JP6224754B2 - Electromagnetic fuel injection valve for in-cylinder injection - Google Patents

Description

  The present invention relates to an in-cylinder injection electromagnetic fuel injection valve mainly used in a fuel supply system of an internal combustion engine, and in particular, has a valve seat and a plurality of annularly arranged fuel injection holes. The present invention relates to an improvement in an in-cylinder injection electromagnetic fuel injection valve that includes a valve seat member that injects fuel and a valve body that opens and closes the fuel injection hole in cooperation with the valve seat.

  Such an in-cylinder injection electromagnetic fuel injection valve is already known as disclosed in Patent Document 1 below.

JP 2005-13989 A

  In the in-cylinder injection electromagnetic fuel injection valve described in Patent Document 1, a single injector has a first injection hole forming a first angle and a second angle larger than the first angle. A second nozzle hole having a penetrating force smaller than that of the first nozzle hole, and at the time of stratified combustion, the spray is concentrated around the spark plug through the cavity while the second nozzle is used at the time of diffusion combustion. By diffusing the spray from the nozzle hole to the entire combustion chamber, the stratification of the air-fuel mixture during stratified combustion and the homogenization of the air-fuel mixture during diffusion combustion are compatible.

  In this case, the hole diameter of the nozzle hole is reduced in order to reduce the penetrating force of the second nozzle hole more than the penetrating force of the first nozzle hole, but the flow rate decreases when the hole diameter of the nozzle hole is reduced. Therefore, it is difficult to secure a flow rate of a certain level while reducing the penetration force, and there is a possibility that a situation that does not match the actual situation in recent years where various combustion forms and spray forms are required may occur.

  The present invention has been made in view of such circumstances, and provides an in-cylinder injection electromagnetic fuel injection valve capable of ensuring a necessary flow rate even when penetrating force is reduced. For the purpose.

In order to achieve the above object, the present invention provides a valve seat and a valve seat member having a plurality of fuel injection holes arranged annularly in the vicinity of the valve seat and injecting fuel from the fuel injection holes, and the valve In the in-cylinder injection electromagnetic fuel injection valve including a valve body that opens and closes the fuel injection hole in cooperation with a seat, all the fuel injection holes are long holes having a long axis and a short axis. , the long axis is curved in an arc shape that both longitudinal ends toward the center of the pitch circle of the inlet of the fuel injection hole, the radius of the long axis, the radius of the front Kipi pitch circle rather smaller than, a downstream end of the fuel injection hole, the first, characterized in that opening into the bottom surface of the recess formed in the valve seat member.

  According to the present invention, in addition to the first feature, the fuel injection hole includes a large-diameter wall having a radius larger than the radius of the major axis, a small-diameter wall having a radius smaller than the radius of the major axis, A second feature is that it is composed of a connecting wall connecting the diameter wall and the small diameter wall.

  Furthermore, in addition to the second feature, the third feature of the present invention is that a virtual circle constituting the large-diameter wall and a virtual circle constituting the small-diameter wall have the same center.

  Furthermore, in addition to any one of the first to third features, the present invention is characterized in that the inlets of all the fuel injection holes are arranged on a single pitch circle.

  According to the first feature of the present invention, the fuel injection hole is a long hole having a major axis and a minor axis, and the major axis is curved in an arc shape, and the radius of the major axis is the inlet of the fuel injection hole. Since it is smaller than the radius of the pitch circle, the inner peripheral wall of the fuel injection hole is also curved with a radius smaller than the radius of the pitch circle. Therefore, the injected fuel moves along the inner peripheral wall of the curved fuel injection hole, and turbulent flow is generated so as to vortex inside the fuel injection hole. Therefore, the penetration force is reduced by the generated turbulent flow. And this reduction of penetration force is not performed by reducing the diameter of the fuel injection hole, but by changing the shape of the fuel injection hole, even if the major axis and the minor axis are enlarged to ensure the flow rate, The penetrating force can be reduced by the generated turbulent flow.

Moreover, since the downstream end of the fuel injection hole is open to the bottom surface of the recess formed in the valve seat member, the downstream end of the fuel injection hole can be protected from contact with other members.

  According to the second feature of the present invention, the fuel injection hole has a large-diameter wall having a radius larger than the radius of the long axis, a small-diameter wall having a radius smaller than the radius of the long-axis, and the large-diameter wall and the small-diameter wall. Therefore, the fuel can easily enter the fuel injection hole from the large-diameter wall side having a small curvature, and difficult to enter from the small-diameter wall side having a large curvature. Therefore, since the fuel with different motion collides in the fuel nozzle hole, it is possible to generate a larger turbulent flow, so that the penetration force can be further reduced.

