JP2014066196A - Solenoid valve driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a response time in cutting electric power supply while reducing power consumption in a driving circuit of a solenoid valve.SOLUTION: A solenoid valve driving device includes a first capacitor C104 supplying electricity to one of terminals of a solenoid valve, a first switch circuit TR118 connected to an earth-side terminal of the solenoid valve, a first diode D122 in which an anode is connected between the earth-side terminal of the solenoid valve and the first switch circuit, a second capacitor C126 for accumulating counter electromotive force energy from the solenoid valve flowing in through the first diode, and a switching circuit network 136, SW130, SW132, D128 switching the connection between the first capacitor and the second capacitor in parallel or in series. The switching circuit network connects the first and second capacitors in parallel, when the electric power is supplied to the solenoid valve, to charge the first and second capacitors, and then connects the first and second capacitors in series to accumulate the counter electromotive force energy in cutting power supply to the solenoid valve, in the second capacitor.

Description

  The present invention relates to a solenoid valve driving device that drives a solenoid valve such as a fuel injection valve of an internal combustion engine.

  A fuel injection valve (injector) that injects fuel into a combustion cylinder of an internal combustion engine such as an engine is generally constituted by an electromagnetic valve that opens and closes a valve with an electromagnet. The fuel injection valve includes a solenoid, a plunger that moves by electromagnetic force generated by energizing the solenoid, and a spring that returns the plunger to a fixed position when the energization to the solenoid is interrupted. This opens and closes an injection valve for introducing fuel supplied at high pressure into the cylinder.

  The fuel injection valve is normally controlled by turning on / off power supply from a battery mounted on the vehicle together with the internal combustion engine, and opened by turning on power to the solenoid, and turned off power to the solenoid. To close the valve.

  In particular, the response time of the fuel injection valve, that is, the delay time from when the energization to the solenoid is turned on or off until the valve actually opens or closes, limits the accuracy of the fuel injection amount to the combustion cylinder. This greatly affects the fuel consumption and emission characteristics of the internal combustion engine. For this reason, in order to improve the response characteristics of the fuel injection valve, for example, a capacitor is charged by a booster circuit that boosts the battery power supply voltage, and when the valve is opened, the solenoid is energized from the capacitor to open the response characteristic when the valve is opened. A fuel injection solenoid drive circuit is known (see Patent Document 1).

  On the other hand, the response characteristic when the valve is closed is how to dissipate the back electromotive force energy generated in the solenoid when the power is off, and one of the solutions is to use a Zener diode as a terminal voltage of the solenoid. Is known (see Patent Document 2).

  FIG. 5 is a diagram illustrating an example of a solenoid valve control circuit that uses a Zener diode to improve response characteristics when the valve is closed. In the following description of the present specification, when referring to a fuel injection valve (injector) as a circuit load or an energization target, such as “energizing the fuel injection valve”, “fuel injection valve” or “injector” The term “means” means a solenoid provided in the fuel injection valve.

The circuit shown in FIG. 5, a boosting circuit 501 for boosting a supply voltage _{V BAT} of the battery, a boosting power source capacitor C502 functioning as a step-up power supply being charged by the step-up circuit 501, an injector from C502 was turned on when the valve opening INJ504 And TR503 for starting energization of the. In parallel with TR503, a TR505 for turning on / off current from the battery to the INJ504 is provided, and a transistor TR506 is provided on the low side (ground side) of the INJ504. The TRs 503, 505, and 506 are each configured by a MOSFET, and ON / OFF of each MOSFET is controlled by the control circuit 508. A Zener diode ZD507 is provided between the drain and gate of the transistor TR506.

  When the valve is opened, the control circuit 508 turns on the TRs 503 and 506, supplies the high voltage of the boost power supply capacitor C502 to the INJ 504, and quickly opens the fuel injection valve. When a predetermined time elapses after the valve is opened, the control circuit 508 turns off the TR 503, starts the ON / OFF control of the TR 505, and holds the valve open state by driving the INJ 504 in pulses. That is, when the TR 505 is on, the battery is energized to the INJ 504 to keep the valve open, and when the TR 505 is off, the back electromotive force generated in the INJ 504 causes a current to flow back to the INJ 504 via the flywheel diode D509. Thus, the valve open state is maintained.

  When the fuel injection period is completed, the control circuit 508 turns off TR505 and TR506 and stops energization to the INJ 504. At this time, a counter electromotive voltage is generated in the INJ 504, and a current flows from the INJ 504 toward the ZD 507. However, since the counter electromotive voltage decreases to the breakdown voltage of the Zener diode ZD 507, the current decrease period is shortened and fuel injection is performed. The valve will close quickly.

