Fuel injection device for internal combustion engine

Abstract

This fuel injection device (1) includes: a fuel injection valve (2); a fuel supply member (3) comprising a holding part (11) for holding one end section (4) of the fuel injection valve (2); an O-ring (6) for sealing a connection part between the holding part (11) and the fuel injection valve (2); and a rotation prevention mechanism (14) for guiding the insertion of the fuel injection valve (2) into the holding part (11) and preventing rotation of the fuel injection valve (2). The rotation prevention mechanism (14) has: a claw part (9) provided to the fuel injection valve (2); and a rotation restriction part (13) provided on the outer peripheral surface (12) of the holding part (11) and capable of accommodating the claw part (9). The claw part (9) is long enough that the leading end position thereof is located closer to the fuel supply member (3) side than a portion that protrudes furthest outward in the radial direction of the O-ring.

Description

Fuel injection system for internal combustion engines

[0001] The present invention relates to a fuel injection device for an internal combustion engine.

[0002] For example, Patent Document 1 discloses a technique in which a plurality of fuel injection valves are mounted in advance on a single rail member for fuel distribution and then assembled to an engine all at once.

[0003] In Patent Document 1, the fuel injection valve needs to be rotated while being adjusted in order to assemble it in the correct position relative to the rail member, which can twist the O-ring attached to the connection port of the rail member that connects to the fuel injection valve, potentially adversely affecting the O-ring.

[0004] In other words, when connecting a fuel injection valve and a rail member for distributing fuel that is connected to the fuel injection valve, further improvements are expected to be made to prevent adverse effects on the O-ring that seals this connection.

[0005] Japanese Patent Application Laid-Open No. 2003-239828

[0006] A fuel injection device for an internal combustion engine according to the present invention includes a fuel injection valve, a fuel supply member having a holder into which one end of the fuel injection valve is inserted and held, a seal member attached to the outer periphery of the one end of the fuel injection valve and sealing a connection between the holder and the fuel injection valve, and a rotation prevention mechanism that guides the insertion of the fuel injection valve into the holder and prevents rotation of the fuel injection valve. The rotation prevention mechanism includes a claw portion provided on the fuel injection valve and extending elongately along the insertion direction of the fuel injection valve into the holder, and a groove-shaped rotation restricting portion provided at a predetermined position on the outer periphery of the holder and capable of receiving a tip end of the claw portion. The claw portion is formed so that its tip end along the insertion direction is located toward the fuel supply member in the insertion direction beyond the radially outermost portion of the seal member.

[0007] In the fuel injection device for an internal combustion engine of the present invention, circumferential positioning of the fuel injection valve with respect to the fuel supply member is completed by attaching the fuel injection valve to the holding portion so that the claw portion enters the rotation restricting portion. Therefore, in the fuel injection device of the present invention, it is not necessary to rotate the fuel injection valve in the circumferential direction to perform circumferential positioning in a state in which the seal member is most deformed in the compression direction, and it is possible to prevent the seal member from being twisted by the rotation of the fuel injection valve and suffering adverse effects.

[0008] The fuel injection valve of the present invention is provided with a fuel injection valve that is provided with an O-ring and is connected to the fuel injection valve through a connection hole of the fuel injection valve.

[0009] An embodiment of the present invention will be described in detail below with reference to the drawings.

[0010] Fig. 1 is an explanatory diagram showing an outline of a fuel injection device 1 for an internal combustion engine according to the present invention. Fig. 2 is a cross-sectional view of a main part of the fuel injection device 1 for an internal combustion engine according to the present invention. Fig. 3 is a perspective view showing a main part of a fuel injection valve 2 in the fuel injection device 1 for an internal combustion engine according to the present invention. Fig. 4 is an explanatory diagram showing a schematic cross section of an O-ring 6 attached to the fuel injection valve 2.

[0011] As shown in Fig. 1, the fuel injection device 1 has a fuel injection valve 2 and a fuel supply member 3 for supplying fuel to the fuel injection valve 2. One end (base end) 4 of the fuel injection valve 2, which is one end side in the longitudinal direction (the upper side in the vertical direction in Fig. 1), is inserted into and held in a holding portion 11 of the fuel supply member 3. The other end (tip end) 5 of the fuel injection valve 2, which is the other end side in the longitudinal direction (the lower side in the vertical direction in Fig. 1), is connected to, for example, a cylinder head of an internal combustion engine (not shown).

