JP2008075642A - Fuel supply mechanism and engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize stable combustion and low exhaust emission when supplying gaseous fuel to an intake passage on an upstream side of a branch part to intake ports in an engine provided with a pair of intake ports with respect to one combustion chamber, by sending the gaseous fuel almost evenly into respective inflow parts of the intake ports. <P>SOLUTION: The fuel supply mechanism is provided with a straight pipe member 51 arranged across the intake passage along boundary surfaces of the pair of intake ports 13, 14 and supplied with the gaseous fuel G into an interior, and a plurality of jet holes 52, 53 jetting out the fuel G is bored in a side wall of the pipe member 51. It is provided with a means for turning the pipe member 51 around a pipe axis X to adjust jetting directions of the holes 52, 53. The plurality of holes 52, 53 has a first hole 52 group formed so as to jet out the gaseous fuel G toward an inflow part 13a in one side, and a second hole 53 group formed so as to jet out the gaseous fuel G toward an inflow part 14a in another side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine provided with a pair of intake ports for one combustion chamber, and a fuel supply mechanism for supplying gaseous fuel to an intake passage upstream of a branch portion to the pair of intake ports in the engine. About.

  Conventionally, in an engine that uses gaseous fuel such as natural gas as a fuel, it is difficult to inject the gaseous fuel directly into the combustion chamber at a high pressure. In some cases, the air-fuel mixture is configured to be sucked into the combustion chamber through the intake port (see, for example, Patent Document 1).

Further, as an engine for supplying fuel to the intake passage, a pair of intake ports are provided for one combustion chamber in order to improve the charging efficiency of the air-fuel mixture from the intake passage to the combustion chamber. There has been known one provided with a fuel supply mechanism for supplying fuel to an intake passage on the upstream side of the branching section (see, for example, Patent Document 2).
That is, in this type of engine, fuel is supplied from the fuel supply mechanism in the intake passage to form an air-fuel mixture, and the air-fuel mixture is divided into a pair of intake ports and mixed into the combustion chamber through each of the pair of intake ports. Qi will be inhaled.

Japanese Patent Laid-Open No. 11-294222 Japanese Patent Laid-Open No. 11-294242

  As described above, in an engine in which a pair of intake ports are provided for one combustion chamber, inflow of fuel to each of the pair of intake ports is uneven when supplying fuel to the intake passage by the fuel supply mechanism. If so, the concentration of the air-fuel mixture in the combustion chamber becomes inhomogeneous, which may cause problems such as the occurrence of unstable combustion such as misfire and knocking, and an increase in exhaust emissions such as NOx and unburned components.

  Further, when liquid fuel such as gasoline is used as the fuel, the fuel can be supplied evenly to the pair of intake ports by increasing the injection pressure of the liquid fuel and using the penetrating force of the injected liquid fuel. . However, when using a gaseous fuel such as natural gas as the fuel, it is difficult to increase the fuel injection pressure, and thus the variation in the gaseous fuel supplied to each of the pair of intake ports is likely to occur and is unstable. Problems such as combustion and increased exhaust emissions are likely to occur.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a bifurcated portion to a pair of intake ports by a fuel supply mechanism in an engine provided with a pair of intake ports for one combustion chamber. When supplying gaseous fuel to the upstream intake passage of the engine, it is possible to provide a technique capable of realizing stable combustion and low exhaust emission by allowing gaseous fuel to flow into each inflow portion of a pair of intake ports substantially evenly. is there.

In order to achieve the above object, a fuel supply mechanism according to the present invention is provided in an engine provided with a pair of intake ports for one combustion chamber in an intake passage upstream of a branch portion to the pair of intake ports. A fuel supply mechanism for supplying gaseous fuel, the first characteristic configuration of which is arranged to cross the intake passage along a boundary surface of the pair of intake ports in the intake passage, and supply the gaseous fuel inside In addition to a straight tubular fuel supply pipe member, a plurality of injection holes for jetting gaseous fuel are formed in the side wall of the fuel supply pipe member.
The fuel supply pipe member is provided with a jetting direction adjusting means capable of rotating the jetting direction of the jetting hole about the pipe axis by rotating the fuel supply pipe member around the pipe axis of the fuel supply pipe member.

