JP3763492B2 - Valve operating device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve operating apparatus for an internal combustion engine in which a valve element is electromagnetically driven, and more particularly to an apparatus having a function for detecting a step-out of an engine valve.
[0002]
[Prior art]
2. Description of the Related Art Conventionally known is an electromagnetically driven valve operating apparatus in which an engine valve of an internal combustion engine, that is, an intake valve and / or an exhaust valve is driven using an electromagnet. In such a valve operating device, as a technique for detecting a so-called step-out in which the engine valve does not operate normally in response to the drive signal supplied to the electromagnet, the electromagnet drive current is detected and immediately after the drive current supply is started. It is known that a step-out is determined when the drive current does not decrease within a predetermined period (Japanese Patent Publication No. 5-57403).
[0003]
There is also an electromagnetically driven valve operating device that is provided with a coil for detecting the displacement of the valve body separately from the drive coil of the electromagnet, and detects the amount of displacement of the valve body based on the self-inductance of this detecting coil. It has been proposed (Japanese Patent Laid-Open No. 7-224624).
[0004]
[Problems to be solved by the invention]
However, in the technique disclosed in Japanese Patent Publication No. 5-57403, a step-out can be detected immediately after the supply of drive current to the electromagnet is started, but even if a step-out occurs during the subsequent holding current supply, it is detected. There is a problem that you can not.
[0005]
In the apparatus disclosed in Japanese Patent Application Laid-Open No. 7-224624, it is necessary to accurately detect a change in the self-inductance of the displacement detection coil. For this purpose, the number of turns of the displacement detection coil must be increased. Therefore, the space for the displacement detection coil is widened, and there is a problem that it is not suitable for a valve operating apparatus for an internal combustion engine having no space.
[0006]
The present invention has been made in view of the above-described points, and an object thereof is to provide a valve operating apparatus for an internal combustion engine that can quickly detect an engine valve step-out with a relatively simple configuration.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is directed to at least one engine valve, an armature member fixed to the engine valve, and an electromagnet for opening and closing the engine valve by applying a force to the armature member. means and, a drive circuit for supplying a drive signal to the electromagnet means, the valve operating system for an internal combustion engine and an elastic means for holding the armature member to the predetermined neutral position, the said armature member and the driving current during energization a flux parameter detecting means for detecting a value of the magnetic flux parameter representing the magnetic flux in the magnetic circuit including the electromagnet means, during the drive current supply to the electromagnet means, based on a magnitude relationship between the value and the predetermined value of the magnetic flux parameter And step-out determination means for determining step-out of the engine valve.
[0008]
According to a second aspect of the present invention, in the valve operating apparatus for an internal combustion engine according to the first aspect, the predetermined value is a value corresponding to a magnetic flux smaller than a magnetic flux generated by a holding current of the electromagnet means. .
[0009]
According to a third aspect of the present invention, in the valve operating apparatus for an internal combustion engine according to the first or second aspect, the out-of-step determining means is configured to detect the out-of-step of the engine valve when the magnitude relationship is reversed at least twice. It is characterized by judging.
[0010]
According to a fourth aspect of the present invention, in the valve operating device for the internal combustion engine according to the first or second aspect, the step-out determination unit is configured so that a predetermined time elapses after the start of supply of drive current to the electromagnet unit. When the magnitude relationship is the same as that at the start of the driving current supply at the time, it is determined that the engine valve is out of step.
[0011]
According to a fifth aspect of the present invention, in the valve operating apparatus for an internal combustion engine according to any one of the first to fourth aspects, the magnetic flux parameter detecting means generates a voltage generated at both ends of a coil provided in the magnetic circuit. Based on this, the magnetic flux parameter value is detected.
