JP2019120246A - Packing and attachment structure - Google Patents

Abstract

To suppress the production of dew condensation water in a fuel injection valve.SOLUTION: There is provided a packing 16 which is adapted to be gripped between a cylinder head 1 of an internal combustion engine and a fuel injection valve 2. The packing has a packing main body 41, a sealed cavity part 42 formed in the packing main body, and a small-capacity heat transfer liquid 43 sealed into the cavity part, and smaller than the cavity part in a capacity. There is also provided an attachment structure having the packing, and air-tightly attaching the fuel injection valve to the cylinder head.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a packing and a mounting structure, and more particularly to a packing and a mounting structure for airtightly mounting a fuel injection valve on a cylinder head of an internal combustion engine.

  Generally, in an internal combustion engine, particularly a direct injection engine, a shaft of a fuel injection valve is inserted into a shaft insertion hole provided in a cylinder head of the internal combustion engine, and a seat formed in the cylinder head around the shaft insertion hole The fuel injection valve is airtightly attached to the cylinder head by pressing the shoulder formed on the periphery of the shaft of the fuel injection valve with the packing interposed therebetween. The shaft insertion hole is in communication with the combustion chamber in the cylinder, and a plurality of injection holes formed at the tip of the shaft are exposed to the combustion chamber. Fuel of relatively high pressure is injected and supplied radially and radially into the combustion chamber from the plurality of injection holes.

Japanese Patent Application Laid-Open No. 2004-301057

  There is a slight radial gap between the shaft of the fuel injection valve and the shaft insertion hole of the cylinder head. The combustion gas and water vapor and fine water droplets contained in the intake air may intrude into the gap as the engine operates. In this case, when the engine is subsequently stopped, the temperature of the shaft portion of the fuel injection valve decreases, condensation may occur on the surface of the shaft portion located in the insertion hole, and condensation water may be generated on the surface. Due to the dew condensation water, damage such as rusting or corrosion of the shaft may occur.

  Therefore, the present disclosure has been made in view of such circumstances, and an object thereof is to provide a packing and an attachment structure capable of suppressing the generation of dew condensation water on the surface of a fuel injection valve.

According to one aspect of the present disclosure,
A packing adapted to be placed between a cylinder head of an internal combustion engine and a fuel injection valve, the packing comprising:
Packing body,
A closed cavity formed inside the packing body;
Heat solvent having a volume smaller than the volume of the cavity enclosed in the cavity;
A packing is provided, characterized in that it comprises:

  Preferably, the packing further includes a reinforcing member provided in the hollow portion and sandwiched between an upper surface and a lower surface of the packing body.

  Preferably, the packing main body is divided into an upper divided piece and a lower divided piece, and the divided pieces are fixed to each other at both end edges.

  Preferably, the divided pieces are fixed by welding or caulking.

  Preferably, the upper divided piece is formed in a cross-sectional lid plate shape, the lower divided piece is formed in a cross-sectional plate shape, the upper divided piece is inlay fitted to the lower divided piece, and the fitting portion is welded Fixed by

  Preferably, the heat transfer fluid is formed of water, alcohol or a mixture thereof.

According to another aspect of the present disclosure,
An attachment structure for airtightly attaching a fuel injection valve to a cylinder head of an internal combustion engine,
A shaft insertion hole provided in the cylinder head;
A seating surface provided on the cylinder head and formed around the shaft insertion hole;
A shaft portion provided in the fuel injection valve and inserted into the shaft insertion hole with a radial gap therebetween;
A shoulder provided on the fuel injection valve and formed around the shaft;
A packing disposed between the seat and the shoulder;
Equipped with
The packing is
Packing body,
A closed cavity formed inside the packing body;
Heat solvent having a volume smaller than the volume of the cavity enclosed in the cavity;
A mounting structure is provided, characterized in that it comprises:

  Preferably, the packing is in contact with the shaft.

  According to the present disclosure, the generation of condensed water on the surface of the fuel injection valve can be suppressed.

