JP2014055537A - Fuel injection device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection device for an internal combustion engine, which has a seal structure usable in high pressure, in a connection part between a fuel pipe and a fuel injection valve.SOLUTION: A fuel injection device for an internal combustion engine includes a fuel injection valve which supplies fuel into the internal combustion engine, and has a construction which seals a gap between the fuel injection valve and a fuel pipe 101 by using an elastic member. The fuel injection device includes an insertion hole which internally accommodates a connection part of the fuel pipe 101. The elastic member is provided internally on the fuel injection valve or externally on the fuel pipe 101.

Description

The present invention relates to a fuel injection device for injecting and supplying fuel to an internal combustion engine, and more particularly to a fuel injection device suitable for use in an internal combustion engine in which high-pressure fuel is directly injected and supplied to a combustion chamber, such as an in-cylinder fuel injection internal combustion engine. .

In recent years, an in-cylinder fuel injection type in which fuel is directly injected into a combustion chamber has been put into practical use in an internal combustion engine such as an in-vehicle engine for the purpose of improving fuel consumption. In such an in-cylinder fuel injection type internal combustion engine, fuel is injected into the combustion chamber in a high pressure state. Therefore, the fuel is pressurized to a high pressure by a pump and pumped to the fuel pipe, and then the fuel injection connected to the fuel pipe. Fuel is directly injected from the valve into the combustion chamber.
The following system is disclosed as a connection system between the fuel pipe of such a high-pressure fuel supply device and the fuel injection valve.
First, Japanese Patent Laid-Open No. 2009-62859 discloses a structure in which a connecting portion between the fuel pipe and the fuel injection valve is sealed by an elastic seal member such as an O-ring.
Further, in Japanese Patent No. 3385415, a high-pressure fuel pipe is connected by surface-contacting a tapered pipe end portion at a high pressure, and the high-pressure fuel pipe is made of an inner tube made of stainless steel and a softer steel material than this. The outer tube is integrated, and the soft material is plastically deformed by bringing only the outer tube into surface contact with the divergent recess formed at the rim of the fuel inlet / outlet of the high-pressure fuel system equipment. A method for improving the fuel sealability by adapting the connecting portion is disclosed.

JP 2009-62859 A JP 2011-169243 Japanese Patent No. 3385415

FIG. 19 shows an example of a general structure (for example, Japanese Patent Application Laid-Open No. 2009-62859) in which a connection portion between a fuel pipe and a fuel injection valve is sealed with an O-ring. In this connection portion, an O-ring 103 and a backup ring 104 that are seal rings are attached to the fuel injection valve, and the fuel injection valve is fitted into the fuel pipe 101 via these seal rings.
For this reason, in the same connection portion, the connection end surface between the fuel injection valve and the fuel pipe 101 becomes a pressure receiving surface A1 for the fuel pressure P in the fuel pipe 101, and the force due to the fuel pressure P is applied to the pressure receiving surface A1. The fuel injection valve will work in a direction to escape from the fuel pipe.
When the fuel pressure is supplied from the fuel pipe 101, the O-ring 103 is attached to the fixed ring 105 provided at the joint portion of the fuel injection valve via the backup ring 104 by the fuel pressure inside the fuel pipe 101 of the fuel injection valve. Pressed. As a result, the fuel injection valve receives a force in a direction to be pushed out below the fuel pipe 101. This force is received by the fixing clip 102 and the pressing plate 106 between the fixing ring 105 and the fixing protrusion 123 provided at the joint portion of the fuel pipe 101 to prevent the fuel injection valve from being pushed out.
As a result, a load is applied corresponding to the fuel pressure of the fixing clip 102 and the pressing plate 106 which are fastening members, the fixing ring 105 and the fixing protrusion 123 which are joint portions of the fuel injection valve and the fuel pipe. For this reason, the joint part of the fastening member, the fuel injection valve, and the fuel pipe needs to have a sufficiently strong structure against the force caused by the fuel pressure, which may increase the cost.
In addition, in order to cope with future exhaust gas regulations and small displacement internal combustion engines with turbochargers that will rapidly spread in the future, multistage injection, high atomization, and high output are required, and fuel pressure tends to further increase is there.
For this reason, it is necessary to reduce the load on the fuel pipe, the fuel injection valve, and the fastening member. As a countermeasure, it is necessary to reduce the force due to the fuel pressure, and it is effective to reduce the seal diameter of the joint portion between the fuel pipe of the fuel passage and the fuel injection valve to reduce the area of the pressure receiving surface A1.
However, in order to reduce the O-ring wire diameter, the positional accuracy between the fuel injection valve and the fuel pipe is limited in order to secure the necessary compression amount of the O-ring. Therefore, in order to reduce the seal diameter, it is necessary to reduce the O-ring inner diameter together with the O-ring outer diameter.

