JP4757072B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve mainly used in a fuel supply system of an internal combustion engine, and in particular, a valve body that can be seated on a valve seat connected to an inner end of a fuel injection hole, and urges the valve body in a seating direction. The present invention relates to a fuel injection valve including a return spring, an electromagnetic actuator that operates the valve body in an inward opening direction by energization, and a magnetostrictive actuator that extends by energization a movable part assembly that extends from the valve body to a movable core of the electromagnetic actuator.

Conventionally, a fuel injection valve including a magnetostrictive actuator that opens and closes a valve body by quickly expanding and contracting a magnetostrictive element by applying and releasing a magnetic field is already known as disclosed in Patent Documents 1 and 2.
JP 2002-295330 A JP 2000-257527 A

  By the way, what is disclosed in Patent Document 1 is that a magnetostrictive element of a magnetostrictive actuator is formed in a hollow cylindrical shape surrounding a valve body, and one end on the valve seat side of this magnetostrictive element is fixed to a valve housing, and the other end However, it is difficult to obtain a sufficient amount of extension due to the hollowing of the magnetostrictive element. To achieve this, an extremely long magnetostrictive element is required, leading to an increase in the length of the fuel injection valve, and due to an increase in the weight of the movable part including the valve body, the response of the movable part is reduced, The amount of wear at the contact portion increases.

  In addition, what is disclosed in Patent Document 2 uses a solid magnetostrictive element, and the movable part including the valve body is downsized. It is difficult for the valve part of the valve body to be formed to form the desired fuel spray foam.

  Further, the devices disclosed in Patent Documents 1 and 2 open and close the valve body only by expansion and contraction of the magnetostrictive actuator, resulting in an increase in power consumption.

  The present invention has been made in view of such circumstances, and is a combination of an electromagnetic actuator and a magnetostrictive actuator having a solid magnetostrictive element. An object is to provide a possible fuel injection valve.

  In order to achieve the above object, the present invention provides a valve body that can be seated on a valve seat connected to the inner end of the fuel injection hole, a return spring that biases the valve body in the seating direction, and the valve body by energization. A fuel injection valve comprising: an electromagnetic actuator that operates in an inward opening direction; and a magnetostrictive actuator that extends a movable part assembly extending from the valve body to a movable core of the electromagnetic actuator by energization, wherein the magnetostrictive actuator is connected to the valve body. A solid magnetostrictive element provided so as to connect the movable core of the electromagnetic actuator to a movable core of the electromagnetic actuator via a non-magnetic intermediate member, the valve body and the yoke member A preload spring connected to apply a compressive preload in the axial direction of the valve body to the magnetostrictive element, and the valve body, the movable core, the magnetostrictive element, and the preload spring between them. In Wherein mounted on a valve housing defining a fuel passage connected to the fuel injection hole, and the first, characterized in that the magnetostrictive element is constituted by a second coil for expanding against the preload energized.

  According to the present invention, in addition to the first feature, a journal portion having a diameter larger than that of the movable core and the yoke member and slidably fitted to the inner peripheral surface of the valve housing is provided on the outer periphery of the yoke member. The formation is a second feature.

  In addition to the second feature of the present invention, a pair of coaxially arranged connecting shafts are integrally projected on both end faces of the intermediate member, and these connecting shafts are connected to the movable core and the yoke member, respectively. A third feature is that the movable core, the intermediate member, and the yoke member are integrally connected by press-fitting each into a connection hole provided in an end surface facing the intermediate member.

  Furthermore, in addition to the third feature, the present invention has a fourth feature in which the press-fitting portions of the intermediate member, the movable core, and the yoke member are welded.

  Furthermore, in addition to the fourth feature of the present invention, the outer periphery of the movable core and the yoke member are respectively formed with recesses that are recessed toward the outer peripheral surface of the connecting shaft, and the bottom walls of these recesses are welded to the outer wall. A fifth feature is that each of the connecting shafts is welded.

  In addition to the second feature of the present invention, the movable core assembly comprising the movable core, the intermediate member, and the yoke member is provided with a series of through holes through which both end surfaces in the axial direction communicate to allow fuel to pass. This is the sixth feature.