It is a longitudinal section showing an attachment structure concerning an embodiment of this indication. FIG. 2 is a detailed view of a portion II of FIG. 1; It is a longitudinal cross-sectional view of packing. It is a longitudinal cross-sectional view which shows packing when a heat carrier fluid evaporates. It is a longitudinal cross-sectional view which shows the modification of packing. It is a longitudinal cross-sectional view which shows other embodiment.

  Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the following embodiments.

  FIG. 1 is a longitudinal sectional view showing a mounting structure according to the present embodiment. Such a mounting structure is for airtightly mounting the fuel injection valve 2 on the cylinder head 1 of the internal combustion engine (engine). Although the engine of this embodiment is a diesel engine for vehicles, there is no limitation in particular in the kind, the use, etc., for example, an engine may be a gasoline engine.

  The upper and lower parts of the figure mean the upper and lower parts in the vertical direction. C is a central axis (referred to as a valve axis) of the fuel injection valve 2, and the valve axis C extends in the vertical direction. The fuel injection valve 2 is attached to the cylinder head 1 in a downward state with its tip directed downward. Below the cylinder head 1, a combustion chamber 3 in a cylinder (not shown) is formed. The fuel injection valve 2 is applied to, for example, a common rail fuel injection system to inject high pressure fuel into the combustion chamber 3.

  Hereinafter, unless otherwise specified, the axial direction, radial direction and circumferential direction based on the valve axis C will be simply referred to as axial direction, radial direction and circumferential direction. In the case of this embodiment, the valve axis C is coaxial with a central axis (referred to as a cylinder axis) of a cylinder not shown.

  The fuel injection valve 2 includes a valve body 4, a fuel injection nozzle 5 disposed adjacent to the lower side (tip end side) of the valve body 4, and a substantially cylindrical shape for closely attaching the fuel injection nozzle 5 to the valve body 4. And a retaining nut 6. The retaining nut 6 extends axially from its lower end surface 7 to its upper end surface 8. The fuel injection nozzle 5 has a stem 9, which extends axially at a position below the retaining nut 6. The shaft 9 is smaller in diameter than the retaining nut 6. A shoulder 10 of the fuel injection valve 2 is formed by the lower end of the retaining nut 6 around the shaft 9, ie, radially outward of the shaft 9.

  The cylinder head 1 is provided with a valve insertion hole 11 into which the fuel injection valve 2 is coaxially inserted from above. The valve insertion hole 11 is coaxial with the cylinder axis. The valve insertion hole 11 has a large diameter body insertion hole 12 into which the valve body 4 and the retaining nut 6 are inserted, and a small diameter shaft insertion hole 13 into which the shaft 9 is inserted. The shaft insertion hole 13 extends continuously downward and axially from the body insertion hole 12 and opens at the lower surface 14 of the cylinder head 1. Thus, the shaft insertion hole 13 is communicated with the combustion chamber 3 and the body insertion hole 12 is communicated with the combustion chamber 3.

  The lower end of the body insertion hole 12 and the upper end of the shaft insertion hole 13 are connected in a step-like manner by the seat surface 15. The seating surface 15 is an upward annular surface provided on the cylinder head 1 and formed around the upper end of the shaft insertion hole 13 and extending around the entire circumference. The seat 15 is formed by a plane that is perpendicular (i.e., horizontal) in the axial direction. The fuel injection valve 2 is airtightly attached to the cylinder head 1 by pressing the shoulder portion 10 from the upper side to the seating surface 15 via the packing 16. The fuel injection valve 2 is axially pressed downward by a fork-like member (not shown) at an upper position outside the figure.

  FIG. 2 shows the details of part II of FIG. The fuel injection nozzle 5 forms a substantial injection portion of fuel, and includes a substantially cylindrical nozzle body 17 and a needle valve 18 (shown by a phantom line) coaxially and movably accommodated in the nozzle body 17. Equipped with

  The nozzle body 17 includes, in order from the top, the first portion 19 having an outer diameter D1, the second portion 20 having an outer diameter D2 (<D1), and the above-described shaft portion 9 having an outer diameter D3 (<D2) It integrally has a tapered portion 21 whose outer diameter is gradually reduced as it goes downward, and a substantially hemispherical projecting portion 22 which protrudes axially downward from the lower end portion of the tapered portion 21.

