KR20190045794A - Engine for Ship - Google Patents

Abstract

The present invention relates to an engine for a ship, including: a cylinder having a combustion chamber for combusting fuel; a piston reciprocating between a top dead point and a bottom dead point in the combustion chamber; a gas fuel spraying unit supplying gas fuel between the top dead point and the bottom dead point of the piston of the combustion chamber; and an inert gas supply unit for supplying inert gas between the top dead point and the bottom dead point of the combustion chamber.

Description

Engine for Ship

The present invention relates to a marine engine for propelling a marine vessel.

Generally, marine engines include various engines such as diesel engine, gas turbine engine and dual fuel engine. In particular, the Dual Fuel Engine has two fuels. For example, it is widely used in ships due to its advantage of being able to use gas and diesel in parallel.

A ship equipped with such a dual fuel engine (hereinafter referred to as a "ship") uses one of a gas mode for generating propulsion driving force using gas as the main fuel and a diesel mode for generating propulsion driving force using diesel as the main fuel .

The dual fuel engine includes a cylinder having a combustion chamber, a piston reciprocating vertically in the cylinder, a cylinder cover mounted on the cylinder, a main injector provided on the cylinder cover for injecting diesel fuel in the diesel mode, A pilot injector for injecting a small amount of diesel fuel to ignite the gaseous fuel in the mode, an exhaust valve installed in the cylinder cover for discharging the exhaust gas burned in the combustion chamber, an exhaust receiver for receiving the exhaust gas discharged from the combustion chamber, And a gas supply unit installed between the upper and lower sides of the cylinder to supply the gaseous fuel to the combustion chamber.

On the other hand, in the conventional vessel, the inert gas (for example, carbon dioxide, exhaust gas, etc.) is mixed with the scavenging gas supplied from the lower side of the cylinder during the gas mode operation and supplied to the combustion chamber to lower the combustion temperature of the gaseous fuel, . The method of mixing the inert gas with the scavenging can be performed by supplying the inert gas to the scavenging receiver storing the scavenging gas.

However, the marine engine according to the prior art has the following problems.

First, the marine engine according to the prior art has adopted a method of supplying inert gas to the combustion chamber through a scavenging receiver. Scavenge in a two-stroke cycle engine takes the process of exhausting the combustion gas and the process of inhaling new air almost simultaneously. During this process, a part of the scavenge mixed with the inert gas pushes out the residual exhaust gas remaining in the combustion chamber , The exhaust gas is discharged to the outside of the combustion chamber through the exhaust valve to cool the heat load in the combustion chamber, and loss of the inert gas supplied to the combustion chamber occurs.

For this reason, the volume efficiency inside the combustion chamber may be reduced, and unnecessary power loss of the inert gas supply device is generated.

When the loss of the inert gas occurs, the amount of the inert gas mixed in the gaseous fuel is reduced to cause knocking.

Secondly, since the marine engine according to the prior art has a larger capacity of the inert gas supply portion in order to supply a larger amount of inert gas to the scavenging receiver to prevent the loss of the inert gas, a larger installation space There is a problem that the cost of construction due to the increase in capacity is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a marine engine capable of improving the efficiency of the engine by preventing the loss of the inert gas mixed with the gaseous fuel.

In order to solve the above-described problems, the present invention can include the following configuration.

The marine engine according to the present invention comprises: a cylinder having a combustion chamber for burning fuel; A piston reciprocating between a top dead center and a bottom dead center in the combustion chamber; A gas fuel injector for supplying gaseous fuel between a top dead center and a bottom dead center of the piston of the combustion chamber; And an inert gas supply unit for supplying an inert gas between a top dead center and a bottom dead center of the piston of the combustion chamber.

In the marine engine according to the present invention, the gas fuel injector may supply the inert gas from the inert gas supply unit when the gas fuel is supplied to the combustion chamber in the middle of the piston moving from the bottom dead center to the top dead center.

The marine engine according to the present invention may include a measurement unit for measuring the pressure of the combustion chamber. The gas fuel injector may reduce the amount of the inert gas supplied to the gaseous fuel when the measured combustion chamber pressure is less than a preset reference combustion chamber pressure.

The marine engine according to the present invention includes: a first pipeline connecting the inert gas supply unit and the gas fuel injection; A first valve installed in the first pipeline for regulating an amount of inert gas supplied from the inert gas supply unit to the gas fuel injecting unit; And a gaseous fuel supply unit for supplying gaseous fuel to the gaseous fuel injection unit. The gas fuel supply unit includes gas supply means for supplying the gaseous fuel to the gaseous fuel injection unit; A second pipeline connecting the gas supply means and the gas fuel injection unit; And a second valve installed in the second pipeline for regulating the amount of gaseous fuel supplied from the gas supply means to the gaseous fuel injection portion.

The marine engine according to the present invention may include a controller for controlling the first valve and the second valve. The control unit may control the first valve and the second valve such that the inert gas supplied from the inert gas supply unit to the combustion chamber is stopped later than the gas fuel supplied from the gas supply unit to the combustion chamber.

The marine engine according to the present invention may include a controller for controlling the first valve and the second valve. The control unit may control the first valve and the second valve such that the inert gas supplied from the inert gas supply unit to the combustion chamber is supplied at least to the gas fuel supplied from the gas supply unit to the combustion chamber.

The marine engine according to the present invention includes: a control unit for controlling the first valve and the second valve; A measuring unit connected to the control unit and measuring the pressure of the combustion chamber; And a compression unit installed in the first pipeline so as to be positioned between the inert gas supply unit and the first valve and for increasing the pressure of the inert gas supplied from the inert gas supply unit. The control unit may operate the compression unit to increase the pressure of the inert gas supplied to the combustion chamber when the pressure of the combustion chamber measured by the measurement unit is equal to or greater than a preset reference combustion chamber pressure.

According to the present invention, the following effects can be obtained.

The present invention is implemented to supply an inert gas to the combustion chamber when supplying the gaseous fuel, thereby preventing the loss of the inert gas and uniformly mixing the gaseous fuel and the inert gas so that knocking can be prevented In addition, since there is no need to increase the capacity of the inert gas supply unit, it is possible to improve the space utilization of the hull and to reduce the construction cost for preventing loss of the inert gas.

