JP2015172357A - fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems with a conventional fuel injection valve that the structure of a spray shape variable mechanism is complicated for varying the spray shape of a fuel at a fuel injection nozzle.SOLUTION: Opening shapes of a plurality of injection hole inlets 11 and 21 of slit injection holes 8 and 9 formed in a tip end portion of a nozzle body 2 of a fuel injection nozzle each take on a flat slit (elliptical) shape satisfying a relation of b<a≤Ls/N. By so configuring, it is possible to vary the spray shape of a fuel injected into a combustion chamber from the slit injection holes 8 and 9 between a time of a range in a state 1 in which a needle lift amount is small and a time of a range in a state 2 in which the needle lift amount is large. It is thereby possible to realize a spray shape variable mechanism capable of varying the spray shape of the fuel injected from the slit injection holes 8 and 9 between the range in the state 1 and the range in the state 2, with a relatively simple structure.

Description

  The present invention relates to a fuel injection valve in which an opening shape of an injection hole inlet of a fuel injection nozzle that injects fuel into a cylinder of an internal combustion engine is a flat slit shape.

[Conventional technology]
In recent years, for example, in response to the operating state of an internal combustion engine (engine) mounted on a vehicle such as an automobile, the fuel spray angle, the fuel reach distance, etc., injected into the combustion chamber formed in the cylinder of the engine Attempts have been made to change the spray shape (spray characteristics). Exhaust emissions can be reduced by changing the shape of the fuel spray injected into the combustion chamber of the engine cylinder in accordance with the operating state of the engine.
As such a fuel injection valve, a fuel injection valve provided with a fuel injection nozzle for injecting fuel into a combustion chamber of a cylinder of an engine is known (see, for example, Patent Documents 1 and 2).

The fuel injection nozzle has a conical-shaped valve portion on one end side, and includes a needle that can reciprocate in the axial direction, and a cylindrical nozzle body that supports the needle so as to reciprocate in the axial direction. Yes.
The nozzle body includes a conical seat surface including an annular seat portion on which the needle valve portion can be seated, and an annular shape formed between the needle valve portion and the seat surface when the needle is opened. A bottomed cylindrical sac portion that forms a sac chamber that communicates with the fuel flow path, and a plurality of nozzle holes that communicate with the sac chamber.
Further, six triangular guide surfaces (concave surfaces) are formed on the conical surface of the valve portion of the needle by chamfering. These guide surfaces form a spray shape changing unit for setting the fuel spray angle in the first state to be relatively large and setting the fuel spray angle in the second state to be relatively small.

Here, the fuel injection valve of Patent Document 1 (hereinafter, Conventional Example 1) is provided with a needle lift amount variable mechanism for changing the needle lift amount. This needle lift amount variable mechanism can be set to a first state in which the needle lift amount is relatively small and a second state in which the needle lift amount is relatively large by moving the needle along the axial direction thereof. It is.
In the first operating region where the engine load is relatively low, the needle lift amount is set to the first state that is relatively small, and the fuel is highly diffused and penetrated from the plurality of nozzle holes toward the combustion chamber of the cylinder. Injected at.
Further, in the second operation region where the engine load is relatively high, the needle lift amount is set to the second state where the amount of the needle lift is relatively large, and the fuel is diffused from the plurality of nozzle holes into the combustion chamber of the cylinder and has a low diffusion and high penetration force. Injected at.

The fuel injection nozzle of Patent Document 2 (hereinafter, Conventional Example 2) has one flat hole-shaped slit injection hole that can enhance the atomization effect of fuel spray injected into the combustion chamber formed in the cylinder. Only formed.
The slit injection hole is a flat slit-shaped fuel injection hole that penetrates the inside and outside of the sac portion on the tip side of the nozzle body. The slit nozzle hole is provided with a plurality of recesses that generate a disturbance in the flow of fuel passing through the slit nozzle hole by extending the cross-sectional area of the nozzle hole channel in the slit nozzle hole in the middle. ing. These recesses cause disturbance in the flow of the fuel passing through the slit hole, thereby increasing the splitting force of the fuel injected from the nozzle hole outlet of the slit nozzle hole and atomizing the fuel spray.

[Conventional technical problems]
However, in the fuel injection valve of the conventional example 1, the fuel spray shape injected from the plurality of injection holes can be changed to improve the fuel consumption and reduce the exhaust emission. A needle lift amount variable mechanism that can change the needle lift amount in two stages in addition to the needle shape processing including chamfering forming a variable mechanism is provided, and the fuel spray shape in the fuel injection nozzle is changed. There is a problem that the structure of the spray shape variable mechanism is complicated.

  On the other hand, in the fuel injection valve of Conventional Example 2, since it is necessary to form a plurality of recesses in the nozzle hole wall surface of the slit nozzle hole, there is a problem that the processing cost of the nozzle body of the fuel injection nozzle becomes high. Further, since only one slit nozzle hole for injecting fuel is provided in the combustion chamber of the cylinder of the internal combustion engine, a fuel lump floating in the space can be formed without contacting the combustion chamber wall surface of the cylinder. Can not. In addition, because the high penetration force remains, the fuel burns, the high-temperature combustion gas collides violently with the combustion chamber wall surface and the cylinder head wall surface, and the heat energy escapes from that part, so that heat loss is large. There's a problem.

JP-A-2005-133585 JP 2010-084755 A

  It is an object of the present invention to provide a spray shape variable mechanism (for example, a fuel injection nozzle in a fuel injection nozzle) that can change the spray shape of fuel injected from a plurality of nozzle holes between a first state and a second state. It is an object of the present invention to provide a fuel injection valve capable of realizing a spray shape changing mechanism for changing the spray shape with a relatively simple structure without requiring a complicated processing step.

According to the first aspect of the present invention (fuel injection valve), the plurality of nozzle holes of the fuel injection nozzle that injects fuel into the cylinders of the internal combustion engine has at least the opening shape of the plurality of nozzle holes b <a By exhibiting a flat slit shape satisfying the relationship of ≦ Ls / N, the second state in which the needle lift amount is relatively small and the second state in which the needle lift amount is relatively large is obtained although the structure is simple. It becomes possible to change the spray shape of the fuel injected from the plurality of nozzle holes depending on the state.
Specifically, the spray shape in the first state is a low penetration / high diffusion spray, and the spray shape in the second state is a high penetration / low diffusion spray.
Thereby, the spray shape variable mechanism (for example, the fuel spray shape in the fuel injection nozzle) that can change the spray shape of the fuel injected from the plurality of nozzle holes between the first state and the second state. It is possible to realize a spray shape changing mechanism for changing with a relatively simple structure without requiring a complicated processing step.

(A) is sectional drawing which showed the fuel-injection nozzle in the area | region of the state 1, (b) is I (b) -I (b) sectional drawing of (a) (Example 1). (A) is sectional drawing which showed the fuel-injection nozzle in the area | region of the state 2, (b) is II (b) -II (b) sectional drawing of (a) (Example 1). It is sectional drawing which showed the fuel-injection nozzle at the time of a needle fully closed (Example 1). (A) is IV (a) -IV (a) sectional drawing of Fig.1 (a)-FIG.3 (a), (b) is IV (b)-of FIG.1 (a)-FIG.3 (a). FIG. 4C is a cross-sectional view of IV (b), and FIG. 4C is an explanatory view showing the opening shape of the first and second injection hole inlets (Example 1). It is the graph which showed the change of the spray length in the high injection quantity in which the area | region of the state 1 and the area | region of the state 2 exist (Example 1). It is the graph which showed the change of the spray length in the low injection quantity in which only the area | region of the state 1 exists (Example 1). (A) is explanatory drawing which showed estimation of the fuel flow in a fuel-injection nozzle in the state 1 area | region, (b) is explanatory drawing which showed estimation of the fuel flow in a fuel-injection nozzle in the area | region of the state 2 (Example 1). (A)-(g) is explanatory drawing which showed the opening shape of the 1st, 2nd nozzle hole entrance (Example 1). It is the graph which showed the comparison result of the spray length of fuel (Example 1). It is the graph which showed the comparison result of the spray volume of fuel (Example 1). (A) is sectional drawing which showed the some 1st nozzle hole flow path, (b) is sectional drawing which showed the some 2nd nozzle hole flow path (Example 2).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of Example 1]
1 to 10 show an injector (Embodiment 1) to which a fuel injection valve of the present invention is applied.