  According to the third feature of the present invention, since the virtual circle constituting the large-diameter wall and the virtual circle constituting the small-diameter wall have the same center, the length of the short axis is in the circumferential direction of the fuel injection hole. It becomes constant and management of the injection flow rate becomes easy.

  According to the fourth feature of the present invention, since the inlets of all the fuel injection holes are arranged on a single pitch circle, the penetration force and the injection flow rate of the fuel injected from each fuel injection hole can be equalized. .

1 is a longitudinal side view of an in-cylinder injection electromagnetic fuel injection valve according to an embodiment of the present invention. The expanded sectional view of the valve seat member of FIG. FIG. 3 is a view taken along arrow 3-3 in FIG. 2.

  In FIG. 1, the cylinder head E of the engine is provided with a mounting hole Eb that opens to the combustion chamber Ea, and the in-cylinder injection electromagnetic fuel injection valve I is mounted in the mounting hole Eb. The fuel injection valve I can inject fuel toward the combustion chamber Ea. In the fuel injection valve I, the fuel injection side is the front and the fuel inflow side is the rear.

  A valve housing 1 of the fuel injection valve I includes a hollow cylindrical valve housing body 2, a bottomed cylindrical valve seat member 3 fitted and welded to the inner peripheral surface of the front end portion of the valve housing body 2, The magnetic cylinder 4 is fitted to the outer periphery of the large-diameter portion 2a at the rear end of the valve housing body 2 and welded thereto, and the non-magnetic cylinder 5 is coaxially coupled to the rear end of the magnetic cylinder 4. The A fixed core 6 is coaxially coupled to the rear end of the nonmagnetic cylindrical body 5, and a fuel inlet cylinder 7 is coaxially and continuously connected to the rear end of the fixed core 6. The fixed core 6 has a hollow portion 6 a communicating with the inside of the fuel inlet cylinder 7.

  The magnetic cylindrical body 4 integrally has a flange-like yoke portion 4a at an axially intermediate portion, and this yoke portion 4a surrounds the upper end opening of the mounting hole Eb of the cylinder head E. The fuel filter 8 is attached to the inlet of the fuel inlet cylinder 7.

  2 and 3, the bottomed cylindrical valve seat member 3 has a conical valve seat 9 on the front end wall 3a thereof, and is annularly arranged so as to open near the center of the valve seat 9. A plurality of fuel injection holes 10.

All the fuel injection holes 10 are long holes having a major axis 11 and a minor axis 12, and the major axis 11 has its both longitudinal ends directed toward the center O side of the pitch circle P at the inlet of the fuel injection hole 10. Are curved in an arc. Further, the inlets of the fuel injection holes 10 are arranged at equal intervals on one pitch circle P, and the radius R1 of the long axis 11 is smaller than the radius R2 of the pitch circle P. The inlets of the fuel injection holes 10 may be arranged separately on a plurality of pitch circles P, and the intervals may not be equal.

  The short axis 12 of the fuel injection hole 10 is arranged along a straight line extending in the radial direction from the center O of the pitch circle P. The long axis 11 of the fuel injection hole 10 and the pitch circle P are the fuel injection hole 10. It touches at the center position. It is also possible to arrange the minor axis 12 so as to be inclined with respect to the straight line. In this case, the inclination angles of the minor axis 12 with respect to the straight line are all the same, but are different from each other. May be.

  The fuel injection hole 10 includes a large-diameter wall 10a having a radius R3 larger than the radius R1 of the long axis 11, a small-diameter wall 10b having a radius R4 smaller than the radius R1 of the long-axis 11, and the large-diameter wall 10a and the small-diameter wall 10b. The virtual circle A constituting the large-diameter wall 10a and the virtual circle B constituting the small-diameter wall 10b have the same center O ′, but these circles A, The center of B may be at a different position.

  A recess 13 having a bottom surface 14 perpendicular to the axis l of the fuel injection hole 10 is formed on the front end wall 3 a of the valve seat member 3 from the front side, and the downstream end of the fuel injection hole 10 is formed on the bottom surface 14 of the recess 13. Open.

  A valve assembly 17 including a valve body 15 and a movable core 16 is accommodated in the valve housing 1 extending from the valve seat member 3 to the nonmagnetic cylindrical body 5. The valve body 15 includes a spherical valve portion 15 a that opens and closes the fuel injection hole 10 in cooperation with the valve seat 9, and a valve rod 15 b that supports the valve portion 15 a and extends to the hollow portion 6 a of the fixed core 6. It consists of. The valve portion 15a is formed in a spherical shape so as to be slidably supported on the inner peripheral surface of the valve seat member 3, and a plurality of flat portions that allow fuel to flow are provided on the outer peripheral surface. Further, a fuel passage 16a through which fuel flows is also provided in the intermediate portion in the radial direction of the movable core 16.

