AT521272B1 - METHOD FOR OPERATING A COMBUSTION GAS COMBUSTION ENGINE - Google Patents

Abstract

The invention relates to a method for operating a combustion gas (15) internal combustion engine, in particular a large internal combustion engine with at least one cylinder (1), with at least one piston (2) with at least one piston ring (14) in the cylinder having a cylinder wall (10) (1) moved from a bottom dead center to a top dead center and the fuel gas (15) is blown into at least one piston position in the region of the cylinder wall (10). The object of the invention is to provide an internal combustion engine and a method for operating an internal combustion engine which reduces the accumulation of the fuel gas in the gap between the piston and the cylinder. This is achieved in that a cleaning gas is blown into the cylinder (1) through at least one cleaning opening (9, 9a, 9b) arranged on the cylinder wall (10) when at least one cleaning opening (9, 9a, 9b) from the top land (28 ) of the piston (2) is at least partially covered.

Description

Austrian patent office

Description: The invention relates to a method for operating a combustion gas-burning internal combustion engine, in particular a large-scale internal combustion engine with at least one cylinder, wherein at least one piston with at least one piston ring moves in the cylinder having a cylinder wall from a bottom dead center to a top dead center and thereby the fuel gas is blown in at least one piston position in the region of the cylinder wall and a cleaning gas is blown into the cylinder through at least one cleaning opening arranged on the cylinder wall if at least one cleaning opening is at least partially covered by the top land of the piston.

The invention also relates to an internal combustion engine which can be operated with fuel gas, in particular a large internal combustion engine with at least one cylinder having a cylinder wall and at least one piston arranged therein, the fuel gas being inflatable in the region of the cylinder wall and the piston having at least one piston ring and either the cylinder wall has at least one cleaning opening for introducing cleaning gas and at least one injection opening for blowing in the fuel gas, in which case at least one cleaning opening is arranged in a region above 2% below at least one injection opening, based on the piston stroke (H), or the cylinder wall has at least one cleaning opening through which both the cleaning gas and the fuel gas are blown.

In the case of internal combustion engines which can be operated with fuel gas, a fuel gas inlet is often provided in the region of the cylinder wall for good distribution of the fuel gas. The introduction usually takes place via an injection opening or injection device arranged on the cylinder wall, as shown in EP 2 868 890 A1. The fuel gas is injected while the piston is moving upwards. The piston generally has a piston roof facing the combustion chamber and a piston jacket. At least one piston ring, which is arranged on the piston skirt, seals the combustion chamber from the crank chamber. This prevents the penetration of fuel gas into the crank chamber and seals the combustion chamber from the crank chamber despite an existing gap between the piston skirt and the cylinder. Such gaps can be, for example, 3 mm wide, in particular in large internal combustion engines, such as those used for ships. As a result, the combustion chamber not only extends above the piston roof, but into the gap up to the upper edge of the top piston ring.

Internal combustion engines of this type often have the problem that fuel gas accumulates in relevant amounts in the area of the top land - this is the jacket area of the piston between the piston roof and the uppermost piston ring - in the gap up to the piston ring. This can lead to incomplete and uncontrolled combustion (knocking), increased fuel consumption, reduced performance and increased wear of the parts.

[0005] JP 201254189 A and JP 2012154188 A disclose internal combustion engines which have nozzles arranged on the cylinder jacket for injecting a cleaning gas in order to clean the gap between the cylinder and piston of fuel gas. This reduces the negative effects mentioned above, but there is still a high level of material wear.

The object of the invention is to provide an internal combustion engine and a method for operating an internal combustion engine, which reduces material wear.

This object is achieved in that cleaning gas in the amount of at least 1% of a total loading mass of the cylinder is blown through the at least one cleaning opening per working cycle.

It is also solved in that the cleaning opening is set up to blow in cleaning gas per working cycle in the amount of at least 1% of a total loading mass of the cylinder.

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AT 521 272 B1 2019-12-15 Austrian Patent Office [0009] In embodiments with more than one cleaning opening and / or more than one blowing opening, it is essential that at least one cleaning opening is above 2% below at least one blowing opening, based on the piston stroke , This arrangement ensures adequate cleaning of the gap. Embodiments are also conceivable in which at least one cleaning opening can lead to cleaning gas and also also fuel gas, but additionally injection openings are also provided. Of course, cleaning openings that only blow in cleaning gas can also be combined with those that can also blow in fuel gas. The cleaning opening is understood to mean an opening which is supplied with cleaning gas, preferably fresh air or a non-combustible gas such as nitrogen or carbon dioxide. This cleaning gas is usually compressed beforehand. The cleaning opening can be designed as a bore in the cylinder or as an inlet device, for example as an inlet nozzle. It is preferably arranged between the cylinder head and the bottom dead center of the piston.

