KR20230150760A - A large turbocharged two-stroke uniflow crosshead compression ignition internal combustion engine and method for operating such engine - Google Patents

Abstract

A large turbocharged two-stroke Uniflow crosshead compression ignition internal combustion engine is disclosed, the engine having at least one operating mode operating with both ammonia and an ignition fluid such as fuel oil as fuel for combustion within the engine; , the engine is:
- at least one cylinder with an internally reciprocating piston (10) and a cylinder liner (1) and a cylinder cover (22) covering the cylinder,
- A combustion chamber formed inside the cylinder between the reciprocating piston (10) and the cylinder cover (22),
- an ammonia fuel system (30) configured to supply pressurized ammonia to at least one ammonia fuel valve (50) arranged in the cylinder cover (22) or the cylinder liner (1), and
- an ignition fluid system (40) configured to supply pressurized ignition fluid to at least one ignition fluid valve (50) arranged in the cylinder cover (22) or cylinder liner (1). This engine is unique in that the ignition fluid system 40 is configured to supply ignition fluid to the combustion chamber with an injection duration of at least 20% of the determined duration of ammonia fuel combustion.
Accordingly, a more complete combustion of ammonia is ensured by injecting the ignition fluid into the combustion chamber of the cylinder of the internal combustion engine over a longer period of time in connection with the known practice. Additionally, since a full rate fuel oil injection system can be used, the pilot fuel oil injection system can be omitted, thus saving a considerable amount of space and considerable cost for installing the fuel injection valve in the cylinder cover. Provides savings. Moreover, during dual fuel operation using both ammonia and an ignition fluid such as fuel oil, the fuel oil injection system also continues to run and thus remains clean and ready to switch from ammonia dual fuel operation to fuel oil operation.

Description

Large turbocharged two-stroke Uniflow crosshead compression ignition internal combustion engine and operating method of the engine {A LARGE TURBOCHARGED TWO-STROKE UNIFLOW CROSSHEAD COMPRESSION IGNITION INTERNAL COMBUSTION ENGINE AND METHOD FOR OPERATING SUCH ENGINE}

The present invention relates to a large turbocharged two-stroke Uniflow crosshead compression ignition internal combustion engine, which operates with both an ignition fluid such as fuel oil and ammonia as fuel for combustion within the engine. silver:

- at least one cylinder with an internally reciprocating piston and a cylinder liner and a cylinder cover covering said cylinder,

- A combustion chamber formed inside the cylinder between the reciprocating piston and the cylinder cover,

- an ammonia fuel system configured to supply pressurized ammonia to at least one ammonia fuel valve arranged in the cylinder cover or cylinder liner, and

- an ignition fluid system configured to supply pressurized ignition fluid to at least one ignition fluid valve arranged in the cylinder cover or cylinder liner.

Includes.

Large turbocharged two-stroke Uniflo crosshead compression ignition internal combustion engines are typically used as prime movers in large oceangoing vessels such as container ships or in power plants. Often, these engines run on heavy oil or fuel oil. The sheer size, weight and power output make them so different from conventional combustion engines that they place large two-stroke turbocharged compression-ignition internal combustion engines in a category unto themselves.

In the past, internal combustion engines were mainly operated with hydrocarbon fuels such as fuel oil, such as diesel oil, or fuel gas, such as natural gas or petroleum gas. Combustion of hydrocarbon fuels releases carbon dioxide (CO ₂ ) as well as other greenhouse gases that contribute to air pollution and climate change. Unlike fossil fuel impurities that result in by-product emissions, _CO2 is an unavoidable result of hydrocarbon combustion. A fuel's _CO2 footprint and energy density depend on the hydrocarbon chain length and complexity of the hydrocarbon molecule. Therefore, gaseous hydrocarbon fuels have a smaller footprint than liquid hydrocarbon fuels, but gaseous hydrocarbon fuels have the disadvantage of being more difficult and expensive to handle and store. To reduce the CO ₂ footprint, non-hydrocarbon fuels are being explored.

Ammonia is a product obtained from fossil fuels, biomass, or renewable sources (wind, solar, hydro, or heat), and when produced by renewable sources, ammonia has virtually no carbon footprint, or when burned, produces only CO ₂ , _SO Does not emit , particulate matter, or unburned hydrocarbons. Currently, ammonia can be produced in an environmentally friendly way using electricity from renewable energy sources such as solar, wind and wave energy, and because the combustion of ammonia itself occurs without forming carbon-containing greenhouse gases such as carbon dioxide. , it is receiving great attention as a fuel for internal combustion engines.

