JP5594251B2 - Fuel injection control device and fuel injection control system - Google Patents

Description

  The present invention relates to a fuel injection control device that controls the operation of an injector that injects fuel into an internal combustion engine, and a fuel injection control system.

  Conventionally, for example, an injector (fuel injection valve) used for an internal combustion engine mounted on a vehicle such as a diesel engine or a gasoline direct injection engine for injecting and supplying fuel to each cylinder is an electromagnetic that opens when energized. It is common to use a valve. In order to control the fuel injection by driving such an injector, the fuel injection control unit (ECU) controls the energization period (the energization start timing and the energization time) to the injector. The fuel injection amount is controlled.

  In addition, a fuel injection control device is known that has a microcomputer and a drive circuit, generates a drive signal based on an injection command from the microcomputer, and the drive circuit energizes the injector based on the drive signal. However, there is also known a configuration in which a drive circuit is not provided (a drive circuit is separated). That is, a fuel injection control unit (ECU) and a drive unit (EDU: Electronic Driver Unit) having a drive circuit are configured as separate units, the ECU outputs a drive signal to the EDU, and the EDU is driven from the ECU. The injector is energized based on the signal.

  For such fuel injection control devices of various configurations, whether or not the drive circuit is normally energized from the drive circuit in response to the injection command generated by itself (or to the drive signal), and thus the injector It is required to have a function of monitoring whether or not fuel injection is normally performed and detecting any abnormality.

  For example, Patent Document 1 describes an example of such an abnormality detection method. That is, in the technique described in Patent Document 1, in the configuration in which the ECU and the EDU are separated, the injector is energized with respect to the end timing of the drive signal from the ECU (timing for instructing the end of injection). A function is provided for determining whether or not the timing to be interrupted matches and outputting a fail-safe signal indicating the determination result. Then, the ECU takes in the fail safe signal from the EDU, and determines whether or not an appropriate current is supplied to the injector based on the fail safe signal.

Japanese Patent No. 3596191

  However, the technique described in Patent Document 1 simply inputs to the ECU a determination result as to whether or not the end timing of the drive signal from the ECU matches the energization cut-off timing of the injector. Only the presence / absence determination based on the determination result can be performed. For this reason, for example, it is not possible to determine a more specific abnormality content such as whether fuel injection is started at a normal timing, a normal time injection, or a normal number of injections.

  On the other hand, it is desirable for electronic control devices of automobiles to be able to determine even the above-described specific abnormal contents, and in the future, it is required to detect even more specific abnormal contents from the viewpoint of functional safety. Is expected.

  That is, the various types of abnormalities exemplified above can be caused by malfunctions or abnormalities of various electronic components / electronic circuits or injectors (hereinafter collectively referred to as “electronic components etc.”) that constitute an ECU or EDU (drive circuit). Therefore, more specific abnormality detection that assumes such malfunctions and abnormalities of electronic components and the like will be required in the future.

  The present invention has been made in view of the above problems, and in a fuel injection control device that controls the operation of an injector, when an abnormality occurs in which the injector is not normally driven, the specific contents of the abnormality can be determined. The purpose is to do so.

  The invention according to claim 1, which has been made in order to solve the above-described problem, generates an injection command indicating the injection period for each injection, and a period in which fuel injection is performed and a period in which fuel injection is not performed based on the injection command And generating a pulsed drive signal whose logic level is inverted, and outputting the drive signal to a drive device for driving the injector, thereby driving the injector and injecting fuel to the internal combustion engine. A fuel injection control device configured to cause

  The drive device is configured to cause the injector to open and inject fuel to the internal combustion engine by energizing the injector when the logic level of the input drive signal is a level indicating a period during which fuel injection is performed. In addition, by detecting the current flowing through the injector, it is determined whether or not the injector is energized, and the logic level is inverted between the energized period and the non-energized period. Such a pulsed energization detection signal is output to the fuel injection control device.

Then, the fuel injection control device compares at least one of the injection command generated by itself and a drive signal generated based on the injection command with an energization detection signal input from the drive device with respect to the drive signal. Then, based on the comparison result, there is provided an abnormality determining means for determining whether or not there is at least one of the first to third abnormal states. Among the abnormal states, the first abnormal state is an abnormal state in which fuel injection is not started at a normal timing from the injector with respect to the injection command, and the second abnormal state is fuel injection from the injector with respect to the injection command. Is an abnormal state that is not performed for a normal time, and the third abnormal state is an abnormal state in which fuel injection from the injector is not performed normally for the injection command.
The fuel injection control device includes an injection command generation unit that generates an injection command, and a drive signal generation unit that generates a drive signal based on the injection command generated by the injection command generation unit. The abnormality determining means includes an injection command generated by the injection command generating means, a drive signal generated by the drive signal generating means based on the injection command, and an energization detection signal input from the drive device with respect to the drive signal, A three-way comparison is performed to compare the three, and an abnormality is determined based on the result of the three-way comparison. In addition, if any of the above abnormal states occurs, the abnormal state occurs. The location that causes the failure (hereinafter also referred to as “failure location”) is identified.

In the following description, for convenience of explanation, at least one of the injection command and the drive signal is also referred to as a control side signal.
According to the fuel injection control device configured as described above, an abnormality determination is performed by comparing the control-side signal generated by itself with the energization detection signal input from the drive device with respect to the control-side signal. Even if an abnormality occurs in the fuel injection control device or the drive device (for example, malfunction or abnormality of electronic components or electronic circuits constituting the device) and fuel injection is not performed normally, At least one of the first to third abnormal states can be determined.

