JP3890234B2 - Fuel injection valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection valve mounted on an internal combustion engine for controlling a fuel supply amount and an internal combustion engine equipped with the fuel injection valve.
[0002]
[Prior art]
The fuel injection valve includes a fuel injection hole, a valve seat disposed in the vicinity thereof, a valve body that is slidably supported in an axial direction at a position facing the valve seat, and a spring. The spring generates a force that presses the valve body toward the valve seat.
In a state where the valve seat and the valve body are in contact with each other by the spring force, the fuel passage is closed, so that fuel is not injected from the fuel injection hole.
When the valve body slides in the axial direction and is separated from the valve seat by driving means using electromagnetic force or fuel pressure, the fuel passage is opened, so that fuel is injected from the fuel injection hole. Thus, in the fuel injection valve, the fuel supply amount is controlled by switching the position of the valve body.
Here, when the position of the valve body is switched, a collision between the valve seat and the valve body, or a collision between the stopper member and the valve body on the opposite side of the valve seat in the axial direction occurs. The behavior that the valve body bounces at the time of the collision is called bouncing. There are cases where the fixed iron core constituting the magnetic circuit also serves as a stopper member and cases where a stopper member separate from the fixed iron core is provided.
In particular, bouncing due to the collision between the valve body and the stopper member may deteriorate the linearity of the fuel injection amount with respect to the input pulse width to the fuel injection valve, and is desirably suppressed.
As a conventional technique for suppressing bouncing, there is JP-A-5-223031. In this prior art, a hole is provided in a shaft of a valve body (hereinafter referred to as a rod), and magnetic powder is enclosed therein. When the valve body collides with the stopper member, the magnetic powder collides with the upper part of the hole with a certain delay. As a result, the repulsive force acting on the valve body is canceled out to suppress bouncing.
[0003]
[Problems to be solved by the invention]
However, the above prior art has the following problems.
Since it is necessary to provide a hole in the rod of the valve body, if an attempt is made to secure the rigidity of the rod, the outer diameter of the rod will increase, making it difficult to apply to a fuel injection valve having a smaller outer diameter.
Moreover, it is difficult to process a deep hole in the rod.
Moreover, it is necessary to select the mass of the magnetic powder within the range of the hole volume, and it is difficult to select an appropriate mass.
[0004]
An object of the present invention is to solve the above-described problems and to obtain a fuel injection valve equipped with a bouncing suppression structure that does not require a hole in a rod and can be applied to a fuel injection valve having a small outer diameter. Another object of the present invention is to obtain a fuel injection valve equipped with a bouncing suppression structure that is highly effective because an appropriate additional mass can be selected without difficult deep hole machining.
[0005]
[Means for Solving the Problems]
Therefore, in the present invention, a fuel injection hole, a valve seat disposed in the vicinity of the fuel injection hole, a valve body that opens and closes a fuel passage by contact with and separation from the valve seat, and the valve body is connected to the valve seat. A fuel injection valve comprising: a spring pressed against the valve body; an interlocking member separate from the valve body provided between the valve body and the spring; and a drive means for driving the valve body. A movable range restricting portion for restricting a movable range of the interlocking member in a direction away from the valve body is provided.
[0006]
A large-diameter portion may be provided at an end of the interlocking member on the movable iron core side, and the movable range restricting portion may be configured by a stepped portion provided on an inner diameter portion of the movable iron core and engaged with the large-diameter portion.
Further, an elastic member may be provided on the movable range restricting portion.
In the fuel injection valve, a space for confining fuel may be formed in the movable range restricting portion by the interlocking member and the valve body.
Further, an elastic member constituted by a leaf spring is provided in the valve body, and an engaging portion that engages with the valve seat side surface of the leaf spring when the interlocking member moves in a direction away from the valve body, An engagement portion that engages with a surface opposite to the surface of the leaf spring when moved in a direction opposite to the direction is provided, and the movable range of the interlocking member in a direction away from the valve body and the movable range of the said valve body side of the interlocking member is better to be restricted elastically by the leaf spring.
Moreover, it is good to give an abrasion-proof process to the collision part or sliding part of the said interlocking member and the said valve body.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
<FIGS. 1 to 4 First Embodiment>
FIG. 1 shows an embodiment of the fuel injection valve of the present invention.