An injector (fuel injection valve of an internal combustion engine) of this embodiment injects fuel spray in a mist form into a combustion chamber formed in a cylinder of an internal combustion engine (hereinafter referred to as an engine) such as a diesel engine for driving a vehicle such as an automobile. This is a direct injection type fuel injection valve.
The injector has a fuel injection nozzle (fuel injection nozzle for an internal combustion engine: needle 1, nozzle body 2) that injects fuel into the combustion chamber of the cylinder of the engine, and a lift amount of the needle 1 that is a valve body of the fuel injection nozzle. And a variable needle lift amount variable mechanism.

The fuel injection nozzle has a conical valve portion 3 on one end side (tip side) in the axial direction, extends straight in the axial direction, and can reciprocate in the axial direction, and the needle 1 A cylindrical nozzle body 2 is inserted and supported so as to be reciprocally movable in the axial direction, and a spray shape variable mechanism capable of changing the spray shape of fuel injected from the tip end side of the nozzle body 2 in the axial direction. .
The fuel injection nozzle is provided on the upstream side of the plurality of slit injection holes 8, 9 for injecting fuel and the flow direction of the fuel from these slit injection holes 8, 9, and communicates with the plurality of slit injection holes 8, 9. The sac chamber 7 has a fuel passage 6 that is provided upstream of the sac chamber 7 in the fuel flow direction and communicates with the sac chamber 7, and a plurality of slit nozzle holes 8 are formed by opening and closing the fuel passage 6. , 9 is provided with a nozzle body 2 containing a needle 1 for opening and closing.

The fuel injection nozzle is configured so that the valve portion 3 of the needle 1 is seated and separated from the nozzle seat 5 having a conical surface formed on the inner surface of the nozzle hole peripheral portion 4 of the nozzle body 2, so that the fuel flow on the upstream side Fuel injection from a plurality of slit injection holes 8 and 9 respectively opened at the wall surface (sack wall surface) of the concave sac chamber 7 into which fuel is introduced from the passage 6 is controlled.
Here, the fuel flow path 6 is an annular flow path formed between the valve portion 3 of the needle 1 and the nozzle seat 5 when the needle is opened.
The sac chamber 7 is formed in a bottomed cylindrical sack portion (circular top portion) 10 provided at the tip of the nozzle hole peripheral portion 4 of the nozzle body 2. At least one or more (plural) slit nozzle holes 8 and at least one or more (plural) slit nozzle holes 9 are formed in the sack portion 10 so as to penetrate therethrough.

The needle lift amount variable mechanism has a needle lift in a first state where the lift amount of the needle 1 is relatively small (hereinafter, state 1) and a second state where the lift amount of the needle 1 is relatively large (hereinafter, state 2). The amount is to be set.
In the fuel injection nozzle of the present embodiment, the flow passage cross-sectional area of the fuel flow passage 6 in the state 1 is smaller than the flow passage cross-sectional area of the fuel flow passage 6 in the state 2, and the throttle amount for reducing the flow rate of the fuel Becomes larger.
The needle lift amount variable mechanism is installed outside the nozzle body 2 (injector body) of the fuel injection nozzle.

The spray shape variable mechanism is provided in the nozzle hole peripheral portion 4 of the nozzle body 2 of the fuel injection nozzle. This spray shape variable mechanism is used in the region of the state 1 in which the needle lift amount is relatively small, that is, in the region of the state 2 in which the needle lift amount is relatively large. The spray shape of the fuel injected from the slit injection holes 8 and 9 is changed depending on the time, that is, when the flow passage cross-sectional area of the fuel flow passage 6 is relatively large.
The details of the spray shape variable mechanism will be described later.

The needle lift amount variable mechanism includes two sets of first and second electromagnetic actuators (solenoids).
The first and second solenoids are accommodated together with the proximal end side of the needle 1 inside a cylindrical injector body (housing) connected to the proximal end side of the nozzle body 2. These first and second solenoids are provided with an external connection connector, and are configured to be electronically controlled by an injector drive current applied from an engine control unit (electronic control unit: ECU). As a result, the fuel injection amount and the fuel injection timing injected from the plurality of slit injection holes 8 and 9 are variably controlled.

The first solenoid includes a first solenoid coil (hereinafter referred to as a first coil) wound around the outer periphery of an insulating synthetic resin first bobbin, and a coil inner periphery disposed on the inner peripheral side of the first coil. Side fixed core (for example, cylindrical first stator core), coil outer peripheral side fixed core (for example, cylindrical first yoke) disposed on the outer peripheral side of the first coil, and reciprocating movement within the first stator core And a movable core (first armature). The first solenoid is attached with a first return spring (hereinafter referred to as a first spring) that urges the first armature in the valve closing (seat) direction of the needle 1.
In addition, the coil outer peripheral side fixed core is provided if necessary.

The first armature is fixed to the proximal end (the other end, proximal to the axial direction of the needle 1) opposite to the axial distal end (one end) of the needle 1 so as to be integrally movable. ing.
When the first coil is supplied with power (applied with current or energized), the first armature is separated from the magnetic attraction portion (for example, the first armature by a predetermined distance (first axial distance)) of the first stator core. It is a magnetic flux generation means (magnetic force generation means) that generates a magnetic force attracted to the first opposing portion.
Further, the first armature is opposed to the magnetic attraction portion of the first stator core with a first axial distance (first gap) when energization to the first coil is stopped (OFF). Be placed.
A connecting member (for example, a shaft) is provided between the base end side of the needle 1 in the axial direction and the first armature between the base end side of the needle 1 and the first armature. May be.

In the first solenoid, when the first coil is energized (ON), the needle 1, the first armature, and the like stroke from the initial position (default position) to the proximal end side in the solenoid axial direction. When energization of the first coil is stopped (OFF), the needle 1 and the first armature and the like are returned to the default position by the biasing force (elastic restoring force) of the first spring.
As a result, when only the first coil is ON, the region where the fuel injection rate depends on the needle lift amount is low, that is, the needle lift amount is set to state 1 which is smaller than state 2. The At this time, the cross-sectional area of the fuel flow path 6 is smaller than that in the state 2.

The second solenoid includes a second solenoid coil (hereinafter referred to as a second coil) wound around the outer periphery of a second bobbin made of an insulating synthetic resin, and a coil inner periphery disposed on the inner peripheral side of the second coil. Side fixed core (for example, cylindrical second stator core), coil outer peripheral side fixed core (for example, cylindrical second yoke) disposed on the outer peripheral side of the second coil, and reciprocating movement within the second stator core Movable core (second armature). Further, a second return spring (hereinafter referred to as a second spring) that urges the second armature in the valve closing (seat) direction of the needle 2 is attached to the second solenoid.
In addition, the coil outer peripheral side fixed core is provided if necessary.

When the second coil is supplied with electric power (when current is applied or energized), the second armature is separated from the magnetic attraction portion (for example, the second armature by a predetermined distance (second axial distance)) of the second stator core. It is a magnetic flux generation means (magnetic force generation means) that generates a magnetic force attracted to the opposing second opposing portion.
The second armature can be integrally moved to the proximal end portion (the other end portion, the proximal end side of the first armature coupling portion of the needle 1) opposite to the distal end portion (one end portion) of the needle 1 in the axial direction. It is fixed.

