KR102442206B1 - Ship Engine and Method for Ship Engine - Google Patents

Abstract

The present invention provides a step of supplying scavenging air to a cylinder when the engine is operating, supplying an air mixed gas fuel in which gas fuel and auxiliary air are mixed to the cylinder while the piston moves from bottom dead center to top dead center, to the cylinder Measuring combustion pressure or acceleration of exhaust gas, detecting knocking or pre-ignition from the measured combustion pressure or acceleration of exhaust gas, and when knocking or pre-ignition is detected, the amount of air supplied to the cylinder is It relates to a marine engine and a marine engine control method comprising the step of increasing an injection period for supplying air to the cylinder to increase.

Description

Marine engine and ship engine control method {Ship Engine and Method for Ship Engine}

The present invention relates to a marine engine for propelling a vessel and a method for controlling the marine engine.

In general, marine engines include various engines such as a diesel engine, a gas turbine engine, and a dual fuel engine. In particular, the dual fuel engine has two fuels. For example, it is widely used in ships due to the advantage that gas and diesel can be used in parallel.

Such an engine is divided into a low pressure type engine and a high pressure type engine according to the pressure at which gas is supplied to the cylinder.

Low-pressure engines have low pressure gas in the middle of the cylinder. For example, by installing a gas supply valve capable of supplying 5 to 30 bar, and injecting gas in the middle of air compression to allow air and gas to be mixed in advance before ignition, pre-mixed combustion is possible.

In high-pressure engines, high-pressure gas is applied to the upper part of the cylinder. For example, a high output is generated by installing a fuel injection valve capable of supplying 300 Bar, compressing air, and then injecting fuel from the upper side for diffusion combustion.

However, since the engine according to the prior art supplies gas in an intermediate process of compressing air, the gas and air are not uniformly mixed. Accordingly, in the engine according to the prior art, not only the output is lowered, but abnormal combustion such as knocking and pre-ignition occurs, and the emission of nitrogen oxide (NOx), an environmental pollutant, is increased. have. In addition, there is a problem in that the engine efficiency is lowered by lowering the engine compression ratio in order to suppress the occurrence of knocking due to the premixed combustion. In particular, there is a problem in that the compression ratio lowered to suppress knocking in the gas mode using gas as fuel in the dual fuel engine deteriorates engine efficiency in the diesel mode using diesel as fuel. Therefore, it is urgently needed to develop a marine engine that can improve engine efficiency and increase engine service life by rapidly supplying additional air to the cylinder when knocking or pre-ignition occurs to prevent knocking or pre-ignition from occurring continuously. do.

The present invention has been devised to solve the above-described problems, and to provide a marine engine and a marine engine control method capable of rapidly supplying additional air to a cylinder when knocking or pre-ignition occurs.

In order to solve the problems as described above, the present invention may include the following configuration.

A marine engine according to the present invention includes a cylinder; a piston reciprocating in the cylinder; a fuel supply unit for supplying fuel to the cylinder; an auxiliary air supply unit for supplying auxiliary air together with the fuel of the fuel supply unit; a sensing unit for detecting knocking or pre-ignition occurring in the cylinder; and a control unit for controlling the fuel supply unit and the auxiliary air supply unit. The control unit may control the auxiliary air supply unit to increase the injection period during which the auxiliary air supply unit supplies air to the cylinder when the sensing unit detects knocking or early ignition.

In the marine engine according to the present invention, the sensing unit may provide a combustion pressure value obtained by measuring the combustion pressure of the cylinder to the control unit. The control unit may increase the air supply injection period of the auxiliary air supply unit to increase the amount of air supplied to the cylinder when the combustion pressure value measured by the sensing unit exceeds a preset reference combustion pressure range.

In the marine engine according to the present invention, the sensing unit may provide an acceleration value obtained by measuring the acceleration of the exhaust gas discharged from the cylinder to the control unit. The control unit may increase the air supply injection period of the auxiliary air supply unit to increase the amount of air supplied to the cylinder when the acceleration value measured by the sensing unit exceeds a preset reference acceleration range.

The marine engine according to the present invention may further include a scavenging air supply unit for supplying air to the cylinder from the lower side of the cylinder. The auxiliary air supply unit may supply air to the cylinder after the scavenging air supply unit supplies air to the cylinder.

In the marine engine according to the present invention, the fuel supply unit may be coupled to the auxiliary air supply unit. The auxiliary air supply unit may supply air to the fuel supplied from the fuel supply unit so that the air mixture gas fuel in which air and fuel are mixed is supplied to the cylinder.

In the marine engine according to the present invention, the auxiliary air supply unit is installed in an air supply means for supplying air to the cylinder, an air supply pipe connecting the air supply means and the cylinder, and the air supply pipe, and It may include an air supply valve that opens and closes the air supply pipe so that air is supplied to the cylinder. The fuel supply unit is installed in a fuel supply means for supplying fuel to the cylinder, a fuel supply pipe connecting the fuel supply means and the air supply pipe, and the fuel supply pipe to supply fuel to the air supply pipe. It may include a fuel supply valve for opening and closing the fuel supply pipe.

In the marine engine according to the present invention, the control unit allows the air supply valve and the fuel supply valve to respectively open and close the air supply pipe and the fuel supply pipe according to a rotation angle of a crankshaft installed to be connected to the piston. A supply valve and the fuel supply valve may be controlled.

In the marine engine according to the present invention, according to claim 7, wherein the control unit supplies the air supply valve and the fuel according to the acquisition mode for acquiring the rotation angle of the crankshaft, and the rotation angle of the crankshaft acquired in the acquisition mode It may include a control mode for adjusting the opening/closing timing of each valve.

In the marine engine according to the present invention, the controller is the air supply valve and the air supply valve so that the air supplied to the cylinder from the air supply pipe is stopped later than the fuel supplied from the fuel supply pipe to the air supply pipe. The fuel supply valve can be controlled.

In the marine engine according to the present invention, the control unit is the air supply valve and the fuel supply so that the air supplied from the air supply pipe to the cylinder is supplied at least earlier than the fuel supplied from the fuel supply pipe to the air supply pipe. You can control the valve.

The marine engine according to the present invention may include an exhaust valve coupled to the cylinder to be positioned above the cylinder, and opening and closing the cylinder so that exhaust gas generated by burning fuel in the cylinder is discharged. The controller may control the exhaust valve and the supply unit, but control the exhaust valve and the supply unit so that the air mixed gas fuel is supplied to the cylinder after the cylinder is closed.

The marine engine according to the present invention may include an exhaust valve coupled to the cylinder to be positioned above the cylinder, and opening and closing the cylinder so that exhaust gas generated by burning fuel in the cylinder is discharged. The control unit controls the exhaust valve, but in a gas mode in which the fuel is gas, the exhaust valve may control the exhaust valve such that the closing timing of closing the cylinder is later than in the diesel mode in which the fuel is diesel .

A marine engine control method according to the present invention includes the steps of supplying scavenging air to a cylinder when the engine is operated; supplying an air mixture gas fuel in which gas fuel and auxiliary air are mixed to the cylinder while the piston moves from bottom dead center to top dead center; measuring the combustion pressure of the cylinder or measuring the acceleration of exhaust gas; detecting knocking or pre-ignition from the measured combustion pressure or acceleration of exhaust gas; and when the knocking or pre-ignition is sensed, increasing an injection period for supplying air to the cylinder to increase the amount of air supplied to the cylinder.

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

The present invention is implemented to quickly additionally supply air to the cylinder when abnormal combustion such as knocking or pre-ignition occurs, so that the air and fuel inside the cylinder can be uniformly mixed, resulting in knocking and pre-ignition ) can be suppressed and the emission of environmental pollutants such as nitrogen oxides (NOx) can be reduced.

1 is a schematic block diagram of a marine engine according to the present invention;
2 is a schematic view of a marine engine according to the present invention;
3 is a schematic block diagram for explaining a fuel supply unit, an auxiliary air supply unit, a sensing unit, and a control unit in a marine engine according to the present invention;
4 is an enlarged cross-sectional view of part A of FIG. 2 for explaining a fuel supply valve and an air supply valve in a marine engine according to the present invention;
5 and 6 are schematic operating state diagrams for explaining the supply of air before fuel in the marine engine according to the present invention
7 and 8 are schematic operating state diagrams for explaining that the supply of air is stopped later than fuel in the marine engine according to the present invention.
9 is a schematic block diagram for explaining a control unit in a marine engine according to the present invention;
10 is a schematic graph showing the opening and closing timings of the air supply valve and the fuel supply valve in the marine engine according to the present invention;
11 and 12 are schematic operation state diagrams for explaining the supply of air mixture gas fuel after the exhaust valve closes the cylinder in the marine engine according to the present invention.
13 is a schematic graph showing the opening and closing timings of an exhaust valve, an air supply valve, and a fuel supply valve in a marine engine according to the present invention;
14 is a schematic graph showing the opening/closing timing of the exhaust valve according to the gas mode and the diesel mode in the marine engine according to the present invention;
15 is a schematic flowchart for explaining a method for controlling a marine engine according to the present invention;

It should be noted that in the present specification, in adding reference numbers to the components of each drawing, the same numbers are used for the same components, even if they are indicated on different drawings, as much as possible.

