JP2015163795A - Two-cycle gas engine and fuel gas injection system for two-cycle gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-cycle gas engine capable of suppressing NOx (nitrogen oxide) generation by prompting premixing fuel gas with air.SOLUTION: A two-cycle gas engine comprises: a cylinder 2 and a cylinder head 3; a piston 4; a scavenging port 6; fuel gas injection means 8 injecting fuel gas into a combustion chamber c; and fuel-gas-injection-timing control means 12. The fuel gas injection means 8 includes a first fuel gas injector 8A injecting the fuel gas into the combustion chamber c when the piston 4 is located near a top dead center; and a second fuel gas injector 8B configured separately from the first fuel gas injection chamber 8A and injecting the fuel gas into the combustion chamber c when the piston 4 is located in front of the neighborhoods of the top dead center, and the second fuel gas injector 8B is configured to inject the fuel gas into the combustion chamber c at a lower injection pressure than that of the first fuel gas injector 8A.

Description

  The present invention relates to a two-cycle gas engine and a fuel gas injection system for the two-cycle gas engine.

  Conventionally, fuel gas such as natural gas is used as the main fuel, fuel oil such as light oil with good compression ignition is used as the pilot fuel, and the fuel oil is injected into the combustion chamber in a high temperature atmosphere and self-ignited. Gas engines that burn certain fuel gases are known.

  For example, Patent Document 1 discloses a dual fuel diesel engine in which a low cetane number fuel with poor compression ignitability such as fuel gas is used as a main fuel and fuel oil with good compression ignitability is used as a pilot fuel. The engine disclosed in Patent Document 1 includes a fuel gas injection valve and a pilot fuel injection valve provided in a cylinder head. The fuel gas and the pilot fuel are supplied from the fuel gas injection valve and the pilot fuel injection valve toward the combustion chamber. By injecting, the pilot fuel (fuel oil) is self-ignited in the high-temperature combustion chamber, thereby combusting the main fuel (fuel gas).

  Further, for example, Patent Document 2 discloses a gas engine in which a fuel gas having poor compression ignitability is used as a main fuel and diesel fuel such as light oil or kerosene having good compression ignitability is used as a pilot fuel. The gas engine of Patent Document 2 includes an intake port and a diesel fuel injection device provided in a cylinder head, and a fuel gas injection device provided on a cylinder peripheral wall. Then, air is introduced into the combustion chamber from the intake port during the intake stroke in which the piston descends, and fuel gas is injected into the combustion chamber from the fuel gas injection device at an appropriate time between the late stage of the intake stroke and the late stage of the compression stroke. It has become. The diesel fuel is injected from the diesel fuel injection device into the combustion chamber at the timing when the piston rises to near the top dead center, and the diesel fuel self-ignites in the combustion chamber so that the fuel gas as the main fuel is combusted. It is configured.

Japanese Utility Model Publication No. 62-45339 JP-A-6-137150

  By the way, in the engine of Patent Document 1 described above, the main fuel and the pilot fuel are supplied to the combustion chamber almost simultaneously near the top dead center, so that the main fuel injected into the combustion chamber is burned immediately without being agitated. The Therefore, the combustion form of the main fuel is diffusion combustion. In the case of diffusion combustion, there is a problem that uniform combustion is more difficult than in the case of premixed combustion, and NOx (nitrogen oxide) is likely to be generated in a high-temperature combustion region.

  The above-described gas engine of Patent Document 2 is an invention made to increase the amount of air taken into the combustion chamber. That is, while the invention of Patent Document 2 has conventionally introduced a mixture of fuel gas and air from the intake port, only air is sucked from the intake port and a separate fuel gas injection device is provided. It is configured. The fuel gas injection device injects fuel gas into the combustion chamber at a different timing from the intake stroke, thereby increasing the amount of air taken into the combustion chamber from the intake port, thereby improving the engine output. ing.

  Such Patent Document 2 does not disclose any technical idea of suppressing the generation of NOx (nitrogen oxide) by promoting premixing.

  The present invention has been made in view of the above-described problems of the prior art, and is a two-cycle gas engine that suppresses the generation of NOx (nitrogen oxide) by promoting the premixing of fuel gas and air, and The object is to provide a fuel gas injection system for a two-cycle gas engine.