  According to the first characteristic configuration, the gaseous fuel supplied into the fuel supply pipe member arranged to cross the intake path along the boundary surface of the pair of intake ports in the intake path is supplied to the fuel supply pipe member. The air is ejected into the intake passage through a plurality of ejection holes formed in the side wall. Further, by rotating the fuel supply pipe member around the pipe axis by the jet direction adjusting means, the jet direction of the plurality of jet holes is adjusted to an appropriate direction around the pipe axis. In addition, the gaseous fuel ejected through the plurality of ejection holes is distributed substantially evenly to the respective inflow portions of the pair of intake ports that diverge on the downstream side. Therefore, in the combustion chamber, it is possible to inhale the gaseous fuel evenly divided from each of the pair of intake ports to form the homogeneous mixture, and as a result, the homogeneous mixture is burned and stable combustion is performed. And exhaust emission reduction can be realized.

A second characteristic configuration of the fuel supply mechanism according to the present invention is a straight tubular shape that is disposed so as to cross the intake passage along a boundary surface of the pair of intake ports in the intake passage, and in which gaseous fuel is supplied. In addition to the fuel supply pipe member, the side wall of the fuel supply pipe member is provided with a plurality of ejection holes for ejecting gaseous fuel.
The plurality of ejection holes are directed to a first ejection hole group formed to eject gaseous fuel toward an inflow portion on one side of the pair of intake ports in the branching portion, and toward an inflow portion on the other side. And a second ejection hole group formed so as to eject gaseous fuel.

  According to the second characteristic configuration, the gaseous fuel supplied into the fuel supply pipe member arranged to cross the intake path along the boundary surface of the pair of intake ports in the intake path is supplied to the fuel supply pipe member. It is ejected to the intake passage through a plurality of ejection holes formed in the side wall. Further, since the gaseous fuel is ejected from each of the first ejection hole group and the second ejection hole group constituting the plurality of ejection holes toward the inflow portions of the pair of intake ports at the branch portion, The respective gaseous fuels flow into the respective inflow portions of the pair of intake ports branched on the downstream side thereof in a substantially uniform manner. Therefore, in the combustion chamber, it is possible to inhale the gaseous fuel evenly divided from each of the pair of intake ports to form the homogeneous mixture, and as a result, the homogeneous mixture is burned and stable combustion is performed. And exhaust emission reduction can be realized.

  According to a third characteristic configuration of the fuel supply mechanism according to the present invention, in addition to the second characteristic configuration, each of the first injection hole group and the second injection hole group has a tube axis direction of the fuel supply pipe member. Along the tube axis direction and arranged alternately along the tube axis direction.

According to the third characteristic configuration, each of the first ejection hole group and the second ejection hole group is arranged in parallel at equal intervals in the tube axis direction over substantially the entire transverse direction of the intake passage. Therefore, the gaseous fuel ejected from the plurality of injection holes will be distributed substantially evenly in the pipe axis direction in the intake passage, and the mixed state of the gaseous fuel and fresh air will be even better. Become.
Furthermore, since each of the plurality of ejection holes constituting the first ejection hole group and the plurality of ejection holes constituting the second ejection hole group are alternately arranged along the tube axis direction, The gaseous fuel ejected from the side ejection hole group will flow well into the inflow portion of the directed intake port without being significantly affected by the ejection pressure of the gaseous fuel from the other ejection hole group Therefore, the gaseous fuel can be more evenly distributed to each of the pair of intake ports.

According to a fourth characteristic configuration of the fuel supply mechanism according to the present invention, in addition to the first to third characteristic configurations, a plurality of nozzle members protruding outward are provided on a side wall of the fuel supply pipe member.
Each of the plurality of ejection holes is formed at a tip end portion of each of the plurality of nozzle members.

According to the fourth characteristic configuration, each of the plurality of ejection holes is formed at the tip of each of the plurality of nozzle members protruding outward from the side wall of the fuel supply pipe, so the fuel supply pipe member The gas fuel can be ejected stably and vigorously from the tip of each nozzle member to the intake passage without being substantially affected by the flow of fresh air formed on the outer surface of the nozzle. Therefore, the gaseous fuel can be more evenly divided into the inflow portions of the pair of intake ports that branch on the downstream side of the intake passage.
Further, since the gaseous fuel can be ejected vigorously, the outer diameter of the fuel supply pipe member can be made relatively small, and the flow resistance by the fuel supply pipe member in the intake passage can be reduced.

