JP7457212B2 - engine control device - Google Patents

Description

Cross-reference of related applications

This application is based on patent application No. 2022-27195 filed in Japan on February 24, 2022, and the contents of the original application are incorporated by reference in their entirety.

The present disclosure relates to an engine control device, and more particularly, an engine control device that uses a nonvolatile memory that has a data storage area, is capable of writing and erasing data, and has a write count storage area and stores the write count. Regarding.

A technique for using a nonvolatile memory in an engine control device and limiting the number of times of writing to the nonvolatile memory is disclosed in Patent Document 1.

Japanese Patent Application Publication No. 7-287604

The engine control device described in Patent Document 1 is able to avoid writing to a nonvolatile memory exceeding the limit number of times. However, since writing stops when the limit number of times is reached, the function of the corresponding control in the engine control device deteriorates.

The present disclosure aims to provide a countermeasure against writing to a non-volatile memory that exceeds the limit number of times while preventing functional deterioration of engine control.

One aspect of the present disclosure is a non-volatile memory that has a data storage area, allows data to be written and erased, and has a write count storage area to store the write count; This is an engine control device that includes a computer that performs writing and reading.

Then, the computer of the present disclosure determines a use upper limit value indicating the upper limit number of times per usage period of the engine control device from the maximum guaranteed number of writes guaranteed by the nonvolatile memory for the expected product life period of the engine control device. The computer also counts the number of actual writes to the nonvolatile memory and creates an actual write value indicating the actual number of writes per period of use of the engine control device. When the computer determines that the actual write value exceeds the upper limit of use by a predetermined value or more, the computer performs write restriction processing to reduce the number of writes to the nonvolatile memory.

The engine control device of the present disclosure can detect at an early stage the possibility of future writing to nonvolatile memory exceeding the limit number of times. By performing write restriction processing, it is possible to avoid functional deterioration (stopping memory writing) during the product life.

In other aspects of the present disclosure, when the computer determines that the actual write value is lower than the upper limit value by a predetermined value or more due to the write restriction process, the computer cancels the write restriction process. Since the write restriction process is an emergency measure, if the write frequency returns to normal, engine control will also return to normal.

In still another aspect of the present disclosure, the write restriction process is a process in which a threshold value for restricting writing is set in advance, and this threshold value is used to reduce the number of writes to the nonvolatile memory. In engine control, control may be performed even if write processing is restricted if the new value does not exceed a threshold value. When performing such control, the number of writes can be reduced by using a threshold value.

In still another aspect of the present disclosure, the computer creates an ideal write value with a write count less than the upper limit value. If it is determined that the actual write value exceeds the ideal write value, it is determined whether or not to give advance notice of writing restriction processing.

In still another aspect of the present disclosure, the computer performs control of a plurality of groups classified by engine control function, and the write restriction process is applied in descending order of the number of writes among the control groups of the plurality of groups. The write restriction process can be performed efficiently by performing the write restriction process in descending order of the number of writes.

In still another aspect of the present disclosure, the computer performs control of a plurality of groups classified by engine control function, and the write restriction process is performed in descending order of priority for performing engine control among the plurality of control groups. Applied. By performing engine control in descending order of priority for groups, it is possible to suppress functional deterioration due to write restriction processing.

In still another aspect of the present disclosure, the computer stores the number of writes to the nonvolatile memory after the previous write is completed, detects the number of writes to the nonvolatile memory after the current write ends, and the write restriction process includes: The number of writes to the nonvolatile memory is reduced based on the write limit, which is the difference between the number of writes after the previous write to the nonvolatile memory and after the current write.

Still another engine control device of the present disclosure further includes a display that shows the operating status of the computer to the user. Then, the computer outputs a warning flag to the display to indicate that the write restriction process is being performed. The occupant can understand from the warning flag that the write restriction process is in progress.

According to still another aspect of the present disclosure, when it is determined that the actual written value exceeds the ideal written value, a notice flag is output to the display to indicate that the actual written value exceeds the ideal written value. The occupant can understand from the notice flag that the condition exceeds the ideal written value.

Still another computer of the present disclosure determines whether the actual write value exceeds the guaranteed number of times ratio with respect to the maximum guaranteed number of writes, performs write restriction processing when the actual written value exceeds the guaranteed number of times ratio, and If the value does not exceed the guaranteed number of times ratio, a more relaxed process than the write restriction process is performed. Prior to performing write restriction processing, by performing a relaxation process that is more relaxed than write restriction processing, the effect of functional deterioration (memory writing stoppage) during the product life can be somewhat reduced, but the functionality of the engine control device can be maintained. be able to.

Still another computer of the present disclosure determines whether the actual usage time of the engine control device exceeds a guaranteed period ratio with respect to the assumed product life period, and performs write restriction processing when the actual usage time exceeds the guaranteed period ratio. If the actual usage time does not exceed the guaranteed period ratio, a more relaxed process than the write restriction process is performed. In this still other disclosure, prior to performing the write restriction process, a relaxation process that is more relaxed than the write restriction process is performed. As a result, although the effect of functional deterioration (stopping of memory writing) during the product life is somewhat reduced, the functionality of the engine control device can be maintained.

Yet another mitigation process of the present disclosure does not establish the write restriction process. In other words, the mitigation process is designed to perform normal write processing. Although the effect of functional degradation during the product life (stopping memory writing) is not obtained, the functionality of the engine control device can be maintained.

In still another relaxation process of the present disclosure, the write restriction process is not established until the write restriction process continues the number of times of relaxation. That is, in the relaxation process, if the write restriction process does not continue the number of relaxation times, normal write processing is performed. Although the effect of functional deterioration (stopping memory writing) during the product life cannot be fully obtained, the functionality of the engine control device can be maintained.

Still another write restriction process according to the present disclosure is a process in which a write threshold for restricting writing is set in advance, and the write threshold is used to reduce the number of writes to the nonvolatile memory. The relaxation process is a process of relaxing the reduction in the number of writes to the nonvolatile memory using a relaxation threshold that is more relaxed than the write threshold of the write restriction process. That is, the relaxation threshold of the relaxation process is set to a smaller value than the write threshold to facilitate writing. Thereby, the process of reducing the number of writes to the nonvolatile memory in the relaxation process is smaller than the process of reducing the number of writes to the nonvolatile memory in the write restriction process. Although the effect of functional deterioration (stopping memory writing) during the product life is reduced, the functionality of the engine control device can be maintained.

Still another computer of the present disclosure stores the number of writes to the nonvolatile memory after the previous write was completed, and detects the current number of writes to the nonvolatile memory. The write restriction process is a process of reducing the number of writes to the nonvolatile memory based on the write limit number, which is the difference between the number of writes after the previous write to the nonvolatile memory and this time. In addition, the relaxation process is a process in which the reduction in the number of writes to the nonvolatile memory is relaxed by a relaxation process count that is less frequent than the write limit count of the write restriction process. That is, the number of times of relaxation processing in the relaxation processing is set to a larger value than the number of processing timings of write restriction processing. Thereby, the process of reducing the number of writes to the nonvolatile memory in the relaxation process is smaller than the process of reducing the number of writes to the nonvolatile memory in the write restriction process. Although the effect of functional deterioration (stopping memory writing) during the product life is reduced, the functionality of the engine control device can be maintained.

