JP7638830B2 - Vehicle control device - Google Patents

Description

The present invention relates to a vehicle control device that controls the storage of freeze frame data.

Conventionally, when a vehicle malfunction occurs, the CPU of an ECU (Electronic Control Unit) mounted on a vehicle stores freeze frame data (FFD, including, for example, coolant temperature information, engine RPM information, throttle opening information, vehicle speed information, fuel pressure information, intake temperature information, and malfunction cause information linked to these) in a non-volatile memory (for example, EEPROM). When the ECU's CPU starts up, it reads the freeze frame data from the non-volatile memory and stores it in a volatile memory (RAM), and at this time checks for data corruption using a data error detection method such as a mirror check or a sum check. When a diagnostic tool is connected to the ECU, the ECU's CPU reads the freeze frame data from the volatile memory in response to a request from the diagnostic tool and sends it to the diagnostic tool (for example, see Patent Document 1).

JP 2007-138726 A

However, because freeze frame data is large, it is divided and stored continuously across multiple sections of non-volatile memory.

In addition, because writing data to non-volatile memory takes a certain amount of time, writing a huge amount of freeze frame data to non-volatile memory can take a long time (e.g., several seconds). For this reason, there is a risk that the power supply will be cut off due to the battery being removed or a momentary interruption while the freeze frame data is being written to non-volatile memory.

If the power supply is interrupted while writing a freeze frame data to the non-volatile memory when a vehicle failure occurs, the writing of the freeze frame data to the non-volatile memory will be interrupted. In this case, part of the freeze frame data will be written to and stored in a corresponding section of the multiple sections of the non-volatile memory, but the remainder of the freeze frame data will not be written to and stored in the corresponding section of the multiple sections. In this case, if it is not possible to determine whether the data stored in each of the multiple sections is related to the freeze frame data, the vehicle failure will be analyzed including data unrelated to the freeze frame data, and an accurate analysis of the vehicle failure will not be possible.

The object of the present invention is to provide a vehicle control device that can prevent the problem of analyzing a vehicle fault including data that is not related to a single freeze frame data when a fault occurs in the vehicle.

In order to achieve the above object, the vehicle control device according to the present invention is a vehicle control device that controls the storage of freeze frame data when a vehicle failure occurs, and performs a write process in which, when a vehicle failure occurs, each of a plurality of section write data constituting one freeze frame data is written as failure information to a corresponding section of a plurality of sections in a non-volatile memory, and correlation data that is correlated to each of the plurality of sections is written as write confirmation information. In the write process, after writing of the section write data and the correlation data to one section is completed, the section write data and the correlation data are written to another section, and when reading the one freeze frame data from the non-volatile memory, it is characterized in that it includes a write means that determines whether the write confirmation information held in each of the plurality of sections is correlated with each other, and determines that the failure information held in the plurality of sections is information to be used for analyzing the vehicle failure if it is determined that the write confirmation information is correlated with each other, and does not determine that the write confirmation information is information to be used for analyzing the vehicle failure if it is not determined that the write confirmation information is correlated with each other.

According to this configuration, when a vehicle failure occurs and a freeze frame data is successfully written to the non-volatile memory, the write confirmation information stored in each of the multiple sections of the non-volatile memory is correlated with each other, whereas when a freeze frame data is not successfully written to the non-volatile memory due to a power supply interruption while the freeze frame data is being written to the non-volatile memory, there is no correlation between the write confirmation information stored in the section in which the section write data was successfully written and the write confirmation information stored in the section in which the section write data was not successfully written. Therefore, if there is no correlation between the write confirmation information stored in each of the multiple sections and other write confirmation information, it can be determined that the failure information stored in each of the multiple sections includes information unrelated to the freeze frame data, and the problem of analyzing the vehicle failure including information unrelated to the freeze frame data can be prevented.

In addition, by determining whether the write confirmation information stored in each of the multiple sections is correlated with each other, it is possible to determine whether the fault information stored in each of the multiple sections is related to a single freeze frame data, thereby shortening the time required for this determination.

The writing means may write the correlated correlation data currently written to each of the plurality of sections as the write confirmation information when a current vehicle failure occurs, to data that is not correlated with the correlated correlation data previously written to each of the plurality of sections as the write confirmation information when a previous vehicle failure occurred.

This prevents the problem of analyzing a vehicle failure using a mixture of freeze frame data from the current vehicle failure and freeze frame data from a previous vehicle failure.

