JPH0814137A - Fuel injection valve integrated with ignition plug - Google Patents

Abstract

PURPOSE:To provide a reliable fuel injection valve integrated with an ignition plug in which a high voltage passage part and a magnetic passage part are isolated from each other, and fuel injection and ignition spark can be generated without malfunction and independently at optional timings. CONSTITUTION:When injector drive current is impressed on a coil terminal 26, a magnetic flux is generated at optional timing independetly from a timing forming ignition spark in a magnetic circuit (it is constituted of an armature 14, an electromagnetic coil 15, a magnetic connector 16, and a magnetic housing 17) electrically isolated from a high voltage passage by a plurality of insulating bodies 5, 6, 13, 19, a valve body 12 is moved together with the armature 14 in the reverse direction of the fluid flowing direction, and hence fuel can be injected at optional timing from a nozzle 25. Further, noise generated at impressing high voltage hardly reaches the electromagnetic coil 15, and hence unstable combustion is hardly generated in the engine by generation of malfunction of the electromagnetic type fuel injection valve due to noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve integrally formed with an ignition plug, and more particularly to an ignition plug integrated fuel injection valve having improved reliability.

[0002]

2. Description of the Related Art In recent years, in-cylinder direct injection fuel injection valves are required to realize stratified fuels that meet social needs such as low fuel consumption and low emissions. In the Otto cycle engine that requires the above, there is a large limitation in mounting the injection valve. Therefore, a spark plug integrated fuel injection valve as disclosed in JP-A-1-104961 has been proposed. However, since this is an automatic valve similar to the injection nozzle for diesel engines, there were problems with the injection amount accuracy and the injection timing freedom.
No. 4, No. 3, No. 1, No. 2, No. 6, pp. 38-46, No. 4, No. 6, pp. 187-242, has been proposed.

However, since a high-voltage applying passage for generating a spark shares a part with a magnetic passage generated by a coil, these are strongly affected by noises generated when a high voltage is applied. At this time, the electromagnetic fuel injection valve unit is more likely to malfunction. Further, due to the common use of the high voltage and the magnetic passage, the fuel injection timing and the ignition spark generation timing cannot be overlapped, and each timing is limited. Therefore, for example, when performing the spirit injection or the like in which the required fuel is divided into a plurality of times and injected, a great limitation occurs.

Further, the above-mentioned actual exploitation Sho 63-154760.
In the electromagnetic fuel injection valve disclosed in No. 6, since the valve element of the movable part including the armature is used as a part of the high voltage application passage for generating a spark, the error caused by the above noise In addition to the operation, there are the following problems.

That is, due to the electric erosion caused by the application of a high voltage, the distance of the facing gap between the armature and the iron core portion in the magnetic circuit is changed, or the area of the magnetic facing portion is reduced, so that the electromagnetic fuel injection valve There is a great concern that the characteristics of the will deteriorate. On the other hand, as a method of avoiding it, it may be considered to provide a fuel passage in the insulator, but it is difficult to perform precision processing such as fine perforation as a fuel passage in the insulator, and there is a big problem in workability. Furthermore, in the production of a fuel injection valve integrated with a spark plug as described above, providing a screw directly to a ceramic or the like as an insulator has a problem in screw workability and strength. The insulator is directly pressed and fixed using a method such as screw tightening or caulking. However, since a large torsional torque acts on the insulator, a part of the insulator is likely to be damaged, and the debris deteriorates the oil tightness of the valve portion of the fuel injection valve and lowers the withstand voltage against the applied high voltage, and thus the short circuit. May occur.

In view of the above problems, therefore, the present invention isolates the high voltage passage portion from the magnetic passage portion, and can perform fuel injection and ignition spark generation independently at any time without malfunction. An object of the present invention is to provide a highly reliable spark plug integrated fuel injection valve. Another object of the present invention is to provide a highly reliable spark plug integrated fuel injection valve which prevents electrical erosion due to high voltage application without deteriorating production workability.

Another object of the present invention is to provide a highly reliable spark plug integrated fuel injection valve by preventing damage to the insulator during manufacture.

[0008]

The invention according to claim 1 made in order to achieve the above-mentioned object, the needle is housed so as to be able to advance and retreat in the axial direction thereof by the disappearance and generation of electromagnetic force,
The needle closes the injection hole by its forward movement, and opens the injection hole by backward movement to atomize the fuel and eject the fuel into the combustion chamber.The discharge gap of the spark plug electrode is arranged below the nozzle, and a high voltage is applied via the needle. In the fuel injection valve integrated with a spark plug, the armature and the needle are fixed via the first insulator, and the second insulator is interposed in the stator, so that the magnetic force of the electromagnetic solenoid is reduced. A fuel injection valve integrated with a spark plug characterized in that a high voltage path is isolated from a circuit.

