JP6262491B2 - Gas fuel engine - Google Patents

Description

  The present invention relates to a gas fueled engine.

  As an engine for preventing backfire, as disclosed in Patent Document 1, combustion air and gas fuel are supplied to a combustion chamber through an intake pipe, and a flame arrester having a number of elongated through holes is provided in the intake pipe. There is something to be.

  That is, in the engine described in Patent Document 1, combustion air is introduced from an air intake provided upstream of the intake pipe, and fuel injected from the fuel injector is connected to the intake port of each cylinder in the intake pipe. The air-fuel mixture having a predetermined air-fuel ratio is formed. The air-fuel mixture is supplied to each cylinder from the intake port, and is used for combustion in the combustion chamber of each cylinder.

  And in the engine of patent document 1, the flame arrester is arrange | positioned in the upstream of the fuel injector in an intake pipe. Backfire, in which the flame in the combustion chamber flows back to the intake pipe side from the intake port opened by the intake valve, is extinguished by the flame arrester upstream of the fuel injector, and the flame goes upstream from the flame arrester of the intake pipe Can be prevented.

  At this time, as a frame arrester, unlike a metal mesh or the like, a metal honeycomb cylindrical body having a large number of elongated through holes is used, and those through holes subdivide the flame of the backfire to reduce its pressure. Can prevent the reverse flow of the flame, and further absorb the heat by the long surface area of the through-hole in contact with the flame to lower the temperature of the flame, thereby preventing the propagation of the flame, thereby ensuring the extinction of the flame. .

JP2000-46069

  However, in the engine described in Patent Document 1, it is necessary to avoid a reduction in the efficiency of intake of the fuel into the combustion chamber due to a large passage resistance based on the large surface area of the many elongated through holes of the frame arrester. The flame arrester is arranged upstream of the fuel injector in the intake pipe. Only the combustion air passes through the through hole of the flame arrester, and the fuel injected from the fuel injector is supplied to the combustion chamber without passing through the through hole of the flame arrester.

  Therefore, the engine described in Patent Document 1 has the following problems when trying to use gas fuel such as CNG (compressed natural gas) and LPG (liquefied petroleum gas) as the fuel.

(1) A fuel injector for injecting gaseous fuel is installed at a portion connected to the intake port of each cylinder. Therefore, the gas fuel injected from the fuel injector is only mixed with the combustion air in a short path from the intake port to the combustion chamber, and it is difficult to mix the gas fuel and the combustion air sufficiently evenly. There is a possibility that the combustion state in the combustion chamber by such an air-fuel mixture becomes unstable. Such instability of combustion becomes more conspicuous at the time of using a crude gas fuel with unstable fuel components (content of CH ₄ or the like).

  (2) The many elongated through holes of the flame arrester give direction to the flow of combustion air passing therethrough, but do not affect the flow of gas fuel that does not pass therethrough. Therefore, the flow direction of the mixture of gas fuel and air in the intake pipe (distribution of the mixture from the intake pipe to each cylinder, etc.) despite the use of a flame arrester having a large number of elongated through holes It is difficult to improve the combustion efficiency in the combustion chamber by such an air-fuel mixture.

  An object of the present invention is to stabilize the combustion state and improve the combustion efficiency by the mixture of gas fuel and combustion air while preventing backfire in an engine using gas fuel.

The invention according to claim 1 is an engine using gas fuel in which combustion air and gas fuel are supplied to a combustion chamber by an intake pipe, and a flame arrester having a number of elongated through holes is provided in the intake pipe. The combustion air is introduced from the air intake provided upstream of the intake pipe, and the gas fuel is supplied from the gas outlet to the intake pipe, and the mixture of the air and the gas fuel mixed in the intake pipe is supplied to the intake pipe. Via the intake port that is opened and closed by the intake valve via, and a flame arrester is disposed downstream of the gas outlet in the intake pipe, and downstream of the gas outlet in the intake pipe, A partition portion for partitioning the upstream portion and the downstream portion of the intake pipe is provided, the downstream portion of the partition portion is a surge tank, and a frame arrester is disposed in the partition portion .

According to a second aspect of the present invention, in the first aspect of the invention, a throttle valve is further arranged at a position spaced downstream from the gas outlet in the intake pipe, and a surge is caused downstream of the throttle valve in the intake pipe. A tank is provided, and the frame arrester is disposed between a throttle valve and a surge tank in the intake pipe .

