JP2012072870A - Solenoid valve driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solenoid valve driving device that prevents unnecessary power consumption.SOLUTION: Power-on time Ton is decided for supplying power to a coil for each cycle of a driving signal DR of a driving cycle time Tbase. In the power-on period from the start of one cycle of the driving signal till the lapse of the decided time Ton, the driving signal is maintained active-high until the lapse of the time Tp for supplying a peak current Ip to the coil. The driving signal is set to a pulse-train signal HD of a predetermined duty ratio till the end of the power-on time, and thereafter, the driving signal is set low till the end of one cycle. If the time Toff obtained by subtracting the decided power-on time from the driving cycle time is a predetermined value or less, the driving signal to be output is set to be a pulse-train signal from the lapse of the time Tp to the start of the next cycle, and mode of the driving signal from the start of the next cycle to the lapse of the time Tp is changed to a pulse-train signal. There is no need to supply peak current.

Description

  The present invention relates to a solenoid valve driving device that drives a solenoid valve (solenoid valve).

  The electromagnetic valve driving device drives the electromagnetic valve by turning on and off a switching element such as a MOSFET (field effect transistor) provided in series with an energization path for energizing the coil of the electromagnetic valve by a drive signal.

  Further, in this type of solenoid valve drive device, the drive signal is activated to turn on the switching element until a predetermined time elapses from the start of the energization period in the energization period of energizing the coil of the solenoid valve. By maintaining the level, a large peak current that can quickly move the valve body of the solenoid valve is caused to flow through the coil, and the remaining period from the end of the predetermined time until the end of the energization period is driven. By making the signal a pulse train signal that becomes an active level at a predetermined cycle and at a predetermined duty ratio, the energization current to the coil is limited to suppress power consumption (see, for example, Patent Document 1).

  By the way, when the solenoid valve to be driven is a linear solenoid valve in which the opening degree is adjusted, the technology for switching the drive signal form to the pulse train signal during the energization period as described above, and the energization period itself is PWM. It is conceivable to combine (pulse width modulation) control technology. Hereinafter, a specific example will be described.

  First, as shown in FIG. 9, the electromagnetic valve driving apparatus 100 of this example employs a high-side driving configuration in which a switching element (N-channel MOSFET in this example) Tr is disposed upstream of the coil L of the electromagnetic valve V. Yes. For this reason, one end of the coil L is connected to the ground line, and when the switching element Tr is turned on, the power supply voltage VB is applied to the other end of the coil L and a current flows through the coil L.

  And in the solenoid valve drive device 100, the drive signal DR which has periodicity as shown in FIG.9 (e) is produced | generated in the following procedure. In this example, the switching element Tr is turned on when the drive signal DR is high. That is, the active level of the drive signal DR is high.

  First, as shown in FIG. 9A, a one-shot pulse OS having the same period as the period Tbase of the drive signal DR and being high for a predetermined time Tp from the start of one period of the drive signal DR is generated. As shown in FIG. 9B, a pulse train signal HD (hereinafter referred to as a hold signal) HD whose cycle is shorter than the cycle Tbase and becomes high at a predetermined duty ratio is generated. Then, as shown in FIG. 9C, a base signal BA, which is a signal obtained by ORing the two signals OS and HD, is generated from the one-shot pulse OS and the hold signal HD.

  Furthermore, in the solenoid valve driving device 100, as shown in FIG. 9 (d), a driving duty signal that is a PWM signal that becomes high at the start of one cycle of the driving signal DR and the same cycle as the cycle Tbase of the driving signal DR. Create a DD. Among the high time and low time of the drive duty signal DD, the high time means the energization time Ton for energizing the coil L, and the low time means the non-energization time Toff for not energizing the coil L. A period in which the drive duty signal DD is high means an energization period in which the coil L is energized.

Then, in the solenoid valve drive device 100, as shown in FIG. 9 (e), a signal obtained by ANDing the drive duty signal DD and the base signal BA is generated as the drive signal DR.
For this reason, the drive signal DR is the predetermined time Tp from the start of one cycle in the energization period in which the drive duty signal DD is high (that is, the period from the start of one cycle until the energization time Ton elapses). Until the time elapses, and remains high until the end of the energization period. Further, the period from the end of the energization period to the end of one cycle of the drive signal DR (that is, the period of the non-energization time Toff in which the drive duty signal DD is low) remains low.

  Then, as shown in FIG. 10A, the switching element Tr is continuously turned on during the predetermined time Tp in which the drive signal DR remains high from the start of one cycle of the drive signal DR, and the coil A large peak current Ip that can move the valve body of the electromagnetic valve V from the initial position (fully closed position in this example) toward the operation completion position (fully opened position in this example) flows to L, and then the drive signal During the period in which the DR is in the form of the hold signal HD, the switching element Tr is turned on / off in response to the hold signal HD, so that the coil L has a valve body that is smaller than the peak current Ip but has moved from the initial position. A hold current Ih that can hold at least the position flows.

  When the drive signal DR remains low from the form of the hold signal HD, energization to the coil L is stopped. Then, the valve body of the electromagnetic valve V starts to return toward the initial position, and then the start timing of the drive signal DR of the next cycle comes before the valve body returns to the initial position, and the drive signal DR becomes high. If it becomes, the solenoid valve V will move to the operation completion position of the valve body without returning to the fully closed state (completely closed state). In FIG. 10, “current value” means a current flowing through the coil of the solenoid valve. In FIG. 10, “closed” and “open” in the “valve” stage do not mean fully closed and fully open, but the rise from “closed” to “open” The timing when the movement starts in the direction of the operation completion position is shown, and the fall from “open” to “closed” indicates “the timing when the valve body starts returning in the direction of the initial position”. These also apply to other figures described later.

  Therefore, the ratio (= Ton / Tbase) of the energization time Ton when the drive signal DR becomes high or the hold signal HD to the cycle Tbase is the duty ratio of the drive signal DR. In order to distinguish the ratio from the duty ratio of a general pulse train signal (that is, the duty ratio of a pulse train signal in which the sum of a set of consecutive high time and low time is one cycle) To tell. In the present specification, a percentage (%) is used as a unit of the duty ratio (including the drive duty ratio) unless otherwise specified.

JP 05-272391 A

  By the way, in the above-described conventional solenoid valve driving apparatus 100, as shown in FIG. 10 (B), even when the driving duty ratio is less than 100%, when the driving duty ratio becomes a predetermined value or more, it extends over a plurality of cycles of the driving signal DR. Thus, the valve body of the electromagnetic valve V moves toward the operation completion position without returning to the direction of the initial position.

  That is, if the delay time from when the form of the drive signal DR changes from the hold signal HD remains low until the valve body starts to return to the initial position direction is “Tcs” (see FIG. 10A), the drive duty If the ratio increases and the non-energization time Toff (= Tbase-Ton) becomes shorter than Tcs, the drive signal DR remains low before the valve body begins to return to the initial position direction. Since the drive signal DR becomes high again at the start of the next cycle, the valve body continues to move toward the operation completion position without returning to the direction of the initial position.

