JP2010242761A - Reduction device for gas pressure applied to piston ring package of reciprocating engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for improving a seal between a combustion chamber and the piston lower side particularly near the piston top dead center, and to always automatically attain an optimal seal between a piston head and an anti-polishing ring near the piston top dead center, regardless of an operation state and an abrasion state of a related component, by reducing gas pressure acting on a piston ring package in operation. <P>SOLUTION: A scraping device 5 and the piston head 23 are constituted and mutually arranged so that they are mutually inclined at least partially at a settable angle α at the stopping temperature, and thus, when the piston head 23 cooperates with the scraping device 5 near the top dead center OT, reduction in the gas pressure P acting on the piston ring package 22 is automatically adjusted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a piston ring package of a reciprocating engine, a piston, a removable scraping ring, a device for reducing gas pressure applied to a cylinder, and a reciprocating engine according to the upper conceptual part of the independent claim, In particular, it relates to a two-cycle large diesel engine.

  Pistons known from the prior art for reciprocating engines, for example for two-cycle large diesel engines, in particular for uniflow scavenging two-cycle large diesel engines, typically consist of a plurality of piston rings arranged vertically in each piston ring groove. It has a package consisting of Known piston ring packages usually consist of at least two piston rings, but mostly depend on the magnitude or structure of the output of the reciprocating engine or on the requirements and special operating conditions of the engine operation. It consists of three, four, and even five. In this case, the plurality of piston rings have completely different functions. For example, distribution and / or scraping of lubricant oil on the cylinder sliding surface, sealing of the combustion chamber to the crankcase, sealing to the receiving chamber in the case of a uniflow scavenging two-cycle large diesel engine.

  Typically, in the case of a uniflow scavenging two-cycle large diesel engine, four or five piston ring packages are used to seal the combustion chamber against the underside of the piston facing the receiving chamber. From the receiving chamber, fresh air flows into the cylinder combustion chamber through the scavenging port at the beginning of the scavenging stage. Depending on the ring joint, the lower multi-piston ring is subject to significant loads, with some differences. In that case, different unstable states often occur between the lower piston rings, and these unstable states cause, for example, pressure fluctuations, which in turn cause unstable movements of the piston. This is because there are too many piston rings with similar or equal functions.

  Large diesel engines are often used as ship drives or as stationary drives, for example large generator drives for generating electrical energy. In that case, since the engine operates continuously for a considerably long time, high demands are imposed on the safety and effectiveness of operation. Thus, for operators, long maintenance intervals, low wear, and economics with respect to fuel and working materials are the central criteria for engine operation. In particular, the operation of the piston of a slow diesel engine having a large cylinder hole is a decisive factor relating to the length and effectiveness of the maintenance interval and directly in terms of operating costs and in terms of economy, in terms of lubricating oil consumption. For this reason, the complex problem of engine cylinder lubrication is becoming increasingly important. In particular, in the case of a large diesel engine, the cylinder is lubricated by a lubrication device in a reciprocating piston or by a lubricating oil nozzle provided in the cylinder wall.

  The problem that occurs repeatedly during the operation of the internal combustion engine is combustion residue adhering to different locations in the engine. In particular, in the case of a two-cycle large diesel engine that is often operated with heavy oil, combustion residue is a major problem. This is because the fuel used, that is, heavy oil, contains many substances that generate solids, liquids, gases, and all kinds of combustion residues, and these residues adhere to pistons, piston ring grooves, in particular piston heads or cylinders. In particular, it adheres near the top dead center.

  In order to scrape off the combustion residues of the piston head in particular, it is known, for example in the case of a two-stroke engine from the company Waertsilae, to have a so-called anti-polishing ring on the top of the cylinder liner. It is configured as a thin-walled sleeve having a cross section and usually has an inner diameter that is smaller than the inner diameter of the cylinder itself. This diameter reduction creates a scraping effect at the piston head. The inner diameter of the anti-polishing ring is then determined by the diameter of the piston head and the maximum diameter of the piston head during engine operation. Therefore, in the case of known anti-polishing rings, it is required that the inner diameter be designed so that the gap between the piston head and the ring is as small as possible and that the piston head is not in direct mechanical contact with the ring.

