JPH07269404A - Fuel injection control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To surely prevent engine stalling caused in the case where a peak current can not be supplied in a fuel injection control device provided with a drive circuit for supplying the peak current for high speed valve opening at the time of starting current supply for a fuel injection valve. CONSTITUTION:In a device provided with a boosting circuit 32 for charging a high voltage to a capacitor C1 so as to supply peak currents immediately after starting current supply to solenoids L1-Ln of fuel injection valves for injection-supplying fuel to respective cylinders of a diesel engine, and a hold current circuit 34 for supplying a hold current for holding valve opening at the time of current supply, a failure of the boosting circuit 32 is judged from a charging voltage of the capacitor C1, and in the case of failure of the boosting circuit 32, driving time of transistors TR1-TRn for current supply is increased and driving timing is quickened. Consequently, occurrence of engine stalling due to decreased valve opening time or delayed valve opening timing of the fuel injection valve can be prevented even when the peak current can not be supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine which controls a fuel injection amount and a fuel injection timing to an internal combustion engine by controlling an energization time and an energization start timing of an electromagnetic solenoid provided in a fuel injection valve. The present invention relates to a fuel injection control device.

[0002]

2. Description of the Related Art Conventionally, as a fuel injection valve for injecting and supplying fuel to each cylinder of an internal combustion engine, an electromagnetic valve which is normally provided with an electromagnetic solenoid and which is opened by energizing the electromagnetic solenoid has been used. There is.

A drive circuit for driving such a fuel injection valve, as shown in FIG.
a, #b ... Electromagnetic solenoid L of fuel injection valve
The switching transistors TRa, ... And the current limiting ground resistors Rea, respectively provided in the current paths of a, Lb, ... And the corresponding electromagnetic solenoids La, Lb, immediately after the transistors TRa ,. A peak current circuit 5 for promptly opening the fuel injection valve by supplying a predetermined peak current to the diode via the diode Da.
2, and when the transistors TRa, ... Are turned on, a hold current that is smaller than the peak current is supplied to the corresponding electromagnetic solenoids La, Lb, ... Via the diode Db to hold the open state of the fuel injection valve. And a current circuit 54.

That is, the conventional drive circuit for the fuel injection valve is
The peak current circuit 52 including a booster circuit boosts the power supply voltage to generate a high voltage for high-speed valve opening in advance,
When the transistors TRa, ... Are turned on, a high voltage generated thereby causes a large current (peak current) to flow through the electromagnetic solenoids La, Lb, ..., In order to quickly open the fuel injection valve of the corresponding cylinder. A constant current for holding the valve open (hold current) is made to flow from the hold current circuit 54, and the open state of the fuel injection valve of the corresponding cylinder is maintained during the ON period of the transistors TRa.

Further, the fuel injection amount and injection timing from the fuel injection valve driven by such a drive circuit are determined by the energization time and the energization start timing of the electromagnetic solenoid. Therefore, the conventional fuel injection control device calculates the energization time and the energization start timing of the fuel injection valve of each cylinder according to the operating state of the internal combustion engine, and the electromagnetic solenoids La, Lb ... By controlling the pulse width and the output timing of the injection command pulse VCMD output to the transistors TRa provided in series in the current path, respectively, the fuel injection amount and the fuel injection timing from the fuel injection valve to the corresponding cylinder are respectively controlled. It is supposed to be controlled.

That is, according to the drive circuit shown in FIG. 6, as shown in FIG. 7, when the injection command pulse VCMD input to the transistors TRa, rises, the operation of the peak current circuit 52 causes the solenoids La ,. The solenoid current ISOL is held at the hold current until the flowing current (solenoid current ISOL) rapidly rises to the peak current and then the injection command pulse VCMD falls. Therefore, the lift amount SL of the valve body (that is, the opening degree of the fuel injection valve) by the electromagnetic solenoids La, ... Increases gradually after the rise of the injection command pulse VCMD and after the elapse of a predetermined response time t1, and the injection command pulse VCMD After the fall, after a lapse of a predetermined response time t2, it gradually decreases. Depending on the pulse width and output timing of the injection command pulse VCMD, the lift amount SL,
As a result, the fuel injection rate Q is determined. Therefore, in the conventional fuel injection control device, the transistor TR provided in the current path of the electromagnetic solenoids La, Lb ... Of each cylinder.
By controlling the pulse width and output timing of the injection command pulse VCMD output to a, ..., The fuel injection amount and fuel injection timing are controlled for each cylinder of the internal combustion engine.

