JPH0674047A - Auxiliary chamber-type gas engine - Google Patents

Abstract

PURPOSE:To provide an auxiliary chamber-type gas engine for which a gas fuel whose makes compression ratio is made large, while whose self ignition is prevented, is used as its proper fuel. CONSTITUTION:An auxiliary chamber-type gas engine is provided with a connecting hole 30 for communicating an auxiliary chamber 2 with a main chamber 1, a separation valve 5 which opens/closes the connecting hole 30 and a fuel feed valve 4 which is arranged in the fuel entrance 13 of the auxiliary chamber 2, to be opened for supplying gas fuel to the auxiliary chamber 2. In a suction stroke, the separation valve 5 is closed to supply intake air to the main chamber 1 and the fuel feed valve 4 is opened to supply gas fuel to the auxiliary chamber 2. Next, the separation valve 5 is opened to supply compression air to the auxiliary chamber 2 at about the end of a compression stroke and air and gas fuel are mixed together to be burnt. Since intake air and gas fuel are not mixed together during a compression stroke self ignition is not generated so that generation of knocking may be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a separation valve for separating a main chamber and a sub-chamber from which a natural gas gas fuel is supplied to the sub-chamber and intake air is supplied to the main chamber to obtain a high compression ratio. It relates to a sub-chamber gas engine that secures

[0002]

2. Description of the Related Art Conventionally, an engine using natural gas as a main fuel has been developed as a cogeneration engine. In this cogeneration engine, power is taken out as electric energy by a generator, and heat of exhaust gas energy is heated by a heat exchanger to make hot water, which is used for hot water supply. Then, this cogeneration engine is expected to be used as an urban electricity supply system.

An engine using natural gas as fuel is disclosed in, for example, Japanese Patent Laid-Open No. 1-232119, Japanese Utility Model No. 3
There is one disclosed in Japanese Patent Publication No. 41068. The engine for hydrogen / liquefied natural gas disclosed in JP-A-1-232119 supplies either one of hydrogen as a fuel and liquefied natural gas in a low load operation state of the engine, and operates the engine under high load. In the state, a control means for supplying liquefied natural gas as a fuel is provided.

Further, the gas-fueled diesel engine disclosed in Japanese Utility Model Publication No. 3-41068 has a dual fuel in which a liquid fuel injection valve for injecting liquid fuel and a gas fuel injection valve for injecting gas fuel are provided in a cylinder cover. It is an injection type, and a gas fuel injection valve and a liquefied fuel gas tank in which gas fuel is stored are connected by two gas passages, a high pressure gas passage and a low pressure gas passage, and gas fuel is provided in each of the gas passages. A high-pressure compressor and a low-pressure compressor that pressurize the gas to different pressures and supply it to the gas fuel injection valve are respectively provided. And a low-pressure gas injection port for injecting the low-pressure gas.

Further, Japanese Patent Laid-Open No. 3-279667 discloses a fuel injection nozzle for a combustion chamber variable engine. The fuel injection nozzle of the combustion chamber variable engine has a valve that opens and closes the opening of the auxiliary combustion chamber, and opens and closes the opening according to at least the engine load. The valve when the opening is in the open state A nozzle tip portion disposed at a position facing the shaft portion of the valve, and at least two nozzle holes formed in the nozzle tip portion for injecting fuel at a symmetrical position with respect to the valve shaft portion. There is.

[0006]

Conventionally, a gas engine operates in a sabate cycle. Generally, the working gas of an engine such as a high-speed diesel engine undergoes a state change similar to that of a sabate cycle. The Sabate cycle is a combustion that is performed in two states of equal volume and equal pressure. If the area of constant pressure heat reception approaches zero, it becomes an otto cycle, and if the area of constant volume heat dissipation approaches zero and equal pressure is reached. If there is no heat received, the diesel cycle will start. The gas engine is operated in a suction stroke, a compression stroke, a spark ignition by mixing air and a gas fuel, and an expansion stroke and an exhaust stroke.

