JP2003214259A - Fuel supply device for gas fuel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply device for a gas fuel engine which realizes lean combustion by supplying fuel gas into a cylinder in layers. <P>SOLUTION: A fuel nozzle hole having an injector 3 injecting gas fuel and being supplied with gas fuel from the injector is opened in the vicinity of the upstream side of an intake valve 15. A fuel path 28 leading from the injector 3 to the fuel nozzle hole is formed with a pipe member whose upstream side end is connected with the injector and downstream side end faces in a intake passage wall. The fuel nozzle hole at the down-stream edge of the fuel path 28 is opened near the upstream side of the intake valve 15 in a intake passage 5. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device for a gas fuel engine which supplies gas fuel into an intake passage.

[0002]

2. Description of the Related Art A conventional gas fuel supply device of this type is disclosed in, for example, Japanese Patent Laid-Open No. 6-346800. In the fuel supply device shown in this publication, a mixer for mixing gas fuel with intake air is provided in the middle of an intake pipe connected to the engine. Unlike liquid fuel, the gas fuel supplied into the intake passage by the mixer does not adhere to the wall surface of the intake passage and stay there, so that it is widely dispersed in the intake passage inside the cylinder. Is sucked into.

On the other hand, as an engine using a liquid fuel, an air-fuel mixture formed to be extremely leaner than the stoichiometric air-fuel ratio is supplied to the entire region in the cylinder, and a relatively high concentration is obtained in a narrow region near the periphery of the spark plug. There is one that aims to improve fuel efficiency while supplying the air-fuel mixture in layers so as to stabilize combustion. In this type of engine, in order to collect a relatively rich air-fuel mixture in the vicinity of the spark plug, for example, as disclosed in JP-A-6-257432,
A tumble flow consisting of a vertical swirling flow of intake air is generated in the cylinder, and fuel is injected by an injector toward a branched portion of a bifurcated intake port. That is, the fuel is injected so as to be directed toward the central portion of the cylinder, and the fuel sucked into the cylinder rides on the tumble flow and flows through the cylinder. As a result, the fuel is collected near the periphery of the spark plug in the central portion of the cylinder. Like

[0004]

SUMMARY OF THE INVENTION In the gas fuel engine as well, the inventors have considered that the fuel gas is supplied in layers in the vicinity of the periphery of the spark plug to realize lean combustion and improve fuel efficiency. However, in the conventional gas fuel supply device configured as described above, the fuel gas is mixed with air before being sucked into the combustion chamber and widely dispersed in the intake passage. It could not be supplied to the combustion chamber.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a fuel supply device for a gas fuel engine capable of realizing lean combustion by supplying fuel gas in layers in a cylinder. And

[0006]

In order to achieve this object, a fuel supply system for a gas fuel engine according to the present invention comprises:
An injector for injecting gas fuel is provided, and a fuel injection port to which the gas fuel is supplied from this injector is opened in the intake passage near the upstream side of the intake valve. According to the present invention, the fuel gas supplied from the fuel injection port into the intake passage is sucked into the cylinder in a layered state without being widely dispersed so as to ride on the intake air flowing near the intake valve.

A fuel supply device for a gas fuel engine according to a second aspect of the present invention is the fuel supply device for a gas fuel engine according to the first aspect, wherein fuel gas is supplied from an injector to a fuel injection port of an intake passage. The leading gas fuel passage is formed by a pipe member whose upstream end is connected to the injector and whose downstream end faces the inside of the intake passage, and the opening at the downstream end of this pipe member serves as a fuel injection port.
According to this invention, the degree of freedom of the position where the gas injection port is provided is increased, and the gas injection port can be provided close to the intake port.

A fuel supply system for a gas fuel engine according to a third aspect of the present invention is the fuel supply system for a gas fuel engine according to the first aspect, wherein fuel gas is supplied from an injector to a fuel injection port of an intake passage. The gas fuel passage to be guided is formed by a through hole formed in the wall of the intake passage of the cylinder head and a pipe member connected to the downstream end of the through hole and facing the intake passage, and the downstream end of the pipe member. Is the fuel injection port. According to this invention, the degree of freedom of the position where the gas injection port is provided is increased, and the gas injection port can be provided close to the intake port.

According to a fourth aspect of the present invention, there is provided a fuel supply system for a gas fuel engine according to the second or third aspect, wherein the fuel injection port is located in the intake passage. The opening is formed in a portion close to the spark plug so as to be directed to the downstream side in the intake air flowing direction. According to this invention, the fuel gas flows in the same direction as the intake air without countering the intake air, flows into the cylinder, and is collected in the vicinity of the spark plug.

A fuel supply system for a gas fuel engine according to a fifth aspect of the present invention is the fuel supply system for a gas fuel engine according to the second or third aspect, wherein the fuel injection port is provided with an intake valve. When opened, it is opened so as to direct the gap formed between the intake valve and the valve seat. According to the present invention, the fuel gas is held until the state in which it flows out of the fuel injection port and flows in layers is not disturbed in the direction in which it flows toward the intake valve.

A fuel supply device for a gas fuel engine according to a sixth aspect of the present invention is the fuel supply device for a gas fuel engine according to any one of the first to fifth aspects, wherein: An upstream portion of the gas fuel passage is formed between two intake ports provided for each, and the downstream portion of the gas fuel passage is branched into two branches from the upstream portion and opened to each intake port. Is.

