JP2000073791A - Control device for electromagnetic driving valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reconcile the power saving and the seating sound reduction of an electromagnetic driving valve, as to the control device for the electromagnetic driving valve which drives to switch a valve element functioning as the intake valve or the exhaust valve of an internal combustion engine. SOLUTION: An electromagnetic driving valve 78 has an armature 92 connected to an intake valve 40, and an upper coil 98 and a lower coil 100 to operate the electromagnetic force to the armature 92, and the intake valve 40 is driven to open and close by producing a specific pattern of instruction current to the coils. In the low load rotating operation time of the internal combustion engine, an instruction current of a low seating speed pattern is used. By this pattern, the instruction current is risen to an attraction current in a rapid timing. In order to reduce the seating speed of the armature 92, the electromagnetic force is regulated by mainly the attraction current and the attraction period. In the high load operation time, an operation stabilizing pattern to increase the attraction current in the low seating speed pattern in used.

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, and more particularly to a control device for an electromagnetically driven valve suitable for controlling an electromagnetically driven valve for opening and closing an intake valve or an exhaust valve of an internal combustion engine. About.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. Hei 9-19573.
As disclosed in No. 6, an electromagnetically driven valve is known. The conventional electromagnetically driven valve includes a valve body functioning as an intake valve or an exhaust valve of an internal combustion engine, and an armature connected to the valve body. The valve body and the armature can be displaced in the axial direction of the valve body. A first electromagnet and an upper spring are disposed above the armature. A second electromagnet and a lower spring are provided below the armature. The armature is held at a neutral position between the first electromagnet and the second electromagnet by an upper spring and a lower spring. Each of the first electromagnet and the second electromagnet generates an electromagnetic force for attracting the armature when an exciting current is supplied. Therefore, according to the above-mentioned conventional electromagnetically driven valve, the valve body is opened and closed at an appropriate timing by making the electromagnetic force generated by the first electromagnet and the second electromagnet cooperate with the spring force generated by the upper spring and the lower spring. Can be driven.

[0003]

In the above-mentioned conventional electromagnetically driven valve, the waveform of the exciting current supplied to the electromagnet for displacing the valve body from one displacement end to the other displacement end is such that the valve body has a displacement end. The current pattern is set so as to decrease immediately before reaching. According to this current pattern, the electromagnetic force acting on the armature when the armature is seated on the electromagnet is reduced, so that the seating sound generated at the time of seating is reduced.

On the other hand, for a constant exciting current supplied to the electromagnet, the electromagnetic force acting between the electromagnet and the armature increases as the distance between them decreases. Therefore,
From the viewpoint of saving power of the electromagnetically driven valve, it is necessary to start energizing the electromagnet when the distance between the electromagnet and the armature is as small as possible, that is, when the valve element approaches the displacement end. It is valid.

However, when energization is started at the above timing, the ratio of the change in the electromagnetic force to the change in the exciting current increases, so that the minimum unit of the electromagnetic force that can be adjusted based on the exciting current increases. For this reason, if the valve body is to be surely displaced to the displacement end, the electromagnetic force actually obtained becomes excessive with respect to the required electromagnetic force. As a result, the speed at which the armature is seated on the electromagnet increases, and a large seating sound is generated. As described above, according to the conventional electromagnetically driven valve, it is difficult to achieve both excellent quietness and excellent power saving characteristics.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to reduce power consumption of an electromagnetically driven valve and reduce seating noise of the electromagnetically driven valve in a situation where quietness is required. It is an object of the present invention to provide a control device for an electromagnetically driven valve that is possible.

[0007]

The above object is achieved by the present invention.
As described in, comprises a valve body that functions as an intake valve or an exhaust valve of an internal combustion engine, an armature connected to the valve body, and an electromagnet that applies an electromagnetic force to the armature, and includes an electromagnetic force and a spring force. An electromagnetically driven valve control device that opens and closes the valve body by causing the valve body to open and close, the operating state detecting means detecting an engine operating state, and displacing the valve body from one displacement end to the other displacement end. Energization control means for controlling the energization of the electromagnet, the energization control means of the electromagnetically driven valve for setting the start of energization to the electromagnet with respect to the displacement of the valve body according to the engine operating state Achieved by the controller.

According to the first aspect of the present invention, the electromagnetic force acting on the armature for a constant exciting current supplied to the electromagnet changes according to the distance between the armature and the electromagnet. Therefore, in the process where the valve body is displaced from one displacement end to the other displacement end, if the energization time to the electromagnet changes with respect to the displacement of the valve body, the magnitude of the electromagnetic force generated for a certain excitation current Changes. In this case, the ratio of the change of the electromagnetic force to the change of the exciting current, that is, the minimum unit of the electromagnetic force that can be adjusted by the exciting current also changes. The energization control means sets the timing for starting energization of the electromagnet with respect to the displacement of the valve body according to the engine operating state. For this reason, a state in which a large electromagnetic force can be generated with respect to a constant excitation current and a state in which the minimum unit of the electromagnetic force that can be adjusted based on the excitation current is small, depending on the engine operating state. In a state where a large electromagnetic force is generated with respect to a constant exciting current, power saving of the electromagnetically driven valve is achieved. When the minimum unit of the electromagnetic force that can be adjusted based on the exciting current is small, the electromagnetic force acting on the armature may be adjusted so that the speed at which the armature sits on the electromagnet (seating speed) is reduced. It will be easier. Therefore, according to the present invention, it is possible to realize a state where power saving is achieved and a state where the seating speed is reduced according to the engine operating state.

