JP2008025390A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve simple in structure capable of suppressing the generation of deposit by discharging residual fuel in an injection part. <P>SOLUTION: A housing hole 423 is formed at the tip 425 of a valve element 42, a piston 81 having a predetermined mass and a spring 82 restoring and urging the piston 81 are disposed in the housing hole 423. When a valve seat 421 is located on a valve seat surface 415, in a flattened fuel reservoir chamber 84 formed by a flat face of the tip 425 of the valve element 42 and the flat face of the tip inside 147 of a valve body 41, the piston 81 is projected by inertial force and abutted on the tip inside 417 of the valve body 41, so that the residual fuel in the fuel reservoir chamber 84 is pushed out and the residual fuel in a plurality of inclined injection holes 414 is discharged by the pushed-out residual fuel so as to suppress the generation of deposit in the injection part 414. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel injection valve, and moreover, a fuel injection valve provided with a plurality of injection hole portions and having a predetermined angle that the hole axis opens outward with respect to the moving direction of the valve body. Therefore, it is suitable for a fuel injection valve of a gasoline direct injection engine.

  In a fuel injection valve used in a gasoline direct injection engine or the like, the valve body at the tip of the fuel injection valve is exposed to a high temperature environment in the combustion chamber of the engine. In particular, the nozzle hole provided in the valve body is exposed to a high-temperature environment, and fuel-derived carbides are generated as deposits on the inner wall of the nozzle hole, causing a decrease in fuel injection amount and abnormal spray shape. This measure is a major issue.

Therefore, as a technique for solving this problem, in Patent Document 1 below, a second needle valve 25 is provided in the center of the first needle valve 17 for injecting and stopping fuel, and the second needle valve 25 is provided in the injection hole 14. A configuration is described in which the fuel remaining in the injection hole 14 flows out into the combustion chamber 4 and is removed.
Japanese Patent Laid-Open No. 11-287169

  However, in the fuel injection valve described in Patent Document 1, the diameter of the normal injection hole is usually very small, and the diameter of the second needle valve 25 is required to advance the second needle valve 25 into the injection hole having the small diameter. There is a difficulty in manufacturing and assembly accuracy. Therefore, the nozzle hole needs to have a certain size.

  Further, the hole axis of the injection hole 14 needs to coincide with the moving direction of the second needle valve 25, and is formed at an angle with respect to the moving direction of the needle valve that causes the residual fuel to flow out and be removed. It cannot be applied to a fuel injection valve having an injection hole. Further, in the fuel injection valve described in Patent Document 1, a complicated mechanism is provided that allows the second needle valve 25 to enter the center of the first needle valve 17 and enter the injection hole 14 when the first needle valve 17 is closed. I need. Furthermore, in the fuel injection valve described in Patent Document 1, the shape of the tip of the first needle valve 17 is in a recessed or protruding state, and dead volume formed by closing the first needle valve 17. Since the residual fuel reservoir chamber called a complex space chamber is formed, the residual fuel in the fuel reservoir chamber cannot be sufficiently extruded even if the second needle valve 25 enters the fuel reservoir chamber.

  Therefore, the inventor forcibly pushes out the residual fuel in the residual fuel reservoir chamber formed when the valve body (needle valve) is closed, and discharges the residual fuel in the nozzle hole by the pushed fuel. Pay attention. It has also been found that the residual fuel can be pushed out sufficiently by making the residual fuel reservoir chamber a flat chamber.

  In view of the above points, the present invention includes a residual fuel discharging means for extruding the fuel remaining in the fuel reservoir chamber formed when the valve body is closed when the valve body is closed, An object of the present invention is to provide a fuel injection valve that discharges residual fuel in a nozzle hole portion with a simple structure and can suppress generation of deposits.

In the invention which concerns on Claim 1, it has a valve body which has a valve seat surface part in the inner side of an injection hole part and the said injection hole part, and has a valve seat part in the front-end | tip, and moves to the axial direction inside the said valve body A valve body mounted in an enabled manner, and the valve seat portion of the valve body and the valve seat surface portion of the valve body are separated and seated by the operation of a driving body, whereby the fuel is injected. In the fuel injection valve that performs injection and stop from the hole,
When the valve seat portion is seated on the valve seat surface portion, a fuel reservoir chamber communicating with the nozzle hole portion is formed by the tip portion of the valve body and the tip inner side portion of the valve body, and the seat portion is the valve Residual fuel discharge means for extruding the fuel remaining in the fuel reservoir chamber after being seated on the seat surface and discharging the residual fuel in the nozzle hole by the extruded fuel is provided.

  According to the above configuration, the fuel remaining in the fuel reservoir chamber is forcibly pushed out by the residual fuel discharge means by the inertia protrusion restoration mechanism or the piezo element, and the remaining fuel in the nozzle hole portion is forced by the force of the pushed residual fuel. Since the fuel is discharged, there is no need for a complicated valve needle mechanism for entering into the injection hole portion as in the prior art. Therefore, it is possible to suppress the formation of deposits by the residual fuel in the injection hole portion with a simple structure. Demonstrate the effect you can. The present invention can also be applied to a fuel injection valve having a structure in which a plurality of injection hole portions exist or a structure in which the axis of the injection hole portion does not coincide with the moving direction of the valve body.

