CN109072833B - Fuel injection valve - Google Patents
Fuel injection valve Download PDFInfo
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- CN109072833B CN109072833B CN201680085389.1A CN201680085389A CN109072833B CN 109072833 B CN109072833 B CN 109072833B CN 201680085389 A CN201680085389 A CN 201680085389A CN 109072833 B CN109072833 B CN 109072833B
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- armature
- fuel injection
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- 239000000446 fuel Substances 0.000 title claims abstract description 90
- 238000002347 injection Methods 0.000 title claims abstract description 81
- 239000007924 injection Substances 0.000 title claims abstract description 81
- 230000004907 flux Effects 0.000 claims abstract description 69
- 230000002093 peripheral effect Effects 0.000 claims abstract description 24
- 239000000696 magnetic material Substances 0.000 claims abstract description 8
- 229920006395 saturated elastomer Polymers 0.000 claims description 14
- 230000009467 reduction Effects 0.000 claims description 9
- 238000000034 method Methods 0.000 claims 1
- 238000002485 combustion reaction Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 8
- 230000005389 magnetism Effects 0.000 description 7
- 238000011144 upstream manufacturing Methods 0.000 description 6
- 238000006073 displacement reaction Methods 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M51/00—Fuel-injection apparatus characterised by being operated electrically
- F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
A magnetic fuel injection valve (100) comprises a holder (7) and a housing (8), wherein the holder (7) is provided on the outer peripheral side of a core (6) and an armature (5) and is formed of a magnetic material, and the housing (8) is provided on the outer peripheral side of the holder (7). An electromagnetic path from the housing (8) to the core (6) via the holder (7) has: a magnetic path (A) from the holder (7) to the core (6) via the armature (5); a magnetic circuit (B) directly reaching the core (6) from the holder (7); and a common magnetic path (C) reaching the magnetic path (A) and the magnetic path (B). The holder (7) or the case (8) serving as the common magnetic path (C) is provided with a magnetic path having a cross-sectional area S2The magnetic reducing portion of (1). By making S2A magnetic path cross-sectional area S smaller than the minimum magnetic path cross-sectional area S in the magnetic path (A, B)A、SBTotal area S of1Small, the magnetic flux is adjusted, thereby suppressing the electromagnetic force deviation between products.
Description
Technical Field
The present invention relates to an electromagnetic fuel injection valve used in an internal combustion engine or the like.
Background
A conventional fuel injection valve has a structure including a magnetic circuit including a cover, a housing, a movable member, and a core. The magnetic flux generated by the coil passes through the nonmagnetic sleeve from the inner periphery of the case, enters the side surface of the movable element, and passes through the air gap from the end surface of the movable element, and enters the end surface of the core.
In such a configuration, the mover and the core portion are disposed in the non-magnetic sleeve, and an electromagnetic attraction force is generated to the mover (for example, see patent document 1).
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2005-282576
Disclosure of Invention
Technical problem to be solved by the invention
As shown in fig. 8, in the conventional fuel injection valve, a movable element 101 (armature) and a core 102 are disposed to face each other with an air gap 103 interposed therebetween. Further, a magnetic flux is generated in the magnetic circuit 103a passing through the air gap 103, and an electromagnetic attractive force is generated in a tension direction of the above-described magnetic flux. However, there are shape deviations of the movable element 101 and the core 102 and inclination deviations of the tangential plane depending on the arrangement of the movable element 101 and the core 102 between products. Further, due to these variations, the magnetic resistance of the air gap 103 changes, and the magnetic flux generated in the magnetic circuit 103a passing through the air gap 103 changes.
In the conventional fuel injection valve, the sleeve 104 made of a nonmagnetic material is disposed on the outer peripheral side of the air gap 103 and is internally connected to the housing 105 (outer case). Therefore, the magnetic body constituting the magnetic path is not disposed on the outer peripheral side of the air gap 103.
Therefore, a leakage magnetic flux is generated in leakage magnetic path 104a that bypasses air gap 103 and reaches the side surface of core 102 from the side surface of movable element 101.
The leakage magnetic flux generated in the leakage magnetic path 104a has a component extending obliquely from the outer peripheral surface of the movable element 101, and therefore affects the electromagnetic attractive force.
In the fuel injection valve of the conventional structure, the magnetic resistance of the air gap changes according to the deviation of the shapes of the movable element 101 and the core 102 and the deviation of the inclination angle therebetween. Therefore, there is a problem that a deviation is also generated in the magnetic flux passing through the magnetic circuit 103a and the leakage magnetic circuit 104a, and the deviation of the electromagnetic attractive force between products becomes large.
Here, the fuel injection valve that supplies the battery voltage to supply the current to the coil needs to ensure the valve opening operation even in a state where the battery voltage is low at the time of low-temperature start of the internal combustion engine.
