JP4650395B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve for an automobile internal combustion engine, and more particularly to a fuel injection valve that controls opening and closing of a nozzle needle using an electromagnetic control valve.

As a common rail fuel injection valve for diesel engines, fuel injection has been achieved by supplying high pressure fuel from the common rail to the nozzle chamber of the injection nozzle and increasing or decreasing the back pressure of the nozzle needle using an electromagnetic control valve. And a stop (for example, patent document 1 etc.). The electromagnetic control valve switches the communication between the valve chamber in which the valve body integrated with the solenoid is accommodated and the low-pressure fuel discharge passage communicating with the fuel tank or the high-pressure fuel introduction passage communicating with the common rail. By controlling the pressure in the needle back pressure chamber, that is, the seating and separation of the nozzle needle, the fuel injection can be controlled to a high degree.
JP 2004-251205 A

On the other hand, in order to reduce the overall diameter of the device by reducing the solenoid diameter, the present inventors have proposed a device for controlling the pressure in the nozzle needle back pressure chamber by providing another control valve driven by an electromagnetic control valve. (Patent Document 2 or Japanese Patent Application No. 2006-198007). In this device, a pressure control chamber into which high pressure fuel from the common rail is introduced is provided, and when the electromagnetic control valve opens and closes between the pressure control chamber and the low pressure fuel discharge flow path, the back pressure of the other control valve increases and decreases, The nozzle needle back pressure chamber and the low pressure fuel discharge passage are configured to open and close.
JP 2006-257874 A

  When the diameter of the solenoid of the electromagnetic control valve is reduced, the attraction force is also reduced due to the reduction in the magnetic pole area due to the reduction in diameter. Therefore, it is necessary to reduce the fuel pressure in the lift direction acting on the valve body. In this configuration, since the responsiveness of the nozzle needle depends on the fuel outflow speed of the nozzle needle back pressure chamber controlled by another control valve, the fuel pressure acting on the valve body of the electromagnetic control valve is reduced. Even if the sheet diameter is reduced, there is an advantage that the response of the nozzle needle is not affected.

  However, if the solenoid is made small, the spring force for urging the valve body in the valve closing direction is set small. In this case, the operation of the valve body and armature of the electromagnetic control valve is likely to be affected by the pressure fluctuation of the low pressure discharge flow path associated with the on-off valve, and there is a possibility that the injection amount varies. As a countermeasure, for example, in Patent Document 2, a check valve is provided at the inlet of the armature chamber to suppress the pressure fluctuation due to the fuel flowing out from the pressure control chamber or the nozzle needle back pressure chamber from propagating to the armature chamber. An example is shown.

  Further, in the armature chamber, when the air in the fuel is degassed with the operation of the armature and bubbles are generated and stay in the upper portion of the armature chamber, the behavior of the electromagnetic control valve may become unstable. For this reason, in Japanese Patent Application No. 2006-198007, the pressure of the low pressure system is slightly increased (for example, about 0.2 MPa) so that the armature chamber has a negative pressure so that the air is not degassed. It is carried out.

  However, the check valve of Patent Document 2 is very small and has a complicated configuration, and an increase in cost is inevitable. Further, in the configuration of Japanese Patent Application No. 2006-198007, the generation of bubbles is suppressed by increasing the pressure of the low pressure system, but the armature operation tends to be delayed as compared with the prior art. For this reason, when it is required to open and close the electromagnetic control valve at a high speed as in the fine injection amount control, the controllability may be deteriorated.

  The present invention has been made in view of this situation, and by suppressing the pressure fluctuation generated in the low-pressure system, stabilizing the operation of the electromagnetic control valve, and improving the responsiveness by opening and closing the valve at high speed, In addition, a fuel injection valve having excellent injection amount controllability is realized.

3. The fuel injection valve according to claim 1, wherein the fuel injection valve is an electromagnetic control valve that controls communication between a pressure control chamber to which high-pressure fuel is supplied from a high-pressure fuel introduction passage, and communication between the pressure control chamber and the low-pressure fuel discharge passage. And a nozzle portion for opening and closing the nozzle hole and injecting high-pressure fuel supplied from the high-pressure fuel introduction flow path, and when the electromagnetic control valve is operated to increase or decrease the pressure in the pressure control chamber, the nozzle The needle moves up and down.
The electromagnetic control valve has an armature that is suction-driven by a drive body, and a valve body that is integral with the armature. The valve chamber in which the valve body is housed and the armature chamber in which the armature is housed have a low-pressure fuel discharge flow. Connected to the road. Further, in the middle of the low-pressure flow path or low-pressure fuel discharge flow path downstream from the armature chamber, it is arranged so as to come into contact with the fuel flowing through the low-pressure flow path or low-pressure fuel discharge flow path, and the compression elasticity that changes the volume by the fuel pressure An elastic body accommodating chamber for accommodating the body is provided.
The elastic body accommodating chamber accommodates the compression elastic body in a space formed between the outer peripheral side surface of the driving body and the body member at a position directly above the armature chamber,
The fuel in the armature chamber is discharged to the low pressure fuel discharge path through the low pressure passage formed in contact with the bottom surface of the compression elastic body.
The space serving as the elastic body accommodation chamber is provided on the outer periphery on the lower end side of the drive body, and the body member on the outer periphery on the upper end side of the drive body can be in contact with the outer peripheral side surface on the upper end side of the drive body to transfer heat. The support part to hold | maintain was provided.

In the above configuration, when the valve body of the electromagnetic control valve is opened, fuel flows out from the pressure control chamber and is discharged to the low pressure fuel discharge passage. Although the pressure in the valve chamber and the armature chamber fluctuates due to the spilled fuel, the pressure elastic body accommodated in the elastic body accommodating chamber contacts the fuel and changes the volume according to the pressure. As a result, pressure fluctuations in the low-pressure system can be suppressed, so that the behavior of the valve body and the armature is stabilized. Therefore, it is not necessary to provide a check valve or increase the pressure of the low pressure system, and it is possible to realize a fuel injection valve having a small and simple structure and excellent in injection amount controllability.
Specifically, when the elastic body accommodating chamber is formed immediately above the armature chamber, the fuel discharged from the armature chamber to the low pressure fuel flow path and the compression elastic body are brought into contact with each other, thereby obtaining an effect of suppressing pressure fluctuation. Cheap. In addition, the degassing gas from the fuel moving upward from the armature chamber can be easily collected, and the temperature drop of the compression elastic body can be suppressed by heat transfer from the drive body, so that the gas state is stable and the damper by the compression elastic body The effect can be exhibited efficiently.
If the elastic body accommodating chamber completely surrounds the drive body, there is a possibility that heat radiation from the drive body will be insufficient. Therefore, the elastic body accommodating chamber is provided only on the outer periphery on the lower end side of the driving body, and the upper end side of the driving body is brought into close contact with a support portion capable of transferring heat to the base side, thereby improving heat dissipation. As described above, by appropriately disposing the elastic body accommodating chamber and the support portion in the axial direction adjacent to the driving body, it is possible to achieve both heat transfer to the compression elastic body and heat radiation of the driving body.