  In the invention according to claim 2, at the position immediately before seating when the valve body is shifted from opening to closing, the tip of the valve body allows the residual fuel discharge means to be accommodated inside the valve body. However, the plane that is integral with the valve body and orthogonal to the moving direction of the valve body is maintained, and the inner end portion of the valve body is formed in a parallel plane that faces the plane of the valve body, and the fuel The reservoir chamber is a chamber sandwiched between two surfaces of the flat surface of the valve body and the parallel plane of the valve body, and the two surfaces are formed in a flat shape so as to be orthogonal to the moving direction of the valve body, When the valve body is seated, the residual fuel discharging means is provided so as to protrude to the position of the inner end portion of the valve body in the fuel reservoir chamber.

  According to the above configuration, in a position immediately before seating when the valve body is shifted from opening to closing, a plane orthogonal to the moving direction of the valve body maintained at the tip of the valve body, and the valve Since the fuel reservoir chamber is formed as a flat chamber with the plane on the inner side of the front end of the body facing and parallel to each other, an injection state is formed by forming a flat fuel reservoir chamber orthogonal to the moving direction of the valve element The flow of the jet in the flow is improved and the jet atomization is not hindered. Further, since the fuel reservoir chamber is a flat chamber, the residual fuel in the fuel reservoir chamber is uniformly pushed out in the flat direction when the residual fuel discharge means protrudes into the flat fuel reservoir chamber. Can do. Therefore, this is effective for a fuel injection valve in which a plurality of nozzle holes are provided and the hole axis of the nozzle has a predetermined angle with respect to the moving direction of the valve body.

  According to a third aspect of the present invention, the residual fuel discharging means is provided inside the distal end portion of the valve body, and the movement of the valve body in the seating direction is stopped by the seating of the valve seat portion on the valve seat surface portion. In this case, an inertia projecting and restoring mechanism that projects into the fuel reservoir chamber by inertia force and maintains the restored state as the valve body moves in the seating direction is provided.

  According to the above configuration, since the residual fuel discharging means is a projecting restoration mechanism using inertia, no electric means for controlling is required, and therefore, the inside of the nozzle hole portion is surely secured with a simple mechanical structure. The remaining fuel can be discharged to prevent the formation of deposits. Further, the bounding of the valve body can be absorbed and prevented by the inertial protrusion restoring mechanism.

  In the invention according to claim 4, the inertial protrusion restoring mechanism is formed in the valve body so as to open to the fuel reservoir chamber, and is stored in a predetermined manner in a storage hole having a depth in the axial direction thereof. A piston having a mass; and a return member for restoring the inertial protrusion of the piston.

  According to the above configuration, the inertial protrusion restoring mechanism is constituted by a piston having a predetermined inertial mass that is movably disposed in a storage hole provided in the valve body, and a return member that restores the inertial protrusion of the piston. Therefore, the structure is extremely simple, and it is possible to reliably project and restore into the fuel reservoir chamber by the inertia force of the piston.

  In the invention according to claim 5, the return member is a base fixed to the tip of the valve body, and a spring that abuts the base and the piston and biases the piston in the restoring direction.

  According to the said structure, since the said return member is made into the spring, urging | biasing force acts reliably and a piston can be decompress | restored reliably.

  In the invention which concerns on Claim 6, the said return member is used as the elastic member with which the inner peripheral part of the said storage hole and the outer peripheral part of the said piston were mounted | worn in the press-contact state.

  According to the said structure, since the said return member is made into the elastic member, a structure is very simple and the urging | biasing to the restoring direction of the said piston is exhibited.

  In the invention according to claim 7, the elastic member is a cylindrical heat-resistant rubber having a predetermined length.

  According to the above configuration, since the elastic member is made of heat and oil resistant rubber, it is lightweight and inexpensive and can be used even in a high temperature environment. Further, since the rubber has a cylindrical shape having a predetermined length, the rubber is compressed and deformed with the movement of the piston, and a sufficient restoring biasing force can be exhibited by the compression and deformation.

  In the invention according to claim 8, the residual fuel discharging means is a piezo element that is expanded and contracted by being energized after the seat portion is seated on the valve seat surface portion.

  According to the above configuration, since the residual fuel discharge means is electrically controlled as a piezo element, the residual fuel can be pushed out in the fuel reservoir chamber instantaneously and a plurality of times of expansion and contraction vibration. The residual fuel in the nozzle hole can be reliably discharged.

  In the invention which concerns on Claim 9, the said piezoelectric element is accommodated in the said accommodating hole so that the expansion-contraction direction of this piezoelectric element may correspond with the moving direction of the said valve body.