Further, the above object is achieved by a control device for an electromagnetically driven valve according to claim 1.
The energization control means is achieved by a control device for an electromagnetically driven valve that makes the energization start timing of the electromagnet earlier when the engine operation state is in a low-load low-rotation region than in a normal operation region.

According to the second aspect of the present invention, the energization control means advances the energization start timing to the electromagnet when the engine operating state is in the low-load low-rotation range as compared with the normal operation range. That is, the energization control unit starts energization in a low-load low-rotation region in a state where the distance between the armature and the electromagnet is large. In this case, since the ratio of the change of the electromagnetic force to the change of the exciting current becomes small, the electromagnetic force can be adjusted with high resolution, and as a result, the seating speed can be reduced. In the low-load and low-speed range, the operating noise of the internal combustion engine is low, so the quietness of the electromagnetically driven valve is required. Therefore, according to the present invention, the seating noise can be reduced in a situation where quietness of the electromagnetically driven valve is required.

Further, as described in claim 3, claim 1
Or in the control device of the electromagnetically driven valve according to 2, the energization control means, when the engine operating state is in a high load region, than when in the normal operation region, earlier the start of energization to the electromagnet, Moreover, according to the control device for the electromagnetically driven valve that increases the amount of energization, the operation stability of the electromagnetically driven valve during high-load operation can be ensured.

According to the third aspect of the present invention, the energization control means advances the energization start timing to the electromagnet earlier when the engine operation state is in a high load range than in a normal operation range, and Increase the amount of electricity. Therefore, in a high load region, a large kinetic energy is applied to the armature. As a result, the kinetic energy of the valve element due to the high in-cylinder pressure in the high load region is compensated for, and the valve element can be reliably displaced to the displacement end.

[0013]

FIG. 1 is an overall configuration diagram of an internal combustion engine equipped with an electromagnetically driven valve control device according to an embodiment of the present invention. The internal combustion engine is controlled by the engine ECU 10. The internal combustion engine has an intake port 12. Inlet 1
2, an air cleaner 14 is provided. A surge tank 20 is connected to the intake port 12 via a throttle body 18.

A throttle valve 22 is provided inside the throttle body 18. In the vicinity of the throttle valve 22, a throttle opening sensor 24 is provided. The throttle opening sensor 24 outputs an electric signal corresponding to the opening of the throttle valve 22 (hereinafter, referred to as a throttle opening TA) to the engine ECU 10. The surge tank 20 is provided with an intake pressure sensor 26. The intake pressure sensor 26 outputs an electric signal corresponding to the internal pressure of the surge tank 20, that is, the intake pipe negative pressure PM, to the engine ECU 10. An intake port 28 of each cylinder communicates with the surge tank 20. The air that has flowed into the surge tank 20 is supplied to the internal combustion engine via the intake port 28 of each cylinder. A fuel injection valve 36 is provided at the intake port 28 of each cylinder. The fuel injection valve 36 is an engine EC
Intake port 28 according to the drive signal supplied from U10
Inject fuel into

The internal combustion engine has a cylinder block 42. Inside the cylinder block 42, a combustion chamber 44
Are formed. The combustion chamber 44 communicates with the intake port 28 via the intake valve 40. The intake valve 40 is electrically connected or disconnected between the intake port 28 and the combustion chamber 44 by being opened and closed. The internal combustion engine has a piston 4
6 is provided. A crankshaft 48 is connected to the piston 46. The crankshaft 48 rotates when the piston 46 slides up and down in the cylinder 42. A crank angle sensor 50 is provided on the crank shaft 48. The crank angle sensor 50 outputs a pulse signal to the engine ECU 10 every time the crank shaft 48 rotates by a predetermined rotation angle. The engine ECU 10 detects the crank angle and the engine speed NE of the internal combustion engine based on the output signal of the crank angle sensor 50.

An ignition plug 52 is provided in the combustion chamber 44. The air-fuel mixture sucked into the combustion chamber 44 is ignited by an ignition plug 52. The combustion chamber 44 is provided with an in-cylinder pressure sensor 54. The in-cylinder pressure sensor 54
An electric signal corresponding to the pressure in the combustion chamber 44, that is, the in-cylinder pressure is output to the engine ECU 10. Further, a cooling water passage 56 is provided in the cylinder block 42 so as to surround the combustion chamber 44.

An exhaust manifold 62 is connected to the combustion chamber 44 via an exhaust valve 60. An exhaust port 66 is formed in the exhaust manifold 62. Exhaust valve 6
A value of 0 sets the combustion chamber 44 and the exhaust port 66 to be in a conducting or blocking state by being driven to open and close. Downstream of the exhaust manifold 62, a catalytic converter 70 is provided. The exhaust gas discharged from the internal combustion engine is purified by the catalytic converter 70 and then discharged from the exhaust port 72 into the atmosphere.