In order to solve the above-mentioned problems, a fuel injection valve for an internal combustion engine having a fuel injection valve for injecting and supplying fuel to the internal combustion engine and having a structure in which a gap between the fuel injection valve and a fuel pipe is sealed using an elastic member In the apparatus, the fuel injection valve has an insertion hole that encloses a connection portion of the fuel pipe, and the elastic member is configured to be internal to the fuel injection valve or external to the fuel pipe.

According to the present invention, since the O-ring is disposed inside the fuel injection valve, the inner diameter of the O-ring can be reduced, the pressure receiving area of the O-ring can be reduced, and the force applied to the fastening member, the fuel injection valve, and the fuel piping can be reduced. It can be reduced.

It is sectional drawing which shows the whole fuel-injection apparatus which concerns on the 1st Example of this invention. It is a perspective view which shows the components structure of the fuel injection apparatus which concerns on this invention. It is a perspective view which shows the assembly state of the fuel-injection apparatus which concerns on this invention. It is an expanded sectional view in the fuel injection valve and fuel piping connection part vicinity which concerns on this invention. It is sectional drawing which shows the force, moment, and deformation | transformation which generate | occur | produce in the fuel injection valve which concerns on this invention, and fuel piping connection part vicinity. FIG. 4 is an enlarged cross-sectional view before the force, moment, and deformation generated in the fuel pipe and the minute protrusion according to the present invention. FIG. 4 is an enlarged cross-sectional view after the force, moment, and deformation generated in the fuel pipe and the minute protrusion according to the present invention. It is a perspective view which shows the components structure of the fuel-injection apparatus which concerns on the 2nd Example of this invention. It is an expanded sectional view in the fuel injection valve and fuel piping connection part vicinity which concerns on the 2nd Example of this invention. It is an expanded sectional view in the fuel injection valve and fuel piping connection part vicinity which concerns on the 3rd Example of this invention. It is an expanded sectional view in the fuel injection valve and fuel piping connection part vicinity which concerns on 1st Example of this invention, Comprising: It is a figure which shows the example which provided the processus | protrusion on the side of the pressing board. It is the figure which looked at the pressing plate 901 from the side of the fixing ring 903. It is an expanded sectional view in the fuel injection valve and fuel pipe connection part vicinity which concerns on the 4th Example of this invention. It is an expanded sectional view in the fuel injection valve and fuel pipe connection part vicinity which concerns on 4th Example of this invention, Comprising: It is a figure which shows the example which made the contact part with the fixing ring 1104 of a pressing plate into the taper shape. It is an expanded sectional view in the fuel injection valve and fuel pipe connection part vicinity which concerns on the 5th Example of this invention. It is an expanded sectional view in the fuel injection valve and fuel piping connection part vicinity which concerns on 5th Example of this invention, Comprising: It is a figure which shows the example which made the O-ring seal surface of the core of the fuel injection valve spherical shape. FIG. 6 is a perspective view of the pressing plate 1101 as viewed from the fixing ring 1104 side. 1 is an enlarged cross-sectional view in the vicinity of a fuel injection valve and a fuel pipe connection part according to the first embodiment of the present invention, and an example in which a protrusion for preventing the O-ring and the backup ring from dropping off is provided on the core side of the fuel injection valve. FIG. FIG. 2 is an enlarged cross-sectional view in the vicinity of a fuel injection valve and a fuel pipe connection portion according to the first embodiment of the present invention, and an example in which a member for preventing the O-ring and the backup ring from dropping is attached to the core side of the fuel injection valve. FIG. It is an expanded sectional view in the fuel injection valve and fuel pipe connection part vicinity which concerns on the 6th Example of this invention. It is an expanded sectional view in the fuel injection valve and fuel piping connection part vicinity which concerns on the Example of a prior art.