  According to a second aspect of the present invention, the compression elastic body is a gas body separated from the fuel component.

  When the high-pressure fuel flows out from the pressure control chamber, the pressure of the high-pressure fuel is abruptly reduced, and the air or the like dissolved in the fuel component is gasified and moved upward. By collecting this gas as a compression elastic body in a space provided downstream of the armature chamber, an elastic body accommodating chamber can be formed.

According to a third aspect of the present invention, the armature chamber is disposed immediately above the valve chamber, and a low-pressure flow path is provided that communicates the top surface of the valve chamber and the bottom surface of the armature chamber.

  Preferably, when the armature chamber is directly above the valve chamber, the degassing gas generated in the valve chamber moves upward, and easily flows into the armature chamber from the low-pressure flow path that connects both chambers. The gas body that becomes the compression elastic body can be efficiently stored in the elastic body storage chamber.

In invention of Claim 4 ,
A pressure control chamber to which high-pressure fuel is supplied from the high-pressure fuel introduction channel;
An electromagnetic control valve that controls communication and blocking between the pressure control chamber and the low-pressure fuel discharge passage;
A nozzle needle that opens and closes an injection hole to inject high-pressure fuel supplied from the high-pressure fuel introduction flow path,
A fuel injection valve that drives the nozzle unit by increasing or decreasing the pressure in the pressure control chamber in accordance with the operation of the electromagnetic control valve,
The electromagnetic control valve has an armature that is suction-driven by a driving body, and a valve body that is integral with the armature.
The valve chamber in which the valve body is accommodated and the armature chamber in which the armature is accommodated are communicated with the low pressure fuel discharge flow path through a low pressure flow path, and the low pressure flow path or the low pressure fuel discharge flow downstream from the armature chamber. In the middle of the path, an elastic body accommodating chamber is provided that accommodates a compression elastic body that is disposed so as to be in contact with the fuel that flows through the low-pressure flow path or the low-pressure fuel discharge flow path and changes the volume by the fuel pressure.
The compression elastic body is a gas body separated from the fuel component,
The low-pressure fuel discharge passage is arranged on the side of the electromagnetic control valve to connect the armature chamber and the valve chamber, and is formed by branching upward from the low-pressure fuel discharge passage at a position above the armature chamber. The above-mentioned compression elastic body was accommodated in the space part which was made, and it was set as the above-mentioned elastic body accommodation room.

According to a fifth aspect of the present invention, the compression elastic body is a gas body filled in a deformable storage bag.

In the invention according to claim 6 , the storage bag is divided into a plurality of bags, and each of the divided bags is filled with the compression elastic body.

In the invention of claim 7, a hydraulic switching valve that operates by the pressure of the pressure control chamber;
A nozzle needle back pressure chamber for generating a back pressure of the nozzle needle when high pressure fuel is supplied from the high pressure fuel introduction flow path;
As the electromagnetic control valve increases or decreases the pressure in the pressure control chamber, the hydraulic switching valve is configured to switch communication and blocking between the nozzle needle back pressure chamber and the low pressure fuel discharge passage.

  If the hydraulic switching valve is provided in addition to the electromagnetic control valve to open and close between the nozzle needle back pressure chamber and the first low pressure chamber, the driving body can be reduced in size. Since the driving force for opening and closing the hydraulic switching valve is obtained by hydraulic pressure, the lift amount of the hydraulic switching valve can be set sufficiently large without depending on the driving force of the driving body. The driving force of the driving body may be sufficient as the driving force for attracting the armature against the spring force and opening and closing between the hydraulic chamber and the second low-pressure chamber. Therefore, it is possible to realize a fuel injection valve that is small and has excellent injection performance.

(First embodiment)
A first embodiment to which the present invention is applied will be described below with reference to FIGS. FIG. 2 is a diagram showing an overall configuration of an injector I which is a fuel injection valve of the present invention, and is applied to, for example, a diesel engine equipped with a common rail type fuel injection system. A fuel that has been pressurized to a high pressure by a high-pressure supply pump is accumulated in a common rail (not shown), and is supplied from the high-pressure fuel introduction port 611 of the injector I to the high-pressure fuel introduction passage 61. The leaked fuel from the injector I is discharged from the low-pressure fuel discharge passage 62 to a fuel tank (not shown). The injectors I are provided in a one-to-one correspondence with the cylinders of the engine, and the fuel supplied by the common rail is controlled by an unillustrated ECU so that the drive is controlled so as to achieve the optimal injection amount and injection timing. Inject.

  As shown in FIG. 2, the injector I includes a nozzle body B1, a distance piece B2, a valve body B3, a holder B4, a valve body B6, and a retaining nut B5 as body members constituting the rod-shaped base B. . The holder B4 that accommodates the nozzle body B1, the distance piece B2, the valve body B3, and the valve body B6 is in contact with the opposing end face and is coupled to each other by a retaining nut B5. Various recesses and holes are formed inside the base B, and each component member is accommodated and a fuel flow path is formed.

  The injector I has a lower end portion in the figure as a nozzle portion 1 protruding into the combustion chamber of the corresponding cylinder. In the nozzle body B1 constituting the nozzle portion 1, a vertical hole 111 is formed in the axial direction of the base body B, and the nozzle needle 11 is accommodated in this. The nozzle needle 11 is slidably held in the cylindrical member 112 at its upper end. The bottom of the vertical hole 111 in the drawing reaches the tip of the nozzle body B1, and the nozzle hole 12 is formed through the chamber wall of the nozzle chamber 13 formed at the tip. The vertical hole 111 communicates with the high-pressure fuel introduction passage 61 formed in the distance piece B2, the valve body B3, and the holder B4 on the lower end side of the sliding portion of the nozzle needle 11.

  The high-pressure fuel introduction passage 61 communicates with the common rail via a high-pressure fuel introduction port 611 that opens at the end surface of the holder B4. When the nozzle needle 11 is separated, the high-pressure fuel introduction passage 61 is supplied to the high-pressure fuel introduction passage 61 from the common rail. Fuel is injected from the injection hole 12.

  A nozzle needle back pressure chamber 5 for generating a back pressure of the nozzle needle 11 is formed at the upper end portion of the vertical hole 111 with the distance piece B2 as an upper wall and the upper end portion of the nozzle needle 11 as a lower wall. Further, a coil spring 14 disposed on the outer periphery of the nozzle needle 11 constantly urges the nozzle needle 11 in the seating direction. Further, the pressure of the fuel from the high-pressure fuel introduction passage 61 is urged to the nozzle needle 11 in the seating direction, and the nozzle when the pressure in the needle back pressure chamber 5 becomes a predetermined valve opening start pressure or less. The needle 11 is separated and fuel is injected, and when the pressure in the needle back pressure chamber 5 becomes equal to or higher than a predetermined valve closing start pressure, the nozzle needle 11 is seated and the fuel injection is stopped.

