JP5943060B2 - Fuel injection device - Google Patents

Description

  The present invention relates to a fuel injection device that injects fuel.

2. Description of the Related Art Conventionally, a fuel injection device that injects fuel into a cylinder of an internal combustion engine is known. The fuel injection device includes a valve body having a valve seat and an injection hole, and a needle valve provided inside the valve body so as to be reciprocally movable. When the needle valve is separated from the valve seat, fuel is injected from the nozzle hole, and when the needle valve is seated on the valve seat, fuel injection from the nozzle hole is shut off.
In the fuel injection device described in Patent Document 1, an inlet of an injection hole is provided on a virtual surface obtained by extending a valve seat formed in a tapered shape. As a result, the fuel that has passed through the valve seat flows directly into the nozzle hole inlet, and is injected from the nozzle hole outlet while maintaining the kinetic energy of the fuel.
The fuel injection device described in Patent Document 2 includes a plate-shaped injection hole plate at the end of the valve body. The nozzle hole plate has a tapered nozzle hole. Thereby, the fuel is guided to the inner peripheral wall of the nozzle hole, and the fuel is injected in a liquid film form from the nozzle hole outlet.

JP 2010-164060 A JP 2001-317431 A

However, since the fuel injection device of Patent Document 1 has a cylindrical injection hole, a liquid film of fuel injected from the injection hole becomes thick, and there is a possibility that atomization of the fuel spray is not sufficiently performed.
In the fuel injection device of Patent Document 2, the fuel that has passed through the valve seat flows into the nozzle hole after colliding with the inner wall of the nozzle hole plate. For this reason, the kinetic energy of the fuel is lost, and there is a possibility that atomization of the spray is not sufficiently performed.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a fuel injection device that enables high atomization of fuel spray.

According to the first aspect of the present invention, the fuel injection device is applied to a direct-injection gasoline engine that directly injects fuel into a combustion chamber of an internal combustion engine, and includes a valve body and a needle valve. A valve body formed in a bottomed cylindrical shape includes a fuel passage through which fuel flows, a tapered valve seat provided on an inner wall forming the fuel passage, a recess recessed in the axial direction on the downstream side of the valve seat, and a valve It has a plurality of nozzle holes that communicate from the inner wall to the outer wall of the recess located on a virtual surface that extends the seat toward the recess.
A needle valve provided inside the valve body so as to be reciprocally movable has a valve seat that can be seated on and separated from the valve seat, and a convex tip portion on the downstream side of the valve seat.
Further, the concave portion of the valve body has a flat portion perpendicular to the central axis of the valve body and a tapered surface portion formed on the outer periphery of the flat portion. The outer wall of the valve body, which is exposed to the combustion chamber of the internal combustion engine, on the side opposite to the needle valve is formed in a curved surface that is convex toward the combustion chamber. The inlets of the plurality of nozzle holes are provided in the tapered surface portion . The outlets of the plurality of nozzle holes are provided on the outer wall of the valve body that is formed in a convex curved shape on the combustion chamber side.
Since the inlet of the nozzle hole is located on a virtual plane obtained by extending the valve seat to the concave side, the main flow of fuel that has passed through the valve seat flows directly into the nozzle hole. This makes it possible to introduce the fuel into the nozzle hole while maintaining the kinetic energy of the fuel.

In the second aspect of the invention, the inner diameter on the injection hole inlet side is d1, and the inner diameter on the injection hole outlet side is d2. At this time, d1 and d2 have a relationship of d2> d1.
In the invention according to claim 3, the nozzle hole has a tapered shape in which the inner diameter gradually increases from the nozzle hole inlet side toward the nozzle hole outlet side.
As a result, the fuel flows along the inner peripheral wall of the nozzle hole while maintaining the kinetic energy. Therefore, a large gas phase is formed from the vicinity of the central axis of the nozzle hole to the vicinity of the inner peripheral wall of the nozzle hole located in the radially outward direction in the valve body. Therefore, the fuel injection device can increase the velocity gradient and reduce the thickness of the liquid film, so that the fuel spray can be highly atomized .

