JP2002070686A - Fuel injection valve for internal combustion engine and disassembling tool therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the cooling structure of an injection valve tip in a fuel injection valve for internal combustion engine and to facilitate the disassembling and assembling of the fuel injection valve. SOLUTION: The fuel injection valve tip 15 having a nozzle hole 25 and a fuel passage 26 is fitted to and supported by the valve mounting hole 3 of a cylinder head 1 through a nozzle sleeve 7. A water dress part 31 indirectly surrounding the injection valve chip 15 is formed within the nozzle sleeve 7. The water dress part 31 is allowed to communicate with a cooling water jacket 5 within the cylinder head 1 to cool the injection valve tip 15 by use of engine cooling water. A spacer 35 with excellent heat conductivity and good adhesion of copper or the like is interposed between the inside surface of the nozzle sleeve 7 and the outside surface of the injection valve tip 15, whereby the heat conducting efficiency is improved in spite of an indirect cooling system as described above.

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 for an internal combustion engine in which an injection valve tip having an injection port and a fuel passage is fitted and supported in a valve mounting hole of a cylinder head via a nozzle sleeve, and a disassembly tool therefor. About.

[0002]

2. Description of the Related Art FIG. 12 shows a conventional fuel injection valve 99. An injection valve chip 100 constituting the tip of the fuel injection valve 99 is inserted into a valve mounting hole 103 of a cylinder head 102 via a nozzle sleeve 101. The nozzle sleeve 101 is inserted and screwed into the female thread portion 103a of the valve mounting hole 103. A combustion chamber 105 is provided at the tip of the injection valve tip 100.
An injection port 106 is formed which opens into the injection valve chip 100.
Inside, an annular fuel passage 110 communicating with the injection port 106 is provided.
A vertical fuel supply passage 111 and the like are formed, and an annular cooling water chamber 112 and a cooling water supply passage 114 and a return passage 115 communicating with the annular cooling water chamber 112 are formed.

FIG. 11 is a piping diagram showing a cooling water circulation path of the fuel injection valve 99. The fuel injection valve 99 has a cooling water inlet 120 and a cooling water outlet 121, and the cooling water inlet 12
0 is a cooler 125 through an external cooling water supply pipe 124.
And the fresh water pump 126, and the cooling water outlet 121 is
It is connected to a water tank 128 and a fresh water pump 126 via an external cooling water return pipe 127.

[0004]

In the fuel injection valve cooling structure as shown in FIG. 12, the fuel injection valve cooling structure shown in FIG.
As shown in FIG. 1, a cooler 125 dedicated to cooling the injection valve, a fresh water pump 126, a water tank 128 and the like are required, and external piping such as a cooling water supply pipe 124 and a cooling water return pipe 127 is required, so that the number of parts is increased. At the same time, the engine piping structure becomes complicated.

[0005] Further, as shown in FIG.
0, the annular cooling water chamber 112 and the cooling water passage 114,
In the case of forming the nozzle 115, it is necessary to form the injection valve chip 100 in a space-restricted manner together with the fuel passage 110 and the like, so that the structure inside the injection valve chip 100 becomes complicated, and the molding process takes time. At the same time, it is also difficult to secure a sufficient volume of the cooling water chamber 112.

There is a case where fuel oil is supplied to the annular cooling water chamber 112 and the cooling water passages 114 and 115 in FIG. 12 and used for cooling. Pumps and coolers are required, and seals such as pipes and joints have to be strict in order to prevent leakage of fuel oil, which increases piping costs and requires labor for maintenance.

[0007]

According to a first aspect of the present invention, there is provided an injection valve tip having a nozzle and a fuel passage, which is fitted into a valve mounting hole of a cylinder head via a nozzle sleeve. In the fuel injection valve of the internal combustion engine to be supported, a water jacket portion is formed in the nozzle sleeve indirectly surrounding the injection valve chip, and the water jacket portion is communicated with a cooling water jacket in a cylinder head, and is injected by engine cooling water. It is characterized in that the valve chip is cooled.

