JP2010059857A - Electronic control unit of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic control unit for an internal combustion engine, determining accurately that the computing process is in an overloaded condition. <P>SOLUTION: A CPU 41 to execute the computing process in an ECU 40 executes tasks in the sequence according to their priorities, i.e. a rotation-synchronized task requested to be executed synchronously with rotation of the crank shaft 17 of the internal combustion engine 10, a time-synchronized task having a lower priority than the rotation-synchronized task and requested to be executed at prescribed intervals, and an idle task to be executed on the condition that the two above-described tasks are both out of execution. The ECU 40 measures the time of idle task execution and the time of rotation-synchronized task execution and determines that the computing process by the CPU 41 is in the overloaded condition when the time of idle task execution is equal to or shorter than the time of rotation-synchronized task execution. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic control device for controlling an internal combustion engine.

  An electronic control device for an internal combustion engine performs engine control including a plurality of processes by sequentially executing various processes necessary for controlling the engine based on predetermined execution priorities. Specifically, these various types of processing are requested to be executed in order of high priority, rotation synchronous processing that is required to be executed in synchronization with the rotation of the crankshaft of the internal combustion engine, and every predetermined time (for example, 10 ms). Time synchronization processing and idle task processing executed on condition that both the rotation synchronization processing and the time synchronization processing are not executed. When execution of a process with a high priority is requested during execution of a process with a low priority, the process with a high priority is interrupted after the process being executed is temporarily stopped.

  Here, as the rotational speed of the internal combustion engine increases, the number of executions of the rotation synchronization processing increases, and therefore the load on the CPU (central processing unit) that executes arithmetic processing in the electronic control device increases. When the load of the arithmetic processing increases with the increase of the rotation speed and reaches an overload state, there is a problem that the completion of the processing having the lower execution priority than the rotation synchronization processing is delayed or not executed, There is a risk that engine control cannot be continued. Incidentally, the occurrence of such inconvenience can be suppressed by adopting a CPU having a high processing capacity so as to give a large margin to the computing capacity. However, when such a CPU with high processing capability is adopted, the cost increases.

Therefore, conventionally, when it is determined that the arithmetic processing in the CPU is in an overload state, the engine control is performed without resetting the CPU by stopping the execution of the low priority processing and reducing the arithmetic load. Has been proposed (Patent Document 1).
JP 2002-366374 A

  By the way, in the electronic control device described in Patent Document 1, the CPU performs an overload state by comparing the load index value indicating the load state of the CPU with a predetermined threshold value (fixed value). It is determined whether or not. When setting such a threshold value, if a limit value of the processing capacity of the CPU is set, there is a possibility that the arithmetic processing in the CPU will fail when the load index value reaches the threshold value. Therefore, when setting the threshold value, it is necessary to set a value with a certain margin for the limit value of the processing capability. However, if such a margin is provided, it is determined that the CPU is still overloaded even though there is still a margin in the calculation processing by the CPU. I can't.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an electronic control device for an internal combustion engine that can accurately determine that the arithmetic processing is in an overload state.

In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 is a rotation synchronization process that is requested to be executed in synchronization with the rotation of the crankshaft of the internal combustion engine, and a process having a lower priority than the rotation synchronization process, and is executed at regular intervals. An electronic device comprising: a required time synchronization process; and an idle task process that is executed on condition that both the rotation synchronization process and the time synchronization process are not executed, based on their execution priorities. The control device measures the execution time of the idle task process and the execution time of the rotation synchronization process, and when the execution time of the idle task process is less than or equal to the execution time of the rotation synchronization process, The gist is to include an overload determination means for determining that the arithmetic processing is in an overload state.

  According to the above configuration, when the execution time of the idle task process and the execution time of the rotation synchronization process are actually measured, and the execution time of the idle task process is less than or equal to the execution time of the rotation synchronization process, the computing means is in an overload state It is determined that Here, the execution time of the idle task process tends to become shorter as the load of the operation process performed by the operation means becomes higher, so the load state of the operation process can be grasped based on the execution time of the idle task process. . Then, the actual execution time of the rotation synchronization process is set instead of a fixed value as a threshold for determining whether or not the calculation process is in an overload state. Since the actual execution time of the rotation synchronization process in which the number of executions increases as the rotational speed of the internal combustion engine increases in this way is set as the threshold value, an appropriate threshold value corresponding to the calculation situation at the time of determining the overload state Thus, it is possible to accurately determine that the arithmetic processing is overloaded in the electronic control unit.

  When measuring the execution time of the idle task process and the execution time of the rotation synchronization process, as described in claim 2, the execution time of the idle task process in the predetermined period and the rotation synchronization process in the predetermined period A mode in which the execution time is measured can be employed.

  Further, when measuring the execution time of the idle task process and the execution time of the rotation synchronization process, as described in claim 3, the execution time of the idle task process and the maximum execution time of the rotation synchronization process in a predetermined period It is also possible to adopt a mode in which measurement is performed. In this case, since the maximum execution time is compared with the execution time of the idle task process in the rotation synchronization process executed a plurality of times during engine operation, the calculation process is more overloaded. It can be determined with high accuracy.

  When setting the predetermined period, as described in claim 4, the overload determination unit may adopt a mode in which the predetermined period is set on the basis of the execution interval of the rotation synchronization processing.

  According to a fifth aspect of the present invention, in the electronic control device for an internal combustion engine according to any one of the first to fourth aspects, when the overload determination unit determines that the calculation unit is in an overload state. Further, the gist of the present invention is to execute a load reduction process for reducing the load on the calculation means.

  According to the above configuration, when the calculation means is determined to be in an overload state by the overload determination means, the load reduction process for reducing the load on the calculation means is executed. Continuation is suppressed, and it is possible to suppress the occurrence of inconveniences such as idle processing and time synchronization processing having lower priority than the rotation synchronization processing are not executed. Accordingly, the operation of the internal combustion engine can be appropriately continued.

  Specifically, the load reduction process may be a rotation speed reduction process for reducing the rotation speed of the internal combustion engine, as described in claim 6. In this case, the number of executions of the rotation synchronization process is reduced, so that the processing load is reduced.