  A needle valve hole 23 for axially accommodating the needle valve 18 is formed in the center of the portion from the first portion 19 to the tapered portion 21 so as to extend in the axial direction. In addition, a suck chamber 24 communicated with the needle valve hole 23 is formed in the protrusion 22. A plurality of (four in the present embodiment) injection holes 25 which are fuel outlets are formed through the projection 22 at equal intervals in the circumferential direction. As well known, when the needle valve 18 is lowered, the tip of the needle valve 18 is pressed against the inner surface of the tapered portion 21 to stop the fuel supply to the injection hole 25 and the fuel injection is stopped. When the needle valve 18 ascends, the tip of the needle valve 18 is separated from the inner surface of the tapered portion 21 so that fuel is supplied to the injection hole 25 and fuel injection is performed. At this time, fuel is injected obliquely downward and radially into the combustion chamber 3 through the injection holes 25.

  The lower end of the first portion 19 and the upper end of the second portion 20 are connected in a step-like manner by the nozzle pressing surface 26 perpendicular to the axial direction. Further, the lower end of the second portion 20 and the upper end of the shaft portion 9 are connected in a step-like manner by a tapered surface 27 whose diameter decreases toward the lower side. The shaft portion 9 has a constant outer diameter D3 and extends in the axial direction by a predetermined length. The lower half portion of the tapered portion 21 formed at the lower end portion (tip portion) of the shaft portion 9 and the whole of the projecting portion 22 are positioned below the lower surface 14 of the cylinder head 1 and exposed in the combustion chamber 3 ing.

  The retaining nut 6 is a first fitting portion 28 fitted to the first portion 19 substantially without a gap and a second fitting fitted to the second portion 20 with a slight radial gap 29 therebetween. And a mating portion 30. The lower end of the inner circumferential surface of the first fitting portion 28 and the upper end of the inner circumferential surface of the second fitting portion 30 are connected in a step-like manner by a nut pressing surface 31 perpendicular to the axial direction. A gap between the nozzle body 17 and the radially inner side of the second portion 20 including the gap 29 is referred to as a nut inner gap, and is denoted by the same reference numeral 29 for convenience.

  The retaining nut 6 has an internal thread at an upper position outside the figure. When the female screw is tightened to the male screw of the valve body 4, the nut pressing surface 31 pushes up the nozzle pressing surface 26 to bring the nozzle body 17 into close contact with the upper valve body 4. Thus, the fuel injection nozzle 5 is integrally attached to the valve body 4.

  In the mounted state of the fuel injection valve 2 shown, a slight radial gap (referred to as a hole clearance) 32 is formed between the shaft 9 and the shaft insertion hole 13. A slight radial gap (referred to as a packing internal clearance) 33 is also formed between the packing 16 and the shaft 9. The in-hole gap 32 and the in-packing gap 33 and the above-mentioned in-nut gap 29 communicate with each other, and both communicate with the combustion chamber 3.

  The packing 16 is an annular toroidal member having a predetermined thickness t and extending around the entire circumference, and is fitted with a gap 33 on the radially outer side of the shaft 9. The packing 16 is sandwiched and fixed between the bearing surface 15 of the cylinder head 1 and the shoulder 10 of the fuel injection valve 2. The shoulder 10 is formed by the lower end of the second fitting portion 30 of the retaining nut 6. The lower end surface of the shoulder 10, that is, the lower end surface of the second fitting portion 30 of the retaining nut 6 is pressed against the upper surface of the packing 16.

  The usual packing generally used is a simple annular metal plate. On the other hand, the packing 16 of the present embodiment has a more complicated structure, and in addition to sufficient sealing performance, exhibits excellent heat transfer characteristics as described later. Hereinafter, the packing 16 of the present embodiment will be described in detail.