  The circuit shown in FIG. 5 can shorten the response time when the valve is opened and closed, but the back electromotive force energy generated in the INJ 504 when the valve is closed is consumed as thermal energy by the current flowing through the ZD 507 and the like. The Rukoto. As a result, the heat generated by the electric circuit increases and the power consumption also increases.

  Therefore, for the purpose of reducing the power consumption of the electric circuit, for example, in Patent Document 3, the boost power supply capacitor is charged by the back electromotive force generated in the fuel injection valve when the valve is closed, and the back electromotive force energy is boosted. An internal combustion engine controller that regenerates to a power supply capacitor is described.

  FIG. 6 is a diagram showing a part of the internal combustion engine control device described in Patent Document 3. As shown in FIG. When starting the fuel injection period, the control circuit 610 turns on TR602 and TR604 to apply a high voltage from the booster circuit 601 to the INJ 605 and quickly opens the valve. After a predetermined time has elapsed, TR602 is turned off, and TR606 is turned on / off to maintain the valve open state. When the fuel injection period ends, TR606 and TR604 are turned off and the energization to INJ 605 is stopped.

  A current flowing in the INJ 605 due to the back electromotive voltage generated after the energization is stopped flows into the booster circuit 601 through the diode D607 and the resistor R608, and is regenerated in the booster circuit 601. Thereby, for example, a boost power supply capacitor (not shown) provided in the output circuit of the booster circuit 601 is charged.

  However, in the circuit of FIG. 6, the fuel injection time, that is, the energization time to the INJ 605, is different when the valve is closed due to the difference in the residual charge amount of the boost power supply capacitor due to the difference in the energization time between the pilot injection and the main injection. As a result of the current decrease rate of the INJ 605 during energy regeneration being different, a situation may occur in which the valve closing response time varies.

  In order to eliminate the difference in the valve closing response time due to such a difference in energization time, Patent Document 4 provides a small-capacity energy regeneration capacitor in addition to the boost power supply capacitor, and the back electromotive force of the fuel injection valve An electromagnetic load driving device is described in which energy is once recovered by the regenerative capacitor and then regenerated to the boost power source capacitor. In this drive unit, all the charge of the regenerative capacitor is given to the boost power supply capacitor until the next valve opening, and when the valve is closed, the residual charge of the regenerative capacitor is always zero, The valve closing response time is kept constant so that the current decrease time of the fuel injection valve at the time of collecting the back electromotive force energy in the capacitor is always constant.

FIG. 7 is a diagram showing a part of the circuit of the electromagnetic load driving device described in Patent Document 4. In FIG. Oscillator 701, inductor L702, transistors TR703,704 and the capacitor C705 is a step-up circuit from the battery voltage _{V BAT,} by turning on / off the TR704 at a constant period by an oscillator 701, C705 is boosted power supply capacitor It is charged to a predetermined high voltage.

  As an initial state before the fuel injection period, TR703 is on, TR704 is off (that is, the boosting operation is stopped), and all other transistors are off. Hereinafter, an operation targeting INJ711 will be described as an example. At the start of the fuel injection period, the control IC 710 turns on TR707 and TR708 and applies the high voltage of the boost power supply capacitor C705 to the injector INJ711 to open the valve. After a predetermined time has elapsed, TR707 is turned off, TR706 is turned on / off, INJ711 is pulse-driven, and the valve open state is maintained. At the same time, on / off of TR704 is started, and charging of C705 discharged by the valve opening operation is started.

  When the fuel injection period ends, the control IC turns off TR706, TR708, and TR703, stops the operation of the oscillator 701, and keeps TR704 on. As a result, the current caused by the back electromotive voltage generated in the INJ 711 flows from the INJ 711 to the small-capacitance capacitor C713 via the diode D712, and the back electromotive force energy is recovered in the C713. At this time, since the boosting power supply capacitor C705 is charged to a certain voltage, the current from the INJ711 flows into the small-capacitance capacitor C713 without passing through the diode D714.

  After a predetermined time sufficient for recovering the back electromotive force energy by the small-capacitance capacitor C713, the control IC turns on TR703 at the same time as turning on TR703. As a result, the low voltage side of the small capacitor C713 is connected to the high voltage side of the boost power supply capacitor C705, and current flows from the high voltage side terminal of the small capacitor C713 to the high voltage side of the boost power supply capacitor C705 via the diode D714. , The back electromotive force energy recovered in C713 is applied to C705, and the regeneration of the back electromotive force energy is completed. Further, after the energy regeneration is completed, the operation of the oscillator 701 is started, the charging of the boost power supply capacitor C705 is resumed for the next valve opening operation, and the charging of C705 is completed, thereby starting the next fuel injection period. I'm ready.

