JP2013073609A - Information processor and data recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information vehicle data recording device for improving use efficiency of a flash memory.SOLUTION: An information processor 100 for storing vehicle data in a non-volatile ring buffer when a vehicle state fixed in advance is detected includes: vehicle data collection means 32 for collecting vehicle data before and after the vehicle state is detected; vehicle data primary storage means 21 for primarily storing the vehicle data; data deletion means 34 for deleting the vehicle data in the ring buffer for each deletion unit block in the order of older vehicle data; and data writing means 35 for writing the vehicle data stored in the vehicle data primary storage means subsequently to the last vehicle data in the ring buffer. The data deletion means holds the vehicle data in the deletion unit block where the oldest vehicle data is stored until the vehicle state is detected even if a free space which has the size of the vehicle data or more is used up.

Description

  The present invention relates to an information processing apparatus that stores vehicle data in a non-volatile ring buffer when a predetermined vehicle situation is detected.

  The running vehicle data is often useful for manufacturers and the like to identify the cause of the failure and analyze the situation at the time of the occurrence of the malfunction. For this reason, a vehicle data recording device that records vehicle data may be mounted on the vehicle. The vehicle data includes detection values of various sensors mounted on the vehicle. Since vehicle data is recorded when an event occurs, it can occur irregularly as long as the vehicle is traveling.

  As a recording medium of the vehicle data recording device, a non-volatile memory is used so as to hold the recording even after IG-OFF. Non-volatile memory includes flash memory, HDD, EEPROM, and the like, but flash memory is often adopted in terms of size, stability, cost, and writing speed. However, the flash memory has a restriction that data can be erased only in units of blocks (erase blocks) (writing is possible in units of bytes or words). Further, when the vehicle data recording device simply repeats data rewriting, the number of times of rewriting data of a specific block increases. However, the flash memory has an upper limit on the number of times it can be rewritten, so that the block reaches the end of its life earlier, and the product life of the entire flash memory is shortened.

  For this reason, a technique for avoiding concentration of rewriting to a certain block or averaging the number of rewriting of a block is known (see, for example, Patent Document 1). In Patent Document 1, a logical ring buffer in which blocks are arranged in order is configured, and data is recorded sequentially from the first erased sector in a memory block having erased sectors when data is recorded in a flash memory. A recording method is disclosed. In this data recording method, after the data is recorded in the last sector of the memory block, the data of the next memory block on the ring buffer is erased, and at the next recording, the data is sequentially recorded from the first sector of the memory block. Continue recording.

JP 2004-071033 A

  However, the data recording method described in Patent Document 1 has a problem that no data is written in the block until the vehicle data is written at the next event after the block is erased.

FIG. 1 is an example of a diagram for explaining a problem of a conventional data recording method. The squares 1 to N represent blocks of erase units, and the blocks are logically connected to form a ring buffer.
(i) The vehicle data recording device collects vehicle data before and after an event occurs.
(ii) The vehicle data recording device writes the vehicle data to the flash memory (Nth block in the figure).
(iii) When the vehicle data is written at the end of the block, the vehicle data recording device erases the next block (the first block in the figure).
(iv) When the next event occurs, the vehicle data recording device collects vehicle data before and after the event.
(v) The vehicle data recording device writes the vehicle data at the head of the already erased block (the first block in the figure).

  As described above, during the period from (iii) to (v), a time during which vehicle data is not recorded occurs in the flash memory block, and the use efficiency of the memory is reduced.

  In view of the above problems, an object of the present invention is to provide an information vehicle data recording apparatus that improves the use efficiency of a flash memory.

  The present invention provides an information processing apparatus for storing vehicle data in a non-volatile ring buffer when a predetermined vehicle situation is detected, and vehicle data collection means for collecting vehicle data before and after the vehicle situation is detected. The vehicle data primary storage means for primary storage of the vehicle data collected by the vehicle data collection means, and when there is no free space larger than the size of the vehicle data, the vehicle data in the ring buffer is erased in chronological order for each erase unit block. Data erasing means; and data writing means for writing the vehicle data stored in the vehicle data primary storage means in succession to the last vehicle data in the ring buffer, wherein the data erasing means Even if there is no more free space than the size, the oldest vehicle data is stored until the vehicle status is detected. It holds vehicle data erase unit block, wherein the vehicle condition is deleted vehicle data erase unit block oldest vehicle data in response to having been detected are stored, characterized in that.

