JPH10288013A - Internal combustion engine equipped with electromagnetic drive valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately open and close a plurality of electromagnetic drive valves through a little consumed electric power in an internal combustion engine loaded with a plurality of electromagnetic drive valves to function as an intake valve or an exhaust valve. SOLUTION: A plurality of electromagnetic drive valves on board an internal combustion engine is closed by applying a valve closing exciting current, and opened by applying a valve opening exciting current after stopping of the supply of valve closing exciting current. At the time of starting the internal combustion engine, starting control is carried out so as to turn a plurality of electromagnetic drive valves in order into a closed state. In this case, the valve closing exciting current IUL, larger in comparison with the usual valve closing exciting current IUS is supplied to the electromagnetic drive valve. In the case where valve opening demand is caused just after the starting control, a valve opening exciting current ILI is supplied in consideration of the influence of residual electromagnetic force to delay the opening of the valve. In the case where the valve opening demand is further caused, a valve opening exciting current ILN is supplied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an internal combustion engine equipped with an electromagnetically driven valve, and more particularly, to an internal combustion engine equipped with a plurality of electromagnetically driven valves functioning as an intake valve or an exhaust valve.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Laid-Open Publication No.
As disclosed in Japanese Patent No. 913, an internal combustion engine equipped with an electromagnetically driven valve is known. A conventional electromagnetically driven valve includes a valve body that functions as an intake valve or an exhaust valve of an 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, when the exciting current is repeatedly supplied to the first electromagnet and the second electromagnet at an appropriate timing, the valve body can be opened and closed with low power consumption by utilizing the simple vibration of the movable portion.

[0007]

As described above, in order to change the conventional electromagnetically driven valve from the non-operating state to the operating state, the valve body held at the neutral position is displaced to the valve closing position. , It is necessary to attract the armature to the first electromagnet. When displacing the valve body held at the neutral position to the valve closing position, it is necessary to supply a large excitation current to the first electromagnet as compared to after the electromagnetically driven valve has shifted to the steady operation state. . Therefore, when the operation of the electromagnetically driven valve is started, a larger amount of power is consumed than after the electromagnetically driven valve has shifted to the steady operation state.

An internal combustion engine may be equipped with a plurality of electromagnetically driven valves. In such an internal combustion engine, the operation of the electromagnetically driven valves may be sequentially started one by one in order to prevent a large amount of electric power from being consumed at one time. In this case, of the plurality of electromagnetically driven valves, the electromagnetically driven valve that has been closed early must maintain the closed state until all other electromagnetically driven valves are closed. . Hereinafter, the above control is referred to as start control.

As described above, during execution of the start control, it is necessary to supply a large amount of exciting current to the electromagnetically driven valve to be shifted to the closed state as compared with the normal state. When such a large exciting current is supplied to the electromagnetically driven valve,
The valve body of the electromagnetically driven valve collides with the valve seat more vigorously than after the electromagnetically driven valve has shifted to the steady operation state. For this reason, during the execution of the start control, a larger vibration is generated in the internal combustion engine with the closing of the valve body than after the electromagnetically driven valve shifts to the steady operation state.

When the above-mentioned large vibration occurs in the internal combustion engine, in order to properly maintain the electromagnetically driven valve already closed at that time in the closed state, the electromagnetically driven valve must be It is necessary to hold the valve body at the valve closing position with a large electromagnetic force. For this reason, during start control,
It is appropriate that the exciting current supplied to each electromagnetically driven valve to maintain the valve body in the valve closing position is made larger than that after all the electromagnetically driven valves have shifted to the steady operation state.

The electromagnetically driven valve starts opening and closing at an appropriate timing after the above-described start control is completed. At this time, the valve body held at the valve closing position stops supplying the exciting current to the first electromagnet and then starts supplying the exciting current to the second electromagnet at an appropriate time, as described above. As a result, the valve can be displaced to the valve opening position. By the way, the first electromagnet generates a residual magnetic field for a certain period after the supply of the exciting current is stopped. As the residual magnetic field disappears more quickly, the valve body of the electromagnetically driven valve is displaced in the valve opening direction earlier after the supply of the exciting current to the first electromagnet is stopped.
On the other hand, the above-mentioned remnant magnetic field becomes
The smaller the exciting current supplied to the electromagnet, the sooner it disappears. Therefore, when the electromagnetically driven valve is displaced from the valve closing position to the valve opening position, the smaller the exciting current supplied to the first electromagnet, the better the responsiveness of the electromagnetically driven valve.

