JP5637153B2 - Injection abnormality detection device and injector control device - Google Patents

Description

  The present invention relates to an injection abnormality detection device that detects an injection abnormality of an injector control device that controls an on-off valve of an injector, and an injector control device that includes the injection abnormality detection device.

  Conventionally, as a technique related to an injection abnormality detection device for detecting an injection abnormality of an injector control device that controls an on-off valve of an injector that injects fuel into an internal combustion engine, a failure diagnosis device for an automobile engine control device disclosed in Patent Document 1 below It has been known. This fault diagnosis device stops a single injector when the engine is idling while driving a plurality of injectors to a normal state, and when the engine operating condition clearly changes, the stop injector is normal. It is determined that the stop injector is abnormal when the operating condition of the engine does not change.

Japanese Patent Laid-Open No. 02-105034

FIG. 10 is a block diagram showing a schematic configuration of a conventional injection abnormality detection circuit 120 capable of distinguishing between valve closing continuation abnormality and valve opening continuation abnormality. FIG. 11 is a block diagram showing a schematic configuration of a conventional injection abnormality detection circuit 130 that cannot distinguish between a valve closing continuation abnormality and a valve opening continuation abnormality.
By the way, as abnormality regarding an injector control apparatus, there exists valve-closing continuation abnormality which a valve-closing state continues, for example, without a injector switching to a valve-opening state by disconnection etc. When such an abnormality occurs, the amount of fuel to be injected is less than the specified amount, resulting in insufficient torque or rough idle. Further, as an abnormality related to the injector control device, for example, there is a valve opening continuation abnormality in which the valve opening state continues without the injector switching to the valve closing state due to a ground short or the like. When such an abnormality occurs, the fuel to be injected is in an excessive fuel state. The abnormality related to the injector control device includes not only the valve closing continuation abnormality and the valve opening continuation abnormality, but also, for example, an overcurrent abnormality in which a current exceeding a specified value flows to the drive driver or the like.

  An engine control ECU 110 shown in FIG. 10 is an electronic device that drives and controls the injector 100, and includes a driver IC 112 that controls the on-off valve state of the injector 100 and a microcomputer 111 that controls the driver IC 112. The driver IC 112 controls the drive driver 114 connected to the low potential side of the injector 100 by the driver control unit 113 in accordance with the drive signal input from the microcomputer 111. Further, on / off control (switching control) of a high current driver or a constant current driver (not shown) connected to the high potential side of the injector 100 makes constant current control using the power supply voltage of the battery B with respect to the injector 100. Etc. can also be implemented.

  For the driver IC 112 configured as described above, in order to detect an abnormality such as a valve closing continuation abnormality and a valve opening continuation abnormality, for example, the injection abnormality detection circuit 120 illustrated in FIG. 10 is required. The injection abnormality detection circuit 120 includes a constant current source 121 for determining a valve closing continuation abnormality detection level for distinguishing from a valve opening continuation abnormality, a high threshold comparator 122 for detecting valve continuation abnormality, and valve opening continuation abnormality detection. And a low threshold comparator 123 for use. With such a configuration, the valve closing continuation abnormality and the valve opening continuation abnormality are distinguished and detected according to the outputs from both the comparators 122 and 123.

  By the way, due to a recent cost reduction request, the injection abnormality detection circuit 130 is configured to have the low threshold comparator 123 by eliminating the constant current source 121 and the high threshold comparator 122 as illustrated in FIG. Can do. When configured in this way, it is possible to detect that a fuel system abnormality has occurred in the engine control ECU 110 in accordance with the output from the low threshold comparator 123.

  However, even if it is possible to detect that a fuel system abnormality has occurred, the injection abnormality detection circuit 130 that has achieved cost reduction distinguishes whether this fuel system abnormality is a valve closing continuation abnormality or a valve opening continuation abnormality. Can not do it. Since the valve opening continuation abnormality is an abnormality that leads to an excessive fuel condition, it is a highly urgent abnormality to perform fail-safe against the valve closing continuation abnormality that reduces the fuel supply amount. Even so, it is desirable to be able to distinguish between the valve closing continuation abnormality and the valve opening continuation abnormality.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an abnormality detection device and an injector control device capable of detecting an injection abnormality of the injector control device with a simple configuration. There is.

