KR20210005520A - Large two-stroke uniflow scavenged gaseous fueled engine - Google Patents

Abstract

Provided is a large two-stroke turbocharged single flow scavenging internal combustion engine using gaseous fuel as the main fuel and having one or more combustion chambers divided by a cylinder liner (1), a piston (10) and a cylinder cover (22). According to the present invention, the piston (10) is arranged to reciprocate between top dead center (TDC) and bottom dead center (BDC) so that the resulting geometric compression ratio is greater than 20. The engine is configured to introduce a first amount of pressurized gaseous fuel into the one or more combustion chambers during a stroke of the piston (10) from the BDC to the TDC, such that the fuel and air in the combustion chambers mix such that the air-fuel ratio is greater than 50. The engine is configured to inject a second amount of high-pressure gaseous fuel into the one or more combustion chambers when the piston (10) is at or near the TDC.

Description

Large two-stroke single-flow scavenging gas fuel engine {LARGE TWO-STROKE UNIFLOW SCAVENGED GASEOUS FUELED ENGINE}

The present invention relates to a large two-stroke gaseous fuel internal combustion engine, in particular a large two-stroke single-flow scavenging internal combustion engine having a crosshead operating primarily in a gaseous fuel operating mode.

A large two-stroke turbocharged single-flow scavenging internal combustion engine with a crosshead is used as a propulsion system of a large marine vessel or a prime mover of a power plant. The two-stroke diesel engine is configured differently from other internal combustion engines because of its enormous size.

Such large two-stroke turbocharged single-flow scavenging internal combustion engines increasingly use gaseous fuels such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG) instead of, for example, marine diesel oil or heavy oil. This change to gaseous fuel is driven primarily by the need to reduce emissions and provide more environmentally friendly prime movers.

The development of gaseous fuel has resulted in the development of two different types of large two-stroke turbocharged internal combustion engines that use gaseous fuel as their primary fuel.

The first type of engine is a direct injection type in which gaseous fuel is injected at high pressure around top dead center (TDC) and ignited by compression (by high temperature due to compression), and these engines are operated according to a diesel cycle. The gaseous fuel is ignited at the moment it is injected into the combustion chamber, and there is no concern related to early ignition due to a low excess air rate or misfire due to a high excess air rate. The effective compression ratio of the gaseous fuel operated large two-stroke turbocharged internal combustion engine of the first type is equal to or higher than that of a conventional liquid fuel operated large two-stroke turbocharged internal combustion engine. Typically, the effective compression ratio for this type of engine is approximately 15 to 17, while the geometric compression ratio is approximately 30. The advantage of the type 1 engine is that it is very fuel efficient due to its high compression ratio. Another advantage is that there is much less risk of pre-ignition and misfire compared to engines of the second type.

However, in order to be able to inject gaseous fuel at or near the TDC, the pressure of the gaseous fuel supplied to the fuel valve that injects the gaseous fuel into the combustion chamber must be significantly higher than the compression pressure in the combustion chamber. In practice, the gaseous fuel must be injected into the combustion chamber at a pressure of at least 250 bar, preferably at least 300 bar. The pump or pumping station increases the pressure of the liquefied gaseous fuel to, for example, 300 bar, then the high-pressure liquefied fuel is vaporized in the high-pressure evaporation unit and delivered in gaseous form to the fuel injection valve of the main engine at high pressure. This supply system is expensive compared to the conventional liquid fuel supply system.

Gaseous fuels such as natural gas have very low energy density compared to conventional fuels. To use it as a convenient energy source, it must be denser. This is accomplished by cooling the gaseous fuel to cryogenic temperatures to produce natural gas, for example liquefied natural gas (LNG) consisting mainly of methane.

The gaseous fuel supply system for such a gas-operated engine includes an insulated tank in which liquefied gas is stored to maintain a liquid state for a long period of time. However, the heat flux generated in the surrounding environment raises the temperature inside the tank and vaporizes the liquefied gas. The gas emitted from this process is called boil-off gas (BOG). Evaporation in the tank causes a significant steady flow of the gaseous fuel, which must be removed from the tank and treated. 18 10 000 m ³ to be the amount per hour of the BOG tone, generally must be processed in the LNG carrier is at about 3000kg /, gas power demand for this type LNG ships main engine is about 4000kg / poem (all energy is essentially natural of the main engine Gas).

It is technically very difficult to increase the pressure of this boil-off gas to an injection pressure of about 300 bar using a compressor, so BOG cannot be used as fuel for a large two-stroke turbocharged internal combustion engine with high pressure gas injection of the first type.

A compressor can be used to increase the pressure of the BOG to, for example, 10 to 20 bar, and for applications that can operate on gaseous fuel at this pressure, for example, generator sets related to large two-stroke turbocharged internal combustion engines generally installed on ships. (The generator set is a four-stroke internal combustion engine that is considerably smaller than a large two-stroke turbocharged internal combustion engine, and the generator set is used to drive the generator/alternator for marine power and heat production).

Alternatively, the boil-off gas may be liquefied again, for example with a cryogenic generator. However, reliquefaction requires expensive equipment and consumes a significant amount of energy.

As a final emergency, you can just burn the boil-off gas.

WO2016058611A1 discloses a large two-stroke turbocharged single-flow scavenging internal combustion engine of the first type.

No. DK201670361A1 discloses a gas supply system that delivers high-pressure gaseous fuel for high-pressure injection into a combustion chamber with a large two-stroke turbocharged single-flow scavenging internal combustion engine of the first type.

The second type of engine is a so-called low pressure gas engine in which gaseous fuel is mixed with scavenging air, and this second type of engine compresses a mixture of gaseous fuel and scavenging in a combustion chamber. In this second type of engine, gaseous fuel is introduced by a fuel valve disposed inwardly along the length of the cylinder liner. That is, it starts long before the exhaust valve is closed and flows from the bottom dead center (BDC) to the top dead center (TDC) during the upward stroke of the piston. The piston compresses the gaseous fuel and the desired mixture in the combustion chamber, and ignites the compressed mixture at or near top dead center (TDC) with a timing ignition means such as pilot oil injection. The advantage of this type 2 engine is that it can operate on gaseous fuel supplied at relatively low pressures (eg 15 bar). This is because the pressure in the combustion chamber is relatively low when gaseous fuel is introduced. Thus, an engine of the second type can be operated with an increased pressure BOG using a compressor station. Accordingly, a gas supply system for an engine of the second type may be cheaper than a gas supply system required for an engine of the first type. In particular, gas supply systems for engines of type 1 must be able to process the BOG stream produced by the tank, but boilers and generator sets can only process a portion of this BOG stream, so relatively expensive liquefaction systems are of type 1 It must be installed and operated in the gaseous fuel supply system of the engine.