However, in a gas engine using natural gas as a fuel, since the fuel is a gas body, knocking occurs, so that the compression ratio cannot be increased and the compression ratio is limited to about 11 to 12. Therefore, theoretical thermal efficiency is not necessarily high. Therefore, when the gas engine is powered by electric energy, the thermal efficiency is low, which is not preferable. In some sub-chamber engines, gas is drawn into the sub-chamber and lean burn combustion is performed to improve thermal efficiency. However, even such a sub-chamber engine has a compression ratio of about 13, which is significantly different from a diesel engine having a compression ratio of 18 or more. Considering theoretical thermal efficiency, a method with a high compression ratio is advantageous,
In an engine with a displacement of 2 liters per cylinder, a compression ratio of about 15 to 16 is optimal, but if the compression ratio is increased, the gas fuel self-ignites and causes knocking. The current situation is that the compression ratio cannot be achieved.

Therefore, in the present situation, it is desired to improve the thermal efficiency when the electric energy is taken out from the gas engine. By the way, the gas engine
It uses natural gas as fuel, and the fuel is gas. Therefore, when the gas is sucked in the suction stroke and then compressed, the compression becomes high and the temperature rises, and the phenomenon of self-ignition, that is, knocking occurs. However, the gas fuel of natural gas will self-ignite unless the compression ratio is 12 or less. Regarding the thermal efficiency of the engine, there is a phenomenon that the thermal efficiency decreases when the compression ratio is small. Therefore, in gas engines, avoid self-ignition of gas fuel,
There is a problem of how to increase the compression ratio.

Therefore, an object of the present invention is to solve the above-mentioned problems, and a separation valve for separating the main chamber and the sub chamber is provided in the communication hole, and a gas fuel of natural gas is introduced into the sub chamber, Only the intake air is compressed in the main chamber to increase the compression ratio, and while the air in the main chamber is raised to a high temperature, the communication hole valve of the communication hole is opened to allow the highly compressed air in the main chamber to flow into the sub chamber. ,
By mixing the gas fuel and highly compressed air in the sub-chamber at once, they are ignited and burned in a short period of time. Moreover, since the fuel is rich in the sub-chamber, they are burned in a state where the generation of NO _X is suppressed,
By blowing out the flame from the sub-chamber to the main chamber at once, the secondary combustion is completed with a mixture as homogeneous as possible in a short time.
It is an object of the present invention to provide a sub-chamber gas engine using natural gas as a fuel, which can reduce the generation of _X , HC, etc., particularly improve thermal efficiency, prevent self-ignition of gas fuel, and prevent knocking. .

[0010]

In order to achieve the above object, the present invention is configured as follows. That is,
According to the present invention, a sub-chamber wall body forming a sub-chamber arranged in a mounting hole of a cylinder head, a main chamber formed on a cylinder side, a communication hole communicating the sub-chamber with the main chamber, and opening and closing the communication hole. A separation valve, a fuel supply valve arranged at a fuel inlet of the sub chamber which is opened to supply a gas fuel to the sub chamber, a separation valve which is closed in an intake stroke to supply intake air to the main chamber and the fuel A supply valve is opened to supply gas fuel to the sub chamber; and a separation valve is opened near the end of the compression stroke to supply compressed air to the sub chamber to mix and burn the gas fuel. The present invention relates to a sub-chamber gas engine characterized by the above.

In this sub-chamber gas engine,
The separation valve is slid in the communication hole in the longitudinal direction to variably control the sub-chamber volume so that the sub-chamber volume becomes maximum at the suction stroke end and decreases from the compression stroke start end to the compression stroke end. Is.

Further, in this sub-chamber gas engine,
The sub chamber block forming the sub chamber and the communication hole and the separation valve are made of ceramics such as silicon nitride having a small thermal expansion coefficient and high heat resistance.

Alternatively, in this sub-chamber type gas engine, the separation valve comprises a tubular portion rotatably arranged in the sub-chamber and a valve stem integral with the tubular portion, and the hole formed in the tubular portion is By aligning with the communication hole, the sub chamber and the main chamber are in communication with each other.