The system may further include an erasing means for erasing the failure information and the write confirmation information stored in each of the multiple sections if it is determined that the write confirmation information is not correlated with each other.

This will further prevent future issues such as vehicle failure analysis using failure information stored in each of multiple sections of non-volatile memory when writing freeze frame data to non-volatile memory fails.

According to the present invention, when a vehicle failure occurs, each of the multiple section write data constituting one freeze frame data is written as failure information to a corresponding one of the multiple sections of the non-volatile memory, and correlation data that is correlated to each of the multiple sections is written as write confirmation information. Therefore, by determining whether the write confirmation information held in each of the multiple sections is correlated with each other, it is possible to determine whether the failure information held in each of the multiple sections is related to one freeze frame data, and the problem of analyzing a vehicle failure including information unrelated to one freeze frame data can be prevented. In this way, it is suitable for storing one freeze frame data divided across multiple sections of the non-volatile memory.

1 is a block diagram showing a configuration of a vehicle control system according to an embodiment of the present invention; 2 is a flowchart showing a process flow of freeze frame data (FFD) storage processing performed by a CPU of a main ECU in FIG. 1 . 2 is a flowchart showing a process flow of a freeze frame data (FFD) reading process performed by a CPU of a main ECU in FIG. 1 . 1A is a diagram for explaining an example of successful writing of freeze frame data to the data flash, and FIG. 1B is a diagram for explaining an example of unsuccessful writing of freeze frame data to the data flash. FIG.

The following describes in detail an embodiment of the present invention with reference to the accompanying drawings.

1. System Configuration of Vehicle Control System The configuration of a vehicle control system S according to an embodiment of the present invention will be described with reference to FIG.

The vehicle control system S is a system that is installed in the vehicle 1 and performs control related to the storage of freeze frame data (hereinafter, appropriately referred to as "FFD"), which will be described later, when a malfunction occurs in the vehicle 1, for example.

The vehicle control system S includes multiple ECUs, such as a main ECU 10 and ECUs 30, 50, and 70, which are connected to a bus 2 and communicate with the other ECUs via a controller area network (CAN). For example, the main ECU 10 periodically communicates with the ECUs 30, 50, and 70. Examples of the ECUs 30, 50, and 70 include an engine ECU that controls the engine throttle opening and engine stop control, a stereo camera ECU that calculates the relative speed and vehicle distance between the preceding vehicle and vehicle 1 based on images captured by a stereo camera, and an EFI-ECU that controls the engine fuel injection amount, intake air amount, etc.

The vehicle control system S is provided with a battery 3. The vehicle control system S is also provided with an ignition switch 4, which is a device for starting the engine of the vehicle 1 and controlling various electrical systems. A microcomputer (hereinafter, referred to as "microcomputer") 11 of the main ECU 10, which will be described later, is connected to the battery 3 via the ignition switch 4. When the ignition switch 4 is in an on state, the microcomputer 11 of the main ECU 10 is supplied with power from the battery 3, and when the ignition switch 4 is in an off state, power is not supplied from the battery 3. In addition to the microcomputer 11 of the main ECU 10, the vehicle control system S has other units that require power supply, and although not shown in FIG. 1, the battery 3 is configured to be able to supply power to the units that require power supply.

The vehicle control system S is equipped with an actuator 5, which is connected to the main ECU 10 and is driven and controlled by a CPU 12 (described later) provided in a microcomputer 11 (described later) of the main ECU 10.

The main ECU 10 is equipped with a microcomputer 11 and is provided with an on-board diagnostics (OBD) connector T for connecting a terminal equipped with a fault diagnosis tool for diagnosing faults in a vehicle such as the vehicle 1 (not shown; hereinafter, appropriately referred to as a "terminal equipped with a fault diagnosis tool").

The microcomputer 11 includes a CPU 12 that performs various calculations and various controls, memory 13 including a code flash memory (hereinafter referred to as "code flash") 13A, a data flash memory (hereinafter referred to as "data flash") 13B and an SRAM 13C, and an I/O port 14 which is a terminal or circuit that serves as a gateway for communication between the CPU 12 and peripheral devices within the computer. When the ignition switch 4 is on, power is supplied to the microcomputer 11 from the battery 3, and when the ignition switch 4 is off, power is not supplied from the battery 3.

