JPH1182128A - Driving device for solenoid type fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a lowering of responsiveness of a fuel injection valve and in its turn a lowering of a fuel flow characteristic with simple constitution and at a low cost even in case of battery voltage being lowered. SOLUTION: Before the rise of a fuel injection signal, a transistor Tr1 is turned on to start preliminary current application to a holding coil so as to generate auxiliary attracting energy. At the time of starting fuel injection, a transistor Tr2 is turned on to start current application to an open coil so as to rapidly generate attracting energy superposed on the auxiliary attracting energy. A needle is therefore pulled up with large attracting force by attracting energy from both coils, and a valve is opened in high response. As a result of applying a preliminary current to the holding coil, auxiliary attracting force of attracting the needle is already generated at the time of starting fuel injection. Accordingly, even in case of battery voltage being lowered, a lowering of valve opening responsiveness caused by a lowering of battery voltage can be suppressed with simple, low-cost constitution compared with conventional constitution of applying a current simultaneously to two coils at the time of starting to open the valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for an electromagnetic (solenoid) fuel injection valve.

[0002]

2. Description of the Related Art For example, a driving apparatus for an electromagnetic fuel injection valve used in a conventional internal combustion engine is disclosed in Japanese Unexamined Patent Publication No. 3-275.
957 and JP-A-8-326620. JP-A-3-275957
The driving device for an electromagnetic fuel injection valve disclosed in Japanese Patent Application Laid-Open No. H10-209400 has a configuration as shown in FIG. 6 and operates roughly as follows to improve the responsiveness of the fuel injection valve.

That is, in the early stage of the valve opening, both the transistor TR1 and the transistor TR2 are turned ON, and the DC-
A relatively large valve-opening current consisting of a discharge current I1 from a capacitor (high-voltage circuit) in the DC converter and a current I2 from a battery is supplied to a fuel injection valve coil (solenoid) to improve valve-opening responsiveness. .

In a subsequent holding period (a period during which the valve is opened), while the transistor TR1 is turned off, the transistor TR1 is turned off based on the current detection result of the current detection circuit.
2 (ON / OFF) and applying the battery voltage discontinuously, a relatively small holding current necessary for maintaining the fuel injector open state is provided by the fuel injector coil. To supply.

When the valve is closed, a back electromotive force is generated by a back electromotive absorption circuit by closing a transistor TR3 provided on the downstream side of the fuel injection valve coil, thereby quickly closing the fuel injection valve. To terminate the injection. Further, the one disclosed in Japanese Patent Application Laid-Open No. 8-326620 is provided with a configuration as shown in FIG. 7 and operates roughly as follows to improve the responsiveness of the fuel injection valve.

That is, in the initial stage of valve opening, both the coil A and the coil B are energized from the battery power source to increase the magnetic attraction force for opening the valve, thereby quickly pulling up the valve body, thereby increasing the valve opening responsiveness. Enhance. In the subsequent holding period, only the coil B is energized from the battery power source to generate a magnetic attraction force necessary to hold the valve body in the valve open state (valve open position).

[0007] In the valve closing period, the power supply to the coil B is stopped, whereby the fuel injection valve is closed immediately, and the injection is terminated.

[0008]

However, the technique disclosed in Japanese Patent Laid-Open Publication No. 3-275957 requires a high-voltage circuit (high-voltage generating circuit), which may increase the product cost. is there. Also, since the control logic is relatively complicated, the configuration of the control circuit is complicated,
There is a fear that the product cost will increase.

[0009] In the device disclosed in JP-A-8-326620, since the two coils are energized at the same time, the rising of the current largely depends on the battery voltage. There is a possibility that the characteristics of the fuel greatly change and stable flow characteristics of the fuel cannot be obtained. The present invention has been made in view of such a conventional situation, and can improve the responsiveness of the fuel injection valve while having a simple configuration and low cost, and can operate the fuel injection valve even when the battery voltage decreases. An object of the present invention is to provide a drive device for an electromagnetic fuel injection valve, which is capable of suppressing a decrease in fuel flow characteristics as well as responsiveness.

