Method for lubricating large two-stroke engine through controlled pressure change in common rail

Abstract

A large engine, in particular a marine engine or a power plant engine, and a method of lubricating the engine using spray injectors, in particular SIP injectors. According to the method, a controller is provided which is configured to vary and control the pressure in the lubricant supply conduit within a desired pressure range, and the desired pressure depends on a measurement of the engine load and the actual pressure in the lubricant supply conduit.

Description

[0001] Invention Field This invention relates to a large combustion engine, such as a large low-speed two-stroke engine, and a method for lubricating such an engine and its use.

[0002] More specifically, the present invention relates to a large, low-speed, two-stroke engine comprising a cylinder having reciprocating pistons and a lubrication system, the lubrication system comprising... - A lubricant supply source, including a lubricant pump, to increase the pressure of the lubricant to the typical pressure range of the spray nozzle. - Multiple lubricant injectors distributed along the cylinder periphery are used to inject lubricant into the cylinder at different locations on the periphery during the injection phase. - Lubricant supply conduit, connecting the lubricant supply source to the lubricant injector. The engine also includes a controller for controlling the amount and timing of lubricant injection from at least one lubricant injector. Each injector includes - An inlet port in fluid communication with the lubricant supply conduit for receiving lubricant. - A nozzle having a nozzle orifice extending into the cylinder, configured to inject lubricant from the inlet port into the cylinder during the injection phase.

[0003] Preferably, each injector includes an adjustable valve at the nozzle for opening and closing the flow of lubricant to the nozzle orifice during the injection phase.

[0004] This method relates to the lubrication of such large, low-speed two-stroke engines. More specifically, it relates to a method for lubricating a large, low-speed two-stroke engine comprising a cylinder with reciprocating pistons and a system including... - Lubricant supply sources, including lubricant pumps, - Multiple lubricant injectors distributed along the cylinder periphery are used to inject lubricant into the cylinder at different locations on the periphery during the injection phase. - Lubricant supply conduit, connecting the lubricant supply source to the lubricant injector. The engine also includes: - A controller for controlling the amount and timing of lubricant injection from at least one lubricant injector. Each injector includes: - An inlet port in fluid communication with the lubricant supply conduit for receiving lubricant from it. - A nozzle having a nozzle orifice extending into the cylinder, configured to inject lubricant from the inlet port into the cylinder during the injection phase. The method includes - Increase the lubricant pressure to the typical pressure range of the spray nozzle, and also include [this feature] in cyclic operation. - During the injection phase, pressurized liquid is supplied at the inlet port of the injector and a force is applied to the valve. This force drives the valve body to move inside the injector. When the pressure rises above a predetermined limit, a predetermined volume of lubricant is pumped into the cylinder through the nozzle orifice.

[0005] It should be noted that "adjustable" means that the degree to which the valve needle is pulled up and the duration for which it must remain open can be controlled to some extent. However, other types of valves can also be used.

[0006] In addition, the engine may also include - A computer (11') connected to the controller, or alternatively - A mobile phone that communicates with the controller.

[0007] Furthermore, the engine may further include - At least one flow meter used to measure the flow rate of lubricant.

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

[0009] Due to growing concerns about environmental protection, efforts are ongoing to reduce emissions from marine engines. This also involves the continuous optimization of lubrication systems for these engines, especially given increasing competition. One economic aspect receiving increasing attention is reducing fuel consumption, not only for environmental protection but also because it is a significant component of ship operating costs. Another concern is achieving adequate lubrication while reducing lubricant usage, as engine life should not be compromised by reduced fuel consumption. Therefore, continuous improvement in lubrication is necessary.

[0010] For the lubrication of large, low-speed, two-stroke marine diesel engines, there are several different systems, including spraying lubricating oil directly onto the cylinder liner or injecting the oil into the piston rings through an oil filler pipe.

[0011] Lubrication can be achieved via jet injection, which is a process of injecting a measured amount of lubricant in a compact jet into the cylinder liner or piston ring assembly. This is also known as pulse lubrication.

[0012] Alternatively, lubrication can be achieved as a spray injection, in which the lubricant is injected into the combustion chamber under high pressure. Thus, a fine mist of lubricant can be injected into the cylinder, preferably in the combustion chamber. The lubricant is provided in the form of atomized droplets. The injector used for spray injection is called a spray injector. A specific type of spray injection is SIP injection. The injector used for SIP injection is called a SIP injector. SIP injection will be described in further detail below.

[0013] EP1767751 discloses an example of a lubricant injector for a marine engine, in which a one-way valve is used to allow lubricant to enter a nozzle passage inside the cylinder liner. The one-way valve includes a reciprocating spring-loaded ball in a valve seat just upstream of the nozzle passage, the ball being displaced by pressurized lubricant. Ball valves are a conventional technical solution based on principles used since the early 20th century, such as the scheme disclosed in GB214922 of 1923.

[0014] Compared to traditional lubrication, a relatively new alternative lubrication method is commercially known as the Swirl Injection Principle (SIP). It is based on spraying atomized lubricant droplets into a scavenging vortex inside the cylinder. The spiraling upward vortex causes the lubricant to be drawn towards the top dead center (TDC) of the cylinder and pressed outward against the cylinder wall, forming a thin, uniform layer. This is detailed in international patent applications WO2010 / 149162 and WO2016 / 173601. The injector includes an injector housing containing a reciprocating valve member, typically a needle valve. This valve member (e.g., with a needle tip) closes and opens at precise timing to allow lubricant to enter the nozzle orifice. In current SIP systems, a spray of atomized droplets is typically formed at a pressure of 35-40 bar. In contrast, systems using denser oil jets to introduce oil into the cylinder use oil pressures below 30 bar, and often below 10 bar. In some types of SIP injectors, the high pressure of the lubricant is also used to move the spring-loaded valve member away from the nozzle orifice against the spring force, causing the high-pressure oil to be released as atomized droplets. The injection of oil causes a drop in oil pressure on the valve member, causing the valve member to return to its origin and remain there until the next lubricant cycle supplies high-pressure lubricant to the lubricant injector again.

[0015] In such large marine engines, multiple injectors are arranged around the circumference of the cylinder, each injector including one or more nozzle orifices for delivering a jet or spray of lubricant into the cylinder from each injector. Examples of SIP lubricant injector systems in marine engines are disclosed in international patent applications WO2002 / 35068, WO2004 / 038189, WO2005 / 124112, WO2010 / 149162, WO2012 / 126480, WO2012 / 126473, WO2014 / 048438, and WO2016 / 173601.

[0016] The optimization of spray in SIP lubrication is constantly evolving. Although lubricant injectors and fuel injectors share some similarities, they exhibit different performances and effects upon comparison. This is primarily attributed to the different operating conditions of the injectors, leading to varying effects such as viscosity, surface tension, and fluid pressure. Therefore, findings from fuel injection studies cannot be automatically transferred to lubricant injection, and the differences in performance can be surprising in some cases.

[0017] For SIP injection, in addition to minimizing fuel consumption, precise timing of control is crucial. Therefore, SIP systems are specifically designed for rapid responsiveness during the injection cycle.

[0018] Spray injection does not require the same level of precision control as SIP injection. Spray injection does not require the use of scavenging vortexes within the cylinder to distribute atomized lubricant droplets onto the cylinder liner.

[0019] With the introduction of the HJL Smartlube 4.0 system, the performance of lubrication systems has been improved. However, there is a need for a method that can automatically ensure the system delivers the required dosage of lubricant, unaffected by external disturbances such as variations in lubricant type, pressure, and temperature, as well as mechanical wear of components in the lubrication system, and ensure that most of the delivered lubricant is delivered in spray form.

[0020] The HJL Smartlube 4.0 system is a unique combination of compact design and advanced functionality. The system includes one or two high-pressure units for delivering lubricating oil to the injectors. The high-pressure units include a pump 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, control signals received from the controller independently control each injector.

[0021] One of the key factors in spray formation is cavitation in the nozzle, which results from the formation of vapor cavities within the liquid due to evaporation. Cavitation in the nozzle affects liquid atomization because it introduces significant disturbances into the liquid flow, thus destabilizing the jet. While cavitation in nozzles has been extensively studied in the field of fuel injection, research on cavitation in lubricant injectors is scarce.

[0022] WO2018 / 215645, with the same applicant as this application, discloses extensive explanations regarding the formation of steam bubbles. The contents of WO2018 / 215645 are incorporated herein by reference to avoid redundant explanations regarding cavitation.

[0023] The conclusions of these findings can be applied to lubricant injection, which, due to its varying viscosity, behaves differently from fuel injection, and cavitation at the nozzle exit is detrimental. In other words, parameters such as nozzle size, lubricant pressure, and viscosity should be selected to avoid cavitation, especially at the nozzle exit. This aligns with current commercial SiP (Ship Injection) systems used in marine engines, which operate with parameters that do not induce nozzle cavitation.

[0024] Due to the ongoing motivation to improve lubrication in large two-stroke natural gas and diesel engines (such as marine engines or power plant engines), cavitation design is advantageously part of the considerations for optimizing spray injection (especially SIP injection).

[0025] As stated above, existing technologies for lubricant injection conclude that cavitation, especially near the nozzle tip, is detrimental to spray stability, lubricant distribution, and results in poor spray controllability. Therefore, in lubricant injection practices for large marine engines, cavitation is not utilized in either jet or spray injection, such as SIP injection. The parameters for spray injection, particularly SIP injection, have consistently remained outside the range required to achieve cavitation.

[0026] However, contrary to the conclusions of existing technologies and against the trend in the field, further detailed research surprisingly revealed that lubricant cavitation in the nozzle can be used to provide stable, controllable spray jets and uniform lubricant distribution, which is a key factor in optimizing spray jets, such as SIP lubrication.

[0027] In the study leading to the invention disclosed in WO2018 / 215645, it was found that not only is cavitation itself beneficial to the spray formation of lubricants, but also the spray quality, controllability and stability are even improved when cavitation extends to the nozzle outlet.

[0028] In further research leading to this invention, it has been found beneficial to control the pressure of the lubricating oil delivered via the common rail. Studies have shown that controlling the pressure in the common rail affects how lubricating oil droplets move within the scavenging vortex of a marine two-stroke engine.

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

[0030] It has been confirmed that at low loads, smaller droplets cannot reach the cylinder wall surface. Furthermore, it has been confirmed that as the load increases, the size of the small droplets that fail to reach the cylinder wall also increases. This is attributed to the increased air vortex velocity and density. Therefore, more droplets are "captured," and more droplets break apart, which even traps more oil in the air.

[0031] It was also confirmed that common rail pressure affects the final position of the droplets on the cylinder wall.

[0032] It has been confirmed that controlling the pressure of the lubricating oil delivered via the common rail is important for influencing the size of the spray droplets injected into the cylinder, and thus also affects the distribution of the lubricating oil on the cylinder wall.

[0033] EP0049603A2 describes a system for supplying lubricant to a low-speed ignition engine. However, this document teaches timed lubrication to be applied between the piston rings. Furthermore, the document only addresses controlling the lubricant dosage based on the generated power. No mention is made of controlling and varying the pressure according to engine load. Additionally, the document does not specify the pressure used within the SIP injection range.

[0034] WO2023 / 088526 describes a large combustion engine and method in its introduction. It teaches that the system uses a lubricant with pressures within the SIP injection range. However, the document does not teach that a controller is set up to control and change the pressure in the lubricant supply conduit.

[0035] The prior art documents do not disclose a method or system for controlling the pressure in a common rail to affect the final position of droplets on the cylinder wall.

[0036] Summary of the Invention / Summary of the Invention The purpose of this invention is to provide an improvement to existing systems in order to ensure that most of the lubricating oil reaches the cylinder wall surface by adjusting the pressure in the lubricant supply conduit (preferably a common rail) to achieve the desired effect.

[0037] In particular, the aim is to improve the spray lubrication of spray injectors used in common rail systems of large combustion engines (such as large low-speed two-stroke engines). Furthermore, the aim is to improve SIP lubrication using spray injectors in the form of SIP injectors.

[0038] Another object of the present invention is to provide a system in which pressure variation is used to control the degree of atomization, thereby controlling the size of lubricant droplets in the spray.

[0039] However, the method according to the invention can also be used in large four-stroke combustion engines, such as marine engines or power plant combustion engines.

[0040] These objectives are achieved by a large combustion engine (e.g., a low-speed two-stroke engine), as described in the introduction and defined in the preamble of claim 1, characterized in that the controller is configured to control and change the pressure in the lubricant supply conduit within a desired pressure range, ranging from 10 bar to 400 bar, preferably from 25 bar to 100 bar, and optionally from 30 bar to 80 bar.

