JP3548667B2 - Electromagnetic drive valve for internal combustion engine - Google Patents

Description

[0001]
TECHNICAL 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]
[Prior art]
2. Description of the Related Art An electromagnetically driven valve for an internal combustion engine has been conventionally known, as disclosed in, for example, Japanese Patent Application Laid-Open No. 59-213913. The conventional electromagnetically driven valve includes a valve body functioning 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.
[0003]
A first electromagnet and an upper spring are disposed 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.
[0004]
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 is a natural vibration period T determined by the mass M of the movable portion and the spring constant K of the upper spring and the lower spring.₀= 2π√ (M / K). Therefore, in the above-described conventional apparatus, after the supply of the exciting current to the first electromagnet is stopped, the predetermined time “T₀It can be determined that the movable portion has reached the vicinity of the second electromagnet at the point of time when "/ 2" has elapsed.
[0006]
When an exciting current is supplied to the second electromagnet when the movable section reaches the vicinity of the second electromagnet, an electromagnetic force that draws the armature toward the second electromagnet can be generated. 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 element 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.
[0007]
In the above-mentioned 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 to the first electromagnet side. Therefore, when the conventional electromagnetically driven valve draws the armature held at the neutral position to the first electromagnet, the first electromagnet and the second electromagnet apply the above-described natural oscillation period T to the first electromagnet.₀Is set as one cycle, the start control for supplying the exciting current alternately is executed.
[0008]
According to the above-described start control, the movable portion is displaced toward the first electromagnet by gradually increasing the amplitude of the movable portion without supplying an extremely large exciting current to the first electromagnet and the second electromagnet. Can be done. Therefore, according to the conventional electromagnetically driven valve, the movable portion held at the neutral position can be drawn toward the first electromagnet with low power consumption.
[0009]
[Problems to be solved by the invention]
However, the above-described natural oscillation period T₀Is a cycle realized when the movable portion makes a simple vibration using 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, the electromagnetic force is used to drive 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 is substantially equal to the natural vibration period T₀Matches. Therefore, during the steady operation, the vibration period T of the movable part is substantially changed to the natural vibration period T.₀However, no inconvenience arises.
On the other hand, in the above-described start control process, the electromagnetic force is used to forcibly increase the amplitude generated in the movable portion due to the simple vibration. In this case, the vibration period T of the movable part is equal to the natural vibration period T₀Shows a tendency to lengthen as compared to.
[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 the two decreases. For this reason, the tendency of the vibration cycle T to be prolonged in the process of the starting control 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 portion. It becomes more noticeable.
[0012]
As described above, in the electromagnetically driven valve, during the execution of the start control, particularly at the stage where the amplitude of the movable portion is small, the movable portion has the natural oscillation period T.₀A phenomenon occurs in which the vibration occurs with a longer period T than that of FIG. 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 apparatus is not always optimal for saving power of the electromagnetically driven valve.
[0013]
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 initially driving an armature held at a neutral position. Aim.
[0014]
[Means for Solving the Problems]
An object of the present invention is to provide a valve element constituting an intake valve or an exhaust valve of an internal combustion engine, an armature that operates together with the valve element, and the valve element and the armature facing a neutral position. An electromagnetically driven valve of an internal combustion engine, comprising: a biasing spring member; and an electromagnet that generates an electromagnetic force that draws the armature.
When pulling the armature held at the neutral position toward the electromagnet, a start control unit that executes start control for generating an electromagnetic force in a predetermined cycle on the electromagnet,
In the process of the starting control, an exciting current supplied to the electromagnet when displacing the armature to the electromagnet side,When the amplitude of the armature reaches a sufficiently large value,From the first currentTheExciting current changing means for changing to a second current smaller than the first current;
This is achieved by an electromagnetically driven valve of an internal combustion engine comprising:
[0017]
In the present invention, the armature held at the neutral position is displaced toward the electromagnet when the start control is executed. In the process of the 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 prolongation appearing in the vibration period of the armature is suppressed. On the other hand, after the armature amplitude has increased, 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 cycle of the armature does not tend to be significantly prolonged. For this reason, the oscillation cycle of the armature during the start control 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.
