JPH1113519A - Diagnostic device for drive control device of fuel injection valve, and diagnostic device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diagnostic device capable of diagnosing highly precisely a drive control device of a fuel injection valve, and highly precisely diagnose the diagnostic device itself. SOLUTION: When a valve opening current does not reach a determination value 1 in a valve opening current diagnosing window, a failure diagnosing circuit diagnoses the existence of abnormality in a drive control device. When a holding current comes to a determination value 4 or more, or a determination value 5 or less in a holding current diagnosing window, the failure diagnosing circuit diagnoses the existence of abnormality in the drive control device. After a power source of solenoid is turned off, the drive control device and a control unit are operated during a prescribed time to transmit a injection signal for disgnosis to the drive control device. At that time, the drive control device is diagnosed to be normal if the failure diagnosing circuit 8 is normal. When the failure diagnosing device diagnoses the normality of the drive control device, the failure diagnosing circuit is diagnosed to be abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diagnostic device for a drive control device for an electromagnetic (solenoid) fuel injection valve and a diagnostic device for the diagnostic device.

[0002]

2. Description of the Related Art A conventional drive control apparatus for an electromagnetic fuel injection valve used in an internal combustion engine is disclosed, for example, in Japanese Patent Application Laid-Open No.
There is one as disclosed in JP-A-01552. Such a conventional fuel injection valve drive control device provides a relatively large drive current (valve opening current) to a drive solenoid provided in the fuel injection valve by using a battery power supply and a booster circuit in an early stage of valve opening, and has a responsiveness. While opening the valve well,
Thereafter, when the current value of the drive current becomes equal to or more than a predetermined value, a relatively small drive current (holding current) capable of maintaining the valve open state is provided via a battery power supply, and the current value is maintained for a predetermined valve open time, A desired fuel injection amount can be achieved.

[0003]

However, the above-described conventional fuel injection valve drive control device does not include a self-diagnosis device, and diagnoses whether the drive control device is operating normally. I couldn't do that. for that reason,
There is a concern that the user or the like may be delayed in recognizing the operation failure or the like, and delay in measures for various situations (for example, deterioration in driving performance, fuel consumption, exhaust performance, etc.) caused by the operation failure or the like.

[0004] When a self-diagnosis device is provided, it is desirable to be able to diagnose whether or not the self-diagnosis device is functioning normally from the viewpoint of preventing erroneous diagnosis. is there. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a fuel injection valve drive control device diagnostic device that can diagnose a fuel injection valve drive control device with high accuracy with a simple and low-cost configuration. And Another object of the present invention is to enable the diagnosis of the diagnostic device itself to be performed with high accuracy with a simple and low-cost configuration.

[0005]

Therefore, according to the first aspect of the present invention, as shown by the solid line in FIG. 1, the fuel injection valve starts to operate when the fuel injection start command is input from the engine control unit. While providing a valve-opening current to a relatively large predetermined value to the provided solenoid to open the fuel injection valve, after the valve-opening current reaches the predetermined value, a relatively small valve that can maintain the valve-open state can be maintained. A diagnostic device for a drive control device for a fuel injection valve configured to supply a holding current to a solenoid and maintain the holding current value until a fuel injection stop command is input from an engine control unit. Current value detecting means for detecting a current value being supplied, and a current in a normal state from when the fuel injection start command is input until the valve opening current reaches the predetermined value. Valve opening current diagnosing means for diagnosing the presence or absence of a failure related to the valve opening current of the drive control device for the fuel injection valve based on the characteristic and the current value characteristic actually detected by the current value detecting means. , Is included.

With this configuration, the current value characteristic in a normal state from the time when the fuel injection start command is input to the time when the valve opening current reaches the predetermined value, and the current value characteristic actually detected by the current value detecting means. By comparing the current value characteristic with the current value characteristic, it is possible to easily and accurately diagnose whether there is a failure (abnormality) related to the valve opening current of the drive control device for the fuel injection valve.

According to the second aspect of the present invention, as shown by the solid line in FIG. 2, when a fuel injection start command is input from the engine control unit, a relatively large predetermined value is applied to the solenoid of the fuel injection valve. The valve opening current is applied to open the fuel injection valve, and after the valve opening current reaches a predetermined value, a relatively small holding current capable of maintaining the valve open state is applied to the solenoid to control the engine. A diagnostic device for a drive control device for a fuel injection valve configured to maintain a holding current value until a fuel injection stop command is input from a unit, wherein a current for detecting a current value applied to the solenoid is provided. Value detection means, a holding current value maintained until a fuel injection stop command is input in a normal state, and a current value actually detected by the current value detection means, Based on, and to be configured to include a holding current diagnostic means for diagnosing the presence or absence of a failure associated with the holding current of the drive control device of the fuel injection valve.

[0010] According to this configuration, the holding current value maintained until the fuel injection stop command is input in the normal state is compared with the current value actually detected by the current value detecting means. It is possible to easily and accurately diagnose whether there is a failure (abnormality) related to the holding current of the drive control device for the fuel injection valve. According to the third aspect of the present invention, as shown by the solid line in FIG. 3, the solenoid is opened from when the fuel injection start command is input from the engine control unit to when the solenoid of the fuel injection valve reaches a relatively large predetermined value. While giving the valve current to open the fuel injection valve, after the valve opening current reaches a predetermined value, a relatively small holding current capable of holding the valve open state is given to the solenoid, and the engine control unit sends What is claimed is: 1. A diagnostic device for a drive control device for a fuel injection valve, wherein a holding current value is maintained until a fuel injection stop command is input, wherein a current value detecting means detects a current value given to the solenoid. A current value characteristic in a normal state from the time when the fuel injection start command is input to the time when the valve opening current reaches the predetermined value; Based on the detected current value characteristic, a valve opening current diagnosing means for diagnosing the presence or absence of a failure related to the valve opening current of the drive control device for the fuel injection valve, and a fuel injection stop command in a normal state is input. A diagnosis for determining whether there is a failure related to the holding current of the drive control device of the fuel injection valve based on the holding current value maintained until the current value and the current value actually detected by the current value detecting means. And a current diagnostic means.

With this configuration, the current value characteristic in a normal state from when the fuel injection start command is input to when the valve opening current reaches the predetermined value, and the current value characteristic actually detected by the current value detecting means. By comparing the current value characteristic with the current value characteristic, it is possible to easily and accurately diagnose whether there is a failure (abnormality) related to the valve opening current of the drive control device of the fuel injection valve, and to determine whether the fuel is normal. By comparing the holding current value maintained until the injection stop command is input with the current value actually detected by the current value detecting means, the drive control device for the fuel injection valve can be easily and accurately adjusted. It is possible to diagnose the presence or absence of a failure (abnormality) related to the holding current.

