KR20220081922A - Internal combustion engine - Google Patents

Abstract

A two-stroke uniflow scavenge crosshead internal combustion engine comprising at least one cylinder, a cylinder cover, a piston, a fuel gas supply system connectable to a fuel gas tank, and a scavenging air system, wherein the cylinder has a cylinder wall and the cylinder cover A two-stroke uniflow scavenging crosshead internal combustion engine having an exhaust valve arranged on top of a cylinder is disclosed. The fuel gas supply system includes, with respect to the cylinder, a fuel gas valve arranged at least partially in a cylinder wall. The fuel gas valve includes a valve shaft extending along a valve axis, a valve plate, and a valve seat, the valve shaft and the valve plate being movable along the valve axis between an open position and a closed position. The fuel gas valve is configured such that the valve shaft and the valve plate move in an upstream direction when moving from the closed position to the open position.

Description

internal combustion engine {INTERNAL COMBUSTION ENGINE}

The present invention relates to a two-stroke internal combustion engine and a fuel gas valve.

Two-stroke internal combustion engines are being used as propulsion engines in ships such as container ships, bulk carriers and oil tankers. The reduction of unwanted emissions from internal combustion engines is becoming increasingly important.

An effective way to reduce the amount of unwanted exhaust gases is the conversion from fuel oils such as heavy fuel oil (HFO) to fuel gases, for example. The fuel gas may be injected into the cylinder at the end of the compression stroke, where it may be ignited immediately by the high temperature the gas in the cylinder reaches during compression or by ignition of the pilot fuel. However, injecting fuel gas into the cylinder at the end of the compression stroke requires a high pressure gas compressor to compress the fuel gas prior to injection to overcome the large pressure in the cylinder.

However, high pressure gas compressors are expensive and complicated to manufacture and maintain. One way to avoid the need for such a high pressure compressor is to have a fuel gas valve configured to inject fuel gas at the beginning of the compression stroke when the pressure in the cylinder is significantly lower.

Patent document EP 3015679 discloses such a fuel gas valve. The fuel gas valve includes a valve shaft, a valve plate, and a valve seat, wherein the valve shaft and the valve plate are movable between an open position and a closed position, wherein in the open position the valve plate is inserted into a gas fuel nozzle connected to the fuel gas valve. is extended

However, low-pressure two-stroke uniflow scavenge internal combustion engines have the problem of gas slip. This is problematic because commonly used fuel gases are powerful greenhouse gases. Methane, for example, is a greenhouse gas, potentially 84 times more potent than CO2. Thus, even a small gas slip will have a significant environmental impact over the life of the engine, especially if the gas slip is repeated for each engine cycle. Controlling the timing of the exhaust and fuel gas valves can limit the amount of gas slip, but only to a certain extent.

Accordingly, further reduction of gas slip remains a problem.

According to a first aspect, the present invention relates to a two-stroke uniflow scavenging crosshead internal combustion engine comprising at least one cylinder, a cylinder cover, a piston, a fuel gas supply system connectable to a fuel gas tank, and a scavenging air system. wherein the cylinder has a cylinder wall, the cylinder cover is arranged on top of the cylinder and has an exhaust valve, the piston is movably arranged in the cylinder along a central axis between bottom dead center and top dead center, and the scavenge air system having a scavenging air inlet arranged at the bottom, wherein the fuel gas supply system is arranged at least partially in the cylinder wall relative to the cylinder and is configured to introduce fuel gas into the cylinder through the fuel gas nozzle during a compression stroke so that the fuel gas is scavenge a fuel gas valve capable of mixing with the scavenging air from the air inlet and allowing the mixture of the scavenging air and fuel gas to be compressed prior to ignition, the fuel gas valve comprising a valve shaft extending along a valve axis, a valve plate, and a valve seat, wherein the valve shaft and the valve plate are movable along a valve axis between an open position and a closed position, wherein the fuel gas valve moves in an upstream direction when the fuel gas valve moves from the closed position to the open position. is configured to

After the fuel gas valve closes and the piston moves past the fuel gas nozzle, a residual volume of fuel gas is captured at the fuel gas nozzle. A portion of this residual volume will flow/diffusion into the scavenging space below the piston, where it will mix with the scavenging air. In the next engine cycle, as the piston moves down the scavenging air inlet, the mixture will flow into the cylinder and some of the mixture will be sent directly out of the exhaust valve at the start of the scavenging process, causing gas slip.