The orifice plate 1 is provided with a fuel injection hole 2 and a valve seat 3. The orifice plate 1 is fixed to the tip of the nozzle holder 11. A swirler 12 is provided between the orifice plate 1 and the nozzle holder 11. A guide plate 13 is fixed inside the nozzle holder 11. The valve body 4 is guided by a hole provided in the central portion of the guide plate 13 and an inner diameter portion of the swirler 12.
[0008]
The valve body 4 is formed by coupling a movable iron core 5, a cylindrical member 6, and a rod 7. The damper plate 8 provided inside the movable iron core 5 is configured such that the outer peripheral portion 801 is supported by the upper end surface of the cylindrical member 6. The interlocking member 10 is supported inside the inner iron core 9 so as to be slidable in the axial direction. The distal end portion of the interlocking member 10 is brought into contact with the inner peripheral portion 802 of the damper plate 8. The damper plate 8 functions as a leaf spring by supporting the outer peripheral portion 801 and bending the inner peripheral portion 802 in the axial direction.
[0009]
The nozzle holder 11 is fixed inside the nozzle housing 14. A ring 15 for adjusting the stroke of the valve body 4 is provided at the upper end of the nozzle holder 11. A spring pin 19 is fixed inside the inner iron core 9. The spring 20 is provided in a compressed state with the lower end of the spring pin 19 as a fixed end. The spring force is transmitted to the valve body 4 via the interlocking member 10, and the valve body 4 is pressed against the valve seat 3. In this state, since the fuel passage is closed, fuel injection from the fuel injection hole 2 is not performed.
[0010]
The nozzle holder 14, the movable iron core 5, the inner iron core 9, the plate housing 16, and the outer iron core 17 constitute a magnetic circuit that makes a circuit around the coil 18. When a current is passed through the coil 18, the movable iron core 5 is attracted to the inner iron core 9 by electromagnetic force, and the valve body 4 moves to a position where its upper end surface comes into contact with the lower end surface of the inner iron core 9. In this state, since a gap is formed between the valve body 4 and the valve seat 3, the fuel passage is opened, and the fuel supplied from the fuel supply port 21 is given a turning force by the swirler 12, and the fuel injection hole 2. Is injected from.
[0011]
The function of the fuel injection valve is to control the fuel supply amount by switching the position of the valve body 4 as described above.
[0012]
Here, when the position of the valve body 4 is switched, a collision between the valve body 4 and the valve seat 3 and a collision between the valve body 4 and the inner iron core 9 occur. Since the rebound behavior of the valve body 4 that occurs at the time of the collision, so-called bouncing, may cause a slight variation in the fuel injection amount, it is desirable to suppress bouncing.
[0013]
In particular, the present embodiment aims to suppress bouncing due to a collision between the valve body 4 and the inner iron core 9.
[0014]
Therefore, in this embodiment, the large diameter portion 101 is provided at the lower end portion of the interlocking member 10 and is engaged with the step portion 501 provided on the inner diameter of the movable iron core 5. In other words, the valve body 4 is provided with a step portion 501 as a movable range restricting portion that restricts the movable range of the interlocking member 10 toward the spring. The mechanism by which the bouncing of the valve body 4 is suppressed by such a configuration will be described with reference to FIGS.
[0015]
FIG. 2 shows a process in which only the orifice plate 1, the valve body 4, the inner iron core 9, the interlocking member 10, and the spring 20 are taken out from the fuel injection valve, and the process of transition from the closed valve holding state to the open valve holding state is shown in FIG. It is shown in the order of (d).
(A) “Valve closed” represents a state in which the valve body 4 is pressed against the orifice plate 1 by the spring 20.
(B) “Valve open” represents the moment when electromagnetic force is applied by passing a current through a coil (not shown), the valve body 4 is attracted to the inner iron core 9 and the two collide.
(C) In “immediately after valve opening”, even after the valve body 4 and the inner iron core 9 collide, the interlocking member 10 moves upward due to inertia. The large-diameter portion 101 at the lower end portion of the interlocking member 10 engages with the step portion 501 of the movable iron core. As a result, an upward force as indicated by arrow A acts on the valve body 4 from the interlocking member 10. Immediately after the valve is opened, the valve body 4 tries to bounce downward due to the reaction of the collision, but the arrow A which is the upward force from the interlocking member 10 suppresses this. Even when the valve body 4 is sucked and held by the inner iron core 9 and the large-diameter portion 101 is engaged with the step portion 501, the spring 20 should not be in close contact .
(D) “Valve open holding” represents a state in which the interlocking member 10 has returned to the original position again by the spring force.
