JP2022091731A - Internal combustion engine - Google Patents

Abstract

To reduce gas slip in a low pressure two-stroke uniflow scavenged internal combustion engine.SOLUTION: There is disclosed a two-stroke uniflow scavenged 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 scavenge air system, the cylinder having a cylinder wall, the cylinder cover being arranged on top of the cylinder and having an exhaust valve. The fuel gas supply system comprising for the cylinder, a fuel gas valve arranged at least partly in the cylinder wall. The fuel gas valve comprising 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 so that the valve shaft and the valve plate move in an upstream direction when moving from the closed position to the open position.SELECTED DRAWING: Figure 1

Description

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

Two-stroke internal combustion engines are used as propulsion engines in vessels such as container ships, bulk carriers, and tankers. Reducing unwanted exhaust fumes from internal combustion engines is becoming increasingly important.

An effective way to reduce the amount of unwanted exhaust gas is to switch from fuel oil, for example heavy oil (HFO), to fuel gas. The fuel gas can be injected into the cylinder at the end of the compression stroke, where the fuel gas is ignited immediately by either the high temperature reached when the gas in the cylinder is compressed or the ignition of the pilot fuel. obtain. However, in order to inject the fuel gas into the cylinder at the end of the compression stroke, a high pressure gas compressor for compressing the fuel gas before injection is required in order to overcome the high pressure in the cylinder.

However, high pressure gas compressors are expensive and complex to manufacture and maintain. One way to avoid the need for a high pressure compressor is to have a fuel gas valve configured to inject fuel gas at the beginning of a compression stroke where the pressure in the cylinder is fairly low.

EP3015679 discloses such a fuel gas valve. The fuel gas valve comprises a valve shaft, a valve plate, and a valve seat, the valve shaft and the valve plate are movable between the open position and the closed position, and the valve plate is attached to the fuel gas valve in the open position. Extends into the connected gas fuel nozzle.

However, the low pressure 2-stroke uniflow scavenging internal combustion engine has a problem of gas slip. This is a problem because the commonly used fuel gas is a powerful greenhouse gas. As an example, methane can be 84 times more potent than CO2 as a greenhouse gas. Therefore, even a small gas slip causes significant environmental impact over the life of the engine, especially if the gas slip occurs repeatedly every engine cycle. By controlling the timing of the exhaust valve and the fuel gas valve, the amount of gas slip can be limited, but only to a certain extent.

Therefore, there still remains a problem of further reducing gas slip.

According to the first aspect, the present invention is a two-stroke uniflow scavenging crosshead type comprising at least one cylinder, a cylinder cover, a piston, a fuel gas supply system connectable to a fuel gas tank, and a scavenging system. With respect to the internal combustion engine, the cylinder has a cylinder wall, the cylinder cover is located on top of the cylinder and has an exhaust valve, and the piston is along the central axis between the bottom dead point and the top dead point. Movably located in the cylinder, the scavenging system has a scavenging inlet located at the bottom of the cylinder, and the fuel gas supply system is at least partially located in the cylinder wall for the cylinder. Also, it is equipped with a fuel gas valve configured to allow fuel gas to flow into the cylinder through the fuel gas nozzle during the compression stroke, allowing the fuel gas to mix with the scavenging air from the scavenging inlet and with scavenging. Allows the air-fuel mixture to be compressed prior to ignition, the fuel gas valve comprises a valve shaft, valve plate, and valve seat extending along the valve shaft, the valve shaft and valve plate. Movable along the valve axis between the open and closed positions, the fuel gas valve is configured to move upstream as the valve shaft and valve plate move from the closed position to the open position. There is.

After the fuel gas valve is closed and the piston passes through the fuel gas nozzle, the residual fuel gas is captured by the fuel gas nozzle. A part of this residual amount flows in / diffuses into the scavenging space below the piston, where it mixes with the scavenging air. In the next engine cycle, as the piston moves below the scavenging inlet, the air-fuel mixture will flow into the cylinder and some of the air-fuel mixture will exit the exhaust valve directly at the start of the scavenging process, causing gas slip. ..

