JP3353851B2 - Fuel joint and fuel injection device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel coupling and a fuel injection device using the fuel coupling between a fuel injection valve of an internal combustion engine and a high-pressure fuel supply for supplying high-pressure fuel to the fuel injection valve. Things.

[0002]

2. Description of the Related Art Conventionally, as a fuel joint of a fuel injection device for supplying high-pressure fuel in an accumulator to a plurality of fuel injection valves provided for a plurality of cylinders of a multi-cylinder internal combustion engine, for example, as shown in FIG. Things are known. This fuel joint 20
Numeral 0 is attached to the pressure accumulating vessel 150 and supplies high-pressure fuel to the fuel injection valve via an injection steel pipe (not shown). When assembling the fuel joint 200 to the pressure accumulator 150, the male screw part 201 a formed on the body 201 of the fuel joint 200 and the female screw part 151 a formed on the inner wall forming the through hole 151 of the pressure accumulator 150 are screw-connected. The screw is tightened until the tapered outer wall 202a of the protruding portion 202 comes into contact with the seat portion 151b.
00 and a fuel passage in the fuel cell.

[0003] In the fuel joint disclosed in Japanese Patent Application Laid-Open No. 4-66769, an annular holder fitted to a pressure accumulating pipe and an outer portion are screw-coupled, and inserted into the outer portion by this screw connection. The fuel steel pipe is pressed against the tapered surface of the pressure accumulation pipe, and the injection steel pipe and the pressure accumulation pipe are connected.

[0004]

However, in the conventional fuel coupling shown in FIG. 8, when the fuel coupling 200 is detached from the accumulator 150, the external thread 201a and the internal thread 1
Metal chips such as screw burrs and burrs are generated from the holes 51a, and the metal chips may enter the pressure accumulator 150. When the metal scrap is supplied to the fuel injection valve together with the high-pressure fuel, the metal scrap enters the sliding portion of the fuel injection valve, which is a precision sliding member, and causes poor fuel injection such as non-injection, uneven injection, or continuous injection of fuel. There is a problem that causes.

In the fuel joint disclosed in Japanese Patent Application Laid-Open No. 4-66769, there is no means for pressing the injection steel pipe against the pressure accumulation pipe before the holder and the outer part are screwed together. In some cases, metal chips generated when the parts are screwed together enter the pressure accumulating pipe, and the metal chips are sent into the fuel passage of the fuel injection valve. The present invention has been made in order to solve such problems, and by preventing metal chips generated when a fuel joint is detached from a high-pressure fuel supply source from entering the high-pressure fuel supply source, An object of the present invention is to provide a fuel joint that enables good fuel injection and a fuel injection device using the same.

[0006]

According to a first aspect of the present invention, there is provided a fuel coupling comprising a high-pressure fuel supply source.
Female thread formed at the fuel inlet or fuel outlet of
An external thread portion for screw connection is provided on the outer peripheral wall, and the
A cylindrical housing having a fuel passage communicating with the fuel outlet in the axial direction; and the fuel inlet or the fuel outlet.
And a fuel passage communicating the fuel passage with the fuel passage. The fuel passage is provided so as to protrude from one end of the housing so as to be movable in an axial direction of the housing .
The female screw part and the male screw part of the housing are screwed.
Before starting the connection, the fuel inlet or the fuel outlet
A seal member abutting on a seat portion, a first urging unit for urging the seal member toward the one end of the housing, and the seal member energized by the first urging unit. And a locking member for locking to the housing.

According to a second aspect of the present invention, there is provided a fuel joint formed on an inner wall of the housing and through which fuel can flow, and a first seat portion housed in the housing and capable of abutting the first seat portion. A first valve member; and a second urging means for urging the first valve member in a direction of detaching the first valve member from the first seat portion. The first valve member abuts on the portion to close the fuel passage of the housing.

