JP2001012334A - Fuel injection nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a uniform hollow-cone spray when an amount of lift of a needle valve, regardless of whether the needle valve is off-centered from a nozzle body or not. SOLUTION: A peripheral groove 4 is formed in the inner wall surface 3 of a nozzle body, and a nozzle hole entrance 5 is arranged in relation to the peripheral groove 4 so that the nozzle body rear end side part 6 relative to the nozzle hole entrance is overlapped with the nozzle body tip side part 8 of the peripheral groove, the nozzle body tip side part 7 relative to the nozzle hole entrance 5 is not overlapped with the peripheral groove 4, and the nozzle body rear end side part 9 relative to the peripheral groove is not overlapped with the nozzle hole entrance 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a fuel injection nozzle.

[0002]

2. Description of the Related Art Conventionally, there has been known a fuel injection nozzle having an injection hole communicating between the inside of the nozzle body and the outside of the nozzle body for injecting fuel to the outside of the nozzle body. An example of this type of fuel injection nozzle is disclosed in, for example,
There is one described in US Pat.

[0003]

SUMMARY OF THE INVENTION However, Japanese Patent Laid-Open No.
In the fuel injection nozzle described in Japanese Patent No. 67459, although a circumferential groove is formed on the inner wall surface of the nozzle body, and the rear end portion of the nozzle body at the nozzle hole overlaps with the circumferential groove, the tip of the nozzle body at the nozzle hole inlet. The side portion also overlaps with the circumferential groove, and the portion of the circumferential groove on the tip side of the nozzle body does not overlap with the injection hole inlet. In other words, in the fuel injection nozzle described in Japanese Patent Application Laid-Open No. 2-67459, the rear end portion of the nozzle body at the inlet of the injection hole overlaps with the front end portion of the nozzle body at the circumferential groove, and the front end portion of the nozzle body at the inlet of the injection hole. However, the injection hole inlet is not arranged with respect to the circumferential groove so that the nozzle does not overlap with the circumferential groove, and the portion of the circumferential groove on the rear end side of the nozzle body does not overlap with the injection hole inlet. Therefore, when the lift amount of the needle valve is small, uniform hollow cone spray cannot be formed regardless of whether the needle valve is eccentric with respect to the nozzle body or not. In addition, in this specification, the “rear end side of the nozzle body” refers to the side opposite to the nozzle body axial direction on the front end side of the nozzle body.

Another example of a fuel injection nozzle having an injection hole communicating between the inside of the nozzle body and the outside of the nozzle body for injecting fuel to the outside of the nozzle body is disclosed, for example, in Japanese Patent Laid-Open No. 4-86373. Some are described.

However, in the fuel injection nozzle described in Japanese Patent Application Laid-Open No. 4-86373, a recess is formed on the inner wall surface of the nozzle body, but no circumferential groove is formed on the inner wall surface of the nozzle body. That is, Japanese Patent Application Laid-Open No. 4-86373
In the fuel injection nozzle described in Japanese Patent Application Laid-Open Publication No. H11-157, a circumferential groove is formed on the inner wall surface of the nozzle body, and the rear end portion of the nozzle body at the inlet of the injection hole overlaps with the nozzle body front end portion of the circumferential groove. The nozzle hole inlet is not arranged in the circumferential groove so that the nozzle body front end portion does not overlap with the circumferential groove, and the nozzle body rear end portion of the circumferential groove does not overlap with the nozzle hole inlet. Therefore, when the lift amount of the needle valve is small, uniform hollow cone spray cannot be formed regardless of whether the needle valve is eccentric with respect to the nozzle body or not.

In view of the above problems, the present invention can form a uniform hollow cone spray when the lift of the needle valve is small, regardless of whether the needle valve is eccentric or not with respect to the nozzle body. It is an object of the present invention to provide a fuel injection nozzle in which an injection hole inlet is arranged with respect to a circumferential groove.

[0007]

According to the first aspect of the present invention, there is provided a fuel injection nozzle having an injection hole communicating between the inside of the nozzle body and the outside of the nozzle body for injecting fuel to the outside of the nozzle body. A peripheral groove is formed on the inner wall surface of the nozzle body, a rear end portion of the nozzle body at the inlet of the injection hole overlaps with a front end portion of the nozzle body of the peripheral groove, and a front end portion of the nozzle body at the inlet of the injection hole is formed with the peripheral groove. A fuel injection nozzle is provided in which the injection hole inlet is arranged with respect to the circumferential groove so that the nozzle groove rear end portion of the circumferential groove does not overlap with the injection hole inlet.

In the fuel injection nozzle according to the first aspect, a circumferential groove is formed in the inner wall surface of the nozzle body, and a rear end portion of the nozzle body at the inlet of the injection hole overlaps with a front end portion of the nozzle body in the circumferential groove. The injection hole inlet is arranged with respect to the circumferential groove such that the nozzle body front end portion of the injection hole does not overlap with the circumferential groove and the nozzle body rear end portion of the circumferential groove does not overlap with the injection hole inlet. When the lift amount of the needle valve is small, the space formed between the outer wall surface of the needle valve and the inner wall surface of the nozzle body is smaller than the space in the circumferential groove, and the fuel flowing into the circumferential groove is Since the fuel collides with the front end portion of the nozzle body, the fuel that has flowed into the circumferential groove forms a swirling flow in the circumferential groove. Since the state in which the central axis of this swirling flow is parallel to the tangential direction of the circumferential groove is very unstable, the direction of the central axis of the swirling flow is changed, and the swirling flow exists in the circumferential groove in a collapsed state. Can be When fuel flows into the injection hole while the swirl flow in the circumferential groove is collapsed, a swirl flow is also formed in the injection hole, and as a result, the needle valve is not eccentric with respect to the nozzle body. A uniform hollow cone spray is injected from the injection hole. On the other hand, when the needle valve is eccentric with respect to the nozzle body, although the swirling flow in the circumferential groove is weakened, the fuel flows from the nozzle body tip side portion of the injection hole inlet and the fuel in the injection hole is The swirling flow is strengthened, and as a result, a uniform hollow cone spray is injected from the injection hole as in the case where the needle valve is not eccentric with respect to the nozzle body. That is, when the lift amount of the needle valve is small, uniform hollow cone spray can be formed regardless of whether the needle valve is eccentric to the nozzle body or not. This phenomenon is caused by the fact that the space formed between the outer wall surface of the needle valve and the inner wall surface of the nozzle body is smaller than the space in the circumferential groove. Is not performed, and penetration injection is performed.

According to the second aspect of the present invention, a portion of the wall surface of the peripheral groove on the nozzle body front end side, which is in contact with the inner wall surface of the nozzle body, faces outward in the radial direction of the nozzle body. A fuel injection nozzle as defined in claim 1 is provided.

[0010] In the fuel injection nozzle according to the second aspect of the present invention, a portion of the peripheral groove, which is in contact with the inner wall surface of the nozzle body, is formed so as to face outward in the radial direction of the nozzle body. Therefore, the fuel that has flowed into the circumferential groove flows along the wall surface of the nozzle body at the tip end portion of the circumferential groove that faces outward in the radial direction of the nozzle body, and as a result, a swirling flow of the fuel in the circumferential groove is formed. Made easier.

According to the third aspect of the present invention, when a vertical cross section of the fuel injection nozzle is taken, a contour of a wall surface of a portion of the peripheral groove on a tip end side of the nozzle body draws a smooth concave curve. Item 1. A fuel injection nozzle according to item 1 is provided.

In the fuel injection nozzle according to the third aspect, when the vertical cross section of the fuel injection nozzle is taken, the contour of the wall surface of the peripheral groove at the tip end side of the nozzle body draws a smooth concave curve. The fuel that has flowed into the circumferential groove flows along the wall surface of the smoothly concaved circumferential groove at the tip end portion of the nozzle body, and as a result, a swirling flow of the fuel in the circumferential groove is easily formed.

