JPH09195736A - Operating method of solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of actuating a solenoid valve, for improving responsiveness, power saving, and adaptability to supply voltage. SOLUTION: A resonance phenomenon is used at the starting zone to save power consumption. In the holding zone a plunger is positively attracted by the current flowed in an upper coil with a surplus by Δt1 . In the zone of Δt2 after lapse of Δt1 and up to the start of actual operation, only the current required for attracting and retaining the plunger is supplied so that the movement of plunger at the start of actual operation is performed in good responsiveness. In the actual operation zone, by attracting the plunger to the lower core or to the upper core in the course of decrease of the current from an attraction current to a retention current, the attraction movement of the plunger is performed gently in the state that the attraction force is decreased. The power consumption in attraction and retention during the actual operation zone is reduced by supplying the minimum current required for attraction and retention of the plunger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating an electromagnetic valve that controls its drive by an electromagnetic force, and more particularly, to a method of operating a solenoid valve that utilizes a resonance phenomenon at the time of starting.

[0002]

2. Description of the Related Art Conventionally, as an intake / exhaust valve of an internal combustion engine, a valve which is opened / closed by a camshaft driven based on rotation of a crankshaft is generally used. And
From the viewpoint of improving the performance of an internal combustion engine, various variable mechanisms of a valve operating system are being put into practical use in order to achieve an optimal valve opening / closing timing according to an operating state.
/ OFF control type) and continuously variable types have also been developed. These variable mechanisms include those that shift the rotation phase of the camshaft and those that have a plurality of cam profiles on the camshaft.

However, in the intake / exhaust valve driven by the camshaft as described above, it is impossible to independently and arbitrarily set the valve lift amount, the valve opening time, and the opening / closing timing. Therefore, in recent years, in order to meet the demand for higher performance of the internal combustion engine, research on an electromagnetically driven valve train that can set those parameters to ideal values according to the operation state has been activated. I have.

For example, in Japanese Patent Laid-Open No. 59-213913, the plunger is moved by electromagnetic force in the opening direction or the closing direction of the valve from a neutral position where the forces of springs provided on both sides of the plunger connected to the valve balance. It discloses a solenoid valve, in particular a method for starting it. The starting method is to utilize the resonance phenomenon in order to save power.

That is, according to the teaching of physics, in a spring-mass system, neglecting friction and other losses, if an initial displacement is given, a continuous sinusoidal vibration of a natural frequency is generated, and further, If an external force that vibrates in accordance with its natural frequency is continuously applied to the mass, its amplitude will gradually increase without limit. In the starting method according to the above publication, an electromagnetic force is applied as an external force to a spring-mass system including a plunger as a mass to excite natural vibration (self-excited vibration), and finally one of the electromagnets is attracted to start the starting operation. To complete. By utilizing such a resonance phenomenon, it is possible to reduce the electromagnetic force at the time of starting, and thus the initial current for generating the electromagnetic force, and as a result,
Power saving can be achieved at the time of starting.

[0006]

In the starting method according to the above-mentioned prior art, even after the plunger is attracted to one electromagnet, the current value that excites the natural vibration is maintained as it is and the attracted state of the plunger is maintained. After that, the current is cut off, and the current supply pattern for executing the opening / closing operation of the valve is started. However, the current to be supplied at the time of natural vibration needs to be a large value according to the required valve lift amount. Therefore, as described above, when the current during natural vibration that is maintained even in the adsorption and holding state is interrupted and an attempt is made to induce reverse operation, when the current is large, the residual magnetism is also large and A large electromagnetic force, and thus an electric current, is required to induce actuation. If a sufficient current cannot flow, it is impossible to secure sufficient operability in the reverse direction. As described above, the starting method according to the related art has a problem that the operation response at the time of starting the opening / closing operation after starting is poor.

