JP3508407B2 - Drive device for fuel injection valve for internal combustion engine - Google Patents

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 a fuel injection valve (so-called injector) for injecting fuel in an internal combustion engine, and more particularly to a drive device applicable to a fuel injection valve used in a cylinder injection system.

[0002]

2. Description of the Related Art As a conventional injector driving device for injecting fuel from an internal combustion engine, for example, as described in Japanese Patent Laid-Open No. 4-63941, a driving power supply circuit is provided along with an increase in the rotational speed of the internal combustion engine. It is known to increase the magnitude of the driving voltage.

Further, for example, as disclosed in Japanese Patent Application Laid-Open No. 3-275957, at the time of valve opening, a current larger than the valve holding current of the solenoid valve exciting coil is passed to shorten the delay time of valve opening and / or valve closing. It has been known.

[0004]

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 4-63941 and Japanese Unexamined Patent Application Publication No. 3-275957 disclose that the rise time of the injector drive current is further increased and the peak value of the drive current is increased. In addition, there is a problem that the holding current cannot be controlled to the optimum value.

For example, a fuel injection valve for injecting fuel in a cylinder requires a larger valve opening / closing force.

The object of the present invention is to make the rise time of the drive current of the injector faster, to control the peak current and the holding current to constant values, and to open and close the cylinder injection valve even if it is applied. The present invention provides a drive device (injector drive device) for a fuel injection valve that can drive a fuel injection device at high speed.

[0007]

In order to achieve the above object, in the present invention, means for forming an energizing circuit of a coil of a fuel injection valve (for example, a semiconductor switching element) and a magnitude of a current flowing through the circuit are set. A means for adjusting (for example, another semiconductor switching element) is provided.

Specifically, an injector, a drive circuit for driving the injector, and a drive circuit for switching the current between normal and reverse in order to speed up the rise and fall of the current.
BW circuit and PW that controls the injector drive circuit
The M current control circuit, a current command switching generation circuit that generates a current command value by switching the PWM current control circuit, and a booster circuit means for supplying a current to the injector via the H-blitch circuit, and an input command for injector control Injector valve opening / in response to the injector pulse command
The valve closing time is controlled to control the fuel injection time of the internal combustion engine at high speed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a control system configuration diagram of an injector drive device for an internal combustion engine according to an embodiment of the present invention.

The 12V system voltage V _B of the battery B is input to the booster circuit 1, and a boosted voltage V _DC of a high voltage is output and supplied to the drive circuit 2.

Reference numeral 5 is a current command switching generation circuit, which is a current command I _INC and pulse commands P ₁ , P ₃ , P ₃ ′ (inversion signal) based on an injector pulse command P ₁ generated from an automobile engine control system. To occur. In the PWM current control circuit 4, the deviation between the current command I _INC given by the current command switching generation circuit and the feedback signal detected by the current detection resistor R _{SH as the} voltage signal V _INJ of the current flowing through the drive circuit 2 is calculated. A PWM signal for controlling the current is generated.

In the drive circuit 2, the injector current I _INJ flowing through the injector coil 40 is controlled based on the PWM signal generated by the PWM current control circuit 4. Further, the current flowing through the injector coil 40 is switched between forward and reverse in accordance with the pulse commands P ₁ , P ₃ , P ₃ ′ etc. given from the current command switching generation circuit 5.

The operation of the injector drive circuit shown in FIG. 1 is shown in FIG. When the injector pulse command P ₁ required for the time required for fuel injection (T _INJ ) is given, the injector current command I _{INC is set} in order to speed up the operation time of the injector.
For t ₂ hours, the injector current I _INJ is increased to flow the peak current i _P. Since the rise time t ₁ of the current is determined by the time constant of the injector coil and the power supply voltage, that is, the voltage of the booster circuit, the higher the voltage, the better.