[0010]

According to the present invention, as shown in FIG. 1, at least two coils are provided, and these coils are supplied from a battery power supply to the coils based on a fuel injection start command. After energizing for a predetermined period to generate a relatively large electromagnetic attraction force and lifting the valve body by the relatively large magnetic attraction force, energization of at least one coil is stopped and a fuel injection stop command is input. Until
In a drive device for an electromagnetic fuel injection valve that maintains a lift amount of a valve body at a predetermined value with a relatively small magnetic attraction force,
During a predetermined pre-energization period before a fuel injection start command is input, at least one of the coils includes pre-energization means for pre-energizing via a battery power source in a range where the valve body does not lift. did.

According to this structure, the valve body can be lifted with a relatively large magnetic attraction force in the early stage of valve opening, so that a highly responsive valve opening characteristic can be achieved and a relatively small magnetic attraction force (current). The lift state of the valve body can be maintained (maintained), so that reduction of power consumption and the like can be promoted, and at least one coil is pre-energized. By this time, an auxiliary suction force for sucking the valve element can be generated in advance.

For this reason, when the battery voltage is normal, the valve can be opened with high response as in the prior art, and
Even if the battery voltage drops, for example, valve opening responsiveness can be maintained higher than in the conventional case where a plurality of coils are simultaneously energized for the first time at the start of valve opening. That is, according to the present invention, since the responsiveness of the fuel injection valve can be increased,
The region where the fuel injection amount is obtained linearly with respect to the pulse width (linear region) can be expanded to the low injection amount region (short pulse width) side, and the valve opening responsiveness even when the battery voltage decreases Can be kept high, so that the linear region can be minimized from being reduced in the direction of the high injection amount region (long pulse width).

Further, since the effect of the battery power supply voltage drop can be suppressed without providing a high voltage circuit for improving the responsiveness of the fuel injection valve, the product cost can be reduced as compared with the case where a high voltage circuit is required. can do. Further, since the control logic can be simplified as compared with the case where a high-voltage circuit or the like is provided, the configuration of the control circuit can be simplified, and the product cost can be reduced.

According to the second aspect of the present invention, the coil pre-energized by the pre-energizing means is set to have higher resistance and higher inductance than other coils. As described above, the coil to be pre-energized has a high resistance (for example, 10
Ω) ・ High inductance (large number of turns)
The following operational effects can be obtained.

That is, when pre-energizing a low-resistance, low-inductance coil, the rise of current is fast, and if complicated current control or the like is not performed, there is a high possibility that the valve will open immediately after energization is started. It is difficult to generate and maintain the auxiliary suction energy before the start of valve opening.

However, the coil to be pre-energized is
If the resistance is high and the inductance is high, the rising speed of the current is slow. Therefore, even if complicated current control is not performed (only by supplying power from the battery power source), the auxiliary suction energy is generated well before the valve opening starts. It can be maintained. According to the third aspect of the present invention, after the valve element is lifted by the relatively large magnetic attraction force, the coil that is de-energized is lower in resistance and inductance than the coil that is not de-energized until a fuel injection stop command is issued. Was set to.

With this arrangement, the current rises quickly, and the attraction required for opening the valve can be quickly generated, and the auxiliary attraction generated by pre-energizing the coil or the like according to the second aspect of the present invention. The valve opening period can be shortened by the synergistic effect. According to the fourth aspect of the present invention, the coil pre-energized by the pre-energizing means is set to have higher resistance and higher inductance than the other coils, and the valve body is lifted by the relatively large magnetic attraction force. rear,
It is used as a coil that does not stop power supply until a fuel injection stop command is issued.

With this configuration, since the coil to be pre-energized is made of high resistance and high inductance, the rising speed of the current can be reduced, so that the valve opening can be started well without complicated current control or the like. Auxiliary suction energy can be generated and maintained before, so that good valve opening characteristics can be achieved regardless of the battery voltage or the like.

Further, the lift amount of the valve body can be maintained at a predetermined value (maintained in an open state) by direct driving (only energization) by a battery power source, so that the valve body can be opened by a coil having low resistance and low inductance. Compared to maintaining the valve state,
It is possible to eliminate the need for complicated current control or the like for keeping the valve body in the open state while suppressing problems such as power consumption and heat generation. Therefore, a complicated control circuit or the like is not required, and the configuration can be simplified.

Furthermore, the valve element can be held in the open state with a small current as compared with the conventional method in which the valve element is held in the open state by using a coil having low resistance and low inductance. With the configuration, current consumption can be reduced. In addition, since the radiation noise is reduced due to the reduction of the current consumption, it becomes possible to eliminate the need for a shield line or the like.