  The two-cycle gas engine of the present invention is provided with a cylinder and a cylinder head, a piston that is housed in the cylinder, and that defines a combustion chamber between the peripheral wall of the cylinder and the cylinder head, and the cylinder head. A fuel gas injection means for injecting fuel gas into the combustion chamber; an ignition means provided in the cylinder head for igniting the fuel gas in the combustion chamber; and the piston opened to the peripheral wall of the cylinder. A scavenging port for supplying air into the combustion chamber when positioned in the vicinity of the point, and the fuel gas injection means when the piston is in the upward stroke and the piston is positioned 10 ° to 100 ° before top dead center Fuel gas is injected, and when the piston is located near top dead center, fuel gas is injected by the fuel gas injection means. And a fuel gas injection timing control means configured to ignite the fuel gas in the combustion chamber by the ignition means when the piston is located near the top dead center. And

  In the two-cycle gas engine of the present invention configured as described above, the fuel gas injection means for injecting the fuel gas into the combustion chamber, the ignition means for igniting the fuel gas in the combustion chamber, and the piston are located near the bottom dead center. A scavenging port for supplying air into the combustion chamber sometimes, and when the piston is positioned 10 ° to 100 ° before top dead center, fuel gas is injected by the fuel gas injection means, and when the piston is positioned near top dead center Fuel gas injection timing control means configured to inject fuel gas by the fuel gas injection means, and ignition timing control for igniting the fuel gas in the combustion chamber by the ignition means when the piston is located near top dead center Means.

  According to the present invention, fuel gas is injected when the piston is positioned 10 ° to 100 ° before top dead center, and fuel gas is injected when the piston is positioned near top dead center, and ignition is performed. Since the fuel gas in the combustion chamber is ignited by the means, the premixing of the fuel gas and air injected when the piston is positioned 10 ° to 100 ° before top dead center is promoted. . For this reason, the ratio of the diffusion combustion which occupies for the whole combustion falls, and generation | occurrence | production of NOx (nitrogen oxide) can be suppressed.

  In addition, such a two-cycle gas engine of the present invention can be configured only by controlling the fuel gas injection timing by means of a fuel gas injection timing control means constituted by, for example, an engine control unit (ECU). Therefore, it is possible to easily promote premixing in an existing two-cycle gas engine without requiring a new additional device or the like.

  Further, in the above invention, the fuel gas injection means is separate from the first fuel gas injection means for injecting fuel gas into the combustion chamber when the piston is located near top dead center, and the first fuel gas injection means. And a second fuel gas injection unit configured to inject fuel gas into the combustion chamber when the piston is positioned 10 ° to 100 ° before top dead center.

  Thus, if the fuel gas injection means is configured separately for the first fuel gas injection means and the second fuel gas injection means, the first fuel gas injection means and the second fuel gas injection means can The gas injection direction and pressure conditions can be made different. That is, when the piston is positioned 10 ° to 100 ° before top dead center and when the piston is near top dead center, the preferred fuel gas injection direction and the injection pressure are different. Therefore, by configuring the present invention in this way, it becomes possible to inject fuel gas into the combustion chamber with an optimal injection direction and injection pressure regardless of the position of the piston.

  The two-cycle gas engine of the present invention includes a cylinder and a cylinder head, a piston that is accommodated in the cylinder, and that defines a combustion chamber between the peripheral wall of the cylinder and the cylinder head, and the cylinder head A fuel gas injection means for injecting fuel gas into the combustion chamber; and a scavenging port that opens in a peripheral wall of the cylinder and supplies air into the combustion chamber when the piston is located near bottom dead center; The fuel gas is injected by the fuel gas injection means when the piston is in the ascending stroke and the piston is positioned near the top dead center, and the fuel gas injection is performed when the piston is positioned near the top dead center. And a fuel gas injection timing control means configured to inject fuel gas by the means. The fuel gas injection means is configured separately from the first fuel gas injection device and the first fuel gas injection device that inject fuel gas into the combustion chamber when the piston is located near top dead center. A second fuel gas injection device that injects fuel gas into the combustion chamber when the piston is positioned near the top dead center, and the second fuel gas injection device includes the first fuel gas injection The fuel gas is configured to be injected into the combustion chamber at an injection pressure lower than that of the apparatus.