  Since the control device described in Patent Document 3 or 4 described above regenerates the back electromotive force energy generated in the injector when the valve is closed to the boost power source, the power consumed as heat is reduced and the power consumption of the control circuit is reduced. Is reduced. However, in these control devices, the current flowing due to the back electromotive force generated in the injector is determined by the capacity of the capacitor used for recovering the back electromotive force energy and the forward resistance of the diode arranged in series with the capacitor. Since it attenuates with a constant, the response time at the time of valve closing becomes longer compared with the control circuit using the Zener diode shown in FIG.

  In the control circuit described in Patent Document 4, it is necessary to stop the booster circuit (specifically, the on / off operation of TR 704 by the oscillator 701) once when the back electromotive force energy is recovered by the small-capacitance capacitor. The control associated with is complicated. In this control circuit, since the energy regeneration operation from the small-capacitance capacitor to the boost power supply capacitor and the voltage recovery operation (charging operation) of the boost power supply capacitor are performed after the end of the fuel injection period, the fuel injection of INJ711 After the end of the period, for example, TR716 cannot be turned on immediately to start fuel injection by the other fuel injection valves INJ715, and there is another problem that the fuel injection timing of each fuel injection valve is limited. .

JP-A-9-115727 JP-A-7-224708 Japanese Patent No. 4474423 Japanese Patent No. 4103254

  That is, in an apparatus that drives an electromagnetic valve such as a fuel injection valve, it is desired to shorten the response time of the electromagnetic valve when power is cut off while reducing power consumption using simple control.

The present invention is an electromagnetic valve driving device that controls opening and closing of an electromagnetic valve, the first capacitor supplying power to one terminal of the electromagnetic valve, and the other terminal connected to the other terminal of the electromagnetic valve. A first switch circuit that controls opening and closing of the solenoid valve by turning on and off the connection from the ground to the ground, and a first switch having an anode connected between the other terminal of the solenoid valve and the first switch circuit. And a diode. Further, the electromagnetic valve driving device includes a second capacitor that accumulates back electromotive force energy generated in the electromagnetic valve via the first diode, and between the first capacitor and the second capacitor. And a switching network that switches the connections in parallel or in series with each other. In the above configuration, when the first switch circuit is on and the solenoid valve is energized, both the first and second capacitors are charged to the power supply voltage. Until the first diode side terminal of the second capacitor is connected to the power source until the first and second capacitors are connected in parallel to each other, and the first and By connecting the low voltage side terminal of the second capacitor to the high voltage side terminal of the first capacitor while the second capacitor is charged to the voltage of the power source, the first and second Controlled to connect capacitors in series. Further, the second capacitor, when connected in series with the first capacitor, generates back electromotive force energy generated in the electromagnetic valve when the first switch circuit is turned off. When stored through one diode and connected in parallel with the first capacitor by the switching network, the stored back electromotive force energy is regenerated to the first capacitor.
According to another aspect of the present invention, a booster circuit that boosts the voltage of the power supply to charge the first capacitor, and a second power supply that turns on / off power supply from the first capacitor to the one terminal of the solenoid valve. And a third switch circuit for turning on and off power feeding from the power supply to the one terminal of the solenoid valve without going through the boost power supply, and driving the second switch circuit Then, the electromagnetic valve is opened by the power supply from the first capacitor, the third switch circuit is driven, and the open state of the electromagnetic valve is maintained by the power supply from the power source.
According to another aspect of the present invention, the switching network includes the first capacitor and the second capacitor after the first capacitor is discharged toward the solenoid valve by driving the second switch circuit. The first capacitor and the second capacitor are connected in series before the first switch circuit is turned off and the solenoid valve is de-energized. Be controlled.
According to another aspect of the invention, the switching network is between one terminal on the first diode side of the second capacitor and one terminal on the power supply side of the first capacitor. A connection between the fourth switch circuit for turning on and off the connection of the second capacitor, the other terminal facing the one terminal of the second capacitor, and the other terminal facing the one terminal of the first capacitor And a second diode having an anode connected to the other terminal of the second capacitor and a cathode connected to the one terminal of the first capacitor. Is done.
According to another aspect of the invention, the switching network is between one terminal on the first diode side of the second capacitor and one terminal on the power supply side of the first capacitor. A connection between the fourth switch circuit for turning on and off the connection of the second capacitor, the other terminal facing the one terminal of the second capacitor, and the other terminal facing the one terminal of the first capacitor And a sixth switch circuit for turning on / off the connection between the other terminal of the second capacitor and the one terminal of the first capacitor.
According to another aspect of the invention, the solenoid valve is a fuel injection valve that injects fuel into a cylinder of an internal combustion engine.
According to still another aspect of the present invention, the solenoid valve is a plurality of solenoid valves, each solenoid valve is a fuel injection valve, and the plurality of first valves provided for each of the plurality of solenoid valves. A switch circuit and a plurality of the first diodes are operated, and the plurality of first switch circuits are individually driven to operate the electromagnetic valves as fuel injection valves in a fuel injection period that does not overlap each other. Let