  Here, when the valve body of the solenoid valve V is moved to the operation completion position, generally, the drive duty ratio is gradually increased. Therefore, when the drive duty ratio is set to be equal to or greater than the predetermined value. The solenoid valve V is in a fully open state or almost fully open state. In such a situation, even if the peak current Ip is not supplied to the coil L, the valve body does not return toward the initial position. It is thought that the open state of the solenoid valve V can be maintained.

  However, in the conventional solenoid valve driving apparatus 100, even in such a situation, the peak current Ip is allowed to flow through the coil L while the drive signal DR remains high for a predetermined time Tp from the start of each cycle of the drive signal DR. For this reason, power corresponding to the peak current Ip is wasted.

  This invention pays attention to such a point, and it aims at provision of the solenoid valve drive device which can prevent useless power consumption.

  According to another aspect of the present invention, there is provided an electromagnetic valve driving device that turns on and off a switching element provided in series with an energization path for energizing a coil of an electromagnetic valve by a drive signal having a predetermined drive cycle time Tbase as a cycle. In addition to the determination means and the drive signal output means for outputting the drive signal to the switching element, a determination means and a signal form change means are further provided.

  In this electromagnetic valve drive device, the determining means determines the energization time Ton for energizing the coil in one cycle of the current drive signal for each cycle of the drive signal. The ratio of the energization time Ton to the drive cycle time Tbase is the aforementioned drive duty ratio.

  The drive signal output means includes a solenoid valve from the start of the one cycle in the energization period that is a period from the start of one cycle of the drive signal to the lapse of the energization time Ton determined by the determination means. Until the peak current supply time Tp for passing a peak current that can be moved from the initial position toward the operation completion position through the coil has passed, the drive signal is the active level that turns on the switching element. Until the end of the energization period, the drive signal is a pulse train signal having an active level with a cycle shorter than the drive cycle time Tbase and a predetermined duty ratio, which is smaller than the peak current. Hold current pulse train signal for flowing a hold current that can hold at least the position of the valve element moved from the initial position to the coil The drive signal is set to an inactive level (that is, a level for turning off the switching element) from the end of the energization period to the end of one cycle of the drive signal. .

  Further, in this solenoid valve drive device, the determination means operates every time the determination means determines the energization time Ton, and the determination means is the remaining time obtained by subtracting the determined energization time Ton from the drive cycle time Tbase. It is determined whether or not the non-energization time Toff (= Tbase-Ton) is equal to or less than a predetermined lower limit value Toffmin. The lower limit value Toffmin is longer than the delay time Tcs from when the form of the drive signal to the switching element changes from the hold current pulse train signal to the inactive level until the valve body of the solenoid valve starts to return to the initial position. It is set to a small value.

If the non-energization time Toff is determined by the determination means to be less than or equal to the lower limit value Toffmin (positive determination), the signal form changing means performs the following operation.
In other words, the signal form changing means changes the determined energization time Ton to the drive cycle time Tbase, and the drive signal output this time by the drive signal output means is changed to the next 1 after the elapse of the peak current supply time Tp. The pulse signal for the hold current is made until the start of the cycle, and the drive signal output means outputs from the start of one cycle of the next drive signal until the peak current supply time Tp elapses. The configuration is changed to a current suppression pulse train signal that becomes an active level at a predetermined duty ratio equal to or higher than the duty ratio of the hold current pulse train signal in a cycle shorter than the drive cycle time Tbase.

  In such a solenoid valve drive device, when the energization time Ton determined by the determining unit is a value that does not satisfy “Toff ≦ Toffmin” and is less than “Tbase−Toffmin”, the determination unit determines negative. (In other words, it is determined that “Toff ≦ Toffmin” is not satisfied), and the signal form changing means does not function.

  Therefore, in that case, the drive signal output by the drive signal output means is the peak current from the start of one cycle in the energization period from the start of one cycle until the energization time Ton determined by the determination means elapses. The period until the supply time Tp elapses (hereinafter referred to as the peak current supply period) remains at the active level, and thereafter becomes the hold current pulse train signal until the energization period ends, and the energization period ends. Until the end of one cycle of the drive signal, the inactive level remains.

  The valve body of the solenoid valve moves in the direction of the operation completion position in the peak current supply period in which the drive signal remains at the active level, and at least the position is maintained in the period in which the drive signal becomes the hold current pulse train signal. When the energization period in one cycle ends and the drive signal becomes an inactive level, it starts to return to the initial position.

  On the other hand, when the energization time Ton determined by the determination unit is a value that satisfies “Toff ≦ Toffmin” and is equal to or greater than “Tbase−Toffmin”, the determination unit determines that the determination is positive (that is, “Toff ≦ Toffmin”). The signal form changing means functions.

  Then, the drive signal of the current cycle output by the drive signal output means is a hold current pulse train signal from when the peak current supply time Tp has elapsed (at the end of the peak current supply period) to the start of the drive signal of the next cycle. Further, the signal form in the peak current supply period of the drive signal of the next cycle is not the active level but a current suppressing pulse train signal. Therefore, the drive signal is a pulse train signal (hold current pulse train signal or current suppression) that can hold at least the valve body position of the solenoid valve from the end of the peak current supply period in the current cycle to the end of the energization period in the next cycle. Pulse train signal).

For this reason, even if the drive signal of the next cycle does not remain at the active level during the peak current supply period, at least the valve body position of the electromagnetic valve is maintained.
That is, if the energization time Ton determined by the determining means is equal to or longer than “Tbase-Toffmin” and the determining means makes an affirmative determination, the signal form changing means does not function and the drive signal of the current cycle is Even if the inactive level remains from the hold current pulse train signal, the time for the inactive level (non-energization time Toff) is shorter than the delay time Tcs until the valve body starts to return to the initial position. The valve body does not return to the initial position until at least the energization period with the drive signal of the next cycle ends.

  By paying attention to this point, in the solenoid valve drive device of the present invention, even if the drive signal of the next cycle does not remain at the active level during the peak current supply period, the signal form changing means functions. At least the valve element position is maintained.

  The drive signal does not have to remain at the active level during the peak current supply period. This means that the switching element does not remain on during the peak current supply period, and less current flows through the coil. This means that unnecessary power consumption can be prevented.

  In addition, when the determination unit continuously makes an affirmative determination (in other words, when the energization time Ton determined by the determination unit is continuously equal to or longer than “Tbase-Toffmin”), the drive signal has a plurality of cycles. The pulse train signal (hold current pulse train signal or current suppression pulse train signal) remains unchanged.

  On the other hand, the determining means may determine the value of the drive duty ratio (Ton / Tbase) or the non-energizing time Toff as the energizing time Ton without directly determining the value of the energizing time Ton. This is because the energization time Ton is determined if either the drive duty ratio or the non-energization time Toff is determined.