  The two-cycle gas engine of the present invention includes a cylinder and a cylinder head, a piston that is accommodated in the cylinder, and that defines a combustion chamber between the peripheral wall of the cylinder and the cylinder head, and the cylinder head A fuel gas injection means for injecting fuel gas into the combustion chamber; and a scavenging port that opens in a peripheral wall of the cylinder and supplies air into the combustion chamber when the piston is located near bottom dead center; And a control device configured to control the fuel gas injection means. The control device causes the fuel gas injection means to inject fuel gas when the piston is in an ascending stroke and the piston is positioned in front of the top dead center, and further the piston is in the vicinity of the top dead center. A fuel gas is injected by the fuel gas injection means when positioned, and the fuel gas injection means injects fuel gas into the combustion chamber when the piston is located near top dead center An injection device and a second fuel gas injection device configured to inject fuel gas into the combustion chamber when the piston is positioned in front of the top dead center, separately from the first fuel gas injection device In addition, the second fuel gas injection device is configured to inject fuel gas into the combustion chamber at an injection pressure lower than that of the first fuel gas injection device.

  Further, in the above invention, further comprising an exhaust valve provided at the top of the cylinder head for opening and closing an exhaust port, the first fuel gas injection device is provided around the exhaust valve in the cylinder head, and the second The fuel gas injection device is provided around the exhaust valve in the cylinder head, and is formed by an injection direction of the fuel gas injected from the second fuel gas injection device and a direction orthogonal to the advancing / retreating direction of the piston. The angle can be configured to be larger than the angle formed by the injection direction of the fuel gas injected from the first fuel gas injection device and the direction orthogonal to the forward / backward direction of the piston.

  The fuel gas injection system for a two-cycle gas engine of the present invention is configured separately from the first fuel gas injection device configured to inject fuel gas into the combustion chamber and the first fuel gas injection device. And a fuel gas injection means having a second fuel gas injection device configured to inject fuel gas into the combustion chamber at an injection pressure lower than that of the first fuel gas injection device, and the piston is in an upward stroke. When the piston is positioned near the top dead center, fuel gas is injected by the second fuel gas injection device, and when the piston is positioned near the top dead center, the fuel is injected by the first fuel gas injection device. And a control device configured to inject the gas.

  According to the present invention, when the piston is positioned 10 ° to 100 ° before top dead center, the fuel gas is injected, and the premixing of the fuel gas and air is promoted so that the ratio of diffusion combustion in the entire combustion is increased. By reducing, it is possible to provide a two-cycle gas engine that suppresses the generation of NOx (nitrogen oxide) and a fuel gas injection system for the two-cycle gas engine.

It is the schematic for demonstrating the basic composition of the two-cycle gas engine of this invention. It is the schematic for demonstrating the basic composition of the two-cycle gas engine of this invention. 1 is a schematic diagram for explaining a two-cycle gas engine according to a first embodiment of the present invention. It is the schematic for demonstrating the 2-cycle gas engine concerning the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are merely illustrative examples and are not intended to limit the scope of the present invention only unless otherwise specified.

  1 and 2 are schematic views for explaining the basic configuration of the two-cycle gas engine of the present invention, wherein (a) is a top view and (b) is a cross-sectional view. First, the basic configuration of the two-cycle gas engine of the present invention will be described with reference to FIGS. 1 and 2.

  As shown in FIGS. 1 and 2, the two-cycle gas engine 1 of the present invention can move forward and backward within a cylindrical cylinder 2, a cylinder head 3 coupled to the upper end side of the cylinder 2, and the inside of the cylinder 2. And a piston 4 housed in the housing. A combustion chamber c is defined between the peripheral wall 2 a of the cylinder 2, the cylinder head 3, and the top surface 4 a of the piston 4. In addition, the code | symbol 5 in a figure has shown the piston ring.

  A scavenging port 6 is opened in the peripheral wall 2 a on the lower side of the cylinder 2. The scavenging port 6 is formed at a position above the top surface 4a of the piston 4 located near the bottom dead center (indicated by a two-dot chain line in the figure), and the piston 4 is located near the bottom dead center. Sometimes, air is supplied from the scavenging port 6 to the combustion chamber c. An exhaust port is opened at the top of the cylinder head 3 and an exhaust valve 7 for opening and closing the exhaust port is provided. The exhaust valve 7 is opened until the piston 4 reaches a position of about 100 ° before top dead center during the scavenging stroke when the piston 4 is in the upward stroke. The exhaust gas in the previous stroke remaining in the combustion chamber c is scavenged by the air supplied from the scavenging port 6 to the combustion chamber c.

  Further, as shown in FIG. 1, the cylinder head 3 is provided with a fuel gas injection device 8 (fuel gas injection means) for injecting a fuel gas 8a into the combustion chamber c. A fuel oil injection device 10 (ignition means) for injecting good fuel oil 10a is provided. The fuel gas injection device 8 and the fuel oil injection device 10 are respectively formed at two positions 180 degrees apart in the circumferential direction with the cylinder center o as the rotation center.

