity rate, and C is a different model constant. The simulation is run as a transient Reynolds-averaged Navier-Stokes (URANS) simulation with a maximum Courant-Friedrich-Lévy condition (CFL) number less than 1.

[0066] The scavenging flow was determined by solving the system of equations, and its accuracy was compared with results from the literature. These results are shown in Figures 3 and 9.

[0067] The comparison between the experimental data of the above two figures and the literature is based on a certain study, namely "Nemati A, Cai J, Vincent M et al. Numerical Study of the Scavenging Process in a Large Two-Stroke Marine Engine Using URANS and LES Turbulence Models. SAE International 2020; 1- DOI:10.4271 / 2020-01-2012". As can be seen from Figures 3 and 9, the accuracy of the scavenging flow needs to be sufficient to determine the influence of the scavenging flow on the particle trajectory.

[0068] In the simulation, particles are injected into the scavenging flow, and their movement is determined by Newton's second law. JPEG2026521502000011.jpg12150Here, F is the sum of the forces acting on the particle, m is the mass of the particle, and α is the acceleration. Describing Equation (11) in detail, JPEG2026521502000012.jpg16150we get, where the subscript p refers to the particle, U is the velocity, t is the time, m is the mass, and F is the force.

[0069] The buoyancy force is calculated as in Equation (13), JPEG2026521502000013.jpg11150where ρ p is the density of the particle, ρ f is the scavenging density, g is the acceleration due to gravity, and V p is the volume of the particle. The drag force is calculated as in Equation (14), JPEG2026521502000014.jpg17 / 170where C D is the drag coefficient, U is the flow velocity, U p is the particle velocity, and A p is the cross-sectional area of the particle in the direction of the flow. Since Equation (12) is solved for each time step of the simulation and each particle, a small CFL number will give a good approximation of the exponential decay of the particle velocity due to the drag force.

[0070] The initial velocity of the particles entering the cylinder was experimentally determined using Bosch's injection rate method ("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"). Figure 10 shows these measurement results.

[0071] As can be seen from Figure 10, the mass flow rate does not increase instantaneously even when the valve opens. 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.

[0072] The particle velocity is, The calculation is performed using JPEG2026521502000015.jpg11150, derived from the mass flow rate. Simulations were performed with two different initial oil droplet size distributions shown in Figures 11 and 12.

[0073] These two distributions have quite different shapes, but the key difference is how small the oil droplets each contains.

[0074] The samples in Figure 12 consist mostly of very small oil droplets, while those in Figure 11 follow a normal distribution, but the median is approximately 150 μm, which is considerably larger than that of Figure 12.

[0075] These two oil droplet size distributions are used as input to a simulation model of scavenging within a cylinder. This simulation model can predict what percentage of the oil droplets will collide with the cylinder walls.

[0076] When using the distribution shown in Figure 12, approximately 42% of the injected mass reaches the cylinder wall, while when using the distribution shown in Figure 11, approximately 99.5% of the injected mass reaches the cylinder wall. Therefore, the oil droplet size distribution significantly affects how much of the lubricating oil reaches the wall.

[0077] In connection with the development of a mathematical model of lubricating oil spray during scavenging, it was found that at low simulated engine loads, the smallest oil droplets in the spray do not collide with the cylinder wall at all. This is also true at high loads, however, the limit of oil droplets reaching the cylinder wall moves with the load. This is shown in Figures 13 and 14, where Figure 13 shows the distribution and Figure 14 shows the results using this distribution.

[0078] It has been observed that the minimum size required for oil droplets to avoid impacting the cylinder wall changes with load. The actual distribution of oil droplets formed in the engine depends not only on scavenging but also largely on the pressure inside the nozzle. An example of oil droplet distribution is shown in Figure 13. Figure 13 is an example of oil droplet distribution, and Figure 14 is an example of oil droplets that did not reach the cylinder wall. The blue particles are oil droplets during scavenging that did not reach the cylinder wall.

[0079] It is common knowledge that the size of an oil droplet is inversely proportional to the pressure behind the needle in the injector. Therefore, it would be advantageous to change the pressure in the common rail when the engine load changes, thereby increasing the adhesion of oil droplets to the cylinder wall.

[0080] The difference in distribution between Figures 11 and 12 indicates that the simulation shows that smaller oil droplets closely follow the streamlines and therefore do not reach the wall. Larger oil droplets that initially trace a trajectory toward the cylinder wall are affected, but not to the extent that they do not collide with the wall.

