JPH09287541A - Fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small fuel injection device having excellent mounting performance on a cylinder head. SOLUTION: A fuel passage 19c, fuel supply valve means (a valve member 35, a seat member 34 and a spring 40), a mixing chamber 60 and fuel injection valve means (a rod 26, a movable core 27 and a spring 29) are collectively arranged in a small diametral cylindrical space inside the diametral directions of first and second coils 13, 12 arranged coaxially in series, and an air port 21d through which an air passage formed in a cylinder head and the mixing chamber 60 are communicated with each other is arranged in a fuel injection nozzle 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device, and more particularly to a fuel injection device for injecting fuel directly into a combustion chamber of an engine.

[0002]

2. Description of the Related Art As a conventional fuel injection device, for example,
JP-A-1-280673 and JP-A-1-28565
No. 8 discloses a technique disclosed in Japanese Patent Publication No. In the former fuel injection device, a fuel injection valve and a one-way valve that is opened and closed by the pressure of pressurized air are installed in the cylinder head of the engine, and the fuel supplied by the fuel injection valve is operated by the one-way valve by pressurized air. It is supplied to the combustion chamber via the. Further, in the latter fuel injection device, a fuel injection valve and a fuel adjustment valve are installed adjacent to each other in the cylinder head, and a fuel introduction passage for introducing fuel from the fuel adjustment valve into the nozzle portion of the fuel injection valve in the cylinder head. An air introducing passage for guiding the pressurized air to the nozzle portion is provided, and the fuel is injected together with the pressurized air from the nozzle portion to the combustion chamber via the poppet valve provided in the nozzle portion.

[0003]

In the conventional fuel injection device described above, the former one is provided with a recess in the cylinder head which communicates with the combustion chamber, and a one-way valve is arranged in the communication part of the recess with the combustion chamber. In addition, a fuel injection valve is provided in the recess, and pressurized air is supplied to the recess via a distribution valve so that air and fuel are mixed in the recess and injected into the combustion chamber from the one-way valve. It Further, in the latter, as described above, the fuel injection valve, the fuel control valve, the fuel introduction passage, and the air introduction passage are provided on the cylinder head.

By the way, in recent years, four valves per cylinder have become the mainstream, and intake and exhaust valves and spark plugs are densely arranged in a limited bore space on the cylinder head. In order to inject the fuel directly into the combustion chamber, the space saving is a major issue in disposing the fuel injection device in the cylinder head.

However, in the former case of the above-mentioned conventional fuel injection device, the fuel-air mixing chamber is provided in the cylinder head, and the fuel injection valve is accommodated in the mixing chamber. In the latter case, the fuel injection valve and Since the fuel adjusting valve and the like are individually arranged on the cylinder head, a large mounting space is required for mounting the fuel injection device, and the above-mentioned problems are not satisfied.

The present invention has been made in view of the above situation, and an object thereof is to provide a small-sized fuel injection device excellent in mountability on a cylinder head.

[0007]

Means for Solving the Problems The technical means of the present invention taken to solve the above-mentioned problems is to provide the fuel injection device,
A housing, a cylindrical first and second coil coaxially arranged in series in the housing, and a cylindrical shape, one end of which is fixed to the housing on the side of the second coil, and the other end A fuel injection nozzle having the other end attached to the cylinder head or the intake pipe so that the formed injection port is opened in the combustion chamber or the intake pipe formed in the cylinder head of the engine; An air port formed in the intake pipe and formed in an outer peripheral portion of the fuel injection nozzle so as to constantly communicate an air passage to which pressurized air is always supplied with a mixing chamber in the fuel injection nozzle; A fuel passage, which is formed on the side of the first coil of the housing and is always supplied with fuel, and coaxially arranged radially inward of the first coil and the second coil,
Fuel supply valve means that moves in the axial direction according to the magnetic flux generated when the first coil is excited to open and close communication between the fuel passage and the mixing chamber, and is coaxially arranged radially inward of the second coil. Fuel injection valve means for axially extending into the fuel injection nozzle, axially moving in accordance with a magnetic flux generated when the second coil is excited, and opening / closing communication between the mixing chamber and the combustion chamber or the intake pipe. It is to be configured to include and.

According to the above means, the fuel passage, the fuel supply valve means, the mixing chamber, and the fuel injection valve means are provided in the small-diameter cylindrical space radially inward of the first and second coils coaxially arranged in series. Are collectively arranged, so that the fuel injection device is downsized,
In particular, the diameter can be reduced. Therefore, the cylinder head can be mounted in a small space.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a fuel injection device according to the present invention will be described below with reference to the drawings.