By the way, in such a conventional drive circuit, when the peak current circuit 52 fails and the peak current cannot be supplied to the electromagnetic solenoids La, ... Immediately after the injection command pulse VCMD rises, as shown in FIG. ,
The response time t1 'from the rise of the injection command pulse VCMD to the opening of the fuel injection valve is the response time t1 in the normal state.
It will be longer. On the other hand, the response time t from the fall of the injection command pulse VCMD until the fuel injection valve is closed
2'is approximately the same as the response time t2 under normal conditions. Therefore, when the peak current circuit fails, both the valve opening time of the fuel injection valve and the fuel injection rate Q become smaller than normal, and the amount of fuel injected into each cylinder of the internal combustion engine becomes smaller than normal.
In some cases, there was a problem such as engine stall.

Therefore, conventionally, in order to solve such a problem, when the peak current cannot be supplied, the hold current is supplied to the electromagnetic solenoid for a longer time to prevent the fuel injection amount from decreasing. It has been considered (JP-A-59-85434).

[0009]

However, when the hold current supply time is increased as described above, the decrease in the fuel injection amount due to the failure of the peak current circuit can be prevented, but the fuel injection valve is opened. Since the valve timing is still delayed from the normal time, the fuel injection timing could not be controlled as in the normal time. Therefore, for an internal combustion engine in which the combustion state of fuel greatly changes depending on the fuel injection timing, such as a diesel engine that performs self-ignition of fuel, when the peak current circuit fails,
There is a problem that it is not possible to execute good fuel injection control using the conventional fuel injection control device, and it becomes impossible to operate the internal combustion engine due to the delay in fuel injection timing.

The present invention has been made in view of these problems, and has an internal combustion engine equipped with a peak current circuit for supplying a large current (peak current) for performing high-speed valve opening to the drive circuit of the fuel injection valve. An object of the present invention is to enable a fuel injection control device for an engine to satisfactorily control the fuel injection amount and the fuel injection timing according to the operating state of the internal combustion engine even when the peak current circuit fails.

[0011]

The invention according to claim 1 made in order to achieve the above object is provided with an electromagnetic solenoid as shown in FIG. 9, and the valve is opened by energizing the electromagnetic solenoid. Fuel injection valve for injecting fuel to an internal combustion engine, a switching element provided in series in a current supply path of the electromagnetic solenoid, and a peak current flowing through the electromagnetic solenoid when the switching element is on A peak current supply means for promptly opening the fuel injection valve and a hold current for supplying a peak current to the fuel injection valve, and then supplying a hold current smaller than the peak current to the electromagnetic solenoid to hold the open state of the fuel injection valve. Depending on the current supply means and the operating state of the internal combustion engine,
A fuel injection control device for an internal combustion engine, comprising: a control unit that calculates an energization time and an energization start timing of the electromagnetic solenoid, and drives and controls the switching element according to the calculation result. Abnormality determining means for determining whether or not the peak current can be supplied to the electromagnetic solenoid; and when the abnormality determining means determines that the peak current supply means cannot supply the peak current to the electromagnetic solenoid, the control means The control amount correction means for increasing the energization time of the electromagnetic solenoid calculated by the above for a predetermined time and correcting the energization start timing of the electromagnetic solenoid to a timing earlier by the predetermined time is provided.

According to a second aspect of the present invention, in the fuel injection control device for the internal combustion engine according to the first aspect, the control amount correcting means increases the energization time of the electromagnetic solenoid and the electromagnetic solenoid. At least one of the correction times for advancing the energization start timing of is set according to the battery voltage received by the hold current supply means such that the lower the battery voltage is, the longer the correction time is,
Is characterized by.

Further, the invention according to claim 3 is the fuel injection control device for an internal combustion engine according to claim 1 or 2, wherein the peak current supply means is parallel to a current supply path of the electromagnetic solenoid. The capacitor provided in
The capacitor comprises a booster circuit that charges the capacitor so that the voltage across the capacitor becomes a high voltage for supplying the peak current, and the abnormality determining means is based on the voltage across the capacitor when the switching element is off, and the peak current supplying means is based on the voltage. Determines whether or not the peak current can be supplied to the electromagnetic solenoid.

