JPH0491365A - Fuel injection nozzle - Google Patents

Abstract

PURPOSE:To improve injection efficiency while preventing fuel from its leak to a combustion chamber after finishing fuel injection by bringing an opening/closing cock into contact with an end face of a hollow cylinder, detaching this opening/closing cock from the end face at injection time of fuel, and injecting the fuel from a circumferential injection hole between the end face and the opening/closing cock. CONSTITUTION:A valve 2 is inserted to the inside of a holder 1 while drilling a pipe path 11 in a closed side of the cylindrical holder 1 whose one end is closed, and a retainer 21 is fixedly connected to an insertion side end part of the valve 2 and energized always in a valve closing direction by extending force of a spring 22. An oil reservoir 23, with the axial diameter thin formed, is provided in the other end peripheral surface of the valve 2, and a disc-shaped opening/closing cock 24 is integrally formed in the other end part of this valve 2. Further, an oil pipe 25 is drilled in the valve 2 from the insertion side end part to a position in the vicinity of the other end, and a plurality of communication pipes 26, communicating with the oil reservoir 23 and the concerned oil pipes 25, are drilled in the point end part of the oil pipe 25. A body 3 is arranged between the opening/closing cock 211 and the spring 22, in the periphery of the valve 2, and the opening/closing cock 24, which is brought into press contact with a lower part end surface of the body 3, closes the oil reservoir 23 relating to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a nozzle for injecting fuel into a combustion chamber, and particularly to a fuel injection nozzle having a large nozzle opening area.

(Prior Art) A conventional fuel injection nozzle has a cavity (sack portion) at the tip of a bottomed cylindrical body into which high-pressure fuel is supplied, and a cavity (sack portion) is provided on the peripheral wall of the suck portion for injecting fuel into a combustion chamber. A nozzle hole is drilled.

Then, the tip of the needle valve disposed inside the bottomed cylinder is seated on a tapered valve seat provided in a communicating area between the inside of the bottomed cylinder and the sack part, and fuel is supplied to the sack part. Preventing the influx. The needle valve is always urged in the seating direction by a spring force, but when high-pressure fuel is supplied from the fuel pump into the bottomed cylinder, the pressure of the fuel acts on the needle valve, causing the spring force to increase. drive the twenty-one dollar valve against the Then, the fuel inside the bottomed cylinder passes through the gap formed between the tip surface of the needle valve and the valve seat and flows into the sack portion. Then, the fuel that has flowed into the sack portion is injected into the combustion chamber through the injection holes provided in the sack portion.

When the supply of high-pressure fuel from the fuel pump is stopped, only the spring force remains on the needle valve, so
The needle valve is seated on the valve seat again and fuel injection is stopped.

By the way, the fuel injection amount is increased or decreased depending on the load of the engine, and a large amount of fuel is injected when the load is high.

(Problem to be Solved by the Invention) For example, if the injection duration is extended, fuel injection will continue even when the temperature inside the combustion chamber has decreased, and this will reduce the amount of hydrocarbons (HC) contained in the exhaust gas. ) and the amount of black smoke increases. Therefore, even when injecting a large amount of fuel, the injection duration cannot be extended.

By the way, in order to increase the amount of fuel that can be injected per unit time, that is, to increase the injection efficiency, it is necessary to increase the discharge pressure of the fuel pump and expand the fuel flow path such as the injection hole of the fuel injection nozzle. There are many things you can do.

Among the above, increasing the discharge pressure of the fuel pump is
There are problems with the sealing performance of various parts of the fuel injection system, and it is not possible to significantly increase the discharge pressure from the current level.

In addition, although it is effective to expand the fuel flow path, especially the opening area of the nozzle hole, expanding the opening area of the nozzle hole leads to an increase in the volume of the sac portion, and the above-mentioned needle valve Since the amount of fuel remaining in the sac portion after the fuel is seated increases and leaks into the combustion chamber, there is a limit to the expansion of the opening area of the nozzle hole.

The present invention has been made in view of the above points, and eliminates fuel leaking into the combustion chamber after fuel injection is completed.
The present invention aims to provide a fuel injection nozzle with increased injection efficiency by expanding the opening area of the nozzle hole.

(Means for Solving the Problems) According to the present invention, there is provided a hollow cylindrical body whose one end face opens into a combustion chamber and which guides high-pressure fuel into the combustion chamber, and an opening on one end face of the hollow cylindrical body that opens and closes. a closing means for pulling the stopcock from the hollow interior of the hollow cylindrical body to close the opening; and an opening for removing the stopper from the opening against the pulling force of the closing means and opening the opening. It is possible to provide a fuel injection nozzle characterized in that it has a means.

(Function) In the fuel injection nozzle of the present invention, the stopper is brought into contact with the end face of the hollow cylindrical body through which fuel is guided into the hollow part, the opening of the hollow cylinder is closed, and the stopcock is closed during fuel injection. The valve is separated from the end face, and fuel is injected from a circumferential injection hole formed between the end face and the valve.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a fuel injection nozzle according to the present invention.

Reference numeral 1 denotes a holder, which is formed into a cylindrical shape with one end closed. A pipe F1811 that communicates the inside and outside of the holder 1 is bored on the closed side of the holder 1. A lid stopper 12 is disposed inside the holder 1 to regulate the opening amount of the injection hole, which will be described later. The lift stopper 12 is formed into a thin cylindrical shape, and is in contact with the inner wall of the hollow portion of the holder 1.

Further, a valve 2 is inserted into the inside of the holder 1, and a retainer 21 is connected and fixed to the insertion side end of the valve 2. □The retainer 21 is sandwiched between the closed inner end surface of the holder 1 and the lift stopper 12, and is slidably in close contact with the inner circumferential surface of the holder I. Further, the retainer 21 is always urged toward the inner end surface on the closed side by the expanding force of the spring 22.

An oil reservoir 23 is provided on the outer circumferential surface of the other end of the valve 2 with a narrow shaft diameter, and a disc-shaped opening/closing plug 24 is formed integrally with the valve 2 at the other end of the valve 2. There is. Further, an oil pipe 25 is bored through the valve 2 from the insertion side end to a position near the other end, and a plurality of connections are provided at the tip of the oil pipe 25 to communicate the oil reservoir 23 and the oil pipe 25. A tube 26 is drilled.

A body 3 is disposed on the outer periphery of the valve 2 between the open/close plug 24 and the spring 22, and the body 3 is fixed by a body cover 4. still,
A spring 31 is disposed between the body 3 and the spring 22.

Next, the operation of the fuel injection nozzle with the above configuration will be explained.

FIG. 2 is a partial sectional view of the tip portion during fuel injection.

Normally, the valve 2 is urged upward in the figure by the expanding force of the spring 22 acting through the retainer 21. Therefore, the stopper 24 is pressed against the lower end surface of the body 3, and the oil reservoir 23 is insulated from the outside.

Then, at fuel injection timing, a fuel pump (not shown) discharges high-pressure fuel to the fuel injection nozzle. High-pressure fuel discharged from the fuel pump passes through a conduit 11 and is guided into the holder 1. Incidentally, since the retainer 21 is in close contact with the inner peripheral surface of the holder 1, the pressure of fuel from the fuel pump acts on the upper surface of the retainer 21.

Since the acting force due to the fuel pressure is set to be greater than the expansion force due to the spring 22, the nozzle 2 is driven downward.

Then, the stopper 24 separates from the lower end surface of the body 3, and the oil reservoir 23 opens to the outside. Since the opening 5 is formed in a circumferential shape, it functions as an injection hole having a large opening area.

By the way, the shape of the opening 5 is not limited to that of the above-mentioned embodiment, and may have other shapes.

FIG. 3 is a partial sectional view showing another shape of the opening.

In this embodiment, a piece 6 is added to the above-described embodiment, so that the opening 7 has a circumferential shape divided into a plurality of parts. By adding the piece 6, the fuel injection direction can be regulated to a desired direction.

Although the embodiments of the present invention have been described in detail above, various different embodiments can be easily constructed without departing from the spirit of the invention, and therefore, the present invention is not limited to any limitations other than those set forth in the claims. , and is not limited to any particular implementation.

(Effects of the Invention) As explained above, according to the present invention, a stopper is brought into contact with the end face of the hollow cylinder through which fuel is guided into the hollow part, the opening of the hollow cylinder is closed, and the fuel is At the time of injection, the valve is removed from the end face, and the fuel is injected from the circumferential injection hole formed between the end face and the valve, so that the fuel does not leak into the combustion chamber after fuel injection is completed. It is possible to provide a fuel injection nozzle in which the opening area of the hole can be expanded and therefore the injection efficiency can be set to a high level.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a fuel injection nozzle according to the present invention, FIG. 2 is a partial sectional view of the tip portion during fuel injection, and FIG. 3 is a partial sectional view showing another shape of the opening. It is. 1...Holder, 2...Nozzle, 3...Body,
4...Body cover 5.7...Opening, 6...
・Pieces. Patent applicant: Isuf Ceramics Research Institute Co., Ltd.
Patent Attorney Minoru Tsuji “0 ■

Claims (4)

[Claims] (1) A hollow cylindrical body whose one end face opens into a combustion chamber and guides high-pressure fuel into the combustion chamber, and a stopper that opens and closes the opening on one end face of the hollow cylindrical body from the hollow interior of the hollow cylinder. A fuel injection nozzle characterized by having a closing means for pulling the opening to close the opening, and an opening means for separating the stopcock from the opening and opening the opening against the pulling force of the closing means. . (2) The fuel injection nozzle according to claim 1, wherein the opening/closing plug is a disc member that abuts the one end surface. (3) The fuel injection nozzle according to claim (1), wherein the traction force is a tension force generated by a spring. (4) The fuel injection nozzle according to claim (1), wherein the opening means is operated by the pressure of the high-pressure fuel.