JP2007162535A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit influence of variation of fuel flow to an injection hole in a downstream side of a first injection hole and a second injection hole. <P>SOLUTION: In fuel injection valve provided with needles 60, 70 arranged double in inside and outside, and provided with a plurality of injection holes 10, 20 in a downstream part of a valve seat 30 including seat parts 31, 32, 33 which each needle 60, 70 are seated on and separated from, and selectively opening and closing part or all of the plurality of injection holes 60, 70 by lift of the needles 60, 70, a first injection hole 10 opening and closing by lift of the outer needle 60, and a second injection hole 20 arranged in a downstream side in fuel flow of the first injection hole 10 on the valve seat 30 are included, and a fuel flow path 45 between the inner needle 70 and the valve seat 30 quickly expands at an inlet part 21 of the second injection hole 20 when the inner needle 60 starts lifting after lift of the outer needle 70. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel injection valve, and is suitably applied to, for example, a fuel injection valve that injects fuel into an internal combustion engine.

  As a fuel injection device, for example, in a fuel injection device that directly injects fuel into a combustion chamber of an internal combustion engine, the fuel injection device includes two needles and a valve body that accommodates the needles so as to be movable in the axial direction. There is a fuel injection valve that makes this variable (see Patent Document 1, etc.).

  In the technique disclosed in Patent Document 1, two needles arranged inside and outside double, a valve seat provided in the valve body and shared by these needles, and formed in the valve seat, each needle (outer needle, inner needle) And the first nozzle hole and the second nozzle hole corresponding to each other, and selectively opening and closing the first nozzle hole and the second nozzle hole according to the needle lift, thereby making the nozzle hole area variable.

In this type of fuel injection valve, for example, the outer needle is lifted by adjusting the urging force of a spring that urges each needle toward the valve seat, and the fuel injection is started from the first injection hole by this lift, and thereafter The inner needle is lifted in the middle of lifting the outer needle, and fuel injection is started from the second injection hole.
JP 2002-276509 A

  However, in the prior art disclosed in Patent Document 1 and the like, since the needles are arranged in a double manner, there is a possibility that a unique problem that the variation in the flow rate of the fuel flowing into the nozzle hole becomes large. In general, the variation is caused by the axial misalignment of the needle. However, by arranging the needles double, the influence of the axial misalignment between the inner needle and the outer needle is added in addition to the axial misalignment between the outer needle and the valve body. Due to this axial shift, the seat portion fuel passage area around each nozzle hole portion varies greatly.

  Furthermore, with the double arrangement of the needles, the first injection hole and the second injection hole are arranged in this order with respect to the fuel flow, so that the fuel flow to the second injection hole is the upstream first injection hole. There is a possibility that the flow rate of fuel flowing into the second nozzle hole will vary greatly between the nozzle holes compared to the first nozzle hole.

  In addition, the applicant confirmed by spray observation that the spray reach distance from the second nozzle hole varies between the second nozzle holes. Due to this influence, not only does the air-fuel mixture formation in the cylinder fluctuate and become unstable, but it also causes a variation in the injection amount between cycles, which may cause a decrease in output. Due to this variation between cycles, engine vibration due to combustion increases, and there is a concern about noise deterioration.

  The present invention has been made in consideration of such circumstances, and in the case where needles are arranged in a double manner to selectively open and close the first injection hole and the second injection hole, the first injection hole and the second injection hole are provided. It aims at suppressing the influence by the dispersion | variation in the fuel flow to the downstream nozzle hole of two nozzle holes.

  Another object is to provide a fuel injection valve that alleviates the effects of variations in the passage area of the seat portion in order to prevent variations in the flow rate to the injection hole inlet.

  In order to achieve the above object, the present invention comprises the following technical means.

That is, according to the invention described in the claims, the needle is provided with double inside and outside, and a plurality of nozzle holes at the downstream portion of the seat portion on which each needle is seated and separated. In the fuel injection valve that selectively opens or closes some of the nozzle holes or all of the nozzle holes,
The needle has an inner needle and an outer needle that receive high-pressure fuel from the end on the seat side and can be separated independently,
The plurality of nozzle holes are provided as a first nozzle hole that opens and closes by a lift operation of the outer needle, and a second nozzle hole that is disposed downstream of the fuel flow of the first nozzle hole in the seat portion and opens and closes by the lift operation of the inner needle. Have
When the inner needle starts to lift after the outer needle is lifted, the fuel flow path between the inner needle and the seal portion is shaped to rapidly expand at the inlet portion of the second injection hole.

  According to this, since the fuel flow path between the inner needle that opens and closes the second nozzle hole and the seal part on which the inner needle is seated and separated is formed to rapidly expand at the inlet of the second nozzle hole, When the inner needle is lifted, it is possible to reduce the pressure change in the peripheral portion of the inlet between the nozzle holes, which is generated due to the influence of the flow rate fluctuation caused by the axis deviation. For example, when the inner needle is lifted, the prior art may immediately affect the inlet of the second nozzle hole due to a change in the gap area between the two that causes flow rate fluctuations due to axial deviation. Can be held.

  Therefore, it is possible to suppress a change in pressure between each nozzle hole at the nozzle inlet portion caused by variation in the fuel flow to the second nozzle hole located on the downstream side of the fuel flow in the first nozzle hole. As a result, variations in the fuel injection amount between the second nozzle holes and variations in the spray reach distance between the second nozzle holes, which are caused by variations in the fuel flow to the second nozzle holes, are suppressed.