That is, according to this configuration, if any of the failures related to the valve opening current or the failure related to the holding current occurs in the drive control device for the fuel injection valve, the failure is immediately diagnosed, so that the fuel injection valve is quickly diagnosed. Diagnostics, and
It is also possible to specify a failure (abnormal) location. Therefore, the driver or the like can be quickly made aware of the failure (abnormality), and quick action can be taken for the failure (abnormality).

According to a fourth aspect of the present invention, there is provided a diagnostic device for a drive control device for a fuel injection valve, wherein the solenoid is disconnected from a power source as shown by a broken line in FIG. For a predetermined period, a first function maintaining means for maintaining the functions of the engine control unit, the drive control device for the fuel injection valve, the valve opening current diagnostic means and the current value detecting means, the solenoid, and a power supply. After disconnection, diagnostic injection command generating means for generating a diagnostic injection start command and a diagnostic injection stop command at predetermined intervals in the control unit whose function is maintained,
After the solenoid and the power supply are disconnected, when the diagnostic injection start command is input to the drive control device for the fuel injection valve, the valve-opening current diagnostic means controls the drive of the fuel injection valve. When it is diagnosed that there is no failure related to the valve opening current of the control device, the valve opening current diagnosing means includes a first failure diagnosing means for diagnosing failure.

That is, when a diagnostic injection start command is forcibly generated and given to the drive control device under the condition that the valve opening current cannot flow through the solenoid, the diagnosis is performed by detecting the valve opening current characteristic. The valve opening current diagnostic means should diagnose that the drive control device has a failure (abnormality). On the other hand, if it is diagnosed that the drive control device is normal, the valve opening current diagnostic means has a failure (abnormality). Can be diagnosed.

Therefore, according to the above configuration, it is possible to easily and accurately diagnose the failure of the diagnostic device of the drive control device for the fuel injection valve. In the above configuration, the diagnostic device for the drive control device for the fuel injection valve and the diagnostic device for the diagnostic device for the drive control device for the fuel injection valve are provided under the condition for performing the diagnosis (under the condition that the valve opening current flows through the solenoid). Or a condition under which the flow cannot flow), and the diagnosis is performed using the common valve opening current diagnosis means. It is not necessary to add a new diagnostic means (diagnosis circuit etc.) separately,
The configuration can be simplified and the cost can be reduced.

According to a fifth aspect of the present invention, in the diagnostic device for a drive control device for a fuel injection valve, as shown by a broken line in FIG. 2, the solenoid is disconnected from a power supply. Connection between the engine control unit, the drive control device for the fuel injector, the holding current diagnostic unit, the second function maintaining unit for maintaining the functions of the current value detecting unit, the solenoid, and a power supply for a predetermined period from After the disconnection, diagnostic injection command generating means for generating a diagnostic injection start command and a diagnostic injection stop command at predetermined intervals in the control unit whose function is maintained,
After the disconnection of the solenoid and the power supply, when the diagnostic injection start command is input to the drive control device of the fuel injection valve, the holding current diagnostic means controls the drive of the fuel injection valve. When it is diagnosed that there is no failure related to the holding current of the device, a second failure diagnosis means for diagnosing that the holding current diagnosis means has failed is provided.

That is, when a diagnostic injection start command is forcibly generated and given to the drive control device under the condition that the holding current cannot flow through the solenoid, the holding current for detecting the holding current characteristic and performing diagnosis is provided. The diagnostic means should diagnose that the drive control device has a failure (abnormality). On the other hand, if it is determined that the drive control device is normal, it is determined that the holding current diagnostic means has a failure (abnormality). Can be.

Therefore, according to the above configuration, it is possible to easily and accurately diagnose the failure of the diagnostic device of the fuel injection valve drive control device. In the above configuration, the diagnostic device for the drive control device for the fuel injection valve and the diagnostic device for the diagnostic device for the drive control device for the fuel injection valve are provided under the condition for performing the diagnosis (under the condition that the holding current flows through the solenoid. Or the condition under which the flow cannot flow), and the diagnosis is performed using the common holding current diagnosis means. Since it is not necessary to add a new means (diagnosis circuit, etc.) separately,
The configuration can be simplified and the cost can be reduced.

In the diagnostic device of the fuel injection valve drive control device according to the present invention, the solenoid and the power supply are disconnected as shown by a broken line in FIG. A third function maintaining means for maintaining the functions of the engine control unit, the drive control device for the fuel injection valve, the valve opening current diagnostic means, the holding current diagnostic means, and the current value detecting means for a predetermined period of time; A diagnostic injection command generating means for generating a diagnostic injection start command and a diagnostic injection stop command at predetermined intervals in the control unit whose functions are maintained after the connection to the power supply is disconnected; After disconnection of the solenoid and the power supply, when the diagnostic injection start command is input to the drive control device of the fuel injection valve, the valve opening current diagnostic means or the When the holding current diagnosis unit diagnoses that there is no failure related to the valve opening current or the holding current of the drive control device of the fuel injection valve, the valve opening current diagnosis unit or the holding current diagnosis unit has failed. The third to diagnose
And failure diagnosis means.

That is, when a diagnostic injection start command is forcibly generated and given to the drive control device under the condition that the valve opening current or the holding current cannot flow through the solenoid, the valve opening current characteristic is detected. The valve opening current diagnosing means for diagnosing and the holding current diagnosing means for diagnosing by detecting the holding current characteristic should diagnose that the drive control device has a failure (abnormality). When it is diagnosed that there is, it can be diagnosed that there is a failure (abnormality) in the valve opening current diagnosing means or the holding current diagnosing means.

Therefore, according to the above configuration, it is possible to easily and accurately diagnose the failure of the diagnostic device of the fuel injection valve drive control device. In the above configuration, the diagnostic device for the drive control device for the fuel injection valve and the diagnostic device for the diagnostic device for the drive control device for the fuel injection valve are provided under the condition for performing the diagnosis (under the condition that the holding current flows through the solenoid. Or the condition under which the flow cannot flow), and the diagnosis is performed using the common valve opening current diagnosis means and the holding current diagnosis means. Since it is not necessary to separately add a new diagnostic means (diagnostic circuit or the like) for the diagnostic device, it is possible to simplify the configuration and reduce the cost.