  According to the first feature of the present invention, the movable part assembly can be extended by extending the magnetostrictive element by energizing the second coil. Therefore, when the electromagnetic actuator is operated to open the valve body, the opening stroke of the movable core of the electromagnetic actuator can be reduced correspondingly by energizing the second coil and quickly extending the movable part assembly. Therefore, the valve opening response of the valve element can be improved.

  Further, even when the valve element is opened, the opening degree of the valve element, that is, the fuel injection amount can be adjusted by appropriately operating the magnetostrictive actuator. Therefore, it is possible to obtain responsiveness and fuel injection rate corresponding to the required characteristics of the engine. In particular, when increasing the opening degree of the valve body, the amount of power supplied to the second coil and the power supply interruption are performed, so that power saving can be achieved.

  In addition, since the magnetostrictive actuator includes a solid magnetostrictive element provided so as to connect the valve body and the movable core, it is possible to provide a sufficient extension amount to the movable part assembly while avoiding an increase in the size of the magnetostrictive actuator. Can do.

  Furthermore, since the valve body is in an inwardly open state when the valve is opened, a spray foam having a desired shape can be obtained without disturbing the valve body.

  Since the movable core of the electromagnetic actuator and the yoke member of the magnetostrictive actuator are integrally connected via a non-magnetic intermediate member, the magnetic flux in the movable core and the yoke can be obtained even in the operating state of the first and second actuators. Interference with the magnetic flux in the member can be blocked by the intermediate member, and a good operating state of each actuator can be ensured.

  According to the second feature of the present invention, the journal portion of the magnetic intermediate member slides on the inner peripheral surface of the valve housing, so that the side gaps between the movable core and the yoke member and the valve housing are always maintained. It can be made uniform and the magnetic characteristics can be stabilized. Further, the friction between the movable core and the yoke member with the valve housing can be prevented as much as possible, and therefore the durability thereof can be enhanced without performing any special wear resistance treatment. Moreover, since the non-magnetic intermediate member can be freely selected from a material having high wear resistance, its own durability can be easily secured.

  According to the third feature of the present invention, it is possible to easily connect the movable core and the yoke member via the intermediate member while improving their coaxial accuracy.

  According to the 4th characteristic of this invention, the connection intensity | strength of each press fit part of the said intermediate member, the said movable core, and a yoke member can be raised.

  According to the fifth feature of the present invention, since the relatively thin bottom walls of the concave portions of the movable core and the yoke member are welded to the connecting shaft of the intermediate member, good welding is possible with very little heat input. As a result, it is possible to avoid a deviation in the coaxial accuracy between the movable core, the intermediate member, and the yoke member due to welding heat, and to prevent a decrease in the hardness of the sliding portion and to ensure wear resistance.

  According to the sixth aspect of the present invention, the fuel can smoothly pass through the movable core assembly without being obstructed by the journal portion of the intermediate member, and the press-fitting loss of the fuel can be suppressed.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 is a longitudinal side view of an engine fuel injection valve according to the present invention, FIG. 2 is an enlarged view of part 2 of FIG. 1, FIG. 3 is an enlarged view of part 3 of FIG. 1, and FIG. 5 is a sectional view taken along line 5-5 of FIG. 3, FIG. 6 is a partially enlarged side view of a preload spring in the fuel injection valve, FIG. 7 is a drive circuit diagram of first and second coils in the fuel injection valve, FIG. 8 is a diagram illustrating a first operation mode of the fuel injection valve, FIG. 9 is a diagram illustrating a second mode of operation of the fuel injection valve, and FIG. 10 is a diagram corresponding to FIG. 3 showing another embodiment of the present invention. is there.

  First, in FIGS. 1 to 3, reference numeral I denotes a direct injection fuel injection valve mounted on a cylinder head of an engine. In the description of the fuel injection valve I, “front” refers to the fuel injection hole 3 side, and “rear” refers to the fuel inlet side.

  A valve housing H of the fuel injection valve I includes a bottomed cylindrical valve seat member 1 having a conical valve seat 2 on the front end wall and a fuel injection hole 3 opened at the center thereof, and a rear of the valve seat member 1. A valve guide tube 4 (magnetic material) fitted to the end and liquid-tightly coupled, and a magnetostrictive housing tube 5 fitted to the rear end of the valve guide tube 4 and liquid-tightly coupled (non-magnetic) Body), a core housing cylinder 6 (magnetic body) that is fitted to the rear end portion of the magnetostrictive housing cylinder 5 and is liquid-tightly coupled thereto, and is fitted to the rear end portion of the core housing cylinder 6 to be liquid-tight. An intermediate cylinder 7 (non-magnetic body) coupled to the hollow cylinder, a hollow cylindrical fixed core 8 (magnetic body) fitted to the rear end portion of the intermediate cylinder 7 and liquid-tightly coupled, and the fixed core 8 It consists of a fuel inlet tube 9 which is liquid-tightly coupled to the rear end.

