JP6224753B2 - 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 is intended for in-cylinder injection so that a necessary flow rate can be ensured even when penetrating force is reduced, and the amount of fuel peeling is small. An object is to provide an electromagnetic fuel injection valve.

In order to achieve the above object, the present invention has a valve seat and a valve seat member which has a plurality of fuel injection holes arranged in an annular shape and injects fuel from the fuel injection hole, and cooperates with the valve seat. In the in-cylinder electromagnetic fuel injection valve having a valve body for opening and closing the fuel injection hole, the fuel injection hole is a long hole having a major axis and a minor axis, and the major axis is an arc shape. And the radius of the major axis is smaller than the radius of the pitch circle at the inlet of the fuel nozzle hole, and all the fuel nozzle holes extend from the center of the pitch circle to the major axis and the minor axis. to a straight line extending radially towards the intersection, the minor axis is inclined to the same side, one of the two intersections of the inner peripheral wall thereof fuel injection hole and the long axis, the pitch circle It is the 1st characteristic that it exists in the diameter direction outside .

Is found in or present invention, in addition to the first feature, the inlet of all of the fuel injection hole, the second being disposed on a single of the 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, all of the fuel injection hole, because one of the two intersections with it these inner circumferential wall and the major axis located radially outward of the pitch circle, the distance from the center of the valve seat member to the fuel injection hole Even if there is a portion of the valve seat member where the fuel is likely to be separated from the wall surface of the fuel injection hole due to the inclination angle of the fuel injection hole with respect to the valve seat member, all the fuel injection holes are located radially outside the pitch circle. By extending over the inside, it is possible to keep the separation point at a part of the fuel injection hole and reduce the variation in the amount of separation. Moreover, since the nozzle hole dimension toward the radially outer side of the pitch circle can be secured, the movement of the fuel to the outside can be promoted.

In addition , when the fuel injection hole is formed by laser processing, when the inclination angle of the fuel injection hole with respect to the valve seat member is directed outward, the valve seat is formed to avoid interference between the laser beam and the cylindrical portion of the valve seat member. Although it is necessary to install an interference prevention member on the inner surface of the cylindrical part of the member, in all fuel injection holes, the injection hole size toward the radially outer side of the pitch circle can be secured, and the movement of the fuel to the outside is effective. Therefore, it becomes possible to inject fuel to the outside without directing the inclination angle of the fuel injection hole with respect to the valve seat member to the outside, and interference between the laser beam and the cylindrical portion of the valve seat member is unlikely to occur. And the installation of the interference preventing member can be omitted.

Furthermore , since all the fuel injection holes are inclined on the same side with respect to a straight line extending in the radial direction from the center of the pitch circle toward the intersection of the long axis and the short axis , It becomes easy to equalize the spray length, and management of the injection flow rate becomes easy.

According to the second feature of the present invention, since the inlets of all the fuel injection holes are arranged on a single pitch circle, it is easy to equalize the injection flow rate and the spray length, thereby facilitating the management of the injection flow rate. Become.

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.

  The fuel injection hole 10 is a long hole having a long axis 11 and a short axis 12, and the long axis 11 is curved in an arc shape. 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.

Minor axis 12 of the fuel injection hole 10, to the straight line extending in a radial direction from the center O of the pitch circle P at the intersection of the major axis 11 and minor axis 12, are inclined all in the same direction, the fuel injection orifice One of the two intersections A and B of the ten inner peripheral walls 13 and the long axis 11 is located outside the pitch circle P in the radial direction.

  The inner peripheral wall 13 of the fuel injection hole 10 has a large-diameter wall 13a having a radius R3 larger than the radius R1 of the major axis 11, a small-diameter wall 13b having a radius R4 smaller than the radius R1 of the major axis 11, and these large-diameter walls 13a. The imaginary circle K1 constituting the large-diameter wall 13a and the imaginary circle K2 constituting the small-diameter wall 13b have the same center O ′.

Note that the inlets of the fuel injection holes 10 may be arranged on a plurality of pitch circles P, and the intervals may not be equal . Also the center of the virtual circle K1, K2 may be different positions from each other.

  A recess 14 having a bottom surface 14a passing through the axis l of the fuel injection hole 10 is formed on the front end wall 3a of the valve seat member 3 from the front side, and a downstream end of the fuel injection hole 10 is opened on the bottom surface 14a of the recess 14. To do. The fuel injection hole 10 is formed at a position where its axis 1 does not intersect with the rear end of the cylindrical portion 3 b of the valve seat member 3.

  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, the fuel injection hole 10 is a long hole having a major axis 11 and a minor axis 12, and the major axis 11 is curved in an arc shape, and the radius of the major axis 11 is the pitch of the inlet of the fuel injection hole 10. Since it is smaller than the radius of the circle P, the inner peripheral wall 13 of the fuel injection hole 10 is also curved with a radius smaller than the radius of the pitch circle. Therefore, the injected fuel moves along the inner peripheral wall 13 of the curved fuel injection hole 10, and turbulent flow is generated so as to vortex inside the fuel injection hole 10, so that the penetration force is reduced by the generated turbulent flow. Is done. 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.