According to a third aspect of the present invention, there is provided a fuel joint formed on an inner wall of the housing and through which fuel can flow, and a second seat portion housed in the housing and capable of abutting the second seat portion. A second valve member, wherein when the fuel flows backward, the second valve member contacts the second seat portion to close the fuel passage of the housing.

According to a fourth aspect of the present invention, a fuel injection device is provided.
In a fuel injection device including a fuel injection valve of an internal combustion engine and a high-pressure fuel supply source that supplies high-pressure fuel to the fuel injection valve, the fuel injection device is provided between the high-pressure fuel supply source and the fuel injection valve, 3. A screw connection with a fuel supply.
Or a fuel coupling described in 3 above.

[0010]

According to the fuel joint of the present invention and the fuel injection device using the same, a seal member is housed so as to protrude a part from the housing of the fuel joint, and the seal member is biased by high-pressure fuel. When assembling a fuel coupling to a high pressure fuel supply by energizing the supply,
Before the housing and the high-pressure fuel supply are screwed together, the seal member and the high-pressure fuel supply are abutted and sealed, and when the fuel coupling is removed from the high-pressure fuel supply, the housing is screwed with the high-pressure fuel supply. After release, the seal member separates from the seal with the high pressure fuel supply. This prevents the metal debris, such as screw burrs and burrs, generated when attaching and detaching the fuel joint from the high-pressure fuel supply source from entering the high-pressure fuel supply source. It is possible to prevent the occurrence of injection failure such as no injection or continuous injection by entering the fuel injection section, and maintain good fuel injection of the fuel injection valve.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an embodiment in which the fuel injection device according to the first embodiment of the present invention is applied to a fuel injection system for a diesel engine (hereinafter, “diesel engine” is referred to as “engine”).

A piston 12, a connecting rod 13, and a crankshaft 14 are housed in a cylinder block 11 of the engine 10, and directed toward a combustion chamber 18 defined by an upper surface of the piston 12, an inner wall 15 of the cylinder, and a lower surface 16 of a cylinder head. Thus, a nozzle portion 19a of the fuel injection valve 19 is provided. The fuel injection of the fuel injection valves 19 provided independently for each of the plurality of cylinders is controlled by opening and closing an injection control solenoid valve 20, and each fuel injection valve 19 is controlled via an injection steel pipe 101 and a flow limiter 40. An accumulator 21 common to the cylinders is connected. During the period in which the injection control solenoid valve 20 is open, the high-pressure fuel stored in the pressure storage container 21 is supplied from the fuel injection valve 19 to the engine 1.
0 is injected into the corresponding cylinder. Since it is necessary to continuously accumulate a high predetermined pressure corresponding to the fuel injection pressure in the accumulator 21, the high-pressure supply pump 22
Is connected. The high-pressure supply pump 22 pressurizes the fuel sucked from the fuel tank 23 through the filter 24 to a high pressure, and controls and maintains the fuel in the accumulator 21 at a high pressure.

The electronic control unit ECU 30 for controlling this system receives information on the number of revolutions from, for example, a crank angle discriminating sensor 31 and a cylinder discriminating sensor 32, and determines the information in accordance with the engine operating state determined from these signals. The ECU 30 outputs a control signal to each of the injection control solenoid valves 20 so that the optimum injection timing and injection amount (injection period) are obtained. At the same time, the ECU 30 outputs a control signal to the high-pressure supply pump 22 so that the injection pressure becomes an optimum value according to the rotation speed, the engine load, and the like. The pressure accumulator 21 is provided with a pressure sensor 33 for detecting the pressure of the accumulator, and the discharge amount of the high-pressure supply pump 22 is adjusted so that the signal of the pressure sensor 33 becomes an optimum value set in advance according to the rotation speed and the load. Control.

The high-pressure fuel supplied from the high-pressure pump 22 to the accumulator 21 is supplied to the fuel injection valve 19 via the injection steel pipe 101, and is burned from the nozzle portion 19a in response to opening and closing of the injection control solenoid valve 20. It is injected into the chamber 18. Next, the detailed configuration of the flow limiter 40 will be described with reference to FIGS.
It will be described based on.