  A cylindrical guide bush 18 is press-fitted into the inner peripheral surface of the fixed core 6. At this time, the guide bush 18 is disposed such that its front end portion slightly protrudes from the front end surface of the fixed core 6, that is, the suction surface 6 b.

  A sliding member 19 slidably fitted to the inner peripheral surface of the guide bush 18 and a stopper member 20 disposed between the movable core 16 and the valve portion 15a are welded to the valve rod 15b. The sliding member 19 is disposed so that its lower end surface protrudes from the lower end surface of the guide bush 18 at the valve closing position of the valve body 15. The movable core 16 facing the suction surface 6b of the fixed core 6 is slidably fitted to the valve rod 15b so that it can move a limited stroke between the sliding member 19 and the stopper member 20. The

  The guide bush 18 and the sliding member 19 are made of a nonmagnetic or weak magnetic material having a higher hardness than the fixed core 6, for example, martensitic stainless steel. Therefore, the hardness of the guide bush 18 and the sliding member 19 is made substantially equal.

  A pipe-like retainer 21 is fitted into the hollow portion 6a of the fixed core 6 and fixed by caulking, and the valve element 15 is seated on the valve seat 9 between the retainer 21 and the sliding member 19, that is, the valve is closed. A valve spring 22 that biases in the direction is retracted. At that time, the set load of the valve spring 22 is adjusted by the insertion depth of the retainer 21 into the fixed core 6. Since the sliding member 19 is harder than the fixed core 6 as described above, the portion serving as the spring seat of the valve spring 22 has high wear resistance.

  Further, an auxiliary spring 23 is contracted between the sliding member 19 and the movable core 16, and the auxiliary spring 23 causes the sliding member 19 and the movable core 16 to move with a set load smaller than the set load of the valve spring 22. Acts to separate.

  The rear end portion of the valve rod 15b protrudes from the rear end surface of the sliding member 19, is fitted to the inner peripheral surface of the movable end portion of the valve spring 22, plays a role of positioning, and the sliding member 19 It is fitted to the inner peripheral surface of the auxiliary spring 23 and plays the role of positioning. A plurality of notches serving as fuel flow paths are provided on the outer periphery of the sliding member 19.

  A coil assembly 24 is fitted on the outer peripheral surface from the rear end portion of the magnetic cylindrical body 4 to the fixed core 6. The coil assembly 24 includes a bobbin 25 fitted to the outer peripheral surface and a coil 26 wound around the bobbin 25, and a front end portion of a coil housing 27 that houses the coil assembly 24 is a magnetic cylindrical body. 4 is placed on the yoke 4a and welded.

  A covering layer 28 made of synthetic resin is molded from the rear end portion of the coil housing 27 to the rear end portion of the fixed core 6 so as to cover the outer peripheral surfaces thereof. A coupler 29 extending to one side of the fixed core 6 is integrally connected to the covering layer 28, and the terminal 30 connected to the coil 26 is held by the coupler 29.

  Next, the operation of this embodiment will be described.

  In the non-energized state of the coil 26, the valve body 15 is pressed forward by the set load of the valve spring 22 and is seated on the valve seat 9 to close the fuel injection hole 10. That is, the movable core 16 is in a closed state, and a predetermined gap is maintained between the movable core 16 and the front end of the guide bush 18 protruding from the suction surface 6 b of the fixed core 6.

  When the coil 26 is energized, the magnetic flux generated thereby sequentially travels through the fixed core 6, the coil housing 27, the magnetic cylindrical body 4, and the movable core 16, and by this magnetic force, the movable core 16 is first attracted to the fixed core 6 and the auxiliary spring 23. Is brought into contact with the front end of the sliding member 19 while being compressed. At this time, the movable core 16 abuts against the sliding member 19 while rising and accelerating against the weak set load of the auxiliary spring 23, and promptly moves the sliding member 19 backward against the set load of the valve spring 22. It pushes up and collides with the front end of the guide bush 18 and stops. Meanwhile, the sliding member 19 pushed upward is accompanied by the valve rod 15b integrated therewith, so that the valve opening response of the valve body 15 is enhanced.

  The movable core 16 abuts against the front end of the guide bush 18 while pushing up the sliding member 19, whereby the valve body 15 is held at a predetermined valve opening position.

  When the valve body 15 is opened, the high-pressure fuel pumped from the fuel distribution pipe (not shown) to the fuel inlet cylinder 7 is inside the pipe-shaped retainer 21, the hollow portion 6 a of the fixed core 6, and the notch of the sliding member 19. The fuel passage 16a of the movable core 16, the inside of the valve housing 1, and the valve seat 9 are sequentially injected from the fuel injection hole 10 into the combustion chamber Ea of the engine.

