JPH1113524A - Drive control system for fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve back-up travel during abnormality in a high voltage system of a drive controller for a fuel injection valve. SOLUTION: Inside an opening valve current diagnostic window, if an opening valve current is lower than a judgment value, a failure diagnostic circuit diagnoses abnormality in a high voltage system of a drive controller. At the time of abnormality in the high voltage system, generation of a high voltage is stopped, and then, a valve is opened only by a holding current for fuel injection. Since such valve opening operation by the holding current is delayed timewise with respect to valve opening operation by a valve opening current during normal operation, a valve opening time is corrected in consideration of that delay in order to enable back-up travel (S43). Furthermore, a process for securing a predetermined fuel injection quantity is carried out so as to enable the back-up travel (S45). Moreover, a fuel cutting process for limiting an engine speed to a given engine speed, at which the back-up travel can be performed, is performed so as to suppress an adverse effect on an engine (S46, S47). Consequently, it is possible to achieve the back-up travel while securing safety during abnormality in the high voltage system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control system for an electromagnetic (solenoid) type fuel injection valve, and more particularly to a drive control system capable of backing up (self-running to a maintenance shop or the like) when an abnormality occurs in a drive control system device. To a control device.

[0002]

2. Description of the Related Art A conventional drive control system for an electromagnetic fuel injection valve used in an internal combustion engine is disclosed, for example, in Japanese Unexamined Patent Publication No.
There is one as disclosed in JP-A-10-15552.
Such a conventional fuel injection valve drive control system 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 the valve is opened well, when the current value of the drive current thereafter 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, The current value is maintained during the valve opening time so that a desired fuel injection amount can be achieved.

[0003]

However, the above-described conventional fuel injection valve drive control system does not include a self-diagnosis device, and diagnoses whether the drive control system is operating normally. I couldn't do that. For this reason, there is a fear that the user or the like may be delayed in recognizing the operation failure or the like, and the treatment for various situations (for example, deterioration in drivability, fuel consumption, exhaust performance, or the like) may be delayed. is there.

When a self-diagnosis device is provided and it is diagnosed that the drive control system is not operating normally, backup traveling (for example, to a maintenance shop or the like) is performed within a range where no adverse effects occur. It is hoped that it will be possible to carry it on its own. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a simple and inexpensive configuration to enable backup running when a failure (abnormal) of a fuel injection valve drive control system occurs.

[0005]

Therefore, according to the first aspect of the present invention, when a fuel injection start command is input from an engine control unit, a relatively large predetermined value is applied to a solenoid provided in 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 drive control system for a fuel injection valve that maintains the holding current value until a fuel injection stop command is input from a unit, wherein an abnormality occurs in a system that provides a valve opening current of the drive control system to the solenoid. When it occurs, stop giving valve opening current to the fuel injection valve,
The fuel injection valve is opened by applying the holding current, and the period from the fuel injection start command to the fuel injection stop command is corrected in consideration of the valve opening delay due to the valve opening operation by the holding current. I did it.

According to the second aspect of the present invention, as shown in FIG. 1, 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 opening 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 opening state is given to the solenoid, and the engine control unit sends A drive control system for a fuel injection valve that maintains the holding current value until a fuel injection stop command is input, wherein an abnormality occurs in a system that provides a valve opening current of the drive control system to the solenoid. Diagnostic means for diagnosing whether or not an abnormality has occurred in a system for providing a valve opening current of a drive control system to the solenoid by the diagnostic means; A backup control means for stopping application of a valve-opening current to the fuel injection valve and applying a holding current to open the fuel injection valve; and An injection command correcting means for correcting a period from a fuel injection start command to a fuel injection stop command in consideration of a valve opening delay due to the valve operation.

According to the first and second aspects of the present invention, when a system (high voltage system) for providing a valve opening current of the drive control system to the solenoid is abnormal, the valve opening current is supplied to the fuel injection valve. To ensure safety (to avoid electric shock due to disconnection of the harness, disconnection of the connector, etc., and to avoid the risk of sparks), but also due to the valve opening delay caused by the valve opening operation performed only with the holding current As a result, the desired fuel injection amount can be achieved by correcting the decrease in the fuel injection amount, so that the backup traveling can be performed while ensuring safety.