  Further, the determination means determines whether or not the drive duty ratio or energization time Ton is equal to or greater than a predetermined value satisfying “Toff ≦ Toffmin” as a determination of whether or not “Toff ≦ Toffmin”. But it ’s okay.

  By the way, as described in claim 2, the hold current pulse train signal has a current that is smaller than the peak current but that can move the valve body of the solenoid valve toward the operation completion position as the hold current. Preferably, the pulse train signal is passed through the coil.

  In this way, the energization time Ton is changed from, for example, 0 or a value close to 0 to a value that is affirmatively determined by the determination means (a value equal to or greater than “Tbase-Toffmin”), and the setting state is changed. This is because even if the operation is continued, the valve body of the electromagnetic valve can be reliably moved to the operation completion position.

  Next, in the electromagnetic valve driving device according to claim 3, in the electromagnetic valve driving device according to claims 1 and 2, the current suppressing pulse train signal is a pulse train signal having the same cycle and duty ratio as the hold current pulse train signal.

  According to this configuration, when the determination unit makes an affirmative determination (when the signal form changing unit functions), the drive signal output unit outputs the same pulse train signal as the hold current pulse train signal as the current suppression pulse train signal. Therefore, there is an advantage that the process for outputting the drive signal can be simplified.

  On the other hand, in the electromagnetic valve driving device according to claim 4, in the electromagnetic valve driving device according to claims 1 and 2, the signal form changing means is such that the determination result of the determining means is a negative determination result (the non-energization time Toff is less than or equal to the lower limit value Toffmin. The determination result) is changed to an affirmative determination result (determination result that the non-energization time Toff is equal to or lower than the lower limit value Toffmin), the duty ratio of the current suppression pulse train signal is changed to the duty ratio of the hold current pulse train signal. When an initial value larger than the ratio is set and the determination result of the determination means is continuously affirmative determination result (that is, when the determination result is affirmative both in the previous time and this time), the current suppression pulse train signal The duty ratio is equal to or higher than the duty ratio of the hold current pulse train signal, and the duty cycle of the current suppression pulse train signal in the drive signal of the previous cycle is set. Set to a value smaller than the duty ratio.

  Therefore, when the determination means continuously makes an affirmative determination, the duty ratio of the current suppressing pulse train signal during the peak current supply period of the drive signal gradually decreases from the initial value for each cycle of the drive signal, The duty ratio of the hold current pulse train signal is approached.

  According to the electromagnetic valve driving apparatus of claim 4, the valve body of the electromagnetic valve is moved from the initial position to the operation completion position by gradually approaching the drive duty ratio (Ton / Tbase) to 100%. When performing the control, the valve body can be moved to the operation completion position quickly as compared with the electromagnetic valve driving device of claim 3. This is because the duty ratio of the current suppression pulse train signal during the peak current supply period of each drive signal after the judgment means has continuously made a positive judgment becomes larger than the duty ratio of the hold current pulse train signal. It is. For this reason, the operation responsiveness and power saving performance of the valve body can be achieved in a well-balanced manner.

  Next, in the electromagnetic valve driving device according to claim 5, in the electromagnetic valve driving device according to claims 1 to 4, the electromagnetic valve driving device drives a plurality of electromagnetic valves, and each of the electromagnetic valves is operated. , The switching element, the determination means, the drive signal output means, the determination means, and the signal form change means. The start timing of one cycle of each drive signal corresponding to each of the solenoid valves is equal to or longer than the peak current supply time Tp so that periods (peak current supply periods) in which the drive signals remain at the active level do not overlap each other. Is shifted by a predetermined time.

  And according to such a solenoid valve drive device, it is avoided that a big peak current flows through the coils of a plurality of solenoid valves at the same time. As a result, the voltage of the power source for passing a current through each coil is instantaneous. It can prevent that it falls.

  Next, in the electromagnetic valve driving device according to a sixth aspect, in the electromagnetic valve driving device according to the fifth aspect, the non-energization time Toff is set to a lower limit value by the determining means for the specific drive signal that is one of the drive signals. In a situation where the determination means has determined the energization time Ton to be 0 for a drive signal different from the specific drive signal that has been continuously determined (affirmative determination) to be Toffmin or less. When a request to start driving of the solenoid valve corresponding to the drive signal occurs, the start timing of one cycle of the specific drive signal arrives earlier than the start timing of one cycle of the other drive signal. Then, the start timing of one cycle of the other drive signal is advanced to the start timing of one cycle of the specific drive signal, and the start timing of the other drive signal is activated at the earlier start timing of one cycle. To start output in Ibureberu.

  That is, in this case, since the specific drive signal remains a pulse train signal, driving of the solenoid valve corresponding to another drive signal is started at the original one cycle start timing of the specific drive signal (ie, another Even when the output of the drive signal at the active level is started), the peak current does not simultaneously flow through the coils of the plurality of solenoid valves, and the power supply voltage does not decrease. Therefore, according to such a solenoid valve drive device, it is possible to prevent a momentary drop in the power supply voltage and improve the drive start response of the solenoid valve corresponding to the other drive signal.

  Even if the current suppression pulse train signal is not a pulse train signal having the same period and duty ratio as that of the hold current pulse train signal, the current suppression pulse train signal is used from the viewpoint of simplifying the process for outputting the drive signal. The period of the pulse train signal is preferably set to the same value as the period of the hold current pulse train signal. However, it is of course possible to make the periods different between the current suppressing pulse train signal and the hold current pulse train signal.

It is explanatory drawing explaining the structure and basic operation | movement of the solenoid valve drive device of embodiment. It is a flowchart showing the process which a microcomputer performs. It is a 1st explanatory view explaining an operation of an embodiment. It is the 2nd explanatory view explaining an operation of an embodiment. It is the 1st explanatory view for explaining the 1st modification. It is the 2nd explanatory view for explaining the 1st modification. It is the 1st explanatory view for explaining the 2nd modification. It is the 2nd explanatory view for explaining the 2nd modification. It is explanatory drawing explaining the structure and operation | movement of the conventional solenoid valve drive device. It is explanatory drawing explaining a subject.

  Hereinafter, an electromagnetic valve driving apparatus according to an embodiment to which the present invention is applied will be described. Note that the electromagnetic valve driving device of the present embodiment drives, for example, a plurality (three in the present embodiment) of linear solenoid valves provided in a hydraulic path for shifting the automatic transmission of an automobile.

  As shown in FIG. 1A, one ends of coils L1 to L3 of three linear solenoid valves (hereinafter simply referred to as solenoid valves) V1 to V3 are connected to a ground line, and each of the coils L1 to L3 is The other ends are connected to terminals J1 to J3 of the electromagnetic valve driving device 1, respectively.

  The electromagnetic valve drive device 1 includes switching elements (N-channel MOSFETs in this embodiment) Tr1 to Tr3 for causing current to flow through the coils L1 to L3 for each of the electromagnetic valves V1 to V3.

