阅读说明：本技术 一种优化大型低速二冲程发动机中润滑的方法 (Method for optimizing lubrication in large-scale low-speed two-stroke engine ) 是由 皮尔·巴克 尼古拉·克里斯滕森 于 2019-07-04 设计创作，主要内容包括：一种优化大型低速二冲程发动机中润滑的方法,通过此方法将现有的润滑系统改进为更频繁的喷射和每次喷射时更少的润滑剂用量。(A method of optimizing lubrication in a large low speed two stroke engine by which existing lubrication systems are improved to more frequent injections and less lubricant usage per injection.)

1. A method of improving lubrication in a large low-speed two-stroke engine, which engine comprises a cylinder (1), which cylinder (1) is provided with a reciprocating piston and a number of injectors (4) distributed along the circumference of the cylinder (1) for injecting lubricant into the cylinder (1) at different positions of the circumference during an injection phase; the engine further comprises a lubrication system for providing lubricant to the injector (4) during the injection phase;

wherein the lubrication system comprises a lubricator (11), the lubricator (11) being piped to each injector via a lubricant supply pipe (9) to provide pressurised lubricant to each injector via the lubricant supply pipe (9) during an injection phase;

wherein the lubricator (11) is of the type provided with a hydraulically driven actuator piston (123) reciprocating along the stroke length in a housing (101); wherein the lubricator (11) further comprises a stroke length (112) adjustment mechanism (110) arranged to variably adjust the stroke length (112) of the reciprocating hydraulically driven actuator piston (123) only between a minimum stroke length and a maximum stroke length;

wherein the lubricator (11) further comprises a plurality of spray plungers (119) slidably arranged in respective dosing channels (115), wherein the spray plungers (119) are connected with the actuator piston (123) so as to be moved by the actuator piston (123) over a stroke length and thereby pressurize lubricant at dosing channel distances in the dosing channels (115) to expel pressurized lubricant from the dosing channels (115) via the one-way valve (102) and into the injector (4) via the supply conduit (9) for injecting lubricant into the engine cylinder (1); wherein the dosing channel distance defines an amount of lubricant that is expelled from the dosing channel (115) during a spraying phase; wherein the ingredient passage distance is adjustable between a minimum ingredient passage distance and a maximum ingredient passage distance by adjusting a stroke length between a minimum stroke length and a maximum stroke length of the actuator piston (123);

wherein the oil injector (11) comprises an electric valve arranged to switch a hydraulic pressure level acting on the actuator piston (123) so as to hydraulically drive the actuator piston (123) reciprocally by switching the pressure level;

wherein the lubrication system comprises a controller (12) electrically connected to the electric valve (116) for controlling the timing of the switching of the injection phases by means of respective electric signals transmitted from the controller to the electric valve (116);

wherein the method comprises

-operating the engine lubricated by the lubricator (11) by injecting a first number of revolutions per revolution of the engine through the lubricant injector (4) under the control of the controller (12);

-stopping the engine to improve the lubrication system;

-improving the lubrication system;

-continuing to operate the engine with the modified lubrication system;

characterised in that the modification of the lubrication system comprises modifying the lubricator (11) by reducing the dosing passageway distance to less than the minimum dosing passageway distance and operating the engine lubricated by the modified lubricator (11) at a higher injection frequency for a second number of revolutions per engine revolution, wherein the second number is less than the first number, and the modified lubricator (11) is lubricated at a reduced dosing passageway distance and a correspondingly reduced amount of lubricant discharged from the dosing passageway (115) during each injection phase.

2. The method of claim 1, comprising adjusting the total lubricant consumption to be less than or equal to the lubricant consumption before the improvement in the lubrication system during ongoing operation of the engine using the improved lubricator.

3. The method according to claim 1 or 2, wherein the housing comprises an inner volume (114) for containing lubricant, and the dosing channel (115) comprises an inlet hole (113) in fluid communication with the inner volume for receiving lubricant from the inner volume (114) when the injection plunger (119) is in the retracted position; wherein the inlet aperture (113) has an aperture width between an aperture trailing edge and an aperture leading edge and is arranged to be closed by the injection plunger (119) after passing the aperture leading edge during movement of the injection plunger, such that further movement of the injection plunger (119) along an ingredient channel distance from the aperture leading edge to a most forward position of the injection plunger (119) is capable of pressurising and discharging lubricant contained in the ingredient channel (115) through the one-way valve (102), wherein the reduction of the ingredient channel distance comprises increasing the width of the inlet aperture (113) in the forward direction or arranging another inlet channel closer to the most forward position of the injection plunger (119).

4. The method according to claim 1 or 2, wherein the reduction of the ingredient passage distance comprises changing the stroke length of the actuator piston (123) to less than a minimum stroke length; and running the engine lubricated by the modified lubricator with a modified stroke length less than the minimum stroke length.

5. Method according to claim 4, characterized in that said injector (11) before the lubrication system modification comprises a feedback sensor arranged to measure a predetermined minimum displacement of the actuator piston (123) during the injection phase and for providing a feedback signal when the minimum displacement is measured; wherein the controller (11) is arranged to receive a feedback signal as confirmation of correct lubrication; wherein the improvement in the lubrication system comprises providing a feedback signal simulator (16) separate from the feedback sensor, electrically decoupling the feedback sensor from the controller (12), and providing a simulated feedback signal from the feedback signal simulator (16) to the controller (12) to simulate proper lubrication of the controller (12) despite the actuator piston (123) operating with a modified stroke length less than the minimum stroke length and less than a predetermined minimum displacement.

6. Method according to claim 4 or 5, characterized in that the stroke of the actuator piston (123) is defined by a front end stop (105) and a rear end stop (101), wherein the position of the front end stop (105) or the rear end stop (101) is defined by an adjusting mechanism, which is adjustable between a minimum position and a maximum position, wherein the minimum position defines a minimum stroke length and the maximum position defines a maximum stroke length; wherein the modification to the lubrication system comprises changing the minimum position to a modified position defining a modified minimum stroke length.

7. Method according to claim 6, characterized in that the position of the front end stop is defined by one end of a stroke length adjusting screw (121), which is adjusted along the stroke length (112) by rotating the stroke length adjusting screw (121); wherein the modification to the lubrication system comprises replacing the stroke length adjustment screw (121) with a longer modified adjustment screw (121) or adding material to the stroke length adjustment screw in the space between the stroke length adjustment screw (121) and the actuator piston (123) thereby reducing the stroke length (112).