Further, in the invention according to claim 2, a recess portion that rapidly expands the fuel flow path around the inlet portion is provided at a position facing the inlet portion of the inner needle and the second injection hole,
The recess is formed by stealing an inner needle.

  According to this, the inner needle is provided with a recess such as a clearance angle that rapidly expands the fuel flow path around the inlet portion of the second injection hole as a shape that rapidly expands the fuel flow path. As a result, the area of the fuel flow path can be enlarged, so that the influence of the fuel flow to the second injection hole due to the change in the area of the fuel flow path with respect to the lift of the inner needle can be suppressed as much as possible when an axial deviation occurs.

In the invention according to claim 3, the recess portion is located at a portion facing the seat portion of the inner needle and is different from an upstream seat surface formed on the upstream side of the inlet portion of the second injection hole. Having an inclined surface with an inclination angle;
The inclined surface is characterized in that the angle difference between the inclined surface and the seat portion is formed larger than the angle difference between the upstream seat surface and the seat portion.

  According to this, at the end portion on the seat portion side of the inner needle, the upstream seat surface formed on the upstream side of the inlet portion of the second injection hole and the inclination angle different from the upstream seat surface as the recess portion The angle difference between the inclined surface and the seat portion is set larger than the angle difference between the upstream seat surface and the seat portion. Thereby, since the inclined surface can increase the clearance angle from the seat portion as compared with the upstream seat surface on the upstream side of the inlet portion of the second nozzle hole, the inclined surface rapidly expands at the inlet portion of the second nozzle hole. Can be formed in a relatively simple inner needle shape.

  According to a fourth aspect of the present invention, the recess portion is formed with a concave portion that dents the inner needle at a position facing the inlet portion of the second injection hole of the inner needle.

  According to this, the recess portion provided in the inner needle is formed with a concave portion that dents the inner needle at a position facing the inlet portion of the second nozzle hole. It is possible to effectively suppress the influence of the fuel flow to the second nozzle hole due to the change in the area of the fuel flow path with respect to the above, and to reduce the dead volume around the second nozzle hole.

The invention according to claim 5 further comprises a valve body that has a seat portion and accommodates an outer needle disposed outside the inner needle so as to be movable in the axial direction.
At a position facing the inner needle and the inlet portion of the second injection hole, a recess portion is provided that rapidly expands the fuel flow path around the inlet portion,
The recess portion is formed by stealing the valve body.

  According to this, the valve body is provided with a recess portion such as a relief groove that rapidly expands the fuel flow passage around the inlet portion of the second injection hole as a shape that rapidly expands the fuel flow passage. As a result, the area of the fuel flow path can be enlarged, so that the influence of the fuel flow to the second injection hole due to the change in the area of the fuel flow path with respect to the lift of the inner needle can be suppressed as much as possible when an axial deviation occurs.

Further, in the invention according to claim 6, the recess portion is provided with a second concave portion that communicates between the seal portion and the inlet portion of the second injection hole, and dents the valve body,
The second concave portion is characterized in that the opening on the seat portion side is formed larger than the opening on the inlet portion side.

  According to this, the recess part provided in the valve body communicates between the seal part and the inlet part of the second injection hole, and the valve body is recessed so that the seat part side is opened larger than the inlet part side. Since the concave portion is formed, the fuel flow path can be reliably and rapidly expanded at the inlet portion of the second injection hole.

  The invention according to claim 7 is characterized in that the recess portion is formed in an annular shape in the circumferential direction of the seat portion of the body.

  According to this, since the inlet portion of each second injection hole communicates with the recess portion, the influence of the change in the area of the fuel flow path on the lift of the inner needle can be effectively mitigated in the case where the axial deviation occurs. Is possible. For example, since the fuel volume by the recess portion formed in an annular shape is increased, the sensitivity of the pressure fluctuation between the nozzle holes to the fluctuation of the inflowing fuel is reduced.

The invention according to claim 8 includes a valve body that has a seat portion and accommodates an outer needle disposed outside the inner needle so as to be movable in the axial direction.
The valve body is provided with a sac chamber for storing fuel on the downstream side of the seat part,
The second nozzle hole is characterized by opening in the inner wall of the sac chamber.

  Accordingly, as a means for rapidly expanding the fuel flow path, a sac chamber for storing fuel is provided in the valve body having the seat portion on the downstream side of the seat portion, and the second injection hole is opened on the inner wall of the sac chamber. It is preferable to configure. Thereby, when there are a plurality of second nozzle holes, all the second nozzle holes are opened in the inner wall of the sac chamber, so that the influence of the variation in the fuel flow between the second nozzle holes due to the misalignment can be more effectively achieved. It is possible to relax.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments in which a fuel injection valve of the present invention is embodied will be described with reference to the drawings.

(First embodiment)
Drawing 1 is a typical fragmentary sectional view showing the composition of the fuel injection valve of an embodiment. FIG. 2 is a partial cross-sectional view showing the main part of the fuel injection nozzle in FIG. FIG. 3 is a schematic cross-sectional view showing a fuel flow path around the inner needle and the second injection hole in FIG. 2. FIG. 4 is a schematic cross-sectional view showing the fuel flow path when the inner needle in FIG. 2 is misaligned. 3 and 4 show a state in which the inner needle has started to lift.