  More specifically, as the rotational speed reduction process, an aspect in which the intake air amount of the internal combustion engine as described in claim 7 is reduced and corrected, and the ignition timing of the internal combustion engine as described in claim 8 is set. It is possible to adopt a mode in which the retardation is corrected, or a mode in which the required value for the output torque of the internal combustion engine is corrected so as to be reduced.

  Further, as the rotational speed reduction process, as described in claim 10, the speed change is performed so that a speed ratio which is a ratio of an input shaft rotational speed to an output shaft rotational speed of a transmission connected to the engine becomes small. It is possible to adopt a mode in which a shift request is made to the machine.

(First embodiment)
Hereinafter, a first embodiment of an electronic control device for an internal combustion engine according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of an internal combustion engine 10 controlled by an electronic control device for an internal combustion engine according to the present embodiment and its peripheral configuration.

  The internal combustion engine 10 has a plurality of cylinders 19. Pistons 16 are accommodated in the cylinders 19 so as to be able to reciprocate. The combustion chamber 12 is defined by the inner peripheral surface of the cylinders 19 and the top surface of the pistons 16. Is partitioned. The engine 10 is provided with a fuel injection valve 20 that injects fuel into the combustion chamber 12 and an ignition plug 18 that ignites an air-fuel mixture in the combustion chamber 12. The piston 16 is connected to a crankshaft 17 that is an output shaft of the internal combustion engine 10.

  An intake passage 11 for supplying intake air to the combustion chamber 12 includes a throttle valve 14 for adjusting the amount of intake air (intake air amount) flowing through the passage 11 and a throttle valve for adjusting the opening degree TA of the valve 14. An actuator 15 is provided. A throttle opening sensor 32 that outputs a signal corresponding to the opening TA of the valve 14 is attached to the throttle valve 14. An air flow meter 31 that outputs a signal corresponding to the intake air amount is attached to the intake passage 11 upstream of the throttle valve 14. The air supplied through the intake passage 11 and the fuel supplied from the fuel injection valve 20 are mixed in the combustion chamber 12 and ignited and burned by the ignition plug 18, and the exhaust gas after combustion enters the exhaust passage 13. Discharged. An oxygen concentration sensor 33 that outputs a signal corresponding to the oxygen concentration in the exhaust gas flowing through the exhaust passage 13 is attached to the exhaust passage 13.

  As the piston 16 reciprocates due to combustion of the air-fuel mixture in the combustion chamber 12, the crankshaft 17 rotates. The rotation of the crankshaft 17 is transmitted via an automatic transmission 60 to drive wheels (not shown) of a vehicle on which the engine 10 is mounted.

  The automatic transmission 60 is a known automatic transmission in which the ratio of the rotational speed Nin of the input shaft to the rotational speed Nout of the output shaft of the transmission 60, that is, the gear ratio (Nin / Nout) is automatically changed. It is. In this embodiment, a multi-stage transmission that can change the gear ratio stepwise is adopted as such an automatic transmission, but a continuously variable transmission that can adjust the gear ratio steplessly is also used. It can also be adopted.

  The internal combustion engine 10 is provided with various sensors in addition to the various sensors described above in order to grasp the operating state of the engine 10. Specifically, the crank angle sensor 34 for detecting the position of the crankshaft 17 that is rotated by the reciprocation of the piston 16 and the accelerator pedal depression amount for detecting the depression amount of the accelerator pedal (not shown) by the driver. A sensor 35 and the like are provided. Signals output by these sensors are input to the ECU 40 that controls the engine 10 in a comprehensive manner.

  The ECU 40 includes a central processing unit (CPU) 41 that executes arithmetic processing, a read-only memory (ROM) 42 that stores various control programs and data in advance, and a volatile property that temporarily stores arithmetic results of the CPU 41 and the like. A memory (RAM) 43 and a nonvolatile memory (EEPROM) 44 capable of rewriting stored data are provided. In addition, an A / D converter, an input / output interface, and the like (not shown) are also provided. This CPU 41 corresponds to a calculation means. The ECU 40 is electrically connected to a T-ECU 50 that generally controls the shift of the automatic transmission 60, and signals are input / output to / from the T-ECU 50.

  Like the ECU 40, the T-ECU 50 includes a central processing unit (CPU) (not shown) and the like, and determines a gear ratio based on the traveling state of the vehicle on which the automatic transmission 60 is mounted. Then, the automatic transmission 60 is controlled so that the determined gear ratio is obtained.

  The CPU 41 grasps the operating state of the internal combustion engine 10 based on signals from various sensors, and performs various processes necessary for control of the engine 10 based on predetermined execution priorities in accordance with the grasped operating state. By sequentially executing the engine control, a plurality of processes are performed. Various processing programs necessary for engine control are stored in the ROM 42. More specifically, a rotation synchronization task (corresponding to rotation synchronization processing) that is requested to be executed in synchronization with the rotation of the crankshaft 17 is requested in descending order of execution priority, and is executed at regular intervals (for example, 10 ms). Time synchronization tasks (corresponding to time synchronization processing) and idle tasks (corresponding to idle task processing) executed on condition that both the rotation synchronization task and the time synchronization task are not executed. When execution of a task with a high priority is requested during execution of a task with a low priority, the task being executed is temporarily stopped and then a task with a high priority is interrupted.

  Examples of the rotation synchronization task include ignition timing control for adjusting the ignition timing of the spark plug 18, control of the fuel injection timing and fuel injection amount in the fuel injection valve 20, and the like. The time synchronization processing includes, for example, throttle control for controlling the opening degree of the throttle valve 14 and air-fuel ratio control for converging the air-fuel ratio of the mixture in the combustion chamber 12 to the target air-fuel ratio based on the output value of the oxygen concentration sensor 33. Etc. Further, idle tasks are mainly classified into processes that are not directly related to the operation of the internal combustion engine. For example, a rewrite process (refresh process) of data such as various learning values stored in the EEPROM 44 is performed. Can be mentioned. Note that priorities are determined in a stepwise manner among a plurality of tasks that are classified as a rotation synchronization task and a time synchronization task, and the tasks are executed in order based on the determined priorities.