  ADVANTAGE OF THE INVENTION According to this invention, in the apparatus which drives electromagnetic valves, such as a fuel injection valve, response time of the said electromagnetic valve at the time of energization can be shortened, aiming at reduction of power consumption using simple control. .

It is an electric circuit diagram which shows the solenoid valve drive device which concerns on one Embodiment of this invention. It is an electric circuit diagram which shows the structure of the switching circuit network used for this electromagnetic valve drive device. It is an electric circuit diagram which shows the example of the other structure of the switching circuit network used for this electromagnetic valve drive device. It is a figure which shows the waveform of each part in the fuel injection period of this solenoid valve drive device. It is a figure which shows the waveform of each part of this solenoid valve drive device when operating two fuel injection valves from which a fuel injection period differs in this solenoid valve drive device. It is a figure which shows an example of the conventional solenoid valve control circuit. It is a figure which shows a part of conventional internal combustion engine control apparatus. It is a figure which shows a part of drive device of the conventional electromagnetic load.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an electric circuit diagram showing a solenoid valve driving apparatus according to an embodiment of the present invention.
The electromagnetic valve driving device 100 controls the operation of a fuel injection valve (injector), which is an electromagnetic valve, provided in an internal combustion engine. FIG. 1 shows an electric circuit of the electromagnetic valve driving device 100, Two fuel injection valves INJ 108 and 110 to be controlled are shown in a connected state.

This electromagnetic valve driving apparatus 100 includes a booster circuit 102 which is powered from a battery power source having a voltage _{V BAT,} a boosted power supply capacitor C104 is charged to a high voltage _{V h} than _{V BAT} by the boost circuit 102, C104 and INJ108 and And a transistor TR106 which is arranged between the INJ110 and turns on / off the current from the C104 to the INJ108 and the INJ110.

  In addition, the solenoid valve driving device 100 includes a transistor TR112 for pulse-driving the INJ108 and INJ110 by direct energization from a battery power supply, and a diode for preventing the boosted voltage Vh from being applied to the TR112 when the TR106 is on. D114. Further, the solenoid valve driving device 100 has a diode D116 for causing the current caused by the counter electromotive force generated in the INJ 108 and INJ 110 to flow back to the INJ 108 and INJ 110 during the energization off period in the pulse driving.

  In addition, the solenoid valve driving device 100 includes transistors TR118 and TR120 arranged between INJ108 and INJ110 and ground (ground), a diode D122 having an anode connected to a connection path between INJ108 and TR118, INJ110, A diode D124 having an anode connected to the connection path with TR120, and a capacitor C126 for energy regeneration that stores back electromotive force energy generated in INJ108 and INJ110 via D122 and D124, respectively. Here, for the following explanation, a point where the cathodes of D122 and D124 and one end of C126 are connected is a point P, and a point on the path connected to a terminal on the side opposite to the point P side of C126 is a point Q. Called.

  The solenoid valve driving device 100 also includes a switching circuit network 136 that switches the connection relationship between the boost power supply capacitor C104 and the regeneration capacitor C126 in parallel or in series. The switching circuit network 136 includes switches SW130 and SW132, It is comprised by the diode D128.

  Furthermore, the solenoid valve driving apparatus 100 includes a control circuit 134 that controls the operations of the transistors TR106, 112, 118, and 120 and the operations of the switches SW130 and SW132. In the present embodiment, the control circuit 134 is a part of an ECU (Electronic Control Unit) that manages and controls the operation of the internal combustion engine, and the electromagnetic valve driving device 100 is incorporated in the ECU.

  In the present embodiment, the boost power supply capacitor C104 corresponds to the first capacitor, the transistors TR118 and 120 correspond to the first switch circuit, the diodes D122 and 124 correspond to the first diode, and the regeneration capacitor. C126 corresponds to the second capacitor. The transistor TR106 corresponds to a second switch circuit, and the transistor TR112 corresponds to a third switch circuit.

  The transistors TR106, 112, 118, and 120 operate as switches that are turned on and off by the control circuit 134. In this embodiment, the transistors TR106 and TR112 are P-channel MOSFETs, and TR118 and TR120 are N-channel MOSFETs. . However, the present invention is not limited to this, and the TR 106, 112, 118, 120 may be replaced with other types of transistors, for example, other types of MOSFETs, FETs other than MOSFETs, switching transistors, switching devices, or switching devices. An IC (Integrated Circuit) can also be used.