  The fuel injection valve 1 constitutes a part of a fuel injection device (not shown) for injecting and supplying fuel to, for example, a cylinder of a diesel engine (not shown: hereinafter referred to as an engine). This fuel injection device includes a high-pressure pump (not shown) that pumps up and discharges fuel from a fuel tank and discharges the high-pressure fuel discharged from the high-pressure pump to a pressure corresponding to an injection pressure (hereinafter referred to as a common rail pressure). A common rail (not shown) for accumulating pressure, a fuel injection valve 1 for supplying high-pressure fuel to the engine cylinder, and a control device (not shown: ECU, hereinafter) for controlling the operation of the high-pressure pump, fuel injection valve 1 and the like Called).

  The fuel injection valve 1 has a substantially cylindrical shape, receives fuel from a fuel introduction section (not shown) (in the direction of the arrow indicating fuel inflow in the figure), and injects fuel from the tip via internal fuel passages 50 and 42. . As shown in FIG. 1, the fuel injection valve 1 includes a needle driving mechanism (hereinafter referred to as a nozzle holder) 2 that drives the needles 60 and 70 and a nozzle body (hereinafter referred to as a fuel injection nozzle) 4. Has been. The nozzle holder portion 2 and the fuel injection nozzle 4 are oil-tightly fixed to each other by a fastening member 90 such as a substantially cylindrical retaining nut with the plate portion 3 sandwiched between the nozzle holder portion 2 and the fuel injection nozzle 4. ing.

  The fuel injection nozzle 4 includes a nozzle body 5 as a valve body, an outer needle 60, an inner needle 70, a biasing member (hereinafter referred to as a first spring) 80 that biases the outer needle 60, and an inner needle 70. And a second spring 81 for energizing.

  The nozzle body 5 is formed in a substantially bottomed cylindrical shape, and an accommodation hole 40 for accommodating the outer needle 60 and the inner needle 70 in a reciprocating manner in the axial direction is provided therein. The front end portion 6 of the nozzle body 5 is provided with a first injection hole 10 and a second injection hole 20 that penetrate through the accommodation hole 40 and the outer wall surface of the nozzle body 5 in and out.

  A fuel passage 42 is formed in the nozzle body 5 between the outer periphery of the outer needle 60 and the accommodation hole 40, and the fuel passage 42 is a high-pressure fuel supplied to the first injection hole 10 and the second injection hole 20. The fuel flow path is configured. The fuel passage 42 communicates with a fuel passage 50 formed in the plate portion 3 and is supplied with high-pressure fuel from a common rail.

  As shown in FIG. 2, a common valve seat 30 on which the outer needle 60 and the inner needle 70 are seated and separated is formed on the front end 6 side of the accommodation hole 40. The valve seat 30 is arranged in the order of the first injection hole 10 and the second injection hole 20 toward the downstream side of the fuel flow, and a seal on which the contact portions 61 and 62 of the outer needle 60 are seated and separated. The portions 31 and 32 and the seal portion 33 on which the contact portion 71 of the inner needle 70 is seated and separated are provided. The seal part (hereinafter referred to as a first seal part) 31 and the second seal part 32 are arranged with the first injection hole 10 interposed therebetween. Further, the third seal portion 33 is disposed on the upstream side of the fuel flow in the second nozzle hole 20, and is disposed on the downstream side of the second seal portion 32.

  As shown in FIG. 1, the outer needle 60 is formed in a substantially hollow cylindrical shape, and a first spring 80 is provided on the end side opposite to the first injection hole 10 side. The outer needle 60 is constantly urged toward the direction in which the first injection hole 10 is provided by the urging force of the first spring 80. Hereinafter, the direction in which the nozzle holes are present is referred to as the nozzle hole direction, and the opposite direction is referred to as the counter nozzle hole direction.

  As shown in FIG. 2, the outer needle 60 has a concave groove (hereinafter referred to as a concave groove) 11 with the first contact portion 61 and the second contact portion 62 interposed therebetween. The concave groove 11 is disposed so as to face the inlet portion 11 of the first nozzle hole 10 and is formed in a circular shape on a truncated cone surface (hereinafter referred to as a first truncated cone surface) 64. The first abutting portion 61 and the second abutting portion 62 are configured so that the first abutting portion 71 can be moved when the outer needle 60 is seated on the seal portions 31 and 32 during the lifting operation of the outer needle 60. The seating on the seal portion 31 can be performed earlier than the seating on the second seal portion 32 of the second contact portion 72, and the first seal portion 31 and the second seal of the first contact portion 61 and the second contact portion 62 are achieved. Ensure seating on part 32.

  Note that high pressure fuel is guided to the end portion of the outer needle 60 on the first injection hole 10 side via the fuel passage 42, and the first truncated cone surface 64 is a pressure receiving surface (hereinafter referred to as pressure receiving surface) that receives high pressure fuel. , First pressure receiving surface).

  As shown in FIG. 1, an inner needle 70 formed in a substantially cylindrical shape is accommodated inside the outer needle 60 so as to be reciprocally movable in the axial direction. A second spring 81 is provided on the side of the inner needle 70 opposite to the injection hole. The inner needle 70 is always urged in the direction of the injection hole by the urging force of the second spring 81.

  As shown in FIG. 2, a second pressure receiving surface 72, a second truncated cone surface 74, and a conical surface 75 are provided at the end of the inner needle 70 on the first injection hole 10 side toward the downstream side of the fuel flow. It is provided in order. The third contact portion 73 is formed by a ridge line between the second truncated cone surface 74 and the conical surface 75. The second truncated cone surface 74 constitutes a seal surface (hereinafter, upstream seal surface) formed on the upstream side of the inlet portion 21 of the second injection hole 20, and the conical surface 75 is connected to the upstream seal surface 74. Different slopes are constructed.

