JP2010065561A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device for quickly operating a fuel injection valve. <P>SOLUTION: This fuel injection device includes a nozzle body 40 and an injection control valve 20 for advancing and retreating in a first fuel storage chamber 41. The injection control valve 20 communicates a first fuel passage 51 with the first fuel storage chamber 41, and cuts off the first fuel storage chamber 41 and a third fuel passage 53, by advancing up to a first position, and cuts off the first fuel passage 51 and the first fuel storage chamber 41, and communicates the first fuel storage chamber 41 with the third fuel passage 53, by retreating up to a second position. The injection control valve 20 includes a substantially columnar guide part 22 having an outside diametrical dimension D<SB>1</SB>, a substantially disk-like collar-shaped diametrically expanded part 23 having an outside diametrical dimension D<SB>2</SB>, and a substantially columnar closing part 24 having an outside diametrical dimension D<SB>3</SB>. The diametrically expanded part 23, the guide part 22 and the closing part 24 are formed so as to become small in order of the outside diametrical dimension D<SB>2</SB>of the diametrically expanded part 23, the outside diametrical dimension D<SB>1</SB>of the guide part 22 and the outside diametrical dimension D<SB>3</SB>of the closing part 24. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel injection device. Specifically, the present invention relates to a fuel injection device that is used in a diesel engine and injects fuel supplied at a high pressure from a fuel supply source.

Conventionally, fuel injection devices that inject fuel are used for diesel engines.
FIG. 6 is a cross-sectional view of a fuel injection device 701 according to a conventional example.
The fuel injection device 701 has a first fuel storage chamber 741, a second fuel storage chamber 742, a needle valve closing chamber 743, and an injection hole 745 extending from the second fuel storage chamber 742 to the outside of the fuel injection device 701. The nozzle body 740, the needle valve 710 held by the needle valve holding portion 746 inside the nozzle body 740, the closing auxiliary piston 730 provided inside the needle valve closing chamber 743 of the nozzle body 740, and the nozzle body 740 And an injection control valve 720 that is held by the injection control valve holding part 744 and can advance and retreat in the first fuel storage chamber 741.

  The nozzle body 740 includes a first fuel passage 751 extending from the fuel supply source to the first fuel storage chamber 741, a second fuel passage 752 extending from the first fuel storage chamber 741 to the second fuel storage chamber 742, and a first fuel storage chamber. A third fuel passage 753 from 741 to the needle valve closing chamber 743 and a fourth fuel passage 754 from the needle valve closing chamber 743 to the low pressure portion outside the fuel injection device are formed.

The injection control valve 720 communicates with the first fuel passage 751 and the first fuel storage chamber 741 by moving forward to the first position, and shuts off the first fuel storage chamber 741 and the third fuel passage 753. By retracting to the second position, the first fuel passage 751 and the first fuel storage chamber 741 are blocked, and the first fuel storage chamber 741 and the third fuel passage 753 are communicated.
The injection control valve 720 includes a substantially cylindrical guide portion 722 that can slide in the injection control valve holding portion 744, and a substantially disk-shaped bowl-shaped enlarged diameter portion 723 that is provided on the distal end side of the guide portion 722. And a substantially cylindrical closing portion 724 provided on the distal end side of the enlarged diameter portion 723. The outer diameter of the outer diameter and the closing portion 724 of the guide portion 722, and has a equal D _1.

  The needle valve 710 moves forward and is seated on the nozzle body 740, thereby blocking the second fuel storage chamber 742 and the injection hole 745, and retreating and separating from the nozzle body 740, thereby 742 and the nozzle hole 745 are communicated.

The operation of the fuel injection device 701 is as follows.
Fuel is supplied to the first fuel passage 751 from the fuel supply source. In this state, when the injection control valve 720 is advanced to the first position, the first fuel passage 751 and the first fuel storage chamber 741 communicate with each other, and the first fuel storage chamber 741 and the third fuel passage 753 are blocked. Is done. Therefore, fuel flows from the first fuel passage 751 through the first fuel storage chamber 741 and the second fuel passage 752 into the second fuel storage chamber 742, and the fuel pressure in the second fuel storage chamber 742 increases. Then, due to the fuel pressure in the second fuel storage chamber 742, the needle valve 710 moves backward and separates from the nozzle body 740. As a result, the fuel in the second fuel storage chamber 742 is injected from the injection hole 745.

On the other hand, when the injection control valve 720 is retracted to the second position, the first fuel passage 751 and the first fuel storage chamber 741 are blocked, and the first fuel storage chamber 741 and the third fuel passage 753 communicate with each other. . Therefore, fuel flows from the second fuel passage 752 through the first fuel storage chamber 741 and the third fuel passage 753 into the needle valve closing chamber 743, and the fuel pressure in the needle valve closing chamber 743 increases. Then, due to the fuel pressure in the needle valve closing chamber 743, the closing assist piston 730 moves forward, and pushes the needle valve 710 forward. As a result, the needle valve 710 is seated on the nozzle body 740 and fuel injection stops.
Japanese Patent Application No. 2008-159266

  As described above, in the conventional fuel injection device 701, when the injection control valve 720 is moved from the first position to the second position, the closing assist piston 730 moves forward, and the needle valve 710 is seated on the nozzle body 740, Fuel injection stops. Therefore, in order to control the fuel injection by the fuel injection device 701 with high accuracy, it is required to operate the injection control valve 720 quickly.

  An object of this invention is to provide the fuel-injection apparatus which can operate an injection control valve rapidly.