However, due to the fact that engines of the second type compress the mixture in the combustion chamber, they need to operate with a significantly lower effective compression ratio compared to engines of the first type. In general, engines of the first type operate with an effective compression ratio of about 15 to about 17, while engines of the second type operate with an effective compression ratio of about 7 to about 9, and the geometric compression ratio of engines of the second type is generally It is approximately 13.5. If the geometrically determined compression ratio is significantly lower, the energy efficiency of the engine of the second type compared to the engine of the first type is significantly lower, and also the lower maximum for the engine of the second type compared to the engine of the similar size. It results in continuous rated output.

In addition, engines of the second type generally require a pre-chamber and a timed ignition system to provide stable ignition.

Other drawbacks of type 2 engines are (locally) the pistons to avoid premature ignition due to too low excess air and/or too high bulk temperatures and avoid misfires due to too high excess air and/or too low bulk temperatures. During the upstroke, the excess air rate and bulk temperature in the combustion chamber must be controlled very accurately. Proper mixing to produce a homogeneous mixture is important to avoid local conditions that could cause premature ignition or misfire in the combustion chamber. Controlling these conditions in the combustion chamber is particularly difficult in transient operation.

No. DK201770703 discloses a large two-stroke turbocharged single-flow scavenging internal combustion engine including the second type.

As a result, there is a need for a large two-stroke turbocharged single-flow scavenging internal combustion engine capable of operating on gaseous fuel as the primary fuel that overcomes or at least reduces the disadvantages of the aforementioned first and second type engines.

In addition, gas to a large two-stroke turbocharged single-flow scavenging internal combustion engine providing gaseous fuel at a pressure that can be used for combustion of a large two-stroke turbocharged single-flow scavenging internal combustion engine that overcomes or at least reduces the drawbacks of the gas supply system described above There is a need for a gas supply system to supply fuel.

Patent Document 1: WO 2016058611A1 Patent Document 2: DK 201670361A1 Patent Document 3: DK No. 201770703

It is an object to provide an engine and gaseous fuel supply system as well as a method of overcoming or at least reducing the aforementioned problems.

Objects other than those described above are achieved by the features of the independent claim. Additional implementation forms are apparent from the dependent claims, detailed description and drawings.

According to a first aspect, there is provided a large two-stroke turbocharged single-flow scavenging internal combustion engine having at least one combustion chamber divided into a cylinder liner, a piston and a cylinder cover,

The pistons are arranged to reciprocate between BDC and TDC with a geometric compression ratio greater than 20, the engine is configured to run gaseous fuel as the main fuel in at least one mode of operation, and the engine also performs at least one of the following modes of operation: Consists of

Introducing a first amount of pressurized gaseous fuel into at least one combustion chamber during a piston stroke from BDC to TDC to obtain a mixture of air and fuel having an air-fuel ratio of 50 or more by mixing with the scavenging air introduced into the combustion chamber; And

Injecting a second amount of high pressure gaseous fuel into at least one combustion chamber when the piston is at or near the TDC.

Excess air in the combustion chamber in the compression stroke by providing the engine with a large two-stroke turbocharged single-flow scavenging internal combustion engine configured to inject high-pressure gaseous fuel into or near the TDC while allowing medium pressure gaseous fuel during the compression stroke. Can be held above 50 (i.e. mass air/mass fuel (eg NLG or methane)). This minimizes the risk of pre-ignition during the compression stroke and avoids the need for very precise control of the excess air rate and bulk temperature. In addition, injection of high-pressure gaseous fuel at or near the TDC has the effect of ensuring ignition and thus avoiding misfire despite high air excess rates during the compression stroke. In addition, the robustness against early ignition allows for a much higher effective compression ratio, i.e. greater than 20, compared to engines known for the second type engine, giving the engine according to the first aspect a significantly higher fuel efficiency than the second type engine. to provide. Moreover, the prechamber generally required for engines of the second type can be avoided in the engine according to the first aspect. In addition, the performance of the engine according to the first aspect is the reliquefaction of the boil-off gas compared to the engine of the first type by consuming a significant amount of medium pressure gaseous fuel, i.e. a significant amount of fuel readily obtainable from the boil-off gas using a compressor The need is reduced.

In the art, the geometric compression ratio is defined as the ratio of the combustion chamber volume (BDC) at which the piston is at bottom dead center (BDC) and the combustion chamber volume at which the piston is at top dead center (TDC).

In a piston reciprocating engine, the geometric compression ratio only considers compressing the contents of the cylinder into the clearance volume above the piston at top dead center (TDC) and assumes equivalent compression and expansion. Thus, the geometric compression ratio is defined as the ratio of the combustion chamber volume at which the piston is at bottom dead center (BDC) and the combustion chamber volume at which the piston is at top dead center (TDC).

The effective compression ratio also takes into account exhaust valve events and intake boosting.

The engine according to the first aspect combines the diesel cycle and the Otto cycle to form a completely new cycle not previously seen in a large two-stroke turbocharged single-flow scavenging internal combustion engine.

In a possible implementation form of the first aspect, the engine further comprises a piston controlled scavenging port disposed within the cylinder liner for introducing scavenging air into the combustion chamber.

In a possible implementation form of the first aspect, the engine further comprises an exhaust gas outlet disposed within the cylinder cover and controlled by the exhaust valve.

In a possible implementation form of the first aspect, the engine further comprises at least one fuel valve for delivering gaseous fuel to the combustion chamber.

In a possible implementation form of the first aspect, the engine further comprises a connection to a first pressurized gaseous fuel source, and the first pressurized gaseous fuel source preferably has a first pressure P1.

In a possible implementation form of the first aspect, the engine further comprises a connection to a second source of pressurized gaseous fuel, the second source of pressurized gaseous fuel, preferably having a second pressure P2 lower than the first pressure.

In a possible implementation form of the first aspect, the engine is configured to introduce a first amount of pressurized gaseous fuel and inject a second amount of high-pressure gaseous fuel within a single engine cycle.

In a possible implementation form of the first aspect, the engine is configured to inject a second amount of high pressure gaseous fuel in the first case when the piston reaches TDC after introducing a first amount of pressurized gaseous fuel.

In a possible implementation form of the first aspect, the engine is configured to introduce a third amount of ignition liquid after introducing the first amount of gaseous fuel and before or at the same time as injecting the second amount of gaseous fuel.

