JPH11324742A - Control device for electromagnetically driven valve - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To set a hold current for maintaining a fully closed or fully open state of a valve to an optimum value without being affected by variations in products, deterioration over time, and the like. After turning on an ignition switch, one of electromagnetic coils (5, 6) is energized to first fully close or fully open a valve (4), and then gradually increases a hold current for maintaining the valve (4) in a fully closed or fully open state. The output value of the valve lift sensor 10 at this time is read. Then, the hold current when the output value of the valve lift sensor 10 suddenly changes is learned as a limit value for maintaining the fully closed or fully open state of the valve 4, and thereafter, this limit value is maintained until the ignition switch is turned off. A current of 10% increase is supplied as a hold current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electromagnetically driven valve for learning a limit value of a hold current for maintaining a fully closed or fully opened state of an intake / exhaust valve.

[0002]

2. Description of the Related Art In recent years, valve operating systems that electronically control the opening and closing timing of intake and exhaust valves by performing electromagnetic opening and closing operations of the intake and exhaust valves of the engine, not mechanically by a camshaft or the like, have been developed. It has been developed and disclosed in, for example, Japanese Patent Application Laid-Open No. 8-170509 or Japanese Patent Application Laid-Open No. 8-200108.

In the electromagnetically driven valves disclosed in these prior arts, a plate-shaped armature is fixed to the upper end of a valve stem of an intake / exhaust valve, and the intake valve is urged in a valve closing direction with the armature interposed therebetween. Along with a spring and a spring that biases in the valve opening direction, a valve opening electromagnetic coil and a valve closing electromagnetic coil are disposed on the outer periphery of each spring, and when the valve closing electromagnetic coil is excited, When the armature is sucked against the urging force of the valve-opening spring and the intake / exhaust valve closes, and when the valve-opening electromagnetic coil is excited, the armature opposes the urging force of the valve-closing spring. The air is sucked and the intake / exhaust valve opens. The engine is driven by controlling the opening and closing timing of the intake and exhaust valves in synchronization with the rotation of the crankshaft.

[0004]

In order to reduce the power consumption, it is necessary that the hold current supplied to the electromagnetic coil to maintain the fully closed or fully open state of the intake and exhaust valves is minimum. Is preferred.

However, the minimum hold current required to maintain the fully closed or fully opened operation of the intake / exhaust valve differs from product to product due to variations in manufacturing of the entire valve operating system, aging, and the like. Therefore, it is difficult to set an optimum value in advance.

[0006] Therefore, the peak value of the hold current is set to a certain high value, which requires an electromagnetic drive circuit having a large capacity, which leads to an increase in power consumption.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention makes it possible to set an optimum hold current for each product in response to variations in manufacturing of a valve operating system, deterioration over time, etc. without increasing the size of an electromagnetic drive circuit. It is an object of the present invention to provide a control device for an electromagnetically driven valve which can reduce power consumption.

[0008]

In order to achieve the above object, an electromagnetically driven valve control apparatus according to the present invention comprises: an electromagnetically driven valve for driving and controlling an intake / exhaust valve interposed in an intake / exhaust port of an engine by an electromagnetic coil; A valve lift sensor is added to the intake / exhaust valve, and the hold current when the intake / exhaust valve is fully closed or fully open is gradually reduced to limit the hold current when the output value of the valve lift sensor suddenly changes. It is characterized by learning as a value.

In this case, preferably, the learning of the hold current is performed before the start of the engine.
Alternatively, after the engine is started, the hold current is adjusted based on the learned limit value.

In the control apparatus for an electromagnetically driven valve according to the present invention, the hold current when the intake / exhaust valve is fully closed or fully opened is gradually reduced, and when the output value of the valve lift sensor changes abruptly, that is, when the intake / exhaust gas is exhausted. The hold current when the valve cannot be maintained in the fully closed or fully open state is read, and the limit value of the hold current is learned to be used as a reference for the hold current control.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 5 show a first embodiment of the present invention.

Reference numeral 1 in FIG. 1 denotes an electromagnetically driven valve interposed in an intake port and an exhaust port of each cylinder of the engine. In the present embodiment, a valve stem guide 3 in which a cylinder head 2 is implanted is provided. In order to open and close a slidably supported valve 4 (an intake valve or an exhaust valve), a twin coil system in which a valve opening electromagnetic coil 5 and a valve closing electromagnetic coil 6 are arranged to face each other is adopted.

In the electromagnetically driven valve 1, the valve opening electromagnetic coil 5 is housed in the yoke 7 and disposed on the cylinder head 2 side. The valve closing electromagnetic coil 6 is connected to a yoke 9 via a lift adjuster 8 for adjusting a lift amount. Further, a guide portion for moving an armature 17 described later in the axial direction is formed on an upper portion of the yoke 9 for accommodating the valve closing electromagnetic coil 6 and a lift position for detecting a lift amount of the valve 4. A case 11 for mounting an eddy current type valve lift sensor 10, which is an example of a sensor, is joined.

A valve closing spring 13 for urging the valve head 4a of the valve 4 toward the valve seat 12 is housed inside the valve opening electromagnetic coil 5. The valve-closing spring 13 includes a retainer 15 fixed to the end of the valve stem 4b of the valve 4 via a cotter pin 14, and a receiving seat formed around the valve stem guide 3 on the cylinder head 2 side. It is interposed between. In addition, at the tip of the valve stem 4b,
A shim 16 for clearance adjustment to be described later is mounted.

In the space formed by the lift adjuster 8 of the electromagnetically driven valve 1, when the valve-opening electromagnetic coil 5 or the valve-closing electromagnetic coil 6 is excited, a magnetic force from the valve-opening electromagnetic coil 5 or the valve-closing electromagnetic coil 6 is generated. A plate-shaped armature 17 for receiving and opening and closing the valve 4 is provided.

At the center of the armature 17 on the side of the valve opening electromagnetic coil 5, an armature stem 17 a is integrally or separately provided upright, and the armature stem 17 a is provided inside the valve closing electromagnetic coil 6. The arm 11 is slidably inserted into an armature stem guide 18 provided on a cylindrical portion of the case 11 projecting from the case 11. A valve opening spring 19 for urging the valve head 4a in a direction away from the valve seat 12 is interposed between the armature 17 and a receiving portion formed at the base of the cylindrical portion of the case 11. Have been.

When both the valve-opening electromagnetic coil 5 and the valve-closing electromagnetic coil 6 are OFF, the armature 17 contacts the shim 16 at the tip of the valve stem 4b so that the valve-closing spring 13 It is stationary at a position where the urging force and the urging force of the valve opening spring 19 are balanced.

Further, the distal end side of the armature stem 17a is formed into a small needle shape and serves as a lift sensor target 17c which is an object to be detected by the valve lift sensor 10. The lift sensor target 17c Is detected by the valve lift sensor 10 as the lift of the valve 4. The valve lift sensor 10 outputs a voltage that is linear with respect to the valve lift amount.

The electromagnetically driven valve 1 having the above configuration is driven and controlled by an electromagnetic valve drive control device 30. In this electromagnetic valve drive control device 30, a microcomputer (microcomputer) 31 opens and closes the intake valve and the exhaust valve of each cylinder based on various data such as the engine speed, accelerator opening, crank angle pulse, and engine coolant temperature. And the valve closing electromagnetic coil 6 and the valve opening electromagnetic coil 5 are respectively connected to the valve closing electromagnetic coil drive circuit 3.
6. Alternately ON via valve opening electromagnetic coil drive circuit 37
Then, the valve 4 is opened and closed.

That is, in order to open the valve 4 from the closed state, the valve closing electromagnetic coil 6 is turned off and the valve opening electromagnetic coil 5 is turned on at a predetermined timing. As a result, an attractive force is generated in the valve opening electromagnetic coil 5 and the armature 1
7 moves further to the valve opening electromagnetic coil 5 side from the position where the urging force of the valve closing spring 13 and the urging force of the valve opening spring 19 are balanced, and the armature 17 is attracted to the valve opening electromagnetic coil 5 side. When stopped, the valve 4 reaches the maximum lift position (valve fully open position) and the valve opening operation is completed.

On the other hand, to close the valve 4 from the open state, the valve opening electromagnetic coil 5 is turned off, and then the valve closing electromagnetic coil 6 is turned on at a predetermined timing. In this valve closing operation, a return force to a balanced position between the urging force of the valve closing spring 13 and the urging force of the valve opening spring 19, and
The armature 17 is moved by the attraction force of the valve closing electromagnetic coil 6.
Moves to the valve closing electromagnetic coil 6 side, and finally, the armature 17 is attracted to the valve closing electromagnetic coil 6 side and stops, the armature 17 is moved to the shim 1 at the tip of the valve stem 4b.
6, a predetermined clearance is formed, and the valve head 4a is pressed against the valve seat 12 by the valve closing spring 13 to be seated (the valve is fully closed).

The electromagnetic valve drive control device 30 includes a microcomputer 31, an electromagnetic coil control circuit 33, and a hold current control circuit 35. The microcomputer 31 calculates the opening / closing timing of the intake valve and the exhaust valve of each cylinder based on various data such as the engine speed, the accelerator opening, the crank angle pulse, and the engine cooling water temperature. In addition to outputting a trigger signal indicating the start of closing or opening of the intake valve and the exhaust valve, the hold current control circuit 35
To output valve hold time data and a PWM signal for determining a holding period of the valve fully open or the valve fully closed.
In the figure, a circuit system for driving one electromagnetically driven valve 1 is shown as a representative. Actually, a circuit having the same configuration is provided after the microcomputer 31 by the number of intake and exhaust valves of the engine. As many as the number of systems are provided.

In the electromagnetic coil control circuit 33, based on a trigger signal from the microcomputer 31, a valve closing electromagnetic coil driving circuit 36 and a valve opening electromagnetic coil driving circuit 37 are supplied with a drive pulse signal at the time of valve closing or valve opening. Is output.

The valve closing electromagnetic coil driving circuit 36 and the valve opening electromagnetic coil driving circuit 37 perform overexcitation at a high voltage based on the driving pulse signal output from the electromagnetic coil control circuit 33, and perform coil excitation. When the required attraction force is secured by speeding up the rise of the current, and when the fully closed position or the fully opened position is reached, the chopper control at the rated voltage is performed based on the PWM signal output from the hold current control circuit 35. , Maintain the specified hold current.

The valve closing electromagnetic coil driving circuit 36 and the valve opening electromagnetic coil driving circuit 37 have the same configuration, and as shown in FIG.
2, a capacitor 76 is connected to the high-voltage power charger 73 via a diode 75 for charging a power supply for over-excitation (primary over-excitation) for accelerating the intake / exhaust valve at the beginning of startup. In addition, a power supply for overexcitation (secondary overexcitation) for finely adjusting the speed immediately before reaching the fully closed or fully opened state at a high voltage slightly lower than the overexcitation voltage at the initial stage of the rising through the diode 79 is charged. The capacitor 80 is connected.

The charger control section 72 operates the high voltage power supply charger 73 in response to a charge signal (a valve closing charge signal or a valve opening charge signal) from the microcomputer 31 and is connected to the output side of the high voltage power supply charger 73. Based on a signal from the charging voltage detecting unit 74, the voltage of the power supply 71 is set to a set voltage (for example, 120
V), and the capacitors 76 and 80 are charged.

The collector of the NPN type power transistor 77 is connected to the capacitor 76 for charging the power supply for the primary overexcitation, and the emitter of the power transistor 77 is connected via the diode 78 to the valve opening electromagnetic coil 5 or the valve closing valve. Connected to the electromagnetic coil 6.

The collector of an NPN type power transistor 81 is connected to a capacitor 80 for charging a power supply for secondary overexcitation.
Is connected to the valve opening electromagnetic coil 5 or the valve closing electromagnetic coil 6 via a diode 82.

Further, the collector of an NPN power transistor 83 for holding current is connected to the power supply 71, and the emitter of the power transistor 83 is connected via a diode 84 to the valve opening electromagnetic coil 5 or the valve closing electromagnetic coil. It is connected to the coil 6.

Each of the power transistors 77, 81
Is connected to an electromagnetic coil control circuit 33, and a base of the power transistor 83 is connected to a hold current control circuit 35. In the electromagnetic coil control circuit 33, a trigger signal is output to the base of the power transistor 77 in the initial section of the rising of the intake valve or the exhaust valve, and the section immediately before the intake valve or the exhaust valve is fully opened or fully closed. Then, a trigger signal is output to the base of the power transistor 81. Further, the hold current control circuit 35 outputs a PWM signal to the base of the power transistor 83 during the period when the valve is fully opened or fully closed, and outputs the PWM signal to the valve opening electromagnetic coil 5 (or the valve closing electromagnetic coil 6). Generates a hold current to be energized.

As a result, the acceleration response at the initial stage of closing or opening the intake / exhaust valve is improved, and when the valve is fully closed or fully opened, the speed is finely adjusted, so that the impact at the time of sitting is alleviated.

On the input side of the microcomputer 31, an ignition switch 40, a starter switch 41 and a crank angle sensor 42 are connected in addition to the valve lift sensor 10, and a charging voltage detecting section 74 is provided.
Is connected to monitor the capacitor voltage.

Further, an output side of the microcomputer 31 is connected to an engine control unit (not shown). The starter motor energization signal for permitting the starter motor to be energized is connected to the engine control unit. The control of No. 1 terminates the control at the time of starting and switches to the control at the normal valve timing, and outputs a normal timing valve operation signal for operating the fuel injection and ignition timing at the normal timing.

Incidentally, the ignition switch 40 is turned off.
Since the electromagnetic coils 5 and 6 provided on the electromagnetically driven valve 1 in the state are in a non-energized state, each valve 4
A balanced neutral position between the springs 13 and 19,
That is, as shown in FIG. 1, the valve is at rest in a half-open state.

The starting control of the electromagnetic valve 1 in the electromagnetic valve driving controller 30 is performed according to the flowcharts shown in FIGS.

Hereinafter, the start-time control processing employed in the present embodiment will be described with reference to the timing chart of FIG. 5 according to the start-time control routine of FIG. 3 and the valve suction subroutine of FIG. In the present embodiment, all the valves 4 are sequentially fully opened before starting, and all the valves 4 are sequentially fully closed after starting, so that the limit value of the hold current at that time is learned. Things.

In the starting control routine of FIG. 3, first, in step S1, the ignition switch 40 is referred to,
When the ignition switch 40 is OFF, the routine exits as it is, and the ignition switch 40 is turned ON.
Wait until you do. And the ignition switch 4
When 0 is turned on (time t1), the process proceeds to step S2,
Capacitors 76, 80 of valve opening electromagnetic coil drive circuit 37
Is started, and in step S3, the capacitor voltage is detected.

Then, it is checked whether or not the capacitor voltage has reached a voltage (set voltage) sufficient to suck the valve 4, and if not, the flow returns to step S1. on the other hand,
When the capacitor voltage reaches the set voltage (time t
Step 2) proceeds to step S4, where a valve suction subroutine is executed.

This valve suction subroutine is processed according to the flowchart shown in FIG. Hereinafter, in this valve suction subroutine, first, step S11
Then, a specific valve 4 (for example, an intake valve of a certain cylinder)
The primary over-excitation current and the secondary over-excitation current charged in the capacitors 76 and 80 are supplied to the valve opening electromagnetic coil 5 at a predetermined timing (time t2 to t3).

Then, in step S12, the capacitors 76 and 80 of the valve opening electromagnetic coil drive circuit 37 are recharged in preparation for the next valve suction. Further, in step S13, the output of the valve lift sensor 10 is read, and in step S14,
In S15, the hold state is determined.

In this embodiment, the output value of the valve lift sensor 10 is within 10% of the value initially set as the output value when the valve is fully opened, and the valve lift sensor 10
When the output change within 1% continues within 1%, it is determined that the valve is held, that is, the output value is in the fully opened state of the intake valve 4, and the process proceeds to step S16, where the output value of the valve lift sensor 10 at this time is determined. Is detected, and R
AM (not shown) is stored as a fully open reference value, and the process proceeds to step S17.

In step S17, it is determined whether or not the valve 4 is fully opened for the first time.
Proceed to step 18 to exit the routine for the second and subsequent times.

In step S18, the hold current to be supplied to the valve opening electromagnetic coil 5 is gradually reduced. In step S19, the output of the valve lift sensor 10 is determined by referring to the output value of the valve lift sensor 10. Investigate whether it has changed suddenly.

When the output value of the valve lift sensor 10 changes abruptly (in this embodiment, the change is judged to be abrupt when the rate of change is 5% or more), the process proceeds to step S20, and the hold current at this time is read. Store as the limit value and exit the routine.

After the first valve suction subroutine is completed for one valve 4, the other valves 4
(For example, the exhaust valve of a certain cylinder), the valve suction subroutine described above is executed, and the valve opening electromagnetic coil 5 is opened.
At a predetermined timing, a primary over-excitation current and a secondary over-excitation current are supplied (time t3 to t4), the valve hold state of the valve 4 is determined based on the output value of the valve lift sensor 10, and the valve hold state is determined. Is determined, the output value of the valve lift sensor 10 at this time is
1 is stored as a fully open reference value in a RAM (not shown),
Also, the output value of the hold current is gradually reduced, the output value of the valve lift sensor 10 at that time is read, and the hold current when the output value of the valve lift sensor 10 changes suddenly is read. Learn the limits.

At the time of the second and subsequent full opening operations of the valve 4, since the routine exits from step S17, the hold current stored in step S20 is equal to
The limit value is stored until the ignition switch 40 is turned off.

The hold current is compared with the output value of the valve lift sensor 10 and the fully open reference value, and is continuously output as long as the output value reaches the fully open reference value (time t4 to t5). .

When all the valves 4 are fully opened, the process proceeds to step S5, where charging of the capacitors 76 and 80 of the valve closing electromagnetic coil driving circuit 36 is started.
In step 6, check whether the starter switch is ON.
In step S7, the starter motor is started (time t
4).

Thereafter, in step S8, the crank angle is detected based on the crank angle pulse, and the flow advances to step S9.
At the regular valve timing synchronized with the crank angle, each valve 4 is sequentially fully closed in accordance with the aforementioned valve suction subroutine.

In step S16, the valve hold state is detected, and the output value of the valve lift sensor 10 at this time is set as a fully closed reference value in the RAM of the microcomputer 31.
In step S20, the hold current at the time of the first full-close operation is read, and the limit value of the hold current is learned.

Then, step S of the start-time control routine
Proceed to 10 to output a normal timing valve operation signal to the engine control device, permit fuel injection and ignition, and exit the routine.

As a result, fuel injection and ignition for the fuel injection target cylinder and the ignition target cylinder are sequentially started at regular timing, and the engine is started (time t8, t).
9). Incidentally, the fuel injection and the ignition may be started after all the valves 4 are once closed.

As described above, in the present embodiment, after the ignition switch 40 is turned on, the valve 4 is first turned on.
Once fully open or fully closed, then gradually reduce the hold current maintaining this fully open or fully closed state,
In the meantime, the output value of the valve lift sensor 10 is monitored, and the hold current when the output value of the valve lift sensor 10 changes suddenly is learned as a limit value. And the like, the individual difference in the hold current is corrected, and the hold current can be set to an optimal value, for example, by increasing the limit value by 10%, based on the limit value, thereby reducing power consumption. Can be.

Further, even if the starter switch 41 is turned on after the ignition switch 40 is turned on, the capacitors 76 and 80 provided in the respective electromagnetic coil drive circuits 36 and 37 can be used.
Until the charging of the starter motor is completed, charging of the capacitors 76 and 8 is prohibited.
The charging to 0 can be sufficiently performed, and the valve 4 can be reliably sucked.

Further, the first valve fully opened after the ignition switch is turned ON and the hold state when the valve is fully closed are detected, and the output value of the valve lift sensor 10 at that time is learned as a fully open reference value and a fully closed reference value. As a result, individual differences in the valve lift sensor 10 and fluctuations in the output value due to aging are corrected, the fully open position and the fully closed position of the valve 4 can be accurately detected, and the control accuracy of the subsequent valve timing is improved. I do.

FIG. 6 shows a starting control routine according to the second embodiment of the present invention. In the present embodiment, before the cranking starts, all valves 4 are once fully closed, then fully opened, and then the starter motor is started.

That is, in the starting control routine shown in FIG. 6, the signal of the ignition switch is read in step S21, and when it is ON, the process proceeds to step S22 to check whether or not the valve closing operation of all the valves 4 has been completed. Immediately after the ignition switch is turned on, the valves 4 are in the neutral position held by the springs 13 and 19, and the valve closing operation is not completed. Therefore, the process proceeds to step S23, where the valve closing electromagnetic coil drive circuit 36 The charging of the capacitors 76 and 80 is started.

At step S24, the capacitors 76,
It is checked whether or not the capacitor voltage with respect to 80 has reached the set value, and if not, the process returns to step S21, and
If it has reached, the process proceeds to step S25, in which the valve suction subroutine of FIG. 4 described in the first embodiment is executed, and each valve 4 is sequentially fully closed, and the output value of the valve lift sensor 10 at that time is fully output. A process for storing the reference value in the RAM of the microcomputer 31 is performed, and at the first time of the fully closing operation, a limit value of a hold current necessary for maintaining the fully closed state of the valve is learned.

Thereafter, the flow advances to step S26 to start charging the capacitors 76 and 80 of the valve opening electromagnetic coil drive circuit 37. Then, when the capacitor voltage charged in the capacitors 76 and 80 becomes equal to or higher than the set value, the process proceeds from step S27 to step S28, where the above-described valve suction subroutine is executed again, and each valve 4 is sequentially fully opened. Then, the output value of the valve lift sensor 10 at that time is set as the fully open reference value and the R
A process for storing the value in the AM is performed. Further, when the valve fully opening operation is performed for the first time, a limit value of a hold current necessary for maintaining the valve 4 in the fully open state is learned.

When the full opening operation of all the valves 4 is completed, the process proceeds to step S29, where the two electromagnetic coil driving circuits 3
The 6, 76 capacitors 76, 80 are recharged in preparation for the next discharge. Thereafter, it is checked in step S6 whether or not the starter switch is ON. If the switch is ON, the starter motor is started and the engine is started in step S7.

Next, in step S8, the crank angle is detected based on the crank angle pulse, and in step S9, each valve 4 is synchronized with the normal valve timing synchronized with the crank angle.
Are successively fully closed, and the routine proceeds to step S10, where a normal timing valve operation signal is output to the engine control device, fuel injection and ignition are permitted, and the routine exits.

As described above, in the present embodiment, all the valves 4 are fully closed and fully opened before the start of cranking, and the valves 4 are fully closed and fully opened irrespective of the activation of the starter motor. Therefore, the output of the valve lift sensor 10 can be detected without being affected by noise or the like, and the output value of the valve lift sensor 10 can be detected as a parameter. Current and the like can be accurately detected.

Further, at the start of the start of the starter motor, since all the valves 4 are fully opened, there is no compression or expansion by the piston 46 at the initial stage of the start, and the engine can be started with a small force.

FIG. 7 shows a starting control routine according to a third embodiment of the present invention. This embodiment is the reverse of the second embodiment described above, in which, before starting cranking, all valves 4 are once fully opened and then fully closed, and then the starter motor is started. The valve is designed to open the valves sequentially at regular valve timing.

That is, in the starting control routine shown in FIG. 7, the signal of the ignition switch is read in step S31, and if it is ON, the process proceeds to step S32 to check whether or not the valve opening operation of all the valves 4 has been completed. Immediately after the ignition switch is turned on, the valves 4 are in the neutral position held by the springs 13 and 19, and the valve opening operation has not been completed. Therefore, the process proceeds to step S33, where the valve closing electromagnetic coil drive circuit 36 The charging of the capacitors 76 and 80 is started.

Next, in step S34, it is checked whether or not the capacitor voltage for the capacitors 76 and 80 has reached the set value. If not, the process returns to step S31. If it has reached, the process proceeds to step S35. The valve suction subroutine of FIG. 4 described in the first embodiment is executed, and each valve 4 is sequentially fully opened, and the output value of the valve lift sensor 10 at that time is stored in the RAM of the microcomputer 31 as a fully opened reference value. The process is further performed, and at the time of the first full-opening operation, the limit value of the hold current necessary for maintaining the fully open state of the valve 4 is learned.

Thereafter, the flow advances to step S36 to start charging the capacitors 76 and 80 of the valve closing electromagnetic coil drive circuit 36. Then, when the capacitor voltage charged in the capacitors 76 and 80 becomes equal to or higher than the set value, the process proceeds from step S37 to step S38, where the above-described valve suction subroutine is executed again, and each valve 4 is sequentially fully closed. Then, the output value of the valve lift sensor 10 at that time is set as the fully closed reference value and R
The process of storing the value in the AM is performed, and when the valve fully closing operation is performed for the first time, the limit value of the hold current necessary to maintain the valve 4 in the fully closed state is learned.

When the full closing operation of all the valves 4 is completed, the process proceeds to step S39, where the two electromagnetic coil driving circuits 3
The 6, 76 capacitors 76, 80 are recharged in preparation for the next discharge. Subsequent steps are the same as those in the flowchart shown in FIG. 6 of the second embodiment, and a description thereof will be omitted.

As described above, in this embodiment, since all the valves 4 are temporarily closed before starting the cranking, the intake stroke can be started immediately by fully opening the valves at the time of the cranking. The engine can be started early.

The present invention is not limited to each of the above embodiments. For example, the hold current may be directly detected by a current sensor.

[0071]

As described above, according to the present invention,
When the engine is started, the hold current for maintaining the intake and exhaust valves fully closed or fully open is gradually reduced to learn the limit value of the hold current that cannot maintain the intake and exhaust valves fully closed or fully open. However, since the actual hold current is set based on this limit value, power consumption is reduced, and the optimum hold current must always be set in response to manufacturing variations in valve train systems, aging, etc. Can be.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an electromagnetic valve drive control device according to a first embodiment.

FIG. 2 is a configuration diagram of the same driving circuit.

FIG. 3 is a flowchart showing a start-time control routine;

FIG. 4 is a flowchart showing a valve suction subroutine of the same.

FIG. 5 is a timing chart showing an operation state of each operation unit.

FIG. 6 is a flowchart showing a start-time control routine according to a second embodiment;

FIG. 7 is a flowchart showing a start-time control routine according to a third embodiment;

[Explanation of symbols]

 4: Intake / exhaust valve 10: Valve lift sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G05B 11/36 G05B 11/36 P 13/02 13/02 L

Claims (3)

[Claims] An electromagnetically driven valve for controlling an intake / exhaust valve interposed in an intake / exhaust port of an engine by an electromagnetic coil, wherein a valve lift sensor is provided in addition to the intake / exhaust valve, and the intake / exhaust valve is fully closed or fully opened. A control device for an electromagnetically driven valve, characterized in that the hold current when in the state is gradually lowered and the hold current when the output value of the valve lift sensor suddenly changes is learned as a limit value. 2. The control device for an electromagnetically driven valve according to claim 1, wherein the learning of the hold current is performed before starting the engine. 3. The control device for an electromagnetically driven valve according to claim 1, wherein after the engine is started, the hold current is adjusted based on the learned limit value.