The fuel injection device of the present invention (for example, a fuel injection device 1 described later) includes a first fuel storage chamber (for example, a first fuel storage chamber 41 described later) and a second fuel storage chamber (for example, a second fuel storage described later). Chamber 42), a third fuel storage chamber (for example, a needle valve closing chamber 43 described later), and a nozzle hole (for example, a nozzle hole 45 described later) extending from the second fuel storage chamber to the outside of the fuel injection device. A needle valve (for example, a later-described needle valve 10) held by a nozzle body (for example, a later-described nozzle body 40) and a needle valve retaining portion (for example, a later-described needle valve retaining portion 46) inside the nozzle body. And a needle valve opening means (for example, a second fuel storage chamber 42, a stepped portion 13 and a fuel reservoir, which will be described later) provided on the tip side of the needle valve holding portion inside the nozzle body and having the second fuel storage chamber. 421) and needle valve closing means (for example, a needle valve closing chamber 43 and a closing auxiliary piston 30 to be described later) provided on the base end side of the needle valve holding portion inside the nozzle body and having the third fuel storage chamber. ) And an injection control valve (e.g., injection control described later) that is held by an injection control valve holding unit (e.g., injection control valve holding unit 44 described later) inside the nozzle body and can advance and retreat in the first fuel storage chamber. 20), and the nozzle body includes a first fuel passage (for example, a first fuel passage 51 described later) from a fuel supply source to the first fuel storage chamber, and the first fuel storage chamber from the first fuel storage chamber. A second fuel passage (for example, a second fuel passage 52 described later) reaching the second fuel storage chamber; a third fuel passage (for example, a third fuel described later) extending from the first fuel storage chamber to the third fuel storage chamber; Passage 53), And a fourth fuel passage (for example, a later-described fourth fuel passage 54) extending from the third fuel storage chamber to a low pressure portion outside the fuel injection device is formed, and the injection control valve is disposed in the injection control valve holding portion. And a substantially cylindrical guide portion (for example, a guide portion 22 to be described later) having a _first outer diameter dimension (for example, an outer diameter size D ₁ to be described later), and a distal end side of the guide portion. A substantially disc-shaped bowl-shaped enlarged portion (for example, a later-described enlarged portion 23) having a _second outer diameter dimension (for example, an outer diameter dimension D ₂ described later), and a tip of the expanded diameter portion A substantially cylindrical closing part (for example, a closing part 24 described later) provided on the side and having a third outer diameter dimension (for example, an outer diameter dimension D ₃ described later), the injection control valve, By moving forward to a first position (for example, a first position to be described later), the first fuel is stored on the front end side of the closing portion. The passage leading to the third fuel passage of the chamber is shut off and retracted to a second position (for example, a second position described later), whereby the first fuel in the first fuel storage chamber on the proximal end side of the enlarged diameter portion. The passage leading to the passage is shut off, and the needle valve moves forward and sits on the nozzle body, thereby shutting off the second fuel storage chamber and the injection hole and moving backward to separate from the nozzle body. Thus, the second fuel storage chamber communicates with the nozzle hole, the needle valve opening means retreats the needle valve by the fuel pressure in the second fuel storage chamber, and the needle valve closing means The needle valve is advanced by the fuel pressure in the third fuel storage chamber, and the second outer diameter dimension of the enlarged diameter part, the first outer diameter dimension of the guide part, and the third outer diameter dimension of the closing part are It is characterized by decreasing in order.

According to the present invention, the operation of the fuel injection device is as follows.
That is, fuel is supplied from the fuel supply source to the first fuel passage. When the injection control valve is advanced to the first position in this state, the first fuel passage and the first fuel storage chamber communicate with each other, and the first fuel storage chamber and the third fuel passage are blocked. Therefore, fuel flows from the first fuel passage through the first fuel storage chamber and the second fuel passage into the second fuel storage chamber, and the fuel pressure in the second fuel storage chamber increases. Then, the needle valve opening means operates, and the needle valve is retracted by the fuel pressure in the second fuel storage chamber and is separated from the nozzle body. Thereby, the fuel in the second fuel storage chamber is injected from the injection hole.

  On the other hand, when the injection control valve is retracted to the second position, the first fuel passage and the first fuel storage chamber are shut off, and the first fuel storage chamber and the third fuel passage communicate with each other. Therefore, fuel flows from the second fuel passage through the first fuel storage chamber and the third fuel passage into the third fuel storage chamber, and the fuel pressure in the third fuel storage chamber increases. Then, the needle valve closing means operates, and the needle valve advances by the fuel pressure in the third fuel storage chamber. As a result, the needle valve is seated on the nozzle body, and fuel injection stops.

Here, the first outer diameter dimension of the guide portion is made larger than the third outer diameter dimension of the closing portion. Therefore, in the state where the injection control valve is located at the first position, the total pressure received in the backward direction from the fuel in the first fuel storage chamber by the injection control valve is larger than the total pressure received in the forward direction. Accordingly, as a result, a reverse force acts on the injection control valve.
That is, in the state where the injection control valve is located at the first position, a force from the fuel in the first fuel storage chamber toward the second position acts on the injection control valve, so that the transition from the first position to the second position is performed. This facilitates the operation of the injection control valve quickly.

  In this case, an actuator (for example, an actuator 60 to be described later) that is provided on the base end side of the injection control valve holding portion of the injection control valve and can load the injection control valve in the forward direction, and the injection control valve It is preferable to include an elastic member (for example, a spring 21 described later) that biases in the backward direction.

According to the present invention, since the elastic member that urges the injection control valve in the backward direction is provided, the elastic control member moves the injection control valve toward the second position in a state where the injection control valve is positioned at the first position. Therefore, it is possible to move from the first position to the second position more quickly.
Further, if the reverse speed of the injection control valve is maintained at the same level as that of the conventional case, a force in the reverse direction acts on the injection control valve from the fuel in the first fuel storage chamber. Can be reduced. That is, the elastic member can be reduced in size.

  In this case, when the injection control valve shifts from the first position to the second position, the fuel in the first fuel storage chamber is transferred to the third fuel passage, the third fuel storage chamber, and the fourth fuel storage chamber. It is preferable to provide outflow suppressing means (for example, a closing auxiliary piston 30 and a needle valve closing chamber 43, which will be described later) for suppressing the flow out of the fuel injection device through the fuel passage.

  According to this invention, when the injection control valve shifts from the first position to the second position, the fuel in the second fuel passage flows into the first fuel storage chamber. Since the fuel in the chamber can be prevented from flowing out of the fuel injection device through the third fuel passage, the third fuel storage chamber, and the fourth fuel passage, the amount of fuel flowing out can be reduced. The overall efficiency of the fuel supply system can be improved.

  In this case, the needle valve closing means includes a closing auxiliary piston (for example, a closing auxiliary piston 30 to be described later) provided so as to be able to advance and retreat in the third fuel storage chamber, and the closing auxiliary piston has a last retracted position (to be described later). The third fuel passage and the third fuel storage chamber are shut off at the last retreat position), and the third fuel passage and the third fuel storage chamber are communicated with each other by shifting to a forward state. The fuel storage chamber has a closed auxiliary pressure chamber (for example, a closed auxiliary pressure chamber 432 described later) communicated with the third fuel passage by the closed auxiliary piston and the fourth fuel passage in the advanced state of the closed auxiliary piston. And a return pressure chamber (for example, a return pressure chamber 433 described later) communicating with each other, and the closing auxiliary piston applies a pressing force due to fuel pressure in the closing auxiliary pressure chamber to the needle valve. The closing auxiliary piston is moved from the advanced state to the last retracted position and shuts off the third fuel passage and the closing auxiliary pressure chamber, thereby the first fuel. Suppressing the fuel in the storage chamber from flowing into the third fuel storage chamber through the third fuel passage, thereby preventing the fuel in the first fuel storage chamber from flowing out of the fuel injection device. It is preferable that it is the outflow suppression means to suppress.