Covered is understood to mean that the piston roof is located above the cleaning opening and is therefore covered by the piston skirt, in particular by the top land of the piston. This means above in the direction of the top dead center of the piston.

“On the cylinder wall” or “in the region of the cylinder wall” is understood to mean that the opening through which fuel gas is blown is either arranged in the cylinder wall, or it is arranged in the cylinder ceiling and directed towards the cylinder wall.

The piston stroke is the maximum path of the piston along the cylinder axis in one direction and extends from an upper dead center to a lower dead center of the piston. Dead points mean those points in the movement of the piston in which the piston changes its direction of movement. The dead centers thus describe the maximum way points of the piston along its upward and downward movement in the cylinder.

These measures allow cleaning gas to be introduced into the gap between the cylinder and the top land. The inflowing cleaning gas displaces the fuel gas-air mixture located there, which is pressed in the direction of the top dead center of the piston or the cylinder head, if present. A gas cushion with little fuel gas can form in the area of the piston roof and the gap. This reduces the risk of incomplete and uncontrolled combustion, reduces fuel consumption and improves performance.

The cleaning gas injection can only begin when the cleaning opening is completely covered by the top land or before. It can be interrupted in places while the piston is moving past, the amount of cleaning gas or the pressure of the introduced cleaning gas can be varied.

In order that a particularly low fuel gas layer is achieved in the area of the piston roof, it can be provided that the cleaning gas injection begins through at least one cleaning opening before the cleaning opening is at least partially covered by the top land of the piston.

Furthermore, it can be provided that the cleaning gas injection is ended when the uppermost piston ring moves past at least one cleaning opening. If there are several cleaning openings at different heights, the cleaning gas injection is particularly preferably ended when the uppermost piston ring moves past the uppermost cleaning opening. The uppermost piston ring means the piston ring that is closest to the piston roof and thus to the combustion chamber. This prevents the cleaning gas from flowing into the crank chamber from the cleaning opening. Moving past is understood to mean that the top edge of the top piston ring passes the top edge of the cleaning opening, that is to say the connection between the combustion chamber - which is delimited by the top piston ring - and the cleaning opening is interrupted. From the point at which the top edge of the piston ring and the top edge of the cleaning opening are on the same

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There is no longer any gas exchange between the cleaning opening and the combustion chamber. Alternatively, the cleaning injection can also be ended sooner or later. It can even be continued if the piston has already moved up so far that the cleaning opening is no longer covered by the piston jacket. In this case, the cleaning gas would be blown into the crankcase.

It is also advantageous that cleaning gas in the amount of at least 1%, preferably between 1% and 3% of a total loading mass of the cylinder is blown in via the at least one cleaning opening per working cycle. By blowing this minimum mass of cleaning gas into the cylinder it is achieved that the fuel gas / air mixture contains particularly little fuel gas in the area of the gap. The total loading mass of the cylinder is understood to mean that mass which is introduced into the cylinder for a combustion process during a working cycle. This usually consists mainly of fuel gas, exhaust gas, fresh air, cleaning gas and possibly other added gases.

It is also advantageous if the fuel gas injection is ended at or after the start of the cleaning gas injection. As a result, the fuel gas distribution in the combustion chamber can be influenced and, if necessary, a gradient of the fuel gas concentration along the cylinder axis can be achieved.

The fuel gas injection can take place in different ways. Provision can be made for the fuel gas to be blown in via at least one cleaning opening in addition to the cleaning gas, or for the fuel gas to be blown in via at least one cleaning opening. The desired effect can thus be achieved with only one opening in the cylinder, since the cleaning opening carries both cleaning gas and fuel gas. The cleaning opening can be connected, for example, via valves to a line or channel carrying cleaning gas and to a line carrying fuel gas, which open and close depending on the piston position and cycle step. The open intervals can at least partially overlap. It is particularly advantageous if the valves are arranged as close as possible to the cleaning opening so that no residual air or residual gas remains in the area between the valves and the cleaning opening.

Alternatively, the fuel gas injection cannot take place via the cleaning opening. For example, it can be provided that the cylinder wall has, in addition to the cleaning opening, at least one blowing opening for blowing in the fuel gas. Like the cleaning opening, this can be designed as a nozzle or as a differently designed injection device and can provide valves as described above for controlling the fuel gas injection.