As described above, the electromagnetically driven valve has a different response when the valve body is displaced from the closed position to the open position in accordance with the magnitude of the exciting current for maintaining the valve body in the closed position. Shows sex. Therefore, when the excitation current for holding the valve body is changed during the execution of the start control and after all the electromagnetically driven valves have shifted to the steady operation state, the electromagnetically driven valve realized during the start control is changed. Of the valve opening responsiveness is deteriorated as compared with the valve opening responsiveness normally realized.

As described above, when the electromagnetically driven valve is shifted from the closed state to the open state, the supply of the exciting current to the first electromagnet is stopped, and then the excitation to the second electromagnet is performed at an appropriate time. Current supply is started. The electromagnetic force acting between the second electromagnet and the armature sharply increases as the armature approaches the second electromagnet. For this reason, in order to reduce the power consumption required for driving the electromagnetically driven valve, in the process of shifting the electromagnetically driven valve to the open state, when the armature is sufficiently close to the second electromagnet, the power is supplied to the second electromagnet. It is effective to reduce the exciting current.

However, in the process of shifting the electromagnetically driven valve from the closed state to the open state, the timing at which the armature sufficiently approaches the second electromagnet becomes earlier as the electromagnetically driven valve exhibits excellent valve opening response. . For this reason, immediately after the start control described above, after the supply of the exciting current to the first electromagnet is stopped, the time when the armature sufficiently approaches the second electromagnet is
It is delayed as compared to after the electromagnetically driven valve has shifted to the steady operation state. Therefore, when opening the electromagnetically driven valve immediately after the start control is completed, if the exciting current to the second electromagnet is reduced at the same timing as in the normal case, the armature becomes the second.
Before approaching the electromagnet, the electromagnetic force that draws the armature is reduced, and the electromagnetically driven valve may not operate properly.

The above inconvenience can also be avoided by delaying the timing for reducing the exciting current supplied to the second electromagnet so that the electromagnetically driven valve can operate properly even immediately after the start control. can do. However, according to such measures, after the electromagnetically driven valve shifts to the steady operation state, a period in which power is wasted is always generated. In this regard, the above measures are not appropriate for saving power of the electromagnetically driven valve.

The present invention has been made in view of the above points, and an object of the present invention is to provide an internal combustion engine that can open and close a plurality of electromagnetically driven valves accurately with low power consumption.

[0017]

The above object is achieved by the present invention.
As described in the above, in an internal combustion engine equipped with a plurality of electromagnetically driven valves for driving a valve body that functions as an intake valve or an exhaust valve with electromagnetic force, the electromagnetically driven valve receives a supply of a valve closing excitation current, and Generates an electromagnetic force that urges the body toward the valve closing side,
In addition, start control for generating an electromagnetic force for urging the valve body toward the valve opening side in response to the supply of the valve opening excitation current and for sequentially closing the plurality of electromagnetically driven valves when the internal combustion engine is started. Start-up control means for executing the start-up control, valve-closing excitation current changing means for increasing the valve-closing excitation current supplied to the electromagnetically driven valve as compared with normal times, and each of the electromagnetically driven valve When a valve opening request is issued to the electromagnetically driven valve, the valve closing excitation current supplied to the electromagnetically driven valve for which the valve opening request is made is stopped, and a predetermined value Valve opening processing means for supplying a valve opening exciting current in the pattern of: (a), when the valve opening request is generated immediately after the start control, the predetermined pattern is set to a first pattern, and thereafter, the valve opening request is generated. When the predetermined pattern is
This is achieved by an internal combustion engine equipped with an electromagnetically driven valve provided with a valve opening pattern changing means having the following pattern.