The invention according to claim 3 is an engine using gas fuel in which combustion air and gas fuel are supplied to a combustion chamber by an intake pipe, and a flame arrester having a number of elongated through holes is provided in the intake pipe. The combustion air is introduced from the air intake provided upstream of the intake pipe, and the gas fuel is supplied from the gas outlet to the intake pipe, and the mixture of the air and the gas fuel mixed in the intake pipe is supplied to the intake pipe. And is supplied to the combustion chamber from an intake port that is opened and closed by an intake valve via a flame arrester disposed downstream of the gas outlet in the intake pipe and spaced from the gas outlet in the intake pipe downstream. And a surge tank is provided downstream of the throttle valve in the intake pipe, and the frame arrester is connected to the throttle valve and surge valve in the intake pipe. Click is obtained by way become disposed between the.

The invention according to claim 4 is the invention according to any one of claims 1 to 3 , wherein a sensor for detecting an intake state in the intake pipe is provided only in an upstream portion of the frame arrester. is there.

The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the frame arrester is made of metal .

(Claims 1 and 3 )
(a) Combustion air is introduced from an air intake provided upstream of the intake pipe, gas fuel is supplied from the gas outlet to the intake pipe, and the mixture of air and gas fuel mixed in the intake pipe is While supplying to the combustion chamber from the intake port opened and closed by the intake valve via the intake pipe, a flame arrester was disposed downstream of the gas outlet in the intake pipe. As a result, in the engine using gas fuel that is less ignitable than gasoline fuel and the fuel component (content of CH ₄ etc.) is unstable and is likely to cause backfire, many long holes in the flame arrester are By reducing the pressure of the fire flame and reducing its pressure, the reverse flow of the flame is prevented, and the large surface area of the through-hole that contacts the flame absorbs the heat and lowers the flame temperature, resulting in flame propagation. By preventing it, it is possible to ensure the extinction of the flame.

  The flame arrester is preferably arranged on the downstream side of the throttle valve in the downstream side of the gas outlet in the intake pipe.

  (b) A flame arrester is disposed on the downstream side of the gas outlet, and gas fuel, combustion air, and a mixture thereof are passed through a number of elongated through holes of the flame arrester. In spite of the passage resistance, it was found that these gases were passed smoothly and did not adversely affect the intake efficiency of the mixture into the combustion chamber. Because gas fuels such as CNG and LPG, which are different from liquids such as gasoline, are used as fuel, they are hardly affected by passage resistance due to wettability that can occur with liquids on the long surface of those through holes. It is thought to be due to.

  (c) The gas outlet is installed upstream of the flame arrestor in the intake pipe, and the gas fuel supplied from the gas outlet is mixed with combustion air in a long path from the intake pipe to the combustion chamber. The The gas fuel and the combustion air are sufficiently evenly mixed along the long path, and such a mixture can stabilize the combustion state in the combustion chamber.

  The flammable mixture of gas fuel and combustion air fills the long path from the intake pipe to the combustion chamber, causing the backfire blast to spread to the air cleaner upstream of the intake pipe. However, the risk of such backfire can be reliably prevented by the above-mentioned (a).

  (d) Gas fuel is filled in the elongated through holes of the flame arrester together with the combustion air and allowed to pass through. After a mass of gas fuel and a mass of combustion air that are not sufficiently mixed with each other in the intake pipe on the upstream side of the flame arrestor and are filled with combustion air are filled in the elongated through holes of the flame arrester in a turbulent state, When it flows out of the through hole, it becomes a laminar flow that is subdivided to promote mixing with each other. The gas fuel and the combustion air pass through a large number of elongated through holes of the flame arrester and are mixed sufficiently evenly, so that the combustion state in the combustion chamber can be stabilized by such an air-fuel mixture.

  (e) A number of elongated through holes in the flame arrestor impart directionality to the flow of the mixture of combustion air and gas fuel passing therethrough. Therefore, the direction of the flow of the mixture of gas fuel and combustion air in the intake pipe depends on the orientation of the arrangement in the intake pipe and the setting of the axial direction of the hole of the through hole. (Such as the distribution of the air-fuel mixture from the intake pipe to each cylinder) and the direction of the flow from the intake port of each cylinder to the combustion chamber (swirl and tumble effect). The combustion efficiency in the combustion chamber can be improved.

