JPH0589865U - Electromagnetic fuel injection valve - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve responsiveness by quickly eliminating residual magnetic flux due to eddy current generated when power supply to the solenoid coil that drives the needle valve is cut off. [Configuration] Solenoid coil 2 for driving an injection valve
A secondary coil 22b that emits a magnetic field in the opposite direction to the magnetic field generated by the solenoid coil 22a is provided in the main body together with 2a. When the valve is opened, the injection valve is opened by the magnetic field obtained by exciting the solenoid coil 22a, and when closed The power supply to the solenoid coil 22a is stopped and the secondary coil 22b is excited to generate a reverse magnetic field, which eliminates the residual magnetic flux at the end of the valve opening operation.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electromagnetic fuel injection valve used in an internal combustion engine, and in particular, an electromagnetic fuel injection valve with improved response by rapidly eliminating residual magnetic flux when power supply to a solenoid coil that drives a needle valve is cut off. The present invention relates to a fuel injection valve.

[0002]

[Prior Art]

 FIG. 6 is a vertical cross-sectional view of an example of a conventional electromagnetic fuel injection valve. Fuel flows into the electromagnetic fuel injection valve in the direction of arrow Z parallel to the central axis.

A foreign matter removing strainer 31 is inserted into the fuel inlet port. A fixed iron core 2 that is also made of a magnetic material and is integrally molded with a hollow sleeve 2c for fuel supply is housed inside a housing 1 that is made of a magnetic material and has a cylindrical shape. The fixed iron core 2 is composed of an inner iron core 2a and an outer iron core 2b, and an end 2d facing a movable iron core 8 described later is a flat surface. A solenoid coil 22 wound around a bobbin 21 is inserted into a space formed between the inner core 2a and the outer core 2b.

A coil spring 26 and a pipe-shaped spring stopper 27 are inserted into the sleeve 2c (inner iron core 2a). The spring stopper 27 is positioned relative to the housing 1 at a position such that the force of the coil spring 26 pressing the collar-shaped movable iron core 8 fixed to the needle valve (hereinafter, simply referred to as valve) 10 is appropriate. It is fixed.

At the tip of the housing 1, a valve seat 11 in which a valve 10 is slidably accommodated is fixed by screwing a cap nut 15 onto the tip of the housing 1. In the illustrated example, the valve 10 and the valve seat 11 are formed in an elongated shape so that the fuel can be directly injected into the combustion chamber of a cylinder (not shown).

The constant reciprocating movement of the valve 10 corresponding to the valve opening is defined by bringing the flat surface 8 a of the movable iron core 8 formed into a brim into contact with the flat surface 2 d of the fixed iron core 2. The valve 10 is provided with guide portions 30a and 30b that slide on the inner wall of the valve seat 11 in order to determine the position in the valve seat 11 in the direction perpendicular to the reciprocating motion. Each of the guide portions 30a and 30b is formed by flattening a cylindrical body on four sides, and a fuel passage is provided between the flattened surface and the valve seat 11.

The fuel filtered by the strainer 31 passes through the hollow portion of the sleeve 2 c and the central portion 29 of the spring stopper 27, and passes through the fuel passage 12 provided in the movable iron core 8 to the valve 10 and the valve seat 11. Is led to the space formed by.

In such a configuration, the movable iron core 8 is constantly pressed by the spring 26 (when the solenoid coil 22 is not energized), and fuel injection from the injection port 17 is blocked. On the other hand, when the solenoid coil 22 is energized, the movable iron core 8 is attracted by the flat surface 2d of the fixed iron core 2 against the repulsive force of the spring 26, and the tip of the valve 10 separates from the valve seat 11. The fuel supplied into the seat 11 is injected from the injection port 17.

[0009]

[Problems to be solved by the device]

 However, in the electromagnetic fuel injection valve having the above-mentioned structure, when the exciting current supplied to energize the solenoid coil 22 is cut off, as shown in FIG. 5, the inner side of the magnetic circuit is formed. Eddy currents 32 and 33 are generated in the plane perpendicular to the magnetic flux generated by the solenoid coil 22 in the iron core 2a and the outer iron core 2b. Note that FIG. 5 is a sectional view taken along line AA of FIG.

Since the eddy currents 32 and 33 act so as to prevent a decrease in magnetic flux, the electromagnetic attraction acts on the movable iron core 8 even after the current is cut off, and the valve 10 is returned due to the repulsive force of the coil spring 26. This hinders the responsiveness. Such a phenomenon is particularly remarkable in the fuel injection valve having a high hold current, as in the case where a high output is required.

An object of the present invention is to solve the above-mentioned problems of the prior art and to quickly eliminate the residual magnetic flux generated when the power supply to the solenoid coil 22 is cut off, thereby improving the responsiveness of the valve 10. It is in.

[0012]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention provides a drive control device for an electromagnetic fuel injection valve, which opens a fuel injection valve by an electromagnetic force generated by a solenoid coil and closes the fuel injection valve by a repulsive force of a spring. A first solenoid coil for generating a forward magnetic field for opening the valve and a second solenoid coil for generating a reverse magnetic field are provided, and the first and second solenoid coils are coaxially and adjacently arranged. It is characterized in that

[0013]

[Action]

 At the end of the valve opening operation, by stopping the power supply to the first solenoid coil and temporarily supplying the power to the second solenoid coil, the magnetic flux remaining in the magnetic circuit at the end of the valve opening operation can be eliminated. Since it can be quickly extinguished by the reverse magnetic field generated by the second solenoid coil, a quick valve closing operation is possible and the responsiveness of the fuel injection valve is improved.

