JPH06264805A - Fuel injection valve driving control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent duplication of compression stroke sequential injection and intake stroke injection in those cylinders having adjacent number of ignition. CONSTITUTION:Flyback energy is generated so as to charge piezoelectric element by cutting off current which flows in the primary coil of a flybock transformer at a specified timing, and piezoelectric elements (1-N) ore formed to make discharge at a specified timing, and a fuel injection valve operated by the piezoelectric elements is openly/closely controlled (B). A plural number of fuel injection valves 1, 2...N for a plural number of cylinders ore openly/ closely controlled in a specified order (D), and at least one of injection timing is corrected to be shifted when the compression stroke injection end timing of a specific cylinder and at intake stroke injection end timing of another cylinder come close to each other, in a fuel injection valve driving controller of an internal combustion engine equipped with a device (A) for controlling each fuel injection valve in such a way as making injection plural times in on intake stroke and a compressed stroke per one cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve drive control device for an internal combustion engine, and more particularly to a fuel injection valve drive control device for an internal combustion engine using a piezoelectric element actuator.

[0002]

2. Description of the Related Art A fuel injection valve device for an internal combustion engine using a piezoelectric element actuator has recently attracted particular attention because it can be expected to operate at high speed. FIG. 6 is a conceptual configuration diagram showing an example of the configuration of a fuel injection valve device for an internal combustion engine using such a piezoelectric element, in which the fuel injection valve 100 is provided.
The piezoelectric element 101 is used as a driving actuator therein. That is, when the piston 102 rises and the pressure of the hydraulic oil 103 becomes equal to or lower than the pressure received by the pressure receiving surface 106 according to the contraction of the piezoelectric element 101, the push rod 104
Rises, the fuel in the pressure chamber 105 is pressurized and injected from the injection hole 108, and when the piezoelectric element 101 expands, the pressure of the hydraulic oil 103 increases and the injection hole 108 closes due to the effect opposite to that during compression. Injection stops. In order to ensure the opening and closing of the valve by the above operation, for example, a disc spring 107 is provided in the hydraulic oil chamber.

As a fuel injection valve using a piezoelectric element actuator, contrary to the one shown in the figure, there is also a type that injects fuel when the piezoelectric element expands and sucks fuel when the piezoelectric element contracts, and these are in a fuel injection state. The fuel injection amount is determined by the duration of the contraction or extension of the piezoelectric element.
There is also a fuel injection valve in which the fuel is pumped by a piston that moves up and down according to the expansion and contraction of the piezoelectric element to inject fuel, but this type determines the fuel injection amount based on the number of times the piezoelectric element expands and contracts. It will be.

FIG. 7 is a circuit diagram showing the principle configuration of a flyback type drive circuit suitable as a piezoelectric element drive circuit in the fuel injection valve shown in FIG.
Is a piezoelectric element (PZT) corresponding to the piezoelectric element 101 as a driving actuator in FIG. 6, 202 is a flyback transformer, 203 is a drive transistor, 204 is a charging switch, 205 is a backflow prevention diode for charging, and 2 is
Reference numeral 06 is a discharge switch, 207 is a discharge backflow prevention diode, 208 is a discharge coil, and 210 is an electronic control unit E.
CU. Then, FIG. 8 shows operation waveforms in the normal operation of the drive circuit.

The operating principle of this flyback drive circuit is that the flyback transformer 202 is connected to the secondary side by flyback energy generated on the secondary side of the transformer when the current flowing through the primary coil of the flyback transformer 202 is cut off. The piezoelectric element (PZT) 201 is charged, the piezoelectric element 201 is expanded to stop the injection, and the charge of the piezoelectric element 201 is discharged through the discharge coil 208, and the piezoelectric element 201 is contracted to inject fuel. The piezoelectric element 201
Is in a contracted state during the period from discharge to the next charge, and the fuel injection amount is determined by the time width.