Therefore, it is possible to perform appropriate measures (for example, fail-safe processing) according to the abnormality determination result (which abnormal state has occurred).
Further, in the fuel injection control device configured as described above, for example, when the energization detection signal is not normal with respect to the injection command, the drive signal output from the drive signal generating means is not normal. It is expected that there is a high possibility that some abnormality (for example, abnormality in the drive signal generation means) has occurred on the fuel injection control device side. On the other hand, for example, if the energization detection signal from the drive device is not normal even though the drive signal is normally generated with respect to the injection command, the drive device side (drive device, drive device to injector) It is expected that there is a high possibility that some kind of abnormality has occurred in the energization path or the injector).
In other words, by comparing the three of the injection command, the drive signal, and the energization detection signal, it is possible to identify to some extent the fault location that causes the abnormal state in addition to the presence or absence of the abnormal state. For this reason, when an abnormal state occurs, it is possible to quickly perform a procedure for returning to a normal state (for example, replacement of parts at a failed part, repair, etc.).
Here, the three-way comparison by the abnormality determination means may be performed by directly comparing the three of the injection command, the drive signal, and the energization detection signal individually. For example, as described in claim 2 You can also do it.
That is, an exclusive OR output means for calculating an exclusive OR of the drive signal and the energization detection signal and outputting a pulsed exclusive OR signal indicating the calculation result is provided. Then, the abnormality determination means performs the three-way comparison by comparing the exclusive OR signal from the exclusive OR output means with the energization detection signal.
The timing at which the drive signal becomes active level and the timing at which the energization detection signal becomes active level are actually completely dependent on the specific configuration and injector characteristics for generating and outputting the energization detection signal in the drive device. And the timing at which the energization detection signal is at the active level is slightly delayed from the timing at which the drive signal is at the active level. The same applies to the timing at which the energization detection signal is inverted from the active level with respect to the injection end timing indicated by the drive signal at the end of injection.
Therefore, the exclusive OR of both is calculated using the above-described delay between the drive signal and the energization detection signal. If either one of the drive signal or the energization detection signal becomes abnormal, the exclusive OR of both is naturally different from the normal state. Therefore, abnormality determination can be performed based on the exclusive OR signal.
According to the fuel injection control device configured as described above, the abnormality determination means substantially performs the above three-way comparison by comparing the exclusive OR signal and the energization detection signal. The configuration of the abnormality determination unit and the determination processing load can be simplified. In particular, when the abnormality determination means is constituted by, for example, a microcomputer, if the drive signal and the energization detection signal are individually input, an input port is required separately, but the exclusive OR output means as described above If only one input port for the exclusive OR signal is required instead of each input port for these two signals, an increase in the number of input ports used can be suppressed.
Further, the fuel injection control device provided with the exclusive OR output means as described above may be further configured as described in claim 3, for example. That is, a delay means for delaying the energization detection signal input from the driving device by a predetermined signal delay time is provided. The exclusive OR output means performs the three-way comparison by comparing the energization detection signal after being delayed by the delay means with the drive signal.
As described above, the drive signal and the energization detection signal are actually shifted (delayed), but the shift is not intentionally generated, but is caused by the configuration of each device, injector characteristics, etc. Therefore, there are many cases in which the time is very short, and the deviation may not be reflected in the exclusive OR output means (the logical level of the exclusive OR signal does not change).
Therefore, the energization detection signal is intentionally delayed by the delay means, so that a time difference (delay time) from the logical inversion of the drive signal to the logical inversion of the energization detection signal following the drive signal is appropriately secured. By doing so, an exclusive OR signal can be appropriately generated, and as a result, abnormality determination based on the three-way comparison can be reliably performed.
The invention according to claim 4 generates an injection command indicating the injection period for each injection, and based on the injection command, the logic level is inverted between a period during which fuel injection is performed and a period during which fuel injection is not performed. A fuel injection control device configured to generate a pulsed drive signal and output the drive signal to a drive device for driving the injector, thereby driving the injector to inject fuel into the internal combustion engine It is. The drive device is configured to cause the injector to open and inject fuel to the internal combustion engine by energizing the injector when the logic level of the input drive signal is a level indicating a period during which fuel injection is performed. In addition, by detecting the current flowing through the injector, it is determined whether or not the injector is energized, and the logic level is inverted between the energized period and the non-energized period. Such a pulsed energization detection signal is output to the fuel injection control device. Then, the fuel injection control device compares at least one of the injection command generated by itself and the drive signal generated based on the injection command with the energization detection signal input from the drive device with respect to the drive signal. Based on the comparison result, the first abnormal state in which fuel injection is not started from the injector at a normal timing with respect to the injection command, and the second time in which the fuel injection from the injector is not performed in a normal time with respect to the injection command An abnormality determination means for performing an abnormality determination that is a determination of whether or not the abnormality has occurred in at least one of an abnormal state and a third abnormal state in which fuel injection from the injector is not performed normally in response to an injection command. Prepare.
Then, the abnormality determination means makes an abnormality determination based on at least one of the following differences (a) to (c) including at least the pulse number difference (c), and the pulse (c) In the abnormality determination based on the number difference, if the pulse number difference is not 0, it is determined that the state is the third abnormality state.
(A) Timing difference that is the difference between the injection start timing indicated by the injection command or drive signal and the energization start timing indicated by the energization detection signal. (B) Injection time from the start to the end indicated by the injection command or drive signal, and energization. A drive time difference (c) which is a difference between the energization time from the start to the end of the energization indicated by the detection signal. (C) Every time the logic level of the drive signal changes to an active level indicating a period during which fuel injection is performed. The time is defined as one pulse in the drive signal, and every time the logic level of the energization detection signal changes to the active level indicating the period during which the injector is energized, the time that is the active level is the energization detection signal. The number of injection commands or the number of pulses of the drive signal generated during a predetermined judgment period is In the pulse number difference such fuel injection control apparatus configured is the difference between the number of pulses of the detection signal, if successful, each one of the injection, the injection command is generated one, based on the injection command Thus, one pulse of the drive signal is generated, and one pulse of the energization detection signal is generated for the drive signal. Therefore, the difference in the number of pulses should be zero regardless of the length of the determination period. For this reason, whether or not fuel injection has been performed a normal number of times by performing abnormality determination based on whether or not the pulse number difference during the predetermined determination period is zero (in other words, fuel injection with respect to the control side signal). It is possible to appropriately determine whether or not there has been a case where the fuel injection has not been performed, or whether or not an unintentional injection (an erroneous injection) has been performed.
Incidentally, for example, if such an abnormality determination based on the timing difference, whether the fuel injection from the injector is started at a normal timing, i.e. it can be determined whether the first abnormal state. Further, for example, if the abnormality determination based on the driving time difference is performed, it is possible to determine whether or not the fuel injection is performed for a normal time, that is, whether or not the second abnormal state exists .

Here, in a case where the abnormality determination means performs the abnormality determination based on the timing difference (a), more specifically, for example, it can be configured as described in claim 5 . That is, the abnormality determination means performs abnormality determination based on the timing difference, and determines that the first abnormality state is present when the timing difference exceeds a preset timing difference threshold.

  The time difference between the injection start timing indicated by the control-side signal and the timing at which the energization detection signal becomes the active level is usually determined by a specific configuration for generating and outputting a drive signal in the fuel injection control device, and energization in the drive device. It is uniquely determined by the specific configuration for generating and outputting the detection signal, the characteristics of the injector, and the like. Therefore, by appropriately setting a timing difference threshold based on the uniquely determined time difference and making an abnormality determination using the timing difference threshold as a criterion, it is possible to appropriately determine whether fuel injection has started at a normal timing. Judgment can be made.

Further, when the abnormality determination means performs the abnormality determination based on the driving time difference (b), more specifically, for example, it can be configured as described in claim 6 . That is, the abnormality determination means performs an abnormality determination based on the driving time difference, and determines that the second abnormal state is present when the driving time difference is not within a preset time difference allowable range.

  The time difference between the injection time indicated by the control-side signal and the energization time indicated by the energization detection signal is also uniquely determined by each of the above-described specific configurations, injector characteristics, and the like, similar to the time difference of the start timing. Therefore, by setting an appropriate time difference allowable range based on the uniquely determined time difference and making an abnormality determination using the time difference allowable range as a criterion, whether or not fuel injection has been performed for a normal time (in other words, It is possible to appropriately determine whether or not the injection time has increased or decreased from the normal time.

Next, the invention of claim 7 provides the fuel injection control apparatus according to any one of claims 1 to 6, is integrated with the drive device by incorporating a driving device It is configured. Thus, even if it is the structure where a drive device was integrated with the fuel-injection control apparatus, each effect mentioned above can be acquired.

Next, an invention according to claim 8 is a fuel injection control system comprising the fuel injection control device according to any one of claims 1 to 6 and a drive device. is there.
According to the fuel injection control system configured as described above, the fuel injection control device makes the abnormality determination based on the control-side signal generated by itself and the energization detection signal from the drive device. The same effect as item 6 can be obtained.

It is a block diagram showing schematic structure of the fuel-injection control system of 1st Embodiment. It is explanatory drawing for demonstrating the basic operation | movement and abnormality detection method of the fuel-injection control system of 1st Embodiment. It is a flowchart showing the abnormality detection process of 1st Embodiment. It is a block diagram showing schematic structure of the fuel-injection control system of 2nd Embodiment. It is explanatory drawing for demonstrating the basic operation | movement and abnormality detection method of the fuel-injection control system of 2nd Embodiment. It is explanatory drawing for demonstrating the failure mode and failure location detected in 2nd Embodiment. It is a flowchart showing the abnormality detection process of 2nd Embodiment.

Preferred embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
First, FIG. 1 is a configuration diagram showing a schematic configuration of the fuel injection control system of the first embodiment.

  As shown in FIG. 1, the fuel injection control system of this embodiment includes four injectors that inject fuel into each cylinder # 1 to # 4 of a multi-cylinder (in this example, four cylinders) engine mounted on a vehicle. (Electromagnetic valve) 101, 102, 103, 104 are driven. Specifically, by controlling the energization start timing and energization time to the coils 101a, 102a, 103a, 104a of the injectors 101-104, The fuel injection timing and fuel injection amount to each cylinder # 1 to # 4 are controlled.

  The fuel injection control system includes an EDU (drive unit) 100 that energizes the injectors 101 to 104 based on an input drive signal IJT, and outputs the drive signal IJT to the EDU 100 to thereby output the injectors 101 to 104. And an engine ECU 130 for controlling energization of the motor.

  The engine of the present embodiment is a diesel engine, and a so-called common rail system is constructed in which high pressure fuel is accumulated in a common rail (accumulation chamber) and is injected from each injector into each cylinder. This common rail system is controlled by engine ECU 130. Since the common rail system is well known, detailed description and illustration thereof are omitted here.

  In addition, each of the injectors 101 to 104 is constituted by a normally closed electromagnetic valve, and when the coils 101a to 104a are energized, the injectors 101 are opened to perform fuel injection. Further, when the energization to the coils 101a to 104a is interrupted, the valve is closed and fuel injection is stopped.