[0014]

In the fuel injection control device according to claim 1 configured as described above, the control means sets the energization time and the energization start timing of the electromagnetic solenoid of the fuel injection valve in accordance with the operating state of the internal combustion engine. The switching element, which is calculated and is connected in series to the current supply path of the electromagnetic solenoid, is driven and controlled according to the calculation result. When the switching element is turned on by the control means, first, the peak current supply means supplies the peak current to the electromagnetic solenoid to quickly open the fuel injection valve, and then the hold current supply means causes the electromagnetic solenoid to operate. A hold current is passed to keep the fuel injection valve open.

In the present invention, the abnormality determining means determines whether the peak current supplying means can supply the peak current to the electromagnetic solenoid, and the abnormality determining means causes the peak current supplying means to supply the peak current to the electromagnetic solenoid. If it is determined that the electromagnetic solenoid cannot be supplied, the control amount correction means increases the energization time of the electromagnetic solenoid calculated by the control means for a predetermined time and corrects the energization start timing of the electromagnetic solenoid to be earlier by a predetermined time.

That is, according to the present invention, when the peak current supply means fails and the peak current cannot be supplied to the electromagnetic solenoid, the energization time of the electromagnetic solenoid is lengthened to inject the fuel from the fuel injection valve. It is possible to prevent the amount of fuel from decreasing and to prevent the delay of the start of fuel injection from the fuel injection valve by advancing the start timing of energization of the electromagnetic solenoid.

Next, in the fuel injection control device for the internal combustion engine according to the second aspect, the control amount correction means sets the correction time for increasing the energization time of the electromagnetic solenoid and the correction time for advancing the energization start timing of the electromagnetic solenoid. At least one of them is set so that the lower the battery voltage is, the longer the correction time is, depending on the battery voltage received by the hold current supply means.

That is, when the peak current supply means cannot supply the peak current to the electromagnetic solenoid, only the hold current from the hold current supply means is supplied to the electromagnetic solenoid when the switching element is turned on. The rise of the hold current immediately after turning on becomes slower as the battery voltage is lower. Further, the later the hold current rises, the shorter the valve opening time of the fuel injection valve and the later the valve opening timing. Therefore, in the present invention, at least one of the correction time for increasing the energization time of the electromagnetic solenoid and the correction time for advancing the energization start timing of the electromagnetic solenoid is set to be larger as the battery voltage is lower, so that immediately after the switching element is turned on. The rising characteristic of the hold current prevents the opening time or opening timing of the fuel injection valve from changing.

Next, in the fuel injection control device for the internal combustion engine according to the third aspect, the peak current supply means is provided in parallel with the current supply path of the electromagnetic solenoid by the booster circuit when the switching element is off. The capacitor is charged in advance, and a voltage across the charged capacitor is applied to the electromagnetic solenoid immediately after the switching element is turned on, so that a large current (peak current) flows through the electromagnetic solenoid. Then, the abnormality determination means, when the switching element is off, that is, based on the voltage across the capacitor when the capacitor is charged by the booster circuit,
It is determined whether the peak current supply means can supply the peak current to the electromagnetic solenoid.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. First, Fig. 1 shows each cylinder of a vehicle diesel engine.
Controlling the energization time and the energization timing of the electromagnetic solenoids L1, L2, ... Ln of the n electromagnetic solenoid type unit injectors (hereinafter, simply referred to as injectors) for injecting fuel to 1, # 2, ... #n. The fuel injection control device 1 of the embodiment for controlling the fuel injection amount and the fuel injection timing to each cylinder # 1 to #n of the diesel engine by
It is a block diagram showing the whole 0 structure.