Further, in order to make the response time of the injector constant, current control is performed so that the peak current i _{P of the} injector is made constant for t _p time. After t ₂ hours have elapsed since the injector opened the valve, the injector current command I _INC is made smaller and the holding current i _H that allows the injector to maintain the valve open state is flowed to control it to a constant value.

When the injector pulse command P ₁ is turned off, the drive circuit 2 is operated for t ₃ time by the pulse command P ₃ and the current flowing through the injector is passed in the opposite direction to accelerate the demagnetization of the exciting circuit of the injector and the response of the valve closing operation. Improve.

Returning to FIG. 1, details of specific circuits of each unit will be described below. A detailed circuit of one embodiment of the booster circuit 1 is shown in FIG. IC1 is a DC /
This is a DC converter IC, and its function can be realized by adding the peripheral circuit shown in FIG. In FIG. 3, C1 is a filter capacitor connected between the battery power supply voltage V _B and GND, and is V _IN which is the power supply of IC1.
And GND are connected in parallel. R1 and R2 are voltage dividing resistors which divide the power supply voltage V _B and input it to the ON / OFF terminal of the IC1 to start and stop the IC1.

R3 and C2 are resistors and capacitors that determine the oscillation frequency, and determine the frequency of the DC / DC converter using the IC1. R4 and R5 are resistors for dividing the reference voltage V _ref1 to limit the maximum duty of PWM, R
Reference numerals 5 and C3 are resistors and capacitors that determine the time constant for soft starting the IC1.

Rs is a resistor for detecting the output current of IC1, and the detection signal is input to the CL2 terminal by R6 and C4 to limit the output current of the power supply. MOSFET1 is OU of IC1
The PWM signal output from the T terminal is input to the gate through the base resistor R7 to perform ON / OFF switching operation to control the current flowing through the inductance L1.

R8 and C5 are a feedback resistor and a capacitor for feeding back the output E / 02 of the deviation amplifier built in the IC1 to the input terminal IN2 (-).

D1 is an output rectifying diode whose output divides the output voltage V _DC by VR1, R9 and R10,
The divided voltage is fed back to IN2 (-). VR1 is a variable resistor that adjusts the DC / DC output voltage setting value. C6 is an output filter capacitor.

The DC / DC converter described above, that is,
The operation of the booster circuit will be described below.

In FIG. 3, when the MOSFET 1 is turned on, a current flows from the battery voltage V _B through the inductance L.
Next, when the MOSFET 1 is turned off, the current energy flowing in the inductance L1 becomes a voltage of di / dt to charge the capacitor C6 via the jump diode D1 and output the output voltage V _DC . The output voltage V _DC is divided by the resistors VR1, R9 and R10 as described above and is fed back to the IN2 (-) terminal to be controlled to a constant voltage. Further, the output voltage V _DC can be adjusted by the variable resistor VR1.

Returning to FIG. 1, details of the drive circuit 2 are shown in FIG. In FIG. 4, MO1 to MO4 are power MOSFETs, four of which constitute a circuit called an H-blitch, and an injector coil is connected to the middle point of the blitches. MO
Reference numeral 1 is for PWM control, MO3 and MO4 are for switching current directions, and MO2 is for reverse current control.

Further, M5 to M8 are driver MOSFETs for driving power MOSFETs, each of which has an input or output resistance R
22 to R33 and Zeners ZD1 and ZD2 for protecting the gate-source of MO3 and MO4, respectively. R _SH is a power MOS element current detection resistor connected between the sources of MO1 and MO2 and GND, and outputs a current detection voltage V _INJ .

The operation of the drive circuit 2 (circuit of FIG. 4) is as follows. Injector pulse command P ₁ when (P ₁ signal obtained by inverting the P ₁ signal in Fig. 4) is given T _INJ period MO4 shown in FIG. 2 is turned ON during. Also, during that period PWM
A signal is also input and MO1 performs PWM operation. That is, PW
At the ON time of one cycle of the M signal, MO4⇒injector coil 40⇒MO due to the output voltage V _DC of the booster circuit described above.
The injector current I _{INJ is} passed through the route of 1⇒R _SH ⇒GND.

