KR102611647B1 - Internal combustion engine - Google Patents

Abstract

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 and a cylinder cover. Disclosed is a two-stroke uniflow scavenging crosshead internal combustion engine arranged at the top of the cylinder and having an exhaust valve. The fuel gas supply system includes, for the cylinder, a fuel gas valve arranged at least partially on the cylinder wall. The fuel gas valve includes a valve shaft, a valve plate, and a valve seat extending along a valve axis, wherein the valve shaft and valve plate are moveable along the valve axis between an open position and a closed position. The fuel gas valve is configured such that the valve shaft and valve plate move in an upstream direction when moving from a closed position to an open position.

Description

Internal combustion engine {INTERNAL COMBUSTION ENGINE}

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

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

An effective way to reduce the amount of unwanted exhaust gases is the conversion from fuel oil, for example heavy fuel oil (HFO), to fuel gas. 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 reached by the gas in the cylinder upon 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 before injection to overcome the large pressure within 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 early in 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 valve plate are movable between an open position and a closed position, and in the open position, the valve plate is configured to flow into a gas fuel nozzle connected to the fuel gas valve. It is extended.

However, low-pressure two-stroke uniflow scavenging internal combustion engines have the problem of gas slip. This is a problem because commonly used fuel gases are powerful greenhouse gases. For example, methane is a greenhouse gas that is potentially 84 times more potent than CO2. Therefore, even small gas slips will result in significant environmental impacts during the life of the engine, especially if gas slips are 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.

Therefore, further reducing 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. The cylinder has a cylinder wall, the cylinder cover is arranged at the top of the cylinder and has an exhaust valve, the piston is arranged to be movable in the cylinder along the central axis between bottom dead center and top dead center, and the scavenging air system is configured to supply air to the cylinder. It has a scavenging air inlet arranged at the bottom, wherein the fuel gas supply system is arranged, relative to the cylinder, at least partially on the cylinder wall and is configured to introduce fuel gas into the cylinder through a fuel gas nozzle during the compression stroke, so that the fuel gas is scavenged. a fuel gas valve capable of mixing with scavenge air from the air inlet and allowing the mixture of scavenge air and fuel gas to be compressed prior to ignition, the fuel gas valve comprising a valve shaft extending along the valve axis, a valve plate, and It includes a valve seat, a valve shaft and a valve plate movable along the valve axis between an open position and a closed position, wherein the fuel gas valve is at least flush with the cylinder wall at a level below the piston when the piston is at top dead center. It is partially arranged, and the fuel gas valve is configured so that the valve shaft and valve plate move in the downstream direction when moving from the open position to the closed position, and the valve shaft and valve plate move in the upstream direction when moving from the closed position to the open position. The fuel gas valve is configured to prevent fuel gas from flowing past the valve plate when the valve shaft and valve plate move downstream to the closed position.

After the fuel gas valve is closed and the piston moves past the fuel gas nozzle, the residual volume of fuel gas is captured in the fuel gas nozzle. Some of this residual volume will flow/diffuse 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 a portion of the mixture will be sent directly out of the exhaust valve at the beginning of the scavenging process, causing gas slip.

As a result, by reversing the lift direction of the fuel gas valve, the internal volume of the fuel gas nozzle can be reduced because the valve shaft and valve plate no longer need to accommodate the valve plate when in the open position. Accordingly, the residual volume of fuel gas remaining in the fuel gas nozzle when the valve is closed may 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 large, low-speed, turbocharged, two-stroke, crosshead, uniflow scavenging internal combustion engine for propulsion of vessels 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 the scavenge air. The internal combustion engine may be a dual-fuel engine with an Otto cycle mode when running on fuel gas and a diesel cycle mode when running on alternative fuels such as heavy fuel oil or marine diesel oil. Such dual-fuel engines have a dedicated fuel supply system for injecting alternative fuel, which also provides injection of pilot fuel when operating in auto cycle mode to ignite the mixture of fuel gas and scavenge air. It may also be used.

Internal combustion engines may include a dedicated ignition system, such as a pilot fuel system capable of injecting small, precisely metered amounts of pilot fuel, such as heavy fuel oil or marine diesel oil, to ensure that only the required amount of pilot fuel is used. The mixture may ignite. Such pilot fuel systems are much smaller in size and better suited to injecting precise quantities of pilot fuel than dedicated fuel delivery systems for alternative fuels, due to the large size of the components. Not suitable for this purpose.