According to the present invention, since the fuel gas can be supplied to the two intake ports from one location on the upstream side of the gas fuel passage, as compared with the case where the fuel gas supply sources are connected to the intake ports, respectively. The structure is simple. Further, by forming the downstream end of the gas fuel passage by the pipe member, the portion protruding into the intake port can be reduced and the increase in intake resistance can be suppressed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) An embodiment of a fuel supply system for a gas fuel engine according to the present invention will be described in detail below with reference to FIGS. 1 to 9. FIG. 1 is a sectional view of a gas fuel engine equipped with a fuel supply device according to the present invention, and FIG. 2 is an enlarged sectional view of a part of the engine, in which the piston is positioned at the top dead center in the compression stroke. It is drawn as it is. 3 is a plan view of the piston, FIG.
FIG. 5 is a plan view showing the configuration of a portion near the combustion chamber of the engine as seen from the cylinder head side, and FIG. 5 is a bottom view showing the combustion chamber wall of the cylinder head. 6 is a longitudinal sectional view of a cylinder and a piston, FIG. 7 is a sectional view taken along line VII-VII in FIG. 1, FIG. 8 is a time chart showing opening / closing timing of an intake / exhaust valve and fuel injection timing, and FIG. It is sectional drawing which shows the example of.

In these figures, the reference numeral 1 indicates an engine according to this embodiment. The engine 1 is operated using a gas fuel such as LPG or CNG (compressed natural gas), and the gas fuel is supplied from an injector 3 for supplying a fuel gas of a cylinder head 2 through a nozzle 4 described later to an intake passage 5 It has a structure to inject inside. The injector 3 and a fuel passage 28, which will be described later, in the cylinder head 2 constitute a gas fuel supply device according to the present invention. It should be noted that the number of cylinders of the engine 1 is shown only for one cylinder in FIG. 1 for convenience of description, but it can be used for an engine having a plurality of cylinders. In FIG. 1, reference numeral 6 indicates a cylinder body,
7 is a piston, and 8 is a connecting rod.

As is well known in the art, the cylinder head 2 is provided with a DOHC type valve operating device 11 and an ignition plug 12, and an intake port 13 and an exhaust port 14 which form the intake passage 5. Is provided. The valve operating device 11 has two intake valves 15 and two exhaust valves 16 for each cylinder.
5 and 16 are driven by an intake cam shaft 18 and an exhaust cam shaft 19 via a valve lifter 17, respectively.

The ignition plug 12 is arranged in the center of the cylinder surrounded by the four intake / exhaust valves 15 and 16. A screw hole into which the ignition plug 12 is screwed is indicated by reference numeral 20 in FIGS. 4 and 5. In FIG. 5, reference numeral 21
Indicates an intake outlet of the intake port 13 opened and closed by the intake valve 15, and 22 indicates an exhaust inlet of the exhaust port 14 opened and closed by the exhaust valve 16.

In this embodiment, the intake port 13 is provided for each intake valve 15 (see FIG. 4), and as shown in FIG. 1, penetrates the cylinder head 2 in the vertical direction (direction along the cylinder axis C). Is formed. Although not shown, the throttle valve is connected to the upstream side of the intake port 13 through an intake passage of the head cover and an intake pipe attached to the head cover.

The intake port 13 according to this embodiment is
As shown in FIG. 1, the cylinder head 2 is inclined so as to gradually approach the intake valve 15 from the opening of the upper end portion toward the downstream side, and is gradually exhausted toward the downstream side to the exhaust valve 16 toward the downstream side. Slope 2 extending to the opposite side of
3 is provided.

By forming the intake port 13 in this manner, the intake air that has passed through the intake port 13 is introduced into the cylinder from the intake outlet 21 in the direction opposite to the exhaust valve 16 due to the inertia of the intake flow. Get burned. On the other hand, in the exhaust port 14, the exhaust passages of the exhaust valves 16 merge in the cylinder head 2, and the exhaust outlet 2 at one side of the cylinder head 2 is joined.
It is formed so as to extend up to 4.

The piston 7 has the structure shown in FIGS.
As shown in, a slope 25 and a recess 26 are formed on the top 7a. As shown in FIGS. 2 and 4, the slope 25 is formed at a portion of the top portion 7 a of the piston 7 that faces the intake valve 15 so as to extend in the direction in which the intake valve 15 is arranged in parallel. End face 15c of valve body 15b
It is inclined so as to be parallel to (a surface forming a part of the combustion chamber wall).

As shown in FIGS. 2 and 6, the recess 26 is formed by denting a portion of the top portion 7a of the piston 7 adjacent to the slope 25, which is D-shaped in plan view, downward in a hemispherical shape. ing. In addition, as the piston 7,
As shown in FIG. 9, a portion of the top portion 7a adjacent to the slope 25 is formed flat, and the flat portion 7b substantially forms the recess 26.
Can also be formed. By using this piston 7, the compression ratio can be increased as compared with the case of using the piston 7 shown in FIG.

The fuel gas injector 3 is provided for each cylinder and is one side of the cylinder head 2.
It is attached to a portion corresponding to between the intake ports 13. In the injector 3, fuel gas is pressure-fed from a fuel tank (not shown), and at a predetermined fuel injection timing, from a fuel injection port 27 (see FIG. 7) at the tip to a fuel passage 28 in the intake passage wall of the cylinder head 2. Inject fuel gas.

As shown in FIG. 8, the fuel injection by the injector 3 is performed at least in the region where lean combustion or EGR is introduced to operate the intake valve 1 in the exhaust stroke.
5 is closed (first fuel supply stroke) and when the intake valve 15 is opened in the intake stroke (second fuel supply stroke), the injection timing and the injection period are respectively corresponding to the operating conditions. Is set. The period during which the injector 3 injects fuel is set to be longer during the first fuel supply stroke than during the second fuel supply stroke.
As the fuel injection amount, for example, about 50 to 70% of the fuel gas supplied in one cycle is injected in the first fuel supply stroke, and the rest is injected in the second fuel supply stroke.

As shown in FIG. 7, the fuel passage 28 through which the injector 3 injects fuel extends from the injector mounting hole 29 toward each intake port 13 and extends toward the intake port 13.
Hole 30 for each intake port 13 opening at the downstream end of the
And a nozzle 4 formed of a pipe fitted into and fixed to each of these through holes 30 from the intake outlet 21 side of the intake port 13.