It can be provided that the cleaning gas injection takes place in the height range of the fuel gas injection. It is also advantageous if at least one cleaning opening is at the same cylinder height with at least one blowing opening.

[0022] The height range relates to the cylinder axis of the cylinder or the parallel axis of movement of the piston. The cleaning opening and the fuel gas injection can be at the same height or can be offset in height from one another and can preferably be closely related to one another along the cylinder axis or movement axis.

In a preferred embodiment it is provided that the cleaning gas injection takes place in a range above 2% below the location of the fuel gas injection, based on the piston stroke. This ensures that the gap is sufficiently cleaned of fuel gas.

The cleaning injection, or the arrangement of the cleaning opening can be arranged above the location of the fuel gas injection, or the injection opening, but it should not be arranged above the top dead center of the piston, since otherwise the gap is poor or not at all Can free fuel gas.

[0025] The higher the cleaning opening is arranged in the cylinder, the more pressure is required

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AT 521 272 B1 2019-12-15 Austrian patent office have the injected cleaning gas so that it can be injected in sufficient quantities. It is therefore advantageous if the cleaning opening is arranged in the lower or middle third of the piston stroke.

The problem of high pressure also applies to the fuel gas injection. Accordingly, it is advantageous if this takes place in the lower half, particularly preferably in the lower third of the piston stroke, but above the flushing channel.

The cleaning opening and the injection opening can be at a certain angle to one another in the cylinder cross section, or preferably be diametrically opposed. They can also be arranged directly above one another at different heights. Embodiments with one or more cleaning openings and at least one blowing opening are also possible, at least one cleaning opening carrying both cleaning gas and fuel gas or only cleaning gas.

It is preferably provided that the internal combustion engine has at least one injection device for a liquid fuel. This means that the internal combustion engine can be operated not only with fuel gas, but also with liquid fuel such as heavy oil. These are usually located at the end of the cylinder opposite the crank chamber, ie the combustion chamber ceiling, and are designed in the form of an injector.

Furthermore, it can be provided that the cylinder has at least one flushing opening for supplying combustion air, which is arranged between the at least one cleaning opening and the bottom dead center of the cylinder. As a result, the combustion chamber can be flushed with cleaning gas, preferably from the crank chamber, after combustion and downward movement of the piston. On the one hand, the exhaust gas can be removed from an exhaust gas opening arranged opposite the crankcase, and on the other hand fresh air can be provided for the next combustion process.

It is particularly advantageous if at least one cleaning opening has a diameter of at least 10 mm, preferably at least 15 mm. As a result, sufficient cleaning gas quantities can be made available for cleaning even for large internal combustion engines.

It is also advantageous if the internal combustion engine is operated as a two-stroke engine. Accordingly, it is also advantageous if the internal combustion engine is a two-stroke engine. The two cycles result in a circular cycle (360 ° crankshaft revolution of the crankshaft of the piston), which means that the engine only completes two cycles per work cycle, namely within only one upward and downward movement of the piston.

In the following, the present invention is explained in more detail with reference to the non-restrictive embodiment variants according to the invention shown in the figures. Show it:

1a to 1d a pair of cylinders and pistons of a first embodiment of an internal combustion engine according to the invention in schematic sectional views in different piston positions; Figure 2 a cross section of a cylinder in a second embodiment in a schematic view; Fig. 3 a cylinder-piston pair in a third embodiment in a schematic, sectional view; Fig. 4 Fig. 5 Fig. 6 an opening diagram of a fourth embodiment; an opening diagram of a fifth embodiment; a detail of the first embodiment shown in Fig. 1a to 1d in a schematic section.

1a, 1b, 1c and 1d show a cylinder 1 with a piston 2 arranged therein. The cylinder 1 extends from a lower end 4 to a crank chamber 3 to

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AT 521 272 B1 2019-12-15 Austrian patent office to an opposite upper end 5 along a cylinder axis A. At the upper end 5 there is an exhaust opening which can be closed with an exhaust valve 6 and which leads to an exhaust duct 7. In the central area between the ends 4, 5 and approximately at half the height of a piston stroke H of the piston 2, an injection opening 8 is arranged on a cylindrical cylinder wall 10 and is supplied with fuel gas which serves as fuel for combustion. At the level of the blowing opening 8 there is a cleaning opening 9, which is arranged in the cross section of the cylinder 1 at the level of the blowing opening 8 and opposite it. For example, it is only supplied with compressed air as the cleaning gas. As a result, the fuel gas injection and the cleaning gas injection take place through different openings. A gap 13 is formed between the piston 2 and the cylinder wall 11 of the cylinder 1. This is sealed by a piston ring 14 in the upper region of the piston 2 and thus a combustion chamber 30 between the upper end 5 and the piston ring 14 is closed. The top land 28 is located as part of the piston skirt 33 between a piston roof 12 and the piston ring 14.