(Claim 1 )
(f) By using a surge tank at the downstream part of the partition where the frame arrester is provided, the supply amount of the air-fuel mixture to each cylinder can be equalized, and the combustion state in the combustion chamber of each cylinder can be stabilized. . At the same time, the backfire can be stopped in the surge tank, and at the same time, the propagation of flame to the upstream side can be prevented.

(Claims 2 and 3)
(g) By disposing the gas outlet upstream from the throttle valve, gas fuel and combustion air are mixed sufficiently evenly in the longer path from the gas outlet to the throttle valve and further to the combustion chamber. it can.

  Since the flame arrester is disposed between the throttle valve and the surge tank, it is possible to prevent the backfire from reaching the throttle valve, and to avoid the occurrence of damage such as deformation of the throttle valve due to the explosive force of the backfire.

  The mixture of the gas fuel and the combustion air whose flow rate is adjusted by the throttle valve is given the above-described flow direction by the flame arrester. When the air-fuel mixture that has passed through the flame arrestor is supplied to each cylinder via the surge tank, the air-fuel mixture is distributed to each cylinder based on the orientation of the flame arrester in the intake pipe and the setting of the axial direction of the through hole. Can be made even.

(Claim 4 )
(h) A sensor for detecting an intake state in the intake pipe is provided only in the upstream portion of the frame arrester, and is not provided in the downstream portion thereof. Therefore, it is possible to avoid the occurrence of inconvenience such as damage to the sensor due to the explosive force of the backfire.

(Claim 5 )
(i) When the frame arrester is made of metal, its heat capacity is large, and flame extinguishing performance can be improved.

FIG. 1 is a schematic diagram showing Example 1 of an engine using gas fuel. FIG. 2 is a schematic diagram showing a second embodiment of the engine using gas fuel. FIG. 3 is a schematic view showing Reference Example 1 of an engine using gas fuel.

Example 1 (FIG. 1)
The gas fuel-using engine 100 shown in FIG. 1 is, for example, a six-cylinder four-cycle engine, and introduces combustion air (A) from an air intake 11A of an air cleaner 11 provided upstream of the intake pipe 10. At the same time, the gas fuel-using engine 100 supplies gas fuel (G) such as CNG, LPG or the like to the intake pipe 10 from the gas outlet 12 </ b> A of the fuel injector 12 provided in the middle part of the intake pipe 10. The fuel injector 12 adjusts the pressure of the gas fuel pressurized in the cylinder to a constant pressure using a pressure regulating valve, and injects the gas fuel into the intake pipe 10 at a constant injection timing. The gas fuel-using engine 100 opens and closes an air-fuel mixture of air and gas fuel mixed in the intake pipe 10 at a predetermined air-fuel ratio via the intake pipe 10 by an intake valve of each cylinder 13. 14 is supplied to a combustion chamber (not shown) and combusted.

  The gas fuel-using engine 100 does not use the fuel injector 12 but applies the negative intake pressure generated in the venturi portion in the intake pipe 10 to the gas outlet 12A formed in the venturi portion. Gas fuel may be sucked out from 12A and ejected. Further, in the gas fuel-using engine 100, a turbocharger that supercharges combustion air and an intercooler that cools the supercharged air can be installed between the air cleaner 11 and the gas outlet 12A in the intake pipe 10.

  In the gas fuel-using engine 100, the flame arrester 30 is disposed on the downstream side of the gas outlet 12 </ b> A in the intake pipe 10.

  At this time, the engine 100 using gas fuel is provided with a partitioning portion 16 for partitioning the upstream portion and the downstream portion of the intake pipe 10 on the downstream side of the gas outlet 12A in the intake pipe 10, and the downstream portion of the partitioning portion 16 is provided. A surge tank 17 is used, and a frame arrester 30 is disposed in the partition 16. The surge tank 17 communicates with the combustion chambers via the intake port 14 of each cylinder 13. In the present embodiment, the partition 16 divides the first surge tank 17A that can communicate with the left three cylinders and the second surge tank 17B that can communicate with the right three cylinders. The first frame arrester 30A is connected to the first partition 16A that partitions the first surge tank 17A, and the second partition 16B that partitions the second surge tank 17B is connected to the second partition 16B. Frame arrester 30B.