In a conventional general fuel injection valve, at a low temperature at the initial stage of operation of the internal combustion engine, for example, when the coil impedance is 12 Ω and the battery voltage is 6V, a small current of about 0.5A is applied. Further, at the start of the operation, the needle valve integrated with the movable element 101 is in a valve-closed state, and the air gap 103 between the movable element 101 and the core 102 is increased, so that a relatively small electromagnetic attractive force is generated.
On the other hand, in the rated state of the internal combustion engine, a voltage of about 12V is supplied from the generator, and therefore, a large current of about 1A flows. Further, the needle valve is in the open state, and the air gap 103 is small, so that a relatively large electromagnetic attractive force is generated.
In order to ensure the operation at low temperature, if the relative area of the movable element 101 is increased to secure the electromagnetic attraction force, the electromagnetic attraction force in the rated state becomes excessive, and a response delay occurs when switching from the valve opening to the valve closing, which causes a problem that the precision of the minute injection amount is lowered.
As described above, when the variation in the electromagnetic attraction force of the fuel injection valve between products is large, the injection amount of the fuel changes, and there is a problem in that the accuracy of the air-fuel ratio of the internal combustion engine decreases. Further, if the response delay at the time of valve closing is large, the variation in the minute injection amount between products becomes large, and there is a problem that the accuracy of the air-fuel ratio at the time of light load in the internal combustion engine is lowered.
The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the accuracy of the injection amount by suppressing variation in the electromagnetic attraction force of the fuel injection valve.
Technical scheme for solving technical problem
The fuel injection valve of the present invention includes: an armature integrally provided with a valve element of the magnetic fuel injection valve and connected to and separated from the core portion by an electromagnetic attraction force; and a holder provided on an outer peripheral side of the core and the armature, the holder being formed of a magnetic material, and an electromagnetic path extending from the holder to the core includes: a first magnetic circuit extending from the holder to the core portion via the armature; a second magnetic circuit directly reaching the core from the holder; and a common magnetic path reaching the first magnetic path and the second magnetic path, wherein the common magnetic path of the holder is provided with a magnetically reduced portion that adjusts a magnetic flux passing through the first magnetic path, and a magnetic path cross-sectional area of the magnetically reduced portion is smaller than a total area of a minimum magnetic path cross-sectional area of the first magnetic path and a minimum magnetic path cross-sectional area of the second magnetic path.
Further, a fuel injection valve of the present invention includes: an armature integrally provided with a valve element of the magnetic fuel injection valve and connected to and separated from the core portion by an electromagnetic attraction force; a holder provided on the outer peripheral sides of the core and the armature and formed of a magnetic material; and a housing provided on an outer peripheral side of the holder, wherein an electromagnetic path extending from the housing to the core through the holder includes: a first magnetic circuit extending from the holder to the core portion via the armature; a second magnetic circuit directly reaching the core from the holder; and a common magnetic path reaching the first magnetic path and the second magnetic path, wherein the common magnetic path of the case is provided with a magnetic reducing portion for adjusting a magnetic flux passing through the first magnetic path, and a magnetic path cross-sectional area of the magnetic reducing portion is smaller than a total area of a minimum magnetic path cross-sectional area of the first magnetic path and a minimum magnetic path cross-sectional area of the second magnetic path.
Effects of the invention
According to the fuel injection valve of the present invention, the holder formed of the magnetic material, which serves as the magnetic circuit constituting portion, is disposed on the outer peripheral side of the core portion and the armature. Further, the magnetic constriction is formed in a common magnetic path of the holder or the housing, which reaches the first magnetic path and the second magnetic path. Further, by controlling the cross-sectional area of the magnetic reducing portion, the magnetic flux passing through the first magnetic circuit is adjusted, and thus variation in electromagnetic attraction between products can be suppressed.
Objects, features, aspects and effects of the present invention other than those described above will become more apparent from the following detailed description of the present invention with reference to the accompanying drawings.
Drawings
Fig. 1 is a side sectional view showing a fuel injection valve according to embodiment 1 of the present invention.
Fig. 2 is a main portion cross-sectional view of a magnetic circuit constituting portion of the fuel injection valve of embodiment 1 when the valve is opened, in which fig. 2 (a) is a view showing a magnetic circuit and fig. 2 (b) is a view showing a magnetic circuit cross-sectional area of a main portion of the magnetic circuit.
Fig. 3 is a diagram necessary for the description of embodiment 1, in which fig. 3 (a) is a diagram showing a magnetic circuit of a fuel injection valve as a comparative example, and fig. 3 (b) is a circuit diagram showing a magnetic circuit of a fuel injection valve of embodiment 1.
Fig. 4 is a diagram showing magnetomotive force dependence of the magnetic flux of the fuel injection valve according to embodiment 1.
Fig. 5 is a side sectional view showing a fuel injection valve according to embodiment 2 of the present invention.
Fig. 6 is a partial cross-sectional view of a magnetic circuit constituting part of the fuel injection valve according to embodiment 2, in which fig. 6 (a) is a view showing a state when the valve is opened, and fig. 6 (b) is a view showing a state when the valve is closed.