Consequently, by reversing the lift direction of the fuel gas valve, the internal volume of the fuel gas nozzle can be reduced because it is no longer necessary to receive the valve plate when the valve shaft and the valve plate are in the open position. Accordingly, the residual volume of the fuel gas remaining in the fuel gas nozzle when the valve is closed can also be reduced, which may result in reducing the amount of gas slip. Reduced gas slip leads to a corresponding increase in efficiency.

The internal combustion engine is preferably a uniflow scavenging, large, low-speed turbocharged, two-stroke crosshead internal combustion engine for propulsion of ships with a power of at least 400 kW per cylinder. The internal combustion engine may include a turbocharger that is driven by exhaust gases produced by the internal combustion engine and is configured to compress scavenging air. The internal combustion engine may be a dual-fuel engine having an auto cycle mode when running on fuel gas and a diesel cycle mode when running on an alternative fuel such as heavy oil or marine diesel oil. Such dual-fuel engines have a dedicated fuel supply system for injecting the alternative fuel, which also prevents the injection of pilot fuel when operating in auto cycle mode to ignite a mixture of fuel gas and scavenging air. may be used.

An internal combustion engine may include a dedicated ignition system such as a pilot fuel system capable of injecting precisely metered small amounts of pilot fuel, eg heavy oil or marine diesel oil, so that only the required amount of pilot fuel is used, between fuel gas and scavenging air. The mixture may ignite. Such pilot fuel systems are much smaller in size than dedicated fuel supply systems for alternative fuels and are better suited to injecting the correct amount of pilot fuel, and dedicated fuel supply systems for alternative fuels have larger components due to their oversized components. It is not suitable for this purpose.

The pilot fuel may be injected into a pre-chamber fluidly connected to a combustion chamber of an internal combustion engine. Alternatively, the mixture of fuel gas and scavenging air may be ignited by means comprising a spark plug or laser igniter. Each cylinder may have one or more scavenging air inlets at the bottom of the cylinder and an exhaust outlet at the top of the cylinder.

The valve shaft and valve plate can move in an upstream direction by moving along the valve axis away from the center of the cylinder when moving from the closed position to the open position. Correspondingly, the valve shaft and valve plate can move in a downstream direction by moving along the valve axis towards the center of the cylinder when moving from the open position to the closed position. The valve axis may correspond to a radial direction so that the valve shaft and valve plate can move directly away from the center of the cylinder when moving from the closed position to the open position. However, the valve axis may be inclined with respect to the radial direction.

The valve plate may have a first side and a second side, the second side opposite the first side, the valve shaft extending from the first side and a portion of the second side portion of the valve seat when the valve is in the closed position. adjacent to

In some embodiments, the fuel gas valve is configured to inject fuel gas into the cylinder during a compression stroke between 0 degrees and 160 degrees from bottom dead center, or between 0 degrees and 130 degrees from bottom dead center, or between 0 degrees and 90 degrees from bottom dead center. .

Examples of fuel gas include natural gas, methane, ethane, liquefied petroleum gas and ammonia.

In some embodiments the fuel gas nozzle is an integral part of the fuel gas valve.

Consequently, by integrating the fuel gas nozzle into the fuel gas valve, the number of engine parts is reduced and the engine becomes simpler.

In some embodiments the fuel gas valve includes a valve housing, the valve housing includes a first portion and a second portion, the fuel gas nozzle and the valve seat are formed in a second portion of the valve housing, the second portion of the valve housing The first part and the second part of the valve housing are connected upstream of the valve seat.

As a result, it can be easier to detect a gas leak from the connection between the first and second parts of the valve housing, which means that when the fuel gas valve is closed, the gas leak from the connection is upstream of the fuel gas valve. This will result in a pressure drop in , which can be detected by the sensor as described below.

In some embodiments the fuel gas supply system further comprises a safety valve arranged upstream of the fuel gas valve, the fuel gas valve being fluidly connectable to the fuel gas tank via the safety valve.

In some embodiments the safety valve is configured to open before the fuel gas valve is configured to open and to close after the fuel gas valve is configured to close such that a limited period of time is allowed for fuel gas to flow through the safety valve to the fuel gas valve. create

In some embodiments the first sensor is arranged in a space between the safety valve and the fuel gas valve, wherein the first sensor detects, directly or indirectly, a pressure change in the space between the fuel gas valve and the safety valve indicative of a failed fuel gas valve. is configured to

Consequently, it becomes possible in a reliable way to detect failures of different types of fuel gas valves.

