JPH10266880A - Fuel supplying device of divided torch ignition type gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the sure ignition and combustion in a subsidiary-combustion chamber by detecting the fuel gas concentration or oxygen concentration within the subsidiary-combustion chamber, calculating the fuel gas concentration on the basis of the detected concentration, and controlling the pressure of the torch ignition fuel gas to the subsidiary-combustion chamber on the basis of the calculated result. SOLUTION: In the operation of a torch ignition type gas engine, air-fuel mixture is introduced into a main combustion chamber 10 through an intake valve, and torch igniting gas is also introduced into a gas chamber 6a through a gas passage 6b, and carried into a subsidiary-combustion chamber 11 when a subsidiary-chamber valve 5 is opened. At this time, a laser beam is transmitted from an YAG laser 13, and a laser beam regulated to a proper wavelength is made incident on the subsidiary- combustion chamber 11 from the probe 17. An electric signal according to luminous intensity is transmitted from a light detecting device 21 for receiving the scattered light passed through an optical filter 20 to a controller 1, wherein it is converted into fuel gas concentration, and compared with a set fuel gas concentration range, and a gas pressure control device 3 is controlled by the gas pressure regulating quantity according to this difference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sub-combustion type in which a torch ignition fuel gas is ignited by a spark plug in a sub-combustion chamber, and the ignition gas is jetted into a main combustion chamber to burn a mixture in the main combustion chamber. The present invention relates to a gas fuel supply device for a chamber torch ignition type gas engine.

[0002]

2. Description of the Related Art FIG. 5 shows a cross section around a combustion chamber of a conventional sub-chamber torch ignition type gas engine and a fuel supply system. FIG.
In the figure, reference numeral 8 denotes a cylinder head, and 10 denotes a main combustion chamber, which is defined by an upper surface of a piston (not shown), an inner surface of a cylinder (not shown), and a lower surface of the cylinder head 8. A mixture of fuel and air is introduced into the main combustion chamber 10 via an intake valve (not shown).

[0003] Reference numeral 11 denotes a sub-combustion chamber, which is provided substantially in the center of the cylinder head 8 in the cylinder axis direction. A sub-chamber upper metal part 6 is provided at an upper part of the sub-combustion chamber 11, and a sub-chamber base 9 is provided at a lower part thereof. Reference numeral 6a denotes a gas chamber formed in the metal fitting 6 above the sub-chamber, and the gas chamber 6a is connected to the gas supply pipe 4 via a gas passage 6b.

[0004] Reference numeral 5 denotes a sub-chamber valve slidably fitted in the sub-chamber upper metal part 6.
Open and close between 1 The sub chamber base 9 is provided with a small-diameter injection port 11a. Reference numeral 7 denotes an ignition plug for igniting the fuel gas in the auxiliary combustion chamber 11.

[0005] Reference numeral 3 denotes a gas pressure control device provided in the gas supply pipe 4, and reference numeral 1 denotes a controller that sends a control signal to the gas pressure control device 3 via the control line 2.

[0006] During the operation of such a conventional gas engine,
The fuel gas for torch ignition passes through the gas supply pipe 4 and is adjusted to a set pressure by the gas pressure control device 3 and then to the gas chamber 6a through the gas passage 6b in the metal fitting 6 above the sub-chamber. enter. The torch ignition fuel gas flows into the sub-combustion chamber 11 when the sub-chamber valve 5 is opened by an opening / closing signal from a valve opening / closing control device (not shown) based on rotation of a crankshaft (not shown).

The main combustion chamber 10 has a high efficiency,
In order to realize low-pollution combustion, a mixture of fuel and air in a fuel-lean state is sucked through an intake valve (not shown).

When a high voltage is applied to the ignition plug 7 by an ignition device (not shown) linked to the rotation of the engine, the torch ignition fuel gas in the sub-combustion chamber 11 is ignited by spark discharge from the ignition plug 7. Burned. The ignited fuel gas is ejected from the injection port 11a into the main combustion chamber 10 to burn the lean mixture in the main combustion chamber 10.