[0016]
The same process will be described with reference to the graph of FIG. FIG. 3 is a graph showing the input pulse, the current flowing through the coil, and the displacement of the valve body when the valve body 4 is driven in a graph with the horizontal axis taken as time. When the input pulse is turned on, a large current rises and the valve body moves from the valve closing position toward the valve opening position. When the configuration of the present invention is not employed, the valve body 4 collides with the inner iron core 9 at the valve opening position, and then bounces as indicated by the solid line (1). According to the configuration of the present invention, immediately after the valve opening, the interlocking member 10 moves upward due to inertia and engages with the valve body. Therefore, since an upward force is applied from the interlocking member 10 to the valve body 4, bouncing can be suppressed as indicated by the broken line (2).
[0017]
Further, with reference to FIG. 4, the effect of this embodiment will be described in more detail.
[0018]
FIG. 4 is a graph showing the relationship between the input pulse width to the fuel injection valve and the injection amount. When the configuration of the present embodiment is not taken, there may be a characteristic in which the injection amount undulates as indicated by a solid line in a short input pulse width region due to the influence of bouncing at the valve opening position of the valve element 4. When the input pulse is turned off in the region of FIG. 3 (a), the valve body has a negative speed at that time, so the time until the valve returns to the valve closing position is shortened. In such a state, the injection amount is relatively small, and the characteristics shown in FIG. When the input pulse is turned off in the region of FIG. 3 (b), the valve body has a positive speed at that time, so that the time until returning to the valve closing position becomes longer. In such a state, the injection amount becomes relatively large, and the characteristics shown in FIG. According to this embodiment, since the bouncing of the valve body 4 at the valve opening position can be suppressed, the linearity of the injection amount can be maintained even in the short input pulse width region as shown by the broken line in FIG. become.
[0019]
As shown in FIGS. 1 to 4, according to this embodiment, it is not necessary to provide a hole in the rod 7, and therefore a bouncing suppression mechanism is provided without increasing the outer diameter of the rod 7. Can do. Therefore, it is possible to provide a bouncing suppression mechanism even for a fuel injection valve having a small outer diameter. Moreover, the mass of the interlocking member 10 can be adjusted according to its length, and an appropriate value can be selected.
[0020]
Further, according to the present embodiment, the time from (b) to (c) in FIG. 2 is adjusted by adjusting the axial gap between the large-diameter portion 101 of the interlocking member 10 and the step portion 501 of the movable iron core 5. That is, the delay time from when the movable iron core 5 collides with the fixed iron core 9 until the large diameter portion 101 of the interlocking member 10 and the stepped portion 501 of the movable iron core 5 can be adjusted. Therefore, the bouncing suppression effect is high.
<Fig. 5 Elastic member at the movable range regulating portion>
Another embodiment of the fuel injection valve of the present invention will be described with reference to FIG.
[0021]
FIG. 5 is a cross-sectional view showing only the interlocking member 10, the movable iron core 5, the damper plate 8, the cylindrical member 6, and the rod 7 extracted from the fuel injection valve of the present invention.
[0022]
The elastic member 22 is provided between the large diameter portion 101 of the interlocking member 10 and the step portion 501 of the movable iron core 5. The elastic member 22 may be rubber or a metal leaf spring.
[0023]
According to such a configuration, the natural period determined by the spring constant of the elastic member 22 and the mass of the interlocking member 10 is set to a value close to or close to the period of the repulsive force received by the movable core 5 at the time of the valve opening collision. The interlocking member 10 and the elastic member 22 can act as a dynamic vibration absorber. Therefore, the bouncing suppression effect at the time of valve opening can be further enhanced. Moreover, since the vibration and noise which generate | occur | produce at the time of valve opening can be attenuated with the elastic member 22, it can reduce noise.
[0024]
In this embodiment, when a metal leaf spring is used as the elastic member 22, the temperature dependence of the spring constant is lower than when rubber is used, and the bouncing suppression effect is stable against temperature changes. Is obtained. Furthermore, it is excellent in durability.
<Figure 6 Damper room>
Another embodiment of the fuel injection valve of the present invention will be described with reference to FIG.
[0025]
FIG. 6 is a sectional view showing only the interlocking member 10, the movable iron core 5, the damper plate 8, and the tubular member 6 among the fuel injection valves of the present invention.
[0026]
A fuel damper chamber 23 surrounded by the movable iron core 5 and the interlocking member 10 is provided.