As shown in FIG. 4, the nozzle 4 is provided in the intake port 13 in the vicinity of the upstream side of the intake valve 15 and in the vicinity of the intake ports 13 adjacent to each other. As shown in, the opening at the tip is opposite to the exhaust valve 16 with respect to the center of the combustion chamber,
It is bent so as to be directed to the downstream side in the direction of intake air flow. The downstream side of the intake flow here means the intake port 13
It means the downstream side of the intake air whose flow direction is restricted by the inclined portion 23, and is the direction from the intake outlet 21 of the intake port 13 opposite to the exhaust valve 16 and directed obliquely downward.

Since the spark plug 12 is arranged on the cylinder axis C (see FIG. 1) of the engine 1, as shown in FIG. 6, by providing the nozzle 4 in each intake port 13 as described above. The nozzle 4 is arranged near the spark plug 12 when viewed from the side. The nozzle 4 constitutes the pipe member according to the present invention, and the opening at the tip constitutes the fuel injection port according to the present invention.

The opening at the tip of the nozzle 4 is shown in FIG.
As shown in FIG.
And the intake outlet 21 (the valve seat of the intake valve 15). Note that the fuel injection ports 27 of the injector 3 are respectively provided at the portions facing the through holes 30, and the fuel gas is directly injected from the fuel injection holes 27 into the through holes 30.

By forming the nozzle 4 in this way, the fuel gas injected from the nozzle 4 into the intake port 13 in the intake stroke is treated by the intake valve 15 as shown by the arrow G filled in black in FIG. Through the gap between the intake port 21 and the intake port 21 and flows obliquely downward in the direction away from the exhaust valve 16 in the cylinder.

In the engine 1 constructed as described above, as shown in FIG. 8, when the piston 7 is rising (when the intake valve 15 is closed) in the exhaust stroke, the first fuel is injected by the injector 3. Injection is performed. At this time,
Since the intake valve 15 is closed, the fuel gas stays in the intake port 13. Then, at the end of the exhaust stroke, the intake valve 15 opens immediately before the piston 7 reaches the top dead center, and the piston 7 stays in the intake port 13 as described above in the descending stroke after the piston 7 exceeds the top dead center. The fuel gas that is operating and fresh air are sucked into the cylinder.

The fuel gas is supplied to the intake valve 15 and the intake outlet 2
1 flows into the cylinder from almost the entire gap between
Most of the air is made to flow in substantially the same direction as the intake air by being pushed by the intake air that is drawn obliquely downward into the cylinder from the intake port 13. The fuel gas and fresh air flow to the lower part in the cylinder along the inner peripheral surface of the cylinder.

As described above, the intake air sucked into the cylinder hits the concave portion 26 of the piston top portion 7a and its flow direction is changed, and a tumble flow is generated in the cylinder as indicated by an arrow T in FIG. This tumble flow is shown in Figure 1.
As shown in FIG. 3, a swirling flow is generally formed such that the intake valve 15 side is separated from the cylinder head 2 with respect to the axis C of the cylinder as viewed from the axial direction of the cam shaft, and the exhaust valve 16 side is close to the cylinder head 2, and The so-called reverse tumble flow is a so-called reverse tumble flow in which the swirling direction is opposite. By forming the tumble flow in this way, the fuel gas is mixed with fresh air and diffused in the cylinder to form a lean air-fuel mixture.

Then, during the intake stroke, the injector 3
The second fuel injection is performed (see FIG. 8). At this time, the fuel gas is injected into the cylinder from each of the two nozzles 4 through the gap between the intake valve 15 and the intake outlet 21. Since the tumble flow T is formed in the cylinder as described above, the fuel gas swirls in the cylinder so as to ride on the tumble flow T as shown in FIG. The nozzle 4 is provided near the portions of the two intake ports 13 that are adjacent to each other.
The fuel injected from the fuel flows in layers near the spark plug 12. That is, at the end of the compression stroke, the spark plug 1
A relatively rich air-fuel mixture is supplied in layers near the periphery of 2.

After the second fuel injection is performed and the intake valve 15 is closed in this way, the piston 7 moves to the compression top dead center, whereby the tumble flow T in the cylinder is
As shown in, the diameter is reduced while swirling in the space (combustion chamber 32) formed between the recess 26 of the piston top portion 7a and the combustion chamber wall 31 on the cylinder head 2 side. On the other hand, at this time, the air-fuel mixture is pushed out from the gap (squish area) between the slope 25 of the piston top portion 7a and the combustion chamber wall 31 on the cylinder head 2 side, and a squish flow is generated.
This squish flow is indicated by arrow S in FIG.

Since the squish flow S advances in the combustion chamber 32 along the wall surface of the combustion chamber on the cylinder head 2 side to the exhaust valve 16 side in FIG. 2, the squish flow S and the tumble flow T are ignited by the spark plug. Collide with each other in the vicinity of 12. In this engine 1, the ignition timing is set so that the ignition plug 12 ignites during the period when the air-fuel mixture is ejected from the squish area.

When the tumble flow T and the squish flow S collide with each other, the air-fuel mixture is dispersed as minute vortices (microturbulence), and the tumble flow T and the squish flow S are combined to form a gas. The flow lowers to the piston top portion 7a side. Therefore, the micro-turbulence promotes the growth of the flame kernel after ignition, and the flame spreads to the piston top 7a side, so that the combustion range is rapidly expanded. In this embodiment, the fuel gas is supplied in layers from the nozzle 4 to the vicinity of the spark plug 12, so that even if the total supply amount of the fuel gas is significantly smaller than the stoichiometric air-fuel ratio, ignition is assured. .
For this reason, even though lean combustion is performed in which the total amount of fuel gas supplied to the cylinder is significantly reduced compared to the theoretical air-fuel ratio, rapid combustion is possible and combustion is improved. It is possible to improve fuel efficiency.

