Large slow-speed two-stroke engine, method for lubricating same, and use of such engine and method

Abstract

A method for lubricating large engines, in particular marine or power plant engines, and engines equipped with injectors, according to which one flow meter is provided for all injectors of the engine, one flow meter for all injectors of a cylinder, or one flow meter per injector of the engine, comprising the steps of measuring the lubricant flow with at least one flow meter, converting the measured actual flow to an actual quantity in a control device, comparing the calculated actual quantity with a desired value, and controlling the injectors and adjusting their settings in order to adjust the actual quantity to the desired value for the quantity of lubricant injected for a particular operating mode.

Description

[Technical field]

[0001] The present invention relates to large combustion engines, for example large slow-running two-stroke engines, to a method for lubricating such engines, and to uses thereof.

[0002] More specifically, the present invention relates to a large, slow-running, two-stroke engine having a cylinder with a reciprocating piston therein and a lubrication system, the lubrication system comprising: A lubricating oil supply unit; - a plurality of lubricant injectors distributed along the circumference of the cylinder for injecting lubricant into the cylinder at various positions along its circumference during an injection phase; a lubricant supply conduit and a lubricant return line connecting the lubricant supply with the lubricant injector; at least one flow meter for measuring the flow of the lubricant; Equipped with The engine is a control device for controlling the amount and timing of injection of lubricant by at least one of the lubricant injectors; A computer connected to the control device; Further equipped with Each injector is an inlet port fluidly connected to the lubricant supply conduit for receiving lubricant therefrom; a nozzle having a nozzle opening extending into the cylinder and configured to inject lubricant from an inlet port into the cylinder during an injection phase; an adjustable valve in the nozzle for opening and closing the flow of lubricant from a pressure chamber in the injector to the nozzle orifice during an injection cycle; Equipped with one flow meter for all injectors on the engine, one flow meter for all injectors on a cylinder, or one flow meter per injector on the engine; The controller is configured to convert the measured actual flow into an actual quantity.

[0003] The method relates to the lubrication of a large, slow-running, two-stroke engine having a cylinder with a reciprocating piston therein. [Background technology]

[0004] With an eye on environmental protection, efforts are ongoing regarding the reduction of emissions from marine engines. This also includes the steady optimization of the lubrication systems for such engines, especially due to increasing competition. One economic aspect that is receiving increasing attention is the reduction of oil consumption, not only for environmental protection reasons, but also because it is an important part of the operating costs of a ship. A further concern is to adequately lubricate despite the reduced amount of lubricant, since the engine's useful life must not be compromised by the reduced oil consumption. Thus, steady improvements in lubrication are needed.

[0005] There are several different systems for lubricating large slow-speed two-stroke marine diesel engines, including injection of the lubricating oil onto the cylinder liner or oil quill injection onto the piston rings.

[0006] An example of a lubricating oil injector for a marine engine is disclosed in EP 1 767 751, where a check valve is used to route the lubricating oil to a nozzle passage inside the cylinder liner. The check valve comprises a reciprocating spring-loaded ball in a valve seat just upstream of the nozzle passage, the ball being displaced by pressurized lubricating oil. Ball valves are a traditional engineering solution based on principles dating back to the beginning of the last century, for example as disclosed in GB 214 922 of 1923.

[0007] Compared to conventional lubrication, an alternative and relatively new lubrication method is commercially called Swirl Injection Principle (SIP). It is based on injecting a mist droplet spray of lubricating oil into the scavenging swirl inside the cylinder. The spiral upward swirl draws the lubricating oil towards the top dead centre (TDC) of the cylinder and as a result forces it outwards against the cylinder wall in a thin and uniform layer. This is described in detail in WO 2010 / 149162 and WO 2016 / 173601. The injector comprises an injector housing with a reciprocating valve member, typically a valve needle, mounted therein. The valve member, such as a needle tip, closes and opens the path of the lubricating oil to the nozzle opening according to precise timing. In current SIP systems, atomization with mist droplets is typically achieved at a pressure of 35-40 bar, which is significantly higher than the hydraulic pressure of less than 10 bar used in systems that work with a high density oil jet introduced into the cylinder. Also, in some types of SIP injectors, the high pressure of the lubricant is used to move a spring-biased valve member against a spring force away from a nozzle orifice, from which the highly pressurized oil is expelled as a mist of droplets. The expulsion of oil results in a drop in oil pressure against the valve member, causing the valve member to return to its origin where it remains until the next lubrication cycle, when high pressure lubricant is again supplied to the lubricant injector.

[0008] In such large marine engines, a number of injectors are arranged around the cylinder, each with one or more nozzle openings for delivering a jet or spray of lubricating oil from each injector into the cylinder. Examples of SIP lubricating oil injector systems for marine engines are disclosed in WO 2002 / 35068, WO 2004 / 038189, WO 2005 / 124112, WO 2010 / 149162, WO 2012 / 126480, WO 2012 / 126473, WO 2014 / 048438 and WO 2016 / 173601.

[0009] For SIP injection, in addition to the goal of minimizing oil consumption, precisely controlled timing is essential. For this reason, SIP systems are specially designed for a fast reactive response during the injection cycle.

[0010] WO 2011 / 110181 describes the importance of accurate lubricant dosing in marine engine lubrication systems. For accurate timing of dosing, a double valve system is disclosed that separately controls the opening and closing times of the lubricant injector, allowing the system to be tailored to short dosing times. However, accurate adjustment of the dosing time is not sufficient for accurate dosing, since the dosing amount is not only determined by the length of the dosing time, but also depends on the pressure and viscosity of the lubricant, which in turn depends on the temperature.

[0011] WO 02 / 35068 discloses an injector including a pump system, in which during the injection phase a reciprocating plunger member moves forward towards the nozzle, thereby causing a pressure rise in a predetermined amount of lubricant inside the injector, so that this predetermined amount of lubricant is pumped through the nozzle opening. The pump system is operated by high pressure oil supplied to the injectors by a control device, which centrally supplies high pressure oil to all the injectors. Each injector has a controllable motor-driven actuator for adjusting the stroke length of the reciprocating plunger. Such a system is simple in that the injection is centrally regulated by the high pressure oil delivery from the control device, the regulation operation being the same for all injectors in terms of injection timing and frequency. However, such an injector is relatively complex and expensive, in that each injector is provided with a motorized injection amount regulation adjustment system. Also, the fact of providing a motor for each injector increases the risk of failure, not only due to the motor itself, but also due to the risk of thermal and mechanical damage to the necessary electrical cabling. It would be desirable to provide a more robust and precise system.

[0012] While the introduction of HJL's Smartlube 4.0 system has improved the performance of lubrication systems, there is a need for an engine and method that automatically ensures that the system delivers the desired amount of lubricant regardless of disturbances such as lubricant type, pressure and temperature changes, and mechanical wear of components within the lubrication system.

[0013] Additionally, in the situation where one injector is taken out of service, it is desirable for the remaining injectors to automatically adjust their delivery of lubricant.

[0014] The principles provided in the prior art are not optimal, especially when high pressure and fast response are required, such as SIP injection, in part because the oil supply lines are relatively long and can undergo minute expansions and contractions when pressure is applied to the tubes and released, which introduces uncertainty in timing and injection volume.

[0015] It would therefore be desirable to provide a system that automatically provides a more accurate delivery of a desired amount of lubricant.

[0016] The engine and method described in the preamble and defined in the preamble of the independent engine and method claim are known from the above-mentioned WO 2021 / 126473.

[0017] This document does not disclose a controller or database that stores multiple desired values ​​for the amount of lubricant injected for a particular mode of operation. This document does not teach a controller configured to calibrate the injector by mapping the amount of lubricant injected at different injection phases, nor does it teach that the results can be used to determine the injection phase of the injector to obtain a desired amount of lubricant during injection. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] European Patent No. 1767751 [Patent Document 2] British Patent No. 214922 [Patent Document 3] International Publication No. 2010 / 149162 [Patent Document 4] International Publication No. 2016 / 173601 [Patent Document 5] WO 2002 / 35068 [Patent Document 6] International Publication No. 2004 / 038189 [Patent Document 7] International Publication No. 2005 / 124112 [Patent Document 8] International Publication No. 2010 / 149162 [Patent Document 9] International Publication No. 2012 / 126480 [Patent Document 10] International Publication No. 2012 / 126473 [Patent Document 11] International Publication No. 2014 / 048438 [Patent Document 12] International Publication No. 2016 / 173601 [Patent Document 13] International Publication No. 2011 / 110181 [Patent Document 14] International Publication No. 2021 / 126473 [Patent Document 15] International Publication No. 2019 / 114905 [Non-patent literature]

[0019] [Non-Patent Document 1] Rathesan Raveendran et al., "Rheological Behavior of Lubricating Oils Used in Two-Stroke Marine Engines," Industrial Lubrication and Tribology, Vol. 69, No. 5, 2017, pp. 750-753 Summary of the Invention [Problem to be solved by the invention]

[0020] SUMMARY OF THE PRESENT EMBODIMENT It is an object of the present invention to improve upon the prior art systems to achieve the desired effect in the form of automatically providing a more precise delivery of a desired amount of lubricant.

[0021] In particular, the aim is to improve the lubrication with SIP injectors or with a common rail system with conventional check valves in large combustion engines, for example large slow-running two-stroke engines. However, the method according to the invention can also be used in large four-stroke combustion engines, for example marine engines or power plant combustion engines. These aims are achieved by a large combustion engine, for example a slow-running two-stroke engine, with multiple injectors, a method for lubricating such an engine, and its uses, as will be made clear below. [Means for solving the problem]

[0022] The invention may be used in any lubrication principle in which the injectors receive pressurized lubricant from the lubrication system via one lubricant supply conduit per injector.

[0023] The invention can also be used with lubrication principles in which multiple lubricant supply conduits are replaced by a single common supply line, in which case the pipe connections supply lubricant to the injectors by a "common rail" system, where all the injectors of an engine cylinder, or a subgroup of injectors for a single engine cylinder, receive lubricant in common and simultaneously via a single lubricant supply line.

[0024] Optionally, a return line is provided for backflow of lubricant from the injector.

[0025] The engine is unique in that it: the engine further comprises a plurality of desired values ​​for the amount of lubricant injected, typically defined as a delivery rate, for a particular operating mode, the desired values ​​being stored in a database within the control device; the control device being configured to compare the calculated actual amount with a desired value and to control the injector to adjust its settings in order to obtain a desired value for the amount of lubricant injected for a particular operating mode; and the control device is configured to calibrate the injector by measuring the amount of lubricant injected at different injection phases, mapping the results, and using the results to determine the injection phase of the injector to obtain a desired amount of lubricant during injection; It is.