8. Method according to claim 6, characterized in that the position of the front end stop is defined by one end of a stroke length adjustment screw (121), which is adjusted by rotating the screw; wherein the oil injector comprises a flange (107), the flange (107) being provided with a screw bearing for supporting a stroke length adjustment screw (112); and wherein the improvement to the lubrication system comprises replacing the flange (107) or removing material from the flange (107) by machining the flange (107) and thereby moving the screw bearing towards the actuator piston (123) and moving a nose stop (105) defined by the stroke length adjustment screw (121) towards the actuator piston (123) thereby changing the minimum position.

9. Method according to claim 8, wherein the adjusting screw (121) is adjustable by rotating in a thread (110) in the flange (107), wherein the improvement by machining the flange (107) means increasing the length of the thread (110) in the direction towards the actuator piston (123) thereby increasing the adjustment length of the adjusting screw (121), and wherein the method comprises moving the adjusting screw (121) closer to the actuator piston (123) thereby decreasing the stroke length (112) by rotating the adjusting screw (121) in the thread (110).

10. A method according to claim 9, characterized in that a motor is mounted on the screw (121) and that the method comprises rotating the adjusting screw (121) in the jet gap by means of the motor so as to change the stroke length (112).

11. Method according to any of the preceding claims, characterized in that the type of lubricant injector before modification is a filler pipe injector or a jet of a compact lubricant, and the method comprises replacing the lubricant injector with a SIP type injector (4) and continuously operating the engine with lubricant injection from the SIP injector and spraying atomized droplets of lubricant into a swirl of purge air in the cylinder, wherein the pressure of the lubricant from the SIP injector is in the interval 20 to 120 bar.

12. A method of improving a lubrication system for improving the lubrication of a large low-speed two-stroke engine of the type comprising a cylinder (1), said cylinder (1) having a reciprocating piston therein and a plurality of injectors (4) distributed along the circumference of the cylinder (1) for injecting lubricant into the cylinder (1) at different locations of the circumference during an injection phase; wherein the lubrication system is arranged to provide lubricant to the injector during an injection phase;

wherein the lubrication system comprises a lubricator (11), the lubricator (11) being provided with a connection for plumbing the lubricator (11) to each injector through a lubricant supply conduit (9) to provide pressurized lubricant to each injector through the lubricant supply conduit (9) during an injection phase;

wherein the lubricator (11) is of the type provided with a hydraulically driven actuator piston (123) reciprocating along the stroke length in a housing (101); wherein the lubricator (11) further comprises a stroke length adjustment mechanism arranged to variably adjust the stroke length of the reciprocating hydraulically driven actuator piston (123) only between a minimum stroke length and a maximum stroke length;

wherein the lubricator further comprises a plurality of spray plungers (119) slidably arranged in respective dosing channels (115), wherein the spray plungers (119) are connected with the actuator piston (123) so as to be moved by the actuator piston (123) over a stroke length and thereby pressurize lubricant at a dosing channel distance in the dosing channels (115) for discharging pressurized lubricant from the dosing channels (115) via the one-way valve (102) and via the supply conduit (9) into the injector (4) for injecting lubricant into the engine cylinder (1); wherein the dosing channel distance defines an amount of lubricant that is expelled from the dosing channel (115) during a spraying phase; wherein the ingredient passage distance is adjustable between a minimum ingredient passage distance and a maximum ingredient passage distance by adjusting a stroke length between a minimum stroke length and a maximum stroke length of the actuator piston (123);

wherein the lubricator (11) comprises an electric valve (116) arranged to switch the hydraulic pressure level acting on the actuator piston (123) so as to hydraulically drive the actuator piston (123) reciprocally by switching the pressure level;

wherein the lubrication system comprises a controller (12) electrically connected to the electric valve (116) for controlling the timing of the switching of the injection phases by means of respective electric signals transmitted from the controller to the electric valve (116);

characterized in that the method comprises modifying the lubricator (11) by reducing the dosing channel distance to less than the minimum dosing channel distance, thereby modifying the lubrication system.

13. The method of claim 12, wherein the decreasing of the ingredient passage distance comprises varying a stroke length of the actuator piston (123) to less than a minimum stroke length.

14. Method according to claim 13, characterized in that said injector (11) before the improvement of the lubrication system comprises a feedback sensor (120) arranged to measure a predetermined minimum displacement of the actuator piston (123) during the injection phase and for providing a feedback signal when the minimum displacement is measured; wherein the controller (11) is arranged to receive a feedback signal as confirmation of correct lubrication; wherein the improvement in the lubrication system comprises providing a feedback signal simulator (16) separate from the feedback sensor, electrically decoupling the feedback sensor (120) from the controller (12), and providing a simulated feedback signal from the feedback signal simulator (16) to the controller (12) to simulate proper lubrication of the controller (12) despite the actuator piston (123) operating with a modified stroke length less than the minimum stroke length and less than a predetermined minimum displacement.

15. A method according to claim 13, wherein the feedback sensor (120) is arranged to provide a feedback signal having a first type of feedback signal when the feedback sensor senses that the actuator piston (123) is moving from its position in an idle phase between injection phases thereof, and the feedback sensor (120) provides a second type of feedback signal only during an injection phase when the actuator piston reaches a predetermined minimum displacement; wherein the feedback signal simulator (16) provides a simulated second type of feedback signal to the controller (12) if a first type of signal is received from the feedback sensor (120) and not if no signal is received from the feedback sensor (120).

16. The method according to any of claims 13-15, wherein the stroke of the actuator piston (123) is defined by a front end stop (105) and a rear end stop (101), wherein the position of the front end stop (105) or the rear end stop (101) is defined by an adjustment mechanism, which is adjustable between a minimum position and a maximum position, wherein the minimum position defines a minimum stroke length and the maximum position defines a maximum stroke length; wherein the modification to the lubrication system comprises changing the minimum position to a modified position defining a modified minimum stroke length.

17. The method according to claim 16, wherein the position of the front end stop is defined by one end of a stroke length adjustment screw (121), adjusted along the stroke length (112) by rotating the stroke length adjustment screw (121); wherein the modification to the lubrication system comprises replacing the stroke length adjustment screw (121) with a longer modified adjustment screw (121) or adding material to the stroke length adjustment screw in the space between the stroke length adjustment screw (121) and the actuator piston (123) thereby reducing the stroke length (112).