In the present invention, the valve body is energized in the valve closing direction by supplying a valve closing excitation current to the electromagnetically driven valve, and is opened by supplying a valve opening excitation current to the electromagnetically driven valve. It is biased in the valve direction. When starting the internal combustion engine,
The plurality of electromagnetically driven valves are sequentially closed by the start control. During the execution of the start control, a large valve closing excitation current is supplied to the electromagnetically driven valve to hold the valve body in the valve closing position. For this reason, the valve body which has already been closed is properly held at the valve closing position regardless of the vibration accompanying the closing of the other electromagnetically driven valves.

After the start control is completed, a request to open each electromagnetically driven valve is issued at a predetermined timing according to the operating state of the internal combustion engine. When a valve opening request is issued to the electromagnetically driven valve, the supply of the valve closing excitation current to the electromagnetically driven valve is stopped. When the supply of the valve closing excitation current is stopped, the electromagnetic force for urging the valve body in the valve closing direction disappears. Thereafter, when a valve-opening excitation current is generated, an electromagnetic force for urging the valve body in the valve-opening direction is generated, and the electromagnetically driven valve is opened.

Since a large valve closing excitation current is supplied to the electromagnetically driven valve during the execution of the start control, if the electromagnetically driven valve is to be opened immediately after the end of the start control, the excitation current is supplied. Is stopped, an electromagnetic force that urges the valve body in the valve closing direction remains for a relatively long time. Therefore, the valve-opening excitation current is supplied in a similar pattern when a valve-opening request is issued immediately after the start control ends, and when a valve-opening request is issued after the electromagnetically driven valve shifts to a steady operation state. When done
The electromagnetically driven valve may not operate properly. According to the present invention, when a valve opening request is issued immediately after the start control, the valve opening excitation current is considered in consideration of the fact that the electromagnetic force for urging the valve body in the valve closing direction remains for a relatively long time. Are supplied in a first pattern. On the other hand, when a valve opening request is issued after the electromagnetically driven valve has shifted to the steady operation state, the valve is opened in consideration of the fact that the electromagnetic force for urging the valve body in the valve closing direction disappears relatively early. An exciting current is supplied in a second pattern. In this case, the electromagnetically driven valve can always be properly operated with low power consumption.

According to a second aspect of the present invention, there is provided an internal combustion engine equipped with the electromagnetically driven valve according to the first aspect, wherein the first pattern and the second pattern are both open. This is a pattern in which the valve excitation current is changed from a large current to a small current, and a period from when the valve closing excitation current is stopped to when the valve opening excitation current becomes a small current follows the first pattern. Is also achieved by an internal combustion engine equipped with an electromagnetically driven valve, which is longer than when the second pattern is followed.

In the present invention, in the first pattern and the second pattern, the valve-opening excitation current is increased when the valve body approaches the valve-closing position, and the valve body approaches the valve-opening position. The valve opening excitation current is set to be a small current at each stage. When the valve opening excitation current changes as described above, the electromagnetically driven valve is driven with low power consumption. The first pattern is set so that the timing at which the valve-opening excitation current is reduced to a small current is delayed as compared with the second pattern. The first pattern is a pattern used in a situation where the electromagnetic force for urging the valve body in the valve closing direction tends to remain after the supply of the valve closing excitation current is stopped. When the valve opening excitation current changes according to the first pattern and the second pattern, although the electromagnetically driven valve shows a different valve opening response depending on the situation,
The electromagnetically driven valve can always be properly opened and closed.

[0023]

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 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 provided in a cylinder head 13 of the internal combustion engine. The intake port 14 has a valve body 1
2, a valve seat 11 is formed. Intake port 14
When the valve body 12 is separated from the valve seat 11, the conductive state is established, and when the valve body 12 is seated on the valve seat 11, the closed state is established.

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 disposed above the valve shaft 15. A lower retainer 21 is fixed to the upper end of the valve shaft 15. A lower spring 22 is provided between the lower retainer 21 and the lower cap 18. The lower spring 22 holds the lower retainer 21, that is, the plunger 20 and the valve element 1.
2 is urged upward in FIG.