According to the fourth aspect of the present invention, a tapered surface is formed between the wall surface of the peripheral groove on the rear end side of the nozzle body and the inner wall surface of the nozzle body located on the rear end side of the nozzle body. The angle formed between the tapered surface and the center axis of the fuel injection nozzle, the angle formed between the inner wall surface of the nozzle body and the center axis of the fuel injection nozzle, the wall surface of the peripheral groove at the rear end side of the nozzle body, and the fuel. By setting the value between the angle formed by the center axis of the injection nozzle and the angle formed by the central axis of the injection nozzle, the wall surface of the peripheral end of the nozzle body at the rear end side and the inner wall surface of the nozzle body located at the rear end side of the nozzle body can be smoothly continued. A fuel injection nozzle according to claim 1 is provided.

In the fuel injection nozzle according to the fourth aspect, the wall surface of the peripheral groove at the rear end side of the nozzle body and the inner wall surface of the nozzle body located at the rear end side of the nozzle body are smoothly connected by the tapered surface. Therefore, the fuel is easily flown into the circumferential groove, and as a result, a swirling flow of the fuel in the circumferential groove is easily formed.

According to the fifth aspect of the present invention, when the vertical cross section of the fuel injection nozzle is taken, the peripheral groove is located on the contour of the wall surface of the rear end side portion of the nozzle body and located on the rear end side of the nozzle body. The fuel injection nozzle according to claim 1, wherein the contour of the inner wall surface of the nozzle body is made continuous through a smooth convex curve.

In the fuel injection nozzle according to the fifth aspect, when the vertical cross section of the fuel injection nozzle is taken, the contour of the wall surface of the peripheral groove at the rear end side of the nozzle body and the nozzle body located at the rear end side of the nozzle body Since the contour of the inner wall surface is continued through a smooth convex curve, the fuel is easily flown into the circumferential groove, and as a result, the swirling flow of the fuel in the circumferential groove is easily formed.

According to the sixth aspect of the present invention, the needle valve is disposed inside the nozzle body, and the projection housed in the circumferential groove when the needle valve is located at the valve closing position is provided on the needle valve. A fuel injection nozzle according to claim 1 arranged is provided.

In the fuel injection nozzle according to the sixth aspect, the projection disposed on the needle valve is housed in the circumferential groove when the needle valve is located at the valve closing position. Therefore, the fuel passage volume on the downstream side of the valve seat portion is reduced as compared with the case where the projection is not arranged. As a result, the amount of fuel remaining in the fuel passage on the downstream side of the valve seat portion when the needle valve is closed is reduced. Therefore, the deterioration of HC emission due to the residual fuel being sucked out of the nozzle body by the negative pressure outside the nozzle body is reduced. Further, when the needle valve is opened, the protrusion facilitates the fuel to flow into the circumferential groove, and as a result, the swirling flow of the fuel in the circumferential groove is easily formed.

According to the seventh aspect of the present invention, when a vertical cross section of the fuel injection nozzle is taken, the contour of the wall surface of the projection on the nozzle tip side portion is drawn as a smooth concave curve. 2. A fuel injection nozzle according to (1) is provided.

In the fuel injection nozzle according to the seventh aspect, when the vertical cross section of the fuel injection nozzle is taken, the contour of the wall surface of the projection on the nozzle tip side is drawn as a smooth concave curve, so that the needle valve is provided. When the valve is opened, the protrusion makes it easier for the fuel to flow into the circumferential groove, and as a result, a swirling flow of the fuel in the circumferential groove is easily formed.

According to the present invention, the needle valve is arranged inside the nozzle body, and the lift amount of the needle valve is reduced when the engine is under a low load operation, and the lift amount of the needle valve is reduced when the engine is under a high load operation. Is increased.
2. A fuel injection nozzle according to (1) is provided.

In the fuel injection nozzle according to the eighth aspect, the lift amount of the needle valve is reduced during low engine load operation,
During the engine high load operation, the lift amount of the needle valve is increased. During engine low load operation with a small required fuel injection amount, the lift amount of the needle valve is reduced, and hollow cone spray, that is, diffusion spray is formed. Therefore, mixing of fuel and air is promoted, and combustion is improved. Further, since the injection flow rate becomes smaller than when the lift amount is large, the injection period can be set longer. On the other hand, at the time of engine high load operation, the lift amount of the needle valve is increased, and penetration injection is performed. Therefore, the fuel and the air are mixed by colliding the spray with the wall surface of the combustion chamber, and good combustion is ensured.

According to the ninth aspect of the present invention, the needle valve is disposed inside the nozzle body, the lift amount of the needle valve is reduced when the engine is running at a low speed, and the lift amount of the needle valve is increased when the engine is running at a high speed. A fuel injection nozzle according to claim 1 is provided.

In the fuel injection nozzle according to the ninth aspect, the lift of the needle valve is reduced when the engine is running at a low speed, and the lift of the needle valve is increased when the engine is running at a high speed. When the engine is running at a low engine speed where a long fuel injection period can be ensured, the lift amount of the needle valve is reduced, so that the fuel injection rate is reduced and diffusion spray is formed. Therefore, mixing of fuel and air is promoted, and combustion is improved. On the other hand, when the engine speed is high, in which the fuel injection period must be shortened, the penetration injection is performed by increasing the lift amount of the needle valve. Therefore, the fuel and the air are mixed by colliding the spray with the wall surface of the combustion chamber, and good combustion is ensured.

According to the tenth aspect of the present invention, the needle valve is disposed inside the nozzle body, the lift amount of the needle valve is reduced when pilot injection is to be performed, and the needle valve is not lifted when main injection is to be performed. The fuel injection nozzle according to claim 1, wherein the lift amount is increased.

In the fuel injection nozzle according to the tenth aspect,
When the pilot injection is to be performed, the lift amount of the needle valve is reduced, and when the main injection is to be performed, the lift amount of the needle valve is increased. By reducing the lift amount of the needle valve when pilot injection is to be performed, diffusion spray is formed during pilot injection. Therefore, bore flushing is prevented, and the effect of pilot injection can be reliably achieved.

According to the eleventh aspect of the present invention, the needle valve is disposed inside the nozzle body, the lift amount of the needle valve is reduced when post injection is to be performed, and the needle valve is not rotated when main injection is to be performed. The fuel injection nozzle according to claim 1, wherein the lift amount is increased.

[0028] In the fuel injection nozzle according to the eleventh aspect,
When the post injection is to be performed, the lift amount of the needle valve is reduced, and when the main injection is to be performed, the lift amount of the needle valve is increased. By reducing the lift amount of the needle valve when post injection is to be performed, diffusion spray is formed during post injection. Therefore, it is possible to supply unburned fuel into the exhaust passage while preventing bore flushing.

According to the twelfth aspect of the present invention, a fuel inflow passage is formed on the inner wall surface of the nozzle body on the rear end side of the nozzle body with respect to the peripheral groove, and the fuel inflow passage is located closest to the nozzle hole. 2. The fuel injection nozzle according to claim 1, wherein the fuel injection nozzle is circumferentially offset with respect to a central axis of the fuel injection nozzle.

[0030] In the fuel injection nozzle according to the twelfth aspect,
The fuel inflow passage formed on the inner wall surface of the nozzle body on the rear end side of the nozzle body with respect to the circumferential groove is circumferentially offset with respect to the center axis of the nearest injection hole. Therefore, the direction of the central axis of the swirl flow of the fuel formed in the circumferential groove is changed by the fuel flowing into the injection hole from the offset fuel inflow passage, and therefore, the swirl flow in the circumferential groove is changed. Is crushed. That is, the swirling flow of the fuel can be more positively formed in the injection hole than the fuel injection nozzle according to the first aspect. As a result, a hollow cone spray can be formed.