Further, the second armature has a second axial distance (about twice the first gap) between the magnetic attraction portion of the second stator core when energization to the first and second coils is stopped (OFF). A large second gap) is arranged opposite to each other. The second armature has a second axial distance (first gap) between the second armature and the magnetic attraction portion of the second stator core when the first coil is turned on and energization to the second coil is stopped (OFF). Of the second gap of the same degree).
A connecting member (for example, a shaft) that connects the base end side and the second armature from the first armature connecting portion of the needle 1 between the base end side and the second armature from the first armature connecting portion of the needle 1. ) May be provided.

In the second solenoid, when the second coil is energized (ON), the needle 1, the second armature, and the like stroke from the initial position (default position) to the proximal end side in the solenoid axial direction. When energization to the second coil is stopped (OFF), the needle 1 and the second armature and the like are returned to the default position by the urging force (elastic restoring force) of the second spring.
Thereby, when both the first coil and the second coil are turned on, the needle lift amount in which the fuel flow rate depends on the total cross-sectional area of the nozzle hole, that is, the needle lift amount is larger than that in the state 1. Set to state 2. At this time, the cross-sectional area of the fuel flow path 6 is larger than that in the state 1.
The connector for external connection is used for electrical connection between the first coil and the second coil and an external circuit (external power supply or external control circuit: ECU).

The fuel injection nozzle of the present embodiment has a flat slit (the opening shape of the plurality of slit injection holes 8, particularly the plurality of injection hole inlets 11, the plurality of injection hole outlets 12, and the plurality of injection hole flow passages 13). In addition, the opening shape of the plurality of slit nozzle holes 9, particularly the opening shape of the plurality of nozzle hole inlets 21, the plurality of nozzle hole outlets 22, and the plurality of nozzle hole channels 23, is a flat slit (long). (Circle) shape.
The fuel injection nozzle injects fuel into a combustion chamber formed in the cylinder of the engine. The needle 1 is capable of reciprocating in the nozzle axis direction, and the tip end side of the needle 12 is capable of reciprocating in the nozzle axis direction. It is composed of a bottomed cylindrical nozzle body 2 to be accommodated.
The nozzle body 2 is a bottomed cylindrical valve body (needle support member) that supports the needle 1 so as to be reciprocally movable in the axial direction thereof.

The nozzle body 2 includes a bottomed cylindrical nozzle hole peripheral portion 4 that is exposed to the combustion chamber of the cylinder of the engine and directly exposed to the combustion chamber of the engine. This nozzle hole peripheral portion 4 includes an annular seat portion (valve seat) 17 on which the valve portion 3 of the needle 1 is seated, and is circular between the valve portion 3 of the needle 1 when the needle 1 is opened (lifted). A nozzle sheet 5 that forms an annular fuel flow path 6, a sac chamber 7 that communicates with the fuel flow path 6, and a plurality of slits that communicate with the sac chamber 7 and inject fuel when the needle 1 is opened (lifted). The nozzle holes 8 and 9 are provided.
Here, the plurality of slit nozzle holes 8 pass through the base end side of the bottomed cylindrical sack portion 10 in which the sac chamber 7 is formed, and communicate with the inside and outside of the base end side of the sack portion 10. It is an internal / external communication hole (a group of at least two slit nozzle holes). Further, the plurality of slit injection holes 9 pass through the front end side of the sac portion 10 from the positions where the plurality of slit injection holes 8 are formed, and communicate with the inside and outside of the front end side of the sack portion 10 (at least 2). Group of slit nozzle holes).

A nozzle sheet 5 including a sheet portion 17 is provided on the inner peripheral surface of the reduced diameter portion 18 of the nozzle body 2. The nozzle sheet 5 is provided on the upstream side in the fuel flow direction from the injection hole inlets 11 and 21 of the plurality of slit injection holes 8 and 9.
The nozzle sheet 5 corresponds to a “sheet surface” in the claims.
The sac chamber 7 is a fuel collecting portion that collects fuel distributed in an annular shape in the fuel flow path 6 and communicates with the plurality of slit injection holes 8 and 9 when the needle 1 is opened (lifted).
Further, a conical sack portion 10 that forms a sac chamber 7 is integrally formed at the tip of the nozzle hole peripheral portion 4 of the nozzle body 2.
Details of the nozzle body 2 will be described later.

The needle 1 of the present embodiment is installed so as to be reciprocally movable in the guide hole of the nozzle body 2 and is installed on the center line of the nozzle body 2. The needle 1 has an axial portion that is accommodated in a guide hole of the nozzle body 2. On the distal end side of the axial direction portion, a substantially two-stage conical surface shaped valve portion 3 is provided. Further, the proximal end side of the needle 1 in the axial direction is accommodated in the injector body so as to be reciprocally movable.
Further, a cylindrical sliding portion extending in the axial direction and a cylindrical small-diameter shaft portion 30 having an outer diameter smaller than that of the sliding portion are provided on the base end side of the axial direction portion. The outer peripheral surface of the sliding portion is a sliding surface that can slide with respect to a hole wall surface of a sliding hole (guide hole) provided on the proximal end side of the nozzle body 2.
Each part of the needle 1 is provided by forging, machining (cutting, grinding) or the like.

The valve portion 3 of the needle 1 is provided at the distal end portion (end portion on the injection hole side) of the needle 1 in the fuel flow direction, and is seated on and separated from the nozzle seat 5 of the nozzle body 2. The slit nozzle holes 8 and 9 are closed and opened.
The valve portion 3 includes a first reduced diameter portion 31 in which the outer diameter gradually decreases from the edge line of the small diameter shaft portion 30 toward the tip, and an outer portion from the edge line of the first reduced diameter portion 31 toward the tip. The second reduced diameter portion 32 whose diameter is gradually reduced is integrally formed.

On the outer peripheral surface of the first reduced diameter portion 31, a truncated cone-shaped first conical surface whose outer diameter gradually decreases from the proximal end side of the first reduced diameter portion 31 toward the distal end side of the first reduced diameter portion 31. Is formed.
On the outer peripheral surface of the second reduced diameter portion 32, the outer diameter gradually decreases from the proximal end side of the second reduced diameter portion 32 toward the distal end (pointed end) of the second reduced diameter portion 32, and the first conical surface The second conical surface has a conical shape with a steeper (taper) angle.
An annular intersection ridgeline (sheet line) formed between two adjacent first and second conical surfaces is in close contact with the sheet portion 17 of the nozzle sheet 5 of the nozzle body 2 in a liquid-tight manner. It has the function as the annular seal part 33 to do. Note that the number of the reduced diameter portions may be two or three or any number. Further, an annular intersection ridge line (sheet line) formed between two adjacent upper conical surfaces in the drawing and lower conical surfaces in the drawing serves as a seal portion.

Next, details of the nozzle body 2 of the present embodiment will be described with reference to FIGS.
The nozzle body 2 of the present embodiment is made of metal and has a hardness (rigidity) that does not deform with respect to the pressure of the high-pressure fuel.
A nozzle seat 5 including a seat portion 17 on which the valve portion 3 of the needle 1 can be seated is provided on one end side (tip side) of the nozzle body 2 in the axial direction. The nozzle sheet 5 defines the fully closed position of the needle 1 when the needle 1 is seated. The nozzle sheet 5 is a conical surface whose inner diameter gradually decreases toward one end.