[0041] These objectives are also achieved by a lubrication method for a large combustion engine according to the invention, as described in the introduction and defined in the preamble of claim 7, characterized in that the method comprises the following steps: The pressure in the lubricant supply conduit is controlled and varied by a controller within the desired pressure range, ranging from 10 bar to 400 bar, preferably from 25 bar to 100 bar, and optionally from 30 bar to 80 bar.

[0042] The lubricant supply conduit is preferably a common rail.

[0043] The lubricant supply source is preferably a high-pressure device. The high-pressure device preferably includes a pump.

[0044] The preferred lubrication supply system is the HJL Smartlube 4.0 system.

[0045] This invention can also be used in the lubrication principle of a modified engine, wherein multiple lubricant supply conduits are replaced by a single common lubricant supply conduit. A high-pressure unit then delivers lubricant to the injectors via a "common rail" system, in which all injectors of an engine cylinder, or a subgroup of injectors for a single engine cylinder, receive lubricant jointly and simultaneously through a single common lubricant supply conduit.

[0046] Optionally, a return line is provided for returning lubricant from the injector.

[0047] A large two-stroke engine includes a cylinder with reciprocating pistons and multiple lubricant injectors distributed along the cylinder periphery to inject lubricant into the cylinder at different locations on the cylinder periphery during the injection phase. Examples of such engines include marine engines or large power plant engines. Typically, this engine burns fuel oil.

[0048] The term "injection phase" refers to the time it takes for lubricant to be injected into the cylinder by the injector. The term "injection cycle" refers to the time required for the injector to inject lubricant into the cylinder until the next injection. This terminology is consistent with the aforementioned prior art.

[0049] The term "injector" is used herein to refer to a lubricant injection valve system comprising a housing having a lubricant inlet and a single injection nozzle having a nozzle outlet from which lubricant exits the nozzle in the form of a spray and enters the cylinder. The nozzle outlet has an outlet orifice with an outlet size S. For example, the outlet orifice may be a circle with a diameter D, in which case the diameter D is a measure of the size S. If the outlet orifice deviates from a circle, a possible measure of the size S is the orifice area or the average diameter; the latter is useful in cases of slightly oval or elliptical shapes that deviate from a circle. For example, for a non-circular outlet orifice, the cross-sectional size is the equivalent diameter calculated as twice the square root of the ratio of the cross-sectional area to pi ≈ 3.14. The nozzle has one or more nozzle outlets, typically no more than two.

[0050] In spray injectors, such as SIP injectors, the nozzle includes a spray orifice shaped as a channel of length L (e.g., between 0.5 and 1 mm), one end of which forms the nozzle outlet. In typical injectors, the nozzle includes a capsule-like orifice for directing lubricant flow to the spray orifice, which extends from the capsule-like orifice to the nozzle outlet. Typically, the central longitudinal axis of the spray orifice forms an angle with the central longitudinal axis of the capsule-like orifice, for example, in the range of 30 to 90 degrees. The cross-sectional area of ​​the capsule-like orifice perpendicular to its central longitudinal axis is typically larger than the cross-sectional area of ​​the spray orifice perpendicular to its central longitudinal axis.

[0051] Changing the pressure allows control over the degree of atomization, thereby controlling the size of the lubricant droplets in the spray. This is crucial for controlling the location of the lubricant mist and droplets reaching the cylinder liner under different engine operating conditions.

[0052] Optionally, a controller is provided. The controller includes a computer or is connected to a computer electronically or via a wired connection. Advantageously, the computer is configured to monitor parameters of the engine's actual load and motion. With the cooperation of the computer, based on these parameters, the controller controls the amount and timing of lubricant injection via the injectors during the injection phase. In an advantageous embodiment, the controller is configured to control the lubricant pressure and optionally also control the temperature of the lubricant in the common rail.

[0053] Preferably, cavitation is formed in the lubricating oil within the injector. In the research leading to this invention, it has been found that cavitation is beneficial to the formation of the lubricant spray. Surprisingly, it has been found that the distribution of droplets in the spray can be improved to lubricate the cylinder walls.

[0054] In order to form a spray, the main pressure drop must occur at the last orifice of the nozzle. This can be explained by the orifice equation [1] shown below (1):

[0055] In (1), Q is the volumetric flow rate. It is the flow coefficient. It is the area of ​​the throttling orifice. It is the coefficient of thermal expansion (for incompressible fluids, =1, which is a reasonable assumption for cylinder lubricating oils) [Ravendran R, Jensen P, De ClavilleChristiansen J et al. Rheological behavior of lu-brication oils used in two-stroke marine engines. Industrial Lubrication and Tribology 2017; 69(5): 750–753. DOI:10.1108 / ILT-03-2016-0075], It is the pressure difference across the throttling orifice. It is fluid density. It is the area ratio, that is, the ratio of the diameter of the throttling orifice to the diameter of the pipe. = D2 / D1.

[0056] In order for oil to cavitation to occur, the cavitation number must be close to or less than 1. The cavitation number is shown in (2).

[0057]

[0058] In (2), It is ambient pressure (the pressure in the cylinder when injection occurs). It is the vapor pressure of the fluid. It is fluid density. It is the fluid velocity. Most of the variables in (2) are constants. It varies slightly with engine load. The cavitation number varies slightly with temperature, so because these effects are quite small, the oil velocity has the greatest impact on it. Remember this. As can be seen from (1), the cavitation number necessarily increases with... It decreases as it increases.

[0059] The following explains the numerical simulations performed to record the effects obtained according to the present invention.

[0060] When lubricating oil is injected into the scavenging air of a two-stroke marine engine, the droplets are affected by the scavenging air. The motion of these droplets is determined by the Stokes number (3).

[0061]

[0062] In (3), t is the time constant due to the exponential decay of particle velocity caused by drag. It is the velocity of the particle. The Stokes number is the characteristic length of the particle shape; for a sphere, it is the diameter. From the Stokes number, we can deduce that particles with low Stokes numbers follow the fluid's motion very well. In the case of an oil droplet in scavenging gas, this means the droplet follows the scavenging gas's motion very well. Particles with high Stokes numbers are governed by their own inertia and move along their initial trajectory, almost unaffected by the scavenging gas flow.

[0063] The degree to which oil droplets are affected by the scavenging airflow will affect their trajectory and ultimately their final position in the cylinder.

[0064] Since the time constant of the Stokes number is not easy to analyze and determine, droplets in the scavenging gas are simulated to determine the extent to which they are affected by the scavenging gas flow.

[0065] This invention is based on a simulation study of how to reduce cylinder oil supply rate. The model was developed based on the only common rail cylinder lubrication system for large two-stroke marine diesel engines, as explained in “N. Kristensen, 2019, “HJ Common Rail Lubrication System”, CIMAC Congress”.

[0066] It uses a solenoid-driven valve to atomize the lubricating oil. The injector operates based on the principle of swirl injection, as explained in, for example, 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 oil is injected upwards along the cylinder liner before the piston passes during the compression stroke. Therefore, the goal of this current research is to develop and validate a model for studying the principle of swirl injection.

[0067] To demonstrate simulation-based research, a numerical framework is needed, as described below.

[0068] The simulation performed was a computational fluid dynamics model. The governing equations for this problem are the continuity equation (4), momentum equation (5), energy equation (6), and composition equation (7):

[0069] in,

[0070] In equation 3-7, It's density. It is a velocity vector. It's pressure. It is gravitational acceleration. It is enthalpy. It is heat flux. It is the component mass fraction. It is the effective dynamic viscosity. It is kinematic viscosity. It is the identity matrix. It is the shear stress tensor. The turbulence model used is... The model, as 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”, is dominated by the following equations:

[0071]

[0072] in It is turbulent kinetic energy. It is the turbulent kinetic energy dissipation rate. It is the turbulent kinetic energy generation rate. It is the effective diffusion coefficient. C These are different model constants. Simulations using Unsteady Reynolds Averaged Navier-Stokes (URANS) show that the maximum Courant-Friedrichs-Lewy (CFL) number is less than 1.

[0073] The equations were solved to obtain the scavenging gas flow rate, and then compared with literature results to demonstrate accuracy. This is in Figure 3 and Figure 9The explanation is as follows.

[0074] The experimental data in the two figures above, as well as the comparisons with the literature, are from a study: "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". Figure 3 and Figure 9 It can be seen that the accuracy of the scavenging airflow should be sufficient to determine the effect of scavenging on particle trajectories.

[0075] In the simulation, particles are injected into a sweeping airflow, and their motion is determined by Newton's second law.

[0076]

[0077] Where F is the net force acting on the particle, m is the mass of the particle, and a is the acceleration. (11) can be described in more detail as follows:

[0078] The subscript p refers to a particle. t is velocity, m is time, m is mass, and F is force.

[0079] The calculation of buoyancy is shown in (13).

[0080] in It is the density of particles. It is the density of the scavenging air. It is gravitational acceleration. It is the volume of the particle. The drag can be calculated as shown in (14).

[0081]

[0082] here It is the drag coefficient. It is the velocity of the fluid. It is the velocity of the particle. It is the cross-sectional area of ​​the particle in the flow direction. In the simulation, equation (12) is solved for each time step and for each particle, so having a small CFL number will well approximate the exponential decay of the particle velocity due to drag.

[0083] The initial velocity of the particles entering the cylinder was determined experimentally using the Bosch 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". These measurements are as follows: Figure 10 As shown.

[0084] from Figure 10 As can be seen, the mass flow rate does not increase instantaneously when the valve opens. This is mainly due to the speed of the valve needle movement. Because the mass flow rate does not increase instantaneously, the initially injected oil is not sprayed in a mist form.

[0085] By using The particle velocity is calculated based on the mass flow rate. Simulations are performed using two different initial droplet size distributions, such as... Figure 11 and Figure 12 As shown.

[0086] These two distributions have completely different shapes, but the key difference lies in the number of droplets they each contain.

[0087] Figure 12 The distribution within contains many very small droplets, and Figure 11 The distribution in [the sample size] is normally distributed, but the median is approximately 150 μm, which is significantly higher than [the median value]. Figure 12 Distribution within.

[0088] These two droplet size distributions were used as inputs to a scavenging simulation model in the cylinder. This simulation model can predict the proportion of droplets that reach the cylinder wall.

[0089] If using Figure 12 The distribution of the injected mass is such that approximately 42% of the injected mass reaches the cylinder wall, while for... Figure 11 Approximately 99.5% of the injected mass reaches the cylinder wall. Therefore, droplet size distribution has a significant impact on the amount of oil reaching the wall.

[0090] The mathematical model for oil spray during scavenging revealed that in simulated engines, under low loads, the smallest droplets in the spray do not reach the cylinder walls at all. This also applies under high loads, but the limit for droplets reaching the cylinder walls varies with the load. Figure 13 and 14 As shown in the figure, Figure 13 For distribution, Figure 14 The results are used in connection with this distribution.

[0091] It has been observed that the size of the droplets required to avoid reaching the cylinder walls varies with load. The actual distribution of oil droplets formed in the engine depends on scavenging air, but also to a large extent on the pressure in the nozzles. An example of droplet distribution is shown below. Figure 13 As shown. Figure 13 The distribution of the droplets is shown. Figure 14 The image shows droplets that did not reach the cylinder wall. Blue particles represent droplets in the scavenging air that did not reach the cylinder wall.

[0092] It is generally believed that droplet size is inversely proportional to the pressure behind the injector valve needle. Therefore, when engine load changes, it is advantageous to alter the pressure in the common rail, thereby achieving greater droplet adhesion to the cylinder wall.

[0093] Figure 11 and Figure 12 The distribution differences between the droplets are illustrated through simulations to show how small droplets closely follow the streamlines and therefore do not ultimately reach the cylinder wall. Larger droplets that initially have a trajectory toward the cylinder wall are affected, but not to the point of not reaching the wall at all.

[0094] This indicates that, in order for spray technology, especially SIP technology, to operate effectively, the Stokes number of droplets should not be too low.

[0095] To influence the initial Stokes number of a droplet, the droplet's inertia must be affected or the fluid in the cylinder must be altered. The fluid in the cylinder varies in both velocity and density with engine load, as shown in (14).

[0096] As one study shows: "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 the same applies to the overall fluid velocity.

[0097] The jet pressure can be used to influence the initial Stokes number of the droplet, as shown in the simulation.

[0098] Therefore, experiments and studies have shown that controlling injection pressure can help optimize system efficiency when engine load changes.

