JP4297504B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve.

In a port injection engine that injects fuel into an intake port, it is known that the spray injected into the intake port adheres to the wall surface of the intake port and the intake valve. Hereinafter, the fuel adhesion to the wall surface of the intake port will be described.
FIG. 12A is a schematic diagram showing the spray injected during the non-intake stroke, and FIG. 12B is a schematic diagram showing the spray injected during the intake stroke. When the fuel is injected during the non-intake stroke, the spray floating in the intake port adheres to the wall surface of the intake port as shown in FIG. When fuel is injected during the intake stroke, the spray is pushed by the intake air as shown in FIG. 12B, and the amount attached to the wall surface of the intake port further increases. If fuel adheres to the wall surface of the intake port or the intake valve, the attached fuel becomes liquid and flows into the combustion chamber, and the combustibility deteriorates. As a result, exhaust emission and fuel consumption deteriorate.

In Patent Documents 1 and 2, the shape of the injection hole is formed in a substantially semicircular arc shape or a substantially “<” shape so as to prevent fuel from adhering to the vicinity of the center of the intake valve, A fuel injection valve that prevents fuel from adhering to the wall surface of an intake port by injecting a spray within a range of a tangent line that connects the parts is disclosed.
Patent Document 3 discloses a fuel injection method for transporting spray using an intake air flow control device. In the fuel injection method described in Patent Document 3, the intake flow is generated in synchronization with the injection during the intake stroke, and the spray is carried on the intake flow to prevent the fuel from adhering to the wall surface of the intake port and the intake valve. is doing.

Japanese Patent Laid-Open No. 08-218986 JP 08-326636 A JP 2001-317434 A

However, as long as fuel is injected into the intake port, it is not possible to completely prevent the fuel from adhering to the wall surface of the intake port. The farther the distance to the intake valve is, the more fuel adheres to the wall surface of the intake port. In other words, if the distance between the nozzle hole and the intake valve is reduced, fuel adhesion to the wall surface of the intake port can be further reduced.
However, according to the fuel injection valves described in Patent Documents 1 and 2, since the fuel is injected substantially in the valve shaft direction, when the fuel injection valve is brought close to the intake valve, the spray is optimally aimed along the outer periphery of the intake valve. It deviates from the position and range, and directly collides with the vicinity of the center of the intake valve. Therefore, there is a problem that the fuel injection valve cannot be brought close to the intake valve. It is possible to change the spray angle by inclining the nozzle hole, thereby bringing the fuel injection valve closer to the intake valve without removing the spray from the optimum target position. However, in general, in the fuel injection valve, the inclination angle of the injection hole does not coincide with the injection angle of the fuel, and the fuel injection angle is shallower than the inclination angle of the injection hole. It is possible to inject fuel at the same angle as the inclination angle of the injection hole by increasing the thickness of the injection hole plate and making the injection hole longer. However, as the injection hole becomes longer, atomization deteriorates. Can be injected only at an angle less than the inclination angle of the nozzle hole. Since the inclination angle of the nozzle hole has a processing limit angle due to processing reasons, in the conventional fuel injection valve, the fuel injection angle is at most less than the processing limit angle of the injection hole. Therefore, there is a limit to the distance that the fuel injection valve can be brought close to the intake valve even if the injection hole is inclined.

Further, according to the fuel injection method described in Patent Document 3, since the intake flow control device must be provided, the cost increases. Therefore, it is desirable to prevent fuel adhesion by reducing the distance between the nozzle hole and the intake valve.
The present invention has been created in view of the above-described problems, and an object of the present invention is to provide a fuel injection valve that can optimize the injection direction even if it is disposed in the vicinity of the upstream side of the intake valve.

