JPH0519559U - Fuel injection nozzle - Google Patents

Abstract

(57) [Summary] [Structure] The injection hole 15 is composed of two small holes 151 and 152. One end of each of the two small holes 151 and 152 is opened on the inner peripheral surface of the blind hole 14, and one end of the outer opening is opened on the outer surface of the nozzle body 1. Each small hole 151,1
The openings inside 52 are separated from each other in the direction of the axis L, and the openings outside intersect with the outer surface of the nozzle body 1. Further, the small diameter portion 23 of the valve body 2 is formed with an annular protruding portion 233 which is slidably fitted to the inner peripheral surface of the fuel introduction hole 13. The annular projecting portion 233 has a flattening portion 234 for communicating the fuel introducing hole 13 with the auxiliary fuel reservoir 18.
To form. [Effect] The injection direction of the fuel injected from the injection hole 15 can be changed according to the lift amount of the valve body 2. If the lift amount of the valve body 2 is constant, the fuel injection amount injected from the injection hole 15 can be made constant without varying for each lift of the valve body 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a fuel injection nozzle for injecting fuel into a combustion chamber of a diesel engine.

[0002]

[Prior Art]

 A conventional fuel injection nozzle is shown in FIG. 6 (see Japanese Patent Application Laid-Open No. 1-92569). The fuel injection nozzle includes a nozzle body 1 and a valve body 2. Inside the nozzle body 1, the valve sliding hole 11, the fuel reservoir 12, the fuel introducing hole 13 having a diameter smaller than that of the valve sliding hole 11, and the tapered tapered hole are arranged in this order from the upper end to the lower end on the axis L thereof. A blind hole 14 having a shape is formed, and a plurality of injection holes 15 are formed at the lower end portion of the nozzle body 1. The plurality of injection holes 15 are arranged point-symmetrically with respect to the axis L, the inner ends thereof open to the inner peripheral surface of the blind hole 14, and the outer ends thereof open to the outer surface of the nozzle body 1. is doing. Reference numeral 16 is a high-pressure passage for supplying the fuel, which is pumped from a fuel injection pump (not shown), to the fuel reservoir 12.

The valve body 2 has a large-diameter portion 21 slidably fitted in the valve sliding hole 11 in order from the upper end side to the lower end side thereof, a pressure receiving portion 22 facing the fuel reservoir 12, and a fuel passage hole. A small-diameter portion 23, which is inserted with a gap, and a cover portion 24 having a tapered shape are formed in the groove 13. The taper of the cover portion 24 is slightly larger than that of the blind hole 14. Therefore, when the valve body 2 is moved downward by the nozzle spring (not shown), the intersection of the small diameter portion 23 and the cover portion 24 is seated on the inner peripheral surface of the blind hole 14. That is, in this fuel injection nozzle, the intersection of the small diameter portion 23 and the cover portion 24 is the valve portion 25, and the inner peripheral surface of the blind hole 14 in which this valve portion 25 is seated is the valve seat 17. Is becoming The taper degree of the cover portion 24 may be equal to the taper degree of the blind hole 14.

By the way, in the fuel injection nozzle having the above structure, when the fuel is injected into a wide range of the combustion chamber and the lift amount of the valve body 2 is constant, the injection amount injected from each injection hole 15 is always constant. It is required to be constant. This is because by injecting fuel over a wide range, the air in the combustion chamber can be used efficiently, and the amount of injection from each injection hole can be prevented from varying from injection to injection to improve the combustion state. It is an attempt to make them uniform.

[0005]

[Problems to be solved by the device]

 However, in the conventional fuel injection nozzle, it has not been possible to sufficiently meet the demand for injecting the fuel in a wide range and uniformly injecting the fuel from the injection holes. That is, in order to inject the fuel into a wide range, the injection direction may be changed during the injection period from the start to the end of the injection. However, in the conventional fuel injection nozzle, the injection direction of the fuel is constant and cannot be changed. For this reason, the fuel could not be injected over a wide range, and the efficiency of using the air in the combustion chamber was inevitably low. This point was especially problematic when the fuel injection amount was high and the load was high.