  According to this invention, the closing auxiliary piston transmits the pressing force by the fuel pressure in the closing auxiliary pressure chamber to the needle valve in the forward direction, and the needle valve is advanced to stop the fuel injection. Therefore, the closing speed of the needle valve can be improved, and the falling characteristic of the fuel injection pressure can be improved.

  In this case, the injection control valve is retracted from the first position, the second fuel passage and the third fuel passage are communicated, and the fuel pressure in the second fuel storage chamber and the third fuel storage chamber The force for moving the needle valve forward by the needle valve closing means in a state where the fuel pressure is equal is preferably larger than the force for moving the needle valve backward by the needle valve opening means.

  According to the present invention, in the state where the fuel pressure in the second fuel storage chamber and the fuel pressure in the third fuel storage chamber are equal, the force for advancing the needle valve by the needle valve closing means is applied to the needle valve by the needle valve opening means. Greater than the force to reverse. Therefore, when stopping the fuel injection, the fuel pressure acts in a direction to advance the needle valve, so that the fuel injection can be stopped quickly. Therefore, the response time from when the injection control valve is retracted to when fuel injection stops can be shortened. As a result, since the minimum injection time can be further shortened and the minimum injection amount can be reduced, various injection methods can be realized.

  The fuel injection device of the present invention includes a nozzle body in which a first fuel storage chamber is formed, and an injection control valve that is held inside the nozzle body and can advance and retreat in the first fuel storage chamber. The body includes a first fuel passage from a fuel supply source to the first fuel storage chamber, and an injection fuel passage from the first fuel storage chamber to the injection hole (for example, a second fuel passage 52 and a second fuel storage to be described later). Chamber 42), and a return fuel passage (for example, a third fuel passage 53, a needle valve closing chamber 43, and a fourth fuel passage 54, which will be described later) from the first fuel storage chamber to the low pressure portion outside the fuel injection device. The injection control valve is provided on the distal end side of the guide portion and a substantially cylindrical guide portion slidable in the injection control valve holding portion and having a first outer diameter. A substantially disk shape having a second outer diameter And a substantially cylindrical closing portion having a third outer diameter provided on the distal end side of the enlarged diameter portion, and the injection control valve is advanced to the first position. Thus, the communication portion that reaches the return fuel passage of the first fuel storage chamber is shut off at the distal end side of the second closing portion, and retracted to the second position, whereby the proximal end side of the first closing portion is The communication portion that reaches the first fuel passage of the first fuel storage chamber is blocked, the second outer diameter of the enlarged diameter portion, the first outer diameter of the guide portion, and the third outer diameter of the closing portion. It is characterized by decreasing in order of diameter.

  According to the present invention, in the state where the injection control valve is positioned at the first position, the force from the fuel in the first fuel storage chamber toward the second position acts on the injection control valve. It becomes easy to shift to the position, and the injection control valve can be operated quickly.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a configuration of a fuel injection device 1 according to an embodiment of the present invention. In the following FIGS. 1 to 5, the movement stroke amounts and dimensions of the needle valve 10, the injection control valve 20, and the closing assist piston 30 are exaggerated from the actual one for easy understanding.

The fuel injection device 1 is accommodated in a housing (not shown), and injects fuel supplied at a high pressure from a fuel supply source in accordance with the operation of the piezoelectric actuator 60.
This fuel injection device 1 includes a needle valve 10, an injection control valve 20, a spring 21 as an elastic member that urges the injection control valve, a closing auxiliary piston 30 as a needle valve closing means, and this closing auxiliary piston. A spring 31 that biases 30 and a substantially cylindrical nozzle body 40 that accommodates the spring 31.

  The nozzle body 40 is composed of three members, and the nozzle body 40 includes a first fuel storage chamber 41, a needle valve closing means, and a third fuel in order from the proximal end side to the distal end side. A needle valve closing chamber 43 as a storage chamber and a second fuel storage chamber 42 as a needle valve opening means are formed.

The nozzle body 40 includes a first fuel passage 51 extending from a fuel supply source (not shown) to the first fuel storage chamber 41, a second fuel passage 52 extending from the first fuel storage chamber 41 to the second fuel storage chamber 42, A third fuel passage 53 extending from the one fuel storage chamber 41 to the needle valve closing chamber 43 and a fourth fuel passage 54 extending from the needle valve closing chamber 43 to a low pressure portion (not shown) outside the nozzle body 40 are formed.
Here, examples of the fuel supply source include a high-pressure pump connected via a common rail.
Examples of the low pressure section include a fuel tank, a fuel passage between the low pressure pump and the high pressure pump, and a fuel passage upstream of the pressurizing chamber in the high pressure pump.

The first fuel storage chamber 41 is a substantially cylindrical space extending along the extending direction of the nozzle body 40.
A through hole having a circular cross section reaching the base end surface of the nozzle body 40 is formed in the base end surface of the first fuel storage chamber 41, and this through hole includes an injection control valve holding portion 44 that holds the injection control valve 20 and It has become.
The inner diameter of the injection control valve holding portion 44 is smaller than the inner diameter of the first fuel storage chamber 41, whereby a step portion 411 is formed on the base end surface of the first fuel storage chamber 41.

  The first fuel passage 51 extends from the proximal end surface of the nozzle body 40 to the inner peripheral surface on the distal end side of the through hole that is the injection control valve holding portion 44.

The needle valve closing chamber 43 is a substantially cylindrical space extending along the extending direction of the nozzle body 40. A stepped portion 431 is formed on the distal end side of the needle valve closing chamber 43 along the circumferential direction.
The third fuel passage 53 is a through hole that extends from approximately the center of the distal end surface of the first fuel storage chamber 41 to approximately the center of the proximal end surface of the needle valve closing chamber 43.
The fourth fuel passage 54 extends from the inner peripheral surface on the distal end side of the needle valve closing chamber 43 to the proximal end surface of the nozzle body 40.