The code flash 13A is a non-volatile memory that can rewrite the stored contents and can continue to hold the stored contents even when the power supply from the battery 3 is interrupted in addition to when the power supply from the battery 3 is being supplied. For example, it holds various programs such as the freeze frame data (FFD) storage process program in FIG. 2 and the freeze frame data (FFD) reading process program in FIG. 3. The data flash 13B is a non-volatile memory that can rewrite the stored contents and can continue to hold the stored contents even when the power supply from the battery 3 is interrupted in addition to when the power supply from the battery 3 is being supplied. For example, it holds various data such as FFD and keywords to be described later, and corresponds to the "non-volatile memory" of the present invention. The SRAM 13C is a volatile memory that can rewrite the stored contents and can continue to hold the stored contents while the power supply from the battery 3 is being supplied, but loses the stored contents when the power supply from the battery 3 is interrupted. For example, it holds various data such as FFD and keywords to be described later. The SRAM 13C has a faster read speed than the data flash 13B. Note that the code flash 13A may be replaced with, for example, a nonvolatile memory other than the code flash 13A, the data flash 13B may be replaced with, for example, a nonvolatile memory other than the data flash 13B, and the SRAM 13C may be replaced with, for example, a volatile memory other than the SRAM 13C that has a faster read speed than the data flash 13B or a nonvolatile memory other than the data flash 13B used instead.

In this embodiment, the CPU 12, for example, controls the drive of the actuator 5, and performs a freeze frame data (FFD) storage process, which will be described in detail later with reference to Figures 2 and 4, and a freeze frame data (FFD) reading process, which will be described in detail later with reference to Figures 3 and 4.

In the freeze frame data (FFD) retention process, when a fault occurs in the vehicle 1, the CPU 12 divides the FFD, which includes the collected vehicle information and fault cause information linked to the vehicle information, into multiple data (one data is, for example, composed of information with the same attribute: corresponding to the "section write data" of the present invention, and hereinafter referred to as "section write data" as appropriate), writes each of the multiple section write data as fault information to a corresponding section among multiple sections of the data flash 13B (one section is a memory area to write one section write data and one keyword), and performs a write process to write the same keyword (corresponding to the "correlated data with correlation" of the present invention) to each of the multiple sections as write confirmation information, and in the write process, after writing the section write data and keyword to one section, writes the section write data and keyword to another section (corresponding to the process by the "write means" of the present invention).

Here, the vehicle information is, for example, the measurement results of sensors connected to the main ECU 10 equipped with the CPU 12, and the measurement results of sensors connected to the other ECUs 30, 50, 70 acquired through CAN communication via the bus 2, such as coolant temperature information, engine RPM information, throttle opening information, vehicle speed information, fuel pressure information, and intake temperature information, and the CPU 12 periodically collects the vehicle information. Furthermore, the failure cause information is information related to the cause of the failure of the vehicle 1, such as communication anomaly information related to a communication anomaly in which regular communication with the ECU 30 has been interrupted, and the CPU 12 acquires the failure cause information when a failure occurs in the vehicle 1.

In the freeze frame data (FFD) read process, the CPU 12 reads the FFD from the data flash 13B, and at that time, judges whether or not the write confirmation information (keywords) held in each of the multiple sections of the data flash 13B are all the same. If it is judged that the write confirmation information (keywords) are all the same, the fault information (section write data) held in the multiple sections is information to be used for analyzing the fault of the vehicle 1, and if it is not judged that the write confirmation information (keywords) are all the same, the fault information is not information to be used for analyzing the fault of the vehicle 1 (corresponding to the process by the "judgment means" of the present invention). In addition, if it is not judged that the write confirmation information (keywords) are all the same, the CPU 12 initializes and erases the fault information (section write data) and the write confirmation information (keywords) held in each of the multiple sections of the data flash 13B (corresponding to the process by the "erasing means" of the present invention).

2. Freeze frame data (FFD) retention process 2.1. Processing flow of freeze frame data (FFD) retention process The processing flow of the freeze frame data (FFD) retention process performed by the CPU 12 of the main ECU 10 will be described in detail with reference to Fig. 2. The processing flow of the freeze frame data (FFD) retention process in Fig. 2 is executed at a predetermined cycle (e.g., 5 ms).

In the freeze frame data (FFD) retention process, the CPU 12 first determines whether a malfunction has occurred in the vehicle 1 (step S1).