[0026] The method according to the present invention is a method for lubricating a large, slow-running, two-stroke engine having a cylinder with a reciprocating piston therein and a system comprising: A lubricating oil supply unit; a plurality of lubricant injectors distributed along the circumference of the cylinder for injecting lubricant into the cylinder during an injection phase at various positions along the circumference of the cylinder; a lubricant supply conduit and a lubricant return line connecting the lubricant supply with the lubricant injector; at least one flow meter for measuring the flow of the lubricant; Equipped with The engine is a control device for controlling the amount and timing of injection of lubricant by at least one of the lubricant injectors; A computer connected to the control device; Further equipped Each lubricator is an inlet port fluidly connected to the lubricant supply conduit for receiving lubricant therefrom; a nozzle having a nozzle opening extending into the cylinder and configured to inject lubricant from an inlet port into the cylinder during an injection phase; an adjustable valve in the nozzle for opening and closing the flow of lubricant from a pressure chamber in the injector to the nozzle orifice during an injection cycle; Equipped with The method includes, in a cyclic operation, during an injection phase, supplying pressurized liquid to an inlet port of the injector, exerting a force on an adjustable valve, which force moves a valve body within the injector, and pumping a predetermined amount of lubricant through a nozzle opening into the cylinder when the pressure rises above a predetermined upper limit; - after the injection phase, retracting the valve body by expelling pressurized liquid from the injector; During the retraction, refilling a pressure chamber in the injector with lubricant for a next injection phase; providing one flow meter for all injectors of an engine, one flow meter for all injectors of a cylinder, or one flow meter per injector of an engine; measuring lubricant flow with at least one flow meter; converting the measured actual flow into an actual quantity within the control device; Including, The method comprises: providing the engine with a number of desired values ​​for the amount of lubricant injected, typically defined as a delivery rate, for a particular mode of operation, which desired values ​​are stored in a database within the controller; comparing the calculated actual amount to a desired value; controlling the injector to adjust its settings to adjust the actual amount of lubricant injected to the desired value for a particular operating mode; performing continuous adjustments of the lubricant quantity at different time intervals varying between 10 milliseconds and 10 minutes, the continuous adjustments including adjustments of the lubricant quantity at different sample intervals varying from one adjustment per injection to adjustments based on 100 previous injections; or performing discontinuous adjustments of the lubricant amount at time intervals between 1 minute and 30 days, preferably between 1 hour and 30 days, more preferably between 1 day and 30 days, the discontinuous adjustments including calibration of the injector, the calibration being performed by measuring the amount of lubricant injected at different injection phases, mapping the results and using the results to determine the injection phase of the injector in order to obtain a desired amount of lubricant at injection; Includes.

[0027] In order to fully appreciate the present invention, it is pointed out that it has been found that the substantial length of the lubricant conduit from the pump system to the cylinder with the multiple injectors introduces inaccuracies into the system. The long conduits tend to expand and contract slightly when exposed to high pressures of the lubricant, introducing small uncertainties in the timing and amount of lubricant injected. Furthermore, the lubricant undergoes minute compression and expansion during the injection cycle, which increases its effect. Although this effect is small, it introduces errors in the injection in the range of several milliseconds, which is significant compared to the short injection times, which may be as short as only 10 milliseconds or less. Such inaccurate timing effects have a significant impact on the lubricant system due to the high pressure of the lubricant and the short injection times. It is also noted that the injection amount is usually regulated by the length of time that pressurized oil is delivered to the nozzle in the injection cycle, in which case the uncertainties affecting the exact timing must be minimized, if not eliminated. Improvements in injection are achieved with the injector described herein because the selection valve system is internal to the injector, shortening the distance from the selection valve system to the nozzle.

[0028] In the present invention, the control of the amount of lubricant injected is carried out based on the measured actual flow and on a calculation of the amount of lubricant injected, based on which the control device allows the setting of the injector if the actual amount of lubricant differs from the desired amount, thereby eliminating the risk that a change in the operating parameters would result in an incorrect amount of lubricant being injected.

[0029] The control device controls the adjustable valve to adjust the stroke length of a valve member in the form of a plunger, whereby the amount of lubricant is variably adjustable during the injection phase by means of a stroke length adjustment mechanism. Adjustment is achieved when the plunger is not fully retracted to its maximum retractable position. Since the stroke of the plunger is always in the same position, e.g. the same most forward position, the stroke length is adjusted by varying the retracted position of the plunger after retraction.

[0030] The controller may be built into the injector or may be connected by wires or wirelessly to the injector and flow meter.

[0031] The controller may also be configured to control the type of lubricant used.

[0032] The engine is unique in that the controller is configured to calibrate the injector by measuring the amount of lubricant injected at different injection phases, mapping the results, and using the results to determine the injection phase of the injector to obtain a desired amount of lubricant during injection.

[0033] This allows the injectors to be calibrated. The calibration can be performed while the engine is running. Alternatively, the calibration can be performed while the engine is shut down. More accurate injection is obtained since the deviation between the injectors is reduced.

[0034] In one embodiment, there may be a flow meter for every injector on the engine, in another embodiment there may be one flow meter for every injector on a cylinder, and in yet another embodiment there may be one flow meter per injector on the engine.

[0035] In some embodiments, the maximum retractable position of the plunger is the rearmost possible position at the maximum distance from the nozzle opening, but it is also possible to hold the plunger at a predetermined distance from the rearmost possible position. By adjusting that distance, the stroke length is reduced relative to the maximum retractable position, and so the injection volume of the next injection is adjusted. The effect is similar to the screw-adjustable end stop of WO 02 / 35068, but the stroke length adjustment mechanism can be provided centrally and remotely from the syringe, in contrast to the syringe of WO 02 / 35068.

[0036] The method and engine according to the present invention automatically provides precise delivery of the desired amount of lubricant by adjusting the adjustable valve.

[0037] The principle of the present invention allows automatic and continuous adjustment of the amount of lubricant injected, and also provides for calibration of the injectors, thereby significantly reducing deviations in the amount injected by each injector.

[0038] The engine according to the invention may be equipped with a hydraulically operated inlet valve system, each injector having: an inlet port fluidly connected to the lubricant supply conduit for receiving lubricant therefrom; a nozzle having a nozzle opening extending into the cylinder and configured to inject lubricant from an inlet port into the cylinder during an injection phase; an outlet valve system at the nozzle for opening and closing the flow of lubricant to the nozzle orifice during an injection cycle; a prechamber within the injector between the lubricant inlet port and the outlet valve system for receiving and storing a quantity of lubricant from the inlet port prior to an injection phase; Equipped with the outlet valve system is configured to open to allow the lubricant to flow from the front chamber through the outlet valve system to the nozzle opening as soon as pressure rises above a predetermined upper pressure limit in the front chamber and in the outlet valve system during the injection phase, and to close the outlet valve system after the injection phase; Each injector further comprises: a pressure control port fluidly connected to the pressure control conduit for receiving pressurized liquid therefrom during an injection phase; a pressure chamber in communication with the pressure control port for cyclically receiving pressurized liquid from the pressure control port during the injection phase and discharging it therefrom after the injection phase; a reciprocating hydraulically actuated actuator-plunger in contact with the pressure chamber and prestressed by a spring load from an actuator-plunger spring, the actuator-plunger being configured for actuation driven by pressurized liquid in the pressure chamber during an injection phase, the actuation of the actuator-plunger being configured to provide a pressure rise in the lubricant in the antechamber above a predetermined upper pressure limit; Equipped with The engine further comprises a stroke length adjustment mechanism for variably adjusting the stroke length of the reciprocating hydraulically driven actuator-plunger, in such an embodiment, the stroke length adjustment mechanism is configured to variably adjust the amount of pressurized liquid expelled from the pressure chamber during the injection phase.

[0039] The effect of the variable adjustability is similar to the screw adjustable end stop of WO 02 / 35068, however the stroke length adjustment mechanism can be centrally located remote from the syringe, in contrast to the syringe of WO 02 / 35068.

[0040] In some practical embodiments, the stroke length adjustment mechanism comprises a pressure regulator for variably adjusting the idle pressure in the pressure chamber during the injection phase, the idle pressure being lower than a predetermined upper limit in order to only partially counteract the spring load from the actuator-plunger spring on the actuator-plunger, thereby variably adjusting the retracted position of the actuator-plunger.

[0041] The outlet valve system blocks back pressure from the cylinder and prevents lubricant from entering the cylinder unless the outlet valve is open. In addition, the outlet valve system facilitates a short closing time after injection, enhancing accuracy in the timing and amount of lubricant injected.

[0042] An engine with a hydraulically actuated inlet valve system can be operated according to a method including a stroke length adjustment mechanism configured to variably adjust the amount of pressurized liquid discharged from the pressure chamber (27) during an injection phase, the method including adjusting the stroke length during an injection cycle by adjusting the amount of pressurized liquid discharged from the pressure chamber (27) after the injection phase.

[0043] The engine and method comprises a hydraulically actuated inlet valve system as known from WO 2019 / 114905. However, the engine differs in that it comprises a flow meter 35. The flow meter is intended to be used to measure the flow of lubricant in the lubricant supply conduit 9.

[0044] The engine according to the invention may also include a hydraulically actuated inlet valve system, each injector being a lubricant inlet port for receiving lubricant from a lubricant feed conduit; a nozzle having a nozzle opening extending into the cylinder and configured to inject lubricating oil into the cylinder through an inlet port; an outlet valve system at the nozzle for opening and closing the flow of lubricant to the nozzle orifice during an injection cycle; Equipped with The outlet valve system is configured to open for flow of lubricant to the nozzle opening as soon as pressure rises above a predefined upper pressure limit in the outlet valve system during the injection phase, and to close the outlet valve system after the injection phase. In such an embodiment, each injector may comprise an electrically actuated inlet valve system electrically connected to the controller and disposed between the lubricant inlet port and the nozzle, and regulating the lubricant dispensed through the nozzle opening by opening or closing the flow of lubricant from the lubricant inlet port to the nozzle in response to an electrical control signal received from the controller, the inlet valve system being disposed upstream of and remote from the nozzle, and upstream of and remote from the outlet valve system.

[0045] According to a particular embodiment of this type, the inlet valve system may comprise an inlet check valve having an inlet valve member prestressed towards an inlet valve seat by an inlet valve spring and arranged to pass lubricant from the lubricant inlet to the outlet valve system upon displacement of the inlet valve member from the inlet valve seat against a force from the inlet valve spring, the inlet valve system further comprising an electrically actuated rigid displacement member for displacing the inlet valve member from the inlet valve seat during lubricant injection.

[0046] To provide better control over the rate and amount of lubricant discharged by the injectors, each of the injectors includes an electrically actuated inlet valve system disposed between the lubricant inlet port and the nozzle, electrically connected to the controller, and for regulating lubricant dispensed through the nozzle opening by opening or closing the flow of lubricant from the lubricant inlet port to the nozzle in response to electrical control signals received from the controller, the inlet valve system being disposed upstream of and remote from the nozzle, and upstream of and remote from the outlet valve system.

[0047] The injector inlet valve system introduces a quantity of lubricant for injection by a time that the inlet valve system remains open for an injection phase, the time being determined by the controller.

[0048] An engine with an electrically operated inlet valve system may be operated according to a method including sending an electrical control signal from a controller to the electrically operated inlet valve system to initiate an injection phase, thereby causing a flow of lubricant from a lubricant feed conduit through a lubricant inlet port, through the inlet valve system and into a conduit fluidly connecting the inlet valve system with an outlet valve system, increasing pressure in the conduit due to the flow of lubricant into the conduit, causing the increased pressure to open the outlet valve system to allow lubricant to flow from the conduit to a nozzle opening, injecting lubricant into the cylinder through the nozzle opening, and at the end of the injection phase, modifying the electrical control signal from the controller to the inlet valve system, and closing the inlet valve system for supply of lubricant from the lubricant inlet port to the conduit.