According to a second aspect of the present invention, in the fuel injection valve integrated with a spark plug according to the first aspect, the first insulator is formed into a tubular shape, and the needle is inserted therein. So that the fuel flows toward the ejection hole through the flow passage provided inside the needle or between the needle and the first insulator in the first insulator. A fuel injection valve integrated with a spark plug, which is characterized in that:

On the other hand, the invention as set forth in claim 3 is an ignition plug integrated fuel injection valve having an insulator press-fixed by screwing the fixing member, wherein the fixing member and the insulator are provided. A spark plug integrated fuel injection valve having a washer interposed therebetween.

[0011]

According to the fuel injection valve integrated with a spark plug according to claim 1 having the above construction, the needle moves forward and backward in the axial direction due to the disappearance and generation of the electromagnetic force, and the forward movement closes the injection hole and retreats. Opens the injection holes to atomize the fuel and eject it into the combustion chamber. On the other hand, the high voltage introduced through the needle reaches the spark plug electrode, and ignition spark is generated.

Here, the first insulator is interposed between the armature and the needle, and the second insulator is provided inside the stator.
Since the insulator of (1) is interposed, the magnetic circuit of the electromagnetic solenoid and the high voltage path for generating a spark in the spark plug are isolated. In this way, the passage of the high voltage for generating the spark and the passage of the magnetism generated by the coil are isolated, so that the electromagnetic fuel is not affected by the noise generated when the high voltage is applied. The injection valve does not malfunction. Further, since the high voltage and the magnetic passage are isolated, fuel injection and ignition spark generation can be performed independently at any time, and so-called spirit injection can be performed without any problem. Therefore, a highly reliable spark plug integrated fuel injection valve can be obtained.

According to the second aspect of the present invention, the first insulator is formed in a tubular shape, and the needle is inserted into and joined to the first insulator. Within the first insulator, the needle is provided. Since the flow passage is provided inside the nozzle or between the needle and the first insulator, the fuel flows through the flow passage toward the injection hole.

As described above, since it is not necessary to perform fine processing such as fine drilling on the insulator as a fuel flow passage, the insulator is made of ceramic or the like, which has high electric insulation but is generally difficult to machine. It becomes possible to secure the characteristics as a spark plug. Therefore, it is possible to prevent electrical erosion due to high voltage application and maintain high reliability without deteriorating the production processability.

According to the third aspect of the present invention, when the fixing member is provided with an insulator that is pressed and fixed by screwing the fixing member, a washer is interposed between the fixing member and the insulator. Therefore, the effect of the washer prevents or greatly reduces the action of the torsional stress on the insulator due to the screw tightening, and prevents damage due to the assembling of the insulator formed of brittle material such as ceramic. Therefore, problems such as deterioration of oil tightness of the valve part due to biting of insulator fragments and reduction of withstand voltage due to insulator cracking caused by damage to the insulator are eliminated, and a highly reliable spark plug A body-type fuel injection valve can be provided.

[0016]

EXAMPLE An example of the present invention will be described below. FIG.
FIG. 2 is a sectional view of a main body of an electromagnetic fuel injection valve integrated with a spark plug which is an embodiment of the present invention. A fuel inlet 2 is provided on the upper part of the main body 1, and a fuel pump (not shown)
The fuel pressurized in 1 enters from the fuel inlet portion 2 and flows into the housing 3 which is fixed or integrated with the fuel inlet portion 2 by screw engagement.

The first insulator 5 made of ceramic or the like is pressed and fixed via a washer 28 by a holder 27 that is screw-engaged with the housing 3, and the second insulator 6 also made of ceramic or the like is The washer 2 is provided by the holder 4 that is screw-engaged with the magnetic housing 17.
A magnetic connector (stator) 16 fitted in the magnetic housing 17 is pressed and fixed via 9 through. First
The pressing force of each of the insulator 5 and the second insulator is controlled by applying a predetermined tightening torque by screw rotation.

On the other hand, a fuel flow passage 7 is formed in a gap formed by so-called nested engagement between the first insulator 5 and the second insulator 6, and the fuel flowing into this fuel flow passage is the first A guide 10 which flows through the inside of the insulator 5, is arranged concentrically with the first insulator 5 and is integrally formed with the second insulator 6 by brazing, and the jet arranged concentrically with the guide 10. It flows through the inside of the pipe 9 through the filter 8 fitted on the outer surface of the amount adjusting pipe (hereinafter also simply referred to as the pipe) 9. An armature 14 made of a soft magnetic material is concentrically arranged outside the valve body 12 as a needle of the present invention including a part of the fuel flow passage, with a third insulator 13 interposed therebetween. They are joined by a method such as brazing to form an integral structure.