If it is determined in the determination process of step S1 that no malfunction has occurred in the vehicle 1 (NO in step S1), the freeze frame data (FFD) retention process of FIG. 2 is terminated. On the other hand, if it is determined in the determination process of step S1 that a malfunction has occurred in the vehicle 1 (YES in step S1), the process proceeds to step S2 in order to write the FFD, which includes the collected vehicle information and malfunction cause information linked to the information, to the data flash 13B.

For example, the main ECU 10 periodically communicates with the other ECUs 30, 50, and 70, and the CPU 12 determines that a failure has occurred in the vehicle 1 due to a communication abnormality in which communication between the main ECU 10 and the ECUs 30 has been interrupted for a predetermined period of time (YES in step S1), and proceeds to processing in step S2 to write the FFD containing the collected vehicle information and failure cause information linked to the collected vehicle information to the data flash 13B. In this case, the vehicle information contained in the FFD includes the measurement results of the sensors connected to the main ECU 10 and the measurement results of the sensors connected to the ECUs 50 and 70, as well as the measurement results of the sensors connected to the ECU 30 that were received from the ECU 30 before communication with the ECU 30 was interrupted, and the failure cause information is communication abnormality information related to the communication abnormality with the ECU 30.

The CPU 12 generates a keyword (step S2) and proceeds to processing in step S3. In generating the keyword in step S2, the CPU 12 generates a keyword that is different from the previously generated keyword (so that it has no correlation with the previously generated keyword). A keyword that is different from the previously generated keyword is generated, for example, by randomly generating and extracting a random number, and using the extracted random number as the keyword.

The CPU 12 specifies the section of the data flash 13B into which the FFD and keywords are to be written first (step S3), and proceeds to step S4.

The CPU 12 writes the keyword generated in step S2 to the specified section of the data flash 13B as write confirmation information, and writes the relevant section write data that has not yet been written to the data flash 13B among the multiple section write data constituting the FFD to the specified section as failure information, performs a write process of the FFD and the keyword to the specified section (step S4), and proceeds to the process of step S5. Note that in the write process of step S4, for example, the keyword is written from the top area of the specified section, and the section write data is written from the area next to the area where the keyword was written.

The CPU 12 determines whether or not the entire FFD (all of the multiple section write data that make up the FFD) has been written to the data flash 13B (step S5).

If it is not determined in the determination process of step S5 that all of the FFD has been written to the data flash 13B (NO in step S5), proceed to the process of step S6.

The CPU 12 specifies the section of the data flash 13B into which the FFD and keywords will be written next (moves to the next specified section of the data flash 13B) (step S6), and returns to the processing of step S4.

If it is determined in the determination process of step S5 that all of the FFD has been written to the data flash 13B (YES in step S5), the freeze frame data (FFD) retention process of FIG. 2 is terminated.

2.2 Specific Example of Writing FFD to Data Flash A specific example of writing FFD to the data flash 13B in the freeze frame data (FFD) holding process of FIG. 2 will be described in detail with reference to FIG.

2.2.1. Example of Successful Writing to Data Flash of FFD A detailed description will be given of an example of successful writing to the data flash 13B of the FFD without interrupting the power supply during writing to the data flash 13B of the FFD when the Nth vehicle failure occurs, with reference to FIG. 4( a).

In the example of FIG. 4(a), the FFD when the Nth vehicle failure occurs is composed of four pieces of failure information A1 to A4, and the sections of data flash 13B to which the FFD is written are four sections A to D.

The CPU 12 determines whether a malfunction has occurred in the vehicle 1 (step S1), and if it determines that a malfunction has occurred in the vehicle 1 (YES in step S1), it proceeds to a process of writing the FFD, which includes the collected vehicle information and the malfunction cause information linked to the vehicle information, to the data flash 13B.

The CPU 12 generates a keyword (Key = 0x12345678) (step S2).

The CPU 12 designates the section of the data flash 13B into which the FFD and keyword are to be written first as section A (step S3), and writes Key=0x12345678 and failure information A1 to the designated section A (step S4), as shown in FIG. 4(a-1).

The CPU 12 determines whether the entire FFD has been written to the data flash 13B (step S5), and if it does not determine that the entire FFD has been written to the data flash 13B (NO in step S5), it designates section B as the section of the data flash 13B to which the FFD and keyword are to be written next (step S6), and writes Key=0x12345678 and failure information A2 to the designated section B (step S4), as shown in FIG. 4(a-2).