Obviously, the configuration of the anti-polishing ring must be compromised in numerous ways. When the load is low and the piston head is cold, the thermal expansion effect is low, so that play alone, that is, the piston head / ring interval is larger than that under high load. In that case, the additional consideration is generally that the various components in the cylinder, for example the cylinder sliding surface, the piston, in particular the piston ring, the piston ring groove, both in the circumferential direction and in the longitudinal direction, including the piston head, However, it wears variously depending on the number of operating hours, and therefore does not have a constant diameter.
Thus, in the case of prior art known engines, it is clear that the anti-polishing ring and the piston head do not cooperate optimally under all operating conditions and over the entire useful life of the components involved. .

  In particular, when the anti-polishing ring and the piston head are both close to top dead center and are actually sealed, the optimum sealing effect is not always guaranteed between them. In addition to scraping off combustion residues, the important role of the anti-polishing ring / piston head pair is to generate a very high gas pressure generated in the cylinder combustion chamber near the top dead center of the piston during the compression stroke, that is, during fuel ignition. Sealing against the underside, and in particular against the piston ring package below the piston head.

  Therefore, it must be particularly ensured that the pressure energy generated near top dead center in the combustion chamber is made available as completely as possible, and is squeezed through the piston in the form of a gas flow to the lower part of the cylinder. It is to make sure that no part flows into the receiving chamber. In addition, if the seal between the anti-polishing ring / piston head is inadequate, the gas flow that rubs down the piston and flows downward will cause individual particles to be uncontrollably stripped from the deposits of combustion residues, For example, it often adheres to the cylinder sliding surface at the bottom of the cylinder, thereby naturally contaminating the cylinder lubricant, and in the worst case there is always a risk of causing damage such as scraping.

  The object of the present invention is therefore to provide a device which helps to improve the seal between the combustion chamber / bottom piston, especially near the top dead center of the piston. In particular, it is an object of the present invention to reduce the gas pressure acting on the piston ring package during operation, and the piston head / anti-near piston near top dead center, regardless of the operating state or the wear state of the components involved. It is to ensure that the optimum seal between the polishing rings is always achieved automatically.

The subject matter of the present invention which solves this problem has the features described in the independent claims.
The dependent claims relate to particularly preferred embodiments of the invention.

  The invention therefore relates to a device for reducing the gas pressure acting on a piston ring package arranged in a piston ring section during operation of a reciprocating engine. The piston then includes a piston head adjacent to the piston ring section, which is located on the combustion chamber side of the reciprocating engine in the assembled state. The piston is arranged to reciprocate along the longitudinal axis of the cylinder in operation, so that the piston head of the piston is scraped off on the cylinder wall near the top dead center of movement in the cylinder. Control scraping of combustion residue in cooperation with the device. In this case, the gas pressure reducing device is configured in a notch form, and adhesion of combustion residues to the reducing device can be controlled. The scraping device and the piston head according to the present invention are constructed and interleaved so that they are at least partially inclined with respect to each other at a pre-settable angle at least at a stop temperature, whereby the piston head is scraped off near top dead center In cooperation with the device, the gas pressure acting on the piston ring package is automatically adjustable and reduced.

The concept of “stop temperature” in this case means the temperature that the engine exhibits after waiting for a sufficiently long time in a non-operating state. Thus, the stop temperature may be understood as effectively the ambient temperature if the engine has been stopped for a sufficiently long time and is substantially equal to the ambient temperature. To distinguish from ambient temperature, the operating temperature of the engine or various parts of the engine must be known. As is well known to those skilled in the art, the operating temperature is the temperature that the engine or individual parts of the engine exhibit in operation.
An important advantage for the present invention is that the cross section (interval) between the cylinder, i.e. the scraping device or gas pressure reducing device, and the piston head changes.

It is preferable that the constituent members, that is, the scraping device, that is, the reduction device and the piston head are configured not to be parallel to each other in the normal temperature state, that is, at the stop temperature. In that case, the scraping device, that is, the opposing surface of the reduction device and the piston head can be configured in any one of a spherical shape, a corrugated shape, and a stepped shape, for example.
The piston head preferably has a tapered conical shape towards the combustion chamber, and the scraping ring closes towards the combustion chamber or vice versa depending on the degree of deformation. . In another embodiment, it goes without saying that only one of the two opposing surfaces can preferably have a cross section in which the piston head varies.