As shown in FIG. 1, the fuel injection control device 10 of this embodiment has a CPU, RO that executes various control processes for fuel injection control according to a preset control program.
Well-known microcomputer 20 including M, RAM, etc.
And a detection circuit 12 for waveform-shaping an output signal from a rotation sensor that generates a rotation signal for each predetermined rotation angle of the diesel engine and inputting it to the microcomputer 20, and an operating state of the diesel engine. The buffers 14 and 16 for inputting the signals from the sensors and switches to the microcomputer 20 and the battery B, respectively.
The voltage of T is divided and input to the microcomputer 20. The battery voltage detection circuit 18 composed of voltage dividing resistors RS1 and RS2 and the electromagnetic solenoids L1 to Ln are energized to drive the injectors of the cylinders # 1 to #n. Interface 2 that receives control signals from the drive circuit 30 and the microcomputer 20 and outputs an injection command pulse to the drive circuit 30.
2 and a power supply circuit 26 which receives power supply from the battery BT and supplies a predetermined power supply voltage (constant voltage) to each of the above-mentioned parts.

The drive circuit 30 receives each injection command pulse from the interface 22 and outputs the injection command pulse to each cylinder # 1.
A switching circuit 36 that connects and disconnects the current paths of the electromagnetic solenoids L1 to Ln of #n to #n, respectively.
Predetermined hold current (constant current) via diode D2
For supplying peak current, a capacitor C1 for supplying peak current, which is provided in parallel with electromagnetic solenoids L1 to Ln of each cylinder # 1 to #n via a diode D1, and a high voltage to the capacitor C1 when the switching circuit 36 is off. A peak current supply for charging a voltage and supplying a peak current to the corresponding electromagnetic solenoid L by the high voltage charged in the capacitor C1 when the current path of one of the electromagnetic solenoids L is made conductive by the switching circuit 36. The voltage across the capacitor C1 is detected by the booster circuit 32 and the voltage dividing resistors R1 and R2 as means, and the detected voltage is
It is determined whether the output voltage (constant voltage) from the power supply circuit 26 is divided by the voltage dividing resistors R3 and R4 or more,
A comparator COM that outputs the determination result to the microcomputer 20 is provided.

Here, the booster circuit 32 includes a booster transformer Lo to which a battery voltage is applied to one end of a primary winding, and a drive pulse of a high frequency (about several tens kHz in this embodiment) input from the outside. By switching at high speed with, the other end of the primary winding of the transformer Lo is grounded at high frequency,
A boosting transistor TRo that generates a high voltage in the secondary winding of the transformer Lo and a diode Do that charges the capacitor C1 by outputting the high voltage generated in the secondary winding of the transformer Lo to the capacitor C1. It is a well-known one configured by and, by an operation command from the microcomputer 20 input through the interface 22,
It operates during the off period of the electromagnetic solenoids L1 to Ln.

The hold current circuit 34 is a constant current circuit that receives a power supply from the battery BT and supplies a hold voltage for maintaining the injector valve open to the electromagnetic solenoid L whose current path is conductive. Control for turning on / off the switching element so that the voltage across the current detecting resistor, the switching element for connecting / disconnecting the current path, and the current detecting resistor provided in series in the current path of the solenoid L become a predetermined voltage. It is a well-known one including a circuit and the like.

On the other hand, the switching circuit 36 is provided for each cylinder #
Switching transistors TR provided in series in the current paths of the electromagnetic solenoids L1 to Ln of 1 to #n, respectively.
1, TR2, ... TRn and these transistors TR1
Ground terminals of TRn (transistor T in this embodiment)
Since an NPN transistor is used for R1 to TRn, it serves as an emitter terminal.) A grounding resistor Reo connected to
, And input resistors Ra1, Ra2, ... Ran for inputting the injection command pulse for each cylinder input from the interface 22 to the bases of the corresponding transistors TR1 to TRn.
It consists of and.

In the drive circuit 30 thus constructed, as shown in FIG. 2, the injection command pulse V for each cylinder is inputted from the interface 22 to the switching circuit 36.
When all the CMDs are in the off state, the capacitor C1 for supplying the peak current has a predetermined upper limit voltage (120 in this embodiment).
V) is charged. Then, when the injection command pulse VCMD is input from the interface 22 to energize the electromagnetic solenoid L of one of the cylinders and the transistor TR of the corresponding cylinder is turned on, the voltage charged in the capacitor C1 causes the electromagnetic solenoid L to flow. A discharge is made within a predetermined discharge time TDCHG, and a peak current flows through the electromagnetic solenoid L. Then, after that, the hold current flows through the electromagnetic solenoid L by the operation of the hold current circuit 34,
When the input of the injection command pulse VCMD from the interface 22 is stopped, the electromagnetic solenoid L is de-energized. Further, when the energization of the electromagnetic solenoid L is cut off in this way, the operation of the booster circuit 32 causes a predetermined charging time T.
The capacitor C1 is charged to the upper limit voltage in CHG, and the peak current can be supplied when the injection command pulse VCMD is input next.