  Of the two output terminals of each switching element Trx (x is any one of 1 to 3 and the same applies hereinafter), one (the drain in this embodiment) is connected to the battery voltage VB as the power supply voltage. The other (the source in the present embodiment) is connected to the side opposite to the ground line side of the coil Lx via the terminal Jx of the electromagnetic valve driving device 1. When the switching element Trx is turned on, the battery voltage VB is applied to the side of the coil Lx opposite to the ground line side, a current flows through the coil Lx, and the electromagnetic valve Vx is driven to the open side.

  The switching elements Tr <b> 1 to Tr <b> 3 are built in the output driver 2 provided in the electromagnetic valve driving device 1. The output driver 2 is an IC in which a plurality of elements such as switching elements Tr1 to Tr3 and a logic circuit are contained in one package.

  Further, the electromagnetic valve driving device 1 includes a microcomputer 3 that performs processing for controlling the electromagnetic valves V1 to V3, and the output driver 2 is based on a signal to be described later output from the microcomputer 3, and the switching element Tr1. Drive signals DR1 to DR3 for .about.Tr3 are generated. The output driver 2 outputs the generated drive signals DR1 to DR3 to the control terminals (gates in the present embodiment) of the switching elements Tr1 to Tr3, thereby turning on and off the switching elements Tr1 to Tr3. V1 to V3 are driven.

Here, the drive signals DR1 to DR3 are signals having the same form as the drive signal DR in the electromagnetic valve drive device 100 shown in FIG.
That is, as shown in FIG. 1B, each drive signal DRx (DR1 to DR3) has the same constant period Tbase, and has a signal form that means the energization period to the coil Lx in the one period. This is a signal for changing the duration (that is, the energization time Ton). Each drive signal DRx remains high until the predetermined time Tp elapses from the start of one cycle in the energization period from the start of one cycle until the energization time Ton elapses. Until the energization period ends, the hold signal HD, which is a pulse train signal having a cycle shorter than the cycle Tbase of the drive signal and becomes high at a predetermined duty ratio, and one cycle of the drive signal after the energization period ends. The period until the end of is kept low (see the “DR1” and “DR2” stages in FIG. 1B). However, if the energization time Ton is shorter than the predetermined time Tp, it remains high for the energization time Ton (<Tp) from the start of one cycle, and then low until the end of one cycle of the drive signal. (Refer to the stage of “DR3” in FIG. 1B).

  In the present embodiment, for example, the cycle Tbase of the drive signal DRx is 20 ms, the predetermined time Tp is 5 ms, the cycle of the hold signal HD is 250 μs, and the duty ratio of the hold signal HD is 50%. .

  Further, as shown in FIG. 1B, the start timing of one cycle of each of the drive signals DR1 to DR3 is such that the period of the predetermined time Tp during which the drive signals DR1 to DR3 remain high does not overlap each other. Are sequentially shifted by at least the predetermined time Tp. In the present embodiment, the time is shifted by a predetermined time Tp.

  This is because the period from the start of one cycle of the drive signal DRx to the elapse of the predetermined time Tp and the period of the predetermined time Tp in which the drive signal DRx remains high is the initial position of the valve body of the electromagnetic valve Vx. Since this is a peak current supply period for flowing a large peak current Ip that can be quickly moved from the (completely closed position in this embodiment) to the operation completion position (fully open position in this embodiment), the coil Lx. If the period overlaps with a plurality of drive signals, the peak current Ip flows through a plurality of coils at the same time, and the battery voltage VB as the power supply voltage is instantaneously reduced. Therefore, the start timing of one cycle of each of the drive signals DR1 to DR3 is shifted by a predetermined time Tp.

  In FIG. 1B, Tonx (Ton1 to Ton3) indicates the energization time for energizing the coil Lx in one cycle of the drive signal DRx, and Toffx (Toff1 to Toff3) is 1 of the drive signal DRx. In the period, a non-energization time (= Tbase-Tonx) in which the coil Lx is not energized is shown. On the other hand, in this embodiment, an N-channel MOSFET is used as the switching element Trx, and the coil Lx is energized in the high-side drive mode. Therefore, the high level of the drive signal DRx to the switching element Trx is set to the battery voltage VB (for example, typically 10 -14V), which is, for example, 20V, and the low level of the drive signal DRx is, for example, 0V.

  Next, signals output from the microcomputer 3 to the output driver 2 in order to generate the drive signals DR1 to DR3 will be described. Here, the signal for generating the drive signal DR1 will be described in detail, but the same applies to the signals for generating the other drive signals DR2 and DR3.

  As shown in the first stage in FIG. 1B, the microcomputer 3 is a signal having the same cycle as the cycle Tbase of the drive signal DR1, and is high for a predetermined time Tp from the start of one cycle of the drive signal DR1. After that, during the period until one cycle of the drive signal DR1 ends, the base signal BA1 in the form of the hold signal HD described above is generated and output.

  Further, as shown in the fourth stage in FIG. 1B, the microcomputer 3 has a drive duty which is a PWM signal that is high at the same period as the period Tbase of the drive signal DR1 and at the start of one period of the drive signal DR1. A signal DD1 is generated and output.

  In the output driver 2, the signal generation circuit 11 provided corresponding to the switching element Tr1 takes the logical product of the base signal BA1 from the microcomputer 3 and the drive duty signal DD1, and the logic of both the signals BA1 and DD1. A signal obtained by converting the high level of the product signal to the above-described 20 V (that is, a voltage that can sufficiently turn on the switching element Tr1) is output as a drive signal DR1 to the gate of the switching element Tr1. Therefore, the drive signal DR1 is a signal as shown in the seventh row in FIG.

  Further, as shown in the second stage in FIG. 1B, the microcomputer 3 generates a signal having the same signal form as the base signal BA1 and having a phase delayed by a predetermined time Tp with respect to the base signal BA1. Output as BA2, and as shown in the third stage in FIG. 1B, the phase is the same as the base signal BA1 and the phase is delayed by a time of “predetermined time Tp × 2” with respect to the base signal BA1. The signal is output as the base signal BA3.

  Further, as shown in the fifth stage in FIG. 1B, the microcomputer 3 is a drive that is a PWM signal having the same period as the drive duty signal DD1 and a phase delayed from the drive duty signal DD1 by a predetermined time Tp. A duty signal DD2 is generated and output. As shown in the sixth stage in FIG. 1B, the cycle is the same as that of the drive duty signal DD1 and the phase is “predetermined time Tp × 2” with respect to the drive duty signal DD1. The drive duty signal DD3, which is a PWM signal delayed by the time, is generated and output.

