JPH10288014A - Electromagnetic driven valve for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exercise the excellent power saving characteristic at the time of initial drive of an armature, which is held at a neutral position, by generating the electromagnetic force in an electromagnet at a cycle, which accurately matches with the starting cycle of the armature, in a process for controlling the start. SOLUTION: When constraint of a movable part 50 of an electromagnetic driven valve 10 is released at a position displaced from a neutral position, the movable part 50 starts the simple harmonic motion at a natural oscillation cycle. Amplitude with the simple harmonic oscillation of the movable part 50 generates the electromagnetic force at the time of displacing to a first and a second electromagnets 32, 38. In the case where a start of the electromagnetic driven valve 10 is required, exciting current is alternately supplied to an upper coil 34 and a lower coil 40 at the predetermined oscillation cycle as one cycle so as to attract an armature 30, which is held at a neutral position, toward the upper core 36. In this process for controlling the start, the electromagnetic driven valve 10 changes the cycle for supplying the exciting current to the upper coil 34 and the lower coil 40 in response to the amplitude of the movable part 50.

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 of an internal combustion engine, and more particularly to an electromagnetically driven valve of an internal combustion engine that functions as an intake valve or an exhaust valve of the internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Laid-Open Publication No.
As disclosed in Japanese Patent No. 913, an electromagnetically driven valve of an internal combustion engine is known. The conventional electromagnetically driven valve includes a valve body functioning as an intake valve or an exhaust valve of the internal combustion engine, and an armature connected to the valve body. The valve body and the armature can be displaced in the axial direction of the valve body. Hereinafter, the valve body and the armature will be referred to as movable parts.

A first electromagnet and an upper spring are arranged above the armature. A second electromagnet and a lower spring are provided below the armature. The armature is held at a neutral position by an upper spring and a lower spring. Each of the first electromagnet and the second electromagnet generates an electromagnetic force for attracting the armature when an exciting current is supplied.

According to the above-mentioned conventional electromagnetically driven valve, by supplying an exciting current to the first electromagnet, the movable portion held by the upper spring and the lower spring can be displaced toward the first electromagnet. When the supply of the exciting current to the first electromagnet is stopped after the armature is displaced to the first electromagnet side, the movable portion starts simple oscillation by the spring force of the upper spring and the lower spring.

[0005] The period T of the simple vibration coincides with the natural vibration period T ₀ = 2π√ (M / K) determined by the mass M of the movable part and the spring constants K of the upper spring and the lower spring. Therefore, in the above-described conventional device, after the supply of the exciting current to the first electromagnet is stopped, the predetermined time “T ₀ /
At the time when 2 "has elapsed, it can be determined that the movable portion has reached the vicinity of the second electromagnet.

[0006] When an exciting current is supplied to the second electromagnet when the movable section reaches the vicinity of the second electromagnet, it is possible to generate an electromagnetic force for attracting the armature to the second electromagnet. When the above-described electromagnetic force is generated, the armature can be displaced until the armature reaches the second electromagnet, compensating for the sliding loss generated during the simple vibration. Thereafter, the valve body can be opened and closed by repeatedly supplying an exciting current to the first electromagnet and the second electromagnet at an appropriate timing. As described above, according to the above-described conventional electromagnetically driven valve, after the armature held at the neutral position is once drawn to the first electromagnet side, the valve body is operated with low power consumption by utilizing the simple vibration of the movable portion. Can be opened and closed.

In the above-described conventional electromagnetically driven valve, the armature held at the neutral position can be drawn to the first electromagnet side by continuously supplying a large exciting current to the first electromagnet. However, according to such a method, large power is consumed when the armature is drawn toward the first electromagnet. For this reason, the above-mentioned conventional electromagnetically driven valve is
When the armature held at the neutral position is attracted to the first electromagnet, start control for supplying an exciting current to the first electromagnet and the second electromagnet alternately with the above-described natural oscillation period T ₀ as one cycle is executed. I do.

According to the starting control described above, the amplitude of the movable portion is gradually increased without supplying an extremely large exciting current to the first electromagnet and the second electromagnet. Can be displaced to the side. Therefore, according to the above-described conventional electromagnetically driven valve, the movable portion held at the neutral position can be drawn to the first electromagnet side with low power consumption.