  According to a fifth characteristic configuration of the fuel supply mechanism according to the present invention, in addition to the first to fourth characteristic configurations, a cross-sectional shape of the fuel supply pipe member perpendicular to the pipe axis direction The width seen from the flow direction is a flat shape smaller than the width seen from the direction orthogonal to the flow direction.

  According to the fifth characteristic configuration, since the cross-sectional shape of the fuel supply pipe member is the flat shape, flow path resistance due to the fuel supply pipe member in the intake passage can be reduced.

  In order to achieve the above object, an engine according to the present invention is an engine in which a pair of intake ports branched from a common intake passage are connected to a common combustion chamber. As a fuel supply mechanism for supplying gaseous fuel on the upstream side of the branching portion to the pair of intake ports, the fuel supply mechanism having the above-described first to fifth characteristic configurations is provided.

  According to the engine, since the fuel supply mechanism having the characteristic configuration described so far is provided, a pair of intake ports that branch at least downstream of the gaseous fuel injected through the plurality of injection holes into the intake passage. Therefore, stable combustion and reduction of exhaust emission can be realized.

  A fuel supply mechanism according to the present invention and a first embodiment of an engine including the same will be described with reference to the drawings.

[First embodiment]
As shown in FIGS. 1 and 2, the engine 1 includes a combustion chamber 10 that is defined by the inner surface of the cylinder 3, the lower surface of the cylinder head 4, and the top surface of the piston 2, and has an ignition plug 6 at the top, and an intake valve 5. And an intake passage 11 through which an air-fuel mixture M sucked into the combustion chamber 10 flows and an exhaust gas exhausted from the combustion chamber 10 connected to the combustion chamber 10 via an exhaust valve (not shown). An exhaust passage (not shown) is provided.

The intake passage 11 is provided with a fuel supply mechanism 50 that supplies gaseous fuel G, which is natural gas, to the intake passage at a relatively low pressure such as a predetermined supply pressure that is slightly higher than the pressure in the intake passage 11. . That is, gaseous fuel G is supplied to the air (an example of fresh air) A flowing through the intake passage 11 by the fuel supply mechanism 50, and an air-fuel mixture M is formed in the intake passage 11. Then, the air is taken into the combustion chamber 10 through the intake ports 13 and 14 and the intake valve 5.
The engine 1 of this type compresses the intake air-fuel mixture M by the ascending piston 2 in the combustion chamber 10 and expands the compressed air-fuel mixture M by spark ignition combustion with the spark plug 6. The piston 2 is reciprocated, and the reciprocating motion is converted into the rotational power of a crankshaft (not shown) via a connecting rod (not shown) and output. Is done.

  Further, in the engine 1, in order to improve the charging efficiency of the air-fuel mixture M into the combustion chamber 10, a pair of intake ports 13 and 14 are provided for one combustion chamber 10, and the fuel supply mechanism 50 is provided. Is arranged to supply the gaseous fuel G to the intake passage 11 upstream of the branch portion 15 to the pair of intake ports 13 and 14.

  The gaseous fuel G supplied to the intake passage 11 by the fuel supply mechanism 50 is mixed with the air A and is diverted to each of the pair of intake ports 13 and 14 branched at the downstream branching portion 15. .

  The pair of intake ports 13 and 14 is formed as a passage branched from the branch portion 15 in the intake passage 11 to both sides with the branch boundary surface F as a boundary, like a normal two-port intake engine. Each of the pair of intake ports 13 and 14 is connected to the pair of intake valves 5 separately.

Next, a detailed configuration of the fuel supply mechanism 50 provided in the engine 1 described so far will be described.
The fuel supply mechanism 50 is arranged so as to cross the intake passage 11 along the boundary surface F of the pair of intake ports 13 and 14 in the intake passage 11, and is a straight tubular fuel supply pipe member 51 to which the gaseous fuel G is supplied. As shown in FIGS. 3 and 4, a plurality of ejection holes 52 and 53 for ejecting the gaseous fuel G are formed radially from the tube axis X in the side wall of the fuel supply pipe member 51. .

That is, the gaseous fuel G supplied into the fuel supply pipe member 51 with appropriate control of the flow rate and supply timing by the control valve is a plurality of ejection holes 52, 53 formed in the side wall of the fuel supply pipe member 51. Through the air intake passage 11.
As the fuel supply pipe member 51, a normal metal pipe whose tip is sealed can be used.