  Here, the first contact portion 71 and the second contact portion 72, and the first seal portion 31 and the second seal portion 32, the contact portions 71 and 72 are in contact with and separated from the seal portions 31 and 32, respectively. By sitting, the fuel flow to the inlet 11 of the first nozzle hole 10 is blocked and allowed. Further, the third abutting portion 73 and the third seal portion 33 are configured such that the fuel to the inlet portion 21 of the second injection hole 20 is obtained when the third abutting portion 73 abuts and separates from the third seal portion 33. Block and allow flow. When the high pressure fuel acts on the first pressure receiving surface 65 and the second pressure receiving surface 72 on the outer needle 60 and the inner needle 70, a force is generated to push up the outer needle 60 and the inner needle 70 in the anti-injection hole direction, respectively.

  As shown in FIG. 1, a pressure control chamber 41 that is surrounded by a wall surface in the plate portion 3 is provided on the side opposite to the injection holes of the needles 60 and 70. The high pressure fuel from the common rail is also supplied to the pressure control chamber 41 through a fuel passage (not shown).

  The fuel pressure in the pressure control chamber 41 generated in each of the needles 60, 70, the force in the injection hole direction due to the urging force of the springs 80, 81, and the anti-injection direction due to the fuel pressure in the fuel passage 42. The separation seat between the needles 60 and 70 and the seal portions 31, 32, and 33 is determined by the balance with the force.

  Specifically, in the outer needle 60, when the force in the injection hole direction is greater than the force in the counter injection hole direction, the first contact part 61 and the second contact part 62 are connected to the first seal part 31 and the second contact part 62, respectively. The fuel is not injected from the first injection hole 10 while sitting on the seal portion 32. On the other hand, when the force in the direction opposite to the injection hole is greater than the force in the direction of the injection hole, the first contact part 61 and the second contact part 62 are separated from the first seal part 31 and the second seal part 32. Then, the fuel is injected from the first injection hole 10.

  Further, in the inner needle 70, when the force in the injection hole direction exceeds the force in the anti-injection hole direction, the third contact portion 71 is seated on the third seal portion 33, and the fuel is discharged from the second injection hole 20 to the fuel. Is not jetted. On the other hand, when the force in the direction opposite to the injection hole exceeds the force in the direction of the injection hole, the third contact part 71 is separated from the third seal part 33 and fuel is injected from the second injection hole 20. .

  By adjusting the balance of these forces, the fuel injection can be controlled. Specifically, the balance of these forces can be adjusted by adjusting the fuel pressure in the pressure control chamber 41. Adjustment of the fuel pressure in the pressure control chamber 41 is performed by a control valve (not shown) provided in the middle of the fuel passage in the nozzle holder portion 2 that connects the pressure control chamber 41 and a fuel tank (not shown). The operation of the control valve is controlled by a command from the ECU, and the valve is opened to return the fuel in the pressure control chamber 41 to the fuel tank and reduce the pressure. Further, the high pressure fuel supplied from the common rail is accumulated in the pressure control chamber 41 by closing the control valve.

  When fuel is injected from each nozzle hole 10, 20, the control valve is opened under the control of the ECU, and the pressure in the pressure control chamber 41 is gradually reduced. When the pressure decreases, the force in the anti-nozzle direction generated in the outer needle 60 is won, and the first and second contact portions 61 and 62 are separated from the first and second seal portions 31 and 32, and the first injection Fuel is injected from the hole 10. At substantially the same time, the high-pressure fuel in the fuel passage 42 is supplied to the second pressure receiving surface 72 of the inner needle 70.

  Further, when the pressure in the pressure control chamber 41 decreases, the force in the anti-injection hole direction generated in the inner needle 70 is won, the third contact part 71 is separated from the third seal part 33, and the second injection hole 20. Fuel is also injected from.

  When stopping fuel injection from the nozzle holes 10 and 20, the control valve is closed under the control of the ECU, and the pressure in the pressure control chamber 41 is gradually increased to the common rail pressure of the high-pressure fuel supplied from the common rail. . When the pressure rises, the force in the direction of the nozzle hole generated in each needle 60, 70 is won, and each contact part 61, 62, 71 is seated on each seal part 31, 32, 33, and the first and second nozzle holes Fuel injection from 10 and 20 is stopped.

  Here, in the present embodiment, when the inner needle 70 is opened, when the outer needle 70 starts to lift, the fuel flow path between the end of the inner needle 70 on the second injection hole 20 side and the valve seat 30 becomes the first. The two nozzle holes 20 are configured to expand rapidly at the inlet 21. Specifically, as shown in FIG. 3, when the inner needle 70 is opened, the fuel passage 45 is interposed between the second truncated cone surface 74 and the conical surface 75 of the inner needle 70 and the third seal portion 33 of the valve seat 30. Is formed. The angle difference α2 between the conical surface 75 and the valve seat 30 is formed larger than the angle difference α1 between the second truncated cone surface 74 and the valve seat 30.

  As a result, the conical surface 75 can have a larger clearance angle from the valve seat 30 than the second truncated cone surface 74 on the upstream side of the second nozzle hole 20, so that the fuel passage 45 can be connected to the inlet of the second nozzle hole 20. Part 21 can be enlarged rapidly.

  Here, the clearance angle from the valve seat 30 is such that, in the inner needle 70, the conical surface 75 moves from the valve seat 30 toward the downstream side with respect to the valve seat 30 as shown in FIGS. 2 and 3. The angle difference α2 is set so as to be far away. Further, in the outer needle 60, as shown in FIG. 2, the angle difference between the first truncated cone surface 65 and the valve seat 30 is almost zero, or the angle difference is further away from the valve seat 30 toward the upstream side. Is set.