A bottomed cylindrical sack portion 10 is provided downstream of the nozzle sheet 5 in the fuel flow direction. A sack chamber 7 serving as a sack volume is formed inside the sack portion 10. The sac chamber 7 communicates the fuel flow path 6 and the plurality of slit nozzle holes 8, 9, and collects fuel that flows in an annular manner in the fuel flow path 6 to distribute and supply the fuel to the plurality of slit nozzle holes 8, 9. It is a fuel assembly part.
On the nozzle shaft (CL) extending straight in the center line direction of the nozzle body 2, there is a coupling surface (contact surface) that is liquid-tightly contacted with the contact surface of the injector body that houses the first and second solenoids. Nozzle holes (axial holes) extending straight to the sac chamber 8 and the slit nozzle holes 8 and 9 are provided. Inside the nozzle hole, the needle 1 is accommodated so as to be capable of reciprocating in the axial direction.

A simple round hole-shaped guide hole is formed on the base end side of the nozzle hole, that is, inside the cylindrical needle guide of the nozzle body 2. Further, a fuel reservoir chamber having a hole diameter larger than that of the guide hole is provided at an intermediate portion of the nozzle hole. In this fuel reservoir chamber, for example, fuel is introduced through a fuel hole from a high pressure portion such as a high pressure fuel pump or a common rail.
The nozzle body 2 has a cylindrical portion that forms a fuel flow path communicating with the fuel reservoir chamber between the nozzle body 2 and the small-diameter shaft portion 30 of the needle 1. Further, the nozzle body 2 has a reduced diameter portion 18 between which the outer diameter gradually decreases from the edge line of the cylindrical portion toward the proximal end portion of the sack portion 10 between the sack portion 10 and the cylindrical portion. Yes.

The sack portion 10 of the nozzle body 2 is provided with a concave curved bottom surface 19 having a predetermined radius of curvature. The sack portion 10 is formed with a plurality of slit injection holes 8 and 9 that penetrate obliquely from the inner surface to the outer surface with respect to the nozzle axis (CL).
The plurality of slit nozzle holes 8 and 9 constitute a spray shape variable mechanism, and are provided so as to extend radially outward with respect to the nozzle axis (CL).
The plurality of slit nozzle holes 8 correspond to “first nozzle holes” in the claims.
The plurality of slit nozzle holes 9 correspond to “second nozzle holes” in the claims.

The plurality of slit injection holes 8 are first fuel injection holes (internal and external communication holes) that communicate the inner surface (first sack wall surface) on the proximal end side of the sack portion 10 and the outer surface of the sack portion 10. The slit nozzle holes 8 include a plurality of nozzle hole inlets 11 opened at the inner surface on the proximal end side of the sack portion 10, a plurality of nozzle hole outlets 12 opened at the outer surface on the proximal end side of the sack portion 10, and a plurality of nozzle holes. A plurality of nozzle hole channels 13 communicating the hole inlet 11 and the plurality of nozzle hole outlets 12 are provided.
The plurality of nozzle hole inlets 11 correspond to “first nozzle hole inlets” in the claims.
The plurality of nozzle hole outlets 12 correspond to “first nozzle hole outlets” in the claims.
The plurality of nozzle hole channels 13 correspond to “first nozzle hole channels” in the claims.

  Further, the plurality of slit injection holes 8 are formed along the circumferential direction of the sack portion 10 so that the fuel spray efficiently spreads into the combustion chamber of the cylinder of the engine. These slit nozzle holes 8 are formed in a plurality (five) at predetermined intervals (equal intervals) in the circumferential direction of the sack portion 10. The plurality of slit nozzle holes 8 have a length in a direction in which the opening shapes of the plurality of nozzle hole inlets 11, the plurality of nozzle hole outlets 12, and the plurality of nozzle hole channels 13 are orthogonal to the nozzle axis (CL). (A) exhibits a flat slit shape larger than the length (b) in the direction parallel to the nozzle axis (CL). The flat slit shape is a flat oval shape as shown in FIG.

The plurality of nozzle hole inlets 11 have a major axis in a direction perpendicular to the fuel flow line flowing from the fuel flow path 6 to the sac chamber 7 and parallel to the fuel flow line flowing from the fuel flow path 6 to the sac chamber 7. The direction is the minor axis. These nozzle hole inlets 11 are arranged at predetermined intervals (equal intervals) on the same circumference around the nozzle axis (CL) on the proximal end side of the sack portion 10.
The opening shape of the plurality of nozzle hole outlets 12 is a flat slit (oval) shape similar to the opening shape of the plurality of nozzle hole inlets 11.
The plurality of nozzle hole channels 13 are formed such that the opening shape or channel cross-sectional area of the plurality of nozzle hole inlets 11 gradually increases from the plurality of nozzle hole inlets 11 toward the plurality of nozzle hole outlets 12. .

The plurality of slit nozzle holes 9 are a plurality of second nozzle holes that connect the inner surface (first sack wall surface) on the distal end side of the sack portion 10 and the outer surface of the sack portion 10. These slit nozzle holes 9 include a plurality of nozzle hole inlets 21 opened at the inner surface on the tip side of the sack portion 10, a plurality of nozzle hole outlets 22 opened at the outer surface on the tip side of the sack part 10, and a plurality of nozzle hole inlets. A plurality of nozzle hole channels 23 communicating the nozzle 21 and the plurality of nozzle hole outlets 22 are provided.
The plurality of nozzle hole inlets 21 correspond to “second nozzle hole inlets” in the claims.
The plurality of nozzle hole outlets 22 correspond to “second nozzle hole outlets” in the claims.
The plurality of nozzle hole channels 23 correspond to “second nozzle hole channels” in the claims.

  Further, the plurality of slit injection holes 9 are formed along the circumferential direction of the sack portion 10 so that the fuel spray efficiently spreads into the combustion chamber of the cylinder of the engine. These slit nozzle holes 9 are formed in a plurality (five) at predetermined intervals (equal intervals) in the circumferential direction of the sack portion 10. The plurality of slit nozzle holes 9 have a length in a direction in which the opening shapes of the plurality of nozzle hole inlets 21, the plurality of nozzle hole outlets 22, and the plurality of nozzle hole channels 23 are orthogonal to the nozzle axis (CL). (A) exhibits a flat slit (ellipse) shape larger than the length (b) in the direction parallel to the nozzle axis (CL). This flat slit (oval) shape is a flat oval shape as shown in FIG.

The plurality of nozzle hole inlets 21 have a major axis in the direction orthogonal to the fuel flow line flowing from the fuel flow path 6 to the sac chamber 7 and parallel to the fuel flow line flowing from the fuel flow path 6 to the sac chamber 7. The direction is the minor axis. These nozzle hole inlets 21 are arranged at predetermined intervals (equal intervals) on the same circumference around the nozzle axis (CL) on the tip side of the sack portion 10.
The opening shape of the plurality of nozzle hole outlets 22 is a flat slit (oval) shape similar to the opening shape of the plurality of nozzle hole inlets 21.
The plurality of nozzle hole channels 23 are formed so that the opening shape or channel cross-sectional area of the plurality of nozzle hole inlets 21 gradually increases from the plurality of nozzle hole inlets 21 toward the plurality of nozzle hole outlets 22. .

[Features of Example 1]
Here, in FIG. 5 and FIG. 6, fuel is injected with the configuration shown in FIG. 1 to FIG. Are shown for each injection quantity.

  From FIG. 5 and FIG. 6, from the region (SS <(SH × N)) where the fuel injection amount is large (the valve opening period of the needle 1, that is, the fuel injection period is long) and the needle lift amount is relatively small. In the case of transition to the state 2 region where the needle lift amount is relatively large (SS> (SH × N)), the higher the fuel injection pressure, the more the fuel injected from the slit injection holes 8 and 9. It can be seen that the spray length increases and the penetration force increases.