As described above, in the gas fuel supply system according to this embodiment, the fuel passage 28 to which the gas fuel is supplied is supplied.
Is formed in the intake passage wall of the cylinder head 2, and the fuel injection port at the downstream end of the fuel passage 28, that is, the opening at the tip of the nozzle 4 is opened near the upstream side of the intake valve 15 in the intake passage 5, The fuel gas supplied from the fuel injection port into the intake passage 5 is sucked into the cylinder in a layered state so as not to be widely dispersed as if riding on the intake air flowing near the intake valve.

Therefore, the fuel gas can be supplied to the vicinity of the spark plug 12 in a layered manner so as to be relatively rich. The fuel injection port at the downstream end of the fuel passage 28 can be formed on the hole wall surface of the intake port 13 without using the nozzle 4, but by using the nozzle 4, the degree of freedom of the position where the gas injection port is provided is increased. Higher, intake outlet 21
Can be provided close to.

Further, the downstream end of the fuel passage 28 is formed by the nozzle 4 made of a pipe so as to face the inside of the intake passage 5, and the fuel injection port is connected to the portion near the spark plug 12 in the intake passage. Since the opening is made so as to be directed to the downstream side of the flow direction, the fuel gas flows in the same direction as the intake air without countering the intake air, flows into the cylinder, and is collected in the vicinity of the spark plug 12.

Further, the downstream end of the fuel passage 28 is formed by the nozzle 4 so as to face the inside of the intake passage 5, and the fuel injection port is formed between the intake valve 15 and the valve seat by opening the intake valve 15. The fuel gas does not disturb the flow direction of the intake valve 15 because it is opened so as to be directed to the gap, and the fuel gas is retained until it flows out of the fuel injection port and flows in layers into the cylinder. To be done. For this reason, stratification of the fuel gas becomes more remarkable.

In addition, the engine 1 according to this embodiment
, The kinetic energy of the air-fuel mixture is attenuated by the collision of the tumble flow T and the squish flow S. Therefore, the state of the air-fuel mixture after the collision does not change significantly even if the rotation speed or the load of the engine 1 changes. Therefore, the phenomenon of rapid combustion as described above similarly occurs over a wide operating range, and combustion can be improved over substantially the entire engine operating range.

Furthermore, the flow of the air-fuel mixture in the cylinder (flow downward in the recess 26 of the piston top 7a)
Since the ignition continues even after ignition, the unburned gas is continuously supplied to the initial combustion gas portion grown near the top portion 7a of the piston 7. For this reason, the initial combustion gas diffuses while being stirred by the unburned gas and is not held at a high temperature, so that it is possible to suppress the generation of Nox. It should be noted that even when the EGR amount is increased, the same operation as described above is performed, and it is possible to improve fuel efficiency and reduce Nox.

Furthermore, the collision of the tumble flow T and the squish flow S attenuates the kinetic energy of the mixed air flow, so that the electrodes 12a and 12b of the spark plug 12 are attenuated.
Since the air-fuel mixture does not flow at a high speed in the gap (see FIG. 2), ignition is stabilized and the ignition voltage does not have to be increased, so that the existing ignition device can be used.

In this embodiment, the intake port 1
3 to the side opposite to the exhaust valve 16 in the cylinder to generate a so-called reverse tumble flow in the cylinder,
Space where squish flow S is generated (squish area)
Is formed on the side of the intake valve 15 which is relatively low in temperature, knocking is less likely to occur than when the squish area is formed on the side of the exhaust valve 16. Further, since the opening (gas injection port) of the tip of the nozzle 4 is directed in the direction opposite to the exhaust valve 16 with the center of the combustion chamber as a reference, the fuel gas is also supplied to the low temperature portion, and knocking is further difficult to occur. Become.

Further, since the injector 3 has a plurality of fuel injection ports 27 and the nozzles 4 corresponding to the respective fuel injection ports 27 are provided, one injector 3 supplies fuel gas to a plurality of intake passages 5. Can be supplied.

In addition, since the engine 1 is provided with a plurality of intake valves 15 for each cylinder and an opening (gas injection port) at the tip of the nozzle 4 is provided for each intake valve 15, a plurality of intake valves are provided in the cylinder. The fuel gas can be supplied from each of the outlets 21, and the degree of freedom of the position for supplying the fuel gas is improved.

Further, the downstream end portion of the intake port 13 is provided with the inclined portion 23 which gradually extends toward the opposite side to the exhaust valve 16 toward the downstream side, so that the intake air flows so that a reverse tumble flow is formed. Since the direction is regulated, the intake resistance is reduced and the number of parts can be reduced as compared with the case where a member for changing the flow direction of intake air is provided in the intake port 13.

(Second Embodiment) In order to generate a tumble flow, the guide member shown in FIGS. 10 to 15 can be attached to the intake port. 10 is a cross-sectional view of an engine provided with a guide member, FIG. 11 is an enlarged cross-sectional view of a main portion of FIG. 10, and FIG. 12 is XII-X in FIG.
II sectional view, FIG. 13 is a diagram showing the guide member, the same (a)
Is a cross-sectional view in the state where it is assembled to the intake port, the same figure (b)
Is a side view, and in (b), the breakage position in (a) is indicated by line AA. FIG. 13C shows (a)
A sectional view taken along the line C-C in the figure, (d) shows a free state before mounting, and (b) shows a state in which the diameter is reduced at the time of mounting. 14 is an exploded perspective view of the guide member shown in FIG. 13, FIG. 15 is a view showing another example of the guide member, FIG. 14 (a) is a plan view, FIG. 15 (b) is a side view, and FIG. 6C is a cross-sectional view taken along the line CC in FIG. 7A, and FIG. 8D is a plan view showing a state in which the diameter is reduced at the time of mounting. In these figures, FIG.
The same or equivalent members as those described with reference to FIG. 9 are designated by the same reference numerals, and detailed description thereof will be appropriately omitted.