On the other hand, the meaning of the terms described in this specification should be understood as follows.

The singular expression is to be understood as including the plural expression unless the context clearly defines otherwise, and the terms "first", "second", etc. are used to distinguish one element from another, The scope of rights should not be limited by these terms.

It should be understood that terms such as “comprise” or “have” do not preclude the possibility of addition or existence of one or more other features or numbers, steps, operations, components, parts, or combinations thereof.

The term “at least one” should be understood to include all possible combinations from one or more related items. For example, the meaning of "at least one of the first, second, and third items" means 2 of the first, second, and third items as well as each of the first, second, or third items. It means a combination of all 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 16, the marine engine 1 according to the present invention rapidly supplies air to the cylinder when abnormal combustion such as knocking or premature ignition occurs, thereby uniformly mixing the air and fuel inside the cylinder. Therefore, it is possible to suppress the occurrence of knocking and pre-ignition, and to reduce the emission of environmental pollutants such as nitrogen oxides (NOx). The marine engine 1 according to the present invention may be a two-stroke dual fuel engine, but is not necessarily limited thereto. The knocking is a phenomenon in which a sound similar to a hammer is generated due to abnormal combustion in a cylinder. The pre-ignition is a phenomenon in which the piston is ignited before reaching top dead center as one of abnormal combustion.

To this end, the marine engine (1) according to the present invention is largely a cylinder (2), a piston (3), a fuel supply unit (4), an auxiliary air supply unit (5), a control unit (6), and a sensing unit (7) includes

The cylinder 2 provides space for burning fuel. The piston 3 may reciprocate between the bottom dead center and top dead center in the cylinder 2 . The fuel supply unit 4 is for supplying fuel to the cylinder 2 . The auxiliary air supply unit 5 is for supplying auxiliary air together with the fuel of the fuel supply unit 4 . The sensing unit 7 is for detecting knocking or pre-ignition occurring in the cylinder 2 . The control unit 6 is for controlling the fuel supply unit 4 and the auxiliary air supply unit 5 . The control unit 6 controls the auxiliary air supply unit ( 5) can be controlled. Accordingly, the marine engine 1 according to the present invention prevents the engine efficiency from being lowered by rapidly supplying additional air to the cylinder 2 when knocking or pre-ignition occurs, thereby preventing knocking or pre-ignition from occurring continuously. Not only can it be prevented, but also it is possible to prevent an increase in the maintenance cost and replacement cost of the engine by extending the service life of the engine.

Hereinafter, the accompanying drawings for the cylinder (2), the piston (3), the fuel supply unit (4), the auxiliary air supply unit (5), the control unit (6), and the sensing unit (7) It will be described in detail with reference.

Cylinder 2 provides space for burning fuel. The cylinder 2 may be formed inside the engine block 100 (shown in FIG. 4 ). The cylinder 2 may be formed in a cylindrical shape with an empty interior. A cylinder liner 2a (shown in FIG. 4 ) may be installed between the cylinder 2 and the engine block 100 . A piston 3 may be movably installed in the cylinder 2 . For example, the piston 3 may reciprocate in the vertical direction based on the Y-axis direction (shown in FIG. 2 ) inside the cylinder 2 . A fuel supply unit 4 for supplying fuel, an auxiliary air supply unit 5 for supplying air, and a scavenging air supply unit 8 to be described later may be coupled to the cylinder 2 . Accordingly, the cylinder 2 may receive fuel from the fuel supply unit 4 , and may receive air from the auxiliary air supply unit 5 and the scavenging air supply unit 8 . The auxiliary air supply unit 5 may supply auxiliary air to the cylinder 2 after the scavenging air supply unit 8 supplies the scavenging air from the lower side of the cylinder 2 to the cylinder 2 . . The cylinder 2 may increase or decrease in volume as the piston 3 reciprocates. For example, the volume of the cylinder 2 may be reduced when the piston 3 moves upward. In this case, the fuel and air supplied to the cylinder 2 can be compressed. When the piston 3 moves from the first position (P1, shown in FIG. 2) to the second position (P2, shown in FIG. 2), a micropilot injector (not shown) installed on the upper side of the cylinder 2 ) by supplying diesel to ignite the compressed fuel, fuel and air are combusted and exploded to move the piston 3 downward. Accordingly, a driving force may be generated, and exhaust gas may be generated in the cylinder 2 . The first position P1 is when the piston 3 is located at the bottom dead center. The second position P2 is when the piston 3 is located at top dead center. The cylinder 2 can increase in volume when the piston 3 moves in the downward direction. When the piston 3 moves toward the bottom dead center, the scavenging air may be supplied to the cylinder 2 by the scavenging air supply unit 8 . Accordingly, the exhaust gas generated in the cylinder 2 may be discharged to the outside of the cylinder 2 by the scavenging air supplied from the scavenging air supply unit 8 . The exhaust gas may be naturally discharged to the outside of the cylinder 2 due to the high temperature. Exhaust gas may be discharged to the outside along the exhaust pipe coupled to the cylinder (2).

The piston 3 is for compressing the fuel and air supplied to the cylinder 2 . The piston (3) is movably installed in the cylinder (2). The piston 3 may reciprocate in the vertical direction inside the cylinder 2 . The piston 3 may be formed in a cylindrical shape, but may be formed in another shape as long as it can compress fuel and air while moving inside the cylinder 2 . The piston 3 may move upward by a crankshaft (not shown) that transmits a driving force. The piston 3 may be connected to the crankshaft through a rod-shaped piston rod and a connecting rod. The piston 3 can compress fuel and air when moving upward by the crankshaft. The piston 3 may move downward as the fuel and air supplied to the cylinder 2 are mixed and combusted at top dead center P2 and exploded. Accordingly, the piston 3 may reciprocate between the bottom dead center P1 and the top dead center P2 inside the cylinder 2 . The bottom dead center (P1) is a point at which the piston (3) is located at the lowest position inside the cylinder (2) with respect to the Y-axis direction. The top dead center 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 may explode the compressed fuel to generate a driving force when the piston 3 reaches top dead center P2.

The fuel supply unit 4 and the auxiliary air supply unit 5 are for supplying fuel and auxiliary air to the cylinder 2, respectively. The fuel supply unit 4 and the auxiliary air supply unit 5 may be coupled to the sidewall of the cylinder 2 , respectively. The supply unit 4 may supply air to the cylinder 2 when the piston 3 moves from the top dead center P2 to the bottom dead center P1. In this case, the supply unit 4 may supply air from the lower side of the cylinder 2 . The scavenging air supply unit 8 may supply scavenging air to the cylinder 2 when the piston 3 moves from the bottom dead center P1 to the top dead center P2. The scavenging air supply unit 8 may supply scavenging air from the lower side of the cylinder 2 . The fuel supply unit 4 and the auxiliary air supply unit 5 may supply fuel and auxiliary air to the cylinder 2, respectively, when the piston 3 moves from the bottom dead center P1 to the top dead center P2. In this case, the air mixture gas fuel (AF, shown in FIG. 3 ) in which auxiliary air and fuel are mixed may be supplied to the cylinder 2 . The fuel supply unit 4 and the auxiliary air supply unit 5 may supply the air mixed gas fuel AF to the cylinder 2 between the lower side and the upper side of the cylinder 2 . A marine engine (1) according to the present invention is a process in which the piston (3) compresses fuel and air. That is, since the air mixed gas fuel (AF) in which auxiliary air and fuel are mixed in advance can be supplied to the cylinder 2 in the middle of the piston 3 moving from the bottom dead center P1 to the top dead center P2, the compression process In comparison with the case where only fuel is supplied to the cylinder 2, the air and fuel inside the cylinder 2 can be uniformly mixed. Therefore, since the marine engine 1 according to the present invention can improve the combustion efficiency of the air mixture fuel, it is possible to prevent the output for propulsion of the ship from being lowered as well as to prevent the occurrence of knocking. can do. The fuel supply unit 4 may include a fuel supply means 4a, a fuel supply pipe 4b and a fuel supply valve 4c. The auxiliary air supply unit 5 may include an air supply means 5a, an air supply pipe 5b and an air supply valve 5c. The fuel supply means (4a) included in the fuel supply unit (4), the fuel supply pipe (4b), the fuel supply valve (4c), and the air supply means included in the auxiliary air supply unit (5) (5a), the description of the air supply pipe (5b), the air supply valve (5c) will be described after the description of the scavenging air supply unit (8).

2 to 8 , the marine engine 1 according to the present invention may include a scavenging air supply unit 8 .