In addition, the above-mentioned prior art is intended to save power until the plunger is attracted to one of the electromagnets at the time of starting. Regarding power saving after attraction at the time of starting and power saving at the time of actual operation. Did not disclose anything.

Further, when the electromagnetic valve is applied to an internal combustion engine (engine), when the engine is started, the power supply to the electromagnetic valve must depend on the battery, but as is well known, the battery is used. The voltage drops due to aging, and also drops at extremely low temperatures. Therefore, under such conditions, it is impossible to always supply a constant current at the time of starting. However, the above-mentioned prior art does not disclose even a starting method according to such a situation.

In view of the above situation, an object of the present invention is to provide a method of operating an electromagnetic valve, which has improved operation response, reduced power consumption, and operated suitable for supply voltage.

[0010]

A method for operating an electromagnetic valve according to the first invention of the present application, which has been devised to achieve the above-mentioned object, includes a force of a spring provided on both sides of a plunger connected to the valve. Is a method of operating an electromagnetic valve that moves the plunger in one direction or the other by electromagnetic force from a neutral position where is balanced, and a starting section in which the plunger self-excitedly vibrates by the electromagnetic force formed by the first current value, After adsorbing the plunger whose amplitude is increased by the self-excited vibration in one direction,
A holding section that attracts and holds in one direction by an electromagnetic force formed by a second current value that is smaller than the first current value, and a third current value from one direction to the other direction or from the other direction to the one direction. A step of moving the plunger by the electromagnetic force formed, a step of adsorbing the plunger in the other direction or in one direction while decreasing from the third current value to a fourth current value smaller than the third current value. And a step of actually attracting and holding the plunger in the other direction or in one direction by the electromagnetic force formed by the fourth current value.

Further, a method of operating an electromagnetic valve according to a second aspect of the present invention is the method according to the first aspect of the present invention, wherein the time of the current when the third current value decreases to the fourth current value. The change rate of the current is changed according to the environment in which the solenoid valve is used, and the change rate of the current with time when the first current value is decreased to the second current value is changed by the use of the solenoid valve. It is characterized in that it does not change depending on the environment in which it is used.

A method for operating an electromagnetic valve according to a third aspect of the present invention is the method according to the first aspect, wherein the lower the voltage of the supply source is, the smaller the first current value is set and the starting is performed. The feature is that the interval is set to be long.

According to the solenoid valve actuation method of the first aspect of the invention configured as described above, the current is reduced from the first current value to the second current value in the holding section. Power saving in the holding section is achieved. Also,
After the current decreases to the second current value, that is, after the electromagnetic force decreases, it shifts to the actual operation section, so that the residual magnetism decreases and the plunger held in one direction is moved to the other direction. The movement will be performed with good responsiveness. Also,
Since the change from the first current value to the second current value is performed after the plunger is adsorbed, the adsorption error at the time of starting is surely avoided. Further, in the actual operation section, while the current decreases from the third current value to the fourth current value,
That is, since the plunger is attracted while the electromagnetic force (attractive force) is weakened, the plunger is attracted and the valve is seated gently.

According to the method according to the second aspect of the present invention, the temporal change rate of the electric current when the third electric current value decreases to the fourth electric current value depends on the environment in which the solenoid valve is used. The rate of change can be changed. The first
Since the decrease from the current value of to the second current value is a mere transition to the holding current after adsorption, there is no problem even if it is executed in a short time regardless of the environment used, and by doing so, The consumption current can be reduced.

When the voltage of the supply source is low, the current value for exciting the self-excited vibration must be reduced in the starting section, so that the electromagnetic force becomes small and, as a result, the increase rate of the amplitude becomes slow. In order to deal with this, it is necessary to lengthen the self-excited vibration time, that is, the starting section. According to the method of the third aspect of the present invention, when the voltage of the supply source is high, the start section can be set short and the start-up state can be quickly changed, while when the voltage of the supply source is low, the start section can be lengthened. It is possible to set and surely shift the valve to the start-up completed state.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of an electromagnetic valve according to an embodiment of the present invention as an intake / exhaust valve of an internal combustion engine. The valve body 1 shown in the figure opens and closes the intake / exhaust port 2 by seating on or detaching from the valve seat 3 provided in the intake / exhaust port 2 of the internal combustion engine. A valve shaft 4 is fixed to the valve body 1. This valve shaft 4 has a valve guide 5
Is held by the shaft so as to be slidable in the axial direction. A plunger 6 is fixed to the valve shaft 4.