The comparator COM includes a detection voltage obtained by the voltage dividing resistors R1 and R2 and a voltage dividing resistor R.
By comparing with the reference voltage obtained by 3 and R4, it is determined whether the voltage across the capacitor C1 charged by the booster circuit 32 is, for example, 60 V or more, which is a half of the upper limit voltage 120 V in the normal state. If it is 60 V or more, a high level signal is generated, and if it is less than 60 V, a low level signal is generated.

Next, the fuel injection control process executed by the microcomputer 20 will be described with reference to the flow chart shown in FIG. The fuel injection control process is repeatedly executed by the microcomputer 20 after the diesel engine is started.

As shown in FIG. 3, when the fuel injection control process is started, first, at step 110, various detection signals input from the detection circuit 12, the buffer 14 and the buffer 16 and representing the operating state of the diesel engine are read. . Then, in the following step 120, the injection pulse width TAU representing the energization time of the electromagnetic solenoid L is calculated based on the read detection signal, and in the next step 130, the injection timing representing the energization start timing of the electromagnetic solenoid L. Calculate Ts.

Next, in step 140, after the interface 22 has stopped outputting the injection command pulse VCMD, the input signal (determination signal) from the comparator COM after the elapse of the predetermined charging time TCHG shown in FIG. 2 becomes High. A process as an abnormality determining unit that determines whether the charging voltage of the capacitor C1 is a voltage that can supply the peak current to the electromagnetic solenoid L depending on whether the level is the level or not is executed.

When it is determined in step 140 that the determination signal from the comparator COM is at the high level, the booster circuit 32 is operating normally, and the peak current is supplied by the voltage charged in the capacitor C1. If it is determined that the operation is possible, the process directly proceeds to step 200, and the interface 22 is displayed on the steps 120 and 13 described above.
The injection command is set by outputting a control signal representing the injection pulse width TAU calculated at 0 and the injection timing Ts.

On the other hand, when it is determined in step 140 that the determination signal from the comparator COM is at the low level, the booster circuit 32 is not operating normally and the peak current is supplied from the capacitor C1 to the electromagnetic solenoid L. When it is determined that the battery voltage cannot be obtained, the process proceeds to step 150, and the battery voltage detected by the battery voltage detection circuit 18 is read.

Then, in the following step 160, based on the read battery voltage, a correction amount ΔTQ for correcting the injection pulse width, which becomes larger as the battery voltage becomes lower, is calculated using the map shown in FIG. Step 170
Then, based on the read battery voltage, a correction amount ΔTs for injection timing correction that increases as the battery voltage decreases is calculated using a map (not shown). The map for calculating the correction amount ΔTs has substantially the same characteristics as the map for calculating the correction amount ΔTQ for correcting the injection pulse width shown in FIG.

Further, when the correction amounts ΔTQ and ΔTs are calculated in steps 160 and 170 in this way, this time, in step 180, the correction amount ΔTQ is calculated in step 120. By adding to the width TAU, the injection pulse width TAU, in other words, the energization time of the electromagnetic solenoid, is lengthened, and in step 190, the injection timing Ts calculated in step 130 is advanced by the correction amount ΔTs. Then, the timing of starting energization of the electromagnetic solenoid is advanced, and the process proceeds to step 200.

Incidentally, the above steps 150 to 19
The process of 0 corresponds to the control amount correction means. in this way,
In this embodiment, the abnormality of the booster circuit 32 constituting the peak current supply means is determined from the charging voltage of the capacitor C1, and when the booster circuit 32 is abnormal, it is calculated according to the operating state of the diesel engine as shown in FIG. The injection pulse width TAU shown by the dotted line is lengthened by the correction amount ΔTQ as shown by the solid line, and the injection timing Ts is advanced by the correction amount ΔTs.

Therefore, even if the booster circuit 32 fails and the hold current circuit 34 alone can supply the current to the electromagnetic solenoids L1 to Ln, the solenoid currents to the electromagnetic solenoids L1 to Ln can be supplied. It is possible to prevent the decrease of the fuel injection amount from the injector by increasing the energization time of ISOL, and to prevent the delay of the fuel injection start timing by advancing the valve opening timing of the injector.