18. A method according to any of claims 13-17, wherein the housing comprises an inner volume (114) for containing lubricant, and the dosing channel (115) comprises an inlet aperture (113) in fluid communication with the inner volume for receiving lubricant from the inner volume (114) when the injection plunger (119) is in the retracted position, the inlet aperture (113) having an aperture width between an aperture trailing edge (113b) and an aperture leading edge (113a), and being arranged to be closed by the injection plunger after passing the aperture leading edge during movement of the injection plunger (119), such that further movement of the injection plunger (119) along the dosing channel distance, from the aperture leading edge to a most forward position of the injection plunger (119), can pressurise and discharge lubricant contained in the dosing channel (115) through the one-way valve (102), wherein the reduction of the dosing channel distance comprises increasing the width of the inlet aperture (113) in the forward direction or arranging more forward Another inlet passage (113') proximal to the most forward position of the injection plunger (119).

Technical Field

The invention relates to a method for optimizing lubrication in a large low-speed two-stroke engine. Existing lubrication systems have been modified to achieve more frequent injections and a lower amount of lubrication oil per injection. Large low-speed two-stroke engines are for example marine engines or large engines in power plants.

Background

Due to environmental concerns, efforts are being made to reduce emissions from marine engines. This also relates to the stable optimization of the lubrication system of such engines, particularly in increasingly competitive situations. One of the economic aspects that is gaining increasing attention is the reduction of oil consumption, not only because of environmental protection, but also because this is an important component of the cost of operating ships. Despite the reduced amount of lubricating oil, there is also a concern about proper lubrication, as the life of the diesel engine should not be compromised by reduced fuel consumption. Therefore, stable improvement in lubrication is required.

For lubrication of large low speed two-stroke marine diesel engines, there are a number of different systems, including direct injection of lubricating oil on the cylinder liner or injection pipe on the piston rings.

Another relatively new approach compared to conventional lubrication is commercially known as the Swirl Injection Principle (SIP). The method is based on spraying atomized droplets of lubricant into a vortex of purge air in the cylinder. The spiraling upward flow causes the lubricant to be pushed toward Top Dead Center (TDC) of the cylinder and to be forced outward toward the cylinder wall as a thin, uniform layer. This is explained in detail in international patent applications WO2010/149162 and WO 2016/173601. Examples of SIP lubricant injector systems in marine engines are disclosed in international patent applications WO2002/35068, WO2004/038189, W02005/124112, W02010/149162, WO2012/126480, WO2012/126473, WO2014/048438 and W02016/173601. The injector comprises an injector housing in which a reciprocating valve member, typically a valve needle, is located. The valve member has, for example, a needle tip, and closes and opens a passage to the nozzle hole according to precise timing. In current SIP systems, atomized droplet sprays are achieved at pressures typically 35-65 bar, which are substantially higher than the oil pressures of less than 10 bar used in systems operating with compressed oil jets introduced into the cylinders. In some types of SIP valves, the high pressure of the lubricant also serves to move the spring-loaded valve member away from the nozzle bore against the spring force, thus causing high pressure oil to be released therefrom as atomized droplets. The blow out of oil causes the oil pressure on the valve member to decrease, whereupon the valve member returns to the home position and remains there until the next lubrication cycle when high pressure lubricant is again supplied to the lubricant injector.

In such large marine engines, a plurality of injectors are arranged in a circle around the cylinder and each injector includes one or more nozzle holes at the tip for delivering a lubricating jet or spray from each injector into the cylinder.

German patent document DE19743955B4 and its equivalent danish patent DK173288B1 disclose one of the more conventional methods of lubricating marine engines at present. It discloses a lubrication system in which a central controller supplies lubricant to the lubricators of each cylinder of a marine engine. The lubricator distributes lubricant to a plurality of lubricant injectors distributed about the circumference of the cylinder. The lubricator includes a housing in which a plurality of piston pumps are arranged in a circle and are driven in unison by a hydraulically driven actuator piston 123. Each piston pump includes an injection plunger 119 that pumps lubricant through a one-way valve to one of the injectors of the single cylinder. The hydraulically driven actuator piston 123 moves over an adjustable distance between its fixed rear end stop and a front end stop that is adjustable by an adjusting screw. The adjustment screw may be accessed from an end cap covering a flange of the housing through which the adjustment screw extends to rotate.

The system, which is widely distributed with respect to the injection of a compact lubricant jet into the cylinder of a marine engine and the injection of lubrication on the piston between the piston rings, is sold under the trade name Alpha lubricator (Alpha lubricator) by manen B & W Diesel Turbo charger (MAN B & W Diesel and Turbo).

FIG. 1 shows an example of an alpha oiler found on the web page http:// www.mariness.co.kr/02_ business/Doosan% 20 Retrofit% 20Seivice pdfPHPSESSIP ═ fd56da9de6eaca2f1f446512e84fcf 69. The figure is slightly modified with reference numerals to describe its principles in more detail.

Similar to DE19743955B4 and DK173288B1 mentioned above, alpha lubricator 100 comprises a housing 101 in which a plurality of injection plungers 119 are arranged in a circle and are driven in unison in common by a hydraulically driven actuator piston 123. Each injector plunger 119 is slidably disposed in the dosing channel 115 and receives lubricant from the interior volume 114 of the housing 101 through the inlet aperture 113. During the forward movement of the injection plunger 119, the inlet hole 113 is closed by the injection plunger 119, so that further forward movement of the injection plunger 119 pressurizes the lubricant contained in the remaining part of the dosing channel 115 and pumps it through the non-return valve 102 into the conduit 103 and into one of the injectors of a single cylinder. During the contraction of the actuator piston 123 caused by the pre-stressed spring 109, the injection plunger 119 contracts and creates a vacuum in the dosing channel 115, until after the front end of the injection plunger 119 has contracted past the inlet hole 113, lubricant can flow through the inlet hole 113 and re-fill the dosing channel 115.

The volume of lubricant pressurized by the jet plunger 119 in the dosing passage 115 and expelled through the check valve 102 is determined by the stroke distance of the jet plunger 119 from the inlet port 113 to the forwardmost position prior to retraction. During the movement of the actuator piston 123 over the stroke length, a first portion of the movement of the injection plunger 119 passes the inlet opening 113, and only after the injection plunger 119 has moved past the inlet opening 113 and closed it, will the lubricant be pressurized and expelled from the remaining distance of the dosing channel.

In this arrangement, the distance of the ingredient passage is less than the stroke length. However, the distance of the dosing channel, where the lubricant is pressurized and discharged, may also be equal to the stroke length, for example in case the lubricant is supplied through a non-return valve at the forefront of the dosing channel. An example of such a structure in a controller is disclosed in fig. 5 of DE19743955B 4.