Pilot fuel may be injected into a pre-chamber fluidly connected to the combustion chamber of the internal combustion engine. Alternatively, the mixture of fuel gas and scavenge air may be ignited by means including 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, when moving from a closed position to an open position, can move in an upstream direction by moving along the valve axis away from the center of the cylinder. Correspondingly, the valve shaft and valve plate, when moving from an open position to a closed position, can move in a downstream direction by moving along the valve axis towards the center of the cylinder. The valve axis may correspond to the radial direction so that the valve shaft and valve plate can move directly away from the center of the cylinder when moving from a closed position to an open position. However, the valve axis may also be inclined with respect to the radial direction.

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

In some embodiments, the fuel gas valve is configured to inject fuel gas into the cylinder during the 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 gases include natural gas, methane, ethane, liquefied petroleum gas, and ammonia.

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

As a result, by integrating the fuel gas nozzle into the fuel gas valve, the number of engine parts is reduced, making the engine 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 the second portion of the valve housing, and the fuel gas nozzle and the valve seat are formed in 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 may be easier to detect gas leaks from the connection between the first and second parts of the valve housing, which means that when the fuel gas valve is closed, gas leaks from the connection can be detected upstream of the fuel gas valve. This is because it will result in a pressure drop in , which can be detected by a sensor as described next.

In some embodiments, the fuel gas supply system further includes a safety valve arranged upstream of the fuel gas valve, and the fuel gas valve is fluidly connectable to the fuel gas tank through 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 to provide a limited period of time during which fuel gas is allowed to flow through the safety valve to the fuel gas valve. creates .

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

As a result, it becomes possible to detect faults in different types of fuel gas valves in a reliable manner.

The first sensor may be a pressure sensor configured to directly detect pressure changes. Alternatively, the first sensor may be another sensor configured to indirectly detect pressure changes, such as a temperature sensor, for example. 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 to the second sensor). The control unit monitors the sensor signals received from the first sensor and, if a faulty fuel gas valve is detected, the safety valve and one or more fuel gas valves are activated, indicating, for example, damage to the valve plate or valve seat or blockage of the valve shaft. It may be configured to issue an alarm when a drop in pressure in the space between the first group is detected. The control unit is configured to take action in response to the alarm, for example, the control unit may permanently close the safety valve of the failed fuel gas valve and/or initiate a blow operation to expel fuel gas from the fuel gas supply system. and/or control the engine to switch from a gas mode to an alternative mode, such as a diesel mode.

In some embodiments, the safety valve has a valve housing with an inlet and an outlet, and the fuel gas valve has a valve housing with 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 provide safety protection. 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 may 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, the resulting pressure drop will be larger, making it easier to detect the leaking fuel gas valve.

In some embodiments, the safety valve includes a valve shaft, a valve plate, and a valve seat extending along a valve axis, wherein the valve shaft and valve plate are moveable 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 valve plate move in a downstream direction when moving from the closed position to the open position.

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

The 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 so that the safety valve is closed. When in position, it is adjacent to the valve seat.

In some embodiments, the fuel gas nozzle extends along the nozzle axis and has an inlet for receiving fuel gas and an outlet for delivering fuel gas into the cylinder, wherein the valve shaft and valve plate when moved from a closed position to an open position It travels a distance d1 along the valve axis, where the fuel gas nozzle has a cross-sectional area that is 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 fuel gas trapped in the fuel gas nozzle can be lowered, and 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 connected to the second side of the valve plate. It further includes a gas displacement element extending from into the fuel gas nozzle.

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

The gas displacement element may be tapered toward its distal end to allow the fuel gas nozzle to decrease in width toward the outlet.

According to a second aspect the invention relates to a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine as disclosed in connection with the first aspect, wherein the fuel gas valve comprises a valve shaft extending along the valve axis; comprising a valve plate, and a valve seat, wherein the valve shaft and valve plate are movable along the valve axis between an open position and a closed position, wherein the fuel gas valve moves the valve shaft and the valve plate when moving from the open position to the closed position. The fuel gas valve is configured to move in the downstream direction, and the valve shaft and valve plate move in the upstream direction when moving from the closed position to the open position, and the fuel gas valve is configured to allow fuel gas to flow through the valve when the valve shaft and valve plate move downstream to the closed position. It is configured to prevent flow past the plate.

Different aspects of the invention can be implemented in different ways, including a two-stroke uniflow scavenging crosshead internal combustion engine and fuel gas valve as described above and below, and described in connection with at least one aspect described above. Each provides one or more advantages and advantages and each has one or more preferred embodiments corresponding to the preferred embodiments described in relation to at least one of the aspects described above and/or in the dependent claims. Furthermore, it will be understood that embodiments described with respect to one of the aspects described herein may equally apply 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 one 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 scavenged crosshead internal combustion engine according to one 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 one embodiment of the present invention.
Figure 5 schematically shows a cross-section of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to one embodiment of the present invention.
Figure 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 one embodiment of the present invention.

