JPH1172059A - Pressure accumulating type fuel infection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make quickly the judgement whether the fuel leaks outside at a pressure accumulating chamber. SOLUTION: A pipe 41 as a member to be fastened is fitted in a large diameter hole 33 provided in a pressure accumulating vessel 1, and a seat part 42 of this pipe 41 is contacted with a slope 333. To check the liquid-tightness of the vessel 1, leakage sensing of the fuel can be made ocularly through an externally leading communication hole 61 when a leakage is generated from a pressure accumulating chamber 2 through the gap between the slope 333 and the seat part 42. This permits quick leakage sensing of the fuel at the seal part between the slope 333 and seat part 42 before fuel leakage occurs at the end 13a of the hole 33, which enables enhancement of the inspection efficiency of the products.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for an internal combustion engine in which high-pressure fuel stored in a pressure storage chamber is injected from a plurality of injectors at a predetermined timing.

[0002]

2. Description of the Related Art As means for supplying high-pressure fuel to a plurality of injectors provided corresponding to a plurality of cylinders of a multi-cylinder internal combustion engine, a so-called common rail type fuel injection for supplying high-pressure fuel stored in a pressure storage chamber to each injector. Devices are known. Such a common rail has an inlet side connected to a high-pressure supply pump and an outlet side connected to a plurality of injectors via a plurality of pipes.

For example, as shown in FIG. 6 and FIG. 7, a pressure accumulator 1 as a common rail is formed with a pressure accumulator 2 penetrating in a longitudinal direction, and communicating passages 13, 14, in a direction orthogonal to the pressure accumulator 2. 15 and 16 are formed. One ends 13a, 14 of the communication passages 13, 14, 15, 16
a, 15a and 16a open on one outer wall of the pressure accumulator 1 and the other ends 13b, 14b, 15b and 16b open on the other outer wall of the pressure accumulator 1. And the communication paths 13, 1
Large diameter holes 23, 24, 25, 26 for pipe attachment are formed at each end of each of the pipes 4, 15, 16. For effective use of the large-diameter hole, for example, a large-diameter hole 2
Pipes for supplying high-pressure fuel from the high-pressure supply pumps are attached to 4, 25, and the other large-diameter holes 23, 26, 33, 3
At pipes 4, 35 and 36, pipes for supplying pressurized fuel to the injectors are attached. Further, one end 2 of the accumulator 2
A pressure sensor (not shown) for detecting the pressure of the pressure accumulating chamber 2 is attached to a, and a safety valve (not shown) for releasing the fuel to the outside when the pressure of the pressure accumulating chamber exceeds a predetermined value is attached to the other end 2b.

FIG. 7 is a sectional view of a part of a section taken along the line VII-VII shown in FIG. As shown in FIG. 7, a sheet portion 4 of a pipe 41 as a member to be fastened is provided on a slope 333 of the pressure accumulator 1.
The screw part 43 is fastened to the screw part 331 so that the screw part 2 comes into contact with the screw part 331. The outlet side of the pipe 41 is connected to the injector via a high-pressure pipe (not shown). The pressure accumulating chamber 2 is filled with fuel, and the relief portion 332 of the large-diameter hole is a space. The seat 42 of the pipe 41 and the slope 333 ensure liquid tightness of the fuel.

[0005]

However, according to such a conventional pressure-accumulation type fuel injection device, when checking that the liquid tightness between the seat portion 42 and the slope 333 is ensured at the time of product inspection, The liquid tightness of the fuel is determined based on whether the fuel leaks to the end 13a of the communication passage 13. When the fuel in the accumulator 2 leaks from the gap between the slope 333 and the seat portion 42 to the escape portion 332 side, the leaked fuel flows into the space in the escape portion 332, and the escape portion 332 is filled with fuel. Then, when a part of the filled fuel further passes through the screw portion 331 and reaches the end 13 a of the communication passage 13, the leakage of the fuel can be visually confirmed.

For this reason, when checking the liquid tightness of the pressure accumulator for inspection, it takes a long time to detect leakage of fuel from the seal portion, and there is a problem that the time required for the determination is long. When investigating the reason why this determination takes a long time, it is understood that one of the causes is that the escape portion and the screw portion are formed in the one-way communication passage 13 in the process of the leaked fuel flowing out. You.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pressure-accumulation type fuel injection device that can determine in a short time whether or not fuel has leaked from a pressure accumulation chamber of a pressure accumulation container.