In a possible implementation form of the first aspect, the engine comprises one or more dedicated ignition fluid valves per cylinder.

In a possible implementation form of the first aspect, the engine comprises one or more gas injection valves disposed on the cylinder cover for injecting a second amount of gaseous fuel into the at least one combustion chamber, the gas injection valve being a first gaseous fuel source Is connected to

In a possible implementation form of the first aspect, the engine comprises one or more gas inlet valves disposed in the cylinder liner for introducing a first amount of gaseous fuel into the at least one combustion chamber, the gas inlet valve being a second gaseous fuel source. Is connected to

In a possible embodiment of the first aspect, the first pressure P1 is a high pressure, preferably a pressure above 150 bar.

In a possible embodiment of the first aspect, the second pressure P2 is a medium pressure, preferably between 10 and 30 bar.

In a possible implementation form of the first aspect, the first amount of gaseous fuel forms 20 to 80%, preferably 30 to 70% of the total amount of gaseous fuel delivered to the combustion chamber during a given engine cycle, and the second amount of gaseous fuel Forms 20 to 80%, preferably 30 to 70%, of the total amount of gaseous fuel delivered to the combustion chamber during a given engine cycle.

In a possible implementation form of the first aspect, the third amount of ignition liquid forms less than 5%, preferably less than 3%, of all fuel calorific values delivered to one or more combustion chambers during a given engine cycle.

In a possible implementation form of the first aspect, the engine comprises one or more controllers, the controller being connected to and controlling one or more fuel valves, and the controller is configured to operate the one or more fuel valves to:

Receiving a first amount of gaseous fuel from the second pressurized gaseous fuel source into the at least one combustion chamber during the stroke of the piston from BDC to TDC; And

When the piston is at or near the TDC, injecting a second amount of gaseous fuel from the first pressurized gaseous fuel source into the at least one combustion chamber.

In a possible implementation form of the first aspect, the engine comprises one or more controllers, the controller being connected to the control of the fuel inlet valve and the fuel injection valve, the controller being configured to:

Actuating a fuel inlet valve that introduces a first amount of gaseous fuel from the second pressurized gaseous fuel source into the at least one combustion chamber during the stroke of the piston from BDC to TDC; And

When the piston is at or near the TDC, actuating a fuel injection valve that injects a second amount of gaseous fuel from the first pressurized gaseous fuel source into the one or more combustion chambers.

In a possible implementation form of the first aspect, the engine further comprises a low pressure operating mode, wherein the engine introduces a first amount of gaseous fuel from the fuel source of the second pressurized gas into the at least one combustion chamber during the stroke of the piston from BDC to TDC. And not injecting a second amount of gaseous fuel from the source of the first pressurized gaseous fuel into the at least one combustion chamber when the piston is at or near the TDC.

In a possible implementation form of the first aspect, the engine further comprises a high pressure mode of operation, the engine injecting a second amount of gaseous fuel from the fuel source of the first pressurized gas into the at least one combustion chamber at or near the TDC, It is configured not to inject a first amount of gaseous fuel into the at least one combustion chamber from the source of the second pressurized gaseous fuel during the stroke of the piston from BDC to TDC.

In a possible implementation form of the first aspect, the engine comprises a plurality of combustion chambers each divided into a cylinder liner, a piston and a cylinder cover, the engine being configured to operate one or more combustion chambers with gaseous fuel as the main fuel in at least one operating mode. And the engine injects the amount of pressurized gaseous fuel into the combustion chamber remaining during the stroke of the piston 10 from BDC to TDC, and does not inject the amount of high-pressure gaseous fuel into the remaining combustion chamber when the piston is at or near the TDC. It is further configured with at least one operating mode. Thus, the remaining combustion chamber/cylinder can be operated in a conventional manner with the introduction of relatively low pressure gas during the upward movement of the piston. That is, one or more selected combustion chambers/cylinders are operated according to the first aspect.

According to a second aspect, there is provided a method of operating a large two-stroke turbocharged single-flow scavenging internal combustion engine having at least one combustion chamber divided into a cylinder liner, a piston and a cylinder cover, which is a gaseous fuel as the main fuel, the method comprising: Includes steps.

Reciprocating the piston between the top dead center (TDC) and the bottom dead center (BDC);

Introducing a first amount of pressurized gaseous fuel into one or more combustion chambers during a piston stroke from BDC to TDC; And

Injecting a second amount of high pressure gaseous fuel into one or more combustion chambers when the piston is at or near the TDC.

The method according to the second aspect provides the same advantages as the engine according to the first aspect.

According to a third aspect, there is provided a large two-stroke turbocharged single-flow scavenging internal combustion engine operated according to the method of the second aspect.

According to a fourth aspect, there is provided a large two-stroke turbocharged short-term scavenging internal combustion engine configured to operate gaseous fuel as the primary fuel in one or more operating modes, the engine comprising:

At least one combustion chamber divided into a cylinder liner, a piston and a cylinder cover;

A piston disposed to reciprocate between a top dead center (TDC) and a bottom dead center (BDC) in the cylinder liner;

A piston control scavenging port disposed on the cylinder liner to introduce scavenging air into the combustion chamber;

An exhaust gas outlet disposed on the cylinder cover and controlled by an exhaust valve;

At least one gas inlet valve, preferably disposed on the cylinder liner, for introducing a first amount of gaseous fuel into the at least one combustion chamber; And

One or more gas injection valves disposed in the cylinder cover for injecting a second amount of gaseous fuel into the one or more combustion chambers.

The engine according to the fourth aspect provides the same advantages as the engine according to the first aspect.

In a possible embodiment of the fourth aspect, the gas injection valve is connected to a first gaseous fuel source having a first pressure P1, which first pressure P1 is preferably between about 150 bar and about 450 bar.

In a possible implementation form of the fourth aspect, the gas inlet valve is connected to a second gaseous fuel source having a second pressure P2 lower than the first pressure P1, wherein the second pressure P1 is preferably approximately It is between 10 bar and approximately 30 bar.

In a possible implementation form of the fourth aspect, the engine includes:

A connection to a first pressurized gaseous fuel supply source having a first pressure P1; And

A connection to a second pressurized gaseous fuel source having a second pressure P2 lower than the first pressure P1.

In a possible implementation form of the fourth aspect, the engine is configured to perform the following in one or more modes of operation.

Receiving a first amount of gaseous fuel from a second pressurized gaseous fuel source into one or more combustion chambers during the stroke of the piston from BDC to TDC; And

Injecting a second amount of gaseous fuel into one or more combustion chambers from the first pressurized gaseous fuel source in the same engine cycle when the piston is at or near the TDC.