[0012]
According to the present invention, the value of the magnetic flux parameter representing the magnetic flux in the magnetic circuit including the armature member and the electromagnet means that is energized with the drive current is detected, and the value of the magnetic flux parameter during the supply of the drive current to the electromagnet means is detected. The step-out of the engine valve is determined based on the magnitude relationship between the engine value and the predetermined value.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0014]
(First embodiment)
FIG. 1 is a diagram showing a configuration of a main part of a valve operating apparatus for an internal combustion engine according to an embodiment of the present invention. In the figure, an engine valve 1 is composed of a valve body 6 to which an armature 3 is fixed and a valve drive unit that drives the valve body 6, and the valve drive unit moves two opposing electromagnets, that is, the valve body 6 in the valve closing direction. The closing electromagnet 8 to be urged, the open electromagnet 9 to urge the valve body 6 in the valve opening direction, and the spring 5 are the main components. The closing side electromagnet 8 includes a coil 4a and a magnetic body (yoke) 2a, and the opening side electromagnet 9 includes a coil 4b and a magnetic body 2b. When the armature 3 is in the neutral position (shown position), the spring 5 has a biasing force against the valve body 6 that is zero, and when the armature 3 is positioned above the neutral position, the spring 5 biases the valve body 6 in the valve opening direction. When positioned below the position, the valve body 6 is configured to be biased in the valve closing direction.
[0015]
The engine valve 1 is mounted on the upper part of the combustion chamber so as to open and close an intake port or an exhaust port of the combustion chamber of the internal combustion engine, for example.
[0016]
According to the above configuration, when the closing electromagnet 8 or the opening electromagnet 9 is energized, the valve body 6 is in the fully closed position where the intake port or the exhaust port is closed and the fully open position where the lift amount of the valve body 6 is maximized. Move between.
[0017]
The coil 4a of the closing electromagnet 8 and the coil 4b of the opening electromagnet 9 are connected to driver circuits 11a and 11b, respectively, and drive current is supplied from these circuits.
[0018]
The driver circuit 11 a includes gate drive circuits 21 and 22, transistors 23 and 24, a current detection circuit 25, a constant current control circuit 26, and a diode 27, and the gate drive circuits 21 and 22 are connected to the control unit 13. ing. The gate drive circuits 21 and 22 control the gate voltages of the transistors 23 and 24, respectively, according to the control signal from the control unit 13, and control the current supply to the coil 4a.
[0019]
The source and drain of the transistor 23 are connected to the power supply line and one end of the coil 4 a, respectively, and the other end of the coil 4 a is connected to the drain of the transistor 24 via the current detection circuit 25. The source of the transistor 24 is grounded. According to this configuration, when both the transistors 23 and 24 are in the on state, the drive current is supplied to the coil 4a through the path of power source → transistor 23 → coil 4a → current detection circuit 25 → transistor 24 → ground.
[0020]
The constant current control circuit 26 controls the gate drive so that the current value when the valve body 6 is held in the fully closed state is constant according to the signal indicating the magnitude of the drive current input from the current detection circuit 25. The gate voltage of the transistor 23 is controlled via the circuit 21. The diode 27 is provided to prevent the generation of excessive back electromotive force.
[0021]
The driver circuit 11 b is configured in the same manner as the driver circuit 11 a, and the drive current supplied to the coil 4 b of the open-side electromagnet 9 is controlled according to the control signal of the control unit 13.
[0022]
A step-out detection coil 7 a wound concentrically with the coil 4 a is provided outside the coil 4 a of the electromagnet 8, and this coil 7 a is connected to the step-out detection circuit 12. The coil 7a generates a voltage proportional to the rate of change of magnetic flux in the magnetic circuit constituted by the magnetic material 2a and the armature 3. Similarly, a step-out detection coil 7 b wound concentrically with the coil 4 b is provided outside the coil 4 b of the electromagnet 9, and this coil 7 b is connected to the step-out detection circuit 12. The coil 7b generates a voltage proportional to the rate of change of magnetic flux in the magnetic circuit constituted by the magnetic material 2b and the armature 3.
[0023]
The step-out detection circuit 12 detects the step-out of the engine valve 1 based on the voltages detected by the coils 7a and 7b, and inputs the detection result to the control unit 13. The control unit 13 performs opening / closing control of the engine valve 1 according to the operating state of the internal combustion engine, and also controls the amount of fuel supplied to the internal combustion engine and the ignition timing of the spark plug. Further, when a step-out of the engine valve 1 is detected, fuel supply to the engine and ignition by the spark plug are stopped, and other engine valves in which no step-out has been detected are stopped, and step-out is further detected. Perform return processing of the engine valve.
[0024]
FIG. 2 is a diagram illustrating a configuration of a main part of the step-out detection circuit 12. In the figure, only the circuit connected to the detection coil 7a is shown, but the circuit connected to the detection coil 7b is the same.