Therefore, by reversing the lift direction of the fuel gas valve, it is not necessary for the fuel gas nozzle to accommodate the valve plate when the valve shaft and the valve plate are in the open position, so that the internal volume of the fuel gas nozzle can be reduced. .. Therefore, the residual amount of fuel gas remaining in the fuel gas nozzle when the valve is closed can also be reduced, and as a result, the amount of gas slip is reduced. As the gas slip decreases, the efficiency will increase correspondingly.

The internal combustion engine is preferably a uniflow scavenging two-stroke crosshead internal combustion engine with a large low speed turbocharger for propelling a vessel with a power of at least 400 kW per cylinder. The internal combustion engine may include a turbocharger driven by the exhaust gas generated by the internal combustion engine and configured to compress the scavenging. The internal combustion engine can be a dual fuel engine having an Otto cycle mode when powered by fuel gas and a diesel cycle mode when powered by alternative fuels such as heavy oil or marine diesel oil. Such a dual fuel engine has its own dedicated fuel supply system for injecting alternative fuels, which is also an Otto cycle mode for igniting a mixture of fuel gas and scavenging. Can be used for pilot fuel injection when operating in.

The internal combustion engine is capable of injecting a small amount of pilot fuel, for example heavy oil or marine diesel oil, which has been accurately weighed so that just the right amount can ignite the mixture of fuel gas and scavenging. It may be equipped with a dedicated ignition system such as a pilot fuel system, whereby the required amount of pilot fuel is used. Such pilot fuel systems are even smaller in size and exactly the amount compared to dedicated fuel supply systems for alternative fuels that are not suitable for this purpose due to the larger size of the components. Suitable for injecting pilot fuel.

Pilot fuel can be injected into a pre-combustion chamber that is fluidly connected to the combustion chamber of an internal combustion engine. Alternatively, the mixture of fuel gas and scavenging may be ignited by a means equipped with a spark plug or laser ignition. Each cylinder may be provided with one or more scavenging inlets at the bottom of the cylinder and an exhaust outlet at the top of the cylinder.

The valve shaft and valve plate may move upstream by moving away from the center of the cylinder along the valve axis as they move from the closed position to the open position. Correspondingly, the valve shaft and valve plate may move downstream as they move from the open position to the closed position by moving towards the center of the cylinder along the valve axis. The valve shaft may correspond radially so that the valve shaft and valve plate can move straight away from the center of the cylinder as they move from the closed position to the open position. However, the valve shaft may be angled with respect to the radial direction.

The valve plate may have a first side surface and a second side surface, the second side surface is opposite to the first side surface, the valve shaft extends from the first side surface, and the second side surface is used. Part of the side surface is in contact with the valve seat when the valve is in the closed position.

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

Examples of fuel gases 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.

As a result, by incorporating 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 comprises a valve housing, the valve housing comprises a first portion and a second portion, and the fuel gas nozzle and valve seat are formed in a second portion of the valve housing. The first part of the valve housing 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 portions of the valve housing. This is because a gas leak from the connection portion causes a pressure drop upstream of the fuel gas valve when the fuel gas valve is closed, which can be detected by the sensor described below.

In some embodiments, the fuel gas supply system further comprises a safety valve located upstream of the fuel gas valve, which is fluid 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, thereby allowing the fuel gas to close. Create a limited time period during which it is possible to flow through the fuel gas valve.

In some embodiments, a first sensor is placed in the volume between the safety valve and the fuel gas valve, the first sensor being the safety valve and the fuel gas valve indicating the malfunctioning fuel gas valve. It is configured to directly or indirectly detect pressure changes in volume between.

As a result, it is possible to reliably detect malfunctions of different types of fuel gas valves.

The first sensor may be a pressure sensor configured to directly detect a pressure change. Alternatively, the first sensor may be another sensor configured to indirectly detect pressure changes, such as a temperature sensor. A second sensor may be further located in the volume 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 the second sensor). The control unit monitors the sensor signal received from the first sensor and indicates, for example, either a damaged valve plate or valve seat, or a stuck valve shaft, the volume between the safety valve and the fuel gas valve. It may be configured to issue an alarm when a malfunctioning fuel gas valve is detected, such as when a pressure drop is detected. The control unit may be configured to take action in response to an alarm, for example, the control unit ensures that the safety valve of the malfunctioning fuel gas valve is permanently closed and / or. The engine can be controlled to initiate a blow operation to eject gas from the fuel gas supply system and / or to switch from gas mode to an alternative mode, such as diesel mode.