Further, by reducing the current consumption, it is possible to suppress the heat generation of the drive circuit (for example, a transistor or the like) itself and also the heat generation of the hold coil, thereby improving the durability and reliability of the device. Can be improved. Furthermore, since the coil to be pre-energized is continuously energized and the valve body is held in the valve open state, it is possible to eliminate the switching control of the coil to be used while achieving the above-described various effects. It is possible to obtain a good holding characteristic of the valve element without a switching step and the like, and it is not necessary to provide a circuit and the like for the switching control.

According to a fifth aspect of the present invention, the apparatus further includes a pre-energization period setting changing means for changing the start and the length of the pre-energization period based on the battery power supply voltage. According to such a configuration, for example, even when the battery power supply voltage drops, the auxiliary suction force can be maintained at the same level as in the normal state, so that the fuel injection valve can be opened even more reliably while maintaining the maximum responsiveness. Can be valved. Further, in combination with the invention described in claim 6, since the responsiveness of the fuel injection valve can be maintained substantially constant even when the battery power supply voltage changes, the effect of the battery voltage change on the fuel injection amount can be maintained. Can be eliminated as much as possible.

According to a sixth aspect of the present invention, the apparatus includes a predetermined period setting changing means for changing the start or the length of the predetermined period based on the battery power supply voltage. With this configuration, for example, even when the battery power supply voltage decreases, the magnetic attraction force in the initial stage of valve opening can be maintained at the same level as in a normal state, so that the fuel injection valve responds even when the battery power supply voltage changes. Therefore, the effect of the battery voltage change on the fuel injection amount can be eliminated as much as possible. Further, in combination with the invention described in claim 5, it is possible to further eliminate the influence of the battery voltage change on the fuel injection amount.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
Description will be given based on the attached drawings. As shown in FIG. 2, a drive device 1 for an electromagnetic (solenoid) fuel injection valve (injector) according to a first embodiment of the present invention includes two coils 3 in a magnetic circuit 2 of the fuel injection valve. 4 is provided.

Here, the coil 3 is a hold coil (HOL
D COIL), and functions as a coil for holding the needle (valve element) 5 in the valve-open state (the state in which the needle 5 is pulled up by a predetermined amount). In the present embodiment, the hold coil (HOLD COIL) 3 has a high resistance (for example, about 10Ω) and a high inductance (large number of turns).
It is composed of

On the other hand, the coil 4 is an open coil (OPEN
COIL), which is a coil for quickly lifting (pulling up) the needle 5 from the valve-closed state to the valve-opened state in the early stage of the valve opening. The open coil (OPEN COI
L) 4 is configured with low resistance and low inductance (small number of turns) in the present embodiment.

The hold coil 3 is energized or de-energized from a battery power source by an operation state (ON / OFF) switching control of the transistor Tr1. The open coil 4 is configured to be energized or de-energized from a battery power source by an operation state (ON / OFF) switching control of the transistor Tr2.

The transistor Tr1 and the transistor Tr2 are provided in an engine control unit (ECU).
In the control circuit 7, the operation state (ON / OFF) is controlled by a control circuit 7 based on a fuel injection signal (pulse signal) set based on an operation state (intake air flow rate, engine rotation speed, water temperature, target air-fuel ratio, etc.). (Switched).

By the way, the control circuit 7 according to this embodiment
Performs the control as shown in the timing chart of FIG. 3, for example. Note that the control circuit 7 functions as the preliminary energizing means according to the present invention. That is, a fuel injection signal (pulse signal) set based on an operation state in an engine control unit (ECU).
Before the rise (fuel injection start command; fuel injection start timing; valve opening start), the transistor Tr1 is turned on to start pre-energization of the hold coil 3, and the needle (valve element) 5 of the fuel injection valve is illustrated. This generates auxiliary suction energy that contributes to opening (lifting) the valve against the elastic force of the elastic body that biases the valve seat portion (seat portion) to be closed.