[0049] The engine and method comprise an electrically actuated inlet valve system as known from WO 2019 / 114905. However, the engine differs in that it comprises a flow meter, which is intended to be used to measure the flow of lubricating oil in the lubricating oil feed conduit.

[0050] According to a further embodiment, the engine is unique in that the lubrication system is selected from a mechanically driven system, a hydrostatically driven system, and a common rail system.

[0051] The principles of the present invention are versatile and can be used in a variety of lubrication systems.

[0052] According to a further embodiment, the engine is unique in that a flow meter is provided in the lubricant supply conduit connected to the injector.

[0053] This measures the actual flow into the injector. The flow meter can be located just before the inlet port of a single injector, or alternatively, in a common supply conduit for multiple injectors, for example multiple injectors on a single cylinder.

[0054] According to a further embodiment, the engine is unique in that the flow meters are integrated into the injectors, with one flow meter located per injector on the engine.

[0055] This results in a compact system

[0056] According to a further embodiment, the engine is unique in that the controller is configured to calibrate the injector by measuring the amount of lubricant injected at different injection phases, mapping the results, and using the results to determine the injection phase of the injector to obtain a desired amount of lubricant during injection.

[0057] This allows the injectors to be calibrated. The calibration can be performed while the engine is running. Alternatively, the calibration can be performed while the engine is shut down. More accurate injection is obtained since deviations between the injectors are reduced.

[0058] Principles according to the invention allow adjustments to be performed either at time intervals based on the number of injections or at sample intervals. The term "continuously" means that the adjustments are performed as a series of adjustments at a given frequency, without pauses between adjustments. Instead, adjustments are performed at user-determined intervals.

[0059] If the method includes adjusting the amount of lubricant discontinuously over time intervals, the time intervals can be short, with a lower limit of as little as one minute, so that the adjustment is performed as a more or less continuous adjustment. In some embodiments, the method includes discontinuous adjustments including calibration of the injector, which is performed by measuring the amount of lubricant injected at different injection phases, mapping the results and using the results to determine the injection phase of the injector in order to obtain the desired amount of lubricant during injection.

[0060] The injector can be calibrated at user determined time intervals, and as mentioned above, the calibration can be performed while the engine is running.

[0061] In some embodiments, the method includes a calibration of the injector performed with respect to an operating spectrum of the injector, the operating spectrum being typically between 0 and 100 ms.

[0062] In some embodiments, the method includes implementing an automatic inspection program to control the injectors of the cylinders to deliver a desired and sufficient amount of lubricant.

[0063] If the test indicates a requirement for sufficient lubrication oil volume, then a calibration can be performed automatically under the control of the controller or alternatively, a calibration can be performed manually.

[0064] In some embodiments, the method includes that in situations where an incorrect amount of lubricant is dispensed, particularly when the amount of lubricant is insufficient, a calibration of the injector is performed manually or automatically.

[0065] In some embodiments, the method includes the inspection program involving correcting the calibration.

[0066] The test program may include routines that modify the calibration parameters.

[0067] In some embodiments, the method includes that the adjustment of the amount of lubricant is controlled by feedback control / adjustment, such as PID adjustment or more advanced model-based adjustment.

[0068] In some embodiments, the method includes storing the adjustment values ​​in a database within the controller.

[0069] In some embodiments, the method includes storing calibrated timing values ​​for each injector in a database within the controller.

[0070] The method and engine according to the invention are particularly suitable for use in ring pack lubrication or in-cylinder SIP injection of large marine engines or power plant combustion engines at lubricant pressures in the range of 25 bar to 100 bar. The method is also suitable for combined SIP and ring pack lubrication.

[0071] definition The term "adjusting" refers to the situation where the amount of lubricant is changed during engine operation to correspond to a desired amount.

[0072] The term "adjust" refers to the situation where the amount of lubricant is changed when calibrating the injector.

[0073] The term "injector" is used for an injection valve system that comprises a housing with a lubricant inlet and one or more injection nozzles with nozzle openings as lubricant outlets, and opens and closes the path of lubricant to the nozzle openings. The injector has a single nozzle that extends through the cylinder wall into the cylinder, although the nozzle itself optionally has multiple openings if the injector is appropriately mounted. For example, a nozzle with multiple openings is disclosed in WO2012 / 126480.

[0074] The term "injection phase" is used in reference to the time during which the lubricant is injected into the cylinder by the injector.

[0075] The term "idle phase" is used in reference to the time between injection phases.

[0076] The term "idle state" is used in reference to the state of a component in an idle phase.

[0077] The term "idle phase position or orientation" is used in reference to the position or orientation of a moving component when it is idle during an idle phase, as opposed to an injection phase position.

[0078] The term "injection cycle" is used with respect to the time taken from the start of an injection sequence until the next injection sequence begins. For example, an injection sequence may consist of a single injection, in which case the injection cycle is measured from the start of the injection phase to the start of the next injection phase. Alternatively, the injection sequence may consist of multiple injections, for example multiple injections above the piston before the piston passes the injector on its way to TDC, for example a first injection with one lubricant followed by another injection of another lubricant, possibly further lubricants and / or additives. Such double or multiple injections mix the oil in the cylinder before the piston reaches TDC. For example, there is one injection cycle per revolution of the engine. However, it is also possible to have one injection cycle after multiple engine revolutions.

[0079] The term "timing" of an injection is used in reference to adjusting the start of the injection phase by the injector relative to a particular position of the piston inside the cylinder.

[0080] The term "frequency" of an injection is used in reference to the number of repeated injections by an injector per revolution of the engine. If the frequency is 1, there is one injection per revolution. If the frequency is 1 / 2, there is one injection per two revolutions. This terminology is consistent with the prior art discussed above.

[0081] The term "pressurized lubricant" is used in reference to lubricant supplied at a pressure high enough that it can be injected as a jet or spray into the cylinder. This is in contrast to oil injection by a quill between the piston rings. The pressure depends on the purpose and form of injection, but is usually greater than 10 bar. For SIP injection, the pressure is generally much higher, for example greater than 25 bar.

[0082] The term "flow meter" is used in reference to a component that can measure flow regardless of the method used, such as pressure differential, viscosity, temperature, volume, etc.

[0083] Practical embodiment A large engine, for example a slow-speed two-stroke engine, optionally a marine engine or a power plant engine, comprises a cylinder with a reciprocating piston therein and a number of lubricant injectors fixed to and extending through the cylinder wall. The injectors are distributed along the circumference of the cylinder and are configured to inject lubricant into the cylinder at various positions along the circumference during an injection phase. A large engine, for example a slow-speed two-stroke engine, is a marine engine or a power plant engine. Typically, the engine burns diesel or gaseous fuel.

[0084] The engine also typically includes a lubricant supply having pressurized lubricant oil provided by a lubricant supply pump. Optionally, the engine includes two or more lubricant supplies, correspondingly two or more types of lubricant oil, and correspondingly two or more lubricant supply pumps.

[0085] Each of the multiple injectors is connected with a respective lubricant inlet to the lubricant supply via a corresponding feed conduit. Each lubricant supply includes a potential pressure source, typically a lubricant pump, which increases the pressure of the corresponding lubricant to an appropriate level. For the described system, it is sufficient to provide a constant lubricant pressure at the lubricant inlet of the injector.

[0086] The injector is configured for the type of lubricant to be injected. The inlets can be used to supply and add not only the lubricant but also potential additives. For example, the injector optionally has multiple inlets, one for a lubricant, such as lubricating oil, and one for additives.

[0087] The engine further comprises a control device, which is adapted to control the amount and timing of injection of lubricant by the injector. Optionally, the injection frequency is also controlled by the control device. For accurate injection, it is advantageous if the control device is electronically connected to or comprises a computer, which monitors parameters related to the actual state and operation of the engine. Such parameters serve to control an optimized injection. Optionally, the control device is provided as an add-on system for upgrading existing engines. A further advantageous option is the connection of the control device to a human machine interface (HMI), which comprises a display for monitoring and an input panel for adjusting and / or programming the injection profile and optionally the parameters related to the engine state. The electronic data connection is optionally wired or wireless, or a combination thereof.

[0088] In a specific embodiment, the injector comprises a lubricant inlet for receiving lubricant from a lubricant feed conduit and injecting it into the cylinder. The lubricant inlet of the injector is connected to a lubricant supply via the feed conduit.

[0089] The injector has a lubricant flow path from the lubricant inlet to at least one nozzle for flow of lubricant from the lubricant inlet through the at least one nozzle and into the cylinder.

[0090] The injector comprises one or more nozzles, for example two nozzles, each having a nozzle opening and extending into the cylinder for injecting the lubricant during the injection phase. Optionally, the nozzle comprises two or more openings. For example, nozzles with multiple openings are disclosed in WO2012 / 126480. In some embodiments, the injector comprises a single nozzle with a single nozzle opening.

[0091] In particular, each injector includes an internal actuator-driven valve system in the lubricant flow path configured to selectively switch from an idle state without lubricant injection to an injection state injecting lubricant into the cylinder through at least one nozzle during an injection phase in response to a received injection phase signal.

[0092] Each injector includes an actuator for actuating a valve system, the actuator being operatively connected to the controller and configured to be actuated by the controller to selectively actuate the valve system to provide injection of lubricant as a result of actuator actuation under control of the controller, the valve system being used to select the amount and timing to be used for injection, as well as the injection sequence, under control of the controller.

[0093] During operation, the actuator is actuated by the controller to initiate a lubricant injection phase, which results in the valve system being caused to open, allowing lubricant to flow through the passageway and into the cylinder, and at the end of the injection phase, the actuator is caused to close the valve system to stop the supply of lubricant.

[0094] Example of pressure control In certain embodiments, the engine includes a lubricant feed conduit containing lubricant at a first pressure and a pressure control conduit containing pressurized liquid at a pressure higher than the first pressure. In such a case, the injector includes an internal hydraulically driven pump system, where pressurized liquid is used to drive the pump system inside the injector housing, which pressurizes the lubricant within the injector and releases it therefrom. The injector includes a lubricant inlet port fluidly connected to the lubricant feed conduit to receive lubricant therefrom for injection into the cylinder. The injector also includes a pressure control port fluidly connected to the pressure control conduit to receive pressurized liquid therefrom during an injection phase.

[0095] The injector comprises an antechamber inside the injector between the lubricant inlet port and the outlet valve system for receiving and storing a quantity of lubricant from the inlet port prior to an injection phase.

[0096] A pressure chamber in the injector communicates with a pressure control port to receive pressurized liquid therefrom during an injection phase, the pressurized liquid in the pressure chamber driving a pump system in the injector, the pump system comprising a reciprocating hydraulically driven actuator-plunger in contact with the pressure chamber and prestressed by a spring load from an actuator-plunger spring, the reciprocating hydraulically driven actuator-plunger being configured to be driven by the pressurized liquid in the pressure chamber during the injection phase, e.g. towards a nozzle, thereby causing a pressure rise in the lubricant in the anterior chamber above a predetermined upper limit and pumping this predetermined amount of lubricant into the cylinder via a check valve and a nozzle opening.

[0097] injection Optionally, the injection phase consists of multiple injections, for example multiple injections above the piston before the piston passes the injector on its way to TDC, for example a first injection with lubricant followed by another injection of another lubricant, possibly further lubricants and / or additives. Such double or multiple injections allow mixing of the oil in the cylinder before the piston reaches TDC, especially in case of SIP operation. Various selections of the lubricants to be injected, their amounts and timings, controlled by the control device, allow various injection sequences, for example a combination of at least two of the following: - one or more injections under the piston, - one or more injections on the piston, - One or more injections above the piston during a single injection cycle.