FIG. 2A is a diagram showing the switching network 136 and its peripheral circuit elements extracted from the circuit diagram of FIG. In FIG. 2A, the boosting circuit 102, are equivalently indicated as a battery supplies a boosted voltage V _h. The switching network 136 is provided between a point P side terminal (hereinafter referred to as “P side terminal”) of the regeneration capacitor C126 and a power supply side terminal (terminal to which the booster circuit 102 is connected) of the booster power supply capacitor C104. , A switch SW130 disposed on the C126, a diode D128 having an anode connected to a point Q side terminal (hereinafter referred to as "Q side terminal") of C126 and a cathode connected to a power supply side terminal of C104, and a Q side terminal of C126 And a switch SW132 disposed between the ground and the ground.

  Here, the switches SW 130 and 132 can be configured by switching elements, switching devices, or switching ICs configured by semiconductor devices such as FETs and bipolar transistors.

  In this embodiment, SW130 corresponds to a fourth switch circuit, SW132 corresponds to a fifth switch circuit, and D128 corresponds to a second diode.

SW130 and SW132 are normally open switches that are in a non-conducting state (off state) in a non-driving state. When SW130 and SW132 are both brought into conduction becomes the driving state (on state), Q terminal of C126 is connected to the ground, since the possible reverse voltage _{V h} is applied to D128, C126 and C104 are substantially Connected in parallel. Thus, C 104 and C126 are both charged to the inter-terminal voltage is _{V h.} The diodes D122 and D124 block the outflow of current from the C104, C126 and the booster circuit 102 to the TR 118 and TR 120.

When both SW 130 and SW 132 are in a non-driven state and turned off, the Q side terminal of C126 is connected to the power source side terminal of C104 via D128, and C104 and C126 are connected in series. Thus, the potential of the Q terminal of C126, pulled up to the potential _{V h} of C104 line terminal through a D128, the potential of the P-side terminal of C126 becomes 2V _h.

  In the switching network 136 used in the embodiment, the power supply side terminal of C104 and the Q side terminal of C126 are connected via D128. However, the present invention is not limited to this, and the switching shown in FIG. As in the circuit network 136 ′, a normally closed switch SW202 that is turned on in the non-driven state can be used instead of D128. Note that SW 202 corresponds to a sixth switch circuit.

In the case of switching network 136 'is, if all the driving state SW130,132,202, SW 130 and SW132 are turned on, SW202 is turned off, until the voltage _{V h} is the C104 and C126 are parallel state is charged, if any SW130,132,202 undriven state, SW 130 and SW132 are turned off, SW202 and the C104 and C126 are connected in series in the oN state, the potential of point P and 2V _h Become.

  Next, the operation of the solenoid valve driving apparatus 100 will be described with reference to the waveform diagram shown in FIG. FIG. 3 is a diagram illustrating waveforms of the respective parts of the solenoid valve driving apparatus 100 during the fuel injection period. The waveform (a) is a current flowing through the INJ 108, the waveform (b) is a voltage between terminals of the C104, and the waveform (c) is C126. The time change of the voltage between terminals is shown.

Further, the waveform (d) in FIG. 3 is a gate-source voltage V _GS1 for controlling ON / OFF between the source and the drain of the TR 118, and the waveform (e) is a gate for controlling ON / OFF between the source and the drain of the TR 106. The source voltage V _GS2 , the waveform (f) is a control signal for controlling on / off of the SW 130, the waveform (g) is a control signal for controlling the on / off of the SW 132, and the waveform (h) is between the source and drain of the TR 112. The time change of the gate-source voltage V _GS3 for controlling on / off of the signal is shown.

In FIG. 3, before the start of the fuel injection period, the boost power supply capacitor C104 is charged to the voltage V _h (> V _BAT ) determined by the boost circuit 102, and the regeneration side capacitor C126 has a voltage V _{re at the} P-side terminal. It is assumed that the battery is charged until (> V _h ). Incidentally, V _re, due same operations as those shown below are C126 inter-terminal voltage after being charged by the counter electromotive force of INJ108 when immediately before the fuel injection period.

Since TR118 is an N-channel MOSFET, the source-drain is turned on when V _GS1 is a positive voltage, and the source-drain is turned off when V _GS1 is 0V. Since TR 106 is a P-channel MOSFET, the source-drain is turned on when V _GS2 is a negative voltage, and the source-drain is turned off when V _GS2 is 0V. In addition, in the waveforms (d) to (h) shown in FIG. 3, the open / closed states of the corresponding transistors and switches (that is, “ON” or “OFF”) are described according to the level of each waveform. .