The first sensor may be a pressure sensor configured to directly detect a change in pressure. Alternatively, the first sensor may be another sensor configured to indirectly detect a change in pressure, such as a temperature sensor. The second sensor may be further arranged in the space between the safety valve and the fuel gas valve, for example, the first sensor may be a pressure sensor and the second sensor may be a temperature sensor. The internal combustion engine may further comprise a control unit operably connected to the first sensor (and possibly also to the second sensor). The control unit monitors the sensor signal received from the first sensor so that if a malfunctioning fuel gas valve is detected, the safety valve and the one or more fuel gas valves, indicating, for example, damage to the valve plate or valve seat or clogging of the valve shaft. It may be configured to issue an alarm when a drop in pressure in the space with the first population is detected. The control unit is configured to take action in response to the alarm, eg, the control unit may permanently close a safety valve of a failed fuel gas valve and/or operate a blow to evacuate fuel gas from the fuel gas supply system. and/or control the engine to switch the gas mode to an alternate mode, such as diesel mode.

In some embodiments the safety valve has a valve housing having an inlet and an outlet, and the fuel gas valve has a valve housing having an inlet and an outlet, wherein the valve housing of the safety valve is directly connected to the valve housing of the fuel gas valve to ensure safety The outlet of the valve is directly connected to the inlet of the first fuel gas valve.

As a result, the volume of gas between the safety valve and the fuel gas valve can be small. This can reduce the amount of fuel gas that can be released uncontrollably into the cylinder if the fuel gas valve malfunctions. If a small amount of fuel gas is trapped between the fuel gas valve and the safety valve, it is easier to detect the leaking fuel gas valve because the resulting pressure drop will be greater.

In some embodiments a safety valve includes a valve shaft extending along a valve axis, a valve plate, and a valve seat, the valve shaft and valve plate being movable along the valve axis between an open position and a closed position, wherein the safety valve The valve is configured such that the valve shaft and the valve plate move in a downstream direction when moving from the closed position to the open position.

When the pressure inside the cylinder increases above the closing pressure of the fuel gas valve, the fuel gas valve is designed to have a reverse lift direction and is forcibly opened. However, by using the safety valve with a normal lift direction, it can be ensured that the safety valve is not forcibly opened, since in such a situation the valve plate of the safety valve will be pressed harder against the valve seat.

A valve plate of the safety valve may have a first side and a second side, the second side opposite the first side, the valve shaft extending from the first side and a portion of the first second side at which the safety valve is closed abuts the valve seat when in position.

In some embodiments the fuel gas nozzle extends along a nozzle axis and has an inlet for receiving fuel gas and an outlet for passing fuel gas into the cylinder, wherein when moving from a closed position to an open position, the valve shaft and valve plate Traveling a distance d1 along the valve axis, wherein the fuel gas nozzle has a cross-sectional area less than the cross-sectional area of the valve plate at a distance d1 from the inlet along the nozzle axis.

As a result, the residual volume of the fuel gas trapped in the fuel gas nozzle can be lowered, and thus the gas slip can be correspondingly lowered.

In some embodiments the valve plate has a first side and a second side, the valve shaft extending from the first side and the second side facing the outlet of the fuel gas nozzle, wherein the fuel gas valve is the second side of the valve plate It further includes a gas displacement element extending from the fuel gas nozzle into the fuel gas nozzle.

As a result, the residual volume of the fuel gas trapped in the fuel gas nozzle can be further lowered, and thus the gas slip can be correspondingly lowered.

The gas displacement element may taper towards its distal end to allow the fuel gas nozzle to decrease in width towards the outlet.

According to a second aspect the present invention relates to a fuel gas valve for a two-stroke uniflow scavenge crosshead internal combustion engine as disclosed in relation to the first aspect, wherein the fuel gas valve comprises a valve shaft extending along a valve axis; a valve plate, and a valve seat, wherein the valve shaft and the valve plate are movable along a valve axis between an open position and a closed position, wherein the fuel gas valve causes the valve shaft and the valve plate to move from the closed position to the open position. configured to move in an upstream direction.