In the system of this embodiment, the intake valve 40
The exhaust valve 60 is opened and closed by electromagnetically driven valves 78 and 80, respectively. FIG. 2 is a sectional view of an electromagnetically driven valve 78 that drives the intake valve 40 to open and close. The electromagnetically driven valve 80
Are electromagnetically driven valves 7 except that the exhaust valve 60 is opened and closed.
8 has the same configuration as that of FIG. Therefore, in the following description, the structure and operation of the electromagnetically driven valve 78 will be described as a representative example thereof.

The electromagnetically driven valve 78 includes the intake valve 40 described above. The intake valve 40 is a member disposed in the cylinder head 82, and has a lower end in the figure at the combustion chamber 4 of the internal combustion engine.
4 is exposed. The above-described intake port 28 is provided in the cylinder head 82. Intake port 28
Is provided with a valve seat 86 for the intake valve 40.
When the intake valve 40 is separated from the valve seat 86, the intake port 28 and the combustion chamber 44 are brought into conduction, and when the intake valve 40 is seated on the valve seat 86, the intake port 28 and the combustion chamber 44 are shut off.

A valve shaft 88 is fixed to the intake valve 40. The valve shaft 88 is held by a valve guide 90 so as to be slidable in the axial direction. An armature 92 is fixed to an upper portion of the valve shaft 88. The armature 92 is, for example,
An annular member made of a soft magnetic material. Above the armature 92, an upper core 94 is provided. Further, a lower core 96 is provided below the armature. The upper core 94 and the lower core 96 are both members made of a magnetic material. The upper core 94 holds the upper coil 98, and the lower core 96 holds the lower coil 100. An outer cylinder 102 is provided on the outer periphery of the upper core 94 and the lower core 96. The outer cylinder 102 holds the upper core 94 and the lower core 96 such that a predetermined space is secured between them.

The valve shaft 88 is elastically supported in the axial direction by an upper spring 104 and a lower spring 106. The upper spring 104 and the lower spring 106 are arranged such that a neutral position of the armature 92 is
It is adjusted to be at an intermediate position between the lower core 4 and the lower core 96. The engine ECU 10 is connected to the upper coil 98 and the lower coil 100 of the electromagnetically driven valve 78. The engine ECU 10 controls the excitation current supplied to the upper coil 98 and the lower coil 100 to drive the intake valve 40 to open and close appropriately.

Next, the operation of the electromagnetically driven valve 78 will be described. In the electromagnetically driven valve 78, a magnetic flux can be generated by the upper coil 98 by supplying an exciting current to the upper coil 98. The magnetic flux generated by the upper coil 98 flows through a path including the upper core 94 and the armature 92. At this time, the armature 92 is placed between the armature 92 and the upper core 94.
An electromagnetic force is generated in the direction of suction to 4.

Therefore, according to the electromagnetically driven valve 78, the armature 92, the valve shaft 88, and the intake valve 40 can be displaced toward the upper core 94 by supplying an exciting current to the upper coil 98. The valve shaft 88 is provided with the armature 9
2 can be displaced toward the upper core 94 until the seat 2 is seated on the upper core 94. The intake valve 40 has an armature 92
When the airbag is seated on the upper core 94, the intake port 28
Close. Therefore, according to the electromagnetically driven valve 78, by supplying the exciting current to the upper coil 98, the intake valve 40 can be fully closed. Hereinafter, the position of the intake valve 40 in the fully closed state is referred to as a closed end of the intake valve 40.

When the intake valve 40 is maintained at the closed end, the upper spring 104 and the lower spring 106
Biases the valve shaft 88 toward the neutral position. When the supply of the exciting current to the upper coil 98 is stopped in such a situation, the valve shaft 88 starts a single-oscillation motion according to the spring force of the upper spring 104 and the lower spring 106. When the valve shaft 88 is displaced in the valve opening direction, the sliding resistance between the valve shaft 88 and the valve guide 90 and the combustion chamber 44
In the cylinder acts in a direction that hinders the movement of the valve shaft 88.
For this reason, the kinetic energy of the valve shaft 88 due to the simple vibration motion gradually decreases as the displacement of the valve shaft 88 progresses.

According to the electromagnetically driven valve 78, the lower coil 10
By supplying an exciting current to 0, a magnetic flux can be generated by the lower coil 100. The magnetic flux generated by the lower coil 100 flows through a path including the lower core 96 and the armature 92. At this time, an electromagnetic force is generated between the armature 92 and the lower core 96 so as to attract the armature 92 to the lower core 96. Therefore, according to the electromagnetically driven valve 78, the excitation current is supplied to the lower coil 100 to compensate for the above-mentioned kinetic energy attenuation due to the sliding resistance and the in-cylinder pressure, and the valve is driven until the armature 92 is seated on the lower core 96. The shaft 88 can be displaced.

