JPS6354900B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a fuel injection valve that controls the injection amount of fuel supplied to an engine section of an internal combustion engine.

The method of sharing a single fuel injection valve for multiple cylinders of a multi-cylinder engine is compared to the method of installing a fuel injection valve for each of the multiple cylinders.
This has the advantage of improving combustibility at low decelerations and simplifying the system, but a major challenge is expanding the control range of the amount of fuel injected by a single valve. As a countermeasure to this problem, an example of a conventional single fuel injection valve sharing system is shown in Figure 1, which is a slightly modified version of the solenoid valve disclosed in Japanese Patent Application Laid-open No. 56-44450. . 1 is an electromagnetic coil excited by an energizing current passing through a lead wire 2; 3 is a bobbin portion that insulates and supports the coil 1; 4 is a fixed iron core of a magnetic circuit excited by the electromagnetic coil 1; 5 is the fixed iron core. 6 is the outer wall of the device which also serves as the outer yoke of the magnetic circuit; 7 is the end of the central magnetic path formed by the fixed iron core 4; 8 is the end of the outer magnetic path formed by the outer yoke 6; A base part is fixedly supported by the outer wall part 6, 10 is a fuel injection port attached to the lower end of the through hole of the base part 9, and 11 is an inverted ladder-shaped cross section formed surrounding the upper part of the through hole of the base part 9. conical valve seat,
12 is a spherical portion 1 that can come into contact with the conical valve seat 11;
3, a hemispherical valve body part 14, a plate-shaped valve body part 15 fixedly supported on the upper part of the hemispherical valve body part 12;
16 is the central hole periphery of the plate-shaped valve body portion 14 facing the central magnetic path end portion 7 with a gap g in between; 16 is the plate-shaped valve facing the outer circumferential magnetic path end portion 8 with a gap g in between; The periphery of the body portion 14, 17 is a spring stretched between the bottom surface of the fixed core central shaft portion 5 and the bottom surface of the cavity of the hemispherical valve body portion 13, and 18 is the plate-shaped spring that passes through the outer wall portion 6. The injection port 10 passes through the valve body portion 14 and the surrounding portion of the hemispherical valve body portion 12 and through the valve gap between the valve body spherical surface portion 13 and the valve seat conical surface 11.
This is the fuel route that leads to.

When the electromagnetic coil 1 is not energized, the spring 17
Due to the tension, the spherical portion 13 of the hemispherical valve body 12
is brought into pressure contact with the valve seat conical surface 11, and the fuel injection path 18 leading to the injection port 10 is blocked. On the other hand, when the electromagnetic coil 1 is energized, the magnetic circuit via the gap g between the central magnetic path formed by the fixed iron core 4, the outer circumferential magnetic path formed by the outer wall portion 6, and the plate-shaped valve body portion 14 is excited. , the spring 17 due to the magnetic attraction force through the air gap g.
The fuel passage leading to the injection port 10 is opened by lifting the plate-shaped valve body part 14 and the hemispherical valve body part 12 together from the state of contact with the valve seat conical surface 11 against the force. As in the case of conventional electromagnetic valves of this type, the amount of fuel flowing through the valve section can be controlled by repeating energization and interruption of the current to the electromagnetic coil 1 at a desired rate. .

The above-mentioned fuel injection valve is a single-valve type for multiple cylinders instead of a multiple-valve type in which an injector is provided for each cylinder in a multiple-cylinder type, and from the above-mentioned circumstances, it is necessary to ensure the desired maximum flow rate with a single valve. Therefore, it became necessary to increase the outer diameter of the valve body. However, increasing the size of the valve body structure in which the plate-like valve body part 14 and the hemispherical valve body part 12 are integrated as described above increases the weight of the movable part and increases the desired power amount of the electromagnetic coil 1. In addition to causing uneconomical results due to an increase in the cross-sectional area of the magnetic circuit, the increase in inertia tends to cause bouncing when the valve body operates, which reduces the accuracy of fuel flow control in low flow areas. accompanied by. In addition, corrosion is likely to occur at the welding and other processing locations required to integrally connect the plate-shaped portion 14 and the hemispherical portion 12 of the valve body, and there is a great possibility that reliability will be reduced.

The purpose of the present invention is to solve the above-mentioned difficulties with conventional fuel injection valves, and the above-mentioned object has been achieved by a configuration having the features described in the claims section above. .

FIG. 2 shows a longitudinal cross-sectional view of an embodiment of the present invention,
The numbers 1 to 10 in FIG. 2 indicate the same parts as the numbers 1 to 10 in FIG. 21 is a plate-shaped valve body formed with a partially conical surface 22 that is in contact with the spherical surface of the valve seat 20, and 23 is a central magnetic path end in the valve body 21. Part 7
24 is an outer circumferential portion of the plate-shaped valve body that is opposed to the outer circumferential magnetic path end portion 8 via a gap g, and 25 is a bottom surface of the fixed core center shaft portion 5 and the above-mentioned This is a spring stretched between the upper surface of the plate-shaped valve body 21 and the upper surface of the plate-shaped valve body 21. It is desirable that the position at which the valve seat 20 is fixed through the base portion 9 is adjustable along the fuel flow direction.