[0099] In practice, the method according to the invention is used to control common rail pressure for a given parameter.

[0100]

[0101] In order for the injector to operate quickly to achieve its intended function, it is important that the injector can be operated within a given range of parameters.

[0102] The method according to the invention relates to lubricating a large, low-speed, two-stroke engine, the engine including a cylinder with reciprocating pistons and a system comprising: - Lubricant supply sources, including high-pressure pumps, - Multiple lubricant injectors distributed along the cylinder periphery are used to inject lubricant into the cylinder at different locations on the periphery during the injection phase. - Lubricant supply conduit, connecting the lubricant supply source to the lubricant injector. The engine also includes - A controller for controlling the amount and timing of lubricant injection from at least one lubricant injector. - A computer or mobile phone connected to the controller. Each injector includes: - An inlet port in fluid communication with the lubricant supply conduit for receiving lubricant. - A nozzle having a nozzle orifice extending into the cylinder, configured to inject lubricant from the inlet port into the cylinder during the injection phase. - An adjustable valve at the nozzle is used to open and close during the injection cycle to allow lubricant to flow into the nozzle orifice. This method includes loop operations: - During the injection phase, pressurized fluid is supplied to the inlet port of the injector and a force is applied to the valve. This force drives the valve body to move inside the injector, and when the pressure rises above a predetermined limit, a predetermined volume of lubricant is pumped into the cylinder through the nozzle orifice. - Install at least one pressure gauge to measure the pressure in the lubricant supply conduit. - Measure the pressure in the lubricant supply conduit using at least one pressure gauge. - The measured pressure is converted into a control signal in the controller and sent to the lubricant supply source to obtain the desired pressure in the lubricant supply conduit, taking into account the actual engine load.

[0103] Alternatively, in a loop operation, the method may include: - During the injection phase, pressurized fluid is supplied to the inlet port of the injector and a force is applied to the valve. This force drives the valve body to move inside the injector, and when the pressure rises above a predetermined limit, a predetermined volume of lubricant is pumped into the cylinder through the nozzle orifice. - After the injection phase, the valve body retracts by discharging pressurized fluid from the injector. - During retraction, the pressure chamber in the injector is refilled with lubricant for subsequent injection phases.

[0104] The control signals transmitted to the lubricant supply source can be used for: - The output of the high-pressure pump is regulated to achieve the desired pressure in the lubricant supply conduit. In this case, the pump speed is regulated.

[0105] or - A valve is regulated, which is located at the high-pressure pump and connects the high-pressure pump to the lubricant supply conduit. In this configuration, the output of the high-pressure pump remains constant, and the valve regulation is used to adjust the pressure in the lubricant supply conduit to the desired pressure. Preferably, the valve is connected to both the pressure side and the suction side of the high-pressure pump. Thus, the valve can release pressure because it is connected to either the suction side of the high-pressure pump or the return line to the lubricant supply source.

[0106] By controlling the pressure in the lubricant supply conduit, the droplet size can be affected by adjusting the pressure in the common rail, ensuring that most of the lubricating oil reaches the cylinder wall surface and achieving the desired effect.

[0107] The controller controls and regulates the pressure in the lubricant supply conduit based on measured engine load and actual pressure in the lubricant supply conduit.

[0108] Furthermore, the controller can control the adjustable valve and adjust the stroke length of the plunger-type valve component, thereby allowing for variable adjustment of the lubrication dosage between injection phases via a stroke length adjustment mechanism. Adjustment is achieved when the plunger has not fully retracted to its maximum feasible retraction position. Since the plunger's stroke always reaches the same position, such as the same forward position, the stroke length is adjusted by changing the plunger's retraction position after retraction.

[0109] The controller can be built into the injector, or it can be connected to the injector and flow meter via wired or wireless means.

[0110] The controller can also be set to control the type of lubricant used.

[0111] In some embodiments, the maximum feasible retraction position of the plunger is the furthest rearward feasible position from the nozzle orifice, but the plunger may remain at a certain distance from the furthest feasible position.

[0112] The amount of ink injected in the next stroke can be adjusted by changing this distance, as the stroke length is reduced relative to the maximum feasible retraction position. The effect is similar to the end stop of the adjustable screw in WO02 / 35068; however, the stroke length adjustment mechanism can be centrally located and positioned away from the injector, in contrast to the injector in WO02 / 35068.

[0113] The engine according to the invention may include a hydraulically driven inlet valve system, wherein each injector includes: - A lubricant inlet port in fluid communication with the lubricant supply conduit for receiving lubricant; - A nozzle having a nozzle orifice extending into the cylinder, configured to inject lubricant from the inlet port into the cylinder during the injection phase. - An outlet valve system located at the nozzle is used to open and close during the injection cycle to allow lubricant to flow into the nozzle orifice; - The pre-chamber inside the injector, located between the lubricant inlet port and the outlet valve system, is used to receive and accumulate a predetermined volume of lubricant from the inlet port before the injection stage; - The outlet valve system is configured to open during the injection phase once the pressure at the pre-chamber and outlet valve system rises above a predetermined pressure limit, so that lubricant flows from the pre-chamber through the outlet valve system to the nozzle orifice, and is configured to close the outlet valve system after the injection phase.

[0114] - A pressure control port in fluid communication with the pressure control conduit for receiving pressurized liquid during the injection phase; - Pressure chamber, connected to the pressure control port, for periodically receiving pressurized liquid from the pressure control port during the injection phase and discharging it after the injection phase; - A reciprocating hydraulically driven actuator plunger, in contact with a pressure chamber and pre-compressed by the spring load of an actuator plunger spring, is configured to move by pressurized fluid in the pressure chamber during the injection phase, and is configured to cause the lubricant pressure in the pre-chamber to rise above a predetermined pressure limit by its movement during the injection phase.

[0115] The engine also includes a stroke length adjustment mechanism for variably adjusting the stroke length of the reciprocating hydraulically driven actuator plunger. In this embodiment, the stroke length adjustment mechanism is configured to variably adjust the amount of pressurized fluid discharged from the pressure chamber between injection phases.

[0116] The effect of variable adjustment is similar to the end stop of the adjustable screw in WO02 / 35068; however, the stroke length adjustment mechanism can be centralized and located away from the injector, which is the opposite of the injector in WO02 / 35068.

[0117] In some practical embodiments, the stroke length adjustment mechanism includes a pressure regulator for variably adjusting the no-load pressure in the pressure chamber between injection phases, wherein the no-load pressure is below a predetermined limit so as to only partially offset the spring load of the actuator plunger spring acting on the actuator plunger, thereby variably adjusting the retraction position of the actuator plunger.

[0118] Due to the back pressure in the cylinder, the outlet valve system is closed, which also prevents lubricant from entering the cylinder unless the outlet valve opens. Furthermore, the outlet valve system helps to shorten the closing time after injection, increasing the accuracy of the timing and volume of lubricant injection.

[0119] An engine including a hydraulically driven inlet valve system can be operated according to a method comprising a stroke length adjustment mechanism configured to variably adjust the amount of pressurized liquid discharged from the pressure chamber between injection phases, the method comprising adjusting the stroke length between injection cycles by adjusting the amount of pressurized liquid discharged from the pressure chamber after the injection phase.

[0120] Engines and methods including a hydraulically driven inlet valve system are known from WO 2019 / 114905. However, this engine differs in that it includes a pressure gauge. This pressure gauge will be used to measure the pressure in the lubricant supply conduit.

[0121] The engine according to the invention may further include an electrically driven inlet valve system, wherein each injector includes: - Lubricant inlet port for receiving lubricant from the lubricant supply conduit; - A nozzle with a nozzle orifice extending into the cylinder for injecting lubricant from the inlet port into the cylinder. - An outlet valve system located at the nozzle is used to open and close during the injection cycle to allow lubricant to flow to the nozzle orifice; the outlet valve system is configured to open during the injection phase once the pressure at the outlet valve system rises above a predetermined limit to allow lubricant to flow to the nozzle orifice, and to close the outlet valve system after the injection phase. In this embodiment, each injector may include an electrically driven inlet valve system electrically connected to a controller and disposed between the lubricant inlet port and the nozzle, for opening or closing the lubricant flow from the lubricant inlet port to the nozzle according to an electrical control signal received from the controller, thereby regulating the lubricant distributed through the nozzle orifice; wherein the inlet valve system is located upstream of and away from the nozzle, and upstream of and away from the outlet valve system.

[0122] According to a specific embodiment of this type, the inlet valve system may include an inlet check valve having an inlet valve member pre-pressed onto an inlet valve seat by an inlet valve spring, and configured to allow lubricant to flow from a lubricant inlet port to an outlet valve system when the inlet valve member is displaced from the inlet valve seat against the force of the inlet valve spring; wherein the inlet valve system further includes an electrically driven rigid displacement member for displacing the inlet valve member from the inlet valve seat during lubricant injection.

[0123] To provide better control over the speed and volume of lubricant sprayed by the injectors, each injector includes an electrically driven inlet valve system electrically connected to the controller and positioned between the lubricant inlet port and the nozzle. This system opens or closes the flow of lubricant from the lubricant inlet port to the nozzle based on electrical signals received from the controller, thereby regulating the lubricant distribution through the nozzle orifice. The inlet valve system is positioned upstream of and away from the nozzle, and it is also positioned upstream of and away from the outlet valve system.

[0124] The injector's inlet valve system measures the amount of lubricant injected during the time the inlet valve system remains open during the injection phase. This time is determined by the controller.

[0125] An engine including an electrically driven inlet valve system can be operated according to a method comprising sending an electronically controlled signal from a controller to the electrically driven inlet valve system to initiate an injection phase, thereby causing lubricant to flow from a lubricant supply conduit through a lubricant inlet port, through the inlet valve system, into a conduit that fluidly connects the inlet valve system and the outlet valve system, increasing the pressure in the conduit and at the outlet valve system by the lubricant inflow, causing the outlet valve system to open by the pressure rise so that lubricant flows from the conduit to the nozzle orifice, and is injected into the cylinder through the nozzle orifice; at the end of the injection phase, changing the electronically controlled signal sent from the controller to the inlet valve system and causing the inlet valve system to close the lubricant supply from the lubricant inlet port to the conduit.

[0126] Engines and methods commonly known to include electrically driven inlet valve systems are derived from WO2019 / 114903.

[0127] According to a further embodiment, the engine is unique in that its lubrication system is selected from mechanical drive systems, hydraulic drive systems, and common rail systems.

[0128] The principle of this invention is flexible and can be used in different lubrication systems.

[0129] According to a further embodiment, the engine is unique in that the pressure gauge is located in the lubricant supply conduit connected to the injector.

[0130] This allows for the measurement of the actual pressure of the fluid entering the injector. The pressure gauge can be positioned directly in front of the inlet port of a single injector, or alternatively, it can be positioned in a common supply conduit for multiple injectors (e.g., multiple injectors in a single cylinder).

[0131] In some embodiments, the method includes controlling the amount of conditioning lubricant via feedback control / regulation, such as PID regulation or more complex model-based regulation.

[0132] In some embodiments, the method includes storing the adjustment value in the controller's database.

[0133] The method and engine according to the invention are particularly suitable for spraying, such as SiP (Self-Injection) injection, into the cylinders of large marine engines or power plant combustion engines at lubricant pressures ranging from 10 bar to 400 bar, preferably from 25 bar to 100 bar. The method is also suitable for lubrication combining spraying (e.g., SiP injection) and ring assembly injection. The injection into the ring assembly can be a lubricant spray or a compact lubricant jet.

[0134] In particular, the method and engine according to the invention are especially suitable for SIP injection using the type of injector generally described in WO 2012 / 126473, also known as the Hans Jensen Lubricant E-sip injector.

[0135] definition The term "adjustment" refers to the process of adjusting the amount of lubricant to meet the required level when the engine is in use.

[0136] The term "adjustment" refers to the process of correcting the amount of lubricant when calibrating an injector.

[0137] The term "injector" is used to refer to an injection valve system, including a housing having a lubricant inlet and one or more injection nozzles, the injection nozzles having nozzle orifices as lubricant outlets, and a movable valve member within the housing that opens and closes the passage for lubricant to enter the nozzle orifice. Although the injector has a single nozzle extending through the cylinder wall into the cylinder, the nozzle itself may optionally have more than one orifice when the injector is properly installed. For example, a nozzle with multiple orifices is disclosed in WO2012 / 126480.

[0138] The term "injection phase" refers to the time during which lubricant is injected into the cylinder through the injector.

