KR20120112620A - Purging method and system with scraper or wiper ring for preventing formation of deposits inside fuel pump - Google Patents

Abstract

The present invention relates to a fuel injection system 100 configured to supply fuel such as, for example, heavy oil to the injection nozzle 105 of a large internal combustion engine 5. The system is configured to measure fuel, for example heavy oil, in the correct amount for injection, accumulating high pressure and delivering it to at least one injection nozzle 110 of the large internal combustion engine 5 at a suitable time. It may include a pump 110. The fuel injection pump 110 extends along the longitudinal direction and is configured to reciprocate in the pump barrel 10 and the pump barrel 10 having the barrel wall 12 and guided by the barrel wall 12. It may include. At least one scraper ring 210; 220 may be attached to one of the plunger 13 and the barrel inner wall 12 and configured to slide along the other of the plunger 13 and the barrel inner wall 12.

Description

Purging method and system having a scraper or a wiper ring to prevent the formation of sediment inside the fuel pump TECHNICAL FIELD

The present invention generally relates to fuel injection systems for supplying fuel, such as, for example, heavy oil, to the injection nozzles of large internal combustion engines. Moreover, the present invention relates to a fuel injection pump as well as a method for purging a fuel injection pump configured to pump fuel, such as heavy oil, for example in large internal combustion engines.

In addition, the present invention purges a high pressure fuel pump for supplying fuel such as heavy oil to the common rail of a fuel injection system, and a fuel pump configured to pump fuel such as heavy oil of a large internal combustion engine, for example. It relates to a method for doing so.

In general, the term “large internal combustion engine” refers to internal combustion which can be used as the main or auxiliary engine of a ship / ship such as cruiser liner, cargo ship, container ship and tanker or in a power plant for the generation of heat and / or electricity. It can be called an organ. In particular, the large internal combustion engine may be configured to burn at least one fuel selected from the group consisting of diesel, marine diesel oil (MDO) and heavy oil (HFO).

The terms "fuel injection pump" and "high pressure fuel pump", as used herein, may be substituted for one another. In other words, the presented characteristics of the fuel injection pump according to the invention may also be provided for a high pressure fuel pump that can be used to supply fuel such as heavy oil or the like to the common rail at high pressure.

Heavy oil may contain "asphaltene". Asphaltenes can be defined as molecular substances found in crude oil together with resins, aromatic hydrocarbons and alkanes (ie saturated hydrocarbons). Asphaltene may consist primarily of carbon, hydrogen, nitrogen, oxygen and sulfur, as well as large amounts of vanadium and nickel. Heavy oils may contain much higher proportions of asphaltenes than intermediate API graphic oils or light crude oils. For example, the ISO 8217 fuel standard may describe various parameters of "heavy oil", also referred to as "ship distillate oil" or "ship residual oil."

In addition, fuels such as diesel or MDO may contain contaminants such as for example heavy oil and / or other components such as for example zinc. These contaminants can produce precipitates in the pump. In the case of zinc, a layer of zinc sulfate may develop.

Fuel injection pumps are basically known for supplying fuel, such as heavy oil, to the injection nozzles of large internal combustion engines. These pumps are configured to measure fuels such as heavy oil with the correct amount of oil injection, thus accumulating high pressure and delivering them to the injection furnaces of large internal combustion engines in a timely manner. Such a fuel injection pump may comprise a pump housing, a pump barrel arranged in the pump housing, the pump barrel extending along the longitudinal direction and having a barrel inner wall. The plunger is configured to reciprocate in the pump barrel and can be guided by the barrel inner wall. A first groove may be formed in the barrel inner wall at the first position relative to the longitudinal direction and covered by the plunger.