Control circuit 134, applied at time T1 in FIG. 3, the TR106 and TR118 in order to start the fuel injection period on (waveform (d) and (e)), the high voltage _{V h} from the booster power supply capacitor C104 to INJ108 To do. Due to this high voltage, the fuel injection valve corresponding to INJ 108 opens quickly and the fuel injection period starts. At this time, the energization current (waveform (a)) of the INJ 108 increases with a time constant determined by the capacitance of the C104, the inductance of the INJ 108, the resistance between the source and drain of the TR 106, and the like.

  Thereafter, the control circuit 134 turns off the TR 106 (waveform (e)) at a time T2 when a predetermined time sufficient for the valve opening operation has elapsed and the discharge of C104 is almost completed. The energization current of the INJ 108 is circulated through the diode D116 by the counter electromotive voltage generated in the INJ 108 and gradually decreases (waveform (a)). In this state, one end of the INJ 108 is grounded by the TR 118, and a reverse voltage is applied to the D 122 and D 124, so that the current caused by the counter electromotive voltage generated in the INJ 108 does not flow into the C 126. .

  At time T3 immediately after turning off TR106, control circuit 134 turns on SW130 and SW132 (waveforms (f) and (g)). As a result, the regenerative capacitor C126 is connected in parallel with the boost power supply capacitor C104, and the charge of the regenerative capacitor C126 flows to C104 and is stored in the regenerative capacitor C126 at the end of the previous fuel injection period. The back electromotive force energy of the INJ 108 is regenerated in the boost power supply capacitor C104 (waveforms (b) and (c)).

In the charge transfer is completed time T4 from the regenerative capacitor C126 to boost power capacitor C104, the voltage between the terminals of the C126 and C104 becomes the same voltage, then rises together to the voltage _{V h} by charging by the step-up circuit 102 ( Waveforms (b) and (c)). Then, after time T6 when the voltage between the terminals of the C126 and C104 reaches _{V h,} at time T7 which is sufficient predetermined time has elapsed charging operation from the time T4 C104 and C126, the control circuit 134, SW 130 and 132 Turn off. Accordingly, the potential of the P-side terminals of the regenerative capacitor C126 is ready to recover 2V _h, and the back EMF energy INJ108.

On the other hand, after time T2 when TR106 is turned off, the energization current of INJ 108 continues to decrease (waveform (a)). At time T5 when the energization current of INJ 108 decreases to a predetermined value, control circuit 134 starts on / off control of TR 112 (waveform (h)), and pulse-drives INJ 108 until time T8 when the fuel injection period ends. By doing so, the valve open state is maintained. In this pulse drive, when the TR 112 is on, the battery power supply voltage V _BAT is applied to the INJ 108 to maintain the valve open state. When the TR 112 is off, the reverse electromotive voltage generated at the INJ 108 causes the diode D 116 to pass through. Then, the current is returned to the INJ 108, so that the valve open state is maintained. For this reason, the energization current of the INJ 108 during the period from time T5 to T8 has a waveform that periodically fluctuates in a sawtooth shape (waveform (a)).

  Thereafter, at time T8 when the fuel injection period ends, the control circuit 134 turns off the transistors TR118 and TR112 and stops energization to the INJ 108 (waveforms (d) and (h)). Due to this energization stop, a counter electromotive voltage is generated in the INJ 108, and the TR 118 is turned off, so the potential at the TR 118 side terminal of the INJ 108 rises all at once.

However, since the potential of the P-terminal of C126 is a 2V _h, becomes the diode D122 is turned on when the potential of the TR118 terminal of INJ108 exceeds 2V _h, conversely C126 current flows to C126 from INJ108 The electromotive energy is recovered. In other words, the potential of the TR118 terminal of INJ108 is clamped at 2V _h, back EMF energy INJ108 to be increased beyond the 2V _h is recovered accumulated immediately regenerative capacitor C126. As a result, the current flowing through the INJ 108 decreases rapidly, and the response time when the valve is closed is shortened. More precisely, since C126 is charged when the counter electromotive force energy is recovered, the potential of the P-side terminal of C126 rises from 2 V _h to V _h + V _re (> 2 V _h ) (waveform (c)), and therefore , the potential of the TR118 terminal of INJ108 is clamped in a range of _{[2V h ~V h + V re} ].

Recovery of the back EMF energy INJ108 is completed by C126, at time T9 the terminal voltage of the C126 rises to _{V re,} fuel injection period one cycle of the control operation in the electromagnetic valve drive apparatus 100 is completed. That is, at time T9, the solenoid valve driving apparatus 100 is in the same state as the initial state at time T1 when the fuel injection period is started, and returns to a state where a new fuel injection period can be started.