[0098] For various injections, the choice of lubricant(s) may also vary, possibly including additives.

[0099] For example, the actuators are electrically controlled actuators and are electrically connected to the controller with electrical connections for receiving an injection phase signal from the controller indicating the timing of injection. With respect to the injection phase, an electrical control signal is sent from the controller to each injector to initiate the injection phase of the lubricant. As a result, the valve system opens and allows the lubricant to flow through the flow passage and inject into the cylinder. At the end of the injection phase, the electrical control signal from the controller to the injectors is changed to close the valve system to inject the lubricant and return to an idle state.

[0100] Optionally, the actuator comprises an electric solenoid arrangement having a stationary solenoid portion and a movable solenoid portion, the valve system being coupled to the movable solenoid portion that is driven by the actuator upon electrical excitation of the solenoid, the solenoid being configured to be energized by an injection phase signal from the controller.

[0101] The term "solenoid coil" should be understood as "at least one solenoid coil", since it is possible and in some cases advantageous to use more than one coil, for example two or three coils.

[0102] The term "signal" from the controller is used herein in reference to a current flowing from the controller to the injector. In some embodiments, the signal itself can be used to drive an actuator, for example an electromechanical actuator, if the current is strong enough. For example, to switch the drive direction of an electromechanical actuator, the direction of the current is switched to the opposite direction. However, the injector can alternatively comprise an electrical switch that opens to allow the signal from the controller to pass a current strong enough to drive the actuator. In the latter case, the signal line from the controller to the electrical switch can be realized with very thin wires. Alternatively, the term "signal" is also used for a wireless signal.

[0103] Alternatively, the actuator is a hydraulic or pneumatic actuator. Such hydraulic or pneumatic actuators in the injector are optionally also electrically controlled. For example, an electrical signal from the controller to the injector opens an electromechanical actuator valve in the injector, causing hydraulic or pneumatic flow into the actuator, which in turn hydraulically or pneumatically drives the valve system. Optionally, an electrical signal from the controller to the injector opens an electromechanical actuator valve, causing hydraulic or pneumatic flow into the actuator, which itself drives the valve system, which in turn drives the valve system, via a mechanical linkage.

[0104] In some embodiments, the valve system is configured to select only one injector at a time from among the multiple injectors for supplying and injecting the lubricant. In some embodiments, alternatively or additionally, the valve system is configured to select more than one injector at a time from among the multiple injectors for supplying and injecting the lubricant to simultaneously inject multiple lubricants or lubricants combined with additives.

[0105] In some embodiments, the injector has two or more nozzles and multiple lubricants and additives can be injected into the cylinder through separate nozzles of the injector, while in other embodiments, multiple lubricants and additives are injected into the cylinder through a single nozzle and optionally mixed within the injector before being released from the nozzle opening.

[0106] In a practical embodiment, the injector comprises a base and a rigid, optionally cylindrical, flow chamber that rigidly couples the base with the nozzle in order to fix the nozzle inside the cylinder wall when the base is fixed to the cylinder wall. The base is provided at the opposite end of the flow chamber to the nozzle, and is therefore usually located on the outer surface or outside of the cylinder wall. For example, the injector comprises a flange on the base for mounting on the outer cylinder wall. Alternatively, the injector comprises a flange provided around the flow chamber in order to mount the injector to the cylinder wall. For example, the flange is bolted to the cylinder wall.

[0107] Advantageously, the base comprises the first and second inlets and optionally further inlets. The flow chamber is hollow and includes a flow passage for oil to flow from the oil inlet through the flow chamber to the nozzle for injecting the oil into the cylinder. Optionally, a valve member is disposed within the flow chamber or the base.

[0108] For example, if the injector is mounted to the cylinder wall, the actuator may be provided outside the cylinder wall. Optionally, the actuator is fixed to the base.

[0109] In practice, the injection phase signal is received by an actuator which causes the actuator to move a valve member to an injection phase position or orientation in response to the injection phase signal, thereby opening a flow passage for injecting lubricant into the cylinder.

[0110] For example, the actuator is mechanically coupled to a selected valve member by an actuator extension for driving the valve member with the actuator extension. This is advantageous when the valve member is located within the flow chamber and thus inside the cylinder wall, while the actuator is located outside the cylinder wall. In this embodiment, the operation includes moving the valve member with the actuator using the actuator extension.

[0111] Outlet Valve System Optionally, each injector comprises an outlet valve system at the nozzle, configured to open to allow lubricant to flow to the nozzle opening as soon as the pressure rises above a predefined upper limit during the injection phase, and to close the outlet valve system when the pressure drops after the injection phase. The outlet valve system blocks back pressure from the cylinder and prevents lubricant from entering the cylinder during the idle phase between the injection phases. In addition, the outlet valve system facilitates a short closing time after injection, enhancing the accuracy of the timing and amount of lubricant injected.

[0112] In these embodiments, the injector includes a lubricant flow path from the lubricant inlet through the valve system and the outlet valve system to the outlet valve system for lubricant to flow from the lubricant inlet through the valve system and the outlet valve system and out of the injector at a nozzle opening. The valve system is located upstream of the nozzle as part of the injector and optionally spaced apart from the nozzle. Optionally, the valve system is located upstream of the outlet valve system and spaced apart from the outlet valve system.

[0113] For example, the outlet valve system comprises an outlet check valve. In the outlet check valve, an outlet valve member, for example a ball, an ellipsoid, a plate or a cylinder, is preloaded by an outlet valve spring towards an outlet valve seat. As soon as pressurized lubricant is supplied into the flow chamber upstream of the outlet valve system, the force of the preloading spring is countered by the lubricant pressure, and if the pressure becomes higher than the spring force, the outlet valve member is displaced from its outlet valve seat and the check outlet valve opens to inject lubricant into the cylinder through the nozzle opening. For example, the outlet valve spring acts on the valve member in a direction away from the nozzle opening, although a reverse movement is also possible.

[0114] For example, to lubricate an engine, the method includes sending an electrical control signal from the controller to an injector and causing the injector to open the inlet valve system to allow lubricant to flow from a lubricant supply conduit, through a lubricant inlet, through the valve system, and into a conduit fluidly connecting the inlet valve system with the outlet valve system.

[0115] It should be noted that during the injection phase, in order for the lubricant supply conduit to supply the lubricant through the inlet valve system at a pressure high enough to open the outlet valve system, the pressure of the lubricant in the lubricant supply conduit exceeds a predetermined upper limit that determines the opening of the outlet valve system. Thus, when the lubricant flows through the inlet valve system into the conduit between the inlet valve system and the outlet valve system, the pressure rises in the outlet valve system, which opens the outlet valve system to allow the lubricant to flow from the conduit to the nozzle opening, whereby the lubricant is injected into the cylinder through the nozzle opening. At the end of the lubrication time, the electrical control signal from the control device is changed so that the inlet valve system for supplying the lubricant from the lubricant inlet to the nozzle opening is closed again. The pressure in the conduit drops again and the outlet valve system is closed.

[0116] In these embodiments, there are at least two valve systems within the injector. The inlet valve system is regulated under the control of a controller, for example by an electrical signal from the controller, and once the inlet valve system is open to allow high pressure lubricant flow from the lubricant feed conduit to the outlet valve system, the outlet valve system is actuated only by the high pressure of the lubricant in the outlet valve system. There is no mechanical coupling linking the moving parts of the inlet valve system with the moving parts of the outlet valve system. The coupling between the opening and closing of these two systems is only provided by the lubricant flowing from the inlet valve system to the outlet valve system.

[0117] Valve and actuator options in detail In some practical embodiments, the valve system comprises a movable actuator-driven valve member arranged to move from an idle phase position in which the valve member blocks the flow passage during an idle phase to an injection phase position in which the valve member opens the flow passage and allows lubricant to flow through it during an injection phase. Advantageously, the valve member is prestressed towards the idle phase position by a valve spring.

[0118] In some embodiments, to actuate the movable valve member, the injector comprises a movable, actuator-driven rigid actuator extension which couples the actuator to the valve system and is used by the actuator to displace or rotate the valve member from an idle phase position in which the valve member blocks the flow path to an injection phase position in which the valve member opens the flow path to allow flow of lubricant through the flow path for injecting lubricant into the cylinder during the injection phase.

[0119] Optionally, the actuator driven rigid actuator extension is a pull / push member that selectively pulls or pushes the valve member during injection. Alternatively, the actuator extension is a rotating member that transmits driving force from the rotary actuator, e.g., selectively in one direction or the other.

[0120] In some embodiments, the actuator is an electrically controlled actuator, e.g., an electromechanical actuator. Optionally, the actuator comprises an electric solenoid arrangement having a stationary solenoid portion and a movable solenoid portion, the actuator extension portion being coupled to the movable solenoid portion to be driven by electrical excitation of the solenoid, the solenoid being configured to be excited by an injection phase signal from a controller.

[0121] For example, the valve system may include a linear actuator for driving an actuator extension, where the actuator extension is coupled to an actuator, e.g., a solenoid plunger and solenoid coil arrangement, such that upon electrical actuation of the actuator, the actuator extension, e.g., a pull-push member, is driven to open, resulting in flow from the lubricant inlet. Optionally, the actuator extension is coupled to the solenoid plunger, while the solenoid coil is stationary within the injector. Alternatively, the actuator extension is coupled to a solenoid coil that is movable with the actuator extension.

[0122] Alternatively, a piezoelectric element may be used to actuate the valve member, such an element being electrically or wirelessly connected to a controller and controlled by the controller as to when to contract or expand.

[0123] In some specific embodiments, the valve member is cylindrical and comprises a stationary valve member, which in turn comprises a corresponding cylindrical bushing within which the cylindrical valve member is arranged for displacement along the longitudinal axis of the bushing or for rotation about the longitudinal axis of the bushing.

[0124] The term cylindrical bushing is used to indicate that the bushing has a cylindrical cavity, usually but not necessarily of circular cross section, and the cylindrical valve member fits snugly into the cylindrical cavity of the bushing, so that no lubricating oil can flow between the cylindrical valve member and the cylindrical bushing, apart from a potentially minimal amount, which is negligible compared to the amount of lubricating oil injected into the cylinder just to lubricate the valve member inside the bushing.

[0125] System Benefits The system described herein has many advantages.

[0126] Providing a valve system and optionally an outlet valve system internal to the injector reduces the mass of the moving parts that need to be moved during actuation, which reduces the reaction time of the moving objects compared to prior art systems, thus providing the present system with improved reaction speed and corresponding precision in terms of timing and volume.

[0127] Since the injector typically has a length of less than a few times, for example about twice the thickness of the cylinder wall of such large engines, and extends through an opening in the cylinder wall, the distance from the valve system to the nozzle opening is usually about the thickness of the cylinder wall or even less. For example, the distance from the valve system to the nozzle opening is less than 20 cm, or even less than 10 cm, which is much shorter than the distance of 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 very short in comparison, and the valve system has a correspondingly short reaction time and precision.