Still another computer of the present disclosure determines whether the actual write value is less than or equal to the guaranteed number of write times with respect to the maximum guaranteed number of writes, and whether the usage time of the engine control device is less than or equal to the guaranteed number of times with respect to the assumed product life period. to decide. Further, another computer performs write restriction processing when at least one of the guaranteed number of times ratio and the guaranteed period ratio exceeds the ratio. On the other hand, still another computer performs a relaxation process that is more relaxed than the write restriction process unless both the guaranteed number of times ratio and the guaranteed period ratio exceed the ratios. When at least one of the guaranteed number of times ratio and the guaranteed period ratio exceeds the percentage, write restriction processing is performed, thereby making it easier to perform write restriction processing. This makes it easier to obtain the effect of functional deterioration (stopping memory writing) during the product life.

Still another computer of the present disclosure also determines whether the actual write value is less than or equal to the guaranteed number of writes with respect to the maximum guaranteed number of writes, and whether the usage time of the engine control device is less than or equal to the guaranteed number of times with respect to the assumed product life period. Deciding. Further, other computers perform write restriction processing when both the guaranteed number of times ratio and the guaranteed period ratio exceed the percentages, and are relaxed from the write restriction processing when at least one of the guaranteed number of times percentage and the guaranteed period percentage does not exceed the percentages. Perform mitigation treatment. Opportunities for mitigation processing are increased by performing mitigation processing unless at least one of the guaranteed number of times ratio and the guaranteed period ratio exceeds the percentage. The process prioritizes maintaining the functionality of the engine control device.

FIG. 1 is a system configuration diagram of an engine control device. FIG. 2 is a diagram showing the relationship between the assumed product life and the maximum guaranteed number of writes. FIG. 3 is a flowchart of advance notice flag processing. FIG. 4 is a flowchart of write execution processing and write restriction processing. FIG. 5 is a diagram showing a memory map of nonvolatile memory. FIG. 6 is a timing chart of write execution processing and write restriction processing. FIG. 7 is a flowchart of write restriction processing. FIG. 8 is a flowchart of another example of write restriction processing. FIG. 9 is a flowchart of still another example of write restriction processing. FIG. 10 is a timing chart of relaxation processing and write restriction processing using the guaranteed number of times ratio. FIG. 11 is a flowchart of the relaxation process and the write restriction process using the guaranteed number rate. FIG. 12 is a timing chart of another example of the relaxation process and the write restriction process using the guaranteed number rate. FIG. 13 is a flowchart of the mitigation process. FIG. 14 is a timing chart of still another example of the relaxation process and the write restriction process using the guaranteed number of times ratio. FIG. 15 is a flowchart of another example of the mitigation process. FIG. 16 is a flowchart of yet another example of the mitigation process. FIG. 17 is a flowchart of yet another example of the mitigation process. FIG. 18 is a timing chart of relaxation processing and write restriction processing using the guaranteed period ratio. FIG. 19 is a flowchart of relaxation processing and write restriction processing using the guaranteed period ratio. FIG. 20 is a timing chart of the relaxation process and the write restriction process using the number of times guaranteed rate and the period guaranteed rate. FIG. 21 is a flowchart of relaxation processing and write restriction processing using the guaranteed number of times ratio and guaranteed period ratio. FIG. 22 is a flowchart of another example of the relaxation process and write restriction process using the guaranteed number of times ratio and guaranteed period ratio.

Hereinafter, an example of the present disclosure will be described based on the drawings. As shown in FIG. 1, engine control device 100 includes a control section 110 and a drive circuit 120. The control unit 110 includes a computer 111, a nonvolatile memory 112, and a volatile memory 113.

Input signals from various sensors 130 are input to the drive circuit 120 . As the sensor 130, for example, there is a crank angle sensor 131 that detects the position of a crankshaft of an engine (not shown). With the input signal from this crank angle sensor 131, the position of the engine piston and the engine rotation speed can be detected.

As the sensor 130, there is a throttle opening sensor 132 that detects the opening of a throttle valve disposed in an intake passage of an engine (not shown). The input signal from the throttle opening sensor 132 can be used to measure the amount of intake air while the engine is rotating. Furthermore, the opening of the throttle valve when the engine is idling can be detected using a signal from the throttle opening sensor 132.

Sensor 130 also includes an ignition switch 133 that directs ignition of the engine. When the ignition switch 133 is turned on, a signal to start engine rotation is input to the drive circuit 120. Then, when the ignition switch 133 is turned off, an engine stop signal is input to the drive circuit 120.

The sensor 130 also includes an oxygen concentration sensor 134. The oxygen concentration sensor 134 is disposed in an exhaust passage of an engine (not shown) and measures the oxygen concentration in the exhaust gas. Along with the oxygen concentration sensor 134, the sensor 130 also includes a NOx detection sensor that detects the concentration of nitrogen oxides in the exhaust gas.

Further, the sensor 130 also includes an occupant operation signal input from the touch panel 135 of the meter. Instruction information from the crew includes cruise control speed and mode. Further, information from the touch panel 135 also includes information about quick shifts employed in motorcycles. However, in motorcycles, the touch panel 135 is not used, and a switch installed near the handlebar is often operated. In this example, the sensor 130 includes operation signals from the occupant including such switches. In addition, the sensor 130 includes various other sensors 136.

Further, the drive circuit 120 outputs drive signals to various actuators 140. The actuator 140 also includes various devices. For example, the actuator 140 includes an injector 141 that injects fuel into the engine, and an ignition coil 142 that burns the fuel and air taken into the engine. The actuator 140 also includes a throttle control motor 143 that actually varies the opening degree of the throttle valve. Further, the above-mentioned meter is also included in the actuator 140 as a display 144 that shows various conditions to the occupant. Various other actuators 145 also exist.

As engine control, for example, in idle speed control learning control, a predetermined idling state is determined based on the engine rotational speed from the crank angle sensor 131 and the throttle valve opening signal from the throttle opening sensor 132. This idling state also changes depending on the engine load, such as the engine temperature and the air conditioning condition of the vehicle. Then, the throttle control motor 143 is driven to achieve the determined idling state. Based on the engine rotational speed signal from the crank angle sensor 131 and the signal from the throttle opening sensor 132, it is confirmed whether the throttle control motor 143 is driven to the expected idling state. If there is a difference between the assumed engine speed and the actual engine speed, the throttle valve opening degree is corrected and the difference (correction amount) is learned.