The CPU 12 determines whether the entire FFD has been written to the data flash 13B (step S5), and if it does not determine that the entire FFD has been written to the data flash 13B (NO in step S5), it designates section C as the section of the data flash 13B to which the FFD and keyword are to be written next (step S6), and writes Key=0x12345678 and failure information A3 to the designated section C (step S4), as shown in FIG. 4(a-3).

The CPU 12 determines whether the entire FFD has been written to the data flash 13B (step S5), and if it does not determine that the entire FFD has been written to the data flash 13B (NO in step S5), it designates section D as the section of the data flash 13B to which the FFD and keyword are to be written next (step S6), and writes Key=0x12345678 and failure information A4 to the designated section D (step S4), as shown in FIG. 4(a-4).

The CPU 12 determines whether or not the entire FFD has been written to the data flash 13B (step S5), and if it determines that the entire FFD has been written to the data flash 13B (YES in step S5), ends the freeze frame data (FFD) retention process of FIG. 2.

In a successful example of the above-mentioned FFD being written to the data flash 13B, as shown in FIG. 4(a), the four pieces of fault information A1 to A4 that make up the FFD when the Nth vehicle fault occurs are written and stored in the four sections A to D of the data flash 13B, and the same Key = 0x12345678 is written and stored in each of the sections A to D.

2.2.2. Example of Failure in Writing to the Data Flash of the FFD A failure example in which writing to the data flash 13B of the FFD fails because the power supply is cut off during writing to the data flash 13B of the FFD when the N+1th vehicle failure occurs will be described in detail with reference to FIG. 4(b).

In the example of FIG. 4(b), the FFD when the N+1th vehicle failure occurs is composed of four pieces of failure information B1 to B4, and the sections of the data flash 13B to which the FFD is written are four sections A to D. Furthermore, in the data flash 13B before the N+1th vehicle failure occurs, sections A to D hold the failure information A1 to A4 that constitute the FFD when the Nth vehicle failure occurs, and each of sections A to D holds the same Key = 0x12345678 (see FIG. 4(a)).

The CPU 12 determines whether a malfunction has occurred in the vehicle 1 (step S1), and if it determines that a malfunction has occurred in the vehicle 1 (YES in step S1), it proceeds to a process of writing the FFD, which includes the collected vehicle information and the malfunction cause information linked to the vehicle information, to the data flash 13B.

The CPU 12 generates a keyword (Key = 0x98765432) that is different (uncorrelated) from the previously created keyword (Key = 0x12345678) (step S2).

The CPU 12 designates the section of the data flash 13B into which the FFD and keyword are to be written first as section A (step S3), and writes Key=0x98765432 and failure information B1 to the designated section A (step S4), as shown in FIG. 4(b-1).

The CPU 12 determines whether the entire FFD has been written to the data flash 13B (step S5), and if it does not determine that the entire FFD has been written to the data flash 13B (NO in step S5), it designates section B as the section of the data flash 13B to which the FFD and keyword are to be written next (step S6), and writes Key=0x98765432 and failure information B2 to the designated section B (step S4), as shown in FIG. 4(b-2).

After writing Key = 0x98765432 and failure information B2 to specified section B, suppose that the power supply is cut off due to battery removal or a momentary interruption. In this case, the freeze frame data (FFD) storage process being executed ends without writing Key = 0x98765432 and failure information B3 to section C, and without writing Key = 0x98765432 and failure information B4 to section D. As a result, sections C and D will continue to hold the contents before the N+1th vehicle failure occurred, that is, Key = 0x12345678 and failure information A3 and Key = 0x12345678 and failure information A4 will continue to be held (Figures 4 (b-3) to (b-4)).

In the above-mentioned example of failure in writing the FFD to the data flash 13B, as shown in FIG. 4B, the FFD failure information B1 and B2 when the N+1th vehicle 1 failure occurs is written and stored in sections A and B of the data flash 13B, and Key=0x98765432 is written and stored in each of sections A and B. Also, FFD failure information A3 and A4 when the Nth vehicle failure occurs is stored in sections C and D of the data flash 13B, and Key=0x12345678 is stored in each of sections C and D. In this way, Key=0x98765432 stored in each of sections A and B and Key=0x12345678 stored in each of sections C and D are different keywords.

3. Freeze frame data (FFD) reading process 3.1. Processing flow of freeze frame data (FFD) reading process The processing flow of the freeze frame data (FFD) reading process performed by the CPU 12 of the main ECU 10 will be described in detail with reference to Fig. 3. The processing flow of the freeze frame data (FFD) reading process in Fig. 3 is executed when the CPU 12 is started up or restarted.

