JP2005155799A - Solenoid valve driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply and securely detect abnormality on a driving line of an electromagnetic solenoid. <P>SOLUTION: This solenoid valve driving mechanism has a power supply supply means for supplying power supply to the electromagnetic solenoids INJ1, INJ2, the electromagnetic solenoid driving line formed by first switching elements Q1, Q2 connected mutually between the power supply supply means and one end of the electromagnetic solenoid and second switching elements Q3, Q4 connected mutually between the other end of the electromagnetic solenoid and grounding electric potential, and a control means 13 for controlling operation timing of the first and second switching elements in such a way that the first switching elements are turned on when driving the electromagnetic solenoids in accordance with operation timing of a solenoid valve and the second switching elements are turned on when predetermined time elapses from the time when the first switching elements are turned on and diagnozing failure of the electromagnetic solenoid driving line based on the timing before the predetermined time elapses after the first switching elements are turned on. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel injection control device for a vehicle, and more particularly to a solenoid valve drive device suitable for use in a fuel injection control device for a direct injection gasoline engine or diesel engine.

As this type of conventional solenoid valve drive device, a solenoid valve drive device that detects the occurrence of an abnormality in a current supply path (drive line) of an electromagnetic solenoid that drives a fuel injection valve of a diesel engine has been proposed (for example, Patent Document 1).
This solenoid valve driving device checks the voltage across the capacitor charged to a high voltage by a booster circuit to supply a peak current immediately after the start of energization of the solenoid solenoid of the fuel injection valve, thereby An abnormality is detected.

Specifically, in the conventional solenoid valve driving device described above, power is supplied to the electromagnetic solenoid immediately after the transistor as a switching element provided for controlling the power supply to the electromagnetic solenoid is turned from the ON state to the OFF state. Then, when the terminal voltage of the capacitor immediately after the fuel injection valve is driven is equal to or higher than a predetermined value, it is determined that the drive line is disconnected.

In addition, when the terminal voltage of the capacitor is equal to or lower than a predetermined value at a time immediately before the transistor is turned on from the off state, that is, immediately before the capacitor is charged with a high voltage and the fuel injection valve is driven. It is configured to determine that the drive line is short-circuited to some potential.
JP-A-9-112735

However, in the above-described conventional solenoid valve driving device, the detection timing of the voltage between the terminals of the capacitor, that is, the time immediately after the transistor is turned off from the on state, or the transistor is turned on from the off state. There is a problem that it is difficult to set the detection timing at a time point just before becoming.
In particular, when setting the timing immediately before the transistor is turned on from the off state, the charging capacity of the capacitor when the battery voltage drops decreases, and the charging time required to charge to a predetermined voltage for driving the electromagnetic solenoid Therefore, there is a problem that it is necessary to set the detection timing in consideration of this point.

Moreover, in the conventional solenoid valve driving device, the voltage across the terminals of the capacitor is twice at a time immediately after the transistor is turned off from the on state and a time immediately before the transistor is turned on from the off state. If it is not detected, there is a problem that it cannot be determined that the drive line of the electromagnetic solenoid is in a normal state.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electromagnetic valve driving device that can easily and reliably detect an abnormality in a driving line of an electromagnetic solenoid.

The invention according to claim 1 is an electromagnetic valve drive device that drives and controls the electromagnetic valve by controlling energization to the electromagnetic solenoid that drives the electromagnetic valve.
Power supply means for supplying power to the electromagnetic solenoid, a first switching element connected between the power supply means and one end of the electromagnetic solenoid, and connected between the other end of the electromagnetic solenoid and a ground potential. The first switching element is turned on when the electromagnetic solenoid is driven in accordance with the operation timing of the electromagnetic valve, and the first switching element is turned on. The operation timing of the first and second switching elements is controlled so that the second switching element is turned on when a predetermined time has elapsed from the time when the element is turned on, and the first switching element Failure diagnosis of the electromagnetic solenoid drive line is performed at the timing before the predetermined time elapses when the is turned on And having a control means.