[0139] The term "no-load phase" is used to refer to the time between injection phases.

[0140] The term "no-load condition" refers to the state in which a component is in a no-load phase.

[0141] The term "no-load phase position or orientation" refers to the position or orientation of a movable part when it is in an unloaded state during the no-load phase, in contrast to the position during the injection phase.

[0142] The term "injection cycle" is used to refer to the time required from the start of an injection sequence until the start of the next injection sequence. For example, an injection sequence may involve a single injection, in which case the injection cycle is measured from the start of one injection phase to the start of the next. Alternatively, an injection sequence may involve multiple injections, such as multiple injections above the piston before it reaches top dead center, for example, the first injection of one lubricant, followed by another injection of a different lubricant, and possibly additional lubricants and / or additives. Such secondary or multiple injections result in the oil mixing within the cylinder before the piston reaches top dead center. For example, there may be one injection cycle per engine revolution. However, it is also possible for there to be one injection cycle after several engine revolutions.

[0143] The term "timing" in injection refers to the start time of the injection phase of the injector, which is adjusted relative to the specific position of the piston within the cylinder.

[0144] The term "frequency" in injection refers to the number of times the injector repeats an injection per engine revolution. If the frequency is 1, there is one injection per revolution. If the frequency is 1 / 2, there is one injection every two revolutions. This terminology is consistent with the prior art described above.

[0145] The term "pressurized lubricant" refers to a lubricant supplied at sufficiently high pressure so that it can be injected into the cylinder as a jet or spray. This contrasts with oil injection between piston rings via a filler line. The pressure depends on the purpose and form of the injection and is typically above 10 bar. For spray injection, especially SIP injection, the pressure is often even higher, such as above 25 bar.

[0146] The term "flow meter" is used to refer to a component that can measure flow rate, such as pressure difference, viscosity, temperature, or quantity, regardless of the method used.

[0147] Actual Implementation Large engines, such as low-speed two-stroke engines, optionally marine engines or power plant engines, include cylinders with reciprocating pistons inside, and multiple lubricant injectors fixed to and extending through the cylinder walls. The injectors are distributed along the cylinder periphery and configured to inject lubricant into the cylinder at different locations on the cylinder periphery during the injection phase. For example, large engines, such as low-speed two-stroke engines, are large engines in marine engines or power plants. Typically, these engines burn diesel or gaseous fuels, such as natural gas.

[0148] The engine also includes a lubricant supply source for supplying pressurized lubricant, typically pressurized by a lubricant supply pump. Optionally, the engine includes more than one lubricant supply source, correspondingly more than one type of lubricant, and correspondingly more than one lubricant supply pump.

[0149] Each of the multiple injectors connects its respective lubricant inlet to a lubricant supply source via a corresponding lubricant supply conduit. Each lubricant supply source includes, but is typically, a pressure source, a lubricant pump, which increases the pressure of the corresponding lubricant to a sufficient level. For the system described, it is sufficient to provide a constant lubricant pressure at the corresponding lubricant inlet of the injector.

[0150] The injector is configured according to the type of lubricant to be injected. The inlet can be used not only to provide and add lubricant, but also to provide and add any possible additives. For example, the injector may optionally have multiple inlets, one for the lubricant (such as lubricating oil) and one for additives.

[0151] The engine also includes a controller. The controller is configured to control the amount and timing of lubricant injected from multiple injectors. Optionally, the injection frequency is also controlled by the controller. For precise injection, it is advantageous if the controller is electronically connected to or includes a computer that monitors parameters of the engine's actual load and motion. These parameters can be used to optimize injection control.

[0152] Optionally, the controller is provided as an add-on system for upgrading existing engines. Another advantageous option is to connect the controller to a human-machine interface (HMI), which includes a display for monitoring and an input panel for adjusting and / or programming parameters of injection profiles and optional engine states. Electronic data connectivity may be wired, wireless, or a combination thereof.

[0153] In a specific embodiment, the injector includes a lubricant inlet for receiving lubricant from a lubricant supply conduit for injecting the lubricant into the cylinder. The lubricant inlet of the injector is connected to a lubricant supply source via the lubricant supply conduit.

[0154] The injector has a lubricant flow path from the lubricant inlet to at least one nozzle for lubricant to flow from the lubricant inlet into the cylinder through at least one nozzle.

[0155] The injector includes one or more nozzles, such as two nozzles. Each nozzle has a nozzle orifice extending into the cylinder for injecting lubricant during the injection phase. Optionally, the nozzle has more than one orifice. For example, a nozzle with multiple orifices is disclosed in WO2012 / 126480. In some embodiments, the injector includes a single nozzle with a single nozzle orifice.

[0156] Specifically, each injector includes an internal actuator-driven valve system in the lubricant flow path, wherein the valve system is configured to selectively switch from an unloaded state without injection to an injection state, and to inject lubricant into the cylinder through at least one nozzle during the injection phase according to a received injection phase signal.

[0157] Each injector includes an actuator for driving the valve system. The actuator is functionally connected to and configured to be activated by the controller to selectively drive the valve system and, under the controller's control, induce lubricant injection as a result of the controller activating the actuator. The valve system, under the controller's control, is used to select the amount, timing, and sequence of injection.

[0158] During operation, the actuator is activated by the controller to initiate the lubricant injection phase. This opens the valve system, allowing lubricant to flow through the flow path and be injected into the cylinder. At the end of the injection phase, the actuator closes the valve system and stops the lubricant supply.

[0159] Example of pressure control In a specific embodiment, the engine includes a lubricant supply conduit containing lubricant at a desired pressure and connected to the aforementioned Esip injector.

[0160] The injector features an integrated on / off valve, preferably a solenoid valve, which significantly simplifies cable laying and installation by having only one pressurized lubricating oil common supply line (eliminating the need for a return line), making metering proportional to the opening time of the solenoid valve. Preferably, a separate local control box is provided for opening / closing the injector based on signals from the ship's engine / control unit.

[0161] Electromechanically adjustable injectors designed for cylinder lubrication of large diesel engines offer advantages over existing lubrication systems. System-wise, they allow for independent adjustment of lubricant quantity and timing.

[0162] This function relies solely on a control box, which can individually or collectively control the timing and opening duration of each injector. This can occur independently of other on / off valves and is limited only by the speed at which the on / off valves in the injector execute on / off cycles.

[0163] The measured flow rate is used to control the delivery volume relative to the planned volume. For a given deviation within a given time period, the relevant local control box can correct the opening time of the solenoid valves of the relevant injector or multiple relevant injectors.

[0164] In another embodiment, the engine includes a lubricant supply conduit and a pressure control conduit. The lubricant supply conduit contains lubricant at a first pressure, and the pressure control conduit contains pressurized fluid at a pressure higher than the first pressure. In this case, the injector includes an internal hydraulically driven pumping system, wherein the pressurized fluid drives the pumping system within the injector housing, thereby pressurizing and ejecting the lubricant within and from the injector. The injector includes a lubricant inlet port in fluid communication with the lubricant supply conduit for receiving lubricant therefrom for injection into the cylinder. The injector also includes a pressure control port in fluid communication with the pressure control conduit for receiving pressurized fluid therefrom during the injection phase.

[0165] The injector includes a front chamber inside the injector, located between the lubricant inlet port and the outlet valve system, for receiving and accumulating a predetermined volume of lubricant from the inlet port before the injection phase.

[0166] The pressure chamber in the injector is connected to a pressure control port for receiving pressurized fluid from the pressure control port during the injection phase. The pressurized fluid in the pressure chamber drives a pumping system in the injector. The pumping system includes a reciprocating hydraulically driven actuator plunger that contacts the pressure chamber and is preloaded by the spring load of an actuator plunger spring. It is configured to be driven during the injection phase by the pressurized fluid in the pressure chamber, for example, in a direction toward the nozzle. This causes the lubricant pressure in the pre-chamber to rise above a predetermined limit, and pumps a predetermined volume of lubricant through a check valve and a nozzle orifice into the cylinder.

[0167] injection Optionally, the injection phase includes multiple injections, such as multiple injections above the piston before it passes the injector on its way to top dead center, for example, a first injection of lubricant, followed by another injection of lubricant, and possibly additional lubricant and / or additives. Such secondary or multiple injections, especially under SIP operation, ensure that the oil is mixed within the cylinder before the piston reaches top dead center.

[0168] By controlling the type, quantity, and timing of the selected lubricant, a variety of injection sequences are possible, such as combinations of at least two of the following: during a single injection cycle, - Perform one or more injections below the piston. - One or more injections are performed on the piston surface. - One or more injections are made above the piston.

[0169] For various types of spraying, the choice of lubricant or multiple lubricants (and possibly additives) can also be diverse.

[0170] For example, the actuator is an electronically controlled actuator and is electrically connected to the controller, receiving an injection phase signal from the controller that indicates the timing of injection. During the injection phase, the controller sends an electronic signal to each injector to initiate the lubricant injection phase. Consequently, the valve system opens, allowing the corresponding lubricant to flow through the flow path and be injected into the cylinder. At the end of the injection phase, the electronic signal from the controller to the injector changes, causing the valve system to close the lubricant injection and return to an unloaded state.

[0171] In a specific embodiment, the actuator includes an electric solenoid device having a fixed solenoid portion and a movable solenoid portion. A valve system is connected to the movable solenoid portion for actuation by the actuator when the solenoid is electrically excited, wherein the solenoid is configured to be excited by a jetting phase signal from the controller.

[0172] The term “solenoid coil” should be understood as “at least one solenoid coil”, as more than one coil may be used, and in some cases it is advantageous to use two or three coils.

[0173] The term "signal" in the controller is used here to refer to the current flowing from the controller 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 drive direction of an electromechanical actuator, the current direction is switched to the opposite direction. However, alternatively, the injector may include an electrical switch in which the controller signal is turned on, causing a sufficiently strong current to flow to the actuator to drive it. In the latter case, the signal line from the controller to the electrical switch can be implemented with very fine wiring. Alternatively, the term "signal" can also refer to a wireless signal.

[0174] Alternatively, the actuator may be a hydraulic or pneumatic actuator. Such a hydraulic or pneumatic actuator in the injector may also be electrically controlled. For example, an electrical signal from the controller to the injector causes the electromechanical actuator valve of the injector to open, allowing hydraulic or pneumatic flow to enter the actuator, thereby hydraulically or pneumatically actuating the valve system. Alternatively, an electrical signal from the controller to the injector causes the electromechanical actuator valve to open, allowing hydraulic or pneumatic flow to enter the actuator to drive the actuator itself, which then mechanically drives the valve system.

[0175] In some embodiments, the valve system is configured to select only one injector from a plurality of injectors at a time for supplying lubricant and for its spraying. In some embodiments, alternatively or additionally, the valve system is configured to select more than one injector from a plurality of injectors at a time for supplying lubricant and for its spraying, so as to spray multiple lubricants or combinations of lubricants and additives simultaneously.

[0176] In some embodiments, the injector has more than one nozzle, and various lubricants and additives can be injected into the cylinder through different nozzles of the injector. In other embodiments, various lubricants and additives are injected into the cylinder through a single nozzle and may be mixed inside the injector before exiting from the nozzle orifice.

[0177] In practical embodiments, the injector includes a base and a rigid (optionally cylindrical) flow chamber that rigidly connects the base to the nozzle, allowing the nozzle to be fixed inside the cylinder wall when the base is fixed to the cylinder wall. Since the base is located at the opposite end of the flow chamber relative to the nozzle, it is typically located on or outside the cylinder wall. For example, the injector includes a flange located at the base for mounting to the outer surface of the cylinder wall. Alternatively, to mount the injector inside the cylinder wall, the injector includes a flange surrounding the flow chamber. For example, the flange is bolted to the cylinder wall.

[0178] Advantageously, the base includes first and second inlets and possibly other inlets. The flow chamber is hollow and contains a flow path for lubricant to flow from the lubricant inlet through the flow chamber to the nozzle for injection into the cylinder. Optionally, the valve member is located in the flow chamber or the base.

[0179] For example, when the injector is mounted on the cylinder wall, the actuator is located outside the cylinder wall. Alternatively, it is fixed to a base.

[0180] In practice, the actuator receives a injection phase signal, causing the actuator to move the valve component to the injection phase position or direction according to the injection phase signal, which in turn opens the flow path to inject lubricant into the cylinder.

[0181] For example, the actuator is mechanically connected to the selector valve member via an actuator extension, which drives the valve member. This is advantageous if the valve member is located in the flow chamber and thus inside the cylinder wall, while the actuator is located outside the cylinder wall. In this embodiment, operation involves moving the valve member using the actuator extension via the actuator.