[0027]
According to this configuration, when the interlocking member 10 moves in the axial direction relative to the movable iron core 5, the fuel in the fuel damper chamber 23 enters and exits through the gaps 24 and 25. A damping force can be generated. For example, in the process from (b) to (c) in FIG. 2, a damping force that presses the movable iron core 4 upward is generated. This damping force can further enhance the bouncing suppression effect when the valve is opened. Further, since vibration and noise generated when the valve is opened can be attenuated, noise can be reduced.
<Figure 7 Leaf spring bidirectional use>
With reference to FIG. 7, another embodiment of the fuel injection valve of the present invention will be described.
[0028]
FIG. 7 is a sectional view showing only the interlocking members 10a and 10b, the movable iron core 5, the damper plate 8, the cylindrical member 6 and the rod 7 extracted from the fuel injection valve of the present invention.
[0029]
The interlocking member is divided into two parts, a lower interlocking member 10a and an upper interlocking member 10b. The damper plate 8 is inserted into the lower interlocking member 10a, and the upper interlocking member 10b is inserted from above.
[0030]
According to such a configuration, the damper plate 8 functions as a leaf spring when the interlocking members 10a and 10b are displaced downward, and at the same time, the damper plate 8 is functioned as a leaf spring when displaced upward. be able to. By setting the natural period determined by the spring constant of the damper plate 8 and the mass of the interlocking members 10a and 10b to be equal to or close to the period of the repulsive force received by the movable core 5 at the time of the valve-opening collision, The member 22 can act as a dynamic vibration absorber. Therefore, the bouncing suppression effect at the time of valve opening can be further enhanced. Furthermore, the bouncing suppression effect at the time of valve closing can also be acquired.
[0031]
In the present embodiment, since a metal plate spring such as stainless steel is used as the damper plate 8, the temperature dependence of the spring constant is low compared to the case where rubber or the like is used, and it is stable against temperature changes. A bouncing suppression effect is obtained. Furthermore, it is excellent in durability.
<Figure 8 Horseshoe-shaped leaf spring bidirectional use>
Another embodiment of the fuel injection valve of the present invention will be described with reference to FIG.
[0032]
FIG. 8 is a cross-sectional view showing only the interlocking member 10, the movable iron core 5, the damper plate 8, the cylindrical member 6, and the rod 7 extracted from the fuel injection valve of the present invention.
[0033]
The damper plate 8 has a shape having an opening 803. The interlocking member 10 has a shape having a constricted portion 102 near the tip thereof. The damper plate 8 is inserted into the constricted portion 102 of the interlocking member 10 from the opening, and the two are combined.
[0034]
According to such a structure, without dividing the interlocking member 10, the damper plate 8 can function as a leaf spring in both directions when the interlocking member 10 is displaced upward and when the interlocking member 10 is displaced downward. become able to. Therefore, the bouncing suppression effect can be obtained both when the valve is closed and when the valve is opened.
<Fig. 9 Split anchor>
With reference to FIG. 9, another embodiment of the fuel injection valve of the present invention will be described.
[0035]
FIG. 9 is a cross-sectional view showing only the interlocking member 10, the movable iron cores 5a and 5b, the damper plate 8, and the cylindrical member 6 extracted from the fuel injection valve of the present invention.
[0036]
The movable core is divided into an inner movable core 5a and an outer movable core 5b. After the interlocking member 10 is inserted into the outer movable core 5b, the inner movable core 5a is inserted into the outer movable core 5b and fixed.
[0037]
Thereby, the outer movable iron core 5b, the damper plate 8, the cylindrical member 6 and the like can be assembled without inserting the interlocking member 10. Therefore, finishing of the side surface and the top surface of the outer movable iron core 5b can be performed without paying attention to the interference between the tool and the interlocking member 10. Moreover, since the foreign matter generated in connection with the processing can be cleaned without the interlocking member 10, the residual foreign matter after cleaning can be extremely reduced.
<Figure 10 Plating / Surface treatment>
Another embodiment of the fuel injection valve of the present invention will be described with reference to FIG.
[0038]
FIG. 10 is a sectional view showing only the interlocking member 10, the movable iron core 5, the damper plate 8, and the tubular member 6 among the fuel injection valves of the present invention.
[0039]
Plating 26 and 27 are applied to the portion where the movable iron core 5 and the interlocking member 10 are engaged. Further, the plating 28 may be provided on a portion of the movable iron core 5 where the interlocking member 10 slides. Further, a plating 29 may be provided at a portion that collides with the inner iron core 9 of the movable iron core 5.