  The back pressure control unit 2 switches the pressure of the nozzle needle back pressure chamber 5 between high and low. The back pressure control unit 2 includes an electromagnetic control valve 3 that is driven by a solenoid 31 that is a driving body, and a hydraulic switching valve 4. The electromagnetic control valve 3 controls the communication and blocking between the pressure control chamber 21 and the low-pressure fuel discharge passage 62, and drives the hydraulic switching valve 4 by increasing or decreasing the pressure in the pressure control chamber 21. Around the solenoid 31 of the electromagnetic control valve 3, an elastic body accommodating chamber 7 which is a characteristic part of the present invention is formed. The hydraulic switching valve 4 has a three-way valve structure, and selectively communicates the nozzle needle back pressure chamber 5 with the high pressure fuel introduction passage 61 or the low pressure fuel discharge passage 62 to increase or decrease the nozzle needle back pressure. The detailed structure of the back pressure control unit 2 is shown in an enlarged manner in FIG. In FIG. 1, in order to facilitate explanation of each part of the back pressure control unit 2 and the flow path configuration, the cross section is partially different from that in FIG. 2.

  In FIG. 1, the valve body B <b> 3 is formed with a vertical hole 23 that expands at the lower end in the axial direction of the injector I, and a second valve chamber 22 is formed by the expanded diameter portion of the vertical hole 23. The hydraulic switching valve 4 has a constricted portion near the lower end of the rod-like main body 4b, and the upper end side of the constricted portion is a sliding portion and is slidably held in the vertical hole 23. The lower end side of the constricted portion is located in the second valve chamber 22 and is a large-diameter valve body portion 4a. The upper end portion and the lower end portion of the valve body portion 4 a are chamfered in a taper shape, and the size is such that an annular gap is formed between the valve body portion 4 a and the side wall surface of the second valve chamber 22.

  The distance piece B2 sandwiched between the valve body B3 and the needle body B1 and forming the lower wall portion of the second valve chamber 22 is formed with a hole penetrating in the axial direction of the injector I. The chamber 22 and the needle back pressure chamber 5 serve as a communication path 51 that always communicates. An orifice 52 is formed in the communication path 51 in the middle.

  The valve body B3 is formed with a high-pressure branch passage 63 that branches from the high-pressure fuel introduction passage 61 and communicates with the second valve chamber 22. The tip of the high-pressure branch passage 63 opens to the side wall surface of the vertical hole 23 at the position of the constriction portion of the hydraulic switching valve 4 and communicates with the second valve chamber 22 via an annular space on the outer periphery of the constriction portion. When the valve body portion 4a of the hydraulic switching valve 4 is displaced upward, the upper tapered portion of the valve body portion 4a is seated with the step surface of the second valve chamber 22 as the upper seat. At this time, the communication between the second valve chamber 22 and the high-pressure branch passage 63 is blocked.

  On the other hand, the distance piece B2 is formed with a low-pressure branch passage 65 that branches from the low-pressure fuel discharge passage 62 and communicates with the second valve chamber 22. The low-pressure branch passage 65 opens in the lower wall surface of the second valve chamber 22 at a position facing the lower end surface of the valve body 4a of the hydraulic switching valve 4, and the opening end has a second discharge hole 64 having an orifice. It has become. When the valve body part 4a is displaced downward and is seated on the lower seat of the lower wall surface of the second valve chamber 22 to close the second discharge hole 64, the communication between the second valve chamber 22 and the low-pressure branch passage 65 is cut off. Is done.

  The hydraulic switching valve 4 is displaced by increasing or decreasing the pressure in the pressure control chamber 21 formed in the vertical hole 23 above the main body portion 4b. Further, in the main body portion 4b, a vertical hole 41 whose upper end opens into the pressure control chamber 21 and whose lower end reaches the lower end position of the constricted portion, and a horizontal hole 42 that constantly communicates the vertical hole 41 with the annular space on the outer periphery of the constricted portion. Is formed. By means of the vertical holes 41 and the horizontal holes 42, high pressure fuel is supplied to the pressure control chamber 21 from the high pressure fuel introduction passage 61 via the high pressure branch passage 63, and the back pressure of the hydraulic switching valve 4 is generated. It has become. The hydraulic switching valve 4 is always urged downward by the spring force of the coil spring 24 accommodated in the pressure control chamber 21.

  The pressure control chamber 21 communicates with the first valve chamber 34 that is a valve chamber via a communication path 66. The communication path 66 is configured by a small hole that opens from the top of the vertical hole 23 to the upper end surface of the valve body B3 and opens to the lower wall surface of the first valve chamber 34, and the opening end thereof is a first discharge hole 67 having an orifice. It has become. The first valve chamber 34 is formed by a recess formed in the lower end surface of the valve body B3 and the valve body B6 above it. The first valve chamber 34 is always in communication with the low-pressure fuel discharge passage 62 via the low-pressure passage 81 connected to the annular recess on the valve body B3 side.

  The electromagnetic control valve 3 includes an armature 32 that is positioned opposite the solenoid 31, a valve needle 36 that is displaced integrally with the armature 32, and a valve body 35, and communication between the pressure control chamber 21 and the first valve chamber 34 is interrupted. Is switched. The solenoid 31 has a coil wound around an annular space of a double cylindrical stator, and is energized via a lead wire 37 (see FIG. 2) connected to the coil.

  A disk-shaped armature 32 is accommodated in an armature chamber 33 provided facing the lower end of the solenoid 31 and is opposed to the magnetic pole surface of the solenoid 31 with a valve gap d. A coil spring 38 is accommodated in the inner periphery of the solenoid 31 and elastically contacts the armature 32 to urge the armature 32 in a direction away from the solenoid 31. A plurality of through holes 321 are provided in the outer peripheral portion of the armature 32 so that fuel can flow through the upper and lower spaces as the armature 32 moves.

  A vertical hole 39 is formed in the valve body B6 so as to penetrate the upper wall portion of the first valve chamber 34 and reach the bottom surface of the armature chamber 33 positioned immediately above the first valve chamber 34. The valve needle 36 is slid into the vertical hole 39. It is held freely. An upper end portion of the valve needle 36 protrudes into the armature chamber 33 and is fixed to a lower end surface of the armature 32, and a lower end portion of the valve needle 36 protrudes into the first valve chamber 34.