  Further, when the fuel injection amount is small (the valve opening period of the needle 1, that is, the fuel injection period is short) and the fuel is injected only in the state 1 region, the slit can be increased even if the fuel injection pressure is increased. It can be seen that the spray length of the fuel injected from the nozzle holes 8 and 9 becomes shorter and the penetration force decreases. Here, SS is a flow passage sectional area of the fuel flow passage 6 formed between the seal portion 33 of the valve portion 3 of the needle 1 and the nozzle seat 5 of the nozzle body 2 when the needle is opened. SH is the total channel cross-sectional area of all the slit nozzle holes 8 and 9. N is the total number of nozzle holes of all the slit nozzle holes 8 and 10 (10 in Examples 1 and 2).

FIG. 7 shows the assumption of the principle for the effects shown in FIGS.
In the state 1 where the needle lift amount is small, the fuel is introduced into the sac 7 from the fuel flow path 6 on the upstream side of the sac chamber 7, and the fuel flow directly flowing into the slit nozzle holes 8 and 9 is strong. It occurs at the upper peripheral edge of the inlets 11 and 21.
In the fuel injection nozzle of the present embodiment, a flat slit (ellipse) shape can generate a large number of fuel separation portions, and the reduction rate of the flow passage cross-sectional area due to separation is large, and the higher the injection pressure is, the higher the flow velocity is. The applicant of the present application speculates that the tendency is remarkable. As a result, the penetration force is reduced.

On the other hand, in the state 2 where the needle lift amount is large and the fuel flow rate depends on the total nozzle hole area, the fuel flow toward the center of the nozzle axis (CL) of the nozzle body causes the slit nozzle hole 8 from the upper peripheral edge of the nozzle hole inlets 11 and 21. , 9 is weakened and it is difficult for the above-described separation to occur. Therefore, it is assumed that the penetration force does not decrease when the fuel injection period is long in the region depending on the total area of the injection holes.
In order to obtain the above effect, each specification satisfies the following arithmetic expressions (Equation 1, Equation 2, Equation 3).

[Equation 1]
60 ° ≦ θ ≦ 90 °... In order to positively generate separation, the angle at which fuel flows from the fuel flow path 6 on the upstream side of the sac chamber 7 into the slit nozzle holes 8 and 9 is reduced.
Here, θ is an intersection angle between the nozzle hole axis extending in the center line direction of each nozzle hole flow path 13, 23 of the plurality of slit nozzle holes 8, 9 and the tip direction of the nozzle axis (CL). That is, the crossing angle (θ) is a right angle or an acute angle close to a right angle of 60 degrees or more.

[Equation 2]
b <a ≦ Ls / N... The slit injection holes 8 and 9 have a flat slit (ellipse) shape so that they are greatly affected by fuel separation in the state 1 region.
That is, the opening shape of each of the nozzle inlets 11 and 21 of the plurality of slit nozzle holes 8 and 9 is a flat slit (oval) shape that satisfies the relationship of the arithmetic expression of [Equation 2].
Here, a is the length of the slit nozzle holes 8 and 9 in the direction parallel to the nozzle axis (CL), b is the length of the slit nozzle holes 8 and 9 in the direction orthogonal to the nozzle axis (CL), and Ls Is the circumferential length of the cross section of the sac chamber including the injection hole inlets 11 and 21, and N is the total number of nozzle holes in the cross section of the sac chamber (the number of nozzle holes of the slit nozzle hole 8 + the number of nozzle holes of the slit nozzle hole 9: Example 1 and 2 are 10).

[Equation 3]
dh> dn... Suppressing the flow of fuel in the direction of the nozzle axis so that in state 1 the fuel flows from the fuel flow path 6 upstream of the sac chamber 7 into the slit nozzle holes 8 and 9 at an acute angle. To. Here, dh is from the seal portion 33 of the needle 1 when the needle is fully closed to the intersection of the virtual nozzle hole axis and the nozzle axis (CL) extending straight in the direction of the center line of the nozzle hole channels 13 and 23. In the distance (axial distance), dn is a distance (axial distance) from the seal portion 33 of the needle 1 to the axial tip of the needle 1 (tip of the valve portion 3).

[Operation of Example 1]
Next, the operation of the injector provided with the fuel injection nozzle of this embodiment will be briefly described with reference to FIGS.

Here, when the ECU does not energize the first and second coils of the first and second solenoids, the valve portion 3 of the needle 1 is connected to the seat portion 17 of the nozzle body 2 as shown in FIG. The communication between the upstream fuel reservoir chamber and the downstream sack chamber 7 is blocked by the fuel flow path 6.
Therefore, the fuel injection nozzle is in a closed (full closed) state in which the needle 1 is closed, and fuel injection from the injection hole outlets 12 and 22 of the plurality of slit injection holes 8 and 9 into the combustion chamber of the engine is not performed. .

On the other hand, when the engine operating state is the first operating state, for example, in the first operating region where the engine load is relatively low, the needle lift amount is set to a relatively small state 1. For this reason, the ECU energizes (ON) only the first coil of the first solenoid. Thus, when only the first coil is turned on, the needle 1 and the first armature and the like stroke from the initial position (default position) to the proximal end side in the solenoid shaft direction.
Therefore, a region where the fuel injection rate depends on the needle lift amount is low, that is, the needle lift amount is set to a state 1 smaller than the state 2. At this time, the cross-sectional area of the fuel flow path 6 is smaller than that in the state 2.

  In the state 1 where the fuel injection rate depends on the needle lift amount and the needle lift amount is low, the fuel injected from the respective nozzle hole outlets 12 and 22 of the plurality of slit nozzle holes 8 and 9 into the combustion chamber of the engine cylinder A spray with a large diffusion angle and a high diffusion and a low penetration force can be obtained. In such a case, the flow path cross-sectional area of the fuel flow path becomes relatively small, and the fuel flow directly flowing from the fuel flow path 6 upstream of the sac chamber 7 directly into the slit nozzle holes 8 and 9 is strong. , 21 occurs in the upper periphery of the fuel.

And since the opening shape of each nozzle hole inlet 11 and 21 of the plurality of slit nozzle holes 8 and 9 is the above-described flat slit (ellipse) shape, in the state 1 region, that is, the fuel spray angle. When the fuel spray shape has a large diffusion and a low penetration force, it is possible to generate a relatively large number of fuel separation parts, and the flow path cross-sectional area is reduced by fuel separation. The higher the injection rate is, the higher the flow rate and the higher the injection pressure, the more prominent the tendency is, and it becomes possible to obtain fuel spray with high diffusion and a low penetration force with a large fuel spray angle.
Accordingly, the fuel is injected with high diffusion and low penetration force from the nozzle hole outlets 12 and 22 of the plurality of slit nozzle holes 8 and 9 toward the combustion chamber of the cylinder of the engine.

Further, when the command injection period elapses after the fuel injection into the combustion chamber of the engine cylinder is started, energization to the first coil of the first solenoid is stopped. Then, the first armature and the needle 1 move in the valve closing direction by the biasing force (spring load) of the first spring. As a result, the seal portion 33 of the valve portion 3 of the needle 1 is seated on the seat portion 17 of the nozzle body 2 and the communication between the upstream fuel reservoir chamber and the downstream sack chamber 7 by the fuel flow path 6 is blocked. .
Therefore, the fuel injection nozzle returns to the closed (fully closed) state in which the needle 1 is closed. Thus, fuel injection into the combustion chamber of the engine cylinder ends.

Further, in the second operation state where the engine operation state is the second operation state, for example, in the second operation region where the engine load is relatively high, the needle lift amount is set to a relatively large state 2. For this reason, the ECU energizes (ON) both the first and second coils of the first and second solenoids. Accordingly, when the first coil is turned on, the needle 1 and the first armature and the like stroke from the initial position (default position) to the proximal end side in the solenoid axis direction. When the second coil is turned on, the needle 1 and the second armature and the like stroke from the initial position (default position) to the proximal end side in the solenoid axis direction.
Therefore, when both the first coil and the second coil are turned on, the needle lift amount in which the fuel flow rate depends on the total nozzle hole cross-sectional area is high, that is, the needle lift amount is larger than that in the state 1. 2 is set. At this time, the cross-sectional area of the fuel flow path 6 is larger than that in the state 1.