Different aspects of the present invention may be embodied in different ways, including a two-stroke uniflow scavenge crosshead internal combustion engine and fuel gas valve, as described above and below, and may be embodied in different ways as described in connection with at least one aspect described above. Each has one or more preferred embodiments which each provide one or more advantages and advantages and correspond to preferred embodiments described in connection with at least one of the aspects set forth above and/or in the dependent claims. Furthermore, it will be understood that an embodiment described in connection with one of the aspects described herein may be equally applicable to another aspect.

The above and/or additional objects, features and advantages of the present invention will become more apparent by the following illustrative and non-limiting detailed description of embodiments of the present invention with reference to the accompanying drawings.
1 schematically shows a cross-section of a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention;
2 and 2B schematically show a cross-section of a conventional fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine.
3A and 3B schematically show a cross-section of a fuel gas valve for a two-stroke uniflow scavenge crosshead internal combustion engine according to an embodiment of the present invention.
4 schematically shows a cross-section of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention.
5 schematically shows a cross-section of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention.
6 shows a schematic diagram of a valve assembly for a fuel gas supply system of a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention;

In the following description, reference is made to the accompanying drawings, which show by way of illustration how the invention may be embodied.

1 schematically shows a cross-section of a two-stroke uniflow scavenge crosshead internal combustion engine (hereinafter also referred to as a two-stroke internal combustion engine) 100 for propulsion of marine vessels according to an embodiment of the present invention. The two-stroke internal combustion engine 100 includes a scavenging air system 111 , an exhaust gas receiver 108 and a turbocharger 109 . A two-stroke internal combustion engine has a plurality of cylinders 101 (only a single cylinder is shown in the cross-sectional view). Each cylinder 101 has a scavenging air inlet 102 arranged at the bottom of the cylinder for providing scavenging air, a piston 103, a cylinder cover 113 arranged on the upper part of the cylinder, and a cylinder cover ( an exhaust valve 104 arranged at 113 , and one or more fuel gas valves 105 (shown only schematically). The scavenging air inlet 102 is fluidly connected to the scavenging air system. The piston 103 is shown in its lowest position (bottom dead center). The piston 103 has a piston rod connected to a crankshaft (not shown). The piston 103 is arranged movably in the cylinder along a central axis 114 between bottom dead center and top dead center. The fuel gas valve 105 is only schematically shown. A fuel gas valve (105) is arranged at least partially within the cylinder wall between the cylinder cover (113) and the scavenging air inlet (102) and forms part of a fuel gas supply system, for introducing fuel gas into the cylinder during a compression stroke. wherein the fuel gas is capable of mixing with the scavenging air from the scavenging air inlet 102 and is configured to allow the mixture of the scavenging air and fuel gas to be compressed prior to ignition, the fuel gas valve 105 having a fuel gas nozzle; The fuel gas nozzle has one or more nozzle outlets for providing fuel gas to the interior of the cylinder. The fuel gas supply system is fluidly connected to the fuel gas tank. The fuel gas supply system may further include a safety valve (not shown) for each cylinder, wherein the fuel gas valve 105 is fluidly connected to the fuel gas tank via the safety valve. The safety valve 112 is configured to open for a short time before the fuel gas valve 105 is configured to open and to close for a short time after the fuel gas valve 105 is configured to close, so that the fuel gas from the main fuel gas supply tube is This creates a limited time to flow through the safety valve to the fuel gas valve 105 . This means that in normal operation the safety valve will actuate as often as the fuel gas valve, as it opens and closes, respectively, immediately before and immediately after the opening period of the gas valve 105 as gas is introduced into the cylinder.

The internal combustion engine 100 includes a dedicated ignition system for igniting a mixture of fuel gas and scavenging air at the end of the compression stroke. For example, a dedicated ignition system could be a pilot fuel system capable of injecting precisely metered small amounts of pilot fuel, such as heavy oil or marine diesel oil, to precisely quantify a mixture of fuel gas and scavenging air to ignite a mixture of fuel gas and scavenging air. Measure and use only the required amount of pilot fuel. Such pilot fuel systems are much smaller in size and more suitable for injecting precise amounts of pilot fuel compared to dedicated fuel supply systems for alternative fuels that are not suitable for this purpose due to their oversized components. The pilot fuel may be injected into a pre-chamber that is fluidly connected to a combustion chamber of an internal combustion engine. Alternatively, the pilot fuel may be injected into a set of pre-chambers that are fluidly connected to the combustion chamber of the internal combustion engine.

