KR20140005113A - Lubrication system - Google Patents

Abstract

A lubrication system for a piston-in-cylinder device (10) for an internal combustion engine, particularly a large motor or compressor, comprises a pump (1), a lubricant injection element (6), and a connecting line (2) between the pump and the lubricant injection element (6) to supply a lubricant to the lubricant injection element (6). A storage element (4, 44) is applied to the connecting line (2) between the pump (1) and the lubricant injection element (6).

Description

Lubrication System {LUBRICATION SYSTEM}

The invention relates to a lubrication system for a piston-in-cylinder device according to the preamble of claim 1. The invention also relates to an internal combustion engine, in particular a large engine having a piston-in-cylinder device with a lubrication system.

Large engines, especially in the form of large diesel engines, which can be designed as two-stroke internal combustion engines or four-stroke internal combustion engines, are used as drive units in marine or stationary operation, for example to drive large generators for generating electrical energy. Often used. In this regard, large engines generally operate in permanent operation over a significant period of time, which increases the demand for operational safety and operability. Thus, particularly long service intervals, low wear and economical handling of fuel are important criteria for the operator.

In the operating state, the piston slides along the wall of the cylinder, which acts as a movable surface and is usually made in the form of a cylinder liner. In this regard, cylinder lubrication or piston lubrication is provided. On the one hand, the piston should slide in the cylinder as easily as possible, ie without obstacles; On the other hand, the piston should seal the combustion space in the cylinder as tightly as possible to ensure efficient conversion of the energy released in the combustion process into mechanical work.

For this reason, lubricants, usually in the form of lubricating oils, are introduced into the cylinders during operation of large diesel engines to achieve good running characteristics of the pistons and keep wear of the moving surfaces of the pistons and piston rings as low as possible. In addition, the lubricant not only neutralizes the aggressive combustion products but also prevents corrosion. The most expensive and expensive materials are often used as lubricants because of these many demands.

Thus, there is a need to operate with as little lubricant as possible for the particularly efficient and economical operation of the engine. Lubricant consumption is understood as the amount of lubricant that is no longer available for the actual lubrication operation, ie consumed and lost by the lubrication process. This loss can also be caused as the lubricant is bubbled into the combustion gas or dispensed as a lubricating film along the inner cylinder wall. Thus, this lubricant can enter the combustion space in gaseous or liquid form, can be ignited and burned therein, as a result of which it can itself generate sediment in the backfires or in the inner cylinder space. Can not do it.

The proven lubrication process is the so-called internal lubrication which is applied to the piston or to the cylinder moving surface via one or more lubrication sites provided on the surface of the piston after the lubricant has been transferred through the interior of the piston. This process is disclosed, for example, in EP A 0 903 473.

Many possibilities are known for supplying lubricant to the inner cylinder wall of a reciprocating piston combustion engine. The documents EP 2133520 A1 and EP 2253810 A1 represent, for example, a lubrication device with a lubricant reservoir disposed on the piston itself. Thus, this solution relates to the supply of lubricant to the lubrication site through the piston.

Another solution was to reduce the lubricant requirement. On the other hand, an oil collecting ring as known, for example, from EP 2133520 A1 or EP 1 936 245 A1 can be provided. This means that the entry of lubricant into the combustion space can be prevented by the oil collecting ring.

Alternatively or in addition, as disclosed in EP 20 50 946 A1, lubricant can also be supplied to the sliding surface of the piston in the inner cylinder space through the cylinder liner itself and cut-outs in the cylinder liner itself. Can also be accommodated.

The cylinder lubrication of a two-stroke marine diesel engine is caused by metered injection of lubricant, which is currently only injected at approximately every tenth revolution since the pump transfers a constant volume, which is desirable for the distribution of lubricant. I can't. The relatively long line between the pump and the spray nozzle also reduces the dynamics of the system, i.e. the time required for the metering pulse to cover the flow path distance from the pump to the lubricant injection element is too long to accurately define the injection time through the pump. It cannot be adjusted. In addition, as the length of the connecting line increases, the losses due to pipe friction increase so that the pulses at the inlet of the lubricant injection valve can no longer be detected due to the elasticity of the lubricant due to the compressibility in the connecting line.