Fuel injection pumps of the type described above are known, for example, from GB 2 260 374 A. It is known in this document to provide a groove in the wall of the bore that is connected to the supply of lubricant under pressure, the groove being arranged at the end of the bore from which the plunger extends and in the middle of the port or port. Since the plunger reciprocates, the lubricant is withdrawn from the groove to provide lubrication of the working clearance between the plunger and the wall of the bore. Some lubricant will flow out of the working gap and lubricate the working surface. However, fuel due to the high fuel pressure developed in the pumping chamber of the pump will also flow along the working gap and will mix with the lubricant in the groove and flow onto the working surface. If the fuel is diesel, such as used in automotive diesel engines, the leakage of fuel is not serious until now. When lubrication of various surfaces is involved, it is desirable that the leakage of fuel is as small as possible because it eliminates engine lubricant. To this end, it is known to provide an additional groove and the aforementioned groove in the middle of the port and the ports and to connect the additional groove to the low pressure fuel source so that the mature fuel is collected and returned to the source.

It is also mentioned that the leakage of fuel as described presents a number of problems if the fuel is, for example, heavy oil (eg HFO) of the type required to be heated before being supplied to the pump. First, the fuel will tend to accumulate in the grooves and the lubrication as described may be impaired. Second, since heavy oils block the intended flow of lubricants, lubricants tend to form lockers due to heat. Third, the fuel oil tends to solidify when the engine is stopped, making it difficult unless the means for controlling the setting of the sleeve is functional.

In the aforementioned GB 2 260 374 A it is disclosed to provide a circumferential groove in the wall of the bore in the middle of the port or ports and at the end of the bore from which the plunger extends. A first passage is formed in the pump barrel, which in use is connected to the source of lubricant under pressure, the second passage in the pump barrel is connected to the groove and a controlled flow of lubricant occurs therethrough in the use of the pump. Thus, deposits that may accumulate in the pump barrel can be removed by pumping diesel fuel instead of heavy oil with this fuel injection pump for a certain period of time. Therefore, purge cannot be performed without stopping the normal heavy oil supply.

EP 0 537 911 B1 mentions a very similar fuel injection pump. EP 0 537 911 B1 is a common practice when stopping the engine to purge a heavy oil pump by operating it for a period of time on light oil by means of a pump known from GB 2 260 374 A. This avoids the possibility of heavy oil solidification in the various passages in the pump, thereby preventing or hindering the engine restart without heating the pump, but it will be necessary to provide lubrication of the plunger when switching to diesel by such a pump. . As a solution, EP 0 537 911 B1 discloses the provision of a pair of switching valves for controlling liquid flow into and out of each of the passages and grooves interconnecting the first and second grooves. The first of the valves connects the associated groove to the drain when in one position and connects the associated groove to a kind of lubricating oil under pressure in the other position when heavy oil is pumped by the pump; The second of these valves connects the associated groove to the drain when in one position and connects the associated groove to the lubricant drain in that position when heavy oil is pumped by the pump. The changeover valve is in these positions when the diesel oil is pumped by the pump. Lubricant flows between the grooves through the passageway. Therefore, the fuel injection pump known from EP 0 537 911 B1 may exhibit the same problem as the fuel injection pump of GB 2 260 374 A.

Current hard coatings can often be used on pump plungers as a means for wear and seizure of the plunger. These layers can have very low surface roughness. Such a coating may generally not be used inside the barrel, so the layers will appear mainly on the barrel surface due to their higher surface roughness, which is a better junction for the sediment layer.

The present invention is directed to at least partially improving or overcoming one or more aspects of conventional systems.

In a first aspect of the invention, a fuel injection system configured to supply fuel, such as, for example, heavy oil to the injection nozzles of a large internal combustion engine, can be configured to measure fuel, such as, for example, heavy oil, in an accurate amount for injection. And a fuel injection pump that can be configured to accumulate high pressure and deliver it to at least one injection nozzle of a large internal combustion engine at a suitable time. The fuel injection pump may include a pump barrel extending along the longitudinal direction and having a barrel wall, and a plunger configured to reciprocate in the pump barrel and guided by the barrel wall. At least one scraper or wiper ring may be attached to one of the plunger and barrel inner wall and may be configured to slide along the other of the plunger and barrel inner wall.