As shown in FIG. 3, the flow limiter 40 is attached to the through hole 59 of the accumulator 21 vertically downward from above. The through hole 59 communicates with a pressure storage chamber (not shown). As shown in FIG. 1, the flow limiter 40
A fuel passage 42 passing through the housing 41 in the axial direction is formed by the inner wall of the housing 41.
Accommodates a sealing member 51, a compression coil spring 52, a shim 53, a stopper 54, a piston 55, a ball 56, a slider 57 and a compression coil spring 58, and the end of the housing 41 on the side of the sealing member 51 is caulked. I have. The female screw portion 59a formed on the inner wall of the through hole 59 of the pressure accumulator 21 accommodating the flow limiter 40 and the male screw portion 41a formed on the outer wall of the housing 41 are screw-coupled to each other.
1 is assembled.

In the axial direction of the sealing member 51, the pressure accumulating vessel 21
A fuel passage 51a is formed to connect the pressure accumulation chamber (not shown) to the fuel passage 42, and an annular flange portion 51b is formed around the outer wall of the seal member 51. The tapered outer wall 51c on the fuel downstream side of the seal member 51 is
a and the female thread portion 59a are screwed into the housing 41.
The tapered outer wall 51d on the fuel upstream side is pressed against the seat portion 59b of the through hole 59.

The stopper 54 is a compression coil spring 52
As a result, a fuel passage 54a is formed in the axial direction, which is urged by the locking portion 41c formed on the inner wall of the housing 41 via the shim 53 and communicates the fuel upstream side and the fuel downstream side of the stopper 54. By changing the thickness of the shim 53,
The urging force of the compression coil spring 52 for urging the stopper 54 can be adjusted.

The piston 55 is formed in a cylindrical shape having a bottom on the fuel downstream side, and a fuel passage 55a communicating the fuel upstream side and the fuel downstream side is formed on the bottom. Piston 5
5 is slidably supported on the inner wall of the housing 40 forming the fuel passage 42, and the movement of the piston 55 toward the fuel upstream side is regulated by the stopper 54. The ball 56
It is in contact with the upper end surface of the piston 55 and is fitted in a concave portion 57a of a slider 57 described later.

The slider 57 includes a compression coil spring 5
8, a flat notch 57b is formed so as to be urged toward the fuel upstream side and have a predetermined clearance between the outer wall of the slider and the inner wall of the housing. In the state shown in FIG. 1 in which the flow limiter 40 is assembled to the accumulator 21, the urging force of the compression coil spring 52 is larger than the urging force of the compression coil spring 58, and the stopper 54
c.

The high-pressure fuel accumulated in the accumulator of the accumulator 21 passes from the accumulator of the accumulator 21 through the fuel passage 51a, the fuel passage 54a, the fuel passage 55a, the notch 57b, the injection steel pipe 101, and the fuel injection valve. 19 is supplied. When the fuel supply pressure from the pressure storage container 21 becomes excessive, the ball 56 overcomes the urging force of the compression coil spring 58 and abuts on the seat portion 41d formed on the inner wall of the housing 41 to close the fuel passage 42.

FIGS. 4 and 5 show the procedure for assembling the flow limiter 40. FIG. A compression coil spring 58, a slider 57, a ball 56, a piston 55,
Stopper 54, shim 53, compression coil spring 52,
By inserting the seal members 51 in order and caulking the end of the housing 41 on the seal member 51 side, the flange portion 51b of the seal member 51 is locked to the housing 41 as shown in FIG. Fall is prevented.
FIG. 5 before assembling the flow limiter 40 to the pressure accumulator 21
In the state shown in (1), the tapered outer wall 51c of the seal member 51 and the tapered inner wall 41b formed on the inner wall of the housing 41 have a certain clearance.