The engine 1 according to this embodiment is shown in FIG.
As shown in FIG. 0, the intake port 13 has a guide member 4 which will be described later.
1 has the same configuration as the engine 1 shown in the first embodiment except that the engine 1 is provided. The guide member 4
As shown in FIGS. 13 and 14, 1 comprises a C-shaped fixing ring 42 and a shroud 43 welded to the ring 42.

The ring 42 is made of a spring material and is formed so that it can be expanded in diameter and engaged with a concave groove 44 (see FIG. 11) formed at the downstream end of the intake port 13 by its own elastic force. ing. Also, at both ends of this ring 42,
A hook 45 for hanging a tool (not shown) is integrally formed.

The shroud 43 includes a support plate 46 curved along the inner peripheral surface of the ring 42 in an arc shape in a plan view, and a fan-shaped shroud main body 47 integrally formed with the support plate 46. It is composed by.
The support plate 46 is formed with an opening 48 through which the hook 45 of the ring 42 is inserted.
One end of the ring 42 is welded to the ring 42 while being overlapped with the inner peripheral portion of the ring 42 with the hook 45 inserted therethrough. Support plate 46
The welding range of the ring 42 is indicated by the symbol W in FIG.

The shroud 43 is inclined so as to gradually extend downward (downstream of the intake air flow) from the support plate 46 toward the center of the ring 42, and is curved so as to form a part of a conical surface. . Further, the guide member 41 is provided for the intake valve 1 in which the lower end of the shroud 43 is closed.
It is arranged so as to face 5 with a clearance.

The guide member 41 thus formed is assembled to the intake port 13 before the intake valve 15 is assembled to the cylinder head 2. More specifically, first, as shown in FIG. 13 (d), the hook 45 of the ring 42 of the guide member 41 in the free state is pinched with a tool such as pliers (not shown) to resist the elastic force of the ring 42. The diameter is reduced {see FIG. 13 (e)}, and the guide member 41 is inserted into the intake port 13 from the combustion chamber side. Then, the hook 45 is released while the ring 42 is engaged with the groove 44 of the intake port 13. At this time, the guide member 41 is positioned so that the shroud 43 is located on the exhaust valve 16 side. By releasing the tool, the ring 42 expands in diameter by its own elastic force and is fixed to the intake port 13 (cylinder head 2).

The guide member 41 shown in FIGS. 10 to 14 is formed so that the hook 45 of the ring 42 is positioned above the shroud 43.
It can also be formed as shown in FIG. In the guide member 41 shown in FIG. 15, the support plate 46 of the shroud 43 is welded to the inner peripheral portion 42a of the ring 42 that faces the hook 45.

The ring 42 of this guide member 41 is shown in FIG.
The free state shown by the solid line in (a) is reduced in diameter as shown in FIG. After mounting, this ring 42 is in a reduced diameter state from the free state as shown by the chain double-dashed line in the same figure (a), and is fixed to the intake port 13 by its own elastic force.

By forming the guide member 41 in this way, the hook 45 can be visually recognized from below, and therefore, when the hook 45 is pinched by pliers or the like, the hook 4 is not visible.
The position of 5 can be easily confirmed, and the assembling work becomes easy. The position where the guide member 41 is attached is shown in FIGS.
It is the same as the guide member 41 shown in FIG.

By providing the guide member 41 shown in FIGS. 10 to 15 in the intake port 13, the inclined portion 23 of the intake port 13 is substantially extended by the shroud 43 and hits the intake valve 15 and the intake outlet 21. It is possible to reduce the intake air flowing into the exhaust valve 16 side from the gap between and. As a result, the tumble flow T can be generated even more strongly.

Therefore, since the strength of the tumble flow T can be changed by the guide member 41, the tumble flow T is generated by the guide member 41 so that the tumble flow T has an optimum strength with respect to the generated squish flow S. This makes it possible to reliably generate microturbulence. Therefore, the combustion can be further improved.

(Third Embodiment) The guide member can be formed as shown in FIGS. 16 to 24. FIG.
17 is a sectional view of a part of the engine showing another example of the guide member, FIG. 17 is an enlarged sectional view of the guide member, and FIG. 18 is a view showing a portion near the combustion chamber of the engine as seen from the cylinder head side. FIG. 19 is a schematic view for explaining a tumble flow, FIG. 20 is a bottom view of a fuel gas supply nozzle,
21 is a sectional view taken along the line AA in FIG. 16, and FIG. 22 is FIG.
6 is a sectional view taken along line BB in FIG. 6, and FIG. 23 is C in FIG.
It is a -C line sectional view. FIG. 24 is an enlarged perspective view showing the guide member and the valve body of the intake valve.

In these figures, the same or equivalent members as those described with reference to FIGS. 1 to 15 are designated by the same reference numerals and detailed description thereof will be appropriately omitted. FIG.
24 to 24, the intake valve 15 is provided with a guide member 51. As shown in FIG. 24, the guide member 51 is made of a metal plate having a shape of a part of a cone, and is welded to the upper surface of the valve body 15b of the intake valve 15.

The shape of the guide member 51 will be described in more detail. As shown in FIG. 22, the guide member 51 is formed in a fan shape in plan view in which the width becomes wider as it goes upward, and as shown in FIG. In a side view, the intake valve 15 is inclined so as to be unevenly distributed outward in the radial direction as it goes upward. As shown in FIGS. 17 and 18, the position where the guide member 51 is attached to the intake valve 15 is one side portion of the intake valve 15 that is close to the exhaust valve 16, and as shown in FIG. Inner surface 51
The center of the arc of a is positioned so as to substantially coincide with the axis of the intake valve 15.

