JP2000248968A - Solenoid drive valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly drive a valve element, even if the oil pressure supplied to a zero-rush adjuster is insufficient by changing the current-carrying quantity to an electromagnet, compared with in general time, for a prescribed period after the start of the oil pressure supply to the adjuster in a solenoid drive valve, concerning the intake and exhaust valves of an internal combustion engine. SOLUTION: When the current-carrying to an upper coil 58 is stopped in the closed state of a valve element 12, an armature shaft 42 is displaced down with the valve element 12 by an upper spring 48 to open the valve element 12. When a current is carried to a lower coil 62 at the time when the displacement of the armature shaft 42 reaches a prescribed value, a magnetic force acts on an armature 56 to open the valve element 12 to the maximum. At this time, the relative displacement of the valve element 12 and the armature shaft 42 is absorbed by a zero-rush adjuster 40. The current-carrying quantity to the coil is changed according to the relative position of the armature 56 for a prescribed time after the start of oil pressure supply to the adjustor 40 to ensure the reliability of the actuation of the adjustor 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically driven valve, and more particularly to an electromagnetically driven valve having a hydraulic zero lash adjuster interposed between a valve body and an armature.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 10-2524
An electromagnetically driven valve disclosed in Japanese Patent Publication No. 26 is known. The electromagnetically driven valve includes a valve body that functions as an intake valve or an exhaust valve of an internal combustion engine, an armature that works in conjunction with the valve body, and a valve opening that applies electromagnetic force to the armature in the valve opening direction and the valve closing direction, respectively. And a valve closing electromagnet. Therefore, according to the above-mentioned conventional electromagnetically driven valve, the valve element can be reciprocated between the fully closed position and the fully open position by alternately exciting each electromagnet.

Further, in the above-mentioned conventional electromagnetically driven valve, a gap is formed between the armature and the valve body in a state where the armature is attracted by the valve closing electromagnet and the valve body is seated on the valve seat. Is configured. According to this configuration, even when the relative displacement between the valve body and the armature occurs due to thermal expansion of the valve body or wear of the seating surface between the valve body and the valve seat, the relative displacement is absorbed by the gap. Can be.

[0004]

However, if a gap is formed between the valve body and the armature as in the above-mentioned conventional electromagnetically driven valve, the armature collides with the valve body when the valve body is opened. As a result, a collision noise is generated, and the operation noise of the electromagnetically driven valve increases. In order to prevent such an increase in operating noise,
It is conceivable to provide a hydraulic zero lash adjuster between the valve body and the armature. The zero lash adjuster is a mechanism that expands and contracts according to the relative displacement between the valve body and the armature. By providing such a zero lash adjuster, it is possible to prevent a gap from being formed between the valve element and the armature while absorbing the relative displacement between the valve element and the armature, thereby reducing operation noise.

[0005] As a hydraulic zero lash adjuster, there is an external hydraulic supply type zero lash adjuster which operates by being supplied with hydraulic pressure from the outside. Such an external hydraulic supply type zero lash adjuster is extended by following a change in the distance between the valve element and the armature by supplying hydraulic pressure when the valve element reaches a predetermined position (for example, a valve closing position). Accordingly, it is possible to prevent a gap from being formed between the valve element and the armature while absorbing a change in the relative position.

In such an external hydraulic supply type zero lash adjuster, if the supply hydraulic pressure is insufficient, the zero lash adjuster does not extend sufficiently, and the armature is displaced toward the valve body more than usual. in this case,
The distance between the armature and the electromagnet changes, and the electromagnetic force applied to the armature changes according to the change in the distance. For this reason, if sufficient current is not supplied to the external hydraulic supply type zero-lasher adjuster and the electromagnet is energized using the same current as normal, the valve may not be able to be driven properly. There is.

The present invention has been made in view of the above points, and in an electromagnetically driven valve having an externally supplied hydraulic zero lash adjuster, the position of the armature changes due to insufficient hydraulic pressure supplied to the hydraulic zero lash adjuster. It is another object of the present invention to appropriately drive the valve body in the case where it is performed.

[0008]

The above object is achieved by the present invention.
As described in the above, an armature interlocked with the valve body, an electromagnet that applies an electromagnetic force to the armature, interposed between the valve body and the armature, the hydraulic pressure is supplied by the In the electromagnetically driven valve including a zero lash adjuster that extends following a change in the distance between the valve element and the armature, and an energizing unit that energizes the electromagnet, after hydraulic pressure supply to the zero lash adjuster is started The predetermined period is attained by an electromagnetically driven valve provided with an energization amount changing means for changing an energization amount to the electromagnet by the energization means with respect to a normal time.

According to the first aspect of the present invention, the zero lash adjuster extends in response to a change in the distance between the valve body and the armature when hydraulic pressure is supplied. For this reason, immediately after the hydraulic pressure supply to the zero lash adjuster is started,
The zero lash adjuster is not sufficiently extended, and the position of the armature changes to the valve body side in a normal state (that is, the state where the zero lash adjuster is extended until the gap between the valve body and the armature is eliminated). . On the other hand, the amount of energization to the electromagnet required to apply the required electromagnetic force to the valve body changes according to the relative position between the armature and the electromagnet. Therefore, according to the present invention, after the supply of the hydraulic pressure to the zero lash adjuster is started, for a predetermined period of time, the energization amount changing means changes the energization amount to the electromagnet with respect to the normal time, so that an appropriate electromagnetic force for the armature is obtained. Power is applied.

In this case, the electromagnetically driven valve according to claim 1 includes a relative position related value detecting means for detecting a relative position related value corresponding to a relative position between the armature and the electromagnet. In addition to the above, the energization amount changing means may set the energization amount to the electromagnet according to the relative position related value.

According to the second aspect of the present invention, since the amount of current to the electromagnet is set according to the relative position-related value corresponding to the relative position between the armature and the electromagnet, a more appropriate electromagnetic force is applied to the armature. Granted. According to a third aspect of the present invention, in the electromagnetically driven valve according to the second aspect, the relative position-related value is an elapsed time from when hydraulic pressure supply to the zero lash adjuster is stopped to when it is restarted. It may be that.

In a state where the hydraulic pressure is not supplied to the zero lash adjuster, the oil gradually leaks from the zero lash adjuster, and the zero lash adjuster gradually contracts as time passes. With the contraction of the zero lash adjuster, the relative position between the armature and the electromagnet changes. Therefore, as described in claim 3, the elapsed time from when the hydraulic pressure supply to the zero lash adjuster is stopped to when it is restarted can be used as the relative position-related value.

Further, as described in claim 4, claim 2
In the electromagnetically driven valve described above, the relative position-related value may be a hydraulic pressure value supplied to the zero lash adjuster. As described above, the zero lash adjuster extends when hydraulic pressure is supplied. This extension amount changes according to the hydraulic pressure supplied to the zero lash adjuster. Therefore, as described in claim 4, the hydraulic pressure value supplied to the zero-lash adjuster can be used as the relative position-related value.

[0014]

FIG. 1 shows the configuration of an electromagnetically driven valve 10 according to an embodiment of the present invention. Electromagnetic drive valve 10 of the present embodiment
Are provided corresponding to each exhaust valve and each intake valve of the internal combustion engine. The electromagnetically driven valve 10 is connected to an electronic control unit (hereinafter referred to as E
CU) 11. As shown in FIG.
The electromagnetically driven valve 10 includes a valve body 12 that functions as an intake valve or an exhaust valve. The valve body 12 is provided in the combustion chamber 1 of the internal combustion engine.
The lower head 16 is disposed so as to be exposed inside the lower head 4. A port 18 is formed in the lower head 16.
A valve seat 20 for the valve element 12 is formed at an opening of the port 18 to the combustion chamber 14. Port 18 is connected to valve 1
2 is brought into a conductive state by being separated from the valve seat 20,
In addition, the valve body 12 is shut off by sitting on the valve seat 20.

A cylinder head spacer 24 is disposed above the lower head 16 via a heat insulating plate 22. The heat insulating plate 22 is a sheet-like member made of a heat insulating material such as bakelite, for example.
4 has a function of suppressing transmission of high heat generated from the lower head 16 to the cylinder head spacer 24. Above the cylinder head spacer 24, an upper head 25 is fixed.

The valve body 12 has a valve shaft 26 extending upward. The valve shaft 26 is held by a valve guide 28 so as to be slidable in the axial direction. The valve guide 28 is held by the lower head 16. As will be described later, the valve guide 28 is provided with a sensor (not shown in FIG. 1) for detecting the position of the valve shaft 26. Lower head 16
A spring holding space 30 formed in a cylindrical shape is provided in a portion surrounding substantially the upper half of the valve shaft 26. The upper end of the valve guide 28 is exposed inside the spring holding space 30. Around the upper end portion of the valve guide 28 in the spring holding space 30, a valve stem seal 3 is provided.
1 is attached.