 Embodiments of a fuel injection valve according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this Example.

FIG. 1 is a cross-sectional view of a fuel injection device according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a state in which the fuel pipe 101, the fixing clip 102, the holding plate 106, and the fuel injection valve are disassembled, and FIG. 3 is a perspective view in a state in which these are assembled. FIG. 4 is an enlarged cross-sectional view of a connection portion between the fuel injection valve and the fuel pipe 101.

  FIG. 1 shows a fuel pipe 101 connecting a high-pressure fuel pipe main body and a fuel injection valve, a fixing clip 102 and a holding plate 106 used for the connection, an O-ring 103 used for a fuel seal, its backup ring 104, an O-ring 103 and its A retaining projection 122 for holding the backup ring 104 in the fuel pipe is shown.

  When the fuel pressure is applied via the fuel pipe 101, the O-ring 103 is provided at the joint portion of the fuel injection pipe 101 via the backup ring 104 by the fuel pressure at the connection with the fuel pipe 101 of the fuel injection valve. Pressed against the fixed ring 105. As a result, the fuel injection valve receives a force in a direction in which the fuel injection valve is pushed downward (arrow a) of the fuel pipe 101. This force is received by the fixing clip 102 and the pressing plate 106 between the fixing ring 105 and the fuel injection valve from being pushed out.

  By adopting such a structure, since the O-ring 103 is attached to the inside of the fuel injection valve, the inner diameter of the O-ring 103 can be reduced regardless of the outer diameter of the internal components such as the spring 107 of the fuel injection valve. As a result, the pressure receiving area is reduced by reducing the outer diameter of the O-ring, and the strength of the fastening member abutting portion between the fastening clip 102 and the holding plate 106 and the fuel injection valve and the fuel pipe is reduced. Can do.

  Here, the tip of the fuel injection valve provided with the combustion gas seal member 119 is inserted into a mounting hole provided in the engine head, and the tip of the fuel injection valve is positioned at the position of the arrow 121 in the portion of the combustion gas seal member 119. Fixed to the head. For this reason, if there is an eccentricity between the mounting hole of the engine head and the fuel pipe 101, for example, a force in the direction shown by the arrow 121 is received from the engine head, and the fuel injection valve receives a bending moment. Become.

  Since the fixing clip 102 and the holding plate 106 that fix the fuel injection valve are not damaged even when the fuel injection valve is pressed by the fuel pressure, a material having high strength is used. For this reason, the fuel injection valve is pressed against the pressure plate 106 by the fuel pressure under a condition where the fuel pressure is applied, and is firmly fastened to the fuel pipe 101 via the fixing clip 102.

  In the fuel injection valve, a member that opens and closes is provided on the downstream side of the adjuster pin 120 and the spring 107. The fuel injection valve is a device that starts and stops fuel injection by opening and closing the valve body 113. The valve body 113 slides while being guided by the upstream rod guide 112 and the valve body guide 115 provided on the downstream side. These guide members are fixed to the nozzle holder 114.

  The driving force for opening the valve body 113 is transmitted through the contact portion 124 between the anchor 111 and the valve body 113 by a magnetic attraction force generated between the anchor 111 and the core 110 by energizing the coil 108. . The driving force for closing the valve body 113 is a force by the spring 107 biased in the compression direction by the adjuster 120. For this reason, when energization of the coil 108 is stopped, the valve element 113 moves in the valve closing direction by the urging force of the spring 107 and closes in contact with the valve seat provided on the orifice plate 116.

  Since the fuel injection valve has the above-described structure, when the downstream portion of the adjuster pin 120 such as the nozzle holder 114, the housing 109, and the core 110 is deformed, the position of the rod guide 112 or the valve body guide 115 is shifted. And the operation of the valve body 113 may be different from the operation before the deviation occurs.

  Therefore, a description will be given with reference to FIG. In the first embodiment according to the present invention, a minute protrusion 401 is provided at a portion where the fixing ring 105 and the pressing plate 106 abut.