  In the state 2 where the fuel flow rate depends on the total cross-sectional area of the nozzle hole and the needle lift amount is high, the fuel is injected from the nozzle hole outlets 12 and 22 of the plurality of slit nozzle holes 8 and 9 into the combustion chamber of the engine cylinder. A low diffusion and a high penetrating spray with a small fuel spray angle can be obtained. In such a case, the flow passage cross-sectional area of the fuel flow passage 6 becomes relatively large, and the fuel flow toward the center of the nozzle axis (CL) of the nozzle body 2 causes the injection hole flow passage from the upper peripheral edge of the injection hole inlets 11 and 21. The flow to 13 and 23 is weakened, and it is difficult for the fuel to peel off at the upper peripheral edge of the injection hole inlets 11 and 21.

And since the opening shape of each nozzle hole inlet 11 and 21 of the some slit nozzle holes 8 and 9 is the above-mentioned flat slit (ellipse) shape, it is the spray angle of a fuel at the time of the state 2 state. When the spray shape is small and low diffusion and high penetrating fuel spray can be obtained, if the fuel injection period is long in the region where the needle lift amount depending on the total cross-sectional area of the nozzle hole is high, the penetrating force is It is possible to obtain a fuel spray that does not decrease, has a low fuel spray angle, and has a low diffusion and a high penetration.
Therefore, fuel is injected with low diffusion and high penetration force from the injection hole outlets 12 and 22 of the plurality of slit injection holes 8 and 9 toward the combustion chamber of the engine cylinder.

When the command injection period elapses after the fuel injection into the combustion chamber of the engine cylinder is started, the energization of the first and second coils of the first and second solenoids is stopped. Then, the first and second armatures and the needle 1 move in the valve closing direction by the biasing force (spring load) of the first and second springs.
As a result, the seal portion 33 of the valve portion 3 of the needle 1 is seated on the seat portion 17 of the nozzle body 2 and the communication between the upstream fuel reservoir chamber and the downstream sack chamber 7 by the fuel flow path 6 is blocked. .
Therefore, the fuel injection nozzle returns to the closed (fully closed) state in which the needle 1 is closed. Thus, fuel injection into the combustion chamber of the engine cylinder ends.

[Effect of Example 1]
As described above, in the injector of the present embodiment, the opening shapes of the plurality of slit nozzle holes 8 and 9 formed along the circumferential direction of the sack portion 10 of the nozzle hole peripheral portion 4 of the nozzle body 2, particularly the plurality of nozzle holes. The opening shapes of the nozzle hole inlets 11 and 21, the plurality of nozzle hole outlets 12 and 22, and the plurality of nozzle hole flow paths 13 and 23 are flat slit (oval) shapes satisfying the relationship of b <a ≦ Ls / N. A fuel injection nozzle is provided.

  Thereby, although it is a simple structure which does not require a complicated process for forming the valve part 3 of the needle 1, the fuel injection rate depends on the needle lift amount. The fuel spray shape can be changed between the time and the time of the state 2 where the needle lift amount is high where the fuel flow rate depends on the total nozzle hole cross-sectional area. Specifically, the spray shape in state 1 is a low penetration / high diffusion spray, and the spray shape in state 2 is a high penetration / low diffusion spray.

As a result, the spray shape of the fuel injected from the plurality of slit injection holes 8 and 9 can be changed between the state 1 in the state 1 where the needle lift amount is low and the region 2 in the state 2 where the needle lift amount is high. The shape variable mechanism, that is, the spray shape variable mechanism for changing the fuel spray shape in the fuel injection nozzle, in particular, the plurality of slit injection holes 8 and 9 is relatively simple without requiring a complicated processing step. Can be realized.
Further, the fuel injection nozzle of this embodiment has a simple structure as compared with the fuel injection nozzles of the conventional examples 1 and 2, and can change the fuel spray shape at a constant injection pressure.

By the way, in an internal combustion engine (compression ignition type engine) such as a diesel engine, for the purpose of reducing nitrogen oxide (NOx) and combustion noise by improving a combustion state at low load such as idling and low-speed rotation. A small amount of minute injection (hereinafter referred to as pilot injection) is performed before the main injection that can be the combustion torque.
For example, in the fuel injection nozzle of the conventional example 1 (the nozzle of the conventional example 1 of the circular injection hole), when pilot injection is performed at the time of high pressure injection, when the state 2 with a relatively large needle lift is selected, There is a bug. When pilot injection is performed during high-pressure injection, the pressure in the combustion chamber of the engine cylinder is relatively small. Therefore, if the fuel spray shape is highly penetrating / low diffusion spray, the fuel spray from the nozzle hole is There is a problem that a good combustion state cannot be obtained because of hitting the combustion chamber wall of the cylinder.

Therefore, in the injector of this embodiment, a slit (oval) shape that is flat at an acute angle (60 ° ≦ θ ≦ 90 °) perpendicular to or perpendicular to the nozzle tip direction of the nozzle axis (CL) of the nozzle body 2. A fuel injection nozzle having a large number of slit injection holes 8 and 9 is employed.
Then, pilot injection is performed only in the state 1 in which the needle lift amount is relatively small, and after that, after the predetermined interval has elapsed, the main injection is performed in the states 1 and 2, so that at the time of high pressure injection (relatively high injection pressure) When the pilot injection is performed before the main injection at the same time, the penetration force of the fuel spray injected from the slit injection holes 8 and 9 into the combustion chamber of the cylinder can be suppressed as compared with the conventional example 1.

Therefore, even if the pressure in the combustion chamber of the engine cylinder is relatively small, the fuel spray shape is low penetration and high diffusion spray, so that the fuel spray from the plurality of slit injection holes 8 and 9 A good combustion state can be obtained without hitting the wall surface of the combustion chamber.
Moreover, because of the low penetrating spray, combustion can be performed in the air in the combustion chamber of each cylinder of the engine, and heat loss from which heat energy escapes can be reduced.
Further, by utilizing the spray characteristics shown in FIG. 6, fuel is injected from the plurality of slit injection holes 8 and 9 while keeping the fuel injection pressure constant at a high level and avoiding the adhesion of the combustion chamber wall surface of the engine cylinder at an early stage. Thus, the present invention can be applied to a diesel engine that selectively performs operation of homogeneous premixed auto-ignition combustion that forms a homogeneous mixture and diffusion combustion.

  If the opening shape of each nozzle hole inlet 11 and 21 of at least a plurality of slit nozzle holes 8 and 9 is a flat slit shape, a flat trapezoidal nozzle hole as shown in FIG. An inlet 41, a flat slit-shaped nozzle hole inlet 42 combining a flat rectangle as shown in FIG. 8B and two sets of squares, a flat rectangle 3 as shown in FIG. A flat slit-shaped nozzle hole inlet 43 combined with a set of squares, a flat slit-shaped nozzle hole inlet 44 combined with a flat rectangle as shown in FIG. You may adopt.

Also, a flat slit-shaped jet combining a flat rectangle (a horizontally long rectangle orthogonal to the nozzle axis (CL)) and a vertically long square parallel to the nozzle axis (CL) as shown in FIG. A hole inlet 45, a flat elliptical nozzle hole inlet 46 as shown in FIG. 8 (f), a flat triangular nozzle hole inlet 47 as shown in FIG. Absent. Furthermore, you may employ | adopt the flat slit shape which combined these selectively.
In addition, if the opening shape of each nozzle hole inlet 11 and 21 of several slit nozzle holes 8 and 9 is a flat slit shape, opening of each nozzle hole outlet 12 and 22 of several slit nozzle holes 8 and 9 will be described. The shape may be circular.