  Here, in this embodiment, the injectors 101 to 104 for all four cylinders are divided into two groups of two cylinders, and the injectors 101 and 103 of the cylinders # 1 and # 3 are set as the first group, and their coils 101a, One end on the upstream side of 103a is connected to the first common terminal COM1 of EDU 100, and each of the injectors 102 and 104 of cylinders # 2 and # 4 is made into a second group, and one end on the upstream side of those coils 102a and 104a is connected to EDU 100. It is connected to the second common terminal COM2. Each group is composed of injectors that are not driven simultaneously.

  The downstream ends of the coils 101a to 104a are connected to one of cylinder selection transistors (hereinafter referred to as “cylinder selection transistors”) T10, T20, T30, and T40 via terminals INJ1, INJ2, INJ3, and INJ4 of the EDU 100. It is connected to each output terminal. The other output terminals of the cylinder selection transistors T10 to T40 are connected (grounded) to the ground line via current detection resistors R10 and R20 for each group of injectors.

  Therefore, the current (first drive current) flowing through the coils 101a and 103a of the injectors 101 and 103 via the cylinder selection transistors T10 and T30 corresponding to the cylinders # 1 and # 3 is a voltage generated in the current detection resistor R10. The detected current (second drive current) flowing through the coils 102a and 104a of the injectors 102 and 104 via the cylinder selection transistors T20 and T40 corresponding to the cylinders # 2 and # 4 is a voltage generated in the current detection resistor R20. Detected.

  In the following description, the first drive current and the second drive current may be simply referred to as “drive current” unless it is necessary to distinguish between them. In this example, all transistors provided as switching elements in the EDU 100 are MOSFETs.

  In addition to the cylinder selection transistors T10 to T40 and the current detection resistors R10 and R20, the EDU 100 includes constant current control transistors (hereinafter referred to as “constant current transistors”) T11 and T21, and discharge transistors. T12, T22 (hereinafter referred to as “discharge transistor”), four diodes D11, D12, D21, D22, two capacitors (discharge capacitors) C10, C20, and a DC voltage of the in-vehicle battery 10 as a DC power source ( Booster circuit (DC-DC) that boosts the battery voltage (VB (for example, 12V in this example), generates a voltage higher than the battery voltage VB, and charges the capacitors C10 and C20 to a specified charging voltage (for example, 50V). Converter) 50 and drive circuit 1 for controlling each of the transistors and booster circuit 50 0 and are provided.

  Based on the drive signals IJT1 to IJT4 for the cylinders # 1 to # 4 input from the engine ECU, the drive circuit 120 selects the cylinders having the same logic level as the corresponding drive signals to the gates of the cylinder selection transistors T10 to T40. Signals SL1 to SL4 are output. The drive signals IJT1 to IJT4 mean that the coils 101a to 104a of the injectors 101 to 104 are energized (that is, the injectors 101 to 104 are opened) only while the level of the signals is high (H level). have.

  Therefore, for example, while the drive signal IJT1 corresponding to the cylinder # 1 is at the low level (L level), the drive circuit 120 outputs the cylinder selection signal SL1 at the L level to the corresponding cylinder selection transistor T10, and this cylinder selection transistor. While T10 is turned off and the drive signal IJT1 is at the H level, the drive circuit 120 outputs the cylinder selection signal SL1 at the H level to the corresponding cylinder selection transistor T10 to turn on the cylinder selection transistor T10.

  Further, in the EDU 100, the first discharge transistor T12 is provided for discharging from the first capacitor C10 to the first group of coils 101a and 103a connected to the first common terminal COM1. The discharging transistor T22 is provided for discharging from the second capacitor C20 to the second group of coils 102a and 104a connected to the second common terminal COM2.

  Further, in the EDU 100, the first constant current transistor T11 is provided to allow a constant current (holding current) to flow through the first group of coils 101a and 103a, and the cylinder selection transistor T10 corresponding to the cylinder # 1 or When one of the cylinder selection transistors T30 corresponding to cylinder # 3 is turned on and the first constant current transistor T11 is turned on, one of the cylinder selection transistors T10 and T30 is turned on. A current flows through the coil (101a or 103a) connected to the power source line Lp through the backflow preventing diode D11. The diode D12 is a feedback diode for constant current control with respect to the coils 101a and 103a, and the first constant current transistor T11 is turned off from the on state when any of the cylinder selection transistors T10 and T30 is turned on. When this is done, current is returned to the coils 101a and 103a.

  Similarly, the second constant current transistor T21 is provided to allow a constant current (holding current) to flow through the second group of coils 102a and 104a, and the cylinder selection transistor T20 or cylinder # 2 corresponding to the cylinder # 2 is provided. When any one of the cylinder selection transistors T40 corresponding to 4 is turned on and the second constant current transistor T21 is turned on, the cylinder selection transistor T20 is connected to the one turned on. A current flows through the coil (102a or 104a) from the power supply line Lp through the backflow prevention diode D21. The diode D22 is a feedback diode for constant current control with respect to the coils 102a and 104a, and the second constant current transistor T21 is turned from on to off in a state where any one of the cylinder selection transistors T20 and T40 is turned on. When this is done, current is returned to the coils 102a and 104a.

Each of the constant current transistors T11 and T21 is on / off controlled by the drive circuit 120, and the holding current flows through the on / off control.
Further, the drive circuit 120 has a waveform shaping circuit 21 that generates a first energization detection signal INJF1 that is a pulsed signal by shaping the first drive current that is a current that flows through the first group of injectors 101 and 103; And a waveform shaping circuit 22 that generates a second energization detection signal INJF2 that is a pulse-like signal by shaping the waveform of the second drive current that is the current flowing through the injectors 102 and 104 of the second group. In the following description, the first energization detection signal INJF1 and the second energization detection signal INJF2 may be simply referred to as “energization detection signal INJF” unless it is necessary to distinguish between them.

  The drive current input to each of the waveform shaping circuits 21 and 22 has a waveform as illustrated in the third stage of FIG. Therefore, each waveform shaping circuit 21, 22 sets a threshold value for the input waveform to determine whether or not power is supplied, and L level (ON) during energization and H level (OFF) during non-energization. A pulsed energization detection signal INJF is generated (see the fourth stage in FIG. 2). That is, the energization detection signal INJF is at the H level (OFF) when not energized, and after the start of energization, when the drive current exceeds a predetermined ON threshold, the energization detection signal INJF assumes the energized state and becomes the L level (ON). Is a pulse signal that becomes H level (OFF) when it falls below a predetermined OFF threshold (<ON threshold). Then, the energization detection signal INJF generated by each waveform shaping circuit 21, 22 is output to the engine ECU 130.

  The engine ECU 130 includes a CPU 11, an output circuit 12, and two input circuits 13 and 14. The CPU 11 executes various control programs (stored in a memory (not shown)) on the basis of various engine operation information such as the engine speed, the accelerator opening, the engine water temperature, and the rail pressure in the common rail, for example. The injection commands TQ1 to TQ4, which are pulse signals, are generated and output to the output circuit 12 for every ~ # 4.

  The output circuit 12 outputs, for each of the injection commands TQ1 to TQ4 input from the CPU 11, the drive signals IJT1 to IJT4 that are pulse signals corresponding to the injection commands (that change in level at the same timing). And output to the EDU 100 (to the drive circuit 120). In the following description, the injection commands TQ1 to TQ4 and the drive signals IJT1 to IJT4 may be simply referred to as “injection command TQ” and “drive signal IJT”, respectively, unless it is necessary to distinguish them.

  As illustrated in the first stage of FIG. 2, one injection command (TQ) is generated for each injection. That is, the CPU 11 controls the energization start timing (discharge start timing) and the energization time for the coils of the cylinders # 1 to # 4 to set the injectors 101 to 104 in a predetermined sequence for the predetermined period (the energization time). Time) Open the valve. Therefore, when the timing for opening the injector for a certain cylinder (that is, the injection start timing) arrives, the CPU 11 turns on by raising the injection command TQ corresponding to that cylinder to the H level (time t1). Then, when a predetermined injection time has elapsed, the injection command TQ is turned OFF by falling to the L level (time t3).