Further, since the small-diameter portion 23 of the valve body 2 is thin and long, when the valve portion 25 separates upward from the valve seat 17 (hereinafter referred to as a lift), the valve body 2 is, as shown in FIG. The axis line of the cover portion 24 may be deviated from the axis line L by the width σ. In such a case, the size of the gap between the cover portion 24 and the inner peripheral surface of the blind hole 14 becomes uneven. The injection amount from the injection hole 15 located on the side where the gap is small becomes smaller than the injection amount when the valve body 2 is not shaken. On the contrary, a larger amount of fuel is injected from the injection hole 15 located on the side where the gap is larger than when there is no runout. As described above, the valve body 2 sometimes swings during its lift, which causes a problem that the amount of fuel injected from the injection hole 15 varies depending on the lift of the valve body 2.

The present invention has been made to solve the above problems, and can change the injection direction of fuel, and moreover, the injection amount from the injection hole does not vary depending on the lift of the valve element, and It is an object of the present invention to provide a fuel injection nozzle that can always maintain a constant lift amount of the body so that a favorable combustion state can be realized.

[0008]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention comprises a nozzle body and a valve body slidably provided inside the nozzle body, and the inside of the nozzle body has its axis on one end side. A valve sliding hole, a fuel reservoir, a fuel introduction hole, a valve seat, and a tapered blind hole are formed sequentially toward the other end, and one end is opened on the inner peripheral surface of the blind hole. A large diameter portion that is slidably fitted into the valve sliding hole sequentially from one end side to the other end side of the valve body; A small diameter part that penetrates the reservoir and is inserted into the fuel introduction hole with a gap, a valve part that sits on the valve seat and blocks the blind hole from the fuel introduction hole, and the same or slightly smaller than the blind hole In a fuel injection nozzle with a tapered cover The injection hole is composed of a plurality of small holes. Two of the small holes have openings in the blind holes which are spaced apart from each other in the axial direction of the blind hole, and the openings in the outer surface of the nozzle body are the same. The guide portion is arranged so as to intersect in the vicinity of the outer surface, and at least one of the inner peripheral surface of the valve fuel introduction hole and the outer peripheral surface of the small diameter portion suppresses runout in a direction orthogonal to the axis of the small diameter portion. Is formed.

[0009]

[Action]

 When the valve body lifts, fuel flows between the cover portion of the valve body and the inner peripheral surface of the blind hole, and is injected from each small hole of the injection hole. The fuel injected from each small hole collides with each other immediately before or after the injection because the small holes intersect each other near the outer surface of the nozzle body. As a result, the entire fuel injected from each small hole goes in a direction that combines the injection directions of the fuel injected from each small hole.

Here, the lift amount of the valve body is small at the beginning of fuel injection. When the lift amount of the valve body is small, the gap between the cover portion of the valve body and the inner peripheral surface of the blind hole is small, and the throttle effect due to the gap is large. Due to this throttling effect, the pressure inside the blind hole increases on the valve seat side and decreases on the tip side of the blind hole. Therefore, a large amount of fuel is injected from a small hole (hereinafter referred to as an upper small hole) whose inner opening is located on the valve seat side, and the inner opening is located on the leading end side of the blind hole ( Hereinafter, the amount of fuel injected from the lower small hole will decrease. Therefore, the injection direction of the entire fuel injected from the injection holes is close to the injection direction of the fuel injected from the upper small holes.

On the other hand, the lift amount of the valve body is large after the middle period of fuel injection. When the lift amount of the valve disc is large, the gap between the cover of the valve disc and the inner peripheral surface of the blind hole is large. Through the inner peripheral surface of the blind hole and without any resistance toward the front end of the blind hole. In this case, since the tip of the blind hole is closed, the fuel will stay at the tip of the blind hole. Therefore, the pressure inside the blind hole is high on the tip side of the blind hole and low on the valve seat side. As a result, the injection amount from the upper small hole decreases and the injection amount from the lower small hole increases. Therefore, the injection direction of the entire fuel injected from the injection holes is close to the injection direction of the lower small holes.