In another aspect of the invention, the fuel injection pump may be configured for use in a fuel injection system of the type described above. The fuel injection pump may be configured to measure fuel, such as heavy oil, for example, in an accurate amount for injection, accumulating high pressure and delivering it to at least one of the injection nozzles of a large internal combustion engine at a suitable time. The fuel injection pump may comprise a pump barrel extending along the longitudinal direction and having a barrel inner wall, and a plunger configured to reciprocate in the pump barrel and be guided by the barrel inner wall. At least one scraper ring may be attached to the plunger and configured to slide along the barrel inner wall.

In another aspect of the invention, the fuel injection system may be configured to supply fuel, such as heavy oil, to the common rail of a large internal combustion engine. The system may include a high pressure fuel pump configured to supply fuel to the common rail at high pressure, for example heavy oil. The fuel pump may include a pump barrel extending along the longitudinal direction and having a barrel wall, and a plunger configured to reciprocate in the pump barrel and guided by the barrel wall. At least one scraper ring may be attached to one of the plunger and barrel inner wall and may be configured to slide along the other of the plunger and barrel inner wall.

In another aspect of the invention, a method for purging a fuel injection pump configured to pump fuel, such as, for example, heavy oil, for example of a large internal combustion engine in a ship or a generator set, may be provided in the barrel inner wall of the fuel injection pump during reciprocating movement of the plunger. Or a method step of mechanically scraping or wiping any precipitate on the plunger. The same method may be applicable to fuel pumps that may be configured to supply fuel, such as heavy oil, to the common rail of large internal combustion engines.

Other features and aspects of the present invention will become apparent from the following detailed description and the accompanying drawings.

1 shows a schematic block diagram of an exemplary embodiment of a fuel injection system of the present invention.
FIG. 2 shows a schematic cross-sectional view of a fuel injection pump that may be configured for use with the fuel injection system shown in FIG. 1.
3 shows a piston and pump barrel configured for use in a fuel injection pump, for example as shown in FIG. 2.
4 shows another schematic longitudinal cross-sectional view of the pump barrel of the fuel injection pump shown in FIGS. 1-3.
4A shows detail “Z1” in FIG. 4.
5 shows an enlarged detail view of the scraper ring or wiper ring mounted to the plunger of the fuel injection pump according to the invention.
6 shows another embodiment of a scraper or wiper ring mounted on a plunger of a fuel injection pump according to the invention.
7 shows another exemplary embodiment of a scraper or wiper ring mounted to a plunger of a fuel injection pump according to the present invention.
8 shows another exemplary embodiment of a scraper or wiper ring mounted on a plunger of a fuel injection pump according to the invention.

1 shows a schematic block diagram of an exemplary embodiment of a fuel injection system 100 configured to supply fuel such as, for example, heavy fuel to the injection nozzle 105 of a large internal combustion engine 5. According to this exemplary embodiment of fuel injection system 100, each injection nozzle 105 may be connected to an associated fuel injection pump 110 via a high pressure fuel line 115. Alternatively, one fuel injection pump 110 may be configured to supply fuel such as, for example, heavy oil to the plurality of fuel injection nozzles 110. Each fuel injection pump 110 may be connected to a fuel reservoir 120 via a fuel supply line 116.

In Figure 1, the basic structure of a fluid injection system according to one aspect of the present invention is shown. Alternative structures may include a common rail and one single fuel pump in place of the plurality of fuel injection pumps 110. Thus, in this alternative structure, the fuel injection nozzle 105 can be connected to the common rail, the high pressure fuel pump can supply fuel to the common rail at high pressure and from the common rail the high pressure fuel is distributed to the individual injection nozzles 105. do.

In the following, further details of the fuel injection pump 110 are provided with reference to FIGS. 2 and 3. Referring to FIG. 2, the pump may include a stepped pump barrel 10 that may be located within the housing 11. A bore in which the reciprocating plunger 13 is formed may be formed in the barrel. The plunger 13 may extend from the end of the barrel 10 and each groove 15 formed in the extension of the control sleeve 16 mounted for angular movement with respect to the cylindrical portion 17 of the barrel 10. It may have a pair of lateral pegs 14 that may be located within. Sleeve 16 may be provided with teeth for engagement by rack bars 18 in a known manner. The plunger 13 may have a foot 19 formed at its free end, which foot 19 is joined by a spring contact 20, which is in turn by one end of the wound compression spring 21. Coupled, the opposite end may additionally be engaged with a flanged spring contact 22 which may function to hold the control sleeve 16 against axial movement.

