JP2000230469A - Cylinder fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spray of a solid flat shape by forming a plurality of recessed passageways in an area between a position of a valve seat portion against which a valve member collides and an inlet portion of a fuel injection orifice whose cross section is an oval shape, while making fuel outlet portions of the recessed passageways to be open facing to each other inside the fuel injection orifice. SOLUTION: Recessed passageways 25 are provided in areas between a cylindrical fuel circulating member 22 and a seating surface 9, and an oval-shaped fuel injection orifice 8. Outlet portions of these recessed passageways 25 are made to be open facing to each other at an inlet portion of the oval-shaped fuel injection orifice 8. According to this construction, fuel flows through an axial passageway 23 and radial passageway 24 to reach a fuel sump chamber 26. It further moves toward the oval-shaped fuel injection orifice 8 via recessed passageways 25 in which a swirl faces each other. The fuel, which has moved past the radial passageways 24, collides with another charge of fuel at the inlet portion of the oval-shaped fuel injection orifice 8 as it flows through the opposing recessed passageways 25 downstream. It is then bent and diffuses as it moves further downstream. This makes the shape is of a spray into a solid form and makes its cross section flat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel (gasoline)
The present invention relates to an in-cylinder fuel injection device capable of generating a spray characteristic capable of stably burning a lean air-fuel mixture by directly injecting into a combustion chamber and burning.

[0002]

2. Description of the Related Art An in-cylinder fuel injection device for directly injecting fuel into a combustion chamber has been widely used, compared to an in-pipe fuel injection device for injecting fuel into an intake pipe of an engine.

The in-cylinder injection type internal combustion engine described in JP-A-6-146886 discloses a combustion chamber formed between an upper surface of a piston inserted into a cylinder and a lower surface of a cylinder head, and a central axis of the cylinder. An intake opening end that opens into the combustion chamber on one side of the reference surface, an intake port extending upward from the intake opening end, and an on-off valve formed on the cylinder head to be located on the other side of the reference surface. An exhaust port that communicates with the combustion chamber through the fuel chamber; and an electromagnetic fuel injection valve disposed on a side of the combustion chamber on the side of the intake port so that an injection port faces the combustion chamber. The intake air introduced into the combustion chamber by the intake port flows from the lower surface of the cylinder head on one side of the reference surface toward the upper surface of the piston along the central axis direction, and from the upper surface of the piston on the other side of the reference surface. Heading toward the bottom of the head It is configured to form a vortex,
In order to promote the formation of the longitudinal vortex, the intake flow center of the intake port is eccentric to one half in the axial direction, and the electromagnetic fuel injection valve is optimal for in-cylinder injection. The engine can be mounted in a state, and a strong tumble (longitudinal vortex) flow is formed in the combustion chamber so that the engine can be operated stably even in lean combustion.

On the other hand, FIG. 7 shows a main configuration diagram of a direct injection gasoline engine studied by the present inventors. Although details will be described later, the electromagnetic fuel injection valve attached to the direct injection gasoline engine has a 30 °
The injection hole is directed at a cavity (dent) provided on the piston upper surface. The intake air flow introduced from the intake valve portion is formed as a swirling flow flowing around the cavity to prevent the fuel spray injected from the electromagnetic fuel injection valve from adhering to the inner wall surface of the cylinder, and to form Leads to
The engine is configured to operate stably even in lean combustion.

[0005] This type of direct injection gasoline engine selectively uses homogeneous combustion and stratified combustion depending on the load. According to the authors' experimental analysis results, in homogeneous combustion, it is necessary to diffuse the spray throughout the combustion chamber to homogenize the air-fuel mixture. In the combustion, it was found that the spray angle was narrow and compact because it was necessary to prevent the mixture from being excessively dispersed and to guide the combustible mixture around the spark plug.

[0006]

As described above, the in-cylinder injection gasoline engine according to the present invention generally requires a widely dispersed spray during homogeneous combustion and a compact spray during stratified combustion. On the other hand, regarding the expansion of the stable combustion range, the spray behavior obtained from the previous experimental analysis can be summarized as follows. The duration of the combustible mixture is as long as possible.