The plunger 6 is a disk-shaped member made of a soft magnetic material. An upper core 7 is arranged above the plunger 6 at a predetermined distance, and a lower core 9 is also arranged below the plunger 6 at a predetermined distance. There is. The upper core 7 and the lower core 9 are made of a soft magnetic material, and are held in a predetermined positional relationship by a case 11 made of a nonmagnetic material. The upper core 7 holds an upper coil 8 and the lower core 9 holds a lower coil 10.

The valve shaft 4 has an upper spring 12
The lower spring 13 elastically supports the lower spring 13 in the axial direction. Then, the upper spring 12 and the lower spring 13 are balanced so that the position (neutral position) of the plunger 6 when the upper coil 8 and the lower coil 10 are not energized is an intermediate position between the upper core 7 and the lower core 9. Is being pursued. When the plunger 6 is in the neutral position, the valve body 1 is located at an intermediate position between the fully open side displacement end and the fully closed side displacement end.

According to this structure, a magnetic circuit composed of the upper core 7, the plunger 6 and the air gap formed between them is formed around the upper coil 8. Therefore, when a current is passed through the upper coil 8, a magnetic flux flows back through the magnetic circuit, and an electromagnetic force is generated in a direction that reduces the air gap, that is, a direction that displaces the plunger 6 upward. On the other hand, around the lower coil 10, a magnetic circuit including the lower core 9, the plunger 6 and an air gap formed between them is formed. Therefore, when a current is applied to the lower coil 10, an electromagnetic force is generated in the direction of displacing the plunger 6 downward, based on the same principle.

Thus, by alternately passing a current through the upper coil 8 and the lower coil 10, it becomes possible to reciprocate the plunger 6 up and down, that is, to drive the valve body 1 alternately in the opening and closing directions. The electronic control unit (ECU) 20 determines the opening / closing timing of the electromagnetic valve based on signals from various sensors (not shown), and controls the energization of the upper coil 8 and the lower coil 10 to operate the electromagnetic valve. It works.

When the plunger 6 is at the displacement end on the fully closed side, the plunger 6 and the valve seat 3 should be in close contact with each other.
And the upper core 7 form a minute clearance. On the other hand, when the plunger 6 is at the fully open side displacement end, the plunger 6 and the lower core 9 are in close contact with each other.

FIG. 2 is a time chart showing temporal changes in the current of the upper coil 8, the current of the lower coil 10, and the valve lift amount. It should be noted that as the current, both a command value (solid line) given by the ECU 20 and a monitor value (broken line) actually flowing in the coil are shown. As shown in this figure, the electromagnetic valve actuation method of the present invention can be divided into three sections, a starting section, a holding section, and a working section.

First, in the starting section, the resonance phenomenon is utilized in order to save power as described above. That is, depending on the natural frequency of the spring-mass system including the plunger as the mass, as shown in FIGS. 7A and 7B, the self-excited vibration of the valve is generated around the neutral position in the non-energized state. With a different cycle (Δt × 2), a current (hereinafter, the current in the starting section is referred to as a starting current (first current)) is alternately applied to the upper coil 8 and the lower coil 10 for Δt time.
Then, the valve gradually increases in amplitude from the neutral position, as shown in FIG. Thus, by utilizing the resonance phenomenon, it is possible to reduce the electromagnetic force at the time of starting, and therefore the starting current for generating the electromagnetic force, and as a result, it is possible to save power at the time of starting,
The circuit configuration is also simplified.