Similarly, the throttle fully closed angle learning control regarding the opening degree of the throttle valve is also included in the engine control. The position when the throttle valve is fully closed is learned using the signal from the throttle opening sensor 132, and is used to correct mechanical positional deviation of the throttle valve. Based on the learned sensor signal value of the throttle opening sensor 132 at the throttle valve fully closed position, it is determined whether the throttle valve is correctly controlled to the fully closed position. A predetermined amount of intake air is allowed to pass through so that evacuation driving can be performed in case of a failure of the engine control device 100. Even during this evacuation drive, the throttle valve is controlled based on the learned fully closed position.

The data necessary to perform the above-described feedback control includes, for example, a learning value obtained by learning the deviation of actual measurement from prediction. Such data is then stored in nonvolatile memory 112. There are many other types of data stored in nonvolatile memory 112 when engine control device 100 performs engine control. For example, the target vehicle speed when performing cruise control is stored in the nonvolatile memory 112. Additionally, cruise control driving mode information is also stored in the nonvolatile memory 112. The driving mode information is input from the drive circuit 120 to the control unit 110 through communication using the in-vehicle CAN, such as switch operation information from the touch panel 135 of the meter. In addition to the cruise control mode, the driving mode information includes settings for the quick shift function, etc.

The data stored in the non-volatile memory 112 includes, for example, a failure mode OBD diagnosis history. The failure mode OBD includes a failure history, freeze frame data that stores the engine state at the time of abnormality detection, and information on the illumination of the failure warning light MIL. Furthermore, the data stored in the non-volatile memory 112 also includes total mileage information.

Here, the nonvolatile memory 112 has a maximum guaranteed number of write operations A that guarantees normal write operation. Although the maximum guaranteed number of writes A varies depending on the capacity of the nonvolatile memory 112, the usage environment, etc., the maximum guaranteed number of writes A is usually set from several hundred thousand times to over one million times. Further, an expected product life period B is also determined for the engine control device 100 including the sensor 130 and the actuator 140. Although this assumed product life period B also varies depending on the usage environment including the destination of the engine control device 100, a period of ten years or more is usually set as the assumed product life period B. In other words, the engine control device 100 is designed to operate normally during this assumed product life period B.

Figure 2 shows the relationship between the maximum guaranteed number of writes A of the non-volatile memory 112 and the expected product life period B of the engine control device 100. In Figure 2, the vertical axis shows the cumulative number of writes to the non-volatile memory 112, and the horizontal axis shows the usage time of the engine control device 100.

The computer 111 determines the upper limit value X of use, which indicates the upper limit number of times per hour of use of the engine control device 100, from the maximum guaranteed number of writes A of the non-volatile memory 112 for the expected product life period B of the engine control device 100. The value X0 of this upper limit value X at the start of use (t = 0) is set to 5% of the maximum guaranteed number of writes A. The slope of the upper limit value X of use is determined by drawing a straight line from this starting point X0 to the maximum guaranteed number of writes A. However, the upper limit value X of use does not allow up to the maximum guaranteed number of writes A. 95% of the maximum guaranteed number of writes A is set to the allowable upper limit value Xmax of the upper limit value X of use. In other words, the upper limit value X of use increases over time up to the allowable upper limit value Xmax, but after reaching the allowable upper limit value Xmax, it becomes a constant value. As described later, the number of times the non-volatile memory 112 is used is recorded in the non-volatile memory 112 itself. In addition, the period of use of the engine control device 100 is calculated using the calendar function of the control unit 110.

The system or device that provides the engine control device 100 and the computer 111 includes an electronic controller. The controller includes at least one processor circuit. One example of a processor circuit is a processor circuit that executes a program as a collection of multiple instructions. The processor circuit is a so-called microprocessor, and is provided as a chip. The controller includes a non-transitory, substantial recording medium that records the program and data. The processor circuit provides the function of the device according to this disclosure by executing the program. Another example of a processor circuit is a processor circuit that includes multiple logic circuits or analog circuits. The multiple logic circuits or analog circuits are configured with multiple physical elements and their electrical connections so as to provide the function of the device according to this disclosure. The processor circuit has various names such as an accelerator, a gate array, and an FPGA (field-programmable gate array). The controller is also called a microcontroller or a microcomputer.

Therefore, the computer 111 can count the number of actual writes to the nonvolatile memory 112 and create an actual write value Y indicating the actual number of writes per hour of use of the engine control device 100. In addition, the computer 111 also determines an ideal write value Z that is less than the upper limit value X of use. The width between the ideal write value Z and the upper limit for use X is determined depending on the usage environment including the destination of the engine control device 100. For example, for the ideal write value Z, the number of writes is reduced by about 5 to 15% than the use upper limit value X. Therefore, the value of Z0 at the start of use of the ideal write value Z (t=0) is 0, and the value of Zend at the end of use (t=B) is 85 to 95% of the maximum guaranteed number of writes A.

Next, writing frequency determination P200 of the computer 111 will be explained based on FIG. 3. The computer 111 first performs a write frequency determination P200 before performing a write process P210, which will be described later. In the write frequency determination P200, a preview comparison step P201 is performed to compare whether the actual write value Y exceeds the ideal write value Z. If the actual write value Y is equal to or less than the ideal write value Z (No), the process advances to write process P210. Conversely, if the actual write value Y exceeds the ideal write value Z (Yes), a notice step P202 is performed in which the notice flag is turned on, and then the process proceeds to write processing P210. The actual written value Y may exceed the ideal written value Z, for example, if the engine is turned on and off more than expected, or if the sensor 130 is not stable for some reason and a signal greater than expected is input. sell.

Note that the advance notice step P202 is also indicated as P202 in FIG. 2 as a point in time when the actual written value Y exceeds the ideal written value Z. When the advance notice flag is turned on, the notice flag is displayed on the meter display 144. This allows the occupant to recognize that more data has been written to the nonvolatile memory 112 than usual. However, since this is a warning, it may be displayed in a manner that can be distinguished from a warning flag, which will be described later, by, for example, turning on only when the engine is started.

A flowchart of the write process P210 is shown in FIG. In this write process P210, first, an on-determination P211 is performed to determine whether or not the advance notice flag is on. If the notice flag is not on (No), the actual write value Y does not exceed the ideal write value Z, and therefore the write execution process P212 is performed as is. Every time write execution processing P212 is performed, increment processing P213 is performed to add the current number of writes. However, the writing of this increment process P213 may be performed when the engine is stopped, such as in idle speed control learning control ISC, or may be performed while the engine is running in other cases.

When the notice flag is on (Yes), a warning comparison step P214 is performed to compare whether the actual written value Y exceeds the upper limit value X for use. If the actual write value Y is equal to or less than the use upper limit value X (No), the above-mentioned write execution process P212 is performed. Conversely, if the actual write value Y exceeds the usage upper limit value X (Yes), a warning step P216 is performed in which the warning flag is turned on, and a write restriction process P215 is performed. The write restriction process P215 will be described later. The flowchart ends by performing increment processing P213 or write restriction processing P215 (P220).

The timings of the write restriction process P215 and the warning step P216 are also shown in FIG. 2 using the same reference numerals. When the warning flag is turned on, the warning flag is displayed on the meter display 144. This allows the passenger to recognize that the write restriction process P215 has started.