The hydraulically driven actuator piston 123 moves over an adjustable distance between its fixed rear end stop 104 and a front end stop 105 which can be adjusted by means of an adjusting screw. The adjustment screw 121 can be turned by entering from the end cap 106 covering the flange 107 of the housing 101, through which the adjustment screw 121 extends. Flange 107 in alpha grease injector 100 supports a washer 122 and contains threads 110 for adjustment of an adjustment screw 121. The reciprocating actuator piston 123 is driven by the oscillating oil pressure in the volume 108 behind the actuator piston 123, with the solenoid valve 116 switching between two pressure levels in the volume 108 behind the actuator piston 123. Once the lower pressure level is reached, the spring 109 load presses the actuator piston 123 back to the back end stop. The solenoid valve 116 is regulated by a corresponding signal from the control unit.

As shown in fig. 1, a washer 122 is provided in the flange 107 behind the end cap 106 for the basic setting of the pumping stroke, where the head of the adjusting screw can be accessed for adjustment by rotation. Thus, there are two adjustment functions, namely basic adjustment by means of the washer 122 and adjustment by means of the adjusting screw 121. For the washer variation, the basic setting is bounded by the length of the thread 110 that receives the adjustment screw 121, and the adjustment screw 121 is rotated within the length of the thread 110 to make the adjustment. The length of the threads 110 is much less than the length of the washer shown in fig. 1.

However, as described below, another function defines a potential reduction in the stroke length 112 of the actuator piston 123.

In this commercial product, the alpha lubrication system is improved compared to the above-mentioned patents DE19743955B4 and DK173288B1 by using a capacitive feedback sensor 120 to verify whether the stroke length of the hydraulic actuator is sufficiently long.

The feedback sensor 120 is also shown in fig. 1. As shown, the hydraulic actuator piston includes two circumferential grooves 111, and if the stroke of the hydraulic actuator piston 123 is long enough to allow the second groove 111 to move past the feedback sensor 120, the feedback sensor 120 signals a confirmation to the central controller that the lubrication is correct. When the first and second grooves 111 pass the feedback sensor 120, the feedback sensor 120 generates a double pulse signal, which the central controller uses as a confirmation signal that the lubrication is correct. If only one first groove 111 passes the feedback sensor 120, a corresponding single pulse signal from the feedback sensor 120 indicates to the central controller that the general function of the feedback sensor 120 and the actuator piston 123 have moved at least a short distance, but that the movement of the actuator piston 123 is insufficient to achieve proper lubrication. If any signal is given by the feedback sensor 120, a warning message is provided by the controller that the measured stroke is not long enough for proper lubrication.

Although the front end stop 105 of the hydraulic actuator piston 123 is adjustable by means of the adjusting screw 121 and can be further adjusted by means of the washer 122, the minimum stroke length of the hydraulic actuator piston 123 must still be long enough to enable the second groove 111 to move past the feedback sensor 120, since otherwise this would lead to the controller registering an insufficient lubrication.

The amount of alpha oiler injected is determined by the frequency of injection into the engine. In actual operation, the injection of the lubricating oil by the alpha oiler is not performed for each revolution of the engine, but is generally performed only for each fixed number of revolutions, for example, once per 10 or 12 revolutions of the engine.

In some research projects, there is evidence that more frequent oil injections may result in better lubrication of marine engines and reduced wear of engine cylinders than 10 or 12 revolutions of the engine. Higher injection frequency requires lower doses per injection, so as not to increase the overall consumption of lubricating oil. The reference is the 283 st paper "Lubtronic SIP premium demarkat low wind rates with low CLO control" published by Yansen et al on CIMAC congress, Finland, on 6.6-10 months 2016.

However, when considering the possibility of changing the alpha system to more frequent lubrication, this means a difficulty in that, as described above, the stroke length of actuator piston 123 cannot be reduced to less than the minimum stroke length determined by feedback sensor 120 in combination with groove 111 in actuator piston 123 in alpha lubricator 100. The minimum stroke length determined by the feedback sensor 120 is difficult to reduce because the signal is provided by the fixed groove 111 in the metal actuator piston 123. Thus, this change to change alpha lubricator 100 to higher frequency lubrication is a complex task.

This problem is widespread and, as far as the oiler is particularly suitable as a SIP injection, is also applicable to the improvement of the alpha system.

In this respect, it is proposed that the market demand for SIP injection systems is increasing, due to their advantage of correct lubrication at low oil consumption. However, in some cases, there is a requirement that the entire lubrication system of the engine not be replaced, but only the part that has to be replaced to achieve the desired effect. This is not only a cost issue but also a benefit based on retaining those modules in the system that appear to function well. In particular, it is generally required to change the dense jet injection to the SIP injection with the lubricating oil mist.

In the case where an alpha lubricator is used as the dense jet injection and the SIP injector is installed as a substitute for the dense jet injector, further modification is required because the SIP injector requires a higher injection frequency than the dense jet injection using the alpha lubricator. For example, a SIP injection may be performed once or even more than once per revolution. However, as mentioned above, such an upgrade seems to be a significant task due to the feedback sensors.

Therefore, the correct upgrade step needs to be found.

Disclosure of Invention

The present invention aims to provide improvements in the art. A particular object is to provide a method of upgrading a lubrication system, in particular an alpha lubrication system, in a large low speed two stroke engine. It is also an object to provide a lubrication system suitable for SIP injection. This object is achieved by a method of improving the lubrication of a large low speed engine. It is specifically achieved by a method of improving a lubrication system described in more detail below.

The lubrication system provides lubricant to the injector for lubricating a cylinder or cylinders in a large low speed two-stroke engine, such as a marine engine or a large engine in a power plant. Typically, the engine combusts diesel or gaseous fuel. The engine includes one or more cylinders, each cylinder having a reciprocating piston therein and a plurality of injectors distributed along the circumference of the cylinder for injecting lubricant into the cylinder at different locations along the circumference during an injection phase.

The lubrication system includes a lubricator with a lubricator conduit connected to each injector by a lubricant supply conduit to provide pressurized lubricant to each injector through the lubricant supply conduit during an injection phase.

The lubricator is of the type having a hydraulically driven actuator piston disposed in a housing for reciprocation in a stroke direction over a stroke length. The lubricator also includes a stroke length adjustment mechanism configured to variably adjust a stroke length of the reciprocating hydraulically driven actuator piston between a minimum stroke length and a maximum stroke length.

The lubricator also includes a plurality of spray plungers slidably disposed in respective dosing passages, wherein the spray plungers are coupled to the actuator piston so as to be moved by the actuator piston and pressurize lubricant in the dosing passages during the movement. When the actuator piston moves over the entire stroke length, the injection plunger also moves a corresponding length. The movement of the injection plunger in the dosing channel pressurizes the lubricant in the dosing channel while the injection plunger moves the dosing channel distance, wherein the dosing channel distance defines the amount of lubricant that is discharged from the dosing channel via the one-way valve and via the supply conduit to the injector during an injection phase for injecting the lubricant into the engine cylinder.