The fuel gas valve 105 injects fuel gas into the cylinder 101 at the beginning of the compression stroke of 0 degrees to 130 degrees from the bottom dead center, that is, when the crankshaft is rotated 0 degrees to 130 degrees from the orientation at the bottom dead center. can be configured to Preferably, the crankshaft shaft rotates several degrees from bottom dead center so that the piston can pass the scavenge air inlet 102 to prevent fuel gas from escaping through the exhaust valve 104 and the scavenging air inlet 102 . After that, the fuel gas valve 105 may be configured to start fuel gas injection. The scavenge air system 111 includes a scavenge air receiver 110 and an air cooler 106 . The exhaust valve is centrally arranged in the cylinder cover, and the timing of the exhaust valve can be varied so that closing and/or opening of the exhaust valve can be optimized, for example to control the compression ratio and/or the temperature in the cylinder. The fuel gas valve 105 includes a valve shaft extending along a valve axis, a valve plate, and a valve seat, the valve shaft and valve plate being movable along the valve axis between an open position and a closed position. The fuel gas valve 105 is configured such that the valve shaft and the valve plate move in an upstream direction when moving from the closed position to the open position.

2a and 2b schematically show a cross-section of a conventional fuel gas valve 200 for a two-stroke internal combustion engine. The fuel gas valve 200 includes a fuel gas nozzle 204 having a valve shaft 201 , a valve plate 202 , a valve seat 203 , and a nozzle outlet 206 . The valve shaft 201 and the valve plate 202 have a closed position where fuel gas is prevented from flowing through the fuel gas valve 200 and an open position where fuel gas is allowed to flow through the fuel gas valve 200 . It is possible to move between positions. The valve shaft 201 and valve plate 202 are shown in a closed position in FIG. 2A and an open position in FIG. 2B . The valve shaft 201 and the valve plate 202 are movable between a closed position and an open position by an actuator (not shown) controlled by a control unit (not shown). The valve shaft 201 and the valve plate 202, when moving from the closed position to the open position, move in a downstream direction towards the nozzle outlet 206, so that the fuel gas nozzle 204 moves the valve plate to the open position. It should be designed to have a volume 210 in front of the valve plate 202 that is large enough to accommodate the valve plate when present. However, after the fuel gas valve closes and the piston 103 moves past the fuel gas nozzle 206 , a significant residual volume of fuel gas is trapped in the fuel gas nozzle volume 210 . A portion of this residual volume will flow/diffusion into the scavenging space below the piston 103 where it will mix with the scavenging air. In the next engine cycle, as the piston moves down the scavenging air inlet, the mixture will flow into the cylinder and a portion of the mixture will be sent directly out of the exhaust valve 104 at the start of the scavenging process, resulting in gas slippage.

3A and 3B schematically show a cross-section of a fuel gas valve 300 for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention. The fuel gas valve 300 includes a fuel gas nozzle having a valve shaft 301 extending along a valve axis 307 , a valve plate 302 , a valve seat 303 , and a nozzle outlet 306 opening into a cylinder. 304). The valve shaft 301 and the valve plate 302 have a closed position where fuel gas is prevented from flowing through the fuel gas valve 300 and an open position where fuel gas is allowed to flow through the fuel gas valve 300 . It is movable along the valve axis 307 between the positions. The valve shaft 301 and the valve plate 302 are shown in a closed position in FIG. 3A and an open position in FIG. 3B . The valve plate 302 has a first side and a second side, the valve shaft 307 extending from the first side and the second side facing the fuel gas nozzle 304 . The valve shaft 301 and the valve plate 302 are movable between a closed position and an open position by an actuator (not shown) controlled by a control unit (not shown). The fuel gas valve 300 is configured such that the valve shaft 301 and valve plate 302 move in an upstream direction away from the nozzle outlet 306 when moving from the closed position to the open position. As a result, the internal volume of the fuel gas nozzle can be reduced because it is no longer necessary to accommodate the valve plate 302 when the valve shaft 301 and the valve plate 302 are in the open position, i.e., the fuel gas nozzle 304 may be designed not to have the volume 210 shown in FIGS. 2A and 2B . Accordingly, the residual volume of the fuel gas remaining in the fuel gas nozzle when the valve 300 is closed can also be reduced, which will result in reducing the amount of gas slip. Reduced gas slip will lead to a corresponding increase in efficiency. In this embodiment, the fuel gas valve 300 has a valve housing 308 constructed as a single piece, wherein the fuel gas nozzle 304 is formed in the valve housing 308 .