[0081] This indicates that for spraying technology, and more specifically SIP technology, to function efficiently, the Stokes number of oil droplets must not be low.

[0082] To influence the Stokes number of an oil droplet, it is first necessary to affect the inertia of the oil droplet or to change the flow within the cylinder. The flow within the cylinder changes in terms of velocity and density with changes in engine load, as shown in equation (14).

[0083] As demonstrated in the study "Chaker, Mustapha. (2007). Key Parameters for the Performance of Impaction-Pin Nozzles Used in Inlet Fogging of Gas Turbine Engines. Journal of Engineering for Gas Turbines and Power-transactions of The Asme - J ENG GAS TURB POWER-T ASME. 129. 10.1115 / 1.2364006", the injection pressure is inversely proportional to the droplet size of the injected fluid, and this also applies to the velocity of the bulk fluid.

[0084] The injection pressure can be used to influence the initial Stokes number of the oil droplet, as simulations show.

[0085] Therefore, experiments and studies have shown that controlling the injection pressure helps optimize the system's efficiency in response to changes in engine load.

[0086] In fact, the method according to the present invention is used to control common rail pressure with predetermined parameters. TIFF2026521502000016.tif23155

[0087] For an injector to function quickly for its intended purpose, it is important that the injector can operate within a given parameter span.

[0088] 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 A lubrication oil supply unit including a high-pressure pump, 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 connecting the lubricating oil supply unit and the lubricating oil injector, Equipped with, The engine is, A control device for controlling the amount and timing of lubricant injection by at least one lubricant injector, The control device is connected to a computer or mobile phone, 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 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 is provided to open and close during the injection phase to allow lubricating oil to flow into the nozzle opening. Equipped with, The method involves periodic operation. In the injection phase, pressurized liquid is supplied to the inlet port of the injector, force is applied to the valve, the valve body is moved within the injector by that force, and when the pressure rises above a predetermined limit, a predetermined volume of lubricating oil is pumped from the nozzle opening into the cylinder. The step of providing at least one pressure gauge for measuring the pressure in a lubricating oil supply conduit, The steps include measuring the pressure in the lubricating oil supply conduit using at least one pressure gauge, In a control device, in order to obtain a desired pressure in the lubrication oil supply conduit while taking into account the actual engine load, the measured pressure is converted into a control signal that is transferred to the lubrication oil supply unit. Includes.

[0089] Alternatively, the method involves periodic operation. In the injection phase, pressurized liquid is supplied to the inlet port of the injector, force is applied to the valve, the valve body is moved within the injector by that force, and when the pressure rises above a predetermined limit, a predetermined volume of lubricating oil is pumped from the nozzle opening into the cylinder. After the injection phase, the valve body is retracted by discharging pressurized liquid from the injector. During the retraction phase, the step of refilling the pressure chamber in the injector with lubricating oil for the subsequent injection phase, It can include...

[0090] The control signal for lubricant supply is, - The output of the high-pressure pump can be adjusted to obtain the desired pressure in the lubricating oil supply conduit. In this case, the rotational speed of the pump is adjusted. Or, - It can be installed in a high-pressure pump and used to adjust a valve connecting the high-pressure pump to a lubricating oil supply conduit. In this case, the output of the high-pressure pump is kept constant, and the adjustment of the valve is used to adjust the pressure in the lubricating oil supply conduit to a desired pressure. Preferably, the valve is connected to the positive and negative pressure sides of the high-pressure pump. Thus, the valve can release pressure because it is connected to the negative pressure side of the high-pressure pump or to the return line to the lubricating oil supply.

[0091] In this invention, the desired effect can be achieved by controlling the pressure in the lubricating oil supply conduit, thereby adjusting the pressure in the common rail to affect the size of the oil droplets, and causing the majority of the lubricating oil to collide with the surface of the cylinder wall.

[0092] The control unit controls and adjusts the pressure in the lubricating oil supply conduit based on measured engine load and the actual pressure in the lubricating oil supply conduit.

[0093] Furthermore, the control device can control an adjustable valve to adjust the stroke length of a valve member in the form of a plunger, thereby allowing the amount of lubricating oil to be variably adjusted during the injection phase by the stroke length adjustment mechanism. Adjustment is achieved when the plunger has not fully retracted to its maximum retraction position. Since the plunger stroke is always in the same position, for example, the same forwardmost position, the stroke length can be adjusted by changing the retracted position of the plunger after retraction.

[0094] The control device can be integrated into the injector, or connected to the injector and flow meter via wired or wireless connections.