  In particular, in this embodiment, the inner peripheral wall 13 of the fuel injection hole 10 has a large-diameter wall 13a having a radius larger than the radius of the long axis 11, a small-diameter wall 13b having a radius smaller than the radius of the long axis 11, and these large diameters. The connecting wall 13c connects the diameter wall 13a and the small diameter wall 13b. From the side of the large diameter wall 13a having a small curvature, the fuel can easily enter the fuel injection hole 10, and from the side of the small diameter wall 13b having a large curvature. This makes it difficult not only to enter, but fuel different in movement collides in the fuel injection hole 10 to generate a larger turbulent flow and further reduce the penetration force, as well as the virtual that constitutes the large-diameter wall 13a. Since the circle K1 and the virtual circle K2 constituting the small-diameter wall 13b have the same center O ′, the length of the short axis 12 becomes constant in the circumferential direction of the fuel injection hole 10 and the injection flow rate can be easily managed. It becomes.

Moreover, the fuel injection holes 1 0 total hand, two intersection points A between the inner peripheral wall 13 and the major axis 11 of it, since one A of B is radially outside the pitch circle P, the valve seat member 3 Depending on the distance from the center of the fuel nozzle 10 to the fuel injection hole 10, the inclination angle of the fuel injection hole 10 with respect to the valve seat member 3, etc., there is a portion where the fuel is easily separated from the wall surface of the fuel injection hole 10 However, since the fuel injection hole 10 extends over the outer side and the inner side in the radial direction of the pitch circle P, it is possible to keep the separation part at a part of the fuel injection hole 10 and reduce the variation in the separation amount. it can. Moreover, since the nozzle hole dimension toward the radially outer side of the pitch circle P can be secured, the movement of the fuel to the outside can be promoted.

  Further, when the fuel injection hole 10 is formed by laser processing, when the inclination angle of the fuel injection hole 10 with respect to the valve seat member 3 is directed outward, interference between the laser beam L and the cylindrical portion 3b of the valve seat member 3 is caused. In order to avoid this, it is necessary to install an interference preventing member on the inner surface of the cylindrical portion 3b of the valve seat member 3, but in all the fuel injection holes 10, the radially outer portion of the pitch circle P in the fuel injection holes 10 is the valve seat. By being present at a position away from the center of the member 3, the axis l of the fuel injection hole 10 can hardly intersect with the rear end of the valve seat member 3 as shown in FIG. Therefore, since the outward movement of the fuel can be effectively promoted, the inclination angle of the fuel injection hole 10 with respect to the valve seat member 3 is not directed outward. Fuel can be injected outside Te, can hardly occur interference between the cylindrical portion 3b of the laser beam L and the valve seat member 3, it can be omitted installation of interference prevention member.

  In addition, the front end wall 3a of the valve seat member 3 is formed with a recess 14 having a bottom surface 14a passing through the axis l of the fuel injection hole 10 from the front, and the bottom surface 14a of the recess 14 is downstream of the fuel injection hole 10. Since the end is open, the downstream end of the fuel injection hole 10 can be protected from contact with other members.

Moreover, all the fuel injection holes 1 0, with respect to the straight line extending in the radial direction from the center O of the pitch circle P at the intersection of the major axis 11 and minor axis 12, minor axis 12 is inclined on the same side And that the inlets of all the fuel injection holes 10 are arranged on a single pitch circle P, it becomes easy to equalize the injection flow rate and the spray length, and the management of the injection flow rate becomes easy.

  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. Further, it is not necessary to form the recess 14 in the front end wall 3a of the valve seat member 3.

3 ... Valve seat member 9 ... Valve seat 10 ... Fuel injection hole 11 ... Long shaft 12 ... Short shaft 13 ... Inner peripheral wall 15... Valve body A, B... Intersection between inner peripheral wall of fuel nozzle hole and long axis O... Pitch circle center P Pitch circle R1 ... Radius of major axis R2 ... Radius of pitch circle

Claims (2)

A valve seat member (3) having a valve seat (9) and a plurality of annularly arranged fuel injection holes (10) and injecting fuel from the fuel injection hole (10); and the valve seat (9), In-cylinder injection electromagnetic fuel injection valve comprising a valve body (15) for opening and closing the fuel injection hole (10) in cooperation with each other,
The fuel injection hole (10) is a long hole having a long axis (11) and a short axis (12), the long axis (11) is curved in an arc shape, and the long axis (11) The radius (R1) is smaller than the radius (R2) of the pitch circle (P) at the inlet of the fuel injection hole (10), and all the fuel injection holes (10) are centered on the pitch circle (P) ( The short axis (12) is inclined to the same side with respect to a straight line extending in the radial direction from O) toward the intersection of the long axis (11) and the short axis (12). 10 ), one of the two intersections (A, B) of the inner peripheral wall (13) and the long axis (11) is located outside the pitch circle (P) in the radial direction. An in-cylinder injection electromagnetic fuel injection valve. The in-cylinder injection electromagnetic fuel injection valve according to claim 1, wherein the inlets of all the fuel injection holes (10) are arranged on the single pitch circle (P).

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