[0012] The fuel injection valve 2 is provided for each cylinder of an internal combustion engine (not shown), for example. The fuel injection valve 2 has an elongated rod shape or a stepped cylindrical shape overall, and injects fuel supplied from one end 4 from the other end 5, which is the other end in the longitudinal direction (the lower end in the up-down direction in FIG. 1 ).

[0013] An O-ring 6 made of, for example, a rubber material is attached as a sealing member to the outer periphery of one end 4 of the fuel injection valve 2. The O-ring 6 has an annular shape and provides a seal between the holding portion 11 and the connecting portion of the fuel injection valve 2.

[0014] Furthermore, an exterior member 7 that constitutes part of a rotation prevention mechanism 14 (described later) is attached to one end 4 of the fuel injection valve 2 at a predetermined position closer to the other end 5 than the O-ring 6. The exterior member 7 has a base 8 that is bifurcated so as to be able to hold the fuel injection valve 2 in place from the radial direction, and claw portions 9 that are perpendicular to the base 8. The exterior member 7 has a generally L-shape as a whole, and the base 8 is fixed to the fuel injection valve 2. In other words, the claw portions 9 can be considered to be provided on the fuel injection valve 2.

[0015] When the exterior member 7 is attached to the fuel injection valve 2, the claw portion 9 is spaced a predetermined distance in the radial direction of the fuel injection valve 2 from a central axis C1 of the fuel injection valve 2 that extends along the longitudinal direction of the fuel injection valve 2. The claw portion 9 has an elongated rectangular plate shape that extends along the insertion direction of the fuel injection valve 2 into the holding portion 11. In other words, the claw portion 9 has an elongated rectangular plate shape that extends along the central axis C1 of the fuel injection valve 2 that extends along the longitudinal direction of the fuel injection valve 2.

[0016] The fuel supply member 3 is capable of supplying (distributing) fuel to, for example, a plurality of fuel injection valves 2, and has a rail portion 10 extending along the cylinder row direction of the internal combustion engine, and a cylindrical holder portion 11 with a bottom that protrudes from the outer circumferential surface of the rail portion 10. The fuel supply member 3 has the holder portions 11 in a number corresponding to the number of cylinders of the internal combustion engine.

[0017] The holding portion 11 is configured to insert and hold one end 4 of the fuel injection valve 2 on its inner circumferential side. The holding portion 11 has a groove-shaped rotation restricting portion 13 formed at a predetermined position on the outer circumferential surface 12 thereof, the groove-shaped rotation restricting portion 13 extending along the insertion direction. In other words, the holding portion 11 has a groove-shaped rotation restricting portion 13 formed at a predetermined position on the outer circumferential surface 12 thereof, the groove-shaped rotation restricting portion 13 being parallel to the central axis C2 of the holding portion 11. The central axis C2 of the holding portion 11 coincides with the central axis C1 of the fuel injection valve 2 when held by the holding portion 11.

[0018] The rotation restricting portion 13 constitutes a rotation prevention mechanism 14 together with the claw portion 9 of the exterior member 7, and is capable of receiving the tip end of the claw portion 9 when the circumferential attachment position of the fuel injection valve 2 relative to the fuel supply member 3 is at a desired attachment position. In other words, by forming the rotation restricting portion 13 at a predetermined position of the holding portion 11, the fuel injection valve 2 is held at a desired circumferential attachment position relative to the fuel supply member 3. The rotation restricting portion 13 is a groove with a generally U-shaped cross section that continues linearly from the open end of the holding portion 11 toward the rail portion 10 side.

[0019] The anti-rotation mechanism 14 has a claw portion 9 provided on the fuel injection valve 2 side and a rotation restricting portion 13 provided on the fuel supply member 3 side, and guides the insertion of the fuel injection valve 2 into the holding portion 11 and restricts the circumferential rotation of the fuel injection valve 2. In other words, the anti-rotation mechanism 14 is capable of preventing the rotation of the fuel injection valve 2 by restricting the circumferential rotation of the fuel injection valve 2 by accommodating the claw portion 9 within the rotation restricting portion 13.

[0020] The claws 9 are formed to be located radially outward of the bottom surface of the rotation restricting portion 13 so that their tip ends can be accommodated in the rotation restricting portion 13 formed on the outer circumferential surface 12 of the holder 11. Furthermore, the claws 9 are spaced a predetermined distance radially of the fuel injection valve 2 from the central axis C1 so that the claws 9 overlap with the space within the rotation restricting portion 13 in the radial direction of the holder 11.