Furthermore, in this sub-chamber gas engine,
The open passage area between the hole and the communication hole is variably controlled by controlling the rotation angle of the separation valve to control the alignment state of the hole and the communication hole.

[0015]

The sub-chamber type gas engine according to the present invention is constructed as described above and operates as follows. That is, in this sub-chamber type gas engine, the communication state of the communication hole that communicates the main chamber and the sub chamber is controlled by a separation valve, and a gas supply valve is arranged at the fuel inlet formed in the sub chamber to supply natural gas to the fuel. Supply to the sub chamber through a passage, close the separation valve in the intake stroke to supply intake air to the main chamber, and open the gas supply valve to supply natural gas to the sub chamber, compression stroke Near the end, the separation valve is opened to supply compressed air from the main chamber to the sub chamber for combustion, so that even if the intake air has a high compression ratio in the main chamber, the gas fuel supplied to the sub chamber Since the air is not mixed, the gas fuel does not self-ignite and knocking does not occur. Therefore, the engine can be operated at a high compression ratio and the thermal efficiency can be improved.

Further, by opening the communication hole with the separation valve, highly compressed intake air flows into the sub chamber from the main chamber, gas fuel and intake air are mixed and ignited, and an equivalence ratio is obtained. generation of the NO _X is suppressed at high speed with a large fuel-rich combustion.

Further, the separation valve is slid in the communication hole in the longitudinal direction so that the sub-chamber volume becomes the maximum volume at the end of the suction stroke, and the sub-chamber volume becomes smaller from the compression stroke start end to the compression stroke end. Since it is variably controlled, the volume of the sub chamber can be variably controlled, and a high compression ratio can be achieved. Moreover, since the volume of the sub chamber is variable, the volume ratio of the sub chamber can be increased, and mixing of the compressed gas fuel and the compressed air in the sub chamber can be promoted. In addition, since the sub chamber is also compressed during the compression stroke as the intake air is compressed,
The theoretical thermal efficiency (η = heat conversion of work / heat quantity of fuel) does not decrease.

Further, in this sub-chamber gas engine,
Since the sub chamber block forming the sub chamber and the communication hole and the separation valve are made of ceramics such as silicon nitride having a small thermal expansion coefficient and high heat resistance, the separation valve slides in the communication hole. Even if the temperature becomes high in, the gap between the separation valve and the communication hole can be kept to a minimum without being affected by the temperature change.

Alternatively, in this sub-chamber type gas engine, the separation valve is constituted by a tubular portion configured to be rotatable in the sub-chamber and a valve stem integral with the tubular portion, and a hole formed in the tubular portion is formed. Since the sub chamber and the main chamber are in communication with each other by matching the communication hole, the gas engine can have a high compression ratio. Further, the opening passage area between the hole and the communication hole can be variably controlled by controlling the rotation angle of the separation valve, and the amount of intake air supplied to the sub chamber can be changed according to the operating state of the engine. Can be controlled.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sub-chamber gas engine according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a sub-chamber gas engine according to the present invention, and FIG. 2 is a cross-sectional view showing a moving state of a separation valve in the sub-chamber gas engine of FIG. As shown in the figure, this sub-chamber type gas engine includes a cylinder block 14 forming a cylinder 18, a cylinder head 7 fixed to the cylinder block 14 via a gasket, and an intake / exhaust port 25 formed in the cylinder head 7 (only one side). Intake / exhaust valve 20 (only one shown) disposed in intake / exhaust port 25,
A sub chamber 2 formed by a sub chamber wall 3 arranged in a mounting hole 19 formed in the cylinder head 7, a piston 15 reciprocating in the cylinder 18, a main chamber 1 formed on the cylinder 18 side,
Also, it has a communication hole 30 formed in the sub-chamber wall body 3 that connects the main chamber 1 and the sub-chamber 2 to each other.