The housing 11 can form a cylindrical guide surface 23 for a cup-shaped tappet 24 which can be driven inwards by the action of the engine cam directly or indirectly through the rocker mechanism in use. During the inward movement of the tappet 24, its base wall may engage with the foot 19 of the plunger 13 to impart the inward movement of the plunger 13 to the action on the spring. The spring 21 can return the plunger 13 and also the tappet when so allowed by the cam.

In a known manner, a pair of ports 26 may be provided in the walls of the bore in communication with the fuel supply gallery 27 formed between the housing and the pump barrel 10. The port 26 can be arranged to be covered by the plunger 13 after a predetermined inward movement, after which the fuel can be discharged from the pumping chamber 28 partially formed by the end of the plunger and the wall of the bore to the associated engine. will be. The plunger 13 may also have a groove in communication with the pumping chamber 28, the groove having a spiral control edge 29 which may expose one of the ports 26 to the groove after further inward movement of the plunger. With this, fuel can leak from the pumping chamber and return to the supply gallery 27 when the port can be exposed to the groove. The angle setting of the sleeve and plunger can determine the point at which leakage occurs during the inward movement of the plunger and thus the amount of fuel supplied to the associated engine.

A circumferential groove 30 can be formed in the wall of the bore at the end of the barrel 10 where the plunger extends and in the middle of the port 26. The groove 30 may be connected to the gallery 27 such that substantially all fluids that may leak from the pumping chamber due to the high pressure therein when in use of the pump 110 are collected in the groove 30 to allow passage 31. It is possible to return to the fuel supply gallery 27 via).

Depending on the type of fuel pumped in the fuel injection pump 110, for example, a precipitate in the form of a layer of cured asphaltene and / or zinc sulfate and / or zinc sulfite and / or calcium sulfate may, for example, Within the region between 26 and the cylindrical portion 17, it can be deployed on the outer surface of the plunger 13 and / or on the barrel inner wall 12.

Another groove 38 may be formed in the wall of the bore at a position below the groove 30, in particular at a position that may be located further away from the edge 29 than the groove 30 described above. This groove 38 may also be connected to a fuel drain (not shown) via the inlet 33, the passage 32, and the passage 39.

2 and 3, there is shown a more schematic view of a piston 13 and barrel 10 similar to that used for the fuel injection pump 110 shown in FIG. 2, for example. This exemplary embodiment of a modified plunger for fuel injection pump 110 may have a first groove 205 and / or a second groove 215. In at least one of these two grooves 205, 215, the scraper rings 210, 220 may be mounted. The scraper rings 210, 220 may contact the barrel inner wall 12 of the bore at a predetermined pressure to slide along the barrel inner wall 12 during the reciprocating movement of the plunger 13. The scraper ring 210 and / or the scraper ring 220 may prevent the formation of a deposit layer in an area where a deposit layer may generally be created on the barrel inner wall 12. The scraper rings 210, 220 may apply pressure on the barrel inner wall 12 to remove any deposits. The one or more scraper rings 210, 220 may protrude beyond the outer circumference of the plunger 13 by approximately 0.1 to 0.15 mm, for example, if the diameter of the plunger 13 is about 30 mm or less, and the plunger is a barrel 10 Are not inserted into the. In other words, the scraper or wiper ring may have a specific elasticity that allows the rings to be pressed at an appropriate pressure against the barrel inner wall. The same may apply if more than one scraper ring is mounted in a groove formed in the barrel inner wall.

The first groove 215 and the associated scraper ring 220 may be located at a location farther away from the pumping chamber 28 than the first groove 30. Both grooves 215 and associated scraper 220 may be positioned such that scraper 220 may move between first groove 30 and second groove 40 during an alternating movement of plunger 19.