In order to achieve the above object, the invention according to claim 1 of the present invention is an injector (1-4) for switching between a valve open state in which fuel is injected into an internal combustion engine and a valve closed state in which fuel injection is stopped. On the other hand, an injection abnormality detecting device (30) for detecting an injection abnormality of the injector control device (10) for controlling the on-off valve of the injector by performing constant current control according to on / off control of the switch means (14). Comparing means (21) for comparing the voltage on the low potential side of the injector, which changes according to the on / off control of the switch means, with a reference value, and injection abnormality based on the comparison result of the comparing means. A determination means (11) for determining whether or not the exhaust gas is detected, and detecting either a lean abnormality in which the lean state continues or a rich abnormality in which the rich state continues based on the air-fuel ratio of the exhaust gas And air-fuel ratio abnormality detecting means (11), wherein when the said air-fuel ratio abnormality detecting means after the injection abnormality is determined to have occurred the lean abnormality is detected by the determination unit, the injector is in the open state The rich abnormality is detected by the air-fuel ratio abnormality detecting means after detecting that the injection abnormality is occurring by the determining means after detecting that the valve closing continuation abnormal state is maintained without switching. Once detected, provided with, an abnormal state detecting means (11) for detecting that said injector is an open continuous abnormal state where the opened state is continued without switching to a closed state, said switch means and said comparing means, in the driver IC (12), said determining means, said air-fuel ratio abnormality detecting means and said abnormality detecting means, characterized in that included in the microcomputer (11) To.
In addition, the code | symbol in the parenthesis of a claim and the said means shows a corresponding relationship with the specific means as described in embodiment mentioned later.

In the first aspect of the invention, when the lean abnormality is detected by the air-fuel ratio abnormality detecting means after it is determined by the determining means that the injection abnormality has occurred, the abnormal state detecting means determines that the valve is continuously closed abnormally. Detected. Further, when the rich abnormality is detected by the air-fuel ratio abnormality detection means after the determination means determines that the injection abnormality has occurred, the abnormal state detection means detects that the valve opening continuation abnormal state.

  When a lean abnormality is detected due to the occurrence of an injection abnormality, it is assumed that the fuel to be injected is less than the specified amount, that is, a state in which a valve closing continuation abnormality in which the valve closing state continues continues to occur. Is done. For this reason, when the injection abnormality has occurred and the lean abnormality is detected, the valve closing continuation abnormality can be detected. Further, when a rich abnormality is detected due to the occurrence of an injection abnormality, an excessive fuel state in which the amount of fuel to be injected exceeds a specified amount, that is, a valve opening continuation abnormality in which the valve opening state continues is generated. A state is assumed. For this reason, a valve opening continuation abnormality can be detected when an injection abnormality has occurred and a rich abnormality is detected.

In particular, since the comparison means may be configured to have a function of comparing with a reference value, such as a comparator, the comparison means can be configured with a simple element or the like. In addition, since the sensor for detecting the air-fuel ratio is normally employed in an internal combustion engine that injects fuel injected by the injector, a new result can be obtained by using the detection result from the sensor in the air-fuel ratio abnormality detecting means. There is no need to provide a sensor or the like.
Therefore, the injection abnormality of the injector control device can be detected with a simple configuration.

  In the second aspect of the invention, when the lean state is continuously detected even after the fuel injection amount is increased by the fuel injection amount adjusting means when the continuation of the lean state is detected, the lean ratio is detected by the air-fuel ratio abnormality detecting means. An abnormality is detected. If the fuel injection amount is increased when no valve-continuation abnormality has occurred, the lean state is easily shifted to the rich state. Therefore, if the lean state is detected continuously even when the fuel injection amount is increased in this way, the lean abnormality has occurred due to the valve closing continuation abnormality with a high probability, so the valve closing continuation abnormality is surely confirmed. Can be detected.