  As shown in FIG. 3, the packing 16 includes a packing body 41, a sealed cavity 42 formed inside the packing body 41, and a heat of a volume smaller than the volume of the cavity 42 enclosed in the cavity 42. And a liquid medium 43. The packing 16 further includes a reinforcing member 44 provided in the hollow portion 42 and sandwiched between the upper surface 47 and the lower surface 48 of the packing body 41.

  The packing main body 41 is made of a metal material (for example, copper) excellent in sealability and thermal conductivity. The packing main body 41 has a thickness t and a larger width w, and has a cross-sectional shape of a horizontally long rectangular and hollow box shape.

  The packing main body 41 is divided into an upper divided piece 45A and a lower divided piece 45B. The divided pieces 45A and 45B are fixed to each other at both end edges, ie, radially inner (right side in the drawing) and outer (left side in the drawing) end edges, or both width edges.

  In the present embodiment, the upper divided piece 45A is formed in a cross-sectional lid plate shape, and the lower divided piece 45B is formed in a cross-sectioned plate shape. After the upper split piece 45A is fitted to the lower split piece 45B, both split pieces 45A and 45B are fixed by welding at the fitting portion.

  The upper divided piece 45A is formed in an annular plate shape as a whole. The lower divided piece 45B is formed in an annular shape as a whole, and the cross section thereof is formed in an angular U-like shape whose upper side is opened. Both end edges of the lower divided piece 45B stand in the vertical direction, and stepped fitting holes 46, 46 are formed at the upper end portions thereof. The upper divided pieces 45A are inlay-fitted into the fitting holes 46 and 46, and the upper end opening of the lower divided pieces 45B is closed by the upper divided pieces 45A. After fitting, the fitting portion is fixed and sealed by welding such as brazing. As a result, a closed cavity 42 is formed inside the packing body 41. After fixing, the upper surfaces of the upper divided piece 45A and the lower divided piece 45B are arranged flush with each other.

  The heat transfer fluid 43 is formed of water, alcohol or a mixture thereof. The alcohol can be methanol or ethanol. The volume of the heat transfer fluid 43 is smaller than the volume of the cavity 42. As a result, the heat transfer fluid 43 is not filled in the cavity 42 as shown in the drawing, and in a normal state is accumulated by gravity at the bottom of the cavity 42 and touches the upper divided piece 45A forming the upper surface 47 of the packing main body 41 Absent. In other words, the liquid level of the heat transfer fluid 43 is positioned lower than the lower surface of the upper divided piece 45A. The volume of the heat transfer fluid 43 can be considerably smaller than the volume of the cavity 42, for example, 1/2 or less, 1/3 or less, 1/4 or less, or 1/5 or less of the volume of the cavity 42 And so on.

  The heat medium 43 is sealed, for example, by sealing the packing main body 41 in a heating vapor atmosphere of the heat medium 43. Therefore, the heat medium 43 is sealed in a state where the air is expelled.

  The reinforcing member 44 is provided to prevent crushing of the packing 16 when the packing 16 is pinched from above and below. The reinforcing member 44 is preferably made of a harder material than the packing body 41, for example made of stainless steel. The reinforcing member 44 is formed in an annular shape as a whole by a plate material, and has a rectangular shape whose cross section is vertically long. In the case of this embodiment, a plurality of (specifically, two) reinforcing members 44 are arranged in parallel in the width direction.

  After the reinforcing member 44 is positioned at a predetermined position in the hollow portion 42, the upper divided piece 45A is fitted and fixed to the lower divided piece 45B. Thereby, the reinforcing member 44 is sandwiched between the upper divided piece 45A and the lower divided piece 45B, and the position thereof is fixed. Alternatively or additionally, the reinforcing member 44 may be previously fixed in the cavity 42 by welding or the like.

  Thus, when the two reinforcing members 44 are provided, the inside of the cavity 42 is divided into three substantially widthwise spaces. The heat medium fluid 43 is sealed at the same level in each of these spaces. In addition, in order to maintain the liquid level of the heat medium 43 in each space more positively and equally, the reinforcing member 44 may be provided with a communication hole for communicating adjacent spaces.