[0008]

According to the pressure accumulating fuel injection device according to the first aspect of the present invention, the member to be fastened is fitted into the large-diameter hole of the pressure accumulator, and the seat portion of the member to be fastened is provided on the slope. Abut At the time of checking the liquid tightness of the accumulator, when fuel leaks from the accumulator through the gap between the slope and the seat portion, the fuel leak can be visually detected through the external communication hole. Therefore, it is possible to detect the leakage of the fuel from the seal portion between the slope and the seat portion in a short period of time, so that the inspection efficiency of the product is improved.

According to the pressure accumulating fuel injection device according to the second aspect of the present invention, since the external communication hole is formed linearly through the pressure accumulating vessel, the external communication hole can be easily formed by drilling. Can be. In addition, since the axis of the external communication hole is in a torsional positional relationship with the axis of the accumulator, the rigidity of the accumulator is not impaired. According to the pressure accumulating fuel injection device according to claim 3 of the present invention, since the screw portion of the member to be fastened is screwed to the screw portion formed on the inner wall of the large-diameter hole of the pressure accumulator,
The liquid-tight sealing operation is completed when the sheet portion of the member to be fastened comes into contact with the slope of the accumulator at the same time as the completion of the screw tightening operation. Therefore, there is an effect that the efficiency of assembling the product is improved.

According to the pressure accumulating fuel injection device of the fourth aspect of the present invention, since the pipes are connected to a plurality of injectors, the liquid-tightness inspection is performed for each of the plurality of connected members. There is an effect that can be easily performed.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 3 show one embodiment in which the present invention is applied to a fuel injection device for a diesel engine.

In FIG. 2, a diesel engine (hereinafter referred to as a diesel engine)
Injectors 5 are individually provided for the plurality of cylinders in the “engine” 4, and the injection of fuel from the injectors 5 into each cylinder is controlled by turning on and off an injection control solenoid valve 6. The injector 5 is connected to the accumulator 2 of the high-pressure accumulator 1 common to each cylinder. During the period in which the injection control solenoid valve 6 is open, the fuel in the accumulator 2 is supplied from the injector 5 to each cylinder of the engine 4. It is injected. Since it is necessary to continuously accumulate a high predetermined pressure corresponding to the fuel injection pressure in the accumulator 2, a high-pressure supply pump 9 is connected via a supply pipe 7 and a discharge valve 8. The high-pressure supply pump 9 pressurizes the fuel sucked from the fuel tank 10 via the known low-pressure supply pump 11 to a high pressure, and controls and maintains the fuel in the accumulator 2 at a high pressure.

The electronic control unit ECU 40 for controlling this system receives information on the number of revolutions and the load from, for example, the engine revolution number sensor 18 and the load sensor 19, and responds to the engine operating state determined from these signals. The ECU 40 outputs a control signal to each of the injection control solenoid valves 6 so that the determined optimum injection timing and injection amount (injection period) are obtained. At the same time, the ECU 40 outputs a control signal to the high-pressure supply pump 9 so that the injection pressure becomes an optimum value according to the rotation speed and the load. A pressure sensor 20 for detecting a common rail pressure is provided in the pressure accumulating chamber 2, and a discharge amount of the high-pressure supply pump 9 is adjusted so that a signal of the pressure sensor 20 becomes an optimum value set in advance according to a rotation speed and a load. Control.

As shown in FIGS. 1 and 3, the pressure accumulating vessel 1 has a pressure accumulating chamber 2 as a fuel pressure accumulating passage formed linearly inside thereof along the longitudinal direction. A communication passage 13 is formed in a direction orthogonal to the axis in which the pressure accumulating chamber 2 extends. The communication passage 13 has a large diameter hole 33 and a small diameter hole 5.
3, and the large-diameter hole 33 includes a screw portion 331 and a relief portion 332. Inner wall of relief section 332 and small diameter hole 53
Is connected to the inner wall by a conical slope 333.
Then, an external communication hole 61 is formed that penetrates through the accumulator 1 in a positional relationship orthogonal to the axis of the relief portion 332 and twisted with respect to the axis of the accumulator 2. The external communication hole 61 is provided for each pipe 4
It is provided corresponding to the large-diameter hole 33 for attachment.

A pipe 41 as a member to be fastened, which is a part of a pipe connecting the accumulator 1 and the injector 5, has an internal passage communicating the accumulator 2 with the fuel passage of the injector 5, and has a large-diameter hole. It is screwed and fixed to the screw part 331 of the 33. The sheet part 42 of the fastening part 41 is in contact with the slope 333, and the screw part 43 is screwed to the screw part 331.
In this screw connection, the seat portion 42 comes into contact with the slope 333,
At this contact surface, the fuel filling the pressure accumulating chamber 2 and the small-diameter hole 53 is sealed so as not to leak to the escape portion 332 side. In order to confirm that fuel does not leak from the seal portion, a liquid tightness inspection is performed in a product inspection process.