  The member forming the fixing ring 105 may be a member that is softer (that is, has a lower yield point) than the fixing clip 102 and the pressing plate 106, such as ferritic stainless steel or austenitic stainless steel. By adopting such a configuration, the effects described later are obtained and deformation of the fuel injection valve is prevented. Since the fixing ring 105 is preferably made of a softer material than the pressing plate 106 and the fixing clip 102, the thickness of the fixing ring 105 in the upstream and downstream direction of the fuel injection valve is determined by the thickness of the pressing plate 106 and the fixing clip. It is desirable that the thickness be greater than 102. With such a thickness relationship, any destruction of the fixing clip 102, the pressing plate 106, and the fixing ring 105 can be prevented.

  In FIG. 4, a minute protrusion 401 is provided on the fixing ring 105 side of the surface where the pressing plate 106 and the fixing ring 105 abut. Since the microprojection 401 has a lower yield point than the pressing plate 106 that abuts the fixing ring 105, when the microprojection 401 receives a large force, it deforms plastically before the pressing plate 106.

  FIG. 5 a is a diagram illustrating a relationship between the state in which the minute protrusion 401 is plastically deformed on the contact surface with the pressing plate 106 and the force received by each member. In FIG. 5a, the state where the fuel injection valve is tilted and attached is depicted, but the magnitude of the tilt is depicted larger than the actual one. The fuel injection valve receives a force indicated by an arrow 501 depending on the fuel pressure. On the other hand, when the force indicated by the arrow 502 is received by the fixing ring 105, the holding plate 106, and the fixing clip 102, the fuel injection valve is fixed to the fuel pipe 101. As a result, the minute protrusion 401 provided on the fixing ring 105 receives the force indicated by the arrow 502 by the pressing plate 106 by the fuel pressure.

  Here, as shown in FIG. 1, in the vicinity of the tip of the fuel injection valve, there is an eccentricity in the hole of the engine head into which the combustion gas seal member 119 serving as a fixing portion between the fuel pipe 101 and the engine head is inserted. In this case, the fuel injection valve receives a force generated by forced displacement as indicated by an arrow 121. For this reason, a bending moment as shown by an arrow 503 in FIG. As a result, the minute protrusion 401 receives a resultant force of the force due to the fuel pressure (arrow 502) and the force that receives the bending moment indicated by the arrow 503.

  Here, since the minute protrusion 401 is made of a material having a yield point lower than that of the pressing plate 106, the minute protrusion 401 is plastically deformed before the pressing plate 106 yields. Such plastic deformation has a large amount of deformation at a portion where the resultant force of the force generated by the bending moment generated in the fuel injection valve and the force due to the fuel pressure is large. As a result, the fuel injection valve itself is inclined and attached due to the bending moment generated by the forced displacement. In this way, the amount of forced displacement input by eccentricity is absorbed by the inclination of the fuel injection valve. As a result, the bending moment generated in the fuel injection valve is reduced. Here, the minute protrusion 401 is preferably formed in a tapered shape between the bottom surface and the upper surface of the protrusion. This is because, as shown in FIGS. 5b and 5c, the contact area is increased in the process of plastic deformation of the microprotrusions, and the moment supporting force can be gradually increased. In other words, the force applied to the fuel injection valve can be distributed to the fuel pipe.

  Further, since there is a portion in the fuel pipe 101 that absorbs the relaxation of the bending moment by deformation, such as the minute protrusion 401, the distance L (shown in FIG. 1) from the point where the forced displacement is input can be increased. The amount of displacement at the point subjected to the forced displacement indicated by the arrow 121 can be relaxed with a slight deformation amount of the minute protrusion 401. Further, since the fuel pipe 101 has a deformable portion, the bending moment accompanying the forced displacement can be reduced without affecting the fuel injection valve that is a functional component.

  Therefore, even if the fuel injection valve is forcedly displaced in the direction indicated by the arrow 121 as shown in FIG. 1, the microprojections 401 are locally plastically deformed to relieve the bending moment, and the fuel injection valve is deformed. Can be prevented. Therefore, even if the fuel pipe 101 and the fuel injection valve mounting hole provided in the engine head are eccentric from each other, the fuel injection valve can be mounted without impairing the function of the fuel injection valve. Moreover, the strength of the pressing plate 106 and the fixing clip 102 can be increased by selecting a material so that the yield point of the pressing plate 106 and the fixing clip 102 is larger than the yield point of the minute protrusion 401 portion. The strength can be maintained even with a high fuel pressure. Further, by limiting the deforming portion to the minute protrusion 401, it is possible to design the fixing ring 105 to be sufficiently thick so that the fixing ring 105 is not damaged.

