JPH0893592A - Electromagnetic fuel injection valve for internal combustion engine - Google Patents

Abstract

PURPOSE: To facilitate the quantity regulating operation of fuel and to simplify assembling work by reducing a gap between the inner wall of a joint part hole of an injection valve and the outer peripheral wall of an adjusting pipe. CONSTITUTION: A fuel injection valve is opened and closed by separating a valve member from the valve seat of a valve body or bringing them into contact mutually. An electromagnetic actuator moves the valve member to an opening position against the energizing force of an elastic member when electric current is turned on. A level difference 71 to reduce a gap δ1 between the outer peripheral wall of an adjusting pipe 47 and the inner wall of the hole of a joint part 44 into a gap δ2 is formed in the outer peripheral wall of the adjusting pipe 47 which regulates the energizing force of the elastic member and moreover minutely regulates fuel injection quantity. Since the fluctuation of the flow rate of leakage Q2 through the gap δ2 and the flow rate value of the flow rate of leakage Q2 are thereby lessened, the fine adjustment of the flow rate Q1 of the fuel becomes easy. Since the level difference 71 has an axial length not to damage the assembling ability of the adjusting pipe 47, the inserting assembling work of the adjusting pipe 47 into the hole of the joint part 44 becomes easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic fuel injection valve for supplying fuel to an internal combustion engine.

[0002]

2. Description of the Related Art A conventionally known electromagnetic fuel injection valve includes a valve body having an injection hole and a valve seat, and a valve member having an abutting portion and moved in the valve body. There is. The valve member has a closed position where its abutting portion abuts the valve seat to stop the fuel supply to the internal combustion engine, and an open position where the abutting portion is separated from the valve seat to allow the fuel supply to the internal combustion engine. The position is driven by an electromagnetic actuator.

Conventionally, as this type of fuel injection valve, a downstream side for adjusting a fuel injection amount in a gap between a valve seat formed in a valve case and an abutting portion formed in a valve member and abutting the valve seat. There is a fuel metering passage provided with an upstream fuel metering passage for adjusting the injection amount on the upstream side of the downstream fuel metering passage (for example, Japanese Patent Laid-Open No. 63-2393).
59).

In the electromagnetic fuel injection valve of this type,
For example, as shown in FIG. 10, a gap 24 (metering area S1) between the valve seat 16 formed in the valve body 11 and the ridge line 65 of the valve member 20, and the adjusting pipe 47 as shown in FIG. Hole diameter of the orifice 50a (metering area S
Fuel is metered at two locations, 2). As the metering method, the metering area S1 is determined in advance, and while the static injection amount is being measured, an adjusting pipe 47 having an orifice 50a having a different metering area S2, for example, a different hole diameter is appropriately selected. The fuel injection amount is adjusted within a predetermined range.

[0005]

By the way, generally, the injection amount Q of the conventional electromagnetic fuel injection valve is, for example, as shown in FIG.
8 and the flow rate Q ₀ adjusted in the gap 24 between the valve seat 16 and the valve member 20 and the flow rate Q ₁ adjusted in the fuel adjusting section (not shown) below the adjusting pipe 47 shown in FIG. 8, for example. Is determined by. Then, the adjustment order of the injection quantity with respect to the flow rate Q _0, which is adjusted to a flow rate, adjusting pipe having a fuel metering unit of the intended flow rate to Q ₁ of the several flow Q ₁ which is classified to the level of Fine adjustment is performed by selecting 47. Here, a clearance δ1 must be provided between the adjusting pipe 47 and the joint portion 44 in order to ensure the assemblability, and the leakage flow rate Q flowing through this clearance δ1. ₂ varies depending on the component size of the adjusting pipe 47 and the joint portion 44. Therefore, by appropriately selecting the adjusting pipe 47 having orifices with different metering settings and different hole diameters, the adjusting pipes are exchanged until the target injection amount adjustment value is reached, and the flow rate Q
When finely adjusting ₁ , the leak flow rate Q ₂ changes each time the adjusting pipe 47 is selected and replaced. Therefore, the adjusting adjustment of the adjusting pipe 47 is repeated many times.
It was necessary to adjust the flow rate. Therefore, in the conventional example, an O-ring 70 is provided between the adjusting pipe 47 and the joint portion 44 as shown in FIGS.