The control circuit 7 controls (sets) the pre-energization time (period) so that the needle (valve element) 5 of the fuel injection valve is not opened (lifted) by the auxiliary suction energy. I do. Thus, to the hold coil 3,
The pre-energization is performed before the rise of the fuel injection signal (pulse signal) because the hold coil 3 has a high resistance and a high inductance as described above, and the current rise speed is slower than that of the open coil 4. In order to generate a large magnetic attraction force with the two coils of the hold coil 3 and the open coil 4 in the early stage of opening the valve and to improve the valve opening response, the hold coil 3 is energized in advance (preliminary energization). It is necessary.

At the start of fuel injection (at the start of valve opening, at the rise of the fuel injection signal, at the beginning of valve opening), the transistor T
When r2 is turned on, the energization of the open coil 4 is also started, and the suction energy for opening the valve is superimposed on the above-mentioned auxiliary suction energy to quickly generate the suction energy. As a result, the needle (valve element) 5 is pulled up (sucked) with a large suction force by the suction energy from both coils in the initial stage of valve opening, and thus the valve is opened with high response.

Since the open coil 4 has a low resistance and a low inductance as described above, the rise speed of the current is high, so that the open coil 4 is used at the start of fuel injection (at the start of valve opening, at the time of rise of the fuel injection signal). In addition, energization is started. By the way, in the present embodiment, as a result of the pre-energization of the hold coil 3, when the fuel injection starts (when the valve opening starts,
At the time of the rise of the fuel injection signal), an auxiliary suction force for suctioning the needle (valve element) 5 has already been generated. As compared with the case where two coils are energized simultaneously, it is possible to suppress a decrease in valve opening response due to a decrease in battery voltage.

The effect of the pre-energization can be achieved even when two coils having the same specifications are provided. Therefore, the present invention provides the configuration of the first embodiment (the configuration having different specifications). However, the present invention is not limited to this. Thereafter, when the valve opening operation is completed (when the needle 5 is lifted by a predetermined amount from the valve closed state), the transistor Tr2 is turned off.
FF is performed to stop energizing the open coil 4 and energizing only the hold coil 3.

Since the hold coil 3 is set to have a high resistance so that the needle 5 can be held open by direct drive by a battery, a current for holding the needle 5 in an open state is maintained. Control and the like can be made unnecessary. Therefore, a complicated control circuit or the like is not required, and the configuration can be simplified. That is, the needle 5 is over-current (power consumption or heat generation) using a coil configured with low resistance and low inductance to improve the responsiveness as in the related art (disclosed in Japanese Patent Application Laid-Open No. 8-326620). And the like, it is necessary to control the current when maintaining the valve open state while suppressing such a need. However, according to the present embodiment, such a necessity can be eliminated.

When the valve is closed (rise of the fuel injection signal), the transistor Tr1 is turned off, a back electromotive force is generated by the back electromotive absorption circuit 6 shown in FIG. 2, and the needle (valve element) 5 is biased to close. In combination with the elastic force of the elastic body, the needle (valve element) 5 is immediately seated on the seat portion (closed), and the injection is terminated. That is, when the valve is closed, the responsiveness of the valve closing operation can be further increased by the back electromotive absorption circuit 6 as compared with the case where the valve is closed only by the elastic force of the elastic body.

As described above, according to the present embodiment, at least two coils are provided, and when the valve is opened (needle lift), the needle is opened (lifted) by the magnetic attraction force of these coils. Since at least one of these coils is pre-energized, the needle (valve element) 5 is turned on by the start of fuel injection (start of valve opening).
Can be generated in advance, so that the valve can be opened with a high response when the battery voltage is normal, and even if the battery voltage decreases, the conventional The valve opening responsiveness can be maintained higher than that in the case where a plurality of coils are simultaneously energized for the first time at the start of valve opening.

That is, according to the present embodiment, the responsiveness of the fuel injection valve can be increased, and the region where the fuel injection amount can be obtained linearly with respect to the pulse width (linear region) is reduced to the low injection amount region (short pulse width). ), And the valve-opening response can be maintained high even if the battery voltage is reduced, so that the linear region is reduced in the direction of the high injection amount region (long pulse width). This can be minimized.

Further, according to the present embodiment, the influence of the battery power supply voltage drop can be suppressed without providing a high-voltage circuit for improving the responsiveness of the fuel injection valve. As a result, the product cost can be reduced. Further, since the control logic can be simplified as compared with the case where a high-voltage circuit or the like is provided, the configuration of the control circuit can be simplified, and the product cost can be reduced.