1 is a schematic block diagram of a marine engine according to the present invention;
2 is a schematic view for explaining a gas fuel injecting part, an inert gas supplying part and a measuring part in a marine engine according to the present invention
3 is a schematic block diagram for explaining the first valve, the second valve and the control unit in the marine engine according to the present invention.
FIGS. 4 and 5 are schematic operating states for explaining the supply of the inert gas before the gaseous fuel in the marine engine according to the present invention. FIG.
6 and 7 are schematic operating states for explaining the interruption of the supply of the inert gas to the gaseous fuel later in the marine engine according to the present invention
8 is a schematic graph showing the opening and closing timings of the first valve and the second valve in the marine engine according to the present invention.
9 is a schematic drawing for explaining a compression unit in a marine engine according to the present invention;
10 is a schematic view for explaining a case where exhaust gas is used as an inert gas in a marine engine according to the present invention

It should be noted that, in the specification of the present invention, the same reference numerals as in the drawings denote the same elements, but they are numbered as much as possible even if they are shown in different drawings.

Meanwhile, the meaning of the terms described in the present specification should be understood as follows.

The word " first, " " second, " and the like, used to distinguish one element from another, are to be understood to include plural representations unless the context clearly dictates otherwise. The scope of the right should not be limited by these terms.

It should be understood that the terms "comprises" or "having" does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It should be understood that the term " at least one " includes all possible combinations from one or more related items. For example, the meaning of " at least one of the first item, the second item and the third item " means not only the first item, the second item or the third item, but also the second item and the second item among the first item, Means any combination of items that can be presented from more than one.

Hereinafter, a marine engine according to the present invention will be described in detail with reference to the accompanying drawings.

1 to 10, the marine engine 1 according to the present invention reduces the combustion temperature of the fuel by knocking and supplying the fuel to the combustion chamber by supplying the fuel as well as the inert gas to the combustion chamber, And to prevent abnormal combustion such as pre-ignition. The knocking is a phenomenon that sounds like a hammer knocking by abnormal combustion in a cylinder. The early ignition is a phenomenon in which one of the abnormal combustion is ignited before the piston reaches the top dead center.

For this purpose, the marine engine 1 according to the present invention mainly includes a cylinder 2, a piston 3, an inert gas supply portion 4, and a gaseous fuel injection portion 5.

The cylinder (2) has a combustion chamber for burning fuel. The piston (3) reciprocates between top dead center and bottom dead center in the combustion chamber. The gas fuel injecting section 5 supplies gaseous fuel between the top dead center and the bottom dead center of the piston of the combustion chamber. The inert gas supply unit 4 is for supplying an inert gas between the top dead center and the bottom dead center of the piston of the combustion chamber. Accordingly, the marine engine 1 according to the present invention reduces knocking and pre-ignition by lowering the combustion temperature of the fuel compared with the case where only the fuel is supplied to the combustion chamber by supplying not only the fuel but also the inert gas to the combustion chamber. And the like can be prevented from occurring.

Hereinafter, the cylinder 2, the piston 3, the inert gas supply unit 4, and the gas fuel injection unit 5 will be described in detail with reference to the accompanying drawings.

Referring to Figs. 1 to 10, the cylinder 2 is for burning fuel. The cylinder 2 may be formed inside the engine block 100 (shown in Fig. 4). The cylinder (2) has a combustion chamber (21) through which air, fuel and the like can be supplied. The combustion chamber 21 may have a hollow cylindrical shape. A cylinder liner 2a (shown in FIG. 4) may be provided between the combustion chamber 21 and the engine block 100. The piston (3) can be movably installed in the cylinder (2). For example, the piston 3 can reciprocate in the Y-axis direction (shown in FIG. 2) in the up-and-down direction within the combustion chamber 21. The cylinder 2 may be combined with a gas fuel injecting part 5 for supplying fuel and an inert gas supplying part 4 for supplying an inert gas. Therefore, the gas fuel injecting unit 5 and the inert gas supplying unit 4 can supply the gaseous fuel and the inert gas to the cylinder 2, respectively. The inert gas supply unit 4 may be coupled to the gas fuel injector 5 to supply an inert gas to the cylinder 2 through the gas fuel injector 5. Accordingly, the combustion chamber 21 can receive the inert gas from the gaseous fuel and the inert gas supply unit 4 from the gas fuel injecting unit 5. The inert gas may be carbon dioxide (CO ₂ ), but is not limited thereto and may be other gas as long as it can prevent knocking or early ignition. For example, the marine engine 1 according to the present invention may use an exhaust gas that is combusted and discharged in the combustion chamber 21 as an inert gas. In this case, the exhaust gas discharged from the combustion chamber 21 includes a cooling device for lowering the temperature, a desulfurization device for removing sulfur components, a selective reduction catalyst (SCR) for removing nitrogen oxides (NOx) And the exhaust gas purifying unit for removing foreign substances contained in the exhaust gas purifying unit. The inert gas mixed gas fuel IF (shown in FIG. 2) in which the gaseous fuel and the inert gas are mixed is introduced into the cylinder 2 through a small hole (not shown) May be supplied to the combustion chamber 21 after being supplied. The small hole may be formed in a lower part of the cylinder 2 and formed to penetrate through the cylinder 2 and connected to a scavenging receiver 10 (shown in FIG. 10) filled with air. Accordingly, the air filled in the scavenging receiver 10 can be supplied to the combustion chamber 21 through the small holes. The scavenging receiver 10 includes a turbocharger 30 (shown in Fig. 10), which includes a turbine 21 and a compressor 32, is connected to an exhaust gas receiver 20 (shown in Fig. 10) So that the air can be filled. The volume of the combustion chamber (21) can be increased or decreased as the piston (3) reciprocates. For example, the volume of the cylinder 2 can be reduced when the piston 3 moves upward. In this case, the gaseous fuel and the inert gas supplied to the cylinder 2 can be compressed. When the piston 3 moves in the first position P1 (shown in Fig. 2) and reaches the second position P2 (shown in Fig. 2), a diesel injector (not shown) provided on the upper side of the cylinder 2 ) Mixes the compressed fuel by supplying diesel, so that the mixed gas in which the fuel, the inert gas and the air are mixed is combusted and exploded to move the piston 3 in the downward direction. Thereby, a driving force is generated, and exhaust gas can be generated in the combustion chamber 21. [ The first position P1 is the case where the piston 3 is positioned at the bottom dead center. The second position P2 is the case where the piston 3 is located at the top dead center. The volume of the cylinder 2 can be increased when the piston 3 moves downward. When the piston 3 moves toward the bottom dead center, the air filled in the scavenging receiver 10 can be supplied to the combustion chamber 21. Therefore, the exhaust gas generated by the combustion of the fuel in the combustion chamber 21 can be discharged to the outside of the combustion chamber 21 by the air supplied from the scavenging receiver 10. The exhaust gas may be discharged to the outside of the combustion chamber 21 naturally due to the high temperature. The exhaust gas may be discharged along the exhaust pipe coupled to the cylinder 2 and supplied to the exhaust receiver 20.