Finally, in the holding section, the plunger 6 is attracted to the upper core 7 side and the valve is closed. In this holding section, the energization time Δt in the starting section
In addition, an additional current is passed through the upper coil 8 by Δt ₁ . As a result, it is possible to avoid a situation where the acceleration of the plunger 6 becomes too large and the plunger 6 bounces due to the collision between the plunger 6 and the upper core 7 and the plunger 6 is not sucked.

After the lapse of Δt ₁ to the start of the actual operation section, as shown in the Δt ₂ part of FIG. 7A, the minimum holding and holding of the plunger 6 is required to reduce the extra power consumption. The necessary current (hereinafter referred to as the holding current (second current)) continues to flow. Further, since the current value decreases from the starting current to the holding current, that is, after the electromagnetic force decreases, the operation section is moved to, so that the movement of the plunger at the start of actual operation is performed with good responsiveness. . Since the reduction from the starting current to the holding current is done after the plunger is attracted, the environment in which the solenoid valve is used (for example,
There is no problem even if it is executed in the shortest possible time regardless of the engine temperature, the cranking speed, etc.), and by doing so, the current consumption can be reduced accordingly.

In the actual operation section, as shown in FIGS. 2 (A) and 2 (B), electric currents are alternately applied to the lower coil 10 and the upper coil 8 to achieve the vertical operation of the valve. As shown in detail in FIG. 3, the current flowing in the actual operation section is a process a in which a current is supplied to move the plunger 6 (hereinafter, the current in this process is referred to as a suction current (third current)), The process b in which the current value decreases from the attracting current to the holding current (which may be the same value as the holding current in the holding section, but may be a different value, and is therefore called the fourth current) at a certain temporal change rate, and It is composed of a process c in which a holding current is passed to attract and hold the plunger.

By allowing the plunger 6 to be attracted to the lower core 9 or the upper core 7 during the step b, the plunger 6 is attracted and the valve element 1 is seated while the electromagnetic force (attraction force) is weakened. Is done slowly. The setting of the processes a, b and c will be described later in detail. In addition, since the minimum necessary current for holding the plunger 6 by suction, that is, the holding current is supplied even during the suction holding in the actual operation section, power saving is achieved also in the actual operation section.

By the way, in the internal combustion engine for automobiles,
There is no choice but to use a battery as a source of starting current. In that case, it must be taken into consideration that the battery voltage drops when the battery deteriorates or when the temperature is low. That is, by measuring the battery voltage and determining the starting current value (command value) and the length of the starting section according to the voltage value, it is possible to surely complete the starting even at a low voltage. The details will be described with reference to FIG.

FIG. 4 is a time chart showing temporal changes in the upper coil current, the lower coil current, and the valve lift amount when the battery voltage is high (A) and low (B). As shown in this figure, when the battery voltage is low, the starting current value must be reduced, so that the electromagnetic force is reduced, and as a result, the increase rate of the valve lift amplitude is slowed. To cope with this, the self-excited vibration time, that is, the starting section is set to be long, and as a result, the valve can be reliably shifted to the starting completed state. On the other hand, when the battery voltage is high, the starting section is set to be short, and the starting completion state can be moved more quickly.

FIG. 5 shows an electronic control unit (ECU) 20.
3 is a flowchart showing a control flow by the. First,
When the ignition key is turned on, the crank angle sensor is operated and the sensor output is input to confirm which cylinder is at top dead center (step 102). Then, the cranking rotation speed Ne is input (step 10).
4). Next, a valve start calculation is executed (step 10).
6). In this valve starting calculation, the battery voltage is measured, and as described above, the starting current value (command value) and the length of the starting section are determined based on the measured value to start the electromagnetic valve,
After the start section has elapsed, the process moves to the holding section.