WO 0235068 A1 represents a fluid actuated lubricant injection element. In this case, a sufficiently high fluid pressure should be available for adjusting the lubricant injection. Measures must also be taken to allow the pressure fluid and lubricant to flow in separate passages. This fluid pressure is generated according to this embodiment using a pump attached to the lubricant injection element and driven by its own motor. According to this solution, a pump and a motor are therefore required for all lubricant injection elements. If multiple lubricant injection elements are provided, this solution thus increases the servicing effort and increases the investment costs. Thus, this solution may be unsuitable for use in polycylinder engines, in particular large marine engines. On the other hand, the maintenance activity should be as small as possible because the engine must be operated in permanent operation over the total travel time of the ship. This means that for reasons of redundancy, a plurality of such fluid operated lubricant deployment elements must be kept excessively in stock. On the other hand, investment costs should be kept as low as possible.

One possibility is provided by the use of a so-called common rail system to provide lubricant to the lubricant injection element, thereby eliminating a plurality of pumps and engines. WO 2011116768 A1 shows such a common rail system for injecting lubricant into a plurality of cylinders of an internal combustion engine. In this system, the aforementioned problem of the connecting line is solved such that the metering of the lubricant takes place directly at the lubricant element via the magnetic control valve. Both the lubricant supply, in fact the supply time of the lubricant to the cylinder and the supply duration of the lubricant, i.e. the amount of lubricant that must be supplied to the lubrication site, can be adjusted very precisely using this magnetic control valve. However, it should be ensured that the supply of lubricant can be started and the lubricant supply can be interrupted again by opening the connection to the lubricant nozzle by a magnetic control valve used for this purpose. Depending on the lubricant pressure, the lubricant supply shutoff may have different lengths until the closing pressure is reached, ie the lubricant volume that reaches the lubrication site is more than provided by the adjustment. Of course, the pressure dependent switching behavior of the magnetic control valve can be set, but this means increasing the adjusting action.

Accordingly, it is an object of the present invention to reduce coordination activity for lubricant metering.

Another object of the invention is to ensure accurate metering of lubricant for lubricating sliding surfaces for pistons along the inner cylinder wall.

Another object of the present invention is to reduce lubricant consumption.

Another object of the present invention is to match the lubricant requirement to the operating state of the internal combustion engine.

These objects of the invention are met by a lubrication system according to claim 1. The dependent claims include further advantageous embodiments of the invention.

Lubrication systems for piston-in-cylinder devices of internal combustion engines, in particular large engines or compressors, comprise a connection line provided between the pump and the lubricant injection element for supplying lubricant to the pump, the lubricant injection element, and the lubricant injection element. . The storage element is provided in the connection line between the pump and the lubricant injection element.

In this connection the storage element can advantageously be located at a short distance from the lubricant injection element and even integrated into the lubricant injection element. The storage element has a defined lubricant volume. Thus, the end of the infusion procedure is predefined as the emptying of the storage element. According to the solution according to the invention, therefore, only the start of the injection of the lubricant has to be adjusted and its end need not be adjusted. Thus, the lubricant injection element need not have a device that blocks the flow of lubricant. Leakage of lubricant also cannot occur with the solution according to the invention.

The solution according to the invention therefore simplifies lubricant metering for internal combustion engines, in particular for piston-in-cylinder devices, in particular for large engines.

The volume per stroke metered into the fully charged storage element may be in the range of 0.03 to 0.5 cm 3, depending on the type of internal combustion engine.

Lubrication rates can range from 0.2 to 2.5 g / kWh. The number of injection elements per cylinder can be 1 to 24, in particular 4 to 24. Injection of lubricant can occur between 0.3 and 3 hours per stroke.

When the stroke is 10 mm, the storage element advantageously has a diameter of up to 8 mm. Ring spaces of approximately 3 mm inner diameter and 4 mm outer diameter may be provided for very small amounts of lubricant. Then, the stroke reaches approximately 5 mm.