Fig. 7 is a side sectional view showing a fuel injection valve according to embodiment 3 of the present invention.
Fig. 8 is a sectional view of a magnetic circuit component of a conventional fuel injection valve.
Detailed Description
Embodiment mode 1
The structure of a fuel injection valve 100 according to embodiment 1 of the present invention will be described with reference to fig. 1 to 4.
Fig. 1 is a side sectional view showing the overall configuration of a fuel injection valve 100 according to embodiment 1 of the present invention. As shown in fig. 1, the outer shape of the fuel injection valve 100 is formed by the resin mold 1, and a passage for fuel is formed in a direction from top to bottom of the paper. A valve seat 2 is disposed in the vicinity of the injection port in the lower portion of the fuel injection valve 100, and the valve seat 2 has a conical seat surface 2 a. Further, the fuel injection amount is controlled in accordance with the detached state of the valve element 3 from the valve seat surface 2 a.
The valve body 3 is fixed to an armature 5 (movable member) movable by electromagnetic control via a needle valve 4. An armature end face 5a is formed at a position of the armature 5 on the upstream side of the fuel passage. A core portion 6 serving as a base portion of the fuel flow path (pipe) is disposed upstream of the armature 5 in the fuel flow path. A core end surface 6a is formed on a downstream end surface of the core 6, and the core end surface 6a faces the armature end surface 5 a.
The gap between the interfacing split faces of the armature 5 and the core 6 forms an air gap. Further, a holder 7 formed of a magnetic material is disposed on the outer peripheral side of the contact and separation surface of the armature 5 and the core 6. The holder 7 constitutes a component of the magnetic circuit. Further, the core 6 is pressed into the holder 7, and the two are joined.
The valve seat 2 is held in the holder 7 on the downstream side of the fuel passage.
Further, a housing 8 is disposed on the outer peripheral side of the holder 7, and the housing 8 constitutes a component of the magnetic circuit. A coil 9 is disposed between the case 8 and the core 6, and the case 8 and the core 6 are joined via a cover 10.
Further, a rod 11 is fixed to the inner diameter of the core 6, and a spring 12 is disposed between the rod 11 and the needle 4, and the spring 12 applies an axial load to the needle 4.
The fuel injection valve 100 is connected to an upstream fuel pipe via a rubber ring 13 in a fuel-tight manner. The fuel passes through a filter 14 disposed at the fuel supply end of the core 6 and is supplied to the interior of the fuel injection valve 100. The supplied fuel passes through the fuel flow paths of the respective components, reaches the contact portion between the valve body 3 and the valve seat surface 2a, is in a valve-opened state, and is injected through the orifice 15a of the orifice plate 15.
Next, the operation of opening the valve at the beginning of the operation of the fuel injection valve 100 will be described.
In the fuel injection valve 100, when a voltage between two terminals 16 (only one terminal is shown in fig. 1) is turned on, a current flows through the coil 9 connected to the terminals 16. Then, the magnetic flux flows back in a magnetic circuit mainly composed of the core 6, the cover 10, the case 8, the holder 7, the armature 5, and the magnetic material of the core 6 by the magnetic field generated by the energization.
Between the armature 5 and the core 6, the magnetic flux passes in a direction substantially perpendicular to the armature end face 5a and the core end face 6 a. Further, the tension in the direction of the magnetic flux acts to generate an electromagnetic attraction force toward the core 6 in the armature 5, which is a movable component. If the electromagnetic attraction force is larger than the load of the spring 12, the needle valve 4 starts to be displaced. The displacement of the needle valve 4 is completed at a position where the armature end surface 5a contacts the core end surface 6a, and the valve is opened, and a gap of about 40 to 60 μm is formed between the valve body 3 and the valve seat surface 2 a. The fuel is injected from the orifice 15a to the outside through the above gap.
Next, a valve closing operation of the fuel injection valve 100 will be described.
When the voltage between the two terminals 16 is cut off, the current of the coil 9 is interrupted. When the current is interrupted, the electromagnetic attraction force acting on the armature 5 decreases as the magnetic flux decreases, and when the electromagnetic attraction force becomes smaller than the load of the spring 12 after a predetermined time has elapsed, the needle valve 4 starts to be displaced. The displacement trajectory of the needle valve 4 in the time after the voltage cut is a parabolic displacement after a predetermined time without displacement has elapsed, and the displacement is completed after the valve element 3 comes into contact with the valve seat surface 2 a. The fuel injection is completed with the end of the shift.
Next, fig. 2 shows a main part cross-sectional view of the magnetic circuit component when the valve is opened, and the magnetic circuit and the cross-sectional area thereof will be described. Fig. 2 (a) shows the flow of magnetic flux (electromagnetic path) in the fuel injection valve 100 in the vicinity of the air gap between the armature end face 5a and the core end face 6a, and fig. 2 (b) shows the magnetic path cross-sectional area of the main portions of the magnetic circuit.