It is sectional drawing of the fuel-injection apparatus by one Embodiment of this invention. It is an enlarged view of the II part of FIG. It is an enlarged view of the III part of FIG. FIG. 4 is a view taken in the direction of arrow IV in FIG. 2, and is a diagram excluding a needle valve. It is sectional drawing of the VV line of FIG. It is a top view of the cylinder of the internal combustion engine in which the fuel injection device by one embodiment of the present invention is used. 1 is a cross-sectional view of an internal combustion engine in which a fuel injection device according to an embodiment of the present invention is used. (A) It is a schematic diagram which shows the flow velocity distribution of the fuel which flows through the nozzle hole of the fuel injection apparatus by one Embodiment of this invention. (B) It is a schematic diagram which shows the flow velocity distribution of the fuel which flows through the nozzle hole of the conventional fuel injection apparatus. It is a graph which shows the relationship between a speed gradient, the injection speed, or the particle size of a fuel, and A / Ds, and the relationship between a speed gradient and an injection speed. It is a graph which shows the relationship between a speed gradient, the injection speed, or the particle size of a fuel, and B / Ds. It is a graph which shows the relationship between the particle size or spray shrinkage rate of spray, and L / d1. It is a graph which shows the relationship between the particle size of a fuel, and the taper angle of a nozzle hole. It is a graph which shows the relationship between the fluctuation | variation of a flow velocity gradient, the particle size of spray, or an injection angle, and Ds / Dp. It is a graph which shows the relationship between a flow coefficient, an area reduction rate, a peeling angle, a velocity gradient, or an injection speed, and the angle θ3 formed by the valve seat and the tip. It is sectional drawing of the internal combustion engine in which the fuel-injection apparatus by 2nd Embodiment of this invention is used. It is sectional drawing of the internal combustion engine in which the fuel-injection apparatus by other embodiment of this invention is used.

Hereinafter, a plurality of embodiments according to the present invention will be described with reference to the drawings.
(First embodiment)
A fuel injection device according to an embodiment of the present invention is shown in FIGS. The fuel injection device 1 of this embodiment is applied to a direct injection gasoline engine. As shown in FIG. 7, the fuel injection device 1 is provided in a cylinder head 2 of an internal combustion engine. The cylinder head 2 is provided with an intake passage 3, an exhaust passage 4 and a spark plug 5. An intake valve 6 opens and closes the intake passage 3, and an exhaust valve 7 opens and closes the exhaust passage 4.

The configuration of the fuel injection device 1 will be described.
As shown in FIG. 1, the fuel injection device 1 includes a housing 10 formed in a cylindrical shape. The housing 10 integrally includes a first magnetic part 11, a nonmagnetic part 12, and a second magnetic part 13 in this order. The nonmagnetic part 12 prevents a magnetic short circuit between the first magnetic part 11 and the second magnetic part 13.
An inlet member 14 is provided at one end of the housing 10 in the axial direction. Fuel pressurized by a high-pressure pump (not shown) is supplied to a fuel inlet 15 provided in the inlet member 14. The fuel supplied to the fuel inlet 15 flows into the housing 10 via the fuel filter 16.

A coil 18 is wound around a spool 17 provided outside the diameter of the housing 10. A plate housing 19 is provided outside the diameter of the coil 18. A fixed core 20 and a movable core 21 are provided inside the coil 18 across the housing 10. The fixed core 20 is fixed to the housing 10, and the movable core 21 can reciprocate in the axial direction. The plate housing 19, the fixed core 20, and the movable core 21 are made of a magnetic material.
A coil spring 22 is provided across the inner side of the fixed core 20 and the inner side of the movable core 21. The coil spring 22 has a load adjusted by an adjusting pipe 23 press-fitted into the fixed core 20. The coil spring 22 biases the movable core 21 in a direction away from the fixed core 20.
When the coil 18 is energized from the terminal 25 of the connector 24, magnetic flux flows through the magnetic circuit formed by the fixed core 20, the first magnetic part 11, the plate housing 19, the second magnetic part 13, and the movable core 21, and the movable core 21 is magnetically attracted to the fixed core 20.