  A fuel distribution pipe (not shown) for supplying high-pressure fuel is connected to the fuel inlet cylinder 9, and the inside of the valve housing H is connected to the fuel injection hole 3 from the fuel inlet cylinder 9. It becomes the fuel flow path to reach.

  A needle-like valve body 10 having a spherical valve portion that can be seated on the valve seat 2 at the front end is accommodated in the valve guide cylinder 4 so as to secure a cylindrical fuel flow path on the outer periphery thereof. The valve body 10 is opened and closed, that is, separated from and seated on the valve seat 2 to control the injection of the high-pressure fuel in the valve housing H from the fuel injection hole 3.

  A journal portion 12 that is slidably supported on the inner peripheral surface of the valve guide cylinder 4 is formed in an intermediate portion of the valve body 10, and the front and rear end surfaces of the journal portion 12 communicate with each other on the outer periphery. Thus, a chamfer for passing the fuel is provided.

  The magnetostrictive housing cylinder 5 accommodates a cylindrical preload spring 13 (non-magnetic body) and a magnetostrictive element assembly 14 disposed inside thereof. The magnetostrictive element assembly 14 includes a solid and cylindrical inner giant magnetostrictive element 15, a cylindrical outer giant magnetostrictive element 16 disposed so as to surround the inner giant magnetostrictive element 15, and a space between the inner and outer giant magnetostrictive elements 15 and 16. An intermediate cylindrical portion 17a disposed at the front end, a front end member 17b (magnetic body) formed at the front end of the intermediate cylindrical portion 17a (non-magnetic body) and supporting the front end of the outer giant magnetostrictive element 16, and a rear end of the intermediate cylindrical portion 17a The displacement transmitting member 17 is formed of a rear end member 17c (magnetic body) that is formed at the end and supports the rear end of the inner giant magnetostrictive element 15. The displacement transmitting member 17 substantially connects the inner giant magnetostrictive element 15 and the outer giant magnetostrictive element 16 to each other in the axial direction.

  The core housing cylinder 6 has a movable core / yoke member combined body 25 in which a yoke member 22 (magnetic body) is connected to a front end of a movable core 24 (magnetic body) via an intermediate member 23 (nonmagnetic body). Be contained.

  On the outer periphery of the movable core 24 and the intermediate member 23, annular journal portions 18 and 19 are formed so as to protrude and slidably fit to the inner peripheral surfaces of the intermediate cylinder 7 and the core housing cylinder 6. As a result, the movable core / yoke member assembly 25 can be maintained in a stable sliding posture without inclination. Further, the side gaps of the movable core 24 and the intermediate cylinder 7, the yoke member 22 and the core housing cylinder 6 can be made uniform at all times, and the magnetic characteristics can be stabilized. Further, friction between the movable core 24 and the intermediate cylinder 7 and between the yoke member 22 and the core housing cylinder 6 can be prevented as much as possible, and therefore, their durability can be enhanced without performing any special wear resistance treatment. Moreover, since the non-magnetic intermediate member 23 can freely select a material with high wear resistance, it is possible to easily ensure its own durability.

  4 and 5, the connecting structure of the yoke member 22, the intermediate member 23, and the movable core 24 constituting the movable core / yoke member combination 25 will be described. A pair of small-diameter connecting shafts 23 a and 23 b arranged in a coaxial manner are integrally formed on both axial end surfaces of the intermediate member 23. On the other hand, connecting holes 24b and 22b are provided on the end surfaces of the movable core 24 and the yoke member 22 facing the intermediate member 23, and the connecting shafts 23a and 23b are press-fitted into the connecting holes 24b and 22b, respectively. 22-24 are connected integrally. By doing so, the movable core 24 and the yoke member 22 can be easily connected while improving their coaxial accuracy.