  On the other hand, when the rich state is detected continuously after the fuel injection amount is reduced by the fuel injection amount adjusting means when the continuation of the rich state is detected, the rich abnormality is detected by the air-fuel ratio abnormality detecting means. . If the fuel injection amount is reduced when the valve opening continuation abnormality has not occurred, it becomes easier to shift from the rich state to the lean state. Therefore, if the rich state is detected continuously even when the fuel injection amount is reduced in this way, a rich abnormality has occurred with a high probability due to the valve opening continuation abnormality. Can be detected.

  In the invention of claim 3, when the abnormal state detecting means detects any one of the valve closing continuation abnormal state and the valve opening continuation abnormal state, the notification means notifies that fact. As a result, the driver and the like can accurately grasp the abnormal state even if either the abnormal valve-continuation abnormal state or the abnormal valve-continuation abnormal state occurs, and the abnormality can be resolved for the driver or the like. It is possible to prompt appropriate treatment to do.

  According to a fourth aspect of the present invention, there is provided an injector control device comprising the injection abnormality detecting device according to any one of the first to third aspects, the switch means, and a control means for controlling the switch means. Then, the fail-safe when the abnormal valve-opening state is detected by the injection abnormality detection device is implemented to be more urgent than the fail-safe when the abnormal valve-continuation abnormal state is detected.

  Thus, by using the injection abnormality detection device that is simply configured as described above, it is possible to distinguish and detect whether the fuel system abnormality is the valve closing continuation abnormality or the valve opening continuation abnormality. Fail safe according to sex can be implemented.

It is a block diagram which shows schematic structure of the injector control apparatus which employ | adopts the injection abnormality detection apparatus which concerns on 1st Embodiment. FIG. 2 is a block diagram illustrating a schematic configuration of a driver IC in FIG. 1. It is a graph which shows the relationship between the output voltage of an O2 sensor, a lean state, and a rich state. It is a graph which shows the relationship between the saturation current of an A / F sensor, a lean state, and a rich state. It is a flowchart which shows the flow of the injection abnormality detection process in 1st Embodiment. FIG. 6A is a waveform diagram showing the air-fuel ratio detected by the exhaust sensor in the normal state, and FIG. 6B shows a lean state determined according to the detection state shown in FIG. It is a wave form diagram which shows a rich state. FIG. 7A is a waveform diagram showing the air-fuel ratio detected by the exhaust sensor at the time of rich abnormality, and FIG. 7B is a lean state determined according to the detection state shown in FIG. It is a wave form diagram which shows a rich state. It is a flowchart which shows the flow of the injection abnormality detection process in 2nd Embodiment. FIG. 9A is a waveform diagram showing the air-fuel ratio detected by the exhaust sensor at the time of rich abnormality, and FIG. 9B is a lean state determined according to the detection state shown in FIG. FIG. 9C is a waveform diagram showing an increase / decrease in the fuel injection amount adjusted according to the determination result shown in FIG. 9B. It is a block diagram which shows schematic structure of the conventional injection abnormality detection apparatus which can distinguish valve closing continuation abnormality and valve opening continuation abnormality. It is a block diagram which shows schematic structure of the conventional injection abnormality detection apparatus which cannot distinguish valve closing continuation abnormality and valve opening continuation abnormality.

[First Embodiment]
Hereinafter, an abnormality detection device and an injector control device according to a first embodiment of the present invention will be described with reference to the drawings.
An engine control ECU 10 shown in FIG. 1 is mounted on a vehicle, and includes injectors (four in FIG. 1) provided for each of a plurality of cylinders in an internal combustion engine (hereinafter simply referred to as an engine) such as a gasoline engine or a diesel engine. This is an injector control device that individually controls the drive of injectors 1 to 4. The engine control ECU 10 opens and closes the injector according to the energization state (energization time) to the actuator of the injector (a solenoid coil or a piezo element, here employing a solenoid coil, not shown), and the amount of fuel injected into the engine To control.