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

1 schematically shows a cross-section of a 2-stroke uniflow scavenging crosshead internal combustion engine (hereinafter also referred to as a 2-stroke internal combustion engine) 100 for marine vessel propulsion according to one 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 includes a scavenging air inlet 102 arranged at the bottom of the cylinder to provide scavenging air, a piston 103, a cylinder cover 113 arranged at the top 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 scavenge air inlet 102 is fluidly connected to the scavenge 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 to be movable within the cylinder along the central axis 114 between bottom dead center and top dead center. The fuel gas valve 105 is shown only schematically. The fuel gas valve 105 is arranged at least partially within the cylinder wall between the cylinder cover 113 and the scavenge air inlet 102 and forms part of the fuel gas supply system, and introduces fuel gas into the cylinder during the compression stroke. configured to allow fuel gas to be mixed with scavenge air from a scavenge air inlet (102) and to allow the mixture of scavenge air and fuel gas to be compressed prior to ignition, wherein the fuel gas valve (105) has 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, where 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 for fuel gas to flow through the safety valve to the valve 105. This means that in normal operation the safety valve will operate as often as the fuel gas valve, opening and closing respectively immediately before and after the opening period of the gas valve 105 during which gas flows into the cylinder.

The internal combustion engine 100 includes a dedicated ignition system for igniting the mixture of fuel gas and scavenge air at the end of the compression stroke. For example, a dedicated ignition system could be a pilot fuel system capable of injecting small, precisely metered amounts of pilot fuel, such as heavy fuel oil or marine diesel oil, in precisely the right amount to ignite the mixture of fuel gas and scavenge air. Only use the measured and required amount of pilot fuel. Such pilot fuel systems are much smaller in size and better suited to injecting precise quantities of pilot fuel than dedicated fuel supply systems for alternative fuels, which are not suitable for this purpose due to the large size of the components. Pilot fuel may be injected into a pre-chamber fluidly connected to the combustion chamber of the internal combustion engine. Alternatively, 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 at 0 degrees to 130 degrees from bottom dead center, that is, when the crankshaft rotates 0 degrees to 130 degrees from the orientation at bottom dead center. It can be configured to do so. Preferably, the crankshaft axis is rotated a few degrees from bottom dead center to allow the piston to pass the scavenge air inlet 102 to prevent fuel gases from escaping through the exhaust valve 104 and the scavenge air inlet 102. After this, 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 its closing and/or opening 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, a valve plate, and a valve seat extending along a valve axis, and the valve shaft and valve plate are 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 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 valve shaft 201, a valve plate 202, a valve seat 203, and a fuel gas nozzle 204 having a nozzle outlet 206. The valve shaft 201 and 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 locations. The valve shaft 201 and valve plate 202 are shown in a closed position in Figure 2A and in an open position in Figure 2B. The valve shaft 201 and valve plate 202 are moveable between closed and open positions by an actuator (not shown) controlled by a control unit (not shown). When moving from the closed position to the open position, the valve shaft 201 and the valve plate 202 move in a downstream direction toward the nozzle outlet 206, so that the fuel gas nozzle 204 moves when the valve plate is in 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 captured in the volume 210 of the fuel gas nozzle. Some of this residual volume will flow/diffuse into the scavenge space below the piston 103, where it will mix with the scavenge 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, causing gas slip.

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 has a valve shaft 301 extending along the valve axis 307, a valve plate 302, a valve seat 303, and a fuel gas nozzle ( 304). The valve shaft 301 and 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 possible to move along the valve axis 307 between positions. The valve shaft 301 and valve plate 302 are shown in a closed position in Figure 3A and in an open position in Figure 3B. The valve plate 302 has a first side and a second side, with the valve shaft 301 extending from the first side and the second side facing the fuel gas nozzle 304. The valve shaft 301 and valve plate 302 are moveable between closed and open positions 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 the valve shaft 301 and valve plate 302 no longer need to accommodate the valve plate 302 when in the open position, i.e. the fuel gas nozzle 304 may be designed to not have the volume 210 shown in FIGS. 2A and 2B. Accordingly, the residual volume of fuel gas remaining in the fuel gas nozzle when the valve 300 is closed may 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 comprised of a single piece, where the fuel gas nozzle 304 is formed in the valve housing 308.

Figure 4 schematically shows a cross section of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to one embodiment of the present invention. This fuel gas valve corresponds to the fuel gas valve shown in FIGS. 3A and 3B, the valve housing includes a first part 309 and a second part 310, 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. .