The scavenging air supply unit 8 is for supplying air to the cylinder 2 . The air supplied by the scavenging air supply unit 8 to the cylinder 2 is referred to as scavenging air. The scavenging air supply unit 8 may supply air to the cylinder 2 by sucking air from the outside or around the engine, but is not limited thereto, and if air can be supplied to the cylinder 2, the air stored in the air storage tank for storing air may be supplied to the cylinder (2). The scavenging air supply unit 8 may include a small air hole 8a (shown in FIG. 3 ). The small pores are holes formed on the lower side of the cylinder, and may be formed through the cylinder liner. The small pores 8a may be located at a lower position than the auxiliary air supply unit 5 in the Y-axis direction. Accordingly, the piston (3) can sequentially move from the bottom dead center (P1) to the small pore (8a), the auxiliary air supply unit (5) and the top dead center (P2) to compress the air and fuel in the cylinder (2). have. Hereinafter, the case where the piston 3 is located in the small pore 8a is the third position (P3, shown in FIG. 4 ), and the case where the piston 3 is located in the auxiliary air supply unit 5 is the fourth case It is called a position (P4, shown in FIG. 4). The upper surface of the piston 3 may be located at the first position P1 , the second position P2 , the third position P3 , and the fourth position P4 . A plurality of the small pores 8a may be formed to be spaced apart from each other along the circumference of the cylinder liner 2a forming the cylinder 2 . The scavenging air supply unit 8 may supply air to the cylinder 2 at a pressure of about 1 bar - 8 bar depending on the engine load. Preferably, the scavenging air supply unit 8 may supply air to the cylinder 2 at a pressure of about 1 bar - 5 bar depending on the engine load. The scavenging air supply unit 8 may or may not supply air to the cylinder 2 by communicating with the cylinder 2 or blocking the communication according to the movement of the piston 3 . For example, when the piston 3 moves downward toward the bottom dead center rather than the small air hole 8a with respect to the Y-axis direction, the scavenging air supply unit 8 may communicate with the cylinder 2 . That is, when the piston 3 is positioned between the third position P3 and the first position P1 , the scavenging air supply unit 8 may communicate with the cylinder 2 . Accordingly, the scavenging air supply unit 8 may supply air to the cylinder 2 . For example, when the piston 3 moves upward toward the top dead center rather than the scavenge hole 8a in the Y-axis direction, the scavenging air supply unit 8 may block communication with the cylinder 2 . That is, when the piston 3 is positioned between the third position P3 and the second position P2 , the scavenging air supply unit 8 cannot communicate with the cylinder 2 . Accordingly, the scavenging air supply unit 8 cannot supply air to the cylinder 2 . A scavenging air supply unit 8 and an auxiliary air supply unit 5 may supply air to the cylinder 2 . The scavenging air supply unit 8 and the auxiliary air supply unit 5 may supply air to the cylinder 2 by dividing it. For example, if the total amount of air supplied to the cylinder 2 is 100, the scavenging air supply unit 8 may supply 90, and the auxiliary air supply unit 5 may supply 10. The air supplied by the auxiliary air supply unit 5 may be mixed with the fuel supplied from the fuel supply unit 4 and supplied to the cylinder 2 as an air mixture gas fuel (AF, shown in FIG. 3 ). The scavenging air supply unit 8 may further include an air storage chamber (not shown) for storing air to inject air into the cylinder 2 . A description of the air storage chamber will be described later.

The auxiliary air supply unit (5) is for supplying air to the cylinder (2). The air supplied by the auxiliary air supply unit 5 to the cylinder 2 is referred to as auxiliary air. The auxiliary air supply unit 5 may supply air to the cylinder 2 by sucking air from the outside or around the engine, but is not limited thereto, and if air can be supplied to the cylinder 2, air stored in an air storage tank for storing air may be supplied to the cylinder (2). The auxiliary air supply unit 5 may be coupled to the cylinder 2 . In this case, the auxiliary air supply unit 5 may be installed in the engine block 22 so as to be located between the upper side and the lower side of the cylinder (2). Accordingly, the auxiliary air supply unit 5 may supply auxiliary air to the cylinder 2 between the upper and lower sides of the cylinder 2 . The auxiliary air supply unit 5 may supply auxiliary air to the cylinder 2 until the piston 3 moves from the third position P3 to the fourth position P4. Since the scavenging air supply unit 8 can supply scavenging air to the cylinder 2 until the piston 3 moves from the first position P1 to the third position P3, the auxiliary air supply unit 5 After the scavenging air supply unit 8 supplies the scavenging air to the cylinder 2 , auxiliary air may be supplied to the cylinder 2 . Auxiliary air supply unit (5) is also the auxiliary air when fuel is supplied from the fuel supply unit (4) to the cylinder (2) in the middle of the piston (3) moving from the bottom dead center (P1) to the top dead center (P2). can supply In this case, the cylinder 2 may be closed by an exhaust valve 9 to be described later. In the marine engine 1 according to the present invention, the timing at which the scavenging air supply unit 8 supplies scavenging air to the cylinder 2 and the timing at which the auxiliary air supply unit 5 supplies auxiliary air to the cylinder 2 are determined. can be accurately distinguished. Therefore, the marine engine 1 according to the present invention can easily adjust the ratio of the air supplied to the cylinder 2 by the scavenging air supply unit 8 and the auxiliary air supply unit 5 . The auxiliary air supply unit 5 may not supply auxiliary air to the cylinder 2 when the piston 3 moves beyond the fourth position P4 toward the second position P2. In this case, the auxiliary air supply unit (5) is because the communication with the cylinder (2) is blocked by the movement of the piston (3). The auxiliary air supply unit 5 may include an air supply means 5a, an air supply pipe 5b and an air supply valve 5c.

The marine engine 1 according to the present invention may further include an additional air supply unit 10 (shown in FIG. 12 ).

The additional air supply unit 10 is for supplying air to the cylinder 2 . The additional air supply unit 10 may supply air to the cylinder 2 by additionally supplying air to at least one of the scavenging air supply unit 8 and the auxiliary air supply unit 5 . The air supplied by the additional air supply unit 10 to the cylinder 2 is referred to as additional air. The additional air supply unit (10) is one of the scavenging air supply unit (8) and the auxiliary air supply unit (5) when the sensing unit (7) detects knocking or pre-ignition occurring in the cylinder (2). At least one may be supplied with additional air. The additional air supply unit 10 may be coupled to the scavenging air supply unit 8 and the auxiliary air supply unit 5 by a hose or a pipe. When the additional air supply unit 10 supplies the additional air to the scavenging air supply unit 8 , the additional air supply unit 10 allows the scavenging air supply unit 8 to supply the scavenging air to the cylinder 2 . Additional air can be supplied together with the supply. When the additional air supply unit 10 supplies additional air to the auxiliary air supply unit 5 , the additional air supply unit 10 provides the auxiliary air supply unit 5 to the cylinder 2 with auxiliary air. Additional air can be supplied together with the supply. The additional air supply unit 10 may supply additional air to both the scavenging air supply unit 8 and the auxiliary air supply unit 5 . In this case, the additional air supply unit 10 may supply the additional air to the auxiliary air supply unit 5 after supplying the additional air to the scavenging air supply unit 8 . Accordingly, the marine engine 1 according to the present invention may supply at least one of scavenging air, auxiliary air, and additional air to the cylinder 2 when knocking or early ignition occurs. In the marine engine (1) according to the present invention, when the additional air supply unit (10) supplies additional air to the auxiliary air supply unit (5), the additional air supply unit (10) is the scavenging air supply unit Responsiveness can be further improved compared to the case of supplying to (8). This is because the scavenging air supply unit 8 supplies scavenging air from the lower side of the cylinder 2, while the auxiliary air supply unit 5 supplies auxiliary air from the middle part of the cylinder 2 . The additional air supply unit 10 may be installed inside the engine block 100, but is not limited thereto and may supply additional air to at least one of the scavenge air supply unit 8 and the auxiliary air supply unit 5. If possible, it may be installed outside the engine block 100 or installed at another location. The additional air supply unit 10 may be a compression device such as a compressor or blower or a compressed air storage tank such as a starting air receiver for storing starting air, but is not limited thereto, and the scavenge air supply unit 8 and the auxiliary As long as it can supply additional air to at least one of the air supply units 5, it may be another device. When the additional air supply unit 10 is a starting air receiver, the additional air supply unit 10 supplies the starting air stored in the starting air receiver to at least one of the scavenging air supply unit 8 and the auxiliary air supply unit 5 . It may further include an on/off valve for supplying or shutting off the . Since the starting air receiver stores the starting air in a compressed state, it is possible to quickly supply or block additional air only by opening or closing the opening/closing valve. The additional air supply unit 10 supplies additional air to the auxiliary air supply unit 5 until the piston 3 moves from the third position P3 to the fourth position P4, whereby the auxiliary air Additional air may be supplied to the cylinder 2 together with the auxiliary air supplied by the supply unit 411 . Since the scavenging air supply unit 8 can supply scavenging air to the cylinder 2 until the piston 3 moves from the first position P1 to the third position P3, the auxiliary air supply unit 5 And the additional air supply unit 10 may supply auxiliary air and additional air to the cylinder 2 after the scavenging air supply unit 8 supplies the scavenging air to the cylinder 2 . The auxiliary air supply unit (5) and the additional air supply unit (10) are fueled from the fuel supply unit (4) to the cylinder (2) while the piston (3) moves from the bottom dead center (P1) to the top dead center (P2). Auxiliary air and additional air can be supplied together when is supplied. In this case, the cylinder 2 may be closed by an exhaust valve to be described later. In the marine engine 1 according to the present invention, the timing at which the scavenging air supply unit 8 supplies scavenging air to the cylinder 2, the timing at which the auxiliary air supply unit 5 supplies auxiliary air to the cylinder 2, And it is possible to accurately distinguish the timing at which the additional air supply unit 10 supplies the additional air to the cylinder (2). Therefore, the marine engine 1 according to the present invention easily adjusts the ratio of the air supplied to the cylinder 2 by the scavenging air supply unit 8 , the auxiliary air supply unit 5 and the additional air supply unit 10 . can The auxiliary air supply unit 5 and the additional air supply unit 10 supply auxiliary air and additional air to the cylinder 2 when the piston 3 moves beyond the fourth position P4 toward the second position P2. may not be supplied. In this case, this is because the auxiliary air supply unit 5 and the additional air supply unit 10 are blocked from communicating with the cylinder 2 by the movement of the piston 3 .