[0095] The control device can also be configured to control the type of lubricant used.

[0096] In some embodiments, the plunger's maximum retractable position is the rearmost 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 position. 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.

[0097] 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, An outlet valve system in the nozzle 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. moreover, 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 that 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, Equipped with, 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] This engine and method comprises a hydraulically driven inlet valve system known from International Publication No. 2019 / 114905. However, this engine differs in that it is equipped with a pressure gauge, which is used to measure the pressure in the lubricating oil supply conduit.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] An engine equipped with an electrically driven inlet valve system can be operated according to a method that includes the steps of: sending an electrical control signal from a control device to the electrically driven inlet valve system to initiate the injection phase; 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 in the conduit by the flow of lubricating oil into the conduit; opening the outlet valve system by the pressure increase to allow lubricating oil to flow from the conduit to a nozzle opening; injecting lubricating oil into the cylinder through the nozzle opening; and at the end of the injection phase, changing the electrical 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.

[0109] This engine and method comprises an electrically driven inlet valve system known from International Publication No. 2019 / 114905.

[0110] In a further embodiment, the engine is unique in that the lubrication system can be selected from a mechanically driven system, a hydraulically driven system, and a common rail system.

[0111] The principle of the present invention is adaptable and can be used in various lubrication systems.

[0112] In a further embodiment, this engine is unique in that a pressure gauge is provided in a lubricating oil supply conduit connected to an injector.

[0113] This allows the pressure actually flowing into the injector to be measured. The pressure gauge can be placed directly in front of the inlet port of a single injector, or alternatively, in a common supply conduit for multiple injectors, such as each injector in a single cylinder.

[0114] 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.

[0115] In some embodiments, this method includes storing the regulatory value in a database within the control unit.

[0116] The method and engine according to the present invention are particularly suitable for spray injection, and more specifically SIP injection, into the cylinders of large marine engines or power plant combustion engines at lubrication oil pressures ranging from 10 bar to 400 bar, preferably from 25 bar to 100 bar. The method is also suitable for lubrication combining spray injection, and more specifically SIP injection, with injection into ring packs. Injection into ring packs can be in the form of lubricating oil spray or a compact lubricating oil jet.

[0117] In particular, the method and engine according to the present invention are particularly suitable for use in SIP injection using an injector of the type commonly described in International Publication No. 2012 / 126473 and also known as the Hans Jensen Lubricators E-sip injector.

[0118] definition The term "adjust" refers to a situation where the amount of lubricating oil is changed during engine operation to match the desired amount.

[0119] The term "adjust" refers to the situation where the amount of lubricating oil is changed during the calibration of an injector.

[0120] 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, 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.

[0121] 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.

[0122] The term "idle phase" is used to refer to the time between injection phases.

[0123] The term "idle state" is used to refer to the state of a component during the idle phase.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] The term "pressurized lubricant" is used to refer to lubricant supplied at a pressure high enough to be injected into a cylinder as a jet or spray. The latter 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 spray injection, specifically SIP injection, the pressure is typically higher, for example, above 25 bar.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] The injector is configured to suit the type of lubricant being 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.

[0134] The engine is further equipped with a control system. This control system is configured to control the amount and timing of lubricating oil injection through multiple injectors. The injection frequency can also be optionally controlled by the control system. For accurate injection, it is advantageous for the control system to be electronically connected to a computer, or to include a computer, in which case the computer monitors parameters related to the engine's actual load and operation. Such parameters help in optimizing injection control.

[0135] Optionally, the control unit is offered as an add-on system for upgrading existing engines. A further advantageous option is the connection of 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. Electronic data connectivity is optionally wired, wireless, or a combination thereof.

[0136] 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.

[0137] The injector has a lubricating oil channel from the lubricating oil inlet to at least one nozzle for the lubricating oil to flow into the cylinder through at least one nozzle from the lubricating oil inlet.

[0138] 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.

[0139] 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 2012 / 126480. In some embodiments, the injector comprises a single nozzle having a single nozzle opening.

[0140] 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.

[0141] 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.

[0142] Examples of pressure control In certain embodiments, the engine includes a lubricating oil supply conduit containing lubricating oil at a desired pressure and connected to the E sip injector described above.

[0143] The injector features an integrated open / close valve, preferably a solenoid valve, and has only one common supply line for pressurized lubricating oil (no return line is needed), significantly simplifying both piping and cable routing, and ensuring that injection occurs in proportion to the time the open / close solenoid valve is open. Preferably, there is a separate local control box used to open / close the injector based on signals from the ship's engine / control unit.