Further, according to the above configuration, if any one of the valve-opening current diagnosing means and the holding current diagnosing means is diagnosed with a failure, the failure is immediately diagnosed, so that a quick diagnosis can be performed. It is also possible to specify a failure (abnormal) location. Therefore, the driver or the like can be quickly made aware of the failure (abnormality), and quick action can be taken for the failure (abnormality).

In the invention described in claim 7, the predetermined interval is set to an interval at which the holding current diagnostic means can function sufficiently. With this configuration, for example, the predetermined interval is prevented from being set short, so that the holding current diagnostic unit that detects the holding current characteristic and performs diagnosis can reliably avoid the possibility of erroneous diagnosis. can do. That is, for example, if the predetermined interval is set to be short, there is a possibility that the holding current diagnosis unit may perform a failure diagnosis based on a current value or the like during the transition from the valve opening current to the holding current, and an erroneous diagnosis is performed. Although the fear increases, such a fear can be reliably avoided with the above configuration.

[0022]

According to the first aspect of the present invention, the current value characteristic in a normal state from when the fuel injection start command is input to when the valve opening current reaches the predetermined value, By comparing the current value characteristic detected by the current value detection means with the current value characteristic, it is possible to easily and accurately diagnose whether there is a failure (abnormality) related to the valve opening current of the drive control device for the fuel injection valve. it can.

According to the second aspect of the present invention, the holding current value maintained until the fuel injection stop command is input in the normal state and the current value actually detected by the current value detecting means are determined. By performing the comparison, it is possible to easily and accurately diagnose whether there is a failure (abnormality) related to the holding current of the drive control device for the fuel injection valve. According to the third aspect of the present invention, the current value characteristic in a normal state from the time when the fuel injection start command is input to the time when the valve opening current reaches the predetermined value, and the current value actually detected by the current value detecting means. By comparing the detected current value characteristic with the detected current value characteristic, it is possible to easily and accurately diagnose whether there is a failure (abnormality) related to the valve opening current of the fuel injection valve drive control device,
By comparing a holding current value maintained until a fuel injection stop command is input in a normal state with a current value actually detected by the current value detecting means, the fuel injection valve can be easily and accurately adjusted. It is possible to diagnose whether there is a failure (abnormality) related to the holding current of the drive control device.

Further, if a failure related to the valve opening current or a failure related to the holding current occurs in the drive control device for the fuel injection valve, the failure is immediately diagnosed, so that a quick diagnosis can be performed. In addition to this, it is also possible to specify a failure (abnormal) location. Therefore, the driver or the like can be quickly made aware of the failure (abnormality), and quick action can be taken for the failure (abnormality).

According to the fourth and fifth aspects of the present invention, the failure diagnosis of the diagnostic device of the drive control device for the fuel injection valve is performed with high accuracy while simplifying the configuration and reducing the cost. be able to. According to the sixth aspect of the present invention, in addition to the functions and effects of the fourth and fifth aspects of the present invention, it is further diagnosed that one of the valve opening current diagnosing means and the holding current diagnosing means is faulty. If this is done, it is immediately diagnosed that the diagnostic device of the drive control device for the fuel injection valve is faulty, so that a quick diagnosis can be performed and a faulty (abnormal) location can be specified. Therefore, the driver or the like can be quickly made aware of the failure (abnormality), and quick action can be taken for the failure (abnormality).

According to the seventh aspect of the present invention, the predetermined interval is set to an interval at which the holding current diagnosing means can function sufficiently, so that the holding current diagnosing means for detecting the holding current characteristic and performing diagnosis is provided. The possibility of erroneous diagnosis can be reliably avoided.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 4, a drive control device (injector drive [drive] unit) 1 for a solenoid type fuel injection valve (injector) according to an embodiment of the present invention operates in an engine control unit 2 (intake air flow rate, Receiving an injection signal (injection pulse signal) set based on the engine rotation speed, water temperature, target air-fuel ratio, etc., and controlling the first transistor (Tr1) and the second transistor (Tr2) based on the injection signal to make the injector A control circuit 3 for controlling a drive current to a solenoid (fuel injection valve) 4 is provided.

The control circuit 3 is connected to a base terminal B1 of the first transistor (Tr1) and a base terminal (switching element) B2 of the second transistor (Tr2). A switching signal is supplied to the switching element B2 to turn on and off the first transistor Tr1 and the second transistor Tr2.
FF control is performed to control a drive current supplied from the battery voltage 5 and the booster circuit 6 to the injector solenoid 4.

More specifically, for example, as shown in the timing chart of FIG. 5, in the early stage of valve opening (immediately after the injection signal is turned on), both the first transistor (Tr1) and the second transistor (Tr2) are connected. When turned on, a large drive current (injector current; valve opening current) is applied to the injector solenoid 4 to increase the responsiveness of the valve opening operation. Thereafter, when the drive current (injector current; valve opening current) becomes equal to or more than a predetermined value, only the first transistor (Tr1) is turned off.
The valve opening current (the current from the booster circuit 6) is supplied to the injector solenoid 4 only by the second transistor (Tr2).
To maintain the responsiveness and stability of the valve opening operation.

Further, when the drive current (injector current) exceeds the determination value 1 after a lapse of time, the second transistor (Tr2) is turned off. After that, the first transistor (Tr1) is ON / OFF controlled so that the drive current is maintained between the judgment value 2 and the judgment value 3 (holding current for holding the valve open state). Then, the fuel injection valve (injector solenoid 4) is closed at the timing when the injection signal set based on the operation state or the like in the engine control unit 2 is turned off. Time (fuel injection amount) is to be achieved.

In order to control the driving of the fuel injection valve (injector solenoid) 4, the injector drive unit (injector drive control device) 1 according to the present embodiment is provided with a current detection circuit 7. . The current detection circuit 7 includes a current detection unit 1 for detecting that the injector drive current has reached the determination value 1,
It comprises current detecting means 2 for detecting that the injector drive current has reached the determination value 2, and current detection means 3 for detecting that the injector drive current has reached the determination value 3.

The injector drive unit 1 according to the present embodiment has a failure diagnosis circuit 8 for diagnosing whether or not the above control (control shown in the timing chart of FIG. 5) by the injector drive unit 1 is normally performed. Is provided. The failure diagnosis circuit 8 functions as a valve opening current diagnosis unit and a holding current diagnosis unit according to the present invention, as described later.

