KR20010089772A - Reciprocating piston engine - Google Patents

Abstract

The present invention relates to a reciprocating piston engine having at least one cylinder, wherein the cylinder liner 2 of the cylinder is provided with at least one groove 9 forming an oil pocket 8, which is the movable surface of the liner. By being located in area (4), the movable surface 4 faces the piston 6 associated with the cylinder. The object of the present invention is in particular for protecting the operating mode, so that the life of the cylinder liner 2 is particularly long. Due to this, the groove 9 has a depth corresponding to the maximum wear depth of the cylinder liner 2. In the groove 9, a charging unit 10 is located. The material used for the filling part in the groove 9 has a lower wear resistance than the substrate of the cylinder liner 2.

Description

Reciprocating-piston engine {RECIPROCATING PISTON ENGINE}

A reciprocating-piston internal combustion engine of this type is disclosed in British Patent No. 173058. In the known device, the cross section of one or a plurality of oil pockets, each corresponding to a cross section of the associated groove, is cut by a cylinder lining. The depth of the groove is reduced due to the gradual wear of the cylinder lining. The depth of the oil pocket formed by the grooves themselves is also reduced to the same extent as known devices. Therefore, it results in worsening the condition of life extension. In addition, a disadvantage of the particularly known apparatus is the fact that material particles which have come off the cylinder lining, for example as a result of corrosion by heat or the like, cannot be fixed in the grooves of the known apparatus. Therefore, the material particles get caught between the cylinder lining and the piston, causing them to crumble or chip, resulting in damage or localized heating, thereby risking accelerated heat corrosion and / or sticking. Therefore, it has been found that known devices cannot be operated sufficiently reliably.

The present invention relates to a reciprocating-piston engine, in particular having at least one cylinder and provided with at least one groove in the cylinder lining in the region of the movable surface facing the associated piston of the cylinder, thereby providing an oil pocket. To a large two-stroke diesel engine.

1 is a partial cross-sectional view of a cylinder of a large two-stroke diesel engine.

2 is an enlarged view of a portion of the movable surface of a cylinder lining provided with grooves according to the invention.

3 is a sectional view of a deformation of the groove.

4 is a cross-sectional view of another variant of the groove.

Therefore, against this background, it is an object of the present invention to improve to a type of device of high reliability for a long time using simple and inexpensive means while avoiding the disadvantages of the device described above.

This object is achieved according to the invention in which the depth of the filling part in relation to the groove corresponds to at least the maximum wear thickness of the cylinder lining and the material filling the groove is less wear resistant than the substrate of the cylinder lining.

In an improved state, the groove is completely filled by the associated filling. Therefore, the smooth surface makes machining easier. However, the fact that the filling part wears out earlier than the substrate as early as possible in the running state allows to form the desired oil pocket, the depth of which is shallower than the depth of the groove, and as the wear of the cylinder lining increases. Its size progresses. This maintains a substantially uniform condition for the cross section of the oil pocket for a long time, despite the shallow depth of the groove, and ensures reliable lubrication for a long time in the relevant area of the cylinder lining to prevent corrosion and Reliably prevent sticking The depth to form one or a plurality of oil pockets is related to the strength of wear. The higher the wear, the deeper the oil pocket is for more effective lubrication. On the contrary, the lower the wear, the smaller the oil pocket is for lubrication. Thus, it is almost self-regulating. Therefore, it is possible to reduce the consumption of certain oils. In addition, an advantage of the method according to the invention is that the particles of the material coming off the cylinder lining due to inevitable wear are compressed into a relatively soft packing and fixed in this way. Therefore, the free movement of the material particles is stopped by the groove provided with the filling part. Grooves provided with live parts according to the invention thus have the function of a very effective stop groove. Thus, the method according to the invention effectively prevents damage and disturbances, for example by material particles falling out of the liquefied and / or solidified cylinders, which will accelerate thermal corrosion and crushing. . Therefore, long life is advantageously ensured by the present invention.

Preferred details and extensions of the method are described in the dependent claims. The material filling the grooves can provide higher thermal expansion than the substrate of the cylinder lining. The effect achieved thereby is to prevent the so-called seizure by expanding faster than the substrate and stabilizing the piston when the live part is overheated. This advantage is further enhanced when the live part preferably has dry lubricity.

In detail the method, the filling part of the groove may comprise at least partially aluminum and / or aluminum-copper and / or graphite, which preferably comprises 9-11% Al, 0.5-2% Including Fe and the rest of Cu may be used. This type of material contains to a considerable extent the desired components described above. However, for example, a graphite alloy preferably containing 15-25% graphite and 75-85% aluminum-copper may also be used. The material also contains the desired components to a significant extent.

At least one spiral groove may preferably be provided. This results in good distribution and especially good delivery of oil over a wider area of the cylinder lining, thereby increasing reliability.

In further detail, the method has a welded or spray-coated form depending on the stability of the material used. It is ensured in a simple manner that the substrate is reliably stuck and filled without defects.