In some embodiments, the safety valve has a valve housing with an inlet and an outlet, the fuel gas valve has a valve housing with an inlet and an outlet, wherein the valve housing of the safety valve is of the safety valve. It is directly connected to the valve housing of the fuel gas valve so that the outlet is directly connected to the inlet of the fuel gas valve.

As a result, the volume of gas between the safety valve and the fuel gas valve can be reduced. This makes it possible to reduce the amount of fuel gas that may be uncontrolledly released into the cylinder if the fuel gas valve is malfunctioning. Since the amount of fuel gas trapped between the fuel gas valve and the safety valve is small, the resulting pressure drop is large, and it may be easier to detect the leaking fuel gas valve.

In some embodiments, the safety valve comprises a valve shaft, valve plate, and valve seat extending along the valve shaft, the valve shaft and valve plate along the valve shaft between the open and closed positions. The safety valve is configured to move downstream as the valve shaft and valve plate move 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 an inverted lift direction and will be forced to open. However, by using a safety valve with a normal lift direction, it can also be ensured that the safety valve does not force open, which means that the valve plate of the safety valve is more resistant to its seat in this situation. This is because it is strongly pressed.

The valve plate of the safety valve may have a first side surface and a second side surface, the second side surface is opposite to the first side surface, the valve shaft extends from the first side surface, and the first Part of the side surface of 2 is in contact with the valve seat when the safety valve is in the closed position.

In some embodiments, the fuel gas nozzle extends along the nozzle shaft and has an inlet for receiving the fuel gas and an outlet for delivering the fuel gas into the cylinder, the valve shaft and the valve shaft. The valve plate moves a distance d1 along the valve axis when moving from the closed position to the open position, and the fuel gas nozzle is smaller than the cross-sectional area of the valve plate with a distance d1 from the inlet along the nozzle axis. Has a cross-sectional area.

As a result, the residual amount of fuel gas captured by the fuel gas nozzle can be reduced, thereby correspondingly reducing gas slip.

In some embodiments, the valve plate has a first side surface and a second side surface, the valve shaft extends from the first side surface, and the second side surface faces the outlet of the fuel gas nozzle. The fuel gas valve further comprises a gas displacement element extending from the second side surface of the valve plate into the fuel gas nozzle.

As a result, the residual amount of fuel gas captured by the fuel gas nozzle can be further reduced, thereby correspondingly reducing gas slip.

The gas replacement element may be tapered towards its end so that the width of the fuel gas nozzle can be narrowed towards its outlet.

According to the second aspect, the present invention relates to a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine disclosed in connection with the first aspect, wherein the fuel gas valve is along the valve shaft. It is provided with an extending valve shaft, valve plate, and valve seat, the valve shaft and valve plate can be moved along the valve shaft between the open position and the closed position, and the fuel gas valve is the valve shaft and the valve seat. It is configured to move upstream as the valve plate moves from the closed position to the open position.

Different aspects of the invention can be realized in different ways, including the two-stroke uniflow scavenging crosshead internal combustion engine described above and below and the fuel gas valve, each of which is at least one of the above aspects. Brings one or more of the benefits and benefits described in connection with each, each corresponding to a preferred embodiment described in connection with at least one of the embodiments disclosed above and / or in the dependent claims. Has one or more preferred embodiments. Further, it will be appreciated that the embodiments described in connection with one of the embodiments described herein are equally applicable to the other embodiments.

The above and / or additional objects, features, and advantages of the invention will be further demonstrated with reference to the accompanying drawings by the following exemplary and non-limiting detailed description of embodiments of the invention.

A cross-sectional view of a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention is schematically shown. A schematic cross-sectional view of a prior art fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine is shown. A cross-sectional view of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention is schematically shown. A cross-sectional view of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention is schematically shown. A cross-sectional view of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention is schematically shown. FIG. 6 shows a schematic view 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 figures illustrating how the invention can be practiced.