  According to the above configuration, the expansion / contraction direction of the piezo element is made to coincide with the moving direction of the valve body, so that the residual fuel in the fuel reservoir chamber can be pushed out efficiently. Further, since the piezo element is mounted in the storage hole, the structure is compact. Further, since no return member is required, the outer diameter of the piezo element can be made substantially the same as the inner diameter of the accommodation hole 423, and the amount of remaining fuel pushed out in the fuel reservoir chamber can be increased. Therefore, the residual fuel in the nozzle hole can be discharged more reliably.

  In the invention according to claim 10, the residual fuel discharging means is a piezo element mounted in the valve body so that the expansion / contraction direction coincides with the moving direction of the valve body.

  According to the above configuration, the expansion and contraction vibration of the piezo element can be generated in the valve body a plurality of times in the movement direction of the valve body, and accordingly, the fuel reservoir located at the tip of the valve body by the expansion and contraction vibration. Residual fuel in the room can be extruded into the nozzle hole. Further, the size of the piezoelectric element in the radial direction can be increased, and the stretching vibration can be strengthened.

  According to an eleventh aspect of the invention, the fuel injection valve according to any one of the first to tenth aspects is provided with a plurality of injection hole portions, and the hole axis is outward with respect to the moving direction of the valve body. Applicable to fuel injection valve having a predetermined angle opening to

  According to the above configuration, since the residual fuel in the nozzle hole is discharged by pushing only the residual fuel in the fuel reservoir chamber, a plurality of nozzle holes are provided, or the hole axis of the nozzle hole is a valve. Even if the fuel injection valve has a predetermined angle that opens outward with respect to the body movement direction, the residual fuel in the injection hole can be discharged without requiring any complicated mechanism.

  In the invention which concerns on Claim 12, the fuel injection valve as described in any one of Claims 1-11 is applied to the fuel injection valve of a gasoline engine.

  According to the above configuration, since the high-grade fuel injection valve that can suppress the generation of deposits in the nozzle hole portion is applied to the gasoline engine, the gasoline engine can be operated without causing a decrease in the fuel injection amount or an abnormality in the spray shape. Can be operated.

  Embodiments of a fuel injection valve according to the present invention will be described below with reference to the drawings. 1, FIG. 2 and FIG. 7 show a first embodiment of the present invention. FIG. 7 is a cross-sectional view of the entire configuration, and FIGS. 1 and 2 show a main part of the present invention and a partially enlarged cross section of FIG. FIG. FIG. 1 shows a valve open state, and FIG. 2 shows a valve closed state.

  The overall structure of the fuel injection valve according to the present invention will be described with reference to FIG. The fuel injection valve 1 of the present invention includes a drive unit 2 that vibrates by energization, a fuel injection unit 4 that injects fuel by the operation of the drive unit 2, and a fuel injection unit that introduces high-pressure fuel from outside and passes through the drive unit 2. 4 includes a fuel introduction portion 6 that supplies the fuel to the fuel cell 4.

  The drive unit 2 has a housing 21, and an electromagnetic solenoid 22 as a drive body is disposed inside the housing 21. The electromagnetic solenoid 22 is pulsed with a voltage controlled by an ECU (not shown) from a power source (not shown) through a terminal 23 incorporated in the housing 21. A cylindrical casing 24 is disposed inside the coil of the electromagnetic solenoid 22 and is fixed to the housing 21 by electric welding.

  Inside the casing 24, a hollow cylindrical stator 25 is fixed to the casing 24, and a movable iron core 26 is disposed so as to be movable in the axial direction. The return spring 27 is inserted into the vertical hole 252 at the center of the stator 25, one end abuts against a stopper 28 press-fitted into the vertical hole 252, and the other end is a step 262 of the vertical hole 261 of the movable iron core 26. The movable iron core 26 is urged downward. When the electromagnetic solenoid 22 is energized, the movable iron core 26 is attracted and comes into contact with the lower end surface portion 251 of the stator 25. When the energization is interrupted, the movable iron core 26 is separated from the lower end surface portion 251 of the stator 25 by the return spring 27. Move to. The stopper 28 can adjust the urging force of the return spring 27 by changing the fixing position with the stator 15.

  The fuel introduction part 6 has a filter body 61, and a fuel introduction port 611 to which high-pressure fuel is supplied is provided in the center part. A fuel filter 62 for removing dust and the like in the introduced fuel is disposed on the downstream side of the introduction port 611. The filter body 61 is fixed to the upper end 241 of the casing 24 by electric welding.

  The fuel injection unit 4 includes a valve body 41 and a valve body 42 that is arranged to be movable inside the valve body 41. The valve body 41 includes a first valve body 411 disposed on the outer periphery of the valve body 42, a second valve body 412 that is closely fixed at the outer periphery and the tip of the first valve body 411, and the second valve body. The third valve body 413 is closely fixed at the outer periphery and the tip of 412. The first, second, and third valve bodies 411, 412, and 413 are fixed and integrated by electric welding on their outer circumferences. The upper end 424 of the valve body 42 and the lower end 264 of the movable iron core 26 are connected and fixed by electric welding.