According to a second aspect of the present invention, in the fuel injection valve for an internal combustion engine according to the first aspect, a spacer having excellent thermal conductivity is closely attached between an inner peripheral surface of the nozzle sleeve and an outer peripheral surface of the injection valve tip. It is characterized by being interposed in.

According to a third aspect of the present invention, in the fuel injection valve for an internal combustion engine according to the second aspect, the spacer has a vertically split slit, and the outer peripheral surface has a small diameter at the injection port side in the valve axis direction. It is characterized in that it is formed in a tapered shape, is tapered into the inner peripheral tapered surface of the nozzle sleeve, and is pressed toward the injection port side in the valve axis direction.

According to a fourth aspect of the present invention, in the fuel injection valve of the internal combustion engine according to the first to third aspects, a fin or a groove is formed in the water robe.

According to a fifth aspect of the present invention, in the fuel injection valve for an internal combustion engine according to the second to fourth aspects, an end of the spacer on the side of the injection port in the direction of the valve axis extends to substantially the ceiling surface of the combustion chamber. It is characterized by having.

According to a sixth aspect of the present invention, there is provided a disassembly tool for extracting the spacer according to any one of the second to fifth aspects, wherein the extraction cylinder includes an expandable engaging claw at a distal end portion thereof, and is provided in the extraction cylinder. An operating rod inserted movably in the cylinder core direction and interlocked and connected to the engaging claw, and the engaging claw is expanded by operating the operating rod to extend the edge of the spacer according to claim 2. It is characterized by engaging.

[0013]

FIG. 1 is a longitudinal sectional view of a cylinder head provided with a fuel injection valve to which the present invention is applied. The cylinder head 1 has a valve mounting from an upper end surface of a cylinder head to a combustion chamber 2 at a lower end. A hole 3 is formed, and a cooling water jacket 5 is formed in various places. A fuel injection valve 4 is mounted on the valve mounting hole 3 via a nozzle sleeve 7. The valve mounting hole 3 is vertically divided by a cooling water jacket 5, and a lower portion of the valve mounting hole 3 is formed in a stepped shape and a female screw 3a is formed. The lower end is screwed.

The nozzle sleeve 7 extends from the lower end facing the combustion chamber 2 to the upper part of the valve mounting hole 3 through the lower part of the valve mounting hole 3 and the cooling water jacket 5, and has an annular inner peripheral surface at the lower end part. The water coat portion forming portion 7a is integrally fixed by welding. The upper end of the nozzle sleeve 7 is an O-ring 10
Is fitted to the inner peripheral surface of the upper part of the valve mounting hole 3 via the hole.

The fuel injection valve 4 comprises a valve body 12 and an injection valve tip 15 joined to a lower end surface of the valve body 12 by a cap nut 14.
6 is pressed down. The presser fitting 16 is inserted through a stud 18 screwed to the cylinder head 1,
It is locked by a nut 19 screwed into the bolt 18.

The lower part of the valve mounting hole 3 and the nozzle sleeve 7
Between them, an annular space 21 is secured, and the annular space 21 opens into the upper cooling water jacket 5 and
The plurality of cooling water passages 22 also communicate with other cooling water jackets 5.

FIG. 2 is an enlarged view of the injector tip 15.
At the lower end of the injection valve tip 15, a plurality of injection ports 25 opening to the combustion chamber 2 are formed, and within the injection valve chip 15, an annular fuel passage 26 communicating with the injection port 25 is formed. It communicates with a fuel passage 28 of the valve body 12 via a vertically extending fuel passage 27 extending upward.

An annular step surface 7b is formed on the outer peripheral surface of the nozzle sleeve 7, and an annular step surface 3b formed in the valve mounting hole 3.
Is press-contacted through an annular packing 30. As described above, the water-coating portion forming portion 7a is integrally welded to the inner peripheral surface of the lower end portion of the nozzle sleeve 7, thereby forming an annular water-coating portion indirectly surrounding the lower half portion of the injection valve chip 15. 31 are formed.