As shown in fig. 2 (a), the magnetic flux in the case 8 reaches the core 6, but the electromagnetic path thereof is constituted by a common magnetic path C that reaches the lower end of the armature 5 from a press-fitting portion (joint portion) of the case 8 and the holder 7 through the axial direction of the holder 7, a magnetic path a (corresponding to a first magnetic path) that branches from the common magnetic path C and reaches the core 6 via the armature 5, and a magnetic path B (corresponding to a second magnetic path) that reaches the core 6 directly from the holder 7. In fig. 2 (a), the magnetic path a is indicated by a short dashed line, the magnetic path B is indicated by a long dashed line, and the common magnetic path C is indicated by an open line.
Fig. 2 (b) is a sectional view of the armature 5, the core 6, and the holder 7 taken from fig. 2 (a). In fig. 2 (b), a plurality of components having different magnetic path cross-sectional areas of the holder 7 are formed, and these components are arranged and formed in the first cylindrical portion 7a, the second cylindrical portion 7b, the third cylindrical portion 7c, and the fourth cylindrical portion 7d in this order from the downstream side to the upstream side of the flow path.
The first cylindrical portion 7a of the holder 7 is a portion that is press-fitted into the thick wall of the housing 8, and constitutes the common magnetic path C.
Next, the second cylindrical portion 7b formed in the axial direction is a portion that constitutes the common magnetic path C from the first cylindrical portion 7a to the joint lower end of the holder 7 and the armature 5. The second cylindrical portion 7b corresponds to a magnetic reduction portion that constitutes a feature of the present invention. The cross-sectional area of the second cylindrical portion 7b as the magnetic reducing portion is formed to be smallest in the magnetic circuit of the fuel injection valve 100. That is, the cross-sectional area of the second cylindrical portion 7b corresponds to the magnetic path cross-sectional area S of the magnetically constricted portion2。
Further, for example, the second cylindrical portion 7b can be formed by cutting the holder 7, and the accuracy of adjusting the magnetic flux of the magnetic reducing portion can be ensured by realizing an arbitrary dimensional accuracy.
Next, the third cylindrical portion 7c is formed on the outer peripheral side of the air gap which is a gap portion between the contact and separation surfaces of the armature 5 and the core portion 6, and serves as a portion of the magnetic circuit B. The cross-sectional area of the third cylindrical portion 7c is smallest in the holder 7 and corresponds to the smallest magnetic path cross-sectional area S in the magnetic path BB。
Next, the fourth cylindrical portion 7d is a portion that is press-fitted into the core 6.
Here, the cross-sectional area of the magnetic path at the joint surface of the armature 5 and the core 6 is represented as SA. Further, the magnetic circuit of the fuel injection valve 100 of the present invention is formed to satisfy SA+SB＝S1And S is1＞S2The size of (c).
Next, the magnetic flux passing through each magnetic circuit will be described.
As shown in fig. 2 (a), in the common magnetic path C, the outer periphery of the holder 7 is press-fitted into and in contact with the inner periphery of the housing 8, and therefore, the magnetic flux penetrates the first cylindrical portion 7a from the housing 8 with almost no magnetic loss.
When the magnetic flux passing through the first cylindrical portion 7a is equal to or greater than a value corresponding to the magnetic path cross-sectional area of the second cylindrical portion 7b, the magnetically reduced portion of the second cylindrical portion 7b is magnetically saturated, and the magnetic flux passing through the second cylindrical portion 7b on the upper side in the axial direction is adjusted (limited) to a predetermined value.
The magnetic flux adjusted in the magnetically constricted portion of the holder 7 is branched into the magnetic path a and the magnetic path B, and travels upward in the axial direction. At this time, since the third cylindrical portion 7c constituting the magnetic circuit B is formed to have the smallest cross-sectional area in the magnetic circuit, it is in a saturated state, and the surplus magnetic flux not flowing through the magnetic circuit B proceeds toward the magnetic circuit a. The magnetic path a and the magnetic path B reach the core 6 and merge.
The magnetic circuit of the fuel injection valve 100 will be described in detail.
In a rated operation state of the internal combustion engine, when a current of 1A is passed through a coil having a winding number of 340 turns, a relatively large magnetomotive force of 340A is generated in the magnetic circuit, and the second cylindrical portion 7b of the holder 7 corresponding to the magnetism reducing portion is in a magnetic saturation state.
The number of magnetic fluxes flowing back in the magnetic circuit is limited to the number of saturated magnetic fluxes at the minimum magnetic path cross-sectional area portion of the common magnetic path C, i.e., the magnetically reduced portion (second cylindrical portion 7b) of the holder 7.
A part of the magnetic flux of the common magnetic path C branches and passes through the magnetic path B to reach the core 6. That is, a part of the magnetic flux passing through the second cylindrical portion 7b of the holder 7 enters the core 6 through the third cylindrical portion 7c and the fourth cylindrical portion 7 d.