 The piston 3 is for compressing the air, fuel and inert gas supplied to the combustion chamber 21. The piston (3) is movably installed in the combustion chamber (21). The piston (3) can reciprocate in the up and down direction in the combustion chamber (21). The piston 3 may be formed in a cylindrical shape, but may be formed in another shape as long as the fuel and air can be compressed while moving in the combustion chamber 21. The piston 3 can move upward by a crankshaft (not shown) that transmits a driving force. The piston (3) can be connected to the crankshaft via a rod-shaped piston rod and a connecting rod. The piston 3 can compress the fuel, the inert gas and the air when the piston 3 moves upward by the crankshaft. The piston 3 can move downward as the fuel, inert gas and air supplied to the cylinder 2 at the top dead center P2 are mixed and combusted and exploded. Therefore, the piston 3 can reciprocate between the bottom dead center P1 and the top dead center P2 within the cylinder 2. [ The bottom dead center point P1 is a point at which the piston 3 is located at the lowest position in the cylinder 2 with respect to the Y-axis direction. The top dead center point P2 is a point at which the piston 3 is located at the highest position inside the cylinder 2 with respect to the Y-axis direction. The marine engine 1 according to the present invention can detonate the compressed fuel to generate a driving force when the piston 3 reaches the top dead center P2.

The inert gas supply unit 4 is for supplying an inert gas to the combustion chamber 21. The inert gas may be carbon dioxide (CO ₂ ), but it is not limited thereto and may be other gas such as exhaust gas as long as knocking or early ignition can be prevented. The inert gas supply unit 4 may store an inert gas. The inert gas supply unit 4 may be formed in a rectangular parallelepiped shape in which the interior of the inert gas supply unit 4 is hollow. However, the inert gas supply unit 4 may be formed in other shapes such as a cylindrical shape as long as it can store inert gas. The inert gas supply unit 4 may be connected to the gas fuel injection unit 5 through a first pipeline 41. The first pipeline 41 is a hose or pipe for moving a fluid such as an inert gas. Accordingly, the inert gas stored in the inert gas supply unit 4 may be supplied to the gas fuel injecting unit 5 through the first pipeline 41. A first valve 42 may be installed in the first pipeline 41. The first valve 42 is for regulating the amount of the inert gas supplied from the inert gas supply part 4 to the gas fuel injecting part 5. The first valve 42 can regulate the amount of the inert gas supplied from the inert gas supply unit 4 to the gas fuel injector 5 by adjusting the opening of the first pipeline 41. For example, when the first valve 42 opens the first pipeline 41, the inert gas stored in the inert gas supply unit 4 flows along the first pipeline 41 to the gas fuel injecting unit 5). In this case, when the first valve 42 opens the opening of the first pipeline 41 largely, a larger amount of inert gas is supplied to the gas fuel injecting portion 5 Can supply. The inert gas supplied to the gas fuel injecting unit 5 may be supplied to the combustion chamber 21. When the first valve 42 closes the first pipeline 41, the inert gas stored in the inert gas supply unit 4 can not be supplied to the gas fuel injecting unit 5. Accordingly, the marine engine 1 according to the present invention is configured such that the inert gas stored in the inert gas supply unit 4 is supplied to the combustion chamber 21 through the gas fuel injection unit 5 using the first valve 42 The amount of the inert gas supplied to the combustion chamber 21 can be controlled.

The gas fuel injector 5 is for supplying fuel and inert gas to the combustion chamber 21. The gas fuel injecting unit 5 may be coupled to the cylinder 2 so as to be positioned between the top dead center P2 and the bottom dead center P1 of the piston 3. Therefore, the gas fuel injector 5 can supply the fuel and the inert gas to the combustion chamber 21 in the middle of the movement of the piston 3 from the bottom dead center P1 to the top dead center P2. For example, when the gas fuel injector 5 supplies the gaseous fuel to the combustion chamber 21 in the middle of the movement of the piston 3 from the bottom dead center P1 to the top dead center P2, The inert gas can be supplied and supplied together. The gas fuel injecting unit 5 can mix the fuel and the inert gas into the combustion chamber 21 by controlling the first valve 42 and the second valve to be described later. As another example, when the gas fuel injecting section 5 is a fuel injection valve, the gas fuel injecting section 5 opens and closes the valves provided therein to inject the fuel supplied from the inert gas supplying section 4 and the gas The fuel supplied from the fuel supply unit may be mixed and supplied. The gas fuel injecting unit 5 can supply the fuel and the inert gas after air is supplied to the combustion chamber 21 through the small holes. The marine engine (1) according to the present invention is a process in which the piston (3) compresses fuel and air. That is, since the inert gas mixture fuel (IF) in which the fuel and the inert gas are mixed in advance can be supplied to the combustion chamber (21) in the middle of the movement of the piston (3) from the bottom dead center (P1) to the top dead center The combustion temperature of the fuel can be lowered compared with the case where only the fuel is supplied to the combustion chamber 21 in the process. When the combustion temperature is lowered, the explosion pressure for burning the fuel can be increased. Explosion pressure is proportional to the output generated by the engine. Therefore, the marine engine 1 according to the present invention can supply the inert gas mixture gas fuel IF mixed with the fuel and the inert gas to the combustion chamber 21 during the compression process of the piston 3, The efficiency of the engine can be further improved as compared with the case of supplying only the fuel, and knocking and pre-ignition can be prevented. In the marine engine 1 according to the present invention, the inert gas mixture gas fuel IF, in which the fuel and the exhaust gas are mixed in the middle of the piston 3 moving from the bottom dead center P1 to the top dead center P2, The air and the fuel inside the combustion chamber 21 can be uniformly mixed. This is because air and unburned fuel are mixed together in the exhaust gas. Accordingly, the marine engine 1 according to the present invention can improve the combustion efficiency by uniformly mixing the air, fuel, and exhaust gas supplied to the combustion chamber 21, thereby preventing the output for propelling the ship from lowering And it is possible to prevent knocking from occurring and to increase the service life.