An upper retainer 24 is fixed to the upper end of the plunger 20. An upper spring 26 is provided above the upper retainer 24.
The upper spring 26 moves the upper retainer 24,
That is, the plunger 20 and the valve element 12 are urged downward in FIG. Upper spring 2
6, a cylindrical upper cap 27 is provided. An adjust bolt 28 is provided at the upper end of the upper cap 27. Upper spring 2
The upper end of 6 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 electromagnets 32 and the second electromagnets 38 are held so that a predetermined interval is ensured. The above-described upper cap 27 is attached to the mounting bracket 46 and the mounting bolt 4 so as to contact the upper end surface of the first electromagnet 32.
8 is fixed to the cylinder head 13. On the other hand, the above-described lower cap 18 is fixed inside the cylinder head 13 so as to abut on the vicinity of the lower end of the second electromagnet 38. The neutral position of the armature 30 is adjusted by the first electromagnet 32.
It is adjusted so as to be an intermediate point between the first and second electromagnets 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 element 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 body 12 is maintained in 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 part 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 unit 50 starts a simple vibration at a vibration period of the natural vibration 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 stopped electromagnetically driven valve 10, 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.

FIG. 2 shows a state where the electromagnetic force is generated in the first electromagnet 32 and the second electromagnet 38 so that the above condition is satisfied under the condition that the valve body 12 is held at the neutral position. 2 shows a displacement occurring in the body 12. As shown in FIG. 2, according to the above processing, the first electromagnet 32 and the second electromagnet 3
8 without supplying an extremely large exciting current to the valve element 1.
Until 2 reaches the valve closing position, the amplitude of the valve body 12 can be gradually increased.

After the start of the internal combustion engine is requested, the electromagnetically driven valve 10 of this embodiment displaces the valve body 12 to the valve closing position by the above-described method. For this reason, according to the present embodiment, the power consumption is reduced as compared with the case where a method of changing the valve body 12 to the valve closing position by continuously supplying the exciting current to the first electromagnet 32 is adopted. Thus, the electromagnetically driven valve 10 can be brought into the operating state.

FIG. 3 is a view showing the cylinder head 13 on which the electromagnetically driven valve 10 is mounted, as viewed in the direction of the arrow III shown in FIG. As shown in FIG. 3, the cylinder head 13 is a cylinder head used in a four-cylinder internal combustion engine. Also,
The cylinder head 13 has two intake ports 14 and two exhaust ports 52 corresponding to the # 1 to # 4 cylinders, respectively.

The above-described electromagnetically driven valve 10 is disposed in all the intake ports 14 formed in the cylinder head 13. In addition, all the exhaust ports 52 formed in the cylinder head 13 are provided with electromagnetically driven valves having the same configuration as the electromagnetically driven valve 10 shown in FIG. 1 except for the diameter of the valve body. Hereinafter, the electromagnetically driven valve disposed at the exhaust port 52 and the electromagnetically driven valve 10 disposed at the intake port 14 are collectively referred to as the electromagnetically driven valve 10.

As described above, in order to bring the electromagnetically driven valve 10 into the operating state, an exciting current is supplied to the first electromagnet 32 and the second electromagnet 38 at a predetermined cycle to displace the valve body 12 to the valve closing position. Need to be done. After the electromagnetically driven valve 10 has shifted to the steady operating state, the operating state of the electromagnetically driven valve 10 is properly adjusted by supplying sufficient power to the first electromagnet 32 and the second electromagnet 38 to compensate for the sliding loss. Can be maintained. On the other hand, in order to increase the amplitude of the valve body 12, it is necessary to supply larger power to the first electromagnet 32 and the second electromagnet 38. For this reason,
In the process of displacing the valve body 12 of the electromagnetically driven valve 10 from the neutral position to the closed position, a large amount of power is consumed as compared to after the electromagnetically driven valve 10 has shifted to the steady operation state.

It is not preferable that an extremely large amount of electric power is consumed by the electromagnetically driven valve 10 at the time of starting the vehicle from various viewpoints such as the startability of the internal combustion engine and the capacity and durability of the battery. For this reason, in the present embodiment, after the start of the internal combustion engine is requested, the electromagnetically driven valves 10 disposed on the cylinder head 13 are sequentially closed one by one or two or three sequentially. You are going to. According to the above control method, it is possible to prevent a very large amount of electric power from being consumed in a short time when the internal combustion engine is started. Hereinafter, as described above, the plurality of electromagnetically driven valves 10 are sequentially set to one.
The control for closing the valves one by one is called start control.