  A plurality of recesses 24b and 22b are formed on the outer periphery of the movable core 24 and the yoke member 22 so as to be recessed toward the outer peripheral surfaces of the connecting shafts 23a and 23b, and the bottom walls of these recesses 24b and 22b are formed. Each of the connecting shafts 23a and 23b is welded to the outer periphery. The welding is preferably laser welding. By doing so, it is possible to increase the connection strength of each press-fitting portion between the intermediate member 23 and the movable core 24 and the yoke member 22. In addition, since a relatively small heat input is sufficient to weld the relatively thin bottom walls of the concave portions 24b and 22b of the movable core 24 and the yoke member 22 to the connecting shafts 23a and 23b of the intermediate member 23, the welding heat causes It is possible to avoid a deviation in the coaxial accuracy between the movable core 24, the intermediate member 23, and the yoke member 22.

  The movable core / yoke member assembly 25 configured in this way is provided with a series of through holes 26 that allow the fuel to pass between the front and rear end surfaces. Therefore, the fuel can smoothly pass through the movable core / yoke member assembly 25 without being obstructed by the journal portion 18 of the movable core 24 and the journal portion 19 of the intermediate member 23, and the press-fitting loss of the fuel can be suppressed. , Good fuel injection characteristics can be maintained.

  In FIG. 2 again, the front end member 17b has a guide hole 20 continuous with the hollow portion of the intermediate cylindrical portion 17a of the displacement transmitting member 17, and is formed in the guide hole 20 at the rear end of the valve body 10. The small-diameter shaft portion 10a and the first aligning member 21 (magnetic body) interposed between the small-diameter shaft portion 10a and the inner giant magnetostrictive element 15 are slidably fitted. A gap is provided between the first aligning member 21 and the inner peripheral surface of the guide hole 20 to allow the first aligning member 21 to tilt. The first aligning member 21 has a spherical convex surface 21a at the front end surface, and is always in contact with the central portion of the flat surface 10b at the rear end of the small diameter shaft portion 10a. Therefore, even if the contact end surface of the inner giant magnetostrictive element 15 with the first aligning member 21 is slightly inclined, the first aligning member 21 is also inclined accordingly, but the spherical convex surface of the first aligning member 21 No change occurs in the contact relationship between the small diameter shaft portion 10a of 21a and the flat surface 10b.

  On the other hand, the yoke member 22 is disposed so as to contact the rear end of the outer giant magnetostrictive element 16 via the second alignment member 28. The second alignment member 28 has a guide hole 28a for slidably receiving the rear end member 17c, and the rear end surface is formed into a spherical convex surface 28b. The spherical convex surface 28b and the yoke member 22 The conical concave surface 22c formed on the front end surface is in contact. Therefore, even if the contact end surface of the outer giant magnetostrictive element 16 with the second aligning member 28 is slightly inclined, the second aligning member 28 is also inclined accordingly, but the spherical convex surface of the second aligning member 28 No change occurs in the abutting relationship of 28b with the conical concave surface 22c of the yoke member 22.

  Thus, by the cooperation of the first and second aligning members 21 and 28, the action line of the preload applied to the magnetostrictive element assembly 14 by the preload spring 13 via the yoke member 22 and the valve body 10 is obtained. It is possible to follow the axis of the magnetostrictive element assembly 14, thereby avoiding unnecessary side thrust from being applied to the magnetostrictive element assembly 14 even when the magnetostrictive element assembly 14 is extended, thereby improving its durability. .

  As shown in FIG. 6, the preload spring 13 is made by rolling a punching plate made of a non-magnetic spring steel plate having a large number of through holes 27, 27,. The axially opposite ends of the valve body 10 and the yoke are provided with predetermined axial compressive loads applied to the inner giant magnetostrictive element 15 and the outer giant magnetostrictive element 16. The front end portion of the member 22 is firmly press-fitted and welded to be firmly fixed. Thus, the preload spring 13 applies an axial compressive preload to the inner giant magnetostrictive element 15 and the outer giant magnetostrictive element 16 and holds them in a state of being compressed and deformed by a predetermined amount.