[0025]
One end of the detection coil 7a is connected to the inverting input of the operational amplifier 31 via the resistor R1, and the other end of the detection coil 7a is directly connected to the non-inverting input of the operational amplifier 31. A resistor R2 and a capacitor C1 are connected between the output of the operational amplifier 31 and the non-inverting input and the inverting input, respectively. The operational amplifier 31, the resistors R1 and R2, and the capacitor C1 constitute an integrating circuit, thereby constituting a magnetic flux detector. The magnetic flux detection unit integrates the voltage VCOIL across the coil 7a and outputs a magnetic flux voltage Vφ that is proportional to the magnetic flux in the magnetic circuit including the magnetic material 2a and the armature 3. In this circuit, the polarity of the magnetic flux voltage Vφ is inverted with respect to the coil voltage VCOIL.
[0026]
That is, since the coil voltage VCOIL = −N (dφ / dt) (N is the number of turns of the detection coil, φ is the magnetic flux in the magnetic circuit), the magnetic flux voltage proportional to the magnetic flux φ is obtained by integrating this. Vφ is obtained.
[0027]
The magnetic flux voltage Vφ is input to the non-inverting input of the comparator 32 that constitutes the step-out detection unit, and the reference voltage VREF is input to the inverting input of the comparator 32. The comparator 32 inputs the first detection signal VDET1, which is high when Vφ> VREF and low when Vφ <VREF, to the step-out detection timing adjustment unit.
[0028]
The step-out detection timing adjustment unit includes a D flip-flop circuit 33 and an AND (logical product) circuit 34, and the first detection signal VDET 1 is supplied to the clock input CK of the D flip-flop circuit 33 and one input of the AND circuit 34. Is done. The Q bar output of the D flip-flop circuit 33 is connected to the D input, and the Q output is connected to the other input of the AND circuit 34. The clear input CL of the D flip-flop circuit 33 is supplied with an energization signal that is at a low level during energization of the coil 7a and becomes high at the end of energization. The output of the AND circuit 34 is input to the control unit 13 as the second detection signal, that is, the step-out detection signal VDET2.
[0029]
Next, the operation of the apparatus shown in FIGS. 1 and 2 will be described.
[0030]
FIG. 3 shows the lift amount LIFT of the valve body 6 when the engine valve 1 is opened (normal operation) in (a) (LIFT = 0 when in the fully closed position), and (b). It is a figure which shows transition of the coil current ICOIL which flows into the coil 4b of the valve opening side electromagnet 9, the voltage VCOIL of the both ends of the coil 7b to (c), and the magnetic flux voltage Vphi output from the magnetic flux detection part to (d). As is apparent from this figure, a relatively large current is supplied at the beginning of energization of the coil, and when the fully open state of the engine valve 1 is stabilized, the current value is decreased and a relatively small holding current is supplied.
[0031]
FIG. 4 is a diagram for explaining the operation of the step-out detection circuit 12. The solid line, the broken line, and the alternate long and short dash line in FIG. 4 indicate the normal operation, the case where the valve body 6 hardly moves from the neutral position, and The characteristic when an abnormality occurs in the fully opened state and the valve body 6 vibrates is shown. Here, (a) in the figure shows the lift amount LIFT of the valve body 6 when the engine valve 1 is opened, (b) shows the magnetic flux voltage Vφ, (c) shows the first detection signal VDET1, (d) shows The step-out detection signal VDET2 is shown.
[0032]
In this embodiment, the reference voltage VREF is set to a negative value whose absolute value is smaller than the magnetic flux voltage Vφ when the holding current is supplied during normal operation, as shown in FIG. As is apparent from this figure, the absolute value of the magnetic flux voltage Vφ is smaller at the time of step-out than at the time of normal operation. This is because the gap between the armature 3 and the magnetic material 2a or 2b during normal operation is minimized and the magnetic resistance is reduced, whereas the gap is increased and the magnetic resistance is increased during step-out. The present embodiment focuses on this point and detects step-out. The step-out detection method will be described in detail below.
[0033]
First, in the normal operation, as indicated by a solid line in FIG. 5C, the first detection voltage VDET1 changes from the high level to the low level at time t1 when the magnetic flux voltage Vφ falls below the reference voltage VREF, and at time t4. When the energization of the coil 4b is finished, the reference voltage VREF is exceeded immediately after that. The D flip-flop circuit 33 outputs the D input to the Q output at the rise of the clock input CK. However, since the energization signal becomes a high level at time t4, the Q output does not change even if the clock input CK rises after time t4. The low level is maintained, and the step-out detection signal VDET2 is also maintained at the low level (solid line in FIG. 4D).
