JP6376988B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve for an internal combustion engine.

[Conventional technology]
Conventionally, as an example of a fuel injection valve that injects fuel into a cylinder of an internal combustion engine (engine), the control valve is switched using an actuator displacement to adjust the fuel pressure (control chamber pressure) in the control chamber. A fuel injection valve (hereinafter, a conventional injector) that controls the opening and closing operation of the needle has been proposed (see, for example, Patent Document 1).
This conventional injector includes a needle that opens and closes a nozzle hole, a control chamber that stores fuel pressure acting on the needle in a valve closing direction, a control valve that controls increase and decrease of the fuel pressure in the control chamber, and this control And an actuator that generates a driving force for switching the valve body (hereinafter referred to as a control valve) of the valve.

This conventional injector employs a configuration in which a control valve is switched using a piezoelectric actuator mainly composed of a piezoelectric element stack as an actuator.
Further, as the control valve, a control valve that selectively communicates a communication port that is in constant communication with the control chamber via a common flow path to a low pressure port that communicates with the low pressure fuel passage and a high pressure port that communicates with the high pressure fuel passage, A control valve having a three-way valve structure having a valve spring that urges the control valve to open the high-pressure port and close the low-pressure port is used. The wall surface of the control valve chamber is provided with a low-pressure seat that is the peripheral edge of the low-pressure port and a high-pressure sheet that is the peripheral edge of the high-pressure port. The control valve is housed in the control valve chamber together with the valve spring.

  In this case, when the actuator is energized (ON) based on the injector valve opening command from the electronic control unit (ECU), the actuator is extended and displaced, the control valve is pushed down, and the low pressure seal state is switched to the high pressure seal state. As a result, the control valve is seated on the high-pressure seat and the communication between the high-pressure port and the communication port is blocked, so that the high-pressure fuel does not flow into the control chamber from the high-pressure fuel passage through the control valve chamber. Further, since the control valve is detached from the low pressure seat and the low pressure port and the communication port communicate with each other, the fuel flows out from the control chamber to the low pressure fuel passage through the control valve chamber. As a result, the fuel pressure in the control chamber is quickly reduced, and the valve opening response of the needle is improved.

  On the other hand, when energization to the actuator is stopped (OFF) based on an injector valve closing command from the ECU, the actuator is contracted and displaced, and the control valve is switched from the high pressure seal state to the low pressure seal state by the urging force of the valve spring. As a result, the control valve is seated on the low-pressure seat and the communication between the low-pressure port and the communication port is blocked, so that fuel does not flow out from the control chamber to the low-pressure fuel passage via the control valve chamber. Further, since the control valve is detached from the high-pressure seat and the high-pressure port and the communication port communicate with each other, the high-pressure fuel flows from the high-pressure fuel passage into the control chamber through the control valve chamber. As a result, the fuel pressure in the control chamber rises quickly, and the valve closing response of the needle is improved.

By the way, in the conventional injector, for the purpose of independently controlling the opening / closing valve speed of the needle, the orifice is not set in the common flow path, and the in-orifice is set in the high-pressure fuel passage upstream of the control valve chamber. In addition, an out-orifice is set in the low-pressure fuel passage on the downstream side of the control valve chamber.
In this case, the needle opening speed can be set by the out-orifice flow rate (throttle diameter), and the needle closing speed can be set by the in-orifice flow rate (throttle diameter), so the needle opening and closing valve speed must be set independently. Can do. As a result, the degree of freedom in designing the needle opening / closing valve speed is improved.

[Conventional technical problems]
However, in the conventional injector, when the out-orifice flow rate is increased, the needle valve opening speed is improved, and the fuel injection rate is improved, the needle valve closing speed is also improved in order to improve the controllability of the fuel injection amount. However, the in-orifice flow rate, which regulates the flow rate of high-pressure fuel introduced from the high-pressure fuel passage through the control valve chamber to the control chamber, restricts the driving force of the actuator against the high-pressure seat load of the control valve. Therefore, there is a limit in improving the needle valve closing speed.
As a result, if the out-orifice flow rate is increased and conversely the in-orifice flow rate is decreased, it takes time for the fuel pressure in the control chamber to rise to the needle valve closing pressure after the energization of the actuator is stopped.
Therefore, since the needle valve closing timing (timing) is delayed, the injection end delay with respect to the injector valve closing command from the ECU increases, and there is a problem that the accuracy and controllability of the injection amount deteriorate. In particular, in the case of an injector that switches and drives the control valve using the extension displacement of the piezo actuator, the above problem becomes more prominent.

The conventional injector is configured such that high-pressure fuel for closing the needle flows into the control chamber from the in-orifice of the high-pressure fuel passage through the high-pressure seat of the control valve. As a result, the in-orifice flow rate = needle closing speed is restricted by the high-pressure seat diameter of the control valve and the valve lift amount when the low-pressure seal is in effect.
Here, if the fuel injection pressure, that is, the fuel pressure flowing through the high pressure fuel passage is increased for the purpose of improving the engine output and exhaust emission, the high pressure seat load of the control valve when the needle is opened is increased. Will increase. As a result, in order to increase the valve lift amount when the control valve is in the high-pressure seat diameter and the low-pressure seal state and to improve the needle valve closing speed, it is required to improve the driving force of the actuator.
Therefore, when the out-orifice flow rate is increased, the fuel injection rate is improved, or the fuel injection pressure is increased, the needle opening speed and the needle closing speed are not increased without increasing the driving force of the actuator. It was difficult to improve the valve speed.

JP 2006-046323 A

  An object of the present invention is to provide a fuel injection valve capable of improving the needle valve opening speed and the needle valve closing speed without increasing the driving force of an actuator.

According to the invention described in claim 1 (fuel injection valve), when the valve body of the control valve is switched to the high-pressure seal state by the driving force of the actuator or the like, and the on-off valve is displaced to the fully closed position that closes the second path, The introduction of fuel into the control room is shut off, and the fuel flows out from the control room. As a result, fuel flows out from the control chamber to the low pressure side of the fuel system via the communication port, the control valve chamber, the low pressure port, and the low pressure fuel passage, and the fuel pressure in the control chamber decreases. When the fuel pressure in the control chamber, that is, the fuel pressure acting on the needle in the valve closing direction is reduced to the needle opening pressure, the needle is opened (lifted) and fuel injection into the cylinder of the internal combustion engine is started. The
At this time, the needle opening speed is set by the fuel flow rate (out orifice flow rate) defined by the out orifice.

  On the other hand, when the valve body of the control valve is switched to the low-pressure seal state by the driving force of the actuator and the on-off valve is displaced to the fully open position that opens the second path, fuel is introduced into the control chamber, Fuel outflow is blocked. As a result, high-pressure fuel is introduced from the high-pressure fuel passage to the control chamber via the first route (first in-orifice, high-pressure port, control valve chamber and communication port), and the second route (second The high pressure fuel is introduced into the control chamber via the in-orifice and bypassing the control valve chamber, and the fuel pressure in the control chamber increases. When the fuel pressure in the control chamber, that is, the fuel pressure acting on the needle in the valve closing direction rises to the needle valve closing pressure, the needle is closed (seat) and fuel injection into the cylinder of the internal combustion engine is completed. .

At this time, the needle valve closing speed is set by the fuel flow rate (first and second in-orifice flow rates) defined by the first and second in-orifices.
Therefore, even when the out-orifice flow rate is increased, the fuel injection rate is improved, or the fuel injection pressure is increased, the in-orifice is divided into at least two first and second in-orifices. Since the desired needle valve closing speed can be realized with the total flow rate of at least two first and second in-orifices, the high-pressure seat load on the valve body of the control valve can be reduced. As a result, the needle valve opening speed and the needle valve closing speed can be improved without increasing the driving force of the actuator. Thereby, the on-off valve responsiveness of the needle can be improved.

FIG. 1 is a cross-sectional view showing a piezo injector (Example 1). (Example 1) which is sectional drawing which showed the low-pressure seal | sticker state by a control valve. It is sectional drawing which showed the high pressure seal state by a control valve (Example 1). (Example 2) which is sectional drawing which showed the low-pressure seal | sticker state by a control valve. It is sectional drawing which showed the high pressure seal state by a control valve (Example 2). (Example 3) which is sectional drawing which showed the low pressure seal state by a control valve. (Example 3) which is sectional drawing which showed the high pressure seal state by a control valve. (A) is sectional drawing which showed the low pressure seal state by a control valve, (b) is sectional drawing which showed the high pressure seal state by a control valve (Example 4). (A) is sectional drawing which showed the low pressure sealing state by a control valve, (b) is sectional drawing which showed the high pressure sealing state by a control valve (Example 5). (Example 6) which is sectional drawing which showed the main structures of the piezo injector. (A) is sectional drawing which showed the low pressure seal state by a control valve, (b) is sectional drawing which showed the high pressure seal state by a control valve (Example 6). (A) is sectional drawing which showed the perpendicular | vertical cross-sectional shape orthogonal to the axial direction of a low pressure flow path hole and a displacement transmission pin, (b) is sectional drawing which showed the high pressure seal state by a control valve (Example) 6 and 7). (A) is sectional drawing which showed the low pressure seal state by a control valve, (b) is sectional drawing which showed the high pressure seal state by a control valve (Example 7). (A) is sectional drawing which showed the low pressure seal state by a control valve, (b) is sectional drawing which showed the high pressure seal state by a control valve (Example 8).

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

[Configuration of Example 1]
1 to 3 show an injector (Embodiment 1) used in a fuel injection system to which the present invention is applied.

The fuel injection valve of the internal combustion engine of the present embodiment is a direct injection type that injects fuel spray in the form of a mist 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. Piezo injector (hereinafter abbreviated as injector). This injector is used as a fuel injection valve of a common rail type fuel injection system (accumulation type fuel injection device) known as a fuel injection system for an internal combustion engine (engine).
The injector has a plurality of nozzle holes (described later) communicating with the combustion chambers of the cylinders of the engine, a bottomed cylindrical nozzle body 2 containing a needle 1 and the like for opening and closing these nozzle holes, and the needle 1. On the other hand, a control valve having a three-way two-position switching valve (hereinafter referred to as a three-way valve) structure for increasing / decreasing the fuel pressure acting in the valve closing direction, and an actuator for generating a driving force for switching the control valve using its own displacement And a cylindrical injector body 4 containing 3 or the like.

  On the central axis of the nozzle body 2 of the injector, a bag hole-like needle accommodation hole is formed which opens at the contact surface of the nozzle body 2 and extends straight from the opening side to the back side in the nozzle axis direction. Inside the needle housing hole, a needle 1 that can reciprocate in the axial direction, a needle spring 5 that urges the needle 1 in the valve closing direction, a control plate 6 that is a floating valve, and the control plate 6 Is housed in a control plate spring 7 that urges the valve 1 in the valve closing direction, and a cylindrical nozzle cylinder 8 that supports the sliding portion of the needle 1 in a reciprocating manner and supports the control plate 6 in a reciprocating manner. Has been.

A valve body 9 and an orifice plate 10 are installed between the nozzle body 2 and the injector body 4. A control valve chamber 13 for accommodating control valves (control valve 11 and valve spring 12) is formed between the valve body 9 and the orifice plate 10.
Here, the control valve is a pressure control valve that causes the fuel to flow out from the pressure control chamber 14 to the low pressure side of the fuel system through a fuel discharge passage (described later) when the control valve 11 is opened.
Details of the control valve of this embodiment will be described later.

On the wall surface (bottom surface) of the control valve chamber 13 of the valve body 9, a low-pressure seat surface having a planar ring shape (or a truncated cone (taper) cylinder shape) on which a low pressure side valve portion (described later) of the control valve 11 can be seated A low pressure side valve seat) 15 is formed. In the central portion of the low-pressure seat surface 15, a low-pressure port 16 that connects the control valve chamber 13 and a low-pressure fuel passage (described later) is opened.
In addition, a planar ring-shaped high pressure seat surface (high pressure side valve seat) 17 on the upper end surface of the orifice plate 10 facing the control valve chamber 13 and on which a high pressure side valve portion (described later) of the control valve 11 can be seated. Is formed. In the central portion of the high pressure seat surface 17, a high pressure port 18 that opens a high pressure fuel passage (described later) and the control valve chamber 13 is opened.
A communication port 19 that is always in communication with the pressure control chamber 14 is formed in the wall surface of the control valve chamber 13 of the valve body 9.
An annular valve seat surface (described later) on which the valve portion of the control plate 6 can be seated is formed on the lower end surface of the orifice plate 10 in the figure.