  The preload spring 13 having the above configuration can be formed with a small diameter so that the entire preload spring 13 is close to the outer periphery of the magnetostrictive element assembly 14, and the movable part assembly 43 extending from the movable core 24 to the valve body 10 is compactly configured. be able to. Moreover, the preload spring 13 accommodates the magnetostrictive element assembly 14 in the inside thereof, thereby protecting the magnetostrictive element assembly 14 and ensuring its durability. Since it is housed in the valve housing H together with the preload spring 13, it is not affected by the temperature and humidity of the outside air. Further, even if there is a misalignment between the yoke member 22 and the valve body 10, it is allowed by elastic deformation of the preload spring 13, and no extra addition is applied to the magnetostrictive element assembly 14. 14 stable operations can be ensured.

  The inner giant magnetostrictive element 15 and the outer giant magnetostrictive element 16 are each composed of a plurality of element blocks 15a, 15a; 16a, 16a that are stacked in the axial direction, and between the element blocks 15a, 15a; 16a, 16a. Shims 29 and 30 are interposed.

  As described above, each of the magnetostrictive elements 15 and 16 is divided into a plurality of element blocks and stacked, so that a desired extension amount of the magnetostrictive element assembly 14 is secured and the durability of each of the magnetostrictive elements 15 and 16 is secured. In addition, the length of the magnetostrictive element assembly 14 can be easily adjusted by changing the thickness of the shims 29, 30 interposed between the element blocks 15a, 15a; 16a, 16a. Can do.

  The movable core 24 is disposed so as to face the lower end surface of the fixed core 8 with a gap α corresponding to a predetermined valve opening stroke when the valve body 10 is seated on the valve seat 2. The fixed core 8 has a hollow portion 8a communicating with both front and rear end faces thereof, and a coil-shaped return spring 31 for urging the movable core 24 in the valve closing direction of the valve body 10 in the hollow portion 8a. In order to apply a set load to the return spring 31, a pipe-like retainer 32 that supports the fixed end thereof is provided, and the retainer 32 is fixed to the inner peripheral surface of the hollow portion 8a by screwing or press-fitting. .

  A first coil assembly 35 is disposed on the outer periphery from the rear end portion of the core housing tube 6 to the front end portion of the fixed core. The first coil assembly 35 includes a first bobbin 36 fitted to the outer peripheral surface of the core housing tube 6 from the rear end portion to the front end portion of the fixed core, and a first coil wound around the outer periphery. 37, and a first coil housing cylinder 38 (magnetic body) that accommodates the first coil assembly 35 is disposed so as to connect between the core housing cylinder 6 and the fixed core 8.

  Thus, the first fixed core 8, the movable core 24, the first coil assembly 35, the core housing cylinder 6 and the first coil housing cylinder 38 cooperate with the return spring 31 to open and close the valve body 10. The actuator A1 is configured. When the first coil 37 is energized, a magnetic flux generated by the first coil 37 sequentially travels through the fixed core 8, the first coil housing cylinder 38, the core housing cylinder 6, and the movable core 24. Therefore, the valve body 10 can be opened by suction to the fixed core 8 side.

  A second coil assembly 40 is disposed on the outer periphery of the magnetostrictive housing cylinder 5 so as to correspond to both the giant magnetostrictive elements 15 and 16. The second coil assembly 40 includes a second bobbin 41 fitted to the outer peripheral surface of the magnetostrictive housing cylinder 5 and a second coil 42 wound around the outer periphery. A second coil housing cylinder 44 (magnetic body) that accommodates 40 is disposed so as to connect between the valve guide cylinder 4 and the core housing cylinder 6.

  Thus, the inner giant magnetostrictive element 15, the outer giant magnetostrictive element 16, the displacement transmitting member 17, the preload spring 13, the yoke member 22, the second coil assembly 40, the core housing cylinder 6 and the second coil housing cylinder 44. , A magnetostrictive actuator A2 that can change the effective length of the movable part assembly 43 of the integral movable part from the valve body 10 to the movable core 24 is configured. When the second coil 42 is energized, the magnetic flux generated thereby runs through the second coil housing cylinder 44, the valve guide cylinder 4, the two giant magnetostrictive elements 15, 16, the yoke member 22 and the core housing cylinder 6 in sequence, thereby A magnetic field is applied to the magnetostrictive elements 15 and 16, and both the giant magnetostrictive elements 15 and 16 extend in the axial direction according to the strength of the magnetic field, so that the effective length of the movable part assembly 43 can be extended. At this time, since both the giant magnetostrictive elements 15 and 16 are substantially connected to each other in the axial direction via the displacement transmitting member 17, the elongation in the axial direction of both the giant magnetostrictive elements 15 and 16 is added. The effective length of the movable part assembly 43 is increased. As a result, the magnetostrictive element assembly 14 can be miniaturized and a desired extension amount can be secured.