As shown in FIG. 1, when assembling the flow limiter 40 to the accumulator 21, the tapered outer wall 51 d of the seal member 51 protruding from one end of the housing 40.
Abuts on the sheet portion 59b of the through hole 59, and then the male screw portion 41a is screwed into the female screw portion 59a. With this screw tightening, the tapered inner wall 41b becomes the tapered outer wall 51.
When gradually approaching and abutting on c, the screw is further tightened to sufficiently press the tapered outer wall 51d against the seat portion 59b.

In the flow limiter 40 of the first embodiment, when assembling the flow limiter 40 to the accumulator 21, the tapered outer wall 51 d of the seal member 51 abuts the sheet portion 59 b of the through hole 59, and then the female screw of the through hole 59 Part 59a
And the male screw portion 41a of the housing 41 are screw-connected, so that metal debris such as screw burrs and burrs generated at the time of screw connection are blocked by the seal portion between the tapered outer wall 51d and the seat portion 59b. Collect outside the passage. Therefore, metal debris such as screw burrs and burrs are prevented from entering the accumulator 21, and the metal debris is removed from the fuel injection valve 19.
Can be prevented from entering the fuel passage. Further, in the first embodiment, the flow limiter 40 is assembled vertically downward from above the pressure accumulator 21. However, when the flow limiter 40 is assembled upward from below the pressure accumulator 21, the metal debris is also reduced. Can be prevented from invading.

In the first embodiment, before the flow limiter 40 is assembled to the pressure accumulating vessel 21, the end of the housing 41 is caulked to prevent the seal member 51 from falling. It is possible to prevent the sealing member 51 from falling. After the sealing member 51 is inserted into the housing 41, a pin is inserted into a through hole provided in a radial direction at the end of the housing 41 to lock the flange portion 51b. The length of the pin is
9 female screw part 59a and housing 41 male screw part 41a
The length is adjusted so that it does not interfere with the screw connection. Alternatively, pins may be inserted into a plurality of through holes provided at the end of the housing 41 to lock the flange portion 51b. A male screw portion is formed on the outer wall of the flange portion 51b, and a female screw portion is formed on the inner wall at the end of the housing 41. The seal member 51 is screwed in until it passes through the female screw portion, and the seal member 51 is locked by the mutual threads. I do.
The seal member 51 is pressed through the end of the housing 41. A protrusion is formed on the seal member 51, a notch through which the protrusion can pass is formed on the inner wall of the end of the housing 41, and after the protrusion of the seal member 51 passes through the notch on the housing 41, By rotating 51, a locking portion with which the protrusion of the sealing member 51 can be locked is formed on the inner wall of the end of the housing 41.

In the present invention, the seal member may be urged by an elastic body such as a leaf spring or rubber instead of the compression coil spring. FIG. 6 shows a second embodiment of the present invention. In the second embodiment, the seal outer wall 61a of the seal member 61 is formed in a convex spherical surface, and the sheet portion 70b of the through hole 70 is formed in the same tapered shape as in the first embodiment. Then, the male screw part 41a and the female screw part 70a are screw-connected to each other to form the seal outer wall 61a on the seat part 70b.
Pressed to.

In the second embodiment, as in the first embodiment, it is possible to prevent metal chips generated when the flow limiter 60 is mounted on the pressure accumulator 21 from entering the pressure accumulator 21. FIG. 7 shows a third embodiment of the present invention. In the third embodiment, the end face 81a of the seal member 81 is formed flat, and the end face 81a is formed.
An annular gasket 82 is inserted between the gasket and the sheet portion 90b of the through hole 90. The end face 81a is pressed against the gasket 82 by screw-connecting the male screw part 41a and the female screw part 90a, and the end face 81a and the seat part 90
b is sealed well.

In the third embodiment, when assembling the flow limiter 80 to the pressure accumulating vessel 21, the end face 81 of the sealing member 81
a between the gasket 8 and the sheet surface 90 b of the through hole 90.
By inserting 2, the gasket 82 absorbs the manufacturing variation of the seal member 81 and the through hole 90, so that it is not necessary to form the end face 81a and the seat portion 90b precisely, and the number of manufacturing steps can be reduced.