FIG. 1 schematically shows a cross-sectional view of a two-stroke uniflow scavenging crosshead internal combustion engine 100 for propelling a marine vessel according to an embodiment of the present invention. The two-stroke internal combustion engine 100 includes a scavenging system 111, an exhaust gas receiver 108, and a turbocharger 109. The two-stroke internal combustion engine has a plurality of cylinders 101 (only a single cylinder is shown in the cross section). Each cylinder 101 has a scavenging inlet 102 arranged at the bottom of the cylinder, a piston 103, a cylinder cover 113 arranged at the top of the cylinder, an exhaust valve 104 arranged at the cylinder cover 113, and 1 for supplying scavenging air. It comprises one or more fuel gas valves 105 (exemplified only schematically). The scavenging inlet 102 is fluidly connected to the scavenging system. The piston 103 is shown at its lowest position (bottom dead center). The piston 103 has a piston rod connected to a crankshaft (not shown). The piston 103 is movably arranged in the cylinder along the central axis 114 between the bottom dead center and the top dead center. The fuel gas valve 105 is shown only schematically. The fuel gas valve 105, at least in part, is located on the cylinder wall between the cylinder cover 113 and the scavenging inlet 102 to form part of the fuel gas supply system and allow fuel gas to flow into the cylinder during the compression stroke. It is configured so that the fuel gas can be mixed with the scavenging air from the scavenging inlet 102 and the mixture of the scavenging air and the fuel gas can be compressed before being ignited. The valve 105 has a fuel gas nozzle, the fuel gas nozzle having one or more nozzle outlets for supplying fuel gas to the inside of the cylinder. The fuel gas supply system can be fluid 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 fluid connectable to the fuel gas tank via the safety valve. The safety valve may be configured to open before a short time period configured to open the fuel gas valve 105 and close after a short time period after the fuel gas valve 105 is configured to close, thereby the main fuel gas. It creates a limited time period during which fuel gas from the supply pipe can flow through the safety valve to the fuel gas valve 105. This means that the safety valve during normal operation operates as much as the fuel gas valve because the safety valve opens immediately before and immediately after the open period of the gas valve 105 in which gas flows into the cylinder. ..

The internal combustion engine 100 includes a dedicated ignition system for igniting a mixture of fuel gas and scavenging at the end of the compression stroke. As an example, a dedicated ignition system uses a small amount of pilot fuel, such as heavy oil or marine diesel oil, that has been accurately weighed so that just the right amount can ignite the mixture of fuel gas and scavenging. It can be a pilot fuel system that can be injected, thereby using only the required amount of pilot fuel. Such pilot fuel systems are even smaller in size and exactly the amount compared to dedicated fuel supply systems for alternative fuels that are not suitable for this purpose due to the larger size of the components. Suitable for injecting pilot fuel. Pilot fuel can be injected into a pre-combustion chamber that is fluidly connected to the combustion chamber of an internal combustion engine. Alternatively, the pilot fuel may be injected into a pre-combustion chamber set fluidly connected to the combustion chamber of the internal combustion engine.

The fuel gas valve 105 enters the cylinder 101 at the start of the compression stroke within 0 to 130 degrees from bottom dead center, that is, when the crankshaft rotates 0 to 130 degrees from the direction at bottom dead center. It can be configured to inject fuel gas. Preferably, the fuel gas valve 105 rotates the crankshaft shaft several degrees from bottom dead center and the piston passes through the scavenging inlet 102 in order to prevent the fuel gas from flowing out of the exhaust valve 104 and the scavenging inlet 102. Later, it is configured to start injecting fuel gas. The scavenging system 111 includes a scavenging receiver 110 and an air cooler 106. The exhaust valve is centrally located in the cylinder cover and the timing of the exhaust valve can be optimized, for example, to close and / or open the exhaust valve to control the compression ratio and / or temperature within the cylinder. Can be variable. The fuel gas valve 105 comprises a valve shaft, a valve plate, and a valve seat extending along the valve shaft, the valve shaft and the valve plate being movable along the valve shaft between the open position and the closed position. be. The fuel gas valve 105 is configured to move upstream when the valve shaft and valve plate move from the closed position to the open position.