According to the thirteenth aspect of the present invention, a second peripheral groove is formed on a rear end side of the nozzle body with respect to the peripheral groove, and the peripheral groove and the second peripheral groove are formed in the fuel inflow passage. 13. The fuel injection nozzle according to claim 12, wherein the fuel injection nozzle is in communication with the fuel injection nozzle.

In the fuel injection nozzle according to the thirteenth aspect,
A second peripheral groove formed on the rear end side of the nozzle body with respect to the peripheral groove is connected to the peripheral groove by a fuel inflow path. Therefore, the flow of the fuel flowing into the injection hole from the offset fuel inflow path can be made stronger than that of the fuel injection nozzle according to the twelfth aspect.

According to the fourteenth aspect of the present invention, there is provided the fuel injection nozzle according to the thirteenth aspect, wherein the needle valve is disposed inside the nozzle body, and the second peripheral groove is formed in the needle valve. Is done.

[0034] In the fuel injection nozzle according to the fourteenth aspect,
A second circumferential groove is formed in the needle valve located inside the nozzle body. Therefore, the flow of the fuel flowing into the injection hole from the offset fuel inflow path can be made stronger than that of the fuel injection nozzle according to the twelfth aspect.

According to the fifteenth aspect of the invention, the fuel injection nozzle according to the twelfth aspect, wherein the fuel inflow passage is disposed on a central axis of the injection hole facing the central axis of the nozzle body. Is provided.

In the fuel injection nozzle according to the present invention,
The fuel inflow passage is disposed on the central axis of the injection hole facing the central axis of the nozzle body. for that reason,
The fuel inflow path and the injection hole can be machined by one machining tool. As a result, the processing of the fuel inflow path and the injection hole can be performed more easily than the case where the fuel inflow path and the injection hole are processed by separate processing tools.

According to the sixteenth aspect of the present invention, the injection hole and the fuel inflow path are formed by electric discharge machining so that the diameter of the fuel inflow path is larger than the diameter of the injection hole. 15. A fuel injection nozzle according to claim 15.

In the fuel injection nozzle according to the sixteenth aspect,
The injection hole and the fuel inflow path are formed by electric discharge machining so that the diameter of the fuel inflow path is larger than the diameter of the injection hole.
Because the injection hole and fuel inflow path are formed by electric discharge machining,
The processing of the fuel inflow path and the injection hole can be easily performed as compared with the case where the fuel inflow path and the injection hole are processed by separate processing tools. In addition, since the diameter of the fuel inflow passage is made larger than the diameter of the injection hole, the flow of fuel flowing from the offset fuel inflow passage into the injection hole is reduced by the diameter of the injection hole and the diameter of the fuel inflow passage. Can be stronger than if they are equal.

According to the seventeenth aspect of the present invention, in a fuel injection nozzle having an injection hole communicating between the inside of the nozzle body and the outside of the nozzle body for injecting fuel to the outside of the nozzle body, The groove is formed, and the nozzle body rear end portion of the injection hole inlet overlaps the nozzle body tip end portion of the groove, the nozzle body tip end portion of the injection hole inlet does not overlap with the groove, and the groove nozzle Disposing the injection hole inlet with respect to the groove so that the body rear end side portion does not overlap with the injection hole inlet, forming a fuel inflow passage on the inner wall surface of the nozzle body closer to the nozzle body rear end side than the groove; A fuel injection nozzle is provided wherein the fuel inflow passage is circumferentially offset with respect to the central axis of the nearest injection hole.

In the fuel injection nozzle according to the seventeenth aspect,
A groove is formed on the inner wall surface of the nozzle body, and the rear end portion of the nozzle body at the inlet of the nozzle hole overlaps the nozzle body front end portion of the groove, and the nozzle body front end portion of the nozzle hole does not overlap with the groove. Further, the injection hole inlet is arranged in the groove so that the nozzle body rear end side portion of the groove does not overlap with the injection hole inlet.
Therefore, when the lift amount of the needle valve is small, the space formed between the outer wall surface of the needle valve and the inner wall surface of the nozzle body becomes smaller than the space in the groove, and the fuel flowing into the groove is The fuel that has flowed into the groove forms a swirling flow in the groove because it collides with the front end portion of the nozzle body. Further, the fuel inflow passage formed on the inner wall surface of the nozzle body at the rear end side of the nozzle body with respect to the groove is circumferentially offset with respect to the center axis of the nearest injection hole.
Therefore, the direction of the central axis of the swirling flow of the fuel formed in the groove is changed by the fuel flowing into the injection hole from the offset fuel inflow passage, and therefore, the swirling flow in the groove is collapsed. It is in the state that was. When the fuel flows into the injection hole under a state where the swirl flow in the groove is crushed, a swirl flow is also formed in the injection hole, and as a result, when the needle valve is not eccentric with respect to the nozzle body, A uniform hollow cone spray is injected from the injection hole. On the other hand, when the needle valve is eccentric with respect to the nozzle body, the swirling flow in the groove is weakened, but the fuel swirls in the injection hole due to the fuel spilling from the nozzle body tip side portion at the injection hole inlet. The flow is intensified, and as a result, a uniform hollow cone spray is injected from the injection hole as in the case where the needle valve is not eccentric with respect to the nozzle body. That is,
When the lift amount of the needle valve is small, a uniform hollow cone spray can be formed regardless of whether the needle valve is eccentric with respect to the nozzle body.
This phenomenon is due to the fact that the space formed between the outer wall surface of the needle valve and the inner wall surface of the nozzle body is smaller than the space in the groove, so when the lift amount of the needle valve increases, hollow cone spray is formed. Disappears, and a penetration injection is performed.

[0041]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a partial sectional side view of a first embodiment of a fuel injection nozzle according to the present invention, FIG. 2 is an enlarged view of FIG. 1, and FIG. 3 is a peripheral groove of FIG. 2 viewed from the rear end side of the nozzle body. FIG. Specifically, FIGS. 2B and 3 show a swirl flow formed by the flow of fuel in the circumferential groove and the injection hole. 1 to 3
In the figure, 1 is a nozzle body, 2 is an injection hole communicating between the inside of the nozzle body 1 and the outside of the nozzle body 1 for injecting fuel to the outside of the nozzle body 1, and 3 is an inner wall surface of the nozzle body. 4 is a circumferential groove formed on the inner wall surface 3 of the nozzle body,
Reference numeral 5 denotes an injection hole inlet serving as an inlet portion of the injection hole 2, 6 denotes a nozzle body rear end portion of the injection hole inlet, and 7 denotes a nozzle body front end portion of the injection hole inlet. Reference numeral 8 denotes a portion of the circumferential groove on the front end of the nozzle body, 9 denotes a portion of the circumferential groove on the rear end of the nozzle body, and 10 denotes a needle valve. As shown in FIGS. 1 to 3, the injection hole inlet 5 of the fuel injection nozzle according to the present embodiment is configured such that the nozzle body rear end portion 6 of the injection hole inlet is a nozzle body front end portion 8 of a circumferential groove.
And the nozzle body front end portion 7 at the injection hole inlet does not overlap with the circumferential groove 4 and the nozzle body rear end portion 9 of the circumferential groove does not overlap.
Are arranged with respect to the circumferential groove 4 so as not to overlap with the injection hole inlet 5.