[0009]

However, the above-described natural vibration period T ₀ is a period realized when the movable portion oscillates simply with only the spring force of the upper spring and the lower spring as an external force. On the other hand, in the above-described conventional electromagnetically driven valve, an electromagnetic force is used for driving the movable portion during both the start control and the steady operation.

[0010] The electromagnetic force during the steady operation is merely used as a supplement to compensate for the sliding loss caused by the sliding of the movable part. In this case, the vibration period T of the movable part
Substantially coincides with the natural oscillation period T ₀ . Therefore, during the steady operation, it is substantially regarded as the natural vibration period T ₀ the vibration period T of the movable portion does not occur any inconvenience. On the other hand, in the process of the start control described above, the electromagnetic force is used to forcibly increase the amplitude generated in the movable portion by the simple vibration. In this case, the vibration period T of the movable part is equal to the natural vibration period T
_It shows a tendency to lengthen compared to ₀ .

[0011] The tendency of prolongation appearing in the vibration period T of the movable part becomes smaller as the electromagnetic force acting between the first electromagnet or the second electromagnet and the armature is stronger. The electromagnetic force acting between the first electromagnet or the second electromagnet and the armature increases as the distance between them decreases. For this reason, the tendency of the vibration cycle T to be prolonged during the start control process is such that the longer the distance between the first electromagnet and the armature and the longer the distance between the second electromagnet and the armature, that is, the smaller the amplitude of the movable part. It becomes more noticeable.

As described above, in the electromagnetically driven valve, the phenomenon in which the movable portion vibrates at a period T longer than the natural oscillation period T ₀ during the execution of the start-up control, particularly at a stage where the amplitude of the movable portion is small, occurs. Occurs. In order to efficiently displace the armature held at the neutral position toward the first electromagnet, the oscillation period T of the movable portion coincides with the period at which the first electromagnet and the second electromagnet generate electromagnetic force. Is desirable. In this regard, the above-described conventional device is not always optimal for saving power of the electromagnetically driven valve.

The present invention has been made in view of the above points, and provides an electromagnetically driven valve of an internal combustion engine that exhibits excellent power saving characteristics when an armature held at a neutral position is initially driven. The purpose is to do.

[0014]

The above object is achieved by the present invention.
As described in the above, a valve body constituting an intake valve or an exhaust valve of the internal combustion engine, an armature that operates together with the valve body, a spring member for urging the valve body and the armature toward a neutral position, and the armature And an electromagnet that generates an electromagnetic force that generates an electromagnetic force that draws an electromagnetic force at a predetermined period when the armature held at the neutral position is drawn toward the electromagnet. Starting control means for executing starting control to be performed, and cycle changing means for bringing the predetermined cycle closer to the natural oscillation cycle from a cycle larger than the natural oscillation cycle of the armature in the process of the starting control. This is achieved by an electromagnetically driven valve of an internal combustion engine.

In the present invention, the armature held at the neutral position is displaced toward the electromagnet by performing the start control. During the start control process, the electromagnet generates an electromagnetic force at a predetermined cycle. The predetermined period is set to a period larger than the natural vibration period while the amplitude of the armature is small, that is, while the armature vibrates at a longer vibration period than the natural vibration period. Thereafter, the predetermined cycle is made closer to the natural oscillation cycle as the amplitude of the armature increases and the oscillation cycle of the armature approaches the natural oscillation cycle. As described above, in the present invention, the starting control is executed so that the cycle in which the electromagnet generates the electromagnetic force and the oscillation cycle of the armature are accurately matched.

[0016] The above object is as described in claim 2.
A valve body that constitutes an intake valve or an exhaust valve of an internal combustion engine, an armature that operates together with the valve body, a spring member that urges the valve body and the armature toward a neutral position, and an electromagnetic force that draws the armature. The generated electromagnet,
In an electromagnetically driven valve of an internal combustion engine comprising: a start control means for executing start control for generating an electromagnetic force at a predetermined cycle on the electromagnet when the armature held at the neutral position is drawn toward the electromagnet; An exciting current changing means for changing an exciting current supplied to the electromagnet from a first current to a second current smaller than the first current in the process of the starting control. Is achieved by the electromagnetically driven valve.