A cylindrical nozzle holder 26 is provided at the other end of the housing 10. A bottomed cylindrical valve body 30 is provided at the end of the nozzle holder 26 opposite to the housing 10.
The needle valve 40 is provided so as to be able to reciprocate over the inside of the housing 10, the inside of the nozzle holder 26, and the inside of the valve body 30. The needle valve 40 is fixed to the movable core 21 and moves together with the movable core 21. When the needle valve 40 is separated from the valve seat 31 formed in the valve body 30, the fuel is injected from the nozzle hole 32. When the needle valve 40 is seated on the valve seat 31, the fuel injection from the nozzle hole 32 is shut off.

As shown in FIG. 2, the valve body 30 has a tapered valve seat 31 having an inner diameter that decreases toward the tip on the inner wall forming the fuel passage 33.
The valve body 30 has a recess 34 that is recessed in the axial direction on the downstream side of the valve seat 31. The concave portion 34 has an inner wall formed in a taper shape having a straight longitudinal section, and an outer wall formed on a spherical surface having a curved longitudinal section.
The valve body 30 has a plurality of injection holes 32 communicating from the inner wall of the recess 34 to the outer wall. The plurality of injection holes 32 are provided on the inner wall of the recess 34 located on a virtual conical surface C in which the inlets of the valve seats 31 are extended to the recess. As a result, the main flow of fuel that has passed through the valve seat 31 is directly introduced into the nozzle hole 32. In addition, the main flow of fuel means a place where the flow rate (m ³ / s) is the largest in the flow of fuel.

The needle valve 40 has a valve seat 41 that can be seated on and separated from the valve seat 31 of the valve body 30. Further, the needle valve 40 has a convex tip portion 42 toward the space between the plurality of injection holes 32 on the downstream side of the valve seat 41. An angle θ1 (referred to as “valve seat central angle θ1”) formed by the bus and the bus in the longitudinal section of the valve seat 41 is 80 to 130 (°). An angle θ2 (referred to as “valve seat center angle θ2”) formed by the bus bar of the longitudinal section of the valve seat 31 and the bus bar is substantially the same as or slightly smaller than the valve seat center angle θ1.
Further, the angle θ3 formed by the valve seat 41 and the tip end portion 42 is 18 ≦ θ3 ≦ 27 (°).
A fuel chamber 35 is formed between the valve seat 41 of the needle valve 40 and the valve seat 31 and the recess 34 of the valve body 30. The fuel that has passed between the valve seat 31 and the valve seat 41 from the fuel passage 33 passes through the fuel chamber 35 and is introduced into the injection hole 32.

Here, the outer diameter of the valve seat 41 is Ds.
In the state where the needle valve 40 is fully lifted from the valve seat 31, the axial distance in the valve body 30 between the inlet of the injection hole 32 and the tip end portion 42 is denoted by A.
In the state where the needle valve 40 is fully lifted from the valve seat 31, the axial distance in the valve body 30 between the inner wall of the recess 34 on the center side of the nozzle hole 32 and the distal end portion 42 is defined as B.
At this time, Ds, A and B are
0.048 ≦ A / Ds ≦ 0.18,
B / Ds ≦ 0.18.

As shown in FIG. 3, the central axis of the virtual cone obtained by extending the inner peripheral wall of the injection hole 32 is referred to as the central axis P of the injection hole 32. The inner diameter of the virtual cone including the intersection of the extension line of the inner wall of the valve body 30 and the central axis P of the nozzle hole 32 is defined as the nozzle hole inlet side inner diameter d1. The inner diameter of the virtual cone including the intersection of the extension line of the outer wall of the valve body 30 and the central axis P of the injection hole 32 is defined as the injection hole outlet inner diameter d2. The distance between the intersection of the inner wall extension line of the valve body 30 and the central axis P of the injection hole 32 and the intersection of the extension line of the outer wall of the valve body 30 and the central axis P of the injection hole 32 is defined as the injection hole length L. .
The injection hole inlet side inner diameter d1 and the injection hole outlet side inner diameter d2 are d1 <d2. Thereby, the nozzle hole 32 is formed in a taper shape.
The nozzle hole length L and the nozzle hole inlet side inner diameter d1 are L / d1 ≧ 2.0.
Further, an angle θ (hereinafter referred to as “taper angle”) formed by a generatrix and a generatrix of the longitudinal section of the virtual cone extending the inner peripheral wall of the nozzle hole 32 is preferably 5 <θ <35 (°), Preferably, 15 <θ <35 (°), and more preferably 20 <θ <30 (°).
The angle θ4 formed by the inner wall of the nozzle hole located on the central axis side of the valve body and the central axis O of the valve body is:
−45 <θ4 <45 (°), and preferably −40 <θ4 <40 (°).