  Next, the operation and effect of the present embodiment will be described.

  For example, it is assumed that the engine is stopped and the engine is started from the cold state at a place where the outside air temperature is low, such as a cold area. In this case, the cylinder head 1 and the fuel injection valve 2 which are sufficiently low in temperature are heated by the combustion gas in the combustion chamber 3 and the temperatures of both increase gradually.

  During operation of the engine, water vapor and fine water droplets contained in combustion gas and intake air (including EGR gas and blowby gas) sequentially infiltrate from the combustion chamber 3 into the hole gap 32, the packing gap 33, and thus the nut gap 29. I will. In particular, water vapor and the like in the combustion chamber 3 is pushed into the inter-hole gap 32 and the like when the in-cylinder pressure rises, and water vapor and the like in the combustion chamber 3 gradually infiltrates the inter-hole gap 32 and the like Water vapor or the like tends to infiltrate into the in-hole space 32 or the like and tends to stagnate because it is difficult for the in-hole space 32 or the like to be narrow and the water vapor or the like that has entered once is difficult to escape.

  Next, when the engine is stopped within a short time after the start (referred to as an immediate stop operation after start), the cylinder head 1 and the fuel injection valve 2 are rapidly cooled by the outside air, and eventually the fuel injection facing the in-hole gap 32 The temperature of the surface of the shaft portion 9 of the valve 2 falls below the dew point temperature, and water vapor and the like in the hole gap 32 condenses to form dew condensation on the surface, generating dew condensation water on the surface. The condensation water may cause damage such as rusting or corrosion of the surface of the shaft 9. The problem of this damage similarly occurs on the surface of the fuel injection valve 2 facing the gap 33 in the packing and the gap 29 in the nut.

  On the other hand, dew condensation water may be generated similarly on the inner peripheral surface of the shaft insertion hole 13 facing the shaft 9. However, the inner peripheral surface is formed in a relatively thick cylinder head 1, the cylinder head 1 is formed of a lightweight and corrosion-resistant metal material, specifically aluminum, and the cylinder head 1. Due to the fact that the oxide film has already been formed on the surface of the surface, the generation of dew condensation water on the inner peripheral surface is practically not a problem. In addition, dew condensation water may similarly be generated on the inner peripheral surface of the second fitting portion 30 of the retaining nut 6 facing the gap 29 in the nut. However, since the entire surface of the retaining nut 6 is subjected to a surface treatment for anticorrosion, the generation of dew condensation water on the inner circumferential surface does not practically cause any problem.

  The nozzle body 17 is not subjected to such surface treatment, and is used in a state where iron as a material is exposed. Moreover, the axial portion 9 is relatively thin. Therefore, rust or corrosion is likely to occur, and if it occurs, it may lead to secondary damage such as cracking in a short period of time. Therefore, measures against such condensation water are very important.

  Therefore, in the present embodiment, the packing 16 as described above is used. Using this, it is possible to improve the behavior of heat during engine operation and shutdown as follows.

  That is, when the engine is started from the cold state, the cylinder head 1 and the fuel injection valve 2 are heated by the combustion gas and the temperature is raised. At this time, as shown by arrow a in FIG. 4, the heat of the cylinder head 1 is sequentially transmitted from the bearing surface 15 to the lower surface portion 48 and lower surface portion 48 of the packing main body 41 to the heat medium 43, and the heat medium 43 is It is heated and evaporated. The vapor of the heat transfer fluid 43 rises and contacts the upper surface 47 of the packing main body 41 to heat the upper surface 47. Thus, heat flows from the heat transfer fluid 43 to the upper surface 47 and from the upper surface 47 to the shoulder 10 of the fuel injection valve 2, and the packing 16 positively transfers the heat of the cylinder head 1 to the fuel injection valve 2. And promote the heating of the fuel injection valve 2.