In the state where the valve body 9 and the orifice plate 10 are sandwiched between the contact surface of the nozzle body 2 and the contact surface of the injector body 4, the injector body 4 is screwed to the tip end side in the axial direction of the injector body 4. A retaining nut 20 is provided for fixing.
A piezo-accommodating hole that extends straight in the axial direction is formed at a position that is eccentric (offset) by a predetermined radial distance from the central axis of the injector body 4. Inside the piezo-accommodating hole, there is an actuator 3 for switching and driving the valve body (control valve 11) of the control valve, and an oil-tight chamber 23 between the piezo piston 21 and the valve piston 22, and the actuator 3 is extended and displaced. And a displacement enlarging mechanism for enlarging and transmitting it to the valve piston 22. A valve piston spring 24 is also accommodated inside the piezoelectric accommodation hole.

A base end side end (anti-injection hole side end) of the injector body 4 of the injector is connected to a high pressure generating part such as a supply pump or a common rail provided on the high pressure side of the fuel system via a high pressure pipe. And an outlet port connected to a fuel tank provided on the low pressure side of the fuel system or a low pressure portion of the fuel supply path through a low pressure pipe. Further, an external connection connector for connecting the piezoelectric lead terminal of the actuator 3 and an external circuit (external power supply or external control circuit: ECU) is provided on the side opposite to the injection hole of the injector body 4.
The injector controls the opening / closing operation of the needle 1 by adjusting (increasing / decreasing) the fuel pressure in the pressure control chamber 14 by switching and driving the control valve 11 by using the expansion / contraction displacement of the actuator 3. Thus, the fuel injection amount, the injection timing, and the injection pattern (injection rate) injected into the combustion chamber of the engine cylinder are controlled.

The needle housing hole of the nozzle body 2 is a fuel having a hole diameter larger than the guide diameter of the needle 1 on the downstream side in the fuel flow direction (fuel flow direction) from the spring housing chamber 25 that houses the needle spring 5. A reservoir chamber 26 is provided. The nozzle body 2 is provided with a plurality of injection holes 27 communicating with a concave sac chamber provided downstream of the fuel reservoir chamber 26 in the fuel flow direction.
Here, the fuel reservoir chamber 26 is provided in an intermediate portion of the needle accommodation hole. The fuel pressure introduced into the fuel reservoir chamber 26 is a valve opening direction oil pressure (FO) that acts as a biasing force that biases the needle 1 in the valve opening direction.
The plurality of injection holes 27 are provided on the downstream side in the fuel flow direction with respect to the seat portion (valve seat) on which the valve portion of the needle 1 can be seated, and communicate with the inside and outside of the needle accommodation hole. That is, the plurality of nozzle holes 27 communicate the combustion chamber of the engine cylinder with the inside of the nozzle body 2.

  The needle 1 is a valve member of a fuel injection valve, and is accommodated in the needle accommodation hole so as to be reciprocally movable. On the tip end side in the axial direction of the needle 1, a valve portion is provided that closes and opens the plurality of injection holes 27 in contact with and away from the needle seat surface of the nozzle body 2. Further, on the proximal end side in the axial direction of the needle 1, there is provided a sliding portion (small diameter portion: hereinafter referred to as piston portion) 28 that can reciprocate with respect to the hole wall surface of the guide hole (cylinder hole) of the nozzle cylinder 8. ing. On the end surface of the piston portion 28, a housing recess that houses a part of the control plate spring 7 and forms a part of the pressure control chamber 14 is provided.

An annular step is provided between the piston portion 28 of the needle 1 and the needle axial direction portion (medium diameter portion).
The needle spring 5 is a needle biasing means (elastic member) that generates a biasing force (elastic force, spring set load: Fsp) that biases the needle 1 in the valve closing direction. The needle spring 5 is disposed in a compressed state in the nozzle axial direction between an annular spring seat 29 fixed to the outer periphery of the middle diameter portion of the needle 1 and an annular end surface (spring seat portion) of the nozzle cylinder 8. It is a compression coil spring.

Here, the pressure control chamber 14 is surrounded by the upper end surface (base end side end surface) of the needle 1 in the axial direction, the bottom surface of the recess on the base end side of the needle 1, the inner peripheral surface of the nozzle cylinder 8, and the control plate 6. It is space. The fuel pressure introduced into the pressure control chamber 14 is a valve closing direction hydraulic pressure (FC) that acts on the needle 1 as a biasing force that biases the needle 1 in the valve closing direction.
The pressure control chamber 14 is a variable volume space formed between the valve-closing pressure receiving surface of the control plate 6 and the pressure receiving surface of the piston portion 28 of the needle 1. The fuel pressure introduced into the pressure control chamber 14 is a valve closing direction hydraulic pressure (FC) that acts on the control plate 6 as a biasing force that biases the control plate 6 in the valve closing direction.

Next, the high-pressure introduction passage and the fuel discharge passage of the injector will be briefly described with reference to FIGS.
The high pressure introduction flow path includes a first high pressure introduction flow path for supplying high pressure fuel introduced from the inlet port of the injector body 4 to the plurality of injection holes 27 via the fuel reservoir chamber 26, and the first high pressure introduction flow. A second high-pressure introduction passage for branching from the passage and bypassing the control valve chamber 13 to introduce high-pressure fuel into the pressure control chamber 14; And a third high-pressure introduction passage for introducing high-pressure fuel into the pressure control chamber 14.

The first high pressure introduction flow path is a high pressure flow path hole 31 to 33 communicating with the inlet port and the needle accommodation hole, a fuel flow path formed between the outer peripheral surface of the nozzle cylinder 8 and the hole wall surface of the needle accommodation hole ( Clearance) 34, a fuel flow path 35 that communicates the fuel flow path 34 and the fuel reservoir chamber 26, a fuel flow path 36 that communicates the fuel reservoir chamber 26 and the plurality of nozzle holes 27, and the like.
The fuel flow path 35 is an annular flow path formed between the outer peripheral surface of the needle 1 and the hole wall surface of the needle accommodation hole. The fuel flow path 36 is formed in the needle housing hole, and is formed between the needle seat surface of the nozzle body 2 and the valve portion of the needle 1 when the injector is opened, A sac chamber that communicates the fuel flow path and the plurality of nozzle holes 27 is included.

The second high-pressure introduction channel branches from a branch portion between the high-pressure channel holes 32 and 33, and communicates with the high-pressure channel holes 32 and 33, and the high-pressure channel hole 37 and the channel gap. A main in-orifice (hereinafter referred to as an in-orifice hole) 38 communicating with 48 is provided.
The in-orifice hole 38 is formed of a high-pressure fuel introduced into the pressure control chamber 14 from the high-pressure fuel passages (31 to 34) via the second introduction passage (described later) through a non-throttle passage (described later). This is a second inlet-side throttle hole (second in-orifice) that regulates the flow rate.

The third high-pressure introduction flow path includes a high-pressure fuel passage capable of introducing high-pressure fuel from the outside of the injector to the pressure control chamber 14 via the control valve chamber 13, a common flow path communicating with the control valve chamber 13, and the common flow path And a pressure control chamber 14 are provided, and a non-throttle flow path that does not restrict the flow rate of the flowing fuel is provided.
The high pressure fuel passage includes high pressure passage holes 31 to 33 and a fuel passage 34, a high pressure passage hole 37 communicating with the high pressure passage holes 31 to 33, an in-orifice hole 38 communicating with the high pressure passage hole 37, An annular high-pressure communication path 41 communicating with the high-pressure flow path holes 31 to 33 and the fuel flow path 34, a high-pressure flow path hole 42 communicating with the high-pressure communication path 41, and a sub-in orifice communicating with the high-pressure flow path hole 42 And a hole (hereinafter referred to as an in-orifice hole) 43.

The in-orifice hole 43 is a first inlet-side throttle hole (first in-orifice) that regulates the flow rate of high-pressure fuel introduced into the pressure control chamber 14 via the control valve chamber 13.
The control valve chamber 13 is introduced into the pressure control chamber 14 on the wall surface of the control valve chamber 13, and the low pressure port 16 communicating the control valve chamber 13 with the low pressure fuel passage through which fuel flows from the pressure control chamber 14 to the low pressure side of the fuel system. A high-pressure port 18 that communicates with the high-pressure fuel passage through which the high-pressure fuel flows and the control valve chamber 13 and a communication port 19 that always communicates with the pressure control chamber 14 through the common flow path hole 45 are formed.

The shared flow path has a shared flow path hole 45 that communicates the communication port 19 with the flow path without restriction. The common flow path hole 45 is a fuel flow path for allowing fuel to flow into and out of the pressure control chamber 14, and is always in communication with the control valve chamber 13. That is, the common flow path hole 45 is a flow path hole through which high-pressure fuel introduced from the control valve chamber 13 to the pressure control chamber 14 flows during low-pressure sealing of the control valve. The common channel hole 45 is a channel hole through which the fuel flowing out from the pressure control chamber 14 to the control valve chamber 13 flows when the control valve is sealed at high pressure.
The non-throttle flow path is an introduction flow path that introduces high-pressure fuel from the common flow path hole 45 to the pressure control chamber 14, bypassing a flow path with a throttle that will be described later, and a flow path gap 48 that communicates with the common flow path hole 45. , And a communication channel 49 that communicates the channel gap 48 with the pressure control chamber 14.
The channel gap 48 includes an annular groove formed (recessed) on the valve seat surface of the orifice plate 10.

The fuel discharge channel includes a throttled channel, a common channel hole 45, a control valve chamber 13, a low-pressure fuel channel, and an outlet port that throttle the flow rate of the fuel that passes through the high-pressure fuel introduced into the pressure control chamber 14. This is a fuel return path for flowing out to the low pressure side of the fuel system.
The throttled flow path of the fuel discharge flow path has a flow path hole 51 communicating with the pressure control chamber 14, a main out orifice hole (hereinafter referred to as an out orifice hole) 52, etc. communicating with the flow path hole 51.

The low-pressure fuel passage includes a low-pressure passage hole 54 communicating with the low-pressure port 16, a spring accommodating chamber 55 communicating with the low-pressure passage hole 54, a plurality of radial communication holes 56 communicating with the spring accommodating chamber 55, and these A low-pressure flow path 57 that communicates the radial communication hole 56 and the outlet port is provided.
The out-orifice hole 52 is installed upstream of the control valve chamber 13 in the fuel flow direction, and flows out from the pressure control chamber 14 to the low-pressure fuel passage through the common flow path hole 45 and the control valve chamber 13. It is an outlet side throttle hole that regulates the flow rate of fuel. The out orifice hole 52 is formed on the central axis of the control plate 6. The upstream end of the low-pressure port 16 opens at the bottom surface (top surface) of the concave control valve chamber 13.

The nozzle cylinder 8 has an inner peripheral wall surface that forms a communication channel 49 (such as a communication groove extending in the nozzle axis direction) that communicates the common channel hole 45 and the pressure control chamber 14 with the outer periphery of the control plate 6. Have. The inner peripheral wall surface of the nozzle cylinder 8 is provided with a guide hole for supporting the piston portion 28 of the needle 1 so as to be reciprocally slidable and supporting the control plate 6 so as to be reciprocally movable.
The nozzle cylinder 8 is connected to the joint portion of the orifice plate 10 by welding. The nozzle cylinder 8 is disposed so as to protrude from the coupling portion of the orifice plate 10 into the needle accommodation hole.

  The nozzle cylinder 8 is integrally provided with an annular step which is opposed to the annular step on the outer periphery of the needle 1 with a predetermined axial distance (needle maximum lift amount) therebetween. This annular step constitutes a needle stopper for restricting further movement when the needle 1 is fully lifted. The nozzle cylinder 8 is integrally provided with an annular step which is opposed to the valve seat surface of the orifice plate 10 with a predetermined axial distance (plate accommodation chamber) therebetween. This annular step constitutes a valve stopper for restricting further movement when the control plate 6 is fully lifted.

The valve body 9 is sandwiched between the contact surface of the nozzle body 2 and the contact surface of the injector body 4 together with the orifice plate 10.
The valve body 9 is formed with a high-pressure channel hole 32 that communicates the high-pressure channel hole 31 of the injector body 4 with the high-pressure channel hole 33 of the orifice plate 10. The valve body 9 is formed with a control valve chamber 13 that movably accommodates the control valve 11 and the valve spring 12. Further, the valve body 9 is formed with a through hole 58 that communicates with the spring accommodating chamber 55 of the injector body 4 and the control valve chamber 13 through the low pressure port 16 and extends straight in the plate thickness direction of the valve body 9. ing. The valve body 9 is formed with a communication port 19 that always communicates the control valve chamber 13 and the common flow path hole 45.
The control valve chamber 13 is a concave groove that opens from the lower end surface of the valve body 9 and extends from the opening side to the back side.