[0040]
According to this, the movable iron core 5 is not worn by the collision or sliding of the interlocking member 10, and the durability is high. In addition, a stable bouncing suppression effect can be maintained even when the operation is repeated for a long time. The same effect can be obtained by performing surface treatment such as quenching or nitriding instead of plating.
[0041]
1 to 10 show the means that uses the electromagnetic force as means for driving the valve body 4 in the axial direction, but the effect of the present invention is not impaired even if another drive means is used. For example, the present invention can also be applied to a case in which a fuel pressure is used to create a pressure difference above and below the valve body 4 to drive the valve body 4 in the axial direction.
[0042]
1 to 10, the movable range of the valve body 4 in the axial direction is determined by the lower end surface of the inner core 10, but instead of the inner core 10, the movable range of the valve body 4 is set by another stopper member. Needless to say, the effects of the present invention can be obtained even in the case of restriction.
[0043]
【The invention's effect】
According to the present invention, a bouncing suppression mechanism using an additional mass is also provided for a fuel injection valve having a small outer diameter, and valve body bouncing can be suppressed. Thereby, the fuel injection valve excellent in the linearity of the injection amount with respect to the input pulse width can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a fuel injection valve of the present invention.
FIG. 2 is a schematic diagram showing a valve opening operation of an embodiment of the fuel injection valve of the present invention.
FIG. 3 is a graph showing an input pulse, a current, and a valve body displacement of an embodiment of the fuel injection valve of the present invention.
FIG. 4 is a graph showing a relationship between an input pulse and an injection amount in one embodiment of the fuel injection valve of the present invention.
FIG. 5 is a cross-sectional view showing another embodiment of the fuel injection valve of the present invention.
FIG. 6 is a cross-sectional view showing another embodiment of the fuel injection valve of the present invention.
FIG. 7 is a cross-sectional view showing another embodiment of the fuel injection valve of the present invention.
FIG. 8 is a cross-sectional view showing another embodiment of the fuel injection valve of the present invention.
FIG. 9 is a sectional view showing another embodiment of the fuel injection valve of the present invention.
FIG. 10 is a cross-sectional view showing another embodiment of the fuel injection valve of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Orifice plate, 2 ... Fuel injection hole, 3 ... Valve seat, 4 ... Valve body, 5 ... Movable iron core, 6 ... Cylindrical member, 7 ... Rod, 8 ... Damper plate, 9 ... Inner iron core, 10 ... Interlocking member 11 ... Nozzle holder, 12 ... Swirler, 13 ... Guide plate, 14 ... Nozzle housing, 15 ... Ring, 16 ... Plate housing, 17 ... Outer iron core, 18 ... Coil, 19 ... Spring pin, 20 ... Spring, 21 ... Fuel Supply port.

Claims (6)

A fuel injection hole, a valve seat disposed in the vicinity of the fuel injection hole, a valve body that opens and closes a fuel passage by contact with and separation from the valve seat, and a spring that presses the valve body against the valve seat; In the fuel injection valve comprising: an interlocking member separate from the valve body provided between the valve body and the spring; and drive means for driving the valve body,
The fuel injection valve according to claim 1, wherein the valve body is provided with a movable range restricting portion that restricts a movable range of the interlocking member in a direction away from the valve body. The fuel injection valve according to claim 1, wherein
As the drive means, a movable iron core provided on the valve body side, and an inner iron core that attracts the movable iron core by electromagnetic force,
A large-diameter portion is provided at an end of the interlocking member on the movable iron core side, and the movable range restricting portion is formed by a stepped portion that is provided on an inner diameter portion of the movable core and engages with the large-diameter portion. Fuel injection valve.   2. The fuel injection valve according to claim 1, wherein an elastic member is provided in the movable range restricting portion.   2. The fuel injection valve according to claim 1, wherein a space for confining fuel is formed in the movable range restricting portion by the interlocking member and the valve body. 3. The fuel injection valve according to claim 1, wherein
An elastic member constituted by a leaf spring is provided in the valve body,
An engagement portion that engages with the valve seat side surface of the leaf spring when moved in a direction away from the valve body, and the leaf spring when moved in a direction opposite to the direction. An engaging portion that engages with a surface on the opposite side of the surface,
A fuel injection valve, wherein a movable range of the said valve body side of the movable range and the interlocking member in the direction away from the valve body of the interlocking member is regulated resiliently by the plate spring.   The fuel injection valve according to any one of claims 1 to 5, wherein a wear-resistant treatment is applied to a collision part or a sliding part between the interlocking member and the valve body.

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