More specifically, as shown in FIGS. 2A and 2B, when the lift amount of the needle valve 10 is small, a space formed between the outer wall surface of the needle valve and the inner wall surface 3 of the nozzle body. Is smaller than the space in the circumferential groove 4, and the fuel flowing into the circumferential groove 4 collides with the nozzle body tip side portion 8 of the circumferential groove. A swirling flow is formed at. In detail, as shown in FIG. 3, since the state where the central axis L of the swirling flow is parallel to the tangential direction of the circumferential groove 4 is very unstable, the direction of the central axis L of the swirling flow is changed, The swirling flow is present in the circumferential groove in a collapsed state. 2 (b) and 3
As shown in FIG. 2, when the fuel flows into the injection hole 2 under the condition that the swirl flow in the circumferential groove 4 is crushed, a swirl flow is also formed in the injection hole 2, and as a result, the nozzle body 1
When the needle valve 10 is not eccentric with respect to the center axis of the nozzle, uniform hollow cone spray is injected from the injection hole 2.
On the other hand, the needle valve 10
Is eccentric, the swirl flow in the circumferential groove 4 is weakened, but the fuel swirls in the injection hole 2 as the fuel flows from the nozzle body tip side portion 7 at the injection hole inlet. As a result, as in the case where the needle valve 10 is not eccentric with respect to the central axis of the nozzle body 1, uniform hollow cone spray is injected from the injection hole 2.

That is, according to the present embodiment, the needle valve 1
When the lift amount of zero is small, a uniform hollow cone spray can be formed regardless of whether the needle valve 10 is eccentric with respect to the nozzle body 1 or not.
This phenomenon is caused by the fact that the space formed between the outer wall surface of the needle valve 10 and the inner wall surface 3 of the nozzle body is smaller than the space in the circumferential groove. Spray no longer forms,
Penetration injection is performed from the injection hole 2.

FIG. 4 is an enlarged view similar to FIG. 2 of a second embodiment of the fuel injection nozzle of the present invention. See Figure 4 for details
(B) shows a swirling flow formed by the fuel flow in the circumferential groove and the injection hole. In FIG. 4, the same reference numbers as those shown in FIGS. 1 to 3 indicate the same parts or parts as those shown in FIGS.
Reference numeral 1 denotes a nozzle body, 102 denotes an injection hole communicating between the inside of the nozzle body 101 and the outside of the nozzle body 101 for injecting fuel to the outside of the nozzle body 101, and 103 denotes an inner wall surface of the nozzle body. 104 is a nozzle body inner wall surface 103
The reference numeral 105 denotes an injection hole inlet which is an inlet portion of the injection hole 102, 106 denotes a nozzle body rear end portion of the injection hole inlet, and 107 denotes a nozzle body tip end portion of the injection hole inlet. 108 is the peripheral groove side of the nozzle body at the tip end;
Reference numeral 9 denotes a portion of the peripheral groove on the rear end side of the nozzle body. As shown in FIG. 4, in the fuel injection nozzle of the present embodiment, a portion of the peripheral groove, which is in contact with the inner wall surface 103 of the nozzle body, of the nozzle body front end portion 108 is the nozzle body 101.
Are formed so as to face outward in the radial direction.

According to the present embodiment, the inner wall surface 1 of the nozzle body, out of the wall surfaces of the nozzle body tip side portion 108 of the peripheral groove, is formed.
The fuel that has flowed into the circumferential groove 104 is moved along the wall surface of the nozzle body front end portion 108 of the circumferential groove facing the radial outside of the nozzle body 101 by the portion in contact with 03. As a result, a swirling flow of the fuel in the circumferential groove 104 is more easily formed than in the first embodiment.

FIG. 5 is an enlarged view similar to FIG. 2 of the third embodiment of the fuel injection nozzle of the present invention. See Figure 5 for details
(B) shows a swirling flow formed by the fuel flow in the circumferential groove and the injection hole. In FIG. 5, the same reference numbers as those shown in FIGS. 1 to 4 indicate the same parts or parts as those shown in FIGS.
Reference numeral 1 denotes a nozzle body, 202 denotes an injection hole communicating between the inside of the nozzle body 201 and the outside of the nozzle body 201 for injecting fuel to the outside of the nozzle body 201, and 203 denotes an inner wall surface of the nozzle body. 204 is the inner wall surface of the nozzle body 203
The reference numeral 205 denotes an injection hole inlet which is an inlet portion of the injection hole 202, 206 denotes a nozzle body rear end portion of the injection hole inlet, and 207 denotes a nozzle body tip end portion of the injection hole inlet. 208 is a portion of the circumferential groove on the tip side of the nozzle body, 20
Reference numeral 9 denotes a portion of the peripheral groove on the rear end side of the nozzle body. As shown in FIG. 5, in the fuel injection nozzle of this embodiment, when the vertical cross section of the fuel injection nozzle is taken as shown in FIG. 5, the contour of the wall surface of the nozzle body tip side portion 208 of the circumferential groove is a smooth concave curve. To be drawn.

According to the present embodiment, the fuel flowing into the circumferential groove 204 is allowed to flow into the smoothly grooved nozzle body by the wall surface of the nozzle body tip side portion 208 of the circumferential groove which forms a smooth concave shape. It is moved along the wall surface of the distal end portion 208. As a result, the swirling flow of the fuel in the circumferential groove 204 is more easily formed than in the first embodiment.

FIG. 6 is an enlarged view similar to FIG. 2 of a fourth embodiment of the fuel injection nozzle of the present invention. See Figure 6 for details
(B) shows a swirling flow formed by the fuel flow in the circumferential groove and the injection hole. In FIG. 6, the same reference numerals as those shown in FIGS. 1 to 5 indicate the same parts or parts as those shown in FIGS.
Reference numeral 1 denotes a nozzle body, 302 denotes an injection hole communicating between the inside of the nozzle body 301 and the outside of the nozzle body 301 for injecting fuel to the outside of the nozzle body 301, and 303 denotes an inner wall surface of the nozzle body. 304 is the inner wall surface of the nozzle body 303
305 is an injection hole inlet which is an inlet portion of the injection hole 302, 306 is a nozzle body rear end portion of the injection hole inlet, and 307 is a nozzle body front end portion of the injection hole inlet. 308 is a portion of the circumferential groove on the tip side of the nozzle body, 30
9 is a tapered portion formed between the wall surface of the nozzle body rear end portion 309 of the peripheral groove and the nozzle body inner wall surface 303 located at the nozzle body rear end side. Plane.

As shown in FIG. 6, in the fuel injection nozzle of this embodiment, the angle formed by the tapered surface 311 and the center axis of the nozzle body is equal to the angle formed by the inner wall surface 303 of the nozzle body and the center axis of the nozzle body. The angle between the wall surface of the nozzle body rear end portion 309 of the circumferential groove and the central axis of the nozzle body is set to a value between the wall surface of the nozzle body rear end portion 309 of the circumferential groove and the nozzle body rear end side. The located nozzle body inner wall surface 303 is smoothly continued.

According to the present embodiment, since the tapered surface 311 as described above is formed, the fuel is transferred to the circumferential groove 30.
4 is made easier to flow into. As a result, a swirling flow of the fuel in the circumferential groove 304 is more easily formed than in the first embodiment.

FIG. 7 is an enlarged view similar to FIG. 2 of the fifth embodiment of the fuel injection nozzle of the present invention. See Figure 7 for details
(B) shows a swirling flow formed by the fuel flow in the circumferential groove and the injection hole. In FIG. 7, the same reference numerals as those shown in FIGS. 1 to 6 indicate the same parts or parts as those shown in FIGS.
Reference numeral 1 denotes a nozzle body; 402, an injection hole communicating between the inside of the nozzle body 401 and the outside of the nozzle body 401 for injecting fuel to the outside of the nozzle body 401; 404 is the inner wall surface 403 of the nozzle body
405 is an injection hole inlet which is an inlet portion of the injection hole 402, 406 is a nozzle body rear end portion of the injection hole inlet, and 407 is a nozzle body front end portion of the injection hole inlet. 408 is a portion of the circumferential groove on the tip side of the nozzle body;
Reference numeral 9 denotes a rear end portion of the peripheral groove of the nozzle body, and reference numeral 412 denotes a continuous portion that connects the rear end portion of the peripheral groove with the nozzle body inner wall surface located at the rear end side of the nozzle body. As shown in FIG. 7, in the fuel injection nozzle of the present embodiment, when a vertical cross section of the fuel injection nozzle is taken as shown in FIG.
The contour of the wall surface of the nozzle body rear end side portion 409 of the circumferential groove and the nozzle body inner wall surface 4 located on the nozzle body rear end side
The contour of 03 is continued through the smooth convex curve of the continuous portion 412.