Further advantageous improvements and developments of the method are described in the dependent claims and will become more apparent from the embodiments with reference to the accompanying drawings.

The present invention is used in reciprocating-piston engines, in particular reciprocating-piston internal combustion engines, with the preferred form of large two-stroke diesel engines of low speed. The structure and mode of operation of such a device are known and are not described herein.

The cylinder of the large two-stroke diesel engine shown in FIG. 1 includes a cylinder lining 2 provided with an intake slot 1, and is mounted thereon with a cylinder head 3 including an exhaust device not shown in detail. The interior of the cylinder lining 2 is designed with a movable surface 4 to cooperate with the reciprocating piston 6 provided with a piston ring 5 on the outer periphery. The lubricating oil is supplied to the movable surface 4 via the lubricating oil supply line 7.

In order to distribute the lubricating oil well, in particular in order to provide good lubricating oil in the upper region of the movable surface 4, for example, in which the lubricating oil supply is insufficiently empirically, an appropriate oil pocket 8 is provided. This is shown simply in FIG.

For the foregoing purposes, as shown in detail in FIG. 2, at least one cut groove 9 is provided in a part of the movable surface 4, in which an associated oil pocket 8 is formed. The groove 9 comprises a filling 10 made of a material that is less wear resistant than the substrate of the cylinder lining. The cylinder lining is usually made of cast steel. Aluminum-copper is preferably used to form the charging section 10. As demonstrated by the experiment, the aluminum-copper comprises at least 2-20% Al, preferably 9-11% Al, 0.5-8% Fe, preferably 0.5-2% Fe and the balance Cu. . The composition ratio is adjusted to the given environment in each case. The higher the Fe content, the higher the hardness of the material. In the case of the cylinder lining of a large two-stroke diesel engine, good results were obtained by using aluminum-copper having the following composition.

2-20%, preferably 9-11% Al,

0.5-8%, preferably 0.5-2% of Fe,

0.1-8% Mn, 0.1-2% Si, 0.1-1% Ni, 0.1-2% C,

In each case at least 5-20% of Sb, Co, Be, Cr, Sn, Cd, Zn, Pb,

And Cu.

However, in each case nickel-graphite or silicon-graphite or aluminum-graphite comprising 5 to 60%, preferably 15 to 25% graphite, and 40 to 95%, preferably 75 to 85% of each other component Or aluminum-copper-graphite. The use of aluminum-copper-graphite alloys results in particularly good resistance to corrosion and seizure. The composition of the aluminum-copper may be the case corresponding to the above-described composition.

The filling unit 10 is preferably formed in the groove 9 formed in advance as a spray coating made by a laser spraying technique such as a plasma spraying technique or an arc spraying technique. Of course, the filling part 10 of the groove 9 may be made by welding coating. Aluminum-copper comprising 9-11% Al, 1-3% Fe, 4-6% Ni, 1-2% Mn and the rest Cu is particularly suitable for this purpose.

In this case it is convenient for the groove 9 to be filled up to the height of the movable surface 4. Then, the movable surface 4 is honed entirely, for example. Since the material forming the filling section 10 is less wear resistant than the substrate of the cylinder lining 2, the filling section 10 wears faster than the cylinder lining 2 at the beginning of operation. The corroded material is washed away by lubricating oil and held in the oil pocket 8 until the end of the life of the cylinder lining 2.

The depth of the groove 9, denoted by d in FIG. 2, corresponds at least to the wear thickness of the cylinder lining 2, preferably slightly deeper. However, since the deep groove 9 is provided with a filling part 10 which likewise wears according to the wear of the cylinder lining 2 and wears only slightly faster, the cross-sectional shape of the oil pocket 8 is the same as that of the cylinder lining 2. It is generally uniform over its lifetime and produces different results than the cross section of the groove 9 itself.

It is preferable to use a material for forming the filling section 10 that has greater expandability than the substrate of the cylinder lining under the influence of heat. The previously proposed material has these characteristics. Therefore, when locally overheated, the filling section 10 expands larger than the substrate of the cylinder lining 2, resulting in the piston 6 being stabilized by the discontinuous expansion line 11, as shown in FIG. You will be able to import. The material proposed for the live part 10 also has good dry lubricity, which is particularly advantageous in the case of overheating. However, it is also possible to incorporate and / or incorporate additional materials with good dry lubricity in the filler.

The groove 9 may be provided with one or more. According to the conventional experience, they are appropriately disposed at a position where there is insufficient lubrication and there is a risk of corrosion due to heat. In this case, in particular, the upper region of the movable surface 4 becomes. In FIG. 1, the region of the movable surface 4 defined by the first and second piston rings 5 in the top dead center position of the piston 6 is provided with an annular groove with the corresponding oil pocket 8. do. The area under the lower piston ring 5 is provided with an additional groove with an associated oil pocket 8. In the illustrated example there are shown many further oil pockets 8 arranged deeper.