[0144] Electromechanically controlled injectors designed for cylinder lubrication in large diesel engines offer advantages over prior art lubrication systems. Systematically, the amount and timing of lubricating oil can be individually controlled.

[0145] This functionality relies solely on a control box that can control each individual injector individually or collectively in terms of timing and opening time. This can be done independently of other open / close valves and is limited only by the speed at which the open / close valves within the injectors can perform their open / close cycles.

[0146] The measured flow rate is used to control the supply rate relative to the intended amount. A deviation of a predetermined magnitude over a given period allows the associated local control box to correct the opening time of the associated injector(s) solenoid valve(s).

[0147] In another embodiment, the engine comprises a lubricating oil supply conduit containing lubricating oil at a first pressure and a pressure control conduit containing pressurized liquid at a pressure higher than the first pressure. In such an example, the injector comprises an internally hydraulically driven pump system, where pressurized liquid 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 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 pressurized liquid from there during the injection phase.

[0148] 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.

[0149] 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.

[0150] The pump system includes a reciprocating hydraulic actuator-plunger that contacts the pressure chamber and is prestressed by a spring load from an actuator-plunger spring, the reciprocating hydraulic actuator-plunger being 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 through a check valve and nozzle opening.

[0151] 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. Various selections of the lubricating oil to be injected, its amount, and timing, controlled by the control device, allow for a variety of injection sequences, 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.

[0152] Regarding various injections, the choice of lubricant(s), including additives, can be changed depending on the situation.

[0153] 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.

[0154] In certain embodiments, 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 a control device.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] 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.

[0178] 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.

[0179] System advantages The system described in this specification has many advantages.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] 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.

[0187] 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 oil droplets, also known as oil mist.

[0188] The atomization of lubricating oil droplets is crucial in spray lubrication. Such atomization is particularly important 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 atomized oil droplets are carried toward TDC by the swirl motion of the scavenging chamber toward TDC, thus diffusing and distributing them across the cylinder walls. 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 an inaccuracy of a few milliseconds can negatively affect the injection profile, hence the need for high precision, such as 0.1 milliseconds, as mentioned above.

[0189] 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.

[0190] The motion of an oil droplet is governed by the relationship between its momentum and the forces acting on it. The momentum of an oil droplet is controlled by its velocity and mass. JPEG2026521502000017.jpg11150 Here, P is momentum, m is the mass of the oil droplet, and U is the velocity of the oil droplet.

[0191] The force (F) that affects the oil droplet is described as follows: JPEG2026521502000018.jpg11150 The two most important forces are buoyancy JPEG2026521502000019.jpg11150 and, The image is JPEG2026521502000020.jpg16150. Here, ρ is density, g is gravitational acceleration, V is volume, and C D is the drag coefficient, U is the velocity, and A is the cross-sectional area of ​​the oil droplet. The subscript f represents the fluid around the oil droplet, and the subscript p represents the oil droplet. The oil droplet obeys Newton's second law. JPEG2026521502000021.jpg16150

[0192] From equation (15), it can be seen that the velocity of the oil droplet changes due to the influence of force, and therefore its momentum also changes. When the engine load of a ship changes, both buoyancy and drag ρ f This changes. When the engine load changes, the thrust U also changes. This shifts the relationship between the force acting on the oil droplet and the momentum of the oil droplet, and therefore changes the way the oil droplet moves. See equation (15).

[0193] To obtain a favorable relationship between the momentum of an oil droplet and the force acting on it, it is necessary to influence the momentum of the oil droplet. this is, - The temperature (i.e., viscosity) of the lubricating oil; - Pressure inside the common rail; - Geometric conditions of the nozzle, for example, rounding the corners of the entrance from the sac hole to the spray hole; This can be done by changing one of the following.

[0194] In addition, from equation (15) above, it can be seen that if the initial velocity of the oil droplets coming out of the nozzle is the same and they are nearly round, smaller oil droplets will be more affected by the flushing air in the cylinder than larger oil droplets.

[0195] In addition to influencing the momentum of the oil droplets, it is also possible to control the position at which the oil droplets collide with the cylinder wall by changing the injection angle within the cylinder.

[0196] This information can influence how oil droplets move during scavenging, ultimately affecting where they collide with the cylinder wall.

[0197] The pressure fluctuations measured by the pressure gauge inside the injector are used to calculate the volumetric flow rate through the nozzle in experimental tests.