According to the present embodiment, the contour of the wall surface of the nozzle body rear end side portion 409 of the circumferential groove and the contour of the nozzle body inner wall surface 403 located on the nozzle body rear end side are smooth convex portions of the continuous portion 412. The fuel is made to flow continuously through the shape curve, so that the fuel easily flows into the circumferential groove 404. As a result, a swirling flow of the fuel in the circumferential groove 404 is more easily formed than in the first embodiment.

FIG. 8 is an enlarged view similar to FIG. 2 of the sixth embodiment of the fuel injection nozzle of the present invention. See Figure 8 for details
(B) shows a swirling flow formed by the fuel flow in the circumferential groove and the injection hole. 8, the same reference numerals as those shown in FIGS. 1 to 7 denote the same parts or parts as those shown in FIGS.
Numeral 0 is a needle valve, and 513 is a projection arranged so as to be accommodated in the circumferential groove 4 when the needle valve 510 is located at the valve closing position.

According to the present embodiment, since the projection 513 is arranged in the circumferential groove 4 when the needle valve 510 is at the valve closing position as described above, the first embodiment in which the projection is not arranged is used. In comparison, a valve seat portion (not shown; FIG. 8)
(A). ), The volume of fuel remaining on the downstream side of the valve seat portion when the needle valve 510 is closed is reduced. Therefore, deterioration of HC emission due to the residual fuel being sucked out of the nozzle body by the negative pressure outside the nozzle body is reduced. More specifically, as shown in FIG. 8B, when the needle valve 510 is opened, the protrusion 513 makes it easier for the fuel to flow into the circumferential groove 4. As a result, a swirling flow of the fuel in the circumferential groove 4 is more easily formed than in the first embodiment.

FIG. 9 is an enlarged view similar to FIG. 2 of the seventh embodiment of the fuel injection nozzle of the present invention. See Figure 9 for details.
(B) shows a swirling flow formed by the fuel flow in the circumferential groove and the injection hole. In FIG. 9, the same reference numerals as those shown in FIGS. 1 to 8 indicate the same parts or parts as those shown in FIGS.
Reference numeral 0 denotes a needle valve, 613 denotes a projection arranged so as to be accommodated in the circumferential groove 4 when the needle valve 610 is located at the valve closing position, and 614 denotes a nozzle tip side portion of the projection. As shown in FIG. 9, in the fuel injection nozzle of the present embodiment, when the vertical cross section of the fuel injection nozzle is taken as shown in FIG. 9, the contour of the wall surface of the nozzle tip side portion 614 of the projection draws a smooth concave curve. Thus, the nozzle tip side portion 614 of the projection is formed.

According to this embodiment, since the contour of the wall surface of the nozzle tip side portion 614 of the projection is drawn in a smooth concave curve as described above, when the needle valve 610 is opened (FIG. 9B In addition, due to the nozzle tip side portion 614 of the projection, the fuel can flow into the circumferential groove 4 more easily than in the sixth embodiment. As a result, a swirling flow of the fuel in the circumferential groove 4 is more easily formed than in the case of the sixth embodiment.

FIG. 10 is a partial cross-sectional side view similar to FIG. 1 of the eighth embodiment of the fuel injection nozzle of the present invention, and FIG. 11 is a view showing the spray injected from the fuel injection nozzle. 10A shows the fuel injection nozzle when the lift amount of the needle valve is small, and FIG. 11A shows the spray when the lift amount of the needle valve is small.
11B shows the fuel injection nozzle when the lift amount of the needle valve is large, and FIG. 11B shows the spray when the lift amount of the needle valve is large. 10, the same reference numerals as those shown in FIG. 1 indicate the same parts or portions as those shown in FIG.
, 700 is hollow cone spraying, 701 is spraying by penetration injection, 750 is a fuel injection nozzle, 751 is a piston, and 752 is a combustion chamber.

In this embodiment, FIGS. 10 (a) and 11
As shown in (a), during low engine load operation where the required fuel injection amount is small, the lift amount of the needle valve 10 is reduced,
Hollow cone spray 700, a diffusion spray, is formed. Therefore, mixing of fuel and air is promoted, and combustion is improved. Further, since the injection flow rate becomes smaller than when the lift amount is large, the injection period can be set longer. On the other hand, as shown in FIGS. 10 (b) and 11 (b), at the time of engine high load operation, the lift amount of the needle valve 10 is increased, penetration injection is performed, and spray 7 by penetration injection is performed.
01 is formed. Therefore, the spray 701 is supplied to the combustion chamber 75.
By colliding with the two wall surfaces, mixing of fuel and air is achieved, and good combustion is ensured.

Hereinafter, a ninth embodiment of the fuel injection nozzle of the present invention will be described. The fuel injection nozzle of this embodiment is almost the same as that of the eighth embodiment shown in FIG. 10, and the spray of this embodiment is almost the same as that of the eighth embodiment shown in FIG. In the present embodiment, FIG.
As shown in FIG. 11A and FIG. 11A, when the engine is running at a low speed where a long fuel injection period can be ensured, the lift amount of the needle valve 10 is reduced, so that the fuel injection rate is reduced and the hollow cone spraying is performed. 700 is formed.
Therefore, mixing of fuel and air is promoted, and combustion is improved. On the other hand, as shown in FIG. 10 (b) and FIG. 11 (b), at the time of high engine rotation in which the fuel injection period has to be shortened, the penetrating injection is performed by increasing the lift amount of the needle valve 10, A spray 701 is formed by the penetration injection. Therefore, the spray 701 is supplied to the combustion chamber 7
By colliding with the 52 wall, fuel and air are mixed, and good combustion is ensured.

Hereinafter, a tenth embodiment of the fuel injection nozzle of the present invention will be described. The fuel injection nozzle of this embodiment is almost the same as that of the eighth embodiment shown in FIG. 10, and the spray of this embodiment is almost the same as that of the eighth embodiment shown in FIG. In the present embodiment, FIG.
As shown in FIG. 11A and FIG. 11A, when the pilot injection is to be performed, the hollow cone spray 700 is formed by reducing the lift amount of the needle valve 10. Therefore, bore flushing is prevented, and the effect of pilot injection can be reliably achieved. on the other hand,
When the main injection is to be performed as shown in FIGS. 10B and 11B, the lift amount of the needle valve 10 is increased.

Hereinafter, an eleventh embodiment of the fuel injection nozzle of the present invention will be described. The fuel injection nozzle of this embodiment is almost the same as that of the eighth embodiment shown in FIG. 10, and the spray of this embodiment is almost the same as that of the eighth embodiment shown in FIG. In the present embodiment, FIG.
As shown in FIG. 11A and FIG. 11A, when the post injection is to be performed, the hollow cone spray 700 is formed by reducing the lift amount of the needle valve 10. Therefore, it is possible to supply unburned fuel into the exhaust passage while preventing bore flushing. On the other hand, FIG.
When the main injection is to be performed as shown in FIG. 11B and FIG. 11B, the lift amount of the needle valve 10 is increased.