Even without the O-ring 70, the leakage flow rate Q ₂ can be reduced by setting the component dimensions of the adjusting pipe 47 and the joint portion 44 so that the gap δ1 is made as small as possible before metering. ₁ becomes easier to adjust, but on the other hand, if the gap δ1 between the parts during assembly is too small due to the variation (non-uniformity) in the parts dimensions, the adjusting pipe 47 is assembled and inserted into the hole of the joint portion 44. You may not be able to.

The present invention eliminates the O-ring between the adjusting pipe and the joint, facilitates the fuel metering operation, and facilitates the assembling work, and the electromagnetic fuel injection for an internal combustion engine. The purpose is to provide a valve.

[0008]

An electromagnetic fuel injection valve for an internal combustion engine according to claim 1 of the present invention for achieving the above object, is a valve main body having an injection hole and a valve seat connected to the injection hole, A closed position where the contact portion abuts the valve seat to stop the supply of fuel to the internal combustion engine; and the contact portion is separated from the valve seat to the internal combustion engine. A valve member movably provided between an open position that allows fuel supply, an elastic member that urges the valve member toward the closed position, and a valve member that resists the urging force of the elastic member. And an electromagnetic actuator for moving the elastic member to the open position, adjusting the biasing force of the elastic member, and introducing fuel into the valve body through an internal passage formed therein, and the valve body. And the relative position is determined. And the joint portion having a hole for receiving a flop, characterized in that a throttle for throttling the leakage of fuel between the inner wall of the outer wall and the bore of the adjusting pipe.

The throttle of the electromagnetic fuel injection valve for an internal combustion engine according to a second aspect is characterized in that it is a stepped portion having an uneven shape formed on the outer wall of the adjusting pipe. The throttle of the electromagnetic fuel injection valve for an internal combustion engine according to claim 3 or 4, so that the throttle has a length in the axial direction that does not impair the assembling property of the adjusting pipe in the axial direction, or the fuel reconditioning. It is desirable to have an axial length that suppresses the amount of fuel leakage so that the amount is unnecessary.

[0010]

According to the electromagnetic fuel injection valve for an internal combustion engine of the present invention, a throttle is provided to reduce the gap between the inner wall of the joint hole of the injection valve and the outer peripheral wall of the adjusting pipe. In the present invention, the gap between the adjusting pipe and the joint portion is the gap δ1, but in the present invention, the gap between the adjusting pipe and the joint portion is the gap δ2.
Therefore, as a result, the leakage flow rate Q that leaks from the gap δ2
₂ and the leakage flow rate Q ₂ are reduced, so that the fuel leakage flow rate Q ₂ between the inner wall of the hole of the joint and the outer wall of the adjusting pipe can be suppressed and the fuel can be metered. Make it easier.

Further, since this throttle has an axial length that does not impair the assembling property of the adjusting pipe,
The adjusting pipe can be easily inserted and assembled into the joint hole.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 2 to 5, and in particular to FIG. 2, there is shown a fuel supply system incorporating an electromagnetic fuel injection valve for an internal combustion engine according to an embodiment of the present invention, which is suitable for use in a vehicle, for example. The fuel supply system has a fuel tank 2, and the fuel pumped from the fuel tank 2 by the electromagnetic pump 3 passes through the filter 4 and is sent to the supply path 6 and passes through the supply path 6. It is sent to the pressure control valve 7. Then, the pressurized fuel in the supply passage 6 is sent to the fuel injection valve 1 through the branch pipe 8. The fuel injection valve 1 generally supplies fuel to the intake pipe or cylinder of a spark ignition type internal combustion engine, and gasoline having a relatively low vapor pressure is used as the fuel. The fuel supply pressure by the fuel injection valve 1 is a relatively low pressure of about 250 KPa, and this supply pressure is regulated by the pressure control valve 7 to a constant differential pressure with respect to the pressure of the intake pipe.