2a-2b schematically show a cross-sectional view of the prior art 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 valve plate 202 are movable between a closed position where the fuel gas is prevented from flowing through the fuel gas valve 200 and an open position where the fuel gas is allowed to flow through the fuel gas valve 200. be. The valve shaft 201 and the valve plate 202 are shown in the closed position in FIG. 2a and in the open position in FIG. 2b. The valve shaft 201 and valve plate 202 may be movable between the closed and open positions by an actuator (not shown) controlled by a control unit (not shown). The valve shaft 201 and the valve plate 202 move downstream toward the nozzle outlet 206 as they move from the closed position to the open position, whereby the fuel gas nozzle 204 valves 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 large enough to accommodate the plate. However, after the fuel gas valve is closed and the piston 103 has passed through the fuel gas nozzle 206, a significant residual amount of fuel gas is captured in the volume 210 of the fuel gas nozzle. A part of this residual amount flows in / diffuses into the scavenging space below the piston 103, where it mixes with the scavenging air. In the next engine cycle, as the piston moves below the scavenging inlet, the air-fuel mixture will flow into the cylinder and some of the air-fuel mixture will exit the exhaust valve 104 directly at the start of the scavenging process, causing gas slip. cause.

3a-3b schematically show a cross-sectional view 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 304 having a valve shaft 301 extending along the valve shaft 307, a valve plate 302, a valve seat 303, and a nozzle outlet 306 opening to the cylinder. The valve shaft 301 and the valve plate 302 have a closed position along the valve shaft 307 that prevents fuel gas from flowing through the fuel gas valve 300 and an open position that allows fuel gas to flow through the fuel gas valve 300. It is possible to move between and. The valve shaft 301 and the valve plate 302 are shown in the closed position in FIG. 3a and in the open position in FIG. 3b. The valve plate 302 has a first side surface and a second side surface, the valve shaft 301 extends from the first side surface, and the second side surface faces the fuel gas nozzle 304. The valve shaft 301 and the valve plate 302 may be movable between the 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 when the valve shaft 301 and the valve plate 302 move from the closed position to the open position, they move in the upstream direction away from the nozzle outlet 306. As a result, it is not necessary to accommodate the valve plate 302 when the valve shaft 301 and the valve plate 302 are in the open position, so that the internal volume of the fuel gas nozzle can be reduced, that is, the fuel gas nozzle 304 is shown in FIGS. 2a to 2a. It may be designed without the volume 210 shown in FIG. 2b. Therefore, the residual amount of fuel gas remaining in the fuel gas nozzle when the valve 300 is closed can also be reduced, and as a result, the amount of gas slip is reduced. As the gas slip decreases, the efficiency will increase correspondingly. In this embodiment, the fuel gas valve 300 has a single portion valve housing 308, where the fuel gas nozzle 304 is formed within the valve housing 308.

FIG. 4 schematically shows a cross-sectional view of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention. The fuel gas valve corresponds to the fuel gas valve shown in FIGS. 3a to 3b, but the valve housing includes a first portion 309 and a second portion 310, and the fuel gas nozzle 304 and the valve seat 303 are the first of the valve housing. It is different in that it is formed in the second portion 310 and the first portion 309 of the valve housing and the second portion 310 of the valve housing are connected upstream of the valve seat 303.

FIG. 5 schematically shows a cross-sectional view of a fuel gas valve for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention. The fuel gas valve corresponds to the fuel gas valve shown in FIG. 4, but the fuel gas valve further comprises a gas replacement element 311 extending into the fuel gas nozzle 304 from the second side surface of the valve plate 302. Is different. As a result, the residual amount of fuel gas captured by the fuel gas nozzle 304 can be further reduced, thereby correspondingly reducing gas slip.

FIG. 6 shows a cross-sectional view of a valve assembly 690 of a fuel gas supply system for a two-stroke uniflow scavenging crosshead internal combustion engine according to an embodiment of the present invention. The valve assembly 690 comprises a fuel gas valve 600 and a safety valve 650, the safety valve 650 has a valve housing 655 having an inlet 656 and an outlet 657, and the fuel gas valve 600 has an inlet 607 formed in the valve nozzle 670. It has a valve housing 605 with an outlet (not shown). The safety valve 650 includes a valve shaft 651, a valve plate 652, and a valve seat 653. The valve shaft 651 and valve plate 652 are movable between a closed position where the fuel gas is blocked from flowing through the safety valve 650 and an open position where the fuel gas is allowed to flow through the safety valve 650. The valve shaft 651 and the valve plate 652 are shown in the closed position in FIG. The fuel gas valve 600 includes a valve shaft 601, a valve plate 602, and a valve seat 603. The valve shaft 601 and the valve plate 602 are movable between a closed position where the fuel gas is blocked from flowing through the fuel gas valve 600 and an open position where the fuel gas is allowed to flow through the fuel gas valve 600. be. The valve shaft 601 and the valve plate 602 are shown in the closed position in FIG. The valve housing 655 of the safety valve is directly connected to the valve housing 605 of the fuel gas valve so that the outlet 657 of the safety valve is directly connected to the inlet 607 of the fuel gas valve. The valve assembly 690 further comprises a pressure sensor 608 located in volume between the safety valve 650 and the fuel gas valve 600.