[0128] Because the valve system is located within the injector housing and close to the nozzle, the injector has a short reaction time and can therefore achieve high accuracy in terms of injection timing and duration, which translates into injection volume. The high timing accuracy and fast reaction time allow the injection of lubricant in a single injection cycle to be performed in multiple partial injections. The injector has only a short and rigid flow path from the valve system to the nozzle, including, for example, the outlet valve system, so that uncertainty and inaccuracy in injection volume and timing are minimized, since minute compression and expansion of the oil in the relatively long conduits are avoided, along with the expansion of the conduits themselves.

[0129] For example, double injection can be performed so that two types of lubricant are mixed in the cylinder within a time interval before the engine piston passes the injector, especially when using the SIP principle.

[0130] Since no return line is required, the system only requires a single lubricant line to the injector, which minimizes installation costs and labor and minimizes the risk of failure, especially since engines are large and would require return lines several meters long, and also avoids inaccuracies in time and volume when closing the valve due to possible dead volumes in the return piping for the lubricant.

[0131] An outlet valve system with a check valve makes the injector stable against high pressure from the cylinder. A high degree of robustness against failure has been observed when the outlet valve system includes a check valve in or on the nozzle, which includes a valve member, e.g., a ball, that is spring-biased against a valve seat. These systems are simple and the risk of clogging is minimal. Also, the valve seat, especially if the valve member is a ball, tends to be self-cleaning and subject to little uneven wear, thus providing high reliability over time. The injector is therefore simple, reliable, fast and accurate, and easy to assemble from standard components with low manufacturing costs.

[0132] In conclusion, the particular valve system will operate at high speed due to its lightweight components. Furthermore, the components are relatively simple in construction, implying low manufacturing costs. In addition to these advantages, the valve system is reliable, robust and has a low risk of clogging. Also, since the components are subject to relatively small pressure loads, the valve system will have a long lifespan.

[0133] Optional parameters For example, the injector may comprise a nozzle having a nozzle opening of diameter D if the nozzle is circular, or an equivalent diameter D that is two times the square root of the nozzle opening area divided by Pi if the nozzle is not circular, where diameter D is at least 0.1 mm, and may be configured to emit a spray of atomized droplets, also referred to as oil mist.

[0134] The mist droplet spray is important in SIP lubrication, where the lubricant spray is repeatedly injected into the scavenging air inside the cylinder before the piston passes the injector during its movement towards TDC. In the scavenging air, the mist droplets are carried in the direction towards TDC due to the swirling motion of the scavenging air towards TDC, so that the mist droplets are spread and distributed on the cylinder wall. The mist atomization is due to the high pressure lubricant oil in the lubricant oil injector at the nozzle. For this high pressure injection, the pressure is higher than 10 bar, usually between 25 and 100 bar. As an example, it can range between 30 and 80 bar, and if necessary between 35 and 60 bar. The injection time is short, usually on the order of 5-30 milliseconds (msec). However, the injection time can be adjusted to 1 ms or even less than 1 ms, for example to 0.1 ms. Therefore, an inaccuracy of just a few milliseconds can have a negative effect on the injection profile, so a high accuracy is required, for example an accuracy of 0.1 ms, as mentioned above.

[0135] Viscosity also influences atomization. Lubricating oils used in marine engines usually have a typical kinematic viscosity of about 220 cSt at 40°C and 20 cSt at 100°C, which translates to a viscosity between 202 and 37 mPa·s. An example of a useful lubricating oil is the high-performance, marine diesel engine cylinder oil ExxonMobil® Mobilgard™ 570VS (or the phased-out 560VS). Other lubricating oils useful for marine engines are other Mobilgard™ oils as well as Castrol® Cyltech oils. Lubricating oils commonly used in marine engines have nearly identical viscosity profiles in the 40-100°C range, and are all useful for atomization when, for example, the nozzle orifice diameter is 0.1-0.8 mm, the lubricating oil has a pressure of 30-80 bar at the nozzle orifice, and the temperature is in the range of 30-100°C or 40-100°C. See also the published paper on this subject by Rathesan, Peter Jensen, Jesper de Claville Christiansen, Benny Endelt, Erick Appel Jensen, “Rheological Behavior of Lubricating Oils Used in Two-Stroke Marine Engines,” Industrial Lubrication & Tribology, 2017, Vol. 69, No. 5, pp. 750-753, https: / / doi.org / 10.1108 / ILT-03-2016-0075.

[0136] The invention will now be explained in more detail with reference to the drawings. [Brief description of the drawings]

[0137] [Figure 1] 1 is a schematic view of a portion of a cylinder in a first embodiment of an engine according to the present invention; [Diagram 2] FIG. 2 is a diagram of one embodiment of the injector shown in FIG. 1. [Figure 3a] FIG. 2 is a more detailed schematic diagram of the first embodiment of the control device shown in FIG. [Figure 3b] FIG. 2 is a more detailed schematic diagram of a second embodiment of the control device shown in FIG. [Figure 4]3 is a schematic diagram illustrating a further embodiment of a nozzle for the injector shown in FIG. 2. [Diagram 5] 2 is a schematic view corresponding to FIG. 1 of a part of a cylinder in a further embodiment of an engine according to the invention; [Figure 6] FIG. 6 is a schematic diagram of one embodiment of the injector shown in FIG. 5. [Figure 7] FIG. 7 is an enlarged cross-sectional view of the inlet valve housing of the injector shown in FIG. [Figure 8] 2 is a schematic view corresponding to FIG. 1 of a part of a cylinder in a further embodiment of an engine according to the invention; [Figure 9] FIG. 11 is a diagram regarding adjustment and calibration of the injector. [Figure 10] A control strategy for regulating the amount of lubricant is presented. [Figure 11] 1 illustrates the difference between a calibrated and an uncalibrated injector. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0138] Figure 1 shows half a cylinder 1 of a large slow-speed two-stroke engine, for example a marine diesel engine. The cylinder 1 comprises a cylinder liner 2 inside a cylinder wall 3. Inside the cylinder wall 3 a number of injectors 4 are provided for injecting lubricating oil into the cylinder 1. As shown, the injectors 4 are distributed circumferentially with the same angular distance between adjacent injectors 4, although this is not strictly required. Also possible are arrangements with axially displaced injectors, for example with every other injector displaced towards the top dead centre (TDC) of the piston relative to adjacent injectors, so the circumferential arrangement is not required.

[0139] Each injector 4 has a nozzle 5 with a nozzle opening 5' from which a fine mist-like spray 8 of micro-droplets 7 is emitted under high pressure into the cylinder 1.

[0140] For example, the nozzle opening 5' has a diameter of 0.1-0.8 mm, such as 0.2-0.5 mm, and at a pressure of 10-100 bar, for example 25-100 bar, optionally 30-80 bar or even 50-80 bar, atomizes the lubricating oil into a fine spray 8, which is in contrast to a dense jet of lubricating oil. A scavenging swirl 10 in the cylinder 1 transports and presses the spray 8 against the cylinder liner 2, such that a uniform distribution of the lubricating oil on the cylinder liner 2 is achieved. This lubrication system is known in the art as the Swirl Injection Principle, SIP.

[0141] However, other principles are also envisaged in connection with improved lubrication systems, such as injectors which direct a jet towards the cylinder liner.

[0142] Optionally, the cylinder liner 2 is provided with a free cut 6 to provide adequate space for the spray 8 or jet from the injector 4 .

[0143] In addition to the lubricant supply conduit 9, the injector 4 is connected to a controller 11 by a pressure control conduit 10. The lubricant supply conduit 9 is used to supply lubricant for injection. The pressure control conduit 10 supplies oil at high pressure to operate an internal pump system inside the injector 4, which will be described in more detail below.

[0144] 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, and 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 in the range of 50-80 bar.

[0145] The control device 11 is connected to a supply conduit 12 for receiving lubricant from a lubricant supply 25 which includes an oil pump, and to a return conduit 13, typically to an oil reservoir, for recirculating the lubricant as required. The lubricant pressure in the supply conduit 12 is greater than the pressure in the return conduit 13, for example at least twice as great.

[0146] The controller 11 delivers lubricating oil to the injectors 4 in precisely timed pulses that are synchronized with the piston movement in the cylinders 1 of the engine. For example, for synchronization, the controller system 11 is electronically connected, by wire or wirelessly, to a computer 11', which controls the components in the controller 11 for the lubrication delivery. Potentially, the computer 11' is part of the controller 11, for example provided in a single casing with the other components of the controller 11. Optionally, the computer monitors parameters relating to the actual state and operation of the engine, such as crankshaft speed, load and position, which in turn reveals the piston position in the cylinder.

[0147] Figure 2 shows the injector 4, and figures 3a and 3b show in more detail some possible embodiments of the control device 11. The dimensions are not to scale.

[0148] The syringe 4 comprises a syringe housing 4' with a syringe base 21 having a lubricant inlet port 4A for receiving lubricant from a lubricant supply conduit 9 and a pressure port 4B connected to a pressure control conduit 10 for causing the syringe 4 to release the lubricant.

[0149] The flow chamber 16 is part of the syringe housing 4' and holds the nozzle 5 against the syringe base 21. In the illustrated embodiment, the flow chamber 16 is provided as a hollow rigid rod. The flow chamber 16 is sealed to and held firmly against the syringe base 21 by an O-ring 22. A conduit 16' is provided from the rear to the front of the flow chamber 16 as a hollow passage inside the flow chamber 16. The conduit 16' communicates with the lubricant inlet port 4A and the nozzle 5 via the rear chamber 16A, the first intermediate chamber 16B, the second intermediate chamber 16C, and the front chamber 16D.

[0150] The injector 4 also comprises an outlet valve system 15 to regulate the lubricant dispensed through the nozzle opening 5'. Only when the pressure at the outlet valve system 15 exceeds a predetermined pressure, the outlet valve system 15 opens to release the lubricant into the engine cylinder 1. In the embodiment of Figure 2, the outlet valve system 15 is illustrated as part of the nozzle 5, although this is not strictly required.

[0151] The outlet valve system 15 comprises an outlet check valve 17. In the outlet check valve 17, an outlet valve member 18, exemplified as a ball, is prestressed by an outlet valve spring 20 towards an outlet valve seat 19. As soon as pressurized lubricant is supplied into the front chamber 16D, the prestress force of the outlet valve spring 20 is counteracted by the lubricant pressure, and when the pressure becomes higher than the spring force, the outlet valve member 18 is displaced from its outlet valve seat 19 and the outlet check valve 17 opens to inject lubricant into the cylinder 1 through the nozzle opening 5'.

[0152] As illustrated, the outlet valve spring 20 acts on the outlet valve member 18 in a direction away from the nozzle opening 5'. However, in this configuration, the direction of the force of the outlet valve spring 20 acting on the outlet valve member 18 can be different from the direction with respect to the nozzle opening 5', as long as the check outlet valve 17 with respect to the supply of lubricant to the nozzle opening 5' is closed when in the idle state during the injection phase. The closure of the check outlet valve 17 in the idle state prevents unintended flow of lubricant from the front chamber 16D through the nozzle opening 5' into the cylinder 1 during the injection phase.

[0153] The rear chamber 16A communicates with the inlet port 4A for receiving lubricant from the lubricant feed conduit 9. The rear chamber 16A communicates with the first intermediate chamber 16B via a rear passage 23A. The first intermediate chamber 16B communicates with the second intermediate chamber 16C via a passage 23B, which is a cylindrical opening around the actuator member 28, as described below. The second intermediate chamber 16C communicates with the front chamber 16D via a front passage 23C.