Here, the failure diagnosis control of the injector drive unit 1 performed by the failure diagnosis circuit 8 according to the present embodiment will be described. In the failure diagnosis circuit 8 according to the present embodiment, as shown in the timing chart of FIG.
i.

If it is normal (see the state shown by the broken line in FIG. 6), the valve-opening current diagnosis window is opened for a period sufficient for the drive current to reach the judgment value 1 after the injection signal is turned on. Hi is maintained. Therefore, if the drive current does not reach the determination value 1 during the Hi period of the valve opening current diagnosis window (see FIG. 6).
In this case, it is possible to diagnose that the drive control device or the like is not functioning properly.

Further, the failure diagnosis circuit 8 according to the present embodiment
As shown in FIG. 6, a holding current diagnostic window is provided which becomes Hi after a predetermined period elapses after the injection signal is turned ON and becomes Lo after a predetermined period elapses after becoming Hi. . That is, if the drive current is normal, the holding current diagnostic window is set to Hi in accordance with the timing and period when the drive current will be maintained between the determination value 2 and the determination value 3 (desired holding current). Controlled.

Therefore, for example, when the drive current becomes higher than a predetermined value (for example, 4 or more) or lower than a predetermined value (for example, 5 or less) while the holding current diagnosis window is set to Hi. In this case, it can be diagnosed that the holding current is not maintained satisfactorily and that there is some abnormality in the drive control device or the like. The holding current diagnosis window is set to Hi after a predetermined period has elapsed since the injection signal was turned ON, only after the valve-opening current given in the early stage of valve-opening has decreased to a value smaller than the determination value 4. This is because the failure diagnosis method cannot accurately determine whether the holding current is normally applied.

In the failure diagnosis circuit 8 according to the present embodiment, for example, when it is determined that there is an abnormality in either the valve opening current window or the holding current window, the diagnosis signal is set to Hi. While maintaining it, only when it is diagnosed as normal in any window,
When the injection signal is temporarily turned off, the diagnostic signal is set to Lo (the Lo signal is output only for one shot).
It has become.

This diagnostic signal is input to the engine control unit 2 as shown in FIG. 4, and when the diagnostic signal remains Hi, the engine drive unit 1 sends some abnormality to the injector drive unit 1. When there is a warning, a warning light or the like is turned on or blinked, so that the driver or the like recognizes that there is some abnormality, and prompts a measure or the like.

For the purpose of such fault diagnosis control, the current detection circuit 7 includes, in addition to the current detection means 1 to 3, a current detection means 4 for detecting that the injector drive current has reached the determination value 4. And a current detecting means 5 for detecting that the injector drive current has reached the determination value 5. The current detection circuit 7 having such a configuration functions as current value detection means according to the present invention.

As described above, according to the present embodiment, the valve opening current diagnosis window and the holding current diagnosis window are provided, and in each window, the drive current characteristic actually detected and the characteristic that would be obtained in a normal state. With this configuration, it is possible to easily and accurately diagnose whether there is an abnormality or failure in the injector drive unit 1 or the like.

Although the present embodiment has been described as having a configuration in which both the valve opening current diagnosis window and the holding current diagnosis window are provided, the configuration may be such that only one of them is provided. Needless to say, it is possible to diagnose whether there is an abnormality or failure in the drive unit 1 or the like. By the way, in the present embodiment, when it is determined that the abnormality is detected in the valve opening current diagnosis window and it is determined that the voltage is normal in the holding current diagnosis window, the boosting circuit 6 or the second
If it is diagnosed that there is a high possibility that the transistor (Tr2) system has an abnormality (that is, a failure or abnormality related to the valve opening current of the drive control device 1), and if the abnormality is diagnosed in the holding current diagnosis window, It can be diagnosed that there is a high possibility that the battery voltage 5 or the first transistor (Tr1) system has an abnormality (that is, a failure / abnormality related to the holding current of the drive control device 1). According to the failure diagnosis circuit 8, it is also possible to specify an abnormal part.

In this embodiment, the failure diagnosis of the failure diagnosis circuit 8 itself can be performed as follows. That is, the failure diagnosis of the failure diagnosis circuit 8 itself is performed based on the following principle (see the system configuration diagram of FIG. 7). Ignition switch (IGN.SW) 9 is OF
F (operation by the driver or the like).

Then, the relay (D / U RLY) 10 for switching the power supply / stop to the injector drive unit (D / U) 1 is turned off, and the injector power is cut off. However, the logic power supply (control circuit power supply) VB remains connected. That is, the IGN. After a predetermined period has elapsed since the SW9 was turned off, the logic power supply VB is turned off after waiting for the end of the self (failure) diagnosis.

From the engine control unit 2,
An injection signal for D / U failure diagnosis is transmitted. At this time, the injector drive current is maintained at 0 since the injector drive power supply is cut off. Therefore, if the failure diagnosis circuit 8 is normal, the diagnosis signal transmitted from the failure diagnosis circuit 8 to the control unit 2 should be maintained at Hi.

Therefore, even in a single cylinder, the diagnostic signal is Lo.
When one shot pulse of the w signal is generated, it can be diagnosed that the failure diagnosis circuit 8 has an abnormality. That is, the control unit 2 also has functions as the first to third function maintaining means, the diagnostic injection command generating means, and the first to third failure diagnosing means according to the present invention.

The above-described principle is one example of which is shown in FIG.
The timing chart will be described. Here, the failure diagnosis control of the failure diagnosis circuit 8 according to the present embodiment will be described in more detail with reference to the timing chart of FIG. That is, the ignition switch (IGN.S)
W) The D / U relay (D / U RLY) 10 is turned off after a predetermined time has elapsed since the D / 9 was turned off.
After the U-relay (D / U RLY) 10 is turned off and a diagnostic injection pulse (injection signal) application delay period has elapsed, the control unit 2 sends a diagnostic injection pulse signal (injection signal) to the # 1 cylinder, for example. ) Is transmitted with a predetermined pulse width.

Further, a diagnostic injection pulse signal (injection signal) is sequentially transmitted with a predetermined pulse width to the # 2 to # 6 cylinders and the # 1 cylinder at predetermined diagnostic injection pulse generation intervals. The ignition switch (IGN.S)
W) In the first injection pulse application cylinder (# 1 cylinder in this example) after the 9 is turned off, the same valve-opening current flows as usual due to the charge remaining in the capacitor. Such initial injection pulse is ignored because it may cause a diagnosis.