  In response to this injection command TQ, the output circuit 12 generates a drive signal IJT whose level changes at the same timing as the input injection command TQ, as shown in the second stage of FIG. That is, one (one pulse) drive signal IJT is output to the EDU 100 for each injection. Note that depending on the circuit configuration, the drive signal IJT may cause a slight deviation (delay) with respect to the injection command TQ, but the deviation is negligible. The injection command TQ and the drive signal IJT corresponding thereto are treated as pulse signals that change at the same timing.

  Each of the input circuits 13 and 14 has an interface function for relaying the energization detection signals INJF1 and 2 input from the drive circuit 120 of the EDU 100 and outputting them to the CPU 11, and is leveled at the same timing as the energization detection signal INJF. A changing pulse signal is output to the CPU 11. Therefore, for convenience of explanation, it may be understood that the energization detection signals INJF1 and 2 are input to the CPU 11 via the input circuits 13.

  Thus, the CPU 11 generates the injection command TQ for each injection for each of the cylinders # 1 to # 4, and the output circuit 12 generates the drive signal IJT in response to the injection command TQ. Output to the drive circuit 120.

  On the other hand, when the drive signal IJT corresponding to any cylinder rises to H level (time t1 in FIG. 2), the drive circuit 120 of the EDU 100 responds by setting the cylinder selection signal SL of the corresponding cylinder to H level. The cylinder selection transistor T10 (or T20) to be turned on is turned on, and the corresponding discharge transistor T12 (or T22) is turned on. As a result, the discharge from the corresponding capacitor C10 (or C20) to the injector of the corresponding cylinder is started, and the drive current starts to flow as shown in the third stage of FIG. When the drive current exceeds a predetermined ON threshold after starting the discharge (time t2), the energization detection signal INJF falls from the H level (OFF) to the L level (ON).

  When a certain amount of the drive current flows (for example, when the current value reaches a predetermined current threshold value), the drive circuit 120 turns off the corresponding discharge transistor to stop the discharge from the capacitor, and the corresponding constant current. By performing ON / OFF control of the transistor T11 (or T21), a constant holding current is supplied to the injector to hold the valve open state.

  The driving circuit 120 operates the booster circuit 50 every time discharge from either the first capacitor C10 or the second capacitor C20 is performed until the next discharge is started after the discharge is stopped. Then, the capacitors C10 and C20 are charged, and the capacitors C10 and C20 are charged to a specified charging voltage.

  When the drive signal IJT from the engine ECU 130 falls to the L level (OFF) due to the elapse of a predetermined injection time (energization time), the drive circuit 120 turns on / off the constant current transistor T11 (or T12). The control is stopped and completely turned off, and the corresponding cylinder selection signal SL is set to the L level to stop energization of the injector.

  Thereby, after time t3, the drive current decreases and eventually becomes zero. In the process of the decrease, when the drive current falls below a predetermined OFF threshold (time t4), the energization detection signal INJF rises to the H level (OFF).

  In this way, each time the CPU 11 of the engine ECU 130 generates one injection command TQ (one pulse) for a certain cylinder, one fuel injection is performed by the injector of the corresponding cylinder.

  In the fuel injection control system of the present embodiment configured as described above, the engine ECU 130 further determines whether or not fuel injection has been performed normally, and more specifically, in the case of an abnormal state that is not performed normally. It has an abnormality detection function that detects what kind of abnormal state it is.

  Specifically, the CPU 11 compares the injection command TQ generated by itself with the energization detection signal INJF input from the EDU 100 with respect to the injection command TQ (waveform comparison). Determine the type of abnormal condition.

  One of the three types of abnormal states is an abnormality in the injection start timing. If the fuel injection control system is normal, as shown in FIG. 2, when the CPU 11 outputs (ON) the injection command TQ (time t1), the energization detection signal INJF is also turned ON after a predetermined time from the injection command. (Time t2). The ON timing difference Ts, which is the time difference (t2−t1) from when the injection command TQ is turned on to when the energization detection signal INJF is turned on, is an ON threshold (INJF) when the drive current is waveform-shaped into the energization detection signal INJF. In addition to the filter constant of the RC filter (low-pass filter) provided at the output stage in the waveform shaping circuits 21 and 22, the characteristics of the actuator (injector), and the drive voltage (applied to the injector). It is uniquely determined by various factors such as voltage. In the waveform shown in FIG. 2, the delay due to factors other than the ON threshold among the above-mentioned various factors is omitted for convenience of explanation, but actually, from the time t1 when the injection command TQ rises, The energization detection signal INJF falls at time t2 after being delayed by the factor.

  Therefore, a predetermined time that is somewhat larger than the uniquely determined time difference in normal time is set in advance as a timing difference threshold value for abnormality determination, and based on whether the ON timing difference Ts is within the timing difference threshold value or not. Then, it is determined whether or not the injection start timing is abnormal. That is, if the ON timing difference Ts is larger than the timing difference threshold, it is determined that an abnormality that causes the injection start timing to be delayed from the normal time has occurred.

  The other one of the three types of abnormal states is an abnormal injection time. If the fuel injection control system is normal, as shown in FIG. 2, the time during which the injection command TQ is ON (pulse width of the injection command TQ), that is, the time from when the injection command TQ rises to when it falls again. The difference between a certain ON time T1 and the time when the energization detection signal INJF is ON (the pulse width of the energization detection signal INJF, and the ON time T2 that is the time from falling to rising again) Uniquely determined by factors.

  Therefore, based on the time difference between the ON time T1 (pulse width) of the injection command TQ and the ON time T2 (pulse width) of the energization detection signal INJF, which is uniquely determined at normal time, a predetermined time difference including the time difference is allowed. A range is set in advance. Then, the abnormality in the injection time is determined based on whether or not the time difference between the ON time T1 and the ON time T2 is within the time difference allowable range. That is, if the time difference between the ON time T1 and the ON time T2 is larger than the time difference allowable range, an abnormality such that the injection time increases compared to the normal time (that is, the injection amount increases from the normal time) occurs. If it is smaller, it is determined that an abnormality has occurred in which the injection time is shorter than normal (that is, the injection amount decreases from normal).

  Another of the three types of abnormal states is an abnormality in the number of injections. If the fuel injection system is normal, the number of pulses of the injection command TQ and the number of pulses of the energization detection signal INJF within a predetermined time should be the same. Therefore, a predetermined determination period (for example, a predetermined period in which a plurality of injection commands TQ are generated) is appropriately set, and the number of pulses of the both is compared during the determination period to determine whether or not they are the same (in other words, both Whether or not the difference in the number of pulses is zero) is determined. That is, if the number of pulses of the energization detection signal INJF is larger than the number of pulses of the injection command TQ, it is determined that unintended injection (erroneous injection) has been performed, and conversely, if the number of pulses of the energization detection signal INJF is small It is determined that the fuel was not properly injected (misfire).

  The above-described determination of the presence or absence of three types of abnormal states is realized by the CPU 11 executing an abnormality detection processing program stored in a ROM (not shown). FIG. 3 shows a flowchart of the abnormality detection process.

  In the present embodiment, this abnormality detection process is executed individually for each energization detection signal INJF1, 2 from each input circuit 13, 14 (that is, for each group of the first group and the second group). In addition, each time the injection command TQ is output (that is, every time one pulse is output), each group is sequentially output at a predetermined timing until the next injection command TQ rises. This is executed for the injection command TQ.

  In parallel with this abnormality detection process, a process of cumulatively counting the number of pulses of each of the injection command TQ and the energization detection signal INJF for each cylinder is also executed. Further, the accumulation period for performing the accumulation count can be set as appropriate.

  When the CPU 11 outputs the injection command TQ for any of the cylinders and starts this abnormality detection process for that injection, first, in S110, the number of pulses of the injection command TQ currently accumulated for that cylinder. And whether the number of pulses of the energization detection signal INJF is the same. If they are not the same (S110: NO), it is determined in S160 whether the number of pulses of the injection command TQ is greater than the number of pulses of the energization detection signal INJF.

  If the number of pulses of the injection command TQ is larger (S160: YES), in S170, the injector is not energized with respect to the injection command TQ (that is, fuel injection is not performed) and misfire occurs. For example, after performing predetermined processing such as performing diagnostic recording to that effect, the abnormality detection processing is terminated.

  On the other hand, if the number of pulses of the energization detection signal INJF is larger (S160: NO), it is determined in S180 that erroneous injection (unintentional injection) has occurred, and, for example, diagnostic recording to that effect is performed. After performing the predetermined process, the abnormality detection process is terminated.

  On the other hand, if the number of pulses is the same (S110: YES), the process proceeds to S120, and whether or not the energization detection signal INJF falls (ON) within the timing difference threshold after the injection command TQ rises (ON), that is, , It is determined whether or not the ON timing difference Ts is within the timing difference threshold value. If the energization detection signal does not fall within the timing difference threshold value (S120: NO), it is determined in S130 that the injection timing is abnormal, for example, a diagnosis recording to that effect is performed. After performing the above process, the abnormality detection process is terminated.

  On the other hand, when the energization detection signal falls within the timing difference threshold (S120: YES), the process proceeds to S140, and the pulse width of the injection command TQ (ON time T1) and the pulse width of the energization detection signal INJF (ON time T2). It is determined whether or not the difference is within the time difference allowable range. If it is within the time difference allowable range (S140: YES), this process is terminated as if there was no abnormality. If it is not within the time difference allowable range (S140: NO), the injection is performed at S150. It is determined that an abnormality in which the amount increases or decreases has occurred, and after performing predetermined processing such as performing diagnostic recording to that effect, the abnormality detection processing is terminated.

  Note that the CPU 11 detects the energization detection signal INJF with respect to the injection command TQ, for example, the energization detection signal INJF does not turn on while the injection command TQ is on (INJF turns on after TQ turns off). When the delay is too large, the abnormality detection process is stopped, and diagnostic recording or some kind of alerting to the user (for example, a display for prompting inspection) is performed.

  As described above, in the fuel injection control system of the present embodiment, the CPU 11 of the engine ECU 130 waveforms the injection command TQ generated by itself and the energization detection signal INJF input from the EDU for the injection command TQ. By comparing, it is determined whether or not fuel injection is normally performed. Therefore, in addition to being able to determine the presence or absence of an abnormality, when an abnormality has occurred, it is possible to specifically determine which of the above-mentioned three types of abnormal states is present, and the user can You can know the contents of more specifically. For this reason, when an abnormality occurs, it is possible to quickly and appropriately take measures for eliminating the abnormality.

  The three types of abnormal states are determined by checking whether the number of pulses of the injection command TQ and the energization detection signal INJF is the same, whether the ON timing difference Ts is within the timing difference threshold, and the injection command TQ. The difference between the pulse width of the current detection signal INJF and the pulse width of the energization detection signal INJF is determined based on whether or not the time difference is within an allowable range. It can be done properly and reliably.

  Further, when performing abnormality detection, the EDU 100 simply generates an energization detection signal INJF indicating whether or not the injector is energized and outputs it to the engine ECU 130. The abnormality detection process itself is performed on the engine ECU 130 side. Done. Therefore, it is not necessary to complicate the configuration of the EDU 100 for mounting the abnormality detection function. Therefore, it is possible to provide a fuel injection control system having a high abnormality detection performance with a simple configuration.

[Second Embodiment]
FIG. 4 shows a schematic configuration of the fuel injection control system of the second embodiment. Compared with the fuel injection system of the first embodiment, the fuel injection system of the present embodiment differs in a part of the configuration in the engine ECU and the content of the abnormality detection process, and the other EDUs 100 and the injectors 101 to 104 are different. The configuration is the same as in the first embodiment. Therefore, the description of the same components as those in the first embodiment will be omitted below, and only the components different from those in the first embodiment will be described.

  In the first embodiment, the presence or absence of abnormality is determined by comparing the waveform of the injection command TQ and the energization detection signal INJF. In this embodiment, in addition to these two signals TQ and INJF, the drive signal IJT is also taken into consideration. Then, the presence or absence of abnormality is determined. That is, in the engine ECU 150 of this embodiment, the CPU 31 generates the injection command TQ generated by itself, the drive signal IJT generated and output by the output circuit 32 in response to the injection command TQ, and the EDU 100 for the drive signal IJT. The three are compared (waveform comparison) with the energization detection signal INJF input from (from the drive circuit 120). In addition to determining whether or not there is an abnormal state by the three-way comparison as in the first embodiment, the present embodiment further includes a location (failure) causing the abnormal state. Location) and the specific failure content (failure mode) at that location.

  In order to realize such a high-performance abnormality determination function, the engine ECU 150 of this embodiment includes an OR circuit, a delay circuit, and an EXOR circuit for each group as shown in FIG.

  That is, for the first group, an OR circuit 41 that inputs the drive signals IJT1, 3 corresponding to the first group and outputs a logical sum of them, and an energization detection signal INJF1 corresponding to the first group. Is delayed by a predetermined signal delay time Tdx (see FIG. 5), and an EXOR circuit 43 that calculates an exclusive OR (EXOR) of the output of the OR circuit 41 and the output of the delay circuit 42 is provided. . Then, an EXOR signal that is an output signal from the EXOR circuit 43 is input to the CPU 31.

  The same applies to the second group, and an OR circuit 41 that inputs the drive signals IJT1, 3 corresponding to the first group and outputs a logical sum of the two, and an energization detection signal corresponding to the first group A delay circuit 42 that delays INJF1 by a predetermined signal delay time Tdx (see FIG. 5), and an EXOR circuit 43 that calculates an exclusive OR (EXOR) of the output of the OR circuit 41 and the output of the delay circuit 42 are provided. Yes. Then, an EXOR signal that is an output signal from the EXOR circuit 43 is input to the CPU 31.

  As described in the first embodiment, the energization detection signal INJF is input with a slight delay with respect to the drive signal IJT. Further, as described above, the delay is uniquely determined by various factors such as the filter constant in the drive circuit 120, the characteristics of the injector, and the drive voltage.

  Therefore, in the present embodiment, using the fact that the delay as described above occurs between the drive signal IJT and the energization detection signal INJF, the exclusive OR of both is calculated, and based on the EXOR signal that is the calculation result. Make an abnormality. If either one of the drive signal IJT or the energization detection signal INJF becomes abnormal, the exclusive OR of both naturally becomes different from the normal state, so that it is possible to make an abnormality determination based on the EXOR signal. .

  However, the deviation (delay) between the drive signal IJT and the energization detection signal INJF caused by the various factors described above is not intentionally generated in the design. The EXOR circuit may not be recognized correctly.

  Therefore, in the present embodiment, a delay circuit is provided in the engine ECU 150 to intentionally delay the energization detection signal INJF by the signal delay time Tdx, so that the drive signal IJT and the energization are as shown in the fifth waveform in FIG. A deviation from the detection signal INJF is clearly generated, and an edge change of the EXOR signal is surely generated. Thereby, as shown in the sixth stage (lowermost stage) in FIG. 5, an EXOR signal composed of two pulses is generated for each injection. In FIG. 5, each waveform in the first to fourth stages is exactly the same as each waveform shown in FIG.

  Of the two pulses constituting the EXOR signal, the first pulse is from the time when the injection command TQ rises to H level until the energization detection signal INJF (however, delay circuit output) falls (time t1 in FIG. 5). ˜t3) is a pulse having a pulse width Td1 that becomes an active level (L level). The second pulse is the energization detection signal INJF (output of the delay circuit) after the injection command TQ falls to the L level. This is a pulse having a pulse width Td2 that becomes an active level until it rises (time t4 to t6 in FIG. 5).

  Thus, in the present embodiment, the drive signal IJT and the energization detection signal INJF are not directly input to the CPU 31, but the exclusive OR of both is calculated and the EXOR signal as the calculation result is input. Is done. Therefore, the CPU 31 directly compares the injection command TQ generated by the CPU 31 with the EXOR signal corresponding thereto. However, the EXOR signal reflects changes in the waveforms of the drive signal IJT and the energization detection signal INJF. If an abnormality occurs in any of the waveforms, the abnormality is reflected as a waveform change in the EXOR signal. Therefore, the CPU 31 substantially compares the three of the injection command TQ, the drive signal IJT, and the energization detection signal INJF.

  Next, various abnormality determinations performed by the CPU 31 of the engine ECU 150 will be described. As described above, the CPU 31 performs the abnormality determination by the three-way comparison, but as in the first embodiment, the CPU 31 has a function of determining the occurrence of any of the three abnormal states related to fuel injection. That is, also in this embodiment, it is possible to determine whether there is an abnormality in the injection start timing, an abnormality in the injection time, and an abnormality in the number of injections based on the three-way comparison.

