JP2017145784A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device capable of detecting an acceleration side abnormal state and a deceleration side abnormal state even if any one of these abnormal states may occur.SOLUTION: An electronic control device 10 comprises a signal generating part for generating a TDC synchronous signal on the basis of a detection signal of a crank angle sensor, a task execution part for executing a synchronous task every time a rising edge of the TDC synchronous signal is generated, a measuring part for measuring an execution interval of the synchronous tasks every time they are executed, a threshold setting part, and a judgement part for judging the execution state of the synchronous tasks on the basis of the threshold. The threshold setting part sets a lower limit value for detecting an acceleration side abnormal state and an upper limit value for detecting a deceleration side abnormal state in response to the measured execution interval for every execution interval measurement to become a low value as the execution interval is shorter. The judgement part compares a subsequent execution interval of timing where the threshold is set with the threshold and judges that the execution state of the synchronous task is abnormal when the subsequent execution interval is less than the lower limit value or larger than the upper limit value.SELECTED DRAWING: Figure 3

Description

  The disclosure in this specification relates to an electronic control device capable of detecting an abnormality in an execution state of a synchronous task executed in synchronization with rotation of a crankshaft.

  Patent Document 1 discloses a signal generation unit that generates a crank synchronization signal, a task execution unit that executes a synchronization task based on the crank synchronization signal, a measurement unit that measures an execution interval of the synchronization task, and a threshold value according to the engine speed. An electronic control device including a threshold setting unit to be set and a determination unit that determines that the execution state of the synchronous task is abnormal when the execution interval exceeds the threshold is disclosed.

  In this electronic control device, the signal generation unit obtains a detection signal that rises every time the crankshaft of the engine rotates 10 ° CA from the crank angle sensor. Based on the acquired detection signal, a crank synchronization signal is generated that rises every time the crankshaft rotates 30 ° CA. The engine speed corresponds to the execution interval, which is the time required for the crankshaft to rotate 30 ° CA, and the threshold setting unit sets the threshold based on the engine speed.

JP 2001-323836 A

  As an abnormality in the execution state of the synchronous task, an abnormality on the acceleration side and an abnormality on the deceleration side can occur. As the acceleration-side abnormality, an abnormality in which the synchronous task is executed so that the execution interval is rapidly shortened can be considered. As the deceleration-side abnormality, an abnormality in which the synchronization task is executed so that the execution interval becomes abruptly long, an abnormality in which the synchronization task does not occur, an abnormality in which the synchronization task does not end, and the like are considered.

  In the conventional electronic control device, one threshold is set for a predetermined engine speed (execution interval), and when the execution interval exceeds the threshold, it is determined that the execution state of the synchronous task is abnormal. Therefore, the acceleration side abnormality cannot be detected.

  The present disclosure has been made in view of such problems, and an object thereof is to provide an electronic control device that can detect any of an acceleration-side abnormality and a deceleration-side abnormality.

  The present disclosure employs the following technical means to achieve the above object. In addition, the code | symbol in parenthesis shows the corresponding relationship with the specific means as described in embodiment mentioned later as one aspect | mode, Comprising: The technical scope is not limited.

One of the present disclosure acquires a detection signal of a crank angle sensor that detects a rotation angle of a crankshaft of an internal combustion engine, and generates a synchronization signal that rises every time the crankshaft rotates by a predetermined angle based on the detection signal Part (120),
A task execution unit (121) that executes a synchronization task each time an edge in a specific direction occurs in the synchronization signal;
A measurement unit (122) that measures the execution interval of the synchronization task for each execution of the synchronization task;
For each execution interval measurement, a lower limit value that is a threshold value for detecting an abnormality on the acceleration side and an upper limit value that is a threshold value for detecting an abnormality on the deceleration side are executed according to the measured execution interval. A threshold value setting unit (123) that sets a smaller value as the interval is shorter;
The set threshold value is compared with the next execution interval at the timing when the threshold value is set, and if the next execution interval is less than the lower limit value or larger than the upper limit value, the execution status of the synchronous task is abnormal. A determination unit (124) that determines that there is,
Is provided.

  According to this, for each measurement of the execution interval, the threshold setting unit sets the lower limit value for detecting the acceleration-side abnormality and the upper limit value for detecting the deceleration-side abnormality according to the measured execution interval. Set each. Then, the determination unit compares the set lower limit value and upper limit value with the execution interval measured at the next timing, and determines the presence or absence of abnormality from the comparison result. Therefore, it can be detected whether an abnormality on the acceleration side or an abnormality on the deceleration side occurs as an abnormality in the execution state of the synchronous task.

  In another one of the present disclosure, the signal generation unit generates a top dead center synchronization signal synchronized with the top dead center of the internal combustion engine as a synchronization signal.

  For example, in the case of a 4-cylinder internal combustion engine, a top dead center synchronization signal is generated every 180 ° CA. Accordingly, it is possible to suppress the occurrence of a deceleration-side abnormality, which takes time to determine the abnormality, and the execution of the synchronization task is lost (vacant). “CA” is a crank angle (crank angle).

It is a figure which shows schematic structure of the electronic controller which concerns on 1st Embodiment. It is a flowchart which shows the synchronous task process which a microcomputer performs. It is a timing chart for explaining detection of acceleration side abnormality. It is a flowchart which shows the abnormality detection process which a microcomputer performs. It is a figure which shows the correspondence of an engine speed and a threshold value. It is a timing chart for demonstrating the detection of the deceleration side abnormality. It is a flowchart which shows the abnormality detection process which a microcomputer performs in the electronic control apparatus which concerns on 2nd Embodiment.

  A plurality of embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding parts are given the same reference numerals.

(First embodiment)
First, a schematic configuration of the electronic control device according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 1, an electronic control device 10 according to the present embodiment is configured as an engine ECU (Electronic Control Unit) that controls an engine (internal combustion engine) mounted on a vehicle. The electronic control device 10 includes a microcomputer 12, an input circuit 14, an output circuit 16, a power circuit 18 and the like.

  The microcomputer 12 is a microcomputer configured with a CPU, a ROM, a RAM, a register, an I / O port, and the like. In the microcomputer 12, the CPU performs signal processing according to a control program stored in advance in the ROM, various data acquired from the outside, and the like while using a temporary storage function of the RAM or the register. Also, the signal obtained by this signal processing is output. In this way, the microcomputer 12 executes various functions. For example, the microcomputer 12 calculates a target torque to be output by the engine. Further, in order to generate the target torque required by the engine, a throttle valve (not shown) is controlled to an appropriate opening degree, and the fuel injection amount and ignition timing of the engine are controlled.

  The input circuit 14 causes the microcomputer 12 to input detection signals detected by various sensors such as a crank angle sensor attached to the engine. The input circuit 14 includes, for example, a waveform shaping circuit 140 that shapes the detection signal of the crank angle sensor to generate a crank synchronization signal.

  In this embodiment, the timing rotor attached to the crankshaft has 34 teeth with two missing teeth, and 34 pulses are generated when the crankshaft rotates once. For this reason, the detection signal of the crank angle sensor rises every time the crankshaft rotates by 10 ° CA. The waveform shaping circuit 140 generates a crank synchronization signal that rises every time the crankshaft rotates a predetermined angle from the detection signal of the crank angle sensor, and outputs the crank synchronization signal to the microcomputer 12. The crank synchronization signal has a pulse period longer than the pulse period of the detection signal of the crank angle sensor and shorter than the pulse period of the TDC synchronization signal described later. In the present embodiment, a crank synchronization signal that rises every 30 ° CA is generated.

  The output circuit 16 outputs a drive signal to various actuators such as a fuel injection valve and an igniter in accordance with a control signal output from the microcomputer 12.

  The power supply circuit 18 converts the battery voltage VB supplied from the vehicle battery into a predetermined voltage, and supplies the voltage to elements constituting the electronic control device 10 such as the microcomputer 12. The power supply circuit 18 steps down the battery voltage VB to 5 V, for example, and supplies it to the microcomputer 12.

  Next, the microcomputer 12 will be described.

  As illustrated in FIG. 1, the microcomputer 12 includes a signal generation unit 120, a task execution unit 121, a measurement unit 122, a threshold setting unit 123, and a determination unit 124.

  The signal generation unit 120 generates a TDC synchronization signal. The TDC synchronization signal is a signal that rises in synchronization with the top dead center of each cylinder of the engine. The signal generator 120 generates a TDC synchronization signal based on the crank synchronization signal while using the missing tooth position as a reference. The crank synchronization signal is generated based on the detection signal of the crank angle sensor as described above. Therefore, the TDC synchronization signal is a synchronization signal that rises every time the crankshaft rotates by a predetermined angle based on the detection signal of the crank angle sensor. In this embodiment, the engine has four cylinders, and the TDC synchronization signal rises every 180 ° CA. That is, every time the crank synchronization signal produces 6 pulses, the TDC synchronization signal produces 1 pulse.

  The task execution unit 121 executes a synchronization task when an edge in a specific direction occurs in the TDC synchronization signal. In this embodiment, the synchronization task is executed every time a rising edge occurs in the TDC synchronization signal. The task execution unit 121 executes processing related to engine control such as calculation of the engine speed Ne and cylinder discrimination as a synchronization task.

  The measurement unit 122 measures the execution interval of the synchronization task every time the synchronization task is executed. The execution interval is the time required for the crankshaft to rotate 30 ° CA. In the present embodiment, the measurement unit 122 has a counter that is reset when the synchronization task ends, and the counter takes a time from the end of the synchronization task to the end of the next synchronization task, That is, the execution interval is measured.

  For each measurement of the execution interval, the threshold setting unit 123 sets a threshold for detecting an abnormality in the execution state of the synchronous task according to the measured execution interval. The threshold value setting unit 123 sets a lower limit value for detecting an acceleration-side abnormality and an upper limit value for detecting a deceleration-side abnormality so that the threshold value becomes smaller as the execution interval is shorter. Since the execution interval is the time required for the crankshaft to rotate 30 ° CA as described above, a threshold value may be set according to the engine speed. Also in this case, the threshold value is set according to the execution interval.

  The acceleration-side abnormality is an abnormality in which the synchronous task is executed so that the execution interval is rapidly shortened due to, for example, a program runaway. An acceleration-side abnormality is an abnormality in which a synchronous task is executed on the high-speed side of the engine, that is, on the acceleration side of the vehicle with respect to a normal state. The deceleration-side abnormality is, for example, an abnormality in which a synchronous task is executed so that an execution interval becomes abruptly long due to a program runaway, an abnormality in which a synchronization task does not occur, and an abnormality in which a synchronization task does not end. The deceleration side abnormality is an abnormality that occurs on the low rotation side of the engine, that is, on the deceleration side of the vehicle with respect to a normal state.

  The determination unit 124 compares the threshold set by the threshold setting unit 123 with the next execution interval at the timing when the threshold is set. Then, the determination unit 214 determines that the execution state of the synchronous task is abnormal when the next execution interval is less than the lower limit value or larger than the upper limit value. On the other hand, when the next execution interval is within the range between the lower limit value and the upper limit value, it is determined that the execution state of the synchronous task is normal.

  Next, a synchronization task process and an abnormality detection process executed by the microcomputer 15 will be described with reference to FIGS.

  First, synchronous task processing will be described. The microcomputer 12 executes the process shown in FIG. 2 every time a rising edge occurs in the TDC synchronization signal. First, the microcomputer 12 executes an interrupt handler process (step S10). A synchronous task is activated by the interrupt handler process. Thereby, the microcomputer 12 performs a synchronous task process (step S12). When the synchronous task is activated, the interrupt handler process ends. In step S12, the predetermined process related to engine control is executed as described above. The processes in steps S10 and S12 are executed by the task execution unit 121.

  When the synchronization task ends, the microcomputer 12 resets the value of the counter Ctask for measuring the execution interval of the synchronization task to 0 (step S14). Then, a series of processing ends. The microcomputer 12 stores in the RAM in the microcomputer 12 at least one of the engine speed Ne obtained by the synchronous task processing and the value of the counter Ctask immediately before reset, that is, the execution interval.

  As shown in FIG. 3, in the synchronous task process, every time a rising edge occurs in the TDC synchronization signal, the interrupt handler process is executed, and consequently the synchronous task process is executed. When the synchronous task process ends, the counter Ctask is reset.

  Next, the abnormality detection process will be described. The microcomputer 12 executes the process shown in FIG. 4 at regular time intervals (for example, 1 ms). The microcomputer 12 gives priority to the interruption of the abnormality detection process over the synchronous task process described above. First, the microcomputer 12 determines whether or not a rising edge of the TDC synchronization signal has occurred within a preset predetermined time (step S20). In other words, it is determined whether or not a state where no rising edge occurs continues for a predetermined time or more. As the predetermined time, for example, a time during which the engine can be considered to be stopped is set.

If it is determined in step S20 that there is a rising edge, the microcomputer 12 sets a threshold to be compared with the execution interval T _n according to the previous execution interval T _n-1 stored in the memory (step S22). Specifically, the threshold setting unit 123, in response to the execution interval T _n-1 stored in the memory, to set the lower limit Tmin and the upper limit Tmax, which is compared to the execution interval T _n of the next timing. As described above, the threshold value may be set by the engine speed Ne corresponding to the execution interval T _n−1 . In this embodiment, a threshold value is set according to the engine speed Ne.

The threshold value setting unit 123 sets smaller values as the lower limit value Tmin and the upper limit value Tmax as the engine speed Ne is higher, that is, as the execution interval _Tn-1 is shorter. In the present embodiment, as shown in FIG. 5, a map indicating the correspondence relationship between the lower limit value Tmin and the upper limit value Tmax and the engine speed Ne is stored in the ROM in the microcomputer 12. The threshold setting unit 123 reads the lower limit value Tmin and the upper limit value Tmax at the engine speed Ne from the map, and sets the lower limit value Tmin and the upper limit value Tmax. However, the lower limit value Tmin and the upper limit value Tmax may be set according to the engine speed Ne by a predetermined function, not limited to the map.

  In the example shown in FIG. 5, when the engine speed Ne is 1000 rpm, values corresponding to the upper limit value 18 ms and the lower limit value 7 ms are set, and when the engine speed Ne is 2500 rpm, the upper limit value 11 ms and the lower limit value 4 ms are set. The corresponding value is set. Further, when the engine speed Ne is 5000 rpm, values corresponding to the upper limit value 7 ms and the lower limit value 2 ms are set. Since the counter Ctask is counted up by one by the process of step S28 described later, for example, the value corresponding to 18 ms is a value obtained by dividing 18 ms by the execution period (1 ms) of the abnormality detection process, that is, 18.

When the threshold value is set, the determination unit 124 of the microcomputer 12 then determines that the current execution interval T _n , that is, the current Ctask value is less than the lower limit value Tmin set according to the previous execution interval T _n−1 , or It is determined whether or not the upper limit value Tmax is exceeded (step S24). Then, when the execution interval Tn is less than the lower limit value Tmin, or when it is determined that the execution interval Tn is greater than the upper limit value Tmax, the microcomputer 12 determines that an abnormality has occurred in the execution state of the synchronization task, and executes the process at the time of the abnormality determination (Step S26). In step S26, for example, a process of setting an abnormality detection flag indicating that an abnormality has occurred in the execution of the synchronization task (setting 1) is performed. The abnormality detection flag is referred to in other processing (not shown) and used as a trigger for some fail-safe treatment (for example, reset of the microcomputer 12 or the like).

  After completion of the abnormality determination process, the microcomputer 12 increments the counter Ctask by 1 (step S28). Then, a series of processing ends. If it is determined in step S24 that the execution interval Tn is within the range between the lower limit value Tmin and the upper limit value Tmax, the process of step S28 is executed without executing the process of step S26. Then, a series of processing ends.

  If it is determined in step S20 that the rising edge of the TDC synchronization signal does not occur within the predetermined time, the microcomputer 12 resets the value of the counter Ctask to 0 (step S30) and ends the series of processes.

  Next, effects of the electronic control device 10 according to the present embodiment will be described.

In this embodiment, the signal generation unit 120 of the microcomputer 12 generates a TDC synchronization signal that rises every 180 ° CA based on the detection signal of the crank angle sensor, and the task execution unit 121 has a rising edge in the TDC synchronization signal. Run synchronization tasks as they occur. Moreover, the measurement part 122 of the microcomputer 12 measures the execution interval of a synchronous task for every execution of a synchronous task, and the threshold value setting part 123 respond | corresponds to the measured execution interval _Tn-1 for every measurement of an execution interval. A lower limit value Tmin for detecting an acceleration-side abnormality and an upper limit value Tmax for detecting a deceleration-side abnormality are set.

Then, the determination unit 124 of the microcomputer 12 compares the current execution interval T _n with the lower limit value Tmin and the upper limit value Tmax set according to the previous execution interval T _n−1 , and the execution interval T _n is the lower limit. If it is less than the value Tmin or greater than the upper limit value Tmax, it is determined that an abnormality has occurred in the execution state of the synchronous task.

Therefore, it can be detected whether an abnormality on the acceleration side or an abnormality on the deceleration side occurs as an abnormality in the execution state of the synchronous task. In FIG. 3, due to the program runaway of the microcomputer 12, the execution timing of the synchronous task is advanced, and the counter Ctask is reset until the value of the counter Ctask reaches the lower limit value Tmin. In such a case, since the current execution interval T _n is less than the lower limit value Tmin set according to the previous execution interval T _n−1 , an abnormality (acceleration-side abnormality) occurred in the execution state of the synchronous task. Can be detected. The acceleration-side abnormality may occur not only as described above but also due to an advance in the execution timing of the interrupt handler process due to an abnormality in the program, or an earlier generation timing of the TDC synchronization signal than the main body.

In FIG. 6, the program runs away during execution of the synchronization task, and the synchronization task does not end. In such a case, since the current execution interval T _n becomes larger than the upper limit value Tmax set according to the previous execution interval T _n−1 , an abnormality (deceleration-side abnormality) occurs in the synchronous task execution state. Can be detected. In addition to the above, the deceleration-side abnormality is not only synchronized with the program, but the synchronization task execution timing itself is delayed, the interrupt handler processing execution timing is delayed, and the TDC synchronization signal has a rising edge. This can occur due to the absence of a task. In any case, when the value of the counter Ctask exceeds the upper limit value Tmax, it can be detected that an abnormality has occurred. 3 and 6, the lower limit value Tmin and the upper limit value Tmax are indicated by a two-dot chain line.

In particular, in the present embodiment, the lower limit value Tmin and the upper limit value Tmax are set according to the previous execution interval T _n-1 (engine speed Ne). Therefore, even if the engine speed changes from low to high and a deceleration-side abnormality occurs at that timing, the abnormality detection delay can be suppressed.

  Further, in the present embodiment, the signal generation unit 120 of the microcomputer 12 generates a TDC synchronization signal that rises every 180 ° CA in synchronization with the top dead center, as a synchronization signal synchronized with the rotation of the crankshaft. Therefore, it is possible to prevent the execution of the synchronous task from being lost due to the occurrence of deceleration-side abnormality and the time required for abnormality determination.

  Further, in this embodiment, when it is determined that the rising edge of the TDC synchronization signal does not occur within a predetermined time, the determination as to whether the execution state of the synchronization task is normal is not executed. Therefore, when the engine is stopped (including when the engine is stalled), or when the TDC synchronization signal is not input to the microcomputer 12 due to a hardware failure such as signal wiring, it is erroneously assumed that the execution state of the synchronization task is abnormal. Can also be prevented.

(Second Embodiment)
This embodiment can refer to the preceding embodiment. For this reason, the description about the part which is common in the electronic control apparatus 10 shown to previous embodiment is abbreviate | omitted.