In the operation waveforms shown in FIG. 8, signals 211 and 21 are included.
2, 213 and 214 are an injection signal, a coil energization signal (hereinafter also referred to as a dwell signal as described later), a PZT discharge signal and a PZT charge signal,
In the electronic control unit ECU 210, a coil energization signal for supplying a necessary amount of energy to the piezoelectric element 201, that is, a dwell signal 21 from the fuel injection signal 211 indicating the fuel injection time calculated according to the operating state of the engine.
2. PZT discharge signal 213 and PZT charge signal 21 synchronized with the rising and falling of the injection signal 211, respectively.
4 is formed.

Coil energization signal or dwell signal 212
Has its falling edge coincident with the falling edge of the injection signal 211, and its rising edge is a conducting time between rising and falling edges, that is, dwell time, which is a constant time during which constant charging energy can be supplied to the piezoelectric element 201. Width, eg 4 to 5
It is set to be milliseconds. As a result, the amount of expansion of the piezoelectric element 201 becomes constant, the degree of change in operating hydraulic pressure becomes constant, and as a result, the fuel injection amount per unit time, that is, the fuel injection rate becomes constant, enabling uniform fuel injection control. It is a thing. Further, the PZT discharge signal 213 and the PZT charge signal 214 are respectively supplied to the piezoelectric element 20.
This is an on / off control signal for the discharge switch 206 and the charge switch 204 for instantaneously achieving discharge and charge of No. 1, and both of them have a time width of, for example, about 200 microseconds.

First, from the electronic control unit ECU 210
By the coil energization signal 212 supplied, t₁At the point
Drive transistor 203 is turned on and the flyback
The primary current I is applied to the primary coil of the transformer 202.₁215
Flowing. At this time, the primary current I ₁Is the primary in of the transformer
Dactance is L₁If so, dI₁/ Dt = V_B/ L ₁
(V_B: Power supply voltage) rises with a slope. That
At the end of the coil energization period, that is, the coil energization signal
212 fall t₃The primary current at the time point is I_DTo
And the flyback transformer 202 has 1/2 (L₁・ I
_D ²) Will be stored. This
Between t₁~ T₃In the initial stage of the charging switch 204
Both the discharge switch 206 and the discharge switch 206 are off.
Also, the piezoelectric element 201 was not charged in the previous charging cycle.
It is in a stretched condition. Piezoelectric element 2 at this time
The terminal voltage of 01, that is, the PZT voltage 216 is E_C= I
_D・ √ (L₁/ C) (C: capacitance of the piezoelectric element 201)
It has risen to a value that reaches, for example, a value of about + 600V
To do.

After energizing the flyback coil, the injection signal 2
When the rising edge of 11, that is, the time point t ₂ is reached, the PZT discharge signal 213 is applied from the electronic control unit ECU 210 to the discharge switch 206, the discharge switch 206 is turned on, and the charge of the piezoelectric element 201 is discharged through the discharge coil 208. To be done. As a result, the piezoelectric element 201 contracts, opens the injection hole 108 of the fuel injection valve 100 in FIG. 6, and starts fuel injection. During this transition, the capacitance C of the piezoelectric element 201 and the discharge coil 208 form a resonance circuit, and a resonance current flows to cause the piezoelectric element 201 to flow.
Is instantaneously discharged, and the PZT voltage 216, which is the terminal voltage, drops sharply. Then, the backflow prevention diode 207 cuts off the resonance current, and the discharge ends. This transient change is about 100 microseconds and ends within the PZT discharge signal width of about 200 microseconds. For this reason, the PZT voltage 216 has its swing in the positive direction cut off as shown by the dotted line, and a certain negative voltage,
For example, the voltage settles to −200V, and the piezoelectric element 201 remains in the contracted state corresponding to this state. At this time,
Depending on the contraction state of the piezoelectric element, or according to the valve opening determined by the mechanism, the fuel injection will be continued at a constant rate as shown by the fuel injection rate 217 in FIG. .

