JP4465933B2 - Electromagnetic actuator drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic actuator driving device, and can be used for driving, for example, an injector (fuel injection valve).
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, an electromagnetic actuator driving device that performs initial driving on an injector is known as an electromagnetic actuator using discharge of high-voltage charging energy stored in an energy storage capacitor. When the injector is initially driven, capacitor charge / discharge control is generally performed in which all charges stored in the energy storage capacitor are discharged and then charged again.
[0003]
The above-described injector drive status (normal / abnormal) can be known from the state of an IJf signal (fail signal) from an injector driver (Electric Driver Unit; hereinafter simply referred to as “EDU”) that controls the injector. . That is, this IJf signal is reversed when the current flowing through the solenoid coil of the injector exceeds the threshold current for abnormality determination in the middle of its rise, and it can be seen that the injector is normally driven.
[0004]
Here, if the internal impedance of the injector is originally large, even if some abnormality occurs in the solenoid coil of the injector, for example, leakage occurs and the internal impedance becomes somewhat small, the current flowing through the solenoid coil of the injector is the threshold current. There is no flow beyond. In other words, in this case, since the IJf signal does not invert when an abnormality occurs, the drive status (normal / abnormal) of the injector can be accurately known according to the IJf signal at a predetermined timing. .
[0005]
[Problems to be solved by the invention]
In recent years, in order to improve exhaust gas purification of an internal combustion engine, it has been required to divide the fuel injection amount from the injector into a plurality of times and to supply the fuel by shortening the injection interval. In order to cope with this, an injector having a small internal impedance tends to be employed. In other words, by using an injector with a small internal impedance, it is possible to reduce the energy required for the initial drive of the injector, and it is possible to cope with continuous injection with a short injection interval coupled with the use of a large capacity energy storage capacitor. is there.
[0006]
However, in the above-mentioned, since the internal impedance of the injector becomes small, there is no difference in the current flowing through the injector between normal time and abnormal time, and normal / abnormal determination based on the threshold current is difficult. In addition, since the energy storage capacitor discharges all accumulated charges at once, there is a problem that it takes a long time to charge after discharge, and the discharge interval is limited, making it difficult to perform a plurality of continuous discharges.
[0007]
Accordingly, the present invention has been made to solve such a problem, and enables continuous operation with a short operation interval of the electromagnetic actuator, and according to the situation where the current value flowing through the electromagnetic actuator reaches a predetermined current value. Therefore, an object of the present invention is to provide an electromagnetic actuator driving apparatus capable of accurately outputting a signal indicating whether the electromagnetic actuator is normal or abnormal.
[0008]
[Means for Solving the Problems]
According to the electromagnetic actuator driving apparatus of the present invention, the current detection unit detects the current value flowing through the electromagnetic actuator due to the discharge of the energy storage capacitor accumulated by driving the step-up switching circuit by the control circuit. A comparison / determination unit compares and determines a predetermined current value for initially driving the electromagnetic actuator. When it is determined by the comparison determination means that the current value has reached a predetermined current value, the discharge stopping means stops the discharge from the energy storage capacitor to the electromagnetic actuator, and the signal output means normalizes the electromagnetic actuator. A signal is output. As a result, the next charging time can be shortened, and as a result, a continuous operation with a short operation interval with respect to the electromagnetic actuator is possible. On the other hand, when the comparison / determination means determines that the current value does not reach the predetermined current value, the signal output means outputs a signal indicating that the electromagnetic actuator is abnormal. Thus, normal / abnormal determination can be made accurately without being affected by the internal impedance of the electromagnetic actuator.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
[0010]
FIG. 1 is a circuit diagram showing an electrical configuration of an EDU (injector driving device) to which an electromagnetic actuator driving device according to an embodiment of the present invention is applied.
