JPH05280315A - Electromagneticaly driven valve - Google Patents

Abstract

PURPOSE:To control current to a moving coil for generating a magnetic field in a cavity by detecting directly a magnetic flux in the cavity in which the moving coil giving a thrust to an electromagnetic valve is disposed. CONSTITUTION:A moving coil 3 for driving an electromagnetic valve 1 is disposed in a cavity 24 between the center magnetic pole 21 of a field system 2 and a side magnetic pole 22, and a Hall element 25 for detecting magnetism is mounted on the tip of the side magnetic pole 22. In electrifying the field system 2, a detecting signal from the Hall element 25 orthogonal to the effective magnetic flux in the cavity 24 is inputted to a controller 5 to command a drive circuit 4 according to the signal and controllably electrify the moving coil 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically driven valve arranged at an intake / exhaust port provided in a cylinder of an engine and driven by an electromagnetic force.

[0002]

2. Description of the Related Art Conventionally, an intake / exhaust valve arranged in a cylinder is mechanically opened and closed by a camshaft driven based on the rotation of a crankshaft, a rocker arm, etc. Because of their small size, various electromagnetically driven valves that are driven by electromagnetic force and have a high degree of freedom have been tried.

As an electromagnetically driven valve of this type, for example, a valve control device having a valve driving means for driving an intake / exhaust valve which is always biased in a closing direction by a magnetic force of a permanent magnet in an opening direction by an electromagnetic force is disclosed in JP-A-2-123210. It is shown in the publication.

In order to improve the driving characteristics of the electromagnet of the electromagnetic mechanism used for such valve driving means, the current supplied to the electromagnet is checked, and the driving state of the valve is controlled by controlling this current. There is.

[0005]

As described above, the current waveform flowing through the winding of the electromagnet is improved by controlling the current supplied to the electromagnet, but the magnetic force for operating the valve has leakage magnetic flux. Strictly speaking, there is an inconvenience that a difference may occur between the current waveform passing through the winding and the magnetic force to be actuated, resulting in a difference.

The present invention has been made in view of the above problems, and its purpose is not to check the current supplied to the electromagnet but to detect the state of the magnetic flux that operates the valve.
An object of the present invention is to provide an electromagnetically driven valve that seeks to improve drive control of the valve.

[0007]

In order to achieve the above object, according to the present invention, there is provided a field portion having a cylindrical magnetic pole and a gap for generating a magnetic flux along the outer peripheral wall thereof, and the field portion arranged in the gap. In an electromagnetically driven valve driven by an electromagnetic force with a cylindrical movable coil, a magnetic detection unit arranged in a portion in contact with the gap for detecting a magnetic flux in a radial direction of a cylindrical magnetic pole, and a signal from the magnetic detection unit An electromagnetically driven valve having an energization control means for controlling energization to the field part is provided.

[0008]

[Function] Since the actual state of the effective magnetic flux is detected by the Hall element provided in the field part of the state of the magnetic flux in the air gap where the movable coil is directly connected to the electromagnetic valve, and the energizing current is controlled based on this detection signal, Since the current is directly controlled by the state of the magnetic flux, accurate drive control can be performed as compared with the control based on the current.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the construction of an embodiment of an electromagnetically driven valve according to the present invention, and FIG. 2 is an enlarged view of the essential parts of this embodiment.

In these drawings, reference numeral 1 denotes an electromagnetic valve, a stem 11 of which is vertically reciprocally supported by a valve guide 12, and when the valve is closed, a valve portion 14 is provided at a valve seat 13 at an intake port or an exhaust port of a cylinder. Sit down and close the flow path.

Reference numeral 2 denotes a field portion, a core portion 20 having a central magnetic pole 21 and a plurality of side magnetic poles 22, and the side magnetic pole 2.
It is provided with a plurality of coils 23 wound around and excited by two, and a strong magnetic flux is passed through a gap 24 between the central magnetic pole 21 and the side magnetic poles 22 by a current supplied to the coils 23. A Hall element 25, which functions as a magnetic flux sensor by detecting the orthogonal magnetic flux by the Hall effect, is attached to the tip of the side magnetic pole 22.

Reference numeral 3 denotes a movable coil, which is wound in a cylindrical shape and is arranged in the gap 24 to generate a thrust in the vertical direction by a magnetic force generated by energization and a magnetic flux in the gap 24. The electromagnetic valve 1 coupled to the above-mentioned part via the upper seat 15 and the like is opened and closed by the thrust of the movable coil 3. Reference numeral 16 is a spring that biases the electromagnetic valve 1 in the valve closing direction by its elastic force.

Reference numeral 4 denotes a drive circuit using a semiconductor element, which supplies electric power to the field magnet section 2 by a signal from the controller 5 to generate a magnetic flux in the air gap 24. The controller 5 is composed of a microcomputer. , Which has preset current command value data for the field unit 2, inputs signals from the engine speed and the Hall element 25, etc., performs processing in the comparison circuit 51, and instructs the drive circuit 4. To issue a current command to control the drive of the electromagnetic valve 1.

Next, the operation of the present embodiment thus constructed will be explained. When the electromagnetic valve 1 is driven, a command is issued from the controller 5 to the drive circuit 4, and the magnetic field 2 is energized to generate a magnetic flux in the air gap 24. Occurs. The generated magnetic flux is detected by the Hall element 25 at the tip of the side magnetic pole 22 as to whether it is an effective magnetic flux that reaches the central magnetic pole 21 at right angles to the element itself, and a detection signal based on the effective magnetic flux is used as a comparison circuit 5
Sent to 1. Then, the controller 5 performs a predetermined process, issues an appropriate current command to the drive circuit 5 to control the magnetic flux in the air gap 24 to an appropriate value, and in combination with the magnetic force due to the energization of the movable coil 3, the electromagnetic valve is controlled. The drive of 1 will be well implemented.

Although the present invention has been described with reference to the above embodiments, various modifications can be made within the scope of the gist of the present invention, and these modifications are not excluded from the scope of the present invention.

According to the present invention as in the above embodiments,
A Hall element that detects a quadrature magnetic flux is attached to the air gap where the moving coil is arranged, and the energization to the field section is controlled according to the detection signal from the element and the engine rotation signal. Compared with the case where energization control is performed in accordance with the current of 1, the state of the effective magnetic flux can be directly grasped, and there is an effect that drive control of the electromagnetic valve can be sufficiently performed. Further, there is also an advantage that an abnormality of the coil of the field part can be properly detected when the magnetic flux is not generated even when the power is supplied.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of an electromagnetically driven valve according to the present invention.

FIG. 2 is an explanatory view showing an enlarged main part thereof.

[Explanation of symbols]

 1 ... Electromagnetic valve 2 ... Field part 3 ... Moving coil 5 ... Controller 21 ... Central magnetic pole 24 ... Air gap 25 ... Hall element

Claims (2)

[Claims] 1. An electromagnetically driven valve driven by the electromagnetic force of a field magnet portion having a cylindrical magnetic pole and a gap for generating a magnetic flux along the outer peripheral wall thereof, and a cylindrical moving coil arranged in the gap. A magnetic detection unit arranged in a portion in contact with the air gap for detecting a magnetic flux in the radial direction of the cylindrical magnetic pole; and an energization control unit for controlling energization to the field unit according to a signal from the magnetic detection unit. Characteristic electromagnetically driven valve. 2. The electromagnetically driven valve according to claim 1, wherein the magnetic detection means is a Hall element arranged orthogonal to the magnetic flux in the radial direction.