As will be apparent below, the ingredient passage distance is equal to or less than the stroke length. Depending on the structure also discussed above.

The dosing channel distance is adjustable between a minimum dosing channel distance and a maximum dosing channel distance, which corresponds to a variable stroke length of the actuator piston between a minimum stroke length and a maximum stroke length. By reducing the stroke length of the actuator piston, the dosing channel distance is also reduced and the amount of lubricant discharged is correspondingly reduced.

The oil injector further includes an electrically operated valve provided for shifting a hydraulic pressure level acting on the actuator piston, thereby hydraulically driving the actuator piston reciprocally by shifting the pressure level. Normally the actuator piston is prestressed against the rear end stop by a helical spring.

In particular embodiments, the oil injector receives high pressure oil to drive the actuator piston, and the electrically operated valve switches between the following two settings

a) During the injection phase, pressure oil may enter the actuator piston;

b) during the injection phase gap, the actuator piston and the drain tube are connected so that oil drains away from the actuator piston.

The lubrication system further comprises a controller electrically connected to the electric valve for controlling the timing of the switching of the injection phases by means of respective electric signals transmitted from the controller to the electric valve.

In accordance with the above objects, a lubrication system is improved after a certain period of normal engine operation.

In more detail, the method comprises

-operating the engine lubricated by the lubricator, under the control of the controller, to inject a first number of revolutions of the engine through the lubricant injector;

-stopping the engine to improve the lubrication system;

-improving the lubrication system;

-continuing to operate the engine with the improved lubrication system.

The modification to the lubrication system includes modifying the lubricator by reducing the dosing passageway distance to less than the minimum dosing passageway distance and operating the engine at a reduced dosing passageway distance and a corresponding reduced amount of lubricant displaced from the dosing passageway during each injection phase. In particular, it is possible to use, for example,

further, the improvement comprises operating the engine lubricated by the improved lubricator at a higher injection frequency with one injection per second number of revolutions, wherein the second number is less than the first number. And

from the above, the escalation results in an increase in injection frequency and a decrease in the amount of lubricant per injection. The increased injection frequency improves lubrication and reduces wear of the engine. The reference is a 283-paper "Lubtronic SIP premium demarkat low wind rates with low CLO control", published by CiMAC at Finland, 6-10, 6.2016, Yansen et al. SIP spraying is also referred TO as "spray INJECTION spraying-A New TECHNOLOGY TO OBTAIN LOW CYLINDER OIL CONSUMPTION WITHOUT SACRIFICING WEAR RATES" published by Laolisson et al 2001 at the Hamburg CIMAC congress.

Advantageously, in continued operation of the engine using the modified lubricator, the total lubricant consumption is less than or equal to the lubricant consumption prior to modification of the lubrication system. Since the higher injection frequency does not conflict with the objective of minimizing fuel consumption, the overall result is a better lubrication without increasing the fuel consumption in terms of the environment.

In some embodiments, particularly for alpha injectors, the housing includes an interior volume for containing lubricant, and the dosing passage includes an inlet aperture in communication with the interior volume to receive lubricant from the interior volume when the injection plunger is in the retracted position. The inlet aperture has an aperture width between an aperture trailing edge and an aperture leading edge and is arranged such that after passing the aperture leading edge during movement of the injection plunger, the inlet aperture is closed by the injection plunger such that further movement of the injection plunger along a dosing channel distance from the aperture leading edge to a most forward position of the injection plunger pressurizes and discharges lubricant contained in the dosing channel through the one-way valve.

One option for the improvement of these embodiments is to reduce the ingredient passage distance, including increasing the width of the inlet aperture in the forward direction. In this case, the injector plunger is retarded in its movement past the orifice leading edge of the inlet orifice during the stroke of the actuator piston, so that the remainder of the dosing passage, i.e. the dosing passage distance, is shortened, and the lubricant is pressurized and discharged in the dosing passage distance.

Another alternative is to provide another inlet passage closer to the most forward position of the injection plunger. So that the lubricant is pressurized and discharged only after the injection plunger has moved through the other inlet channel. This also shortens the distance of the dosing channel where the lubricant is pressurized and discharged.

Alternatively, or additionally, the modification of the lubrication system includes modifying the lubricator by altering the stroke length to be less than the original minimum stroke length; and operating the engine lubricated by the modified lubricator at a higher injection frequency, wherein the modified lubricator has a modified stroke length less than the original minimum stroke length, the higher injection frequency being one injection per second number of revolutions, wherein the second number is less than the first number.

In some embodiments, in particular as discussed above with respect to the alpha lubricator, prior to improving the lubrication system, the lubricator comprises a feedback sensor configured to measure the stroke at least when the stroke reaches a predetermined minimum displacement of the actuator piston moving during the injection phase, and to issue a feedback signal when the minimum displacement is measured. The controller is configured to receive the feedback signal as confirmation of proper lubrication.

Optionally, the actuator piston is provided with a groove which moves past a feedback sensor during the movement of the actuator piston if the stroke length reaches at least a predetermined minimum displacement, the latter ensuring correct lubrication injection. As mentioned above, reducing the stroke length below the predetermined minimum displacement presents the problem of: the improvement in this case leads to a lack of correct feedback signals.

Since the feedback sensor is an indicator that the lubrication system is functioning properly before improvement and the sensor reading correctly is associated with the mechanical part of the actuator piston, a particular improvement is required because it is not appropriate for the controller to issue a continuous error or warning signal.

This problem can be solved by feeding a corresponding signal from the electronic signal simulator to the central controller. In this case, the lack of a signal from the feedback sensor to the central controller is replaced by an analog signal from the electronic signal simulator, so that the central controller receives a signal from the simulator indicating proper lubrication.

More specifically, the improvement in the lubrication system comprises: providing a feedback signal simulator separate from the feedback sensor, electrically decoupling the feedback sensor from the controller, and providing a simulated feedback signal from the feedback signal simulator to the controller to simulate proper lubrication to the controller despite the actuator piston operating with an improved stroke length less than the minimum stroke length and less than the predetermined minimum displacement.

Possibly, the function of the central controller checking the signal from the feedback sensor or simulator is decoupled from the function of the central controller adjusting the total lubricant amount. Thus, even if the central controller receives a signal from the simulator indicating a sufficient stroke length, the stroke length itself can be reduced to less than the predetermined minimum displacement, and the central controller will not recognize it as a system fault.