Referring to FIG. 2, the marine engine 1 according to the present invention may include a measurement unit 6.

The measuring unit 6 is for measuring the pressure of the combustion chamber 21. The measurement unit 6 may be installed on a cylinder cover provided on the cylinder 2, but it is not limited thereto. The measurement unit 6 may be installed at another position as long as the pressure of the combustion chamber 21 can be measured. The measuring unit 6 may be a pressure sensor. The number of the measuring units 6 may be one, but a plurality of the measuring units 6 may be installed at different positions of the cylinders 2 in order to increase the reliability of the pressure measurement in the combustion chamber 21. The measuring unit 6 may be connected to the gas fuel injecting unit 5 by at least one of wireless communication and wire communication. Therefore, the measuring section 6 can provide the measured pressure of the combustion chamber 21 to the gas fuel injecting section 5. The gaseous fuel injecting unit 5 receives the pressure of the combustion chamber 21 from the measuring unit 6 and compares the measured pressure with a preset reference combustion chamber pressure to determine the amount of the inert gas supplied to the combustion chamber 21 Can be adjusted. The reference combustion chamber pressure refers to a pressure in the combustion chamber in which knocking and early ignition do not occur during fuel combustion, and can be preset by an operator.

For example, the gas fuel injecting section 5 is supplied to the fuel when the combustion chamber pressure measured by the measuring section 6 is equal to or higher than a preset reference combustion chamber pressure. That is, the amount of the inert gas mixed into the fuel can be increased. The gas fuel injector 5 can increase the amount of the inert gas supplied to the combustion chamber 21 by controlling the first valve 42 such that the opening of the first pipeline 41 is increased . In this case, the gas fuel injecting unit 5 may control the second valve to maintain or reduce the amount of fuel supplied to the combustion chamber 21. [ Accordingly, the marine engine 1 according to the present invention increases the amount of the inert gas supplied to the combustion chamber 21 when the combustion chamber pressure measured by the measurement unit 6 is equal to or higher than a preset reference combustion chamber pressure, It is possible to prevent knocking and early ignition from occurring by lowering the combustion temperature of the gaseous fuel. In the marine engine 1 according to the present invention, when the combustion chamber pressure measured by the measuring unit 6 is equal to or higher than a preset reference combustion chamber pressure, the amount of the inert gas supplied to the combustion chamber 21 is increased, 21, the burning rate of the fuel can be lowered, so that the occurrence of knocking can be reduced or prevented.

For example, the gas fuel injecting unit 5 may reduce the amount of the inert gas mixed into the fuel when the combustion chamber pressure measured by the measuring unit 6 is less than a preset reference combustion chamber pressure. The gas fuel injecting unit 5 can reduce the amount of the inert gas supplied to the combustion chamber 21 by controlling the first valve 42 so that the opening of the first pipeline 41 becomes small . In this case, the gas fuel injecting unit 5 may control the second valve to maintain or increase the amount of fuel supplied to the combustion chamber 21. Accordingly, the marine engine 1 according to the present invention reduces the amount of the inert gas supplied to the combustion chamber 21 when the combustion chamber pressure measured by the measurement unit 6 is less than a preset reference combustion chamber pressure, The combustion temperature of the inert gas mixed gas fuel can be increased as compared with the reference combustion chamber pressure or more, so that the output of the engine can be prevented from lowering. The marine engine 1 according to the present invention reduces the amount of inert gas supplied to the combustion chamber 21 when the combustion chamber pressure measured by the measurement unit 6 is less than a preset reference combustion chamber pressure, The combustion speed of the inert gas mixed gas fuel can be advanced as compared with the reference combustion chamber pressure or more, so that the output of the engine can be prevented from being lowered due to abnormal combustion.

In the marine engine 1 according to the present invention, the gas fuel injecting unit 5 may mix the gaseous fuel and the inert gas to supply the mixed gas to the combustion chamber 21, but the present invention is not limited to this. The diesel fuel In the mode operation, the first valve 42 and the second valve may be controlled to supply only the inert gas to the combustion chamber 21. Accordingly, since the marine engine 1 according to the present invention can reduce the combustion temperature of the fuel by supplying the inert gas to the combustion chamber 21 not only in the gas mode but also in the diesel mode operation, knocking and pre-ignition -ignition) can be prevented or reduced.

Referring to Fig. 3, the marine engine 1 according to the present invention may include a gas fuel supply part 7. Fig.

The gaseous fuel supply part 7 is for supplying gaseous fuel to the gaseous fuel injection part 5. The gas fuel supply unit 7 may vaporize the LNG stored in the LNG storage tank and supply it to the gas fuel injection unit 5 when the ship is an LNG line. The gas fuel supply unit 7 may supply a boil off gas (BOG) generated in the LNG storage tank to the gas fuel injection unit 5. The gas fuel supply unit 7 may include gas supply means 71, a second pipeline 72 and a second valve 73.