The intake valve 40 is fully opened when the armature 92 is seated on the lower core 96. The position of the intake valve 40 in the fully open state is hereinafter referred to as the open end of the intake valve 40. Therefore, according to the electromagnetically driven valve 78, the upper coil 9
By stopping the supply of the excitation current to the lower coil 8 and starting the supply of the excitation current to the lower coil 100 at a predetermined timing, the intake valve 40 can be displaced from the valve-closed end to the valve-opened end. Hereinafter, when the valve-closing end and the valve-opening end of the intake valve 40 are collectively referred to as a displacement end.

When the supply of the exciting current to the lower coil 100 is stopped after the intake valve 40 reaches the valve opening end, the intake valve 4
0 starts displacement toward the valve closing end according to the operation of the simple vibration. When the intake valve 40 is displaced toward the valve closing end, the kinetic energy of the intake valve 40 is attenuated due to the sliding resistance between the valve shaft 88 and the valve guide 90. Also in this case, as in the case of displacing toward the valve opening end, by starting the supply of the exciting current to the upper coil 98 at an appropriate timing, the kinetic energy due to the sliding resistance is compensated, and
The valve shaft 88 can be displaced until the armature 92 is seated on the upper core 94. Thereafter, by supplying an exciting current repeatedly to the upper coil 98 and the lower coil 100 at an appropriate timing, the intake valve 40 can be opened and closed between the valve closing end and the valve opening end.

Similarly, with respect to the electromagnetically driven valve 80, the exhaust valve 60 can be opened and closed between the valve closing end and the valve opening end by repeatedly supplying an exciting current to the upper coil 98 and the lower coil 100. In the following description, when the intake valve 40 and the exhaust valve 60 are collectively referred to,
It will be referred to as valve bodies 40 and 60. The electromagnetic force F acting between the armature 92 and the upper core 94 is expressed by the following equation, where I is an exciting current supplied to the upper coil 98, and x is a gap between the armature 92 and the upper core 94.

F = α · I ² / (x + β) ² (1) where α and β are constants determined by the characteristics of the upper core 94 and the like. From the above equation (1), the electromagnetic force F is proportional to the square of the exciting current I supplied to the upper coil 98,
Further, it can be seen that it is substantially inversely proportional to the square of the gap x between the armature 92 and the upper core 94. Similarly, the electromagnetic force acting between the armature 92 and the lower core 96 is proportional to the square of the exciting current supplied to the lower coil 100, and is substantially inversely proportional to the square of the gap between the armature 92 and the lower core 96. . Therefore, in order to operate the electromagnetically driven valves 78 and 80 with a small exciting current, that is, to achieve power saving of the electromagnetically driven valves 78 and 80, the armature 92 is provided with the upper core 94 or the lower core 96.
It is advantageous to start energizing the upper coil 98 or the lower coil 100 at a point sufficiently close to.

FIG. 3 shows the electromagnetically driven valve 7 from the above viewpoint.
Lower coil 10 suitable for power saving of 8, 80
7 shows a waveform of a command current with respect to 0. In FIG.
(A) shows the displacement of the valve bodies 40 and 60 from the valve closing end to the valve opening end, and (B) shows the waveform of the command current to the lower coil 100. The waveform of the exciting current shown in FIG.
Hereinafter, it is referred to as a “power saving pattern”.

As shown in FIG. 3, in the power saving pattern, the command current for the lower coil 100 is
At a predetermined time when the valve 60 has moved beyond the neutral position and approached the valve opening end, it is raised from "0" to the suction current I1. Hereinafter, a period during which the command current is maintained at “0” in FIG. 3B is referred to as an off period t1. After the off period t1, the command current is maintained at the attraction current I1 only during the attraction period t2. The suction period t2 is set so that the end time is immediately before the valve bodies 40 and 60 reach the valve-open end. Suction period t2
Thereafter, the value of the command current is reduced from the attraction current I1 to the holding current I2 over the reduction period t3. Then, after the end of the decrease period t3, the command current is maintained at the holding current I2 until a request to close the valve bodies 40 and 60 occurs.

According to the above power saving pattern, the valve element 4
The supply of the attraction current I1 is started at the time when 0 and 60 approach the valve-open end, so that the valve elements 40 and 60 are driven to the valve-open end using the relatively small attraction current I1. An electromagnetic force can be applied to the armature 92. Therefore, according to the command current of the power saving pattern, the electromagnetically driven valve 7
8, 80 power savings can be achieved.

The inductance of the lower coil 100 increases as the gap between the armature 92 and the lower core 96 becomes smaller. Therefore, as described above,
When the command current rises to the attraction current I1 when the valve bodies 40 and 60 approach the valve-opening ends, the actual excitation current (actual current) supplied to the lower coil 100 is delayed due to the influence of inductance. Stand up. Therefore, the time when the command current rises to the attraction current I1, that is, the end time of the off-period t1 is within a range in which the valve bodies 40 and 60 can be displaced to the valve-opening end in consideration of the delay of the rise of the actual current. It is necessary to set so that the timing is late.

In the above description, the valve body 40,
Although the case where the valve 60 is displaced from the valve-closed end toward the valve-opened end has been described, the case where the valve bodies 40 and 60 are displaced from the valve-opened end toward the valve-closed end is also described with reference to FIG. By using the command current of the power saving pattern shown in B), the power saving of the electromagnetically driven valves 78 and 80 can be achieved.