The air supply means (5a) is for supplying auxiliary air to the cylinder (2). The air supply means (5a) may be coupled to the air supply pipe (5b). The air supply means (5a) may supply air to the cylinder (2) through the air supply pipe (5b). The air supply means (5a) may supply auxiliary air to the cylinder (2) by sucking in external air, but is not limited thereto, and if auxiliary air can be supplied to the cylinder (2), the air stored in the air storage tank for storing air may be supplied to the cylinder (2). For example, the air supply means 5a may be at least one of a compressor, an impeller, and a pump. The air storage tank may supply auxiliary air to the cylinder 2 through the air supply pipe 5b by compressing and storing air. The air supply means 5a may be connected to the additional air supply unit 10 by a hose or a pipe. When the additional air supply unit 10 supplies additional air to the air supply means 5a , the air supply means 5a may supply auxiliary air and additional air to the cylinder 2 .

The air supply pipe (5b) may have one side coupled to the air supply means (5a), and the other side coupled to the cylinder (2). The air supply pipe (5b) is for moving auxiliary air or auxiliary air mixed with auxiliary air and auxiliary air mixed with additional air, and may be a flow path such as a pipe or a pipe. The air supply pipe 5b may be coupled to the cylinder liner 2a to communicate with the cylinder 2 . Accordingly, the air supply pipe (5b) can move the auxiliary air supplied from the air supply means (5a), or the additional air mixed with the auxiliary air mixed with the auxiliary air to the cylinder (2). An air supply valve 5c may be installed in the air supply pipe 5b.

The air supply valve (5c) is for opening and closing the air supply pipe (5b). The air supply valve 5c may be a ball valve which is a rotary valve, but is not limited thereto, and if the air supply pipe 5b can be opened and closed, a gate valve that closes the valve by pushing the valve into the pipe, a globe that closes or closes the valve on the pipe It may be another valve, such as a valve. The air supply valve 5c may be rotatably coupled to the engine block 100 to open and close the air supply pipe 5b. When the air supply valve 5c is a ball valve, the air supply valve 5c may be rotated clockwise or counterclockwise based on a direction parallel to the X-axis direction (shown in FIG. 4 ). The X-axis direction may be a direction parallel to the floor, but is not limited thereto. The air supply valve 5c may be connected to the control unit 6 to be described later by at least one of wired communication and wireless communication. Accordingly, the air supply valve (5c) is rotated by the control unit (6), it is possible to open and close the air supply pipe (5b). For example, when the air supply valve 5c rotates clockwise, the air supply pipe 5b may be opened. Accordingly, auxiliary air can be supplied from the air supply means (5a) to the cylinder (2). In this case, the air supply means 5a may supply air at a pressure greater than the internal pressure of the cylinder 2 so that auxiliary air is supplied to the cylinder 2 . When the air supply valve (5c) is rotated counterclockwise, it can close the air supply pipe (5b). Accordingly, auxiliary air may not be supplied to the cylinder 2 . The air supply valve 5c may rotate clockwise to close the air supply pipe 5b, and rotate counterclockwise to open the air supply pipe 5b.

3 to 6 , the fuel supply unit 4 is for supplying fuel to the cylinder 2 . The fuel supply unit 4 may be coupled to the auxiliary air supply unit 5 . Accordingly, the fuel supply unit 4 may supply fuel to the cylinder 2 by supplying fuel to the auxiliary air supply unit 5 . The fuel supply unit 4 may supply fuel to the cylinder 2 until the piston 3 moves from the third position P3 to the fourth position P4 . In this case, the cylinder 2 may be closed by an exhaust valve 9 to be described later. By supplying fuel to the auxiliary air supply unit 5 by the fuel supply unit 4 , the auxiliary air supplied by the auxiliary air supply unit 5 and the fuel supplied by the fuel supply unit 4 are mixed in the cylinder 2 . Air mixed gas fuel (AF) may be supplied. When the additional air supply unit (10) supplies additional air to the auxiliary air supply unit (5), the fuel supplied by the fuel supply unit (4) to the cylinder (2), the auxiliary air supply unit (5) The auxiliary air supplied, and the additional air supplied by the additional air supply unit 10 are mixed air mixed gas fuel (AF) may be supplied. In this case, the pressure of the air mixture fuel (AF) supplied to the cylinder 2 may be between about 3 bar and 30 bar depending on the engine load, but preferably between 5 bar and 22 bar. It may be between bars. In this case, the pressure of the auxiliary air supplied by the auxiliary air supply unit 5 may be relatively lower than the supply pressure of the gas fuel supplied by the fuel supply unit 4 . This is to facilitate the supply of gas fuel to the cylinder 2 . When the pressure of the air mixed gas fuel (AF) exceeds 30 bar (bar), the capacity of each of the auxiliary air supply unit 5, the additional air supply unit 10 and the fuel supply unit 4 must be increased, so that the overall engine There is a problem with increasing the size. When the pressure of the air mixed gas fuel (AF) is less than 3 bar (bar), the problem that the air mixed gas fuel (AF) is not smoothly supplied to the cylinder (2) due to the pressure of the scavenging air supplied to the cylinder (2) there is The fuel supply unit 4 may not supply fuel to the auxiliary air supply unit 5 when the piston 3 is positioned at the fourth position P4 . This is because the communication between the cylinder 2 and the air supply pipe 5b is blocked. The fuel supply unit 4 may include a fuel supply means 4a, a fuel supply pipe 4b and a fuel supply valve 4c.

The fuel supply means 4a is for supplying fuel to the cylinder 2 . The fuel supply means (4a) may be coupled to the fuel supply pipe (4b). The fuel supply pipe (4b) may be coupled to the air supply pipe (5b). Accordingly, the fuel supply means 4a may supply fuel to the cylinder 2 by supplying fuel to the air supply pipe 5b through the fuel supply pipe 4b. The fuel supply means 4a may include a fuel storage tank for storing fuel, and a fuel transfer device for generating a transfer force for transferring the fuel stored in the fuel storage tank. For example, the fuel may be natural gas (NG). The fuel transfer device may supply fuel to the fuel supply pipe 4b by compressing the fuel. In this case, the fuel supply means 4a may be at least one of a compressor, an impeller, and a pump. The fuel storage tank may supply fuel to the fuel supply pipe 4b by compressing and storing fuel. In this case, the fuel supply means 4a may not include a fuel transfer device.

One side of the fuel supply pipe 4b may be coupled to the fuel supply means 4a, and the other side may be coupled to the air supply pipe 5b. The fuel supply pipe 4b is for moving fuel, and may be a flow path such as a pipe or a pipe. The fuel supply pipe (4b) may be coupled to the air supply pipe (5b) to communicate with the air supply pipe (5b). Therefore, the fuel supply pipe (4b) can move the fuel supplied from the fuel supply means (4a) to the air supply pipe (5b). The fuel supply pipe (4b) may be coupled to the air supply pipe (5b) so as to be located above the air supply pipe (5b). The upper side may mean a direction opposite to the direction of gravity, but may be in another direction as long as the fuel can easily move from the fuel supply pipe 4b to the air supply pipe 5b. The fuel supply pipe (4b) may be coupled to the air supply pipe (5b) at a first angle from the upper side of the air supply pipe (5b). The first angle may be greater than 0° and less than 180°. Accordingly, the fuel moved through the fuel supply pipe 4b may be supplied to the air supply pipe 5b by gravity. Therefore, in the marine engine 1 according to the present invention, the fuel supply means 4a can lower the load for compressing the fuel in order to move the fuel to the air supply pipe 5b, so the service life of the fuel supply means 4a can be extended. A fuel supply valve 4c may be coupled to the fuel supply pipe 4b.