[0007] It has been clarified that the shape of the spray that satisfies such characteristics should be a solid flat shape in which liquid droplets are relatively present inside. In the cited example described above, the design is devised in relation to the strong vertical vortex generated in the combustion chamber and the position of the injection port of the injection valve, and the relationship between the timing of fuel injection and the ignitability. Has no special considerations.

An object of the present invention is to provide an electromagnetic fuel injection valve for use in a direct injection gasoline engine, wherein the injection valve structure can realize a solid flat spray which can expand a stable combustion range during stratified combustion. Is to do.

[0009]

For this purpose, the in-cylinder fuel injection device of the present invention has a fuel passage through which fuel flows and a valve member for opening and closing the fuel passage.
The valve seat includes a cylindrical fuel flow member that allows passage of fuel upstream of a valve seat portion of the valve member, and a fuel injection hole that allows passage of fuel downstream of the valve seat portion. A plurality of recessed passages are formed between the position of the valve seat portion where the valve member collides and the entrance of the fuel injection hole whose section is elliptical, and the fuel outlet portion of the recessed passage is The fuel injection holes are provided so as to face each other.

Further, in the in-cylinder fuel injection device of the present invention, a fuel passage through which fuel flows is formed, a valve member for opening and closing the fuel passage, and an upstream side of a valve seat of the valve member. A cylindrical fuel flow member that allows the passage of fuel at
A fuel injection hole that allows passage of fuel downstream of the valve seat, wherein the position and cross section of the valve seat where the valve member collides with the valve member are elliptical. A plurality of concave passages are formed between the entrances of the injection holes,
The fuel inlet of the concave passage is disposed so as to face the outlet of the radial passage of the fuel passage member, and the outlet of the concave passage is provided so as to face open in the fuel injection hole. ing.

Further, in the in-cylinder fuel injection device of the present invention, a fuel passage through which fuel flows is formed, a valve member for opening and closing the fuel passage, and an upstream side of a valve seat portion of the valve member. And a fuel injection hole that allows the passage of fuel at the downstream side of the valve seat, and the valve member collides with the valve seat at the valve seat. A recess passage is formed between the position of the valve seat portion and the inlet of the fuel injection hole having an elliptical cross section, and the outlet of the recess passage is provided so as to face open in the fuel injection hole. The fuel arriving at the recess passage collides at the entrance of the fuel injection hole, and thereafter spreads downstream in the elliptical fuel injection hole.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view of an electromagnetic fuel injection valve 1 for an in-cylinder fuel injection device showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of a main part in which a valve portion is enlarged, and FIG. FIG. 4 is a diagram showing the recess passage, FIG. 4 is a cross-sectional view in the direction D of FIG. 3, showing the state of the recess passage and the flow of fuel, and FIG. The structure and operation will be described with reference to each drawing.

The electromagnetic fuel injection valve 1 injects fuel by opening and closing the seat in response to a duty ON-OFF signal calculated by the control unit. The magnetic circuit includes a core 2 including a bottomed cylindrical yoke 3, a plug 2 a for closing an open end of the yoke 3, and a columnar portion 2 b extending to the center of the yoke 3, and a plunger facing the core 2 with a gap therebetween. 4 In the center of the columnar part 2b, a movable part 4 comprising a plunger 4, a rod 5, and a valve 6
A is provided in the seat surface 9 on the upstream side of the elliptical fuel injection hole 8 that allows the passage of fuel formed in the nozzle member 7 by providing a hole for inserting and holding a spring 10 as a pressing elastic member. is there.

The upper end of the spring 10 is in contact with the lower end of a spring adjuster 11 inserted through the center of the core 2 for adjusting the set load. Columnar portion 2b of core 2
In order to prevent fuel from flowing out to the coil 14 side, a seal ring 12 that is mechanically fixed is provided between both sides of the gap portion facing the movable portion 4B side of the yoke 3 with the side.