  FIG. 7 shows an abnormality detection process executed by the microcomputer 12 in the electronic control apparatus 10 according to the present embodiment. As shown in FIG. 7, the microcomputer 12 determines whether or not the engine is in a complete explosion state in place of the processing in step S20 described above (step S21). For example, the microcomputer 12 determines that the engine is in a complete explosion state when the engine rotational speed Ne is equal to or higher than a predetermined rotational speed (for example, 300 rpm). It is determined that

  When it is determined that the engine is in a complete explosion state, the above-described processing from step S22 is executed. That is, it is determined whether or not the execution state of the synchronization task is normal. On the other hand, if it is determined in step S21 that the engine is in the starting state before the complete explosion, step S30 described above is executed.

  As described above, in the start state before the complete explosion of the engine, it is not determined whether or not the execution state of the synchronous task is normal. Since it is determined whether or not the execution state of the synchronous task is normal only in a complete explosion state in which the engine speed Ne is stable, the accuracy of abnormality determination can be improved.

  Note that it is also possible to determine whether or not the engine is in a complete explosion state by the process of step S20 shown in the first embodiment.

  The disclosure of this specification is not limited to the illustrated embodiments. The disclosure encompasses the illustrated embodiments and variations by those skilled in the art based thereon. For example, the disclosure is not limited to the combination of elements shown in the embodiments. The disclosure can be implemented in various combinations. The technical scope disclosed is not limited to the description of the embodiments. The several technical scopes disclosed are indicated by the description of the claims, and should be understood to include all modifications within the meaning and scope equivalent to the description of the claims. .

  The microcomputer 12 has the signal generation part 120, and this signal generation part 120 showed the example which produces | generates a TDC synchronizing signal as a synchronizing signal. However, the crank synchronization signal may be a synchronization signal. In this case, the microcomputer 12 does not have the signal generation unit 120, and the input circuit 14 corresponds to the signal generation unit.

10 ... Electronic control unit,
12 ... Microcomputer,
120... Signal generator,
121 ... task execution unit,
122 ... measuring unit,
123 ... Threshold setting unit,
124 ... determination unit
14 ... Input circuit,
140 ... waveform shaping circuit,
16 ... output circuit,
18 ... Power supply circuit

Claims (5)

A signal generation unit (120) that acquires a detection signal of a crank angle sensor that detects a rotation angle of a crankshaft of an internal combustion engine and generates a synchronization signal that rises every time the crankshaft rotates by a predetermined angle based on the detection signal. When,
A task execution unit (121) that executes a synchronization task each time an edge in a specific direction occurs in the synchronization signal;
A measurement unit (122) that measures an execution interval of the synchronization task for each execution of the synchronization task;
For each measurement of the execution interval, a lower limit value that is a threshold value for detecting an abnormality on the acceleration side and an upper limit value that is a threshold value for detecting an abnormality on the deceleration side are determined according to the measured execution interval. , A threshold value setting unit (123) that sets a smaller value as the execution interval is shorter;
The set threshold value is compared with the next execution interval of the timing at which the threshold value is set, and the next task is less than the lower limit value or larger than the upper limit value, the synchronization task A determination unit (124) that determines that the execution state of is abnormal;
An electronic control device comprising:   The electronic control device according to claim 1, wherein the signal generation unit generates a top dead center synchronization signal synchronized with a top dead center of the internal combustion engine as the synchronization signal.   The electronic control device according to claim 1, wherein the signal generation unit generates a crank synchronization signal as the synchronization signal.   The determination unit does not determine whether or not the execution state of the synchronous task is normal in the start state before the complete explosion of the internal combustion engine, and the execution state of the synchronous task in the complete explosion state of the internal combustion engine The electronic control device according to claim 1, wherein the determination is performed.   The threshold value setting unit has a map showing a correspondence relationship between the lower limit value and the upper limit value and the execution interval, and sets the lower limit value and the upper limit value using the map. The electronic control apparatus of any one of Claims.

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