  The output driver 2 also includes signal generation circuits 12 and 13 similar to the signal generation circuit 11 for the switching elements Tr2 and Tr3. The signal generation circuit 12 drives the base signal BA2 from the microcomputer 3 and drives it. The drive signal DR2 is generated from the duty signal DD2 and output to the gate of the switching element Tr2. Similarly, the signal generation circuit 13 generates the drive signal DR3 from the base signal BA3 from the microcomputer 3 and the drive duty signal DD3. Generated and output to the gate of the switching element Tr3.

  As described above, among the high time and low time of the drive duty signal DDx, the high time means the energization time Ton (Tonx) in which the coil Lx is energized, and the low time does not energize the coil Lx. It means a non-energization time Toff (Toffx), and a period in which the drive duty signal DDx is high means an energization period in which the coil Lx is energized. In the example of FIG. 1B, the energization time Ton3, which is the high time of the drive duty signal DD3, is shorter than the predetermined time Tp, so the drive signal DR3 remains high for the energization time Ton3 from the start of one cycle. After that, it remains low until one cycle of the drive signal DR3 ends.

Then, when the drive signal DRx generated as described above is supplied to the gate of the switching element Trx, a current flows through the coil Lx of the electromagnetic valve Vx to drive the electromagnetic valve Vx.
That is, as shown in FIG. 3A, the switching element Trx continues to be on for a predetermined time Tp from the start of one cycle of the drive signal DRx, and the peak current Ip flows through the coil Lx. During the period in which the drive signal DRx is in the form of the hold signal HD, the switching element Trx is turned on / off in accordance with the hold signal HD, so that the coil Lx has a valve element that has moved from the initial position although it is smaller than the peak current Ip. A hold current Ih that can hold at least the position of the current flows. In the present embodiment, the hold current Ih is actually set to a value that allows the valve body of the solenoid valve to move toward the operation completion position although it is smaller than the peak current Ip. In other words, the hold signal HD has a cycle and a duty ratio that are smaller than the peak current Ip as the hold current Ih, but a current that can move the valve body of the solenoid valve toward the operation completion position is passed through the coil. It is set to a possible value.

  When the drive signal DRx remains low from the form of the hold signal HD, the energization to the coil Lx is stopped, and when a predetermined delay time Tcs has elapsed from that point, the valve body of the electromagnetic valve Vx is in the direction of the initial position. Will begin to return. Therefore, before the valve body starts to return to the initial position, or at least before the valve body returns to the initial position, the start timing of the drive signal DRx in the next cycle arrives and the drive signal DRx becomes high. In this case, the solenoid valve Vx is moved to the operation completion position without returning to the fully closed state.

  Therefore, the opening degree of the solenoid valve Vx can be adjusted by controlling the drive duty ratio, which is the ratio (= Ton / Tbase) of the energization time Ton when the drive signal DRx is high or the hold signal HD to the period Tbase. . In the present embodiment, the duty ratio of the drive duty signal DDx is the drive duty ratio.

Next, each process performed for the microcomputer 3 to output the drive duty signals DD1 to DD3 and the base signals BA1 to BA3 will be described with reference to FIG.
First, FIG. 2A is a flowchart showing processing performed by the microcomputer 3 to output the drive duty signals DD1 to DD3.

  The process of FIG. 2A is performed for each of the drive duty signals DD1 to DD3. Here, the process is described as a process for outputting DDx which is one of the drive duty signals DD1 to DD3. . 2A is executed every cycle of the drive signal DRx generated based on the drive duty signal DDx, for example, immediately before the start timing of the cycle.

  When the microcomputer 3 starts the process of FIG. 2A, first, in S110, the microcomputer 3 determines the drive duty ratio (= Ton / Tbase) of the drive signal DRx output this time. For example, the speed of the automatic transmission and the necessity for shifting are determined from the traveling speed (vehicle speed) of the automobile, the driver's accelerator operation amount, and the like, and the target of the electromagnetic valve Vx corresponding to the drive signal DRx is determined from the determination result. The opening degree is determined, and the drive duty ratio necessary for realizing the target opening degree is determined. Since the period Tbase is known, determining the drive duty ratio is the same as determining the energization time Ton or the non-energization time Toff.

  Then, in the next S120, it is determined whether or not the drive duty ratio determined in S110 is equal to or greater than a predetermined value Dth. The predetermined value Dth is a value at which the non-energization time Toff (= Tbase-Ton) determined by the determined drive duty ratio is equal to or less than a predetermined lower limit value Toffmin, and the lower limit value Toffmin is the delay time Tcs described above. Is a smaller value. For this reason, in S120, it can be said that it is determined whether or not the non-energization time Toff determined by the drive duty ratio determined in S110 is equal to or less than the lower limit value Toffmin. In the present embodiment, the predetermined value Dth is set to 95%, for example. In this case, since “Tbase = 20 ms”, the lower limit value Toffmin is set to 1 ms. .

If it is determined in S120 that the drive duty ratio is not equal to or greater than the predetermined value Dth (negative determination), the process directly proceeds to S140.
If it is determined in S120 that the drive duty ratio is equal to or greater than the predetermined value Dth (affirmative determination), the process proceeds to S130, and the determined drive duty ratio is changed to 100%. This means that the energization time Ton when the drive signal DRx is high or the hold signal HD is reset to the same value as the period Tbase (in other words, the non-energization time Toff is set to 0). Then, the process proceeds to S140.

  In S140, the PWM in the microcomputer 3 for outputting the drive duty signal DDx based on the drive duty ratio determined at that time (that is, the value determined in S110 or 100% changed in S130). Set to the circuit as the duty ratio of the PWM signal. Then, the PWM circuit outputs the PWM signal having the cycle of “Tbase” and the duty ratio set in S140 as the drive duty signal DDx, but the output start timing at the new duty ratio is coming from now on. This is the start timing of one cycle of the drive signal DRx.

  2B is performed for each cycle of the drive signal DRx, the drive duty signal DDx, which is a PWM signal having the same duty ratio as the drive duty ratio, is output from the microcomputer 3. However, if an affirmative determination is made in S120, the drive duty ratio is changed to 100% in S130, so that the drive duty signal DDx is present over the current one cycle Tbase as shown in FIG. 4B. Stay high.

  The PWM circuit is provided for each of the drive duty signals DD1 to DD3, and the timing at which each PWM circuit starts outputting the drive duty signals DD1 to DD3 is a predetermined time as shown in FIG. It is shifted by Tp.

Next, FIG. 2B is a flowchart showing a process performed by the microcomputer 3 to output the base signals BA1 to BA3.
The process of FIG. 2B is performed for each of the base signals BA1 to BA3. Here, the process is described as a process for outputting BAx that is one of the base signals BA1 to BA3. 2B is started at every start timing of one cycle of the drive signal DRx generated based on the base signal BAx. Therefore, the processing of FIG. 2B for each of the base signals BA1 to BA3 is started with a shift by the predetermined time Tp described above.