In the process of displacing the valve body 12 from the neutral position to the closed position, a large exciting current is supplied to the electromagnetically driven valve 10 as described above. When the electromagnetically driven valve 10 is driven by such a large exciting current, the valve body 12 reaches the valve closing position with a larger displacement speed than after the electromagnetically driven valve 10 has shifted to a steady operation state. . For this reason,
During the execution of the start control, a larger vibration is generated in the cylinder head 13 when the valve body 12 reaches the valve closing position than after the electromagnetically driven valve 10 has shifted to the steady operation state.

After the start control is started, the electromagnetically driven valve 10 that has been closed before the other electromagnetically driven valves 10 is closed until all other electromagnetically driven valves 10 are closed. Must be maintained. In order to maintain the closed state properly when the large vibration occurs in the cylinder head 13 as described above, the electromagnetic force in the valve closing direction generated by the electromagnetically driven valve 10 is increased as compared with the normal state. Need to be kept.

FIG. 4A shows the waveform of the exciting current supplied to the upper coil 34 under the condition that the valve body 12 should be kept closed. Figure 4 (A) waveform shown by a solid line in is excitation current I _UI of waveform supplied during the starting control execution. On the other hand, the waveform shown by the broken line in FIG. 4A is the waveform of the exciting current I _UN supplied after the electromagnetically driven valve 10 has shifted to the steady operation state.

As shown in FIG. 4A, in this embodiment, the exciting current supplied after the electromagnetically driven valve 10 has shifted to the steady operation state is set to a relatively small current I _UN. Thus, the exciting current supplied during execution of the start control is set to a relatively large current _IUI . When the exciting current changes as described above during and after the start-up control, it is possible to prevent the exciting current supplied to the upper coil 34 from becoming an unnecessarily large value after the electromagnetically driven valve 10 shifts to the steady operation state. At the same time, the valve body 12
Large electromagnetic force can be generated in a direction for urging the valve in the valve closing direction. For this reason, according to the system of the present embodiment, it is possible to prevent the valve body 12 from being unduly opened during the execution of the start control, and to realize excellent power saving characteristics.

The waveform shown by the solid line in FIG.
_The valve element 12 realized when the exciting current I _UI has disappeared to ₀
Shows the displacement of The waveform shown by the broken line in FIG. 4B shows the displacement of the valve body 12 realized when the exciting current I _UN disappears at the time t ₀ . While the exciting current I _UI or I _UN flows through the upper coil 34, the first electromagnet 32
An electromagnetic force is generated according to the exciting current _IUI or _IUN . Further, the first electromagnet 32 is provided with an exciting current I _UI or I _UN
For a certain period after disappearance of the magnetic field, an electromagnetic force (hereinafter, referred to as a residual electromagnetic force) caused by the residual magnetic field is generated. Valve body 12
Starts to be displaced in the valve opening direction after the residual electromagnetic force has disappeared.

The residual electromagnetic force of the first electromagnet 32 disappears earlier as the exciting current supplied to the first electromagnet is smaller. Therefore, the residual electromagnetic force of the first electromagnet 32 is energized current supplied to the upper coil 34 when was I _UI, the exciting current remain long time as compared with the case was I _UN. Accordingly, as shown in FIG. 4 (B), when the exciting current that has disappeared at time t ₀ is I _UN , the valve body 12 is immediately displaced in the valve opening direction. If the excitation current that has disappeared at time t ₀ is I _UN , then the valve is displaced in the valve opening direction after a certain period of time has elapsed.

The waveform shown by the solid line in FIG. 4C is supplied to the lower coil 40 of the electromagnetically driven valve 10 when the opening of the electromagnetically driven valve 10 is requested immediately after the start control is completed. 3 shows a waveform of the exciting current _ILI . FIG.
The waveform shown by the broken line in (C) indicates that when a request to open the electromagnetically driven valve 10 is made after transition to the steady operation state,
3 shows a waveform of an exciting current I _LN supplied to a lower coil 40 of the electromagnetically driven valve 10.