The electromagnetic fuel injection valve 1 shown in FIG. 2 has a valve body 11 and a valve case 12, and by bending the tip of the valve case 12 and pressing it against the valve body 11, The valve case 12 is integrally connected. Further, as shown in detail in FIG. 3, the valve body 11 is formed with an injection hole 14 for injecting and supplying the fuel whose metering is completed into the cylinder or the intake pipe, and a truncated cone surface. And a valve seat 16. Returning to FIG.
A guide hole 17 is formed in the valve body 11, and the guide hole 17
The slender needle type valve member 20 housed in is provided with two sliding parts 21 and 22.
In order to smoothly slide the valve member 20, the Nos. 1 and 22 are fitted to the wall surface of the guide hole 17 so as to obtain a gap of several micrometers. The valve member 20 is shown in FIGS.
As shown in FIG. 5, the contact portion 23 provided in the valve member 20 contacts the valve seat 16 to close the injection hole 14, and the supply of fuel to the internal combustion engine is stopped. The closed position and the contact portion 23 are separated from the valve seat 16 by the lift amount H to open the injection hole 14, and allow the fuel to be supplied to the internal combustion engine. It is disposed in the guide hole 17 so as to be movable with respect to the valve body 11 between the open position shown in FIG. And when the valve member 20 occupies the open position shown in FIG.
The valve member 20 is provided with a metering portion defining portion 26 which cooperates therewith to define a fuel metering gap 24 between which the gap 24 has a metering area S1 and which is also metered. Part 26
Is formed by a truncated cone surface. As is clear from FIG. 5, the contact portion 23 is located downstream of the metering portion defining portion 26 with respect to the fuel flowing in the fuel injection valve 1.

Returning to FIG. 2, a disc-shaped stopper 31 is inserted and fixed between the rear end of the valve member 20 and the valve case 12, and a flange 32 provided on the valve member 20 contacts the stopper 31. As a result, the open position of the valve member 20 is determined. The rear end of the valve member 20 is a stopper 3
1 penetrates through 1 and extends into the valve case 12. In the valve case 12, the valve member 20 is driven to drive the valve member 20 in FIG.
An electromagnetic actuator 35 is provided for movement between the closed position shown in FIG. 4 and the open position shown in FIG. The electromagnetic actuator 35 is in a fixed relationship with the armature 36 connected to the rear end of the valve member 20 with respect to the valve case 12, and thus with the stator 37 mounted in a fixed relationship with the valve body 20, The electromagnetic coil 38 is wound around the stator 37. The armature 36 is urged toward the closed position by the return coil spring 39, that is, downward as viewed in FIG. 3, and when an electric current is supplied to the electromagnetic coil 38, an electromagnetic force is generated, and the electromagnetic force causes the armature to be generated. 36 is attracted toward the stator 37 against the biasing force of the coil spring 39, and the flange 3
When 2 abuts on the stopper 31, the valve member 20 occupies the open position shown in FIG. When the supply of the electric current to the electromagnetic coil 38 is stopped, the valve member 20 causes the return coil spring 3 to return.
The valve member 20 moves in the direction away from the stator 37 by the urging force of the valve member 9 and the contact portion 23 of the valve member 20 contacts the valve seat 16, so that the valve member 20 occupies the closed position shown in FIG.
The electromagnetic coil 38 is connected via a terminal 41 to an electronic control circuit 42 including a microcomputer, and the electronic control circuit 42 controls supply and stop of supply of current to the electromagnetic coil 38.

A flange 43 is integrally provided on the stator 37, and the flange 43 is fixedly attached to the rear end of the valve case 12. A joint portion 44 connected to the branch pipe 8 integrally extends from the end surface of the flange 43 on the side opposite to the stator 37.
A filter 46 is provided inside, and an adjusting pipe 47 for adjusting the urging force of the return coil spring 39 is provided therein. The upstream end of the internal passage 48 of the adjusting pipe 47 communicates with the branch pipe 8 via the joint portion 44, and the downstream end thereof has a central hole 49 formed in the armature 36 and the armature 36. Outer peripheral portion of the flat member 5 of the valve member 20
1, the central hole 52 of the stopper 31, and the valve member 20 and the wall surface of the guide hole 17 are communicated with the above-described fuel metering gap 24 via the fuel passage 53. Thus valve member 2
When 0 occupies the open position shown in FIG. 5, the pressurized fuel from the branch pipe 8 is injected through the gap 24 from the injection hole 14 into the cylinder or into the intake pipe.