In the embodiment of the present invention, when the electromagnetic coil 1 is not energized, the lower conical surface 22 of the plate-shaped valve body 21 is brought into pressure contact with the spherical head surface of the valve seat 20 due to the tension of the spring 25. Since the upper end of the hole 19 is blocked, communication of the fuel passage 18 to the injection port 10 via the hole 19 is blocked. On the other hand, when the electromagnetic coil 1 is energized, the magnetic circuit via the gap g between the central magnetic path formed by the fixed iron core 4, the outer circumferential magnetic path formed by the outer wall portion 6, and the plate-shaped valve body 21 is excited. , the plate-shaped valve body 21 is lifted from the state in which it is in contact with the valve seat 20 against the force of the spring 25 due to the magnetic attraction force through the gap g, so that the fuel path 1
A flow path leading from the valve seat 8 to the injection port 10 via the valve seat passage hole 19 is opened.

As is clear from the description of the above embodiments, the present invention allows the movable valve body to be formed into a substantially plate-like shape as a whole without requiring the hemispherical valve body portion of the conventional case shown in FIG. , the shape was simplified and the weight was significantly reduced. This reduces the amount of power or electricity required for valve operation, and
The effect of preventing the bounce phenomenon caused by inertia is obtained, and in particular, even if the contact surface between the valve element and the valve seat is increased to increase the set flow rate, the weight of the valve element 21 increases very little, so the fuel injection amount can be increased from a small flow rate to a maximum. Highly accurate injection amount control can now be achieved over a wide range of flow rates. In addition, as it has become sufficient to form the valve body with a single plate as described above, there are no parts on the valve body that require welding, and corrosion of the welded parts due to actual use of the injection valve is eliminated. This eliminates the possibility of reliability problems. Note that it is desirable that the surface of the plate-shaped valve body 21 that comes into contact with the valve seat 20 be hardened.

In the above embodiment, a case has been described in which the valve body is actuated by the magnetic attraction force generated by the electromagnetic coil, but the effects of the present invention can also be obtained if the valve body is actuated by mechanical means instead of electromagnetically. It is clear that

As explained above, according to the present invention, the movable valve body is provided with a concave partial conical surface, and the valve seat facing the same is provided with a convex partial spherical surface, so that conical surface-to-spherical contact is established between the two. This made it possible to make the movable valve body lighter without compromising the sealing performance between the two.
Furthermore, by forming the valve seat into a convex partially spherical surface, it becomes difficult for foreign matter to remain at the contact surface with the conical surface, and it is possible to eliminate the dripping phenomenon caused by foreign matter being caught in the valve seat.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view showing an example of a conventional fuel injection valve, and FIG. 2 is a longitudinal side view showing an embodiment of the present invention. 1... Electromagnetic coil, 2... Lead wire, 3... Coil bobbin part, 4... Fixed iron core, 5... Fixed iron core center shaft part, 6... Outer yoke part, 7... Center magnetic path end part, 8... End part of the outer magnetic path, 9... Base part, 10
... Spout port, 11 ... Valve seat conical surface, 12 ... Hemispherical valve body part, 13 ... Spherical part, 14 ... Plate-shaped valve body part, 15 ... Plate-shaped valve body central part, 16 ...... Plate-shaped valve body outer periphery, 17... Spring, 18... Fuel path, 19
...Fuel hole, 20... Spherical valve seat, 21... Plate-shaped valve body, 22... Conical surface of plate-shaped valve body, 23... Center part of plate-shaped valve body, 24... Peripheral part of plate-shaped valve body , 25...spring, g...gap.

Claims (1)

[Scope of Claims] 1. A plate-shaped movable valve body in which a partially concave conical surface is formed in a fuel passage leading to a fuel injection port; A fixed spherical valve seat having a partially convex spherical surface that is in contact with the conical surface and surrounding the through hole that is blocked by the valve seat is interposed in a positional relationship that allows the conical surface and the spherical surface to come into contact with each other. A fuel injection valve characterized by: 2. The fuel injection valve according to claim 1, wherein the fixed position of the fixed spherical valve seat in the fuel passage is adjustable. 3. The fuel injection valve according to claim 1 or 2, wherein the valve movement of the plate-shaped movable valve body relative to the fixed spherical valve seat is controlled by magnetic attraction force. 4. Claims characterized in that the central part and the outer peripheral part of the plate-shaped movable valve body are opposed to each other through a gap between the central magnetic path and the peripheral magnetic path of a magnetic circuit excited by an electromagnetic coil. The fuel injection valve according to item 3.