Next, the basic actual operating opening timing of the solenoid valve is determined from the piston top dead center position and the cranking rotation speed Ne, and the solenoid valve is actually operated (step 108). At this time, the operation of the fuel injection valve and the spark plug is also started. In the next step 110, the operation of the electromagnetic valve is confirmed by detecting the displacement of the electromagnetic valve by the position sensor. If the operation is not confirmed, the process proceeds to step 112, and if the operation is confirmed, the step 116 is performed. Proceed to.
In step 112, the valve start mode is set again, and in the next step 114, an abnormal signal is output and then the process loops back to step 102.

On the other hand, after step 116, the process for obtaining the current pattern in the actual operation section is executed. First, at step 116, the engine speed Ne and the engine load L
Input i, intake air temperature, oil temperature, and water temperature Ti. Then
In step 118, the water temperature Ti is a predetermined determination reference value T _0.
It is determined whether or not it is larger than Ti. If Ti> T ₀ , the process proceeds to step 120, and if Ti ≦ T ₀ , step 12
Proceed to 2.

In step 120, it is judged whether the engine load Li is larger than a predetermined judgment reference value L ₀ , and Li
When> L ₀ , the routine proceeds to step 126, and when Li ≦ L ₀ , the routine proceeds to step 124. Also in step 122, similarly, the engine load Li is equal to the predetermined determination reference value L.
_It is determined whether or not it is greater than _{0. If} Li> L ₀ , the process proceeds to step 130, and if Li ≦ L ₀ , the process proceeds to step 1
Proceed to 28.

Then, in step 124, the current patterns of the low temperature low load mode, the step 126 low temperature high load mode, the step 128 high temperature low load mode, and the step 130 high temperature high load mode are set. Less than,
Each current pattern in these modes will be described in detail separately for the upper coil current and the lower coil current.

FIG. 6 shows the upper coil 8 in the actual operation section.
It is a figure which shows the typical pattern of the electric current applied to. As can be seen from this figure, the suction current (peak current) value, the suction current application time, and the transition time from the suction current to the holding current are the same in any mode. However, the holding current value is different in each mode (therefore, the temporal change rate of the current when the suction current value is decreased to the holding current value is different). The reason for doing this is as follows.

First, the extension of the cylinder head for fixing the upper core 7 in the valve axis direction is small at low temperature and large at high temperature. Further, the extension of the valve shaft fixing the plunger 6 is small at low load and large at high load. Therefore, considering the clearance between the upper coil 7 and the plunger 6, in the low temperature and high load mode, the head extension is “small” and the valve shaft extension is “large”, and therefore the clearance is “small”, and therefore, FIG. As shown in (B), the holding current can be reduced.

In the high temperature and low load mode, the head extension is "large" and the valve shaft extension is "small", so the clearance is "large". Therefore, as shown in FIG. Need to be bigger. In the low temperature low load mode, the head extension is “small” and the valve shaft extension is “small”. On the other hand, in the high temperature high load mode, the head extension is “large”.
Since the valve shaft extends at “large”, the clearance can be considered to be “medium”. Therefore, as shown in FIGS. 7A and 7D, the magnitude of the holding current is “medium”. can do.

As described above, with respect to the upper coil current, the transition time from the attracting current to the holding current is constant, but the temporal change rate of the upper coil current is between the upper core and the plunger depending on the environment in which the solenoid valve is used. The clearance is changed in consideration of the change in the clearance, and as a result, the plunger can be held securely and it is not necessary to supply an excessive holding current.

FIG. 7 shows the lower coil 10 in the actual operation section.
It is a figure which shows the typical pattern of the electric current applied to. As can be seen from this figure, the holding current and the transition time from the attracting current to the holding current are the same in any mode. However, the current application start timing, the suction current (peak current) application time, and the suction current (peak current) value differ depending on the mode. As shown in FIGS. 7B and 7D, the reason why the current application start timing is early when the load is high is that the cylinder pressure increases as the load increases.

Further, as shown in FIGS. 7A and 7B, the reason why the current application start timing is early when the temperature is low is that the sliding resistance of the valve due to the viscosity increases as the temperature lowers. Further, as shown in FIGS. 7B and 7D, the reason why the suction current application time is long when the load is high is that the cylinder pressure increases as the load increases. Further, as shown in FIGS. 7B and 7D, the reason why the suction current value is large when the load is high is that the cylinder pressure also increases as the load increases.

Therefore, also in the lower coil, the temporal change rate of the current from the attracting current to the holding current is changed depending on the environment in which the solenoid valve is used.

Although the embodiments of the present invention have been described above, of course, the present invention is not limited to these, and it will be easy for those skilled in the art to devise various embodiments.

[0044]

As described above, according to the present invention,
Provided is a method of operating a solenoid valve, which has improved operation response, power saving, and operation suitable for supply voltage. That is, according to the method of the first aspect of the present invention, the movement of the plunger is performed with good responsiveness when shifting from the starting section to the actual operation section, and further, the adsorption of the plunger is gently performed in the actual operation section. Along with this, power saving is achieved.

Further, according to the method of the second aspect of the present invention, power saving can be achieved by shifting to the holding current at the time of starting regardless of the environment in which the electromagnetic valve is used.

According to the method of the third aspect of the present invention, when the voltage of the supply source is high, it is possible to quickly shift to the start completion state, while when the voltage of the supply source is low, the start completion state is surely achieved. Can be transferred.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a solenoid valve according to an embodiment of the present invention.

FIG. 2 is a time chart showing temporal changes in an upper coil current, a lower coil current, and a valve lift amount.

FIG. 3 is a diagram showing a current pattern in an actual operation section.

FIG. 4 is a time chart illustrating temporal changes in an upper coil current, a lower coil current, and a valve lift amount when the battery voltage is high and when the battery voltage is low.

FIG. 5 is a flowchart showing a control flow by the ECU.

FIG. 6 is a diagram showing a typical pattern of an upper coil current in an actual operation section.

FIG. 7 is a diagram showing a typical pattern of a lower coil current in an actual operation section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Valve body 2 ... Intake / exhaust port of internal combustion engine 3 ... Valve seat 4 ... Valve shaft 5 ... Valve guide 6 ... Plunger 7 ... Upper core 8 ... Upper coil 9 ... Lower core 10 ... Lower coil 11 ... Case 12 ... Upper spring 13 ... Lower side spring 20 ... Electronic control unit (ECU)

Claims (3)

[Claims] 1. A method of operating an electromagnetic valve, comprising moving a plunger in one direction or another direction by electromagnetic force from a neutral position where spring forces provided on both sides of a plunger connected to the valve balance each other. A starting section in which the plunger self-excitedly vibrates by the electromagnetic force formed by the current value, and a plunger whose amplitude has increased due to the self-excited vibration are attracted in one direction, and then a second section smaller than the first current value A holding section that attracts and holds in one direction by an electromagnetic force formed by a current value, and a process of moving the plunger from one direction to another direction or from one direction to another direction by an electromagnetic force formed by a third current value, The process of adsorbing the plunger in the other direction or the one direction while decreasing from the third current value to the fourth current value smaller than the third current value, and the fourth current value Therefore, the operating method of the electromagnetic valve is characterized by comprising an actual operation section consisting of a process of attracting and holding the plunger in the other direction or the one direction by the electromagnetic force formed. 2. The time change rate of the current when the third current value decreases to the fourth current value is changed according to the environment in which the solenoid valve is used, and the first current value is changed. 2. The actuation of a solenoid valve according to claim 1, wherein the rate of change of the current with time when the value decreases from the second current value does not change depending on the environment in which the solenoid valve is used. Method. 3. The method of operating an electromagnetic valve according to claim 1, wherein the lower the voltage of the supply source is, the smaller the first current value is set and the longer the starting section is set.