  The injector is, for example, a direct injection type injector that directly injects fuel into a cylinder. In the case of a four-cylinder engine, four injectors 1 to 4 are provided as illustrated in FIG. Note that the direct injection type injector indicates an injector that directly injects fuel into a cylinder of an engine.

  When the injectors 1 to 4 are energized to the solenoid coil, the valve body is moved to the valve opening position by the solenoid coil. As a result, the injectors 1 to 4 are opened, and the fuel can be injected. Further, in the injectors 1 to 4, when energization to the solenoid coil is stopped (cut off), the valve body is moved to the valve closing position by the solenoid coil. As a result, the injectors 1 to 4 are closed, and fuel injection is stopped.

  FIG. 2 is a block diagram showing a schematic configuration of the driver IC 12 of FIG. In FIG. 2, for the sake of convenience, the injector 1 and elements for driving the injector 1 are illustrated, and illustrations of the injectors 2 to 4 and elements for driving the injectors 2 to 4 are omitted. Yes. Therefore, in the following description, the case where the injector 1 is driven and controlled will be mainly described as an example.

  As shown in FIGS. 1 and 2, the engine control ECU 10 mainly includes a microcomputer 11, a driver IC 12, and an abnormality detection circuit 20. The abnormality detection circuit 20 and the microcomputer 11 are characteristic of the present invention. The injection abnormality detection apparatus 30 which is a structure is comprised. Note that the microcomputer 11 and the driver IC 12 are communicably connected by parallel connection or serial connection.

  The microcomputer 11 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an oscillation circuit, and a nonvolatile memory capable of rewriting stored contents (for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory)). Or a flash ROM). The microcomputer 11 executes a drive control process, an injection abnormality detection process, and the like, which will be described later, by the CPU reading a program stored in the ROM in advance and executing a calculation process.

  The microcomputer 11 is set for each cylinder by executing drive control processing based on engine operation information detected by various sensors (not shown) such as engine speed, accelerator opening, and engine water temperature. A drive signal that is a pulse signal having a pulse width corresponding to the ejection setting period is generated and output to the driver IC 12.

  Thus, while the drive signal is output, the solenoid coil of the injector 1 is energized. That is, the microcomputer 11 sets an energization period for the solenoid coil of the injector 1 based on the engine operation information, and outputs a drive signal (pulse signal) corresponding to the set energization period. That is, the drive signal is equivalent to the energization period in which the pulse duration (pulse width) is set, and can be rephrased as a signal indicating the energization period to the injector 1.

FIG. 3 is a graph showing the relationship between the output voltage of the O2 sensor, the lean state, and the rich state. FIG. 4 is a graph showing the relationship between the saturation current of the A / F sensor, the lean state, and the rich state.
The microcomputer 11 can detect the exhaust gas after the fuel injected from each of the injectors 1 to 4 is burned, and the exhaust sensor 5 that detects the air-fuel ratio that is the ratio of air to fuel can output the detection result. It is connected to the. In the present embodiment, for example, an O2 sensor is employed as the exhaust sensor 5, and the exhaust sensor 5 has an output voltage based on the reference voltage according to the air-fuel ratio of the exhaust gas, as illustrated in FIG. Configured to change. Therefore, the microcomputer 11 detects whether the fuel ratio is in a lean state or the fuel ratio is in a rich state based on the output voltage from the exhaust sensor 5. The exhaust sensor 5 is not limited to the O2 sensor, and may be an A / F sensor in which the saturation current changes linearly according to the air-fuel ratio, as illustrated in FIG. 4, for example. .