  It is possible to provide an information vehicle data recording device that improves the use efficiency of the flash memory.

It is an example of the figure explaining the problem of the conventional data recording method. It is an example of the figure which illustrates typically recording of the vehicle data by the vehicle data recording device of this embodiment. It is an example of the block diagram of a vehicle data recording device. It is an example of the functional block diagram of a vehicle data recording device. It is an example of the flowchart figure which shows the operation | movement procedure of a vehicle data recording device. It is an example of the figure which illustrates typically the relationship between a block size and the size of vehicle data. It is an example of the figure which illustrates typically the non-volatile memory in which vehicle data is stored straddling between blocks. (Example 2) which is an example of the figure which illustrates typically the recording of the vehicle data by a vehicle data recording device. (Example 2) which is an example of the functional block diagram of a vehicle data recording device. It is an example of the flowchart figure which shows the operation | movement procedure of a vehicle data recording device. It is an example of the figure which illustrates typically the relationship between the free capacity of a save area, and the size of vehicle data.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 2 is an example of a diagram schematically illustrating the recording of vehicle data by the vehicle data recording apparatus of the present embodiment.
(i) The vehicle data recording device collects vehicle data before and after an event occurs.
(ii) The vehicle data recording device writes the vehicle data to the flash memory (Nth block in the figure).
(iii) Even if the vehicle data recording device writes the vehicle data in the block, it does not erase the next block.
(iv) The vehicle data recording device collects vehicle data before and after the next event occurs.
(v) If there is no free space in the block, the vehicle data recording device erases the next block in the ring buffer (the first block in the figure).
(vi) The vehicle data recording device writes the vehicle data at the head of the erased block.

  The vehicle data recording device does not erase the next block in (iii), but erases the block when the next event occurs, so there is almost no time when no vehicle data is recorded in the block, and the flash memory is used. Efficiency can be improved.

[Configuration example]
FIG. 3 shows an example of a configuration diagram of the vehicle data recording apparatus 100 of the present embodiment. The vehicle data recording device 100 is configured by one or more ECUs (Electronic Control Units), and each ECU is connected via an in-vehicle network 13. The protocol of the in-vehicle network 13 includes CAN (Controller Area Network), FlexRay, Lin (Local Interconnect Network), and the like. In this embodiment, the CAN will be described as an example.

  The transmission control ECU 12 is an ECU that transmits CAN data (vehicle data) to the reception control ECU 11. Although there is only one transmission control ECU 12 in the figure, there may be two or more ECUs that generate vehicle data. Since the hardware configuration of the transmission control ECU 12 is the same as that of the reception control ECU 11, the illustration is omitted. The reception control ECU 11 and the transmission control ECU 12 are functional names, and the ECU that controls the in-vehicle device can also serve as the reception control ECU 11 and the transmission control ECU 12. Examples of the reception control ECU 11 include a meter ECU, a body ECU, a navigation ECU, a communication control ECU, and the like. Examples of the transmission control ECU 12 include an engine ECU, a brake ECU, a power steering ECU, an airbag ECU, a transmission ECU, and the like. The reception control ECU itself may generate vehicle data.

  Meter ECU is the operation state of switches (eg, turn signal switch, hand brake switch, etc.), signals acquired from other ECUs (vehicle speed, engine speed, door lock state, seat belt wearing state, wiper operating state, etc.) Is converted into a numerical value or the pointer position of the swinging needle and displayed. The body ECU detects on / off of the courtesy switch, controls the interior lamp, and performs door locking / unlocking based on the operation of the occupant. The navigation ECU detects position information of the vehicle using GNSS (Global Navigation Satellite Systems) or the like, and displays a surrounding road map and a vehicle position icon on a display device such as a liquid crystal display. In addition, the route to the destination is calculated and route guidance such as turning left and right or changing lanes is performed. The navigation ECU may be equipped with a radio or television reception function and an audiovisual function such as a CD, DVD, or BD player. The communication control ECU is connected to a wireless communication network such as a mobile phone network, a wireless LAN, and WIMAX, and communicates with various servers. Some or all of the vehicle data stored in the nonvolatile memory may be transmitted to an external server.