When the electromagnetically driven valves 78, 80 open and close, the seating sound when the armature 92 is seated on the upper core 94 or the lower core 96, and the valve bodies 40, 60
A seating sound when the user sits on the valve seat 86 (hereinafter, these operating sounds are referred to as seating sounds of the electromagnetically driven valves 78 and 80) is generated. For this reason, as in the case where the internal combustion engine is operating in a low load / low rotation range (for example, in an idling state),
When the operating noise of the internal combustion engine is low, the electromagnetically driven valve 7
In order to increase the quietness of the 8, 80, it is desirable to reduce the sitting sound. In order to reduce the seating noise of the electromagnetically driven valves 78 and 80, the electromagnetic force acting on the armature 92 is adjusted so that the displacement speed (seating speed) when the valve bodies 40 and 60 reach the displacement ends is reduced. is necessary.

However, according to the command current of the above-described power saving pattern, the command of the attracting current I1 is started when the armature 92 approaches the upper core 94 or the lower core 96, so that a large value for the small attracting current I1. Electromagnetic force is generated. Therefore, even if the value of the attraction current I1 is slightly changed, the electromagnetic force acting on the armature 92 is greatly changed. Therefore, when using the command current of the power saving pattern, it is difficult to adjust the electromagnetic force with high accuracy based on the waveform of the command current.

As described above, as the gap between the armature 92 and the upper core 94 or the lower core 96 increases, the electromagnetic force acting on the armature 92 decreases. Therefore, if the command current is raised to the attraction current I1 at an early timing, the electromagnetic force generated by the constant attraction current I1 decreases. In this case, although the energy efficiency is reduced, the ratio of the change in the electromagnetic force acting on the armature 92 to the change in the attraction current I1 and the attraction period t2 is reduced, so that the magnitude of the electromagnetic force is increased based on the excitation current. It is possible to adjust with the resolution.

FIG. 4 shows the electromagnetically driven valve 7 from the above viewpoint.
Lower coil 1 suitable for reducing sitting sound of 8, 80
5 shows a waveform of a command current for 00. In FIG.
(A) shows the displacement of the valve bodies 40 and 60 from the valve closing end to the valve opening end, and (B) shows the waveform pattern of the command current to the lower coil 100. The waveform of the exciting current shown in FIG. 4B is hereinafter referred to as a “low seating speed pattern”.

As shown in FIG. 4B, in the low seating speed pattern, the command current is earlier than in the power saving pattern (in the illustrated case, the predetermined current before the valve bodies 40 and 60 reach the neutral position). ), The voltage rises from "0" to the attraction current I1. The command current is the suction current I1 during the suction period t2.
After that, the current is changed to the second attraction current I2, and thereafter, is maintained at the second attraction current I3 for the second attraction period t4. The end of the second suction period t4 is almost equal to the valve body 4
0 and 60 are set so as to coincide with the timing of reaching the valve opening end. After the second attraction period t4, the value of the command current is reduced from the second attraction current I3 to the holding current I2 over the reduction period t3. Then, after the end of the decrease period t3, the command current is maintained at the holding current I2 until a request to close the valve bodies 40 and 60 occurs.

As described above, in the low seating speed pattern, the command current rises to the attraction current I1 earlier than in the power saving pattern. Therefore, the electromagnetic force acting on the armature 92 is small with respect to the constant attracting current I1. Therefore, according to the command current of the low seating speed pattern, the electromagnetic force acting on the armature 92 can be adjusted with high resolution by changing the values of the attraction current I1 and the attraction period t2.
2 can reduce the seating speed.

Further, the greater the distance between the armature 92 and the lower core 96, the smaller the inductance of the lower coil 100. Therefore, in the low seating speed pattern, the command current for the lower coil 100 rises from "0" to the attraction current I1 in a state where the inductance of the lower coil 100 is small. Lower coil 1
In the state where the inductance of 00 is small, the actual current follows the change in the command current with high responsiveness. Therefore, according to the command current of the low seating speed pattern, the lower coil 10
The actual current of 0 can be controlled with high accuracy. The electromagnetic force acting between the armature 92 and the lower core 96 has a magnitude corresponding to the actual current of the lower coil 100. Therefore,
With the command current of the low seating speed pattern, the electromagnetic force acting on the armature 92 can be adjusted with high resolution by controlling the actual current of the lower coil 100 with high accuracy.

In the above description, the valve element 40,
Although the case where the valve 60 is displaced from the valve-closed end toward the valve-opened end has been described, the case where the valve bodies 40 and 60 are displaced from the valve-opened end toward the valve-closed end is also described with reference to FIG. By using the command current of the low seating speed emphasizing pattern shown in B), the seating noise of the electromagnetically driven valves 78 and 80 can be reduced.

When the internal combustion engine is operating under a high load, a high cylinder pressure is generated. As described above, when the valve bodies 40 and 60 are displaced from the valve-closing end to the valve-opening end, the in-cylinder pressure acts in a direction that impedes the displacement. Therefore, when the in-cylinder pressure is high, the amount of kinetic energy attenuation of the valve bodies 40 and 60 increases. Even in such a case, it is necessary to apply a sufficiently large electromagnetic force to the armature 92 in order to surely displace the valve bodies 40 and 60 to the valve opening ends. On the other hand, when the in-cylinder pressure is high, that is, when the internal combustion engine is operating under a high load state, the internal combustion engine generates a loud operating noise. The need to reduce is small.