The orifice plate 10 is formed with a valve seat surface (valve seat) 59 that faces the flow passage gap 48 and on which the control plate 6 can be seated.
The orifice plate 10 is formed with a high-pressure channel hole 33 that communicates the high-pressure channel hole 32 of the valve body 9 and the fuel channel 34 of the nozzle body 2. Further, a common flow path hole 45 extending straight in the thickness direction of the orifice plate 10 is formed through the central axis of the orifice plate 10. The orifice plate 10 is formed with a high-pressure flow path hole 42, an in-orifice hole 43, and a high-pressure port 18 that communicate the high-pressure communication path 41 and the control valve chamber 13.

  The upstream end of the high-pressure channel hole 42 opens at the lower end surface of the orifice plate 10 shown in the figure. The downstream end of the high-pressure port 18 opens at the upper end surface of the orifice plate 10 shown in the figure. Further, the upstream end or the downstream end of the common flow path hole 45 opens at the upper end surface of the orifice plate 10 shown in the figure, and communicates with the control valve chamber 13. Further, the downstream end or the upstream end of the common channel hole 45 opens at the lower end surface (valve seat surface 59) of the orifice plate 10 and communicates with the channel gap 48 or the out-orifice hole 52.

Next, details of the actuator 3 will be briefly described with reference to FIGS. 1 to 3.
The actuator 3 includes a piezoelectric element laminate in which a large number of piezoelectric elements that expand and contract in the axial direction due to charge and discharge are stacked in the axial direction, a cylindrical insulating sleeve that protects the piezoelectric element laminate, and a piezoelectric element laminate And an insulating substrate provided at both ends in the axial direction of the body. The actuator 3 is configured such that a piezo drive signal (piezo applied voltage or piezo drive current) is applied between a pair of piezo lead terminals from a piezo drive circuit (EDU: not shown).

  When a voltage is applied from the EDU to the piezoelectric element stack in response to an injector valve opening drive command (injection start command) given from the ECU to the EDU, the actuator 3 charges the piezoelectric element stack. Is charged. In response to an injector valve closing drive command (injection end command) given from the ECU to the EDU, the actuator 3 stops the piezo element stack when the voltage application from the EDU to the piezo element stack is stopped (energization stop OFF). Charges are discharged from the body.

Here, in the injector provided with the piezoelectric element laminate, the actuator 3 and the control valve 11 are provided for the purpose of compensating for the shortage of the displacement amount (extension amount) with respect to the magnitude of the driving force, which is a feature of the piezoelectric element laminate. A displacement enlarging mechanism is provided between the piezoelectric piston 21 and the valve piston 22 so that the extension displacement of the actuator 3 is enlarged and transmitted to the valve piston 22 in accordance with the pressure receiving area ratio between the piezoelectric piston 21 and the valve piston 22.
The displacement enlarging mechanism includes a piezo piston (large diameter piston) 21 that moves integrally with the actuator 3 in response to expansion / contraction displacement (extension / contraction) of the actuator 3, and a valve piston (small diameter piston) that is connected to the control valve 11 so as to be able to reciprocate integrally. ) 22 and an oil tight chamber 23 filled with hydraulic oil (fuel). The displacement enlarging mechanism is configured such that the valve piston 22 indirectly drives the control valve 11 in the substantially same direction as the displacement direction of the actuator 3.

The displacement enlarging mechanism includes drive transmission members 61 and 62 that transmit the extension displacement of the actuator 3 to the piezo piston 21, a piezo spring 63 in which a thin metal plate having a large number of slit holes is formed into a cylindrical shape, the piezo piston 21 and the valve piston 22. And a displacement transmitting member that transmits the displacement of the valve piston 22 to the control valve 11 and switches the control valve 11 from the low pressure seat (state) side to the high pressure seat (state) side. (Hereinafter referred to as a displacement transmission pin) 65.
The displacement enlarging mechanism expands the displacement of the actuator 3 and the piezo piston 21 (reducing the driving force) and increases the displacement of the actuator 3 and the piezo piston 21 by increasing the fuel pressure (oil pressure) in the oil-tight chamber 23 due to the extension displacement of the actuator 3. The control valve 11 is switched and driven by the displacement of the valve piston 22.

  The piezo piston 21 is driven together with the drive transmission members 61 and 62 toward one side (tip side) in the axial direction of the piezo accommodation hole when the actuator 3 is energized (ON). The piezo piston 21 has a piston sliding portion that can reciprocate with respect to the hole wall surface of the guide hole (large diameter cylinder hole) of the piston cylinder 64. The illustrated lower end surface of the piston sliding portion is an annular piezo-side pressure receiving surface that receives the oil pressure in the oil tight chamber 23.

The valve piston 22 is driven toward the distal end side in the axial direction of the piezoelectric housing hole when the actuator 3 is energized (ON). The valve piston 22 includes a piston sliding portion that can reciprocate with respect to a hole wall surface of a guide hole (small diameter cylinder hole) of the piston cylinder 64, a piston shaft portion that extends from the piston sliding portion to one end side, and An annular flange 66 is provided on the outer periphery of the tip of the piston shaft. The illustrated upper end surface of the piston sliding portion is an annular valve side pressure receiving surface that receives the oil pressure in the oil tight chamber 23.
The pressure receiving area of the valve piston 22 is smaller than the pressure receiving area of the piezo piston 21.

The oil tight chamber 23 is an annular space surrounded by the piezoelectric side pressure receiving surface of the piezoelectric piston 21, the valve side pressure receiving surface of the valve piston 22, and the inner peripheral surface of the piston cylinder 64.
The valve piston spring 24 is a coil spring that generates a biasing force (Fsp) that biases the valve piston 22 in the valve opening direction of the control valve 11. The valve piston spring 24 is a compression coil spring disposed in a state of being compressed in the axial direction between a spring seat portion on the back side of the spring accommodating chamber 55 and a flange portion 66 (spring seat portion) of the valve piston 22. is there. Further, the valve piston spring 24 is accommodated in the spring accommodating chamber 55.

The piezo spring 63 is a slit spring that is installed between the outer peripheral protrusion 67 of the piezo piston 21 and an annular ring member 68 fixed to the piston cylinder 64 and applies a preset load to the piezo element stack. The piezo spring 63 is installed in the low pressure flow path 57 of the injector body 4.
In order to prevent the piston cylinder 64 from sticking due to the volume change (breathing action) of the lower end side of the valve piston 22 and the spring accommodating chamber 55 that accommodates the valve piston spring 24 when the actuator 3 is expanded and contracted, For the purpose of securing a hydraulic oil supply path in the spring accommodating chamber 55 from the outside of the cylindrical peripheral wall of the piezo piston 21, a plurality of radial communication holes 56 communicating with the inside and the outside of the cylindrical peripheral wall are formed. That is, the plurality of radial communication holes 56 communicate with the low-pressure channel 57. Note that the low-pressure channel 57 communicates with the outlet port of the injector body 4.

The displacement transmission pin 65 has a substantially cylindrical shape and is installed so as to penetrate the through hole 58 of the valve body 9. The upper end side of the displacement transmission pin 65 in the figure protrudes into the spring accommodating chamber 55 from the upper end face in the figure of the valve body 9, and the upper end face in the figure is in direct contact with the distal end surface of the flange 66 of the valve piston 22. In contact. Further, the lower end side of the displacement transmission pin 65 in the figure protrudes into the control valve chamber 13 of the valve body 9, and the lower end face in the figure directly contacts or contacts the bottom surface of the concave groove of the control valve 11 of the control valve. ing.
The displacement transmission pin 65 transmits the displacement of the valve piston 22 in the valve opening direction, that is, the driving force to the one side in the axial direction by the displacement enlarging mechanism to the control valve 11 of the control valve, and the flange 66 of the valve piston 22. The urging force of the valve piston spring 24 applied to the control valve 11 is transmitted to the control valve 11. That is, the valve piston 22 forcibly opens the control valve 11 via the displacement transmission pin 65.

Next, the details of the control valve of the three-way valve structure of this embodiment will be briefly described with reference to FIGS.
The control valve includes a control valve 11 that is forcibly opened by the valve piston 22 via a displacement transmission pin 65, a valve spring 12 that urges the control valve 11 in the valve closing direction, and the like. The body 9 is accommodated in the control valve chamber 13 so as to be reciprocally movable.
The control valve 11 communicates the high pressure port 18 with the communication port 19 and blocks the communication between the low pressure port 16 and the communication port 19, communicates the low pressure port 16 with the communication port 19, and communicates with the high pressure port 18. It is a valve body that selectively switches between a high-pressure seal state that blocks communication of the communication port 19.

The control valve 11 is in contact with and separated from the low pressure seat surface 15 of the valve body 9 to open and close the low pressure port 16, and the high pressure port 18 is in contact with and separated from the high pressure seat surface 17 of the orifice plate 10. A high pressure side valve portion (second valve body) 72 that opens and closes, a flange portion (large diameter portion) 74 that is provided on the back side (the lower side in the drawing) of the low pressure side valve portion 71 and serves as a working surface of the valve spring 12, Further, it has a valve shaft portion (small diameter portion) 75 or the like that protrudes from the back side (the lower side in the drawing) of the flange portion 74 and has an outer diameter smaller than that of the flange portion 74.
A sliding portion (surface) that can slide back and forth with respect to the hole wall surface of the guide hole (cylinder hole) of the valve body 9 may be provided on the outer periphery of the flange portion 74. In this case, a guide hole (cylinder hole) is provided in the wall surface of the control valve chamber 13 of the valve body 9 to support the sliding portion of the flange portion 74 so as to be slidable back and forth.

The low-pressure side valve portion 71 has a low-pressure seal surface having a planar shape (or a convex curved surface shape (partial spherical surface)) seated on the low-pressure seat surface 15. The low pressure side valve portion 71 protrudes upward in the figure from the center portion of the flange portion 74.
The high-pressure side valve portion 72 has a planar high-pressure seal surface that is seated on the high-pressure seat surface 17.
A low pressure seal surface of the low pressure side valve portion 71 is provided on one end surface (the upper end surface in the drawing) of the valve shaft portion 75 in the axial direction (reciprocating direction). Further, a high pressure seal surface of the high pressure side valve portion 72 is provided on the other end surface (the lower end surface in the drawing) of the valve shaft portion 75 in the axial direction (reciprocating direction).
The low-pressure seat surface 15 is disposed opposite to the high-pressure seat surface 17 with a predetermined axial distance (height dimension of the control valve chamber 13).

The valve spring 12 is accommodated in the control valve chamber 13 so as to be reciprocally movable. This valve spring 12 generates a biasing force (Fsp) that biases the control valve 11 in a direction to switch the control valve 11 from the high pressure seat (state) side to the low pressure seat (state) side. Means (elastic member).
Further, the valve spring 12 is disposed in a state compressed in the axial direction between the spring seat portion on the back side of the control valve chamber 13 of the valve body 9 and the flange portion 74 (spring seat portion) of the control valve 11. It is a compression coil spring.

Here, the control valve is forcibly switched from the low-pressure seat side to the high-pressure seat side (valve opening drive) by the valve piston 22 that receives the extension displacement of the actuator 3 when the actuator 3 is energized (the valve spring 12 of the valve spring 12). Pushed down against the force).
As a result, the low pressure side valve portion 71 is separated (lifted) from the low pressure seat surface 15 to open the low pressure port 16, and the high pressure side valve portion 72 is seated (seat) on the high pressure seat surface 17 to close the high pressure port 18. As a result, the fuel in the pressure control chamber 14 passes through the low-pressure fuel passage such as the low-pressure port 16 through the flow path hole 51, the out-orifice hole 52, the common flow path hole 45, the communication port 19, and the control valve chamber 13. To the low pressure side of the fuel system. As a result, the fuel pressure in the pressure control chamber 14 quickly decreases, and when the fuel pressure in the pressure control chamber 14 decreases to the needle valve opening pressure (Po), the needle 1 starts the valve opening operation and the cylinder of the engine High pressure fuel is injected into the combustion chamber.