In the present invention, the armature held at the neutral position is displaced toward the electromagnet by executing the start control. In the process of starting control, the first current is supplied to the electromagnet while the amplitude of the armature is small.
In this case, although the distance between the armature and the electromagnet is long, a large electromagnetic force acts between them. In this case, the tendency of the armature to be prolonged in the oscillation period is suppressed. On the other hand, after the armature amplitude increases, the second current (<first current) is supplied to the electromagnet. After the amplitude of the armature has increased, even if the exciting current supplied to the electromagnet is reduced to the second current, the oscillation period of the armature does not tend to be significantly prolonged. Therefore, the oscillation cycle of the armature during the start control is
It is maintained at a substantially constant cycle. During the execution of the start control, the electromagnet generates an electromagnetic force at a predetermined cycle corresponding to the predetermined cycle. Therefore, according to the present invention, the armature can be efficiently displaced to the vicinity of the electromagnet with low power consumption.

According to a third aspect of the present invention, there is provided an electromagnetically driven valve for an internal combustion engine according to the first aspect, wherein the exciting current supplied to the electromagnet in the process of the starting control is reduced by a second value. The present invention is also achieved by an electromagnetically driven valve of an internal combustion engine provided with an exciting current changing means for changing from one current to a second current smaller than the first current.

In the present invention, during execution of the start control,
The control that suppresses the fluctuation of the oscillation period of the armature by changing the excitation current supplied to the electromagnet, and the period at which the electromagnet generates the electromagnetic force and the amplitude of the armature by changing the period of supplying the excitation current to the electromagnet Both the control to match the cycle is executed. In this case, the armature can be efficiently displaced to the vicinity of the electromagnet by the start control while suppressing the power consumption to a necessary minimum.

[0020]

FIG. 1 shows an overall configuration diagram of an electromagnetically driven valve 10 according to an embodiment of the present invention. Electromagnetic drive valve 10
Is provided with a valve body 12. The valve body 12 is a member that constitutes an intake valve of the internal combustion engine. The valve body 12 is disposed on the cylinder head 13 so as to be exposed in the combustion chamber of the internal combustion engine. An intake port 14 is shown in the cylinder head 13 of the internal combustion engine. A valve seat 11 for the valve body 12 is formed in the intake port 14. Intake port 1
Reference numeral 4 denotes a conductive state when the valve body 12 is separated from the valve seat 11, and a cutoff state when the valve body 12 is seated on the valve seat 11.

A valve shaft 15 is fixed to the valve body 12. The valve shaft 15 is held slidably in the axial direction by a valve guide 16. The valve guide 16 is supported by the cylinder head 13. Also, the valve guide 16
, A lower cap 18 of the electromagnetically driven valve 10 is fixed. A plunger 20 made of a non-magnetic material is fixed to an upper portion of the valve shaft 15.

The lower retainer 21 is provided at the upper end of the valve shaft 15.
Has been fixed. Lower retainer 21 and lower cap 1
A lower spring 22 for generating a biasing force in a direction of separating the two is disposed between the lower spring 8 and the lower spring 8. The lower spring 22 holds the lower retainer 21, that is, the plunger 2.
0 and the valve element 12 are urged upward in FIG.

On the other hand, an upper retainer 24 is fixed to the upper end of the plunger 20. The lower end of the upper spring 26 is in contact with the upper part of the upper retainer 24. The upper spring 26 connects the upper retainer 24 with the plunger 20 and the valve body 12.
Is urged downward in FIG. A cylindrical upper cap 27 is provided around the upper spring 26 so as to surround the outer periphery thereof. Further, an adjusting bolt 28 is provided at an upper end of the upper cap 27. The upper end of the upper spring 26 is in contact with the adjuster bolt 28.

An armature 30 is joined to the plunger 20. The armature 30 is an annular member made of a magnetic material. Above the armature 30, the first
An electromagnet 32 is provided. The first electromagnet 32 includes an upper coil 34 and an upper core 36. A second electromagnet 38 is provided below the armature 30. The second electromagnet 38 includes a lower coil 40 and a lower core 42. The upper core 36 and the lower core 42 are members made of a magnetic material, and slidably hold the plunger 20 at the center thereof.