In a possible implementation form of the fourth aspect, the first amount of gaseous fuel forms 20 to 80%, preferably 30 to 70% of the total amount of gaseous fuel delivered to the combustion chamber during a given engine cycle, and the second amount of gaseous fuel Forms 20 to 80%, preferably 30 to 70%, of the total amount of gaseous fuel delivered to the combustion chamber during a given engine cycle, and a third amount of ignition liquid is preferably delivered to one or more combustion chambers during a given engine cycle. Less than 5%, preferably less than 3% of all fuel calorific values are formed.

In a possible implementation form of the fourth aspect, the engine comprises one or more controllers, which controllers are connected to and control the fuel inlet valve and the fuel injection valve, the controller being configured to:

Actuating a fuel inlet valve that introduces a first amount of gaseous fuel from the second pressurized gaseous fuel source into the at least one combustion chamber during the stroke of the piston from BDC to TDC; And

When the piston is at or near the TDC, actuating a fuel injection valve that injects a second amount of gaseous fuel from the first pressurized gaseous fuel source into the one or more combustion chambers.

These and other aspects of the invention will become apparent from the following examples.

As described above, according to the present invention, there is an advantage in that it is possible to overcome or at least reduce the aforementioned problems as well as providing an engine and gaseous fuel supply system.

In the following detailed part of the disclosure, aspects, embodiments, and implementation forms of the present invention, it will be described in more detail with reference to exemplary embodiments shown in the drawings.
Fig. 1 is a front view of a large two-stroke engine according to an exemplary embodiment.
Figure 2 is a side view of the large two-stroke engine of Figure 1;
3 is a first schematic diagram of a large two-stroke engine according to FIG. 1;
4 is a cross-sectional view of the cylinder frame and cylinder liner of the FIG. 1 engine including a cylinder cover and an exhaust valve mounted on the cylinder cover and the pistons shown in both TDC and BDC.
5 is a graph showing a gas exchange and fuel injection cycle.
6 is a schematic diagram of a gaseous fuel supply system according to an embodiment.
7 is a schematic diagram of a gaseous fuel supply system according to another embodiment.
8 is a cross-sectional view of a cylinder frame and a cylinder liner according to another embodiment.

In the detailed description below, an internal combustion engine will be described with reference to a large two-stroke low-speed turbocharged internal combustion crosshead engine of an exemplary embodiment. 1, 2 and 3 show an embodiment of a large low-speed turbocharged two-stroke internal combustion engine with a crankshaft 8 and a crosshead 9. Figs. 1 and 2 are a front view and a side view, respectively. 3 is a schematic diagram of a large low speed turbocharged two-stroke diesel engine equipped with an intake and exhaust system. In this exemplary embodiment, the engine has four cylinders built in rows. Large low-speed turbocharged two-stroke internal combustion engines typically have four to fourteen cylinders in rows, supported by the engine frame 11. This engine can be used, for example, as a main engine of a ship or a stationary engine that operates a generator of a power plant. The total power of this engine may for example range from 1,000 to 110,000 kW. The engine combines gaseous fuel as the main fuel for the diesel and Otto cycles in operating mode. This is because, although compression ignition is performed, a mixture of air and fuel forming the first amount of pressurized gaseous fuel introduced during the compression stroke of the piston 10 is also compressed. The compressed air and fuel mixture is ignited when a second amount of high pressure gas house fuel is injected at or near the TDC.

Another mode of operation of the engine may operate according to a diesel cycle in which no fuel is introduced during the compression stroke and all fuel is injected at or near the TDC, which may also have gaseous fuel as the main fuel. In another mode of operation, the engine can be operated according to an auto cycle in which all gaseous fuel is mixed with scavenging, the mixture of air and fuel is compressed during the compression stroke and temporal ignition is provided at or near the TDC.

The engine, in this exemplary embodiment, is a two-stroke single-flow scavenging type engine with a scavenging port 18 in the lower region of the cylinder liner 1 and a central exhaust valve 4 at the top of the cylinder liner 1. Accordingly, the combustion chamber is divided into a cylinder liner 1, a piston 10 arranged to reciprocate in the cylinder liner between the bottom dead center (BDC) and the top dead center (TDC), and the cylinder cover 22. The geometric compression ratio of the engine exceeds 20.

When the scavenging piston is below the scavenging port 18, it passes from the scavenging receiving portion 2 through the scavenging port 18 at the bottom of the individual cylinder 1. When the piston is moving upward and before passing through the fuel valve 30, gaseous fuel is introduced from the gaseous fuel inlet valve 30 under the control of the electronic controller 60. The fuel valve 30 is preferably evenly distributed around the circumference of the cylinder liner and is disposed somewhere in the central region of the length of the cylinder liner 1. Thus, the inflow of gaseous fuel occurs when the compression pressure is relatively low, that is, when the piston reaches TDC and is much lower than the compression pressure. The engine is configured to introduce a certain amount of gaseous fuel during the compression stroke so that the mixture of air and fuel in the combustion chamber has an air-fuel ratio (air mass/fuel mass (eg LNG (methane) or LPG) of greater than 50). If the air-fuel ratio of the combustion chamber exceeds 50 during the compression stroke, the risk of early ignition is greatly reduced.

The piston 10 of the cylinder liner 1 compresses the fill gas fuel and scavenging air, and the high pressure gaseous fuel is injected through the fuel injection valve 50 at or near the TDC. The injection of the high-pressure fuel at or near the TDC causes ignition according to the diesel principle due to the high pressure in the combustion chamber or the high temperature near the TDC, and the significantly reduced air-fuel ratio in the combustion chamber caused by the additional amount of fuel in the high-pressure injection is probably fuel injection. A third small amount of pilot oil (or any other suitable ignition fluid) injected with gaseous fuel by valve 50 or delivered by a dedicated pilot oil fuel valve 51 preferably arranged in the cylinder cover 22 You can get support by

"At or near TDC" means a range that includes injection of gaseous fuel starting at about 15 degrees before TDC and ending at about 40 degrees after TDC, even if the piston is fast.

Subsequently, combustion proceeds and exhaust gas is produced. An alternative form of ignition system, such as a prechamber (not shown), laser ignition (not shown) or a glow plug (not shown), in place of or in addition to the pilot oil fuel valve 50. Can also be used to start ignition.