A cotter 32 is mounted near the upper end of the valve shaft 26. The cotter 32 is a substantially cylindrical member having a wedge-shaped outer peripheral surface whose diameter becomes larger toward the upper side in FIG. 1 and an inward projection provided on the inner peripheral surface. The protrusion on the inner peripheral surface of the cotter 32 is fitted into a concave portion provided on the outer peripheral surface of the valve shaft 26. A lower retainer 34 is provided on the outer periphery of the cotter 32.
Is fitted.

A spring seat 36 is provided on the bottom surface of the spring holding space 30. Spring seat 3
Between the lower retainer 6 and the lower retainer 34, a lower spring 38 that generates an urging force in a direction for separating the lower retainer 34 and the lower retainer 34 is disposed. The lower spring 38 urges the valve body 12 upward through the lower retainer 34, that is, in a direction toward the valve seat 20. Hereinafter, the direction in which the valve element 12 moves toward the valve seat 20 is referred to as a valve closing direction, and the direction in which the valve element 12 moves away from the valve seat 20 is referred to as a valve opening direction.

An armature shaft 42 is provided above the valve shaft 26 with a zero lash adjuster 40 therebetween.
And are arranged coaxially. Zero lash adjuster 40
Will be described later in detail. At the upper end of the armature shaft 42, a cotter 44 having a vertically symmetric configuration with respect to the cotter 31 is mounted. An applicator 46 is fitted around the cotter 44. The lower end of an upper spring 48 is in contact with the upper surface of the upper retainer 46. A cylindrical upper case 50 is provided around the upper spring 48. An adjuster bolt 52 is screwed onto the upper part of the upper case 50. The upper end of the upper spring 48 is in contact with the adjuster bolt 52 via a spring guide 54. The upper spring 48 urges the armature shaft 42 downward through the upper retainer 46.

An armature 56 is joined to an outer periphery of a central portion of the armature shaft 42 in the axial direction. The armature 56 is a disk-shaped member made of a soft magnetic material. Above the armature 56, an upper coil 58 and an upper core 60 are provided. Also, armature 56
The lower coil 62 and the lower core 64 are disposed below the lower side. The upper coil 58 and the lower coil 62 are accommodated in annular grooves 60a and 64a formed in the upper core 60 and the lower core 64, respectively.

The upper coil 58 and the lower coil 62 are electrically connected to a drive circuit 65. Drive circuit 65
Supplies a command signal corresponding to a control signal provided from the ECU 11 to the upper coil 58 and the lower coil 62, respectively. The upper core 60 and the lower core 64 are respectively
It has through holes 60b and 64b penetrating the central part. An upper bush 66 is provided at the upper end of the through hole 60b of the upper core 60. Further, a lower bush 68 is disposed at a lower end of the through hole 64b of the lower core 64. The armature shaft 42 is held by an upper bush 66 and a lower bush 68 so as to be slidable in the axial direction. Further, the upper end of the upper core 60 and the lower core 6
4 have flange portions 60c and 64, respectively.
c is provided.

The cylinder head spacer 24 has a cylindrical lash adjuster holding space 24 penetrating therethrough.
a is formed coaxially with the spring holding space 30. Inside the lash adjuster holding space 24a,
The above-mentioned zero lash adjuster 40 is held. An upwardly raised ridge 24b is provided near the opening of the lash adjuster holding space 24a on the upper surface of the cylinder head spacer 24.
A cylindrical portion 24c is formed at the top of b.

In the upper head 25, a cylindrical core holding space 25a penetrating the upper and lower sides thereof is formed coaxially with the spring holding space 30 and the lash adjuster holding space 24a. The upper core 60 has its flange 6
0c is in contact with the upper head 25 via the shim 70, and the lower core 64 is in the core holding space 25a such that the flange portion 64c is in contact with the upper head 25.
Has been inserted. Flange 60c of upper core 60
Is sandwiched between the upper head 25 and a flange 50 a formed at the lower end of the upper case 50.
Further, the flange portion 64c of the lower core 64 is sandwiched between the upper head 25 and the lower bracket 72.
By fixing the upper case 50 and the lower bracket 72 to the upper head 25 with fixing bolts 74 and 76, the upper core 60 and the lower core 64 are fixed at a predetermined interval. In the state where the upper core 60 and the lower core 64 are fixed as described above, a predetermined gap is formed between the raised portion 24b of the cylinder head spacer 24 and the lower surface of the lower core 64. The adjuster bolt 52 described above is adjusted so that the neutral position of the armature 56 is located at an intermediate point between the upper core 60 and the lower core 64.

The cylinder head spacer 24 is provided with oil supply paths 80 and 82 communicating with each other. The oil supply path 80 is supplied with oil from a hydraulic pump 83. The hydraulic pump 83 operates using, for example, rotation of an output shaft of an internal combustion engine as a power source. The oil supply passage 82 opens at a predetermined position on the inner wall surface of the lash adjuster holding space 24a.

The cylinder head spacer 24 further includes
An oil recovery hole 84 is provided. The oil recovery hole 84 vertically penetrates the cylinder head spacer 24 so that the upper end is opened near the raised portion 24 b of the cylinder head 24 and the lower end is opened into the spring holding space 30. In addition, the upper part of the oil recovery hole 84 is provided with the processing holes 84a, 84a.
b, the cylinder head spacer 2
4 A large opening area to the upper surface is ensured. The oil recovery hole 84 has a role of collecting the oil leaking upward from the zero lash adjuster 40 and flowing the oil into the spring holding space 30 to provide the oil as lubricating oil for the armature shaft 42 and the valve shaft 26.

Next, the operation of the electromagnetically driven valve 10 will be described. When a current is supplied to the upper coil 58, an electromagnetic force in a direction toward the upper core 60 acts on the armature 56 by the magnetic flux generated by the upper coil 58. Therefore, as shown in FIG. 1, the armature 56 is displaced until it comes into contact with the upper core 60 against the urging force of the upper spring 48. Hereinafter, a position where the armature 56 contacts the upper core 60 is referred to as a fully closed position of the armature 56, the armature shaft 42, or the valve body 12. In this state, the valve body 12 is seated on the valve seat 20, and the valve body 12 is closed.

With the valve body 12 closed as described above,
When the supply of the current to the upper coil 58 is stopped, the electromagnetic force necessary to hold the armature 56 at the fully closed position disappears. Therefore, when the supply of the current to the upper coil 58 is stopped, the armature shaft 42 starts being displaced downward together with the valve body 12 by being urged by the upper spring 48. For this reason, the valve element 12 is
When the user departs from zero, the valve body 12 is opened. When a current is supplied to the lower coil 62 when the amount of displacement of the armature shaft 42 reaches a predetermined value, an electromagnetic force for urging the armature 56 toward the lower core 64 is generated.

When the electromagnetic force acts on the armature 56, the armature 56 is displaced against the urging force generated by the lower spring 38 until it comes into contact with the lower core 64, and the amount of displacement of the valve body 12 in the valve opening direction is Will be the largest. Hereinafter, the position where the armature 56 contacts the lower core 64 is referred to as the armature 56, the armature shaft 42, or the fully opened position of the valve body 12.

In this state, when the supply of the current to the lower coil 62 is stopped, the electromagnetic force required to hold the armature 56 at the fully open position disappears. Therefore, the valve element 12
The armature shaft 42 starts to be displaced upward by the urging force generated by the lower spring 38. When a current is supplied to the upper coil 58 at the time when these displacement amounts reach a predetermined value, the armature 56 is moved toward the upper core 60 by the electromagnetic force generated by the upper coil 58, and
It is displaced until it touches 0. In a state where the armature 56 is in contact with the upper core 60, the valve body 12 is seated on the valve seat 20, and the valve body 12 is again closed.

As described above, according to this embodiment, the valve body 12 is repeatedly switched between the fully closed position and the fully open position by supplying current to the upper coil 58 and the lower coil 62 alternately at appropriate timing. Can be reciprocated. In the present embodiment, the zero lash adjuster 40 is provided between the valve body 12 and the armature shaft 42 due to a difference in thermal expansion between the valve body 12 and the lower head 16 and wear of the seating surface between the valve body 12 and the valve seat 20. It has a function of preventing the formation of a gap between both members by absorbing the relative displacement. Below, zero lash adjuster 40
Will be described.

FIG. 2 is an enlarged sectional view showing the zero lash adjuster 40 and its peripheral portion. In addition, FIG.
The state realized under the situation where the armature 56 and the valve element 12 are in the fully closed position is shown. As shown in FIG. 2, the zero lash adjuster 40 includes a plunger body 100. The plunger body 100 is slidably disposed in the lash adjuster holding space 24a in the axial direction.
The plunger body 100 has one end (the lower end in FIG. 2).
Is a closed substantially cylindrical member. Plunger body 10
0 has a spring holding portion 100a provided at the lower end thereof, and a plunger holding portion 100b having a larger diameter than the spring holding portion 100a.