  The high-pressure fuel supplied from the fuel inlet 611 is filtered by the filter 62, passes through the vertical hole 252 of the stator 25, passes through the vertical hole 261 and the horizontal hole 263 of the movable iron core 26, and the first valve body 411 and the valve body 42. Is supplied into the gap 70 between the two.

  Next, the main part of the first embodiment of the present invention will be described with reference to FIGS. A plurality of injection hole portions 414 are formed on the lower end surface of the second valve body 412 constituting the valve body 41, and the injection hole direction, that is, the axis line of the injection hole portion 414 is relative to the movement direction, that is, the axis line of the valve body 42. And have a certain angle that opens outward. Further, the inner front end portion 417 of the nozzle hole portion 414 on the lower end surface of the second valve body 412 is a horizontal plane orthogonal to the moving direction of the valve body 42.

  A valve seat surface portion 415 is provided on the inner side of the nozzle hole portion 414 at the distal end portion of the first valve body 411 constituting the valve body 41, and the valve seat surface portion 415 is a valve formed at the distal end of the valve body 42. The seat portion 421 is formed in a tapered shape.

  The valve body 42 is provided with guide portions 422 that slide on the inner peripheral wall of the first valve body 411 and stabilize the movement of the valve body 42 in the axial direction at four locations on the outer periphery. The fuel supplied to the gap 70 flows between the gap 422 and the guide portion 422, and is supplied to the valve seat portion 421 and the valve seat surface portion 415.

  A cylindrical housing hole 423 with a bottom and a circular cross-section having a predetermined depth in the axial direction of the moving direction is formed in the center of the front end portion 425 (lower end portion) of the valve body 42. Is formed. Inside the storage hole 423, a metal cylindrical piston 81 having a predetermined mass is disposed so as to be movable in the axial direction, and a tip end portion thereof is a small diameter portion 811. The tip of the portion 811 is flush with the tip 425 of the valve body 42.

  A cylindrical ring-shaped base 83 is press-fitted and fixed to the inner periphery of the tip of the storage hole 423, and the tip of the base 83 is also flush with the tip 425 of the valve body 42. That is, the distal end portion 425 of the valve body 42 maintains a horizontal plane orthogonal to the moving direction of the valve body 42 at the distal end of the valve body 42, the distal end of the base 83, and the distal end of the small diameter portion 811 of the piston 81. (Second valve body 412) It is parallel to the horizontal surface of the inner front end portion 417.

  In addition, the piston 81 is disposed and accommodated so that the tip of the small diameter portion 811 of the piston 81 is positioned in the ring-shaped inner diameter portion of the base portion 83. Further, between the upper end portion of the base portion 83 and the step portion 812 of the small diameter portion 811 of the piston 81, the piston 81 is biased upward, that is, the coil compression for restoring the protrusion due to the inertia of the piston 81 to the original state. A spring 82 is provided. Note that the biasing force of the spring 82 is set to be smaller than the inertial force acting on the piston 81. Accordingly, the piston 81 moves in the same direction as the valve body 42 moves in the direction of the nozzle hole 414, and the piston 81 is moved to the piston 81 by the stop of the valve body 42 (the contact of the valve seat 421 with the valve seat surface portion 415). An inertial force acts, and the inertial force is greater than the urging force of the spring 82 and protrudes toward the injection hole 414. When the piston 81 stops, the urging force of the spring 82 restores the state. The base 83 and the spring 82 constitute a return member, and this return member and the piston 81 in the accommodation hole 423 constitute an inertial protrusion restoring mechanism 80.

  A tapered surface portion 416 extending outward is formed on the lower end surface of the third valve body 413, and the spread and divergence of the fuel injected from the injection hole portion 414 is suppressed, and the fuel is sprayed to a predetermined region.

  Next, the operation of the first embodiment configured as described above will be described. In FIG. 7, when energization, that is, a voltage is applied to the electromagnetic solenoid 22 as a driving body through the terminal 23 under the control of the ECU (not shown), the movable iron core 26 is attracted and moves upward against the urging force of the return spring 27. . As the movable iron core 26 moves, the valve body 42 also moves upward (in the direction of the anti-injection hole portion 414), the valve seat portion 421 is separated from the valve seat surface portion 415, and is supplied into the gap 70 as shown in FIG. The high-pressure fuel is injected from the injection hole portion 414.

  Next, when the electromagnetic solenoid 22 is de-energized, the valve element 42 moves downward (in the direction of the injection hole 414) by the urging force of the return spring 27, and the valve seat portion 421 is seated on the valve seat surface portion 415. Then, the injection of the high-pressure fuel from the nozzle hole portion 414 is stopped.