The fuel supply valve 4c is for opening and closing the fuel supply pipe 4b. The fuel supply valve 4c may be movably coupled to the engine block 100 . The fuel supply valve (4c) may be a gate valve that locks by pushing the valve into the fuel supply pipe (4b), but is not limited thereto. It could be another valve, such as a globe valve that shuts off or shuts off. When the fuel supply valve 4c is a gate valve, the fuel supply valve 4c may move up and down based on the Y-axis. The fuel supply valve 4c may be connected to the control unit 6 to be described later by at least one of wired communication and wireless communication, and may be controlled by the control unit 6 . The fuel supply valve 4c is moved in the vertical direction by the control unit 6 to open and close the fuel supply pipe 4b. For example, when the fuel supply valve 4c is moved downward, the fuel supply pipe 4b may be opened. In this case, the fuel supply pipe 4b and the air supply pipe 5b communicate with each other, so that fuel can be supplied from the fuel supply pipe 4b to the air supply pipe 5b. When the fuel supply valve 4c moves upward, it can close the fuel supply pipe 4b. In this case, communication between the fuel supply pipe 4b and the air supply pipe 5b may be blocked. Accordingly, fuel may not be supplied to the air supply pipe 5b.

2 to 12 , the marine engine 1 according to the present invention may include a sensing unit 7 .

The sensing unit 7 is for detecting knocking or pre-ignition occurring in the cylinder 2 . The sensing unit 7 may detect knocking or pre-ignition occurring in the cylinder 2 by measuring a combustion pressure generated when fuel is burned in the cylinder 2 . The sensing unit (7) is installed on the cylinder cover coupled to the upper side of the cylinder (2) inside the cylinder (2). That is, it is possible to measure the combustion pressure generated during fuel combustion in the combustion chamber. In this case, the sensing unit 7 may be a pressure sensor. The sensing unit 7 is installed on the cylinder cover to measure the acceleration value of the exhaust gas discharged from the cylinder 2 to detect knocking or pre-ignition occurring in the cylinder 2 . In this case, the sensing unit 7 may be an acceleration sensor. There may be one sensing unit 7, but a plurality of sensing units 7 may be installed at different positions such as a cylinder cover and a cylinder liner in order to increase the reliability of the combustion pressure or acceleration value. The sensing unit 7 may be connected to the control unit 6 by at least one of wireless communication and wired communication. Accordingly, the sensing unit 7 may provide the measured combustion pressure or acceleration information to the control unit 6 .

4 to 12 , the marine engine 1 according to the present invention may include a control unit 6 .

The control unit 6 is for controlling the fuel supply valve 4c, the air supply valve 5c and the additional air supply unit 10 .

First, looking at how the control unit 6 controls the fuel supply valve 4c and the air supply valve 5c, the control unit 6 is connected to the piston 3 according to the rotation angle of the crankshaft. The fuel supply valve 4c and the air supply valve 5c can be controlled. The control unit 6 may open or close the fuel supply pipe 4b by controlling the fuel supply valve 4c according to the rotation angle of the crankshaft. The control unit 6 may open or close the air supply pipe 5b by controlling the air supply valve 5c according to the rotation angle of the crankshaft. The control unit 6 may include an acquisition mode 61 and a control mode 62 .

The acquisition mode 61 is a mode for acquiring the rotation angle of the crankshaft. For example, in the acquisition mode 61, the control unit 6 may acquire the rotation angle of the crankshaft through an angle sensor installed on the crankshaft. The control unit 6 may acquire the rotation angle of the crankshaft through a governor that detects the rotational speed of the crankshaft, but is not limited thereto, and may acquire the rotation angle of the crankshaft through another device. The control unit 6 may be connected to an angle sensor, a governor, or the like through at least one of a wired device and a wireless device. Accordingly, in the case of the acquisition mode 61, the control unit 6 may acquire the rotation angle of the crankshaft from an angle sensor, a governor, or the like.

The control mode 62 is a mode for adjusting the opening/closing timing of each of the fuel supply valve 4c and the air supply valve 5c according to the rotation angle of the crankshaft obtained in the acquisition mode 61 . For example, in the control mode 62, the control unit 6 receives the rotation angle information of the crankshaft acquired in the acquisition mode 61 and controls the fuel supply valve 4c to open and close the fuel supply pipe 4b. have. When the fuel supply pipe 4b is opened, fuel may be supplied from the fuel supply pipe 4b to the air supply pipe 5b. In this case, the fuel may be natural gas (NG). When the fuel supply pipe (4b) is closed, the fuel supply from the fuel supply pipe (4b) to the air supply pipe (5b) may be blocked. For example, in the control mode 62, the control unit 6 receives the rotation angle information of the crankshaft acquired in the acquisition mode 61 and controls the air supply valve 5c to open and close the air supply pipe 5b. have. When the air supply pipe 5b is opened, air may be supplied from the air supply means 5a to the cylinder 2 along the air supply pipe 5b. When the air supply pipe (5b) is closed, the air supplied to the cylinder (2) from the air supply means (5a) along the air supply pipe (5b) can be blocked. The control unit 6 acquires the rotation angle of the crankshaft in the acquisition mode 61, and in the control mode 62, the fuel supply valve 4c and the air according to the rotation angle of the crankshaft acquired in the acquisition mode 61. The opening/closing timing of each of the supply valves 5c can be adjusted. When the control mode 62, the control unit 6 opens and closes each of the fuel supply valve 4c and the air supply valve 5c according to the preset rotation angle of the crankshaft, the rotation angle of the crankshaft acquired in the acquisition mode 61. By applying the timing data, the opening/closing timing of each of the fuel supply valve 4c and the air supply valve 5c can be adjusted. The opening/closing timing data of each of the fuel supply valve 4c and the air supply valve 5c according to the rotation angle of the crankshaft may be preset by an operator. The control unit 6 controls the air mixture gas fuel in which fuel and air are mixed to be supplied to the cylinder 2 while the piston 3 moves from the bottom dead center P1 to the top dead center P2 in the control mode 62 . The fuel supply valve 4c and the air supply valve 5c can be controlled. Specifically, when the piston 3 moves upward from the bottom dead center P1 and the air supplied from the scavenging air supply unit 8 to the cylinder 2 is blocked, the control unit 6 closes the air supply pipe 5b. The air mixture gas fuel supply to the cylinder 2 is started through the It is possible to control the fuel supply valve (4c) and the air supply valve (5c) to do so. That is, the control unit 6 may supply the air mixture gas fuel to the cylinder 2 until the piston 3 moves from the third position P3 to the fourth position P4 . Accordingly, the marine engine 1 according to the present invention can supply the air mixed gas fuel in which the air and fuel are mixed in advance to the cylinder 2 in the process of the piston 3 compressing the fuel and air, so that in the compression process Compared to a case where only fuel is supplied to the cylinder 2 , the air and fuel inside the cylinder 2 can be uniformly mixed. Therefore, since the marine engine 1 according to the present invention can improve the combustion efficiency of the air mixture fuel, it is possible to prevent the output for propulsion of the ship from being lowered as well as to prevent the occurrence of knocking. can do. In addition, since the marine engine 1 according to the present invention can supply air-mixed gas fuel in which air and fuel are mixed in the middle part of the cylinder 2, when air and fuel are separately supplied from the lower side of the cylinder 2 Since the compression ratio can be increased, engine efficiency can be improved.

4 to 12, the control unit 6 controls the air supplied from the air supply pipe 5b to the cylinder 2 later than the fuel supplied from the fuel supply pipe 4b to the air supply pipe 5b. The air supply valve 5c and the fuel supply valve 4c can be controlled so that the supply is stopped. Here, the fuel may be a gas. 10 is a schematic graph showing the opening and closing timings of the air supply valve and the fuel supply 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/closing timing of the air supply valve 5c. The second line L2 is a graph showing the opening/closing timing of the fuel supply valve 4c. In the graph, the upper direction of the vertical axis indicates that the fuel supply valve 4c and the air supply valve 5c respectively open the fuel supply pipe 4b and the air supply pipe 5b. In the graph, the downward direction of the vertical axis means that the fuel supply valve 4c and the air supply valve 5c close the fuel supply pipe 4b and the air supply pipe 5b, respectively. The control unit 6 controls the fuel supply valve 4c so that each of the fuel supply valve 4c and the air supply valve 5c periodically opens and closes the fuel supply pipe 4b and the air supply pipe 5b according to the rotation angle of the crankshaft. And it is possible to control the air supply valve (5c). Referring to FIG. 10 , the second line L2 is located inside the first line L1 . This means that after the air supply valve 5c opens the air supply pipe 5b first, the fuel supply valve 4c opens the fuel supply pipe 4b, and the fuel supply valve 4c opens the fuel supply pipe 4b. It means that the air supply valve (5c) closes the air supply pipe (5b) after closing.

First, looking at the closing timings of the air supply valve 5c and the fuel supply valve 4c, the control unit 6 closes the fuel supply pipe 4b according to a preset rotation angle of the crankshaft and then the air supply pipe 5b. The air supply valve 5c and the fuel supply valve 4c can be controlled so that this is closed. Accordingly, the air supplied to the cylinder 2 from the air supply pipe 5b can be stopped later than the fuel supplied from the fuel supply pipe 4b to the air supply pipe 5b. When the supply of the air mixture gas fuel supplied to the cylinder 2 is stopped, the marine engine 1 according to the present invention stops the fuel supply first and stops the air supply later, so that the fuel remains in the air supply pipe 5b can be prevented Accordingly, the marine engine 1 according to the present invention prevents the fuel remaining in the air supply pipe 5b from being additionally supplied to the cylinder 2, thereby preventing preignition from occurring. However, it can contribute to environmental protection by preventing the unburned fuel containing harmful substances such as nitrogen oxides (NOx) and sulfur oxides (SOx) from being discharged to the outside. In addition, in the marine engine 1 according to the present invention, when the supply of the air mixed gas fuel supplied to the cylinder 2 is stopped, the fuel supply is first stopped and the air supply is stopped later, so that the fuel is supplied to the air supply pipe 5b. It is possible to prevent the engine efficiency from being lowered by preventing it from remaining.