The second fuel storage chamber 42 is a substantially cylindrical space extending along the extending direction of the nozzle body 40.
A through hole extending to the outside of the nozzle body 40 is formed on the distal end side of the second fuel storage chamber 42, and this through hole is a nozzle hole 45.
On the proximal end side in the extending direction of the second fuel storage chamber 42, a fuel reservoir portion 421 is formed as a needle valve opening means whose inner periphery is expanded.

A through hole from the needle valve closing chamber 43 to the second fuel storage chamber 42 is formed in the nozzle body 40, and this through hole serves as a needle valve holding portion 46 that holds the needle valve 10.
The second fuel passage 52 extends from the inner peripheral surface of the portion on the tip side of the step portion 411 of the first fuel storage chamber 41 to the fuel reservoir portion 421 of the second fuel storage chamber 42.

The needle valve 10 is held by a needle valve holding portion 46 of the nozzle body 40, and the distal end side of the needle valve 10 extends in the second fuel storage chamber 42 along the extending direction of the second fuel storage chamber 42. It is possible to advance and retreat.
The needle valve 10 includes a substantially cylindrical needle valve main body 11 that is slidably held by the needle valve holding portion 46, a movement restricting portion 12 that is formed in a bowl shape on the proximal end side of the needle valve main body 11, Is provided.

The proximal end side of the needle valve main body 11 with respect to the needle valve holding portion 46 is exposed in the needle valve closing chamber 43.
The movement restricting portion 12 is formed in a portion of the needle valve main body 11 exposed in the needle valve closing chamber 43.

  The outer diameter of the movement restricting portion 12 of the needle valve 10 is larger than the inner diameter of the portion closer to the proximal end than the stepped portion 431 of the needle valve closing chamber 43. Therefore, when the needle valve 10 is retracted, the movement restricting portion 12 hits the stepped portion 431, and the retreat of the needle valve 10 is restricted.

A step portion 13 as a needle valve opening means is formed in a ring shape along the circumferential direction in a portion of the outer peripheral surface of the needle valve main body 11 located in the vicinity of the fuel reservoir portion 421.
The outer diameter of the portion on the distal end side of the step portion 13 of the needle valve body 11 is smaller than the outer diameter of the portion on the proximal end side of the step portion 13 of the needle valve body 11. A gap through which fuel flows is formed between the outer peripheral surface of the tip side of the step portion 13 and the inner peripheral surface of the second fuel storage chamber 42.

  In the needle valve 10 described above, the distal end surface of the needle valve main body 11 is separated from the distal end side of the second fuel storage chamber 42, so that the fuel reservoir portion 421 of the second fuel storage chamber 42 and the injection hole 45 communicate with each other. When the tip end surface of the needle valve main body 11 is seated on the tip end side of the second fuel storage chamber 42, the fuel reservoir portion 421 and the injection hole 45 of the second fuel storage chamber 42 are shut off.

The injection control valve 20 is held by the injection control valve holding portion 44 of the nozzle body 40 and can advance and retreat in the first fuel storage chamber 41 along the extending direction of the first fuel storage chamber 41.
The actuator 60 is provided on the base end side of the injection control valve holding portion 44 of the injection control valve 20 and can load the injection control valve 20 in the forward direction.

FIG. 2 is an enlarged cross-sectional view of the injection control valve 20.
The injection control valve 20, the injection control valve holding part 44 is slidable and a first substantially cylindrical guide portion 22 having an outer diameter D ₁ of the as outer diameter, the tip of the guide portion 22 A substantially disc-shaped bowl-shaped enlarged portion 23 having an outer diameter D2 as a _second outer diameter provided on the side, and a third outer diameter provided on the distal end side of the enlarged portion 23 comprising a substantially cylindrical closure 24 having an outer diameter D ₃ of the dimensions, the.

Here, the outer diameter D ₂ of the enlarged diameter portion _23, the outer diameter D ₁ of the guide portion 22 _is smaller in the order of the outer diameter D ₃ of the closure.
The guide part 22 is slidably held by the injection control valve holding part 44. A reduced diameter portion 221 having a circular cross section having an outer diameter D ₁ ′ extending from the position adjacent to the enlarged diameter portion 23 toward the proximal end side is formed on the outer peripheral surface of the guide portion 22. A first fuel passage 51 is opened at a position facing the reduced diameter portion 221 in the injection control valve holding portion 44.
The enlarged diameter portion 23 and the closing portion 24 are exposed in the first fuel storage chamber 41. The base end surface of the enlarged diameter portion 23 is inclined with respect to a plane that intersects the central axis of the injection control valve 20.

  The spring 21 is provided between the distal end surface of the first fuel storage chamber 41 and the enlarged diameter portion 23 of the injection control valve 20, contacts the distal end side of the enlarged diameter portion 23, and retracts the injection control valve 20. Energize in the direction.

The above-described injection control valve 20 moves forward against the urging force of the spring 21, and the state in which the front end surface of the closing portion 24 abuts on the front end surface of the first fuel storage chamber 41 is the first of the injection control valve 20. Position.
When the injection control valve 20 is located at the first position, the front end surface of the closing portion 24 abuts on the front end surface of the first fuel storage chamber 41, and the enlarged diameter portion 23 and the step portion 411 of the first fuel storage chamber 41 are in contact with each other. A gap is formed between them.

  Since the first fuel passage 51 communicates with the distal end side of the through hole that is the injection control valve holding portion 44, and the third fuel passage 53 communicates with the distal end surface of the first fuel storage chamber 41, in this state The first fuel storage chamber 41 and the third fuel passage 53 are blocked, and the first fuel passage 51 and the first fuel storage chamber 41 are communicated with each other.

Here, the force acting in the advancing / retreating direction of the injection control device 20 by the fuel in the first fuel storage chamber 41 in a state where the injection control valve 20 is located at the first position is obtained.
A plane perpendicular to the advancing / retreating direction of the injection control device 20 is defined as a reference surface, and a surface receiving pressure in the advancing / retreating direction from the fuel in the first fuel storage chamber 41 is defined as a pressure receiving surface.