Then, the surplus magnetic flux branched from the common magnetic path C passes through the magnetic path a to reach the core 6. That is, the remaining magnetic flux that passes through the second cylindrical portion 7B of the holder 7 but does not enter the magnetic circuit B enters the outer peripheral surface of the armature 5 from the inner peripheral surface of the second cylindrical portion 7B, passes through the inside of the armature 5 in the axial direction, and enters the core 6 from the core end surface 6a via the air gap from the armature end surface 5 a.
Here, for example, the smallest cross-sectional area S of the magnetic path BBThe thickness of the third cylindrical portion 7c of the holder 7 is set to about 0.2 mm. The magnetic path cross-sectional area SBA magnetic path cross section S of the magnetic reduced portion formed as the second cylindrical portion 7b2Is greater than or equal to 13 or less. The third cylindrical portion 7c of the holder 7 is magnetically saturated in the same manner as the magnetic reduction portion. Thereby, the magnetic flux passing through the magnetic circuit a can be adjusted by the magnetic reducing portion.
On the other hand, the minimum magnetic path cross-sectional area S of the magnetic path AACorresponding to the area of the end faces of the armature 5 and the core 6 in the air gap portion. Due to S2Is the minimum cross-sectional area in the magnetic circuit, and therefore, the total cross-sectional area S of the air gap between the magnetic circuit A and the magnetic circuit B1Presence of S1＝SA+SB＞S2The relationship (2) of (c).
Here, for example, by adding S1：S210: the aspect 9 controls the size, so that the effect of suppressing the variation of the electromagnetic attraction force becomes remarkable. At S2Smaller than the above relationship, the electromagnetic attraction is insufficient, and S is2Greater than the above relationship and very close to S1In the case of the value of (3), the dimensional tolerance may reverse the direction, and the effect of suppressing variation in the electromagnetic attractive force may be reduced.
Next, referring to fig. 3, the magnetic circuit of the fuel injection valve of the conventional structure of the comparative example and the magnetic circuit of the fuel injection valve 100 of the present invention are compared. In fig. 3, (a) of fig. 3 is a circuit diagram showing a magnetic circuit of a conventional fuel injection valve of a comparative example, and (b) of fig. 3 is a circuit diagram showing a magnetic circuit of a fuel injection valve 100 according to embodiment 1. The circuit diagram of fig. 3 (a) reflects the structure of the conventional fuel injection valve shown in fig. 8, and it is considered that a magnetic path 103a extending from the movable element 101 (armature) to the core 102 in fig. 8 corresponds to the magnetic path a of fig. 2 (a), and a leakage magnetic path 104a occurring in the sleeve 104 corresponds to the magnetic path B of fig. 2 (B). In FIG. 3 (a), the symbol B0Showing leakage magnetic path 104 a.
In the circuit diagram of fig. 3, the magnetomotive force of the coil is denoted by E, the reluctance of the magnetic circuit a is denoted by RA, and the reluctance of the magnetic circuit a is denoted by RB0Indicating the leakage path B0The magnetic resistance of (1). The electromotive force E of the magnetic circuit corresponds to the DC voltage of the electric circuit, the magnetic resistances RA, RB0Corresponding to the resistance. In addition, the magnetic flux flowing in the magnetic circuit corresponds to a current.
As shown in fig. 3In the conventional magnetic circuit, as shown in (a), a leakage magnetic path B is generated in parallel with the magnetic path a0Magnetic flux PhiA passing through magnetic path A and leakage magnetic path B passing through magnetic path A0Magnetic flux of phi B0Will depend on the magnetomotive force E and the magnetic resistances RA, RB of the coil0And change in phi A and phi B0All have an influence on the electromagnetic attraction. In addition, the magnetic flux Φ passing through the common magnetic path C0Is phi with unrestricted magnetic flux0total。
As shown in fig. 3 (B), in the magnetic circuit of the present invention, the magnetic path a and the magnetic path B are branched from the common magnetic path C and formed in parallel, and the magnetic flux limiter 70B corresponding to the magnetic flux narrowing portion is connected to the common magnetic path C so as to be arranged in series with the magnetic path a and the magnetic path B. Further, a magnetic flux limiter 70c is connected to a portion of the magnetic circuit B located in the air gap portion.
That is, in the magnetic circuit of the present invention, when the magnetomotive force E at the time of opening the valve in the rated operation state is relatively large, the magnetic path B becomes the magnetic flux limiter 70C (current limiter of the electric circuit) due to the saturation of the magnetic flux, and the magnetic narrowed portion (magnetic flux limiter 70B) of the common magnetic path C also becomes the magnetic flux limiter due to the saturation of the magnetic flux. The magnetic flux Φ a passing through the air gap of the magnetic circuit a is determined from Φ total — Φ B. At this time, the number of saturation fluxes of Φ B and Φ total is determined by the material and the cross-sectional area of the holder 7, and is not affected by the change in the magnetomotive force E, and therefore Φ a is also stably determined.