According to the third aspect of the present invention, the diagnostic means includes a current value detecting means for detecting a current value applied to the solenoid, and a valve opening current from when the fuel injection start command is input. Is based on a current value characteristic in a normal state until the predetermined value is reached, and a current value characteristic actually detected by the current value detection means, and a system for providing a valve opening current of a drive control system to the solenoid. And valve opening current diagnosis means for diagnosing the presence or absence of an abnormality.

According to this configuration, the current characteristic that is actually detected and the current characteristic that would be obtained in a normal state are compared, and the valve opening current of the drive control system can be easily and accurately determined. System applied to solenoid (high voltage system)
It is possible to diagnose the presence / absence of an abnormality / failure. Claim 4
In the invention described in (1), the period from the fuel injection start command to the fuel injection stop command is corrected by changing a so-called invalid injection pulse width.

With such a configuration, with simple logic,
Since the period from the fuel injection start command to the fuel injection stop command can be corrected, it is possible to reduce the calculation processing time and the product cost. Claim 5
In the invention described in (1), when an abnormality occurs in a system (high-voltage system) that supplies a valve opening current of the drive control system to the solenoid, the fuel injection amount is controlled so as not to be equal to or less than the fuel injection amount capable of backing up. The period from the fuel injection start command to the fuel injection stop command is limited to a predetermined value or more.

With this configuration, even when the high-voltage system fails, the minimum fuel injection amount when the valve is opened only by the holding current (the minimum fuel injection amount that is guaranteed as the capacity of the used fuel injection valve) Can be secured, and the period during which the engine output required for backup traveling can be secured can be set. As a result, even when a failure occurs in the high-voltage system, it is possible to secure a fuel injection amount that can be backed up while suppressing the fuel injection amount from becoming unstable.

According to the present invention, when an abnormality occurs in a system (high voltage system) for supplying a valve opening current of the drive control system to the solenoid, the engine speed is limited to a predetermined value or less. The fuel cut control is performed. With such a configuration, at the time of a high-voltage system failure, the engine speed is increased to a predetermined value or more,
Thus, it is possible to reliably avoid a situation in which the engine and other parts are adversely affected. For example, it is possible to reliably prevent the deterioration of combustion caused by the extension of the valve opening time when a valve is opened only by the holding current, an increase in the discharge amount of unburned portion, and overheating of the catalyst.

According to a seventh aspect of the present invention, in the case of an engine that switches the combustion mode between a stratified combustion mode and a homogeneous combustion mode, a system (high-voltage system) that supplies a valve opening current of a drive control system to the solenoid. ) When something goes wrong,
The fuel injection timing is forcibly set to the homogeneous combustion timing. With this configuration, the injection timing is set earlier (for example, set during the intake stroke) than the injection timing during stratified combustion (for example, set during the compression stroke). ,
Since fuel injection can be performed, there is an advantage that a large amount of fuel can be injected even during the same valve opening time.

That is, even at the time of a high voltage failure in which the valve is opened only by the holding current, a predetermined fuel injection amount can be ensured in the shortest valve opening time. In other words, for example, when the fuel is injected at a high cylinder pressure, such as during the compression stroke, the fuel is injected against the high cylinder pressure, so the valve opening time is required to obtain the required injection amount. Is too long to be able to inject during the compression stroke.
Such fear can be reliably avoided. In addition, if the injection timing is set earlier, it is possible to promote the vaporization of the fuel (the promotion of the mixing of the fuel and the intake air). Can be done.

[0015]

According to the first and second aspects of the present invention, when a system (high-voltage system) for providing a valve opening current of the drive control system to the solenoid is abnormal, the valve opening current is supplied to the fuel injection valve. To ensure safety (to avoid electric shock due to disconnection of harness, disconnection of connector, etc., and to avoid the risk of sparks), while delaying valve opening due to valve opening operation performed only with holding current As a result, a desired fuel injection amount can be achieved by correcting a decrease in the fuel injection amount caused by the above, so that backup traveling can be performed while ensuring safety.

According to the third aspect of the present invention, a current characteristic that is actually detected and a current characteristic that can be obtained in a normal state are compared with each other. It is possible to diagnose whether there is an abnormality or failure in a system (high-voltage system) that supplies a valve opening current to the solenoid. According to the fourth aspect of the present invention, the period from the fuel injection start command to the fuel injection stop command can be corrected with a simple logic, so that the calculation processing time and the product cost can be reduced. Can be achieved.

