JPS5954766A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To obtain pressure accumulating and damping effects through an additional part of volume and prevent the intrusion of combustion gas into the end of a nozzle, by providing, in the main unit of a valve, the additional part of volume communicated to a fuel supply path in the valve through a fine hole or the like. CONSTITUTION:In a fuel injection valve, when the pressure of fuel oil in a nozzle chamber 1 decreases lower than the pressure of combustion gas in a cylinder, the combustion gas intrudes into the valve from the cylinder, and the intruding combustion gas is allowed to flow through the gap between a nozzle valve 2 and a nozzle holder 3 and through a spring chamber 4, appearing as bubbles in a leakage oil pipe 5. An additional part of volume 11 is provided to be communicated through a fine hole 10 in the nozzle holder 3 located in the inlet part of a fuel supply path 9 communicated to a high pressure fuel line 6 of said valve. A pressure wave from a fuel injection pump and a reflective wave from the part of a nozzle 8 are absorbed in this additional part of volume 11, thus increasing the residual pressure in a pipe. In this way, the combustion gas can be prevented from intruding into the end of the nozzle 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection valve for an internal combustion engine, which is provided with a predetermined volume to prevent combustion gas from entering the fuel injection valve.

Combustion gas enters the fuel injection valve installed in the internal combustion engine when the fuel oil pressure inside the fuel injection valve, especially the nozzle chamber 1, becomes lower than the combustion gas pressure inside the cylinder in the conventional example shown in FIG. This is a phenomenon in which combustion gas intrudes into the fuel injection valve from inside the cylinder. When the amount of intruding combustion gas increases, the intruding combustion gas passes through the gap between the nozzle valve 2 and the nozzle holder 6 and the spring chamber 4 shown in FIG. The oil leaks out in the form of bubbles 3 in the oil leakage pipe 5. This phenomenon may cause the nozzle valve 2 to slide poorly, possibly resulting in seizure.

Therefore, in the invention of Utility Model Publication No. 53-24581 concerning a device for preventing combustion gas from entering into a fuel injection valve, a high-pressure fuel pipe is installed between the fuel injection valve shown in Fig. 1 and a fuel injection pump (not shown). 6 or during fuel injection intervention [i
A standard volume consisting of a pressure accumulator 7 is provided on the side of the high-pressure fuel pipe 6 through a restriction, which absorbs pressure waves from the fuel injection pump and reflected waves from the nozzle nozzle 8, reducing the residual pressure inside the pipe. This increases the so-called damper effect by suppressing pressure fluctuations in the pipe after the nozzle valve 2 is opened, thereby preventing combustion gas from entering while preventing high-order injection in the entire operating range.

In other words, if the pressure in the injection section 18 suddenly drops when the fuel injection valve is throttling the injection valve, the high pressure stored in the pressure accumulation chamber 7 will propagate, preventing an excessive pressure drop and reducing the pressure to the nozzle tip. It becomes ζ- through which gas intrusion is prevented.

-4fc, height 1- between the fuel injection pump and fuel injection valve
1 (It is also known that the invention was made in April 1172, 1972, regarding a fuel injection control device that controls the injection by providing a chamber in the combustion pipe O through a narrow passage.1 1 - However, in both cases, the pressure accumulation chamber 7, l (
Since the hollow chamber is provided, there is a problem that there is no additional volume effect, and the number of processed parts is small, which increases the production cost3.Therefore, the present invention solves the above-mentioned conventional problems. By providing an additional volume that communicates with the fuel supply path near the nozzle jet 1 in the fuel injection valve, gas intrusion into the tip of the nozzle jet 1 is prevented. The purpose is to provide an inexpensive fuel injection valve. .

That is, the fuel injection valve of the present invention is constructed by providing an additional volume in the fuel injection valve body portion, which communicates with the fuel supply passage within the fuel injection valve through a small hole or slit. Hereinafter, a detailed description of the present invention will be given with reference to the drawings.
In each of the embodiments and the conventional example shown in FIG. 1, the same parts are indicated by the same part number. 1. In the first embodiment of the present invention shown in FIG. 2, it is almost the same as the conventional example shown in FIG. In this fuel injection valve, as shown in FIG. 3, which is a plan cross-sectional view taken along the line II in FIG. The inlet [-] portion of the fuel supply passage 9 is communicated with through a small hole 1o, and an additional volume 11 is provided. There is.