[0182] Outlet valve system Optionally, each injector includes an outlet valve system located at the nozzle, configured to open during the injection phase once the pressure at the outlet valve system rises above a predetermined limit, allowing lubricant to flow into the nozzle orifice, and to close after the injection phase when the pressure drops. The outlet valve system closes due to cylinder back pressure, while also preventing lubricant from entering the cylinder during the no-load phase between injection phases. Furthermore, the outlet valve system helps to shorten the closing time after injection, increasing the accuracy of the timing and volume of the injected lubricant.

[0183] In these embodiments, the injector includes a lubricant flow path from a lubricant inlet through a valve system to an outlet valve system, such that lubricant flows from the lubricant inlet through the valve system and the outlet valve system and exits the injector at a nozzle orifice. The valve system is configured as part of the injector, located upstream of the nozzle and optionally spaced apart from the nozzle. Optionally, the valve system is located upstream of and spaced apart from the outlet valve system.

[0184] For example, an outlet valve system includes an outlet check valve. In the outlet check valve, an outlet valve member (e.g., a ball, ellipse, plate, or cylinder) is pre-pressed onto an outlet valve seat by an outlet valve spring. Once pressurized lubricant is supplied to the flow chamber upstream of the outlet valve system, the pre-pressurization force of the spring is counteracted by the lubricant pressure. If the pressure exceeds the spring force, the outlet valve member displaces from its outlet valve seat, and the outlet check valve opens, allowing lubricant to be injected into the cylinder through a nozzle orifice. For example, the outlet valve spring acts on the outlet valve member in a direction away from the nozzle orifice, but the opposite movement is also possible.

[0185] For example, to lubricate an engine, the method includes sending an electronic control signal from a controller to the injector, and causing the injector to open the valve system so that lubricant flows from the lubricant supply conduit through the lubricant inlet, through the valve system, and into a conduit that fluidly connects the valve system to the outlet valve system.

[0186] It should be noted that the lubricant pressure in the lubricant supply conduit is higher than a predetermined limit that determines whether the outlet valve system opens. This ensures that the lubricant supply conduit provides lubricant at a pressure high enough to open the outlet valve system during the injection phase. Therefore, lubricant flows through the conduit between the valve system and the outlet valve system, causing a pressure rise at the outlet valve system, which opens the outlet valve system, allowing lubricant to flow from the conduit to the nozzle orifice, where it is then injected into the cylinder. At the end of the lubrication cycle, the controller's electrical signal is changed, causing the valve system to close the lubricant supply from the lubricant inlet to the nozzle orifice again. The pressure in the conduit drops again, and the outlet valve system closes.

[0187] In these embodiments, the injector has at least two valve systems. The valve systems are regulated under the control of a controller, for example, via an electrical signal from the controller, while the outlet valve system is activated only when the lubricant pressure increases at the outlet valve system. Once the valve system opens, pressurized lubricant flows from the lubricant supply conduit to the outlet valve system. There is no mechanical connection linking the movable parts of the valve systems to the movable parts of the outlet valve system. The connection between the opening and closing of these systems is accomplished solely through the flow of lubricant from the valve systems to the outlet valve system.

[0188] Optional details for valves and actuators In some practical embodiments, the valve system includes a movable, actuator-driven valve member configured to move from an unloaded phase position (where the valve member blocks the flow path during the unloaded phase) to an injection phase position (where the valve member opens the flow path during the injection phase to allow lubricant to flow through the flow path). Advantageously, the valve member is pre-compressed by a valve spring near the unloaded phase position.

[0189] In some embodiments, in order to drive the movable valve member, the injector includes a movable and actuator-driven rigid actuator extension member that connects the actuator to the valve system and is used by the actuator to shift or rotate the valve member from an unloaded phase position (where the valve member blocks the flow path) to an injection phase position (where the valve member opens the flow path to allow lubricant to flow through the flow path, thereby injecting lubricant into the cylinder during the injection phase).

[0190] Optionally, the rigid actuator extension driven by the actuator is a push-pull member for selectively pulling or pushing the valve member during injection. Alternatively, the actuator extension is a rotating member for transmitting driving force from the rotary actuator, for example, selectively along one direction or another.

[0191] In some embodiments, the actuator is an electrically controlled actuator, such as an electromechanical actuator. Optionally, the actuator includes an electric solenoid device having a fixed solenoid portion and a movable solenoid portion, wherein an actuator extension member is connected to the movable solenoid portion for being driven by the actuator when the solenoid is electrically actuated, wherein the solenoid is configured to be actuated by a jetting phase signal from the controller.

[0192] For example, the valve system includes a linear actuator for driving an actuator extension. In this case, the actuator extension is connected to the actuator, such as a device connected to a solenoid plunger and a solenoid coil, for driving the actuator extension, such as a push-pull member, to open the flow of fluid from the lubricant inlet when the actuator is electrically activated. Optionally, the actuator extension is connected to the solenoid plunger, while the solenoid coil is fixed in the injector. Alternatively, the actuator extension is connected to the solenoid coil, which is movable together with the actuator extension.

[0193] Alternatively, piezoelectric elements can be used to drive valve components. These elements are electrically or wirelessly connected to a controller so that the controller can control when to contract or expand.

[0194] In some specific embodiments, the valve component is cylindrical and includes a fixed valve component, which in turn includes a corresponding cylindrical bushing. The cylindrical valve component is disposed within the bushing and is configured to shift along the longitudinal axis of the bushing or to rotate about the longitudinal axis of the bushing.

[0195] The term "cylindrical bushing" is used to describe a bushing that has a cylindrical hollow, typically but not necessarily with a circular cross-section. The cylindrical valve member is tightly fitted into the cylindrical hollow of the bushing, such that no lubricant can flow between the cylindrical valve member and the cylindrical bushing, except for a very small amount that may lubricate the valve member only inside the bushing, which is negligible compared to the amount of lubricant injected into the cylinder.

[0196] System advantages The system described in this article has many advantages.

[0197] By incorporating a valve system within the injector, along with an optional outlet valve system, the mass of the movable parts that must be moved during operation is reduced. Compared to existing systems, this lighter weight reduces the reaction time of the movable objects, thus implying improved reaction speed and precision in timing and quantity.

[0198] Because the length of the injector is typically several times (e.g., twice) the thickness of the cylinder wall in such large engines and extends through an opening in the cylinder wall, the distance from the valve system to the nozzle orifice is typically about the thickness of the cylinder wall or even less. For example, the distance from the valve system to the nozzle orifice is less than 20 centimeters or even less than 10 centimeters, which is much shorter than the several meters between the valve and the nozzle in the prior art. This means that the distance from the valve system to the nozzle outlet is extremely short in comparison, and the valve system has a correspondingly short reaction time and precision.

[0199] Because the valve system is located inside the injector housing and close to the nozzle, the injector has a short reaction time, thus enabling highly precise injection timing and duration, which translates into injection volume. Due to this precise timing and rapid reaction time, lubricant injection in a single injection cycle can be completed through multiple partial injections. Since the aforementioned injector has only a short and rigid flow path from the valve system to the nozzle (including, for example, the outlet valve system), the uncertainties and inaccuracies in injection volume and timing are minimized by avoiding the minor compression and expansion of oil in relatively long conduits and the expansion of the conduits themselves.

[0200] For example, secondary injection can be performed during the time span before the engine piston passes the injector, so that the two types of lubricant can mix in the cylinder, especially when using the SIP principle.

[0201] This system may require only a single lubricant line to the lubricant injector, as there is no need for a return line. This minimizes installation costs and workload, and reduces the risk of malfunction. This is especially true for large engines that require several meters of return line. Furthermore, it avoids inaccuracies in timing and volume due to potential dead volume in the lubricant return line when the valve is closed.

[0202] Due to the outlet valve system with a one-way valve, the injector stably resists high pressure from the cylinder. In cases where the outlet valve system includes a one-way valve at or inside the nozzle, and this one-way valve comprises a valve member (e.g., a ball) that is spring-loaded against a valve seat, high robustness to failure has been observed. These systems are simple and have minimal risk of clogging. Furthermore, the valve seat tends to be self-cleaning and experiences virtually no uneven wear, especially for ball-type valve members, thus providing high and long-term reliability. Therefore, the injector is simple, reliable, fast, precise, and easy to construct using standard parts, resulting in low production costs.

[0203] In conclusion, the unique valve system operates quickly due to its lightweight components. Furthermore, the relatively simple component structure translates to low production costs. In addition to these advantages, the valve system is reliable, robust, and has a low risk of clogging. Because the components withstand relatively small pressure loads, the valve system also has a long service life.

[0204] Optional parameters For example, the injector includes a nozzle with a nozzle orifice, which has a diameter D if the nozzle is circular, or an equivalent diameter D if the nozzle is not circular, which is twice the area of ​​the nozzle orifice divided by the square root of π; wherein the diameter D is at least 0.1 mm, and is configured to spray a mist of atomized droplets, also known as an oil mist.

[0205] The atomization of liquid droplets is crucial in spray lubrication. This atomization is particularly important in SIP (Single Injection Propulsion) lubrication, where the lubricant spray is repeatedly injected into the scavenging air inside the cylinder before passing the injector on its way to top dead center. In the scavenging air, the atomized droplets are diffused and distributed onto the cylinder walls, and due to the vortex motion of the scavenging air towards top dead center, the atomized droplets are propelled in that direction. The atomization of the spray is due to the pressurized lubricant at the nozzle in the lubricant injector. Typically, this high-pressure injection pressure is above 10 bar, between 25 and 100 bar. For example, it is in the range of 30 to 80 bar, optionally between 35 and 60 bar. The injection time is short, typically about 5–30 milliseconds (msec). However, the injection time can be adjusted to 1 millisecond or even less, for example, as low as 0.1 milliseconds. Therefore, even an inaccuracy of just a few milliseconds can harmfully alter the injection profile, thus requiring high precision, as mentioned above, such as 0.1 milliseconds.

[0206] Furthermore, viscosity affects atomization. Lubricants used in marine engines are typically around 40... It has a typical kinematic viscosity of about 220 cSt at C, and at 100 At C, it is 20 cSt, which translates to 202 to 37 mPa. The dynamic viscosity is between 40 and 100 viscous. A useful example of a lubricant is the high-performance marine diesel engine cylinder oil ExxonMobil® Mobilgard™ 570VS (or the phased-out 560VS). Other useful lubricants for marine engines include other Mobilgard™ oils and Castrol® Cyltech oils. Commonly used lubricants for marine engines have a dynamic viscosity between 40 and 100 viscous. The viscosity profiles are approximately the same within the C range, for example, when the nozzle orifice diameter is 0.1-0.8 mm, and the lubricant pressure at the nozzle orifice is 30-80 bar, and the temperature is 30-100°C. C or 40-100 Within the C range, it is useful for atomization. See also the published article on this topic: Rathesan Ravendran, Peter Jensen, Jesper de Claville Christiansen, Benny Endelt, Erik AppelJensen, (2017) “Rheological behaviour of lubrication oils used in two-stroke marine engines”, Industrial Lubrication and Tribology, Vol. 69 Issue: 5, pp. 750-753. https: / / doi.org / 10.1108 / ILT-03-2016-0075 .

[0207] The motion of an oil droplet is governed by the relationship between the droplet's momentum and the forces affecting the droplet.

[0208] The momentum of a droplet is controlled by its velocity and mass, i.e.

[0209] Where P is momentum and m is the mass of the droplet. It is the velocity of the droplet.

[0210] The force (F) affecting the droplet is described as follows:

[0211] The two most important forces are buoyancy:

[0212] and resistance:

[0213] Here, ρ is density, g is gravitational acceleration, and V is volume. It is the drag coefficient. Here, f is the velocity, and A is the cross-sectional area of ​​the droplet. The subscript f refers to the fluid surrounding the droplet, and the subscript p refers to the droplet itself. The droplet behaves according to Newton's second law:

[0214] As can be seen from (15), the force alters the droplet velocity, thus changing their momentum. When the ship's engine changes its load, it alters the buoyancy and drag. Changes in engine load also alter the thrust. It alters the relationship between the forces affecting the droplet and the droplet's momentum, thus changing the droplet's motion (see (15)).

[0215] To obtain a favorable relationship between droplet momentum and the forces influencing them, the droplet momentum must be affected. This can be achieved by changing any of the following: • Oil temperature (i.e., viscosity) • Pressure in common rail • The geometry of the nozzle, such as the rounded corners at the inlet from the sac-like orifice to the spray orifice.