According to the fifth aspect of the present invention, even when a failure occurs in the high-voltage system, the minimum fuel injection amount when the valve is opened only with the holding current (the capacity is guaranteed by the fuel injection valve used). A minimum fuel injection amount) can be ensured, and the engine output required for backup traveling can be ensured. As a result, even when a failure occurs in the high-voltage system, it is possible to secure a fuel injection amount that can be backed up while suppressing the fuel injection amount from becoming unstable.

According to the sixth aspect of the present invention, it is ensured that when the high-voltage system fails, the engine rotation speed is increased to a predetermined value or more, which adversely affects the engine and other parts. It is possible to avoid. For example, it is possible to reliably prevent the deterioration of combustion caused by the extension of the valve opening time when a valve is opened only by the holding current, an increase in the discharge amount of unburned portion, and overheating of the catalyst.

According to the present invention, the injection timing is set earlier (for example, during the intake stroke) than the injection timing during stratified combustion (for example, during the compression stroke). Therefore, the fuel injection can be performed in a state where the cylinder internal pressure is low, so that there is an advantage that a large amount of fuel can be injected even during the same valve opening time.

That is, even at the time of a high-voltage failure in which the valve is opened only by the holding current, a predetermined fuel injection amount can be ensured in the shortest valve opening time. In other words, for example, when the fuel is injected at a high cylinder pressure, such as during the compression stroke, the fuel is injected against the high cylinder pressure, so the valve opening time is required to obtain the required injection amount. Is too long to be able to inject during the compression stroke.
Such fear can be reliably avoided. Further, if the injection timing is set earlier, it is possible to promote the vaporization of the fuel (the promotion of the mixing of the fuel and the intake air), so that the problem of misfire and the like can be avoided more reliably than in the case of the injection at the injection timing for stratified combustion. be able to.

[0021]

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. 2, 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.

Specifically, for example, as shown in the timing chart of FIG. 3, 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.

If there is a failure (abnormality) in the drive control of the injector solenoid 4 by the control circuit 3,
For example, the injector behavior is as shown in FIG. That is, if there is any failure (abnormality) in the second transistor (Tr2), the booster circuit 6, or the like, as shown by the broken line in FIG. 4, a high valve-opening voltage cannot be generated. Since the valve body of the injector 4 cannot be opened, the valve opening timing (start of the injector valve lift) is delayed in time. Such a delay directly reduces the fuel injection amount (the required fuel injection amount cannot be achieved)
This leads to a decrease in drivability and the like, but particularly in a lean (lean air-fuel ratio) operation, an excessive lean state is caused, which may cause a lean misfire or the like. It should be noted that in an engine that performs stratified combustion, the combustible air-fuel mixture cannot be satisfactorily transported to the ignition plug, so that there is a concern that the effect is further increased. FIG. 5 shows an experimental result of comparing the fuel injection amount between a normal time and a failure (when no high voltage is generated = when the valve is opened only by the holding current).

For this reason, the injector drive unit 1 according to the present embodiment has a failure diagnosis circuit for diagnosing whether or not the above control (control shown in the timing chart of FIG. 3) by the injector drive unit 1 is normally performed. 8 are provided. The failure diagnosis circuit 8 functions as a diagnosis unit and a valve opening current diagnosis unit according to the present invention.

By the way, the stratified combustion means, for example, usually a homogeneous mixture (a state in which fuel is uniformly dispersed throughout the combustion) through a fuel injection valve directly facing a combustion chamber (in a cylinder). In a predetermined operation state (low rotation speed, low load state, etc.), a layer (1) composed of a combustible mixture ignitable by an ignition plug and an air layer containing EGR or an ignition plug Is difficult to ignite, but a stratified mixture consisting of layers of the layer (2), which is combustible by receiving the combustion flame in the layer (1), forms an extremely lean air-fuel ratio (near the lean limit). (Air-fuel ratio), which means that the combustion mode is designed to improve the fuel efficiency by reducing the pumping loss and the like (see Japanese Patent Application Laid-Open Nos. 62-191622 and 2-169834). .