The coil 14 for exciting the magnetic circuit is a bobbin 1
3 and its outer periphery is molded with a plastic material. Terminal 17 of coil assembly 15 composed of these
Are inserted into holes 16 provided in the flange of the core 2.
The terminal 17 is connected to a terminal of a control unit (not shown). A movable part 4 is provided at the bottom of the yoke 3.
A plunger receiving portion 18 for receiving A is opened,
A lower portion thereof is formed with a diameter larger than that of the plunger receiving portion 18, and a stopper 19 and a nozzle receiving portion 20 for receiving the nozzle member 7 penetrate to the tip of the yoke.

The movable part 4A is a plunger 4 made of a magnetic material.
And a valve body 6 having one end joined to the plunger 4 and a valve element 6 connected to the rod 5, and a hollow portion 5A is provided on the plunger 4 side of the rod 5 to allow fuel to pass therethrough.
The cavity 5A is provided with a fuel outlet 5B. The movable part 4A is such that the outer periphery of the plunger 4 is a seal ring 1
The valve body 6 joined to the other end of the cylindrical fuel flow member 22 is inserted into the hollow inner wall 21 of the nozzle member 7 while being guided in the axial direction by contact with the nozzle member 2. Each is guided by contacting the inner wall.

The nozzle member 7 has a cylindrical fuel flow member 22 that guides the valve body 6 with the inner wall 22a, and then the valve body 6
Is formed, and the sheet surface 9 is formed.
An oval fuel injection hole 8 is provided at the center of the fuel injection hole to allow the passage of fuel. The stroke of the movable part 4A (the amount of upward movement of the shaft) is determined by the receiving surface 5C of the neck of the rod 5 and the stopper 19.
It is determined by the size of the gap between them. A filter 27 is provided to prevent dust and foreign matter in fuel and pipes from entering the sheet.

Here, the structure of the cylindrical fuel flow member 22 and the concave passage 25 provided between the seat surface 9 and the elliptical fuel injection hole 8 according to the present invention, and the electromagnetic type using the fuel flow member 22 The spray characteristics of the fuel injection valve 1 will be described with reference to FIGS.

FIG. 2 is a longitudinal sectional view in which the valve portion is enlarged, FIG. 3 is a view for explaining the facing concave passage 25 according to the present invention, and FIG. 4 is a sectional view in the direction D in FIG. The positional relationship between the flow member 22 and the radial passages 24 and the state of fuel flowing through these passages are shown. The pressurized fuel is introduced from above the valve element 6, reaches the fuel reservoir 26 from the axial passage 23 and the radial passage 24, and further flows downstream through the facing concave passage 25 according to the present invention to form an elliptical shape. It goes to the fuel injection hole 8.

The solid arrows shown in FIG. 4 indicate this flow. As is apparent from FIG. 4, the entrance of the recess passage 25 faces the radial passage 24 of the fuel flow member 22. The outlet of the recess passage 25 is open to the inlet of the elliptical fuel injection hole 8. Radial passage 24
Is passed through the recess passage 2 facing the fuel reservoir 26.
5 flows downstream, it collides at the entrance of the elliptical fuel injection hole 8, and then the flow direction is bent and diffused downstream.

FIG. 5 shows the shape of the spray obtained by such a configuration, by depicting the spray behavior when injected into the combustion chamber from a visualization experiment. The shape of the spray is a solid structure relatively concentrated in the center, and the cross section is flattened by the diffusion flow after the collision. Such a spray does not protrude from the cavity of the piston and is dispersed without being concentrated in one place.

Referring back to FIG. 1, the operation of the fuel injection valve 1 according to the present invention will be described.

The fuel injection valve 1 operates the movable part 4A to open and close the valve seat surface 9 in response to an electrical ON-OFF signal supplied to the electromagnetic coil 14, thereby controlling fuel injection. When an electric signal is applied to the coil 14, a magnetic circuit is formed by the core 2, the yoke 3, and the plunger 4, and the plunger 4 is attracted to the core 2. When the plunger 4 moves, the valve body 6 integral with the plunger 4 also moves and separates from the seat surface 9 of the valve seat of the nozzle member 7 to open the fuel injection hole 8.