In Fig. 1a, the piston 2 described is in its bottom dead center and at the lower end 4 of the cylinder 1. The exhaust valve 6 is open. Air can penetrate into the cylinder 1 from the crank chamber 3 through flushing openings 11 in the cylinder wall 10, since the piston 2 is located below the latter. The inflowing air is distributed in the cylinder and the exhaust gas flows through the exhaust gas opening into the exhaust gas channel 7. The gas-carrying channels connected to the injection opening 8 and the cleaning opening 9 are closed by valves.

Fig. 1b shows a subsequent piston position, at an advanced crank angle of the crankshaft of the piston 2, which moves in the direction of the upper end 5, but is still below the injection opening 8 and the cleaning opening 9. However, the flushing openings 11 are already closed by the piston 2 and are no longer connected to the shrinking combustion chamber 30. The exhaust valve 6 is still open and the valve of the channel of the injection opening 8 opens. As a result, fuel gas 15 is blown into the cylinder 2. The valve of the cleaning opening 9 remains closed.

1c shows a position following FIG. 1b, in which the piston roof 12 of the piston 2 is located directly below the injection opening 8 or the cleaning opening 9 and these are still free. The exhaust valve 6 is closed and prevents the fuel gas-air mixture from escaping. As a result, the pressure in the cylinder 1 increases with increasing upward movement of the piston 2. The fuel gas injection through the injection opening 8 is ended and the valve of the channel of the cleaning opening 9 is opened, as a result of which air flows into the cylinder 2 as the cleaning gas. The injected fuel gas 15 is thus driven in the direction of the upper end 5 and a cleaning gas cushion low in fuel gas is generated on the piston roof 12.

In Fig. 1d, the piston 2 has already moved so far that a piston roof 12 of the piston 2, and the piston ring 14 is located above the injection opening 8 and the cleaning opening 9 and thus between them and the upper end 5, or an upper dead center of the piston 2. The cleaning gas injection through the cleaning opening 9 which has continued until then has largely freed the gap 13 of fuel gas 15 and is ended by closing the valve of the channel of the cleaning opening 9. After this position, the piston 2 continues its upward movement until it reaches top dead center, where the compressed gas mixture is burned (not shown).

2 shows an embodiment with a plurality of cleaning openings 9 and injection openings 8. In this case, two first cleaning openings 9a lying opposite one another in the cross section of the cylinder 2 have connections to a channel 16 carrying fuel gas and one channel 17 carrying cleaning gas each, while a second cleaning opening 9b is only connected to one channel 17 carrying cleaning gas. In addition, an injection opening 8 is provided which is only connected to a channel 16 carrying fuel gas. The second cleaning opening 9b, which is only connected to a cleaning gas-carrying channel 17, is arranged in cross section normal to the first cleaning openings 9a. The fuel gas carriers

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Channels 16 are arranged essentially radially to the cylinder 1, while the channels 17 carrying the cleaning gas converge with the channels 16 carrying the fuel gas and the first cleaning openings 9a at an acute angle in the normal plane to the cylinder axis A. This will blow in the air at an angle. The injection opening 8 is arranged between a first cleaning opening 9a and the second cleaning opening 9b and is essentially at a 45 ° angle between the adjacent openings 9a, 9b. The cleaning gas-carrying channel 17 of the second cleaning opening 9b likewise opens radially to the cylinder 1 into the second cleaning opening 9b, as a result of which this air is blown in radially. The fuel gas channel 16 of the injection opening 8, on the other hand, opens eccentrically and thus introduces the fuel gas 15 into the cylinder 1 at an angle. As a result, the fuel gas is injected through the first cleaning openings 9a and the injection opening 8, while the cleaning gas is injected via the first cleaning openings 9a and the second cleaning openings 9b.