That is, the start of diagnosis is delayed until the rise of the diagnostic injection pulse signal (injection signal) given to the # 2 cylinder. From the rise of the diagnostic injection pulse signal (injection signal) given to the # 2 cylinder fuel injection valve (injector solenoid) 4, the diagnosis given to the # 1 cylinder fuel injection valve (injector solenoid 4) Until the fall of the use ejection pulse signal (ejection signal), the failure diagnosis period is set.

During this failure diagnosis period, the EGI relay (EGI RLY; power supply relay) 11 is turned on,
That is, the logic power supply (control circuit power supply) VB is connected and then turned off. More specifically, with reference to FIG. 9, when the ignition switch (IGN.SW) 9 is turned on, a power supply relay (EGI relay) is supplied by power supply from the ignition switch (IGN.SW) 9. ) 11 is turned on, and the microcomputer of the engine control unit 2 starts operating. When the ignition switch (IGN.SW) 9 is turned off, the microcomputer of the engine control unit 2 keeps running until the microcomputer itself of the engine control unit 2 turns off the power. .

As described above, during the fault diagnosis period, if the fault diagnostic circuit 8 is normal, if the Lo signal is output to the diagnostic signal to be maintained at Hi, it is determined that the fault diagnostic circuit 8 is abnormal. Diagnose. The failure diagnosis control performed by the failure diagnosis circuit 8 and the failure diagnosis control of the failure diagnosis circuit 8 will be described with reference to the flowcharts of FIGS.

The flowchart of FIG. 10 is a routine executed when the ignition switch (IGN.SW) 9 is turned from OFF to ON. In S1, the timers 1 to 4 are reset (for each timer, see FIG. 17). In S2, “diagnosis permission flag A
{Flag for determining whether to permit failure diagnosis of injector drive unit 1 by failure diagnosis circuit 8}, diagnosis permission flag B (for determining whether to permit failure diagnosis of failure diagnosis circuit 8 itself) Flag)], [E
"GI relay OFF permission flag", "injector drive unit failure determination flag", and "check engine lamp lighting flag A (lighting flag for notifying failure of injector drive unit 1)" are set to 0,
To return.

FIG. 11 is a flowchart for explaining the EGI relay control, which is executed, for example, every 10 msec. Note that this flow functions as the first to third function maintaining means according to the present invention. S1
In 1, the ignition switch (IGN.SW) 9
Is determined to be OFF or ON. If it is ON, the process returns. If it is OFF, the process proceeds to S12.

In S12, for example, engine stall determination (determination as to whether or not the engine is stopped) is performed based on the engine rotation speed and the like. If engine stall (engine stopped), S
Proceed to 13 and return if the engine is rotating.
In S13, the EGI relay OFF permission flag is determined. If it is 0, the process returns. If it is 1, the process proceeds to S14.

In S14, the EGI relay is turned off,
Turn off the ignition switch (IGN.SW) 9
Even after the. The power supply to the engine control unit 2 that has been continuously supplied for the failure diagnosis of the failure diagnosis circuit 8 itself is stopped, and the present flow ends. The flowchart of FIG. 12 shows a routine for setting a diagnosis permission flag A for determining whether or not to permit the failure diagnosis of the injector drive unit 1 by the failure diagnosis circuit 8, and is performed at regular intervals (for example, 10 msec). This is executed when the diagnostic interrupt job shown in the flowchart is not performed (Back Ground Job; BGJ).

In S21, it is determined whether the ignition switch (IGN.SW) 9 is OFF or ON. ON
If so, it is determined that the engine is operating and that the failure diagnosis of the injector drive unit 1 using the failure diagnosis circuit 8 can be performed, and the process proceeds to S22. If it is OFF, the engine is stopped or immediately after switching from operation to stop, the injector drive unit 1 using the failure diagnosis circuit 8
Since the failure diagnosis cannot be performed, the process proceeds to S25.

At S22, the current cooling water temperature is compared with a predetermined value (TWDDU). Current cooling water temperature ≧ T
If it is a WDGDU, the process proceeds to S23, where the current cooling water temperature <T
If it is a WDGDU, the process proceeds to S25. The reason why the diagnosis is performed only when the temperature is equal to or higher than the predetermined water temperature is to improve the accuracy of the failure diagnosis by the failure diagnosis circuit 8. S
At 23, the battery voltage and a predetermined value (VBDGDU)
And. If the battery voltage ≧ VBDGDU, the process proceeds to S24, and if the battery voltage <VBDGDU, the process proceeds to S24.
Proceed to 25. The reason why diagnosis is performed only when the battery voltage is equal to or higher than a predetermined value is to improve the accuracy of failure diagnosis by the failure diagnosis circuit 8.

In S24, the diagnosis permission flag A is set to 1 (diagnosis permitted by the failure diagnosis circuit 8), and the flow ends. In S25, the diagnosis permission flag A is set to 0 (diagnosis is not permitted by the failure diagnosis circuit 8), and the flow ends. The flowchart of FIG.
This is a routine for executing its own failure diagnosis. This routine is executed, for example, every 10 msec.

In S31, the ignition switch (IGN.SW) 9 is turned OFF, ON, ON → OF.
F is determined. If OFF, proceed to S33, ON
If so, it is determined that the failure diagnosis circuit 8 is not in a state where the failure diagnosis of the failure diagnosis circuit 8 itself can be performed (the engine is operating),
If N → OFF, the process proceeds to S32. In S32, the timers 1 to 3 start counting.

In S33, the count value of the timer 1 and
A predetermined value (DGNDLY1) is compared. Then, if the count value of the timer 1 ≧ DGNDLY1, S34.
Then, if the count value of the timer 1 <DGNDLY1, the process returns. In S34, the timer 1 is stopped. In S35, the diagnostic injection signal (injection pulse) is set to ♯
Output is sequentially performed at predetermined intervals for the 1st to # 6 cylinders and the # 1 cylinder (see the timing chart of FIG. 8). Note that FIG.
As shown in the figure, the pulse width of the diagnostic injection signal (ON period)
In this case, a sufficient width (ON period) is provided so that the holding current diagnosis can be performed with high accuracy.

At S36, the count value of the timer 2 and
A predetermined value (DGNDLY2) is compared. Then, if the count value of the timer 2 ≧ DGNDLY2, S37
Then, if the count value of the timer 2 <DGNDLY2, the process returns. In S37, the timer 2 is stopped. In S38, the diagnosis permission flag B is set to 1 (allowing the failure diagnosis of the failure diagnosis circuit 8 itself).