According to the first, second, and third aspects of the present invention, the fuel is supplied from between the first plate provided at the downstream end of the valve body in the axial direction and the second plate overlapping the downstream side of the first plate. By injecting, fuel can be injected at an angle substantially perpendicular to the valve shaft. When fuel is injected at an angle substantially perpendicular to the valve axis, even if the fuel injection valve is brought close to the intake valve, the spray does not directly collide with the vicinity of the center of the intake valve, and the optimum target position along the outer periphery of the intake valve Can be sprayed toward. Therefore, the injection direction can be optimized even if the fuel injection valve is arranged in the vicinity of the upstream side of the intake valve. As a result, the fuel adhering to the wall surface of the intake port can be reduced, and exhaust emission and deterioration of fuel consumption can be reduced.

According to the second aspect of the present invention, fuel can be injected simultaneously in two directions that are substantially perpendicular to the valve shaft and opposite to each other. Therefore, the two intake valves can be used while the fuel injection valve is close to the intake valve. Fuel can be injected with one fuel injection valve into the mouth .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 2 is a cross-sectional view of the fuel injection valve 10 according to the first embodiment of the present invention.
The valve body 11 accommodates a nozzle needle 12 as a valve member so as to be able to reciprocate. A valve seat 13 on which the nozzle needle 12 can be seated is formed on the inner peripheral wall of the valve body 11. The coupling portion 14 on the side opposite to the valve seat 13 of the nozzle needle 12 is coupled to the movable core 15 by welding or the like.

The fixed core 16 is installed on the opposite side of the movable core 15 from the nozzle needle 12 so as to face the movable core 15.
The adjusting pipe 17 is press-fitted on the inner peripheral side of the fixed core 16. A fuel passage 18 is formed on the inner peripheral side of the adjusting pipe 17.
One end of the spring 19 abuts on the adjusting pipe 17, the other end abuts on the movable core 15, and biases the movable core 15 toward the valve seat 13. The biasing force of the spring 19 is adjusted by the press-fitting amount of the adjusting pipe 17.

When energization of the coil 20 is turned on, the movable core 15 is attracted by the fixed core 16 against the urging force of the spring 19, and the nozzle needle 12 is separated from the valve seat 13. When the nozzle needle 12 is separated from the valve seat 13, fuel is injected from the nozzle hole, and when the nozzle needle 12 is seated on the valve seat 13, fuel injection from the nozzle hole is blocked.
The valve body 11 has an opening 34 (see FIG. 3A) on the downstream side, and a nozzle hole plate 21 is provided. The nozzle hole plate 21 includes a first plate 22 (see FIG. 3A) and a second plate 23 (see FIG. 3A).

3A is a cross-sectional view schematically showing the downstream side of the fuel injection valve 10, and FIG. 3B is a first plate 22 and a second plate 23 viewed from the X direction shown in FIG. 3A. It is a schematic diagram which shows. As shown in FIG. 3B, the first plate 22 is formed in a disc shape, and a rectangular opening 24 is formed in the center. The second plate 23 can be elastically deformed and is substantially rectangular and formed slightly larger than the opening 24. As shown in FIG. 3A, the second plate 23 overlaps the first plate 22 from the downstream side. Both ends of the second plate 23 in the longitudinal direction are fixed to the first plate 22 by welding, for example, and the opening 24 is closed by the second plate 23. In FIG. 3B, a shaded area 25 schematically shows a welded portion . Also, the opening 24 corresponds to the "opening" in the appended claims.

Next, the operation of the fuel injection valve 10 will be described.
1A is a cross-sectional view schematically showing the downstream side of the fuel injection valve 10, and FIG. 1B is a first plate 22 and a second plate 23 viewed from the X direction shown in FIG. It is a schematic diagram which shows. When the nozzle needle 12 is separated from the valve seat 13, the second plate 23 is pressed in the anti-X direction by the high-pressure fuel. As described above, since the second plate 23 is welded only at both ends, when pressed by high-pressure fuel, the central periphery in the longitudinal direction is elastically deformed and bent, and a gap is formed between the second plate 23 and the first plate 22. The fuel 26 is injected from the gap as shown in FIG. The fuel 26 is injected in a direction substantially perpendicular to the valve shaft P from between the first plate 22 and the second plate 23. Further, since the second plate 23 is welded only at both ends, the fuel is simultaneously injected in two directions opposite to each other as shown in the figure.