1 to 3, the fuel injection device 10 is shown.
Has a cylindrical housing 11, and in the housing 11, a resin bobbin 14 in which a first coil 13 and a second coil 12 are coaxially wound in series in series is arranged. A resin-made covering member 15 is closely formed on the outer periphery of the first and second coils 13 and 12.
A connector 70 for supplying a current to the coils 12 and 13 is embedded in one end of the coil 5. A cylindrical first core 19 made of a magnetic material is provided at one end on the right side of the housing 11 in the figure.
However, the flange portion 19a is fixed to the housing 11 by caulking. One end side of the bobbin 14 is airtightly contacted to the left side surface of the flange portion 19a in the figure through an O-ring 20.

On the other end side of the housing 11 on the left side in the drawing,
The fuel injection nozzle 21 has a flange portion 21a at the right end in the figure.
Is caulked and fixed to the housing 11. The illustrated left end surface of the bobbin 14 is airtightly contacted to the illustrated right end surface of the flange portion 21a via an O-ring 22. Further, in the housing 11, the first and second bobbins 14 are provided.
Flange portion 25a that is hermetically sandwiched between coil housing portions
The cylindrical second core 25 made of a magnetic material having is disposed. The cylindrical portion 25b of the second core 25 that extends in the axial direction toward the second coil 12 side is fitted into the inner hole of the first bobbin 14.

The fuel injection nozzle 21 has a stepped inner hole 21b extending in the axial direction, and a rod 26 having a valve portion 26a at one end is slidably disposed in the inner hole 21b. . As shown in FIG. 1, the fuel injection nozzle 21 is hermetically fitted in a mounting hole formed in the cylinder head 81, and a plurality of injection ports formed at the tip of the fuel injection nozzle 21 are opened in the combustion chamber 83. are doing. In FIG. 1, 80 is a cylinder block on which a cylinder head 81 is fixed, and 82 is a piston slidably fitted in a cylinder formed in the cylinder block 80. In FIG. 3, the other end of the injection port whose one end is opened to the combustion chamber 83 is opened inside the inner hole 21b of the fuel injection nozzle 21, and a conical surface valve seat is formed around the other end opening of this injection port. Is formed, and the valve portion 26a of the rod 26 can be seated on this valve seat. The other end of the rod 26 is fixed to an inner hole 27a of a movable core 27 made of a magnetic material that is disposed in the inner hole of the bobbin 14 so as to be movable in the axial direction. It is movable in the axial direction as a unit. As a result, when the second coil 12 is excited, the second core 25, the movable core 27, the fuel injection nozzle 2
1 and the housing 11 form a magnetic circuit around the second coil 12. A cylindrical sleeve is fitted in the inner hole of the bobbin 14 radially inward of the second coil 12, and the left end portion of the cylindrical sleeve in the drawing is projected from the flange portion 21a of the fuel injection nozzle 21 to the right side in the drawing. The protruding portion is fitted in an airtight manner via the O-ring 23.
The flange portion at the right end of the movable core 27 in the figure is guided in the cylindrical sleeve.

The rod 26 has a stepped shape. One end of the rod 26 is communicated with the inner hole 27b of the movable core 27 on the large diameter side and the other end is branched to the conical stepped portion of the rod 26. A communication hole 26c that opens is formed. still,
In FIG. 3, FIG. A on the left side of the conical step portion is a left side view of the conical step portion. The rod 26 and the movable core 27 are
A valve portion 26a is provided by a spring 29 stretched between the right end of the flange portion 27a of the movable core 27 in the drawing and a seat member 34 that is airtightly fitted in the inner hole 25c of the cylindrical portion 25b of the second core 25. Is always urged to sit on the valve seat.