Further, the valve assembly 690 may include a position sensor such as a guidance 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 verify the airtightness of the entire valve assembly as well as the spindle position. In addition, a single pressure sensor can simultaneously monitor the function of both the fuel valve and the safety valve. The position sensor solution requires two separate sensors to monitor the two valves. The valve housing 605 of the fuel gas valve comprises a first portion 609 and a second portion 610, the fuel gas nozzle and the valve seat 603 are formed in the second portion 610 of the valve housing and the first portion of the valve housing. A portion 609 and a second portion 610 of the valve housing are connected upstream of the valve seat 603. The fuel gas valve 600 is configured to move in the upstream direction when the valve shaft 601 and the valve plate 602 move from the closed position to the open position. The safety valve 650 is configured to move downstream (towards the inlet 607 of the fuel gas valve 600) as the valve shaft 651 and valve plate 652 move from the closed position to the open position. As a result, when the pressure inside the cylinder increases beyond the closing pressure of the fuel gas valve 600, the fuel gas valve 600 is designed to have an inverted lift direction and is forced to open. However, by using a safety valve 650 with a normal lift direction, it can also be ensured that the safety valve 650 does not force open, which means that the valve plate 652 of the safety valve is in that situation its valve seat 653. This is because it is pressed more strongly against.

Although some embodiments have been described and illustrated 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 following claims. can. In particular, it should be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the invention.

In a device claim enumerating several means, some of these means can be embodied by the same item of hardware. The fact that a particular measure is described in different dependent claims or described in different embodiments does not indicate that the combination of these measures cannot be used in an advantageous manner.

The term "equipped / equipped", as used herein, is taken to specify the presence of a described feature, integer, step, or component, but one or more other features. It should be emphasized that it does not preclude the existence or addition of integers, steps, components, or groups thereof.

According to the first aspect, the present invention is a two-stroke uniflow scavenging crosshead type comprising at least one cylinder, a cylinder cover, a piston, a fuel gas supply system connectable to a fuel gas tank, and a scavenging system. With respect to the internal combustion engine, the cylinder has a cylinder wall, the cylinder cover is located at the top of the cylinder and has an exhaust valve, and the piston is along the central axis between the bottom dead point and the top dead point. Movably located in the cylinder, the scavenging system has a scavenging inlet located at the bottom of the cylinder, and the fuel gas supply system is at least partially located in the cylinder wall for the cylinder. Also, it is equipped with a fuel gas valve configured to allow fuel gas to flow into the cylinder through the fuel gas nozzle during the compression stroke, allowing the fuel gas to mix with the scavenging air from the scavenging inlet and with scavenging. Allows the air-fuel mixture to be compressed prior to ignition, the fuel gas valve comprises a valve shaft, valve plate, and valve seat extending along the valve shaft, the valve shaft and valve plate. It is movable along the valve axis between the open and closed positions, and when the piston is at the top dead point, the fuel gas valve is at least partially located in the cylinder wall at a height below the piston. The fuel gas valve is configured to move upstream as the valve shaft and valve plate move from the closed position to the open position.

The term "equipped / equipped", as used herein, is taken to specify the presence of a described feature, integer, step, or component, but one or more other features. It should be emphasized that it does not preclude the existence or addition of integers, steps, components, or groups thereof.