Moreover, in the present embodiment, the hold coil 3 is configured with high resistance (for example, about 10Ω) and high inductance (large number of turns), and the open coil 4 is configured with low resistance and low inductance (small number of turns). As a result, the above operation and effect can be obtained, and the following operation and effect can be obtained. In other words, (i) when pre-energizing a low-resistance, low-inductance coil in which only response improvement is considered as in the past,
Since the rise of the current is fast, there is a high possibility that the valve will be opened immediately after the start of energization unless complicated current control or the like is performed, and it is difficult to properly generate and maintain the auxiliary suction energy before the start of the valve opening. However, the hold coil 3 having high resistance and high inductance as in the present embodiment is adopted,
By pre-energizing the auxiliary suction energy, the auxiliary suction energy can be generated and maintained favorably before the start of valve opening without performing complicated current control or the like (only by energizing from the battery). Become.

(Ii) In the early stage of valve opening, a strong suction force is generated by superimposing the above-mentioned auxiliary suction energy and the suction energy by the open coil 4 having low resistance and low inductance (small number of turns). So you can
The needle (valve element) 5 can be opened (lifted) with high response. (Iii) Further, as described above, according to the hold coil 3 having high resistance and high inductance, the needle 5 can be held in the valve open state by direct drive (only energization) by a battery. Compared to a low-resistance, low-inductance coil that keeps the needle 5 open, there is no need for complicated current control to keep the needle 5 open while suppressing power consumption and heat generation. It can be. Therefore, a complicated control circuit or the like is not required, and the configuration can be simplified.

(Iv) Further, when the hold coil 3 having a high resistance and a high inductance is used, compared with a conventional coil having a low resistance and a low inductance to hold the needle 5 in an open state, a smaller current can be obtained. Since the needle 5 can be held in the valve open state, current consumption can be reduced with a simple configuration. Since the radiation noise is reduced by the reduction of the current consumption, it is possible to eliminate the need for a shielded wire or the like.

By reducing the current consumption, heat generation of the drive circuit (eg, a transistor) itself can be suppressed, and heat generation of the hold coil 3 can be suppressed, thereby improving the durability and reliability of the device. Can be improved. Next, a second embodiment of the present invention will be described. In the second embodiment, for example, when the battery voltage drops, the fuel injection valve can be more reliably opened with higher response as compared to the first embodiment.

That is, the rising characteristics of the currents of the coils 3 and 4 and the valve opening (lift) characteristics of the needle 5 depend on the battery voltage.
A change will occur in the fuel flow characteristics. Thus, in the second embodiment, a change (for example, a decrease) in the battery voltage
Accordingly, the drive signal to the transistors Tr1 and Tr2 is corrected so that the valve opening characteristic and hence the fuel flow characteristic are corrected so that a good (stable) valve opening characteristic and fuel flow characteristic can be obtained. (Rise timing and pulse width) can be corrected.

In other words, according to a change (for example, a decrease) in the battery voltage, the power supply start timing and power supply time (period) of each of the coils 3 and 4 can be variably controlled. Specifically, for example, as shown in FIG. 4, the control circuit 7 ′ in the second embodiment includes an injection timing and a control circuit 7 that also include the control circuit 7 in the first embodiment.
In addition to the injection amount (ie, fuel injection signal) determination logic 8, the battery voltage (VB) is detected, and based on this, the Pre energization (preliminary energization) characteristic of the transistor Tr 1 立 ち 上 が り the rising timing and pulse width of the drive signal of Tr 1 ( Pre energization (preliminary energization) setting logic 9 for changing setting of energization period), energization characteristic of transistor Tr2 {Tr2
Of the drive signal of the Tr2 for changing the setting of the rising timing and the pulse width (the energizing period) of the drive signal. The other system configuration is the same as that of the first embodiment shown in FIG.

In the control circuit 7 'according to the second embodiment, the pre-energization period setting change means of the present invention
It functions as a predetermined period setting change unit, and as shown in the timing chart of FIG. 5, the rising timing and ON time of the drive signal of Tr1 (timing of energizing the hold coil 3 and energizing period) are variable according to the battery voltage. In addition to the above, the rising timing and ON time of the drive signal of the Tr2 (timing of energizing the open coil 4 and energizing period) are variably controlled according to the battery voltage.

For example, when the battery voltage drops, Tpr is set so that Tpre becomes longer temporally (the ON timing of the drive signal of Tr1 is advanced) in accordance with the degree of drop.
e is changed or Topen becomes longer in time (Tr
(2) the ON timing is advanced while the OFF timing of the drive signal 2 remains unchanged, or the OFF timing is delayed with the same ON timing, or the OFF timing is delayed while the ON timing is advanced). It has become.

When the battery voltage is high, Tpre and Topen can be changed to shorter values accordingly. In this way, even when the battery voltage drops, the fuel injection valve can be more reliably opened while maintaining the maximum responsiveness, and the fuel injection valve can be opened even when the battery voltage changes. Since the responsiveness can be maintained substantially constant, the influence of the battery voltage change on the fuel injection amount can be eliminated as much as possible.

It is needless to say that the second embodiment can also provide the same functions and effects as those of the first embodiment. By the way, in each of the embodiments described above, the one provided with two coils for one valve body has been described. However, the present invention is not limited to this, and in the one provided with at least two coils, The present invention can be applied to a case where at least one coil is pre-energized.

Further, in each of the above embodiments, the configuration provided with the back electromotive absorption circuit 6 has been described. However, the present invention can be applied to a configuration without the back electromotive absorption circuit 6.

[0050]

As described above, according to the first aspect of the present invention, the valve body can be lifted by a relatively large magnetic attraction force in the early stage of the valve opening, so that the valve opening characteristics with high response. Not only can be achieved, but also the lift state of the valve body can be held with a relatively small magnetic attraction force, so that reduction of power consumption can be promoted. Of course, at least one coil is pre-energized. By the start of the valve, an auxiliary suction force for sucking the valve element can be generated in advance.

For this reason, when the battery voltage is normal, the valve can be opened with high response as in the prior art, and
Even if the battery voltage drops, for example, the valve opening responsiveness can be improved as compared with a conventional system in which a plurality of coils are simultaneously energized for the first time at the start of valve opening. That is, according to the present invention, since the responsiveness of the fuel injection valve can be increased, the region where the fuel injection amount can be obtained linearly with respect to the pulse width (linear region) is expanded toward the low injection amount region (short pulse width). And the valve opening responsiveness can be maintained high even if the battery voltage decreases, so that the linear region is prevented from being reduced in the direction of the high injection amount region (long pulse width) as much as possible. can do.

Further, even without providing a high voltage circuit or the like for improving the responsiveness of the fuel injection valve, the effect of the battery power supply voltage drop can be suppressed, so that the product cost can be reduced as compared with the case where a high voltage circuit or the like is required. can do. Further, since the control logic can be simplified as compared with the case where a high-voltage circuit or the like is provided, the configuration of the control circuit can be simplified, and the product cost can be reduced.

According to the second aspect of the present invention, since the coil to be pre-energized is formed of high resistance and high inductance, the rising speed of the current can be reduced, so that complicated current control or the like is not performed. It is possible to satisfactorily generate and maintain the auxiliary suction energy before the start of valve opening. According to the third aspect of the present invention, the rising of the current is fast, the suction force required for opening the valve can be quickly generated, and the valve opening period is shortened by a synergistic effect with the auxiliary suction force generated by the preliminary energization. Can be shortened.

According to the fourth aspect of the present invention, since the coil to be pre-energized is made of a high resistance and a high inductance, the rising speed of the current can be slowed down. It is possible to properly generate and maintain the auxiliary suction energy before the start of valve opening,
Thus, good valve opening characteristics can be achieved regardless of the battery voltage and the like.

Further, since the lift amount of the valve body can be held at a predetermined value (held in an open state) by direct drive by a battery power source, the valve body can be opened with a low-resistance and low-inductance coil as in the prior art. Compared with the case where the state is maintained, current control or the like for maintaining the valve body in the open state while suppressing problems such as heat generation can be eliminated. Therefore, a complicated control circuit or the like is not required, and the configuration can be simplified.

Furthermore, the valve element can be held in the open state with a small current compared to a conventional coil in which the valve element is held in the open state by a low-resistance and low-inductance coil. With the configuration, current consumption can be reduced. Since the radiation noise is reduced by the reduction of the current consumption, a shield line or the like can be eliminated.