The gas supply means (71) is for supplying fuel to the gas fuel injecting section (5). Here, the fuel may be a gas. The gas supply means 71 may be connected to the gas fuel injecting unit 5 through the second pipeline 72 at one side. The other side of the gas supply means 71 may be connected to the LNG storage tank through a pipe or a pipe. Therefore, the gas supply means 71 can supply the fuel from the LNG storage tank to the gas fuel injection portion 5. In this case, the fuel may be in a gaseous state. The gas supply means 71 may be a transfer device such as a compressor, an impeller and a pump for generating a transfer force for transferring the fuel. However, the gas supply means 71 is not limited to this, It may be another device. The gas supply means 71 may be a gas fuel storage tank storing the gaseous fuel at a constant pressure. In this case, the gas fuel supply part 7 may not include the transfer device. The gas supply means 71 can supply fuel to the combustion chamber 21 by supplying fuel to the gas fuel injection portion 5. The gas supply means 71 can supply fuel to the combustion chamber 21 in the middle of the movement of the piston 3 from the first position P1 to the second position P2. In this case, the marine engine 1 according to the present invention causes the fuel to escape through the exhaust pipe. That is, the combustion chamber 21 can be closed to prevent methane slip from occurring. The marine engine 1 according to the present invention is configured such that the inert gas mixed gas fuel mixed with the fuel and the inert gas is supplied to the combustion chamber 21 through the gas fuel injecting unit 5, 21) and the exhaust pipe, the combustion chamber 21 can be closed to prevent methane slip. The inert gas supplied from the inert gas supply unit 4 and the gas supply unit 71 are supplied to the combustion chamber 21 by supplying the fuel to the gas fuel injection unit 5 by the gas supply unit 71. [ The mixed gas fuel (IF) can be supplied. In this case, the pressure of the inert gas mixture gas fuel (IF) supplied to the combustion chamber (21) may be between about 3 bar and about 30 bar depending on the engine load, To 22 bars. In this case, the pressure of the inert gas supplied by the inert gas supply unit 4 may be relatively lower than the supply pressure of the gaseous fuel supplied by the gas supply unit 71. This is because, in order to smoothly supply the gaseous fuel to the cylinder (2). If the pressure of the inert gas mixture gas fuel IF exceeds 30 bar, the capacity of the inert gas supply unit 4 and the gas supply unit 71 must be increased to increase the overall size of the engine. If the pressure of the inert gas mixture gas fuel IF is less than 3 bar, the inert gas mixture gas fuel IF is injected into the combustion chamber 21 due to the pressure of air previously supplied to the combustion chamber 21 through the small holes There is a problem that it can not be supplied smoothly.

One end of the second pipeline 72 may be coupled to the gas supply means 71 and the other end thereof may be coupled to the gas fuel injector 5. The second pipeline 72 is for moving the fuel, and may be a flow path such as a pipe or a pipe. The second pipeline 72 may be coupled to the gas fuel injector 5 to communicate with the first pipeline 41. Therefore, the gas fuel injecting unit 5 can mix the fuel supplied through the second pipeline 72 and the inert gas supplied through the first pipeline 41 and supply the mixed gas to the combustion chamber 21 have. The gas fuel injecting unit 5 may be formed such that the fuel supplied from the second pipeline 72 is supplied from the upper side of the inert gas supplied from the first pipeline 41. The upper side may denote a direction opposite to the direction of gravity. Accordingly, the fuel that is moved through the second pipeline 72 may be supplied to the gas fuel injecting section 5 by gravity. Therefore, in the marine engine 1 according to the present invention, since the gas supply means 71 can lower the load for moving the fuel to the gas fuel injection portion 5, the service life of the gas supply means 71 Lt; / RTI > A second valve (73) may be installed in the second pipeline (72).

The second valve (73) is for opening and closing the second pipeline (72). The second valve 73 may be installed in the second pipeline 72 so as to be positioned between the gas supply means 71 and the gas fuel injection unit 5. The second valve 73 may be a gate valve that pushes a valve into the second pipeline 72 and locks the valve. However, the second valve 73 may be a rotary valve such as a ball valve, It may be another valve, such as a globe valve that closes or locks a valve on a pipe. The second valve (73) is connected to the gaseous fuel injection part (5) in at least one of a wired communication and a wireless communication so that it is controlled by the gaseous fuel injection part (5) ) Can be opened or closed. The second valve 73 can adjust the amount of fuel supplied from the gas supply means 71 to the gas fuel injecting portion 5 by adjusting the opening of the second pipeline 72. For example, when the second valve (73) opens the second pipeline (72), the fuel supplied by the gas supply means (71) flows along the second pipeline (72) 5). In this case, when the second valve 73 opens the opening of the second pipeline 72 largely, a larger amount of fuel is supplied to the gas fuel injecting portion 5 than when the opening degree is made small . The fuel supplied to the gas fuel injecting unit 5 may be supplied to the combustion chamber 21. For example, when the second valve (73) closes the second pipeline (71), the fuel supplied by the gas supply means (71) can not be supplied to the gas fuel injecting section (5). The first valve 42 and the second valve 73 are connected to a control unit to be described later by at least one of a wired communication and a wireless communication so that the first valve 42 and the second valve 73 are controlled by the control unit, The second pipeline 72 may be opened or closed. A pressure reducing valve (74) may be provided between the second valve (73) and the gas supply means (71). The pressure reducing valve (74) is for reducing the pressure of the gaseous fuel supplied from the gas supply means (71).

3 and 4, the marine engine 1 according to the present invention may include a control unit 8.

The control unit 8 is for controlling the first valve 42 and the second valve 73. The control unit 8 may control the first valve 42 and the second valve 73 according to the crank angle of the crankshaft connected to the piston 3. The control unit 8 can control the first valve 42 to open or close the first pipeline 41 according to the rotation angle of the crankshaft. The control unit 8 may control the second valve 73 to open or close the second pipeline 72 according to the rotation angle of the crankshaft. The control unit 8 may acquire a rotation angle of the crankshaft through a governor that detects the rotation speed of the crankshaft, but may acquire the rotation angle of the crankshaft through another device. The control unit 8 may be connected to an angle sensor, a governor, or the like through at least one of a wire device and a wireless device, thereby obtaining a rotation angle of the crankshaft.