  The driver IC 12 performs on / off control of the drive driver 14 connected to the low potential side of the injector 1 by the driver control unit 13 in accordance with the drive signal input from the microcomputer 11. Furthermore, the power supply voltage of the battery B with respect to the injector 1 is utilized by performing on / off control (switching control) of a high current drive driver or a constant current drive driver (not shown) connected to the high potential side of the injector 1. Constant current control or the like can also be performed. In this case, a drive driver is connected to each of the injectors 2 to 4 on the low potential side, and this drive driver is on / off controlled by the driver control unit and connected to the high potential side of each of the injectors 2 to 4. On / off control (switching control) of a high-current drive driver or a constant-current drive driver (not shown) is performed, and constant current control using the power supply voltage of the battery B for each of the injectors 2 to 4 is performed. . Each drive driver is constituted by a switching element such as a MOSFET, for example, and can correspond to an example of “switch means” described in the claims. The driver control unit 13 may correspond to an example of a “control unit” described in the claims.

  The abnormality detection circuit 20 includes a comparator 21 for each of the injectors 1 to 4, and the comparator 21 functions as a comparison unit that compares the low-potential-side voltage of the target injector with a reference value. When the voltage on the low potential side becomes lower than the reference value, a fuel system abnormality signal indicating Lo abnormality is output to the microcomputer 11. Further, when the drive driver 14 is in an overheated state or when an overcurrent flows, a fuel system abnormality signal indicating a Hi abnormality is output to the microcomputer 11. The comparator 21 may correspond to an example of “comparison means” described in the claims.

  Next, an injection abnormality detection process performed by the microcomputer 11 based on the fuel system abnormality signal from the abnormality detection circuit 20 will be described in detail with reference to FIGS. FIG. 5 is a flowchart showing the flow of the injection abnormality detection process in the first embodiment. 6A is a waveform diagram showing the air-fuel ratio detected by the exhaust sensor 5 in a normal state, and FIG. 6B is a lean state determined in accordance with the detection state shown in FIG. It is a wave form diagram which shows a rich state. FIG. 7A is a waveform diagram showing the air-fuel ratio detected by the exhaust sensor 5 at the time of rich abnormality, and FIG. 7B is a lean state determined according to the detection state shown in FIG. It is a wave form diagram which shows a state and a rich state.

  When the injection abnormality detection process is started by the microcomputer 11, first, the determination of No is made in steps S101 and S103 until the above-described Lo abnormality fuel system abnormality signal or Hi abnormality fuel system abnormality signal is input. Repeatedly, when a fuel system abnormality signal indicating Lo abnormality is input from any of the comparators 21 provided for each injector (Yes in S101), it is determined that the fuel system is in an abnormal state, and the fuel system abnormal state is determined. Is set (S105). Note that the microcomputer 11 that performs the determination process shown in step S101 may correspond to an example of a “determination unit” recited in the claims.

  Subsequently, in the determination process shown in step S107, it is determined based on the output from the exhaust sensor 5 whether or not there is a rich abnormality. Note that the microcomputer 11 that performs the determination processing shown in step S107 may correspond to an example of “air-fuel ratio abnormality detection means” and “abnormal state detection means” recited in the claims.

  Here, the rich abnormality and the lean abnormality will be described with reference to FIGS. As shown in FIG. 6A, the air-fuel ratio under normal conditions is such that the exhaust sensor 5 alternately repeats the low fuel ratio state and the high fuel ratio state based on the optimal fuel ratio state. Detected. In this case, as shown in FIG. 6B, it is determined that a lean state with a low fuel ratio and a rich state with a high fuel ratio appear alternately.

  On the other hand, as shown in FIG. 7A, when a high fuel ratio is continuously detected, the rich state is continuously detected without detecting the lean state, as shown in FIG. 7B. Is determined to be rich abnormality. Further, when the state where the fuel ratio is low is continuously detected, the detection of the lean state is continued without detecting the rich state, and it is determined that the lean is abnormal.

  When the rich abnormality as illustrated in FIG. 7 is detected based on the output from the exhaust sensor 5 in the determination process shown in step S107 (Yes in S107), the valve opening continuation abnormality state is caused for the following reason. It is confirmed that there is a flag, and a flag indicating the confirmation of the valve opening continuation abnormal state is set (S109).