WO 2020/252518 A1 describes a large turbocharged two-stroke Uniflow crosshead compression ignition internal combustion engine of the type mentioned in the introduction.

When using ammonia as a fuel in an internal combustion engine, the engine can be operated according to Otto's principle, which introduces the ammonia fuel at a relatively low pressure during the compression stroke of the piston, or the ammonia fuel can be introduced when the piston approaches top dead center (TDC). The engine can also be operated according to the principle of diesel being injected at high pressure into the combustion chamber. During the ammonia fuel injection and combustion stages of the piston cycle, the cylinder pressure experiences rapid level changes due to compression/expansion of the chamber and due to combustion occurring.

Ammonia has been tested and used on a small scale in small spark-ignition internal combustion engines, but has not yet been used on a large scale to power compression-ignition internal combustion engines.

There are several problems with using ammonia as fuel. One problem is that the power density is lower than that of typical hydrocarbon fuels, so much more fuel must be injected, resulting in larger flows. Such larger flows can cause flame extinction, i.e., even if ignition occurs at the very beginning of an injection event, the subsequent large flow and resulting high velocity of the fuel jet blows out the flame. I order it. Another problem is ammonia's low willingness to ignite (low flammability) compared to liquid hydrocarbon fuels. Another problem is the high evaporative cooling of ammonia, which cools the fuel during injection, increasing the required ignition energy. High temperature in the combustion chamber due to high evaporative cooling is a prerequisite for stable combustion. The combination of these problems has so far hindered the use of ammonia as the primary fuel in compression ignition engines.

Internal combustion engines that can run on two different fuels are generally called dual-fuel engines. The two different fuels in a dual fuel engine are generally a fuel oil such as heavy oil or diesel capable of compression ignition, and a gaseous fuel to which an ignition fluid, for example in the form of pilot fuel oil, needs to be added, such as ammonia, methanol, LPG, LNG, It is composed of another fuel such as ethane. Therefore, the existing technical solution concept for a dual-fuel engine running on ammonia and fuel oil is that the engine runs at maximum rating with oil fuel only, or with ammonia fuel at maximum rating with a minimum of pilot fuel oil for ignition of the ammonia fuel. . The existing concept consists of a fuel oil injection system optimized for the delivery of a full-rate portion of fuel oil, an ammonia fuel system optimized for full-rate ammonia operation, and the lowest possible pilot fuel, for example by injection of pilot fuel oil into the pre-chamber. Includes a pilot fuel oil system optimized for ammonia to oil ratio ignition. Additionally, some known dual fuel engines also use a full ratio fuel oil injection system for pilot fuel oil injection, where, when running on gaseous fuel, the pilot fuel oil fraction size ranges from 1.5 to 5% of the full ratio fraction.

However, existing dual-fuel concept engines, such as ammonia and fuel oil fuel engines, have the problem of being complicated in that they include a pilot fuel oil injection system. Additionally, the dual fuel concept includes that the full ratio fuel oil injection system does not operate during ammonia fuel operation. This means that there is a risk of deposits forming in the nozzle holes of the injection valves of the full ratio fuel oil injection system during ammonia fuel operation, and therefore when a switch from ammonia operation to fuel oil operation is attempted, the full ratio fuel oil injection system This means it may not work properly. Additionally, ammonia has a laminar flame speed almost 10 times lower than that of most hydrocarbons, so flame extinguishing/extinguishing can occur even at low turbulence levels, and thus full ratio fuel oil injection systems applied to known fuel oil/gas dual fuel engines. Using , ammonia combustion can be difficult to maintain because it does not ensure ignition and combustion of all ammonia fuel. The injection time of fuel oil in a pilot fuel oil injection system is typically about 1 degree of crank angle, which only ensures ignition of ammonia and does not guarantee complete combustion of all ammonia fuel.

The object of the present invention is to provide a large turbocharged two-stroke uniflow crosshead compression ignition internal combustion engine of the kind mentioned at the outset, in which the problems mentioned above are at least significantly reduced.

The foregoing objects and further objects are achieved by the features of the independent claims. Additional embodiment forms are apparent from the dependent claims, description and drawings.