[0198] These experimental tests demonstrate a good agreement between the volume calculated from pressure measurements and the volume actually injected.

[0199] The injection rate of SIP lubrication for cylinder lubrication, as tested using Bosch's injection rate method, yields the following results: - The mass flow rate increases in approximately 1 millisecond until cavitation within the nozzle begins to choke the flow. Once choke begins, the cavitation becomes strong enough to atomize the lubricating oil. As a result, spray generation is faster, which is an advantage when using the SIP principle 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 supply 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 lubricating oil. [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]

[0200] The ability to accurately inject lubricating oil with precision of several milligrams or more per injection, along with the rapid rise and fall of mass flow rate, opens up new possibilities for lubrication strategies. For example, this includes the ability to inject multiple times during a piston stroke, supplying the required amount each time.

[0201] The present invention will be described in more detail with reference to the drawings. [Brief explanation of the drawing]

[0202] [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 graph shows a comparison between experimental data and literature. [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 graph shows a comparison between experimental data and literature. [Figure 10] This graph shows the relationship between time and mass flow rate. [Figure 11] The first initial oil droplet size distribution is shown. [Figure 12] The second initial oil droplet size distribution is shown. [Figure 13] The second initial oil droplet size distribution is shown. [Figure 14] Figure 13 is an explanatory diagram of the distribution of oil droplets that did not reach the cylinder wall. [Figure 15] This is a partial schematic diagram of a common rail system comprising a common rail and a high-pressure unit having a pump and valves. [Figure 16] This is a schematic diagram of a further embodiment of an injector used in the system according to the present invention, shown in the closed position. [Figure 17] Figure 13 is a schematic diagram of the injector, shown in the open position. [Modes for carrying out the invention]

[0203] 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.

[0204] Each injector 4 has a nozzle 5 with a nozzle opening 5', and a fine mist spray 8 of minute oil droplets 7 is released into the cylinder 1 under high pressure from the nozzle opening 5'.

[0205] 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.

[0206] However, in relation to improved lubrication systems, other principles have also been envisioned, such as injectors that direct a jet or spray onto the cylinder liner or piston ring pack.

[0207] 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.

[0208] In addition to the lubricating oil supply conduit 9 (which is a common supply conduit), 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.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] Figure 2 shows injector 4.

[0213] 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.

[0214] 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.

[0215] 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.

[0216] 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'.

[0217] 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.

[0218] 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.

[0219] 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".

[0220] 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.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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.

[0227] 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.

[0228] However, the actuator member 28 and the plunger member 29 can be held in an offset state from the rearmost position by adjusting the pressures in the pressure control port 4B and the pressure chamber 27 to an offset pressure level that creates a force acting on the actuator. Springs 28A and 29B are not fully extended during the rearward movement of the actuator member 28 and the plunger member 29, but are held in a slightly compressed state. This is possible because the forces of springs 28A and 29B change according to the compression length and generally follow a linear dependence with respect to the displacement from the rearmost position of the actuator member. The offset pressure level is smaller than the pressure level required to open and inject the check outlet valve 17.

[0229] In principle, the injector 4 can supply lubricating oil from one lubricating oil supply section at the inlet port 4A, and can further supply pressure oil or other pressurized liquid from a completely different supply section. However, generally, for simplicity and convenience, the pressure oil in the pressure control port 4B can be supplied from the same supply section as the lubricating oil at the inlet port 4A, but is supplied at a high pressure using, for example, a booster.

[0230] As is clear from the above embodiment, the lubricating oil supply conduit 9 communicates with the return line 13. This is also shown by a solid line 9” in FIG. 1, and the solid line 9” is connected to the lubricating oil supply conduit 9 on its extension line. When the control device 11 is an additional unit, the control device 11 will have at least four conduit connectors.

[0231] However, this is not essential. Optionally, the control device 11 includes a return outlet line 34 connected to the return conduit 13 as shown in FIG. 3b. In this case, the return conduit 13 communicates directly with the supply conduits 9’ and 9. This embodiment is shown by another dotted line 9’ in FIG. 1, and the dotted line 9’ is connected to the supply conduit 9 on its extension line. In this case, the return conduit 13 on the extension lines of the supply conduits 9 and 9’ directly supplies lubricating oil to the lubricating oil inlet port 4A of the injector 4 for injection into the cylinder, and the control device 11 is bypassed.