An outer cylinder 44 is provided on the outer periphery of the first electromagnet 32 and the second electromagnet 38. The outer cylinder 44 is
The electromagnet 32 and the second electromagnet 38 are both held so that a predetermined interval is ensured. The above-described upper cap 27 is fixed to the cylinder head 13 by a mounting bracket 46 and a mounting bolt 48 so as to contact the upper end surface of the first electromagnet 32. On the other hand, the lower cap 18 described above is
8 so as to contact the vicinity of the lower end of the cylinder head 13.
It is fixed inside. The adjuster bolt 28 described above is adjusted so that the neutral position of the armature 30 is at an intermediate point between the first electromagnet 32 and the second electromagnet 38.

Hereinafter, the operation of the electromagnetically driven valve 10 will be described. When the exciting current is not supplied to the upper coil 34 and the lower coil 40, the armature 30 is maintained at its neutral position, that is, between the first electromagnet 32 and the second electromagnet 38. When the supply of the exciting current to the upper coil 34 is started in a state where the armature 30 is maintained at the neutral position, an electromagnetic force that draws the armature 30 toward the first electromagnet 32 between the armature 30 and the first electromagnet 32. Occurs.

Therefore, according to the electromagnetically driven valve 10, by supplying an appropriate exciting current to the upper coil 34, the armature 30, the plunger 20, the valve body 12 and the like can be displaced toward the first electromagnet 32. it can. Hereinafter, a portion displaced together with the armature 30 is referred to as a movable portion 50. In the electromagnetically driven valve 10, the displacement of the movable part 50 can be continued until the armature 30 contacts the upper core 36. The electromagnetically driven valve 10 is designed such that the valve element 12 is seated on the valve seat 11 when the armature 30 is displaced until it contacts the upper core 36. Therefore, according to the electromagnetically driven valve 10, by supplying an appropriate excitation current to the upper coil 34, the valve body 12 can be displaced to the valve closing position.

When the valve element 12 is maintained at the closed position, the upper spring 26 and the lower spring 22
Generates an urging force for urging the movable portion 50 toward the neutral position. In such a situation, when the supply of the exciting current to the upper coil 34 is stopped, the movable portion 50 thereafter starts a simple oscillation by the spring force of the upper spring 26 and the lower spring 22.

The cycle T of the simple vibration is determined by the mass M of the movable section 50.
And the natural oscillation period T ₀ = 2π√ (M / M) determined by the spring constant K of the upper spring 26 and the lower spring 22.
K). Therefore, in the electromagnetically driven valve 10,
After the supply of the exciting current to the upper coil 34 is stopped,
When the predetermined time "T _0/2" has elapsed, the armature 3
It can be determined that 0 reaches the vicinity of the lower core 42.

When an exciting current is supplied to the lower coil 40 when the armature 30 reaches the vicinity of the lower core 42, an electromagnetic force that draws the armature 30 toward the second electromagnet 38 can be generated. When the above-described electromagnetic force is generated, the displacement of the movable portion 50 can be continued until the armature 30 contacts the lower core 42 by compensating for the sliding loss generated during the simple vibration.

The electromagnetically driven valve 10 is designed such that when the armature 30 contacts the lower core 42, the valve body 12 reaches the fully open position. Therefore, if the excitation current is supplied to the lower coil 40 at the predetermined timing as described above after the supply of the excitation current to the upper coil 34 is stopped, the valve body 12 is displaced from the valve-closed position to the fully-opened position with low power consumption. be able to.

When the supply of the exciting current to the lower core 42 is stopped after the armature 30 contacts the lower core 42,
Thereafter, the movable portion 50 starts a simple oscillation in a simple oscillation period of the natural oscillation period T ₀ . As a result, the armature 30 is displaced upward in FIG. Thereafter, at an appropriate timing, the upper coil 34 and the lower coil 40 are repeated.
When the excitation current is supplied to the valve body 12, the valve body 12 can be appropriately opened and closed with small power consumption.

As described above, in order to operate the electromagnetically driven valve 10 which is stopped, the armature 30 held at the neutral position is temporarily moved to the upper core 36 (or the lower core 4).
It must be displaced until it touches 2). The above displacement can also be generated by, for example, continuously supplying a sufficiently large exciting current to the upper coil 34. However, if the above-described displacement is to be generated by such a method, a large current is consumed when the electromagnetically driven valve 10 is started.