In some embodiments, the feedback sensor is arranged to provide a feedback signal having a first type of feedback signal, for example a feedback signal having a single pulse, when the feedback sensor senses that the actuator piston is moving from its position in an idle phase between injection phases, and wherein the feedback sensor provides a second type of feedback signal, for example a feedback signal having a double pulse, only when the actuator piston reaches a predetermined minimum displacement during an injection phase. For this embodiment, the lubrication system is advantageously modified such that upon receipt of the first type of signal from the feedback sensor, the feedback signal simulator provides a simulated second type of feedback signal to the controller as it is indicative of movement of the actuator piston. However, if no signal is received from the feedback sensor, no signal is sent to the controller, which will cause the controller to provide an alarm. On the other hand, if the stroke length of the actuator piston is sufficient to cause the feedback sensor to provide a second type of signal, the simulator will also send the second type of signal to the controller.

Optionally, the feedback signal simulator is equipped with an LED to ensure the feedback signal sensor is in a normal working state by visual inspection.

Decoupling between the amount of lubricant injected and the signal from the feedback sensor facilitates the central controller adjusting to inject at a higher injection frequency and less lubricant per injection.

Some practical ways of reducing the stroke length are outlined below.

In some embodiments, the stroke of the actuator piston is defined by a front end stop and a rear end stop, wherein the position of the front end stop or the rear end stop is defined by an adjustment mechanism that is adjustable between a minimum position and a maximum position, wherein the minimum position defines a minimum stroke length and the maximum position defines a maximum stroke length. The lubrication system is improved by varying the minimum position to an improved minimum position which defines an improved minimum stroke length. For example, the modified minimum stroke length is shorter than the predetermined minimum displacement.

For example, the position of the front end stop is defined by one end of a stroke length adjustment screw, which can be adjusted along the stroke length by rotating the stroke length adjustment screw. One method of modifying the lubrication system includes replacing the stroke length adjustment screw with a longer modified adjustment screw. Alternatively, material may be added to the stroke length adjustment screw in the space between the stroke length adjustment screw and the actuator piston, effectively lengthening the screw and reducing the stroke length.

In some embodiments, the oil injector includes a flange provided with a screw bearing for supporting the stroke length adjustment screw. One method of improving the lubrication system includes replacing the flange or removing material from the flange by machining the flange.

By reducing the length of the flange measured in a direction parallel to the stroke direction of the actuator piston, the screw bearing moves towards the actuator piston, causing the front end stop defined by the stroke length adjustment screw to move towards the actuator piston, which changes the minimum position.

In the case of an adjusting screw which can be adjusted by rotating in a thread in the flange, a possible modification of the flange means that the flange is machined in such a way that the length of the thread increases in the direction of the actuator piston, thereby increasing the adjustment length of the adjusting screw. By rotating the adjusting screw over a greater length, the stroke length of the actuator piston is reduced.

For example, a motor is mounted to the end of the screw for rotating the screw. The latter allows an electrical adjustment of the position of the adjusting screw and thus of the stroke length. This allows the adjustment screw to be rotated by the motor in the jet gap to change the stroke length. For example, the motor is controlled by an upgraded controller, enabling programming and electrical adjustment of the actuator piston.

In summary, adjusting to more frequent injections requires the following adjustments:

1) reducing the amount of lubricant per spray

2) Increasing injection frequency

3) It is possible to simulate the signal from the feedback sensor and feed this simulated signal into the central controller.

If the feed rate data in the central control cannot be set to a specific correction distance to the front end stop, the actually required feed rate F can be compensated for_desiredAnd dividing it by the ratio R of the modified actual stroke length to the original stroke length before modification, to adjust the feed rate to the correct value. The stroke length adjusted in the central control will therefore be F_controller＝F_desired/R。

Note that for reduced stroke lengths, R is less than 1. For example, if the stroke length is reduced from 12mm to 6mm, the ratio R is 6/12-0.5, and the central control must be adjusted to double the feed rate compared to the standard case without the modified lubricator. For example, a double feed rate can be achieved by doubling the injection frequency.

Under special conditions, reducing the stroke length by the above method requires further consideration. For example, if a cylinder liner or piston in an engine cylinder has been replaced, a higher lubricant feed rate may be required than would be possible for a shortened stroke length. Optionally a higher supply is achieved with a higher lubrication frequency. Alternatively, the stroke length is increased for a limited period of time, for example by inserting a gasket between the flange and the rest of the housing to increase the distance to the front end stop.

The stop piece is arranged atThe fact that the feed rate data is adjusted in the central controller before and after a limited period of time, either before and after a back and forth movement, or as mentioned above, after the central controller is adjusted to a specific feed rate F_control＝F_desiredThe equivalent feed rate is established in the case of/R. This expression is valid for washers that are inserted for a limited period of time, even if the washer expands the stroke length to be greater than the original maximum. The overall effect is that the feed rate in the central controller can be adjusted to a value different from the actual injection quantity, which difference results from the ratio of the corrected stroke length to the original stroke length.

Optionally, an upgraded controller is electrically connected between the central controller and the lubricator for adjustment of the feed rate and frequency. The upgraded controller is advantageously provided as an additional unit. Which receives control signals from a central control, including timing signals for the correct timing of the injection by the lubricator and possibly signals for adjusting the stroke length by means of an adjusting screw. Based on the signal received from the central controller, the upgraded controller sends a modified timing signal and a modified stroke adjustment signal to the lubricator. Since the upgraded controller is programmed for the modified stroke length, the signal from the central controller is converted to a modified signal as necessary to provide the correct timing, frequency and stroke length of the lubricator.

Possibly, the upgraded controller further comprises the above mentioned simulator for simulating the feedback sensor signal and sending the simulated feedback sensor signal to the central controller for avoiding that the central controller registers a lack of feedback sensor signal indicating a lack of correct lubrication.

For the sake of clarity, it is noted that the term "injector" is used for an injection valve system comprising an injector housing having a lubricant inlet port, which is in fluid connection with a lubricant supply conduit to receive lubricant therefrom for injection into the cylinder. The injector further comprises a separate injection nozzle with a nozzle hole as lubricant outlet, which nozzle extends into the cylinder for injecting lubricant from the inlet into the cylinder during an injection phase. Although the injector has only one nozzle extending through the cylinder wall into the cylinder, the nozzle itself may alternatively have more than one hole when the injector is properly installed. For example, a nozzle with a plurality of orifices is disclosed in WO 2012/126480.