Depending on the desired discharge rate of the lubricant through the outlet and / or the desired atomization, the cross-sectional sum of the outlets serving as the injection opening is at most equal to the cross-sectional size of the storage element, in particular at most 1 of the cross-sectional area of the storage element. / 5, particularly preferably at most 1/10 of the cross-sectional area of the storage element. The diameter of each opening is usually in the range of 0.1 to 0.5 mm.

The storage element is filled via a connection line from the pump to the lubricant injection element. Pumps with variable strokes can be used in particular, so that the feed rate can be adjusted to the required amount of lubricant under all load conditions of the internal combustion engine. The lubricant does not return from the lubrication site to the lubrication system, except through a lubricant collection device which may optionally be provided separately. Optionally, the lubricant delivered to the storage element is metered in until the storage element is emptied.

The storage element can in particular be configured as an accumulator, for example as a piston reservoir. A restrictor element can be disposed between the pump and the lubricant injection element. The storage element is replenished after finishing dispensing of lubricant through the restricting element. The limiting element may be designed as a limiting element which is adjustable to match the metered lubricant amount to the operating state of the internal combustion engine. According to one embodiment, the limiting element may also be configured as a magnetic valve or in combination with a multidirectional valve for determining the course of the injection procedure.

According to one embodiment, the storage element comprises a chamber for receiving a lubricant amount corresponding to the maximum required amount of lubricant at the lubrication site. In particular, a plurality of storage elements can be arranged before or after each other or next to each other. That is, at least two storage elements can be connected to one another in series or can be connected to one another in parallel.

Furthermore, a common storage element can be provided for the plurality of lubricant injection elements. Alternatively or in addition, a single lubricant injection element or a plurality of lubricant injection elements can be connected to the plurality of storage elements. The storage elements can have chambers with different volumes and / or the volume of each storage element can be variable. The connection line may comprise at least one restriction element between the pump and the storage element. The limiting element may have at least one setting element for varying the flow cross section. Thus, the filling speed of the storage element can be set by the adjustable limiting element.

According to one embodiment, the pump may have setting means for changing the conveying amount per unit time. The pump may in particular be configured as a geared pump that can be adjusted by speed or as a piston pump with an adjustable stroke.

According to one embodiment, the lubricant injection element may comprise a storage element. This embodiment allows a very compact configuration of the lubrication system. It can also be ensured by this device that the metering is triggered as soon as the lubricant demand is signaled. The lubricant injection element has in particular a housing element, an inlet for lubricant disposed in the housing element as well as a storage element in fluid communication with the inlet and disposed inside the housing element. The storage element has an outlet that can be closed by an opening and closing element as well as a chamber configured to receive lubricant. The opening and closing element can be moved by an actuation element so as to release the outlet for dispensing lubricant.

The restricting element can be arranged between the inlet and the storage element such that a large amount of lubricant that occurs in the short period between the end of the emptying of the storage element and the closing of the magnetic valve is reduced to an unsuitable amount. Alternatively, at least one additional magnetic valve without special requirements for kinematics may be used instead of the limiting element because the lubricant supply can be interrupted for a long time before the injection procedure begins and can be opened again after the end of the injection procedure. Can be used. As a further alternative, the injection magnetic valve can be extended to form a multidirectional valve or can be replaced with a multidirectional valve. According to one embodiment, the chamber may have a displacement element such that the volume of the chamber can be varied. The lubricant injection element can in particular comprise a needle valve.

The internal combustion engine may comprise a lubrication system according to any of the preceding embodiments. The internal combustion engine comprises a piston-in-cylinder arrangement, the piston-in-cylinder arrangement comprises a cylinder and a piston, the cylinder having a cylinder jacket delimiting the inner cylinder space. The cylinder jacket comprises at least one lubricant injection element according to any of the preceding embodiments.