Next, looking at the opening timing of the air supply valve (5c) and the fuel supply valve (4c), the control unit (6) is the air supplied from the air supply pipe (5b) to the cylinder (2) is air from the fuel supply pipe (4b) The air supply valve 5c and the fuel supply valve 4c may be controlled to be supplied at least earlier than the fuel supplied to the supply pipe 5b. The control unit 6 may control the air supply valve 5c and the fuel supply valve 4c so that the fuel supply pipe 4b is opened after the air supply pipe 5b is opened according to the preset rotation angle of the crankshaft. . Accordingly, the air supplied from the air supply pipe 5b to the cylinder 2 may be supplied before the fuel supplied from the fuel supply pipe 4b to the air supply pipe 5b. The marine engine 1 according to the present invention supplies air before fuel when supplying air mixed gas fuel to the cylinder 2, thereby lowering the pressure of the air supply pipe 5b due to the flow rate of the air, thereby reducing the fuel supply pipe 4b. of the fuel may be sucked toward the air moving through the air supply pipe (5b). Accordingly, the marine engine 1 according to the present invention can uniformly mix fuel and air in the cylinder 2 by mixing air and fuel in advance in the air supply pipe 5b and supplying it to the cylinder 2, It is possible not only to reduce the generation of nitrogen oxides (NOx), which is an exhaust gas pollutant, but also to improve knocking and pre-ignition.

The controller 6 may control the air supply valve 5c and the fuel supply valve 4c so that the air supply pipe 5b and the fuel supply pipe 4b are simultaneously opened. The control unit 6 may control the air supply valve 5c and the fuel supply valve 4c so that the air supply pipe 5b and the fuel supply pipe 4b are simultaneously opened according to a preset rotation angle of the crankshaft. In this case, since fuel and air are simultaneously supplied to the air supply pipe 5b, air and fuel may be mixed and supplied to the cylinder 2 at the same time. Therefore, since the marine engine 1 according to the present invention can uniformly mix the air and fuel supplied to the cylinder 2, it is possible to reduce the generation of nitrogen oxides (NOx), which is an exhaust gas pollutant, Engine efficiency can be improved by improving knocking and pre-ignition.

Next, looking at how the control unit 6 controls the additional air supply unit 10, the control unit 6 controls the additional air supply unit 10 according to the detection unit 7 detecting knocking or pre-ignition. can be controlled. When the sensing unit 7 detects knocking or early ignition in the cylinder 2, the control unit 6 controls the additional air supply unit 10 to control the scavenge air supply unit 8 and the auxiliary air By supplying additional air to at least one of the supply units (5), it is possible to increase the overall amount of air supplied to the cylinder (2). For example, the control unit 6 receives the combustion pressure of the cylinder 2 from the sensing unit 7 , and operates the compression device or opens the on/off valve when the combustion pressure value exceeds a preset reference combustion pressure range. By opening it, it is possible to supply additional air to at least one of the scavenging air supply unit 8 and the auxiliary air supply unit 5 . In this case, the sensing unit 7 may be a pressure sensor. The reference combustion pressure range means a combustion pressure range in which knocking or pre-ignition does not occur in the cylinder 2, and may be preset by an operator. For example, the control unit 6 receives acceleration information of the exhaust gas discharged from the cylinder 2 from the sensing unit 7 , and operates the compression device when the acceleration value exceeds a preset reference acceleration range. By opening the on/off valve, additional air may be supplied to at least one of the scavenging air supply unit 8 and the auxiliary air supply unit 5 . In this case, the sensing unit 7 may be an acceleration sensor. The reference acceleration range means an acceleration range in which knocking or pre-ignition does not occur in the cylinder 2, and may be preset by an operator. When the sensing unit 7 detects knocking or pre-ignition in the cylinder 2 , the control unit 6 controls the additional air when the scavenging air supply unit 8 supplies the scavenging air to the cylinder 2 . The supply unit 10 may supply additional air to the scavenging air supply unit 8 . Accordingly, the cylinder 2 may receive the scavenging air and additional air from the scavenging air supply unit 8 . When the sensing unit 7 detects knocking or pre-ignition in the cylinder 2 , the control unit 6 controls the auxiliary air supply unit 5 to supply auxiliary air to the cylinder 2 when the auxiliary air is supplied to the cylinder 2 . The supply unit 10 may supply additional air to the auxiliary air supply unit 5 . Accordingly, the cylinder 2 may receive auxiliary air and additional air from the auxiliary air supply unit 5 . The control unit 6 supplies additional air to both the scavenging air supply unit 8 and the auxiliary air supply unit 5 when the sensing unit 7 detects knocking or early ignition in the cylinder 2 . may be In this case, the cylinder 2 may receive scavenging air and additional air from the scavenging air supply unit 8 , and may receive auxiliary air and additional air from the auxiliary air supply unit 5 . Accordingly, the marine engine 1 according to the present invention prevents the engine efficiency from being lowered by rapidly supplying additional air to the cylinder 2 when knocking or pre-ignition occurs, thereby preventing knocking or pre-ignition from occurring continuously. Not only can it be prevented, but also it is possible to prevent an increase in the maintenance cost and replacement cost of the engine by extending the service life of the engine.

The control unit 6 supplies additional air to the scavenging air supply unit 8 and the auxiliary air supply unit 5 when the sensing unit 7 does not detect knocking or pre-ignition in the cylinder 2 . It is possible to control the additional air supply unit 10 so as not to do so.

In the marine engine 1 according to the present invention, the scavenging air supply unit 8 may further include an air storage chamber (not shown). The air storage chamber may store air to supply air to the cylinder 2 . The air storage chamber may be formed in the engine block 100 to be located below the cylinder (2). The air storage chamber may be formed to be larger in size than the cylinder 2 so that the cylinder 2 is located inside. The air storage chamber may be in communication with the cylinder (2) at the lower side of the cylinder (2). Accordingly, the air storage chamber can supply air to the cylinder (2). When the piston 3 moves from the third position P3 to the first position P1 in the air storage chamber, the air storage chamber and the cylinder 2 communicate with each other to start supplying air to the cylinder 2 . The air storage chamber may supply air to the cylinder 2 by communicating with the air storage chamber and the cylinder 2 until the piston 3 moves from the first position P1 to the third position P3. When the piston 3 reaches the third position P3 in the air storage chamber, the communication between the air storage chamber and the cylinder 2 is blocked, so that air cannot be supplied to the cylinder 2 . The air storage chamber may receive air that has been sequentially passed through the compressor of the turbocharger, the air cooler, and the air receiver. The compressor of the turbocharger may compress air using engine exhaust gas as driving force. The air cooler may receive compressed air from a compressor to cool it. The air cooler may cool the compressed air by exchanging heat between the cooling medium and the compressed air, but is not limited thereto, and the compressed air may be cooled by other methods such as using a cooling device. The air receiver may receive cooled air from the air cooler. The air storage chamber may store air supplied from the air receiver. For example, the air storage chamber may store air at a pressure of about 1 bar - 8 bar depending on the engine load. Accordingly, the air storage chamber may supply air to the cylinder 2 at a pressure of about 1 bar - 8 bar. Preferably, the air storage chamber may supply air to the cylinder 2 at a pressure of 1 bar - 5 bar.

11 to 14 , the marine engine 1 according to the present invention may include an exhaust valve 9 .

The exhaust valve 9 may be movably coupled to the cylinder 2 based on the Y-axis direction. The exhaust valve 9 may be coupled to the engine block 100 so as to be located above the cylinder 2 . The exhaust valve 9 is for opening and closing the cylinder 2 so that exhaust gas generated by combustion of fuel and air is discharged from the cylinder 2 . The exhaust valve 9 may be connected to the control unit 6 by at least one of wired communication and wireless communication. Accordingly, the exhaust valve 9 can open and close the cylinder 2 by being moved by the control unit 6 . For example, the exhaust valve 9 is moved downward by the control unit 6 , so that the cylinder 2 and the exhaust pipe can communicate with each other. The exhaust pipe is a flow path for discharging exhaust gas to the outside. Accordingly, the exhaust valve 9 can open the cylinder 2 . In this case, the exhaust gas may be naturally discharged to the outside through the exhaust pipe due to high temperature, or when air is supplied to the inside of the cylinder 2, may be artificially discharged to the outside through the exhaust pipe by the pressure of the air. The exhaust valve 9 is moved upward by the control unit 6 , thereby blocking the cylinder 2 and the exhaust pipe. Accordingly, the exhaust valve 9 can close the cylinder 2 . When the exhaust valve 9 closes the cylinder 2 and the piston 3 moves toward top dead center, the air mixed gas fuel is supplied to the cylinder 2, and when the piston 3 moves further toward top dead center, the supplied air Mixed gas fuel can be compressed.