The height of the guide member 51 is as shown in FIG.
As shown in FIGS. 6 and 17, when the intake valve 15 is opened, the upper end portion faces the upstream side of the intake outlet 21 of the intake port 13,
As shown by the chain double-dashed line in FIG. 17, even if the intake valve 15 is closed, the upper end portion is set so as not to contact the inner wall surface of the intake port 13. In this embodiment, in order to prevent the intake valve 15 from rotating around the valve stem 15a and changing the position of the guide member 51 with respect to the intake port 13, as shown in FIG. The valve stem 15a is formed to have a quadrangular cross section, and the quadrangular cross section is slidably engaged with the valve stem guide 52 on the cylinder head 2 side.

The intake port 13 of the cylinder head 2 according to this embodiment is, as shown in FIG.
It is formed so as to extend obliquely from one side portion 2a toward the combustion chamber 32. The intake port 13 is formed so that the intake passage 5 is branched into branch passages 5a and 5b for each intake valve 15 on the way.

When the intake port 13 is formed in this way,
When the intake valve 15 is opened, the intake air is inertial and the combustion chamber 2
A large amount of the intake air hits the guide member 51, and the flow direction can be changed according to this embodiment. That is, since the intake air flows toward the direction opposite to the exhaust valve 16 by hitting the guide member 51, the engine 1 also has a reverse tumble in the cylinder as in the first and second embodiments. A flow occurs.

Since the intake port 13 is obliquely extended from the side portion of the cylinder head 2 as described above, the nozzle 4 for supplying the fuel gas is provided with the intake valve 15 from the one side portion 2a of the cylinder head 2. It is formed so as to extend to the vicinity. That is, the injector 3 is arranged in the intake passage 5, and the injector 3 is connected to the nozzle 4 having a tip opening near the upstream side of the intake valve 15.

The nozzle 4 according to this embodiment is shown in FIG.
And as shown in FIG. 21, the pipe 4 for each intake valve 15
a, 4a, and a pipe holder 4b to which the upstream ends of these pipes 4a are respectively connected.
As in the case of adopting the first and second embodiments, the pipe 4a has its downstream end located near the adjacent intake ports 13 in the intake port 13 and is downstream in the direction of intake air flow. The side is bent so that the opening of the tip is directed, and the upstream end extends inside the intake port 13 to the upstream side along the intake port upper wall 13a (see FIG. 16).

As shown in FIG. 20, the nozzle holder 4b has a fuel passage 4c communicating with the pipe 4a for each pipe. As shown in FIG. 16, the nozzle holder 4b is fixed to the intake port upper wall 13a. It is fixed by bolts 53. In the cylinder head 2 according to this embodiment, a through hole 54 for inserting a tool is formed in the lower wall 13b of the intake port so that the fixing bolt 53 can be easily attached and detached with a tool (not shown). In FIG. 16, the reference numeral 55 provided at the opening end of the through hole 54 indicates the through hole 5
4 is a plug member for closing 4.

The fuel passage 4c of the pipe holder 4b is
The fuel gas is injected from the fuel gas injector 3 mounted on the cylinder head 2 and opened at the upstream end of the pipe holder 4b. Even if the guide member 51 and the cylinder head 2 are configured as shown in this embodiment, the same effect as when the first and second embodiments are adopted can be obtained.

Further, in the engine 1, the injector 3 is arranged in the intake passage 5, and the injector 4 is connected to the nozzle 4 having a tip opening near the upstream side of the intake valve 15, and the opening of the nozzle 4 is connected to the gas. Since it is an injection port, the degree of freedom of the position where the gas injection port is provided is increased, and the gas injection port can be provided close to the intake port 12.

(Fourth Embodiment) When the intake port is formed so as to extend obliquely to the cylinder head, the fuel gas supply nozzle can be formed as shown in FIGS. 25 to 27. FIG. 25 is a cross-sectional view showing another example of the fuel gas supply nozzle, FIG. 26 is a plan view showing a configuration of a portion near the combustion chamber of the engine as seen from the cylinder head side, and FIG. 27 is A- in FIG. It is an A line sectional view.
In these figures, the same or equivalent members as those described with reference to FIGS. 1 to 24 are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate.

The fuel gas supply nozzle 4 shown in FIGS. 25 to 27 is composed of a pipe provided for each intake valve 15, and is fitted into the fuel gas supply through hole 61 of the cylinder head 2 from the intake port 13 side to intake air. It is arranged in the vicinity of the adjacent intake ports 13 in the port 13. Further, as shown in FIG. 25, these nozzles 4 are bent so that the opening at the tip is directed toward the downstream side in the intake air flowing direction.

The fuel gas supply through hole 61 is provided between the intake port 13 and the intake port 13 on one side 2a of the cylinder head 2 from above the inlet of the intake port 13.
A first gas hole 62 extending diagonally along a straight line, and a second gas hole extending to the intake port 13 of each intake valve 15 so as to branch from the downstream end of the first gas hole 62. 63 (see FIG. 27). The nozzle 4 is attached to the second gas hole 63. In addition, the upstream end of the first gas hole 62 is shown in FIG.
As shown in FIG. 6, the fuel gas supply injector 3 (not shown) is installed in the hole 29.

By forming the nozzle 4 in this way, the fuel gas injected from the nozzle 4 into the intake port 13 in the intake stroke is supplied to the intake valve 15 and the intake valve 15 as shown by a black arrow G in FIG. The gas flows in a diagonally downward direction in a direction opposite to the exhaust valve 16 in the cylinder through a gap between the outlet 21 and the outlet 21.

Further, by adopting the configuration shown in this embodiment, the fuel passage (fuel gas supply through hole 61) is provided with one portion from the upstream portion (upstream end portion of the first gas hole 62). Since the fuel gas can be supplied to the three intake ports 13, the structure becomes simple compared to the case where the fuel gas supply sources (injectors) are connected to the intake ports 13, respectively.
Further, by forming the downstream end of the fuel passage with the nozzle 4, the portion protruding into the intake port 13 is reduced, and an increase in intake resistance can be suppressed.