The term "injection phase" is used for the time during which the injector injects lubricant into the cylinder. The term "idle period" is used for the time between injection periods. The term "injection cycle" is used for the time it takes to start an injection sequence until the start of the next injection sequence. For example, the injection sequence includes a single injection, in which case the injection cycle is from the beginning of the injection phase to the beginning of the next injection phase. The term "timing" of injection is used to adjust the start of an injection phase of an injector relative to a specific position of a piston in a cylinder. The term "frequency" of injection is used for the number of injector injections that are repeated per engine revolution. If the frequency is 1, there is one injection per revolution. If the frequency is 1/2, there is one injection for every two revolutions. This term is consistent with the prior art described above.

For example, each injector comprises a discharge valve system at the nozzle, arranged to open to flow lubricant to the nozzle holes during an injection phase when the pressure at the discharge valve system rises above a predetermined threshold, and to close the discharge valve system after the injection phase. The exhaust valve system closes to prevent back pressure from the air cylinder and to prevent lubricant from entering the cylinder unless the exhaust valve is open.

For example, the discharge valve system includes a discharge check valve. In a discharge check valve, a discharge valve member, such as a ball, ellipse, plate or cylinder, is pre-stressed against a discharge valve seat by a discharge valve spring. When pressurised lubricant is provided in the fluid chamber upstream of the discharge valve system, the pre-stressing of the spring is counteracted by the lubricant pressure and, if the pressure is higher than the spring force, the discharge valve member is displaced from its discharge valve seat, the discharge non-return valve opens so that lubricant is injected through the nozzle holes into the cylinder. For example, the discharge valve spring acts on the valve member in a direction away from the nozzle bore, although movement in the opposite direction is also possible.

For example, the central controller or the upgraded controller or both comprise a computer or are connected by wire or wirelessly to a computer, wherein the computer is of a type arranged to monitor the actual state and the kinetic parameters of the engine, such that the amount and timing of lubricant injection can be controlled based on these parameters.

Optionally, the injector is a SIP injector arranged to provide a lubricant mist into the purge air of the cylinder. Atomized droplet spray, also known as oil mist, is important in SIP lubrication where a spray of lubricant is repeatedly injected by the injector into the cylinder's purge air before the piston moves through the injector toward TDC. In the purge air, the atomized droplets are transported in a direction toward TDC, spread and distributed on the cylinder wall due to the swirling motion of the purge air toward TDC.

An example of such an injector for SIP injection is disclosed in WO 2012/126473. Other possibilities of SIP injectors provided with an electric valve are found in danish patent applications DK201770936 and DK 201770940.

For example, the ejector comprises a nozzle provided with a nozzle aperture of between 0.1-1mm, for example between 0.2-0.5mm, and arranged to eject an atomized droplet spray, also referred to as an oil mist.

Atomization of the spray is due to the high pressure lubricant at the nozzle in the lubricant injector. The pressure is higher than 10 bar, usually between 20 and 120 bar, for this high pressure injection. An example is an interval between 30 and 80 bar, optionally between 35 and 60 bar. The injection time is very short, typically about 5-30 milliseconds (msec). However, the injection time can be adjusted to 1 millisecond, or even less than 1 millisecond, for example as low as 0.1 millisecond.

In addition, viscosity affects atomization. The viscosity, typically kinematic viscosity, of lubricants used in marine engines is about 220cSt at 40 ℃ and about 20cSt at 100 ℃, which translates to a dynamic viscosity between 202 and 37mPa · s. An example of a useful lubricant is high performance marine diesel cylinder oilMobilgard^TM560 VS. Other lubricants that may be used in marine engines are other Mobilgard^TMOil andcyltech oil. Common lubricants for marine engines have approximately the same viscosity curve in the range of 40-100 c and are all available for atomization, for example when the nozzle hole diameter is 0.1-0.8mm and the lubricant pressure at the nozzle hole is 30-80 bar and the temperature is in the range of 30-100 c or 40-100 c. See also the article on this subject published by rathsanravendan, Peter Jensen, Jesper de Claville Christiansen, Benny endlt, Erik Appel Jensen, (2017) "rheological behaviour of two-stroke marine lubricant oil", "industrial lubrication and tribology", volume 69, No. 5, page number: 750 ion 753, https:// doi. org/10.1108/ILT-03-20l 6-0075.

Drawings

The invention will be further explained with reference to the drawings, in which

FIG. 1 is a reproduction of a depiction of the alpha controller published on the website http:// www.mariness.co.kr/02_ business/Doosan% 20 Retrofit% 20Seivice pdfPHPSESSIP ═ fd56da9de6eaca2f1f446512e84fcf 69;

FIG. 2 is a diagrammatic view of a portion of a cylinder in an engine.

FIG. 3a) shows an example of the oil squirt before modification, b) shows an enlarged view of a portion of the oil squirt around the inlet hole, and c) shows the portion of the oil squirt of FIG. 3b) after modification of the inlet hole to a larger width.

Figure 4 shows an inlet hole modified with respect to figure 3a to provide a new, closer one-way valve for discharging lubricant.

FIG. 5 shows an example of the oil lubricator with the length of the adjusting screw added after the modification.

Fig. 6a) shows an example of a grease filler in which the gasket shown in fig. 3a has been removed and the flange of the grease filler has been modified by machining.

FIG. 7 illustrates another embodiment wherein the upgraded controller is electrically connected between the controller and the lubricator.

Detailed Description

Fig. 1 is a reproduction of a depiction of the alpha controller published on the website http:// www.mariness.co.kr/02_ business/dosan% 20 Retrofit% 20 service pdfppsesssip ═ fd56da9de6eaca2f1f446512e84fcf 69.

This mapping of an alpha grease is taken as an example of a specific embodiment of an improved grease squirt, as in the method described herein. The statements given in the introduction therefore also apply to the statements on the modifications.

Fig. 2 shows half of a cylinder of a large low-speed two-stroke engine, for example a marine diesel engine. The cylinder 1 comprises a cylinder liner 2 located inside a cylinder wall 3. A plurality of injectors 4 are provided in the cylinder wall 3 for injecting lubricant into the cylinder 1.

As shown, the injectors 4 are distributed along a circle with the same angular distance between each two adjacent injectors 4, although this is not strictly necessary. Furthermore, a circled arrangement is not necessary, as an arrangement with axial displacement of the injectors is also possible, e.g. every other injector is moved towards the Top Dead Centre (TDC) of the piston relative to the adjacent injector.

As shown, injector 4 receives pressurized lubrication oil from an oil injector 11 via a lubrication supply line 9. The supplied lubricating oil is typically heated to a specific temperature, for example 50-60 degrees celsius. The oil injector 11 supplies pressurised lubricating oil to the injector 4 in precisely timed pulses synchronized with the piston movement in the cylinder 1 of the engine. The controller 12 controls the injection of the lubricator 11. For synchronization, the controller 12 monitors the actual state of the engine and the parameters of the motion, such as speed, load, and crankshaft position, the latter of which reveals the piston position in the cylinder.