Further, in the engine 1 in which a pair of intake ports 13 and 14 are provided for one combustion chamber 10 in this way, when the gaseous fuel G is supplied to the intake passage 11 by the fuel supply mechanism 50, a pair of intake ports It is important in terms of stable combustion and reduction of exhaust emission that the gaseous fuel G is allowed to flow evenly into each of 13 and 14 so that a substantially homogeneous mixture M exists in the combustion chamber 10.
Below, the characteristic structure of the fuel supply mechanism 50 for making gaseous fuel G flow in equally with respect to each of a pair of intake ports 13 and 14 is demonstrated.

In the fuel supply mechanism 50, as shown in FIGS. 1 and 4A, the fuel supply pipe member 51 is rotated around the tube axis X of the fuel supply pipe member 51 to eject the ejection holes 52 and 53. An ejection direction adjusting means 54 capable of adjusting the direction around the tube axis X is provided.
That is, the ejection direction adjusting means 54 has a flange portion 55 fixed to the proximal end side of the fuel supply pipe member 51 that penetrates the outer wall 11 a of the intake passage 11, and a long hole shape formed in the flange portion 55. The bolt insertion hole 55a and the bolt 56 inserted into the bolt insertion hole 55a and engaged with the outer wall 11a of the intake passage 11 are realized.
That is, when the bolt 56 is loosened, the fuel supply pipe 51 is rotatable about a predetermined angle (for example, about 10 °) around the pipe axis X, and the fuel supply pipe 51 is moved to an arbitrary rotational position. And can be fixed by the bolt 56.

At the time of assembly manufacture and maintenance of the engine 1, each of the pair of intake ports 13, 14 that branches the gaseous fuel G injected into the intake passage 11 through the plurality of injection holes 52, 53 on the downstream side thereof. The fuel supply pipe member 51 is rotated about the pipe axis X by the jet direction adjusting means 54 so as to flow into the inflow portions 13a, 14a substantially uniformly, and the jets of the plurality of jet holes 52, 53 are ejected. The direction can be adjusted to an appropriate direction around the tube axis X.
In the present embodiment, the ejection direction adjusting means 54 is composed of a flange portion 55 fixed to the base end portion of the fuel supply pipe member 51 and a bolt 56 that fixes the flange portion 55 to the outer wall 11 a of the intake passage 11. Although configured, for example, the base end side of the fuel supply pipe member 51 is rotatably supported on the outer wall 11a of the intake passage 11, and the fuel supply pipe member 51 is fixed by a clamp fixed to the outer wall 11a. Alternatively, the fuel supply pipe member 51 may be appropriately modified, such as a configuration in which the fuel supply pipe member 51 is rotated by a gear mechanism that can be fixed at a predetermined rotation angle.
The ejection direction adjusting means 54 is configured to automatically rotate the fuel supply pipe member 51 around the tube axis X by an actuator, and further, the control unit controls the ejection direction adjusting means 54 to control the fuel. You may comprise so that the rotation angle of the supply pipe member 51 may be adjusted to an appropriate rotation angle according to a driving | running state.

  Further, as shown in FIGS. 2, 3, and 4 (b), in the fuel supply mechanism 50, the plurality of ejection holes 52, 53 are inflow portions on one side of the pair of intake ports 13, 14 in the branch portion 15. A first ejection hole group 52 formed so as to eject gaseous fuel toward 13a, and a second ejection hole group 53 formed so as to eject gaseous fuel toward the inflow part 14a on the other side. In the form, the fuel supply pipe member 51 is formed in the side wall.

  That is, in the side wall of the fuel supply pipe member 51, the first ejection hole 52 is formed as a small hole having a central axis in the direction from the pipe axis X toward the inflow portion 13a of the one intake port 13, The second ejection holes 53 are formed as small holes having a central axis in the direction from the tube axis X toward the inflow portion 14a of the other intake port 14, and specifically, the first ejection holes 52 and the first The respective ejection directions with the two ejection holes 53 are set as directions intersecting at an appropriate angle (for example, about 30 °) in the tube axis X.