Figure 5 schematically shows a cross section of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to one embodiment of the present invention. This fuel gas valve corresponds to the fuel gas valve shown in Figure 4, which further comprises 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 in that As a result, the residual volume of fuel gas trapped in the fuel gas nozzle 304 can be much lower, and the gas slip can be correspondingly lowered.

FIG. 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 according to one embodiment of the present invention. The valve assembly 690 includes a fuel gas valve 600 and a safety valve 650, where the safety valve 650 has a valve housing 655 with an inlet 656 and an outlet 657, and the fuel gas valve 650 has a valve housing 655 with an inlet 656 and an outlet 657. 600 has a valve housing 605 with an inlet 607 and an outlet (not shown) formed in a valve nozzle 670. Safety valve 650 includes a valve shaft 651, valve plate 652, and valve seat 653. The valve shaft 651 and valve plate 652 have a closed position preventing fuel gas from flowing through safety valve 650 and an open position allowing fuel gas to flow through safety valve 650. It is possible to move between. Valve shaft 651 and valve plate 652 are shown in the closed position in FIG. 6 . 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 to prevent fuel gas from flowing through the fuel gas valve 600 and an open position to allow fuel gas to flow through the fuel gas valve 600. It is possible to move between locations. The valve shaft 601 and valve plate 602 are shown in the closed position in FIG. 6 . The valve housing 655 of the safety valve is directly connected to the valve housing of the first fuel gas valve 605, so that 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 the volume between the safety valve 650 and the fuel gas valve 600.

Additionally, valve assembly 690 may include a position sensor, such as an inductive sensor, that monitors the position of valve shaft 601. The advantage of using a pressure sensor over an inductive position sensor is that the pressure sensor can check the tightness of the entire valve assembly as well as the spindle position. Furthermore, a single pressure sensor can simultaneously monitor the functioning of both the fuel gas valve and the safety valve. Using position sensors requires two separate sensors to monitor two valves. The valve housing 605 of the fuel gas valve includes a first part 609 and a second part 610, and the fuel gas nozzle and valve seat 603 are formed in the second part of the valve housing 610, The first part of the valve housing 609 and the second part of the valve housing 610 are connected upstream of the valve seat 603. The fuel gas valve 600 is configured so that the valve shaft 601 and 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 (toward the inlet 607 of the fuel gas valve 600) when the valve shaft 651 and valve plate 652 move from the closed position to the open position. As a result, if the pressure inside the cylinder increases beyond the closing pressure of the fuel gas valve 600, the fuel gas valve 600 will be forced to open because it is designed in an inverted lift direction. However, by using the safety valve 650 in the normal lift direction, the safety valve's valve plate 652 will be pressed harder against the valve seat 653 in such a situation. It can be guaranteed that it will not be opened by force.

Although some embodiments have been described and shown in detail, the invention is not limited thereto and may be implemented in other ways within the scope of the subject matter defined in the claims below. In particular, it should be understood that alternative embodiments may be utilized and structural and functional changes may be made without departing from the scope of the 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 stated feature, integer, step, or element, but is not limited to one or more other features, integers, steps, or elements. It should be emphasized that it does not exclude the presence or addition of elements or groups thereof.

Claims (10)