  Further, in the present embodiment, as shown in FIGS. 2 and 3, the tip portion 6 of the nozzle body 5 is provided with a sac chamber 46 for storing fuel on the downstream side of the valve seat 30. Twenty inlet portions 21 open in the inner wall of the sack chamber 46. The sac chamber 46 is partitioned by a conical surface 75 and an inner wall of the sac chamber 46, and has a predetermined bag-like volume for a fuel reservoir.

  The arrangement position of the second injection hole 20 is not limited to the arrangement of the second injection hole 20 on the inner wall of the sack chamber 46, and the second injection hole is provided in the valve seat 30 as long as it is downstream of the third seal portion 33. It may be arranged.

  Here, the conical surface 75 formed on the inner needle 70 has a recess 77 that rapidly expands the fuel passage 45 around the inlet at a portion facing the inlet 21 of the second injection hole 20 of the inner needle 70. Constitute. The recess 77 can be obtained by stealing the inner needle 70 with the conical surface 75 with respect to the second truncated cone surface 74.

  Next, the fuel flow to the fuel injection valve having the above-described configuration, in particular, the second injection hole located on the downstream side of the first injection hole 10 and opened and closed by the lift drive of the inner needle 70 will be described with reference to FIG. FIG. 4 shows the fuel passage around the second injection hole when the inner needle 70 is misaligned.

  11 to 13 show a fuel injection nozzle 904 of a comparative example for explaining the effect of the present embodiment. FIG. 13 shows an axial misalignment of the inner needle 970 in the fuel injection valve 904 of the comparative example. The fuel passage 945 around the second nozzle hole 20 is shown.

  In the fuel injection nozzle 904 of the comparative example, in the fuel passage 945 between the inner needle 970 and the valve seat 30, as shown in FIGS. 11 and 12, there is an angle difference α 1 between the second truncated cone 974 and the valve seat 30. The angle difference is set to almost zero or slightly downstream. For this reason, as shown in FIG. 13, when the shaft 970 j of the inner needle 970 is misaligned with respect to the shaft 5 j of the nozzle body 5, the fuel passage 945 has a one-side fuel in which the flow width of the fuel flow is reduced. A passage portion 945n and an opposite one-side fuel passage portion 945w having a passage width expanding on the opposite end side of the one-side fuel passage portion 945 (on the left side in FIG. 13 for convenience) are generated.

  In such a fuel injection nozzle 904 of the comparative example, a difference occurs in the area of the flow path of the axial displacement of the inner needle 970 flowing to the inlet portion 21 of each second injection hole 20. As a result, the fuel flow rate of the fuel flow flowing into the inlet portion 21n is reduced in the second nozzle hole 20n on the one-side fuel passage portion 945n side. On the other hand, the fuel flow rate of the fuel flow flowing into the inlet portion 21w increases in the second nozzle hole 20w in the opposite one-side fuel passage portion 945w. As a result, the fuel flow flowing into the inlet portion 21 varies between the second injection holes 20, and the fuel flow rate of the fuel injected from the second injection holes 20 varies between the second injection holes 20.

  On the other hand, in this embodiment, in the fuel passage 45 between the second truncated cone surface 74, the conical surface 75, and the valve seat 30, the clearance angle from the valve seat 30 to the conical surface 75 is caused by the opening degree difference α2. Since it can be formed larger than the second truncated cone surface 74, the fuel passage 45 can be rapidly enlarged at the inlet portion 21 of the second injection hole 20. As a result, the flow passage area of the fuel passage 45 can be enlarged, so that the influence of the fuel flow to the second injection hole 20 due to the fluctuation of the flow passage area of the fuel passage 45 can be suppressed as much as possible when an axial deviation occurs. Can do. As shown in FIG. 6, the second nozzle holes 20n, 20w may be the second nozzle holes 20n on the one-side fuel passage part 45n side or the second nozzle holes 20w on the opposite one-side fuel path part 45w. Variations in the fuel flow flowing into the inlet portions 21n and 21w can be suppressed.

  The second nozzle hole 20 is preferably open on the inner wall of the sac chamber 46. In the fuel passage 45 of the present embodiment, when the fuel flow rate difference is suppressed between the one-side fuel passage portion 45n and the opposite one-side fuel passage portion 45w, but there is still a slight difference, the fuel flows are merged into the sac chamber 46 and fuel is stored. The difference is further alleviated by the fuel flow.

  Next, the operation and effect of this embodiment will be described. In this embodiment, when the inner needle 70 starts to lift, the inner needle 70 that opens and closes the second injection hole, and the inner needle 70 are seated and separated. Since the fuel passage 45 between the valve seat 30 and the third seal portion 33 has a shape that rapidly expands at the inlet portion 21 of the second injection hole 20, the second injection hole 20 n that may be caused by an axis deviation, Variations in the fuel flow flowing into the inlet portions 21n and 21w during 20w can be suppressed.

  Therefore, even if the fuel flow path between the outer needle 60 and the seal portions 31 and 32, for example, on the upstream side of the second nozzle hole 20 due to an axial deviation or the like may be generated, the fuel flow path may be reduced. In the fuel passage 45 to which fuel is supplied via, the influence of the fuel flow flowing from the fuel passage 45 into the second nozzle hole 20 on the pressure loss (pressure loss) and the like can be mitigated. As a result, it is possible to suppress variation in the fuel flow to the second nozzle hole 20 located on the downstream side of the first nozzle hole 10, and accordingly, due to variation in the fuel flow to the second nozzle hole 20. Variations in the fuel injection amount between the second nozzle holes 20 and variations in the spray reach distance between the second nozzle holes 20 are suppressed.