Therefore, the gaseous fuel G ejected from the fuel supply pipe member 51 into the intake passage 11 through the first ejection holes 52 mainly flows into the inflow portion 13a of the intake port 13 on one side, The gaseous fuel G ejected through the second ejection holes 53 mainly flows into the inflow portion 14a of the intake port 14 on the other side. Therefore, the gaseous fuel G ejected from the respective ejection holes 52 and 53 into the intake passage 11 flows into the inflow portions 13a and 14a of the pair of intake ports 13 and 14 branched on the downstream side thereof substantially evenly. become.
A small amount of gaseous fuel G out of the gaseous fuel G ejected into the intake passage 11 through the first ejection hole 52 and the second ejection hole 53 is different from the inflow portion in which the ejection direction of the ejection hole is directed. You may flow in into an inflow part.

  Further, as shown in FIG. 3, in the fuel supply mechanism 50, the first injection hole 52 group and the second injection hole 53 group are arranged in parallel at equal intervals in the tube axis X direction of the fuel supply pipe member. The gaseous fuel G ejected from each of the first ejection holes 52 and the second ejection holes 53 is supplied in a substantially uniform manner in the intake passage 11 also in the tube axis X direction.

  Furthermore, the first ejection hole 52 group and the second ejection hole 53 group are alternately arranged along the pipe axis direction over substantially the entire transverse direction of the intake passage 11. The gaseous fuel G ejected from each of the ejection holes 52 and the second ejection holes 53 is satisfactorily and evenly supplied to the inflow portions 13a and 14a of the pair of intake ports 13 and 14 in a state where mutual interference due to the ejection pressure is suppressed. Will flow in.

  The plurality of ejection holes 52 and 53 formed in the fuel supply pipe member 51 are a first ejection hole 52 group and a second ejection hole 53 so that the gaseous fuel G is ejected more uniformly in the intake passage 11. You may provide the ejection holes other than a group, or may change suitably the number of each ejection holes, a drilling direction, an internal diameter, etc. FIG.

  In the above embodiment, as a configuration for allowing the gaseous fuel G to flow evenly into each of the pair of intake ports 13, 14, a configuration including the ejection direction adjusting means 54, and a plurality of ejection holes 52, Although 53 employ | adopted both the structures which have the 1st ejection hole 52 group and the 2nd ejection hole 53 group, you may abbreviate | omit one structure separately.

  Moreover, in said embodiment, although natural gas type | system | group city gas was used as gaseous fuel G, as gaseous fuel G, gaseous fuels other than natural gas type | system | group city gas etc. can also be used.

  Next, a second embodiment and a third embodiment of another form of fuel supply mechanism will be described with respect to the first embodiment. Note that description of the same configuration as in the first embodiment may be omitted.

[Second Embodiment]
In the fuel supply mechanism 60 of the second embodiment, as shown in FIGS. 5 to 7, compared to the fuel supply mechanism 50 described in the first embodiment (see FIGS. 3 and 4), the fuel supply mechanism 60 on the side wall A plurality of nozzle members 66 and 67 projecting in the direction are provided, and further, a plurality of ejection holes 62 and 63 are provided at the respective tip portions of the plurality of nozzle members 66 and 67. The difference is that a pipe member 61 is employed.

  That is, the fuel supply pipe member 61 is a straight tubular member that is disposed so as to cross the intake passage 11 along the boundary surface F of the pair of intake ports 13 and 14 in the intake passage 11 and is supplied with gaseous fuel G therein. In the side wall of the fuel supply pipe member 61, a plurality of openings through which the gaseous fuel G is ejected are formed radially from the tube axis X, and a plurality of ejections are provided at the tip of each of the plurality of openings. A plurality of nozzle members 66 and 67 in which the holes 62 and 63 are formed are provided so as to protrude in the radially outward direction.

  The tip portions of the nozzle members 66 and 67 are hardly affected by the flow of the air A formed on the outer surface of the fuel supply pipe member 61, and thus are formed at the tip portions of the nozzle members 66 and 67. Since the gaseous fuel G is ejected from each of the ejection holes 62 and 63 stably and vigorously, the ejected gaseous fuel G branches as a result on the downstream side of the intake passage 11. , 14 are more evenly distributed to the respective inflow portions 13a, 14a.