4 schematically shows a cross-section of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention. This fuel gas valve corresponds to the fuel gas valve shown in FIGS. 3A and 3B, and the valve housing includes a first part 309 and a second part 310, and a fuel gas nozzle 304 and a valve seat ( 303 is formed in the second part 310 of the valve housing, with the difference that the first part 309 of the valve housing and the second part 310 of the valve housing are connected upstream of the valve seat 303 .

5 schematically shows a cross-section of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention. This fuel gas valve corresponds to the fuel gas valve shown in FIG. 4 , which further includes a gas displacement element 311 extending from the second side of the valve plate 302 into the fuel gas nozzle 304 . There is a difference that As a result, the residual volume of the fuel gas trapped in the fuel gas nozzle 304 can be much lower, and thus the gas slip can be correspondingly lowered.

6 shows a cross-section of a valve assembly 690 of a fuel gas supply system for a two-stroke uniflow scavenging crosshead internal combustion engine in accordance with an embodiment of the present invention. The valve assembly 690 includes a fuel gas valve 600 and a safety valve 650 , the safety valve 650 having a valve housing 655 having an inlet 656 and an outlet 657 , the fuel gas valve 600 has a valve housing 605 having an inlet 607 and an outlet (not shown) formed in a valve nozzle 670 . The safety valve 650 includes a valve shaft 651 , a valve plate 652 , and a valve seat 653 . The valve shaft 651 and the valve plate 652 have a closed position that prevents fuel gas from flowing through the safety valve 650 and an open position that allows fuel gas to flow through the safety valve 650 . It is possible to move between The valve shaft 651 and the valve plate 652 are shown in FIG. 6 as in the closed position. The fuel gas valve 600 includes a valve shaft 601 , a valve plate 602 , and a valve seat 603 . The valve shaft 601 and valve plate 602 have a closed position that prevents fuel gas from flowing through the fuel gas valve 600 and an open position that allows fuel gas to flow through the fuel gas valve 600 . It is possible to move between positions. The valve shaft 601 and valve plate 602 are shown in FIG. 6 as in the closed position. The valve housing 655 of the safety valve is directly connected to the valve housing of the first fuel gas valve 605 , and the outlet of the safety valve 657 is directly connected to the inlet of the first fuel gas valve 607 . The valve assembly 690 further includes a pressure sensor 608 arranged in a volume between the safety valve 650 and the fuel gas valve 600 .

In addition, the valve assembly 690 may include a position sensor, such as an inductive sensor, that monitors the position of the valve shaft 601 . The advantage of using a pressure sensor over an inductive position sensor is that the pressure sensor can check not only the spindle position but also the tightness of the entire valve assembly. Furthermore, a single pressure sensor can simultaneously monitor the functions of both the fuel gas valve and the safety valve. The method using position sensors requires two separate sensors to monitor the two valves. The valve housing 605 of the fuel gas valve includes a first portion 609 and a second portion 610 , the fuel gas nozzle and the valve seat 603 are formed in the second portion of the valve housing 610 , A first portion of the valve housing 609 and a second portion of the valve housing 610 are connected upstream of the valve seat 603 . The fuel gas valve 600 is configured such that the valve shaft 601 and the valve plate 602 move in an upstream direction when moving from the closed position to the open position. The safety valve 650 is configured to move in a downstream direction (towards the inlet 607 of the fuel gas valve 600 ) when the valve shaft 651 and the valve plate 652 move from the closed position to the open position. As a result, when the pressure inside the cylinder increases above the closing pressure of the fuel gas valve 600 , the fuel gas valve 600 will be forcibly opened because it is designed in an inverted lift direction. However, by using the safety valve 650 in the normal lift direction, since the valve plate 652 of the safety valve will be pressed harder against the valve seat 653 in such a situation, the safety valve It can be guaranteed that it is not forcibly opened.

While some embodiments have been described and shown in detail, the invention is not limited thereto, but may be embodied in other ways within the scope of the subject matter defined in the claims that follow. In particular, it is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention.

In the device claim enumerating several means, some of these means may be embodied by one and the same item of hardware. The fact that certain measures are recited in different dependent claims or described in different embodiments does not indicate that a combination of these measures cannot be used to advantage.