[0018]
Further, the above object is achieved by providing a valve element constituting an intake valve or an exhaust valve of an internal combustion engine, an armature operating with the valve element, and directing the valve element and the armature to a neutral position. An electromagnetically driven valve of an internal combustion engine, comprising: a spring member that biases and biases, and an electromagnet that generates an electromagnetic force that draws the armature.
When pulling the armature held at the neutral position toward the electromagnet, a start control unit that executes start control for generating an electromagnetic force in a predetermined cycle on the electromagnet,
In the process of the start control, the predetermined cycle, a cycle changing means for approaching the natural oscillation cycle from a cycle larger than the natural oscillation cycle of the armature,
In the process of the starting control, an exciting current supplied to the electromagnet when displacing the armature to the electromagnet side,When the amplitude of the armature reaches a sufficiently large value,From the first currentTheExciting current changing means for changing to a second current smaller than the first current;
This is also achieved by an electromagnetically driven valve of an internal combustion engine having:
[0019]
In the present invention, during the execution of the start control, (1) the control for suppressing the fluctuation of the oscillation cycle of the armature by changing the exciting current supplied to the electromagnet, and (2) the cycle for supplying the exciting current to the electromagnet. By making the change, both the period in which the electromagnet generates the electromagnetic force and the control to match the amplitude period of the armature are executed. In this case, the armature can be efficiently displaced to the vicinity of the electromagnet by the start control while suppressing power consumption to a necessary minimum.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an overall configuration diagram of an electromagnetically driven valve 10 according to one embodiment of the present invention. The electromagnetically driven valve 10 includes a valve element 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. The intake port 14 is turned on when the valve body 12 is separated from the valve seat 11, and is shut off when the valve body 12 is seated on the valve seat 11.
[0021]
A valve shaft 15 is fixed to the valve body 12. The valve shaft 15 is held by a valve guide 16 so as to be slidable in the axial direction. The valve guide 16 is supported by the cylinder head 13. The lower cap 18 of the electromagnetically driven valve 10 is fixed to the valve guide 16. A plunger 20 made of a nonmagnetic material is fixed to an upper portion of the valve shaft 15.
[0022]
A lower retainer 21 is fixed to the upper end of the valve shaft 15. Between the lower retainer 21 and the lower cap 18, a lower spring 22 that generates a biasing force in a direction to separate the lower retainer 21 and the lower cap 18 is provided. The lower spring 22 urges the lower retainer 21, that is, the plunger 20 and the valve body 12, upward in FIG.
[0023]
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 urges the upper retainer 24, that is, the plunger 20 and the valve body 12 downward in FIG.
A cylindrical upper cap 27 is arranged 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.
[0024]
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, a first 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 hold the plunger 20 slidably at the center thereof.
[0025]
An outer cylinder 44 is provided on the outer periphery of the first electromagnet 32 and the second electromagnet 38. The outer cylinder 44 holds both the first electromagnet 32 and the second electromagnet 38 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 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 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.
[0026]
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.
[0027]
Therefore, according to the electromagnetically driven valve 10, by supplying an appropriate excitation 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. 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 portion 50 can be continued until the armature 30 comes into contact with 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 exciting current to the upper coil 34, the valve body 12 can be displaced to the valve closing position.
[0028]
When the valve element 12 is maintained at the valve closing position, the upper spring 26 and the lower spring 22 generate 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.
[0029]
The period T of the simple vibration is a natural vibration period T determined by the mass M of the movable portion 50 and the spring constants K of the upper spring 26 and the lower spring 22.₀= 2π√ (M / K). Therefore, in the electromagnetically driven valve 10, after the supply of the exciting current to the upper coil 34 is stopped, the predetermined time “T₀It can be determined that the armature 30 has reached the vicinity of the lower core 42 at the point of time when "/ 2" has elapsed.
[0030]
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 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.
[0031]
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 closed position to the fully opened position with low power consumption. be able to.
[0032]
When the supply of the exciting current to the lower core 42 is stopped after the armature 30 contacts the lower core 42, the movable portion 50₀The simple oscillation starts in the simple oscillation period. As a result, the armature 30 is displaced upward in FIG. Thereafter, when the exciting current is repeatedly supplied to the upper coil 34 and the lower coil 40 at an appropriate timing, the valve element 12 can be appropriately opened and closed with small power consumption.