When the exhaust valve 4 is opened, the exhaust gas flows to the exhaust gas receiving portion 3 through the exhaust duct coupled with the cylinder 1, and continues to the turbine of the turbocharger 5 through the first exhaust conduit 19. After flowing to (6), this exhaust gas is discharged to the outlet 21 and the atmosphere via the economizer 20 through the second exhaust conduit. The turbine 6 drives a compressor 7 through which fresh air is supplied via an air inlet 12 through a shaft. The compressor 7 delivers the pressurized scavenging air to the scavenging conduit 13 leading to the scavenging receiving portion 2. The scavenging air in this conduit 13 passes through the intercooler 14 for desired cooling.

If the compressor 7 of the turbocharger 5 does not deliver sufficient pressure to the scavenging receiving portion 2, i.e. in a low or partial load condition of the engine, the cooled scavenging air pressurizes the electric motor 17 Passes through the auxiliary blower 16 driven by ). At higher engine loads, the turbocharger compressor 7 delivers a sufficiently pressurized scavenging air, and then the auxiliary blower 16 is bypassed via a non-return valve 15.

3 shows a controller 60, such as an electronic control device, connected to the engine parts controlled by the sensor and the controller 60 that provide information about the operating conditions of the engine to the controller through a signal line or other communication channel. Shows. One of the sensors is shown in the form of a crank angle sensor, which informs the controller 60 of the angle of rotation of the crankshaft 8. The controller 60 controls the operation of the fuel inlet valve 30, the fuel injection valve 50 and the exhaust valve 4.

The controller 60 is connected to the fuel inlet valve 30 and the fuel injection valve 50 to control, and the controller 60 is at least one from the second pressurized gas fuel supply source 40 during a piston stroke from BDC to TDC. The fuel inlet valve is operated so that a first amount of gaseous fuel is introduced into the combustion chamber, and a second into at least one combustion chamber from the pressurized first high pressure gaseous fuel supply 35 when the piston 10 is at or near the TDC. It is configured to operate the fuel injection valve 50 to inject positive gaseous fuel.

4 shows a cylinder liner 1 generally designated for a large two-stroke crosshead engine. Depending on the engine size, the cylinder liner 1 can be manufactured in different sizes, typically with cylinder bores in the range of 250 mm to 1000 mm and corresponding typical lengths in the range of 1000 mm to 4500 mm.

In Fig. 4, the cylinder liner 1 is shown mounted on a cylinder frame 23 with a cylinder cover 22 disposed on top of the cylinder liner 1 with an airtight interface therebetween. See drawing

In Fig. 4, the piston 10 is schematically shown with a dotted line at both the bottom dead center (BDC) and the top dead center (TDC), but of course these two positions do not occur at the same time and are separated by 180 degree rotation of the crankshaft 8 It is clear. The cylinder liner (1) is provided with a cylinder lubrication hole (25) and a cylinder lubrication line (24) to provide a supply of cylinder lubrication oil when the piston (10) passes through the lubrication line (24), followed by a piston ring (not shown). Si) distributes the cylinder lubricating oil to the working surface of the cylinder liner.

A fuel injection valve 50 (generally, two or three fuel injection valves 50 are distributed circumferentially around the exhaust valve 4 for each cylinder) is mounted on the cylinder cover 22 and the first supply conduit ( It is connected to the first high pressure gaseous fuel supply 35 via 36) and to the supply of pilot oil 27 via pilot line 28.

The amount of the third ignition liquid forms less than 5%, preferably less than 3%, of the total amount of fuel calorific value delivered to the combustion chamber during a given engine cycle.

The fuel injection valve 50 may be of the type disclosed in DK178519B1, which can inject a significant amount of high pressure gaseous fuel into the combustion chamber with a small amount of pilot oil.

The timing of injection of high pressure gaseous fuel and pilot oil by the fuel injection valve 50 is controlled by the electronic control device 60, and the electronic control device 60 injects fuel through a signal line schematically indicated by a dotted line in FIG. It is connected to the valve 50.

The fuel inlet valve 30 is installed in a cylinder liner whose nozzle/inlet opening is substantially the same height as the rear end of the fuel valve 30 protruding from the inner surface of the cylinder liner 1 and the outer wall of the cylinder liner 1. Typically, each cylinder liner 1 distributed circumferentially around the cylinder liner 1 is provided with one or two, or perhaps up to three or four, fuel inlet valves 30. The fuel inlet valve 30 is arranged substantially midway along the length of the cylinder liner 1 in one embodiment.

The inflow of medium pressure gaseous fuel by the fuel inlet valve 30 is controlled by the electronic control device 60, and the electronic control device 60 is in an embodiment through a signal line schematically shown in FIG. It is connected to the fuel inlet valve 30.

The engine is configured to introduce a first amount of pressurized gaseous fuel and to inject a second amount of high pressure gaseous fuel within a single engine cycle. That is, the second amount of high-pressure gaseous fuel is injected in the first case when the piston reaches the TDC after the first amount of the pressurized gaseous fuel is introduced.

In addition, FIG. 4 shows a first high-pressure gaseous fuel supply source 35 and a fuel supply pipe connected to each of the fuel injection valves 50 in the cylinder cover 22 through the first supply conduit 36, respectively. The gas supply system of an engine having a second medium pressure gaseous fuel supply 40 connected to the inlet of the gaseous fuel valve 30 of is shown in a schematic and simplified manner.

In one embodiment, the high pressure P1 of the first high pressure gaseous fuel source 35 may be approximately 15 to 45 MPa (150 to 450 bar), so that the gaseous fuel overcomes the peak compression pressure and is injected at or near the TDC. Make it possible.

In one embodiment, the medium pressure P2 of the second medium pressure gaseous fuel supply source 40 may be approximately 1 to 3 MPa (10 to 30 bar), so that the gaseous fuel can be introduced during the compression stroke.

5 shows the opening and closing periods of the scavenging port 18, the exhaust valve 4, the fuel inlet valve 30 (GA fuel valve), and the fuel injection valve 50 (GI fuel valve) as a crank angle (the angle of the crankshaft ( It is a graph shown as a function of 8)). The graph shows that the window for introducing the gaseous fuel is relatively short and allows a very short time for the gaseous fuel to mix with the scavenging air in the combustion chamber. This very short window allows gaseous fuel. High pressure gaseous fuel is injected into the window around the TDC.

The total amount of gaseous fuel delivered (in and injected) per engine cycle is determined by the engine load. The total amount of gaseous fuel delivered is the sum of the first amount of gaseous fuel flowing into the cylinder at the pressure P2 and the second amount of high-pressure gaseous fuel injected into the cylinder at the pressure P1. In one embodiment, up to approximately 70 or 80% of the gaseous fuel calorific value delivered to the cylinder is gaseous fuel introduced from the second source 40 of gaseous fuel pressurized at pressure P2. In one embodiment, up to approximately 70 or 80% of the gaseous fuel calorific value delivered to the cylinder is gaseous fuel injected from the second high-pressure gaseous fuel source 35 at pressure P2.