Next, when the injection signal 211 falls, that is, at time t ₃ , the coil energization signal 212 falls,
The drive transistor 203 is turned off, and the PZT charge signal 214 is applied from the electronic control unit ECU 210 to the charge switch 204 to be turned on. When the drive transistor 203 is turned off, the primary current I ₁ is cut off, a flyback pulse is generated on the secondary side of the flyback transformer 202, and the energy accumulated during the energization period, that is, the dwell time is released. At this time, since the charging switch 204 is turned on, the flyback energy charges the piezoelectric element 201. In the transient state, the secondary inductance of the flyback transformer 202 and the electrostatic capacitance C of the piezoelectric element 201 form a resonance circuit, and a resonance current flows, and the piezoelectric element 201 is instantly charged and expanded by the flyback energy. . As in the case of discharging, the reverse current is generated by the reverse current prevention diode 20.
5, the piezoelectric element 201 is maintained in the charged state by the flyback energy, that is, the expanded state corresponding to the energy amount. as a result,
The terminal voltage of the piezoelectric element 201, that is, the PZT voltage 216
As shown in FIG. 8, the voltage rapidly rises in the positive direction and reaches the above-mentioned E _C , for example, +600 V, and is maintained at that voltage. The secondary inductance of the flyback transformer 202 is set to be approximately the same as that of the discharge coil 208, and therefore, this transient change is also about 100.
It is a microsecond, and the PZT charge signal width ends within about 200 microseconds. Thus, fuel injection rate 2
Also in 17 as shown, the injection is rapidly stopped and the injection valve is closed.

The flyback type drive circuit shown in FIG. 7 operates as described above to drive and control the fuel injection of the fuel injection valve in accordance with the injection signal having the injection time corresponding to the operating state of the engine, thereby making the target empty space. Fuel injection control such as fuel ratio control can be realized. FIG. 9 is a circuit block diagram showing the principle configuration of a fuel injection valve drive control system for a 4-cycle 4-cylinder engine to which a fuel injection valve using a piezoelectric element driven by the above-mentioned flyback drive circuit is applied. . Here, one flyback transformer unit 220 is commonly used, and piezoelectric elements for fuel injection valve operation for four cylinders are selectively driven in a predetermined order by forming a flyback drive circuit. Piezoelectric element circuit portions 221 to 224, which are the remaining portions of the flyback drive circuit, are configured and provided in a similar manner for four cylinders, as shown in the figure. The same components as those in FIG. 7 are used as the components of the flyback transformer unit 220 and the piezoelectric element circuit units 221 to 224, and as an example, the flyback transformer 202, the drive switch (transistor) 203, and the reverse charging flow. It is shown that the prevention diode 205 is provided in the common flyback transformer section 220.

FIG. 10 is a time chart schematically showing operation signal waveforms for each of the cylinders # 1 to # 4 in the fuel injection valve drive control system for this four-cylinder engine. In the figure, a signal 231 is a coil energization signal, that is, a dwell signal for storing energy in the coil of the flyback transformer in the drive circuit, that is, a dwell signal, a signal 232 is an ejection signal, and a signal 233 is a dwell signal 2.
31 and the terminal voltage of the piezoelectric element driven based on the ejection signal 232, that is, the PZT voltage V _PZT . These signals for each cylinder are respectively labeled with cylinder numbers, and the operation sequence of each cylinder follows the ignition sequence of a normal four-cylinder internal combustion engine.

FIG. 11 (1) shows a schematic structure of an example of an actual four-cylinder piezoelectric element drive circuit, in which one flyback transformer A or B is used for four cylinders #.
Piezoelectric element # 1PZT for driving a fuel injection valve for 1 to # 4
~ # 4PZT is commonly driven, and for each cylinder, in the intake stroke so as to generate a good air-fuel mixture,
Further, a flyback transformer A for the intake stroke and a flyback transformer B for the compression stroke are provided in order to perform fuel injection twice in the compression stroke so as to form a rich air-fuel mixture around the plug during ignition. There is. FIG. 11 (2)
Is the drive waveform of each flyback transformer (1
It is a time chart which shows the following electric current in relation to a crank rotation angle ( _CA ).