  In this way, even when the fuel injection valve is fixed to the fuel pipe 101, the fuel pipe 101 and the fuel injection valve mounting hole of the engine head are not offset while the strength of the holding plate 106 and the fixing clip 102 is sufficiently maintained. The function of the fuel injection valve is not impaired by the wick. Further, since the plastically deformable minute protrusion 401 is provided at a site different from the fuel seal portion, the plastic deformation generated in the minute protrusion 401 affects the fuel sealability (leakage prevention). Never give. Further, since it is not necessary to reduce the thickness of the fuel passage portion, the present invention can also be applied to an in-cylinder direct injection engine that requires a relatively high fuel pressure. In this way, it is possible to reduce the possibility that the eccentricity between the fuel pipe and the mounting hole of the fuel injection valve on the engine head side causes fuel leakage due to deformation or breakage of the material.

  In addition, the above effects can also be obtained by providing the minute projections 902 on the side of the pressing plate 901 as shown in FIG. Even when the minute protrusion 902 is provided on the holding plate 901, the side of the fixing ring 903 made of a soft material is plastically deformed, and the same operation and effect as in the case of FIG. Can be obtained.

  In any case, it is not always necessary to provide the minute protrusions continuously in the circumferential direction. For example, FIG. 10 shows an example in which the pressing plate 901 is viewed from the side of the fixing ring 903, and is an example in which protrusions are provided on the pressing plate side, and minute projections 902 are provided discontinuously in the circumferential direction. This makes it possible to sufficiently increase the surface pressure even when it is difficult to make the microprotrusions have a sufficiently small width. Therefore, the soft material side is plastically deformed, and the fuel injection on the fuel pipe and the engine head side is performed. It absorbs the forced displacement caused by the eccentricity of the valve mounting hole and reduces the bending moment.

  In the above embodiment, the backup ring 104 and the O-ring 103 are attached so as to enclose the fuel pipe 101 before the fuel pipe 101 is inserted into the core 110 of the fuel injection valve. Although the structure of suppressing and holding in the pipe 101 is shown, a structure in which the backup ring 104 and the O-ring 103 are included and held in the core 110 of the fuel injection valve may be used.

As shown in FIG. 16, a retaining protrusion 1601 for preventing the backup ring 104 and the O-ring 103 from falling off is provided on the inner peripheral surface of the core 110 of the fuel injection valve above the contact portion of the backup ring.
Note that the retaining protrusion 1601 is not necessarily provided continuously in the circumferential direction. Further, the retaining protrusion 1601 may be a separate member that can be attached and detached.
In FIG. 17, a groove is provided on the inner peripheral surface of the core 110 of the fuel injection valve above the contact portion of the backup ring, and a detachable retaining member 1701 for preventing the backup ring 104 and the O-ring 103 from falling off is provided. . For example, a C-ring may be used as the retaining member 1701.

  As described above, according to the present embodiment, the fuel injection valve is attached to the fuel pipe which is a fixing method for preventing the sound accompanying the operation of the fuel injection valve from propagating to the engine head without impairing the function of the fuel injection valve. A fixing method can be adopted. Further, at this time, it is not necessary to use fuel pipes or the like made with extremely high accuracy, and a significant increase in cost can be suppressed.

FIG. 6 is a perspective view showing an example in which a plastically deformable portion is detachable in the embodiment according to the present invention. This is an example in which a substantially horseshoe-shaped plate member 601 having a yield point smaller than that of the pressing plate 106 is inserted between the pressing plate 106 and the fuel injection valve. FIG. 7 is a cross-sectional view of the vicinity of the attachment position of the fuel pipe 101 and the fuel injection valve in a state where the plate-like member 601 is inserted, and is a view seen from the connector 201 (shown in FIG. 6).
Since the plate-like member 601 exhibits the same function as the protrusion 401 in the first embodiment, the same effect as that of the first embodiment can be obtained in the second embodiment. In addition, since the plate member 601 has a substantially horseshoe shape, the plate member 601 can be inserted in the process of assembling the fuel injection valve to the fuel pipe.
By making the member capable of plastic deformation different from the fuel injection valve, plastic deformation of the fuel injection valve main body can be prevented. As a result, for example, even when a fuel injection valve or piping is removed, the fuel injection valve main body is not deformed. Therefore, only the plate member 601 needs to be replaced. When such a usage method is adopted, it is desirable that the yield point of the plate member 601 is not only smaller than the material used for the pressing plate 106 but also smaller than the material constituting the fixing ring 105. By setting the magnitude relationship between the yield points, the desired effect can be obtained without damaging both the fuel injection valve and the holding plate 106.