  According to a second aspect of the present invention, in the electromagnetic valve driving device according to the first aspect of the present invention, the electromagnetic valve driving device further includes a voltage detection circuit that detects a voltage of the electromagnetic solenoid driving line, and the control means includes the voltage within the predetermined time. An abnormality determination of the drive line connected to the electromagnetic solenoid is performed based on a detection output of a detection circuit, and control is performed to stop energization of the electromagnetic solenoid when an abnormality occurs. .

  According to a third aspect of the present invention, in the electromagnetic valve driving device according to the second aspect, when the energization to the electromagnetic solenoid is stopped by the abnormality determination by the control means, the voltage of the electromagnetic solenoid driving line is set. A first voltage detection circuit for detecting, and a second voltage detection circuit for detecting the voltage of the drive line within the predetermined time, and the control means outputs a detection output of the second voltage detection circuit. Based on this, the abnormality of the drive line connected to the electromagnetic solenoid is determined, and when an abnormality occurs, control is performed to stop energization of the electromagnetic solenoid, and the detection of the first voltage detection circuit is performed. A failure type of a power line connected to the electromagnetic solenoid is determined based on an output.

  As described above, according to the present invention, the first switching element connected to the power supply voltage supply means (including the battery) side of the electromagnetic solenoid performs voltage detection for abnormality determination in the drive line of the electromagnetic solenoid. Since it is set to be performed within a predetermined time from the time when it is turned on, it is easy to set the detection timing, and therefore, the abnormality determination of the drive line can be performed easily and easily.

In addition, according to the present invention, it is possible to determine the abnormality of the drive line connected to the electromagnetic solenoid within the predetermined time. Therefore, when an abnormality occurs, the energization to the electromagnetic solenoid is immediately stopped. can do.
Furthermore, after the energization to the electromagnetic solenoid is stopped when an abnormality occurs in the drive line, it is possible to determine the failure type, that is, whether the drive line of the electromagnetic solenoid is disconnected or in a ground fault state.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the configuration of an electromagnetic valve driving device according to an embodiment of the present invention. In the embodiment of the present invention, an electromagnetic valve driving device applied to a fuel injection control device of a direct injection gasoline engine will be described as an example. In FIG. 1, a battery EB is externally attached to a terminal 50 of the electromagnetic valve driving device 1.

The electromagnetic valve driving device 1 includes a boost control circuit 10, an input interface circuit 11, an output interface circuit 12, a microcomputer 13, hold current circuits 14 and 15, voltage detection circuits A16 and 17, a voltage detection circuit B18, 19 and electromagnetic solenoids INJ1 and INJ2 for driving fuel injection valves (electromagnetic valves) for supplying fuel to each cylinder of the engine (not shown). It should be noted that the number of electromagnetic solenoids that drive the fuel injection valve is actually provided for the number of cylinders of the engine, but only two are shown in FIG. 1 for convenience of explanation.
The positive electrode of the battery EB is connected to one end of the inductance L1 and the emitters of the PNP transistors Q5 and Q6 via the terminal 50, and the negative electrode is grounded.

The other end of the inductance L1 is connected to the drain of the NMOS transistor MN1, the source of the NMOS transistor MN1 is grounded, and the gate is connected to the output terminal of the boost control circuit 10.
The drain of the NMOS transistor MN1 is connected to the anode of the diode D1, and the cathode of the diode D1 is grounded via the capacitor C1 and is connected to the emitters of the PNP transistors Q1 and Q2. The bases of the PNP transistors Q1 and Q2 are connected to the output terminal of the output interface circuit 12 via resistors R1 and R2, respectively.