[0216] Furthermore, it can be seen from the above equation (15) that if the smaller droplet has the same initial velocity ejected from the nozzle as the larger droplet and is roughly circular, the smaller droplet will be more affected by the scavenging air in the cylinder than the larger droplet.

[0217] In addition to affecting the momentum of the droplets, the position of the oil droplets reaching the cylinder wall can also be controlled by changing the injection angle in the cylinder.

[0218] With this information, the movement of droplets in the scavenging air can be influenced, and ultimately, the position where they eventually reach the cylinder wall.

[0219] The pressure change measured by the pressure gauge in the injector is used to calculate the volume flowing through the nozzle in experimental tests.

[0220] These experimental tests show that there is a good consistency between the amount calculated based on the pressure measurement and the actual amount sprayed.

[0221] The injection rate of SIP lubricant for cylinder lubrication, as tested by the Bosch injection rate method, yields the following results: • The mass flow rate increases within approximately 1 millisecond until cavitation in the nozzle begins to block the flow.

[0222] When blockage begins, cavitation becomes intense enough to atomize the oil. This results in rapid spray formation, which is an advantage of using SIP for lubrication.

[0223] • The functional relationship between injection volume and ramp time is approximately a straight line, making it easier to accurately measure the correct amount of lubricant oil mass flow rate, and the oil rise and fall time is close to 1 millisecond.

[0224] • Throughout almost the entire ramp time testing range, for the high-viscosity fluid used, called HydraWay HVXA15, which has characteristics similar to heated cylinder lubricating oil, the Bosch injection rate method was able to predict the delivery volume of a single injection with a deviation from the weighing rate within approximately 5%. [Ravendran R, Jensen P, De ClavilleChristiansen 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].

[0225] Each injection can precisely measure milligrams or more of lubricating oil, and the rapid rise and fall times of the mass flow rate open up new possibilities for lubrication strategies. These include the ability to inject multiple times during the piston stroke and deliver the required amount each time.

[0226] Brief description of the attached figures The present invention will be explained in more detail with reference to the accompanying drawings, wherein... Figure 1 This is a partial schematic diagram of a cylinder in a first embodiment of the engine according to the present invention. Figure 2 yes Figure 1 The illustration shows an embodiment of the injector. Figure 3 These are charts showing experimental data and comparisons with literature. Figure 4 It is shown Figure 2 A schematic diagram of another embodiment of the injector nozzle shown. Figure 5 This corresponds to another embodiment of the engine according to the present invention. Figure 1 A schematic diagram of the cylinder section. Figure 6 yes Figure 5 A schematic diagram of an embodiment of the injector shown. Figure 7 yes Figure 6 An enlarged cross-sectional view of the inlet valve housing of the injector shown. Figure 8This corresponds to another embodiment of the engine according to the present invention. Figure 1 A schematic diagram of the cylinder section. Figure 9 These are charts showing experimental data and comparisons with literature. Figure 10 It is a graph showing the relationship between time and mass flow rate. Figure 11 The initial droplet size distribution is shown. Figure 12 The second initial droplet size distribution is shown. Figure 13 The third initial droplet size distribution is shown. Figure 14 Is for Figure 13 The diagram shows the distribution of droplets that did not reach the cylinder wall. Figure 15 This is a partial schematic diagram of a common rail system, including a common rail and high-pressure devices with pumps and valves. Figure 16 This is a schematic diagram of another embodiment of the injector used in the system according to the present invention, illustrated in the closed position, and Figure 17 yes Figure 13 The diagram shows the injector in the open position.

[0227] Detailed Implementation / Preferred Embodiments Figure 1 Half of a cylinder 1 of a large, low-speed two-stroke engine (e.g., a marine diesel engine) is shown. Cylinder 1 includes a cylinder liner 2 inside a cylinder wall 3. Multiple injectors 4 are provided within the cylinder wall 3 for injecting lubricant into the cylinder 1. As shown, the injectors 4 are distributed circumferentially, with the angular distance between adjacent injectors 4 being equal, although this is not strictly necessary. Furthermore, a circumferential arrangement is not required, as an axially offset arrangement of the injectors is also feasible, for example, every two injectors are offset relative to adjacent injectors towards the piston's top dead center (TDC).

[0228] Each injector 4 has a nozzle 5 with a nozzle orifice 5', from which a fine atomized spray 8 containing tiny droplets 7 is ejected into the cylinder 1 under high pressure.

[0229] For example, the diameter of the nozzle orifice 5' is between 0.1 and 0.8 mm, for example, between 0.2 and 0.5 mm, at a pressure of 10-100 bar, for example, 25 to 100 bar, optionally 30 to 80 bar or even 50 to 80 bar, atomizing the lubricant into a fine spray 8, which contrasts with a compact lubricant jet. The scavenging vortex 14 in the cylinder 1 delivers and presses the spray 8 toward the cylinder liner 2, thereby achieving a uniform distribution of lubricating oil on the cylinder liner 2. This lubrication system is known in the field as the vortex jet principle (SIP).

[0230] However, other principles have also been envisioned for improved lubrication systems, such as injectors that spray jets or mists directly toward the cylinder liner or piston ring assembly.

[0231] Optionally, the cylinder liner 2 is provided with a free cutout 6 to provide sufficient space for the spray 8 or jet of the injector 4.

[0232] In addition to the lubricant supply conduit 9 (which serves as a common supply conduit), the injector 4 is also connected to the controller 11 via the pressure control conduit 10. The lubricant supply conduit 9 is used to supply lubricant for injection. The pressure control conduit 10 supplies high-pressure oil to activate the pumping system inside the injector 4, which will be explained in more detail below.

[0233] The pressure in the pressure control conduit 10 is higher than the pressure in the lubricant supply conduit 9. Typically, the lubricant pressure in the lubricant supply conduit 9 is in the range of 1-15 bar, for example, in the range of 5-15 bar, while the oil pressure in the pressure control conduit 10 is in the range of 20-100 bar, for example, in the range of 30-80 bar, optionally 50-80 bar.

[0234] The controller 11 is connected to a supply conduit 12 and a return conduit 13. The supply conduit 12 is used to receive lubricant from a lubricant supply source 25 (including an oil pump), and the return conduit 13 is used for the return of lubricant, typically back to the oil tank, and optionally for lubricant recirculation. The lubricant pressure in the supply conduit 12 is higher than the pressure in the return conduit 13, for example, at least twice as high.

[0235] The controller 11 supplies lubricating oil to the injector 4 in the form of precisely timed pulses, synchronized with the piston movement in the engine cylinder 1. For example, for synchronization, the controller system 11 is electrically connected to a computer 11' via wired or wireless means, which controls the components in the controller 11 to ensure lubrication supply. Possibly, the computer 11' is part of the controller 11, for example, housed within a single housing along with other components of the controller 11. Optionally, the computer monitors parameters of the engine's actual state and motion, such as speed, load, and crankshaft position, the latter revealing the piston position in the cylinder.

[0236] Figure 2Injector 4 is shown.

[0237] The injector 4 includes an injector housing 4' having an injector base 21 having a lubricant inlet port 4A and a pressure port 4B. The lubricant inlet port 4A is used to receive lubricant from the lubricant supply conduit 9, and the pressure port 4B is connected to a pressure control conduit 10 for causing the injector 4 to spray lubricant.

[0238] The flow chamber 16, as part of the injector housing 4', holds the nozzle 5 relative to the injector base 21. In the illustrated embodiment, the flow chamber 16 is configured as a hollow rigid rod. The flow chamber 16 seals the injector base 21 by an O-ring 22 and presses it firmly against the injector base 21. A conduit 16' is disposed inside the flow chamber 16 as a hollow channel, extending from the rear to the front of the flow chamber 16. The conduit 16' communicates with the lubricant inlet port 4A and the nozzle 5 through the rear chamber 16A, the first intermediate chamber 16B, the second intermediate chamber 16C, and the front chamber 16D.

[0239] The injector 4 also includes an outlet valve system 15 for regulating the lubricant distributed through the nozzle orifice 5'. The outlet valve system 15 only opens to inject lubricant into the engine cylinder 1 when the pressure at the outlet valve system 15 exceeds a predetermined pressure. Figure 2 In one embodiment, the outlet valve system 15 is exemplified as part of the nozzle 5, although this is not strictly necessary.

[0240] The outlet valve system 15 includes an outlet check valve 17. In the outlet check valve 17, an outlet valve member 18 (e.g., a ball) is preloaded onto an outlet valve seat 19 by the spring load of an outlet valve spring 20. When pressurized lubricant is supplied in the pre-chamber 16D, the preload force of the outlet valve spring 20 is offset by the lubricant pressure. When the pressure becomes higher than the spring force, the outlet valve member 18 displaces from its outlet valve seat 19, and the outlet check valve 17 opens to inject lubricant into the cylinder 1 through the nozzle orifice 5'.

[0241] As shown in the example, the outlet valve spring 20 acts on the valve member 18 in a direction away from the nozzle orifice 5'. However, the direction of the force exerted by the outlet valve spring 20 relative to the nozzle orifice 5' on the outlet valve member 18 can be configured differently, as long as the one-way valve 17 closes the lubricant supply to the nozzle orifice 5' under no-load conditions between injection phases. The closure of the one-way valve 17 under no-load conditions prevents lubricant from unintentionally flowing from the front chamber 16D into the cylinder 1 through the nozzle orifice 5' between injection phases.

[0242] Rear chamber 16A communicates with inlet port 4A for receiving lubricant from lubricant supply conduit 9. Rear chamber 16A communicates with first intermediate chamber 16B via rear channel 23A. First intermediate chamber 16B communicates with second intermediate chamber 16C via intermediate channel 23B, which is a cylindrical opening surrounding actuator member 28, as will be explained below. Second intermediate chamber 16C communicates with front chamber 16D via front channel 23C.

[0243] For convenience, the term "forward movement" is used to refer to movement toward the nozzle orifice 5', while movement in the opposite direction away from the nozzle orifice 5' is called "backward movement".

[0244] The pre-chamber 16D is emptied through the nozzle orifice 5' by the forward movement of the reciprocating plunger member 29, which is resisted by the spring load of the helical plunger spring 29B in the second intermediate chamber 16C. The plunger member 29 includes a channel inlet 24 leading to a forward passage 23C, which is an internal passage of the plunger member 29, for example, located at the center of the plunger member 29, as shown. During the forward movement of the plunger member 29, the forward passage 23C is closed by a one-way plunger valve 26. In the illustrated embodiment, an example of the one-way plunger valve 26 is a plunger ball 26A included in a plunger valve seat 26B, which is pre-pressed onto the seat by a plunger valve spring 26C.

[0245] The forward movement of the plunger assembly 29 is achieved by the forward movement of the actuator assembly 28, which presses against the head 29A of the plunger assembly 29. The actuator assembly 28 is pre-compressed in the rearward direction by the helical actuator spring 28A in the first intermediate chamber 16B.

[0246] In the illustrated example embodiment, actuator component 28 and plunger component 29 are separate elements; however, they can also be combined into a single actuator plunger, for example, with actuator component 28 at one end of a single element and plunger component 29 at the other end.

[0247] The forward movement of the actuator component 28 is achieved by pressurized lubricant at the pressure control port 4B, which presses against the rear part 28B of the actuator component 28 in the pressure chamber 27, causing them to move together.

[0248] The function of injector 4 is explained in more detail below. When pressurized oil is supplied to pressure control port 4B, for example in the pressure range of 20-100 bar, the pressurized oil expands the volume of pressure chamber 27 by pushing the rear portion 28B of actuator member 28 and moving actuator member 28 forward. As actuator member 28 presses against the head 29A of plunger member 29, plunger member 29 moves forward together with actuator member 28, resisting the forces of actuator spring 28A and plunger spring 29B. The forward movement of plunger member acts on the lubricant in front chamber 16D. As check valve 26 prevents lubricant in front chamber 16D from escaping rearward, the lubricant in front chamber 16D is pressurized to a predetermined pressure limit, at which the outlet valve system 15 with check valve 17 opens to inject lubricant from front chamber 16D into cylinder 1 through nozzle orifice 5'.