In S39, it is determined whether the diagnostic circuit failure determination flag (flag indicating the result of determining whether or not the failure diagnosis circuit 8 itself has failed) is 0 or 1. If it is 0, the process proceeds to S40. If it is 1, the process proceeds to S43 because a failure has been determined. In S40, the count value of the timer 3 is compared with a predetermined value (DGNTIM). And timer 3
If the count value of ≧ DGNTIM, the process proceeds to S41, and if the count value of the timer 3 <DGNTIM, returns.

In S41, the timer 3 is stopped. S4
In 2, the check engine lamp lighting flag B (a lamp lighting flag for displaying a failure of the failure diagnosis circuit 8) →
0 (note that this flag is set in the OF of the IGN.SW9).
Back up after F). On the other hand, in S43, since the diagnosis circuit failure determination flag is 1 and the failure diagnosis circuit 8 itself has been diagnosed as having failed, the check engine lamp lighting flag B (displays the failure of the failure diagnosis circuit 8) Lamp lighting flag) → 1.

When the check engine lamp lighting flag B is 1, the check engine lamp is turned on to determine whether there is an abnormality in the failure diagnosis circuit 8 and it is not possible to diagnose whether the injector drive unit 1 is operating normally. , So that the driver can recognize it. This flag is set to IGN. It is preferable that the backup is performed even after the switch SW9 is turned off, so that even if an abnormality occurs in the injector drive unit 1, it may not be accurately detected.

In step S44, the diagnostic failure determination flag is changed from 0 to 0 to prepare for the failure diagnosis of the next and subsequent failure diagnostic circuits 8 themselves. In S45, the diagnosis permission flag B → 0 is set so as to prepare for the next and subsequent failure diagnosis of the failure diagnosis circuit 8 itself. In S46, the EGI relay OFF permission flag is set to “1”, and the EGI relay 11 is turned off to stop the power supply to the engine control unit 2 in the flowchart of FIG. finish.

The flowchart of FIG. 14 is a routine (diagnosis routine) for turning on the check lamp when the injector drive unit 1 fails, and is executed, for example, every 10 msec. In S51, it is determined whether the diagnosis permission flag A is 0 or 1. If it is 1, the diagnosis is permitted, and the process proceeds to S52. On the other hand, if the value is 0, the diagnosis is not permitted, and the routine returns.

In S52, it is determined whether the injector drive unit failure determination flag is 1 or 0. If 0,
Since the injector drive unit 1 is normal, this flow ends. On the other hand, if it is 1, since the injector drive unit 1 is abnormal, the process proceeds to S53. S
At 53, the check engine lamp lighting flag A → 1 is set (the check engine lamp is turned on in response to the failure of the injector drive unit 1), and the flow ends. It should be noted that the check engine lamp lighting flag A may be erroneously diagnosed due to, for example, a failure of the failure diagnosis circuit 8. It is preferable that the backup result is not performed while the switch SW9 is OFF, and that the diagnosis result performed again after the start is reflected.

The flowchart of FIG. 15 shows a diagnostic interrupt setting interrupt job, which is executed when the injection signal falls. The result of this job (change of the diagnostic interrupt flag from 0 to 1) is used to determine the execution start of the failure diagnosis of the injector drive unit 1 and the failure diagnosis circuit 8 in the flowchart of FIG. That is, in S61, it is determined whether any one of the diagnosis permission flags A and B is 1. If the diagnosis permission flags A and B are both 0, no diagnosis permission has been issued, and the routine returns to prevent erroneous diagnosis and the like. If it is 1, the process proceeds to S62.

In S62, the timer 4 starts counting. In S63, the count value of the timer 4 is compared with a predetermined value (DGNDLY4). If the count value of the timer 4 ≧ DGNDLY4, the process proceeds to S64, and if the count value of the timer 4 <DGNDLY4, the process returns. In S64, the diagnostic interrupt flag is set to "1".

In S65, the timer 4 is cleared, and this flow ends. The flowchart of FIG. 16 shows a failure or failure diagnosis circuit 8 of the injector drive unit 1.
A diagnostic interrupt job for diagnosing its own failure,
According to the flowchart of FIG. 15, the diagnostic interrupt flag is 0 →
It is executed when it becomes 1. In addition, such a flow,
It will function as the first to third failure diagnosis means according to the present invention.

In S71, it is determined whether the diagnosis permission flag A is 0 or 1. If it is 1, proceed to S72; if it is 0, S
Proceed to 74. In S72, it is determined whether the diagnostic signal is Hi or Lo. If it is Lo, it is diagnosed that the injector drive unit 1 is operating normally, and the process proceeds to S77. On the other hand, if Hi, the injector drive unit 1 is diagnosed as being abnormal (having a failure or the like), and the process proceeds to S73.

At S73, the injector drive unit failure determination flag is set to "1", and the routine proceeds to S77. In S74, it is determined whether the diagnosis permission flag B is 0 or 1. If it is 1, since the failure diagnosis of the failure diagnosis circuit 8 itself is permitted, the process proceeds to S75. On the other hand, if it is 0, the injector drive unit 1 is also
Since the failure diagnosis circuit 8 is not in a state of diagnosing a failure, the process directly proceeds to S77.

At S75, it is determined whether the diagnostic signal is Hi or Lo. If Lo, the injector drive power is normal, even though the injector drive power is not supplied (if the failure diagnosis circuit 8 is normal, the diagnostic signal should be fixed to Hi). Therefore, the failure diagnosis circuit 8 diagnoses that there is a failure or the like, sets the failure diagnosis circuit failure determination flag → 1 and sets
Proceed to S77.

On the other hand, if the diagnosis signal is Hi, the failure diagnosis circuit 8 itself diagnoses that it is operating normally, and proceeds to S77. In S77, the diagnostic interrupt flag is set to 0, and this flow ends in preparation for the next and subsequent failure diagnosis. As described above, according to the present embodiment, the valve opening current diagnosis window and the holding current diagnosis window are provided, and in each window, the drive current characteristics actually detected and the characteristics that can be obtained in a normal state. , It is possible to easily and accurately diagnose whether there is an abnormality or failure in the injector drive unit 1 or the like.