FIG. 8 is a cross-sectional view showing a third embodiment according to the present invention, and is an enlarged view of the vicinity of the attachment portion of the fuel pipe 101 and the fuel injection valve. In the third embodiment, a corner R802 is provided at a corner on the side where the pressing plate 801 contacts the fixing ring 804, and a corner R803 is provided at a portion where the fixing ring 804 contacts the pressing plate 801. The corner R802 is provided to be smaller than the corner R803. In this way, the corner R is provided in the fixing ring 804 on the fuel injection valve side, and the corner R is provided on the side of the holding plate 801 that is a member used for fixing to the fuel pipe 101, so that the contacted portion is in a line contact state. It becomes. Even in the case of line contact, the stress at the contact portion increases, and the fixing ring 804 side made of a soft material is plastically deformed. In addition, since the corner R802 is set smaller than the corner R803, even when the fuel pipe 101 and the mounting hole on the engine head side are eccentric, the same as the minute projection shown in the first embodiment. The fuel injection valve itself can be inclined to absorb the bending moment.

FIG. 11 is a cross-sectional view showing a fourth embodiment according to the present invention, and is an enlarged view of the vicinity of the fuel pipe 101 and the fuel injection valve mounting portion. In this embodiment, the surface 1103 on which the fixing ring 1104 contacts the holding plate 1101 has a spherical shape that curves downward toward the fuel injection valve toward the outer periphery, and the center 1105 of the surface 1103 is the center of the fuel pipe 101. The central axis 1106 and the backup ring 104 receiving portion plane 1107 of the fixing ring 1104 are arranged at the intersection.

  The fuel injection valve is pressed downward by the fuel pressure, and the force presses the holding plate 1101 downward through the fixing clip. At this time, if the fuel pipe 101 and the mounting hole on the engine head side are eccentric, the holding plate 1101 can be swung and inclined without being deformed along the surface 1103. As a result, the fuel pipe 101 and Even when the mounting hole on the engine head side is eccentric, it is possible to exert the effect of absorbing the bending moment by tilting the fuel injection valve itself, as in the case of the minute protrusion shown in the first embodiment. .

  Further, since the surface 1103 has a spherical shape, the center position does not move even after the fuel injection valve is inclined. For this reason, the outermost diameter portion of the surface 1107 does not contact the inner peripheral surface of the core 110 of the fuel injection valve, as indicated by a circular locus 1108 centered on the center 1105.

  Similarly, the surface 1102 on which the pressing plate 1101 contacts the fixing ring 1104 has a spherical shape that curves downward toward the fuel injection valve toward the outer periphery, and the surface 1102 has the same diameter as the surface 1103. The center is arranged so as to coincide with the center 1105 of the surface 1103. By arranging in this way, the holding plate 1101 is supported by the surface 1103 of the fixing ring 1104. By receiving the load received from the fuel injection valve by the fuel pressure on the surface, the stress applied to the surface 1102 and the surface 1103 can be reduced compared to the case of point contact or line contact.

By adopting such a structure, the diameter of the surface 1107 can be increased without restricting the inclination accuracy of the fuel injection valve.
The outer peripheral surface 1109 of the fixing ring 1104 has a tapered shape with a wider outer diameter as it approaches the front end side of the fuel injection valve. This taper shape is a clearance because the surface 1109 does not contact the inner peripheral surface of the core 110 of the fuel injection valve even when the fuel injection valve is inclined.