Next, the effect of the fuel injection valve 10 will be described.
FIG. 4A is a schematic diagram showing the periphery of the intake valve of the engine, and FIG. 4B is a schematic diagram showing the periphery of the intake valve from another angle. FIG. 4C is a schematic diagram showing a state where the spray is injected along the umbrella of the intake valve. Here, a case where fuel is injected during the intake stroke will be described as an example. The engine 27 has two intake ports 28 as shown in FIG. As shown in FIG. 4B, the intake port 28 is partitioned by a central partition wall 29, and two intake valves 30 that open and close the intake port for one intake port 28 are provided. One fuel injection valve 10 is provided in one intake port 28. As shown in FIG. 4A, the fuel injection valve 10 is assembled in a posture in which the valve shaft is substantially parallel to the intake flow. Since the fuel injection valve 10 can inject fuel in a direction substantially perpendicular to the valve shaft, even if the injection hole plate 21 is brought close to the central partition wall 29, the fuel injected from the fuel injection valve 10 is shown in FIG. As shown, it does not collide with the central partition wall 29. Further, as shown in FIG. 4C, the injected spray is injected toward the outer periphery of the intake valve 30, so that the spray does not directly collide with the vicinity of the center of the intake valve 30. The injected spray is sucked into the cylinder from the intake port by the intake air flow.

  According to the fuel injection valve 10 according to the first embodiment of the present invention described above, fuel can be injected in a direction substantially perpendicular to the valve shaft, so that the fuel injection valve 10 is inhaled as shown in FIG. Even if it is close to the valve 30, the spray does not directly collide with the vicinity of the center of the intake valve 30, and can be injected toward an optimum target position along the outer periphery of the intake valve 30. Therefore, even if the fuel injection valve 10 is arranged in the vicinity of the upstream side of the intake valve 30, the injection direction can be optimized. As a result, the distance from the nozzle hole plate 21 to the intake valve 30 can be shortened, and fuel adhesion to the wall surface of the intake port 28 can be reduced. As a result, the fuel adhering to the wall surface of the intake port 28 can be reduced, and exhaust emission and deterioration of fuel consumption can be reduced.

Further, according to the fuel injection valve 10, fuel can be injected by one fuel injection valve 10 into two intake ports in a state where the injection hole plate 21 is brought close to the intake valve 30.
In the first embodiment, the case where the first plate 22 is fixed to the valve body 11 has been described as an example, but the first plate 22 is not necessarily required. For example, the opening 34 may be formed in the same shape and size as the opening 24, and the opening 34 may be closed only by the second plate 23. In that case, the opening 34 corresponds to the “opening” described in the claims.

(Second embodiment)
FIG. 5 is a schematic view showing the nozzle hole plate 33 according to the second embodiment. The nozzle hole plate 33 includes a first plate 22 and a second plate 23. Three sides of the second plate 23 are welded to the first plate 22. In FIG. 5, a region 32 indicated by shading schematically shows a welded portion. Accordingly, the fuel 26 is injected only in one direction at the nozzle hole plate 33.

Next, the operation of the fuel injection valve 31 according to the second embodiment will be described.
FIG. 6A is a schematic diagram showing the periphery of the intake valve, and FIG. 6B is a schematic diagram showing the periphery of the intake valve from another angle. Here, a case where fuel is injected during the intake stroke will be described as an example. As shown in FIG. 6B, the engine 27 is provided with two intake valves 30 for one intake port 28. One fuel injection valve 31 is provided for each intake valve 30. As shown in FIG. 6A, the fuel injection valve 31 has a valve shaft assembled in a posture substantially perpendicular to the intake flow, and injects fuel in a direction substantially perpendicular to the valve shaft.