When the pressure receiving surface is inclined with respect to the reference surface, the pressure in the first fuel storage chamber 41 acts perpendicularly to the inclined pressure receiving surface, so that the pressure in the first fuel storage chamber 41 acting on the pressure receiving surface is increased. The forward / backward direction component of the pressure becomes smaller. On the other hand, the area of the pressure receiving surface is larger than the projected area of the pressure receiving surface with respect to the reference surface because the pressure receiving surface is inclined with respect to the reference surface.
As described above, even if the forward / backward direction component of the pressure in the first fuel storage chamber 41 acting on the pressure receiving surface decreases, the area of the pressure receiving surface increases according to the ratio, so that eventually the injection control device 20 The force acting in the forward / backward direction is represented by the product of the projected area of the pressure receiving surface with respect to the reference plane and the pressure in the first fuel storage chamber 41. Hereinafter, the force acting in the forward / backward direction of the injection control device 20 is obtained using this method.

The surface of the reduced diameter portion 221 of the guide portion 22 and a pressure receiving surface 22A, when the projected area with respect to the reference surface of the pressure-receiving surface 22A as _{S 1,} the projected area _{S 1} of the pressure receiving surface 22A, the following equation (1) It is represented by
_{S 1 = (D 1/2} ) 2 × π- (D 1 '/ 2) 2 × π ... (1)

Therefore, when the pressure in the first fuel storage chamber 41 is P, the force F ₁ acting in the backward direction on the pressure receiving surface 22A of the guide portion 22 is expressed by the following equation (2).
F ₁ = P × S ₁ (2)

Further, a base end surface of the enlarged diameter portion 23 and a pressure receiving surface 23A, when the projected area with respect to the reference surface of the pressure receiving surface 23A and S _2, the projected area S ₂ of the pressure receiving surface 23A, the following equation (3 ).
_{S 2 = (D 2/2} ) 2 × π- (D 1 '/ 2) 2 × π ... (3)
Thus, the force F ₂ acting in the forward direction to the pressure receiving surface 23A of the enlarged diameter portion 23 is expressed by the following equation (4).
F ₂ = P × S ₂ (4)

Further, the tip-side surface of the enlarged diameter portion 23 and a pressure receiving surface 23B, when the projected area with respect to the reference surface of the pressure receiving surface 23B and S _3, the projected area S ₃ of the pressure receiving surface 23B has the following formula (5) It is represented by
_{S 3 = (D 2/2} ) 2 × π- (D 3/2) 2 × π ... (5)

Therefore, the force F ₃ acting in the backward direction on the pressure receiving surface 23B of the enlarged diameter portion 23 is expressed by the following formula (6).
F ₃ = P × S ₃ (6)

Since the front end surface of the closing part 24 is in contact with the front end surface of the first fuel storage chamber 41, the pressure in the first fuel storage chamber 41 is not received. Accordingly, the force F applied to the injection control valve 20 by the fuel pressure in the first fuel storage chamber 41 is expressed by the following equation (7), assuming that the forward direction is positive.
F ₌ F 2 _-F 1 _{-F 3
= P × ((D 3/} 2) 2 × π- (D 1/2) 2 × π) ... (7)
Here, the outer diameter D ₃ is smaller than the outer diameter D _1, the sign of F is negative. That is, in the state where the injection control valve 20 is located at the first position, the force F in the backward direction acts on the injection control valve 20.

The state in which the injection control valve 20 is retracted and the enlarged diameter portion 23 is in contact with the step portion 411 of the first fuel storage chamber 41 is defined as a second position of the injection control valve 20.
In a state where the injection control valve 20 is located at the first position, the driving of the actuator 60 is stopped and the pressing force on the injection control valve 20 is released. The injection control valve 20 starts to move from the first position toward the second position by the backward force F due to the fuel pressure in the first fuel storage chamber 41 and the biasing force of the spring 21, The tip surface is slightly separated from the tip surface of the first fuel storage chamber 41. Then, since a force in the backward direction due to the fuel pressure in the fuel storage chamber 41 is also applied to the front end surface of the closing portion 24, the force applied to the injection control valve 20 is overwhelmingly large.

Thereafter, when the injection control valve 20 is retracted to the second position, the front end surface of the closing portion 24 and the front end surface of the first fuel storage chamber 41 are separated to form a gap, and the enlarged diameter portion 23 is the first fuel. It abuts on the step portion 411 of the storage chamber 41. In this state, the first fuel passage 51 and the first fuel storage chamber 41 are blocked, and the first fuel storage chamber 41 and the third fuel passage 53 are communicated.
FIG. 1 shows a state where the injection control valve 20 is located at the second position.

  The closing assist piston 30 is provided so as to be able to advance and retreat in the needle valve closing chamber 43, and has a substantially cylindrical partition portion 33 that slides on the inner wall surface of the needle valve closing chamber 43, and the needle valve 10 side of the partition portion 33. And an auxiliary force transmission portion 32 extending in a rod shape from the end portion.

  The needle valve closing chamber 43 is partitioned by the partition 33 into a closing auxiliary pressure chamber 432 that communicates with the third fuel passage 53 and a return pressure chamber 433 that communicates with the fourth fuel passage 54.

A portion on the base end side of the partition portion 33 has a substantially conical shape protruding toward the third fuel passage 53 side.
In addition, the partition portion 33 is formed with a minute communication path 331 that allows the closing auxiliary pressure chamber 432 and the return pressure chamber 433 to communicate with each other. The minute communication path 331 is formed between the closing assist piston 30 and the needle valve closing chamber 43 by denting the outer peripheral surface of the partition portion 33 of the closing assist piston 30.

  The spring 31 is provided between the closing assist piston 30 in the needle valve closing chamber 43 and the proximal end side of the needle valve 10, and biases the closing assist piston 30 and the needle valve 10 in a separating direction.

The above closing auxiliary piston 30 operates as follows.
That is, first, the injection control valve 20 is located at the first position, the first fuel storage chamber 41 and the third fuel passage 53 are shut off, and the position where the closing auxiliary piston 30 is most retracted by the spring 31. It is assumed that the conical portion of the partition portion 33 closes the third fuel passage 53 on the base end surface of the needle valve closing chamber 43. This state is the last retracted position of the closing assist piston 30.

In the state in which the closing auxiliary piston 30 is located at the last retracted position, the conical portion of the partition portion 33 closes the third fuel passage 53 and blocks communication between the third fuel passage 53 and the closing auxiliary pressure chamber 432. .
Further, in the state where the closing assist piston 30 is located at the last retracted position, even if the needle valve 10 is retracted until it is regulated by the movement restricting portion 12, the tip surface of the assist force transmitting portion 32 of the closing assist piston 30 and the needle The movement strokes and lengths of the closing assist piston 30 and the needle valve 10 are set so that a gap is formed between the base end surface of the valve 10 and the valve 10.