As described above, according to the electromagnetically driven valve 10, after the supply of the exciting current to the first electromagnet 32 is stopped, the supply of the exciting current to the second electromagnet 38 is started at an appropriate time, whereby the movable portion The valve body 12 can be displaced to the valve-open position by compensating for the sliding loss caused by the sliding of the valve 50. By the way, the electromagnetic force acting between the second electromagnet 38 and the armature 30 rapidly increases as the distance between the two decreases. For this reason, the armature 30 is sufficiently in the second electromagnet 3
After approaching 8, even if the exciting current supplied to the second electromagnet 38 is set to a sufficiently small value, the electromagnetic force required for the operation of the electromagnetically driven valve 10 can be obtained.

As shown in FIG. 4C, the exciting current I supplied to the electromagnetic coil 10 after shifting to the steady operation state.
_LN is controlled to be the first current I _{1 at} time t ₁ , and then to the second current I ₂ (<I ₁ ) at time t ₃ . Time t ₁ and time t _3, based on the time t ₀ when the supply of the exciting current I _UN to the upper coil 34 is stopped, respectively, the time the valve body 12 reaches the vicinity of the neutral position, and the valve body 12 Is determined as the time at which the valve reaches the valve opening position.

Similarly, the excitation current I _LI supplied to the electromagnetic coil 10 immediately after the end of the start control is set to the first current I _{1 at} time t ₂ , and thereafter, the second current I ₂ is supplied at time t ₄ . (<
I ₁ ) is controlled. Time t ₂ and time t
₄ is based on the time t _{0 at} which the supply of the exciting current I _UI to the upper coil 34 is stopped, and considers that the timing at which the valve body 12 starts to be displaced in the valve opening direction due to the influence of the residual electromagnetic force is delayed. Then, the time at which the valve body 12 reaches the vicinity of the neutral position and the time at which the valve body 12 reaches the valve opening position are respectively defined.

The electromagnetically driven valve 1 immediately after the start control is completed
0 and the electromagnetically driven valve 1 after shifting to the steady operating state
0, the exciting current I that changes the current value in the above pattern
When _LI and I _LN are supplied, while the armature 30 even under any circumstances and the second electromagnet 38 is separated from the exciting current is controlled to the first current I _1. Further, even under any circumstances, the exciting current is reduced from the first current I ₁ to the current I ₂ to the second according to the armature 30 and the second electromagnet 38 approaches. Therefore, according to the system of the present embodiment,
Immediately after the start control is completed and after the electromagnetically driven valve 10 has shifted to the steady operation state, the valve body 12
Can be reliably displaced to the valve closing position with low power consumption.

FIG. 5 is executed in the electromagnetically driven valve 10 to set the pattern of the exciting current supplied to the lower coil 40 to either the pattern of the exciting current I _LI or the pattern of the exciting current I _LN depending on the situation. 3 is a flowchart illustrating an example of a control routine. The routine shown in FIG. 5 is a periodic interruption routine that is started every predetermined time. When this routine is started, first, the process of step 100 is executed.

In step 100, it is determined whether or not the electromagnetically driven valve 10 has shifted to a steady operation state. In this step 100, specifically, it is determined whether or not the flag XNORMAL is in an ON state. Flag XNORM
AL is a flag that is turned on after the electromagnetically driven valve 10 shifts to a steady operation state, as described later. As a result of the above determination, if it is determined that the electromagnetically driven valve 10 has already shifted to the steady operation state, the current routine is terminated without any further processing. On the other hand, if it is determined that the electromagnetically driven valve 10 has not yet shifted to the steady operation state, the process of step 102 is executed next.

In step 102, it is determined whether a request to open the electromagnetically driven valve 10 has been issued. As a result, if it is determined that a request to open the electromagnetically driven valve 10 has not been issued, the current routine is terminated without any further processing. On the other hand, if it is determined that a request to open the electromagnetically driven valve 10 has occurred, the process of step 104 is performed next.

In step 104, it is determined whether or not the valve opening request detected in the current processing cycle is the first request after the start control is completed. In this step 104, specifically, it is determined whether or not the flag XINIT is in an off state. The flag INIT is a flag that is turned on when the first valve opening request is made after the start control ends. Therefore, as a result of the above determination, XIN
When it is determined that IT = OFF is established, it can be determined that the current valve opening request is a request that has been generated only after the start control has been completed. In this case, the process of step 106 is performed next.