By having such a shape, the angle at which the fuel injection valve can be tilted can be secured without the O-ring 103 dropping off due to the fuel pressure.
Note that surface treatment may be performed on one or both of the surface 1102 and the surface 1103. Even if the load applied to the fuel injection valve increases due to the increase in fuel pressure, the strength of the surfaces 1102 and 1103 can be improved. Further, the lubricity is improved by the surface treatment, and the fuel injection valve is inclined more smoothly even when the fuel pressure is applied to the surfaces 1102 and 1103. That is, the frictional force between the surfaces 1102 and 1103 is reduced by the surface treatment, and wear due to friction is prevented. Examples of the surface treatment include Cr plating, Ni plating, and nitriding.

  Also, as shown in FIG. 12, the surface 1102b where the pressing plate 1101b contacts the fixing ring 1104 may have a tapered shape with a wider outer diameter as it approaches the tip of the fuel injection valve. At this time, it arrange | positions so that a part of normal line 1203 from on the surface 1102b may correspond with the center 1105. FIG. Geometrically, the normal from the contact portion between the spherical surface 1103 and the tapered surface 1102 b passes through the center 1105 of the spherical surface 1103. Therefore, the surface 1103 of the fixing ring 1104 is supported within the surface of the pressing plate 1101b instead of the corner of the tapered surface 1102b.

However, in this case, the contact portion between the surface 1202 and the surface 1103 is circular, and the contact portion area is reduced. Therefore, members such as stainless steel having sufficiently high strength are used for the fixing ring 1104 and the pressing plate 1201.
In any case of this embodiment, the spherical surface or the tapered surface provided on the pressing plate is not necessarily provided continuously in the circumferential direction. For example, FIG. 15 shows an example in which the pressing plate 1101 is viewed from the side of the fixing ring 1104, and the spherical surface 1102 is provided discontinuously in the circumferential direction.

FIG. 13 is a sectional view showing a fifth embodiment according to the present invention, and is an enlarged view of the vicinity of the fuel pipe 101 and the fuel injection valve mounting portion. In this embodiment, the surface 1303 with which the fixing ring 1304 abuts against the pressing plate 1301 has a spherical shape that curves downward toward the fuel injection valve toward the outer periphery, and the center 1305 of the surface 1303 is the center of the fuel pipe 101. The central axis 1306 is arranged at the intersection of the O-ring 103 and the central plane 1307 in the vertical direction. At this time, the surface 1307 is desirably the center in the vertical direction of the O-ring 103 when the fuel pipe 101 is inserted into the core 101 of the fuel injection valve and the O-ring 103 is compressed and deformed by applying fuel pressure. .

  Similarly, the surface 1302 where the pressing plate 1301 contacts the fixing ring 1304 has a spherical shape that curves downward toward the fuel injection valve toward the outer periphery, and the surface 1302 has the same diameter as the surface 1303. The center is arranged so as to coincide with the center 1305 of the surface 1303.

  By adopting such a structure, even when the fuel pipe 101 and the mounting hole on the engine head side are eccentric, the fuel injection valve itself is tilted in the same manner as the minute projection shown in the first embodiment. The effect of absorbing the bending moment can be exhibited.

  Further, since the surface 1303 has a spherical shape, the center position does not move even after the fuel injection valve is inclined. For this reason, the deviation of the compression allowance of the O-ring 103 can be reduced, and the reliability of the fuel seal can be improved.

  Furthermore, as shown in FIG. 14, the sealing surface between the O-ring 103 and the core 110 of the fuel injection valve may be spherical. In this embodiment, the seal surface 1408 between the O-ring 103 and the core 110 has a spherical shape, and the center of the surface 1408 is arranged to coincide with the center 1305. Similarly, the surface 1410 that contacts the surface 1408 of the backup ring 1409 has a spherical shape that curves downward toward the fuel injection valve toward the outer periphery, and the surface 1410 has the same diameter as the surface 1408, The center is arranged so as to coincide with the center 1305.

  By adopting such a structure, the center position of the surface 1408 does not move even after the fuel injection valve is inclined. For this reason, the compression allowance of the O-ring 103 becomes uniform all around, and the reliability of the fuel seal can be improved.