The vertical cross section (cross section including the valve shaft core O1) of the water robe portion 31 is vertically elongated as shown in FIG. 2, and the upper end is formed with a plurality of radially arranged communication holes 33. It communicates with the annular space 21 through the above. The communication hole 33 is formed obliquely upward from the water jacket portion 31. The inner peripheral surface of the water robe portion forming portion 7a is formed in a tapered shape having a small diameter on the lower side (the nozzle side), and a cylindrical shape is provided between the tapered inner peripheral surface and the outer peripheral surface of the injection valve chip 15. The spacer 35 is press-fitted.

The spacer 35 is made of a metal having excellent thermal conductivity, low hardness and conformability, for example, copper, and its outer peripheral surface is formed on the tapered inner peripheral surface of the water robe forming portion 7a. It has a corresponding tapered surface. An annular spacer press 37 made of Teflon (registered trademark) having elasticity is sandwiched between an upper end surface of the spacer 35 and a press step surface 15a formed on the injection valve chip 15. ,
The spacer 35 is pressed downward through the spacer retainer 37, and the inner and outer surfaces of the spacer 35 are inserted into the injection valve chip 1 by wedge action.
5 and the tapered inner peripheral surface of the water robe forming portion 7a. The upper end position of the spacer 35 substantially corresponds to the upper end position of the water coat portion 31, and the lower end 35b of the spacer 35 reaches the lower end position of the water coat portion forming portion 7a, that is, the ceiling surface of the combustion chamber.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2. In order to secure a sufficient flow sectional area, eight communication holes 33 are formed at equal intervals in the circumferential direction, for example. The four cooling water passages 22 of the cylinder head 1 are formed, for example, at equal intervals in the circumferential direction. The spacer 35 has a slit (split) 3 extending over the entire length in the vertical direction.
5a is formed, and the inner diameter in the free state is formed slightly smaller than the outer diameter of the injection valve tip 15.

As for the flow cross-sectional area of the communication hole 33, for example, the sum of the flow cross-sectional areas of the four communication holes 33 is at least equal to or larger than the flow cross-sectional area of the water robe section 31 (cross section cut through the valve shaft O1). It is set as follows.

FIGS. 4 to 6 show a disassembling tool used to pull out the spacer 35 when disassembling the fuel injection valve. In FIG. 4, a disassembly tool for drawing includes an elongated drawing tube 41,
A centering member 42 fixed to the lower end of the drawing tube 41; and an engaging claw 44 fixed to the lower end of the centering member 42 so as to be expandable.
The operation rod 45 inserted into the extraction tube 41 and the extraction tube 4
1, a jack nut 47 screwed to the upper outer peripheral surface, an opening / closing operation bolt 48 screwed to the inner peripheral surface of the upper end portion of the extraction tube 41, and abutting against the upper end of the operation rod 45, and the like. Fixed base 50 fixed to 1
Is vertically movably inserted into the guide hole 51, and the pull-out tube 41 is gradually pulled up by rotating the jack nut 47.

FIG. 5 is an enlarged view of the lower end portion of the disassembly tool. The centering member 42 performs the centering action by being fitted to the inner peripheral surface of the nozzle sleeve 7.
Is formed in a cylindrical shape, and can be expanded radially outward by being divided into a plurality of parts. The outer periphery of the engaging claw 4 is engaged with the lower end edge of the spacer 35 at the time of expansion. Step surface 4
4a are formed.

A conical portion 45a formed at the lower end of the operating rod 45 is inserted into the inner periphery of the engaging claw 44, and a tapered receiving portion 44b abutting on the conical portion 45a is formed. By pressing down the rod 45, each engagement claw 44 is configured to expand radially outward through the tapered receiving portion 44b.

FIG. 6 is a sectional view taken along the line VI-VI of FIG. 5, and the engaging claw 44 is divided into, for example, four.

[0027]

The engine cooling water discharged from a water pump (not shown) mounted on the engine is supplied to a cooling water jacket in the cylinder to cool the cylinder and then cool the cylinder head 1 shown in FIG. The water is supplied to the water jacket 5 to cool the suction / exhaust passage and the suction / exhaust valves, etc., and is supplied to the annular space 21 through the cooling water passage 22.
Is supplied to the water coating section 31 through some of the communication holes 33 to indirectly cool the lower half portion of the injection valve chip 15.

In FIG. 2, between the inner peripheral surface of the water-coating portion forming portion 7a of the nozzle sleeve 7 and the outer peripheral surface of the injection valve chip 15, a spacer 35 having good heat conductivity, which is in close contact with both surfaces, is arranged. Therefore, the injection valve chip 1
5 can be efficiently cooled.

As shown in FIG. 3, eight communication holes 33 are formed, and a half (four) of the communication holes 33 has a total flow cross-sectional area that is equal to or larger than the flow cross-sectional area of the water robe section 31. It is possible to sufficiently secure the inflow amount and the outflow amount from the water robe portion 31, whereby the cooling water in the water robe portion 31 is promptly replaced, and the injection valve chip 15 is efficiently cooled.

[0030]

[Removal method] In FIG. 1, when removing the fuel injection valve 4, the fuel high pressure pipe 55 is removed from the fuel injection valve 4, the nut 19 of the presser fitting 16 is removed, and the fuel injection valve 4 is connected to the valve mounting hole 3. Pull upward from At this time, even if the cooling water remains in the water robe portion 31 of the nozzle sleeve 7, it does not leak into the combustion chamber 2.

Even when the fuel injection valve 4 is pulled out, the spacer 35 is left in the nozzle sleeve 7, so that the spacer 35 is pulled upward by using a disassembly tool for pulling out shown in FIG. That is, the extraction tube 41 is inserted into the guide hole 51 of the fixed base 50 fixed to the cylinder head 1, and
Then, the aligning member 42 is inserted into the nozzle sleeve 7, and the engaging claw 44 is inserted into the spacer 35 while centering is performed by the aligning member 42.
From the bottom.

Next, by turning the operating bolt 48 at the upper end to push down the operating rod 45, the lower end conical portion 45 in FIG.
The engagement claw 44 is expanded by the wedge action of the a.
The step surface 44a is engaged with the lower end of the step.

Then, by rotating the jack nut 47 shown in FIG. 4 in a state where the jack nut 47 is in contact with the fixed base 50, the drawing tube 41 is gradually pulled up, and the spacer 35 is pulled out from the nozzle sleeve 7. Therefore, the spacer 35 can be pulled out without disassembling the cylinder head 1.

[0034]

[Mounting method] In FIG. 2, when mounting the fuel injection valve 4, a new spacer presser 37 is provided around the outer periphery of the injection valve chip 15.
The new spacer 35 is successively fitted, and the spacer 35 and the spacer presser 37 are held undetachably by the interference fitting action of the spacer 35.

In FIG. 1, the spacer presser 37 as described above is used.
Then, the fuel injection valve 4 equipped with the spacer 35 is inserted into the valve mounting hole 3, and is pressed from above by the holding metal 16. At this time, the spacer presser 37 is compressed in the vertical direction by its elastic force, and at the same time, presses down the spacer 35 so that the inner and outer surfaces of the spacer 35 are in contact with the outer peripheral surface of the injection valve chip 15 and the nozzle sleeve 7.
Is adhered to the inner peripheral surface of the water robe forming section 7a.

[0036]

[Other Embodiments of the Invention] (1) FIG.
In order to extend the heat transfer area of the
FIG. 8 shows an example in which a groove 61 is formed in the water coat portion 31. When the fins 60 or the grooves 61 are formed in a spiral shape, the flow of the cooling water can be spirally rectified, the flow velocity can be increased, and the heat exchange rate can be improved.

(2) FIG. 9 shows that every other communication hole 33 is
The structure is such that it is inclined so as to face the tangential direction of the clothes section 31, thereby generating a swirling flow in the clothes section 31 and improving the cooling efficiency.

(3) FIG. 10 shows a modified example of the spacers, and a pair of inner and outer spacers 65 and 6 arranged upside down.
6 is an example in which a nozzle sleeve 7 is interposed between a water robe forming section 7a and an injection valve tip 15. Inner spacer 65
The outer spacer 66 is formed in a taper having a smaller diameter as the inner peripheral surface goes down, and the outer spacer 66 is formed in a taper having a smaller diameter as the outer peripheral surface goes downward.
5, 66 tapered surfaces are in contact with each other. By using the pair of spacers 65 and 66 that are taperedly fitted to each other, the outer peripheral surface of the injection valve tip 15 and the inner peripheral surface of the nozzle sleeve 7 can be straightened.

(4) Although copper is used as the spacer 35 in the above embodiment, other metals or resins having good thermal conductivity and good conformability (adhesion) can also be used. It is.

(5) In FIG. 2, although the outer peripheral surface of the spacer 35 and the inner peripheral surface of the water robe forming portion 7a of the nozzle sleeve 7 are taperedly fitted, the inner peripheral surface of the spacer 35 is additionally provided. And the outer peripheral surface of the injection valve tip 15 may be tapered into a smaller diameter as it goes downward.

(6) A tool engagement hole is formed in the spacer 35,
The claw of the disassembly tool may be engaged with the engagement hole and pulled out.

[0042]

As described above, according to the present invention, (1) the injection valve chip 15 having the injection port 25 and the fuel passage 26 is fitted and supported in the mounting hole 3 of the cylinder head 1 via the nozzle sleeve 7. In the fuel injection valve of the internal combustion engine, a water coating portion 31 for indirectly cooling the injection valve chip 15 is formed in the nozzle sleeve 7, and the water coating portion 31 communicates with the cooling water jacket 5 in the cylinder head 1. In addition, since the injection valve chip 15 is cooled using the engine cooling water, a cooling pipe, a cooler and a cooling pipe dedicated to the injection valve chip are provided separately from the circulation path of the engine cooling water as in the conventional example of FIG. It is not necessary to provide a device such as a pump, so that the number of parts of the engine can be reduced and the cost of parts can be reduced.

(2) Since a pipe and a joint dedicated to cooling the injection valve chip are not required, the structure around the injection valve is simplified, and the fuel injection valve can be easily disassembled and assembled.

(3) Since it is not necessary to form a cooling water chamber and a cooling water passage in the injection valve chip as shown in FIG.
The structure of the injection valve tip itself can be simplified.

(4) If the spacer 35 having excellent thermal conductivity and good adhesion is interposed between the inner peripheral surface of the nozzle sleeve 7 and the outer peripheral surface of the injection valve chip 15, an indirect cooling structure is obtained. However, the heat transfer efficiency between the water coat portion 31 and the injection valve chip 15 can be improved, and the cooling performance can be improved.

(5) The slit 35 having a vertically split shape is formed in the spacer 35.
is formed, and the spacer 35 and the inner peripheral surface of the nozzle sleeve 7 are tapered into a small diameter at the injection port side in the valve axis direction, and are pressed toward the injection port side in the valve axis O1 direction by the spacer presser 37. In this case, the adhesion between the nozzle sleeve 7 and the injection valve chip 15 can be easily increased by the wedge action of the spacer 35 at the time of assembly, and the heat transfer efficiency can be increased.

(6) The fins 60 or the grooves 61
Is formed, the heat transfer efficiency can be further improved.

(7) By extending the tip of the spacer 35 on the injection port side in the valve axis direction to the substantially ceiling surface of the combustion chamber 2, it is possible to sufficiently cool the vicinity of the injection port where the temperature rise is large.