  The lower end portion of the valve needle 36 protruding into the first valve chamber 34 is configured to be displaced integrally while holding a hemispherical valve body 35 in a recessed portion provided on the lower end surface. The flat bottom end surface of the valve body 35 faces the lower wall surface of the first valve chamber 34 at the opening position of the first discharge hole 67. When the valve body 35 is displaced downward and is seated on the seat surface of the outer peripheral edge of the first discharge hole 67, the first discharge hole 67 is closed and the communication between the first valve chamber 34 and the pressure control chamber 21 is blocked. . When the valve body 35 is displaced upward and is separated from the seat surface of the outer peripheral edge portion of the first discharge hole 67 and the first discharge hole 67 is opened, the fuel in the pressure control chamber 21 flows from the first valve chamber 34 to the low pressure flow path 81. And then flows out to the low-pressure fuel discharge passage 62.

  The valve body B6 is formed with a plurality of low-pressure channels 82 communicating with the top surface of the first valve chamber 34 and the bottom surface of the armature chamber 33 on the side of the vertical hole 39 through which the valve needle 36 slides. . As a result, the fuel that flows out when the electromagnetic control valve 3 is opened can flow out from the first valve chamber 34 to the armature chamber 33 via the low-pressure channel 82.

  A space 71 serving as the elastic body accommodating chamber 7 is formed on the side of the armature chamber 33 and the solenoid 31. The space portion 71 includes a clearance between the inner peripheral surface of the holder B4 and the outer peripheral side surface of the lower half portion of the solenoid 31, and a clearance between the annular groove formed on the outer periphery of the upper end portion of the valve body B6. The space 71 communicates with the armature chamber 33 by a low-pressure channel 83 formed by cutting out the upper end of the valve body B6, while the low-pressure channel 84 opens to the inner peripheral surface of the holder B4 facing the bottom side surface of the solenoid 31. Thus, the low pressure fuel discharge passage 62 is communicated. As a result, the armature chamber 33 always communicates with the low-pressure fuel discharge channel 62 via the low-pressure channel 83, the space 71, and the low-pressure channel 84.

  The space 71 above the low-pressure channel 84 serves as an elastic body accommodating chamber 7 for accommodating a gas body separated from the fuel component as the compression elastic body G. The elastic body accommodating chamber 7 is a space where the upper part formed in the gap between the inner peripheral surface of the holder B4 and the outer peripheral side surface of the solenoid 31 is closed, and the volume from the upper closed part to the low pressure channel 84 forming part is elastic. It is defined as the volume of the body accommodating chamber 7. The gas body is a multi-component gas lump that is mainly degassed of air components (nitrogen, oxygen) mixed in the fuel, and also includes gasified components such as moisture and fuel components. These components are gasified and desorbed from the fuel due to a rapid pressure drop accompanying opening of the electromagnetic control valve 3, move upward in the flow path, and accumulate in the elastic body accommodating chamber 7. The elastic body accommodating chamber 7 is always replenished with degassed gas to maintain the compression elastic body G at a predetermined volume, and gas components exceeding the volume of the elastic body accommodating chamber 7 are discharged from the low pressure channel 84 to the low pressure fuel discharge channel. It is discharged to 62.

  The compression elastic body G in the elastic body accommodating chamber 7 is in contact with the fuel flowing through the space 71 below the low pressure channel 84 and has a damper effect that changes the volume according to the pressure. In order to obtain this effect, it is better that the volume of the elastic body accommodating chamber 7 (the volume of the compression elastic body G) is large. Further, since it is provided close to the position above the armature chamber 33 where the gas is generated, the degassed gas tends to accumulate.

  In addition, by disposing the elastic body accommodating chamber 7 on the outer periphery of the solenoid 31, the heat of the solenoid 31 is transmitted to the compression elastic body G of the adjacent elastic body accommodating chamber 7, and the compression elastic body G is maintained at a high temperature. can get. Thereby, it is suppressed that a volume reduces by the temperature fall of the compression elastic body G, and the stable gas state can be maintained.

  At this time, it is desirable to ensure heat dissipation from the solenoid 31 to the base B so that the elastic body accommodating chamber 7 does not completely surround the outer peripheral side surface of the solenoid 31. In this embodiment, the inner peripheral surface of the holder B4 protrudes inward above the elastic body accommodating chamber 7, and is in close contact with the outer peripheral surface of the upper end portion of the solenoid 31 so as to be able to transfer heat and To do. The support part B7 functions as a heat radiator that transmits the heat of the solenoid 31 to the base B side via the holder B4, and suppresses the solenoid 31 from excessively rising in temperature.

  Thus, on the outer peripheral side of the solenoid 31, the elastic body accommodating chamber 7 and the support portion B7 are arranged in a balanced manner in the axial direction, so that heat is dissipated from the solenoid 31 to the base B and heat is transferred to the compression elastic body G. Both effects can be achieved. For example, the amount of heat generated by the solenoid 31 is determined by the drive current, the conductor resistance, and the drive time. In order to dissipate the calorific value from the surface, there are strong factors that depend on its physique. However, in the miniaturized solenoid 31, since the surface area becomes relatively small, the heat dissipation is often given priority over the heat transfer of the elastic body. In this case, it is more preferable that the contact area with the support portion B7 is larger than the contact area with the elastic body accommodating chamber 7.

  FIG. 3A is a block diagram showing a schematic configuration of the injector I of the first embodiment shown in FIGS. 1 and 2. The pressure control chamber 21 and the electromagnetic control valve 3 have a first discharge hole 67 having an orifice. Communicated through. In the electromagnetic control valve 3, the first valve chamber 34 is connected to the low-pressure fuel discharge channel 62 through the low-pressure channel 81, and the armature chamber 33 is connected to the low-pressure fuel discharge channel 62 through the low-pressure channel 83. And the armature chamber 33 communicate with each other through a plurality of low-pressure channels 82 (see FIG. 1).

  The elastic body accommodating chamber 7 of the first embodiment is disposed between the low pressure flow path 83 and the low pressure flow path 84 downstream of the armature chamber 33 located immediately above the first valve chamber 34. The compression elastic body G of the elastic body accommodating chamber 7 contacts the fuel F traveling from the low pressure channel 83 to the low pressure channel 84 and absorbs pressure fluctuation. In this configuration, when the pressure control chamber 21 and the first valve chamber 34 communicate with each other, the gas body (compression elastic body G) generated by deaeration from the discharged fuel moves upward and is positioned above the armature chamber 33. Since there are two discharge paths to the low-pressure fuel discharge passage 62 while being accommodated in the elastic body accommodating chamber 7, the passage area can be secured and fuel can be discharged quickly, and controllability is improved.

  As shown in FIG. 3B as the second embodiment, the discharge path to the low-pressure fuel discharge flow path 62 may be a single system. In this case, it is preferable to omit the low-pressure channel 81 following the first valve chamber 34 and to dispose the elastic body accommodating chamber 7 above the low-pressure channels 83 and 84 on the armature chamber 33 side. An example of this configuration is shown in FIG. FIG. 4 shows a simplified configuration of the main part of the injector I. The overall configuration and the detailed structure of each part are the same as those in the first embodiment, and a description thereof will be omitted.