[0058] At step 106, processing for the pattern of the excitation current I _LI indicating a pattern of supplying the exciting current to the lower coil 40 in FIG 4 (C) is performed. After the process of step 106 is performed, the lower coil 40
, The excitation current is supplied in a pattern of the excitation current I _LI , that is, in a pattern in which the effect of the residual electromagnetic force remaining in the first electromagnet 32 is considered. When the process of step 106 is completed, the process of step 108 is performed next.

In step 108, a process for turning on the flag XINIT is executed. When the process of step 108 ends, the current routine ends. After the processing in step 108 is executed, when a request to open the electromagnetically driven valve 10 is made again, this time, in step 1
04, XINIT = OFF is not established, that is,
It is determined that the present valve opening request is not the first request after the start control is completed. In this case, the process of step 110 is performed after step 108.

In step 110, a process is executed in which the pattern of the exciting current supplied to the lower coil 40 is set to the pattern of the exciting current I _LN shown in FIG. 4C. After the process of step 110 is performed, the lower coil 40
In this case, the excitation is performed in the pattern of the excitation current I _LN , that is, in the pattern on the assumption that the supply of the excitation current to the first electromagnet 32 is stopped and then the valve body 12 starts to be displaced promptly in the valve opening direction. Current is supplied. When the process of step 110 is completed, the process of step 112 is performed next.

At step 112, the flag XNORMA
A process for turning L on is executed. This step 11
When the processing of step 2 is completed, the current routine is terminated.
After the processing of step 112 is executed, every time the routine is started, the XN
ORMAL = ON is satisfied, that is, the electromagnetically driven valve 1
It is determined that 0 has already shifted to the steady operation state. Therefore, the pattern of the exciting current supplied to the lower coil 40 is thereafter maintained as the exciting current _ILN .

According to the above-described processing, when the opening of the electromagnetically driven valve 10 is required immediately after the start control is completed, and after the electromagnetically driven valve 10 shifts to the steady operation state, the opening of the electromagnetically driven valve 10 is required. In this case, the excitation current supplied to the lower coil 40 may be controlled in an appropriate pattern for realizing excellent power saving characteristics and for properly opening and closing the electromagnetically driven valve 10. it can. Therefore, according to the system of the present embodiment, all the electromagnetically driven valves 10 can be properly opened and closed with small power consumption.

In the above-described embodiment, the excitation current _ILI immediately after the start control is set to the first current in consideration of the fact that the residual electromagnetic force is likely to remain in the first electromagnet 32 immediately after the end of the start control. The time when the current I ₁ or the second current I ₂ changes is delayed with respect to the time when a similar change occurs in the normal exciting current I _LN , but the pattern of the exciting current I _LI is not limited to this. Not something.

[0064] That is, the pattern of the excitation current I _LI immediately after completion of startup control, exciting the exciting current I _LI is normal current I
The first current I ₁ may be set to be maintained for a long period of time as compared with the _LN. In addition, the exciting current I _LI immediately after the start control ends.
_May be set so that the exciting current I _LI generates a larger peak current than the normal exciting current I _LN . If the exciting current I _LI is set as described above, the electromagnetic force for urging the valve body 12 in the valve opening direction is set to a large value when the opening of the electromagnetically driven valve 10 is required immediately after the end of the start control. This makes it possible to provide the electromagnetically driven valve 10 with excellent valve opening response regardless of the presence of the residual electromagnetic force.

In the above embodiment, the exciting currents I _UI and I _UN supplied to the upper coil 34 are replaced with the exciting current I _LI supplied to the lower coil 40 in the “valve-closing exciting current” of the first embodiment. And I _LN respectively correspond to the “valve-opening exciting current” of the first embodiment, and the valve bodies 12 of all the electromagnetically driven valves 10 are sequentially displaced one by one from the neutral position to the closed position. Accordingly, the “start control means” according to claim 1 is configured such that the electromagnetically driven valve 10 supplies either the excitation current I _UI or I _UN to the first electromagnet 32 and the second electromagnet 38 By supplying either one of the excitation currents I _LI and I _LN , the “valve closing excitation current changing means” and the “valve opening processing means” according to claim 1,
Further, the "valve opening pattern changing means" according to claim 1 is realized by the electromagnetically driven valve 10 executing the processing of steps 100 to 112, respectively.