In a position immediately before the seating when the valve body 42 is shifted from opening to closing, the front end portion 425 of the valve body 42 houses the piston 81 integrally with the valve body 42 in the housing hole 423 of the valve body 42. Maintaining a flat surface without dents or protrusions.
When the valve seat portion 421 is seated on the valve seat surface portion 415, as shown in FIG. 2, the distal end portion 425 of the valve body 42 and the distal end inner side portion 417 of the valve body 41 (first valve body 411, second valve body 412) A fuel reservoir chamber 84 (dead volume) surrounded by and communicating with the nozzle hole portion 414 is formed. The fuel reservoir chamber 84 is a chamber sandwiched between two planes, that is, a plane of the distal end portion 425 of the valve body 42 and a parallel plane of the distal end inner side portion 417 of the valve body 41 (first valve body 411, second valve body 412). Thus, the two surfaces are formed in a flat shape so as to be orthogonal to the moving direction of the valve body 42. Since the flat fuel reservoir chamber 84 is a flat chamber orthogonal to the moving direction of the valve element 42, the flow of the jet flow in the injection state is improved and jet atomization is not hindered. Further, the volume of the fuel reservoir 84 is much larger than the total volume of the nozzle hole 414, and fuel remains in the fuel reservoir 84 and the nozzle hole 414. That is, residual fuel is generated.

  When the movement of the valve body 42 in the direction of the injection hole 414 is stopped by the seating of the valve seat part 421 on the valve seat surface part 415, the piston 81 springs in the accommodation hole 423 in the direction of the injection hole 414 by inertial force. The small-diameter portion 811 projects into the fuel reservoir chamber 84 and comes into contact with the tip inner portion 417 of the valve body 41 (second valve body 412) to stop and retain the stationary inertia. Note that the piston 81 does not advance into the nozzle hole portion 414. Due to the sudden protrusion of the small diameter portion 811 into the fuel reservoir chamber 84 due to the inertial force of the piston 81, the residual fuel in the fuel reservoir chamber 84 is pushed out, and the pushed fuel boosts the residual fuel in the nozzle hole portion 414. Eject well to the outside (inside the engine cylinder). As a result, the residual fuel in the nozzle hole portion 414 is discharged and removed. Therefore, a complicated valve body mechanism for entering into the injection hole portion as in the prior art is not required, and residual fuel in the injection hole portion 414 is removed, so that the generation of carbide deposits in the injection hole portion 414 can be suppressed. At the same time, since the residual fuel in the fuel reservoir 84 is also extruded, the generation of deposits in the fuel reservoir 84 is also suppressed. Since the surface of the piston 81 that protrudes into the fuel reservoir 84 is a flat surface, the amount of fuel remaining in the fuel reservoir 84 is maximized with respect to the movement of the piston 81, and efficient extrusion can be performed.

  Further, in the present invention, since the residual fuel in the fuel reservoir 84 is pushed out using inertial force, the structure in which a plurality of nozzle holes exist and the hole axis of the nozzle hole coincide with the moving direction of the valve body. It can also be applied to a fuel injection valve having a structure that does not. Further, the formed fuel reservoir chamber 84 is a flat chamber orthogonal to the moving direction of the valve element 42. Therefore, when the piston 81 protrudes into the flat fuel reservoir chamber 84, the residual fuel is uniformly distributed in the flat direction. Can be extruded. Therefore, this is effective for a fuel injection valve in which a plurality of nozzle holes are provided and the hole axis of the nozzle has a predetermined angle with respect to the moving direction of the valve body.

  Further, when the valve seat portion 421 is seated on the valve seat surface portion 415, the valve body 42 is bound (jumps) with respect to the valve body 41 due to the metal contact therebetween and tends to move to the anti-injection hole portion 414 (upward). . The movement of the valve body 41 to the anti-injection hole portion 414 is transmitted to the piston 81 through the base 83 and the spring 82. Since the piston 81 maintains a stationary inertia, the anti-injection of the valve body 41 is caused by the static inertia amount. Movement to the hole 414 is suppressed, and the bounce phenomenon of the valve body 41 can be prevented.

  The piston 81 that protrudes into the fuel reservoir chamber 84 and is in a stationary state moves upward in the accommodation hole 423 by the urging force of the spring 82 that forms the return member, and is restored to the state shown in FIG. A voltage is applied to the electromagnetic solenoid 22 in synchronism with the restoration movement of the piston 81, the valve body 42 moves upward, and the valve seat portion 421 is separated from the valve seat surface portion 415.

  In the above-described first embodiment, the residual fuel in the fuel reservoir chamber 84 is pushed out using the inertial force by the inertial protrusion restoration mechanism 80, and the inertial protrusion restoration mechanism 80 is accommodated in the tip of the valve body 42. An inertia piston 81 movably disposed in the hole 423, a base 83 fixed to the tip of the valve body 42, and a spring 82 that urges the piston 81 in a restoring state constitute a return member. .

  Since this inertial protrusion restoring mechanism 80 is a mechanism using inertial force, electrical control is not required, and thus the structure is simple. Further, in the present invention, since the residual fuel in the injection hole portion 414 is discharged by pushing out the residual fuel in the fuel reservoir chamber 84 by the inertial protrusion restoring mechanism 80, the fuel injection valve has a plurality of injection hole portions. Even in the case of a structure having 414 or a structure in which the hole axis of the injection hole portion 414 is inclined at an angle with respect to the moving direction of the valve body 42, an excellent effect in suppressing the generation of deposits is exhibited. Further, since the return member is the spring 82, the urging force acts reliably and the piston 81 can be reliably restored.