The inventions described in the original claims of the present application are described below.
[1] In a two-stroke uniflow scavenging cross-head internal combustion engine including at least one cylinder, a cylinder cover, a piston, a fuel gas supply system connectable to a fuel gas tank, and a scavenging system, the cylinder is a cylinder wall. The cylinder cover is located on top of the cylinder and has an exhaust valve, the piston is located in the cylinder along a central axis between the bottom dead point and the top dead point. Movably located, the scavenging system has a scavenging inlet located at the bottom of the cylinder, and the fuel gas supply system is at least partially located within the cylinder wall for the cylinder. And provided with a fuel gas valve configured to allow fuel gas to flow into the cylinder through the fuel gas nozzle during the compression stroke, allowing the fuel gas to mix with scavenging from the scavenging inlet. Together, it allows the mixture of scavenging air and fuel gas to be compressed prior to ignition, the fuel gas valve comprising a valve shaft, valve plate, and valve seat extending along the valve shaft, said valve. The shaft and the valve plate can move along the valve axis between the open position and the closed position.
When the piston is at top dead center, the fuel gas valve is at least partially located in the cylinder wall at a height below the piston, and the fuel gas valve is located on the valve shaft and the valve shaft. A two-stroke uniflow scavenging crosshead internal combustion engine characterized in that the valve plate is configured to move upstream when moving from the closed position to the open position.
[2] The two-stroke uniflow scavenging type crosshead internal combustion engine according to [1], wherein the fuel gas nozzle is an integral part of the fuel gas valve.
[3] The fuel gas valve comprises a valve housing, the valve housing comprises a first portion and a second portion, and the fuel gas nozzle and the valve seat are formed in the second portion of the valve housing. The two-stroke uniflow scavenging crosshead internal combustion engine according to [2], wherein the first portion of the valve housing and the second portion of the valve housing are connected upstream of the valve seat. institution.
[4] The fuel gas supply system further includes a safety valve arranged upstream of the fuel gas valve, and the fuel gas valve can be fluidly connected to the fuel gas tank via the safety valve, [1] to The 2-stroke uniflow scavenging cross-head internal combustion engine according to any one of [3].
[5] The safety valve and the fuel gas valve have a first sensor arranged in a volume between the safety valve and the fuel gas valve, and the first sensor indicates a fuel gas valve causing a malfunction. The two-stroke uniflow scavenging crosshead internal combustion engine according to [4], which is configured to directly or indirectly detect a pressure change in the volume between and.
[6] 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, and the valve housing of the safety valve has the outlet of the safety valve. The two-stroke uniflow scavenging crosshead internal combustion engine according to [4] or [5], which is directly connected to the valve housing of the fuel gas valve so as to be directly connected to the inlet of the fuel gas valve. institution.
[7] The safety valve includes a valve shaft, a valve plate, and a valve seat extending along the valve shaft, and the valve shaft and the valve plate are along the valve shaft between an open position and a closed position. [4] to [6], wherein the safety valve is configured to move in the downstream direction when the valve shaft and the valve plate move from the closed position to the open position. The 2-stroke uniflow scavenging crosshead internal combustion engine according to any one of the items.
[8] The fuel gas nozzle extends along the nozzle shaft and has an inlet for receiving the fuel gas and an outlet for delivering the fuel gas to the inside of the cylinder, and has the valve shaft and the valve shaft and the outlet. When the valve plate moves from the closed position to the open position, the valve plate moves a distance d1 along the valve shaft, and the fuel gas nozzle keeps a distance d1 from the inlet along the nozzle shaft. The two-stroke uniflow scavenging cross-head type internal combustion engine according to any one of [1] to [7], which has a cross-sectional area smaller than the cross-sectional area of the valve plate.
[9] The valve plate has a first side surface and a second side surface, the valve shaft extends from the first side surface, and the second side surface faces the outlet of the fuel gas nozzle. The two stroke according to any one of [1] to [8], wherein the fuel gas valve further includes a gas replacement element extending from the second side surface of the valve plate into the fuel gas nozzle. Uniflow scavenging crosshead internal combustion engine.
[10] In the fuel gas valve for the 2-stroke uniflow scavenging crosshead internal combustion engine according to any one of [1] to [9], the fuel gas valve extends along the valve shaft. The valve shaft, the valve plate, and the valve seat are provided, and the valve shaft and the valve plate can be moved along the valve shaft between the open position and the closed position.
The fuel gas valve is characterized in that the fuel gas valve is configured to move in the upstream direction when the valve shaft and the valve plate move from the closed position to the open position.