  In FIG. 4, in the electromagnetic control valve 3 constituting the back pressure control unit 2, the first valve chamber 34 is not directly connected to the low pressure fuel discharge channel 62, and the armature chamber 33 communicates with the plurality of low pressure channels 82. Only through the low pressure fuel discharge passage 62. Above the armature chamber 33, a space portion 71 is formed on the outer periphery of the solenoid 31 and is connected to the low-pressure fuel discharge passage 62 by a low-pressure passage 84. In the space portion 71, the upper side of the low-pressure channel 84 is an elastic body accommodating chamber 7 in which a compression elastic body is accommodated, and the lower space is a low-pressure channel 83. In the first embodiment, the space portion 71 is disposed between the low pressure flow paths 83 and 84, but may be integrated with the low pressure flow path 83 as described above.

  Next, the operation of the injector I of the present invention and the damper effect of the compression elastic body in the elastic body accommodating chamber 7 will be described in detail with reference to FIGS. 1 and 4 to 6.

  In FIG. 4, when the solenoid 31 is energized, the solenoid 31 attracts the armature 32 and the valve needle 36 is displaced upward. Then, the valve body 35 is opened by receiving the fuel pressure in the first discharge hole 67 from the pressure control chamber 21 to the first valve chamber 34, and the high-pressure fuel in the pressure control chamber 21 passes through the first discharge hole 67 to the first level. 1 valve chamber 34 flows out. The spilled fuel passes through the armature chamber 33, the space 71 (low pressure channel 83) below the elastic body containing chamber 7, and the low pressure channel 84 from the low pressure channel 82 that opens to the top surface of the first valve chamber 34. It is discharged to the discharge channel 62.

  Here, the fuel pressure of the common rail supplied to the pressure control chamber 21 is a high pressure of 200 MPa, for example. When this high-pressure fuel is suddenly ejected into the low-pressure fuel (for example, 0.1 MPa) in the first valve chamber 34, the pressure is rapidly lowered, and thus, reduced-pressure boiling, cavitation, and the like occur, and the gas G0 (degassed from the fuel) ● in the figure occurs. The gas G0 goes to the low-pressure fuel discharge passage 62 together with the fuel F. However, since the specific gravity is smaller than that of the fuel F, the gas G0 tends to move upward in the vertical direction, and further upwards when reaching the low-pressure passage 83 from the armature chamber 33. It collects in the elastic body accommodating chamber 7 which moves and becomes a dead end. In this way, the elastic body accommodating chamber 7 is always filled with the compression elastic body G, and when the predetermined capacity is exceeded, excess gas G1 (◯ in the figure) is discharged from the low pressure flow path 84 at the bottom. It is discharged to the flow path 62.

  At this time, the high-pressure fuel in the pressure control chamber 21 is discharged, so that the pressure in the pressure control chamber 21 that is the back pressure of the hydraulic switching valve 4 decreases. Then, in the second valve chamber 22 in FIG. 1, the valve body portion 4 a is separated from the lower seat and displaced upward to be seated on the upper seat. In this state, the valve body portion 4a blocks between the second valve chamber 22 and the high-pressure fuel introduction passage 61, prohibiting the supply of high-pressure fuel to the second valve chamber 22, and the second discharge hole 64 is opened, and the fuel in the nozzle needle back pressure chamber 5 flows out to the low pressure fuel discharge passage 62 through the orifice 52, the communication passage 51, the second valve chamber 22, and the low pressure branch passage 65. As a result, the pressure in the nozzle needle back pressure chamber 5 is lowered, and when the pressure becomes equal to or lower than the valve opening pressure, the nozzle needle 11 is lifted and fuel injection is started from the nozzle hole 12.

  On the other hand, as shown in FIG. 5, when energization to the solenoid 31 is stopped and the electromagnetic control valve 3 is closed, the armature 32 and the valve needle 36 are displaced downward, and the valve body 35 closes the first discharge hole 67. (Figure 5 left half). At this time, since the pressure control chamber 21 and the low-pressure fuel discharge passage 62 are blocked, the fuel pressure in the pressure control chamber 21 rises and the hydraulic switching valve 4 in FIG. 1 is separated from the upper seat. And sit on the lower seat. In this state, the second valve chamber 22 and the low-pressure fuel discharge passage 62 are shut off, and the needle back pressure chamber passes through the high-pressure fuel introduction passage 61, the high-pressure branch passage 63, the second valve chamber 22, and the communication passage 51. 5 is supplied with high-pressure fuel. When the pressure in the needle back pressure chamber 5 increases and becomes equal to or higher than the valve closing pressure, the nozzle needle 11 is closed and the fuel injection is terminated.

  The injector I configured as described above controls the communication between the needle back pressure chamber 5 and the low pressure fuel discharge passage 62 and the switching between them by the hydraulic switching valve 4 that is hydraulically driven. The solenoid 31 can be set without depending on the specifications of the solenoid 31, and the size of the solenoid 31 can be reduced. However, in this case, the spring force of the coil spring 38 that biases the armature 32 in the valve closing direction of the valve element 35 is also set small, and the operation of the electromagnetic control valve 3 is likely to become unstable due to the influence of external force.

  For this reason, in the conventional structure which does not have the elastic body accommodating chamber 7, as shown by a dotted line in FIG. 11, linearity cannot be obtained with respect to the drive pulse from the ECU. As shown in FIG. 12, it is considered that the pressure fluctuations in the first valve chamber 34 and the armature chamber 33 are greatly affected. For example, when the high-pressure fuel is suddenly ejected into the first valve chamber 34 when the electromagnetic control valve 3 is opened, the pressure in the first valve chamber 34 and the armature chamber 33 communicating with the first valve chamber 34 instantaneously increases (see FIG. 12). State A), the force to lift the valve body 35 is increased. For this reason, while in the state A, the electromagnetic control valve 3 cannot be closed at a desired timing. After that, when the fuel is discharged through the low-pressure channels 83 and 84 and the pressure in each chamber drops (state B in FIG. 12), the electromagnetic control valve 3 can be closed at a desired timing.

  With these states A and B, the linearity of the control valve opening time (injection amount) with respect to the drive pulse width is deteriorated, and the injection amount controllability is deteriorated. That is, when the drive pulse width is large (the injection amount is large) as shown in FIG. 11, linearity is obtained, but when the drive pulse width is small (the injection amount is small), the descending of the electromagnetic control valve 3 is delayed. The injection amount increases from the target value. In the state A of FIG. 12, there are two pressure rise peaks because after the electromagnetic control valve 3 is opened, the hydraulic switching valve 4 opens the second discharge hole 64 and the nozzle needle back. This is because the fuel in the pressure chamber 5 flows out through the second valve chamber 22 and the pressure in the low-pressure fuel discharge passage 62 increases. Since this pressure increase is propagated to the armature chamber 33 and the first valve chamber 34 that communicate with each other via the low-pressure channel 84, the oil pressure acting on the armature 32 changes, and the valve closing timing of the valve body 35 varies. .

