JP2010223154A - Pintle type electromagnetic fuel injection valve - Google Patents

Abstract

To provide a pintle type electromagnetic fuel injection valve that can always stably measure the flow rate of injected fuel and can easily cope with a request for changing the flow rate of injected fuel.
In a pintle type electromagnetic fuel injection valve in which a pintle is inserted into a needle valve and penetrates into a nozzle hole through a valve hole, the pintle is connected to an outer peripheral surface thereof and a valve hole. 8 and the inner peripheral surface of the nozzle hole 10 are formed so as to expand toward the outlet of the nozzle hole 10, and when the needle valve 16 is opened, the valve portion 16a and the valve seat 7 The valve opening gap g1 is set smaller than the opposed gaps g2 and g3 between the outer peripheral surface of the pintle 17 and the inner peripheral surfaces of the valve hole 8 and the nozzle hole 10, and the valve opening gap g1 The weighing unit was determined.
[Selection] Figure 4

Description

  The present invention relates to a fuel injection valve used in a fuel supply system of an internal combustion engine, and more particularly, to a high-pressure fuel passage, a conical valve seat, a cylindrical valve hole, and an outlet sequentially connected to a downstream end of the high-pressure fuel passage. A valve housing having a conical nozzle hole that expands toward the diameter, and a needle valve that is slidably supported on the inner peripheral surface of the high-pressure fuel passage and that opens and closes the valve hole in cooperation with the valve seat And an electromagnetic actuator for opening and closing the needle valve, and a pintle type electromagnetic fuel injection valve in which a pintle penetratingly arranged in the nozzle hole through the valve hole is connected to the needle valve. Regarding improvement.

  A pintle type electromagnetic fuel injection valve is already known as disclosed in Patent Document 1 below.

  In the conventional pintle type electromagnetic fuel injection valve, as shown in FIG. 5, the main part of the pintle 017 is formed in a columnar shape, and the outer peripheral surface of this cylindrical main part and the cylindrical valve hole 08 surrounding it. The cylindrical gap g defined between the inner peripheral surface of the nozzle and the inner peripheral surface is a metering unit that determines the injected fuel flow rate when the needle valve 016 is opened.

Japanese Patent No. 2860463

  By the way, as described above, the cylindrical gap g between the outer peripheral surface of the columnar main portion of the pintle 017 and the inner periphery of the cylindrical valve hole 08 is used as a measuring portion for determining the injected fuel flow rate. Since the metering part is located downstream of the valve seat, when the needle valve 016 is opened, the high-pressure fuel that has passed through the valve seat 07 reaches a large amount of bubbles by boiling under reduced pressure while reaching the metering part. And the bubbles make measurement of the injected fuel flow rate unstable in the metering section.

  In addition, soot in the blown-back gas from the engine may adhere to and accumulate on the outer peripheral surface of the pintle 017 and the inner peripheral surface of the valve hole 08 corresponding to the measuring portion, and the gap g may be narrowed. However, this also causes the measurement of the injected fuel flow rate to be upset.

  Further, when the cylindrical gap g is changed in order to change the flow rate of the injected fuel in response to a specification change request, the outer diameter of the cylindrical main portion of the pintle 017 and the cylindrical inner peripheral surface of the valve hole 08 Therefore, it is difficult to reduce the cost.

  The present invention has been made in view of such circumstances, and can always stably measure the flow rate of the injected fuel, and can easily cope with a request for changing the flow rate of the injected fuel. An object of the present invention is to provide a pintle type electromagnetic fuel injection valve.