[0034]
When the neutral position of the valve body 6 hardly moves (indicated by a chain line), the magnetic flux voltage Vφ falls below the reference voltage VREF at time t1, and exceeds the reference voltage VREF at time t2. As a result, the first detection voltage VDET1 rises from the low level to the high level at time t2, the Q output of the D flip-flop 33 changes from the low level to the high level, and at the same time, the output of the AND circuit 34, that is, the step-out detection signal VDET2 Will also be high. When the energization signal becomes high level at time t4, the Q output of the D flip-flop circuit 33 becomes low level, so the step-out detection signal VDET2 also becomes low level.
[0035]
When the valve body 6 starts to vibrate from the fully open position (indicated by a one-dot chain line), it operates in the same manner as normal until the vibration starts, and when the vibration starts, the magnetic flux voltage Vφ is changed to the reference voltage VREF at time t3. Over. Accordingly, the step-out detection signal VDET2 becomes high level at this time. The subsequent operation is the same as that of the broken line.
[0036]
In addition, although the above-mentioned description respond | corresponds to the step-out detection at the time of valve opening operation based on the detection voltage of the detection coil 7b provided in the valve opening side electromagnet 9, it was provided in the valve closing side electromagnet 8. The step-out detection during the valve closing operation based on the detection voltage of the detection coil 7a is similarly performed.
[0037]
As described above, in this embodiment, focusing on the fact that the magnetic flux in the magnetic circuit including the armature 3 is smaller at the time of step-out than in the normal state, the magnetic flux voltage Vφ representing the magnetic flux in the magnetic circuit including the armature 3 and the reference voltage Since the out-of-step of the engine valve 1 is detected based on the magnitude relationship with VREF, for example, even when the engine valve 1 does not operate at all or when the step-out occurs during the valve opening operation, the out-of-step can be detected quickly. Can do. Further, the detection coils 7 a and 7 b need only be able to detect a change in magnetic flux in the magnetic circuit constituted by the electromagnet and the armature 3, so that it is not necessary to increase the number of turns so much, and the detection coils 7 a and 7 b can be mounted in a small space. it can.
[0038]
(Second Embodiment)
In the first embodiment, step-out detection is performed by the step-out detection circuit shown in FIG. 2, but in this embodiment, the magnetic flux voltage Vφ (magnetic flux detection unit output) is input to the control unit 13 as it is, The processing shown in FIG. 5 is executed by a CPU (not shown) of the control unit 13 to detect step-out. The other points are the same as in the first embodiment. The processing in FIG. 5 is executed every predetermined time.
[0039]
First, in step S1, it is determined whether or not the coil 4a (or 4b) is energized. If it is energized, it is determined whether or not the magnetic flux voltage Vφ is lower than the reference voltage VREF (step S2). When the coil 4a (or 4b) is not energized or when Vφ> VREF, this processing is immediately terminated.
[0040]
If Vφ <VREF, the process proceeds to step S3, where it is determined whether the energization to the coil 4a (or 4b) has been completed. If not, it is determined whether the magnetic flux voltage Vφ has exceeded the reference voltage VREF. (Step S4). As a result, when Vφ <VREF, the process returns to the step S3, and when the energization to the coil 4a (or 4b) is finished, this process is finished.
[0041]
If Vφ> VREF before the end of energization, it is determined that a step-out has occurred, and the process proceeds to step S5 to perform the following step-out detection corresponding operation. That is, fuel supply to the engine and ignition by the spark plug are stopped, other engine valves in which step-out is not detected are stopped, and return processing of the engine valve in which step-out is detected is performed.
[0042]
In this embodiment, the functions realized by hardware in the first embodiment are realized by software, and the same effects as those of the first embodiment are obtained.
[0043]
(Third embodiment)
In the present embodiment, step-out detection is performed by the process shown in FIG. 6 instead of the process of FIG. 5 in the second embodiment. The other points are the same as in the second embodiment.