The method for lubricating a piston-in-cylinder device of an internal combustion engine includes a piston-in-cylinder device. Lubricant is supplied to the lubrication site of the piston-in-cylinder device by a lubrication system. The lubrication system includes a connection line provided between the pump and the lubricant injection element to supply lubricant to the pump, the lubricant injection system and the lubrication injection element. The storage element is provided in the connection line between the pump and the lubricant injection element. Lubricant is transferred by the pump to the connecting line and to the storage element; For a long time until the storage element is at least partially empty, from the storage element, the lubricant is transferred to the lubrication site through the lubricant injection element.

The lubricant injection element has in particular an operating element which releases the outlet at the housing element of the lubrication element such that the lubricant reaches the lubrication site.

The lubricant injection element includes a restriction element disposed between the inlet and the storage element such that the storage element is replenished after at least some emptying. Advantageously, the replenishment duration can be adjusted via the feed rate of the pump.

The above description and embodiments serve only as an example to illustrate the operation of the invention. Further advantageous embodiments can be seen from the dependent claims and the figures. In addition, individual features from the described and illustrated embodiments can be combined as desired within the framework of the invention.

The invention will be explained in more detail below with reference to the accompanying drawings.

1 is a cutaway view through a lubrication system as well as a piston-in-cylinder device according to a first embodiment of the invention.
2 is a graph of pressure by volume (PV plot).
3 is a cutaway view through an embodiment of a lubricant injection element.
4 shows a lubrication system according to a second embodiment.

The design of the lubrication system presented is shown schematically in FIG. 1. A pump 1 that can be adjusted, for example a geared pump that can be speed adjusted or a piston pump with an adjustable stroke, transfers lubricant to the connection line 2 to which all lubricant injection elements 6 are connected. do. Of course, only one lubricant injection element 6 can also be provided; However, there may also be a plurality of lubricant injection elements. The lubricant injection element (s) 6 are arranged in the cylinder wall or cylinder liner. The conveying pressure is selected according to the desired amount of injection of lubricant. The lubricant is conveyed to the one or more storage elements 4 via the limiting element 3. The storage element 4 can be designed, for example, as a piston opening element or a pneumatic storage element. The injection procedure is triggered by an opening and closing element, for example a magnetic valve 5. With an open magnetic valve, the needle valve of the lubricant injection element 6 is opened so that lubricant is introduced into the intermediate space between the cylinder 20 and the piston 11 at the lubrication site and lubricated from the intermediate space at the inner cylinder wall or piston ring. May be introduced into the site. The amount of lubricant flowing out of the supply line 2 is limited by the limiting element 3 so that the filling procedure ends when the storage element (s) 4 are empty. According to an alternative solution not shown in the figure, a single magnetic valve may be provided to adjust the lubricant supply to the lubricant injection element. This means that the branch of the lubricant line does not occur between the storage element 4 and the two magnetic valves 5 but only behind the magnetic valve 5 as shown in FIG. 1.

The piston-in-cylinder device 10 according to FIG. 1 comprises a piston 11 as well as a cylinder 20. The cylinder 20 has a cylinder jacket 17 that delimits the inner cylinder space 18. The piston 11 has a piston jacket surface 35, a piston upper surface 36 and a piston lower surface 37. The piston jacket surface 35, the piston upper surface 36 and the piston lower surface 37 delimit the piston body 25. The piston body 25 may consist of a plurality of parts, for example it may comprise a piston head 38 and a piston skirt 39. The piston body 25 can at least partly have a hollow space 40 through which coolant can be introduced into the piston body 25. A groove 12 is formed in the piston jacket surface 35 through which grooves lubricant can be added to the inner cylinder wall and the piston ring of the sliding pair or through which the lubricant can be removed from the surface of the inner cylinder wall. Can be. The intermediate space 16 is formed by the groove 12 between the piston jacket surface 35 and the cylinder jacket 17. The groove 12 may extend with respect to the peripheral portion of the piston jacket surface 35. A plurality of such grooves may in particular be provided at the periphery of the piston jacket surface, which is not shown in the figure.

The cylinder 20 has a cylinder jacket 17 that includes a plurality of flushing openings 19. The cylinder 20 has a cylinder head 21 having an inner surface 22 adjacent to a cylinder jacket 17, the combustion space 23 of which is the top of the piston, the cylinder jacket 17 and the cylinder head 21. The boundary is defined by the inner surface 22. The flushing space 24 is adjacent to the piston lower surface 6, and the fluid pressure inside the cutout 11 is less than the pressure in the combustion space and less than the pressure in the flushing space 34.