The adjusting pipe 4 located upstream of the fuel metering gap 24 in the above-described fuel flow direction.
7 is provided with a metering member 50 having an orifice 50a. Orifice 50a of this metering member 50
Is a fuel metering means for metering the fuel sent to the fuel metering gap 24, and in the case of the illustrated embodiment,
20% to 50% of the predetermined pressure loss is measured by the metering member 5.
0 is responsible for the remaining pressure loss and the fuel metering gap 24
Is set up to handle.

Next, the operation of the electromagnetic fuel injection valve 1 for an internal combustion engine will be described. When no current is supplied from the electronic control circuit 42 to the electromagnetic coil 38 of the electromagnetic actuator 35, the valve member 20 occupies the closed position shown in FIG. 4 by the urging force of the return coil spring 39, and at the closed position, The abutment portion 23 of the valve member 20 abuts the valve seat 16 of the valve body 11 and presents the supply of fuel to the internal combustion engine. When occupying the closed position shown in FIG. 4, the fuel residue in the cylinder or in the intake pipe or the vaporization residue R in the fuel remains in the valve seat 1
6 adheres and deposits on the portion of the valve member 20 downstream of the contacted portion 61 corresponding to the contact portion 23 and on the surface of the portion of the valve member 20 downstream of the contact portion 23. However, when in the closed position, the valve member 20 and the valve seat 16
Since the contact portions 23 and the portions on the upstream side of the contacted portions 61 are disconnected from the direct communication with the inside of the cylinder or the intake pipe by the contact portions 23, the upstream surface The residue R does not adhere or accumulate on the top.

When a current is supplied from the electronic control circuit 42 to the electromagnetic coil 38, the valve member 20 causes the return coil spring 39 to return.
Is attracted to the stator 37 against the urging force of
The valve member 20 occupies the open position shown in FIG. 5 by moving the lift amount H to a position where the valve member 2 contacts the stopper 31. The pressurized fuel from the branch pipe 8 is filtered 46, the orifice 50a of the metering member 50, the internal passage 48 of the adjusting pipe 47, the central hole 49 of the armature 36, and the valve member 20.
Flat portion 51, the central hole 52 of the stopper 31, the fuel passage 5
3, through the fuel metering gap 24, and the injection hole 14, the fuel is injected into the cylinder or the intake pipe. As is apparent from FIG. 5, when the valve member 20 occupies the open position, the fuel flows through the orifice 50a of the metering member 50 and the metering gap 24.
Metering portion defining portion 2 of valve member 20
6, a valve seat 26 on and in cooperation with which defines a gap 24
Since no residue is attached and deposited on the part of
The metering area S1 of is not affected by the residue and can always perform a constant metering action.

Then, as shown in FIG. 1, a step 71 as a diaphragm is formed on a part of the outer peripheral portion of the adjusting pipe 47.
To provide. The step 71 is formed on a part of the outer peripheral wall of the adjusting pipe 47 as an uneven step 73. Outer diameter d ₁ of adjusting pipe 47, outer diameter d of step 71
₂ , the gap δ2 between the inner diameter d _C of the small diameter portion of the joint portion 44 and the step 71 is set smaller than the gap δ1 between the inner diameter d _C of the small diameter portion of the joint portion 44 and the outer diameter d ₁ of the adjusting pipe 47. . Therefore, the leakage flow rate Q that leaks due to the gap δ2
It is possible to suppress the variation of ₂ and reduce the flow rate Q ₂ . This almost eliminates the need for readjustment.