Hereinafter, a twelfth embodiment of the fuel injection nozzle of the present invention will be described. The fuel injection nozzle of this embodiment is almost the same as that of the eighth embodiment shown in FIG. 10, and the spray by the penetration injection of this embodiment is shown in FIG.
Is substantially the same as that of the eighth embodiment shown in FIG. FIG.
FIG. 2 is a diagram showing the hollow cone spray of the present embodiment and the timing at which it is sprayed. In the present embodiment, FIG.
As shown in FIG. 0 (a) and FIG. 12, in a low-load low-speed operation region where homogeneous premix combustion is possible, the lift amount of the needle valve 10 is reduced, and fuel injection is performed at an early stage before the air-fuel mixture is compressed. Done. On the other hand, FIG.
As shown in (b), in the high-load and high-speed operation region where the homogeneous premixed combustion is not established, the lift amount of the needle valve 10 is increased, and normal injection is performed near the compression top dead center.

FIG. 13 shows a thirteenth embodiment of the fuel injection nozzle according to the present invention.
It is a figure showing an embodiment. In detail, FIG.
FIG. 13 is a partial cross-sectional side view similar to FIG.
(B) is a view of the inner wall surface 3 of the nozzle body viewed from the rear end side of the nozzle body. In FIG. 13, the same reference numerals as those shown in FIGS. 1 to 12 indicate the same parts or parts as those shown in FIGS.
Reference numeral 1 denotes a nozzle body, and 816 denotes a fuel inflow passage formed on the inner wall surface 3 of the nozzle body on the rear end side of the nozzle body with respect to the circumferential groove 4. As shown in FIG. 13 and in detail, FIG.
The fuel inflow passage 816 is located closest, that is, offset in the circumferential direction with respect to the center axes L <b> 1 to L <b> 6 of the adjacent injection holes 2. Also preferably, the fuel inflow passage 816
Are arranged on the central axes L1 to L6 of the injection holes facing each other across the central axis O of the nozzle body.

According to the present embodiment, the fuel inflow passage 816 formed on the inner wall surface 3 of the nozzle body at the rear end side of the nozzle body with respect to the circumferential groove 4 is arranged so that the center axis L1 to L6 Are offset in the circumferential direction. Therefore, the direction of the center axis L (see FIG. 3) of the swirling flow of the fuel formed in the circumferential groove 4 is directed from the fuel inflow passage 816 offset with respect to the center axis of the injection hole 2 into the injection hole 2. The swirling flow in the circumferential groove 4 is changed by the inflowing fuel, so that it is collapsed as shown in FIG. That is, a swirling flow that is more positively collapsed than the fuel injection nozzle of the first embodiment can be formed in the circumferential groove 4, and a swirling flow can be formed in the injection hole 2. As a result, a hollow cone spray can be formed.

FIG. 14 shows a fourteenth embodiment of the fuel injection nozzle of the present invention.
It is a figure showing an embodiment. In detail, FIG.
Is a partial cross-sectional side view similar to FIG.
FIG. 14B is a view similar to FIG. 13B in which the inner wall surface 3 of the nozzle body is viewed from the rear end side of the nozzle body. 14, the same reference numerals as those shown in FIGS. 1 to 13 indicate the same parts or parts as those shown in FIGS. 1 to 13, and reference numeral 901 denotes a nozzle body;
Is a second peripheral groove formed on the inner wall surface 3 of the nozzle body on the rear end side of the nozzle body with respect to the peripheral groove 4. As shown in FIG. 14, the circumferential groove 4 and the second circumferential groove 917 are connected by a fuel inflow path 816.

According to the present embodiment, the second circumferential groove 917 formed on the rear end side of the nozzle body with respect to the circumferential groove 4 and the circumferential groove 4 are communicated with each other by the fuel inflow path 816. for that reason,
The flow of the fuel flowing into the injection hole 2 from the fuel inflow passage 816 offset with respect to the injection hole 2 can be made stronger than the fuel injection nozzle of the thirteenth embodiment. As a result, a swirling flow stronger than the fuel injection nozzle of the thirteenth embodiment can be formed in the injection hole 2.

FIG. 15 shows a fifteenth embodiment of the fuel injection nozzle according to the present invention.
It is a figure showing an embodiment. More specifically, FIG. 15 is a partial cross-sectional side view similar to FIG. 14A of the present embodiment.
In FIG. 15, the same reference numerals as those shown in FIGS. 1 to 14 indicate the same parts or parts as those shown in FIGS. 1 to 14, 1010 is a needle valve, and 1018 is This is a second peripheral groove formed on the outer wall surface of the needle valve 1010 on the rear end side of the nozzle body with respect to the peripheral groove 4. As shown in FIG. 15, the circumferential groove 4 and the second circumferential groove 1018
Are communicated with each other by a fuel inflow passage 816.

According to the present embodiment, substantially the same effects as in the fourteenth embodiment can be obtained. Further, since the second peripheral groove 1018 is formed not on the inner wall surface of the nozzle body 801 but on the outer wall surface of the needle valve 1010,
The processing of the second circumferential groove can be performed more easily than the fuel injection nozzle of the embodiment.

FIG. 16 shows a sixteenth embodiment of the fuel injection nozzle of the present invention.
It is a figure showing an embodiment. In detail, FIG.
Is a partial cross-sectional side view similar to FIG.
FIG. 16B is a view similar to FIG. 13B in which the inner wall surface 3 of the nozzle body is viewed from the rear end side of the nozzle body. 16, the same reference numerals as those shown in FIGS. 1 to 15 indicate the same parts or parts as those shown in FIGS. 1 to 15, 1101 is a nozzle body, 11
Reference numeral 02 denotes an injection hole communicating between the inside of the nozzle body 1101 and the outside of the nozzle body 1101 for injecting fuel to the outside of the nozzle body 1101, and 1116 is formed on the inner wall surface 3 of the nozzle body closer to the rear end side of the nozzle body than the circumferential groove 4. This is the fuel inflow path. As shown in FIG. 16, specifically, FIG. 16B, the fuel inflow passage 1116 is the first fuel inflow passage shown in FIG.
As in the third embodiment, the nozzle holes 1102 are arranged on the central axis of the injection hole 1102 facing the nozzle body with respect to the central axis O. That is, the fuel inflow path 1116a is
02a by the same tool as the tool for machining the nozzle hole 110a.
It is processed simultaneously with processing 2a. Similarly, the fuel inflow passages 1116b to 1116f are provided at the injection holes 1102b to 1102b.
02f, the injection hole 110
It is processed at the same time as 2b to 1102f.

According to the present embodiment, the fuel inflow passage 1116
Are arranged on the center axis of the injection hole 1102 facing the nozzle body center axis O. for that reason,
The fuel inflow passage 1116 and the injection hole 1102 can be machined by one machining tool. As a result, the fuel inflow path 11
The processing of the fuel inflow path 1116 and the injection hole 1102 can be performed more easily than the case where the injection hole 1102 and the injection hole 1102 are processed by separate processing tools.

FIG. 17 shows a seventeenth embodiment of the fuel injection nozzle of the present invention.
It is a figure showing an embodiment. Specifically, FIG. 17 is a partial cross-sectional side view similar to FIG. 13A of the present embodiment.
17, the same reference numerals as those shown in FIGS. 1 to 16 indicate the same parts or parts as those shown in FIGS. 1 to 16, 1201 is a nozzle body, 1202 is In order to inject fuel to the outside of the nozzle body 1201, the inside of the nozzle body 1201 and the nozzle body 1
An injection hole 1216 communicating with the outside of the nozzle 201 is a fuel inflow passage formed in the inner wall surface 3 of the nozzle body on the rear end side of the nozzle body with respect to the peripheral groove 4. As shown in FIG.
2 and the fuel inflow path 1216 are formed by electric discharge machining so that the diameter D2 of the fuel inflow path 1216 is larger than the diameter D1 of the injection hole. That is, the tool is swung about the injection hole outlet (the opposite side of the injection hole entrance 5), and the injection hole 1202
And a fuel inflow passage 1216.