  When the microcomputer 3 starts the process shown in FIG. 2B, first, in S210, the microcomputer 3 determines whether or not an affirmative determination is made in S120 regarding the drive signal DRx in the previous cycle. If the affirmative determination is not made in S120 for the drive signal DRx in the previous cycle (if a negative determination is made), the process proceeds to S220.

  In S220, the base signal BAx is kept high for the predetermined time Tp described above (that is, during the predetermined time Tp from the start of one cycle of the drive signal DRx), and when the predetermined time Tp has elapsed, S240 The base signal BAx is output in the form of the hold signal HD until one cycle of the drive signal DRx ends.

Therefore, if the negative determination is made in S120 with respect to the drive signal DRx in the previous cycle, the base signal BAx has the form as shown in FIG.
On the other hand, in S210, when it is determined that the drive signal DRx of the previous cycle has been affirmed in S120, the process proceeds to S230, and during a predetermined time Tp (that is, from the start of one cycle of the drive signal DRx). During a predetermined time Tp), the base signal BAx is output in the form of the hold signal HD without being kept high. When the predetermined time Tp elapses, the process proceeds to S240, and the base signal BAx is continuously output in the form of the hold signal HD until one cycle of the drive signal DRx is completed.

  Therefore, if the affirmative determination is made in S120 with respect to the drive signal DRx in the previous cycle, the base signal BAx is also during the predetermined time Tp from the start timing of one cycle of the drive signal DRx, as shown in FIG. The hold signal HD is formed, and eventually the hold signal HD is formed for one period of the drive signal DRx.

Next, the operation of the electromagnetic valve driving device 1 as described above will be described.
First, when a negative determination is made in S120 of FIG. 2A, the process of S130 (that is, the duty of the drive duty signal DDx) is performed on the drive duty signal DDx that is the source of the drive signal DRx in the current cycle. For the base signal BAx that is the source of the drive signal DRx in the next cycle, the processing in S230 (that is, the base signal BAx is changed from the start of the cycle to the hold signal HD) is not performed. The process to change is not performed.

  Therefore, in this case, the drive duty signal DDx output from the microcomputer 3 is a PWM signal having the same duty ratio as the drive duty ratio as shown in FIG. 1B, and the base signal BAx output from the microcomputer 3 is also The basic signal form shown in FIG. For this reason, the drive signal DRx to the switching element Trx has the normal signal form shown in FIG. 1B or 3A.

  Then, the valve body of the electromagnetic valve Vx moves quickly in the direction of the operation completion position during the predetermined time Tp during which the drive signal DRx remains high, and during the period in which the drive signal DRx takes the form of the hold signal HD. However, if the drive signal DRx remains low from the form of the hold signal HD, it starts to return to the initial position when it moves in the direction of the operation completion position although it is slow.

  On the other hand, if “YES” is determined in S120 in FIG. 2A, the process of S130 is performed for the drive duty signal DDx that is the source of the drive signal DRx in the current cycle, and further, in the next cycle. The process of S230 is also performed for the base signal BAx that is the source of the drive signal DRx.

  Therefore, in this case, since the drive duty signal DDx of the current cycle from the microcomputer 3 remains high for one cycle as shown in FIG. 4B, the drive signal of the current cycle to the switching element Trx. DRx remains the hold signal HD from the end of the peak current supply period of the predetermined time Tp to the start of the next cycle, as shown in the dashed-dotted ellipse in FIG. Further, as shown in FIG. 4B, the base signal BAx of the next period from the microcomputer 3 is in the form of the hold signal HD from the start timing of the period to the predetermined time Tp, and therefore in FIG. As shown in the ellipse of the two-dot chain line, the drive signal DRx of the next cycle has a signal form in the peak current supply period that is not high but a hold signal HD.

Therefore, the drive signal DRx takes the form of the hold signal HD from the end of the peak current supply period in the current cycle to the elapse of the energization time Ton in the next cycle.
For this reason, even if the drive signal DRx of the next cycle does not remain high during the peak current supply period, at least the valve body position of the electromagnetic valve Vx is maintained.

  That is, when the drive duty ratio determined in S110 is equal to or greater than the predetermined value Dth, if the processes in S130 and S230 are not performed, the drive signal DRx and the current in the coil Lx are as shown in FIG. 4A, which is similar to FIG. 4A, and the time during which the drive signal DRx in this period remains low (the non-energization time Toff) is shorter than the delay time Tcs described above. Does not return to the direction of the initial position at least until the energization period with the drive signal DRx in the next cycle ends.

  Therefore, in the solenoid valve drive device 1 of the present embodiment, when the drive duty ratio determined in S110 is equal to or greater than the predetermined value Dth, the processes of S130 and S230 are performed, and the drive signal DRx in the next cycle is performed. Is not required to remain high during the peak current supply period. The drive signal DRx does not have to remain high during the peak current supply period. This means that the switching element Trx does not remain on during the peak current supply period, and the current flowing through the coil Lx is small. Therefore, according to the electromagnetic valve driving device 1 of this embodiment, wasteful power consumption can be prevented.

  In the case where an affirmative determination is made continuously in S120 of FIG. 2A (that is, when the drive duty ratio determined in S110 is continuously greater than or equal to the predetermined value Dth), the result is shown in FIG. 4B. Thus, the drive signal DRx remains the hold signal HD over a plurality of periods.

  In S120, for example, it may be determined whether the energization time Ton determined by the drive duty ratio is equal to or greater than a predetermined value satisfying “Toff ≦ Toffmin”, or the non-energization time Toff determined by the drive duty ratio. It may be directly determined whether or not is less than or equal to the lower limit value Toffmin.

  On the other hand, in the present embodiment, the hold current Ih that is passed through the coil Lx by the hold signal HD is set to a value that can move the valve body of the solenoid valve Vx toward the operation completion position. Alternatively, even if it is changed from a value close to 0 to a value equal to or greater than the predetermined value Dth at once and the setting state is continued, it takes a while, but the valve body of the electromagnetic valve Vx can be reliably moved to the operation completion position. it can.

  However, the hold current Ih may be a minimum current that can hold the valve element position of the electromagnetic valve Vx. In this case, when fully opening the solenoid valve Vx, for example, the solenoid valve Vx is fully opened by gradually increasing the drive duty ratio in a range less than the predetermined value Dth, and then the drive duty ratio is set to the predetermined value Dth or more. If set to, the solenoid valve Vx can be maintained in a fully open state.

  In the present embodiment, in S230 of FIG. 2B, the form from the start of one cycle of the base signal BAx (and the form from the start of one cycle of the drive signal DRx) is changed to the hold signal HD. Therefore, the process for outputting the drive signal DRx can be simplified as compared with the case of changing to a pulse train signal having a different cycle and duty ratio from the hold signal HD.