  When a rich abnormality is detected due to the occurrence of an injection abnormality, an excessive fuel state in which the amount of fuel to be injected exceeds the specified amount, i.e., the valve opening state continues without the injector switching to the valve closing state. The state where the valve opening continuation abnormality will occur is assumed. For this reason, a valve opening continuation abnormality can be detected when an injection abnormality has occurred and a rich abnormality is detected.

  Thus, when the valve-opening continuation abnormal state is determined, the first fail-safe process shown in step S111 is performed. In this process, a measure for eliminating the valve opening continuation abnormality is performed. Specifically, for example, a warning lamp 31 provided on an instrument panel or the like is turned on in a predetermined state to notify the occurrence of valve opening continuation abnormality and to urge the stop of the vehicle operation, and stop the fuel supply after the operation is stopped. As a result, it is possible to reliably prevent the occurrence of an excessive fuel state caused by the valve opening continuation abnormality, which is an abnormality that is highly urgent to implement failsafe.

  On the other hand, if a lean abnormality is detected in the determination process shown in step S107 based on the output from the exhaust sensor 5 (No in S107), it is determined that the valve-closing continuation abnormal state is present for the following reason. Thus, a flag indicating the confirmation of the valve-continuation abnormal state is set (S113).

  When the lean abnormality is detected due to the occurrence of the injection abnormality, the fuel to be injected is less than the prescribed amount, that is, the valve closing state continues without the injector switching to the valve opening state. It is assumed that the valve closing continuation abnormality occurs. For this reason, when the injection abnormality has occurred and the lean abnormality is detected, the valve closing continuation abnormality can be detected.

  Thus, when the valve closing continuation abnormal state is determined, the second fail-safe process shown in step S115 is performed. In this process, measures are taken to eliminate the valve closing continuation abnormality. Specifically, for example, the warning lamp 31 is lit in a predetermined state to notify the occurrence of the valve closing continuation abnormality, and the engine speed is controlled so that the engine speed does not exceed a predetermined upper limit value. Thus, the load on the engine is reduced to prevent a state of torque shortage or rough idling. Thereby, even when a valve closing continuation abnormality that is an abnormality that is less urgent to perform fail-safe than when a valve opening continuation abnormality occurs occurs, it is possible to perform a treatment suitable for the abnormal state.

  In addition, since the drive driver 14 is overheated or an overcurrent flows, when a fuel abnormality signal indicating an abnormality in Hi is input (Yes in S103), it is determined that the fuel system is abnormal, and the fuel system A flag indicating the confirmation of the abnormal state is set (S117). Such an abnormality is an abnormality that is less urgent to perform fail-safe than when the valve-opening continuation abnormality occurs, as in the case of the valve-closing continuation abnormality. Therefore, the second fail-safe process shown in step S115 is performed. Thus, the warning lamp 31 is lit in a predetermined state, and the rotational speed suppression control is performed.

  As described above, in the injection abnormality detection device 30 according to the present embodiment, the lean abnormality is detected when it is determined that an injection abnormality has occurred due to the input of the Lo abnormality fuel system abnormality signal from the comparator 21. Then, it is detected that the valve closing continuation abnormal state is present. Further, if it is determined that an injection abnormality has occurred due to the input of a Lo abnormality fuel system abnormality signal, a rich abnormality is detected, and it is detected that the valve opening continuation abnormality state is present.

Since the comparison means for comparing the low potential side voltages of the injectors 1 to 4 with the reference value may be configured to have a function of comparing with the reference value as in the comparator 21, the comparison means may be a simple element or the like. Can be configured. Further, since the exhaust sensor 5 for detecting the air-fuel ratio is normally employed in an internal combustion engine that injects the fuel injected by the injectors 1 to 4, a new result can be obtained by using the detection result from the exhaust sensor 5. There is no need to provide a sensor or the like.
Therefore, an injection abnormality of the engine control ECU 10 (injector control device) such as the driver IC 12 can be detected with a simple configuration.