In that case, a particular advantage of the present invention is that the components are heated in operation, so that the notched form, e.g. the surface shaped in the groove form or the non-shaped face, is opposed in an optimal manner, thereby The desired seal is achieved, for example, by a labyrinth of a notch with or without a residue attached.
In the meantime, the cross-section closing towards the combustion chamber, in particular the shrinking cross-section, results in a better seal without residue deposits. This is because the smallest cross section is located closest to the combustion chamber.
The cross section that is open towards the combustion chamber, in particular the enlarged cross section, on the other hand, results in a more rapid deposition of soot particles, due to the anticipated temperature rise and cross section increase.

The reduced or enlarged cross section preferably has an angle of about 0.238 ° to 0.7 °, usually with respect to the normal and to the cylinder longitudinal axis.
In particular, according to the present invention, the inner diameter of the anti-polishing ring is provided with a plurality of circumferential grooves or more or less fine threads. The function of a notch of this kind or of another geometry is, among other things, that it can produce a labyrinth effect. The labyrinth effect has a sealing effect known per se and thus at least significantly reduces the volumetric flow rate of the combustion gas flowing along the piston head towards the piston ring package and further into the area under the piston. This also reduces the maximum gas pressure acting on the piston ring package.

  In addition, notched grooves can be provided in either the anti-polishing ring or the piston head area, or both, to accelerate the deposition of combustion residues. The inner surface of the ring, that is, the outer diameter of the piston ring is reduced by the surface of the piston head and / or the anti-polishing ring covered with the combustion residue, and the distance between the anti-polishing ring and the piston ring, that is, the gap is reduced. The distance between the anti-polishing ring and the piston head is therefore automatically adjusted to an optimum value in the operating state according to the invention.

  For example, if the output is increased so that the outer diameter of the piston head is increased, i.e. the inner diameter of the anti-polishing ring is reduced, the combustion residue at the anti-polishing ring and / or the piston ring is relatively soft. Is scraped off by the relative movement of both, thereby automatically adjusting the optimum spacing between the anti-polishing ring / piston head, ie between the residue deposition surfaces of one or both of these components. This ensures that the optimum spacing between the anti-polishing ring / piston head is always automatically maintained independently of the operating conditions of the reciprocating engine and also regardless of the wear conditions of the relevant engine components, The optimum sealing action is also always adjusted, so that the maximum possible reduction in gas pressure on the piston ring package is adjusted.

In addition, such a reduction in the anti-polishing ring / piston head spacing significantly reduces the volumetric flow rate of the combustion gas that rubs through the piston from the combustion chamber through the piston ring package.
As already mentioned, in a particularly preferred embodiment, the scraping device, which is preferably an anti-polishing ring, is provided with a notch. In that case, the notch according to the present invention can be provided in the piston head, not in the scraping device, but may be provided in both.
This notch can be variously configured according to actual requirements. For example, it can be composed of a single section having a plurality of recesses, but these recesses are accidentally preferred, even if they are provided at the piston head or scraping device, i.e., the anti-polishing ring, according to a tissue model. May be provided according to a uniform distribution format.

In practice, in the case of a particularly important embodiment, the notch is configured in the form of a groove that circulates around the cylinder longitudinal axis and / or in the form of a spiral groove about the cylinder longitudinal axis. In that case, it goes without saying that both of these groove types can be combined and provided in the same embodiment. In that case, needless to say, it is preferable to provide a plurality of circumferential grooves.
In order to simplify the maintenance work, in particular for the cylinders and thus to save repair costs, the scraping device is attached to the cylinder wall as a removable or replaceable scraping ring.

  In that case, the removable scraping device can have a constant cross-section relative to the cylinder longitudinal axis, in other words the cross-section of the anti-polishing ring is particularly preferably rectangular. In special cases, however, it can also have a non-constant and varying cross-section, for example in accordance with the geometry of the piston head. For example, the anti-polishing ring may have a cross-sectional shape corresponding to the cross-section of the piston head, for example, a triangular shape or other suitable cross-sectional shape.

  Similarly, notches can be provided in the removable piston head ring for cost reasons, i.e. to simplify maintenance work on the engine. In other words, the piston head is fitted with a replaceable piston head ring corresponding to the anti-polishing ring and this ring is welded to the piston head, for example, fastened by a large mechanical stress, or another suitable It is fixed to the piston head by a simple form. In that case, in certain cases, it is sufficient to replace only the piston head ring instead of replacing the entire piston, which in particular reduces replacement parts and thus further costs.