  In the gas fuel-using engine 100, the throttle valve 20 is disposed at a position spaced downstream from the gas outlet 12 </ b> A in the intake pipe 10, and the expansion line 15 is provided downstream of the throttle valve 20 in the intake pipe 10. The first and second surge tanks 17A and 17B described above are provided. The flame arrester 30 (first and second flame arresters 30A, 30B) is disposed between the throttle valve 20 and the surge tank 17 (first and second surge tanks 17A, 17B) in the intake pipe 10. Become a thing. In addition, the intake pipe 10 expands the flow passage area of the expansion pipe 15 more than the upstream portion where the gas outlet 12 </ b> A and the throttle valve 20 are disposed, and the flow passage volumes of the surge tanks 17 </ b> A and 17 </ b> B than the expansion pipe 15. Expanded.

  In addition, the engine 100 using gas fuel is provided with sensors 41 and 42 for detecting the intake state in the intake pipe 10 only in the upstream portion of the frame arrester 30 (30A and 30B). For example, the sensor 41 provided on the upstream side of the throttle valve 20 in the intake pipe 10 is, for example, a detection sensor for the intake flow rate, the intake negative pressure, etc., and the sensor 42 provided on the downstream side of the throttle valve 20 in the intake pipe 10 is, for example, the intake pipe. This is a sensor for detecting the temperature and pressure of the air-fuel mixture.

  Here, in the engine 100 using gas fuel, the flame arrestor 30 (30A, 30B) has a number of elongated through holes, and the surge tank 17 (17A) of the intake pipe 10 from the intake port 14 opened by the intake valve of the combustion chamber. 17B), the backfire that flows back to the flame arrester 30 is extinguished by the flame arrester 30 to prevent the flame from propagating upstream from the flame arrester 30. The combustion air, gas fuel, and mixture thereof supplied to the intake pipe 10 pass through the elongated through holes of the flame arrester 30 (30A, 30B) to the surge tank 17 (17A, 17B) side. And will be distributed.

  The frame arrester 30 may be a honeycomb-like cylinder or prism having a large number of through holes that are wound around at least one metal corrugated plate and have a mesh shape in the cross section and extend in the axial direction. Specifically, for example, those described in JP-A-2006-46069 can be employed.

  The flame arrester 30 has a large number of elongated through holes in a mesh shape, and in order to ensure the excellent flame extinguishing properties of the backfire and the smooth flowability of the combustion air, gas fuel, and mixtures thereof, Therefore, it is necessary to optimize the roughness of the mesh composed of the elongated through holes. The above-mentioned mesh roughness in the flame arrester 30 is good in flame extinguishing properties and good flowability when it is 400 Cpsi (squares of pieces / inch) to 700 Cpsi. If the mesh is coarser than 400 Cpsi, the flame-extinguishing property is poor, and if it is finer than 700 Cpsi, the flowability is poor. In addition, although the influence of the hole length (the axial length of the hole) on the flame extinguishing property and flowability of the flame arrestor 30 was small, it was recognized that the preferable value range was 25 to 50 mm.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) Combustion air is introduced from an air intake 11A provided upstream of the intake pipe 10, and gas fuel is supplied from the gas outlet 12A to the intake pipe 10 so that the air and gas mixed in the intake pipe 10 are mixed. A fuel mixture is supplied to the combustion chamber from an intake port 14 that is opened and closed by an intake valve via the intake pipe 10 and downstream of the gas outlet 12A in the intake pipe 10 (preferably downstream of the throttle valve 20). A frame arrester 30 was disposed on the side. As a result, in an engine using gas fuel that is less ignitable than gasoline fuel and has unstable fuel components (content of CH ₄ or the like) and is likely to generate backfire, a large number of long hole-shaped through holes of the flame arrester 30 are formed. The backfire flame is refined and the pressure is reduced to prevent backflow of the flame, and the heat is absorbed by the large surface area of the through-hole that contacts the flame to lower the flame temperature, resulting in flame propagation By preventing this, it is possible to ensure the extinction of the flame.

  (b) A flame arrester 30 is disposed downstream of the gas outlet 12A, and gas fuel, combustion air, and a mixture thereof are passed through a number of elongated through holes of the flame arrester 30. Despite the passage resistance on the surface of the holes, it was found that these gases were passed smoothly and did not adversely affect the intake efficiency of the mixture into the combustion chamber. Because gas fuels such as CNG and LPG, which are different from liquids such as gasoline, are used as fuel, they are hardly affected by passage resistance due to wettability that can occur with liquids on the long surface of those through holes. It is thought to be due to.