Next, when the injection control valve 20 moves backward from the first position, the first fuel storage chamber 41 and the third fuel passage 53 communicate with each other, and the fuel in the first fuel storage chamber 41 flows into the third fuel passage 53.
The second fuel passage 52 and the third fuel passage 53 communicate with each other, and the fuel in the second fuel passage 52 flows into the third fuel passage 53.
Then, due to the fuel pressure in the third fuel passage 53, the closing assist piston 30 moves forward against the biasing force of the spring 31, and the distal end surface of the assist force transmitting portion 32 comes into contact with the proximal end surface of the needle valve 10.

In this state, the fuel in the third fuel passage 53 flows into the closing auxiliary pressure chamber 432 of the needle valve closing chamber 43, and the fuel pressure in the fuel reservoir portion 421 of the second fuel storage chamber 42 and the needle valve closing chamber. The fuel pressure in the 43 closed auxiliary pressure chambers 432 is equal.
Then, the conical portion of the partition portion 33 of the closing assist piston 30 receives the fuel pressure from the closing assist pressure chamber 432 as a pressure receiving portion, so that the needle valve 10 moves forward through the closing assist piston 30. Power is added to.
At the same time, the annular step portion 13 of the needle valve 10 receives the fuel pressure from the fuel reservoir portion 421 as a pressure receiving portion, so that a force is applied to the needle valve 10 in the backward direction.

  Here, the maximum diameter of the partition portion 33 of the closing assist piston 30 is larger than the maximum diameter of the step portion 13 of the needle valve 10, and the pressure receiving area of the partition portion 33 of the close assist piston 30 is the step portion 13 of the needle valve 10. It is larger than the pressure receiving area. Therefore, the force for moving the closing assist piston 30 forward becomes larger than the force for moving the needle valve 10 backward, and the proximal end side of the needle valve 10 is pressed by the distal end surface of the assist force transmitting portion 32 of the closing assist piston 30. The needle valve 10 is advanced.

Hereinafter, the operation of the fuel injection device 1 will be described with reference to FIGS.
ST1 is in an initial state as shown in FIG. That is, fuel is supplied from the fuel supply source to the first fuel passage 51 at a high pressure, and the injection control valve 20 is moved backward by the urging force of the spring 21 to be in the second position. As a result, the enlarged diameter portion 23 of the injection control valve 20 abuts on the step portion 411 of the first fuel storage chamber 41, so that the high-pressure fuel in the first fuel passage 51 is separated from the reduced diameter portion 221 of the injection control valve 20. It remains in the gap with the inner peripheral surface of the injection control valve holding portion 44.

  Further, the urging force of the spring 31 causes the needle valve 10 to move forward and be seated on the front end side of the second fuel storage chamber 42, and the closing assist piston 30 moves backward and is located at the last retracted position so as to pass through the third fuel passage 53. It is closed. As a result, the fuel that has flowed in by the previous injection operation is confined in the second fuel storage chamber 42, the second fuel passage 52, the first fuel storage chamber 41, and the third fuel passage 53 at a certain pressure.

  In ST2, from this state, as shown in FIG. 3B, when the actuator 60 is driven, the injection control valve 20 moves forward and is positioned at the first position while resisting the biasing force of the spring 21.

Then, the front end surface of the closing portion 24 comes into contact with the front end surface of the first fuel storage chamber 41 and the first fuel storage chamber 41 and the third fuel passage 53 are shut off, so that the high pressure to the third fuel passage 53 is increased. Fuel supply is cut off.
Further, since the enlarged diameter portion 23 is separated from the step portion 411 of the first fuel storage chamber 41 and a gap is formed between the enlarged diameter portion 23 and the step portion 411 of the first fuel storage chamber 41, the first fuel The high-pressure fuel in the passage 51 passes through the gap between the reduced diameter portion 221 of the injection control valve 20 and the inner peripheral surface of the injection control valve holding portion 44, the first fuel storage chamber 41, and the second fuel passage 52, The fuel flows into the fuel reservoir 421 of the second fuel storage chamber 42. As described above, since the fuel in the fuel reservoir portion 421 is already at a certain pressure, the fuel pressure in the second fuel storage chamber 42 is increased by supplying high-pressure fuel in the first fuel passage 51. To rise.

  In ST3, when the fuel pressure in the fuel reservoir 421 reaches a predetermined pressure, the movement restricting portion 12 of the needle valve 10 is stepped by the fuel pressure in the fuel reservoir 421 as shown in FIG. The needle valve 10 moves backward against the spring 31 until it hits the portion 431. Thereby, the needle valve 10 is separated from the front end side of the second fuel storage chamber 42, and the fuel in the second fuel storage chamber 42 is injected through the injection hole 45.

In ST4, the driving of the actuator 60 is stopped and the pressing force on the injection control valve 20 is released. Then, as shown in FIG. 4 (a), in addition to the urging force of the spring 21, the injection control valve 20 moves backward to the second position due to the backward force generated by the fuel pressure in the first fuel storage chamber 41. To position. The enlarged diameter portion 23 comes into contact with the step portion 411 of the first fuel storage chamber 41 and closes the injection control valve holding portion 44. As a result, the first fuel passage 51 and the first fuel storage chamber 41 are blocked, and the first fuel storage chamber 41 and the third fuel passage 53 communicate with each other. Therefore, the fuel in the first fuel storage chamber 41 flows into the third fuel passage 53 through the gap between the front end surface of the closing portion 24 and the front end surface of the first fuel storage chamber 41, and enters the third fuel passage 53. The pressure increases.
Since the closing auxiliary piston 30 is located at the last retracted position, the third fuel passage 53 is closed by the partition portion 33, but this partition portion 33 is caused by the fuel pressure flowing into the third fuel passage 53. The portion exposed to the third fuel passage 53 among the conical portions is pressed, and the closing auxiliary piston 30 moves forward.

  In ST5, as shown in FIG. 4B, since the closing assist piston 30 has advanced, the block of the third fuel passage 53 by the partition 33 is released, and the fuel flowing into the third fuel passage 53 is closed by the needle valve. It flows into the closing auxiliary pressure chamber 432 of the chamber 43 and the pressure in the closing auxiliary pressure chamber 432 rises. When the pressure inside the closed auxiliary pressure chamber 432 reaches a predetermined pressure, the entire conical portion of the partition 33 is pressed by the fuel pressure flowing into the closed auxiliary pressure chamber 432, and the closed auxiliary piston 30 moves forward. Then, the distal end surface of the auxiliary force transmitting portion 32 of the closing assist piston 30 comes into contact with the proximal end surface of the needle valve 10.