According to a first aspect, a large turbocharged, two-stroke, uniflow crosshead compression ignition internal combustion engine is provided, the engine running on both an ignition fluid, such as fuel oil, and ammonia as fuel for combustion within the engine. Having at least one operating mode, the engine:

- at least one cylinder with an internally reciprocating piston and a cylinder liner and a cylinder cover covering said cylinder,

- A combustion chamber formed inside the cylinder between the reciprocating piston and the cylinder cover,

- an ammonia fuel system configured to supply pressurized ammonia to at least one ammonia fuel valve arranged in the cylinder cover or cylinder liner, and

- an ignition fluid system configured to supply pressurized ignition fluid to at least one ignition fluid valve arranged in the cylinder cover or cylinder liner.

Includes,

The ignition fluid system is characterized in that it is configured to supply ignition fluid to the combustion chamber with an injection duration of at least 20% of the determined duration of ammonia fuel combustion.

The duration of ammonia fuel combustion is determined by the engine control system depending on the actual speed of the engine.

Accordingly, a more complete combustion of ammonia is ensured by injecting the ignition fluid into the combustion chamber of the cylinder of the internal combustion engine over a longer period of time in connection with the known practice. Additionally, since a full rate fuel oil injection system can be used, the pilot fuel oil injection system can be omitted, thus saving a considerable amount of space and considerable cost for installing the fuel injection valve in the cylinder cover. Provides savings. Moreover, during dual fuel operation using both ammonia and an ignition fluid such as fuel oil, the fuel oil injection system also continues to run and thus remains clean and ready to switch from ammonia dual fuel operation to fuel oil operation.

To ensure a higher, preferably complete ammonia combustion rate, the ignition fluid system has an injection duration of at least 50%, preferably at least 80%, and most preferably at least 95% of the determined ammonia fuel combustion duration. It may be configured to supply ignition fluid to the combustion chamber.

The ignition fluid system may be configured to supply ignition fluid to the combustion chamber with an injection duration increasing from 2 degrees of crank angle at low engine speeds to 20 degrees of crank angle at full rate engine speed. Low engine speed in this context is defined as the lowest possible engine speed.

The ignition fluid system may be configured to supply ignition fluid to the combustion chamber continuously or intermittently during the injection duration. If the ignition fluid system is configured for intermittent injection, the number of injections may be predetermined from 2 to 10 injections, preferably 5 injections, or may be varied, such as cylinder pressure, which indicates combustion performance and thus combustion of ammonia. This can be determined by a control system that monitors various engine operating parameters.

The ignition fluid system ranges from 5 to 50%, preferably 15 to 40%, and most preferably 25 to 35% of the amount required at full speed rate when operated with ignition fluid such as fuel oil alone. It may be configured to supply ignition fluid to the combustion chamber in an amount of.

The ammonia fuel system may be configured to supply ammonia to the combustion chamber in an amount of at least 60%, preferably at least 70%, and most preferably at least 95% of the amount of fuel required for full speed operation of the engine. Reducing the size of the ammonia fuel system also reduces costs accordingly.

In one embodiment of the invention, the ammonia fuel valve may be connected to a pre-chamber connected to the combustion chamber by an opening. Therefore, by injecting ammonia fuel into the combustion chamber through such a pre-chamber, significant deceleration of the fuel is caused before it enters the combustion chamber from the opening, and the pre-chamber can also function as a preheating chamber. Therefore, when the fuel enters the combustion chamber through the opening, the speed of the fuel decreases and the temperature of the fuel increases when it enters the combustion chamber, thereby at least partially overcoming the problems with ammonia as a fuel for compression ignition internal combustion engines mentioned above.

In this embodiment of the invention, the ignition fluid valve of the engine may be coupled to a pre-chamber, the ignition fluid valve having an ignition fluid nozzle with a nozzle orifice, and the ignition fluid valve connected to a source of pressurized ignition fluid. Therefore, the ignition fluid can be mixed with ammonia in the pre-chamber to improve stable ignition of ammonia. By injecting the ignition fluid into the pre-chamber at high pressure, it is ensured that the ignition fluid is well dispersed in the ammonia and that the ignition fluid is already well mixed with the ammonia when the mixture enters the combustion chamber.

The pre-chamber can be formed in an insert arranged in the cylinder cover. Therefore, if the pre-chamber or the opening between the pre-chamber and the combustion chamber is damaged, the pre-chamber can be easily replaced by replacing the insert without having to work (process) the entire cylinder cover.

Additionally, the pre-chamber can be formed together with the ammonia fuel valve as a single unit, where this single unit is an insert arranged in the cylinder cover. Therefore, the pre-chamber and ammonia fuel valve can be installed in the cylinder cover in a single operation.