The groove 205 and associated scraper ring 210 may be located at a position in the longitudinal direction of the plunger 13, farther away from the pumping chamber 28 than the groove 215. In addition, the groove 205 and the associated scraper ring 210 have a pumping barrel 10 in which the scraper ring 210 faces the second groove 38 in the barrel inner wall 12 and the foot 13 of the plunger 13. It can be arranged to move in the area between the front end of the.

In this exemplary embodiment of the plunger 13 and the pumping barrel 10 for the fuel injection pump 110, the region of the barrel inner wall 12 between the groove 30 and the groove 38 and the pump 38 with the groove 38. The area between the front ends of the barrel 10 may be scraped or wiped by the scraper rings 210, 220.

4 shows another exemplary embodiment of the plunger 13 and the pumping barrel 10. Only grooves 215 and associated scraper rings 220 may be provided. The pumping barrel 10 of this exemplary embodiment shown in FIG. 4 may include grooves 230 formed in the barrel inner wall 12. The groove 230 may be insertable with the plunger 13 and at the same time may be chamfered to reduce or avoid damage to the scraper ring 220.

FIG. 5 shows a schematic cross-sectional view of the ring 220 mounted in the groove 215 of FIG. 4. Here, the scraper ring 220 may have upper and lower edges with sharp edges, for example. In addition, the scraper ring 220 may have internal elasticity and internal spring force such that the scraper 220 may tend to extend radially outward, thus contacting the barrel inner wall 12 with its own elasticity. There may be a tendency. The scraper ring 220 may not fit correctly in the groove 215 but it may be possible to fit in the longitudinal direction of the piston 13. The scraper ring 220 may be made of any suitable material, in particular a material selected from the group consisting of metals, fiberglass, reinforced plastics, plastics, epoxies and alloys and any mixtures thereof.

A fiber glass type scraper ring is shown in part in FIG. 6. Here, the fiber glass scraper ring 220 'has a shape similar to the scraper ring 220 of FIG. 5, but has a chamfered edge. Other suitable shapes for scraping or wiping deposits on barrel inner wall 12 may be possible.

Another exemplary embodiment of the scraper ring 220 "is shown in Figure 7. Here, the scraper ring 220" may have a shape such as an O-ring. Here, the scraper ring 220 "can be pressed into a groove 215" formed on the outer surface of the piston 13, so that the outer surface of the ring remains in contact with the barrel inner wall 12 due to the elasticity of the ring. do.

A package of rings 220 "may alternatively be used as shown in FIG.

It should be noted that the scraper rings 220, 220 'or 220 "may have slits to facilitate insertion of the ring in the associating groove 215. Alternatively, the scraper rings 220, 220', 220 ″) may include two or more ring segments inserted into the associated grooves 215, 215 ′, 215 ″.

Industrial availability

1 to 8, the basic operation of the illustrated fuel injection pump and how the purge method can be performed will be described. While pumping fuel such as, for example, heavy oil with the fuel injection pump 110, fuel may leak within the gap between the barrel inner wall 12 and the outer surface of the plunger 13. This fuel may result in the formation of deposits on the plunger 13 and / or barrel inner wall 12. This is because heavy oil (HFO) may include calcium, phosphorus, zinc and sulfur. Thus, precipitates or layers, such as calcium sulfate and / or zinc sulfate and / or zinc sulfite, may also be formed. In addition, the high asphaltene content in heavy oil can also produce deposits in the fuel injection pump, in particular on the plunger outer surface or barrel inner wall 12.

If one or more scraper rings 210, 220 may be arranged on the piston 13 or barrel inner wall 12, any deposits or layers that may develop on the plunger 13 and / or barrel inner wall 12. Purge may be achieved due to scraping or wiping of.

As described above, an alternate fuel injection pump 110 or fuel supply pump may be seen in which purge can be accomplished by at least one scraper ring 210, 220 mounted only on the plunger 13 or barrel inner wall 12. Can be provided according to the invention. In this case, deposits or layers on the barrel inner wall 12 may be scraped or wiped by the scraper rings 210 and / or 220 simultaneously with the reciprocating motion of the plunger 13.