  In ST6, as shown in FIG. 4C, the fuel in the closing auxiliary pressure chamber 432 presses the partition portion 33. Here, the force applied in the direction in which the closing assist piston 30 moves forward is more than the force applied in the direction in which the fuel in the fuel reservoir portion 421 of the second fuel storage chamber 42 presses the step portion 13 and moves backward to the needle valve 10. Is also big. Accordingly, the closing assist piston 30 moves forward together with the needle valve 10, the needle valve 10 is seated on the distal end side of the second fuel storage chamber 42, and fuel injection from the injection hole 45 is stopped.

In ST7, as shown in FIG. 5, the fuel inside the auxiliary closing pressure chamber 432 gradually flows out into the return pressure chamber 433 through the minute communication path 331 formed in the partition 33, and this return pressure chamber The fuel flowing out to 433 is discharged to the outside of the nozzle body 40 through the fourth fuel passage 54.
As a result, the pressure inside the closing auxiliary pressure chamber 432 gradually decreases, and when the pressure inside the closing auxiliary pressure chamber 432 becomes less than a predetermined pressure, the closing auxiliary piston 30 moves backward by the biasing force of the spring 31. To the last retreat position. As a result, the fuel is trapped in the second fuel storage chamber 42, the second fuel passage 52, the first fuel storage chamber 41, and the third fuel passage 53 with a certain level of pressure, and returns to the initial state.

According to this embodiment, there are the following effects.
(1) The outer diameter D ₁ of the guide part 22 is made larger than the outer diameter D ₃ of the closing part 24. Therefore, the sum (F) of the force that the injection control valve 20 receives in the backward direction (that is, the second position direction) from the fuel pressure P in the first fuel storage chamber 41 in a state where the injection control valve 20 is located at the first position. ₁ + F ₃ ) is larger than the total force F ₂ received in the forward direction (that is, the first position direction). Therefore, as a result, a reverse force F acts on the injection control valve 20.
That is, in the state where the injection control valve 20 is located at the first position, a force toward the second position acts on the injection control valve 20, so that it is easy to shift from the first position to the second position. 20 can be operated quickly.

(2) Since the spring 21 for biasing the injection control valve 20 in the backward direction is provided, the injection control valve is moved toward the second position by the spring 21 in a state where the injection control valve 20 is located at the first position. Since it is biased, it is possible to move from the first position to the second position more quickly.
Further, if the reverse speed of the injection control valve 20 is maintained at the same level as before, a reverse force acts on the injection control valve 20 by both the spring 21 and the fuel pressure in the first fuel storage chamber 41. The urging force of the spring 21 can be reduced compared to the conventional case. That is, the spring 21 can be reduced in size.

  (3) When the injection control valve 20 shifts from the first position to the second position, the fuel in the first fuel storage chamber 41 flows into the third fuel passage 53, but the closing assist piston 30 and the needle valve closing chamber 43. Accordingly, the fuel in the first fuel storage chamber 41 is prevented from flowing out of the fuel injection device 1 through the third fuel passage 53, the needle valve closing chamber 43, and the fourth fuel passage 54, and the fuel. Since the outflow amount to the outside of the fuel injection device 1 can be reduced, the efficiency of the entire fuel supply system can be improved.

(4) The closing assist piston 30 transmits the pressing force by the fuel pressure in the needle valve closing chamber 43 to the needle valve 10 in the forward direction, and the needle valve 10 is advanced to stop the fuel injection. . Therefore, the closing speed of the needle valve 10 can be improved, and the falling characteristic of the fuel injection pressure can be improved.
(5) In the state in which the fuel pressure in the second fuel storage chamber 42 and the fuel pressure in the needle valve closing chamber 43 are equal, a force for advancing the needle valve 10 by the fuel pressure acting on the closing assist piston 30 The force that causes the needle valve 10 to retreat due to the fuel pressure acting on the nozzle 13 is made larger. Therefore, when stopping the fuel injection, the fuel pressure acts in the direction of moving the needle valve 10 forward, so that the fuel injection can be stopped quickly. Therefore, the response time from when the injection control valve 20 is retracted until the fuel injection stops can be shortened. As a result, since the minimum injection time can be further shortened and the minimum injection amount can be reduced, various injection methods can be realized.

It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.
For example, in this embodiment, the injection control valve 20 is driven by the piezo-type actuator 60. However, the present invention is not limited to this, and it may be driven by an electromagnetic or hydraulic actuator.
In the present embodiment, the minute communication path 331 is formed by denting the outer peripheral surface of the partition portion 33 of the closing assist piston 30, but the present invention is not limited to this. It may be provided, or may be formed on the inner peripheral surface of the needle valve closing chamber 43 of the nozzle body 40.

In the present embodiment, the proximal end side of the needle valve 10 is directly pressed by the auxiliary force transmission unit 32 of the closing auxiliary piston 30, but the present invention is not limited to this, and the gap between the closing auxiliary piston 30 and the needle valve 10 is not limited. A member may be provided, and the proximal end side of the needle valve 10 may be pressed through this member.
Moreover, in this embodiment, although the level | step-difference part 13 was formed in one place of the outer peripheral surface of the needle valve main body 11, not only this but a step part is provided in several places, such as the front end side outer peripheral surface of the needle valve main body 11. Also good.
In the present embodiment, the spring 21 is disposed on the distal end side of the injection control valve holding portion 44 of the injection control valve 20, but is not limited thereto, and is disposed on the proximal end side of the injection control valve holding portion 20. It is sufficient that the injection control valve 20 can be urged in the backward direction.