Fig. 3 shows a third embodiment similar to the first embodiment with a plurality of first cleaning openings 9a and injection openings 8. All openings 9a, 8 are arranged in the lower half of the piston stroke H. In this case, two first cleaning openings 9a, which are each connected to a channel 16 carrying fuel gas and a channel 17 carrying cleaning gas, are arranged offset in height from one another along the cylinder axis A. At the level of the lower, first cleaning opening 9a and below this, there is one blowing opening 8 each. Here, the cleaning gas-carrying channel 17 is at the first cleaning openings 9a in the region of the confluence once with respect to the cylinder axis A and once normal. The same applies to the channels 16 carrying fuel gas, but to the other first cleaning openings 9a.

The first cleaning openings 9a and the injection openings 8 are thus distributed along the cylinder axis A, being distributed over less than half the cylinder length and the piston stroke. They are located in the lower two thirds of the cylinder, spaced from the bottom dead center of the piston.

FIG. 4 shows a possible opening diagram according to the invention of the openings in an embodiment of an internal combustion engine according to the invention which uses a method according to the invention. These openings and closings are achieved by valves which define the fuel gas injection, exhaust gas discharge and cleaning gas injection, or by covering the purge openings 11 by the piston 2 and are represented as a function of the crank angle 19 of the crankshaft of the piston 2. A degree of opening 18 of 1 means that the valve is completely open, or that the purge openings are completely free, whereby a complete flow of the fuel gas, exhaust gas or cleaning gas is possible through the respective opening. A value of 0 represents the complete closure, which means that no flow is possible. In addition, the cylinder pressure 20 is shown as a curve 22 as a function of the crank angle 19.

Line 21 shows the degree of opening of the outlet opening of the outlet valve 6, which is fully open at a low crank angle 19, that is when the piston 2 is near its bottom dead center. The exhaust gas resulting from the last combustion can leave the cylinder 2 through the exhaust gas duct 7. At a crank angle of 230, the piston 2 begins to cover the flushing openings 11 due to its upward movement, as a result of which the flow of cleaning gas from the crank chamber rapidly decreases through these (line 23). At the same time as the purging openings 11 begin to close, the valves of the fuel gas ducts 16 of injection openings 8 and cleaning openings 9 are opened and fuel gas flows into the cylinder 2 (line 24). The valves need a crank angle of about 5 ° to open fully. At a crank angle of 265 °, just before the piston roof 12 reaches the openings through which the fuel gas is injected, they begin to close again, which is completed at about 270 °.

At a crank angle of 240 °, the exhaust valve 6 begins to close, it being fully closed at 290 °. The cylinder pressure, which had remained largely the same up to that point, rises continuously as the exhaust valve 6 progressively closes.

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AT 521 272 B1 2019-12-15 Austrian Patent Office [0050] With a crank angle of 260 °, that is to say while the fuel gas is being blown in, the valves of the channels 17 of the cleaning openings 9 carrying cleaning gas are opened (line 25), and cleaning gas is blown in. This opens more slowly and its full opening is only reached at a crank angle of 270 °, i.e. when the fuel gas injection has been completed. This achieves a cleaning gas cushion in the area of the piston roof 12, which is particularly low in fuel gas directly above the piston roof 12. Due to the early cleaning gas injection, the cleaning gas can be introduced at a relatively low cylinder pressure, which means that it does not have to be compressed as much.

At a crank angle of 280 °, the piston roof 12 reaches the cleaning openings 9, indicated by flank 26. From this point, the top land 28 begins to cover the cleaning openings 9, as a result of which the cleaning gas flows into the gap 13 and cleans it of fuel gas. At a crank angle of 290 °, the upper edge of the piston ring 14 reaches the upper edge of the cleaning openings 9, indicated by flank 27. Shortly before, at 286 °, the valves of the channels 17 carrying cleaning gas begin to close, and reach at 295 ° shortly after the piston ring 14 the cleaning openings 9 passes its full closed position.

Fig. 5 shows an opening diagram similar to that of Fig. 4. However, here the cleaning gas injection (line 25) begins only from a crank angle of 270 °, that is, after completion of the fuel gas injection (line 24). It also has a steeper climb and reaches its maximum at 275 °. In addition, the cleaning gas injection is ended before flank 27 and thus before the cleaning opening is completely separated from the combustion chamber. At 287 °, the valves of the cleaning gas-carrying channels 17 are completely closed. This means that the total amount of cleaning gas blown in is smaller and the cleaning gas cushion is smaller.