The fuel is pressurized and adjusted via a fuel pump or a regulator for adjusting the fuel pressure (not shown), flows into the fuel injection valve 1 from the filter 27, and passes through the lower passage of the coil assembly 15 and the outer periphery of the plunger 4. Part, stopper 1
9 and rod 5, axial passage 2 of fuel flow member 22
3 and the radial passage 24 to the elliptical fuel injection hole 8 via the facing concave passage 25 according to the invention downstream.

FIG. 6 shows a second embodiment of the present invention. FIG. 1A shows an embodiment in which the fuel injection hole 30 has a non-axisymmetric elliptical shape, and FIG.
Each shows an embodiment in which a fuel injection hole 31 having an enlarged chamber 32 in which the end of the ellipse is enlarged is provided. In this embodiment (a), the fuel colliding through the concave passage 25 is injected with an asymmetrical passage with varying degrees of left and right diffusion.
As a result, the spray becomes a solid flat shape offset from the central axis of the injection valve.

Further, in the embodiment (b), the fuel colliding through the concave passage 25 is further promoted by the expansion chamber 32 and becomes a solid flat shape having a relatively high degree of dispersion. The other configuration is the same as that of the first embodiment. In this embodiment, the same operation and effect as those of the first embodiment are obtained.

Next, the configuration and combustion operation of the in-cylinder direct-injection gasoline engine 60 used by the authors for the study will be described with reference to FIG. The figure shows an enlarged view of a main part around the engine. Reference numeral 61 denotes an intake air amount control device having a built-in throttle valve, and 62 denotes an intake air amount control device.
It is an intake manifold to which is attached. Reference numeral 63 denotes a cylinder head, which has an intake valve 64 on the intake manifold 62 side, a spark plug 65 in the center, and an exhaust valve 66 on the side opposite to the intake valve 64.
Is provided.

The electromagnetic fuel injection valve 1 for the in-cylinder fuel injection device according to the present invention is mounted at an angle of about 30 ° to 45 ° near the joint of the cylinder head 63 with the intake manifold 62. The injection direction is arranged so as to be directed to a cavity 69A provided in a piston 69 in the combustion chamber 67. 68 is a cylinder. In the drawing, white arrows indicate the flow of intake air, and hatched arrows indicate the flow of exhaust gas.

In this gasoline engine, the combustion state is controlled by the load as follows. At partial load, stratified charge combustion is performed by late-stage in-cylinder injection (compression stroke injection), and at high load, homogeneous combustion is performed by the in-cylinder injection (intake stroke injection). That is, in the stratified charge combustion, a layer of a rich air-fuel mixture is formed in the vicinity of the ignition plug 65 to realize stable combustion of a lean air-fuel mixture. In the homogeneous combustion, the mixture is homogenized in the entire combustion chamber, thereby realizing the premixed lean combustion.

These aim at realizing both low fuel consumption and high output at the same time, and the spray injected from the electromagnetic fuel injection valve 1 for the in-cylinder fuel injection device is optimized for the intake and compression strokes. It is generated in accordance with the appropriate injection timing. The injection signal is issued by a control unit (not shown) based on the operation information of the engine.

The figure shows the state of fuel injection during the compression stroke, in which the spray fuel is dispersed toward the ignition plug 65 in the combustion chamber 67, and the small-diameter droplets having a low velocity are formed in the combustion chamber 67. Immediate mixing with air is promoted. Thereafter, the air-fuel mixture is further compressed and stably ignited by the spark plug 65, thereby realizing stable lean combustion in which the amount of emission of unburned gas is suppressed.