Next, write restriction processing P215 will be explained using the timing chart shown in FIG. 6 and the flowchart shown in FIG. 7. For example, in the case of the idle speed control learning control ISC, learning is started from the time when the engine rotation starts (L100). The start of engine rotation (L100) is determined based on the input of a signal indicating that the ignition switch 133 is turned on. Then, the learned value changes depending on the operating condition of the engine (L101). If the learned value has changed when the engine is stopped (L102) compared to when the engine starts rotating (L100), it is written into the nonvolatile memory 112 (L103). As described above, writing is performed at the timing when the ignition switch 133 is turned off, indicating that the engine is stopped.

The writing of the learned value (L105) (L103) is determined based on whether there is a change, regardless of the magnitude of the change in the learned value. Therefore, the learned value (L105) from the second engine rotation start (L104) is also written if there is a change in the learned value at the second engine stop (L106) (L1030). The second writing (L1030) is performed regardless of the magnitude of the learning value (L101) from the first engine rotation start (L100) and the learning value (L105) from the second engine rotation start (L104). be exposed.

This is shown in the memory map of the nonvolatile memory 112 as shown in FIG. Of the data area 1120 of the nonvolatile memory 112, idle speed control learning control is controlled using data in an ISC control area 1121, and learning values are also written to this ISC control area 1121. Then, the information that writing was performed when the engine was stopped for the first time (L102) or when the engine was stopped for the second time (L107) is stored by incrementing the value of the write number storage area 1122 by one. As mentioned above, the maximum guaranteed write count A of this increment count is from several hundred thousand times to over one million times.

However, when the warning flag in warning step P216 is turned on as a result of the second writing (L1030), write restriction processing P215 is started. In the write restriction process P215, as shown in FIG. 7, writing to the nonvolatile memory 112 is determined based on whether or not the amount of change in the learned value exceeds a predetermined write threshold (D plus, D minus), rather than whether or not there is a change in the learned value. (Step P217). That is, it is determined whether the amount of change in the learned value in the positive direction exceeds the write threshold value D plus or the amount of change in the learned value in the negative direction exceeds the write threshold value D minus.

Note that the writing thresholds (D plus, D minus) are thresholds set in advance for each sensor 130 to limit writing. The value of the write threshold (D plus, D minus) differs depending on each sensor 130. The magnitudes of the writing threshold D plus in the positive direction and the writing threshold D minus in the negative direction are appropriately set according to conditions. Therefore, the absolute value of the write threshold D plus in the positive direction and the absolute value of the write threshold D minus in the negative direction may or may not match.

In FIG. 7, the amount of change in the learned value in the positive direction and the amount of change in the negative direction are both shown. Therefore, the write threshold D in FIG. 7 includes both the write threshold D plus in the positive direction and the write threshold D minus in the negative direction.

If the amount of change in the learned value (L108) from the third engine rotation start (L107), which is the point at which the write restriction process P215 is started, exceeds the write threshold D minus, the determination in step P217 becomes Yes, and the third time Write execution processing is performed (L110, P212) when the engine is stopped (L109). As described above, the value of the write count storage area 1122 is incremented by one (P213).

On the other hand, in the state where the write restriction process P215 has been started, if the amount of change in the learned value (L112) from the fourth engine rotation start point (L111) does not exceed the threshold value D plus, the determination in step P217 becomes No. In this case, even if there is a change in the learned value, no writing is performed when the engine is stopped for the fourth time (L113) (L114, P218). Therefore, the value in the write count storage area 1122 is not incremented. Therefore, when the engine starts rotating for the next fifth time (L115), the value used when the engine stops for the third time (L109) continues to be used. This is because as long as the write threshold value (D plus, D minus) is not exceeded, the influence on engine control is not large and is acceptable as engine control.

However, if the subsequent amount of change in the learning value (L116) exceeds the threshold value D minus, the determination in step P217 becomes Yes. In this case, even during the write restriction process P215, the write execution process is performed at the next fifth engine stop (L117) (L118, P212). As a result, the value in the write count storage area 1122 is incremented by one (P213). The flowchart ends with this increment processing P213 or processing P218 that does not perform writing (P220).

Then, in the warning comparison step P214, if the actual written value Y is equal to or less than the upper limit value for use Return to speed control learning control ISC. Therefore, if there is a change in the learned value (L120) when the engine is stopped for the sixth time (L121), a write execution process is performed to the nonvolatile memory 112 (L122, P212), and the current write count is incremented (P213). , the flowchart ends (P220).

Although the idle speed control learning control ISC has been described above, the write restriction process P215 corresponds to the input information from the sensor 130 described above and various engine controls based on the input information. Therefore, the write restriction process P215 is applied in descending order of the control or information that is written to the nonvolatile memory 112 the most times. This number of writes varies depending on the operating conditions of the engine, so it cannot be determined unconditionally. However, in the case of standard use, in the above example, oxygen concentration feedback learning, idle speed control learning control ISC, throttle full-close/opening learning, total travel distance, etc. correspond to controls and information that are written many times. Next, information that is written the most times includes cruise control target speed, driving mode information, and the like. Compared to these, failure mode OBD diagnosis history information is written fewer times.

However, the write restriction process P215 may be performed according to the priority of engine control, starting with the lowest priority control or information, rather than based on the number of writes. Among the above information, the failure mode OBD diagnostic history information has the highest priority, and therefore the write restriction process P215 for the failure mode OBD diagnostic history information is performed last. It is difficult to determine the priority of other controls or information, so they are ordered by the number of writes.

Note that although the above-mentioned example is a desirable example of the present disclosure, the present disclosure can be modified in various ways. For example, as the write restriction process P215, in the above example, if the write threshold value D was exceeded in the write restriction process P215, writing was executed regardless of the time. Alternatively, the write execution process (P212) may be performed only when the amount of change from the start of engine rotation exceeds the write threshold value D for a certain period of time or more. Thereby, the number of writes can be further suppressed in the write restriction process P215.

Furthermore, in the above example, in the warning comparison step P214 for comparing whether or not the actual written value Y exceeds the upper limit usage value The write threshold was used only in the restriction process P215. In the warning comparison step P214, if the actual write value Y does not exceed the upper limit of use X (No), it is determined whether or not to write even in normal conditions. The judgment may be made based on the following. In that case, the threshold value (write threshold D) used when performing write restriction processing P215 is made larger than the value of the threshold value (relaxed threshold value) during normal times, and the restriction is relaxed from write restriction processing P215 during normal times. It is desirable to use a mitigation process that An example of this relaxation process will be described later.

In addition, in the above example, the number of writes and learned value that was incremented when the engine was stopped last time are memorized, and the number of writes and learned value that was incremented when the engine was stopped last time are stored, and the next time the write is performed based on the previous memorized value and the number of writes and learned value that was incremented when the engine was stopped this time. It was determined whether or not to perform the restriction process P215. The number of times of writing and the learned value at the start of the current engine operation may be stored. It may be determined whether or not to perform the write restriction process P215 next time by comparing the stored value at the start of the current operation with the number of writes or learned value incremented at the time of the engine stop this time.