Next, when the PWM signal is turned off, the MOSFET M
O1 is turned off, and the injector current I _INJ flows as a circulating current in the closed circuit of the reverse diode of MO3 ⇒ MO4 ⇒ injector coil. Therefore, the injector current I
_{The INJ} value is the PWM duty (ON / ON + O
It can be changed by controlling FF).

Next, FIG. 5 shows an embodiment of the structure of the injector in which the injector coil 40 of the injector driven by applying the present invention is housed.

The structure and operation of the electromagnetic fuel injection valve (hereinafter referred to as an injector) will be described below with reference to FIG. The injector 3 is turned on from the drive circuit 2 described above.
The fuel is injected by opening and closing the fuel injection hole according to the -OFF signal.

The outline of the injector structure is as follows. First, the magnetic circuit includes a cylindrical yoke 31, a core 32, a plunger 33 and the like.

At the center of the core 32, there is a spring 39 for pressing a movable portion 36 including a plunger 33, a rod 34 and a ball valve 35 against the valve seat 9 of the fuel injection hole 37. An injector coil 40 for exciting a magnetic circuit is wound around a bobbin 41, connected to a terminal 42, and further connected to the drive circuit shown in FIG. 4 via an external connection terminal 43. Fuel is injected from the fuel injection hole 37 through the inflow passage 44, the lower passage 45, and the fuel passage 46.

The operation of the injection valve configured as described above will be described below.

The injector 3 is an injector coil 40.
The movable portion is operated by the electrical ON-OFF signal given to the fuel injection hole 37 to inject fuel. The electric signal is given to the injector coil 40 as a pulse. When a current is applied to the injector coil 40, the core 3
2, the yoke 31, and the plunger 33 constitute a magnetic circuit, and the plunger 33 is attracted to the core 32 side. When the plunger 33 moves, the ball valve 35 integrated with the plunger 33 also moves and opens the fuel injection hole 37.

Fuel flows into the injector through the inflow passage 44 by a fuel pump (not shown), and the lower passage 4
5, through the gap between the rods 34 and the fuel passage (groove) 50,
When the valve is opened, it is injected into the intake pipe through the fuel injection hole 37. When the injector coil 40 is deenergized, the movable part 36
Is pushed by the spring 39 to move to the valve seat 38 side, and the ball valve 35 closes the fuel injection hole 37.

As described above, it can be seen that the injector coil 40 is controlled by the drive circuit 2 (detailed circuit is shown in FIG. 4).

Returning to FIG. 1, a detailed circuit of the PWM current control circuit 4 for providing the PWM signal to the drive circuit 2 is shown in FIG.
In FIG. 6, IC2 is a PWM control IC, and the function of each terminal is as follows. V _IN is a terminal for inputting the V _B voltage of the power source, and GND is a terminal for inputting the GND of the power source. V _ref2 is a reference voltage output terminal created inside the IC. By _applying a voltage to the output of the resistor R19 and the capacitor C11 connected in series and inputting the intermediate point to RT / CT, the triangular wave oscillator inside the IC is generated. Constitute. C9 is a filter capacitor.

R18 and C13 are internal deviation amplifier feedback resistors and capacitors, which are the input F of each deviation amplifier.
B is connected to the output COMP terminal. The FB terminal is an input terminal for the analog signal current command I _INC .
D2, D3, R17 and C10 are soft start circuits for gradually increasing the pulse width of PWM. R20 and R21 are voltage dividing resistors, C12 is a filter capacitor, and
The current detection voltage V _INJ described in FIG. 4 is _divided and a feedback signal is input to the current detection input terminal CS. With the above structure, the circuit of FIG. 6 functions as a PWM current control circuit.

That is, the current command I of analog signal is input to IC2.
_{When INC} is input, the PWM signal is output from the OUT terminal. When the signal is applied to the drive circuit 2 shown in FIG. 4, a current flows through the injector coil 40. The current is detected as the voltage V _INJ and is fed back, so that
Circuit operates as a current control circuit. Therefore, the injector current is controlled based on the input current command I _INC .

Returning to FIG. 1, the current command switching generation circuit 5
The details of are shown in FIG. The circuit shown in FIG. 7 is a current command generation circuit for realizing the operation waveform shown in FIG. In FIG. 7, IC3-1 and IC3-2 are monostable multi, and a resistor R1 that determines the output time of an output pulse command (signal).
2, R13 and capacitors C7 and C8.

M2 to M4 are MOSFETs and resistors R14 to R16.
Are connected. VR2 and VR3 are variable resistors for setting the level of the current command value.

Next, the circuit operation will be described with reference to the operation waveforms in FIG. As shown in FIG. 2, when an injector pulse command P ₁ is issued from an engine control controller (not shown), the injector current command turns on M2 of the MOSFET and turns off M3. The output current command I _INC is generated as follows. The V _ref2 voltage of the reference voltage is _divided by the VR2 level setting variable resistor, and the command value corresponding to the holding current i _H is generated as the current command value I _INC for the T _INJ time when the pulse command P ₁ is input.

At the same time, the pulse command P ₂ is output for t ₂ time and M4 is turned on to increase the current command to increase the peak current i.
By injecting _P , the injector operation immediately after turning on is accelerated. After the lapse of t ₂ time, the holding current i _H becomes necessary to maintain the ON state of the injector as described above.
The magnitude of the current command value can be adjusted by the variable resistors VR2 and VR3.

Next, the injector pulse command P1 is turned off.
Then, the pulse command P3 is generated for t3 time, and a reverse current is supplied to the injector to accelerate the OFF operation.

FIG. 8 shows the relationship between the injector current and the valve moving amount L _INJ by expanding the time axis when the injector is ON. When the injector pulse command P ₁ is generated, the injector current I _INJ rapidly rises, and current control is performed so that the peak current i _P becomes constant after t ₁ hours. The time t ₁ is preferably as short as possible and depends on the voltage of the booster circuit 1 and the electrical time constants of the injectors such as L and R.

The operation of the injector is such that when a peak current i _{P is} passed through the injector coil, T _{S is} caused by mechanical friction or the like.
The operation is started with a time delay and the valve is opened.

After the time T _a, it hits the stopper, vibrates, stabilizes after the time T _ON , and the valve is opened. The peak current i _P of the injector current I _INJ is controlled to be constant by lowering it to a holding current i _H necessary for holding the injector as it is after flowing for t ₂ time until the valve is completely sucked to the valve opening side. I do.

As described above, according to the present invention, the peak current i _P and the holding current i _H of the injector can be changed by changing the current command with only one power supply, and both currents can be controlled to be constant. .

FIG. 9 is a detailed circuit diagram of another embodiment of the booster circuit shown in FIG. 3, which is used when it is necessary to further increase the boosted voltage. The difference from Fig. 3 is T
Only _one transformer is provided, and the output voltage V _DC can be arbitrarily set by changing the primary and secondary boosting ratios.

FIG. 10 is a detailed circuit diagram of another embodiment of the current command switching generation circuit shown in FIG. 7, and its purpose is to shorten the T _ON time of the injector valve shown in FIG. The means for reducing the vibration of the valve is shown.

10 is different from FIG. 7 in the IC.
A monostable multivibrator of 3-4 and IC3-5 is added, and capacitors C14 and C15 and resistors R34 and R35 that set the time width of the pulse are provided.
Each pulse command P _a to the injector pulse command _{P 1, P b, P c} , the relationship between P ₂ shown in FIG. 11. I of FIG.
C3-1, IC3-4, P _a using a IC3-5, P _b,
A pulse command P ₂ can be obtained by generating a pulse of P _c .

FIG. 12 shows operation waveforms when the injector is operated using the circuit of FIG. The operation of the injector in this case is as follows. The pulse command P ₂ based on pulse command P ₁ flowing T ₃ hours outputted injector peak current i _P, once the injector valve starts to move the injector peak current i _P decreases t ₄ hours valve collides with the stopper Soften what you do. That is, soft landing is performed. This can reduce the vibration of the valve that occurs after the valve is fully opened. Further, when the valve is fully opened, the peak current i _P is flowed again to ensure the full opening of the valve, and then the injector current is lowered to the holding current i _H state.

With the above-described method, the vibration of the moving amount L _INJ of the injector valve shown in FIG. 12 is reduced and stabilized, so that the time during which the injector is turned on, that is, T _ON can be shortened.

FIG. 13 shows another embodiment. In FIG. 13, the booster circuit 1, the drive circuit 2, the PWM current control circuit 4, and the current command switching generation circuit 5 are the same as those described with reference to FIGS. The difference is MOSFET
It means that M9 and diode D5 of
The M9 drain of the ET is connected to the positive terminal of the battery B, and the source is connected to one end of the injector coil 40 via the diode D5.

The circuit operation will be described with reference to FIG. When the injector pulse command P ₁ is given, the pulse command P ₂ is generated, and while P ₂ is generated, the injector starting current I _P is made to flow through the injector coil 40 from the boosted voltage V _DC of the output of the booster circuit. Next, when the pulse P ₂ is turned off, the signal of P ₁ is applied to the gate of M 9 of the MOSFET while P ₁ is generated, so that M 9 is maintained in the ON state and the battery B
The holding current I _H is continuously supplied to the injector coil 40 from the voltage of 12 V through the MOSFET M9 and the diode D5. In this way, the starting current is from the booster circuit and the holding current is 1
It is also possible to automatically switch and flow from the 2V voltage. In this case, the peak value of each current is, of course, controlled to be constant.

[0055]

As described above, according to the present invention, it is possible to perform high-speed control of the injector in the injector drive device for a vehicle. Further, since the operating speed and holding force of the injector valve can be made constant, the on-off valve control of the injector can be performed with less influence of the drive current due to temperature change.

Further, since the peak current value and the holding current value are controlled to be constant values, it is possible to reduce the characteristic change due to the variation of the injector.

[Brief description of drawings]

FIG. 1 is a block diagram of a control system of an injector drive device for explaining the present invention.

FIG. 2 is an operation explanatory diagram illustrating a circuit operation of the present invention.

FIG. 3 is a detailed circuit diagram of an example circuit of the booster circuit 1.

FIG. 4 is a detailed circuit diagram of an example circuit of a drive circuit 2.

FIG. 5 is a structural diagram for explaining the structure of an embodiment of an injector to which the present invention is applied.

FIG. 6 is a detailed circuit diagram of a circuit of an embodiment of a PWM current control circuit 4.

FIG. 7 is a detailed circuit diagram of an example circuit of a current command switching generation circuit 5.

FIG. 8 is an operation explanatory diagram when the injector is applied to which the present invention is applied.

FIG. 9 is a detailed circuit diagram of another embodiment circuit of the booster circuit 1.

FIG. 10 is a detailed circuit diagram of another embodiment circuit of the current command switching generation circuit 5.

FIG. 11 is an input pulse operation waveform of a circuit of another embodiment of the current command switching generation circuit 5.

FIG. 12 is an operation explanatory diagram of a detailed circuit diagram of another embodiment circuit of the current command switching generation circuit 5.

FIG. 13 is a block diagram of the overall circuit configuration for explaining another embodiment of the present invention.

FIG. 14 is an operation explanatory view explaining the circuit operation of another embodiment of the present invention.

[Explanation of symbols]

1 ... Booster circuit, 2 ... Drive circuit, 3 ... Injector, 4 ...
PWM current control circuit, 5 ... Current command switching generation circuit,
40 ... Injector coil.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoko Nakayama 7-1-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Mitsuru Watanabe 2520 Takaba, Hitachinaka-shi, Ibaraki Stocks Company Hitachi, Ltd. Automotive Equipment Division (56) References JP-A-10-9027 (JP, A) Actual Kaihei 5-87247 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02D 41/20 330 F02D 41/34 F02M 51/06

Claims (11)

(57) [Claims] 1. A) battery, B). A high voltage source for boosting and outputting the voltage of the battery, C). A valve opening signal generating circuit for generating a valve opening pulse signal according to the operating state of the engine, D ). 1st which connects while the valve opening pulse signal is generating, connects so that the said high voltage power supply and the coil of a fuel injection valve can energize
E). An ON-OF connected to the first semiconductor switching element in series to control the current flowing through the coil.
F ) A second semiconductor switching element that receives a pulse signal with an adjustable duty to cut off conduction is provided, and F ). The injector drive circuit is an H-blitch power circuit.
And PWM current control circuit and current command switching generation circuit etc.
A drive device for a fuel injection valve for an internal combustion engine configured . 2. The device according to claim 1, wherein the first semiconductor switching element is connected between the high voltage source and a coil, and the second semiconductor switching element is connected between the coil and a ground.
Of a fuel injection valve for an internal combustion engine, to which the semiconductor switching element of claim 1 is connected. 3. The method according to claim 1 or 2,
A drive device for a fuel injection valve for an internal combustion engine, wherein the second semiconductor switching element is configured to be conductively interrupted by a high duty signal and then electrically interrupted by a low duty signal in a predetermined section immediately after the rise of the valve opening pulse signal. . 4. The fuel for an internal combustion engine as set forth in claim 1, wherein a reverse connection circuit for supplying a current in a reverse direction to that of the coil is provided to the coil for a predetermined period following the rear end of the valve opening pulse. Drive device for injection valve. 5. The circuit according to claim 4, wherein the reverse connection circuit includes two semiconductor switching elements, a third semiconductor switching element and a fourth semiconductor switching element, and the third semiconductor switching element includes the first semiconductor element and the semiconductor switching element. Fuel injection for an internal combustion engine, which is connected in parallel to a series connection circuit of a coil, and the fourth semiconductor switching element is connected in parallel to a series connection circuit of the coil and the second semiconductor switching element. Valve drive. 6. A). Switching means for interrupting conduction by a pulse signal given from a control device of the internal combustion engine; and B). Another switching means for interrupting conduction by a signal given by a PWM (pulse wide modulator). A drive device for a fuel injection valve for an internal combustion engine configured to supply a current according to the on-duty of another switching device to the coil of the fuel injection valve while the switching device is conducting. 7. A). A capacitor charged up to a voltage higher than that of an on-vehicle battery, B). A series resonance circuit including this capacitor and a coil of a fuel injection valve, C). A device for driving a fuel injection valve for an internal combustion engine, comprising: a means for establishing a medium; and a current control means for controlling a current flowing through the series resonance circuit by an output from the PWM circuit. 8. The internal combustion engine according to claim 2, wherein the current command switching generation circuit gives a current command value to the PWM current control circuit, and the H-blitch power circuit PWM-controls the current flowing through the injector. organ
Device for fuel injection valve for automobile. 9. The injector according to claim 1, wherein the booster circuit, which is a power source of the injector, is a single power source, and a peak current at the time of starting the injector and a holding current at a steady state are switched by switching a current command value, and , Internal combustion characterized in that each current value is controlled to be constant according to a command value
Drive device for engine fuel injection valve. 10. The internal combustion engine according to claim 3, wherein, when the injector current is OFF, the H-blit power circuit is switched to cause a reverse current to flow in the injector coil to accelerate the OFF operation.
Device for fuel injection valve for automobile. 11. The control according to claim 4, wherein during a period in which a peak current flows when the injector is started, a control pulse signal is turned on and off to increase / decrease the current to reduce the bound when the injector is opened. A drive device for a fuel injection valve for an internal combustion engine, which is characterized by being performed .