The control unit 6 includes an exhaust valve 9, an air supply valve 5c and a fuel supply valve 4c so that the air mixed gas fuel is supplied to the cylinder 2 after the exhaust valve 9 closes the cylinder 2 can control The controller 6 may control the exhaust valve 9 , the air supply valve 5c and the fuel supply valve 4c according to the acquisition mode 61 and the control mode 62 . The control unit 6 may control the exhaust valve 9, the air supply valve 5c, and the fuel supply valve 4c according to a preset rotation angle of the crankshaft. The third line L3 (shown in FIG. 13 ) is a graph showing the opening/closing timing at which the exhaust valve 9 opens and closes the cylinder 2 . The third line (L3) is the opening/closing timing for the exhaust valve 9 to open and close the cylinder 2 in the gas mode in which the fuel is gas, and the exhaust valve 9 to the cylinder 2 in the diesel mode in which the fuel is diesel. It is a graph that includes all the opening/closing timings for opening and closing the . The third line L3 is positioned to the left of the first line L1 and the second line L2 . This means that after the exhaust valve 9 opens and closes the cylinder 2 , the air supply valve 5c and the fuel supply valve 4c open and close the air supply pipe 5b and the fuel supply pipe 4b, respectively. The control unit 6 may close the cylinder 2 by controlling the exhaust valve 9 when the exhaust gas in the cylinder 2 is discharged to the outside. For example, the controller 6 may control the exhaust valve 9 to open the cylinder 2 while the piston 3 moves from the second position P2 to the first position P1 . The controller 6 may open the cylinder 2 until the piston 3 is positioned from the first position P1 to the third position P3. Accordingly, the exhaust gas generated in the cylinder 2 may be naturally discharged by high temperature or artificially discharged through the exhaust pipe by the scavenging air supplied through the scavenging air supply unit 8 . The control unit 6 may close the cylinder 2 when the piston 3 is positioned at the third position P3. When the cylinder 2 is closed, the controller 6 may control the air supply valve 5c and the fuel supply valve 4c to open the air supply pipe 5b and the fuel supply pipe 4b, respectively. Accordingly, the air mixture gas fuel (AF) in which fuel and air are mixed may be supplied to the cylinder 2 . Since the marine engine 1 according to the present invention can supply the air mixed gas fuel AF to the cylinder 2 after the cylinder 2 is closed, the methane slip through which the fuel flows to the outside of the cylinder 2 (Methane) slip) can be prevented. Therefore, the marine engine 1 according to the present invention can prevent environmental pollution by preventing environmental pollutants such as nitrogen oxides (NOx) and sulfur oxides (SOx) contained in fuel from leaking to the outside of the ship. Not only that, but it can also satisfy strict environmental regulations. In the sixth line (L6, shown in FIG. 13 ), when the sensing unit 7 detects knocking or pre-ignition in the cylinder 2 , the auxiliary air supply unit 5 sends air to the cylinder 2 . It is a graph showing increasing the injection period for supplying The sixth line L6 is larger than the first line L1 indicating the air supply injection period when knocking or pre-ignition does not occur. This means that the auxiliary air supply unit 5 supplies air to the cylinder 2 by pulling the injection timing more than the air supply injection timing when the knocking or pre-ignition does not occur, and delaying the air injection termination timing. This means that the injection period is increased. Therefore, the marine engine 1 according to the present invention can increase the amount of air by increasing the injection period for supplying air to the cylinder 2 when knocking or pre-ignition occurs, so that knocking or pre-ignition continuously occurs. This can be prevented, thereby prolonging the service life of the engine.

Referring to FIG. 14 , the control unit 6 closes the cylinder 2 by controlling the exhaust valve 9 according to the crankshaft rotation angle set differently depending on the gas mode in which the fuel is gas and the diesel mode in which the fuel is diesel. It is possible to adjust the closing timing of the exhaust valve (9). In this case, the marine engine 1 according to the present invention may be a dual fuel engine. Dual fuel engines have two fuels. For example, natural gas (NG) and diesel (MDO) may be mixed to generate an output for propelling a vessel. The dual fuel engine may include a diesel injector and a micro-pilot injector. The diesel injector and the micropilot injector may be installed in different positions of the cylinder 2 . The diesel injector is for injecting diesel (MDO) fuel into the compressed air cylinder 2 when the fuel is diesel (MDO) in the diesel mode. Accordingly, in the dual fuel engine, diesel fuel is ignited by compressed air to generate driving force. The micropilot injector is to ignite the gas fuel compressed in the cylinder (2) by injecting diesel oil into the cylinder (2) when the fuel is natural gas in the gas mode. The micropilot injector can ignite the compressed gas fuel by injecting a small amount of diesel oil into the cylinder when gas fuel and air are compressed. The diesel injector is for supplying diesel fuel to the cylinder 2 in the diesel mode, and the micropilot injector is for igniting the compressed gas fuel in the cylinder 2 in the gas mode. Accordingly, the amount of diesel supplied by the diesel injector to the cylinder 2 is greater than the amount of diesel supplied by the micropilot injector to the cylinder 2 . Referring to FIG. 14 , the fourth line L4 is a graph showing the opening/closing timing at which the exhaust valve 9 opens and closes the cylinder 2 in the diesel mode in which the fuel is diesel. The fifth line L5 is a graph showing the opening/closing timing at which the exhaust valve 9 opens and closes the cylinder 2 in the gas mode in which the fuel is gas. The fifth line L5 has a graph downward from the right side of the fourth line L4. This means that in the gas mode, the closing timing at which the exhaust valve 9 closes the cylinder 2 is later than in the diesel mode. In the gas mode, the controller 6 may control the exhaust valve 9 so that the closing timing for closing the cylinder 2 is later than when the exhaust valve 9 is in the diesel mode. The closing timing of the cylinder (2) is related to the compression pressure and compression temperature of the fuel and air supplied to the cylinder (2). That is, the closing timing of the cylinder 2 is related to the effective compression ratio of the fuel and air supplied to the cylinder 2 . The effective compression ratio refers to the actual compression ratio in the engine, and in a two-stroke engine, the volume ratio of the cylinder 2 at the moment when the scavenging air hole is closed and the volume ratio of the cylinder 2 when the piston 3 reaches top dead center. If the closing timing of the cylinder 2 is fast, the compression time at which the piston 3 compresses the fuel and air supplied to the cylinder 2 becomes faster, so that the compression pressure of the air and the fuel increases, and thus the compression temperature may be increased. When the closing timing of the cylinder 2 is slow, compared to the case where the closing timing of the cylinder 2 is fast, the compression time at which the piston 3 compresses the fuel and air supplied to the cylinder 2 becomes slower. The lower the pressure, the lower the compression temperature can be. In the marine engine 1 according to the present invention, the geometrical compression ratio of the gas mode and the diesel mode may be the same. The marine engine 1 according to the present invention can lower the compression temperature by lowering the compression pressure in the cylinder 2 compared to the diesel mode by delaying the closing timing of the cylinder 2 compared to the diesel mode when in the gas mode. In this case, the control unit 6 may delay the supply timing of the air mixture gas fuel supplied to the cylinder (2). Accordingly, the marine engine 1 according to the present invention lowers the effective compression ratio compared to the diesel mode in the gas mode, thereby lowering the compression temperature of the cylinder 2 and pre-igniting the piston 3 before reaching top dead center ( Preignition) can be prevented. Accordingly, since the marine engine 1 according to the present invention may have different effective compression ratios according to the gas mode and the diesel mode, the efficiency of the engine may be improved in the gas mode and the diesel mode, respectively. The control unit 6 may switch to a gas mode in which less harmful substances such as nitrogen oxides (NOx) and sulfur oxides (SOx) are emitted when the ship operates in the emission limiting area (ECA). The control unit 6 may switch to the diesel mode when the vessel operates the emission mitigation zone (Global). By adjusting the closing timing of the cylinder 2 of the exhaust valve 9 differently according to the gas mode and the diesel mode in the marine engine 1 according to the present invention, the efficiency of the engine can be improved without structural change of the cylinder 2 . .

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

15 is a schematic flowchart for explaining a method for controlling a marine engine according to the present invention.

1 to 15 , the marine engine control method according to the present invention may be performed by the marine engine 1 according to the present invention described above. A marine engine control method according to the present invention includes the following configuration.

First, scavenging air is supplied to the cylinder 2 (S100). This step (S100) may be accomplished by the scavenging air supply unit 8 supplying the scavenging air to the cylinder 2 under the control of the controller 6 . This step ( S100 ) may be performed after the engine is started. The scavenging air supply unit 8 may supply scavenging air to the cylinder 2 until the piston 3 reaches the third position P3. In this case, the piston 3 may be moved to the second position P2 to perform the compression process.

Next, the air mixture gas fuel (AF) is supplied to the cylinder (2) (S200). This step (S200) may be accomplished by the auxiliary air supply unit 5 and the fuel supply unit 4 supplying the air mixed gas fuel AF to the cylinder 2 under the control of the controller 6 . This step (S200) can be made in the middle of the piston (3) moving in the direction from the lower side to the upper side after the scavenging air is supplied to the cylinder (2). That is, the piston 3 can be made until it reaches the fourth position P4 from the third position P3.