[0232] The following numerical values are non-limiting examples of possible operating pressures. The pressures in the return conduit 13 and the 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 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 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 high enough that, although well below the injection pressure of 37 bar, the actuator member 28 does not return fully to its rear position but maintains a predetermined distance from the rear position. By adjusting the pressure to a range of 10 - 30 bar to adjust this distance, the injection amount 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 position at the start of the injection phase.

[0233] Optionally, the injection amount is controlled by a flow meter inserted into the supply line 9 for a group of injectors or each single injector 4. The flow meter measures the flow (mass and / or volume) and is then used to manage that the injector(s) are operating properly.

[0234] 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 amount 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.

[0235] The above embodiment is known from International Publication No. 2019 / 114905; however, it differs in that the engine is equipped with a pressure gauge 35, which may also be called a pressure sensor. The pressure gauge 35 is to be used to measure the pressure in a lubricating oil supply conduit 9, which is a common rail for supplying lubricating oil to the injector 4.

[0236] Figure 2 shows pressure gauges 35 for each injector, but in some practical embodiments of the system, fewer pressure gauges may be provided. In some embodiments, only one pressure gauge is used for the lubricating oil supply conduit 9.

[0237] The signal from the pressure gauge regarding the actual pressure in the lubricating oil supply conduit 9 is then sent to the control unit and used to calculate the desired pressure obtained by controlling the high-pressure pump in the lubricating oil supply unit according to the engine load condition.

[0238] Alternatively, the high-pressure pump may not be adjustable, in which case the desired pressure in the lubricating oil supply conduit 9 is obtained by controlling a valve provided in relation to the high-pressure pump and used to connect the high-pressure pump to the lubricating oil supply conduit 9.

[0239] 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.

[0240] 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'.

[0241] 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.

[0242] However, in relation to improved lubrication systems, other principles have also been envisioned, such as injectors that direct a jet or spray onto the cylinder liner or piston ring pack.

[0243] 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.

[0244] The injector 4 receives lubricating oil from the lubricating oil supply unit 25, which includes a potential lubricating oil pump that raises the pressure of the lubricating oil to an appropriate level, via the lubricating oil supply conduit 9 (common supply conduit). For example, the pressure in the lubricating oil supply conduit 9 is in the range of 10-400 bar, preferably 25-100 bar, and optionally 30-80 bar, which is a typical pressure range for spray injectors, such as SIP injectors.

[0245] 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.

[0246] The above embodiment is known from International Publication No. 2019 / 114905; however, it differs in that the engine is equipped with a pressure gauge 35, which may also be called a pressure sensor. The pressure gauge 35 is to be used to measure the pressure in a lubricating oil supply conduit 9, which is a common rail for supplying lubricating oil to the injector 4.

[0247] Figure 5 shows pressure gauges 35 for each injector, but in some practical embodiments of the system, fewer pressure gauges may be provided. In some embodiments, only one pressure gauge is used for the lubricating oil supply conduit 9.

[0248] The signal from the pressure gauge regarding the actual pressure in the lubricating oil supply conduit 9 is then sent to the control unit and used to calculate the desired pressure obtained by controlling the high-pressure pump in the lubricating oil supply unit according to the engine load condition.

[0249] The electrical control signal from the control device 11 to the injector 4 is supplied in precisely timed pulses synchronized with the piston movement in the cylinder 1 of the engine. For example, for synchronization, the control device system 11 comprises a computer 11’ or is electronically connected, wired or wirelessly, to a computer 11’, which monitors parameters regarding the actual state and operation of the engine, such as the speed, load, and position of the crankshaft, and the position of the crankshaft reveals the position of the piston within the cylinder.

[0250] Figure 6 shows a main schematic view of the injector 4. Figure 6 is a schematic view including three different views of the exemplary injector, a top view, an end view, and a cross-sectional side view.

[0251] The injector 4 comprises a lubricating oil inlet port 112 for receiving lubricating oil from the lubricating oil supply conduit 9. The inlet port 112 is provided within an inlet valve housing 121, which comprises an inlet valve system 113 in communication with the inlet port 112 for regulating the amount of lubricating oil received from the lubricating oil supply conduit 9 during the lubrication phase. The injector 4 also comprises an outlet valve system 115 for regulating the lubricating oil distributed through the nozzle opening 5’. The rigid flow chamber 116 connects the inlet valve system 113 to the outlet valve system 115 for flowing lubricating oil 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 with bolts 124.

[0252] Figure 7 is an enlarged portion of the inlet valve system.

[0253] 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.