FIG. 5 shows a waveform of a command current to the lower coil 100 which is preferable when the internal combustion engine is operating under a high load state from the above viewpoint. In FIG. 5, (A) shows the displacement of the valve bodies 40 and 60 from the valve closing end to the valve opening end.
(B) shows the waveform pattern of the command current to the lower coil 100 of the electromagnetically driven valves 48 and 80. FIG. 5B
The excitation current waveform shown in
Called.

As shown in FIG. 5B, in the operation stabilization pattern, similarly to the low seating speed pattern, the command current is drawn from "0" at a predetermined time before the valve bodies 40, 60 reach the neutral position. The current is raised to I1. However,
The attraction current I1 is larger than the attraction current I1 in the power saving pattern and the low seating speed pattern (ie,
The value is set to a value large enough to displace the valve bodies 40 and 60 to the valve opening end against the high in-cylinder pressure). After the command current is maintained at the suction current I1 during the suction period t2, the second
The current is changed to the attraction current I3, and thereafter, is maintained at the second attraction current I3 for the second attraction period t4. The second suction period t4 is set so that the end thereof substantially coincides with the timing when the valve bodies 40 and 60 reach the valve opening ends. After the second suction period t4, the value of the command current becomes
The current is reduced from the second attraction current I3 to the holding current I2. After the end of the decrease period t3, the command current is changed to the valve body 40,
The holding current I2 is maintained until a valve closing request of 60 occurs.

When the in-cylinder pressure is high, the valve bodies 40, 6
As the displacement speed of 0 decreases, the time required for the valve bodies 40 and 60 to displace from the valve-closed end to the valve-opened end increases.
Therefore, the suction period t2 and the second suction period t4 are longer than those of the power saving pattern and the low sitting speed pattern. Therefore, in the operation stable pattern, the lower coil 10
The overall amount of power to zero is increased, thereby imparting a large kinetic energy to the armature 92.

As described above, in the operation stable pattern, a large kinetic energy can be applied to the armature 92 by the command current rising to the large attraction current I1 at an early stage. Therefore, according to the command current of the operation stabilization pattern, even when the kinetic energy of the valve elements 40, 60 is greatly attenuated by the high in-cylinder pressure, the attenuation is compensated for and the valve elements 40, 60 are securely moved to the valve-opening end. Can be displaced. As described with respect to the low seating speed pattern, when the command current is started early, the actual current starts quickly because the inductance of the coil is small. Therefore, in the operation stable pattern, the kinetic energy applied to the armature 92 is also increased by realizing the real current that follows the command current with high responsiveness.

As described above, the electromagnetically driven valve 78,
In order to achieve the power saving of 80, it is effective to use the command current of the power saving pattern shown in FIG. However, according to the command current of the power saving pattern, the electromagnetically driven valve 7
It is difficult to reduce the sitting sounds of 8, 80. For this reason, in a situation where quietness of the electromagnetically driven valves 78 and 80 is required, such as when the internal combustion engine is operated at a low load and a low speed, FIG.
It is desirable to use the command current of the low seating speed pattern shown in FIG. Further, during high load operation of the internal combustion engine, it is desirable to use the command current of the operation stabilization pattern shown in FIG. 5B in order to surely displace the valve bodies 40 and 60 to the valve-opening ends when the valves are opened.

The system according to the present embodiment uses the above three types of command currents appropriately in accordance with the operating state of the internal combustion engine and uses them to reduce the power consumption of the electromagnetically driven valves 78 and 80 and reduce the sitting noise. And the fact that the electromagnetically driven valves 78 and 80 can reliably operate during a high-load operation. The above-described function of this embodiment is provided by the engine E
This is realized by the CU 10 executing a predetermined routine. The engine ECU 10 stores, in its internal memory, seven parameters that define the three patterns, namely, the off period t1, the suction period t2, the decreasing period t3, and the second parameter.
The values of the attraction period t4, the attraction current I1, the holding current I2, and the second attraction current I3 are stored as a map corresponding to each operating state of the internal combustion engine. Hereinafter, this map is referred to as a command current map.

The specific values of the parameters corresponding to each pattern are experimentally adapted in advance so as to obtain optimum performance corresponding to each pattern. For example, in the power saving pattern, the off period t1 is long so that the power consumption is reduced and the suction current I1 is small so that the power consumption can be reduced within a range in which the valve bodies 40 and 60 can be displaced to the displacement ends. In the power saving pattern, the second suction period I4 is set to zero. In the low seating speed pattern, the electromagnetically driven valve 7
In particular, the values of the attraction period t2 and the attraction current I1 are mainly adjusted so that the sitting sound generated at 8, 80 is as small as possible. Further, in the operation stabilization pattern, each parameter is adapted so that the valve bodies 40 and 60 can be reliably displaced to the displacement ends even when the internal combustion engine is at the maximum load. Therefore, for example, in the low seating speed pattern and the operation stable pattern shown in FIGS. 4B and 5B, the second attraction current I3
Is smaller than the attraction current I1, but I1 and I3
The magnitude relationship is not limited to this. Similarly, the start and end of the second suction period t4 are not limited to the illustrated timing.