  In the present embodiment, the fuel passage 45 has a shape that rapidly expands, and the inner needle 70 has a recess portion that forms a clearance angle for rapidly expanding the flow path around the inlet portion 21 of the second injection hole 20. A conical surface 75 as 77 is provided. By providing such a recess portion 77, the flow passage area of the fuel passage 45 can be enlarged at the inlet portion 21, so that the second injection due to the fluctuation of the flow passage area of the fuel passage 45 when an axial deviation occurs. The influence of the fuel flow on the hole 20 can be minimized.

  Further, in order to realize a shape that rapidly expands the fuel passage 45, in the present embodiment, the inner needle 70 is formed at the end portion on the seat portion 33 side upstream of the inlet portion 21 of the second injection hole 20. The upstream seat surface (second truncated cone surface) 74 and a conical surface 75 having a different inclination angle from the upstream seat surface 74 as the recess portion 77 are provided. The conical surface 75 and the seat portion 33 are provided. Is set to be larger than the angle difference α1 between the upstream seat surface 74 and the valve seat 30. Accordingly, the conical surface 75 can set the clearance angle from the seat portion 33 to be larger than that of the upstream seat surface 74.

  Therefore, the flow path shape of the fuel passage 45 that rapidly expands at the inlet 21 of the second injection hole 20 can be formed by a relatively simple inner needle 70 shape.

  In the present embodiment, the second injection hole 20 is preferably configured to open to the inner wall of the sac chamber 46 formed on the downstream side of the valve seat 30. Thereby, when there are a plurality of second injection holes 20, all of the second injection holes 20 are opened in the inner wall of the sac chamber 46, so that the influence of variations in the fuel flow between the second injection holes 20 due to axial misalignment. Can be more effectively mitigated.

  For example, in the fuel passage 45 of this embodiment, when the fuel flow rate difference between the one-side fuel passage portion 45n and the opposite one-side fuel passage portion 45w is suppressed, but the difference still remains, the fuel passage 45 joins the sac chamber 46 and stores the fuel. The difference is further alleviated by the fuel flow.

(Second Embodiment)
Hereinafter, other embodiments to which the present invention is applied will be described. In the following embodiments, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals, and description thereof will not be repeated.

  In the second embodiment, in the shape of the recess portion provided in the inner needle 70 described in the first embodiment, instead of the conical surface 75 that increases the clearance angle from the valve seat 30, as shown in FIG. A concave portion 173 is formed on the second truncated cone surface 174 in a concave shape. FIG. 5 is a partial cross-sectional view showing the main part of the fuel injection nozzle according to the present embodiment. FIG. 6 is a schematic cross-sectional view showing the fuel flow path when the inner needle in FIG. 5 is misaligned.

  As shown in FIG. 5, the fuel injection nozzle 104 includes a nozzle body 105, an outer needle 60, and an inner needle 170.

  The nozzle body 105 is different from the nozzle body 5 of the first embodiment in that the second injection hole 20 is formed in the valve seat 30. Note that the second injection hole 20 is not disposed on the inner wall of the sac chamber 146.

  As shown in FIGS. 5 and 6, a second truncated cone surface 174 and a conical surface 175 are formed on the end portion side of the second injection hole 20 of the inner needle 170. The conical surface 175 is configured to partition the sac chamber together with the second truncated cone surface 175. The conical surface 175 is not disposed at a position facing the second nozzle hole 20 while the second truncated cone surface 174 is disposed at a position facing the second nozzle hole 20. For this reason, during the lifting operation of the inner needle 170, only the second truncated cone surface 174 faces the seal portion 133 on the second injection hole 20 side, and the fuel passage 145 has the second truncated cone surface 174 and the valve seat 30. And will be formed.

  The second truncated cone surface 174 is formed with a concave concave portion (hereinafter referred to as a second concave groove) 173 sandwiched between the third contact portions 171a and 171b. One (hereinafter referred to as one contact portion) 171a of the third contact portions 171a and 171b is seated on and separated from one (hereinafter referred to as one seal portion) 33a of the third seal portions 33a and 33b on the valve seat 30 side. Sitting is possible. Further, the other (hereinafter referred to as the other contact portion) 171b of the third contact portions 171a and 171b can be seated and separated from the other (hereinafter referred to as the other seal portion) 33b of the third seal portions 33a and 33b. .

  The second injection hole 20 is disposed in the valve seat 30 between the one seal portion 33a and the other seal portion 33b.

  In the above-described configuration, any one may be used as long as the one abutting portion 171a on the upstream side of the fuel flow with respect to the second nozzle hole 20 and the one seal portion 33a can be seated oiltightly. For example, when the inner needle 170 is seated on the valve seat 30 (specifically, the one seal portion 33a), the other contact portion 171b and the other seal portion 33b may not be seated.

  In some cases, while the inner needle 170 is seated on the valve seat 30, the other contact portion 171b and the other seal portion 33b are not seated, and a slight gap is formed between the other contact portion 171b and the other seal portion 33b. May occur. Even in such a configuration, the second injection hole 20 and the sac chamber 146 are merely communicated with each other through a slight gap. Therefore, when the inner needle 170 is closed, the second injection hole is substantially provided. 20 and the suck chamber 146 are closed.