According to a second aspect, a method of operating a large turbocharged, two-stroke, uniflow crosshead compression ignition internal combustion engine is provided, the engine comprising both an ignition fluid such as fuel oil and ammonia as fuel for combustion within the engine. Having at least one operating mode in which the engine operates in all:

- at least one cylinder with an internally reciprocating piston and a cylinder liner and a cylinder cover covering said cylinder,

- A combustion chamber formed inside the cylinder between the reciprocating piston and the cylinder cover,

- an ammonia fuel system configured to supply pressurized ammonia to at least one ammonia fuel valve arranged in the cylinder cover or cylinder liner, and

- an ignition fluid system configured to supply pressurized ignition fluid to at least one ignition fluid valve arranged in the cylinder cover or cylinder liner.

Includes,

The method is characterized in that the ignition fluid is supplied to the combustion chamber with an injection duration of at least 20% of the determined duration of ammonia fuel combustion.

The invention will be explained in more detail with reference to exemplary embodiments shown in the following drawings:
1 shows a front view of a large two-stroke diesel engine according to an exemplary embodiment;
Figure 2 shows a side view of the large two-stroke engine of Figure 1;
Figure 3 shows a schematic diagram of the large two-stroke engine according to Figure 1;

In the detailed description that follows, the compression ignition internal combustion engine according to the invention will be described with reference to a large two-stroke uniflow scavenging internal combustion engine with a crosshead, but it should be understood that the internal combustion engine may be of other types.

1, 2 and 3 show a large, low-speed turbocharged two-stroke diesel engine with a crankshaft (8) and a crosshead (9). Figure 3 shows a schematic diagram of a large low-speed turbocharged two-stroke diesel engine with intake and exhaust systems. In this exemplary embodiment, the engine has six cylinders 1 in line. Large, low-speed turbocharged two-stroke diesel engines typically have four to fourteen cylinders (1) in a row, supported by a cylinder frame (23), which is supported by an engine frame (11). These engines are used, for example, as main engines in marine vessels or as stationary engines to operate generators in power plants. The total output of the engine may range, for example, from 1,000 to 110,000 kW.

In this exemplary embodiment the engine has a scavenging port 18 in the lower section of the cylinder liners 1 and a central exhaust valve 4 on the top of each cylinder liner 1 with dual fuel compression of the two stroke uniflow type. It is an ignition type engine. The engine has at least one mode of operation, operating with both ammonia or ammonia-based fuel and an ignition fluid such as fuel oil. The engine may further have at least one conventional fuel mode in which the engine operates on conventional fuel, such as fuel oil (marine diesel) or heavy fuel oil.

During engine operation, scavenge air passes from the scavenge air receiver (2) to the scavenge port (18) of the individual cylinder (1). The piston 10, which reciprocates between bottom dead center (BDC) and top dead center (TDC) within the cylinder liner 1, compresses the scavenge air. Fuel in the form of ammonia and ignition fluid is injected into the combustion chamber of the cylinder liner 1 through fuel valves 50 arranged on the cylinder cover 22. Ammonia and ignition fluid are supplied from the ammonia fuel supply system 30 and the ignition fuel supply system 40, respectively. Injection of ammonia may occur during the stroke of the piston 10 towards TDC at relatively low pressure, or at or near TDC at relatively high pressure. Injection of ignition fluid always occurs at high pressure at or near TDC. Combustion follows, and exhaust gases are produced. Each cylinder cover 22 is equipped with two or more fuel valves 50. The fuel valves 50 may be configured to each inject only one specific type, i.e. ammonia and in this case ignition fluid, and thus two for injecting ignition fluid, for example in the form of conventional fuel into the combustion chamber. There will be more than two fuel valves 50 and two or more fuel valves 50 for injecting ammonia. Accordingly, the engine will have four or more fuel valves 50. There may be two or more fuel valves 50 for each cylinder if the fuel valves 50 are premixed or suitable for injecting both ammonia and conventional fuel simultaneously through separate nozzle orifices. Fuel valves 50 are arranged in the cylinder cover 22 around the central exhaust valve 4 . The ignition fluid is, for example, dimethyl ether (DME) or fuel oil, but may also be another type of ignition accelerator, such as hydrogen. Because the engine is a dual fuel engine, the engine may be operated in conventional fuel mode, where the engine may be operated only with conventional fuels such as ignition fluid such as fuel oil (marine diesel) or heavy fuel oil. In one embodiment, the ammonia fuel valve 50' is arranged along the cylinder liner (shown as interrupted lines) and the piston 10 passes the ammonia fuel valve 50' on its way from BDC to TDC. Before this, ammonia fuel is introduced into the cylinder liner (1) at a relatively low pressure. Therefore, the piston 10 compresses the mixture of scavenging air and fuel. Timed ignition at or near TDC is triggered by ignition fluid injection. The pressure at which fuel is injected in embodiments with the ammonia fuel valve 50' is substantially lower than the pressure at which fuel is injected in embodiments where the fuel valve 50' is located in the cylinder cover 22. Accordingly, the pressure required for the ammonia fuel supply system 30 to deliver fuel can be significantly lower and/or the pressure booster often used in the fuel valve 50 located in the cylinder cover can be avoided.