As shown in FIG. 4, the inlets of the plurality of nozzle holes 32 are provided at substantially equal intervals on a virtual circle D centering on the central axis O of the valve body 30. As a result, fuel of substantially the same flow rate is introduced into the plurality of nozzle holes 32 from the fuel passage 33 through the fuel chamber 35. Assuming that the diameter of the virtual circle D is Dp, 1.5 ≦ Ds / Dp ≦ 3. In FIG. 4, the outer edge of the needle valve 40 is indicated by a broken line 40.
The plurality of nozzle holes 32 are provided symmetrically with respect to the first virtual plane E with the central axis P including the central axis O of the valve body 30. As a result, as shown in FIG. 6, in the combustion chamber 8, the region α where the one intake passage 3 and the exhaust passage 4 are provided, and the region β where the other intake passage 3 and the exhaust passage 4 are provided, The fuel spray is injected substantially uniformly. In FIG. 6, one region α and the other region β are conceptually divided by an alternate long and short dash line E, and fuel spray is conceptually indicated by a broken line.

As shown in FIG. 4, at least one predetermined nozzle hole 321 among the plurality of nozzle holes 32 located on the ignition plug side is provided in a so-called inward opening. The injection hole 32 located on the ignition plug side refers to an injection hole located on the ignition plug side with respect to the virtual surface I that includes the central axis O of the valve body and is perpendicular to the virtual surface E.
As shown in FIG. 5, a virtual plane perpendicular to a virtual straight line F connecting the central axis O of the valve body 30 and the predetermined injection hole 321 and passing through the outer edge of the predetermined injection hole 321 is defined as a second virtual surface G. To do. When the predetermined injection hole 321 is inwardly opened, the virtual cone H obtained by extending the inner peripheral wall of the predetermined injection hole 321 to the combustion chamber 8 is positioned on the central axis O side of the valve body 30 with respect to the second virtual surface G. That means.
On the other hand, the plurality of nozzle holes 32 excluding the predetermined nozzle hole 321 are provided such that the central axis P of the inner peripheral wall of the nozzle hole 32 is directed from the inlet toward the outlet and away from the central axis O of the valve body 30.
Thereby, as shown in FIG. 7, the fuel injection device 1 injects fuel to the piston side in the combustion chamber. Therefore, the distance traveled by the fuel injected from the injection hole 32 is increased, and the fuel atomization is promoted.
Further, the plurality of injection holes 32 are provided in the combustion chamber when the piston 9 is at the bottom dead center, the virtual conical surface extending the inner peripheral wall of one injection hole 32 to the combustion chamber 8, and the inside of the other injection holes 32. A space γ is formed between the peripheral wall and a virtual conical surface extending to the combustion chamber 8. Thereby, fuel spray is uniformly injected into the combustion chamber, and the homogeneity of the air-fuel mixture is increased.
In FIG. 7, only the virtual conical surfaces of the two nozzle holes 32 are shown for ease of explanation. Further, an arrow T in FIG. 7 indicates a tumble flow.