  Further, on the inner surface of the fuel pipe 101 insertion port of the core 101 of the fuel injection valve, the surface 1411 closer to the fuel pipe 101 than the seal surface 1408 has a tapered shape with a narrower outer diameter as it approaches the tip side of the fuel injection valve. This tapered shape makes it easy to insert the O-ring 103 or the backup ring 1409 having a larger outer diameter than the boundary portion 1412 between the surface 1408 and the surface 1411 or the fuel pipe 101 assembled with them into the core 110 of the fuel injection valve. In addition, even when the fuel injection valve is tilted, the fuel pipe 101 is escaped so as not to contact the inner peripheral surface of the core 110 of the fuel injection valve. 14 shows a structure in which the O-ring 103 and the backup ring 1409 are included in the core 110 before the fuel pipe 101 is inserted into the core 110 of the fuel injection valve. In the case of such a structure, since the boundary portion 1412 also has a function of preventing the O-ring 103 and the backup ring 1409 from dropping from the core 110, a protrusion or member for preventing the O-ring 103 and the backup ring 1409 from dropping off. Need not be provided separately.

  By having such a shape, even when the fuel pipe 101 and the mounting hole on the engine head side are eccentric, the angle at which the fuel injection valve can be tilted is ensured without the compression allowance of the O-ring 103 being biased. it can.

FIG. 18 is an enlarged cross-sectional view of a connection portion between the fuel injection valve and the fuel pipe 101 of the fuel injection device according to the sixth embodiment of the present invention.

  In a structure in which the fuel pipe 101 and the fuel injection valve are not fastened at the joint portion, for example, a structure in which the fuel injection valve is sandwiched and fixed between the fuel pipe and the engine head, by adopting such a structure, the fuel pressure is increased. The force with which the fuel injection valve is pressed against the engine head and the force with which the fuel pipe is pressed against the side opposite to the engine head can be alleviated.

101 ... Fuel pipe 102 ... Fixing clip 103 ... O-ring 104 ... Backup ring 105 ... Fixing ring 106 ... Holding plate 107 ... Spring 108 ... Coil 109 ... Housing 110 ... Core 111 ... Anchor 112 ... Upstream rod guide 113 ... Valve body 114 ... Nozzle holder 115 ... Valve body guide 116 ... Orifice plate 117 ... Filter 118 ... Plastic mold 119 ... Combustion gas seal member 120 ... Adjuster pin 121 ... Arrow 122 ... Retaining protrusion 123 ... Fixing protrusion 201 ... Connector 401 ... Micro protrusion 501 ..Arrow 502 ... Arrow 503 ... Arrow 601 ... Plate member 801 ... Plate member 802 ... angle R
803 ... Corner R
804... Fixing ring 901... Plate member 902... Micro projection 903... Fixing ring 1101 .. Plate member 1102 .. Surface 1103 .. Surface 1104 .. Fixing ring 1105. Shaft 1107 ・ ・ Plane 1108 ・ ・ Track 1601 ・ ・ Retaining protrusion 1701 ・ ・ Retaining member

Claims (7)

An internal combustion engine fuel injection apparatus having a fuel injection valve for injecting and supplying fuel to the internal combustion engine, wherein the fuel injection valve and a fuel pipe are sealed using an elastic member. A fuel injection device for an internal combustion engine, comprising an insertion hole for enclosing a connecting portion of the fuel pipe, wherein the elastic member is internally provided on the fuel injection valve or externally provided on the fuel pipe. 2. The fuel injection device according to claim 1, wherein the fuel injection valve is detachably fixed to the fuel pipe by a plate-shaped fastening member. 3. The fuel injection device according to claim 1, wherein the fuel injection valve is detachably fixed to the fuel pipe by a clip-shaped fastening member. 4. The fuel injection device according to claim 2, wherein a contact portion where the fastening member contacts the fuel pipe is provided separately from a seal portion for sealing the fuel, and the contact portion is formed from the fastening member. A fuel injection device, wherein the contact portion is plastically deformed when a bending moment is generated with respect to the axis of the fuel injection valve. 5. The fuel injection device according to claim 4, wherein the contact portion is made of a material having a lower tensile strength or a lower hardness than the fastening member. 6. The fuel injection device according to claim 4, wherein the contact portion is formed by a protrusion that contacts the fastening member. 6. The fuel injection device according to claim 4, wherein the fastening member and a horseshoe shape made of a material having a lower yield point than any of the fastening member and a fixing portion of the fuel pipe that fixes the fuel injection valve by the fastening member. A fuel injection device, wherein a member is provided between the fastening member and the fixed portion, and the abutment portion is constituted by the horseshoe-shaped member.