A two-stroke uniflow scavenging crosshead internal combustion comprising at least one cylinder (101), a cylinder cover (113), a piston (103), a fuel gas supply system connectable to a fuel gas tank, and a scavenging air system (111). As engine 100,
The cylinder 101 has a cylinder wall, the cylinder cover 113 is arranged at the top of the cylinder 101 and has an exhaust valve 104, and the piston 103 is centered between bottom dead center and top dead center. It is movably arranged within the cylinder 101 along the axis 114, and the scavenging air system 111 has a scavenging air inlet 102 arranged at the lower part of the cylinder 101, and the fuel gas supply system is, for the cylinder 101, arranged at least partially on the cylinder wall and configured to introduce fuel gas into the cylinder 101 through a fuel gas nozzle 304 during the compression stroke, so that the fuel gas flows into the scavenge air. a fuel gas valve (105; 300) capable of mixing with scavenge air from the inlet (102) and allowing the mixture of scavenge air and fuel gas to be compressed prior to ignition;
The fuel gas valve 105 (300) includes a valve shaft 301, a valve plate 302, and a valve seat 303 extending along the valve axis 307, and the valve shaft 301 and the valve The plate (302) is movable along the valve axis (307) between an open and closed position,
The fuel gas valve (105; 300) is arranged at least partially on the cylinder wall at a level below the piston (103) when the piston (103) is at top dead center,
When the fuel gas valve (105; 300) moves from the open position to the closed position, the valve shaft (301) and the valve plate (302) move in the downstream direction, and when the fuel gas valve (105; 300) moves from the closed position to the open position, the valve shaft (301) moves in the downstream direction. 301) and the valve plate 302 are configured to move in the upstream direction,
the fuel gas valve is configured to prevent fuel gas from flowing past the valve plate when the valve shaft and the valve plate move downstream to the closed position,
The internal combustion engine further includes a pilot fuel system configured to inject pilot fuel when the piston approaches top dead center,
The fuel gas nozzle 304 extends along the nozzle axis and has an inlet for receiving fuel gas and an outlet 306 for delivering fuel gas into the interior of the cylinder 101, and can be moved from a closed position to an open position. When the valve shaft 301 and the valve plate 302 move a distance having a first length along the valve axis 307, the fuel gas nozzle 304 moves from the inlet along the nozzle axis. The residual volume of fuel gas trapped in the fuel gas nozzle has a cross-sectional area smaller than the cross-sectional area of the valve plate 302 at a distance of the first length to the outlet side, thereby allowing the residual volume of fuel gas to escape into the scavenging air below the piston to be small. A two-stroke uniflow scavenging crosshead internal combustion engine characterized in that it is maintained. In claim 1,
The fuel gas nozzle (304) is an integrated part of the fuel gas valve (105; 300) in a two-stroke uniflow scavenging crosshead internal combustion engine. In claim 2,
The fuel gas valve (105; 300) includes a valve housing (308), the valve housing (308) includes a first part (309) and a second part (310), and the fuel gas nozzle (304) and the valve seat 303 is formed in the second part 310 of the valve housing 308, and the first part 309 of the valve housing 308 and the second part of the valve housing 308 ( 310) is a 2-stroke uniflow scavenging crosshead internal combustion engine connected upstream of the valve seat 303. The method of any one of claims 1 to 3,
The fuel gas supply system further includes a safety valve 650 arranged upstream of the fuel gas valve 105; 300; 600, and the fuel gas valve 105; 300; 600 is connected to the safety valve 650. A 2-stroke uniflow scavenging crosshead internal combustion engine capable of fluid connection to the fuel gas tank through. In claim 4,
A first sensor is arranged in the space between the safety valve 650 and the fuel gas valve 105; 300; 600, and the first sensor indicates a failed fuel gas valve 105; 300; A two-stroke uniflow scavenged crosshead internal combustion engine configured to directly or indirectly detect pressure changes in the space between 600) and the safety valve 650. In claim 4,
The safety valve 650 has a valve housing 655 with an inlet 656 and an outlet 657, and the fuel gas valve 105; 300; 600 has a valve housing 308 with an inlet and an outlet. , the valve housing 655 of the safety valve 650 is directly connected to the valve housing 308 of the fuel gas valve 105; 300; 600 so that the outlet 657 of the safety valve 650 is connected to the fuel gas. A two-stroke uniflow scavenged crosshead internal combustion engine connected directly to the inlet (607) of the valve (105; 300; 600). In claim 4,
The safety valve 650 includes a valve shaft 651, a valve plate 652, and a valve seat 653 extending along the valve axis, and the valve shaft 651 and the valve plate 652 are open. It is movable along the valve axis between the closed position and the safety valve 650 is configured so that the valve shaft 651 and the valve plate 652 move in a downstream direction when moving from the closed position to the open position. 2-stroke uniflow scavenging crosshead internal combustion engine. delete In claim 1,
The valve plate 302 has a first side and a second side, the valve shaft 301 extends from the first side and the second side faces the outlet 306 of the fuel gas nozzle 304. , the fuel gas valve (105; 300; 600) is a two-stroke uniflow scavenge further comprising a gas displacement element (311) extending from the second side of the valve plate (302) into the fuel gas nozzle (304). type crosshead internal combustion engine. A fuel gas valve (105; 300; 600) for a 2-stroke uniflow scavenging crosshead internal combustion engine (100) according to claim 1,
The fuel gas valve 105; 300; 600 includes a valve shaft 301, a valve plate 302, and a valve seat 303 extending along the valve axis 307, and the valve shaft 301 and The valve plate (302) is movable along the valve axis (307) between an open and closed position,
When the fuel gas valve 105; 300; 600 moves from the open position to the closed position, the valve shaft 301 and the valve plate 302 move in the downstream direction, and when the fuel gas valve 105; 300; 600 moves from the closed position to the open position, the valve The shaft 301 and the valve plate 302 are configured to move in an upstream direction,
The fuel gas valve is configured to prevent fuel gas from flowing past the valve plate when the valve shaft and the valve plate move downstream to the closed position. valve.