  On the other hand, in the present embodiment, the process of S110 in FIG. 2A by the microcomputer 3 corresponds to the determining means, the process of S140 in FIG. 2A by the microcomputer 3, the PWM circuit in the microcomputer 3, and the microcomputer 3 The processes of S220 and S240 in FIG. 2B and the signal generation circuits 11 to 13 in the output driver 2 correspond to drive signal output means. The processing of S120 in FIG. 2A by the microcomputer 3 corresponds to a determination unit, and the processing of S130 in FIG. 2A by the microcomputer 3 and the processing of S210 and S230 in FIG. This corresponds to signal form changing means. In the present embodiment, the hold signal HD corresponds to a hold current pulse train signal, and also corresponds to a current suppression pulse train signal. Further, the predetermined time Tp corresponds to the peak current supply time.

Next, some modifications will be described.
[First Modification]
By gradually increasing the drive duty ratio, the control for switching the solenoid valve Vx from the fully closed state to the fully open state is performed by rebounding the valve body (that is, the valve body violently hits the operation completion position and returns). It is effective in preventing.

  Here, in the solenoid valve drive device 1 of the above-described embodiment, as shown in the upper part of FIG. 5, the actual drive duty ratio is 100% in the control region where the determined drive duty ratio is equal to or greater than the predetermined value Dth. At the same time, in the control region, the form of the drive signal DRx does not remain high, but only the hold signal HD (see FIG. 4B), so that the electromagnetic signal is shown as the solid line waveform in the lower part of FIG. The increasing speed of the valve opening (the moving speed of the valve body), which is the opening of the valve Vx, decreases.

  That is, in the lower part of FIG. 5, the waveform indicated by the dotted line reflects the determined drive duty ratio in the drive signal DRx and the drive signal DRx even if the determined drive duty ratio is equal to or greater than the predetermined value Dth. Electromagnetic valve driving device that keeps the form during the peak current supply period of FIG. 2 without changing to the hold signal HD (specifically, the electromagnetic valve driving device in which the processing of S120, S130, S210, and S230 in FIG. 2 is not performed) The change in the valve opening by the proportional device is shown. The time ta is the time when the valve opening reaches 100% in the case of comparison, and the time tb is the time when the valve opening reaches 100% in the case of the above embodiment. The difference in ta is the operation response delay of the valve body.

Therefore, in order to suppress such an operation response delay, the above-described embodiment may be modified as follows.
First, the microcomputer 3 determines “NO” last time in S210 of FIG. 2B, and if “YES” is determined this time, the microcomputer 3 determines a predetermined time from the start of one cycle of the drive signal DRx in S230. Until the time Tp elapses, the base signal BAx is not the hold signal HD, but the same period as the hold signal HD and the duty ratio of the initial value α (for example, 90%) larger than the duty ratio of the hold signal HD. A pulse train signal is output.

  If the microcomputer 3 determines “YES” last time in S210 of FIG. 2B and also determines “YES” this time, in S230, the microcomputer 3 performs predetermined processing from the start of one cycle of the drive signal DRx. Until the time Tp elapses, as the base signal BAx, a pulse train signal that becomes high at a duty ratio smaller than the duty ratio of the pulse train signal output in the previous S230 is output as the hold signal HD. However, the duty ratio of the pulse train signal is set within a range equal to or higher than the duty ratio of the hold signal.

  That is, when the determination result of S120 in FIG. 2A changes from a negative determination result (NO) to an affirmative determination result (YES), as shown in an ellipse of a two-dot chain line in FIG. The drive signal DRx in the peak current supply period is changed to a pulse train signal having a duty ratio with an initial value α larger than the duty ratio of the hold signal HD, and the determination result of S120 in FIG. When the determination result is reached (that is, when the determination result is affirmative both in the previous time and this time), the form in the peak current supply period of the drive signal DRx in the next cycle is equal to or higher than the duty ratio of the hold signal HD, and A pulse train signal having a duty ratio smaller than the duty ratio of the pulse train signal in the peak current supply period of the drive signal DRx of the previous cycle is used.

  For this reason, when the determination result of S120 is continuously an affirmative determination result, the duty ratio of the pulse train signal in the peak current supply period of the drive signal DRx is from an initial value α that is larger than the duty ratio of the hold signal HD. The drive signal DRx gradually decreases for each cycle, and approaches the duty ratio of the hold signal HD.

  And according to such a modification, when performing control which makes electromagnetic valve Vx a full open state by making drive duty ratio approach 100% gradually, the valve body of electromagnetic valve Vx is made into an operation completion position ( It can be moved quickly to the fully open position).

  This is because the duty ratio of the pulse train signal in the peak current supply period of the drive signal DRx after the determined drive duty ratio becomes equal to or greater than the predetermined value Dth is greater than the duty ratio of the hold signal HD. For example, “Ip ′” in FIG. 6 indicates the current flowing through the coil Lx of the solenoid valve Vx when the duty ratio of the pulse train signal in the peak current supply period of the drive signal DRx is the initial value α. Ip ′ is smaller than the normal peak current Ip, but larger than the hold current Ih.

From the above, according to this modification, it is possible to achieve both the operation responsiveness of the valve body and the power saving performance in a balanced manner.
In this modification, the pulse train signal in the peak current supply period of the drive signal DRx corresponds to the current suppression pulse train signal. Further, the period of the pulse train signal in the peak current supply period may not be the same as the period of the hold signal HD, but if the period is the same as the period of the hold signal HD, the process for outputting the drive signal DRx It can be simplified.

[Second Modification]
By the way, FIG. 7 shows that in the electromagnetic valve drive device 1 of the above-described embodiment, the drive duty ratio is determined to be equal to or greater than the predetermined value Dth with respect to the drive signal DR1 of the electromagnetic valve V1, and the drive duty with respect to the drive signal DR2 of the electromagnetic valve V2. The ratio is determined to be 0%, and the drive duty ratio is determined to be, for example, 50%, which is less than the predetermined value Dth, for the drive signal DR3 of the solenoid valve V3.

  In this case, the base signal BA1 is not the basic signal form shown in FIG. 1B, but remains the hold signal HD, and the drive duty signal DD1 remains high. Therefore, the drive signal DR1 is the hold signal HD. It becomes the form as it is. The base signal BA2 has the basic signal form shown in FIG. 1B, but the drive duty signal DD2 remains low because the drive duty ratio is 0%, and as a result, the drive signal DR2 also remains low.

  That is, in the situation shown in FIG. 7, the drive signal DR1, which is one of the three drive signals DR1 to DR3, is continuously positively determined in S120 of FIG. As for the signal DR2, the drive duty ratio is determined to be 0% by S110 in FIG. 2A (in other words, the energization time Ton is determined to be 0).

  Here, it is assumed that a request (drive start request) for starting driving of the electromagnetic valve V2 corresponding to the drive signal DR2 occurs in such a situation. This drive start request is generated by another control process performed by the microcomputer 3.

  In this case, as shown in FIG. 8A, the drive signal DR2 is high at the one cycle start timing (time t6) of the drive signal DR2 that comes first after the drive start request of the solenoid valve V2 is generated. However, if the one-cycle start timing of the drive signal DR1 that remains the hold signal HD arrives earlier than the one-cycle start timing of the drive signal DR2, As shown in FIG. 8B, the one cycle start timing of the drive signal DR2 is advanced to the original one cycle start timing (time t5) of the drive signal DR1, and the one cycle start timing (time t5) is advanced. The output of the drive signal DR2 at a high level is started, and the one cycle start timing of the drive signal DR1 may be delayed by a predetermined time Tp.

  In other words, if one cycle start timing of the drive signal DR2 is replaced with one cycle start timing of the drive signal DR1 that is held in the hold signal HD so that the one cycle start timing of the drive signal DR2 is advanced. good.

  By performing such replacement processing, it is possible to improve the drive start responsiveness of the electromagnetic valve V2 corresponding to the drive signal DR2 while preventing an instantaneous decrease in the battery voltage VB. Specifically, the driving of the electromagnetic valve V2 can be started earlier by a predetermined time Tp than in the case of FIG. Since the drive signal DR1 remains a pulse train signal (in this example, the hold signal HD), the drive signal DR2 is output at high at the original one cycle start timing (time t5) of the drive signal DR1. Even if the operation is started, the peak current Ip does not flow through the coils L1 and L2 of the plurality of solenoid valves V1 and V2 at the same time, and the control of the solenoid valve V1 is not hindered.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to such Embodiment at all, Of course, in the range which does not deviate from the summary of this invention, it can implement in a various aspect. .

For example, the solenoid valve to be driven may be other than the solenoid valve for shifting the automatic transmission.
Further, the number of electromagnetic valves may be one or a plurality other than three.
Further, the drive mode of the electromagnetic valve may be a low-side drive mode in which the switching element is disposed on the downstream side of the coil.

  In addition, among the functions of the signal generation circuits 11 to 13 that generate the drive signals DR1 to DR3, the microcomputer 3 may be configured to perform the functions other than the function of converting the high level to 20V. Therefore, if the driving mode of the solenoid valve is the low-side driving mode and the switching elements Tr1 to Tr3 can be turned on by a driving signal for setting the power supply voltage (for example, 5V) of the microcomputer 3 to a high level, the microcomputer 3 The drive signals DR1 to DR3 may be directly output to the switching elements Tr1 to Tr3.

  DESCRIPTION OF SYMBOLS 1 ... Solenoid valve drive device, 2 ... Output driver, 3 ... Microcomputer, 11-13 ... Signal generation circuit, J1-J3 ... Terminal, V1-V3 ... Solenoid valve, L1-L3 ... Coil, Tr1-Tr3 ... Switching element

Claims (6)

A solenoid valve driving device that drives the solenoid valve by turning on and off a switching element provided in series with an energization path that energizes a coil of the solenoid valve, with a drive signal having a predetermined drive cycle time as a cycle,
Determining means for determining an energization time for energizing the coil in one cycle of the current drive signal for each cycle of the drive signal;
A means for outputting the drive signal to the switching element, wherein the one cycle is included in an energization period that is a period from the start of one cycle of the drive signal until the energization time determined by the determining means elapses. Until the peak current supply time for flowing the peak current that can move the valve body of the solenoid valve from the initial position toward the operation completion position from the start time to the coil has passed, A pulse train that maintains the active level for turning on the switching element, and thereafter, the drive signal is at an active level at a predetermined cycle with a cycle shorter than the drive cycle time until the energization period ends. A hold current capable of holding at least the position of the valve body that is smaller than the peak current but has moved from the initial position. The hold current pulse train signal to flow in the coil, is from the energization period ends until one cycle of the driving signal is terminated, the drive signal output means for the drive signal to the inactive level,
A determination unit that determines whether or not a non-energization time that is a remaining time obtained by subtracting the determined energization time from the drive cycle time is equal to or less than a predetermined lower limit value each time the determination unit determines the energization time. When,
If it is determined by the determination means that the non-energization time is equal to or less than the lower limit value, the determined energization time is changed to the drive cycle time, and the drive signal output this time by the drive signal output means Is the hold current pulse train signal from the elapse of the peak current supply time to the start of the next cycle, and the peak current supply time elapses from the start of the next cycle of the drive signal. The current of the drive signal output by the drive signal output means is an active level at a cycle shorter than the drive cycle time and at a predetermined duty ratio equal to or higher than the duty ratio of the hold current pulse train signal. A signal form changing means for changing to a suppression pulse train signal;
With
The lower limit value is a value smaller than a delay time from when the form of the drive signal changes from the hold current pulse train signal to the inactive level until the valve body starts to return to the initial position. ,
A solenoid valve driving device characterized by the above. In the electromagnetic valve drive device according to claim 1,
The pulse train signal for hold current is a pulse train signal that flows, as the hold current, a current that is smaller than the peak current but that can move the valve body toward the operation completion position, to the coil,
A solenoid valve driving device characterized by the above. In the solenoid valve driving device according to claim 1 or 2,
The current suppressing pulse train signal is a pulse train signal having the same cycle and duty ratio as the hold current pulse train signal;
A solenoid valve driving device characterized by the above. In the solenoid valve driving device according to claim 1 or 2,
The signal form changing means includes
When the determination result of the determination unit changes from a negative determination result that the non-energization time is not less than or equal to the lower limit value to an affirmative determination result that the non-energization time is less than or equal to the lower limit value, When the duty ratio of the pulse train signal is set to an initial value larger than the duty ratio of the hold current pulse train signal, and the judgment result of the judgment means continuously becomes the positive judgment result, the current suppression Setting the duty ratio of the pulse train signal to a value that is equal to or greater than the duty ratio of the hold current pulse train signal and smaller than the duty ratio of the current suppression pulse train signal in the drive signal of the previous cycle;
A solenoid valve driving device characterized by the above. In the electromagnetic valve drive device according to any one of claims 1 to 4,
The electromagnetic valve driving device drives a plurality of electromagnetic valves, and for each of the electromagnetic valves, the switching element, the determining means, the driving signal output means, the determining means, and the signal form changing means. With
The start timing of one cycle of each drive signal corresponding to each of the solenoid valves is shifted by a predetermined time longer than the peak current supply time so that the periods during which the drive signals remain at the active level do not overlap each other. That
A solenoid valve driving device characterized by the above. In the electromagnetic valve drive device according to claim 5,
For the specific drive signal that is one of the drive signals, the determination unit continuously determines that the non-energization time is less than or equal to the lower limit value, and is different from the specific drive signal. When a request to start driving of the solenoid valve corresponding to the other drive signal occurs in a situation where the determination means determines the energization period to be 0, the drive signal of the other drive signal If the start timing of one cycle of the specific drive signal arrives earlier than the start timing of one cycle, the start timing of one cycle of the other drive signal is set as the start timing of one cycle of the specific drive signal. Start output at the active level of the other drive signal at the start timing of the one cycle that is earlier
A solenoid valve driving device characterized by the above.

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