  By the way, as the rotational speed NE of the internal combustion engine 10 increases, the number of executions of the rotation synchronization task increases and the execution interval becomes shorter, so the load on the CPU 41 that executes the arithmetic processing increases. When the CPU 41 reaches an overload state due to such an increase in the rotational speed NE and the CPU 41 reaches an overload state, the completion of processing having a lower execution priority than the rotational synchronization task is delayed or not executed. May occur and engine control may not be continued.

  Therefore, the ECU 40 executes a “task execution time measurement process” for measuring the execution time Tr of the rotation synchronization task and the execution time Ti of the idle task in the predetermined period ΔT. Then, based on the measured execution times Tr and Ti, it is determined whether or not the CPU 41 is in an overload state by “load monitoring processing”, and when it is determined that the CPU 41 is in an overload state, the load of the arithmetic processing is reduced. I am doing so. The predetermined period ΔT is set as a predetermined period ΔT, which is a period based on the execution interval of the rotation synchronization task, that is, a period from the start of the rotation synchronization task to the start of the next rotation synchronization task.

  Hereinafter, with reference to FIG. 2, the execution modes of the rotation synchronization task, the time synchronization task, and the idle task executed by the CPU 41 will be described, and the embodiment of the “task execution time measurement process” will be described.

  FIG. 2A shows an example of an execution mode when the rotational speed NE of the crankshaft 17 is low, that is, when the rotational speed NE is low, and FIG. 2B shows when the rotational speed NE of the crankshaft 17 is high, that is, An example of an execution mode at the time of high rotation is shown. As shown in FIGS. 2A and 2B, the idle task execution time Ti within the predetermined period ΔT is higher in the state of FIG. 2B where the processing load on the CPU 41 becomes higher. It becomes shorter than the state of FIG.

  As described above, the rotation synchronization task, the time synchronization task, and the idle task have the highest priority of the rotation synchronization task. Therefore, when the rotation synchronization task is requested to execute, the rotation synchronization task is preferentially executed. The That is, as shown in FIG. 2A, when execution of the rotation synchronization task is requested at time t11, the rotation synchronization task is started from time t11 and ends at time t12. Similarly, when execution of the rotation synchronization task is requested at time t15, the rotation synchronization task is started from time t15 and ends at time t17. Here, in the “task execution time measurement process”, the period from the time t11 to the time t15 that is the execution interval of the rotation synchronization task is set as the predetermined period ΔT, and the rotation synchronization task execution time in the predetermined period ΔT. As Tr, the time from time t11 to time t12 is measured and stored in the RAM 43.

  When the execution of the time synchronization task is requested when the rotation synchronization task is not executed, the time synchronization task is started from the requested time. Further, when the execution of the time synchronization task is requested when the rotation synchronization task is already executed, the time synchronization task is started after the rotation synchronization task already executed is completed. On the other hand, when the execution of the rotation synchronization task is requested when the time synchronization task is already executed, the already executed time synchronization task is temporarily stopped and the rotation synchronization task is interrupted. After the rotation synchronization task ends, the stopped time synchronization task is resumed.

  That is, when execution of the time synchronization task is requested at time t13 when the rotation synchronization task is not executed, the time synchronization task is started from time t13 and ends at time t14. On the other hand, when the execution of the time synchronization task is requested at time t16 when the rotation synchronization task is already executed, the time synchronization task is started after waiting for time t17 when the rotation synchronization task already executed ends. The

  Further, the idle task is executed in a period from time t12 to time t13 in which neither the rotation synchronization task nor the time synchronization task is executed, and in a period from time t14 to time t15. Therefore, in the “task execution time measurement process”, the total time of the time from time t12 to time t13 and the time from time t14 to time t15 is measured as the idle task execution time Ti in the predetermined period ΔT. Is remembered.

  On the other hand, at the time of high rotation shown in FIG. 2B, when execution of the rotation synchronization task is requested at time t21, the rotation synchronization task is started from time t21 and ends at time t22. Similarly, when execution of the rotation synchronization task is requested at time t24, time t27, and time t29, the rotation synchronization task is preferentially started at the requested time. Here, for example, a period from time t21 to time t24, which is an execution interval of the rotation synchronization task, is a predetermined period ΔT1, a period from time 24 to time t27 is a predetermined period ΔT2, and a period from time t27 to time t29 is a predetermined period ΔT3. And Further, the rotation synchronization task execution time Tr in the predetermined period ΔT1 is rotated as the rotation synchronization task execution time Tr1, the rotation synchronization task execution time Tr in the predetermined period ΔT2 is rotated as the rotation synchronization task execution time Tr2, and the rotation synchronization task execution time Tr in the predetermined period ΔT3 is rotated. If the synchronous task execution time Tr3 is assumed, the respective rotation synchronization task execution times Tr1, Tr2, Tr3 in the predetermined periods ΔT1, ΔT2, ΔT3 are sequentially measured, and the latest measured rotation synchronization task execution time Tr is sequentially stored in the RAM 43. Updated.

  When the execution of the time synchronization task is requested at time t23, the requested time synchronization task is started from this time t23. However, if execution of the rotation synchronization task is requested at time t24 before the execution of the time synchronization task thus started is completed, the already executed time synchronization task is temporarily stopped and the rotation synchronization task is interrupted. The stopped time synchronization task is resumed from time t25 when the rotation synchronization task ends.

  Further, the idle task is executed in a period from time t22 to time t23 in which neither the rotation synchronization task nor the time synchronization task is executed, and in a period from time t26 to time t27. Here, in the “task execution time measurement process”, the idle task execution times Ti1 and Ti2 are sequentially measured in the predetermined periods ΔT1, ΔT2, and ΔT3) described above. That is, the time from time t22 to time t23 is measured as the idle task execution time Ti1 in the predetermined period ΔT1, and the time from time t26 to time t27 is measured as the idle task execution time Ti2 in the predetermined period ΔT2. Then, the latest measured idle task execution time Ti is sequentially updated in the RAM 43. Since the idle task is not executed in the predetermined period ΔT3, the idle task execution time Ti in the predetermined period ΔT3 is set to “0”.

  Next, with reference to FIG. 3, the execution procedure of the “load monitoring process” executed by the ECU 40 will be described. A series of processes shown in the flowchart of FIG. 3 is repeatedly executed at regular intervals. Note that the processing from step S100 to step S120 in the above-described “task execution time measurement processing” and “load monitoring processing” shown in FIG. 3 corresponds to the overload determination means in the present embodiment.

  In this series of processing, first, the rotation synchronization task execution time Tr and the idle task execution time Ti are read (step S100). Here, the rotation synchronization task execution time Tr and the idle task execution time Ti measured by the above-described “task execution time measurement process” and stored in the RAM 43 are read. For example, when this process is executed after the idle task execution time Ti1 shown in FIG. 2B is measured and before the idle task execution time Ti2 is measured, the rotation synchronization task execution time Tr1 And idle task execution time Ti1 are read.

  Since the idle task execution time Ti tends to become shorter as the calculation processing load increases in the CPU 41, the calculation processing load state can be grasped based on the idle task execution time Ti. In addition, although the time required for processing for one rotation synchronization task (for example, calculation of ignition timing for ignition timing control) can be predicted to some extent at the construction stage of the control program, actually, the internal combustion engine 10 or the same engine 10 may vary depending on the state of the vehicle on which the vehicle 10 is mounted.

  Therefore, in the next step, it is determined whether or not the read idle task execution time Ti is equal to or shorter than the rotation synchronization task execution time Tr described above (step S110). That is, the actually measured rotation synchronous task execution time Tr is set as a threshold value corresponding to the calculation status at the time of this determination, and compared with the idle task execution time Ti.

  If it is determined through this determination process that the idle task execution time Ti is longer than the rotation synchronization task execution time Tr (Ti> Tr) (step S110: NO), it is determined that the CPU 41 is not overloaded. This process is terminated.

  For example, when the idle task execution time Ti and the rotation synchronization task execution time Tr shown in FIG. 2A are read and the relationship (Ti> Tr) is satisfied, the determination process shown in step S110 is executed. In this case, the relationship “Ti ≦ Tr” is not satisfied. Therefore, it is determined that the calculation state at the time of this determination is not an overload state, and that there is a margin in the calculation processing of the CPU 41.

  On the other hand, when it is determined that the idle task execution time Ti is equal to or less than the rotation synchronization task execution time (Ti ≦ Tr) (step S110: YES), it is determined that the calculation status at the current determination is an overload state. (Step S120). Here, it is determined that the CPU 41 is in an overload state because the number of executions of the rotation synchronization task increases as the rotation speed NE increases.

  For example, when the idle task execution time Ti1 and the rotation synchronization task execution time Tr1 shown in FIG. 2B are read and have a relationship of (Ti1 ≦ Tr1), the determination process shown in step S110 is executed. In this case, since the relationship of “Ti ≦ Tr” is satisfied, the calculation state at the time of determination is determined to be an overload state.

When it is determined that the CPU 41 is in an overload state, the throttle opening degree TA is subsequently corrected to decrease (step S130), and this process is terminated.
In step S130, the throttle opening degree TA (= TAt−ΔTA) is obtained by subtracting the correction amount ΔTA from the target throttle opening degree TAt calculated based on the depression amount of the accelerator pedal, the engine speed, or the like. Then, the throttle actuator 15 is driven. As the correction amount ΔTA, an amount capable of reducing the engine processing speed of the CPU 41 by decreasing the engine rotational speed NE is set in advance. The process in step S130 corresponds to a rotation speed reduction process that is executed as the load reduction process.

  When the throttle opening degree TA is corrected to be reduced by the process of step S130, the amount of intake air supplied to the combustion chamber 12 of the internal combustion engine 10 decreases, and the rotational speed NE of the engine 10 decreases. Thereby, the execution mode of various tasks at the time of high rotation shown in FIG. 2B comes closer to the execution mode at the time of low rotation as shown in FIG. 2A, and the load on the CPU 41 is reduced. The

According to 1st Embodiment described above, there can exist the following effects.
(1) When the idle task execution time Ti and the rotation synchronization task execution time Tr are actually measured and the idle task execution time Ti is equal to or less than the rotation synchronization task execution time Tr, it is determined that the CPU 41 is in an overload state. (Step S120). Here, the rotation synchronization task execution time Tr, which is the actual execution time of the rotation synchronization task, is measured as a threshold for determining whether or not the CPU 41 is in an overload state, and the measured value is not a fixed value. Set as threshold. Thus, the actual execution time Tr of the rotation synchronization task whose number of executions increases as the engine speed NE of the internal combustion engine 10 increases is set as the threshold value. For this reason, an appropriate threshold value corresponding to the calculation situation at the time of determination of the overload state is set, whereby the ECU 40 accurately determines that the calculation process is in an overload state, that is, the CPU 41 is in an overload state. Will be able to.

  (2) When it is determined that the CPU 41 is in an overload state (step S120), the throttle opening degree TA is corrected to decrease as a load reduction process for reducing the load on the CPU 41 (step S130). Therefore, it is suppressed that the overload state of the arithmetic processing is continued, and it is possible to suppress the occurrence of inconvenience that the idle task and the time synchronization task having lower priority than the rotation synchronization task are not executed. Therefore, the operation of the internal combustion engine 10 can be continued properly.

  (3) As a load reduction process for reducing the load on the CPU 41, a rotation speed reduction process for reducing the engine rotation speed NE of the internal combustion engine 10 is executed. More specifically, since the reduction correction of the throttle opening degree TA is executed (step S130), the number of executions of the rotation synchronization task within a predetermined time can be reduced, thereby reducing the calculation processing load of the CPU 41. Become so.

  (4) While determining the overload state of the CPU 41 with high accuracy and reducing the load when the overload state is determined, the operation of the internal combustion engine 10 can be appropriately continued. Therefore, it is possible to appropriately maintain the engine control without adopting a CPU having a high processing capacity to give a large margin to the calculation capacity, and thus it is possible to suppress an increase in the cost of the ECU 40.