In particular, the notch of the present invention has a maximum depth of 0.1 mm to 5 mm, preferably 0.5 mm to 3 mm, and in the case of, for example, a groove-shaped notch, the number of notches is 1 / cm. -15 / cm, in particular 4 / cm to 10 / cm, or in the case of planarly distributed notches, the number is 1 / cm ² to 15 / cm ² , in particular 4 / cm ² to 10 / cm ² .

The invention further relates to a piston, a removable scraping ring and a removable piston head ring having the gas pressure reducing device of the present invention, as well as a cylinder and a removable scraping ring, i.e. removable. And a piston having a simple piston head ring.
In addition, the present invention relates to a reciprocating engine, and more particularly to a two-cycle large diesel engine having a gas pressure reducing device and / or a piston and / or cylinder as detailed herein.

The particular advantage of the present invention due to the ability to use a removable scraping ring, in other words an anti-polishing ring, ie a removable piston head ring, is notably a conventional engine, in particular a large part with a very long lifetime. Diesel engines can be additionally equipped with the present invention very easily, and there is no need to make expensive changes to the engine.
In the following, the invention will be described in detail with reference to the drawings.

The figure which shows the cylinder structure provided with the anti-polishing ring of this invention. (Example 1) FIG. 1b is a diagram of the cylinder configuration of FIG. 1a with combustion residue adhering to the anti-polishing ring. The figure of the cylinder structure by this invention in which the helical groove | channel was formed in the piston head. (Example 2) FIG. 2b is a diagram of the cylinder configuration of FIG. 2a with combustion residues attached to the piston head. 1 shows a cylinder arrangement according to the invention with a removable anti-polishing ring and a removable piston head ring. FIG. (Example 3) FIG. 5 is a diagram of another preferred embodiment of the present invention. Example 4 FIG. 5 is a diagram of another preferred embodiment of the present invention. (Example 5) FIG. 5 is a diagram of another preferred embodiment of the present invention. (Example 6)

  In FIGS. 1 a to 3, a cylinder configuration having a gas pressure reducing device according to the present invention is shown by a schematic partial sectional view, respectively. The reduction device will be denoted generally by the reference numeral 1 below.

  All the embodiments shown in FIGS. 1a to 3 show a reciprocating engine known per se, apart from the reduction device 1,100 of the present invention, a two-cycle cross as a specific example in the present case. Indicates a head large diesel engine. The engine comprises a cylinder 4 in which a piston 2 is arranged, and the piston 2 comprises a piston ring package 22 consisting of three piston rings in a ring section 21. Needless to say, the number of rings of the package 22 may be more or less than three. In the figure, a gas pressure P acts on the piston ring package 22 disposed below the piston head 23 on the combustion chamber 3 side during operation. This gas pressure P is generated in the combustion chamber 3 during the compression stroke of the piston 2, that is, when the combustion mixture is ignited. The piston 2 is arranged so as to be able to reciprocate along the longitudinal axis L of the cylinder 4 in a known manner during operation, whereby the piston head 23 is a combustion residue scraping device provided on the cylinder wall 41 during movement. 5 and collaborate near top dead center OT.

According to the present invention, unlike the prior art, the reduction device 1 is configured and provided in the form of the notch 100, whereby the combustion residue adhering to the reduction device can be controlled, and the piston head 23 is at the top dead center OT. By cooperating with the scraping device 5 nearby, the gas pressure P acting on the piston ring package 22 is automatically adjusted. In this case, the scraping device 5 is an anti-polishing ring 5.
This general principle of the invention is applicable to all embodiments and is implemented in different embodiments, as shown in FIGS.

  In FIG. 1 a, the reduction device 1 according to the invention is configured in the form of a groove 100 that spirals around a longitudinal axis L. FIG. 1a shows a state before the first operation of the cylinder 4 after repair. Therefore, the combustion residue 6 does not adhere to any of the piston head 23 and the scraping device 5 provided with the spiral groove 100.