When the exhaust valve (4) is opened, the exhaust gases flow to the exhaust gas receiver (3) through the exhaust duct connected to the cylinder and through the first exhaust conduit (19) to the turbocharger via the selective catalytic reduction (SCR) reactor (38). It flows to the turbine (6) of the charger (5), from where the exhaust gases flow through the second exhaust duct via the economizer (20) to the outlet (21) and into the atmosphere. SCR reactors reduce emissions, especially NO _x emissions.

Via the shaft, the turbine 6 drives the compressor 7, from which fresh air is supplied through the air inlet 12. The compressor (7) delivers pressurized scavenging air to the scavenging air conduit (13) leading to the scavenging air receiver (2). The scavenge air in the scavenge air conduit 13 passes through an intercooler 14 to cool the scavenge air.

The cooled scavenging air passes via an auxiliary blower (16) driven by an electric motor (17), which prevents the compressor (7) of the turbocharger (5) from delivering sufficient pressure for the scavenging air receiver (2). When not operating, i.e. under low or partial engine load conditions, the scavenge air flow is pressurized. At higher engine loads, the compressor 7 of the turbocharger delivers enough compressed scavenging air, so that the auxiliary blower 16 is bypassed via the non-return valve 15 and the electric motor 17 is deactivated.

Ammonia is supplied to the ammonia valve 50 at a substantially stable pressure and temperature, and may be supplied to the ammonia valve 50 in liquid or gaseous form. The ammonia liquid may be aqueous ammonia (ammonia-water combination).

According to the invention, the ignition fluid is injected into the combustion chamber of the cylinder of the internal combustion engine over a longer period of time in accordance with known practice, whereby a more complete combustion of the ammonia is obtained. According to known practice, the ignition fluid is injected over a crank angle of about 1 degree, corresponding to 5 to 10% of the ammonia fuel combustion period. However, according to the present invention, the ignition fluid system 40 is configured to supply ignition fluid to the combustion chamber with an injection duration of at least 20% of the determined duration of ammonia fuel combustion.

Besides more complete combustion of ammonia, a further advantage of the present invention is that since the required amount of ignition fluid is used, a full rate fuel oil injection system can be used for injection of the ignition fluid. This means that the pilot fuel oil injection system can be omitted, providing significant cost savings and better space for installing the fuel injection valve in the cylinder cover. Moreover, the fuel oil injection system operates continuously in all operating modes of the engine and therefore remains clean.

In order to produce as little CO ₂ as possible by engine operation in which both ammonia and ignition fluid are burned simultaneously, the amount of ignition fluid must be kept as low as possible without impairing ammonia combustion. However, in some situations, the ignition fluid must be injected into the combustion chamber with an injection duration of at least 50%, even at least 80% or at least 95% of the determined combustion duration of the ammonia fuel combustion to ensure complete combustion of the ammonia. Additionally, the ignition fluid may need to be injected into the combustion chamber with an injection duration of 100% of the determined ammonia fuel combustion duration.

The ignition fluid system 40 may be configured to supply ignition fluid to the combustion chamber with an injection duration increasing from a crank angle of approximately 2 degrees at low engine speeds to a crank angle of approximately 20 degrees at full rate engine speed.

The ignition fluid system may be configured to supply ignition fluid to the combustion chamber continuously or intermittently during the injection duration. If the ignition fluid system is configured for intermittent injection, the number of injections may be predetermined to be from 2 to 10 injections, preferably 5 injections, or may be determined by various parameters, such as cylinder pressure, which dictates combustion performance and thus combustion of ammonia. It may be determined and variable by a control system that monitors engine operating parameters.