In the freeze frame data (FFD) read process, the CPU 12 first determines whether or not an FFD is stored in the data flash 13B (step S51). If it is determined that an FFD is not stored in the data flash 13B (NO in step S51), the freeze frame data (FFD) read process of FIG. 3 is terminated. On the other hand, if it is determined that an FFD is stored in the data flash 13B (YES in step S51), the process proceeds to step S52.

The CPU 12 reads the write confirmation information (keywords) and failure information (section write data stored in the relevant section among the multiple section write data constituting the FFD) from each of the multiple sections of the data flash 13B, writes and stores them in the SRAM 13C (step S52), and proceeds to the processing of step S53.

The CPU 12 determines whether the write confirmation information (keywords) read from each of the multiple sections of the data flash 13B and written to the SRAM 13C in step S52 are all the same (step S53). If it is determined in the determination process of step S53 that the write confirmation information (keywords) are all the same (YES in step S53), the freeze frame data (FFD) read process of FIG. 3 is terminated. On the other hand, if it is not determined in the determination process of step S53 that the write confirmation information (keywords) are all the same (NO in step S53), the process proceeds to step S54.

The CPU 12 initializes and erases the FFD and keywords from the data flash 13B, initializes and erases the FFD and keywords from the SRAM 13C (step S54), and ends the freeze frame data (FFD) reading process of FIG. 3. To further describe the process of step S54, it initializes and erases the failure information (section write data) and write confirmation information (keywords) from each of the multiple sections of the data flash 13B, and initializes and erases from the SRAM 13C the failure information (section write data) and write confirmation information (keywords) that were read from each of the multiple sections of the data flash 13B and written to the SRAM 13C.

After the freeze frame data (FFD) reading process in FIG. 3 is completed, the fault diagnosis tool-equipped terminal is connected to the OBD connector T, and the fault diagnosis tool-equipped terminal requests the CPU 12 of the main ECU 10 to send the FFD.

When the write confirmation information (keywords) of multiple sections is the same when the CPU 12 is started or restarted, the CPU 12 responds to a transmission request from the fault diagnosis tool-equipped terminal by reading from SRAM 13C the fault information (section write data) that has been read from each of the multiple sections of the data flash 13B and written to SRAM 13C, and transmitting it to the fault diagnosis tool-equipped terminal. This allows the fault diagnosis tool-equipped terminal to analyze the vehicle fault using only the multiple section write data (fault information) that make up one freeze frame data.

On the other hand, if the write confirmation information (keywords) of the multiple sections at the time of startup or restart of CPU 12 is different from the other write confirmation information (keywords), the fault information (section write data) read from each of the multiple sections of data flash 13B and written to SRAM 13C is erased from SRAM 13C, so that the fault information (section write data) held in each of the multiple sections of data flash 13B at the time of startup or restart of CPU 12 is not transmitted to the fault diagnosis tool-equipped terminal. This prevents the fault diagnosis tool-equipped terminal from analyzing vehicle faults including those not related to one freeze frame data.

3.2 Example of Reading FFD from Data Flash An example of reading the freeze frame data (FFD) from the data flash 13B in the FFD reading process of FIG. 3 will be described in detail with reference to FIG.

3.2.1 Example of Reading FFD When Writing of FFD to Data Flash is Successful An example of reading the FFD when writing of the FFD to the data flash 13B is successful will be described in detail with reference to FIG.

The CPU 12 determines whether an FFD is stored in the data flash 13B (step S51), and determines that an FFD is stored (YES in step S51).

The CPU 12 reads "Key = 0x12345678 and failure information A1", "Key = 0x12345678 and failure information A2", "Key = 0x12345678 and failure information A3", and "Key = 0x12345678 and failure information A4" from sections A, B, C, and D of the data flash 13B, and writes them to the SRAM 13C (step S52).

The CPU 12 determines whether Key=0x12345678, Key=0x12345678, Key=0x12345678, Key=0x12345678 read from sections A, B, C, and D of the data flash 13B and written to the SRAM 13C are all identical (step S53), and determines that they are all identical (YES in step S53), thereby terminating the freeze frame data (FFD) reading process of FIG. 3.