This can suppress variation in electromagnetic attraction between products. Thus, in the fuel injection valve 100 of the present invention, the variation in electromagnetic attraction force can be reduced to improve the injection amount accuracy.
Next, the magnetomotive force E dependence of the magnetic flux Φ of the fuel injection valve 100 according to the present invention will be described with reference to fig. 4. As illustrated in fig. 4, the magnetic flux Φ with respect to the conventional structure0The monotonically increasing trajectory of a is such that, in the fuel injection valve 100 of the present invention, since the second cylindrical portion 7b (magnetic flux limiter 70b) of the holder 7 as the magnetic reducing portion is saturated, the magnetic flux Φ a becomes a constant value Φ max within a magnetomotive force Emax (a range indicated by symbol Emax in fig. 4) of a predetermined value or more, and the Φ max is equal to the conventional value Φ maxValue phi0max is reduced compared to.
On the other hand, in the magnetomotive force Emin in which the magnetically reduced portion of the holder 7 is not saturated, the magnetic flux Φ0The magnetic flux Φ min of a and Φ a is the same value as in the related art.
As shown in fig. 4, the magnetic flux limiter 70c formed by the third cylindrical portion 7c of the holder 7 is not saturated in the range from the magnetomotive force E of 0 to E1 in the saturated state, is saturated when the magnetomotive force E reaches E1, and has a constant value Φ B in the range from E2 where the magnetomotive force is equal to or greater than E1.
Thus, for example, while the electromagnetic attraction force in the valve-closed state at the time of low-temperature start is substantially maintained, the electromagnetic force in the valve-open state at the time of rated operation can be reduced, and the response delay at the time of switching from valve-open to valve-closed can be improved. Therefore, in the fuel injection valve 100 of the present invention, the precision of the minute injection amount can be improved.
In the conventional fuel injection valve shown in fig. 8, as described above, in the leakage magnetic path 104a extending from the outer peripheral surface of the released movable element 101 (armature) to the outer peripheral surface of the core 102, a leakage magnetic flux in an oblique direction is generated from the outer peripheral surface of the movable element 101, and the leakage magnetic flux affects the electromagnetic attraction force that moves the movable element 101.
However, in the fuel injection valve 100 of the present invention, the inner peripheral surface of the holder 7 faces the entire outer peripheral surface of the armature 5 with a slight gap. Further, since the holder 7 is a magnetic body, magnetic flux flows in and out in a direction perpendicular to the outer peripheral surface of the armature 5, that is, in a radial direction.
Therefore, in the fuel injection valve 100 of the present invention, the occurrence of the leakage magnetic flux entering obliquely to the axis as in the conventional case can be suppressed, and the electromagnetic attraction force that moves the armature 5 can be prevented from being affected. By improving the deviation of the electromagnetic attraction force, the fuel injection accuracy can be improved.
As described above, the fuel injection valve 100 according to embodiment 1 of the present invention can suppress variation in electromagnetic force, can reduce electromagnetic attraction force in the valve-opened state, and can contribute to improvement in the air-fuel ratio accuracy of the internal combustion engine.
Next, embodiment 2 of the present invention will be described with reference to fig. 5 and 6. Fig. 5 is a side sectional view of the fuel injection valve 100 according to embodiment 2, and fig. 6 is a main part sectional view of a magnetic circuit component, in which fig. 6 (a) shows a state in which the armature 5 and the core 6 are in contact when the valve is opened, and fig. 6 (b) shows a state in which the air gap 50 is formed between the armature 5 and the core 6 when the valve is closed.
In embodiment 1 described above, the second cylindrical portion 7b serving as the magnetically constricted portion of the holder 7 is formed to have the same dimension in the axial direction, and the magnetic path cross-sectional area S in the second cylindrical portion 7b2Are the same value. However, in embodiment 2, the portion of the holder 71 facing the armature 5, which corresponds to the magnetically constricted portion of the holder 71, is formed so that the outer surface portion thereof is tapered, and the cross-sectional area S of the magnetic path appears as the armature 5 moves in the axial direction2A change occurs.
As shown in fig. 5, the holder 71 is characterized in that the surface facing the armature 5 has a shape of a magnetically reduced portion constituting the common magnetic path C, and the outer surface of the magnetically reduced portion is inclined so as to form a tapered shape having a cross-sectional area of the magnetic path increasing toward the downstream side of the magnetic path. The magnetic flux reduction portion is located at a branch point that branches from the common magnetic path C into the magnetic path a and the magnetic path B. Further, the magnetic path cross-sectional area S in the valve-opened state in which the core 6 is in contact with the armature 52(open) is formed to have a magnetic path cross-sectional area S in a valve-closed state separated from the core 6 and the armature 52(close) is small. That is, the magnetic reducing portion is formed in the S in fig. 6 (a) and 6 (b)2(open)、S2The position of the line indicated by (close) is a hollow conical shape perpendicular to the tapered surface, with the vicinity of the downstream end surface of the armature 5 facing the holder 71 being the starting point.