In addition to this, in the present embodiment, determination of 10 types of failure modes (abnormality No. 1 to NO. 10) as shown in FIG.
Among the failure modes shown in FIG. 1 is a failure mode in which the drive signal IJT remains fixed at the H level regardless of the injection command TQ, and therefore the EXOR signal is also fixed at the H level. This abnormality No. When 1 is detected, it is expected that the drive signal IJT is fixed at the H level due to the failure of the output circuit 32 in the engine ECU 150. In this case, since the drive signal IJT is fixed at the H level, the output of the OR circuit is also kept at the H level, so that the EXOR signal remains at the H level even when fuel is injected from other cylinders in the same group. Become. This abnormality No. When 1 is detected, it can be determined that all of the injection start timing, the injection time, and the number of injections are abnormal as the injector operation (fuel injection) state.

  Abnormal No. 2 is a failure mode in which the drive signal IJT remains fixed at the L level regardless of the injection command TQ, and thus the EXOR signal is also fixed at the H level. This abnormality No. When 2 is detected, it is expected that the drive signal IJT is fixed at the L level due to the failure of the output circuit 32 in the engine ECU 150. However, in this case, since the drive signal IJT is fixed at the L level, the edge change of the EXOR signal should normally occur when the drive signal IJT is turned on at the time of fuel injection of other cylinders in the same group. Therefore, when an abnormality in which the EXOR signal becomes constant at the H level is detected, an abnormality NNo. Is determined depending on whether or not the EXOR signal undergoes an edge change during fuel injection of other cylinders in the same group. 1 and abnormal No. 2 can be distinguished. In addition, abnormality No. When 2 is detected, it can be determined that all of the injection start timing, the injection time, and the number of injections are abnormal as the injector operation (fuel injection) state.

  Abnormal No. No. 3 is a failure mode in which the drive signal IJT has a normal rise timing but the fall timing is late with respect to the injection command TQ, so that the EXOR signal also has a late fall of the second pulse. This abnormality No. When 3 is detected, it is expected that the drive signal IJT does not immediately fall due to a failure of the output circuit 32 in the engine ECU 150 even when the injection command TQ falls. In addition, abnormal No. When 3 is detected, it can be determined that the injection time is abnormal (increased) as the state of the injector operation (fuel injection).

  Abnormal No. No. 4, the drive signal IJT is normal with respect to the injection command TQ, but the fall timing is early (earlier than the fall of TQ), so that the EXOR signal also has the fall of the second pulse earlier. This is a failure mode. This abnormality No. When 4 is detected, it is expected that the drive signal IJT falls before the injection command TQ falls due to a failure of the output circuit 32 in the engine ECU 150. In addition, abnormal No. When 4 is detected, it can be determined that the injection time is abnormal (decreased) as the state of operation of the injector (fuel injection).

  Abnormal No. 5 shows that the drive signal IJT is normal with respect to the injection command TQ, but the pulse generation timing is late (that is, the rise timing and the fall timing are both late), so the EXOR signal also has two pulses. This is a failure mode in which the trailing edge of each becomes slow. This abnormality No. When 5 is detected, it is expected that the drive signal IJT normally follows the injection command TQ and the edge does not change due to the failure of the output circuit 32 in the engine ECU 150. In addition, abnormal No. When 5 is detected, it can be determined that the injection start timing is abnormal (slow) as the state of the injector operation (fuel injection).

  Abnormal No. 6-Abnormal No. 10, the engine ECU 150 is normal and the control side signals (injection command TQ and drive signal IJT) are normally generated and output, but some failure or the like has occurred on the EDU 100 side (including the injector). This is a failure mode that is expected to occur.

  Among these, abnormal No. 6, the energization detection signal INJF remains fixed at the H level regardless of the control side signal, and therefore the rising timing of the first pulse of the EXOR signal is delayed (one when the control side signal falls). It is a failure mode. This abnormality No. When 6 is detected, it is expected that the energization detection signal INJF is fixed at the H level due to a failure on the EDU 100 side. This abnormality No. When 6 is detected, there is a possibility that all of the injection start timing, the injection time, and the number of injections are abnormal as the injector operation (fuel injection) state.

  Abnormal No. 7 is a failure in which the energization detection signal INJF remains fixed at the L level regardless of the control side signal, so that the edge change of the EXOR signal is opposite to that in the normal state and the number of pulses is also one. Mode. This abnormality No. When 7 is detected, it is expected that the energization detection signal INJF is fixed at the L level due to a failure on the EDU 100 side. This abnormality No. When 7 is detected, there is a possibility that all of the injection start timing, the injection time, and the number of injections are abnormal as the state of the injector operation (fuel injection).

  Abnormal No. 8 is a failure mode in which the energization detection signal INJF is normal with respect to the control side signal, but the rise timing is late, and therefore the rise of the second pulse of the EXOR signal is also late. This abnormality No. When 8 is detected, it is expected that the energization detection signal INJF does not immediately rise due to a failure on the EDU 100 side even if the control side signal falls. In addition, abnormal No. When 8 is detected, there is a possibility that the injection time is abnormal (increased) as the state of the injector operation (fuel injection).

  Abnormal No. 9 is that the energization detection signal INJF is normal with respect to the control side signal, but the rise timing is early, but the EXOR signal also rises early for the second pulse and the rise is the control side signal. This is a failure mode that occurs immediately after the fall. This abnormality No. When 9 is detected, it is expected that due to a failure on the EDU 100 side, the energization detection signal INJF rises before the control side signal falls. In addition, abnormal No. When 9 is detected, there is a possibility that the injection time is abnormal (decreased) as the state of the injector operation (fuel injection).

  Note that if the second falling of the EXOR signal is early, the abnormal No. 4 cannot be distinguished from the above, but the abnormality No. 4 or abnormal No. 9 can be distinguished. That is, if the second rise of the EXOR signal is immediately after the fall of the control side signal (substantially the same), the abnormality No. 9 can be judged. 4 can be determined.

  Abnormal No. 10 indicates that the energization detection signal INJF is normal with respect to the control side signal, but the pulse generation timing is late (that is, the rise timing and the fall timing are both late), and therefore the EXOR signal is 2 This is a failure mode in which the falling timing of one pulse is normal but the rising timing is delayed. This abnormality No. When 10 is detected, it is expected that due to a failure on the EDU 100 side, the energization detection signal INJF normally follows the control side signal and the edge does not change. In addition, abnormal No. When 5 is detected, it can be determined that the injection start timing is abnormal (slow) as the state of the injector operation (fuel injection).

  Next, the abnormality detection process executed by the CPU 31 in the engine ECU 150 of the present embodiment will be described with reference to the flowchart of FIG. The CPU 31 executes the abnormality detection process shown in FIG. 7 at the same timing as the abnormality detection process of the first embodiment. As in the first embodiment, in parallel with the abnormality detection process, a process of accumulating the number of pulses of each of the injection command TQ and the energization detection signal INJF individually for each cylinder is also executed.

  When starting the abnormality detection process, the CPU 31 first determines in S310 whether or not the number of pulses of the injection command TQ currently accumulated for the cylinder and the number of pulses of the energization detection signal INJF are the same. If not the same (S310: NO), in S320, it is determined whether or not the number of pulses of the injection command TQ is greater than the number of pulses of the energization detection signal INJF.

  If the number of pulses of the injection command TQ is larger (S320: YES), in S330, the injector is not energized with respect to the injection command TQ (that is, fuel injection is not performed) and misfire occurs. The process B is executed, and the abnormality detection process is terminated.

  Here, in this abnormality determination process, when an abnormality is detected, one of processes A, B, and C is executed for each failure mode. Of these, the process A is a process performed for a failure mode in which the fuel may be injected excessively than normal. For example, the operation of the engine is immediately stopped and the engine operation is stopped. The user is informed of the occurrence of a failure that cannot be received together with the failure mode (abnormality No.).

  On the other hand, the process B is a process that is performed for a failure mode in which the fuel injection may be less (or not injected) than normal, and the process C is normal although there is no abnormality in the fuel injection amount. This is a process that is performed for failure modes that may not be injected at the correct timing. For example, any failure that does not allow normal travel while allowing travel to a certain distance below a certain upper speed limit. Is notified to the user together with the failure mode (abnormality No.).

  If it is determined in S320 that the number of pulses of the energization detection signal INJF is larger, it is determined in S340 that erroneous injection (unintentional injection) has occurred, and process A is executed. This abnormality detection process is terminated.