Further, by reducing the current consumption, it is possible to suppress the heat generation of the drive circuit (for example, a transistor or the like) itself, and also to suppress the heat generation of the hold coil, thereby improving the durability and reliability of the device. Can be improved. Further, since the coil to be pre-energized is continuously energized to maintain the valve body in the open state, the above-described various effects can be obtained, and further, switching control of the coil to be used can be eliminated. Therefore, good holding characteristics of the valve element without a switching step can be obtained, and a circuit or the like for the switching control can be eliminated, so that the structure can be simplified and the cost can be further reduced.

According to the fifth aspect of the present invention, even when the battery power supply voltage is lowered, for example, the auxiliary suction force can be maintained at the same level as in the normal state, so that the responsiveness can be further assuredly maximized. The fuel injection valve can be opened while maintaining. Further, in combination with the invention described in claim 6, since the responsiveness of the fuel injection valve can be maintained substantially constant even when the battery power supply voltage changes, the effect of the battery voltage change on the fuel injection amount can be maintained. Can be eliminated as much as possible.

According to the sixth aspect of the invention, even when the battery power supply voltage drops, for example, the magnetic attraction force in the initial stage of opening the valve can be maintained at the same level as in the normal state, so that the battery power supply voltage changes. Even if it does, the responsiveness of the fuel injection valve can be maintained at the same level as in normal operation, so that the influence of the battery voltage change on the fuel injection amount can be eliminated as much as possible. Further, in combination with the invention described in claim 5, it is possible to further eliminate the influence of the battery voltage change on the fuel injection amount.

[Brief description of the drawings]

FIG. 1 is a block diagram according to the present invention.

FIG. 2 is a system configuration diagram according to the first embodiment of the present invention.

FIG. 3 is a timing chart illustrating drive control of a fuel injection valve in the embodiment.

FIG. 4 is a configuration diagram of a control circuit according to a second embodiment of the present invention.

FIG. 5 is a timing chart illustrating drive control of a fuel injection valve in the embodiment.

FIG. 6 is an example of a system configuration diagram of a conventional control device.

FIG. 7 is an example of a system configuration diagram of a conventional control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electromagnetic (solenoid type) fuel injection valve drive device 2 Magnetic circuit 3 Hold coil (HOLD COIL) 4 Open coil (OPEN COIL) 5 Needle (valve element) 6 Back electromotive absorption circuit 7 Control circuit 8 Injection timing and injection amount Decision logic 9 Pre-energization (pre-energization) setting logic for Tr1 10 Energization setting logic for Tr2 Tr1 transistor (for hold coil) Tr2 transistor (for open coil)

Claims (6)

[Claims] A battery power supply for supplying power to these coils for a predetermined period to generate a relatively large electromagnetic attraction based on a fuel injection start command; After the valve body is lifted, energization of at least one coil is stopped, and the lift amount of the valve body is maintained at a predetermined value with a relatively small magnetic attraction force until a fuel injection stop command is input. A drive device for an electromagnetic fuel injection valve, wherein at least one of the coils has a reserve power supply via a battery power supply within a range in which a valve body does not lift during a predetermined preliminary energization period before a fuel injection start command is input. A driving device for an electromagnetic fuel injection valve, comprising a preliminary energizing means for energizing. 2. A driving apparatus for an electromagnetic fuel injection valve according to claim 1, wherein a coil pre-energized by said pre-energizing means is set to have higher resistance and higher inductance than other coils. 3. A coil which is de-energized after the valve body is lifted by the relatively large magnetic attraction force is set to have lower resistance and lower inductance than a coil which is not de-energized until a fuel injection stop command is issued. The driving device for an electromagnetic fuel injection valve according to claim 1 or 2, wherein 4. A coil which is pre-energized by said pre-energizing means is set to have higher resistance and higher inductance than other coils and lifts a valve body by said relatively large magnetic attraction force, and then performs fuel injection. The driving device for an electromagnetic fuel injection valve according to claim 1, wherein the driving device is used as a coil that is not stopped to be energized until a stop command is issued. 5. The apparatus according to claim 1, further comprising a pre-energizing period setting changing means for changing the start of the pre-energizing period and changing the length based on a battery power supply voltage.
A drive device for an electromagnetic fuel injection valve according to claim 4. 6. The apparatus according to claim 1, further comprising a predetermined period setting changing means for changing the start or length of said predetermined period based on a battery power supply voltage. 3. The driving device for an electromagnetic fuel injection valve according to claim 1.