According to the fuel injection valve 31 of the second embodiment, fuel can be injected in one direction substantially perpendicular to the valve shaft. Therefore, when assembled in a posture in which the valve shaft is substantially perpendicular to the intake flow, FIG. As shown, even if the fuel injection valve 31 is brought close to the intake valve 30, the spray does not directly collide with the vicinity of the center of the intake valve 30, and can be injected toward the optimum target position along the outer periphery of the intake valve 30. Therefore, the fuel injection valve 31 can be disposed in the vicinity of the upstream side of the intake valve 30.
The second embodiment is substantially the same as the first embodiment in other points.

( First reference example )
FIG. 7A is a sectional view schematically showing the downstream side of the fuel injection valve 40 according to the first reference example , and FIG. 7B is an injection hole plate viewed from the X direction shown in FIG. FIG. Here, the X direction corresponds to the valve shaft direction. In FIG. 7B, the imaginary circle 44 shows the opening 45 formed on the downstream end face of the valve body 11 on the nozzle hole plate 41.

  As shown in FIG. 7A, a disc-shaped plate member 42 is sandwiched between the valve body 11 and the nozzle hole plate 41. A circular opening 46 is formed in the plate member 42. A virtual circle 47 indicated by a broken line in FIG. 7B indicates the position of the opening 46 of the plate member 42, and the opening 46 is formed at a position deviated from the center of the nozzle hole plate 41 as illustrated. A crescent-shaped region that is surrounded by a virtual circle 47 and not surrounded by the virtual circle 44 and a valve by interposing a plate member 42 in which an opening 46 is formed at a position offset from the center. A gap 43 is formed between the body 11 and the body 11 as shown in FIG. The gap 43 communicates with the opening 45, and part of the fuel that has passed through the opening 45 flows into the gap 43.

  A plurality of nozzle holes 49 are formed in the nozzle hole plate 41. The nozzle hole group composed of the plurality of nozzle holes 49 is arranged at a position biased with respect to the valve shaft. Specifically, all the nozzle holes 49 are formed below the openings 46 of the plate member 42. Here, the lower side means the downstream side of the fuel flow. As shown in FIG. 7B, some nozzle holes are arranged in a crescent-shaped region as viewed from the valve axis P direction. That is, it is disposed downstream of the gap 43.

  As shown in FIG. 7B, the nozzle hole 49 on one side across the virtual straight line 50 has an intersection point Q between the nozzle hole plate 41 and the valve shaft P, a position of the virtual straight line 50 0 °, and an intersection point Q. When the surrounding injection angle is θ, the fuel is injected in a direction 51 of 0 ° <θ <90 °. Conversely, the nozzle hole 49 on the other side across the virtual straight line 50 is formed so as to inject fuel in a direction 52 of −90 ° <θ <0 °. That is, the nozzle hole plate 41 can simultaneously inject fuel in two different directions.

Next, the operation of the fuel injection valve 40 will be described.
FIG. 8A is a sectional view showing the periphery of the valve seat 13 in an enlarged manner, and FIG. 8B is a sectional view showing the nozzle hole 49a in an enlarged manner. As shown in FIG. 8A, the gap 43 generates a fuel flow from the radial center to the radial direction, that is, a fuel flow 53 that flows in a direction perpendicular to the valve shaft and in the inclination direction of the nozzle hole. When a fuel flow having an angle inclined with respect to the valve shaft than the angle of inclination of the injection hole 49 flows into the injection hole 49, the atomized fuel is injected into the injection hole 49 at an angle equal to or greater than the angle of the injection hole. Can be injected with. That is, the fuel injection valve 40 can inject fuel at an angle equal to or greater than the processing limit angle of the nozzle hole 49 without deteriorating atomization by changing the angle of the fuel flow. .

Next, the effect of the fuel injection valve 40 will be described.
FIG. 9 is a schematic view around the intake valve. As with the fuel injection valve 31 of the second embodiment, the fuel injection valve 40 is assembled in a posture in which the valve shaft is substantially perpendicular to the intake air flow. Similarly, one intake port 28 includes two intake valves 30, and only one fuel injection valve 40 is provided for the two intake valves 30.