The engine ECU 10 generates a command current in a pattern adapted to the operation state of the internal combustion engine by referring to the command current map according to the operation state of the internal combustion engine. FIG. 6 is a flowchart illustrating a routine that the engine ECU 10 executes to generate a command current in the present embodiment. The routine shown in FIG. 6 is started each time a valve opening request or a valve closing request for each of the valve bodies 40 and 60 occurs. When the routine shown in FIG. 6 is started, first, the process of step 200 is executed.

In step 200, the crank angle sensor 5
The engine speed NE is detected based on the 0 output signal. In the following step 202, the load of the internal combustion engine (hereinafter referred to as load)
Engine load L) is detected. As described above, the in-cylinder pressure of the internal combustion engine increases as the load on the internal combustion engine increases. Therefore, in step 202, the engine E
The CU 10 employs the in-cylinder pressure detected by the in-cylinder pressure sensor 54 as the engine load L.

In step 204, the engine speed NE
Is smaller than the predetermined threshold value NE0, and whether the load L is smaller than the predetermined threshold value L0. The threshold values NE0 and L0 are, for example, the electromagnetically driven valves 78, 8
Engine speed NE and engine load L such that the operating noise of the internal combustion engine is reduced to such an extent that quietness of zero is required.
Is set to the upper limit. For example, the engine speed N
The idling rotational speed of the internal combustion engine is used as the threshold value NE0 of E. Therefore, if the determination in step 204 is affirmative, it is determined that the sitting sounds of the electromagnetically driven valves 78 and 80 should be reduced. In this case, in step 206, the parameters corresponding to the low seating speed pattern are read out with reference to the command current map, and thereafter, the lower coil 100 is read in accordance with these parameters.
After the command current having the low seating speed pattern for the upper coil 98 (when the valve is opened) or the upper coil 98 (when the valve is closed) is generated, the current routine ends.

On the other hand, if a negative determination is made in step 204, the process of step 208 is executed next.
In step 208, it is determined whether or not the engine load L is equal to or greater than a threshold value L0. As a result, if L ≧ L0 holds, it is determined that the operation state of the internal combustion engine is in a high load state. In this case, it is next determined in step 210 whether or not the currently occurring request is a valve opening request. As a result, if a valve opening request is generated, it is determined that it is necessary to displace the valve bodies 40 and 60 to the valve opening end against a high in-cylinder pressure. In this case, in step 212, the parameter corresponding to the operation stable pattern is read out with reference to the command current map.
After the command current of the operation stable pattern for the lower coil 100 is generated according to these parameters, the current routine ends.

On the other hand, in step 210, it is determined that it is not necessary to displace the valve bodies 40 and 60 against the in-cylinder pressure if the request that has occurred is not a valve opening request, that is, a valve closing request. You. If L ≧ L0 does not hold in step 208, the internal combustion engine is operating at low load and high speed. In these cases, it is determined that emphasis should be placed on power saving of the electromagnetically driven valves 78 and 80, and then the process of step 214 is executed. In step 214, the parameters corresponding to the power saving pattern are read out with reference to the command current map. Thereafter, the power saving pattern for the lower coil 100 (when the valve is opened) or the upper coil 98 (when the valve is closed) is read in accordance with these parameters. After this command current is generated, the current routine ends.

In the above routine, in the high load operation region, the command current of the operation stable pattern is used only when the valve is opened. However, the command current of the operation stable pattern is used regardless of whether the valve is opened or closed. Is also good. As described above, according to the present embodiment, the low-load high-speed region of the internal combustion engine,
That is, in the normal operation region realized in the general running state of the vehicle, the power saving of the electromagnetically driven valves 78 and 80 can be achieved by using the command current of the power saving pattern. In a low-load low-rotation region where the operating noise of the internal combustion engine is small, the seating noise of the electromagnetically driven valves 78 and 80 can be reduced by using the command current of the low seating speed pattern. Furthermore, in the high load region where the in-cylinder pressure of the internal combustion engine is high,
By using the command current of the operation stable pattern, the valve body 4
0 and 60 can be reliably displaced to the valve opening end.
As described above, according to the system of the present embodiment, when the quietness of the electromagnetically driven valves 78 and 80 is required, the seating sound of the electromagnetically driven valves 78 and 80 is reduced while achieving the excellent low power consumption characteristics of the electromagnetically driven valves 78 and 80. In addition to the reduction, stable operation of the electromagnetically driven valves 78 and 80 during high-load operation can be ensured.