  The vapor of the heat transfer fluid 43 in contact with the upper surface portion 47 of the packing main body 41 is deprived of heat by the upper surface portion 47, and is condensed and liquefied. Then, the liquefied vapor is dropped by the action of gravity and returned to the bottom of the cavity 42. As a result, a circulation cycle of the heat medium 43 which continuously reciprocates between the bottom and the top of the hollow portion 42 is generated. The vibration of the engine also favors the fall of the liquefied vapor. This is because the lump of liquefied vapor adhering to the upper surface portion 47 can be separated by vibration.

  Next, when the engine is stopped within a short time after the start (when the immediate stop operation is performed after the start), the cylinder head 1 and the fuel injection valve 2 are rapidly cooled by the outside air. At this time, the cylinder head 1 is formed of aluminum having a high thermal conductivity, and the engine is stopped before the cooling water in the water jacket (not shown) formed inside the cylinder head 1 has not warmed up yet. The temperature of the cylinder head 1 tends to decrease more rapidly than the temperature of the fuel injection valve 2 due to reasons such as failure.

  Meanwhile, at this time, the packing 16 is also cooled, and the temperature of the heat medium 43 inside the packing 16 is lowered. For this reason, almost all the vapor of the heat transfer fluid 43 is liquefied, and as shown in FIG. 3, the heat transfer fluid 43 becomes almost all liquid and accumulates at the bottom of the cavity 42.

  In this case, a low pressure layer in the hollow portion 42 is formed between the upper surface portion 47 of the packing main body 41 and the heat medium fluid 43, and this low pressure layer becomes a heat insulating layer. The flow of heat flowing to it is significantly suppressed.

  As a result, the cooling and temperature decrease of the fuel injection valve 2 can be suppressed, and the temperature of the fuel injection valve 2 can be maintained at a relatively high temperature, thereby suppressing the generation of condensation water at the condensation water generation location of the fuel injection valve 2 It is possible to reliably suppress damage such as rust and corrosion caused by water. Here, the dew condensation water generation location is mainly the surface of the shaft portion 9 that faces the in-hole gap 32. However, secondarily, the surface of the shaft 9 facing the gap 33 in the packing, and the surface of the shaft 9 facing the gap 29 in the nut, the tapered surface 27 and the second portion 20 are also included in the condensation water generation location. Be

  As described above, according to the packing 16 and the mounting structure of the present embodiment, it is possible to provide a thermal diode that allows the flow of heat from the cylinder head 1 to the fuel injection valve 2 while blocking or suppressing the flow in the reverse direction. Can. Further, when the immediate stop operation after start is performed, the temperature decrease of the fuel injection valve 2 can be delayed from the temperature decrease of the cylinder head 1 and the temperature of the fuel injection valve 2 can be maintained higher than the temperature of the cylinder head 1. As a result, dew condensation can be generated exclusively on the cylinder head 1 side, and the occurrence of dew condensation on the fuel injection valve 2 side can be suppressed accordingly. For the above reasons, condensation on the cylinder head 1 side is practically not a problem, and by suppressing the occurrence of condensation on the fuel injection valve 2 side, it is possible to solve the problem caused by condensation at once. is there.

  In the case of a normal packing made of a simple metal plate, the heat of the fuel injection valve is actively transmitted to the cylinder head through the packing when the immediate stop operation is performed after the start, so the fuel injection valve Decreases at a speed equal to or faster than that of the cylinder head. In such a case, dew condensation occurs a lot on the fuel injection valve side, and the above problem occurs.

  By the way, in the present embodiment, since the reinforcing member 44 is provided, crushing of the packing 16 can be reliably suppressed. The reinforcing member 44 stretches between the upper surface portion 47 and the lower surface portion 48 to prevent the packing 16 from being deformed or crushed in the thickness t direction. In addition, regarding the modification, the number of reinforcing members 44 may be changed to one or three or more. The shape (including the cross-sectional shape) of the reinforcing member 44 may be changed, and for example, the cross-sectional shape may be tapered. If the rigidity of the packing main body 41 is sufficient, the reinforcing member 44 may be omitted.

  Further, since the packing main body 41 is divided into the upper divided pieces 45A and the lower divided pieces 45B and the divided pieces 45A, 45B are fixed at both end edges, the divided pieces 45A, 45B can be formed of plate members appropriately processed and easily It is possible to form the cavity 42 which is reliably sealed by assembly.

  Since the split pieces 45A and 45B are fixed to each other by welding, both can be assembled easily and reliably.

  In particular, the upper split piece 45A is formed in a cross-sectional lid plate shape, the lower split piece 45B is formed in a cross-sectional dish shape, the upper split piece 45A is fitted to the lower split piece 45B, and the fitting portion is fixed by welding. did. As a result, both can be assembled easily and reliably, and the cavity 42 can be formed easily and reliably sealed. The mode of fitting is not limited to the in-row fitting.

  Since the heat transfer fluid 43 is formed of water, alcohol or a mixture thereof, the heat transfer fluid 43 can be formed of an inexpensive material that can be easily obtained.

  Next, modifications of the packing will be described. The same parts as those in the basic example described above are denoted by the same reference numerals in the drawings, and a description thereof will be omitted. Hereinafter, differences from the basic example will be mainly described.

  As shown in FIG. 5, the packing 16 </ b> A of the modification also includes a packing main body 41, a hollow portion 42, a heat medium fluid 43, and a reinforcing member 44. The packing body 41 has a thickness t and a larger width w, and is divided into an upper divided piece 45A and a lower divided piece 45B. The divided pieces 45A and 45B are fixed to each other by caulking at both end edges.

  The upper divided piece 45A and the lower divided piece 45B are formed in a cross-sectional shape that is substantially vertically symmetrical. Both end edges of the upper divided piece 45A and the lower divided piece 45B are bent in a substantially S shape or a substantially crank shape so as to be in close contact and in surface contact with each other at the central portion in the thickness t direction. Both end edges of the lower divided piece 45B are longer in the width w direction than both end edges of the upper divided piece 45A. Then, both end edges of the lower divided piece 45B protruding in the width w direction from both end edges of the upper divided piece 45A are crimped to both end edges of the upper divided piece 45A as illustrated. As a result, caulking portions 50, 50 are formed on both end edges of the packing main body 41. At the time of caulking, the protruding portions at both end edges of the lower divided piece 45B are folded back 180 ° so as to overlap the upper surfaces of both end edges of the upper divided piece 45A, and simultaneously pressed against the upper and lower surfaces of the upper divided piece 45A. At the same time as the packing body 41 is completed, a closed cavity 42 is formed therein.

  As in the basic example, the heat medium 43 and the plurality (two) of the reinforcing members 44 are formed in advance between the upper split piece 45A and the lower split piece 45B (particularly, above the lower split piece 45B) before caulking. Be placed.

  Thus, even if the split pieces 45A and 45B are fixed by caulking, it is possible to facilitate the assembly of the packing main body 41. In addition to or instead of caulking, welding may be performed.

  Although the embodiments of the present disclosure have been described in detail above, the present disclosure can be other embodiments as follows.

  (1) For example, the material of the heat transfer fluid may be other than water, alcohol or a mixture thereof, and the alcohol may be other than methanol or ethanol. The optimum material can be selected based on the results of the actual machine test and the like.

  (2) The structure of the packing main body is not limited to the above, and may be, for example, a single hollow structure which is not a divided structure. In this case, the packing body may be provided with a hole for sealing the heat transfer fluid, and after sealing, the hole may be closed.

  (3) An embodiment without at least one of the packing internal gap 33 and the nut internal gap 29 is also possible.

  FIG. 6 shows another embodiment in which there is no gap 33 in the packing. In this case, the packing 16 is in contact with the shaft 9 of the fuel injection valve 2. Specifically, the inner circumferential surface portion 51 of the packing main body 41 is in contact with the outer circumferential surface of the shaft portion 9. In the present embodiment, the inner diameter of the packing main body 41 is equal to the outer diameter D3 of the shaft 9, and the inner peripheral surface 51 of the packing main body 41 is in full circumferential contact with the outer peripheral surface of the shaft 9. However, only a part in the circumferential direction may be in contact.