[0154] For convenience, the term "forward motion" is used for motion towards the nozzle opening 5', and motion in the opposite direction away from the nozzle opening 5' is called "rear motion".

[0155] The front chamber 16D is emptied through the nozzle opening 5' by forward movement of the reciprocating plunger member 29, which is spring-biased against the forward movement by a helical plunger spring 29B in the second intermediate chamber 16C. The plunger member 29 comprises a flow passage inlet 24 leading into an internal flow passage of the plunger member 29, a front flow passage 23C, for example in the center of the plunger member 29 as shown. During the forward movement of the plunger member 29, the front flow passage 23C is closed by the non-return plunger valve 26. In the illustrated embodiment, the non-return plunger valve 26 is illustrated as comprising a plunger valve ball 26A in a plunger valve seat 26B, against which the plunger valve ball 26A is prestressed by a plunger valve spring 26C.

[0156] Forward movement of the plunger member 29 is accomplished by forward movement of the actuator member 28 pressing against a head 29A of the plunger member 29. The actuator member 28 is rearwardly prestressed by a helical actuator spring 28A within the first intermediate chamber 16B.

[0157] In the illustrated exemplary embodiment, the actuator member 28 and plunger member 29 are separate elements, but may be combined as a single actuator-plunger, for example by having the actuator member 28 at one end and the plunger member 29 at an opposite end of the single element.

[0158] Forward movement of the actuator member 28 is accomplished by pressurized lubricant from pressure control port 4B which pressurizes the rear 28B of the actuator member 28 within pressure chamber 27 so that they move together.

[0159] The function of the injector 4 will be explained in more detail below. When the pressure control port 4B is supplied with pressurized oil, for example in the pressure range of 20-100 bar, the pressurized oil pushes the rear part 28B of the actuator member 28, moving it forward, thereby expanding the volume of the pressure chamber 27. When the actuator member 28 pushes the head 29A of the plunger member 29, the plunger member 29 moves forward together with the actuator member 28 against the forces of the actuator spring 28A and the plunger spring 29B. The forward movement of the plunger member acts on the lubricating oil in the front chamber 16D. Since the non-return valve 26 prevents the lubricating oil in the front chamber 16D from escaping backwards, the lubricating oil in the front chamber 16D is pressurized up to a predefined upper pressure limit, at which the outlet valve system 15 with the non-return outlet valve 17 opens to release the lubricating oil from the front chamber 16D through the nozzle opening 5' into the cylinder 1.

[0160] At the end of the injection phase, oil in the pressure control port 4B is exhausted, which causes the actuator spring 28A and the plunger spring 29B to push the actuator member 28 and the plunger member 29 back away from the nozzle 5. The rearward movement of the plunger member 29 reduces the pressure in the front chamber 16D, which in turn closes the non-return outlet valve 17 and draws oil from the second intermediate chamber 16C through the front flow passage 23C into the front chamber 16D, as the plunger check valve 26 is opened by the pressure reduction in the front chamber 16D. In this way, the check plunger valve 26 functions as a suction valve, as the pressure reduction in the front chamber 16D results in the replenishment of the lubricating oil in the front chamber 16D by suction through the check plunger valve 26. During this return movement of the actuator member 28 and the plunger member 29, the lubricant in the second intermediate chamber 16C is replenished from the first intermediate chamber 16B, which in turn is filled with lubricant from the rear chamber 16A which receives lubricant through the lubricant inlet port 4A.

[0161] For proper functioning, the lubricant inlet port 4a is supplied with lubricant at constant pressure from the lubricant feed conduit 9, and the pressure control port 4B is supplied with pressurized oil intermittently for each injection cycle from the pressure control conduit 10. The pressure at the pressure control port 4B rises during the injection phase and falls at idle between injection phases.

[0162] When the forward force acting on the actuator member 28 by the oil pressure in the pressure chamber 27 at idle is less than the resultant rearward force by the actuator spring 28A and the plunger spring 29B, the actuator member 28 and the plunger member 29 are returned fully to their rearmost possible position shown in Figure 2. Thus, a full stroke of the plunger member is achieved by intermittently varying the oil pressure at the pressure control port 4B between a maximum pressure and a lower pressure, for example the pressure of the lubricating oil in the lubricating oil feed conduit 9 or a lower pressure.

[0163] However, the actuator member 28 and plunger member 29 can be held offset from their rearmost position by adjusting the pressure in the pressure control port 4B and the pressure chamber 27 to an offset pressure level that creates a force acting on the actuator such that the springs 28A and 29B are not fully extended during the rearward movement of the actuator member 28 and plunger member 29 but are held in a slightly compressed state. This is possible because the force of the springs 28A and 29B varies with the compressed length and generally follows a linear dependence on the displacement of the actuator member from its rearmost position. The offset pressure level is less than the pressure level required to open the check outlet valve 17 to allow injection.

[0164] In principle, the injector 4 can be supplied with lubricant from one lubricant source at the inlet port 4A and can be supplied with pressurized oil or other pressurized liquid from an entirely different source, however, typically, for simplicity and convenience, the pressurized oil at the pressure control port 4B can be supplied from the same source as the lubricant at the inlet port 4A, but at higher pressure, for example by means of a pressure intensifier.

[0165] An exemplary embodiment of a method for achieving intermittent pressure variation at pressure control port 4B is described below with reference to the controller 11 shown in Figures 3a and the alternative embodiment of Figure 3b. However, the controller of Figures 3a and 3b is merely an exemplary embodiment, and the injector of Figure 2 is unrelated to the controller shown in Figures 3a, 3b and 4 and can function with other types of controllers.

[0166] In the embodiment of Figure 3a, the controller 11 comprises a toggle valve 30 having a toggle valve inlet port 30A connected to the supply conduit 12, a toggle valve outlet port 30B connected to the pressure control conduit 10 for communication with the injector pressure control port 4B, and a toggle valve return port 30C connected to the return conduit 13. Between the toggle valve return port 30C and the return conduit 13 is shown a pressure control valve 31, which will be described in more detail below and is optional.

[0167] The toggle valve 30 includes a first toggle closure element 32A and a second toggle closure element 32B that are rigidly coupled and arranged to reciprocate between a first state in which the toggle valve inlet port 30A communicates with the toggle valve outlet port 30B, and a second state in which the toggle valve outlet port 30B communicates with the toggle valve return port 30C. The reciprocating movement is indicated by arrow 33. In Figures 3a and 3b, only the second state is shown. For example, the toggle valve 30 may be a three-way valve as shown, and potentially a solenoid valve.

[0168] During the injection phase, the toggle valve 30 is in a first state, where high pressure lubricant from the supply conduit 12 is supplied to the pressure control port 4B of the injector 4, forcing the actuator member 29 forward and causing the injection of lubricant into the cylinder 1. At the end of the injection phase, the toggle member 30 moves to a second state as shown, and lubricant from the pressure control port 4B is exhausted through the toggle valve 30 and out the toggle valve return port 30C into the return line 13, allowing the actuator member 28 and plunger member 29 to return to the idle state. For example, the toggling action of the toggle member 32 is controlled in cooperation with the computer 11'.

[0169] Since the injector 4 comprises a pump system upstream of the nozzle 5, i.e. the plunger member 29, the lubricant oil supplied for injection does not have to be supplied at high pressure in the feed conduit 9. The pressure in the return conduit 13 is therefore typically in the range of 5-15 bar, which is sufficient to supply the lubricant oil via the feed conduit 9 to the inlet port 4A of the injector 4.

[0170] An optional dosage adjustment mechanism is also shown in Figure 2 in combination with Figures 3a and 3b. In this embodiment, pressure valve 31 comprises a pressure valve inlet port 31A connected to toggle valve return port 30C and a pressure valve outlet port 31B connected to return conduit 13. This means that toggle valve return port 31B is only connected to return conduit 13 through pressure valve 31, which is used to adjust the return pressure at toggle valve return port 30C.

[0171] In the illustrated embodiment, the pressure valve 31 includes a spring biased pressure adjustment member 31C whose preload is adjustable by a pretensioner 31D, such as a screw as shown. Although the pretensioner can be configured for manual adjustment, typically the pretensioner is adjusted by a motor or other type of actuator. Adjusting the pretensioner creates a greater or lesser preload on the spring biased pressure adjustment member 31C, which in turn adjusts the backpressure at the pressure valve inlet port 31A and the toggle valve return port 30C.

[0172] The adjusted back pressure at the toggle valve return port 30C determines the minimum pressure at the pressure control port 4B. Increasing this back pressure offsets the actuator member 28 and plunger member 29 from their rearmost positions. As the next injection phase starts its forward movement from this offset position, the stroke of the plunger member 29 will be shorter than if it started from the rearmost position. Thus, by adjusting the back pressure with the pressure valve 31, the stroke of the syringe 4 can be precisely adjusted and the amount of lubricant injected into the cylinder 1 can be correspondingly adjusted. The rearmost positions of the actuator member 28 and plunger member 29 are shown in FIG. 2.

[0173] Typically, one toggle valve 30 is provided for a group of syringes, e.g. all syringes of a cylinder. However, in alternative embodiments, one toggle valve 30 is provided for each syringe 4. If an optional pressure valve 31 is included in the system to adjust the stroke of the plunger member 29 and the injection volume, it is typically provided for the group of syringes 4. However, it is also possible to provide one pressure valve 31 for each syringe 4.

[0174] As is evident from the above embodiment, the lubricant oil feed conduit 9 communicates with the return line 13. In the illustration of FIG. 3a, the return conduit 13 enters the control device 11 and the feed conduit 9" exits the control device 11. This is also shown in FIG. 1 by the solid line 9", which is connected in its extension to the feed conduit 9. If the control device 11 is an additional unit, it will have at least four conduit connectors.

[0175] However, this is not essential. Optionally, the control device 11 comprises a return outlet line 34 connected to the return conduit 13 as shown in Fig. 3b. In this case, the return conduit 13 communicates directly with the feed conduits 9' and 9. This embodiment is shown in Fig. 1 by a separate dotted line 9', which is connected in its extension to the feed conduit 9. In this case, the return conduit 13, which is in the extension of the feed conduits 9 and 9', supplies lubricant directly to the lubricant inlet port 4A of the syringe 4 for injection into the cylinder, and the control device 11 is bypassed.

[0176] FIG. 4 shows a second alternative embodiment of the outlet valve system 15. The generalized principle of the outlet valve system 15 is similar to that disclosed in WO 2014 / 048438. This reference also provides additional technical details of the injector presented here as well as an explanation of its function, which will not be repeated here for convenience. A nozzle opening 5' is provided at the tip of the nozzle 5 for discharging the lubricating oil. Inside the cavity 40 of the nozzle 5 is provided an outlet valve member 18, which comprises a stem 41 and a cylindrical seal head 42 slidably disposed in a cylindrical cavity 43 of the nozzle tip 44. The position of the valve member 18 is prestressed rearwardly away from the nozzle tip 44 by a spring 45 and offset forwardly by oil pressure acting on the rear 47 of the stem 41 via a passage 46, which acts against the spring force. The nozzle opening 5' is sealingly covered by the seal head 42 which abuts the cylindrical cavity 43 at the nozzle tip 44 unless the nozzle member 18 is forced forward so that the seal head 42 slides past the nozzle opening 5' and lubricating oil flows from the internal cavity 46 and is expelled through the nozzle opening 5'.