When the restraint of the movable portion 50 of the electromagnetically driven valve 10 is released at a position displaced from the neutral position, the movable portion 50 starts a simple vibration with the above-described natural vibration period T ₀ . Also,
The amplitude accompanying the simple vibration of the movable part 50 is such that when the movable part 50 is displaced toward the first electromagnet 32, an electromagnetic force is generated in the first electromagnet, and the movable part 50 moves toward the second electromagnet 38. The second electromagnet 38 can be grown by generating an electromagnetic force in the process of being displaced.

Therefore, when the electromagnetic force is generated in the first electromagnet 32 and the second electromagnet 38 so that the above conditions are satisfied when the electromagnetically driven valve 10 is started, a large force is applied to the upper coil 34 and the lower coil 40. A large amplitude can be given to the movable section 50 without supplying an exciting current. And the armature 30 is the upper core 3
6 (or the lower core 42) until the movable portion 50
, The electromagnetically driven valve 10 can be started with less power consumption.

The solenoid-operated valve 10 of this embodiment has an upper coil 34 and a lower coil 40
At this time, the armature 30 held at the neutral position is supplied to the upper core 36 (or the lower core 42) by alternately supplying the exciting current with a predetermined oscillation period T as one cycle.
To the side. Hereinafter, this control is referred to as start control. The electromagnetically driven valve 10 is characterized in that a cycle T for supplying an exciting current to the upper coil 34 and the lower coil 40 in the process of starting control is changed according to the amplitude of the movable part 50. Hereinafter, a characteristic portion of the electromagnetically driven valve 10 will be described with reference to FIGS.

FIG. 2A shows a displacement generated in the valve body 12 when the above-described start control is executed in the electromagnetically driven valve 10. FIG. 2B and FIG. 2C show that the excitation current supplied to the upper coil 34 or the lower coil 40 when the supply period T of the excitation current is made to coincide with the natural oscillation period T ₀ of the movable portion 50, respectively. The waveform is shown. FIG.
(C) and FIG. 2 (D) show the waveforms of the exciting current supplied to the upper coil 34 and the lower coil 40 when the starting control is executed in the present embodiment.

In executing the above-described start control, the excitation current supply period T
May be matched with the natural vibration period T ₀ of the movable part 50. However, the natural vibration period T ₀ of the movable part 50 is
This is a vibration cycle realized when the movable portion 50 makes a simple vibration using only the spring force of the upper spring 26 and the lower spring 22 as an external force. On the other hand, during execution of the start control, the movable portion 50 operates by receiving the electromagnetic force of the first electromagnet 32 and the second electromagnet 38 in addition to the spring force of the upper spring 26 and the lower spring 22. For this reason, during the execution of the start control, the movable unit 50
_Vibrates at a cycle different from ₀ .

In the process of amplifying the amplitude of the movable portion 50 along with the execution of the start control, the electromagnetic force generated by the first electromagnet 32 and the second electromagnet 38 is generated by the spring force of the upper spring 26 and the lower spring 22. When trying to lower the displacement speed of 50, it acts to prevent the lowering of the displacement speed against the spring force. When the electromagnetic force generated by the first electromagnet 32 and the second electromagnet 38 acts in this manner, the timing at which the movable unit 50 reaches the top dead center or the bottom dead center as compared with the case where the movable unit 50 oscillates simply. Is delayed. Therefore, if the start control is being executed, the oscillation period T of the movable portion 50, specifically, prolonged than the natural vibration period T ₀ as shown in FIG. 2 (A).

The tendency of the vibration period T of the movable part 50 to be prolonged appears as the electromagnetic force acting between the first electromagnet 32 or the second electromagnet 38 and the armature 30 becomes stronger. Becomes smaller as the value becomes smaller. The electromagnetic force acting between the first electromagnet 32 or the second electromagnet 38 and the armature 30 increases as the distance between them decreases. Therefore, the tendency of the vibration cycle T to be prolonged in the process of the start control is prominent in a region where the amplitude of the movable portion 50 is small, and disappears as the amplitude of the movable portion 50 increases.