Another example of this write restriction process P215 will be explained using the flowchart of FIG. 8. As described above, the write count storage area 1122 of the nonvolatile memory 112 stores the write count after the previous write is completed. The computer 111 detects the current number of writes to the nonvolatile memory 112 and calculates the difference between the number of writes to the nonvolatile memory 112 after the previous write and the number of writes after the current write.

Then, when the write restriction process P215 is started, it is determined whether the difference between the calculated number of writes to the nonvolatile memory 112 after the previous write and the current number of writes is greater than a predetermined write limit number K. (Step P219). That is, another example of the write restriction process P215 is performed based on the write limit number K, which is the difference between the number of times after the previous write to the nonvolatile memory 112 and this time. If the difference in the number of writes between the learned values is greater than the limited number of writes K (Yes), the write is limited and the write frequency is reduced. Conversely, if the difference in the number of writes between the learned values is not greater than the limited number of writes K (No), no write restriction is performed.

For example, if the write limit number K is set to 5 times, up to 5 times is not greater than the write limit number K (No), so writing is performed and the value in the write number storage area 1122 is incremented by 1 (P213). On the other hand, if the difference in the number of writes of the learning value is 6 times, which is greater than the write limit number K (Yes), the write execution process is not performed (P218). Thereby, the number of writes can be suppressed in the write restriction process P215. Then, the flowchart ends with processing P218 in which no writing is performed or increment processing P213 (P220).

Furthermore, when the engine is started and stopped very frequently, the number of writes may not be incremented every time the engine is stopped, but may be incremented once every several times. Alternatively, the number of writes may be incremented when the engine is stopped after the engine has been operated for a predetermined period of time or more.

Among other examples of the write restriction process P215, the former example in which the write restriction process P215 is performed in accordance with the number of times the engine is stopped will be explained using the flowchart of FIG. In the case of write processing P210, the number of writes incremented each time the engine is stopped is stored in the number of writes storage area 1122 of the nonvolatile memory 112. In contrast, in this example, in step P230, it is determined whether the number of engine stops when the write execution process (P212) is performed while the engine is running exceeds a predetermined number of write stops M (P230).

Only when the number of engine stops is greater than the number of write stops M (Yes), write execution processing P212 is performed, and the value in the write number storage area 1122 is incremented by one (P213). If the number of engine stops is less than the number of write stops M (No), the write execution process is not performed (P218). Thereby, the number of writes can be suppressed in the write restriction process P215. The flowchart is ended (P220) by the process P218 without writing or the increment process P213, as in the example of FIG. 7 or FIG.

Further, in the above example, the display 144 of the meter displayed that the advance notice flag or the warning flag was turned on. This is desirable to inform the crew of the situation. However, on the other hand, it means presenting more information to the occupants, which may make them feel uncomfortable. Therefore, the information that the advance notice flag and the like are turned on may be stored only within the engine control device 100 and may not be displayed on the display 144. Warning flags may also be handled in the same way. That is, information indicating that a warning flag or the like is turned on may be stored only within the engine control device 100, or may be notified to an external terminal through a communication means, but not displayed on the display 144. Even if the occupant is not notified, by performing the write restriction process P215, it is possible to prevent writing to the nonvolatile memory 112 exceeding the limit number of times.

Furthermore, in the above example, before the warning flag is turned on, a preview step P202 is performed to determine whether the warning flag will be turned on. It is desirable to be able to grasp the situation in advance. However, the control flowchart may become redundant. Therefore, it is also possible to abolish the advance notice step P202. Particularly, as described above, when the information with the preview flag turned on is not displayed on the display 144, eliminating the preview step P202 has little effect.

Next, the relaxation process will be explained. In the example shown in FIG. 2, the write restriction process P215 of the nonvolatile memory 112 is performed for the entire period from immediately after the start of use until the maximum guaranteed number of times is reached. This is a desirable process for limiting the number of writes. On the other hand, in the engine control device 100, for example, in the case of idle speed control learning control ISC, the learning function is limited, so there is a possibility that accurate control cannot be performed. Therefore, as shown in the time chart of FIG. 10 and the flow chart of FIG. 11, it is determined whether the actual write value Y is less than or equal to the guaranteed number of times ratio A1 for the maximum guaranteed number of writes A (step P221). Also good. If the actual write value Y is less than the guaranteed number of times ratio A1 (No), a relaxation process P222 that is more relaxed than the write restriction process P215 is performed. Then, the write restriction process P215 may be started after the actual write value Y becomes greater than the guaranteed number of times ratio A1 (Yes).

In the example of FIG. 10, even if the actual write value Y exceeds the usage upper limit value X, if the actual write value Y is less than the guaranteed number of times ratio A1, the write restriction process P215 is not performed. The write restriction process P215 is performed after the actual write value Y reaches the guaranteed number of times ratio A1. The guaranteed number of times ratio A1 is about 30% to 70% of the maximum guaranteed number of writes A, and is set depending on the usage environment including the destination of the engine control device 100. In the example of FIG. 10, not performing the write restriction process P215 is the relaxation process P222.

However, the relaxation process P222 is not limited to not performing the write restriction process P215 shown in FIG. As shown in the flowchart of FIG. 11, not performing the write restriction process P215 is one example, but it is also possible to adopt a relaxed threshold value E that is more relaxed than the write threshold value D, or to use a relaxed process number L that is more relaxed than the write limit number of times K. You may also adopt it. Further, the number of times the engine is stopped for performing the write process P210 may be set to the relaxed number of stop times N, which is more relaxed than the number M of write stops. As an example of using the number of engine stops, the write restriction process P215 may be performed only after the engine has been stopped a predetermined number of times (relaxation number R) in a state where the write restriction process P215 is required. Similarly, in the case where the write process P210 is performed only when the engine has been continuously operated for a predetermined time or more, the predetermined time may be set to be longer in the relaxation process P222 than the time in the write restriction process P215. In addition, various methods can be adopted as long as the processing can reduce the write execution processing P212. Furthermore, the relaxation process P222 may be performed by combining the relaxation threshold E, the number of times L of relaxation processing, and the like.

Among the examples illustrated in FIG. 11, an example using the relaxation threshold E, the number of times L of relaxation processing, the number N of relaxation stops, and the number of times R of relaxation will be described using a timing chart and a flowchart. The time chart in FIG. 12 and the flow chart in FIG. 13 are examples in which the relaxation threshold E is used. The relaxation threshold E of the relaxation process P222 is relaxed and smaller than the write threshold D of the write restriction process P215. More specifically, compared to the range from the write threshold D minus, which is the amount of change in the negative direction, to the write threshold D plus, which is the amount of change in the positive direction, the range from the relaxation threshold E minus, which is the amount of change in the negative direction, to the plus The range up to the relaxation threshold E plus, which is the amount of change in direction, is set to be small. Note that in FIG. 13 as well as in FIG. 7 described above, the relaxation threshold E represents the relaxation threshold E minus and the relaxation threshold E plus. In this example, writing to the nonvolatile memory 112 is performed under certain restrictions in both the relaxation process P222 and the write restriction process P215. However, writing to the nonvolatile memory 112 in the relaxation process P222 is performed more frequently than writing to the nonvolatile memory 112 in the write restriction process P215.