[0011]
In FIG. 1, an EDU 100 is connected to an injector (electromagnetic actuator) 110 (in the drawing, a single configuration is shown for the sake of convenience) for injecting fuel into a plurality of cylinders constituting an internal combustion engine (not shown). The battery power supply + B, which is a DC power supply from the battery BAT, is input, and an IJt signal, which is a drive signal for fuel injection by the injector 110, is input from a well-known ECU (Electronic Control Unit) (not shown). ing. The EDU 100 outputs an IJf signal, which is a fail signal indicating the drive status (normal / abnormal) of the injector 110, to the ECU. In the present embodiment, as will be described later, if the IJf signal at a predetermined timing is in a “Hi (high)” state, the drive state of the injector 110 is normal and an appropriate fuel injection amount is set to an internal combustion engine (illustrated). It can be determined by the ECU that the injection is supplied to the abbreviation).
[0012]
In the EDU 100, the battery power source + B is connected to one end of a coil L1, and the other end of the coil L1 is connected to the ground via a switching element SW1 composed of a transistor (MOSFET) forming a step-up switching circuit. The gate side of the switching element SW1 is connected to a control circuit 10 which will be described later. The other end of the coil L1 is connected to an energy storage capacitor C1 through a backflow prevention diode D1.
[0013]
Charging energy of the energy storage capacitor C1 is applied to one end of the solenoid coil 111 of the injector 110 via a switching element SW2 made of a transistor (MOSFET). The gate side of the switching element SW2 is connected to a control circuit 10 which will be described later.
[0014]
Further, a switching element SW3 composed of a transistor (MOSFET) and a backflow prevention diode D2 are connected in parallel with the coil L1, the backflow prevention diode D1 and the switching element SW2. The gate side of the switching element SW3 is connected to a control circuit 10 which will be described later. The diode D3 is a current return diode. The other end of the solenoid coil 111 of the injector 110 is connected to the ground via a switching element SW4 composed of a transistor (MOSFET) and a resistor R1. The gate side of the switching element SW4 is connected to a control circuit 10 which will be described later.
[0015]
The control circuit 10 of the EDU 100 mainly includes a charging circuit including a DC-DC converter (not shown), a constant voltage circuit, and the like. The control circuit 10 receives the battery power supply + B and IJt signals input to the EDU 100, and outputs a driving signal 10 to output a switching element. SW1, SW2, SW3 and SW4 are ON / OFF controlled.
[0016]
The switching element SW4 and the resistor R1 are connected to the control circuit 10 and connected to the non-inverting (+) input terminal side of the comparator 21. On the other hand, the comparison voltage Vref obtained by dividing the predetermined voltage from the control circuit 10 by the resistors R2 and R3 is input to the inverting (-) input terminal side of the comparator 21. This comparison voltage Vref is set in advance so as to correspond to a suitable current value assumed to flow when the solenoid coil 111 of the injector 110 is normal.
[0017]
The output terminal side of the comparator 21 is connected between the control circuit 10 and the resistor R2 via the resistor R4, is connected to the base side of the switching element SW5 made of a transistor, and S ( Set) Connected to the terminal side. The collector side of the switching element SW5 is connected to a signal line from a control circuit 10 that drives the gate side of the switching element SW2 to control ON / OFF of the switching element SW2. The comparator 21 has a hysteresis characteristic by a feedback action by a resistor R5 connected in parallel between the output terminal side of the comparator 21 and the inverting (-) input terminal side.
[0018]
Further, the R (reset) terminal side of the flip-flop circuit 22 is connected to the control circuit 10. The Q (output) terminal side of the flip-flop circuit 22 is connected to the IJf terminal via the drive circuit 23.
[0019]
Next, the operation will be described with reference to FIGS. Here, FIG. 2 is a time chart showing transition states of various signals in FIG.
[0020]
1 and 2, an ignition switch (not shown) is in an “ON” state, and the battery power source + B is supplied from the battery BAT to the EDU 100. Then, the ON / OFF control of the switching element SW1 by the output voltage from the DC-DC converter (not shown) is repeated by the control circuit 10 in the EDU 100, and the self-inductive energy generated in the coil L1 is energized via the diode D1. Charging of the storage capacitor C1 is started (time t1 in FIG. 2). Then, by the ON / OFF control of the switching element SW1 by the control circuit 10, the voltage VC1 [V] across the energy storage capacitor C1 is boosted until reaching a predetermined high voltage (time t2 in FIG. 2). .
[0021]
Next, when the IJt signal from the ECU rises from “Lo (low)” to “Hi”, the control circuit 10 turns on the switching elements SW2, SW3, SW4 (time t2 in FIG. 2). . Then, first, a current based on charging energy from the energy storage capacitor C1 flows through the switching element SW2 through the solenoid coil 111 of the injector 110 and further through the switching element SW4 through the resistor R1. The current IR1 flowing through the resistor R1 is gradually increased from time t2 as shown in FIG.
[0022]
When the voltage on the non-inverting (+) input terminal side of the comparator 21 based on the current IR1 flowing through the resistor R1 becomes equal to the comparison voltage Vref input to the inverting (−) input terminal side of the comparator 21, The switching element SW5 is changed from "OFF" to "ON" by the output voltage from the output terminal side (time t3 in FIG. 2). At this time, the injector 110 is driven to open by a large current flowing through the solenoid coil 111, and a well-known fuel injection is started. At this time, the current IR1 flowing through the resistor R1 becomes a peak current value Ip as a predetermined current value for initially driving the injector 110.
[0023]
Then, the switching element SW2 is turned “OFF” and the discharge from the energy storage capacitor C1 is stopped. At the same time, the switching circuit SW3 is once turned “OFF” by the control circuit 10 (time t3 in FIG. 2). As a result, when the current IR1 flowing through the resistor R1 decreases and falls to a predetermined current (time t4 in FIG. 2), ON / OFF control by the switching element SW3 is started by the control circuit 10, and the battery coil + B is supplied to the solenoid coil 111 of the injector 110. A predetermined current based on is supplied, and the open state of the injector 110 is maintained. At this time, the switching element SW5 is returned from "ON" to "OFF".
[0024]
At the same time, the ON / OFF control by the switching element SW1 is resumed by the control circuit 10, and charging is started again until the voltage VC1 across the energy storage capacitor C1 reaches a predetermined voltage (time t4 in FIG. 2). When the fuel injection time commensurate with the current fuel injection amount from the injector 110 ends (time t5 in FIG. 2), the IJt signal from the ECU side falls from “Hi” to “Lo”. Then, the control circuit 10 sets the switching element SW3 to “OFF” and the switching element SW4 to “OFF” (time t5 in FIG. 2), and a predetermined current flowing through the solenoid coil 111 of the injector 110 (corresponding to a current flowing through the resistor R1). Is stopped. Note that the voltage VC1 across the energy storage capacitor C1 is boosted from the reduced voltage to a predetermined voltage by time t5 at the latest.
[0025]
Here, when the current IR1 flowing through the solenoid coil 111 of the injector 110 reaches the peak current Ip which is a preset current as described above, an appropriate fuel injection amount from the injector 110 is an internal combustion engine (not shown). The output voltage from the output terminal side of the comparator 21 is input to the S terminal of the flip-flop circuit 22. Therefore, “Hi” of the IJf signal is output from the Q terminal side of the flip-flop circuit 22 to the IJf terminal via the drive circuit 23 for current amplification (time t3 to time t5 in FIG. 2).
[0026]
The output state from the Q terminal side of the flip-flop circuit 22 is that the switching element SW3 is turned “OFF” simultaneously with the fall of the IJt signal from “Hi” to “Lo” and flows to the solenoid coil 111 of the injector 110. When the current IR1 becomes "0 (zero)" (time t5 in FIG. 2), it is reset by the signal output from the control circuit 10 to the R terminal side of the flip-flop circuit 22 and inverted to "Lo". Therefore, after a predetermined time when the IJt signal to the EDU 100 is changed from “Lo” to “Hi”, the ECU 110 injects and supplies an appropriate fuel injection amount from the injector 110 if the IJf signal from the EDU 100 is in the “Hi” state. Can be determined.
[0027]
Thus, an EDU (injector driving device) 100 as an electromagnetic actuator driving device of the present embodiment includes a battery power source + B as a DC power source, a coil L1 having one end connected to the battery power source + B, and a coil L1. A booster switching circuit composed of a switching element SW1 connected to the end, the control circuit 10 and the like, and this booster switching circuit are connected in parallel via a backflow prevention diode D1 and supplied to an injector 110 as an electromagnetic actuator. An energy storage capacitor C1 for storing the energy to be stored, current detection means for detecting a current value flowing through the injector 110 due to discharge of the energy storage capacitor C1 as a current IR1 flowing through the resistor R1, and a current detected by the current detection means Place for initial driving of IR1 and injector 110 Comparison determining means comprising a control circuit 10, a comparator 21, a resistor R5, etc. for comparing and determining a peak current value Ip corresponding to a comparison voltage Vref obtained by dividing a predetermined voltage by resistors R2 and R3 as current values, and comparison determining means When it is determined that the current IR1 has reached the peak current value Ip, the discharge stop means including the switching elements SW2 and SW5 for stopping the discharge from the energy storage capacitor C1 to the injector 110, and the injector 110 When the discharge to the stop is stopped, the IJf signal for normalizing the injector 110 is output, and when the current determining unit IR determines that the current IR1 does not reach the peak current value Ip, the IJf signal for abnormally injecting the injector 110 Control circuit 10, flip-flop circuit 22, drive circuit 23, etc. And a signal output means.
[0028]
That is, the energy from the energy storage capacitor C1 stored by driving the step-up switching circuit by the control circuit 10 is supplied to the injector 110 when the switching element SW2 is “ON”. When the current IR1 flowing through the resistor R1 corresponding to the current value flowing through the injector 110 reaches the peak current value Ip (corresponding to Vref), the switching element SW5 is turned from “OFF” to “ON” by the output from the comparator 21. The discharge from the energy storage capacitor C1 to the injector 110 is stopped by switching the switching element SW2 from "ON" to "OFF". At this time, the IJf signal is inverted by the output from the comparator 21 via the flip-flop circuit 22 and the drive circuit 23, so that the injector 110 is normal, and electric charge remains in the energy storage capacitor C1. The next charging time is short, and as a result, the fuel injection amount from the injector 110 can be supplied by being divided into a plurality of times by shortening the injection interval. On the other hand, when the current IR1 flowing through the injector 110 does not reach the peak current value Ip, it is understood that the injector 110 is abnormal because there is no output from the comparator 21 and the IJf signal is not inverted. As a result, it is possible to accurately determine normality / abnormality without being influenced by the internal impedance of the injector 110.
[0029]
By the way, in the said Example, although charging / discharging control of the capacitor | condenser for energy storage with respect to one injector was demonstrated, when implementing this invention, it is not limited to this, When an internal combustion engine is a multicylinder In addition, the charge / discharge control can be similarly performed on the energy storage capacitor for the injector of each cylinder. In this case, since it is necessary to cope with the input of each IJt signal to the injector of each cylinder, a considerable number of elements increase with respect to the increased number of cylinders in the conventional charge / discharge control circuit. According to the present invention, in order to control the increased solenoid coil of the injector, only the elements corresponding to the switching element SW4 and the resistor R1 shown in FIG. 1 need be added, and the increase can be suppressed to a minimum.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an electrical configuration of an EDU to which an electromagnetic actuator driving apparatus according to an example of an embodiment of the present invention is applied.
FIG. 2 is a time chart showing transition states of various signals in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Control circuit 21 Comparator 22 Flip-flop circuit 100 EDU (Injector drive device)
R1, R2, R3 resistors SW1 to SW5 switching elements

Claims (1)

DC power supply,
A coil having one end connected to the DC power source;
A step-up switching circuit connected to the other end of the coil;
An energy storage capacitor that is connected in parallel to the step-up switching circuit via a backflow prevention diode and stores energy supplied to the electromagnetic actuator;
Current detection means for detecting a current value flowing through the electromagnetic actuator due to discharge of the energy storage capacitor;
Comparison determination means for comparing and determining the current value detected by the current detection means and a predetermined current value for initially driving the electromagnetic actuator;
Discharge stopping means for stopping discharge from the energy storage capacitor to the electromagnetic actuator when the current value reaches the predetermined current value in the comparison determination means;
When the current value reaches the predetermined current value by the comparison determination unit and the discharge to the electromagnetic actuator is stopped by the discharge stop unit, a signal for normalizing the electromagnetic actuator is output, and An electromagnetic actuator driving device comprising: a signal output means for outputting a signal indicating abnormality of the electromagnetic actuator when the current value does not reach the predetermined current value by the comparison and determination means.

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