In general, in the case of Bosch type fuel injection valves, the residual pressure in the pipe is low and the pressure fluctuations after opening are large, resulting in combustion gas intrusion.
Although it is easy to understand, as mentioned above, in the present invention, the fuel supply path 9 is provided with the regular volume 11 that communicates with the small hole 1o. It absorbs the reflected waves, increases the residual pressure in the pipe, and suppresses the abnormal rise in the initial oil pressure applied to the nozzle bar I1..7'2, exerting a so-called damper effect, thereby achieving high-order injection in the entire operating range. Although it is possible to prevent the combustion gas from entering the tip of the jet 1-18, in the present invention, this additional volume 11 is used as the jet 1-18 of the nozzle.
It has been experimentally confirmed that it is particularly effective in preventing combustion gas intrusion, since it is provided at the 18th position.

Next, FIG. 1 is a side sectional view of the main part of the fuel injection station in Embodiment 2 of the present invention, FIG. 5 is a plan view of FIG. 1, and FIG. 6 is a II-II force direction in FIG. 5. 2 is a side sectional view of Embodiment 1, in which an additional volume 11 communicating with a fuel supply passage 9 via a slit 14 is provided in a nozzle holder 6, which is a main body portion of a fuel injection valve having a configuration substantially similar to that of Embodiment 1. Although it is made of ZvO and has the same effect as in Example 1, the dowel pin holes are shown by 12 in FIG. .

Embodiment 3 shown in FIG. 7 is similar to Embodiment 2 in that the additional volume 11 provided inside the nozzle holder 6 and the fuel supply passage 9 are communicated with each other through a small hole 10. Embodiment 4 The figure is a sectional side view of the main part of a fuel injection valve in Embodiment 4 of the present invention.
The figure is a plan view of Fig. 8, and Fig. 10 is III-1 of Fig. 8.
In Example 4, the lower part of the stem part of the nozzle valve 2, which is fitted with the nozzle boulder 6 with a slight clearance, is placed in the nozzle holder 6 in an annular shape. This additional volume 11 is communicated with the nozzle chamber 1 which communicates with the fuel supply path 9 through the slit 14, and the same effect as in Example 1 can be obtained. Since the nozzle valve 2 is light in weight, its movement during opening and closing becomes smooth. The chamber 1 may be communicated with the chamber 1 through the pore 10, and as in Embodiment B of FIG. The diameter d2 of the nozzle valve 2 in the part that partitions it from the chamber 1 is d2<dl, and 2
It is also possible to provide a clearance and communicate the additional volume 11 with the nozzle chamber 1 communicating with the fuel supply path 9 through this clearance.
It is also effective to form a volume 11 of the nozzle vane on the outer periphery of the nozzle vane 2 and the rudder 6 side, and to communicate with the fuel supply passage 9 full through the slit 14. , therefore,
In the fuel injection valve of the present invention, an additional volume is provided in the fuel supply passage at a position near the nozzle injection part [1] where combustion gas easily enters. ,
A) It is extremely effective in preventing gas intrusion due to the pressure accumulation inherent in the added volume.

Moreover, the fuel injection valve of the present invention has the advantage that its regular volume structure is simple and its production cost is low1.The present invention can be effectively applied to fuel injection valves for internal combustion engines. 3. Can

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a conventional fuel injection valve, FIG. 2 is a side sectional view of a fuel injection valve according to Embodiment 1 of the present invention, and FIG. 3 is a flat side view of the I-1 force direction in FIG. 4 is a side sectional view of a main part of a fuel injector according to Embodiment 2 of the present invention, FIG. 5 is a plan view of FIG. 4, and FIG. 6 is a side in the force direction of FIG. 5. 7 is a side sectional view of a main part of a fuel injection valve according to Embodiment 3 of the present invention, and FIG. 8 is a sectional side view of a main part of a fuel injection valve according to Embodiment 4 of the present invention. is a plan view of FIG. 8, FIG. 10 is a plan sectional view in the direction ■-■ of FIG. 8, FIG.
13 is a sectional side view of a main part of a fuel injection valve according to a sixth embodiment of the present invention, and FIG. 13 is a side sectional view of a main part of a fuel injection valve according to a seventh embodiment of the present invention. 6... Nozzle boulder-16... High pressure fuel pipe line, 8...
... Jet [1,9... Fuel supply path, 1o... Pore, 1
1... standard volume, 14... slit. 8 Agents Patent Attorney Makoto Ogawa − Patent Attorney Masaru Noguchi Patent Attorney Kazuhiko Saishita

Claims (1)

[Claims] A fuel injection valve characterized in that an additional volume that communicates with a fuel supply passage within the fuel injection valve through a narrow or slit is disposed within the fuel injection valve body.