As shown in the time chart of FIG. 12, when the actual write value Y is less than the guaranteed number of times ratio A1, the relaxed threshold E is adopted. Then, when the actual write value Y exceeds the guaranteed number of times ratio A1, the threshold value is changed from the relaxed threshold value E to the write threshold value D. The relaxation process P222 will be explained using the flowchart of FIG. 13. In step P223, it is determined whether the amount of change in the learning value exceeds the relaxation threshold E. Note that, like the write threshold D, this relaxation threshold E is also a threshold value in a positive direction and a negative direction. The degree to which the relaxation threshold E is to be relaxed from the write threshold D is also determined depending on the usage environment including the destination.

If the amount of change in the learning value exceeds the relaxation threshold E in step P223 (Yes), a write execution process is performed when the engine is stopped (P212). As a result, the value in the write count storage area 1122 is incremented by one (P213). On the other hand, if the amount of change in the learning value does not exceed the relaxation threshold E in step P223 (No), no writing is performed even if there is a change in the learning value (P218). The flowchart ends P220 by the process P218 in which no writing is performed or the increment process P213.

Next, when using the write limit number of times K as shown in FIG. 8 as the write limit process P215, an example will be described in which a relaxed process number L, which is a condition relaxed from the write limit number of times K, is used. As shown in the time chart of FIG. 14 and the flowchart of FIG. 15, the number of times L of relaxation processing in the relaxation processing P222 is relaxed and larger than the number of times K of writing restrictions in the writing restriction processing P215. In this example as well, similar to the example shown in the time chart of FIG. 12 and the flowchart of FIG. 13, writing to the nonvolatile memory 112 is performed under certain restrictions in the relaxation process P222. The restrictions on writing to the nonvolatile memory 112 in the relaxation process P222 are set to conditions that are more relaxed than the restrictions on writing to the nonvolatile memory 112 in the write restriction process P215. As a result, the write execution process (P212) becomes more frequent. For example, when the write limit number K is 5 times, the relaxed limit number L is set to 8 times, and writing is performed up to 8 times.

As shown in the time chart of FIG. 14, when the actual write value Y is less than the guaranteed number of times ratio A1, the number of times of relaxation processing L is adopted. At timing L0, the actual write value Y is less than the usage upper limit value X, so it is not subject to the write restriction process P215 in the first place. Therefore, at timing L0, a write execution process is performed when the engine is stopped (P212), and the value in the write count storage area 1122 is incremented by one (P213).

However, at timings L1, L2, and L3, the actual write value Y is greater than the usage upper limit value X, so it is subject to the write restriction process P215. Therefore, at these timings L1, L2, and L3, when the predetermined number of times L of relaxation processing is exceeded, write execution processing P212 is performed. Then, when the actual write value Y exceeds the guaranteed number of times ratio A1, the number of times required to perform the write execution process P212 is changed from the relaxed process number L to the write limit number K.

The relaxation process P222 of this example will be explained using the flowchart of FIG. 15. In step P224, it is determined whether the number of times the learning value is written exceeds the number L of relaxation processing. If the number of times the learning value is written does not exceed the number of times of relaxation processing L in step P224 (No), a write execution process is performed (P212), and the value in the number of writes storage area 1122 is incremented by one (P213). On the other hand, if the number of times the learned value is written exceeds the number L of relaxation processing in step P224 (Yes), no writing is performed even if there is a change in the learned value (P218). The flowchart ends with processing P218 in which no writing is performed or increment processing P213 (P220).

Next, as another example of the write restriction process P215, an example will be described in which the number of times the engine is stopped when the write execution process (P212) is performed while the engine is running as shown in FIG. 9 is used. In this case, the relaxed number of stoppages N, which is a more relaxed condition than the number of write stoppages M, is used. The relaxation stop count N of the relaxation process P222 is smaller than the write stop count M of the write restriction process P215. For example, if the number of engine stops when the write execution process (P212) is performed while the engine is running in the write restriction process P215 is set to 3 (number of write stops M = 3), the number of relaxed stops N is set to 2. , the frequency of write execution processing (P212) is increasing. In this example, as in the above example, writing to the nonvolatile memory 112 is performed under certain restrictions in the relaxation process P222. The conditions for writing to the nonvolatile memory 112 in the relaxation process P222 are more relaxed than those for writing to the nonvolatile memory 112 in the write restriction process P215.

The relaxation process P222 in this example is shown in the flowchart of FIG. In step P225, it is determined whether the number of engine stops exceeds the number of relaxation stops N. If the number of engine stops exceeds the number of relaxed stops N in step P225 (Yes), a write execution process is performed (P212), and the value in the number of write times storage area 1122 is incremented by one (P213). If the number of engine stops does not exceed the number of relaxation stops N in step P225 (No), no writing is performed even if there is a change in the learned value (P218). The flowchart is ended (P220) by the process P218 in which no writing is performed or the increment process P213 (P220), as in the above example.

As a method of relaxing the write restriction process P215 based on the number of times the engine is stopped, it is also possible to combine the amount of change in the learned value shown in FIG. 7 or the number of times the learned value is written and the number of engine stops shown in FIG. be. If the actual write value Y is less than the guaranteed number of times ratio A1, even if the amount of change in the learned value exceeds the write threshold D or the number of times the learned value is written exceeds the write limit number K, the engine operation The write restriction process P215 is not performed unless the start/stop cycle continues for the relaxation number R or more. The number of times R of relaxation is set such that, for example, the number of times R of relaxation is reached when the cycle of starting and stopping the engine is repeated three times. Then, when the actual write value Y exceeds the guaranteed number of times ratio A1, the write restriction process P215 is performed every time the engine is stopped.

Control in this example will be explained using the flowchart of FIG. 17. In step P226, it is determined whether the number of times the engine is stopped for write restriction processing P215 exceeds the number of relaxation times R. If the number of times the engine is stopped exceeds the number of relaxation times R in step P226 (Yes), write restriction processing P215 is performed to restrict writing. On the other hand, if the number of engine stops that results in write restriction processing P215 in step P226 does not exceed the relaxation number R (No), writing restriction is not performed even in the state of write restriction processing P215. That is, a write execution process is performed (P212), and the value in the write count storage area 1122 is incremented by one (P213). Then, the flowchart ends with this write restriction processing P215 or increment processing P213 (P220).

Note that, as described above, the write restriction process P215 may be performed not when the engine operation ends, but when the engine operation starts. Therefore, the number of engine stops in the present disclosure also includes the number of times the engine starts operating.