[0254] A push rod, exemplified as such, is provided in the flow path 129 to displace the inlet valve member 126 (ball). The push rod 131 is not fixed to the inlet valve member 126, but rather to a reciprocating solenoid plunger 133 driven by a solenoid coil 132. The solenoid plunger 133 is retracted by a plunger spring 134 when idle. When the solenoid coil 132 is energized by an electric current, the solenoid plunger 133 moves forward against the force of the plunger spring 134 until it stops relative to the plunger stop 135. The movement of the solenoid plunger 133 causes the push rod 131 to push the inlet valve member 26 away from the inlet valve seat 127, allowing the lubricating oil to flow through the inlet check valve 125 into the flow chamber 116.

[0255] In an advantageous embodiment, when idle, the push rod 131 is retracted by a predetermined distance from the inlet valve member (ball) 126, so that a free travel distance exists between the push rod 131 and the inlet valve member 126. When the solenoid coil 132 is energized, the push rod 131 is accelerated by the solenoid coil 132 over the free travel distance before colliding with the inlet valve member 126 after an initial acceleration. As a result, the inlet valve member 126 is displaced rapidly from the inlet valve seat 127 compared to a situation where the inlet valve member 126 moves with the push rod 131 in the initial part of the acceleration. The rapid displacement of the inlet valve member 126 is advantageous for precisely timing the start of lubrication oil injection into the cylinder 1. Optionally, the free travel distance can be adjusted by an adjustment screw 136 at the end of the solenoid plunger 133.

[0256] After the injection phase, the supply of lubricating oil from the inlet port 112 to the nozzle 5 is stopped by interrupting the current to the solenoid coil 132, which leads to the solenoid plunger 133 being pushed back by the plunger spring 134, and the inlet valve member 126 returns to the tight inlet valve seat 127 for the idle phase of the injection cycle.

[0257] 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.

[0258] 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.

[0259] 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.

[0260] 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.

[0261] The injector signal bus 212 connects the injector to the control device 11 in order to calibrate the injector by adjusting the amount of lubricating oil.

[0262] Figure 15 is a schematic diagram partially showing the common rail and the common rail system, including the pump and high-pressure unit.

[0263] If the pump is variable, the valve can be omitted.

[0264] The pump can be made variable in order to adjust the rotational speed of the pump and thereby adjust the output of the high-pressure pump in order to obtain the desired pressure in the lubricating oil supply conduit.

[0265] Alternatively, the pump may not be variable. Instead, a valve is used, located on the high-pressure pump and connecting it to the lubricating oil supply conduit. In this case, the valve is adjusted to regulate the pressure in the lubricating oil supply conduit to the desired pressure.

[0266] The valves are connected to the positive and negative pressure sides of the high-pressure pump.

[0267] Therefore, the valve can release pressure because it is connected to the negative pressure side of the high-pressure pump or to the return line to the lubricating oil supply.

[0268] The injector is generally of the type described in International Publication No. 2012 / 126473. This injector is also known as the Hans Jensen Lubricators E-sip injector. The injector can be operated electromechanically, for example, in the form of a solenoid valve or a piezoelectric element.

[0269] Figures 16 and 17 show further embodiments of an injector used in a system according to the present invention, shown in the closed and open positions, respectively.

[0270] The injectors shown in Figures 16 and 17 are electromechanically operated in the form of solenoid valves.

[0271] The injector is manufactured as a unit, and the open / close valve is an electromechanical valve integrated into the injector for injecting lubricating oil. The electromechanical open / close valve includes a spring-driven valve shaft.

[0272] Lubricant is injected by activating an open / close valve in the injector. This activation moves the valve stem of the open / close valve, injecting the lubricant. [Explanation of Symbols]

[0273] 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 in 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 36 Desired amount of lubricating oil 37. Calculated actual amount of lubricating oil 38. Signal from the flow meter 39 Control signals 40 Uncalibrated injector 41 Calibrated injectors 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 16 117 Outlet ball valve as an example of an outlet check valve 118 Outlet valve member 119 Outlet valve seat 120 Outlet valve spring 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 214 Pressurized oil supply line 215 Feedback control algorithm