  (c) The gas outlet 12A is installed on the upstream side of the flame arrestor 30 in the intake pipe 10, and the gas fuel supplied from the gas outlet 12A burns in a long path from the intake pipe 10 to the combustion chamber. Mixed with working air. The gas fuel and the combustion air are sufficiently evenly mixed along the long path, and such a mixture can stabilize the combustion state in the combustion chamber.

  The flammable mixture of gas fuel and combustion air fills a long path from the intake pipe 10 to the combustion chamber, so that the backfire blast propagates to an air cleaner or the like upstream of the intake pipe 10. In spite of such a risk, the risk of such backfire can be reliably prevented by the aforementioned (a).

  (d) Gas fuel is filled in the elongated through holes of the flame arrester 30 together with the combustion air and allowed to pass therethrough. In the intake pipe 10 on the upstream side of the flame arrester 30, each of the elongated through holes of the flame arrester 30 is filled in a turbulent state with a mass of gas fuel and a mass of combustion air that are not sufficiently mixed with each other and are unevenly distributed. Then, when it flows out from the through hole, it becomes a subdivided laminar flow, and mixing with each other is promoted. The gas fuel and the combustion air pass through a number of elongated through holes of the flame arrester 30 and are sufficiently evenly mixed, and the combustion state in the combustion chamber can be stabilized by such an air-fuel mixture.

  (e) The many elongated through holes of the flame arrestor 30 give directionality to the flow of the mixture of combustion air and gas fuel passing therethrough. Accordingly, the frame arrester 30 having a large number of elongated through holes is arranged in the intake pipe 10 for the mixture of gas fuel and combustion air depending on the orientation of the intake pipe 10 and the setting of the through hole axial direction. In the flow direction (distribution of the air-fuel mixture from the intake pipe 10 to each cylinder) and the flow direction from the intake port 14 of each cylinder to the combustion chamber (swirl and tumble effect) The combustion efficiency in the combustion chamber by such an air-fuel mixture can be improved.

  (f) By using the surge tank 17 as the downstream portion of the partition 16 where the frame arrester 30 is provided, the supply amount of the air-fuel mixture to each cylinder is equalized, and the combustion state in the combustion chamber of each cylinder is stabilized. be able to. At the same time, the backfire can be stopped in the surge tank 17, and at the same time, the propagation of the flame to the upstream side can be prevented.

  (g) By disposing the gas outlet 12A on the upstream side of the throttle valve 20, the gas fuel 12 and the combustion air are supplied to the gas outlet 12A to the throttle valve 20 and further to the combustion chamber in a longer path. Can be mixed evenly enough.

  Since the flame arrester 30 is disposed between the throttle valve 20 and the surge tank 17, the backfire is prevented from reaching the throttle valve 20, and damage such as deformation of the throttle valve 20 due to the backfire explosive force is generated. Can be avoided.

  The mixture of the gas fuel and the combustion air whose flow rate is adjusted by the throttle valve 20 is given the above-described flow direction by the flame arrester 30. When the air-fuel mixture that has passed through the frame arrester 30 is supplied to each cylinder via the surge tank 17, it is sent to each cylinder based on the position of the flame arrester 30 in the intake pipe 10 and the setting of the axial direction of the through hole. The air-fuel mixture can be evenly distributed.

  (h) The sensors 41 and 42 for detecting the intake state in the intake pipe 10 are provided only in the upstream portion of the frame arrester 30 and are not provided in the downstream portion thereof. Therefore, it is possible to avoid the occurrence of inconvenience such as damage to the sensors 41 and 42 due to the explosive force of the backfire.

  (i) When the frame arrester 30 is made of metal, its heat capacity and heat transfer coefficient are large, and flame extinguishing performance can be improved. However, the frame arrester 30 is not necessarily made of metal, and may be ceramics or the like.

Example 2 (FIG. 2)
The engine 100 using the gas fuel according to the second embodiment is different from the engine 100 using the gas fuel according to the first embodiment in that a gas jet 12A in the intake pipe 10 and a partition 16 provided on the downstream side of the throttle valve 20 The surge tank 17 (not divided into the first and second surge tanks 17A and 17B) is provided, and a single frame arrester 30 is provided in the partition portion 16.