In the timing chart shown in FIG. 10 and the flowchart shown in FIG. 11, it is determined whether or not to perform the relaxation process P222 depending on whether the actual write value Y exceeds the guaranteed number of times ratio A1. This is a judgment based on the actual number of uses, which is desirable. However, as shown in the timing chart of FIG. 18, it is possible to use the actual usage time T instead of the actual write value Y. In this case, in step P227 of the flowchart of FIG. 19, it is determined whether the actual usage time T exceeds the guaranteed period ratio B1. This period guarantee ratio B1 is approximately 30% to 70% of the assumed product life period B, and is appropriately set depending on the usage environment including the destination of the engine control device 100. Then, in step P227, if the actual usage time T does not exceed the guaranteed period ratio B1 (No), the relaxation process P222 is performed. This relaxation process P222 is similar to the flowchart in FIG. 11, and includes various controls as shown in FIGS. 13, 15, 16, and 17.

Furthermore, as shown in FIG. 20, the relaxation process P222 is performed by combining the determination of whether the actual write value Y exceeds the guaranteed number of times ratio A1 and the determination of whether the actual usage time T exceeds the guaranteed period ratio B1. You may decide whether or not to do so. In this case, there may be a decision to give priority to the relaxation process P222 or a decision to give priority to the write restriction process P215.

The flowchart in FIG. 21 is a control that gives priority to the relaxation process P222. If the actual write value Y does not exceed the guaranteed number of times ratio A1 in step P221 (No), or if the actual usage time T does not exceed the guaranteed period ratio B1 in step P227 (No), the relaxation process P222 is performed. The write restriction process P215 is performed only when both step P221 and step P227 are YES. By prioritizing the mitigation process P222, the accuracy of the engine control device 100 can be improved.

The flowchart in FIG. 22 is, on the contrary, a control that gives priority to write restriction processing P215. If the actual write value Y exceeds the guaranteed number of times ratio A1 in step P221 (Yes), or if the actual usage time T exceeds the guaranteed period ratio B1 in step P227 (Yes), the write restriction process P215 is performed. Therefore, the relaxation process P222 is performed only when both step P221 and step P227 are No. By making it easier to perform the write restriction process P215, it is easier to obtain the effect of functional deterioration (memory write stop) during the product life.

Further, in the present disclosure, writing to the nonvolatile memory 112 is performed according to the operation of the engine, but the engine of the present disclosure is not limited to an internal combustion engine. Hybrid drive or motor drive is also possible. The engine in this disclosure is a general term for the driving force of a vehicle in general.

Disclosure of Technical Ideas This specification discloses technical ideas described in the sections listed below. Some sections may be written in a multiple dependent form, in which subsequent sections alternatively cite preceding sections. Additionally, some terms may be written in a multiple dependent form referring to another multiple dependent form. The terms written in these multiple dependent forms define multiple technical ideas.

(Technical thought 1)
a nonvolatile memory that has a data storage area and allows data to be written and erased, and has a write count storage area that stores the write count;
An engine control device comprising a computer that writes to and reads from this nonvolatile memory,
The computer determines an upper limit usage value indicating the upper limit number of times per usage period of the engine control device based on the maximum guaranteed number of writes guaranteed by the nonvolatile memory for the assumed product life period of the engine control device,
The computer counts the number of actual writes to the nonvolatile memory and creates an actual write value indicating the actual number of writes per period of use of the engine control device,
The engine control device is characterized in that, when the computer determines that the actual write value exceeds the upper limit for use by a predetermined value or more, the computer performs write restriction processing to reduce the number of writes to the nonvolatile memory.

(Technical thought 2)
The engine control device according to technical concept 1, wherein the computer cancels the write restriction process when determining that the actual written value is lower than the upper limit value by a predetermined value or more due to the write restriction process.

(Technical thought 3)
Technical idea 1 or 2, characterized in that the write restriction process is a process in which a write threshold for restricting writing is set in advance, and the number of writes to the nonvolatile memory is reduced using this write threshold. The engine control device described in .

(Technical thought 4)
The computer creates an ideal write value in which the number of writes is less than the upper limit value,
The engine control device according to any one of technical ideas 1 to 3, wherein when it is determined that the actual written value exceeds the ideal written value, it is determined whether or not to give advance notice to perform the write restriction processing. .

(Technical Thought 5)
The computer performs control of a plurality of groups classified by engine control function, and the write restriction process is applied in descending order of the number of writes among the control groups of the plurality of groups. 4. The engine control device according to any one of 4.

(Technical Thought 6)
The computer controls a plurality of groups classified by engine control function, and the write restriction process is applied in order of priority for engine control among the plurality of groups. The engine control device according to any one of technical ideas 1 to 5.

(Technical Thought 7)
The computer stores the number of writes to the non-volatile memory after the last write is completed, and detects the number of writes to the non-volatile memory after the current write ends,
The write restriction process is a process of reducing the number of writes to the non-volatile memory based on a write limit number, which is the difference between the number of writes after the previous write to the non-volatile memory and after the current write. The engine control device according to any one of technical ideas 1 to 6, characterized in that:

(Technical Thought 8)
The engine control device further includes a display that shows the operating status of the computer to a user,
8. The engine control device according to any one of technical ideas 1 to 7, wherein the computer outputs a warning flag to the display to indicate that the write restriction process is to be performed.

(Technical Thought 9)
According to technical idea 4, when it is determined that the actual written value exceeds the ideal written value, a notice flag is output to the display to indicate that the actual written value exceeds the ideal written value. The engine control device according to Technical Idea 8.

(Technical Thought 10)
The computer determines whether the actual write value exceeds a guaranteed number of times ratio with respect to the maximum guaranteed number of writes;
The computer performs the write restriction process when the actual write value exceeds the guaranteed number of times ratio,
The engine control device according to any one of technical ideas 1 to 9, wherein the computer performs a relaxation process that is more relaxed than the write restriction process if the actual write value does not exceed the guaranteed number of times ratio.

(Technical Thought 11)
The computer determines whether the actual operating time of the engine control device exceeds a guaranteed period ratio with respect to the assumed product life period;
The computer performs the write restriction process when the actual usage time exceeds the guaranteed period ratio;
The engine control device according to any one of technical ideas 1 to 9, wherein the computer performs a relaxation process that is more relaxed than the write restriction process if the actual usage time does not exceed the guaranteed period ratio.

(Technical Thought 12)
The engine control device according to Technical Idea 10 or 11, wherein the relaxation process makes the write restriction process fail.

(Technical Thought 13)
The engine control device according to technical idea 10 or 11, wherein the relaxation process makes the write restriction process fail until the write restriction process continues a number of times of relaxation.

(Technical Thought 14)
The write restriction process is a process in which a write threshold for restricting writing is set in advance, and the write threshold is used to reduce the number of writes to the nonvolatile memory,
According to technical idea 10 or 11, the relaxation process is a process of relaxing the reduction in the number of writes to the nonvolatile memory using a relaxation threshold that is more relaxed than the write threshold of the write restriction process. engine control device.