[0044]
Steps S1, S3 and S5 in FIG. 6 are the same as the processing in FIG. In step S11, it is determined whether or not a predetermined time TDET has elapsed from the start of energization of the coil 4a (or 4b). When the energization has not ended after the lapse of the predetermined time TDET, it is determined whether or not the magnetic flux voltage Vφ is higher than the reference voltage VREF (step S12). If Vφ ≦ VREF, this processing is terminated, and Vφ> If it is VREF, it is determined that the step-out has occurred, and the process proceeds to step S5.
[0045]
Here, the predetermined time TDET is set to a time slightly longer than the rise time of the magnetic flux based on, for example, an average coil energization time (drive current supply time).
[0046]
If the elapse time of the predetermined time TDET is between the times t3 and t4 in FIG. 4, according to this embodiment, the step-out can be quickly detected with a simple configuration as in the above-described embodiment.
[0047]
(Other embodiments)
The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, although the case where the magnetic flux voltage Vφ is a negative voltage has been described in the above-described embodiment, it can be easily set to a positive voltage by reversing the polarity. In that case, if the reference voltage VREF is also set to a positive voltage and the determination is made by reversing the magnitude relationship between the magnetic flux voltage Vφ and the reference voltage VREF, step-out detection can be performed as in the above-described embodiment. That is, in the first and second embodiments, when the magnitude relationship is reversed at least twice during coil energization, it is determined that the step is out of step, and in the third embodiment, the magnitude relationship when the predetermined time TDET has passed is determined. When it is the same as the magnitude relationship at the start of energization, it is determined that the step-out.
[0048]
The magnetic flux in the magnetic circuit including the armature 3 may be detected using a magnetic detection element such as a Hall element instead of the coils 7a and 7b.
[0049]
【The invention's effect】
As described above in detail, according to the present invention, the value of the magnetic flux parameter representing the magnetic flux in the magnetic circuit including the armature member and the electromagnet means that is energized with the drive current is detected, and the drive current is being supplied to the electromagnet means. Since the engine valve step-out is determined on the basis of the magnitude relationship between the magnetic flux parameter value and the predetermined value, the engine valve step-out detection can be quickly performed with a relatively simple configuration.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a valve gear according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration of a step-out detection circuit in FIG. 1;
FIG. 3 is a diagram for explaining the operation of the apparatus shown in FIG. 1;
FIG. 4 is a diagram for explaining the operation of a step-out detection circuit;
FIG. 5 is a flowchart of a step-out detection process according to the second embodiment.
FIG. 6 is a flowchart of a step-out detection process according to a third embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine valve 2a, 2b Magnetic material 4a, 4b Coil 5 Spring 6 Valve body 7a, 7b Out-of-step detection coil 8 Closed-side electromagnet 9 Open-side electromagnet 12 Out-of-step detection circuit

Claims (5)

At least one engine valve, an armature member fixed to the engine valve, electromagnet means for opening and closing the engine valve by applying a force to the armature member, and a drive circuit for supplying a drive signal to the electromagnet means And a valve operating apparatus for an internal combustion engine comprising elastic means for holding the armature member in a predetermined neutral position.
Magnetic flux parameter detection means for detecting a magnetic flux parameter value representing a magnetic flux in a magnetic circuit including the armature member and the electromagnet means that is energized with a drive current , and the magnetic flux parameter in the drive current supply to the electromagnet means A valve operating apparatus for an internal combustion engine, comprising: a step-out determining unit that determines a step-out of the engine valve based on a magnitude relationship between a value and a predetermined value.   2. The valve operating apparatus for an internal combustion engine according to claim 1, wherein the predetermined value is a value corresponding to a magnetic flux smaller than a magnetic flux generated by a holding current of the electromagnet means.   3. The valve operating apparatus for an internal combustion engine according to claim 1, wherein the step-out determination unit determines that the engine valve has stepped out when the magnitude relationship is reversed at least twice.   The out-of-step determining means is configured to detect the out-of-step of the engine valve when the magnitude relationship is the same as that at the start of the supply of the drive current after a predetermined time has elapsed since the start of supply of the drive current to the electromagnet means. The valve operating apparatus for an internal combustion engine according to claim 1 or 2, wherein the determination is made.   5. The internal combustion engine according to claim 1, wherein the magnetic flux parameter detection unit detects the magnetic flux parameter value based on a voltage generated at both ends of a coil provided in the magnetic circuit. Valve operating device.

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