Next, the spray length of fuel injected from the circular injection hole of the fuel injection nozzle of Conventional Example 1 (hereinafter referred to as the nozzle of Conventional Example 1) and the slit injection of the fuel injection nozzle of Example 1 (hereinafter referred to as the nozzle of Example 1). Experiment 1 will be described in which the spray length of the fuel injected from the hole is compared.
In this experiment 1, the spray length of the fuel injected from the circular nozzle hole of the nozzle of the conventional example 1 (characteristic line in the case of the conventional nozzle hole: the broken line in the figure) and the slit nozzle hole of the nozzle of the first example are injected. The fuel spray length (characteristic line in the case of the slit nozzle hole: solid line in the figure) was compared and investigated, and the experimental result is shown in the graph of FIG.
Here, the circular nozzle hole of the nozzle of Conventional Example 1 is a plurality of nozzle hole inlets formed along the circumferential direction of the inner surface of the sack portion of the nozzle body, and the circumferential direction of the outer surface of the sack portion of the nozzle body. A plurality of nozzle hole outlets formed along the plurality of nozzle hole channels from a plurality of nozzle hole inlets to a plurality of nozzle hole outlets are circular nozzle holes.

Next, the spray volume of the fuel injected from the circular injection hole of the fuel injection nozzle of Conventional Example 1 (hereinafter referred to as the nozzle of Conventional Example 1) and the slit injection of the fuel injection nozzle of Example 1 (hereinafter referred to as the nozzle of Example 1). Experiment 1 will be described, in which the spray volume of fuel injected from the holes 8 and 9 is comparatively investigated.
This experiment 1 is based on the spray volume of fuel injected from the circular nozzle hole of the nozzle of the conventional example 1 (characteristic line in the case of the conventional nozzle hole: broken line in the figure) and the slit nozzle holes 8 and 9 of the nozzle of the first example. This is a comparative investigation of the spray volume of fuel to be injected (characteristic line in the case of slit nozzle holes: solid line in the figure), and the experimental results are shown in the graph of FIG.
From the graphs of FIGS. 9 and 10, the fuel spray injected from the slit nozzle holes 8 and 9 of the nozzle of Example 1 has a lower fuel spray penetration force and an increased spray volume than the conventional nozzle. Thus, the combustion state in the combustion chamber of the cylinder of the engine is improved, so that exhaust emission can be reduced.

[Configuration of Example 2]
FIG. 11 shows an injector (Embodiment 2) to which the fuel injection valve of the present invention is applied. Here, the same reference numerals as those in the first embodiment indicate the same configuration or function, and the description thereof is omitted.

As in the first embodiment, the injector according to the present embodiment is installed outside the nozzle body 2 of the fuel injection nozzle that injects fuel into the combustion chamber formed in the cylinder of the engine, and the needle 1. And a needle lift amount variable mechanism capable of changing the lift amount.
The fuel injection nozzle is formed between a needle 1 having a substantially two-stage conical surface-shaped valve portion 3 on the tip side, and between the valve portion 3 of the needle 1 and the conical surface-shaped nozzle seat 5 when the needle is opened. An annular fuel passage 6, provided downstream of the fuel passage 6 in the fuel flow direction, a sac chamber 7 communicating with the fuel passage 6, and provided downstream of the sac chamber 7 in the fuel flow direction. And a nozzle body 2 having a plurality of slit nozzle holes 8 and 9 communicating with the sac chamber 7 and having a needle 1 for opening and closing the plurality of slit nozzle holes 8 and 9.

The plurality of slit nozzle holes 8 and 9 are similar to the first embodiment in that the opening shapes of the plurality of nozzle hole inlets 11 and 21, the plurality of nozzle hole outlets 12 and 22, and the plurality of nozzle hole channels 13 and 23 are b < It exhibits a flat slit shape that satisfies the relationship of a ≦ Ls / N.
The opening shape of the plurality of nozzle hole inlets 11 and 21 has a flat oval shape in which the length in the direction orthogonal to the nozzle axis (CL) is larger than the length in the direction parallel to the nozzle axis (CL). . Moreover, the opening shape of the some nozzle hole exits 12 and 22 exhibits the flat oval shape same as the opening shape of the some nozzle hole inlets 11 and 21. As shown in FIG.
In addition, unlike the first embodiment, the plurality of nozzle hole channels 13 and 23 have an opening shape of the plurality of nozzle hole inlets 11 and 21 from the plurality of nozzle hole inlets 11 and 21 to the plurality of nozzle hole outlets 12 and 22. Alternatively, it is formed so as to maintain the cross-sectional area of the flow path.
As described above, the injector of the present embodiment has the same effects as those of the first embodiment.

[Modification]
In this embodiment, the fuel injection valve according to the present invention is applied to an injector provided with a fuel injection nozzle that injects fuel into a cylinder of an engine using high-pressure fuel accumulated in the common rail. The fuel is directly pumped into the fuel reservoir chamber from a fuel injection pump such as a row type fuel injection pump or a distributed fuel injection pump, and the fuel pressure (nozzle opening force) in the fuel reservoir chamber is spring ( When the pressure exceeds the urging force of the spring) (the axial force in the valve closing direction: nozzle closing force), the needle opens and the fuel injection nozzle used in the fuel injection device that injects fuel into the cylinder of the engine You may apply to the provided fuel injection valve.

  In this embodiment, the lift amount of the needle 1 is changed between a first state (state 1) in which the needle lift amount is relatively small and a second state (state 2) in which the needle lift amount is relatively large. Although two sets of first and second solenoids (actuators) are employed as the actuator of the variable amount mechanism, the displacement of the first and second piezo stacks due to the expansion and contraction of the needle 1 is changed as the actuator of the variable needle lift amount mechanism. A piezo actuator that changes the lift amount of the needle 1 between a first state (state 1) in which the needle lift amount is relatively small and a second state (state 2) in which the needle lift amount is relatively large. It may be adopted.

Further, the needle lift amount variable mechanism that changes the lift amount of the needle 1 between a first state (state 1) in which the needle lift amount is relatively small and a second state (state 2) in which the needle lift amount is relatively large. As the actuator, an electric actuator provided with a conversion mechanism that converts the rotational motion of the rotating shaft driven by the motor into the linear motion of the needle 1 may be employed.
Further, an nozzle hole penetrating the tip wall portion (circular top portion) of the nozzle body 2 in the axial direction may be provided on one end side (tip side) of the nozzle body 2 in the axial direction.
The plurality of nozzle hole inlets 11 and 21, the plurality of nozzle hole outlets 12 and 22 and the plurality of nozzle hole channels 13 and 23 have the same opening shape, but between the plurality of first and second nozzle holes. The channel cross-sectional areas may be different, and the opening shapes of the plurality of first and second nozzle holes may be different from each other.

The fuel injection valve provided with the fuel injection nozzle of the present invention may be applied to a fuel injector that directly injects fuel into a cylinder of an internal combustion engine such as a gasoline engine.
Moreover, although the total number of nozzle holes of the slit nozzle holes 8 and 9 is 10, the total number of nozzle holes of the slit nozzle holes 8 and 9 may be 2 to 20. Further, the plurality of nozzle holes are divided into two first and second nozzle hole groups (a plurality of slit nozzle holes 8 and 9) arranged at predetermined intervals (equal intervals) on the same circumference. The plurality of nozzle holes may be one nozzle hole group (a plurality of slit nozzle holes) arranged at predetermined intervals (equal intervals) on the same circumference.