Further, in the above embodiment, the first current I _{1 corresponds} to the “large current” according to the second aspect, and the second current I _{2 corresponds} to the “small current” according to the second aspect. also, the period of time t ₀ ~t ₃ shown in FIG. 4, and, time t ₀ ~t ₄
Corresponds to the “period from the stop of the valve-closing excitation current to the reduction of the valve-opening excitation current to a small current”.

[0067]

As described above, according to the first and second aspects of the present invention, when the valve opening request is issued immediately after the start control is completed, and when the electromagnetically driven valve is in the steady operation state. When a valve opening request is made after the shift, the valve opening excitation current can be supplied to the electromagnetically driven valve in an appropriate pattern. Therefore, according to the present invention, the plurality of electromagnetically driven valves can always be properly opened and closed with low power consumption.

[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. 2 is a diagram illustrating a displacement generated in a valve body of an electromagnetically driven valve illustrated in FIG. 1 in a process in which start control is performed in the system of the present embodiment.

FIG. 3 is a diagram showing a cylinder head on which the electromagnetically driven valve according to the present embodiment is mounted, as viewed in the direction of arrow III shown in FIG.

FIG. 4 (A) is an illustration showing an exciting current I _UI supplied to the first electromagnet during or immediately after the start control is executed, and an excitation current I _UI supplied to the first electromagnet after the electromagnetically driven valve shifts to a steady operation state. _Is a waveform of the exciting current I _UN to be applied. FIG. 4B shows the displacement of the valve body realized when the excitation current I _UI supplied immediately after the start control disappears at time t ₀ , and the supply after the electromagnetically driven valve shifts to a steady operation state. Excitation current I
_UN is a diagram showing a displacement of the valve body which is realized when the disappeared time t _0. FIG. 4C shows the excitation current I _LI supplied to the second electromagnet during or immediately after the start control is executed, and the excitation current supplied to the second electromagnet after the electromagnetically driven valve has shifted to the steady operation state. It is a waveform of _ILN .

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

[Explanation of symbols]

Reference Signs List 10 electromagnetically driven valve 12 valve element 13 cylinder head 14 intake port 32 first electromagnet 34 upper coil 36 upper core 38 second electromagnet 40 lower coil 42 lower core 52 exhaust port I _UL , I _UN , I _LI , I _LN exciting current I ₁ Current I ₂ Second current

Claims (2)

[Claims] 1. An internal combustion engine equipped with a plurality of electromagnetically driven valves for driving a valve body functioning as an intake valve or an exhaust valve by electromagnetic force, wherein the electromagnetically driven valve receives a supply of a valve-closing excitation current, and An electromagnetic force for urging the valve body to the valve closing side is generated, and an electromagnetic force for urging the valve body to the valve opening side in response to the supply of the valve opening exciting current is generated, and at the time of starting the internal combustion engine, Starting control means for executing start control for sequentially closing the plurality of electromagnetically driven valves; and increasing the valve closing excitation current supplied to the electromagnetically driven valves during execution of the start control as compared with normal times. Valve closing excitation current changing means, when a valve opening request is issued to each of the electromagnetically driven valves, stopping the valve closing excitation current supplied to the electromagnetically driven valve where the valve opening request is generated, and The valve is opened in a predetermined pattern with respect to the electromagnetically driven valve for which the valve opening request has occurred. Valve opening processing means for supplying a magnetic current, the predetermined pattern is set to a first pattern when the valve opening request is generated immediately after the start control, and the predetermined pattern is set when the valve opening request is further generated. An internal combustion engine equipped with an electromagnetically driven valve, comprising: valve opening pattern changing means for setting the pattern as a second pattern. 2. The internal combustion engine equipped with the electromagnetically driven valve according to claim 1, wherein both the first pattern and the second pattern are patterns that change the valve opening excitation current from a large current to a small current. In addition, after the valve closing excitation current is stopped, the period until the valve opening excitation current becomes a small current is longer in the case of following the first pattern than in the case of following the second pattern. An internal combustion engine equipped with an electromagnetically driven valve.