Further, the guide portion prevents the valve body from swinging. Therefore, the injection amount of fuel injected from the injection hole does not vary for each lift of the valve body, but is always constant if the lift amount of the valve body is constant.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. In the following embodiments, the same parts as those in the above-mentioned conventional example are designated by the same reference numerals and the description thereof will be omitted.

1 (A), (B) and FIG. 2 show an embodiment of the present invention. In this embodiment, as shown in FIG. 1 (A), the lower end of the fuel introducing hole 13 is The auxiliary fuel reservoir 18 is formed by expanding the diameter of the portion.

Further, each injection hole 15 is composed of two small holes 151, 152 having the same inner diameter. Of course, the inner ends of the small holes 151 and 152 open to the inner peripheral surface of the blind hole 14, and the outer ends open to the outer surface of the nozzle body 1.

The openings of the small holes 151, 152 are located at the same position in the circumferential direction of the axis L, but are apart from each other in the direction of the axis L, that is, in the lift direction of the valve body 2. In this fuel injection nozzle, the opening of the small hole 151 is located close to the valve seat 17, and the opening of the small hole 152 is located away from the valve seat 17 on the leading end side of the blind hole 14. ..

On the other hand, to describe the outside opening of each small hole 151, 152, the outside opening of each small hole 151, 152 intersects with the outer surface of the nozzle body 1. Particularly, in this embodiment, the axes of the small holes 151 and 152 intersect with each other on the outer surface of the nozzle body 1, and both holes 151 and 152 are opened at the same location on the outer surface of the nozzle body. However, as long as the holes 151 and 152 intersect with each other on the outer surface of the nozzle body 1, the axes of the holes 151 and 152 may be slightly separated without intersecting each other, or each axis may be separated from the outer surface of the nozzle body 1. It is also possible to intersect at a place that is slightly outward or inward.

The small-diameter portion 23 of the valve body 2 is composed of an upper shaft portion 231 above the sub fuel reservoir 18 and a lower shaft portion 232 having a diameter smaller than the upper shaft portion 231. An annular protruding portion (guide portion) 233 that is slidably fitted into the fuel introduction hole 13 is formed at the lower end portion of the upper shaft portion 231. A flattened portion 234 extending from the upper end to the lower end is formed on the annular protrusion 233. A passage 235 is formed by the flattened portion 234 and the inner peripheral surface of the fuel introduction hole 13. The fuel introduction hole 23 and the auxiliary fuel reservoir 18 are communicated with each other through the passage 235. In addition, in this embodiment, in addition to the pressure receiving portion 22, the lower end surface of the upper shaft portion 231 facing the sub fuel reservoir 18 also serves as a pressure receiving portion 235 for lifting the valve body 2 under the pressing force of the fuel. There is.

In the fuel injection nozzle having the above structure, when the fuel is pumped from the fuel injection pump to the fuel reservoir 12 through the high pressure passage 16, the valve body 2 lifts against the biasing force of the nozzle spring. Then, the fuel in the fuel pool 12 flows into the auxiliary fuel pool 18 through the passage 235 and the gap between the inner peripheral surface of the fuel introduction hole 13 and the outer peripheral surface of the upper shaft portion 231. Then, it passes through between the cover portion 24 and the inner peripheral surface of the blind hole 14 and is jetted from the jet hole 15.