  According to the present embodiment, the same operational effects as in the first embodiment can be obtained.

( Reference Example 1 ) (Fig. 3)
The difference between the gas fuel using engine 100 of the reference example 1 and the gas fuel using engine 100 of the first and second embodiments is that the partition 16 is not provided on the downstream side of the gas outlet 12A and the throttle valve 20 in the intake pipe 10. A surge tank 17 that communicates directly with each other is provided, and a flame arrester 30 is provided in each intake port 14 that communicates the surge tank 17 with the combustion chamber of each cylinder 13.

According to the present reference example , the following effects are achieved as well as the effects (a) to (e) and (g) to (i) described in the first embodiment.

  That is, since the frame arrester 30 is disposed in the intake port 14, the air-fuel mixture supplied from the intake port 14 of each cylinder 13 to the fuel chamber is given the above-described flow direction. When the air-fuel mixture that has passed through the flame arrester 30 is supplied from the intake port 14 of each cylinder 13 to the combustion chamber, the orientation of the flame arrester 30 in the intake port 14 and the setting of the hole axial direction of the through-hole The swirl (swirl flow around the cylinder axis) and tumble (swirl flow around the axis perpendicular to the cylinder axis) of the air-fuel mixture generated in the combustion chamber can be controlled.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention. For example, the present invention can be widely applied to an engine having a combustion structure in which combustion air and gas fuel are mixed in an intake pipe and supplied to a combustion chamber, and is used by switching between gas fuel and liquid fuel such as gasoline. It can also be applied to fuel engines.

  According to the present invention, it is possible to stabilize the combustion state and improve the combustion efficiency by the mixture of gas fuel and combustion air while preventing backfire in the engine using gas fuel.

DESCRIPTION OF SYMBOLS 10 Intake pipe 11A Air intake 12A Gas injection port 13 Cylinder 14 Intake port 16, 16A, 16B Partition part 17, 17A, 17B Surge tank 20 Throttle valve 30, 30A, 30B Flame arrester 100 Gas fuel use engine

Claims (5)

An engine using gas fuel, in which combustion air and gas fuel are supplied to a combustion chamber by an intake pipe, and a flame arrester having a number of elongated through holes is provided in the intake pipe,
Combustion air is introduced from an air intake provided upstream of the intake pipe, gas fuel is supplied from the gas outlet to the intake pipe, and the mixture of air and gas fuel mixed in the intake pipe passes through the intake pipe. Is supplied to the combustion chamber from an intake port that is opened and closed by an intake valve.
While arranging a flame arrester on the downstream side of the gas outlet in the intake pipe ,
A partition for partitioning the upstream and downstream portions of the intake pipe is provided on the downstream side of the gas outlet in the intake pipe. The downstream portion of the partition is a surge tank, and a frame arrester is provided in the partition. An engine using gas fuel. The throttle valve is disposed at a position spaced downstream from the gas outlet in the intake pipe, and a surge tank is provided on the downstream side of the throttle valve in the intake pipe,
The engine using gas fuel according to claim 1, wherein the frame arrester is disposed between a throttle valve and a surge tank in the intake pipe . An engine using gas fuel, in which combustion air and gas fuel are supplied to a combustion chamber by an intake pipe, and a flame arrester having a number of elongated through holes is provided in the intake pipe,
Combustion air is introduced from an air intake provided upstream of the intake pipe, gas fuel is supplied from the gas outlet to the intake pipe, and the mixture of air and gas fuel mixed in the intake pipe passes through the intake pipe. Is supplied to the combustion chamber from an intake port that is opened and closed by an intake valve.
While arranging a flame arrester on the downstream side of the gas outlet in the intake pipe,
The throttle valve is disposed at a position spaced downstream from the gas outlet in the intake pipe, and a surge tank is provided on the downstream side of the throttle valve in the intake pipe,
Provided by a gas fuel engine use comprising between the throttle valve and the surge tank wherein the flame arrestor is in the intake pipe. The gas fuel use engine according to any one of claims 1 to 3 , wherein a sensor for detecting an intake state in the intake pipe is provided only in an upstream portion of a frame arrester. The engine using gas fuel according to any one of claims 1 to 4 , wherein the frame arrester is made of metal.

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