(Second Embodiment)
Next, a second embodiment that embodies an electronic control device for an internal combustion engine according to the present invention will be described with reference to FIG. 1, FIG. 4, and FIG.

  This embodiment differs from the first embodiment in the following points. That is, in the first embodiment, the “rotation synchronization task execution time Tr in the predetermined period ΔT is sequentially measured by the“ task execution time measurement process ”, and the rotation synchronization task stored in the RAM 43 is sequentially updated. In the “load monitoring process”, it is determined whether or not the CPU 41 is in an overload state with the rotation synchronization task execution time Tr as a threshold value.

  On the other hand, in the “task execution time measurement process” of the present embodiment, the rotation synchronization task execution time Tr in the predetermined period ΔT is sequentially measured, and the measured rotation synchronization task execution time Trmax is the maximum execution time Trmax. It is stored in the RAM 43. Then, the “load monitoring process” determines whether or not the CPU 41 is in an overload state with the maximum execution time Trmax as a threshold. Note that detailed description of the same processing as in the first embodiment is omitted.

First, the details of the “task execution time measurement process” will be described with reference to FIG.
Similar to the first embodiment, when execution of the rotation synchronization task is requested at time t31, time t34, and time 37, the rotation synchronization task is preferentially started at the requested time. Here, as described above, the time required for processing for one rotation synchronization task may vary depending on the state of the internal combustion engine 10 or the vehicle on which the engine 10 is mounted. Therefore, in the “task execution measurement process” in the present embodiment, the maximum execution time Trmax of the rotation synchronization task execution time Tr is stored in the RAM 43. Specifically, when the measured rotation synchronization task execution time Tr is compared with the maximum execution time Trmax previously stored in the RAM 43, the measured rotation synchronization task execution time Tr exceeds the maximum execution time Trmax. Updates the measured rotation synchronization task execution time Tr as the maximum execution time Trmax.

  For example, if the rotation synchronization task execution time Tr1 measured in the predetermined period ΔT1 (time t31 to time t34) shown in FIG. 4 exceeds the previously stored maximum execution time Trmax, this rotation synchronization task execution time Tr1 Thus, the maximum execution time Trmax is updated. On the other hand, when the rotation synchronization task execution time Tr2 measured in the predetermined period ΔT2 (time t34 to time t37) is equal to or shorter than the previously stored maximum execution time Trmax (Tr1), the stored maximum The execution time Trmax is held as it is.

  On the other hand, for the idle task, in the “task execution time measurement process”, the idle task execution time Ti1 (time t32 to time t33) in the predetermined period ΔT1 and the idle task execution time Ti2 (time t36 to time t36) in the predetermined period ΔT2. Time t37) is sequentially measured, and the latest measured idle task execution time Ti is sequentially updated in the RAM 43.

  Next, with reference to FIG. 5, an execution procedure of the “load monitoring process” of the present embodiment executed by the ECU 40 will be described. The series of processing shown in the flowchart of FIG. 5 is repeatedly executed at regular intervals. Note that the above-described “task execution time measurement processing” and the processing from step S200 to step S220 in the “load monitoring processing” shown in FIG. 5 correspond to the overload determination means in the present embodiment.

  In this series of processing, first, the maximum execution time Trmax and the idle task execution time Ti are read (step S200). Here, the maximum execution time Trmax and the idle task execution time Ti stored in the RAM 43 are read by the “task execution time measurement process”.

Then, it is determined whether or not the idle task execution time Ti is equal to or shorter than the maximum execution time Trmax (step S210).
If it is determined through this determination process that the idle task execution time Ti is longer than the maximum execution time Trmax (Ti> Trmax) (step S210: NO), the calculation status at this determination is not an overload state. After the determination, this process is terminated.

  On the other hand, when it is determined that the idle task execution time Ti is equal to or shorter than the maximum execution time Trmax (Ti ≦ Trmax) (step S210: YES), it is determined that the calculation state at this determination is an overload state. (Step S220).

  For example, when the idle task execution time Ti1 and the maximum execution time Trmax shown in FIG. 4 are read and the relationship (Ti1 <Trmax) is satisfied, when the determination process shown in step S210 is executed, “ Since the relationship of “Ti1 ≦ Trmax (= Tr1)” is satisfied, the calculation state at the time of this determination is determined to be an overload state.

  If it is determined that the CPU 41 is in an overload state, the throttle opening degree TA is corrected to decrease (step S230), and this process is terminated. The process in step S230 is the same as the process in step S130.

  For example, in the case of FIG. 4 described above, there is a relationship such as the rotation synchronization task execution time Tr1 (= maximum execution time Trmax)> the idle task execution time Ti2> the rotation synchronization task execution time Tr2, and the first implementation described above. When the “load monitoring process” in the embodiment is executed and the idle task execution time Ti2 is compared with the rotation synchronization task execution time Tr2, the relation of (Ti2> Tr2) is established, and therefore the determination result indicating that the state is an overload state is I can't get it. However, according to the “load monitoring process” in the present embodiment, the maximum execution time Trmax of the rotation synchronization task execution time Tr is set as a threshold used for overload determination. Therefore, in step S210, the rotation synchronous task execution time Tr1 stored as the maximum execution time Trmax is compared with the idle task execution time Ti2, and an affirmative determination is made in step S210 (Trmax> idle task execution time Ti2). Thus, it can be determined with higher accuracy that the CPU 41 is in an overload state.

According to 2nd Embodiment demonstrated above, in addition to the effect shown to said (1)-(4), there can exist the following effects.
(5) The “task execution time measurement process” compares the maximum execution time Trmax with the idle task execution time Ti in the rotation synchronization task executed a plurality of times during engine operation, and the calculation process is overloaded. The state can be determined with higher accuracy.

(Third embodiment)
Next, a third embodiment that embodies an electronic control device for an internal combustion engine according to the present invention will be described with reference to FIG. 1, FIG. 6, and FIG.