The first core 19 has a cylindrical portion 19b extending into the inner hole of the second bobbin 15, and an O-ring 30 is fitted on the outer periphery of the cylindrical portion 19b. The sleeve 31 is airtightly fitted. The illustrated left end portion of the sleeve 31 is a flange portion 25 a of the second core 25.
It is fixed in a recess 25e formed inwardly in the radial direction. Inner hole 25c of the cylindrical portion 25b opening to the recess 25e
Sheet member 3 having an orifice 34a at the opening of
4 is fixed airtightly. An annular valve seat on which a valve member 35 described later can be seated is formed at the right end of the seat member 34 in the figure. The sheet member 34 is formed at the left end in the figure, and a cylindrical portion having an inner hole 34b communicating with the orifice 34a is airtightly fitted in the inner hole 25c of the second core 25. A small diameter portion is formed on the outer circumference on the side. A groove is formed on the inner circumference of the inner hole 25c of the second core 25 at the same position as the small diameter portion in the axial direction, and the cylindrical member 41 is fitted and fixed in the groove.
The above-described spring 29 is stretched in an annular gap formed between the cylindrical member 41 and the left end small diameter portion of the seat member 34 in the drawing. A stepped inner hole 19c penetrating in the axial direction is formed in the axis of the first core 19, and constitutes the fuel passage of the present invention. When the first coil 13 is excited, the housing 11, the second core 25,
By the sheet member 34 and the first core 19, the first coil 13
A magnetic circuit is formed around it.

A valve member 35 made of a magnetic material is axially movable between the tip end of the cylindrical portion 19b of the first core 19 and the seat member 34. The valve member 35 has a plurality of communicating holes 35a extending in the axial direction on the outer peripheral portion thereof, and the outer peripheral surface thereof is guided by the inner surface of the sleeve 31. A small-diameter portion is formed in a portion of the cylindrical portion 19b closer to the tip end than a portion where the O-ring 30 is fitted, and an annular passage 36 is formed between the sleeve portion 31 and the sleeve 31. The annular passage 36 is communicated with the inner hole 19c by radial communication holes 37 formed in the small diameter portion of the cylindrical portion 19b.
Further, the inner hole 19c on the tip side of the small diameter portion of the cylindrical portion 19b has a large diameter, and the large diameter portion has a cylindrical stopper member 38.
Has been fixed. The stopper member 38 serves as the valve member 3
5, the end surface facing 5 is the valve member 35 of the small diameter portion of the cylindrical portion 19b.
It is formed so as to pop out from the end surface facing
Thereby, when the valve member 35 moves to the right side in the drawing so as to be separated from the valve seat of the seat member 34, a gap is maintained between the valve member 35 and the cylindrical portion 19b.

A plug 39 is fixed to the inner hole 19c of the first core 19 located coaxially with the fuel injection nozzle 21 from the fuel introduction port 32 side at the left end in the figure, which is connected to a fuel delivery pipe (not shown). The valve member 35 is always provided between the tip of the plug 39 and the valve member 35.
A spring 40 for urging the side to be seated on the valve seat is stretched. As a result, the fuel introduced from the fuel introduction port into the inner hole 19c always reaches around the valve seat of the seat member 34.

As described above, in this embodiment, the fuel injection nozzle 21 is hermetically fitted in the mounting hole formed in the cylinder head 81 above the combustion chamber, as shown in FIG. It The cylinder head 81 has a structure shown in FIGS.
As shown in FIG. 3, an air passage 81a extending in the axial direction is formed, and the air passage 81a penetrates (encloses) each mounting hole (in FIG. 2, the cylinder head of a four-cylinder engine is shown). There is. This air passage 81a is
One end is closed, and the other end is constantly supplied with pressurized air from an air pump 90 via a regulator 91. still,
The regulator 91 has a function of keeping the pressure of the pressurized air from the air pump 90 constant. This air passage 81
As shown in FIGS. 1 and 3, the cylinder portion of the fuel injection nozzle 21 surrounded by a has a plurality of air ports 21 in the radial direction.
d is formed, and the mixing chamber 60 is always formed in the inner hole 21b of the fuel injection nozzle 21 through the air port 21d between the bottom of the inner hole and the conical step portion of the rod 26.
Pressurized air is supplied inside.

As described above, in this embodiment,
First and second coils 13, 1 arranged coaxially in series
2, a fuel passage 19c, fuel supply valve means (valve member 35, seat member 34, spring 40), mixing chamber 60, and fuel injection valve means (rod 2)
6, the movable core 27, and the spring 29) are centrally arranged to reduce the size of the fuel injection device, in particular, to reduce its diameter.

The operation of this embodiment having the above configuration will be described.

1 to 3, the compressed air is always introduced into the mixing chamber 60 in the fuel injection nozzle 21 via the air passage 81a and the air port 21d. Therefore, the rod 26 from the mixing chamber 60 is introduced. Through the communication hole 26c, the inner hole 27b of the movable core 27, the inner hole 34c of the cylindrical portion of the seat member 34, and the orifice 34a.
The pressurized air is constantly introduced to the inner peripheral portion of the annular valve seat of the second core 2 and the right end of the fuel injection nozzle 26 in the drawing.
Pressurized air is constantly introduced to the space formed between the left end of FIG. 5 and the sleeve. In addition, the valve member 3 is provided through the inner hole 19c of the first core 19, the communication hole 37, and the annular passage 36.
Fuel is constantly introduced into the periphery of 5 (outer periphery of the annular valve seat of the seat member 34) at a pressure higher than the pressure of compressed air through the fuel introduction port at the right end of the inner hole 19c in the figure.