According to the configuration of this embodiment, when the fuel filled in the pressure accumulating chamber 2 leaks from the seal between the inclined surface 333 and the seat portion 42 to the escape portion 332 side, the leaked fuel passes through the external communication hole 61. Leakage outside the accumulator 1 can be visually checked. Therefore, when fuel leaks from the seal portion, the fuel leaks directly from the escape portion 332 to the outside of the pressure accumulator 1 via the external communication hole 61, so that the fuel leak can be inspected at an early stage.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
And FIG. In the second embodiment, when the accumulator type fuel injection system is actually used, foreign substances such as dust and dust are prevented from entering the external communication holes 61 from the outside.
A screw portion 62 is formed at the open end of the external communication hole 61. A blind plug 63 can be screw-connected to the screw portion 62. Blind plug 6
Numeral 3 comprises a screw portion 64 and a head 65, and an end surface 66 on the lower surface of the head 65 is tightly fastened to the flat surface 21 of the outer wall of the accumulator 1. FIG. 5 shows a state where the blind plug 65 is screwed to the screw portion of the pressure accumulator 1.

According to this embodiment, when inspecting the product, the blind plug 65 is removed, and it is determined whether or not the escape portion 332 has leaked fuel. Thereby, at the time of inspection, the pressure accumulation chamber 2 and the small-diameter hole 5
When the fuel filled in 3 leaks from the seal portion, the leak of the fuel can be detected at an early stage from the escape portion 332 through the external communication hole 61. At the time of inspection, when it is determined that there is no fuel leakage, the blind plug 65 is screwed to the screw portion 62. Then, as shown in FIG. 5, the blind plug 63 is screwed to the pressure accumulator 1. Therefore, foreign substances such as dust and dust do not enter from the opening end side of the external communication hole 61.

As another embodiment of the present invention, it is possible to form an external communication hole that opens in the thread portion of the large-diameter hole of the pressure accumulator. Further, the axis of the external communication hole may be penetrated in a direction perpendicular to the axis of the small diameter hole and parallel to the axis extending to the accumulator or inclined in a twisted positional relationship.

[Brief description of the drawings]

FIG. 1 is a schematic partial cross-sectional view showing a pressure accumulating fuel injection device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a pressure accumulating fuel injection system according to a first embodiment of the present invention.

FIG. 3 is a plan view showing an accumulator and its mounting parts of the accumulator type fuel injection device according to the first embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing a state before a blind plug is attached to a pressure accumulator according to a second embodiment of the present invention.

FIG. 5 is a partial cross-sectional view showing a state after a blind plug is attached to a pressure accumulator according to a second embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a pressure storage container of a conventional pressure storage type fuel injection device.

FIG. 7 is a partial cross-sectional view taken along line VII-VII shown in FIG. 6;

[Description of Signs] 1 Accumulator 2 Accumulator 4 Diesel engine (engine) 5 Injector 6 Injection control solenoid valve 7 Supply pipe 13 Communication passage 33 Large diameter hole 41 Pipe (member to be fastened) 42 Sheet part 43 Screw part 61 External Communication hole 62 Screw part 63 Blind plug 331 Screw part 332 Escape part 333 Slope

Claims (4)

[Claims] 1. A pressure accumulating fuel injection device having a pressure accumulating chamber for accumulating a pressure of fuel supplied to an injector provided for each cylinder of an internal combustion engine, comprising: a pressure accumulating chamber extending in a longitudinal direction, and a small diameter communicating with the pressure accumulating chamber. An accumulator having a hole, a large-diameter hole communicating with the outer wall, an annular slope connecting the inner wall of the small-diameter hole and the inner wall of the large-diameter hole, and an external communication hole communicating the outside of the large-diameter hole with the outside; A pressure accumulating type fuel injection device comprising: a seat portion capable of contacting the large diameter hole; and an internal passage communicating with the small diameter hole, and a member to be fastened to the large diameter hole in a liquid-tight manner. 2. The pressure-accumulation type fuel injection according to claim 1, wherein the external communication hole penetrates the pressure accumulator in a straight line, and the axis of the external communication hole is in a twisted positional relationship with the axis of the accumulator. apparatus. 3. A structure in which a screw portion of the member to be fastened is screwed to a screw portion formed on an inner wall of the large-diameter hole,
The accumulator type fuel injection device according to claim 1, wherein a sheet portion of the member to be fastened contacts an inclined surface of the accumulator when the screw connection is completed. 4. The accumulator type fuel injection device according to claim 1, wherein the member to be fastened is for mounting a pipe connected to an injector.