  Here, the second concave groove 173 as a concave portion formed in the inner needle 170 is abrupt in the fuel passage 145 around the inlet at a portion facing the inlet portion 21 of the second injection hole 20 of the inner needle 170. A recess 177 to be enlarged is configured. The recess 177 can be obtained by stealing the inner needle 70 so as to be recessed with the second concave groove 173 with respect to the second truncated cone surface 174.

  Even in such a configuration, the fuel passage 145 can be rapidly expanded at the inlet 21 due to the second concave groove 173 disposed at a position facing the inlet 21 of the second injection hole 20. Therefore, an effect equivalent to that of the first embodiment can be obtained.

  Furthermore, in the present embodiment, when the inner needle 170 is closed, the second injection hole 20 and the sac chamber 146 are closed, so that the dead volume around the second injection hole 20 can be reduced.

(Third embodiment)
In the second embodiment, the inner needle 170 is provided with a recess 177 that rapidly expands the fuel passage 145 around the inlet.

  In contrast, in the third embodiment, as shown in FIG. 7, the nozzle body 205 is provided with a recess 237 that rapidly expands the fuel passage 245 around the inlet. FIG. 7 is a partial cross-sectional view showing the main part of the fuel injection nozzle according to the present embodiment. FIG. 8 is a schematic cross-sectional view showing the fuel flow path when the inner needle in FIG. 7 is misaligned. FIG. 9 is an arrow view of the valve body in FIG. 7 as viewed from the inside toward the inlet of the second nozzle hole.

  As shown in FIG. 7, the fuel injection nozzle 204 includes a nozzle body 205, an outer needle 60, and an inner needle 270.

  The inner needle 270 differs from the inner needle 170 of the second embodiment in that no meat stealing is provided on the second truncated cone surface 174.

  On the valve seat 30 of the nozzle body 205, the first and second seal portions 31, 32 on which the contact portions 61, 62 of the outer needle 60 are seated and separated, and the contact portion 71 of the inner needle 270 are seated and separated. A sitting third seal portion 33 is provided.

  As shown in FIG. 7, the second injection hole 20 and the second concave portion (hereinafter referred to as an annular groove) 236 as the recess portion 237 are provided in the valve seat 30 on the downstream side of the third seal portion. Yes. The annular groove 236 is disposed between the third seal portion 33 and the inlet portion 21 of the second injection hole 20 so that the third seal 33 and the inlet portion 21 are always communicated with each other by the annular groove 236 in the fuel flow. It has become.

  As shown in FIG. 7, the annular groove 236 is formed so that the opening on the third seat portion 33 side (upstream side of the fuel flow) is larger than the opening on the inlet portion 21 side (downstream side of the fuel flow).

  According to this, the recess part 237 provided in the nozzle body 205 communicates between the third seal part 33 and the inlet part 21 of the second injection hole 20, and the third sheet part 33 side is larger than the inlet part 21 side. Since the annular groove 236 that dents the nozzle body 205 so as to open is formed, the fuel flow path 245 can be surely and rapidly expanded at the inlet 21 of the second injection hole 20 (see FIG. 8).

  Furthermore, in this embodiment, as shown in FIGS. 7 and 9, the annular groove 236 is preferably formed in an annular shape in the circumferential direction along the third seal portion 33 of the valve seat 30. Thereby, the inlet part 21 of each 2nd injection hole 20 is always mutually connected by the annular groove 236 (refer FIG. 9).

  Even in such a configuration, the fuel passage 245 can be shaped to rapidly expand at the inlet portion 21 due to the annular groove 236 formed in the nozzle body 205, so that an effect equivalent to that of the second embodiment is obtained. be able to.

  Furthermore, in this embodiment, since the annular groove 236 is formed annularly in the circumferential direction along the valve seat 30, the inlet portion 21 of each second injection hole 20 communicates with the annular groove 236. When the deviation occurs, it is possible to prevent the variation of the area of the fuel flow path 245 with respect to the lift of the inner needle 270. Therefore, when an axial deviation occurs, it is possible to prevent the influence of the fuel flow to the second injection hole 20 due to the change in the flow path area of the fuel passage 45.

(Fourth embodiment)
In the fourth embodiment, in place of the annular groove 236 described in the third embodiment, as shown in FIG. 10, a relief groove 336 provided around the inlet portion 21 is provided for each second injection hole 20. FIG. 10 is an arrow view of the valve body according to the present embodiment as viewed from the inside toward the inlet portion of the second nozzle hole.

  The fuel injection nozzle 304 includes a nozzle body 305, an outer needle 60, and an inner needle 270.

  The nozzle body 305 is different from the nozzle body 205 of the third embodiment only in the escape groove 336 provided around the inlet portion 21 for each second nozzle hole 20 described above.

  Even with such a configuration, the fuel passage 245 can be shaped to rapidly expand at the inlet portion 21 due to the escape groove 336 formed in the nozzle body 305, so that an effect equivalent to that of the third embodiment is obtained. be able to.

  Furthermore, in the present embodiment, the escape groove 336 is provided limited to the periphery of the inlet portion 21 for each second nozzle hole 20, so that the waste volume of the recess portion due to the escape groove 336 can be reduced.

(Other embodiments)
(1) In the present embodiment described above, the second conical surface is used as the recesses 77 and 177 provided in the inner needles 70 and 170 for rapidly expanding the fuel passages 45 and 145 at the inlet 21 of the second injection hole 20. A conical surface 75 that increases the clearance angle from the valve seat 30 compared to 74 and a concave portion 173 formed on the second conical surface 174 are used. The shape is not limited to the conical surface 75 and the concave portion 173, but may be any shape as long as the fuel passages 45 and 145 rapidly expand at the inlet portion 21 of the second injection hole 20.