Next, the effect of the fuel injection device 1 of the present embodiment will be described.
(1) The flow velocity distribution of the fuel flowing through the nozzle holes 32 of the fuel injection device 1 of this embodiment is shown in FIG. In FIG. 8 (A), the part which attached | subjected the code | symbol X and Y is the liquid phase X and the liquid phase Y, and the part of the code | symbol Z is the gaseous phase Z. In FIG. The liquid phase X has the highest flow rate, and then the liquid phase Y has the highest flow rate.
In the present embodiment, by forming the injection hole 32 in a tapered shape having an inner diameter of the outlet larger than the inner diameter of the inlet, the fuel flows along the inner peripheral wall of the injection hole 32 as shown in FIG. For this reason, the fuel flowing through the nozzle hole 32 has a large flow rate in the vicinity of the inner peripheral wall of the nozzle hole 32 located on the central axis O side (in the radial direction) of the valve body 30. The liquid phases X and Y spread thinly along the inner peripheral wall of the nozzle hole 32. A large gas phase Z is formed from the vicinity of the central axis P of the nozzle hole 32 to the vicinity of the inner peripheral wall of the nozzle hole 32 positioned in the radially outward direction in the valve body 30.
As a result, the fuel is injected from the nozzle hole 32 as a thin liquid film. In the present embodiment, the fuel injected from the injection hole 32 maintains the kinetic energy of the fuel and has a large velocity gradient, so that the splitting of the liquid film is promoted. Therefore, the fuel spray can be highly atomized.
On the other hand, the flow velocity distribution of the fuel flowing through the cylindrical injection hole 32 of the conventional fuel injection device 1 is shown in FIG. In FIG. 8B, the portions with reference signs U and V are the liquid phase U and the liquid phase V, and the reference sign W is the gas phase W. The liquid phase U has the highest flow rate, and then the liquid phase V has the highest flow rate.
As shown in FIG. 8B, in the cylindrical injection hole 32 of the conventional fuel injection device, the liquid phases U and V are injected from the inner peripheral wall of the injection hole 32 located in the radially inward direction in the valve body 30. It flows in the vicinity of 32 central axes P. A small vapor phase W is formed in the vicinity of the inner peripheral wall of the injection hole 32 located in the radially outward direction in the valve body 30. Thereby, there is a concern that the liquid film of the fuel injected from the injection hole 32 becomes thick, and the splitting of the liquid film is reduced.

(2) FIG. 9A shows the relationship between the velocity gradient and A / Ds and the relationship between the injection velocity and A / Ds. FIG. 9B shows the relationship between the fuel particle size and A / Ds. FIG. 9C shows the relationship between the velocity gradient and the injection velocity.
When the injection hole 32 is provided so that the central axis P of the inner peripheral wall of the injection hole 32 is away from the central axis O of the valve body 30 from the inlet toward the outlet, the distance between the inlet of the injection hole 32 and the tip end portion 42 is provided. When A is increased, the angle formed between the main flow of the fuel that has passed through the valve seat 31 and the central axis P of the injection hole 32 increases. Thereby, the force by which the main flow of fuel is pressed against the inner peripheral wall of the nozzle hole 32 is weakened. Therefore, as shown in FIG. 9A, the velocity gradient is small when 0.18 <A / Ds.
When the velocity gradient becomes small, the division of the fuel injected from the injection hole 32 is not promoted. For this reason, as shown in FIG. 9B, when 0.18 <A / Ds, the particle size of the fuel spray increases.
The particle size of the fuel spray is based on SMD (Sauter mean diameter).

Here, as shown in FIG. 9C, when the speed gradient is increased, the injection speed at which the fuel spray is injected from the nozzle hole outlet decreases.
For this reason, as shown in FIG. 9A, when A / Ds <0.048, the injection speed becomes small. When the injection speed is reduced, the division of the fuel injected from the injection hole 32 is not promoted. For this reason, as shown in FIG. 9B, when A / Ds <0.048, the particle size of the fuel spray becomes large.
Therefore, in this embodiment, the relationship between the distance A between the inlet of the injection hole 32 and the tip end portion 42 and the outer diameter Ds of the valve seat 41 is 0.048 ≦ A / Ds ≦ 0.18.