[0021] As shown in Figures 2 to 4, the fuel injection device 1 is formed so that, when the exterior member 7 is attached to the fuel injection valve 2, the tip position of the claw portion 9 along the insertion direction is at a length that is located closer to the fuel supply member 3 in the insertion direction than the radially outwardmost portion of the O-ring 6 attached to the fuel injection valve 2.

[0022] In other words, the claw portion 9 is formed to have a length such that, when the outer casing 7 is attached to the fuel injection valve 2, the tip position along the central axis C1 of the fuel injection valve 2 is located closer to one end of the fuel injection valve 2 than the radially outwardmost part of the O-ring 6 attached to the fuel injection valve 2.

[0023] 3 and 4 is an auxiliary line indicating the radially outermost portion of the O-ring 6 attached to the fuel injection valve 2.

[0024] In the fuel injection device 1 of the above-described embodiment, when the fuel injection valve 2 is attached to the holding portion 11 of the fuel supply member 3, the tip of the claw portion 9 reaches the rotation restriction portion 13 of the holding portion 11 before the radially outwardmost portion of the O-ring 6 comes into contact with the holding portion 11.

[0025] In addition, when the fuel injection valve 2 is attached to the holding portion 11, the anti-rotation mechanism 14 restricts the movement of the claw portion 9 along the circumferential direction of the fuel injection valve 2 by positioning (accommodating) the claw portion 9 within the rotation restriction portion 13, thereby preventing the fuel injection valve 2 from rotating.

[0026] In other words, in the fuel injection device 1, the circumferential positioning of the fuel injection valve 2 relative to the fuel supply member 3 is completed by attaching the fuel injection valve 2 to the holding portion 11 of the fuel supply member 3 so that the claw portion 9 enters the rotation restriction portion 13.

[0027] Therefore, the fuel injection device 1 does not need to rotate the fuel injection valve 2 circumferentially to position it circumferentially when the O-ring 6 is most deformed in the compression direction, and it is possible to prevent the O-ring 6 from being twisted by the rotation of the fuel injection valve 2 and suffering adverse effects.

[0028] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention.

[0029] For example, the fuel injection device 1 may be set such that, when the fuel injection valve 2 is attached (inserted) into the holder 11, the tip positions of the claw portions 9 along the insertion direction (along the central axis C1 of the fuel injection valve 2) are located closer to one end of the fuel injection valve 2 than the portion of the O-ring 6 attached to the fuel injection valve 2 that first comes into contact with the holder 11. In other words, the length of the claw portions 9 along the insertion direction may be set such that the O-ring 6 comes into contact with the holder 11 after the claw portions 9 and the rotation restricting portion 13 overlap with each other in the insertion direction.

[0030] When the length of the claw portion 9 along the insertion direction is set in this manner, the circumferential positioning of the fuel injection valve 2 relative to the fuel supply member 3 is completed when the O-ring contacts the holding portion 11, so it is possible to reliably prevent the O-ring from being twisted between the holding portion 11 due to the rotation of the fuel injection valve 2.

[0031] The dashed dotted line L2 in FIGS. 3 and 4 is an auxiliary line indicating the portion where the O-ring 6 attached to the fuel injection valve 2 first comes into contact with the holding portion 11.

[0032] For example, the claw portion 9 may be formed integrally with the fuel injection valve 2 .

Claims

1. A fuel injection valve that injects fuel supplied from one end from the other end, A fuel supply member for supplying fuel, which includes a holding portion into which one end of the fuel injection valve is inserted and held, An annular sealing member is attached to the outer circumference of one end of the fuel injector and seals the connection between the holding portion and the fuel injector. It has a rotation-preventing mechanism that guides the insertion of the fuel injection valve into the holding portion and prevents the fuel injection valve from rotating, The above-mentioned anti-rotation mechanism includes a claw portion provided on the fuel injector and extending elongated along the direction in which the fuel injector is inserted into the holding portion, and a groove-shaped rotation restricting portion provided at a predetermined position on the outer circumferential surface of the holding portion and capable of accommodating the tip of the claw portion. The claw portion is formed such that its tip position along the insertion direction is located on the fuel supply member side in the insertion direction, longer than the portion of the sealing member that protrudes most outward in the radial direction, and is set such that its tip position along the insertion direction is located on the fuel supply member side in the insertion direction, longer than the portion of the sealing member that first contacts the holding portion when the fuel injector is attached to the holding portion.

2. (delete)

3. The fuel injection device for an internal combustion engine according to claim 1, wherein the length of the claw portion along the insertion direction is set such that, in the insertion direction described above, the claw portion and the rotation restricting portion overlap before the sealing member contacts the holding portion.