As used herein, the term "comprises/comprising" is used to specify the presence of a recited feature, integer, step or element, but one or more other features, integers, steps, configurations. It should be emphasized that this does not exclude the presence or addition of elements or groups thereof.

Claims (10)

A two-stroke uniflow scavenge crosshead internal combustion engine comprising at least one cylinder, a cylinder cover, a piston, a fuel gas supply system connectable to a fuel gas tank, and a scavenging air system, comprising:
The cylinder has a cylinder wall, the cylinder cover is arranged on top of the cylinder and has an exhaust valve, the piston is arranged movably in the cylinder along a central axis between bottom dead center and top dead center, and the scavenge air The system has a scavenging air inlet arranged at the bottom of the cylinder, and the fuel gas supply system, with respect to the cylinder, is arranged at least partially in the cylinder wall and delivers fuel gas into the cylinder through a fuel gas nozzle during a compression stroke. and a fuel gas valve configured to inlet such that fuel gas is mixed with the scavenging air from the scavenging air inlet and allows the mixture of the scavenging air and fuel gas to be compressed prior to ignition, the fuel gas valve being located along the valve axis. a valve shaft, a valve plate, and a valve seat extending along
wherein the fuel gas valve is arranged at least partially in the cylinder wall at a height below the piston when the piston is at top dead center, the fuel gas valve being disposed on the valve shaft and the valve when moving from the closed position to the open position. A two-stroke uniflow scavenge crosshead internal combustion engine, characterized in that the valve plate is configured to move in an upstream direction. The method according to claim 1,
wherein the fuel gas nozzle is an integral part of the fuel gas valve. 3. The method according to claim 2,
the fuel gas valve includes a valve housing, the valve housing includes a first part and a second part, the fuel gas nozzle and the valve seat are formed in a second part of the valve housing, A two-stroke uniflow scavenge crosshead internal combustion engine wherein a first portion and a second portion of the valve housing are connected upstream of the valve seat. 4. The method according to any one of claims 1 to 3,
The fuel gas supply system further comprises a safety valve arranged upstream of the fuel gas valve, the fuel gas valve being fluidly connectable to the fuel gas tank through the safety valve two-stroke uniflow scavenge crosshead internal combustion engine. 5. The method according to claim 4,
A first sensor is arranged in the space between the safety valve and the fuel gas valve, wherein the first sensor directly or indirectly detects a pressure change in the space between the fuel gas valve and the safety valve indicative of a failed fuel gas valve. A two-stroke uniflow scavenging crosshead internal combustion engine configured to detect. 6. The method of claim 4 or 5,
the safety valve has a valve housing having an inlet and an outlet, the fuel gas valve has a valve housing having an inlet and an outlet, wherein the valve housing of the safety valve is directly connected to the valve housing of the fuel gas valve and the safety valve A two-stroke uniflow scavenge crosshead internal combustion engine having an outlet directly connected to the inlet of the first fuel gas valve. 7. The method according to any one of claims 4 to 6,
The safety valve includes a valve shaft extending along a valve axis, a valve plate, and a valve seat, the valve shaft and the valve plate being movable along the valve axis between an open position and a closed position, the safety valve wherein the valve shaft and the valve plate move in a downstream direction when moving from a closed position to an open position. 8. The method according to any one of claims 1 to 7,
The fuel gas nozzle extends along a nozzle axis and has an inlet for receiving fuel gas and an outlet for delivering fuel gas into the interior of the cylinder, wherein when moving from a closed position to an open position, the valve shaft and the valve plate A two-stroke uniflow scavenge crosshead internal combustion engine moving a distance d1 along the valve axis, wherein the fuel gas nozzle has a cross-sectional area less than the cross-sectional area of the valve plate at a distance d1 from the inlet along the nozzle axis. 9. The method of any one of claims 1 to 8,
the valve plate has a first side and a second side, wherein the valve shaft extends from the first side and the second side faces an outlet of the fuel gas nozzle, the fuel gas valve is a second side of the valve plate A two-stroke uniflow scavenge crosshead internal combustion engine further comprising a gas displacement element extending from the side into the fuel gas nozzle. A fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to any one of claims 1 to 9, comprising:
the fuel gas valve includes a valve shaft extending along a valve axis, a valve plate, and a valve seat, the valve shaft and the valve plate being movable along the valve axis between an open position and a closed position;
and wherein the fuel gas valve is configured such that the valve shaft and the valve plate move in an upstream direction when moving from a closed position to an open position.

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