A plunger 102 is slidably disposed in the plunger holding portion 100b of the plunger body 100 in the axial direction. A hydraulic chamber 104 is defined between the lower bottom surface of the plunger 102 in FIG. 2 and the lower bottom surface of the spring holding portion 100a. Plunger 102
Has a large-diameter portion 102a that slides on the outer peripheral surface of the plunger holding portion 100b and a small-diameter portion 102b provided at the upper end in FIG. on the other hand,
A stopper ring 106 is press-fitted into the upper end of the inner peripheral surface of the plunger accommodating portion 100b. Stopper ring 10
6 has an inner diameter smaller than the outer diameter of the large diameter portion 102a of the plunger 102. Therefore, the plunger 102
The upward displacement inside the plunger holding portion 100b is caused by a step between the large diameter portion 102a and the small diameter portion 102b,
It is regulated by contact with the stopper ring 106. The plunger 102 also has a reservoir chamber 108 that opens upward, and the reservoir chamber 108 and the hydraulic chamber 1
The communication passage 110 communicates with the communication passage 04.

The hydraulic chamber 104 is provided with a retainer 112 and a plunger spring 114. The plunger spring 114 urges the plunger 102 upward via the retainer 112. A check ball 116 and a check ball spring 118 are provided inside the retainer 112. The check ball spring 118 urges the check ball 116 toward the opening of the communication passage 110. The check ball 116 and the check ball spring 118 function as a check valve that opens only when the pressure in the hydraulic chamber 104 becomes lower than that in the reservoir chamber 108.

The zero lash adjuster 40 also has a reservoir cap 120. The reservoir cap 120 is a cylindrical member having one end (the lower end in FIG. 1) closed. The reservoir cap 120 is slidably disposed in the lash adjuster holding space 24a so that the bottom surface of the reservoir cap 120 contacts the upper end surface of the plunger 102.
On the lower bottom surface of the reservoir cap 120, an overflow recess 122, which is partially cut away, is provided. The overflow recess 122 is provided in the reservoir chamber 108.
He is always in communication with

The lower end surface of the plunger shaft 42 is in contact with the inner bottom surface of the reservoir cap 120. on the other hand,
The upper end surface of the valve shaft 26 is in contact with the outer bottom surface of the plunger body 100. In addition, the oil supply passage 82 has an inner peripheral surface of the lash adjuster holding space 24a so as to communicate with the overflow recess 122 in a state shown in FIG. 2 (that is, a state in which the armature 56 and the valve body 12 are in the fully closed position). It is open to.

When the power supply to the upper coil 58 is cut off from the state shown in FIG. 2, an urging force in the valve opening direction acts on the armature shaft 42 as described above. The force in the valve opening direction is transmitted from the reservoir cap 120 to the plunger 102. When the force transmitted to the plunger 102 exceeds the urging force of the plunger spring 114, the plunger 102 is pressed downward, so that the oil in the hydraulic chamber 104 is pressurized. Therefore, the hydraulic pressure in the hydraulic chamber 104 becomes higher than the hydraulic pressure in the reservoir chamber 108, and the communication passage 110
Is closed by the check ball 116. Communication passage 11
When 0 is closed, transfer of oil between the hydraulic chamber 104 and the reservoir chamber 108 is prohibited. For this reason, plunger 1
02 is transmitted to the plunger body 100 via the hydraulic chamber 104, and the zero lash adjuster 40 becomes substantially rigid, and the plunger shaft 42
And it displaces with the valve body 12 in the valve opening direction. When the zero lash adjuster 40 is displaced in the valve opening direction, the oil in the hydraulic chamber 104 is pressurized, and the hydraulic chamber 104 is moved through the sliding surface between the plunger 102 and the plunger body 100.
, The lash adjuster 40 contracts by a small amount corresponding to the oil leakage.

When the armature 56 is displaced until it comes into contact with the lower core 64 and the power supply to the lower coil 62 is stopped,
The armature 56 is displaced in the valve closing direction. And valve element 1
When the seat 2 is seated on the valve seat 20, the urging force of the lower spring 38 does not act on the plunger body 100. On the other hand, even after the valve body 12 is seated on the valve seat 20, the armature 56 is further displaced in the valve closing direction by a minute amount corresponding to the contraction of the lash adjuster 40 in the process of displacing the valve body 12 in the valve opening direction. I do. In this case, the plunger 102 attempts to slide upward with respect to the plunger body 100 following the reservoir cap 120 by the urging force of the plunger spring 114, and the hydraulic chamber 1
The oil pressure in 04 drops. When the pressure in the hydraulic chamber 104 becomes lower than that in the reservoir chamber 108, the check ball 11
The hydraulic chamber 104 and the reservoir chamber 108 communicate with each other when the valve 6 is separated from the opening of the communication passage 110. As mentioned above,
When the valve element 12 is seated on the valve seat 20, the oil supply path 82 and the overflow recess 122 communicate with each other.
Therefore, when the hydraulic chamber 104 and the reservoir chamber 108 communicate with each other, the oil pressure-fed from the hydraulic pump 83 to the oil supply path 80 flows from the oil supply path 82 through the reservoir chamber 108 to the hydraulic chamber 1.
When supplied to the reservoir cap 120, the plunger 102 slides upward while maintaining the state of being in contact with the reservoir cap 120.

As described above, the zero lash adjuster 40
In the state where the valve element 12 is opened and the axial compressive force acts as a reaction force against the urging force of the lower spring 38,
It becomes substantially rigid and displaces with the armature shaft 42 and the valve body 12 while the valve body 12 is
In a state where no compression force acts on the zero lash adjuster 40, the plunger 102 is allowed to slide with respect to the plunger body 100. Due to the function of the zero lash adjuster 40, the thermal expansion difference between the valve body 12 and the lower head 16 and the valve body 12 and the valve seat 20
Due to wear of the seating surface with the reservoir cap 120
When the relative position changes between the plunger 102 and the plunger body 100,
By sliding with respect to 0, the state where the armature shaft 42 and the reservoir cap 120 are in contact with each other is maintained. Therefore, according to the electromagnetically driven valve 10 of the present embodiment, the valve body 12 is reliably opened and closed between the fully closed position and the fully open position without generating a gap between the armature shaft 42 and the valve body 12. be able to.

When the ignition switch of the vehicle on which the internal combustion engine is mounted is off, the electromagnetically driven valve 1
Neither the zero upper coil 58 nor the lower coil 62 is energized. Therefore, when the ignition switch is turned on, the valve body 12 is held at the neutral position between the fully closed position and the fully opened position by the upper spring 48 and the lower spring 38. In this neutral position, the armature 56 is separated from the upper coil 58 and the lower coil 62, and the biasing forces of the upper spring 48 and the lower spring 38 acting on the plungers are balanced. For this reason, when the valve element 12 is in the neutral position, the urging force of any spring cannot be used,
The valve element separated from the upper coil 58 and the lower coil 62 must be sucked, and it is difficult to drive the valve element 12 at a required timing. Therefore, in order to ensure a smooth start of the internal combustion engine, it is necessary to displace the valve body 12 to the fully closed position or the fully open position after the ignition switch is turned on, and to hold the valve body 12 at that position.

FIGS. 3A and 3B respectively show the state after the ignition switch is turned on in the present embodiment.
By the time the opening and closing operation of the valve body 12 is started, the upper coil 5
8 shows the waveforms of the command current supplied to the lower coil 8 and the lower coil 62, respectively. FIG. 3C shows a lift waveform of the valve element 12 when the above-described command current is supplied to each coil.

As shown in FIG. 3, the driving of the electromagnetically driven valve 10 is performed in three sections: a starting section, a holding section, and a working section. First, in the starting section, as shown in FIGS. 3A and 3B, a command current having a pulse that changes between “0” and a predetermined value I _U at a predetermined cycle T is supplied to the upper coil 58. is, in the lower coil 62 is in a state of phase with the current supplied to the upper coil 58 is delayed 180 degrees, the command current having a pulse that changes between "0" and the predetermined value I _L with a predetermined period T Is supplied. The above-described period T is a spring-mass determined by the mass of the movable portion of the electromagnetically driven valve 10 (ie, the armature 56 and the portion that moves integrally with the armature 56) and the spring constants of the upper spring 48 and the lower spring 38. It is set to a value equal to the natural oscillation period of the system.

Therefore, in the starting section, the armature 56
Then, the electromagnetic force toward the valve opening side and the electromagnetic force toward the valve closing side act alternately with a period T equal to the natural vibration period, thereby exciting the natural vibration of the movable part. As a result, as shown in FIG. 3C, in the starting section, the vibration amplitude of the valve element 12 gradually increases, and finally, the valve element 12
Reaches the fully closed position (that is, the armature 56 comes into contact with the upper core 64). In the holding section, the command current for the lower coil 62 is set to “0” and the command current for the upper coil 58 is set to a predetermined holding current I _H , so that the armature 56 and the valve element 12 are held at the fully closed position. You. Hereinafter, the process for displacing the valve body 12 to the fully closed position using the natural vibration of the movable portion in the above-described starting section is referred to as “initial drive”.