  According to this, during the operation after the start of the engine, the shoulder 10 can be heated through the same route as indicated by the arrow a, and the steam of the heat medium 43 shown by the arrow b → the inner circumferential surface 51 → The shaft 9 can be directly heated through the path of the shaft 9. Thus, the heating of the shaft 9 can be promoted.

  In addition, since the steam of the heat transfer fluid 43 is liquefied when it is immediately stopped after starting, as shown by the arrow c, the shaft portion 9 → inner peripheral surface 51 → steam of the heat transfer fluid 43 → heat transfer fluid 43 There is virtually no route. Accordingly, the cooling of the shaft 9 can be suppressed, and the temperature can be maintained at a relatively high temperature to suppress the generation of dew condensation water.

  (4) The packing and the mounting structure according to the present disclosure are useful even in the cold district or the like except for the case of immediate stop operation after start. Even in such a case, if the engine is started and then stopped, dew condensation may occur on the shaft portion of the fuel injection valve.

  (5) The cylinder head is not limited to aluminum, and the material is arbitrary. For example, it may be made of iron. Further, the retaining nut 6 may not be subjected to the surface treatment for rust prevention.

  (6) In the said embodiment, the example of arrangement | positioning of the fuel injection valve 2 which valve-shaft C follows a perpendicular direction was demonstrated. However, the arrangement example of the fuel injection valve 2 is not limited to this, and for example, the fuel injection valve 2 is arranged so that the valve shaft C is inclined with respect to the vertical direction according to the specification of the engine It does not matter. Also, the valve axis C may be non-coaxial or non-parallel to the cylinder axis.

  The embodiment of the present disclosure is not limited to the above-described embodiment, and all variations, applications, and equivalents included in the concept of the present disclosure defined by the claims are included in the present disclosure. Accordingly, the present disclosure should not be construed as limiting, and can be applied to any other technology falling within the scope of the present disclosure.

Reference Signs List 1 cylinder head 2 fuel injection valve 16 packing 41 packing main body 42 hollow portion 43 heat medium fluid 44 reinforcing member 45A upper divided piece 45B lower divided piece

Claims (8)

A packing adapted to be placed between a cylinder head of an internal combustion engine and a fuel injection valve, the packing comprising:
Packing body,
A closed cavity formed inside the packing body;
Heat solvent having a volume smaller than the volume of the cavity enclosed in the cavity;
Packing characterized by having. The packing according to claim 1, further comprising a reinforcing member provided in the hollow portion and sandwiched between an upper surface portion and a lower surface portion of the packing main body. The packing according to claim 1 or 2, wherein the packing main body is divided into an upper divided piece and a lower divided piece, and the divided pieces are fixed to each other at both end edges. The packing according to claim 3, wherein the divided pieces are fixed to each other by welding or caulking. The upper divided piece is formed in a lid plate shape in cross section, the lower divided piece is formed in a dish shape in cross section, the upper divided piece is fitted in the lower divided piece, and the fitting portion is fixed by welding The packing according to claim 3. The packing according to any one of claims 1 to 5, wherein the heat transfer fluid is formed of water, an alcohol or a mixture thereof. An attachment structure for airtightly attaching a fuel injection valve to a cylinder head of an internal combustion engine,
A shaft insertion hole provided in the cylinder head;
A seating surface provided on the cylinder head and formed around the shaft insertion hole;
A shaft portion provided in the fuel injection valve and inserted into the shaft insertion hole with a radial gap therebetween;
A shoulder provided on the fuel injection valve and formed around the shaft;
A packing disposed between the seat and the shoulder;
Equipped with
The packing is
Packing body,
A closed cavity formed inside the packing body;
Heat solvent having a volume smaller than the volume of the cavity enclosed in the cavity;
Mounting structure characterized by comprising. The mounting structure according to claim 7, wherein the packing is in contact with the shaft portion.

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