[0033]
As described above, in order to operate the stopped electromagnetically driven valve 10, it is necessary to displace the armature 30 held at the neutral position until the armature 30 once comes into contact with the upper core 36 (or the lower core 42). The above displacement can also be generated by continuously supplying a sufficiently large exciting current to the upper coil 34, for example. 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.
[0034]
When the movable portion 50 of the electromagnetically driven valve 10 is released from the neutral position and the constraint is released, the above-described natural vibration period T₀Starts a simple vibration with. Further, 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, the first electromagnet generates an electromagnetic force, and the movable part 50 The second electromagnet 38 can be grown by generating an electromagnetic force in the process of being displaced toward.
[0035]
Therefore, when the electromagnetic drive valve 10 is started, if an electromagnetic force is generated in the first electromagnet 32 and the second electromagnet 38 so that the above condition is satisfied, a large exciting current is applied to the upper coil 34 and the lower coil 40. Without supplying, a large amplitude can be given to the movable section 50. If the amplitude of the movable section 50 is increased until the armature 30 contacts the upper core 36 (or the lower core 42), the electromagnetically driven valve 10 can be started with less power consumption.
[0036]
When the start is required, the electromagnetically driven valve 10 of this embodiment alternately supplies an exciting current to the upper coil 34 and the lower coil 40 with a predetermined oscillation cycle T as one cycle, so that the solenoid drive valve 10 is set to the neutral position. The held armature 30 is drawn toward the upper core 36 (or the lower core 42). 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 section 50. Hereinafter, the characteristic portion of the electromagnetically driven valve 10 will be described with reference to FIGS.
[0037]
FIG. 2A shows a displacement generated in the valve body 12 when the above-described start control is performed in the electromagnetically driven valve 10. 2 (B) and 2 (C) show that the supply period T of the exciting current is different from the natural oscillation period T of the movable section 50.₀The waveforms of the exciting current supplied to the upper coil 34 or the lower coil 40 are shown in the case where. FIGS. 2C and 2D 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.
[0038]
When the above-described start control is performed, the supply cycle T of the exciting current is set to the natural oscillation cycle T₀It is conceivable to make it match. However, the natural vibration period T of the movable part 50₀Is 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 the 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 execution of the start control, the movable section 50₀It vibrates at a different cycle.
[0039]
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 causes the spring force of the upper spring 26 and the lower spring 22 to change the displacement of the movable portion 50 When the speed is to be reduced, it acts to prevent the displacement speed from lowering 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. For this reason, when the start control is being executed, the vibration period T of the movable portion 50 is, specifically, as shown in FIG.₀Is longer than that of
[0040]
Further, the tendency of the prolongation appearing in the vibration period T of the movable portion 50 is smaller as the electromagnetic force acting between the first electromagnet 32 or the second electromagnet 38 and the armature 30 is stronger, and the smaller the electromagnetic force is, It becomes remarkable. 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 period T to be prolonged in the process of the start control is remarkable in a region where the amplitude of the movable section 50 is small, and disappears as the amplitude of the movable section 50 increases.
[0041]
FIG. 3 is a diagram illustrating a relationship between the number of vibrations k generated in the movable unit 50 and the vibration period T of the movable unit 50 after the start control is started. 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 section 50 becomes longer as the number of vibrations k increases after the start control is started.₀The natural oscillation period T₀Shows a tendency to approach.
[0042]
As shown in FIGS. 2 (D) and 2 (E), in the electromagnetically driven valve 10 of the present embodiment, in consideration of the fact that the oscillation period T of the movable portion 50 changes as described above in the process of starting control, Natural vibration period T₀Correction value δ_kIs added to the cycle “T₀+ Δ_k"Is one cycle, and an exciting current is supplied to the upper coil 34 and the lower coil 40.
[0043]
FIG. 4 shows a correction term δ used for correcting the supply cycle of the exciting current._k1 shows an example of a map that is referred to when obtaining a. As shown in FIG._kChanges to a smaller value as the number k of vibrations generated in the movable unit 50 increases after the start control is started. According to the map shown in FIG. 4, the excitation current supply period T₀+ Δ_kAfter the start control is started, as the number of vibrations k of the movable unit 50 increases, the natural vibration period T₀Can be approached.