  FIG. 1b shows the state after a certain operating time of the cylinder configuration of FIG. 1a. As can be clearly seen from this figure, the combustion residue 6 is clearly attached to the removable scraping ring 5. In this case, the burnt residue 6 is formed on the ring surface facing the piston head 23 near the top dead center OT by the ring 5 cooperating with the piston head 23 during the reciprocating motion of the piston 2, thereby burning The surface of the residue 6 cooperates with the corresponding surface of the piston head 23 in a shape-connecting manner to some extent. Thereby, on the one hand, an optimum sealing effect occurs between the scraping ring 5 and the piston head. On the other hand, this optimum sealing effect is maintained even when the outer diameter of the piston head 23 and / or the inner diameter of the scraping ring 5 is changed, for example due to load fluctuations and / or temperature fluctuations. If the distance between the scraping ring 5 and the piston head 23 increases with time, for example, more combustion residue 6 adheres and the gap is closed again. On the other hand, when the interval between the piston head 23 and the scraping ring 5 is narrowed, the distance between the piston head 23 and the scraping ring 5 is narrowed by the scraping movement of the piston head 23 along the surface of the relatively soft residue attached to the scraping ring 5. Minute combustion residue is scraped off and adjusted to the optimum interval again.

  In this case, the point that can be clearly confirmed is that the seal between the piston head 23 and the scraping ring 5 is obtained even when the combustion residue 6 has not yet adhered to the reduction device 1, 100 as shown in FIG. The action is already a significant improvement over the prior art. This is because the circumferential groove 100 acts as a labyrinth seal, which already reduces the pressure on the piston ring package 22 significantly.

The embodiment of FIGS. 2a and 2b differs from the embodiment of FIGS. 1a and 1b in that the reduction device 1 according to the invention is provided not on the scraping device 5 but on the piston head 23. . In this case, the notch 100 is not in the form of a spirally circulating groove, but in the form of a notch 100 that is uniformly distributed with some difference, for example, in the form of a small recess, the piston head 23 Distributed over the surface.
For this reason, the combustion residue 6 adheres mainly to the piston head 23. The resulting sealing effect is completely similar to the embodiment of FIGS. 1a and 1b.

  FIG. 3 shows a very specific embodiment of the invention. In this embodiment, both the scraping ring 5 and the piston head 23 are provided with a reduction device 1, 100 according to the invention in the form of a notch 100. In this case, since the detachable piston head ring 7 is arranged in the piston head 23, for example, even when the reducing device 1, 100 of the piston head 3 is worn, it is not necessary to replace the entire piston 2. Instead, it is only necessary to replace the ring 7. In the case of FIG. 3, the cylinder structure has not yet been activated. Therefore, the combustion residue has not adhered yet. In the operating state, the combustion residue gradually adheres to both the piston head 23 and the scraping ring 5, and finally a shape connection type seal is formed.

  The embodiment of FIG. 3 is particularly suitable for applications where there is relatively little adhesion of combustion residues. In this case, the action of the labyrinth seal formed on both the piston head 23 and the scraping ring 5 is particularly effectively exerted twice, so that even if not much combustion residue adheres, it is compared with the prior art. Thus, the sealing effect between the piston head 23 and the scraping ring 5 is remarkably improved.

FIGS. 4a to 4c show three particularly preferred embodiments of the invention.
As described above, an important point as an advantage for the present invention is that the cross section (interval) between the cylinder 4, that is, the scraping device 5 or the reduction device 1, and the piston head 23 changes.
As can be seen particularly well from FIGS. 4a to 4c showing the cylinder at the stop temperature, the scraping device 5 or the reduction device 1, which is a component, and the piston head 23 are configured not to be parallel to each other, particularly in the cold state. Has been. In that case, the scraping-off device 5 or the reduction device 1 and the piston head 23 can be configured in any one of a spherical shape, a corrugated shape, and a stepped shape, for example.

  According to the embodiment of FIG. 4a, the piston head 23 has a conically tapered shape towards the combustion chamber and the scraping ring 5 has a shape that closes towards the combustion chamber, In another embodiment not shown, the shape can be reversed depending on the deformation tendency.