It is sectional drawing which shows the structure of the fuel-injection apparatus which concerns on one Embodiment of this invention. It is an expanded sectional view of the injection control valve of the fuel injection device concerning the embodiment. FIG. 6 is a diagram (No. 1) for explaining the operation of the fuel injection device according to the embodiment; FIG. 6 is a diagram (No. 2) for explaining the operation of the fuel injection device according to the embodiment; FIG. 6 is a view (No. 3) for explaining the operation of the fuel injection device according to the embodiment. It is sectional drawing which shows the structure of the fuel-injection apparatus which concerns on the prior art example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection apparatus 10 Needle valve 13 Level difference part (needle valve opening means)
20 Injection control valve 21 Spring (elastic member)
22 Guide part 23 Expanded diameter part 24 Closure part 30 Closure assist piston (outflow suppression means, needle valve closure means)
40 Nozzle body 41 First fuel storage chamber 42 Second fuel storage chamber (needle valve opening means)
43 Needle valve closing chamber (outflow suppression means, third fuel storage chamber, needle valve closing means)
44 Injection control valve holding portion 45 Injection hole 46 Needle valve holding portion 51 First fuel passage 52 Second fuel passage 53 Third fuel passage 54 Fourth fuel passage 60 Actuator 421 Fuel reservoir (needle valve opening means)
432 Closed auxiliary pressure chamber 433 Return pressure chamber D ₁ 1st outer diameter D ₂ 2nd outer diameter D ₃ 3rd outer diameter

Claims (6)

A first fuel storage chamber, a second fuel storage chamber, a third fuel storage chamber, and a nozzle body in which nozzle holes extending from the second fuel storage chamber to the outside of the fuel injection device are formed;
A needle valve held in a needle valve holding portion inside the nozzle body;
Needle valve opening means provided on the tip side of the needle valve holding portion inside the nozzle body and having the second fuel storage chamber;
Needle valve closing means provided on the base end side of the needle valve holding portion inside the nozzle body and having the third fuel storage chamber;
An injection control valve held in an injection control valve holding portion inside the nozzle body and capable of moving forward and backward in the first fuel storage chamber,
The nozzle body includes a first fuel passage from a fuel supply source to the first fuel storage chamber, a second fuel passage from the first fuel storage chamber to the second fuel storage chamber, and from the first fuel storage chamber. A third fuel passage extending to the third fuel storage chamber and a fourth fuel passage extending from the third fuel storage chamber to a low pressure portion outside the fuel injection device are formed;
The injection control valve is slidable in the injection control valve holding portion and has a first outer diameter dimension and a substantially cylindrical guide portion;
A substantially disk-shaped bowl-shaped enlarged portion provided on the distal end side of the guide portion and having a second outer diameter;
A substantially cylindrical closing portion provided on the distal end side of the enlarged diameter portion and having a third outer diameter,
The injection control valve moves forward to the first position, blocks the passage leading to the third fuel passage of the first fuel storage chamber on the distal end side of the closing portion, and moves backward to the second position to Blocking the passage leading to the first fuel passage of the first fuel storage chamber on the proximal end side of the enlarged diameter portion;
The needle valve moves forward and is seated on the nozzle body, thereby shutting off the second fuel storage chamber and the nozzle hole, and retreating and moving away from the nozzle body, thereby the second fuel storage chamber. Communicating the chamber with the nozzle hole,
The needle valve opening means retracts the needle valve by the fuel pressure in the second fuel storage chamber,
The needle valve closing means advances the needle valve by the fuel pressure in the third fuel storage chamber,
The fuel injection device, wherein the second outer diameter dimension of the enlarged diameter portion, the first outer diameter dimension of the guide portion, and the third outer diameter dimension of the closing portion become smaller in this order. The fuel injection device according to claim 1,
An actuator that is provided on the base end side of the injection control valve holding portion of the injection control valve and can load the injection control valve in a forward direction;
And an elastic member that biases the injection control valve in the backward direction. The fuel injection device according to claim 1 or 2,
When the injection control valve shifts from the first position to the second position, the fuel in the first fuel storage chamber passes through the third fuel passage, the third fuel storage chamber, and the fourth fuel passage. A fuel injection device comprising an outflow suppression means for suppressing the flow through the fuel injection device. The fuel injection device according to claim 3, wherein
The needle valve closing means includes a closing auxiliary piston provided to be able to advance and retreat in the third fuel storage chamber,
The closing assist piston shuts off the third fuel passage and the third fuel storage chamber at the last retracted position, and makes the third fuel passage and the third fuel storage chamber communicate with each other by shifting to the forward movement state. ,
In the advanced state of the closing auxiliary piston, the third fuel storage chamber includes a closing auxiliary pressure chamber that communicates with the third fuel passage and a return pressure chamber that communicates with the fourth fuel passage. Partitioned,
The closing assist piston is capable of transmitting a pressing force due to fuel pressure in the closing assist pressure chamber to the needle valve in a forward direction,
The closing auxiliary piston shifts from the advanced state to the last retracted position, and shuts off the third fuel passage and the closing auxiliary pressure chamber, so that the fuel in the first fuel storage chamber becomes the third fuel. A flow suppression means for suppressing the flow of fuel in the first fuel storage chamber from flowing out of the fuel injection device by suppressing the flow into the third fuel storage chamber through the passage. A fuel injection device. The fuel injection device according to claim 4, wherein
The injection control valve is retracted from the first position so that the second fuel passage and the third fuel passage communicate with each other, and the fuel pressure in the second fuel storage chamber, the fuel pressure in the third fuel storage chamber, A fuel injection device characterized in that the force for advancing the needle valve by the needle valve closing means is greater than the force for retreating the needle valve by the needle valve opening means in a state where A nozzle body in which a first fuel storage chamber is formed;
An injection control valve held in an injection control valve holding portion inside the nozzle body and capable of moving forward and backward in the first fuel storage chamber,
The nozzle body includes a first fuel passage from a fuel supply source to the first fuel storage chamber, an injection fuel passage from the first fuel storage chamber to the injection hole, and a fuel injection device from the first fuel storage chamber. A return fuel passage, which leads to the low pressure part outside, is formed,
The injection control valve is slidable in the injection control valve holding portion and has a first outer diameter dimension and a substantially cylindrical guide portion;
A substantially disk-shaped bowl-shaped enlarged portion provided on the distal end side of the guide portion and having a second outer diameter;
A substantially cylindrical closing portion provided on the distal end side of the enlarged diameter portion and having a third outer diameter,
The injection control valve moves forward to the first position, shuts off the communication portion leading to the return fuel passage of the first fuel storage chamber on the tip side of the second closing portion, and moves backward to the second position. Shutting off the communication portion reaching the first fuel passage of the first fuel storage chamber on the base end side of the first closing portion;
The fuel injection device, wherein the second outer diameter dimension of the enlarged diameter portion, the first outer diameter dimension of the guide portion, and the third outer diameter dimension of the closing portion become smaller in this order.

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