  In order to achieve the above object, the present invention provides a high pressure fuel passage, a conical valve seat successively connected to the downstream end of the high pressure fuel passage, a cylindrical valve hole, and a conical nozzle that expands toward the outlet. A valve housing having a hole, a needle valve which is slidably supported on the inner peripheral surface of the high-pressure fuel passage, and which opens and closes the valve hole in cooperation with the valve seat, and opens and closes the needle valve In a pintle type electromagnetic fuel injection valve comprising an electromagnetic actuator, wherein the needle valve is provided with a pintle penetratingly disposed in the nozzle hole through the valve hole. A facing gap between the valve hole and the inner peripheral surface of the nozzle hole is formed so as to expand toward the outlet of the nozzle hole, and when the needle valve is opened, a valve opening gap between the valve portion and the valve seat is formed. , The pintle and the valve hole and nozzle Is set smaller than the opposing gap between the inner peripheral surface of the the open valve clearance, the first characterized in that a weighing unit for determining the injected fuel flow rate. The electromagnetic actuator corresponds to a valve spring 22 and a coil assembly 28 in an embodiment of the present invention described later.

  Further, in addition to the first feature, the present invention is configured such that the outer peripheral surface of the pintle is configured by sequentially connecting a forward tapered surface, a reverse surface, and a reverse tapered surface from the valve portion side, As the distance from the valve portion increases, the diameter decreases until the valve hole is passed. The reverse surface is curved so as to continuously connect the forward taper surface to the reverse taper surface. The second feature is that the diameter increases toward the tip of the pintle.

  Furthermore, in addition to the second feature, the third feature of the present invention is that the axial length of the valve hole is set smaller than its diameter.

  Furthermore, in addition to any one of the first to third features, the present invention has a fourth feature in that the tip surface of the pintle is arranged inward in the axial direction from the outlet of the nozzle hole.

  Furthermore, in addition to any one of the first to fourth features, the present invention centers the outer peripheral surface of the valve portion of the needle valve on the valve seat on the axis of the needle valve. A fifth feature is that the portion is formed of a part of a spherical surface.

  According to the first feature of the present invention, when the needle valve is opened, the opening gap between the valve portion and the valve seat is determined by the opposing gap between the outer peripheral surface of the pintle and the inner peripheral surface of the valve hole and the nozzle hole. Since the metering unit that determines the injected fuel flow rate is set to a small value, the injected fuel flow rate is measured when high pressure fuel in the high pressure fuel passage comes out of the valve hole when the needle valve is opened. It is performed before boiling under reduced pressure, and is not affected by bubbles generated by the reduced pressure boiling of the high-pressure fuel, and the measurement of the injected fuel flow rate in the metering unit can be stabilized.

  Moreover, even if soot in the blown-back gas from the engine adheres to and accumulates on the outer peripheral surface of the pintle and the inner peripheral surfaces of the valve holes and nozzle holes, the deposits cause the metering part between the valve seat and the valve part, that is, the opening. The measurement of the injected fuel flow rate in the metering unit can be stabilized without being affected by the valve gap, which can contribute to the stabilization of the engine performance.

  In addition, the valve opening gap, which is the metering section between the valve seat and the valve section, can be easily adjusted by adjusting the opening stroke of the needle valve. Can respond.

  According to the second feature of the present invention, the high-pressure fuel measured by the metering unit starts boiling under reduced pressure when it comes out to the valve hole. Bubbles are generated and atomization is effectively promoted. The atomized fuel is smoothly guided by the outer peripheral surface of the pintle, that is, the forward taper surface, the reversal surface, and the reverse taper surface, thereby forming a single spray foam that diffuses into a hollow cone. Moreover, the spread angle of the hollow conical spray foam can be easily set as desired by selecting the center angle of the reverse tapered surface. At that time, the inner peripheral surface of the conical nozzle hole moves away from the reverse taper surface of the pintle toward the outlet thereof, so that it does not interfere with the formation of the hollow conical spray foam. Thus, the hollow conical spray foam having the desired spread angle can prevent fuel from adhering to the inner surface of the small-diameter intake port even in a small displacement engine, and can contribute to improvement in fuel efficiency and output performance.

  According to the third feature of the present invention, the axial length of the valve hole is set smaller than its diameter, so that when the needle valve is opened, high-pressure fuel can pass through the valve hole in a short time. As a result, it is possible to accelerate the low-pressure boiling of the high-pressure fuel in the nozzle hole and promote the atomization more effectively.