FIG. 3 shows the number k of vibrations generated in the movable section 50 after the start control is started, and the vibration cycle T of the movable section 50.
FIG. After the start control is started, the amplitude of the movable section 50 increases as the number of vibrations k of the movable section 50 increases. For this reason, the vibration period T of the movable portion 50
Shows a tendency of approaching the natural vibration period T ₀ from a value larger than the natural vibration period T ₀ as the number of vibrations k increases after the start control is started.

As shown in FIGS. 2D and 2E,
In the electromagnetically driven valve 10 of the present embodiment, in consideration of the fact that the vibration period T of the movable portion 50 changes as described above in the process of starting control, a period _obtained by adding the correction value δ _k to the natural vibration period T ₀ “ The excitation current is supplied to the upper coil 34 and the lower coil 40 with T ₀ + δ _k ″ as one cycle.

FIG. 4 shows an example of a map referred to when a correction term δ _k used for correcting the supply cycle of the exciting current is _obtained . As shown in FIG. 4, after the start control is started, the correction term δ _k changes to a smaller value as the number k of vibrations generated in the movable unit 50 increases. According to the map shown in FIG. 4, the excitation current supply cycle T ₀ + δ _k is set to be the same as the vibration cycle T of the movable section 50 as the number of vibrations k of the movable section 50 increases after the start control is started. Can be made closer to the natural oscillation period T ₀ .

As described above, the tendency of the prolongation of the vibration period T of the movable portion 50 during the execution of the start control is suppressed as the electromagnetic force generated by the first electromagnet 32 and the second electromagnet 38 increases. . Therefore, in order to suppress the width of change that occurs in the vibration period T of the movable unit 50 during the execution of the start control, the upper coil 3 must be used when the amplitude of the movable unit 50 is small.
After supplying a large exciting current to the lower coil 4 and the lower coil 40 and increasing the amplitude of the movable section 50, the upper coil 34
It is appropriate to supply a small exciting current to the lower coil 40. Further, changing the exciting current as described above is also effective in reducing the power consumption accompanying the execution of the start control.

As shown in FIG. 2 (D), in the electromagnetically driven valve 10, the exciting current supplied to the upper coil 34 and the lower coil 40 has a small number of vibrations k and a first current when the amplitude of the movable section 50 is small. It is set to I _L. Further, at the stage where the amplitude of the movable portion 50 reaches a sufficiently large value, the exciting current is set to the current I ₂ smaller second than the first current I _L. Therefore, the electromagnetically driven valve 10
According to the above, during the execution of the start control, the vibration period T
Can be prevented from changing significantly, and the starting control can be completed with less power consumption.

FIG. 5 shows a flowchart of an example of a control routine executed in the electromagnetically driven valve 10 in order to realize the above functions. The routine shown in FIG. 5 is a routine that is repeatedly started after the ignition switch of the vehicle is turned on. When this routine is started,
First, the process of step 100 is executed. Step 10
At 0, it is determined whether or not the flag XCLOSE is in the ON state. The flag XCLOSE is a flag indicating whether or not the valve body 12 has been displaced to the valve closing position by performing the start control after the ignition switch is turned on. In this step 100, XCLOSE
If it is determined that = ON is established, the current routine is terminated without any further processing. On the other hand, if it is determined that XCLOSE = ON is not established, the process of step 102 is executed next.

In step 102, the counter k is incremented. The counter k is a counter for counting the number of repetitions of supplying the exciting current to the upper coil 34 and the lower coil 40. The counter k is set to "0" by the initialization process every time the ignition switch is turned on. In the present embodiment, the count value of the counter k matches the number of vibrations generated in the movable unit 50 after the start control is started. When the process of step 102 is completed, the process of step 104 is executed next.

In step 104, a process for setting the supply period T of the exciting current based on the count value of the counter k is executed. In the present step 104, specifically, a correction term δ _k corresponding to the count value of the counter k is obtained with reference to the map shown in FIG. 4 and the correction term δ _k is added to the natural vibration period t ₀ . Processing for storing the value as the supply cycle T is executed. When the process of step 104 is completed, the process of step 106 is performed next.

In step 106, a process for supplying the exciting current I to the upper coil 34 is executed. Exciting current I, the initial process is set to a first current I _L. When the process of step 106 is completed, the process of step 108 is performed next. Step 108
Then, it is determined whether or not half the time "T / 2" of the supply cycle T has elapsed after the excitation current is started to be supplied to the upper coil 34. The process of step 108 is repeatedly executed until it is determined that T / 2 has elapsed. As a result, if it is determined that the predetermined time T / 2 has elapsed, the process of step 110 is performed next.