In the open state of the fuel injection valve 100, the armature 5 is lifted up to the position of contact with the core 6 toward the upstream side, and therefore the magnetically constricted portion corresponds to the symbol S of the holder 71 of fig. 6 (a)2(open) moiety. In the valve-closed state, the needle valve 4 is pushed by the spring 12 to the downstream side to a position where the valve body 3 contacts the valve seat surface 2a, and therefore, the magnetic constriction portion corresponds to that of the holder 71 shown in fig. 6 (b)Symbol S2(close) part(s). The outer peripheral surface of the holder 71 is tapered so as to decrease in diameter toward the upstream side of the fuel path, and therefore, S exists2(open)＜S2(close) relationship.
In the fuel injection valve 100 according to embodiment 1, the number of magnetic fluxes restricted by the magnetism reducing portion does not change depending on the position of the armature 5, but in the fuel injection valve 100 according to embodiment 2, the number of magnetic fluxes in the valve-open state at the time of rated operation of the magnetism reducing portion is restricted to be smaller than the number of magnetic fluxes in the valve-closed state at the time of the initial operation. That is, the number of magnetic fluxes Φ total when the magnetomotive force is Emax is controlled to be smaller than the number of magnetic fluxes Φ total when the magnetomotive force is Emin. This reduces the electromagnetic attraction force in the valve-open state during the rated operation of the fuel injection valve 100.
As described above, the fuel injection valve 100 according to embodiment 2 of the present invention can further reduce the electromagnetic attraction force in the valve-opened state as compared with the fuel injection valve 100 according to embodiment 1, and therefore can improve the accuracy of the minute injection amount and can further improve the air-fuel ratio accuracy of the internal combustion engine.
It goes without saying that the dimensional accuracy can be adjusted within an allowable range by forming the tapered surface of the magnetically reduced portion of the holder 71 by cutting.
Next, embodiment 3 of the present invention will be described with reference to fig. 7. Fig. 7 is a side sectional view of fuel injection valve 100 according to embodiment 3. While the magnetic reducing portion is formed in the holder 7 or 71 constituting the magnetic circuit in embodiment 1 or embodiment 2, the magnetic reducing portion 8a is formed in the housing 8 in embodiment 3. The housing 8 and the holder 7 together constitute a common magnetic circuit C.
Here, in the magnetism reducing portion 8a, the number of magnetic fluxes flowing back in the magnetic circuit is limited. However, in the magnetic reducing portion 8a, when another magnetic substance approaches, a path of magnetic flux due to magnetic leakage may be generated. Further, the number of magnetic fluxes penetrating the magnetic reducing portion 8a may vary due to variations in the distance between another magnetic material and the magnetic reducing portion 8 a.
Therefore, in embodiment 3, the magnetism reducing portion 8a is formed at the axial center portion of the large diameter portion of the housing 8, where the spatial distance from the other magnetic body is increased. By forming the magnetism reducing portion 8a in such a configuration, it is possible to reduce the above-described magnetic leakage as much as possible, and it is possible to suppress variation in the number of magnetic fluxes passing through the magnetism reducing portion 8a and suppress variation in the electromagnetic attractive force.
Here, it is needless to say that the magnetic reduced portion 8a of the case 8 can be formed by, for example, cutting.
In the present invention, the embodiments can be freely combined, or can be appropriately modified or omitted within the scope of the invention.
Claims (8)
1. A fuel injection valve is characterized in that,
the method comprises the following steps: an armature integrally provided with a valve element of the magnetic fuel injection valve and connected to and separated from the core portion by an electromagnetic attraction force; and a holder provided on outer peripheral sides of the core and the armature and formed of a magnetic material,
the electromagnetic path from the holder to the core has: a first magnetic circuit from the holder to the core via the armature; a second magnetic circuit directly reaching the core from the holder; and a common magnetic circuit reaching the first magnetic circuit and the second magnetic circuit,
a magnetic reduction portion that adjusts a magnetic flux passing through the first magnetic circuit is provided in the common magnetic circuit of the holder,
the magnetic path cross-sectional area of the magnetic constricted portion is smaller than the total area of the minimum magnetic path cross-sectional area of the first magnetic path and the minimum magnetic path cross-sectional area of the second magnetic path.
2. The fuel injection valve according to claim 1,
the magnetically reduced portion is located at a branch point between the common magnetic path and the first and second magnetic paths, and a magnetic path cross-sectional area of the magnetically reduced portion in an open valve state in which the core portion is in contact with the armature is formed smaller than a magnetic path cross-sectional area of the magnetically reduced portion in a closed valve state in which the core portion is separated from the armature.
3. The fuel injection valve according to claim 1 or 2,
the cross-sectional area of the second magnetic circuit is set to: the magnetic valve is magnetically saturated in an open valve state in which the core portion and the armature are in contact with each other.