  Next, another example of the return member of the piston 81 will be described as a second embodiment with reference to FIGS. The features that differ from the first embodiment with respect to the return member will be described, and the other common parts and structures will be omitted.

  In the second embodiment, the return member is a heat-resistant and oil-resistant fluorine-based rubber 85 that has a hollow cylindrical shape having a predetermined length and has adhesive elasticity. As shown in FIG. 3, the fluoro rubber 85 is press-fitted with the piston 81 in contact with the bottom 426 of the accommodation hole 423 between the inner circumference of the accommodation hole 423 and the outer circumference of the small diameter portion 811 of the piston 81. Has been. The rubber 85 may be a heat and oil resistant silicon-based rubber, and any heat and oil resistant material having adhesive elasticity can be used.

  As described in the first embodiment, when the valve element 42 moves in the direction of the nozzle hole 414 and the valve seat part 421 is seated on the valve seat surface part 415, the movement of the valve element 42 stops. Due to the inertia of the piston 81 due to the stop of the valve body 42, the small diameter portion 811 protrudes into the fuel reservoir 84.

  In this case, since the fluorinated rubber 85 has a predetermined length and is mounted in a press-fit state, the fluorinated rubber 85 itself does not move (slide) with respect to the inertial movement of the piston 81 but is in contact therewith. A compression action is applied to the stepped portion 812 to further expand in the radial direction, the pressure contact force between the inner peripheral portion of the accommodation hole 423 and the outer peripheral portion of the small diameter portion 811 of the piston 81 is increased, and the restoring return member is held more firmly. As a function. Therefore, the rubber 85 exerts an urging force on the piston 81 in the direction of the anti-injection hole 414. The urging force due to elastic deformation of the return member such as rubber 85 is set to be smaller than the inertial force acting on the piston 81.

  The inertial force acting on the piston 81 is greater than the urging force of the rubber 85 as the return member, and the piston 81 projects into the fuel reservoir chamber 84, and its small diameter portion 811 has a tip inner portion 417 of the valve body 41 (second valve body 412). To stop and maintain static inertia. The action of pushing out the residual fuel in the fuel reservoir chamber 84 and discharging the residual fuel in the nozzle hole part 414 is the same as that described in the first embodiment. Then, the piston 81 that protrudes into the fuel reservoir chamber 84 and is in a stationary state moves upward in the accommodation hole 423 by the urging force of the rubber 85 that forms the return member, and is restored to the state shown in FIG.

  In this case, the above-described bounce phenomenon of the valve body 42 is also suppressed by the static inertia of the piston 81 through the rubber 85 in the same manner as described in the first embodiment. In addition, since the return member in the second embodiment is composed of only the rubber 85, the structure is extremely simple and inexpensive. In the second embodiment described above, the rubber 85 as the return member is mounted as a single item in a press-fit state so as not to fall between the inner peripheral portion of the accommodation hole 423 and the outer peripheral portion of the small diameter portion 811 of the piston 81. However, as in the configuration of the spring 82 and the base portion 83 in the first embodiment described above, rubber as a return member is loosened between the inner peripheral portion of the accommodation hole 423 and the outer peripheral portion of the small diameter portion 811 of the piston 81. A ring-shaped base portion that is inserted and prevented from being pulled out may be press-fitted and fixed to the tip of the accommodation hole 423.

  In the first and second embodiments described above, the inertial protrusion restoring mechanism 80 pushes the fuel remaining in the fuel reservoir chamber 84 when the valve seat portion 421 is seated on the valve seat surface portion 415 in the present invention. Thus, residual fuel discharging means for discharging the residual fuel in the nozzle hole portion 414 is provided.

  Next, another example of the residual fuel discharging means in the present invention will be described as a third embodiment with reference to FIG. A common configuration and site | part are abbreviate | omitted with the above-mentioned 1st, 2nd embodiment, and the different feature point is demonstrated. In the housing hole 423 of the valve body 42, a piezoelectric piezo element 90 as a residual fuel discharging means is disposed. A predetermined number of piezo elements 90 are stacked in the moving direction (axial direction) of the valve body 42, and the tip thereof maintains the same horizontal plane as the tip portion 425 of the valve body 42. The number of sheets is set so as to abut on the tip inner portion 417 of the valve body 41 (second valve body 412).

  In addition, a pair of electric wires 91 for supplying voltage is connected to the piezo element 90, is connected to a power source outside the fuel injection valve 1 through a through hole 427 in the valve body 42, and is controlled by an ECU (not shown). Has been. The voltage supplied to the piezo element 90 is applied with a predetermined time delay from the timing of the voltage applied to the electromagnetic solenoid 22 controlled by an ECU (not shown). That is, after the valve seat portion 421 of the valve body 42 is seated on the valve seat surface portion 415, it is applied to the piezo element 90 after a predetermined time.