In the above embodiment, the engine E
The CU 10 executes the processing of steps 200 and 202 of the routine shown in FIG. 6, and the operating state detecting means described in the claims executes the processing of steps 204 to 214. Have been realized respectively. By the way, in the above routine, the engine load L and the engine speed NE are respectively divided into two high and low areas by using the threshold values L0 and NE0. However, the present invention is not limited to this, and the engine load L and the engine speed NE are divided into three or more regions using two or more threshold values, respectively, and each is divided into three regions. The parameter of the command current pattern may be changed. For example, the kinetic energy to be applied to the armature 92 increases as the in-cylinder pressure increases. Therefore, in the operation stable pattern, by increasing the attraction current I1 and the attraction period t2 in accordance with the rise of the in-cylinder pressure, the valve bodies 40, 60 are securely displaced to the displacement ends without excessively increasing power consumption. It becomes possible. Similarly, in the power saving pattern, the valve bodies 40, 6
It is considered that the value of the off-period t1 and the value of the attraction current I1 necessary for displacing 0 to the displacement end vary depending on the engine load L and the engine speed NE. Therefore, even in the power saving pattern, more excellent power saving characteristics can be realized by changing the value of each parameter according to the engine load L and the engine speed NE.

In the above embodiment, the in-cylinder pressure is directly detected by the in-cylinder pressure sensor 54 provided in the internal combustion engine, and this in-cylinder pressure is used as the engine load L. However, in a system without an in-cylinder pressure sensor,
The in-cylinder pressure can be estimated based on the intake pipe negative pressure PM, the throttle opening TA, and the engine speed NE. That is, as the intake pipe negative pressure PM becomes higher (as an absolute value) and as the throttle opening increases, a larger amount of air flows into the combustion chamber 44, so that the in-cylinder pressure increases. However, since the responsiveness of the intake pressure sensor 26 is set low in order to eliminate the pulsation of the intake pipe negative pressure PM accompanying the engine rotation, if the in-cylinder pressure changes transiently, the intake pipe negative pressure P
It is not possible to accurately estimate the in-cylinder pressure using only M. Therefore, the cylinder pressure in the steady operation state is estimated from the intake pipe negative pressure PM, and the throttle opening degree TA and the engine speed NE are estimated.
By correcting the transient change in the in-cylinder pressure, the in-cylinder pressure can be accurately estimated.

[0059]

As described above, according to the first aspect of the present invention, a state in which the power of the electromagnetically driven valve is reduced and a state in which the seating noise is reduced are realized according to the engine operating state. be able to. According to the second aspect of the present invention, it is possible to reduce the sitting noise of the electromagnetically driven valve during low-load low-speed operation of the internal combustion engine where quietness of the electromagnetically driven valve is required.

Further, according to the third aspect of the present invention, the electromagnetically driven valve can be operated stably even during high load operation of the internal combustion engine.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an internal combustion engine to which a control device for an electromagnetically driven valve according to an embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view of an electromagnetically driven valve that opens and closes an intake valve and an exhaust valve in the present embodiment.

FIG. 3A is a diagram showing displacement of a valve body from a valve closing end to a valve opening end; FIG. 3B is a diagram showing a command current of a power saving pattern for the lower coil generated to displace the valve element from the valve-closing end to the valve-opening end.

FIG. 4A is a diagram showing displacement of a valve body from a valve closing end to a valve opening end; FIG. 4B is a diagram showing a command current of a low seating speed pattern for the lower coil generated to displace the valve element from the valve-closing end to the valve-opening end.

FIG. 5A is a diagram showing displacement of a valve body from a valve closing end to a valve opening end. FIG. 5B is a diagram illustrating a command current of an operation stabilization pattern for the lower coil generated to displace the valve element from the valve-closing end to the valve-opening end.

FIG. 6 is a flowchart of a routine executed by an engine ECU in the embodiment.

[Explanation of symbols]

 10 Engine ECU 40 Intake valve (valve element) 60 Exhaust valve (valve element) 78, 80 Electromagnetically driven valve

Continued on the front page (72) Inventor Mitsunori Kadowaki 1 Toyota Town, Toyota City, Aichi Prefecture F-term in Toyota Motor Corporation 3G084 BA23 CA03 CA04 DA00 EC03 FA07 FA10 FA11 FA18 FA21 FA33 FA38 3G092 AA01 AA11 DA01 DA02 DA07 DG02 DG09 EA02 EA08 EA13 FA11 FA14 GA05 GA06 HA05Z HA06Z HA11Z HC01Z HE01Z HE03Z

Claims (3)

[Claims] A valve body that functions as an intake valve or an exhaust valve of an internal combustion engine; an armature connected to the valve body; and an electromagnet that applies an electromagnetic force to the armature. A control device for an electromagnetically driven valve that opens and closes the valve element by causing the valve element to open and close, comprising: operating state detecting means for detecting an engine operating state; and displacing the valve element from one displacement end to another displacement end. Energization control means for controlling energization of the electromagnet, wherein the energization control means sets the energization start timing of the electromagnet with respect to the displacement of the valve element according to the engine operating state. Control device for electromagnetically driven valve. 2. The power supply control unit according to claim 1, wherein when the engine operation state is in a low-load low-rotation range, the power supply start timing of the electromagnet is earlier than in a normal operation range. Item 2. The control device for an electromagnetically driven valve according to Item 1. 3. The energization control means, when the engine operation state is in a high load area, makes the energization start time to the electromagnet earlier and increases the energization amount as compared with the case where the engine is in a normal operation area. The control device for an electromagnetically driven valve according to claim 1 or 2, wherein: