JPH10154617A - Failure judging device of electromagnet device, flow rate control device, and fuel injector of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the failure of an electromagnetic device including a pair of coils. SOLUTION: Coils L11 and L12 of an electromagnet device 17 are excited or demagnetized according to the state of switching circuits 19 and 20 that are controlled by first and second control signals from a signal generation circuit 22. Comparison circuits 27 and 29 discriminate the levels of the first and second comparison signal of connection points P11 and P12 between the coils L11 and L12 and the switch circuits 19 and 20 and generate first and second comparison signals. Failure judgment circuits 28 and 30 compare the change patterns of the signal levels of a comparison signal and a control signal using the continuation time of the high level of the comparison signal and the pulse training timing of the comparison signal, and judges that there is no failure when the change pattern matches and that there is a failure when it matches, thus judging the presence of absence of the failure in the electromagnet device 17 even if the mutual inductance of the coils L11 and L12 is large.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure determination device for determining a failure of an electromagnet device having a plurality of coils, a flow control device having the electromagnet device, and a fuel injection device for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, a flow control valve is provided in an internal combustion engine of a vehicle separately from a throttle valve in order to control the number of revolutions in an idle state. The flow control valve is mounted in a bypass pipe provided to bypass the throttle valve in an intake pipe for introducing intake air to the internal combustion engine, and increases or decreases the air flow rate of the bypass pipe to the internal combustion engine. Adjust the amount of intake air supplied. As a flow control valve for this idle control, for example, there is a valve called a rotary idle speed control (hereinafter abbreviated as “R-ISC”).

[0003] The R-ISC valve uses a cylinder having a notch on a side surface as a valve body and angularly displaces the valve body around a central axis parallel to the side surface to thereby provide an auxiliary conduit at a place where the valve body is installed. , That is, the valve opening degree is changed. As a driving device for angularly displacing the valve body, an electromagnet device having a pair of coils is used. The drive device maintains a desired valve opening by mutually exciting the pair of coils by a method described later.

At present, in the idling speed control method of the internal combustion engine, it is required to increase the air flow rate in the bypass line via the flow control valve. For example, the flow rate per unit time of the current flow control valve is about 2000 cc, but the flow rate per unit time is about 3000 cc to 50 cc.
It is required to increase to 00 cc. As the air flow rate in the bypass line increases, the influence of the variation in the valve opening degree of the bypass line on the intake air amount of the internal combustion engine increases. For example, when an abnormality occurs in the above-described drive device, the valve opening of the flow control valve cannot be adjusted. In this case, if the air flow rate in the bypass line is large, the ratio of the intake air from the bypass line in the total intake air amount is large, so that the intake air amount is increased above the desired amount or decreased below the desired amount. Can be considered. As a result, there arises a problem that the rotation speed of the internal combustion engine is increased to be equal to or higher than the idle rotation speed, or the rotation speed is reduced to less than the idle rotation speed and the internal combustion engine is stopped. Therefore, as the flow rate of the flow control valve increases, it is required to add a fail-safe function to the drive circuit to prevent the above-described inconvenience.

FIG. 11 is a circuit diagram for explaining an electric configuration of a flow control device 1 including a driving device for the above-described flow control valve and the first prior art. FIG.
FIG. 4 is a waveform chart for explaining a failure detection technique in one flow control device 1. 11 and 12 will be described together.

The coils L1 and L2 have one terminal connected to a power supply line and the other terminal connected to a control transistor T.
1 and T2 are connected to the ground line. The coils L1 and L2 are components constituting an electromagnet device of the driving device. When each of the coils L1 and L2 is individually excited, the valve body 3 of the flow control valve increases and decreases the valve opening of the flow control valve. Angular displacement in each direction.

The gate terminals of the transistors T1 and T2 are supplied from the processing circuit 5 to the first terminals shown in FIGS.
And a second control signal are provided. The first and second control signals are rectangular pulse signals having the same duty ratio and mutually inverted phases. Transistors T1, T
Reference numeral 2 denotes an on state in which a current can pass when the signal level of each control signal is high, and an off state in which the current is interrupted when the signal level is low. Since the first and second control signals are rectangular pulse signals, the signal levels alternately maintain high and low levels according to the duty ratio.

At this time, the processing circuit 5 includes coils L1, L2
Circuit relating to the control of the excitation / demagnetization operation of FIG.
The failure detection operation is performed on each of the two power supply paths. Since the failure detection method for each power supply path is the same,
A power supply path from the power supply line to the ground line via the coil L1 and the transistor T1 will be described as an example. The processing circuit 5 first detects a signal level change of an electric signal appearing at a connection point P1 between the coil L1 and the transistor T1. Next, during one signal cycle of the first control signal, it is detected whether or not the signal level of the electric signal at the connection point P1 has changed from a level higher than a predetermined reference level to a level lower than the reference level. This reference level is, for example, the coil L1
When the signal level of the electric signal at the time of excitation is 13 V,
It is set to 2.5V.

When there is no failure such as disconnection or short-circuit in the power supply path, power is supplied to and cut off from the power supply path according to the on / off state of the transistor T1. At this time, the signal level of the electric signal at the connection point P1 is alternately switched between a high level and a low level in synchronization with the first control signal as shown in FIG. When the transistor T1 fails and keeps the off state, the power of the power supply path is not supplied, so that the above signal level always keeps a low level lower than the reference level.

From these, the processing circuit 5 detects whether or not the signal level of the electric signal has changed across the reference level within a certain signal period W1 of the first control signal,
When there is no change, it is determined that there is a failure. For example, as for the signal level of the electric signal, the level switching described above occurs at the falling time t1 of the rectangular pulse of the first control signal only when there is no failure in the power supply path. Then, the presence or absence of a failure is determined.

In the flow rate control device 1 described above, the iron cores of the coils L1 and L2 may be formed of a common iron bar in order to reduce the size of the driving device. At this time, the mutual inductance between the coils L1 and L2 is extremely high. In the flow control device 1 having this structure, when the transistor T1 fails to maintain the OFF state and the coil L2 operates normally, the coil L1 is driven by mutual induction between the coils L1 and L2.
, A level change occurs in the electric signal at the connection point P1. As shown in FIG. 12 (4), this level change sharply increases and decreases in synchronization with the falling and rising of the pulse of the second control signal, that is, the rising and falling of the pulse of the first control signal. And
Thereafter, the level gradually decreases or increases. At this time, since the mutual inductance of the coils L1 and L2 is large, the signal level may be lower than the aforementioned reference level. This level switching occurs at the rising time of the rectangular pulse of the second control signal, that is, at the falling time t1 of the pulse of the first control signal, for example, in synchronization with the second control signal to the coil L2. Thus, the coils L1, L
When the mutual inductance between the two is large, the electric signal at the connection point P1 during abnormal operation behaves similarly to the electric signal at the connection point P1 during normal operation.

Therefore, when the presence or absence of a failure is determined by the above-described failure determination method, the processing circuit 5 detects level switching at time t1 and determines that there is no failure. As described above, when the mutual induction between the coils L1 and L2 is extremely large, it is difficult to determine the failure of the transistors T1 and T2 of the flow control device by the above-described failure determination method.

The present applicant has proposed a failure detecting device disclosed in Japanese Patent Application Laid-Open No. 3-118486 as a second prior art for determining a failure of an electromagnet device including a plurality of coils. This device detects disconnection and short-circuit of a solenoid load including a plurality of coils connected in parallel between a power supply line and a ground line. For this reason, the device starts from the power supply start timing to the solenoid load,
The time until the signal level of the electric signal appearing at the terminal on the ground line side of all the coils reaches a predetermined voltage is measured. In this solenoid load, the level of the electric signal changes with time and gradually increases, and the time measured in the normal operation and the abnormal operation is different, so that the time measured is the time measured in the normal operation. By comparing with the reference time, the presence or absence of disconnection and short circuit of the coil is detected.

In the above-described flow control device 1 having a large mutual inductance, even when a failure occurs in the device 1, the level of the electric signal instantaneously changes at the level switching timing of the first and second control signals. The time required for the level to reach the predetermined voltage is the same during normal operation and abnormal operation. Therefore, it is difficult for the apparatus of this publication to detect the presence or absence of a failure in the flow control device 1 described above.

As a third prior art for solving the above-mentioned problem, there is an idle control valve abnormality detecting device disclosed in Japanese Patent Laid-Open Publication No. Hei 6-146978. In this device, an abnormal operation of the idle control valve having the same structure as the flow control device 1 described above is detected. For this reason, the device
An electric signal appearing at each terminal on the ground line side of the pair of coils is differentiated to detect only the rise and fall of the pulse of the electric signal, and the presence or absence of the rise and fall is detected using a flip-flop circuit.

As described above, in a device having a pair of coils, when the mutual inductance of the pair of coils is large and a disconnection occurs on the downstream side of the power supply path from the terminal, the above-described FIG. As shown, the electric signal periodically changes abruptly. Since this device does not take into account mutual induction between the coils, the change point of the level of the electric signal at this time is detected as the rising and falling of the pulse. Therefore, it is difficult for the apparatus of this publication to detect the presence or absence of a failure in the above-described flow control valve driving device.

[0017]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electromagnet device failure judging device capable of judging the presence / absence and location of a fault in an electromagnet device including a pair of coils having a large mutual inductance. An object of the present invention is to provide a fuel injection device including an electromagnet device and a flow control device.

[0018]

According to the present invention, there is provided an electromagnet apparatus having a pair of first and second coils which are magnetically coupled to each other and connected in series to the first coil. In the state, the first coil is demagnetized.
A switching means connected in series to the second coil, the second coil is excited when in a conductive state, and the second coil is
A second switching means for demagnetizing the coil, a first control signal for turning on / off the first switching means, and a second control signal for turning on / off the second switching means, the first and second controls The signal is generated during a first period in which the first switching unit is in a conducting state and the second switching unit is in a blocking state, and in a second period when the first switching unit is in a blocking state.
Signal generating means for duty-controlling the first and second switching means so as to have a second period in which the switching means is in a conductive state; and a signal of an electric signal at a first connection point between the first coil and the first switching means. Comparing means for discriminating the level at a predetermined discrimination level, and comparing a change pattern of the signal level of the electric signal at the first connection point with a change pattern of the signal level of the first control signal in response to an output from the comparing means. And a failure determination unit for determining failure of the electromagnet device. According to the present invention, the pair of coils of the electromagnet device are individually excited or demagnetized by duty control using the first and second control signals from the signal generating means. Each coil is turned on or off by switching means individually connected in series with each coil in accordance with the signal level of each control signal, so that the presence or absence of power supply to each coil is switched, so that excitation and demagnetization are performed. Are alternately repeated with time. This makes it possible to arbitrarily change the average value of the strength of the magnetic field of each coil for a certain period according to the duty ratio of each control signal. The failure detection means is
A failure such as a disconnection of a first circuit including the first coil and the first switching means and a disconnection of a signal transmission path between the first switching means and the signal generation means are detected.
The presence / absence of the failure of the first circuit is determined in response to the comparison result of the electric signal from the comparing means, the change pattern of the signal level of the electric signal at the first connection point between the first coil and the first switching means, The determination is made by comparing a change pattern of the signal level of the first control signal. The fact that this operation can determine the presence or absence of a failure will be described below. For example, the first
When the first coil operates normally without any circuit failure, the first
Whether or not power is supplied to the circuit is switched in response to a change in the state of the first switching means, that is, a change in the signal level of the first control signal. At this time, the level of the electric signal
Assuming that the switching means keeps the first and second levels when the switching means is in the conduction and cutoff states, respectively, and the levels VL and VH in FIG. 4, the signal level of the first control signal shown in FIG. The level of the electric signal is switched only at the timing corresponding to the level corresponding to the switching.
FIG. 4 (3) shows a waveform diagram of this electric signal. As a result, the change timings of the signal levels of the first control signal and the electric signal coincide. Also, for example, when the first circuit has the above-described failure, power is not supplied to the first circuit regardless of a change in the state of the first switching means. In this case, when the second coil operates normally, the first and second coils are magnetically coupled as described above, so that the first coil is caused by mutual induction between the first and second coils. An induced current is generated. This induced current is divided into the first and second
The greater the mutual inductance between the coils, the greater the value. The induced current causes the behavior of the signal level of the electric signal at the first connection point to differ depending on the location of the failure in the first circuit. For example, when the first coil is disconnected, the induced current is not transmitted to the first connection point, so that the signal level of the electric signal at the first connection point always keeps one of the first and second levels. When the discrimination level of the comparison means is a level between the first and second levels of the electric signal, the electric signal always keeps a level higher than or lower than the discrimination level. FIG. 4 (7) shows a waveform diagram of this electric signal. Also, the first
When the switching means fails so as to always maintain the cutoff state, and when the signal transmission path is broken, the electric signal at the first connection point changes in signal level by the induction current being transmitted to the first connection point. . The change timing of the signal level of the electric signal is synchronized with the change timing of the signal level of the second control signal. Further, specifically, the change pattern of the signal level instantaneously reaches the maximum value or the minimum value at the change timing of the second control signal, and decreases or increases with time from the change timing. FIG. 4 (5) shows a waveform diagram of the electric signal. The above-described maximum value and minimum value correspond to the levels VH and VL, respectively. Thus, when the induced current is concerned with the behavior of the signal level of the electric signal, the behavior of the signal level of the first control signal and the electric signal is as follows:
No one-to-one correspondence. The width between the maximum value and the minimum value of the electric signal increases as the mutual inductance between the pair of coils increases. For this purpose, the signal level of the electrical signal is
At the first timing reaching the maximum value or the minimum value, the level may change from a level higher than the discrimination level to a level lower than the discrimination level, or vice versa. At this time, since the signal level increases or decreases after the level change, the signal level is again changed from a level lower than the discrimination level to a level higher than the discrimination level at an arbitrary second timing within a period during the level aging from the first timing. Or vice versa. In this case, when the change timings of the signal levels of the first and second control signals are different, the first and second timings are all different from the change timing of the first control signal. In this case, when the change timings of the first and second control signals match, at least the second timing is different from the change timing of the first control signal. Thus, by comparing the change pattern of the signal level between the first control signal and the electric signal based on the level discrimination result of the electric signal, the above-mentioned difference in behavior is detected, and the failure of the first circuit is detected. Presence or absence can be detected.

Further, according to the present invention, the comparing means generates a comparison signal which maintains a predetermined one level when the level of the electric signal is lower than the discrimination level and maintains a predetermined other level when the level is higher than the discrimination level. The failure determination means is
From the change timing of the signal level of the first control signal,
A timer for measuring the duration during which the comparison signal keeps one level or the other level, and a holding time during which the first switching means is kept in a conductive state or a cut-off state by the first control signal. And a determination unit that determines that there is a failure when the continuation time does not match the holding time. According to the present invention, the failure determining means determines the presence or absence of a failure by comparing the duration of the comparison signal from the comparing means with the holding time of the first switching means. One and the other levels of the comparison signal respectively correspond to a high level and a low level in the waveform diagram of FIG.
The duration of one or the other level of the comparison signal indicates a period in which the signal level of the electric signal is lower than or higher than the discrimination level as described in claim 1, and the level change timing of the comparison signal is Indicates a change timing at which the signal level changes from the discrimination level to the discrimination level, or vice versa. When there is no failure in the first circuit, the electric signal maintains one of the first and second levels in one-to-one correspondence with the state change of the first switching means. Therefore, the comparison signal is
In synchronization with the change timing of the first control signal, the level is switched to one of the first and other levels, and the level is maintained until the next change timing. As a result, the continuation time matches the holding time. When the first circuit has the above-described disconnection failure of the first coil, the electric signal always keeps one of the first and second levels, so that the comparison signal keeps one of the other and the other level, and the duration is It can be either zero or infinity. When the observation period of this time is longer than the time corresponding to one cycle of the signal cycle of the first control signal, the conduction and cutoff states of the first switching means are alternately switched.
The retention time is a finite time that is greater than 0 and shorter than the observation period. Therefore, the duration and the holding time do not match. If the first circuit has the above-mentioned disconnection failure of the first switching means and the above-mentioned disconnection failure of the signal transmission circuit, when the mutual inductance is small, the amount of change in the signal level is small. Keep your level. The comparison signal at this time is the same as the comparison signal when the first coil has the above-described failure. In the above case, when the mutual inductance is large, the amount of change in the signal level is large, and the signal level of the electric signal fluctuates above or below the discrimination level, so that the comparison signal is one of the first and second timings described in claim 1. Switch to the other level. The continuation time at this time is a time between the first and second timings. This duration is independent of the holding time of the first and second switching means, since at least the second timing does not coincide with the level change timing of the first control signal. Therefore, the duration and the holding time do not match. From these facts, it can be seen that the presence or absence of a failure can be determined by comparing the duration and the holding time.

Further, according to the present invention, when the duration does not coincide with the holding time and the duration is less than a predetermined time, the determining means may cause a failure in the path on the first coil side from the first connection point. It is determined that there is a failure, and when there is no match and the duration is longer than a predetermined time, it is determined that there is a failure in the path on the first switching means side from the first connection point. According to the present invention, when it is determined that there is a failure, the determination unit determines the location of the failure in the first circuit according to the absolute length of the duration. As described in claim 2, the factor that defines the duration is different depending on the failure location. In particular, when there is a failure of the above-described disconnection in the path on the first coil side of the first circuit, the duration is either 0 or coincides with the observation period, and the path of the above-described disconnection in the path on the first switching means side. It is sufficiently shorter or longer than the duration when there is a failure. Therefore, a predetermined threshold time is determined so as to detect only the duration of the first coil failure, and the duration of the second circuit is determined by determining the length of the duration based on this time. Can be.

Further, according to the present invention, the comparing means generates a comparison signal that maintains a predetermined one level when the level of the electric signal is lower than the discrimination level and maintains a predetermined other level when the level is higher than the discrimination level. The failure determination means is
The time is counted from a point in time when the first switching means switches from one of the conduction state and the interruption state to the other state by the first control signal by a time determined in accordance with the duty ratio of the first control signal. Detecting means for detecting the presence or absence of a level change of the comparison signal within a predetermined determination period, and responding to the output of the detecting means, determining that there is no failure when there is a level change, and no failure when there is no level change And determining means for determining. According to the present invention, the failure determination unit detects whether or not the level of the comparison signal from the comparison unit has changed during the determination period including the level change timing of the first control signal that is a rectangular pulse signal. , The presence or absence of the failure of the first circuit is determined. The behavior of the comparison signal when there is no failure, when the above-mentioned disconnection failure occurs in the first coil, and when there is the above-mentioned disconnection failure in the first switching means, is the same as the behavior described in claim 2. Therefore, the description is omitted. When there is no failure in the first circuit, the signal level of the comparison signal switches in synchronization with the change timing of the first control signal, and maintains that level until the next change timing. Accordingly, when the first switching means switches from one of the conduction state and the interruption state to the other state in synchronization with the level change of the first control signal, the signal level of the comparison signal is simultaneously changed from one level to the other. Switch to level. When the first circuit has the above-mentioned disconnection failure of the first coil, the comparison signal keeps one of the other and the other level, and there is no level switching. If the first circuit has the above-described disconnection failure of the first switching means and the above-described signal transmission circuit has the above-mentioned disconnection failure, and the mutual inductance is small, the comparison signal indicates that the first coil has the above-mentioned failure. Since it is the same as the comparison signal, there is no level switching. In the above case, when the mutual inductance is large, for example, the comparison signal switches from the other level to the one level at the first timing described above, and switches from the one level to the other level at the second timing. This second timing does not coincide with the timing at which the state of the first switching means switches. From this, there is no failure of the first circuit within the determination period including the above-mentioned timing of the first control signal and counting the time after the above-mentioned second timing of the comparison signal as the above-mentioned backward time. Only when is the level of the comparison signal changed can be seen. Thus, the presence or absence of a failure in the first circuit can be determined by detecting whether or not the level of the comparison signal has changed during the determination period.

Also, in the present invention, the comparing means generates a comparison signal that maintains a predetermined one level when the level of the electric signal is lower than the discrimination level and maintains a predetermined other level when the level is equal to or higher than the discrimination level. The failure determination means is
A forcing means for keeping the first switching means in a conductive state or a cut-off state during a predetermined inspection period, a detecting means for detecting the presence or absence of a level change of a comparison signal during the inspection period, and a level change in response to an output of the detecting means. Determining that there is no failure when there is no error, and determining that there is a failure when there is a level change. According to the present invention,
The failure determination means forcibly keeps the first switching means in a conductive state or a cutoff state only during a test period, and determines the behavior of the comparison signal during the same by the same method as in the fourth switching means. Of the above-described disconnection and the presence or absence of the above-described disconnection failure of the signal transmission path.
This failure determination method is based on the premise that there is no failure in the first coil. This inspection period corresponds to the inspection period W30 in the waveform diagram of FIG. The meaning of the comparison signal is the same as the meaning described in claim 2. When it is assumed that the first switching means is kept in the conducting state during the inspection period and there are no two failures as described above, the comparison signal is synchronized with the behavior of the first switching means. There is no. The waveform diagram of the comparison signal at this time is shown in FIG.
This is shown in (4). When there is at least one of the above-mentioned faults and there is mutual inductance, the electric signal fluctuates due to the induced current of mutual induction. In this case, when the mutual inductance is sufficiently large, a level change occurs in the comparison signal. FIG. 9 (6) shows a waveform diagram of this comparison signal. Thus, the presence or absence of a change in the level of the comparison signal during the inspection period differs depending on whether or not there is a failure. Thereby, the failure of the first switching of the first circuit can be detected by the above-described method.

In the present invention, the failure judging means may include a forcing means for keeping the first switching means in a conductive state or a cut-off state during a predetermined inspection period, and a signal level of the electric signal within the inspection period. When keeping above
It is determined that there is no failure in the path on the first switching means side from the first connection point, and when the signal level falls below the discrimination level within the inspection period, it is determined that there is a failure in the path on the first switching means side. And determining means. According to the present invention, the failure determination means forcibly keeps the first switching means in a conductive state or a cut-off state only during a test period, and determines the behavior of the electric signal during the period, so that the failure of the first switching means is reduced. It is determined whether the above-mentioned disconnection failure and the above-mentioned disconnection failure of the signal transmission path exist.
This failure determination method is based on the premise that there is no failure in the first coil. This inspection period corresponds to the inspection period W30 in the waveform diagram of FIG. The meaning of the comparison signal is the same as the meaning described in claim 2. For example, when it is assumed that the first switching means is kept in the conducting state during the inspection period, when there is no failure at the above-mentioned two points, the level change of the electric signal is synchronized with the behavior of the first switching means. Keep the corresponding first level. FIG. 9 (3) shows a waveform diagram of the electric signal at this time. When there is at least one disconnection failure as described above and there is mutual inductance, the electric signal fluctuates due to the induced current of mutual induction.
In this case, when the mutual inductance is sufficiently large, the signal level of the electric signal falls below the discrimination level in synchronization with the level change timing of the second control signal. FIG. 9 (5) shows a waveform diagram of this electric signal. As described above, the behavior of the electric signal during the inspection period differs between when there is a failure and when there is no failure. Thereby, the failure of the first switching of the first circuit can be detected by the above-described method. Also, in this method, it is not necessary to generate a comparison signal as compared with the method of claim 5, and a means for that purpose can be omitted, so that the structure of the device is simplified.

[0024] In the present invention, the failure judging means may be configured such that, when the level of the electric signal at the first connection point is kept below another predetermined discrimination level that is equal to or lower than the discrimination level during the inspection period. Disconnection that determines that there is a failure in the path on the first coil side from the point, and determines that there is no failure in the path on the first coil side from the first connection point when the level becomes another discrimination level or more within the inspection period. It is characterized by further including a judging means. According to the present invention, the failure determination means according to claims 5 and 6 further determines the failure of the first coil by using the disconnection determination means during the inspection period. In the case where it is assumed that the conductive state is maintained during the inspection period,
When there is no failure in the coil, the electric signal keeps the first level corresponding to the conduction state of the first switching means as described above. When there is a failure in the first coil, the second level corresponding to the shut-off state of the first switching means is maintained. Since this second level is below the discrimination level,
When the above-mentioned another discrimination level is set to a level larger than the second level and equal to or smaller than the discrimination level, it is determined whether or not the level of the electric signal is the second level.
It is possible to determine whether or not the first coil has a failure. Also,
When the first switching means has the above-described failure and the mutual inductance is small, the electric signal exhibits almost the same behavior as that at the time of the failure of the first coil. Therefore, the presence or absence of the failure can be determined by this method.

According to the present invention, valve means having a valve interposed in a fluid passage through which a predetermined fluid passes, opening degree determining means for outputting an instruction signal indicating the valve opening degree of the valve means, and magnetically coupled thereto. A pair of first and second coils, the first coil displacing the valve body in a direction in which the valve opening increases, and the second coil displacing the valve body in a direction in which the valve opening decreases. A first switching means connected in series with the first coil, the first coil is excited when in a conductive state, and the first coil is demagnetized in a cut-off state; A second switching means in which the two coils are excited and the second coil is demagnetized when in the cut-off state; and a first switching means in response to an instruction signal from the opening determination means, wherein a duty ratio corresponding to the valve opening is determined mutually. And the second
A first control signal for turning on / off the first switching means and a second control signal for turning on / off the second switching means, wherein the first and second control signals are the first and second control signals. The first and the second so as to have a first period in which the switching means is in a conducting state and the second switching means is in a blocking state, and a second period in which the first switching means is in a blocking state and the second switching means is in a conducting state. Signal generating means for duty controlling the switching means, first comparing means for level discriminating a signal level of the first electric signal at a first connection point between the first coil and the first switching means at a predetermined discrimination level, By comparing the change pattern of the signal level of the first electric signal with the change pattern of the signal level of the first control signal in response to the output from the comparing means, A first failure determining means determines the failure of the first power supply path including the first coil and the first switching means, the second and the second coil and the second switching means
A second comparing means for discriminating the signal level of the second electric signal at the connection point at a predetermined discrimination level; a change pattern of the signal level of the second electric signal in response to an output from the second comparing means; By comparing the control signal with the change pattern of the signal level, the second coil and the second coil are compared.
And a second failure determination unit that determines a failure of the second power supply path including the switching unit. According to the present invention, in a flow control device including a valve means for controlling a predetermined flow rate of a fluid, a valve body is displaced using an electromagnet device including a pair of magnetically coupled coils. The valve opening degree of the valve means is adjusted to a desired valve opening degree by performing duty control of the switching means of each coil with a control signal having a duty ratio corresponding to the valve opening degree indicated by the instruction signal from the opening degree determining means. can do. The first and second circuits for switching between excitation and demagnetization of each coil include first and second coils, and first and second switching means of the electromagnet apparatus, and first and second comparison means. And first and second failure determination means are respectively attached. Thus, for example, even when the mutual inductance between the first and second coils is large, the presence or absence of the above-described disconnection of the first circuit and the second circuit and the location of the failure can be determined by the operation described in claim 1. It can be determined individually. As a specific method of this failure determination method, the methods of claims 2 to 7 can be used.

Further, in the present invention, the fluid is intake air supplied to an internal combustion engine, and the fluid path is associated with an intake pipe for supplying air to the internal combustion engine, and the fluid path is a throttle of the intake pipe. It is a bypass pipe that bypasses the valve mounting position. According to the present invention, the above-described flow control device is attached to, for example, the above-described bypass pipe of the internal combustion engine, and is used as a flow control valve of intake air for controlling the rotation speed of the internal combustion engine in a so-called idle state. When this flow control device is mounted on a vehicle, the size of the electromagnet device is required to be small because the installation place of the flow control device is small. Therefore, a continuous core material for winding the first and second coils is required. Often realized with a book bar. For this reason, the mutual inductance between the first and second coils tends to increase. For this reason, in the above-described flow control device, when the above-described failure occurs only in the circuit including one of the coils and the circuit including the other coil operates normally, the electromotive force caused by the above-described mutual induction causes the occurrence of the above-described failure. There is a large possibility that the electric signal at the connection point fluctuates. In the prior art device, it was only determined whether or not the level of the electric signal crossed the comparison level of the comparison means. Therefore, it was difficult to detect a failure when the mutual inductance was large. In the device described above, a failure can be determined even when the mutual inductance is large, as described in claim 1.

Further, according to the present invention, a display means for displaying that at least one of the first and second power supply paths has a failure, and at least one of the first and second failure determination means determines that there is a failure. When the second failure determination means determines that there is a failure, the internal combustion engine control means reduces the torque of the internal combustion engine when the second failure determination means determines that there is a failure. . According to the present invention, in the above-described flow control device, the first and second coils of the electromagnet device and the first and second coils of the electromagnet device are provided.
When the above-mentioned failure occurs in the second switching means, a so-called fail-safe operation is performed. Specifically, when the above-described failure occurs in the second circuit including the second coil and the second switching means, only the first coil displaces the valve body, so that the valve opening of the flow control valve is determined by the opening determining means. Is larger than the desired valve opening determined by When the flow control device is, for example, a control device of a flow control valve for controlling an idle state of the internal combustion engine for a vehicle, the rotation speed of the internal combustion engine increases to be equal to or higher than the idle rotation speed when the above-described state is continued. As a result, an inconvenience such as a blow-up occurs in the internal combustion engine. For this reason, the internal combustion engine control means shifts the ignition timing of the air-fuel mixture of the internal combustion engine in the retard direction, for example,
The torque of the internal combustion engine is reduced, and the driver is informed that there is a failure using the display means. Also, the first
When the above-described failure occurs in the first circuit including the coil and the first switching means, only the second coil displaces the valve body, so that the valve opening of the flow control valve is determined by the desired valve opening determined by the opening determining means. Less than a degree. For this reason, since the operating state of the internal combustion engine naturally changes in the direction in which the torque decreases, the internal combustion engine control means indicates to the driver only that there is a failure by the display means. Thus, when the above-described flow control device is used for a flow control valve of an internal combustion engine for a vehicle, a failure such as a blow-up of the internal combustion engine may occur due to a failure of the first and second circuits including the electromagnet device. Can be prevented.

Further, the present invention provides a fuel injection valve whose valve body is displaced to supply fuel to an internal combustion engine, a fuel injection amount determining means for deriving an instruction signal indicating a fuel flow rate from the fuel injection valve, and a magnetic coupling. An electromagnetic device for displacing the valve body in a direction in which the valve opening increases, and wherein the second coil displaces the valve body in a direction in which the valve opening decreases. A first switching means connected in series to the first coil, the first coil is excited when in a conductive state, and the first coil is demagnetized in a cut-off state; and A second switching means for energizing the second coil and deenergizing the second coil when the second coil is in a cut-off state; and a duty ratio corresponding to a valve opening corresponding to a fuel flow rate in response to an instruction signal from the fuel injection amount determining means. Are mutually determined Generating first and second control signals, a first control signal for turning on / off the first switching means, and a second control signal for turning on / off the second switching means; The first and second switching means have a first period in which the first switching means is in a conducting state and the second switching means is in a blocking state, and a second period in which the first switching means is in a blocking state and the second switching means is in a conducting state. Signal generating means for duty-controlling the first and second switching means;
A first comparing means for discriminating a signal level of the first electric signal at a first connection point with the switching means at a predetermined discrimination level, and a signal level of the first electric signal in response to an output from the first comparing means. By comparing the change pattern with the change pattern of the signal level of the first control signal, the first coil including the first coil and the first switching means is provided.
First failure determining means for determining a failure in the power supply path, and second comparing means for level discriminating a signal level of a second electric signal at a second connection point between the second coil and the second switching means at a predetermined discrimination level. And responding to the output from the second comparing means, by comparing the change timing of the signal level of the second electric signal with the change timing of the signal level of the second control signal, thereby obtaining the second coil and the second switching means. To determine the failure of the second power supply path including
A fuel injection device for an internal combustion engine, comprising: a failure determination unit. According to the present invention, in a fuel injection device including a fuel injection valve of an internal combustion engine, a valve body is displaced using an electromagnet device including a pair of coils that are magnetically coupled. The valve opening of the fuel injection valve is controlled by a duty ratio control signal corresponding to the amount of fuel injection to be supplied to the internal combustion engine to control the switching means of each coil to obtain a desired valve corresponding to the operating state of the internal combustion engine. The opening can be adjusted. The first and second circuits for switching between excitation and demagnetization of each coil include first and second coils, and first and second switching means of the electromagnet apparatus, and first and second comparison means. And first and second failure determination means are respectively attached. Thus, the first and second circuits can individually determine the presence or absence of the above-described failure and the location of the failure by the operation described in claim 1.
Specific examples of the failure determination method include:
Can be used. When the internal combustion engine including the fuel injection device is mounted on a vehicle, the installation location of the fuel injection device is small, so that the size of the electromagnet device is required to be reduced. Therefore, a core material for winding the first and second coils is required. Is often realized by one continuous bar. For this reason, the mutual inductance between the first and second coils increases. Therefore, when the above-described failure occurs only in the circuit including one coil and the circuit including the other coil operates normally, the electric signal at one connection point fluctuates due to the electromotive force caused by the mutual induction. In the prior art device, it was only determined whether or not the level of the electric signal crossed the comparison level of the comparison means. Therefore, it was difficult to detect a failure when the mutual inductance was large. In the device described in claim 1, as described in claim 1,
Even when the mutual inductance is large, a failure can be determined. [Detailed description of the invention]

FIG. 1 is a block diagram showing an electrical configuration of a flow control device 11 including a failure determination device for an electromagnet device according to a first embodiment of the present invention. The flow control device 11 is a device for adjusting an intake air amount to the internal combustion engine 24 when the idle state of the internal combustion engine 24 is maintained. The internal combustion engine 24 is mounted on, for example, a vehicle. The flow control device 11 includes a flow control valve 13, an electromagnet device 17, switching circuits 19 and 20, a signal generation circuit 22, a NOT circuit 26, comparison circuits 27 and 29, and failure determination circuits 28 and 30.

The flow control valve 13 is interposed in a bypass line 14 attached to the intake line 101 for supplying intake air to the internal combustion engine 24. The bypass line 14 is connected to the suction line 101.
The throttle valve 102 is attached to the suction pipe 101 so as to bypass the upstream and downstream portions of the air flow of the throttle valve 102. In FIG. 1, the direction of the air flow is indicated by an arrow 105.
The valve element 15 of the flow control valve 13 is installed inside the bypass pipe 14. In the suction line 101, a throttle valve 102
The fuel injection valve 103 is attached to a portion between the attachment position 14a of the bypass pipe 14 on the downstream side of the air flow and the intake valve of the cylinder of the internal combustion engine 24. The internal combustion engine 24 is generated by mixing the intake air passing through the intake pipe 101 and the bypass pipe 14 and the fuel injected from the fuel injection valve 103 near the mounting position of the fuel injection valve 103 in the intake pipe 101. Is introduced into the combustion chamber of the cylinder and burned.

When the flow control valve 13 maintains a minimum valve opening such that the throttle valve 102 of the suction line 101 is fully closed in order to keep the internal combustion engine 24 in an idle state,
The flow rate of the intake air passing through the bypass pipe 15 is changed according to a minute change in the operation state of the internal combustion engine 24. Also,
When the internal combustion engine 24 maintains a loaded state such that the vehicle is running, the flow control valve 13 is completely closed, and the amount of intake air to the internal combustion engine 24 is reduced by the accelerator pedal 10.
7 is controlled only by the throttle valve 102 that operates in conjunction with the throttle valve 7. The opening degree of the throttle valve 102 corresponds to, for example, the amount of depression of an accelerator pedal 107. The specific structure and operation of the flow control valve 13 will be described later.

The electromagnet device 17 includes coils L11 and L12.
And at least one pair of electromagnetic solenoids each including The coils L11 and L12 are wound around a single iron core and are magnetically coupled, and the mutual inductance between the coils L11 and L12 is large. The electromagnetic solenoid including the coil L11 increases the valve opening of the flow control valve 13 in a direction in which
The valve body 15 is displaced. The electromagnetic solenoid including the coil L12 displaces the valve body 15 in a direction in which the valve opening of the flow control valve 13 decreases. The detailed structure and operation of the electromagnet device 17 will be described later.

One terminal of each of the coils L11 and L12 is individually connected to a power supply line 18 to which power of + B is supplied. The other terminals of the coils L11 and L12 are grounded via switching circuits 19 and 20, respectively. Coil L1
1 and the switching circuit 19 form a first circuit described later, and the coil L12 and the switching circuit 20 form a second circuit described later. The switching circuits 19 and 20 are controlled by the signal generation circuit 22 in the control circuit 21 as described later. The control circuit 21 includes a plurality of circuits described below,
For example, it is realized by a microcomputer. The plurality of circuits inside the control circuit 21 are virtual circuits realized by arithmetic processing in the microcomputer. Control circuit 21 may be realized by an electric circuit individually including a plurality of real circuits.

An instruction signal indicating the desired valve opening of the flow control valve 13 is given to the signal generation circuit 22 from the internal combustion engine control circuit 25. The internal combustion engine control circuit 25 has both a plurality of opening determination means and internal combustion engine control means. The desired valve opening of the flow control valve 13 is determined in the internal combustion engine control circuit 25 in accordance with the operating state of the internal combustion engine 24. More specifically, the internal combustion engine control circuit 25 measures the current operating state of the internal combustion engine 24, for example, using a plurality of sensors, for example, the rotational speed. Is determined so as to reduce the difference between the two. In the drawing, the internal combustion engine 24 is expressed as “E / G”, and the internal combustion engine control circuit 25 is expressed as “E / G control”.

The signal generating circuit 22 generates a first control signal described later, which is a rectangular pulse signal having a duty ratio corresponding to a desired valve opening of the flow control valve 13. The first control signal is provided to the switching circuit 19 via the switch SW1. Further, the NOT circuit 26 introduces the first control signal from the signal transmission path on the signal flow upstream side of the changeover switch SW1, inverts the phase of the first control signal, and generates the second control signal. The second control signal is provided to the switching circuit 20 via the switch SW2. Changeover switch SW
1 and SW2 are always kept conductive except when a third failure determination operation described later is performed.

The comparison circuit 27 introduces a first electric signal, which will be described later, from a first connection point P11 between the coil L11 and the switching circuit 19, and compares the signal level of the first electric signal with a predetermined discrimination level Vref. The discrimination is performed to generate a first comparison signal representing the discrimination result. The failure determination circuit 28 in the control circuit 21 introduces the first control signal and the first comparison signal,
The presence or absence of a failure in the first circuit,
And where the failure occurs. The comparison circuit 29
Is a second connection point P between the coil L12 and the switching circuit 20.
The second electric signal is introduced from 12 and the signal level of the second electric signal is discriminated from the above-mentioned discrimination level Vref to generate a second comparison signal representing the discrimination result. The failure determination circuit 30 in the control circuit 21 outputs the second control signal and the second
The comparison signal is introduced, and the presence / absence of a failure in the second circuit and the location of the failure are determined by a failure determination method described later. The first signals respectively introduced into the failure determination circuits 28 and 30
And the second control signal are provided by the changeover switches SW1 and SW1, respectively.
The signal is introduced via a path branched from a signal transmission path upstream of the signal flow from SW2. The determination results of the failure determination circuits 28 and 29 are given to the internal combustion engine control circuit 25.

The internal combustion engine control circuit 25 includes a failure determination circuit 2
When a failure is determined in at least one of the steps 8 and 30, a fail-safe operation described below is performed on the internal combustion engine 24. In this fail-safe operation, for example, the torque of the internal combustion engine 24 is reduced.

Coil L12, switching circuit 20, comparison circuit 2
9 and the detailed structure and behavior of the failure determination circuit 30 are the same as the detailed structure and behavior of the coil L11, the switching circuit 19, the comparison circuit 27, and the failure determination circuit 28, respectively. Therefore, hereinafter, the coil L11 and the circuit 1
9, 27 and 28 will be described as examples, and detailed description of the coil L12 and the circuits 20, 29 and 30 will be omitted.

The following describes each circuit 1 relating to the coil L11.
The detailed electrical structure of 9, 27, 28 will be described.

The switching circuit 19 includes resistors R1 to R3, a transistor T11, and a diode D1. The transistor T11 is realized by a MOS FET. The other terminal of the coil L11 is connected in series with the source terminal of the transistor T11 via the resistor R1. First
The connection point P11 is a connection point between the coil L11 and the resistor R1. The drain terminal of the transistor T11 is grounded. The gate terminal of the transistor T11 is connected in series with the changeover switch SW1 in the control circuit 21 via the resistor R2. The resistor R3 is a switch SW1 of the resistor R2.
And a power supply line 41 to which power of the voltage VCC is supplied. The diode D1 has one terminal on the forward current input side connected to the source terminal of the transistor T11 and the other terminal on the forward current output side having a voltage of +
B power supply line 18.

The transistor T11 is in an on state in which a current can pass when a signal level of a first control signal to be described later supplied to the gate terminal is at a low level, and is in an off state in which the current is interrupted when the signal level is at a high level. . In addition, the voltage + B, V of the power supplied to
CC is set such that the voltage level of the source terminal of the transistor T11 is higher when the transistor T11 is on than when it is off.

The comparison circuit 27 comprises a conductor 43, resistors R4 to R
6 and a comparator 44. Conductor 43
Has one end connected to the first connection point P11 and the other end grounded via a resistor R4. The resistors R5 and R6 are connected in series, and are interposed between the power supply line 45 to which the power of the voltage VR is supplied and the ground line. The comparator 44 is realized by, for example, an operational amplifier. The inverting input terminal of the comparator 44 is connected to a connection point P13 between the conductor 43 and the resistor R4. The non-inverting input terminal of the comparator 44 is connected to resistors R5 and R6.
It is connected to the connection point P14 between them. The voltage VR of the power supply line 45 and the resistance values of the resistors R5 and R6 are connected to the connection point P1.
4 are set to values that divide the voltage between the power supply line 45 and the ground line, respectively, so that the voltage level 4 becomes the predetermined discrimination level Vref.

The comparator 44 compares the signal level of the first electric signal with the discrimination level Vref, and outputs a first comparison signal, which will be described later, indicating the result of the comparison. The first comparison signal is, for example, a rectangular pulse signal, and maintains a low level when the signal level of the first electric signal is equal to or higher than the discrimination level Vref,
The high level is maintained when the signal level is lower than the discrimination level Vref.

The failure determination circuit 29 is an internal circuit of the control circuit 21 and includes a timer 46, a latch detection circuit 47, a disconnection determination circuit 48, and a determination circuit 49. These circuits 46
To 49 may be realized by actual circuits or virtual circuits realized by arithmetic processing of a microcomputer.

The timer 46 includes the comparator 4 of the comparison circuit 27.
4 provides a first comparison signal. The timer 46 is connected to the first
At least one of the duration during which the signal level of the comparison signal maintains the high level and the duration during which the signal level maintains the low level is measured, and a duration signal representing the measured duration is derived.

The latch detection circuit 47 is realized by, for example, an RS flip-flop circuit, and receives a first comparison signal from a comparator 44 of the comparison circuit 27 at an R terminal. Further, a reset signal described later is supplied from the determination circuit 49 to the S terminal of the latch detection circuit 47. The latch detection circuit 47 detects a falling edge of the pulse of the first comparison signal, and derives a latch detection signal, which will be described later, indicating the presence or absence of the falling edge of the pulse from the Q terminal.

The disconnection determination circuit 48 is supplied with the first comparison signal from the comparator 44 of the comparison circuit 27, and determines whether or not the first comparison signal always keeps a low level during a later-described inspection period W30. , And a disconnection detection signal representing the determination result is derived.
Further, the disconnection determination circuit 48 introduces the first comparison signal directly from the first connection point P11, discriminates the signal level of the first electric signal in the inspection period W30 to be described later, and derives a disconnection detection signal indicating the discrimination result. The structure may be as follows.

The determination circuit 49 receives a duration signal from the timer 46, a latch detection signal from the Q terminal of the latch detection circuit 47, and a disconnection detection signal from the disconnection determination circuit 48. Further, a first control signal is given from the signal generation circuit 22 to the determination circuit 49. The determination circuit 49 performs a failure determination operation described later based on the plurality of signals, and derives the determination result to the internal combustion engine control circuit 25.

FIG. 2 shows the bypass line 1 including the flow control valve 13.
5 is a partial external view. The bypass pipe 15 is a first pipe 51
Is a T-shaped pipe having one end connected to the side surface of the second pipe 52 and opened, and the flow control valve 13 is formed at the intersection of the pipes. The other end 53 of the first conduit 51 is attached to the intake conduit of the internal combustion engine so as to open to the air flow upstream from the position where the throttle valve is attached, of the intake conduit of the internal combustion engine.
One end 54 of the second conduit 52 is attached to the intake conduit of the internal combustion engine so as to open to the downstream side of the air flow from the position where the throttle valve is attached.

The valve body 15 of the flow control valve 13 is connected to the first pipe 5
1 is a substantially cylindrical member having an outer diameter substantially the same as the inner diameter of one end thereof, and two cutouts formed parallel to the central axis of the cylinder and partially connected to the side surface thereof. Have.
The valve body 15 is mounted such that the central axis of the cylinder coincides with the central axis of the opening at one end of the first conduit, and can be angularly displaced about the central axis of the cylinder as the center of rotation. The internal space of the first conduit 51 is formed at one end of the second conduit by a space between one notch of the valve body 15 and the inner wall of one end of the first conduit 51 than the valve body 15 of the second conduit. It conducts with the internal space of the portion 56 on the 54 side. Further, the internal space of the portion 57 of the second conduit closer to the other end 55 than the valve element 15 is a space between the other cutout of the valve element 15 and the inner wall of one end of the first conduit 51. Thereby, it is electrically connected to the internal space of the portion 56 of the second conduit.

When the valve body 15 is angularly displaced in the first conduit 51, the directions of the two notches of the valve body 15 are displaced, so that the notch and one end of the first conduit 51 are connected to each other. The cross-sectional area perpendicular to the central axis of the space between changes. As a result, the flow rate of the intake air flowing from the first conduit 51 to the portion 56 and the flow rate of the intake air flowing from the portion 56 to the portion 57 increase or decrease in accordance with the increase or decrease in the sectional area. As a result, the flow rate of the intake air derived from one and other ends 54 and 55 of the second conduit 52 changes.

FIG. 3 is a diagram showing a detailed structure of the electromagnet device 17. The electromagnet device 17 includes coils L11 and L12.
In addition, it includes a displacement member 61, spring members 62 and 63, fixing members 64 and 65, a core member 66, a rod-shaped member 67, and a crank device. Spring members 62 and 63 are attached to both ends of the rod-shaped displacement member 61 in the longitudinal direction, and the spring member 6 is fixed between the fixed members 64 and 65 which are the housing of the electromagnet device 17.
2 and 63 are installed. A pair of coils L11, L
12 are prepared in one or more sets, and each pair of coils L1
It is wound around the core member 66 for every L12. Each of the pair of coils L11 and L12 is such that each of the coils L11 and L12 is near one end and the other end of the displacement member 61 and the displacement member 6
The core members 66 are arranged on concentric circles centered on one central axis, and are installed so that each core member 66 is parallel to the longitudinal direction of the displacement member 61. A rod-shaped member 67 is attached to a side surface of a central portion in the longitudinal direction of the displacement member 61 so as to be capable of angular displacement. This rod-shaped member is connected to a crank device. This crank device angularly displaces the valve element 15 of the flow control valve 13.

When the coils L11 and L12 are individually excited, the displacement member 61 moves as shown by arrows 69 and 70.
The fixing members 64, 6 in the direction along the longitudinal direction of the displacement member 61
5 are respectively displaced. These coils L
When the duty ratio of the first and second control signals is controlled by using the first and second control signals in a manner to be described later, the longitudinal direction of the displacement member 61 between the fixed members 64 and 65 corresponds to the duty ratio of the first and second control signals. The position of the displacement member 61 on the along axis is determined. The parallel motion of the displacement member 61 is transmitted to the crank device via the rod-shaped member 67, converted into a rotational motion in the crank device, and transmitted to the valve body 15. Accordingly, the valve element 15 is angularly displaced by an angular displacement amount corresponding to the parallel movement amount of the displacement member 61, that is, an angular displacement amount corresponding to the duty ratio.

The operation of each circuit during normal operation of the flow control device 11 and the operation of each circuit during abnormal operation will be described below.

As described above, the second circuit, the comparison circuit 29,
The behavior of the failure determination circuit 30 is similar to the behavior of the first circuit, the comparison circuit 27, and the failure determination circuit 28. Instead of the operations corresponding to the first and second control signals,
The only difference is that they operate in response to the second and first control signals, respectively, and the other points are the same. Therefore, in the following description, only the behavior of the first circuit when the second circuit operates normally is described, and the description of the behavior of the second circuit when the first circuit operates normally is omitted.

FIG. 4 is a waveform diagram showing signals derived from the control circuit 21, the first circuit, and the comparison circuit 27 in the flow control device 11.

FIG. 4A is a waveform diagram showing the first control signal derived from the signal generator 22. The first control signal is a rectangular pulse signal having a signal period W11, and FIG.
The waveform shown in (1) is repeated periodically. Single signal period W
11, the signal level of the first control signal is at time t11
To switch from the low level to the high level, maintain the high level from time t11 to time t12, switch from the high level to the low level at time t12, and maintain the low level from the time t12 to time t13. The last time t13 of a certain signal cycle W11 and the first time t1 of the next signal cycle W11
Matches 1. Within the single signal period W11, the ratio of the holding time W12 for keeping the signal level at the high level to the holding time W13 for keeping the signal level at the low level, that is, the duty ratio is determined by the operating state of the internal combustion engine 24,
For example, it is changed every single signal cycle W11.

FIG. 4B is a waveform diagram showing the second control signal derived from the NOT circuit 26. The second control signal has the same signal cycle and level change timing as the first control signal derived at the same operation of the flow control device 11, and only the phase is reversed. Therefore, within the single signal period W11 of the second control signal, the holding time W14 for keeping the signal level low and the holding time W15 for keeping the signal level high are the holding times W12, W1 of the first control signal.
3, respectively.

The behavior of the above-described first circuit including the coil L11 and the switching circuit 19 differs depending on the presence / absence of a failure in the first circuit and the location of the failure when there is a failure. First,
The behavior when there is no failure in the first circuit, that is, the behavior at the time of normal operation will be described below.

During normal operation, the first control signal is:
In the switching circuit 19, the voltage is applied to the gate terminal of the transistor T11 via a circuit including the resistors R2 and R3. As described above, the transistor T11 is turned off when the first control signal is at a high level, and turned on when the first control signal is at a low level. When there is no failure in the flow control device 11, the coil L11 is excited when the transistor T11 is in the on state, and is demagnetized when the transistor T11 is in the off state.

Specifically, when the transistor T11 is on, the power supply line 18 connects the coil L11 and the resistor R
1, and power of a voltage level + B is supplied to a power supply path to a ground line via the transistor T11.
The coil L11 is excited. At this time, the voltage level of the connection point P11 depends on the inductance of the coil L11 and the resistance
And the level VL defined by the resistance value. Conversely, when the transistor T11 is off, the power supply path described above is cut off at the transistor T11. As a result, power supply from the power supply line + B to the power supply path is cut off, and no current flows through the path, so that the coil L11 is demagnetized. At this time, the voltage level at connection point P11 is defined at a predetermined level VH. The level VH is a level obtained by dividing the voltage level defined at the source terminal of the transistor T11 by the applied voltage + B of the power supply line 18 and the forward voltage of the diode D1 by the resistors R1 and R4.
The resistance value of the resistors R1 and R4 is, for example, 0
V and the level VH are determined in advance so as to be 13V. The first electrical signal described above is such a transistor T
The first connection point P1 that changes in response to the switching of the state of No. 11
1 is a signal representing a change with time of the voltage level of FIG.

FIG. 4C shows the normal operation of the first and second circuits, and the first control signal of FIG.
9, the first node appearing at the first connection point P11
It is a waveform diagram showing an electric signal. The first electric signal at the time of normal operation is a signal synchronized with the first control signal. Compared with the first control signal, the signal cycle and the signal level switching timing match, and the phase and level values are different. The signal level of the first electric signal maintains the level VL from time t11 to time t12 within a single signal cycle W11,
The signal level is switched at time t12, and maintains the level VH from time t12 to time t13. The continuation times during which the levels VL and VH are maintained are respectively equal to the holding times W12 and W13 of the first control signal. Such a first electric signal is supplied from the first connection point P11 to the comparator 4 of the comparison circuit 27.
4 given.

In the comparator 44, the signal level of the first electric signal is discriminated by the discrimination level Vref at the connection point P14 to generate and derive a first comparison signal representing the level discrimination result. The discrimination level Vref is a level between the binary levels VH and VL of the first electric signal, and is set to a level closer to the level VL than a middle point between the levels VH and VL, for example, 2.5 V. . The first comparison signal is a binary rectangular pulse signal. When the signal level of the first electric signal is lower than the discrimination level Vref, the first comparison signal keeps a high level, and when the signal level is higher than the discrimination level Vref, it keeps a low level.

FIG. 4 (4) is a waveform diagram showing the first comparison signal from the comparison circuit 27 when the first electric signal of FIG. 4 (3) is given when the first and second circuits operate normally. It is. The first comparison signal at the time of normal operation is a signal synchronized with the first control signal, and the signal cycle, the switching timing of the signal level, and the phase all match the first control signal. Therefore, the durations W18 and W19 of maintaining the high level and the low level in the first comparison signal are respectively the same as the retention times W12 and W13 of the first control signal. The first comparison signal is sent from the comparator 44 to the timer 46, the latch detection circuit 47, and the disconnection detection circuit 48 of the failure determination circuit 38.
And are used in a failure determination method described later.

Next, the behavior of the first circuit when there is a failure in the first circuit and the second circuit operates normally, that is, when the first circuit operates abnormally, will be described.

The first flow rate control device 11 can detect the first
Circuit failures are roughly classified into disconnection of the coil L11 and disconnection and short-circuit of the switching circuit 19. The disconnection of the circuit includes, specifically, a disconnection inside a circuit component constituting each circuit, a disconnection of the circuit due to a missing that the driver forgets to attach the circuit component to the flow control device 11, and a terminal of the circuit component. Disconnection of the circuit due to the poor connection between the
Alternatively, disconnection of a conductor connecting between circuits may be mentioned. Hereinafter, such a failure caused by the disconnection is referred to as a “disconnection failure”. A fault that is a short circuit between circuit components or a short circuit between a circuit component and a power supply line is referred to as a “short circuit fault”. Further, the term “failure” includes both a disconnection failure and a short-circuit failure unless otherwise specified.

First, detailed behaviors of the first circuit and the comparison circuit 27 when the switching circuit 19 is disconnected will be described below.

Specifically, the disconnection failure of the switching circuit 19 is as follows.
This is a disconnection failure of the resistors R1 to R3 and the transistor T11. At the time of the disconnection failure of the diode D1, a surge current is generated in the first circuit, but this does not affect the behavior of the entire flow control device 11, and the flow control device 11 operates normally.

The resistors R1 and R2 and the transistor T1
At the time of the disconnection failure of the gate terminal 1, that is, at the time of the disconnection failure of the signal transmission path of the first control signal, despite the fact that the first control signal of FIG. The signal level applied to the gate terminal of the transistor T11 becomes unstable. At this time, the transistor T11 is fixed to one of the ON state and the OFF state regardless of the first control signal, depending on the signal level of the gate terminal. Further, at the time of a disconnection failure of the source terminal and the drain terminal of the transistor T11 and the resistor R3, that is, at the time of the disconnection failure of the portion closer to the ground line than the first connection point of the first circuit, the state of the transistor T11 is changed to the first control signal. Even if the operation is performed in response to the signal level, the power is cut off at the point where the disconnection occurs, so that the entire first circuit is equivalent to the case where the transistor T11 is fixed to the off state. In this state, when the second circuit including the coil L12 stops operating, the first electric signal should always maintain the level VL.

When the transistor T11 is fixed in the off state and the second circuit including the coil L12 operates normally, the coil L12 is connected to the coil L12 in response to switching between the excitation and demagnetization operations of the coil L12. An induced current that generates a magnetic field that cancels out the magnetic field from the other, that is, an induced current due to mutual induction is generated, and the induced current flows in the first circuit. Since there is no break in the path between the first connection point P11 and the coil L11, the first connection point P1
The voltage level of 1 varies depending on the electromotive force caused by mutual induction. As a result, a level change occurs in the first electric signal although the transistor T11 is fixed in the off state. The amount of this level change is determined by the coil L11,
The larger the mutual inductance of L12, the larger. In the present embodiment, it is assumed that the amount of change in the signal level of the first electric signal due to the mutual inductance of the coils L11 and L12 is the level VH at the maximum and the level VL at the minimum.

FIG. 4 (5) shows a case where the above-mentioned disconnection failure occurs in the above-mentioned switching circuit 19, and the second control signal shown in FIG. FIG. 9 is a waveform diagram illustrating a first electric signal appearing at a first connection point P11 when operating.

At this time, the first electric signal is equal in signal cycle to the first and second control signals. The signal level of the first electric signal instantaneously decreases to the level VL at the time t1, and gradually increases from the level VL to the level Vc1 from the time tl to the time t12 in proportion to the elapse of time. Further, at the time t12, the level instantaneously increases from the level Vc1 to the level VH, and gradually decreases from the level VH to the time t13 between the time t12 and the time t13.
To reach the level Vc2. Levels Vc1 and Vc2 are levels between levels VL and VH, and are discrimination levels Vref.
Each larger than.

As described above, at the time of the disconnection failure of the switching circuit 19, the first electric signal is supplied with the level switching timing of the second control signal, that is, the level switching timing t of the first control signal.
The level suddenly changes from 11 to t13, and the level gradually changes during the holding time W12, W13; W14, W15 in which the first and second control signals respectively hold the high level or the low level. Therefore, the signal level of the first electric signal decreases from the level equal to or higher than the discrimination level Vref to the level lower than the discrimination level Vref at the time t11, and is discriminated at the time t14 in the holding periods W12 and W14 and before the time t12. The level increases from a level lower than the level Vref to a level higher than the discrimination level Vref. Thereafter, a certain signal level increases from a level lower than the discrimination level Vref to a level higher than the discrimination level Vref, or a certain signal level decreases from a level higher than the discrimination level Vref to a level lower than the discrimination level Vref. ,
This is referred to as "the signal level crosses the discrimination level."

FIG. 4 (6) shows a state where the first electric signal shown in FIG. 4 (5) is given when the first electric signal shown in FIG. It is a waveform diagram showing. As described above, the signal level of the first electric signal crosses the discrimination level at times t11 and t14. For this reason, the signal level of the first comparison signal switches from the low level to the high level at the time t11, and from the time t11 to the time t11.
14, the high level is switched from the high level to the low level at time t14, and the low level is maintained from time t14 to time t13 through time t12. Therefore, the high-level duration W23 of the first comparison signal when the switching circuit 19 is disconnected has a high-level duration W1 during normal operation.
Shorter than 8. In addition, when the disconnection failure of the switching circuit 19 occurs, the first
The low-level duration W24 of the comparison signal is longer than the low-level duration W19 during normal operation.

Subsequently, the first operation at the time of disconnection failure of the coil L11 is performed.
The detailed behavior of the circuit and the comparison circuit 27 will be described below.

The disconnection failure of the coil L11 is, specifically,
Conductor inside coil L11, coil L11 and power supply line 1
8 and the connection conductor between the coil L11 and the resistor R1 of the switching circuit 19 are broken. At the time of disconnection failure of these conductors, FIG.
Even if the transistor T11 in the switching circuit 19 operates normally in response to the (1) first control signal, power is not supplied to the first circuit. In addition, even when there is mutual induction between the coils L11 and L12, since the above-described conductor is disconnected, no induced current flows through the first connection point P11.

At this time, the voltage level of the first connection point P11 is defined by the voltage level of the source terminal of the transistor T11 and the resistors R1 and R4. Therefore, the first electric signal at the first connection point P11 at the time of the disconnection failure of the coil L11 has a single signal period W11 as shown in FIG.
During this time, the level VL is always maintained. Therefore, when the first potential signal shown in FIG. 4 (7) is given at the time of the disconnection failure of the coil L11, the first comparison signal derived from the comparison circuit 19 is simply output as shown in FIG. The high level is always maintained during one signal cycle W11.

Subsequently, the first operation performed when the short-circuit failure of the switching circuit 19 occurs.
The detailed behavior of the circuit and the comparison circuit 27 will be described below.

The short-circuit fault of the switching circuit 19 is, specifically,
Between the resistors R1 and R2, between both terminals of the diode D1, between the gate terminal of the transistor T11 and the power supply line 41, between the gate terminal and the ground line, between the drain terminal of the transistor T11 and the power supply line 18, and There is a short circuit fault between the drain terminal and the ground line. Resistance R
In the event of a short circuit between R2 and R3, the current flowing through the switching circuit 19 increases, but the behavior of the flow control device 11 is not affected, and the device 11 operates normally.

The transistor T1 is connected between the resistor R1 and the resistor R2.
1 between the gate terminal and the power supply line 41 and between the drain terminal and the ground line.
Although the first control signal shown in FIG. 4A is supplied from 6 to the switching circuit 19, the transistor T11 is always fixed to the ON state. For this reason, the coil L11 is always excited and keeps driving the valve body 15 in the direction in which the valve opening increases. At this time, during the single signal period W11, the first electric signal always keeps the level VH, and the first comparison signal always keeps the low level.

In the event of a short circuit between the drain terminal of the transistor T11 and the power supply line 18 and between the two terminals of the diode D1, the signal generation circuit 46 switches to the switching circuit 19 as shown in FIG.
Despite the application of the first control signal of (1), the transistor T11 is always fixed to the off state. Therefore, the coil L11 is always demagnetized. At this time, the first electric signal is always at the level VL during the single signal cycle W11.
, And the first comparison signal always keeps the high level.

Further, when a short-circuit fault occurs between the gate terminal of transistor T11 and the ground line, that is, when a short-circuit fault occurs in the signal transmission path of the first control signal, the signal generation circuit 46 sends the first circuit of FIG. Despite the application of the control signal, the OFF state is fixed independently of the first control signal. At this time, coil L11, coil L11,
Due to the mutual induction between L12, the signal level of the first electric signal fluctuates as shown in FIG.

As described above, the signal level of the first comparison signal fluctuates in synchronization with the first control signal when there is no failure in the first circuit, and does not synchronize when there is a failure. When three types of failures occur in the first circuit, the comparison circuit 2
7 is supplied with the first electric signal of FIG. 4 (5) due to mutual induction, and FIG. 4 (7) not synchronized with the first control signal.
It can be seen that there are two patterns, that is, when either the first electric signal or the first electric signal maintaining the level VH is applied.

The operation of judging the failure of the first circuit and the second circuit in the flow control device 11 will be described in detail below.

The failure determination circuit 2 of the flow control device 11 described above.
8 and 30 individually determine the presence or absence of a failure in the first and second circuits and the location of the failure based on the difference in behavior between the comparison signal and the control signal. Specifically, the comparison signal is compared with the control signal, and when the change patterns of the signal levels of both signals match, it is determined that there is no failure, and when they do not match, it is determined that there is a failure. When there is a failure in the first circuit and the second circuit, the above-mentioned failure location is determined from the behavior of the comparison signal. This failure determination method includes the following three types of methods according to the behavior of the control signal and the parameter for comparing the change patterns. Further, the failure determination method of the failure determination circuit 30 for the second circuit is similar to the failure determination method of the failure determination circuit 28 for the first circuit, and instead of comparing the first comparison signal and the first control signal. Another difference is that the second comparison signal and the second control signal are compared.

First, a first failure determination method using the timer 46 will be described below.

In the first failure determination method, the failure determination circuit 2
Reference numerals 8 and 30 denote high-level durations Wa and Wb of the first and second comparison signals and the high-level durations of the first and second control signals as parameters for comparing the change patterns of the signal levels of the control signal and the comparison signal. High level holding time W12,
Used with W15. Further, the low-level durations of the first and second comparison signals and the low-level holding times W13 and W14 of the first and second control signals may be used.

The continuation times Wa and Wb are determined by the timers 46 and 62.
Are timed respectively. More specifically, the timers 46 and 62 have, for example, detection means for detecting the rise and fall of the pulses of the first and second comparison signals, and when the detection means detects the rise of the pulse, the durations Wa and
The timer operation of Wb is started, and when the detecting means detects the falling of the pulse, the timer operation is stopped. Thus, timer 4
6, 62, when the first and second comparison signals each have at least one pulse, time durations Wa and Wb, which are pulse widths of the pulse.

The first circuit including the coil L11 and the switching circuit 19
Taking the circuit as an example, when the first circuit and the second circuit operate normally, the duration Wa is determined from FIGS. 4A and 4B.
Is the duration W18, and it can be seen that the duration Wa matches the holding time W12 of the first control signal. 4A and 4B, when the second circuit is operating normally and the switching circuit 19 is broken, the duration Wa is the duration W23, and the duration Wa and the holding time W12 are equal to each other. It turns out that they do not match. Furthermore, at the time of a short-circuit failure of the switching circuit 19 and a disconnection failure of the coil L11, FIG.
From (1) and (8), it can be seen that there is no pulse in the first comparison signal. In this case, the detection means of the timer 46 does not detect the rising and falling of the pulse, so that the timer 46 does not time. At this time, the duration time Wa is
The initial value of the timer 46 is 0 second.

FIG. 5 shows the signal generation circuit 22 of the control circuit 21.
4 is a flowchart for explaining a first failure determination method of a first circuit performed by a failure determination circuit.

When the operation of maintaining the idle state of the internal combustion engine 24 is started, the process proceeds from step a1 to step a2.
In step a2, the signal generation circuit 22 refers to the desired valve opening of the flow control valve 13 provided from the internal combustion engine control circuit 25, and calculates and obtains a duty ratio corresponding to the desired valve opening.

Next, at step a3, the signal generation circuit 2
2 generates a first control signal whose signal level changes at the determined duty ratio,
It is given to the circuit 26. When the first control signal is supplied, the NOT circuit 26 inverts the phase of the first control signal to generate a second control signal, and supplies the second control signal to the switching circuit 20. It is assumed that the first and second control signals are signals having the duty ratios shown in FIGS. 4A and 4B. Thereby, the above-mentioned coil L1
1, L12 repeats a behavior in which one coil is excited and the other coil is demagnetized by alternately switching the coils to be excited. At this time, the first circuit derives any one of the first electric signals in FIGS. 4 (3) and (5) to the comparison circuit 27 in accordance with the presence or absence of the failure. The comparison circuit 27
The first comparison signal shown in FIG. 4 (4) or (6) is derived to the timer 46 of the failure determination circuit 28.

Next, in step a4, the timer 46 of the failure determination circuit 28 measures the high-level duration Wa of the first comparison signal by the above-described method. This duration Wa
Is given to the determination circuit 49 as a duration signal.
Subsequently, in step a5, the determination circuit 49 determines whether the high-level duration time Wa of the first comparison signal matches the high-level holding time W12 of the first control signal. The holding time W12 of the first control signal is obtained directly from the first control signal. Further, the holding time W12 of the first control signal may be obtained from the duty ratio of the first control signal calculated in the signal generation circuit 22 in step a2.

In step a5, the process proceeds from step a5 to step a6 only when the duration time Wa matches the holding time W12, and it is determined that the first circuit has no failure and is operating normally. Further, the duration time Wa is equal to the holding time W1.
If not equal to 2, the process proceeds from step a5 to step a7, where it is determined that the first circuit has a failure and is in abnormal operation. In steps a6 and a7, the determination circuit 49 sets the first
A determination signal representing the determination result of the presence / absence of a circuit failure is generated, and is derived to the internal combustion engine control circuit 25. In step a7, the determination circuit 49 may perform a failure location determination operation described below for a so-called diagnosis operation. After the derivation of the determination signal, if the operation is normal, the process returns from step a6 to step a2, and the failure determination operation is continued. When the operation is abnormal, the process proceeds from step a7 to step a8, and the processing operation of the flowchart ends.

The method of the above-described first circuit fault location determining operation will be described below. This failure location determination method is individually performed for the first circuit using the above-described duration Wa. As described above, when the fault location in the first circuit is different, the behavior of the signal level change of the first comparison signal from the comparison circuit 27 is different, so that the value of the high-level duration Wa is different. Specifically, when the switching circuit 19 has a disconnection failure, the duration Wa is the time W23, and when the coil L11 has a disconnection failure and the switching circuit 19 has a short-circuit failure, the duration Wa is
Is time 0 seconds. Therefore, by determining the length of the duration Wa, it is possible to determine the failure location of the first circuit from the duration Wa.

FIG. 6 is a flow chart for explaining the above-mentioned fault location judging method. In step a5 to step a7 in the flowchart of FIG.
The process proceeds from step 1 to step c2.

At step c2, it is determined whether or not the duration Wa is less than the duration W23 at the time of the disconnection failure of the switching circuit 19 and is equal to or longer than a predetermined time equal to or more than the duration at the time of the disconnection failure of the coil L11. . In the present embodiment, specifically, it is determined whether or not the duration Wa matches the time 0 second. If they match, the process proceeds from step c2 to step c3, where it is determined that the failure of the first circuit is a disconnection failure of the coil L11 or a short-circuit failure of the switching circuit 19. If they do not match, the process proceeds from step c2 to step c4,
It is determined that the failure of the first circuit is a disconnection failure of the switching circuit 19. In steps c3 and c4, the determined failure location and failure reason are stored in, for example, a memory provided in the determination circuit 49. When the above-described determination operation is completed, the process proceeds from Steps c3 and c4 to Step c5, and the processing operation of the flowchart is ended.

Thus, when there is a failure in the first circuit, the location and reason for the failure can be determined from the duration Wa of the comparison signal from the timer 46. Further, if the failure location and the failure reason are stored in the memory, when repairing the flow control device 11 after the failure, the failure location and the failure reason can be known only by reading the stored contents of the memory. Therefore, it is possible to omit the operation of operating the flow control device 11 again at the time of repair to determine the failure location and the reason for the failure, thereby eliminating troublesome failure determination at the time of repair.

The first failure judgment method of the second circuit is different from the first failure judgment method of the first circuit only in that the duration Wa and the holding time W12 are replaced with the duration Wb and the holding time W15. However, since the other behaviors are the same, the description is omitted. The holding time W15 of the second control signal is
It may be directly obtained from the second control signal introduced to the determination circuit 63, or the low-level holding time W1 of the first control signal.
3 and may be obtained from the duty ratio of the first control signal. Further, the fault location determination method of the second circuit is also different from the failure location determination method of the first circuit.
The only difference is that the continuation time Wa and the holding time W12 are replaced by the continuation time Wb and the holding time W15, and the other behaviors are the same.

The first failure determination operation of the first circuit and the second circuit in such a method is performed by the control circuit 21 in parallel, for example. This makes it possible to individually determine whether or not the first circuit and the second circuit of the flow control device 11 have a failure by using the timers 46 and 62.

The internal combustion engine control circuit 25 includes
In response to the determination signals from the control units 9 and 63, the flow control device 11
It is determined whether or not there is a total failure. Only when the judgment signals from both judgment circuits 49 and 63 both indicate that there is no failure, both the first circuit and the second circuit have no failure.
The internal combustion engine control circuit 25 determines that the flow control device 11 is operating normally. When the flow control device 11 operates normally, the valve opening of the flow control valve 13 is controlled to a desired valve opening from the internal combustion engine control circuit 25. At this time, the internal combustion engine control circuit 25 continues to maintain the idle state of the internal combustion engine 24.

Conversely, when at least one of the judgment signals from the judgment circuits 49 and 63 indicates that there is a fault, at least one of the first circuit and the second circuit has a fault. The internal combustion engine control device 25 determines that the flow control device 11 may operate abnormally. When the flow control device 11 operates abnormally, the valve opening of the flow control valve 13 increases or decreases more than the desired valve opening from the internal combustion engine control circuit 25, so that the internal combustion engine 24 can maintain the idle state. It becomes difficult. At this time,
The internal combustion engine control circuit 25 performs a fail-safe operation to reduce the torque of the internal combustion engine 24.

The fail-safe operation of the flow control device 11 at the time of abnormal operation will be described below.

The above-described internal combustion engine 24 includes the flow control device 11
When a failure occurs, the behavior after the failure differs depending on which of the first circuit and the second circuit fails. For example, the first circuit circuit including the coil L11 for displacing the valve body of the flow control valve 13 in the direction to increase the valve opening normally operates, and the coil L for displacing the valve body 15 in the direction to decrease the valve opening.
When only the second circuit, including the circuit 12, fails, the electromagnet device 1
7 displaces the valve body 15 only in the direction in which the valve opening of the flow control valve 13 increases. Therefore, if the internal combustion engine 24 and the flow control device 11 are continuously operated, the flow control valve 13
Is greater than the desired valve opening, for example, the predetermined maximum valve opening of the flow control valve 13. At this time, a blow-up called overrun occurs in the internal combustion engine 24, and the internal combustion engine 24 may not be able to maintain an idle state. On the contrary, when only the first circuit fails and the second circuit operates normally, the electromagnet device 17 is connected to the flow control valve 13.
Since the valve body 15 is displaced only in the direction in which the valve opening decreases, the valve opening of the flow control valve 13 becomes smaller than the desired valve opening if the operation is continued as it is. It becomes the valve opening. At this time, the rotation speed of the internal combustion engine 24 may decrease gradually and stop. From these facts, the internal combustion engine control circuit 25 performs a fail-safe operation corresponding to the faulty circuit in the flow control device 11.

FIG. 7 is a flowchart for explaining the above-mentioned fail-safe operation. Internal combustion engine control device 2
If it is determined that any of the first circuit and the second circuit has a failure in the above-described failure determination operation of the flow control device 11 in step 5, the process proceeds from step b1 to step b2.

In step b2, of the first circuit and the second circuit, a circuit including a coil for displacing the valve element 15 in a direction to decrease the valve opening of the flow control valve 13; in this embodiment, the second circuit fails. It is determined whether or not. More specifically, the determination operation is to determine which of the determination circuits 49 and 63 indicates that there is a failure in response to the determination signals from the determination circuits 49 and 63 described above. Will be implemented. When only the second circuit fails or when both the first circuit and the second circuit fail, the process proceeds from step b2 to step b3, and when only the first circuit fails, the process proceeds from step b2 to step b4.

In step b3, the internal combustion engine control circuit 25
Controls the operating state of the internal combustion engine 24 so that the torque of the internal combustion engine 24 is reduced. Specifically, the internal combustion engine control circuit 25 sets the ignition timing for the air-fuel mixture in the internal combustion engine 24 to a predetermined maximum delay from the basic ignition timing corresponding to the idle state, regardless of the current operating state of the internal combustion engine 24. The angle is retarded by the angle value. As a result, the rotation speed of the internal combustion engine 24 becomes lower than the idle rotation speed corresponding to the idle state, and the torque decreases. Therefore, the internal combustion engine 24 finally stops. Further, the internal combustion engine control circuit 25 turns on a warning light, for example, installed on an instrument panel of the vehicle, to indicate to the occupant of the vehicle that the flow control device 11 has a failure.

At step b4, the internal combustion engine control circuit 25 turns on the above-mentioned warning light to
1 is indicated to the occupant of the vehicle that there is a failure. When the processing operations in steps b3 and b4 are completed, step b
Steps b3 and b4 proceed to step b5, respectively, and the processing operation of the flowchart ends.

Thus, when the second circuit of the flow control device 11 fails, the internal combustion engine 24 can be prevented from operating beyond the idle state. Therefore, it is possible to prevent the inconvenience of the internal combustion engine 24 from rising and the vehicle from suddenly starting. Also,
At the time of failure of either the first circuit or the second circuit, the fact that there is a failure in the flow control device 11 can be presented to the occupant.

Next, the second failure determination method will be described in detail below.

In the second failure determination method, the failure determination circuit 2
8, 30 use the falling and rising timings of the pulses of the first and second comparison signals in the single signal period W11 as parameters for comparing the change patterns of the signal levels of the control signal and the comparison signal.

The first including the coil L11 and the switching circuit 19
Taking the circuit as an example, during normal operation of the first and second circuits, as shown in FIGS. 4A and 4B, the falling timing of the pulse of the first comparison signal is determined by the falling timing of the pulse of the first control signal. This coincides with time t12, which is the fall timing. Further, when the second circuit operates normally, the switching circuit 19
In the event of a disconnection failure, as shown in FIGS. 4 (1) and (6),
Time t14, which is the fall timing of the pulse of the first comparison signal, is earlier than time t12 described above. Furthermore,
At the time of the disconnection failure of the coil L11, as shown in FIGS. 4 (1) and (8), the first comparison signal always keeps the high level, so that the pulse does not fall. As described above, the timing of changing the signal level of the first comparison signal differs between the normal operation and the failure. In the second failure determination method, the difference in the change timing is determined by the determination period W26 near time t12.
It is detected from the presence or absence of the falling edge of the pulse within.

The determination period W26 is a period from time t15, which is a timing which is traced back from the pulse fall timing of the first control signal by the backward traveling time W27, to time t13, which is the end timing of the signal cycle W11. The backward traveling time W27 is such that the time t15, which is the start timing of the determination period W26, is later on the time axis than the time t14, which is the fall timing of the pulse of the first comparison signal at the time of the disconnection failure of the switching circuit 27. Is set to

The backward traveling time W27 is determined each time the duty ratio is changed, for example, corresponding to the duty ratio of the first control signal. Further, the backward traveling time W27 may be a fixed time experimentally determined so as to satisfy the above-described condition. The fixed backward traveling time W27 is determined so as to satisfy the above-described condition when, for example, the duty ratio of the first control signal is minimum. Thus, the fixed backward travel time W27
Is determined, the time t15 becomes a timing later on the time axis than the time t14 even when the duty ratio increases from the minimum duty ratio. In the following description, it is assumed that the backward traveling time W27 is a fixed time.

The falling timing of the pulse of the first comparison signal is detected by the latch detection circuit 47.
The latch detection circuit 47 is realized by a flip-flop circuit as described above. The latch detection signal from the Q terminal of the latch detection circuit 47 is a binary signal that takes one of values 0 and 1, and is 0 in an initial state. When the pulse of the first control signal supplied to the R terminal has a falling edge, the latch detection circuit 47 in the initial state is set to the set state, and the value of the latch detection signal becomes “1”. Switching of the latch detection circuit 47 from the initial state to the set state is performed as a mechanical operation of the circuit 47 independently of a failure determination operation described later.

FIG. 8 is a flowchart for explaining the above-described second failure determination method for the first circuit.

When the operation of maintaining the idle state of the internal combustion engine is started, the latch detection circuit 47 is returned to the initial state,
The process proceeds from step d1 to step d2. In step d2, the signal generation circuit 22 calculates and calculates the duty ratio of the first control signal. The operation in step d2 is the same as the operation in step a2 of the flowchart in FIG. Next, in steps d3 to d7, the operation of generating the first and second control signals and the operation of detecting the falling edge of the pulse are performed in a pseudo parallel manner. The operation of generating the first and second control signals is the same as the operation of step a3 in the flowchart of FIG. The above-described switching operation of the latch detection circuit 47 from the initial state to the set state is performed independently of the processing operation during the execution of the processing operations of steps d3 to d7.

Specifically, first, at time t11, the process proceeds to step d3, and as a first control signal generation operation, the signal generation circuit 22 switches the signal level of the first control signal being derived from a low level to a high level. . by this,
The signal level of the second control signal from the NOT circuit 26 is switched from high level to low level. Hereinafter, in the drawings, the first control signal is “S1” and the second control signal is “S2”.
It expresses.

Subsequently, in step d4, as a falling detection operation, the timer provided in the determination circuit 49 starts counting the time W28 from time t11. The counted time W28 is a time from time t11 to time t15, which is the start timing of the above-described determination period W26, and
It is obtained by subtracting the backward traveling time W27 from the high-level holding time W12 of the control signal. The time t15 is the time t
It is a time that is traced back from W12 by the backward travel time W27, but is determined by clocking the above-described time W28 from time t11 during the actual second failure determination operation. The clocking time W28 is obtained by, for example, determining the holding time W12 from the duty ratio of the first control signal in the determination circuit 49, and further subtracting the backward traveling time W27 from the holding time W12.
When the counting of the counting time W28 is completed and the time t15 is reached, the process proceeds to step d5.

In step d5, the judgment circuit 49 supplies a reset signal such as a binary signal of value 1 to the S terminal of the latch detection circuit 47, and returns the latch detection circuit 47 to the initial state. For example, when the switching circuit 19 of the first circuit breaks, the latch detection circuit 47 is already in the set state, but is returned to the initial state at time t15. Further, when the first circuit and the second circuit operate normally and when the coil L11 has a disconnection failure, the latch detection circuit 27 keeps the initial state at the time t15, so that the initial state is kept as it is. Time t
15 and thereafter, when the first circuit and the second circuit operate normally,
Latch detection circuit 47 switches to the set state at time t12, for example.

Subsequently, at time t12, step d6
Then, as a deriving operation of the first control signal, the signal generation circuit 22 switches the signal level of the first control signal being derived from a high level to a low level. As a result, the signal level of the second control signal from the NOT circuit 26 is switched from a low level to a high level. Further, at time t13, the process proceeds to step d7, where the signal generation circuit 22 outputs
The signal level of the control signal is switched from low level to high level. Thereby, the signal level of the second control signal from the NOT circuit 26 is switched from the high level to the low level. Thus, the derivation of the first and second control signals within the signal cycle W11 started in step d3 ends,
The process proceeds to the derivation of the first and second control signals in the next signal cycle W11. After time t13, the process proceeds to step d8.

At step d8, the judgment circuit 49 judges whether or not the latch detection circuit 47 is in the above-mentioned set state. This determination operation is specifically performed by determining whether the value of the latch detection signal from the Q terminal of the latch detection circuit 47 is “1”. Since the latch detection circuit 47 is once returned to the initial state at time t15,
At the time of the determination in step d8 after time t13, only when the first control signal has a falling edge in the determination period W26, that is, only during normal operation, the latch detection circuit 4
7 is set.

The determination circuit 49 performs the steps d8 to d only when the latch detection circuit 47 is in the set state.
Proceeding to 9, it is determined that there is no failure in the above-described first circuit and normal operation is being performed. When the circuit 47 is in the reset state, the process proceeds from step d8 to step d10, and it is determined that the first circuit has a failure and is in abnormal operation. In steps d9 and d10, the determination circuit 49 generates a determination signal indicating a determination result of the presence or absence of a failure in the first circuit, and derives the determination signal to the internal combustion engine control circuit 25. Step d9,
Each operation of d10 corresponds to step a in the flowchart of FIG.
6 and a7. After the derivation of the determination signal, when the normal operation is being performed, the latch detection circuit 48 is returned to the initial state, the process returns from step d9 to step d2, and the failure determination operation is continued. If the operation is abnormal, the process proceeds from step d10 to step d11, and the processing operation of the flowchart ends. By this series of determination operations, from the falling timing of the pulse of the first comparison signal,
The presence or absence of a failure in the first circuit can be determined.

The second failure determination method of the second circuit is similar to the second failure determination method of the first circuit, and the latch detection circuit 64 detects the rising edge of the pulse of the second comparison signal within the single signal period W11. Is detected, and the other behaviors are the same.

The second failure judging operation of such a method is individually performed in parallel on each of the first circuit and the second circuit. A determination signal is given to the internal combustion engine control circuit 25 from each of the failure determination circuits 28 and 30.
The internal combustion engine control circuit 25 determines the presence or absence of a failure in the flow control device 11 in response to the determination signals from the determination circuits 49 and 63, and determines whether the failure is in the first circuit or the second circuit. And perform a fail-safe operation. The failure determination operation and the fail-safe operation of the flow control device 11 of the internal combustion engine control circuit 25 are performed when the first failure determination method described above is used for the first and second circuits.
Since the failure determination operation and the fail-safe operation described above are the same, the description thereof will be omitted.

By such an operation, it is possible to determine whether or not the first circuit and the second circuit of the flow control device have a failure by using the latch detection circuits 47 and 64.

Next, the third failure determination method will be described in detail below.

In the third failure determination method, the derivation of one of the first and second control signals is temporarily stopped, and the change in the signal level of one of the first and second comparison signals at that time is performed. The presence / absence of a failure is determined by comparing the pattern with a change pattern of one of the first and second control signals. The fall timing of the pulses of the first and second comparison signals is used as a parameter for comparing the change patterns.

FIG. 9 is a waveform diagram for explaining the behavior of each circuit of the flow control device in the third failure determination method.
The behavior of each signal within the single signal period W11 in the waveform diagram of FIG. 9 is the same as the behavior of each signal shown in the waveform diagram of FIG. 4, and the same points are denoted by the same reference numerals and description thereof will be omitted. 9 shows a signal waveform over a plurality of signal periods W11, the duty ratios of the first and second control signals between the plurality of periods shown in FIG. 9 are equal to the first period unless otherwise specified. Assume that The third failure determination method is performed during the fourth signal cycle W11 in the waveform diagram of FIG.

When a failure determination operation using the third failure determination method is performed on the first circuit, the first control signal is set as shown in FIG.
As shown in (2), the low level is always maintained within the inspection period W30. The inspection period W30 is equal to the signal period W11 in the present embodiment. At this time, the signal level of the second control signal changes so as to be a rectangular pulse signal having a duty ratio determined by the signal generation circuit 22, as shown in FIG.

When the first circuit operates normally, the signal level of the first electric signal changes in accordance with the signal level of the first control signal. Therefore, as shown in FIG.
It always keeps high level within 0. Therefore, as shown in FIG. 9D, the signal level of the first comparison signal always keeps the low level within the inspection period W30. Switching circuit 19
When the disconnection fault occurs, the signal level of the first electric signal fluctuates due to the induced current caused by mutual induction between the coils L11 and L12.
As shown by the solid line 71 in FIG. 9 (5), the value fluctuates within the inspection period W30. The behavior of the first electric signal during the inspection period W30 is equal to the behavior of the first electric signal at the time of the disconnection failure of the switching circuit 19 shown in FIG. Therefore, the first comparison signal indicates the inspection period W3 as indicated by the solid line 72 in FIG.
The signal is such that a rectangular pulse is generated within 0. Furthermore, when the coil L11 has a disconnection failure, the signal level of the first electric signal always keeps the low level as shown by the two-dot chain line 73 in FIG. 9 (5). Therefore, the signal level of the first comparison signal always keeps the high level during the inspection period W30 as shown by the two-dot chain line 74 in FIG. 9 (6).

As described above, the behavior of the signal level of the first comparison signal in the inspection period W30 differs between the normal operation and the failure. In the third failure determination method, the difference in the behavior of the level change is detected from the presence / absence of the fall of the pulse in the inspection period W30 and the signal level of the first comparison signal in the inspection period W30.

FIG. 10 is a flow chart for explaining the above-mentioned third failure judgment method of the first circuit. The flowchart of FIG. 10 is similar to the flowchart of FIG. 8, and a detailed description of steps for performing the same operation will be omitted.

When the operation of maintaining the idle state of the internal combustion engine 24 is started, the process proceeds from step e1 to step e2.
In step e2, the signal generation circuit 22 calculates and obtains the duty ratio of the first control signal. The detailed operation of step e2 is the same as the operation of step d2 in the flowchart of FIG. Next, in step e3, the reset signal is supplied to the latch detection circuit 47 to return the latch detection circuit 47 to the initial state. The detailed behavior of the latch detection circuit 47 is equal to the behavior described in the second failure determination method. The operation in step e3 is the same as the operation in step d5 in FIG.

In steps e4 to e6, the first and second
An operation for deriving a control signal is performed. In these steps, the signal generation circuit 22 continues to derive the first control signal, but the determination circuit 49 switches the changeover switch SW1 to the cutoff state, so that the switch circuit 19 is not supplied with the first control signal. Therefore, the transistor T11 of the switching circuit 19 always keeps the off state. Further, the first control signal is supplied to the NOT circuit 26, so that the second control signal is generated. At this time, the judgment circuit 63 keeps the changeover switch SW2 conductive, so that the second control signal is given to the changeover circuit 20. Instead of the combination of the signal generation circuit 22 and the NOT circuit 26 described above, a pair of signal generation circuits such as registers for individually generating the first and second control signals are prepared. Instead of switching states,
The signal generation operation from each signal generation circuit may be individually stopped. Switch SW1 and resistor R2
R3 and the power supply line 41 constitute a forcing means of the first circuit.

More specifically, first, at time t11, the process proceeds to step e4, where the signal generation circuit 22 switches the signal level of the first control signal being derived from a low level to a high level. At the same time, the judgment circuit 49 turns off the changeover switch SW1, and the judgment circuit 63 keeps the changeover switch SW2 conductive. As a result, the signal level of the second control signal applied to the switching circuit 20 is switched from the high level to the low level. Further, the signal level of the first control signal supplied to the switching circuit 19 on the downstream side of the signal flow from the changeover switch SW1 is maintained at a low level regardless of the signal level of the first control signal from the signal generation circuit 22.

Subsequently, at time t12, step e5
The signal generation circuit 22 switches the signal level of the first control signal being derived from a high level to a low level. At this time, the changeover switches SW1 and SW2 are kept in the cut-off state and the conduction state, respectively, so that the first control signal given to the switch circuit 19 is kept at the low level,
Only the signal level of the second control signal given to 0 is switched from the low level to the high level.

Subsequently, at time t13, step e6
The signal generation circuit 22 switches the signal level of the first control signal being derived from a low level to a high level. Since the changeover switch SW2 is kept in a conductive state, the NOT switch
The second control signal from the circuit 26 is directly supplied to the switching circuit 20. In step e6, the changeover switch S
Since W1 is switched to the conductive state, the first control signal from signal generation circuit 22 is supplied to switching circuit 19 thereafter.
Through these series of operations, the first and second control signals in the inspection period W30 as shown in FIGS. 9 (2) and 9 (1) are derived.

Next, at step e7, the judgment circuit 49
, It is determined whether or not the latch detection circuit 47 is in the aforementioned set state. This determination operation is the same as the operation in step d8 of the flowchart in FIG. In the third failure determination method, since the latch detection circuit 47 is temporarily returned to the initial state before the start of the inspection period W30, step d8 is performed.
Is determined only when there is a falling edge of the pulse in the first comparison signal during the inspection period W30, that is, the switching circuit 1
The latch detection circuit 47 is set only at the time of the disconnection failure of No. 9. The determination circuit 49 proceeds from step e7 to step e8 only when the latch detection circuit 47 is in the reset state.

In step e8, the determination circuit 49 determines whether the first comparison signal is in the inspection period W based on the level discrimination result of the signal level of the first comparison signal determined in the disconnection determination circuit 48.
It is determined whether or not the low level is always maintained within 30, that is, whether or not the signal level V of the first electric signal is always lower than the reference level Vref within the inspection period W30.

The above-described determination operation in the disconnection determination circuit 48 may be realized by an operation of directly introducing the first electric signal to newly discriminate a new discrimination level below the reference level. It may be determined whether or not the signal level of the first comparison signal from the controller always keeps the high level. As described above, when the signal level of the first electric signal always keeps the minimum level VL, a disconnection failure of the coil L11 has occurred in the first circuit. Step e8 is performed to detect the disconnection failure of the coil L11.

When the latch detection circuit 47 is in the reset state in step e7 and when the signal level V of the first electric signal is less than the discrimination level Vref in step e8,
Proceeding to step e9, it is determined that there is no failure in the first circuit and that the circuit is operating normally. Further, when the circuit 47 is in the set state or when the signal level of the first electric signal is equal to or higher than the discrimination level, the process proceeds from Steps e7 and e8 to Step e10, respectively.
It is determined that an abnormal operation is being performed. In steps e9 and e10, the determination circuit 49 derives a determination signal representing the determination of the presence or absence of a failure in each circuit to the internal combustion engine control circuit 25. The detailed operations in steps e9 and e10 are the same as those in steps ed9 and d10.

If the normal operation is performed after the derivation of the determination signal, the process returns from step e9 to step e2 to continue the failure determination operation. If the operation is abnormal, the process proceeds from step e10 to step e11, and the processing operation of the flowchart ends. Through this series of determination operations, it is possible to determine the presence or absence of a failure in the first circuit.

The second failure judgment method of the second circuit is similar to the second failure judgment method of the first circuit, and is similar to the second failure judgment method of the first circuit.
The changeover switches SW1 and SW are derived by deriving the signals of 4 to e6.
2 is maintained in a conducting state and a blocking state, respectively;
The difference is that the latch detection circuit 64 detects the rise of the pulse of the second comparison signal within the single signal period W11, and the other behaviors are the same, so the description is omitted.

Such a failure determination operation is performed alternately on each of the first circuit and the second circuit. First
The third failure determination operation of the circuit and the third failure determination operation of the second circuit are alternately performed at predetermined time intervals.
This time interval is determined by the control circuit 2 of the first and second control signals.
By stopping the derivation from 1 respectively, the time interval is set to such an extent that the operation of the flow control valve 13 itself is not affected. This time interval is, for example, two consecutive
The time interval between the third failure determination operations of the first circuit is set to be twice the time interval between the third failure determination operations of the successive first and second circuits. Specifically, a time interval from a certain time of the third failure determination operation of the first circuit to the next time the third failure determination operation of the first circuit is about 20 seconds,
The second failure of a subsequent cycle from the third failure determination operation of the first circuit of one cycle
The time interval until the third failure determination operation of the circuit is about 10 seconds.

The internal combustion engine control circuit 25 is supplied with a determination signal from one of the failure determination circuits 28 and 30 for each third failure determination operation. The internal combustion engine control circuit 25 responds to the determination signals from the respective determination circuits 49 and 63, for example, in response to the two determination circuits 4 provided continuously.
Only when both of the judgment signals from 9 and 63 indicate that there is no failure, it is judged that the flow control device 11 is operating normally. At this time, the internal combustion engine control circuit 25 continues the operation of maintaining the idle state.

When a determination signal indicating that there is a failure is provided from one of the determination circuits 49 and 63, it is determined that the flow control device 11 is operating abnormally.
At this time, the internal combustion engine control circuit 25 performs the same fail-safe operation as the operation shown in the flowchart of FIG.
When these operations are performed, the processing operation of the failure determination operation of the flow control device 11 ends. With such an operation, it is possible to determine whether or not the first circuit and the second circuit of the flow control device have a failure by using the latch detection circuits 47 and 64.

In the third failure judging method, a level discriminating means for the first electric signal is provided instead of detecting the presence or absence of the rising edge of the pulse using the latch detecting circuit 47 in step e7. The determination may be performed by determining whether or not the signal level of one comparison signal becomes equal to or higher than the discrimination level Vref at least once. At this time, when the signal level of the first electric signal becomes equal to or higher than the discrimination level Vref at least once, the determination circuit 46 performs step e.
Proceeding to 10, it is determined that there is a failure and abnormal operation is being performed.
Using this method, the disconnection failure of the switching circuit 19 and the disconnection failure of the coil L11 can be detected simultaneously.

The flow control device 11 of the present embodiment detects the presence or absence of a failure in the first circuit and the second circuit by using at least one of the first to third failure determination methods described above. Therefore, the failure determination circuits 28 and 30 may include only circuits related to the failure determination method to be performed, and may omit the circuit of the failure determination method that is not performed.

Further, the flow control device 11 is provided with the first
A structure for determining the presence or absence of a failure in only one of the circuit and the second circuit may be provided. At that time, only one of the comparison circuits 27 and 29 and the failure determination circuits 28 and 30 is prepared according to the circuit in which the failure is to be detected. For example, in a flow control device having a structure for determining the presence or absence of a failure in only the first circuit, a comparison circuit 27 and a failure determination circuit 28 are prepared, and the comparison circuit 29 and the failure determination circuit 30 are deleted. Conversely, in a flow control device having a structure for determining the presence or absence of a failure in only the second circuit, the comparison circuit 2
9 and the failure determination circuit 30 may be prepared, and the comparison circuit 27 and the failure determination circuit 29 may be deleted.

Further, the electromagnet device 17 of the present invention, and the failure determination device including the switching circuits 19 and 20, the comparison circuits 27 and 29, and the control circuit 21, are provided with a flow control valve 13
It may be attached to other valve devices other than the above. For example, it may be attached to a fuel injection device including a fuel injection valve 103 for supplying fuel to the internal combustion engine 24 described above.

The fuel injection valve 103 of the fuel injection device is, for example, as shown in FIG.
Of these, it is provided in a portion downstream of the throttle valve 102 in the air flow. The structure of the fuel injection valve 103 is similar to the structure of the flow control valve 13 described above, except that a valve element is installed in a fuel supply line 108 connecting the fuel tank and the suction line 101. Have the same structure. Fuel injection valve 1
03 may be a structure that supplies fuel directly into the cylinder of the internal combustion engine 24. This valve body is the same as the above-described electromagnet device 1
7 displaces the same as the valve body 15 of the flow control valve 13. The duty ratios of the first and second control signals for controlling the coils L11 and L12 of the electromagnet device are set so that the air-fuel ratio of the mixed gas sucked into the internal combustion engine 24 becomes the ideal air-fuel ratio. And the ideal operating state. The failure determination operation of the first circuit including the coil L11 and the failure determination operation of the second circuit including the coil L12 are performed by the above-described first to third failure determination methods.

By using this failure determination method, the failure of the electromagnet device 17 can be easily determined. Also,
Due to the failure of the first circuit of the electromagnet device 17, the fuel is injected indefinitely and the air-fuel ratio becomes larger than the ideal air-fuel ratio, so that the contents of carbon monoxide, nitrogen compounds and hydrocarbons in the exhaust gas increase. Thus, it is possible to prevent the catalyst in the discharge pipe from being completely removed.

[0154]

As described above, according to the present invention, the failure determination apparatus for an electromagnet including a pair of coils that are magnetically coupled detects a failure such as a disconnection in a circuit including a coil and a switching element. The failure detection method of this device includes a change pattern of a level discrimination result of a signal level of an electric signal appearing at a connection point between a coil and a switching means, and a change of a signal level of a control signal for conducting and blocking the switching means. The comparison is made with the pattern. Thus, in the failure determination means responding to the output from the comparison means, when the mutual inductance between the pair of coils is large, the disconnection of the coil, the disconnection of the switching means, and the disconnection of the signal transmission path for providing a control signal to the switching means are determined. All can be detected.

Further, according to the present invention, the failure judging means can calculate the first duration of the level of the comparison signal indicating the level discrimination result of the electric signal and the first level changeable level of the first control signal.
The presence or absence of a failure is determined by comparing the holding time of the switching means. As a result, in a device having a large mutual inductance, there is a failure such as disconnection of the first switching means and disconnection of the signal transmission path. , Or vice versa, it can be determined that there is a failure. Further, since this failure determination means only includes a means for measuring the duration of the comparison signal, a means for calculating the holding time from the first control signal, and a means for comparing the duration with the holding time, the circuit configuration is simple. It is easy to implement.

Further, according to the present invention, the above-mentioned failure judging means determines whether the failure location of the device is on the first coil side or the first switching means side with respect to the connection point, depending on the duration. Can be determined. by this,
By simply comparing the continuation time with the two types of reference times, it is possible to determine the presence or absence of a failure and the failure location. In addition, since this failure point determination method can be performed only by comparing the duration time with the reference time, it is easy to add the failure determination means to the above-described failure determination means.

Further, according to the present invention, the failure determination means detects whether or not a predetermined level change of the comparison signal indicating the discrimination result of the signal level of the electric signal has occurred within a predetermined determination period. Determine whether there is a failure. The start time of the timing operation in the determination period is a predetermined time generated in the comparison signal when a failure such as disconnection of the first switching means and disconnection of the signal transmission circuit occurs and mutual inductance between the pair of coils is large. It is set after the time when the level change occurs. Accordingly, it is possible to determine that there is a failure in the above-described case, for example, even when the level of the electric signal fluctuates from the discrimination level to a level lower than the discrimination level or vice versa due to the electromotive force of mutual induction. Further, since this failure determination means can be realized only by means for measuring the determination period and means for detecting a desired level change of the comparison signal, the circuit structure is simple and easy to realize.

Further, according to the present invention, the above-mentioned failure judging means forcibly fixes the first switching means to a conduction state or a cut-off state during a predetermined inspection period, and the above-mentioned comparison signal at this time is output. The presence or absence of a failure is determined by detecting whether or not the level has changed. In this determination method, the signal level of the comparison signal changes only when a failure such as disconnection of the first switching means and disconnection of the signal transmission circuit occurs. Therefore, it is determined from the level change that there is a failure. Can be. Further, since this failure determination method can be realized only by means for stopping the derivation of the control signal, means for measuring the determination period, and means for detecting whether or not the level of the comparison signal has changed, the circuit structure is simple. It is easy to realize.

Further, according to the present invention, the above-mentioned failure judging means forcibly fixes the first switching means to a conduction state or a cut-off state during a predetermined inspection period, and the above-mentioned electric signal at this time is at a level. The presence or absence of a failure is determined by detecting whether or not there has been a change. In this determination method, the first
The signal level of the electric signal changes only when a failure such as disconnection of the switching means and disconnection of the signal transmission circuit occurs. Therefore, it can be determined from the level change that there is a failure. Further, since this failure determination means can be realized only by means for stopping the derivation of the control signal, means for measuring the determination period, and means for discriminating the level of the electric signal, it is easy to realize. Further, since the failure determination method directly determines the level of the electric signal, the circuit for generating the comparison signal can be omitted from the above-described failure determination device, and the circuit structure can be further simplified.

According to the present invention, in addition to the above-described failure determination method during the inspection period, the above-described failure determination means may be configured as follows.
A failure determination operation of the first coil is performed. As a result, all of the three disconnections described above can be detected. Further, the failure determination means of the first coil may discriminate the level of the comparison signal or may directly determine the level of the electric signal. When directly determining the level of the electrical signal in the failure determination operation of the first coil and when used together with the failure determination operation of the first switching means using the above-described electrical signal,
The circuit structure can be simplified by eliminating the comparison signal generation circuit from the above-described failure determination device.

According to the present invention, a flow control device including a valve having a structure in which a valve body is displaced by an electromagnet device having a pair of coils and a fuel injection device for an internal combustion engine use the above-described failure determination device to perform both operations. Failures in circuits including coils are individually detected. Thus, in a device including a flow control valve and a fuel injection valve particularly associated with an internal combustion engine for a vehicle, in which the iron cores of both coils are realized by a single bar for miniaturization, only one of the coils is used. When a failure occurs and the other coil operates normally, the failure of each coil can be reliably determined. In addition, the coil determination method is realized by any of the above-described methods, the number of circuits added for realization is small, and the structure of each circuit is simple, so that the structure of the entire device is simplified.

Further, according to the present invention, when the above-described flow control device is used for controlling the intake air amount of a vehicle, when the coil for displacing the valve body in the direction to decrease the valve opening of the flow control valve fails. The internal combustion engine is controlled so that the torque decreases. Thus, when the above-described coil breaks down, it is possible to prevent a disadvantage such as a blow-up of the internal combustion engine from occurring.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a flow control device 11 including a failure determination device for an electromagnet device 17 according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an appearance of a flow control valve 13.

FIG. 3 is a schematic diagram showing a specific structure of the electromagnet device 17;

FIG. 4 shows first and second control signals output from a control circuit 21 of the flow control device 11, and the flow control device 11
FIG. 6 is a waveform diagram showing a first electric signal and a first comparison signal output from each circuit when the first circuit is operating normally and when it is out of order.

FIG. 5 is a flowchart illustrating a first failure determination method for a first circuit of the flow control device.

FIG. 6 is a flowchart illustrating a method of determining a failure location of a first circuit of the flow control device.

FIG. 7 is a flowchart illustrating a fail-safe operation of the internal combustion engine control device 24.

FIG. 8 is a flowchart for explaining a second failure determination method of the first circuit of the flow control device.

FIG. 9 is a flow chart showing the second and first control signals output from the control circuit 21 of the flow control device 11 and the flow control device 11 in the third failure determination operation of the first circuit of the flow control device;
FIG. 6 is a waveform diagram showing a first electric signal and a first comparison signal output from each circuit when the first circuit is operating normally and when it is out of order.

FIG. 10 is a flowchart illustrating a third failure determination method for the first circuit of the flow control device.

FIG. 11 is a block diagram showing an electrical configuration of a failure determination device 1 for an electromagnet device according to a first prior art.

FIG. 12 is a waveform diagram illustrating first and second control signals output from the failure determination device 1 and a first electric signal output during normal operation and failure from the failure determination device 1 of the failure determination device 1. It is a waveform diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Flow control device 13 Flow control valve 14 Detour line 15 Valve 17 Electromagnet device 19, 20 Switching circuit 22 Signal generation circuit 26 NOT circuit 27, 29 Comparison circuit 28, 30 Failure judgment circuit 46, 62 Timer 47, 64 Latch detection Circuits 48, 65 Disconnection determination circuit 49, 63 Determination circuit 24 Internal combustion engine 25 Internal combustion engine control circuit P11 First connection point P12 Second connection point L11, L12 Coil

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 69/46 G01R 31/00 G01M 17/007 F02M 69/00 380F G01R 31/00 G01M 17/00 K

Claims (11)

[Claims] 1. An electromagnet device having a pair of magnetically coupled first and second coils, connected in series to the first coil, the first coil is excited when in a conductive state, and the first coil is demagnetized in a disconnected state. A second switching means connected in series to the second coil, the second coil being excited when in a conductive state, and the degaussing of the second coil in a cut-off state; and conducting the first switching means. A first control signal for turning on / off and a second control signal for turning on / off the second switching means, wherein the first and second control signals are such that the first switching means is in a conducting state and the second switching means is in a shut off state. The first and second switching means are de-coupled so as to have a first period in which the first switching means is in a cut-off state and a second period in which the second switching means is in a conducting state. Signal generating means for performing duty control, comparing means for level discriminating a signal level of an electric signal at a first connection point between the first coil and the first switching means at a predetermined discrimination level, and responding to an output from the comparing means; Failure determination means for determining a failure by comparing a change pattern of a signal level of an electric signal at a first connection point with a change pattern of a signal level of a first control signal; apparatus. 2. The failure judging means, wherein the comparing means generates a comparison signal that maintains a predetermined one level when the level of the electric signal is less than the discrimination level and maintains a predetermined other level when the level of the electric signal is equal to or more than the discrimination level. From the change timing of the signal level of the first control signal,
Timer means for measuring a duration for which the comparison signal keeps one level or the other level; and a duration for which the duration measured by the timer means is maintained by the first control signal to keep the first switching means in a conductive state or a cutoff state. When it matches, it is determined that there is no failure,
2. The failure determination device for an electromagnet device according to claim 1, further comprising: determination means for determining that there is a failure when the duration does not match the holding time. 3. The method according to claim 1, wherein the determining unit determines that there is a failure in the path on the first coil side from the first connection point when the duration does not match the holding time and the duration is less than a predetermined time. 3. The electromagnet according to claim 2, wherein when the determination is not made and the duration is longer than a predetermined time, it is determined that there is a failure in the path on the side of the first switching means from the first connection point. 4. Device failure judgment device. 4. The failure determining means generates a comparison signal that maintains a predetermined one level when the level of the electric signal is lower than the discrimination level and maintains a predetermined other level when the level of the electric signal is higher than the discrimination level. A time point determined by a time corresponding to a duty ratio of the first control signal from a timing at which the first switching means switches from one of a conduction state and a cutoff state to any other state by the first control signal. Detecting means for detecting the presence / absence of a level change of the comparison signal within a predetermined determination period counted from, and responding to the output of the detecting means; determining that there is no failure when there is a level change; 2. The failure determination device for an electromagnet device according to claim 1, further comprising: a determination unit that determines that there is no failure. 5. The failure determining means generates a comparison signal that maintains a predetermined one level when the level of the electric signal is less than the discrimination level and maintains a predetermined other level when the level of the electric signal is equal to or higher than the discrimination level. Responding to an output of the detecting means, a forcing means for keeping the first switching means in a conductive state or a cut-off state during a predetermined inspection period, a detecting means for detecting the presence or absence of a change in the level of the comparison signal within the inspection period, 2. The failure determination device for an electromagnet device according to claim 1, further comprising: determination means for determining that there is no failure when there is no level change and determining that there is a failure when there is a level change. 6. The failure determination unit includes: a forcing unit that keeps the first switching unit in a conductive state or a cutoff state during a predetermined inspection period; and a signal level of the electric signal that is equal to or higher than the discrimination level during the inspection period. When it is determined that there is no failure in the path on the first switching means side from the first connection point, and when the signal level falls below the discrimination level during the inspection period, it is determined that there is a failure in the path on the first switching means side. 2. The failure determination device for an electromagnet device according to claim 1, further comprising a determination unit. 7. The failure judging means, when the level of the electric signal at the first connection point keeps less than another predetermined discrimination level that is equal to or less than the discrimination level during the inspection period,
It is determined that there is a failure in the path on the first coil side from the first connection point, and when the level becomes another discrimination level or more within the inspection period, there is no failure on the path on the first coil side from the first connection point. The failure determination device for an electromagnet device according to claim 5, further comprising a disconnection determination unit for determining. 8. A valve means having a valve element interposed in a fluid path through which a predetermined fluid passes, an opening degree determining means for outputting an instruction signal indicating a valve opening degree of the valve means, and a pair of magnetically coupled An electromagnet device, wherein the first coil displaces the valve in a direction in which the valve opening increases, and the second coil displaces the valve in a direction in which the valve opening decreases. A first switching means coupled in series with the coil, the first coil being excited when in a conductive state and the first coil being demagnetized in a disconnected state, and a second switching means being coupled in series with a second coil and in a conductive state, A second switching means which is energized and the second coil is demagnetized when in a shut-off state; and a first and a second means in response to an instruction signal from the opening degree determining means, wherein a duty ratio corresponding to the valve opening degree is determined mutually. A control signal, the first switch A first control signal for conducting / blocking the switching means and a second control signal for conducting / blocking the second switching means, wherein the first and second control signals are the second signals when the first switching means is in the conducting state. Signal generation for duty-controlling the first and second switching means so as to have a first period in which the switching means is in an off state and a second period in which the first switching means is in an off state and the second switching means is in a conduction state. Means, first comparing means for discriminating the signal level of the first electric signal at a first connection point between the first coil and the first switching means at a predetermined discriminating level, and responsive to an output from the first comparing means. Comparing the change pattern of the signal level of the first electric signal with the change pattern of the signal level of the first control signal, thereby obtaining the first coil and the first switch. Failure determination means for determining a failure in a first power supply path including a switching means; and a signal level of a second electric signal at a second connection point between the second coil and the second switching means at a predetermined discrimination level. A second comparing means for discriminating; and a signal level change pattern of the second control signal in response to an output from the second comparing means, the signal level change pattern of the second control signal being compared with the second control signal. And a second failure determining means for determining a failure in the second power supply path including the coil and the second switching means. 9. The fluid according to claim 1, wherein the fluid is intake air supplied to an internal combustion engine, and the fluid path is attached to a suction pipe for supplying air to the internal combustion engine. 9. The flow control device according to claim 8, wherein the flow control device is a bypass pipe that bypasses the position. 10. A display means for displaying that at least one of the first and second power supply paths has a failure, and when at least one of the first and second failure determination means determines that there is a failure, 10. An internal combustion engine control means for displaying the presence of a failure on the display means and further reducing the torque of the internal combustion engine when the failure is determined by the second failure determination means. A flow control device as described. 11. A fuel injection valve whose valve body is displaced to supply fuel to an internal combustion engine, a fuel injection amount determining means for deriving an instruction signal indicating a fuel flow rate from the fuel injection valve, and a pair of magnetically coupled fuel injection valves. An electromagnet device, wherein the first coil displaces the valve in a direction in which the valve opening increases, and the second coil displaces the valve in a direction in which the valve opening decreases. A first switching means which is serially coupled to one coil and which is energized when the conduction state is established and the first coil is demagnetized when the conduction state is established; a second switching means which is series coupled to the second coil and which is established when the conduction state is established Are excited and the second coil is demagnetized in the shut-off state. The second switching means and the duty ratio corresponding to the valve opening corresponding to the fuel flow rate in response to an instruction signal from the fuel injection amount determining means are mutually reciprocal. The first and the determined A second control signal, a first control signal to conduct / cut off the first switching means, and a second control signal for conducting / shutting off the second switching means occurs,
The first and second control signals include a first period in which the first switching unit is in a conducting state and a second switching unit in a blocking state, and a second period in which the first switching unit is in a blocking state and the second switching unit is in a conducting state. Signal generating means for duty-controlling the first and second switching means so as to have a period, and a signal level of the first electric signal at a first connection point between the first coil and the first switching means at a predetermined discrimination level. A first comparing means for performing level discrimination, and a signal level change pattern of the first control signal being compared with a signal level change pattern of the first control signal in response to an output from the first comparing means. First failure determination means for determining a failure in a first power supply path including one coil and first switching means, a second coil and a second switching means A second comparing means for discriminating the signal level of the second electric signal at the second connection point at a predetermined discrimination level, and a change timing of a signal level of the second electric signal in response to an output from the second comparing means. And a second failure judging means for judging a failure in the second power supply path including the second coil and the second switching means by comparing the change timing of the signal level of the second control signal with the second control signal. A fuel injection device for an internal combustion engine.