  In the present embodiment, the fuel gas injection device 8 and the fuel oil injection device 10 are each provided with four injection holes. In the present invention, the number of the fuel gas injection devices 8 and the fuel oil injection devices 10 described above is not particularly limited, and may be one, for example. However, in the present embodiment in which the exhaust valve 7 is provided at the top of the cylinder head 3, a plurality of fuel gas injection devices 8 and fuel oil injection devices 10 are arranged at equal intervals in the circumferential direction. Is preferred.

  The fuel gas injection device 8 and the fuel oil injection device 10 are connected to an engine control unit (ECU) 12 via a cable 14 as shown in FIGS. The ECU 12 is connected via a cable 16 to a crank angle sensor 15 that detects a rotation angle of the crankshaft 17. The phase of the piston 4 is detected by receiving a signal related to the rotation angle of the crankshaft 17 from the crank angle sensor 15. The fuel gas injection device 8 and the fuel oil injection device 10 are configured to inject the fuel gas 8a and the fuel oil 10a into the combustion chamber c at a predetermined timing based on a signal transmitted from the ECU 12. As shown in FIG. 1, when the piston 4 is located near the top dead center, the fuel gas 8a and the fuel oil 10a are injected almost simultaneously from the fuel gas injector 8 and the fuel oil injector 10, In the combustion chamber c under a high temperature atmosphere, the fuel oil 10a having a good compression ignitability self-ignites, whereby the fuel gas 10a injected almost simultaneously burns, and as shown in FIG. In this way, a combustion flame f is generated.

  That is, the ECU 12 constitutes the fuel gas injection timing control means in the present invention, and the ignition timing control according to the present invention ignites the fuel gas in the combustion chamber c by the fuel injection device 10 when the piston 4 is located near the top dead center. Means. In the present invention, the vicinity of the top dead center means a state where the piston 4 is located in a range from 10 ° before top dead center to 20 ° after top dead center.

<First Embodiment>
Next, a two-cycle engine according to a first embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a schematic diagram for explaining the two-cycle gas engine according to the first embodiment of the present invention. FIG. 3A shows the piston 4 positioned 10 ° to 100 ° before top dead center. The state, (b) shows the state where the piston 4 is located approximately 5 ° before the top dead center, and (c) shows the state where the piston 4 is located at the top dead center.

  In the two-cycle gas engine 1 of the present embodiment, when the piston 4 is in the upward stroke and the piston 4 is positioned 10 ° to 100 ° before top dead center (the state shown in FIG. 3A), Based on the signal transmitted from the ECU 12 (fuel gas injection timing control means) described above, the fuel gas 8b is injected from the fuel gas injection device 8 into the combustion chamber c. Thus, when the fuel gas 8b is injected into the combustion chamber c when the piston 4 is positioned 10 ° to 100 ° before top dead center, the piston 4 is injected in the process of further rising to near the top dead center. Further, the fuel gas 8b and the air inside the combustion chamber c are mixed to promote premixing. Then, as shown in FIG. 3B, the air-fuel mixture 20 is generated inside the combustion chamber c.

  Based on the signal transmitted from the ECU 12 (fuel gas injection timing control means and ignition timing control means) described above when the piston 4 reaches near the top dead center (for example, about 5 ° before the top dead center), the fuel is The fuel gas 8a is injected from the gas injection device 8, and the fuel oil 10a is injected from the fuel oil injection device 10.

  Then, as described above, the fuel oil 10a having good compression ignitability self-ignites, and the injected fuel gas 8a is also combusted. And as shown in FIG.3 (c), the combustion flame f is produced | generated inside the combustion chamber c. And this combustion flame f propagates to the air-fuel mixture 20 described above, and explosive combustion occurs in the entire combustion chamber c.

  As described above, the two-cycle gas engine 1 of the present embodiment injects the fuel gas 8b when the piston 4 is positioned 10 ° to 100 ° before the top dead center, and further when the piston 4 is positioned near the top dead center. The fuel gas 8a and the fuel oil 10a are injected. Therefore, the premixing of the fuel gas 8b and the air injected when the piston 4 is located 10 ° to 100 ° before top dead center is promoted to generate the air-fuel mixture 20, thereby generating one of the combustion modes. The part is premixed combustion. For this reason, generation | occurrence | production of NOx (nitrogen oxide) can be suppressed compared with the conventional gas engine in which all the combustion forms are diffusion combustion.