Thereafter, in the actual operation section, the upper coil
When the command current to 58 is set to "0", the valve
12 starts displacement in the valve opening direction. And a suitable tie
At the same time, the attraction current I_A, Trans
Transfer current I_TAnd the holding current I _HCommand of pattern consisting of
Current is supplied. According to the current of such a pattern,
Current I_AThe armature 56 near the lower core 64
Until the transition current I_TArmature by
56 is sucked while contacting the lower core 64 while being decelerated.
And finally the holding current I_HArmature 56
The suction is held by the accor 64. Thereafter, the upper coil 58
And the lower coil 62 alternately outputs the command current of the above pattern.
By being supplied, the opening and closing operation of the valve element 12 is performed.
It will be.

By the way, as described above, the zero lash adjuster 40 is operated when the valve body 12 reaches the vicinity of the fully closed position.
When the oil is supplied from the oil supply passages 80 and 82, the plunger body 100 slides with respect to the plunger 102, and when the armature 56 and the valve body 12 reach the fully closed position, the valve body 12, the armature shaft 42 To prevent a gap from occurring between them. Note that a gap generated between the valve body 12 and the armature shaft 42 when the armature 56 and the valve body 12 reach the fully closed position is hereinafter referred to as tappet clearance. In addition, a state in which the tappet clearance becomes zero due to the zero-lasher adjuster 40 exhibiting the above function is hereinafter referred to as a zero-rush state. Further, in the zero rush state, the energization of the upper coil 58 and the lower coil 62 is stopped, and the movable portion is
Hereinafter, the position of the armature 56 held by the lower arm 8 and the lower spring 38 is referred to as a neutral reference position of the armature 56.

However, when the ignition switch of the internal combustion engine is turned off, neither the upper coil 58 nor the lower coil 62 is energized. Therefore, the armature 56 is held near the neutral position, and the hydraulic pressure supply to the zero lash adjuster 40 is not performed. Not done. On the other hand, when the armature 56 is held near the neutral position, a compressive force acts on the zero lash adjuster 40 by the upper spring 48 and the lower spring 38. For this reason,
When oil leaks from the hydraulic chamber 104 via the sliding surface between the plunger body 102 and the plunger 100, the zero lash adjuster 40 gradually contracts in the axial direction. The phenomenon in which the zero lash adjuster 40 contracts due to the leakage of oil from the hydraulic chamber 104 is hereinafter referred to as the leak-down of the zero lash adjuster 40. When the leak-down occurs, the position of the armature 56 changes from the neutral reference position to the lower core 64 side accordingly. Therefore, the distance between the armature 56 and the upper core 60 and the lower core 64 at the time when the ignition switch is turned on changes according to the leak-down amount of the zero lash adjuster 40.

FIG. 4 shows the relationship between the position of the armature 56 and the electromagnetic force acting on the armature 56 from the lower core 64.
The case where the level is changed will be described. As shown in FIG.
When a constant current is supplied to the lower coil 62, the electromagnetic force acting between the armature 56 and the lower core 64 becomes smaller as the armature 56 is displaced toward the upper core 60. When the position of the armature 56 is constant, the electromagnetic force acting on the armature 56 increases as the current supplied to the lower coil 62 increases. Due to such characteristics, the current to be supplied to the lower coil 62 in order to apply a required electromagnetic force in the valve opening direction to the armature 56 becomes smaller as the armature 56 is displaced toward the lower core 58 side. Similarly, the current to be supplied to the upper coil 58 to apply the required electromagnetic force in the valve closing direction to the armature 56 increases as the armature 56 is displaced toward the lower core 64.

Therefore, in the initial drive, the command currents I _U and I _U for the upper coil 58 and the lower coil 62 are
_{If a} constant value is used as _L regardless of the position of the armature 56, the electromagnetic force when driving the armature 56 to the upper core 60 is insufficient because the armature 56 is displaced toward the lower core 64 when the ignition is turned on. As a result, the initial drive may not be performed properly. In this case, more current than necessary is supplied to the lower coil 62, so that power consumption is unnecessarily increased. Electromagnetically driven valve 10 of the present embodiment, in view of the above, thereby changing the command current I _U and I _L in the initial driving in accordance with the position of the armature 56.

FIG. 5 shows an initial state according to the position of the armature 56.
To lower coil 62 and upper coil 58 in initial drive
Command current I_LAnd I_UMap referenced to determine
This is an example. As shown in FIG.
The command current I increases as the displacement to the Pacoa 60 side occurs._LIncrease
As a result, the rotor acting on the armature 56 in the initial drive is
Securing the required electromagnetic force to the Accor 64
Can be. Also, the armature 56 moves to the upper core 60 side.
The command current I to the upper coil 58 increases as the displacement increases. _UThe small
By doing so, an unnecessarily large voltage is applied to the upper coil 58.
Current can be prevented, thereby saving power.
Can be planned.

FIG. 6 shows the armature 5 in this embodiment.
6 is a perspective view showing a configuration for performing position detection of FIG. As described above, the displacement of the armature 56 toward the lower core 64 is caused by the contraction of the zero lash adjuster 40 due to the leak down. When a leak-down occurs in the zero lash adjuster 40, the armature shaft 42 is displaced downward across the zero lash adjuster 40, and the valve body 12 is displaced by an amount substantially equal to the displacement.
Is displaced upward. Therefore, in this embodiment, the valve shaft 26
, The position of the armature 56 is indirectly detected.

As shown in FIG. 6, the valve guide 28 is provided with a notch 28a. A pair of gap sensors 150 and 152 provided so as to sandwich the valve shaft 26 from both sides in the radial direction are mounted on the notch portion 28a via sensor holders 154 and 156, respectively. A terminal film 158 for taking out an output signal to the outside is mounted.
FIG. 6 shows the gap sensors 150 and 152, the sensor holders 154 and 156, and the terminal film 158.
Indicate a state separated from each other. The gap sensors 150 and 152 are, for example, eddy current type gap sensors, and transmit an electric signal corresponding to the magnitude of the gap between the gap sensor and the outer peripheral surface of the valve shaft 26 via the terminal film 158 to the ECU.
Output to 11 However, the gap sensors 150, 15
Another type of gap sensor such as an electrostatic type may be used as 2 FIG. 7 is a cross-sectional view when the valve guide 28 and the valve shaft 26 are cut in the axial direction. As shown in FIG. 7, the valve shaft 26 is provided with a concave portion 160 having a rectangular cross-sectional shape over the entire circumference. When the valve body 12 is in the fully closed position, the center of the gap sensors 150 and 152 faces the step 160a below the recess 160, and the valve body 12 is neutral. When in the position, the gap sensors 150 and 152 are arranged such that the central portions thereof face the step portion 160 b above the concave portion 160. Therefore, the axial length of the recess 160 is
This means that the lift amount is set to approximately half of the lift amount when the valve body 12 is displaced from the fully closed position to the fully opened position.

The output voltage V of the gap sensors 150 and 152 is such that the entire surface of the gap sensors 150 and 152
Sites other than the recess 160 of the (hereinafter referred to as the general part of the valve shaft 28) when the outer peripheral surface and opposed, the minimum voltage V _max, and the entire surface of the concave portion 160 of the gap sensors 150, 152
In this case, the maximum voltage Vmax is _reached . Note that the output voltage V of the gap sensors 150 and 152 means an average value of the output voltages of both sensors.

FIG. 8 shows changes in the positional relationship between the gap sensors 150 and 152 and the recess 160 when the valve element 12 is displaced from the fully closed position to the fully open position. FIG. 9 shows the output voltages V of the gap sensors 150 and 152 when the valve body 12 is displaced from the fully closed position to the fully open position.
Shows the change in As shown in FIG. 8A, when the valve body 12 is in the fully closed position, substantially half of the gap sensors 150 and 152 face the general portion of the valve shaft 28, and the other half is the concave portion 1
It faces 60. In this state, the gap sensor 15
The output voltage V of 0,152 is an intermediate value V _s of the maximum voltage V _max and a minimum voltage _{V max (≒ (V max +} V max) / 2).

When the valve body 12 starts displacing from the fully closed position in the valve opening direction, the concave portions 16 of the gap sensors 150 and 152
The output voltage V gradually increases due to the increase in the area of the portion facing 0 (period I in FIG. 9). And in FIG.
As shown in (2), in a state where the valve body 12 is displaced until the entire gap sensor 150, 152 is opposed to the recess 160, the output voltage V is (the period II in FIG. 9) which is maintained at the maximum voltage V _max.