According to the present embodiment, since the injection hole 1202 and the fuel inflow passage 1216 are formed by electric discharge machining, the fuel inflow passage 1216 and the fuel inflow passage 1216 are formed in comparison with the case where the fuel inflow passage and the injection hole are machined by separate machining tools. In addition, the processing of the injection hole 1202 can be easily performed. In addition, since the diameter D2 of the fuel inflow passage 1216 is larger than the diameter D1 of the injection hole 1202, the flow of fuel flowing into the injection hole 1202 from the fuel inflow passage 1216 offset from the center axis of the injection hole 1202. Can be made stronger than when the diameter of the injection hole is equal to the diameter of the fuel inflow passage.

FIG. 18 shows an eighteenth fuel injection nozzle according to the present invention.
It is a figure showing an embodiment. In detail, FIG.
FIG. 18 is a partial cross-sectional side view similar to FIG.
(B) is a view of the inner wall surface 3 of the nozzle body viewed from the rear end side of the nozzle body. In FIG. 18, the same reference numbers as those shown in FIGS. 1 to 17 indicate the same parts or parts as those shown in FIGS.
01 is the nozzle body, 1304 is the inner wall surface of the nozzle body 3
The groove is formed in the groove. 18 (a) and 18 (b)
As shown in the figure, the nozzle body rear end portion of the injection hole inlet 5 overlaps with the nozzle body front end portion of the groove 1304, the nozzle body front end portion of the injection hole inlet 5 does not overlap with the groove 1304, and In order to prevent the rear end portion of the nozzle body 1304 from overlapping with the nozzle hole inlet 5, the nozzle hole 5
Is arranged. Further, a fuel inflow passage 816 is formed on the inner wall surface 3 of the nozzle body closer to the rear end of the nozzle body than the groove 1304, and the fuel inflow passage 816 is located closest to the nozzle body.
That is, it is offset in the circumferential direction with respect to the center axes L1 to L6 of the adjacent injection holes 2.

According to the present embodiment, when the lift amount of the needle valve 10 is small, the space formed between the outer wall surface of the needle valve 10 and the inner wall surface 3 of the nozzle body becomes smaller than the space in the groove 1304, Further, since the fuel flowing into the groove 1304 collides with the nozzle body front end portion of the groove 1304, that is, the nozzle body front end portion of the injection hole inlet 5, the fuel flowing into the groove 1304 generates a swirling flow in the groove. (See FIG. 2B). Further, the fuel inflow passage 816 formed on the inner wall surface 3 of the nozzle body on the rear end side of the nozzle body with respect to the groove 1304 is circumferentially offset with respect to the central axis of the injection hole 2 located closest to the groove. The direction of the central axis L (see FIG. 3) of the swirling flow of the fuel formed in 1304 is determined by the fuel flowing into the injection hole 2 from the fuel inflow passage 816 offset with respect to the central axis of the injection hole 2. It is changed and therefore the swirling flow in the groove is collapsed (see FIG. 3). Groove 1304
When the fuel flows into the injection hole 2 in a state where the swirl flow in the inside is collapsed, a swirl flow is also formed in the injection hole 2, and as a result, the needle valve 10 is eccentric with respect to the nozzle body 1301. If not, a uniform hollow cone spray is injected from the injection hole 2. On the other hand, the nozzle body 1301
When the needle valve 10 is eccentric, the swirling flow in the groove 4 is weakened, but the fuel swirls in the injection hole 2 as the fuel flows from the nozzle body tip side portion of the injection hole inlet 5. The flow is strengthened and as a result, the nozzle body 1
As with the case where the needle valve 10 is not eccentric with respect to 301, uniform hollow cone spray is injected from the injection hole 2.
That is, when the lift amount of the needle valve 10 is small, uniform hollow cone spray can be formed regardless of whether the needle valve 10 is eccentric with respect to the nozzle body 1301 or not. This phenomenon is caused by the fact that the space formed between the outer wall surface of the needle valve 10 and the inner wall surface 3 of the nozzle body is smaller than the space in the groove 1304. Spray is no longer formed and penetrating injection is performed.

[0076]

According to the first aspect of the present invention, when the lift amount of the needle valve is small, a uniform hollow cone spray is formed regardless of whether or not the needle valve is eccentric with respect to the nozzle body. be able to.

According to the second aspect of the present invention, the fuel that has flowed into the circumferential groove flows along the wall surface of the nozzle body tip side portion of the circumferential groove that faces outward in the radial direction of the nozzle body. It is possible to easily form a swirling flow of the fuel in the circumferential groove for forming the hollow cone spray.

According to the third aspect of the present invention, the fuel that has flowed into the circumferential groove flows along the wall surface at the nozzle body tip side portion of the smooth concavely formed circumferential groove, and as a result, the hollow cone spray is formed. Can be easily formed in the swirl flow of the fuel in the circumferential groove for forming the fuel flow.

According to the fourth aspect of the present invention, the fuel is easily flown into the circumferential groove by the tapered surface. As a result, the formation of the swirling flow of the fuel in the circumferential groove for forming the hollow cone spray is performed. Can be easier.

According to the fifth aspect of the invention, the fuel is easily flowed into the circumferential groove by the convex portion, and as a result, the formation of the swirling flow of the fuel in the circumferential groove for forming the hollow cone spray is performed. Can be easier.

According to the sixth aspect of the present invention, the fuel passage volume on the downstream side of the valve seat portion is reduced as compared with the case where the projection is not arranged, and the fuel on the downstream side of the valve seat portion is closed when the needle valve is closed. The amount of fuel remaining in the passage is reduced, and therefore, the HC associated with the residual fuel being drawn out of the nozzle body by the negative pressure outside the nozzle body
Emission deterioration can be reduced. Further, when the needle valve is opened, the protrusion facilitates the fuel to flow into the circumferential groove, and as a result, it is possible to easily form a swirling flow of the fuel in the circumferential groove for forming the hollow cone spray. .

According to the seventh aspect of the present invention, when the needle valve is opened, the fuel is more easily flowed into the circumferential groove due to the concave portion on the nozzle tip side portion of the projection. It is possible to easily form a swirling flow of the fuel in the circumferential groove to be formed.

According to the present invention, mixing of fuel and air can be promoted during both low engine load operation and high engine load operation, and combustion can be improved.

According to the ninth aspect of the present invention, mixing of fuel and air can be promoted at both low engine speed and high engine speed to improve combustion.

According to the tenth aspect, an appropriate injection can be executed both when the pilot injection is to be performed and when the main injection is to be performed.

According to the eleventh aspect, appropriate injection can be performed both when post-injection is to be performed and when main injection is to be performed.

According to the twelfth aspect of the present invention, a swirling flow of fuel can be formed in the injection hole more positively than the fuel injection nozzle of the first aspect.

According to the thirteenth aspect, the flow of fuel flowing into the injection hole from the offset fuel inflow path can be made stronger than that of the fuel injection nozzle according to the twelfth aspect.

According to the fourteenth aspect of the present invention, the flow of fuel flowing into the injection hole from the offset fuel inflow path can be made stronger than that of the fuel injection nozzle according to the twelfth aspect.

According to the fifteenth aspect, the fuel inflow path and the injection hole can be easily processed as compared with the case where the fuel inflow path and the injection hole are processed by separate processing tools.

According to the sixteenth aspect of the present invention, the processing of the fuel inflow path and the injection hole can be easily performed as compared with the case where the fuel inflow path and the injection hole are processed by separate processing tools. In addition, the flow of fuel flowing into the injection hole from the offset fuel inflow passage can be made stronger than when the diameter of the injection hole is equal to the diameter of the fuel inflow passage.

According to the seventeenth aspect, when the lift amount of the needle valve is small, it is possible to form a uniform hollow cone spray regardless of whether the needle valve is eccentric with respect to the nozzle body or not. it can.