This sub-chamber type gas engine has, in particular, a separation valve 5 for opening and closing the communication hole 30, and a gas supply valve 4 arranged at a fuel inlet 13 of the sub-chamber 2 which is opened for supplying gas fuel to the sub-chamber 2. have. The communication hole 30 is formed in a cylindrical shape, and the sub chamber 2 is formed with a diameter larger than the inner diameter of the communication hole 30. The outer diameter of the separation valve 5 is slightly smaller than the inner diameter of the communication hole 30, and the separation valve 5 is fitted in the communication hole 30 so as to be slidable in the longitudinal direction. Isolation valve 5
Is moved up and down via the rocker arm 12 according to the rotational movement of the cam 9. The separation valve 5 has a communication hole 30 shown in FIG.
At the lower end 33, that is, at the end of the suction stroke, the volume of the sub-chamber 2 becomes the largest, and the separation valve 5 moves up the communication hole 30 by the spring force of the spring 24 from the start end of the compression stroke to the end of the compression stroke. When the face 31 of the separation valve 5 separates from the upper end 32 of the communication hole 30 and further rises, the separation function of the separation valve 5 is lost, and the main chamber 1 and the sub chamber 2 are separated from each other. Are communicated with each other through the communication hole 30.

This sub-chamber gas engine uses a natural gas fuel, and although not shown, the fuel gas is stored in a fuel tank and the natural gas from the fuel tank is stored in a pressure accumulator. It is accumulating pressure. Natural gas in the accumulator can be supplied to the sub chamber 2 from the fuel inlet 13 of the sub chamber 2 through the fuel passage 6 provided with the flow rate adjusting valve. At the fuel inlet 13, a fuel supply valve 4 that opens and closes the fuel inlet 13 by operating the cam 8 is arranged. Further, the intake / exhaust valve 20 arranged in the intake / exhaust port 25
Is opened / closed by the cam 11 or the like as in the case of a general 4-cycle operation.

Further, the separation valve 5 is slid in the communication hole 30 in the longitudinal direction to variably control the sub-chamber volume so as to have the maximum volume at the end of the suction stroke. Sub chamber 2 and communication hole 3
The sub chamber wall body 3 and the separation valve 5 forming 0 are made of ceramics such as silicon nitride and silicon carbide having a small thermal expansion coefficient and high temperature strength and high heat resistance. By making the sub chamber wall body 3 and the separation valve 5 from the above materials, the gap itself can be made small, and the gap between the separation valve 5 and the communication hole 30 can be deformed due to the difference in thermal expansion even at high temperature. Instead, the separation valve 5 can always be maintained at a constant gap, and the separation valve 5 can slide smoothly.

The operation of this sub-chamber gas engine will be described with reference to FIG. FIG. 3 is a diagram showing the valve timing when the sub-chamber gas engine is operated with four strokes. This sub-chamber gas engine is a four-cycle engine that is operated by sequentially repeating four strokes of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.
Particularly, in the intake stroke, the separation valve 5 is closed to supply the intake air to the main chamber 1, the gas supply valve 4 is opened to supply the gas fuel to the sub chamber 2, and then the separation is performed near the end of the compression stroke. The valve 5 is opened and compressed air is supplied to the sub chamber 2 to mix the gas fuel and ignite and burn.

In the intake stroke, the intake valve 20 is connected to the intake port 2
5 is opened to supply the intake air to the main chamber 1, and the separation valve 5 closes the communication hole 30 to open the fuel supply valve 4 to open the fuel passage 6 from the pressure accumulating chamber to the sub chamber 2 as a natural gas. Fuel is supplied. At this time, the separation valve 5 descends as the suction stroke progresses, the sub-chamber volume rises, and the volume of the sub-chamber 2 becomes maximum at the end of the suction stroke.

Next, the piston 15 rises and shifts to the compression stroke, and the separation valve 5 rises from the lower end 33 of the communication hole 30 as the compression stroke progresses. The pressure in the sub chamber 2 at the beginning of compression is controlled by a control valve provided in the fuel passage 6, and the internal pressure of the sub chamber 2 (for example, 3 to 5 kg /
cm ² ) is set higher than the internal pressure of the main chamber 1 (for example, 1 kg / cm ² ). Since the volume change of the sub chamber 2 due to the displacement of the separation valve 5 is smaller than the volume change of the main chamber 1, the pressure in the main chamber 1 is larger than that in the sub chamber 2. Therefore, in the compression stroke, the communication hole 30 is closed by the separation valve 5, and the intake air is highly compressed in the main chamber 1 to increase the compression ratio. Next, in the vicinity of the end of the compression stroke, the separation valve 5
Since the communication hole 30 is located at the upper end 32 of the communication hole 30, and the separation valve 5 is further raised, the separation function of the separation valve 5 is lost, and the main chamber 1 and the sub chamber 2 are communicated with each other through the communication hole 30. become. Therefore, the compressed air that has been highly compressed and has a high temperature (for example, 650 ° C.) flows into the sub chamber 2 from the main chamber 1 through the communication hole 30, and the intake air promotes mixing with the activated gas fuel and is ignited and burned. Combustion progresses rapidly and burns in a fuel rich state with NO _X reduced.

Next, the flame of the sub-chamber 2 gushes into the main chamber 1,
The process proceeds to the expansion stroke, promotes mixing with the fresh air existing in the main chamber 1 and completes secondary combustion in a short period of time. In this expansion stroke,
While maintaining the open state of the communication hole 30, a flame is ejected from the sub chamber 2 to the main chamber 1 to perform work, and the separation valve 5 descends near the end of the exhaust stroke to close the communication hole 30.

As described above, this sub-chamber type gas engine is provided with the communication hole 30 and the fuel inlet 13 in the sub-chamber 2, and the natural gas from the fuel tank in which the natural gas is stored is separated by the separation valve 5 into the communication hole 30. Fuel inlet 13 closed
From the intake port 25 to the main chamber 1
The intake air sucked into the main chamber 1 is compressed in the upward compression stroke of the piston 15 in a state where the communication hole 30 is closed by the separation valve 5 and the intake air is not supplied to the sub chamber 2. Even when highly compressed, the gas fuel supplied into the sub chamber 2 is isolated from the main chamber 1 by the separation valve 5, so that it does not self-ignite and knocking does not occur. Further, since the separation valve 5 opens the communication hole 30, the intake air having a high compression ratio flows from the main chamber 1 into the sub chamber 2, the fuel gas and the intake air are mixed and ignited, and the equivalence ratio is large. High-speed combustion is performed in a fuel-rich state, and the generation of NO _X is suppressed.

In this sub-chamber gas engine, knocking does not occur and the volume of the sub-chamber 2 is variable,
A high compression ratio can be achieved, and since the sub chamber is also compressed when the intake air is compressed, the theoretical thermal efficiency does not decrease. Moreover, since the volume of the sub-chamber 2 is variable, the volume ratio of the sub-chamber 2 can be made large, and by making the volume ratio of the sub-chamber 2 large, gas fuel and air in the sub-chamber 2 Can be promoted.

On the other hand, when the main chamber and the sub chamber are completely separated and the sub chamber is not a variable structure, in order to secure a compression ratio of about 16 when the main chamber and the sub chamber are in communication, The compression ratio of the main chamber needs to be 22.4 (sub chamber ratio V / R = 30%). Moreover, the compression work at this time is wasted when the separation valve establishes communication between the main chamber and the sub chamber.
For example, in order to secure the total compression ratio 16 of the main chamber and the sub chamber, the sub chamber ratio V / R is 10% and the compression ratio of the main chamber is 17.
3, V / R ratio of the auxiliary chamber is 20% and compression ratio of the main chamber is 19.7
5, V / R ratio of the auxiliary chamber is 30% and compression ratio of the main chamber is 22.4
3, the sub-chamber ratio V / R is 40% and the compression ratio of the main chamber is 26.0.

Next, another embodiment of the sub-chamber gas engine according to the present invention will be described with reference to FIGS. 4 is a sectional view showing another embodiment of the sub-chamber gas engine according to the present invention, FIG. 5 is an explanatory view showing a sub-chamber, an intake / exhaust port and the like in the sub-chamber gas engine of FIG. 4, and FIG. It is explanatory drawing which shows the isolation valve in a chamber type gas engine. In each figure, the same parts as those in FIG. 1 are designated by the same reference numerals.

In this embodiment, the cylinder liner 36 forming the cylinder 18 is fitted in the hole formed in the cylinder block 14, and the main chamber 1 is fitted in the large-diameter mounting hole 19 formed in the cylinder head 7. Headliner 1 which is a wall
It is formed of zero. Headliner 10 is cylinder 1
8, a liner upper portion 28 and a head lower surface portion 29 that form a part of
It consists of On the upper surface of the head lower surface portion 29, the sub chamber wall body 3 that constitutes the sub chamber 2 is integrally formed.
The sub-chamber wall 3 is fitted in the small-diameter mounting hole 19 of the cylinder head 7. A valve seat 26 of the intake / exhaust valve 20 and a communication hole 30 are formed in the head lower surface portion 29.

Particularly, in this sub-chamber type gas engine,
The separation valve 16 includes a tubular portion 21 and a valve stem 22 that is integrally connected to the tubular portion 21 by a plurality of ribs 37. A gear 34 attached to the upper end of the valve stem 22 meshes with a gear 35 that rotates in synchronism with the engine. By transmitting the rotational force of the gear 35 to the valve stem 22 through the gear 34, the tubular portion 21 is subordinate. It will rotate in the chamber 2. The sub-chamber 2 and the main chamber 1 are communicated with each other by aligning the hole 23 formed in the tubular portion 21 with the communication hole 30 formed in the head liner 10. Then, by controlling the rotation angle of the separation valve 16 to control the matching state between the hole 23 and the communication hole 30, the open passage area between the hole 23 and the communication hole 30 can be variably controlled.

In this embodiment, the headliner 10 which is a wall forming the main chamber 1, the sub-chamber wall 3 forming the sub-chamber 2, and the separation valve 16 rotatable in the sub-chamber 2 are made of a low thermal expansion material. It is made of ceramics such as silicon nitride and silicon carbide, which are excellent in high temperature strength and heat resistance. Therefore, even if the gas temperature in the latter stage of combustion becomes high, it has sufficient heat resistance and high temperature strength, and improves the matching state between the holes 23 and the communication holes 30,
The communication state between the main chamber 1 and the sub chamber 2 can be accurately controlled, and no gap is generated due to the difference in thermal expansion. The volume ratio of the sub chamber 2 is 10% to 30% of the total volume of the compression end,
The compression ratio when the communication hole 30 is closed is 17.7 to 22.4.
3, the compression ratio is 16 when the communication hole 30 is open and the main chamber 1 and the sub chamber 2 are in communication. Further, the operation of the sub-chamber type gas engine of this embodiment is the same as that of the above embodiment except that the separation valve 16 is rotationally driven, and therefore the description thereof is omitted here.

[0035]

The sub-chamber gas engine according to the present invention is
It is configured as described above and has the following effects. That is, in this sub-chamber gas engine, the sub-chamber and the main chamber are communicated with each other by a communication hole, a separation valve is arranged in the communication hole to open and close the communication hole, and the fuel arranged at the fuel inlet of the sub-chamber is connected. The supply valve is opened to supply the gas fuel to the sub chamber, the separation valve is closed during the intake stroke to supply the intake air to the main chamber, and the fuel supply valve is opened to supply the gas fuel to the sub chamber. Then, the separation valve is opened near the end of the compression stroke to supply the compressed air to the sub chamber to mix and burn the gas fuel, so that the intake air can be highly compressed in the main chamber. Further, since the sub chamber is compressed and sealed in the absence of air and the volume of the sub chamber can be increased, the mass of the gas fuel supplied to the sub chamber can be increased and the gas fuel does not self-ignite. Further, even if the intake air has a high compression pressure in the main chamber, the sub-chamber is closed by the separation valve to shut off from the main chamber, and the pressurized gas fuel in the sub-chamber self-ignites. Without knocking.

When the separation valve is actuated and the communication hole is opened, the air highly compressed and heated to a high temperature from the main chamber flows into the sub chamber at once, and the gas fuel and the intake air are mixed. NO _X There was ignited at once accelerated, since the in auxiliary chamber is fast combusted in large fuel-rich equivalence ratio
Is suppressed. Then, the pressure in the sub-chamber suddenly rises due to combustion, which promotes combustion, and at the same time,
The flame is blown from the sub chamber to the main chamber all at once through the communication hole, and the flame is mixed with fresh air in the main chamber to promote premixed combustion and increase the combustion speed to achieve an ideal secondary combustion. Complete the combustion. Therefore, this subchamber gas engine
It is possible to greatly reduce the generation of NO _x , HC, etc., and provide a highly efficient engine.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a sub-chamber gas engine according to the present invention.

FIG. 2 is a cross-sectional view showing a state where a separation valve in the sub-chamber gas engine of FIG. 1 has moved.

FIG. 3 is a diagram showing a valve timing when this sub-chamber gas engine is operated with four strokes.

FIG. 4 is a sectional view showing another embodiment of the sub-chamber gas engine according to the present invention.

5 is an explanatory view showing a sub chamber, a separation valve, an intake / exhaust port and the like in the sub chamber type gas engine of FIG.

FIG. 6 is an explanatory diagram showing a separation valve in this sub chamber type gas engine.

[Explanation of symbols]

 1 Main Chamber 2 Sub Chamber 3 Sub Chamber Wall 4 Fuel Supply Valve 5, 16 Separation Valve 6 Fuel Passage 7 Cylinder Head 10 Headliner 13 Fuel Inlet 14 Cylinder Block 15 Piston 18 Cylinder 19 Mounting Hole 20 Intake / Exhaust Valve 21 Cylindrical Section 22 Valve stem 23 Hole 25 Intake / exhaust port 30 Communication hole 32 Upper end 33 Lower end

Claims (5)

[Claims] 1. A sub-chamber wall body forming a sub-chamber arranged in a mounting hole of a cylinder head, a main chamber formed on the cylinder side, a communication hole for communicating the sub-chamber with the main chamber, and opening / closing the communication hole. A separation valve, a fuel supply valve disposed at a fuel inlet of the sub chamber that is opened to supply gas fuel to the sub chamber, the separation valve is closed in an intake stroke to supply intake air to the main chamber, and Opening a fuel supply valve to supply gas fuel to the sub-chamber; and opening the separation valve near the end of the compression stroke to supply compressed air to the sub-chamber to mix and burn the gas fuel. A sub-chamber gas engine characterized by being constructed. 2. The separation valve is slid longitudinally in the communication hole to maximize the volume of the sub chamber at the end of the suction stroke, and the volume of the sub chamber decreases from the start of the compression stroke to the end of the compression stroke. The subchamber gas engine according to claim 1, wherein the subchamber gas engine is variably controlled. 3. The sub-chamber wall forming the sub-chamber and the communication hole and the separation valve are made of ceramics such as silicon nitride having a small thermal expansion coefficient and high heat resistance. The sub-chamber gas engine according to 2. 4. The separation valve comprises a tubular portion that is configured to be rotatable in the sub chamber and a valve stem that is integral with the tubular portion, and the hole formed in the tubular portion is aligned with the communication hole, so that The sub-chamber gas engine according to claim 1, wherein the sub-chamber and the main chamber are in communication with each other. 5. An open passage area between the hole and the communication hole is variably controlled by controlling a rotation angle of the separation valve to control a matching state between the hole and the communication hole. The sub-chamber gas engine according to claim 4.