4. The fuel injection valve according to claim 1 or 2,
the cross-sectional area of the magnetic reduction part is set as follows: the magnetic valve is magnetically saturated in an open valve state in which the core portion and the armature are in contact with each other.
5. The fuel injection valve according to claim 3,
the cross-sectional area of the magnetic reduction part is set as follows: the magnetic valve is magnetically saturated in an open valve state in which the core portion and the armature are in contact with each other.
6. A fuel injection valve characterized by comprising:
an armature integrally provided with a valve element of the magnetic fuel injection valve and connected to and separated from the core portion by an electromagnetic attraction force;
a holder provided on outer peripheral sides of the core and the armature and formed of a magnetic member; and
a housing provided on an outer peripheral side of the holder,
the electromagnetic path from the housing to the core via the holder has: a first magnetic circuit from the holder to the core via the armature; a second magnetic circuit directly reaching the core from the holder; and a common magnetic circuit reaching the first magnetic circuit and the second magnetic circuit,
a magnetic reduction portion is provided in the common magnetic path of the case, the magnetic reduction portion adjusting a magnetic flux passing through the first magnetic path,
the magnetic path cross-sectional area of the magnetic constricted portion is smaller than the total area of the minimum magnetic path cross-sectional area of the first magnetic path and the minimum magnetic path cross-sectional area of the second magnetic path.
7. The fuel injection valve according to claim 6,
the cross-sectional area of the second magnetic circuit is set to: the magnetic valve is magnetically saturated in an open valve state in which the core portion and the armature are in contact with each other.
8. The fuel injection valve according to claim 6 or 7,
the cross-sectional area of the magnetic reduction part is set as follows: the magnetic valve is magnetically saturated in an open valve state in which the core portion and the armature are in contact with each other.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2016/064115 WO2017195319A1 (en) | 2016-05-12 | 2016-05-12 | Fuel injection valve |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109072833A CN109072833A (en) | 2018-12-21 |
| CN109072833B true CN109072833B (en) | 2021-04-20 |
Family
ID=60266592
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201680085389.1A Expired - Fee Related CN109072833B (en) | 2016-05-12 | 2016-05-12 | Fuel injection valve |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP6591055B2 (en) |
| CN (1) | CN109072833B (en) |
| PH (1) | PH12018502349A1 (en) |
| WO (1) | WO2017195319A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7135705B2 (en) * | 2018-10-17 | 2022-09-13 | 株式会社デンソー | solenoid valve |
| WO2020084678A1 (en) * | 2018-10-23 | 2020-04-30 | 三菱電機株式会社 | Electromagnetic fuel injection valve |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6032879A (en) * | 1997-01-17 | 2000-03-07 | Hitachi, Ltd. | Fuel injector for use in internal combustion engine |
| EP1078156A1 (en) * | 1998-05-15 | 2001-02-28 | Siemens Automotive Corporation | Slotted housing for fuel injector |
| CN1877111A (en) * | 2005-06-07 | 2006-12-13 | 株式会社电装 | Injection valve and manufacturing method for the same |
| CN101105165A (en) * | 2006-07-13 | 2008-01-16 | 株式会社日立制作所 | Electromagnetic fuel injection valve |
| CN104912709A (en) * | 2014-03-13 | 2015-09-16 | 日立汽车系统株式会社 | Fuel injection valve |
-
2016
- 2016-05-12 JP JP2018516286A patent/JP6591055B2/en not_active Expired - Fee Related
- 2016-05-12 CN CN201680085389.1A patent/CN109072833B/en not_active Expired - Fee Related
- 2016-05-12 WO PCT/JP2016/064115 patent/WO2017195319A1/en active Application Filing
-
2018
- 2018-11-07 PH PH12018502349A patent/PH12018502349A1/en unknown
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6032879A (en) * | 1997-01-17 | 2000-03-07 | Hitachi, Ltd. | Fuel injector for use in internal combustion engine |
| EP1078156A1 (en) * | 1998-05-15 | 2001-02-28 | Siemens Automotive Corporation | Slotted housing for fuel injector |
| JP2002515562A (en) * | 1998-05-15 | 2002-05-28 | シーメンス オートモーティヴ コーポレイション | Fuel injector slotted housing |
| CN1877111A (en) * | 2005-06-07 | 2006-12-13 | 株式会社电装 | Injection valve and manufacturing method for the same |
| CN101105165A (en) * | 2006-07-13 | 2008-01-16 | 株式会社日立制作所 | Electromagnetic fuel injection valve |
| CN104912709A (en) * | 2014-03-13 | 2015-09-16 | 日立汽车系统株式会社 | Fuel injection valve |
Also Published As
| Publication number | Publication date |
|---|---|
| JP6591055B2 (en) | 2019-10-16 |
| PH12018502349A1 (en) | 2019-09-02 |
| CN109072833A (en) | 2018-12-21 |
| JPWO2017195319A1 (en) | 2018-12-27 |
| WO2017195319A1 (en) | 2017-11-16 |
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