In this state, when the first coil 13 and the second coil 12 are not excited, the valve member 35 is seated on the valve seat of the seat member 34 by the spring 40, and the valve portion 26a of the rod 26 is attached to the fuel injection nozzle. The valve seat 21 is seated by a spring 29.

When the first coil 13 is excited, a magnetic circuit is formed around the coil 13 as described above, and the magnetic flux generated thereby causes the valve member 35 to separate from the seat member 34 against the spring 40. , Fuel is the orifice 34
a, and flows into the mixing chamber 60 through the inner hole 26c of the rod 26. Here, since the fuel passes through the orifice 34a and flows into the mixing chamber 60, if the pressure in the mixing chamber 60 is constant, the amount of the fuel flowing into the mixing chamber 60 is the valve member 35.
Is proportional to the time that is open.

Thereafter, the first coil 13 is demagnetized, the valve member 35 is again seated on the valve seat of the seat member 34, and the mixing chamber 6
When the pressure inside 0 is higher than the pressure inside the combustion chamber of the internal combustion engine (not shown), the second coil 12 is excited and the magnetic flux generated by the magnetic circuit formed around the second coil 12 causes the movable core 27 and the rod 26 to spring. When the valve portion 26a moves away from the valve seat of the nozzle 21 against 29, the air-fuel mixture in the mixing chamber 60 is injected into the combustion chamber 83. Then, the second coil 12 is demagnetized, and the valve portion 26
When a seats on the valve seat, the pressure in the mixing chamber 60 is maintained at that point.

[0024]

As described above, according to the present invention, the fuel passage, the fuel supply valve means, and the mixing are provided in the small-diameter cylindrical space radially inward of the first and second coils coaxially arranged in series. Since the chamber and the fuel injection valve means are collectively arranged, it is possible to reduce the size of the fuel injection device, particularly the diameter thereof. therefore,
It is possible to mount the cylinder head in a small space. Further, since the air port is provided in the radial direction from the axis of the fuel passage and the position of the air port and the fuel introduction port does not change even if the fuel injection valve is rotated, the fuel injection valve can be easily rotated. Therefore, the assembling property can be remarkably improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a mounted state of an embodiment of a fuel injection device according to the present invention.

FIG. 2 is a top view of the embodiment shown in FIG.

FIG. 3 is a cross-sectional view of the embodiment shown in FIG.

[Explanation of symbols]

 10 Fuel Injection Device 11 Housing 12 Second Coil 13 First Coil 19 First Core 19c Inner Hole (Fuel Passage) 21 Fuel Injection Nozzle 21d Air Port 26 Rod (Fuel Injection Valve Means) 34 Seat Member (Fuel Supply Valve Means) 35 Valve member (fuel supply valve means) 60 Mixing chamber 81 Cylinder head 81a Air passage

Claims (1)

[Claims] 1. A housing, cylindrical first and second coils coaxially arranged in series in the housing, and a cylindrical shape, and one end of which is fixed to the housing on the side of the second coil. And a fuel injection nozzle attached at the other end to the cylinder head or the intake pipe so that the injection port formed at the other end is opened to the combustion chamber or the intake pipe formed in the cylinder head of the engine. Formed in the cylinder head or the intake pipe and formed in the outer peripheral portion of the fuel injection nozzle so as to always communicate the air passage to which pressurized air is constantly supplied with the mixing chamber in the fuel injection nozzle. An air port and the first of the housing
A fuel passage, which is formed on the coil side and is always supplied with fuel, is arranged coaxially inward in the radial direction of the first coil and the second coil, and axially according to the magnetic flux generated when the first coil is excited. A fuel supply valve means that moves to the inside of the second coil to open and close the communication between the fuel passage and the mixing chamber, and is arranged coaxially inward of the second coil in the radial direction and extends in the fuel injection nozzle in the axial direction. A fuel injection device comprising a fuel injection valve means that moves in the axial direction according to a magnetic flux generated when the second coil is excited to open and close communication between the mixing chamber and the combustion chamber or the intake pipe.