Further, the first insulator 6 and the third insulator 1
3, and a portion of each set of the first insulator 5 and the second insulator 6 that is close to each other has a nested structure in which one end portion covers the end portions of the other insulators that are close to each other. This is for securing a creepage distance for preventing a high-voltage discharge described later inside the main body 1.

The fuel introduced into the pipe 9 is the spring 1
1 Inside, flow passage in valve body 12 (hereinafter referred to as internal flow passage)
It passes through the valve body 30 through the communication hole 12a and the communication hole 12b. The pipe 9 is a guide 10 by means such as caulking.
The valve body 12 is fixed in the fluid flow direction by a spring 11 that is biased by adjusting the pushing amount of the pipe 9, and in the normal state, the valve body 12 is attached to the valve body 12.
Is placed on the sheet to block the fluid flow passage leading to the injection hole 25.

The electromagnetic coil 15 which is electrically connected to the winding terminal 26 is provided on the outer periphery of the second insulator 6 and the third insulator 13 together with the magnetic connector 16 which is a soft magnetic material, the magnetic housing 17, and the armature 14. The magnetic connector 16 and the armature 14 are concentrically arranged to form a movable gap in which the magnetic connector 16 and the armature 14 face each other, thereby forming a magnetic circuit. When a pulsed injector drive current is applied to the winding terminal 26, the electromagnetic coil 15 is excited to generate an electromagnetic force in the magnetic circuit, and the valve body 12 formed integrally with the armature 14 is generated. Is moved in the direction opposite to the fluid flow direction,
The fluid flow passage communicating with the injection hole 25 is opened, and the fuel spray is injected from the injection hole 25.

On the other hand, inside the first insulator 5, the rods 20 are concentrically and integrally connected by, for example, brazing. Then, the high voltage for generating the ignition spark is generated by the ignition coil (not shown) from the first insulator 5
Electrically insulating high-voltage inlet part 1 formed integrally with
8 is passed through the rod 20 continuous with the inner surface of 8 and is installed in the metal pipe 9, the second insulator 6 and the third insulator 13 via the metal spring 21 which is installed in the first insulator 5. The metal-made spring 11, the third insulator 13, and the fourth insulator 19 reach the metal-made valve body 12 and are guided to the valve-body body 30 which is electrically integrated with the center electrode 22. .
In the gap 24 formed between the center electrode 22 and the ground electrode 23, an ignition spark is generated by the discharge.

In the fuel injection valve of this embodiment having the above-mentioned structure, when the injector drive current is applied to the winding terminal 26 as described above, the insulators 5, 6, 13, 19 made up of the above-mentioned plurality of parts are provided. In the magnetic circuit (consisting of the armature 14, the electromagnetic coil 15, the magnetic connector 16 and the magnetic housing 17) electrically isolated from the high voltage path by any arbitrary time independent of the timing of forming an ignition spark. It is possible to generate a magnetic flux at a certain time, move the valve body 12 together with the armature 14 in the direction opposite to the fluid flow direction, and inject fuel from the injection holes 25 at an arbitrary time.

Furthermore, since noise generated when a high voltage is applied does not easily reach the electromagnetic coil 15, it is unlikely that the electromagnetic fuel injector malfunctions due to the noise and combustion in the engine becomes unstable. In the present invention, by providing the valve body 12 with the internal flow passage 12a and the communication hole 12b for fuel flow, it is not necessary to subject the third insulator 13 to precision machining such as fine drilling as a fuel flow passage. Therefore, it becomes possible to use a ceramic or the like, which has a high electric insulation property but is generally difficult to machine, for the third insulator 13, and the characteristics as an ignition plug can be secured. Further, by providing the flow passages inside and outside the metal valve body 12, it is possible to reduce the weight of the movable portion, which helps improve the responsiveness of the fuel injection valve.

Further, the first insulator 5 and the second insulator 6 are
A holder 27 that rotates with screws through washers 28 and 29.
Since it is pressed and fixed by 4, the washers 28, 2
By the effect of 9, the first insulator 5 and the second insulator 6
The action of torsional stress due to screw tightening is prevented or greatly reduced, and damage due to assembly of the insulator formed of brittle material such as ceramic can be prevented. For this reason,
Problems such as deterioration of oil tightness of the valve portion due to biting of the insulator fragments and reduction of withstand voltage due to cracking of the insulator due to the damage of the insulator are eliminated. These washers 28, 29
The shape may have a sufficient circumference to cover the shapes of the insulators 5 and 6 which are the pressed objects to be tightened.