When the valve body 12 reaches the vicinity of the neutral position, FIG.
As shown in FIG. 7, the gap sensors 150 and 152 are opposed to the step 156b on the upper side of the concave portion 160. Therefore, as the valve element 12 is displaced, the output voltage V gradually decreases (period III in FIG. 9). Then, the valve body 12 is further displaced toward the fully closed position, and the gap sensor 150,
When the entire portion 152 faces the general portion of the valve shaft 28, the output voltage V is maintained until the valve body 12 reaches the fully open position.
_Are kept at the minimum voltage Vmax (period IV in FIG. 9).

As described above, when the valve element 12 is in the vicinity of the neutral position (period III in FIG. 9), the output voltage V changes according to the displacement of the valve shaft 28. For this reason, the position of the valve shaft 28 at that time can be detected based on the output voltage V at the time when the ignition switch is turned on. That is, when the valve element 12 is displaced upward due to the leak-down of the zero-rush adjuster 40, the output voltage V is higher than a value in a state where no leak-down occurs (a zero-rush state) (hereinafter, referred to as a reference voltage V0). Will increase. Therefore, the ECU 11 changes the output voltage V at the time when the ignition switch is turned on to the reference voltage V0.
By comparing with, the position of the valve shaft 28 is detected, and based on this, the displacement amount from the neutral reference position of the armature 56 to the lower core 64 can be detected.

The output voltages V of the gap sensors 150 and 152 in a state where the valve body 12 is held at the fully closed position.
_s changes according to the relative position between the armature 56 and the valve body 12. Therefore, based on the output voltage V _s of at the time the initial driving is completed, it is possible to determine whether the zero lash state is achieved. If it is determined that the zero rush state has not yet been realized at the time when the initial driving is completed, the command current to the upper coil 58 is set to be larger than the normal time for a certain period after the start of the active section. Thereby, the opening and closing drive of the valve body 12 may be reliably performed.

When the thermal expansion occurs in the valve body 12, the position of the concave portion 160 of the valve shaft 28 changes accordingly. Therefore, based on the output voltage V _s at the fully closed position, it is also possible to detect the thermal expansion of the valve body 12. Further, as described above, by using the average value of the output voltages of the gap sensors 150 and 152 as the output voltage V, even when the output voltage of each sensor changes due to the displacement of the valve shaft 28 in the radial direction, the influence is also exerted. And the position of the valve element 12 can be accurately detected.

FIG. 10 shows the command current I _L in the initial drive.
And is a flowchart of a routine that ECU to determine the I _U executes. The routine shown in FIG. 10 is executed only once immediately after the ignition switch is turned on. When the routine shown in FIG. 10 is started, first, the process of step 200 is executed. In step 200, the position of the armature 56 is detected based on the output voltages V of the gap sensors 150 and 152 by the above-described method.

[0059] At step 202, based on the detected position of the armature 56, by referring to the map shown in FIG. 5, the command current I _L and I in the initial driving
_U is determined. In step 204, step 202
A process for starting the initial drive using the command currents I _L and I _U determined in the above is performed. When the process of step 204 ends, the current routine ends.

As described above, in the present embodiment, the command currents I _L to the lower coil 62 and the upper coil 58 in the initial drive according to the position of the armature 56 before the start of the initial drive,
I _U is determined. Therefore, the electromagnetically driven valve 10 of this embodiment
According to this, even when the position of the armature 56 changes due to the leak-down of the zero lash adjuster 40, the initial driving can be appropriately performed, and the power consumption in the initial driving can be suppressed.

In the above embodiment, based on the fact that the valve shaft 28 and the armature 56 are displaced by substantially the same distance as the zero lash adjuster 40 leaks down,
The position of the armature 56 is indirectly detected by detecting the position of the valve shaft 28. However, the position of the armature 56 may be directly detected.

FIG. 11 shows an example of a configuration in which the position of the armature 56 is directly detected by the gap sensor 250. In the configuration shown in FIG.
And an extension 4 that penetrates the adjuster bolt 52 upward.
2a is provided, and the measurement target 252 is fixed to the tip of the extension 42a. A gap sensor 250, for example, an eddy current sensor, is fixed above the measurement target 252. The gap sensor 250 outputs a signal corresponding to the distance from the measurement target 252 to the ECU 11. Therefore, according to the configuration shown in FIG. 11, the armature 5 is controlled based on the output signal of the gap sensor 252.
6 can be directly detected.

FIG. 12 shows a configuration in which the position of the armature 56 is directly detected by the laser type distance sensor 260. The laser type distance sensor 260 irradiates a laser beam emitted from a semiconductor laser to a measurement target, and measures the distance to the measurement target by the principle of triangulation by detecting the position of the reflected light. Similar to the configuration shown in FIG. 11, an extension 42 a penetrating upward through the adjuster bolt 52 is provided on the armature shaft 42, and a laser beam from a laser distance sensor 260 is applied to the distal end surface of the extension 42 a. Since the spot diameter of the laser beam is small and only a small surface to be measured is required as compared with the case of the eddy current gap sensor, the measurement target 252 is configured as shown in FIG.
It is not necessary to provide.

Next, a second embodiment of the present invention will be described. In the present embodiment, a predetermined period after the start of the active section is performed in order to appropriately perform the opening / closing drive of the valve element 12 even when the zero rush state is not realized when the initial drive is completed.
The command current to the upper coil 58 and the lower coil 62 is changed from the normal time. FIG. 13 shows the electromagnetically driven valve 10 in a state where the armature 56 is in the fully opened position, (A) when the zero lash adjuster 40 does not leak down, and (B) when the zero lash adjuster 40 leaks down. For each case.

As shown in FIGS. 13A and 13B, when the leak-down occurs, the valve body 12 is displaced toward the armature 56 as compared with the case where the leak-down does not occur. Therefore, when the leak-down occurs, the contraction amount of the lower spring 38 decreases correspondingly. In this case, since the elastic force acting on the valve body 12 in the valve closing direction decreases, the current to be supplied to the upper coil 58 to close the valve body 12 increases. Further, when the leak down occurs, when the valve body 12 is driven from the fully closed position in the valve opening direction,
Armature 56 is valve body 1 for tappet clearance
The distance to drive 2 becomes shorter. Therefore, in order to drive the valve element 12 from the fully closed position to the fully open position, the lower coil 6 is driven.
The current to be supplied to 2 becomes smaller.

As described above, the zero lash adjuster 40
When the leak-down occurs, the current to be supplied to the upper coil 58 increases and the current to be supplied to the lower coil 62 decreases as compared with the case where the leak-down does not occur. Therefore, in the present embodiment, the command current to the lower coil 62 is made larger than the command current to the upper coil 58 for a predetermined period after the completion of the initial drive, so that the valve body 12 is set to the fully closed position while suppressing power consumption. Operate reliably between the fully open position.

FIGS. 14A and 14B show the waveforms of the command current supplied to the upper coil 58 and the lower coil 62 in this embodiment, respectively. In FIG. 14, a broken line indicates a command current that is normally used (that is, when the zero rush state is realized). FIG.
As shown, after initiation of the production period for a predetermined N cycles, attracting current I _A and the holding current I _H to the lower coil 62, respectively, the reference value (i.e., the current value at zero lash state) I _A0 and The values are set to values I _A1 and I _H1 smaller than I _H0, and the attraction current I _A and the holding current I _H to the upper coil 58 are respectively set to the reference value I _H0.
Than _A0 and I _H0 is set to a value I _A2 and I _H2.
Note that one cycle means one reciprocation between the fully closed position and the fully opened position of the armature 56 and the valve element 12. The number of cycles N is equal to zero lash adjuster 4
The number of cycles is set so that the hydraulic pressure is sufficiently supplied to 0 and the number of cycles required until the zero rush state is realized. After the end of N cycles, a predetermined N2
Over cycles, the attracting current I _A and the holding current I _H for the upper coil 58 is reduced gradually toward the I _A0 and I _H0, attracting current I _A and the holding current I _H to the lower coil 62 to I _A0 and I _H0 It is gradually increased toward. Note that different values may be used for the upper coil 58 and the lower core 62 as the reference values I _A0 and I _H0 .

FIG. 15 shows an example of an ECU for realizing the above operation.
11 is a flowchart of a routine that is executed. FIG.
The routine shown in FIG. 5 is started when the initial driving is completed. When the routine shown in FIG. 15 is started, first, the process of step 300 is executed. In step 300,
A variable n indicating the number of operation cycles of the valve body 12 is initialized to “1”.

In step 302, it is determined whether or not a request to open the valve body 12 has been issued. Step 302
Is repeatedly performed until a request to open the valve body 12 is issued. If a request to open the valve body 12 has been issued in step 302, the process of step 304 is executed next. In step 304, a process for supplying a lower current to the lower coil 62 than usual, that is,
To the lower coil 62, the attracting current I _A I _A1, processing for supplying the command current to the holding current I _H to the I _H1 is performed.