  On the other hand, as shown in the right half of FIG. 5, in the configuration of the present invention in which the elastic body accommodating chamber 7 is provided, the instantaneous pressure rise as in the state A is caused by the damper of the compression elastic body G that contacts the fuel F. Suppress by effect. That is, when the high-pressure fuel flows into the first valve chamber 34 when the electromagnetic control valve 3 is opened, the boundary surface between the fuel F and the compression elastic body G rises and the compression elastic body G is compressed. However, since the elastic modulus of water (liquid) is 2.1 GPa level and air (gas) is 142 kPa level, the elastic modulus of gas is small, so the pressure rise is small (state C in FIG. 12). That is, the increase in the liquid amount due to the valve opening can be compensated by the volume reduction of the soft gas, and the increase in the liquid pressure can be suppressed. Therefore, as shown in FIG. 11, linearity with respect to the drive pulse width is obtained in the entire region, and the injection amount controllability can be improved.

  FIG. 6 is a diagram showing the state of heat transfer (A) from the solenoid 31 to the compression elastic body G and heat dissipation (B) from the solenoid 31 to the holder B4 constituting the base B. The gas body generally begins to liquefy when the temperature drops. In the above configuration in which the compression elastic body G is accommodated in the elastic body accommodating chamber 7, when the volume of the compression elastic body G is reduced, the above-described damper effect may be reduced. Therefore, in the configurations of the first and second embodiments, the elastic body accommodating chamber 7 is disposed adjacent to the circumferential side surface of the solenoid 31. As a result, the heat generated by the solenoid 31 is transferred (A) to the gas body serving as the compression elastic body G, and the gas body can be kept at a high temperature without being cooled, thereby preventing liquefaction and stabilizing the gas state. Can be

  However, if the periphery of the solenoid 31 is completely covered, there is a risk that the solenoid 31 will be damaged due to insufficient heat dissipation. Therefore, as in the first and second embodiments, it is necessary to dispose the support portion B7 extending from the holder B4 in contact with the outer peripheral side surface of the solenoid 31, and to dissipate heat (B) through the support portion B7. Thus, the elastic body accommodating chamber 7 and the support portion B7 surround the outer periphery of the solenoid 31 at an appropriate ratio in the axial direction, and the heat transfer (A) and the heat dissipation (B) are performed in a well-balanced manner, thereby damaging the solenoid 31. While preventing, a damper effect can be obtained stably.

As shown in FIG. 7 as a third embodiment , which is a reference example of the present invention, the portions for performing heat transfer (A) and heat dissipation (B) may be alternately arranged in the circumferential direction instead of being arranged in the axial direction. it can. FIG. 7 shows a simplified configuration of the back pressure control unit 2 that is a main part of the injector I. The basic structure is the same as that of the second embodiment, and the description thereof is omitted.

  In FIG. 7, a space 71 is formed on the outer periphery of the solenoid 31 above the armature chamber 33 and is connected to the low-pressure fuel discharge passage 62 by a low-pressure passage 84. The space portion 71 has an upper portion of the low-pressure channel 84 divided into six in the circumferential direction, and a function of transferring heat from the elastic body accommodating chamber 7 in which the compression elastic body is accommodated and the solenoid 31 to the holder B4 side. And a radiator B8 having a function of supporting the solenoid 31 are alternately arranged.

  The heat radiating body B8 serving as a support portion is an arc-shaped block body having a predetermined thickness corresponding to the width of the space portion 71, and is made of a metal having high thermal conductivity. The radiator B8 has an arc-shaped outer peripheral surface fixed to the inner peripheral surface of the holder B4, and the arc-shaped inner peripheral surface is in close contact with the outer peripheral side surface of the solenoid 31 to support the solenoid 31, while radiating the heat to the holder B4. To prevent damage from heat. In this embodiment, three heat dissipating bodies B8 are arranged at equal intervals on the outer periphery of the solenoid 31, and three elastic body accommodating chambers 7 in which the compression elastic bodies G are accommodated are formed therebetween.

  The upper end surface of the holder B4 is provided with an annular groove 72 that continues to the outer periphery of the upper end of the space 71, and the three elastic body accommodation chambers 7 communicate with each other through the annular groove 72. The space below the elastic body accommodating chamber 7 and the heat radiating body B8 is a low-pressure channel 83 that follows the armature chamber 33. Also in the configuration of this embodiment, the gas component deaerated in the armature chamber 33 and the first valve chamber 34 is accommodated in the elastic body accommodating chamber 7, and the armature chamber 33 is deformed by the deformation of the compression elastic body G in contact with the low pressure flow path 83. And the same damper effect which suppresses the pressure fluctuation of the 1st valve chamber 34 is acquired. In addition, since the heat radiating body B8 is evenly arranged on the outer periphery of the solenoid 31, heat dissipation from the solenoid 31 is efficiently performed.

  Further, when arranged in the circumferential direction, the length in the contact axis direction of the solenoid 31 and the body B4 can be increased, so that the inclination of the solenoid 31 due to the gap between the inner diameter of the body B4 and the outer diameter of the solenoid 31 can be reduced, and the valve The gap d can be manufactured more stably.

The volume of the elastic body accommodating chamber 7 for obtaining the damper effect (the volume of the compression elastic body G) depends on the amount of high-pressure fuel flowing out and the elastic coefficient of the compression elastic body G, but usually the maximum of the electromagnetic control valve 3 It should be higher than the flow rate, for example, about 10 mm ³ or higher, and is preferably as large as possible. FIG. 13 is a diagram showing the relationship between the volume of the elastic body accommodating chamber 7 and the pressure fluctuation peak value (in the case of the electromagnetic control valve 3 flow rate: 10 mm ³ ), and the pressure fluctuation is suppressed as the elastic body accommodating chamber volume increases. It can be seen that the damper effect is increased. Preferably, the pressure fluctuation peak value greatly decreases at about 5 times or more of the electromagnetic control valve 3, and when it exceeds 10 times, the pressure fluctuation peak value tends to converge, and when it exceeds 15 times, it becomes a substantially constant value. Therefore, preferably, when the range is about 5 to 10 times that of the electromagnetic control valve 3 (about 50 to 100 mm ³ ), the elastic body accommodating chamber 7 is not affected without affecting the flow path configuration around the solenoid 31. It can be set and a damper effect can be obtained efficiently.

The arrangement of the elastic body accommodating chamber 7 is preferably as close to the armature chamber 33 as possible from the viewpoint of suppressing pressure fluctuation. In addition, if there are two discharge flow paths from the electromagnetic control valve 3, the discharge flow passage cross-sectional area becomes larger, so that discharge can be performed earlier and pressure fluctuation can be easily suppressed. Although the structure of the said 1st Embodiment is a structure which makes these compatible, the low pressure flow path 81 by the side of the 1st valve chamber 34 is not connected to the elastic body storage chamber 7, as shown to the said Fig.3 (a). . Therefore, as shown in FIG. 3C as the fourth embodiment, both the first valve chamber 34 and the armature chamber 33 can be connected to the elastic body accommodating chamber 7. An example of this configuration is shown in FIG. FIG. 8 shows the main part configuration of the injector I. The overall configuration and the detailed structure of each part are the same as those in the first embodiment, and the description thereof is omitted.