[0032]

As described above, according to the present invention,
A plurality of concave passages are formed between the position of the valve seat where the valve member collides and the entrance of the fuel injection hole having an elliptical cross section, and a fuel outlet portion of the concave passage. Are provided so as to face each other in the fuel injection hole, and are arranged such that the fuel inlet of the concave passage faces the outlet of the radial passage of the upstream fuel passage member, The fuel that reaches the concave passage collides at the entrance of the fuel injection hole, and then flows downstream while diffusing in the elliptical fuel injection hole, so that it can be optimally dispersed in the piston cavity. An actual flat spray is produced. When such spray is supplied to the combustion chamber of a direct injection gasoline engine, an appropriate air-fuel mixture toward the ignition plug is generated, and stable ignition and combustion can be performed, reducing the emission of unburned gas components and improving fuel efficiency. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electromagnetic fuel injection valve for an in-cylinder fuel injection device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the vicinity of a tip portion of the fuel injection valve of the present invention.

FIG. 3 is a view showing a facing recess passage provided in the valve member.

FIG. 4 is a view showing a state of a recess passage and a fuel flow in a sectional view taken in a direction D in FIG. 3;

FIG. 5 is a diagram depicting a spray behavior in a cylinder.

FIG. 6 is a cross-sectional view of the vicinity of a distal end portion of a fuel injection valve according to a second embodiment of the present invention.

FIG. 7 is an enlarged view of a main part of a direct injection gasoline engine incorporating the fuel injection valve of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electromagnetic fuel injection valve, 6 ... Valve body, 8 ... Fuel injection hole, 2
2: fuel flow member, 23: axial passage, 24: radial passage, 25: concave passage, 26: fuel swirl chamber.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Yamamon 502, Kandate-cho, Tsuchiura-shi, Ibaraki Pref.Mechanical Research Laboratory, Inc. Inside the Machinery Research Laboratory (72) Inventor Kiyoshi Amaba 502 Kandachi-cho, Tsuchiura-city, Ibaraki Pref. Inside the Machine Research Laboratory, Hitachi Ltd. Internal F-term (reference) 3G066 AA02 AA05 AB02 AD12 BA14 BA17 BA26 CC06U CC10 CC14 CC20 CC34 CC37 CC48 CE22

Claims (3)

[Claims] 1. An electromagnetic fuel injection valve for directly injecting fuel into a combustion chamber of an internal combustion engine, wherein a valve member for forming a fuel passage through which fuel flows and opening and closing the fuel passage is provided. The valve seat includes a cylindrical fuel flow member that allows passage of fuel upstream of a valve seat portion of the valve member, and a fuel injection hole that allows passage of fuel downstream of the valve seat portion. A plurality of concave passages are formed between the position of the valve seat where the valve member collides and the inlet of the fuel injection hole having an elliptical cross section, and a fuel outlet of the concave passage is formed. An in-cylinder fuel injection device, which is provided so as to face each other in the fuel injection hole. 2. An electromagnetic fuel injection valve for directly injecting fuel into a combustion chamber of an internal combustion engine, the valve including a fuel passage through which fuel flows, and a valve member for opening and closing the fuel passage. The valve seat includes a cylindrical fuel flow member that allows passage of fuel upstream of a valve seat portion of the valve member, and a fuel injection hole that allows passage of fuel downstream of the valve seat portion. A plurality of concave passages are formed between the position of the valve seat where the valve member collides and the entrance of the fuel injection hole having an elliptical cross section, and the fuel entrance of the concave passage is A cylinder disposed so as to face an outlet of the radial passage of the fuel passage member, and an outlet of the concave passage is provided so as to face open in the fuel injection hole; Internal fuel injection device. 3. An electromagnetic fuel injection valve for directly injecting fuel into a combustion chamber of an internal combustion engine, wherein a valve member for forming a fuel passage through which fuel flows and opening and closing the fuel passage is provided. The valve seat includes a cylindrical fuel flow member that allows passage of fuel upstream of a valve seat portion of the valve member, and a fuel injection hole that allows passage of fuel downstream of the valve seat portion. A plurality of concave passages are formed between the position of the valve seat where the valve member collides and the entrance of the fuel injection hole whose cross section is elliptical, and the outlet of the concave passage is The fuel is provided so as to face open in the fuel injection hole, and the fuel that reaches the concave passage collides at the entrance of the fuel injection hole, and then goes downstream while diffusing in the elliptical fuel injection hole. Cylinder internal combustion characterized by being configured as follows Injection device.