[0009]

In such a sub-chamber torch ignition type gas engine, the concentration of the torch ignition fuel gas introduced into the sub-combustion chamber 11 is within a concentration range suitable for ignition and combustion. The torch ignition fuel gas ignited in the sub combustion chamber 11 is injected into the main combustion chamber 10 to completely burn the lean air-fuel mixture in the main combustion chamber 10, and is indispensable in such a concentration range. In such a case, the discharge of unburned fuel may cause the engine to stop.

However, the concentration of the torch ignition fuel gas in the sub-combustion chamber 11 as described above can be controlled by the pressure of the fuel gas supplied to the sub-combustion chamber 11. In the gas engine according to the prior art shown in FIG. 5, the pressure of the torch ignition fuel gas is controlled to be equal to the pressure set in the gas pressure control device 3.

However, the relationship between the set gas pressure and the concentration of the fuel gas in the sub-combustion chamber 11 changes depending on the operating conditions of the engine, the temperature of the intake air, and the like. It is extremely difficult to maintain.

In view of the above-mentioned problems of the prior art, the present invention controls the gas pressure of the torch ignition fuel gas supplied to the sub-combustion chamber with high accuracy so that the fuel gas in the sub-combustion chamber is allowed under any operating conditions. It is a first object of the present invention to provide a torch-ignition type gas engine in which ignition and combustion are reliably performed while maintaining the concentration of the gas within an optimum range.

It is a second object of the present invention to provide a sub-chamber torch ignition type gas engine capable of controlling the fuel gas concentration with high responsiveness.

[0014]

According to the present invention, a fuel gas for igniting a torch is guided to a sub-combustion chamber provided in a cylinder head through a gas supply pipe, and the fuel gas is ignited by a spark plug. Then, in a sub-chamber torch ignition type gas engine configured to inject the fuel torch from an injection port into an air-fuel mixture in the main combustion chamber to burn the air-fuel mixture, the fuel gas concentration or the oxygen concentration in the sub-combustion chamber is A fuel gas concentration detected by the concentration detecting means, or a fuel gas for torch ignition to the sub-combustion chamber based on a fuel gas concentration calculated based on the detected oxygen concentration. A fuel supply device for a sub-chamber torch ignition type gas engine, comprising: gas pressure control means for controlling pressure.

Preferably, the present invention is configured such that the concentration detecting means includes a means for receiving a laser beam incident on the sub-combustion chamber and performing optical measurement.

According to this invention, the laser beam is incident on the fuel gas in the sub-combustion chamber, the laser beam is received, and an optical signal corresponding to the intensity, that is, the fuel gas concentration or the oxygen concentration is obtained. Converted to fuel gas concentration by controller,
The detected concentration is compared with the set appropriate fuel gas concentration to calculate a gas pressure adjustment amount corresponding to the concentration difference, and output this to the gas pressure control means. , The pressure of the torch ignition fuel gas is controlled to an appropriate pressure.

As described above, according to the invention, the fuel gas concentration in the sub-combustion chamber is directly detected by irradiating the laser beam into the sub-combustion chamber, or the oxygen gas concentration is detected and the fuel gas concentration is detected based on the detected oxygen gas concentration. Since the concentration is calculated and the pressure of the torch ignition fuel gas into the sub-combustion chamber 11 is controlled in accordance with this fuel gas concentration, the concentration of the torch ignition fuel gas in the sub-combustion chamber is constantly ignited and the optimum range of combustion is maintained. The ignition of the torch fuel gas can be properly controlled.
Combustion can reliably ignite the mixture in the main combustion chamber.

In addition, a non-contact optical measurement method with high temporal and spatial resolution can be applied to the detection of the fuel gas concentration in the sub-combustion chamber, and high-precision control can be realized.

Further, if the configuration is such that the oxygen concentration in the sub-combustion chamber is measured, the same measurement system can cope with a change in the type of fuel.

In the above invention, preferably, the concentration detecting means is configured to detect a fuel gas concentration or an oxygen concentration in the vicinity of the ignition plug in the sub-combustion chamber.