At this time, all the fuel injection holes 10 are long holes having a major axis 11 and a minor axis 12, and the major axis 11 has both longitudinal ends at the center O of the pitch circle P at the inlet of the fuel injection hole 10. towards the side is curved in an arc shape, because the radius of the major axis 11 is smaller than the radius of the pitch circle P, the inner peripheral wall 10a of the fuel injection hole 10, 10b is also curved with a radius smaller than the radius of the pitch circle Will do. Therefore, the injected fuel moves along the inner peripheral walls 10a to 10c of the curved fuel injection hole 10, and a turbulent flow is generated so as to make a vortex inside the fuel injection hole 10. Therefore, the penetration force is generated by the generated turbulent flow. Is reduced. The penetration force is not reduced by reducing the diameter of the fuel injection hole 10, but by changing the shape of the fuel injection hole 10. Therefore, the dimensions of the long axis 11 and the short axis 12 are enlarged to secure the flow rate. Even in this case, the penetration force can be reduced by the generated turbulent flow.

  Particularly in this embodiment, the fuel injection hole 10 has a large-diameter wall 10a having a radius larger than the radius of the long axis 11, a small-diameter wall 10b having a radius smaller than the radius of the long axis 11, and the large-diameter wall 10a and Since the connecting wall 10c is connected to the small-diameter wall 10b, the fuel can easily enter the fuel injection hole 10 from the large-diameter wall 10a side having a small curvature, and is difficult to enter from the small-diameter wall 10b side having a large curvature. Become. For this reason, the fuel having different motion collides in the fuel injection hole 10, so that a larger turbulent flow can be generated and the penetration force can be further reduced.

  Moreover, since the virtual circle A constituting the large-diameter wall 10a and the virtual circle B constituting the small-diameter wall 10b have the same center O ′, the length of the short axis 12 is constant in the circumferential direction of the fuel injection hole 10. Thus, the injection flow rate can be easily managed, and the inlets of the plurality of fuel injection holes 10 are arranged on a single pitch circle P. Therefore, the penetration force and injection of the fuel injected from each fuel injection hole 10 The flow rate can be equalized.

  Furthermore, a recess 13 having a bottom surface 14 perpendicular to the axis l of the fuel injection hole 10 is formed in the front end wall 3a of the valve seat member 3 from the front, and the fuel injection hole 10 is formed in the bottom surface 14 of the recess 13. Therefore, the downstream end of the fuel injection hole 10 can be protected from contact with other members.

The present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the gist thereof. For example, although the movable core 16 is movable between the sliding member 19 and the stopper member 20 in the above embodiment, the movable core 16 can be fixed to the valve rod 15b .

3 ... Valve seat member 9 ... Valve seat 10 ... Fuel injection hole 10a ... Large diameter wall 10b ... Small diameter wall 10c ... Connection wall 11... Long axis 12... Short axis 15... Valve body A... Virtual circle B constituting a large diameter wall. Imaginary circle O '... center P of both imaginary circles ... pitch circle R1 ... radius of major axis R2 ... radius of pitch circle R3 ... Radius of large diameter wall R4 ... Radius of small diameter wall

Claims (4)

A valve seat (9) and a valve seat member (3) having a plurality of fuel injection holes (10) arranged annularly in the vicinity of the valve seat (9) and injecting fuel from the fuel injection holes (10); In-cylinder injection electromagnetic fuel injection valve comprising a valve body (15) for opening and closing the fuel injection hole (10) in cooperation with the valve seat (9),
All the fuel injection holes (10) are long holes having a major axis (11) and a minor axis (12), and the major axis (11) has both end portions in the longitudinal direction at the fuel injection holes (10). entrance of the pitch circle of) (is curved in an arc shape toward the center (O) side of the P), a radius (R1) of the long axis (11), the radius of the front Kipi pitch yen (P) rather smaller than (R2),
An in-cylinder injection electromagnetic fuel injection valve characterized in that the downstream end of the fuel injection hole (10) opens at the bottom of a recess (13) formed in the valve seat member (3) .   The fuel injection hole (10) has a large-diameter wall (10a) having a radius (R3) larger than the radius (R1) of the long axis (11) and a radius (R1) of the long axis (11). The in-cylinder assembly according to claim 1, comprising a small-diameter wall (10b) having a radius (R4) and a connecting wall (10c) connecting the large-diameter wall (10a) and the small-diameter wall (10b). Electromagnetic fuel injection valve for injection.   The virtual circle (A) constituting the large diameter wall (10a) and the virtual circle (B) constituting the small diameter wall (10b) have the same center (O '). The in-cylinder injecting electromagnetic fuel injection valve.   The in-cylinder injection electromagnetic according to any one of claims 1 to 3, wherein the inlets of all the fuel injection holes (10) are arranged on a single pitch circle (P). Fuel injection valve.

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