Here, the lift amount of the valve body 2 is small at the beginning of fuel injection. When the lift amount of the valve body 2 is small, the gap between the cover portion 24 of the valve body 2 and the inner peripheral surface of the blind hole 15 is small, and the throttling effect due to the gap is large. Due to this throttling effect, the pressure inside the blind hole 14 increases on the valve seat 17 side and decreases on the lower end side of the blind hole 14. Therefore, the amount of fuel injection from the small hole 151 whose inner opening is located on the valve seat 17 side increases, and the amount of fuel injection from the small hole 152 whose inner opening is separated from the valve seat 17 decreases. .. Therefore, the injection direction of the entire fuel injected from the injection holes 15 is close to the injection direction of the fuel injected from the small holes 151.

On the other hand, after the middle period of fuel injection, the lift amount of the valve body 2 is large. When the lift amount of the valve body 2 is large, the gap between the cover portion 24 of the valve body 2 and the inner peripheral surface of the blind hole 15 is large, so that the throttling effect due to it is hardly generated, and the fuel is used as the valve body 2 Passing through the cover 24 and the inner peripheral surface of the blind hole 15 toward the lower end of the blind hole 14 without any resistance. In this case, since the lower end of the blind hole 14 is closed, the fuel stays at the lower end of the blind hole 14. Therefore, the pressure inside the blind hole 14 increases on the lower end side and decreases on the upper end side (valve seat 17 side). As a result, the injection amount from the small hole 151 decreases and the injection amount from the small hole 152 increases. Therefore, the injection direction of the entire fuel injected from the injection holes 15 is close to the injection direction of the small holes 152.

In this way, the injection direction of the entire fuel injected from the injection holes 15 changes according to the lift amount of the valve body 2, so the fuel is injected into the combustion chamber over a wide range. In particular, when the load is high, the lift amount of the valve body 2 is large, so the change in the fuel injection direction is large. Therefore, the fuel is injected in a wider range. Therefore, the fuel can be burned in good condition.

As is clear from the fact that the injection direction of the fuel injected from the injection hole 15 changes according to the lift amount of the valve body 2, in this fuel injection nozzle, the lift amount of the valve body 2 is small and low. The direction of fuel injection will change between the time of load and the time of high load when the lift amount of the valve body 2 is large.

Further, the valve body 2 is prevented from swinging by the annular protrusion 233. Therefore, the sizes of the gaps between the cover portion 24 and the inner peripheral surface of the blind hole 14 are always equal, and the amount of fuel injected from the injection hole 15 is the lift amount of the valve body 2. If it is constant, it does not vary from lift to lift and is always constant. Therefore, the combustion state can be further improved.

Further, in this embodiment, since the auxiliary fuel reservoir 18 is formed, the combustion state can be further improved. That is, the fuel flowing from the fuel introduction hole 13 toward the blind hole 14 passes through the passage 235. Here, since the passage 235 is not formed over the entire circumference of the fuel introduction hole 13 but is formed in a part of the circumference thereof, if the auxiliary fuel reservoir 18 is not formed, the blind hole 14 is formed. The pressure of the fuel that has flowed into the inside fluctuates in each part. Therefore, the injection amount from each injection hole 15 becomes non-uniform.

In this respect, in the fuel injection nozzle of this embodiment, the fuel that has passed through the passage 235 flows into the sub fuel reservoir 18. In this case, since the volume of the auxiliary fuel reservoir 18 is significantly larger than the inflow amount, the pressure in the auxiliary fuel reservoir 18 is maintained substantially uniform. Therefore, the fuel is uniformly injected from each injection hole 15.

Next, another embodiment of the present invention will be described. It is needless to say that the same effects as those of the above-described embodiments can be obtained in the embodiments described below. In the embodiment shown in FIG. 3, the opening inside the small hole 252 is arranged below the lower edge of the cover portion 24 of the valve body 2, and the small hole 252 is formed substantially horizontally.