In step 110, a process for stopping the supply of the exciting current to the upper coil 34 is executed. When the process of step 110 is performed, the process proceeds to step 112.
Is performed. In step 112, a process of supplying the exciting current I to the lower coil 40 is executed.
When the process of step 112 is completed, the process proceeds to step 1
Fourteenth processing is executed.

In step 114, it is determined whether or not a time "T / 2", which is a half of the supply cycle T, has elapsed after the supply of the exciting current to the lower coil 40 has started. The process of step 114 is repeatedly executed until it is determined that T / 2 has elapsed. As a result, when it is determined that the predetermined time T / 2 has elapsed, the process of step 116 is executed next.

In step 116, a process for stopping the supply of the exciting current to the lower coil 40 is executed. After the processing of step 116 is performed, the processing of step 118 is performed next. In step 118, it is determined whether or not the count value k ₀ of the counter k is equal to or greater than a predetermined value k ₀ . If k ≧ k ₀ does not hold as a result of the above determination,
After the start-up control is started, the number of vibrations of the movable portion 50 is determined to not reached yet the exciting current I from the first current I _L to the number to be changed to the second current I _S. in this case,
Next, the process of step 120 is performed. On the other hand, already k
If it is determined that ≧ k ₀ holds, it is determined that the time has come to make the exciting current I the second current I _S. In this case, the process of step 122 is performed next.

In Step 120, the process of the excitation current I to the first current I _L is performed. When the process of step 120 is completed, the process of step 124 is executed. In step 122, the exciting current I is changed to the second current I
_The process of _S is performed. When the process of step 122 ends, the process of step 124 is executed next.

In step 124, it is determined whether or not the count value of the counter k is equal to or greater than a predetermined number N. The predetermined number N is the number of times the movable section 50 should be vibrated by the start control. As a result of the above determination, if k ≧ N is not satisfied, it can be determined that the number of vibrations of the movable unit 50 is still insufficient. In this case, the above step 1 is repeated again.
02 and subsequent processes are executed. On the other hand, when K ≧ N holds, it can be determined that the amplitude of the movable section 50 has already sufficiently grown. In this case, the next step 126
Is performed.

In step 126, the flag XCLOSE
Is turned on. When the process of step 126 ends, the current routine ends. According to the above processing, after the start control is started, the predetermined number k
Until the _zero vibration occurs, the exciting current I is set to the first current _IL, and when the number of vibrations of the movable portion 50 becomes equal to or greater than the predetermined number k ₀ , the exciting current I is changed to the second current I _S (<I _L ). can do. For this reason, according to the electromagnetically driven valve 10 of the present embodiment, it is possible to reduce the width of the fluctuation that occurs in the vibration cycle of the movable section 50 during the execution of the start control.

According to the above-described processing, the supply cycle T of the exciting current I can always be accurately matched with the oscillation cycle of the movable section 50 during the execution of the start control. Therefore, according to the electromagnetically driven valve 10 of the present embodiment, the electromagnetically driven valve 10 can be shifted to the steady operation state very efficiently with low power consumption after the start thereof is requested. Incidentally, in the above-mentioned embodiment, the feed period T of the exciting current, a control for reducing toward the natural vibration period T ₀ from a large period than the natural period T _0, the exciting current I first current a control from the I _L is reduced to a second current I _S, although the performing together, the present invention is not limited thereto, these control may be executed independently of each other .

In the above embodiment, the exciting current is changed in two stages during the execution of the start control. However, the present invention is not limited to this. from the current I _L to the second current I _S, it may be changed stepwise or continuously. In the above embodiment, the upper spring 26 and the lower spring 22 correspond to the "spring member" of the first and second aspects, and the first electromagnet 32 and the second electromagnet 38 correspond to the first and the second aspects. The electromagnetically driven valve 10 corresponds to the “electromagnet” according to claim 2.
However, the “start control means” according to claim 1 and claim 2 by executing the processing of steps 106 to 116 executes the processing of steps 102 and 104 to execute the processing of steps 102 and 104. "Cycle change means"
Have been realized respectively. Further, in the above embodiment, the electromagnetically driven valve 10 is connected to the above-described steps 118 to 12.
By executing the second process, the “exciting current changing unit” according to the second and third aspects is realized.