Each injector 4 comprises a nozzle 5, which nozzle 5 is provided with a nozzle aperture 5 ', from which nozzle aperture 5' lubricant is injected into the cylinder 1 under high pressure, for example in the form of a dense jet or in the form of a fine atomized spray 8 with small droplets 7 for SIP injection.

For example for SIP spraying the nozzle orifice, which atomizes the lubricant into a fine spray 8, as opposed to a dense jet of lubricant, has a diameter of between 0.1 and 0.8mm, for example between 0.2 and 0.5mm, and a pressure of between 10 and 120 bar, for example between 20 and 100 bar or between 20 and 120 bar, optionally between 30 and 80 bar or even between 50 and 80 bar, or even at a pressure higher than 120 bar. The swirl 10 of the purge air in the cylinder 1 transports and presses the spray 8 against the cylinder liner 2, thereby achieving an even distribution of the lubricating oil over the cylinder liner 2.

Optionally, the cylinder liner 2 is provided with a free cut 6 for providing sufficient space for the spray 8 or jet from the injector 4.

The lubricator 11 is connected to a supply conduit 14 for receiving lubricant from a lubricant supply 15, including an oil pump, and to a return conduit 13 for return of lubricant, typically to a sump, optionally for recirculation of lubricant. The lubricant pressure in the supply conduit 14 is higher than the pressure in the return conduit 13, for example at least twice as high. The lubricant supply conduit 14 is also used for supplying lubricant, in addition to driving the actuator piston, for lubrication.

Fig. 3a shows an example of the lubricator 11 before modification. The same reference numerals are used for the improved prior art lubricator of fig. 1.

Fig. 3b shows an enlarged view of the portion of the lubricator 11 around the inlet aperture 113 of the dosing channel 115 with the injection plunger 119. The inlet aperture 113 includes a leading aperture edge 113a and a trailing aperture edge 113b that collectively define the width of the aperture 113.

FIG. 3c shows the grease injector portion of FIG. 3b after modification of the inlet aperture to a greater width, as best seen by the increased spacing between the aperture leading edge 113a and the aperture trailing edge 113 b.

Fig. 4 shows a modification of fig. 3a and 3b, whereby the distance of the dosing passageway is shortened compared to the distance of the lubricator 11 before modification by providing a new inlet aperture 113 ' closer to the front end of the dosing passageway 115 with a corresponding new leading edge 113a ' and trailing edge 113b '.

Fig. 5 shows an example of the lubricator 11 in which the adjusting screw 121 is made longer after modification. In this example, the adjusting screw 121 is provided to have a longer middle portion 121A. A longer adjustment screw reduces the stroke length 112 of the actuator piston 123.

FIG. 6 shows an example of the modified lubricator 11, wherein the modification consists in removing the gasket as shown in FIG. 3a and modifying the grease flange by machining, increasing the length of the thread 110 so that the adjusting screw 121 can move closer to the actuator piston 123, which shortens the stroke length 112.

Variable adjustment of the stroke length by the adjustment screw 121 may be accomplished by rotating the adjustment screw 121 using a motor, such as a DC motor, mounted on the end cap of the lubricator and controlled by an upgraded controller 19. This enables electronic adjustment of the stroke length, for example by means of an upgraded controller 16. This makes it possible to adjust the stroke length in the injection gap, for example in dependence on the operating parameters of the engine.

FIG. 7 shows another embodiment in which an upgraded controller 16 is electrically connected between the controller 12 and the lubricator 11.

The upgraded controller 16 is used to adjust the feed rate and frequency. Which receives control signals from controller 12 including timing signals for the precise timing of the injection by injector 11 and possibly stroke length adjustment by an adjustment screw. Based on the signals received from the controller 12, the upgraded controller 11 sends a modified timing signal and a modified stroke adjustment signal to the lubricator 11. Since the upgraded controller 16 is programmed for the modified stroke length, the signal from the controller 12 is converted to a modified signal as necessary to provide the correct timing, frequency and stroke length of the lubricator 11.

For the case where the lubricator 11 includes a feedback sensor 120, as shown in fig. 1 and 3a, the upgraded controller 16 further includes a signal simulator for simulating the feedback sensor signal and sending the simulated feedback sensor signal to the controller 12 for use by the controller 12 to avoid registering a lack of feedback sensor signal indicating a lack of proper lubrication.

Referring to fig. 3a, it can be seen that the actuator piston 123 comprises two grooves 111A, 111. When the actuator piston moves, the first groove 111A will cause the feedback sensor 120 to give a first pulse in the feedback signal. Another pulse in the feedback signal can only be generated if the stroke 112 is long enough to allow the second groove 111 to also move past the feedback sensor. In prior art systems, if stroke 112 is long enough to allow both channels 111A and 111 to move past feedback sensor 120, controller 12 would receive a double pulse in the feedback signal from feedback sensor 120. Only if the feedback signal has double pulses will the prior art controller 12 read it as indicating correct lubrication. As mentioned in the above example, the reduction in stroke length in the improved lubrication system results in the feedback sensor 120 giving only a single pulse. The upgraded controller 16 receives this single pulse and recognizes that the actuator piston 123 has moved for injection and accepts it as a signal for proper lubrication. To simulate the correct signal to the original controller 12, the simulator in the upgraded controller 16 generates an analog double pulse signal and transmits it to the controller 12 to avoid the controller 12 issuing an alarm due to the stroke 112 being shorter than the controller's tolerance.

Thus, an upgraded controller has the ability to receive the following possible feedback signals:

1) only a single pulse-indicating that the actuator piston 123 has moved but moved shorter than the stroke length of the un-upgraded lubrication system-the upgraded controller 16 sends an analog double pulse signal to the controller 12 to simulate to the controller 12 that correct lubrication has taken place;

2) double pulse-indicating that the actuator piston 123 has moved and at least moved the stroke length of the un-upgraded lubrication system-the upgraded controller 16 sends an analog double pulse signal to the controller 12 to simulate to the controller 12 that proper lubrication has taken place;

3) an upgraded controller that does not receive a pulse-indicating that the actuator piston is not moving or that the feedback sensor is malfunctioning-will not send an analog signal to the controller, thereby causing an alarm condition. The latter may optionally be further supported by the upgraded controller itself issuing an alert signal in such a case. Such a warning signal may be a visual signal and/or an audible signal. Such as flashing lights, monitoring a computer interface for warning messages, and warning sounds.

The above-mentioned patent applications relating to SIP injectors are incorporated by reference into the present application.