According to this structure, the laser beam is incident on the vicinity of the ignition plug in the sub-combustion chamber, and the fuel gas concentration in the vicinity of the ignition plug is detected and controlled. Become.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. It's just

FIG. 1 is a system configuration diagram of the vicinity of a combustion chamber and a fuel supply device of a sub-chamber torch ignition type engine according to an embodiment of the present invention. In FIG. 1, 8 is a cylinder head,
A main combustion chamber 10 is defined by an upper surface of a piston (not shown), an inner surface of a cylinder (not shown), and a lower surface of the cylinder head 8. A mixture of fuel and air is introduced into the main combustion chamber 10 via an intake valve (not shown).

Reference numeral 11 denotes a sub-combustion chamber, which is provided substantially in the center of the cylinder head 8 in the direction of the cylinder axis. A sub-chamber upper metal part 6 is provided at an upper part of the sub-combustion chamber 11, and a sub-chamber base 9 is provided at a lower part thereof. Reference numeral 6a denotes a gas chamber formed in the metal fitting 6 above the sub-chamber, and the gas chamber 6a is connected to the gas supply pipe 4 via a gas passage 6b.

Reference numeral 5 denotes a sub-chamber valve slidably fitted in the sub-chamber upper metal part 6, which opens and closes the gas chamber 6a and the sub-combustion chamber 11. The sub chamber base 9 is provided with a small-diameter injection port 11a. 7 is the auxiliary combustion chamber 11
It is a spark plug for igniting the fuel gas inside.

Reference numeral 3 denotes a gas pressure control device provided in the gas supply pipe 4, and reference numeral 1 denotes a controller which sends a control signal to the gas pressure control device 3 via the electric line 2 as described later. The above configuration is the same as that of the prior art shown in FIG.

Reference numeral 17 denotes a laser beam incident probe, which is attached to the cylinder head 8 and has a distal end opened near the ignition plug 7 in the sub-combustion chamber 11. Reference numeral 18 denotes a detection light receiving probe, which is mounted on a coaxial position of the cylinder head 8 facing the laser light incidence probe 17, and has a front end opening to the auxiliary combustion chamber 11.

Reference numeral 12 denotes a laser driving device to which a control signal is inputted from the controller 1 via a control line 31.
Reference numeral 13 denotes a YAG laser, 14 denotes a dye laser, and 15 denotes a wavelength converter. The laser light having passed through the wavelength converter 15 passes through an optical fiber 16 and reaches the laser light incident probe 17. From the auxiliary combustion chamber 11.

Reference numeral 19 denotes an optical fiber connected to the detection light receiving probe 18, reference numeral 20 denotes an optical filter, reference numeral 21 denotes a light detection device, and light generated in the sub-combustion chamber 11 is received by the detection light reception probe 18. , Through the optical fiber 19, to an optical filter 20, and further from the optical filter 20 to a photodetector 21. The light detection signal from the light detection device 21 is converted into an electric signal here, and is input to the controller 1 via an electric line 32.

During operation of the torch ignition type gas engine having such a configuration, a mixture of fuel and air is introduced into the main combustion chamber 10 together with opening of an intake valve (not shown). The gas for igniting the torch passes through the gas supply pipe, is adjusted in pressure by the gas pressure control device 3 by a method described later, and then enters the gas chamber 6a via the gas passage 6b in the metal fitting 6 above the sub-chamber. And this torch ignition gas is
When the sub-chamber valve 5 is opened by an opening / closing signal from a valve opening / closing control device (not shown) based on the rotation of a crankshaft (not shown), it flows into the sub-combustion chamber 11.

On the other hand, a control signal for transmitting a laser beam from the controller 1 is transmitted via the control line 31 to the laser driving device 12.
Is input to the YAG by the laser driving device 12.
Laser light is emitted from the laser 13. This laser light drives the dye laser 14, and a laser light of a certain wavelength is emitted from the dye laser 14 and enters the wavelength converter 15. The laser light adjusted to an appropriate wavelength by the wavelength converter 15 is sent to a laser light incident probe 17 through an optical fiber 16 and is incident on the sub-combustion chamber 11 from the laser light incident probe 17.

When the laser beam is incident on the sub-combustion chamber 11, the intensity of the fuel gas (methane in this embodiment) in the sub-combustion chamber 11, that is, the intensity corresponding to the concentration of the fuel gas in the vicinity of the ignition plug 7. It emits light of an appropriate wavelength. The scattered light is received by a detection light receiving probe 18 provided at a position facing the laser light incident probe 17, and enters an optical filter 20 through an optical fiber 19.