  With the above operation, the electromagnetic valve driving device 100 efficiently regenerates the back electromotive force energy generated in the INJ 108 when the valve is closed without consuming it as heat, and opens the valve during the subsequent fuel injection period. Can be used. For this reason, the solenoid valve driving device 100 can reduce the heat generation amount of the circuit with low power consumption, simplify the heat dissipation structure of the ECU in which the solenoid valve driving device 100 is incorporated, and reduce the size of the ECU. it can.

In addition, the solenoid valve driving device 100 connects the regenerative capacitor C126 and the boost power supply capacitor C104 in parallel by the switching circuit network 136 before the valve is closed and charges them together. After charging, the C126 is connected in series with the C104. the potential of the high voltage side terminal of the regenerative capacitor C126 may have been raised to 2V _h. Thus, the electromagnetic valve driving apparatus 100, at the time of closing can be operated as a zener diode to diode D122, thereby recovering back EMF energy INJ108 to be increased beyond the voltage 2V _h to C126 INJ108 Can be quickly reduced, and the closing time of the fuel injection valve corresponding to INJ108 can be shortened.

  Furthermore, since the solenoid valve driving apparatus 100 can perform the above-described operation without requiring operation control for the booster circuit 102, the control associated with energy regeneration can be simplified.

  In addition, the solenoid valve driving device 100 can be controlled to inject fuel in the INJ 108 and INJ 110 connected in parallel at the same timing, and can also be operated individually in a range where the fuel injection periods do not overlap. That is, for a plurality of injectors controlled so that the fuel injection periods do not overlap, the plurality of injectors can be individually controlled using the electromagnetic valve driving device 100 in common.

  FIG. 4 shows a solenoid valve driving apparatus in the case where the INJ 108 and INJ 110 connected in parallel are individually controlled at a timing at which the fuel injection periods do not overlap with one solenoid valve driving apparatus 100 in the configuration shown in FIG. FIG. 4 is a diagram illustrating an example of waveforms of respective units in 100.

In FIG. 4, waveforms (a1) and (d1) show changes in the energization current of INJ 108 and the gate-source voltage V _GS1 of TR 118, respectively, as in waveforms (a) and (d) in FIG. . Waveforms (b), (c), (e), (f), and (g) are the same as in FIG. 3, respectively, the voltage between terminals of C104, the voltage between terminals of C126, and the gate / source of transistor TR106. An inter-voltage V _GS2 , a control signal for the switch SW130, and a control signal for the switch SW132 are shown. However, unlike FIG. 3, FIG. 4 shows the time change of the energization current of the INJ 110 in the waveform (a2), and between the gate and source of the transistor TR120 arranged between the INJ 110 and the ground in the waveform (d2). A time change of the voltage V _GS4 is shown.

  The operation at times T1 to T9 shown in FIG. 4 is the same as the operation described with reference to FIG. 3 described above, and the description of FIG. The operation from time T1 'to time T9' following time T1 to T9 is as follows: TRJ is turned on (waveform (d2)) instead of TR118 (waveform (d1)), and INJ110 is substituted for INJ108 (waveform (a1)). Is the same as the operation at the times T1 to T9 except that the operation is performed (waveform (a2)).

  That is, whether to operate INJ108 or INJ110 is controlled by whether TR118 or TR120 is turned on, and other transistors and switches may simply repeat the same operations as those at times T1 to T9. The changes in the terminal voltages of the capacitors C104 and C126 are the same as the changes at the times T1 to T9.

  In particular, the electromagnetic valve drive device 100 is described in Patent Document 4 because the energy regeneration operation from the regeneration capacitor C126 to the boost power supply capacitor C104 and the charge operation of the boost power supply capacitor C104 are completed within the fuel injection period. Unlike the apparatus, when the fuel injection period in one injector is completed and the energization current of the injector becomes zero, the fuel injection period of another injector can be started immediately.

  In the present embodiment, the electromagnetic valve driving device 100 has been described as driving a fuel injection valve of an internal combustion engine. However, the driving target of the electromagnetic valve driving device 100 is not limited to this, and flow control of fluid, gas, or the like is performed. Various solenoid valves can be used.

