JPS59206672A - Fuel injection valve of internal-combustion engine - Google Patents

Abstract

PURPOSE:To control fuel injection angle by forming a guide part in projection or a grooves which extend in the direction of inclination with respect to the direction of axis of a needle valve, onto at least one among the inner peripheral surface of a fuel jetting-out opened part and the outer peripheral surface of the needle valve. CONSTITUTION:In a needle valve 1, the amount of lift in case of a little amount of injection is relatively small, and the second throttle part 4 is positioned under the throttle part 8 of an opened part 6 having a number of grooves 9 cut in inclination with respect to the direction of axis, and the gap between the needle valve 1 and the throttle part 8 is small in this state, and the passing fuel scatters outside, guided by the groove 9, and the injection angle increases. While, in case of a large amount of fuel jetted-out, the amount of lift is large, and the second throttle part 4 is positioned over the throttle part 8 and the gap is increased, and fuel is jetted-out at a small injection angle, without substantially being influenced by the grooves 9. Thus, proper mixed-gas can be obtained in a wide range of operation.

Description

TECHNICAL FIELD The present invention relates to a fuel injection valve that supplies fuel into a combustion chamber of a diesel engine.

Prior Art In a conventional bottle-type injection nozzle, the fuel injection angle is determined by the shape of the tip of the needle valve, and is constant depending on the lift amount of the needle valve. Typically, this injection angle is small, about 4 degrees, to ensure sufficient mixing of fuel and air at high engine speeds and high loads.

However, at low speeds and low loads in engines with small needle valve lifts, fuel and air are not mixed sufficiently, which not only does not provide sufficient engine output, but also poses a risk of worsening exhaust gas emissions (especially 11C). There is.

Here, in order to solve the problem at low speed and low load, if the spray angle is widened (contrary to the above, the fuel will not be injected with sufficient strength at high speed and high load, and the mixture will not be properly mixed). (M
The problem arises that it is not possible to In other words, in the conventional fuel injection valve, it was necessary to sacrifice the formation of an air-fuel mixture in either a low speed range or a high speed range.

Purpose of the Invention In view of the above points, an object of the present invention is to obtain a fuel injection valve that can control the fuel injection angle so that a suitable mixture can always be obtained over a wide range of engine operation. .

Structure of the Invention The fuel injection valve for an internal combustion engine according to the present invention has an injector in the axial direction of the needle valve on at least one of the inner circumferential surface of the opening through which fuel is injected and the outer circumferential surface of the needle valve that can face the inner circumferential surface. It is characterized by extending in a direction inclined to the

Example The present invention will be explained below with reference to the illustrated embodiments.

1 to 4 show a first embodiment of the present invention, in which a needle valve 1 is housed in a housing 2 so as to be able to reciprocate, and a valve body portion formed below the housing 2 has a cylindrical first slot. a truncated cone-shaped second throttle section 4 connected below the first throttle section 3; a second throttle section 4 provided below the second throttle section 4; The tip portion 5 also has a tapered truncated conical shape. An opening 6 formed in the housing 2 has a lower peripheral edge 7 chamfered in a tapered shape, and an upper part thereof forms a constricted part 8.

As shown in FIG. 2, this throttle portion 8 is provided with a large number of grooves 9 that are substantially parallel to each other and are inclined with respect to the axial direction of the needle valve 1.

The needle valve 1 can be inserted into the opening 6. When injecting a small amount of fuel, the needle valve 1 is in the position shown in FIG. 3 with a relatively small lift amount, and the second throttle part 4
is located below the constriction part 8. In this state, the fourth
As shown in the figure, the gap between the needle valve 1 and the throttle part 8 is relatively small, and the fuel passing between them is guided by the groove 9 and scattered outward, resulting in a large spray angle.

On the other hand, when injecting a large amount of fuel, the needle valve 1 has a relatively large amount of reflux ha and is in the position shown in FIG. To position. In this state, the gap between the needle valve 1 and the throttle part 8 is relatively large, and the fuel is injected at a small spray angle similar to a crowded screw nozzle without being substantially influenced by the groove 9.