  On the other hand, if the number of pulses is the same (S310: YES), the process proceeds to S350, and it is determined whether or not the falling edge of the EXOR signal is detected after the injection command TQ rises (ON) and then falls again. . At this time, if the fuel injection system is normal, the EXOR signal should fall, and in this case, the process proceeds to S410, but if the falling edge of the EXOR signal is not detected due to some failure (S350: NO) As the failure mode, abnormal No. One of 1, 2, and 7 is expected.

  Therefore, the process further proceeds to S360, and it is determined whether or not the rising edge of the EXOR signal has been detected after the injection command TQ rises. At this time, if the rising edge of the EXOR signal is detected, the EXOR signal is originally at the L level, and it is considered that the EXOR signal has risen to the H level by the TQ rising. That is, it is considered that the edge change of the EXOR signal is reversed from the normal time. Therefore, in this case, in S370, the abnormality No. It is determined that the failure mode No. 7 has occurred, processing A is executed, and the abnormality detection processing is terminated.

  If the rising edge of the EXOR signal is not detected after the injection command TQ rises in S360 (S360: NO), the failure mode is abnormal No. Since either 1 or 2 is conceivable, it is further determined in S380 whether or not the edge of the EXOR signal has changed even when another cylinder is injecting. If there is no change in the edge of the EXOR signal even when the other cylinders are injecting (S380: YES), in S400, an abnormality No. is detected on the engine ECU 150 side. It is determined that one failure mode has occurred, processing A is executed, and this abnormality detection processing is terminated. On the other hand, if there is a change in the edge of the EXOR signal during the injection of the other cylinders (S380: NO), an abnormality No. is detected on the engine ECU 150 side in S390. It is determined that the second failure mode has occurred, processing B is executed, and this abnormality detection processing is terminated.

  Next, in S350, when the falling edge of the EXOR signal is detected after the injection command TQ rises (ON) and before it falls again (S350: YES), the fall of the EXOR signal occurs in S410. It is determined whether or not the edge has occurred within a predetermined first determination time from the rising timing of the injection command TQ.

  If the system is normal, the first falling edge of the EXOR signal should occur almost simultaneously with the rising edge of the injection command TQ. Therefore, a first determination time is set in advance so that it can be appropriately determined whether or not the EXOR signal also falls almost simultaneously with the rise of the injection command TQ. If the EXOR signal does not fall within the first determination time (that is, if the EXOR signal falls after exceeding the first determination time), in S420, an abnormality No. is detected on the engine ECU 150 side. It is determined that the failure mode No. 5 has occurred, the process C is executed, and the abnormality detection process is terminated.

  On the other hand, if the EXOR signal falls within the first determination time after the injection command TQ rises (S410: YES), the process proceeds to S430, and after the injection command TQ rises, the rising edge of the EXOR signal is set to the second determination time. It is determined whether or not it has been detected.

  If the system is normal, the EXOR signal should rise at a timing delayed by Td1 after the first fall, as described in FIG. Therefore, a second determination time is set in advance so that it can be appropriately determined whether or not the EXOR signal rises at such a normal timing. Specifically, for example, a time (Td1 + α) longer than the time Td1 by a predetermined time α may be set as appropriate. If the first rising edge is detected within the second determination time from the first falling of the EXOR signal, the process proceeds to S470.

  On the other hand, when the first rising edge of the EXOR signal is not detected within the second determination time after the rising of the injection command TQ (that is, after the first falling of the EXOR signal) (S430: NO), Abnormal No. Either 6 or 10 is conceivable. Therefore, in this case, it is further determined in S440 whether or not the rising edge of the EXOR signal has been detected before the injection command TQ falls.

  If the EXOR signal rises before the TQ fall (S440: YES), the EXOR signal rises for the time being, but the rise timing is later than the normal timing, so in S460, there is an abnormality on the EDU 100 side. No. It is determined that 10 failure modes have occurred, processing C is executed, and this abnormality detection processing is terminated. Conversely, if the EXOR signal does not rise before the fall of TQ (S440: NO), in S450, an abnormal No. It is determined that the failure mode 6 has occurred, the process B is executed, and the abnormality detection process is terminated.

  In S470, after the injection command TQ falls, it is determined whether the second falling edge of the EXOR signal is detected within the first determination time. If the system is normal, the first second falling edge of the EXOR signal should occur almost simultaneously with the falling of the injection command TQ, in which case the process proceeds to S530, but after a TQ fall due to some failure If the second falling edge of the EXOR signal is not detected within the first determination time (S470: NO), an abnormality No. It is expected to be either 3, 4, or 9.

  Therefore, the process further proceeds to S480, in which it is determined whether or not the second falling edge of the EXOR signal has been detected before the falling of the injection command TQ. Here, if the second falling edge of the EXOR signal is detected after the falling of the TQ (S480: NO), an abnormality No. is detected on the engine ECU 150 side in S490. It is determined that the failure mode No. 3 has occurred, processing A is executed, and this abnormality detection processing is terminated.

  In S480, when the second falling edge of the EXOR signal is detected before the falling of the injection command TQ (S480: YES), the abnormality No. Since either one of 4 and 9 is conceivable, it is further determined in S500 whether or not the second rising edge of the EXOR signal is detected immediately after the falling of the injection command TQ (substantially simultaneously).

  If the second rising edge of the EXOR signal is detected immediately after the injection command TQ falls (S500: YES), an abnormality No. is detected on the EDU 100 side in S510. It is determined that 9 failure modes have occurred, processing B is executed, and the abnormality detection processing is terminated. Conversely, if the second rising edge of the EXOR signal is not detected immediately after the falling of the injection command TQ (S500: NO), an abnormality No. is detected on the engine ECU 150 side in S520. It is determined that the failure mode No. 4 has occurred, processing B is executed, and this abnormality detection processing is terminated.

  In S470, after the injection command TQ falls, if the second falling edge of the EXOR signal is detected within the first determination time, the process proceeds to S530, and after the injection command TQ falls, the EXOR signal 2 It is determined whether or not the first rising edge is detected within the third determination time.

  If the system is normal, as shown in FIG. 5, the second rising edge of the EXOR signal should be detected at a timing delayed by Td2 after the falling of the injection command TQ. Therefore, a third determination time is set in advance so that it can be appropriately determined whether or not the second rising edge of the EXOR signal is detected at such a normal timing. Specifically, for example, a time (Td1 + β) longer than the time Td2 by a predetermined time β may be set as appropriate.

  If the second rising edge of the EXOR signal is detected within the third determination time after the falling of the injection command TQ (S530: YES), this abnormality detection processing is assumed to be normal without any abnormality. Exit.

On the other hand, if the second rising edge of the EXOR signal is not detected within the third determination time after the injection command TQ falls (S530: NO), the abnormal NO. It is determined that the failure mode 8 has occurred, and the process A is executed to complete the abnormality detection process. As described above, in the fuel injection control system of the present embodiment, the CPU 31 of the engine ECU 150 The injection command TQ generated by the engine, the drive signal IJT generated by the output circuit 32 in the engine ECU 150 for the injection command TQ, and the energization detection signal INJF input from the EDU 100 for the drive signal IJT. In addition to determining whether or not fuel injection is performed normally, if the fuel injection cannot be performed normally, the location that is causing the abnormal state (failure Location) and the specific failure content (failure mode) at that location.

  Therefore, when an abnormal state occurs, the user can specifically know the failure mode and the failure location, and promptly and appropriately take measures for returning to the normal state (for example, replacement of parts at the failure location, repair, etc.) Can be done. That is, it is possible to provide a fuel injection control system with higher merchantability and usability for the user.

  In this embodiment, the drive signal IJT and the energization detection signal INJF are not directly taken into the CPU 31, but the exclusive OR of both is calculated by the EXOR circuit, and the EXOR signal as a result of the calculation is taken into the CPU 31. ing. Therefore, the number of ports used by the CPU 31 can be reduced.

  Furthermore, in this embodiment, the energization detection signal INJF from the EDU 100 is not directly input to the EXOR circuit, but is input to the EXOR circuit after being delayed by a predetermined signal delay time Tdx by the delay circuit. Therefore, the edge change (two pulses) of the EXOR signal can be reliably generated in the normal state, and the abnormality can be accurately detected based on the waveform of the normal EXOR signal composed of the two pulses. it can.