On the other hand, the gap δ2 is applied only to the length L of the step 71 of the adjusting pipe 47. This length L
Is secured by the clearance δ1 so as not to impair the assembling property of the adjusting pipe 47 to the joint portion 44. Next, experimental data is shown in FIG. The experimental data shown in FIG. 6 shows the relationship between the fuel leakage rate ΔQ and the gap δ1 between the inner diameter d _C of the small diameter portion of the joint and the outer diameter d ₁ of the adjusting pipe. Here, the leakage rate ΔQ is ΔQ = Q ₂
/ Represented by Q (Q: injection amount as a target, Q _2: Leakage flow from the gap .delta.1).

According to this experiment, the size of the gap between the inner wall of the hole of the joint portion and the outer wall of the adjusting pipe should be large to some extent in terms of the assemblability. According to the gap δ1 is 0.01
(Mm) ≦ δ1 is required, and the adjustment limit that does not require readjustment is the gap δ1 as shown in FIG.
Is in the range of δ1 ≦ 0.036 (mm). Therefore, the size of the gap δ2 between the inner diameter d _C of the small diameter portion of the joint portion and the step 71 is 0.01 ≦ δ1 ≦ 0.
The range of 036 (mm) resulted in preferable results.

As a result of the experiment, the clearance δ1 is set to 0.01 mm or more for ensuring the assembling property, and 0.0 for adjusting the injection amount.
It is desirable to set it to 36 mm or less. Also, the result of the experiment,
The gap δ2 is preferably 0.02 mm or less in order to suppress variations in the leakage flow rate Q ₂ and reduce the leakage flow rate Q ₂ .
The step length L is about ⅕ or less of the total length of the adjusting pipe, and the distance L1 from the position where the step L is formed to the rear end of the adjusting pipe is in the range of 1 to 5 mm, which hinders the assembling property. I knew it wasn't something.

Next, a method of adjusting the fuel injection valve 1 of this embodiment will be described. The metering of the internal metering type fuel injection valve is performed at two locations, that is, the gap 24 of the valve member 20 and the orifice 50a of the metering member 50 that is press-fitted into the adjusting pipe 47. First seat diameter d _S to form a gap 24 of the valve member 20 in FIG. 3, after setting within a certain range lift H, an injection diameter d _e, attached to the valve body 11 in the valve case 12 together with the stopper 31, the end portion It is fixed by bending 60.

Next, the adjusting pipe 4 having the orifice 50a matching the target injection amount adjustment value
7 is inserted into the fuel injection valve 1. When the injection amount of the fuel injection valve 1 does not reach the target value, the target injection amount Q
50a with different hole diameters until reaching
The adjustment pipe 47 having the above is replaced and fine adjustment is performed.

When this embodiment is compared with the prior art, in the prior art, the adjusting pipe 4 is used because of the processing accuracy of parts.
There was a large variation in the size of the gap δ1 between 7 and the joint portion 44. Therefore, when adjusting the injection amount, even if the adjusting pipe 47 having the orifice 50a matching the target injection amount adjusting value is assembled after setting the gap 24 within a certain range, the adjusting pipe 47 and the joint portion 44 are variation of the gap .delta.1 is, since also varies leak rate Q ₂ from the gap .delta.1, not easily reach the injection quantity Q as a target, also replaced with the adjusting pipe 47 having an orifice 50a having different hole diameters over again, re It had to be adjusted, and the workability of assembly was extremely poor.

On the other hand, in this embodiment, since the step 71 is provided between the adjusting pipe 47 and the joint portion 44, the adjusting pipe 47 and the joint portion 44 are provided.
Since the flow rate leakage from the gap can be regulated, fine adjustment of the injection amount can be easily performed without replacing the adjusting pipe 47 having the orifices 50a with different hole diameters many times.

Further, in this embodiment, since the sealing member such as the O-ring 70 for eliminating the leakage flow rate Q ₂ from the gap δ1 is eliminated, there is an effect that the cost can be reduced. Next, a second embodiment of the present invention is shown in FIG. In the second embodiment shown in FIG. 7, the uneven wall 73 of the joint portion 44 is provided with an uneven step 73 as a throttle for narrowing the passage of the gap formed between the inner wall surface of the hole of the joint portion 44 and the outer wall surface of the adjusting pipe 47. To form. The step 73 as a diaphragm is formed in a predetermined length in the axial direction of the adjusting pipe 47. The step 73 is formed in an uneven shape.