  According to the fourth aspect of the present invention, the pintle does not protrude outward from the nozzle hole, and therefore the tip of the valve housing may come into contact with other objects during the handling of the pintle type electromagnetic fuel injection valve. However, the pintle can be protected by the valve housing.

  According to the fifth feature of the present invention, even if the needle valve tilts when the valve is closed, the seating state of the valve portion on the valve seat can always be kept normal, and unnecessary use of the high-pressure fuel from the valve seat is possible. Leakage can be easily prevented.

The longitudinal cross-sectional view of the pintle type | mold electromagnetic fuel injection valve which concerns on the Example of this invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. FIG. 3 is an enlarged view of part 3 of FIG. 2 (the needle valve is closed). FIG. 4 is a diagram corresponding to FIG. 3 showing the opened state of the needle valve. The pintle peripheral part expanded sectional view of the conventional pintle type electromagnetic fuel injection valve.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  1 and 2, a valve housing 1 of a pintle type fuel injection valve I includes a cylindrical valve seat member 3 and a magnetic cylinder that is coaxially and liquid-tightly welded to the rear end of the valve seat member 3. Body 4, a non-magnetic cylindrical body 6 that is coaxially and liquid-tightly welded to the rear end of the magnetic cylindrical body 4, and a coaxial and liquid-tight fit to the inner peripheral surface of the rear end portion of the non-magnetic cylindrical body 6. The cylindrical fixed core 5 is fixed, and the fuel inlet cylinder 13 is coaxially and liquid-tightly connected to the rear end portion of the fixed core 5. A fuel filter 14 is attached to the fuel inlet cylinder 13 and a fuel conduit (not shown) for supplying high-pressure fuel from a fuel pump (not shown) is connected to the fuel inlet cylinder 13. Thus, the hollow portion from the fuel inlet cylinder 13 to the valve seat member 3 becomes the high-pressure fuel passage 2.

  As shown in FIGS. 2 and 3, the valve seat member 3 includes a conical valve seat 7 that is a downstream end of the high-pressure fuel passage 2, and a funnel-shaped fuel assembly guide hole that is continuous with the rear end of the valve seat 7. 9 and a first guide hole 12 connected to the large-diameter end of the fuel assembly guide hole 9, and the center angle of the fuel assembly guide hole 9 is set larger than the center angle of the valve seat 7.

  The valve seat member 3 is also provided with a cylindrical valve hole 8 and a conical nozzle hole 10 that are successively connected to the small diameter end of the valve seat 7, and the cylindrical valve hole 8 has an axial length h. Is smaller than the diameter d (see FIG. 3).

  As shown in FIG. 2, the hollow portion of the magnetic cylindrical body 4 is a second guide hole 12 ′ having a larger diameter than the first guide hole 12. A portion that does not fit with the fixed core 5 remains at the front end portion of the nonmagnetic cylindrical body 6, and the valve core assembly V is accommodated in the valve housing 1 that extends from the portion to the valve seat member 3. The valve core assembly V is slidably fitted into the first guide hole 12 and is integrated with a needle valve 16 that opens and closes the valve hole 8 in cooperation with the valve seat 7 and a rear end of the needle valve 16. And a movable core 15 that is slidably fitted into the second guide hole 12 ′ and faces the front end surface of the fixed core 5.

  A plurality of notches 26 that allow fuel flow in the high-pressure fuel passage 2 are provided in the bowl-shaped journal portion 25 slidably fitted into the first guide hole 12 of the needle valve 16. Further, the outer peripheral surface of the valve portion 16 a that can be seated on the valve seat 7 of the needle valve 16 is formed by a part of the spherical surface S having the center C on the axis Y of the needle valve 16.

  A pintle 17 penetratingly arranged in the nozzle hole 10 through the valve hole 8 is integrally connected to the valve portion 16a. The outer peripheral surface of the pintle 17 is formed by sequentially connecting a forward tapered surface 17a, a reversing surface 17b, and a reverse tapered surface 17c in order from the valve portion 16a side. The forward tapered surface 17a becomes a valve hole 8 as the distance from the valve portion 16a increases. The reversing surface 17b is curved so as to continuously connect the forward tapered surface 17a to the reverse tapered surface 17c. The reverse tapered surface 17c is pintle 17 in the nozzle hole 10. It has a shape that increases in diameter toward the tip, and the tip surface of the reverse tapered surface 17 c, that is, the tip surface of the pintle 17, is arranged axially inward from the outlet of the nozzle hole 10. The central angle α of the reverse tapered surface 17c is set smaller than the central angle β of the nozzle hole 10 on the cone. Thus, as shown in FIG. 4, the facing gap g <b> 2 between the outer peripheral surface of the pintle 17 and the inner peripheral surfaces of the valve hole 8 and the nozzle hole 10 is enlarged toward the outlet of the nozzle hole 10. Moreover, the expansion rate of the facing gap g3 between the outer peripheral surface of the pintle 17 and the inner peripheral surface of the nozzle hole 10 is larger than the expansion rate of the opposing gap g2 between the outer peripheral surface of the pintle 17 and the inner peripheral surface of the valve hole 8. Yes.

  As shown in FIG. 4, when the needle valve 16 is opened, the valve opening gap g1 between the valve portion 16a and the valve seat 7 is the outer peripheral surface of the pintle 17 and the inner peripheral surfaces of the valve hole 8 and the nozzle hole 10. Is set smaller than the opposed gaps g2 and g3, and the valve opening gap g1 serves as a metering unit for determining the injected fuel flow rate.

  1 and 2 again, the valve core assembly V has a vertical hole 19 that ends from the rear end surface of the movable core 15 in front of the valve portion 16a, and the vertical hole 19 communicates with the outer peripheral surface of the needle valve 16. And a plurality of lateral holes 20 are provided. In the middle of the vertical hole 19, a spring seat 24 made of a step portion on the inner peripheral surface of the movable core 15 is provided. The vertical hole 19 communicates with the hollow portion of the fixed core 5.

  A pipe-shaped retainer 23 is fitted and fixed in the hollow portion of the fixed core 5. The valve core assembly V is urged toward the valve seat 7 between the retainer 23 and the spring seat 24. The valve spring 22 is contracted.

  A hard, non-magnetic cylindrical stopper member 18 is fixed to the inner peripheral surface of the movable core 15 so as to surround the valve spring 22. The stopper member 18 has its outer end slightly protruding from the rear end suction surface of the movable core 15, and normally there is a gap corresponding to the valve opening stroke of the valve core assembly V, and the front end of the fixed core 5. Opposed to the suction surface.

  A coil assembly 28 is fitted on the outer periphery of the valve housing 1. The coil assembly 28 includes a bobbin 29 fitted to the outer peripheral surface from the magnetic cylinder 4 to the nonmagnetic cylinder 6 and the fixed core 5, and a coil 30 wound around the bobbin 29. A cylindrical coil housing 31 that houses the assembly 28 is integrally connected to the magnetic cylinder 4. A yoke 35 is press-fitted and fixed between the open rear end of the coil housing 31 and the fixed core 5.

  A hard synthetic resin coating 32 is formed on the outer peripheral surface of the coil housing 31 from the latter half of the coil housing 31 to the fuel inlet cylinder 13. At that time, the synthetic resin is also filled in the coil housing 31 to embed the coil assembly 28. Further, a coupler 34 protruding in one side is integrally formed in the intermediate portion of the covering body 32, and the coupler 34 holds a power feeding terminal 33 that is continuous with the coil 30.

  Next, the operation of this embodiment will be described.

  In the state where the coil 30 is demagnetized, the valve core assembly V is pressed forward by the urging force of the valve spring 22, and the needle valve 16 is seated on the valve seat 7 (see FIG. 3). In this valve-closed state, the fuel pressure-fed from a fuel pump (not shown) to the fuel inlet cylinder 13 stands by in the high-pressure fuel passage 2 in the valve housing 1.

  Now, when the coil 30 is energized by energization, the magnetic flux generated thereby passes from the fixed core 5 to the movable core 15 through the yoke 35, the coil housing 31 and the magnetic cylindrical body 4, while bypassing the nonmagnetic cylindrical body 6, and to the fixed core. 5, the movable core 15 is attracted to the fixed core 5 against the set load of the valve spring 22 by the magnetic force generated thereby, and the needle valve 16 is separated from the valve seat 7 (see FIG. 4). Therefore, the high-pressure fuel that has been waiting in the high-pressure fuel passage 2 of the valve housing 1 proceeds to the valve seat 7 along the fuel assembly guide hole 9, and the valve portion 16a of the needle valve 16 and the valve opening gap g1, That is, after the flow rate is measured by the measuring section, it comes out to the valve hole 8 and starts boiling under reduced pressure. Therefore, the injection fuel flow rate is measured before the high pressure fuel is boiled under reduced pressure, and is not affected by bubbles generated by the low pressure boiling of the high pressure fuel. It can be stabilized.

  Moreover, even if soot D in the blown-back gas from the engine adheres to and accumulates on the outer peripheral surface of the pintle 17 and the inner peripheral surfaces of the valve hole 8 and the nozzle hole 10, the deposits cause a gap between the valve seat 7 and the valve portion 16 a. The metering unit, that is, the valve opening gap g1, is not affected, and the metering of the injected fuel flow rate in the metering unit can be stabilized, which can contribute to the stabilization of the engine performance.

  Further, the valve opening gap g1 serving as a metering portion between the valve seat 7 and the valve portion 16a can be easily adjusted by adjusting the valve opening stroke of the needle valve 16, and by this adjustment, a change request for the injected fuel flow rate is required. Can be easily dealt with. Specifically, for example, the amount of protrusion of the nonmagnetic cylindrical stopper member 18 fitted and fixed to the inner peripheral surface of the movable core 15 is set to a large value in advance, and in response to a request to change the injected fuel flow rate. Thus, the valve opening gap g1 between the valve seat 7 and the valve portion 16a can be easily adjusted by appropriately reducing the protruding amount of the stopper member 18 by cutting. Therefore, it is not necessary to create new parts, which can contribute to cost reduction.

  Further, the axial length h of the valve hole 8 is set to be smaller than its diameter d, so that when the needle valve 16 is opened, high-pressure fuel can pass through the valve hole 8 in a short time. The low-pressure boiling of the high-pressure fuel in the nozzle hole 10 can be accelerated, and the atomization can be promoted more effectively.

  The atomized fuel that has moved from the valve hole 8 to the nozzle hole 10 is diffused into a hollow cone by being smoothly guided by the forward tapered surface 17a, the reverse surface 17b, and the reverse tapered surface 17c on the outer peripheral surface of the pintle 17. A single spray form F is formed. Moreover, the spread angle of the hollow conical spray foam F can be easily set as desired by selecting the center angle α of the reverse tapered surface 17c. At this time, the inner peripheral surface of the conical nozzle hole 10 moves away from the reverse tapered surface 17c of the pintle 17 toward the outlet thereof, and therefore does not interfere with the formation of the hollow conical spray form F.

  Since the hollow conical spray form F having a desired spread angle can be obtained in this way, when this pintle type electromagnetic fuel injection valve I is employed in a small displacement engine, an intake port with a small diameter of the injected fuel is used. It can prevent adhesion to the inner surface and can contribute to improved fuel efficiency and output performance.

  Further, since the front end surface of the pintle 17 is disposed inward in the axial direction from the outlet end of the nozzle hole 10, the pintle 17 does not protrude outward from the nozzle hole 10, and therefore the pintle type electromagnetic fuel injection valve During handling of I, the pintle 17 can be protected by the valve housing 1 even if the tip of the valve housing 1 may come into contact with another object.