 The control unit 8 can adjust the opening and closing timings of the first valve 42 and the second valve 73 according to the rotation angle of the crank shaft obtained after obtaining the rotation angle of the crankshaft. For example, the control unit 8 may control the first valve 42 to open and close the first pipeline 41 according to the angle of rotation of the crankshaft. When the first pipeline 41 is opened, the inert gas stored in the inert gas supply unit 4 is supplied to the gas fuel injector 5 along the first pipeline 41, . When the first pipeline 41 is closed, the inert gas supplied from the inert gas supply unit 4 to the combustion chamber 21 along the first pipeline 41 may be shut off. For example, the control unit 8 may control the second valve 73 to open / close the second pipeline 72 according to the angle of rotation of the crankshaft. When the second pipeline 72 is opened, fuel is supplied from the gas supply means 71 to the gas fuel injector 5 along the second pipeline 72 to be supplied to the combustion chamber 21 . When the second pipeline 72 is closed, fuel supply to the gas fuel injector 5 may be interrupted. The inert gas supplied along the first pipeline 41 and the fuel supplied along the second pipeline 72 are mixed in the gas fuel injector 5 before being supplied to the combustion chamber 21, . Therefore, the marine engine 1 according to the present invention is configured to mix the fuel and the inert gas outside the combustion chamber 21 and then supply the mixed inert gas mixture gas IF to the combustion chamber 21, The mixing ratio to be mixed with air supplied in advance can be increased, so that the occurrence of knocking can be remarkably reduced or prevented.

4 to 9, the control unit 8 controls the flow of the inert gas from the inert gas supply unit 4 to the combustion chamber 21 through the first pipeline 41 and the gas fuel injection unit 5, The supplied inert gas is supplied from the gas supply means 71 to the combustion chamber 21 sequentially through the second pipeline 72 and the gas fuel injecting section 5, So that the first valve 42 and the second valve 73 can be controlled. Here, the fuel may be a gas. 9 is a schematic graph showing the opening and closing timings of the exhaust valve, the first valve and the second valve in the marine engine according to the present invention. The horizontal axis represents the crank angle of the crankshaft. The vertical axis represents the valve lift. The first line (L1) is a graph showing the opening and closing timings of the first valve (42). The second line (L2) is a graph showing the opening and closing timing of the second valve (73). The third line L3 is a graph showing the opening and closing timings of the exhaust valve (not shown). In the graph, the exhaust valve, the first valve 42 and the second valve 73 open the combustion chamber 21, the first pipeline 41 and the second pipeline 72, respectively, in the upward direction of the vertical axis. In the graph, the exhaust valve, the first valve 42 and the second valve 73 close the combustion chamber 21, the first pipeline 41, and the second pipeline 72, respectively, in the lower direction of the vertical axis. The control unit 8 periodically opens and closes the combustion chamber, the first pipeline 41 and the second pipeline 72 in accordance with the rotation angle of the crankshaft, and the exhaust valve, the first valve 42 and the second valve 73, The first valve 42 and the second valve 73 can be controlled. Referring to FIG. 9, the first line L1 and the second line L2 are located on the right side of the third line L3. This means that the first valve 42 and the second valve 73 open and close the first pipeline 41 and the second pipeline 72 after the exhaust valve closes the combustion chamber 21. Accordingly, the marine engine 1 according to the present invention can prevent occurrence of methane slip. The second line L2 is located inside the first line L1. This is because the first valve 42 first opens the first pipeline 41 and then the second valve 73 opens the second pipeline 72 and the second valve 73 opens the second pipeline 72 Means that the first valve 42 closes the first pipeline 41 after closing the first pipeline 72.

Referring to FIGS. 4 to 6, when the first valve 42 and the second valve 73 are opened, the control unit 8 determines whether the inert gas is supplied from the inert gas supply unit 4 to the combustion chamber 21 The first valve 42 and the second valve 73 can be controlled so that the inert gas IG is supplied at least from the gas supplied from the gas supply means 71 to the combustion chamber 21. The control unit 8 controls the first valve 42 and the second valve 73 such that the second pipeline 72 is opened after the first pipeline 41 is opened according to the rotation angle of the predetermined crankshaft . Therefore, the inert gas IG supplied from the inert gas supply unit 4 to the combustion chamber 21 can be supplied to the combustion chamber 21 from the gas supply unit 71 before the fuel is supplied to the combustion chamber 21. The marine engine 1 according to the present invention reduces the pressure due to the flow rate of the inert gas by supplying the inert gas IG first than the fuel when the inert gas mixture gas fuel IF is supplied to the combustion chamber 21, Fuel injected into the gas fuel injecting unit 5 can be sucked into the inert gas moving through the gas fuel injecting unit 5. Accordingly, the marine engine 1 according to the present invention can lower the load of the gas supply means 71, thereby extending the service life of the gas supply means 71. [ In the marine engine 1 according to the present invention, the exhaust gas and the fuel (Fuel) are mixed in advance in the gas fuel injecting section 5 and supplied to the combustion chamber 21, (NO), which is an exhaust gas pollutant, can be reduced as compared with the case where only the fuel is supplied, and at the same time, knocking and pre-ignition -ignition) can be improved.

 The control unit 8 may control the first valve 42 and the second valve 73 so that the first pipeline 41 and the second pipeline 72 are simultaneously opened. The control unit 8 can control the first valve 42 and the second valve 73 so that the first pipeline 41 and the second pipeline 72 are simultaneously opened according to the rotation angle of the predetermined crankshaft . In this case, the fuel and the inert gas IG are simultaneously supplied to the gas fuel injecting unit 5, so that the fuel and the inert gas can be simultaneously mixed and supplied to the combustion chamber 21. Therefore, the marine engine 1 according to the present invention is capable of controlling the air supplied to the combustion chamber 21 through the small holes and the inert gas mixture gas IF supplied to the combustion chamber 21 through the gas fuel injection part 5, It is possible to improve the efficiency of the engine by improving the knocking and the pre-ignition compared to the case of supplying only the fuel instead of the inert gas mixture gas fuel IF.