  And the fail safe when the valve opening continuation abnormal state is detected by the injection abnormality detection device 30 is implemented so as to be more urgent than the fail safe when the valve closing continuation abnormal state is detected. Thereby, by using the injection abnormality detection device 30 configured simply as described above, it is possible to distinguish and detect whether the fuel system abnormality is the valve closing continuation abnormality or the valve opening continuation abnormality. Fail safe according to the urgency can be implemented.

  Further, in the first fail-safe process and the second fail-safe process described above, when either the valve closing continuation abnormal state or the valve opening continuation abnormal state is detected, this is notified by the lighting of the warning lamp 31. As a result, the driver can accurately grasp the abnormal state even when either the abnormal valve-continuation abnormal state or the abnormal valve-continuation abnormal state occurs, and not only performs fail-safe operation, It is possible to prompt a person or the like to take appropriate measures to eliminate the abnormality. In addition, you may alert | report the said abnormality not only with the warning lamp 31 but with the warning device etc. which can alert | report visually or auditorily. The warning lamp 31 and the warning device may correspond to an example of “notification means” described in the claims.

[Second Embodiment]
Next, an abnormality detection device and an injector control device according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a flowchart showing the flow of the injection abnormality detection process in the second embodiment. FIG. 9A is a waveform diagram showing the air-fuel ratio detected by the exhaust sensor at the time of rich abnormality, and FIG. 9B is a lean state determined according to the detection state shown in FIG. FIG. 9C is a waveform diagram showing an increase / decrease in the fuel injection amount adjusted according to the determination result shown in FIG. 9B.

  In the second embodiment, in order to reliably detect the valve closing continuation abnormality and the valve opening continuation abnormality, the injection abnormality detection process is performed based on the flowchart shown in FIG. 8 instead of the flowchart shown in FIG. Different from the abnormality detection apparatus of the first embodiment. Therefore, substantially the same components as those of the abnormality detection device of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the injection abnormality detection process according to the second embodiment, as can be seen from the flowchart shown in FIG. 8, a flag indicating the confirmation of the fuel system abnormal state when the Lo abnormality fuel system abnormality signal is input (Yes in S101). Is set (S105), the fuel injection amount adjustment process shown in step S106 is performed. In this process, based on the output from the exhaust sensor 5, for example, as illustrated in FIGS. 9A and 9B, when continuation of the rich state is detected, it is illustrated in FIG. 9C. In addition, the fuel injection amount is reduced. Further, when the continuation of the lean state is detected, the fuel injection amount is increased. Here, the fuel injection amount is adjusted by the driver IC 12 controlling the supply current to the injector to adjust the opening of the injector. The driver IC 12 may correspond to an example of “fuel injection amount adjusting means” recited in the claims.

  Then, in the state where the fuel injection amount is adjusted as described above, the determination process shown in step S107 is performed, and it is determined based on the output from the exhaust sensor 5 whether or not there is a rich abnormality. Specifically, when the rich state is continuously detected after a predetermined time (for example, 1 s) has elapsed by decreasing the fuel injection amount when the continuation of the rich state is detected (the dashed line region S in FIG. 9). See) and a rich abnormality is detected. Further, when the lean state is detected and the fuel injection amount is increased and the lean state is continuously detected after a predetermined time has elapsed, a lean abnormality is detected.

  If the fuel injection amount is reduced when the valve opening continuation abnormality has not occurred, it becomes easier to shift from the rich state to the lean state. Therefore, if the rich state is detected continuously even when the fuel injection amount is reduced in this way, a rich abnormality has occurred with a high probability due to the valve opening continuation abnormality. Can be detected.

  Further, if the fuel injection amount is increased when the valve closing continuation abnormality has not occurred, it becomes easier to shift from the lean state to the rich state. Therefore, if the lean state is detected continuously even when the fuel injection amount is increased in this way, the lean abnormality has occurred due to the valve closing continuation abnormality with a high probability, so the valve closing continuation abnormality is surely confirmed. Can be detected.