In addition, in the embodiment shown in FIGS. 4 and 5, instead of forming the annular protruding portion 233 as a guide portion in the valve body 2, the upper shaft portion of the valve body 2 is provided at the lower end portion of the fuel introduction hole 13. 231 forms an annular protruding portion (guide portion) 131 which is slidably fitted, and the annular protruding portion 131 suppresses the vibration of the valve element 2. A notch 132 is formed in the annular protrusion 131 in order to connect the fuel introduction hole 13 and the auxiliary fuel reservoir 18 to each other.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and can be modified as appropriate without departing from the spirit of the invention. For example, in the above embodiment, a plurality of injection holes 15 are formed and the injection holes 15 are arranged point-symmetrically with respect to the axis L. However, the number of injection holes 15 formed is arbitrary, and with respect to the axis L. You may arrange | position asymmetrically. Further, although the small diameter portion 23 is composed of the upper shaft portion 231 and the lower shaft portion 232, it may have a uniform diameter as a whole like the conventional one. Further, the auxiliary fuel reservoir 18 does not necessarily have to be formed.

[0030]

[Effect of the device]

 As described above, according to the fuel injection nozzle of the present invention, the injection hole is formed by a plurality of small holes intersecting in the vicinity of the outer surface of the nozzle body, so that the fuel injection amount is changed according to the lift amount of the valve body. The injection direction can be changed. Therefore, the air in the entire combustion chamber can be efficiently used. Further, since the valve body is guided by the guide portion, it is possible to prevent the valve body from swinging, and the amount of fuel injected from the injection hole does not vary depending on the lift of the valve body, and the valve body does not vary. If the lift amount is constant, it can always be constant. In addition, it is possible to improve the combustion efficiency by improving the air utilization efficiency and keeping the fuel injection amount from the injection hole constant without varying for each lift of the valve element. Be done.

[Brief description of drawings]

1 shows an embodiment of the present invention, and FIG.
1A is a longitudinal sectional view thereof, and FIG. 1B is an enlarged view of a B circle portion of FIG. 1A.

FIG. 2 is an enlarged cross-sectional view taken along arrow XX in FIG.

FIG. 3 is a sectional view similar to FIG. 1B showing another embodiment of the present invention.

FIG. 4 is a vertical sectional view showing another embodiment of the present invention.

5 is an enlarged sectional view taken along the line YY of FIG.

FIG. 6 is a vertical cross-sectional view showing an example of a conventional fuel injection nozzle.

FIG. 7 is an enlarged view of a Z circle portion of FIG.

[Explanation of symbols]

 L axis 1 nozzle body 2 valve body 11 valve sliding hole 12 fuel reservoir 13 fuel introduction hole 14 blind hole 15 injection hole 17 valve seat 21 large diameter portion 23 small diameter portion 24 cover portion 25 valve portion 131 annular protrusion portion (guide portion) 151 Small hole 152 Small hole 233 Annular protrusion (guide)

Claims (1)

[Scope of utility model registration request] 1. A nozzle main body and a valve body slidably provided inside the nozzle main body, and the valve main body is provided inside the nozzle main body sequentially from one end side to the other end side on the axis thereof. A sliding hole, a fuel reservoir, a fuel introduction hole, a valve seat, and a tapered blind hole are formed, and one end opens on the inner peripheral surface of the blind hole and the other end opens on the outer surface. A large diameter portion slidably fitted in the valve sliding hole in order from one end side to the other end side, and a gap is formed in the fuel introduction hole through the fuel reservoir. Fuel having a small diameter portion inserted into the valve seat, a valve portion which is seated on the valve seat and blocks the blind hole from the fuel introduction hole, and a cover portion having a taper degree equal to or slightly smaller than the blind hole. In the injection nozzle, the injection hole is composed of a plurality of small holes. Two of the small holes are arranged such that the openings in the blind holes are separated from each other in the axial direction of the blind holes and the openings in the outer surface of the nozzle body intersect in the vicinity of the outer surface. A fuel is characterized in that at least one of the inner peripheral surface of the valve fuel introduction hole and the outer peripheral surface of the small diameter portion is formed with a guide portion for suppressing vibration in a direction orthogonal to the axis of the small diameter portion. Injection nozzle.