  This embodiment differs from the first embodiment in the following points. That is, in the “task execution time measurement process” of the first embodiment, the period from the start of the rotation synchronization task to the start of the next rotation synchronization task, that is, 1 based on the execution interval of the rotation synchronization task. A period including the execution of the rotation synchronization task of the number of times was set as the predetermined period ΔT. On the other hand, in the “task execution time measurement process” of the present embodiment, a period including the execution of a predetermined number of rotation synchronization tasks is set as the predetermined period ΔT with reference to the execution interval of the rotation synchronization tasks. For example, when the specified number of times is 3, the first rotation synchronization task is started, the second and third rotation synchronization tasks are executed, and the next rotation synchronization task is started. The period until it is set is set as a predetermined period ΔT. Further, in the “load determination process” of the present embodiment, the rotation synchronization task integration execution time TrS, which is an integrated value of the rotation synchronization task execution time Tr during the predetermined period ΔT, and the integration of the idle task execution time Ti during the predetermined period ΔT. It is determined whether or not the CPU 41 is in an overload state by comparing the idle task integration execution time TiS, which is a value. Note that detailed description of the same processing as in the first embodiment is omitted.

  First, the details of the “task execution time measurement process” in the present embodiment will be described with reference to FIG. Here, an example will be described in which the prescribed number of rotation synchronization tasks in the predetermined period ΔT is three, but this prescribed number can be changed as appropriate.

  As in the first embodiment, when execution of the rotation synchronization task is requested at time t41, time t44, time t47, and time t49, the rotation synchronization task is preferentially started at the requested time. Here, in the “task execution time measurement process” of the present embodiment, since the specified number of times is set to 3, the period from time t41 to time t49 is set as the predetermined period ΔT. Then, as the rotation synchronization task integration execution time TrS in the predetermined period ΔT, a total time of execution times of the three rotation synchronization tasks executed in the predetermined period ΔT is measured and stored in the RAM 43. In the example shown in FIG. 6, the total of the time from time t41 to time t42, the time from time t44 to time t45, and the time from time t47 to time t48 is stored as the rotation synchronization task integration execution time TrS. The

  On the other hand, the idle task is executed in a period from time t42 to time t43 in which neither the rotation synchronization task nor the time synchronization task is executed, or in a period from time t46 to time t47. Therefore, in the “task execution time measurement process”, the total time of the time from time t42 to time t43 and the time from time t46 to time t47 is measured as the idle task integration execution time TiS in the predetermined period ΔT and stored in the RAM 43. Remembered.

  Next, with reference to FIG. 7, the execution procedure of the “load monitoring process” of the present embodiment executed by the ECU 40 will be described. The series of processing shown in the flowchart of FIG. 7 is repeatedly executed at regular intervals. Note that the processing from step S300 to step S320 in the above-described “task execution time measurement processing” and “load monitoring processing” shown in FIG. 7 corresponds to the overload determination means in the present embodiment.

  In this series of processing, first, rotation synchronous task integration execution time TrS and idle task integration execution time TiS are read (step S300). Here, the rotation synchronous task integration execution time TrS and the idle task integration execution time TiS measured by the “task execution time measurement process” and stored in the RAM 43 are read.

Then, it is determined whether or not the read idle task integration execution time TiS is equal to or less than the rotation synchronization task integration execution time TrS (step S310).
If it is determined through this determination processing that the idle task integration execution time TiS is longer than the rotation synchronization task integration execution time TrS (TiS> TrS) (step S310: NO), the calculation status at this determination is overload. It is determined that it is not in a state, and this process is terminated as it is.

  On the other hand, when it is determined that the idle task execution time Ti is equal to or less than the rotation synchronization task execution time (TiS ≦ TrS) (step S310: YES), it is determined that the calculation state at this determination is an overload state. (Step S320).

  For example, when the idle task integration execution time TiS and the rotation synchronization task integration execution time TrS shown in FIG. 6 are read and have a relationship of (TiS ≦ TrS), the determination process shown in step S310 is executed. In this case, since the relationship of “TiS ≦ TrS” is satisfied, the calculation state at the time of this determination is determined to be an overload state.

  If it is determined that the CPU 41 is in an overload state, the throttle opening degree TA is corrected to decrease (step S330), and the series of processes is terminated. The process in step S330 is the same as the process in step S130.

  As mentioned above, according to 3rd Embodiment demonstrated, there can exist an effect similar to the effect shown to said (1)-(4). In addition, since the predetermined period ΔT is set longer than in the first embodiment and the second embodiment, the execution period of the “load monitoring process” can be lengthened. It is also possible to reduce the calculation load of the CPU 41 accompanying the execution of “”.

(Fourth embodiment)
Next, with reference to FIG.1 and FIG.8, difference with the said 1st Embodiment is demonstrated about 4th Embodiment which actualized the electronic controller of the internal combustion engine concerning this invention.

  In the first embodiment, the throttle opening degree TA is decreased and corrected as the rotational speed reduction process executed as the load reduction process. However, in the present embodiment, the ignition timing of the internal combustion engine 10 is corrected to be retarded. In this way, the process of step S130 shown in FIG. 3 is changed to the process of step S430 shown in FIG.

  That is, in the “load monitoring process” in the present embodiment, if the CPU 41 is determined to be in an overload state in step S120 described in the first embodiment, the ignition timing T is corrected to be retarded (step S430). This process is terminated.

  In this step S430, the ignition timing of the spark plug 18 is retarded so that the ignition timing T is retarded by the correction amount ΔT from the ignition timing T set based on the engine operating state. This correction amount ΔT is set in advance to an amount that can reduce the engine rotational speed NE and reduce the processing load of the CPU 41. The engine rotational speed NE can also be reduced by such ignition timing retardation correction. Note that the process of step S430 corresponds to a rotation speed reduction process executed as a load reduction process in the present embodiment.

Also according to the fourth embodiment, it is possible to achieve the effects similar to the effects shown in the above (1) to (4).
(Fifth embodiment)
Hereinafter, with reference to FIG.1 and FIG.9, difference with the said 1st Embodiment is demonstrated about 5th Embodiment which actualized the electronic controller of the internal combustion engine concerning this invention.

  In the first embodiment, the throttle opening degree TA is corrected to decrease as the rotational speed reduction process executed as the load reduction process. However, in this embodiment, the accelerator pedal depression amount, the engine rotational speed NE, and the like are corrected. The required torque of the engine calculated based on the above is reduced and corrected. This embodiment is implemented by changing the process of step S130 shown in FIG. 3 to the process of step S530 shown in FIG.