[0044]
Further, as described above, the tendency of the prolongation appearing in 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 variation width generated in the oscillation period T of the movable section 50 during the execution of the start control, a large excitation current is supplied to the upper coil 34 and the lower coil 40 when the amplitude of the movable section 50 is small, and After the amplitude of the movable section 50 increases, it is appropriate to supply a small exciting current to the upper coil 34 and 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.
[0045]
As shown in FIG. 2D, 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 I at a stage where the amplitude of the movable portion 50 is small._LIs set to At the stage where the amplitude of the movable section 50 reaches a sufficiently large value, the exciting current becomes the first current I_LSecond current I smaller than₂Is set to For this reason, according to the electromagnetically driven valve 10, it is possible to prevent the vibration period T of the movable portion 50 from changing significantly during the execution of the start control, and to complete the start control with low power consumption. .
[0046]
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.
In step 100, it is determined whether or not the flag XCLOSE is on. 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. If it is determined in step 100 that XCLOSE = ON has already been 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.
[0047]
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.
[0048]
In step 104, a process of setting the supply period T of the exciting current based on the count value of the counter k is executed. In step 104, specifically, the correction term δ corresponding to the count value of the counter k with reference to the map shown in FIG._kAnd the natural oscillation period t₀The correction term δ_kIs stored as the supply cycle T. When the process of step 104 is completed, the process of step 106 is executed.
[0049]
In step 106, a process of supplying the exciting current I to the upper coil 34 is executed. The exciting current I is converted into a first current I_LIs set to When the process of step 106 is completed, the process of step 108 is executed next.
In step 108, it is determined whether or not half the period “T / 2” of the supply period T has elapsed after the excitation current was 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, when it is determined that the predetermined time T / 2 has elapsed, the process of step 110 is performed next.
[0050]
In step 110, a process of stopping the supply of the exciting current to the upper coil 34 is executed. When the process of step 110 is performed, the process of step 112 is performed next.
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 of step 114 is performed next.
[0051]
In step 114, it is determined whether or not half the period "T / 2" of the supply period T has elapsed after the excitation current was started to be supplied to the lower coil 40. 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.
[0052]
In step 116, a process of stopping the supply of the exciting current to the lower coil 40 is executed. After the process of step 116 is performed, the process of step 118 is performed next.
In step 118, the count value k of the counter k₀Is a predetermined value k₀It is determined whether or not this is the case. As a result of the above determination, k ≧ k₀Does not hold, after the start-up control is started, the number of vibrations of the movable portion 50 causes the exciting current I to still be the first current I_LFrom the second current I_SIt is determined that the number of times to change to has not been reached. In this case, the process of step 120 is executed next. On the other hand, already k ≧ k₀Is satisfied, the exciting current I is changed to the second current I._SIt is determined that the time has come. In this case, the process of step 122 is executed next.
[0053]
In step 120, the exciting current I is changed to the first current I_LIs 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_SIs performed. When the process of step 122 is completed, the process of step 124 is executed next.
[0054]
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. If k ≧ N is not satisfied as a result of the above determination, it can be determined that the number of vibrations of the movable unit 50 is still insufficient. In this case, the processing after step 102 is executed again. 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 process of step 126 is performed next.
[0055]
At step 126, the flag XCLOSE is turned on. When the process of step 126 ends, the current routine ends.
According to the above-described processing, after the start control is started, the predetermined number k₀The excitation current I is changed to the first current I_LAnd the number of vibrations of the movable part 50 is a predetermined number k₀As described above, the exciting current I is changed to the second current I_S(<I_L). For this reason, according to the electromagnetically driven valve 10 of the present embodiment, it is possible to reduce the width of the fluctuation occurring in the vibration cycle of the movable section 50 during the execution of the start control.
[0056]
Further, 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, after the start of the electromagnetically driven valve 10 is requested, the electromagnetically driven valve 10 can be extremely efficiently shifted to the steady operation state with little power consumption.