The control valve is switched from the high-pressure seat side to the low-pressure seat side (valve-closing drive) by the urging force of the valve spring 12 when the energization of the actuator 3 is stopped.
As a result, the low pressure side valve portion 71 is seated (seat) on the low pressure seat surface 15 to close the low pressure port 16, and the high pressure side valve portion 72 is separated (lifted) from the high pressure seat surface 17 to open the high pressure port 18. As a result, high-pressure fuel is introduced into the pressure control chamber 14 from the high-pressure port 18 through the control valve chamber 13, the communication port 19, the common channel hole 45, the channel gap 48 and the communication channel 49. As a result, the fuel pressure in the pressure control chamber 14 rises quickly, and when the fuel pressure in the pressure control chamber 14 recovers to the needle valve closing pressure (Pc), the needle 1 starts the valve closing operation, and the engine cylinder The fuel injection into the combustion chamber ends.

  Next, details of the control plate 6 of this embodiment will be briefly described with reference to FIGS. Here, the injector of the present embodiment is configured such that the pressure control chamber passes through the in-orifice hole 43 through the high-pressure port 18, the control valve chamber 13, the communication port 19, the common channel hole 45, the channel gap 48 and the communication channel 49. 14 through the first introduction path (FL1) for introducing the high-pressure fuel to the inlet 14, the in-orifice hole 38, the passage gap 48 and the communication passage 49, and the high-pressure port 18, the control valve chamber 13, the communication port 19, and the common flow. A second introduction path for bypassing the passage hole 45 to introduce high-pressure fuel into the pressure control chamber 14, a fully open position for opening the second introduction path (particularly the in-orifice hole 38), and a second introduction path (particularly the in-orifice hole 38). And a pressure-actuated control plate 6 that can be displaced in two positions, ie, a fully closed position.

The in-orifice hole 38 is provided upstream of the pressure control chamber 14 and the flow passage gap 48 in the fuel flow direction. The in-orifice hole 38 is provided on the second introduction path, and is arranged in parallel with the control valve chamber 13 and the common flow path hole 45.
The in-orifice hole 43 is provided upstream of the control valve chamber 13, the pressure control chamber 14, and the flow passage gap 48 in the fuel flow direction. The in-orifice hole 43 is provided on the first introduction path, and is arranged in series with the control valve chamber 13 and the common flow path hole 45.

The control plate 6 corresponds to an “open / close valve” in the claims. The control plate 6 is a flat plate valve having a predetermined thickness, and when the fuel flows from the pressure control chamber 14 to the common flow path hole 45, the fuel path in the injector is switched to the first fuel path. When the high-pressure fuel is introduced into the pressure control chamber 14 from the common flow path hole 45, it also functions as a two-position switching valve that switches the fuel path in the injector to the second fuel path.
The first fuel path is a fuel discharge path through which fuel flows out from the pressure control chamber 14 to the common flow path hole 45 via the flow path hole 51 and the out orifice hole 52. In addition, the second fuel path means that the high-pressure fuel is supplied to the pressure control chamber 14 from the common flow path hole 45 via the flow path gap 48 and the communication flow path 49 and bypassing the flow path hole 51 and the out orifice hole 52. This is a fuel introduction route to be introduced.

  The control plate 6 is accommodated in a reciprocating manner in the upper part of the pressure control chamber 14 (a space formed between the valve seat surface 59 of the orifice plate 10 and the annular step of the nozzle cylinder 8: a plate accommodating chamber). . Further, the control plate 6 has a difference in vertical pressure received by the control plate 6, that is, a fuel pressure (upper pressure) in the common flow path hole 45 (or flow path gap 48) and a fuel pressure (lower part) in the pressure control chamber 14. This is a floating valve (plate) that reciprocates in the axial direction of the injector (the vertical direction in the figure) in accordance with the pressure difference from the pressure.

  The upper end surface of the control plate 6 shown in the figure is in close contact with the valve seat surface 59 of the orifice plate 10 or opposed with a predetermined flow passage gap 48 therebetween, and the fuel pressure in the common flow passage hole 45 (or the flow passage gap 48) is controlled. A valve-opening pressure receiving surface for receiving pressure is provided. A valve-side pressure receiving surface that faces the pressure control chamber 14 and receives the fuel pressure in the pressure control chamber 14 is provided on the lower end surface of the control plate 6 in the figure. In addition, a flow path hole 51 and an out orifice hole 52 are formed through the central axis of the control plate 6.

The channel hole 51 is opened at the lower end surface of the control plate 6 shown in the figure. Further, the out-orifice hole 52 is opened at the upper end surface of the control plate 6 in the figure.
The flow path gap 48 is a variable volume space formed between the valve-opening pressure receiving surface of the control plate 6 and the valve seat surface 59 of the orifice plate 10. The fuel pressure introduced into the flow path gap 48 is a valve opening direction oil pressure (FO) that acts on the control plate 6 as a biasing force that biases the control plate 6 in the valve opening direction.

The control plate spring 7 is accommodated in the pressure control chamber 14 together with the control plate 6. The control plate spring 7 is an elastic member that generates a biasing force (elastic force, spring set load) that biases the control plate 6 in the valve closing direction of the control plate 6.
The control plate spring 7 is compressed in the axial direction between the valve-closing pressure receiving surface (spring seat portion) of the control plate 6 and the bottom surface (spring seat portion) on the back side of the accommodation recess of the needle 1. It is a compression coil spring arranged.

  In the injector of the present embodiment, the valve opening direction oil pressure (FU) received by the valve opening side pressure receiving surface of the control plate 6 is the valve closing direction oil pressure (FL) received by the valve closing side pressure receiving surface of the control plate 6. When the resultant force is larger than the resultant force of the control plate spring 7 in the valve closing direction (Fsp), the control plate 6 is detached from the valve seat surface 59 of the orifice plate 10. At this time, a flow passage gap 48 through which the high-pressure fuel introduced from the common flow passage hole 45 can flow is formed between the upper end surface of the control plate 6 and the valve seat surface 59 of the orifice plate 10.

  Further, in the injector, the valve opening direction oil pressure (FU) received by the valve opening side pressure receiving surface of the control plate 6 is the valve closing direction oil pressure (FL) received by the valve closing side pressure receiving surface of the control plate 6 and the control plate. When the resultant force is smaller than the resultant force with the biasing force (Fsp) in the valve closing direction of the spring 7, the illustrated upper end surface (valve portion) of the control plate 6 is seated (contacted) on the valve seat surface 59 of the orifice plate 10. At this time, the pressure control chamber 14 and the common flow path hole 45 communicate with each other through the flow path hole 51 and the out orifice hole 52.

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

Here, in the injector of this embodiment, the throttle diameter is set so that the flow rate of the in-orifice hole 43 (in-orifice flow rate) is larger than the flow rate of the out-orifice hole 52 (out-orifice flow rate). Yes. As a result, the rate of increase of the fuel pressure in the pressure control chamber 14 at the time of the low pressure seat of the control valve is higher than the rate of decrease of the fuel pressure in the pressure control chamber 14 at the time of the high pressure seat of the control valve (control chamber pressure). The slope of the waveform and injection rate waveform is steep).
Further, the throttle diameter is set so that the passage flow rate (main in-orifice flow rate) of the in-orifice hole 38 is larger than the passage flow rate (sub-in-orifice flow rate) of the in-orifice hole 43. The throttle diameter may be set so that the passage flow rate (sub-in-orifice flow rate) of the in-orifice hole 43 is larger than the passage flow rate (main-in-orifice flow rate) of the in-orifice hole 38.

When the engine is started, high pressure is applied from the high pressure part of the fuel system such as a supply pump or common rail to the inside of the injector (high pressure fuel passage) via the high pressure pipe (high pressure fuel supply pipe) and the inlet port of the injector body 4. The fuel is introduced.
A part of the high-pressure fuel introduced into the injector passes from the inlet port of the injector body 4 to the fuel reservoir chamber 26 and the fuel channel 36 through the high-pressure channel holes 31 to 33 and the fuel channels 34 and 35. To reach.
On the other hand, a part of the high-pressure fuel flowing through the high-pressure channel holes 31 to 33 branches from the branch portion between the high-pressure channel holes 32 and 33, passes through the high-pressure channel hole 37 and the in-orifice hole 38, and the control plate 6 To the upper end surface shown in the figure.

Here, when no voltage is applied to the piezoelectric element laminate of the actuator 3 and the control valve 11 is urged toward the low-pressure seat by the urging force of the valve spring 12 and the high-pressure port 18 is opened, the high-pressure port 18 is opened. The remainder of the fuel branches off from the branch portion (high pressure communication path 41) between the high pressure flow path holes 32 and 33, and the high pressure flow path hole 42, in-orifice hole 43, high pressure port 18, control valve chamber 13, communication port 19 and It reaches the illustrated upper end surface of the control plate 6 through the common flow path hole 45.
At this time, since the control valve 11 closes the low pressure port 16, the outflow of fuel from the pressure control chamber 14 to the low pressure side of the fuel system via the low pressure fuel passage is stopped. As a result, the fuel pressure (valve opening direction oil pressure: FO) in the common channel hole 45 and the channel gap 48 is changed between the fuel pressure in the pressure control chamber 14 (valve closing direction oil pressure: FC) and the control plate spring 7. And the resultant force (valve closing direction biasing force: Fsp).

As a result, the control plate 6 is lifted (detached) from the valve seat surface 59 of the orifice plate 10, and a predetermined flow path gap 48 is formed between the control plate 6 and the illustrated upper end surface. That is, the control plate 6 is switched to the fully open position where the fuel path in the injector is switched to the second fuel path and the second introduction path (in-orifice hole 38) is opened.
At this time, the high-pressure fuel that has reached the in-orifice hole 38 and the common channel hole 45 is introduced into the channel gap 48 from the in-orifice hole 38 and the common channel hole 45. Since the high-pressure fuel introduced into the flow passage gap 48 is introduced into the pressure control chamber 14 through the flow passage gap 48 and the communication flow passage 49, the fuel pressure in the pressure control chamber 14 (valve closing direction). Oil pressure (FC) increases.

Further, the needle 1 has a fuel pressure in the fuel reservoir chamber (valve opening direction oil pressure: FO), a fuel pressure in the pressure control chamber 14 (valve closing direction oil pressure: FC), and a spring set of the needle spring 5. A load (valve closing direction urging force: Fsp) is acting, and FO <FC + Fsp is established.
As a result, no voltage is applied to the piezoelectric element laminate of the actuator 3, and the control valve 11 is urged toward the low pressure seat by the urging force of the valve spring 12 to close the low pressure port 16 and open the high pressure port 18. Since the valve portion of the needle 1 is seated (seat) on the needle seat surface of the nozzle body 2 during the low pressure seat state, the cylinder that communicates the fuel reservoir chamber 26 with the plurality of injection holes 27 The fuel flow path 36 is blocked.

Therefore, in the injector, since the needle 1 maintains the valve closed state, fuel injection into the combustion chamber of the cylinder of the engine is not performed.
The fuel pressure (valve opening oil pressure: FO) in the common channel hole 45 and the channel gap 48 and the fuel pressure (valve closing oil pressure: FC) in the pressure control chamber 14 are balanced. Regardless of the presence or absence of the control plate spring 7, the control plate 6 moves in the valve closing direction while being guided by the guide hole of the nozzle cylinder 8 and is seated (seat) on the valve seat surface 59 of the orifice plate 10. Thereby, the flow path gap 48 between the illustrated upper end surface of the control plate 6 and the valve seat surface 59 is eliminated (or narrowest). That is, the control plate 6 is switched to the fully closed position where the fuel path in the injector is switched to the first fuel path and the second introduction path (in-orifice hole 38) is closed.

When it becomes the injection timing of the injector of the cylinder of the engine and the application of voltage to the piezo element stack of the actuator 3 is started by the injector valve opening drive command from the ECU, the piezo element stack is charged. When the piezo charging energy reaches a predetermined value, the piezo element stack starts to be extended and displaced to one side in the axial direction. Accordingly, the piezo piston 21 is driven to one side in the axial direction via the drive transmission members 61 and 62.
As described above, when the piezoelectric element stack of the actuator 3 is extended and displaced, the volume of the oil-tight chamber 23 is reduced and the fuel pressure (oil pressure) in the oil-tight chamber 23 is increased as the piezo piston 21 moves (displaces). To do. When the oil pressure in the oil tight chamber 23 rises, the valve piston 22 is assisted by the urging force of the valve piston spring 24 while being substantially in the same direction as the displacement direction of the actuator 3, that is, the control valve 11 is opened. Driven in the valve direction.