(Technical Concept 15)
The computer stores the number of writes to the non-volatile memory since the end of a previous write,
a current number of writes to the nonvolatile memory is detected, and the write limiting process is a process of reducing the number of writes to the nonvolatile memory based on a write limit number that is a difference between the number of writes to the nonvolatile memory after the end of a previous write and the number of writes to the nonvolatile memory;
The engine control device according to Technical Idea 10 or 11, characterized in that the mitigation process is a process of mitigating the reduction in the number of writes to the non-volatile memory by a mitigation process count that is more mitigated than the write limit count of the write restriction process.

(Technical Thought 16)
The computer determines whether the actual write value is less than or equal to the guaranteed number of writes with respect to the maximum guaranteed number of writes, and whether the usage time of the engine control device is less than or equal to the guaranteed number of times with respect to the assumed product life period. death,
The computer performs the write restriction process when at least one of the guaranteed number of times percentage and the guaranteed period percentage exceeds a percentage;
The engine according to any one of technical ideas 1 to 15, wherein the computer performs a relaxation process that is more relaxed than the write restriction process unless both the guaranteed number of times ratio and the guaranteed period ratio exceed the ratios. Control device.

(Technical Thought 17)
The computer determines whether the actual write value is less than or equal to the guaranteed number of writes with respect to the maximum guaranteed number of writes, and whether the usage time of the engine control device is less than or equal to the guaranteed number of times with respect to the assumed product life period. death,
The computer performs the write restriction process when both the guaranteed number of times percentage and the guaranteed period percentage exceed a percentage;
According to any one of technical ideas 1 to 15, the computer performs a relaxation process that is more relaxed than the write restriction process unless at least one of the guaranteed number of times ratio and the guaranteed period ratio exceeds the ratio. engine control device.

Claims (17)

a nonvolatile memory that has a data storage area and allows data to be written and erased, and has a write count storage area that stores the write count;
An engine control device comprising a computer that writes to and reads from this nonvolatile memory,
The computer determines a usage upper limit value indicating the upper limit number of times per usage period of the engine control device based on the maximum guaranteed number of writes guaranteed by the nonvolatile memory for the assumed product life period of the engine control device;
The computer counts the number of actual writes to the nonvolatile memory and creates an actual write value indicating the actual number of writes per period of use of the engine control device,
An engine control device characterized in that, when the computer determines that the actual write value exceeds the upper limit value for use by a predetermined value or more, the computer performs a write restriction process so as to reduce the number of writes to the nonvolatile memory. 2. The engine control device according to claim 1, wherein the computer cancels the write restriction process when it determines that the actual write value falls below the usage upper limit value by a predetermined value or more as a result of the write restriction process. 3. The write restriction process is a process in which a write threshold for restricting writing is set in advance, and the write threshold is used to reduce the number of writes to the nonvolatile memory. The engine control device described. The computer creates an ideal write value in which the number of writes is less than the upper limit value,
The engine control device according to claim 1 or 2, wherein when determining that the actual write value exceeds the ideal write value, it is determined whether or not to give advance notice to perform the write restriction process. 2. The computer controls a plurality of groups classified by engine control function, and the write restriction process is applied in descending order of the number of writes among the plurality of groups. The engine control device described in . The computer controls a plurality of groups classified by engine control function, and the write restriction process is applied in order of priority for engine control among the plurality of groups. The engine control device according to claim 1 or 2. The computer stores the number of writes to the non-volatile memory after the last write is completed, and detects the number of writes to the non-volatile memory after the current write ends,
The write restriction process is a process of reducing the number of writes to the non-volatile memory based on a write limit number, which is the difference between the number of writes after the previous write to the non-volatile memory and after the current write. The engine control device according to claim 1 or 2, characterized in that: The engine control device further includes a display that shows the operating status of the computer to a user,
The engine control device according to claim 1 or 2, wherein the computer outputs a warning flag to the display to indicate that the write restriction processing is to be performed. The computer creates an ideal write value in which the number of writes is less than the upper limit value,
When determining that the actual write value exceeds the ideal write value, determining whether or not to give advance notice to perform the write restriction process;
9. When it is determined that the actual written value exceeds the ideal written value, a notice flag is output to the display to indicate that the actual written value exceeds the ideal written value. Engine control device. The computer determines whether the actual write value exceeds a guaranteed number of times ratio with respect to the maximum guaranteed number of writes;
The computer performs the write restriction process when the actual write value exceeds the guaranteed number of times ratio,
The engine control device according to claim 1, wherein the computer performs a relaxation process that is more relaxed than the write restriction process if the actual write value does not exceed the guaranteed number of times ratio. The computer determines whether the actual operating time of the engine control device exceeds a guaranteed period ratio with respect to the assumed product life period;
The computer performs the write restriction process when the actual usage time exceeds the guaranteed period ratio;
The engine control device according to claim 1, wherein the computer performs a relaxation process that is more relaxed than the write restriction process if the actual usage time does not exceed the guaranteed period ratio. The engine control device according to claim 10 or 11, wherein the relaxation process causes the write restriction process to fail. The engine control device according to claim 10 or 11, wherein the relaxation process disables the write restriction process until the write restriction process continues a relaxation number of times. The write restriction process is a process in which a write threshold for restricting writing is set in advance, and the write threshold is used to reduce the number of writes to the nonvolatile memory,
12. The relaxation process is a process of relaxing the reduction in the number of writes to the non-volatile memory using a relaxation threshold that is more relaxed than the write threshold of the write restriction process. Engine control device. The computer stores the number of writes to the nonvolatile memory after the previous write was completed;
The current number of writes to the nonvolatile memory is detected, and the write restriction process is performed based on the write limit number, which is the difference between the number of writes after the previous write to the nonvolatile memory and the current number of writes to the nonvolatile memory. This is a process that reduces the number of writes to memory.
12. The relaxation process is a process for relaxing the reduction in the number of writes to the nonvolatile memory using a relaxation process count that is more relaxed than the write limit count of the write restriction process. The engine control device described. The computer determines whether the actual write value is less than or equal to the guaranteed number of writes with respect to the maximum guaranteed number of writes, and whether the usage time of the engine control device is less than or equal to the guaranteed number of times with respect to the assumed product life period. death,
The computer performs the write restriction process when at least one of the guaranteed number of times percentage and the guaranteed period percentage exceeds a percentage;
The engine control device according to claim 1, wherein the computer performs a relaxation process that is more relaxed than the write restriction process unless both the guaranteed number of times ratio and the guaranteed period ratio exceed a ratio. The computer determines whether the actual write value is less than or equal to the guaranteed number of writes with respect to the maximum guaranteed number of writes, and whether the usage time of the engine control device is less than or equal to the guaranteed number of times with respect to the assumed product life period. death,
The computer performs the write restriction process when both the guaranteed number of times percentage and the guaranteed period percentage exceed a percentage;
The engine control device according to claim 1, wherein the computer performs a relaxation process that is more relaxed than the write restriction process unless at least one of the guaranteed number of times ratio and the guaranteed period ratio exceeds the ratio.

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