[0058]

As described above, according to the first aspect of the present invention, it is possible to generate an electromagnetic force in the electromagnet at a period that accurately matches the armature starting period during the starting control process. Therefore, the electromagnetically driven valve of the internal combustion engine according to the present invention achieves excellent power saving characteristics.

According to the second aspect of the present invention, the oscillation period of the armature generated during the start control is maintained substantially constant while the exciting current supplied to the electromagnet during the start control is suppressed to a necessary minimum. Can be. Therefore, according to the electromagnetically driven valve of the internal combustion engine according to the present invention, excellent power saving characteristics can be realized. According to the third aspect of the present invention, both the control for keeping the oscillation period of the armature constant in the process of the start control and the control for making the period in which the electromagnet generates the electromagnetic force coincide with the amplitude period of the armature. Can be performed. Therefore, according to the electromagnetically driven valve of the internal combustion engine according to the present invention, excellent power saving characteristics can be realized.

[Brief description of the drawings]

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

FIG. 2A is a diagram illustrating displacement generated in a valve body when start control is performed in the electromagnetically driven valve of the present embodiment. FIG. 2B is a diagram showing a waveform of the excitation current supplied to the upper coil when the supply period of the excitation current matches the natural oscillation period T ₀ of the movable part. FIG. 2 (C)
FIG. 5 is a diagram illustrating a waveform of an exciting current supplied to the lower coil when a supply cycle of the exciting current is made to coincide with a natural oscillation cycle T ₀ of the movable portion. FIG. 2D is a diagram illustrating a waveform of the exciting current supplied to the upper coil when the start control is performed in the electromagnetically driven valve of the present embodiment. FIG. 2 (E)
FIG. 5 is a diagram illustrating a waveform of an exciting current supplied to a lower coil when starting control is performed in the electromagnetically driven valve of the present embodiment.

FIG. 3 is a diagram illustrating a relationship between the number of vibrations k generated in a movable portion after starting control is started in the electromagnetically driven valve of the present embodiment and a vibration period T of the movable portion.

4 is an example of a map which starting control in electromagnetically driven valve of this embodiment is referenced to determine the correction term [delta] _k when executed.

FIG. 5 is a flowchart of an example of a control routine executed in the electromagnetically driven valve of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electromagnetic drive valve 12 Valve body 20 Plunger 30 Armature 32 First electromagnet 34 Upper coil 36 Upper core 38 Second electromagnet 40 Lower coil 42 Lower core

Claims (3)

[Claims] 1. A valve constituting an intake valve or an exhaust valve of an internal combustion engine, an armature that operates together with the valve, a spring member for urging the valve and the armature toward a neutral position, and the armature. And an electromagnet that generates an electromagnetic force that attracts the electromagnetic force.When the armature held at the neutral position is attracted to the electromagnet side, an electromagnetic force is generated in the electromagnet at a predetermined cycle. Starting control means for executing starting control to be performed, and cycle changing means for bringing the predetermined cycle closer to the natural oscillation cycle from a cycle larger than the natural oscillation cycle of the armature in the process of the starting control. An electromagnetically driven valve for an internal combustion engine. 2. A valve body constituting an intake valve or an exhaust valve of an internal combustion engine, an armature that operates together with the valve body, a spring member for urging the valve body and the armature toward a neutral position, and the armature. And an electromagnet that generates an electromagnetic force that attracts the electromagnetic force.When the armature held at the neutral position is attracted to the electromagnet side, an electromagnetic force is generated in the electromagnet at a predetermined cycle. A start control means for executing start control for causing the electromagnet to be supplied to the electromagnet from the first current, the second current being smaller than the first current in the process of the start control.
An electromagnetically driven valve for an internal combustion engine, comprising: an exciting current changing unit that changes the current to the current. 3. The electromagnetically driven valve for an internal combustion engine according to claim 1, wherein the exciting current supplied to the electromagnet in the process of the starting control is smaller than the first current from the first current. Second
1. An electromagnetically driven valve for an internal combustion engine, comprising: an exciting current changing means for changing the current into a current.