[0249] At the end of the injection phase, oil is discharged from pressure control port 4B, causing actuator spring 28A and plunger spring 29B to push actuator component 28 and plunger component 29 back away from nozzle 5. The rearward movement of plunger component 29 reduces the pressure in front chamber 16D, opening one-way plunger valve 26 due to the pressure drop in front chamber 16D. This, in turn, closes one-way outlet valve 17 and draws lubricant from second intermediate chamber 16C into front chamber 16D through front passage 23C. Thus, one-way plunger valve 26 acts as a suction valve, as the pressure drop in front chamber 16D causes it to draw in lubricant to replenish the front chamber 16D. During the return movement of actuator component 28 and plunger component 29, lubricant is replenished from first intermediate chamber 16B to second intermediate chamber 16C, which is then filled by rear chamber 16A, which receives lubricant through lubricant inlet port 4A.

[0250] For proper operation, lubricant is supplied at a constant pressure from lubricant supply conduit 9 to lubricant inlet port 4a, and pressurized oil is supplied from pressure control conduit 10 to pressure control port 4B for intermittent use in the injection cycle. The pressure at pressure control port 4B increases during the injection phase and decreases during the no-load state between injection phases.

[0251] If, under no-load conditions, the forward force exerted by the oil pressure in pressure chamber 27 on actuator component 28 is less than the resultant backward force of actuator spring 28A and plunger spring 29B, then actuator component 28 and plunger component 29 will completely return to their most rearmost feasible position, i.e. Figure 2 The position indicated in the middle. Thus, the full stroke of the plunger assembly is achieved by intermittently changing the oil pressure at the pressure control port 4B between full pressure and lower pressure (e.g., the lubricant pressure in the lubricant supply conduit 9 or even lower than the lubricant pressure in the lubricant supply conduit 9).

[0252] However, the actuator assembly 28 and plunger assembly 29 can be kept offset relative to their rearmost position by adjusting the pressure at the pressure control port 4B and pressure chamber 27 to an offset pressure level. This offset pressure level applies a force to the actuators such that springs 28A and 29B do not fully extend during the rearward movement of actuator assembly 28 and plunger assembly 29, but remain slightly compressed. This is possible because the force of springs 28A and 29B varies with the compression length in a roughly linear relationship with the displacement of the actuator assembly from its rearmost position. The offset pressure level is less than the pressure level required to open the one-way valve 17 for injection.

[0253] In principle, lubricant can be supplied to injector 4 from one lubricant source at inlet port 4A, or pressurized oil or other pressurized fluid can be supplied from a completely different source. However, usually for simplicity and convenience, the pressurized oil at pressure control port 4B comes from the same source as the lubricant at inlet port 4A, but at a higher pressure, for example, by using a booster.

[0254] As can be seen from the example above, the lubricant supply conduit 9 is connected to the return conduit 13. This is also... Figure 1 The solid line 9'' is shown in the center, extending to connect to the supply conduit 9. If the controller 11 is an additional unit, it will have at least four conduit connectors.

[0255] However, this is not always necessary. Optionally, the controller 11 includes a return outlet line connected to the return conduit 13. In the latter case, the return conduit 13 communicates directly with the supply conduits 9' and 9'. This embodiment... Figure 1 The line 9' is shown as an alternative dashed line, which extends to connect to the supply conduit 9. In this case, the return conduit 13, as an extension of the supply conduits 9 and 9', supplies lubricant directly to the lubricant inlet port 4A of the injector 4 for injection into the cylinder, and bypasses the controller 11.

[0256] The following values ​​are non-limiting illustrative examples of feasible operating pressures. The pressure in the return conduit 13 and supply conduit 9 is 10 bar. The pressure in the supply conduit 12 is 40 bar. The outlet valve 15 opens at 37 bar, allowing lubricant to be injected at 37 bar. Springs 28A and 29B are configured to fully push the plunger member 29 and actuator member 28 back to their rearmost position when the pressure at the pressure control port 4B is 10 bar under no-load conditions between injection phases. The pressure valve is adjustable to a pressure between 10 and 30 bar, for example, 20 bar, well below the injection pressure of 37 bar, but high enough to provide a sufficiently high pressure in the pressure chamber 27 so that the actuator member 28 cannot fully return to its rearmost position, but instead remains at a distance from it. This distance is adjusted by regulating the pressure within the range of 10-30 bar, thereby regulating the injection volume in the pre-chamber 16D, because the more the plunger member 29 deviates from its rearmost position at the start of the injection phase, the less forward movement occurs during the injection phase.

[0257] Optionally, the injection volume is controlled by a flow meter inserted into the supply conduit 9, whether for the injector group or for each individual injector 4. The flow meter measures the flow rate (mass and / or volume) and is then used to control the normal operation of the injectors.

[0258] The injection system with the aforementioned injector 4 and controller 11 is easy to install and replace. It is a relatively low-cost technical solution, yet robust and stable. In particular, the injection volume can be precisely adjusted. Furthermore, the system does not include wiring to and from the injector 4, making it highly heat-resistant, as wires would likely have insulation that would melt when heated.

[0259] The above-described embodiment has been disclosed in WO2019 / 114905. However, this engine differs in that it includes a pressure gauge 35. The pressure gauge may also be referred to as a pressure sensor. This pressure gauge 35 is used to measure the pressure in the lubricant supply conduit 9 (a common rail for supplying lubricant to the injector 4).

[0260] exist Figure 2 The diagram illustrates one pressure gauge 35 for each injector; however, in some practical embodiments of the system, fewer pressure gauges may be used. In some embodiments, only one pressure gauge is used for the lubricant supply conduit 9.

[0261] The signal from the pressure gauge regarding the actual pressure in the lubricant supply conduit 9 is then transmitted to the controller and used to calculate the desired pressure based on the engine load conditions, which is obtained by controlling the high-pressure pump in the lubricant supply source.

[0262] Alternatively, the high-pressure pump may be non-adjustable. In this case, the desired pressure in the lubricant supply conduit 9 is obtained by a control setting connected to the high-pressure pump and a valve used to connect the high-pressure pump to the lubricant supply conduit 9.

[0263] Figure 5 Half of a cylinder 1 of a large, low-speed two-stroke engine (e.g., a marine diesel engine) is shown. Cylinder 1 includes a cylinder liner 2 inside a cylinder wall 3. Within the cylinder wall 3, a plurality of injectors 4 are provided for injecting lubricant into the cylinder 1. As shown, the injectors 4 are distributed circumferentially, with the angular distance between adjacent injectors 4 being equal, although this is not strictly necessary. Furthermore, a circumferential arrangement is not required, as it is also feasible to arrange the injectors axially offset, for example, with each pair of injectors offset relative to adjacent injectors towards the piston's top dead center (TDC).

[0264] Each injector 4 has a nozzle 5 with a nozzle orifice 5', from which a fine atomized spray 8 is ejected into the cylinder 1 under high pressure.

[0265] For example, the diameter of the nozzle orifice 5' is between 0.1 and 0.8 mm, for example, between 0.2 and 0.5 mm, at a pressure of 10-100 bar, for example, 25 to 100 bar, optionally 30 to 80 bar or even 50 to 80 bar, atomizing the lubricant into a fine spray 8, which contrasts with a compact lubricant jet. The scavenging vortex 14 in the cylinder 1 delivers and presses the spray 8 onto the cylinder liner 2, thereby achieving a uniform distribution of lubricating oil on the cylinder liner 2. This lubrication system is known in the field as the vortex jet principle (SIP).

[0266] However, other principles have been envisioned in conjunction with improved lubrication systems, such as injectors that spray jets directly onto the cylinder liners or jets or sprays directed at the piston ring assembly.

[0267] Optionally, the cylinder liner 2 is provided with a free cutout 6 to provide sufficient space for the spray 8 or jet of the injector 4.

[0268] The injector 4 receives lubricating oil from a lubricating oil supply source 25 via a lubricating oil supply conduit 9 (as a common supply conduit), the lubricating oil supply source 25 including a lubricating oil pump that boosts the lubricating oil pressure to a sufficient level. For example, the pressure in the supply conduit 9 is in the range of 10 bar to 400 bar, preferably in the range of 25 to 100 bar, and optionally 30 to 80 bar, which is the typical pressure range for spray injectors (such as SIP injectors).

[0269] The injector 4 is provided with an electrical connector 110', which communicates electrically with the controller 11 via a cable 110. As previously mentioned, the injector can alternatively communicate wirelessly with the controller 11. The controller 11 sends an electrical control signal to the injector 4 to control the injector 4 to spray lubricant through the nozzle 5. As shown, one cable 110 is provided for each injector 4, which allows for individual control of the spraying of the corresponding injector. However, a single cable 110 can also be provided from the controller 11 to all injectors 4, so that all injectors 4 spray simultaneously when they receive an electrical control signal through a single cable. Alternatively, a single cable 110 can be provided from the controller 11 to subgroups of injectors, such as subgroups of 2, 3, 4, 5, or 6 injectors, such that the first subgroup is controlled by the controller via a first cable 10, and the second subgroup is controlled via a second cable 110. The number of cables and subgroups depends on the preferred configuration.

[0270] The above embodiment is disclosed in WO 2019 / 114905. However, the engine differs in that it includes a pressure gauge 35. The pressure gauge may also be referred to as a pressure sensor. This pressure gauge 35 is used to measure the pressure in the lubricant supply conduit 9 (a common rail for supplying lubricant to the injector 4).

[0271] exist Figure 5 The diagram shows a pressure gauge 35 for each injector; however, in some practical embodiments of the system, fewer pressure gauges may be used. In some embodiments, only one pressure gauge is used for the lubricant supply conduit 9.

[0272] Then, the signal of the actual pressure in the lubricant supply conduit 9 is transmitted from the pressure gauge to the controller and used to calculate the desired pressure based on the engine load condition, and obtain the pressure by controlling the high-pressure pump in the lubricant supply source.

[0273] The electronic control signals from controller 11 to injector 4 are provided in precisely timed pulses, synchronized with the movement of the engine piston in cylinder 1. For example, for synchronization, controller system 11 includes a computer 11' or is electrically connected to computer 11' via wired or wireless means, wherein computer 11' monitors parameters of the actual state and movement of the engine, such as speed, load, and crankshaft position, the latter of which reveals the position of the piston in the cylinder.

[0274] Figure 6 A schematic diagram of the principle of injector 4 is shown. Figure 6 This is an overview diagram of an example injector, with three different views: top view, end view, and cross-sectional side view.

[0275] The injector 4 includes a lubricant inlet port 112 for receiving lubricant from the lubricant supply conduit 9. The inlet port 112 is disposed in an inlet valve housing 121, which includes an inlet valve system 113 communicating with the inlet port 112 for regulating the amount of lubricant received from the lubricant supply conduit 9 during the lubrication phase. The injector 4 also includes an outlet valve system 115 for regulating the lubricant dispensed through the nozzle orifice 5'. A rigid flow chamber 116 connects the inlet valve system 113 and the outlet valve system 115 to allow lubricant flow to the nozzle 5. In the illustrated embodiment, the flow chamber 116 is configured as a hollow rigid rod. The flow chamber 116 seals the inlet valve housing 121 of the inlet valve system 113 by an O-ring 122 and is held pressed against the inlet valve housing 121 by a flange 123, which is fastened to the inlet valve housing 121 by bolts 124.

[0276] Figure 7 This is a magnified view of a portion of the inlet valve system.

[0277] Figure 7 The inlet valve system 113 is described in more detail. A one-way valve 125 is provided within the inlet valve housing 121, having an inlet valve member 126 pre-pressed onto an inlet valve seat 127 by an inlet valve spring 128. The inlet valve member 126 is exemplified as a sphere; however, different shapes, such as elliptical, conical, planar, or cylindrical, are also possible. When the inlet valve member 126 displaces from the inlet valve seat 127 against the force of the inlet valve spring 128, lubricant 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 a channel 129 on the other side of the inlet valve member 126. The lubricant flows from the channel 129 through a flow path 130 and into the hollow portion 116' of the flow chamber 116 to the outlet valve system, which has a general principle similar to that disclosed in WO2014 / 048438. The reference also provides additional technical details and an explanation of the operation of the injector presented in this paper, which will not be repeated here for convenience.

[0278] To displace the inlet valve component 126 (ball), a reciprocating push member 131 (e.g., a push rod) is provided in the channel 129. The push member 131 is not fixed to the inlet valve component 126, but rather to a reciprocating solenoid plunger 133, which is driven by a solenoid coil 132. The solenoid plunger 133 is retracted by a plunger spring 134 in an unloaded state. When the solenoid coil 132 is energized, the solenoid plunger 133 moves forward against the force of the plunger spring 134 until it abuts against the plunger stop 134. Due to the movement of the solenoid plunger 133, the push member (push rod) 131 pushes the inlet valve component (ball) 126 away from the inlet valve seat 127, thereby allowing lubricant to flow through the inlet check valve 125 and into the flow chamber 116.