Fig. 6 shows schematically a detail of the embodiment shown in Fig. 1a-1d in a piston position between Fig. 1c and 1d. The piston 2 has on its jacket 33 a recess in which a piston ring 14 is arranged. This piston ring 14 extends across the gap 13 between the piston skirt 33 and the cylinder wall 10 and thus seals the combustion chamber 30 against the crank chamber 3. The piston 2 has a piston roof 12 which has a piston recess in the middle of the piston 2. The upper edge 32 of the piston ring 14 of the piston ring is located at the level of the upper edge 31 of the cleaning opening 9. The cleaning opening 9 is thus completely covered by the combustion chamber 30 and is therefore no longer connected to it. The piston ring 14 has approximately the same thickness as the cleaning opening 9. It is advantageous if the cleaning gas injection is ended through the cleaning opening 9 shown in the piston position shown, since cleaning gas can no longer be blown into the combustion chamber 30.

Claims (15)

1. Method for operating a combustion gas (15) internal combustion engine, in particular a large internal combustion engine with at least one cylinder (1), with at least one piston (2) with at least one piston ring (14) in the cylinder (1) having a cylinder wall (10) ) is moved from a bottom dead center to a top dead center and the fuel gas (15) is blown into at least one piston position in the area of the cylinder wall (10) and a cleaning gas is passed through at least one cleaning opening (9, 9a,) on the cylinder wall (10). 9b) is blown into the cylinder (1) if at least one cleaning opening (9, 9a, 9b) is at least partially covered by the top land (28) of the piston (2), characterized in that cleaning gas in the amount of at least 1 % of a total loading mass of the cylinder (2) through which at least one cleaning opening (9, 9a, 9b) is blown. 2. The method according to claim 1, characterized in that the cleaning gas injection through at least one cleaning opening (9, 9a, 9b) begins before this cleaning opening (9, 9a, 9b) is at least partially covered by the top land (28) of the piston (2) , 3. The method according to claim 1 or 2, characterized in that the cleaning gas injection is stopped when the uppermost piston ring (14) moves past at least one cleaning opening (9, 9a, 9b). 4. The method according to any one of claims 1 to 3, characterized in that between 1% and 3% of the total loading mass of the cylinder (2) is blown in via the at least one cleaning opening (9, 9a, 9b). 5. The method according to any one of claims 1 to 4, characterized in that the fuel gas injection is terminated at or after the start of the cleaning gas injection. 6. The method according to any one of claims 1 to 5, characterized in that the cleaning gas injection takes place in the height range of the fuel gas injection. 7. The method according to any one of claims 1 to 6, characterized in that the fuel gas (15) is blown in addition to the cleaning gas via at least one cleaning opening (9, 9a, 9b). 8. The method according to any one of claims 1 to 7, characterized in that the cleaning gas injection takes place in a range above 2% below the location of the fuel gas injection, based on the piston stroke (H). 9. The method according to any one of claims 1 to 8, characterized in that the internal combustion engine is operated as a two-stroke engine. 10. Internal combustion engine that can be operated with fuel gas (15), in particular a large internal combustion engine with at least one cylinder (1) having a cylinder wall (10) and at least one piston (2) arranged therein, the fuel gas (15) in the region of the cylinder wall ( 10) is inflatable, the piston (2) having at least one piston ring (14) and either the cylinder wall (10) having at least one cleaning opening (9, 9a, 9b) for introducing cleaning gas and at least one blowing opening (8) for blowing in the Combustion gas (15), in which case at least one cleaning opening (9, 9a, 9b) is arranged in an area above 2% below at least one blowing opening, based on the piston stroke (H), or the cylinder wall (10) has at least one cleaning opening ( 9, 9a, 9b), through which both the cleaning gas and the fuel gas (15) are blown in, characterized in that the cleaning opening (9, 9a, 9b) is set up for each ar blowing cycle cleaning gas in the amount of at least 1% of a total loading mass of the cylinder (2). 11. Internal combustion engine according to claim 10, characterized in that at least one cleaning opening (9, 9a, 9b) lies at the same cylinder height with at least one injection opening (8). 8.15 AT 521 272 B1 2019-12-15 Austrian patent office 12. Internal combustion engine according to claim 10 or 11, characterized in that the internal combustion engine has at least one injection device for a liquid fuel. 13. Internal combustion engine according to one of claims 10 to 12, characterized in that the cylinder (1) has at least one flushing opening (11) for ventilation of the cylinder (1), which between the at least one cleaning opening (9, 9a, 9b) and bottom dead center of the cylinder (1) is arranged. 14. Internal combustion engine according to one of claims 10 to 13, characterized in that at least one cleaning opening (9, 9a, 9b) has a diameter of at least 10 mm, preferably at least 15 mm. 15. Internal combustion engine according to one of claims 10 to 14, characterized in that the internal combustion engine is a two-stroke engine.