The collectors of the PNP transistors Q1 and Q2 are connected to the collectors of the NPN transistors Q3 and Q4 via the electromagnetic solenoids INJ1 and INJ2, respectively, and to the cathodes of the diodes D4 and D5. The anodes of the diodes D4 and D5 are each grounded.
The bases of the NPN transistors Q3 and Q4 are connected to the output terminal of the output interface circuit 12 via resistors R3 and R4, respectively.
The emitters of NPN transistors Q3 and Q4 are connected in common and grounded through a resistor R5.

On the other hand, the bases of the PNP transistors Q5 and Q6 are connected to the output terminals of the hold current circuits 14 and 15, respectively, and the collectors are connected to the anodes of the diodes D2 and D3. The cathodes of the diodes D2 and D3 are connected to the cathodes of the diodes D4 and D5, respectively.
The input terminals of the current detection circuits A16 and A17 are connected to the collectors of the PNP transistors Q5 and Q6, respectively. The input terminals of the current detection circuits B18 and B19 are connected to the collectors of the NPN transistors Q3 and Q4, respectively.
The detection outputs of the current detection circuits A16 and 17 and the current detection circuits B18 and B19 are input to the microcomputer 13 as digital signals.

The step-up control circuit 10 has a function of performing switching control of the NMOS transistor MN1 based on a control signal output from the microcomputer 13. The boost control circuit 10, NMOS transistor MN1, inductance L1, diode D1, and capacitor C1 constitute a DC-DC converter. This DC-DC converter and battery EB correspond to the power supply means of the present invention.
The battery EB is 12-14V. The DC-DC converter has a function of boosting the output voltage of the battery EB and supplying a current necessary for driving the electromagnetic solenoids INJ1 and INJ2.

  The PNP transistors Q1 and Q2 each correspond to a first switching element of the present invention, and the NPN transistors Q3 and Q4 each correspond to a second switching element of the present invention. The current path from the electromagnetic solenoids INJ1, INJ2 to the battery voltage EB or the ground potential corresponds to the drive line of the electromagnetic solenoid of the present invention.

The input interface circuit 11 includes engine speed Ne, engine cooling water temperature TW, throttle opening TH, atmospheric pressure Pa, and intake pipe negative pressure Pb, which are parameters for calculating the fuel injection amount, by various sensors not shown. The output is detected and input to the microcomputer 13.
The hold current circuits 14 and 15 generate a current necessary for maintaining the fuel injection valve in the open state immediately after driving the electromagnetic solenoids INJ1 and INJ2 based on the control signal output from the output interface circuit 12 from the microcomputer 13. It has a function of supplying to the electromagnetic solenoids INJ1 and INJ2.

The voltage detection circuits A16 and A17 each have a function of detecting the voltage on the side of the electromagnetic solenoid drive line to which one end of the electromagnetic solenoids INJ1 and INJ2 is connected, specifically the voltage on the collector side of the PNP transistors Q5 and Q6. ing. The voltage detection circuits A16 and 17 correspond to the first voltage detection circuit of the present invention.
The voltage detection circuits B18, 19 detect the voltage on the side of the electromagnetic solenoid drive line to which the other ends of the electromagnetic solenoids INJ1, INJ2 are connected, specifically, the voltage on the collector side of the NPN transistors Q3, Q4, respectively. It has a function. The voltage detection circuits B18 and 19 correspond to the second voltage detection circuit of the present invention.

The microcomputer 13 takes in the detection outputs of various sensors that indicate the operating state of the engine via the input interface circuit 11, and executes a built-in control program based on these detection outputs, whereby the fuel injection amount in each cylinder of the engine. And has a function of controlling each part.
Further, the microcomputer 13 operates the first and second switching elements according to the operation timing of the fuel injection valve (solenoid valve), energizes the electromagnetic solenoids INJ1, INJ2, and drives the electromagnetic solenoids INJ1, INJ2. In the energization period, the electromagnetic solenoids INJ1 and INJ2 have a function of diagnosing a drive line failure. The microcomputer 13 corresponds to the control means of the present invention.

  Next, the configuration of the voltage detection circuit A16 is shown in FIG. The configuration of the voltage detection circuit A17 is the same. In FIG. 2, the voltage detection circuit A16 includes an NPN transistor Q10 and resistors R10, R11, R12, and R13. The emitter of the NPN transistor Q10 is grounded, and the collector is connected to a 5V power supply line (supplied from a 5V constant voltage circuit not shown) via a resistor R10.

A series circuit of resistors R11, R12, and R13 is connected between the 14V power supply line supplied from the battery EB and the ground, and the base of the NPN transistor Q10 is connected to the connection point between the resistors R12 and R13. Has been. The connection point between the resistors R11 and R12 is connected to the anode of the diode D2 in FIG.
The detection output of the voltage detection circuit A16 is output from the collector of the NPN transistor Q10 to the microcomputer 13.

  Next, the configuration of the voltage detection circuit B18 is shown in FIG. The configuration of the voltage detection circuit B19 is the same. In FIG. 2, the voltage detection circuit B18 includes an NPN transistor Q20 and resistors R20, R21, and R22. The emitter of the NPN transistor Q20 is grounded, and the collector is connected to a 5V power supply line (supplied from a 5V constant voltage circuit not shown) via a resistor R20.

One end of the resistor R22 of the series circuit composed of the resistors R21 and R22 is grounded, and one end of the resistor R21 is connected to the collector of the transistor Q3 in FIG.
The base of the NPN transistor Q20 is connected to the connection point between the resistor R21 and the resistor R22. Further, the detection output of the voltage detection circuit B18 is output from the collector of the NPN transistor Q20 to the microcomputer 13.

  The operation of the electromagnetic valve driving device according to the embodiment of the present invention having the above-described configuration will be described with reference to the flowchart of FIG. 4 and the timing chart shown in FIG. In the above configuration, when fuel injection control is started (step 100), the microcomputer 13 takes in the detection outputs of various sensors indicating the operating state of the engine via the input interface circuit 11, and based on a built-in control program. A fuel injection amount in each cylinder of the engine is calculated, and a fuel injection time Ti (FIG. 5A) that is a valve opening time of the solenoid valve of the fuel injection device corresponding to the fuel injection amount is calculated.

  On the other hand, in response to the control signal from the microcomputer 13, the boost control circuit 10 controls the switching of the NMOS transistor MN1, boosts the battery voltage EB, and the terminal voltage of the capacitor C1 is the current required for the initial driving of the electromagnetic solenoids INJ1 and INJ2. The battery is charged until the voltage is high enough to supply (for example, 150V). Here, since the drive control of the electromagnetic solenoids INJ1 and INJ2 is performed in the same manner, the control of the electromagnetic solenoid INJ1 and the failure diagnosis of the drive line will be described below.

Next, the microcomputer 13 sends a drive timing signal (FIG. 5B) that goes high at time t0, which is the start time of the fuel injection time Ti, to the base of the PNP transistor Q1 via the output interface circuit 12 and the resistor R1. Output.
As a result, the PNP transistor Q1 is turned on, but at this time, the NPN transistor Q3 is in the off state. Next, the microcomputer 13 outputs a drive timing signal (FIG. 3D) that becomes high level at time t1 after time Δt1 from time t0 to the base of the NPN transistor Q3, and the transistor Q3 is turned on.

As a result, the current necessary for opening the fuel injection valve (electromagnetic valve) is supplied to the electromagnetic solenoid INJ1 by the high voltage charged in the capacitor C1 (FIG. 5E).
Further, at time t2, the drive timing signal output from the microcomputer 13 to the bases of the PNP transistor Q1 and the NPN transistor Q3 falls, so that the current supplied from the capacitor C1 to the electromagnetic solenoid INJ1 is cut off. The drive timing signal supplied to the base of the NPN transistor Q3 rises at time t3 after time t2 from time t2.

At the same time, the hold current circuit 14 is activated under the control of the microcomputer 13. The drive timing signal supplied to the base of the NPN transistor Q3 falls at time t4 when the fuel injection time Ti ends.
The hold current circuit 14 outputs a duty control signal for switching the PNP transistor Q5 in order to supply the electromagnetic solenoid INJ1 with a current for maintaining the open state of the fuel injection valve driven by the solenoid valve solenoid INJ1. Output to the base of.

This duty control signal is output until time t4 when the fuel injection time Ti ends (FIG. 5C), and the current for maintaining the open state of the fuel injection valve in the electromagnetic solenoid INJ1 during the period of time t2 to t4. Is supplied (FIG. 5E).
On the other hand, the transistor Q3 is turned on at time t1, but the failure diagnosis of the drive line of the electromagnetic solenoid INJ1 by the microcomputer 13 is a time zone of Δt1 from time t0 to t1 (corresponding to a predetermined time in the present invention) and. It is performed in a time zone after time t2.

That is, the microcomputer 13 generates a high voltage (for example, a voltage of 75 V or more) on the drive line side (collector of the transistor Q3) of the electromagnetic solenoid INJ1 based on the detection output of the voltage detection circuit B18 during the time period Δt1 from time t0 to time t1. ) Is determined (step 101).

  If no abnormality such as disconnection or ground fault occurs in the drive line of the electromagnetic solenoid INJ1, the potential on the drive line side of the electromagnetic solenoid INJ1 is almost the same as the terminal voltage of the capacitor C1, so that a high voltage (FIG. 5 (F )) Is input to the voltage detection circuit B18. In the voltage detection circuit B18, since the voltage divided by the resistors R21 and R22 is applied between the base and emitter of the NPN transistor Q20, the transistor Q20 is turned on, and the microcomputer 13 outputs a low level detection output. The microcomputer 13 determines that the drive line of the electromagnetic solenoid INJ1 is normal (Steps 101 and 102).

  On the other hand, when an abnormality such as disconnection or ground fault occurs in the drive line of the electromagnetic solenoid INJ1, the drive line side potential of the electromagnetic solenoid INJ1, that is, the collector potential of the NPN transistor Q3 is a ground potential or a low voltage. It becomes a state. Accordingly, since a ground potential or a low voltage is applied between the base and emitter of the NPN transistor Q20 in the voltage detection circuit B18, the NPN transistor Q20 is turned off, and a high level detection output is input to the microcomputer 13. The microcomputer 13 determines that the drive line of the electromagnetic solenoid INJ1 is abnormal, and performs an abnormality process that includes turning off the transistors Q1, Q3, and Q5 so as to cut off the energization of the electromagnetic solenoid INJ1. (Steps 101 and 103).

Next, the microcomputer 13 determines from the output voltage from the voltage detection circuit A16 whether the failure type, that is, whether the abnormality of the drive line of the electromagnetic solenoid INJ1 is a disconnection or a ground fault.
As for the circuit configuration of the voltage detection circuit A16, as shown in FIG. 2, the anode of the diode D2 is connected to the connection point of the resistors R11 and R12, and the cathode of the diode D2 is connected to the electromagnetic solenoid drive line. Therefore, when the electromagnetic solenoid drive line is disconnected, the voltage 14V of the battery EB divided by the resistors R11, R12 and R13 is applied between the base and emitter of the NPN transistor Q10, so that the NPN transistor Q10 is in the on state. Thus, the low level detection output is input to the microcomputer 13, and the microcomputer 13 determines that the drive line of the electromagnetic solenoid INJ1 is disconnected (steps 104 and 105).

When the electromagnetic solenoid drive line is grounded, the anode side of the diode D2 is also at the ground potential, and the divided voltages of the resistors R11, R12, and R13 are at the ground potential. The ground potential is applied, the NPN transistor Q10 is turned off, a high level detection output is input to the microcomputer 13, and the microcomputer 13 determines that the drive line of the electromagnetic solenoid INJ1 is grounded (steps 104 and 106). .
The above operation is the same for the electromagnetic solenoid INJ2.

  According to the solenoid valve drive device of this embodiment, the voltage detection for determining abnormality in the drive line of the electromagnetic solenoid is connected to the power supply voltage supply means (including the battery) side of the electromagnetic solenoid INJ1 (INJ2). Since the switching element Q1 (Q2) is set to be performed within a predetermined time (Δt1) from the time when the switching element Q1 (Q2) is turned on, it is easy to set the detection timing. And can be done easily.

In addition, according to the present invention, it is possible to determine the abnormality of the drive line connected to the electromagnetic solenoid within the predetermined time. Therefore, when an abnormality occurs, the energization to the electromagnetic solenoid is immediately stopped. can do.
Further, after the energization to the electromagnetic solenoid is stopped when an abnormality occurs in the drive line, the failure type of the electromagnetic solenoid, i.e., whether the drive line of the electromagnetic solenoid is disconnected or is in a ground fault state. Can be judged.

The figure which shows the structure of the solenoid valve drive device which concerns on embodiment of this invention. The circuit diagram which shows the structure of the voltage detection circuit A in the solenoid valve drive device shown in FIG. The circuit diagram which shows the structure of the voltage detection circuit B in the solenoid valve drive device shown in FIG. The flowchart which shows the content of the failure diagnosis process in the drive line of the electromagnetic solenoid by the solenoid valve drive device shown in FIG. The timing chart for demonstrating operation | movement of the solenoid valve drive device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Solenoid valve drive device 10 ... Boost control circuit 11 ... Input interface circuit 12 ... Output interface circuit 13 ... Microcomputer 14, 15 ... Hold current circuit 16, 17 ... Current detection circuit A
18, 19 ... current detection circuit B
INJ1, INJ2 ... Electromagnetic solenoid

Claims (3)

In an electromagnetic valve driving device that controls driving of the electromagnetic valve by controlling energization to an electromagnetic solenoid that drives the electromagnetic valve,
Power supply means for supplying power to the electromagnetic solenoid;
A first switching element connected between the power supply means and one end of the electromagnetic solenoid;
An electromagnetic solenoid drive line formed by a second switching element connected between the other end of the electromagnetic solenoid and a ground potential;
When the electromagnetic solenoid is driven in accordance with the operation timing of the electromagnetic valve, the first switching element is turned on, and when a predetermined time elapses from when the first switching element is turned on. Controlling the operation timing of the first and second switching elements so that the two switching elements are turned on;
Control means for performing failure diagnosis of the electromagnetic solenoid drive line at a timing before the first switching element is turned on and the predetermined time has elapsed;
An electromagnetic valve driving device comprising: A voltage detection circuit for detecting a voltage of the electromagnetic solenoid drive line;
The control means performs an abnormality determination of the drive line connected to the electromagnetic solenoid based on a detection output of the voltage detection circuit within the predetermined time, and if an abnormality occurs, energization of the electromagnetic solenoid is performed. The electromagnetic valve driving device according to claim 1, wherein the electromagnetic valve driving device is controlled to stop. A first voltage detection circuit for detecting a voltage of the electromagnetic solenoid drive line at a time when energization to the electromagnetic solenoid is stopped by an abnormality determination by the control means;
A second voltage detection circuit for detecting a voltage of the drive line within the predetermined time,
The control means determines an abnormality of the drive line connected to the electromagnetic solenoid based on a detection output of the second voltage detection circuit, and stops the energization to the electromagnetic solenoid when an abnormality occurs. 3. The solenoid valve driving device according to claim 2, wherein a failure type of a power supply line connected to the electromagnetic solenoid is determined based on a detection output of the first voltage detection circuit. .

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