By the way, in the above embodiment, the supply period T of the exciting current is set to the natural oscillation period T.₀The natural oscillation period T₀And the exciting current I is reduced to the first current I._LFrom the second current I_SAlthough the control for reducing the number of times is executed together, the present invention is not limited to this, and these controls may be executed independently of each other.
[0057]
Further, in the above embodiment, the excitation current is changed in two stages during the execution of the start control, but the present invention is not limited to this, and the excitation current is changed to the first current I._LFrom the second current I_SUp to this step 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 “start control means” according to claim 1 and claim 2 corresponds to the “electromagnet” according to claim 2, and the electromagnetically driven valve 10 executes the processing in steps 106 to 116 described above. By executing the processing of steps 102 and 104 described above.2The described “period changing means” is realized. Further, in the above embodiment, the electromagnetically driven valve 10 performs the processing of steps 118 to 122, thereby making the claims.1And the claims2The described "exciting current changing means" is realized respectively.
[0058]
【The invention's effect】
As described above, according to the first aspect of the present invention,The oscillation period of the armature generated during the start control can be maintained substantially constant while the exciting current supplied to the electromagnet is suppressed to a necessary minimum when the armature is displaced to the electromagnet side during the start control. Therefore, according to the electromagnetically driven valve of the internal combustion engine according to the present invention, excellent power saving characteristics can be realized.
[0059]
According to the invention described in claim 2,The beginningIn the process of the dynamic control, it is possible to execute both the control for keeping the vibration period of the armature constant and the control for making the period in which the electromagnet generates the electromagnetic force coincide with the vibration period of the armature. 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 a displacement generated in a valve body when start control is performed in the electromagnetically driven valve of the present embodiment.
FIG. 2B shows that the supply cycle of the exciting current is set to the natural oscillation cycle T of the movable part.₀FIG. 7 is a diagram illustrating a waveform of an exciting current supplied to an upper coil when the values are matched.
FIG. 2C shows that the supply cycle of the exciting current is set to the natural oscillation cycle T of the movable part.₀FIG. 9 is a diagram illustrating a waveform of an exciting current supplied to a lower coil when the values are made to coincide with each other.
FIG. 2D is a diagram illustrating a waveform of an exciting current supplied to the upper coil when the start control is performed in the electromagnetically driven valve of the present embodiment.
FIG. 2E is a diagram illustrating a waveform of an exciting current supplied to the 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.
FIG. 4 shows a correction term δ when starting control is performed in the electromagnetically driven valve of the present embodiment._kIs an example of a map that is referred to in order to obtain a map.
FIG. 5 is a flowchart of an example of a control routine executed in the electromagnetically driven valve of the embodiment.
[Explanation of symbols]
10 Electromagnetic drive valve
12 valve body
20 plunger
30 Armature
32 1st electromagnet
34 upper coil
36 Upper core
38 2nd electromagnet
40 lower coil
42 Lower Core

Claims (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. An electromagnet to be generated, and an electromagnetically driven valve of an internal combustion engine comprising:
When pulling the armature held at the neutral position toward the electromagnet, start control means for executing start control for generating an electromagnetic force at a predetermined cycle on the electromagnet,
In the course of the starting control, the excitation current supplied to the electromagnet when displacing the armature to the electromagnet side, at a stage when the amplitude reaches a sufficiently large value of the armature, the first from the first current Exciting current changing means for changing to a second current smaller than the first current;
An electromagnetically driven valve for an internal combustion engine, comprising: 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. An electromagnet to be generated, and an electromagnetically driven valve of an internal combustion engine comprising:
When pulling the armature held at the neutral position toward the electromagnet, start control means for executing start control for generating an electromagnetic force at a predetermined cycle on the electromagnet,
In the process of the starting control, the predetermined cycle, a cycle changing means for approaching the natural oscillation cycle from a cycle larger than the natural oscillation cycle of the armature,
In the course of the starting control, the excitation current supplied to the electromagnet when displacing the armature to the electromagnet side, at a stage when the amplitude reaches a sufficiently large value of the armature, the first from the first current Exciting current changing means for changing to a second current smaller than the first current;
An electromagnetically driven valve for an internal combustion engine, comprising:

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