In step 306, it is determined whether a request to close the valve body 12 has been issued. Step 306
Is repeatedly performed until a request to close the valve body 12 is issued. If a request to close the valve body 12 has been issued in step 306, then the process of step 308 is executed. In step 308, the process for supplying a current larger than normal in the upper coil 58, i.e., the upper coil 58, the attracting current I _A I _A2,
Processing for supplying a command current with the holding current I _{H set} to I _H2 is executed.

In step 310, it is determined whether or not n> N. As a result, if n> N is not satisfied, then the variable n is incremented in step 312, and then the process of step 302 is executed again. On the other hand, when n> N is satisfied in step 310, the process of step 314 is executed next. In step 314, the variable n is initialized to "1" again.

In step 316, it is determined whether a request to open the valve body 12 has been issued. Step 316
Is repeated until a request to open the valve body 12 is issued. If a request to open the valve body 12 has been issued in step 316, then the process of step 318 is executed. In step 318, to the lower coil 62, the process for the attracting current _{I A I A1 + n · ΔI} A1, the holding current I _H to supply a command current was I _H1 + n · ΔI _H1 is performed. Note that ΔI _A1 and ΔI _H1 are respectively
ΔI _A1 = (I _A0 −I _A1 ) / N1, ΔI _H1 = (I _H0 −
I _H1 ) / N 1. Step 3
According to 18 of the processing, attracting current I _A and the holding current I _H is the normal of the respective values I _A0 and I to the lower coil 62
It is gradually increased toward _H0 .

In step 320, it is determined whether or not a valve closing request has been issued. The process of step 320 is repeatedly performed until a request to close the valve body 12 is issued. If a valve closing request for the valve element 12 has been issued in step 320, the process of step 322 is executed next. In step 322, the attracting current I _A I _A2 -n · ΔI _A2 relative to the upper coil 58, the holding current I _H I _H2 -
Processing for supplying a command current with n · ΔI _H2 is executed. Note that ΔI ₂ and ΔI _H2 are ΔI ₂
= (I _A2 −I _A0 ) / N1, ΔI _H2 = (I _H2 −I _H0 ) / N
It is set to be 1. According to the process of step 322, attracting current I _A and the holding current I _H for the upper coil 58 is gradually decreased toward the value I _A0 and I _H0 of normal, respectively.

At step 324, it is determined whether or not n> N1 is satisfied. As a result, if n> N1 is not satisfied, then the variable n is incremented in step 326, and then the process of step 316 is executed again. On the other hand, if n> N1 is satisfied in step 324, thereafter, in step 328, each time a normal opening / closing operation, that is, a valve opening request and a valve closing request are issued, the lower coil 62 and the upper coil 58 are respectively operated. _A process for supplying a command current for setting the attraction current IA to I _A0 and the holding current I _H0 is executed.

[0075] As described above, in this embodiment, after the initial driving completion, by supplying a large attracting current I _A and the holding current I _H than normal in a predetermined N cycles by the upper coil 58, the zero lash adjuster 40 , The armature 56 can be driven until it comes into contact with the upper core 60, whereby the electromagnetically driven valve 10 can be reliably opened and closed. Also,
Vacuum until the armature 56 abuts on the upper core 60 by the attraction current Sarezu, transition current I _T or holding current I _H
When the armature 56 comes into contact with the upper core 60 at a high speed when the suction is performed again by the upper core 60, a large contact sound is generated. On the other hand, in the present embodiment, the armature 56 is connected to the upper core 6 as described above.
Since the suction can be surely performed until the contact is made with zero, it is possible to prevent the generation of the contact sound as described above.

Further, during the above-mentioned N cycle, by supplying a lower attracting current and holding current to the lower coil 62 than usual, it is possible to prevent an excessive electromagnetic force in the valve opening direction from acting on the armature 56. Can be. Therefore, it is possible to prevent the armature 56 from contacting the lower core 64 at a high speed to generate a large contact sound, and to suppress the power consumption on the lower coil 62 side.

In the above embodiment, the case where the command current to each coil is changed after the initial drive performed when the internal combustion engine is started has been described. However, the electromagnetic drive valve 10 loses synchronism (while the opening and closing of the valve body 12 is being driven, the armature 56
(The phenomenon that the armature 56 cannot be driven because the armature 56 cannot be driven because the armature 56 cannot be driven to the upper core 60 or the lower core 64), and the armature 56 and the valve body 12 are fully closed by the same processing as the initial drive. The solenoid-operated valve 10 is driven to the position to recover from the step-out state. Therefore, when the opening / closing drive of the valve body 12 is started after the recovery process from the step-out, the command current to each coil is changed during the predetermined cycle, similarly to the above-described embodiment. It should be fine.

[0078] In the above embodiment, during the N cycles after the start production section it is assumed that changing both attracting current I _A and the holding current I _H, is not limited to this, the holding current I _H
Using the reference value I _H0 for, it may be changed only attracting current I _A. Further, in the above embodiment, during the N cycles, attracting current I _A and the holding current I _H is fixed to the I _A1, I _A2 and I _H1 and I _H2, respectively, the reference value I _A0 in the next N1 cycles, I it is assumed to gradually change toward the _H0, not limited to this, immediately after the start of the production period, attracting current I _a and the holding current I _H to the reference value I _a 0, I
It may be changed gradually toward _H0 .

Next, a third embodiment of the present invention will be described. In the present embodiment, in view of the fact that the leak-down amount of the zero-lash adjuster 40 changes according to the elapsed time after the opening / closing drive of the valve element 12 is stopped, the second embodiment according to the second embodiment according to the elapsed time. Attraction currents I _A1 and I _A2 and holding currents I _H1 and I _H2 are set. As described above, the leak down of the zero lash adjuster 40 may be caused by the oil gradually flowing from the hydraulic chamber 104 in a state where the armature 56 and the valve body 12 are held near the neutral position, that is, in a state where the hydraulic pressure is not supplied to the zero lash adjuster 40. Is a phenomenon that leaks into
Therefore, the longer the time that the armature 56 and the valve element 12 are held near the neutral position (for example, the time that the ignition switch is turned off) is longer, the larger the amount of leak-down of the zero lash adjuster 40 is. Accordingly, in this embodiment, zero-lash adjuster 40 time elapsed after the hydraulic pressure supply is stopped to (hereinafter, referred to as the valve stopping time T _s) in accordance with the suction current I _A1, I against upper coil 58 and lower coil 62 _A2 and holding currents I _H1 and I _H2 are determined.

FIG. 16 exemplifies the relationship between the valve stop time T _s and the amount of displacement of the armature 56 from the neutral position to the lower core 64 side. Note that the relationship shown in FIG. 16 is obtained by determining the position of the armature 56 to the various valve stop time T _s experimentally. FIG. 17 shows a map that is referred to determine the above-described suction currents I _A1 and I _A2 and the holding currents I _H1 and I _H2 from the valve stop time T _s .

[0081] As shown in FIG. 16, the longer the valve stopping time T _s, the displacement amount from the neutral position of the armature 56 toward the lower cores 64 side increases. Correspondingly, as shown in FIG. 17, the longer the valve stopping time T _s, thereby increasing the attraction current I _A2 and the holding current I _H2 for the upper coil 58, suction to the lower coil 62 current I _A1 and the holding current I _H1 Is reduced, the opening and closing drive of the valve element 12 can be appropriately performed.

FIG. 18 is a graph showing the draw currents I _A1 and I _{A2 as} described above.
9 is a flowchart of a routine executed by the ECU 11 to determine the holding currents I _H1 and I _H2 . The routine shown in FIG. 18 is started when the ignition switch is turned on. In this embodiment, the routine shown in FIG. 15 is executed together with the routine shown in FIG. When the routine shown in FIG.
0 is executed.

In step 400, the time during which the ignition switch was turned off, that is, the valve stop time T _s
Is detected. ECU11 includes a counter that time unit is counted up each time elapses, to detect the valve stopping time T _s by resetting to "0" when the ignition switch is turned off. Step 40
At 2, the attraction currents I _A1 and I _A2 and the holding currents I _H1 and I _H2 for each coil are determined from the valve stop time T _s with reference to the map shown in FIG. In step 404, processing for realizing the initial driving is executed. Step 4
When the process of step 04 is completed, this routine is terminated.
With _{I A1, I A2, I H1} , I H2 determined in step 402, the routine shown in FIG. 15 is executed.

[0084] In the above third embodiment, when the initial driving completion of start real dynamic interval, it is assumed that changes the attracting current I _A and the holding current I _H for each coil in accordance with the valve stopping time T _s is not limited to this, the command current I _U and I _L a valve stopping time T _s is supplied to the coils in the initial driving
May be changed according to Further, in the above embodiment, since the zero lash adjuster 40 leaks down when the ignition is off, the current value to each coil is determined according to the time when the ignition is off. However, as a state in which the leak-down of the zero-lash adjuster 40 occurs, a state in which the electromagnetically driven valve 10 has stepped out in addition to the ignition-off state can be considered. Thus, the elapsed time from when the step-out is detected by the valve stopping time T _s, the actual dynamic interval after recovery from desynchronization, current may be used in accordance with the elapsed time T _s.