Accordingly, the ratio between the first gaseous fuel amount and the second gaseous fuel amount can be adjusted to match the amount of available fuel of each gaseous fuel supply source. That is, if relatively little high-pressure fuel is available in the first source, the engine is at or near a relatively large amount of medium-pressure gaseous fuel and TDC entering the cylinder from the second source 40 of pressurized gaseous fuel during the compression stroke. It can operate with relatively small amounts of injected high-pressure gaseous fuel. On the other hand, when relatively little intermediate pressurized gaseous fuel is available from the second pressurized gaseous fuel source 40, the engine will have a relatively large amount of high-pressure gaseous fuel from the first high-pressure gaseous fuel source injected into the cylinder at or near the TDC. And a relatively small amount of fuel from the second pressurized gaseous fuel source introduced into the cylinder during the compression stroke.

6 is a schematic diagram of a gas supply system that can be used to supply gaseous fuel to a large two-stroke turbocharged internal combustion engine such as the engine shown in FIGS. 1 to 4. 1 to 4. The gas supply system is, in one embodiment, installed on a liquefied gas tanker, that is, a marine vessel carrying a large amount of liquefied gaseous fuel such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG) mainly composed of methane.

The gas supply system uses pressurized gaseous fuel as the main engine of marine vessels and other consumers of marine vessel gas fuel, such as a generator set for producing heat and power for marine vessels (generator sets are generally considerably smaller than the main engine and have a generator/alternator). It is a driven four-stroke internal combustion engine), in particular when the main engine is stopped (eg when a marine vessel is in port for freight) or is configured to supply a boiler running on gaseous fuel.

The gas supply system is also configured to supply high pressure gaseous fuel to the main engine for injecting gaseous fuel at or near the TDC.

Thus, the gas supply system includes a second pressurized gaseous fuel source, denoted by 40 (indicated by a dotted rectangle in Fig. 6) to provide gaseous fuel at a pressure P2 (eg 10 to 30 bar). Thus, the gas supply system includes a first high pressure gaseous fuel source, denoted by 35 (indicated by a dotted rectangle in FIG. 6) to provide gaseous fuel at a pressure P1 (eg 150 to 30 bar).

The gaseous fuel supply system includes one or more (insulating) storage tanks 26 and a high pressure cryogenic pump unit 37 for storing liquefied gaseous fuel in cryogenic conditions. The inlet of the high pressure cryogenic pump unit is connected to the storage tank for supplying liquefied gaseous fuel to the high pressure pump 37. The stream of cryogenic liquefied gaseous fuel to the high pressure cryogenic pump generally has a pressure between bar and 10 bar slightly above zero, such as a pressure of about 5 bar and a temperature of, for example, about 110 K.

The first supply conduit 36 is connected to the outlet of the high pressure cryogenic pump unit 37 to convey the high pressure liquefied gaseous fuel stream from the high pressure pump 37 through the high pressure carburetor 38, in the high pressure carburetor 38, The stream of high pressure (vaporized) gaseous fuel passes through the heater 39 and is then conveyed to the high pressure fuel injection system of the main engine. The step of heating the stream of high-pressure gaseous fuel in the heater 39 is optional, and it may be necessary to ensure that the gaseous fuel delivered to the injection system of the main engine is warm enough to be processed by the injection system (this is generally Since the injection system is not suitable for handling cryogenic temperatures, it is often necessary to increase the temperature of the stream high pressure gaseous fuel depending on the material used and the configuration of the injection system).

The stream of high pressure gaseous fuel leaving the high pressure cryogenic pump unit 37 generally has a temperature of between 150 and 450 bar, such as 350 bar and such as about 119 K.

The stream of high pressure (gasification) gaseous fuel leaving the high pressure carburetor 38 generally has a temperature of between 150 and 450 bar, such as 350 bar and such as about 154 K. After passing through the heater 39, the temperature of the high-pressure gaseous fuel stream has a pressure that is substantially unchanged and a temperature of, for example, about 318 K.

Thus, the stream of high pressure liquefied gaseous fuel in the embodiment has a pressure in excess of 150 bar and passes through the high pressure carburetor 38 to convert the high pressure liquefied gaseous fuel stream into a stream of high pressure gaseous fuel for injection in the main engine.

The boil-off gas conduit 42 connects the boil-off gas outlet of the storage tank to the inlet of the compressor unit 48 to convey the boil-off gas stream to the compressor unit. A first heat exchanger 43 is arranged in the boil-off gas conduit 42 to increase the temperature of the boil-off gas stream to the compressor unit 48. In one embodiment, the pressure of the boil-off gas in the boil-off gas conduit 42 is about 1 bar, and has a temperature of about 140 K, for example. After passing through the heat exchanger 43, the temperature rises to, for example, about 230K.

The compressor unit 48 increases the pressure of the boil-off gas stream to produce a stream of pressurized gaseous fuel at the outlet, for example, to a pressure of about 15 bar and a temperature of about 318 K. Compressor unit 48 In one embodiment, it may be a compressor or a multistage compressor unit (as shown) and includes a cooler 45 after each stage.

The second supply conduit 41 is, for example, one or more consumers of pressurized gaseous fuel (e.g., a main engine for the introduction of pressurized gaseous fuel during the compression stroke, or a generator set or boiler via the engine generator supply conduit 47). It is connected to the outlet of the compressor unit 48 for conveying a first portion of the gaseous fuel stream pressurized to.

The reliquefaction conduit 46 is also connected to the outlet of the compressor unit 48 and a second portion of the gaseous fuel stream pressurized through the heat exchanger 43 to exchange heat with the vaporized gas flowing through the heat exchanger 43 And then passing the stream of pressurized gaseous fuel through the high-pressure carburetor 38 to exchange heat with the stream of high-pressure liquefied or vaporized gaseous fuel flowing through the high-pressure carburetor 38. After the stream of pressurized gaseous fuel has passed through the heat exchanger 43, for example, the temperature is 159 K and the pressure that does not change substantially is about 15 bar. After pressurizing the stream of pressurized gaseous fuel through the high-pressure vaporizer 38, it is cooled by the stream of vaporized high-pressure gaseous fuel, e.g., the temperature is 122 K and has a pressure of about 15 bar substantially unchanged, and reliquefaction Most of the stream of pressurized gaseous fuel in conduit 46 is reliquefied.