[0014]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2 is a schematic diagram for explaining the basic concept of the present invention. According to the present invention, a solenoid coil 22a for driving the injection valve and a secondary coil 22b for emitting a magnetic field in a direction opposite to the magnetic field generated by the solenoid coil 22a are provided in the main body, and the solenoid coil 22a is excited when the valve is opened. The injection valve is opened by the magnetic field obtained in this way, and when the valve is closed, the power supply to the solenoid coil 22a is stopped and the secondary coil 22b is excited to generate a reverse magnetic field. The residual magnetic flux of was eliminated to enable quick valve closing operation.

FIG. 1 is a vertical sectional view of a main portion of an electromagnetic fuel injection valve according to an embodiment of the present invention, and FIG. 4 is a top view thereof, and the same symbols as those used above represent the same or equivalent portions. There is.

In the present invention, the two coils 22a and 22b are wound side by side along the axial direction on the bobbin 21, and magnetic fields in opposite directions are generated from the respective coils 22a and 22b. ..

In this case, four coil terminals 13 are required as shown in FIG. 4 (a), but by sharing one terminal for each of the two coils 22a and 22b, the coil terminal 13 shown in FIG. It is also possible to set it in three places like).

FIG. 3 is a diagram comparing the operation of the conventional electromagnetic fuel injection valve and the electromagnetic fuel injection valve to which the present invention is applied. FIG. 3 (a) shows the magnetic flux Φ (vertical axis) and time. (B) shows the relationship between the position of the needle valve 10 (vertical axis) and time (horizontal axis), (c) shows the state of power supply to the coil 22a, (d) in FIG. ) Indicates the power supply state to the coil 22b.

When the coil 22a is excited at time t0 and the magnetic force due to the magnetic flux Φ overcomes the repulsive force of the coil spring 26 at time t1, the needle valve 10 starts moving in the valve opening direction.

After that, at time t2, the power supply to the coil 22a is cut off, and when the repulsive force of the coil spring 26 overcomes the magnetic force of the residual magnetic flux Φ, the needle valve 10 starts to return in the valve closing direction.

At this time, according to the present invention, the secondary coil 22b is excited immediately after the power supply to the coil 22a is cut off, and a reverse magnetic field that cancels the residual magnetic flux is generated, so that the residual magnetic flux quickly falls ( (Solid line), at time t3, the needle valve 10 begins to return in the closing direction.

On the other hand, in the conventional technique, since the residual magnetic flux on the magnetic circuit is hard to disappear, the needle valve 10 starts to return only after the time t4 (> t3) (broken line).

As described above, according to the present embodiment, when the valve is closed, the magnetic field in the opposite direction to that when the valve is opened is temporarily generated by the solenoid coil 22b, so that the residual magnetic flux at the end of the valve opening operation is quickly eliminated. As a result, quick valve closing operation is possible and the responsiveness of the fuel injection valve is improved.

Moreover, in the present invention, since the solenoid coils 22a and 22b are arranged adjacent to each other on the same axis, the magnetic paths formed by the coils 22a and 22b are different from those in the case where the coils 22a and 22b are overlapped. It can be shortened and efficiency can be increased.

[0026]

[Effect of the device]

 As is clear from the above description, according to the present invention, the magnetic flux remaining in the magnetic circuit can be quickly extinguished at the end of the valve opening operation, so that the responsiveness of the electromagnetic fuel injection valve is improved. ..

Further, since the two solenoid coils are arranged coaxially and adjacently to each other, the magnetic path by each coil can be shortened and efficiency can be improved as compared with the case where they are arranged in an overlapping manner. it can.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an electromagnetic fuel injection valve according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the basic concept of the present invention.

FIG. 3 is a diagram for explaining the effect of the present invention.

4 is a top view of FIG. 1. FIG.

5 is a sectional view taken along line AA of FIG.

FIG. 6 is a vertical cross-sectional view of an example of a conventional electromagnetic fuel injection valve.

[Explanation of symbols]

1 ... Casing, 2 ... Fixed iron core, 2a ... Inner iron core, 2b
... outer iron core, 8 ... movable iron core, 10 ... needle valve, 1
1 ... Valve seat, 13 ... Coil terminal, 15 ... Cap nut, 21 ... Bobbin, 22a, 22b ... Solenoid coil, 31 ... Foreign matter removing strainer, 32, 33 ... Eddy current

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Hirose 4-1 Chuo 1-4-1, Wako-shi, Saitama Stock Research Institute Honda Technical Research Institute

Claims (2)

[Scope of utility model registration request] 1. A drive control device for an electromagnetic fuel injection valve, which opens a fuel injection valve with an electromagnetic force generated by a solenoid coil and closes it with a repulsive force of a spring. A first solenoid for generating a forward magnetic field for opening the fuel injection valve. An electromagnetic fuel injection valve, comprising: a coil; and a second solenoid coil for generating a reverse magnetic field, wherein the first and second solenoid coils are coaxially and adjacently arranged. 2. The electromagnetic fuel injection valve according to claim 1, wherein the first and second solenoid coils are wound around the same bobbin.