Further, according to the present embodiment, when the abnormality is diagnosed in the valve opening current diagnosis window and the normal is determined in the holding current diagnosis window, the booster circuit 6 and the second transistor (Tr2) system are used. It can be diagnosed that there is a high possibility that there is an abnormality in the battery voltage, and if the abnormality is diagnosed in the holding current diagnosis window, it is diagnosed that there is a high possibility that the battery voltage 5 or the first transistor (Tr1) system has an abnormality. Can be.
Therefore, according to the failure diagnosis circuit 8 according to the present embodiment,
It is also possible to specify an abnormal point.

Although the present embodiment has been described as having a configuration in which both the valve opening current diagnosis window and the holding current diagnosis window are provided, the configuration may be such that only one of them is provided. Needless to say, it is possible to diagnose whether there is an abnormality or failure in the drive unit 1 or the like. Further, according to the present embodiment, the failure diagnosis of the failure diagnosis circuit 8 itself can be easily and accurately performed.

That is, according to the present embodiment, the ignition switch (IGN.SW) 9 is turned off, the power supply to the injector drive unit 1 is stopped, and even after the injector drive power supply is cut off, the predetermined period is maintained. , The engine control unit 2 forcibly transmits a failure diagnosis injection signal to the injector drive unit 1 while the logic power supply (control circuit power supply) remains connected via the EGI RLY 11. At this time,
Since the injector drive power supply is cut off, the injector drive current is maintained at 0 even if the failure diagnosis injection signal is transmitted. Therefore, if the failure diagnosis circuit 8 is normal, the injector drive unit 1 is determined to have failed. Diagnosis and the diagnostic signal transmitted from the failure diagnostic circuit 8 to the control unit 2 should be maintained at Hi. Therefore, even in the case of one cylinder, when a one-shot pulse of the Low signal is generated in the diagnosis signal, it can be diagnosed that the failure diagnosis circuit 8 is abnormal.

That is, in the present embodiment, when an injection signal is forcibly given to the injector drive unit 1 under the condition that the injector drive current does not flow, the failure diagnosis circuit for detecting the injector drive current characteristic and performing the failure diagnosis. 8, when it is diagnosed that the injector drive current is controlled and the injector drive unit 1 is operating normally, the failure diagnosis circuit 8 is diagnosed as having an abnormality. 8 itself can be diagnosed.

Further, in this embodiment, the failure diagnosis method for the injector drive unit 1 and the failure diagnosis method for the failure diagnosis circuit 8 itself differ only in the conditions for performing the diagnosis (whether the engine is running or the ignition switch is OFF). Since the diagnosis method is basically the same, there is no need to separately add a new circuit for failure diagnosis of the failure diagnosis circuit 8 itself, so that the configuration can be simplified and the cost can be reduced. is there.

Immediately after the condition under which the injector drive current does not flow, that is, after the start of the failure diagnosis of the failure diagnosis circuit 8 itself, the first injection pulse application cylinder supplies the injector drive current with the charge remaining in the capacitor. The injector drive current is supplied in the same manner as at the time, so that the injector drive current is controlled normally, and the failure diagnosis circuit 8 may diagnose that the injector drive unit 1 is operating normally. However, in such a case, since the injector drive unit 1 is actually operating normally, the failure diagnosis circuit 8 may diagnose that the injector drive unit 1 is operating normally. In its own failure diagnosis, the failure diagnosis circuit 8 may be erroneously diagnosed as having a failure even in such a normal state.

On the other hand, in the present embodiment, immediately after the condition that the injector drive current does not flow, that is, for the first injection pulse application cylinder after the failure diagnosis of the failure diagnosis circuit 8 itself is started, the failure diagnosis circuit Since the failure diagnosis of the failure diagnosis circuit 8 itself is not performed, the above-described erroneous diagnosis can be reliably prevented, so that the diagnosis accuracy of the failure diagnosis of the failure diagnosis circuit 8 itself can be greatly improved. Can be.

In the present embodiment, the failure diagnosis of the injector drive unit 1 or the failure diagnosis of the failure diagnosis circuit 8 itself is performed by detecting whether or not the Lo signal of the diagnostic signal is generated.
The presence or absence of an abnormality is diagnosed based on the detection result. As shown in FIG. 8 (part A), after a predetermined period has elapsed from the fall of the injection signal (the Lo signal is definitely Lo). When the presence / absence of the generation of the Lo signal can be detected, the presence / absence of the generation of the Lo signal can be detected with higher accuracy. Therefore, the failure diagnosis of the injector drive unit 1 or the failure diagnosis circuit 8 itself can be performed. The diagnostic accuracy of the failure diagnosis can be further improved.

In the present embodiment, a six-cylinder internal combustion engine having a fuel injection valve (injector solenoid) 4 in each cylinder has been described. However, the present invention is not limited to this, and at least one fuel injection valve is provided. (Injector solenoid) 4 Combustion engine equipped with 4 fuel injection method (direct injection in cylinder, injection in intake port, etc.), combustion mode (stratified combustion, homogeneous combustion, diffusion combustion, etc.), fuel type (gasoline, light oil, alcohol, The present invention is applicable as long as it is not limited to natural gas.

In this embodiment, the failure diagnosis is performed based on whether the valve opening current or the holding current has reached a predetermined value in the valve opening current diagnosis window or the holding current diagnosis window. However, the present invention is not limited to this, and a failure diagnosis can be performed based on, for example, change characteristics (temporal change, inclination, etc.) of the valve opening current and the holding current.

[Brief description of the drawings]

FIG. 1 is a block diagram of the present invention.

FIG. 2 is a block diagram of the present invention.

FIG. 3 is a block diagram of the present invention.

FIG. 4 is a system configuration diagram according to an embodiment of the present invention.

FIG. 5 is a timing chart illustrating drive control of a fuel injection valve in the embodiment.

FIG. 6 is a timing chart illustrating fault diagnosis control by the fault diagnosis circuit 8 in the embodiment.

FIG. 7 is a system configuration diagram relating to a failure diagnosis of the failure diagnosis circuit 8 according to the embodiment.

FIG. 8 is a timing chart for explaining fault diagnosis control of the fault diagnosis circuit 8 according to the first embodiment;

FIG. 9 is a configuration diagram for explaining driving of an EGI relay in the embodiment.

FIG. 10 is a flowchart (initialization) in the embodiment.

FIG. 11 is a flowchart (EGI) in the embodiment.
Relay control)

FIG. 12 is a flowchart (self-diagnosis permission control) in the embodiment.

FIG. 13 is a flowchart (diagnosis of a diagnostic circuit) in the embodiment.