Claims (10)

In 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 system, the cylinder has a cylinder wall. , The cylinder cover is located on top of the cylinder and has an exhaust valve so that the piston can move into the cylinder along a central axis between the bottom dead point and the top dead point. Arranged, the scavenging system has a scavenging inlet located at the bottom of the cylinder, and the fuel gas supply system is at least partially located in the cylinder wall for the cylinder and A fuel gas valve configured to allow fuel gas to flow into the cylinder through the fuel gas nozzle during the compression stroke is provided to allow the fuel gas to mix with the scavenging air from the scavenging inlet and to scavenging. The fuel gas valve comprises a valve shaft, a valve plate, and a valve seat extending along the valve shaft, the valve shaft and the said, allowing the mixture of the fuel gas to be compressed before being ignited. The valve plate can move along the valve axis between the open position and the closed position.
When the piston is at top dead center, the fuel gas valve is at least partially located in the cylinder wall at a height below the piston, and the fuel gas valve is located on the valve shaft and the valve shaft. A two-stroke uniflow scavenging crosshead internal combustion engine characterized in that the valve plate is configured to move upstream when moving from the closed position to the open position. The two-stroke uniflow scavenging crosshead internal combustion engine according to claim 1, wherein the fuel gas nozzle is an integral part of the fuel gas valve. The fuel gas valve comprises a valve housing, the valve housing comprises 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. The two-stroke uniflow scavenging crosshead internal combustion engine according to claim 2, wherein the first portion of the valve housing and the second portion of the valve housing are connected upstream of the valve seat. The fuel gas supply system further includes a safety valve arranged upstream of the fuel gas valve, and the fuel gas valve can be fluidly connected to the fuel gas tank via the safety valve, any of claims 1 to 3. The 2-stroke uniflow scavenging cross-head internal combustion engine described in item 1. A first sensor is arranged in the volume between the safety valve and the fuel gas valve, and the first sensor is between the safety valve and the fuel gas valve indicating a fuel gas valve causing a malfunction. The two-stroke uniflow scavenging crosshead internal combustion engine according to claim 4, which is configured to directly or indirectly detect a pressure change in the volume. 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, and the valve housing of the safety valve has the outlet of the safety valve as the fuel. The two-stroke uniflow scavenging crosshead internal combustion engine according to claim 4 or 5, which is directly connected to the valve housing of the fuel gas valve so as to be directly connected to the inlet of the gas valve. The safety valve comprises a valve shaft, a valve plate, and a valve seat extending along the valve shaft, and the valve shaft and the valve plate can move along the valve shaft between an open position and a closed position. The safety valve is configured to move in the downstream direction when the valve shaft and the valve plate move from the closed position to the open position, according to any one of claims 4 to 6. The described 2-stroke uniflow scavenging crosshead internal combustion engine. The fuel gas nozzle extends along the nozzle shaft and has an inlet for receiving the fuel gas and an outlet for delivering the fuel gas to the inside of the cylinder, and has the valve shaft and the valve plate. Moves a distance d1 along the valve shaft when moving from the closed position to the open position, and the fuel gas nozzle opens a distance d1 from the inlet along the nozzle shaft to the valve plate. The two-stroke uniflow scavenging cross-head internal combustion engine according to any one of claims 1 to 7, which has a cross-sectional area smaller than the cross-sectional area. The valve plate has a first side surface and a second side surface, the valve shaft extends from the first side surface, and the second side surface faces the outlet of the fuel gas nozzle. The two-stroke uniflow scavenging crosshead according to any one of claims 1 to 8, further comprising a gas replacement element extending from the second side surface of the valve plate into the fuel gas nozzle. Type internal combustion engine. In the fuel gas valve for the two-stroke uniflow scavenging crosshead internal combustion engine according to any one of claims 1 to 9, the fuel gas valve is a valve shaft and a valve plate extending along a valve shaft. , And the valve seat, the valve shaft and the valve plate are movable along the valve axis between the open position and the closed position.
The fuel gas valve is characterized in that the fuel gas valve is configured to move in the upstream direction when the valve shaft and the valve plate move from the closed position to the open position.

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