  By the way, the core housing cylinder 6 (magnetic body) that constitutes a part of the valve housing H and accommodates the movable core / yoke member assembly 25 is composed of the first coil housing (magnetic body) that accommodates the first coil 37. The second coil housing (magnetic body) that accommodates the second coil 42 is disposed so as to be coupled to the magnetic path common to the electromagnetic actuator A1 and the magnetostrictive actuator A2, thereby reducing and extending the number of components. Can contribute to the simplification and compactness of the structure.

  The movable core 24 of the electromagnetic actuator A1 and the yoke member 22 constituting a part of the magnetostrictive actuator A2 are integrally connected via a nonmagnetic intermediate member 23 to form a movable core / yoke member combination 25. Therefore, even when the actuators A1 and A2 are in the operating state, the interference between the magnetic flux in the movable core 24 and the magnetic flux in the yoke member 22 is blocked by the intermediate member 23, so that each actuator A1 and A2 is in a good operating state. Can be secured.

  The first bobbin 36 is integrally formed with a first coupler 47 that supports a first power supply terminal 45 that is connected to the first coil 37, and a second coil housing cylinder 44 is connected to the second coil 42. A second coupler 48 that supports the power supply terminal 46 is integrally formed.

  As shown in FIG. 7, an electronic control unit 53 is connected to the first coil 37 and the second coil 42 via a first drive circuit 51 and a second drive circuit 52, respectively. The first drive circuit 51 and the second drive circuit 52 are individually driven and controlled based on output signals from various sensors (not shown) for detecting the fuel injection timing and the operation state, and the first and second coils 37, The energization timing and energization amount of 42 are individually controlled. At that time, in particular, the energization of the first coil 37 is started prior to the energization of the second coil 42 in consideration of the operation delay of the electromagnetic actuator A1. By doing so, it is possible to compensate for the lower response of the electromagnetic actuator A1 than the response of the magnetostrictive actuator A2.

Next, the operation of the fuel injection valve I will be described.
<First operation mode (see FIG. 8)>
In this first operation mode, when the stroke gap of the movable core 24 with respect to the fixed core 8 when the first and second coils 37 and 42 are not energized is α, the extension of the movable part assembly 43 due to the operation of the magnetostrictive actuator A2. The quantity β is set such that β ≧ α, for example β = α. By utilizing this, the open / close response of the valve body 10 is improved.
(Valve closed mode)
The first and second coils 37 and 42 are in a non-energized state, and the valve body 10 is held in the valve-closed position in which the valve body 10 is seated on the valve seat 2 by the urging force of the return spring 31.
[Valve opening start mode]
First, the first coil 37 is energized, and the second coil 42 is energized after a short delay. However, since the responsiveness of the electromagnetic actuator A1 including the first coil 37 is slightly lower than the responsiveness of the magnetostrictive actuator A2 including the second coil 42, actually, the attracting operation of the movable core 24 toward the fixed core 8 side is not performed. Before starting, the magnetostrictive element assembly 14 expands. As a result, from the relationship of β = α, the movable core 24 quickly moves to the fixed core 8 while maintaining the valve closing position of the valve body 10. Therefore, preparation for opening the valve body 10 can be accelerated.
(Valve open mode)
By the excitation of the first coil 37, the adsorption of the movable core 24 to the fixed core 8 is ensured. Therefore, when the energization of the second coil 42 is cut off, the magnetostrictive element assembly 14 immediately contracts by β = α due to the set load of the preload spring 13 and returns to the initial state. = Leaves the seat by α, which improves the valve opening response. Therefore, the high-pressure fuel that has been waiting inside the valve housing H can be injected from the fuel injection hole 3 into the combustion chamber of the engine at a desired time. Moreover, it is possible to save power by cutting off the energization to the second coil 42.