  The two-cycle gas engine 1 of the present embodiment is configured only by controlling the injection timing of the fuel gas injection device 8 by the fuel gas injection timing control means configured by the ECU 12. Therefore, it is possible to easily promote premixing in an existing two-cycle gas engine without requiring a new additional device or the like.

<Second Embodiment>
Next, a two-cycle engine according to a second embodiment of the present invention will be described with reference to FIG.
FIG. 4 is a schematic view for explaining a two-cycle gas engine according to a second embodiment of the present invention, in which (a) shows the piston 4 positioned 10 ° to 100 ° before top dead center. The state, (b) shows the state where the piston 4 is located approximately 5 ° before the top dead center, and (c) shows the state where the piston 4 is located at the top dead center.

  The two-cycle gas engine 1 of the present embodiment differs from the above-described embodiments in that the fuel gas injection means includes a first fuel gas injection means (first fuel gas injection device 8A) and a second fuel gas injection means (second fuel gas injection means). The fuel gas injection device 8B) is configured separately. For example, the same number of first fuel gas injection devices 8A are arranged at the same position and in the same direction as the fuel gas injection device 8 in the above-described embodiment. On the other hand, as shown in FIG. 4, the second fuel gas injection device 8B is 180 in the circumferential direction with the cylinder center o as the rotation center at a middle position between the two first fuel gas injection devices 8A and 8A. Two are formed at positions apart from each other. Further, it is assumed that the first fuel gas injection device 8A and the second fuel gas injection device 8B are connected to the ECU 12 (fuel gas injection timing control means) described above.

  Then, as shown in FIG. 4A, the second fuel gas injection is performed when the piston 4 is positioned 10 ° to 100 ° before top dead center during the upward stroke based on the signal transmitted from the ECU 12. The fuel gas 8b is injected from the device 8B toward the combustion chamber c. As shown in FIG. 4B, the piston 4 reaches near the top dead center (for example, about 5 ° before the top dead center) based on a signal transmitted from the ECU 12 (fuel gas injection timing control means). At that time, the fuel gas 8a is injected from the first fuel gas injection device 8A toward the combustion chamber c. Further, as in the above-described embodiment, based on the signal transmitted from the ECU 12 (ignition timing control means), the fuel oil 10a is injected from the fuel oil injection device 10 almost simultaneously with the injection of the fuel gas 8a. It is like that.

  Thus, the fuel gas injection means of the present invention is configured separately for the first fuel gas injection means (first fuel gas injection device 8A) and the second fuel gas injection means (second fuel gas injection device 8B). If so, the injection direction of the fuel gas can be made different between the first fuel gas injection device 8A and the second fuel gas injection device 8B. Therefore, as shown in FIG. 4, the injection direction of the fuel gas 8b injected from the second fuel gas injection device 8B is lower than the injection direction of the fuel gas 8a injected from the first fuel gas injection device 8A. The fuel gas 8b can be agitated inside the combustion chamber c and the premixing of the fuel gas 8b can be promoted. Further, when the piston 4 is positioned 10 ° to 100 ° before top dead center, the pressure inside the combustion chamber c is lower than when the piston 4 is near top dead center. For this reason, as the second fuel gas injection device 8B, an appropriate injection device that matches the operating pressure, which is different from the first fuel gas injection device 8A, can be adopted.

  As described above, according to the two-cycle gas engine 1 of the present invention, when the piston 4 is in the upward stroke and the piston 4 is positioned 10 ° to 100 ° before top dead center, the fuel gas injection means (fuel gas injection device 8 Alternatively, by injecting the fuel gas 8b from the second fuel gas injection device 8B), the premixing of the fuel gas 8b and air is promoted, and the ratio of diffusion combustion in the entire combustion is reduced, so that NOx ( It is possible to provide a two-cycle gas engine in which generation of nitrogen oxides) is suppressed.

  As mentioned above, although the preferable form of this invention was demonstrated, this invention is not limited to said form, A various change in the range which does not deviate from the objective of this invention is possible.