In the first to third embodiments described above, the flow limiter is used as the fuel joint between the pressure accumulator and the injection steel pipe. However, in the present invention, the following fuel joints are used instead of the flow limiter. It is possible to use. A non-return valve for preventing backflow of fuel from the fuel injection valve, a fuel joint having a function of a flow limiter and a non-return valve,
A fuel injection pipe having a fuel joint without a function of a flow limiter and a check valve, a seal member, and a biasing means for the seal member.

Further, the above-mentioned fuel joint is configured to be mounted on the fuel outlet side of the pressure accumulator, but it is possible to mount it on the fuel inlet side of the pressure accumulator or the fuel inlet side of the high pressure supply pump.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a fuel injection device according to a first embodiment of the present invention.

FIG. 2 is an embodiment in which the fuel injection device according to the first embodiment of the present invention is applied to a fuel injection system for a diesel engine.

FIG. 3 is an enlarged partial sectional view of the pressure accumulator according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing a procedure of assembling the flow limiter according to the first embodiment of the present invention.

FIG. 5 is a sectional view showing a state before the flow limiter according to the first embodiment of the present invention is assembled to the pressure accumulator.

FIG. 6 is a sectional view showing a main part of a fuel injection device according to a second embodiment of the present invention.

FIG. 7 is a sectional view showing a main part of a fuel injection device according to a third embodiment of the present invention.

FIG. 8 is a sectional view showing a main part of a conventional fuel injection device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 19 Fuel injection valve 21 Accumulator (high-pressure fuel supply source) 22 High-pressure supply pump (high-pressure fuel supply source) 40 Flow limiter (fuel joint) 41 Housing 41d Seat portion (first seat portion) 42 Fuel passage 51 Seal member 51c Fuel Passage 52 Compression coil spring (biasing means, first biasing means) 56 Ball (first valve member) 58 Compression coil spring (second biasing means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02M 55/02 330 F02M 55/02 350 F02M 59/44 F16L 5/02

Claims (4)

(57) [Claims] 1. A fuel inlet or fuel outlet for a high pressure fuel supply.
The male screw part which is screwed with the female screw part formed in the mouth
Has on the outer peripheral wall and communicates with the fuel inlet or the fuel outlet
A cylindrical housing having a fuel passage extending in the axial direction, a fuel passage communicating the fuel inlet or the fuel outlet with the fuel passage, and one end of the housing movably in the axial direction of the housing. And the female screw part of the high-pressure fuel supply
Before the male thread of the housing starts screwing,
A seal member that abuts the fuel inlet or the fuel outlet seat portion, a first urging unit that urges the seal member toward the one end of the housing, A locking member for locking the seal member urged by the urging means to the housing. 2. A first seat portion formed on an inner wall of the housing and through which fuel can flow, a first valve member housed in the housing and capable of abutting on the first seat portion, and the first valve member; A second urging means for urging the first valve member in a direction in which the first valve member is disengaged from the first seat portion, wherein the first valve member contacts the first seat portion when the fuel supply pressure is excessive. 2. The fuel joint according to claim 1, wherein the fuel passage contacts and closes the fuel passage of the housing. 3. A fuel supply system comprising: a second seat portion formed on an inner wall of the housing and through which fuel can flow, and a second valve member housed in the housing and capable of abutting on the second seat portion. 2. The fuel coupling according to claim 1, wherein when the fuel flows backward, the second valve member abuts on the second seat portion to close the fuel passage of the housing. 4. A fuel injection device comprising a fuel injection valve of an internal combustion engine and a high-pressure fuel supply source for supplying high-pressure fuel to the fuel injection valve, wherein a fuel injection valve is provided between the high-pressure fuel supply source and the fuel injection valve. 4. A fuel injection device comprising the fuel joint according to claim 1, which is provided and is screw-connected to the high-pressure fuel supply source.