By the way, the opening of the valve body 10 is an inward opening caused by the displacement of the valve body 10 from the valve seat 2 to the inside of the valve housing H. Therefore, a spray foam formed by fuel injection from the fuel injection hole 3 is used. , Can be satisfactorily formed without being obstructed by the valve portion of the valve body 10.
(Valve closing start mode)
While energizing the first coil 37 is cut off, the second coil 42 is energized. Thus, when the magnetostrictive element assembly 14 is immediately expanded by the energization of the second coil 42, the valve body 10 can be quickly closed and the fuel injection can be stopped.
(Valve closed mode)
The energization of the second coil 42 is also cut off, and the magnetostrictive element assembly 14 is contracted to the initial state. At this stage, since the residual magnetism has disappeared or drastically decreased between the movable core 24 and the fixed core 8, the movable core 24 is pulled away from the fixed core 8 by the set load of the return spring 31 simultaneously with the magnetostrictive element assembly 14. The valve closed state of the valve body 10 can be reliably maintained.

In the valve opening mode, if the amount of energization to the second coil 42 is appropriately reduced or controlled to zero as indicated by the dotted line and the magnetostrictive element assembly 14 is extended by an appropriate amount, the valve element 10 The amount of fuel injection can be reduced by lowering the opening, and this can contribute to power saving.
<Second operation mode (see FIG. 9)>
In this second operation mode, when the stroke gap with respect to the fixed core 8 of the movable core 24 when the first and second coils 37 and 42 are not energized is α, the extension of the movable part assembly 43 due to the operation of the magnetostrictive actuator A2. The quantity β is set such that β <α, for example β = α / 2. By utilizing this, the valve opening response of the valve body 10 is improved, and the fuel injection amount can be varied.
(Valve closed mode)
The first and second coils 37 and 42 are in a non-energized state, and the valve body 10 is held in the valve-closed position in which the valve body 10 is seated on the valve seat 2 by the urging force of the return spring 31. In this state, a gap α corresponding to the maximum valve opening stroke of the valve body 10 is generated between the movable core 24 and the fixed core 8.
[Valve opening start mode]
First, the first coil 37 is energized, and the second coil 42 is energized after a short delay. However, since the responsiveness of the electromagnetic actuator A1 including the first coil 37 is slightly lower than the responsiveness of the magnetostrictive actuator A2 including the second coil 42, actually, the attracting operation of the movable core 24 toward the fixed core 8 side is not performed. Before starting, the magnetostrictive element assembly 14 is extended by β = α / 2, so that the stroke gap between the movable core 24 and the fixed core 8 is reduced from α to α / 2, thereby the first coil 37. Adsorption of the movable core 24 to the fixed core 8 by the excitation of can be accelerated.
(Large valve opening mode)
The energization to the first coil 37 is continued, and the energization to the second coil is cut off. By continuing the energization to the first coil 37, the movable core 24 is immediately adsorbed to the fixed core 8 by the above action, and the valve body 10 is opened. At the same time, the energization to the second coil is interrupted. Since the elongation α / 2 of the magnetostrictive element assembly 14 disappears, the valve body 10 is separated from the maximum stroke amount α valve seat 2 to be fully opened, and a large amount of fuel is injected from the fuel injection hole 3. Can do. Moreover, it is possible to save power by cutting off the energization to the second coil 42.
[Small valve opening mode]
Energization of the first coil 37 is maintained, and energization of the second coil is resumed. Then, in a state where the movable core 24 is attracted to the fixed core 8, the magnetostrictive element assembly 14 is again expanded by α / 2, so that the valve body 10 is close to the valve seat 2 by α / 2 and is in a half-open state. The fuel injection amount from the fuel injection hole 3 can be halved.
(Valve closing start mode)
The energization to the first coil 37 is cut off while the energization to the second coil 42 is maintained. As a result, the valve body 10 is seated on the valve seat 2 by the urging force of the return spring 31 from the half-open state, so that the valve closing impact is small and vibration of the valve body 10 can be prevented.
(Valve closed mode)
Finally, the power supply to the second coil 42 is also cut off. As a result, the movable part assembly 43 contracts, but the valve closing state due to the urging force of the return spring 31 of the valve body 10 is not changed.

  Next, another embodiment of the present invention shown in FIG. 10 will be described.

  In this alternative embodiment, the preload spring 13 is formed of a non-magnetic steel bellows body, and the end portions of the yoke member 22 and the valve body 10 are press-fitted and welded to the openings at both ends in the axial direction. The inside of the load spring 13 is sealed. Since other configurations are the same as those of the previous embodiment, portions corresponding to those of the previous embodiment in FIG. 10 are denoted by the same reference numerals, and redundant description is omitted.