Therefore, according to this embodiment, when the injection pulse width TAU and the injection timing Ts are not corrected (FIG. 5).
(Indicated by a dotted line), it is possible to prevent the injector valve opening time and the fuel injection rate Q from decreasing, or delay the start of fuel injection, and to operate the diesel engine even when the booster circuit 32 fails. Will be able to. In this way, even when the booster circuit 32 fails,
Since the diesel engine can be driven, it is possible to improve the safety when the vehicle equipped with such a diesel engine is running.

Further, in this embodiment, the injection pulse width TAU is
The correction amount ΔTQ and the correction amount ΔTs of the injection timing Ts are set so that the correction amount increases as the battery voltage decreases, depending on the battery voltage. Therefore, it is possible to prevent the valve opening timing of the injector from being delayed or the valve opening time being shortened when the battery voltage is low.

That is, when the booster circuit 32 is operating normally, the capacitor C
1 is charged with the upper limit voltage, so that the peak current can be supplied when the energization of the electromagnetic solenoids L1 to Ln is started, and the valve opening timing of the injector does not fluctuate due to the battery voltage, but the booster circuit 32 fails. Therefore, when only the hold current from the hold current circuit 34 can be supplied to the electromagnetic solenoids L1 to Ln, the electromagnetic solenoids L1 to Ln are driven by the battery voltage. Therefore, when the battery voltage is reduced, the valve opening timing of the injector is decreased. I'll be late. However, in the present embodiment, as described above, the correction amount ΔTQ of the injection pulse width TAU and the injection timing T
Since the correction amount ΔTs of s is set according to the battery voltage, it is possible to prevent the fuel injection amount and the injection timing from varying due to the battery voltage, and to execute the fuel injection control better. Will be able to.

Furthermore, in this embodiment, the abnormality of the booster circuit 32 as the peak current supply means is detected by the comparator CO.
Since M is used to determine from the charging voltage of the capacitor C1 charged by the booster circuit 32, it is possible to quickly determine the abnormality of the booster circuit 32. That is, the abnormality of the booster circuit 32 is caused by the electromagnetic solenoids L1 to Ln.
It is possible to make a determination by monitoring the peak current actually flowing in the injection pulse width TAU. In this case, since the booster circuit 32 is determined to be abnormal after the peak current cannot be supplied to the electromagnetic solenoids L1 to Ln. The correction of the injection timing Ts may be delayed and the engine may stall in some cases. However, in this embodiment, it is possible to determine the abnormality of the booster circuit 32 before energization of the electromagnetic solenoids L1 to Ln. It is possible to make the determination, and further, the injection pulse width TAU and the injection timing Ts can be corrected earlier, which also makes it possible to prevent the engine stall more reliably.

In this embodiment, the injection pulse width TAU is
The correction amount ΔTQ and the correction amount ΔTs of the injection timing Ts are set in accordance with the battery voltage.
Further, by monitoring the charging voltage of the capacitor C1 and correcting the correction amounts ΔTQ and ΔTs so that the higher the charging voltage is, the smaller the correction amounts ΔTQ and ΔTs are. The fuel injection control can be executed with higher accuracy.

[0042]

As described above in detail, in the fuel injection control device according to the first aspect of the present invention, when the peak current supply means fails and the peak current cannot be supplied to the electromagnetic solenoid, Increase the energization time of the solenoid,
Moreover, the timing of starting energization of the electromagnetic solenoid is set to be advanced. Therefore, according to the present invention, even if the peak current supply means fails and only the hold current can be supplied to the electromagnetic solenoid, the fuel injection amount from the fuel injection valve is prevented from decreasing. And moreover,
It is possible to prevent the start of fuel injection from the fuel injection valve from being delayed. Therefore, according to the present invention, even in an internal combustion engine such as a diesel engine in which the combustion state of fuel greatly changes depending on the fuel injection timing, it is possible to perform the operation when the peak current supply means fails. become.