Hereinafter, the fault diagnosis circuit 8 according to the present embodiment will be described.
The failure diagnosis control of the injector drive unit 1 performed by the controller will be described. Failure diagnosis circuit 8 according to the present embodiment
Then, as shown in the timing chart of FIG. 6, at the same time when the injection signal is turned ON, the valve opening current diagnosis window is set to Hi.
It is supposed to.

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).
(See the state indicated by the solid line in FIG. 3)), there is some abnormality, and it can be diagnosed that the high voltage system of the injector drive unit 1 is not functioning normally.

In the failure diagnosis circuit 8 according to the present embodiment, for example, when it is determined that there is an abnormality in the valve opening current window, the diagnosis signal is maintained at Hi while the valve opening current window is maintained. If the injection signal is temporarily turned OFF when the normal condition is diagnosed, the diagnostic signal is set to Lo (the Lo signal is output only for one shot).

This diagnostic signal is input to the engine control unit 2 as shown in FIG. 4. In the engine control unit 2, when the diagnostic signal remains Hi, the high voltage of the injector drive unit 1 is output. If there is any abnormality in the system, a high voltage stop signal is generated for all cylinders, and the second transistor (T
The ON signal to r2), the energization of the booster circuit 6, and the like are stopped (see the timing chart of FIG. 7), and at the same time, the warning light and the like are turned on and blinked, so that the driver and the like can recognize that there is an abnormality. , Measures and the like are encouraged. Note that a high voltage stop signal is generated, and the second transistor (Tr
By stopping the ON signal to 2), energizing the booster circuit 6, and the like, safety can be ensured (electric shock due to disconnection of a harness, disconnection of a connector, and the like, and fear of sparks or the like can be avoided).

In order to prevent erroneous diagnosis due to noise or the like, the above-described diagnosis is performed when a diagnostic signal (normal signal; Lo signal) is continuously lost N times for the same cylinder (N consecutive diagnostic signals for the same cylinder). Can be diagnosed as a failure when the signal remains ON). As described above, according to the present embodiment, the valve opening current diagnosis window is provided, and a current characteristic that is actually detected and a current characteristic that can be obtained in a normal state are compared in the window. It is possible to easily and accurately diagnose whether there is an abnormality or failure in the high voltage system of the injector drive unit 1.

Further, in the engine control unit 2 according to the present embodiment, when it is diagnosed that the high voltage system of the injector drive unit 1 is abnormal or faulty, the backup traveling (self-access to a maintenance shop or the like) is performed as follows. Run, etc.). Therefore, the engine control unit 2 functions as the backup control unit and the injection command correction unit according to the present invention.

Control for enabling such backup traveling will be described with reference to the block diagram of FIG. First, in block A, a basic fuel injection pulse width (basic fuel injection amount) Tp is calculated based on the intake air amount Q and the engine rotation speed N. Tp = Q / N × KK; constant In block B, various corrections are made to Tp to calculate the final fuel injection pulse width (fuel injection amount) Ti in a normal state.

Ti = 2 × Tp + Ts Ts; invalid injection pulse correction value When it is diagnosed that the high voltage system of the injector drive unit 1 is abnormal or faulty, Ts = Ts2
(Normal normal injection pulse correction value + Normal opening abnormal valve opening delay correction value; that is, a correction value including a valve opening delay when the valve is opened only with the holding current with respect to the normal time).

In block C, the fuel injection pulse width is limited. By setting the fuel injection amount equal to or larger than the minimum fuel injection amount of the fuel injection valve 4, stable fuel injection is realized. That is, the fuel injection pulse width is limited to Ti ≧ TIMIN. In addition, TIMIN is set to a value that can ensure an injection pulse width equal to or larger than a normal fuel injection amount that can achieve the normal minimum fuel injection amount in a normal state, and diagnoses that the high voltage system of the injector drive unit 1 is abnormal or faulty. Is set to a value equal to or larger than the injection pulse width that can secure the minimum fuel injection amount when the valve is opened only with the holding current and can secure the engine output required for the backup traveling. Has become.