  The piezoelectric element 90 as the residual fuel discharging means configured as described above is applied with a voltage when the valve seat portion 421 is seated on the valve seat surface portion 415, extends in the direction of the nozzle hole portion 414, and protrudes into the fuel reservoir chamber 84. , Abuts against the tip inner portion 417. The piezo element 90 does not enter the nozzle hole portion 414. The protrusion of the piezo element 90 pushes out the residual fuel in the fuel reservoir chamber 84 and discharges the residual fuel in the injection hole portion 414, thereby preventing the deposit from being generated in the injection hole portion 414. Further, the piezoelectric element 90 can be vibrated several times while the valve seat portion 421 is seated on the valve seat surface portion 415, that is, while the valve body 42 is closed, and the fuel reservoir 84 The residual fuel inside is reliably pushed out. Accordingly, the effect of discharging the residual fuel in the nozzle hole 414 is also great. Further, since the surface of the piezo element 90 protruding into the fuel reservoir chamber 84 is a flat surface, the amount of fuel remaining in the fuel reservoir chamber 84 with respect to the extension of the piezo element 90 is maximized, and efficient extrusion is performed. Can do.

  In the third embodiment, since the return member in the first and second embodiments is not required, the size of the outer diameter of the piezoelectric element 90 can be made substantially the same as the inner diameter of the accommodation hole 423. It is possible to increase the amount of extrusion of the residual fuel in the fuel reservoir 84. Therefore, the residual fuel in the nozzle hole 414 can be discharged more reliably. Further, since the expansion / contraction direction of the piezo element 90 coincides with the moving direction of the valve element 42, the residual fuel in the fuel reservoir chamber 84 can be pushed out efficiently. Furthermore, since the piezo element 90 is mounted in the storage hole 423, it has a compact structure.

  When the piezo element 90 has been extended for a predetermined time, the supply voltage is cut off, the piezo element 90 contracts, and moves together with the valve body 42 toward the counter-injection hole portion 414.

  Next, still another example of the residual fuel discharging means in the present invention will be described as a fourth embodiment with reference to FIG. The common features and parts of the first, second, and third embodiments described above are omitted, and different features will be described.

  Inside the valve body 41, specifically, between the outer peripheral portion of the second valve body 412 and the inner peripheral portion of the third valve body 413, a piezo element 95 is disposed as a residual fuel discharging means. This piezo element 95 has a ring shape and a predetermined number of elements are stacked in the moving direction (axial direction) of the valve body 42. An electric wire (not shown) for supplying a voltage is connected to the piezo element 95, is connected to a power supply outside the fuel injection valve 1 through the valve body 41, and is controlled by an ECU (not shown).

  The voltage supplied to the piezo element 95 is controlled by an ECU (not shown) and applied with a predetermined time delay from the timing of the voltage applied to the electromagnetic solenoid 22. That is, the valve seat portion 421 of the valve body 42 is applied to the piezo element 95 after a predetermined time after sitting on the valve seat surface portion 415. In this case, the voltage applied to the piezo element 95 is set so as to supply a predetermined number of pulses while the valve seat portion 421 is seated on the valve seat surface portion 415.

  In the piezo element 95 as the residual fuel discharging means configured as described above, when the valve seat portion 421 is seated on the valve seat surface portion 415, a voltage is applied in a pulsed manner to expand and contract in the direction of the nozzle hole portion 414. It is transmitted to the tip end of the valve body 41 and imparts vibration to the residual fuel in the fuel reservoir chamber 84 to forcibly push out, discharge the residual fuel in the nozzle hole portion 414, and suppress the generation of deposits.

  In the fourth embodiment, the piezo element 95 can actuate a large number of vibrations while the valve element 42 is closed, so that more residual fuel in the fuel reservoir 84 can be pushed out by the control setting. And the generation of deposits in the nozzle hole portion 414 can be reliably suppressed. Further, the size of the piezo element 95 in the radial direction can be increased, and the stretching vibration can be increased.

  Note that the piston 81, the spring 82, the base 83, and the piezo elements 90 and 95 constituting the inertial protrusion restoring mechanism 80 described above constitute the residual fuel discharging means in the present invention.

In addition, since the high-grade fuel injection valve 1 according to the present invention that can suppress the formation of deposits in the nozzle hole portion 414 is applied to a gasoline engine, the fuel injection amount is reduced without causing a decrease in the fuel injection amount or an abnormality in the spray shape. A gasoline engine can be operated. The fuel injection valve in the present invention is not limited to the structure of the fuel injection valve described above. The injection hole portion may be a single hole and the axis may be the same as the moving direction of the valve body. The driving body that moves the body may be a piezo element or a back pressure mechanism that controls the opening and closing of the valve body.
Furthermore, although the fuel injection valve which becomes this invention demonstrated the example applied to a gasoline direct-injection engine in the above-mentioned embodiment, it may be applied to a diesel engine and is further applied to fuel injection valves, such as another engine. May be.