Next, the combustion pressure of the cylinder 2 is measured (S300). This step (S300) may be accomplished by the sensing unit 7 measuring the pressure when the air mixture gas fuel injected into the cylinder 2 and the scavenging air are compressed and combusted. The sensing unit 7 may provide the measured combustion pressure information to the control unit 6 by at least one of wireless communication and wired communication. This step (S300) may be accomplished by the sensing unit 7 measuring the acceleration value of the exhaust gas discharged from the cylinder (2). The sensing unit 7 may provide the measured acceleration information of the exhaust gas to the control unit 6 by at least one of wireless communication and wired communication.

Next, it is determined whether knocking or pre-ignition has occurred in the cylinder 2 (S400). In this step (S400), the control unit 6 compares the combustion pressure value of the cylinder 2 provided from the sensing unit 7 with a preset reference combustion pressure range or the exhaust gas provided from the sensing unit 7 This can be achieved by comparing the acceleration value of , and a preset reference acceleration range.

Next, if it is not determined that knocking or pre-ignition has occurred in the cylinder 2, the process returns to the step of supplying scavenging air to the cylinder 2 (S100). Accordingly, the steps S200 and S300 may be repeatedly performed. The reason that knocking or pre-ignition did not occur in the cylinder 2 is that the combustion pressure value of the cylinder 2 provided by the control unit 6 from the sensing unit 7 is within or less than a preset reference combustion pressure range. case or the acceleration value of the exhaust gas provided from the sensing unit 7 may be within or less than a preset reference acceleration range.

Next, if it is determined that knocking or premature ignition has occurred in the cylinder 2, the auxiliary air supply injection period is increased (S500). In this step (S500), the control unit 6 determines that the combustion pressure value of the cylinder 2 provided from the sensing unit 7 exceeds a preset reference combustion pressure range or the acceleration value of the exhaust gas is within a preset reference acceleration range. When it exceeds, it is determined that knocking or early ignition has occurred, and the control unit 6 controls the auxiliary air supply unit 5 . Specifically, when it is determined that knocking or pre-ignition has occurred, the control unit 6 injects auxiliary air supplied by the auxiliary air supply unit 5 to the cylinder 2 rather than when knocking or pre-ignition does not occur. By increasing the period, it is possible to increase the amount of air supplied to the cylinder 2 . Therefore, the marine engine control method according to the present invention prevents the engine efficiency from being lowered by rapidly supplying auxiliary air to the cylinder 2 when knocking or pre-ignition occurs, thereby preventing knocking or pre-ignition from continuously occurring. In addition, it is possible to prevent an increase in maintenance cost and replacement cost for the engine by extending the service life of the engine.

A marine engine and a marine engine control method according to the present invention increase the air supply injection period during which the auxiliary air supply unit 5 supplies air to the cylinder 2 when knocking or early ignition occurs, thereby providing the cylinder 2 with Although it has been described as increasing the amount of supplied air, by supplying additional air to at least one of the scavenging air supply unit 8 and the auxiliary air supply unit 5 using the additional air supply unit 10, It is also possible to increase the amount of air supplied to the cylinder (2).

In addition, the marine engine and the marine engine control method according to the present invention have been described with one cylinder as an example, but in the case of a plurality of cylinders, the sensing unit 7, the auxiliary air supply unit 5 and the additional air supply unit ( 10) may be installed to further supply at least one of auxiliary air and additional air only to a cylinder in which knocking or pre-ignition occurs.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications, and changes are possible without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

1: Marine engine
2: cylinder 3: piston
4: fuel supply unit 5: auxiliary air supply unit
6: control unit 7: sensing unit
8: scavenging air supply unit 9: exhaust valve
10: additional air supply unit 61: acquisition mode
62: control mode

Claims (13)

cylinder;
a piston reciprocating in the cylinder;
a fuel supply unit for supplying fuel to the cylinder;
an auxiliary air supply unit for supplying auxiliary air together with the fuel of the fuel supply unit;
a sensing unit for detecting knocking or pre-ignition occurring in the cylinder; and
a control unit for controlling the fuel supply unit and the auxiliary air supply unit;
The control unit controls the auxiliary air supply unit to increase the injection period during which the auxiliary air supply unit supplies air to the cylinder when the sensing unit detects knocking or early ignition,
Further comprising a scavenging air supply unit for supplying air to the cylinder from the lower side of the cylinder,
The auxiliary air supply unit supplies air to the cylinder after the scavenging air supply unit supplies air to the cylinder,
In order to adjust the ratio of the air supplied to the cylinder by the scavenging air supply unit and the auxiliary air supply unit, the timing at which the scavenging air supply unit supplies the scavenging air to the cylinder and the auxiliary air supply unit to the cylinder A marine engine, characterized in that the timing of supplying auxiliary air is accurately distinguished. According to claim 1,
The sensing unit provides a combustion pressure value measured by the combustion pressure of the cylinder to the control unit,
The control unit increases the air supply injection period of the auxiliary air supply unit to increase the amount of air supplied to the cylinder when the combustion pressure value measured by the sensing unit exceeds a preset reference combustion pressure range. According to claim 1,
The sensing unit provides an acceleration value obtained by measuring the acceleration of the exhaust gas discharged from the cylinder to the control unit,
The control unit increases the air supply injection period of the auxiliary air supply unit to increase the amount of air supplied to the cylinder when the acceleration value measured by the sensing unit exceeds a preset reference acceleration range. delete According to claim 1,
The fuel supply unit is coupled to the auxiliary air supply unit,
The auxiliary air supply unit is a marine engine, characterized in that for supplying air to the fuel supplied from the fuel supply unit so that the air mixture gas fuel in which air and fuel are mixed is supplied to the cylinder. According to claim 1,
The auxiliary air supply unit is installed in an air supply means for supplying air to the cylinder, an air supply pipe connecting the air supply means and the cylinder, and the air supply pipe to supply air to the cylinder. Including an air supply valve for opening and closing the pipe,
The fuel supply unit is installed in a fuel supply means for supplying fuel to the cylinder, a fuel supply pipe connecting the fuel supply means and the air supply pipe, and the fuel supply pipe to supply fuel to the air supply pipe. Marine engine including a fuel supply valve for opening and closing the fuel supply pipe. 7. The method of claim 6,
The control unit controls the air supply valve and the fuel supply valve so that each of the air supply valve and the fuel supply valve opens and closes the air supply pipe and the fuel supply pipe according to a rotation angle of a crankshaft installed to be connected to the piston. Marine engine, characterized in that. The method of claim 6, wherein the control unit
an acquisition mode for acquiring the rotation angle of the crankshaft; and
and a control mode for adjusting the opening and closing timings of each of the air supply valve and the fuel supply valve according to the rotation angle of the crankshaft acquired in the acquisition mode. 7. The method of claim 6,
The control unit controls the air supply valve and the fuel supply valve so that the air supplied from the air supply pipe to the cylinder is stopped later than the fuel supplied from the fuel supply pipe to the air supply pipe. marine engine. 7. The method of claim 6,
The control unit controls the air supply valve and the fuel supply valve so that the air supplied from the air supply pipe to the cylinder is supplied at least earlier than the fuel supplied from the fuel supply pipe to the air supply pipe. engine. According to claim 1,
and an exhaust valve coupled to the cylinder so as to be located above the cylinder, and opening and closing the cylinder so that exhaust gas generated by combustion of fuel in the cylinder is discharged,
The control unit controls the exhaust valve, the fuel supply unit, and the auxiliary air supply unit, but the exhaust valve, the fuel supply unit and the auxiliary air supply so that the air mixed gas fuel is supplied to the cylinder after the cylinder is closed. A marine engine, characterized in that it controls the unit. According to claim 1,
and an exhaust valve coupled to the cylinder so as to be located above the cylinder, and opening and closing the cylinder so that exhaust gas generated by combustion of fuel in the cylinder is discharged,
The control unit controls the exhaust valve, and when the fuel is a gas mode, the exhaust valve controls the exhaust valve so that the closing timing for closing the cylinder is later than that of the diesel mode in which the fuel is diesel marine engine. supplying scavenging air to the cylinder from the lower side of the cylinder when the engine operates;
supplying an air mixture gas fuel in which gas fuel and auxiliary air are mixed to the cylinder while the piston moves from bottom dead center to top dead center;
measuring the combustion pressure of the cylinder or measuring the acceleration of exhaust gas;
detecting knocking or pre-ignition from the measured combustion pressure or acceleration of exhaust gas; and
When the knocking or pre-ignition is detected, increasing the injection period for supplying air to the cylinder to increase the amount of air supplied to the cylinder;
The step of supplying the air mixed gas fuel,
After the scavenging air is supplied to the cylinder, auxiliary air is supplied,
In order to control the rate at which the scavenging air and the auxiliary air are supplied to the cylinder, the timing of supplying the scavenging air to the cylinder and the timing of supplying the auxiliary air to the cylinder are accurately distinguished.

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