(3) FIG. 10A shows the relationship between the velocity gradient and B / Ds and the relationship between the injection velocity and B / Ds. FIG. 10B shows the relationship between the fuel particle size and B / Ds.
When the distance B between the inner wall of the recess 34 on the center side of the nozzle hole 32 and the tip end portion 42 is increased, the fuel that has passed through the valve seat 31 passes near the center of the fuel chamber 35 and is positioned on the opposite side in the radial direction. The amount flowing into the nozzle hole 32 that increases is increased. Thereby, the force by which the main flow of fuel is pressed against the inner peripheral wall of the nozzle hole 32 is weakened.
Therefore, as shown in FIG. 10A, the velocity gradient is small when 0.18 <B / Ds. For this reason, as shown in FIG. 10B, when 0.18 <B / Ds, the particle size of the fuel spray becomes large. When the distance B is changed, the injection speed is substantially constant.
Therefore, in the present embodiment, the relationship between the distance B between the inner wall of the recess 34 on the center side of the nozzle hole 32 and the distal end portion 42 and the outer diameter Ds of the valve seat 41 is B / Ds ≦ 0.18. Yes.

(4) FIG. 11A shows the relationship between the spray particle size and L / d1, and FIG. 11B shows the relationship between the spray shrinkage rate and L / d1. The spray contraction rate is the spray angle (injection angle) of fuel actually injected / inclination of the injection hole (target injection angle).
The fuel flowing through the nozzle hole 32 has a large flow rate on the inner peripheral wall of the nozzle hole 32 located on the central axis O side of the valve body 30. For this reason, the injection direction of the fuel spray injected from the injection hole 32 is controlled by the inner peripheral wall of the injection hole 32 in the radially inward direction of the valve body 30. If the inner peripheral wall of the injection hole 32 in the radially inward direction of the valve body 30 is long, the spray contraction rate approximates to 1.0. On the other hand, if the inner peripheral wall of the injection hole 32 in the radially inward direction of the valve body 30 is short, the spray contraction rate becomes small. Therefore, as shown in FIG. 11B, when L <2.0, the spray shrinkage rate becomes small. When the spray contraction rate decreases, it becomes difficult to inject fuel spray uniformly into the cylinder.
Therefore, in this embodiment, the relationship between the nozzle hole length L and the nozzle hole inlet side inner diameter d1 is set to L / d1 ≧ 2.0. Thereby, the injection direction of the fuel spray injected from the injection hole 32 can be controlled.

(5) The relationship between the fuel particle size and the taper angle θ of the nozzle hole 32 is shown in FIG. The taper angle θ refers to an angle θ formed between a generatrix and a generatrix of a vertical section of a virtual cone that extends the inner peripheral wall of the nozzle hole 32.
As shown in FIG. 12, when the taper angle θ of the nozzle hole 32 is 5 <θ <35 (°), the particle size of the spray is small, and when 15 <θ <35 (°), the particle size of the spray is even smaller. When 20 <θ <30 (°), the particle size of the spray is even smaller.
In the present embodiment, in the range of the taper angle θ of the nozzle hole 32 of 5 to 35 (°), the particle size of the fuel spray is set within the allowable range according to the sensitivity of the engine to which the fuel injection device 1 is applied. Is done.

(6) The relationship between the flow velocity gradient and Ds / Dp is shown in FIG. 13 (A), the relationship between the spray particle size and Ds / Dp is shown in FIG. 13 (B), and the injection angle variation and Ds / Dp The relationship is shown in FIG.
As shown in FIG. 13A, when the value of Ds / Dp is decreased, the velocity gradient is decreased. Accordingly, as shown in FIG. 13B, when the value of Ds / Dp is decreased, the particle size is increased. As shown in FIG. 13C, when Ds / Dp <1.5 and Ds / Dp> 3.0, the variation in the injection angle of the fuel spray with respect to the angle of the injection hole 32 becomes large. .
Therefore, in this embodiment, the relationship between the diameter Dp of the virtual circle D provided with the nozzle hole inlet and the outer diameter Ds of the valve seat 41 is 1.5 ≦ Ds / Dp ≦ 3.