After the freeze frame data (FFD) reading process in FIG. 3 is completed, the fault diagnosis tool-equipped terminal is connected to the OBD connector T, and the fault diagnosis tool-equipped terminal requests the CPU 12 of the main ECU 10 to transmit the FFD. In response to the transmission request from the fault diagnosis tool-equipped terminal, the CPU 12 reads the fault information A1 to A4 from the SRAM 13C and transmits it to the fault diagnosis tool-equipped terminal. This allows the fault diagnosis tool-equipped terminal to analyze the vehicle fault using only the four fault information A1 to A4 that make up the freeze frame data when the Nth vehicle fault occurs.

3.2.2. Example of Reading FFD When Writing of FFD to Data Flash Fails An example of reading the FFD when writing of the FFD to the data flash 13B fails will be described in detail with reference to FIG.

The CPU 12 determines whether an FFD is stored in the data flash 13B (step S51), and determines that an FFD is stored (YES in step S51).

The CPU 12 reads "Key = 0x98765432 and failure information B1", "Key = 0x98765432 and failure information B2", "Key = 0x12345678 and failure information A3", and "Key = 0x12345678 and failure information A4" from sections A, B, C, and D of the data flash 13B, and writes them to the SRAM 13C (step S52).

The CPU 12 determines whether Key = 0x98765432, Key = 0x98765432, Key = 0x12345678, and Key = 0x12345678 read from sections A, B, C, and D of the data flash 13B and written to the SRAM 13C are all identical (step S53), and determines that they are not all identical (NO in step S53). The CPU 12 erases "Key = 0x98765432 and failure information B1", "Key = 0x98765432 and failure information B2", "Key = 0x12345678 and failure information A3", and "Key = 0x12345678 and failure information A4" from sections A, B, C, and D of the data flash 13B, and erases "Key = 0x98765432 and failure information B1", "Key = 0x98765432 and failure information B2", "Key = 0x12345678 and failure information A3", and "Key = 0x12345678 and failure information A4" from the SRAM 13C (step S54), and ends the freeze frame data (FFD) reading process of FIG. 3.

After the freeze frame data (FFD) reading process in FIG. 3 is completed, the fault diagnosis tool-equipped terminal is connected to the OBD connector T, and even if the fault diagnosis tool-equipped terminal requests the CPU 12 of the main ECU 10 to send an FFD, the fault information B1, B2, A3, and A4 stored in sections A to D of the data flash 13B when the CPU 12 is started or restarted will not be sent from the CPU 12 to the fault diagnosis tool-equipped terminal. This prevents the fault diagnosis tool-equipped terminal from analyzing a vehicle fault by mixing the fault information B1 and B2 related to the freeze frame data when the N+1th vehicle fault occurs and the fault information A3 and A4 related to the freeze frame data when the Nth vehicle fault occurs.

＜Effects＞
According to the above embodiment, when a fault occurs in a vehicle, if writing of a certain FFD to the data flash 13B is successful, all of the write confirmation information (keywords) held in each of the multiple sections of the data flash 13B are the same (see FIG. 4A). On the other hand, if writing of a certain FFD to the data flash 13B fails due to a power supply interruption during writing of the certain FFD to the data flash 13B, the write confirmation information (keywords) held in the section to which the section write data could be written differs from the write confirmation information (keywords) held in the section to which the section write data could not be written (see FIG. 4B). For this reason, if there is any write confirmation information (keyword) held in each of the multiple sections that is different from other write confirmation information (keywords), it can be determined that the fault information (section write data) held in each of the multiple sections includes information unrelated to the certain FFD, and it is possible to prevent a problem in which a vehicle fault is analyzed including information unrelated to the certain FFD.

In addition, by determining whether all of the write confirmation information (keywords) held in each of the multiple sections of data flash 13B are the same, without determining whether all of the failure information (section write data) held in each of the multiple sections of data flash 13B is related to one FFD, it is possible to determine whether all of the failure information (section write data) held in each of the multiple sections is related to one FFD, thereby shortening the time required for this determination.

In addition, by using write confirmation information (keywords) with a small data size, it is possible to reduce the possibility of the power supply being cut off while writing to the data flash 13B of one FFD.

In addition, by making the keyword generated when the current vehicle failure occurs different from the keyword generated when the previous vehicle failure occurred, it is possible to prevent the vehicle failure from being analyzed using data that contains a mixture of the FFD when the current vehicle failure occurred and the FFD when the previous vehicle failure occurred. In this way, it is suitable for storing a single freeze frame data in multiple sections of non-volatile memory.