The step-out can be detected, for example, by comparing a command current to the upper coil 58 or the lower coil 62 with a current (actual current) actually flowing through each coil. That is, when the armature 56 is not in contact with the upper core 60 or the lower core 64 (that is, when step-out occurs), the inductance of each coil is smaller than in the case where it is in contact, and the actual current with respect to the command current is smaller. Follow-up performance becomes higher. Therefore, for example, the presence or absence of step-out can be detected based on a change in the actual current when the supply of the holding current I _H is cut off.

Next, a fourth embodiment of the present invention will be described. In the present embodiment, the command current for each coil is set according to the hydraulic pressure supplied to the zero lash adjuster 40 (hereinafter, referred to as supply hydraulic pressure P). As described above, since the hydraulic pump 83 operates using the rotation of the output shaft of the internal combustion engine as a power source, it takes some time until the discharge pressure of the hydraulic pump 83 reaches the desired pressure after the internal combustion engine is started. . Also, a delay time due to the transmission of the hydraulic pressure occurs before the discharge pressure of the hydraulic pump 83 is supplied to the zero lash adjuster 40. For this reason, after the initial drive is completed and the armature 56 and the valve body 12 are held at the fully closed position, sufficient hydraulic pressure is not supplied to the zero lash adjuster 40 for a certain period, and tappet clearance occurs. .

FIG. 19 shows (A) a time change of the engine speed before and after the ignition switch is turned on, and (B)
Time change of the supply hydraulic pressure P to the zero lash adjuster 40, (C) Time change of the tappet clearance, (D) Time change of the attraction current I _{A2 to} the upper coil 58, and (E) Time change of the attraction current I _{A1 to} the lower coil 62 Are respectively shown. As shown in FIG. 19A, at time t0
After the ignition switch is turned on, the engine speed rises in response to the start of combustion through cranking. The hydraulic pump 8
As the discharge pressure of No. 3 increases, the oil pressure P supplied to the zero-rush adjuster 40 also increases as shown in FIG. Then, as shown in FIG. 19C, the tappet clearance gradually decreases with an increase in the supply oil pressure P, and a zero rush state is realized at time t1.

As described above, the zero lash adjuster 40
In view of the fact that the tappet clearance decreases in accordance with an increase in the supply oil pressure P to the zero-rush adjuster 40 in the present embodiment, a hydraulic sensor for detecting the oil pressure in the oil supply passage 80 or 82 is provided. detecting the oil pressure P, as shown in FIG. 19 (D) and (E), in accordance with the supply pressure P, typically a suction current I _a to the lower coil 62 with increased than normal suction current I _a for upper coil 58 Decrease than time.

FIG. 20 is a flowchart of a routine executed by the ECU 11 to determine an attraction current to the upper coil 58 and the lower coil 62 in this embodiment. The routine shown in FIG. 20 is started at predetermined time intervals. When the routine shown in FIG. 20 is started, first, the process of step 500 is executed. In step 500, the hydraulic pressure P supplied to the zero lash adjuster 40 is detected.

In step 502, the deviation ΔP between the supply oil pressure P and a predetermined reference pressure P0 (the oil pressure to be supplied to the zero lash adjuster 40 in order to realize a zero rush state).
(= P0-P) is calculated. In step 504, it is determined whether the deviation ΔP is positive. As a result, ΔP
If> 0 is satisfied, the process of step 506 is executed next. On the other hand, if ΔP> 0 is not satisfied in step 504, the process of step 508 is executed next.

In step 506, based on the deviation ΔP
Attraction current I to lower coil 62 _ACorrection value ΔI
₁(<0) is determined, and in the following step 510, the deviation
Attraction current I to upper coil 58 based on ΔP_A
Correction value ΔI_Two(> 0) is determined. Step 510
When the process is completed, the process proceeds to step 512. Steps
At 512, the attraction current I to the lower coil 62_A1Is I
_A1= I_A1_Base + ΔI₁Is calculated as
At 514, the attraction current I to the upper coil 58_A2But
I_A2= I_A2_Base + ΔI_TwoIs calculated as Steps
When the processing of 514 ends, the current routine ends.
You. The reference value I_A1_Base and I_A2_Base is
The lower coil when the zero rush condition is realized.
Current I to the coil 62 and the upper coil 58_AIn
You.

FIG. 21 is an example of a map referred to in steps 506 and 510 to determine the correction values ΔI ₁ and ΔI ₂ . The map shown in FIG. 21 shows that, for various deviations ΔP, the optimum attractive current I
_A is experimentally determined in advance, and their values and the reference value I _A1 _base
And I _A2 _base. As shown in FIG. 21, the correction value ΔI ₂ is set to be larger and the correction value ΔI ₁ is set to be smaller as ΔP is larger.

On the other hand, in step 508, the correction value Δ
After I ₁ is set to “0” and the correction value ΔI ₂ is set to zero in the subsequent step 516, the processing of step 512 is executed. Therefore, if the deviation [Delta] P ≦ 0 is satisfied, i.e., if the supply pressure P is the reference pressure P0 above, the lower coils 62 and the attracting current I _A for the upper coil 58, respectively reference values I _A1 _base and I _A2
_Base is used.

As described above, in the present embodiment, the lower the oil pressure P supplied to the zero-lash adjuster 40 (ie, the larger the deviation ΔP), the more the armature 56 is moved to the lower core 64.
In view of the displacement toward the side, the larger the deviation ΔP is, the smaller the attraction current I _A1 to the lower coil 62 is set and the more the attraction current I _A2 to the upper coil 58 is set. Therefore, according to this embodiment, it is possible to supply the full open position and the optimum attracting current I _A in order to drive to the fully closed position, respectively the lower coil 62 and upper coil 58 the armature 56, thereby, the electromagnetic valve Ten reliable operations can be realized.

Next, a fifth embodiment of the present invention will be described. As shown in FIG. 19 referred to in the fourth embodiment, the supply oil pressure P increases with the lapse of time after the ignition is turned on, and the tappet clearance gradually decreases accordingly. Therefore, in this embodiment, instead of determining the attraction current to the coils in accordance with the supply pressure P, as determining the attraction current to the coils in accordance with the elapsed time after the ignition is turned on T _g I have.

[0096] Figure 22, in this embodiment, is a flowchart illustrating a routine that ECU11 executes to determine the attracting current I _A for upper coil 58 and lower coil 62. In the routine shown in FIG. 22, steps for performing the same processes as those in the routine shown in FIG. 20 are denoted by the same reference numerals, and description thereof will be omitted. The routine shown in FIG. 22 is started at predetermined time intervals. When the routine shown in FIG. 20 is started, first, the process of step 600 is executed.

[0097] At step 600, the elapsed time T _g of the after the ignition switch is turned on is detected. In step 602, the elapsed time _Tg and the predetermined reference time T0
Deviation ΔT (= time required until zero rush state is realized after ignition is turned on) (= T0−T _g )
Is calculated.

At step 604, the deviation ΔT is positive.
Is determined. As a result, when ΔT> 0 holds,
If so, the process of step 606 is executed next. on the other hand,
If ΔT> 0 is not satisfied in step 604, the next
Then, the process of step 508 is executed. Step 606
Then, the suction to the lower coil 62 is performed based on the deviation ΔT.
Current I _ACorrection value ΔI₁(<0) is determined and
In step 608, the upper coil 58
Current I_ACorrection value ΔI_Two(> 0) is determined
It is. When the processing of step 608 ends, step 5
Proceed to 12.

FIG. 23 is an example of a map which is referred to in steps 606 and 610 to determine the correction values ΔI ₁ and ΔI ₂ . The map shown in FIG. 23 shows the optimum attraction current I for each coil for various deviations ΔT.
_A is experimentally determined in advance, and their values and the reference value I _A1 _base
And I _A2 _base. As shown in FIG. 23, the correction value ΔI ₁ is set to be smaller and the correction value ΔI ₂ is set to be larger as ΔT is larger.

[0100] As described above, in this embodiment, as the elapsed time T _g of the post-ignition is turned on is short (that is, the deviation Δ
Higher T is large), the tappet clearance is increased, in view of the position of the armature 56 is lower core 64 side, the attraction current is set small the I _A1 to the lower coil 62 as the deviation ΔT is large, the attraction current for the upper coil 58 I _A2 is set small. For this reason, according to the present embodiment, the valve body 12 can be reliably opened and closed without requiring a hydraulic pressure sensor for detecting the hydraulic pressure of the oil supply passages 80 and 82.