In addition, this invention is not limited to said each embodiment, You may actualize as follows.
(1) The engine control ECU 10 is not limited to driving and controlling the four injectors 1 to 4. For example, the engine control ECU 10 may be configured to have one to three injectors as driving control, or may have five or more injectors as driving control. It may be configured. In this case, the comparator 21 is provided for each injector so as to compare the voltage on the low potential side of the target injector with the reference value.

(2) In the first fail-safe process described above, it is not limited to stopping the fuel supply after stopping the operation by detecting the valve opening continuation abnormality, and should respond to an excessive fuel state Treatment may be performed. Further, in the second fail-safe process, not only the rotation speed suppression control is performed by detecting the valve closing continuation abnormality, but also a measure that should be taken in response to a state in which the fuel to be injected is less than the specified amount is performed. May be. Thus, fail-safe according to the abnormality can be implemented by distinguishing and detecting the valve opening continuation abnormality or the valve closing continuation abnormality.

DESCRIPTION OF SYMBOLS 1-4 ... Injector 5 ... Exhaust sensor 10 ... Engine control ECU (injector control apparatus)
11 ... Microcomputer (determination means, air-fuel ratio abnormality detection means, abnormal state detection means)
12. Driver IC (fuel injection amount adjusting means)
13 ... Driver control unit (control means) 14 ... Drive driver (switch means)
20 ... Abnormality detection circuit 21 ... Comparator (comparison means)
30 ... Abnormality detection device 31 ... Warning light (notification means)

Claims (4)

Constant current control according to on / off control of the switch means (14) is performed on the injectors (1 to 4) for switching between a valve open state in which fuel is injected into the internal combustion engine and a valve closed state in which fuel injection is stopped. An injection abnormality detecting device (30) for detecting an injection abnormality of the injector control device (10) for controlling the on-off valve of the injector,
Comparing means (21) for comparing a voltage on the low potential side of the injector, which changes in accordance with on / off control of the switch means, with a reference value;
Determination means (11) for determining whether or not an injection abnormality has occurred based on a comparison result of the comparison means;
An air-fuel ratio abnormality detecting means (11) for detecting either a lean abnormality in which the lean state continues or a rich abnormality in which the rich state continues based on the air-fuel ratio of the exhaust gas;
When the lean abnormality is detected by the air-fuel ratio abnormality detection means after the determination means determines that the injection abnormality has occurred, the valve closing state is continued without switching the injector to the valve opening state. When the rich abnormality is detected by the air-fuel ratio abnormality detecting means after detecting that the injection abnormality has occurred after detecting that the valve closing continuation abnormal state has occurred, the injector is closed. An abnormal state detecting means (11) for detecting that the valve opening state is an abnormal state in which the valve opening state is continued without switching to a state;
Equipped with a,
The switch means and the comparison means are included in a driver IC (12),
The determination apparatus, the air-fuel ratio abnormality detecting means, and the abnormal state detecting means are included in a microcomputer (11) . A fuel injection amount adjusting means (12) capable of adjusting a fuel injection amount via the injector;
The air-fuel ratio abnormality detecting means detects the lean abnormality when a lean state is detected continuously after the fuel injection amount is increased by the fuel injection amount adjusting means when continuation of the lean state is detected. When the rich state is detected, the rich abnormality is detected when the rich state is continuously detected even after the fuel injection amount is reduced by the fuel injection amount adjusting means. The injection abnormality detection device according to claim 1.   3. The system according to claim 1, further comprising an informing unit that informs the user when any one of the abnormal continuation valve closing state and the abnormal continuation valve opening state is detected by the abnormal state detection unit. The injection abnormality detection apparatus as described. Injector control comprising: the injection abnormality detecting device according to any one of claims 1 to 3, the switch means, and a control means (13) for controlling the switch means, wherein the on-off valve of the injector is controlled. A device (10) comprising:
The fail-safe when the valve-opening continuation abnormal state is detected by the injection abnormality detecting device is implemented so as to be more urgent than the fail-safe when the valve-closing continuation abnormal state is detected. Injector control device.

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