  The engine ECU detects the accelerator opening and the like, determines the throttle opening and the fuel injection amount, and controls the ignition timing based on the crank angle. The brake ECU detects slip from the rotational speed of each wheel, and reduces the braking force of the wheel that is slipping to prevent wheel lock (ABS), and performs idling of the wheel at the time of transmission. When detected, TRC (Traction Control) control for applying a braking force to the wheel is performed. In addition, ESC (Electronic Stability Control) control is performed to adjust the braking force of each wheel based on the yaw rate, steering angle, wheel speed, and the like. The power steering ECU detects the steering torque of the driver, and performs steering support for driving the motor and rotating the steering shaft in the steering direction of the driver. Further, while the LKA (Lane Keeping Assist system) is operating, the steering shaft is rotationally driven so as to travel substantially in the center of the travel lane recognized by the camera ECU. The airbag ECU deploys airbags (driver seat, passenger seat, side airbag, curtain airbag, etc.) by analyzing acceleration / deceleration and lateral deceleration acting on the vehicle. The transmission ECU switches the gear by opening and closing a valve through which the transmission fluid passes according to the accelerator opening and the increase / decrease in engine speed due to a brake operation, acceleration, vehicle speed, and the like.

  The reception control ECU 11 includes an OS / CAN driver 25, a microcomputer 24, a RAM 21, a ROM 22, and a nonvolatile memory 23. The OS abstracts general-purpose functions of the microcomputer 24 so that a program executed by the CPU can use the functions of the microcomputer 24. In addition, the OS manages tasks in a multitask environment, protects data for each task, and performs communication between tasks.

  The CAN driver requests a CAN controller (not shown) to transmit CAN data, or extracts a data portion from the CAN data received by the CAN controller. That is, the CAN driver stores data requested by the program in the CAN protocol format and sets it in the buffer of the CAN controller. When the CAN controller receives CAN data with a predetermined CAN ID, the CAN driver sends data extracted from the CAN data to the program according to the CAN protocol format.

  The microcomputer 24 mainly includes a CPU, a RAM (not shown), a ROM, a DMAC (Direct Memory Access), and an INTC (Interrupt Controller). In the figure, the reception control ECU 11 has a RAM 21, a ROM 22, and a nonvolatile memory 23 in addition to the microcomputer 24, but these can be stored in the microcomputer 24 and configured as one microcomputer 24. The RAM 21 is a volatile storage means used by the program (onboard application), and the ROM 22 is a non-volatile memory 23 that stores the onboard program. The nonvolatile memory 23 is a flash memory according to this embodiment that stores vehicle data. The non-volatile memory 23 is given a logical order for each block which is an erasing unit, and constitutes a ring buffer.

  FIG. 4 is an example of a functional block diagram of the vehicle data recording device 100. Each function of FIG. 4 is realized by the CPU 24 of the microcomputer 24 executing a program stored in the ROM 22 and cooperating with ICs such as the nonvolatile memory 23 and the DMAC and CAN controllers.

  The reception control ECU 11 includes an event detection unit 31, a vehicle data collection unit 32, a free space determination unit 33, a block deletion unit 34, and a vehicle data writing unit 35. The event detection unit 31 detects the occurrence of an event that triggers the storage of vehicle data. Events include, for example, IG-ON, IG-OFF, vehicle speed has started, stopped, vehicle speed has exceeded a predetermined value during driving, acceleration / deceleration / lateral acceleration has exceeded a predetermined value When the yaw rate exceeds a predetermined value, the ABS / ESC has worked, the airbag has been deployed, and the like. The event detection unit 31 detects an event based on a detection signal detected by the sensor and CAN data transmitted by the transmission control ECU 12. In addition, the event occurrence notification itself may be acquired from the transmission control ECU 12. When detecting an event, the event detection unit 31 requests the vehicle data collection unit 32 to collect vehicle data.

  The vehicle data collection unit 32 collects vehicle data from the transmission control ECU 12. The stored vehicle data includes vehicle speed, acceleration (deceleration), accelerator opening, amount of brake pedal depression, engine speed, yaw rate, position information, and the like. Furthermore, you may record the image of the vehicle front, side, back, etc. which the camera image | photographed.

  The content of the vehicle data is fixed regardless of the type of event. However, the contents of the vehicle data may be changed depending on the type of event, and it is not difficult to change the size of the vehicle data. However, if the data size changes for each event, it is difficult to determine at which address the event has been switched in the later analysis. Therefore, even if the content of the vehicle data changes depending on the type of event, the size of the vehicle data is preferably the same.

  Moreover, when changing the size of vehicle data according to the kind of event, it is suitable to add event ID to vehicle data. Since the size of one vehicle data is determined by the event ID, it is possible to determine at which address the vehicle data in the nonvolatile memory 23 is switched to the next vehicle data.

  Further, the vehicle data collection unit 32 collects vehicle data before the event occurrence and vehicle data after the event occurrence, respectively. Vehicle data before the occurrence of an event includes vehicle speed, acceleration (deceleration), accelerator opening, and brake pedal depression amount. Examples of vehicle data after the occurrence of an event include engine speed, yaw rate, and position information. It does not preclude collecting the same data before and after the event occurs. The vehicle data collection unit 32 stores the vehicle data before the occurrence of the event in the RAM 21 periodically, for example, before the occurrence of the event is detected. When the occurrence of an event is detected, the vehicle data after the occurrence of the event is stored in the RAM 21. The vehicle data writing unit 35 writes the vehicle data before the occurrence of the event and the vehicle data after the occurrence of the event stored in the RAM 21 in the nonvolatile memory 23.

  The free space determination unit 33 determines whether there is a free space in the block of the nonvolatile memory 23. The size of the vehicle data at one time, the address at which the vehicle data was written last, and the block size are known. Therefore, the free space determination unit 33 determines whether there is a free space in the block of the nonvolatile memory 23 based on whether there is a free space of the size of the vehicle data for one time in the block. If there is no free space of the size of the vehicle data for one time, the block erasure unit 34 is requested to erase one block. When there is an empty area of the size of the vehicle data for one time, the vehicle data writing unit 35 is requested to write the vehicle data to the nonvolatile memory 23.

  The block erasure unit 34 erases the block next to the block in which the vehicle data was last written when there is no empty area of the size of the vehicle data for one time in the block. Thereby, an empty area is secured. As described above, the flash memory can be erased only in units of blocks.

  The vehicle data writing unit 35 writes the vehicle data stored in the RAM 21 into the nonvolatile memory 23. Specifically, the vehicle data is written from the address next to the address where the vehicle data was written last. The last address of the vehicle data stored in the nonvolatile memory 23 is held in the RAM 21 or the like for the next writing as a pointer.

[Operation procedure]
FIG. 5 is an example of a flowchart showing an operation procedure of the vehicle data recording apparatus 100 of the present embodiment. The procedure of FIG. 5 is repeatedly executed after, for example, IG-ON (after a system startup in the case of a hybrid vehicle or an electric vehicle).

  The vehicle data collection unit 32 collects vehicle data before the event (S10).

  The vehicle data collection unit 32 determines whether the event detection unit 31 has detected the occurrence of an event while collecting vehicle data before the event (S20). When the event detection unit 31 does not detect the occurrence of an event (No in S20), the vehicle data collection unit 32 continues to collect vehicle data before the event.

  When the event detection unit 31 detects the occurrence of an event (Yes in S20), the vehicle data collection unit 32 collects vehicle data after the event (S30). Thereby, the vehicle data which should be memorize | stored at the time of event occurrence was able to be collected.

  The free space determination unit 33 determines whether there is a free space necessary for storing the vehicle data in the nonvolatile memory 23 (S40). The free space determination unit 33 determines whether or not a value obtained by adding the size of the vehicle data to the start address of the vehicle data write destination specified by the pointer is larger than the last address of one block. Since the size of one block is fixed, the last address of one block is known.

  When there is an empty area in the block (Yes in S40), the vehicle data writing unit 35 writes the vehicle data in the empty area (S50).

  On the other hand, when there is no free area in the block (No in S40), the block erasing unit 34 erases the block in units of blocks (S60).

  The vehicle data writing unit 35 writes the vehicle data in the empty area generated by erasure (S50).

  Next, the vehicle data writing unit 35 updates the pointer according to the size of the written vehicle data (S70). Thus, the pointer indicates the start address of the next vehicle data write destination in the nonvolatile memory 23.

  As described above, by erasing one block immediately before writing the vehicle data after the occurrence of the event, the time during which the block is erased can be shortened, and the use efficiency of the nonvolatile memory 23 can be improved.

[Modification]
As described above, the use efficiency of the nonvolatile memory 23 can be improved by erasing one block after the occurrence of an event. However, if the size of the vehicle data is small compared to the size of one block (hereinafter referred to as the block size), the time during which no data is stored in the block becomes longer and the effect of improving the use efficiency is reduced.

  FIG. 6 is an example of a diagram for schematically explaining the relationship between the block size and the size of the vehicle data. In FIG. 6A, since the size of the vehicle data is smaller than the block size, an area where no data is stored becomes large. When an event occurs, the area in which no data is stored is sequentially reduced, but the area in which no data is stored reduces the memory use efficiency.

  On the other hand, in FIG. 6B, the size of the vehicle data is about half of the block size. In this case, immediately after the block is erased and one vehicle data is written, the area in which no data is stored can be suppressed to half or less of the block size. Therefore, the larger the vehicle data size is relative to the block size, the easier it is to improve the memory usage efficiency.

  In FIG. 6C, the vehicle data size and the block size are the same. In this case, an area in which no data is stored can be made zero immediately after the block is erased and one vehicle data is written.

  Further, in FIG. 6D, the size of the vehicle data is an integral multiple of the block size. In this case, an area in which no data is stored can be made zero immediately after two blocks are erased and one vehicle data is written. Therefore, as shown in FIGS. 6C and 6D, when the size of the vehicle data is an integer multiple of the block size, the memory use efficiency can be improved most.

In this embodiment, a case where vehicle data is stored across blocks will be described.
FIG. 7 is an example of a diagram schematically illustrating the nonvolatile memory 23 in which vehicle data is stored across blocks. The hatched square in the figure is one vehicle data, and straddles the first block and the second block. If the block size is not an integer multiple of the vehicle data size, one vehicle data may be recorded across the blocks. Even if the size of the block is an integral multiple of the size of the vehicle data, if data other than the vehicle data is stored, one vehicle data may be recorded across the blocks.

  When an event occurs and vehicle data is written to the first block, the block erasure unit 34 erases the first block, so only a part of the vehicle data straddling the first block and the second block is present. Erased. For this reason, the continuity is lost in the vehicle data straddling the first block and the second block, and the usefulness as vehicle data is reduced (cannot be used for analysis). If the vehicle data whose continuity is lost cannot be used for analysis, the use efficiency of the nonvolatile memory 23 is reduced as in the case where the vehicle data is substantially deleted.

  Therefore, in this embodiment, a non-volatile memory 23 is provided with a save area, and when one block of vehicle data is stored in the save area, the block of the non-volatile memory 23 is erased and one block of vehicles in the save area is stored. The vehicle data recording device 100 that writes data will be described.

FIG. 8 is an example of a diagram schematically illustrating the recording of vehicle data by the vehicle data recording apparatus 100 of the present embodiment. In FIG. 8, a save area for one block is provided. The save area is provided in the nonvolatile memory 23. A save area may be provided in the RAM 21.
(i) Since an event has occurred, the vehicle data recording device 100 collects vehicle data before and after the event occurs.
(ii) There is already no free space in the nonvolatile memory 23. For this reason, the vehicle data recording device 100 writes the vehicle data in the retreat area.
(iii) Subsequently, since an event has occurred, the vehicle data recording device 100 collects vehicle data before and after the event occurrence.
(iv) When the vehicle data recording device 100 writes the vehicle data in the evacuation area, the vehicle data recording device 100 determines whether or not the data is one block or more, and when the vehicle data of one block or more is evacuated, erases the first block. .
(v) Since one block of free space has been generated, the vehicle data in the evacuation area and the latest vehicle data are written. The vehicle data in the evacuation area is no longer needed and is deleted.

  According to such a procedure, compared with the case where the vehicle data for one block was deleted at the time of (ii) in the past, the first block until the vehicle data for one block was deleted at (iv). And the time when the continuity of the vehicle data straddling the second block is lost can be shortened.

  FIG. 9 shows an example of a functional block diagram of the vehicle data recording apparatus 100 of the present embodiment. 9, the same parts as those in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted.

  The free space determination unit 33 according to the present embodiment determines whether there is a free space in the block until writing to each block of the nonvolatile memory 23 is completed. However, in this embodiment, when the writing to the last N block is completed, there is always no free area in the block. Therefore, after the writing to each block is completed, the free area determination unit 33 determines whether there is a free area. There is no need to judge. However, there is no inconvenience even if the free area determination unit 33 determines whether or not there is a free area in the block even after the writing to each block is completed.

  Similarly, the vehicle data writing unit 35 writes the vehicle data to the block until the writing to each block is completed, but then does not write the vehicle data directly to the block.

  After the writing to each block is completed, there is no free area in the nonvolatile memory 23. Therefore, in this embodiment, the save area writing unit 36 writes the vehicle data in the save area. Once the data is written in the save area, a part of the vehicle data straddling the two blocks is erased, and the time when the continuity of the vehicle data is lost can be shortened.

  The save area operation unit 37 determines whether or not one block or more of vehicle data is stored in the save area before actually storing it. When vehicle data for one block or more is stored, the block erasure unit 34 is requested to erase the block. When the block erasure unit 34 erases one block, the evacuation area operation unit 37 writes the vehicle data in the evacuation area and the latest vehicle data into the block of the nonvolatile memory 23.

  FIG. 10 is an example of a flowchart showing an operation procedure of the vehicle data recording apparatus 100 of the present embodiment. The procedure up to S30 in FIG. 10 is the same as that in FIG. That is, when the event detection unit 31 detects the occurrence of an event, the vehicle data collection unit 32 collects vehicle data after the event (S30). Thereby, the vehicle data which should be memorize | stored at the time of event occurrence was able to be collected.

  Next, the free space determination unit 33 determines whether or not there is a free space necessary for storing the vehicle data in the nonvolatile memory 23 (S40). The free space determination unit 33 determines whether or not a value obtained by adding the size of the vehicle data to the start address of the vehicle data write destination specified by the pointer is larger than the last address of one block. Since one block is not erased in this embodiment, the determination in S40 becomes No after one round of storage in the nonvolatile memory 23. When there is an empty area in the block (Yes in S40), the vehicle data writing unit 35 writes the vehicle data in the empty area (S50).

  When there is no free area in the block (No in S40), the save area operation unit 37 determines whether or not to store vehicle data for one block or more in the save area (S110). That is, before actual recording, it is determined whether or not the sum of the size of the vehicle data already written in the save area and the size of the vehicle data to be written is one block. By determining before writing, the size of the save area can be suppressed to 1 block or less.

  When vehicle data for one block or more is not stored in the save area (No in S110), the save area writing unit 36 writes the vehicle data in the empty area of the save area (S120). Further, since the block of the nonvolatile memory 23 should not be erased, the process returns to S10.

  When vehicle data for one block or more is stored in the evacuation area in total (Yes in S110), the block erasing unit 34 erases one block of the nonvolatile memory 23 in units of blocks (S130).

  Next, the evacuation area operation unit 37 copies the vehicle data in the evacuation area to the erased block (S140).

  Then, the latest vehicle data held in the RAM 21 is written into the block erased by the vehicle data writing unit 35 (S150).

  The evacuation area operation unit 37 deletes the vehicle data in the evacuation area (S160).

  The vehicle data writing unit 35 updates the pointer according to the size in which the vehicle data is written (S70). Thus, the pointer indicates the start address of the next vehicle data write destination in the nonvolatile memory 23.

  Thus, by providing the retreat area, when vehicle data is stored across two blocks, the time when the continuity of the straddled vehicle data is lost can be minimized.

[Vehicle data for one block excess]
For example, when vehicle data larger than one block is stored in the save area in step S110, the excess vehicle data will be described.

  FIG. 11A is an example for schematically explaining the relationship between the free space in the save area and the size of the vehicle data. If the vehicle data is larger than the free capacity of the save area, even if the nonvolatile memory 23 is erased for one block, the save area and the vehicle data cannot be stored in one block of the nonvolatile memory 23.

  In such a case, the save area operation unit 37 writes a total of one block into the nonvolatile memory 23 using the save area and the latest vehicle data. Then, only one block that can be stored in one block of the nonvolatile memory 23 among the latest vehicle data is stored, and the excess of one block may be stored in the save memory. In this way, even if there is only one block in the evacuation area, it is possible to deal with vehicle data that exceeds one block.

  Alternatively, as shown in FIG. 11B, two save areas may be provided. In this case, the latest vehicle data stored in the RAM 21 can be temporarily stored in the save area using the fact that the save area has two blocks.

  When the size of the vehicle data stored in the save area becomes 1 block or more, the save area operation unit 37 writes one block of the save area in the nonvolatile memory 23. The excess of one block is stored in the second save memory.

  The save area operation unit 37 stores the next vehicle data in the second save memory, and stores the next vehicle data in the first save area when there is no more free area in the second save area. That is, the save area is also used like a ring buffer. By doing this, two blocks are required for the save area, but the vehicle data writing process can be simplified as compared with FIG.

11 Reception control ECU
12 Transmission control ECU
13 In-vehicle network 21 RAM
22 ROM
23 Non-volatile memory 24 Microcomputer 25 OS / CAN driver 100 Vehicle data recording device

Claims (6)

In an information processing apparatus that stores vehicle data in a nonvolatile ring buffer when a predetermined vehicle situation is detected,
Vehicle data collection means for collecting vehicle data before and after the vehicle situation is detected;
Vehicle data primary storage means for primarily storing vehicle data collected by the vehicle data collection means;
When there is no more free space than the size of the vehicle data, data erasing means for erasing the vehicle data in the ring buffer in the erasing unit block from the oldest
Data writing means for continuously writing the vehicle data stored in the vehicle data primary storage means to the last vehicle data of the ring buffer;
The data erasing means retains the vehicle data of the erasure unit block in which the oldest vehicle data is stored until the vehicle situation is detected even if there is no free space equal to or larger than the size of the vehicle data. Erasing the vehicle data of the erasure unit block in which the oldest vehicle data is stored when it is detected,
An information processing apparatus characterized by that. Save memory of the same size as the erase unit block,
Evacuation area writing means for writing vehicle data to the evacuation memory,
The data erasing means is the oldest vehicle data when the total size of the vehicle data written in the save area and the newly generated vehicle data due to the detection of the vehicle status is equal to or larger than the erase unit block. Erases the vehicle data of the erase unit block in which is stored,
The information processing apparatus according to claim 1. When the total size of the vehicle data written in the evacuation area and the newly generated vehicle data because the vehicle status is detected is larger than the erase unit block,
Write one erasure unit block of the vehicle data written in the evacuation area and the vehicle data newly generated due to the detection of the vehicle status into the empty area of the erasure unit block erased by the data erasure means, 3. The information processing apparatus according to claim 2, further comprising save area operation means for writing an excess of one erase unit block into the save area.   2. The information processing apparatus according to claim 1, wherein the size of the erasure unit block is an integral multiple of the size of the vehicle data.   The information processing apparatus according to any one of claims 1 to 4, wherein the nonvolatile memory is a flash memory, and the vehicle data primary storage means is a volatile random access memory. In a data recording method of an information processing apparatus for storing vehicle data in a non-volatile ring buffer when a predetermined vehicle situation is detected,
Vehicle data collection means collects vehicle data before and after the vehicle situation is detected, and temporarily stores the vehicle data in primary storage means;
A data writing means for writing the vehicle data stored in the vehicle data primary storage means subsequent to the last vehicle data in the ring buffer;
When there is no free space equal to or larger than the size of the vehicle data, the data erasing means holds the vehicle data of the erasure unit block storing the oldest vehicle data until the vehicle situation is detected, and the vehicle situation is Erasing the vehicle data of the erasure unit block in which the oldest vehicle data is stored in response to being detected;
And a data recording method.

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