According to the fuel injection valve 40 of the first reference example , fuel can be injected at an angle equal to or greater than the processing limit angle. Therefore, when the valve shaft is assembled in a posture substantially perpendicular to the intake air flow, the fuel injection valve 40 is as shown in FIG. Even if it is close to the intake valve 30, the spray does not directly collide with the vicinity of the center of the intake valve 30, but can be injected toward an optimum target position along the outer periphery of the intake valve 30. Therefore, the fuel injection valve 40 can be arranged in the vicinity of the upstream side of the intake valve 30, and the injection direction can be optimized even if it is arranged in the vicinity of the upstream side of the intake valve.

Further, according to the fuel injection valve 40, fuel can be injected in two directions that are substantially perpendicular to the valve shaft and different from each other. Therefore, one fuel is supplied to the two intake ports while the injection hole plate 41 is close to the intake valve 30. Fuel can be injected by the injection valve 40.
The first reference example is substantially the same as the second embodiment in other points.

( Second reference example )
10A is a cross-sectional view schematically showing the downstream side of the fuel injection valve 60 according to the second reference example , and FIG. 10B is an injection hole plate viewed from the X direction shown in FIG. FIG. The nozzle hole plate 61 is fixed to the downstream side of the valve body 81 in a posture inclined with respect to a virtual plane 63 orthogonal to the valve axis P. As shown in FIG. 10B, the nozzle holes 62 are evenly arranged around the valve shaft P, and are formed so as to inject fuel in two different directions across the virtual straight line 64.

According to the fuel injection valve 60 of the second reference example , the nozzle hole plate 61 is fixed in a posture inclined with respect to the virtual plane 63, so that the nozzle hole 62 can be inclined with respect to the valve axis P by a machining angle or more. Therefore, for example, when the nozzle hole 62 is formed at the machining limit angle, it can be inclined more than the machining limit angle. Therefore, even if the nozzle hole 62 is brought close to the intake valve 30, the spray does not directly collide with the vicinity of the center of the intake valve 30 and can be injected toward an optimum target position along the outer periphery of the intake valve 30. Therefore, even if the fuel injection valve 60 is arranged in the vicinity of the upstream side of the intake valve 30, the injection direction can be optimized.

Furthermore, according to the fuel injection valve 60, since the nozzle hole plate 61 is inclined, the area in which the nozzle holes 62 can be arranged is widened. More specifically, since the width H shown in FIG. 10A is widened by inclining the nozzle hole plate 61, the area in which the nozzle holes 62 can be arranged is widened. As a result, the interval between the injection holes 62 can be widened, and deterioration of atomization due to recombination of sprays after injection can be prevented.
The second reference example is substantially the same as the first reference example in other points.

( Third reference example )
FIG. 11A is a cross-sectional view schematically showing the downstream side of the fuel injection valve 70 according to the third reference example , and FIG. 11B is an enlarged cross-sectional view showing one of the injection holes 62. . The third reference example is a modification of the second reference example . The nozzle needle 71 as a valve member has a convex portion 78 that further extends from the portion R where the nozzle needle 71 is seated on the valve seat 80 toward the nozzle hole plate 61. The tip surface 79 of the convex portion 78 is parallel to the nozzle hole plate 61, and the nozzle needle 71 rotates around the valve axis P in order to maintain the tip surface 79 of the convex portion 78 parallel to the nozzle hole plate 61. It is regulated.

Next, the operation of the fuel injection valve 70 will be described.
A fuel flow path 83 is formed by the gap 73 formed by the valve body 81 and the nozzle needle 71, the gap 74, and the tip surface 79 of the projection 78 and the injection hole plate 61. A fuel flow that flows from the upper side to the lower side in the inclination direction of the nozzle hole plate 61 is generated in the fuel flow path 83 as indicated by an arrow 75.