6 and 7, the control unit 8 determines the closing timing of the first valve 42 and the second valve 73 based on the rotation angle of the predetermined crankshaft, It is possible to control the first valve 42 and the second valve 73 so that the first pipeline 41 is closed after it is closed. The inert gas IG supplied to the combustion chamber 21 in the first pipeline 41 can be stopped later than the fuel supplied to the combustion chamber 21 in the second pipeline 72. [ The marine engine 1 according to the present invention stops the supply of the inert gas mixture fuel IF supplied to the combustion chamber 21 first and stops the supply of the inert gas IG later, The fuel remaining in the jetting section 5 can be reduced. Accordingly, the marine engine 1 according to the present invention reduces the amount of fuel remaining in the gas fuel injecting unit 5 and reduces the supply of fuel to the combustion chamber 21, thereby supplying only the fuel to the combustion chamber 21 And the fuel is prevented from sticking due to the fuel remaining in the gas fuel injecting unit 5, so that the use life of the gas fuel injecting unit 5 can be shortened, Can be increased.

9, the marine engine 1 according to the present invention may further include a compression unit 9. [

The compression section 9 is for increasing the pressure of the inert gas supplied from the inert gas supply section 4. Accordingly, the compression section 9 can increase the pressure of the inert gas supplied to the combustion chamber 21. For example, if the pressure of the combustion chamber is higher than the pressure of the inert gas before the gas fuel injecting unit 5 supplies the inert gas mixture gas fuel IF to the combustion chamber 21, There is a problem that the inert gas is not supplied to the combustion chamber 21 and the air supplied to the combustion chamber 21 flows back toward the inert gas supply unit 4. [ Accordingly, the compression unit 9 can supply the inert gas to the combustion chamber 21 with an increased pressure of the inert gas to prevent the above-described problems from occurring. The compression unit 9 may be a compression device such as a compressor, an impeller, or the like, but is not limited thereto and may be a different device as long as the pressure of the inert gas can be increased. The compression unit 9 may be installed in the first pipeline 41 to be positioned between the inert gas supply unit 4 and the first valve 42. In this case, the first pipeline 41 located between the compression section 9 and the first valve 42 can be kept filled with the inert gas whose pressure is increased by the compression section 9 . In this state, when the first valve 42 is opened by the gas fuel injecting unit 5 or the control unit 8, the inert gas in the compressed state can be immediately supplied to the gas fuel injecting unit 5 It is possible to increase the response of the combustion chamber 21 to the inert gas supply. The compression unit 9 is installed between the cylinder 2 and the first valve 42 to increase the pressure of the inert gas supplied to the combustion chamber 21 or to increase the pressure of the inert gas supplied to the inert gas supply unit 4 Thereby increasing the pressure of the inert gas stored in the inert gas supply unit 4. [ Accordingly, the inert gas supply unit 4 may store an inert gas whose pressure has been increased by the compression unit 9. [ Therefore, the marine engine 1 according to the present invention can quickly supply the inert gas from the inert gas supply part 4 to the gas fuel injection part 5.

 The compression unit 9 may be controlled by the control unit 8 by being connected to the control unit 8 by at least one of wireless communication and wired communication. The control unit 9 operates the compression unit 9 so that the pressure of the inert gas supplied to the combustion chamber 21 is increased when the pressure of the combustion chamber measured by the measurement unit 6 is equal to or greater than a preset reference combustion chamber pressure . Accordingly, since the marine engine 1 according to the present invention can supply the inert gas to the combustion chamber 21 at a pressure higher than the pressure of the combustion chamber 21, it is possible to supply the inert gas to the combustion chamber 21 through the small- It is possible to prevent air from flowing back to the inert gas supply unit 4 through the first pipeline 41. [ The control unit 9 may not operate the compression unit 9 if the pressure of the combustion chamber measured by the measurement unit 6 is less than a preset reference combustion chamber pressure. Therefore, the marine engine 1 according to the present invention does not operate the compression section 9 when the pressure of the combustion chamber measured by the measurement section 6 is less than the preset reference combustion chamber pressure, Thereby reducing maintenance and replacement costs.

Referring to FIG. 10, the marine engine 1 according to the present invention can use exhaust gas stored in the exhaust receiver 20 as an inert gas.