  Further, also in the fuel supply pipe member 61, a plurality of ejection holes 62 and 63 are formed so that gaseous fuel is ejected toward the inflow portion 13a on one side, and the inflow on the other side. The nozzle members 66 and 67 are arranged in a form having a second ejection hole 63 group formed so as to eject gaseous fuel toward the portion 14a. Each ejection direction with the ejection hole 63 is set as a direction that intersects the tube axis X at a wider angle (for example, 180 °) than in the first embodiment. Therefore, the gaseous fuel G ejected from the respective ejection holes 62 and 63 is diffused well in the intake passage 11 and is diverted well to the respective inflow portions 13a and 14a.

  Furthermore, since this fuel supply pipe member 61 can eject the gaseous fuel G vigorously and diffuse it over a wide area as described above, the outer diameter of the metal pipe constituting it is as shown in FIG. It is made smaller than the fuel supply pipe member 51 (see FIG. 2) of the first embodiment, and the flow resistance by the fuel supply pipe member 61 in the intake passage 11 is reduced.

  The fuel supply mechanism 60 of the second embodiment is also rotated around the tube axis X of the fuel supply pipe member 61 in the same manner as in the first embodiment, so that the ejection directions of the ejection holes 62 and 63 are changed. An ejection direction adjusting means 64 that can be adjusted around the tube axis X is provided. The ejection direction adjusting means 64 includes a flange portion 65 fixed to the base end side of the fuel supply pipe member 61 that penetrates the outer wall 11a of the intake passage 11 and a long hole shape formed in the flange portion 65. The bolt insertion hole 65a and a bolt (not shown) inserted into the bolt insertion hole 65a and engaged with the outer wall 11a of the intake passage 11 are realized.

[Third embodiment]
In the fuel supply mechanism 70 of the third embodiment, as shown in FIGS. 8 to 10, compared with the fuel supply mechanism 60 (see FIGS. 5 to 7) described in the second embodiment, The cross-sectional shape perpendicular to the cross-sectional shape (the cross-sectional shape shown in FIG. 8) is the width W1 viewed from the flow direction of the air A in the intake passage 11 (the illustrated direction in FIG. 9A). 9 (b) is different in that a fuel supply pipe member 71 having a flat shape smaller than the width W2 as viewed in the drawing direction is employed.

That is, the fuel supply pipe member 71 has a cross-sectional shape that is the above-described flat shape having a relatively small width W1 as viewed in the flow direction of the air A. Therefore, the fuel supply pipe member 71 has a sufficient amount for each of the ejection holes 72 and 73. While supplying the gaseous fuel G, the flow path resistance is reduced by the fuel supply pipe member 71 in the intake passage 11.
Further, as the fuel supply pipe member 71, a bottomed cylindrical member having an elliptical cross-sectional shape can be used. Then, if the fuel supply pipe member 71 having the elliptical cross section is disposed in the intake passage 11 so that the minor axis direction of the elliptical cross section is orthogonal to the flow direction of the air A in the intake passage 11, the flow direction of the air A The seen width W1 can be made to be a relatively small flat shape.

  Further, as in the second embodiment, a plurality of nozzle members 76 and 77 each having a plurality of ejection holes 72 and 73 formed at the tip are provided so as to protrude from the outer wall of the fuel supply pipe member 71. However, the protruding directions of the respective nozzle members 76 and 77 are inclined toward the downstream side of the intake passage 11 with respect to the second embodiment, whereby the first ejection holes 72 and the second ejection holes are formed. The crossing angle of each of the ejection directions with 73 is set to an appropriate angle.

  The fuel supply mechanism 70 of the third embodiment is also rotated around the tube axis X of the fuel supply pipe member 71 in the same manner as in the first embodiment, so that the ejection directions of the ejection holes 72 and 73 are changed. An ejection direction adjusting means 74 that can be adjusted around the tube axis X is provided. The ejection direction adjusting means 74 includes a flange portion 75 fixed to the base end side of the fuel supply pipe member 71 that penetrates the outer wall 11 a of the intake passage 11, and a long hole shape formed in the flange portion 75. The bolt insertion hole 75a and a bolt (not shown) inserted into the bolt insertion hole 75a and engaged with the outer wall 11a of the intake passage 11 are realized.

  In the second and third embodiments, the ejected gaseous fuel G is injected into each inflow portion 13a with respect to the protruding direction, shape, length, number, etc. of the nozzle members 66, 67, 76, 77. , 14a can be appropriately changed so as to be divided equally.