[0102] Incidentally, in the fourth and fifth embodiments, the attraction current was assumed to I _A alone is changed, as in the case of the first to third embodiments, attracting current I _A with the holding current I _H may be changed. In the fourth and fifth embodiments, the hydraulic pump 83 has been described as operating with the rotation of the output shaft of the internal combustion engine as the power source. However, also in the case where the hydraulic pump 83 is an electric pump operated by using a battery as a power source, the discharge pressure does not sufficiently rise immediately after the ignition is turned on, so that the supply hydraulic pressure is the same as in the fourth and fifth embodiments. by changing the attracting current I _a in accordance with the P or elapsed time after the ignition is turned on T _g, it can be carried out properly the opening and closing of the valve element 12.

In the first to fifth embodiments, the command current value to each coil is changed according to the position of the armature 56, but the present invention is not limited to this. The energization time to each coil may be changed. In the first to fifth embodiments, the drive circuit 65 supplies a command signal to the upper coil 58 and the lower coil 62 in accordance with a control signal given from the ECU 11 so that the energizing means described in the claims can be used. The ECU 11 executes steps 304, 308, 310, 318 of the routine shown in FIG.
322, 324, step 40 of the routine shown in FIG.
2. Steps 506 and 510 of the routine shown in FIG.
By executing steps 512, 514, or steps 606, 608, 512, 514 of the routine shown in FIG. 22, the energization amount changing means described in the claims is realized. In addition, the ECU 11 controls the gap sensor 1
The output voltage V of 50,152, the output signal of the gap sensor 250, or by detecting the position of the armature 56 on the basis of the output signal of the laser distance sensor 260, or, ECU 11 the valve stopping time T _s or supply pressure P , The relative position related value detecting means described in the claims is realized. That is, in the first to fifth embodiment, the position of the armature 56, the valve stopping time T _s, and the supply pressure P is equivalent to the relative position related values as set forth in the appended claims.

[0103]

According to the first aspect of the present invention, even when the position of the armature changes due to insufficient hydraulic pressure supplied to the hydraulic zero lash adjuster, the required electromagnetic force is applied to the armature. Appropriately, the opening and closing drive of the valve element can be reliably performed.

According to the second to fourth aspects of the present invention, the amount of power to the electromagnet is set in accordance with the relative position between the armature and the electromagnet, so that the electromagnetic force applied to the armature can be more appropriately controlled. can do.

[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 an enlarged cross-sectional view of a zero lash adjuster included in the electromagnetically driven valve of the present embodiment and a peripheral portion thereof.

FIG. 3A is a diagram showing a waveform of a command current supplied to an upper coil in the electromagnetically driven valve of the present embodiment. FIG. 3B is a diagram illustrating a waveform of a command current supplied to the lower coil in the electromagnetically driven valve of the present embodiment. FIG. 3C is a diagram showing a lift waveform of the valve body when the command current shown in FIGS. 3A and 3B is supplied to each coil.

FIG. 4 is a diagram illustrating the relationship between the position of the armature and the electromagnetic force acting on the armature toward the lower core when the current supplied to the lower coil changes to large, medium, and small.

From Figure 5 the position of the armature, a map referred to determine the command current I _L and I _U of the lower coil and upper coil in the initial driving.

FIG. 6 is an exploded perspective view showing a configuration for detecting a position of an armature in the embodiment.

7 is a cross-sectional view of the configuration shown in FIG. 6 cut along the axial direction of the valve shaft.

FIG. 8 is a diagram showing a change in a positional relationship between a gap sensor and a concave portion provided on a valve shaft when the valve body is displaced from a fully closed position to a fully opened position.

FIG. 9 is a diagram showing a relationship between a position of a valve body and an output voltage V of a gap sensor.

FIG. 10 shows a lower coil in an initial drive according to the embodiment.
And command current I to upper coil _LAnd I_UShould decide
4 is a flowchart of a routine executed by the ECU.

FIG. 11 is an example of a configuration in which the position of the armature 56 is directly detected by a gap sensor.

FIG. 12 is an example of a configuration in which the position of the armature 56 is directly detected by a laser distance sensor.

FIG. 13A is a diagram showing the electromagnetically driven valve when the armature and the valve element are at the fully open position under the condition where the zero rush state is realized. FIG. 13B is a diagram illustrating the electromagnetically driven valve when the armature and the valve body are at the fully open position in a state where the zero rush state is not realized.

FIG. 14A is a diagram showing a waveform of a command current supplied to an upper coil in a second embodiment of the present invention. FIG. 14B is a diagram showing a waveform of a command current supplied to the lower coil in the second embodiment of the present invention.

FIG. 15 is a diagram illustrating an example in which after the initial driving is completed,
5 is a flowchart of a routine executed by an ECU to drive the valve body 12 to open and close.

FIG. 16 is a diagram showing the relationship between the valve stop time T _s and the amount of displacement from the neutral reference position of the armature to the lower core side.

FIG. 17 shows a valve stop time T according to a third embodiment of the present invention.
₆ is a map referred to for determining the attraction currents I _A1 and I _A2 and the holding currents I _H1 and I _H2 for the lower coil and the upper coil based on S.

FIG. 18 is a flowchart of a routine executed by the ECU to determine the attraction currents I _A1 and I _A2 and the holding currents I _H1 and I _H2 in the present embodiment.

FIG. 19A is a diagram showing a change over time of the engine speed after the ignition is turned on. FIG.
(B) is a diagram showing a change over time of the supply oil pressure P to the zero lash adjuster after the ignition is turned on. FIG.
FIG. 9 (C) is a diagram illustrating a temporal change in tappet clearance after the ignition is turned on. FIG. 19D is a diagram showing a time change of the attraction current to the lower coil after the ignition is turned on in the fourth embodiment of the present invention. FIG. 19E is a diagram showing a time change of the attraction current to the upper coil after the ignition is turned on in the fourth embodiment of the present invention.

FIG. 20 is a flowchart of a routine executed by the ECU to determine an attraction current for each coil in the present embodiment.

FIG. 21 is a map referred to for determining the correction values ΔI ₁ and ΔI ₂ of the attraction current from the deviation ΔP in the present embodiment.

FIG. 22 is a flowchart of a routine executed by the ECU to determine an attraction current for each coil in the fifth embodiment of the present invention.

FIG. 23 is a map referred to for determining the correction values ΔI ₁ and ΔI ₂ of the attraction current from the deviation ΔT in the present embodiment.

[Explanation of symbols]

 Reference Signs List 10 electromagnetic drive valve 11 electronic control unit (ECU) 12 valve element 40 zero lash adjuster 42 armature shaft 56 armature 58 upper coil 60 upper core 62 lower coil 64 lower core 65 drive circuit 150, 152, 250 gap sensor 260 laser distance sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16K 1/32 F16K 1/32 A 31/06 305 31/06 305Z 310 310A 385 385A (72) Inventor Matsumoto Isao 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Masaaki Tanaka 1 Toyota Town Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Keiji Yoeda Toyota Town Toyota City, Aichi Prefecture No. 1 Toyota Motor Corporation (72) Inventor Hideyuki Nishida 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3G016 AA05 AA18 BA36 BB31 BB40 DA18 DA22 DA23 DA25 GA04 3G092 AA11 DA01 DA02 DA07 DF04 DG02 DG09 EA12 EA13 EA17 EA28 EA29 EB08 GA01 HA13Z HE00X HE00Z 3G301 HA19 JA17 JA37 LA07 LC02 LC08 ND 06 NE23 PE00Z PE10Z PG02A 3H052 AA01 CD02 EA16 3H106 DA07 DA25 DB02 DB12 DB26 DB32 DC02 DD06 EE05 EE20 FA01 FA08 FB11 KK17

Claims (4)

[Claims] 1. A valve body, an armature interlocked with the valve body, an electromagnet for applying an electromagnetic force to the armature, and a hydraulic pressure supplied between the valve body and the armature. In an electromagnetically driven valve including a zero lash adjuster that extends following a change in the distance between the valve element and the armature, and an energizing unit that energizes the electromagnet, hydraulic pressure supply to the zero lash adjuster is started. Thereafter, for a predetermined period, an electromagnetically driven valve including an energization amount changing unit that changes an energization amount to the electromagnet by the energization unit with respect to a normal time. 2. The apparatus according to claim 1, further comprising: a relative position-related value detecting unit configured to detect a relative position-related value corresponding to a relative position between the armature and the electromagnet. 2. The electromagnetically driven valve according to claim 1, wherein an amount of current to the electromagnet is set. 3. The electromagnetically driven valve according to claim 2, wherein the relative position related value is an elapsed time from when the supply of the hydraulic pressure to the zero lash adjuster is stopped to when it is restarted. 4. The electromagnetically driven valve according to claim 2, wherein the relative position related value is a hydraulic pressure value supplied to the zero lash adjuster.