In block D, the fuel injection timing is calculated. When it is diagnosed that the high voltage system of the injector drive unit 1 is abnormal or faulty, the injection timing for homogeneous combustion is set. As a result, the injection timing is set earlier (set during the intake stroke) than the injection timing during stratified combustion (set during the compression stroke), so that the fuel injection is performed in a state where the cylinder pressure is low. Therefore, there is an advantage that more fuel can be injected even during the same valve opening time.

That is, even when the valve is opened only by the holding current, a predetermined fuel injection amount can be ensured in the shortest valve opening time. In other words, for example, when the fuel is injected at a high cylinder pressure, such as during the compression stroke, the fuel is injected against the high cylinder pressure, so the valve opening time is required to obtain the required injection amount. However, there is a possibility that the fuel cell cannot be completely injected during the compression stroke due to excessively large length. However, such fear can be avoided. In addition, if the injection timing is set earlier, it is possible to promote the vaporization of the fuel (the promotion of the mixing of the fuel and the intake air). Can be done.

In the next block E, a fuel cut (fuel cut) process is performed. That is, when it is diagnosed that there is an abnormality or failure in the high voltage system of the injector drive unit 1, the fuel is cut at the engine rotation speed N ≧ NEHMAX. Thus, it is possible to reliably avoid a situation in which the engine speed is increased to a predetermined value or more at the time of a high-voltage system failure, thereby adversely affecting the engine and other components. Deterioration of combustion due to a prolonged valve-opening time when a valve is opened only by current can be prevented reliably, so that an increase in the amount of unburned fuel discharged and overheating of the catalyst can be reliably prevented.

Here, the above-described control will be described with reference to the flowcharts of FIGS. The flowchart of FIG. 9 shows an ignition switch (IGN.S).
W) This is a routine executed when 9 changes from off to on. In S1, Ts is set to Ts1 (normal), and TIMIN is set to TIMIN1 (normal). In S2, the "diagnosis permission flag", the "injector drive unit failure determination flag", and the "check engine lamp lighting flag" are set. Set to 0 and return.

FIG. 10 is a flowchart showing a routine for setting a diagnosis permission flag for determining whether or not to permit the failure diagnosis of the injector drive unit 1 by the failure diagnosis circuit 8 for a predetermined time (for example, 10 msec).
Each time, the diagnostic interrupt job shown in the flowchart of FIG.
(Back Grou
nd Job; BGJ).

In S11, 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 S12. If it is off, since 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 S15.

In S12, 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 S13, where the current cooling water temperature <T
If it is a WDGDU, the process proceeds to S15. 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 13, the battery voltage and a predetermined value (VBDGDU)
And. If battery voltage ≧ VBDGDU, proceed to S14, if battery voltage <VBDGDU, proceed to S14.
Proceed to 15. 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 S14, the diagnosis permission flag is set to 1 (diagnosis permitted by the failure diagnosis circuit 8), and the flow ends. In S15, the diagnosis permission flag is set to 0 (diagnosis is not permitted by the failure diagnosis circuit 8), and the flow ends. The flowchart of FIG. 11 is a diagnostic interrupt setting interrupt job for self-diagnosis, which is executed when the injection signal falls.

That is, in S21, it is determined whether the diagnosis permission flag is "1". If the diagnosis permission flag is 0, the diagnosis is not permitted, and the process returns to prevent erroneous diagnosis. If it is 1, the process proceeds to S22. In S22, 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 routine returns.

On the other hand, if it is Hi, it is diagnosed that the injector drive unit 1 is abnormal (failure or the like), and the routine proceeds to S23. In S23, the injector drive unit failure determination flag is set to → 1, and the routine returns. The flowchart of FIG. 12 is a routine (diagnosis routine) for turning on the check lamp when the injector drive unit 1 fails, for example, 10 ms.
This is executed every ec.

At S31, 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 S32. S
At 32, the check engine lamp lighting flag is set to "1" (the check engine lamp is turned on in response to the failure of the injector drive unit 1), and the flow ends. The check engine lamp lighting flag may be set to IGN.
It is preferable that the backup result is not performed while the switch SW9 is turned off, and that the diagnosis result performed again after the start is reflected.