The first piston ring 14 and the second piston to form an intermediate space 16 comprising a groove 12, bounded by a piston ring 14, a piston jacket surface 35 and a cylinder jacket 17. The ring 15 is arranged on the piston jacket surface 35 of each groove. A plurality of such grooves may be provided parallel to one another, especially at the periphery of the piston jacket surface, which is not shown in the figure. The piston ring 14 forms a substantially gas tight connection with the combustion space 23. The piston ring 15 does not have a gas tight design. It may also be formed as a lubricant scraping ring.

2 shows the possible properties of the lubrication system. The volume is plotted on the x axis and the injection pressure is plotted on the y axis. This property relates to a storage element with two spring elements. The relationship between the injection pressure and the stored volume can be influenced by the direction of action of the spring stiffness, preload and / or abutment. Only spring elements are loaded in the pressure range between P ₀ 8 and P _n 9. At the point corresponding to P _n 9, the piston moves to the adjacent part and the adjacent part moves with a second spring element arranged coaxially, for example connected in parallel. As a result, a so-called progressive characteristic occurs, which is greatly disproportionately increased as the volume increases. In principle, it is also possible to generate a degressive characteristic with two spring elements, for example in that the spring elements are connected back and forth with each other and the adjacencies are used between the spring elements. The falling characteristic can be advantageous to keep the pressure change small during the injection.

3 shows a cut through the embodiment of the lubricant injection element 6. The lubricant injection element 6 has a housing element 26, in which an inlet 27 for lubricant is arranged, through which the lubricant injection element 6 reaches this inlet via a connection line from the pump. The inlet 27 is optionally arranged in a housing element 26 consisting of a plurality of parts. In addition, a storage element 4 in fluid communication with the inlet 27 and arranged inside the housing element 26 is located in the housing element 26. The storage element 4 has an outlet 30 which can be closed by an opening and closing element 31 as well as a chamber 28 configured to receive lubricant. The opening and closing element 31 can be moved by the operating element 32 so that the outlet 30 can be released for dispensing the lubricant. Of course, multiple outlets 30 can be provided.

The restricting element 3 is arranged between the inlet 27 and the storage element 4. The limiting element 3 consists of a passage in a housing element which extends partially in the shape of a ring. Of course, the limiting element can also have a shape different from the shape shown in FIG. 3. The storage element 4 has a displacement element 29 which protrudes into the chamber 28 and can move back and forth in the chamber 28 to vary the volume of the chamber 28. The displacement unit 29 is displaced by its spring element 33 to its lowest position in FIG. 3. The volume of the chamber 28 is the smallest at this position. If the internal pressure of the lubricant in the chamber 28 is greater than the pressure exerted by the spring element 33 on the displacement element 29, the displacement element 29 moves upward against the elastic force of the spring element 33. If the pressure becomes too high, the outlet 42 is released by the displacement element 29 so that the lubricant injection element is also safe against excess pressure.

If the displacement element 29 is in the upper vicinity, excess lubricant is removed through the leak opening 41 to allow rapid movement of the displacement element 29. In this case, the lubricant passing through the leak opening can be detected by the detection mechanism so as to detect a leak in the system and optionally trigger an alarm.

Alternatively to the leak opening 41, the displacement element cannot also be designed as a piston in the mounting area of the spring element, but rather a gap can be maintained between the displacement element and the housing, which gap is not shown in the figure. In normal operation, the displacement element 29 must not reach the adjacency, ie the spring 33 must not be fully compressed. The filling procedure is limited by the balance of forces between the spring element 33 and the displacement element 29 designed as a ring piston.