(7) The relationship between the angle θ3 formed by the valve seat 41 and the tip 42 and the flow coefficient is shown in FIG. 14A, and the relationship between the angle θ3 and the area reduction rate is shown in FIG. FIG. 14C shows the relationship between θ3 and the peel angle, FIG. 14D shows the relationship between the angle θ3 and the velocity gradient, and FIG. 14E shows the relationship between the angle θ3 and the injection velocity.
As shown in FIG. 14 (A), the flow coefficient becomes 0.6 or more when the angle θ3 is in the range of 18 to 27 (°). As shown in FIG. 14B, as the angle θ3 increases, the reduction rate of the cross-sectional area of the fuel chamber 35 decreases. On the other hand, as shown in FIG. 14C, the degree of fuel peeling from the tip end portion 42 increases as the angle θ3 increases.
Also, as shown in FIG. 14D, the velocity gradient decreases as the angle θ3 increases. As shown in FIG. 14E, the injection speed increases as the angle θ3 increases.
In the present embodiment, the angle θ3 formed by the valve seat 41 and the tip portion 42 is 18 ≦ θ3 ≦ 27 (°), so that the main flow of fuel passes through the seat portion and then reaches the nozzle hole inlet The loss of kinetic energy of the fuel can be suppressed.

(Second Embodiment)
FIG. 15 shows an internal combustion engine in which the fuel injection device 1 according to the second embodiment of the present invention is used. In the following embodiments, substantially the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
Also in this embodiment, the predetermined nozzle hole 321 located in the spark plug side among the plurality of nozzle holes 32 is provided in a so-called inner opening. For this reason, the fuel injection device 1 injects fuel to the piston side in the combustion chamber.
Further, the plurality of injection holes 32 are provided in the combustion chamber when the piston 9 is at the bottom dead center, the virtual conical surface extending the inner peripheral wall of one injection hole 32 to the combustion chamber 8, and the inside of the other injection holes 32. A space γ is formed between the peripheral wall and a virtual conical surface extending to the combustion chamber 8. Thereby, fuel spray is uniformly injected into the combustion chamber, and the homogeneity of the air-fuel mixture is increased.
In FIG. 15, only the virtual conical surfaces of the two nozzle holes 32 are shown for ease of explanation.

(Other embodiments)
In the above-described embodiment, the fuel injection device is attached to the side surface of the cylinder of the internal combustion engine. On the other hand, in the present invention, as shown in FIG. 16, a fuel injection device may be attached near the center of the cylinder.
Further, the fuel injection device may be attached to the intake passage or the exhaust passage.
In the above-described embodiment, the fuel injection device applied to the gasoline engine has been described. On the other hand, the present invention may be applied to a diesel engine.
In the embodiment described above, six nozzle holes are provided in the valve body. On the other hand, the present invention is not limited to the number of nozzle holes.
In the embodiment described above, the tip of the valve body is formed in a spherical shape. In contrast, in the present invention, the tip of the valve body may be flat.
As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 1 ... Fuel injection apparatus 30 ... Valve body 31 ... Valve seat 32 ... Injection hole 33 ... Fuel passage 34 ... Recess 40 ... Needle valve 41 ... Valve seat 42- ..Tip

Claims (3)

A fuel injection device applied to a direct-injection gasoline engine that directly injects fuel into a combustion chamber of an internal combustion engine,
A fuel passage through which fuel flows, a tapered valve seat provided on an inner wall forming the fuel passage, a recess recessed in the axial direction on the downstream side of the valve seat, and the valve seat A valve body having a plurality of nozzle holes leading from the inner wall to the outer wall of the recess located on a virtual surface extending to the recess side;
A valve seat provided inside the valve body so as to be capable of reciprocating, and seatable and separable from the valve seat, and a needle valve having a convex tip on the downstream side of the valve seat,
The concave portion of the valve body has a flat portion perpendicular to the central axis of the valve body, and a tapered surface portion formed on the outer periphery of the flat portion,
The outer wall of the valve body that is exposed to the combustion chamber of the internal combustion engine on the side opposite to the needle valve is formed in a curved surface that is convex toward the combustion chamber side,
The inlets of the plurality of nozzle holes are provided in the tapered surface portion,
The outlets of the plurality of injection holes are provided on the outer wall of the valve body formed in a curved surface convex toward the combustion chamber . If the inner diameter on the injection hole inlet side is d1, and the inner diameter on the injection hole outlet side is d2,
2. The fuel injection device according to claim 1, wherein a relationship of d2> d1 is satisfied.   3. The fuel injection device according to claim 2, wherein the nozzle hole has a tapered shape whose inner diameter gradually increases from the nozzle hole inlet side toward the nozzle hole outlet side.

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