FIG. 14 is a flowchart (diagnosis of a drive control circuit) in the embodiment.

FIG. 15 is a flowchart (diagnostic interrupt setting interrupt job) in the embodiment.

FIG. 16 is a flowchart (diagnosis interrupt job) in the embodiment.

FIG. 17 is a diagram illustrating various timers and the like in the embodiment.

FIG. 18 is a timing chart showing an example of how to give a diagnostic injection signal / holding current diagnostic window in the embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 injector drive unit (drive control device for fuel injection valve) 2 engine control unit (control device for engine) 3 control circuit 4 injector solenoid (fuel injection valve) 5 battery voltage 6 booster circuit 7 current detection circuit (current value detection means) 8 Failure diagnosis circuit (valve opening current diagnosis means, holding current diagnosis means) 9 ignition switch 10 D / U relay 11 EGI relay Tr1, Tr2 transistor

Claims (7)

[Claims] The present invention provides a solenoid valve provided with a valve opening current from a time when a fuel injection start command is input from an engine control unit to a solenoid having a relatively large predetermined value to open the fuel injection valve. After the valve opening current reaches a predetermined value, a relatively small holding current capable of holding the valve open state is given to the solenoid,
A diagnostic device for a drive control device for a fuel injection valve configured to maintain a held current value until a fuel injection stop command is input from an engine control unit, and detects a current value given to the solenoid. Current value detecting means, a current value characteristic in a normal state from when the fuel injection start command is input to when the valve opening current reaches the predetermined value, and a current actually detected by the current value detecting means. And a valve opening current diagnosis means for diagnosing the presence or absence of a failure related to the valve opening current of the drive control device for the fuel injection valve, based on the value characteristic, and Diagnostic device for drive control device. 2. A fuel injection valve according to claim 1, wherein a valve opening current is applied to a solenoid provided in the fuel injection valve until a relatively large predetermined value is reached from when a fuel injection start command is input from the engine control unit. After the valve opening current reaches a predetermined value, a relatively small holding current capable of holding the valve open state is given to the solenoid,
A diagnostic device for a drive control device for a fuel injection valve configured to maintain a held current value until a fuel injection stop command is input from an engine control unit, and detects a current value given to the solenoid. The fuel injection valve based on a holding current value maintained until a fuel injection stop command is input in a normal state, and a current value actually detected by the current value detecting means. And a holding current diagnosing means for diagnosing the presence or absence of a failure related to the holding current of the drive control device. 3. A fuel injection valve is opened by applying a valve opening current to a relatively large predetermined value to a solenoid of the fuel injection valve from when a fuel injection start command is input from an engine control unit. After the valve opening current reaches a predetermined value, a relatively small holding current capable of holding the valve open state is given to the solenoid,
A diagnostic device for a drive control device for a fuel injection valve configured to maintain a held current value until a fuel injection stop command is input from an engine control unit, and detects a current value given to the solenoid. Current value detecting means, a current value characteristic in a normal state from when the fuel injection start command is input to when the valve opening current reaches the predetermined value, and a current actually detected by the current value detecting means. Valve current diagnosis means for diagnosing the presence or absence of a failure related to the valve opening current of the drive control device for the fuel injection valve based on the value characteristics, and maintained until a fuel injection stop command is input in a normal state. Based on the holding current value and the current value actually detected by the current value detecting means, it is diagnosed whether there is a failure related to the holding current of the drive control device of the fuel injection valve. Diagnostic device for a drive control device of the fuel injection valve, characterized in that configured to include a holding current diagnosis means that, the. 4. The functions of the engine control unit, the drive control device for the fuel injection valve, the valve opening current diagnosis means, and the current value detection means for a predetermined period after the connection between the solenoid and the power supply is cut off. After disconnection of the solenoid and the power supply, the diagnostic unit starts a diagnostic injection start command and a diagnostic injection stop command at predetermined intervals in the control unit in which the function is maintained. A diagnostic injection command generating means for generating, after disconnection of the solenoid and the power supply, when the diagnostic injection start command is input to the drive control device of the fuel injection valve, the valve opening When the current diagnosis unit diagnoses that there is no failure related to the valve opening current of the drive control device for the fuel injection valve, the first failure diagnosis diagnoses that the valve opening current diagnosis unit has failed. Diagnostic device of the diagnostic device of the drive control device of a fuel injection valve according to claim 1 or claim 3, characterized in that configured to include a means. 5. The function of the engine control unit, the drive control device for the fuel injection valve, the holding current diagnostic means, and the current value detecting means for a predetermined period after the connection between the solenoid and the power supply is cut off. After disconnecting the solenoid and the power supply, a second function maintaining means for maintaining the function, a diagnostic injection start command and a diagnostic injection stop command are issued at predetermined intervals in the control unit in which the function is maintained. The diagnostic injection command generating means to be generated, the disconnection of the solenoid, and the power supply, after the diagnostic injection start command is input to the drive control device of the fuel injection valve, the holding current diagnosis When the means diagnoses that there is no failure related to the holding current of the drive control device for the fuel injection valve, a second failure diagnosis for diagnosing that the holding current diagnosis means has failed. Diagnostic device of the diagnostic device of the drive control device of a fuel injection valve according to claim 2 or claim 3, characterized in that configured to include a means. 6. The engine control unit, the drive control device for the fuel injection valve, the valve opening current diagnosis unit, the holding current diagnosis unit, and the control unit for a predetermined period after the connection between the solenoid and the power supply is disconnected. A third function maintaining means for maintaining the function of the current value detecting means; and a diagnostic injection start command at predetermined intervals in the control unit in which the function is maintained after disconnection of the solenoid and the power supply. A diagnostic injection command generating means for generating a diagnostic injection stop command, and after disconnecting the solenoid and the power supply, the diagnostic injection start command is input to the drive control device of the fuel injection valve. In this case, the valve opening current diagnosis unit or the holding current diagnosis unit diagnoses that there is no failure related to the valve opening current or the holding current of the drive control device for the fuel injection valve. 4. The fuel injection valve according to claim 3, further comprising: a third failure diagnosis unit that diagnoses that the valve opening current diagnosis unit or the holding current diagnosis unit has failed. Diagnostic device for drive control device diagnostic device. 7. The diagnostic device for a drive control device for a fuel injection valve according to claim 5, wherein the predetermined interval is set to an interval at which the holding current diagnostic means can function sufficiently. Diagnostic device.