  That is, in the “load monitoring process” in the present embodiment, if the CPU 41 is determined to be in an overload state in step S120 described in the first embodiment, the required torque TO is corrected to decrease (step S530), Processing is terminated.

  In step S530, a required torque TO (= TOt−ΔTO) obtained by reducing the target required torque TOt by the correction amount ΔTO is calculated, and the engine output is controlled so that the required torque TO is obtained. The target required torque TOt is calculated based on the accelerator pedal depression amount detected by the accelerator pedal depression amount sensor 35, the engine rotational speed NE detected by the crank angle sensor 34, and the like. The correction amount ΔTO is set in advance so that the engine rotational speed NE can be reduced to reduce the load of the arithmetic processing of the CPU 41.

  When the reduction correction of the required torque TO is performed, the opening degree of the throttle valve 14 is driven to drive the throttle actuator 15 so as to supply the intake air amount calculated according to the reduced correction required torque TO. Adjusted through. Thereby, the engine speed NE can be reduced. Note that the process of step S530 corresponds to a rotation speed reduction process executed as a load reduction process in the present embodiment.

Also according to the fifth embodiment, it is possible to achieve the effects similar to the effects shown in the above (1) to (4).
(Sixth embodiment)
Hereinafter, with reference to FIG. 1 and FIG. 10, the difference between the sixth embodiment that embodies the electronic control device for an internal combustion engine according to the present invention and the first embodiment will be described.

  In the first embodiment, the throttle opening degree TA is decreased and corrected as the rotational speed reduction process executed as the load reduction process. However, in this embodiment, the gear ratio of the automatic transmission 60 is reduced. In addition, the shift of the automatic transmission 60 is controlled. This embodiment is implemented by changing the process of step S130 shown in FIG. 3 to the process of step S630 shown in FIG.

  That is, if it is determined in step S120 that the CPU 41 is in an overload state, a gear change request is made so that the gear ratio becomes small (step S630), and this process ends.

  Specifically, the ECU 40 outputs a shift request to the T-ECU 50 so that the gear ratio of the automatic transmission 60 is reduced. The T-ECU 50 that has received this gear shift request issues a gear shift instruction to the automatic transmission 60 so that the gear ratio becomes small, and the automatic transmission 60 performs an upshift. For example, if the current gear position is the third gear, the gear is shifted up to the fourth gear. As a result, the rotational speed Nin of the input shaft relative to the rotational speed Nout of the output shaft of the automatic transmission 60 is reduced, and the rotational speed of the crankshaft 17, that is, the engine rotational speed NE can be reduced. Note that the process of step S630 corresponds to a rotational speed reduction process executed as a load reduction process in the present embodiment.

Also according to the sixth embodiment, it is possible to achieve the effects similar to the effects shown in the above (1) to (4).
(Other embodiments)
The electronic control device for an internal combustion engine according to the present invention is not limited to the configuration exemplified in each of the above-described embodiments, and may be implemented as, for example, the following forms obtained by appropriately modifying the embodiments. it can.

  In each of the first to third embodiments, the example in which the intake air amount is reduced by reducing the opening degree TA of the throttle valve 14 has been described. However, the intake air amount of the internal combustion engine 10 is corrected to decrease. Other examples may be adopted as long as they can be used. For example, the internal combustion engine 10 is provided with a variable valve mechanism that changes the valve characteristics of the intake valve involved in the adjustment of the intake air amount, and the intake air amount of the internal combustion engine 10 is corrected to decrease through control of the variable valve mechanism. Aspects may be adopted. Further, the intake air amount may be corrected to decrease by combining the control of the throttle opening degree TA and the control of the variable valve mechanism.

  In each of the first to third embodiments, the example in which the preset correction amount ΔTA is applied has been described. However, an aspect in which the correction amount ΔTA is variable according to the load state of the CPU 41 may be employed. . For example, the greater the difference between the idle task execution time Ti and the rotation synchronization task execution time Tr when the CPU 41 is determined to be in an overload state in the “load monitoring process”, that is, the higher the degree of overload, the more A mode in which the amount ΔTA is set to be large can be employed.

  In each of the fourth to sixth embodiments, the example in which the mode of the rotation speed reduction process executed in the “load determination process” of the first embodiment is changed is shown. However, the aspect of the rotational speed reduction process executed in the “load determination process” of the second or third embodiment is also the same as the aspect of the rotational speed reduction process shown in the fourth to sixth embodiments. You may make it change each.

  Furthermore, in each of the above embodiments, when the CPU 41 determines that it is in an overload state, any one of the throttle opening degree TA, the ignition timing T, the required torque TO, and the gear ratio change request is performed as the rotational speed reduction process. Although an example of execution is shown, these rotation speed reduction processes may be executed in combination as appropriate.

  In each of the above embodiments, an example in which the rotation speed reduction process is executed as the process for reducing the load on the CPU 41 has been described. However, when the CPU 41 is determined to be in an overload state, the load on the CPU 41 can be reduced. Other processes may be executed as long as they can be performed. For example, it is possible to adopt a mode in which the number of executions of a task with a low priority among the plurality of tasks classified as the rotation synchronization task is reduced.

  In the “task execution time measurement process” of the second embodiment, the rotation synchronization task execution time Tr in the predetermined period ΔT is sequentially measured, and the latest rotation synchronization task execution time Tr measured is stored in advance. The maximum execution time Trmax is updated by comparing the maximum execution time Trmax. However, the setting mode of the maximum execution time Trmax is not limited to this example. For example, the measured rotation synchronization task execution time Tr is stored until a predetermined number of measurements are completed, and the longest of the stored rotation synchronization task execution times Tr is set as the maximum execution time Trmax. It may be set and updated. In this case, a more appropriate maximum execution time Trmax corresponding to the calculation situation when determining the overload state of the CPU 41 can be set as the threshold value.