  For example, in the above-described embodiment, the ignition means is configured by the fuel oil injection device 10. And as mentioned above, based on the signal transmitted from ECU12 (ignition timing control means), the fuel oil 10a with high compression ignitability is injected from the fuel oil injection device 10 into the combustion chamber c in a high temperature atmosphere. The fuel gas in the combustion chamber c is ignited. However, the ignition means of the present invention is not limited to this. For example, the ignition plug provided in the cylinder head 3 is used as the ignition means, and the ignition plug is activated based on a signal transmitted from the ECU 12 (ignition timing control means). The fuel gas in the combustion chamber c may be ignited by the spark generated by the spark plug.

  The two-cycle gas engine of the present invention can be suitably used as a marine engine, particularly for construction machinery, large vehicles, and power generation.

1 2-cycle gas engine,
2 cylinder 2a peripheral wall 3 cylinder head 4 piston 4a top surface 5 piston ring 6 scavenging port 7 exhaust valve 8 fuel gas injection device (fuel gas injection means)
8A First fuel gas injection device (first fuel gas injection means)
8B Second fuel gas injection device (second fuel gas injection means)
8a Fuel gas 10 Fuel oil injection device 10a Fuel oil 12 ECU (fuel gas injection timing control means and ignition timing control means)
14, 16 Cable 15 Crank angle sensor 17 Crankshaft 20 Air-fuel mixture

Claims (4)

A cylinder and a cylinder head;
A piston housed in the cylinder and defining a combustion chamber between a peripheral wall of the cylinder and the cylinder head;
Fuel gas injection means provided in the cylinder head and for injecting fuel gas into the combustion chamber;
A scavenging port that opens in the peripheral wall of the cylinder and supplies air into the combustion chamber when the piston is positioned near bottom dead center;
The fuel gas is injected by the fuel gas injection means when the piston is in the ascending stroke and the piston is positioned near the top dead center, and the fuel gas injection is performed when the piston is positioned near the top dead center. Fuel gas injection timing control means configured to inject fuel gas by means;
With
The fuel gas injection means;
A first fuel gas injection device that injects fuel gas into the combustion chamber when the piston is located near top dead center;
A second fuel gas injection device configured to inject fuel gas into the combustion chamber when the piston is positioned in front of near the top dead center, configured separately from the first fuel gas injection device,
The two-cycle gas engine, wherein the second fuel gas injection device is configured to inject fuel gas into the combustion chamber at an injection pressure lower than that of the first fuel gas injection device. A cylinder and a cylinder head;
A piston housed in the cylinder and defining a combustion chamber between a peripheral wall of the cylinder and the cylinder head;
Fuel gas injection means provided in the cylinder head and for injecting fuel gas into the combustion chamber;
A scavenging port that opens in the peripheral wall of the cylinder and supplies air into the combustion chamber when the piston is positioned near bottom dead center;
A control device configured to control the fuel gas injection means;
With
The controller is
The fuel gas is injected by the fuel gas injection means when the piston is in the ascending stroke and the piston is positioned near the top dead center, and the fuel gas injection is performed when the piston is positioned near the top dead center. Configured to inject fuel gas by means,
The fuel gas injection means;
A first fuel gas injection device that injects fuel gas into the combustion chamber when the piston is located near top dead center;
A second fuel gas injection device configured to inject fuel gas into the combustion chamber when the piston is positioned in front of near the top dead center, configured separately from the first fuel gas injection device,
The two-cycle gas engine, wherein the second fuel gas injection device is configured to inject fuel gas into the combustion chamber at an injection pressure lower than that of the first fuel gas injection device. An exhaust valve provided at the top of the cylinder head for opening and closing an exhaust port;
The first fuel gas injection device is provided around the exhaust valve in the cylinder head,
The second fuel gas injection device is provided around the exhaust valve in the cylinder head,
The angle formed by the injection direction of the fuel gas injected from the second fuel gas injection device and the direction orthogonal to the advance / retreat direction of the piston is the injection direction of the fuel gas injected from the first fuel gas injection device 3. The two-cycle gas engine according to claim 1, wherein the two-cycle gas engine is configured to be larger than an angle formed by a direction perpendicular to the advancing and retreating direction of the piston. The first fuel gas injection device configured to inject fuel gas into the combustion chamber, and the combustion at an injection pressure lower than that of the first fuel gas injection device configured separately from the first fuel gas injection device A fuel gas injection means having a second fuel gas injection device configured to inject fuel gas into the chamber;
When the piston is in the ascending stroke and the piston is positioned near the top dead center, fuel gas is injected by the second fuel gas injection device, and when the piston is positioned near the top dead center, the first A control device configured to inject fuel gas by the fuel gas injection device;
A fuel gas injection system for a two-cycle gas engine.

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