  A fuel supply mechanism according to the present invention and an engine equipped with the fuel supply mechanism include an intake air upstream of a branching portion to a pair of intake ports by the fuel supply mechanism in an engine provided with a pair of intake ports for one combustion chamber. When supplying the gaseous fuel to the road, it can be effectively used as a gas fuel that is made to flow almost uniformly into the inflow portions of the pair of intake ports to realize stable combustion and low exhaust emission.

Elevated sectional view showing a schematic configuration of an intake system of an engine in which the fuel supply pipe member of the first embodiment is arranged Plan sectional drawing which shows schematic structure of the intake system of the engine which has arrange | positioned the fuel supply pipe member of 1st embodiment Elevated view of the fuel supply pipe member of the first embodiment Top view of fuel supply pipe Plan sectional drawing which shows schematic structure of the intake system of the engine which has arrange | positioned the fuel supply pipe member of 2nd embodiment. Elevated view (a) and side view (b) of the fuel supply pipe member of the second embodiment Plan view of the fuel supply pipe member of the second embodiment Plan sectional drawing which shows schematic structure of the intake system of the engine which has arrange | positioned the fuel supply pipe member of 2nd embodiment. Elevated view (a) and side view (b) of the fuel supply pipe member of the second embodiment Plan view of the fuel supply pipe member of the second embodiment

Explanation of symbols

1: Engine 10: Combustion chamber 11: Intake passage 13, 14: Intake port 13a, 14a: Inflow portion 15: Branch portions 50, 60, 70: Fuel supply mechanisms 51, 61, 71: Fuel supply pipe members 52, 53, 62, 63, 72, 73: ejection holes 54, 64, 74: ejection direction adjusting means A: air G: gaseous fuel M: air-fuel mixture F: branch boundary surface X: tube axis

Claims (7)

In an engine provided with a pair of intake ports for one combustion chamber, a fuel supply mechanism for supplying gaseous fuel to an intake passage upstream of a branch portion to the pair of intake ports,
The intake passage includes a straight tubular fuel supply pipe member that is disposed so as to cross the intake path along a boundary surface of the pair of intake ports, and is supplied with gaseous fuel therein. In the side wall provided with a plurality of ejection holes for ejecting gaseous fuel,
A fuel supply mechanism provided with an ejection direction adjusting means capable of adjusting the ejection direction of the ejection hole around the pipe axis by rotating the fuel supply pipe member around the pipe axis of the fuel supply pipe member.   The plurality of ejection holes are directed to a first ejection hole group formed to eject gaseous fuel toward an inflow portion on one side of the pair of intake ports in the branching portion, and toward an inflow portion on the other side. The fuel supply mechanism according to claim 1, further comprising a second ejection hole group formed to eject gaseous fuel. In an engine provided with a pair of intake ports for one combustion chamber, a fuel supply mechanism for supplying gaseous fuel to an intake passage upstream of a branch portion to the pair of intake ports,
The intake passage includes a straight tubular fuel supply pipe member that is disposed so as to cross the intake path along a boundary surface of the pair of intake ports, and is supplied with gaseous fuel therein. In the side wall provided with a plurality of ejection holes for ejecting gaseous fuel,
The plurality of ejection holes are directed to a first ejection hole group formed to eject gaseous fuel toward an inflow portion on one side of the pair of intake ports in the branching portion, and toward an inflow portion on the other side. A fuel supply mechanism having a second ejection hole group formed to eject gaseous fuel.   The first ejection hole group and the second ejection hole group are arranged in parallel at equal intervals along the pipe axis direction of the fuel supply pipe member, and are alternately arranged along the pipe axis direction. The fuel supply mechanism according to any one of claims 2 and 3. A plurality of nozzle members projecting outward are provided on the side wall of the fuel supply pipe member,
The fuel supply mechanism according to any one of claims 1 to 4, wherein each of the plurality of ejection holes is formed at a distal end portion of each of the plurality of nozzle members.   The cross-sectional shape orthogonal to the tube axis direction of the fuel supply pipe member is a flat shape in which a width viewed from a flow direction of fresh air in the intake passage is smaller than a width viewed from a direction orthogonal to the flow direction. The fuel supply mechanism according to any one of 1 to 5. An engine in which a pair of intake ports branched from a common intake passage are connected to a common combustion chamber,
The engine provided with the fuel supply mechanism as described in any one of Claims 1-6 as a fuel supply mechanism which supplies gaseous fuel in the upstream of the branch part to the said pair of intake port in the said intake path.

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