[Modification]
Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments, and can take various forms as long as they belong to the technical scope of the present invention. Needless to say.

  For example, in the first embodiment, abnormality detection is performed by comparing the injection command TQ and the energization detection signal INJF. However, if the output circuit 12 is normal, the injection command TQ and the drive signal IJT have the same pulse. Under the assumption that 12 is normal (that is, the drive signal IJT is normal), abnormality detection may be performed by comparing the drive signal IJT with the energization detection signal INJF. However, in such a case, the CPU 11 has to take in both the drive signal IJT and the energization detection signal INJF, and thus requires two input ports. Therefore, in order to suppress an increase in the number of input ports of the CPU 11, it is preferable to perform abnormality detection based on a comparison between the injection command TQ and the energization detection signal INJF as in the first embodiment.

  In the second embodiment, the EXOR circuits 43 and 48 and the OR circuits 41 and 46 are provided in the engine ECU 150. However, the provision of the EXOR circuits 43 and 48 and the OR circuits 41 and 46 is not essential. The EXOR circuits 43 and 48 may be omitted, and the OR circuit output and delay circuit output may be directly input to the CPU 31. For example, the OR circuits 41 and 46 and the EXOR circuits 43 and 48 may be omitted, The drive signal IJT and the delay circuit output may be directly input to the CPU 31, respectively. Further, the delay circuits 42 and 47 are not essential, and these may be omitted and the energization detection signal INJF from the EDU 100 may be directly input to the CPU 31.

  That is, as a result, as long as the abnormality detection based on the three-way comparison of the injection command TQ, the drive signal IJT, and the energization detection signal INJF can be performed in the CPU 31, how to process these three signals respectively to the CPU 31. There is no particular limitation on whether to input.

  Further, in each of the above embodiments, the fuel injection control system having a configuration in which the engine ECU and the EDU are separated is shown. However, it is not essential to separate the engine ECU and the EDU in this way. The present invention can also be applied to an integrated configuration, that is, a configuration in which an EDU is built in the engine ECU.

  In each of the above embodiments, the fuel injection control system that controls the fuel injection of the diesel engine has been described as an example. However, the fact that the control target is an injector of the diesel engine is merely an example.

  DESCRIPTION OF SYMBOLS 10 ... Car-mounted battery, 11, 31 ... CPU, 12, 32 ... Output circuit, 13, 14 ... Input circuit, 21, 22 ... Waveform shaping circuit, 41, 46 ... OR circuit, 42, 47 ... Delay circuit, 43, 48 ... EXOR circuit, 50 ... Booster circuit, 100 ... EDU, 101-104 ... Injector, 101a-104a ... Coil, 120 ... Drive circuit, 130, 150 ... Engine ECU, C10 ... First capacitor, C20 ... Second capacitor , COM1 ... first common terminal, COM2 ... second common terminal, D11, D12, D21, D22 ... diode, Lp ... power line, R10, R20 ... current detection resistor, T10, T20, T30, T40 ... cylinder selection transistor, T11, T21 ... constant current transistors, T12, T22 ... discharge transistors

Claims (8)

An injection command indicating the injection period is generated for each injection, and based on the injection command, a pulsed drive signal is generated so that the logic level is inverted between a period during which fuel injection is performed and a period during which fuel injection is not performed. A fuel injection control device configured to drive the injector to inject fuel into the internal combustion engine by outputting the drive signal to a drive device for driving the injector,
The drive device opens the injector and injects fuel into the internal combustion engine by energizing the injector when the logic level of the input drive signal is a level indicating a period during which fuel injection is performed. And determining whether or not the injector is energized by detecting the current flowing through the injector, and logically determines whether the energization is performed or not. It is configured to output a pulse-shaped energization detection signal whose level is inverted to the fuel injection control device,
The fuel injection control device
At least one of the injection command generated by itself and the drive signal generated based on the injection command is compared with the energization detection signal input from the drive device with respect to the drive signal, and the comparison result Based on a first abnormal state in which fuel injection from the injector is not started at a normal timing with respect to the injection command, and a second abnormality in which fuel injection from the injector is not performed for a normal time with respect to the injection command. An abnormality determination means for performing an abnormality determination that is a determination as to whether or not the occurrence of at least one of a state and a third abnormal state in which fuel injection from the injector is not normally performed with respect to the injection command When,
Injection command generating means for generating the injection command;
Drive signal generation means for generating the drive signal based on the injection command generated by the injection command generation means;
Equipped with a,
The abnormality determination means is inputted from the drive device with respect to the injection command generated by the injection command generation means, the drive signal generated by the drive signal generation means based on the injection command, and the drive signal. When the three-way comparison for comparing the three of the energization detection signal is performed, the abnormality determination is performed based on the result of the three-part comparison, and any of the abnormal states is further generated as the abnormality determination The fuel injection control device is characterized in that the location causing the abnormal state is also identified . The fuel injection control device according to claim 1 ,
An exclusive OR output means for calculating an exclusive OR of the drive signal and the energization detection signal and outputting a pulsed exclusive OR signal indicating the calculation result;
The abnormality determination means performs the three-way comparison by comparing the exclusive OR signal from the exclusive OR output means and the energization detection signal. The fuel injection control device according to claim 2 ,
Delay means for delaying the energization detection signal input from the driving device by a predetermined signal delay time;
The exclusive OR output unit performs the three-way comparison by comparing the energization detection signal after being delayed by the delay unit and the drive signal. An injection command indicating the injection period is generated for each injection, and based on the injection command, a pulsed drive signal is generated so that the logic level is inverted between a period during which fuel injection is performed and a period during which fuel injection is not performed. A fuel injection control device configured to drive the injector to inject fuel into the internal combustion engine by outputting the drive signal to a drive device for driving the injector,
The drive device opens the injector and injects fuel into the internal combustion engine by energizing the injector when the logic level of the input drive signal is a level indicating a period during which fuel injection is performed. And determining whether or not the injector is energized by detecting the current flowing through the injector, and logically determines whether the energization is performed or not. It is configured to output a pulse-shaped energization detection signal whose level is inverted to the fuel injection control device,
The fuel injection control device
At least one of the injection command generated by itself and the drive signal generated based on the injection command is compared with the energization detection signal input from the drive device with respect to the drive signal, and the comparison result Based on a first abnormal state in which fuel injection from the injector is not started at a normal timing with respect to the injection command, and a second abnormality in which fuel injection from the injector is not performed for a normal time with respect to the injection command. An abnormality determination means for performing an abnormality determination that is a determination as to whether or not the occurrence of at least one of a state and a third abnormal state in which fuel injection from the injector is not normally performed with respect to the injection command equipped with a,
The abnormality determination means performs the abnormality determination based on at least one of the following differences (a) to (c) including at least the pulse number difference (c), and the pulse (c) In the abnormality determination based on the number difference, when the pulse number difference is not 0, it is determined that the third abnormality state is present.
(A) A timing difference that is a difference between an injection start timing indicated by the injection command or the drive signal and an energization start timing indicated by the energization detection signal.
(B) A drive time difference which is a difference between an injection time from the start to the end indicated by the injection command or the drive signal and an energization time from the start to the end indicated by the energization detection signal.
(C) Each time the logic level of the drive signal changes to an active level indicating a period during which fuel injection is performed, the time during which the drive signal is at the active level is defined as one pulse in the drive signal, and the logic level of the energization detection signal is Each time the current level changes to an active level indicating a period during which the injector is energized, the active level is generated as a single pulse in the energization detection signal, and is generated during a predetermined determination period. Pulse number difference, which is the difference between the number of injection commands or the number of pulses of the drive signal and the number of pulses of the energization detection signal The fuel injection control device according to claim 4 ,
The abnormality determination means performs the abnormality determination based on the timing difference, and determines that the first abnormality state is present when the timing difference exceeds a preset timing difference threshold. A fuel injection control device. The fuel injection control device according to claim 4 or 5 ,
The abnormality determination unit performs the abnormality determination based on the driving time difference, and determines that the second abnormality state is present when the driving time difference does not fall within a preset time difference allowable range. A fuel injection control device. The fuel injection control device according to any one of claims 1 to 6 ,
A fuel injection control device comprising the drive device and being integrated with the drive device. The fuel injection control device according to any one of claims 1 to 6 ,
The drive device;
A fuel injection control system comprising: