JP4215380B2 - Fuel injection valve for internal combustion engine and its disassembly tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection valve for an internal combustion engine in which an injection valve chip having a nozzle hole 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 thereof.
[0002]
[Prior art]
FIG. 12 shows a conventional fuel injection valve 99, and 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, and the nozzle sleeve 101 is screwed into the female thread portion 103 a of the valve mounting hole 103. A nozzle hole 106 that opens to the combustion chamber 105 is formed at the tip of the injection valve chip 100, and an annular fuel passage 110 that communicates with the nozzle hole 106, a soot-facing fuel supply passage 111, and the like are formed in the injection valve chip 100. In addition, an annular cooling water chamber 112, a cooling water supply passage 114 and a return passage 115 communicating with the annular cooling water chamber 112 are formed.
[0003]
FIG. 11 is a piping diagram showing a cooling water circulation path of the fuel injection valve 99. The fuel injection valve 99 is formed with a cooling water inlet 120 and a cooling water outlet 121. The cooling water inlet 120 is an external cooling water supply pipe. The cooling water outlet 121 is connected to the water tank 128 and the fresh water pump 126 via the external cooling water return pipe 127 via the cooling water 125 and the fresh water pump 126 via 124.
[0004]
[Problems to be solved by the invention]
In the fuel injection valve cooling structure as shown in FIG. 12, in addition to the circulation path of the engine coolant, a cooler 125, a fresh water pump 126, a water tank 128, etc. dedicated to the injection valve cooling are required as shown in FIG. External piping such as the supply pipe 124 and the cooling water return pipe 127 is required, which increases the number of components and complicates the piping structure of the engine.
[0005]
Further, as shown in FIG. 12, when the annular cooling water chamber 112 and the cooling water passages 114 and 115 are formed directly in the injection valve chip 100, the fuel passage 110 and the like in the injection valve chip 100 limited in space. In addition, the structure inside the injection valve chip 100 becomes complicated, and it takes time and effort to form the cooling water chamber 112, and it is difficult to secure the cooling water chamber 112 having a sufficient volume.
[0006]
In addition, fuel oil may be supplied to the annular cooling water chamber 112 and the cooling water passages 114 and 115 in FIG. 12 to be used for cooling. As in the case of the cooling water, a pump dedicated to cooling the fuel injection valve and A cooler and the like are required, and seals such as pipes and joints must be tightened to prevent fuel oil leakage, resulting in high pipe costs and troublesome maintenance.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, an invention according to claim 1 of the present invention is a fuel injection valve for an internal combustion engine in which an injection valve chip having a nozzle hole and a fuel passage is fitted and supported in a valve mounting hole of a cylinder head via a nozzle sleeve. ,
A water garment part indirectly surrounding the injection valve chip is formed in the nozzle sleeve, the water garment part is communicated with a cooling water jacket in the cylinder head, and the injection valve chip is cooled by engine cooling water. It is characterized by.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, an invention according to claim 1 of the present invention is a fuel injection valve for an internal combustion engine in which an injection valve chip having a nozzle hole and a fuel passage is fitted and supported in a valve mounting hole of a cylinder head via a nozzle sleeve. to form a Mizukoromo part indirectly surrounds the injector tip into the nozzle sleeve, the aqueous radical 145 communicates with a cooling water jacket in the cylinder head, so as to cool the injector tip by the engine cooling water, the A spacer having excellent thermal conductivity is interposed between the inner tapered surface of the nozzle sleeve and the outer peripheral surface of the injection valve chip in a close contact state, and the spacer has a split slit and the outer peripheral surface. Is formed in a tapered shape having a small diameter on the nozzle hole side in the valve axis direction, is taper-fitted to the inner peripheral tapered surface of the nozzle sleeve, and is pressed into the nozzle hole side in the valve axis direction .
[0009]
According to a second aspect of the present invention, in the fuel injection valve for the internal combustion engine according to the first aspect, the tip of the spacer in the direction of the valve axis extends toward the substantially ceiling surface of the combustion chamber.
[0010]
The invention described in claim 3 is a disassembling tool for pulling out the spacer according to claim 1 or 2, wherein the pulling cylinder is provided with an expandable engaging claw at the tip portion, and the cylinder core is provided in the pulling cylinder. An operating rod inserted into the engaging claw and interlockingly connected to the engaging claw, and the engaging claw is expanded by operation of the operating claw, and is engaged with the edge of the spacer according to claim 1 or 2. It is characterized by the fact that they are combined.
[0014]
The nozzle sleeve 7 extends from the lower end facing the combustion chamber 2 to the lower portion of the valve mounting hole 3 and the cooling water jacket 5 to the upper portion of the valve mounting hole 3. The forming portion 7a is integrally fixed by welding. The upper end portion of the nozzle sleeve 7 is fitted to the inner peripheral surface of the upper portion of the valve mounting hole 3 via the O-ring 10.
[0015]
The fuel injection valve 4 includes a valve main body 12 and an injection valve chip 15 coupled to a lower end surface of the valve main body 12 by a cap nut 14 and is pressed by a presser fitting 16 from above. The presser fitting 16 is inserted into a stud bolt 18 screwed into the cylinder head 1 and is locked by a nut 19 screwed into the bolt 18.
[0016]
An annular space 21 is secured between the lower portion of the valve mounting hole 3 and the nozzle sleeve 7, and the annular space 21 opens into the upper cooling water jacket 5 and includes a plurality of cooling water passages 22. The other cooling water jacket 5 is also communicated.
[0017]
FIG. 2 is an enlarged view of the injection valve chip 15. A plurality of injection holes 25 that open to the combustion chamber 2 are formed at the lower end of the injection valve chip 15, and the injection valve chip 15 has an annular shape that communicates with the injection hole 25. A fuel passage 26 is formed, and the annular fuel passage 26 communicates with the fuel passage 28 of the valve body 12 through a saddle-facing fuel passage 27 extending upward.
[0018]
An annular step surface 7 b is formed on the outer peripheral surface of the nozzle sleeve 7 and is in pressure contact with the annular step surface 3 b formed in the valve mounting hole 3 via an annular packing 30. As described above, the water robe forming portion 7a is integrally welded to the inner peripheral surface of the lower end portion of the nozzle sleeve 7 so as to indirectly surround the lower half portion of the injection valve chip 15. 31 is formed.
[0019]
The vertical cross-sectional shape (cross section including the valve shaft core O1) of the swimsuit portion 31 is long in the vertical direction as shown in FIG. 2, and the upper end portion is formed through the plurality of communication holes 33 arranged radially. It communicates with the annular space 21. The communication hole 33 is formed obliquely upward from the swimsuit portion 31. The inner peripheral surface of the swimsuit portion forming portion 7a is formed in a tapered shape whose lower side (the nozzle hole side) has a small diameter, and a tubular shape is formed between the tapered inner peripheral surface and the outer peripheral surface of the injection valve chip 15. A spacer 35 is press-fitted.
[0020]
The spacer 35 is formed of a metal having excellent thermal conductivity, low hardness, and conformability, such as copper, and the outer peripheral surface is a taper corresponding to the tapered inner peripheral surface of the swimsuit portion forming portion 7a. It is a surface. An annular spacer presser 37 made of elastic Teflon or the like is sandwiched between the upper end surface of the spacer 35 and the presser step surface 15a formed on the injection valve chip 15, The spacer 35 is pressed downward via the spacer presser 37, and the wedge inner action causes both the inner and outer surfaces of the spacer 35 to become the outer peripheral surface of the injection valve chip 15 and the tapered inner peripheral surface of the water robe forming portion 7a. It is in close contact. The upper end position of the spacer 35 substantially corresponds to the upper end position of the swimsuit portion 31, and the lower end 35b of the spacer 35 reaches the lower end position of the swimsuit portion forming portion 7a, that is, the combustion chamber ceiling surface.
[0021]
FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 2, and eight communicating holes 33 of the nozzle sleeve 7 are formed, for example, at equal intervals in the circumferential direction in order to ensure a sufficient flow cross-sectional area. For example, four cooling water passages 22 of the cylinder head 1 are formed at equal intervals in the circumferential direction. The spacer 35 is formed with slits (cracks) 35a extending over the entire length in the vertical direction, and the inner diameter in the free state is slightly smaller than the outer diameter of the injection valve chip 15.
[0022]
The flow cross-sectional area of the communication hole 33 is set so that, for example, the sum of the flow cross-sectional areas of the four communication holes 33 is at least equal to or greater than the flow cross-sectional area of the swimsuit portion 31 (cross section cut by the valve shaft core O1). Has been.
[0023]
4 to 6 show a disassembling tool used for pulling out the spacer 35 when disassembling the fuel injection valve. In FIG. 4, the disassembling tool for drawing includes an elongated drawing tube 41, an alignment member 42 fixed to the lower end portion of the extraction tube 41, and an engaging claw fixed to the lower end of the alignment member 42 so as to be expandable. 44, an operating rod 45 inserted into the drawing tube 41, a jack nut 47 screwed into the upper outer peripheral surface of the drawing tube 41, and an upper end of the operating tube 45 while screwing into the inner peripheral surface of the upper end portion of the drawing tube 41 The pull-out tube 41 is inserted into the guide hole 51 of the fixed base 50 fixed to the cylinder head 1 so as to be movable in the vertical direction, and the jack nut 47 is rotated to rotate it. The tube 41 is gradually pulled up.
[0024]
FIG. 5 is an enlarged view of the lower end portion of the disassembling tool. The alignment member 42 is adapted to perform alignment by fitting to the inner peripheral surface of the nozzle sleeve 7, and the engaging claw 44 is cylindrical. It is formed and can be expanded radially outward by being divided into a plurality, and a step surface 44a that engages with the lower edge of the spacer 35 at the time of expansion is provided on the outer periphery of the engaging claw 4. Is formed.
[0025]
A conical portion 45a formed at the lower end portion of the operating rod 45 is inserted on the inner periphery of the engaging claw 44, and a taper receiving portion 44b that contacts the conical portion 45a is formed. By pushing down, each engaging claw 44 is configured to expand radially outward via the taper receiving portion 44b.
[0026]
6 is a cross-sectional view taken along the line VI-VI in FIG. 5, and the engaging claw 44 is divided into, for example, four parts.
[0027]
[Action]
Engine cooling water discharged from a water pump (not shown) installed in the engine is supplied to a cooling water jacket in the cylinder, and after cooling the inside of the cylinder, the cooling water jacket 5 of the cylinder head 1 shown in FIG. And is supplied to the annular space 21 through the cooling water passage 22, and from the annular space 21 through some of the communication holes 33 to the swimsuit portion. 31 and indirectly cools the lower half of the injection valve chip 15.
[0028]
In FIG. 2, between the inner peripheral surface of the swimsuit portion forming portion 7 a of the nozzle sleeve 7 and the outer peripheral surface of the injection valve chip 15, a spacer 35 having good thermal conductivity that is in close contact with both surfaces is disposed. Even with the indirect cooling structure, the injection valve chip 15 can be efficiently cooled.
[0029]
As shown in FIG. 3, eight communication holes 33 are formed, and the total flow cross-sectional area of half (four) of the communication holes 33 is equal to or larger than the flow cross-sectional area of the water robe portion 31. A sufficient amount of outflow from the swimsuit portion 31 can be ensured, whereby the cooling water in the swimsuit portion 31 is quickly 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 pulled upward from the valve mounting hole 3. At this time, even if cooling water remains in the swimsuit portion 31 of the nozzle sleeve 7, it does not leak into the combustion chamber 2.
[0031]
Even when the fuel injection valve 4 is pulled out, the spacer 35 is left behind in the nozzle sleeve 7, so the spacer 35 is pulled upward using the disassembling tool for extraction shown in FIG. 4. That is, the extraction tube 41 is inserted into the guide hole 51 of the fixed base 50 fixed to the cylinder head 1, the engaging claw 44 and the alignment member 42 are inserted into the nozzle sleeve 7, and the alignment member 42 performs centering. Then, the engaging claw 44 is protruded downward from the spacer 35.
[0032]
Next, the operating bolt 48 at the upper end is rotated to push down the operating rod 45, whereby the engaging claw 44 is expanded by the wedge action of the lower end conical portion 45a of FIG. 5, and the step surface 44a is engaged with the lower end of the spacer 35. Combine.
[0033]
Then, by rotating the jack nut 47 in FIG. 4 in contact with the fixed base 50, the pulling 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 the fuel injection valve 4 is attached, a new spacer presser 37 and a new spacer 35 are sequentially fitted on the outer periphery of the injection valve chip 15, and the spacer 35 and the spacer are fitted by an interference fitting action of the spacer 35. The presser foot 37 is held so as not to fall off.
[0035]
In FIG. 1, the fuel injection valve 4 equipped with the spacer presser 37 and the spacer 35 as described above is inserted into the valve mounting hole 3 and pressed from above by the presser fitting 16. At this time, the spacer presser 37 is compressed in the vertical direction by its elastic force, and the spacer 35 is pressed downward, and both the inner and outer surfaces of the spacer 35 are connected to the outer peripheral surface of the injection valve chip 15 and the swimsuit portion of the nozzle sleeve 7. It is made to contact | adhere to the internal peripheral surface of the formation part 7a.
[0036]
[Other Embodiments]
(1) FIG. 7 is an example in which fins 60 are formed in the swimsuit part 31 in order to expand the heat transfer area of the swimsuit part 31, and FIG. 8 is an example in which the groove 61 is formed in the swimsuit part 31. . When the fin 60 or the groove 61 is formed in a spiral shape, the flow of the cooling water can be rectified in a spiral shape, the flow velocity can be increased, and the heat exchange rate can be improved.
[0037]
(2) FIG. 9 shows a structure in which every other communication hole 33 is inclined so as to face the tangential direction of the water robe portion 31, thereby generating a swirl flow in the water robe portion 31 and improving the cooling efficiency. It is.
[0038]
(3) FIG. 10 is a modified example of the spacer, and a pair of inner and outer spacers 65 and 66 arranged in an upside down direction are connected to the water robe forming portion 7 a of the nozzle sleeve 7 and the injection valve chip 15. It is an example intervening in between. The inner spacer 65 is formed in a taper having a smaller diameter as the outer peripheral surface goes downward, and the outer spacer 66 is formed in a taper having a smaller diameter as the inner peripheral surface goes downward. The tapered surfaces of the spacers 65 and 66 are in contact with each other. By using the pair of spacers 65 and 66 that are tapered to each other in this way, both the outer peripheral surface of the injection valve chip 15 and the inner peripheral surface of the nozzle sleeve 7 can be straightened.
[0039]
(4) Although copper is used as the spacer 35 in the above embodiment, other metals or resins having good thermal conductivity and good conformability (adhesiveness) can be used.
[0040]
(5) In FIG. 2, 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 taper-fitted, but in addition to this, the inner peripheral surface of the spacer 35 and the injection valve The outer peripheral surface of the chip 15 may be tapered so that the diameter decreases as it goes downward.
[0041]
(6) A tool engagement hole may be formed in the spacer 35, and a claw of the disassembling tool may be engaged and removed from the engagement hole.
[0042]
【The invention's effect】
As explained above, according to the present invention,
(1) In a fuel injection valve of an internal combustion engine in which an injection valve chip 15 having an injection hole 25 and a fuel passage 26 is fitted and supported in the mounting hole 3 of the cylinder head 1 via the nozzle sleeve 7, A water robe portion 31 for indirectly cooling the injection valve chip 15 is formed, and the water robe portion 31 communicates with the cooling water jacket 5 in the cylinder head 1 to cool the injection valve chip 15 using engine cooling water. Therefore, as in the conventional example of FIG. 11, it is not necessary to provide equipment such as a cooling pipe, a cooler and a pump dedicated to the injection valve chip separately from the circulation path of the engine cooling water. As well as part costs.
[0043]
(2) Since the piping and joints dedicated for cooling the injection valve tip are not required, the structure around the injection valve is simplified, and the fuel injection valve can be easily disassembled and assembled.
[0044]
(3) Since it is not necessary to form the cooling water chamber and the cooling water passage in the injection valve chip as shown in FIG. 12, the structure of the injection valve chip itself can be simplified.
[0045]
(4) When a 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, The heat transfer efficiency between the garment part 31 and the injection valve chip | tip 15 can be improved, and cooling performance can be improved.
[0046]
(5) A slit 35a having a split shape is formed in the spacer 35, and the spacer 35 and the inner peripheral surface of the nozzle sleeve 7 are tapered to have a small diameter on the nozzle hole side in the valve shaft core direction. By pressing the nozzle shaft 7 toward the nozzle hole side in the direction of the valve axis O1, the wedge action of the spacer 35 during assembly can easily increase the adhesion between the nozzle sleeve 7 and the injection valve chip 15 and transfer heat. Efficiency can be increased.
[0047]
(6) The heat transfer efficiency can be further improved by forming the fin 60 or the groove 61 in the swimsuit portion 31.
[0048]
(7) By extending the tip of the spacer 35 on the nozzle axis 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 nozzle hole where the temperature rise is large.
[0049]
(8) According to the disassembling tool described in claim 3 , the lower end engaging claw 44 is opened and engaged with the lower end of the spacer 35 by the operation of the operating rod 45. At this time, the spacer 35 can be pulled upward without disassembling the cylinder head 1, and the efficiency of the disassembling work is improved.
[Brief description of the drawings]
FIG. 1 is a cross-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.
3 is a cross-sectional view taken along the line III-III in FIG.
FIG. 4 is a cross-sectional view of a pull-out disassembling tool showing a state during spacer pull-out work.
FIG. 5 is an enlarged view of a lower end portion of FIG.
6 is a cross-sectional view taken along the line VI-VI in FIG.
FIG. 7 is an enlarged cross-sectional view of a heel showing a modification of the swimsuit part.
FIG. 8 is an enlarged cross-sectional view of a heel showing a modification of the swimsuit part.
FIG. 9 is a horizontal sectional view similar to FIG. 3, showing a modification of the communication hole of the swimsuit portion.
FIG. 10 is an enlarged cross-sectional view of a saddle showing a modification of the spacer.
FIG. 11 is a schematic piping diagram of a conventional example.
FIG. 12 is a cross-sectional view of a conventional fuel injection valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Combustion chamber 3 Valve attachment hole 4 Fuel injection valve 5 Cooling water jacket 7 Nozzle sleeve 7a Water robe part formation part 15 Injection valve chip 21 Annular space 22 Cooling water passage 25 Injection hole 26 Annular fuel passage 31 Water robe part 33 Communication Hole 35 Spacer 35a Slit 37 Spacer presser 41 Pull-out tube 42 Alignment member 44 Engaging claw 45 Operation rod 47 Jack nut 48 Operation bolt

Claims (3)

In a fuel injection valve of an internal combustion engine in which an injection valve chip having a nozzle hole and a fuel passage is fitted and supported in a valve mounting hole of a cylinder head via a nozzle sleeve
Forming a swimsuit portion indirectly surrounding the injection valve chip in the nozzle sleeve, communicating the swimsuit portion with a cooling water jacket in the cylinder head, and cooling the injection valve chip with engine cooling water;
Between the inner taper surface of the nozzle sleeve and the outer peripheral surface of the injection valve chip, a spacer having excellent thermal conductivity is interposed in a close contact state,
The spacer has a slit in a split shape, and the outer peripheral surface is formed in a taper shape having a small diameter on the nozzle hole side in the valve shaft core direction, and is taper-fitted to the inner peripheral taper surface of the nozzle sleeve. A fuel injection valve for an internal combustion engine, wherein the fuel injection valve is pressed toward the injection port side in the direction . 2. A fuel injection valve for an internal combustion engine according to claim 1, wherein a tip of the spacer in the direction of the valve axis extends toward the substantially ceiling surface of the combustion chamber . A pull-out cylinder having an expandable engaging claw at its tip, and an operating rod that is inserted into the extracting cylinder so as to be movable in the cylinder core direction and interlocked with the engaging claw, and is engaged by operating the operating rod. A disassembling tool for a fuel injection valve of an internal combustion engine, wherein the pawl is expanded and engaged with the edge of the spacer according to claim 1 or 2.

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