In another embodiment shown in FIG. 4b, it goes without saying that only one of the two opposing surfaces can have a varying cross section, in which case it is preferable to change the cross section of the piston head 23. .
As also already mentioned, a particular advantage of the present invention is that a surface or surface having a shaped part 100 that can be configured in the shape of a notch 100, for example a groove 100, by heating the component during operation. The non-facing surfaces oppose in an optimal manner, whereby the desired sealing effect is adjusted by the labyrinth seal of the notch 100 with or without the combustion residue 6 attached.

In that case, as can be seen in FIG. 4c, the cross section (interval) is closed towards the combustion chamber 3, and in particular when it is reduced, a good seal is obtained without the combustion residue 6. This is because the minimum cross section is located closest to the combustion chamber.
On the other hand, when the cross section opens toward the combustion chamber 3 and is particularly enlarged, the combustion residue 6 adheres rapidly, and the adhesion of this residue is based on the expected temperature rise and the expansion of the cross section.
The reduced or enlarged cross section shown in FIGS. 4 a to 4 c preferably has an angle of about 0.238 ° to 0.7 ° with respect to the normal, ie with respect to the longitudinal axis of the cylinder 4.
The embodiments of the present invention described above are to be understood as representative examples, and particularly include all appropriate combinations of the above-described embodiments.

DESCRIPTION OF SYMBOLS 1 Gas pressure reducing device 2 Piston 3 Combustion chamber 4 Cylinder 5 Scraping ring, scraping device, anti-polishing ring 6 Combustion residue 7 Piston head ring 21 Ring area 22 Ring package 23 Piston head 41 Cylinder wall 100 Notch, Groove, gas pressure reduction device (1,100)
P Gas pressure

Claims (15)

A reduction device for reducing the gas pressure (P) acting on the piston ring package (22) arranged in the ring section (21) of the piston (2) during operation of the reciprocating engine, wherein the piston (2) A piston head (23) adjacent to the ring section (21), the piston head being located on the combustion chamber side of the reciprocating engine in the assembled state, and the piston (2) in the vertical direction of the cylinder (4) in the activated state. The piston head (23) is provided on the cylinder wall (41) near the top dead center (OT) of the movement in the cylinder (4) by being arranged so as to be able to reciprocate along the axis (L). In cooperation with the scraping device (5), the combustion residue (6) is scraped off while being controlled, and the reduction device is configured in the form of a notch (100), thereby leading to the reduction device. Combustion residue of (6 In of the type deposition of is controlled,
The scraping device (5) and the piston head (23) are constructed and arranged in such a way that they are at least partly inclined with respect to each other at a presettable angle (α) at the stop temperature, whereby the piston ring The gas pressure (P) acting on the package (22) is reduced automatically and adjustable when the piston head (23) cooperates with the scraping device (5) near top dead center (OT). A gas pressure reducing device characterized by the above.   2. Reduction device according to claim 1, wherein the piston head (23) has a tapered shape towards the combustion chamber (3).   The reduction device according to claim 1 or 2, wherein the piston head (23) has a shape expanding toward the combustion chamber (3).   The reduction device according to any one of claims 1 to 3, wherein the scraping device (5) has a tapered shape toward the combustion chamber (3).   The reduction device according to any one of claims 1 to 4, wherein the scraping device (5) has a shape expanding toward the combustion chamber (3).   The reduction device according to any one of claims 1 to 5, wherein the notch (100) is provided in a scraping device (5).   The reduction device according to any one of claims 1 to 6, wherein the notch (100) is provided in a piston head (23).   The notch (100) is configured in the form of a groove (100) that circulates around a longitudinal axis, in particular in the form of a groove (100) that circulates in a helical manner around the longitudinal axis (L). The reduction device according to claim 7.   The reduction device according to any one of claims 1 to 8, wherein the circulating groove (100) is plural.   10. Reduction device according to any one of the preceding claims, wherein the scraping device (5) is provided on the cylinder wall (41) as a removable scraping ring (5).   11. Reduction device according to any one of the preceding claims, wherein the notch (100) is provided in a removable piston head ring.   A piston comprising a reduction device (1,100) according to any one of the preceding claims.   A removable scraping ring comprising a reduction device (1,100) according to any one of the preceding claims.   A cylinder with a removable scraping ring (5) according to claim 13.   A reciprocating engine having a reduction device (1,100) according to any one of claims 1 to 11 and / or a piston according to claim 12 and / or a cylinder according to claim 14, in particular 2 Cycle large diesel engine.

Images