In S33, since the high voltage system of the injector drive unit 1 is abnormal, “Ts = Ts1 (normal invalid injection pulse correction value)” is changed to “Ts = Ts2 (normal invalid injection pulse correction value + normal time Valve opening delay correction value in the event of an abnormality). When the high voltage system of the injector drive unit 1 is diagnosed as having an abnormality or failure, the TIMIN can ensure the minimum fuel injection amount when the valve is opened only by the holding current, even when the high voltage system fails. The value TIMIN2 is equal to or larger than the injection pulse width that can secure the engine output necessary for the backup traveling.

The flowchart of FIG. 13 is a routine for explaining backup control and the like for enabling backup traveling when the injector drive unit 1 fails, and is executed, for example, every 10 msec.
In S41, the basic fuel injection pulse width Tp (= Q / N ×
K) is calculated. In S42, it is determined whether the injector drive unit failure determination flag is 1 or 0. If the value is 0, the injector drive unit 1 is normal, and the process proceeds to S43. On the other hand, if it is 1, since the injector drive unit 1 is abnormal, the process proceeds to S46.

In S46, the engine speed N ≧ NEH
It is determined whether or not it is MAX. If YES, there is an abnormality in the high voltage system.
Go to 47. In S47, in order to perform a fuel cut,
This flow is terminated with Ti = 0.

On the other hand, if it is determined in S46 that the answer is NO (engine speed N <NEHMAX), the flow proceeds to S43. In S43, the fuel injection pulse width Ti (= 2 × T
(p + Ts). In the normal state, “Ts = Ts
1 (invalid injection pulse correction value during normal operation) "and set to" Ts = Ts2 (invalid injection pulse correction value during normal operation + valve opening delay correction value during abnormal operation relative to normal operation) "in the abnormal state (in the flowchart). See figure). This allows
In the event of a failure in the high-voltage system, the decrease in fuel injection amount due to the valve opening delay caused by the valve opening operation being performed only with the holding current is restored to the desired level (at least backup running is possible)
The fuel injection amount can be achieved. By the way, if the fuel injection amount is corrected by changing Ts at the time of an abnormality, a desired (minimum backup running possible) fuel injection amount can be achieved with a simple logic, and the calculation processing time can be reduced. It is possible to reduce product cost and the like.

At S44, the fuel injection pulse width Ti ≧ TI
It is determined whether or not it is MIN. YES (Ti ≧ TIMIN)
If so, the present flow ends. NO (Ti <TIMI
If N), proceed to S45. In S45, Ti = TI
The flow ends as MIN. As a result, the minimum fuel injection pulse width, which is the capability of the fuel injection valve 4, is secured. In addition, TIMIN can secure the minimum fuel injection amount when the valve is opened only by the holding current, even when the high voltage system fails, when it is diagnosed that the high voltage system of the injector drive unit 1 is abnormal or faulty, And
The value TIMIN2 is set to a value TIMIN2 equal to or larger than the injection pulse width that can secure the engine output necessary for the backup traveling (S33 in FIG. 12). As a result, even when a failure occurs in the high-voltage system, it is possible to ensure the minimum fuel injection amount that allows backup traveling.

As described above, according to this embodiment, the valve opening current diagnosis window is provided, and the drive current characteristics actually detected and the characteristics that can be obtained in a normal state are provided in the window. With the configuration for comparison, it is possible to diagnose the abnormality / failure of the high voltage system of the injector drive unit 1 easily and with high accuracy. Further, according to the present embodiment, when it is diagnosed that the high voltage system of the injector drive unit 1 has an abnormality or a failure, safety is ensured (an electric shock due to a disconnection of a harness, a disconnection of a connector, or the like, or a spark, etc.). Backup traveling (self-propelled transportation to a maintenance shop or the like) can be made possible.

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

In this embodiment, the failure diagnosis is performed based on whether or not the valve opening current has reached a predetermined value in the valve opening current diagnosis window. However, the present invention is not limited to this. Instead, the failure diagnosis can be performed based on, for example, a change characteristic (temporal change, inclination, etc.) of the valve opening current. Further, the control for enabling the backup traveling according to the present embodiment is used as the backup control when the high voltage system of the injector drive unit 1 is diagnosed as having failed by the failure diagnosis control other than the failure diagnosis control according to the present embodiment. You can do it. In this embodiment, the high voltage stop signal is transmitted to all the cylinders in the event of an abnormality in order to ensure safety or the like, but the high voltage stop signal is transmitted only to the abnormal cylinder. Is also possible.