  As described above, in the solenoid valve drive device according to the present embodiment, the switching circuit network that changes the connection state between the regeneration capacitor and the boost power supply capacitor is used, and the regeneration capacitor is boosted before the end of the fuel injection period. Charge to the power supply voltage, and at the end of the fuel injection period, connect the regenerative capacitor in series with the boost power supply capacitor, and clamp the back electromotive force of the injector to almost twice the voltage of the boost power supply. The back electromotive force energy that is going to rise is immediately collected in the regenerative capacitor. Thereby, this electromagnetic valve drive device can shorten the response time at the time of valve closing by speeding up the current decrease speed of the injector at the time of energization interruption, reducing power consumption by regeneration operation of counter electromotive force energy.

  DESCRIPTION OF SYMBOLS 100 ... Solenoid valve drive device, 102 ... Boost circuit, 134 ... Control circuit, C104 ... Boost power supply capacitor, TR106, TR112, TR118, TR120 ... Transistor, INJ108, INJ110 ... Injector D114, D116, D122, D124 ... diode, C126 ... regenerative capacitor, SW130, SW132, SW202 ... switch, 136 ... switching circuit network.

Claims (7)

A solenoid valve driving device for controlling opening and closing of a solenoid valve,
A first capacitor for supplying power to one terminal of the solenoid valve;
A first switch circuit connected to the other terminal of the electromagnetic valve, for controlling the opening and closing of the electromagnetic valve by turning on and off the connection from the other terminal to the ground;
A first diode having an anode connected between the other terminal of the solenoid valve and the first switch circuit;
A second capacitor for accumulating back electromotive force energy generated in the solenoid valve via the first diode;
A switching network that switches a connection between the first capacitor and the second capacitor in parallel or in series with each other;
With
The switching network is:
When the first switch circuit is in an ON state and the solenoid valve is energized, the first capacitor and the second capacitor are charged until the first and second capacitors are charged to the power supply voltage. Controlled so that the first and second capacitors are connected in parallel with each other such that one diode side terminal is connected to the power source; and
By connecting the low voltage side terminal of the second capacitor to the high voltage side terminal of the first capacitor in a state where the first and second capacitors are charged to the voltage of the power supply, the first capacitor And a second capacitor connected in series,
The second capacitor is:
In the state connected in series with the first capacitor, the back electromotive force energy generated in the solenoid valve when the first switch circuit transits off is stored through the first diode, And,
Regenerating the accumulated back electromotive force energy to the first capacitor when connected in parallel with the first capacitor by the switching network;
Solenoid valve drive device. In the solenoid valve drive device according to claim 1,
A booster circuit that boosts the voltage of the power supply to charge the first capacitor;
A second switch circuit for turning on and off the power supply from the first capacitor to the one terminal of the solenoid valve;
A third switch circuit for turning on / off power feeding from the power source to the one terminal of the solenoid valve without going through the boost power source;
With
Driving the second switch circuit to open the solenoid valve by power feeding from the first capacitor, driving the third switch circuit to turn the solenoid valve open by power feeding from the power source Hold,
Solenoid valve drive device. In the electromagnetic valve driving device according to claim 2,
The switching network is:
Controlled to connect the first capacitor and the second capacitor in parallel after the first capacitor is discharged toward the solenoid valve by driving the second switch circuit; and
Before the energization to the solenoid valve is cut off by the first switch circuit, the first capacitor and the second capacitor are controlled to be connected in series.
Solenoid valve drive device. In the electromagnetic valve driving device according to claim 1,
The switching network includes a fourth switch that turns on and off a connection between one terminal of the second capacitor on the first diode side and one terminal of the first capacitor on the power supply side. A fifth switch circuit for turning on and off a connection between the circuit and another terminal facing the one terminal of the second capacitor and another terminal facing the one terminal of the first capacitor; And a second diode having an anode connected to the other terminal of the second capacitor and a cathode connected to the one terminal of the first capacitor. In the electromagnetic valve driving device according to claim 1,
The switching network includes a fourth switch for turning on and off a connection between the one terminal on the first diode side of the second capacitor and the one terminal on the power supply side of the first capacitor. A fifth switch circuit for turning on and off a connection between the circuit and another terminal facing the one terminal of the second capacitor and another terminal facing the one terminal of the first capacitor; And a sixth switch circuit for turning on and off the connection between the other terminal of the second capacitor and the one terminal of the first capacitor. The electromagnetic valve driving device according to claim 1,
The solenoid valve is a fuel injection valve that injects fuel into a cylinder of an internal combustion engine.
Solenoid valve drive device. The electromagnetic valve driving device according to claim 1,
The solenoid valve is a plurality of solenoid valves, and each solenoid valve is a fuel injection valve,
A plurality of the first switch circuits and a plurality of the first diodes provided respectively for the plurality of solenoid valves;
By operating each of the plurality of first switch circuits individually, the solenoid valves that are fuel injection valves are operated in a fuel injection period that does not overlap each other.
Solenoid valve drive device.

Images