The optical filter 20 removes wavelength components other than light scattered by the fuel gas. The optical filter 2
The scattered light passing through 0 is incident on the light detection device 21, and the light detection device 21 outputs an electric signal corresponding to the intensity of the incident light to the controller 1.

FIG. 2 shows a control block in the controller 1. In FIG. 2, an electric signal corresponding to the intensity of light from the photodetector 21 is input to a fuel gas concentration calculator 51 of a controller 51 via a line 32. In the fuel gas concentration calculation unit 51, the input electric signal,
That is, a signal corresponding to the intensity of the scattered light by the fuel gas in the sub-combustion chamber 11 is converted into a corresponding fuel gas concentration and output to the gas concentration comparing unit 52. On the other hand, 53
Denotes an appropriate gas concentration setting section, in which an appropriate gas concentration range in the sub-combustion chamber 11 is set.

The gas concentration comparing section 52 compares the actual fuel gas concentration input from the fuel gas concentration calculating section 51 with the fuel gas concentration range set in the appropriate gas concentration setting section 53 and compares them. Then, the difference between the actual fuel gas concentration (hereinafter referred to as the detected concentration) and the set fuel gas concentration (hereinafter referred to as the set concentration) is detected, and the result is output to the gas pressure adjustment amount calculating unit 54.

The gas pressure adjustment amount calculation unit 54 calculates the gas pressure adjustment amount corresponding to the concentration difference between the detected concentration and the set concentration and outputs the gas pressure adjustment amount output unit 55. That is, in the case where the detected concentration is lower than the set concentration, the gas pressure adjustment amount calculation unit 54 obtains a gas pressure increase amount (gas pressure increase amount) corresponding to the concentration difference,
When the detected concentration is higher than the set concentration, the amount of decrease in gas pressure corresponding to the concentration difference is output to the gas pressure adjustment amount output unit 55.

The gas pressure adjustment amount output section 55 outputs to the gas pressure control device 3 an operation signal corresponding to the gas pressure increase or decrease calculated as described above. The gas pressure control device 3 changes the gas pressure of the gas supply pipe 4 by an amount corresponding to the above-mentioned adjustment amount.
The pressure of the torch gas into the interior is varied.

As a result, the concentration of the fuel gas in the vicinity of the ignition plug 7 in the sub-combustion chamber 11 is adjusted to an appropriate value. In this state, spark discharge is performed by the ignition plug 7 and the sub-combustion chamber 1
The fuel gas for ignition of the torch in 1 is ignited and burned. This fuel gas is supplied from the injection port 11a to the main combustion chamber 1
0, and burns the lean mixture in the main combustion chamber 10.

As described above, according to the present embodiment, the laser beam is incident on the vicinity of the ignition plug 7 in the sub-combustion chamber 11 and the scattered light of the fuel gas in the vicinity of the ignition plug 7 in the sub-combustion chamber 11 is emitted. Detecting, converting the intensity into an electric signal and inputting the electric signal to the controller 1, and in the controller 1, converting the electric signal corresponding to the intensity of the scattered light into a fuel gas concentration;
The detected concentration is compared with a set appropriate fuel gas concentration, that is, a set concentration, to calculate a gas pressure adjustment amount corresponding to the concentration difference, and to output the gas pressure adjustment amount to the gas pressure control device 3, whereby the auxiliary combustion chamber is set. The fuel gas pressure to 11 is controlled to an appropriate pressure.

That is, according to the present embodiment, the fuel gas concentration around the ignition plug 7 in the sub-combustion chamber 11 is detected by irradiating the laser beam near the ignition plug 7 in the sub-combustion chamber 11. Since the pressure of the torch fuel gas into the sub-combustion chamber 11 is controlled in accordance with the fuel gas concentration, the concentration of the torch ignition fuel gas in the vicinity of the ignition plug 7 in the sub-combustion chamber 11 is constantly ignited. Control can be performed with high responsiveness to the optimum range of combustion, and appropriate ignition and combustion of the torch fuel gas can realize reliable ignition of the air-fuel mixture in the main combustion chamber 10.

Further, since the laser beam is incident on the vicinity of the ignition plug 7 in the sub-combustion chamber 11 and the concentration of the fuel gas in the vicinity of the ignition plug 7 is detected and controlled, the control can be performed with high responsiveness. .

In addition, a non-contact optical measurement method having high temporal and spatial resolution can be applied to the detection of the fuel gas concentration in the sub-combustion chamber 11, and high-precision control can be realized.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, Y in the first embodiment shown in FIG.
A semiconductor laser 25 is provided in place of the AG laser 13, the dye laser, and the wavelength converter 15.

That is, in FIG. 3, reference numeral 25 denotes a semiconductor laser which generates a laser beam having a wavelength suitable for measuring the oxygen concentration.
Driven by a laser drive device 12 controlled by the controller 1, the laser light is sent to a laser light incidence probe 17 via an optical fiber 16. Other configurations are shown in FIG.
Is the same as the first embodiment shown in FIG.
Elements are indicated by the same reference numerals.

In the second embodiment shown in FIG. 3, a control signal for transmitting a laser beam from
When the laser beam is input to the laser driving device 12 via the laser driving device 12, the laser driving device 12 emits a laser beam having a wavelength suitable for measuring the oxygen concentration from the semiconductor laser 25. This laser light passes through the optical fiber 16 and is incident on the laser light incident probe 1.
The laser beam is sent to the sub-combustion chamber 11 from the laser beam incident probe 17.

When the laser beam is incident on the sub-combustion chamber 11, the laser beam is absorbed in accordance with the concentration of oxygen in the sub-combustion chamber 11, and the absorbed laser beam is transmitted to the laser beam input probe 17. The light is received by a detection light receiving probe 18 provided at a position facing the optical filter 19 and enters an optical filter 20 through an optical fiber 19. The optical filter 20 removes a component having a wavelength other than the incident laser light to remove the light from the optical detection device 2.
Enter 1 The light detection device 21 outputs an electric signal corresponding to the intensity of the incident light to the controller 1.

FIG. 4 shows a control block diagram of the controller 1. This control block is similar to the control block diagram of the first embodiment shown in FIG. 2 except that an oxygen concentration conversion unit 56 is added to the step before the fuel gas concentration calculation unit 51. It is.

That is, an electric signal corresponding to the intensity of light from the photodetector 21 is input to the oxygen concentration converter 56 of the controller 1 via the line 32. Oxygen concentration converter 56
In the method, the electric signal corresponding to the input light intensity is converted into an oxygen concentration and input to a fuel gas concentration calculating unit.

The fuel gas concentration calculator 51 calculates the fuel gas concentration corresponding to the converted oxygen concentration and inputs the calculated fuel gas concentration to the gas concentration comparator 52. The functions of the gas concentration comparison unit 52, the gas pressure adjustment amount calculation unit 54, and the gas pressure adjustment amount output unit 55 are the same as those in the first embodiment shown in FIG.

In this embodiment, the semiconductor laser 2
5 is incident on the sub-combustion chamber 11 to detect the oxygen concentration in the sub-combustion chamber 11, calculate the fuel gas concentration based on this, and calculate the fuel gas concentration in accordance with the fuel gas concentration. 11 to control the pressure of the torch fuel gas into
The detection of the oxygen concentration in the sub-combustion chamber 11 can be performed by an optical measurement method which has a high time and spatial resolution and is non-contactable in the same manner as in the first embodiment, and high-precision control can be realized.

Further, since the oxygen concentration in the sub-combustion chamber 11 is measured, the same measurement system can cope with a change in the type of fuel.

[0052]

As described above, according to the first and second aspects of the present invention, the laser gas is incident on the sub-combustion chamber to directly detect the fuel gas concentration in the sub-combustion chamber or to detect the oxygen concentration. The fuel gas concentration is calculated based on this, and the pressure of the torch ignition fuel gas into the sub-combustion chamber 11 is controlled in accordance with the fuel gas concentration. The concentration can always be controlled within the optimum range of ignition and combustion with high responsiveness, and appropriate ignition and combustion of the torch fuel gas can realize reliable ignition of the air-fuel mixture in the main combustion chamber.