In addition, if there is a difference in the write confirmation information (keywords) stored in each of the multiple sections, the FFD and keyword are erased from each of the data flash 13B and the SRAM 13C, which further prevents the problem of using failure information to analyze a vehicle failure when writing the FFD to the data flash 13B fails in the future.

In addition, when the CPU 12 transmits an FFD in response to a request to transmit an FFD from a terminal equipped with a fault diagnosis tool connected to the OBD connector T, the CPU 12 reads and transmits the multiple section write data (fault information) that constitute the FFD from the SRAM 13C, rather than reading and transmitting the multiple section write data (fault information) that constitute the FFD from the data flash 13B, so that the multiple section write data (fault information) that constitutes the FFD can be transmitted quickly to the terminal equipped with a fault diagnosis tool.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms.

For example, in the above embodiment, the same keyword is used as an example of correlated correlation data, and different keywords are used as an example of uncorrelated correlation data, but this is not limited to this. For example, the correlated correlation data may be other than the same keyword as long as it enables determination that each of the failure information (section write data) of multiple sections is related to the same freeze frame data, and uncorrelated data other than different keywords may be used as long as it enables determination that each of the failure information (section write data) of multiple sections is related to different freeze frame data.

In the above case, for example, the case where the FFD is divided into four and written to the four sections A to D of the data flash 13B will be described. When the previous vehicle 1 malfunction occurred, correlation data DA1, DA2, DA3, DA4 were written to sections A, B, C, and D as write confirmation information, and before the current vehicle 1 malfunction occurred, correlation data DA1, DA2, DA3, DA4 were held in sections A, B, C, and D. These correlation data DA1, DA2, DA3, DA4 are correlated with each other. In the freeze frame data (FFD) reading process of FIG. 2 when the current vehicle 1 malfunction occurs, step S2 is replaced by a process of generating correlation data DB1, DB2, DB3, DB4 that are not correlated with the correlation data DA1, DA2, DA3, DA4. These correlation data DB1, DB2, DB3, DB4 are correlated with each other. Then, step S4 replaces the part where the keyword is written to the specified section with the part that writes the correlation data DB1 to DB4 that has not yet been written to the specified section. In the freeze frame data (FFD) read process of FIG. 3, the write confirmation information (keyword) is replaced with the write confirmation information (correlation data DB1 to DB4) in the processes of steps S52 to S54, and in step S53, it is determined whether the write confirmation information read from each of the multiple sections A to D and written to SRAM 13C is correlated with each other. If it is determined that the write confirmation information is correlated with each other, the freeze frame data (FFD) read process is terminated, and if it is not determined that the write confirmation information is correlated with each other, the process proceeds to step S54.

In addition, the contents described in the above embodiment and the contents described in the above modified example may be combined as appropriate.

In addition, various design modifications can be made to the above-mentioned configuration within the scope of the claims.

The present invention can be widely applied to vehicle control devices that perform control related to the storage of freeze frame data.

1: Vehicle S: Vehicle control system 10: Main ECU
11: Microcomputer 12: CPU
13B: Data flash 13C: SRAM

Claims (3)

A vehicle control device that controls storage of freeze frame data when a vehicle failure occurs,
a write process for writing each of a plurality of section write data constituting one freeze frame data as failure information to a corresponding section of a plurality of sections of a non-volatile memory when a failure occurs in one vehicle, and for writing correlation data having correlation with each of the plurality of sections as write confirmation information, the write process including a write means for writing the section write data and the correlation data to one section and then writing the section write data and the correlation data to another section;
and a determination means for determining whether or not the write confirmation information stored in each of the plurality of sections is correlated with each other when reading out the one freeze frame data from the non-volatile memory, and determining that the fault information stored in the plurality of sections is information to be used for analyzing a vehicle fault if it is determined that the write confirmation information is correlated with each other, and not determining that the fault information is information to be used for analyzing a vehicle fault if it is not determined that the write confirmation information is correlated with each other. The vehicle control device according to claim 1, characterized in that the writing means writes the correlated correlation data currently written to each of the plurality of sections as the write confirmation information when a current vehicle failure occurs, to data that is not correlated with the correlated correlation data previously written to each of the plurality of sections as the write confirmation information when a previous vehicle failure occurred. 3. The vehicle control device according to claim 1, further comprising an erasure means for erasing the failure information and the write confirmation information stored in each of the multiple sections when it is determined that the write confirmation information is not correlated with each other.

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