As a specific application of the above-mentioned fuel injection valve integrated with a spark plug, an in-cylinder direct injection gasoline engine, a spark assist alcohol engine, etc. can be considered.
The present invention is not limited to the embodiments described above, and can be implemented in various modes without departing from the scope of the present invention. For example, FIG. 2 is an enlarged view of the fuel flow passage portion of the valve body 12 in the above embodiment, which is provided with an internal flow passage 12a and a communication hole 12b. In this case, the communication hole 12b was provided in the vicinity of the lower end of the third insulator 13, but in addition to the vicinity of the third insulator 13, a second hole communicating with the internal flow passage 12a as shown in FIG. A communication hole 112b may be provided near the tip of the valve body 12 through the internal flow passage 112a.

FIG. 4 shows another embodiment.
FIG. 4B shows an AA end surface in FIG. In the case of this embodiment, the fuel flow passage is not inside the valve body 122,
It is formed in the gap 113 between the valve body 122 and the third insulator 13. More specifically, the diameter of the valve body 122 is basically smaller than the hollow portion of the third insulator 13, and is separated in the longitudinal direction at three locations, and the flange portions 122a, 122b of the substantially triangular shape,
122c is provided. Therefore, this collar 122
Although a part of a, 122b, 122c contacts the third insulator 13 and is positioned, a gap 113 as a fuel flow passage is formed between the valve body 122 and the third insulator 13. The Rukoto.

[0028]

As described above in detail, according to the first aspect of the present invention, the high voltage passage portion and the magnetic passage portion are isolated from each other, so that the high voltage passage portion is not affected by noise generated when a high voltage is applied. It is an advantage that it is possible to provide a highly reliable spark plug-integrated fuel injection valve in which the electromagnetic fuel injection valve unit does not malfunction and can independently perform fuel injection and ignition spark generation at any time. Produce the effect.

According to the second aspect of the present invention, since the insulator does not need to be subjected to precise processing such as fine drilling as a fuel flow passage, it has a high electrical insulation property, but is generally machined. It is possible to provide a highly reliable spark plug integrated fuel injection valve that makes it possible to use a difficult ceramic or the like as an insulator and prevent electrical erosion due to high voltage application without deteriorating production workability.

On the other hand, according to the third aspect of the present invention, the effect of the washer prevents or greatly reduces the action of the torsional stress on the insulator due to the screw tightening, and the insulator formed of a brittle material such as ceramics is used. It is possible to prevent breakage due to assembly and provide a highly reliable spark plug integrated fuel injection valve.

[Brief description of drawings]

FIG. 1 is a sectional view of a main body of an electromagnetic fuel injection valve integrated with a spark plug which is an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a fuel flow passage portion included in the valve body in FIG.

FIG. 3 is a cross-sectional view showing another mode of the communication hole.

FIG. 4A is a cross-sectional view showing another embodiment of the fuel flow passage, and FIG. 4B is an AA end view of FIG. 4A.

[Explanation of symbols]

1 ... Main body 2 ... Fuel inlet 3
... Housing 4 ... Holder 5 ... First Insulator 6
... second insulator 7 ... fuel flow passage 8 ... filter 9
... pipe 10 ... guide 11, 21 ... spring 12, 11
2, 122 ... Valve bodies 12a, 112a ... Internal flow passages 12b, 112
b ... communication hole 13 ... third insulator 14 ... armature 1
5 ... Electromagnetic coil 16 ... Magnetic connector 17 ... Magnetic housing 1
8 ... High voltage inlet 19 ... Fourth insulator 20 ... Rod 2
2 ... Center electrode 23 ... Ground electrode 24 ... Void 2
5 ... Nozzle hole 26 ... Winding terminal 27 ... Holder 28, 2
9 ... Washer 30 ... Valve body

Front page continuation (72) Inventor Hiroyuki Murai 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.

Claims (3)

[Claims] 1. A needle is housed so as to be able to advance and retreat in its axial direction by the disappearance and generation of electromagnetic force, and the needle closes its injection hole by its forward movement and opens the injection hole by its backward movement to atomize fuel and combust the combustion chamber. In a fuel injection valve integrated with a spark plug, in which a discharge gap of a spark plug electrode is arranged below a nozzle ejecting to an armature and a high voltage is introduced through the needle, an armature and the needle are connected via a first insulator. And a high voltage path are isolated from the magnetic circuit of the electromagnetic solenoid by fixing the second insulating member in the stator. 2. The fuel injection valve integrated with a spark plug according to claim 1, wherein the first insulator is formed in a tubular shape, and the needle is inserted into and joined to the first insulator. In the first insulator, the fuel is configured to flow toward the ejection hole through a flow passage provided inside the needle or between the needle and the first insulator. Fuel injection valve with integrated spark plug. 3. A fuel injection valve integrated with a spark plug, comprising an insulator that is fixed by pressing a fixing member with a screw, wherein a washer is interposed between the fixing member and the insulating member. Characteristic spark plug integrated fuel injection valve.