Further, if the configuration is such that the oxygen concentration in the sub-combustion chamber is measured, the same measurement system can cope with a change in the type of fuel.

According to the third aspect of the present invention, the laser beam is incident on the vicinity of the ignition plug in the sub-combustion chamber, and the fuel gas concentration near the ignition plug is detected and controlled. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a periphery of a combustion chamber and a fuel supply device of a sub-chamber torch ignition type gas engine according to a first embodiment of the present invention.

FIG. 2 is a control block diagram of a controller according to the first embodiment.

FIG. 3 is a diagram illustrating a second embodiment of the present invention and corresponding to FIG. 1;

FIG. 4 is a view corresponding to FIG. 2 showing a second embodiment of the present invention.

FIG. 5 is a view corresponding to FIG. 1 showing a conventional sub-chamber torch ignition type gas engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Controller 3 Gas pressure control device 4 Gas supply pipe 5 Sub chamber valve 6 Sub chamber upper hardware 6a Gas chamber 6b Gas passage 7 Spark plug 8 Cylinder head 9 Sub chamber base 10 Main combustion chamber 11 Sub combustion chamber 11a Injection port 12 Laser drive device Reference Signs List 13 YAG laser 14 Dye laser 15 Wavelength converter 16, 19 Optical fiber 17 Laser beam incident probe 18 Detected light receiving probe 20 Optical filter 21 Photodetector 25 Semiconductor laser 51 Fuel gas concentration calculating unit 52 Gas concentration comparing unit 53 Proper gas concentration Setting unit 54 Gas pressure adjustment amount calculation unit 55 Gas pressure adjustment amount output unit 56 Oxygen concentration conversion unit

[Procedure amendment]

[Submission date] August 21, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

Further, the present invention preferably provides the above-mentioned concentration detecting means.
The stage is configured to include means for receiving a laser beam incident on the sub-combustion chamber and performing optical measurement.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

In addition, the detection of the concentration of the fuel gas in the sub-combustion chamber can be performed by a high-precision optical measurement method capable of performing non-contact measurement with high temporal and spatial resolution. Can be realized.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction contents]

Further, the detection of the fuel gas concentration in the sub-combustion chamber 11 has a high time and spatial resolution and can be measured without contact.
A simple optical measurement method can be applied, and high-precision control can be realized.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0050

[Correction method] Change

[Correction contents]

In this embodiment, the semiconductor laser 2
5 is incident on the sub-combustion chamber 11 to detect the oxygen concentration in the sub-combustion chamber 11, calculate the fuel gas concentration based on this, and calculate the fuel gas concentration in accordance with the fuel gas concentration. 11 to control the pressure of the torch fuel gas into
The time and spatial resolution for detecting the oxygen concentration in the sub-combustion chamber 11 are high, and the non-contact measurement is performed in the same manner as in the first embodiment.
An optical measurement method capable of measurement can be applied, and high-precision control can be realized.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 21/02 301 F02M 21/02 301A

Claims (3)

[Claims] 1. A fuel gas for igniting a torch is guided to a sub-combustion chamber provided in a cylinder head through a gas supply pipe, and the fuel gas is ignited by a spark plug. A sub-chamber torch ignition type gas engine configured to blow out the air-fuel mixture to burn the air-fuel mixture, wherein a concentration detection unit for detecting a fuel gas concentration or an oxygen concentration in the sub-combustion chamber; Gas pressure control means for controlling the pressure of the torch ignition fuel gas to the sub-combustion chamber based on the detected fuel gas concentration or the fuel gas concentration calculated based on the detected oxygen concentration. A fuel supply device for a sub-chamber torch ignition type gas engine. 2. A fuel supply system for a sub-chamber torch ignition type gas engine according to claim 1, wherein said concentration detecting means includes means for receiving a laser beam incident into said sub-combustion chamber and performing optical measurement. 3. The fuel for a sub-chamber torch ignition type gas engine according to claim 1, wherein said concentration detecting means is configured to detect a fuel gas concentration or an oxygen concentration near a spark plug in a sub-combustion chamber. Feeding device.