The ignition fluid system ranges from 5 to 50%, preferably 15 to 40%, and most preferably 25 to 35% of the amount required for full speed rate when operated with ignition fluid such as fuel oil alone. It may be configured to supply ignition fluid to the combustion chamber in an amount of .

The ammonia fuel system may be configured to supply ammonia to the combustion chamber in an amount of at least 60%, preferably at least 70%, and most preferably at least 95%. Reducing the size of the ammonia fuel system also reduces costs accordingly.

Claims (10)

A large turbocharged two-stroke Uniflow crosshead compression ignition internal combustion engine,
The engine has at least one mode of operation operating with both ammonia and an ignition fluid such as fuel oil as fuel for combustion within the engine, wherein the engine:
- at least one cylinder with an internally reciprocating piston (10) and a cylinder liner (1) and a cylinder cover (22) covering the cylinder,
- A combustion chamber formed inside the cylinder between the reciprocating piston (10) and the cylinder cover (22),
- an ammonia fuel system (30) configured to supply pressurized ammonia to at least one ammonia fuel valve (50) arranged on the cylinder cover (22) or the cylinder liner (1), and
- an ignition fluid system (40) configured to supply pressurized ignition fluid to at least one ignition fluid valve (50) arranged on the cylinder cover (22) or the cylinder liner (1)
Includes,
The engine according to claim 1, wherein the ignition fluid system (40) is configured to supply ignition fluid to the combustion chamber with an injection duration of at least 20% of the determined duration of ammonia fuel combustion. In claim 1,
The ignition fluid system (40) is configured to supply ignition fluid to the combustion chamber with an injection duration of at least 50%, preferably at least 80%, and most preferably at least 95% of the determined duration of ammonia fuel combustion. Featured engine. In claim 1,
The ignition fluid system 40 is configured to supply ignition fluid to the combustion chamber with an injection duration increasing from a crank angle of 2 degrees at low engine speeds to a crank angle of 20 degrees at full rate engine speed. engine that does. The method of claim 1, 2 or 3,
The engine, characterized in that the ignition fluid system (40) is configured to continuously supply ignition fluid to the combustion chamber over the injection duration. The method of claim 1, 2 or 3,
The ignition fluid system (40) is configured to intermittently supply ignition fluid to the combustion chamber during the injection duration. In claim 5,
The ignition fluid system 40 is configured for intermittent injection,
The number of injections is predetermined from 2 to 10 injections, preferably 5 injections, or
An engine characterized by variable and determined by a control system that monitors various engine operating parameters, such as cylinder pressure, which indicates combustion performance and thus combustion of ammonia. The method of any one of claims 1 to 6,
The ignition fluid system 40 is 5 to 50%, preferably 15 to 40%, and most preferably 25% of the amount required for full speed rate when operated only with ignition fluid such as fuel oil. An engine characterized in that it is configured to supply ignition fluid to the combustion chamber in an amount ranging from 35% to 35%. The method of any one of claims 1 to 7,
The ammonia fuel system 30 supplies ammonia to the combustion chamber in an amount of at least 60%, preferably at least 70%, and most preferably at least 95% of the amount of fuel required for full speed operation of the engine. An engine characterized in that it is configured to do so. A method of operating a large turbocharged two-stroke Uniflow crosshead compression ignition internal combustion engine, comprising:
The engine has at least one mode of operation operating with both ammonia and an ignition fluid such as fuel oil as fuel for combustion within the engine, wherein the engine:
- at least one cylinder with an internally reciprocating piston (10) and a cylinder liner (1) and a cylinder cover (22) covering the cylinder,
- A combustion chamber formed inside the cylinder between the reciprocating piston (10) and the cylinder cover (22),
- an ammonia fuel system (30) configured to supply pressurized ammonia to at least one ammonia fuel valve (50) arranged on the cylinder cover (22) or the cylinder liner (1), and
- an ignition fluid system (40) configured to supply pressurized ignition fluid to at least one ignition fluid valve arranged in the cylinder cover or in the cylinder liner (1)
Includes,
wherein the ignition fluid is supplied to the combustion chamber with an injection duration of at least 20% of the determined duration of ammonia fuel combustion. In claim 9,
characterized in that the ignition fluid is supplied to the combustion chamber with an injection duration of at least 50%, preferably at least 80%, most preferably at least 95% of the determined duration of ammonia fuel combustion.