FIG. 12 is a more detailed time chart showing the timing of intake and compression stroke injection for the four cylinders # 1 to # 4. In the figure, an electronic control unit ECU (FIG. 7) is shown.
210), the PZT injection signal (2) for intake injection and compression injection, and the flyback energization signal, that is, the dwell signal (3), which is the energization signal for the primary coils of the flyback transformers A and B, PZ as a result
The T voltage waveform (1) is shown demonstrating the time relationship. It should be noted that, here, the case where both the intake injection and the compression injection are executed for each cylinder and the intake injection time is slightly long is shown, but in this case, the control is performed at a medium engine load, that is, a medium load. For other engine loads, from the required fuel injection amount and the generation state of the air-fuel mixture, for example, at a light load, fuel injection is executed only in the compression stroke, and at a high load. Means that fuel injection is executed only in the intake stroke.

In the fuel injection valve drive control device for an internal combustion engine of an automobile as described above, depending on the operating state of the engine,
The amount of fuel injection is controlled constantly and in a wide range,
A parameter indicating the operating state of the engine, such as the accelerator opening
Controls the timing and time of fuel injection by forming an injection signal according to the fuel injection amount Q _INJ determined by ACCP and engine speed NE, and adjusting the dwell signal and PZT discharge and charge signal based on it. Then, the actual fuel injection amount for each cylinder of the engine is controlled.

[0016]

The above-mentioned compressed row
Of a two-injection type internal combustion engine of stroke injection and intake stroke injection
In the fuel injection valve drive control device, as shown in FIG.
And, for example, the end timing of the compression process injection of the # 1 cylinder
The end timing of the intake stroke injection of the other # 3 cylinder approaches
Then, charging of the piezoelectric elements in the fuel injection valves of both cylinders is performed.
Both piezoelectric elements are charged at
Current I flowing through the elements simultaneously_PZT(# 1) and I _PZT(# 3)
The distribution is biased, for example, I_PZTThere are many (# 1),
And I_PZTDistortion may occur so that (# 3) is reduced.
It As a result, the PZT voltage V in the figure_{PZ T}As seen in
To V_PZT(# 1) is big because it gets energy from # 3 cylinder
Kiku, V_PZT(# 3) has energy taken up by # 1 cylinder
Will be smaller.

If the end timings of the compression stroke injection and the intake stroke injection of the two different cylinders overlap each other, the energy supply source by the intake injection flyback coil and the compression stroke injection flyback coil corresponding to each injection is generated. It will be crossed and it will not be possible to evenly distribute energy.
In a cylinder equipped with a fuel injection valve that is driven by a piezoelectric element on the side where the amount of energy supplied is small, the amount of fuel injection decreases, causing a problem of engine misfire.

In order to solve such a problem, the present invention can be corrected so as to avoid the overlap of the dwell-off time for the compression stroke injection and the intake stroke injection in the cylinders having the adjacent ignition orders. An object of the present invention is to provide a fuel injection valve drive control device for an internal combustion engine.

[0019]

According to the present invention, a piezoelectric element is connected to a secondary coil of a transformer, and a current flowing through the primary coil at a predetermined timing, as conceptually shown in FIG. By shutting off, the flyback energy is generated in the secondary coil to charge the piezoelectric element, and the piezoelectric element is discharged at a predetermined timing,
(B) for controlling opening / closing of a fuel injection valve operated by the piezoelectric element, wherein a plurality of fuel injection valves (1, 2, ..., N) for injecting fuel into a plurality of cylinders are predetermined. In a fuel injection valve drive control device for an internal combustion engine, which performs open / close control (D) in sequence, and controls (A) each fuel injection valve to be injected multiple times in an intake stroke and a compression stroke in one cycle, a specific cylinder When the compression stroke injection end timing of (1) and the intake stroke injection end timing of the other cylinders are close to each other, the injection timing is corrected (C) so that at least one injection timing is shifted.
The injection timing is corrected by shifting the intake stroke injection end timing in a direction away from the compression stroke injection end timing.

[0020]

According to the above construction, since the injection end timings of the intake stroke injection and the compression stroke injection do not overlap,
The energy charged in the piezoelectric element in each injection valve is evenly distributed, and the fuel injection amount in each injection valve can be controlled to a desired amount.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A configuration for avoiding the above-mentioned injection overlap will be described below with respect to an embodiment of a fuel injection valve drive control device for an internal combustion engine according to the present invention. As the PZT drive circuit, the configuration shown in FIG. 11 is used. As described above, the flyback coil A is in charge of intake stroke injection for the # 1 to # 4 cylinders, and the flyback coil B is for compression. In charge of stroke injection. In the double injection control system in which injection is required in the intake stroke and the compression stroke, # 1 → # 3
→ # 4 → # 2, in the process of progressing combustion, when the end time of the compression stroke injection of the preceding cylinder, for example, # 1 and the intake stroke injection of the following cylinder, for example, # 3, overlap between consecutive cylinders. Occurs.

FIG. 2 shows such # 1 compression stroke injection and #
3 is a time chart for explaining a correction control method according to the present invention that avoids the overlap when the end timings of the three intake stroke injections overlap. In avoiding overlap, the intake stroke injection is for producing a good mixture, and the compression stroke injection is for forming a rich mixture around the plug just before ignition. Since the stroke injection is relatively insensitive to combustion, the intake stroke injection is shifted to the advance side or the retard side in consideration of the margin time Tc according to the proximity condition.

As shown in FIGS. 2A and 2B, the dwell signal and the injection signal for the compression stroke injection of the # 1 cylinder, and
The dwell signal and the injection signal for the intake stroke injection of the three cylinders approach each other at substantially the same time. Here, for simplicity, the time parameter in those signals is # 2.
It is represented with reference to TDC timing. That is, regarding the dwell signal for the compression stroke injection of the # 1 cylinder, the dwell on time: TDWLS # 1, the dwell time: TDWL,
Dwell off time: TDWLE # 1 For injection signal for compression stroke injection of # 1 cylinder,
Injection start time: TAINJ # 1, injection time: TINJ # 1, again #
Regarding the dwell signal for the intake stroke injection of 3 cylinders,
Dwell on time: TDWLS # 3, dwell time: TDWL, dwell off time: TDWLE # 3 For injection signal for intake stroke injection of # 3 cylinder,
Injection start time: TAINJ # 3, injection time: TINJ # 3.

Therefore, in the correction control according to the present invention, first, the dwell off time for the compression stroke of the # 1 cylinder and the # 3 cylinder are set.
Take the difference from the dwell off time for the intake stroke of the cylinder. That is, ΔT = TDWLE # 1-TDWLE # 3 is calculated. Next, whether or not the dwell-off times for both injections are close to each other and the condition of the close-up, that is, the direction of the close-up, are judged by observing the magnitude relationship between the dwell-off time difference ΔT and the margin time Tc and the sign thereof, and Take appropriate measures. The margin time Tc is, for example,
As described above, the time width of the PZT charge signal is about
That is, about 200 microseconds can be used.

Countermeasure: When Tc ≧ ΔT ≧ 0, that is, when # 3 is close to # 1 on the advance side, the dwell off time of # 3 is set to # 1 as shown in FIG. 2C. Advances by an amount corresponding to Tc time. That is, TDWLE # 3 = TDWLE # 1−Tc = TDWLE # 3− (Tc−ΔT) is set to the advance side. Similarly, the dwell-on time and injection start time of # 3 are also shifted to the advance side. That is, TDWLS # 3 = TDWLS # 3 -− (Tc−ΔT) TAINJ # 3 = TAINJ # 3− (Tc−ΔT).

Countermeasure: When 0> ΔT ≧ −Tc, that is, when # 3 is close to # 1 on the retard side, as shown in FIG. 2D, the dwell off time of # 3 is changed to #. From 1, the angle is delayed by a time corresponding to Tc time. That is, TDWLE # 3 = TDWLE # 1 + Tc = TDWLE # 3 + Tc + ΔT, and shift to the retard side. Similarly, the dwell-on time and injection start time of # 3 are also shifted to the retard side. That is, TDWLS # 3 = TDWLS # 3 + Tc + ΔT TAINJ # 3 = TAINJ # 3 + Tc + ΔT.

By the above measures, the dwell-off time for the compression stroke injection of the # 1 cylinder and the dwell-off time for the intake stroke injection of the # 3 cylinder can be shifted so as to be the Tc time interval, and both injections can be performed. Therefore, it is possible to completely avoid the overlap of the piezoelectric element charging time. FIG. 3 is a timing chart for explaining the operation of the embodiment of the fuel injection valve drive control device for the internal combustion engine according to the present invention, and FIGS. 4 and 5 are flowcharts showing an example of software for realizing the same. is there. Here, a case where the compression stroke injection of the # 4 cylinder and the intake stroke injection of the # 2 cylinder are close to each other will be described as an example.

First, in the base routine of FIG. 4, basic injection output data and dwell output data for compression stroke injection and intake stroke injection are calculated in advance, for example, at fixed intervals of 5 milliseconds. That is, in the calculation step a, for compression stroke injection (A2) and intake stroke injection (A1)
Of basic injection output data, that is, injection start timing TAIN
Calculate JA1, TAINJA2 and injection time TINJA1, TINJA2 based on accelerator position ACCP and engine speed NE: TAINJA1 = f (ACCP, NE) TAINJA2 = f (ACCP, NE) TINJA1 = f (ACCP, NE) TINJA2 = f (ACCP, NE) Next, in the calculation step b, for compression stroke injection (A2)
And basic dwell output data for intake stroke injection (A1),
That is, the dwell start time TDWLSA1, TDWLSA2 and dwell time TDWL, the reference 30 ( _CA ) angular position CASET are calculated: TDWLSA1 = f (TAINJA1, TINJA1, NE) TDWLSA2 = f (TAINJA2, TINJA2, NE) CASET = f (TDWLSA2 , NE) TDWL = constant (ms) FIG. 5 shows a 30 ( _CA ) interrupt routine executed every 30 ( _CA ) for shifting the dwell-off time. Then, FIG. 3 shows the time relation of the data handled therein. First, in step c, it is determined whether or not it is the timing to output the injection and dwell signals (CASET?). If Yes, in step d, among the dwell data for the fuel injection valves of the cylinders adjacent to each other in the injection order,
The difference ΔT between the dwell-off time TDWLEA2 for the compression stroke injection for the fuel injection valve of the preceding cylinder and the dwell-off time TDWLEA1 for the intake stroke injection for the fuel injection valve of the following cylinder is calculated. Then, in step e, Δ
It is determined whether T is in the positive direction of zero or more. In addition,
When ΔT is equal to or longer than the margin time Tc, the correction according to the present invention is unnecessary, but a flow for that purpose is not shown.

If the determination in step e is Yes, the process proceeds to step f and the dwell on / off time TDWLEA1 / TDWLSA1 and the injection start time TAIN for the fuel injection valve of the subsequent cylinder
With respect to JA1, the advance angle correction process for the margin time Tc is executed from that for the fuel injection valve of the preceding cylinder. At this time, the injection time TINJA1 is not changed. That is, the correction process is executed as follows.

TDWLEA1 (i) = TDWLEA1 (i)-(Tc-ΔT) TDWLSA1 (i) = TDWLSA1 (i)-(Tc-ΔT) TAINJA1 (i) = TAINJA1 (i)-(Tc-ΔT) TINJA1 ( i) = TINJA1 (i) If the judgment in step e is No, the process proceeds to step g, and the dwell on / off time TDWLEA1 / TDWLSA1 and the injection start time TAINJA1 for the fuel injection valve of the subsequent cylinder are compared with those of the preceding cylinder. The retard correction process for the margin time Tc is executed from the fuel injection valve. At this time, the injection time TINJA1 is not changed. That is, the correction process is executed as follows.

TDWLEA1 (i) = TDWLEA1 (i) + Tc + ΔT TDWLSA1 (i) = TDWLSA1 (i) + Tc + ΔT TAINJA1 (i) = TAINJA1 (i) + Tc + ΔT TINJA1 (i) = TINJA1 (i) Based on the obtained dwell data and injection data and the engine speed NE, at step h, the reference angle 30 ( _CA ) for adjacent injections, that is, the set dwell on time TA1 and TA2 from CASET, and the set injection start times TDA1 and TDA2 are set. calculate. Then, in step j, the calculated data are output together with the injection time TINJ and the dwell time TDWL.

[0032]

As described above, according to the fuel injection valve drive control system for an internal combustion engine of the present invention, the injection end of the intake stroke injection of the succeeding cylinder and the compression stroke injection of the preceding cylinder in the cylinders adjacent in ignition order is completed. Because the times do not overlap,
The energy charged in the piezoelectric element in each fuel injection valve is evenly distributed, and the fuel injection amount in each fuel injection valve can be correctly controlled to a desired amount.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a fuel injection valve drive control device for an internal combustion engine according to the present invention.

FIG. 2 is a time chart for explaining a control method for avoiding duplication based on the present invention.

FIG. 3 is a timing chart for explaining the operation of the fuel injection valve drive control device for the internal combustion engine according to the present invention.

FIG. 4 is a flowchart showing an example of software for realizing a fuel injection valve drive control device for an internal combustion engine according to the present invention.

FIG. 5 is a flowchart showing an example of software for implementing the fuel injection valve drive control device for the internal combustion engine according to the present invention.

FIG. 6 is a conceptual configuration diagram showing an example configuration of a fuel injection valve device for an internal combustion engine using a piezoelectric element.

FIG. 7 is a circuit diagram showing a principle configuration of a flyback type piezoelectric element drive circuit.

8 is a time chart showing operation signal waveforms of the flyback type piezoelectric element drive circuit of FIG.

FIG. 9 is a circuit block diagram showing a principle configuration of a fuel injection valve drive control system of a 4-cycle 4-cylinder engine to which a fuel injection valve using a piezoelectric element driven by a flyback drive circuit is applied.

10 is a time chart for explaining the operation of the fuel injection valve drive control system of the 4-cycle 4-cylinder engine of FIG.

FIG. 11 is an explanatory diagram conceptually showing the structure of an example of an actual four-cylinder piezoelectric element drive circuit.

12 is a time chart showing the timing of intake and compression stroke injection in the four-cylinder piezoelectric element drive circuit of FIG.

FIG. 13 is a time chart for explaining a state where dwell-off times overlap in a fuel injection valve drive control system for a 4-cycle 4-cylinder engine.

[Explanation of symbols]

100 ... Fuel injection valve 101, 201 ... Piezoelectric element 103 ... Hydraulic oil 104 ... Push rod 105 ... Pressure chamber 108 ... Injection hole 202 ... Flyback transformer 203 ... Drive transistor 204 ... Charge switch 205, 207 ... Backflow prevention diode 206 ... Discharge Switch 208 ... Discharge coil 210 ... Electronic control unit 211 ... Injection signal 212 ... Coil energization signal 213 ... PZT discharge signal 214 ... PZT charge signal 215 ... Primary current 216 ... PZT voltage 217 ... Fuel injection rate 221, 222, 223, 224 ... Flyback drive circuit 231 ... Dwell signal 232 ... Injection signal 233 ... PZT voltage

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Seiji Morino 1-1, Showa-cho, Kariya city, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Inventor ▲ Yoshihiro Tani, 1-chome, Showa-cho, Kariya city, Aichi prefecture Address: Nippon Denso Co., Ltd.

Claims (2)

[Claims] 1. A piezoelectric element is connected to a secondary coil of a transformer, and a current flowing through the primary coil is cut off at a predetermined timing to generate flyback energy in the secondary coil to charge the piezoelectric element. , Which controls the opening and closing of a fuel injection valve operated by the piezoelectric element by discharging the piezoelectric element at a predetermined timing, and a plurality of fuel injection valves for injecting fuel into a plurality of cylinders are arranged in a predetermined order. In the fuel injection valve drive control device for an internal combustion engine, which controls the fuel injection valves to be sequentially driven by the fuel injection valve, the fuel injection valves are controlled to be injected multiple times in the intake stroke and the compression stroke in one cycle. Distinguish the state where the injection end timing and the intake stroke injection end timing of other cylinders are close to each other, and shift at least one of the injection timings. A fuel injection valve drive control device for an internal combustion engine, comprising: 2. The fuel injection valve drive control device for an internal combustion engine according to claim 1, wherein the injection timing correction means shifts the intake stroke injection end timing in a direction away from the compression stroke injection end timing.