Downstream of the high pressure carburetor 38 a reliquefaction conduit 46 is connected to the separation vessel 32 to collect the liquefied gaseous fuel produced by the cooling effect of the high pressure carburetor 38. Separation vessel 32 separates still gaseous fuel in the form of reliquefied gaseous fuel. A reliquefied gas conduit 33 connects the liquid outlet of the separation vessel 32 to the inlet of the storage tank 26 for conveying the reliquefied gaseous fuel to the storage tank 26. The gas recirculation conduit 34 connects the gas outlet of the separation vessel 32 to the boil-off gas conduit 42 so that the residual gaseous fuel can participate in other liquefaction cycles.

FIG. 7 shows another embodiment of a gaseous fuel supply system essentially identical to the gas supply system according to the embodiment of FIG. 6. In the embodiment of FIG. 7, structures and features that are the same as or similar to corresponding structures and features previously described or illustrated herein are denoted by the same reference numerals as previously used for simplification.

In this embodiment, in the regasification conduit 46 a throttling device 29, such as an expansion valve 29, is added between the vaporizer 38 and the separation vessel 32 to throttle a second portion of the pressurized gas stream. Submit to the ring process.

The throttling device 29 is an expansion valve 29 in one embodiment. The throttling device 29 provides an additional cooling effect, a Joule-Thomson effect (also referred to as Joule-Kelvin effect, Kelvin-Joule effect). The Joule-Thomson effect forces the temperature change of the actual gas or liquid (in distinction from the ideal gas) to be insulated through a valve or porous plug so that no heat is exchanged with the environment. This procedure is called the throttling process or the Joule-Thomson process. Gaseous fuels such as natural gas or petroleum gas are cooled by expansion by the Joule-Thomson process when throttling through an orifice. The gas cooling throttling process is generally used in cooling processes such as air conditioners, heat pumps and liquefiers.

In gaseous fuel supply systems, the liquefaction of boil-off gases is similar to the Hampson-Linde cycle commonly used for liquefaction of gases. The Hampson-Linde cycle depends on the Joule-Thomson effect and performs the following steps.

1) heating the gaseous fuel pressurized in the compressor unit 46 by compression to add external energy to provide what is needed to pass the cycle,

2) cooling by returning the gas from the next step (and the last step) in the heat exchanger 43,

3) immersing the gas in a cooler environment and losing some of its heat (and energy) in the high pressure carburetor 38,

4) Passing the gas through the Joule-Thomson orifice to remove heat but is further cooled by conserving energy, which is potential energy rather than kinetic energy.

Currently, most of the gaseous fuel is reliquefied, and the remaining gaseous fuel, which is most cooled in the current cycle, is recirculated and sent back to the compressor unit 46, heated when participating as a coolant in the heat exchanger 43, and sent back to the next step. The cycle is started and reheated by compression in the compressor unit 46.

The gas supply system consists of a compressor that provides a pressure of about 10 to 20 bar to handle all the boil-off gas produced by the storage tank, and a high pressure vaporization system that provides 30 to 50% of the total amount of fuel required by the engine at maximum engine load. It can be relatively simplified.

The gas supply system has its own redundancy, which reduces costs by avoiding separate redundant systems.

8 shows another embodiment of a large two-stroke turbocharged internal combustion engine essentially identical to the gas supply system according to the embodiment of FIGS. 1 to 4. In the embodiment of Fig. 8, structures and features that are the same as or similar to the corresponding structures and features previously described or illustrated herein are denoted by the same reference numerals as previously used for simplification. The main difference of this embodiment to the embodiment of FIGS. 1 to 4 is that a gaseous fuel inlet valve 30 is disposed in the cylinder cover 22. This embodiment allows all fuel valves 30 and 50 to be located within the cylinder cover 22.

In one embodiment, the engine has a plurality of combustion chambers/cylinders, and one or a selected number of combustion chambers/cylinders of the engine is operated according to the above-described operating mode, wherein a relatively low pressure gas is injected during the upward stroke of the piston and , Gas with higher pressure is injected at or near the TDC. In this embodiment, the remaining combustion chamber/cylinder is operated by introducing gas only at a relatively low pressure during the upward stroke of the piston. That is, no high-pressure gas is injected at or near the TDC for these remaining cylinders. Alternatively, the remaining cylinders are operated with liquid fuel by injecting liquid fuel at or near the TDC.

The engine can have a mode of operation primarily intended to operate on a liquid fuel such as diesel oil injected at or near the TDC (eg marine diesel oil or heavy oil), making the engine a dual fuel engine.

Various aspects and embodiments have been described in connection with various embodiments herein. However, other modifications to the disclosed embodiments may be understood and performed by those skilled in the art when practicing the claimed subject matter by study of the drawings, disclosure and appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “one” or “a” does not exclude a plurality of. A single processor, controller, or other unit may be recited in the claims. The fact that a particular measure is simply recited in different dependent claims does not indicate that these combinations cannot be used to advantage. Reference signs used in the claims are intended to limit the scope. Should not be interpreted.

1: cylinder liner
4: exhaust valve
10: piston
18: small port
22: cylinder cover
35: first high pressure gaseous fuel source
40: second pressurized gas fuel source

Claims (15)