In the second embodiment, the gap δ2 formed by the step 73 formed on the inner wall of the hole of the joint portion 44 and the outer wall surface of the adjusting pipe 47 serves as a throttle for the fuel to suppress the fuel leakage flow rate. There is an effect of doing. In the first embodiment and the second embodiment, the step difference as the diaphragm formed between the inner wall of the hole of the joint portion 44 and the outer wall of the adjusting pipe 47 is formed in an uneven shape. The leak passage in the gap between the adjusting pipe and the joint portion can be narrowed by forming a step with a throttle means such as an annular ring member.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a first embodiment of an electromagnetic fuel injection valve for an internal combustion engine of the present invention.

FIG. 2 is a longitudinal sectional view showing the overall configuration of the first embodiment of the present invention.

FIG. 3 is an enlarged sectional view of a portion surrounded by III in FIG.

FIG. 4 is a view showing a state in which a valve member occupies a closed position in a portion surrounded by IV shown in FIG.

5 is a diagram showing a state in which a valve member occupies an open position in a portion surrounded by IV shown in FIG. 3. FIG.

FIG. 6 is an experimental data diagram showing the relationship between the clearance between the inner wall of the joint hole and the outer wall of the adjusting pipe and the fuel leakage rate according to the embodiment of the present invention.

FIG. 7 is a sectional view showing a main part according to a second embodiment of the present invention.

FIG. 8 is a sectional view showing a main part of a conventional electromagnetic fuel injection valve.

FIG. 9 is a longitudinal sectional view showing the overall configuration of a conventional electromagnetic fuel injection valve.

FIG. 10 is a sectional view showing a main part of a conventional electromagnetic fuel injection valve.

11 is an enlarged cross-sectional view of a portion surrounded by XI in FIG.

12 is an enlarged cross-sectional view showing a modified example of a portion surrounded by XI in FIG.

[Explanation of symbols]

 1 Fuel Injection Valve 11 Valve Main Body 12 Valve Case 14 Injection Hole 16 Valve Seat 17 Guide Hole 20 Valve Member 31 Stopper 35 Electromagnetic Actuator 39 Return Coil Spring (Elastic Member) 44 Joint Part 46 Filter 47 Adjusting Pipe 48 Internal Passage 50 Adjustment Quantity member 50a Orifice 71 Step (throttle) 73 Step (throttle)

Claims (4)

[Claims] 1. A valve main body having an injection hole and a valve seat connected to the injection hole, and an abutting portion, the abutting portion abutting the valve seat to supply fuel to an internal combustion engine. A valve member movably provided between a closed position where the valve is stopped and an open position where the contact portion is separated from the valve seat to allow supply of fuel to an internal combustion engine; An elastic member that urges the valve member to the side, an electromagnetic actuator that moves the valve member to the open position against the urging force of the elastic member, and adjusts the urging force of the elastic member and is formed inside An adjusting pipe for introducing fuel into the valve body through an internal passage, a joint part having a position relative to the valve body and having a hole for accommodating the adjusting pipe, and an outer wall of the adjusting pipe And the inner wall of the hole An electromagnetic fuel injection valve for an internal combustion engine, characterized in that a throttle for narrowing the amount of fuel leakage is provided between the two. 2. The electromagnetic fuel injection valve for an internal combustion engine according to claim 1, wherein the throttle is an uneven step formed on the outer wall of the adjusting pipe. 3. The electromagnetic type for an internal combustion engine according to claim 1, wherein the throttle is formed to have an axial length that does not hinder the assembling property of the adjusting pipe in the axial direction. Fuel injection valve. 4. The internal combustion engine for an internal combustion engine according to claim 1, wherein the throttle is formed to have an axial length that suppresses a fuel leak amount to an extent that a fuel readjustment amount is unnecessary. Electromagnetic fuel injection valve.