In the fuel injection control device for the internal combustion engine according to the second aspect, the battery voltage is low for at least one of the correction time for increasing the energization time of the electromagnetic solenoid and the correction time for advancing the energization start timing of the electromagnetic solenoid. Since the setting is made so as to be moderately large, it is possible to prevent the valve opening time or the valve opening timing of the fuel injection valve from changing depending on the magnitude of the battery voltage. Therefore, the operation of the internal combustion engine can be executed more reliably.

Further, in the fuel injection control device for the internal combustion engine according to the third aspect, whether or not the peak current can be supplied to the electromagnetic solenoid is determined based on the voltage across the capacitor charged by the peak current supply means. Has been Therefore, according to the present invention, the abnormality determination of the peak current supply means, and further the correction of the energization time and the energization start timing of the electromagnetic solenoid can be executed without a response delay, and the engine stall due to the failure of the peak current supply means can be performed. It can be prevented more reliably.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an overall configuration of a fuel injection control device of an embodiment.

FIG. 2 is an explanatory diagram illustrating changes in a terminal voltage and a solenoid current of a capacitor for supplying a peak current according to an embodiment.

FIG. 3 is a flowchart showing a fuel injection control process executed by the microcomputer of the embodiment.

FIG. 4 is an explanatory diagram illustrating a map used when calculating a correction amount ΔTQ for correcting an injection pulse width in the fuel injection control process of the embodiment.

FIG. 5 is an operation explanatory diagram illustrating an operation of fuel injection control when the booster circuit of the embodiment fails.

FIG. 6 is a schematic configuration diagram showing a configuration of a conventional fuel injection valve drive circuit.

FIG. 7 is an operation explanatory view illustrating an operation of fuel injection control when the fuel injection valve drive circuit is normal.

FIG. 8 is an operation explanatory diagram illustrating an operation of fuel injection control when correction is not performed when a peak current circuit (step-up circuit) fails.

FIG. 9 is a block diagram illustrating the configuration of the present invention.

[Explanation of symbols]

10 ... Fuel injection control device 18 ... Battery voltage detection circuit 20 ... Microcomputer 30 ... Drive circuit 3
2 ... Booster circuit 34 ... Hold current circuit 36 ... Switching circuit
BT ... Battery C1 ... Capacitor COM ... Comparator L1
Ln ... Electromagnetic solenoid

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location F02D 41/22 380 HM 385 HM

Claims (3)

[Claims] 1. A fuel injection valve comprising an electromagnetic solenoid, which is opened by energizing the electromagnetic solenoid to inject fuel into an internal combustion engine, and a switching element provided in series in a current supply path of the electromagnetic solenoid. A peak current supply means for causing a peak current to flow through the electromagnetic solenoid when the switching element is turned on to quickly open the fuel injection valve; and after supplying the peak current to the fuel injection valve, the electromagnetic solenoid Hold current supply means for holding a valve open state of the fuel injection valve by flowing a hold current smaller than a peak current, and calculating an energization time and an energization start timing of the electromagnetic solenoid according to the operating state of the internal combustion engine, A fuel injection control device for an internal combustion engine, comprising: a control unit that drives and controls the switching element according to the calculation result. And an abnormality determining means for determining whether or not the peak current supplying means can supply the peak current to the electromagnetic solenoid, and the abnormality determining means means that the peak current supplying means cannot supply the peak current to the electromagnetic solenoid. When it is judged, the control amount correction means for increasing the energization time of the electromagnetic solenoid calculated by the control means for a predetermined time and correcting the energization start timing of the electromagnetic solenoid to be earlier by a predetermined time is provided. A fuel injection control device for an internal combustion engine, comprising: 2. The battery voltage received by the hold current supply means includes at least one of a correction time for increasing the energization time of the electromagnetic solenoid and a correction time for advancing the energization start timing of the electromagnetic solenoid by the control amount correction means. Accordingly, the fuel injection control device for the internal combustion engine according to claim 1, wherein the correction time is set to increase as the battery voltage decreases. 3. The peak current supply means comprises a booster circuit for charging a capacitor provided in parallel with the current supply path of the electromagnetic solenoid so that the voltage across the capacitor becomes a high voltage for peak current supply. The abnormality determination means determines whether or not the peak current supply means can supply a peak current to the electromagnetic solenoid based on the voltage across the capacitor when the switching element is off. A fuel injection control device for an internal combustion engine according to claim 1 or 2.