  According to this embodiment, the inside of the preload spring 13 is hermetically sealed so that the magnetostrictive element assembly 14 is cut off from the fuel in the valve housing H, so that the performance degradation of each of the giant magnetostrictive elements 15 and 16 is reduced. Can be suppressed.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, the relationship and operation mode of α and β can be freely changed according to the required characteristics of the engine.

The longitudinal section side view of the fuel injection valve for engines of the present invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. 3 is an enlarged view of part 3 of FIG. FIG. 4 is a sectional view taken along line 4-4 of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. A partially enlarged side view of a preload spring in the fuel injection valve. The drive circuit diagram of the 1st and 2nd coil in the fuel injection valve. Explanatory drawing of the 1st operation | movement aspect of the fuel injection valve. Explanatory drawing of the 2nd operation | movement aspect of the fuel injection valve. FIG. 4 is a view corresponding to FIG. 3 showing another embodiment of the present invention.

Explanation of symbols

I ... Fuel injection valve H ... Valve housing A1 ... Electromagnetic actuator A2 ... Magnetostrictive actuator 2 ... Valve seat 3 ... Fuel injection hole 10 ... ... Valve element 13 ... Preload spring 15 ... Solid magnetostrictive element (inner giant magnetostrictive element)
19 ··· Journal portion 22 ··· Yoke member 22a ··· Connection hole 22b ··· concave portion 23 ··· Intermediate members 23a and 23b · · · Connection shaft 24 ··· movable core 24a ··· · Connection hole 24b ··· concave portion 25 ··· movable core assembly 31 ··· return spring 37 ··· first coil 38 ··· first coil housing tube 42 ··· second coil 43... Second coil housing cylinder

Claims (6)

A valve body (10) that can be seated on a valve seat (2) connected to the inner end of the fuel injection hole (3), a return spring (31) that biases the valve body (10) in the seating direction, The electromagnetic actuator (A1) that operates the valve element (10) in the inward opening direction and the movable part assembly (43) extending from the valve element (10) to the movable core (24) of the electromagnetic actuator (A1) by energization A fuel injection valve comprising a magnetostrictive actuator (A2)
A yoke member (22) for integrally connecting the magnetostrictive actuator (A2) to the movable core (24) of the valve body (10) and the electromagnetic actuator (A1) via a nonmagnetic intermediate member (23). Between the valve element (15) and the yoke member (22), and between the valve element (15) and the valve element (10). And a preload spring (13) connected so as to apply an axial compression preload, and the valve element (10), movable core (24), magnetostrictive element (15) and preload spring (13). Between them, the magnetostrictive element (15) is attached to a valve housing (H) that forms a fuel flow passage connected to the fuel injection hole (3) and extends against the preload when energized. And the second coil (42) to be configured Fuel injection valve that. The fuel injection valve according to claim 1, wherein
A journal portion (19) having a larger diameter than the movable core (24) and the yoke member (22) on the outer periphery of the yoke member (22) and slidably fitted to the inner peripheral surface of the valve housing (H). The fuel injection valve characterized by forming. The fuel injection valve according to claim 2,
A pair of connecting shafts (23a, 23b) arranged coaxially on both end faces of the intermediate member (23) are integrally projected, and these connecting shafts (23a, 23b) are connected to the movable core (24) and the yoke member ( 22), the movable core (24), the intermediate member (23), and the yoke member (22) are integrated with each other by press-fitting into connection holes (24a, 22a) provided on the end faces of the intermediate member (23) facing the intermediate member (23). A fuel injection valve connected to the fuel injection valve. The fuel injection valve according to claim 3,
A fuel injection valve, wherein the press-fitting portions of the intermediate member (23), the movable core (24) and the yoke member (22) are welded. The fuel injection valve according to claim 4, wherein
Recesses (24b, 22b) that are recessed toward the outer peripheral surface of the connecting shaft (23a, 23b) are formed on the outer periphery of the movable core (24) and the yoke member (22), respectively. A fuel injection valve characterized in that the bottom wall of each is welded to the connecting shaft (23a, 23b) by welding. The fuel injection valve according to claim 2,
A series of through-holes (26) for allowing fuel to pass through the movable core assembly (25) composed of the movable core (24), the intermediate member (23) and the yoke member (22) through both axial end surfaces thereof. A fuel injection valve provided.

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