In a large two-stroke turbocharged single-flow scavenging internal combustion engine having at least one combustion chamber divided into a cylinder liner (1), a piston (10) and a cylinder cover (22),
The piston 10 is arranged to reciprocate between BDC and TDC with a geometric compression ratio of more than 20,
The internal combustion engine is configured to operate gaseous fuel as the main fuel in one or more operating modes,
The internal combustion engine,
A mode in which a first amount of pressurized gaseous fuel is introduced into at least one combustion chamber during the stroke of the piston (10) from BDC to TDC to obtain a mixture of air and fuel having an air-fuel ratio of more than 50 by mixing the scavenging air introduced into the combustion chamber; And
A mode of injecting a second amount of high pressure gaseous fuel into the at least one combustion chamber when the piston 10 is at or near the TDC; medium
A large two-stroke turbocharged single-flow scavenging internal combustion engine having at least one combustion chamber divided into a cylinder liner (1), a piston (10) and a cylinder cover (22) further configured in one or more modes. The method of claim 1,
A piston control scavenging port 18 disposed on the cylinder liner 1 for introducing scavenging air into the combustion chamber and/or
The exhaust gas outlet disposed on the cylinder cover 22 and controlled by the exhaust valve 4 and/or
One or more fuel valves for delivering gaseous fuel to the combustion chamber and/or
The first high pressure gaseous fuel supply source 35 connection to the; further includes,
The first high pressure gaseous fuel supply source 35 has a connection to the first pressure P1 and/or the second pressurized gaseous fuel supply source 40,
The second pressurized gas fuel supply source 40 has a second pressure (P2) lower than the first pressure (P1), at least one divided into a cylinder liner (1), a piston (10) and a cylinder cover (22). Large two-stroke turbocharged single-flow scavenging internal combustion engine with combustion chamber. The method of claim 2,
The internal combustion engine is configured to introduce the first amount of pressurized gaseous fuel and inject the second amount of high-pressure gaseous fuel within a single engine cycle, the cylinder liner (1), the piston (10) and the cylinder cover (22) Large two-stroke turbocharged single-flow scavenging internal combustion engine with one or more combustion chambers divided into. The method according to claim 1 or 2,
The internal combustion engine is configured to introduce a third amount of ignition liquid after injecting the first amount of pressurized gaseous fuel and before or at the same time as injecting the second amount of high-pressure gaseous fuel, the cylinder liner 1, the piston Large two-stroke turbocharged single-flow scavenging internal combustion engine having at least one combustion chamber divided into (10) and a cylinder cover (22). The method according to any one of claims 1 to 4,
The internal combustion engine is a large two-stroke turbocharged single-flow scavenging internal combustion engine having at least one combustion chamber divided into a cylinder liner (1), a piston (10) and a cylinder cover (22) including at least one dedicated ignition liquid valve per cylinder. . The method according to any one of claims 2 to 5,
The internal combustion engine includes one or more fuel injection valves 50 disposed on the cylinder cover 22 to inject the second amount of high-pressure gaseous fuel into the one or more combustion chambers,
The fuel injection valve 50 is a large two-stroke turbocharged single-flow scavenging device having at least one combustion chamber divided into a cylinder liner 1, a piston 10, and a cylinder cover 22 connected to the first high-pressure gaseous fuel supply source. Type internal combustion engine. The method according to any one of claims 2 to 6,
The internal combustion engine comprises at least one fuel inlet valve 30, preferably disposed on the cylinder liner 1, for introducing the first amount of pressurized gaseous fuel into the at least one combustion chamber,
The fuel inlet valve 30 is a large two-stroke turbocharged single flow scavenging device having at least one combustion chamber divided into a cylinder liner 1, a piston 10, and a cylinder cover 22 connected to the first pressurized gas fuel supply source. Type internal combustion engine. The method according to any one of claims 2 to 7,
The first pressure (P1) is a high pressure, preferably more than 150 bar, a large two-stroke turbocharged single-flow scavenging type having at least one combustion chamber divided into a cylinder liner (1), a piston (10) and a cylinder cover (22). Internal combustion engine. The method according to any one of claims 2 to 8,
The second pressure (P2) is a medium pressure, preferably a pressure between 10 and 30 bar, a large two-stroke turbocharging having one or more combustion chambers divided into a cylinder liner (1), a piston (10) and a cylinder cover (22) Single-flow scavenging internal combustion engine. The method according to any one of claims 1 to 9,
The first amount of pressurized gaseous fuel forms 20 to 80%, preferably 30 to 70%, of the total amount of gaseous fuel delivered to the combustion chamber during a given engine cycle,
The second amount of high pressure gaseous fuel forms 20 to 80%, preferably 30 to 70% of the total amount of gaseous fuel delivered to the combustion chamber during a given engine cycle, cylinder liner 1, piston 10 and cylinder A large two-stroke turbocharged single-flow scavenging internal combustion engine having one or more combustion chambers separated by a cover 22. The method according to any one of claims 4 to 10,
The third amount of ignition fluid forms less than 5%, preferably less than 3%, of the total amount of fuel calorific value delivered to the one or more combustion chambers during a given engine cycle, the cylinder liner 1, the piston 10 and the cylinder cover. (22) A large two-stroke turbocharged single-flow scavenging internal combustion engine with one or more combustion chambers. The method according to any one of claims 2 to 11,
Including one or more controllers 60,
The controller 60 is connected to and controlled with the one or more fuel inlet valves 30 and 50,
The controller 60,
Introducing a first amount of gaseous fuel from the second pressurized gaseous fuel supply source 40 to the at least one combustion chamber during the stroke of the piston 10 from BDC to TDC;
When the piston 10 is at or near the TDC, to inject a second amount of gaseous fuel from the source 35 of the first high pressure gaseous fuel into the at least one combustion chamber,
A large two-stroke turbocharged single-flow scavenging internal combustion engine having at least one combustion chamber divided into a cylinder liner (1), a piston (10) and a cylinder cover (22), configured to operate the at least one fuel valve. The method according to any one of claims 6 or 7,
Including one or more controllers 60,
The controller 60 is connected to the fuel inlet valve 30 and the fuel injection valve 50 to control,
The controller 60,
Operating the fuel inlet valve 30 for introducing a first amount of gaseous fuel from the second pressurized gaseous fuel supply source 40 to the at least one combustion chamber during the stroke of the piston 10 from BDC to TDC;
When the piston 10 is at or near the TDC, configured to operate the fuel injection valve for injecting a second amount of gaseous fuel from the first high pressure gaseous fuel supply 35 into the one or more combustion chambers, A large two-stroke turbocharged single-flow scavenging internal combustion engine having at least one combustion chamber divided into a cylinder liner (1), a piston (10) and a cylinder cover (22). The method according to any one of claims 2 to 13,
It further includes a low pressure operating mode,
The internal combustion engine introduces the first amount of pressurized gaseous fuel from the fuel supply source of the second pressurized gas into the at least one combustion chamber during the stroke of the piston 10 from BDC to TDC,
Cylinder liner (1) configured not to inject the second amount of gaseous fuel from the first high-pressure gaseous fuel source 35 into the one or more combustion chambers when the piston (10) is at or near the TDC. , A large two-stroke turbocharged single-flow scavenging internal combustion engine having one or more combustion chambers divided into a piston 10 and a cylinder cover 22. The method according to any one of claims 2 to 14,
It further includes a high pressure operating mode,
The internal combustion engine injects the second amount of high pressure gaseous fuel from the first high pressure gaseous fuel source 35 into the at least one combustion chamber when the piston is at or near the TDC,
Cylinder liner (1), configured not to introduce the first amount of pressurized gaseous fuel from the fuel supply source 40 of the second pressurized gas into the at least one combustion chamber during the stroke of the piston 10 from BDC to TDC, A large two-stroke turbocharged single-flow scavenging internal combustion engine having one or more combustion chambers divided into a piston 10 and a cylinder cover 22.

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