(8) According to the disassembly tool described in claim 6, the operation of the operating rod 45 opens the engaging claw 44 at the lower end and engages with the lower end of the spacer 35.
When disassembling the fuel injection valve, the spacer 35 can be pulled upward without disassembling the cylinder head 1, thereby improving the efficiency of the disassembling operation.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a fuel injection valve of an internal combustion engine to which the present invention is applied.

FIG. 2 is an enlarged view of a lower end portion of FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a longitudinal sectional view of a disassembly tool for drawing showing a spacer drawing operation.

FIG. 5 is an enlarged view of a lower end portion of FIG.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is an enlarged longitudinal sectional view showing a modification of the water robe section.

FIG. 8 is an enlarged longitudinal sectional view showing a modified example of the water robe section.

FIG. 9 is a horizontal sectional view similar to FIG. 3, showing a modification of the communication hole of the water robe.

FIG. 10 is an enlarged longitudinal sectional view showing a modification of the spacer.

FIG. 11 is a schematic diagram of a conventional pipe.

FIG. 12 is a longitudinal sectional view of a conventional fuel injection valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Combustion chamber 3 Valve mounting hole 4 Fuel injection valve 5 Cooling water jacket 7 Nozzle sleeve 7a Water robe forming part 15 Injection valve chip 21 Annular space 22 Cooling water passage 25 Injection port 26 Annular fuel passage 31 Water robe 33 Communication Hole 35 Spacer 35a Slit 37 Spacer retainer 41 Pull-out tube 42 Alignment member 44 Engagement claw 45 Operation rod 47 Jack nut 48 Operation bolt

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F02M 61/16 F02M 61/16 V (72) Inventor Shunji Hamaoka 1-32 Chayacho, Kita-ku, Osaka-shi, Osaka No. Within Yanmar Diesel Co., Ltd. (72) Shusuke Okada, Inventor 1-32 Chaya-cho, Kita-ku, Osaka, Osaka Prefecture Within Yanmar Diesel Co., Ltd. No. Within Yanmar Diesel Co., Ltd. (72) Inventor Toshiyuki Chiyo 1-32 Chayamachi, Kita-ku, Osaka, Osaka Prefecture F-term within the Yanmar Diesel Co., Ltd. 3G024 AA04 CA05 CA09 CA27 DA02 3G066 AA07 AB02 AD12 BA53 CC05T CD10 CD15 CD23

Claims (6)

[Claims] 1. A fuel injection valve for an internal combustion engine in which an injection valve chip having an injection port and a fuel passage is fitted and supported in a valve mounting hole of a cylinder head via a nozzle sleeve, wherein the injection valve chip is indirectly mounted in the nozzle sleeve. A fuel injection valve for an internal combustion engine, wherein the water coating portion is communicated with a cooling water jacket in a cylinder head to cool an injection valve chip with engine cooling water. . 2. A fuel for an internal combustion engine according to claim 1, wherein a spacer having excellent thermal conductivity is interposed between the inner peripheral surface of the nozzle sleeve and the outer peripheral surface of the injection valve tip in a close contact state. Injection valve. 3. The spacer has a vertically split slit, and the outer peripheral surface is formed in a tapered shape having a small diameter on the injection port side in the valve axis direction, and is tapered into the inner peripheral tapered surface of the nozzle sleeve. 3. The fuel injection valve for an internal combustion engine according to claim 2, wherein the fuel injection valve is pressed toward an injection port side in a valve axis direction. 4. The fuel injection valve for an internal combustion engine according to claim 1, wherein a fin or a groove is formed in the water robe. 5. The fuel injection valve for an internal combustion engine according to claim 2, wherein a front end of the spacer on the side of the injection port in the valve axis direction extends substantially to a ceiling surface of the combustion chamber. 6. An operation device comprising: a drawing cylinder having an expandable engaging claw at a distal end thereof; and an operation rod inserted into the drawing cylinder so as to be movable in a tube core direction and operatively connected to the engaging claw. The disassembly tool for a fuel injection valve of an internal combustion engine, wherein an engaging claw is extended by operating a rod to engage with an end edge of the spacer.