The groove 9 forming the base of the oil pocket 8 has an annular radial groove shape. In addition, or alternatively, however, one or a plurality of spirally extending grooves 9 with oil pockets associated therewith may be provided. It may extend over one area or the entire length of the movable surface 4.

2 is a view of a groove 9 extending in a helical manner. The lead of the groove 9, denoted by P, may be 1.5% -20% of the diameter D of the movable surface 4. Lead P is constant over the entire length of the groove. However, it is possible to vary the length of the lead to obtain more oil pockets, especially in areas that are more prone to wear than in other areas. The depth of the groove 9 described above is preferably in the range between 0.1%-0.4% of the diameter D.

In the illustrated example, the groove 9 has a cross section in which the initial width w narrows inward. This is because the wear rate increases with time. In FIG. 2, the groove 9 has a substantially U-shaped cross section with a flank inclined with respect to the bottom of the groove. The angle of inclination of the flank is represented by α, and may be in the range of 30 ° -60 °. The transition between the groove bottom and groove flank is preferably rounded as indicated by the radial arrow.

The dimensional data may be applied to various further forms shown in FIGS. 3 and 4. 3 shows a V-shaped groove 9 with an associated filling part 10 comprising an oil pocket 8. The groove 9 shown in FIG. 4 has an arc shaped cross section. In this case as well, the cross section narrows inward so that the width of the charging section 10 decreases inward and an oil pocket 8 is formed therein.

See above

Claims (18)

At least one groove 9 is provided in the cylinder lining 2 having at least one cylinder and in the region of the movable surface 4 facing the associated piston 6 of the cylinder to form an oil pocket 8. For reciprocating piston engines, especially large two-stroke diesel engines, The filling part 10 is associated with a groove 9 having a thickness at least corresponding to the maximum wear thickness of the cylinder lining 2, and the material forming the filling part 10 of the groove 9 is the cylinder lining 2. Less wear-resistant than the substrate Reciprocating piston engine. The method of claim 1, A material for forming the filling portion (10) of the groove (9) exhibits higher thermal expansion than the substrate of the cylinder lining (2). The method according to claim 1 or 2, A reciprocating-piston engine in which the material forming the filling section (10) of the groove (9) has dry lubricity. The method according to any one of claims 1 to 3, A reciprocating-piston engine in which the material forming the filling section (10) of the groove (9) comprises at least partially aluminum and / or aluminum-copper and / or graphite. The method of claim 4, wherein The aluminum-copper used to form the filling section (10) of the groove (9) contains at least aluminum, iron and copper. The method according to any one of claims 1 to 5, The aluminum-copper used to form the filling portion 10 of the groove 9 is at least, 2-20%, preferably 9-11% Al, 0.5-8%, preferably 0.5-2% of Fe, and Cu of rest Reciprocating-piston engine comprising an alloy composition. The method according to claim 5 or 6, The aluminum-copper used to form the filling portion 10 of the groove 9 is at least, 2-20%, preferably 9-11% Al, 0.5-8%, preferably 0.5-2% of Fe, 0.1-8% Mn, 0.1-2% Si, 0.1-1% Ni, 0.1-2% C, At least 5-20% of Sb, Co, Be, Cr, Sn, Cd, Zn, Pb in each case, and Cu of rest Reciprocating-piston engine comprising an alloy composition. The method according to any one of claims 4 to 7, The material forming the filling portion 10 of the groove 9 is 5-60%, preferably 15-25% graphite, and 40-95%, preferably 75-85% aluminum and / or aluminum- A reciprocating-piston engine comprising copper and / or nickel and / or silicon. The method according to any one of claims 1 to 8, A reciprocating-piston engine provided with at least one helical groove (9). The method according to any one of claims 1 to 9, A reciprocating-piston engine provided with at least one groove (9) in at least the upper region of the cylinder lining (4). The method according to any one of claims 1 to 10, A reciprocating-piston engine in which at least one groove (9) is provided in the region of the movable surface (4) defined by at least first and second piston rings (5) in the top dead center position of the piston (6). The method according to any one of claims 1 to 11, A reciprocating-piston engine in which at least one groove (9) is provided in at least the lowermost piston ring (5) lower region in the top dead center position of the piston (6). The method according to any one of claims 1 to 12, At least one groove (9) extends continuously throughout the guide length of the movable surface (4). The method according to any one of claims 1 to 13, The lead of the helical groove (9) is 1.5% -20% of the diameter of the movable surface (4). The method according to any one of claims 1 to 14, The depth of the groove (9) is a reciprocating-piston engine of 0.1%-0.4% of the diameter of the movable surface (4). The method according to any one of claims 1 to 15, An initial width of the groove (9) is a reciprocating-piston engine, wherein 1%-2% of the diameter of the movable surface (4). The method according to any one of claims 1 to 16, The groove (9) is a reciprocating piston engine having an inwardly tapered cross section. The method according to any one of claims 1 to 17, The filling part (10) of the groove (9) is a reciprocating piston engine having a welded or spray-coated form.