  In the “task execution time measurement process” of the third embodiment, the rotation synchronization task integration execution time TrS in a predetermined period ΔT is measured, and the measured rotation synchronization task integration execution time TrS is used for determination of overload. Although an example of setting as the threshold value has been shown, other values can be adopted as the threshold value for determining the overload state of the CPU 41. For example, the maximum execution time Trmax described in the second embodiment is measured, and the value obtained by multiplying the maximum execution time Trmax by the number of executions of the rotation synchronization task in a predetermined period ΔT is used as the threshold value. You can also For example, in the example shown in FIG. 6, a value obtained by multiplying the measured maximum execution time Trmax by “3” can be set as the threshold value.

  In addition, in each of the above-described embodiments, an example in which the predetermined period ΔT is set based on the execution interval of the rotation synchronization task is shown. However, the predetermined period ΔT is not necessarily based on the execution interval of the rotation synchronization task. I don't need it. That is, a predetermined period fixed in advance may be set. In short, by setting the execution time of the time synchronization task actually measured as a threshold value, the operational effect shown in the above (1) can be achieved.

  In addition, when comparing the execution time of the rotation synchronization task and the execution time of the idle task, the values are not directly compared as shown in each of the above embodiments, but the ratio of these execution times. Thus, the overload state of the CPU 41 may be determined.

  The internal combustion engine controlled by the ECU 40 in each of the above embodiments is not limited to the example of the internal combustion engine 10 described above, and may be changed as appropriate. For example, an internal combustion engine including a port injection type fuel injection valve that injects fuel into the intake passage 11 may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing an internal combustion engine controlled by an electronic control device and its peripheral configuration in a first embodiment that embodies an electronic control device for an internal combustion engine according to the present invention. FIG. 5 is a time chart showing execution modes of a rotation synchronization task, a time synchronization task, and an idle task according to the embodiment, where (a) shows a time chart at a low rotation time, and (b) shows a time chart at a high rotation time. The flowchart which shows the execution procedure about the "load monitoring process" concerning the embodiment. The time chart which shows the execution aspect of the rotation synchronous task, time synchronous task, and idle task concerning 2nd Embodiment. The flowchart which shows the execution procedure about the "load monitoring process" concerning the embodiment. The time chart which shows the execution aspect of the rotation synchronous task, time synchronous task, and idle task concerning 3rd Embodiment. The flowchart which shows the execution procedure about the "load monitoring process" concerning the embodiment. The flowchart which shows a part of the execution procedure about the "load monitoring process" concerning 4th Embodiment. The flowchart which shows a part of the execution procedure about the "load monitoring process" concerning 5th Embodiment. The flowchart which shows a part of execution procedure about "load monitoring processing" concerning a 6th embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Intake passage, 12 ... Combustion chamber, 13 ... Exhaust passage, 14 ... Throttle valve, 15 ... Actuator for throttle, 16 ... Piston, 17 ... Crankshaft, 18 ... Spark plug, 19 ... Cylinder, 20 DESCRIPTION OF SYMBOLS ... Fuel injection valve, 31 ... Air flow meter, 32 ... Throttle opening sensor, 33 ... Oxygen concentration sensor, 34 ... Crank angle sensor, 35 ... Accelerator pedal depression amount sensor, 40 ... Electronic control unit (ECU), 41 ... Central processing Device (CPU), 42 ... Read-only memory (ROM), 43 ... Volatile memory (RAM), 44 ... Non-volatile memory (EEPROM), 50 ... T-ECU, 60 ... Automatic transmission.

Claims (10)

A rotation synchronization process that is requested to be executed in synchronization with the rotation of the crankshaft of the internal combustion engine; a time synchronization process that is a process having a lower priority than the rotation synchronization process and is required to be executed at regular intervals; and An electronic control device comprising arithmetic means for executing idle task processing executed on the condition that both the rotation synchronization processing and the time synchronization processing are not executed, based on their execution priority,
The execution time of the idle task process and the execution time of the rotation synchronization process are measured, and when the execution time of the idle task process is equal to or less than the execution time of the rotation synchronization process, the calculation process by the calculation means is overloaded An electronic control device for an internal combustion engine, comprising overload determination means for determining that The electronic control device for an internal combustion engine according to claim 1,
The electronic control device for an internal combustion engine, wherein the overload determination unit measures an execution time of the idle task process in a predetermined period and an execution time of the rotation synchronization process in the predetermined period. The electronic control device for an internal combustion engine according to claim 1,
The electronic control device for an internal combustion engine, wherein the overload determination means measures an execution time of the idle task process and an execution time of the rotation synchronization process and a maximum execution time thereof in a predetermined period. The electronic control device for an internal combustion engine according to claim 2 or 3,
The electronic control device for an internal combustion engine, wherein the overload determination means sets the predetermined period on the basis of an execution interval of the rotation synchronization process. The electronic control device for an internal combustion engine according to any one of claims 1 to 4,
An electronic control apparatus for an internal combustion engine, wherein when the overload determination means determines that the calculation means is in an overload state, a load reduction process for reducing the load on the calculation means is executed. The electronic control device for an internal combustion engine according to claim 5,
The electronic control device for an internal combustion engine, wherein the load reduction process is a rotational speed reduction process for reducing the rotational speed of the internal combustion engine. The electronic control device for an internal combustion engine according to claim 6,
An electronic control device for an internal combustion engine, wherein the amount of intake air of the internal combustion engine is corrected to decrease as the rotation speed reduction process. The electronic control device for an internal combustion engine according to claim 6 or 7,
An electronic control device for an internal combustion engine, wherein, as the rotation speed reduction process, the ignition timing of the internal combustion engine is corrected to be retarded. The electronic control device for an internal combustion engine according to any one of claims 7 to 8,
An electronic control device for an internal combustion engine, wherein the required value for the output torque of the internal combustion engine is reduced and corrected as the rotational speed reduction process. The electronic control device for an internal combustion engine according to any one of claims 6 to 9,
A transmission is connected to the engine,
An electronic engine for an internal combustion engine, wherein the speed change process is performed such that a speed change request is made to the transmission so that a speed change ratio that is a ratio of an input shaft rotation speed to an output shaft rotation speed of the transmission is reduced. Control device.

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