5 and 6 show a second embodiment of the present invention. In this embodiment, a protrusion 10 is provided on the throttle portion 8 and is inclined about 10 degrees with respect to the axial direction of the needle valve I, and the protrusion 10 is used to guide the fuel. However, in the first embodiment, the fuel was guided through the groove 9, and the protrusion 10 essentially performs the same function as the groove 9. Furthermore, in the second embodiment, the tip portion 5 of the needle valve 1 has a larger diameter at the bottom.

It has a circular & (C trapezoidal shape). This makes it possible to further increase the fuel 1IIf fog angle when the needle valve 1 is less lifted as shown in FIG.

FIG. 7 shows a third embodiment, which differs from each of the above embodiments.
A configuration is shown in which an inclined groove 11 for guiding fuel is carved on the outer surface of the cylindrical portion 3 of the needle valve 1.

Also with this configuration, when the lift amount of the needle valve 1 is small, the fuel spray angle can be increased. In other words,
When the lift amount is small, the groove 11 faces the throttle part 15B, so the fuel passing between the needle valve 1 and the throttle part 8 flows through the groove 1.
1 and scatters outward, increasing the spray angle.

Note that the same effect can be obtained even if a projection is provided in place of the groove 11 as in the second embodiment. Further, in this third embodiment, the lower peripheral edge of the opening 6 is not chamfered, and the needle valve 1 has substantially the entire tip 5 protruding outward from the housing 2 at the lowest position.

In the first and second embodiments, the lower peripheral edge of the C1 opening 6 is chamfered into a tapered shape, but this shape is not essential. For example, as shown by the broken line P in FIG. It may be chamfered, or it may be expanded stepwise over the entire circumference as shown by the dashed line 0.

According to the present invention, the needle valve glue 71-
Since the fuel spray angle can be increased when the rift is small, and the fuel spray angle can be decreased when the rift is large, it is possible to always provide a good fuel supply regardless of the operation Φr state.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the first embodiment, Fig. 2 is an enlarged sectional view of the opening n part, and Fig. 3 is a rift 1-1M of the needle valve.
FIG. 4 is a cross-sectional view showing a state in which the TV − of FIG.
5 is a sectional view taken along the TV line, FIG. 5 is a sectional view showing the second embodiment, FIG. 6 is a sectional view taken along the Vl-Vl line in FIG. 5, and FIG. 7 is a sectional view showing the third embodiment. be. l... Needle valve, 2... Housing, 6... Opening, 7... Periphery, 9, 11... Groove, 10...
protrusion. Figure 5 Figure 7 6)

Claims (1)

[Claims] 1. A needle valve reciprocably housed in a housing can be inserted into an opening formed in the housing, and the needle valve can be inserted into an opening formed in the housing, and the needle valve can be inserted into an opening formed in the housing, and the needle valve can be inserted into an opening formed in the housing, and the needle valve can be inserted into an opening formed in the housing, and the needle valve can be inserted into an opening formed in the housing. In a fuel injection valve for an internal combustion engine that changes the amount of fuel injected from an opening, the needle valve is provided on at least one of the inner circumferential surface of the opening and the outer circumferential surface of the needle valve that can be opposed to the inner circumferential surface of the needle valve. When the lift amount of the needle valve is relatively small, the inner circumferential surface and the outer circumferential surface face each other, and the fuel The fuel is guided by the guide part and injected at a large spray angle, and when the reflux amount of the needle valve is relatively large, the fuel is not substantially guided by the guide part and is injected at a small spray angle. Features of fuel injection valves for internal combustion engines. 2. The fuel injection valve according to claim 1, wherein the peripheral edge of the opening on the outer peripheral side of the housing is chamfered in a tapered manner. 3. The fuel injection valve according to claim 1, wherein the periphery of the opening on the outer periphery of the housing is rounded and chamfered. 4. The fuel injection valve according to claim 1, wherein the periphery of the opening on the outer periphery of the housing is expanded in a stepped manner over the entire circumference.