At least one scraper ring 210 (220) may be selected from the group consisting of a spring ring, a slit ring, a ring comprising at least two separate ring segments, a piston ring and a spring washer.

While preferred embodiments of the invention have been described herein, improvements and modifications can be embodied without departing from the scope of the following claims. Examples of such modifications and improvements may be disclosed in the above description and / or in the appended claims.

Claims (8)

A fuel injection system 100 configured to supply fuel such as, for example, heavy oil to the injection nozzle 105 of the large internal combustion engine 5,
A fuel injection pump configured to measure fuel, such as heavy oil, for example, in an accurate amount for injection, accumulating high pressure and delivering it to at least one injection nozzle 110 of the large internal combustion engine 5 at a suitable time. 110, the fuel injection pump 110
A pump barrel 10 extending along the longitudinal direction and having a barrel inner wall 12, and
A fuel injection pump comprising a plunger 13 configured to reciprocate in the pump barrel 10 and guided by a barrel wall 12;
At least one scraper ring (210; 220) attached to one of the plunger (13) and the barrel inner wall (12) and configured to slide along the other of the plunger (13) and the barrel inner wall (12).
Fuel injection system 100. The method of claim 1,
And further comprising a first groove 30 formed in the barrel inner wall 12 and a second groove 38 formed in the barrel inner wall 12, wherein the second groove 38 is less than the first groove 30. Is located at a greater distance to the pump chamber,
The scraper ring 220 is positioned to slide in the area between the first groove 30 and the second groove 38,
An additional scraper ring 210 is positioned to slide in the area between the barrel front side facing the plunger foot 19 and the second groove 38.
Fuel injection system. The method according to claim 1 or 2,
At least one scraper ring (210; 220) has a specific elasticity, and the scraper ring (210; 220) is dimensioned to contact and press the barrel inner wall (12) and the plunger (13), respectively, at a certain pressure.
Fuel injection system. 4. The method according to any one of claims 1 to 3,
The at least one scraper ring 210; 220 is selected from the group consisting of a spring ring, a slit ring, a ring comprising at least two individual ring segments, a piston ring and a spring washer.
Fuel injection system. 5. The method according to any one of claims 1 to 4,
The at least one scraper ring 210; 220 is configured to scrape or wipe the precipitate or layer at the contacted surface 12; 13.
Fuel injection system. A fuel injection pump 110 configured for use in the fuel injection system of any one of claims 1 to 5,
The fuel injection pump 110 is configured to measure fuel, such as heavy oil, for example, in precise amounts for injection, accumulating high pressure and at least one injection nozzle 110 of the large internal combustion engine 5 at a suitable time. Pass it on,
The fuel injection pump 110
A pump barrel 10 extending along the longitudinal direction and having a barrel inner wall 12,
A plunger 13 configured to reciprocate in the pump barrel 10 and guided by the barrel inner wall 12;
At least one scraper ring (210; 220) attached to the plunger (13) and configured to slide along the barrel inner wall (12).
Fuel injection pump 110. A method of purging a fuel injection pump 110 configured to pump fuel, for example heavy oil, for example of a large internal combustion engine 5 in a ship or generator set,
The fuel injection pump 110 extends along the longitudinal direction and has a barrel inside wall 12, a plunger configured to reciprocate in the pump barrel 10 and guided by the barrel inner wall 12. Including 13,
The method of purging the fuel injection pump includes mechanically scraping or wiping any deposit on the plunger 13 or the barrel inner wall 12 during the reciprocating motion of the plunger 13.
How to purge a fuel injection pump. A fuel injection system configured to supply fuel such as, for example, heavy oil to the common rail of the large internal combustion engine 5,
A high pressure fuel pump configured to supply fuel to a common rail at high pressure, for example heavy oil, the fuel pump
A pump barrel 10 extending along the longitudinal direction and having a barrel wall 12,
A fuel pump comprising a plunger 13 configured to reciprocate in the pump barrel 10 and guided by the barrel wall 12;
At least one scraper ring (210; 220) attached to one of the plunger (13) and the barrel inner wall (12) and configured to slide along the other of the plunger (13) and the barrel inner wall (12).
Fuel injection system.

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