According to the fuel injection valve 70 of the third reference example , when the fuel flow flowing in the direction of the arrow 75 flows into the nozzle hole 62, a large pressure gradient is generated in the nozzle hole 62 on the lower side in the tilt direction and on the upper side in the tilt direction. Since the pressure portion 76 is formed, atomization can be further promoted.
In the third reference example , since the direction of the arrow 75 in which the fuel flows and the direction 77 in which the spray is injected are opposite to each other, the spray angle of the spray with respect to the valve shaft P is shallower than the inclination angle of the injection hole 62. Since the hole plate 61 itself is inclined, fuel can be injected with respect to the valve shaft P at an angle equal to or greater than the processing angle of the injection hole 62.
The third reference example is substantially the same as the second reference example in other points.

(A) is sectional drawing of the downstream of the fuel injection valve which concerns on 1st embodiment of this invention, (B) is a schematic diagram which shows the 1st plate and 2nd plate which were seen from the X direction shown to (A). Sectional drawing of the fuel injection valve which concerns on 1st embodiment of this invention. (A) is sectional drawing of the downstream of the fuel injection valve which concerns on 1st embodiment of this invention, (B) is a schematic diagram which shows the 1st plate and 2nd plate which were seen from the X direction shown to (A). (A) is a schematic diagram around the intake valve according to the first embodiment of the present invention, (B) is a schematic diagram showing a cross section around the intake valve viewed from the X direction shown in (A), and (C) is a spray. The schematic diagram which shows a mode that it injects. The schematic diagram which shows the 1st plate and 2nd plate which concern on 2nd embodiment of this invention. (A) is a schematic diagram around the intake valve according to the second embodiment of the present invention, (B) is a schematic diagram showing the periphery of the intake valve from another angle. (A) is sectional drawing of the nozzle hole periphery of the fuel injection valve which concerns on the 1st reference example of this invention, (B) is a schematic diagram which shows the nozzle hole plate seen from the X direction shown to (A). (A) is sectional drawing which expands and shows the valve seat periphery which concerns on the 1st reference example of this invention more, (B) is sectional drawing which expands and shows a nozzle hole periphery more. The schematic diagram of the intake valve periphery which concerns on the 1st reference example of this invention. (A) is sectional drawing of the nozzle hole periphery of the fuel injection valve which concerns on the 2nd reference example of this invention, (B) is a schematic diagram which shows the nozzle hole plate seen from the X direction shown to (A). (A) is sectional drawing of the nozzle hole periphery of the fuel injection valve which concerns on the 3rd reference example of this invention, (B) is sectional drawing which expands and shows one of the nozzle holes. (A) is a schematic diagram which shows the spray injected during the non-intake stroke of the conventional fuel injection valve, (B) is a schematic diagram which shows the spray injected during the intake stroke in the conventional fuel injection valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel injection valve, 11 Valve body, 12 Nozzle needle (valve member), 13 Valve seat, 23 2nd plate (plate), 24 Opening, 31 Fuel injection valve, 33 Injection hole plate, 40 Fuel injection valve, 41 Injection hole Plate, 43 Clearance, 45 Opening, 49 Injection hole, 60 Fuel injection valve, 61 Injection hole plate, 62 Injection hole, 63 Virtual plane, 70 Fuel injection valve, 71 Nozzle needle (valve member), 78 Protruding part, 79 Tip surface , 80 Valve seat, 81 Valve body

Claims (3)

A valve body which have a valve seat in the fuel passage,
A valve member housed in the valve body, allowing fuel injection by being separated from the valve seat, and blocking fuel injection by being seated on the valve seat;
A first plate provided at an end of the valve body on the downstream side in the axial direction and having an opening communicating with the axial direction;
The opening is formed larger than, and a second plate for closing said opening overlaps the downstream side of the axial direction of the first plate,
When the valve member is separated from the valve seat, the second plate is elastically deformed to the downstream side in the axial direction by the fuel pressure in the fuel passage, so that the second plate is located between the upstream wall surface and the first plate. A fuel injection valve characterized in that a gap is formed in the nozzle and fuel is injected from the gap. Both ends of the plate are fixed to the valve body,
The fuel injection valve according to claim 1, wherein fuel is injected in two directions opposite to each other.   The fuel injection valve according to claim 2, wherein the plate is formed in a substantially rectangular shape, and the both end portions in the longitudinal direction are fixed to the valve body.

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