It is an expanded sectional view which shows the principal part of 1st Embodiment of the fuel injection valve which becomes this invention in a valve opening state. It is an expanded sectional view which shows the principal part of 1st Embodiment of the fuel injection valve which becomes this invention in a valve closing state. It is an expanded sectional view which shows the principal part of 2nd Embodiment of the fuel injection valve which becomes this invention in a valve opening state. It is an expanded sectional view which shows the principal part of 2nd Embodiment of the fuel injection valve which becomes this invention in a valve closing state. It is an expanded sectional view which shows the principal part of 3rd Embodiment of the fuel injection valve which becomes this invention in a valve opening state. It is an expanded sectional view which shows the principal part of 4th Embodiment of the fuel injection valve which becomes this invention in a valve opening state. 1 is an overall cross-sectional view showing a first embodiment of a fuel injection valve according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection valve 2 Drive part 4 Fuel injection part 6 Fuel introduction part 22 Electromagnetic solenoid which makes a drive body 41 Valve body 411 1st valve body 412 2nd valve body 413 3rd valve body 414 Injection hole part 415 Valve seat surface part 417 Tip Inner portion 42 Valve body 421 Valve seat portion 423 Accommodating hole 425 Tip portion 611 Fuel introduction port 80 Inertial protrusion restoring mechanism as residual fuel discharge means 81 Piston 811 Small diameter portion 82 Spring 83 Base portion 85 Elastic member 90, 95 As residual fuel discharge means Piezo element

Claims (12)

A valve body having a valve seat surface portion on the inner side of the nozzle hole portion and the nozzle hole portion;
A valve body having a valve seat at the tip and mounted inside the valve body so as to be movable in the axial direction;
In a fuel injection valve that injects and stops fuel from the injection hole portion by separating and seating the valve seat portion of the valve body and the valve seat surface portion of the valve body by operation of a driving body,
When the valve seat portion is seated on the valve seat surface portion, a fuel reservoir chamber that communicates with the nozzle hole portion is formed by the distal end portion of the valve body and the inner end portion of the valve body,
When the valve seat part is seated on the valve seat surface part, the fuel remaining in the fuel reservoir chamber is pushed out, and residual fuel discharging means for discharging the residual fuel in the nozzle hole part by the pushed fuel is provided. A fuel injection valve characterized by that. At the position immediately before seating when the valve body is shifted from opening to closing, the tip of the valve body is integrated with the valve body while accommodating the residual fuel discharge means inside the valve body. Maintaining a plane orthogonal to the moving direction of the valve body, the tip inner portion of the valve body is formed in a parallel plane facing the plane of the valve body,
The fuel reservoir chamber is a chamber sandwiched between two surfaces of the flat surface of the valve body and the parallel flat surface of the valve body, and the two surfaces are formed in a flat shape so as to be orthogonal to the moving direction of the valve body. And
2. The fuel injection valve according to claim 1, wherein when the valve body is seated, the residual fuel discharge means is provided so as to protrude to a position of the inner end portion of the valve body in the fuel reservoir chamber. .   The residual fuel discharge means is provided inside the tip of the valve body, and when the movement of the valve body in the seating direction is stopped by the seating of the valve seat portion on the valve seat surface portion, an inertial force is used. 3. The fuel injection valve according to claim 1, wherein the fuel injection valve is an inertia protrusion recovery mechanism that protrudes into the fuel reservoir chamber and maintains a recovery state as the valve body moves in a seating direction.   The inertial protrusion restoring mechanism is a piston having a predetermined mass that is formed at the distal end portion of the valve body so as to open to the fuel reservoir chamber, and is movably housed in a housing hole having a depth in the axial direction thereof. The fuel injection valve according to claim 3, further comprising: a return member that restores the inertia protrusion of the piston.   5. The fuel injection according to claim 4, wherein the return member is a base fixed to the tip of the valve body, and a spring that abuts the base and the piston and biases the piston in a restoring direction. valve.   5. The fuel injection valve according to claim 4, wherein the return member is an elastic member mounted in a pressure contact state between an inner peripheral portion of the storage hole and an outer peripheral portion of the piston.   The fuel injection valve according to claim 6, wherein the elastic member is a cylindrical heat and oil resistant rubber having a predetermined length.   3. The fuel injection valve according to claim 1, wherein the residual fuel discharging means is a piezo element that is energized and vibrates and contracts after the valve seat portion is seated on the valve seat surface portion.   9. The fuel injection valve according to claim 8, wherein the piezo element is accommodated in the accommodation hole so that an expansion / contraction direction of the piezo element coincides with a moving direction of the valve body.   2. The fuel injection valve according to claim 1, wherein the residual fuel discharge means is a piezo element mounted in the valve body so that an expansion / contraction direction coincides with a moving direction of the valve body.   The fuel injection valve according to any one of claims 1 to 10, wherein a plurality of nozzle holes are provided, and the hole axis has a predetermined angle that opens outward with respect to the moving direction of the valve body. The fuel injection valve is applied to a fuel injection valve. The fuel injection valve according to any one of claims 1 to 11, wherein the fuel injection valve is applied to a fuel injection valve of a gasoline engine.