[Brief description of the drawings]

FIG. 1 is a partial sectional side view of a first embodiment of a fuel injection nozzle of the present invention.

FIG. 2 is an enlarged view of FIG.

FIG. 3 is a view of the circumferential groove of FIG. 2 viewed from a rear end side of a nozzle body.

FIG. 4 is an enlarged view similar to FIG. 2 of a second embodiment of the fuel injection nozzle of the present invention.

FIG. 5 is an enlarged view similar to FIG. 2 of a third embodiment of the fuel injection nozzle of the present invention.

FIG. 6 is an enlarged view similar to FIG. 2 of a fourth embodiment of the fuel injection nozzle of the present invention.

FIG. 7 is an enlarged view similar to FIG. 2 of a fifth embodiment of the fuel injection nozzle of the present invention.

FIG. 8 is an enlarged view similar to FIG. 2 of a sixth embodiment of the fuel injection nozzle of the present invention.

FIG. 9 is an enlarged view similar to FIG. 2 of a seventh embodiment of the fuel injection nozzle of the present invention.

FIG. 10 is a partial cross-sectional side view similar to FIG. 1 of an eighth embodiment of the fuel injection nozzle of the present invention.

FIG. 11 is a diagram showing a spray injected from a fuel injection nozzle.

FIG. 12 is a diagram showing the hollow cone spray of this embodiment and the timing at which it is sprayed.

FIG. 13 is a view showing a thirteenth embodiment of a fuel injection nozzle according to the present invention.

FIG. 14 is a view showing a fuel injection nozzle according to a fourteenth embodiment of the present invention.

FIG. 15 is a view showing a fuel injection nozzle according to a fifteenth embodiment of the present invention.

FIG. 16 is a view showing a fuel injection nozzle according to a sixteenth embodiment of the present invention.

FIG. 17 is a view showing a fuel injection nozzle according to a seventeenth embodiment of the present invention.

FIG. 18 is a view showing an eighteenth embodiment of the fuel injection nozzle of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Nozzle body 2 ... Injection hole 3 ... Nozzle body inner wall surface 4 ... Peripheral groove 5 ... Injection hole entrance 6 ... Nozzle body rear end portion of injection hole entrance 7 ... Nozzle body front end portion of injection hole entrance 8 ... Peripheral groove Nozzle body tip end part 9 ... Nozzle body rear end part of circumferential groove

Continued on front page F term (reference) 3G066 AA07 AB02 AD12 BA02 BA03 BA17 BA26 BA56 CC10 CC14 CC26 CC34 CC41 CC48 CD30 DA09 DB08 DB09 DB12 DB13

Claims (17)

[Claims] A fuel injection nozzle having an injection hole communicating between the inside of the nozzle body and the outside of the nozzle body for injecting fuel to the outside of the nozzle body. The rear end of the inlet nozzle body overlaps the nozzle body front end of the circumferential groove,
The nozzle hole front end portion of the nozzle hole does not overlap with the circumferential groove, and the nozzle hole inlet is formed with respect to the circumferential groove so that the nozzle body rear end portion of the circumferential groove does not overlap with the nozzle hole inlet. The arranged fuel injection nozzle. 2. The nozzle body according to claim 1, wherein a portion of the wall surface of the peripheral groove on the tip side of the nozzle body, which is in contact with the inner wall surface of the nozzle body, faces outward in the radial direction of the nozzle body. Fuel injection nozzle. 3. The fuel injection nozzle according to claim 1, wherein, when a vertical cross section of the fuel injection nozzle is taken, a contour of a wall surface of a portion of the peripheral groove on a tip end side of the nozzle body draws a smooth concave curve. 4. A tapered surface is formed between a wall surface of a nozzle body rear end side portion of the circumferential groove and a nozzle body inner wall surface located at the nozzle body rear end side, and the tapered surface and a fuel injection nozzle are formed. The angle formed by the center axis, the angle formed by the inner wall surface of the nozzle body and the center axis of the fuel injection nozzle, and the angle formed by the wall surface of the nozzle body rear end side portion of the circumferential groove and the center axis of the fuel injection nozzle. 2. The fuel injection according to claim 1, wherein a wall surface of the peripheral groove at the rear end side of the nozzle body and the inner wall surface of the nozzle body located at the rear end side of the nozzle body are smoothly connected by setting the peripheral groove to a value between 2 and 3. nozzle. 5. A profile of a wall surface of a rear end side portion of the peripheral groove of the fuel injection nozzle and a contour of an inner wall surface of a nozzle body located at the rear end side of the nozzle body when a vertical cross section of the fuel injection nozzle is taken. 2. The fuel injection nozzle according to claim 1, wherein the fuel injection nozzle is made continuous through a smooth convex curve. 6. The fuel according to claim 1, wherein a needle valve is disposed inside the nozzle body, and a projection accommodated in the circumferential groove is disposed on the needle valve when the needle valve is located at the valve closing position. Injection nozzle. 7. The fuel injection nozzle according to claim 6, wherein, when a vertical cross section of the fuel injection nozzle is taken, a contour of a wall surface of the protrusion on the nozzle tip side draws a smooth concave curve. 8. The needle valve according to claim 1, wherein a needle valve is disposed inside the nozzle body, and the lift amount of the needle valve is reduced during low engine load operation, and the needle valve lift amount is increased during high engine load operation. Fuel injection nozzle. 9. The fuel according to claim 1, wherein a needle valve is disposed inside the nozzle body, the lift amount of the needle valve is reduced when the engine is running at a low speed, and the lift amount of the needle valve is increased when the engine is running at a high speed. Injection nozzle. 10. A needle valve disposed inside a nozzle body, wherein the lift amount of the needle valve is reduced when pilot injection is to be performed, and the lift amount of the needle valve is increased when main injection is to be performed. 3. The fuel injection nozzle according to 1. 11. A needle valve disposed inside a nozzle body, wherein the lift amount of the needle valve is reduced when post injection is to be performed, and the lift amount of the needle valve is increased when main injection is to be performed. 3. The fuel injection nozzle according to 1. 12. A fuel inflow passage is formed on the inner wall surface of the nozzle body on the rear end side of the nozzle body with respect to the circumferential groove, and the fuel inflow passage is circumferentially offset with respect to a center axis of a nearest injection hole. The fuel injection nozzle according to claim 1, wherein: 13. The fuel injection system according to claim 12, wherein a second peripheral groove is formed on a rear end side of the nozzle body with respect to the peripheral groove, and the peripheral groove and the second peripheral groove are connected by the fuel inflow passage. A fuel injection nozzle as described. 14. The fuel injection nozzle according to claim 13, wherein a needle valve is disposed inside the nozzle body, and the second peripheral groove is formed in the needle valve. 15. The fuel injection nozzle according to claim 12, wherein the fuel inflow passage is disposed on a center axis of an injection hole facing the center axis of the nozzle body. 16. The fuel injection nozzle according to claim 15, wherein the injection hole and the fuel inflow passage are formed by electric discharge machining so that the diameter of the fuel inflow passage is larger than the diameter of the injection hole. 17. A fuel injection nozzle having an injection hole communicating between the inside of the nozzle body and the outside of the nozzle body for injecting fuel to the outside of the nozzle body. The rear end portion of the nozzle body overlaps the nozzle body front end portion of the groove, and the nozzle body front end portion of the injection hole inlet does not overlap with the groove,
Further, the nozzle hole inlet is arranged in the groove so that the nozzle body rear end side portion of the groove does not overlap with the nozzle hole inlet, and a fuel inflow passage is provided in the nozzle body inner wall surface on the nozzle body rear end side of the groove. Wherein the fuel inflow passage is circumferentially offset with respect to the center axis of the nearest injection hole.