  Further, the outer peripheral surface of the valve portion 16a seated on the valve seat 7 of the needle valve 16 is formed by a part of the spherical surface S having the center C on the axis Y of the needle valve 16, so that the needle valve 16 Even when the valve is tilted when the valve is closed, the seating state of the valve portion 16a on the valve seat 7 can always be kept normal, and unnecessary leakage of the high-pressure fuel from the valve seat 7 can be easily prevented.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention.

I ... Electromagnetic fuel injection valve 2 ... High pressure fuel passage 7 ... Valve seat 8 ... Valve hole 10 ... Nozzle hole 16 ... Needle valve 17 ... Pintle 17a ... Forward taper surface 17b ... Reversing surface 17c ... Reverse taper surface 22, 28 ... ... Electromagnetic actuator (valve spring, coil assembly)
g1... Valve opening gap g2... Opposing gap g3... Opposing gap d ... Valve hole diameter h ... Valve hole axial length S ...・ Spherical surface C ... Spherical center Y ... Needle valve axis

Claims (5)

A high pressure fuel passage (2), a conical valve seat (7) successively connected to the downstream end of the high pressure fuel passage (2), a cylindrical valve hole (8), and a conical nozzle that expands toward the outlet A valve housing (1) having a hole (10) and a slidably supported on the inner peripheral surface of the high-pressure fuel passage (2), and in cooperation with the valve seat (7), the valve hole (8 ) And a solenoid valve (16) having a valve portion (16a) for opening and closing, and an electromagnetic actuator (22, 28) for opening and closing the needle valve (16). The needle valve (16) includes the valve In a pintle type electromagnetic fuel injection valve in which a pintle (17) is provided continuously through the hole (8) and inserted into the nozzle hole (10), the pintle (17) is connected to the outer peripheral surface and the valve. Opposing gaps (g2, g) between the hole (8) and the inner peripheral surface of the nozzle hole (10) 3) is formed so as to expand toward the outlet of the nozzle hole (10),
When the needle valve (16) is opened, the valve-opening gap (g1) between the valve portion (16a) and the valve seat (7) is separated from the outer peripheral surface of the pintle (17), the valve hole (8) and the nozzle. A pintle characterized in that it is set smaller than the opposing gaps (g2, g3) between the inner peripheral surface of the hole (10) and the valve-opening gap (g1) is used as a metering unit for determining the injected fuel flow rate. Type electromagnetic fuel injection valve. The pintle type electromagnetic fuel injection valve according to claim 1,
An outer peripheral surface of the pintle (17) is constituted by sequentially connecting a forward tapered surface (17a), a reverse surface (17b), and a reverse tapered surface (17c) from the valve portion (16a) side, and the forward tapered surface (17a ) Has a shape that decreases in diameter until it passes the valve hole (8) as it moves away from the valve portion (16a), and the reverse surface (17b) is continuous with the forward tapered surface (17a) and the reverse tapered surface (17c). The pintle electromagnetic fuel injection is characterized in that the reverse tapered surface (17c) has a shape that expands toward the tip of the pintle (17) in the nozzle hole (10). valve. The pintle type electromagnetic fuel injection valve according to claim 2,
A pintle type electromagnetic fuel injection valve characterized in that the axial length (h) of the valve hole (8) is set smaller than its diameter (d). In the pintle type electromagnetic fuel injection valve according to any one of claims 1 to 3,
A pintle type electromagnetic fuel injection valve characterized in that the front end surface of the pintle (17) is disposed axially inward from the outlet of the nozzle hole (10). In the pintle type electromagnetic fuel injection valve according to any one of claims 1 to 4,
A spherical surface (S) of the outer peripheral surface of the valve portion (16a) seated on the valve seat (7) of the needle valve (16) is placed on the axis (Y) of the needle valve (16) (S). ), A pintle type electromagnetic fuel injection valve.

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