In the first state (state 1) where the needle lift amount is relatively small, only the slit nozzle hole 9 on the tip side of the sack portion 10 is opened, and the needle lift amount is relatively large in the second state (state 2). ), Both the slit nozzle holes 8 on the proximal end side of the sack portion 10 and the slit nozzle holes 9 on the distal end side of the sack portion 10 may be opened.
Moreover, if the arrangement | positioning which can use the nozzle hole peripheral part 4 of the nozzle body 2 without intensity | strength damage is possible, 4-20 pieces of the total nozzle holes of the slit nozzle hole are appropriate.

DESCRIPTION OF SYMBOLS 1 Needle 2 Nozzle body 3 Needle valve part 4 Nozzle body peripheral part 5 Nozzle seat (sheet surface)
6 Fuel flow path 7 Suck chamber 8 Slit nozzle hole (first nozzle hole)
9 Slit nozzle hole (second nozzle hole)
10 Sack club

Claims (13)

A fuel injection valve for injecting fuel into a cylinder of an internal combustion engine,
(A) a needle (1) having a valve part (3) on one end side;
(B) The lift amount of the needle (1) is changed between a first state where the lift amount of the needle (1) is relatively small and a second state where the lift amount of the needle (1) is relatively large. Possible needle lift amount variable mechanism,
(C) The valve portion (3) can be seated when the needle (1) is closed, and an annular fuel flow path (6) is formed between the valve portion (3) and the needle (1) when the needle (1) is opened. ) Forming a seat surface (5), a bottomed cylindrical sac portion (10) forming a sac chamber (7) communicating with the fuel flow path (6) when the needle (1) is opened, and A cylindrical nozzle body (2) having a plurality of injection holes (8, 9) that communicate with the sac chamber when the needle (1) is opened and that communicate with the inside and outside of the sac part through the sac part In a fuel injection valve equipped with
The plurality of nozzle holes (8, 9) have a plurality of nozzle hole inlets (11, 21) opened at the inner surface of the sack portion (10), and at least the plurality of nozzle hole openings (11, 21). The opening shape is
The circumferential length of the cross section of the sac chamber including the plurality of nozzle hole inlets (11, 21) is Ls,
The number of nozzle holes in the cross section of the sac chamber is N,
The length in the direction orthogonal to the nozzle axis (CL) extending in the center line direction of the nozzle body (2) is a,
When the length in the direction parallel to the nozzle axis (CL) is b,
b <a ≦ Ls / N
A fuel injection valve characterized by exhibiting a flat slit shape that satisfies the above relationship. The fuel injection valve according to claim 1, wherein
The plurality of nozzle holes (8, 9) extend from the plurality of nozzle hole inlets (11, 21) to the plurality of nozzle hole outlets (12, 22) opened on the outer surface of the sack portion (10). Nozzle hole channels (13, 23)
The nozzle hole axis extending in the center line direction of the plurality of nozzle hole channels (13, 23) has an acute angle close to a right angle or a right angle of 60 degrees or more with respect to the tip direction of the nozzle axis (CL). A fuel injection valve characterized by crossing at The fuel injection valve according to claim 1 or 2,
The fuel injection valve according to claim 1, wherein the seat surface (5) includes an annular seat portion (17) on which the valve portion (3) is seated when the needle (1) is closed. In the fuel injection valve according to any one of claims 1 to 3,
The needle (1) has an annular seal portion (33) seated on the seat surface (5) when the needle (1) is closed on the outer periphery of the valve portion (3). Fuel injection valve. The fuel injection valve according to claim 4, wherein
The plurality of nozzle holes (8, 9) extend from the plurality of nozzle hole inlets (11, 21) to the plurality of nozzle hole outlets (12, 22) opened on the outer surface of the sack portion (10). Nozzle hole channels (13, 23)
From the seal part (33) when the needle (1) is fully closed to the intersection of the virtual nozzle hole axis extending in the center line direction of the nozzle hole channel (13, 23) and the nozzle axis (CL) And the distance of dh
When the distance from the seal portion (33) to the tip of the needle (1) in the axial direction is dn,
dh> dn
A fuel injection valve characterized by satisfying the relationship In the fuel injection valve according to any one of claims 1 to 5,
The plurality of nozzle holes (8, 9) have a plurality of nozzle hole outlets (12, 22) opened at the outer surface of the sack portion (10),
The opening shapes of the plurality of nozzle hole inlets (11, 21) are flat such that the length in the direction orthogonal to the nozzle axis (CL) is larger than the length in the direction parallel to the nozzle axis (CL). It exhibits a slit shape, and the opening shape of the plurality of nozzle hole outlets (12, 22) exhibits a flat slit shape that is the same as or similar to the opening shape of the plurality of nozzle hole inlets (11, 21). A fuel injection valve. The fuel injection valve according to claim 6, wherein
The plurality of nozzle holes (8, 9) are a plurality of nozzle hole channels (13, 23) extending from the plurality of nozzle hole inlets (11, 21) to the plurality of nozzle hole outlets (12, 22). Have
The plurality of nozzle hole channels (13, 23) are formed from the plurality of nozzle hole inlets (11, 21) toward the plurality of nozzle hole outlets (12, 22). The fuel injection valve is characterized in that the opening shape or the cross-sectional area of the flow path increases gradually. The fuel injection valve according to claim 6, wherein
The plurality of nozzle holes (8, 9) are a plurality of nozzle hole channels (13, 23) extending from the plurality of nozzle hole inlets (11, 21) to the plurality of nozzle hole outlets (12, 22). Have
The plurality of nozzle hole channels (13, 23) extend from the plurality of nozzle hole inlets (11, 21) to the plurality of nozzle hole outlets (12, 22). The fuel injection valve is formed so as to maintain the opening shape or the cross-sectional area of the flow path. The fuel injection valve according to any one of claims 1 to 8,
The plurality of nozzle holes (8, 9) pass through the base end side of the sac portion (10) and communicate with the inside and outside of the base end side of the sack portion (10). And a plurality of second injection holes (9) penetrating the distal end side of the sac portion (10) and communicating with the inside and outside of the distal end side of the sac portion (10). valve. The fuel injection valve according to claim 9, wherein
The plurality of first nozzle holes (8) have a plurality of first nozzle hole inlets (11) opened at an inner surface on the proximal end side of the sack portion (10), and at least the plurality of first nozzle hole inlets. The fuel injection valve according to (11), wherein the opening shape has the flat slit shape. The fuel injection valve according to claim 9 or 10,
The plurality of second injection holes (9) have a plurality of second injection hole inlets (21) opened at the inner surface of the sack portion (10) on the front end side, and at least the plurality of second injection hole inlets ( 21) The fuel injection valve, wherein the opening shape of 21) exhibits the flat slit shape. The fuel injection valve according to any one of claims 1 to 11,
The flat slit shape is a flat oval shape, a flat elliptical shape, or a flat rectangular shape,
The plurality of nozzle hole inlets (11, 21) has a long axis, a long diameter, or a long side in a direction perpendicular to a fuel flow line flowing from the fuel flow path (6) into the sac chamber (7). A fuel injection valve characterized in that a direction parallel to a fuel flow line flowing from the flow path (6) into the sac chamber (7) is a short axis, a short diameter, or a short side. The fuel injection valve according to any one of claims 1 to 12,
A fuel injection nozzle for injecting fuel into the cylinder of the internal combustion engine;
The fuel injection nozzle includes the plurality of injection holes (8, 9), the sac chamber (7) communicating with the injection holes (8, 9), and a fuel passage (6) communicating with the sac chamber (7). The nozzle body (2) containing the needle (1) for opening and closing the plurality of nozzle holes (8, 9),
The fuel injection valve according to claim 1, wherein the variable needle lift amount mechanism is installed outside the nozzle body (2).

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