[0177] The following figures are non-limiting examples of possible operating pressures: The pressure in the return conduit 13 and in the feed conduit 9 is 10 bar. The pressure in the supply conduit 12 is 40 bar. The outlet valve 15 opens at 37 bar so that the lubricant is injected at 37 bar. The springs 28A and 29B are configured to push the plunger member 29 and the actuator member 28 back to their full rearward position when the pressure at the pressure control port 4B in the idle state during the injection phase is 10 bar. The pressure valve is adjustable to a pressure of 10-30 bar, for example 20 bar, which is far below the injection pressure of 37 bar, but is high enough to supply a pressure in the pressure chamber 27 high enough so that the actuator member 28 does not return to its full rearward position but remains at a certain distance from it. Adjusting this distance by adjusting the pressure in the range of 10-30 bar adjusts the injection volume in the anterior chamber 16D because the smaller the forward movement during the injection phase, the greater the offset of the plunger member 29 from its rearmost position at the start of the injection phase.

[0178] Optionally, the injection volume is controlled by a flow meter inserted in the feed conduit 9 for the group of injectors or for each single injector 4. The flow meter measures the flow (mass and / or volume) and is then used to monitor that the injector(s) is / are working properly.

[0179] The injection system with the injector 4 and the control device 11 as described above is easy to install and replace. It is a relatively low-cost technical solution, despite being robust and stable. In particular, the injection volume can be precisely adjusted. Also, the system does not have electrical wiring to or from the injector 4, which makes it robust against heat, whereas electrical wiring may have an insulating layer that melts with heat.

[0180] The above embodiment is known from WO 2019 / 114905. However, the present engine differs in that it is equipped with a flow meter 35. The flow meter is intended to be used to measure the flow of lubricating oil in the lubricating oil feed conduit 9.

[0181] The signal from the flowmeter relating to the actual flow is then converted to an actual quantity in the control device, the calculated actual quantity is compared to the target value, and the control device then controls the injector to adjust its settings to regulate the amount of lubricant injected for the particular operating mode to the target value.

[0182] Figure 5 shows half a cylinder 1 of a large slow-speed two-stroke engine, for example a marine diesel engine. The cylinder 1 comprises a cylinder liner 2 inside a cylinder wall 3. Inside the cylinder wall 3 a number of injectors 4 are provided for injecting lubricating oil into the cylinder 1. As shown, the injectors 4 are distributed circumferentially with the same angular distance between adjacent injectors 4, although this is not strictly required. Also possible are arrangements with axially displaced injectors, for example with every other injector displaced towards the top dead centre (TDC) of the piston relative to adjacent injectors, so the circumferential arrangement is not required.

[0183] Each injector 4 has a nozzle 5 with a nozzle opening 5' from which a fine mist spray 8 is emitted under high pressure into the cylinder 1.

[0184] For example, the nozzle opening 5' has a diameter of 0.1-0.8 mm, such as 0.2-0.5 mm, and at a pressure of 10-100 bar, for example 25-100 bar, optionally 30-80 bar or even 50-80 bar, atomizes the lubricating oil into a fine spray 8, which is in contrast to a dense jet of lubricating oil. A scavenging swirl 14 in the cylinder 1 transports and presses the spray 8 against the cylinder liner 2, such that a uniform distribution of the lubricating oil on the cylinder liner 2 is achieved. This lubrication system is known in the art as the Swirl Injection Principle, SIP.

[0185] However, other principles are also envisaged in connection with improved lubrication systems, such as injectors which direct a jet towards the cylinder liner.

[0186] Optionally, the cylinder liner 2 is provided with a free cut 6 to provide adequate space for the spray 8 or jet from the injector 4 .

[0187] The injectors 4 receive lubricating oil from an engine lubricating oil supply 25, e.g. from an oil circuit, including potentially a lubricating oil pump that raises the pressure of the lubricating oil to a suitable level, via a feed conduit 9, typically a common feed conduit 9. For example, the pressure in the feed conduit 9 may be in the range 25-100 bar, optionally 30-80 bar, which is a typical pressure range for a SIP injector.

[0188] The injectors 4 are provided with an electrical connector 110' for electrical communication with the controller 11 via an electrical cable 110. As mentioned above, the injectors can alternatively communicate wirelessly with the controller 11. The controller 11 sends electrical control signals to the injectors 4 to control the injection of lubricant by the injectors 4 through the nozzle 5. As shown, one cable 110 is provided for each injector 4, allowing individual control of the injection of each injector. However, it is also possible to provide one electrical cable 110 from the controller 11 to all injectors 4, so that all injectors 4 receive electrical control signals via a single electrical cable and inject at the same time. Alternatively, it is also possible to provide one electrical cable 110 from the controller 11 to a subgroup of injectors, for example 2, 3, 4, 5 or 6 injectors, so that a first subgroup is controlled by the controller via the first cable 10 and a second subgroup is controlled via the second cable 110. The number of cables and subgroups is selected depending on the preferred configuration.

[0189] A flow meter 35 is connected to the lubricant feed conduit 9 and to an electrical cable 110 and is arranged to measure the flow of lubricant to each injector 4 or each subgroup of injectors.

[0190] The electrical control signals from the controller 11 to the injectors 4 are supplied in precisely timed pulses synchronized with the piston movement in the engine cylinders 1. For example, for synchronization purposes, the controller system 11 comprises or is electronically connected, by wire or wirelessly, to a computer 11' which monitors parameters relating to the actual state and operation of the engine, such as, for example, crankshaft speed, load and position, which in turn reveals the position of the piston in the cylinder.

[0191] The above embodiment is known from WO 2019 / 114905. However, the present engine differs in that it is equipped with a flow meter 35. The flow meter is intended to be used to measure the flow of lubricating oil in the lubricating oil feed conduit 9.

[0192] Figure 6 shows a main schematic diagram of the injector 4. Figure 6 is a schematic diagram that includes three different views of an exemplary injector: a top view, an end view and a cross-sectional side view.

[0193] The injector 4 comprises a lubricant inlet port 112 for receiving the lubricant from the lubricant feed conduit 9. The inlet port 112 is provided in an inlet valve housing 121 which comprises an inlet valve system 113 in communication with the inlet port 112 for regulating the amount of lubricant received from the lubricant feed conduit 9 during a lubrication phase. The injector 4 also comprises an outlet valve system 115 for regulating the lubricant dispensed through the nozzle opening 5'. A rigid flow chamber 116 connects the inlet valve system 113 with the outlet valve system 115 for flowing the lubricant to the nozzle 5. In the illustrated embodiment, the flow chamber 116 is provided as a hollow rigid rod. The flow chamber 116 is sealed against the inlet valve housing 121 of the inlet valve system 113 by an O-ring 122 and is held firmly against the inlet valve housing 121 by a flange 123 bolted to the inlet valve housing 121 by means of bolts 124.

[0194] FIG. 7 is a close-up of the inlet valve system.

[0195] 7 shows the inlet valve system 113 in more detail. Inside the inlet valve housing 121, a check inlet valve 125 includes an inlet valve member 126 that is prestressed by an inlet valve spring 128 toward an inlet valve seat 127. The inlet valve member 126 is illustrated as a ball, but different shapes would work, such as oval, conical, flattened, or cylindrical. When the inlet valve member 126 is displaced from the inlet valve seat 127 against the force of the inlet valve spring 128, lubricant flows from the inlet port 112 along the inlet valve spring 128, past the inlet valve member 126 and the inlet valve seat 127, and into a passageway 129 on the opposite side of the inlet valve member 126. From the flow passage 129, the lubricant flows through a passage 130 and into a hollow portion 116' of the flow chamber 116 for flow to an outlet valve system having similar generalized principles as those disclosed in WO 2014 / 048438, which reference also provides additional technical details of the injector presented herein as well as an explanation of its function, which will not be repeated here for convenience.

[0196] A pusher member 131, exemplified as a push rod, is reciprocated within the flow passage 129 to displace the inlet valve member 126 (ball). The pusher member 131 is not fixed to the inlet valve member 126, but rather to a reciprocating solenoid plunger 133 driven by a solenoid coil 132. The solenoid plunger 133 is retracted by a plunger spring 134 when in an idle state. When the solenoid coil 132 is energized by an electric current, the solenoid plunger 133 moves forward against the force of the plunger spring 134 until it stops against a plunger stop 135. The movement of the solenoid plunger 133 causes the pusher member (push rod) 131 to push the inlet valve member (ball) 26 away from the inlet valve seat 127, allowing lubricant to flow through the inlet check valve 125 and into the flow chamber 116.

[0197] In an advantageous embodiment, in the idle state, the pusher member (push rod) 131 is retracted a predetermined distance from the inlet valve member (ball) 126 so that there is a free travel distance between the pusher member 131 and the inlet valve member 126. When the solenoid coil 132 is energized, the pusher member 131 is accelerated by the solenoid coil 132 over the free travel distance before colliding with the inlet valve member 126 after an initial acceleration. This results in a rapid displacement of the inlet valve member 126 from the inlet valve seat 127 compared to the situation in which the inlet valve member 126 moves together with the pusher member 131 during the initial part of the acceleration. The rapid displacement of the inlet valve member 126 is consequently advantageous for the precise timing of the start of the lubricating oil injection into the cylinder 1. Optionally, the free travel distance is adjustable by an adjustment screw 136 at the end of the solenoid plunger 133.

[0198] After the injection phase, the lubricant supply from the inlet port 112 to the nozzle 5 is stopped by interrupting the current to the solenoid coil 132 which causes the solenoid plunger 133 to be pushed back by the plunger spring 134 and the inlet valve member 126 returns to its tight inlet valve seat 127 for the idle phase of the injection cycle.

[0199] The amount of lubricant is controlled by a flow meter and a controller / computer makes it possible to adjust the amount of lubricant and to calibrate the injector.

[0200] Figure 8 corresponds to figure 1 and shows a further embodiment of a cylinder 1 half of a large slow-running two-stroke engine, for example a marine diesel engine. This embodiment is equipped with an oil injector, which may be an HJ Smartlube 4.0E injector. The injector 4 is connected to a cylinder manifold 203 equipped with a flow meter. The cylinder manifold equipped with the flow meter is connected to the control device 11 via a communication line 211 for the flow meter feedback signal. The control device 11 may be a local cylinder control device connected to the central control device 208 via a communication line 210.

[0201] The cylinder manifold 203 equipped with the flow meter is connected to a pump unit 205. The pump unit 205 is connected to the lubricant supply 25 via the supply conduit 12.

[0202] The pump unit 205 is connected to the cylinder manifold (common rail) via a pressurized oil delivery line 214 and supplies lubricating oil to the injectors 4 .

[0203] An injector signal bus 212 connects the controller 11 with the injectors for regulating the amount of lubricant and for performing injector calibration.

[0204] Figure 9 is a diagram for explaining the adjustment of the injector 4 in the embodiment shown in Figure 8. The signal from the flow meter 203 is sent to the controller 11 via communication line 211. Furthermore, the injector 4 receives control signals from the controller 11 via an injector signal bus 212 for its adjustment and calibration. The signal from the flow meter is fed into a feedback control algorithm 215, which is stored in the controller 11 and used to define the injector signal sent to the injector 4.