The exhaust receiver 20 is for receiving and storing the exhaust gas discharged from the combustion chamber 21. The exhaust receiver 20 may be connected to the cylinder 2 through an exhaust pipe such as a pipe or a pipe. The exhaust pipe is connected to a cylinder cover (not shown) provided on the upper side of the cylinder 2 so that the exhaust pipe can communicate with the combustion chamber 21 or shut off the communication with the opening and closing of the exhaust valve. Accordingly, when the exhaust valve is opened, the combustion chamber 21 and the exhaust pipe communicate with each other, so that the exhaust receiver 20 can receive exhaust gas from the combustion chamber 21. When the exhaust valve is closed, the combustion chamber (21) and the exhaust pipe are blocked, so that the exhaust receiver (20) can not receive exhaust gas from the combustion chamber (21). The exhaust receiver 20 may be formed in a rectangular parallelepiped shape having an empty interior, but is not limited thereto and may be formed in a cylindrical shape or the like if it can store exhaust gas. The exhaust receiver 20 may be connected to the gas fuel injector 5 through a first pipeline 41. The first pipeline 41 is a pipe or pipe for moving a fluid such as an exhaust gas. Accordingly, the exhaust gas stored in the exhaust receiver 20 can be supplied to the gas fuel injecting unit 5 through the first pipeline 41. A first valve 42 may be installed in the first pipeline 41. The first valve 42 is for regulating the amount of exhaust gas supplied from the exhaust receiver 20 to the gas fuel injector 5. The first valve 42 can regulate the amount of exhaust gas supplied from the exhaust receiver 20 to the gas fuel injector 5 by adjusting the opening of the first pipeline 41. For example, when the first valve 42 opens the first pipeline 41, the exhaust gas stored in the exhaust receiver 20 flows along the first pipeline 41 to the gas fuel injector 5 ). ≪ / RTI > In this case, when the first valve 42 opens the opening of the first pipeline 41 largely, a larger amount of exhaust gas is supplied to the gas fuel injecting portion 5 Can supply. The exhaust gas supplied to the gas fuel injecting unit 5 may be supplied to the combustion chamber 21. When the first valve 42 closes the first pipeline 41, the exhaust gas stored in the exhaust receiver 20 can not be supplied to the gaseous fuel injection part 5. Therefore, the marine engine 1 according to the present invention can supply the exhaust gas stored in the exhaust receiver 20 to the combustion chamber 21 through the gas fuel injecting section 5 using the first valve 42 The amount of exhaust gas supplied to the combustion chamber 21 can be controlled. The exhaust receiver 20 may be connected to the turbocharger 30 through a separate pipe. Accordingly, the turbocharger 30 can receive the exhaust gas from the exhaust receiver 20, compress the external air, and supply the compressed air to the scavenging receiver 10. In this case, a cooler 33 for cooling air compressed by the turbocharger 30 is provided between the turbocharger 30 and the scavenging receiver 10, and a cooler 33 for removing moisture from the cooled compressed air. A water mist catcher 34 may be provided. Between the exhaust receiver 20 and the cooler 33, a bypass line for bypassing the turbocharger 30 may be installed in the exhaust receiver 20. The bypass line may be provided with an EGB valve 35 for bypassing or shutting off the exhaust gas. Between the exhaust receiver 20 and the first valve 42, devices for cooling and purifying the exhaust gas may be installed in the first pipeline 41. For example, the EGR valve 36, the free spray 37, the EGR cooler 38, the EGR water mist catcher 39, the EGR blower 40, the pressure regulating valve 43 and the check valve 44 have. The EGB valve 36 is for supplying or blocking the exhaust gas from the exhaust receiver 20 to the gas fuel injector 5. [ The free spray 37 is for removing sulfur components from the exhaust gas. The EGR cooler 38 is for cooling the exhaust gas. The EGR water mist catcher 39 is for removing moisture from the exhaust gas. The EGR blower 40 is for compressing the exhaust gas. The pressure regulating valve 43 regulates the pressure of the exhaust gas supplied to the gas fuel injecting unit 5. The check valve 44 is provided to prevent exhaust gas from flowing back to the exhaust receiver 20 from the combustion chamber 21. The exhaust gas stored in the exhaust receiver 20 through these devices can be supplied to the gas fuel injector 5 by cooling, removing water, adjusting the pressure, and the like. Accordingly, since the marine engine 1 according to the present invention can use the exhaust gas stored in the exhaust receiver 20 as an inert gas, it is possible to prevent the occurrence of knocking or early ignition by recycling exhaust gas exhausted to the outside The service life of the engine can be increased.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of.

1: Marine engine
2: cylinder 3: piston
4: Inert gas supply part 5: Gas fuel injection part
6: measuring part 7: gas fuel supply part
8: control unit 9: compression unit
10: Scavenging receiver 20: Exhaust receiver
30: Turbocharger 31: Turbine
32: compressor 33: cooler
34: Water mist catcher 35: EGB valve
36: EGB valve 37: Free spray
38: EGR cooler 39: EGR water mist catcher
40: EGR blower 41: first pipeline
42: first valve 43: pressure regulating valve
44: Check valve 71: Gas supply means
72: second pipeline 73: second valve
74: Pressure reducing valve

Claims (8)

A cylinder having a combustion chamber for burning fuel;
A piston reciprocating between a top dead center and a bottom dead center in the combustion chamber;
A gas fuel injector for supplying gaseous fuel between a top dead center and a bottom dead center of the piston of the combustion chamber; And
And an inert gas supply unit for supplying an inert gas between a top dead center and a bottom dead center of the piston of the combustion chamber. The method according to claim 1,
Wherein the gas fuel injector supplies inert gas from the inert gas supply unit when the gas fuel is supplied to the combustion chamber in the middle of the movement of the piston from the bottom dead center to the top dead center. The method according to claim 1,
And a measuring section for measuring a pressure of the combustion chamber,
Wherein the gas fuel injector increases the amount of the inert gas supplied to the gaseous fuel when the measured combustion chamber pressure is equal to or greater than a predetermined reference combustion chamber pressure. The method according to claim 1,
And a measuring section for measuring a pressure of the combustion chamber,
Wherein the gas fuel injector reduces the amount of the inert gas supplied to the gaseous fuel when the measured combustion chamber pressure is less than a preset reference combustion chamber pressure. The method according to claim 1,
A first pipeline connecting the inert gas supply unit and the gas fuel injection unit;
A first valve installed in the first pipeline for regulating an amount of inert gas supplied from the inert gas supply unit to the gas fuel injecting unit; And
And a gas fuel supply part for supplying the gaseous fuel to the gas fuel injecting part,
The gas fuel supply unit includes:
Gas supplying means for supplying the gaseous fuel to the gas fuel injecting portion;
A second pipeline connecting the gas supply means and the gas fuel injection unit;
And a second valve installed in the second pipeline for regulating the amount of gaseous fuel supplied from the gas supply means to the gaseous fuel injection portion. 6. The method of claim 5,
And a control unit for controlling the first valve and the second valve,
Wherein the control unit controls the first valve and the second valve such that the inert gas supplied from the inert gas supply unit to the combustion chamber is supplied later than the gaseous fuel supplied from the gas supply unit to the combustion chamber The marine engine. 6. The method of claim 5,
And a control unit for controlling the first valve and the second valve,
Wherein the control unit controls the first valve and the second valve such that the inert gas supplied from the inert gas supply unit to the combustion chamber is supplied at least to the gas fuel supplied from the gas supply unit to the combustion chamber. engine. 6. The method of claim 5,
A control unit for controlling the first valve and the second valve;
A measuring unit connected to the control unit and measuring the pressure of the combustion chamber; And
And a compression unit installed in the first pipeline so as to be positioned between the inert gas supply unit and the first valve and for increasing the pressure of the inert gas supplied from the inert gas supply unit,
Wherein the control unit operates the compression unit such that the pressure of the inert gas supplied to the combustion chamber increases when the pressure of the combustion chamber measured by the measurement unit is equal to or higher than a preset reference combustion chamber pressure.

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