  In FIG. 8, the electromagnetic control valve 3 constituting the back pressure control unit 2 has a first valve chamber 34 directly connected to the low pressure fuel discharge flow path 62 by a low pressure flow path 81, while an armature by a plurality of low pressure flow paths 82. It communicates with the chamber 33. The solenoid 31 is disposed above the armature chamber 33, but the outer peripheral side thereof is closely supported by the inner peripheral surface of the holder B4, and no space is formed between them. The armature chamber 33 is connected to the low-pressure fuel discharge channel 62 through a low-pressure channel 83 that opens to the side wall, and a low-pressure channel 84 that follows the low-pressure channel 83.

  The low pressure fuel discharge channel 62 is connected to the armature chamber 33 by a plurality of low pressure channels 82 while the first valve chamber 34 is directly connected to the low pressure fuel discharge channel 62 by the low pressure channel 81. The low-pressure fuel discharge flow path 62 extends in the axial direction on the sides of the first valve chamber 34 and the armature chamber 33 and branches above the position where the low-pressure flow path 82 is connected, one of which opens to the tube wall. It is connected to a low-pressure passage that leads to the fuel tank through an outflow hole 68. The other side of the branch path is a stop hole 73 that extends further upward from the branch point and reaches the upper side of the solenoid 31. The inner space of the branch path is an elastic body accommodating chamber 7 ′ in which the compression elastic body G is accommodated. .

  Similar to the above embodiment, the compression elastic body G is a collection of gas degassed by boiling under reduced pressure or cavitation when fuel is ejected into the first valve chamber 34. The gas having a low specific gravity flows out to the low-pressure fuel discharge passage 62 through the low-pressure passages 83 and 84 communicating with the armature chamber 33 or the low-pressure passage 81 communicating with the first valve chamber 34, and further moves upward. It collects in the elastic body accommodating chamber 7 ′ and becomes a gas mass. The volume of the elastic body accommodating chamber 7 ′ is defined by the volume from the upper end of the blind hole 73 to the outflow hole 68. When the volume exceeds the predetermined capacity, the elastic body accommodating chamber 7 ′ is discharged from the bottom outflow hole 68 to the low pressure fuel discharge passage 62. The

  Also in the present embodiment, the compression elastic body G accommodated in the elastic body accommodating chamber 7 ′ is in contact with the fuel flowing through the low-pressure fuel discharge passage 62 downstream of the armature chamber 33, so that the armature chamber 33 and the first The damper effect which suppresses the pressure fluctuation in the valve chamber 34 by the volume change of the compression elastic body G is acquired. Further, the first valve chamber 34 communicates directly with the low-pressure fuel discharge channel 62, and the discharge channel area can be increased. Further, since the elastic body accommodating chamber 7 ′ is formed further upward from the low-pressure fuel discharge channel 62 above the armature chamber 33, the generated gas tends to accumulate in the elastic body accommodating chamber 7 ′.

  As described above, the elastic body accommodating chamber 7 ′ can be formed in the low-pressure fuel discharge channel 62. Since the elastic body accommodating chamber 7 ′ is not in contact with the solenoid 31, the heat dissipating from the engine head side to which the base B is fixed is large, and the elastic body accommodating chamber 7 ′ of the present embodiment is arranged. This is effective when the temperature of the compression elastic body G is small, or when the heat generation of the solenoid 31 is large and the heat radiation area from the solenoid 31 to the holder B4 on the base B side needs to be large.

  FIG. 9 shows a fifth embodiment of the present invention. The basic configuration of this embodiment is the same as that of the fourth embodiment, and a description thereof is omitted. FIG. 9 shows the configuration of the back pressure control unit 2 which is the main part of the injector I. The basic structure is the same as that of the third embodiment, and the compression elastic body G is used as a deformable elastic body containing bag. This is different in that it is accommodated in the elastic bag 9. Hereinafter, the difference will be mainly described.

  Also in the present embodiment, the low-pressure fuel discharge flow path 62 extends in the axial direction on the sides of the first valve chamber 34 and the armature chamber 33 and branches above the position where the low-pressure flow path 82 is connected to the outflow hole 68. Connected to. A stop hole 73 ′ having a diameter larger than that of the low-pressure fuel discharge passage 62 whose upper end extends above the solenoid 31 is formed above the branch point, and an elastic body in which a gas body serving as the compression elastic body G is accommodated in the internal space. It is a containment chamber 7 '. In the electromagnetic control valve 3 constituting the back pressure control unit 2, the first valve chamber 34 is directly connected to the low-pressure fuel discharge channel 62 through the low-pressure channel 81, while the armature chamber 33 communicates with the plurality of low-pressure channels 82. is doing.

  In this embodiment, the compression elastic body G is accommodated in the elastic body accommodating chamber 7 ′ in a state of being filled in a bag-like elastic body bag 9 made of heat-resistant vinyl or the like. It is desirable to use air for the gas body to be the compression elastic body G. When the elastic bag 9 is filled and sealed with the compression elastic body G and a slight internal pressure is applied, the elastic bag 9 is inserted into the stop hole 73 ′ having a larger diameter from the low-pressure fuel discharge passage 62 by the internal pressure. Expands into the elastic body accommodating chamber 7 'and is held and fixed.

  The elastic bag 9 that houses the compression elastic body G is in contact with the fuel flowing through the low-pressure fuel discharge passage 62 below, and the volume changes according to the fuel pressure, so that the pressure of the low-pressure fuel discharge passage 62 is increased. It has the same effect of suppressing fluctuation. Further, in the configuration using the elastic body bag 9 as in the present embodiment, a predetermined capacity of the compression elastic body G can be secured in the elastic body accommodating chamber 7 ′ without depending on deaeration from the fuel. The damper effect can be obtained stably.

  As shown in FIG. 10 as a sixth embodiment of the present invention, the elastic bag 9 may be divided into a plurality of pieces and each bag 91 may be filled with a compression elastic body G. The plurality of bags 91 are joined together and integrated, and the compression bag G as a whole is accommodated in the elastic bag 9. Other configurations are the same as those of the fifth embodiment.

  According to the configuration of the present embodiment, since the elastic bag 9 is divided into a plurality of parts, the deformation is facilitated, and the insertion property of the elastic bag 9 into the low-pressure fuel discharge passage 62 is improved.

  As described above, according to the present invention, the compression elastic body housed in the elastic body housing chamber is brought into contact with the fuel flowing through the low pressure flow path or the low pressure fuel discharge flow path, so that the armature chamber and the first valve chamber are Pressure fluctuation can be suppressed and linearity in injection amount control can be improved.