[0205] Figure 10 shows the control strategy used by the controller. 36 is the desired lubricant quantity and 37 is the calculated actual lubricant quantity. A signal 38 from the flow meter is sent to the controller 11. Calculations are performed in the controller 11 and a control signal 39 is sent to the injector 4 to obtain an adjustment that ensures the actual lubricant quantity 37 matches the desired lubricant quantity.

[0206] 11 shows the difference between a calibrated injector 41 and an uncalibrated injector 40. From the figure, it can be seen that the uncalibrated injector 40 has a larger deviation than the calibrated injector 41. [Explanation of symbols]

[0207] 1 cylinder 2 Cylinder Liner 3 Cylinder Wall 4 syringe 4' Injector Housing 4A Oil Injector 4 Inlet Ports 4B Pressure control port of oil injector 4 5 Nozzles 5' Nozzle opening 6 Free cut of liner 7. Atomized spray from a single injector 4 8 Swirling spray 9 Lubricating oil supply pipe 10 Pressure Control Conduit 11 Control device 11' Computer 12 Supply conduit 13 Return conduit 14 Swirl in a cylinder 15 Injector 4 Outlet Valve System 16 A flow chamber connecting the inlet valve system with the outlet valve system 16' Hollow portion of flow chamber 16 16A Posterior chamber 16B First Intermediate Room 16C Second Intermediate Room 16D Antechamber 17 Outlet check valve exemplified as outlet ball valve 18 Outlet valve member exemplified as a ball 19 Outlet valve seat 20 Outlet valve spring 21 Syringe base 22 O-ring at end of flow chamber 16 23A: A rear flow passage in the actuator member 28 connecting the rear chamber 16A with the first intermediate chamber 16B 23B Intermediate flow passage between the first intermediate chamber 16A and the second intermediate chamber 16B 23C Front flow passage in plunger 29 between second intermediate chamber 16B and front chamber 16D 24 Channel inlet to front channel 23C 25 Lubricating oil supply section 26 Check Plunger Valve 26A Plunger Valve Ball 26B Plunger valve seat on which the plunger valve ball 26A is prestressed 26C a plunger valve spring that prestresses the plunger valve ball toward the plunger valve seat 26B 27 Rear 28B pressure chamber 28 Actuator member for the plunger head 29' of the plunger member 29 28A Actuator spring acting backwards on the actuator 28B Rear of actuator member 29 Plunger member 29A Plunger member head 29B Plunger spring in second intermediate chamber 16C 30 Toggle valve 30A toggle valve inlet port 30B Toggle valve outlet port 30C Toggle valve return port 31 Pressure control valve 31A Pressure valve inlet port 31B Pressure valve outlet port 31C Pressure regulator (e.g., spring-loaded pressure regulator for injection phase) 31D Pressure valve 31 pretensioner 32 Toggle member 32A: first toggle closure element of toggle member 32 32B second toggle closure element of toggle member 32 33 Arrows showing reciprocating movement of toggle members 34 Return outlet line from control device 11 to the return conduit 35 Flow meter 36 Desired amount of lubricant 37 Calculated Actual Lubricant Quantity 38 Signal from flow meter 39 Control Signals 40 Uncalibrated Injector 41 Calibrated injectors 112 Lubricant inlet port of injector 4 113 Injector 4 Inlet Valve System 114 Swirl in a Cylinder 115 Injector 4 Outlet Valve System 116 a flow chamber connecting the inlet valve system 113 with the outlet valve system 116' Hollow portion of flow chamber 16 118 Outlet valve member 119 Outlet valve seat 120 Outlet valve spring 121 Inlet valve housing of inlet valve system 115 122 O-ring at end of flow chamber 116 123 Flange for holding flow chamber 124 Bolts for holding flange 123 and flow chamber to inlet valve housing 121 125 Inlet check valve exemplified as an inlet ball valve 126 Inlet valve member exemplified as a ball valve 127 Inlet valve seat 128 Inlet valve spring 129 Inlet valve system flow path 130 Passage from flow passage 129 to hollow portion 116' of flow chamber 16 131 A pushing member fixed to the solenoid plunger, exemplified as a rod 132 Solenoid coil 133 Solenoid plunger in solenoid coil 131 134 Plunger spring 135 Plunger Stop 136 Adjustment screw for adjusting free travel distance 203 Cylinder manifold with flow meter 205 Pump Unit 208 Central Control Unit 210 Communication line between local cylinder control device and central control device 211 Communication line for flowmeter feedback signal 212 Injector Signal Bus 214 Pressurized oil delivery line 215 Feedback Control Algorithm

Claims

1. A large, slow-running, two-stroke engine comprising a cylinder (1) with a reciprocating piston therein and a lubrication system, the lubrication system comprising: a lubricating oil supply unit (25); a plurality of lubricant injectors (4) distributed along the circumference of the cylinder (1) for injecting lubricant into the cylinder (1) at various positions along the circumference of the cylinder (1) during an injection phase; a lubricant supply conduit (12) and a lubricant return line (13) connecting said lubricant supply (25) with said lubricant injector (4); at least one flow meter for measuring the flow of said lubricant; Equipped with The engine is a control device (11) for controlling the amount and timing of injection of the lubricant by at least one of the lubricant injectors (4); a computer (11') to which the control device is connected; Furthermore, Each of said lubricant injectors (4) comprises: an inlet port (4A) fluidly connected to said lubricant supply conduit (12) for receiving lubricant therefrom; a nozzle (5) having a nozzle opening (5') extending into the cylinder (1) and configured to inject lubricating oil from the inlet port (4A) into the cylinder (1) during the injection phase; an adjustable valve in the nozzle (5) for opening and closing the flow of lubricant from a pressure chamber in the injector to the nozzle opening (5') during an injection cycle; Equipped with one flow meter for all injectors in the engine, one flow meter for all injectors of a cylinder, or one flow meter for each injector of the engine; the controller is configured to convert the measured actual flow into an actual quantity; the engine further includes a plurality of desired values, typically defined as delivery rates, for the amount of lubricant to be injected in a particular operating mode, the desired values ​​being stored in a database within the control device; the controller is configured to compare the calculated actual quantity with a desired value and control the injector to adjust its settings to obtain the desired value for the amount of lubricant to be injected in a particular operating mode; the control device is configured to calibrate the injector by measuring the amount of lubricant injected at different injection phases, mapping the results, and using the results to determine the injection phase of the injector to obtain a desired amount of lubricant during injection; A large, low-speed, two-stroke engine.

2. 2. A large, slow-running, two-stroke engine according to claim 1, wherein the lubrication oil system is selected from a mechanically driven system, a hydrostatically driven system and a common rail system.

3. 3. A large, slow-running, two-stroke engine according to claim 1 or 2, wherein the flow meter is provided in the lubricating oil supply conduit (12) connected to the injector.

4. 3. A large, slow-running, two-stroke engine according to claim 1 or 2, wherein the flow meters are integrated into the injectors, with one flow meter located per injector of the engine.

5. 3. A large, slow-running, two-stroke engine according to claim 1 or 2, wherein the engine is equipped with a hydraulically actuated inlet valve system.

6. 3. A large, slow-running, two-stroke engine according to claim 1 or 2, wherein the engine is equipped with an electrically operated inlet valve system.

7. A method of lubricating a large, slow-running, two-stroke engine having a cylinder (1) with a reciprocating piston therein and a system comprising: a lubricating oil supply unit (25); a plurality of lubricant injectors (4) distributed along the circumference of the cylinder (1) for injecting lubricant into the cylinder (1) at various positions along the circumference of the cylinder (1) during an injection phase; a lubricant supply conduit (12) and a lubricant return line (13) connecting said lubricant supply (25) with said lubricant injector (4); at least one flow meter for measuring the flow of said lubricant; Equipped with The engine is a control device (11) for controlling the amount and timing of injection of the lubricant by at least one of the lubricant injectors (4); a computer (11') to which the control device is connected; Furthermore, Each of said lubricant injectors (4) comprises: an inlet port (4A) fluidly connected to said lubricant supply conduit (12) for receiving lubricant therefrom; a nozzle (5) having a nozzle opening (5') extending into the cylinder (1) and configured to inject lubricating oil from the inlet port (4A) into the cylinder (1) during the injection phase; an adjustable valve in the nozzle (5) for opening and closing the flow of lubricant from a pressure chamber in the injector to the nozzle opening (5') during an injection cycle; Equipped with The method includes, in a cyclic operation: During the injection phase, supplying pressurized liquid to the inlet port of the injector, applying a force to the valve, which moves a valve body in the injector (4) and, when the pressure rises above a predetermined upper limit, pumping a predetermined amount of lubricating oil into the cylinder (1) through the nozzle opening (5'); after the injection phase, retracting the valve body by expelling pressurized liquid from the injector; During retraction, refilling the pressure chamber in the injector with lubricant for a next injection phase; providing one flow meter for all injectors of the engine, one flow meter for all injectors of the cylinder, or one flow meter per injector of the engine; measuring the flow of the lubricant with the at least one flow meter; converting the measured actual flow into an actual quantity within the controller; Including, The method comprises: providing the engine with a plurality of desired values, typically defined as delivery rates, for the amount of lubricant to be injected in a particular operating mode, the desired values ​​being stored in a database within the controller; comparing the calculated actual amount with the desired value; controlling said injector to adjust its settings in order to adjust said actual quantity to said desired value for the amount of lubricant injected in a particular mode of operation; performing adjustments of the lubricant quantity continuously at different time intervals varying between 10 milliseconds and 10 minutes, the continuous adjustments comprising adjusting the lubricant quantity at different sample intervals varying from one adjustment per injection to adjustments based on 100 previous injections; or performing discontinuous adjustment of the lubricant amount at time intervals between 1 minute and 30 days, preferably between 1 hour and 30 days, more preferably between 1 day and 30 days, said discontinuous adjustment comprising calibration of the injector, said calibration being performed by measuring the amount of lubricant injected at different injection phases to obtain a desired amount of lubricant at injection, mapping the results and using said results to determine the injection phase of the injector; A method comprising:

8. 8. The method of claim 7, wherein the calibration of the injector is performed over an operating spectrum of the injector, the operating spectrum being typically between 0 and 100 ms.

9. 9. The method according to claim 7 or 8, wherein the method includes the step of implementing an automatic inspection program to control the injectors of the cylinders to supply a desired and sufficient amount of the lubricating oil.

10. 10. The method of claim 9, wherein calibration of the injector in the event of an incorrect amount of lubricant being dispensed is performed manually or automatically.

11. The method of claim 9 , wherein the automated testing program includes correcting the calibration.

12. 9. The method according to claim 7 or 8, wherein the regulation of the lubricant quantity is controlled by feedback control / regulation, such as PID regulation or more advanced model-based regulation.

13. 9. A method according to claim 7 or 8, including storing adjustment values ​​in a database within the controller.

14. 9. A method according to claim 7 or 8, including storing calibrated timing values ​​for each injector in a database within the control unit.

15. 2. A large, slow-running, two-stroke engine according to claim 1, wherein the engine is used for SIP injection into the cylinders of large marine engines or power plant combustion engines at lubricating oil pressures in the range of 25 bar to 100 bar.

16. 8. The method of claim 7, wherein the method is used for SIP injection into the cylinders of a marine engine or a power plant combustion engine at lubricant oil pressures in the range of 25 bar to 100 bar.

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