Claims

1. A large, low-speed two-stroke engine comprising a cylinder (1) having a reciprocating piston inside and a lubrication oil system, wherein the lubrication oil system is A lubrication oil supply unit (25) including a lubrication oil pump that increases the lubrication hydraulic pressure to the lubrication oil pressure, which is the typical pressure range for a spray injector, 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 (9) connects the lubricating oil supply unit (25) and the lubricating oil injector (4), Equipped with, The aforementioned engine is The system further comprises a control device (11) for controlling the amount and timing of lubricant injection by at least one of the lubricant injectors (4). Each of the injectors (4) is A fluid connection is made to the lubricating oil supply conduit (9), and an inlet port is provided for receiving lubricating oil from the lubricating oil supply conduit (9), In the injection phase, a nozzle (5) is configured to inject lubricating oil into the cylinder (1) from the inlet port (4A) and has a nozzle opening (5') extending into the cylinder (1), Equipped with, The control device is configured to control and change the pressure in the lubricating oil supply conduit (9) within a range of 10 bar to 400 bar, preferably 25 bar to 100 bar, and optionally within a range of 30 bar to 80 bar, for a large, low-speed, two-stroke engine.

2. The large, low-speed two-stroke engine according to claim 1, wherein the desired pressure is based on one or more engine operating parameters.

3. The large, low-speed operating two-stroke engine according to claim 1 or 2, wherein the desired pressure is based on the engine load.

4. The large, low-speed, two-stroke engine according to any one of claims 1 to 3, wherein the desired pressure is also based on a measured value of the actual pressure in the lubricating oil supply conduit (9).

5. The aforementioned engine is The control device is connected to a computer (11'), or A mobile phone configured to communicate with the control device, A large, low-speed, two-stroke engine according to any one of claims 1 to 4, further comprising:

6. Each of the aforementioned injectors is In the nozzle, during the injection phase, an adjustable valve is opened and closed to allow lubricating oil to flow into the nozzle opening. A large, low-speed operating two-stroke engine according to any one of claims 1 to 5, further comprising the above.

7. Each of the injectors is a SIP injector, according to any one of claims 1 to 6, for a large, low-speed, two-stroke engine.

8. A method for lubricating a large, low-speed two-stroke engine comprising a cylinder (1) having a reciprocating piston inside, and a system, wherein the system is A lubrication oil supply unit (25) including a lubrication oil pump, 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 (9) 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) for controlling the amount and timing of lubricant injection by at least one of the lubricant injectors (4), Each of the injectors (4) is A fluid connection is made to the lubricating oil supply conduit (9), and an inlet port is provided for receiving lubricating oil from the lubricating oil supply conduit (9), In the injection phase, a nozzle (5) is configured to inject lubricating oil into the cylinder (1) from the inlet port (4A) and has a nozzle opening (5') extending into the cylinder (1), Equipped with, The aforementioned method, The steps include raising the pressure of the lubricating oil to the typical pressure range of the spray injector, and further performing a periodic operation. In the injection phase, pressurized liquid is supplied to the inlet port of the injector, force is applied to the valve, the valve body is moved inside the injector (4) by the force, and when the pressure rises above a predetermined limit, a predetermined volume of lubricating oil is pumped from the nozzle opening (5') into the cylinder (1). Includes, The aforementioned method, A method comprising the step of using the control device to change and control the pressure in the lubricating oil supply conduit (9) within a desired pressure range of 10 bar to 400 bar, preferably 25 bar to 100 bar, and optionally 30 bar to 80 bar.

9. A method for lubricating a large, low-speed two-stroke engine according to claim 8, wherein the desired pressure is based on the engine load and a measured value of the actual pressure in the lubricating oil supply conduit (9).

10. The computer (11') to which the control device is connected, or A mobile phone configured to communicate with the aforementioned control device, A method for lubricating a large, low-speed two-stroke engine according to claim 8 or 9, further comprising the step of providing the engine.

11. A method for lubricating a large, low-speed two-stroke engine according to any one of claims 8 to 10, comprising the step of providing the engine with an adjustable valve in the nozzle (5) that opens and closes to allow lubricating oil to flow from the pressure chamber in the injector to the nozzle opening (5') during an injection cycle.

12. A method for lubricating a large, low-speed two-stroke engine according to any one of claims 8 to 10, comprising the step of providing each of the injectors in the form of a SIP injector.

13. Use of the engine according to any one of claims 1 to 6 for spray injection into the cylinders of a large marine engine or a power plant combustion engine at a lubricating oil pressure in the range of 10 bar to 400 bar, preferably in the range of 25 bar to 100 bar.

14. Use of the engine according to claim 13 when using the engine according to claim 7, wherein the spray injection is SIP injection.

15. Use of the method according to any one of claims 8 to 11 for spray injection 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.

16. Use of the method of claim 15 when using the method of claim 12, wherein the spray injection is SIP injection.

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