[Brief description of the drawings]

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

FIG. 2 is a system configuration diagram according to an embodiment of the present invention.

FIG. 3 is a timing chart illustrating drive control of a fuel injection valve in the embodiment.

FIG. 4 is a timing chart for explaining the behavior of the injector when a high-voltage system is abnormal.

FIG. 5 is a graph comparing the fuel injection amount in a normal state and an abnormal state;

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

FIG. 7 is a timing chart for explaining a diagnostic signal and a high-voltage stop signal in the embodiment.

FIG. 8 is a block diagram for explaining backup control when a high-voltage system is abnormal in the first embodiment;

FIG. 9 is a flowchart (initialization) in the embodiment.

FIG. 10 is a flowchart (self-diagnosis permission control) in the embodiment.

FIG. 11 is a flowchart (self-diagnosis) in the embodiment.

FIG. 12 is a flowchart (restriction process) in the embodiment.

FIG. 13 is a flowchart (fuel injection amount calculation) in the embodiment.

[Explanation of symbols]

 Reference Signs List 1 injector drive unit 2 engine control unit 3 control circuit 4 injector solenoid (fuel injection valve) 5 battery voltage 6 boost circuit 7 current detection circuit (current value detection means) 8 failure diagnosis circuit (diagnosis means, valve opening current diagnosis means) Tr1, Tr2 transistor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 65/00 308 F02M 65/00 308

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 drive control system for a fuel injection valve configured to maintain the holding current value until a fuel injection stop command is input from an engine control unit, wherein the drive control system supplies a valve opening current to the solenoid. When an abnormality occurs, the supply of the valve-opening current to the fuel injection valve is stopped, and the holding current is supplied to open the fuel injection valve. A drive control system for a fuel injection valve, wherein a period from a fuel injection start command to a fuel injection stop command is corrected in consideration of a delay. 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 drive control system for a fuel injection valve configured to maintain the holding current value until a fuel injection stop command is input from an engine control unit, wherein the drive control system supplies a valve opening current to the solenoid. Diagnosing means for diagnosing whether an abnormality has occurred; and when the diagnosing means diagnoses that an abnormality has occurred in a system for providing a valve opening current of a drive control system to the solenoid, a valve opening current is supplied to the fuel injection valve. And the backup control means for applying a holding current to open the fuel injection valve.During the backup control by the backup control means, the valve opening delay due to the valve opening operation by the holding current is reduced. Taking into account, an injection command correcting means for correcting the period from the fuel injection start command to the fuel injection stop command, characterized by comprising Fuel injection valve drive control system. 3. A current value detecting means for detecting a current value given to the solenoid, from a time when the fuel injection start command is inputted to a time when the valve opening current reaches the predetermined value. , Based on the current value characteristics at the time of normal operation and the current value characteristics actually detected by the current value detection means, to determine whether there is an abnormality in the system that supplies the valve opening current of the drive control system to the solenoid. The drive control system for a fuel injection valve according to claim 2, comprising: valve current diagnosis means. 4. The method according to claim 1, wherein the correction of the period from the fuel injection start command to the fuel injection stop command is performed by changing a so-called invalid injection pulse width.
The drive control system for a fuel injection valve according to any one of the above. 5. A fuel injection start command from the fuel injection start command so that a fuel injection amount does not become less than a fuel injection amount capable of backing up when an abnormality occurs in a system for supplying a valve opening current of the drive control system to the solenoid. The drive control system for a fuel injection valve according to any one of claims 1 to 4, wherein a period until an injection stop command is limited to a predetermined time or more. 6. A fuel cut control is performed such that when an abnormality occurs in a system for supplying a valve opening current of the drive control system to the solenoid, an engine rotation speed is limited to a predetermined value or less. Claim 1 to Claim 5
The drive control system for a fuel injection valve according to any one of the above. 7. An engine for switching a combustion mode between a stratified combustion mode and a homogeneous combustion mode, forcibly when an abnormality occurs in a system for providing a valve opening current of a drive control system to the solenoid. The drive control system for a fuel injection valve according to any one of claims 1 to 6, wherein the fuel injection timing is a timing for homogeneous combustion.