[0279] In an advantageous embodiment, the push member (push rod) 131 retracts a distance from the inlet valve member (ball) 126 in an unloaded state, resulting in a free travel distance between the push member 131 and the inlet valve member 126. When the solenoid coil 132 is energized, the push member 131 is accelerated by the solenoid coil 132 over the free travel distance and then impacts the inlet valve member 126 after the initial acceleration. This results in a sudden displacement of the inlet valve member 126 from the inlet valve seat 127, compared to the case where the inlet valve member 126 moves together with the push member 131 during the first part of the acceleration. This rapid displacement of the inlet valve member 126 is advantageous for the precise timing of the start of lubricant injection into the cylinder 1. Optionally, the free travel distance can be adjusted by an adjustable screw 136 at the end of the solenoid plunger 133.

[0280] After the injection phase, the lubricant supply from the inlet port 112 to the nozzle 5 is stopped by cutting off the current to the solenoid coil 132. This causes the solenoid plunger 133 to be pushed back by the plunger spring 134, and the inlet valve member 126 to return to press against the inlet valve seat 127 for the no-load phase of the injection cycle.

[0281] The amount of lubricating oil is controlled by a flow meter, and the controller / computer allows the amount of lubricant to be adjusted to achieve cavitation in the shortest possible time.

[0282] Figure 8 Corresponding to Figure 1 This illustration shows another embodiment of one half of cylinder 1 in a large, low-speed two-stroke engine (e.g., a marine diesel engine). This embodiment includes an injector. The injector 4 may be an HJ Smartlube 4.0 electronic injector. The injector 4 is connected to a cylinder manifold with a flow meter 203. The cylinder manifold with the flow meter is connected to a controller 11 via communication line 211 for flow meter feedback signals. The controller 11 may be a cylinder local controller, connected to a central controller 208 via communication line 210.

[0283] A cylinder manifold with a flow meter 203 is connected to a pump unit 205. The pump unit 205 is connected to a lubricant supply source 25 via a supply conduit 12.

[0284] Pump unit 205 is connected to cylinder manifold (common rail) via pressurized oil supply line 214 to supply lubricating oil to injector 4.

[0285] The injector signal bus 212 connects the controller 11 and the injector, and is used to adjust the amount of lubricant and calibrate the injector.

[0286] Figure 15 A partial schematic diagram of a common rail system is shown, which includes a common rail, a high-pressure unit with pumps and valves.

[0287] If the pump is a variable displacement pump, this valve can be omitted.

[0288] The pump can be a variable displacement pump, used to adjust the pump speed, thereby regulating the output of the high-pressure pump to obtain the desired pressure in the lubricant supply conduit.

[0289] Alternatively, the pump is not a variable displacement pump. Instead, a valve is used that is located at the high-pressure pump and connects the high-pressure pump to the lubricant supply conduit. In this case, adjusting the valve is used to regulate the pressure in the lubricant supply conduit to the desired pressure.

[0290] This valve is connected to the pressure side and suction side of the high-pressure pump.

[0291] Therefore, since the valve is connected to the suction side of the high-pressure pump or to the return line of the lubricant supply source, the valve can release pressure.

[0292] The injector is preferably of the type described in general in WO 2012 / 126473. This injector is also known as the HansJensen Lubricators E-sip injector. This injector can be electromechanically driven, for example, in the form of a solenoid valve or a piezoelectric mechanical element.

[0293] Figure 16 and Figure 17 A schematic diagram of another embodiment of the injector 4 used in the system according to the present invention is shown, illustrated in the closed position and the open position, respectively.

[0294] Figure 16 and Figure 17 The injector shown is electromechanically driven and is in the form of a solenoid valve.

[0295] The injector is manufactured as a unit, such that the on / off valve is an electromechanical valve integrated within the injector for metering lubricating oil. The electromechanical on / off valve includes a spring-biased valve stem.

[0296] The lubricating oil is metered by activating the on / off valve in the injector. The activation action moves the valve stem of the on / off valve and injects the lubricating oil.

[0297] serial number 1 cylinder 2 Cylinder Liners 3. Cylinder wall 4. Injector 4' Injector housing 4A Oil Injector 4 Inlet Port 4B Oil Injector 4 Pressure Control Port 5 nozzles 5' Nozzle orifice 6. Free cuts in cylinder liners 7. Atomized spray from a single injector 4 8. Vortex Spray 9. Lubricant supply conduit 10 Pressure control catheter 11 Controller 11' Computer 12 Supply catheter 13. Reflux conduit 14. Swirls in the cylinder 15. Outlet valve system of injector 4 16 Flow chamber connecting inlet valve system 13 and outlet valve system 15 16' to the hollow portion of flow chamber 16 16A Rear Chamber 16B First Intermediate Room 16C Second Intermediate Chamber 16D Antechamber 17. Outlet check valve, example: outlet ball valve 18. Outlet valve component, example: ball. 19. Outlet valve seat 20 Outlet valve spring 21 Injector base 22 O-rings at the end of the flow chamber 23A The rear passage in actuator component 28 connects the rear chamber 16A and the first intermediate chamber 16B. 23B Intermediate passage between the first intermediate chamber 16A and the second intermediate chamber 16B 23C The front passage in the plunger assembly 29, between the second intermediate chamber 16B and the front chamber 16D. 24. Enter the passageway 23C from the front passage. 25 Lubricant Supply Sources 26-Plunger Check Valve 26A Piston Valve Ball 26B is a plunger valve seat, on which the plunger valve ball 26A is pre-pressed. 26C Piston valve spring, pre-compressed piston valve ball 26A abuts against piston valve seat 26B 27 Pressure chamber at rear 28B 28 Actuator component for actuating the head 29' of the plunger component 29. 28A Actuator spring acting rearward on actuator component 28 28B Rear part of actuator component 28 29. Plunger Components 29A Head of plunger component 29 29B Piston spring in the second intermediate chamber 16C 30 Switching valve 30A Switching Valve Inlet Port 30B Switching Valve Outlet Port 30C Switching Valve Return Port 31 Pressure valve 31A Pressure Valve Inlet Port 31B Pressure valve return port 31C Pressure regulator, for example, a pressure regulating member with spring load during the injection phase. Preload in pressure valve 31D 32 Switching Components 32A First switching closing element of switching component 32 32B The second switching closing element of switching component 32 Arrow 33 indicates the reciprocating motion of switching component 32. 34 Return outlet piping from controller 11 to return conduit 13 35 Flow Meter 36. Expected lubrication dosage 37. Calculated actual lubrication dosage 38. Signal from the flow meter 39 Control Signals 40 Uncalibrated injectors 41. Calibrated injector 112 Lubricant inlet port of injector 4 113 Inlet valve system of injector 4 114 Swirls in the cylinder 115 Injector 4's outlet valve system 116 Flow chamber connecting inlet valve system 113 and outlet valve system 115 116' to the hollow section of flow chamber 16 117 Outlet check valve, example is an outlet ball valve 118 Outlet valve component 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 flow chamber 123 Flange used to maintain the flow chamber 124 Bolts for securing flange 123 and flow chamber 16 to inlet valve body 121 125 Inlet check valve, example is an inlet ball valve 126 Inlet valve component, example is a ball. 127 Inlet Valve Seat 128 Inlet Valve Spring 129 Channel in the inlet valve system 130 Flow channel from channel 129 to the hollow portion 116' of flow chamber 16 131 A push member fixed to the solenoid plunger 133, an example of which is a push rod. 132 Solenoid Coil 133 Solenoid plunger in solenoid coil 131 134 Piston Spring 135 plunger stop 136 Adjustable screw for adjusting free travel distance 203 Cylinder manifold with flow meter 205 Pump Unit 208 Central Controller Communication lines between the 210 cylinder local controller and the central controller 211 Communication line for flowmeter feedback signal 212 Injector Signal Bus 214 Pressurized oil supply pipeline 215 Feedback control algorithm.

Claims

1. A large, low-speed, two-stroke engine, the engine comprising a cylinder (1) with a reciprocating piston and a system, the system comprising: - A lubricant supply source (25) includes a lubricant pump that increases the pressure of the lubricant to a lubricant pressure within the typical pressure range of the spray nozzle. - Multiple lubricant injectors (4) distributed along the periphery of the cylinder (1) are used to inject lubricant into the cylinder (1) at different positions on the periphery during the injection phase. - Lubricant supply conduit (9), connecting lubricant supply source (25) and lubricant injector (4). The engine also includes: - Controller (11), for controlling the amount and timing of lubricant injection from at least one lubricant injector (4), Each injector (4) includes: - An inlet port in fluid communication with the lubricant supply conduit (9) for receiving lubricant. - A nozzle (5) having a nozzle orifice (5') extending into the cylinder, configured to inject lubricant from the inlet port (4A) into the cylinder (1) during the injection phase. Its features are, The controller is configured to control and change the pressure in the lubricant 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.

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

3. The large low-speed two-stroke engine according to claim 1 or 2, characterized in that, The desired pressure is based on engine load.

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

5. The large low-speed two-stroke engine according to any one of claims 1-4, characterized in that, The engine also includes - A computer (11') connected to the controller, or alternatively - The mobile phone configured to communicate with the controller.

6. The large low-speed two-stroke engine according to any one of claims 1-5, characterized in that, Each injector also includes - An adjustable valve located at the nozzle is used to open and close the flow of lubricant to the nozzle orifice during the injection phase.

7. The large low-speed two-stroke engine according to any one of claims 1-6, characterized in that, Each injector is a SIP injector.

8. A method for lubricating a large, low-speed, two-stroke engine, the engine comprising a cylinder (1) with a reciprocating piston and a system, the system comprising - Lubricant supply source (25), including lubricant pump, - Multiple lubricant injectors (4) distributed along the periphery of the cylinder (1) are used to inject lubricant into the cylinder (1) at different positions on the periphery during the injection phase. - Lubricant supply conduit (9), connecting lubricant supply source (25) and lubricant injector (4). The engine also includes: - Controller (11), for controlling the amount and timing of lubricant injection from at least one lubricant injector (4), Each injector (4) includes: - An inlet port in fluid communication with the lubricant supply conduit (9) for receiving lubricant. - A nozzle (5) having a nozzle orifice (5') extending into the cylinder, configured to inject lubricant from the inlet port (4A) into the cylinder (1) during the injection phase. The method includes - To increase the lubricant pressure to the typical pressure range of the spray injector, and also includes [this feature] in cyclic operation. - During the injection phase, pressurized liquid is supplied at the inlet port of the injector and a force is applied to the valve, which drives the valve body to move within the injector (4). When the pressure rises above a predetermined limit, a predetermined volume of lubricant is pumped into the cylinder (1) through the nozzle orifice (5'). The method is characterized in that it includes the following steps: The pressure in the lubricant supply conduit (9) is varied and controlled by a controller within the desired pressure range, ranging from 10 bar to 400 bar, preferably from 25 bar to 100 bar, and optionally from 30 bar to 80 bar.

9. The method for lubricating a large, low-speed, two-stroke engine according to claim 8, characterized in that, The desired pressure depends on the engine load and the measured actual pressure in the lubricant supply conduit (9).

10. The method for lubricating a large, low-speed, two-stroke engine according to claim 8 or 9, characterized in that, The method includes the steps of: providing the engine with: - A computer (11') connected to the controller, or alternatively - The mobile phone configured to communicate with the controller.

11. The method for lubricating a large, low-speed, two-stroke engine according to any one of claims 8-10, characterized in that, The method includes the steps of: providing the engine - An adjustable valve located at the nozzle (5) is used to open and close the flow of lubricant from the pressure chamber in the injector to the nozzle orifice (5') during the injection cycle.

12. The method for lubricating a large, low-speed, two-stroke engine according to any one of claims 8-10, characterized in that, The method includes providing each injector in the form of a SIP injector.

13. The application of the engine according to any one of claims 1-6 to spray lubricant pressure in the range of 10 bar to 400 bar, preferably 25 bar to 100 bar, into the cylinder of a large marine engine or a power plant combustion engine.

14. The application according to claim 13, wherein when using the engine according to claim 7, it is characterized in that, The spray jet is a SIP spray.

15. The method according to any one of claims 8-11 is used for spraying lubricant into the cylinders of large marine engines or power plant combustion engines at a lubricant pressure of 10 bar to 400 bar, preferably 25 bar to 100 bar.

16. The application according to claim 15, wherein when using the method according to claim 12, it is characterized in that, The spray jet is a SIP spray.

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