  (2) In the present embodiment described above, the second nozzle hole is described as being disposed on the downstream side of the first nozzle hole and the second nozzle hole. The hole may be disposed on the downstream side.

  (3) In the present embodiment described above, the recesses 77, 177, and 277 are provided in any of the inner needles 70 and 170 and the nozzle bodies 205 and 305. The recess portion is not limited to such a configuration, and may be configured to be provided on both the inner needle and the nozzle body.

It is a typical fragmentary sectional view showing composition of a fuel injection valve of a 1st embodiment of the present invention. It is a fragmentary sectional view which shows the principal part of the fuel-injection nozzle in FIG. FIG. 3 is a schematic cross-sectional view showing a fuel flow path around an inner needle and a second injection hole in FIG. 2. FIG. 3 is a schematic cross-sectional view showing a fuel flow path when the inner needle in FIG. 2 is misaligned. It is a fragmentary sectional view showing the principal part of the fuel injection nozzle concerning a 2nd embodiment. FIG. 6 is a schematic cross-sectional view showing a fuel flow path when the inner needle in FIG. 5 is misaligned. It is a fragmentary sectional view showing the principal part of the fuel injection nozzle concerning a 3rd embodiment. FIG. 8 is a schematic cross-sectional view showing a fuel flow path when the inner needle in FIG. 7 is misaligned. It is the arrow view which looked at the valve body in FIG. 7 from the inside toward the inlet_port | entrance part of a 2nd nozzle hole. It is the arrow directional view which looked at the valve body concerning 4th Embodiment from the inside toward the inlet_port | entrance part of a 2nd nozzle hole. It is a fragmentary sectional view showing the principal part of the fuel injection nozzle of a comparative example. FIG. 12 is a schematic cross-sectional view showing an inner needle and a fuel flow path around a second injection hole in FIG. 11. FIG. 12 is a schematic cross-sectional view showing a fuel flow path when the inner needle in FIG. 11 is misaligned.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection valve 2 Nozzle holder part (needle drive mechanism part)
4 Fuel injection nozzle (nozzle body)
5 Nozzle body (valve body)
6 tip portion 10 first nozzle hole 20 second nozzle hole 21 inlet portion 30 valve seat 31 first seal portion (seal portion)
32 Second seal part (seal part)
33 Third seal part (seal part)
45 Fuel flow path 46 Suck chamber 60 Outer needle 61 First contact part (contact part)
62 2nd contact part (contact part)
65 First truncated cone surface (first pressure receiving surface)
70 Inner needle 71 Third contact portion (contact portion)
72 Second pressure-receiving surface 74 Second truncated cone surface (upstream seal surface)
75 Conical surface (inclined surface)

Claims (8)

A needle arranged in an inner and outer double, and a plurality of injection holes in the downstream part of the seat part on which each needle is seated and separated, and a part of the injection holes and all of the injection holes by the lift operation of the needle In a fuel injection valve that selectively opens and closes any of the nozzle holes,
The needle has an inner needle and an outer needle that receive high-pressure fuel from an end on the seat portion side and can be separated independently,
The plurality of nozzle holes are disposed on the downstream side of the fuel flow of the first nozzle hole in the seat portion, and are opened and closed by the lift operation of the inner needle. A second nozzle hole,
When the inner needle starts to lift after the outer needle is lifted, the fuel flow path between the inner needle and the seal portion is configured to rapidly expand at the inlet portion of the second injection hole. Fuel injection valve. In a position facing the inner needle and the inlet portion of the second injection hole, a recess portion is provided that rapidly expands the fuel flow path around the inlet portion,
The fuel injection valve according to claim 1, wherein the recess is formed by stealing the inner needle. The recess portion is a portion facing the seat portion of the inner needle, and has an inclined surface having an inclination angle different from an upstream seat surface formed upstream of the inlet portion of the second injection hole. Have
3. The inclined surface according to claim 2, wherein an angle difference between the inclined surface and the seat portion is formed larger than an angle difference between the upstream seat surface and the seat portion. Fuel injection valve.   3. The fuel injection according to claim 2, wherein the recess portion is formed with a concave portion that dents the inner needle at a position facing the inlet portion of the second injection hole of the inner needle. valve. A valve body having the seat portion and accommodating the outer needle disposed outside the inner needle so as to be movable in the axial direction;
In a position facing the inner needle and the inlet portion of the second injection hole, a recess portion is provided that rapidly expands the fuel flow path around the inlet portion,
The fuel injection valve according to claim 1, wherein the recess portion is formed by stealing the valve body. The recess portion communicates between the seal portion and the inlet portion of the second nozzle hole, and is provided with a second concave portion that dents the valve body,
6. The fuel injection valve according to claim 5, wherein the second concave portion is formed so that the opening on the seat portion side is larger than the opening on the inlet portion side.   The fuel injection valve according to claim 5 or 6, wherein the recess portion is formed in an annular shape in a circumferential direction of the seat portion of the valve body. A valve body having the seat portion and accommodating the outer needle disposed outside the inner needle so as to be movable in the axial direction;
The valve body is provided with a sac chamber for storing fuel on the downstream side of the seat portion,
The fuel injection valve according to any one of claims 1 to 4, wherein the second injection hole opens in an inner wall of the sac chamber.

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