Since the displacement transmission pin 65 is in contact with the tip of the valve piston 22, the displacement transmission pin 65 pushes down the control valve 11 of the control valve in accordance with the movement (displacement) of the valve piston 22.
For this reason, since the control valve 11 is forcibly opened by the valve piston 22, the low pressure side valve portion 71 of the control valve 11 separates (lifts) from the low pressure seat surface 15, and the high pressure side valve of the control valve 11 The part 72 is seated (seat) on the high-pressure seat surface 17. As a result, the low pressure port 16 is opened and the high pressure port 18 is closed.

On the other hand, since the control plate 6 is maintained in the fully closed state, the fuel in the pressure control chamber 14 passes through the flow path hole 51 and the out-orifice hole 52 provided on the central axis of the control plate 6, and the orifice. It flows into the common channel hole 45 of the plate 10.
The fuel that has flowed into the common channel hole 45 flows into the control valve chamber 13 of the valve body 9. The fuel that has flowed into the control valve chamber 13 flows into the low pressure passage hole 54 from the low pressure port 16.
Then, the fuel that has flowed into the low pressure passage hole 54 flows out of the injector from the outlet port through the spring accommodating chamber 55, the plurality of radial communication holes 56, and the low pressure passage 57 to the low pressure side of the fuel system. Discharged.

Thereafter, when FO> FC + Fsp is established, the fuel pressure in the fuel reservoir chamber 26 (valve opening direction oil pressure: FO) is changed between the fuel pressure in the pressure control chamber 14 (valve closing direction oil pressure: FC) and the needle spring 5. It exceeds the resultant force with the spring set load (valve closing direction biasing force: Fsp). That is, when the fuel pressure in the pressure control chamber 14 decreases to the needle valve opening pressure (Po), the needle 1 starts to rise (lift) by the fuel pressure in the fuel reservoir chamber 26.
As a result, since the needle 1 is separated (lifted) from the needle seat surface, the needle 1 is opened, and fuel injection from the plurality of injection holes 27 into the combustion chamber of the engine cylinder is started.

Thereafter, when an injector valve opening period (a command injection period calculated from the fuel injection amount and the command injection pressure in the ECU, which corresponds to the energization period for the actuator 3) elapses from the injection timing, the injection end timing is reached. Outputs an injector valve closing drive command.
When the voltage application from the EDU to the piezo element stack is stopped (energization stop OFF) in response to the injector valve closing drive command, the electric charge is discharged from the piezo element stack. Along with this, the piezoelectric element stack is contracted and displaced, and the piezoelectric piston 21 and the drive transmission members 61 and 62 are pushed back by the urging force of the piezoelectric spring 63.

Further, in the injector, when the actuator 3 is contracted and displaced, the piezo piston 21 is returned to the initial position, so that the volume of the oil-tight chamber 23 is expanded and the oil pressure in the oil-tight chamber 23 is reduced (dropped). When the oil pressure in the oil tight chamber 23 decreases, the valve piston 22 resists the urging force of the valve piston spring 24 and is substantially in the same direction as the displacement direction of the actuator 3, that is, the control valve 11 is closed. Driven in the direction. That is, as the oil pressure in the oil tight chamber 23 decreases, the control valve 11, the valve piston 22 and the displacement transmission pin 65 are pushed back (pushed up) by the urging force of the valve spring 12.
Accordingly, the low pressure side valve portion 71 of the control valve 11 is seated (seat) on the low pressure seat surface 15, and the high pressure side valve portion 72 of the control valve 11 is separated (lifted) from the high pressure seat surface 17. Thereby, the low pressure port 16 is closed and the high pressure port 18 is opened.

As described above, when the low pressure side valve portion 71 of the control valve 11 closes the low pressure port 16, the outflow of fuel from the pressure control chamber 14 to the low pressure side of the fuel system via the control valve chamber 13. Stops.
On the other hand, since the high-pressure side valve portion 72 of the control valve 11 opens the high-pressure port 18, the high-pressure fuel introduced into the high-pressure flow path holes 31 to 33 from the outside of the injector flows into the high-pressure communication path 41, the high-pressure flow. The upper end surface of the control plate 6 is reached from the passage hole 42, the in-orifice hole 43, the high-pressure port 18, the control valve chamber 13, and the common flow path hole 45. Further, a part of the high-pressure fuel flowing through the high-pressure channel holes 31 to 33 is branched from a branch portion between the high-pressure channel holes 32 and 33, passes through the high-pressure channel hole 37 and the in-orifice hole 38, and the control plate 6. To the upper end surface of the figure.
As a result, the fuel pressure (valve opening oil pressure: FO) in the in-orifice hole 38, the common channel hole 45 and the channel gap 48 is changed to the fuel pressure (valve closing direction oil pressure: FC) in the pressure control chamber 14. And the resultant force of the control plate spring 7 (valve closing direction biasing force: Fsp).

As a result, the control plate 6 is lifted (detached) from the valve seat surface 59 of the orifice plate 10, and a predetermined flow path gap 48 is formed between the control plate 6 and the illustrated upper end surface. That is, the control plate 6 is switched to the fully open position where the fuel path in the injector is switched to the second fuel path and the second introduction path (in-orifice hole 38) is opened.
At this time, the high-pressure fuel that has reached the in-orifice hole 38 and the common channel hole 45 is introduced into the channel gap 48 from the common channel hole 45. Since the high-pressure fuel introduced into the flow passage gap 48 is introduced into the pressure control chamber 14 through the flow passage gap 48 and the communication flow passage 49, the fuel pressure in the pressure control chamber 14 (the valve closing direction). Oil pressure (FC) recovers rapidly.

Then, the vertical pressure difference of the needle 1 decreases, and FO <FC + Fsp is established. That is, when the fuel pressure in the pressure control chamber 14 recovers to the needle valve closing pressure (Pc), the needle 1 moves in the valve closing direction and the valve portion of the needle 1 is seated on the needle seat surface of the nozzle body 2 (seat). To do.
Therefore, the cylindrical fuel flow path 36 that communicates the fuel reservoir chamber 26 and the plurality of injection holes 27 is blocked, so that the fuel injection from the injection holes 27 of the injector into the combustion chamber of the engine cylinder ends.

[Effect of Example 1]
As described above, in the injector of the present embodiment, the control valve 11 is switched to the high-pressure seal state against the biasing force of the valve spring 12 by the driving force of the actuator 3, and the control plate 6 is connected to the second introduction path (FL2). ) Is closed to the fully closed position, the introduction of fuel into the pressure control chamber 14 is interrupted, and the fuel flows out from the pressure control chamber 14. As a result, fuel flows out from the pressure control chamber 14 to the low pressure side of the fuel system via the communication port 19, the control valve chamber 13, the low pressure port 16 and the low pressure fuel passage (54 to 57). Fuel pressure decreases. When the fuel pressure in the pressure control chamber 14, that is, the fuel pressure acting on the needle 1 in the valve closing direction decreases to the needle opening pressure, the needle 1 opens (lifts) and the combustion chamber of the cylinder of the engine The fuel injection to is started.
At this time, the needle opening speed is set by the fuel flow rate (out-orifice flow rate) defined by the out-orifice hole 52.

On the other hand, when the control valve 11 is switched to the low pressure sealing state by the urging force of the valve spring 12 and the control plate 6 is displaced to the fully open position that opens the second introduction path (FL2), the fuel is introduced into the pressure control chamber 14. Thus, the outflow of fuel from the pressure control chamber 14 is blocked. As a result, high-pressure fuel is introduced from the high-pressure fuel passage into the pressure control chamber 14 via the first introduction path, and from the high-pressure fuel passage through the second introduction path, and to the control valve chamber 13 and the common passage hole 45. The high pressure fuel is introduced into the pressure control chamber 14 by bypassing the pressure, and the fuel pressure in the pressure control chamber 14 increases. When the fuel pressure in the pressure control chamber 14, that is, the fuel pressure acting in the valve closing direction on the needle 1 rises to the needle valve closing pressure, the needle 1 is closed (seat) and the combustion chamber of the cylinder of the engine The fuel injection to is finished.
At this time, the needle valve closing speed is set by the fuel flow rate defined by the in-orifice hole 38 and the in-orifice hole 43 (main in-orifice flow rate + sub-in-orifice flow rate).

Therefore, even when the out-orifice flow rate is increased, the fuel injection rate is improved, or the fuel injection pressure is increased, the advantage of the control plate 6 is utilized, and the in-orifice holes 38, 43 are used. By dividing into two, the desired needle valve closing speed can be realized with the total flow rate of the two in-orifice holes 38 and 43, so that the high-pressure seat load on the control valve 11 of the control valve can be reduced. As a result, the needle valve opening speed and the needle valve closing speed can be improved without increasing the driving force of the actuator 3. Thereby, the on-off valve responsiveness of the needle can be improved.
Further, since the main in-orifice flow rate directly above the control plate 6 can be reduced as compared with the conventional injector using the control plate, the pressure drop in the pressure control chamber 14 is increased particularly in the proximity multistage injection, and the injection response. As a result, stable multi-injection at short intervals can be realized.

Here, in a conventional injector, a three-way valve is provided in a hydraulic control chamber (including a control chamber, a common flow channel, a control valve chamber, an upstream end of a low pressure fuel passage, etc.) from the pressure receiving surface of the needle to the out orifice. Since the control valve (valve element, coil spring, etc.) having the structure is accommodated, the volume of the hydraulic control chamber is increased.
When the volume of the hydraulic control chamber increases, when the injector injection start command is issued, the displacement of the actuator is used to push down the valve body of the control valve so that the valve body of the control valve is seated on the high pressure seat. When the fuel pressure rapidly drops from a high pressure equivalent to the fuel injection pressure, the bulk modulus of the fuel greatly fluctuates. Along with this, the fuel volume pulsation is generated in the hydraulic control chamber as the volume of the fuel repeatedly expands and contracts.

In particular, when the out-orifice flow rate is increased for the purpose of reducing the fuel pressure in the hydraulic control chamber at a high speed and improving the valve opening response of the needle, the amplitude of the pressure pulsation in the hydraulic control chamber becomes larger, When the needle starts to lift, the needle may lift while wobbling. Thereby, since the controllability of the needle is deteriorated, there arises a problem that the control accuracy of the injection amount with respect to the injection amount command value (energization length) is deteriorated.
As a result, it is difficult to increase the needle opening speed, and the valve opening response of the needle cannot be improved. In order to open the needle at a high speed, it is necessary to quickly reduce the fuel pressure in the hydraulic control chamber.

In view of this, the injector of the present embodiment is provided with an out-orifice hole 52 in the control plate 6 positioned upstream of the control valve chamber 13, and the control plate 6 is disposed in the pressure control chamber 14, thereby providing hydraulic pressure. Since the control chamber volume is reduced, the pressure pulsation in the pressure control chamber 14 can be reduced. Moreover, even when the out-orifice flow rate is increased, the pressure pulsation in the pressure control chamber 14 can be reduced for the purpose of improving the valve opening response of the needle 1 by reducing the fuel pressure in the pressure control chamber 14 at high speed. .
Therefore, it is possible to prevent the needle 1 from lifting while undulating during the needle valve opening operation. Thereby, since the valve opening operation of the needle 1 is stabilized from the start of the lift to the full lift, the deterioration of the controllability of the needle 1 and the deterioration of the control accuracy of the injection amount can be suppressed.

  On the other hand, when voltage application to the piezoelectric element laminate of the actuator 3 is stopped (energization stop OFF), the control valve 11 is seated on the low pressure seat surface 15 to close the low pressure port 16 and the control valve 11 is closed to the high pressure seat. The high pressure port 18 is released from the surface 17 (low pressure sealed state). When the control valve is switched to the low pressure seal state in this way, the pressure is increased from the high pressure fuel passage (31 to 34, 37, 38, 41 to 43) via the high pressure port 18, the control valve chamber 13 and the common flow path hole 45. High-pressure fuel is introduced into the control chamber 14, and the fuel pressure in the pressure control chamber 14 rises (recovers).

When the fuel is introduced into the pressure control chamber 14 from the shared flow path hole 45, the control plate 6 is pushed down by the fuel pressure in the shared flow path hole 45. That is, since the control plate 6 is detached from the valve seat surface 59 of the orifice plate 10 and the control plate 6 is opened, the fuel path in the injector is switched to the second fuel path. Then, the high-pressure fuel introduced into the pressure control chamber 14 from the shared flow path hole 45 bypasses the out orifice hole 52 and is introduced into the pressure control chamber 14.
Thereby, since the fuel introduced into the pressure control chamber 14 from the common flow path hole 45 does not pass through the out orifice hole 52, the needle valve closing speed is set to the high pressure fuel passages (31 to 34, 37, 38, 41 to 43). ), The fuel flow rate (fuel flow rate defined by the in-orifice hole 43) flowing through the high-pressure port 18, the control valve chamber 13, and the common flow path hole 45.
Therefore, the needle opening speed and the needle closing speed can be set independently.

[Configuration of Example 2]
4 and 5 show a piezo 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.

The injector of the present embodiment includes out-orifice holes 52 and 53 that regulate the flow rate of fuel flowing out from the pressure control chamber 14 to the low-pressure fuel passages (53 to 57) through the common flow path hole 45 and the control valve chamber 13. ing.
The out-orifice hole 52 is a first outlet-side throttle hole (located upstream of the communication port 19 of the control valve chamber 13 in the fuel flow direction and between the flow path hole 51 and the common flow path hole 45 ( Main out orifice hole, first out orifice). The out-orifice hole 52 communicates the flow path hole 51 and the shared flow path hole 45. Further, the out-orifice hole 52 is formed on the central axis of the control plate 6.

The out-orifice hole 53 is a second outlet-side throttle hole (sub-portion) installed downstream of the low-pressure port 16 of the control valve chamber 13 in the fuel flow direction and between the low-pressure port 16 and the low-pressure channel hole 54. Out orifice hole, second out orifice). The out orifice hole 53 communicates the low pressure port 16 and the low pressure flow path hole 54.
Here, in the injector of the present embodiment, the throttle diameter is set so that the passage flow rate (sub-out orifice flow rate) of the out orifice hole 53 is larger than the flow rate of the out orifice hole 52 (main out orifice flow rate). Has been.

  Further, in the injector of this embodiment, since the out-orifice hole 53 is provided between the low pressure port 16 of the control valve chamber 13 and the low pressure passage hole 54 of the low pressure fuel passage, the control valve is opened and controlled. When the valve 11 is switched from the low-pressure seal state to the high-pressure seal state, at the moment when the low-pressure side valve portion 71 of the control valve 11 is separated (lifted) from the low-pressure seat surface 15 of the valve body 9, the valve 11 is located upstream of the out-orifice hole 53. High pressure fuel flows into the low pressure port 16 located through an annular clearance between the outside surface of the control valve 11 and the wall surface of the control valve chamber 13. In this way, a constant pressure can be maintained in the low pressure port 16 immediately above the low pressure side valve portion 71 of the control valve 11, so that the control valve 11 is biased in the direction of the high pressure port 18 (high pressure seal state) ( (Assistance: assist), and the high-pressure seat load on the control valve 11 of the control valve can be reduced.

As a result, the switching operation from the low-pressure seal state to the high-pressure seal state in the control valve 11 of the control valve is accelerated, so that the valve opening timing of the needle 1 is accelerated.
On the other hand, since a constant pressure can be maintained in the low pressure port 16 immediately above the low pressure side valve portion 71 of the control valve 11, a rapid pressure drop in the control valve chamber 13 at the initial stage of fuel injection can be suppressed. Thereby, an effect of suppressing pressure pulsation in the pressure control chamber 14 is provided.
As described above, the injector of the present embodiment has the same effects as those of the first embodiment.

[Configuration of Example 3]
6 and 7 show a piezo injector (Embodiment 3) to which the fuel injection valve of the present invention is applied.
Here, the same reference numerals as those in the first and second embodiments indicate the same configuration or function, and the description thereof will be omitted.

The injector of the present embodiment eliminates the in-orifice hole 43 of the first and second embodiments. The common flow path of the injector includes a common flow path hole 45 communicating with the communication port 19 opened at the wall surface of the control valve chamber 13, and an in (common) orifice hole (hereinafter referred to as an orifice hole) communicating with the common flow path hole 45. 46, and a common channel hole 47 that communicates the orifice hole 46 with a channel without throttle or a channel with throttle.
The orifice hole 46 is connected to the control valve chamber 13, the communication port 19, the common channel hole 45, the orifice hole 46, the common channel hole 47, the channel gap 48, and the communication channel 49 from the high pressure port 18. This is an inlet-side throttle hole that regulates the flow rate of high-pressure fuel introduced into the control chamber 14. The orifice hole 46 is a second outlet that regulates the flow rate of fuel flowing out from the pressure control chamber 14 to the low pressure side of the fuel system through the common flow path hole 45, the control valve chamber 13, and the low pressure fuel passages (54 to 57). It is a side throttle hole. In this case, the out-orifice hole 52 is a first outlet-side throttle hole.

  Here, in the injector of this embodiment, the throttle diameter is set so that the passage flow rate (in (common) orifice flow rate) of the orifice hole 46 is larger than the passage flow rate (out orifice flow rate) of the out orifice hole 52. Has been. As a result, the rate of increase of the fuel pressure in the pressure control chamber 14 at the time of the low pressure seat of the control valve is higher than the rate of decrease of the fuel pressure in the pressure control chamber 14 at the time of the control valve high pressure seat (control chamber pressure). The slope of the waveform and injection rate waveform is steep).

When the control valve is a high pressure seat, the fuel flows out from the pressure control chamber 14 through the out orifice hole 52 and the orifice hole 46 to the low pressure side of the fuel system. For this reason, since the double restriction is made when the control valve is at a high pressure, the fuel pressure in the pressure control chamber 14 on the upstream side of the out orifice hole 52 and the common flow path hole 47 on the downstream side of the out orifice hole 52 are reduced. The amount of pressure change between fuel pressure (amount of decrease, pressure difference) is smaller than that in the first embodiment. Further, by providing the out-orifice hole 52 between the pressure control chamber 14 and the orifice hole 46, the volume of the fuel discharge flow path from the pressure control chamber 14 to the orifice hole 46 is divided into two. As a result, the hydraulic control chamber volume that stores the fuel pressure acting in the valve closing direction on the needle 1 is changed from the upper end surface of the sliding portion 28 of the needle 1 and the bottom surface of the accommodating recess (the pressure receiving surface of the needle 1) to the out orifice hole. It becomes a volume up to 52 and becomes very small. Therefore, the pressure pulsation in the pressure control chamber 14 generated when the control valve 11 of the control valve is switched from the low pressure seal state to the high pressure seal state can be further reduced.
As described above, the injector of the present embodiment has the same effects as those of the first and second embodiments.

[Configuration of Example 4]
FIG. 8 shows a piezo injector (Embodiment 4) to which the fuel injection valve of the present invention is applied.
Here, the same reference numerals as in the first to third embodiments indicate the same configuration or function, and the description thereof is omitted.

The injector of the present embodiment includes a control valve having a three-way valve structure movably accommodated in a control valve chamber 13 formed between the concave groove of the valve body 9 and the upper end surface of the orifice plate 10 in the figure. Yes.
The wall surface of the valve body 9 is formed with a truncated cone (taper) cylindrical low pressure seat surface 15 on which the low pressure side valve portion 71 of the control valve 11 of the control valve can be seated (seat). A low-pressure port 16 communicating with the low-pressure channel hole 54 through the out-orifice hole 53 is formed in the concave groove extending from the back side of the low-pressure seat surface 15, that is, from the ceiling surface of the control valve chamber 13. Yes.
A planar high pressure seat surface 17 on which the high pressure side valve portion 72 of the control valve 11 can be seated (seat) is formed on the upper end surface of the orifice plate 10 in the figure. A high-pressure port 18 that communicates with the high-pressure channel hole 42 through the in-orifice hole 43 is formed at the center of the high-pressure sheet surface 17.

The control valve includes a control valve 11 that is forcibly opened by the valve piston 22 via a displacement transmission pin 65, a valve spring 12 that urges the control valve 11 in the valve closing direction, and the like. The body 9 is accommodated in the control valve chamber 13 so as to be reciprocally movable.
The control valve 11 includes a low pressure side valve portion 71, a high pressure side valve portion 72, a flange portion 74, a valve shaft portion 75, and the like.
The low pressure side valve portion 71 has a low pressure sealing surface having a convex curved surface (partial spherical surface) that is seated on the low pressure seat surface 15.
The high-pressure side valve portion 72 has a planar high-pressure seal surface that is seated on the high-pressure seat surface 17.
As described above, the injector of the present embodiment has the same effects as those of the first to third embodiments.
The structure of the control valve 11 of the control valve of this embodiment and the structure of the low-pressure seat surface 15 of the control valve chamber 13 may be incorporated in the first to third embodiments.

[Configuration of Example 5]
FIG. 9 shows a piezo injector (Embodiment 5) to which the fuel injection valve of the present invention is applied.
Here, the same reference numerals as in the first to fourth embodiments indicate the same configuration or function, and the description thereof is omitted.

The injector of the present embodiment includes a control valve having a three-way valve structure movably accommodated in a control valve chamber 13 formed between the concave groove of the valve body 9 and the upper end surface of the orifice plate 10 in the figure. Yes.
The wall surface of the valve body 9 is formed with a truncated cone (taper) cylindrical low pressure seat surface 15 on which the low pressure side valve portion 71 of the control valve 11 of the control valve can be seated (seat). A low-pressure port 16 communicating with a tapered low-pressure passage hole 54 whose passage cross-sectional area gradually increases toward the downstream side in the fuel flow direction is formed on the back side of the low-pressure seat surface 15.
A high pressure sheet surface 17 having the same shape as that of the fourth embodiment is formed on the upper end surface of the orifice plate 10 in the figure. A high-pressure port 18 is formed at the center of the high-pressure sheet surface 17 as in the fourth embodiment.
The control valve 11 of the control valve includes a low pressure side valve portion 71, a high pressure side valve portion 72, a flange portion 74, a valve shaft portion 75, and the like.
The low pressure side valve portion 71 has a low pressure seal surface having the same shape as that of the fourth embodiment.
The high-pressure side valve portion 72 has a high-pressure seal surface having the same shape as that of the fourth embodiment.

Further, the injector is integrated with the valve piston 22 as a displacement transmission member that transmits the displacement of the valve piston 22 to the control valve 11 and switches the control valve 11 from the low pressure seat (state) side to the high pressure seat (state) side. The displacement transmission pin 81 is provided.
The displacement transmission pin 81 includes a cylindrical shaft having a smaller outer diameter than the piston shaft (large-diameter shaft) and the flange 66 of the valve piston 22 and a cylinder having a smaller outer diameter than the medium-diameter shaft. A small-diameter shaft portion having a shape, and a frustoconical connecting portion provided between the medium-diameter shaft portion and the small-diameter shaft portion.
The connecting portion is a reduced diameter shaft portion (tapered shaft portion) that connects the medium diameter shaft portion and the small diameter shaft portion and gradually decreases in outer diameter from the medium diameter shaft portion toward the small diameter shaft portion.
The displacement transmission pin 81 is provided in the low pressure passage hole 54 in the shape of a truncated cone that communicates the low pressure port 16 of the control valve chamber 13 of the valve body 9 and the low pressure port 16 and the spring housing chamber 55 that houses the valve piston spring 24. Are accommodated so as to be reciprocally movable.

In the case of the injector of the present embodiment, the low pressure passage hole 54 of the low pressure fuel passage has the same function as in the first to fourth embodiments (inside the pressure control chamber 14), although it has a simple shape compared to the first to fourth embodiments. A fuel discharge function for allowing the introduced high-pressure fuel to flow out to the low-pressure side of the fuel system through the common flow path hole 45, the control valve chamber 13, and the low-pressure fuel passage can be achieved, so that the cost of the injector can be reduced. be able to.
As described above, the injector of the present embodiment has the same effects as those of the first to fourth embodiments.
Note that the structure of the valve piston 22 and the structure of the fuel outflow passage of this embodiment may be incorporated in the first to fourth embodiments.

[Configuration of Example 6]
FIGS. 10 to 12 (a) show a piezo injector (Embodiment 6) to which the fuel injection valve of the present invention is applied.
Here, the same reference numerals as in the first to fifth embodiments indicate the same configuration or function, and a description thereof will be omitted.

By the way, as shown in Patent Document 1, the injector of the conventional example opens the valve so that the fuel flows out from the control chamber to the low pressure side of the fuel system through the low pressure chamber, and the fuel pressure in the control chamber is reduced. A control valve for lowering is provided.
In the conventional injector, the control chamber and the low pressure chamber communicate with each other through the out orifice on the downstream side of the fuel flow direction from the control valve. In the communication passage that allows fuel to flow out to the low-pressure chamber via the orifice, the flow path cross-sectional area (opening area) changes suddenly (rapidly shrinks) and the fuel flow direction changes suddenly (bents at right angles). Erosion generation due to flow rate variation, fuel flow velocity change (increase), and bubble formation / disintegration is a problem.
Further, when the injection pressure of fuel injected into the cylinder of the engine is increased, the concern about erosion increases, and the drive load of the control valve, that is, the drive load of the actuator increases. There was a problem that accuracy and controllability deteriorated.

Therefore, it is desirable to reduce the valve seat diameter that receives the fuel pressure (oil pressure) flowing out from the control chamber to the low pressure chamber and to reduce the driving load of the actuator.
However, in the conventional injector, in order to form the communication path, it is necessary to provide a relief diameter for communicating with the lower end of the valve body that houses the control valve.
Further, reducing the valve seat diameter is accompanied by a reduction in the relief diameter and the outer diameter of the sliding pin member. As a result, there is a problem that deformation loss due to the driving force of the sliding pin member increases and the driving load of the actuator cannot be reduced as expected.
In addition, in order to form the out orifice, a certain height is required for the relief diameter portion, and in order to secure a necessary sliding length, the entire length of the sliding pin member becomes long, which is also slid. The deformation loss of the moving pin member itself cannot be reduced.

The injector of the present embodiment includes a control valve similar to that of the fourth and fifth embodiments.
The control valve 11 of the control valve includes a low pressure side valve portion 71, a high pressure side valve portion 72, a flange portion 74, a valve shaft portion 75, and the like.
The low pressure side valve portion 71 has a low pressure sealing surface having the same shape as in the fourth and fifth embodiments.
The high-pressure side valve portion 72 has a high-pressure seal surface having the same shape as in the fourth and fifth embodiments.
The injector of this embodiment includes a valve body 9 and an orifice plate 10 that are sandwiched between the contact surface of the nozzle body 2 and the contact surface of the injector body 4.

On the wall surface of the valve body 9, a low-pressure seat surface 15 having the same shape as in the fourth and fifth embodiments is formed. A low pressure port 16 that directly communicates with the spring accommodating chamber 55 of the low pressure fuel passage is formed on the back side of the low pressure seat surface 15.
In addition, a high-pressure sheet surface 17 having the same shape as in Examples 4 and 5 is formed on the upper end surface of the orifice plate 10 in the figure. A high-pressure port 18 is formed at the center of the high-pressure sheet surface 17 as in the fourth and fifth embodiments.

The low pressure fuel passage includes a spring accommodating chamber 55 that communicates with the low pressure port 16, a plurality of radial communication holes 56 that communicate with the spring accommodating chamber 55, and a low pressure passage that communicates these radial communication holes 56 and the outlet port. 57 etc.
The spring accommodating chamber 55 is a low pressure chamber communicating with the control valve chamber 13 via the low pressure port 16. The spring accommodating chamber 55 accommodates the lower end portion (the portion including the flange portion 66) of the valve piston 22 and the valve piston spring 24 so as to be reciprocally movable.
Details of the low pressure port 16 will be described later.

Further, the injector is integrated with the valve piston 22 as a displacement transmission member that transmits the displacement of the valve piston 22 to the control valve 11 and switches the control valve 11 from the low pressure seat (state) side to the high pressure seat (state) side. The displacement transmission pin 65 is provided.
The displacement transmission pin 65 corresponds to a “pin-shaped transmission member” in the claims, and is formed of a highly rigid material having a Young's modulus higher than a predetermined value. The displacement transmission pin 65 has a large-diameter shaft portion 82 that receives a driving force from the actuator 3, a small-diameter shaft portion 83 that has a smaller outer diameter than the large-diameter shaft portion 82 and transmits the driving force to the control valve 11, and a large-diameter shaft. An annular step 84 provided between the portion 82 and the small diameter shaft portion 83 is provided.
The displacement transmission pin 65 is housed in a reciprocating manner in the control valve chamber 13 of the valve body 9 and in the low pressure port 16 that communicates the control valve chamber 13 and the spring housing chamber 55. The step 84 provided on the outer periphery of the displacement transmission pin 65 is compared to the opening of the low pressure seat surface 15 for the purpose of suppressing the flow rate variation of the fuel flowing through the low pressure seat surface (valve seat) 15 of the control valve. Thus, it is set to be a flow path restriction (second out orifice).

  The low-pressure port 16 of this embodiment has a housing hole 91 that houses the displacement transmission pin 65 so as to be able to reciprocate, and a communication portion (hereinafter referred to as a communication passage) 92 that communicates the control valve chamber 13 and the spring housing chamber 55. Yes. The communication path 92 is formed between the hole wall surface of the accommodating hole 91 of the valve body 9 and the outer peripheral surfaces of the large diameter shaft portion 82 and the small diameter shaft portion 83 of the displacement transmission pin 65. In addition, on the upstream side of the communication path 92, a throttle portion 93 that restricts the cross-sectional area of the communication path 92 is provided. The narrowed portion 93 is a small-diameter hole having the smallest channel cross-sectional area in the accommodation hole 91, and is formed between the hole wall surface of the small-diameter hole of the accommodation hole 91 and the outer peripheral surface of the small-diameter shaft portion 83.

As shown in FIG. 12A, the housing hole 91 includes a plurality of sliding wall surfaces 94 that support the sliding portion 86 of the displacement transmission pin 65 so as to be able to reciprocate, and radially outward from the sliding wall surface 94. A plurality of recesses (hereinafter referred to as axial recesses) 95 that are recessed toward the surface.
The plurality of axial grooves 95 have a partial circular shape in cross section perpendicular to the axial direction (fuel flow direction) of the accommodation hole 91.
The low pressure port 16 is formed between the bottom surfaces of the plurality of axial grooves 95 and the outer peripheral surfaces of the large diameter shaft portion 82 and the small diameter shaft portion 83.
The sliding portion 86 of the displacement transmission pin 65 is provided with a plurality of sliding surfaces that reciprocally slide on the plurality of sliding wall surfaces 94.
The plurality of axial concave grooves 95 and the plurality of sliding wall surfaces 94 are provided at predetermined intervals (for example, 120 ° intervals) in the circumferential direction and extend straight in the extending direction of the accommodation hole 91. The plurality of sliding surfaces are provided at predetermined intervals (for example, 120 ° intervals) in the outer peripheral direction of the displacement transmission pin 65 and extend straight in the reciprocating direction of the displacement transmission pin 65.

As described above, the injector of the present embodiment has the same effects as those of the first to fifth embodiments.
In addition, in the injector of the present embodiment, as shown in FIGS. 11 and 12A, the small diameter shaft portion 83 is provided below the large diameter shaft portion 82 of the displacement transmission pin 65 so that the displacement is reduced. The outer diameter of the lower end portion of the transmission pin 65 shown in the figure is released from the hole wall surface of the throttle portion 93. In the injector, fuel flows out from the control valve chamber 13 to the low pressure side of the fuel system by communicating the control valve chamber 13 and the spring accommodating chamber 55 via a plurality of communication passages 92 constituting the low pressure port 16. A communication part to the low-pressure fuel passage is configured.

Such a structure eliminates the need for a relief diameter at the lower end of the low pressure port 16 adjacent to the low pressure seat surface (valve seat) 15 of the control valve. As a result, the valve seat diameter of the low-pressure seat surface 15 that receives fuel pressure (oil pressure) flowing out from the control valve chamber 13 to the low-pressure side of the fuel system via the low-pressure port 16 is reduced, and the driving load of the actuator 3 is reduced. It becomes possible to do. Further, there is no sudden change in the flow direction of the fuel via the plurality of communication passages 92 provided around the displacement transmission pin 65 (and there is no flow passage restriction when the restriction portion 93 is not provided), and the high pressure fuel is reduced in pressure. The structure is such that it can be discharged to the spring accommodating chamber 55 via the port 16. As a result, the occurrence of cavitation erosion (erosion) can be suppressed.
At the same time, as shown in FIG. 11B, the fuel flowing out from the control valve chamber 13 flows into the spring accommodating chamber 55 via the low pressure port 16 that extends straight in the vertical direction in the figure. Compared to conventional injectors, the fuel flow is improved. Thereby, the diameter difference of the lower end part (small diameter shaft part 83) of the displacement transmission pin 65 with respect to the valve seat diameter of the low pressure seat surface 15 can be reduced. As a result, the sliding diameter of the displacement transmission pin 65 can be increased and the driving load of the actuator 3 can be reduced.

On the other hand, the height of the fuel communication step 84 provided on the outer periphery of the displacement transmission pin 65 can be reduced as compared with the conventional injector structure in which the relief diameter on the valve body 9 side and the out orifice exist. As a result, the entire length of the displacement transmission pin 65 can be shortened while maintaining a predetermined sliding length with respect to the sliding wall surface 94 of the valve body 9, and deformation loss due to the driving force of the displacement transmission pin 65 can be further reduced. Can be reduced.
Therefore, the structure in which the communication path 92 is formed around the displacement transmission pin 65 makes it possible to reduce both the valve seat diameter and the deformation loss of the displacement transmission pin 65 itself, and to reduce the driving load of the actuator 3. Can be reduced.
Further, by setting the lower end diameter of the valve body 9 (inner diameter of the throttle portion 93) = the sliding diameter of the displacement transmission pin 65, it is possible to ensure the coaxiality of the sliding wall surface 94 and the small diameter shaft portion (relief portion) 83. it can. As a result, it is advantageous in manufacturing an injector adopting a configuration in which the displacement transmission pin 65 penetrates the low pressure port 16 communicating with the control valve chamber 13 and the spring accommodating chamber 55 so as to be reciprocally slidable. That is, the injector having the above structure can be easily manufactured.
In the communication path 92, it is not necessary to provide the throttle part (flow path throttle) 93 that reduces the cross-sectional area of the communication path 92.

[Configuration of Example 7]
FIGS. 12B and 13 show a piezo injector (Embodiment 7) to which the fuel injection valve of the present invention is applied.
Here, the same reference numerals as those in the first to sixth embodiments indicate the same configuration or function, and a description thereof will be omitted.

The low pressure port 16 of the present embodiment has an accommodation hole 91 and a communication path 92.
As shown in FIG. 12B, the accommodation hole 91 has a plurality of sliding wall surfaces 94 that support the sliding portion 86 of the displacement transmission pin 65 so as to be capable of reciprocating.
The large-diameter shaft portion 82 of the displacement transmission pin 65 is provided with a plurality of concave portions (hereinafter referred to as planing portions) 96 that are recessed from the respective sliding surfaces of the sliding portion 86 toward the inside in the radial direction.
The low pressure port 16 is formed between the hole wall surfaces of the plurality of sliding wall surfaces 94 and the bottom surfaces of the plurality of planing portions 96.
The plurality of planing portions 96 are provided at a predetermined interval (for example, 120 ° interval) in the outer peripheral direction of the displacement transmission pin 65 and extend straight in the reciprocating direction of the displacement transmission pin 65.

In the injector of this embodiment, instead of providing the small diameter shaft portion (relief portion) 83 of the displacement transmission pin 65 and the axial concave groove 95 on the valve body 9 side (see FIG. 12A), the entire length of the displacement transmission pin 65 is provided. The above-described embodiment can also be provided by providing a large-diameter shaft portion 82 over the entire surface, and by cutting (cutting) the outer peripheral surface of the large-diameter shaft portion 82 to provide a plurality of planing portions 96 (see FIG. The effect described in 6 can be achieved.
In the case of this injector, the low pressure port 16 can be a simple straight through hole (accommodating hole 91) without providing the axial concave groove 95 on the valve body 9 side, which is advantageous in manufacturing the valve body.
Note that the low pressure port 16 has only a communication path 92 that allows the control valve chamber 13 and the spring accommodating chamber 55 to communicate with each other. The communication path 92 is formed between the hole wall surface of the accommodating hole 91 of the valve body 9 and the outer peripheral surface of the large-diameter shaft portion 82 of the displacement transmission pin 65.
As described above, the injector of the present embodiment has the same effects as those of the first to sixth embodiments.

[Configuration of Example 8]
FIG. 14 shows a piezo injector (Embodiment 8) to which the fuel injection valve of the present invention is applied.
Here, the same reference numerals as in the first to seventh embodiments indicate the same configuration or function, and the description thereof is omitted.

The injector according to the present embodiment transmits the displacement of the valve piston 22 to the control valve 11 as a displacement transmission member for switching the control valve 11 from the low pressure seat (state) side to the high pressure seat (state) side. An integrated displacement transmission pin 65 is provided.
The displacement transmission pin 65 has a large-diameter shaft portion 82 that receives a driving force from the actuator 3, a small-diameter shaft portion 83 that has a smaller outer diameter than the large-diameter shaft portion 82 and transmits the driving force to the control valve 11, and a large-diameter shaft. A connecting portion 85 having a truncated cone shape provided between the portion 82 and the small diameter shaft portion 83 is provided. The connecting portion 85 is a reduced-diameter shaft (taper shaft portion) that connects the large-diameter shaft portion 82 and the small-diameter shaft portion 83 and gradually decreases in outer diameter from the large-diameter shaft portion 82 toward the small-diameter shaft portion 83. .

The low-pressure port 16 of this embodiment has a housing hole 91 that houses the displacement transmission pin 65 so as to be able to reciprocate, and a communication portion (hereinafter referred to as a communication passage) 92 that communicates the control valve chamber 13 and the spring housing chamber 55. Yes. The communication path 92 is formed between the hole wall surface of the housing hole 91 of the valve body 9 and the outer peripheral surface of the large diameter shaft portion 82, the small diameter shaft portion 83 and the conical surface of the connecting portion 85. Yes.
The accommodation hole 91 includes a small-diameter hole provided on the upstream side (control valve chamber 13 side) of the low-pressure port 16, a large-diameter hole provided on the downstream side of the low-pressure port 16 (spring storage chamber 55 side), and a small-diameter hole. It has a frustoconical diameter expansion hole provided between the large diameter hole.
The large-diameter hole of the accommodation hole 91 is provided with a plurality of sliding wall surfaces 94 that support the large-diameter shaft portion 82 of the displacement transmission pin 65 so as to be slidable back and forth.
The large-diameter shaft portion 82 of the displacement transmission pin 65 has a plurality of sliding surfaces that reciprocally slide on the plurality of sliding wall surfaces 94, and are recessed inward in the radial direction from the sliding portions 86. A plurality of recesses (hereinafter referred to as planar cutting portions) 96 extending in the reciprocating direction of 65 are provided.

The low pressure port 16 is formed between the plurality of sliding wall surfaces 94 and the bottom surfaces of the plurality of planing portions 96.
The plurality of planing portions 96 are provided at a predetermined interval (for example, 120 ° interval) in the outer peripheral direction of the displacement transmission pin 65 and extend straight in the reciprocating direction of the displacement transmission pin 65.
As described above, the injector of the present embodiment has the same effects as those of the first to seventh embodiments.
In addition, in the injector of this embodiment, the deformation loss can be further reduced by adopting a structure in which only the sliding portion 86 having a plurality of sliding surfaces has an enlarged outer diameter.

[Modification]
In the present embodiment, a control valve that opens and closes (switches) the control plate 6 according to the vertical pressure difference is employed as the on-off valve of the present invention. However, the control plate 6 is opened and closed as the on-off valve of the present invention. An actuator to be operated may be provided, and the opening / closing valve may be opened / closed by a driving force of the actuator according to a switching command from an engine control unit (electronic control unit: ECU) at a predetermined switching timing.

  In the present embodiment, a piezo-stacked body that expands and contracts in the axial direction by charge and discharge is assumed as the actuator 3 that opens and drives the control valve 11 that is a valve body of a control valve that controls increase and decrease of the fuel pressure in the pressure control chamber 14. However, an actuator that uses a solenoid actuator, an electric actuator, a magnetostrictive element, or the like as a drive source may be used as the actuator that opens or closes the valve body of the control valve.

In this embodiment, as the fuel injection valve of the present invention, a fuel injection valve (injector) of a type in which a plurality of injection holes 27 are opened and closed by the needle 1 accommodated in the nozzle body 2 so as to be able to reciprocate is adopted. As a fuel injection valve of the present invention, a variable injection hole type fuel injection in which a plurality of first and second injection holes are opened and closed in stages by two first and second needles accommodated in a nozzle body 2 so as to be reciprocally movable. A valve (injector) may be employed.
Further, as the internal combustion engine (engine), a gasoline engine may be used instead of the diesel engine.

Further, the fuel supply path for supplying the fuel stored in the fuel tank to the fuel injection valve (injector) of the internal combustion engine via the supply pump is the fuel supply upstream of the pressurizing chamber of the supply pump. Refers to the route.
The fuel injection valve of the present invention may be applied to a fuel injector that injects fuel into a cylinder of an internal combustion engine (engine) such as a gasoline engine or an intake port communicating with the cylinder.

In this embodiment, the displacement transmission pin 65 having a separate structure is used as the pin-shaped transmission member with respect to the control valve 11 and the valve piston 22, but the control valve 11 or the valve piston is used as the pin-shaped transmission member. Alternatively, a displacement transmission pin 65 that is integral with either one of the two members 22 may be used.
In any of the embodiments, the material of the pin-shaped transmission member (displacement transmission pin 65) is a high-rigidity material (eg, super steel, ceramics) having a Young's modulus higher than a predetermined value (eg, 200 GPa) such as super steel. Etc.), deformation loss can be reduced without changing the physique of the pin-shaped transmission member.

1 Needle 3 Actuator 6 Control plate (open / close valve)
11 Control valve (valve of control valve)
12 Valve spring (elastic member of control valve)
13 Control valve chamber 14 Pressure control chamber 38 In-orifice hole (second in-orifice, main-in orifice)
43 In-orifice hole (first in-orifice, sub-in-orifice)
52 Out orifice hole (Main out orifice)

Claims (16)

(A) a needle (1) for opening and closing a nozzle hole (27) for injecting fuel into a cylinder of the internal combustion engine;
(B) a control chamber (14) for storing fuel pressure acting in a valve closing direction on the needle (1);
(C) a communication port (19) that is always in communication with the control chamber (14), a high-pressure fuel passage (31-34, 37, 38, 41-43) through which high-pressure fuel introduced into the control chamber (14) flows. A control valve chamber (13) having a high pressure port (18) in communication and a low pressure port (16) in communication with a low pressure fuel passage (53-57) for letting fuel flow out from the control chamber (14) to the low pressure side of the fuel system. When,
(D) A valve body (11) which is accommodated in the control valve chamber (13) and selectively switches between communication and blocking between the high pressure port (18) or the low pressure port (16) and the communication port (19). And a control valve having
(E) The valve body (11) of the control valve communicates the high pressure port (18) and the communication port (19), and blocks communication between the low pressure port (16) and the communication port (19). The low-pressure seal state is switched to the high-pressure seal state in which the low-pressure port (16) and the communication port (19) are communicated and the high-pressure port (18) and the communication port (19) are disconnected. An actuator (3) for generating a driving force,
In the fuel injection valve that controls the opening / closing operation of the needle (1) by adjusting the fuel pressure in the control chamber (14) by switching the valve body (11) of the control valve.
The high-pressure fuel passages (31-34, 37, 38, 41-43) regulate at least two first and second in-orifices (38, 43) that regulate the flow rate of fuel introduced into the control chamber (14). )
The fuel injection valve supplies high-pressure fuel from the first in-orifice (43) to the control chamber (14) via the high-pressure port (18), the control valve chamber (13), and the communication port (19). A first introduction path (43, 18, 13, 44, 45, 48, 49) to be introduced;
A second introduction path for introducing high pressure fuel from the second in orifice (38) to the control chamber (14) by bypassing the high pressure port (18), the control valve chamber (13) and the communication port (19). (37, 38, 48, 49),
On-off valve (6) displaceable in two positions: a fully open position for opening the second introduction path (37, 38, 48, 49) and a fully closed position for closing the second introduction path (37, 38, 48, 49). 7). A fuel injection valve comprising: The fuel injection valve according to claim 1, wherein
The fuel injection valve is characterized in that the passage flow rate of the second in-orifice (38) is set larger than the passage flow rate of the first in-orifice (43). The fuel injection valve according to claim 1, wherein
The fuel injection valve is characterized in that the passage flow rate of the second in-orifice (38) is set smaller than the passage flow rate of the first in-orifice (43). In the fuel injection valve according to any one of claims 1 to 3,
The on-off valve has a pressure-actuated control plate (6) for opening and closing a flow path communicating the second in-orifice (38) and the control chamber (14). valve. In the fuel injection valve according to any one of claims 1 to 4,
The fuel injection valve includes an out orifice (52, 53) for regulating a flow rate of fuel flowing out from the control chamber (14) to the low pressure fuel passage (53-57) through the control valve chamber (13). The fuel injection valve characterized by the above-mentioned. The fuel injection valve according to claim 5,
The fuel injection valve is characterized in that the throttle diameter is set so that the first in-orifice (43) is larger than the flow rate through the out-orifice (52, 53). . The fuel injection valve according to claim 5 or 6,
The out-orifice is a first out-orifice (52) installed upstream of the control valve chamber (13) in the fuel flow direction, and downstream of the control valve chamber (13) in the fuel flow direction. A fuel injection valve characterized by having a second out orifice (53) installed in the cylinder. The fuel injection valve according to claim 7,
The fuel injection valve is characterized in that the throttle diameter is set so that the passage flow rate of the second out orifice (53) is larger than the passage flow rate of the first out orifice (52). Fuel injection valve. The fuel injection valve according to any one of claims 1 to 8,
The fuel injection valve according to claim 1, wherein the control valve includes an elastic member (12) that urges the valve body (11) to a side for switching from the high-pressure seal state to the low-pressure seal state. The fuel injection valve according to any one of claims 1 to 9,
The actuator (3) has a piezo element laminate that expands and contracts due to charge and discharge of electric charge. The fuel injection valve according to any one of claims 1 to 10,
The fuel injection valve transmits a driving force of the actuator (3) to the valve body (11), and at the same time, a pin-shaped transmission member (65 capable of reciprocating in the switching operation direction of the valve body (11) of the control valve. )
The low pressure fuel passage has a low pressure chamber (55) communicating with the control valve chamber (13) via the low pressure port (16),
The control valve has a valve body (9) that accommodates the valve body (11) so as to be capable of opening and closing, and forms the control valve chamber (13) and the low-pressure port (16),
The low-pressure port (16) includes an accommodation hole (91) that accommodates the transmission member (65) so as to be capable of reciprocating movement, and a hole wall surface of the accommodation hole (91) and an outer peripheral surface of the transmission member (65). The fuel injection valve is characterized in that it has communication portions (92, 93) that communicate with the control valve chamber (13) and the low pressure chamber (55). The fuel injection valve according to claim 11, wherein
The fuel injection valve, wherein the transmission member (65) is made of a highly rigid material having a Young's modulus higher than a predetermined value. The fuel injection valve according to claim 11 or 12,
The transmission member (65) has a large-diameter shaft portion (82) that receives a driving force from the actuator (3), and has an outer diameter smaller than that of the large-diameter shaft portion (82). A small-diameter shaft portion (83) for transmitting the fuel, and an annular step (84) provided between the large-diameter shaft portion (82) and the small-diameter shaft portion (83). valve. The fuel injection valve according to any one of claims 11 to 13, wherein
The communication part has a communication path (92) for communicating the control valve chamber (13) and the low pressure chamber (55),
The fuel injection valve, wherein the communication passage (92) has a throttle portion (93) for restricting the cross-sectional area of the flow passage. The fuel injection valve according to any one of claims 11 to 14,
The accommodation hole (91) is a sliding wall surface (94) that supports the sliding portion (86) of the transmission member (65) so as to be reciprocally slidable, and radially outward from the sliding wall surface (94). A recess (95) extending in the reciprocating direction of the transmission member (65),
The fuel injection valve, wherein the low pressure port (16) is formed between an outer peripheral surface of the transmission member (65) and a bottom surface of the recess (95). The fuel injection valve according to any one of claims 11 to 15,
The accommodation hole (91) has a sliding wall surface (94) that supports the sliding portion (86) of the transmission member (65) so as to be slidable back and forth.
The transmission member (65) is recessed radially inward from the sliding portion (86), and has a recess (96) extending in the reciprocating direction of the transmission member (65).
The fuel injection valve, wherein the low pressure port (16) is formed between a hole wall surface of the accommodation hole (91) or the sliding wall surface (94) and a bottom surface of the recess (96).

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