It is a principal part expanded sectional view of the injector in 1st Embodiment of this invention. It is sectional drawing which shows the whole structure of the injector in 1st Embodiment. (A) is a block diagram showing a schematic configuration of the injector of the first embodiment, (b) is a block diagram showing a schematic configuration of the injector of the second embodiment, and (c) is a schematic configuration of the injector of the fourth embodiment. FIG. It is a schematic sectional drawing explaining generation | occurrence | production of the deaeration gas in the injector of 2nd Embodiment of this invention. It is a schematic sectional drawing explaining the action | operation in the injector of 2nd Embodiment of this invention. It is a schematic sectional drawing explaining the state of solenoid heat transfer and heat dissipation in the injector which becomes 2nd Embodiment of this invention. It is a principal part expanded sectional view of the injector in the 3rd form which is a reference example of this invention. It is a principal part expanded sectional view of the injector in 4th Embodiment of this invention. It is a principal part expanded sectional view of the injector which becomes 5th Embodiment of this invention. It is a principal part expanded sectional view of the injector which becomes 6th Embodiment of this invention. It is a figure which shows the effect to the injection amount controllability by the elastic body accommodating chamber of this invention compared with the conventional structure which does not provide an elastic body accommodating chamber. It is a figure which shows the effect with respect to the pressure fluctuation of the armature chamber and the 1st valve chamber by the elastic body accommodating chamber of this invention compared with the conventional structure which does not provide an elastic body accommodating chamber. It is a figure which shows the relationship between the volume of the elastic body storage chamber of this invention, and a pressure fluctuation peak value.

Explanation of symbols

B Base B4 Holder (Body member)
B7 support part B8 radiator (support part)
DESCRIPTION OF SYMBOLS 1 Nozzle part 11 Nozzle needle 12 Injection hole 2 Back pressure control part 21 Pressure control chamber 22 2nd valve chamber 23 Vertical hole 24 Coil spring 3 Electromagnetic control valve 31 Solenoid (driving body)
32 Armature 33 Armature chamber 34 First valve chamber (valve chamber)
35 Valve body 36 Valve needle 4 Hydraulic switching valve 4a Valve body portion 4b Main body portion 5 Nozzle needle back pressure chamber 51 Communication passage 61 High-pressure fuel introduction passage 62 Low-pressure fuel discharge passage 63 High-pressure branch passage 64 Second discharge hole 65 Low pressure Branch passage 66 Communication passage 67 First discharge hole 71 Space portion 7, 7 'Elastic body accommodating chamber 81-84 Low pressure channel 9 Elastic body bag (elastic body housing bag)
G Compression elastic body

Claims (7)

A pressure control chamber to which high-pressure fuel is supplied from the high-pressure fuel introduction channel;
An electromagnetic control valve that controls communication and blocking between the pressure control chamber and the low-pressure fuel discharge passage;
A nozzle needle that opens and closes an injection hole to inject high-pressure fuel supplied from the high-pressure fuel introduction flow path,
A fuel injection valve that drives the nozzle unit by increasing or decreasing the pressure in the pressure control chamber in accordance with the operation of the electromagnetic control valve,
The electromagnetic control valve has an armature that is suction-driven by a driving body, and a valve body that is integral with the armature.
The valve chamber in which the valve body is accommodated and the armature chamber in which the armature is accommodated are communicated with the low pressure fuel discharge flow path through a low pressure flow path, and the low pressure flow path or the low pressure fuel discharge flow downstream from the armature chamber. In the middle of the path, an elastic body accommodating chamber is provided that accommodates a compression elastic body that is disposed so as to be in contact with the fuel that flows through the low-pressure flow path or the low-pressure fuel discharge flow path and changes the volume by the fuel pressure.
The elastic body accommodating chamber accommodates the compression elastic body in a space formed between the outer peripheral side surface of the driving body and the body member at a position directly above the armature chamber, and the fuel in the armature chamber is The space is to be discharged to the low-pressure fuel discharge path through the low-pressure channel formed in contact with the bottom surface of the compression elastic body, and the space serving as the elastic body accommodating chamber is provided on the outer periphery on the lower end side of the drive body, A fuel injection valve characterized in that a support member is provided on a body member on the outer periphery on the upper end side of the drive body so as to be in contact with the outer peripheral side surface of the upper end side of the drive body so as to be able to transfer heat.   2. The fuel injection valve according to claim 1, wherein the compression elastic body is a gas body separated from a fuel component. 3. The fuel injection valve according to claim 1, wherein the armature chamber is disposed immediately above the valve chamber, and a low-pressure channel is provided to communicate the top surface of the valve chamber and the bottom surface of the armature chamber . A pressure control chamber to which high-pressure fuel is supplied from the high-pressure fuel introduction channel;
An electromagnetic control valve that controls communication and blocking between the pressure control chamber and the low-pressure fuel discharge passage ;
A nozzle needle that opens and closes an injection hole to inject high-pressure fuel supplied from the high-pressure fuel introduction flow path,
A fuel injection valve that drives the nozzle unit by increasing or decreasing the pressure in the pressure control chamber in accordance with the operation of the electromagnetic control valve,
The electromagnetic control valve has an armature that is suction-driven by a driving body, and a valve body that is integral with the armature.
The valve chamber in which the valve body is accommodated and the armature chamber in which the armature is accommodated are communicated with the low pressure fuel discharge channel through a low pressure channel, and the low pressure channel or the low pressure fuel discharge flow downstream from the armature chamber. In the middle of the path, an elastic body accommodating chamber is provided that accommodates a compression elastic body that is disposed so as to be in contact with the fuel that flows through the low-pressure flow path or the low-pressure fuel discharge flow path and changes the volume by the fuel pressure.
The compression elastic body is a gas body separated from the fuel component,
The low-pressure fuel discharge flow path is arranged on the side of the electromagnetic control valve to connect the armature chamber and the valve chamber, and is formed by branching upward from the low-pressure fuel discharge flow path at a position above the armature chamber. A fuel injection valve characterized in that the compression elastic body is accommodated in the space portion to form the elastic body accommodation chamber . 5. The fuel injection valve according to claim 1, wherein the compression elastic body is a gas body filled in a deformable elastic body containing bag . The fuel injection valve according to claim 5, wherein the elastic body containing bag is divided into a plurality of pieces, and each of the divided elastic body containing bags is filled with the compression elastic body . A hydraulic switching valve operated by the pressure in the pressure control chamber;
A nozzle needle back pressure chamber for generating a back pressure of the nozzle needle when high pressure fuel is supplied from the high pressure fuel introduction flow path;
The hydraulic switching valve is configured to switch communication and blocking between the nozzle needle back pressure chamber and the low pressure fuel discharge flow path as the electromagnetic control valve increases or decreases the pressure in the pressure control chamber. The fuel injection valve according to any one of 1 to 6 .