4 shows a lubrication system according to a second embodiment different from the embodiment according to FIG. 1 in that there is a second storage element 44 in addition to the storage element 4. The first storage element 4 is arranged in an arrangement parallel to the second storage element 44. According to this embodiment, both storage elements are charged simultaneously. Of course, filling or emptying of one of the storage elements can be accelerated or decelerated relative to the other storage element using different spring stiffness. Alternatively, the storage element 4 can be arranged behind the storage element 44 in the flow direction. In this case, the storage element 44 is first charged before charging the storage element 4. A separate opening and closing element, for example a magnetic valve, must be provided for each of the two storage elements. This device can be advantageous if it must cover very largely different operating states.

Claims (15)

As a lubrication system for an internal combustion engine, in particular a piston-in-cylinder device 10 of a large engine or compressor,
A pump 1, a lubricant injection element 6, and a connecting line 2 provided between the pump and the lubricant injection element 6 for supplying lubricant to the lubricant injection element 6,
A lubrication system, characterized in that a storage element (4, 44) is provided in the connection line (2) between the pump (1) and the lubricant injection element (6). The method of claim 1,
A restrictor element (3) is arranged between the pump (1) and the lubricant injection element (6). 3. The method according to claim 1 or 2,
The storage element (4, 44) comprises a chamber for receiving an amount of lubricant corresponding to the maximum requirement at the lubrication site. The method according to any one of claims 1 to 3,
A lubrication system in which a plurality of storage elements (4, 44) are arranged before and after each other or next to each other. 5. The method according to any one of claims 2 to 4,
The limiting element (3) has a regulating element for varying the cross section of the flow. 6. The method according to any one of claims 1 to 5,
The pump (1) has setting means for varying the feed amount per unit time. 7. The method according to any one of claims 1 to 6,
The lubricant injection element (6) comprises the storage element (4). As lubricant injection element (6),
A housing element 26, an inlet 27 for lubricant disposed in the housing element 26, and a storage element 4 in fluid communication with the inlet 27 and disposed inside the housing element 26. ),
The storage element 4 has a chamber 28 that is configured to receive lubricant and has an outlet 30 that can be closed by an opening and closing element 31, in which the outlet 30 dispenses lubricant. The opening and closing element (31) is movable by the operating element (32) so that it can be released. The method of claim 8,
A restricting element (3) is arranged between the inlet (27) and the storage element (4). 10. The method according to claim 8 or 9,
The lubricant injection element (28) has a displacement element (29) so that the volume of the chamber (28) can be varied. An internal combustion engine comprising the lubrication system according to claim 1,
The internal combustion engine comprises a piston-in-cylinder device 10,
The piston-in-cylinder device 10 includes a cylinder 20 and a piston 11,
The cylinder 20 has a cylinder jacket 17 that delimits the inner cylinder space 18,
The internal combustion engine comprising a lubrication system, wherein the cylinder jacket comprises at least one lubricant injection element (6) according to any of the claims 8-10. As a method of lubricating the piston-in-cylinder device 10 of an internal combustion engine,
Lubricant is supplied to the lubrication site of the piston-in-cylinder device 10 by a lubrication system,
The lubrication system comprises a connection line provided between the pump 1 and the lubricant injection element 6 for supplying lubricant to the pump 1, the lubricant injection element 6, and the lubricant injection element 6. 2),
Storage elements 4, 44 are provided in the connecting line 2 between the pump 1 and the lubricant injection element 6,
The lubricant is conveyed by the pump (1) to the connection line (2) and to the storage element (4),
A lubricant is transported through the lubricant injection element (6) to the lubrication site for a long time until the storage element (4) is at least partially emptyed. 13. The method of claim 12,
The lubricant injection element 6 has an operating element 32 for releasing the outlet 30 at the housing element 26 of the lubricant injection element 6 so that lubricant reaches the lubrication site. How to lubricate the piston-in-cylinder device. The method according to claim 12 or 13,
The lubricant injection element 6 comprises a limiting element 3 disposed between the inlet 27 and the storage element 4 such that the storage element 4 is replenished after at least some emptying. To lubricate the piston-in-cylinder device. 15. The method according to any one of claims 12 to 14,
The replenishment duration is controlled via the feed rate of the pump (1), the method of lubricating a piston-in-cylinder device of an internal combustion engine.

Images