(Fifth Embodiment) The tumble flow generated in the cylinder may be a forward tumble flow as shown in FIGS. 28 to 34. 28 and 29 are sectional views of a gas fuel engine in which a guide member is provided in the intake valve to generate a forward tumble flow. FIG. 28 shows a state in the intake stroke, and FIG. 29 shows the piston positioned at the compression top dead center. The state is shown. FIG. 30 is a plan view showing the configuration of a portion near the combustion chamber of the engine as seen from the cylinder head side, FIG. 31 is a sectional view taken along the line AA in FIG. 28, and FIG.
6 is a view of an intake valve and an intake outlet in FIG. 33 is a cross-sectional view of a gas fuel engine that generates a forward tumble flow using a guide member attached to the intake port, and FIG. 34 is FIG.
FIG. 6 is a sectional view taken along line AA in FIG. In these figures,
Members that are the same as or equivalent to those described with reference to the above figures are given the same reference numerals and detailed description thereof is omitted as appropriate.

The intake port 13 of the engine 1 shown in FIGS. 28 to 32 is formed to extend obliquely from one side portion 2a of the cylinder head 2 toward the combustion chamber 32.
The intake port 13 is formed so that the intake passage 5 is branched into branch passages 5a and 5b for each intake valve 15 on the way. Therefore, most of the intake air that flows through the intake port 13 in the intake stroke is due to the inertia of the intake flow.
Flows obliquely into the cylinder toward the exhaust valve 16 side.

In the intake valve 15, in order to prevent intake air from flowing from the intake outlet 21 in the direction opposite to the exhaust valve 16,
A guide member 71 having a structure similar to that of the guide member 51 shown in the third embodiment is provided. The guide member 71 is formed of a metal plate having a shape of a part of a cone, and the intake valve 1
5 is welded to the upper surface of the valve body 15b.

The guide member 71 is formed in a fan shape in plan view (see FIG. 31) whose width becomes wider as it goes upward, and as shown in FIGS. The intake valve 15 is gradually inclined so as to be unevenly distributed outward in the radial direction. The position at which the guide member 71 is attached to the intake valve 15 is one side of the intake valve 15 opposite to the exhaust valve 16, and as shown in FIG. 31, the center of the arc of the inner surface 71a of the guide member 71 is the intake air. The valve 15 is positioned so as to substantially coincide with the axis of the valve 15.

The height of this guide member 71 is as shown in FIG.
As shown in FIGS. 8 and 29, when the intake valve 15 is opened, the upper end portion faces the upstream side of the intake outlet 21 of the intake port 13,
Even if the intake valve 15 is closed, the upper end portion is set so as not to contact the inner wall surface of the intake port 13. Also in this embodiment, in order to prevent the intake valve 15 provided with the guide member 71 from rotating, the valve stem 15a of the intake valve 15 is the same as in the case of adopting the third and fourth embodiments. Is slidably engaged with the valve stem guide 52.

In the engine 1, the intake air obliquely flows into the cylinder from the intake port 13 to generate a tumble flow, which is a swirling flow of the intake air, in the cylinder. As shown by the arrow T in FIG. 28, this tumble flow is a so-called forward tumble flow in which the swirling direction is opposite to that shown in the above-described first to fourth embodiments. Therefore, in the engine 1, the squish flow S and the tumble flow T are swirled in the combustion chamber 32 in the same direction at the end of the compression stroke.

In constructing the engine 1 so that the forward tumble flow is generated as described above, the pipe 4a of the fuel gas supply nozzle 4 is formed linearly so as to extend in the same direction as the intake air flow direction. There is. The nozzle 4 is arranged in a portion of the intake port 13 adjacent to the adjacent intake port 13, and as shown in FIG.
Is positioned so that the fuel gas is injected into the cylinder through the gap between the intake valve 15 and the intake outlet 21 in the open state. As in the case of adopting the first to fourth embodiments, the fuel gas is the first fuel supply stroke when the intake valve 15 is closed, and the second fuel gas when the intake valve 15 is open. The fuel is injected from the nozzle 4 in the fuel supply process.

The gas fuel engine 1 shown in FIG. 33 has a second
A guide member 8 equivalent to the guide member 41 shown in the above embodiment.
1 is provided in the intake port 13. Reference numeral 82 denotes a ring of the guide member 81, 83 denotes a shroud, 84 denotes hooks at both ends of the ring 82, and 85 denotes openings for inserting the hooks 84. The guide member 81 is fixed to the intake port 13 so that the shroud 83 sandwiches the intake valve 15 and is located on the side opposite to the exhaust valve 16. Even if the guide member 81 is provided in the intake port 13 as described above, the same effect as that obtained when the embodiment shown in FIGS.

[0082]

As described above, according to the present invention, the fuel gas supplied from the fuel injection port into the intake passage is not dispersed widely by riding on the intake air flowing near the intake valve. It is sucked in layers. Therefore, the fuel gas can be supplied to the vicinity of the spark plug in a layered manner so as to be relatively rich, so that lean combustion can be realized in the gas fuel engine and fuel consumption can be reduced in the gas fuel engine. it can.

According to the second or third aspect of the present invention, the degree of freedom of the position where the gas injection port is provided is increased, and the gas injection port can be provided close to the intake port. Therefore, the combustion gas can be provided without diffusing the fuel gas. To promote the stratification of the fuel gas.

According to the invention described in claim 4, the fuel gas flows in the same direction as the intake air without countering the intake air, flows into the cylinder, and is collected in the vicinity of the spark plug. Therefore, even after the shift to the compression stroke, the fuel gas is prevented from diffusing and is collected in the vicinity of the spark plug, so that the lean-burn can be performed by setting the air-fuel ratio to a leaner side. .

According to the fifth aspect of the invention, the fuel gas is not disturbed in its flowing direction by hitting the intake valve, and is maintained until it flows out of the fuel injection port and flows in a stratified form into the cylinder. . For this reason, the stratification of the fuel gas becomes more remarkable, and the combustion becomes stable.

According to the sixth aspect of the invention, since the fuel gas can be supplied to the two intake ports from one location on the upstream side of the gas fuel passage, the fuel gas supply source is connected to each intake port. Compared with the case, the structure is simpler and the cost can be reduced. Further, by forming the downstream end of the gas fuel passage by the pipe member, the portion protruding into the intake port can be reduced and the increase in intake resistance can be suppressed, so that the output can be increased.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a gas fuel engine equipped with a fuel supply device according to the present invention.

FIG. 2 is a cross-sectional view showing an enlarged part of the engine.

FIG. 3 is a plan view of a piston.

FIG. 4 is a plan view showing a configuration of a portion of the engine in the vicinity of a combustion chamber as viewed from the cylinder head side.

FIG. 5 is a bottom view showing the combustion chamber wall of the cylinder head.

FIG. 6 is a vertical cross-sectional view of a cylinder and a piston.

7 is a sectional view taken along line VII-VII in FIG.

FIG. 8 is a time chart showing opening / closing timings of intake / exhaust valves and fuel injection timings.

FIG. 9 is a sectional view showing another example of a piston.

FIG. 10 is a cross-sectional view of an engine provided with a guide member.

FIG. 11 is a cross-sectional view showing an enlarged main part in FIG.

12 is a sectional view taken along line XII-XII in FIG.

FIG. 13 is a diagram showing a guide member.

14 is an exploded perspective view of the guide member shown in FIG.

FIG. 15 is a diagram showing another example of the guide member.

FIG. 16 is a partial cross-sectional view of the engine showing another example of the guide member.

FIG. 17 is an enlarged sectional view showing a guide member.

FIG. 18 is a plan view showing the configuration of a portion of the engine in the vicinity of the combustion chamber as viewed from the cylinder head side.

FIG. 19 is a schematic diagram for explaining a tumble flow.

FIG. 20 is a bottom view of the fuel gas supply nozzle.

21 is a cross-sectional view taken along the line AA in FIG.

22 is a sectional view taken along line BB in FIG.

23 is a cross-sectional view taken along the line CC in FIG.

FIG. 24 is an enlarged perspective view showing a guide member and a valve body of an intake valve.

FIG. 25 is a cross-sectional view showing another example of the fuel gas supply nozzle.

FIG. 26 is a plan view showing the configuration of a portion of the engine in the vicinity of the combustion chamber as viewed from the cylinder head side.

27 is a cross-sectional view taken along the line AA in FIG.

FIG. 28 is a cross-sectional view of a gas fuel engine.

FIG. 29 is a cross-sectional view of a gas fuel engine.

FIG. 30 is a plan view showing the configuration of a portion of the engine in the vicinity of the combustion chamber as viewed from the cylinder head side.

31 is a cross-sectional view taken along the line AA in FIG. 28.

32 is a view on arrow B of the intake valve and the intake outlet in FIG. 28. FIG.

FIG. 33 is a cross-sectional view of a gas fuel engine that generates a forward tumble flow using a guide member attached to an intake port.

34 is a cross-sectional view taken along the line AA in FIG.

[Explanation of symbols]

1 ... Engine, 2 ... Cylinder head, 4 ... Nozzle, 5 ...
Intake passage, 7 ... Piston, 12 ... Spark plug, 13 ... Intake port, 15 ... Intake valve, T ... Tumble flow, S ... Squish flow.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoki Onda             Yamaha Motor, 2500 Shinkai, Iwata, Shizuoka Prefecture             Within the corporation F term (reference) 3G023 AA02 AA05 AB01 AC02 AC07                       AD02 AD05 AD07 AD08 AG01                       AG02                 3G024 AA04 AA05 AA09 BA29 DA01                       DA06 DA10 DA28 FA00

Claims (6)

[Claims] 1. A fuel supply device for a gas fuel engine for supplying gas fuel into an intake passage, comprising an injector for injecting the gas fuel, and a fuel injection port to which the gas fuel is supplied from the injector of an intake valve in the intake passage. A fuel supply device for a gas fuel engine opened near the upstream side. 2. The fuel supply device for a gas fuel engine according to claim 1, wherein the gas fuel passage for guiding the fuel gas from the injector to the fuel injection port of the intake passage has an upstream end connected to the injector and a downstream end. A fuel supply device for a gas fuel engine, the portion of which is formed by a pipe member facing the inside of the intake passage, and an opening at a downstream end of the pipe member serves as a fuel injection port. 3. The fuel supply device for a gas fuel engine according to claim 1, wherein a gas fuel passage for guiding the fuel gas from the injector to the fuel injection port of the intake passage is formed in a wall of the intake passage of the cylinder head. A pipe member connected to the downstream end of the through hole and facing the intake passage,
A fuel supply device for a gas fuel engine, in which an opening at the downstream end of the pipe member serves as a fuel injection port. 4. The fuel supply device for a gas fuel engine according to claim 2 or 3, wherein the fuel injection port is directed to a part in the intake passage, which is close to the spark plug, in a downstream side in a flow direction of intake air. A fuel supply device for a gas fuel engine, which is opened in the. 5. The fuel supply device for a gas fuel engine according to claim 2 or 3, wherein the fuel injection port is directed to a gap formed between the intake valve and the valve seat by opening the intake valve. A fuel supply device for a gas fuel engine, which is opened in the. 6. A fuel supply system for a gas fuel engine according to claim 1, wherein:
An upstream portion of the gas fuel passage is formed between two intake ports provided for each cylinder, and a downstream portion of this gas fuel passage is branched into a forked shape from the upstream portion and opened to each intake port. Gas fuel engine fuel supply system.